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排序方式: 共有1114条查询结果,搜索用时 15 毫秒
981.
S Estrada-Parra A Nagaya E Serrano O Rodriguez V Santamaria R Ondarza R Chavez B Correa A Monges R Cabezas C Calva I Estrada-Garcia 《Canadian Metallurgical Quarterly》1998,20(10):521-535
Reactivation of varicella herpes virus (VHV), latent in individuals who have previously suffered varicella, gives rise to herpes zoster and in some cases leads to a sequela of post herpetic neuritis with severe pain which is refractory to analgesics. Many different antiviral agents have been tried without achieving satisfactory results. Of all the antiviral agents employed, acyclovir has been the most successful in reducing post herpetic pain. However acyclovir has not been as reliable as interferon alpha (IFN-alpha). We have previously looked into the use of transfer factor (TF) as a modulator of the immune system, specifically with respect to its effectiveness in the treatment of herpes zoster. In this work findings from a comparative clinical evaluation are presented. A double blind clinical trial of TF vs acyclovir was carried out in which 28 patients, presenting acute stage herpes zoster, were randomly assigned to either treatment group. Treatment was administered for seven days and the patients were subsequently submitted to daily clinical observation for an additional 14 days. An analogue visual scale was implemented in order to record pain and thereby served as the clinical parameter for scoring results. The group treated with TF was found to have a more favorable clinical course, P < or = 0.015. Laboratory tests to assess the immune profile of the patients were performed two days prior and 14 days after initial treatment. The results of these tests showed an increase in IFN-gamma levels, augmentation in the CD4+ cell population but not the percentage of T rosettes in the TF treated group. These parameters were however insignificantly modified in patients receiving acyclovir. Although TF treated patients showed an increase in CD4+ counts these cells remained below the levels for healthy individuals. The fact that IFN-gamma levels as well as the counts for CD4+ cells rose in the TF treated group and not in the acyclovir one is very significant and confirms the immunomodulating properties of TF. 相似文献
982.
JF López-Giménez G Mengod JM Palacios MT Vilaró 《Canadian Metallurgical Quarterly》1997,356(4):446-454
The recently developed 5-HT2A receptor selective antagonist [3H]MDL100,907 ((+/-)2,3-dimethoxyphenyl-1-[2-(4-piperidine)-methanol]) has been characterized as a radioligand for the autoradiographic visualization of these receptors. [3H]MDL100,907 binding to rat brain tissue sections was saturable, had sub-nanomolar affinity (Kd = 0.2-0.3 nM), and presented a pharmacological profile consistent with its binding to 5-HT2A receptors (rank order of affinity for [3H]MDL100,907-labelled receptors: MDL100,907 > spiperone > ketanserin > mesulergine). The distribution of receptors labelled by [3H]MDL100,907 was compared to the autoradiographical patterns obtained with [3H]Ketanserin, [3H]Mesulergine, and [3H]RP62203 (N-[3-[4-(4-fluorophenyl)piperazin-1-y1]propyl]-1,8-naphtalenes ultam) and to the distribution of 5-HT2A receptor mRNA as determined by in situ hybridization. As opposed to the other radioligands, [3H]MDL100,907 labelled a single population of sites (5-HT2A receptors) and presented extremely low levels of non-specific binding. The close similarity of the distributions of [3H]MDL100,907-labelled receptors and 5-HT2A mRNA further supports the selectivity of this radioligand for 5-HT2A receptors and suggests a predominant somatodendritic localization of these receptors. The present results point to [3H]MDL100,907 as the ligand of choice for the autoradiographic visualization of 5-HT2A receptors. 相似文献
983.
984.
The Impact of Driving Force on Electron Transfer Rates in Photovoltaic Donor–Acceptor Blends 下载免费PDF全文
985.
A new bootstrap test is introduced that allows for assessing the significance of the differences between stochastic algorithms in a cross-validation with repeated folds experimental setup. Intervals are used for modeling the variability of the data that can be attributed to the repetition of learning and testing stages over the same folds in cross validation. Numerical experiments are provided that support the following three claims: (1) Bootstrap tests can be more powerful than ANOVA or Friedman test for comparing multiple classifiers. (2) In the presence of outliers, interval-valued bootstrap tests achieve a better discrimination between stochastic algorithms than nonparametric tests. (3) Choosing ANOVA, Friedman or Bootstrap can produce different conclusions in experiments involving actual data from machine learning tasks. 相似文献
986.
987.
Rafael Jimenez Alcibiades Serrano Claudio Olalla 《International Journal of Rock Mechanics and Mining Sciences》2008,45(7):1153-1163
We present a novel methodology for estimation of equivalent Mohr–Coulomb strength parameters that can be used for design of supported tunnels in elasto-plastic rock masses satisfying the non-linear empirical Hoek–Brown failure criterion. We work with a general adimensional formulation of the Hoek–Brown failure criterion in the space of normalized Lambe's variables for plane stress, and we perform linearization considering the stress field in the plastic region around the tunnel. The procedure is validated using analytical solutions to a series of benchmark test cases. Numerical solutions are also employed to validate the procedure in cases for which analytical solutions are not available. Results indicate that the stress field in the plastic region around the tunnel, as well as the linearization method employed and the quality of the rock mass, has a significant impact on computed estimates of equivalent Mohr–Coulomb strength parameters. Results of numerical analyses also show that our proposed linearization method can be employed to estimate loads and moments on the tunnel support system. We recommend the equating model responses (EMR) method to compute equivalent Mohr–Coulomb strength parameters when the tunnel support pressure is accurately known, and we further show that our newly introduced linearization method can be employed as an alternative to the best fitting in the existing stress range (BFe) and best fitting in an artificial stress range (BFa) methods, providing performance estimates that are generally better than estimates of the BFe and BFa methods when differences with the response of the Hoek–Brown rock mass are of engineering significance (say more than 10%). 相似文献
988.
The literature on inequality among economies has focused mainly on analysing the dispersion of indicators such as current income per capita. In this paper we adopt a different approach from the usual one. In order to analyse inequality and convergence among Spanish regions, we propose to use a measure of permanent income that takes into account the entire life cycle dimension. On the basis of this approach, we make various simulations to determine the influence on inequality and convergence in permanent income of variables, such as survival rates and the existence or non-existence of convergence in current income. The results indicate that inequality in permanent income is clearly lower than that observed when the full life cycle of individuals is not taken into account. 相似文献
989.
Extraction of egg-yolk lecithin 总被引:5,自引:0,他引:5
Luz?E.?Palacios Tong?WangEmail author 《Journal of the American Oil Chemists' Society》2005,82(8):565-569
In this research, the extraction of egg-yolk lecithin with ethanol was studied. Extraction was performed with deoiled and
undeoiled yolks and with heated and unheated yolks. The yield of the extracted fraction relative to the initial material,
phospholipid (PL) purity, and cholesterol content of both the PC-enriched fractions and the remaining PL fractions were determined.
The yield and PL purity of the PC-enriched fractions obtained from the undeoiled yolks were 23.9 and 35.7%, and those obtained
from deoiled yolks were 13.5 and 53.3%. The recovery of total PL in the two fractions was higher from the undeoiled (70%)
than from the deoiled yolks (60%). However, heating had a negligible effect on PL extraction. Better enrichment of PC was
observed by extraction from the undeoiled than from the deoiled yolks. The cholesterol content of the PC-enriched fraction
obtained from the undeoiled yolks was much higher than that from the deoiled yolks. 相似文献
990.
Response of Epilachna paenulata to Two Flavonoids, Pinocembrin and Quercetin, in a Comparative Study
Georgina N. Diaz Napal Maria T. Defagó Graciela R. Valladares Sara M. Palacios 《Journal of chemical ecology》2010,36(8):898-904
We examined the effects of the flavonoids pinocembrin and quercetin on the feeding behavior, survival, and development of the Cucurbitaceae pest Epilachna paenulata (Coleoptera: Coccinellidae). In no-choice experiments, 48 hr-consumption of Cucurbita maxima Duch. leaves treated with pinocembrin at 1, 5, and 50 μg/cm2 was less than one third of that for leaves treated with 0.1 μg/cm2 of pinocembrin or untreated leaves. Larvae stopped feeding after 9 days of high doses of pinocembrin (5 and 50 μg/cm2), and larval weight and survival were negatively affected by pinocembrin at 1–50 μg/cm2. Delayed mortality in comparison to food-deprived larvae suggests that the mechanism of action for pinocembrin is chronic intoxication, rather than simple starvation from antifeedant effects. In contrast, leaf consumption and larval weight were not significantly affected by quercetin (at 0.1, 1, 5, and 50 μg/cm2) while mortality rates were only slightly increased. The response of E. paenulata larvae in a choice-test to combinations of pinocembrin at antifeedant doses (5 and 50 μg/cm2) and quercetin at phagostimulant doses (0.01 and 0.1 μg/cm2) indicated that the feeding deterrent activity of the former completely overshadowed the stimulant activity of the latter. These results demonstrate the different responses of one insect species to two widely distributed plant flavonoids. Pinocembrin strongly affected survival of E. paenulata while quercetin had only a weak effect without major consequences on the insect life-cycle. 相似文献