The synthesis, structure, topology and catalytic application of a novel cubane-based copper(II) metal-organic framework derived from a flexible amido tripodal acid

A novel chiral metal-organic framework, [Cu-4(HL)(2)(H2O)(4)(MeO)(4)](n) (1), has been successfully synthesized from a tripodal flexible ligand (2S, 2'S, 2 '' S)- 2,2', 2 ''-(benzenetricarbonyltris(azanediyl)) tripropanoic acid (H3L). Compound 1 was characterized by IR and X-ray powder diffraction analysis. The structure was determined by X-ray single crystal diffraction analysis revealing that 1 possesses a 3D network, featuring a tetranuclear cubane-type secondary building block [Cu-4(MeO)(4)](4+), formed via the connection of four metal ions to four methoxide ions. These secondary building blocks are linked by four different HL2- ligands to construct a porous three dimensional framework of the dia topology with one-dimensional channels. Compound 1 also acts as a heterogeneous catalyst for the diastereoselective nitroaldol (Henry) reaction, providing high yields (up to 91%) and good diastereoselectivities under ambient conditions. This catalyst can be recycled without significant loss of activity

Salt Crystal Growth in Interacting Drops of a Complex Biopolymer: Statistical Characterization Using FESEM Images

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.  A simple colloidal drop generally forms ring like patterns after drying. The deposition morphology of the dried drop changes significantly when such a drop dries in the vicinity of another similar drop. Here we present an observational study and statistical analysis of the patterns formed inside an isolated as well as interacting drops of gelatin containing sodium sulfate (Na2SO4). In all the cases, multiple concentric regions of solute particles combined with the polymer gel appear as the drops dry up. Needle crystals of sulfur and coacervates of salt and gelatin are visible in some regions. The outer region becomes non-uniform, so does the size distribution of the needle crystals and coacervates. The non-uniformity increases with proximity of the drops. Here we propose a novel mechanism of growing patterns inside the single drop during drying and correlate that with the results obtained for interacting drops. This study and the proposed mechanism provide insights into the future studies of drying drops under different physical conditions. Further we explore the statistical characteristics of the single and interacting drops using the field emission scanning electron microscopy (FESEM) images. Next, we report fractal and image texture analyses along with object shape statistics of the drop FESEM images, under various experimental conditions. Several statistical hypothesis tests have been carried out to identify the most significant features.SERB, IndiaGovt. of Indi

Prevalence of gastro-intestinal symptoms during pregnancy: a questionnaire based study in a tertiary care center of South Asia

Background: Gastrointestinal symptoms lead to morbidity in pregnancy, yet remain a surprisingly under-researched topic. The objective was to find out the prevalence of various gastro-intestinal symptoms in pregnant women, the status before pregnancy, and their perceived impact.Methods: A questionnaire incorporating various gastro-intestinal problems was prepared and used over 184 pregnant women to know their prevalence in different trimesters of pregnancy and compare them with prevalence before pregnancy. 184 matched non-pregnant women were also interrogated as additional control group.Results: Constipation was seen significantly more often during pregnancy (24.5%) and was maximum in the first trimester (31.8%) followed by third trimester (26.3%) and second trimester (19.0%) as compared to only 9.8% of women in non-pregnant state. Diarrhea was also more rampant in pregnancy (9.2%), especially in third trimester (13.1%) than before pregnancy (1.6%). Constipation, diarrhea and fecal incontinence were much commoner in pregnant as compared to non-pregnant controls.Conclusions: There is a very high prevalence of gastro-intestinal symptoms during pregnancy as compared to non-pregnant state. More studies are needed to highlight the Quality-Of-Life issues with these symptoms

Defects induced ferromagnetism in Mn doped ZnO

Single phase Mn doped (2 at %) ZnO samples have been synthesized by solid-state reaction technique. Before the final sintering at 500 C, the mixed powders have been milled for different milling periods (6, 24, 48 and 96 hours). The grain sizes of the samples are very close to each other (~ 32 \pm 4 nm). However, the defective state of the samples is different from each other as manifested from the variation of magnetic properties and electrical resistivity with milling time. All the samples have been found to be ferromagnetic with clear hysteresis loops at room temperature. The maximum value for saturation magnetization (0.11 {\mu}_B / Mn atom) was achieved for 96 hours milled sample. Electrical resistivity has been found to increase with increasing milling time. The most resistive sample bears the largest saturation magnetization. Variation of average positron lifetime with milling time bears a close similarity with that of the saturation magnetization. This indicates the key role played by open volume vacancy defects, presumably zinc vacancies near grain surfaces, in inducing ferromagnetic order in Mn doped ZnO. To attain optimum defect configuration favorable for ferromagnetism in this kind of samples proper choice of milling period and annealing conditions is required.Comment: Accepted in Journal of Magnetism and Magnetic Material

Identification and optimization of small molecule antagonists of vasoactive intestinal peptide receptor-1 (VIPR1)

Identification, synthesis and structure-activity relationship of small-molecule VIPR1 antagonists encompassing two chemical series are described

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum