首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   46篇
  免费   10篇
  56篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   5篇
  2017年   3篇
  2016年   6篇
  2015年   3篇
  2014年   4篇
  2013年   7篇
  2012年   1篇
  2011年   2篇
  2010年   1篇
  2009年   2篇
  2008年   1篇
  2007年   4篇
  2006年   3篇
  2005年   2篇
  2004年   5篇
  2003年   1篇
  2002年   1篇
  2000年   1篇
排序方式: 共有56条查询结果,搜索用时 15 毫秒
21.
Components of the cellular translation machinery are targets of caspase-mediated cleavage during apoptosis that correlates with the inhibition of protein synthesis, which accompanies apoptosis. Paradoxically, protein synthesis is required for apoptosis to occur in many experimental settings. Previous studies showed that two proteins that regulate apoptosis by controlling caspase activity, XIAP and Apaf-1, are translated by a unique, cap-independent mechanism mediated by an internal ribosome entry site (IRES) that is used preferentially under conditions in which normal cap-dependent translation is repressed. We investigated the regulation of XIAP and Apaf-1 following UVC irradiation. We show that UVC irradiation leads to the inhibition of translation and cell death. Furthermore, IRES-mediated translation of Apaf-1, but not XIAP, is enhanced by UVC irradiation, and this increase in Apaf-1 translation correlated with cell death. The enhanced Apaf-1 IRES-mediated translation is caspase-independent but is negatively modulated by the eIF2alpha kinase protein kinase RNA-like endoplasmic reticulum kinase. These data suggest that progression of UV-induced apoptosis requires IRES-mediated translation of Apaf-1 to ensure continuous levels of Apaf-1 despite an overall suppression of protein synthesis.  相似文献   
22.
23.
Camelina oil-cakes results after the extraction of oil from Camelina sativa plant. In this study, camelina oil-cakes were fed to fattening pigs for 33 days and its effect on performance, plasma biochemical analytes, pro-/anti-inflammatory mediators and antioxidant detoxifying defence in spleen was investigated in comparison with sunflower meal. 24 crossbred TOPIG pigs were randomly assigned to one of two experimental dietary treatments containing either 12% sunflower meal (treatment 1-T1), or 12.0% camelina oil-cakes, rich in polyunsaturated fatty acids ω-3 (ω-3 PUFA) (treatment 2-T2). The results showed no effect of T2 diet (camelina cakes) on feed intake, average weight gain or feed efficiency. Consumption of camelina diet resulted in a significant decrease in plasma glucose concentration (18.47%) with a trend towards also a decrease of plasma cholesterol. In spleen, T2 diet modulated cellular immune response by decreasing the protein and gene expression of pro-inflammatory markers, interleukin 1-beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin (IL-8) and cyclooxigenase 2 (COX-2) in comparison with T1 diet. By contrast, T2 diet increased (P<0.05) in spleen the mRNA expression of antioxidant enzymes, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase 1 (GPx1) by 3.43, 2.47 and 1.83 fold change respectively, inducible nitric oxide synthase (iNOS) (4.60 fold), endothelial nitric oxide synthase (eNOS) (3.23 fold) and the total antioxidant level (9.02%) in plasma. Camelina diet increased also peroxisome-proliferator activated receptor gamma (PPAR-γ) mRNA and decreased that of mitogen-activated protein kinase 14 (p38α MAPK) and nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB). At this level of inclusion (12%) camelina oil-cakes appears to be a potentially alternative feed source for pig which preserves a high content of ω-3 PUFA indicating antioxidant properties by the stimulation of detoxifying enzymes expression and the suppression of spleen pro-inflammatory markers.  相似文献   
24.

Purpose

In this study, life cycle assessment (LCA) is applied to a sample of 40 low-energy individual houses for the French context in order to identify guidance values for different environmental priorities (energy and water consumption, greenhouse gases emissions, waste generation etc.).

Methods

Calculation rules for the LCA derived from EeBGuide guidance and HQE Performance specific rules for the French context. Data are based on Environmental Product Declaration (EPD for the impacts related to products and technical equipment while generic data are used for energy and water processes. The LCA is defined for the entire life cycle of a building from cradle-to-grave according to NF EN 15978 standard. It includes the products and equipment implemented in the building, the different uses of energy for heating, domestic hot water, lighting, ventilation and auxiliaries, and the different uses of water consumption.

Results and discussion

Results for the 40 houses showed that the average life cycle non-renewable primary energy consumption is about 37 kWh/(m2*year) while the life cycle greenhouse gases emissions are of 8.4 kg CO2-eq/(m2*year). The embodied impacts represent between 40% and 72% for the following indicators: acidification, global warming, non-renewable primary energy, and radioactive waste. The net fresh water use is mostly determined by the direct use of the water in use, and the non-hazardous waste indicator is only linked to the materials and equipment. When integrating the variability of the different houses design, energy performance, climate requirements, it was found that those values can vary of an order of two between the 10 and 90% percentiles’ values. It was found that the results are also sensitive to the enlargement of the system boundaries (e.g. inclusion of the other uses of energy such as building appliances) and the modification of the reference study period.

Conclusions and recommendations

This study provided a first set of LCA guidance values describing a range of environmental impacts for new low-energy individual houses in France. Results were also reported for different design parameters, system boundaries and reference study period. The outcomes of this study can now serve as a basis to guide and support new LCA-based labelling systems developed by public authorities and labelling schemes (e.g. the HQE Association).
  相似文献   
25.
Biologically active Knoevenagel condensates (114) of diarylheptanoids: 1,7-bis(3-methoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione and 1,7-bis(3-ethoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione, were synthesized and structurally characterized. Compounds 114 exhibited cytotoxicity against colon carcinoma cells, and their antiproliferative effect was associated with a significant decrease of multidrug resistance proteins. One of the underlying mechanisms of these effects is the reduction of intracellular and extracellular SOD enzymes by compounds 1, 12 and 14, which render the tumor cells more vulnerable to oxidative stress.  相似文献   
26.
27.
Regulated protein degradation is essential for eukaryotic cell cycle progression. The anaphase-promoting complex/cyclosome (APC/C) is responsible for the protein destruction required for the initiation of anaphase and the exit from mitosis, including the degradation of securin and B-type cyclins. We initiated a study of the APC/C in the multinucleated, filamentous ascomycete Ashbya gossypii to understand the mechanisms underlying the asynchronous mitosis observed in these cells. These experiments were motivated by previous work which demonstrated that the mitotic cyclin AgClb1/2p persists through anaphase, suggesting that the APC/C may not be required for the division cycle in A. gossypii. We have now found that the predicted APC/C components AgCdc23p and AgDoc1p and the targeting factors AgCdc20p and AgCdh1p are essential for growth and nuclear division. Mutants lacking any of these factors arrest as germlings with nuclei blocked in mitosis. A likely substrate of the APC/C is the securin homologue AgPds1p, which is present in all nuclei in hyphae except those in anaphase. The destruction box sequence of AgPds1p is required for this timed disappearance. To investigate how the APC/C may function to degrade AgPds1p in only the subset of anaphase nuclei, we localized components and targeting subunits of the APC/C. Remarkably, AgCdc23p, AgDoc1p, and AgCdc16p were found in all nuclei in all cell cycle stages, as were the APC/C targeting factors AgCdc20p and AgCdh1p. These data suggest that the AgAPC/C may be constitutively active across the cell cycle and that proteolysis in these multinucleated cells may be regulated at the level of substrates rather than by the APC/C itself.  相似文献   
28.
Modulating the microbiota of the gastrointestinal tract through probiotics is an alternative to the conventional treatment of various diseases, based on synthetic drugs. The lifestyle, nutrition and stress of the present modern society could be among the factors responsible for modifications in the intestinal microbiota, correlated with specific diseases. The present study describes the positive effects of probiotics use, with special reference to the yeasts use in several frequently encountered diseases, such as hypercholesterolemia, the irritable bowel syndrome, gastritis and several uro-genital disorders.  相似文献   
29.

Purpose

The objective of the paper is to discuss the role of a new guidance document for life cycle assessment (LCA) in the construction sector available as an online InfoHub.

Methods

This InfoHub derives from the EeBGuide European project that aimed at developing a guidance document for energy-efficient building LCA studies. The InfoHub is built on reference documents such as the ISO 14040-44 standards, the EN 15804 and EN 15978 standards as well as the ILCD Handbook. The guidance document was filled with expertise and knowledge of several experts. The focus was put on providing scientifically sound, yet practical guidance.

Results

The EeBGuide InfoHub is an online guidance document, setting rules for conducting LCA studies and giving instructions on how to do this. The document has a section on buildings—new and existing—and a section on construction products. It is structured according to the life cycle stages of the European standards EN 15804 and EN 15978, covering all aspects of LCA studies by applying provisions from these standards and the ILCD handbook, wherever applicable. The guidance is presented for different scopes of studies by means of three study types. For the same system boundaries, default values are proposed in early or quick assessment (screening and simplified LCA) while detailed calculation rules correspond to a complete LCA. Such approach is intended to better match the user needs in the building sector.

Conclusions and recommendations

This paper can be viewed as a contribution to the ongoing efforts to improve the consistency and harmonisation in LCA studies for building products and buildings. Further contributions are now needed to improve building LCA guidance and to strengthen links between research, standardisation and implementation of LCA in the construction practice.  相似文献   
30.
The coffee oil has a promising potential to be used in food industry, but an efficient use, especially in products that required high-temperature heating, depends on its chemical composition and the changes induced by processing. Since there is little information on this topic, the aim of our study was to investigate the crude green and roasted coffee oil (GCO, RCO) and heated (HGCO, HRCO) for 1 h at 200°C, by Fourier Transform Infrared (FTIR) spectroscopy and in terms of antioxidant and antimicrobial properties. The results of FTIR spectroscopy revealed that no statistically significant differences (one-way ANOVA, p>0.05) in the oxidative status of GCO and RCO were found. The coffee oils heating induced significant spectral changes in the regions 3100–3600 cm–1, 2800–3050 cm–1 and 1680–1780 cm–1 proved by the differences in the absorbance ratios A 3009 cm−1/A 2922 cm−1, A 3009 cm−1/A 2853 cm−1, A 3009 cm−1/A 1744 cm−1, A 1744 cm−1/A 2922 cm−1. These alterations were related to the reduction of the unsaturation degree due to primary and secondary oxidation processes of the lipid fraction. The radical scavenging ability of oils investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay revealed that the IC50 value of GCO was significantly lower than of RCO (p<0.05). The IC50 values of crude coffee oils were lower than those of heated samples. The antioxidant activity of oils was attributed to both antioxidant compounds with free-radical scavenging capacity and to lipids oxidation products generated by heating. In the first 6 h of incubation, the inhibitory activity of crude oils against E. coli and E. faecalis was not significantly different to the control (p>0.05). Also, HGCO and HRCO showed significantly different inhibitory potential related to the control (p<0.05). The heating induced statistically significant decreases in the effectiveness of coffee oils against the tested bacteria. GCO proved to be the most effective among investigated coffee oils against the tested bacteria.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号