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排序方式: 共有515条查询结果,搜索用时 15 毫秒
91.
Rogério A. Saraiva Edinardo F. F. Matias Henrique D. M. Coutinho José G. M. Costa Heloísa Helena F. Souza Cícera Norma Fernandes João B. T. Rocha Irwin R. A. Menezes 《European Journal of Lipid Science and Technology》2011,113(8):967-972
The oil obtained from the Caryocar coriaceum Wittm. (pequi) fruit pulp (C. coriaceum fixed oil – CCFO), rich in fatty acids, has been secularly employed by traditional medicine in the treatment of respiratory affections, skin inflammation, and wounds. These observations encouraged us to investigate the antimicrobial activity of CCFO and to investigate its effect in combination with aminoglycosides. The minimum inhibitory concentration (MIC) of CCFO alone and associated with aminoglycosides against Escherichia coli and Staphylococcus aureus strains were determined using microdilution assay. CCFO alone had a MIC of 512 µg/mL against E. coli and S. aureus resistant strains. Combining the CCFO with aminoglycosides reduced the MIC of aminoglycosides against the resistant strains of E. coli and S. aureus. The results obtained indicate that CCFO displays a significant synergistic antibiotic effect when combined with aminoglycosides, demonstrating that the oil constituents (fatty acids) may act as potentiators of the antibiotic activity of aminoglycosides. These properties make CCFO oil an interesting alternative as a remedy or nutraceutical against multiresistant bacteria, preventing the development of resistance by these microorganisms. Practical applications: This article demonstrates the capacity of the C. coriaceum oil to enhance the antibiotic activity of aminoglycosides. This activity could represent a new way to combat the growing bacterial resistance to antibiotics, an important problem of public health. 相似文献
92.
Julia Glaum Hugh Simons Matias Acosta Mark Hoffman 《Journal of the American Ceramic Society》2013,96(9):2881-2886
This article details the influence of zirconium doping on the piezoelectric properties and relaxor characteristics of 94(Bi1/2Na1/2)TiO3–6Ba(ZrxTi1?x)O3 (BNT–6BZT) bulk ceramics. Neutron diffraction measurements of BNT–6BZT doped with 0%–15% Zr revealed an electric‐field‐induced transition of the average crystal structure from pseudo‐cubic to rhombohedral/tetragonal symmetries across the entire compositional range. The addition of Zr up to 10% stabilizes this transition, resulting in saturated polarization hysteresis loops with a maximum polarization of 40 μC/cm2 at 5.5 kV/mm, while corresponding strain hysteresis measurements yield a maximum strain of 0.3%. With further Zr addition, the ferroelectric order is progressively destabilized and typical relaxor characteristics such as double peaks in the current density loops are observed. In the strain hysteresis, this destabilization leads to an increase of the maximum strain by 0.05%. These changes to the physical behavior caused by Zr addition are consistent with a reduction of the transition temperature TF‐R, above which the field‐induced transformation from the relaxor to ferroelectric state becomes reversible. 相似文献
93.
Optical fiber gas sensor based on self-assembled gratings 总被引:3,自引:0,他引:3
Arregui F.J. Claus R.O. Cooper K.L. Fernandez-Valdivielso C. Matias I.R. 《Lightwave Technology, Journal of》2001,19(12):1932-1937
The electrostatic self-assembled monolayer synthesis process is used to fabricate gas sensors by building up grating sensor elements on the ends of multimode optical fibers. These novel sensors can be designed to operate in the transmission windows of standard optical fibers and implemented using specific reference wavelengths to normalize the output signals. Experimental results for such sensors designed to detect dichloromethane gas are presented 相似文献
94.
Pillared clay and zirconia-based monolithic catalysts for selective catalytic reduction of nitric oxide by methane 总被引:3,自引:0,他引:3
A. Bahamonde F. Mohino M. Rebollar M. Yates P. Avila S. Mendioroz 《Catalysis Today》2001,69(1-4):233-239
New monolithic catalysts based on zirconia and pillared clays (PILC) have been studied for NOx removal by CH4 in the presence of oxygen. A comparative study of the influence of ZrO2 from various commercial sources for the system Pd–ZrO2 and the effect of the noble metal chosen for the system NM–PILC was carried out, trying to correlate the catalytic activity with the physico-chemical properties of these catalysts. The obtained results indicate that structure and surface acidity of the support plays an important role on the selectivity to NOx reduction, although properties such as the surface area or pore volume could also determine the overall activity of the monolithic catalysts. 相似文献
95.
Matias Ståhle Tuomas Ahola Miia Martinsuo 《International Journal of Project Management》2019,37(1):145-160
The delivery of integrated solutions calls for effective integration across the functional interfaces of the project-based firm (PBF) throughout the solution's life cycle. We scrutinize cross-functional integration in a triadic setting involving the PBF's sales, project operations, and services functions by focusing on the flow of customer information (information from and about customers) across three functional interfaces. Drawing on a qualitative case study, we develop a categorization consisting of four distinct types of integration mechanisms: meetings, IT systems, personal involvement, and processes and rules. Our results show that in the focal PBF, customer information flows are strongest in the sales–project operations interface and weakest in the sales–services interface. Furthermore, sales and services functions were found to rely predominantly on personal involvement mechanisms in transferring customer information. Our results highlight the need to integrate and manage customer information flows, especially between the sales–services interface, when delivering integrated solutions. 相似文献
96.
AbstractWe describe a methodology able to extract the regimes of operation from condensing heat exchanger data. The methodology applies a Gaussian mixtures clustering algorithm to determine the number of groups directly from the data, and a maximum likelihood decision rule to classify such data into these clusters. Published measurements visually classified as dry-surface, dropwise condensation, and film condensation, are used to illustrate the applicability of the classification technique. Since some results from the algorithmic and visual classifications differ, the second part presents an independent evaluation of the allocation process by a procedure based on artificial neural networks (ANNs) and a variant of cross-validation. Results from the ANN approach to the same data show remarkable agreement with the clustering technique confirming that an algorithmic classification of complex physical phenomena is not only possible but also accurate, and represents an excellent alternative to typical visual-based procedures for the analysis of thermal and other systems. 相似文献
97.
Ana Rato Luís F. Pereira Sandra Joaquim Romina Gomes Cláudia Afonso Carlos Cardoso Jorge Machado José F. M. Gonçalves Paulo Vaz-Pires Leonardo J. Magnoni Ana M. Matias Domitília Matias Narcisa M. Bandarra Rodrigo O. A. Ozório 《Lipids》2019,54(9):531-542
The fatty acid (FA) profile of oysters generally reflects the dietary FA composition. Moreover, incorporation of FA into tissues is modulated by various metabolic factors, and final composition will depend upon the dietary sources, cumulative intake, and oysters' development stage. Thus, the aim of this study was to assess the impact of dietary incorporation of seaweed (SW) Ulva rigida, in replacement of traditional microalgae diet, on the FA composition of Pacific oysters Crassostrea gigas, during broodstock conditioning. The dietary conditioning consisted of direct replacement of microalgae (33% Tisochrysis lutea, 50.25% Skeletonema costatum, and 16.75% Chaetoceros calcitrans) by SW at four different substitution levels (0%, 25%, 50%, and 100% diet). The dietary docosahexaenoic acid (DHA) (22:6n-3) and eicosapentaenoic acid (EPA) (20:5n-3) contents showed a positive correlation with the dietary microalgae level. During the trial, oysters fed with higher percentages of microalgae revealed a depletion of DHA and accumulation of EPA. The 100% SW caused a significant reduction in oxygen consumption and, consequently, in the standard metabolic rate. Based on these results, a partial substitution of up to 25% of dietary microalgae seems to be a suitable alternative, because it elicited similar results to the commercial 100% microalgae diet. 相似文献
98.
99.
Larissa Braga Bueno-Borges Grasiela Cristina Pereira dos Santos Severino Matias de Alencar Marisa Aparecida Bismara Regitano-d'Arce 《Journal of the American Oil Chemists' Society》2019,96(12):1379-1388
Waste cooking oils (WCO) can be used as feedstock for biodiesel (fatty acid ethyl or methyl esters—FAEE or FAME) production. Their usual high acidity, high moisture, and low stability can impair the reaction yield and generate a low-quality biodiesel. Here, we performed liquid–liquid washings using WCO and ethanol-based solvents with the goal of generating oil-rich miscella as FAEE feedstocks with a higher quality than WCO. Three different solvents were evaluated: 99% ethanol, 95% ethanol, and the soybean oil extraction ethanolic phase (SEP), a by-product with immense unexplored antioxidant potential obtained by extracting soybean oil using ethanol. Washings were performed in a 1000 mL flat-bottom flask at 78.1 °C, using a 1:2 (w/v) oil/solvent ratio, under magnetic stirring (1200 rpm) for 10 min. Ethyl esters were prepared via homogeneous alkali transesterification using WCO and oil-rich miscella as feedstocks. Treatments reduced the acid value by 40–61% and the peroxide value by 15–50%. Improvements in feedstock quality generated 24–54% higher biodiesel yields. The oil-rich phase produced with SEP was 15% more resistant to oxidation than WCO. This was attributed to the transference of isoflavones from the SEP. However, biodiesel from treated samples presented equal or lower oxidative stability than FAEE from WCO. High-performance liquid chromatography (HPLC) analysis showed that no isoflavones remained in biodiesel after purification. Pretreatment of WCO with ethanol-based extracts such as the SEP has great potential to improve WCO quality for biodiesel production as it can be a source of plant-based antioxidants. 相似文献
100.
L Gil del Valle D Gebru W/Michael A Martinez Rodríguez R Tápanes Peraza F Ramos J Pérez Avila 《Canadian Metallurgical Quarterly》1997,698(1-2):312-316
A sensitive gas chromatographic method for the quantitative determination of the new antibacterial and antifungal drug G1, 1-(5-bromofuran-2-yl)-2-bromo-2-nitroethene, has been optimized. The method involves a fast and single extraction step from spiked serum and urine samples. The G1 drug was quantified using an internal standard method and by means of a nitrogen-selective detector. The results are statistically significant and show that mean levels of G1 as low as 1 microg ml(-1) can be measured accurately. 相似文献