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61.
Highly selective enzymatic reductions of aldehydes to the corresponding alcohols was performed using an E. coli JM109 whole cell biocatalyst. A selective enzymatic method for the reduction of aldehydes could provide an eco-compatible alternative to chemical methods. The simplicity, fairly wide scope and the very high observed chemoselectivity of this approach are its most unique features. 相似文献
62.
Gervásio A. Degrazia Otávio C. Acevedo Silvana Maldaner Umberto Rizza 《Physica A》2010,389(24):5808-5813
The classical statistical diffusion theory and the binomial autocorrelation function are used to obtain a new formulation for the turbulence dissipation rate ε. The approach employs the Maclaurin series expansion of a logarithm function contained in the dispersion parameter formulation. The numerical coefficient of this new relation for ε is 100% larger than the numerical coefficient of the classical relation derived from the exponential autocorrelation function. A similar approach shows that the dispersion parameter obtained from the even exponential autocorrelation function does not result in a relation for ε and, therefore, is not suitable for application in dispersion models. In addition, a statistical comparison to experimental ground-level concentration data demonstrates that this newly derived relation for ε as well as other formulations for the turbulence dissipation rate are suitable for application in Lagrangian stochastic dispersion models. Therefore, the analysis shows that there is an uncertainty regarding the turbulence dissipation rate function form and the autocorrelation function form. 相似文献
63.
In this work we study properties of random graphs that are drawn uniformly at random from the class consisting of biconnected
outerplanar graphs, or equivalently dissections of large convex polygons. We obtain very sharp concentration results for the
number of vertices of any given degree, and for the number of induced copies of a given fixed graph. Our method gives similar
results for random graphs from the class of triangulations of convex polygons. 相似文献
64.
The IR spectra have been recorded in the solid state for the parent molecule, 6-(N-pyrrolyl)purine (1) and its N-9-and N-7-substituted derivatives: 9-and 7-(2-hydroxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (2 and 3), 9-and 7-(2-acetoxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (4 and 5), 9-and 7-(2,3-dihydroxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (6 and 7) as well as 9-and 7-(2,3-diacetoxyprop-1-yl)-6-(N-pyrrol-1-yl)purine (8 and 9). Analysis of the characteristic bands has proved to be useful in differentiating between N-9 and N-7 regioisomers. 相似文献
65.
Let K be a field of characteristic p > 0, let L be a restricted Lie algebra and let R be an associative K-algebra. It is shown that the various constructions in the literature of crossed product of R with u(L) are equivalent. We calculate explicit formulae relating the parameters involved and obtain a formula which hints at a noncommutative version of the Bell polynomials. 相似文献
66.
Molina FD Bertollo EM Assis CM Falleiros LR Campos SG Maniglia JV Taboga SR 《Micron (Oxford, England : 1993)》2008,39(7):910-914
Squamous cell carcinoma of the tongue is one of the most common head and neck cancer. Treatment in the early stages is still controversial. This study aims to correlate the apoptosis rate of primary tongue cancer with cervical node metastasis, found in the histopathological studies of specimens obtained from neck dissections or during clinical follow-up. Twenty patients, 65% males, mean age 64.5 years, without clinical evidence of cervical metastasis was included. Eighty-five percent were smokers and 40% were alcohol abusers. Mann-Whitney test was used for statistical analysis (p=0.05). Five patients with clinically occult cervical metastases had metastasis in the histopathological specimens (25%) occult metastasis. The mean apoptosis rate in patients without cervical metastasis was 9.43%. Twenty-five percent of the patients had occult cervical metastasis. High apoptosis rate in tongue cancer, even in the absence of palpable neck nodes, correlates with the presence of occult metastasis. 相似文献
67.
We consider the problem of sending a message from a sender to a receiver through an unreliable network by specifying in a protocol what each vertex is supposed to do if it receives the message from one of its neighbors. A protocol for routing a message in such a graph is finite if it never floods with an infinite number of copies of the message. The expected reliability of a given protocol is the probability that a message sent from reaches when the edges of the network fail independently with probability .We discuss, for given networks, the properties of finite protocols with maximum expected reliability in the case when is close to 0 or 1, and we describe networks for which no one protocol is optimal for all values of . In general, finding an optimal protocol for a given network and fixed probability is challenging and many open problems remain. 相似文献
68.
69.
A Stable Porphyrin Functionalized Graphite Electrode Used at the Oxygen Evolution Reaction Potential
Gianlorenzo Bussetti Roberto Bernasconi Claudia Filoni Luca Magagnin Alberto Bossi Franco Ciccacci Lamberto Duò 《Electroanalysis》2022,34(7):1227-1236
Many researches have been devoted to rechargeable power generators that can store (but also release) energy. This availability is ensured through (e. g.) the oxygen evolution reaction (OER). However, (i) large values of the overpotentials and (ii) a progressive detriment of the anode (graphite) electrode limit the ultimate device. In view of enhancing the electrode performances, graphite was protected by following different strategies, which oblige to follow precise preparation protocols. Here, we prove that a thin layer of free-base porphyrin molecules is able to protect the underneath graphite electrode from detriment even if many (about 100) electrochemical cycles are performed. 相似文献
70.
Silvana Alborés Paola Mora María José Bustamante María Pía Cerdeiras Laura Franco Fraguas 《Applied biochemistry and biotechnology》2014,172(4):2081-2090
A lectin was isolated from fruiting bodies of the mushroom Gymnopilus spectabilis (GSL) by ionic exchange chromatography. The lectin agglutinates mouse red cells exhibiting broad specificity towards several monosaccharides including the N-acetylneuraminic acid. Agglutination was also inhibited by the glycoproteins: fetuin, lactoferrin, and recombinant erythropoietin. GSL is a glycoprotein possessing 16 % of carbohydrates; the SDS-PAGE showed two bands with molecular mass of 52.1 and 64.4 kDa. Isoelectric focusing displayed microheterogeneity, with two bands at pIs 5.1 and 5.3. The lectin was stable between pH 2 and pH 8 while at pH 10, the agglutination decayed to 50 % of initial activity. Incubation at 40 and 80 °C led to 50 and 100 % loss in activity of the lectin, respectively. Synthesized GSL-Sepharose interacts with serum pregnant mare gonadotropin, and at least two subpopulations of this glycoprotein were separated. There was no interaction between transferrin and soluble GSL while a partial recognition was achieved with GSL-Sepharose. The terminal sialic acid seems to play an active role in modifying the interaction with GSL, depending if the lectin is in a soluble or immobilized form. The purified lectin inhibited in vitro the growth of Staphylococcus aureus and Aspergillus niger. 相似文献