新型二氧代氮杂茂并[3′,4′-d]异噁唑衍生物的合成

在三乙胺作用下,N-取代苯基马来酰亚胺与α-氯代对甲氧基苯甲醛肟发生1,3-偶极环加成反应,合成了6个新型3-(对甲氧基苯基)-5-芳基-3a,6a-二氢-4,6-二氧代氮杂茂并[3′,4′-d]异噁唑衍生物,其结构经1HNMR,IR和元素分析确证。     

Complex‐radical terpolymerization of acceptor–donor–acceptor systems: Maleic anhydride (n‐butyl methacrylate)–styrene–acrylonitrile

Some features of radical ternary copolymerization of maleic anhydride (MA)–styrene (St)–acrylonitrile (AN) and n‐butyl methacrylate (BMA)–St–AN acceptor–donor–acceptor monomer systems have been revealed. The terpolymer compositions and kinetics of copolymerizations were studied in the initial and high conversion stages. The considerable divergence in the copolymer compositions was observed when a strong acceptor MA monomer was substituted with BMA having comparatively low acceptor character in the ternary system studied. Obtained results show that terpolymerization proceeded mainly through “complex” mechanism in the state of near binary copolymerization of St…MA (or BMA) and AN…St complexes only in the chosen ratios of complexed monomers. The terpolymers synthesized have high thermal stabilities (295–325 °C), which is explained by possible intermolecular fragmentation of AN‐units through cyclization and crosslinking reactions during thermotreatment in the isothermal heating conditions. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2652–2662, 2000     

Syntheses,characterizations, crystal structures,DFT/TD-DFT,luminescence behaviors and cytotoxic effect of bicompartmental Zn (II)-dicyanamide Schiff base coordination polymers: An approach to apoptosis,autophagy and necrosis type classical cell death

Two new Zn (II)-dicyanamide (dca) 1-D chain coordination polymers (CPs), [Zn (L^OMe)(μ₁-dca)(μ_1,5-dca)]_n (1) and [Zn (L^OEt)(μ₁-dca)(μ_1,5-dca)]_n (2) have been successfully synthesized from bicompartmental Schiff base ligands N,N^′-Bis(3-methoxysalicylidenimino)-1,3-diaminopropane (H₂L^OMe), N,N^′-Bis(3-ethoxysalicylidenimino)-1,3-diaminoproane (H₂L^OEt) respectively and structurally characterized using various spectroscopic protocols like ¹H NMR, IR, Raman, UV–Vis, fluorescence as well as elemental analysis, TGA, PXRD and SCXRD studies. X-ray single crystal study revealed that both the complexes have two different geometrical arrangement of Zn metal centres with distorted square pyramidal Zn(2) and trigonal prismatic geometry Zn(1). Ab-initio DFT (Density functional theory) has been executed at B3LYP (Becke, 3-parameter, Lee-Yang-Parr) using DGDVP (Diffuse gradient double valence polarised) basis set to explain FMO (Frontier molecular orbital), TD-DFT (Time-dependent density functional theory) and photovoltaic efficiency in Dye Sensitized Solar Cell (DSSC). Hirshfeld surface (HS) and 2D fingerprint plot analyses are shed more light on the non-covalent supramolecular interactions. The steady state and time-resolved fluorescence measurements have been conducted in DMSO and solid-state. CPs exhibited bi-exponential decay in DMSO as well as solid-state where fluorescence behaviors are mainly intra-ligand (π → π^*) in nature with lifetimes in the range (1.11–1.06 ns). In particular, in vitro cytotoxic activities were evaluated towards MCF7 (breast cancer) cell line, MDA-MB-231 (breast carcinoma) cell line and MCF10A (breast epithelial) cell line using MTT assay. CP 1 had lower cytotoxic effect against MCF7 (20 μM), MDA-MB-231 (15 μM) cell lines in comparison with cisplatin (42.2 ± 8, 128.2 ± 7 μM). CP 1 induced classical cell death apoptosis, autophagy and necrosis. Lower IC₅₀ value of CP 1 against MDA-MB-231 cell line provide new insights in the development of cancer therapeutics.     

Dust ion acoustic waves in non-thermal Cairns bi-Maxwellian plasma

Using kinetic theory approach, the dispersion relation ω_r and Landau damping rate γ for dust ion acoustic waves are investigated numerically and analytically in an unmagnetized collisionless dusty plasma considering Cairns distribution for electrons and ions in stationary dust particles background. The phase velocity and Landau damping rate are calculated in the limits v_td∥ < v_ti∥ << ω/k << v_te∥ . The electrons and ions non-thermality effects are incorporated via the non-thermality parameter (0 ≤ α < 1) . The real frequency ω_r and Landau damping rate γ of the mode in Cairns bi-Maxwellian distributed plasma are graphically shown to depend on plasma parameters namely non-thermality index α , ion to electron temperature ratio T_i∥/T_e∥ and the dust concentration parameter δ (=1 − ηZ_d) .     

Functional copolymer/organo‐MMT nanoarchitectures. VII. Interlamellar controlled/living radical copolymerization of maleic anhydride with butyl methacrylate via preintercalated RAFT agent–organoclay complexes

We have developed a new approach for the synthesis of polymer nanocomposites using a bifunctional reversible addition–fragmentation chain transfer (RAFT) agent, two types of organo‐montmorillonites (O‐MMT), such as a non‐reactive dimethyldidodecyl ammonium (DMDA)‐MMT and a reactive octadecyl amine (ODA)‐MMT organoclays, maleic anhydride (MA), and n‐butyl methacrylate (BMA) monomers and a radical initiator. This method includes the following stages: (1) synthesis of RAFT intercalated O‐MMTs by a physical or chemical interaction of the RAFT agent having two pendant carboxylic groups [S,S′‐bis(α,α′‐dimethyl‐α″‐acetic acid) trithiocarbonate] with surface alkyl amines of O‐MMT containing tertiary ammonium cation or primary amine groups through strong H‐bonding and compexing/amidization reactions, respectively, and (2) utilization of these well dispersed and intercalated RAFT…O‐MMT complexes and amide derivative of RAFT…ODA‐MMT as new modified RAFT agents in radical‐initiated interlamellar controlled/living complex‐radical copolymerization of MA‐BMA monomer pair. Nanostructure and compositions of the synthesized RAFT…O‐MMT complexes and functional copolymer/O‐MMT hybrids were confirmed by FTIR, GPC, XRD, thermal (DSC‐TGA), SEM, and TEM morphology analyses. This simple and versatile method can be applied to a wide range of monomer/comonomer systems for the preparation of completely exfoliated macromolecular nanoarchitectures. Copyright © 2011 John Wiley & Sons, Ltd.     

Model discrimination using data collaboration

This paper introduces a practical data-driven method to discriminate among large-scale kinetic reaction models. The approach centers around a computable measure of model/data mismatch. We introduce two provably convergent algorithms that were developed to accommodate large ranges of uncertainty in the model parameters. The algorithms are demonstrated on a simple toy example and a methane combustion model with more than 100 uncertain parameters. They are subsequently used to discriminate between two models for a contemporarily studied biological signaling network.     

Structural disorder of the CD3zeta transmembrane domain studied with 2D IR spectroscopy and molecular dynamics simulations

In a recently reported study [Mukherjee, et al. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 3528] we used 2D IR spectroscopy and 1-(13)C=(18)O isotope labeling to measure the vibrational dynamics of 11 amide I modes in the CD3zeta transmembrane domain. We found that the homogeneous line widths and population relaxation times were all nearly identical, but that the amount of inhomogeneous broadening correlated with the position of the amide group inside the membrane. In this study, we use molecular dynamics simulations to investigate the structural and dynamical origins of these experimental observations. We use two models to convert the simulations to frequency trajectories from which the mean frequencies, standard deviations, frequency correlation functions, and 2D IR spectra are calculated. Model 1 correlates the hydrogen-bond length to the amide I frequency, whereas model 2 uses an ab initio-based electrostatic model. We find that the structural distributions of the peptidic groups and their environment are reflected in the vibrational dynamics of the amide I modes. Environmental forces from the water and lipid headgroups partially denature the helices, shifting the infrared frequencies and creating larger inhomogeneous distributions for residues near the ends. The least inhomogeneously broadened residues are those located in the middle of the membrane where environmental electrostatic forces are weakest and the helices are most ordered. Comparison of the simulations to experiment confirms that the amide I modes near the C-terminal are larger than at the N-terminal because of the asymmetric structure of the peptide bundle in the membrane. The comparison also reveals that residues at a kink in the alpha-helices have broader line widths than more helical parts of the peptide because the peptide backbone at the kink exhibits a larger amount of structural disorder. Taken together, the simulations and experiments reveal that infrared line shapes are sensitive probes of membrane protein structural and environmental heterogeneity.     

A novel dual surface modification on titanium in dental use: Characterization and topography

This laboratory study aimed to compare, contrast, and evaluate the effect of a novel dual surface modification method on the adhesion strength of resin composite cement to titanium. C.p.-2 grade titanium samples were silica-coated, etched with HNO₃(69vol %) or a blend of HCl (35vol %) and H₃PO₄ (85vol %), for 1 h at 80°C. Surface roughness was measured by surface roughness profilometry, topographic analysis by scanning electron microscopy (SEM), atomic force microscopy (AFM), and surface analyses by energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS). Silanization of all specimens was carried out after SEM, EDX, and AFM analysis, before enclosed mold microshear bond strength testing (EM-μSBS). Adhesion strengths were measured after artificial ageing: 1 day, 1 week, 4 weeks, and 8 weeks by EM-μSBS testing and failure mode analysis by optical microscopy. Polished titanium was used as a control. The highest surface roughness was observed in titanium samples treated with silica-coating + HCl-H₃PO₄ etching. The elemental composition confirmed the presence of Ti, O, C, with Si and Al in samples treated with silica-coating. A gradual decrease in EM-μSBS values was observed in all titanium samples with adhesive and cohesive failure modes. The novel dual surface modification method applied in this study suggests that silica-coating + HCl-H₃PO₄etching strongly affects titanium surface topography and roughness. The presence of Si on silica-coated surface modified titanium before silanization with an experimental silane has a positive effect on the EM-μSBS of titanium samples treated with silica-coating only or silica-coating + HNO₃ etching.     

Thermodynamic study of antimony chalcoiodides by EMF method with an ionic liquid

Journal of Thermal Analysis and Calorimetry - A combination of sol–gel Pechini method and flame synthesis was used to prepare yttrium aluminate glass microspheres with the garnet composition...     

Microfluidic fluorescence in situ hybridization and flow cytometry (μFlowFISH)

We describe an integrated microfluidic device (μFlowFISH) capable of performing 16S rRNA fluorescence in situ hybridization (FISH) followed by flow cytometric detection for identifying bacteria in natural microbial communities. The device was used for detection of species involved in bioremediation of Cr(vi) and other metals in groundwater samples from a highly-contaminated environmental site (Hanford, WA, USA). The μFlowFISH seamlessly integrates two components: a hybridization chamber formed between two photopolymerized membranes, where cells and probes are electrophoretically loaded, incubated and washed, and a downstream cross structure for electrokinetically focusing cells into a single-file flow for flow cytometry analysis. The device is capable of analyzing a wide variety of bacteria including aerobic, facultative and anaerobic bacteria and was initially tested and validated using cultured microbes, including Escherichia coli, as well as two strains isolated from Hanford site: Desulfovibrio vulgaris strain RCH1, and Pseudomonas sp.strain RCH2 that are involved in Cr(vi) reduction and immobilization. Combined labeling and detection efficiencies of 74-97% were observed in experiments with simple mixtures of cultured cells, confirming specific labeling. Results obtained were in excellent agreement with those obtained by conventional flow cytometry confirming the accuracy of μFlowFISH. Finally, the device was used for analyzing water samples collected on different dates from the Hanford site. We were able to monitor the numbers of Pseudomonas sp. with only 100-200 cells loaded into the microchip. The μFlowFISH approach provides an automated platform for quantitative detection of microbial cells from complex samples, and is ideally suited for analysis of precious samples with low cell numbers such as those found at extreme environmental niches, bioremediation sites, and the human microbiome.