An experimentally supported, mathematical explanation of the gas chromatographic elution behaviour of the long-chain carbon members of the homologous series

By substituting the saturated vapour phase tension of the pure normal hydrocarbons described by the Clausius-Clapeyron law into the accepted expression of the specific retention volume (V_g,T), a theoretically coherent and relatively simple mathematical evidence of the elution behaviour of the homologous members has been deduced. It gives exponential retention time dependence on carbon number for isothermal, and nearly equidistant (i.e., approximately linear retention-time dependence on carbon number) elution for linear temperature programmed gas chromatographic runs. The final equations are in close correlation with the experimental results. Special emphasis is placed on the fact that a good approximation—not strict physical laws—have been found.     

糖尿病患者反复住院的相关因素探讨

目的 探讨糖尿病患者反复住院的相关因素，减少糖尿病患者住院次数。方法 采用自制问卷对反复住院的30例患者作相关因素调查。结果 糖尿病患者反复住院的相关因素有：（1）对疾病认识不清（21人次，占40．38％）。（2）对疾病不够重视（15人次，占28．84％）。（3）对医护不满意（2人次，占3．85％）。（4）社会，经济及其他因素（14人次，占26．93％）。结论 健康教育是今后糖尿病预防和治疗的重点。     

中国汉译西医学著作在日本的流传和影响

调查了十九世纪汉译西洋医学著作在日本的出版和流传情况，有９种汉译西洋医学著作曾在日本出版，其中６种曾多次再版，７种有和训或和译本，这些著作曾在日本医生中广泛流传，促进了西洋医学在日本的传播和普及，对日本医学从传统医学向现代医学的转变起过一定的作用。本文还分析了汉译西洋医学著作能够在日本广泛流传的原因     

现代观念与电视剧创作

转型期的文学艺术总体格局出现了引人注目的变化 ,电视剧已成为百姓日常文化消费的主要对象 ;在艺术风格上呈现世俗化、平民化趋向的电视剧创作 ,同样要“代表先进文化的前进方向” ,这就要求创作者更新并优化观念。现代观念的涵义是丰富的 ,与时俱进的 ;一些电视剧的缺失都可以从中找到原因。而近几年涌现的一批在大众化、精品化方面取得重大进展的多种题材的电视剧 ,关键在于观念的突破带动了思想和艺术的创新     

Peripheral nerve stimulation during MRI: Effects of high gradient amplitudes and switching rates

The application of high gradient amplitudes and switching rates for MRI and spectroscopy, resulting in short rise times for the gradient field and high changes of the magnetic flux density in the patient, is known to possibly evoke peripheral nerve stimulation (PNS) in patients. These effects have been studied on 20 volunteers under different experimental circumstances. The results of these measurements are partially in line with earlier findings reported in the literature. New information is found for the dependence of the PNS threshold level as a function of the rise time of the gradient waveform. The PNS threshold level, expressed in terms of dB/dt, is found to be proportional with t^?05, where t is the switch time for the gradients. Indications are found that |B|, the modulus of the gradient vector field, is more closely related to the PNS threshold level than B_z, the imaging component of the gradient field. From the experiments, it is furthermore concluded that only for the imaging protocols characterized by the application of long bipolar repetitive gradient pulse trains, such as echo-planar imaging, PNS is expected at the reported threshold levels. For the protocols based on spin echo, turbo spin echo, inversion recovery, fast field echo, etc., characterized by shorter gradient pulse trains, the threshold levels are expected to be much higher.     

电子时代的医学图书馆馆员和循证医学

简要阐述了循证医学的概念及其基本特点,探讨了电子时代循证医学对于医学图书馆员的要求,同时提出了电子时代医学图书馆员应该具备的知识和技能.     

K562／ADM耐药细胞株的建立及其生物学特性的初步观察

我们建立的K562/ADM耐药细胞株,在ADM浓度为2.4μg/m1(4.46μM)中已稳定培养3.5个月,传了30—35代,K562/ADM亦具有多药耐受件(Multidrug Resistance,MDR)的特点,对ADM、VCR、AT—1258和DDP的耐受性分别为K562的114.7、94.0、13.3和7.4倍,但对5—FU不产生交叉耐药。K562和K562/ADM的倍增时间分别为19.2h和52.8h,集落生成率分别为37.5％和11.1％,K562染色体数为34—68,中位数为56;K562/MDM染色体数为32—90,中位数为50,K562/ADM可做为耐药机理和克服耐药措施研究的极好模型。     

Reversible and irreversible effects of chemical fixation on the NMR properties of single cells.

The effects of chemical fixation are known to alter MR parameters, such as relaxation times and the apparent diffusion coefficient (ADC) of water. It is often assumed that such changes are reversible after samples have been reimmersed in a buffer solution for a sufficient period of time. In this study we characterize the changes associated with fixation of single Xenopus laevis oocytes and their subsequent reimmersion in buffer. Substantial reductions in both T(1) and T(2) values were measured for all compartments of the cell after fixation, with the cytoplasm showing larger changes than the nucleus. After reimmersion in buffer, there were small but statistically significant differences in MR parameters between fresh and reimmersed cells. Experiments with a gadolinium (Gd) contrast agent showed evidence of irreversible changes in the permeability of cellular membranes to small molecules.