Synthesis of WS2 and MoS2 fullerene-like nanoparticles from solid precursors

Inorganic fullerene-like WS₂ and MoS₂ nanoparticles have been synthesized using exclusively solid precursors, by reaction of the corresponding metal oxide nanopowder, sulfur and a hydrogen-releasing agent (NaBH₄ or LiAlH₄), achieved either by conventional furnace heating up to ∼900 °C or by photothermal ablation at far higher temperatures driven by highly concentrated white light. In contrast to the established syntheses that require toxic and hazardous gases, working solely with solid precursors permits relatively safer reactor conditions conducive to industrial scale-up.      

Preface

Ethik in der Medizin -     

Presence of multiple "Helicobacter heilmannii" strains in an individual suffering from ulcers and in his two cats

Circumstantial evidence suggests that "Helicobacter heilmannii" infection is an example of zoonosis. The presence of "H. heilmannii" strains in a human subject with acute gastric erosions, in his two cats, and in two unrelated cats was analyzed, and the genetic relatedness of the human and feline strains was assessed. A 580-bp, PCR-amplified sequence of "H. heilmannii" urease B gene (ureB) obtained from biopsies from the human subject and his two cats was restricted with AluI and cloned for sequencing. Analysis of the restriction fragment length polymorphism of the ureB-amplified product suggested the presence of different individual "H. heilmannii" strains in the cats and of three distinct strains in the human subject. One of the "H. heilmannii" ureB sequences amplified from the human subject's biopsies was identical to that derived from one of his cats. The degree of similarity between the other "H. heilmannii" human and feline nucleotide sequences was higher than 97%. Most of the base substitutions were conservative. We conclude that human and animal "H. heilmannii" strains are closely related and that humans can be infected by more than one "H. heilmannii" strain, as has been observed for Helicobacter pylori.     

Transneuronal retrograde viral labeling in the brain stem and hypothalamus is more intense from the left than from the right adrenal gland

Previous studies using the viral transneuronal tracing technique demonstrated central autonomic circuits involved in the innervation of the adrenal gland. Since increasing number of data indicate laterality in the neuroendocrine system, we aimed to investigate whether the supraspinal innervation of the adrenal gland exhibits asymmetry or not. The central circuitry involved in the innervation of the left and the right adrenal gland was studied in individual rats by dual transneuronal tracing using isogenic recombinant strains (Ba-DupGreen and Ba-Duplac expressing lacZ) of Bartha strain of pseudorabies virus. Viral infection of brain nuclei (dorsal vagal nucleus, nucleus of the solitary tract, caudal raphe nuclei, A5 cell group, hypothalamic paraventricular nucleus) from the left adrenal was more severe than that from the right organ. Dual-infected neurons were present both in the brain stem and in the hypothalamus. The results indicate a predominance in the supraspinal innervation of the left adrenal gland, and that each adrenal gland is innervated both by side-specific neurons and by neurons that project to both organs.     

Determination of conjugated monoamine metabolites in brain tissue

Levels of free and conjugated monoamine metabolites were analysed in brain tissue of rat and man. In the rat the conjugates were mainly of the sulfate ester type. The levels of conjugated dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) constituted 40--50% of the total amount of the metabolites. 4-Hydroxy-3-methoxy-phenylglycol (HMPG) and 5-hydroxy-3-indoleacetic acid (5-HIAA) were present as conjugates in 90 and 10% of the total levels. Chlorpromazine treatment resulted in an elevation of both the free and the conjugated forms of the dopamine metabolites and HMPG. In a human caudate nucleus obtained at autopsy both DOPAC and HMPG were present in the free form and as sulfate and glucuronide conjugates. The major dopamine metabolite found in this human brain was HVA. This metabolite and 5-HIAA occurred predominantly as free metabolites.     

Poly Threo-β-Hydroxy Aspartic Acid

The N-carboxy-anhydrides of β - benzyl O-t-butyl-threo-β-hydroxy-DL- and L-aspartate were polymerized. The two protecting groups, i. e., t-butyl and benzyl groups, could be removed stepwise without degradation of the DL-polymer.     

Enhanced mechanical properties of electrospun nano-fibers through NaCl mediation

Electrospun (ES) nano-scale polymer fibers are known to exhibit lower Young's modulus and strength than their bulk counterpart. We have discovered that minute additions of sodium chloride (NaCl) during the preparation stage of ES polymethyl methacrylate (PMMA) fibers raises the fiber mechanical properties in a significant way, nearly up to bulk values, over a range of diameters. NaCl-induced electrical effects leading to enhanced molecular alignment during nano-fiber formation is the most likely explanation for this synergistic effect. Moreover, beyond the now-recognized rise in Young's modulus values, we observed that the strength and tensile toughness of the ES fibers also significantly increase at progressively smaller diameters.