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871.
Due to their toxicity, the increased distribution of microcystins (MCs) has become an important worldwide problem. MCs have
been recognized as inhibitors of protein phosphatase 2A (PP2A) through their binding to the PP2A catalytic subunit. However,
the exact mechanism of MC toxicity has not been elucidated, especially concerning the cellular response and its autoregulation.
To further dissect the role of PP2A in MC-induced toxicity, the present study was undertaken to determine the response of
PP2A in human amniotic epithelial (FL) cells treated with microcystin-LR (MCLR), one of the MC congeners. The results show
that a low-dose treatment of MCLR in FL cells for 6 h induced an increase in PP2A activity, and a high-dose treatment of MCLR
for 24 h decreased the activity of PP2A, as expected. The increased mRNA and protein levels of the PP2A C subunit may explain
the increased activity of PP2A. Furthermore, MCLR altered microtubule post-translational modifications through PP2A. These
results further clarify the underlying mechanism how MCLR affects PP2A and may be helpful for elucidating the complex toxicity
of MCLR. 相似文献
872.
Wang LR Zhang GB Chen J Li J Li MW Xu N Wang Y Shen Tu JZ 《Journal of Zhejiang University. Science. B》2011,12(3):174-179
Objective
To evaluate the predictive values of gene expressions of ribonucleotide reductase M1 (RRM1) and breast cancer susceptibility gene 1 (BRCA1) in peripheral blood from Chinese patients with non-small-cell lung cancer (NSCLC) treated with gemcitabine plus platinum. 相似文献873.
He XL Yin HL Wu J Zhang K Liu Y Yuan T Rao HL Li L Yang G Zhang XM 《Journal of Zhejiang University. Science. B》2011,12(1):32-39
Radiation therapy has been widely applied in cancer treatment. However, it often causes thrombocytopenia (deficiency of white
blood cells) as an adverse effect. Recombinant human interleukin-6 (rhIL-6) has been found to be a very effective way against
this thrombocytopenia, but IL-6 has low stability in blood, which reduces its efficacy. To increases the stability and half-life
of rhIL-6, it was modified by polyethylene glycol (PEG). The pharmacokinetics and the tissue distribution of PEG-rhIL-6 labeled
with 125I were examined after subcutaneous injection in rats. The pharmacokinetic pattern of PEG-rhIL-6 was defined with linear-kinetics,
and we fitted a one-compartment model with half-lives of 10.44–11.37 h (absorption, t
1/2K
a) and 19.77–21.53 h (elimination, t
1/2Ke), and peak concentrations at 20.51–21.96 h (t
peak) in rats. Half-lives and t
peak of PEG-rhIL-6 were longer than those of rhIL-6 previously reported. In the present study, for deposition of PEG-rhIL-6 in
rats, the tissue distribution examination showed that blood was the major organ involved, rather than liver. However, as to
the elimination of PEG-rhIL-6, the major organ was the kidney. The excretion fraction of the injection dose recovered from
urine was 23.32% at 192 h after subcutaneous administration. Less than 6% of PEG-rhIL-6 was eliminated via the feces at 192
h. These results indicate that PEG-rhIL-6 is a good candidate drug formulation for patients with cancer. 相似文献
874.
875.
877.
科学地评价分析试卷质量,对提高教学质量,使目前的教学测评工作逐步走上一个新台阶具有重要的现实意义。本文以我校营养与食品卫生学试题库中350道客观题为研究对象,对试卷成绩分布、试题难度、区分度和信度进行综合分析。发现了题库中试题难度较简单,区分度较为合适,试卷是可靠、有效的,能够客观、公正、科学地测试和评价学生。 相似文献
878.
为适应我国工业化发展进程,培养和造就一大批创新能力强、适应我国经济社会发展需要的土木工程技术人才,探讨了通过若干个相关模块的有机搭配,将传统的按学科知识体系构建专业课程体系,转变为按专业能力体系构建专业模块化体系,将传统的以学科为背景的课程教学改变为以培养专业能力为出发点的模块化教学。通过合理安排各模块的教学活动,完成人才培养的全过程。 相似文献
879.
We describe how a team approach that we developed as a mentoring strategy can be used to recruit, advance, and guide students to be more interested in the interdisciplinary field of mathematical biology, and lead to success in undergraduate research in this field. Students are introduced to research in their first semester via lab rotations. Their participation in the research of four faculty members-two from biology and two from mathematics-gives them a first-hand overview of research in quantitative biology and also some initial experience in research itself. However, one of the primary goals of the lab rotation experience is that of developing teams of students and faculty that combine mathematics and statistics with biology and the life sciences, teams that subsequently mentor undergraduate research in genuine interdisciplinary environments. Thus, the team concept serves not only as a means of establishing interdisciplinary research, but also as a means of incorporating new students into existing research efforts that will then track those students into meaningful research of their own. We report how the team concept is used to support undergraduate research in mathematical biology and what types of team-building strategies have worked for us. 相似文献
880.
为了研究不同压力下具有Marangoni效应的混合蒸气在可拆板式换热器中的凝结换热特性,设计并搭建了具有高气密性的板式换热器实验台。通过实验方法,在混合蒸气流速25 m/s的条件下,研究了不同气相酒精质量浓度(0%,1%,10%,50%)在不同蒸气压力(70,80,90 k Pa)下,饱和混合蒸气在可拆板式换热器中的凝结换热和蒸气侧压降随冷却水进口温度变化的特性。板式换热器由三块人字波纹板片组成,换热方式为逆流换热。实验结果表明,在相同蒸气浓度、蒸气流速和冷却水进口温度条件下,高压下的平均换热系数比低压大,而压降相反。蒸气压力对平均换热和压降的影响因混合蒸气酒精浓度的不同而不同,与纯水相比,在低浓度(1%)时,压降几乎相同,而传热系数增大约6%;在中浓度(10%)和高浓度(50%)时,压降明显增大,同时传热系数也有显著降低。 相似文献