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Synthesis and Characterization of a Combined Main-Chain/Side-Chain Liquid-Crystalline Polymer Exhibiting Both Thermotropic and Lyotropic Characteristics and Its Lyotropic Phase Behavior

Ming Zhou、Chang Dae Han2005-10-12Macromolecules

A combined main-chain/side-chain liquid-crystalline polymer (PSHQ4−7CNCOOH), which is composed of poly[(phenylsulfonyl- p -phenylenene 1,4-tetramethylene bis(oxybenzoate)] (PSHQ4) as the main-chain backbone and 8-[(4-cyano-4‘-phenyl)oxy]octanoic acid (7CNCOOH) as the side-chain mesogenic groups, has been synthesized.…

Liquid Crystal Research AdvancementsBlock Copolymer Self-AssemblyAdvanced Materials and Mechanics

Langmuir and Grafted Monolayers of Photochromic Amphiphilic Monodendrons of Low Generations

Kirsten L. Genson、Jason Holzmuller、Ovette F. Villacencio 等 6 位作者2005-10-12The Journal of Physical Chemistry B

Four generations of monodendrons with multiple dodecyl alkyl tails (AA-N, N representing number of alkyl tails from 1 to 8), an azobenzene spacer group, and a carboxylic acid polar head have been studied at the air-water and air-solid interface using AFM, GIXD, X-ray reflectivity, and UV-vis spectrometry. The one and…

Liquid Crystal Research AdvancementsPorphyrin and Phthalocyanine ChemistryPhotochromic and Fluorescence Chemistry

The Widom insertion method and ordering in small hard-sphere systems

Roel P. A. Dullens、Dirk G. A. L. Aarts、Willem K. Kegel 等 4 位作者2005-10-12Molecular Physics

We study a small system of spherically confined hard spheres using the Widom particle insertion method as an indicator for the ordering transition. By Monte Carlo simulations we determine the insertion probability as a function of the number of particles and the box size. We find an increase of the insertion probabili…

Phase Equilibria and ThermodynamicsMaterial Dynamics and PropertiesTheoretical and Computational Physics

Entrapment of Organic Solutes by the Water Cage in the Nanochannel of MCM-41

Masaharu Okazaki、Kazumi Toriyama2005-10-12The Journal of Physical Chemistry B

The effect of MCM-41 on the ESR spectrum of an aqueous spin probe solution was observed. The sharp ESR spectrum turns into a rather broad characteristic one leaving a sharper signal as the minor component, immediately after the addition of MCM-41 powder to the system. This observation indicates that MCM-41 traps the s…

Mesoporous Materials and CatalysisPorphyrin and Phthalocyanine ChemistrySpectroscopy and Quantum Chemical Studies

Effect of prestrain on martensitic transformation in a Ti46.4Ni47.6Nb6.0 superelastic alloy and its application to medical stents

Toshiyuki Takagi、Yuji Sutou、Ryosuke Kainuma 等 5 位作者2005-10-12Journal of Biomedical Materials Research Part B Applied Biomaterials

The effect of applied strain on martensitic transformation in a superelastic Ti(46.4)Ni(47.6)Nb(6.0) alloy at room temperature was investigated by tensile tests, differential scanning calorimetry measurements, and X-ray diffraction. Reverse transformation starting (A(s)) and finishing (A(f)) temperatures increased wit…

Shape Memory Alloy TransformationsHigh Entropy Alloys StudiesTitanium Alloys Microstructure and Properties

Nonnatural amino acid incorporation into the methionine 214 position of the metzincin Pseudomonas aeruginosa alkaline protease

Paula Walasek、John F. Honek2005-10-12BMC Biochemistry

BACKGROUND: The alkaline protease from Pseudomonas aeruginosa (AprA) is a member of the metzincin superfamily of metalloendoproteases. A key feature of these proteases is a conserved methionine-containing 1,4-tight beta turn at the base of the active site zinc binding region. RESULTS: To explore the invariant methioni…

Protease and Inhibitor MechanismsEnzyme Structure and FunctionCancer Research and Treatments

Schottky barrier formed by network of screw dislocations in SrTiO3

Xin Guo、Zaoli Zhang、Wilfried Sigle 等 5 位作者2005-10-12Applied Physics Letters

A network of screw dislocations was artificially created in SrTiO3, and characterized by transmission electron microscopy (TEM). Slight expansion of the dislocation core was observed by TEM. The composition of the dislocation core was quantified by electron energy loss spectroscopy, which reveals a 13±5% Ti∕O ratio in…

Ferroelectric and Piezoelectric MaterialsMagnetic and transport properties of perovskites and related materialsElectronic and Structural Properties of Oxides

Drug entrapment in silica microspheres through a single step sol–gel process and in vitro release behavior

Elvan Yılmaz、Murat Bengisu2005-10-12Journal of Biomedical Materials Research Part B Applied Biomaterials

A single step sol-gel process was used to precipitate silica microspheres containing ibuprofen or naproxen for controlled drug delivery applications. The drug release behavior from these systems was analyzed in vitro. Pure ibuprofen and naproxen exhibited linear release with time, while sol-gel silica entrapped drugs…

Drug Solubulity and Delivery SystemsMesoporous Materials and CatalysisAdvanced Drug Delivery Systems

A Novel Bis(zinc–porphyrin)–Oxoporphyrinogen Donor–Acceptor Triad: Synthesis, Electrochemical, Computational and Photochemical Studies

Jonathan P. Hill、Atula S. D. Sandanayaka、Amy L. McCarty 等 10 位作者2005-10-12European Journal of Organic Chemistry

Abstract The first example of a porphyrin‐quinonoid donor–acceptor triad featuring (tetraphenylporphinato)zinc( II ) moieties covalently attached to an oxoporphyrinogen through its macrocyclic nitrogen atoms is reported. This arrangement of chromophores results in an interesting interplay between the electron‐donating…

Metal complexes synthesis and propertiesPhotosynthetic Processes and MechanismsPorphyrin and Phthalocyanine Chemistry

Polymorphism in Benzamide

William I. F. David、Kenneth Shankland、Colin R. Pulham 等 6 位作者2005-10-12Angewandte Chemie

Längst überfällig: Die Kristallstruktur der metastabilen Form von Benzamid (siehe Bild), deren Existenz seit über 170 Jahren bekannt war, ist endlich aufgeklärt worden – durch eine Kombination von In-situ-Kristallisation, Hochgeschwindigkeits-Synchrotronröntgenpulverbeugung und globalen Optimierungsmethoden zur Strukt…

Crystallography and molecular interactionsCrystallization and Solubility StudiesX-ray Diffraction in Crystallography

pH-Induced Reversible Conformational and Morphological Regulation of Polyleucine Grafted Polyallylamine Assembly in Solution

Masahiro Higuchi、Takateru Inoue、Hidenori Miyoshi 等 4 位作者2005-10-12Langmuir

One of the essential parts in the molecular mechanism of biological properties is the structural changes of proteins induced by stimuli. An amphiphilic copolymer, poly(L-leucine) grafted polyallylamine as a simple model of proteins, has been prepared by NCA polymerization with free amino groups of polyallylamine as an…

Advanced Polymer Synthesis and CharacterizationSupramolecular Self-Assembly in MaterialsDendrimers and Hyperbranched Polymers

Optical properties of Si and Ge nanocrystals: Parameter‐free calculations

L. E. Ramos、Hans‐Christian Weissker、J. Furthmüller 等 4 位作者2005-10-12physica status solidi (b)

Abstract An overview is given on the electronic and optical properties of Si and Ge nanocrystals. We model free‐standing Si and Ge nanocrystals passivated with H, with up to 363 group‐IV atoms and 276 H and oxidized nanocrystals with additional silicon oxide shells, e.g. Si 41 (O 60 Si 42 )(O 108 Si 64 )H 148 . The re…

Quantum Dots Synthesis And PropertiesSemiconductor materials and devicesSilicon Nanostructures and Photoluminescence

Why Twins Do Not Grow at the Speed of Sound All the Time

P. G. Oberson、Sreeramamurthy Ankem2005-10-12Physical Review Letters

Deformation twinning occurs in various materials including metals, intermetallics, ceramics, superconductors, and even geological systems. The rate of twin growth depends on the material system, but there are no crystallographic models to understand the mechanisms of slow twin growth. The physics of twin growth is pre…

Microstructure and mechanical propertiesIntermetallics and Advanced Alloy PropertiesTitanium Alloys Microstructure and Properties

A.C. Conductivity and Dielectric Properties of Polycarbonate Sheet

M. S. Aziz、H. M. El-Mallah2005-10-12International Journal of Polymeric Materials

The a.c. conductivity σa.c(ω), the dielectric constant ϵ′ and dielectric loss ϵ″ of polycarbonate sheet have been studied in the frequency range 1.5 × 102–5 × 106 Hz and temperature range 294–473 K. A.c. conductivity σa.c(ω) results show that it depends strongly on the frequency and slightly on the temperature, with a…

Material Dynamics and PropertiesConducting polymers and applicationsElectrochemical Analysis and Applications

Surface State and Composition of a Disperse Pd Catalyst after Its Exposure to Ethylene

D. Teschner、Ute Wild、Robert Schlögl 等 4 位作者2005-10-12The Journal of Physical Chemistry B

Pd black was exposed to ethylene alone or in its mixture with hydrogen at 300 and 573 K. The samples were investigated by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Room temperature introduction of C(2)H(4) (also in the presence of H(2)) induced a binding-energy (BE) shift…

Advanced Chemical Physics StudiesCatalytic Processes in Materials ScienceCatalysis and Oxidation Reactions

Calculations of organic‐solvent dispersions of single‐wall carbon nanotubes

Francisco Torrens2005-10-12International Journal of Quantum Chemistry

Abstract The aqueous solubility S w and 1‐octanol–( P o ), cyclohexane–( P ch ), and chloroform–( P cf ) water partition coefficients are calculated. The properties of single‐wall carbon nanotubes (SWNT) are related to the indices ( n, m ) designating the chiral vector. SWNTs are classified in zigzag ( n , 0), armchai…

Carbon Nanotubes in CompositesGraphene research and applicationsNanopore and Nanochannel Transport Studies

Monte Carlo calculations for the intrinsic viscosity of several dendrimer molecules

Juan J. Freire、Esteban Rodrı́guez、Ana M. Rubio2005-10-12The Journal of Chemical Physics

We have performed Monte Carlo simulations to reproduce the intrinsic viscosity corresponding to different generation of several types of dendrite molecules: polyamidoamine dendrimers with an ethylendiamine core, polypropylene-imine with a diaminobutane core, and monodendrons and tridendrons of polybenzylether. With th…

Polymer Surface Interaction StudiesLubricants and Their AdditivesDendrimers and Hyperbranched Polymers

Bio-Inspired Calix[4]arene Additives for Crystal Growth Modification of Inorganic Materials

Franca Jones、Mauro Mocerino、Mark I. Ogden 等 5 位作者2005-10-12Crystal Growth & Design

Crystal growth of inorganic materials, calcium carbonate, barium sulfate, and calcium oxalate, was studied in the presence of calix[4]arene additives functionalized with aspartic or glutamic acids at the lower rim. The additives were synthesized by reaction of the appropriate amino acid ester with 5,11,17,23-tetra- te…

Bone Tissue Engineering MaterialsCalcium Carbonate Crystallization and InhibitionCrystallization and Solubility Studies

Influence of bridge topology and torsion on the intramolecular electron transfer

Vega Lloveras、J. Vidal-Gancedo、Daniel Ruiz‐Molina 等 7 位作者2005-10-12Faraday Discussions

To study molecules able to act as good "molecular wires", intramolecular electron transfer between two triphenylmethyl redox centers connected by bridges with different topologies and substituents have been studied in solution, both by UV-Vis-NIR and EPR spectroscopies. The synthetic methodology used allows a complete…

Porphyrin and Phthalocyanine ChemistryMolecular Junctions and NanostructuresPhotochemistry and Electron Transfer Studies

Kinetic and Equilibrium Binding Analysis of Protein−Ligand Interactions at Poly(amidoamine) Dendrimer Monolayers

Mi-Young Hong、Dohoon Lee、Hak‐Sung Kim2005-10-12Analytical Chemistry

The interaction of streptavidin (SA) with a biotinylated surface has been of great interest in the development of an interfacial layer for protein immobilization based on self-assembled monolayers (SAMs) and polymeric layers. Here, we demonstrate the unique characteristics of protein-ligand interactions on dendrimer m…

Polymer Surface Interaction StudiesDendrimers and Hyperbranched PolymersAdvanced Biosensing Techniques and Applications