Smoke Composition to Disseminate Capsaicinoids in Atmosphere as Sensory Irritant

Dissemination of sensory irritants in the atmosphere with the help of an evaporating mixtureis adopted. Experiments were carried out to find an alternative sensory irritant which is moreirritating and less toxic than the existing sensory irritating agents and originating from a naturalsource. Extract of red pepper, the oleoresin, is less toxic than the existing sensory irritants andis analysed for its constituents. Thermal studies of capsaicin and the composition indicate thatthe composition ignites at 190 °C whereas capsaicinoids boil at 214 °C. Lactose-KClO3 reactionwas found to release sufficient thermal energy to evaporate capsaicinoids into the atmospherewithout degeneration. The compositions are both friction and impact insensitive. Thedissemination of capsaicinoids into the atmosphere was confirmed using HPLC technique

Nanocrystalline Pentaerythritoltetranitrate using Sol-Gel Process

The secondary explosives developed with reduced particle size tend to be more insensitive for mechanical stimuli and may release energy with faster rate and gaining more importance nowadays. Therefore, aiming to reduce the particle size of one of the popular explosives, viz., pentaerythritoltetranitrate (PETN) to the nanometer range, a method for preparation of nanocrystalline PETN in the silica (SiO2) gel matrix using sol-gel process has been demonstrated. The PETN-SiO2 xerogels were prepared containing PETN content ranging from 50 per cent to 90 per cent (w/w) and the xerogels were characterised using different techniques. An exothermic peak at around 185 oC preceded by an endotherm in thermal analysis accompanied with weight loss in the temperature range from 150 oC to 200 oC   for the xerogel confirmed the presence of PETN in xerogel. Infrared spectra of xerogels showed peaks at around 1285 cm-1 and 1700 cm-1 assigned to O-NO2 and C-O bond representing PETN. Small angle x-ray scattering measurements on xerogels indicated that PETN entered in the pores of silica matrix. Transmission electron microscopy revealed that cystalline PETN    with particle size of around 15 nm dispersed in silica xerogel. The specific surface area for the PETN-SiO2 (90:10) xerogels was found to be 75 m2/g.Defence Science Journal, 2011, 61(6), pp.534-539, DOI:http://dx.doi.org/10.14429/dsj.61.59

Coupling proteomics and metabolomics for the unsupervised identification of protein-metabolite interactions in Chaetomium thermophilum

Protein-metabolite interactions play an important role in the cell's metabolism and many methods have been developed to screen them in vitro. However, few methods can be applied at a large scale and not alter biological state. Here we describe a proteometabolomic approach, using chromatography to generate cell fractions which are then analyzed with mass spectrometry for both protein and metabolite identification. Integrating the proteomic and metabolomic analyses makes it possible to identify protein-bound metabolites. Applying the concept to the thermophilic fungus Chaetomium thermophilum, we predict 461 likely protein-metabolite interactions, most of them novel. As a proof of principle, we experimentally validate a predicted interaction between the ribosome and isopentenyl adenine

FDR-controlled metabolite annotation for high-resolution imaging mass spectrometry

© 2017 Nature America, Inc., part of Springer Nature. All rights reserved.High-mass-resolution imaging mass spectrometry promises to localize hundreds of metabolites in tissues, cell cultures, and agar plates with cellular resolution, but it is hampered by the lack of bioinformatics tools for automated metabolite identification. We report pySM, a framework for false discovery rate (FDR)-controlled metabolite annotation at the level of the molecular sum formula, for high-mass-resolution imaging mass spectrometry (https://github.com/alexandrovteam/pySM). We introduce a metabolite-signal match score and a target-decoy FDR estimate for spatial metabolomics

Catalytic Enantioselective Cross-Couplings of Secondary Alkyl Electrophiles with Secondary Alkylmetal Nucleophiles: Negishi Reactions of Racemic Benzylic Bromides with Achiral Alkylzinc Reagents

We have developed a nickel-catalyzed method for the asymmetric cross-coupling of secondary electrophiles with secondary nucleophiles, specifically, stereoconvergent Negishi reactions of racemic benzylic bromides with achiral cycloalkylzinc reagents. In contrast to most previous studies of enantioselective Negishi cross-couplings, tridentate pybox ligands are ineffective in this process; however, a new, readily available bidentate isoquinoline–oxazoline ligand furnishes excellent ee’s and good yields. The use of acyclic alkylzinc reagents as coupling partners led to the discovery of a highly unusual isomerization that generates a significant quantity of a branched cross-coupling product from an unbranched nucleophile

Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking

The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry techniques are well-suited to high-throughput characterization of natural products, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social molecular networking (GNPS, http://gnps.ucsd.edu), an open-access knowledge base for community wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of ‘living data’ through continuous reanalysis of deposited data

Preparation and Structure of Uranium-Incorporated Gd₂Zr₂O₇ Compounds and Their Thermodynamic Stabilities under Oxidizing and Reducing Conditions

Gd₂Zr₂O₇ is being contemplated as a futuristic matrix for the incorporation of high-level radioactive nuclear waste. This compound has the unique ability to incorporate several fission products and heavy metal ions like uranium and thorium into its lattice sites without undergoing structural changes. X-ray diffraction analyses of Gd_2–<i>x</i>U_<i>x</i>Zr₂O_7+δ samples indicate that the parent compound can incorporate a substantial amount of uranium, both under oxidizing and reducing conditions. The oxidation state of these samples was investigated by X-ray photoelectron spectroscopy. The thermodynamic stability of uranium-substituted Gd₂Zr₂O₇ is an important parameter that will govern the long-term storage of uranium and minor actinides in this matrix. High-temperature calorimetry has been used to investigate the stability of the Gd_2–<i>x</i>U_<i>x</i>Zr₂O_7+δ (0.00 ≤ <i>x</i> ≤ 0.15) compositions. The standard molar free energy of the formation of Gd_2–<i>x</i>U_<i>x</i>Zr₂O_7+δ (0.00 ≤ <i>x</i> ≤ 0.15) compositions has been estimated. From the free energy of formation data, the sample corresponding to <i>x</i> = 0.15 was found to be most stable in the Gd_2–<i>x</i>U_<i>x</i>Zr₂O_7+δ (0.00 ≤ <i>x</i> ≤ 0.15) series. The relative stabilities of U⁴⁺ and U⁶⁺ substituted gadolinium zirconate have been discussed on the basis of the charge on the uranium ion and the incorporation of corresponding extra oxygen atoms into the lattice for charge compensation

FDR-controlled metabolite annotation for high-resolution imaging mass spectrometry

© 2017 Nature America, Inc., part of Springer Nature. All rights reserved.High-mass-resolution imaging mass spectrometry promises to localize hundreds of metabolites in tissues, cell cultures, and agar plates with cellular resolution, but it is hampered by the lack of bioinformatics tools for automated metabolite identification. We report pySM, a framework for false discovery rate (FDR)-controlled metabolite annotation at the level of the molecular sum formula, for high-mass-resolution imaging mass spectrometry (https://github.com/alexandrovteam/pySM). We introduce a metabolite-signal match score and a target-decoy FDR estimate for spatial metabolomics

FDR-controlled metabolite annotation for high-resolution imaging mass spectrometry

© 2017 Nature America, Inc., part of Springer Nature. All rights reserved.High-mass-resolution imaging mass spectrometry promises to localize hundreds of metabolites in tissues, cell cultures, and agar plates with cellular resolution, but it is hampered by the lack of bioinformatics tools for automated metabolite identification. We report pySM, a framework for false discovery rate (FDR)-controlled metabolite annotation at the level of the molecular sum formula, for high-mass-resolution imaging mass spectrometry (https://github.com/alexandrovteam/pySM). We introduce a metabolite-signal match score and a target-decoy FDR estimate for spatial metabolomics