id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
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12122991 | Synthesis of mixed heterocalixarenes from benzofuranyl methanols and activated indoles. | Mixed heterocalix[3]arenes and heterocalix[4]arenes containing indole and benzofuran rings can be synthesised via acid-catalysed reactions of benzofuranyl methanols and activated indoles: these new calixarene types are of interest as potential molecular receptors. |
12122989 | Langmuir and Langmuir-Blodgett films of a novel tryptophan peptide lipid. | A novel tryptophan peptide lipid, C18H35O (SA)-Gly-Trp-Gly-OH, was synthesized and studied for its surface chemistry and spectroscopic properties. |
12119723 | The fixation of linear versus loop-type peptidic structures by metal coordination: the coordination chemistry of Val-Val- and Val-Val-Val-bridged dicatechol ligands. | The Val-Val-bridged dicatechol ligand L1-H4 forms triplybridged dinuclear complexes with titanium(IV) ions, while the more flexible Val-Val-Val derivative L2-H4 leads to mixtures of complexes containing species with a cyclic arrangement of the ligand; with [cis-MoO2]2+ on the other hand, a well-defined macrocycle [(L2)... |
12119699 | Minimalist peptidomimetic cyclophanes as strong organogelators. | L-Valine containing cyclophanes have been shown to gelate organic solvents leading to soft materials with a clear expression of their chirality at the supramolecular level. |
12119695 | The first successful investigation into a cyclodextrin-based enzyme model as an efficient catalyst for luminol chemiluminescent reaction. | The chemiluminescence of the luminol-H2O2 system is found for the first time to be remarkably enhanced by the Ce(IV) complexes of cyclodextrin dimers. |
12119682 | Second sphere supramolecular chirality: racemic hybrid H-bonded 2-D molecular networks. | Neutral hybrid 2-D networks have been generated using a bis-amidinium capable of chelating M(CN)6(3-) anions via hydrogen bonds: the packing of the achiral 2-D networks leads to channels which are occupied by water molecules forming polymeric H-bonded chains; furthermore, owing to the dihapto mode of H-bonding, the pre... |
12119679 | A new supramolecular isomer of [Zn(nicotinate)2]n: a novel 4(2).8(4) network that is the result of self-assembly of 4-connected nodes. | Self-assembly of Zn(NO3)2 with m-pyridinecarboxylate (nicotinate) under mild conditions affords several products including a novel three-dimensional network [Zn(nicotinate)2]n that has connectivity defined by the circuit symbol 4(2).8(4). |
12090738 | MitoExtra SuperGen. | SuperGen Inc is developing a cyclodextrin-based reformulation of mitomycin C (MitoExtra) for the potential treatment of gastic, pancreatic, breast lung and colorectal cancers. In April 2002, the NDA was pending approval from the US FDA after a March 2002 filing of a final response including data from a phase II trial [... |
12068755 | [Glomerular morphologic protection after acute ischemia through the administration of Surgiran: (PGE1 and Alfadex, glucose cyclic oligomer). Morphometric study]. | <h4>Objective</h4>To quantify the morphologic protection of PGE1 on renal glomerulus following normothermic acute renal ischemia.<h4>Methods</h4>This experimental study was carried out in 48 adult male Wistar rats. A simple right nephrectomy was performed in all rats. The rats were divided into two groups: one group wa... |
12061559 | Chiral separation of amino acids derivatized with fluoresceine-5isothiocyanate by capillary electrophoresis and laser-induced fluorescence detection using mixed selectors of beta-cyclodextrin and sodium taurocholate. | Chiral separation of 20 pairs of amino acids derivatized with fluoresceine-5-isothiocyanate (FITC) by capillary electrophoresis and laser-induced fluorescence detection was studied using the mixture of beta-cyclodextrin (beta-CD) and sodium taurocholate (STC) as selector. Resolution was considerably superior to that ob... |
12061558 | New triazine spectroscopic reagent for the separation of DL-amino acids by micellar electrokinetic chromatography. | An approach to the chiral separation of racemic mixtures of amino acids by means of micellar electrokinetic chromatography after derivatization with a new triazine spectroscopic reagent, 3-(4,6-dichloro-1,3,5-triazinylamino)-7-dimethylamino-2-methylphenazine (DTDP), has been evaluated. It was found that the derivatives... |
12061564 | Chromatographic behaviour of selected steroids and their inclusion complexes with beta-cyclodextrin on octadecylsilica stationary phases with different carbon loads. | Retention and separation studies of selected estrogens, progestogens and their inclusion complexes with beta-cyclodextrin were conducted using two C18 HPLC columns with different carbon loads. The difference in carbon load between investigated octadecylsilica packing materials was about 50%. The mobile phases were comp... |
12058960 | Neutrophil hypochlorous acid production is impaired in multiple organ failure patients with candidaemia; reversal with antifungal agents. | <h4>Objective and design</h4>Neutrophil-derived hypochlorous acid (PMN-HOCL) is a potent bactericidal and fungicidal agent. Neutrophils from patients with multiple organ failure (MOF) have an altered ability to inhibit Candida albicans. Conversely antifungal agents are effective in decreasing mortality in MOF patients ... |
12058940 | Continuous fractionation of enantiomer pairs in free solution using an electrophoretic analog of simulated moving bed chromatography. | Continuous fractionation of the left and right enantiomers of Piperoxan was performed in free solution in a vortex-stabilized electrophoresis apparatus. Sulfated beta-cyclodextrin was used as the chiral selector. A capillary electrophoresis (CE) study of the separation of Piperoxan enantiomers was carried out in order ... |
12054771 | Abeta42-peptide assembly on lipid bilayers. | One of the major pathological features of Alzheimer's disease (AD) is the presence of extracellular amyloid plaques that are composed predominantly of the amyloid-beta peptide (Abeta). Diffuse plaques associated with AD are composed predominantly of Abeta42, whereas senile plaques contain both Abeta40 and Abeta42. Rece... |
12054557 | A two step model aimed at delivering antisense oligonucleotides in targeted cells. | To be efficient in vivo antisense oligonucleotides must reach the targeted cells and then cross the cellular membrane. We propose a two step system where the oligonucleotide is first electrostatically bound to a peptide coupled to a ligand of a cellular receptor. A complex is formed which allows the oligonucleotide to ... |
12051850 | Crystal structures and structural comparison of Thermoactinomyces vulgaris R-47 alpha-amylase 1 (TVAI) at 1.6 A resolution and alpha-amylase 2 (TVAII) at 2.3 A resolution. | The X-ray crystal structures of Thermoactinomyces vulgaris R-47 alpha-amylase 1 (TVAI) and alpha-amylase 2 (TVAII) have been determined at 1.6 A and 2.3 A resolution, respectively. The structures of TVAI and TVAII have been refined, R-factor of 0.182 (R(free)=0.206) and 0.179 (0.224), respectively, with good chemical g... |
12044033 | Towards optimal design of second-generation immunomodulatory oligonucleotides. | The goal of using of oligodeoxyribonucleotides containing CpG dinucleotides (CpG DNA) as immunomodulatory agents has been realized in recent years. Therapeutic applications of CpG DNA as monotherapies and as adjuvants in combination with vaccines, antibodies, antigens and allergens for a number of disease indications a... |
12038998 | Starch-hydrolyzing enzymes from thermophilic archaea and bacteria. | Extremophlic microorganisms have developed a variety of molecular strategies in order to survive in harsh conditions. For the utilization of natural polymeric substrates such as starch, a number of extremophiles, belonging to different taxonomic groups, produce amylolytic enzymes. This class of enzyme is important not ... |
12033256 | A method for the analysis of low-mass molecules by MALDI-TOF mass spectrometry. | We report a novel method termed matrix suppressed laser desorption/ionization to improve the analysis of low-mass molecules by MALDI-TOF mass spectrometry. In this method, the surfactant of cetrimonium bromide (CTAB) is added to the conventional matrix of alpha-cyano-4-hydroxycinnamic acid solution to prepare the MALDI... |
11981861 | Chiral capillary electrophoretic determination of the enantiomeric purity of tetrahydronaphthalenic derivatives, melatoninergic ligands, using highly sulfated beta-cyclodextrins. | Using cyclodextrin capillary zone electrophoresis (CD-CZE), baseline separation of synthetic tetrahydronaphthalenic derivatives, potential melatoninergic compounds, was achieved. A method for the enantioresolution of these tetralins and determination of their enantiomeric purity was developed using anionic CDs (highly ... |
11981860 | A silica monolithic column prepared by the sol-gel process for enantiomeric separation by capillary electrochromatography. | A method for the preparation of a silica monolithic capillary electrochromatography (CEC) column for the separation of enantiomers has been developed. The porous silica monolith was fabricated inside a fused-silica capillary column by using the sol-gel process. After gelation for 24 h, hydrothermal treatment at 100 deg... |
11981852 | Separation and first structure elucidation of Cremophor EL-components by hyphenated capillary electrophoresis and delayed extraction-matrix assisted laser desorption/ionization-time of flight-mass spectrometry. | The polyethoxylated heterogeneous components of the so far poorly characterized nonionic emulsifier Cremophor EL (polyoxyl 35 castor oil) (CrEL) were fractionated by cyclodextrin-modified micellar electrokinetic capillary chromatography (CD-MEKC). Due to the low UV absorbance of most of the CrEL-components an indirect ... |
12023822 | Substrate channelling in 2-oxo acid dehydrogenase multienzyme complexes. | Heteronuclear NMR spectroscopy and other experiments indicate that the true substrate of the E1 component of 2-oxo acid dehydrogenase complexes is not lipoic acid but the lipoyl domain of the E2 component. E1 can recognize the lipoyl-lysine residue as such, but reductive acylation ensues only if the domain to which the... |
12022646 | Separation of ionic liquid cations and related imidazole derivatives by alpha-cyclodextrin modified capillary zone electrophoresis. | The separation and detection of 1-alkyl-3-methylimidazolium, including isomers, and related imidazole derivatives was performed by alpha-cyclodextrin (alpha-CD) modified capillary zone electrophoresis. The separations were carried out in a running buffer comprising 5.0 mM triethylamine and 2.0 mM alpha-CD adjusted to p... |
12022471 | Metallothionein: the multipurpose protein. | Metallothioneins (MTs) are intracellular, low molecular, low molecular weight, cysteine-rich proteins. Ubiquitous in eukaryotes, MTs have unique structural characteristics to give potent metal-binding and redox capabilities. A primary role has not been identified, and remains elusive, as further functions continue to b... |
12022470 | Signalling in viral entry. | Viral infections are serious battles between pathogens and hosts. They can result in cell death, elimination of the virus or latent infection keeping both cells and pathogens alive. The outcome of an infection is often determined by cell signalling. Viruses deliver genomes and proteins with signalling potential into ta... |
12017396 | A randomized, double-blind, multicenter trial of nimesulide-beta-cyclodextrin versus naproxen in patients with osteoarthritis. | <h4>Background</h4>Nonsteroidal anti-inflammatory drugs are the most widely used agents in the symptomatic treatment of osteoarthritis (OA). No data are presently available on the medium-term management of this disease with an on-demand treatment regimen, which nevertheless reflects medical practice.<h4>Objectives</h4>... |
12013232 | Development of comparative methods using gas chromatography-mass spectrometry and capillary electrophoresis for determination of endocrine disrupting chemicals in bio-solids. | Two analytical separation techniques are being investigated for their potential in determining a wide range of endocrine disrupting chemicals (EDCs) in the environment. Capillary electrophoresis (CE) in the micellar mode in conjunction with a cyclodextrin (CD) modifier is shown to have potential for determination of al... |
12004356 | Vimentin, smooth muscle actin, desmin, S-100 protein, p53, and estrogen receptor expression in elastofibroma and nodular fasciitis. | Elastofibroma and nodular fasciitis are two rare, benign soft tissue tumors. Elastofibroma is suggested to develop as a result of abnormal degeneration of elastic fibers after local trauma. Similarly, fibroblastic proliferation, which is triggered by local trauma or nonspecific inflammatory event, is suggested to play ... |
11998447 | Dendrimer grafts for delivery of 5-fluorouracil. | Polyamidoamine (PAMAM) dendrimers were prepared by linking methyl methacrylate and ethylenediamine successively on an amine core. Surface modification of PAMAM dendrimer was done by fatty acid grafting converting them to a unimolecular micellar system (Dendrimer grafts). IR, 1H NMR, 13C NMR studies confirmed the struct... |
11999523 | Photochemical ion receptor based on a structurally distorted ruthenium(II) complex having a crown-ether moiety at the 3,3'-positions on the 2,2'-bipyridine ligand. | Ru(bpy)2(CE-bpy)2+ was prepared where bpy and CE-bpy were 2,2'-bipyridine and bpy having a crown-ether moiety at the 3,3'-positions, respectively. Although Ru(bpy)2(CE-bpy)2+ showed only very weak emission in acetonitrile, recognition of Na+, Li+, or K+ by the crown-ether moiety in CE-bpy resulted in increases in both ... |
11999125 | Development of a lyophilised RH1 formulation: a novel DT diaphorase activated alkylating agent. | RH1 is a novel aziridinylbenzoquinone alkylating agent, which is activated in tumour cells by DT diaphorase. In common with previous aziridinylbenzoquinones, RH1 exhibits limited aqueous stability and solubility. The aim of this study was to examine the pharmaceutical properties of RH1 with a view to preparing a suitab... |
11999124 | Calorimetric studies of diclofenac sodium in aqueous solution of cyclodextrin and water-ethanol mixtures. | The technique of solution calorimetry has been employed to study the interaction between diclofenac sodium and beta-cyclodextrin by determining the enthalpies of solution of the drug in water and in aqueous beta-cyclodextrin solution. Thermodynamic parameters characterizing the binding process such as enthalpy deltaH0,... |
11996838 | NMR diffusion as a novel tool for measuring the association constant between cyclodextrin and guest molecules. | In this paper we introduce the use of diffusion measurements by nuclear magnetic resonance (NMR) spectroscopy for determining association constants of weak and very weak interactions between cyclodextrin and guest molecules, as long as both the free and complexed guest molecules are soluble to an extent that allows goo... |
11991589 | Incidence of regeneration of the chorda tympani nerve after middle ear surgery. | We retrospectively reviewed 52 patients who underwent middle ear surgery during which the chorda tympani nerves were severed and who then underwent secondary surgery 1 to 5 years later. In 22 patients (42.3%), regenerated chorda tympani nerves (entire length of the tympanic segment) were detected in the submucosal laye... |
11991532 | Determination of MDMA and its metabolites in blood and urine by gas chromatography-mass spectrometry and analysis of enantiomers by capillary electrophoresis. | A gas chromatography-mass spectrometry (GC-MS) method was used for the simultaneous quantitation of 3,4-methylenedioxymethamphetamine (MDMA) and the 3,4-methylenedioxyamphetamine (MDA), 4-hydroxy-3-methoxymethamphetamine (HMMA), and 4-hydroxy-3-methoxyamphetamine (HMA) metabolites in plasma and urine samples after the ... |
11988856 | The effects of higenamine on LPS-induced experimental disseminated intravascular coagulation (DIC) in rats. | The effect of higenamine, a benzyl-tetrahydroisoquinoline alkaloid of the roots of Aconitum spp. (Ranunculaceae), on disseminated intravascular coagulation (DIC), was investigated using an experimental DIC rat model. The oral administration of higenamine (10 mg/kg or 50 mg/kg), significantly ameliorated the decrease of... |
11983926 | SOFTDOCK: understanding of molecular recognition through a systematic docking study. | Molecular recognition and docking are essential to the biological functions of proteins. SOFTDOCK was one of the first molecular docking methods developed for protein-protein docking. Its ability to represent the molecular surface with different shapes and properties and to dock a variety of molecular complexes with ce... |
11983924 | Combining constitutive materials modeling with atomic force microscopy to understand the mechanical properties of living cells. | The goal of this work is to study the properties of living cells and cell membranes by using atomic force microscopy. During atomic force microscopy (AFM) measurement, there is a strong mechanical coupling between the AFM tip and the cell. The purpose of this paper is to present a model of the overall mechanical respon... |
11983419 | Upward shift of the pH optimum of Acremonium ascorbate oxidase. | A gene encoding a thermostable Acremonium ascorbate oxidase (ASOM) was randomly mutated to generate mutant enzymes with altered pH optima. One of the mutants, which exhibited a significantly higher activity in the pH range 4.5-7 compared to ASOM, had a Gln183Arg substitution in the region corresponding to SBR1, one of ... |
11971789 | Metallosupramolecular coordination polyelectrolytes: potential building blocks for molecular-based devices. | Metal-ion-induced self-assembly of ditopic ligands, based on bisterpyridines, and transition metal ions result in formation of metallosupramolecular coordination polyelectrolytes (MEPE). The positive charge of MEPE can be utilized in several ways to process highly ordered architectures. Alternating adsorption of MEPE a... |
11960492 | Cyclodextrin-derived host molecules as reversal agents for the neuromuscular blocker rocuronium bromide: synthesis and structure-activity relationships. | A series of mono- and per-6-substituted cyclodextrin derivatives were synthesized as synthetic receptors (or host molecules) of rocuronium bromide, the most widely used neuromuscular blocker in anaesthesia. By forming host-guest complexes with rocuronium, these cyclodextrin derivatives reverse the muscle relaxation ind... |
11960477 | Hydronium ion complex of 18-crown-6: where are the protons? A density functional study of static and dynamic properties. | A quantum-chemical study employing the BLYP density functional is reported for the complex of H3O+ with 18-crown-6. According to a Car-Parrinello molecular dynamics (CPMD) study at 340 K, the complex is quite flexible, and is characterized by three quasi-linear (two-center) hydrogen-bond interactions for most of the ti... |
11960464 | Long-range electron transfer in porphyrin-containing [2]-rotaxanes: tuning the rate by metal cation coordination. | A series of [2]-rotaxanes has been synthesized in which two Zn(II)-porphyrins (ZnP) electron donors were attached as stoppers on the rod. A macrocycle attached to a Au(III)-porphyrin (AuP+) acceptor was threaded on the rod. By selective excitation of either porphyrin, we could induce an electron transfer from the ZnP t... |
11960459 | Extreme electronic modulation of the cofacial porphyrin structural motif. | The synthesis, electrochemistry, and optical spectroscopy of an extensive series of cofacial bis[(porphinato)zinc(II)] compounds are reported. These species were synthesized using sequential palladium-catalyzed cross-coupling and cobalt-mediated [2+2+2] cycloaddition reactions. This modular methodology enables facile c... |
11960422 | Reversing a rotaxane recognition motif: threading oligoethylene glycol derivatives through a dicationic cyclophane. | An already well-established recognition motif-namely one in which the NH2+ centers in the rod sections of the dumbbell components of rotaxanes are encircled by macrocyclic polyether components-has been turned simultaneously outside-in and inside-out, a fact that has been proved beyond any doubt by the stoppering of bot... |
11959967 | Iron uptake in ferritin is blocked by binding of [Cr(TREN)(H(2)O)(OH)](2+), a slow dissociating model for [Fe(H(2)O)(6)](2+). | Ferritin concentrates iron as a hydrous ferric oxide in a protein cavity (8 nm in diameter) by using eight pores along the threefold symmetry axes of the octahedral supramolecular structure. The role of ligand exchange in the entry of Fe(II) hexahydrate into ferritin protein has been studied with [Cr(TREN)(H(2)O)(OH)](... |
11959966 | Shape-selective transport through rectangle-based molecular materials: thin-film scanning electrochemical microscopy studies. | Microporous thin films (approximately equal to 50 to 400 nm) composed of discrete, cavity-containing molecular rectangles have been prepared. The films, which contain both amorphous and microcrystalline domains, display shape-selective transport behavior. They are permeable to small molecules and to molecules that are ... |
11959965 | Positioning protein molecules on surfaces: a nanoengineering approach to supramolecular chemistry. | We discuss a nanoengineering approach for supramolecular chemistry and self assembly. The collective properties and biofunctionalities of molecular ensembles depend not only on individual molecular building blocks but also on organization at the molecular or nanoscopic level. Complementary to "bottom-up" approaches, wh... |
11959964 | Investigation of the role of ansocalcin in the biomineralization in goose eggshell matrix. | The role of proteins in biomineralization and the mechanism of eggshell formation are not well understood. We have isolated and purified the major protein, ansocalcin from goose eggshell matrix. The amino acid sequence study indicates that ansocalcin is homologous to the chicken eggshell protein, ovocleidin 17, and C-t... |
11959963 | Noncovalent self-assembly of a heterotetrameric diiron protein. | Diiron and dimanganese proteins catalyze a wide range of hydrolytic and oxygen-dependent reactions. To probe the mechanisms by which individual members of this class of proteins are able to catalyze such a wide range of reactions, we have prepared a model four-helix bundle with a diiron site located near the center of ... |
11959962 | Fibronectin extension and unfolding within cell matrix fibrils controlled by cytoskeletal tension. | Evidence is emerging that mechanical stretching can alter the functional states of proteins. Fibronectin (Fn) is a large, extracellular matrix protein that is assembled by cells into elastic fibrils and subjected to contractile forces. Assembly into fibrils coincides with expression of biological recognition sites that... |
11959961 | De novo design of biomimetic antimicrobial polymers. | The design of polymers and oligomers that mimic the complex structures and remarkable biological properties of proteins is an important endeavor with both fundamental and practical implications. Recently, a number of nonnatural peptides with designed sequences have been elaborated to provide biologically active structu... |
11959960 | Modulation of protein-protein interactions by synthetic receptors: design of molecules that disrupt serine protease-proteinaceous inhibitor interaction. | In the present article we describe the design and evaluation of a synthetic receptor that binds to the exterior surface of chymotrypsin and disrupts its interaction with proteinaceous inhibitors, such as soybean trypsin inhibitor, basic pancreatic trypsin inhibitor, ovomucoid turkey inhibitor, and Bowman-Birk inhibitor... |
11959959 | Plastic- and liquid-crystalline architectures from dendritic receptor molecules. | Host molecules with U-shaped receptor cavities have been derivatized at their convex side with two n-hydrocarbon tails (1), two first-generation (2), and two second-generation (3) monodendritic hydrocarbon tails. Although hosts 1 and 2 display plastic-crystalline behavior, evidence suggests that host 3 forms a cubic li... |
11959958 | Supramolecular self-assembled fullerene nanostructures. | Four ionic fullerene derivatives, which are relatively soluble in polar solvents, are shown to organize into morphologically different nanoscale structures. Spheres, nanorods, and nanotubules form in water depending on the side chain appendage of the fullerene spheroid. Images at different nanoscale structures were obt... |
11959957 | Intramolecular DNA coiling mediated by metallo-supramolecular cylinders: differential binding of P and M helical enantiomers. | We have designed a synthetic tetracationic metallo-supramolecular cylinder that targets the major groove of DNA with a binding constant in excess of 10(7) M(-1) and induces DNA bending and intramolecular coiling. The two enantiomers of the helical molecule bind differently to DNA and have different structural effects. ... |
11959956 | Selective immobilization of proteins to self-assembled monolayers presenting active site-directed capture ligands. | This paper describes a method for the selective and covalent immobilization of proteins to surfaces with control over the density and orientation of the protein. The strategy is based on binding of the serine esterase cutinase to a self-assembled monolayer presenting a phosphonate ligand and the subsequent displacement... |
11959955 | Metal ion recognition and molecular templating in self-assembled monolayers of cyclic and acyclic polyethers. | Our recent work with cyclic and acyclic polyether self-assembled monolayers (SAMs) on gold is presented. A series of dithia-crown-tetrathiafulvalene derivatives with one or two disulfide groups has been prepared, and their SAMs on gold have been characterized by electrochemistry and by reflection-absorption infrared sp... |
11959954 | Colloidal assemblies on patterned silane layers. | The site-selective assembly of colloidal polymer particles onto laterally patterned silane layers was studied as a model system for the object assembly process at mesoscale dimensions. The structured silane monolayers on silicon oxide substrates were fabricated by a combination of liquid- and gas-phase deposition of di... |
11959953 | Formation of oriented molecular nanowires on mica surface. | Molecular "nanowire" structures composed of the charge transfer complex of a bis-tetrathiafulvalene substituted macrocycle and tetrafluorotetracyanoquinodimethane were constructed on mica substrates by employing the Langmuir-Blodgett technique. The nanowires transferred from a dilute aqueous potassium chloride subphase... |
11959952 | Self-assembly of a metal-ion-bound monolayer of trigonal connectors on mercury: an electrochemical Langmuir trough. | The adsorption of the trigonal connector, 1,3,5-tris[10-(3-ethylthiopropyl)dimethylsilyl-1,10-dicarba-closo-decaboran-1-yl]benzene (1), from acetonitrile/0.1 M LiClO(4) on the surface of mercury at potentials ranging from +0.3 to -1.4 V (vs. aqueous Ag/AgCl/1 M LiCl) was examined by voltammetry, Langmuir isotherms at c... |
11959951 | A self-assembled, redox-responsive receptor for the selective extraction of LiCl from water. | There is considerable interest in synthetic ionophores with high affinity and selectivity for Li(+). But so far, compounds that selectively bind Li(+) in the presence of other alkali and alkaline earth metal ions are rare and current approaches toward this goal are often accompanied with substantial synthetic efforts. ... |
11959950 | Hydrogen bond-directed aggregation of diazadibenzoperylene dyes in low-polarity solvents and the solid state. | The formation of complex superstructures via hydrogen bonding of two ditopic building blocks, diazadibenzoperylenes 1a,b and isophthalic acid 2, has been investigated. It was found that only the phenoxy-substituted diazadibenzoperylene 1a forms extended assemblies with 2 in complexes of a 1:1 stoichiometry, whereas for... |
11959949 | Circular dichroism readout of sugar recognition in the cleft of a fused-pyridine receptor. | Dicarboxamide host 2 forms 1:1 complexes with n-octyl pyranosides derived from D-glucose, D-mannose, D-galactose, D-fucose, D-lyxose, and D-arabinose. Association constants (K(a)) in the range of 77-940 M(-1) were measured in chloroform by means of induced circular dichroism and fluorescence spectroscopy. Variations in... |
11959948 | From reactants to products via simple hydrogen-bonding networks: Information transmission in chemical reactions. | The transmission of information is ubiquitous in nature and often occurs through supramolecular hydrogen bonding processes. Here we report that there is a remarkable correlation during synthesis between the efficiency of the hydrogen-bond-directed assembly of peptide-based [2]rotaxanes and the symmetry distortion of th... |
11959947 | Resorcinarenes with 2-benzimidazolone bridges: self-aggregation, self-assembled dimeric capsules, and guest encapsulation. | The synthesis and spectroscopic characterization of self-assembled dimeric resorcinarenes 1a-d containing four 2-benzimidazolone (cyclic urea) bridges are reported. The nanometer-size capsules are held together by a cyclic array of complementary hydrogen bonds. Unlike the related imide-bridged resorcinarenes reported b... |
11959946 | Hydrogen bonding and perhalometallate ions: a supramolecular synthetic strategy for new inorganic materials. | A synthetic strategy for constructing ionic hydrogen-bonded materials by combining perhalometallate anions with cations able to serve as hydrogen bond donors is presented. The approach is based on identification of well defined hydrogen bond acceptor sites on the anions by a combination of experimental and theoretical ... |
11959945 | Biomimetic self-assembly of a functional asymmetrical electronic device. | This paper introduces a biomimetic strategy for the fabrication of asymmetrical, three-dimensional electronic devices modeled on the folding of a chain of polypeptide structural motifs into a globular protein. Millimeter-size polyhedra-patterned with logic devices, wires, and solder dots-were connected in a linear stri... |
11959944 | Cluster self-assembly of di[gold(I)]halonium cations. | Treatment of gold(I) halide complexes of the type L-Au-X [where L = PPh(3), PEt(3) with X = Cl, Br, I, or L = 2,6-(MeO)(2)C(6)H(3)PPh(2) with X = Cl] with AgSbF(6) in the molar ratio 2:1 in dichloromethane/tetrahydrofuran at -78 degrees C affords high yields of di[gold(I)]halonium salts of the formula [X[Au(PR(3))](2)]... |
11959943 | Using multimodal ligands to influence network topology in silver(I) coordination polymers. | A range of Ag(I) one- and two-dimensional coordination frameworks has been prepared and structurally characterized by using the multimodal ligand 3,6-di-pyrazin-2-yl-(1,2,4,5)-tetrazine, which offers both monodentate and chelating binding sites. It is demonstrated that multimodal ligands can be used to prepare coordina... |
11959942 | Geometric requirements and examples of important structures in the assembly of square building blocks. | The basic structures for linking squares into polyhedra and networks (reticulation) are enumerated, and corresponding examples are described in which crystals were synthesized by linking paddle wheel (square) units into metal-organic frameworks (MOFs)--named MOF-102 to MOF-112. |
11959941 | New supramolecular trigonal prisms from zinc(II)- 1,4,7,10-tetraazacyclododecane (cyclen) complexes and trithiocyanurate in aqueous solution. | The multiple bonding between multinuclear zinc(II)-1,4,7,10-tetraazacyclododecane (cyclen, a 12-membered tetraamine) complexes and multidentate ligands is an effective method for constructing supramolecular complexes having well defined and distinct structures in aqueous solution. Herein we present examples of supramol... |
11959940 | Systematic assembly of the double molecular boxes: [Cs subset [CpCo(CN)(3)](4)[Cp*Ru](3)] as a tridentate ligand. | Cubic cage compounds composed of Co-CN-Ru linkages have been prepared which illustrate the following features: (i) new motifs for alkali metal ion complexation (i.e., cationic receptors for cations), (ii) a new family of triaza-metalloligands, and (iii) a double box-like cage. The cages are synthesized by the condensat... |
11959939 | Substituent effects on cation-pi interactions: a quantitative study. | A synthetic supramolecular complex has been adapted to quantify cation-pi interactions in chloroform by using chemical double-mutant cycles. The interaction of a pyridinium cation with the pi-face of an aromatic ring is found to be very sensitive to the pi-electron density. Electron-donating substituents lead to a stro... |
11959938 | "Size-selectivity" in the template-directed assembly of dinuclear triple-stranded helicates. | The self-assembly of supramolecular structures depends on a subtle interplay of a series of different control mechanisms. The geometric as well as electronic complementarity of the molecular building blocks is crucial for the specific formation of defined supramolecular species. In addition, secondary effects, like tem... |
11959937 | Adjusting the binding thermodynamics, kinetics, and orientation of guests within large synthetic hydrophobic pockets. | Kinetic analysis of the host guest complexation of a large, open molecular basket and a highly complementary adamantoid guest reveals that for these types of systems a dissociative mechanism is in operation. Hence, the resident adamantyl guest must completely vacate the cavity before another guest molecule can move in ... |
11959936 | Guest-induced organization of an optimal receptor from a dynamic receptor library: spectroscopic screening. | Complexation of a cis-protected palladium ion and a family of exo-bidentate and -tridentate ligands results in the formation of an equilibrium mixture of numerous metal-linked receptors that are referred to as a dynamic receptor library. We found that a guest induced the selective formation of the optimal receptor of i... |
11959935 | Biomimetic macrocyclic receptors for carboxylate anion recognition based on C-linked peptidocalix[4]arenes. | Two neutral macrobicyclic anion receptors 4 and 6, containing a calix[4]arene in the cone conformation, two l-alanine units, and a 2,6-diacylpyridine or a phthaloyl bridge, are described. The x-ray crystal structure of the acetone complexes of the pyridine containing macrocycle 6 shows the four amide NH groups to be in... |
11959934 | Factors affecting the threading of axle molecules through macrocycles: binding constants for semirotaxane formation. | The threading of more or less linear axle molecules through macrocyclic molecules, a fundamental process relating to the formation of interlocked molecular structures, has been investigated through the study in acetone of the equilibrium constants for the formation of pseudorotaxanes by NMR methods. The 30 new axle mol... |
11959933 | Supramolecular recognition: on the kinetic lability of thermodynamically stable host-guest association complexes. | A molecular receptor consisting of a spacer bearing two cofacially disposed terpyridyl-palladium-ligand (terpy-Pd-L) units rigidly separated by about 7 A has been investigated for molecular recognition of planar aromatic molecules. It is found that although the receptor forms stable 1:2 host-guest association complexes... |
11959932 | Supramolecular chemistry and self-assembly. | Supramolecular systems--their successes, problems, and potential--are discussed with allusion to specific examples. |
11959929 | Beyond molecules: self-assembly of mesoscopic and macroscopic components. | Self-assembly is a process in which components, either separate or linked, spontaneously form ordered aggregates. Self-assembly can occur with components having sizes from the molecular to the macroscopic, provided that appropriate conditions are met. Although much of the work in self-assembly has focused on molecular ... |
11959114 | The Fluorosome technique for investigating membrane on- and off-loading of drugs by beta-CD and sonicated SUV. | The application of the Fluorosome technique to test drug delivery systems is described. Fluorosomes, egg phosphatidylcholine liposomes with bilayer embedded fluorophores, were employed to investigate the ability of sonicated small unilamellar vesicles (sSUV) and beta-cyclodextrins (beta-CD) to deliver drugs into or ext... |
11959497 | Complexity and simplicity of ligand-macromolecule interactions: the energy landscape perspective. | The energy landscape approach has contributed to recent progress in understanding the complexity and simplicity of ligand-macromolecule interactions. Significant advances in computational structure prediction of ligand-protein complexes have been made using approaches that include the effects of protein flexibility and... |
11959491 | Modeling supramolecular assemblages. | There has been some progress (but not much) in simulating supramolecular assemblages in the past year. The two main technical advances have been, firstly, the establishment of a protocol for extracting equilibrium thermodynamic data from forced (i.e. nonequilibrium) simulations and experiments, and, secondly, the devel... |
11959804 | 2-Chloro N(6)-methyl-(N)-methanocarba-2'-deoxyadenosine-3',5'-bisphosphate is a selective high affinity P2Y(1) receptor antagonist. | 1. We reported previously that bisphosphate derivatives of adenosine are antagonists of the P2Y(1) receptor and that modification of the ribose in these analogues is tolerated in the P2Y(1) receptor binding pharmacophore. 2. Here we delineate the pharmacological activity of one such non-nucleotide molecule, 2-chloro N(... |
11955816 | Nasal absorption enhancement strategies for therapeutic peptides: an in vitro study using cultured human nasal epithelium. | This study examined the potential usefulness of cultured human nasal epithelium as a model to investigate nasal absorption enhancement strategies for therapeutic peptides. The transport of leucine enkephalin (Leu-Enk) in the presence of bestatin and puromycin, respectively and various combinations of these protease inh... |
11955051 | Heteroatom-directed aromatic lithiation: a versatile route to the synthesis of organochalcogen (Se, Te) compounds. | Chiral and achiral organochalcogen compounds bearing a heteroatom in close proximity are easily accessible via the directed aromatic lithiation route. The lithium chalcogenolates prepared by the insertion of selenium or tellurium into the C-Li bond are used to synthesize various chalcogen compounds such as Se/Te, N don... |
11954825 | Acute hypoxemia in humans enhances the neutrophil inflammatory response. | The neutrophil (PMN) is regarded as a key component in the hyperinflammatory response known as the systemic inflammatory response syndrome. Acute respiratory distress syndrome (ARDS) and subsequent multiple organ failure (MOF) are related to the severity of this hyperinflammation. ICU patients who are at highest risk o... |
11952368 | A hybrid consisting of coordination polymer and noncovalent organic networks: a highly ordered 2-D phenol network assembled by edge-to-face pi-pi interactions. | A 2-D metal-organic open framework having 1-D channels, [Cu(C(10)H(26)N(6))](3)[C(6)H(3)(COO)(3)](2).18H(2)O (1), was constructed by the self-assembly of the Cu(II) complex of hexaazamacrocycle A (A = C(10)H(26)N(6)) with sodium 1,3,5-benzenetricarboxylate (BTC(3)(-)) in DMSO-H(2)O solution. 1 crystallizes in the trigo... |
11952360 | Arsenic(III) halide complexes with acyclic and macrocyclic thio- and selenoether coligands: synthesis and structural properties. | The preparations of the new complexes [AsBr(3)[MeS(CH(2))(2)SMe]], [AsX(3)([9]aneS(3))] (X = Cl, Br or I; [9]aneS(3) = 1,4,7-trithiacyclononane), [AsCl(3)([14]aneS(4))] ([14]aneS(4) = 1,4,8,11-tetrathiacyclotetradecane), [AsX(3)([8]aneSe(2))] ([8]aneSe(2) = 1,5-diselenacyclooctane), [(AsX(3))(2)([16]aneSe(4))] ([16]ane... |
11953309 | TCR signal initiation machinery is pre-assembled and activated in a subset of membrane rafts. | Recent studies suggest that rafts are involved in numerous cell functions, including membrane traffic and signaling. Here we demonstrate, using a polyoxyethylene ether Brij 98, that detergent-insoluble microdomains possessing the expected biochemical characteristics of rafts are present in the cell membrane at 37 degre... |
11952479 | Cyclodextrins in eye drop formulations: enhanced topical delivery of corticosteroids to the eye. | Cyclodextrins are cylindrical oligosaccharides with a lipophilic central cavity and hydrophilic outer surface. They can form water-soluble complexes with lipophilic drugs, which 'hide' in the cavity. Cyclodextrins can be used to form aqueous eye drop solutions with lipophilic drugs, such as steroids and some carbonic a... |
11950370 | Calix[4]arenes linked to multiple bidentate N-donors: potential ligands for synthetic modeling of multinuclear metalloenzymes. | A series of calix[4]arenes incorporating three or four bidentate diamines or pyridylamines attached at the "upper rim" were synthesized via practical protocols. Proof of structure was obtained in one instance by X-ray crystallography. These molecules are designed for general use as ligands for the preparation of multin... |
11950344 | Synthesis of disubstituted cucurbit[6]uril and its rotaxane derivative. | Synthesis of diphenyl cucurbit[6]uril (CB[6]) has been achieved via co-oligomerization of diphenyl glycoluril and unsubstituted glycoluril. The unsymmetrically substituted CB[6], Ph(2)CB[6], was further converted to a rotaxane incorporating bis(dinitrophenyl)spermine. [reaction: see text] |
11950949 | Kinesin-II is required for flagellar sensory transduction during fertilization in Chlamydomonas. | The assembly and maintenance of eucaryotic flagella and cilia depend on the microtubule motor, kinesin-II. This plus end-directed motor carries intraflagellar transport particles from the base to the tip of the organelle, where structural components of the axoneme are assembled. Here we test the idea that kinesin-II al... |
11950943 | A phosphorylated cytoplasmic autoantigen, GW182, associates with a unique population of human mRNAs within novel cytoplasmic speckles. | A novel human cellular structure has been identified that contains a unique autoimmune antigen and multiple messenger RNAs. This complex was discovered using an autoimmune serum from a patient with motor and sensory neuropathy and contains a protein of 182 kDa. The gene and cDNA encoding the protein indicated an open r... |
11950931 | Phosphoinositides regulate membrane-dependent actin assembly by latex bead phagosomes. | Actin assembly on membrane surfaces is an elusive process in which several phosphoinositides (PIPs) have been implicated. We have reconstituted actin assembly using a defined membrane surface, the latex bead phagosome (LBP), and shown that the PI(4,5)P(2)-binding proteins ezrin and/or moesin were essential for this pro... |
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