Autocatalysis
Mostrando 1-12 de 23 artigos, teses e dissertações.
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1. Martensite Transformation Intergrain and Intragrain Autocatalysis in Fe-Ni alloys
This work presents a consolidated view of the autocatalysis, thermal and entropic effects in martensitic transformation of polycrystalline Fe-31wt%Ni-0.02wt%C, which has been a standard material for the investigation of fundamental aspects of the martensite transformation. The present work is based on the description of classical microstructure descriptors o
Mat. Res.. Publicado em: 24/08/2017
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2. Autocatalysis, Entropic Aspects and the Martensite Transformation Curve in Iron-Base Alloys
This study advances a methodology that consolidates the description of time-dependent (isothermal) as well as time-independent (athermal) martensitic transformation curves. Our model is applied in an extended 3-space, thus permitting inclusion of the effects of autocatalysis on nucleation to be distinguished from the initiation of the transformation, as infl
Mat. Res.. Publicado em: 09/01/2017
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3. Evolução biomolecular homoquiral: a origem e a amplificação da quiralidade nas moléculas da vida
The fact that biologically relevant molecules exist only as one of the two enantiomers is a fascinating example of complete symmetry breaking of chirality and has long intrigued our curiosity. The origin of this selective chirality has remained a fundamental enigma with regard to the origin of life since the time of Pasteur, 160 years ago. The symmetry break
Química Nova. Publicado em: 2010
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4. Replicadores computacionais: propriedades básicas e modelagens preliminares
A replicação molecular foi introduzida como uma possível teoria para explicar a origem da vida. Desde sua proposição, ela vem sendo estudada extensivamente a partir de uma perspectiva bioquímica. Baseado na literatura de replicadores moleculares, esta dissertação organiza e propõe uma taxonomia para as principais propriedades dos replicadores que se
Publicado em: 2010
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5. Theoretical studies of models with chiral amplification in asymmetrical catalysis and autocatalysis reactions in organozinc additions to aldehydes / Estudos teÃricos de modelos de catÃlise assimÃtrica e autocatÃlise em reaÃÃo de adiÃÃo de organozinco a aldeÃdos
Foram realizados cÃlculos de quÃmica quÃntica de otimizaÃÃo de geometria, incluindo estados de transiÃÃo, de molÃculas e de complexos contendo Ãtomos de zinco envolvidos em reaÃÃes de adiÃÃo de organozinco a aldeÃdos por meio de catÃlise e autocatÃlise assimÃtrica que apresentam elevados excessos enantiomÃricos. Os resultados obtidos demons
Publicado em: 2004
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6. Asymmetric autocatalysis: Novel structures, novel mechanism?
The amplifying asymmetric autocatalysis discovered by Soai and coworkers in 1995 does not fit easily into the extensively investigated framework of organozinc alkylation of aldehydes. In that case the catalyst is a monomeric Zn chelate that functions as both Lewis acid and Lewis base, permitting the simultaneous coordination of both dialkylzinc reagent and a
National Academy of Sciences.
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7. Autocatalysis in a Reconstituted Chloroplast System 1
In whole plants and intact chloroplasts, photosynthesis does not reach its full rate immediately upon illumination but only after a lag which is believed to reflect an autocatalytic increase in the concentration of carbon cycle intermediates. Autocatalysis has now been observed in a reconstituted system containing envelope-free chloroplasts augmented with fe
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8. Adenovirus type 2 endopeptidase: an unusual phosphoprotein enzyme matured by autocatalysis.
A 19-kDa protein, present in low copy number in purified adenovirus type 2, has been characterized. Several criteria were used to establish that this protein is neither a degradation product of the known structural proteins of the virion nor a minor, unusually modified, form of protein VII. This 19-kDa protein, unlike other virion proteins, possesses alkali-
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9. Mirror-symmetry breaking in the Soai reaction: A kinetic understanding
Kinetic modeling using nonlinear differential equations is proposed to analyze the spontaneous generation of enantiomeric excess in the autocatalytic addition of diisopropylzinc to prochiral pyrimidine carbaldehydes (Soai reaction). Our approach reproduces experimentally observed giant chiral amplification from an initial enantiomeric excess of <10–6% to >
National Academy of Sciences.
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10. Analysis of mammalian 20S proteasome biogenesis: the maturation of beta-subunits is an ordered two-step mechanism involving autocatalysis.
Maturation of eukaryotic 20S proteasomes involves the processing of beta-subunits by limited proteolysis. To study the processing mechanism we analysed different point mutations of the beta-subunit LMP2 in transfected human T2 cells. Here we show that the presence of the intact Gly-1Thr1 consensus motif and Lys33 are essential for correct processing. Mutatio
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11. Redox-dependent activation of CO dehydrogenase from Rhodospirillum rubrum
Studies of initial activities of carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum show that CODH is mostly inactive at redox potentials higher than −300 mV. Initial activities measured at a wide range of redox potentials (0–500 mV) fit a function corresponding to the Nernst equation with a midpoint potential of −316 mV. Previously, exten
The National Academy of Sciences.
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12. Role of substrate inhibition kinetics in enzymatic chemical oscillations.
Two chemical kinetic models are investigated using standard nonlinear dynamics techniques to determine the conditions under which substrate inhibition kinetics can lead to oscillations. The first model is a classical substrate inhibition scheme based on Michaelis-Menten kinetics and involves a single substrate. Only when this reaction takes place in a flow r