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101.
Summary During methotrexate-induced differentiation of cultured human choriocarcinoma (BeWo) cells, proliferation is inhibited, morphologic
and biochemical changes occur, and giant, often multinucleated, cells form. We have used the increase in cell volume as a
marker of the mature syncytiotrophoblastlike phenotype. Uninduced and differentiated BeWo cells are not spherical, and theoretical
considerations suggested that deviations in shape could result in significant errors in Coulter volume. To determine if the
values obtained by electrical pulse sizing reflected the actual mass of BeWo cells, we have evaluated the relationship between
Coulter volumes and intracellular water volumes obtained using a shape-independent estimate for eight cell types. A close
correlation (r
2=0.97) was found, indicating that cell volume changes in populations of irregularly shaped cells can be accurately measured
using a Coulter instrument.
Supported by an operating grant from the National Cancer Institute of Canada. N.S.B. was a recipient of a studentship award
from the Alberta Heritage Foundation for Medical Research. C.E.C. is a Senior Research Scientist of the National Cancer Institute
of Canada. The McEachern Laboratory is a research facility of the Faculty of Medicine, University of Alberta, and the Cross
Cancer Institute, Edmonton, Alberta. 相似文献
102.
103.
Ian C. West 《Journal of bioenergetics and biomembranes》1991,23(5):703-714
The term direct-coupled is considered in the context of redox-linked proton translocation mechanisms, and the origins of this concept, its philosophical implications, applications, and contributions to the development of bioenergetics, are discussed. 相似文献
104.
105.
Margaret Stebbing 《Journal of bioethical inquiry》2009,6(1):37-48
Debates about the regulatory requirements surrounding the introduction of nanotechnology products have, at least in Australia,
remained largely within disciplinary boundaries and industry and academic circles. This paper argues for a more interdisciplinary
and inclusive upstream debate about the introduction of ethical, regulatory and legal frameworks that may avoid the loss of
public trust that has characterised the introduction of many new technologies in the past. Insights from risk-perception theory
and research are used to introduce the notion of risk as narrative as a framework for action. This paper suggests three main strategies for moving forward; drawing insights from the “trust
gap” experiences of other new technologies; the application of the active form of the precautionary principle; and, the creation of nano-futures that meet both community and industry values through
effective public engagement. 相似文献
106.
107.
The lipid modified human N-Ras protein, implicated in human cancer development, is of particular interest due to its membrane anchor that determines the activity and subcellular location of the protein. Previous solid-state NMR investigations indicated that this membrane anchor is highly dynamic, which may be indicative of backbone conformational flexibility. This article aims to address if a dynamic exchange between three structural models exist that had been determined previously. We applied a combination of solid-state nuclear magnetic resonance (NMR) methods and replica exchange molecular dynamics (MD) simulations using a Ras peptide that represents the terminal seven amino acids of the human N-Ras protein. Analysis of correlations between the conformations of individual amino acids revealed that Cys 181 and Met 182 undergo collective conformational exchange. Two major structures constituting about 60% of all conformations could be identified. The two conformations found in the simulation are in rapid exchange, which gives rise to low backbone order parameters and nuclear spin relaxation as measured by experimental NMR methods. These parameters were also determined from two 300 ns conventional MD simulations, providing very good agreement with the experimental data. 相似文献
108.
当今,全球性的环境污染,生态破坏,人口爆炸,能源危机,资源枯竭,森林减少,水土流失,耕地退化,城市水荒,交通拥塞,住房紧张,城市病不断加剧……,归根结底都是人与自然失调造成的,正面临着人与自然是否协 相似文献
109.
生物竞争排斥对油藏微生物群落结构变化影响 总被引:1,自引:0,他引:1
【目的】海上S油田采用生物竞争排斥技术治理油藏硫化氢产出取得一定成效,本研究通过揭示该技术对油藏环境中微生物群落结构的影响,尝试研究硫化氢治理过程中产生效果差异的因素。【方法】采用高通量测序分析等方法对加入硝酸盐、亚硝酸盐等药剂后,治理效果低效井、高效井及未治理井中不同微生物群落结构变化进行分析。【结果】与低效井和未治理井相比,高效井中的反硝化菌和石油降解菌种类和丰度明显增加,其中石油降解菌增加24.14%,反硝化细菌增加5.23%;Fe2+、Zn2+等离子的存在对不同井间治理效果差异和微生物群落变化具有一定影响。【结论】海上油田硫化氢治理中,生物竞争排斥技术不仅可以明显降低硫化氢产出,同时对油藏微生物群落环境也影响显著,微生物群落结构分析可作为硫化氢治理效果评价的重要指标,为海上油田硫化氢治理工作提供技术支持。 相似文献
110.