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921.
Antibacterial activity of roselle calyx extracts,sodium hypochlorite,colloidal silver and acetic acid against multidrug‐resistant salmonella serotypes isolated from coriander 下载免费PDF全文
922.
Oxidation of sulfide under aerobic conditions by biofilms grown on municipal wastewater in 6 identical pipe reactors was investigated. The biofilms were grown at pH 7.6 and temperatures of 20 and 25 degrees C under aerobic-anaerobic transient conditions with pulse dosing of sulfide in the bulk water. The pulse dosing of sulfide served to simulate conditions in a gravity sewer located downstream of a pressure main. During growth of the biofilms, sulfide was pulse dosed in concentrations of 0, 0.5, 2.0 and 5.0 g Sm(-3) with a frequency of 1h(-1). Based on a series of batch experiments, kinetics and stoichiometry of sulfide oxidation by the sewer biofilms was investigated and a rate equation and a stoichiometric constant proposed. Sulfide oxidation kinetics was significantly faster for biofilms grown at sulfide loadings of 0.5, 2.0 and 5.0 g Sm(-3)h(-1) than for biofilms grown in the absence of sulfide. However, the kinetics of sulfide oxidation was relatively constant for biofilms grown at sulfide loadings above 0.5 g Sm(-3)h(-1). Mass balance calculations of dissolved oxygen and sulfur compounds suggested the oxidation product to be elemental sulfur. Further oxidation of elemental sulfur could not be documented. 相似文献
923.
Enrique García Jesús Ureña Juan J. García Daniel Ruiz María C. Pérez Juan C. García 《International Journal of Circuit Theory and Applications》2014,42(10):1006-1015
In this paper, a digital filter for the generation/correlation of binary Golay pairs of sequences of length 2N · 10M · 26P (N, M and P are non‐negative integers) is proposed. It is carried out by means of a novel Golay kernel 26 decomposition, also introduced in this paper, combined with building blocks of Golay kernels 2 and 10, presented in previous works. The proposed filter has a similar architecture to the digital filter for the generation/correlation of Golay multilevel pairs of sequences, where the parameters at intermediate stages have to be adjusted to obtain Golay binary pairs of sequences in the final stage. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
924.
Electrical conductivity properties of expanded graphite–polycarbonatediol polyurethane composites 下载免费PDF全文
Belen Redondo‐Foj Pilar Ortiz‐Serna Marta Carsí María Jesús Sanchis Mario Culebras Clara María Gómez Andrés Cantarero 《Polymer International》2015,64(2):284-292
Conductive polymer composites of segmented polycarbonatediol polyurethane and expanded graphite (EG) have been synthesized with different amounts of EG conductive filler (from 0 to 50 wt%). SEM, X‐ray diffraction measurements, Fourier transform infrared and Raman spectroscopies demonstrated a homogeneous dispersion of the EG filler in the matrix. The dielectric permittivity of the composites showed an insulator to conductor percolation transition with increase in EG content. Significant changes in the dielectric permittivity take place when the weight fraction of EG is in the range 20–30 wt%. Special attention has been paid to the dependence of the conductivity on frequency, temperature and EG content. The addition of EG to the matrix causes a dramatic increase in the electrical conductivity of 10 orders of magnitude, which is an indication of percolative behavior. A percolation threshold of ca 30 wt% was evaluated by using the scaling law of percolation theory. © 2014 Society of Chemical Industry 相似文献
925.
Degradability of extruded polyethylene/chitosan blends compatibilized with polyethylene‐graft‐maleic anhydride under natural weathering 下载免费PDF全文
Dora Evelia Rodríguez‐Félix Jesús Manuel Quiroz‐Castillo Heriberto Grijalva‐Monteverde Teresa del Castillo‐Castro Silvia Elena Burruel‐Ibarra Francisco Rodríguez‐Félix Tomás Madera‐Santana Rafael Enrique Cabanillas Pedro Jesús Herrera‐Franco 《应用聚合物科学杂志》2014,131(22)
The impact of chitosan on the natural weathering behavior of two blends obtained by mixing either polyethylene (PE) with chitosan or PE, chitosan and polyethylene‐graft‐maleic anhydride (PEgMA) as a compatibilizer is analyzed. In order to follow the weathering behavior of both the uncompatibilized and compatibilized systems, the blend films are exposed to outdoor conditions for 6 months. The weathering behavior of the films is monitored by mechanical tests, spectroscopic Fourier transform infrared, and morphological analyses at different weathering periods of time. The presence of chitosan in the blends accelerates significantly the degradation of the films. Apparently, PEgMA also accelerates the photo‐oxidation rate of the films. This behavior appears to be related to the photo‐oxidative instability of maleic anhydride, and also to the better dispersion of chitosan in the PE matrix, which is due to the interactions in the PE/chitosan interface caused by the addition of the compatibilizer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41045. 相似文献
926.
Structure‐Based Design of New KSP‐Eg5 Inhibitors Assisted by a Targeted Multicomponent Reaction 下载免费PDF全文
Carlos Carbajales Dr. Miguel Ángel Prado Dr. Hugo Gutiérrez‐de‐Terán Ángel Cores Dr. Jhonny Azuaje Dr. Silvia Novio Prof. María Jesús Nuñez Dr. Belén Fernández‐García Prof. Eddy Sotelo Prof. Xerardo García‐Mera Prof. Pedro Sánchez‐Lazo Prof. Manuel Freire‐Garabal Prof. Alberto Coelho 《Chembiochem : a European journal of chemical biology》2014,15(10):1471-1480
An integrated multidisciplinary approach that combined structure‐based drug design, multicomponent reaction synthetic approaches and functional characterization in enzymatic and cell assays led to the discovery of new kinesin spindle protein (KSP) inhibitors with antiproliferative activity. A focused library of new benzimidazoles obtained by a Ugi+Boc removal/cyclization reaction sequence generated low‐micromolar‐range KSP inhibitors as promising anticancer prototypes. The design and functional studies of the new chemotypes were assessed by computational modeling and molecular biology techniques. The most active compounds— 20 (IC50=1.49 μM , EC50=3.63 μM ) and 22 (IC50=1.37 μM , EC50=6.90 μM )—were synthesized with high efficiency by taking advantage of the multicomponent reactions. 相似文献
927.
Even though worldwide production of rabbit meat is over 1,000,000ton, little information is available on rabbit meat microbiology. This paper reports on the microflora developing on chill-stored rabbit carcasses. Four different lots of 24h post-mortem rabbit carcasses dressed and kept at 0°C in a medium-size abattoir were collected and evaluated for sensory, physicochemical and microbiological changes during aerobic storage at 3±1°C. Mean initial pH value (pH(24)), extract-release volume (ERV) and lactate content of Biceps femoris muscle, were 6.26±0.20, 13.50±3.50ml and 0.70±0.07%, respectively. As with other muscle foods kept chilled in air, pH increased and ERV and lactate decreased as storage progressed. Initial levels (logcfu/g) of aerobes (APC), psychrotrophic flora, Pseudomonas spp., Brochothrix thermosphacta, lactic acid bacteria, Enterobacteriaceae and yeasts were 4.76±0.31, 4.81±0.81, 3.39±1.12, 2.01±0.92, 2.76±0.51, 0.49±0.45 and 3.46±0.32, respectively. Pseudomonads, most of them fluorescent, and to a lesser extent B. thermosphacta and yeasts grew faster than the remaining microorganisms and became predominant at the end of the shelf life. Carcasses spoiled when mean APC, psychrotrophic and pseudomonads numbers were ca. 8logcfu/g, their mean shelf life being estimated at 6.8 days. A lot of DFD-like rabbit carcasses, with higher pH and lower ERV values but similar microbial loads to normal meat, developed a strong putrid odour after 4 days. 相似文献
928.
Roberto Yáñez-Macías Jorge E. Rivera-Salinas Silvia Solís-Rosales Daniel Orduña-Altamirano David Ruíz-Mendoza Adán Herrera-Guerrero Jesús Lara-Sanchez Pablo González-Morones Zureima García-Hernández Ernesto Hernández-Hernández Karla M. Gregorio-Jáuregui 《应用聚合物科学杂志》2021,138(27):50648
Glass fiber-reinforced Nylon-6 syntactic foams (GRSF) were fabricated by melt mixing, adding silane-modified hollow glass microspheres (HGMf) at 5, 10, 15, and 20 wt% and an impact modifier at 15 wt. Tensile test results showed that the foam's strength increased with the addition of HGMs but started to decrease when the volume fraction of the spheres was higher than 18 vol% (10 wt%). To elucidate the reinforcement mechanism, a numerical simulation of GRSF was carried out. It revealed that HGMs progressively become the reinforcement phase of GRSFs, as their volume fraction increased due to the load transfer occurring more readily in the HGMs than the fiber, which is expected to be the reinforcement. Hence, for a desired weight-strength ratio, thicker walls are necessary to delay the elastic relaxation of the microspheres and the impairing of the composite as a whole in the context of strength. HGMs with relative wall thickness τ = 0.04 produce an impairing on Young's modulus, if the volume fraction of microspheres is exceeded than 18 vol% because the microspheres are not able to endure increased loads. In addition, a significant reduction of the density was observed by up to 12% in the GRSFs with 30 wt% of both fibers and HGMs. The insight gained of GRSFs role and the numerical simulation achieved through this work, is a significant step toward developing applications of these lightweight materials, since they show good combination of strength, toughness, density, and thermal insulation performance, which can be useful in the automotive, aeronautical and sports industries. 相似文献
929.
Cultivar discrimination and prediction of mixtures of Tunisian extra virgin olive oils by FTIR 下载免费PDF全文
930.
Jesús Blázquez‐Ruiz Vicente P. Guerrero‐Bote Félix Moya‐Anegón 《Comprehensive Reviews in Food Science and Food Safety》2016,15(6):1040-1055
This article describes an analysis of keywords which was aimed at revealing publication patterns in the field of Food Science (FS) during the last decade, including the temporal evolution of its different research lines. To this end, the records of the specific subject area of FS were 1st retrieved from Scopus, and then their keywords were processed to resolve the obvious problems of synonymy and to limit the study to those most frequently used. These keywords were grouped into thematic clusters based on a scientometric technique known as co‐word analysis. The structure of the clusters, their scientific impact, and their temporal evolution were then analyzed. This type of analysis is of great interest for all researchers in FS—for new researchers because they can form an objective vision of the subject based on the data from papers that have been published in the last decade, and for experienced researchers because they can contrast their own vision of the field with this objective overview. The results showed there to has been a clear increase in scientific production related to FS. This production had a structure corresponding to 5 major clusters which were themselves disaggregated into 18 2nd‐level clusters. The cluster that had received most attention was that corresponding to antioxidants in food, being the cluster with the greatest scientific impact and the greatest growth in the period. 相似文献