id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
|---|---|---|---|---|---|---|
69,391,315 | https://en.wikipedia.org/wiki/T-Mobile%204G%20LTE%20CellSpot | The T-Mobile 4G LTE CellSpot is a femtocell released by T-Mobile US in 2015.
Developments
In 2016, Qualcomm announced a collaboration with T-Mobile and Nokia for the development of femtocells.
Versions
The original version and version 2 have been released.
References
External links
FCC ID: H8NSS2FII
Mobile telecommunications
Telecommunications infrastructure
T-Mobile US | T-Mobile 4G LTE CellSpot | [
"Technology"
] | 86 | [
"Mobile telecommunications"
] |
69,391,864 | https://en.wikipedia.org/wiki/Comparison%20of%20programming%20languages%20%28algebraic%20data%20type%29 | This article compares the syntax for defining and instantiating an algebraic data type (ADT), sometimes also referred to as a tagged union, in various programming languages.
Examples of algebraic data types
ATS
In ATS, an ADT may be defined with:
datatype tree =
| Empty of ()
| Node of (int, tree, tree)
And instantiated as:
val my_tree = Node(42, Node(0, Empty, Empty), Empty)
Additionally in ATS dataviewtypes are the linear type version of ADTs for the purpose of providing in the setting of manual memory management with the convenience of pattern matching. An example program might look like:
(* Alternatively one can use the datavtype keyword *)
dataviewtype int_or_string_vt (bool) =
| String_vt (true) of string
| Int_vt (false) of int
(* Alternatively one can use the vtypedef keyword *)
viewtypedef Int_or_String_vt = [b: bool] int_or_string_vt b
fn print_int_or_string (i_or_s: Int_or_String_vt): void =
case+ i_or_s of
(* ~ indicates i_or_s will be implicitly freed in this case *)
| ~String_vt(s) => println!(s)
(* @ indicates i_or_s must be explicitly freed in this case *)
| @Int_vt(i) => begin
$extfcall(void, "fprintf", stdout_ref, "%d\n", i);
free@i_or_s;
end
implement main0 (): void = let
val string_hello_world = String_vt "Hello, world!"
val int_0 = Int_vt 0
in
print_int_or_string string_hello_world;
print_int_or_string int_0;
(* which prints:
Hello, world!
0
*)
end
Ceylon
In Ceylon, an ADT may be defined with:
abstract class Tree()
of empty | Node {}
object empty
extends Tree() {}
final class Node(shared Integer val, shared Tree left, shared Tree right)
extends Tree() {}
And instantiated as:
value myTree = Node(42, Node(0, empty, empty), empty);
Clean
In Clean, an ADT may be defined with:
:: Tree
= Empty
| Node Int Tree Tree
And instantiated as:
myTree = Node 42 (Node 0 Empty Empty) Empty
Coq
In Coq, an ADT may be defined with:
Inductive tree : Type :=
| empty : tree
| node : nat -> tree -> tree -> tree.
And instantiated as:
Definition my_tree := node 42 (node 0 empty empty) empty.
C++
In C++, an ADT may be defined with:
struct Empty final {};
struct Node final {
int value;
std::unique_ptr<std::variant<Empty, Node>> left;
std::unique_ptr<std::variant<Empty, Node>> right;
};
using Tree = std::variant<Empty, Node>;
And instantiated as:
Tree myTree { Node{
42,
std::make_unique<Tree>(Node{
0,
std::make_unique<Tree>(),
std::make_unique<Tree>()
}),
std::make_unique<Tree>()
} };
Dart
In Dart, an ADT may be defined with:
sealed class Tree {}
final class Empty extends Tree {}
final class Node extends Tree {
final int value;
final Tree left, right;
Node(this.value, this.left, this.right);
}
And instantiated as:
final myTree = Node(42, Node(0, Empty(), Empty()), Empty());
Elm
In Elm, an ADT may be defined with:
type Tree
= Empty
| Node Int Tree Tree
And instantiated as:
myTree = Node 42 (Node 0 Empty Empty) Empty
F#
In F#, an ADT may be defined with:
type Tree =
| Empty
| Node of int * Tree * Tree
And instantiated as:
let myTree = Node(42, Node(0, Empty, Empty), Empty)
F*
In F*, an ADT may be defined with:
type tree =
| Empty : tree
| Node : value:nat -> left:tree -> right:tree -> tree
And instantiated as:
let my_tree = Node 42 (Node 0 Empty Empty) Empty
Free Pascal
In Free Pascal (in standard ISO Pascal mode), an ADT may be defined with variant records:
{$mode ISO}
program MakeTree;
type TreeKind = (Empty, Node);
PTree = ^Tree;
Tree = record
case Kind: TreeKind of
Empty: ();
Node: (
Value: Integer;
Left, Right: PTree;
);
end;
And instantiated as:
var MyTree: PTree;
begin new(MyTree, Node);
with MyTree^ do begin
Value := 42;
new(Left, Node);
with Left^ do begin
Value := 0;
new(Left, Empty);
new(Right, Empty);
end;
new(Right, Empty);
end;
end.
Haskell
In Haskell, an ADT may be defined with:
data Tree
= Empty
| Node Int Tree Tree
And instantiated as:
myTree = Node 42 (Node 0 Empty Empty) Empty
Haxe
In Haxe, an ADT may be defined with:
enum Tree {
Empty;
Node(value:Int, left:Tree, right:Tree);
}
And instantiated as:
var myTree = Node(42, Node(0, Empty, Empty), Empty);
Hope
In Hope, an ADT may be defined with:
data tree == empty
++ node (num # tree # tree);
And instantiated as:
dec mytree : tree;
--- mytree <= node (42, node (0, empty, empty), empty);
Idris
In Idris, an ADT may be defined with:
data Tree
= Empty
| Node Nat Tree Tree
And instantiated as:
myTree : Tree
myTree = Node 42 (Node 0 Empty Empty) Empty
Java
In Java, an ADT may be defined with:
sealed interface Tree {
record Empty() implements Tree {}
record Node(int value, Tree left, Tree right) implements Tree {}
}
And instantiated as:
var myTree = new Tree.Node(
42,
new Tree.Node(0, new Tree.Empty(), new Tree.Empty()),
new Tree.Empty()
);
Julia
In Julia, an ADT may be defined with:
struct Empty
end
struct Node
value::Int
left::Union{Empty, Node}
right::Union{Empty, Node}
end
const Tree = Union{Empty, Node}
And instantiated as:
mytree = Node(42, Node(0, Empty(), Empty()), Empty())
Kotlin
In Kotlin, an ADT may be defined with:
sealed class Tree {
object Empty : Tree()
data class Node(val value: Int, val left: Tree, val right: Tree) : Tree()
}
And instantiated as:
val myTree = Tree.Node(
42,
Tree.Node(0, Tree.Empty, Tree.Empty),
Tree.Empty,
)
Limbo
In Limbo, an ADT may be defined with:
Tree: adt {
pick {
Empty =>
Node =>
value: int;
left: ref Tree;
right: ref Tree;
}
};
And instantiated as:
myTree := ref Tree.Node(
42,
ref Tree.Node(0, ref Tree.Empty(), ref Tree.Empty()),
ref Tree.Empty()
);
Mercury
In Mercury, an ADT may be defined with:
:- type tree
---> empty
; node(int, tree, tree).
And instantiated as:
:- func my_tree = tree.
my_tree = node(42, node(0, empty, empty), empty).
Miranda
In Miranda, an ADT may be defined with:
tree ::=
Empty
| Node num tree tree
And instantiated as:
my_tree = Node 42 (Node 0 Empty Empty) Empty
Nemerle
In Nemerle, an ADT may be defined with:
variant Tree
{
| Empty
| Node {
value: int;
left: Tree;
right: Tree;
}
}
And instantiated as:
def myTree = Tree.Node(
42,
Tree.Node(0, Tree.Empty(), Tree.Empty()),
Tree.Empty(),
);
Nim
In Nim, an ADT may be defined with:
type
TreeKind = enum
tkEmpty
tkNode
Tree = ref TreeObj
TreeObj = object
case kind: TreeKind
of tkEmpty:
discard
of tkNode:
value: int
left, right: Tree
And instantiated as:
let myTree = Tree(kind: tkNode, value: 42,
left: Tree(kind: tkNode, value: 0,
left: Tree(kind: tkEmpty),
right: Tree(kind: tkEmpty)),
right: Tree(kind: tkEmpty))
OCaml
In OCaml, an ADT may be defined with:
type tree =
| Empty
| Node of int * tree * tree
And instantiated as:
let my_tree = Node (42, Node (0, Empty, Empty), Empty)
Opa
In Opa, an ADT may be defined with:
type tree =
{ empty } or
{ node, int value, tree left, tree right }
And instantiated as:
my_tree = {
node,
value: 42,
left: {
node,
value: 0,
left: { empty },
right: { empty }
},
right: { empty }
}
OpenCog
In OpenCog, an ADT may be defined with:
PureScript
In PureScript, an ADT may be defined with:
data Tree
= Empty
| Node Int Tree Tree
And instantiated as:
myTree = Node 42 (Node 0 Empty Empty) Empty
Python
In Python, an ADT may be defined with:
from __future__ import annotations
from dataclasses import dataclass
@dataclass
class Empty:
pass
@dataclass
class Node:
value: int
left: Tree
right: Tree
Tree = Empty | Node
And instantiated as:
my_tree = Node(42, Node(0, Empty(), Empty()), Empty())
Racket
In Typed Racket, an ADT may be defined with:
(struct Empty ())
(struct Node ([value : Integer] [left : Tree] [right : Tree]))
(define-type Tree (U Empty Node))
And instantiated as:
(define my-tree (Node 42 (Node 0 (Empty) (Empty)) (Empty)))
Reason
Reason
In Reason, an ADT may be defined with:
type Tree =
| Empty
| Node(int, Tree, Tree);
And instantiated as:
let myTree = Node(42, Node(0, Empty, Empty), Empty);
ReScript
In ReScript, an ADT may be defined with:
type rec Tree =
| Empty
| Node(int, Tree, Tree)
And instantiated as:
let myTree = Node(42, Node(0, Empty, Empty), Empty)
Rust
In Rust, an ADT may be defined with:
enum Tree {
Empty,
Node(i32, Box<Tree>, Box<Tree>),
}
And instantiated as:
let my_tree = Tree::Node(
42,
Box::new(Tree::Node(0, Box::new(Tree::Empty), Box::new(Tree::Empty)),
Box::new(Tree::Empty),
);
Scala
Scala 2
In Scala 2, an ADT may be defined with:
sealed abstract class Tree extends Product with Serializable
object Tree {
final case object Empty extends Tree
final case class Node(value: Int, left: Tree, right: Tree)
extends Tree
}
And instantiated as:
val myTree = Tree.Node(
42,
Tree.Node(0, Tree.Empty, Tree.Empty),
Tree.Empty
)
Scala 3
In Scala 3, an ADT may be defined with:
enum Tree:
case Empty
case Node(value: Int, left: Tree, right: Tree)
And instantiated as:
val myTree = Tree.Node(
42,
Tree.Node(0, Tree.Empty, Tree.Empty),
Tree.Empty
)
Standard ML
In Standard ML, an ADT may be defined with:
datatype tree =
EMPTY
| NODE of int * tree * tree
And instantiated as:
val myTree = NODE (42, NODE (0, EMPTY, EMPTY), EMPTY)
Swift
In Swift, an ADT may be defined with:
enum Tree {
case empty
indirect case node(Int, Tree, Tree)
}
And instantiated as:
let myTree: Tree = .node(42, .node(0, .empty, .empty), .empty)
TypeScript
In TypeScript, an ADT may be defined with:
type Tree =
| { kind: "empty" }
| { kind: "node"; value: number; left: Tree; right: Tree };
And instantiated as:
const myTree: Tree = {
kind: "node",
value: 42,
left: {
kind: "node",
value: 0,
left: { kind: "empty" },
right: { kind: "empty" },
},
right: { kind: "empty" },
};
Visual Prolog
In Visual Prolog, an ADT may be defined with:
domains
tree = empty; node(integer, tree, tree).
And instantiated as:
constants
my_tree : tree = node(42, node(0, empty, empty), empty).
Zig
In Zig, an ADT may be defined with:
const Tree = union(enum) {
empty,
node: struct {
value: i32,
left: *const Tree,
right: *const Tree,
},
};
And instantiated as:
const my_tree: Tree = .{ .node = .{
.value = 42,
.left = &.{ .node = .{
.value = 0,
.left = &.empty,
.right = &.empty,
} },
.right = &.empty,
} };
References
Algebraic data type
Articles with example C++ code
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Articles with example Swift code | Comparison of programming languages (algebraic data type) | [
"Technology"
] | 3,262 | [
"Programming language comparisons",
"Computing comparisons"
] |
69,392,090 | https://en.wikipedia.org/wiki/Transition%20metal%20nitrate%20complex | A transition metal nitrate complex is a coordination compound containing one or more nitrate ligands. Such complexes are common starting reagents for the preparation of other compounds.
Ligand properties
Being the conjugate base of a strong acid (nitric acid, pKa = -1.4), nitrate has modest Lewis basicity. Two coordination modes are common: unidentate and bidentate. Often, bidentate nitrate, denoted κ2-NO3, is bound unsymmetrically in the sense that one M-O distance is clearly bonding and the other is more weakly interacting. The MO-N distances for the coordinated oxygen are longer by about 10 picometers longer than the N-Oterminal bonds. This observation suggests that the terminal N-O bonds have double bond character. Nitrate is isostructural with but less basic than carbonate. Both exhibit comparable coordination geometries. The nitrogen center of nitrate does not form bonds to metals.
Coordination complexes
With three terminal oxide groups, nitrate can in principle bind metals through many geometries. Even though the ligand is written as MNO3, the oxygen atoms are invariably coordinated. Thus, monodentate nitrate is illustrated by [Co(NH3)5NO3]2+, which could also be written as [Co(NH3)5ONO2]2+. Homoleptic metal nitrate complexes generally have O,O'-bidentate nitrate ligands.
Hydrates
Typical metal nitrates are hydrated. Some of these salts crystallize with one or more nitrate ligands, but most are assumed to dissolve in water to give aquo complexes, often of the stoichiometry [M(H2O)6]n+.
Cr(NO3)3(H2O)6
Mn(NO3)2(H2O)4
Fe(NO3)3(H2O)9
Co(NO3)2(H2O)2
Ni(NO3)2(H2O)4
Pd(NO3)2(H2O)2
Cu(NO3)2(H2O)x
Zn(NO3)2(H2O)4
Hg2(NO3)2(H2O)2
Synthesis
Metal nitrate complexes are often prepared by treating metal oxides or metal carbonates with nitric acid. The main complication with dissolving metals in nitric acid arises from redox reactions, which can afford either nitric oxide or nitrogen dioxide.
Anhydrous nitrates can be prepared by the oxidation of metals with dinitrogen tetroxide (often as a mixture with nitrogen dioxide, with which it interconverts). N2O4 undergoes molecular autoionization to give [NO+] [NO3−], with the former nitrosonium ion being a strong oxidant. The method is illustrated by the route to β-Cu(NO3)2:
Cu + 2N2O4 → Cu(NO3)2 + 2NO
Many metals, metal halides, and metal carbonyls undergo similar reactions, but the product formulas can be deceptive. For example from chromium one obtains Cr(NO3)3(N2O4)2, which was shown to be the salt (NO+)2[Cr(NO3)5]2-. Nitrogen oxides readily interconvert between various forms, some of which may act as completing ligands. The redox reaction of nitrosonium and the metal can give rise to nitrogen oxide which forms strong metal nitrosyl complexes; nitronium ions (NO2+) are similarly observed.
In some cases, nitrate complexes are produced from the reaction of nitrogen dioxide with a metal dioxygen complex:
(PPh3 = triphenylphosphine)
Reactions
Given nitrate's low basicity, the tendency of metal nitrate complexes toward hydrolysis is expected. Thus copper(II) nitrate readily dissociates in aqueous solution to give the aqua complex:
Cu(NO3)2 + 6 H2O → [Cu(H2O)6](NO3)2
Pyrolysis of metal nitrates yields oxides.
Ni(NO3)2 → NiO + NO2 + 0.5O2
This reaction is used to impregnate oxide supports with nickel oxides.
Nitrate reductase enzymes convert nitrate to nitrite. The mechanism involves the intermediacy of Mo-ONO2 complexes.
References
Nitrates | Transition metal nitrate complex | [
"Chemistry"
] | 942 | [
"Oxidizing agents",
"Nitrates",
"Salts"
] |
69,392,163 | https://en.wikipedia.org/wiki/Blow-up%20lemma | The blow-up lemma, proved by János Komlós, Gábor N. Sárközy, and Endre Szemerédi in 1997, is an important result in extremal graph theory, particularly within the context of the regularity method. It states that the regular pairs in the statement of Szemerédi's regularity lemma behave like complete bipartite graphs in the context of embedding spanning graphs of bounded degree.
Definitions and Statement
To formally state the blow-up lemma, we first need to define the notion of a super-regular pair.
Super-regular pairs
A pair of subsets of the vertex set is called -super-regular if for every and satisfying
and
we have
and furthermore,
for all and for all .
Here denotes the number of pairs with and such that is an edge.
Statement of the Blow-up Lemma
Given a graph of order and positive parameters , there exists a positive such that the following holds. Let be arbitrary positive integers and let us replace the vertices of with pairwise disjoint sets of sizes (blowing up). We construct two graphs on the same vertex set . The first graph is obtained by replacing each edge of with the complete bipartite graph between the corresponding vertex sets and . A sparser graph G is constructed by replacing each edge with an -super-regular pair between and . If a graph with is embeddable into then it is already embeddable into G.
Proof Sketch
The proof of the blow-up lemma is based on using a randomized greedy algorithm (RGA) to embed the vertices of into sequentially. The argument then proceeds by bounding the failure rate of the algorithm such that it is less than 1 (and in fact ) for an appropriate choice of parameters. This means that there is a non-zero chance for the algorithm to succeed, so an embedding must exist.
Attempting to directly embed all the vertices of in this manner does not work because the algorithm may get stuck when only a small number of vertices are left. Instead, we set aside a small fraction of the vertex set, called buffer vertices, and attempt to embed the rest of the vertices. The buffer vertices are subsequently embedded by using Hall's marriage theorem to find a perfect matching between the buffer vertices and the remaining vertices of .
Notation
We borrow all notation introduced in previous sections. Let . Since can be embedded into , we can write with for all . For a vertex , let denote . For ,
denotes the density of edges between the corresponding vertex sets of . is the embedding that we wish to construct. is the final time after which the algorithm concludes.
Outline of the algorithm
Phase 0: Initialization
Greedily choose the set of buffer vertices from the vertices of as a maximal set of vertices distance at least from each other
Order the remaining vertices (those in ) in a list , placing the neighbors of first.
Declare a queue of presently prioritized vertices, which is initially empty.
Declare an array of sets indexed by the vertices of , representing the set of all "free spots" of , that is, the set of unoccupied vertices in the vertex could be mapped to without violating any of the adjacency conditions from the already-embedded neighbors of in . is initialized to .
Phase 1: Randomized Greedy Embedding
Choose a vertex from the set of remaining vertices as follows:
If the queue of prioritized vertices is non-empty, then choose the vertex from
Otherwise, choose a vertex from the list of remaining vertices
Choose the image in for the vertex randomly from the set of "good" choices, where a choice is good iff none of the new free-sets differ too much in size from the expected value.
Update the free sets , and put vertices whose free sets have become too small with respect to their size in the last update in the set of prioritized vertices
Abort if the queue contains a sufficiently large fraction of any of the sets
If there are non-buffer vertices left to be embedded in either or , update time and go back to step 1; otherwise move on to phase 2.
Phase 2: Kőnig-Hall matching for remaining vertices
Consider the set of vertices left to be embedded, which is precisely , and the set of free spots . Form a bipartite graph between these two sets, joining each to , and find a perfect matching in this bipartite graph. Embed according to this matching.
Proof of correctness
The proof of correctness is technical and quite involved, so we omit the details. The core argument proceeds as follows:
Step 1: most vertices are good, and enough vertices are free
Prove simultaneously by induction on that if is the vertex embedded at time , then
only a small fraction of the choices in are bad
all of the free sets are fairly large for unembedded vertices
Step 2: the "main lemma"
Consider , and such that is not too small. Consider the event where
no vertices are embedded in during the first phase
for every there is a time such that the fraction of free vertices of in at time was small.
Then, we prove that the probability of happening is low.
Step 3: phase 1 succeeds with high probability
The only way that the first phase could fail is if it aborts, since by the first step we know that there is always a sufficient choice of good vertices. The program aborts only when the queue is too long. The argument then proceeds by union-bounding over all modes of failure, noting that for any particular choice of , and with representing a subset of the queue that failed, the triple satisfy the conditions of the "main lemma", and thus have a low probability of occurring.
Step 4: no queue in initial phase
Recall that the list was set up so that neighbors of vertices in the buffer get embedded first. The time until all of these vertices get embedded is called the initial phase. Prove by induction on that no vertices get added to the queue during the initial phase. It follows that all of the neighbors of the buffer vertices get added before the rest of the vertices.
Step 5: buffer vertices have enough free spots
For any and , we can find a sufficiently large lower bound on the probability that , conditional on the assumption that was free before any of the vertices in were embedded.
Step 6: phase 2 succeeds with high probability
By Hall's marriage theorem, phase 2 fails if and only if Hall's condition is violated. For this to happen, there must be some and such that . cannot be too small by largeness of free sets (step 1). If is too large, then with high probability , so the probability of failure in such a case would be low. If is neither too small nor too large, then noting that is a large set of unused vertices, we can use the main lemma and union-bound the failure probability.
Applications
The blow-up lemma has a number of applications in embedding dense graphs.
Pósa-Seymour Conjecture
In 1962, Lajos Pósa conjectured that every -vertex graph with minimum degree at least contains the square of a Hamiltonian cycle, generalizing Dirac's theorem. The conjecture was further extended by Paul Seymour in 1974 to the following:
Every graph on vertices with minimum degree at least contains the -th power of a Hamiltonian cycle.
The blow-up lemma was used by Komlós, Sárközy, and Szemerédi to prove the conjecture for all sufficiently large values of (for a fixed ) in 1998.
Alon-Yuster Conjecture
In 1995, Noga Alon and Raphael Yuster considered the generalization of the well-known Hajnal–Szemerédi theorem to arbitrary -factors (instead of just complete graphs), and proved the following statement:
For every fixed graph with vertices, any graph G with n vertices and with minimum degree contains vertex disjoint copies of H.
They also conjectured that the result holds with only a constant (instead of linear) error:
For every integer there exists a constant such that for every graph with vertices, any graph with vertices and with minimum degree contains at least vertex disjoint copies of .
This conjecture was proven by Komlós, Sárközy, and Szemerédi in 2001 using the blow-up lemma.
History and Variants
The blow-up lemma, first published in 1997 by Komlós, Sárközy, and Szemerédi, emerged as a refinement of existing proof techniques using the regularity method to embed spanning graphs, as in the proof of the Bollobás conjecture on spanning trees, work on the Pósa-Seymour conjecture about the minimum degree necessary to contain the k-th graph power of a Hamiltonian cycle, and the proof of the Alon-Yuster conjecture on the minimum degree needed for a graph to have a perfect H-factor. The proofs of all of these theorems relied on using a randomized greedy algorithm to embed the majority of vertices, and then using a Kőnig-Hall like argument to find an embedding for the remaining vertices. The first proof of the blow-up lemma also used a similar argument. Later in 1997, however, the same authors published another paper that found an improvement to the randomized algorithm to make it deterministic.
Peter Keevash found a generalization of the blow-up lemma to hypergraphs in 2010.
Stefan Glock and Felix Joos discovered a variant of the blow-up lemma for rainbow graphs in 2018.
In 2019, Peter Allen, Julia Böttcher, Hiep Hàn, Yoshiharu Kohayakawa, and Yury Person, found sparse analogues of the blow-up lemma for embedding bounded degree graphs into random and pseudorandom graphs
References
Extremal graph theory
Lemmas in graph theory | Blow-up lemma | [
"Mathematics"
] | 2,015 | [
"Graph theory",
"Lemmas in graph theory",
"Mathematical relations",
"Extremal graph theory",
"Lemmas"
] |
69,392,210 | https://en.wikipedia.org/wiki/Neuroecology | Neuroecology studies ways in which the structure and function of the brain results from adaptations to a specific habitat and niche.
It integrates the multiple disciplines of neuroscience, which examines the biological basis of cognitive and emotional processes, such as perception, memory, and decision-making, with the field of ecology, which studies the relationship between living organisms and their physical environment.
In biology, the term 'adaptation' signifies the way evolutionary processes enhance an organism's fitness to survive within a specific ecological context. This fitness includes the development of physical, cognitive, and emotional adaptations specifically suited to the environmental conditions in which the organism or phenotype lives, and in which its species or genotype evolves.
Neuroecology concentrates specifically on neurological adaptations, particularly those of the brain. The purview of this study encompasses two areas. Firstly, neuroecology studies how the physical structure and functional activity of neural networks in a phenotype is influenced by characteristics of the environmental context. This includes the way social stressors, interpersonal relationships, and physical conditions precipitate persistent alterations in the individual brain, providing the neural correlates of cognitive and emotional responses. Secondly, neuroecology studies how neural structure and activity common to a genotype is determined by natural selection of traits that benefit survival and reproduction in a specific environment.
See also
Evolutionary ecology
Evolutionary psychology
References
External links
Cognitive Neuroecology Lab at the FMRIB Centre of the University of Oxford (UK) and Donders Institute in Nijmegen (Netherlands)
Behavioral neuroscience
Evolutionary biology
Ecology terminology
Ecology | Neuroecology | [
"Biology"
] | 322 | [
"Evolutionary biology",
"Ecology terminology",
"Behavior",
"Behavioral neuroscience",
"Ecology",
"Behavioural sciences"
] |
69,393,288 | https://en.wikipedia.org/wiki/Lenovo%20ThinkPad%20T410 | The Lenovo ThinkPad T410 is a laptop from the ThinkPad series manufactured by Lenovo. The Lenovo ThinkPad T410s was also released. In 2014 Lenovo issued a product recall, dated April 1, on specific ranges of Thinkpad series batteries which had shipped from October 2010 to April 2011 due to a potential fire hazard, including some shipping with or for the model T410.
References
ThinkPad T410
T410
Computer-related introductions in 2010 | Lenovo ThinkPad T410 | [
"Technology"
] | 99 | [
"Computing stubs",
"Computer hardware stubs"
] |
69,393,330 | https://en.wikipedia.org/wiki/Lenovo%20ThinkPad%20W700 | The Lenovo ThinkPad W700 is a laptop that was manufactured by Lenovo.
Reception
LaptopMag gave it 4/5 stars and noted its good 3D performance, built-in Wacom digitizer and good display with color calibration. Christopher Null from Wired magazine gave it a 7/10.
Successor
The W701ds was released in February 2010, after specifications were leaked earlier that month. The W701ds had an introduction price of 3799 USD. At the time of the release, Lenovo stated that according to their market research, customers did not want devices with a slate form factor.
References
External links
thinkwiki.org - W700
thinkwiki.de - W700
ThinkPad W700
W700
Computer-related introductions in 2008 | Lenovo ThinkPad W700 | [
"Technology"
] | 163 | [
"Mobile computer stubs",
"Mobile technology stubs"
] |
69,394,644 | https://en.wikipedia.org/wiki/Defence%20Secretariat%2019 | Defence Secretariat 19 (DS19) was a special unit set up within the British Ministry of Defence by Michael Heseltine in March 1983. Its purpose was to combat the Campaign for Nuclear Disarmament (CND) and all calls for unilateral nuclear disarmament.
References
See also
Women and Families for Defence
Ministry of Defence (United Kingdom)
Politics of the United Kingdom
Cold War
Nuclear organizations
Anti–nuclear weapons movement | Defence Secretariat 19 | [
"Engineering"
] | 88 | [
"Nuclear organizations",
"Energy organizations"
] |
69,395,571 | https://en.wikipedia.org/wiki/Dispersion%20stabilized%20molecules | Dispersion stabilized molecules are molecules where the London dispersion force (LDF), a non-covalent attractive force between atoms and molecules, plays a significant role in promoting the molecule's stability. Distinct from steric hindrance, dispersion stabilization has only recently been considered in depth by organic and inorganic chemists after earlier gaining prominence in protein science and supramolecular chemistry. Although usually weaker than covalent bonding and other forms of non-covalent interactions like hydrogen bonding, dispersion forces are known to be a significant if not dominating stabilizing force in certain organic, inorganic, and main group molecules, stabilizing otherwise reactive moieties and exotic bonding.
Stabilization through dispersion
Dispersion interactions are a stabilizing force arising from quantum mechanical electron correlation. Although quantum mechanical in nature, the energy of dispersion interactions can be approximated classically, showing a R−6 dependence on the distance between two atoms. This distance dependence helps make dispersion interactions weak for individual atoms and has led to dispersion effects being historically neglected in molecular chemistry. However, in larger molecules dispersion effects can become significant. Dispersion forces in molecular chemistry are most apparent in molecules with large, bulky functional groups. Dispersion stabilization is often signified by atomic contacts below their van der Waals radii in a molecule's crystal structure. Especially for H•••H contacts between bulky, rigid, polarizable groups, short contacts may indicate that a dispersion force is overcoming the Pauli repulsion present between the two H atoms.
Dispersion forces stabilizing a reactive moiety within a molecule is distinct from using steric bulk to protect that reactive moiety. Adding "steric hindrance" to a molecule's reactive site through bulky groups is a common strategy in molecular chemistry to stabilize reactive moieties within a molecule. In this case bulky ligands like terphenyls, bulky alkoxides, aryl-substituted NHCs, etc. serve as a protective wrapper on the molecule. Under the steric hindrance model, the filled orbitals of a bulky group repel other molecules and/or functional groups through Pauli repulsion. These bulky groups inhibit the approach to a molecule's reactive site, kinetically stabilizing the molecule. By contrast dispersion stabilization occurs when these bulky ligands form energetically favorable non-covalent interactions. In molecules where dispersion forces are a dominant factor, the attractive interactions between bulky groups is greater than repulsive interactions between the groups, providing overall thermodynamic stability to the molecule. Although dispersion stabilization and steric hindrance are distinct, dispersion stabilized molecules frequently benefit from steric protection of the molecule's reactive moiety.
Molecular dispersion in computational chemistry
Advances in quantum computational chemistry methods have allowed for faster theoretical examination of dispersion effects in molecular chemistry. Standard density functional theory (DFT) does not account well for dispersion effects, but corrections like the popular -D3 correction can be used with DFT to provide efficient dispersion energy corrections. The -D3 correction is a force field type correction that does not take into account electronic structure, but nonetheless the popular correction works with many functionals and produces values that often fall within 5-10% of more sophisticated calculations. The "gold standard" computational method are coupled-cluster methods like CCSD(T) that account for the electron correlation origin of dispersion interactions.
Richard Bader's theory of Atoms in Molecules (AIM) has also been invoked to computationally identify dispersion interactions. Bader proposed that a bond critical point, or a critical point in the electron density, between two electronically similar, closed-shell hydrogen atoms is evidence for a stabilizing dispersion interaction between those two atoms. Although there is controversy about accepting bond critical points as evidence for net attractive interactions, AIM analysis has been invoked by different research groups to show dispersion effects in a variety of molecules.
Alternative computational analysis methods include Yang's electron density based non-covalent interaction (NCI) analysis, and the local energy decomposition (LED) analysis to produce a dispersion interaction density (DID) plot.
Example molecules
Organic chemistry
Dispersion stabilization explains the reactivity patterns of bulky hydrocarbon radicals. •CPh3 radicals have been known since 1900. In the mid-1960s, the dimer form of the radical was observed, and instead of forming the expected Ph3CCPh3 product, the radical instead undergoes head to tail addition. By contrast, adding two tBu groups to the meta positions on the phenyl rings causes the radical to readily dimerize to (3,5-tBu2H3C6)3C–C(C6H3-3,5-tBu2)3. Initially this discovery puzzled researchers because •CPh3 head-to-tail addition seemed to suggest steric repulsion disfavored direct addition; however, the more sterically crowded molecule underwent head-to-head addition. More recently, computational analysis has shown the formation of the tBu substituted dimer to be stabilized through dispersion interactions. The study suggests that dispersion interactions between tBu groups provide ~60kcal/mol of stabilization to the molecule, enough to overcome the unfavorable steric interactions from the additional tBu groups. Further, the dimer contains a 1.67Å C-C single bond, much longer than the canonical 1.54Å C-C single bond. Despite the long C-C bond, the molecule remains stable at room temperature through dispersion based stability.
Beyond just the tBu substituted hexaphenylethane, Schriener and coworkers have synthesized new molecules with "dispersion energy donors" to form both long C-C bonds and short H•••H contacts. The effect of dispersion stabilization was further probed with a series of meta-substituted hexaphenylethane molecules substituted with Me, iPr, tBu, Cy, and adamantyl groups. Of these molecules, only the tBu and adamantyl analogs were observed to form the head-to-head dimer, showing the sensitivity of dispersion stabilization to rigid, polarizable substituents. Dispersion stabilization has additionally been used to stabilize intermolecular contacts. When the (3,5-tBu2H3C6)3CH molecule dimerizes to form [(3,5-tBu2H3C6)3CH]2, stabilizing interactions between tBu groups bring the central pair of hydrogens to a contact distance of 1.566Å as determined by neutron diffraction. This distance is well within the combined van der Waals radii of the two H atoms, and at the time was the shortest reported H•••H contact.Researchers have posited that the stability of the bulky hydrocarbon tetra(tert-butyl)tetrahedrane is in part from dispersion forces. Originally, the molecule's thermal stability in air up to 135 °C was attributed to the corset effect, wherein any stability gained by elongating a C-C bond to release ring strain would be countered by increased repulsion between the remaining tBu groups. Although the corset effect is the dominant force driving stability, this explanation has been recently supplemented with calculations that show the tBu groups provide 3.1 kcal/mol of stability to the molecule.
Inorganic chemistry
Dispersion forces can stabilize reactive organometallic molecules by using bulky ligands in metal complexes. The first two-coordinate linear Cu(II) complex, Cu{N(SiMe3)Dipp}2 (Dipp = C6H5-2,6iPr2), was prepared by combining a 1:1 ratio of LiN(SiMe3)Dipp and CuCl. The mechanism of this reaction is unknown, but the net result is Cu disproportionation to form the Cu(II) complex and Cu metal. The authors suggest that a dispersion stabilization of about 25 kcal/mol from the bulky ligands assists in the initial disproportionation reaction and that this stabilization prevents crystals of the complex from decomposing via further disproportionation to DippN=NDipp, N-(SiMe3)2Dipp, and Cu metal. The complex's eclipsed ligand conformation further suggests that dispersion stabilizes the low coordinate complex.
Metal tetranorbornyls, M(nor)4 (1-nor = 4bicyclo[2.2.1]hept-1-yl, M = Fe, Co), benefit from stability imparted by dispersion. The compounds display high stability for a formally 4+ oxidation state metal center, which has traditionally been attributed to unfavorable β-elimination. Computational work has determined that the close norbornyl contacts are worth -45.9 kcal/mol of energy, providing significant stabilization to the molecule.
Main group chemistry
Researches have used dispersion stabilization to promote unusual main group bonding. Dispersion forces have been shown to stabilize a cyclic silylated plumbylene dimer, which shows different Pb-Pb bonding than in the parent parent diplumbene (Pb2H4). The crystal structure of the silylated plumbylene dimer has different geometries about each Pb atom, indicating that the molecule forms a singular donor-acceptor interaction. By contrast, the Pb atoms in Pb2H4 participate in a double donor-acceptor interaction giving the molecule a trans-bent structure. Computational investigations reveal that the silylated dimer has roughly twice the bond dissociation energy of parent diplumbene Pb2H4 despite the parent diplumbene having a higher Wiberg Bond Index. The authors suggest through DFT calculations that dispersion forces between bulky trimethylsilyl groups determine the dimer's conformation.Dispersion has been implicated in stabilizing a Ga-substituted doubly bonded dipnictenes of the form [L(X)Ga]2E2 where E = As, Sb, Bi and L = C[C(Me)N(2,6-iPr2-C6H3). Researchers synthesized the As version of the molecule and computationally analyzed the full series. By calculating the energy of the molecules with and without dispersion, it was determined that dispersion nearly doubles the dimer's enthalpic stabilization when formed from the monomer. In this case, dispersion couples with electronics to provide stability to the molecule.
The thermal stability of an extended Si-Si bond in tBu3SiSitBu3, or superdisilane, has also been attributed to dispersion interactions. Superdisilane has a Si-Si bond length of 2.697Å in the solid state, significantly extended compared to the gas phase Si-Si bond length of 2.331Å in the parent disilane H3SiSiH3. Despite the long bond length, superdisilane exhibits thermal stability up to 323K. Dispersion forces keep the molecule inert even while its core Si-Si bond lengthens. Similarly, the longest known Ge-Ge bond is found in tBu3GeGetBu3 and is also facilitated by dispersion stabilization.
Dispersion stabilization has also been invoked for (tBuC)3P, a main group analog of a hydrocarbon tetrahedrane. Monophosphatetrahedrane, (tBuC)3P, displays greater thermal stability than diphosphatetrahedrane, (tBuCP)2, which decomposes at just -32 °C. The additional stability has been attributed to dispersion interactions between the adjacent, bulky tBu groups. Through computational analysis, the authors identified 9 H-H interactions that each provide -0.7 kcal/mol of energy, overcoming the steric penalty of bringing the tBu groups together. Geometry optimizations with tBu groups swapped for less bulky hydrogens cause significant molecule shape change, indicating that dispersion plays a significant role in stabilizing the molecule's structure.
Applications
Dispersion stabilized molecules are an active area of research. Presently dispersion interactions have mostly been examined after the synthesis of molecules, but molecular design with dispersion effects in mind has generated some excitement for potential future applications. The dispersion interaction effect has been compared to the emerging work on frustrated Lewis pairs, and there is speculation that dispersion could be useful in future catalysis.
References
Van der Waals molecules | Dispersion stabilized molecules | [
"Physics",
"Chemistry"
] | 2,659 | [
"Molecules",
"Matter",
"Van der Waals molecules"
] |
69,396,356 | https://en.wikipedia.org/wiki/Friction%20Acoustics | Solid bodies in contact that undergo shear relative motion (friction) radiate energy. Part of this energy is radiated directly into the surrounding fluid media, and another part radiates throughout the solid bides and the connecting boundary conditions. The coupling of structural vibration and acoustic radiation takes is rooted in the mechanism of atomic oscillations, by which kinetic energy is translated to thermal energy.
This field involves principles of acoustics, solid mechanics, contact dynamics, and tribology.
Coupling and Stick-Slip
Vibrational energy induced by either kinetic or breakaway friction can cause modal excitation of a subset of the contacting bodies or the vibratory coupling of the multiple bodies, depending on the strength of coupling.
Friction noise can be the product of multiple distinct dynamic processes, sliding and stick-slip. Sliding generally leads to stick-slip under a decreasing friction-velocity relation, or other unstable oscillations.
Weak Contact
When normal forces are low, the solid bodies vibratory modes are weakly excited. The resulting noise generated is known as roughness noise. This noise is largely broad-band near the surface, and radiation efficiency and material geometry dictates which frequency content is radiated into the far field.
Surfaces that are relatively smooth, or well-lubricated, low normal forces, and low relative velocities are prone to set conditions for this regime, and avoid stick-slip.
Strong Contact
Under some conditions, the radiated energy is high at the mechanical eigenmodes of the coupled system. This conditions is more likely under higher roughness, higher normal loads, and higher relative sliding velocities.
Empirical Relationships
A review of observed relationships between sound pressure due to friction and parameters such as normal force, roughness, and sliding velocity is provided by Feng et al.
References
Friction
Acoustics | Friction Acoustics | [
"Physics",
"Chemistry"
] | 370 | [
"Mechanical phenomena",
"Physical phenomena",
"Force",
"Friction",
"Physical quantities",
"Classical mechanics",
"Acoustics",
"Surface science"
] |
69,396,442 | https://en.wikipedia.org/wiki/Lp%20solve | lp_solve is a free software command line utility and library for solving linear programming and mixed integer programming problems.
It ships with support for two file formats, MPS and lp_solve's own LP format. User-defined formats are supported via its "eXternal Language Interface" (XLI)
lp_solve also supports translating between model formats using the -w series of command line switches
lp_solve uses the simplex method for linear programs, and branch-and-bound for mixed integer programs.
Multiple pivoting strategies are supported, including devex.
lp_solve also features a pre-solver that can remove redundant variables and remove or tighten constraints.
The lp_solve project also features an integrated development environment called LPSolve IDE, for Microsoft Windows.
Further reading
Describes both how to use lp_solve and how to use the R bindings for it
Describes how to call lp_solve from R, S-PLUS and Microsoft Excel
References
External links
lp_solve official website
Debian package
R bindings
node.js bindings
Rust bindings
Mathematical optimization software
Free mathematics software
Free software programmed in C
Mathematics software for Linux | Lp solve | [
"Mathematics"
] | 231 | [
"Mathematics software for Linux",
"Free mathematics software",
"Mathematical software"
] |
69,397,812 | https://en.wikipedia.org/wiki/Killing%20of%20Gracie%20Spinks | Gracie Spinks was a lifeguard from Old Whittington who was murdered by a former colleague.
Background
Spinks was a swimming instructor and lifeguard but had been working as a warehouse operative at the time of her death. She was a keen horse rider and kept a horse at Blue Lodge Farm in Duckmanton.
In February 2021 she had reported a former colleague, Michael Sellers, to police for stalking. He had been her supervisor at a warehouse where she once worked.
Discovery
Gracie was last seen alive by her mother at 7:30am on 18 June 2021, when she left home to tend to her horse. She was found unconscious in the horse's field after 8am and a man was seen running away. Initially it was thought she had been kicked by the horse, but paramedics realised she had been attacked and called police. She was declared dead at 8:50am.
Sellers was found dead in a field less than a mile away, at 11am the same day.
Inquests
Separate inquests were held into the two deaths.
A post-mortem examination determined that Spinks died from a stab wound that severed an artery and her spine. There was no evidence she was sexually assaulted.
It is believed by police that Michael Sellers was responsible for her stab wounds, and that he killed himself afterwards.
Police conduct
After the incident, Derbyshire police referred itself to the Independent Office for Police Conduct due to their previous contact with Gracie. After an investigation disciplinary notices were served on five police officers.
Two were served with notices over their handling of her allegations of stalking against Michael Sellers. A sergeant and two constables were served with misconduct orders over the steps they took after discovering a bag of weapons which included a hammer, an axe and knives in May 2021 near the site where Gracie was eventually stabbed.
Her family has campaigned for "Gracie's law", which would increase funding for investigating stalking cases. Her parents said she was failed by police.
See also
List of unsolved murders in the United Kingdom
References
Crime in Derbyshire
Deaths by stabbing in England
Female murder victims
Stalking
Unsolved murders in England
Violence against women in England
Year of birth missing | Killing of Gracie Spinks | [
"Biology"
] | 438 | [
"Behavior",
"Aggression",
"Stalking"
] |
69,400,817 | https://en.wikipedia.org/wiki/Walter%20Douglas%20Hincks | Walter Douglas Hincks (3 September 1906 – 12 June 1961) was a British entomologist and museum curator. He was a world expert on the Dermaptera.
Biography
Hincks originally trained as a chemist and worked in the Pharmaceutical sector before his transition to professional entomology. He became passionate for entomology during his time as a member of the Leeds Naturalist's Club and was particularly encourage to take an interest in the Dermaptera by Malcolm Burr.
In 1941 he spent some time rearranging the coleoptera collections at the Yorkshire Museum. The following year he was appointed the Honorary Curator of Entomology (excluding the lepidoptera). During 1942 Hincks worked with A. Smith and Reginald Wagstaffe to collect entomological specimens from Askham Bog for the museum collections. He was instrumental in bringing the Ellis collection of insects to the museum in 1945.
Hincks replaced Harry Britten as Assistant Keeper at the Manchester Museum in 1947. In 1957 he was promoted to Keeper and remained in this position until his death in 1961. He, along with his technician (and eventual successor) Alan Brindle, were responsible for developing the extent and geographic scope of the Dermaptera collection at the museum.
He was president of the Manchester Entomological Society in 1952–1953. Hincks also served as the Assistant Secretary for the North Western Naturalists' Society, and was recorder of the Lancashire and Cheshire Fauna Committee. He was a member of the Yorkshire Naturalists' Union, the Microscopy Society, and the Society for British Entomology. He was a member of the Yorkshire Philosophical Society during his time in York.
Hincks published widely on the Dermaptera of the world, often in international journals, and was responsible for naming several new species of that order.
He was well known as the co-author, with G S Kloet, of "A Checklist of British Insects".
Select publications
Hincks, W.D. 1938. "Die Arthropodenfauna von Madeira nach den Ergebnissen der Reise von Prof. O. Lundblad Juli–August 1935. XI. Dermaptera", Arkiv för Zoologi' 30B(12), 1–8.
Hincks, W.D. 1940. "Dermaptera (earwigs) from Hainan Island". Notes d’Entomologie Chinoise 8(2), 29–40.
Hincks, W.D. 1947. "A new species of earwig from Sierra Leone (Dermaptera)", Entomologist 80, 201–203.
Kloet, G.S. and Hincks, W.D. 1945. A Checklist of British Insects. Stockport.
Hincks, W.D. 1954. "Obituary: Harry Britten, M.Sc., A.L.S., F.R.E.S", Journal of the society for British entomology 4, 225–228.
Hincks, W.D. 1955. A Systematic Monograph of the Dermaptera of the World. Part I. Pygidicranidae: Diplatyinae. British Museum (Natural History), London.
Hincks, W.D. 1955. "New species of pygidicranine earwigs (Dermaptera: Pygidicranidae)". Annals and Magazine of Natural History 12(8), 806–827.
Hincks, W.D. 1957. "Dermaptera". South African Animal Life 4, 33–94.
Hincks, W.D. 1959. A Systematic Monograph of the Dermaptera of the World. Part II. Pygidicranidae excluding Diplatyinae''. British Museum (Natural History), London.
References
1906 births
1961 deaths
British entomologists
Fellows of the Royal Entomological Society
Members of the Yorkshire Philosophical Society
Yorkshire Museum people
Taxon authorities
Presidents of the Entomological Society of Canada | Walter Douglas Hincks | [
"Biology"
] | 848 | [
"Taxon authorities",
"Taxonomy (biology)"
] |
69,401,249 | https://en.wikipedia.org/wiki/Acoustic%20angiography | A specific branch of contrast-enhanced ultrasound, acoustic angiography is a minimally invasive and non-ionizing medical imaging technique used to visualize vasculature. Acoustic angiography was first developed by the Dayton Laboratory at North Carolina State University and provides a safe, portable, and inexpensive alternative to the most common methods of angiography such as Magnetic Resonance Angiography and Computed Tomography Angiography. Although ultrasound does not traditionally exhibit the high resolution of MRI or CT, high-frequency ultrasound (HFU) achieves relatively high resolution by sacrificing some penetration depth. HFU typically uses waves between 20 and 100 MHz and achieves resolution of 16-80μm at depths of 3-12mm. Although HFU has exhibited adequate resolution to monitor things like tumor growth in the skin layers, on its own it lacks the depth and contrast necessary for imaging blood vessels. Acoustic angiography overcomes the weaknesses of HFU by combining contrast-enhanced ultrasound with the use of a dual-element ultrasound transducer to achieve high resolution visualization of blood vessels at relatively deep penetration levels.
Acoustic angiography is performed by first injecting specially designed microbubbles with a low resonant frequency into the vessels. Next, a low-frequency transducer element with good depth penetration is used to send ultrasound waves into the sample at the resonant frequency of the microbubbles. This will generate a response from the microbubbles consisting of subharmonic, fundamental, and super-harmonic frequencies, as well as a response from the surrounding tissue consisting of only the fundamental and second-harmonic frequencies. Finally, a high-frequency transducer with high resolution is used to measure the super-harmonic frequencies, effectively removing any background signal from the microbubble signal, and allowing the vessels to be visualized
Background
Angiography, or the examination of blood vessels, is essential in many areas of research and clinical practice. In particular, angiography is needed to monitor angiogenesis, which is the growth and development of new blood vessels. Angiogenesis is an essential process which is most often observed in organ growth in fetuses and children, the development of the placenta in adults, and wound healing. However, excessive angiogenesis has been observed in dozens of disorders, including diabetes, endometriosis, autoimmune disease, and asthma. Angiography has been used in the research, diagnosis, and treatment of many of these disorders. Perhaps the most important application of angiography for monitoring angiogenesis is in tumor growth. Tumors can exist for months or even years in a non-angiogeneic stage of development and only begin rapid growth once the angiogenic phenotype is expressed. Thus, angiogenesis has become a target for certain cancer therapies. Some therapies aim to promote organized development of blood vessels in tumor regions, which allows for more homogenous and effective distribution of chemotherapy. Other methods aim to block the start or progression of angiogenesis altogether. In both cases, angiography is essential for measuring the growth, recession, or shape of blood vessels in-vivo over time during these treatments and related research
Currently, the most common techniques used for angiography are X-ray CT and MRI. However, many other methods are used for performing angiography in special circumstances, such as the use of optical coherence tomography for performing angiography during retinal exams. MRI angiography provides the highest resolution of the current angiographic methods and can often be performed without the use of contrast agents by modifying the pulse sequence to visualize aspects of the vessels such as blood flow. On the other hand, x-ray CT angiography requires the use of a contrast agent, but still maintains relatively high resolution. Despite the high quality images produced by both of these techniques, there remain significant drawbacks. Both are relatively slow and require expensive equipment, while x-ray CT also exposes patients to potentially harmful ionizing radiation. Thus, there is still a need for an inexpensive, portable, and safe candidate for angiography. Acoustic angiography is able to fill this need. By using microbubbles as a contrast agent and a dual-element transducer for signal identification, acoustic angiography achieves depth, vessel contrast, and resolution not possible with other ultrasound techniques.
Ultrasound contrast agents
Ultrasound contrast agents are particles used in ultrasound scans to improve image contrast. The first reported use of an ultrasound contrast agent was by Dr. Raymond Gramiak and Pravin Shah in 1968, when they injected saline into the aortic root of the heart and observed increased contrast. They hypothesized that the increase in contrast was a result of "mini bubbles produced by the rapid injection rate or possibly included in the contrast medium". Although most ultrasound contrast agents take the form of microbubbles, other types exist, such as perfluorocarbon nanoparticles or echogenic liposomes.
Components
Microbubble contrast agents generally have three main components:
Inner Gas: The gas inside the microbubble is generally air or a perfluorocarbon.
Lipid Shell: This shell serves to enclose the gas within it and is always made of lipids due to their hydrophobic property
Ligands: In the case of actively targeted microbubbles, ligands are attached to the outer surface of the lipid shell. These ligands are specific to membrane receptors in the body, and can be used to target certain physiological processes (such as inflammation) or organs. In the case of passively targeted microbubbles, no ligands are attached to the outer shell, and instead the microbubbles rely on factors such as surface charge in order to adhere to the endothelium.
Mechanism of contrast
Microbubbles work as contrast agents in ultrasound for two main reasons: The large difference in acoustic impedance between body tissues and the microbubbles and their quality of having a resonant frequency generally under 10 MHz. Due to the larger mismatch in acoustic impedances, the microbubbles are near-perfect reflectors of ultrasound waves in the body. This allows them to be point-sources of acoustic waves. Furthermore, at their resonant frequency, the microbubbles have a relatively large-magnitude broadband frequency response, which is picked up by the ultrasound transducer.
Microbubble signal identification
In classical contrast-enhanced ultrasound, many methods exist for separating signal reflected by the microbubbles and signal reflected by surrounding body tissues. Most of these methods utilize the subharmonic and super harmonic response of the microbubbles, as well as the microbubbles nonlinear response to ultrasound waves, as opposed to body tissues linear response to ultrasound waves. Some of the more common filtering methods are listed below.
Subharmonic filtering: This works by filtering out all signals but the subharmonic signals. Since tissue generally does not have a subharmonic response, only the microbubble signal remains. However, since this filters for the low-frequency signals, the resolution is slightly degraded as spatial resolution in ultrasound is dependent on the acoustic frequency.
Super harmonic filtering: Similar to subharmonic filtering, this works by filtering all but the super harmonic frequencies, which are mostly emitted by the microbubbles and not surrounding tissue. Unlike subharmonic filtering, the resolution is actually improved since only the high-frequency response is received. However, most clinical transducers do not have the wide bandwidth necessary to be able to accomplish this.
Phase inversion: This filtering method utilizes the characteristically nonlinear response of the microbubbles to ultrasound waves. Here, nonlinear response means that the phase and magnitude of the acoustic wave reflected by the microbubble do not have a linear relationship with the phase and magnitude of the excitatory acoustic wave. In this method, two pulses with opposite phase are emitted by the transducer. The linear response of tissue will cause mostly destructive interference of the opposite-phased waves, while the nonlinear response of microbubbles will allow some signal to pass through.
With the creation of a dual-element transducer, these filtering methods are no longer critical. This is what distinguishes acoustic angiography from the more generic contrast-enhanced ultrasound. An element centered at a low frequency serves to excite the microbubbles at their resonant frequency, while an element centered at a high frequency receives the super harmonic response of the microbubbles. Since the tissue is excited by the low frequency input and does not produce a high frequency response, the only response received by the dual-element transducer is that originating from the microbubbles. Thus, little to no signal processing is necessary to remove tissue signal from the acquired data.
Because the inner element is receive only while the outer element is transmit only, special materials can be chosen to optimize the efficiency and sensitivity of this process. Lead Zirconate Titanate (PZT) works well as a material choice for the transmitting element because it has a high transmitting constant (d = 300 x 10^-12 m/V) while Polyvinylidene Fluoride (PVDF) works well as a material for the receiving element because it has a high receiving constant (g = 14 x 10^-2 Vm/N). Generally, PVDF is not a good choice for an ultrasound transducer because it has a relatively poor transmitting constant, however, since acoustic angiography separates the transmitting and receiving elements, this is no longer an issue.
Image formation
Data acquisition
As acoustic angiography uses a dual-element ultrasonic transducer in the format of a focused ultrasound probe, it is not feasible to form an array of transducers as can be done in other forms of ultrasound imagining. Thus acoustic angiography images are formed by combining multiple a-mode images where each a-mode is a one-dimensional image identifying the acoustic boundaries along a vector originating at the transducer.
In order to form two or three dimensional images, the position and angle of the transducer and the resulting a-mode image must be mechanically manipulated. Two common configurations used to acquire these a-mode images include the wobbler configuration and mechanical sweep configuration.
In the wobbler configuration, the probe is rotated back and forth about a central axis in one plane so that the a-scans are radially oriented and the field of view, or region that is able to be imaged, is a cone. This allows for very quick acquisition of a-scans, but has nonhomogeneous resolution as the distance between each point on neighboring a-scans increases with depth.
In the linear sweep configuration, the ultrasound probe is mechanically moved, either by an external mechanism or hand, in a direction orthogonal to the direction of the a-scan. This configuration allows relatively consistent resolution as a function of depth as each point on neighboring a-scans is equidistant.
Once data has been collected as described above, it can be processed to form a variety of image types including projections and volumetric reconstruction.
Projection
Projection images in ultrasound are similar in concept to projection radiography. However, instead of projecting the degree of absorbance of X-ray photons along a given path, projection images in ultrasound generally project the mismatch of acoustic impedance and the location along a given boundary in tissue.
Maximum amplitude projection
The maximum amplitude projection or the maximum intensity projection is an image processing technique used to project three dimensional data onto a two dimensional image. This is a valuable tool as it allows the complex data to be formed into more readily understandable images that include the perception of depth.
In many forms of ultrasound imaging and photoacoustic imaging, the maximum amplitude of the signal along a given a-scan is used as the value for a pixel associated with that a-scan. As acoustic wave experience distance-dependent acoustic attenuation, the amplitude of a given signal along a given a-scan also encodes the distance to the object that generated that signal.
This simple image reconstruction technique allows for easily formed and interpretable projection images formed from acoustic signals.
Volumetric renderings
Volumetric renderings convert volumetric data into projection images. Most methods use data acquired in lower dimensions to generate voxels, volumetric pixels, that can form 3D images when combined.
Volumetric reconstruction
Volume reconstruction techniques are used to convert multiple 1D or 2D images into 3D volumes. Common volume reconstruction techniques include pixel-nearest-neighbors, voxel-nearest-neighbors, distance-weighted voxels, and function based methods used to statistically infer the value of a given voxel.
Applications
As acoustic angiography is currently under development, this specific branch of contrast-enhanced ultrasound is not currently used in clinical settings. The majority of the previous work using acoustic angiography has studied angiogenesis in animal models for research purposes.
Though the FDA has only approved contrast-enhanced ultrasound use in one clinical application in the United States, echocardiography, the broader technique has been used throughout Europe and Asia to great success in a variety of clinical applications. To learn more, see the current applications of contrast enhanced ultrasound.
Currently investigated clinical uses
The only use of acoustic angiography that has been investigated in clinical settings to date studied angiogenesis in the peripheral vasculature of human breast tissue. This study investigated if acoustic angiography could be used to reduce the need for biopsy of breast tissue when diagnosing if lesions in breast tissue were cancerous or not.
Using acoustic angiography, the authors collected and reconstructed the 3D volumes associated with vasculature surrounding lesions in the breast. These reconstructed volumes were then analyzed for vascular density and tortuosity. This information is useful for diagnosis as it has been shown that when these two factors increase in the vasculature surrounding a lesion, there is an increased risk that the lesion is cancerous.
References
Acoustics
Medical ultrasonography | Acoustic angiography | [
"Physics"
] | 2,852 | [
"Classical mechanics",
"Acoustics"
] |
69,402,060 | https://en.wikipedia.org/wiki/Prenylthiol | Prenylthiol or 3-methyl-2-butene-1-thiol is a chemical compound. It is one of a group of chemicals that give cannabis its characteristic "skunk-like" aroma. It is also present in lightstruck or "skunky" beer.
References
Thiols | Prenylthiol | [
"Chemistry"
] | 66 | [
"Organic compounds",
"Thiols",
"Organic compound stubs",
"Organic chemistry stubs"
] |
69,402,710 | https://en.wikipedia.org/wiki/Colletotrichum%20fioriniae | Colletotrichum fioriniae is a fungal plant pathogen and endophyte of fruits and foliage of many broadleaved plants worldwide. It causes diseases on agriculturally important crops, including anthracnose of strawberry, ripe rot of grapes, bitter rot of apple, anthracnose of peach, and anthracnose of blueberry. Its ecological role in the natural environment is less well understood, other than it is a common leaf endophyte of many temperate trees and shrubs and in some cases may function as an entomopathogen.
Taxonomic history
C. fioriniae was formally described as a variety of Colletotrichum acutatum in 2008, and as its own species shortly thereafter. However, while it had not previously been recognized as a separate species, when grown on potato dextrose agar it produces a distinct pink to maroon red color on the bottom side and was described in historical studies as "chromogenic" isolates of Glomerella cingulata. It is currently recognized as a species within the C. acutatum species complex.
Identification
C. fioriniae produces conidia that are smooth-walled, hyaline (glassy and translucent), with acute (pointed) ends, measuring about 15 x 4.5 microns. When grown on potato dextrose agar it usually produces a pink to dark red chromogenic color on the reverse side. However, these morphological characteristic overlap with those of other species in the C. acutatum species complex, so definitive identification requires the sequencing of DNA barcoding regions such as the internally transcribed spacer (ITS), or introns in the GAPDH, histone3, beta-tubulin, or actin genes.
Reproduction
Like other species in the C. acutatum species complex, C. fioriniae reproduces almost exclusively via the production of asexual spores called conidia. These conidia are often produced in sticky gelatinous orange masses that are rain-splash dispersed. Conidia are mostly produced at temperatures from 10 to 30 °C, such that in temperate deciduous forests and orchards rain-splash dispersal occurs from bud-break to leaf drop.
Pathogenic lifestyle
As a plant pathogen, C. fioriniae has a hemibiotrophic lifestyle, where infections are initially biotrophic (or latent or quiescent, depending on the point of view) before switching to necrotrophy and active killing of the plant cells.
References
Further reading
Suppl. T 1 & 2 Taxonomy, taxonomic IDs, 14 predicted proteins:
Colletotrichum
Fungus species | Colletotrichum fioriniae | [
"Biology"
] | 541 | [
"Fungi",
"Fungus species"
] |
61,494,961 | https://en.wikipedia.org/wiki/NGC%204306 | NGC 4306 is a dwarf barred lenticular galaxy located about 100 million light-years away in the constellation Virgo. The galaxy was discovered by astronomer Heinrich d'Arrest on April 16, 1865. Although considered to be a member of the Virgo Cluster, its high radial velocity and similar distance as NGC 4305 suggest that NGC 4306 is a background galaxy. NGC 4306 is a companion of NGC 4305 and appears to be interacting with it.
References
External links
4306
040032
Virgo (constellation)
Astronomical objects discovered in 1865
Dwarf galaxies
07433
Virgo Supercluster
Interacting galaxies
Barred lenticular galaxies | NGC 4306 | [
"Astronomy"
] | 128 | [
"Virgo (constellation)",
"Constellations"
] |
61,495,237 | https://en.wikipedia.org/wiki/Software%20testing%20certification%20board | A software testing certification board is an organization that provides professional certification for software testing and software quality assurance.
Notable boards
British Computer Society
The British Computer Society (BCS) is a British learned society that offers software testing certification. Since 2012, its professional software testing certification has been the successor to Systems Analysis Examination Board (SAEB) and the Information Systems Examination Board (ISEB).
International Software Certification Board
The International Software Certification Board (ISCB) is an international software testing board, affiliated with the Quality Assurance Institute (QAI). The ISCB was founded in 1980. Since 1985, it has offered the Certified Software Quality Analyst (CSQA) certification, originally called Certified Quality Analyst (CQA).
International Software Testing Qualifications Board
The International Software Testing Qualifications Board (ISTQB) is an international software testing board, founded in 2002.
The ISTQB has 66 member boards, including the American Software Testing Qualifications Board (ASTQB), the Australia and New Zealand Testing Board (ANZTB), the Czech and Slovak Testing Board (CaSTB), and the Sri Lanka Software Testing Board (SLSTB).
References
External links
ISCB official site
ISTQB official site
Software testing | Software testing certification board | [
"Engineering"
] | 246 | [
"Software engineering",
"Software testing"
] |
61,495,667 | https://en.wikipedia.org/wiki/C6334H9792N1700O2000S42 | {{DISPLAYTITLE:C6334H9792N1700O2000S42}}
The molecular formula C6334H9792N1700O2000S42 (molar mass: 143.1 kg/mol) may refer to:
Drozitumab
Enavatuzumab
Molecular formulas | C6334H9792N1700O2000S42 | [
"Physics",
"Chemistry"
] | 75 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,495,678 | https://en.wikipedia.org/wiki/C18H24O | {{DISPLAYTITLE:C18H24O}}
The molecular formula C18H24O (molar mass: 256.39 g/mol, exact mass: 256.1827 u) may refer to:
Bakuchiol
Drupanol | C18H24O | [
"Chemistry"
] | 55 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,495,684 | https://en.wikipedia.org/wiki/C24H29FO4 | {{DISPLAYTITLE:C24H29FO4}}
The molecular formula C24H29FO4 (molar mass: 400.49 g/mol) may refer to:
DU-41164
DU-41165, or 6-fluoro-16-methylene-17α-acetoxy-δ6-retroprogesterone
Molecular formulas | C24H29FO4 | [
"Physics",
"Chemistry"
] | 79 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,495,693 | https://en.wikipedia.org/wiki/C12H18N4O4 | {{DISPLAYTITLE:C12H18N4O4}}
The molecular formula C12H18N4O4 (molar mass: 282.30 g/mol, exact mass: 282.1328 u) may refer to:
Dupracetam
ICRF 193 | C12H18N4O4 | [
"Chemistry"
] | 62 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,495,703 | https://en.wikipedia.org/wiki/C21H27N3O3S | {{DISPLAYTITLE:C21H27N3O3S}}
The molecular formula C21H27N3O3S (molar mass: 401.52 g/mol) may refer to:
E-4031
Sonepiprazole (U-101,387, PNU-101,387-G)
Molecular formulas | C21H27N3O3S | [
"Physics",
"Chemistry"
] | 77 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,495,719 | https://en.wikipedia.org/wiki/C9H22NO2PS | {{DISPLAYTITLE:C9H22NO2PS}}
The molecular formula C9H22NO2PS (molar mass: 239.31 g/mol, exact mass: 239.1109 u) may refer to:
EA-2192
VM (nerve agent) | C9H22NO2PS | [
"Chemistry"
] | 63 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,495,967 | https://en.wikipedia.org/wiki/C18H22N4O2 | {{DISPLAYTITLE:C18H22N4O2}}
The molecular formula C18H22N4O2 (molar mass: 326.17 g/mol, exact mass: 326.1743 u) may refer to:
EGIS-7625
Peficitinib (Smyraf) | C18H22N4O2 | [
"Chemistry"
] | 69 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,496,154 | https://en.wikipedia.org/wiki/C23H22FN3O | {{DISPLAYTITLE:C23H22FN3O}}
The molecular formula C23H22FN3O (molar mass: 375.44 g/mol, exact mass: 375.1747 u) may refer to:
Elopiprazole
5F-PCN, also called 5F-MN-21 | C23H22FN3O | [
"Chemistry"
] | 73 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,496,833 | https://en.wikipedia.org/wiki/C25H43N13O10 | {{DISPLAYTITLE:C25H43N13O10}}
The molecular formula C25H43N13O10 (molar mass: 685.69 g/mol, exact mass: 685.3256 u) may refer to:
Enviomycin
Viomycin
Molecular formulas | C25H43N13O10 | [
"Physics",
"Chemistry"
] | 66 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,497,626 | https://en.wikipedia.org/wiki/1%2C3-Bis%28aminomethyl%29cyclohexane | 1,3-bis(aminomethyl)cyclohexane (1,3-BAC) are a collection of organic compounds with the formula . The compounds belong to the sub class cycloaliphatic amine. Their key use is as an epoxy resin curing agent.
Manufacture
It has been produced commercially as part of a mixture with the 1,4 derivative. The primary route of manufacture is by catalytic hydrogenation of m-xylylenediamine usually called MXDA.
Uses
Like most amines it maybe used as an epoxy curing agent. However, the presence of the amino group also means it can be used in polyurethane chemistry by reacting with isocyanates. In this case a polyurea would be produced. It may also be reacted with phosgene (phosgenation) to produce an isocyanate.
Safety
It is corrosive with a Packing Group I designation.
See also
Epoxy
IPDA
MXDA
PACM
DCH-99
References
Amines
Cycloalkylamines
Diamines | 1,3-Bis(aminomethyl)cyclohexane | [
"Chemistry"
] | 228 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
61,498,603 | https://en.wikipedia.org/wiki/C20H21F3N2O2 | {{DISPLAYTITLE:C20H21F3N2O2}}
The molecular formula C20H21F3N2O2 (molar mass: 378.387 g/mol) may refer to:
EPPTB
Tilapertin
Molecular formulas | C20H21F3N2O2 | [
"Physics",
"Chemistry"
] | 61 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,498,787 | https://en.wikipedia.org/wiki/C17H19N3O3S | {{DISPLAYTITLE:C17H19N3O3S}}
The molecular formula C17H19N3O3S (molar mass: 345.417 g/mol, exact mass: 345.1147 u) may refer to:
Esomeprazole
Omeprazole
Molecular formulas | C17H19N3O3S | [
"Physics",
"Chemistry"
] | 68 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,498,873 | https://en.wikipedia.org/wiki/C25H34O3 | {{DISPLAYTITLE:C25H34O3}}
The molecular formula C25H34O3 (molar mass: 382.544 g/mol) may refer to:
Estradiol hexahydrobenzoate
Levonorgestrel butanoate
Trenbolone enanthate
Molecular formulas | C25H34O3 | [
"Physics",
"Chemistry"
] | 71 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,498,907 | https://en.wikipedia.org/wiki/C13H21N5O2 | {{DISPLAYTITLE:C13H21N5O2}}
The molecular formula C13H21N5O2 (molar mass: 279.34 g/mol, exact mass: 279.1695 u) may refer to:
Etamiphylline
Tezampanel | C13H21N5O2 | [
"Chemistry"
] | 63 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,498,989 | https://en.wikipedia.org/wiki/Hexagonal%20architecture%20%28software%29 | The hexagonal architecture, or ports and adapters architecture, is an architectural pattern used in software design. It aims at creating loosely coupled application components that can be easily connected to their software environment by means of ports and adapters. This makes components exchangeable at any level and facilitates test automation.
Origin
The hexagonal architecture was invented by Alistair Cockburn in an attempt to avoid known structural pitfalls in object-oriented software design, such as undesired dependencies between layers and contamination of user interface code with business logic. It was discussed at first on the Portland Pattern Repository wiki; in 2005 Cockburn renamed it "Ports and adapters". In April 2024, Cockburn published a comprehensive book on the subject, coauthored with Juan Manuel Garrido de Paz.
The term "hexagonal" comes from the graphical conventions that shows the application component like a hexagonal cell. The purpose was not to suggest that there would be six borders/ports, but to leave enough space to represent the different interfaces needed between the component and the external world.
Principle
The hexagonal architecture divides a system into several loosely-coupled interchangeable components, such as the application core, the database, the user interface, test scripts and interfaces with other systems. This approach is an alternative to the traditional layered architecture.
Each component is connected to the others through a number of exposed "ports". Communication through these ports follow a given protocol depending on their purpose. Ports and protocols define an abstract API that can be implemented by any suitable technical means (e.g. method invocation in an object-oriented language, remote procedure calls, or Web services).
The granularity of the ports and their number is not constrained:
a single port could in some case be sufficient (e.g. in the case of a simple service consumer);
typically, there are ports for event sources (user interface, automatic feeding), notifications (outgoing notifications), database (in order to interface the component with any suitable DBMS), and administration (for controlling the component);
in an extreme case, there could be a different port for every use case, if needed.
Adapters are the glue between components and the outside world. They tailor the exchanges between the external world and the ports that represent the requirements of the inside of the application component. There can be several adapters for one port, for example, data can be provided by a user through a GUI or a command-line interface, by an automated data source, or by test scripts.
Criticism
The term "hexagonal" implies that there are 6 parts to the concept, whereas there are only 4 key areas. The term’s usage comes from the graphical conventions that shows the application component like a hexagonal cell. The purpose was not to suggest that there would be six borders/ports, but to leave enough space to represent the different interfaces needed between the component and the external world.
According to Martin Fowler, the hexagonal architecture has the benefit of using similarities between presentation layer and data source layer to create symmetric components made of a core surrounded by interfaces, but with the drawback of hiding the inherent asymmetry between a service provider and a service consumer that would better be represented as layers.
Evolution
According to some authors, the hexagonal architecture is at the origin of the microservices architecture.
Variants
The onion architecture proposed by Jeffrey Palermo in 2008 is similar to the hexagonal architecture: it also externalizes the infrastructure with interfaces to ensure loose coupling between the application and the database. It decomposes further the application core into several concentric rings using inversion of control.
The clean architecture proposed by Robert C. Martin in 2012 combines the principles of the hexagonal architecture, the onion architecture and several other variants. It provides additional levels of detail of the component, which are presented as concentric rings. It isolates adapters and interfaces (user interface, databases, external systems, devices) in the outer rings of the architecture and leaves the inner rings for use cases and entities. The clean architecture uses the principle of dependency inversion with the strict rule that dependencies shall only exist between an outer ring to an inner ring and never the contrary.
See also
Architecture patterns
Cell-based architecture
Layer (object-oriented design)
Composite structure diagram
Object oriented analysis and design
References
Software design
Architectural pattern (computer science)
Object-oriented programming | Hexagonal architecture (software) | [
"Engineering"
] | 895 | [
"Design",
"Software design"
] |
61,500,844 | https://en.wikipedia.org/wiki/C17H16N2O | {{DISPLAYTITLE:C17H16N2O}}
The molecular formula C17H16N2O (molar mass: 264.322 g/mol, exact mass: 264.1263 u) may refer to:
Etaqualone
Methylmethaqualone (MMQ)
Molecular formulas | C17H16N2O | [
"Physics",
"Chemistry"
] | 67 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,501,485 | https://en.wikipedia.org/wiki/Port%20Colborne%20explosion | The Port Colborne explosion at Port Colborne, Ontario was a dust explosion in the Dominion grain elevator on August 9, 1919. The blast killed 10 and seriously injured 16 more.
Background
A dust explosion is the rapid combustion of fine particles suspended in the air within an enclosed location. Dust explosions can occur where any dispersed powdered combustible material is present in high-enough concentrations in the atmosphere or other oxidizing gaseous medium, such as pure oxygen. Dust explosions are a frequent hazard in coal mines, grain elevators, and other industrial environments. The Port Colborne explosion was just one of five that occurred in North America between May 20 to September 13, 1919, due to a lack of regulations concerning grain shipment. The series of dust explosions resulted in 70 deaths and many more injuries.
Explosion
Servicing the grain exports of Canada the concrete structure that had a capacity of was completely destroyed as well as the steamer Quebec which was berthed next to the elevator. The explosion sent flames hundreds of feet in the air and debris was blown away.
See also
Bibliography
Notes
References
1919 disasters in Canada
1919 industrial disasters
Disasters in Ontario
Dust explosions
Explosions in 1919
Food processing disasters
Industrial fires and explosions in Canada
Port Colborne
20th-century fires in Canada
1910s fires in North America
1919 fires | Port Colborne explosion | [
"Chemistry"
] | 255 | [
"Dust explosions",
"Explosions"
] |
61,501,584 | https://en.wikipedia.org/wiki/C21H27N3O | {{DISPLAYTITLE:C21H27N3O}}
The molecular formula C21H27N3O (molar mass: 337.47 g/mol) may refer to:
ETH-LAD
Lysergic acid 3-pentyl amide
N1-Methyl-lysergic acid diethylamide
Molecular formulas | C21H27N3O | [
"Physics",
"Chemistry"
] | 76 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,501,594 | https://en.wikipedia.org/wiki/C12H15NO4 | {{DISPLAYTITLE:C12H15NO4}}
The molecular formula C12H15NO4 (molar mass: 237.25 g/mol, exact mass: 237.1001 u) may refer to:
O,O′-Diacetyldopamine
Ethopabate
5-Methoxymethylone (2-A1MP)
N-lactoyl-phenylalanine (Lac-Phe) | C12H15NO4 | [
"Chemistry"
] | 97 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,502,277 | https://en.wikipedia.org/wiki/Coate%E2%80%93Loury%20model | The Coate–Loury model of affirmative action was developed by Stephen Coate and Glenn Loury in 1993. The model seeks to answer the question of whether, by mandating expanded opportunities for minorities in the present, these policies are rendered unnecessary in the future. Affirmative action may lead to one of two outcomes:
By improving employers’ perceptions of minorities or improving minorities’ skills, or both, affirmative action policies would eventually cause employers to want to hire minorities regardless of the presence of affirmative action policies.
By dampening incentives for minorities, affirmative action policies would reduce minority skill investment, thus leading to an equilibrium where employers correctly believe minorities to be less productive than majorities, thus perpetuating the need for affirmative action in order to achieve parity in the labor market.
Coate and Loury concluded that either equilibrium is possible under certain assumptions.
Model framework
The exposition of the Coate–Loury model follows the notes of David Autor. The authors make three assumptions as a starting point for their model:
The underlying skill distributions of minorities and non-minorities are the same. This skill distribution is modeled as a distribution of costs of obtaining a qualification.
Employers cannot observe qualifications but do observe noisy signals that are correlated with it.
Employers have rational expectations about worker qualifications and workers have rational expectations about employer screening. Thus, in equilibrium, employers beliefs about worker qualifications will be confirmed. And, similarly, workers will make investments consistent with the returns they will receive in the labor market for those investments.
Employers are able to observe worker's identity , where the fraction of the population that is is , and a noisy signal of the worker's qualification level . Employers can assign workers to either Task 0 or Task 1, with only qualified workers being successful at Task 1. Employers get a net return from assigning a worker to Task 1 of the form:The ratio of net gain to loss .
The distribution of depends on whether or not the worker is qualified, which is assumed to not differ between and . Let be the probability that the signal does not exceed , given that the worker is qualified; is the probability that the signal does not exceed , given that the worker is unqualified. The corresponding probability density functions are and . Let be the likelihood ratio, and assume that it is non-increasing on . This implies that:Therefore, higher values of the signal are more likely if the worker is qualified. This implies that has the monotone likelihood ratio (MLR) property.
Employers' decision rule
For a worker from group or , the fraction of qualified workers in the group is . Using Bayes' rule, the employer’s posterior probability that the worker is qualified, given the worker’s signal, is:
The expected benefit of assigning a worker to Task 1 is:Then the employer will assign a worker to Task 1 if the return is positive, which implies that:Based on the MLR assumption, there exists a threshold standard that depends on group membership, so that workers with are placed in Task 1:This implies that a higher qualification rate of a group will lead to a lower threshold hiring standard .
Workers' investment decision
The expected gross benefit to obtaining appropriate qualification for a worker is:where is gross benefit of being assigned to Task 1 and is the passing standard. Given the assumption that employers have rational expectations, only the true probability that a worker is qualified should matter - not the employer's beliefs about the probability.
Note that is a single-peaked function with , since there would be no point to investing if all workers were assigned to Task 1 or no workers were assigned to Task 1. This implies that the gross benefit to investing will rise so long as the marginal probability of being assigned to Task 1 is increasing in . To see this, note that the derivative of the gross benefit with respect to is:This is only positive if . Since the boundary points are equal to zero, it follows that must sometimes be above 1 and sometimes below 1 in the interval.
Workers will invest if , so the share of workers investing will be . If is continuous and , it will have the property that when the gross benefit is rising in , the net benefit should also be rising.
Equilibrium
An equilibrium is a fixed point of the aforementioned hiring and investment policies where beliefs are self-confirming, such that:A discriminatory equilibrium can occur whenever the equilibrium equation has multiple solutions. In this case, it is possible that employers will believe that members of are less qualified than members of , which will be confirmed by the investment behavior of members of .
Proposition 1 (p. 1226) proves that, under reasonable conditions, if a solution exists to the equilibrium condition, then at least two solutions will exist. At this point, there are several observations that can be made:
Group identity conveys information only because employers expect it to.
Stereotypes are inefficient sources of information.
No single employer could break the discriminatory equilibrium.
The employer's expected benefit from hiring a worker exceeds that of hiring a worker.
Affirmative action
Under the assumption that a discriminatory equilibrium exists, with the further assumption of no differences in skill distributions, an affirmative action policy can be easily rationalized. Coate and Loury consider the policy where the rate of assignment for and workers to Task 1 is equalized. Let be the proportion of in the population.
Let be the ex ante probability that a worker is assigned to Task 1:And let be the expected payoff from hiring this worker:Under affirmative action, the employers' optimization problem is to solve:where the equality constraint on the ex ante probabilities is the affirmative action constraint. The equivalent Lagrangian is:where is the Lagrange multiplier. Proposition 2 (p. 1229) develops a condition for the existence of a nondiscriminatory equilibrium under affirmative action. In particular, if any group of workers facing standard invest so that the fraction is qualified, then all equilibria are self-confirming:In this case, the affirmative action policy would equate employers' beliefs about members of each group.
Patronizing equilibrium
However, it is not in general true that affirmative action under the model's assumptions leads to the nondiscriminatory equilibrium. If at the employer lowered the threshold , then the fraction of workers investing would fall, and the employers' beliefs about the fraction who are qualified would not be satisfied. Therefore, a policy that lowered would not be self-enforcing.
Coate and Loury define an equilibrium where affirmative action constraint is permanently binding as a patronizing equilibrium, where employers are compelled to lower their hiring standards for members of , relative to a member of . Therefore, the following conditions hold in a patronizing equilibrium:There are several possible negative effects on members of from being trapped in a patronizing equilibrium:
Due to a lower standard, members of find it optimal to invest less in skills acquisition, which then confirms employers' negative views
Despite being initially identical, reduced investment leads to a divergence between groups and the development of a negative stereotype
Recalling the Lagrangian that was developed earlier, we may consider the first-order optimality conditions. Computing and rearranging terms gives us:where the ratios of net gain to loss for each group are:Given a shadow price of equality , employers act as if they must pay the tax of for each assigned to Task 1 instead of Task 0, while receiving the subsidy for each put into Task 1 rather than Task 0. Therefore, employers generally respond to the affirmative action constraint by lowering the standard for and raising it for .
Proposition 4 (p. 1234) shows that, under reasonable assumptions, the marginal productivity of and hires is not equated.
See also
Labour economics
Law and economics
Mathematical economics
Statistical discrimination (economics)
References
Further reading
Fryer Jr., Roland G.; Loury, Glenn C. (2005). "Affirmative Action and Its Mythology". Journal of Economic Perspectives 19 (3): 147-162.
Affirmative action
Labour economics
Law and economics
Mathematical economics | Coate–Loury model | [
"Mathematics"
] | 1,622 | [
"Applied mathematics",
"Mathematical economics"
] |
61,503,305 | https://en.wikipedia.org/wiki/C27H31NO5 | {{DISPLAYTITLE:C27H31NO5}}
The molecular formula C27H31NO5 (molar mass: 449.55 g/mol) may refer to:
Ignavine
Yaequinolone J1 | C27H31NO5 | [
"Chemistry"
] | 53 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,503,405 | https://en.wikipedia.org/wiki/Watergen | Watergen Inc. (formerly Water-Gen) is an Israel-based global company that develops atmospheric water generator (AWG) systems. Its systems generate water from air at 250 Wh per liter.
History
Watergen was founded in 2009 by entrepreneur and former military commander Arye Kohavi and a team of engineers with the goal of providing freely accessible water to troops around the world.
Following the acquisition of Watergen by billionaire Michael Mirilashvili, in 2016, the company turned its attention to addressing water scarcity and responding to the needs of people in the aftermath of natural catastrophes.
Since then, Watergen has created a series of products that are appropriate for a variety of applications, ranging from remote rural locations to commercial office complexes. and private homes. It has been used around the world by armies as well as the public and private sectors in the United States, Latin America, India, Vietnam, Uzbekistan and the African continent.
The company's headquarters are in Petah Tikva. It has a subsidiary in the United States.
In May 2020, the company installed a water-from-air device at the Al-Rantisi Hospital in Gaza. This initiative, a result of a collaboration with the Palestinian power company Mayet Al Ahel, aimed to provide clean and safe off-grid drinking water for the pediatric hospital's staff and patients. The project, led by Mirilashvili, intended to address water scarcity in the Gaza Strip.
References
External links
Official Website
Israeli companies established in 2009
Israeli inventions
Water industry | Watergen | [
"Environmental_science"
] | 313 | [
"Hydrology",
"Water industry"
] |
61,503,585 | https://en.wikipedia.org/wiki/Greenhouse%20gas%20emissions%20from%20agriculture | The amount of greenhouse gas emissions from agriculture is significant: The agriculture, forestry and land use sectors contribute between 13% and 21% of global greenhouse gas emissions. Emissions come from direct greenhouse gas emissions (for example from rice production and livestock farming). And from indirect emissions. With regards to direct emissions, nitrous oxide and methane makeup over half of total greenhouse gas emissions from agriculture. Indirect emissions on the other hand come from the conversion of non-agricultural land such as forests into agricultural land. Furthermore, there is also fossil fuel consumption for transport and fertilizer production. For example, the manufacture and use of nitrogen fertilizer contributes around 5% of all global greenhouse gas emissions. Livestock farming is a major source of greenhouse gas emissions. At the same time, livestock farming is affected by climate change.
Farm animals' digestive systems can be put into two categories: monogastric and ruminant. Ruminant cattle for beef and dairy rank high in greenhouse gas emissions. In comparison, monogastric, or pigs and poultry-related foods, are lower. The consumption of the monogastric types may yield less emissions. Monogastric animals have a higher feed-conversion efficiency and also do not produce as much methane. Non-ruminant livestock, such as poultry, emit far fewer greenhouse gases.
There are many strategies to reduce greenhouse gas emissions from agriculture (this is one of the goals of climate-smart agriculture). Mitigation measures in the food system can be divided into four categories. These are demand-side changes, ecosystem protections, mitigation on farms, and mitigation in supply chains. On the demand side, limiting food waste is an effective way to reduce food emissions. Changes to a diet less reliant on animal products such as plant-based diets are also effective. This could include milk substitutes and meat alternatives. Several methods are also under investigation to reduce the greenhouse gas emissions from livestock farming. These include genetic selection, introduction of methanotrophic bacteria into the rumen, vaccines, feeds, diet modification and grazing management.
Global estimates
Total emissions from agrifood systems in 2022 amounted to 16.2 billion tonnes of carbon dioxide equivalent (Gt CO2eq) of GHG released into the atmosphere, an increase of 10%, or 1.5 Gt CO2eq compared with 2000.
In 2020, it was estimated that the food system as a whole contributed 37% of total greenhouse gas emissions and that this figure was on course to increase by 30–40% by 2050 due to population growth and dietary change.
Between 2010 and 2019, agriculture, forestry and land use contributed between 13% and 21% to global greenhouse gas emissions. Nitrous oxide and methane make up over half of total greenhouse gas emissions from agriculture.
Older estimates
In 2010, agriculture, forestry and land-use change were estimated to contribute 20–25% of global annual emissions.
Emissions by type of activity
Land use changes
Agriculture contributes to greenhouse gas increases through land use in four main ways:
CO2 releases linked to deforestation
Methane releases from rice cultivation
Methane releases from enteric fermentation in cattle
Nitrous oxide releases from fertilizer application
Together, these agricultural processes comprise 54% of methane emissions, roughly 80% of nitrous oxide emissions, and virtually all carbon dioxide emissions tied to land use.
Land cover has changed majorly since 1750, as humans have deforested temperate regions. When forests and woodlands are cleared to make room for fields and pastures, the albedo of the affected area increases, which can result in either warming or cooling effects depending on local conditions. Deforestation also affects regional carbon reuptake, which can result in increased concentrations of CO2, the dominant greenhouse gas. Land-clearing methods such as slash and burn compound these effects, as the burning of biomatter directly releases greenhouse gases and particulate matter such as soot into the air. Land clearing can destroy the soil carbon sponge.
Livestock
Livestock produces the majority of greenhouse gas emissions from agriculture and demands around 30% of agricultural freshwater needs, while only supplying 18% of the global calorie intake. Animal-derived food plays a larger role in meeting human protein needs, yet is still a minority of supply at 39%, with crops providing the rest.
Out of the Shared Socioeconomic Pathways used by the Intergovernmental Panel on Climate Change, only SSP1 offers any realistic possibility of meeting the target. Together with measures like a massive deployment of green technology, this pathway assumes animal-derived food will play a lower role in global diets relative to now. As a result, there have been calls for phasing out subsidies currently offered to livestock farmers in many places worldwide, and net zero transition plans now involve limits on total livestock headcounts, including substantial reductions of existing stocks in some countries with extensive animal agriculture sectors like Ireland. Yet, an outright end to human consumption of meat and/or animal products is not currently considered a realistic goal. Therefore, any comprehensive plan of adaptation to the effects of climate change, particularly the present and future effects of climate change on agriculture, must also consider livestock.
Livestock activities also contribute disproportionately to land-use effects, since crops such as corn and alfalfa are cultivated to feed the animals.
In 2010, enteric fermentation accounted for 43% of the total greenhouse gas emissions from all agricultural activity in the world. The meat from ruminants has a higher carbon equivalent footprint than other meats or vegetarian sources of protein based on a global meta-analysis of lifecycle assessment studies. Small ruminants such as sheep and goats contribute approximately 475 million tons of carbon dioxide equivalent to GHG emissions, which constitutes around 6.5% of world agriculture sector emissions. Methane production by animals, principally ruminants, makes up an estimated 15-20% of global production of methane.
Worldwide, livestock production occupies 70% of all land used for agriculture or 30% of the land surface of the Earth. The global food system is responsible for one-third of the global anthropogenic GHG emissions, of which meat accounts for nearly 60%.
Cows, sheep and other ruminants digest their food by enteric fermentation, and their burps are the main methane emissions from land use, land-use change, and forestry: together with methane and nitrous oxide from manure, this makes livestock the main source of greenhouse gas emissions from agriculture.
The IPCC Sixth Assessment Report in 2022 stated that: "Diets high in plant protein and low in meat and dairy are associated with lower GHG emissions. [...] Where appropriate, a shift to diets with a higher share of plant protein, moderate intake of animal-source foods and reduced intake of saturated fats could lead to substantial decreases in GHG emissions. Benefits would also include reduced land occupation and nutrient losses to the surrounding environment, while at the same time providing health benefits and reducing mortality from diet-related non-communicable diseases."According to a 2022 study quickly stopping animal agriculture would provide half the GHG emission reduction needed to meet the Paris Agreement goal of limiting global warming to 2 °C. There are calls to phase out livestock subsidies as part of a just transition.
In the context of global GHG emissions, food production within the global food system accounts for approximately 26%. Breaking it down, livestock and fisheries contribute 31%, whereas crop production, land use, and supply chains add 27%, 24%, and 18% respectively to the emissions.
A 2023 study found that a vegan diet reduced emissions by 75%.
Research in New Zealand estimated that switching agricultural production towards a healthier diet while reducing greenhouse gas emissions would cost approximately 1% of the agricultural sector's export revenue for New Zealand, which is an order of magnitude less than the estimated health system savings from a healthier diet.
Research continues on the use of various seaweed species, in particular Asparegopsis armata, as a food additive that helps reduce methane production in ruminants.
Fertilizer production
Crop growth
is re-emitted into the atmosphere by plant and soil respiration in the later stages of crop growth, causing more greenhouse gas emissions.
Rice production
Emissions by type of greenhouse gas
Agricultural activities emit the greenhouse gases carbon dioxide, methane and nitrous oxide.
Carbon dioxide emissions
Activities such as tilling of fields, planting of crops, and shipment of products cause carbon dioxide emissions. Agriculture-related emissions of carbon dioxide account for around 11% of global greenhouse gas emissions. Farm practices such as reducing tillage, decreasing empty land, returning biomass residue of crops to the soil, and increasing the use of cover crops can reduce carbon emissions.
Methane emissions
Methane emissions from livestock are the number one contributor to agricultural greenhouse gases globally. Livestock are responsible for 14.5% of total anthropogenic greenhouse gas emissions. One cow alone will emit 220 pounds of methane per year. While the residence time of methane is much shorter than that of carbon dioxide, it is 28 times more capable of trapping heat. Not only do livestock contribute to harmful emissions, but they also require a lot of land and may overgraze, which leads to unhealthy soil quality and reduced species diversity. A few ways to reduce methane emissions include switching to plant-rich diets with less meat, feeding the cattle more nutritious food, manure management, and composting.
Traditional rice cultivation is the second biggest agricultural methane source after livestock, with a near-term warming impact equivalent to the carbon dioxide emissions from all aviation. Government involvement in agricultural policy is limited due to the high demand for agricultural products like corn, wheat, and milk. The United States Agency for International Development's (USAID) global hunger and food security initiative, the Feed the Future project, is addressing food loss and waste. By addressing food loss and waste, greenhouse gas emission mitigation is also addressed. By only focusing on dairy systems of 20 value chains in 12 countries, food loss and waste could be reduced by 4-10%. These numbers are impactful and would mitigate greenhouse gas emissions while still feeding the population.
Nitrous oxide emissions
Nitrous oxide emission comes from the increased use of synthetic and organic fertilizers. Fertilizers increase crop yield production and allow the crops to grow at a faster rate. Agricultural emissions of nitrous oxide make up 6% of the United States' greenhouse gas emissions; they have increased in concentration by 30% since 1980. While 6% may appear to be a small contribution, nitrous oxide is 300 times more effective at trapping heat per pound than carbon dioxide and has a residence time of around 120 years. Different management practices such as conserving water through drip irrigation, monitoring soil nutrients to avoid overfertilization, and using cover crops in place of fertilizer application may help in reducing nitrous oxide emissions.
Reducing emissions
Agriculture is often not included in government emissions reduction plans. For example, the agricultural sector is exempt from the EU emissions trading scheme which covers around 40% of the EU greenhouse gas emissions.
See also
Agroecology
Effects of climate change on agriculture
Effects of climate change on livestock
Environmental issues with agriculture
References
External links
Climate change on the Food and Agriculture Organization of the United Nations website.
Report on the relationship between climate change, agriculture and food security by the International Food Policy Research Institute
Climate Change, Rice and Asian Agriculture: 12 Things to Know Asian Development Bank
Greenhouse gas emissions | Greenhouse gas emissions from agriculture | [
"Chemistry"
] | 2,347 | [
"Greenhouse gases",
"Greenhouse gas emissions"
] |
61,504,024 | https://en.wikipedia.org/wiki/C20H28FN3O3 | {{DISPLAYTITLE:C20H28FN3O3}}
The molecular formula C20H28FN3O3 (molar mass: 377.453 g/mol, exact mass: 377.2115 u) may refer to:
5F-ADB
5F-EMB-PINACA
Molecular formulas | C20H28FN3O3 | [
"Physics",
"Chemistry"
] | 75 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,504,407 | https://en.wikipedia.org/wiki/Crepuscular%20rays | Crepuscular rays, sometimes colloquially referred to as god rays, are sunbeams that originate when the Sun appears to be just above or below a layer of clouds, during the twilight period. Crepuscular rays are noticeable when the contrast between light and dark is most obvious. Crepuscular comes from the Latin word , meaning "twilight". Crepuscular rays usually appear orange because the path through the atmosphere at dawn and dusk passes through up to 40 times as much air as rays from a high Sun at noon. Particles in the air scatter short-wavelength light (blue and green) through Rayleigh scattering much more strongly than longer-wavelength yellow and red light.
Loosely, the term crepuscular rays is sometimes extended to the general phenomenon of rays of sunlight that appear to converge at a point in the sky, irrespective of time of day.
A rare related phenomena are anticrepuscular rays which can appear at the same time (and coloration) as crepuscular rays but in the opposite direction of the setting sun (east rather than west).
Gallery
See also
References
External links
Atmospheric optical phenomena
Sun | Crepuscular rays | [
"Physics"
] | 235 | [
"Optical phenomena",
"Physical phenomena",
"Atmospheric optical phenomena",
"Earth phenomena"
] |
61,505,702 | https://en.wikipedia.org/wiki/C22H26FN3O | {{DISPLAYTITLE:C22H26FN3O}}
The molecular formula C22H26FN3O (molar mass: 367.460 g/mol, exact mass: 367.2060 u) may refer to:
5F-CUMYL-P7AICA
5F-CUMYL-PINACA (SGT-25)
Molecular formulas | C22H26FN3O | [
"Physics",
"Chemistry"
] | 82 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,505,799 | https://en.wikipedia.org/wiki/NGC%201241 | NGC 1241 is a spiral galaxy located in the constellation Eridanus. It is located at a distance of circa 150 million light years from Earth, which, given its apparent dimensions, means that NGC 1241 is about 140,000 light years across. It was discovered by William Herschel on January 10, 1785. It is classified as a Seyfert galaxy.
NGC 1241 interacts with its smaller companion NGC 1242, forming a pair collectively known in the Atlas of Peculiar Galaxies as Arp 304.
Characteristics
NGC 1241 is a barred spiral galaxy seen at an inclination. It has two well defined dusty spiral arms, and thus is characterised as a grand design spiral galaxy. The bulge is boxy, characteristic of a barred galaxy, with the arms emerging from each end of the bar, with the north one appearing more tightly wound than the southern. The main arms branch into smaller ones.
A circumnuclear ring with active star formation has been detected in the central region of the galaxy. It appears clumpy and inclined and measures 5.6 × 3.4 arcseconds in diameter, lying just inside the inner Lindblad resonance. A faint spiral pattern with leading arms has been found to emanate from it in Paα emission, while in Ks and J band, the pattern appears trailing. NGC 1241 is one of the few galaxies with known trailing features in the nuclear regions, with the other being NGC 6902. Inside the circumnuclear ring was detected a bar like feature 1.6 arcseconds long that is almost perpendicular to the main bar of the galaxy.
The nucleus of NGC 1241 has been found to be active and it has been categorised as a type II Seyfert galaxy. The most accepted theory for the energy source of active galactic nuclei is the presence of an accretion disk around a supermassive black hole. The mass of the black hole in the centre of NGC 1241 is estimated to be 107.46 (29 million) .
The star formation rate of NGC 1241 is estimated to be 3.07 per year based on the H-alpha flux.
Nearby galaxies
NGC 1241 forms a pair with NGC 1242, which lies at an angular separation of 1.6 arcminutes. NGC 1243 lies 3.1 arcminutes away, but it has been identified as a double star in our galaxy. According to Garcia et al. the pair of galaxies is part of a galaxy group known as LGG 84, which also includes the galaxies NGC 1247, MCG -02-09-006, and Markarian 1071. A more recent study placed NGC 1241 in the same group as the galaxies NGC 1185, NGC 1204, NGC 1214, NGC 1215, NGC 1238, and NGC 1247.
Gallery
See also
NGC 7469 - another interacting Seyfert galaxy with a circumnuclear star formation ring
References
External links
NGC 1241 on SIMBAD
Barred spiral galaxies
Seyfert galaxies
Eridanus (constellation)
1241
11887
Astronomical objects discovered in 1785
Discoveries by William Herschel | NGC 1241 | [
"Astronomy"
] | 647 | [
"Eridanus (constellation)",
"Constellations"
] |
61,505,815 | https://en.wikipedia.org/wiki/C845H1343N223O243S9 | {{DISPLAYTITLE:C845H1343N223O243S9}}
The molecular formula C845H1343N223O243S9 (molar mass: 18802.638 g/mol) may refer to:
Filgrastim
Pegfilgrastim | C845H1343N223O243S9 | [
"Chemistry"
] | 71 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,505,880 | https://en.wikipedia.org/wiki/C17H18F3N3O3 | {{DISPLAYTITLE:C17H18F3N3O3}}
The molecular formula C17H18F3N3O3 (molar mass: 369.338 g/mol) may refer to:
Fleroxacin
RU-58841
Molecular formulas | C17H18F3N3O3 | [
"Physics",
"Chemistry"
] | 62 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,505,994 | https://en.wikipedia.org/wiki/C12H15FN2 | {{DISPLAYTITLE:C12H15FN2}}
The molecular formula C12H15FN2 (molar mass: 206.259 g/mol, exact mass: 206.1219 u) may refer to:
5-Fluoro-DMT (5-Fluoro-N,N-dimethyltryptamine)
6-Fluoro-DMT (6-Fluoro-N,N-dimethyltryptamine) | C12H15FN2 | [
"Chemistry"
] | 101 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
61,506,065 | https://en.wikipedia.org/wiki/C15H13FO2 | {{DISPLAYTITLE:C15H13FO2}}
The molecular formula C15H13FO2 (molar mass: 244.261 g/mol, exact mass: 244.089958 u) may refer to:
Flurbiprofen
Tarenflurbil (also called Flurizan)
Molecular formulas | C15H13FO2 | [
"Physics",
"Chemistry"
] | 72 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,506,164 | https://en.wikipedia.org/wiki/Click%20%28acoustics%29 | A click is a sonic artifact in sound and music production.
Analog recording artifact
On magnetic tape recordings, clicks can occur when switching from magnetic play to record in order to correct recording errors and when recording a track in sections. On phonograph records, clicks are perceived in various ways by the listener, ranging from tiny 'tick' noises which may occur in any recording medium through 'scratch' and 'crackle' noise commonly associated with analog disc recording methods. Analog clicks can occur due to dirt and dust on the grooves of the vinyl record or granularity in the material used for its manufacturing, or through damage to the disc from scratches on its surface.
Digital recording artifact
In digital recording, clicks (not to be confused with the click track) can occur due to multiple issues. When recording through an audio interface, insufficient computer performance or audio driver issues can cause clicks, pops and dropouts. They can result from improper clock sources and buffer size. Also, clicks can be caused by electric devices near the computer or by faulty audio or mains cables. In sample recording, digital clicks occur when the signal levels of two adjacent audio sections do not match. The abrupt change in gain can be perceived as a click. In electronic music, clicks are used as a musical element, particularly in glitch and noise music, for example in the Clicks & Cuts Series (2000–2010).
Speech noise
In speech recording, click noises (not to be confused with click consonants) result from tongue movements, swallowing, mouth and saliva noises. While in voice-over recordings, click noises are undesirable, they can be used as a sound effect of close-miking in ASMR and pop music, e.g. in Bad Guy (2019) by Billie Eilish.
Click removal
In audio restoration and audio editing, hardware and software de-clickers provide click removal or de-clicking features. A spectrogram can be used to visually detect clicks and crackles (corrective spectral editing).
See also
Crackling noise
Record restoration
Gaussian noise
Impulse noise (acoustics)
References
Further reading
External links
Click and pop removal techniques, Audacity tutorial
Noise (electronics)
Acoustics
Sound
Audio engineering
Sampling (music) | Click (acoustics) | [
"Physics",
"Engineering"
] | 454 | [
"Electrical engineering",
"Audio engineering",
"Classical mechanics",
"Acoustics"
] |
61,506,454 | https://en.wikipedia.org/wiki/C18H24N2S | {{DISPLAYTITLE:C18H24N2S}}
The molecular formula C18H24N2S (molar mass: 300.462 g/mol) may refer to:
Fourphit (4-isothiocyanato-1-[1-phenylcyclohexyl]piperidine)
Metaphit
Molecular formulas | C18H24N2S | [
"Physics",
"Chemistry"
] | 80 | [
"Molecules",
"Set index articles on molecular formulas",
"Isomerism",
"Molecular formulas",
"Matter"
] |
61,507,068 | https://en.wikipedia.org/wiki/KCNQ%20channels | KCNQ genes encode family members of the Kv7 potassium channel family. These include Kv7.1 (KCNQ1) - KvLQT1, Kv7.2 (KCNQ2), Kv7.3 (KCNQ3), Kv7.4 (KCNQ4), and Kv7.5 (KCNQ5). Four of these (KCNQ2-5) are expressed in the nervous system. They constitute a group of low-threshold voltage-gated K+ channels originally termed the ‘M-channel’ (see M-current). The M-channel name comes from the classically described mechanism wherein the activation of the muscarinic acetylcholine receptor deactivated this channel.
References
Potassium channels
Ion channels | KCNQ channels | [
"Chemistry"
] | 168 | [
"Neurochemistry",
"Ion channels",
"Molecular biology stubs",
"Molecular biology"
] |
78,169,854 | https://en.wikipedia.org/wiki/La%20Sociedad%20Interamericana%20de%20Astronom%C3%ADa%20en%20la%20Cultura | La Sociedad Interamericana de Astronomía en la Cultura (SIAC) is an organization dedicated to bringing together professionals in the field of cultural astronomy in the Americas.
History
SIAC was founded during the Symposium on Ethno- and Archaeoastronomy of the International Congress of Americanists (Simposio de etno y arqueoastronomía del Congreso Internacional de Americanistas) in Santiago, Chile, in 2003. During this meeting, present researchers discussed the necessity of having a professional organization in Latin America dedicated to cultural astronomy and founded the organization. In 2011, the organization applied for and received grant funding and began to organize more meetings.
Mission and activities
The main objective of SIAC is to promote the exchange and development of interdisciplinary research concerning astronomical knowledge and practices in their cultural context, as an important contribution to understanding the relationships between human societies and the environment in which they are located.
SIAC seeks to promote professional meetings (congresses, workshops, schools) and activities in cultural astronomy in the Americas. As of 2024, the Society has members from 13 countries, most of them in Latin America. Together with SEAC (Société Européenne pour l'Astronomie dans la Culture) and ISSAC (International Society for Archaeoastronomy and Astronomy in Culture), SIAC is one of the three international associations of cultural astronomy.
SIAC also keeps a catalog of publications that includes books, magazines, and newsletters.
External links
Official Website
Oral history interview with Alejandro López, 2015 August 11. Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/48449
References
Astronomy
Astronomical sub-disciplines
Archaeoastronomy | La Sociedad Interamericana de Astronomía en la Cultura | [
"Astronomy"
] | 374 | [
"nan",
"Archaeoastronomy",
"Astronomical sub-disciplines"
] |
78,170,816 | https://en.wikipedia.org/wiki/Neurosemiotics | Neurosemiotics is an area of science which studies the neural aspects of meaning making. It interconnects neurobiology, biosemiotics and cognitive semiotics. Neurolinguistics, neuropsychology and neurosemantics can be seen as parts of neurosemiotics.
Description
The pioneers of neurosemiotics include Jakob von Uexküll, Kurt Goldstein, Friedrich Rothschild, and others.
The first graduate courses on neurosemiotics were taught in some American and Canadian universities since 1970s. The term 'neurosemiotics' is also not much older.
Neurosemiotics demonstrates which are the necessary conditions and processes responsible for semiosis in the neural tissue. It also describes the differences in the complexity of meaning making in animals of different complexity of the nervous system and the brain.
See also
Semiotics
Zoosemiotics
References
Semiotics
Neuroscience | Neurosemiotics | [
"Biology"
] | 199 | [
"Neuroscience"
] |
78,171,013 | https://en.wikipedia.org/wiki/Pseudonajatoxin%20b | Pseudonajatoxin b, or Pt-b, is a highly potent and lethal long-chain α-neurotoxin found in the venom of the eastern brown snake (Pseudonaja textilis). While the pharmacodynamics of pseudonajatoxin b are currently undocumented, α-neurotoxins are known to cause neuromuscular paralysis by blocking cholinergic neurotransmission.
Source
Pseudonajatoxin b is present in the venom of the highly lethal eastern brown snake, Pseudonaja textilis, which is the leading cause of snakebites in Australia. The concentration of pseudonajatoxin b in venom of South Australian specimens is up to a hundred times higher than in those from Queensland.
Chemistry
Structure and homology
Pseudonajatoxin b is composed of a single polypeptide chain of 71 amino acids and features five disulphide bridges. It exhibits 61-73% sequence homology with other long neurotoxins. Distinctive characteristics of pseudonajatoxin b include a high occurrence of proline residues, particularly at positions 49 and 54, where valines are usually present. Moreover, it contains an additional amino acid in the loop between Cys-46 and Cys-58.
Protein family
Pseudonajatoxin b is a type of three-finger toxin, which are characterized by a structure of three loops that emerge from a hydrophobic core. Specifically, it falls within the long-chain subfamily of the α-neurotoxin group.
Target and mechanism of action
Although the pharmacodynamics of pseudonajatoxin b have not been documented, α-neurotoxins generally exhibit some common traits.
Long-chain α-neurotoxins have been shown to bind with high affinity to both muscular and neuronal nicotinic acetylcholine receptors. These receptors serve as the primary mediator of muscle contraction in response to nerve impulses. Additionally, they are present in the central nervous system, where they play an important role in autonomic processes, including the regulation of heart rate and respiration.
By acting as competitive antagonists to acetylcholine, α-neurotoxins block acetylcholine from binding and subsequently prevent the activation of ion channels. This disruption in neurotransmission effectively leads to neuromuscular paralysis. Importantly, since the activation of nicotinic acetylcholine receptors requires the binding of two acetylcholine molecules, the blockage of just one binding site by an α-neurotoxin is sufficient to prevent channel opening. Furthermore, long-chain α-neurotoxins typically bind tightly and irreversibly to nicotinic receptors, resulting in permanent channel inactivation once they are bound.
Toxicity and treatment
Pseudonajatoxin b is a highly potent toxin, with a median lethal dose (LD50) of 15 pg/kg in mice. Although the specific lethal mechanisms of pseudonajatoxin b remain unknown, it is well established that both α-neurotoxins and the venom of P. textilis induce paralysis, leading to death through asphyxiation.
Currently, no treatment specific for pseudonajatoxin b has been documented. However, envenomation from Pseudonaja textilis can be treated with snake antivenom made from antibodies, specifically horse immuno-globulins. Despite this, studies have shown that brown snake antivenom has low efficacy against Pseudonaja textilis venom.
References
Snake toxins
Peptides
Neurotoxins | Pseudonajatoxin b | [
"Chemistry"
] | 751 | [
"Biomolecules by chemical classification",
"Molecular biology",
"Neurochemistry",
"Neurotoxins",
"Peptides"
] |
78,171,477 | https://en.wikipedia.org/wiki/Delequamine | Delequamine (; developmental code names RS-15385, RS-15385-197) is a potent and selective α2-adrenergic receptor antagonist which was under development for the treatment of erectile dysfunction and major depressive disorder but was never marketed.
It is structurally related to the naturally occurring α2-adrenergic receptor antagonist yohimbine but has greater selectivity in comparison. The drug has been found to affect sexual function and sleep in humans.
Delequamine reached phase 3 clinical trials prior to the discontinuation of its development. The drug was under development in the 1990s and its development was discontinued by 1999. It was first described in the scientific literature by 1990.
References
Abandoned drugs
Alpha-2 blockers
Aphrodisiacs
Experimental antidepressants
Naphthyridines
Sulfonamides
Methoxy compounds | Delequamine | [
"Chemistry"
] | 179 | [
"Drug safety",
"Abandoned drugs"
] |
78,171,702 | https://en.wikipedia.org/wiki/Tianeptine/naloxone | Tianeptine/naloxone (developmental code names TNX-601, TNX-601-CR, TNX-601-ER), or naloxone/tianeptine, is an extended-release combination of tianeptine, an atypical μ-opioid receptor agonist, and naloxone, an orally inactive μ-opioid receptor antagonist, which was under development for the treatment of major depressive disorder, post-traumatic stress disorder (PTSD), and neurocognitive dysfunction associated with corticosteroid use but was never marketed.
Whereas tianeptine is marketed widely throughout Europe, Asia, and Latin America but is not available in the United States or the United Kingdom, tianeptine/naloxone was under development for registration in the United States and other countries. In addition, whereas tianeptine has a short duration of action and requires administration three times per day, tianeptine/naloxone was developed as an extended-release formulation with enhanced pharmacokinetics suitable for once-daily administration. The combination formulation employs tianeptine as the oxalate salt, which is said to have improved physicochemical properties for use in the extended-release formulation compared to the amorphous tianeptine sodium that is used in immediate-release tianeptine-only formulations. Naloxone is used in misuse-resistant oral drug formulations as it is inactive if taken orally but becomes active if oral tablets are crushed and administered parenterally, such as by injection.
Tianeptine/naloxone reached phase 2 clinical trials for major depressive disorder and phase 1 clinical trials for post-traumatic stress disorders and cognition dysfunction related to corticosteroid use prior to the discontinuation of its development. Its development was discontinued for all indications in October 2023 due to lack of effectiveness for major depressive disorder in a phase 2 clinical trial.
References
Abandoned drugs
Combination drugs
Experimental antidepressants
Experimental anxiolytics
Mu-opioid receptor agonists
Mu-opioid receptor antagonists | Tianeptine/naloxone | [
"Chemistry"
] | 445 | [
"Drug safety",
"Abandoned drugs"
] |
78,171,899 | https://en.wikipedia.org/wiki/PRAX-114 | PRAX-114 is a neurosteroid and GABAA receptor positive allosteric modulator which is under development for the treatment of major depressive disorder, essential tremor, depressive disorders, and epilepsy. It was also under development for the treatment of post-traumatic stress disorder (PTSD), but development for this indication was discontinued. The drug is taken by mouth.
PRAX-114 is described as an extrasynaptic-preferring GABAA receptor positive allosteric modulator with a wider separation between antidepressant-like activity and sedative effects in preclinical research than related drugs like zuranolone. It has 10.5-fold preference for potentation of extrasynaptic GABAA receptors over synaptic GABAA receptors in vitro. Hence, the drug is theorized to have improved tolerability. PRAX-114 shows antidepressant-like, anxiolytic-like, and, at higher doses, sedative effects in animals.
As of March 2023, PRAX-114 is in phase 2/3 clinical trials for major depressive disorder and phase 2 clinical trials for essential tremor. No recent development has been reported for treatment of depressive disorders and epilepsy. In a June 2023 literature review, it was reported that PRAX-114 had failed to show effectiveness in the treatment of major depressive disorder in a phase 2/3 trial and that there were no further plans to develop PRAX-114 for treatment of psychiatric disorders. The drug is or was under development by Praxis Pharmaceuticals. Aside from being a small molecule and neurosteroid, the chemical structure of PRAX-114 does not seem to have been disclosed.
References
Abandoned drugs
Drugs with undisclosed chemical structures
Experimental antidepressants
Experimental drugs
GABAA receptor positive allosteric modulators
Neurosteroids | PRAX-114 | [
"Chemistry"
] | 387 | [
"Drug safety",
"Abandoned drugs"
] |
78,172,058 | https://en.wikipedia.org/wiki/Pegipanermin | Pegipanermin (; developmental code names and proposed brand names DN-TNF, INB-03, LIVNate, Quellor XENP345, XPro1595) is a tumor necrosis factor α (TNFα) inhibitor which is under development for the treatment of Alzheimer's disease, mild cognitive impairment, major depressive disorder, and other indications. It is described as having potential anti-inflammatory effects. It is administered by subcutaneous injection.
The drug is a protein and PEGylated variant of TNFα that does not bind to the tumor necrosis factor receptors (TNF receptors) but instead binds to and forms heterotrimers with TNFα and prevents TNFα from activating the TNF receptors. However, pegipanermin is said to be selective for blocking TNFα activation of the tumor necrosis factor receptor 1 (TNFR1) but not of the tumor necrosis factor receptor 2 (TNFR2). Whereas the non-selective TNFα inhibitor etanercept suppressed hippocampal neurogenesis, learning, and memory in animals, pegipanermin did not do so, yet still inhibited neuroinflammation. Pegipanermin crosses the blood–brain barrier into the central nervous system.
As of October 2024, pegipanermin is in phase 2 clinical trials for Alzheimer's disease, mild cognitive impairment, and major depressive disorder. It is in the preclinical stage of development for HER2-positive breast cancer. No recent development has been reported for other neurodegenerative disorders, non-alcoholic steatohepatitis, or solid tumors. Development was discontinued for Parkinson's disease and COVID-19 respiratory infections.
See also
Infliximab
References
Anti-inflammatory agents
Experimental antidepressants
Experimental drugs
Experimental drugs for Alzheimer's disease
TNF inhibitors
Peptides | Pegipanermin | [
"Chemistry"
] | 397 | [
"Biomolecules by chemical classification",
"Peptides",
"Molecular biology"
] |
78,172,250 | https://en.wikipedia.org/wiki/NS-136 | NS-136 is a selective muscarinic acetylcholine M4 receptor positive allosteric modulator which is under development for the treatment of schizophrenia and Alzheimer's disease. It has been found to possess pro-cognitive effects in rodents. The drug is under development by NeuShen Therapeutics. As of May 2024, it is in phase 1 clinical trials for schizophrenia and is in the preclinical stage of development for Alzheimer's disease. The drug is a small molecule, but its chemical structure does not seem to have been disclosed.
See also
Emraclidine
NBI-1117568
Xanomeline
References
Drugs with undisclosed chemical structures
Experimental drugs for Alzheimer's disease
Experimental drugs developed for schizophrenia
M4 receptor positive allosteric modulators | NS-136 | [
"Chemistry"
] | 162 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
78,172,695 | https://en.wikipedia.org/wiki/AZD-2327 | AZD-2327 is a δ-opioid receptor agonist which was under development for the treatment of depressive disorders and anxiety disorders but was never marketed. It is taken by mouth.
Pharmacology
The drug showed antidepressant- and anxiolytic-like effects as well as locomotor-stimulating effects in animal models. It had reduced induction of seizures and locomotor hyperactivity compared to other δ-opioid receptor agonists. The doses required for stimulant-like activity were 3- to 10-fold greater than the doses that produced antidepressant- and anxiolytic-like effects. The drug appears to have a very low misuse potential based on animal studies. In addition to its δ-opioid receptor agonist activity, AZD-2327 has been reported to act as a cytochrome P450 CYP3A4 inhibitor.
It has been found to inhibit the release of norepinephrine caused by anxiety and was able to do so as much as the benzodiazepine diazepam. However, AZD-2327 could be advantageous to benzodiazepines because these drugs often cause rapid tolerance and dependence. In contrast to benzodiazepines, AZD-2327 may have less or no potential for tolerance in terms of its anxiolytic-like effects.
History
AZD-2327 was first described by 2004 and was first described in the scientific literature in 2009. The development of AZD-2327 was discontinued in 2010. It reached phase 2 clinical trials for both depressive disorders and anxiety disorders prior to its discontinuation. No reason was given for the discontinuation of its development. However, the drug was found to be ineffective for major depressive disorder in a phase 2 clinical trial. AZD-2327 was developed by AstraZeneca.
See also
AZD-7268
BW373U86
DPI-287
DPI-3290
References
4-Fluorophenyl compounds
Abandoned drugs
Amines
Anxiolytics
Benzamides
CYP3A4 inhibitors
Delta-opioid receptor agonists
Drugs developed by AstraZeneca
Experimental antidepressants
Experimental psychiatric drugs
Piperazines | AZD-2327 | [
"Chemistry"
] | 475 | [
"Drug safety",
"Functional groups",
"Amines",
"Bases (chemistry)",
"Abandoned drugs"
] |
78,173,183 | https://en.wikipedia.org/wiki/AZD-7268 | AZD-7268 is a δ-opioid receptor agonist which was under development for the treatment of major depressive disorder but was never marketed. It is taken by mouth.
The affinity (Ki) of AZD-7268 for the δ-opioid receptor was reported to be 2.7nM and its selectivity for this receptor over the μ-opioid receptor was reported to be 2,000-fold. No animal studies of AZD-7268 appear to have been published. In addition to putative antidepressant effects, AZD-7268 might have anxiolytic effects. Structurally, AZD-7268 was derived from SNC-80.
Dose-limiting side effects of AZD-7268 in clinical trials included syncope (fainting), hypotension (low blood pressure), and dizziness.
AZD-7268 was first described by 2007. Its development was discontinued in 2010. It reached phase 2 clinical trials prior to the discontinuation of its development. No reason was given for the discontinuation of its development. However, the drug was found to be ineffective for major depressive disorder in a phase 2 clinical trial of 231participants comparing it with placebo and escitalopram. The drug was under development by AstraZeneca.
See also
AZD-2327
References
Abandoned drugs
Benzamides
Delta-opioid receptor agonists
Drugs developed by AstraZeneca
Experimental antidepressants
Piperidines
Quinolines
Thiazoles
Ethanolamines | AZD-7268 | [
"Chemistry"
] | 336 | [
"Drug safety",
"Abandoned drugs"
] |
78,173,272 | https://en.wikipedia.org/wiki/Lu%2029-252 | Lu 29-252 is a selective sigma σ2 receptor ligand which was under development for the treatment of anxiety disorders but was never marketed. It reached the preclinical stage of development prior to the discontinuation of its development. The drug was under development by Lundbeck.
References
Abandoned drugs
Benzofurans
Experimental psychiatric drugs
Piperidines
Sigma receptor ligands
Spiro compounds | Lu 29-252 | [
"Chemistry"
] | 79 | [
"Pharmacology",
"Drug safety",
"Medicinal chemistry stubs",
"Organic compounds",
"Pharmacology stubs",
"Abandoned drugs",
"Spiro compounds"
] |
78,173,367 | https://en.wikipedia.org/wiki/OPC-64005 | OPC-64005 is a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI), or "triple reuptake inhibitor" (TRI), which is under development for the treatment of major depressive disorder. It was also under development for the treatment of attention deficit hyperactivity disorder (ADHD), but development for this indication was discontinued. It is taken by mouth.
As of December 2022, OPC-64005 is in phase 2 clinical trials for major depressive disorder. It reached phase 2 clinical trials for ADHD prior to the discontinuation of its development for this use. It completed a phase 2 clinical trial for ADHD comparing it with placebo and atomoxetine, but the results of this trial were not disclosed. The drug is under development by Otsuka Pharmaceutical. It is a small molecule, but its chemical structure does not appear to have been disclosed.
References
Drugs with undisclosed chemical structures
Experimental antidepressants
Serotonin–norepinephrine–dopamine reuptake inhibitors | OPC-64005 | [
"Chemistry"
] | 226 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
78,173,453 | https://en.wikipedia.org/wiki/ENX-104 | ENX-104, also known as deuterated nemonapride enantiomer, is a selective dopamine D2 and D3 receptor antagonist which is under development for the treatment of major depressive disorder. It is specifically under development for the treatment of major depressive disorder characterized by anhedonia. The drug is being developed for use at low doses to preferentially block presynaptic dopamine D2 and D3 autoreceptors and hence to enhance rather than inhibit dopaminergic neurotransmission. It is taken by mouth.
Pharmacology
Pharmacodynamics
ENX-104 is intended for use at low doses to produce preferential presynaptic dopamine D2 and D3 autoreceptor antagonism and consequent enhancement of dopaminergic neurotransmission. The target occupancy of the dopamine D2 and D3 receptors is approximately 40 to 70%. For comparison, dopamine D2 receptor occupancy of 65 to 80% is associated with antipsychotic-like effects and hence with substantial postsynaptic dopamine D2 receptor antagonism in animals. ENX-104 has been found to increase dopamine and serotonin levels in the nucleus accumbens and prefrontal cortex. It was also found to augment amphetamine-induced dopamine release. In accordance with these findings, the drug was found to produce anti-anhedonia-like effects, specifically increased reward responsiveness, in animals. Low doses of amisulpride likewise showed anti-anhedonia-like effects.
ENX-104 is not expected to induce motor side effects like extrapyramidal symptoms (EPS) or catalepsy at the low doses employed, as these effects require higher occupancy of the D2 receptor (e.g., ~80%).
ENX-104 is highly potent as a dopamine receptor antagonist. Its affinities are 0.01nM for the dopamine D2L receptor, 0.1nM for the dopamine D2S receptor, 0.2nM for the dopamine D3 receptor (2- to 20-fold lower than for the D2 receptor), and 1.6nM for the dopamine D4 receptor (8- to 160-fold lower than for the D2 receptor). The drug is also a weak partial agonist or antagonist of the serotonin 5-HT2A receptor, with an of 14nM (70- to 1,400-fold lower than its affinity for the D2 receptor) and an Emax of approximately 40%. Conversely, ENX-104 showed little or no functional activity at the serotonin 5-HT1A or 5-HT7 receptor.
Chemistry
ENX-104 is a benzamide derivative. It is a partially-deuterated analog of the drug nemonapride, which is used to treat schizophrenia.
Clinical trials
As of September 2024, ENX-104 is in phase 1 clinical trials for major depressive disorder. It is under development by Engrail Therapeutics.
See also
For the enantiomer, see ENX-105
References
Amines
Benzamides
Benzyl compounds
Chlorobenzene derivatives
D2 antagonists
D3 antagonists
Deuterated compounds
Experimental antidepressants
Pyrrolidines
Methoxy compounds | ENX-104 | [
"Chemistry"
] | 729 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
78,173,624 | https://en.wikipedia.org/wiki/Amanita%20constricta | Amanita constricta, commonly known as the constricted grisette or great grey-sack ringless amanita is a species of mushroom-forming fungus in the family Amanitaceae. It is edible, but it is not recommended for consumption due to confusion with poisonous species.
Description
Amanita constricta has a brown cap that is about wide. The stipe is about tall and about wide. The mushroom has a volva that tightly attaches to the stipe.
Habitat and ecology
Amanita constricta is mycorrhizal, and grows under oak and Douglas fir. It was originally described from California, but its range may extend up into Canada.
References
constricta
Fungi of North America
Fungi described in 1982
Taxa named by Harry Delbert Thiers
Fungus species | Amanita constricta | [
"Biology"
] | 170 | [
"Fungi",
"Fungus species"
] |
78,173,752 | https://en.wikipedia.org/wiki/International%20Women%20in%20Biomechanics | International Women in Biomechanics or the IWB is a not-for-profit organisation aimed at supporting gender equity in biomechanics and it aims to be a supportive and uplifting community for women and underrepresented genders in the field.
They have a membership of over 700 biomechanists from over 300 universities and organisations from 33 countries. The community contains ranges of career stages and professions and interacts through forums, meetings and social media.
About
The IWB was founded in July 2020 to support women in the biomechanics field and it creation was exacerbated by the COVID-19 Pandemic which increased professional isolation. It was formed by two postdoctoral fellows, Anahid (Ana) Ebrahimi, who is based in the US, and Jayishni Maharaj, who is based in Australia. Ebrahimi and Maharaj were interviewed on the Biomechanics On Our Minds (BOOM) podcast about establishing IWB.
In 2021 they conducted a survey to identify the needs, concerns and issues faced by their community and found that the primary needs for women in biomechanics were; supportive working environments, career planning support and assistance in addressing workplace gender bias. In response to this the IWB identified three key areas to support its mission:
Member support
Community outreach
Empowering allyship
The IWB has been an affiliate society of the International Society of Biomechanics since August 2023 and recipient of the American Society of Biomechanics 2022 Grants for Diversity, Equity, and Inclusion (GRADE) award.
The IWB are a sponsor of The Biomechanics Initiative grant program to support outreach for women in biomechanics
References
Biomechanics
2020 establishments
International learned societies | International Women in Biomechanics | [
"Physics"
] | 362 | [
"Biomechanics",
"Mechanics"
] |
78,173,887 | https://en.wikipedia.org/wiki/Butralin | Butralin is a preemergent herbicide used to control suckers on tobacco in the United States, Australia, Mozambique and, for food crops also, China. It is a dinitroaniline, first registered in the US in 1976. It was used in the EU until a ban in 2009 due to its ecotoxicity.
Mode of action and effects
Butralin works by the HRAC mode of action Group D / K1 / 3, (Australian, Global, Numeric respectively), which involves inhibition of microtubule formation, by binding to tubulin, halting growth, and causing depolymerization.
In ryegrass meristems, butralin-treated roots show reduced elongation, but greater diameter. The cells' rate of mitosis lowers 36% after one hour, and they develop multiple nuclei. Butralin's effect is more similar to carbamate herbicides such as chlorpropham rather than other dinitroanilines.
Usage
Butralin is sold in Mozambique as "Tobralin 36% EC", made in South Africa. Users are instructed to pour 10 mL on each tobacco plant by hand, and not to unclog nozzles with their mouths.
In China, over 100 tons per year are used, as of 2022, on garlic, soybean, tomato, rice, peanut, pepper, cotton, eggplant, and watermelon. The maximum residue limit is 0.02 to 0.1 mg/kg. The growing Chinese market sells it in 36% or 48% emulsifiable concentrates, and in development as of 2012, a 41% wettable powder. The powder claims to be environmentally friendly, as it lacks the volatile organic molecules such as toluene and xylene used as solvent in EC formulations. The powder is recommended to be applied at 2100 g/Ha (active ingredient).
Health
Butralin is of low acute toxicity. There is no association with lung cancer.
It is very toxic to Daphnia.
In soil
Butralin is likely to be moderately persistent to persistent and relatively immobile in terrestrial environments. Butralin is stable to abiotic hydrolysis and photodegradation on soil. Its characteristics are unlike those of chemicals that leach to groundwater. Butralin's major soil metabolite is 4-tert-butyl-2,6-dinitroaniline. Other major metabolites see the loss of more or all of the carbons and hydrogen over the nitrogen, or loss of oxygen from the nitro groups. The principle residue in crops, however, is the parent butralin.
References
Links
Preemergent herbicides
Nitrotoluene derivatives
Anilines
Herbicides
Products introduced in 1976
Sec-Butyl compounds
Tert-butyl compounds | Butralin | [
"Biology"
] | 587 | [
"Herbicides",
"Biocides"
] |
78,174,039 | https://en.wikipedia.org/wiki/Bromine%20perchlorate | Bromine perchlorate is an inorganic chemical compound with the formula BrOClO3. It is a shock and light-sensitive red liquid which decomposes above -20 °C.
Preparation and reactions
Bromine perchlorate can be produced from the reaction of cesium perchlorate and bromine fluorosulfate at -20 °C:
CsClO4 + BrSO3F → BrOClO3 + CsSO3F
Alternatively, it can also be produced by the reaction of chlorine perchlorate and bromine at -45 °C. Bromine perchlorate reacts with hydrogen bromide to regenerate bromine:
BrOClO3 + HBr → Br2 + HClO4
This compound also reacts with cesium perchlorate, to produce Cs[Br(ClO4)2], and various fluorocarbon halides, to produce fluoroalkyl perchlorates.
References
Bromine(I) compounds
Perchlorates | Bromine perchlorate | [
"Chemistry"
] | 202 | [
"Perchlorates",
"Salts"
] |
78,174,380 | https://en.wikipedia.org/wiki/Electrojet%20Zeeman%20Imaging%20Explorer | Electrojet Zeeman Imaging Explorer (EZIE) is a planned NASA heliophysics mission, that will study the Sun and space weather near Earth. It will consist of three CubeSats that will study the auroral electrojets, "by exploring a phenomenon called Zeeman splitting, which is the splitting of a molecule’s light spectrum when placed near a magnetic field". EZIE is expected to be launched in 2025.
Further reading
References
External links
Official website
2025 in spaceflight
NASA space probes
Solar space observatories | Electrojet Zeeman Imaging Explorer | [
"Astronomy"
] | 112 | [
"Space telescopes",
"Solar space observatories",
"Astronomy stubs",
"Spacecraft stubs"
] |
78,174,423 | https://en.wikipedia.org/wiki/Venus%20Volcano%20Imaging%20and%20Climate%20Explorer | Venus Volcano Imaging and Climate Explorer (VOICE) was a proposed orbiter mission to Venus by China National Space Administration. According to the proposal, VOICE will study "Venusian volcanic and thermal evolution history, water and plate tectonics, internal structure and dynamics, climate evolution, possible habitable environment and life information in the clouds". The mission is part of the Tianwen program, and is expected to be launched in 2026, and arrive at Venus at 2027.
VOICE will have three instruments: Polarimetric Synthetic Aperture Radar (PolSAR), Microwave Radiometric Sounder (MWRS) and Ultraviolet-Visible-Near Infrared Multi-Spectral Imager (UVN-MSI).
The mission competed with 12 other missions under the Strategic Priority Program on Space Science III (SPP-III) for 2025-2030. According to the National Space Science Medium- and Long-Term Development Plan (2024-2050), the mission was not selected for development. It was replaced by a Venus atmosphere sample return mission, but no details or timelines were announced.
References
Chinese space probes
Missions to Venus
Proposed space probes | Venus Volcano Imaging and Climate Explorer | [
"Astronomy"
] | 233 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
78,175,200 | https://en.wikipedia.org/wiki/Premonoidal%20category | In category theory, a premonoidal category is a generalisation of a monoidal category where the monoidal product need not be a bifunctor, but only to be functorial in its two arguments separately. This is in analogy with the concept of separate continuity in topology.
Premonoidal categories naturally arise in theoretical computer science as the Kleisli categories of strong monads. They also have a graphical language given by string diagrams with an extra wire going through each box so that they cannot be reordered.
Funny tensor product
The category of small categories is a closed monoidal category in exactly two ways: with the usual categorical product and with the funny tensor product. Given two categories and , let be the category with functors as objects and unnatural transformations as arrows, i.e. families of morphisms which do not necessarily satisfy the condition for a natural transformation.
The funny tensor product is the left adjoint of unnatural transformations, i.e. there is a natural isomorphism for currying. It can be defined explicitly as the pushout of the span where are the discrete categories of objects of and the two functors are inclusions. In the case of groups seen as one-object categories, this is called the free product.
Sesquicategories
The same way we can define a monoidal category as a one-object 2-category, i.e. an enriched category over with the Cartesian product as monoidal structure, we can define a premonoidal category as a one-object sesquicategory, i.e. a category enriched over with the funny tensor product as monoidal structure. This is called a sesquicategory (literally, "one-and-a-half category") because it is like a 2-category without the interchange law .
References
External links
Premonoidal category, funny tensor product and sesquicategory at the nLab
Categories in category theory | Premonoidal category | [
"Mathematics"
] | 402 | [
"Mathematical structures",
"Category theory",
"Categories in category theory"
] |
78,175,509 | https://en.wikipedia.org/wiki/Ethalfluralin | Ethalfluralin is a herbicide. It is a preëmergent dinitroaniline developed from trifluralin, used to control annual grasses and broad-leaved weeds. It was synthesised in 1971, first sold in Turkey in 1975, the United States in 1983. It is used on soybeans, peanuts, potatoes, and as of 2023, is the first conventional herbicide the EPA permits on hemp, as ethalfluralin leaves no residue in the plant. Ethalfluralin is not used domestically.
Ethalfluralin did not leach in soil, and the EPA expects it not to contaminate ground water, though it notes the chemically very similar trifluralin has been found in groundwater. Ethalfluralin is very toxic to fish.
Ethalfluralin works by inhibition of microtubule formation, preventing cell division, and is a Group D / Group K1 / Group 3 herbicide (Australian, Global and numeric HRAC respectively). It is applied at approximately 1 kg/Ha.
In 2024, ethalfluralin was registered in India.
Health effects
Ethalfluralin is practically non-toxic to birds and mammals, though it causes moderate eye and skin irritation, and skin sensitisation. Subchronic rat and mice studies saw effects to the liver and kidneys, reduced weight gain, and affected enzyme activity. The EPA regards ethalfluralin as a possible carcinogen, due to tumours in chronically exposed rats. Ethalfluralin did not affect the reproductive system or cause strong mutagenisis.
Dietary effect is unlikely as ethalfluralin does not leave residues in plants and doesn't translocate.
Tradenames
Ethalfluralin has been sold as Gilan, Sonalan, Curbit, Sonalen and Edge.
References
Links
Preemergent herbicides
Nitrotoluene derivatives
Anilines
Herbicides
Trifluoromethyl compounds | Ethalfluralin | [
"Biology"
] | 419 | [
"Herbicides",
"Biocides"
] |
78,175,533 | https://en.wikipedia.org/wiki/HIP%2065Ab | HIP 65Ab (TOI-129 b) is a hot Jupiter discovered in 2020 orbiting the K-type main-sequence star HIP 65A, located approximately distant in the southern constellation of Phoenix. It completes one orbit around its host star every , making it an ultra-short period planet. Its radius is likely smaller than another estimate of is likely an overestimate.
Due to the planet's vicinity to the star, tidal interactions are slowly causing its orbit to decay. As such, the planet is expected to spiral into HIP 65A and be destroyed by its Roche limit within somewhere between 80 million years and a few billion years.
Physical properties
HIP 65Ab is a massive super-Jupiter with a mass of about 3 . Its unusually large radius of roughly 2 is likely overestimated, caused by the grazing nature of its transit, that is to say the planet only partially transits the disc of the host star. This is also why the radius has such a large margin of error.
It orbits extremely close to its star at a distance of , or about twice the radius of the Sun. As a result, the planet receives 661 times the flux Earth does, placing its equilibrium temperature at , just above the melting point of copper. Based on the planet's mass and temperature, HIP 65Ab is unlikely to be larger than 1.5 . A 2024 study agrees with this, stating that the planet's true radius is close to the presented lower limit.
The characteristics of the massive planet and its 23.5-hour orbit make it a prime target for accurate atmospheric observations. Its atmosphere was analysed spectroscopically for the first time in 2024, revealing absorption lines of water and carbon monoxide. Both molecules, however, are less abundant than they would be if the planet had a Sun-like composition. The results are consistent with the planet having a sub-solar metallicity but an overabundance of carbon and oxygen. This implies the planet may have formed beyond the snow line and migrated inward after the protoplanetary disk dissipated, or alternatively that some of the oxygen has precipitated out of the atmosphere.
Host star
HIP 65A is a K-type main-sequence star with the spectral type K4V, which corresponds to its effective temperature of (). This, combined with a radius of 0.7242 , means that it radiates around 21% of the luminosity of the Sun from its photosphere. The star has a mass of 0.74 , a rotation period of 13.2 days, and an age of billion years. Despite its planet's low metallicity, the star itself is richer in heavy elements than the Sun with a metallicity of .
It is a planetary transit variable, dimming by about 8% each time the planet passes in front of the star. This large transit depth, along with the star's high X-ray luminosity of erg/cm−2 s−1 make HIP 65A one of the best candidates for transit observations using X-ray telescopes.
The star is part of a wide binary system with HIP 65B, an M-type red dwarf star which has a mass of 0.3 and an effective temperature of . The two stars are separated by 3.95 arcseconds in the sky as seen from Earth, which corresponds to a distance of 269 AU.
References
Phoenix (constellation)
Transiting exoplanets
Exoplanets discovered in 2020
Hot Jupiters
Giant planets | HIP 65Ab | [
"Astronomy"
] | 712 | [
"Phoenix (constellation)",
"Constellations"
] |
78,177,631 | https://en.wikipedia.org/wiki/History%20of%20gasoline | The history of gasoline started around the invention of internal combustion engines suitable for use in transportation applications. The so-called Otto engines were developed in Germany during the last quarter of the 19th century. The fuel for these early engines was a relatively volatile hydrocarbon obtained from coal gas. With a boiling point near (n-octane boils at ), it was well-suited for early carburetors (evaporators). The development of a "spray nozzle" carburetor enabled the use of less volatile fuels. Further improvements in engine efficiency were attempted at higher compression ratios, but early attempts were blocked by the premature explosion of fuel, known as knocking.
In 1891, the Shukhov cracking process became the world's first commercial method to break down heavier hydrocarbons in crude oil to increase the percentage of lighter products compared to simple distillation.
Etymology
The American English word gasoline denotes fuel for automobiles, which common usage shortened to the terms gas, or rarely motor gas and mogas, thus differentiating it from avgas (aviation gasoline), which is fuel for airplanes. English dictionaries, including the Oxford English Dictionary, show that the term gasoline originates from gas plus the chemical suffixes -ole and -ine. However, a blog post at the defunct website Oxford Dictionaries alternatively proposes that the word may have originated from the surname of British businessman John Cassell, who supposedly first marketed the substance.
In place of the word gasoline, most Commonwealth countries (except Canada), use the term "petrol", and North Americans more often use "gas" in common parlance, hence the prevalence of the usage gas station in the United States.
Coined from Medieval Latin, the word petroleum (L. petra, rock + oleum, oil) initially denoted types of mineral oil derived from rocks and stones. In Britain, Petrol was a refined mineral oil product marketed as a solvent from the 1870s by the British wholesaler Carless Refining and Marketing Ltd. When Petrol found a later use as a motor fuel, Frederick Simms, an associate of Gottlieb Daimler, suggested to John Leonard, owner of Carless, that they trademark the word and uppercase spelling Petrol. The trademark application was refused because petrol had already become an established general term for motor fuel. Due to the firm's age, Carless retained the legal rights to the term and to the uppercase spelling of "Petrol" as the name of a petrochemical product.
British refiners originally used "motor spirit" as a generic name for the automotive fuel and "aviation spirit" for aviation gasoline. When Carless was denied a trademark on "petrol" in the 1930s, its competitors switched to the more popular name "petrol". However, "motor spirit" had already made its way into laws and regulations, so the term remains in use as a formal name for petrol. The term is used most widely in Nigeria, where the largest petroleum companies call their product "premium motor spirit". Although "petrol" has made inroads into Nigerian English, "premium motor spirit" remains the formal name that is used in scientific publications, government reports, and newspapers.
Some other languages use variants of gasoline. is used in Spanish and Portuguese, and is used in Japanese. In other languages, the name of the product is derived from the hydrocarbon compound benzene, or more precisely from the class of products called petroleum benzine, such as in German or in Italian; but in Argentina, Uruguay, and Paraguay, the colloquial name is derived from that of the chemical naphtha.
Some languages, like French and Italian, use the respective words for gasoline to instead indicate diesel fuel.
Brief technical timeline
Subsequent to the inventions of Daimler, Benz, Otto, and others the growth in the production and consumption of gasoline involved many innovations. One might summarize the timeline in the following way: the first 50 years were focused on the internal combustion engine and on refinery operations and, post 1970, emphasis has been placed on safety and automobile emissions.
1900-1910 invention of spray carbeurator allowed use of "straight run gasoline" with vehicles. Straight run gasoline is obtained simply by distillation of petroleum.
1910-1920 improvements in compression ratio gave automobiles more power
1920–1930 engine knocking, which limited advances in compression ratio, is addressed with tetraethyllead
1930–1950 Eugene Houdry and other introduced and steadily improved catalytic cracking technologies, allowing a greater proportion of petroleum to be used for fuels
1940–1990 improved catalysts are introduced based on zeolites, molybdenum, and platinum for cracking, desulfurization, and reforming. These technologies provided cleaner burning high octane fuels
1970–1990 tetraethyllead is replaced by octane enhancers, and catalytic converters are introduced.
Effects of world wars on gasoline
1903 to 1914
The evolution of gasoline followed the evolution of oil as the dominant source of energy in the industrializing world. Before World War I, Britain was the world's greatest industrial power and depended on its navy to protect the shipping of raw materials from its colonies. Germany was also industrializing and, like Britain, lacked many natural resources which had to be shipped to the home country. By the 1890s, Germany began to pursue a policy of global prominence and began building a navy to compete with Britain's. Coal was the fuel that powered their navies. Though both Britain and Germany had natural coal reserves, new developments in oil as a fuel for ships changed the situation. Coal-powered ships were a tactical weakness because the process of loading coal was slow and dirty and left the ship completely vulnerable to attack, and unreliable supplies of coal at international ports made long-distance voyages impractical. The advantages of petroleum oil soon found the navies of the world converting to oil, but Britain and Germany had very few domestic oil reserves. Britain eventually solved its naval oil dependence by securing oil from Royal Dutch Shell and the Anglo-Persian Oil Company and this determined from where and of what quality its gasoline would come.
During the early period of gasoline engine development, aircraft were forced to use motor vehicle gasoline since aviation gasoline did not yet exist. These early fuels were termed "straight-run" gasolines and were byproducts from the distillation of a single crude oil to produce kerosene, which was the principal product sought for burning in kerosene lamps. Gasoline production would not surpass kerosene production until 1916. The earliest straight-run gasolines were the result of distilling eastern crude oils and there was no mixing of distillates from different crudes. The composition of these early fuels was unknown, and the quality varied greatly. The engine effects produced by abnormal combustion (engine knocking and pre-ignition) due to inferior fuels had not yet been identified, and as a result, there was no rating of gasoline in terms of its resistance to abnormal combustion. The general specification by which early gasolines were measured was that of specific gravity via the Baumé scale and later the volatility (tendency to vaporize) specified in terms of boiling points, which became the primary focuses for gasoline producers. These early eastern crude oil gasolines had relatively high Baumé test results (65 to 80 degrees Baumé) and were called "Pennsylvania high-test" or simply "high-test" gasolines. These were often used in aircraft engines.
By 1910, increased automobile production and the resultant increase in gasoline consumption produced a greater demand for gasoline. Also, the growing electrification of lighting produced a drop in kerosene demand, creating a supply problem. It appeared that the burgeoning oil industry would be trapped into over-producing kerosene and under-producing gasoline since simple distillation could not alter the ratio of the two products from any given crude. The solution appeared in 1911 when the development of the Burton process allowed thermal cracking of crude oils, which increased the percent yield of gasoline from the heavier hydrocarbons. This was combined with the expansion of foreign markets for the export of surplus kerosene which domestic markets no longer needed. These new thermally "cracked" gasolines were believed to have no harmful effects and would be added to straight-run gasolines. There also was the practice of mixing heavy and light distillates to achieve the desired Baumé reading and collectively these were called "blended" gasolines.
Gradually, volatility gained favor over the Baumé test, though both continued to be used in combination to specify a gasoline. As late as June 1917, Standard Oil (the largest refiner of crude oil in the United States at the time) stated that the most important property of a gasoline was its volatility. It is estimated that the rating equivalent of these straight-run gasolines varied from 40 to 60 octane and that the "high-test", sometimes referred to as "fighting grade", probably averaged 50 to 65 octane.
World War I
Prior to the United States entry into World War I, the European Allies used fuels derived from crude oils from Borneo, Java, and Sumatra, which gave satisfactory performance in their military aircraft. When the U.S. entered the war in April 1917, the U.S. became the principal supplier of aviation gasoline to the Allies and a decrease in engine performance was noted. Soon it was realized that motor vehicle fuels were unsatisfactory for aviation, and after the loss of several combat aircraft, attention turned to the quality of the gasolines being used. Later flight tests conducted in 1937 showed that an octane reduction of 13 points (from 100 down to 87 octane) decreased engine performance by 20 percent and increased take-off distance by 45 percent. If abnormal combustion were to occur, the engine could lose enough power to make getting airborne impossible and a take-off roll became a threat to the pilot and aircraft.
On 2 August 1917, the U.S. Bureau of Mines arranged to study fuels for aircraft in cooperation with the Aviation Section of the U.S. Army Signal Corps and a general survey concluded that no reliable data existed for the proper fuels for aircraft. As a result, flight tests began at Langley, McCook and Wright fields to determine how gasolines performed under various conditions. These tests showed that in certain aircraft, motor vehicle gasolines performed as well as "high-test" but in other types resulted in hot-running engines. It was also found that gasolines from aromatic and naphthenic base crude oils from California, South Texas, and Venezuela resulted in smooth-running engines. These tests resulted in the first government specifications for motor gasolines (aviation gasolines used the same specifications as motor gasolines) in late 1917.
U.S., 1918–1929
Engine designers knew that, according to the Otto cycle, power and efficiency increased with compression ratio, but experience with early gasolines during World War I showed that higher compression ratios increased the risk of abnormal combustion, producing lower power, lower efficiency, hot-running engines, and potentially severe engine damage. To compensate for these poor fuels, early engines used low compression ratios, which required relatively large, heavy engines with limited power and efficiency. The Wright brothers' first gasoline engine used a compression ratio as low as 4.7-to-1, developed only from , and weighed . This was a major concern for aircraft designers and the needs of the aviation industry provoked the search for fuels that could be used in higher-compression engines.
Between 1917 and 1919, the amount of thermally cracked gasoline utilized almost doubled. Also, the use of natural gasoline increased greatly. During this period, many U.S. states established specifications for motor gasoline but none of these agreed and they were unsatisfactory from one standpoint or another. Larger oil refiners began to specify unsaturated material percentage (thermally cracked products caused gumming in both use and storage while unsaturated hydrocarbons are more reactive and tend to combine with impurities leading to gumming). In 1922, the U.S. government published the first specifications for aviation gasolines (two grades were designated as "fighting" and "domestic" and were governed by boiling points, color, sulfur content, and a gum formation test) along with one "motor" grade for automobiles. The gum test essentially eliminated thermally cracked gasoline from aviation usage and thus aviation gasolines reverted to fractionating straight-run naphthas or blending straight-run and highly treated thermally cracked naphthas. This situation persisted until 1929.
The automobile industry reacted to the increase in thermally cracked gasoline with alarm. Thermal cracking produced large amounts of both mono- and diolefins (unsaturated hydrocarbons), which increased the risk of gumming. Also, the volatility was decreasing to the point that fuel did not vaporize and was sticking to spark plugs and fouling them, creating hard starting and rough running in winter and sticking to cylinder walls, bypassing the pistons and rings, and going into the crankcase oil. One journal stated, "on a multi-cylinder engine in a high-priced car we are diluting the oil in the crankcase as much as 40 percent in a run, as the analysis of the oil in the oil-pan shows".
Being very unhappy with the consequent reduction in overall gasoline quality, automobile manufacturers suggested imposing a quality standard on the oil suppliers. The oil industry in turn accused the automakers of not doing enough to improve vehicle economy, and the dispute became known within the two industries as "the fuel problem". Animosity grew between the industries, each accusing the other of not doing anything to resolve matters, and their relationship deteriorated. The situation was only resolved when the American Petroleum Institute (API) initiated a conference to address the fuel problem and a cooperative fuel research (CFR) committee was established in 1920, to oversee joint investigative programs and solutions. Apart from representatives of the two industries, the Society of Automotive Engineers (SAE) also played an instrumental role, with the U.S. Bureau of Standards being chosen as an impartial research organization to carry out many of the studies. Initially, all the programs were related to volatility and fuel consumption, ease of starting, crankcase oil dilution, and acceleration.
Leaded gasoline controversy, 1924–1925
With the increased use of thermally cracked gasolines came an increased concern regarding its effects on abnormal combustion, and this led to research for antiknock additives. In the late 1910s, researchers such as A.H. Gibson, Harry Ricardo, Thomas Midgley Jr., and Thomas Boyd began to investigate abnormal combustion. Beginning in 1916, Charles F. Kettering of General Motors began investigating additives based on two paths, the "high percentage" solution (where large quantities of ethanol were added) and the "low percentage" solution (where only 0.53–1.1 g/L or 0.071–0.147 oz / U.S. gal were needed). The "low percentage" solution ultimately led to the discovery of tetraethyllead (TEL) in December 1921, a product of the research of Midgley and Boyd and the defining component of leaded gasoline. This innovation started a cycle of improvements in fuel efficiency that coincided with the large-scale development of oil refining to provide more products in the boiling range of gasoline. Ethanol could not be patented but TEL could, so Kettering secured a patent for TEL and began promoting it instead of other options.
The dangers of compounds containing lead were well-established by then and Kettering was directly warned by Robert Wilson of MIT, Reid Hunt of Harvard, Yandell Henderson of Yale, and Erik Krause of the University of Potsdam in Germany about its use. Krause had worked on tetraethyllead for many years and called it "a creeping and malicious poison" that had killed a member of his dissertation committee. On 27 October 1924, newspaper articles around the nation told of the workers at the Standard Oil refinery near Elizabeth, New Jersey who were producing TEL and were suffering from lead poisoning. By 30 October, the death toll had reached five. In November, the New Jersey Labor Commission closed the Bayway refinery and a grand jury investigation was started which had resulted in no charges by February 1925. Leaded gasoline sales were banned in New York City, Philadelphia, and New Jersey. General Motors, DuPont, and Standard Oil, who were partners in Ethyl Corporation, the company created to produce TEL, began to argue that there were no alternatives to leaded gasoline that would maintain fuel efficiency and still prevent engine knocking. After several industry-funded flawed studies reported that TEL-treated gasoline was not a public health issue, the controversy subsided.
U.S., 1930–1941
In the five years prior to 1929, a great amount of experimentation was conducted on various testing methods for determining fuel resistance to abnormal combustion. It appeared engine knocking was dependent on a wide variety of parameters including compression, ignition timing, cylinder temperature, air-cooled or water-cooled engines, chamber shapes, intake temperatures, lean or rich mixtures, and others. This led to a confusing variety of test engines that gave conflicting results, and no standard rating scale existed. By 1929, it was recognized by most aviation gasoline manufacturers and users that some kind of antiknock rating must be included in government specifications. In 1929, the octane rating scale was adopted, and in 1930, the first octane specification for aviation fuels was established. In the same year, the U.S. Army Air Force specified fuels rated at 87 octane for its aircraft as a result of studies it had conducted.
During this period, research showed that hydrocarbon structure was important to the antiknocking properties of fuel. Straight-chain paraffins in the boiling range of gasoline had low antiknock qualities while ring-shaped molecules such as aromatic hydrocarbons (for example benzene) had higher resistance to knocking. This development led to the search for processes that would produce more of these compounds from crude oils than achieved under straight distillation or thermal cracking. Research by the major refiners led to the development of processes involving isomerization of cheap and abundant butane to isobutane, and alkylation to join isobutane and butylenes to form isomers of octane such as "isooctane", which became an important component in aviation fuel blending. To further complicate the situation, as engine performance increased, the altitude that aircraft could reach also increased, which resulted in concerns about the fuel freezing. The average temperature decrease is per increase in altitude, and at , the temperature can approach . Additives like benzene, with a freezing point of , would freeze in the gasoline and plug fuel lines. Substituted aromatics such as toluene, xylene, and cumene, combined with limited benzene, solved the problem.
By 1935, there were seven grades of aviation fuels based on octane rating, two Army grades, four Navy grades, and three commercial grades including the introduction of 100-octane aviation gasoline. By 1937, the Army established 100-octane as the standard fuel for combat aircraft, and to add to the confusion, the government now recognized 14 distinct grades, in addition to 11 others in foreign countries. With some companies required to stock 14 grades of aviation fuel, none of which could be interchanged, the effect on the refiners was negative. The refining industry could not concentrate on large capacity conversion processes for so many grades and a solution had to be found. By 1941, principally through the efforts of the Cooperative Fuel Research Committee, the number of grades for aviation fuels was reduced to three: 73, 91, and 100 octane.
The development of 100-octane aviation gasoline on an economic scale was due in part to Jimmy Doolittle, who had become Aviation Manager of Shell Oil Company. He convinced Shell to invest in refining capacity to produce 100-octane on a scale that nobody needed since no aircraft existed that required a fuel that nobody made. Some fellow employees would call his effort "Doolittle's million-dollar blunder" but time would prove Doolittle correct. Before this, the Army had considered 100-octane tests using pure octane but at , the price prevented this from happening. In 1929, Stanavo Specification Board Inc. was organized by the Standard Oil companies of California, Indiana, and New Jersey to improve aviation fuels and oils and by 1935 had placed their first 100 octane fuel on the market, Stanavo Ethyl Gasoline 100. It was used by the Army, engine manufacturers and airlines for testing and for air racing and record flights. By 1936, tests at Wright Field using the new, cheaper alternatives to pure octane proved the value of 100 octane fuel, and both Shell and Standard Oil would win the contract to supply test quantities for the Army. By 1938, the price was down to , only more than 87 octane fuel. By the end of WWII, the price would be down to .
In 1937, Eugene Houdry developed the Houdry process of catalytic cracking, which produced a high-octane base stock of gasoline which was superior to the thermally cracked product since it did not contain the high concentration of olefins. In 1940, there were only 14 Houdry units in operation in the U.S.; by 1943, this had increased to 77, either of the Houdry process or of the Thermofor Catalytic or Fluid Catalyst type.
The search for fuels with octane ratings above 100 led to the extension of the scale by comparing power output. A fuel designated grade 130 would produce 130 percent as much power in an engine as it would running on pure iso-octane. During WWII, fuels above 100-octane were given two ratings, a rich and a lean mixture, and these would be called 'performance numbers' (PN). 100-octane aviation gasoline would be referred to as 130/100 grade.
World War II
Germany
Oil and its byproducts, especially high-octane aviation gasoline, would prove to be a driving concern for how Germany conducted the war. As a result of the lessons of World War I, Germany had stockpiled oil and gasoline for its blitzkrieg offensive and had annexed Austria, adding per day of oil production, but this was not sufficient to sustain the planned conquest of Europe. Because captured supplies and oil fields would be necessary to fuel the campaign, the German high command created a special squad of oilfield experts drawn from the ranks of domestic oil industries. They were sent in to put out oilfield fires and get production going again as soon as possible. But capturing oilfields remained an obstacle throughout the war. During the Invasion of Poland, German estimates of gasoline consumption turned out to be vastly too low. Heinz Guderian and his Panzer divisions consumed nearly of gasoline on the drive to Vienna. When they were engaged in combat across open country, gasoline consumption almost doubled. On the second day of battle, a unit of the XIX Corps was forced to halt when it ran out of gasoline. One of the major objectives of the Polish invasion was their oil fields but the Soviets invaded and captured 70 percent of the Polish production before the Germans could reach it. Through the German–Soviet Commercial Agreement (1940), Stalin agreed in vague terms to supply Germany with additional oil equal to that produced by now Soviet-occupied Polish oilfields at Drohobych and Boryslav in exchange for hard coal and steel tubing.
Even after the Nazis conquered the vast territories of Europe, this did not help the gasoline shortage. This area had never been self-sufficient in oil before the war. In 1938, the area that would become Nazi-occupied produced per day. In 1940, total production under German control amounted to only . By early 1941 and the depletion of German gasoline reserves, Adolf Hitler saw the invasion of Russia to seize the Polish oil fields and the Russian oil in the Caucasus as the solution to the German gasoline shortage. As early as July 1941, following the 22 June start of Operation Barbarossa, certain Luftwaffe squadrons were forced to curtail ground support missions due to shortages of aviation gasoline. On 9 October, the German quartermaster general estimated that army vehicles were short of gasoline requirements.
Virtually all of Germany's aviation gasoline came from synthetic oil plants that hydrogenated coals and coal tars. These processes had been developed during the 1930s as an effort to achieve fuel independence. There were two grades of aviation gasoline produced in volume in Germany, the B-4 or blue grade and the C-3 or green grade, which accounted for about two-thirds of all production. B-4 was equivalent to 89-octane and the C-3 was roughly equal to the U.S. 100-octane, though lean mixture was rated around 95-octane and was poorer than the U.S. version. Maximum output achieved in 1943 reached a day before the Allies decided to target the synthetic fuel plants. Through captured enemy aircraft and analysis of the gasoline found in them, both the Allies and the Axis powers were aware of the quality of the aviation gasoline being produced and this prompted an octane race to achieve the advantage in aircraft performance. Later in the war, the C-3 grade was improved to where it was equivalent to the U.S. 150 grade (rich mixture rating).
Japan
Japan, like Germany, had almost no domestic oil supply and by the late 1930s, produced only seven percent of its own oil while importing the rest80 percent from the U.S.. As Japanese aggression grew in China (USS Panay incident) and news reached the American public of Japanese bombing of civilian centers, especially the bombing of Chungking, public opinion began to support a U.S. embargo. A Gallup poll in June 1939 found that 72 percent of the American public supported an embargo on war materials to Japan. This increased tensions between the U.S. and Japan, and it led to the U.S. placing restrictions on exports. In July 1940, the U.S. issued a proclamation that banned the export of 87 octane or higher aviation gasoline to Japan. This ban did not hinder the Japanese as their aircraft could operate with fuels below 87 octane and if needed they could add TEL to increase the octane. As it turned out, Japan bought 550 percent more sub-87 octane aviation gasoline in the five months after the July 1940 ban on higher octane sales. The possibility of a complete ban of gasoline from America created friction in the Japanese government as to what action to take to secure more supplies from the Dutch East Indies and demanded greater oil exports from the exiled Dutch government after the Battle of the Netherlands. This action prompted the U.S. to move its Pacific fleet from Southern California to Pearl Harbor to help stiffen British resolve to stay in Indochina. With the Japanese invasion of French Indochina in September 1940, came great concerns about the possible Japanese invasion of the Dutch Indies to secure their oil. After the U.S. banned all exports of steel and iron scrap, the next day, Japan signed the Tripartite Pact and this led Washington to fear that a complete U.S. oil embargo would prompt the Japanese to invade the Dutch East Indies. On 16 June 1941 Harold Ickes, who was appointed Petroleum Coordinator for National Defense, stopped a shipment of oil from Philadelphia to Japan in light of the oil shortage on the East coast due to increased exports to Allies. He also telegrammed all oil suppliers on the East coast not to ship any oil to Japan without his permission. President Roosevelt countermanded Ickes's orders telling Ickes that the "I simply have not got enough Navy to go around and every little episode in the Pacific means fewer ships in the Atlantic". On 25 July 1941, the U.S. froze all Japanese financial assets and licenses would be required for each use of the frozen funds including oil purchases that could produce aviation gasoline. On 28 July 1941, Japan invaded southern Indochina.
The debate inside the Japanese government as to its oil and gasoline situation was leading to invasion of the Dutch East Indies but this would mean war with the U.S., whose Pacific fleet was a threat to their flank. This situation led to the decision to attack the U.S. fleet at Pearl Harbor before proceeding with the Dutch East Indies invasion. On 7 December 1941, Japan attacked Pearl Harbor, and the next day the Netherlands declared war on Japan, which initiated the Dutch East Indies campaign. But the Japanese missed a golden opportunity at Pearl Harbor. "All of the oil for the fleet was in surface tanks at the time of Pearl Harbor", Admiral Chester Nimitz, who became Commander in Chief of the Pacific Fleet, was later to say. "We had about of oil out there and all of it was vulnerable to .50 caliber bullets. Had the Japanese destroyed the oil," he added, "it would have prolonged the war another two years."
U.S.
Early in 1944, William Boyd, president of the American Petroleum Institute and chairman of the Petroleum Industry War Council said: "The Allies may have floated to victory on a wave of oil in World War I, but in this infinitely greater World War II, we are flying to victory on the wings of petroleum". In December 1941 the U.S. had 385,000 oil wells producing barrels of oil a year and 100-octane aviation gasoline capacity was at a day. By 1944, the U.S. was producing over a year (67 percent of world production) and the petroleum industry had built 122 new plants for the production of 100-octane aviation gasoline and capacity was over a dayan increase of more than ten-fold. It was estimated that the U.S. was producing enough 100-octane aviation gasoline to permit the dropping of () of bombs on the enemy every day of the year. The record of gasoline consumption by the Army prior to June 1943 was uncoordinated as each supply service of the Army purchased its own petroleum products and no centralized system of control nor records existed. On 1 June 1943, the Army created the Fuels and Lubricants Division of the Quartermaster Corps, and, from their records, they tabulated that the Army (excluding fuels and lubricants for aircraft) purchased over of gasoline for delivery to overseas theaters between 1 June 1943 through August 1945. That figure does not include gasoline used by the Army inside the U.S. Motor fuel production had declined from in 1941 down to in 1943. World War II marked the first time in U.S. history that gasoline was rationed and the government imposed price controls to prevent inflation. Gasoline consumption per automobile declined from per year in 1941 down to in 1943, with the goal of preserving rubber for tires since the Japanese had cut the U.S. off from over 90 percent of its rubber supply which had come from the Dutch East Indies and the U.S. synthetic rubber industry was in its infancy. Average gasoline prices went from a record low of ( with taxes) in 1940 to ( with taxes) in 1945.
Even with the world's largest aviation gasoline production, the U.S. military still found that more was needed. Throughout the duration of the war, aviation gasoline supply was always behind requirements and this impacted training and operations. The reason for this shortage developed before the war even began. The free market did not support the expense of producing 100-octane aviation fuel in large volume, especially during the Great Depression. Iso-octane in the early development stage cost , and, even by 1934, it was still compared to for motor gasoline when the Army decided to experiment with 100-octane for its combat aircraft. Though only three percent of U.S. combat aircraft in 1935 could take full advantage of the higher octane due to low compression ratios, the Army saw that the need for increasing performance warranted the expense and purchased 100,000 gallons. By 1937, the Army established 100-octane as the standard fuel for combat aircraft and by 1939 production was only a day. In effect, the U.S. military was the only market for 100-octane aviation gasoline and as war broke out in Europe this created a supply problem that persisted throughout the duration.
With the war in Europe a reality in 1939, all predictions of 100-octane consumption were outrunning all possible production. Neither the Army nor the Navy could contract more than six months in advance for fuel and they could not supply the funds for plant expansion. Without a long-term guaranteed market, the petroleum industry would not risk its capital to expand production for a product that only the government would buy. The solution to the expansion of storage, transportation, finances, and production was the creation of the Defense Supplies Corporation on 19 September 1940. The Defense Supplies Corporation would buy, transport and store all aviation gasoline for the Army and Navy at cost plus a carrying fee.
When the Allied breakout after D-Day found their armies stretching their supply lines to a dangerous point, the makeshift solution was the Red Ball Express. But even this soon was inadequate. The trucks in the convoys had to drive longer distances as the armies advanced and they were consuming a greater percentage of the same gasoline they were trying to deliver. In 1944, General George Patton's Third Army finally stalled just short of the German border after running out of gasoline. The general was so upset at the arrival of a truckload of rations instead of gasoline he was reported to have shouted: "Hell, they send us food, when they know we can fight without food but not without oil." The solution had to wait for the repairing of the railroad lines and bridges so that the more efficient trains could replace the gasoline-consuming truck convoys.
U.S., 1946–present
The development of jet engines burning kerosene-based fuels during WWII for aircraft produced a superior performing propulsion system than internal combustion engines could offer and the U.S. military forces gradually replaced their piston combat aircraft with jet powered planes. This development would essentially remove the military need for ever increasing octane fuels and eliminated government support for the refining industry to pursue the research and production of such exotic and expensive fuels. Commercial aviation was slower to adapt to jet propulsion and until 1958, when the Boeing 707 first entered commercial service, piston powered airliners still relied on aviation gasoline. But commercial aviation had greater economic concerns than the maximum performance that the military could afford. As octane numbers increased so did the cost of gasoline but the incremental increase in efficiency becomes less as compression ratio goes up. This reality set a practical limit to how high compression ratios could increase relative to how expensive the gasoline would become. Last produced in 1955, the Pratt & Whitney R-4360 Wasp Major was using 115/145 Aviation gasoline and producing at 6.7 compression ratio (turbo-supercharging would increase this) and of engine weight to produce . This compares to the Wright Brothers engine needing almost of engine weight to produce .
The U.S. automobile industry after WWII could not take advantage of the high octane fuels then available. Automobile compression ratios increased from an average of 5.3-to-1 in 1931 to just 6.7-to-1 in 1946. The average octane number of regular-grade motor gasoline increased from 58 to 70 during the same time. Military aircraft were using expensive turbo-supercharged engines that cost at least 10 times as much per horsepower as automobile engines and had to be overhauled every 700 to 1,000 hours. The automobile market could not support such expensive engines. It would not be until 1957 that the first U.S. automobile manufacturer could mass-produce an engine that would produce one horsepower per cubic inch, the Chevrolet 283 hp/283 cubic inch V-8 engine option in the Corvette. At $485, this was an expensive option that few consumers could afford and would only appeal to the performance-oriented consumer market willing to pay for the premium fuel required. This engine had an advertised compression ratio of 10.5-to-1 and the 1958 AMA Specifications stated that the octane requirement was 96–100 RON. At (1959 with aluminum intake), it took of engine weight to make .
In the 1950s, oil refineries started to focus on high octane fuels, and then detergents were added to gasoline to clean the jets in carburetors. The 1970s witnessed greater attention to the environmental consequences of burning gasoline. These considerations led to the phasing out of TEL and its replacement by other antiknock compounds. Subsequently, low-sulfur gasoline was introduced, in part to preserve the catalysts in modern exhaust systems.
Explanatory notes
References
Bibliography
Gold, Russell. The Boom: How Fracking Ignited the American Energy Revolution and Changed the World (Simon & Schuster, 2014).
Yergin, Daniel. The Quest: Energy, Security, and the Remaking of the Modern World (Penguin, 2011).
Yergin, Daniel. The Prize: The Epic Quest for Oil, Money, and Power (Buccaneer Books, 1994; latest edition: Reissue Press, 2008).
Graph of inflation-corrected historic prices, 1970–2005. Highest in 2005
The Low-Down on High Octane Gasoline
External links
Images
Down the Gasoline Trail Handy Jam Organization, 1935 (Cartoon)
IARC Group 2B carcinogens
Inhalants
Liquid fuels
Petroleum products | History of gasoline | [
"Chemistry"
] | 7,627 | [
"Petroleum",
"Petroleum products"
] |
78,178,032 | https://en.wikipedia.org/wiki/ImKTX58 | ImKTX58 (also known as kappa-Buthitoxin-Im1a) is a peptide toxin from the venom of the scorpion species Isometrus maculatus (also known as the lesser brown scorpion). It is known for its selective inhibition of Kv1.3 channels, on which it acts as a pore-blocker.
Etymology
The name of ImKTX58 stems from its origin in the scorpion species Isometrus maculatus (Im), its action on potassium channels (K), its categorization as a toxin (TX), and its identification as the 58th clone in the Isometrus maculatus cDNA library (58). The protein is also referred to as kappa-Buthitoxin-Im1a, in line with the rational nomenclature system used for toxins produced by venomous species.
Source
ImKTX58 is derived from the venom secreted by the glands of Isometrus maculatus (also known as the lesser brown scorpion) which belongs to the Buthidae family. It was first reported from Isometrus maculatus specimens found in Hainan, China.
Chemistry
Structure
The entire cDNA of ImKTX58 comprises 404 base pairs and codes for a 60 amino acid precursor, including a signal peptide of 22 amino acids. The mature ImKTX58 protein consists of 38 amino acid residues and has a molecular mass of 4370.14 Da. It features an α-helix at the N-terminus and β-sheet framework at the C-terminus reinforced by cysteine residues and three disulfide bridges, which contribute to its stability.
Amino acid sequence of the mature protein: QVHTKIMCSVSRECYEPCHGVTGRAHGKCMNKKCTCYW.
Family and homology
ImKTX58 is a small polypeptide toxin from the α-KTX subfamily. It shares sequence homology with other potassium channel blockers from the same subfamily, such as LmKTX10 (74% similarity) and ImKTX88 (54% similarity).
Target and channel specificity
ImKTX58 is a potent selective blocker of the Kv1.3 channel, which is a voltage-gated potassium channel essential in regulating neuronal excitability, and in the activation and proliferation of effector memory T cells. Electrophysiological recordings show that ImKTX58 effectively inhibits Kv1.3-mediated currents in Jurkat T cells (IC50 = 39.41 ± 11.4 nM) and HEK293T cells (IC50 = 10.42 ± 1.46 nM).
Moreover, ImKTX58 demonstrates a high selectivity for the Kv1.3 channel over other voltage-gated potassium channels, such as Kv1.1, Kv1.2, Kv1.5, as well as calcium-activated potassium channels SK2, SK3, BK, and voltage-gated sodium channels Nav1.4, Nav1.5, Nav1.7.
Mode of action
ImKTX58 exerts a partially reversible pore-blocking effect by forming a protein complex with Kv1.3 channels. The amino acid residues at the C-terminus of the toxin, specifically Lys28, Asn31, Arg24, and Tyr37, are significant for the interaction between ImKTX58 and Kv1.3 channels. These residues act through mechanisms such as hydrogen bonding, salt bridges, and hydrophobic interactions. In particular, the Lys28 residue is crucial for effectively blocking the pore of the Kv1.3 channel. This pore blockage leads to increased cellular excitability, ultimately disrupting the regulation of the cell membrane potential. In neurons with higher Kv1.3 expression this results in a higher frequency of action potentials, a slight reduction in their amplitude, and a modest depolarization.
Toxicity
The toxicity of ImKTX58 has not been thoroughly characterized. However, Isometrus maculatus has been identified as a species with venom of relatively weak overall toxicity.
References
Ion channel toxins
Neurotoxins
Scorpion toxins | ImKTX58 | [
"Chemistry"
] | 862 | [
"Neurochemistry",
"Neurotoxins"
] |
78,178,291 | https://en.wikipedia.org/wiki/Hg1%20%28toxin%29 | Hg1 (also known as Delta-Ktx 1.1) is a Kunitz-type peptide ion channel toxin derived from the scorpion Hadrurus gertschi. Its mode of action is that it selectively inhibits the potassium channel Kv1.3 and, with a lower affinity, channels Kv1.1 and Kv1.2.
Etymology and source
The Hg1 toxin is named after the Mexican scorpion Hadrurus gertschi that produces it, which belongs to the Caraboctonidae family. This scorpion is also known as Hoffmannihadrurus gertschi. The alternative name of Hg1 is Delta-Ktx 1.1.
Chemistry
Hg1 has a sequence of 88 amino acids with three disulfide bonds between Cys29-Cys79, Cys38-Cys62 and Cys54-Cys75. Hg1 has a molecular weight of 9,855 Da. It belongs to the Kunitz-type potassium channel family toxins. These toxins are classified in three different groups, according to their disulfide bridge pattern. Hg1 is classified as a member of the first group, showing classical disulfide pairing, comparable to the HWTX-XI toxin in spiders, dendrotoxin K in snakes, and APEKTx1 in sea anemones.
Amino acid sequence
MIIFYGLFSILVLTSINIAEAGHHNRVNCLLPPKTGPCKGSFARYYFDIETGSCKAFIYGGCEGNSNNFSEKHHCEKRCRGFRKFGGK
Target
The toxin primarily inhibits voltage-gated potassium channels and is highly selective for channel Kv1.3 with an IC50 of 6.2 ± 1.2 nM. With a lower affinity the toxin also inhibits potassium channels Kv1.1 and Kv1.2.
Similar to other Kunitz-type toxins, recombinant Hg1 was revealed to inhibit the serine protease trypsin (dissociation constant (Kd) = 107 nM), having the highest affinity to it compared to other Kunitz-type potassium channel toxins, such as LmKTT-1a (Kd = 140 nM), LmKTT-1b (Kd = 160 nM), LmKTT-1c (Kd = 124 nM), and BmKTT-1 (Kd = 136 nM).
Mode of action
Compared to other Kunitz-type toxins that act on potassium channels through their N-terminal regions, alanine-scanning supports that the Hg1 toxin interacts with the Kv1.3 channel through its residues on the C-terminal region. Based on computational modelling, the toxin is thought to inhibit the channel through pore-blocking mechanisms of its Lys-56 residue and hydrophobic interactions between residues of the toxin (Arg-57, Phe-61, Lys-63) and residues of the Kv1.3 channel.
References
Ion channel toxins
Scorpion toxins
Peptides | Hg1 (toxin) | [
"Chemistry"
] | 636 | [
"Biomolecules by chemical classification",
"Peptides",
"Molecular biology"
] |
78,178,299 | https://en.wikipedia.org/wiki/Manoj%20Kumar%20Mishra | Manoj Kumar Mishra (born 15 October 1952) is an Indian academic and researcher. He served as the 37th vice-chancellor of the University of Lucknow. He is recognised for his work in quantum chemistry.
Mishra completed his education at the St. Xavier's College, IIT Delhi and the University of Florida. He then completed a postdoctoral fellowship at Princeton University.
Mishra has held academic positions, including vice chancellor of Lucknow University (2009–2012), and also served in leadership roles at IIT Bombay.
He has won the M.N. Saha Award for theoretical sciences and the S.C. Bhattacharya Award for Excellence in Pure Sciences.
Academic and teaching career
Mishra began his career in academia after a postdoctoral research associateship at Princeton University, USA. He joined the Indian Institute of Technology (IIT) Bombay as a faculty member, where he spent 27 years in various capacities, including head of the Department of Chemistry and chairman of the Graduate Aptitude Test in Engineering (GATE) from June 2008 to July 2009. He served as the vice chancellor of the University of Lucknow, from 21 October 2009 to 2 November 2012. Since November 22, 2013, he has been vice chancellor of BIT Mesra, Ranchi.
Legacy
Mishra became a Fellow of the Indian Academy of Sciences in 1999. He was elected to the National Academy of Sciences, India,
References
1952 births
Indian academics
Indian theoretical chemists
Saint Xavier University alumni
University of Florida alumni
Living people | Manoj Kumar Mishra | [
"Chemistry"
] | 302 | [
"Indian theoretical chemists",
"Theoretical chemists"
] |
78,178,313 | https://en.wikipedia.org/wiki/Galileo%20Solar%20Space%20Telescope | Galileo Solar Space Telescope – Multi-mission Platform (GSST-PMM) is a mission proposed by Brazil's National Institute for Space Research (INPE) that aims to precisely measure the solar radiation at the top of the Earth's atmosphere, the magnetic field in the photosphere and the upper solar atmosphere.
Mission
Development
The project was initiated in November 2013 following an opportunity call from the Advisory Committee of the INPE's General Coordination of Space and Atmospheric Sciences. The first project was a prototype of a spectropolarimetry-based instrument that aimed to estimate the Sun's magnetic field. The Advisory Committee held several evaluation meetings between 2014 and 2018.
The mission planning initially consisted of three phases:
Development of a magnetograph and a visible light imaging instrument;;
Installation of a prototype instrument in a ground observatory;
Development of the space observatory;
It was also proposed the development of a prototype for testing in a balloon, but this stage was eventually eliminated.
INPE's Integrated Space Mission Project Center accepted the proposal after initial contact in December 2016. Analysis of the mission began in June 2017, with the study being presented in December of the same year. The feasibility study report was released in May 2018 and following this, the Working Group began discussing the GSST with both the scientific community and decision-makers.
The concept phase prototype, using a 150 mm telescope, was completed in July 2018. The advanced prototype had a 500 mm telescope. Initially, a workshop was to be held in March 2020 to discuss the mission with the international community, but it was canceled due to the COVID-19 pandemic. In the second half of 2020, after the restructuring of INPE, the continuity of the project was discussed, and the use of the , used in the Amazônia 1 satellite, was proposed and validated.
ProSAME
On May 8, 2023, the project was presented to the AEB and on May 19, the necessary documents were submitted for the Admission Card of the Procedure for Selection and Adoption of Space Missions (ProSAME) of the Brazilian Space Agency (AEB).
After several steps had been taken, on September 21, Dr. Clezio Marcos de Nardin, director of INPE, sent a letter to the president of the Brazilian Space Agency, making the adoption of GSST conditional on the installation and operation of a 500 mm ground telescope at the Pico dos Dias Observatory for two uninterrupted years, which, according to researcher and principal investigator Luís Eduardo Antunes Vieira, would interrupt the continuity of the project and would not have the slightest technical basis, as the ground and space instruments are different pieces of equipment: the ground equipment uses visible light, while the space equipment will operate in the ultraviolet, in addition to the Earth's rotation and climatic conditions making uninterrupted use impossible. The installation of the telescope on Pico dos Dias was never 100% necessary, and was only considered for the equipment to continue to be useful. The initial meeting between INPE and the to install the equipment at Pico dos Dias took place on September 28, 2023. It was later discovered that Dr. Clezio Nardin had not sent the complete documentation to the AEB.
Researcher Luis Vieira aimed to draw the attention of the international community with his Request for Support, also creating an online petition. As a result, at a meeting on December 7, 2023, the GSST Mission was officially approved in the AEB Qualification Portfolio.
Objectives
GSST aims to measure, precisely, the solar irradiance at the top of the Earth's atmosphere, the magnetic field in the photosphere and in the upper layers of the solar atmosphere, as well as addressing various processes that act on the Sun, with an understanding of the solar irradiance at the top of the Earth's atmosphere being fundamental to understanding climate change.
According to researcher Luís Eduardo Antunes Vieira, the GSST is a pioneering mission in the Brazilian space program, aiming to carry out high-resolution observations, which will seek to answer the following questions: “What is the influence of solar activity on the Earth's climate? What are the fundamental physical processes taking place on the Sun? How does the solar dynamo work? What are the relative contributions of the different physical processes that lead to the heating of the outer layers of the solar atmosphere (chromosphere to corona)? What effect does the variable structure of the solar magnetic field have on the evolution of the Earth's atmosphere-ocean coupled system? What are the responses of magnetic fields and energetic particles in the vicinity of the Earth due to the different structures of the solar wind?”.
By combining the data from this mission with data from NASA, ESA and JAXA missions, GSST will improve the development of INPE's space weather products and services. It is proposed that the telescope will be in an orbit 601.599 km above the equator, with an inclination of 97.749˚, being considered a Low Earth orbit, geostationary or heliosynchronous, needing total visibility of the solar disk for 90% of the time of a mission expected to last five years. The satellite is planned to be deorbited 25 years after the end of the main mission.
Payload
In the mission's study report, published in 2018, the following equipment was proposed:
A high-resolution UV/VIS camera and a low-resolution camera to observe the solar disk as a way of understanding the evolution of the magnetic structures of the Sun's outer layer;
A radiometer to understand the Sun's influence on the Earth's climate;
An electron and proton detector, as well as a magnetometer, to understand the Sun's influence on geospace.
See also
List of Brazilian satellites
List of proposed space telescopes
Reference
Bibliography
Primary sources
News
Scientific articles
Additional reading
Satellites of Brazil
Solar space observatories
Proposed space probes | Galileo Solar Space Telescope | [
"Astronomy"
] | 1,211 | [
"Space telescopes",
"Solar space observatories"
] |
78,178,579 | https://en.wikipedia.org/wiki/Reinhold%20Einwallner | Reinhold Einwallner (born 13 May 1973) is an Austrian politician and member of the National Council. A member of the Social Democratic Party, he has represented Vorarlberg since November 2017. He was a member of the Landtag of Vorarlberg from October 2014 to October 2017 and a member of the Federal Council from October 2004 to October 2009.
Einwallner was born on 13 May 1973 in Bruck an der Mur. He trained to be an optician at a vocational school from 1988 to 1992 before studying optometry at a higher technical college in Hall in Tirol from 1994 to 1997. He has been working as an optician since 1997 and has owned his own business since 2003. He was a member of the municipal councils in Hörbranz (2000 to 2015) and Bregenz (since 2020). He has held various positions in the Social Democratic Party (SPÖ)'s Vorarlberg branch and at the federal level.
Einwallner was appointed to the Federal Council by the Landtag of Vorarlberg following the 2004 state election. He was elected to the Landtag of Vorarlberg at the 2014 state election. He was elected to the National Council at the 2017 legislative election.
Einwallner is married and has one child.
References
External links
1973 births
Living people
Members of the 26th National Council (Austria)
Members of the 27th National Council (Austria)
Members of the Federal Council (Austria)
Members of the Landtag of Vorarlberg
Opticians
People from Bregenz
Social Democratic Party of Austria politicians | Reinhold Einwallner | [
"Astronomy"
] | 316 | [
"Opticians",
"History of astronomy"
] |
78,178,811 | https://en.wikipedia.org/wiki/Hefer%27s%20theorem | In several complex variables, Hefer's theorem is a result that represents the difference at two points of a holomorphic function as the sum of the products of the coordinate differences of these two points with other holomorphic functions defined in the Cartesian product of the function's domain.
The theorem bears the name of Hans Hefer. The result was published by Karl Stein and Heinrich Behnke under the name Hans Hefer. In a footnote in the same article, it is written that Hans Hefer died on the eastern front and that the work was an excerpt from Hefer's dissertation which he defended in 1940.
Statement of the theorem
Let be a domain of holomorphy and be a holomorphic function. Then, there exist holomorphic functions defined on so that
holds for every .
The decomposition in the theorem is feasible also on many non-pseudoconvex domains.
Hefer's lemma
The proof of the theorem follows from Hefer's lemma.
Let be a domain of holomorphy and be a holomorphic function. Suppose that is identically zero on the intersection of with the -dimensional complex coordinate space; i.e.
.
Then, there exist holomorphic functions defined on so that
holds for every .
References
Several complex variables
Theorems in complex analysis | Hefer's theorem | [
"Mathematics"
] | 276 | [
"Theorems in mathematical analysis",
"Functions and mappings",
"Several complex variables",
"Theorems in complex analysis",
"Mathematical objects",
"Mathematical relations"
] |
78,179,351 | https://en.wikipedia.org/wiki/RPRFamide | RPRFamide is a neurotoxin belonging to the conorfamide family of neuropeptides, which can be found in the venom of cone snails.
Etymology and source
RPRFamide is a toxin from the carnivorous marine cone snail Conus textile, a predatory species that mainly lives in tropical waters. The venom of marine cone snails contains a diverse variety of toxins, which include conotoxins.
RPRFamide belongs to the family of conotoxins, more specifically to the conorfamide family or RFamide family which are peptides that target neuronal ion channels in their prey.
Chemistry
The sequence for this toxin is identified as RPRF (R = arginine, P = proline, and F = phenylalanine). An amide group (-NH2) is located at the terminal end (C-terminus). The presence of this group is paramount for its biological activity as it enhances its interaction with ion channels.
The short length, the C-terminal Arg–Phe–NH2 (RFa) motif, and the lack of cysteines clearly distinguishes these peptides from conotoxins and categorises them as cono-RFamides.
Target
Two main molecular targets have been discovered for RPRFamide. Firstly, it targets the acid sensing ion channel 3 (ASIC3), involved in the pain pathway. Secondly, it can target and inhibit nicotinic acetylcholine receptors (nAChRs), specifically the alpha-7 subtype.
Mode of action
The RPRFamide peptide modulates ASIC3, a proton-gated ion channel that is sensitive to acidic conditions and involved in pain perception. This channel is a proton-gated sodium channel involved in nociception in response to acidic environments in a tissue, such as muscle fatigue. The toxin enhances ASIC3 currents, leading to increased pain signalling, particularly in response to acidic stimuli. This explains why RPRFamide can induce pain, particularly muscle pain, through the activation of ASIC3 channels. The peptide delays the desensitization of ASIC3 channels, keeping them open longer and allowing sustained ion flow, which increases sensitivity to pain stimuli and prolongs the nociceptive effect.
Studies show that injecting cono-RFamide into mice muscle leads to increased acid induced pain. Additionally, studies showed that RPRFamide causes an increase in excitability of dorsal root ganglion (DRG) neurons.
The RPRFamide also modulates nACh receptors by inhibiting them, specifically the alpha-7 and muscle-type nAChRs. These receptors are ligand-gated ion channels that mediate fast synaptic transmission in the nervous system and are involved in neuromuscular function. The toxin's inhibitory effect prevents the influx of ions that would normally result from acetylcholine binding, disrupting neurotransmission and impairing muscle contraction, depending on the receptor subtype.
Toxicity
The toxicity of RPRFamide has yet to be assessed in humans. However, available literature suggests that ASIC3 channels are expressed in muscle pain receptors, leading to extreme, long-lasting pain when injected into muscle tissue in mice, particularly when administered with an acidic solution.
Treatment
Currently, no available literature describes a method to counteract the neurotoxic activity of RPRFamide.
Therapeutic use
The therapeutic potential of RPRFamide has yet to be fully assessed. Some authors have discussed the neurotoxin's modulation of ASIC3 and nAChRs receptors, suggesting that further research could explore its role in pain modulation, including potential treatments for chronic pain.
References
Ion channel toxins
Neurotoxins
Snail toxins
Tetrapeptides
Amides | RPRFamide | [
"Chemistry"
] | 790 | [
"Neurotoxins",
"Neurochemistry",
"Amides",
"Functional groups"
] |
78,179,899 | https://en.wikipedia.org/wiki/JNJ-37654032 | JNJ-37654032 is a selective androgen receptor modulator (SARM) which was developed by Johnson & Johnson for the potential treatment of muscular atrophy but was never marketed.
The drug is a nonsteroidal androgen receptor (AR) modulator with mixed agonistic (androgenic) and antagonistic (antiandrogenic) effects. In animals, it has shown full agonist-like effects in muscle, agonistic suppressive effects on follicle-stimulating hormone (FSH) secretion, and antagonistic or partially agonistic effects in the prostate. It was the lead compound of a novel benzimidazole series of SARMs described as being reminiscent of but distinct from the arylpropionamides (e.g., enobosarm).
JNJ-37654032 did not advance past the preclinical research and was never tested in humans. It was first described in the scientific literature by 2008.
References
Abandoned drugs
Benzimidazoles
Chloroarenes
Experimental sex-hormone agents
Trifluoromethyl compounds
Selective androgen receptor modulators | JNJ-37654032 | [
"Chemistry"
] | 240 | [
"Pharmacology",
"Drug safety",
"Medicinal chemistry stubs",
"Pharmacology stubs",
"Abandoned drugs"
] |
78,180,216 | https://en.wikipedia.org/wiki/JNJ-26146900 | JNJ-26146900 is a selective androgen receptor modulator (SARM) which was developed by Johnson & Johnson for the potential treatment of prostate cancer but was never marketed.
Description
The drug is a nonsteroidal androgen receptor (AR) modulator with mixed agonistic (androgenic) and antagonistic (antiandrogenic) effects. In animals, it partially prevents castration-induced loss of body weight, lean body mass (LBM), and bone (osteopenia or osteoporosis) and reduces prostate weight and prostate tumor growth. The nonsteroidal antiandrogen bicalutamide was also effective in partially preventing castration-induced loss of body weight and lean body mass, suggesting that it too may have some SARM-like activity in certain tissues. However, neither JNJ-26146900 nor bicalutamide were as effective as dihydrotestosterone (DHT) in terms of these effects. Based on the preceding findings, JNJ-26146900 shows a profile of androgenic and anabolic effects in muscle and bone but antiandrogenic effects in the prostate.
The drug is a novel indole derivative SARM and is structurally related to JNJ-37654032.
JNJ-26146900 did not advance past the preclinical research and was never tested in humans. It was first described in the scientific literature by 2007.
See also
JNJ-28330835
References
Abandoned drugs
Experimental sex-hormone agents
Indoles
Nitriles
Organosulfur compounds
Selective androgen receptor modulators
Trifluoromethyl compounds | JNJ-26146900 | [
"Chemistry"
] | 350 | [
"Organosulfur compounds",
"Drug safety",
"Functional groups",
"Organic compounds",
"Nitriles",
"Abandoned drugs"
] |
78,180,383 | https://en.wikipedia.org/wiki/GTx-027 | GTx-027 is a selective androgen receptor modulator (SARM) which was under development for or of potential interest in the treatment of breast cancer and stress urinary incontinence (SUI) but was never marketed. It is taken by mouth.
Description
The drug is a nonsteroidal androgen receptor (AR) modulator with mixed agonistic (androgenic) and antagonistic (antiandrogenic) effects. It has been found to reduce the growth of androgen receptor-expressing MDA-MB-231 breast cancer cells in vitro. In addition, it has been found to increase pelvic floor muscle weight in ovariectomized female rodents. The drug has been found to increase body weight, lean body mass, and muscle strength in animals as well. In terms of chemical structure, GTx-027 is a nonsteroidal arylpropionamide SARM and is an analogue of enobosarm (ostarine; GTx-024).
GTx-027 was first described in the scientific literature by 2013. It is said to have either not passed preclinical research or to have reached phase 1 clinical trials prior to the discontinuation of its development. The drug was developed by GTx.
References
Abandoned drugs
Amides
Chloroarenes
Cyano compounds
Experimental sex-hormone agents
Selective androgen receptor modulators | GTx-027 | [
"Chemistry"
] | 293 | [
"Amides",
"Drug safety",
"Functional groups",
"Abandoned drugs"
] |
78,180,685 | https://en.wikipedia.org/wiki/MK-4541 | MK-4541 is a dual selective androgen receptor modulator (SARM) and 5α-reductase inhibitor (5α-RI) which has been of interest for the potential treatment of prostate cancer but has not been marketed at this time. It is intended for use by mouth.
The drug is a steroidal androgen receptor (AR) modulator with mixed agonistic (androgenic) and antagonistic (antiandrogenic) effects. In preclinical research and animal studies, MK-4541 has been found to have androgenic or anabolic effects in muscle and bone, to strongly suppress testosterone levels (likely via androgenic antigonadotropic effects), and to have antiandrogenic effects in the prostate and in prostate cancer cells. Structurally, it is specifically a 4-azasteroid derivative.
MK-4541 was first described in the scientific literature by 2014. It was identified by screening of 3,000 compounds that were manually designed and predicted to have SARM activity. The drug was developed by Merck. It might be being developed for potential medical use, but its developmental status has not been publicly disclosed. In any case, MK-4541 is not known to have advanced past preclinical studies as of 2020.
See also
Cl-4AS-1
MK-0773
TFM-4AS-1
YK-11
References
5α-Reductase inhibitors
Abandoned drugs
Androstanes
Carbamates
Drugs developed by Merck & Co.
Experimental sex-hormone agents
Selective androgen receptor modulators | MK-4541 | [
"Chemistry"
] | 327 | [
"Pharmacology",
"Drug safety",
"Medicinal chemistry stubs",
"Pharmacology stubs",
"Abandoned drugs"
] |
78,181,317 | https://en.wikipedia.org/wiki/RG-7410 | RG-7410 is a trace amine-associated receptor 1 (TAAR1) agonist which was under development for the treatment of schizophrenia but was never marketed. Its route of administration was unspecified.
The drug reached phase 1 clinical trials prior to the discontinuation of its development. It was under development by Hoffmann-La Roche. RG-7410 was first disclosed by January 2014 and a phase 1 trial was reported to have been completed by October 2014.
See also
Ralmitaront (RG-7906; RO-6889450)
RG-7351
Ulotaront (SEP-363856; SEP-856)
References
Abandoned drugs
Drugs with undisclosed chemical structures
Experimental antidepressants
TAAR1 agonists | RG-7410 | [
"Chemistry"
] | 161 | [
"Drug safety",
"Abandoned drugs"
] |
78,182,178 | https://en.wikipedia.org/wiki/Gyulbudaghian%27s%20Nebula | Gyulbudaghian's Nebula (gyool-boo-DAH-ghee-an) is a reflection nebula in the northern constellation Cepheus, located about 1.5 degrees west of the much brighter reflection nebula NGC 7023. The light illuminating it comes from the T Tauri star PV Cephei. It is known for changing its shape dramatically on a timescale of months to years, as the brightness of PV Cephei changes. The nebula, whose magnitude ranges from 13.4 to 18.5, is far too faint to be seen with the naked eye, or even a small telescope. However, because of its changing morphology, it has become a target for observations by advanced amateur astronomers.
Gyulbudaghian's Nebula was discovered in 1977 by Armenian astronomers Armen Gyul'budaghian and Tigran Yu. Magakian at the Byurakan Astrophysical Observatory and separately that same year by Martin Cohen, Leonard Vello Kuhi and Eugene A. Harlan in California. Both groups discovered the nebula on the red Palomar Sky Survey (POSS) plates taken in 1952. Gyul'budaghian's group discovered the nebula's variable nature from followup observations with the 2.6 meter Byurakan reflector, and Cohen's group discovered its variability by comparing the POSS images with images of the region taken over a five-year period at Lick Observatory. It was found that the nebula sometimes appeared as a streak, and at other times it was shaped like a fan with PV Cephei at its tip. Subsequent studies have shown that sometimes the nebula disappears nearly completely.
In 1986 Scarrott et al. reported that Gyulbudaghian's Nebula is either bipolar or biconical. In addition to the fan shaped nebulousity to the north of PV Cephei, seen by earlier observers, they detected a fainter counterlobe south of the star. From polarization measurements they concluded that the bright north lobe is not reflected light, but rather intrinsic emission. The faint southern counterlobe was later found to be quite red; it is brighter in the near-infrared than in visible light and is dimmed by at least 4 magnitudes of extinction in visible light. The streak, when it is visible, coincides with the eastern edge of the fan-shaped nebula.
References
External links
A movie showing the nebula changing shape made from Zwicky Transient Facility images
Cepheus (constellation)
Reflection nebulae | Gyulbudaghian's Nebula | [
"Astronomy"
] | 516 | [
"Constellations",
"Cepheus (constellation)"
] |
78,182,189 | https://en.wikipedia.org/wiki/ITI-1549 | ITI-1549 is a putatively non-hallucinogenic serotonin 5-HT2A receptor agonist which is under development for the treatment of mood disorders and other psychiatric disorders. In addition to acting at the serotonin 5-HT2A receptor, it is also an antagonist of the serotonin 5-HT2B receptor and an agonist of the serotonin 5-HT2C receptor. The drug's route of administration has not been specified.
Pharmacology
Pharmacodynamics
Serotonergic psychedelics like psilocybin and lysergic acid diethylamide (LSD) are agonists of the serotonin 5-HT2A receptor that activate both the β-arrestin and Gq signaling pathways. In 2023, activation of the Gq pathway, but not the β-arrestin pathway, was linked with the production of hallucinogenic-like effects, specifically the head-twitch response (HTR), in animals. Serotonin 5-HT2A receptor agonists are of interest for the potential treatment of psychiatric disorders like depression and anxiety, but the hallucinogenic effects of serotonergic psychedelics serve as a barrier and partial limiting factor in this regard.
ITI-1549 has high affinity for the serotonin 5-HT2A receptor (Ki = 10.2nM) and acts as a partial agonist of the β-arrestin pathway with an intrinsic activity of 72% (relative to α-methylserotonin). Conversely, unlike serotonergic psychedelics, ITI-1549 does not activate the Gq pathway. Hence, it is a biased agonist of the serotonin 5-HT2A receptor. In accordance with the preceding, ITI-1549 does not produce the HTR, a behavioral proxy of psychedelic effects, in animals. However, similarly to serotonergic psychedelics, ITI-1549 has been found to produce anxiolytic-like and prosocial effects in animals. Antidepressant-like and psychoplastogenic effects of ITI-1549 in animals have yet to be assessed or reported. In any case, various other non-hallucinogenic serotonin 5-HT2A receptor agonists selective for the β-arrestin pathway have been found to produce antidepressant-like effects in animals.
In addition to the serotonin 5-HT2A receptor, ITI-1549 has high affinity for the serotonin 5-HT2B receptor (Ki = 4.8nM). However, it acts as an antagonist of this receptor rather than as an agonist ( = 13.8nM). Based on these findings, continuous administration of ITI-1549 is not expected to pose a risk of cardiac valvulopathy. This is in contrast to many serotonergic psychedelics, which have been shown to act as potent serotonin 5-HT2B receptor agonists. ITI-1549 is additionally a potent agonist of the serotonin 5-HT2C receptor (Ki = 21nM; = 40nM).
Chemistry
The drug is a small molecule, but its chemical structure does not yet seem to have been disclosed. It is said to be chemically unrelated to existing plant-derived and synthetic serotonergic psychedelics. However, its structure was disclosed in a 2024 patent. It is structurally related to the atypical antipsychotic lumateperone.
Clinical trials
As of February 2024, ITI-1549 is in the preclinical stage of development for psychiatric disorders. A phase 1 clinical trial is being planned and is expected to commence in late 2024 or early 2025. The drug is under development by Intra-Cellular Therapies. ITI-1549 was first described in the scientific literature by 2023.
See also
List of investigational hallucinogens and entactogens
List of miscellaneous 5-HT2A receptor agonists
AAZ-A-154 (DLX-001)
BMB-201
References
5-HT2A agonists
5-HT2B antagonists
5-HT2C agonists
Biased ligands
Experimental antidepressants
Experimental non-hallucinogens
Experimental psychiatric drugs
Non-hallucinogenic 5-HT2A receptor agonists | ITI-1549 | [
"Chemistry"
] | 944 | [
"Biased ligands",
"Signal transduction"
] |
78,182,775 | https://en.wikipedia.org/wiki/ACD856 | ACD856, or ACD-856, is a tropomyosin receptor kinase TrkA, TrkB, and TrkC positive allosteric modulator which is under development for the treatment of Alzheimer's disease, depressive disorders, sleep disorders, and traumatic brain injuries. It is taken by mouth.
Pharmacology
The drug potentiates the tropomyosin receptor kinases TrkA, TrkB, and TrkC with values of 382nM, 295nM, and ~330nM, respectively. As a positive allosteric modulator of TrkA and TrkB, ACD856 potentiates the effects of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).
In addition to the tropomyosin receptor kinases, ACD856 is also a similarly potent positive allosteric modulator of certain other receptor tyrosine kinases, including the insulin-like growth factor 1 receptor (IGF1R) and the fibroblast growth factor receptor 1 (FGFR1). However, its efficacies at the IGF1R and FGFR1 were much lower than at the TrkA, TrkB, and TrkC.
In animals, ACD856 has been found to reverse scopolamine- and dizocilpine (MK-801)-induced memory impairment, to improve age-related memory deficits, and to have sustained antidepressant-like activity. It has also been reported to possess neuroprotective properties.
In humans, the drug has been shown to cross the blood–brain barrier and to induce dose-dependent changes in electroencephalogram parameters. No significant tolerability or safety concerns have been identified in preclinical research or phase 1 clinical trials. The drug's clinical pharmacokinetics have been characterized and its elimination half-life is approximately 19hours.
Chemistry
The chemical structure of ACD856 has not yet been disclosed as of 2024, but the structure of its predecessor ponazuril (ACD855) is known and both ponazuril and ACD856 have been described as triazinetriones.
History
It was discovered through the use of high-throughput screening of 25,000compounds. Toltrazuril and ponazuril (ACD855), two veterinary antiparasitic agents, were identified as possessing Trk-potentiating activity with this screen in 2013. ACD856 was derived via structural optimization of these compounds. In the case of ponazuril, this drug was said to have had too long of an elimination half-life to allow for development for use in humans. ACD856 was first described in the scientific literature by 2021.
Clinical trials
As of May 2024, ACD856 is in phase 1 clinical trials for Alzheimer's disease and is in the preclinical stage of development for depressive disorders, sleep disorders, and traumatic brain injuries. Two phase 1 trials have been completed. A phase 2 clinical trial for Alzheimer's disease is being planned as of May 2024. The drug is under development by AlzeCure Pharma AB.
References
Drugs with undisclosed chemical structures
Experimental antidepressants
Experimental drugs for Alzheimer's disease
Ketones
Neuroprotective agents
Receptor modulators
Triazines
TrkB agonists | ACD856 | [
"Chemistry"
] | 729 | [
"Ketones",
"Functional groups"
] |
78,183,783 | https://en.wikipedia.org/wiki/Isopropalin | Isopropalin is a herbicide. Introduced in 1969, it is a preëmergent selective dinitroaniline to control annual grasses and broadleaf weeds. Brought by DowElanco in 1972 to the US and Australia, it is now considered obsolete. In 1974, American farmers used of isopropalin.
Paarlan was a 69% isopropalin emulsifiable concentrate approved for use on tobacco. It required soil incorporation due to low solubility, ultraviolet light degradation and high volatilisation, and it may have been registered for white potatoes and tomatoes. Dow marketed Paarlan to southern culture, with a video advert claiming it "is just as much a part of tobacco country as ham and biscuits are part of breakfast."
Rats fed diets with large amounts of isopropalin had reduced hemoglobin concentrations, lowered hematocrits, and altered organ weights at the higher doses tested.
References
Links
Preemergent herbicides
Nitrotoluene derivatives
Anilines
Herbicides
Propyl compounds
Isopropyl compounds | Isopropalin | [
"Biology"
] | 222 | [
"Herbicides",
"Biocides"
] |
78,184,100 | https://en.wikipedia.org/wiki/Ammonium%20hexabromoplatinate | Ammonium hexabromoplatinate is an inorganic chemical compound with the chemical formula .
Physical properties
Ammonium hexabromoplatinate forms red-brown crystals.
It is poorly soluble in water.
References
Platinum compounds
Bromo complexes
Ammonium compounds
Bromometallates | Ammonium hexabromoplatinate | [
"Chemistry"
] | 59 | [
"Ammonium compounds",
"Salts"
] |
78,184,192 | https://en.wikipedia.org/wiki/KIC%209970396 | KIC 9970396 is an eclipsing binary system located in the northern constellation of Cygnus about distant. The system consists of a red-giant branch star and an F-type main-sequence star. The two stars orbit each other every at a mean distance of ( AU), almost the same as Earth's distance from the Sun.
The system was given the Kepler Object of Interest designation KOI-7606 as a planetary candidate, but has been marked a false positive since the dips in the light curve are caused by an eclipsing stellar companion rather than a transiting exoplanet.
Stellar components
KIC 9970396A
KIC 9970396A is a pulsating red giant currently in the red-giant branch, past the first dredge-up event and approaching the red giant bump. The star displays solar-like oscillations caused by turbulent convection near the surface. Since the star has used up all of its hydrogen within its core, the core now consists mostly of helium, with a mass of 0.229 , that is 19% of the star's entire mass, and a radius of 0.03055 . Its age is estimated at billion years, about 1.5 billion years older than the Solar System (4.568 Gyr).
KIC 9970396B
KIC 9970396B is a late F-type star almost identical in mass to the Sun but slightly larger and hotter. Its mass is slightly smaller than the red giant primary, thus a possible scenario for the system is that the two stars formed together and the more massive primary star evolved past the main sequence first.
Its stellar parameters, alongside those of the red giant, were precisely measured using a combination of Kepler photometry and spectroscopic observations.
References
Cygnus (constellation)
Kepler objects of interest
J19545035+4649589
Kepler Input Catalog
Eclipsing binaries
Red giants
F-type main-sequence stars | KIC 9970396 | [
"Astronomy"
] | 410 | [
"Cygnus (constellation)",
"Constellations"
] |
78,184,272 | https://en.wikipedia.org/wiki/GSX2 | GS homeobox 2 (GSX2) is a protein encoded by a gene of the same name, located on chromosome 4 in humans, and on chromosome 5 in mice.
It is especially important to regulating the development of the brain, particularly during embryonic development. Mutations have been linked to a variety of neurological disorders that can cause intellectual disability, dystonia (difficulty with movement) and seizures.
Structure
GSX2 is a polypeptide chain consisting of 304 amino acids, with a molecular weight of 32,031.
Function
GSX2 is a homeobox transcription factor essential for mammalian forebrain development, particularly in specifying and patterning the basal ganglia. It binds specific DNA sequences, crucial for dorsal-ventral patterning of the telencephalon and specifying neural progenitors in the ventral forebrain.
GSX2 acts within a temporal framework, initially guiding the specification of striatal projection neurons during early lateral ganglionic eminence (LGE) neurogenesis, and later supporting olfactory bulb interneuron development. Mutations in GSX2 have been linked to basal ganglia dysgenesis in humans, resulting in severe neurological symptoms, including dystonia and intellectual impairment.
GSX2 is highly expressed in neural progenitors within the ganglionic eminences, precursors to the basal ganglia and olfactory structures. It promotes neurogenesis while inhibiting differentiation into oligodendrocytes, a type of glial cell in the central nervous system.
Clinical significance
Neurodevelopmental disorders
Mutations in GSX2 have been linked to severe neurodevelopmental disorders characterized by specific brain malformations. This includes cases of basal ganglia agenesis, leading to symptoms such as a slowly progressive decline in neurologic function, dystonia, and intellectual impairment.
Diencephalic-mesencephalic junction dysplasia syndrome
A single nucleotide polymorphism and missense mutation in GSX2, rs1578004339, has been found to be a pathogenic cause of diencephalic-mesencephalic junction dysplasia syndrome, a neurodevelopmental disorder characterised by severe intellectual disability and seizures.
References
Genes on human chromosome 4
Developmental genes and proteins | GSX2 | [
"Biology"
] | 475 | [
"Induced stem cells",
"Developmental genes and proteins"
] |
65,245,542 | https://en.wikipedia.org/wiki/Doxy%20%28vibrator%29 | The Doxy is a brand of British-made wand vibrators. The Doxy was created in 2013 in response to the unavailability of the Hitachi Magic Wand in the United Kingdom. It has been described as the most powerful wand vibrator on the market.
, it is manufactured by CMG Leisure in Callington, in the county of Cornwall in the south of England.
References
External links
Vibrators
British brands
2013 establishments in the United Kingdom
Callington
Companies based in Cornwall | Doxy (vibrator) | [
"Biology"
] | 102 | [
"Behavior",
"Sexuality stubs",
"Sexuality"
] |
65,245,860 | https://en.wikipedia.org/wiki/Latino%20mammarenavirus | Latino mammarenavirus is a species of virus in the family Arenaviridae. Its host is Calomys callosus, and it was isolated in Bolivia.
References
Arenaviridae | Latino mammarenavirus | [
"Biology"
] | 41 | [
"Virus stubs",
"Viruses"
] |
65,245,992 | https://en.wikipedia.org/wiki/Mobala%20mammarenavirus | Mobala mammarenavirus is a species of virus in the genus Mammarenavirus. It was isolated from a species of Praomys rodents in the Central African Republic.
References
Arenaviridae | Mobala mammarenavirus | [
"Biology"
] | 45 | [
"Virus stubs",
"Viruses"
] |
65,246,095 | https://en.wikipedia.org/wiki/Cali%20mammarenavirus | Cali mammarenavirus is a species of virus in the family Arenaviridae.
References
Arenaviridae | Cali mammarenavirus | [
"Biology"
] | 25 | [
"Virus stubs",
"Viruses"
] |
65,247,071 | https://en.wikipedia.org/wiki/Syndromic%20testing | Syndromic testing is a process by which a healthcare provider simultaneously tests a patient for multiple pathogens with overlapping symptomology. This allows providers to order one test to see if patients are suffering from any one of multiple causes, rather than having to order a test for each potential underlying reason for the illness. It can be used with patients that are immunosuppressed, in hospital environments that have limited testing assets, or patients that could be suffering from any number of or combination of reasons for a specific syndrome, such as respiratory distress, gastroenteritis, bloodstream infections, or CNS infections. The test uses multi-panel syndromic assays that allow the simultaneous detection of a number of agents, increasing the accuracy of tests for microbial agents. The first multiplex panel for syndromic testing to be approved by the FDA received approval in 2008, and since, panels for several potential pathogens have been approved.
References
Blood tests | Syndromic testing | [
"Chemistry"
] | 195 | [
"Blood tests",
"Chemical pathology"
] |
65,247,290 | https://en.wikipedia.org/wiki/Parmentiera%20edulis | Parmentiera edulis may be a synonym of two separate plant species:
Parmentiera aculeata (Parmentiera edulis DC.), native to Mexico and Central America
Solanum tuberosum (Parmentiera edulis Raf.), the potato, cultivated worldwide | Parmentiera edulis | [
"Biology"
] | 66 | [
"Set index articles on plants",
"Set index articles on organisms",
"Plants"
] |
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