Microwave Synthesis of 5-Substituted 1H-Tetrazoles Catalyzed by Bismuth Chloride in Water

Bismuth chloride was used to catalyze the [2 + 3] cycloaddition between sodium azide with aryl nitriles, aliphatic nitriles, and vinyl nitriles. A number of 5-substituted 1H-tetrazoles were synthesized in water or isopropanol/water mixtures using microwave heating. Good yields were obtained for these reactions when heated for 1 h at 120–160 °C in a 3:1 isopropanol/water mixture. A few of the less reactive nitriles required longer reaction times for good yields.     

Data and device protection: A ToF‐SIMS,wetting, and XPS study of an Apple iPod nano

An important aspect of the robustness of an electronic device is its ability to resist water, fingerprints, dirt, and smudges that may compromise its ability to function and/or the information within it. Here, we report a chemical analysis by ToF‐SIMS, wetting, and XPS of the surfaces in a commercially available Apple iPod nano (8GB, MC525LL/A), which showed good resistance to its environment. This analysis reveals that the front panel (touchscreen) of the device is coated with a low free energy fluorinated polymer that may consist of short segments of a fluorinated hydrocarbon connected through ether linkages. No other part of the device appears to have this hydrophobic coating. A plasma treatment of the device leads to a deterioration of its performance. This work demonstrates how different analytical techniques can complement each other and contribute to a better understanding of a surface or a material. Copyright © 2013 John Wiley & Sons, Ltd.     

Facile,efficient and eco-friendly synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles

A concise, two-step eco-friendly approach towards the synthesis of 5-sulfenyl tetrazole derivatives of indoles and pyrroles, is reported. The synthesis comprises the oxone-mediated thiocyanation of the starting heterocycles towards intermediate 3-thiocyanato indoles and 2-thiocyanato pyrroles, and their subsequent treatment with sodium azide in 2-propanol/water under zinc bromide promotion.     

Characterization and optimization of heroin hapten-BSA conjugates: method development for the synthesis of reproducible hapten-based vaccines

A potential new treatment for drug addiction is immunization with vaccines that induce antibodies that can abrogate the addictive effects of the drug of abuse. One of the challenges in the development of a vaccine against drugs of abuse is the availability of an optimum procedure that gives reproducible and high yielding hapten-protein conjugates. In this study, a heroin/morphine surrogate hapten (MorHap) was coupled to bovine serum albumin (BSA) using maleimide-thiol chemistry. MorHap-BSA conjugates with 3, 5, 10, 15, 22, 28, and 34 haptens were obtained using different linker and hapten ratios. Using this optimized procedure, MorHap-BSA conjugates were synthesized with highly reproducible results and in high yields. The number of haptens attached to BSA was compared by 2,4,6-trinitrobenzenesulfonic acid (TNBS) assay, modified Ellman’s test and matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Among the three methods, MALDI-TOF MS discriminated subtle differences in hapten density. The effect of hapten density on enzyme-linked immunosorbent assay (ELISA) performance was evaluated with seven MorHap-BSA conjugates of varying hapten densities, which were used as coating antigens. The highest antibody binding was obtained with MorHap-BSA conjugates containing 3–5 haptens. This is the first report that rigorously analyzes, optimizes and characterizes the conjugation of haptens to proteins that can be used for vaccines against drugs of abuse. The effect of hapten density on the ELISA detection of antibodies against haptens demonstrates the importance of careful characterization of the hapten density by the analytical techniques described.     

Synthesis,crystal structure,and electronic structure of Li2PbSiS4: a quaternary thiosilicate with a compressed chalcopyrite‐like structure

The new quaternary thiosilicate, Li₂PbSiS₄ (dilithium lead silicon tetrasulfide), was prepared in an evacuated fused‐silica tube via high‐temperature, solid‐state synthesis at 800 °C, followed by slow cooling. The crystal structure was solved and refined using single‐crystal X‐ray diffraction data. By strict definition, the title compound crystallizes in the stannite structure type; however, this type of structure can also be described as a compressed chalcopyrite‐like structure. The Li⁺ cation lies on a crystallographic fourfold rotoinversion axis, while the Pb²⁺ and Si⁴⁺ cations reside at the intersection of the fourfold rotoinversion axis with a twofold axis and a mirror plane. The Li⁺ and Si⁴⁺ cations in this structure are tetrahedrally coordinated, while the larger Pb²⁺ cation adopts a distorted eight‐coordinate dodecahedral coordination. These units join together via corner‐ and edge‐sharing to create a dense, three‐dimensional structure. Powder X‐ray diffraction indicates that the title compound is the major phase of the reaction product. Electronic structure calculations, performed using the full potential linearized augmented plane wave method within density functional theory (DFT), indicate that Li₂PbSiS₄ is a semiconductor with an indirect bandgap of 2.22 eV, which compares well with the measured optical bandgap of 2.51 eV. The noncentrosymmetric crystal structure and relatively wide bandgap designate this compound to be of interest for IR nonlinear optics.     

A Novel Dual Drug Approach That Combines Ivermectin and Dihydromyricetin (DHM) to Reduce Alcohol Drinking and Preference in Mice

Alcohol use disorder (AUD) affects over 18 million people in the US. Unfortunately, pharmacotherapies available for AUD have limited clinical success and are under prescribed. Previously, we established that avermectin compounds (ivermectin [IVM] and moxidectin) reduce alcohol (ethanol/EtOH) consumption in mice, but these effects are limited by P-glycoprotein (Pgp/ABCB1) efflux. The current study tested the hypothesis that dihydromyricetin (DHM), a natural product suggested to inhibit Pgp, will enhance IVM potency as measured by changes in EtOH consumption. Using a within-subjects study design and two-bottle choice study, we tested the combination of DHM (10 mg/kg; i.p.) and IVM (0.5–2.5 mg/kg; i.p.) on EtOH intake and preference in male and female C57BL/6J mice. We also conducted molecular modeling studies of DHM with the nucleotide-binding domain of human Pgp that identified key binding residues associated with Pgp inhibition. We found that DHM increased the potency of IVM in reducing EtOH consumption, resulting in significant effects at the 1.0 mg/kg dose. This combination supports our hypothesis that inhibiting Pgp improves the potency of IVM in reducing EtOH consumption. Collectively, we demonstrate the feasibility of this novel combinatorial approach in reducing EtOH consumption and illustrate the utility of DHM in a novel combinatorial approach.     

Recoil-proton polarization in high-energy deuteron photodisintegration with circularly polarized photons

We measured the angular dependence of the three recoil-proton polarization components in two-body photodisintegration of the deuteron at a photon energy of 2 GeV. These new data provide a benchmark for calculations based on quantum chromodynamics. Two of the five existing models have made predictions of polarization observables. Both explain the longitudinal polarization transfer satisfactorily. Transverse polarizations are not well described, but suggest isovector dominance.     

High resolution spectroscopy of (lambda)(12)B by electroproduction

An experiment measuring electroproduction of hypernuclei has been performed in hall A at Jefferson Lab on a 12C target. In order to increase counting rates and provide unambiguous kaon identification two superconducting septum magnets and a ring imaging Cherenkov detector were added to the hall A standard equipment. An unprecedented energy resolution of less than 700 keV FWHM has been achieved. Thus, the observed (Lambda)(12)B spectrum shows for the first time identifiable strength in the core-excited region between the ground-state s-wave Lambda peak and the 11 MeV p-wave Lambda peak.     

Adult neurogenesis and specific replacement of interneuron subtypes in the mouse main olfactory bulb

Background  

New neurons are generated in the adult brain from stem cells found in the subventricular zone (SVZ). These cells proliferate in the SVZ, generating neuroblasts which then migrate to the main olfactory bulb (MOB), ending their migration in the glomerular layer (GLL) and the granule cell layer (GCL) of the MOB. Neuronal populations in these layers undergo turnover throughout life, but whether all neuronal subtypes found in these areas are replaced and when neurons begin to express subtype-specific markers is not known.