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61.
Johanna Méndez Arias Anelize de Oliveira Moraes Luiz Felipe Amarante Modesto Aline Machado de Castro Nei Pereira Jr 《Applied biochemistry and biotechnology》2017,181(2):593-603
Poly(ethylene glycol) (PEG 4000) and bovine serum albumin (BSA) were investigated with the purpose of evaluating their influence on enzymatic hydrolysis of sugarcane bagasse. Effects of these supplements were assayed for different enzymatic cocktails (Trichoderma harzianum and Penicillium funiculosum) that acted on lignocellulosic material submitted to different pretreatment methods with varying solid (25 and 100 g/L) and protein (7.5 and 20 mg/g cellulose) loadings. The highest levels of glucose release were achieved using partially delignified cellulignin as substrate, along with the T. harzianum cocktail: increases of 14 and 18 % for 25 g/L solid loadings and of 33 and 43 % for 100 g/L solid loadings were reached for BSA and PEG supplementation, respectively. Addition of these supplements could maintain hydrolysis yield even for higher solid loadings, but for higher enzymatic cocktail protein loadings, increases in glucose release were not observed. Results indicate that synergism might occur among these additives and cellulase and xylanases. The use of these supplements, besides depending on factors such as pretreatment method of sugarcane bagasse, enzymatic cocktails composition, and solid and protein loadings, may not always lead to positive effects on the hydrolysis of lignocellulosic material, making it necessary further statistical studies, according to process conditions. 相似文献
62.
Larissa Canilha Walter Carvalho Maria das Graças de Almeida Felipe João Batista de Almeida e Silva Marco Giulietti 《Applied biochemistry and biotechnology》2010,161(1-8):84-92
The objective of this study was to evaluate the ethanol production from the sugars contained in the sugarcane bagasse hemicellulosic hydrolysate with the yeast Pichia stipitis DSM 3651. The fermentations were carried out in 250-mL Erlenmeyers with 100 mL of medium incubated at 200 rpm and 30 °C for 120 h. The medium was composed by raw (non-detoxified) hydrolysate or by hydrolysates detoxified by pH alteration followed by active charcoal adsorption or by adsorption into ion-exchange resins, all of them supplemented with yeast extract (3 g/L), malt extract (3 g/L), and peptone (5 g/L). The initial concentration of cells was 3 g/L. According to the results, the detoxification procedures removed inhibitory compounds from the hemicellulosic hydrolysate and, thus, improved the bioconversion of the sugars into ethanol. The fermentation using the non-detoxified hydrolysate led to 4.9 g/L ethanol in 120 h, with a yield of 0.20 g/g and a productivity of 0.04 g L?1 h?1. The detoxification by pH alteration and active charcoal adsorption led to 6.1 g/L ethanol in 48 h, with a yield of 0.30 g/g and a productivity of 0.13 g L?1 h?1. The detoxification by adsorption into ion-exchange resins, in turn, provided 7.5 g/L ethanol in 48 h, with a yield of 0.30 g/g and a productivity of 0.16 g L?1 h?1. 相似文献
63.
It is shown that a vorticity, constructed from the spin field of a quantum spinning plasma, combines with the classical generalized vorticity (representing the magnetic and the velocity fields) to yield a new grand generalized vorticity that obeys the standard vortex dynamics. Expressions for the quantum or spin vorticity and for the resulting generalized helicity invariant are derived. Reduction of the rather complex spinning quantum system to a well known and highly investigated classical form opens familiar channels for the delineation of physics peculiar to dense plasmas spanning solid state to astrophysical objects. A simple example is worked out to show that the magnetics of a spinning plasma can be much richer than that of the corresponding classical system. 相似文献
64.
65.
Marlene Espinoza-Moraga Tania Petta Marco Vasquez-Vasquez V. Felipe Laurie Luis A.B. Moraes Leonardo Silva Santos 《Tetrahedron: Asymmetry》2010,21(16):1988-1992
β-Carboline imine reductions mediated by Saccharomyces bayanus have been described achieving moderate to good enantiomeric excesses of the amine products. The enantiomeric excesses of the bioreduction showed a dependence on the imine substituents. Compounds presenting C1–C11 aliphatic substituent groups afforded amines with an (S)-configuration, whereas C15 and higher aliphatic- and aromatic-substituted β-carboline imines achieved inversion of the configuration in the final (R)-2 amine products. Based on this data, a model for the Saccharomyces reduction is proposed. 相似文献
66.
José Felipe Voloch 《Journal of Geometry》1990,38(1-2):198-200
67.
Igor E. Shparlinski José Felipe Voloch 《Bulletin of the Brazilian Mathematical Society》2008,39(3):417-425
We view an algebraic curve over ℚ as providing a one-parameter family of number fields and obtain bounds for the average value
of some standard prime ideal counting functions over these families which are better than averaging the standard estimates
for these functions.
相似文献
68.
Synthesis of Novel Ethyl (substituted)phenyl‐4‐oxothiazolidin‐3‐yl)‐1‐ethyl‐4‐oxo‐1,4‐dihydroquinoline‐3‐Carboxylates as Potential Anticancer Agents 下载免费PDF全文
Victor Facchinetti Felipe A. Guimarães Marcus Vinícius N. de Souza Claudia Regina B. Gomes Maria Cecília B. V. de Souza James L. Wardell Solange M. S. V. Wardell Thatyana R. A. Vasconcelos 《Journal of heterocyclic chemistry》2015,52(4):1245-1252
A series of ethyl (substituted)phenyl‐4‐oxothiazolidin‐3‐yl)‐1‐ethyl‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylates ( 7a , 7b , 7c , 7d , 7e , 7f , 7g ) has been prepared from reactions between aminoquinolones 6 with arenealdehydes and mercaptoacetic acid. The critical intermediates, 6 a and 6b , were obtained from appropriate amines by a sequence of steps involving (i) reaction with diethylethoxymethylenemalonate, (ii) thermal cyclization in diphenyl ether, (iii) ethylation and (iv) Pd/C catalyzed reduction. New compounds 7a , 7b , 7c , 7d , 7e , 7f , 7g were fully identified and characterized by NMR (1H and 13C) and specifically for 7d by X‐ray crystallography. Compounds 7b , 7c , 7d , 7e , 7f were found not to exhibit activity at 10 uM concentrations against gastric ascitis (AGP‐01), gastric adenocarcinoma kind intestinal (ACP‐02), colon (HCT‐116) and murine melanome (B16F10) cancer cells. However, none exhibited cytotoxicity against normal cells human fibroblast (MRC‐5), murine fibroblast (NIH3T3) and normal human melanocyte (Melan‐A). 相似文献
69.
Photosensitizing Activity of Endogenous Eye Lens Chromophores: An Attempt to Unravel Their Contributions to Photo‐Aging and Cataract Disease 下载免费PDF全文
UVA‐visible light has been proposed as a risk factor in the photo‐aging of the human eye lens, as well as in the etiology of cataract disease. There is accumulating evidence indicating that photosensitizing reactions mediated by endogenous chromophores, which are generated during human eye lens aging, can play an important role in the generation of these processes. These reactions can lead to protein impairment by inducing non‐enzymatic post‐translational modifications such as protein oxidation and crosslinking. Although numerous chromophores have been characterized as both bound to human eye lens proteins and as unbound low‐molecular‐mass compounds, their contribution to eye lens photoaging and cataract disease is not completely understood. In this article we discuss the photochemical contribution of UV‐filters derived from tryptophan catabolism and advanced glycation end products (AGEs) to human eye lens aging and cataract disease. We also discuss the recently described photosensitizing capacity of chromophores derived from newly discovered glucose and ascorbate degradation as a parallel pathway to their role in AGEs generation. 相似文献
70.
Combined Experimental and Computational Investigations of Rhodium‐Catalysed CH Functionalisation of Pyrazoles with Alkenes 下载免费PDF全文
Dr. Andrés G. Algarra Prof. David L. Davies Dr. Qudsia Khamker Prof. Stuart A. Macgregor Dr. Claire L. McMullin Kuldip Singh Dr. Barbara Villa‐Marcos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):3087-3096
Detailed experimental and computational studies have been carried out on the oxidative coupling of the alkenes C2H3Y (Y=CO2Me ( a ), Ph ( b ), C(O)Me ( c )) with 3‐aryl‐5‐R‐pyrazoles (R=Me ( 1 a ), Ph ( 1 b ), CF3 ( 1 c )) using a [Rh(MeCN)3Cp*][PF6]2/Cu(OAc)2 ? H2O catalyst system. In the reaction of methyl acrylate with 1 a , up to five products ( 2 aa – 6 aa ) were formed, including the trans monovinyl product, either complexed within a novel CuI dimer ( 2 aa ) or as the free species ( 3 aa ), and a divinyl species ( 6 aa ); both 3 aa and 6 aa underwent cyclisation by an aza‐Michael reaction to give fused heterocycles 4 aa and 5 aa , respectively. With styrene, only trans mono‐ and divinylation products were observed, whereas with methyl vinyl ketone, a stronger Michael acceptor, only cyclised oxidative coupling products were formed. Density functional theory calculations were performed to characterise the different migratory insertion and β‐H transfer steps implicated in the reactions of 1 a with methyl acrylate and styrene. The calculations showed a clear kinetic preference for 2,1‐insertion and the formation of trans vinyl products, consistent with the experimental results. 相似文献