110 research outputs found

    Differential cross sections for muonic atom scattering in solid hydrogenic targets

    Full text link
    The differential cross sections for low-energy muonic hydrogen atom scattering in solid molecular H2_2, D2_2 and T2_2 targets under low pressure have been calculated for various temperatures. The polycrystalline fcc and hcp structure of the solid hydrogenic targets are considered. The Bragg and phonon scattering processes are described using the Debye model of a solid. The calculated cross sections are used for Monte Carlo simulations of the muonic atom slowing down in these targets. They have been successfully applied for a description of the production of the muonic atom beams in the multilayer hydrogenic crystals.Comment: 23 pages, 19 figures, 2 table

    Enantiospecific sp(2)-sp(3) coupling of secondary and tertiary boronic esters

    Get PDF
    The cross-coupling of boronic acids and related derivatives with sp² electrophiles (the Suzuki–Miyaura reaction) is one of the most powerful C–C bond formation reactions in synthesis, with applications that span pharmaceuticals, agrochemicals and high-tech materials. Despite the breadth of its utility, the scope of this Nobel prize-winning reaction is rather limited when applied to aliphatic boronic esters. Primary organoboron reagents work well, but secondary and tertiary boronic esters do not (apart from a few specific and isolated examples). Through an alternative strategy, which does not involve using transition metals, we have discovered that enantioenriched secondary and tertiary boronic esters can be coupled to electron-rich aromatics with essentially complete enantiospecificity. As the enantioenriched boronic esters are easily accessible, this reaction should find considerable application, particularly in the pharmaceutical industry where there is growing awareness of the importance of, and greater clinical success in, creating biomolecules with three-dimensional architectures

    Модернизация технологического процесса механической обработки детали ступица КЗК 12-0602605 с разработкой проекта участка цеха, средств технологического оснащения и исследованием электрохимического шлифования

    Get PDF
    Bimetallic Pd/Cu and Pd/Ag catalytic systems were used for borylation of propargylic alcohol derivatives. The substrate scope includes even terminal alkynes. The reactions proceed stererospecifically with formal S(N)2' pathways to give allenyl boronates. Opening of propargyl epoxides leads to 1,2-diborylated butadienes probably via en allenylboronate intermediate.AuthorCount:4;</p

    Apaf-1- and Caspase-8-independent apoptosis.

    Get PDF
    Two major apoptosis pathways, the mitochondrial and death receptor pathways, are well recognized. Here we established cell lines from the fetal thymus of Apaf-1-, Caspase-9-, or Bax/Bak-deficient mice. These cell lines were resistant to apoptosis induced by DNA-damaging agents, RNA or protein synthesis inhibitors, or stress in the endoplasmic reticulum. However, they underwent efficient apoptosis when treated with kinase inhibitors such as staurosporine and H-89, indicating that these inhibitors induce a caspase-dependent apoptosis that is different from the mitochondrial pathway. CrmA, a Caspase-8 inhibitor, did not prevent staurosporine-induced apoptosis of fetal thymic cell lines, suggesting that the death receptor pathway was also not involved in this process. The staurosporine-induced cell death was inhibited by okadaic acid, a serine/threonine phosphatase inhibitor, suggesting that dephosphorylation of a proapoptotic molecule triggered the death process, or that phosphorylation of an antiapoptotic molecule could block the process. Cells of various types (fetal thymocytes, bone marrows, thymocytes, and splenocytes), but not embryonic fibroblasts, were sensitive to the noncanonical staurosporine-induced apoptosis, suggesting that the noncanonical apoptosis pathway is tissue specific
    corecore