id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
|---|---|---|
18968724 | A piezoelectric quartz crystal sensor array self assembled calixarene bilayers for detection of volatile organic amine in gas. | P-tert-butylcalix[n]arenes (n=4, 6, 8, abbreviated as CA[4], CA[6], CA[8], respectively) were immobilized on the Au surface of the piezoelectric quartz crystal by the reaction between CA[n] and the acid chloride terminated mercaptoacetic acid (MAA) self assembled monolayers to form MAA/CA[n] bilayers. The sensing films... |
18968690 | Equilibrium constant of the gamma-sultone and extraction constant of sodium and potassium ions from water into benzene in presence of 18-crown-6 and bromocresol green. | An extraction procedure for the spectrophotometric determination of sodium or potassium involving a 1:1:1 metal ion: crown ether: sulfonephthalein dye monoanion ion associate has been described in the literature. In a recent paper from this laboratory the total dye content of the organic phase resulting from partitioni... |
16290709 | Investigation on solvent casting films of surfactant-encapsulated clusters. | The surfactant-encapsulated cluster (SEC) composed of a hydrophobic dimethyl dioctadecyl ammonium (DODA) shell and an encapsulated hydrophilic polyoxoanion core can form casting films. The structure of the casting film is influenced by evaporation rates of organic solvent. When the casting films are prepared by slow ev... |
12541917 | [Chiral separation of enantiomers of synthesized amlodipine and its intermediate by capillary electrophoresis]. | A capillary electrophoretic method for the chiral separation of enantiomers of synthesized amlodipine and its intermediate was developed. Several cyclodextrins (CDs) were applied as the chiral selectors and it was found that the ionic modified carboxymethyl-beta-cyclodextrin (CM-beta-CD) could give satisfactory enantio... |
12541913 | Method development of enantiomer separations by affinity capillary electrophoresis, cyclodextrin electrokinetic chromatography and capillary electrophoresis-mass spectrometry. | Capillary electrophoresis (CE) has become a powerful tool for enantiomer separations during the last decade. Since 1993, the author has investigated enantiomer separations by affinity capillary electrophoresis (affinity CE) with some proteins and by cyclodextrin electrokinetic chromatography (CDEKC) with some charged c... |
12503162 | Thermodynamics of hydrogen bond patterns in supramolecular assemblies of water molecules. | The PACHA (Partial Atomic Charges and Hardnesses Analysis) formalism is applied to various supramolecular assemblies of water molecules. After a detailed study of all available crystal structures for ice polymorphs, we shown that the hydrogen bond strength is roughly constant below 1 GPa and considerably weakened above... |
12503158 | Oxophlorin and metallooxophlorin radicals--DFT studies. | A flexible oxophlorin macrocycle, which allows the location of labile hydrogen atoms alternatively at the pyrrole nitrogen, oxygen, or meso-carbon atoms, has been studied by density functional theory (DFT). DFT calculations were carried out on oxophlorin 1, 5-hydroxyporphyrin 2, and two isomers of oxophlorin 3 and 4 (t... |
12503156 | Nonempirical quantification of molecular interactions in supramolecular assemblies. | A new nonempirical scheme for the computation of realistic atomic charges from the sole knowledge of molecular or crystalline structures and of two ab initio parameters per chemical element (a configuration energy and the radius of the most diffuse valence orbital) is presented. Charge distributions obtained from this ... |
12489232 | Anion exchange in the channels of a robust alkaline earth sulfonate coordination network. | The barium sulfonate network presented herein, [[Ba2(L)(H2O)5]Cl]infinity (1), represents the first metal sulfonate compound to possess a cationic framework. The network is layered with channels between pillaring ligands in which chloride ions reside. Compound 1 contracts slightly upon dehydration but retains its overa... |
12489230 | Large oligosaccharide-based glycodendrimers. | Carbohydrate-based dendritic structures composed of 21 and 27 monosaccharide residues have been synthesized in a convergent manner from trisaccharide building blocks. The oligosaccharide AB2 monomers are based on a maltosyl beta(1-->6)galactose structure, which has been modified to include two methylamino groups at the... |
12489223 | Control of the morphogenesis of barium chromate by using double-hydrophilic block copolymers (DHBCs) as crystal growth modifiers. | A systematic morphosynthesis of barium chromate particles has been performed by using double-hydrophilic block copolymers (DHBCs), which consist of a hydrophilic solvating block and a hydrophilic binding block, as crystal growth modifiers to direct the controlled precipitation of barium chromate from aqueous solution. ... |
12489212 | Biodendrimers: new polymeric biomaterials for tissue engineering. | Dendrimers composed entirely of building blocks known to be biocompatible or degradable in vivo to natural metabolites were synthesized using a high yield divergent approach. This synthesis is amenable to the design and development of new biomaterials that are of interest for a variety of medical applications, includin... |
12463721 | Stress-induced decrement in the plasticity of the physical properties of chick brain membranes. | The molecular basis underlying the stress-induced increment in the density of central benzodiazepine receptor from chick forebrain, observed previously at 4 degrees C, was studied from a biophysical perspective. The thermal dependence of [3H]flunitrazepam binding to the central benzodiazepine receptor and the supramole... |
12417049 | Protein folding in the post-genomic era. | Protein folding is a topic of fundamental interest since it concerns the mechanisms by which the genetic message is translated into the three-dimensional and functional structure of proteins. In these post-genomic times, the knowledge of the fundamental principles are required in the exploitation of the information con... |
12382239 | DAPI binding to the DNA minor groove: a continuum solvent analysis. | A continuum solvent model based on the generalized Born (GB) or finite-difference Poisson-Boltzmann (FDPB) approaches has been employed to compare the binding of 4'-6-diamidine-2-phenyl indole (DAPI) to the minor groove of various DNA sequences. Qualitative agreement between the results of GB and FDPB approaches as wel... |
12382238 | Cyclic voltammetry characterization of metal complex imprinted polymer. | Polymer capable of specific binding to Cu(2+)-2, 2'-dipyridyl complex was prepared by molecular imprinting technology. The binding specificity of the polymer to the template (Cu(2+)-2, 2'-dipyridyl complex) was investigated by cyclic voltammetric scanning using the carbon paste electrode modified by polymer particles i... |
12382237 | Peptide biosensor for recognition of cross-species cell surface markers. | Biosensors based on phage display-derived peptides as biorecognition molecules were used for the detection of cell surface cross-species markers in tissue homogenates. The peptide selected for murine myofibers was immobilized onto the surface of an acoustic wave sensor by biotin-streptavidin coupling. To detect peptide... |
12382236 | tRNA discrimination by T. thermophilus phenylalanyl-tRNA synthetase at the binding step. | The extent of tRNA recognition at the level of binding by Thermus thermophilus phenylalanyl-tRNA synthetase (PheRS), one of the most complex class II synthetases, has been studied by independent measurements of the enzyme association with wild-type and mutant tRNA(Phe)s as well as with non-cognate tRNAs. The data obtai... |
12382235 | Terminal alpha-linked galactose rather than N-acetyl lactosamine is ligand for bovine heart galectin-1 in N-linked oligosaccharides of glycoproteins. | Preference for the beta-anomer of galactose attributed to the bovine heart 14 kDa galectin-1 (BHL-14) was re-examined using natural glycoproteins and artificially glycosylated proteins as ligands. Endogenous glycoproteins co-purified with BHL-14 during its affinity chromatographic isolation contained oligosaccharides b... |
12382234 | Molecular determinants of the hanatoxin binding in voltage-gated K+-channel drk1. | The carboxyl terminus of S3 segment (S3(C)) in voltage-gated potassium channels was proposed to bear the binding site for gating modifier toxins like Hanatoxin and a helical secondary structural arrangement was suggested. Due to the lack of complete structure in high resolution for such a channel molecule, no further d... |
12324997 | Amyloid architecture: complementary assembly of heterogeneous combinations of three or four peptides into amyloid fibrils. | The amyloid fibril is a misfolded and undesirable state for proteins that has been proposed to be a causative agent for a variety of fatal diseases known as amyloid diseases, such as Alzheimer's and prion diseases. However, the fibril has a highly ordered tertiary structure in which numerous beta-strand polypeptide cha... |
12244715 | [In vitro self assembly of supermolecular structures after spontaneous disassembly of carotovoricins]. | The self-assembly of supramolecular structures (empty sheaths and polysheaths of the macromolecular Erwinia carotovora bacteriocins) was studied by electron microscopy in the course of 1- to 2-year incubation of phage particles at 4 degrees C. This study showed that the empty sheaths and polysheaths of the bacteriocins... |
12222968 | The 2.4-A crystal structure of the penicillin-resistant penicillin-binding protein PBP5fm from Enterococcus faecium in complex with benzylpenicillin. | Penicillin-binding proteins (PBPs) are membrane proteins involved in the final stages of peptidoglycan synthesis and represent the targets of beta-lactam antibiotics. Enterococci are naturally resistant to these antibiotics because they produce a PBP, named PBP5fm in Enterococcus faecium, with low-level affinity for be... |
12222963 | Assembling the human immunodeficiency virus type 1. | Retroviral assembly proceeds through a series of concerted events that lead to the formation and release of infectious virion particles from the infected cell. Upon translation, structural proteins are targeted to the plasma membrane where they accumulate. There, the nascent particle forces the plasma membrane to form ... |
12222961 | The short proline-rich antibacterial peptide family. | From the many peptide families that are induced upon bacterial infection and can be isolated from all classes of animals, the short, proline-rich antibacterial peptides enjoy particular interest. These molecules were shown to inactivate an intracellular biopolymer in bacteria without destroying or remaining attached to... |
12222958 | New insights into the structure and function of fatty acid-binding proteins. | Fatty acid-binding proteins (FABPs) are members of a superfamily of lipid-binding proteins, and occur intracellularly in vertebrates and invertebrates. This review presents recent findings on the diversity of these FABPs and their proposed roles in fatty acid (FA) metabolism and other cellular processes. Special attent... |
12210243 | Design and performance of a microchip electrophoresis instrument with sensitive variable-wavelength fluorescence detection. | A modular instrument for high-speed microchip electrophoresis (MCE) equipped with a sensitive variable-wavelength fluorescence detection system was developed and evaluated. The experimental setup consists mainly of a lamp-based epifluorescence microscope for variable-wavelength fluorescence detection and imaging and a ... |
12210233 | Decreased protein peak asymmetry and width due to static capillary coating with hydrophilic derivatives of polydimethylacrylamide. | We have recently described [1] a fast and simple method for the "adsorbed static" coating of capillaries in capillary zone electrophoresis (CZE) with epoxy-poly(dimethylacrylamide) (EPDMA). Protein CZE peaks in the EPDMA-coated capillaries exhibited a peak asymmetry similar to that obtained in capillaries with "covalen... |
12204416 | Inclusional complex study between 6-p-toluidinylnaphthalene-2-sulfonate and 2-hydroxypropyl-beta-cyclodextrin. | 6-p-Toluidinylnaphthalene-2-sulfonate (TNS) is used as a fluorescent probe for exploring hydrophobic regions of several biological substances, such as proteins, and studying solution state folding behaviour. The current study examines the complexation of TNS with 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) in aqueous ... |
12206500 | Circular dichroism spectra of regioregular poly[3 [(S)-2-methylbutyl]-thiophene] and of poly[3,4-di[(S)-2-methylbutyl]-thiophene]. | Ultraviolet absorption and Circular Dichroism spectra in the region 300-700 nm for highly regioregular samples of Poly[3[(S)-2-methylbutyl]-thiophene] are reported for solutions in good and poor solvents, at variable temperature, and for films in various conditions. In the latter case novel CD data up to the melting te... |
12203349 | Completely spirocyclopropanated macrocyclic oligodiacetylenes and their permethylated analogues: preparation and properties. | The acyclic dehydrotrimer (12) and -hexamer (28) of 1,1-diethynyl-2,2,3,3-tetramethylcyclopropane were prepared from 1-chloro-1-(trimethylsilylethynyl)-2,2,3,3-tetramethylcyclopropane (4) in six and nine steps, respectively, in 36 and 8 % overall yield, respectively, using Cadiot-Chodkiewicz or Hay coupling procedures ... |
12203348 | Syntheses, crystal structures, and physical properties of dinuclear copper(I) and tetranuclear mixed-valence copper(I,II) complexes with hydroxylated bipyridyl-like ligands. | Four copper complexes with hydroxylated bipyridyl-like ligands, namely [Cu(2)(ophen)(2)] (1), [Cu(4)(ophen)(4)(tp)] (2), [Cu(4)(obpy)(4)(tp)] (3), and [Cu(4)(obpy)(4)(dpdc)].2H(2)O (4), (Hophen=2-hydroxy-1,10-phenanthroline, Hobpy=6-hydroxy-2,2'-bipyridine, tp=terephthalate, dpdc=diphenyl-4,4'-dicarboxylate) have been ... |
12203346 | Triarylpyridinium-functionalized terpyridyl ligand for photosensitized supramolecular architectures: intercomponent coupling and photoinduced processes. | The electronic (absorption spectra) and electrochemical properties of a novel series of triphenylpyridinium (H(3)TP(+)=A) electron-acceptor-based polyad species have been correlated with their steady-state (emission spectra) and time-resolved (ns and ps laser flash photolysis) photophysical behavior (at both 293 and 77... |
12203344 | Calix[6]pyrrole and hybrid calix[n]furan[m]pyrroles (n+m=6): syntheses and host-guest chemistry. | Calix[6]pyrrole 2 and the "hybrid systems" calix[3]furan[3]pyrrole 12, calix[2]furan[4]pyrrole 13, and calix[1]furan[5]pyrrole 14, have been synthesized by increasing conversion of the furan units present in the readily accessible calix[6]furan 3 to pyrroles. The host-guest chemistry of these novel macrocycles towards ... |
12189880 | Photosensitized production of doubly reduced methylviologen followed by highly efficient methylviologen radical formation using self-assembling ruthenium(II) complexes. | Supramolecular fibers of Ru(II) complexes act as efficient photosensitizers, photochemically generating methylviologen radical (MV.+) and then converting it quantitatively to doubly reduced methylviologen, (MV0), in the presence of triethanolamine. |
12189867 | A highly water-soluble 2:1 beta-cyclodextrin-fullerene conjugate. | A novel 2:1 (permethylated-beta-cyclodextrin)-fullerene conjugate has been synthesised; highly soluble in cold water with formation of aggregates, it displays a negative solubility coefficient and has a partition coefficient between octanol and water (Log P = 1.58) in the suitable range for biological studies. |
12184623 | Quantitative approach for the screening of cyclodextrins by nuclear magnetic resonance spectroscopy in support of chiral separations in liquid chromatography and capillary electrophoresis enantioseparation of norgestrel with alpha-, beta- and gamma-cyclodextrins. | A quantitative NMR approach is proposed for the screening of cyclodextrins with regard to their enantioselectivity as chiral mobile phase additives in column reversed-phase chromatography and capillary electrophoresis. Similarities and differences between the mechanism of enantiomeric peak-separation in NMR and HPLC an... |
12180548 | The lower-generation polypropylenimine dendrimers are effective gene-transfer agents. | <h4>Objective</h4>To evaluate polypropylenimine dendrimers (generations 1-5: DAB 4, DAB 8, DAB 16, DAB 32, and DAB 64) as gene delivery systems.<h4>Methods</h4>DNA binding was evaluated by measuring the reduced fluorescence of ethidium bromide, and molecular modelling of dendrimer-DNA complexes also was performed. Cell... |
12175303 | Coupling of optical characterization with particle and network synthesis for biomedical applications. | Polymeric microspheres containing a magnetic core have been used in cancer therapy for biophysical targeting of antitumor agents and in magnetic resonance imaging as contrasting agents. For the Human Genome Project, deoxyribose nucleic acid (DNA) capillary electrophoresis has become the most widely used analytical tech... |
12173655 | Double-armed crown ethers: synergic pi-coordination effect on potentiometric sensing for Ag(I). | Three diaza-18-crown-6 derivatives having methyl (L1), methoxy (L2) and phenyl (L3) end-groups in para-substituted phenolic side-arms have been investigated as potentiometric sensing materials for silver(I)-selective poly(vinyl chloride) membrane electrodes. The aim of the present work is to establish whether a combina... |
12171652 | Low-temperature sensors in bacteria. | Bacteria are ubiquitous colonizers of various environments and host organisms, and they are therefore often subjected to drastic temperature alterations. Temperature alterations set demands on these colonizers, in that the bacteria need to readjust their biochemical constitution and physiology in order to survive and r... |
12166646 | Ribosomal proteins mediate the hepatitis C virus IRES-HeLa 40S interaction. | Translation of the hepatitis C virus genomic RNA is mediated by an internal ribosome entry site (IRES). The 330-nt IRES RNA forms a binary complex with the small 40S ribosomal subunit as a first step in translation initiation. Here chemical probing and 4-thiouridine-mediated crosslinking are used to characterize the in... |
12166645 | Trans-acting RNA inhibits tRNA suppressor activity in vivo. | We constructed two aptamers, each of which contains a 7-nt-long loop complementary to the anticodon loop of a suppressor tRNA. One of these aptamers can form a stable bimolecular complex with the suppressor tRNA in vitro and protects the 7 nt in the suppressor's anticodon loop from RNase S1. An Escherichia coli strain,... |
12164212 | Recent results of biotransformation of drugs: investigation of the in vitro biotransformation of thalidomide using a dual cyclodextrin system in capillary electrophoresis. | A previously developed capillary electrophoresis method for the simultaneous separation and enantioseparation of thalidomide (TD) and its hydroxylated metabolites was extended to one additional biotransformation product. The dual chiral selector system using native beta-cyclodextrin (beta-CD) and the negatively charged... |
12153302 | Synthesis of new polymer-bound adenine nucleotides using starburst PAMAM dendrimers. | Two types of new polymer-bound adenine nucleotides were synthesized by coupling adenine nucleotides (ATP and ADP) with starburst polyamidoamine (PAMAM) dendrimers. The first type was obtained by coupling native adenine nucleotides directly with a carboxy-terminated PAMAM dendrimer. In the second type, the nucleotides w... |
12148809 | Alkali metal mediated resorcarene capsules: an ESI-FTICRMS study on gas-phase structure and cation binding of tetraethyl resorcarene and its per-methylated derivative. | Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) with additional ab initio calculations were used to examine the alkali metal cation binding selectivity (i.e., molecular recognition) and host properties of tetraethyl resorcarene (1) and its per-methylated derivative (2).... |
12144925 | Natural supramolecular building blocks. Cysteine-added mutants of cowpea mosaic virus. | Wild-type Cowpea mosaic virus (CPMV) displays no cysteine side chains on the exterior capsid surface and is therefore relatively unreactive with thiol-selective reagents. Four CPMV mutants bearing cysteine residues in one of two exterior positions of the asymmetric unit were created. The mutants were shown to aggregate... |
12144924 | Natural supramolecular building blocks. Wild-type cowpea mosaic virus. | Cowpea mosaic virus (CPMV) can be isolated in gram quantities, possesses a structure that is known to atomic resolution, and is quite stable. It is therefore of potential use as a molecular entity in synthesis, particularly as a building block on the nanochemical scale. CPMV was found to possess a lysine residue with e... |
12144922 | A semisynthetic glutathione peroxidase with high catalytic efficiency. Selenoglutathione transferase. | Glutathione peroxidase (GPX) protects cells against oxidative damage by catalyzing the reduction of hydroperoxides by glutathione (GSH). GPX therefore has potential therapeutic value as an antioxidant, but its pharmacological development has been limited because GPX uses a selenocysteine as its catalytic group and it i... |
12144921 | Skipping in a hybrid polyketide synthase. Evidence for ACP-to-ACP chain transfer. | A tetraketide synthase containing a loading module (LM), the extension modules erythromycin module 1, rapamycin module 2, and erythromycin module 2 (LM-Ery1-Rap2-Ery2-TE), when expressed in Saccharopolyspora erythraea strain JC2, produced as previously reported a mixture of tetraketide lactones (minor products) and tri... |
12142534 | Selection and amplification of hosts from dynamic combinatorial libraries of macrocyclic disulfides. | We have discovered two receptors for two different guests from a single dynamic combinatorial library. Each of the two guests amplifies the formation of a tightly binding host at the expense of unfit library members. Small differences in host-guest binding translate into useful differences in amplification. The selecte... |
12141672 | Nanostructured microcantilevers with functionalized cyclodextrin receptor phases: self-assembled monolayers and vapor-deposited films. | It is shown that the performance of microcantilver-based chemical sensors in a liquid environment is affected by altering cantilever surface morphology and receptor phase type and thickness. Self-assembled monolayers of thiolated beta-cyclodextrin (HM-beta-CD) and thin films of vapor-deposited heptakis (2,3-O-diacetyl-... |
12141658 | Use of a modified cyclodextrin host for the enantioselective detection of a halogenated diether as chiral guest via optical and electrical transducers. | In an alkaline rebreathing circuit, the inhalation anesthetic sevoflurane degrades into at least two products, one of them being the chiral halodiether 1,1,1,3,3-pentafluoro-2-(fluoromethoxy)-3-methoxypropane (halodiether B). Using octakis(3-O-butanoyl-2,6-di-O-n-pentyl)-y-cyclodextrin (Lipodex E) as chiral host dilute... |
12140553 | Synthetic hosts by monomolecular imprinting inside dendrimers. | Synthetic host systems capable of selectively binding guest molecules are of interest for applications ranging from separations and chemical or biological sensing to the development of biomedical materials. Such host systems can be efficiently prepared by 'imprinting' polymers or inorganic materials with template molec... |
12139065 | Dual-chemiresistor GC detector employing monolayer-protected metal nanocluster interfaces. | The synthesis and testing of two gold-thiolate monolayer-protected (nano)clusters as interfacial layers on a dual-chemiresistor vapor sensor array are described. Responses (changes in dc resistance) to each of 11 organic solvent vapors are rapid, reversible, and linear with concentration at low vapor concentrations, be... |
12137545 | Supramolecular cation assemblies of hydrogen-bonded (NH4+/NH2NH3+)(crown ether) in [Ni(dmit)2]-based molecular conductors and magnets. | Hydrogen-bonded supramolecular cation assemblies of (NH4+/NH2-NH3+)(crown ether), where the crown ether is [12]crown-4, [15]crown-5, or [18]crown-6, were incorporated into electrically conducting [Ni(dmit)2] salts (dmit2- = 2-thioxo-1,3-dithiole-4,5-dithiolate). (NH4+)([12]crown-4)[Ni(dmit)2]3(CH3CN)2 had a pyramidal s... |
12137544 | Crystal engineering for topochemical polymerization of muconic esters using halogen-halogen and CH/pi interactions as weak intermolecular interactions. | We now report the molecular and crystal structure design of muconic ester derivatives on the basis of crystal engineering using halogen-halogen contacts and CH/pi interactions. The solid-state photoreaction pathway of the dibenzyl (Z,Z)-muconates as the 1,3-diene dicarboxylic acid monomers depends on the structure of t... |
12137542 | Peptide dendrimers based on polyproline helices. | We present a new family of peptide dendrimers based on polyproline helices and cis-4-amino-L-proline as a branching unit. Dendrimers were synthesized by a convergent solid-phase peptide synthesis approach. The conformational transition between polyproline type I helix and polyproline type II helix was observed by circu... |
12136094 | The role of template-primer in protection of reverse transcriptase from thermal inactivation. | We compared the thermal stabilities of wild-type recombinant avian myeloblastosis virus (AMV) and Moloney murine leukemia virus (M-MLV) reverse transcriptase (RT) with those of mutants of the recombinant enzymes lacking RNase H activity. They differed in resistance to thermal inactivation at elevated temperatures in th... |
12136085 | Functional interaction between TATA and upstream CACGTG elements regulates the temporally specific expression of Otx mRNAs during early embryogenesis of the sea urchin, Hemicentrotus pulcherrimus. | The orthodenticle-related protein (HpOtx) gene derived from the sea urchin Hemicentrotus pulcherrimus encodes two distinct isoforms, HpOtxE and HpOtxL, which are differentially expressed during early embryogenesis and are driven by TATA-less and TATA-containing promoters, respectively. In order to determine if the TATA... |
12136019 | Targeted chromosomal cleavage and mutagenesis in Drosophila using zinc-finger nucleases. | Zinc-finger nucleases (ZFNs) are hybrids between a nonspecific DNA-cleavage domain and a DNA-binding domain composed of Cys(2)His(2) zinc fingers. Because zinc fingers can be manipulated to recognize a broad range of sequences, these enzymes have the potential to direct cleavage to arbitrarily chosen targets. We have t... |
12132882 | Assessment of the macrocyclic effect for the complexation of crown-ethers with alkali cations using the Substructural Molecular Fragments method. | The Substructural Molecular Fragments method (Solov'ev, V. P.; Varnek, A. A.; Wipff, G. J. Chem. Inf. Comput. Sci. 2000, 40, 847-858) was applied to assess stability constants (logK) of the complexes of crown-ethers, polyethers, and glymes with Na+, K+, and Cs+ in methanol. One hundred forty-seven computational models ... |
12132932 | Synthesis and study of Ru,Rh,Ru triads: modulation of orbital energies in a supramolecular architecture. | Supramolecular trimetallic complexes [((tpy)RuCl(BL))(2)RhCl(2)](3+) where tpy = 2,2':6',2' '-terpyridine and BL = dpp or bpm [dpp = 2,3-bis(2-pyridyl)pyrazine and bpm = 2,2'-bipyrimidine] have been synthesized and characterized. The mixed-metal complexes couple a reactive rhodium(III) center to two ruthenium(II) light... |
12132929 | Metalla-supramolecular rectangles as electron reservoirs for multielectron reduction and oxidation. | The electron-transfer capacity of molecular rectangle ions [Pt(II)(4)(PEt(3))(8)(mu-anth(2-))(2)(mu-L)(2)](4+) with anth = anthracene-1,8-diyl and L = 4,4'-bipyridine (bp) or 1,2-bis(4-pyridyl)ethene (bpe) was investigated in acetonitrile and dichloromethane using cyclic voltammetry, EPR, and UV-vis-near-IR spectroelec... |
12132928 | Mechanistic studies of a calcium-dependent MRI contrast agent. | Intracellular Ca(2+) plays an important role in signal transduction, and we are developing new MRI techniques to study its regulation in living animals. We have reported on an MRI contrast agent (DOPTA-Gd) where the relaxivity of the complex is controlled by the presence or absence of the divalent ion Ca(2+). By struct... |
12132926 | Alkyl and aryl substituted corroles. 3. Reactions of cofacial cobalt biscorroles and porphyrin-corroles with pyridine and carbon monoxide. | The synthesis and characterization of three new cofacial biscorroles and three new linked Co(II) porphyrins and Co(III) corroles with the same face to face orientation are described. The biscorroles are represented as (BCS)Co(2), (BCO)Co(2), (BCX)Co(2) while the porphyrin-corrole dyads are represented as (PCA)Co(2), (P... |
12132903 | DNA photocleavage by a supramolecular Ru(II)-viologen complex. | A novel Ru(II) complex possessing two sequentially linked viologen units, Ru-V(1)-V(2)(6+), was synthesized and characterized. Upon excitation of the Ru(II) unit (lambda(exc) = 532 nm, fwhm approximately 10 ns), a long-lived charge-separated (CS) state is observed (tau = 1.7 micros) by transient absorption spectroscopy... |
12126408 | Synthesis of polysubstituted benzothiophenes and sulfur-containing polycyclic aromatic compounds via samarium diiodide promoted three-component coupling reactions of thiophene-2-carboxylate. | By the promotion of samarium diiodide, thiophene-2-carboxylate reacted with 2 equiv of ketones at the C-4 and C-5 positions to give diols such as 2 and 9. Because the intermediary organosamarium species were oxophilic but not too basic, the double hydroxyalkylations with various ketone substrates, including alkyl aryl ... |
12126389 | Catalytic oxidations of steroid substrates by artificial cytochrome p-450 enzymes. | Catalysts comprising manganese-porphyrins carrying cyclodextrin binding groups are able to perform hydroxylations with substrate selectivity and regio- and stereoselectivity and high catalytic turnovers. The geometries of the catalyst/substrate complexes override intrinsic substrate reactivities, permitting attack on g... |
12126625 | Structural basis of the adaptive molecular recognition by MMP9. | Matrix metalloproteinase (MMPs) are critical for the degradation of extracellular matrix components and, therefore, need to be regulated tightly. Almost all MMPs share a homologous C-terminal haemopexin-like domain (PEX). Besides its role in macromolecular substrate processing, the PEX domains appear to play a major ro... |
12125583 | Crystal engineering of metalloporphyrin assemblies. New supramolecular architectures mediated by bipyridyl ligands. | Targeted synthesis of new supramolecular motifs of metalloporphyrins in crystals by a concerted mechanism of molecular recognition in three dimensions, aided by organic ligands, is presented; it involves induced assembly of [tetrakis(4-hydroxyphenyl)porphyrinato]zinc species by a combination of axial coordination throu... |
12125822 | Increasing the efficiency of heterologous promoters in actinomycetes. | An Escherichia coli-actinomycete shuttle vector, pCJW93, was constructed which places cloned genes under the control of the thiostrepton-inducible tip promoter from Streptomyces lividans. We also constructed expression vectors bearing the actII-ORF4/PactI activator-promoter system of the actinorhodin biosynthetic pathw... |
12123366 | Study of alpha-crustacyanin utilizing halogenated canthaxanthins. | [structure: see text] The preparations and spectroscopic characteristics of five all-trans halogenated canthaxanthins are described in this letter. The air/light-sensitive halogenated canthaxanthins were used to study alpha-crustacyanin, a blue astaxanthin-protein complex, which is isolated from the carapace of the lob... |
12123351 | Electrochemical recognition of cations by bis(pyrrolo)tetrathiafulvalene macrocycles. | [structure: see text] Tetrathiafulvalene redox-responsive ligands devoid of cis/trans isomerism containing the electroactive bis(pyrrolo[3,4-d])tetrathiafulvalene moiety and polyether subunits have been synthesized. One ligand exhibits high binding affinities for Pb2+ and Ba2+ cations as shown by independent methods (1... |
12122055 | Stomatin-related olfactory protein, SRO, specifically expressed in the murine olfactory sensory neurons. | We identified a stomatin-related olfactory protein (SRO) that is specifically expressed in olfactory sensory neurons (OSNs). The mouse sro gene encodes a polypeptide of 287 amino acids with a calculated molecular weight of 32 kDa. SRO shares 82% sequence similarity with the murine stomatin, 78% with Caenorhabditis eleg... |
12121793 | Supramolecular structures of metronidazole and its copper(II), cobalt(II) and zinc(II) coordination compounds. | In this work we present the synthesis and structural and spectroscopic characterization of Cu(II), Co(II) and Zn(II) coordination compounds with the antibiotic metronidazole ([double bond]emni). Coordination to metal ions is through its imidazolic nitrogen, while the hydroxyethyl and nitro groups act as supramolecular ... |
12121785 | DNA-binding and cleavage studies of macrocyclic copper(II) complexes. | Three hexaaza macrocyclic copper (II) complexes with different functional groups have been synthesized and characterized by elemental analysis and infrared spectra. Absorption and fluorescence spectral, cyclic voltammetric and viscometric studies have been carried out on the interaction of [CuL(1)]Cl(2) (L(1)[double bo... |
12121779 | Aryl substituted ruthenium bis-terpyridine complexes: intercalation and groove binding with DNA. | The non-covalent interaction of five novel ruthenium(II) bis-terpyridine complexes with calf thymus DNA and, where appropriate, with poly[d(G-C)](2) and poly[d(A-T)](2) is described. Each complex is functionalised with aryl tail groups in the 4' position of the terpyridine ligands ((i) 9-anthracenyl, (ii) 4,4'-biphenyl... |
12121108 | Organometallic dendrimers based on (tetraphenylcyclobutadiene)cyclopentadienylcobalt modules. | The synthesis and characterization of novel organometallic polyphenylene dendrimers containing 24 or 44 phenyl rings and one cyclobutadiene(cyclopentadienyl)cobalt unit is reported. The dendrimers are made by the convergent CpCo(CO)(2)-mediated dimerization of di- or tetraethynyltolanes followed by a divergent core ext... |
12121102 | Molecular packing and morphology of oligo(m-phenylene ethynylene) foldamers. | Understanding and controlling solid-state morphologies and molecular conformations is the key to optimizing the properties of materials. As an example for the influence of small chemical changes on solid-state structures, we studied oligo(m-phenylene ethynylene) foldamers, where the introduction of an endo-methyl group... |
12121085 | Excited-state symmetry breaking in cofacial and linear dimers of a green perylenediimide chlorophyll analogue leading to ultrafast charge separation. | Photoexcitation of chromophoric dimers constrained to a symmetric pi-stacked geometry by their molecular structure usually produces excimers independent of solvent polarity, while dimers with edge-to-edge perpendicular pi systems undergo excited-state symmetry breaking in highly polar solvents leading to intradimer cha... |
12120821 | Therapeutic applications of monoclonal antibodies. | Researchers have sought therapeutic applications for monoclonal antibodies since their development in 1975. However, murine-derived monoclonal antibodies may cause an immunogenic response in human patients, reducing their therapeutic efficacy. Chimeric and humanized antibodies have been developed that are less likely t... |
12119342 | Identification of the lateral interaction surfaces of human histocompatibility leukocyte antigen (HLA)-DM with HLA-DR1 by formation of tethered complexes that present enhanced HLA-DM catalysis. | Human histocompatibility leukocyte antigen (HLA)-DM is a major histocompatibility complex (MHC)-like protein that catalyzes exchange of antigenic peptides from MHC class II molecules. To investigate the molecular details of this catalysis we created four covalent complexes between HLA-DM and the MHC class II allele DR1... |
12118993 | Polymeric materials containing bile acids. | Bile acids are biological compounds in the body that have interesting properties and have been used to make special chemical structures in molecular recognition. Various polymers have been synthesized from bile acids. The materials should preserve some of the properties of bile acids, such as biocompatibility, high sta... |
12115827 | Development and in vivo evaluation of buccal tablets prepared using danazol-sulfobutylether 7 beta-cyclodextrin (SBE 7) complexes. | The aim of the present work was to develop a mucoadhesive controlled-release formulation of danazol-sulfobutylether 7 beta-cyclodextrin (SBE 7) complex and to evaluate the feasibility of improving the bioavailability of danazol via the buccal route. Different types of polymers, polycarbophil (PC) and hydroxypropylmethy... |
12111804 | Proteins of peripheral myelin are associated with glycosphingolipid/cholesterol-enriched membranes. | A characteristic feature of the vertebrate nervous system is the ensheathment of axons by myelin, a multilamellar membrane specialization produced by polarized glial cells. Although the main protein and lipid components of the myelin sheath are well characterized, relatively little is known about the mechanisms of thei... |
12110600 | Accessory factors determine the order of strand exchange in Xer recombination at psi. | Xer site-specific recombination in Escherichia coli converts plasmid multimers to monomers, thereby ensuring their correct segregation at cell division. Xer recombination at the psi site of plasmid pSC101 is preferentially intramolecular, giving products of a single topology. This intramolecular selectivity is imposed ... |
12112336 | Molecular recognition in solid-state crystallization: colored chiral adduct formations of 1,1'-bi-2-naphthol derivatives and benzoquinone with a third component. | Molecular recognition in solid-state crystallization involving derivatives of 1,1'-bi-2-naphthol and benzoquinone was studied. No adduct crystal was formed when crystals of biphenyl were further added as a third component to a grinding mixture of crystals of chiral 1,1'-bi-2-naphthol and benzoquinone, which by itself d... |
12112331 | Mechanism of asymmetric hydrogenation by rhodium complexes with unsymmetrical P-chirogenic bisphosphine ligands. | Using a series of the rhodium complexes with (1S,2S)-1-(R(1))methylphosphino-2-(R(2))(R(3))phosphinoethane (R(1), R(2) and R(3) = 1-adamantyl, t-butyl, cyclohexyl, cyclopentyl, methyl; abbreviated as unsymmetrical BisP*), very high enantioselectivities were observed when the di- or tri- substituted and tetra-substitute... |
12112327 | Chirality induction in supramolecular aggregate: chiral recognition between armed cyclen-Na+ complexes having quadruplicated helical geometry. | A water-soluble self-aggregate of octadentate Na+ complex with chiral cholesterol-armed cyclen provides unique microenvironments for chirality induction of guest cyclen-Na+ complex via supramolecular interaction. |
12110198 | Structure of the complex of heptakis(2,6-di-O-methyl)-beta-cyclodextrin with (2,4-dichlorophenoxy)acetic acid. | The structure of the complex formed by heptakis(2,6-di-O-methyl)-beta-cyclodextrin and (2,4-dichlorophenoxy)acetic acid was studied by X-ray diffraction. The dichlorophenyl moiety of the guest molecule was found outside the host hydrophobic cavity in the primary methoxy groups region whereas the oxyacetic acid chain pe... |
12093920 | Crystal structure of human cytomegalovirus IL-10 bound to soluble human IL-10R1. | Human IL-10 (hIL-10) modulates critical immune and inflammatory responses by way of interactions with its high- (IL-10R1) and low-affinity (IL-10R2) cell surface receptors. Human cytomegalovirus exploits the IL-10 signaling pathway by expressing a functional viral IL-10 homolog (cmvIL-10), which shares only 27% sequenc... |
12093904 | Direct visualization of distinct T cell epitopes derived from a melanoma tumor-associated antigen by using human recombinant antibodies with MHC- restricted T cell receptor-like specificity. | Specificity in the cellular immune system is controlled and regulated by the T cell antigen receptor (TCR), which specifically recognizes peptide/major histocompatibility complex (MHC) molecules. In recent years many cancer-associated MHC-restricted peptides have been isolated and because of their highly restricted fin... |
12105922 | Mutual control of axial and equatorial ligands: model studies with [Ni]-bacteriochlorophyll-a. | Modification of the metal's electronic environment by ligand association and dissociation in metalloenzymes is considered cardinal to their catalytic activity. We have recently presented a novel system that utilizes the bacteriochlorophyll (BChl) macrocycle as a ligand and reporter. This system allows for charge mobili... |
12105920 | Nitride formation by thermolysis of a kinetically stable niobium dinitrogen complex. | The reduction of [P(2)N(2)]NbCl (where [P(2)N(2)] = PhP(CH(2)SiMe(2)NSiMe(2)CH(2))(2)PPh) with KC(8) under a dinitrogen atmosphere generates the paramagnetic dinuclear dinitrogen complex ([P(2)N(2)]Nb)(2)(mu-N(2)) (2). Complex 2 has been characterized crystallographically and by EPR spectroscopy. Variable-temperature m... |
12105911 | Binding of acetylcholine and tetramethylammonium to a cyclophane receptor: anion's contribution to the cation-pi interaction. | The interaction of the lipophilic cyclophane 1 with several acetylcholine (ACh) and tetramethylammonium (TMA) salts has been investigated in deuteriochloroform to ascertain the influence of the counterion on the cation-pi interaction. Reliable association constants have been measured for 17 salts of commonly used anion... |
12105910 | Diastereoselective formation of glycoluril dimers: isomerization mechanism and implications for cucurbit[n]uril synthesis. | Cucurbit[6]uril (CB[6]) is a macrocyclic compound, prepared in one pot from glycoluril and formaldehyde, whose molecular recognition properties have made it the object of intense study. Studies of the mechanism of CB[n] formation, which might provide insights that allow the tailor-made synthesis of CB[n] homologues and... |
12105909 | Binding efficiency and transport properties of molecularly imprinted polymer thin films. | A model system for the characterization of molecular recognition events in molecularly imprinted polymers (MIPs) is presented. The use of a biologically inspired, three-point hydrogen-bonding motif and a thin film polymeric matrix allows for pre- and post-polymerization binding properties to be characterized by infrare... |
12105908 | A dendrimer-based electron antenna: paired electron-transfer reactions in dendrimers with a 4,4'-bipyridine core and naphthalene peripheral groups. | Paired electron transfers (ET) induced by the absorption of two photons by synthetic dendrimers are observed in first-, second-, and third-generation dendrimers comprised of a viologen-like core and an array of naphthalene peripheral groups. Flash photolysis and transient absorption techniques show that the yield of ph... |
12105948 | Determination of monoterpene hydrocarbons and alcohols in Majorana hortensis Moench by micellar electrokinetic capillary chromatographic. | Micellar electrokinetic capillary chromatography was used to determine the essential oils obtained by steam distillation of different samples of marjoram (Majorana hortensis Moench) dried leaves and flowers. The electrophoretic method consisted of a running buffer of 10 mM NaH2PO4, 6 mM Na2B4O7, 50 mM SDS, 7 mM gamma-c... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.