A Molecular CO Reduction Catalyst Based on Giant Polyoxometalate {Mo}.

Photocatalytic CO reduction in water is one of the most attractive research pursuits of our time. In this article we report a giant polyoxometalate {Mo} based homogeneous catalytic system, which efficiently reduces CO to formic acid with a maximum turnover number (TON) of 27,666, turnover frequency (TOF) of 4,611 h and external quantum efficiency of the reaction is 0.6%.

A direct DRS-FTIR probe for rapid detection and quantification of fluoroquinolone antibiotics in poultry egg-yolk.

We report a novel diffuse reflectance-Fourier transforms infrared (DRS-FTIR) spectral monitoring of fluoroquinolone antibiotics such as ciprofloxacin (CIP) and norfloxacin (NOR) for their quantification in poultry egg-yolks. To the best of our knowledge, this is the first report to describe the rapid quantitative determination of fluoroquinolone antibiotics in poultry egg samples using DRS-FTIR. The characteristic absorption peaks obtained at 1627 and 1026 cm were used for optimization and determination of CIP and NOR, respectively.

Phosphatase-like Activity of Tetranuclear Iron(III) and Zinc(II) Complexes.

Three new tetranuclear iron(III) and zinc(II) complexes, [Fe(cpdp)(phth)(OH)]·8HO (1), [Fe(cpdp)(terephth)(OH)] (2), and [Zn(Hcpdp)(suc)]Br·12HO (3), have been synthesized as models for the active site of phosphoester hydrolases by utilizing a polydentate ligand, N, N'-bis[2-carboxybenzomethyl]- N, N'-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol (Hcpdp) in combination with exogeneous phthalate (phth), terephthalate (terephth), and succinate (suc). Single crystal X-ray analyses reveal that the metallic core of complex 1 consists of four distorted octahedral iron(III) ions with average intraligand Fe---Fe separation of 3.656(2) Å, while the structure 3 represents a tetranuclear metallic core containing four distorted trigonal bipyramidal zinc(II) ions with average intraligand Zn---Zn separation of 3.

Stable and scalable 1T MoS with low temperature-coefficient of resistance.

Monolithic realization of metallic 1T and semiconducting 2H phases makes MoS a potential candidate for future microelectronic circuits. A method for engineering a stable 1T phase from the 2H phase in a scalable manner and an in-depth electrical characterization of the 1T phase is wanting at large. Here we demonstrate a controllable and scalable 2H to 1T phase engineering technique for MoS using microwave plasma.

Interaction of arsenic with gap junction protein connexin 43 alters gap junctional intercellular communication.

Chronic exposure to Arsenic pollution in ground water is one of the largest environmental health disasters in the world. The toxicity of trivalent Arsenicals primarily happens due to its interaction with sulfhydryl groups in proteins. Arsenic binding to the protein can change the conformation of the protein and alter its interactions with other proteins leading to tissue damage.

Surface Electronic States Induced High Terahertz Conductivity of CoO Microhollow Structure.

Herein, we report the observation of unusual electronic and magnetic phases in traditional antiferromagnetic CoO micromaterials and modulation of their properties on a temperature scale. In particular, we demonstrate a comparative low-energy carrier dynamics of CoO microflower and microhollow flower (MHF) structures of same average size of 2 μm to unravel the ground-state information induced by surface electronics across the insulator-semiconductor transition using terahertz (THz) time domain spectroscopy. Interestingly, the THz optical constants of these structures are found to exhibit remarkably distinct features both as a function of frequency and temperature.

[1+1+3] Annulation of Diazoenals and Vinyl Azides: Direct Synthesis of Functionalized 1-Pyrrolines through Olefination.

A dirhodium carboxylate catalyzed [1+1+3] annulation reaction of diazoenals and vinyl azides that gives synthetically important enal-functionalized 1-pyrroline derivatives was developed. The reaction involves a novel rhodium-catalyzed olefination of diazoenals with vinyl azides via electrophilic enal carbenoids, resulting in a new class of enal acrylates. The annulation reaction was used for the direct synthesis of valuable deuterated 1-pyrrolines.

H, C and N resonance assignment of domain 1 of trans-activation response element (TAR) RNA binding protein isoform 1 (TRBP2) and its comparison with that of isoform 2 (TRBP1).

TAR RNA binding protein (TRBP) is a double-stranded RNA binding protein involved in various biological processes like cell growth, development, death, etc. The protein exists as two isoforms TRBP2 and TRBP1. TRBP2 contains additional 21 amino acids at its N-terminus, which are proposed to be involved in its membrane localization, when compared to TRBP1.

A review on suppression and utilization of the coffee-ring effect.

Evaporation of sessile droplets containing non-volatile solutes dispersed in a volatile solvent leaves behind ring-like solid stains. As the volatile species evaporates, pinning of the contact line gives rise to capillary flows that transport non-volatile solutes to the contact line. This phenomenon, called the coffee-ring effect, compromises the overall performance of industrially relevant manufacturing processes involving evaporation such as printing, biochemical analysis, manufacturing of nano-structured materials through colloidal and macromolecular patterning.

Evolution of the metabolome in response to selection for increased immunity in populations of Drosophila melanogaster.

We used NMR-based metabolomics to test two hypotheses-(i) there will be evolved differences in the metabolome of selected and control populations even under un-infected conditions and (ii) post infection, the metabolomes of the selected and control populations will respond differently. We selected replicate populations of Drosophila melanogaster for increased survivorship (I) against a gram-negative pathogen. We subjected the selected (I) and their control populations (S) to three different treatments: (1) infected with heat-killed bacteria (i), (2) sham infected (s), and (3) untreated (u).

Temperature dependent polymorphism of pyrazinamide: An in situ Raman and DFT study.

The α and γ polymorphs of drug pyrazinamide have been detected with the help of temperature dependent Raman spectroscopic technique. Pyrazinamide is a very useful drug used for the treatment of tuberculosis (TB) and plays a significant role in destroying the dormant tubercle bacilli which are not destroyed by other common TB drugs. Temperature dependent Raman spectra suggest polymorphic phase change from α→γ form of pyrazinamide between 145 and 146°C.

Softoxometalate [{KCu(OH)(HO)}@{KPWO}] (n = 1348-2024) as an Efficient Inorganic Material for CO Reduction with Concomitant Water Oxidation.

An immediate challenge for chemists is to devise different methods to trap chemical energy using light by reduction of carbon dioxide to a transportable fuel. To reach this goal the major obstacle lies in finding a suitable material that is abundant and possesses catalytic power to effect such reduction reaction and perform this reduction reaction without using any external photosensitizer. Here we report for the first time a softoxometalate based on a {[KCu(OH)(HO)][KPWO]} metal oxide framework which is stable in reaction conditions that effectively performs photochemical CO reduction reaction in water with a very high turnover number of 613 and TOF of 47.

Conformational Landscape of Tri-n-butyl Phosphate: Matrix Isolation Infrared Spectroscopy and Systematic Computational Analysis.

The conformations of tri-n-butyl phosphate (TBP) were studied using matrix isolation infrared spectroscopy and density functional theory (DFT) calculations. TBP was trapped in a N matrix using both effusive and supersonic sources, and its infrared spectra were recorded. The computational exploration of TBP is a very demanding problem to confront, due to the presence of a large multitude of conformations in TBP.

The borazine dimer: the case of a dihydrogen bond competing with a classical hydrogen bond.

Dimers of borazine were studied using matrix isolation infrared spectroscopy and ab initio quantum chemical calculations. Computations were performed at the MP2 and M06-2X levels of theory using the 6-311++G(d,p) and aug-cc-pVDZ basis sets for the various homodimers. At both levels of theory, an aligned stacked structure was found to be the global minimum, which was nearly isoenergetic to a parallel displaced structure.

Redox regulation of the yeast voltage-gated Ca channel homolog Cch1p by glutathionylation of specific cysteine residues.

Cch1p, the yeast homolog of the pore-forming subunit α of the mammalian voltage-gated Ca channel (VGCC), is located on the plasma membrane and mediates the redox-dependent influx of Ca Cch1p is known to undergo both rapid activation (after oxidative stress and or a change to high pH) and slow activation (after ER stress and mating pheromone activation), but the mechanism of activation is not known. We demonstrate here that both the fast activation (exposure to pH 8-8.5 or treatment with HO) and the slow activation (treatment with tunicamycin or α-factor) are mediated through a common redox-dependent mechanism.

Inorganic Phosphate and Arsenate within New Tetranuclear Copper and Zinc Complexes: Syntheses, Crystal Structures, Magnetic, Electrochemical, and Thermal Studies.

Three, PO /HPO and AsO -incorporated, new tetranuclear complexes of copper(II) and zinc(II) ions have been synthesized and fully characterized. In methanol-water, reactions of Hcpdp (Hcpdp = ,'-Bis[2-carboxybenzomethyl]-,'-Bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol) with copper(II) chloride in the presence of either NaOH/NaHPO·2HO or KOH/NaHAsO·7HO lead to the isolation of the tetranuclear complexes Na[Cu(cpdp)(μ-PO)](OH)·14HO () and K[Cu(cpdp)(μ-AsO)](OH)·16/HO (), respectively. Similarly, the reaction of Hcpdp with zinc(II) chloride in the presence of NaOH/NaHPO·2HO yields a tetranuclear complex, Na(HO)[Zn(cpdp)(μ-HPO)]Cl·12/HO ().

Novel Glycopyrrolidine Compounds Inhibit Human Cancer Cell Proliferation and Induce Apoptotic Mode of Cell Death.

Spirocyclic compounds, present in a number of bioactive natural alkaloids, are cyclic systems containing one carbon atom common to two rings. A highly regioselective glycopyrrolidine compound library was synthesized using 1,3-dipolar cycloaddition method, and its efficacy was tested on cell lines representing most commonly occurring cancers and the molecular mechanism of cell death deciphered. Results showed that among the 16 compounds screened, RPRR210 showed the most potent anticancer activity and induced cell cycle arrest, inhibited migration, caused cell death by inducing apoptosis through the intrinsic pathway, and were nontoxic to normal cells.

Enzyme activity of α-chymotrypsin: Deactivation by gold nano-cluster and reactivation by glutathione.

Effect of gold nanoclusters (Au-NCs) on the circular dichroism (CD) spectra and enzymatic activity of α-chymotrypsin (ChT) (towards hydrolysis of a substrate, N-succinyl-l-phenylalanine p-nitroanilide) are studied. The CD spectra indicate that on binding to Au-NC, ChT is completely unfolded, resulting in nearly zero ellipticity. α-chymotrypsin (ChT) coated gold nano-clusters exhibit almost no enzymatic activity.

A Gap Junction Protein, Inx2, Modulates Calcium Flux to Specify Border Cell Fate during Drosophila oogenesis.

Intercellular communication mediated by gap junction (GJ) proteins is indispensable during embryogenesis, tissue regeneration and wound healing. Here we report functional analysis of a gap junction protein, Innexin 2 (Inx2), in cell type specification during Drosophila oogenesis. Our data reveal a novel involvement of Inx2 in the specification of Border Cells (BCs), a migratory cell type, whose identity is determined by the cell autonomous STAT activity.

Scale-dependent diffusion anisotropy in nanoporous silicon.

Nanoporous silicon produced by electrochemical etching of highly B-doped p-type silicon wafers can be prepared with tubular pores imbedded in a silicon matrix. Such materials have found many technological applications and provide a useful model system for studying phase transitions under confinement. This paper reports a joint experimental and simulation study of diffusion in such materials, covering displacements from molecular dimensions up to tens of micrometers with carefully selected probe molecules.

Uncoupling of an ammonia channel as a mechanism of allosteric inhibition in anthranilate synthase of Serratia marcescens: dynamic and graph theoretical analysis.

Anthranilate synthase (AS) is the first branch node enzyme that catalyzes the conversion of chorismate to anthranilate in the high energy-consuming tryptophan biosynthetic pathway in Serratia marcescens. AS, with an allosterically-bound inhibitor (tryptophan), shows complete inhibition in its catalytic function, but the inhibitor-bound structure is very similar to that of the substrate-bound AS. Even though the reaction mechanisms of several chorismate-utilizing enzymes are known, the unusual structure-function relationship in catalysis and allosteric inhibition of AS by tryptophan, with an insignificant change in structure, remains elusive.