text stringlengths 11 320k | source stringlengths 26 161 |
|---|---|
Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission . Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons , the release of heat energy ( kinetic energy of the nuclei), and gamma rays . The two ... | https://en.wikipedia.org/wiki/Nuclear_fission_product |
A nuclear flask is a shipping container that is used to transport active nuclear materials between nuclear power station and spent fuel reprocessing facilities.
Each shipping container is designed to maintain its integrity under normal transportation conditions and during hypothetical accident conditions. They must pr... | https://en.wikipedia.org/wiki/Nuclear_flask |
The nuclear force (or nucleon–nucleon interaction , residual strong force , or, historically, strong nuclear force ) is a force that acts between hadrons , most commonly observed between protons and neutrons of atoms . Neutrons and protons, both nucleons, are affected by the nuclear force almost identically. Since prot... | https://en.wikipedia.org/wiki/Nuclear_force |
Nuclear fuel refers to any substance, typically fissile material, which is used by nuclear power stations or other nuclear devices to generate energy.
For fission reactors, the fuel (typically based on uranium ) is usually based on the metal oxide ; the oxides are used rather than the metals themselves because the oxi... | https://en.wikipedia.org/wiki/Nuclear_fuel |
The nuclear fuel cycle , also known as the nuclear fuel chain , describes the series of stages that nuclear fuel undergoes during its production, use, and recycling or disposal. It consists of steps in the front end , which are the preparation of the fuel, steps in the service period in which the fuel is used during re... | https://en.wikipedia.org/wiki/Nuclear_fuel_cycle |
Nuclear fusion is a reaction in which two or more atomic nuclei combine to form a larger nuclei, nuclei/ neutron by-products. The difference in mass between the reactants and products is manifested as either the release or absorption of energy . This difference in mass arises as a result of the difference in nuclear bi... | https://en.wikipedia.org/wiki/Nuclear_fusion |
Hybrid nuclear fusion–fission ( hybrid nuclear power ) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes.
The basic idea is to use high-energy fast neutrons from a fusion reactor to trigger fission in non- fissile fuels like U-238 or Th-232 . Each neutron can trigg... | https://en.wikipedia.org/wiki/Nuclear_fusion–fission_hybrid |
A nuclear gene is a gene whose DNA sequence is located within the cell nucleus of a eukaryotic organism. These genes are distinguished from extranuclear genes, such as those found in the genomes of mitochondria and chloroplasts , which reside outside the nucleus in their own organellar DNA. Nuclear genes encode the maj... | https://en.wikipedia.org/wiki/Nuclear_gene |
A nuclear isomer is a metastable state of an atomic nucleus , in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have half-lives of 10 −9 seconds or longer, 100 to 1000 times longer than the half-lives of the excited... | https://en.wikipedia.org/wiki/Nuclear_isomer |
The nuclear lamina is a dense (~30 to 100 nm thick) fibrillar network inside the nucleus of eukaryote cells . It is composed of intermediate filaments and membrane associated proteins . Besides providing mechanical support, the nuclear lamina regulates important cellular events such as DNA replication and cell division... | https://en.wikipedia.org/wiki/Nuclear_lamina |
A nuclear localization signal or sequence ( NLS ) is an amino acid sequence that 'tags' a protein for import into the cell nucleus by nuclear transport . [ 1 ] Typically, this signal consists of one or more short sequences of positively charged lysines or arginines exposed on the protein surface. [ 1 ] Different nuclea... | https://en.wikipedia.org/wiki/Nuclear_localization_sequence |
The nuclear magnetic moment is the magnetic moment of an atomic nucleus and arises from the spin of the protons and neutrons . It is mainly a magnetic dipole moment; the quadrupole moment does cause some small shifts in the hyperfine structure as well. All nuclei that have nonzero spin also have a nonzero magnetic mome... | https://en.wikipedia.org/wiki/Nuclear_magnetic_moment |
Nuclear magnetic resonance ( NMR ) is a physical phenomenon in which nuclei in a strong constant magnetic field are disturbed by a weak oscillating magnetic field (in the near field [ 1 ] ) and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This proc... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance |
Nuclear magnetic resonance chemical shift re-referencing is a chemical analysis method for chemical shift referencing in biomolecular nuclear magnetic resonance (NMR). [ 1 ] It has been estimated that up to 20% of 13C and up to 35% of 15N shift assignments are improperly referenced. [ 2 ] [ 3 ] [ 4 ] Given that the str... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_chemical_shift_re-referencing |
Nuclear magnetic resonance crystallography ( NMR crystallography ) is a method which utilizes primarily NMR spectroscopy to determine the structure of solid materials on the atomic scale. Thus, solid-state NMR spectroscopy would be used primarily, possibly supplemented by quantum chemistry calculations (e.g. density fu... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_crystallography |
Nuclear magnetic resonance decoupling (NMR decoupling for short ) is a special method used in nuclear magnetic resonance (NMR) spectroscopy where a sample to be analyzed is irradiated at a certain frequency or frequency range to eliminate or partially the effect of coupling between certain nuclei . NMR coupling refers... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_decoupling |
Nuclear magnetic resonance (NMR) in porous materials covers the application of using NMR as a tool to study the structure of porous media and various processes occurring in them. [ 1 ] This technique allows the determination of characteristics such as the porosity and pore size distribution, the permeability , the wate... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_in_porous_media |
Nuclear magnetic resonance quantum computing ( NMRQC ) [ 1 ] is one of the several proposed approaches for constructing a quantum computer , that uses the spin states of nuclei within molecules as qubits . The quantum states are probed through the nuclear magnetic resonances, allowing the system to be implemented as a ... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_quantum_computer |
A nuclear magnetic resonance spectra database is an electronic repository of information concerning Nuclear magnetic resonance (NMR) spectra . Such repositories can be downloaded as self-contained data sets or used online. The form in which the data is stored varies, ranging from line lists that can be graphically di... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_spectra_database |
Carbohydrate NMR spectroscopy is the application of nuclear magnetic resonance (NMR) spectroscopy to structural and conformational analysis of carbohydrates . This method allows the scientists to elucidate structure of monosaccharides , oligosaccharides , polysaccharides , glycoconjugates and other carbohydrate derivat... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_spectroscopy_of_carbohydrates |
Nucleic acid NMR is the use of nuclear magnetic resonance spectroscopy to obtain information about the structure and dynamics of nucleic acid molecules, such as DNA or RNA . It is useful for molecules of up to 100 nucleotides, and as of 2003, nearly half of all known RNA structures had been determined by NMR spectrosc... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_spectroscopy_of_nucleic_acids |
Nuclear magnetic resonance spectroscopy of proteins (usually abbreviated protein NMR ) is a field of structural biology in which NMR spectroscopy is used to obtain information about the structure and dynamics of proteins , and also nucleic acids , and their complexes. The field was pioneered by Richard R. Ernst and Kur... | https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_spectroscopy_of_proteins |
In biology , the nuclear matrix is the network of fibres found throughout the inside of a cell nucleus after a specific method of chemical extraction. According to some it is somewhat analogous to the cell cytoskeleton . In contrast to the cytoskeleton, however, the nuclear matrix has been proposed to be a dynamic stru... | https://en.wikipedia.org/wiki/Nuclear_matrix |
Nuclear matter is an idealized system of interacting nucleons ( protons and neutrons ) that exists in several phases of exotic matter that, as of yet, are not fully established. [ 2 ] It is not matter in an atomic nucleus , but a hypothetical substance consisting of a huge number of protons and neutrons held together b... | https://en.wikipedia.org/wiki/Nuclear_matter |
Nuclear medicine ( nuclear radiology , nucleology ), [ 1 ] [ 2 ] [ unreliable source ] is a medical specialty involving the application of radioactive substances in the diagnosis and treatment of disease . Nuclear imaging is, in a sense, radiology done inside out , [ citation needed ] because it records radiation emitt... | https://en.wikipedia.org/wiki/Nuclear_medicine |
An atomic battery , nuclear battery , radioisotope battery or radioisotope generator uses energy from the decay of a radioactive isotope to generate electricity . Like a nuclear reactor , it generates electricity from nuclear energy, but it differs by not using a chain reaction . Although commonly called batteries , a... | https://en.wikipedia.org/wiki/Nuclear_micro-battery |
In histo pathology , nuclear moulding , also nuclear molding , is conformity of adjacent cell nuclei to one another. [ 1 ]
It is a feature of small cell carcinomas and particularly useful for differentiation of small cell and non-small cell carcinomas, i.e. adenocarcinoma and squamous carcinoma . [ 2 ] | https://en.wikipedia.org/wiki/Nuclear_moulding |
In mathematics, nuclear operators are an important class of linear operators introduced by Alexander Grothendieck in his doctoral dissertation. Nuclear operators are intimately tied to the projective tensor product of two topological vector spaces (TVSs).
Throughout let X , Y , and Z be topological vector spaces (TVSs... | https://en.wikipedia.org/wiki/Nuclear_operator |
Nuclear organization refers to the spatial organization and dynamics of chromatin within a cell nucleus during interphase . There are many different levels and scales of nuclear organization.
At the smallest scale, DNA is packaged into units called nucleosomes , which compacts DNA about 7-fold. In addition, nucleosome... | https://en.wikipedia.org/wiki/Nuclear_organization |
Nuclear orientation , in nuclear physics , is the directional ordering of an assembly of nuclear spins with respect to some axis in space. [ 1 ] [ 2 ] It is one of the nuclear spectroscopy methods.
A nuclear level with spin in a magnetic field will divide into magnetic sub-levels with an energy spacing. [ 3 ] The popu... | https://en.wikipedia.org/wiki/Nuclear_orientation |
... | https://en.wikipedia.org/wiki/Nuclear_pasta |
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter .
Nuclear physics should not be confused with atomic physics , which studies the atom as a whole, including its electrons .
Discoveries in nuclear physi... | https://en.wikipedia.org/wiki/Nuclear_physics |
The nuclear protein in testis gene (i.e. NUTM1 gene) encodes (i.e. directs the synthesis of) a 1,132- amino acid protein termed NUT [ 1 ] that is expressed almost exclusively in the testes , ovaries , [ 2 ] and ciliary ganglion (i.e. a parasympathetic ganglion of nerve cells located just behind the eye). [ 3 ] NUT prot... | https://en.wikipedia.org/wiki/Nuclear_protein_in_testis_gene |
Nuclear quadrupole resonance spectroscopy or NQR is a chemical analysis technique related to nuclear magnetic resonance ( NMR ). Unlike NMR, NQR transitions of nuclei can be detected in the absence of a magnetic field , and for this reason NQR spectroscopy is referred to as " zero Field NMR ". The NQR resonance is medi... | https://en.wikipedia.org/wiki/Nuclear_quadrupole_resonance |
In nuclear physics and nuclear chemistry , a nuclear reaction is a process in which two nuclei , or a nucleus and an external subatomic particle , collide to produce one or more new nuclides . Thus, a nuclear reaction must cause a transformation of at least one nuclide to another. If a nucleus interacts with another nu... | https://en.wikipedia.org/wiki/Nuclear_reaction |
Nuclear reaction analysis (NRA) is a nuclear method of nuclear spectroscopy in materials science to obtain concentration vs. depth distributions for certain target chemical elements in a solid thin film. [ 1 ]
If irradiated with select projectile nuclei at kinetic energies E kin , target solid thin-film chemical eleme... | https://en.wikipedia.org/wiki/Nuclear_reaction_analysis |
Nuclear reactor physics is the field of physics that studies and deals with the applied study and engineering applications of chain reaction to induce a controlled rate of fission in a nuclear reactor for the production of energy. [ 1 ]
Most nuclear reactors use a chain reaction to induce a controlled rate of nuclear ... | https://en.wikipedia.org/wiki/Nuclear_reactor_physics |
Nuclear resonance fluorescence ( NRF ) is a nuclear process in which a nucleus absorbs and emits high-energy photons called gamma rays . NRF interactions typically take place above 1 MeV , and most NRF experiments target heavy nuclei such as uranium and thorium [ 1 ]
This process is used for scanning cargo for contrab... | https://en.wikipedia.org/wiki/Nuclear_resonance_fluorescence |
A nuclear run-on assay is conducted to identify the genes that are being transcribed at a certain time point. Approximately one million cell nuclei are isolated and incubated with labeled nucleotides , and genes in the process of being transcribed are detected by hybridization of extracted RNA to gene specific probes o... | https://en.wikipedia.org/wiki/Nuclear_run-on |
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as "The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards ". The IAEA defines nuclear secur... | https://en.wikipedia.org/wiki/Nuclear_safety_and_security |
Nuclear sexing is a technique for genetic sex determination in those species where XX chromosome pair is present. Nuclear sexing can be done by identifying Barr body , a drumstick like appendage located in the rim of the nucleus in somatic cells. Barr body is the inactive X chromosome which lies condensed in the nucleu... | https://en.wikipedia.org/wiki/Nuclear_sexing |
In nuclear physics , atomic physics , and nuclear chemistry , the nuclear shell model utilizes the Pauli exclusion principle to model the structure of atomic nuclei in terms of energy levels. [ 1 ] The first shell model was proposed by Dmitri Ivanenko (together with E. Gapon) in 1932. The model was developed in 1949 fo... | https://en.wikipedia.org/wiki/Nuclear_shell_model |
Nuclear spectroscopy is a superordinate concept of methods that uses properties of a nucleus to probe material properties . [ 1 ] [ 2 ] By emission or absorption of radiation from the nucleus information of the local structure is obtained, as an interaction of an atom with its closest neighbours. Or a radiation spectru... | https://en.wikipedia.org/wiki/Nuclear_spectroscopy |
Understanding the structure of the atomic nucleus is one of the central challenges in nuclear physics .
The cluster model describes the nucleus as a molecule-like collection of proton-neutron groups (e.g., alpha particles ) with one or more valence neutrons occupying molecular orbitals. [ 1 ] [ 2 ] [ 3 ] [ 4 ]
The li... | https://en.wikipedia.org/wiki/Nuclear_structure |
Nuclear transfer is a form of cloning . The step involves removing the DNA from an oocyte (unfertilised egg), and injecting the nucleus which contains the DNA to be cloned. In rare instances, the newly constructed cell will divide normally, replicating the new DNA while remaining in a pluripotent state. If the cloned... | https://en.wikipedia.org/wiki/Nuclear_transfer |
Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element. [ 1 ] Nuclear transmutation occurs in any process where the number of protons or neutrons in the nucleus of an atom is changed.
A transmutation can be achieved either by nuclear reactions (in which an outside p... | https://en.wikipedia.org/wiki/Nuclear_transmutation |
Nuclear transparency is the ratio of cross-sections for exclusive processes from the nuclei to those of the nucleons .
If a nuclear cross-section is denoted as σ N {\displaystyle \sigma _{N}} and free nucleon cross-section as σ 0 {\displaystyle \sigma _{0}} ,
then nuclear transparency can be defined as T = σ N / A σ 0... | https://en.wikipedia.org/wiki/Nuclear_transparency |
Nuclear transport refers to the mechanisms by which molecules move across the nuclear membrane of a cell. The entry and exit of large molecules from the cell nucleus is tightly controlled by the nuclear pore complexes (NPCs). Although small molecules can enter the nucleus without regulation, [ 1 ] macromolecules such a... | https://en.wikipedia.org/wiki/Nuclear_transport |
Nuclear winter is a severe and prolonged global climatic cooling effect that is hypothesized [ 1 ] [ 2 ] to occur after widespread firestorms following a large-scale nuclear war . [ 3 ] The hypothesis is based on the fact that such fires can inject soot into the stratosphere , where it can block some direct sunlight fr... | https://en.wikipedia.org/wiki/Nuclear_winter |
Nuclease protection assay is a laboratory technique used in biochemistry and genetics to identify individual RNA molecules in a heterogeneous RNA sample extracted from cells . The technique can identify one or more RNA molecules of known sequence even at low total concentration . The extracted RNA is first mixed with a... | https://en.wikipedia.org/wiki/Nuclease_protection_assay |
In fluid thermodynamics , nucleate boiling is a type of boiling that takes place when the surface temperature is hotter than the saturated fluid temperature by a certain amount but where the heat flux is below the critical heat flux . For water, as shown in the graph below, nucleate boiling occurs when the surface temp... | https://en.wikipedia.org/wiki/Nucleate_boiling |
In thermodynamics , nucleation is the first step in the formation of either a new thermodynamic phase or structure via self-assembly or self-organization within a substance or mixture . Nucleation is typically defined to be the process that determines how long an observer has to wait before the new phase or self-organi... | https://en.wikipedia.org/wiki/Nucleation |
Nucleation in microcellular plastic is an important stage which decides the final cell size, cell density and cell morphology of the foam. In the recent past, numerous researchers have studied the cell nucleation phenomenon in microcellular polymers.
Studies were performed with ultrasound induced nucleation during mic... | https://en.wikipedia.org/wiki/Nucleation_in_microcellular_foaming |
Nucleic acids are large biomolecules that are crucial in all cells and viruses. [ 1 ] They are composed of nucleotides , which are the monomer components: a 5-carbon sugar , a phosphate group and a nitrogenous base . The two main classes of nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). If th... | https://en.wikipedia.org/wiki/Nucleic_acid |
Nucleic acid analogues are compounds which are analogous (structurally similar) to naturally occurring RNA and DNA , used in medicine and in molecular biology research. Nucleic acids are chains of nucleotides, which are composed of three parts: a phosphate backbone, a pentose sugar, either ribose or deoxyribose , and o... | https://en.wikipedia.org/wiki/Nucleic_acid_analogue |
In molecular biology , the term double helix [ 1 ] refers to the structure formed by double-stranded molecules of nucleic acids such as DNA . The double helical structure of a nucleic acid complex arises as a consequence of its secondary structure , and is a fundamental component in determining its tertiary structure .... | https://en.wikipedia.org/wiki/Nucleic_acid_double_helix |
In molecular biology, hybridization (or hybridisation ) is a phenomenon in which single-stranded deoxyribonucleic acid ( DNA ) or ribonucleic acid ( RNA ) molecules anneal to complementary DNA or RNA . [ 1 ] Though a double-stranded DNA sequence is generally stable under physiological conditions, changing these conditi... | https://en.wikipedia.org/wiki/Nucleic_acid_hybridization |
Nucleic acid metabolism refers to the set of chemical reactions involved in the synthesis and degradation of nucleic acids ( DNA and RNA ). Nucleic acids are polymers (biopolymers) composed of monomers called nucleotides .
Nucleotide synthesis is an anabolic process that typically involves the chemical reaction of a p... | https://en.wikipedia.org/wiki/Nucleic_acid_metabolism |
Nucleic acid methods are the techniques used to study nucleic acids : DNA and RNA . | https://en.wikipedia.org/wiki/Nucleic_acid_methods |
In molecular biology , quantitation of nucleic acids is commonly performed to determine the average concentrations of DNA or RNA present in a mixture, as well as their purity. Reactions that use nucleic acids often require particular amounts and purity for optimum performance. To date, there are two main approaches use... | https://en.wikipedia.org/wiki/Nucleic_acid_quantitation |
Nucleic acid secondary structure is the basepairing interactions within a single nucleic acid polymer or between two polymers. It can be represented as a list of bases which are paired in a nucleic acid molecule. [ 1 ] The secondary structures of biological DNAs and RNAs tend to be different: biological DNA mostly exis... | https://en.wikipedia.org/wiki/Nucleic_acid_secondary_structure |
A nucleic acid sequence is a succession of bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the order of the nucleotides. By convention, sequences are usually presented from the 5' end t... | https://en.wikipedia.org/wiki/Nucleic_acid_sequence |
Experimental approaches of determining the structure of nucleic acids , such as RNA and DNA , can be largely classified into biophysical and biochemical methods. Biophysical methods use the fundamental physical properties of molecules for structure determination , including X-ray crystallography , NMR and cryo-EM . Bio... | https://en.wikipedia.org/wiki/Nucleic_acid_structure_determination |
Nucleic acid templated chemistry ( NATC ), or DNA-templated chemistry , is a tool used in the controlled synthesis of chemical compounds. The main advantage of NAT-chemistry (NATC) is that it allows the user to perform the chemical reaction as an intramolecular reaction . Two oligonucleotides . or their analogues, are ... | https://en.wikipedia.org/wiki/Nucleic_acid_templated_chemistry |
A nucleic acid test ( NAT ) is a technique used to detect a particular nucleic acid sequence and thus usually to detect and identify a particular species or subspecies of organism, often a virus or bacterium that acts as a pathogen in blood , tissue , urine , etc. NATs differ from other tests in that they detect geneti... | https://en.wikipedia.org/wiki/Nucleic_acid_test |
Nucleic acid thermodynamics is the study of how temperature affects the nucleic acid structure of double-stranded DNA (dsDNA). The melting temperature ( T m ) is defined as the temperature at which half of the DNA strands are in the random coil or single-stranded (ssDNA) state. T m depends on the length of the DNA mole... | https://en.wikipedia.org/wiki/Nucleic_acid_thermodynamics |
Nucleocosmochronology , or nuclear cosmochronology , is a technique used to determine timescales for astrophysical objects and events based on observed ratios of radioactive heavy elements and their decay products. It is similar in many respects to radiometric dating , in which trace radioactive impurities were selecti... | https://en.wikipedia.org/wiki/Nucleocosmochronology |
Nucleofection is an electroporation -based transfection method which enables transfer of nucleic acids such as DNA and RNA into cells by applying a specific voltage and reagents. Nucleofection, also referred to as nucleofector technology , was invented by the biotechnology company Amaxa. "Nucleofector" and "nucleofecti... | https://en.wikipedia.org/wiki/Nucleofection |
In chemistry , a nucleofuge (from nucleo- ' atomic nucleus ' and fuge ' to run away/escape ' ) is a leaving group which retains the lone pair of electrons from its previous bond with another species. For example, in the S N 2 mechanism , a nucleophile attacks an organic compound containing the nucleofuge (the bromo gro... | https://en.wikipedia.org/wiki/Nucleofuge |
A nucleogenic isotope , or nuclide , is one that is produced by a natural terrestrial nuclear reaction , other than a reaction beginning with cosmic rays (the latter nuclides by convention are called by the different term cosmogenic ). The nuclear reaction that produces nucleogenic nuclides is usually interaction with ... | https://en.wikipedia.org/wiki/Nucleogenic |
Nucleolus organizer regions (NORs) are chromosomal regions crucial for the formation of the nucleolus . In humans, the NORs are located on the short arms of the acrocentric chromosomes 13, 14, 15, 21 and 22, the genes RNR1 , RNR2 , RNR3 , RNR4 , and RNR5 respectively. [ 1 ] These regions code for 5.8S , 18S , and 28S r... | https://en.wikipedia.org/wiki/Nucleolus_organizer_region |
Nucleomodulins are a family of bacterial proteins that enter the nucleus of eukaryotic cells . [ 1 ]
This term comes from the contraction between "nucleus" and "modulins", which are microbial molecules that modulate the behaviour of eukaryotic cells. Nucleomodulins are produced by pathogenic or symbiotic bacteria. The... | https://en.wikipedia.org/wiki/Nucleomodulin |
Nucleomorphs are small, vestigial eukaryotic nuclei found between the inner and outer pairs of membranes in certain plastids . They are thought to be vestiges of red and green algal nuclei that were engulfed by a larger eukaryote. Because the nucleomorph lies between two sets of membranes, nucleomorphs support the endo... | https://en.wikipedia.org/wiki/Nucleomorph |
Nucleon pair breaking in fission has been an important topic in nuclear physics for decades. " Nucleon pair" refers to nucleon pairing effects which strongly influence the nuclear properties of a nuclide .
The most measured quantities in research on nuclear fission are the charge and mass fragments yields for uranium-... | https://en.wikipedia.org/wiki/Nucleon_pair_breaking_in_fission |
Nucleonica is a nuclear science web portal created by the European Commission's Joint Research Centre. [ 2 ] [ 3 ] which was later spun off to the company Nucleonica GmbH in March 2011. [ 1 ]
The company Nucleonica GmbH was founded by Dr. Joseph Magill in 2011 as a spin-off from the European Commission's Joint Researc... | https://en.wikipedia.org/wiki/Nucleonica |
In chemistry , a nucleophile is a chemical species that forms bonds by donating an electron pair . All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases .
Nucleophilic describes the affinity of a nucleophile to ... | https://en.wikipedia.org/wiki/Nucleophile |
Nucleophilic abstraction is a type of an organometallic reaction which can be defined as a nucleophilic attack on a ligand which causes part or all of the original ligand to be removed from the metal along with the nucleophile . [ 1 ] [ 2 ]
While nucleophilic abstraction of an alkyl group is relatively uncommon, there... | https://en.wikipedia.org/wiki/Nucleophilic_abstraction |
In organic chemistry , a nucleophilic addition ( A N ) reaction is an addition reaction where a chemical compound with an electrophilic double or triple bond reacts with a nucleophile , such that the double or triple bond is broken. Nucleophilic additions differ from electrophilic additions in that the former reactions... | https://en.wikipedia.org/wiki/Nucleophilic_addition |
A nucleophilic aromatic substitution ( S N Ar ) is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group , such as a halide , on an aromatic ring . Aromatic rings are usually nucleophilic, but some aromatic compounds do undergo nucleophilic substitution. Just as normally n... | https://en.wikipedia.org/wiki/Nucleophilic_aromatic_substitution |
A nucleoside-modified messenger RNA ( modRNA ) is a synthetic messenger RNA (mRNA) in which some nucleosides are replaced by other naturally modified nucleosides or by synthetic nucleoside analogues . [ 1 ] modRNA is used to induce the production of a desired protein in certain cells. An important application is the de... | https://en.wikipedia.org/wiki/Nucleoside-modified_messenger_RNA |
A nucleosome is the basic structural unit of DNA packaging in eukaryotes . The structure of a nucleosome consists of a segment of DNA wound around eight histone proteins [ 1 ] and resembles thread wrapped around a spool . The nucleosome is the fundamental subunit of chromatin . Each nucleosome is composed of a little l... | https://en.wikipedia.org/wiki/Nucleosome |
Nucleosome Remodeling Factor (NURF) is an ATP-dependent chromatin remodeling complex first discovered in Drosophila melanogaster (fruit fly) that catalyzes nucleosome sliding in order to regulate gene transcription . It contains an ISWI ATPase , making it part of the ISWI family of chromatin remodeling complexes. NURF ... | https://en.wikipedia.org/wiki/Nucleosome_remodeling_factor |
The nucleosome repeat length , ( NRL ) is the average distance between the centers of neighboring nucleosomes . NRL is an important physical chromatin property that determines its biological function. NRL can be determined genome-wide for the chromatin in a given cell type and state, or locally for a large enough genom... | https://en.wikipedia.org/wiki/Nucleosome_repeat_length |
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons (protons and neutrons) and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang , through nuclear reactions in a process called Big Bang nucleosynthesis . [ 1 ] After about 20 minutes... | https://en.wikipedia.org/wiki/Nucleosynthesis |
A nucleotidase is a hydrolytic enzyme that catalyzes the hydrolysis of a nucleotide into a nucleoside and a phosphate . [ 1 ]
For example, it converts adenosine monophosphate to adenosine , and guanosine monophosphate to guanosine .
Nucleotidases have an important function in digestion in that they break down consume... | https://en.wikipedia.org/wiki/Nucleotidase |
Nucleotides are organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate . They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in t... | https://en.wikipedia.org/wiki/Nucleotide |
Nucleotide diversity is a concept in molecular genetics which is used to measure the degree of polymorphism within a population. [ 1 ]
One commonly used measure of nucleotide diversity was first introduced by Nei and Li in 1979. This measure is defined as the average number of nucleotide differences per site between t... | https://en.wikipedia.org/wiki/Nucleotide_diversity |
Nucleotide pyrophosphatase/phosphodiesterase (NPP) is a class of dimeric enzymes that catalyze the hydrolysis of phosphate diester bonds. NPP belongs to the alkaline phosphatase (AP) superfamily of enzymes. [ 2 ] Humans express seven known NPP isoforms , [ 3 ] some of which prefer nucleotide substrates , some of which ... | https://en.wikipedia.org/wiki/Nucleotide_pyrophosphatase/phosphodiesterase |
Nucleotide sugars are the activated forms of monosaccharides . Nucleotide sugars act as glycosyl donors in glycosylation reactions. Those reactions are catalyzed by a group of enzymes called glycosyltransferases .
The anabolism of oligosaccharides - and, hence, the role of nucleotide sugars - was not clear until the 1... | https://en.wikipedia.org/wiki/Nucleotide_sugar |
In nucleotide sugar metabolism a group of biochemicals known as nucleotide sugars act as donors for sugar residues in the glycosylation reactions that produce polysaccharides . [ 1 ] They are substrates for glycosyltransferases . [ 2 ] The nucleotide sugars are also intermediates in nucleotide sugar interconversions th... | https://en.wikipedia.org/wiki/Nucleotide_sugars_metabolism |
The nucleotide universal IDentifier (nuID) in molecular biology, is designed to uniquely and globally identify oligonucleotide microarray probes.
Oligonucleotide probes of microarrays that are sequence identical may have different identifiers between manufacturers and even between different versions of the same compan... | https://en.wikipedia.org/wiki/Nucleotide_universal_IDentifier |
A nuclepore filter (brand name Nuclepore from Whatman, part of GE Healthcare) is a kind of filter in which holes a few micrometres in size have been created in a plastic (e.g. polycarbonate ) membrane . These filters are generally created by exposing the membrane to radiation that weakens the plastic and creates speci... | https://en.wikipedia.org/wiki/Nuclepore_filter |
In mathematics , and especially in order theory , a nucleus is a function F {\displaystyle F} on a meet-semilattice A {\displaystyle {\mathfrak {A}}} such that (for every p {\displaystyle p} in A {\displaystyle {\mathfrak {A}}} ): [ 1 ]
Every nucleus is evidently a monotone function.
Usually, the term nucleus is used... | https://en.wikipedia.org/wiki/Nucleus_(order_theory) |
Nuclides (or nucleides , from nucleus , also known as nuclear species) are a class of atoms characterized by their number of protons , Z , their number of neutrons , N , and their nuclear energy state . [ 1 ]
The word nuclide was coined by the American nuclear physicist Truman P. Kohman in 1947. [ 2 ] [ 3 ] Kohman def... | https://en.wikipedia.org/wiki/Nuclide |
The Nuffield Council on Bioethics is a UK-based independent charitable body, which examines and reports on bioethical issues raised by new advances in biological and medical research. Established in 1991, the Council is funded by the Nuffield Foundation , the Medical Research Council and the Wellcome Trust . [ 1 ] The ... | https://en.wikipedia.org/wiki/Nuffield_Council_on_Bioethics |
Nuisance wildlife management is the selective removal of problem individuals or populations of specific species of wildlife. Other terms for the field include wildlife damage management , wildlife control , and animal damage control . Some wild animal species may get used to human presence, causing property damage or r... | https://en.wikipedia.org/wiki/Nuisance_wildlife_management |
Nujol is a brand of light paraffin oil that was produced by Schering-Plough that was commonly used in infrared spectroscopy . As a paraffin oil it is largely chemically inert and has a relatively uncomplicated IR spectrum , with major peaks between 2950-2800, 1465-1450, and 1380–1300 cm −1 . [ 1 ] Nujol is primarily a ... | https://en.wikipedia.org/wiki/Nujol |
The Nuker Team was formed to use the Hubble Space Telescope , with its high-resolution imaging and spectroscopy, to investigate the central structure and dynamics of galaxies. The team used the HST to examine supermassive black holes and determined the relationship between a galaxy's central black hole's mass and velo... | https://en.wikipedia.org/wiki/Nuker_Team |
In mathematics , the word null (from German : null [ citation needed ] meaning "zero", which is from Latin : nullus meaning "none") is often associated with the concept of zero, or with the concept of nothing. [ 1 ] [ 2 ] It is used in varying contexts from "having zero members in a set " (e.g., null set) [ 3 ] to "hav... | https://en.wikipedia.org/wiki/Null_(mathematics) |
The null character is a control character with the value zero . [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] Many character sets include a code point for a null character – including Unicode ( Universal Coded Character Set ), ASCII ( ISO/IEC 646 ), Baudot , ITA2 codes, the C0 control code , and EBCDIC . In modern character sets, the ... | https://en.wikipedia.org/wiki/Null_character |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.