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12913241 | Cyclodextrin-enclosed substances of Brazilian propolis. | By using beta-cyclodextrin-inclusion as a unique technique, an efficient separation of pharmacologically active phenolic compounds from Brazilian propolis was achieved to provide one new compound, 3-(3-hydroxy-3-methyl-butyl)-5-prenyl-4-hydroxycinnamic acid, together with two common cinnamic acid derivatives, artepilli... |
12913237 | Reaction of magnesium alkylidene carbenoids with lithium alpha-sulfonyl carbanions: a novel synthesis of tri- and tetra-substituted allenes from 1-chlorovinyl p-tolyl sulfoxides and sulfones. | Treatment of 1-chlorovinyl p-tolyl sulfoxides, which were synthesized from ketones and chloromethyl p-tolyl sulfoxide, with ethylmagnesium chloride or isopropylmagnesium chloride at below -78 degrees C gave magnesium alkylidene carbenoids in about 90% yields. The reaction of the generated carbenoids with lithium alpha-... |
12913230 | Fentanyl and its analogue N-(1-phenylpyrazol-3-yl)-N-[1-(2-phenylethyl)-4-piperidyl]propanamide: 1H- and 13C-NMR spectroscopy, X-ray crystallography, and theoretical calculations. | The oxalate salts and free bases of fentanyl and N-[1-(2-phenylethyl)-4-piperidyl]-N-(1-phenyl-4-pyrazolyl)propanamide, a new lead compound for long-acting analgesia, have been characterized by (1)H- and (13)C-NMR spectroscopy. The crystal structure of the hydrochloride of N-[1-(2-phenylethyl)-4-piperidyl]-N-(1-phenyl-... |
12913228 | Investigation and physicochemical characterization of vinpocetine-sulfobutyl ether beta-cyclodextrin binary and ternary complexes. | The purpose of this study was to investigate the interactions between vinpocetine (VP), sulfobutyl ether beta-cyclodextrin (SBEbetaCD) and the water-soluble polymers polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC). The water-soluble polymers were shown to improve the complexation efficiency of SBEbe... |
12911315 | BlmIII and BlmIV nonribosomal peptide synthetase-catalyzed biosynthesis of the bleomycin bithiazole moiety involving both in cis and in trans aminoacylation. | Cloning and sequence analysis of the bleomycin (BLM) biosynthetic gene cluster predicted that the two nonribosomal peptide synthetases (NRPSs), BlmIV and BlmIII, are responsible for the biosynthesis of the BLM bithiazole moiety. BlmIV is a seven domain (C(2)-A(2)-PCP(2)-Cy(1)-A(1)-PCP(1)-Cy(0)) NRPS, and BlmIII is a th... |
12908957 | A comparative study of the ability of different techniques to extract menthol from Mentha piperita. | Supercritical fluid extraction, direct thermal desorption, hydroalcoholic extraction, and atomization are used to extract menthol from leaf plants of Mentha piperita. The investigated methods are comparatively evaluated on the basis of their reliability to determine the enantiomeric distribution of menthol. The enantio... |
12907742 | Combination of DNA-directed immobilization and immuno-PCR: very sensitive antigen detection by means of self-assembled DNA-protein conjugates. | An assay for very sensitive antigen detection is described which takes advantage of the self- assembly capabilities of semi-synthetic conjugates of DNA and proteins. The general scheme of this assay is similar to a two-sided (sandwich) enzyme-linked immunoassay (ELISA); however, covalent single-stranded DNA-streptavidi... |
12907740 | Dendrimeric coating of glass slides for sensitive DNA microarrays analysis. | Successful use and reliability of microarray technology is highly dependent on several factors, including surface chemistry parameters and accessibility of cDNA targets to the DNA probes fixed onto the surface. Here, we show that functionalisation of glass slides with homemade dendrimers allow production of more sensit... |
12907739 | Impact of surface chemistry and blocking strategies on DNA microarrays. | The surfaces and immobilization chemistries of DNA microarrays are the foundation for high quality gene expression data. Four surface modification chemistries, poly-L-lysine (PLL), 3-glycidoxypropyltrimethoxysilane (GPS), DAB-AM-poly(propyleminime hexadecaamine) dendrimer (DAB) and 3-aminopropyltrimethoxysilane (APS), ... |
12907706 | Repairing the Sickle Cell mutation. II. Effect of psoralen linker length on specificity of formation and yield of third strand-directed photoproducts with the mutant target sequence. | Three identical deoxyoligonucleotide third strands with a 3'-terminal psoralen moiety attached by linkers that differ in length (N = 16, 6 and 4 atoms) and structure were examined for their ability to form triplex-directed psoralen photoproducts with both the mutant T residue of the Sickle Cell beta-globin gene and the... |
12906914 | Simultaneous enantioselective separation of azelastine and three of its metabolites for the investigation of the enantiomeric metabolism in rats. I. Liquid chromatography-ionspray tandem mass spectrometry and electrokinetic capillary chromatography. | Enantioselective separation methods and the enantioselective determination of the anti-allergic drug azelastine and of three of its main phase I metabolites in a biological matrix underwent chromatographic and electrophoretic investigations. An enantioselective assay of a coupling of HPLC using a beta-cyclodextrin chir... |
12906909 | Enantiomeric separation of TAPP, H-Tyr-(D)Ala-Phe-Phe-NH(2), by capillary electrophoresis using 18-crown-6-tetracarboxylic acid as a chiral selector. | A capillary electrophoresis method for the enantiomeric separation of the tetrapeptide H-Tyr-(D)Ala-Phe-Phe-NH(2) (TAPP), has been developed and validated. The preferred background electrolyte (BGE) consisted of 0.1 M aqueous phosphoric acid adjusted to pH 3.0 with triethanolamine. The chiral selectors 18-crown-6-tetra... |
12904414 | Molecular cloning, expression, self-assembly, antigenicity, and seroepidemiology of a genogroup II norovirus isolated in France. | Virus-like particles of Dijon171/96 virus, a genogroup II norovirus, were expressed in a baculovirus system and were used for a seroepidemiological study of 1078 age-stratified human sera collected in Dijon, France. The results showed a seroprevalence of 74.1%. Furthermore, we showed that murine antibodies generated ag... |
12904050 | Multicomponent submicron features of biomolecules created by voltage controlled deposition from a nanopipet. | We have used a nanopipet as a nanopen to locally and controllably deposit complex biomolecules, including antibodies and DNA, onto a surface to create multicomponent and functional submicron features. Key advantages of this method are that the biomolecules are always in solution and the applied voltage provides fine co... |
12904044 | Photoinduced axial ligation and deligation dynamics of nonplanar nickel dodecaarylporphyrins. | The ground- and excited-state metal-ligand dynamics of nonplanar nickel(II) 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (NiDPP) and two fluorinated analogues (NiF(20)DPP and NiF(28)DPP) have been investigated using static and time-resolved absorption spectroscopy in toluene and in ligating media that differ in... |
12904039 | Ordered architectures of a soluble hexa-peri-hexabenzocoronene-pyrene dyad: thermotropic bulk properties and nanoscale phase segregation at surfaces. | An alkylated hexa-peri-hexabenzocoronene with a covalently tethered pyrene unit serves as a model to study self-assembling discotic pi-system dyads both in the bulk and at a surface. Wide-angle X-ray scattering, polarized light microscopy, and differential scanning calorimetry revealed bulk self-assembly into columnar ... |
12904037 | Self-assembly of ferrocene-functionalized perylene bisimide bridging ligands with PtII corner to electrochemically active molecular squares. | Ferrocenyl-substituted N,N'-di(4-pyridyl)perylene bisimide ligands have been synthesized by the coupling reaction of hydroxyphenoxy-perylene bisimides with ferrocenyl carboxylic acids. By means of metallosupramolecular self-assembly, hitherto unprecedented multiredox active dendritic molecular squares with 16 ferrocene... |
12904031 | Coordination-driven self-assembly of supramolecular cages: heteroatom-containing and complementary trigonal prisms. | The self-assembly of three nanoscopic prisms of approximate size 1 x 4 nm is reported. Tetrahedral carbon, silicon, and phosphorus were used as structure-defining elements in these coordination-based cages. A carbon-based assembly completes a pair of nanoscopic complementary 3-D structures. The formation of the structu... |
12904029 | Unprecedented monofunctional metalation of adenine nucleobase in guanine- and thymine-containing dinucleotide sequences by a cytotoxic platinum-acridine hybrid agent. | We have investigated the reactions of [PtCl(en)(ACRAMTU-S)](NO(3))(2) (2) (en = ethane-1,2-diamine; ACRAMTU = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea, acridinium cation, 1), the prototype of a new class of cytotoxic DNA-targeted agents, with 2'-deoxyguanosine (dGuo) and random-sequence native DNA by in-line... |
12904028 | pH as a trigger of peptide beta-sheet self-assembly and reversible switching between nematic and isotropic phases. | The hierarchical self-assembly of rationally designed synthetic peptides into beta-sheet tapes, ribbons, fibrils, and fibers opens up potentially useful routes to soft-solidlike materials such as hydrogels, organogels, or liquid crystals. Here, it is shown how incorporation of Glu (-CH(2)CH(2)COOH) or Orn (-CH(2)CH(2)C... |
12904012 | Enyne metathesis for the formation of macrocyclic 1,3-dienes. | Macrocyclic 1,3-dienes of a variety of ring sizes are formed in good yield via enyne metathesis. Both endo- and exo-products are observed depending on the size of the macrocycle. In general, 10-membered rings and smaller give exo-products, while 12-membered rings and larger give endo-products. The endo/exo selectivity ... |
12904011 | A designed beta-hairpin peptide for molecular recognition of ATP in water. | A designed 12-residue beta-hairpin peptide with a diagonal tryptophan (Trp) pair was shown to bind ATP in water through a combination of aromatic and electrostatic interactions. The affinity for ATP was 5800 M-1 (DeltaG approximately -5.0 kcal/mol), a remarkable affinity for a short, structured peptide in water, consis... |
12904002 | Ultrafast fluorescence investigation of excitation energy transfer in different dendritic core branched structures. | The mechanism of energy transport in branching structures is suggestively related to the geometry of the multichromophore architecture. In organic conjugated dendrimers, both incoherent (hopping) and coherent energy transfer processes have been observed from different dendritic architectures with different building blo... |
12903992 | Application of host-guest chemistry in nanotube-based device fabrication: photochemically controlled immobilization of azobenzene nanotubes on patterned alpha-CD monolayer/Au substrates via molecular recognition. | Azobenzene-functionalized nanotubes recognized and attached onto well-defined complementary regions of thiolated alpha-CD SAM/Au substrates via host-guest molecular recognition. The binding between the azobenzene nanotubes and the alpha-CD SAM/Au substrates was controlled by UV irradiation. The light-induced attachment... |
12903966 | Complexation of several fungicides with beta-cyclodextrin: determination of the association constants and isolation of the solid complexes. | The formation of inclusion complexes with beta-cyclodextrin was studied for several popular fungicides of different types: prochloraz, 2-phenylphenol, thiophanate methyl, 8-hydroxyquinoline, and benalaxyl. Phase solubility diagrams showed that in all cases complexation takes place, leading to an important increase of w... |
12737628 | The acetyltransferase 60 kDa trans-acting regulatory protein of HIV type 1-interacting protein (Tip60) interacts with the translocation E26 transforming-specific leukaemia gene (TEL) and functions as a transcriptional co-repressor. | The translocation E26 transforming-specific (ETS) leukaemia (TEL), alias the ETS variant (ETV6), gene is expressed in most human tissues and encodes a transcriptional repressor. The TEL gene is involved in more than 40 different chromosomal translocations associated with haematological malignancies. As little is known ... |
12733989 | Comparative membrane interaction study of viscotoxins A3, A2 and B from mistletoe (Viscum album) and connections with their structures. | Viscotoxins A2 (VA2) and B (VB) are, together with viscotoxin A3 (VA3), among the most abundant viscotoxin isoforms that occur in mistletoe-derived medicines used in anti-cancer therapy. Although these isoforms have a high degree of amino-acid-sequence similarity, they are strikingly different from each other in their ... |
12902465 | Mechanisms of ganglioside inhibition of APC function. | Gangliosides shed by tumor cells exert potent inhibitory effects on cellular immune responses. Here we have studied ganglioside inhibition of APC function. When human monocytes were preincubated in 50 micro M highly purified ganglioside G(D1a), pulsed with tetanus toxoid (TT), and washed, the expected Ag-induced prolif... |
12902281 | Directed evolution of Thermus maltogenic amylase toward enhanced thermal resistance. | The thermostability of maltogenic amylase from Thermus sp. strain IM6501 (ThMA) was improved greatly by random mutagenesis using DNA shuffling. Four rounds of DNA shuffling and subsequent recombination of the mutations produced the highly thermostable mutant enzyme ThMA-DM, which had a total of seven individual mutatio... |
12900287 | Synthesis of dendrimer-based biotin radiopharmaceuticals to enhance whole-body clearance. | To synthesize a biotin radiopharmaceutical that clears rapidly, dendrimer was used as a carrier and conjugated with succinimidyl 3-[(125)I]iodobenzoate and tetrafluorophenyl norbiotinamidosuccinate. Then, succinic anhydride was used to reduce its pI. In mice, the non-succinylated product showed high liver (67% ID/g) an... |
12899986 | Detection and characterization of cyclodextrin complexes with beta-carboline derivatives by spectroscopic techniques. | beta-Carboline alkaloids exhibit a great variety of pharmacological activities. The solid inclusion complexes of harmane and harmine with beta-cyclodextrin and also with hydroxypropyl-beta-cyclodextrin, have been prepared following different procedures. IR and NMR spectroscopies were employed to verify the interaction ... |
12899975 | Simultaneous high-throughput determination of clenbuterol, ambroxol and bromhexine in pharmaceutical formulations by HPLC with potentiometric detection. | Potentiometric detection of clenbuterol, ambroxol and bromhexine in marketed pharmaceuticals was described in six isocratic HPLC systems. The podant- and macrocyclic-type neutral ionophores, N,N,N',N'-tetracyclohexyl-oxybis(o-phenyleneoxy)diacetamide (TOPA) and hexakis(2,3,6-tri-O-octyl)-alpha-cyclodextrin (OCD), were ... |
12900393 | Vps27 recruits ESCRT machinery to endosomes during MVB sorting. | Down-regulation (degradation) of cell surface proteins within the lysosomal lumen depends on the function of the multivesicular body (MVB) sorting pathway. The function of this pathway requires the class E vacuolar protein sorting (Vps) proteins. Of the class E Vps proteins, both the ESCRT-I complex (composed of the cl... |
12900392 | Microtubules are the only structural constituent of the spindle apparatus required for induction of cell cleavage. | Structural constituents of the spindle apparatus essential for cleavage induction remain undefined. Findings from various cell types using different approaches suggest the importance of all structural constituents, including asters, the central spindle, and chromosomes. In this study, we systematically dissected the ro... |
12900889 | Study on thioridazine 5-sulfoxide epimerization and degradation by capillary electrophoresis. | We present a method for the stereoselective analysis of thioridazine 5-sulfoxide (THD 5-SO) in human plasma based on liquid-liquid extraction with diethyl ether and chiral resolution of the stereoisomers by capillary electrophoresis using hydroxypropyl-beta-cyclodextrin and sulfated beta-cyclodextrin as chiral selector... |
12900888 | Chiral separation of diastereomeric flavanone-7-O-glycosides in citrus by capillary electrophoresis. | The 2S- and 2R-diastereomers of major flavanone-7-O-glycosides found in sweet orange (Citrus sinensis), mandarine (Citrus deliciosa), grapefruit (Citrus paradisi), lemon (Citrus limon), and sour or bitter orange juice (Citrus aurantium) were separated for the first time by chiral capillary electrophoresis (CE) employin... |
12900885 | Enantiomeric separation of chiral peptide nucleic acid monomers by capillary electrophoresis with charged cyclodextrins. | Direct chiral separation of chiral peptide nucleic acid (PNA) monomers has been achieved for the first time by capillary electrophoresis (CE) with charged cyclodextrins as chiral selectors added to the electrophoretic buffer. Selectively modified 6-deoxy-6-N-histamino-beta-cyclodextrin and sulfobutyl ether-beta-CD were... |
12900884 | Separation of aminoalkanephosphonic acid enantiomers by indirect UV detection capillary electrophoresis with application of cyclodextrins. | Indirect UV detection capillary electrophoresis (CE) was used for the separation of aminoalkanephosphonic acid (AP) enantiomers by applying commercially available cyclodextrins as chiral discriminators. The results show that the separation of the enantiomers depends on pH of the background electrolyte, the molar ratio ... |
12900883 | Determination of L-hyoscyamine in atropine and D-hyoscyamine in L-hyoscyamine by chiral capillary electrophoresis as an alternative to polarimetry. | A method for the separation of atropine enantiomers, D- and L-hyoscyamine by capillary electrophoresis (CE) has been developed and validated. The advantages of the CE method compared with polarimetry include smaller amounts of analytes and a lower limit of detection of the unwanted enantiomer. Moreover, the present met... |
12900882 | Rapid determination of salbutamol in pharmaceutical preparations by chiral capillary electrophoresis. | A fast and simple method of chiral capillary electrophoresis (CE) has been applied to the analysis of salbutamol in different pharmaceutical preparations. Using of a 25 mM acetate buffer (pH 5.0), containing 13.1 mg/mL carboxymethyl-beta-cyclodextrin (CM-beta-CD), an applied voltage of 20 kV and a temperature of 25 deg... |
12900880 | Chiral characterization of deprenyl-N-oxide and other deprenyl metabolites by capillary electrophoresis using a dual cyclodextrin system in rat urine. | A chiral capillary electrophoresis method has been developed for the simultaneous separation of the enantiomers of deprenyl and eight of its metabolites, among them the recently described metabolite deprenyl-N-oxide. Although heptakis-(2,6-di-O-methyl)-beta-cyclodextrin (DIMEB) was suitable for the enantioresolution of... |
12900879 | Comparison of charged cyclodextrin derivatives for the chiral separation of atropisomeric polychlorinated biphenyls by capillary electrophoresis. | Charged cyclodextrin (CD) derivatives were used as chiral selectors in electrokinetic chromatography (EKC) for the chiral separation of highly hydrophobic neutral racemates such as atropisomeric polychlorinated biphenyls (PCBs). beta-CD-phosphated, beta-CD sulfated, succinylated-gamma-CD (Succ-gamma-CD) and succinylate... |
12900878 | Enantioseparation of dihydrofurocoumarin derivatives by various separation modes of capillary electrophoresis. | Chiral dihydrofurocoumarin compounds are currently the focus of industrial and pharmacological research. These derivatives have been shown to possess many physiological properties that could be medically beneficial. This work proposes four different chiral separation methods using capillary electrophoresis and micellar... |
12900877 | Simultaneous chiral discrimination of multiple profens by cyclodextrin-modified capillary electrophoresis in normal and reversed polarity modes. | Simultaneous enantioseparations of nine profens for their accurate chiral discrimination were achieved by capillary electrophoresis (CE) in the normal polarity (NP) mode with a single cyclodextrin (CD) system and in the reversed polarity (RP) mode with a dual CD system. The single CD system in the NP mode employed hept... |
12900876 | Infinite enantiomeric resolution of basic compounds using highly sulfated cyclodextrin as chiral selector in capillary electrophoresis. | Four chiral basic analytes, namely methadone, fluoxetine, venlafaxine, and tramadol, were selected as model compounds for investigating their stereoselective separation with highly sulfated gamma-cyclodextrin (HS gamma-CD) by capillary electrophoresis (CE)-UV and CE-mass spectrometry (MS). At high concentration of chir... |
12900875 | Quantitation of talinolol and other beta-blockers by capillary electrophoresis for in vitro drug absorption studies. | A capillary zone electrophoresis method is described for the enantioseparation of talinolol using heptakis(2,3-diacetyl-6-sulfo)-beta-cyclodextrin (HDAS-beta-CD) as a chiral selector. After liquid-liquid extraction of talinolol from physiological solution, electrokinetic injection was employed to improve the sensitivit... |
12900874 | Enantioseparation of warfarin and its metabolites by capillary zone electrophoresis. | A capillary zone electrophoresis (CZE) method with direct ultraviolet (UV)-absorbance detection is presented for the simultaneous enantiomeric separation of warfarin and its main metabolites, including warfarin alcohols, 4'-, 6-, and 7-hydroxywarfarin, using highly sulfated beta-cyclodextrin (HS-beta-CD) as the chiral ... |
12900873 | Enantiomeric separation of citalopram and its metabolites by capillary electrophoresis. | A simple and fast capillary electrophoretic method has been developed for the enantioselective separation of citalopram and its main metabolites, namely N-desmethylcitalopram and N,N-didesmethylcitalopram, using beta-cyclodextrin (beta-CD) sulfate as the chiral selector. For method optimisation several parameters were ... |
12900872 | Assessment of the stereoselective metabolism of methaqualone in man by capillary electrophoresis. | Methaqualone (MQ) and its hydroxylated metabolites are quinazoline derivatives that exhibit atropisomerism. As a continuation of our previous work with these compounds (Electrophoresis 2001, 22, 3270-3280), chiral capillary zone electrophoresis with hydroxypropyl-beta-cyclodextrin as buffer additive and multiwavelength... |
12900871 | Capillary electrophoresis evidence for the stereoselective metabolism of itraconazole in man. | Itraconazole (ITC) is a hydrophobic antimycotic drug with three chiral centers that is used clinically as a stereoisomeric mixture. A chiral capillary electrophoretic method for the separation of ITC stereoisomers and those of its main metabolite hydroxyitraconazole (HITC) was developed to determine the stereoselective... |
12900867 | Cyclodextrin-modified monolithic columns for resolving dansyl amino acid enantiomers and positional isomers by capillary electrochromatography. | We describe beta- and gamma-cyclodextrins (beta- and gamma-CD)-modified monolithic columns prepared by sol-gel process and chemical modifications. The monolithic silica column was fabricated inside a fused-silica capillary with 100 microm inner diameter by sol-gel process. The monolithic silica matrix was chemically mo... |
12900865 | Enantiomeric impurity profiling in ephedrine samples by enantioselective capillary electrochromatography. | This study reports on the development and preliminary validation of a capillary electrochromatographic (CEC) method for the enantioselective impurity profiling of D-ephedrine. As chiral selector a novel low-molecular-weight strong chiral cation exchanger, based on penicillamine sulfonic acid, immobilized on thiol-modif... |
12900864 | Separation of some chiral flavanones by micellar electrokinetic chromatography. | Micellar electrokinetic chromatography (MEKC) was applied for enantioseparation of selected flavanones, including naringin, hesperidin, neohesperidin, naringenin, hesperetin, pinostrobin, isosakuranetin, eriodictyol, and homoeriodictyol. gamma-Cyclodextrin (gamma-CD) and sodium cholate (SCh) were used as chiral modifie... |
12900863 | Polymeric alkenoxy amino acid surfactants: I. Highly selective class of molecular micelles for chiral separation of beta-blockers. | Two amino acid-based alkenoxy micelle polymers were synthesized for this study. These include polysodium N-undecenoxy carbonyl-L-leucinate (poly-L-SUCL) and polysodium N-undecenoxy carbonyl-L-isoleucinate (poly-L-SUCIL). The polymerization time and concentration of the synthesized micelle polymers were optimized by (1)... |
12900860 | Synthesis, analytical characterization and initial capillary electrophoretic use in acidic background electrolytes of a new, single-isomer chiral resolving agent: hexakis(2,3-di-O-acetyl-6-O-sulfo)-alpha-cyclodextrin. | The sodium salt of hexakis(2,3-di-O-acetyl-6-O-sulfo)-alpha-CD (HxDAS), the first member of the family of single-isomer, fully sulfated alpha-CDs, has been synthesized and used for the initial capillary electrophoretic separation of the enantiomers of nonionic, weak acid, weak base, and ampholytic analytes. HxDAS compl... |
12900856 | pH-dependent cyclodextrin capillary electrophoresis resolution of atropisomers. | Five noncommercial and four commercially available cyclodextrin (CD) derivatives were tested as chiral auxiliaries for the capillary electrophoretic (CE) resolution of racemic 1,1'-bi-(2-naphthol) (BN), 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BNHP), and 1,1'-binaphthyl-2,2'-diamine (BNA) at pH 4.0, 6.5, and 8.6. T... |
12900855 | Mechanistic study of the enantiomeric recognition of a basic compound with negatively charged single-isomer gamma-cyclodextrin derivatives using capillary electrophoresis, nuclear magnetic resonance spectroscopy, and infrared spectroscopy. | The possible mechanisms for the chiral recognition of 2-(R)-N-[1-(6-aminopyridin-2-ylmethyl)piperidin-4-yl]-2-[(1R)-3,3-difluorocyclopentyl]-2-hydroxy-2-phenylacetamide (RR-M3), and its enantiomer (SS-M3) with octakis(2,3-di-O-acetyl-6-sulfo)-gamma-cyclodextrin (ODAS-gamma-CD) and octakis(6-sulfo)-gamma-cycöpdextrom en... |
12900854 | Separation of basic drug enantiomers by capillary electrophoresis using chicken alpha1-acid glycoprotein: insight into chiral recognition mechanism. | Recombinant chicken alpha(1)-acid glycoprotein (alpha(1)-AGP) was prepared by the Escherichia coli expression system and completely deglycosylated alpha(1)-AGP (cd-alpha(1)-AGP) was obtained by treatments of native alpha(1)-AGP with a mixture of endoglycosidase and N-glycosidase. The average molecular masses of chicken... |
12897495 | Temperature and thermal dose distributions during intradiscal electrothermal therapy in the cadaveric lumbar spine. | <h4>Study design</h4>Human cadaveric lumbar spines were used to assess the temperature and thermal dose distribution during intradiscal electrothermal therapy in vitro.<h4>Objectives</h4>To determine whether intradiscal electrothermal therapy produces adequate tissue temperatures to denature annular collagen or ablate ... |
12895063 | A prototype calix[4]arene-based receptor for carbohydrate recognition containing peptide and phosphate binding groups. | A novel class of macrobicyclic receptors for carbohydrate recognition based on upper rim, peptide-bridged calix[4]arenes has been designed and synthesized. Receptor 12, in which a charged phosphate group cooperates with peptide hydrogen-bonding donor and acceptor groups in the binding process, is the most efficient and... |
12895048 | Acyclic congener of cucurbituril: synthesis and recognition properties. | The cucurbit[n]uril (CB[n]) family of macrocycles occupies a prominent role in molecular recognition and self-assembly studies despite the current inability to access specific cucurbit[n]uril homologues, derivatives, and analogues by straightforward tailor-made synthetic procedures. In this paper, we explore an approac... |
12895039 | Novel photoswitchable receptors: synthesis and cation-induced self-assembly into dimeric complexes leading to stereospecific [2+2]-photocycloaddition of styryl dyes containing a 15-crown-5 ether unit. | Styryl dyes 4a-e containing a 15-crown-5 ether unit and a quinoline residue with a sulfonatoalkyl or sulfonatobenzyl N-substituent were synthesized. The relationship between the photochemical behavior of these dyes and their aggregates derived from complexation with Mg(2+) in MeCN was studied using (1)H NMR and absorpt... |
12897209 | Increased T cell reactivity to amyloid beta protein in older humans and patients with Alzheimer disease. | Alzheimer disease (AD) is characterized by the progressive deposition of the 42-residue amyloid beta protein (Abeta) in brain regions serving memory and cognition. In animal models of AD, immunization with Abeta results in the clearance of Abeta deposits from the brain. However, a trial of vaccination with synthetic hu... |
12895120 | Metal binding characteristics of a laterally nonsymmetric aza cryptand upon functionalization with a pi-acceptor group. | The laterally nonsymmetric aza cryptand synthesized by condensing tris(2-aminoethyl)amine (tren) with tris[[2-(3-(oxomethyl)phenyl)oxy]ethyl]amine readily forms mononuclear inclusion complexes with both transition and main-group metal ions. In these complexes, the metal ion occupies the tren-end of the cavity making bo... |
12895115 | Stoichiometric and catalytic activation of the alpha- and beta-2,3,4-tri-O-acetyl-5-thioxylopyranosyl bromide inside the cavity of the Pd3(dppm)3(CO)2+ cluster. | The title cluster (Pd(3)(2+)) exhibits a pronounced affinity for Br(-) ions to form the very stable Pd(3)(Br)(+) adduct. Upon a 2-electron reduction, a dissociative process occurs generating Pd(3)(0) and eliminating Br(-) according to an ECE mechanism (electrochemical, chemical, electrochemical). At a lower temperature... |
12895104 | Formation of two diverse classes of poly(amino-alkoxide) chelates and their mononuclear and polynuclear lanthanide(III) complexes. | Factors that influence aggregation of lanthanide(III) (Ln(III)) ions to form polynuclear complexes were studied utilizing 1-aziridineethanol as a versatile source of macrocyclic and acyclic chelates. The facile ring-opening cyclo-oligomerization of 1-aziridineethanol leads to the formation of a series of polyaza cyclic... |
12895097 | Self-assembly of octarhenium-based neutral luminescent rectangular prisms. | Self-assembly of rhenium-based nanoscale rectangular prismatic boxes has been achieved in quantitative conversion. The fac-rhenium corner provided three mutually perpendicular coordination sites and served as a good candidate for the construction of 3-D boxes. These are the first Re-based, neutral, luminescent prisms o... |
12897056 | A conserved structural motif reveals the essential transcriptional repression function of Spen proteins and their role in developmental signaling. | Spen proteins regulate the expression of key transcriptional effectors in diverse signaling pathways. They are large proteins characterized by N-terminal RNA-binding motifs and a highly conserved C-terminal SPOC domain. The specific biological role of the SPOC domain (Spen paralog and ortholog C-terminal domain), and h... |
12898692 | Synthesis of a new potential tridentate anthracene ligand bearing deprotectable methoxymethoxy (OMOM) group at 1,8-positions: attempt to synthesize anionic hypervalent carbon compounds. | A novel potential tridentate ligand bearing deprotectable coordinating atoms, 1,8-bis(methoxymethoxy)-9-bromoanthracene (15), was synthesized. The key steps are as follows: 1) stepwise mono-oxygenation from 1,8-dibromo-9-methoxyanthracene by use of electrophilic oxaziridine and gaseous dioxygen, and 2) selective reduct... |
12898691 | Synthesis and reactivity of calix[4]arene-supported group 4 imido complexes. | New mononuclear titanium and zirconium imido complexes [M(NR)(R'(2)calix)] [M=Ti, R'=Me, R=tBu (1), R=2,6-C(6)H(3)Me(2) (2), R=2,6-C(6)H(3)iPr(2) (3), R=2,4,6-C(6)H(2)Me(3) (4); M=Ti, R'=Bz, R=tBu (5), R=2,6-C(6)H(3)Me(2) (6), R=2,6-C(6)H(3)iPr(2) (7); M=Zr, R'=Me, R=2,6-C(6)H(3)iPr(2) (8)] supported by 1,3-diorganyl e... |
12898682 | GdIII complexes with fast water exchange and high thermodynamic stability: potential building blocks for high-relaxivity MRI contrast agents. | On the basis of structural considerations in the inner sphere of nine-coordinate, monohydrated Gd(III) poly(aminocarboxylate) complexes, we succeeded in accelerating the water exchange by inducing steric compression around the water binding site. We modified the common DTPA(5-) ligand (DTPA=(diethylenetriamine-N,N,N',N... |
12898677 | The first successful crystallographic characterization of a cyclodextrin dimer: efficient synthesis and molecular geometry of a doubly sulfur-bridged beta-cyclodextrin. | Beta-cyclodextrin is transannularly disulfonylated at the 6(A)- and 6(B)-positions, and then converted to the corresponding 6(A),6(B)-diiodide and 6(A),6(B)-dithiol. Cross-coupling of the latter two species yields a single head-to-head-coupled beta-cyclodextrin dimer 5 with two sulfur linkers at adjacent 6-methylene ca... |
12898676 | Characteristics of organic transformations in a confined dendritic core: studies on the AIBN-initiated reaction of dendrimer cobalt(II) porphyrins with alkynes. | Cobalt(II) complexes of poly(aryl ester) dendrimer porphyrins [(m-[Gn]TPP)Co(II)] (generation number n=0-4), in the presence of azobisisobutyronitrile (AIBN) at 60 degrees C, underwent alkenylation with several alkynes at the metal center. A complete inhibition of double-bond migration (secondary transformation) was ob... |
12898675 | Synthesis and solid-state organization of coil-ring-coil block copolymers. | Shape-persistent macrocycles based on the phenyl-ethynyl-butadienyl backbone containing two extraannular hydroxyl groups were prepared by the oxidative coupling of the appropriate phenylethynyl oligomers. Carbodiimide-directed coupling with independently synthesized polystyrene carboxylic acid oligomers led to ABA coil... |
12898674 | From supramolecular block copolymers to advanced nano-objects. | The formation of asymmetric bis-complexes, based on terpyridine ligands and ruthenium ions, is described as a powerful tool for the self-assembly of polymer blocks end-functionalized with terpyridine units. This is illustrated in this contribution for the synthesis of amphiphilic metallo-supramolecular block copolymers... |
12872163 | Nucleation of apatite crystals in vitro by self-assembled dentin matrix protein 1. | Bones and teeth are biocomposites that require controlled mineral deposition during their self-assembly to form tissues with unique mechanical properties. Acidic extracellular matrix proteins play a pivotal role during biomineral formation. However, the mechanisms of protein-mediated mineral initiation are far from und... |
12892732 | Idiotype-anti-idiotype circuit in non-autoimmune mice after immunization with the epitope and complementary epitope 289-308aa of La/SSB: implications for the maintenance and perpetuation of the anti-La/SSB response. | <h4>Background</h4>Antibodies to La/SSB are usually found in sera of patients with Sjogren's Syndrome (SS) and Systemic Lupus Erythematosus (SLE). Recent work from our laboratory (Mol Med 2002;8:293-305) revealed that an active idiotypic network involving antibodies to epitopes of La/SSB and their anti-idiotypes exist ... |
12892942 | Inclusion complexation behavior of dyestuff guest molecules by a bridged bis(cyclomaltoheptaose)[bis(beta-cyclodextrin)] with a pyromellitic acid diamide tether. | A novel bridged bis(beta-cyclodextrin) with a pyromellitic acid 2,5-diamide tether (2) has been synthesized by reaction of 6(I)-(2-aminoethyleneamino)-6-deoxycyclomaltoheptaose [mono 6-(2-aminoethyleneamino)-6-deoxy-beta-cyclodextrin] with 1,2,4,5-benzenetetracarboxylic dianhydride. Its inclusion complexation behavior ... |
12893281 | Direct superoxide anion scavenging by a disodium disuccinate astaxanthin derivative: Relative efficacy of individual stereoisomers versus the statistical mixture of stereoisomers by electron paramagnetic resonance imaging. | Carotenoids are a related group of greater than 600 natural compounds, irrespective of geometric- and stereoisomers, with demonstrated antioxidant efficacy. The carotenoids are broadly divided into "carotenes," or non-oxygen substituted hydrocarbon carotenoids, and "xanthophylls," oxygen-substituted carotenoids. The na... |
12893291 | Novel inhibitor for prolyl aminopeptidase from Serratia marcescens and studies on the mechanism of substrate recognition of the enzyme using the inhibitor. | Prolyl aminopeptidase from Serratia marcescens hydrolyzed x-beta-naphthylamides (x=prolyl, alanyl, sarcosinyl, L-alpha-aminobutylyl, and norvalyl), which suggested that the enzyme has a pocket for a five-member ring. Based on the substrate specificity, novel inhibitors of Pro, Ala, and Sar having 2-tert-butyl-[1,3,4]ox... |
12889889 | Synthesis, structure, and chemical property of the first fluorine-containing porphycene. | [structure: see text] A pyrrolic macrocycle, beta-tetrakis(trifluoromethyl)porphycene, is the first example of a fluorine-containing porphycene. Four electron-withdrawing CF(3) substituents provide a highly distorted structure and an attractive electron-deficient nature for the porphycene framework. From the electroche... |
12889874 | Synthesis of muscothiazoles A and B: Critical role of methyl group substitution in RCM-based syntheses of macrocycles. | [reaction: see text] Muscothiazoles A (2b) and B (2c) have been prepared by two approaches that differ in the order of assembly of the rings. Comparative studies show that substitution of the carbon chains in substrate 5 or 12 (respective precursors to 13-membered and 14-membered rings by RCM), even by a single methyl ... |
12890607 | Engineering cyclodextrin glycosyltransferase into a starch hydrolase with a high exo-specificity. | Cyclodextrin glycosyltransferase (CGTase) enzymes from various bacteria catalyze the formation of cyclodextrins from starch. The Bacillus stearothermophilus maltogenic alpha-amylase (G2-amylase is structurally very similar to CGTases, but converts starch into maltose. Comparison of the three-dimensional structures reve... |
12889981 | Structure and phase transitions of alkyl chains on mica. | We use molecular dynamics as a tool to understand the structure and phase transitions [Osman, M. A.; et al. J. Phys. Chem. B 2000, 104, 4433-4439. Osman, M. A.; et al. J. Phys. Chem. B 2002, 106, 653-662] in alkylammonium micas. The consistent force field 91 is extended for accurate simulation of mica and related miner... |
12889966 | A heterocyclic peptide nanotube. | An open-ended hollow tubular structure is designed based on hydrogen-bond-directed self-assembly of a chimeric cyclic peptide subunit comprised of alternating alpha- and epsilon-amino acids. The design features a novel 1,4-disubstituted-1,2,3-triazole epsilon-amino acid and its utility as a peptide backbone substitute.... |
12889965 | First pseudorotaxane-like [3]complexes based on cryptands and paraquat: self-assembly and crystal structures. | A new cryptand, bis(1,3,5-phenylene)tri(1,4,7,10-tetraoxadecyl) (3a), has been synthesized in good yield from bis(5-hydroxy-1,3-phenylene)-26-crown-8 (2a) and tri(ethylene glycol) ditosylate using pseudo-high dilution conditions. 3a forms a strong 1:1 complex with paraquat (1) in acetone solution with a high apparent a... |
12889946 | Meta-conjugation and excited-state coupling in phenylacetylene dendrimers. | Traditional pictures of optical properties in phenylacetylene dendrimers view the molecule as a collection of independent chromophores, linked by meta-substitution at the central phenyl ring. While this picture is reasonable for explaining the observed absorption trends, it breaks down in describing the emission behavi... |
12889944 | Cucurbit[6]uril pseudorotaxanes: distinctive gas-phase dissociation and reactivity. | Cucurbit[6]uril forms a doubly charged complex with 1,4-butanediammonium cation that is observed using electrospray ionization Fourier transform mass spectrometry. Such 1:1 complexes are not observed for the smaller cucurbit[5]uril, which forms a 2:1 ammonium:cucurbituril complex instead. The 1:1 complex with cucurbit[... |
12889942 | Effect of catenation on protein folding stability. | Building on previous studies of the effects of covalent linking and backbone cyclization on protein folding stability, a theory is developed for the stabilization effect of catenating a dimeric protein. Relative to covalent linking, catenation is up to 1000-fold more powerful in stabilizing the folded structure. This d... |
12889938 | A cryptand/bisparaquat [3]pseudorotaxane by cooperative complexation. | The formation of the first cryptand/bisparaquat [3]pseudorotaxane appears to be highly cooperative. The apparent value of K2 is 17 times that of K1. |
12889932 | A cationic guest in a 24+ cationic host. | A new tetrahedral coordination cage M12L6 was prepared from a linear dipyrimidine ligand (L) and cis-protected palladium(II) (M). This cage showed unprecedented host-guest chemistry where the cationic host accommodated a cationic guest despite 24+ charges on the host framework. The unusual cation-cation host-guest chem... |
12885908 | Residues in the apical domain of the feline and canine transferrin receptors control host-specific binding and cell infection of canine and feline parvoviruses. | Canine parvovirus (CPV) and feline panleukopenia virus (FPV) capsids bind to the transferrin receptors (TfRs) of their hosts and use these receptors to infect cells. The binding is partially host specific, as FPV binds only to the feline TfR, while CPV binds to both the canine and feline TfRs. The host-specific binding... |
12885907 | Cell cycle arrest by Kaposi's sarcoma-associated herpesvirus replication-associated protein is mediated at both the transcriptional and posttranslational levels by binding to CCAAT/enhancer-binding protein alpha and p21(CIP-1). | Lytic-cycle replication of Kaposi's sarcoma-associated herpesvirus (KSHV) in PEL cells causes G(1) cell cycle arrest mediated by the virus-encoded replication-associated protein (RAP) (or K8 protein), which induces high-level expression of the cellular C/EBPalpha and p21 proteins. Here we have examined the mechanism of... |
12885906 | Endocytosis of hepatitis B immune globulin into hepatocytes inhibits the secretion of hepatitis B virus surface antigen and virions. | Hepatitis B immunoglobulin is used for prophylaxis against hepatitis B virus (HBV) and is thought to act by neutralization of virions and hepatitis B virus surface antigen (HBsAg)-containing particles in circulation. Using a panel of hepatocyte-derived cell lines, the present study investigated in vitro whether HBs-spe... |
12885889 | Oral immunogenicity of human papillomavirus-like particles expressed in potato. | Human papillomavirus-like particles (HPV VLPs) have shown considerable promise as a parenteral vaccine for the prevention of cervical cancer and its precursor lesions. Parenteral vaccines are expensive to produce and deliver, however, and therefore are not optimal for use in resource-poor settings, where most cervical ... |
12885544 | Measuring the swelling behavior of polymer microspheres with different cross-linking densities and the medium-dependent color changes of the resulting latex crystal films. | We measured the size changes of cross-linked polymer microspheres of narrow size distribution with different cross-linking densities by the in situ swelling method. The swelling behavior of these cross-linked polymer microspheres revealed that their maximal swelling degree linearly decreased as a function of the cross-... |
12885669 | Small angle X-ray scattering study of meso-tetrakis (4-sulfonatophenyl) porphyrin in aqueous solution: a self-aggregation model. | The aggregate morphology of meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS(4)) in aqueous solution is investigated by using small angle x-ray scattering (SAXS) technique. Measurements were performed at pH 4.0 and 9.0 to monitor the pH influence on the structural parameters of the aggregates. Radii of gyration were ob... |
12885668 | Effects of a carane derivative local anesthetic on a phospholipid bilayer studied by molecular dynamics simulation. | Molecular dynamics (MD) simulations of two hydrated palmitoyloleoylphosphatidylcholine (POPC) bilayers each containing eight carane derivative (KP-23) local anesthetic (LA) molecules in neutral (POPC-LA) or protonated (POPC-LAH) forms were carried out to investigate the effect of KP-23 and its protonation on the bilaye... |
12885667 | Atomic force microscopy and light scattering of small unilamellar actin-containing liposomes. | Three-dimensional networks of filamentous actin (F-actin) encapsulated inside phosphatidylcholine liposomes are currently being used in an effort to model the cytoskeleton and plasma membrane of eukaryotic cells. In this article, unilamellar lipid vesicles consisting of egg yolk-derived phosphatidylcholine encapsulatin... |
12885666 | The shape parameter of liposomes and DNA-lipid complexes determined by viscometry utilizing small sample volumes. | A minicapillary viscometer utilizing <0.5 ml of sample at a volume fraction of <0.1% is described. The calculated a/b of DPPC/DPPG multilamellar liposome was 1.14 as prolate ellipsoids and a/b of dioleoylpropyltrimethyl ammonium methylsulfate-DNA complex at a charge ratio of 4:1 (+/-) was 3.7 as prolate ellipsoids or 4... |
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