First report of isolation of maleamic acid from natural source Polygonatum cirrhifolium—A potential chemical marker for identification

Polygonatum cirrhifolium (Meda) plant is being used in number of rejuvenating Ayurvedic formulations. Ever rising demands, lack of natural sources, and insufficient quantity, to meet the requirements of market, the raw material has led toward the use of official substitutes recommended by the Department of AYUSH that has further encouraged manufacturers for adulteration of formulations by other substandard/spurious raw drugs. Literature reveals that more than 60% Ayurvedic parameters as well as pharmacological actions of Ashtawarga plants do not match with their substitutes leading to reduced efficacy of the drugs along with loss of faith for use of herbal drugs. Consumers are forced to pay for the material which has never been used for high-cost claimed formulation. The situation is being exploited by manufacturers because regulatory authorities lack the tools (marker compound) needed for identification of authentic plant. Methanolic extract of rhizomes of plant was subjected to column chromatography. Isolated compound has been characterized as (Z)-4-amino-4-oxobut-2-enoic acid (maleamic acid/maleamate/maleic monoamide/maleic acid monoamide) by chemical test, melting point, IR/NMR/mass/UV spectral analysis. It is the first report in Polygonatum genus and can be used as a marker for identification of the plant in market formulations.     

Electrothermal analysis in two-layered couple stress fluid flow in an asymmetric microchannel via peristaltic pumping

Journal of Thermal Analysis and Calorimetry - Being motivated from the recent developments in biomicrofluidics, a mathematical model is presented to analyze the two-layered electrothermal flow via...     

Effects due to body-forces and body-couples in the interior of a micropolar elastic half-space—I

A general solution of the equilibrium equations is obtained for a half-space with a fixed boundary and arbitrary but axisymmetric distribution of body forces and body couples in the interior of the half-space. Few particular cases have been investigated in detail. The stresses have been obtained at the boundary and the displacements have been obtained in the interior of the half-space. Numerical results have been displayed graphically.

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Zusammenfassung Eine allgemeine lösung für Gleichgewicht eines Halbraums mit festem Rand und einer beliebigen, aber antisymmetrischen Verteilung von Körperkräften und Körpermomenten im Inneren wird gefunden. Einige Spezialfälle wurden ansführlich erforscht. Die Spannungen am Rand und die Verschiebungen im Inneren des Halbraums wurden erhalten. Numerische Resultate wurden graphisch dargestellt.

     

Surface Modification of Ultra-high Molecular Weight Polyethylene Membranes Using Underwater Plasma Polymerization

Ultra-high molecular weight polyethylene membranes were modified and subsequently polymer coated using the underwater plasma produced by glow discharge electrolysis. This plasma pretreatment generated various O-functional groups among them OH groups have dominated. This modified inner (pore) surface of membranes showed complete wetting and strong adhesion to a hydrogel copolymerized by glow discharge electrolysis also. The deposited hydrogel consists of plasma polymerized acrylic acid crosslinked by copolymerization with the bifunctional N,N′-methylenebis(acrylamide). Tuning the hydrogel hydrophilicity and bio-compatibility poly(ethylene glycol) was chemically inserted into the copolymer. Such saturated polymer could only be inserted on a non-classic way by (partial) fragmentation and recombination thus demonstrating the exotic properties of the underwater plasma. The modification of membrane was achieved by squeezing the reactive plasma solution into the pores by plasma-induced shock waves and supported by intense stirring. The deposited copolymer hydrogel has filled all pores also in the inner of membrane as shown by scanning electron microscopy of cross-sections. The copolymer shows the characteristic units of acrylic acid and ethylene glycol as demonstrated by infrared spectroscopy. A minimum loss in carboxylic groups of acrylic acid during the plasma polymerization process was confirmed by X-ray photoelectron spectroscopy. Additional cell adhesion tests on copolymer coated polyethylene using IEC-6 cells demonstrated the bio-compatibility of the plasma-deposited hydrogel.     

Spectroscopic techniques in medicine: The future of diagnostics

Spectroscopic techniques have been finding increasing applications in the field of biomedicine especially in the field of disease diagnosis and monitoring in spite of the rapid emergence of several molecular biology based techniques. The significance of spectroscopy techniques and the possibility of using some of the underutilized regions of the electromagnetic radiations are discussed in this review. While previous reviews have already dealt with the potential of Fourier transform infrared spectroscopy-based (FTIR) techniques for clinical applications, the present review addresses the lacunae of the techniques along with its future trends that may make it a technique routinely applied in clinical settings.     

Synthesis of substituted acetylenes, aryl-alkyl ethers, 2-alkene-4-ynoates and nitriles using heterogeneous mesoporous Pd-MCM-48 as reusable catalyst

Pd-MCM-48 has been employed as a heterogeneous catalyst for the synthesis of substituted acetylenes via Sonogashira reactions under copper and amine-free reaction conditions. In addition, the catalyst exhibited excellent regioselectivity for primary alcohols towards C-O coupling leading to formation of alkyl-aryl ethers in high yields. A green procedure for the stereoselective synthesis of 2-alkene-4-ynoates and nitriles from the reactions of vic-(E)-diiodoalkenes with activated alkenes has also been demonstrated using Pd-MCM-48 catalyst. The catalyst was easily recovered from the reaction mixture by filtration and reused for at least six times with minimal loss of activity.     

Rules of Boron–Nitrogen Doping in Defect Graphene Sheets: A First‐Principles Investigation of Band‐Gap Tuning and Oxygen Reduction Reaction Catalysis Capabilities

Introduction of defects and nitrogen doping are two of the most pursued methods to tailor the properties of graphene for better suitability to applications such as catalysis and energy conversion. Doping nitrogen atoms at defect sites of graphene and codoping them along with boron atoms can further increase the efficiency of such systems due to better stability of nitrogen at defect sites and stabilization provided by B?N bonding. Systematic exploration of the possible doping/codoping configurations reflecting defect regions of graphene presents a prevalent doping site for nitrogen‐rich BN clusters and they are also highly suitable for modulating (0.2–0.9 eV) the band gap of defect graphene. Such codoped systems perform significantly better than the platinum surface, undoped defect graphene, and the single nitrogen or boron atom doped defect graphene system for dioxygen adsorption. Significant stretching of the O?O bond indicates a lowering of the bond breakage barrier, which is advantageous for applications in the oxygen reduction reaction.     

Heterometallic Triply‐Bridging Bis‐Borylene Complexes

Triply‐bridging bis‐{hydrido(borylene)} and bis‐borylene species of groups 6, 8 and 9 transition metals are reported. Mild thermolysis of [Fe₂(CO)₉] with an in situ produced intermediate, generated from the low‐temperature reaction of [Cp*WCl₄] (Cp*=η⁵‐C₅Me₅) and [LiBH₄?THF] afforded triply‐bridging bis‐{hydrido(borylene)}, [(μ₃‐BH)₂H₂{Cp*W(CO)₂}₂{Fe(CO)₂}] ( 1 ) and bis‐borylene, [(μ₃‐BH)₂{Cp*W(CO)₂}₂{Fe(CO)₃}] ( 2 ). The chemical bonding analyses of 1 show that the B?H interactions in bis‐{hydrido (borylene)} species is stronger as compared to the M?H ones. Frontier molecular orbital analysis shows a significantly larger energy gap between the HOMO‐LUMO for 2 as compared to 1 . In an attempt to synthesize the ruthenium analogue of 1 , a similar reaction has been performed with [Ru₃(CO)₁₂]. Although we failed to get the bis‐{hydrido(borylene)} species, the reaction afforded triply‐bridging bis‐borylene species [(μ₃‐BH)₂{WCp*(CO)₂}₂{Ru(CO)₃}] ( 2′ ), an analogue of 2 . In search for the isolation of bridging bis‐borylene species of Rh, we have treated [Co₂(CO)₈] with nido‐[(RhCp*)₂(B₃H₇)], which afforded triply‐bridging bis‐borylene species [(μ₃‐BH)₂(RhCp*)₂Co₂(CO)₄(μ‐CO)] ( 3 ). All the compounds have been characterized by means of single‐crystal X‐ray diffraction study; ¹H, ¹¹B, ¹³C NMR spectroscopy; IR spectroscopy and mass spectrometry.     

Nuclear Quadrupole Interactions in Nuclear Quadrupole Resonance Detection of Energetic and Controlled Materials: Theoretical Study

There has been a growing interest in nuclear quadrupole resonance (NQR) techniques useful for the detection of explosives and drugs in solid state systems. This paper uses the first-principles one-electron Hartree?CFock theoretical method to study the nuclear quadrupole interaction parameters e ² qQ and ?? for the ¹⁴N nuclei in the explosives RDX and ??-HMX as well as the drugs cocaine and heroin. It has been found in our earlier published investigations reviewed here that there is very good agreement for our calculated e ² qQ and ?? for ¹⁴N, for all these four systems, and experiment. We also present our unpublished theoretical results for cocaine with an HCl molecule attached. We successfully explain quantitatively the drastic decrease in e ² qQ in going to cocaine-HCl from cocaine-free base as well as the observed substantial increase in ?? and discuss the implications of these dramatic changes for NQR detection in general.