A New Sodium Borate: Na[B6O8(OH)3]·6H2O·H3BO3

The structure of [B₆H₉NaO₁₄, H₃BO₃, 6H₂O] was determined by single‐crystal X‐ray diffraction and further analyzed by FTIR spectroscopy and differential thermal/thermogravimetric analysis. The asymmetric unit contains Na–O polyhedra (distorted octahedron), [B₆O₈(OH)₃]^– fundamental building blocks, one free water molecule and one free H₃BO₃ molecule. In the hexaborate anion, three B₃O₃ rings are linked by a common oxygen atom with five trigonal and one tetrahedral boron atoms. The hexaborate group is also linked to the oxygenated environment of the sodium atom by three other six‐membered rings, each of which involve two boron atoms, three oxygen atoms, and sodium as the joint atom.     

Oxidative Dearomatization: Synthesis of Functionalized Bicyclo[2.2.2]octenones,Sigmatropic Shift in Excited State,and Radical-Induced Cleavage of Cyclopropane Ring

Synthesis of novel bicyclo[2.2.2]octenones endowed with a β,γ-enone system in which γ-carbon is substituted with an electron-withdrawing group from simple aromatics is described. Oxa-di-pi-methane reaction of bicyclo[2.2.2]octenones to functionalized bicyclo[3.3.0]octanes and their transformation to bicyclo[3.2.1]octane framework are also presented.     

Thermalization and temperature reached in heavy-ion collision using the isospin-dependent quantum molecular dynamics model

One-neutron knockout reactions in a ⁹Be target have been investigated at relativistic energies, near 700 MeV/u, for a set of sd-shell, neutron-rich nuclei. The experiment was performed in the FRS spectrometer, at GSI. ??-ray measurements were carried out by means of the MINIBALL ??-ray spectrometer and allowed the determination of partial cross-sections and branching ratios corresponding to the final states of the emerging knockout fragments. Experimental results are presented for ¹⁷C, ¹⁹N, ²¹O and ²⁵F projectiles. The role of excited states of the N ? 1 fragments in the composition of the ground state of these neutron-rich projectiles is outlined in this work.     

Microwave-assisted Vilsmeier-Haack synthesis of Pyrazole-4-carbaldehydes

The synthesis of 4-formylpyrazoles using Vilsmeier-Haack reagent is a common protocol in pyrazole chemistry. An efficient microwave-assisted synthesis of 4-formylpyrazoles by employing Vilsmeier-Haack reagent (OPC-VH) derived from phthaloyl dichloride/dimethylformamide has been described. This method offers the advantages of operational simplicity, avoiding the use of POCl₃ as toxic reagents and reuse of the by-product in the preparation of phthaloyl dichloride.     

A Rapid Densitometric TLC Method for Simultaneous Analysis of Costunolide and Dehydrocostus Lactone in Saussurea Costus

Costunolide and dehydrocostus lactone are two guianolide sesquiterpene lactones present in abundance in Saussurea costus, a plant popularly known as `costus' and renowned throughout the world for its medicinal properties. A simple densitometric TLC method for simultaneous quantification of costunolide and dehydrocostus lactone, without derivatization, has been developed as an alternative to gas chromatography. The method enables rapid, sensitive, and reproducible simultaneous analysis of a variety of samples. The method was validated for precision, repeatability, and accuracy in accordance with ICH guidelines. Amounts of costunolide and dehydrocostus lactone in different samples of costus, estimated by use of this method, were in the range 0.46 to 1.00% and 0.81 to 1.21%, respectively. The proposed method is simple, precise, specific, sensitive, and accurate and can be used by the herbal drug industry for routine quality control of the crude drug costus.     

Electrochemically generated tungsten‐based active species as catalysts for metathesis‐related reactions: 2. Ring‐opening metathesis polymerization of norbornene

The present work reports the application of the WCl₆–e^?–Al–CH₂Cl₂ catalyst system to the ring‐opening metathesis polymerization of norbornene. Analysis of the polynorbornene microstructure by means of ¹H and ¹³C NMR spectroscopy indicates that the polymer contains a mainly cis stereoconfiguration of the double bonds (σ_c = 0.61) and a blocky distribution (r_tr_c > 1) of cis and trans double bonds (r_tr_c = 3.37). This catalytic system is reluctant to facilitate the competing addition reactions of cycloalkenes while proceeding with the polymerization reactions with good conversions and at short periods. Copyright © 2004 John Wiley & Sons, Ltd.     

Magnetic proximity effect in the topological insulator BiSbTeSe2

Magnetic proximity effects can lead to novel phenomena in the transport properties of topological insulators. In this study, we demonstrate a characteristic fourfold symmetry in the angular dependence of magnetoresistance in the topological insulator BiSbTeSe₂ exfoliated onto magnetic insulator yttrium iron garnet substrates. The observed symmetry is seen to arise when the external magnetic field is in‐plane to the current direction and gets enhanced at large field magnitudes. Increasing the temperature and current density diminishes the fourfold symmetry. The symmetry seems to be a signature of the proximity effect from the underlying magnetic substrate on BiSbTeSe₂. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Spin–lattice relaxation phenomena in the magnetic state of a suggested Weyl semimetal CeAlGe

ABSTRACT

In this work, we report the results of DC susceptibility, AC susceptibility and related technique, resistivity, transverse and longitudinal magnetoresistance and heat capacity on polycrystalline magnetic semimetal CeAlGe. This compound undergoes antiferromagnetic type ordering around 5.2 K (T¹). Under the application of external magnetic fields, parallel alignment of magnetic moments is favoured above 0.5?T. At low field and temperature, frequency and AC field amplitude response of AC susceptibility indicate the presence of spin–lattice relaxation phenomena. The observation of spin–lattice interaction suggests the presence of the Rashba–Dresselhaus spin–orbit interaction which is associated with inversion and time-reversal symmetry breaking. Additionally, the presence of negative and asymmetric longitudinal magnetoresistance indicates anomalous velocity contribution to the magnetoresistance due to the Rashba–Dresselhaus spin–orbit interaction which is further studied by heat capacity.     

A fully automated algorithm under modified FCM framework for improved brain MR image segmentation

Automated brain magnetic resonance image (MRI) segmentation is a complex problem especially if accompanied by quality depreciating factors such as intensity inhomogeneity and noise. This article presents a new algorithm for automated segmentation of both normal and diseased brain MRI. An entropy driven homomorphic filtering technique has been employed in this work to remove the bias field. The initial cluster centers are estimated using a proposed algorithm called histogram-based local peak merger using adaptive window. Subsequently, a modified fuzzy c-mean (MFCM) technique using the neighborhood pixel considerations is applied. Finally, a new technique called neighborhood-based membership ambiguity correction (NMAC) has been used for smoothing the boundaries between different tissue classes as well as to remove small pixel level noise, which appear as misclassified pixels even after the MFCM approach. NMAC leads to much sharper boundaries between tissues and, hence, has been found to be highly effective in prominently estimating the tissue and tumor areas in a brain MR scan. The algorithm has been validated against MFCM and FMRIB software library using MRI scans from BrainWeb. Superior results to those achieved with MFCM technique have been observed along with the collateral advantages of fully automatic segmentation, faster computation and faster convergence of the objective function.