Theoretical investigations of 2-vinylpyridine stereoselective polymerization catalyzed by cationic yttrium complexes with different ancillary ligands.

The polymerization mechanism of 2-vinylpyridine catalyzed by cationic yttrium complexes with diverse ancillary ligands, specifically [L1Y(CHSiMe)(THF)] [L1 = (2,6-EtCH)NC(Me)CHC(Me)N(2,6-EtCH)] (Y-1), [L2Y(CHSiMe)(THF)] [L2 = (2,6-ClCH)NC(Me)CHC(Me)N(2,6-ClCH)] (Y-2), and [L3Y(CHSiMe)(THF)] [L3 = (2,6-CH)NC(Me)CHC(Me)N(2,6-PrCH)] (Y-3), was studied using density functional theory (DFT) calculations. Having achieved an agreement between theory and experiment, it is found that isotactic selectivity induced by Y-1 or Y-2 results from a combination of smaller deformation of the catalyst and stronger electronic effects. Conversely, the Y-3 complex exhibits comparable energy barriers for proceeding either isotactic or syndiotactic pathways, aligning with the production of atactic polymers as seen experimentally.

Host-Guest Interaction Mediated Interfacial Co-Assembly of Cyclodextrin and Bottlebrush Surfactants for Precisely Tunable Photonic Supraballs.

Investigations of host-guest interactions at water-oil (w/o) interfaces are limited in single emulsion systems producing simple self-assembled objects with limited uses. Here, within hierarchically ordered water-in-oil-in-water (w/o/w) multiple emulsion droplets, interfacial self-assembly of (polynorbornene-graft-polystyrene)-block-(polynorbornene-graft-polyethylene glycol) (PNPS-b-PNPEG) bottlebrush block copolymers can be precisely controlled through host-guest interactions. α-Cyclodextrin (α-CD) in the aqueous phase can thread onto PEG side chains of the bottlebrush surfactants adsorbed at the w/o interface, leading to dehydration and collapsed chain conformation of the PEG block.

Chromosomal fragment deletion in APRR2-repeated locus modulates the dark stem color in Cucurbita pepo.

Cp4.1LG15g03420 (CpDsc-1), which encodes a two-component response regulator-like protein (APRR2) in the nucleus, influences dark green stem formation in Cucurbita pepo by regulating the chlorophyll content. Stem color is an important agronomic trait in zucchini (Cucurbita pepo) for robust seeding and high yield.

Data on Tougu Xiaotong capsules may inhibit p38 MAPK pathway-mediated inflammation in vitro.

The Tougu Xiaotong capsule (TXC) is a traditional herbal compound used to treat osteoarthritis (OA) in China. We performed fingerprint analysis with HPLC for the quality control of TXC. Its composition was identified by the comparison of the spectrogram and chromatographic peak of retention time with a reference substance.

Tougu Xiaotong capsules may inhibit p38 MAPK pathway-mediated inflammation: In vivo and in vitro verification.

Ethnopharmacological Relevance: Tougu Xiaotong capsules (TXC) are an herbal compound commonly used to treat osteoarthritis (OA) in China.

Aim Of The Study: We attempted to verify TXC's therapeutic effects and mechanisms related to the p38 mitogen-activated protein kinase (MAPK) pathway in vivo and in vitro.

Materials And Methods: TXC's therapeutic effects were assessed by observing cartilage degeneration and inflammatory factors in a modified Hulth's model (in vivo) and a lipopolysaccharides (LPS)-exposed cellular model (in vitro).

Citric Acid-Treated Zeolite Y (CY)/Zeolite Beta Composites as Supports for Vacuum Gas Oil Hydrocracking Catalysts: High Yield Production of Highly-Aromatic Heavy Naphtha and Low-BMCI Value Tail Oil.

Citric acid-treated zeolite Y (CY) and zeolite beta were mechanically mixed to obtain composite zeolites (CY-Beta) with various zeolite beta contents. The composite zeolites were used as the acid components of hydrocracking catalyst supports. The physical and chemical properties of the supports and catalysts were analyzed by N adsorption-desorption, XRD, SEM, and NH-TPD.

Chelativorans intermedius sp. nov. and proposal to reclassify Thermovum composti as Chelativorans composti comb. nov.

Two Gram-stain-negative, non-endospore-forming, rod-shaped bacteria, strains CC-MHSW-5(T) and A1392, were isolated from water of coastal hot springs located in Taiwan and China, respectively, and investigated for their taxonomic position. The two strains shared identical 16S rRNA gene sequences, a DNA-DNA hybridization value >80% and similar genomic DNA G+C contents (64.3 and 64.

Amphiplicatus metriothermophilus gen. nov., sp. nov., a thermotolerant alphaproteobacterium isolated from a hot spring.

A thermotolerant, Gram-strain-negative, non-spore-forming and strictly aerobic bacterium, designated GU51(T), was isolated from Guhai hot spring in Jimsar county, Xinjiang province, north-west China. Each cell of strain GU51(T) consisted of an oval body and two symmetrical long (3-6 µm) prosthecae. The strain moved by polar flagellum.

[Expression of LIM mineralization protein-1 in the apical papilla and dental pulp tissues of human teeth].

Objective: To examine the expression of LIM mineralization protein-1 (LMP-1) in the apical papilla and dental pulp tissues of human immature permanent teeth and to investigate the role of LMP-1 in the development and maturation of pulp-dentin complex.

Methods: Forty-eight healthy premolars in need of extraction for orthodontic treatment were obtained with 24 immature permanent teeth and 24 mature permanent teeth. After extraction, the apical papilla was detached from the dental pulp in the immature permanent tooth and the dental pulp of mature permanent tooth was rapidly removed.

Anoxybacillus vitaminiphilus sp. nov., a strictly aerobic and moderately thermophilic bacterium isolated from a hot spring.

A strictly aerobic, Gram-stain-positive, motile and spore-forming bacterium, strain 3nP4(T), was isolated from the Puge hot spring located in the south-western geothermal area of China. Strain 3nP4(T) grew at 38-66 °C (optimum 57-60 °C), at pH 6.0-9.

Determination of amino acids by capillary electrophoresis with differential resonant contactless conductivity detector.

The impedance of a capacitively coupled contactless conductivity detector (C(4)D) in capillary electrophoresis (CE) was measured by an impedance analysis method. The influence of solution conductivity and capillary dimension on impedance parameters was investigated. Under the experimental conditions used, 86-99.

Determination of anions using monolithic capillary column ion chromatography with end-to-end differential contactless conductometric detectors under resonance approach.

An end-to-end differential measurement approach with capacitively coupled contactless conductivity detection (C(4)D) was applied to anion-exchange monolithic capillary column ion chromatography. The column was prepared by thermally initiated radical polymerization of poly(glycidyl methacrylate) in a fused-silica capillary of 320 μm i.d.

[The precise assignment of whispering gallery modes for lasing spectra emitting from cylindrical micro-cavities].

Lasers with spherical or cylindrical dielectric resonators supported by whispering gallery modes (WGM) have attracted much interest due to their microscopic size, high cavity Q factor, and low lasing threshold. Cylindrical microcavity lasers based on the gain only in the evanescent field region of whispering gallery modes have been demonstrated in our recent works. The gain was excited by the evanescent wave of longitudinal optical pumping along the optical fiber.

Molecular simulation study of self-assembly of tethered V-shaped nanoparticles.

We use Brownian dynamics to investigate the self-assembly of single end tethered, laterally tethered, and double end tethered V-shaped nanoparticles. The simulation results are compared with model bent-core molecules without tethers and polymer tethered nanorods to elucidate the combined effects of V-shaped geometry and the immiscibility between the V-shaped nanoparticles and the tethers on the self-assembled structures. We show that the V-shaped geometry significantly alters the phase diagram of tethered nanoparticles and further that the immiscibility between particles and tethers leads to structures not previously predicted for bent-core molecules.

Simulations and analysis of self-assembly of CdTe nanoparticles into wires and sheets.

Recent experiments have reported the self-assembly of TGA- and DMAET-stabilized CdTe nanoparticles (NPs) into wires and sheets, respectively, depending upon the stabilizer used. We develop a mesoscale model based on quantum mechanical calculations and perform Monte Carlo simulations of these NPs to elucidate the conditions under which these two structures will form. We show that consideration of NP shape, directional attraction, and electrostatic interactions is key to determining the anisotropy of the NP-NP interaction and final self-assembled structures.

Simulation studies of the self-assembly of cone-shaped particles.

We investigate the self-assembly of anisotropic cone-shaped particles decorated by ringlike attractive "patches". In a recent paper, we demonstrated that the self-assembled clusters, which arise due to the conical particle's anisotropic shape combined with directional attractive interactions, are precise for certain cluster sizes, resulting in a precise packing sequence of clusters of increasing sizes with decreasing cone angles (Chen et al. Proc.

A precise packing sequence for self-assembled convex structures.

Molecular simulations of the self-assembly of cone-shaped particles with specific, attractive interactions are performed. Upon cooling from random initial conditions, we find that the cones self-assemble into clusters and that clusters comprised of particular numbers of cones (e.g.

Simulation studies of self-assembly of end-tethered nanorods in solution and role of rod aspect ratio and tether length.

We present temperature versus concentration phase diagrams for "shape amphiphiles" comprised of tethered moderate and low aspect ratio rods. Simulations of moderate aspect ratio rods (first reported by Horsch et al. [Phys.

Self-assembly of laterally-tethered nanorods.

We report results from a computational study of laterally tethered nanorod "shape amphiphiles". Our simulations predict that the model nanorods self-assemble into stepped-ribbon-like micelles, a centered rectangular stepped-ribbon phase, and two structurally different liquid crystalline bilayer phases: one in which the bilayers have C(mm) symmetry and another in which they have P(2) symmetry. We provide a possible explanation for the transition between the two C(mm) and P(2) liquid crystalline phases.

Self-assembly of CdTe nanocrystals into free-floating sheets.

In their physical dimensions, surface chemistry, and degree of anisotropic interactions in solution, CdTe nanoparticles are similar to proteins. We experimentally observed their spontaneous, template-free organization into free-floating particulate sheets, which resemble the assembly of surface layer (S-layer) proteins. Computer simulation and concurrent experiments demonstrated that the dipole moment, small positive charge, and directional hydrophobic attraction are the driving forces for the self-organization process.

Self-assembly of patchy particles into diamond structures through molecular mimicry.

Fabrication of diamond structures by self-assembly is a fundamental challenge in making three-dimensional photonic crystals. We simulate a system of model hard particles with attractive patches and show that they can self-assemble into a diamond structure from an initially disordered state. We quantify the extent to which the formation of the diamond structure can be facilitated by "seeding" the system with small diamond crystallites or by introducing a rotation interaction to mimic a carbon-carbon antibonding interaction.

Phase diagrams of self-assembled mono-tethered nanospheres from molecular simulation and comparison to surfactants.

We perform Brownian dynamics simulations on model 3-D systems of mono-tethered nanospheres (TNS) to study the equilibrium morphologies formed by their self-assembly in a selective solvent. We predict that in contrast to flexible amphiphiles the nanospheres are locally ordered and there is an increase in the local order with an increase in concentration or relative nanoparticle diameter. We present the temperature vs concentration phase diagram for a system of TNS and propose a dimensionless scaling factor F(v) (headgroup volume/tether volume) that allows a comparison between the morphologies formed from TNS and traditional surfactants.

Self-assembly of polymer-tethered nanorods.

We present results of molecular simulations that predict the phases formed by self-assembly of nanorods functionalized by a polymer "tether." Microphase separation of the immiscible tethers and rods coupled with the liquid crystal ordering of the rods induces the formation of a cubic phase, a smectic C phase, a tetragonally perforated lamellar phase, and a honeycomb phase; the latter two have been observed experimentally but have not been predicted. We also predict a new phase--a racemic mixture of hexagonally ordered chiral cylinders that self-assemble from these achiral building blocks.

Hydrodynamics and microphase ordering in block copolymers: are hydrodynamics required for ordered phases with periodicity in more than one dimension?

We use Brownian dynamics (BD), molecular dynamics, and dissipative particle dynamics to study the phase behavior of diblock copolymer melts and to determine if hydrodynamics is required in the formation of phases with greater than one-dimensional periodicity. We present a phase diagram for diblock copolymers predicted by BD and provide a relationship between the inverse dimensionless temperature epsilon/k(B)T and the Flory-Huggins chi parameter, allowing for a quantitative comparison between methods and to mean field predictions. Our results concerning phase behavior are in good qualitative agreement with the theoretical predictions of Matsen and Bates [M.