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Combined molecular and supramolecular bottom-up nanoengineering for enhanced nonlinear optical response: Experiments, modeling, and approaching the fundamental limit

Javier Pérez‐Moreno、Inge Asselberghs、Kai Song 等 13 位作者2007-02-21The Journal of Chemical Physics

The authors study the combination of two independent strategies that enhance the hyperpolarizability of ionic organic chromophores. The first molecular-level strategy is the extension of the conjugation path in the active chromophore. The second supramolecular-level strategy is the bottom-up nanoengineering of an incl…

Crystallography and molecular interactionsNonlinear Optical Materials ResearchNonlinear Optical Materials Studies

Origin of Near-Infrared Absorption and Large Second Hyperpolarizability in Oxyallyl Diradicaloids: A Three-State Model Approach

Kada Yesudas、K. Bhanuprakash2007-02-21The Journal of Physical Chemistry A

Bis(benzofuranonyl)methanolate (BM4i4i) dye and croconate dyes (derivatives of oxyallyl molecules) in general are known to have intense transitions in the near-infrared (NIR) region, indicating small transition energies and large transition dipole moments. These molecules have been reported in the literature to have v…

Nonlinear Optical Materials ResearchPhotochemistry and Electron Transfer StudiesOrganic Chemistry Cycloaddition Reactions

Mechanistic Study of Iron(III) [Tetrakis(pentafluorophenyl)Porphyrin Triflate (F20TPP)Fe(OTf) Catalyzed Cyclooctene Epoxidation by Hydrogen Peroxide

Ned A. Stephenson、Alexis T. Bell2007-02-21Inorganic Chemistry

We have recently proposed a mechanism for the epoxidation of cyclooctene by H2O2 catalyzed by iron(III) [tetrakis(pentafluorophenyl)]porphyrin chloride, (F20TPP)FeCl, in solvent containing methanol [Stephenson, N. A.; Bell, A.T. Inorg. Chem. 2006, 45, 2758-2766]. In that study, we found that catalysis did not occur un…

Magnetism in coordination complexesPorphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation Mechanisms

Structure and rheology of organoclay suspensions

H. E. King、Scott T. Milner、Min Lin 等 5 位作者2007-02-21Physical Review E

We have characterized a montmorillonite-based organoclay dispersed in three different nonaqueous solvents using a combination of x-ray scattering, small-angle neutron scattering (SANS), and ultrasmall angle neutron scattering (USANS), together with rheological measurements. Consistent with these measurements, we prese…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesRheology and Fluid Dynamics Studies

Adsorption of Pd Atoms and Dimers on the TiO2 (110) Surface: A First Principles Study

Javier Fdez. Sanz、Antonio M. Márquez2007-02-21The Journal of Physical Chemistry C

The adsorption of Pd-isolated atoms and dimers on the (110) surface of rutile TiO 2 has been investigated in a range of coverage using a periodic supercell approach within density functional theory using a generalized gradient approach and plane-wave basis sets. Pd atoms prefer to adsorb on the surface channels near t…

Catalytic Processes in Materials ScienceCopper-based nanomaterials and applicationsElectronic and Structural Properties of Oxides

BaCe1-xPdxO3-δ (0 ≤ x ≤ 0.1): Redox Controlled Ingress and Egress of Palladium in a Perovskite

Jun Li、Udayshankar G. Singh、Joseph W. Bennett 等 10 位作者2007-02-21Chemistry of Materials

We demonstrate using a combination of X-ray and neutron diffraction and X-ray photoelectron spectroscopy that Pd 2+ ions can be substituted for Ce in perovskite BaCeO 3 and that, under oxidizing conditions, BaCe 1 - x Pd x O 3 - δ (0 ≤ x ≤ 0.1) compositions can be prepared. Neutron diffraction has helped verify that δ…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsElectronic and Structural Properties of Oxides

Reverse-Keggin Ions: Polycondensation of Antimonate Ligands Give Inorganic Cryptand

Viswanathan Baskar、Maheswaran Shanmugam、Madeleine Helliwell 等 5 位作者2007-02-21Journal of the American Chemical Society

Reverse-Keggin ions are reported in which a p-block element (antimony) occupies the twelve vertices of a truncated tetrahedron while a d-block element (manganese or zinc) occupies the tetrahedral central cavity. The exterior of the reverse-Keggins also acts as tridentate ligands to further d-block centers.

Metal-Organic Frameworks: Synthesis and ApplicationsPolyoxometalates: Synthesis and ApplicationsCovalent Organic Framework Applications

Effect of peroxide crosslinking on thermal and mechanical properties of poly(ε‐caprolactone)

Changyu Han、Xianghai Ran、Xuan Su 等 6 位作者2007-02-21Polymer International

Abstract Poly(ε‐caprolactone) (PCL), a saturated polyester, derived from ring‐opening polymerization of ε‐caprolactone, was chemically crosslinked with various amounts of benzoyl peroxide (BPO) by a two‐step method by first evenly dispersing the BPO into the PCL matrix and then crosslinking at elevated temperature. Th…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

Blends of Poly(methacrylate) Block Copolymers with Photoaddressable Segments

Thomas Breiner、Klaus Kreger、Rainer Hagen 等 8 位作者2007-02-21Macromolecules

The paper presents the synthesis of azobenzene-functionalized block copolymers based on a poly(methyl methacrylate) (PMMA) segment and an azobenzene-functionalized poly(hydroxyethyl methacrylate) segment, and a basic study of blending these block copolymers with homopolymers is given. Two diblock copolymers, prepared…

Liquid Crystal Research AdvancementsAdvanced Polymer Synthesis and CharacterizationSynthesis and Properties of Aromatic Compounds

Non‐Isothermal Crystallisation Kinetics of In Situ Prepared Poly(ε‐caprolactone)/Surface‐Treated SiO2 Nanocomposites

Alexandros A. Vassiliou、George Z. Papageorgiou、Dimitris S. Achilias 等 4 位作者2007-02-21Macromolecular Chemistry and Physics

Abstract Poly( ε ‐caprolactone)/silica nanocomposites were prepared by the in situ technique. The molecular weight of the polymer was slightly reduced on increasing the amount of filler. Most likely, the silica nanoparticles affected the action of the polymerisation catalyst. Furthermore, it was found that especially…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

Hexagonally Ordered Nanostructures Comprised of a Flexible Disk-like Molecule with High Self-Assembling Properties at Neutral and Cationic States

Masashi Hasegawa、Hideo Enozawa、Youhei Kawabata 等 4 位作者2007-02-21Journal of the American Chemical Society

A novel amphiphilic TTF hexamer 1 with a flexible disk-like structure and strong self-aggregation properties has been synthesized. Nanowires fabricated from both 1 and its cation radical 1 •+ in CHCl 3 /hexane solutions have a hexagonal columnar structure. In contrast, drop-cast films of 1 and 1 •+ exhibit an edge-to-…

Metal-Organic Frameworks: Synthesis and ApplicationsMagnetism in coordination complexesOrganic and Molecular Conductors Research

Ab initiostudy of hydrogen interaction with pure and nitrogen-doped carbon nanotubes

Zhiyong Zhang、Kyeongjae Cho2007-02-21Physical Review B

Detailed studies of mechanisms for hydrogen dissociative adsorption and diffusion on pure and nitrogen-doped (8, 0) carbon nanotubes are carried out using the first-principles density functional theory method. (1) For pure carbon nanotubes, we have identified the energetically most favorable dissociative pathway for h…

Carbon Nanotubes in CompositesGraphene research and applicationsHydrogen Storage and Materials

Highly-Efficient Purification of Native Polyhistidine-Tagged Proteins by Multivalent NTA-Modified Magnetic Nanoparticles

Jason S. Kim、C. Alexander Valencia、Rihe Liu 等 4 位作者2007-02-21Bioconjugate Chemistry

A new bis-nitrilotriacetic acid (NTA) chelate with catechol anchor was synthesized and immobilized on superparamagnetic iron oxide nanoparticles. When loaded with Ni(II), these bis-NTA-immobilized nanoparticles were shown to bind polyhistidine (His x 6-tagged) fusion proteins in their native, folded conformations that…

Nanoparticle-Based Drug DeliveryGlycosylation and Glycoproteins ResearchChemical Synthesis and Analysis

The RPB7 Orthologue E′ Is Required for Transcriptional Activity of a Reconstituted Archaeal Core Enzyme at Low Temperatures and Stimulates Open Complex Formation

Souad Naji、Sebastian Grünberg、Michael Thomm2007-02-21Journal of Biological Chemistry

RNA polymerases from Archaea and Eukaryotes consist of a core enzyme associated with a dimeric E'F (Rpb7/Rpb4) subcomplex but the functional contribution of the two subunit subcomplexes to the transcription process is poorly understood. Here we report the reconstitution of the 11-subunit RNA polymerase and of the core…

Protein Structure and DynamicsEnzyme Structure and FunctionBiochemical and Molecular Research

Topological Changes in Bipolar Nematic Droplets under Flow

Alberto Fernández‐Nieves、Darren R. Link、M. Márquez 等 4 位作者2007-02-21Physical Review Letters

Bipolar liquid crystal drops moving inside microchannels exhibit periodic director field transformations due to induced circulating flows inside them. These modifications are characterized by changes in the type of point surface disclinations; they periodically change from splay to bend disclinations, implying the dro…

Liquid Crystal Research AdvancementsNonlinear Dynamics and Pattern FormationAdvanced Materials and Mechanics

Polymerization of Aniline on Polyaniline Membranes

Natalia V. Blinova、Jaroslav Stejskal、Miroslava Trchová 等 5 位作者2007-02-21The Journal of Physical Chemistry B

When solutions of aniline hydrochloride and ammonium peroxydisulfate were separated by a semipermeable cellulose membrane, the reactants met at the membrane and produced a polyaniline (PANI) membrane at the interface. The oxidative polymerization of aniline then proceeded in situ on the PANI-cellulose composite membra…

Electrochemical sensors and biosensorsConducting polymers and applicationsAnalytical Chemistry and Sensors

Poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) composite biomaterials for bone tissue regeneration: In vitro performance assessed by osteoblast proliferation, osteoclast adhesion and resorption, and macrophage proinflammatory response

Simon M. Cool、B. Kenny、Andy Wu 等 7 位作者2007-02-21Journal of Biomedical Materials Research Part A

The efficacy of composite materials for bone tissue engineering is dependent on the materials' ability to support bone regeneration whilst inducing a minimal inflammatory response. In this study we examined the in vitro osteogenic and inflammatory properties of poly(3-hydroxybutyrate-co-3-valerate) (PHBV) with various…

Bone Tissue Engineering MaterialsOrthopaedic implants and arthroplastybiodegradable polymer synthesis and properties

Deactivation Studies over Ni−K/CeO2−Al2O3 Catalyst for Dry Reforming of Methane

Nandini A. Pechimuthu、Kamal Kishore Pant、Subhash Chander Dhingra2007-02-21Industrial & Engineering Chemistry Research

The activity of 13.5Ni−2K/10CeO 2 −Al 2 O 3 catalyst was tested for 60 h time on stream (TOS) for the carbon dioxide reforming of methane at three different temperatures (650, 700, and 750 °C). The amount of coke deposited on the catalyst at different time intervals was estimated by thermogravimetric analysis (TGA). R…

Catalytic Processes in Materials ScienceCatalysts for Methane ReformingCatalysis and Oxidation Reactions

On the routine use of soft X-rays in macromolecular crystallography. Part IV. Efficient determination of anomalous substructures in biomacromolecules using longer X-ray wavelengths

Christoph Mueller‐Dieckmann、Santosh Panjikar、Andrea Schmidt 等 10 位作者2007-02-21Acta Crystallographica Section D Biological Crystallography

23 different crystal forms of 19 different biological macromolecules were examined with respect to their anomalously scattering substructures using diffraction data collected at a wavelength of 2.0 A (6.2 keV). In more than 90% of the cases the substructure was found to contain more than just the protein S atoms. The…

Protein Structure and DynamicsDNA Repair MechanismsEnzyme Structure and Function

Enhancement of stiffness, strength, ductility and toughness of poly(ethylene oxide) using phenoxy-grafted multiwalled carbon nanotubes

Bingxing Yang、Jiahua Shi、K. P. Pramoda 等 4 位作者2007-02-21Nanotechnology

Phenoxy (poly(hydroxyether of bisphenol-A), also known as poly(bisphenol-A- co -epichlorohydrin)) was grafted onto multiwalled carbon nanotubes (MWNTs) by a reactive blending process. Reactions between terminal glycidyl groups of phenoxy and carboxylic acid groups of acidified MWNTs resulted in the grafting of phenoxy…

Carbon Nanotubes in CompositesPolymer crystallization and propertiesPolymer Nanocomposites and Properties