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16372100 | Fluorescence modulation in anion sensing by introducing intramolecular H-bonding interactions in host-guest adducts. | Fluorescence signaling in anion binding is modulated from quenching to enhancement by intramolecular H-bonding stabilization of anion-ionophore adducts; the intramolecular H-bonding is suggested to suppress the quenching processes otherwise possible and increase the conformational rigidity of the anionic adducts, leadi... |
16297497 | Dendrimer biocompatibility and toxicity. | The field of biomedical dendrimers is still in its infancy, but the explosion of interest in dendrimers and dendronised polymers as inherently active therapeutic agents, as vectors for targeted delivery of drugs, peptides and oligonucleotides, and as permeability enhancers able to promote oral and transdermal drug deli... |
16297481 | Sequences of avian reovirus M1, M2 and M3 genes and predicted structure/function of the encoded mu proteins. | We report the first sequence analysis of the entire complement of M-class genome segments of an avian reovirus (ARV). We analyzed the M1, M2 and M3 genome segment sequences, and sequences of the corresponding muA, muB and muNS proteins, of two virus strains, ARV138 and ARV176. The ARV M1 genes were 2,283 nucleotides in... |
16327890 | De novo design of a stable N-terminal helical foldamer. | A peptide NTH-18 was synthesized in which a N-terminal helix is stabilised by two crossed disulfide bonds to a C-terminal extension. The design was inspired by the structure of the neurotoxic peptide apamin, which has previously been used to stabilise helices in miniature enzymes. CD- and NMR-spectroscopy indicated tha... |
16292590 | The mGluR5 antagonist MPEP selectively inhibits the onset and maintenance of ethanol self-administration in C57BL/6J mice. | <h4>Rationale</h4>Many of the biochemical, physiological, and behavioral effects of ethanol are known to be mediated by ionotropic glutamate receptors. Emerging evidence implicates metabotropic glutamate receptors (mGluRs) in the biobehavioral effects of ethanol and other drugs of abuse, but there is little information... |
16292588 | Bioresorbable polymers: heading for a new generation of spinal cages. | The use of polymer-based bioresorbable materials is now expanding to the realm of spinal interbody fusion. Bioresorbable polymers have important advantages over metals, because they are temporary, much less stiff, and radiolucent. Most promising is a group of alpha-polyesters, in particular polylactide acids (PLAs). Th... |
16287940 | Mean curvature as a major determinant of beta-sheet propensity. | <h4>Motivation</h4>Despite the importance of beta-sheets as building blocks in proteins and also toxic elements in the pathological disorders, ranging from Alzheimer's disease to mad cow disease, the principles underlying their stability are not well understood. Non-random beta-sheet propensities of amino acids have be... |
16279839 | Systematic discovery of new recognition peptides mediating protein interaction networks. | Many aspects of cell signalling, trafficking, and targeting are governed by interactions between globular protein domains and short peptide segments. These domains often bind multiple peptides that share a common sequence pattern, or "linear motif" (e.g., SH3 binding to PxxP). Many domains are known, though comparative... |
16158306 | Antitumor activity of novel N-sulfonylpyrimidine derivatives on the growth of anaplastic mammary carcinoma in vivo. | <h4>Purpose</h4>The purpose of this study was to investigate in vivo antitumor activity of newly synthesized N-sulfonylpyrimidine derivatives 1-(p-toluenesulfonyl)cytosine (4H), 1-(p-toluenesulfonyl)cytosine hydrochloride (4HxHCl) and zinc(II) complex of 1-(p-toluenesulfonyl)cytosine (4K).<h4>Materials and methods</h4>... |
16505905 | Host-guest complexation of a fluorescent and electrochemical chemsensor for fluoride anion. | Host-guest complexation of a ferrocenenylphalene dyad 1, 1,1'-diaceylferrocenyl-3-hydroxyl-2-naphthoylhydrazone, as a fluorescent and electrochemical chemosensor for fluoride anion, was investigated. Crystal structure analysis revealed that the two naphthyl arms of compound 1 positioned in the same side about the ferro... |
16317456 | Solvent-induced supramolecular isomerism in [Pt(S=C(NH2)2)4]2+ croconate salts. | The role of solvent (and other species) in the formation of networks from tetrakis(thiourea)platinum(II) cations and croconate anions is examined, with crystallisations from DMSO giving rise to a structure containing solvent filled channels. |
16290254 | Targeted drug delivery with dendrimers: comparison of the release kinetics of covalently conjugated drug and non-covalent drug inclusion complex. | Dendrimers have unique characteristics including monodispersity and modifiable surface functionality, along with highly defined size and structure. This makes these polymers attractive candidates as carriers in drug delivery applications. Drug delivery can be achieved by coupling a drug to polymer through one of two ap... |
16286507 | Evolution of skeletal type e-c coupling: a novel means of controlling calcium delivery. | The functional separation between skeletal and cardiac muscles, which occurs at the threshold between vertebrates and invertebrates, involves the evolution of separate contractile and control proteins for the two types of striated muscles, as well as separate mechanisms of contractile activation. The functional link be... |
16270218 | Kinetochore fiber formation in animal somatic cells: dueling mechanisms come to a draw. | The attachment to and movement of a chromosome on the mitotic spindle are mediated by the formation of a bundle of microtubules (MTs) that tethers the kinetochore on the chromosome to a spindle pole. The origin of these "kinetochore fibers" (K fibers) has been investigated for over 125 years. As noted in 1944 by Schrad... |
16437170 | A dinuclear triple-stranded helicate with a bis(benzene-o-dithiolato) ligand. | The bis(benzene-o-dithiol) ligand H4-1 reacts with Ti4+ in a self-assembly reaction to give the dinuclear triple-stranded helicate [Ti2(1)3]4- which is the first helicate build exclusively from benzene-o-dithiolato donor groups. |
16395437 | Single- and multi-photon excited fluorescence from serotonin complexed with beta-cyclodextrin. | The fluorescence of serotonin on binding with beta-cyclodextrin has been studied using both steady state and time-resolved methods. Steady state fluorescence intensity of serotonin at 340 nm showed approximately 30% increase in intensity on binding with K(A) approximately 60 dm(3) mol(-1) and the fluorescence lifetimes... |
16330848 | Four nitrobenzaldehyde isonicotinoylhydrazones at 120 K: four different supramolecular structures in two and three dimensions. | The molecules of 2-nitrobenzaldehyde isonicotinoylhydrazone, C13H10N4O3, (I), are linked into a three-dimensional framework by a combination of one N-H...N and three C-H...O hydrogen bonds. In the isomeric compound 3-nitrobenzaldehyde isonicotinoylhydrazone, (II), the molecules are linked into complex sheets by a combi... |
16330845 | Methyl 4-O-beta-D-galactopyranosyl alpha-D-glucopyranoside (methyl alpha-lactoside). | Methyl alpha-lactoside, C13H24O11, (I), is described by glycosidic torsion angles varphi (O5gal-C1gal-O1gal-C4glc) and psi (C1gal-O1gal-C4glc-C5glc), which have values of -93.52 (13) and -144.83 (11) degrees, respectively, where the ring atom numbering conforms to the convention in which C1 is the anomeric C atom and C... |
16289434 | Characterization of dendrimers. | Dendrimers pertain both to the molecular chemistry world for their step by step controlled syntheses, and to the polymer world because of their repetitive structure made of monomers; thus they benefit from analytical techniques from both worlds. This review is a survey of the main analytical techniques used for the cha... |
16289433 | Transepithelial and endothelial transport of poly (amidoamine) dendrimers. | This article summarizes our efforts to evaluate the potential of poly (amidoamine) (PAMAM) dendrimers as carriers for oral drug delivery. Specifically, the permeability of a series of cationic PAMAM-NH2 (G0-G4) dendrimers across Caco-2 cell monolayers was evaluated as a function of dendrimer generation, concentration, ... |
16289104 | In vitro selection of DNA aptamers binding ethanolamine. | We have identified aptamers (synthetic oligonucleotides) binding to the very small molecule ethanolamine with high affinity down to the low nanomolar range. These aptamers were selected for their ability to bind to ethanolamine immobilised on magnetic beads, from an 96mer library of initially about 1 x 10(16) randomise... |
16287814 | Theoretical study of the Hoogsteen-Watson-Crick junctions in DNA. | A series of d (AT)(n) oligonucleotides containing mixtures of normal B-type Watson-Crick and antiparallel Hoogsteen helices have been studied using molecular dynamics simulation techniques to analyze the structural and thermodynamic impact of the junction between Watson-Crick and antiparallel Hoogsteen structures. Anal... |
16286368 | In vitro selection, characterization, and application of deoxyribozymes that cleave RNA. | Over the last decade, many catalytically active DNA molecules (deoxyribozymes; DNA enzymes) have been identified by in vitro selection from random-sequence DNA pools. This article focuses on deoxyribozymes that cleave RNA substrates. The first DNA enzyme was reported in 1994 and cleaves an RNA linkage. Since that time,... |
16284269 | Calculation of absolute protein-ligand binding affinity using path and endpoint approaches. | A comparative analysis is provided of rigorous and approximate methods for calculating absolute binding affinities of two protein-ligand complexes: the FKBP protein bound with small molecules 4-hydroxy-2-butanone and FK506. Our rigorous approach is an umbrella sampling technique where a potential of mean force is deter... |
16284264 | Chemical and structural disorder in eumelanins: a possible explanation for broadband absorbance. | We report the results of an experimental and theoretical study of the electronic and structural properties of a key eumelanin precursor-5,6,-dihydroxyindole-2-carboxylic acid (DHICA)-and its dimeric forms. We have used optical spectroscopy to follow the oxidative polymerization of DHICA to eumelanin and observe red shi... |
16284250 | A structural model for unfolded proteins from residual dipolar couplings and small-angle x-ray scattering. | Natively unfolded proteins play key roles in normal and pathological biochemical processes. Despite their importance for function, this category of proteins remains beyond the reach of classical structural biology because of their inherent conformational heterogeneity. We present a description of the intrinsic conforma... |
16482291 | Computational study of a chiral supramolecular arrangement of organic structure directing molecules for the AFI structure. | Molecular mechanics computational methods have been employed to study the structure directing effect of S-(-)-1-benzyl-2-pyrrolidiniummethanol molecules towards microporous aluminophosphate materials with the AFI structure. These chiral molecules form dimers inside the one-dimensional AFI channel, which are the active ... |
16290152 | Nano-sized MRI contrast agents with dendrimer cores. | Gadolinium-based MRI contrast agents (CAs) can be effective at a approximately 100-fold lower concentration of Gadolinium ions in comparison to the concentration of Iodine atoms required for CT imaging. Therefore, a number of dendrimer based macromolecular MRI CAs of various sizes and properties prepared employing rela... |
16289820 | Conversion of A3 adenosine receptor agonists into selective antagonists by modification of the 5'-ribofuran-uronamide moiety. | The highly selective agonists of the A(3) adenosine receptor (AR), Cl-IB-MECA (2-chloro-N(6)-(3-iodobenzyl)-5'-N-methylcarboxamidoadenosine), and its 4'-thio analogue, were successfully converted into selective antagonists simply by appending a second N-methyl group on the 5'-uronamide position. The 2-chloro-5'-(N,N-di... |
16289242 | Simultaneous removal of organic compounds and heavy metals from soils by electrokinetic remediation with a modified cyclodextrin. | Thousands of sites are contaminated with both heavy metals and organic compounds and these sites pose a major threat to public health and the environment. Previous studies have shown that electrokinetic remediation has potential to remove heavy metals and organic compounds when they exist individually in low permeabili... |
16282585 | Role of stacking interactions in the binding sequence preferences of DNA bis-intercalators: insight from thermodynamic integration free energy simulations. | The major structural determinant of the preference to bind to CpG binding sites on DNA exhibited by the natural quinoxaline bis-intercalators echinomycin and triostin A, or the quinoline echinomycin derivative, 2QN, is the 2-amino group of guanine (G). However, relocation of this group by means of introduction into the... |
16282375 | Molecular mechanisms of Sonic hedgehog mutant effects in holoprosencephaly. | Holoprosencephaly (HPE), a human developmental brain defect, usually is also associated with varying degrees of midline facial dysmorphism. Heterozygous mutations in the Sonic hedgehog (SHH) gene are the most common genetic lesions associated with HPE, and loss of Shh function in the mouse produces cyclopia and alobar ... |
16307724 | Functionalized carbon nanotubes as emerging nanovectors for the delivery of therapeutics. | Functionalized carbon nanotubes (f-CNT) are emerging as a new family of nanovectors for the delivery of different types of therapeutic molecules. The application of CNT in the field of carrier-mediated delivery has become possible after the recent discovery of their capacity to penetrate into the cells. CNT can be load... |
16303133 | Determinants of product topology in a hybrid Cre-Tn3 resolvase site-specific recombination system. | Many natural DNA site-specific recombination systems achieve directionality and/or selectivity by making recombinants with a specific DNA topology. This property requires that the DNA architecture of the synapse and the mechanism of strand exchange are both under strict control. Previously we reported that Tn3 resolvas... |
16283383 | Hsp90 inhibitors cause G2/M arrest associated with the reduction of Cdc25C and Cdc2 in lung cancer cell lines. | <h4>Purpose</h4>Hsp90, a molecular chaperone, is involved in folding, assembly, maturation, and stabilization of the client proteins which regulate survival of cancer cells, and thus Hsp90 inhibitors may be potential molecular targeting agents for cancer treatment. We investigated whether Hsp90 inhibitors have therapeu... |
16280623 | Elastic network models for understanding biomolecular machinery: from enzymes to supramolecular assemblies. | With advances in structure genomics, it is now recognized that knowledge of structure alone is insufficient to understand and control the mechanisms of biomolecular function. Additional information in the form of dynamics is needed. As demonstrated in a large number of studies, the machinery of proteins and their compl... |
16462955 | Exchange coupling across the cyanide bridge: structural and DFT interpretation of the magnetic properties of a binuclear chromium(III) complex. | The reaction of [Cr(CN)6]3- with a mixture of trans-[Cr(cyclam)(OH)2]Cl, [Cr(cyclam)(OH)Cl]Cl and [Cr(cyclam)Cl2]Cl affords the cyanide bridged dimer, trans-[HO-Cr(cyclam)-NC-Cr(CN)5]-. The tetraphenylphosphonium salt of the anion crystallizes in space group P2(1)/n and shows a bent arrangement of the Cr1-CN-Cr2 unit w... |
16333501 | Hierarchical supramolecular fullerene architectures with controlled dimensionality. | Self-assembly of a fullerene derivative with long alkyl chains in different solvents results in the formation of hierarchically-ordered supramolecular assemblies with well-defined 1, 2 and 3D architectures such as vesicles, fibers, discs and cones, whose fundamental structural sub-unit consists of bilayers. |
16288896 | The fabrication of hollow spherical copper sulfide nanoparticle assemblies with 2-hydroxypropyl-beta-cyclodextrin as a template under sonication. | 2-Hydroxypropyl-beta-cyclodextrin was used as a template to fabricate hollow spherical copper sulfide nanoparticle assemblies in the presence of sonication. The as-prepared spheres were uniform in shape and have well-defined shells composed of one-layered CuS nanoparticles. The interaction between the Cu ions and HP-be... |
16283291 | Probing the importance of lateral hydrophobic association in self-assembling peptide hydrogelators. | A class of peptides has been designed whose ability to self-assemble into hydrogel is dependent on their conformationally folded state. Under unfolding conditions aqueous peptide solutions are freely flowing having the viscosity of water. When folding is triggered by external stimuli, peptides adopt a beta-hairpin conf... |
16280167 | Display and selection of chicken IgA Fab fragments. | Passive immune therapy is regaining interest to prevent and cure infectious diseases both in human and veterinary medicine. Therefore, systems are required that enable efficient targeted selection of antibodies originating from virtually any animal species. Here, a system for the selection of chicken IgA, using phage d... |
16280122 | CysLT1 leukotriene receptor antagonists inhibit the effects of nucleotides acting at P2Y receptors. | Montelukast and pranlukast are orally active leukotriene receptor antagonists selective for the CysLT1 receptor. Conversely, the hP2Y(1,2,4,6,11,12,13,14) receptors represent a large family of GPCRs responding to either adenine or uracil nucleotides, or to sugar-nucleotides. Montelukast and pranlukast were found to inh... |
16278031 | Regiochemical functionalization of a nanoscale cage-like structure: robust core-shell nanostructures crafted as vessels for selective uptake and release of small and large guests. | As synthetic methods evolve toward the preparation of increasingly complex nanostructured materials inspired from biological nano-objects, the ability to tailor the three-dimensional architecture and the placement of functional groups at well-defined positions within those frameworks is advancing. In this report, we de... |
16277654 | Complement receptor 1 polymorphisms associated with resistance to severe malaria in Kenya. | <h4>Background</h4>It has been hypothesized that the African alleles Sl2 and McCb of the Swain-Langley (Sl) and McCoy (McC) blood group antigens of the complement receptor 1 (CR1) may confer a survival advantage in the setting of Plasmodium falciparum malaria, but this has not been demonstrated.<h4>Methods</h4>To test ... |
16365639 | Differential receptor arrays and assays for solution-based molecular recognition. | Nature has inspired an emergent supramolecular field of synthetic receptor arrays and assays for the pattern-based recognition of various bioanalytes and metal species. The synthetic receptors are not necessarily selective for a particular analyte, but the combined signal response from the array is diagnostic for the a... |
16357966 | Controlled formation and topologies of thiophenolate-based macrocycles: rings, cylinders and bowls. | The Schiff-base condensations of 1,3-diaminopropane with a protected thiophenol dialdehyde in the presence of Ni(2+), Pd(2+) or Zn(2+) can be controlled to yield either mononuclear acyclic, or 2 + 2 and 4 + 4 macrocyclic complexes by the choice of both metal cation and counteranion. The Ni(2+) complex of the 2 + 2 macr... |
16333514 | 45- and 70-base DNA supramolecular polymerizations on quartz crystal microbalance biosensor. | Supramolecular polymerizations of 45- and 70- base DNAs on the surface of an in-situ time-resolved 27 MHz quartz crystal microbalance biosensor. |
16327898 | A novel bis-phenanthridine triamine with pH controlled binding to nucleotides and nucleic acids. | The new bis-phenanthridine triamine is characterised by three pK(a) values: 3.65; 6.0 and >7.5. A significant difference in the protonation state of at pH = 5 (four positive charges) and at pH = 7 (less than two positive charges) accounts for the strong dependence of -nucleotide binding constants on nucleotide charge u... |
16275922 | Cyclin H binding to the RARalpha activation function (AF)-2 domain directs phosphorylation of the AF-1 domain by cyclin-dependent kinase 7. | The transcriptional activity of nuclear retinoic acid receptors (RARs), which act as RAR/retinoid X receptor (RXR) heterodimers, depends on two activation functions, AF-1 and AF-2, which are targets for phosphorylations and synergize for the activation of retinoic acid target genes. The N-terminal AF-1 domain of RARalp... |
16273097 | Newly generated T cell receptor microclusters initiate and sustain T cell activation by recruitment of Zap70 and SLP-76. | T cell receptor (TCR) activation and signaling precede immunological synapse formation and are sustained for hours after initiation. However, the precise physical sites of the initial and sustained TCR signaling are not definitively known. We report here that T cell activation was initiated and sustained in TCR-contain... |
16307142 | Multivalent, bifunctional dendrimers prepared by click chemistry. | Unsymmetrical dendrimers, containing both mannose binding units and coumarin fluorescent units, have been prepared using click chemistry and shown to be highly efficient, dual-purpose recognition/detection agents for the inhibition of hemagglutination. |
16276403 | Elucidation of clathrin-mediated endocytosis in tetrahymena reveals an evolutionarily convergent recruitment of dynamin. | Ciliates, although single-celled organisms, contain numerous subcellular structures and pathways usually associated with metazoans. How this cell biological complexity relates to the evolution of molecular elements is unclear, because features in these cells have been defined mainly at the morphological level. Among th... |
16275158 | Study of inclusion complex formation between tropaeolin OO and beta-cyclodextrin by spectrophotometry and Infrared spectroscopy. | The mechanism of the inclusion of tropaeolin OO (TPOO) and beta-cyclodextrin (beta-CD) has been studied by spectrophotometry. The inclusion depth of the guest molecule in the host molecule was demonstrated by infrared spectrometry. Effect of the pH, concentrations of beta-CD, solvents and ionic strength on the inclusio... |
16272447 | Cholesterol depletion induces solid-like regions in the plasma membrane. | Glycosylphosphatidylinositol-linked and transmembrane major histocompatibility complex (MHC) class II I-E(k) proteins, as well as N-(6-tetramethylrhodaminethiocarbamoyl)-1,2-dihexadecanoyl-sn-glycero-3-phosphoethanolamine (Tritc-DHPE), are used as probes to determine the effect of cholesterol concentration on the organ... |
16272445 | Conversion of a porin-like peptide channel into a gramicidin-like channel by glycine to D-alanine substitutions. | The beta-barrel and beta-helix formation, as in porins and gramicidin, respectively, represent two distinct mechanisms for ion channel formation by beta-sheet proteins in membranes. The design of beta-barrel proteins is difficult due to incomplete understanding of the basic principles of folding. The design of gramicid... |
16272442 | Antagonist-induced deadhesion of specifically adhered vesicles. | By use of a model system consisting of giant vesicles adhering to flat substrates, we identified, both experimentally and theoretically, two new control mechanisms for antagonist-induced deadhesion. Adhesion is established by specific binding of surface-grafted E-selectin and vesicle-carrying oligosaccharide Lewis(X). ... |
16272436 | Optical microscopy of growing insulin amyloid spherulites on surfaces in vitro. | Amyloid fibrils are often found arranged into large ordered spheroid structures, known as spherulites, occurring in vivo and in vitro. The spherulites are predominantly composed of radially ordered amyloid fibrils, which self-assemble from protein in solution. We have observed and measured amyloid spherulites forming f... |
16272434 | Formation kinetics of insulin-based amyloid gels and the effect of added metalloporphyrins. | The kinetics of insulin-based amyloid gel formation has been studied using extinction and fluorescence detection. The process is treated as autocatalytic, and the kinetic profiles are fit using a nonconventional analysis involving a time-dependent rate constant (factor): k(t) = k(o) + k(c)(k(c)t)(n). The dependence of ... |
16272417 | Fixation of the human-specific CMP-N-acetylneuraminic acid hydroxylase pseudogene and implications of haplotype diversity for human evolution. | The human CMP-N-acetylneuraminic acid hydroxylase gene (CMAH) suffered deletion of an exon that encodes an active center for the enzyme approximately 3.2 million years ago (MYA). We analyzed a 7.3-kb intronic region of 132 CMAH genes to explore the fixation process of this pseudogene and the demographic implication of ... |
16272155 | Mdv1 interacts with assembled dnm1 to promote mitochondrial division. | The dynamin-related GTPase, Dnm1, self-assembles into punctate structures that are targeted to the outer mitochondrial membrane where they mediate mitochondrial division. Post-targeting, Dnm1-dependent division is controlled by the actions of the WD repeat protein, Mdv1, and the mitochondrial tetratricopeptide repeat-l... |
16271768 | cDNA cloning and phylogenetic analysis of the sixth complement component in rainbow trout. | The sixth complement protein (C6) is an essential component of the membrane attack complex (MAC); the end product of the lytic pathway of complement activation. The MAC complex constitutes a supramolecular assembly containing the five precursor proteins C5b, C6, C7, C8, and C9. Once assembled on the target surface it f... |
16402150 | [Ln(terpy)]3+ (Ln = Sm, Gd) entity forms isolated magnetic chains with [W(CN)8]3-. | The reaction between Ln(NO3)3*xH2O, Cs3[W(V)(CN)8]*H2O and 2,2':6',2''-terpyridine (terpy) leads to the original isomorphous cyano-bridged [Ln(III)(terpy)(DMF)4][W(V)(CN)8] *6H2O [Ln = Gd (1), Sm (2)] 1-D chains. The crystal structures of {Ln(III)W(V)} chains and consist of alternating {[W(CN)8]} and {[Ln(terpy)]} buil... |
16277754 | Large-scale approaches for glycobiology. | Glycosylation, the attachment of carbohydrates to proteins and lipids, influences many biological processes. Despite detailed characterization of the cellular components that carry out glycosylation, a complete picture of a cell's glycoconjugates remains elusive because of the challenges inherent in characterizing comp... |
16437179 | Coordination frameworks constructed from bipyridyl piperazine and MCl2 (M = Co, Ni, Zn): structural characterization and optical properties. | Three metal-organic polymers, [CoCl2(bpfp)]n 1, {[NiCl2(bpfp)2](H2O)3}n 2 and [ZnCl2(bpfp)]n 3 (bpfp = N,N'-bis(3-pyridylformyl)piperazine), are formed by the self-assembly of the flexible bpfp with MCl2 (M = Co, Ni, Zn), respectively. X-Ray single-crystal structural analysis reveals that polymer 1 exhibits a novel gri... |
16290901 | Protein interactions and misfolding analyzed by AFM force spectroscopy. | Protein misfolding is conformational transition dramatically facilitating the assembly of protein molecules into aggregates of various morphologies. Spontaneous formation of specific aggregates, mostly amyloid fibrils, was initially believed to be limited to proteins involved in the development of amyloidoses. However,... |
16294258 | Synthesis of nitrogen and sulfur macrocycles with cis exogenous oxygen and sulfur donor atoms. | A series of new N4 and N8 macrocycles has been prepared, that includes cis-exogenous O2, S2 and S/O atoms to allow chelation to a metal external to the macrocyclic ring. We found that thioamide units within the macrocycles were unstable to attack by secondary amines and thus alkylated precursors containing only tertiar... |
16267273 | Conserved prefusion protein assembly in regulated exocytosis. | The regulated release of hormones and neurotransmitters is a fundamental process throughout the animal kingdom. The short time scale for the calcium triggering of vesicle fusion in regulated secretion suggests that the calcium sensor synaptotagmin and the soluble N-ethylmaleimide-sensitive factor attachment protein rec... |
16267129 | Computational docking and solution x-ray scattering predict a membrane-interacting role for the histone domain of the Ras activator son of sevenless. | The Ras-specific nucleotide exchange factor son of sevenless (SOS) is a large, multidomain protein with complex regulation, including a Ras-dependent allosteric mechanism. The N-terminal segment of SOS, the histone domain, contains two histone folds, which is highly unusual for a cytoplasmic protein. Using a combinatio... |
16267051 | Cholesterol-mediated neurite outgrowth is differently regulated between cortical and hippocampal neurons. | The acquisition of neuronal type-specific morphogenesis is a central feature of neuronal differentiation and has important consequences for region-specific nervous system functions. Here, we report that the cell type-specific cholesterol profile determines the differential modulation of axon and dendrite outgrowths in ... |
16266811 | A dynamic view of the immunological synapse. | T cell activation requires interactions of T cell antigen receptors (TCR) and peptides presented by major histocompatibility complex molecules (MHCp) in an adhesive junction between the T cell and antigen-presenting cell. Stable junctions with bull's eye supramolecular activation clusters (SMACs) have been defined as i... |
16266807 | Synthesis of hypermodified adenosine derivatives as selective adenosine A3 receptor ligands. | We investigated the A(3)AR affinity and selectivity of a series of 2-substituted 3'-azido and 3'-amino adenosine derivatives as well as some 5'-uronamide derivatives thereof. All compounds showed high A(3)AR selectivity. While the 3'-azides appeared to be A(3)AR antagonists with moderate A(3)AR affinity, their 3'-amino... |
16266727 | Sublingual administration of Delta9-tetrahydrocannabinol/beta-cyclodextrin complex increases the bioavailability of Delta9-tetrahydrocannabinol in rabbits. | The bioavailability of Delta(9)-tetrahydrocannabinol (THC) was determined after its sublingual administration as solid THC/beta-cyclodextrin (THC/beta-CD) complex, and was compared to oral administration of ethanolic THC, in rabbits. The absolute bioavailability of THC after sublingual administration of solid THC/beta-... |
16266723 | Partial agonistic effect of 9-hydroxycorynantheidine on mu-opioid receptor in the guinea-pig ileum. | Mitragynine is an indole alkaloid isolated from the Thai medicinal plant Mitragyna speciosa that is reported to have opioid agonistic properties. The 9-demethyl analogue of mitragynine, 9-hydroxycorynantheidine, is synthesized from mitragynine. 9-Hydroxycorynantheidine inhibited electrically stimulated guinea-pig ileum... |
16266713 | Unusual resolution of N-(3,5-dinitrobenzoyl)-alpha-amino acids on a chiral stationary phase based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. | While HPLC chiral stationary phases (CSPs) based on chiral crown ethers have been known useful for the resolution of only racemic primary amino compounds or some secondary amino compounds, in this study, we first demonstrated that the CSP based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid is also useful for the r... |
16263308 | Close encounters of the first and second kind: T-DC and T-B interactions in the lymph node. | Cellular interactions in lymphoid organs initiate the immune response and determine its outcome. Using two-photon microscopy in the lymph node, several groups have begun to investigate the motility characteristics and interactions among T lymphocytes, B lymphocytes, and dendritic cells (DC) in lymphoid organs. In the f... |
16263160 | Modifying oocytes and embryos to improve their cryopreservation. | Numerous studies indicate that in vitro-produced bovine embryos do not survive cryopreservation as well as those produced in vivo. Furthermore, embryos cultured in vitro in the absence of blood serum are more cryotolerant than embryos cultured in media containing serum. Although in vivo-produced embryos are more cryoto... |
16260174 | Dendrimers as artificial enzymes. | Dendrimers are regular tree-like macromolecules accessible by chemical synthesis from a variety of building blocks. Their topology enforces a globular shape that offers a unique opportunity to design artificial enzymes. Catalytic groups such as metal complexes and cofactors can be placed at the dendrimer core to exploi... |
16260064 | Optimization, evaluation, and characterization of molecularly imprinted polymers. | The underlying mechanisms for molecular recognition exhibited by the imprinting effect can be attributed to two processes. The pre-organization of complementary functional groups in the polymer by the template and the formation of a shape-selective cavity that is complementary to the template. However, measurements of ... |
32646113 | Surfactant aggregates hosting a photoresponsive amphiphile: structure and photoinduced conformational changes. | This paper reports the aggregational and photoresponsive properties of aqueous solutions of a cationic bolaform surfactant, where an azobenzene moiety connects two identical hydrophobic chains terminated by quaternary ammonium groups. In analogy to common surfactants, the cationic bolaform molecules form supramolecular... |
32646112 | Coarse-grained simulation studies of a liquid crystal dendrimer: towards computational predictions of nanoscale structure through microphase separation. | Coarse-grained simulations are described in which the behaviour of a system of model liquid crystalline dendrimer molecules is studied in both liquid and smectic-A liquid crystalline phases. The model system is based on a third generation carbosilane dendrimer, which is functionalised at the surface by short polymeric ... |
26631654 | A Theoretical Investigation of the Geometries and Binding Energies of Molecular Tweezer and Clip Host-Guest Systems. | A quantum chemical study of host-guest systems with dimethylene-bridged clips and tetramethylene-bridged tweezers as host molecules and six different aliphatic and aromatic substrates as guests is presented. The geometries and binding energies of the complexes are investigated using the recently developed density funct... |
19865587 | Nanoparticle Formulation Increases Oral Bioavailability of Poorly Soluble Drugs: Approaches Experimental Evidences and Theory. | The increasing frequency at which poorly soluble new chemical entities are being discovered raises concerns in the pharmaceutical industry about drugability associated with erratic dissolution and low bioavailability of these hydrophobic compounds. Nanonization provides a plausible pharmaceutical basis for enhancing or... |
19865495 | Global Governmental Investment in Nanotechnologies. | Nanotechnologies seem to have huge potential to bring benefits in areas as diverse as drug development, water decontamination, information and communication infrastructures, and the production of stronger, lighter and perfect nanomaterials. This potential attracts global investment from governments and private sectors ... |
16853858 | Two-photon absorption properties of self-assemblies of butadiyne-linked bis(imidazolylporphyrin). | Supramolecular porphyrin self-assemblies have been prepared from butadiyne-linked bis(imidazolylporphyrin) by complementary coordination of imidazole to zinc, and their two-photon absorption (2PA) and higher-order nonlinear absorption properties were investigated over femtosecond time scales using an open-aperture Z-sc... |
16853832 | Electrochemical characterization of polyelectrolyte/gold nanoparticle multilayers self-assembled on gold electrodes. | Polyelectrolyte/gold nanoparticle multilayers composed of poly(l-lysine) (pLys) and mercaptosuccinic acid (MSA) stabilized gold nanoparticles (Au NPs) were built up using the electrostatic layer-by-layer self-assembly technique upon a gold electrode modified with a first layer of MSA. The assemblies were characterized ... |
16853814 | Self-assembled multibilayers of europium alkanoates: structure, photophysics, and mesomorphic behavior. | A series of europium alkanoates (C(n-1)H(2n-1)CO(2))(3)Eu, (n = 14, 16, 18, 20) have been synthesized and characterized in detail. X-ray diffraction and Fourier transform infrared spectroscopic measurements confirm the multibilayer structure of these homologues. In such bilayers, the europium ionic layers are well sepa... |
16853809 | Recoverable solution reaction of HiPco carbon nanotubes with hydrogen peroxide. | There is increasing interest in developing single-walled carbon nanotubes (SWNTs)-based optical biosensors for remote or in vitro and in vivo sensing because the near-IR optical properties of SWNTs are very sensitive to surrounding environmental changes. Many enzyme-catalyzed reactions yield hydrogen peroxide (H(2)O(2)... |
16853796 | Characterization of heterogeneously functionalized dendrimers by mass spectrometry and EPR spectroscopy. | Starburst dendrimers are receiving considerable attention as templates for the assembly of structured arrays of molecular components. This research motivates the development of improved methods for dendrimer characterization-specifically, for determining the numbers, distributions of numbers, and spatial distribution o... |
16853784 | Proper gaussian basis sets for density functional studies of water dimers and trimers. | The accuracy of the Perdew-Burke-Ernzerhof and Tao-Perdew-Staroverov-Scuseria density functionals for describing noncovalent interaction energies in small water clusters is studied by testing 11 basis sets on a reduced test set proposed by Dahlke and Truhlar (J. Phys. Chem. B 2005, 109, 15677). We have also tested vari... |
16853594 | Entrapment of organic solutes by the water cage in the nanochannel of MCM-41. | The effect of MCM-41 on the ESR spectrum of an aqueous spin probe solution was observed. The sharp ESR spectrum turns into a rather broad characteristic one leaving a sharper signal as the minor component, immediately after the addition of MCM-41 powder to the system. This observation indicates that MCM-41 traps the so... |
16833286 | Enhancement of the large stokes-shifted fluorescence emission from the 2-(2'-hydroxyphenyl)benzoxazole core in a dendrimer. | The photochemical properties of a series of newly synthesized dendrimers, 4-6, having a 2-(2'-hydroxyphenyl)benzoxazole (HBO) core, were studied in benzene. The fluorescence quantum yields (Phi(f)) were determined to be 0.022, 0.030, and 0.038 for 4, 5, and 6, respectively, increasing in higher generation dendrimers. W... |
16834304 | Nonplanar heme deformations and excited state displacements in nickel porphyrins detected by Raman spectroscopy at soret excitation. | We have correlated the Raman intensities of out-of-plane modes of nickel porphyrins with the nonplanar deformations of specific symmetries, i.e., static normal coordinate deformations (SNCDs) expressed in terms of irreducible representations of the unperturbed D(4h) point group. The model porphyrins Ni(II) octaethyltet... |
16833284 | Fluorescence anisotropy decay and solvation dynamics in a nanocavity: coumarin 153 in methyl beta-cyclodextrins. | Fluorescence anisotropy decay and solvation dynamics of coumarin 153 (C153) are studied in dimethyl beta-cyclodextrin (DIMEB) and trimethyl beta-cyclodextrin (TRIMEB) nanocavity in water. C153 binds to DIMEB and TRIMEB to form both 1:1 and 1:2 (C153:cyclodextrin) complexes. The anisotropy decays of C153 in DIMEB and TR... |
16817982 | Designing ligands to bind proteins. | The ability to design drugs (so-called 'rational drug design') has been one of the long-term objectives of chemistry for 50 years. It is an exceptionally difficult problem, and many of its parts lie outside the expertise of chemistry. The much more limited problem - how to design tight-binding ligands (rational ligand ... |
16737560 | An extra dimension in nucleic acid sequence recognition. | Watson-Crick base pairing is a natural molecular recognition process that has been exploited in molecular biology and universally adopted in many fields. An additional mode of nucleic acid sequence recognition that could be used in combination with normal base pairing would add an exta dimension to nucleic acid interac... |
16648883 | Below the radar: advanced glycation end products that detour "around the side". Is HbA1c not an accurate enough predictor of long term progression and glycaemic control in diabetes? | Advanced glycation is the irreversible attachment of reducing sugars onto the free amino groups of proteins. Its physiological roles are thought to include the identification of senescent proteins and hence there is a time dependent accumulation of advanced glycation end products (AGEs). AGE labelled proteins are catab... |
16648882 | Biochemical markers of bone turnover: part I: biochemistry and variability. | With the ageing population in most countries, disorders of bone and mineral metabolism are becoming increasingly relevant to every day clinical practice. Consequently, the interest in, and the need for effective measures to be used in the screening, diagnosis and follow-up of such pathologies has markedly grown. Togeth... |
16645742 | Properties of new, long-wavelength, voltage-sensitive dyes in the heart. | Membrane potential measurements using voltage-sensitive dyes (VSDs) have made important contributions to our understanding of electrophysiological properties of multi-cellular systems. Here, we report the development of long wavelength VSDs designed to record cardiac action potentials (APs) from deeper layers in the he... |
16583980 | Comparison of the effect of the R2 phenothiazine ring substituent on fluphenazine and perphenazine interactions with cyclodextrins. | The effect of -CF3 R2 fluphenazine (FLF) and -Cl R2 perphenazine (PF) substituents on interactions of these phenothiazine derivatives with cyclodextrins (CD) was compared. Inclusion complexes of protonated and basic forms of FLF and PF with CDs were obtained in HCl 0.01 mol/L (pH 1.9 or 2.1), in phosphate buffer (pH 5.... |
16515737 | DNA enables nanoscale control of the structure of matter. | Structural DNA nanotechnology consists of constructing objects, lattices and devices from branched DNA molecules. Branched DNA molecules open the way for the construction of a variety of N-connected motifs. These motifs can be joined by cohesive interactions to produce larger constructs in a bottom-up approach to nanoc... |
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