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排序方式: 共有2245条查询结果,搜索用时 468 毫秒
151.
Nivia Maria Streit Luisa Helena Rychecki Hecktheuer Marta Weber do Canto Carlos Augusto Mallmann Letícia Streck Thaylise Vey Parodi Liana Pedrolo Canterle 《Food chemistry》2007,102(3):560-564
Erva-mate (Ilex paraguariensis St. Hil.) is a native species from temperate regions of South America, such as Brazil, Paraguay, and Argentina, that is consumed as a beverage known as mate. The objective of this research was to determine the content of caffeic acid, catechin, chlorogenic acid, caffeine, and gallic acid in mate to explain their influence in beverage taste and sensory differences between native and reforested plants, as well as between beverages from plants of different regions of Brazil (Santa Catarina and Rio Grande do Sul states). Compounds were determined by HPLC and results were related to a sensory evaluation performed by trained tasters. Tasters considered the beverage from reforested plants to be more bitter than the beverage from native plants. Beverages from reforested plants had significantly higher caffeic acid and lower catechin, chlorogenic acid, caffeine, and gallic acid content than native plants. Beverages from plants of Santa Catarina state had significantly higher catechin, caffeine, and gallic acid content than plants from Rio Grande do Sul state. 相似文献
152.
Amparo Galan Anna Padros Marta Arambarri Silvia Martin 《Journal of Automated Methods and Management in Chemistry》1998,20(1):23-26
A spectrometric method for the determination of L-carnitine has
been developed based on the reaction of the 5,5′ dithiobis-(2-nitrobenzoic) acid (DTNB) and adapted to a Technicon RA-2000 automatic analyser Química Farmacéutica Bayer, S.A.). The detection limit of the method is 13.2 μmol/l, with a measurement interval ranging from 30 to 320 μmoll1. Imprecision and accuracy are good even at levels close to the detection limit (coeffcient of variation of 5.4% for within-run imprecision for a concentration of 35 μmol/l). A good correlation was observed between the method studied and the radiometric method. The method evaluated has suffcient analytical sensitivity to diagnose carnitine deficiencies. The short time period required for sample processing (30 samples in 40min), the simple methodology and apparatus, the ease of personnel training and the low cost of the reagents make this method a good alternative to the classical
radiometric method for evaluating serum L-carnitine in clinical laboratories without radioactive installations. 相似文献
153.
Antonio Sánchez‐Díaz Marta Izquierdo Salvatore Filippone Nazario Martin Emilio Palomares 《Advanced functional materials》2010,20(16):2695-2700
Organic solar cells made using a blend of DPM12 and P3HT are studied. The results show that higher Voc can be obtained when using DPM12 in comparison to the usual mono‐substituted PCBM electron acceptor. Moreover, better device performances are also registered when the cells are irradiated with sun‐simulated light of 10–50 mW cm?2 intensity. Electrochemical and time‐resolved spectroscopic measurements are compared for both devices and a 100‐mV shift in the density of states (DOS) is observed for DPM12/P3HT devices with respect to PCBM/P3HT solar cells and slow polaron‐recombination dynamics are found for the DPM12/P3HT devices. These observations can be directly correlated with the observed increase in Voc, which is in contrast with previous results that correlated the higher Voc with different ideality factors obtained using dark‐diode measurements. The origin for the shift in the DOS can be correlated to the crystallinity of the blend that is influenced by the properties of the included fullerene. 相似文献
154.
Effect of the long-term intake of an egg white hydrolysate on the oxidative status and blood lipid profile of spontaneously hypertensive rats 总被引:1,自引:0,他引:1
María A. Manso Marta Miguel Jeanne Even Rosario Hernández Amaya Aleixandre Rosina López-Fandiño 《Food chemistry》2008
This paper examines the effects of the long-term consumption of egg white hydrolysed with pepsin (hEW) on the antioxidant status and lipid profile of spontaneously hypertensive rats (SHR). The antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) and the oxidative status by the malon-dialdehyde (MDA) assay. The lipid profile was analysed spectrophotometrically. The radical-scavenging capacity of the plasma was increased and the MDA concentration in the aorta was decreased in the SHR treated with 0.5 g/kg/day of hEW. Our findings indicate that hEW played an important role in antioxidative defence of SHR and exerted a beneficial effect on the lipid profile, lowering triglycerides and total cholesterol without changing HDL levels. Therefore, hEW may be useful to prevent or reverse abnormalities associated with the metabolic syndrome and its complications, such as hypertension, oxidative stress and hyperlipidemia. 相似文献
155.
Coulson Seana; Federmeier Kara D.; Van Petten Cyma; Kutas Marta 《Canadian Metallurgical Quarterly》2005,31(1):129
Researchers using lateralized stimuli have suggested that the left hemisphere is sensitive to sentence-level context, whereas the right hemisphere (RH) primarily processes word-level meaning. The authors investigated this message-blind RH model by measuring associative priming with event-related brain potentials (ERPs). For word pairs in isolation, associated words elicited more positive ERPs than unassociated words with similar magnitudes and onset latencies in both visual fields. Embedded in sentences, these same pairs showed large sentential context effects in both fields. Small effects of association were observed, confined to incongruous sentences after right visual hemifield presentation but present for both congruous and incongruous sentences after left visual hemifield presentation. Results do not support the message-blind RH model but do suggest hemispheric asymmetries in the use of word and sentence context during real-time processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
156.
Carina A. Emilio Raquel Gettar Marta I. Litter 《Journal of Applied Electrochemistry》2005,35(7-8):733-740
TiO2-heterogeneous photocatalysis of nitrilotriacetic acid (NTA) at pH 2.5 was studied to establish the kinetic regime and the
reaction mechanism. Pure Degussa P-25 and Hombikat UV100 commercial samples were compared. A Langmuirian behavior was observed
over P-25. Platinization of the Hombikat sample (0.5 wt.%) caused an important increase on the photocatalytic rate with a
change in the kinetics from zero order in the pure precursors to first order in the platinized sample. The nature of the intermediates
and their evolution with time were compared on all systems. Glycine, iminodiacetic and oxamic acids have been identified in
different proportions, together with ammonium and glycolic acid, depending on the catalyst used. The rapid depletion of NTA
was not accompanied by a corresponding total organic carbon (TOC) reduction, but 84% of TOC decrease was obtained on P25 after
24 h, a very reasonable result for refractory compounds. A detailed mechanism is proposed for the photocatalytic reaction,
suggested to be the same over the three catalysts here tested. 相似文献
157.
Bustos and Yohai proposed a class of robust estimates for autoregressive moving-average (ARMA) models based on residual autocovariances (RA estimates). In this paper an affine equivariant generalization of the RA estimates for vector ARMA processes is given. These estimates are asymptotically normal and, when the innovations have an elliptical distribution, their asymptotic covariance matrix differs only by a scalar factor from the covariance matrix corresponding to the maximum likelihood estimate. A Monte Carlo study confirms that the RA estimates are efficient under normal errors and robust when the sample contains outliers. A robust multivariate goodness-of-fit test based on the RA estimates is also obtained. 相似文献
158.
Redesigning an assembly line through lean manufacturing tools 总被引:1,自引:1,他引:0
Roberto Álvarez Roque Calvo Marta M. Peña Rosario Domingo 《The International Journal of Advanced Manufacturing Technology》2009,43(9-10):949-958
The implementation of a lean manufacturing strategy represents a robust contribution to the phase sequence that leads to operational excellence and the continuous improvement through the elimination of nonvalue-added activities. Therefore, lean practices contribute substantially to plant operational performance. This paper studies the use of value stream mapping (VSM) as a tool in lean manufacturing implementation and a framework of improvement activities, in particular for an efficient introduction of kanban and milkrun techniques. A case study illustrates VSM use, as well as kanban and milkrun systems application on an assembly line. Finally, the results obtained show the path of improvement, measured through the lean rate (LR) and dock-to-dock time (DtD). 相似文献
159.
Vanesa Palau Bramasta Nugraha David Benito Julio Pascual Maximilian Y. Emmert Simon P. Hoerstrup Marta Riera Maria Jos Soler 《International journal of molecular sciences》2021,22(11)
ADAM17 is a disintegrin and metalloproteinase capable of cleaving the ectodomains of a diverse variety of molecules including TNF-α, TGF-α, L-selectin, and ACE2. We have previously demonstrated that renal ADAM17 is upregulated in diabetic mice. The role of endothelial (eAdam17) and proximal tubular (tAdam17) Adam17 deletion in renal histology, modulation of the renin angiotensin system (RAS), renal inflammation, and fibrosis was studied in a mouse model of type 1 Diabetes Mellitus. Moreover, the effect of Adam17 deletion in an in vitro 3D cell culture from human proximal tubular cells under high glucose conditions was evaluated. eAdam17 deletion attenuates renal fibrosis and inflammation, whereas tAdam17 deletion decreases podocyte loss, attenuates the RAS, and decreases macrophage infiltration, α-SMA and collagen accumulation. The 3D in vitro cell culture reinforced the findings obtained in tAdam17KO mice with decreased fibrosis in the Adam17 knockout spheroids. In conclusion, Adam17 deletion either in the endothelial or the tubular cells mitigates kidney injury in the diabetic mice by targeting different pathways. The manipulation of Adam17 should be considered as a therapeutic strategy for treating DN. 相似文献
160.