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排序方式: 共有279条查询结果,搜索用时 15 毫秒
51.
Biron PA Massarin S Alonzo F Garcia-Sanchez L Charles S Billoir E 《Environmental science & technology》2012,46(2):1136-1143
As part of the ecological risk assessment associated with radionuclides in freshwater ecosystems, toxicity of waterborne uranium was recently investigated in the microcrustacean Daphnia magna over a three-generation exposure (F0, F1, and F2). Toxic effects on daphnid life history and physiology, increasing over generations, were demonstrated at the organism level under controlled laboratory conditions. These effects were modeled using an approach based on the dynamic energy budget (DEB). For each of the three successive generations, DEBtox (dynamic energy budget applied to toxicity data) models were fitted to experimental data. Lethal and sublethal DEBtox outcomes and their uncertainty were projected to the population level using population matrix techniques. To do so, we compared two modeling approaches in which experimental results from F0, F1, and F2 generations were either considered separately (F0-, F1-, and F2-based simulations) or together in the actual succession of F0, F1, and F2 generations (multi-F-based simulation). The first approach showed that considering results from F0 only (equivalent to a standard toxicity test) would lead to a severe underestimation of uranium toxicity at the population level. Results from the second approach showed that combining effects in successive generations cannot generally be simplified to the worst case among F0-, F1-, and F2-based population dynamics. 相似文献
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Thermoneutrality results in prominent diet‐induced body weight differences in C57BL/6J mice,not paralleled by diet‐induced metabolic differences
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54.
Petrocelli John V.; Percy Elise J.; Sherman Steven J.; Tormala Zakary L. 《Canadian Metallurgical Quarterly》2011,100(1):30
Counterfactual thoughts typically take the form of implied or explicit if–then statements. We propose that the multiplicative combination of “if likelihood” (the degree to which the antecedent condition of the counterfactual is perceived to be likely) and “then likelihood” (the perceived conditional likelihood of the outcome of the counterfactual, given the antecedent condition) determine the strength and impact of counterfactuals. This construct, termed counterfactual potency, is a reliable predictor of the degree of influence of counterfactual thinking upon judgments of regret, causation, and responsibility. Through 4 studies, we demonstrate the predictive power of this construct in a variety of contexts and show that it plays a causal role in determining the strength of the effects of counterfactual thought. Implications of counterfactual potency as a central factor of counterfactual influence are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
55.
Gao Y Talgorn E Aerts M Trinh MT Schins JM Houtepen AJ Siebbeles LD 《Nano letters》2011,11(12):5471-5476
PbSe quantum-dot solids are of great interest for low cost and efficient photodetectors and solar cells. We have prepared PbSe quantum-dot solids with high charge carrier mobilities using layer-by-layer dip-coating with 1,2-ethanediamine as substitute capping ligands. Here we present a time and energy resolved transient absorption spectroscopy study on the kinetics of photogenerated charge carriers, focusing on 0-5 ps after photoexcitation. We compare the observed carrier kinetics to those for quantum dots in dispersion and show that the intraband carrier cooling is significantly faster in quantum-dot solids. In addition we find that carriers diffuse from higher to lower energy sites in the quantum-dot solid within several picoseconds. 相似文献
56.
Wilson PR Roschuk T Dunn K Normand EN Chelomentsev E Zalloum OH Wojcik J Mascher P 《Nanoscale research letters》2011,6(1):168
Silicon nanoclusters (Si-ncs) embedded in silicon nitride films have been studied to determine the effects that deposition
and processing parameters have on their growth, luminescent properties, and electronic structure. Luminescence was observed
from Si-ncs formed in silicon-rich silicon nitride films with a broad range of compositions and grown using three different
types of chemical vapour deposition systems. Photoluminescence (PL) experiments revealed broad, tunable emissions with peaks
ranging from the near-infrared across the full visible spectrum. The emission energy was highly dependent on the film composition
and changed only slightly with annealing temperature and time, which primarily affected the emission intensity. The PL spectra
from films annealed for duration of times ranging from 2 s to 2 h at 600 and 800°C indicated a fast initial formation and
growth of nanoclusters in the first few seconds of annealing followed by a slow, but steady growth as annealing time was further
increased. X-ray absorption near edge structure at the Si K- and L3,2-edges exhibited composition-dependent phase separation and structural re-ordering of the Si-ncs and silicon nitride host
matrix under different post-deposition annealing conditions and generally supported the trends observed in the PL spectra. 相似文献
57.
Sakthi Lenin Elise Ponthier Kaitlin G. Scheer Erica C. F. Yeo Melinda N. Tea Lisa M. Ebert Mariana Oksdath Mansilla Santosh Poonnoose Ulrich Baumgartner Bryan W. Day Rebecca J. Ormsby Stuart M. Pitson Guillermo A. Gomez 《International journal of molecular sciences》2021,22(9)
Glioblastoma is one of the most common and lethal types of primary brain tumor. Despite aggressive treatment with chemotherapy and radiotherapy, tumor recurrence within 6–9 months is common. To overcome this, more effective therapies targeting cancer cell stemness, invasion, metabolism, cell death resistance and the interactions of tumor cells with their surrounding microenvironment are required. In this study, we performed a systematic review of the molecular mechanisms that drive glioblastoma progression, which led to the identification of 65 drugs/inhibitors that we screened for their efficacy to kill patient-derived glioma stem cells in two dimensional (2D) cultures and patient-derived three dimensional (3D) glioblastoma explant organoids (GBOs). From the screening, we found a group of drugs that presented different selectivity on different patient-derived in vitro models. Moreover, we found that Costunolide, a TERT inhibitor, was effective in reducing the cell viability in vitro of both primary tumor models as well as tumor models pre-treated with chemotherapy and radiotherapy. These results present a novel workflow for screening a relatively large groups of drugs, whose results could lead to the identification of more personalized and effective treatment for recurrent glioblastoma. 相似文献
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The authors have reviewed 37 patients aged 64 to 91 years or their charts in the purpose to evaluate the results of surgical treatment of severe acquired contractures of arms hands and legs. They describe the deformations, surgical technique, morbidity, and the results. 4 patients deceased within the first week after surgery; morbidity was very low. The results were satisfactory: nursing was greatly facilitated and pain during nursing care and toilet disappeared, the patients could again seat in a wheel chair. They conclude that this surgery can be very helpful for these disabled patients. 相似文献
60.
Lerman Caryn; Caporaso Neil; Main David; Audrain Janet; Boyd Neal R.; Bowman Elise D.; Shields Peter G. 《Canadian Metallurgical Quarterly》1998,17(1):56
This study evaluated whether there are genetic subgroups of depressed individuals who are more or less predisposed to engage in self-medication smoking practices. Smokers (N?=?231) completed self-report questionnaires of depression and smoking practices and were genotyped for the dopamine D4 (DRD4) gene. A significant interaction (DRD4 Genotype?×?Depression) was found for stimulation smoking and negative-affect reduction smoking. Specifically, these smoking practices were significantly heightened in depressed smokers homozygous for the short alleles of DRD4 but not in those heterozygous or homozygous for the long alleles of DRD4. These preliminary results suggest that the rewarding effects of smoking and the beneficial effects of nicotine replacement therapy for depressed smokers may depend, in part, on genetic factors involved in dopamine transmission. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献