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   27篇
  免费   0篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   2篇
  2013年   4篇
  2012年   1篇
  2011年   1篇
  2010年   1篇
  2009年   2篇
  2007年   1篇
排序方式: 共有27条查询结果,搜索用时 15 毫秒
21.
Breast cancer is the most prevalent cancer and the main cause of cancer-related death in women worldwide. There are limitations associated with the existing clinical tools for breast cancer detection and alternative modalities for early detection and classification of breast cancer are urgently needed. Here we describe an optical imaging technique, called multispectral diffuse optical tomography (DOT), and demonstrate its ability of non-invasively evaluating nuclear morphometry for differentiating benign from malignant lesions. Photon densities along the surface of the breast were measured to allow for the extraction of three statistical parameters including the size, elongation and density of nuclei inside the breast tissue. The results from 14 patients (4 malignant and 10 benign lesions) show that there exist significant contrasts between the diseased and surrounding normal nuclei and that the recovered nuclear morphological parameters agree well the pathological findings. We found that the nuclei of cancer cells were less-spherical compared with those of surrounding normal cells, while the nuclear density or volume fraction provided the highest contrast among the three statistical parameters recovered. This pilot study demonstrates the potential of multispectral DOT as a cellular imaging method for accurate determination of breast cancer.  相似文献   
22.
Aims Effects of insulin and ascorbic acid on expression of Bcl-2 family proteins and caspase-3 activity in hippocampus of diabetic rats were evaluated in this study. Methods Diabetes was induced in Wistar male rats by streptozotocin (STZ). Six weeks after verification of diabetes, the animals were treated for 2 weeks with insulin or/and ascorbic acid in separate groups. Hippocampi of rats were removed and evaluation of Bcl-2, Bcl-xL, and Bax proteins expression in frozen hippocampi tissues were done by SDS-PAGE electrophoresis and blotting. The Bcl-2, Bcl-xL, and Bax proteins bands were visualized after incubation with specific antibodies using enhanced chemiluminescences method. Caspase-3 activity was determined using the caspase-3/CPP32 Fluorometric Assay Kit. Results Diabetic rats showed increase in Bax protein expression and decrease in Bcl-2 and Bcl-xL proteins expression. The Bax/Bcl-2 and Bax/Bcl-xL ratios were found higher compared with non-diabetic control group. Treatments with insulin and/or ascorbic acid were resulted in decrease in Bax protein expression and increase in Bcl-2 and Bcl-xL proteins expression. The Bcl-2/Bax and Bcl-xL/Bax ratios were found higher in treated groups than untreated diabetic group. Caspase-3 activity level was found higher in diabetic group compared with non-diabetic group. Treatment with insulin and ascorbic acid did downregulated caspase-3 activity. Conclusions Our data provide supportive evidence to demonstrate the antiapoptotic effects of insulin and ascorbic acid on hippocampus of STZ-induced diabetic rats.  相似文献   
23.
Effect of paclobutrazol (PBZ) treatment on salinity tolerance of wheat (Triticum aestivum) was investigated on a salt-tolerant (Karchia-65) and salt-sensitive (Ghods) cultivars. Salinity significantly reduced the investigated growth parameters such as plant height, length and area of sixth leaf, root length, fresh and dry weight of shoot, roots and sixth leaf, water content (WC) of plant and seeds weight in the both cultivars. The negative effect of salinity in Ghods cultivar was more than Karchia cultivar. However, PBZ treatment reduced the growth in both cultivars, the differences in plant growth among various levels of NaCl decreased in PBZ-treated plants. Salt stress resulted in high accumulation of Na+ in the sixth leaf and roots in both cultivars, particularly in Ghods cultivar. Against Karchia cultivar, salt stress decreased the storage of K+, P and N in sixth leaf and roots in Ghods cultivar. In the both cultivars, PBZ treatment enhanced the K+, P and N contents in sixth leaf and roots by increasing salinity. Although PBZ treatment decreased the growth of plants, it improved the weight of seeds against stress damage. PBZ treatment reduced the accumulation of harmful Na+ ion in plant tissues while increased the K+, P and N contents. These observations suggest that PBZ treatment may increase tolerance by diminishing ionic imbalance caused by salt stress.  相似文献   
24.
Based on light and scanning electron microscopical studies, a new nematode parasite, Barracudia australiensis n. sp. (Philometridae), is described from the gall-bladder of the marine fish (obtuse barracuda) Sphyraena obtusata Cuvier (Sphyraenidae, Perciformes) from off the eastern Pacific coast of Australia, for which a new genus Barracudia n. g. is established. This new genus is mainly characterised by features found in the male: sickle-shaped, ventrally curved spicules, a gubernacum with a broad, dorsally bent distal portion and a markedly dorsoventrally elongated cloacal aperture. Based on these features, Barracudia spp. conspicuously differ from representatives of all other philometrid genera with known males. Philometra philippinensis Quiazon & Yoshinaga, 2013 is transferred to Barracudia as B. philippinensis (Quiazon & Yoshinaga, 2013) n. comb. Barracudia australiensis is the third nominal species of philometrids described from the Sphyraenidae and the 19th species of the Philometridae recorded from fishes in Australian waters.  相似文献   
25.
Two of the Coronavirus Disease 2019 (COVID-19) vaccines currently approved in the United States require 2 doses, administered 3 to 4 weeks apart. Constraints in vaccine supply and distribution capacity, together with a deadly wave of COVID-19 from November 2020 to January 2021 and the emergence of highly contagious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants, sparked a policy debate on whether to vaccinate more individuals with the first dose of available vaccines and delay the second dose or to continue with the recommended 2-dose series as tested in clinical trials. We developed an agent-based model of COVID-19 transmission to compare the impact of these 2 vaccination strategies, while varying the temporal waning of vaccine efficacy following the first dose and the level of preexisting immunity in the population. Our results show that for Moderna vaccines, a delay of at least 9 weeks could maximize vaccination program effectiveness and avert at least an additional 17.3 (95% credible interval [CrI]: 7.8–29.7) infections, 0.69 (95% CrI: 0.52–0.97) hospitalizations, and 0.34 (95% CrI: 0.25–0.44) deaths per 10,000 population compared to the recommended 4-week interval between the 2 doses. Pfizer-BioNTech vaccines also averted an additional 0.60 (95% CrI: 0.37–0.89) hospitalizations and 0.32 (95% CrI: 0.23–0.45) deaths per 10,000 population in a 9-week delayed second dose (DSD) strategy compared to the 3-week recommended schedule between doses. However, there was no clear advantage of delaying the second dose with Pfizer-BioNTech vaccines in reducing infections, unless the efficacy of the first dose did not wane over time. Our findings underscore the importance of quantifying the characteristics and durability of vaccine-induced protection after the first dose in order to determine the optimal time interval between the 2 doses.

There are two widely used COVID-19 vaccination strategies; administering the two doses three to four weeks apart or delaying the administration of the second dose. A modelling study calibrated to COVID-19 spread and vaccination in the US shows that delaying the second dose can maximize the benefits of vaccination programs under certain conditions.  相似文献   
26.
So far, no detailed view has been expressed regarding the interactions between vancomycin and racemic compounds including mandelic acid. In the current study, a chiral stationary phase was prepared by using 3-aminopropyltriethoxysilane and succinic anhydride to graft carboxylated silica microspheres and subsequently by activating the carboxylic acid group for vancomycin immobilization. Characterization by elemental analysis, Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance, and thermogravimetric analysis demonstrated effective functionalization of the silica surface. R and S enantiomers of mandelic acid were separated by the synthetic vancomycin column. Finally, the interaction between vancomycin and R/S mandelic acid enantiomers was simulated by Auto-dock Vina. The binding energies of interactions between R and S enantiomers and vancomycin chiral stationary phase were different. In the most probable interaction, the difference in mandelic acid binding energy was approximately 0.2 kcal/mol. In addition, circular dichroism spectra of vancomycin interacting with R and S enantiomers showed different patterns. Therefore, R and S mandelic acid enantiomers may occupy various binding pockets and interact with different vancomycin functions. These observations emphasized the different retention of R and S mandelic acid enantiomers in vancomycin chiral column.  相似文献   
27.
Journal of Plant Growth Regulation - Water scarcity is one of the main factors limiting crop production worldwide. The study on response of saffron to irrigation regime showed that one-time...  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