The formation of amorphous and crystalline condensates from the vapour phase

An electron microprobe technique is described for determining the thickness of SiO₂ and Si₃N₄ in wafers and devices. The technique is based on the measurement of oxygen and silicon X-ray intensities at 2.5 kV and 10 kV through the nitride overlay. At the lower accelerating voltage, both intensities decrease with increasing nitride thickness owing to absorption and silicon distribution in depth. The SiO₂ thickness, however, is obtained by measuring the oxygen X-ray intensity at the higher voltage (10 kV), because at this voltage the oxygen intensity is not dependent on the nitride thickness.Empirical relationships expressing Si₃N₄ thickness in terms of Si and O X-ray intensities and SiO₂ thickness are derived.     

Post-secretory deiodination of iodothyronines released from normal human thyroid cells in vitro

The Salmonella strains described in this paper were isolated from clinical and environmental sources in Togo (West Africa). All strains belong to subgenus I of the genus Salmonella. 1. Salmonella kodjovi 47:c:-, Supplement No. XVII (1974), isolated from stool specimen 2. Salmonella dadzie 51:1, v:e, n, x, Supplement No. XVII (1974), isolated from stool specimen 3. Salmonella mono 4, 12:1, w:1, 5, Supplement No. XVII (1975), isolated from pig droppings 4. Salmonella chincol var. s-, monophas. 6, 8:g, m:-, Supplement No. XVIII (1975), isolated from lizard intestines 5. Salmonella chicago var. i+, 28:r, i:1,5, Supplement No. XVIII (1975), isolated from stool specimen 6. Salmonella havana var. s+, 36+, 13,23:f,g,s:-, Supplement No. XVIII (1974), isolated from stool specimen 7. Salmonella elisabethville var. 15+, 3,15:r:1,7, isolated from lizard intestines.     

Antibody response to Engerix-B and Recombivax-HB hepatitis B vaccination in end-stage renal disease

Recombivax-HB (REC) and Engerix-B (ENG) are FDA-approved vaccines for hepatitis B virus (HBV) in end-stage renal disease (ESRD). This study compares antibody response rates between them in routine clinical practice. Patients completing the recommended 40 mug dose of REC (3 doses) or ENG (4 doses) between January 1, 2000 to April 30, 2003 were eligible. Patients with prior positive HBV surface antigen (HBsAg) or antibody (HBsAb) test results were excluded. The conversion rate and persistence of protective titer (HBsAb titer>or=10 IU/mL) were tracked for 1 year. A supplemental analysis of a one-to-one matched patient sample was also performed. REC patients (N=885) were older, had longer dialysis vintage, and had a larger proportion of whites than ENG patients (N=13,661). Cumulative conversion response was greater in ENG (58%) than REC (40%) at 1 year (p<0.0001). The odds ratio for response to ENG compared with REC was 1.96 (95% limits: 1.56, 2.45; p<0.0001) adjusted for age, gender, race, diabetes, vintage, BSA, hemoglobin, and eKt/V. Persistent protective HBsAb after 1 year was 77% (ENG) vs. 53% (REC). HBsAg was positive in 208 ENG patients (1.5%) with all but 1 because of transient, vaccine-related antigenemia. The difference in conversion response favoring ENG persisted in a one-to-one sample matched for age, gender, race, modality, and dialysis vintage. The study found higher seroconversion response to ENG compared with REC at several time points up to 1 year. Protective HBsAb disappeared in 23-47% of patients 1 year later, validating CDC recommendations to re-test HBsAb yearly. The observed difference in response rates may be related to the extra ENG dose given at the second month (0, 1, 2, 6 regimen). The study raises a hypothesis that requires confirmation in a prospective clinical trial.     

Rapid spectrophotometric method for determining ornithine decarboxylase using 2,4-dinitrofluorobenzene

A sensitive spectrophotometric micromethod was developed for estimation of ornithine decarboxylase (ODC) activity in animal tissues. Distinct increase in the enzymatic activity was found in regenerating and malignant liver tissues as well as in hepatomas G-27 and G-46 as compared with the corresponding tissues of control animals. The linear relationship between the optic density and content of dinitrophenyl putrescine was maintained over the range of 0 to 150 nmol per a sample. The ODC pH optimum was observed within the zone pH 6.4-6.8; it did not depend on the nature of the buffer, used for tissue homogenization. The recovery of putrescine added into the sample was equal to 102.97 +/- 2.22%. The method had an error less than 3%, its sensitivity was 0.1 nmol/sample and the reproducibility was about 100%.     

Physical activity and plasma lipoprotein lipid concentrations in men

Twenty-three apparently normal untrained men aged 20--55 participated in a 4-month self-regulated training programme ending in a marathon run. Fasting plasma and lipoprotein lipid concentrations, adipose tissue lipoprotein lipase activity, anthropometric data, alcohol consumption, smoking habits, weekly mileage run and performance on a bicycle ergometer were recorded before and after the training period. Training induced an increase in high density lipoprotein cholesterol (HDL-C) concentration which was not directly related to concomitant decreases in mean very low density lipoprotein cholesterol (VLDL-C) concentration or mean total skinfold thickness. The degree of the changes in VLDL lipids and HDL-C levels were related to pretraining values, and changes in HDL-C and VLDL triglycerides (VLDL-TG) were also associated. Initial total skinfold thickness correlated inversely with the change in VLDL-TG levels during training. The pretaining concentration of VLDL-C was related to the corresponding value for HDL-C after training. The magnitude of exercise-induced changes in VLDL-C and HDL-C levels are more related to pre-training levels than to changes in measured exercise parameters, indices of obesity or adipose tissue lipoprotein lipase activity. However, the level of adiposity of subjects at the beginning of the study influenced the response of VLDL-TG levels to increased physical activity. The data suggest that VLDL contributes to the increase in HDL-C levels with exercise but is not the major source of the increment.     

便携式X射线荧光光谱仪检测贫铀棒材表面镍锌镀层厚度

为了确保贫铀棒材表面防腐性能满足使用要求,需要准确地测量产品表面的镍镀层和锌镀层厚度。采用便携式X射线荧光光谱仪(PXRF)对贫铀棒材表面双镀层的各层厚度进行检测,实现了对镍镀层和锌镀层厚度非破坏性的测量。选用特征谱线强度分布均匀的镀层样品和未镀镀层的贫铀基体样品,采用PXRF检测,结果表明,基体射线对检测谱线无干扰。分别选取相同厚度镍镀层、不同厚度锌镀层的样品,相同厚度锌镀层、不同厚度镍镀层的样品,以及镍镀层、锌镀层厚度均不相同的样品,采用PXRF进行检测,结果表明,实验方法可识别相同基体上不同厚度的镍镀层和锌镀层,可实现镍锌组合镀层中两种镀层厚度的同时测量。根据贫铀棒材样品结构特点和镍镀层和锌镀层厚度的技术要求,设计制作了对比试样,分别绘制贫铀棒材样品镍镀层和锌镀层厚度与其对应特征峰强度的校准曲线,结果表明,校准曲线线性相关系数r均不小于0.999 4。采用实验方法检测贫铀棒材样品表面镍镀层和锌镀层厚度,同时在任意圆周上均匀地取6个检测点,采用金相显微镜法进行检测求得平均值,结果表明,实验方法测定结果相对标准偏差(n=6)不大于5.1%;与金相显微镜法基本一致,两种方法差值为-1.57~1.70 μm。     

Retroperitoneal germinoma marked by elevated serum lactic dehydrogenase

A case of primary retroperitoneal germinoma is presented in which markedly elevated serum lactic dehydrogenase levels were present before diagnosis, but declined to normal with abdominal irradiation. It is the first report of lactic dehydrogenase serving as a tumor marker in germinoma.     

9-azidoacridine, a new photoaffinity label for nucleotide- and aromatic-binding sites in proteins

The effect of the photolytic reagent 9-azidoacridine, optionally 3H-labelled, was studied both kinetically and structurally on nine different enzymes, namely alpha-chymotrypsin, lactate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase, alcohol dehydrogenase, alanine dehydrogenase, D-amino acid oxidase, ribonuclease A, alkaline phosphatase and alpha-amylase. Dark inhibition was observed in several cases. The concentration of the inhibitor ranged from 0.2 microM to 0.67 microM and demonstrated competitive kinetics with nucleotide cofactors when present. All concentrations of inhibitor showed increased inhibition on photolysis. Examination of the oligopeptides from hydrolysis of the covalently 3H-labelled derivative in conjunction with known amino acid sequence and tertiary structure established that the primary site of interaction in those cases for which the tertiary structure was available involved the active-site region. The above results in conjunction with those obtained with the structural analogues 9-aminoacridine and 9-amino-1,2,3,4-tetrahydroacridine established that this reagent acts as a molecular probe of aromatic- and, in particular, nucleotide-binding sites. This reagent provides a further additional method for studying the nucleotide cofactor domain.     

Peripheral neuropathies in diabetes

Peripheral neuropathy in diabetes remains a difficult management dilemma. The clinical manifestations may vary widely. Polyneuropathies develop with increasing duration of disease, and a thorough understanding of the clinical manifestations, including sensory, motor, and autonomic deficiencies, helps guide diagnosis and treatment. A multidisciplinary approach emphasizing preventive care and timely intervention can decrease morbidity significantly and improve the quality of life for the patient. Properly fitting shoes and avoidance of foot trauma are cornerstones of preventive management. Strict control of serum glucose can alter the course of peripheral neuropathies. This control can be accomplished with a strict insulin regimen or pancreatic transplant. Further research is needed to increase knowledge about peripheral neuropathies in diabetes and aid the physician with new treatment options.