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Synthesis Mechanism (synthesis + mechanism)
Selected AbstractsSynthesis Mechanism of an Iron,Chromium Ceramic PigmentJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2000Agustín Escardino The synthesis of a black Fe2O3,Cr2O3 pigment has been studied to better understand the synthesis mechanism. A mechanism is proposed according to which, under the tested operating conditions, one of the starting constituents (Cr2O3) is transferred, largely in a gas phase (after subliming), to the particle surface of the other constituent (Fe2O3), at which it is deposited or chemisorbed, forming a layer from which it diffuses inward into the Fe2O3 particles. The process stops when the composition of the resulting solid solution has become uniform. [source] In Situ UV Raman Spectroscopic Study on the Synthesis Mechanism of AlPO-5,ANGEWANDTE CHEMIE, Issue 46 2009Fengtao Fan Ein weiteres Puzzleteil: Der Mechanismus der AlPO-5-Synthese wurde durch In-situ-UV-Raman-Spektroskopie in Verbindung mit der Fenton-Reaktion auf molekularer Ebene untersucht. Die Ergebnisse geben Einblick in die Rolle des Templats bei der Kanalbildung und ermöglichen die Identifizierung der am Gerüstaufbau beteiligten Bausteine. [source] In Situ UV Raman Spectroscopic Studies on the Synthesis Mechanism of Zeolite XCHEMISTRY - A EUROPEAN JOURNAL, Issue 17 2008Fengtao Fan A specially fabricated in situ Raman cell was coupled to a UV Raman spectrometer to investigate both the solid and liquid phases during the formation of zeolite X under high temperatures and pressures (see picture). It is proposed that 4-rings formed at initial nucleation interconnect with each other via 6-rings to form the zeolite X framework. [source] Microstructural analysis of iron aluminide formed by self-propagating high-temperature synthesis mechanism in aluminium matrix compositeJOURNAL OF MICROSCOPY, Issue 1 2006ANITA OLSZÓWKA-MYALSKA Summary An aluminium matrix composite with iron aluminide formed in situ as a result of self-propagated high-temperature synthesis was examined. The structural characteristics of the reinforcement investigated by scanning electron microscopy and transmission electron microscopy methods are presented. Iron aluminide particles with a very fine grain size and of two shapes, cubic and needle-like, were observed. No differences in their phase composition were found by the selective electron diffraction pattern method. The composite reinforcement formed in the early stage of self-propagating high-temperature synthesis consisted only of the Al3Fe phase. [source] GABA synthesis in Schwann cells is induced by the neuroactive steroid allopregnanoloneJOURNAL OF NEUROCHEMISTRY, Issue 4 2010Valerio Magnaghi J. Neurochem. (2009) 112, 980,990. Abstract Recent evidence showed that neurotransmitters are synthesised in glial cells, such as the Schwann cells, which form myelin sheaths in the PNS. While the presence of GABA type A (GABA-A) receptors has been previously demonstrated in these cells, the evidence of GABA synthesis remained still elusive. In an attempt to demonstrate the presence of GABA in rat Schwann cells, we adopted a strategy, using several integrated neurochemical, molecular as well as immunocytochemical approaches. We first demonstrated the presence of glutamic acid decarboxylase of 67 kDa (GAD67) in Schwann cells, a crucial enzyme of the GABA synthesis mechanism. Second, we demonstrated that GABA is synthesized and localized in Schwann cells. As the third step we showed that allopregnanolone (10 nM), a potent allosteric modulator of GABA-A receptors, stimulates GABA synthesis through increased levels of GAD67 in Schwann cells. Analysis of intracellular signalling mechanisms revealed that the protein kinase A pathway, through enhanced cAMP levels and cAMP response element binding protein phosphorylation, modulates the allosteric action of allopregnanolone at the GABA-A receptor in Schwann cells. Our findings are the first to demonstrate that this GABA mechanism is active in Schwann cells thus establishing new potential therapeutic targets to control Schwann cell biology, which may prove useful in the treatment of several neurodegenerative disorders. [source] Synthesis Mechanism of an Iron,Chromium Ceramic PigmentJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2000Agustín Escardino The synthesis of a black Fe2O3,Cr2O3 pigment has been studied to better understand the synthesis mechanism. A mechanism is proposed according to which, under the tested operating conditions, one of the starting constituents (Cr2O3) is transferred, largely in a gas phase (after subliming), to the particle surface of the other constituent (Fe2O3), at which it is deposited or chemisorbed, forming a layer from which it diffuses inward into the Fe2O3 particles. The process stops when the composition of the resulting solid solution has become uniform. [source] Identification of an arsenic tolerant double mutant with a thiol-mediated component and increased arsenic tolerance in phyA mutantsTHE PLANT JOURNAL, Issue 6 2007Dong-Yul Sung Summary A genetic screen was performed to isolate mutants showing increased arsenic tolerance using an Arabidopsis thaliana population of activation tagged lines. The most arsenic-resistant mutant shows increased arsenate and arsenite tolerance. Genetic analyses of the mutant indicate that the mutant contains two loci that contribute to arsenic tolerance, designated ars4 and ars5. The ars4ars5 double mutant contains a single T-DNA insertion, ars4, which co-segregates with arsenic tolerance and is inserted in the Phytochrome A (PHYA) gene, strongly reducing the expression of PHYA. When grown under far-red light conditions ars4ars5 shows the same elongated hypocotyl phenotype as the previously described strong phyA-211 allele. Three independent phyA alleles, ars4, phyA-211 and a new T-DNA insertion allele (phyA-t) show increased tolerance to arsenate, although to a lesser degree than the ars4ars5 double mutant. Analyses of the ars5 single mutant show that ars5 exhibits stronger arsenic tolerance than ars4, and that ars5 is not linked to ars4. Arsenic tolerance assays with phyB-9 and phot1/phot2 mutants show that these photoreceptor mutants do not exhibit phyA -like arsenic tolerance. Fluorescence HPLC analyses show that elevated levels of phytochelatins were not detected in ars4, ars5 or ars4ars5, however increases in the thiols cysteine, , -glutamylcysteine and glutathione were observed. Compared with wild type, the total thiol levels in ars4, ars5 and ars4ars5 mutants were increased up to 80% with combined buthionine sulfoximine and arsenic treatments, suggesting the enhancement of mechanisms that mediate thiol synthesis in the mutants. The presented findings show that PHYA negatively regulates a pathway conferring arsenic tolerance, and that an enhanced thiol synthesis mechanism contributes to the arsenic tolerance of ars4ars5. [source] | |||||||||||||