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Subhadra Chaudhuri Abdulla Mondal Arun Kumar Pal 《Microscopy research and technique》1990,14(4):329-334
The microstructure and growth of ZnTe films deposited onto glass and freshly cleaved NaCl substrates are carefully studied by a TEM. Effect of different stimulator on the grain growth is also described. 相似文献
23.
Large‐scale fading (LSF) between interacting nodes is a fundamental element in radio communications, responsible for weakening the propagation, and thus worsening the service quality. Given the importance of channel‐losses in general, and the inevitability of random spatial geometry in real‐life wireless networks, it was then natural to merge these two paradigms together in order to obtain an improved stochastical model for the LSF indicator. Therefore, in exact closed‐form notation, we generically derived the LSF distribution between a prepositioned reference base‐station and an arbitrary node for a multi‐cellular random network model. In fact, we provided an explicit and definitive formulation that considered at once: the lattice profile, the users' random geometry, the effect of the far‐field phenomenon, the path‐loss behavior, and the stochastic impact of channel scatters. The veracity and accuracy of the theoretical analysis were also confirmed through Monte Carlo simulations. 相似文献
24.
UA Temann B Prasad MW Gallup C Basbaum SB Ho RA Flavell JA Rankin 《Canadian Metallurgical Quarterly》1997,16(4):471-478
Mucus hypersecretion and plugging of lower respiratory tract airways contributes to the morbidity and mortality associated with asthma. Interleukin (IL)-4 plays a putative role in some forms of asthma. Thus, transgenic mice that overexpress murine IL-4 selectively within the lung were used to study the effect of IL-4 on mucus glycoprotein gene expression and mucin release. Histologic examination of lung sections from IL-4 mice revealed that nonciliated epithelial cells from conducting airways were hypertrophic, due at least in part to the accumulation of mucus glycoprotein. The cytoplasm of these cells stained positively for glycoproteins using mucicarmine, alcian blue (AB), and periodic acid-Schiff (PAS). Ciliated cells were also enlarged but did not show any mucin-specific staining. Inclusion granules typically found in nonciliated (Clara) cells of control mice were absent in the IL-4 transgenic mice. Northern blot analysis of total RNA from lung tissue revealed that the expression of the MUC5AC, but not MUC2, mucin gene was distinctly upgraded in IL-4 transgenic mice compared to transgene-negative controls. In addition, a 5- to 10-fold increase in AB- and PAS-positive material was found in lavage fluid from IL-4 overexpressing mice compared to transgene-negative controls. Thus, the overexpression of IL-4 locally within the lung enhances mucus glycoprotein synthesis by altering gene expression, results in the accumulation of mucus glycoprotein in nonciliated epithelial cells, and induces the release of mucus into the airway lumen. We therefore hypothesize that the overproduction of mucus seen in some patients with asthma may be a direct result of the action of IL-4 within the inflamed lung. 相似文献
25.
R Zanini M Tarantini V Cerri C Jacobello D Bellotti S Lancetti S Scalchi C Groli UA Bianchi 《Canadian Metallurgical Quarterly》1998,13(2):106-110
The pattern of anatomical features of the brain revealed by magnetic resonance imaging (MRI) is described in six patients incidentally identified as having acallosal brains. The complex of morphological features associated with complete agenesis of the corpus callosum included lateral displacement of slitlike anterior horns of the lateral ventricles (bullhorn-like shape), dilatation of the posterior horns of the lateral ventricles, absence of the septum pellucidum, lateral displacement of the cingulate gyri, complete separation of fornices and the presence of the anterior commissure and longitudinal callosal bundles (Probst's bundles). No compensatory enlargement of the anterior commissure was seen in the patients. The planimetrically measured cross-sectional areas of the anterior commissures were between 2.0 and 4.2 mm2 (mean 3.1) (in ten normal subjects they were 4.5, SD 0.4; range 3.8-5.2 mm2) and were reduced in four and normal in two patients. Inconstant morphological features were an absence of the posterior commissure and a radial pattern of the sulci and gyri on the medial aspect of the hemispheres. Conventional clinical testing revealed no abnormalities except a slight impairment of walking heel-to-toe in two patients. None of the patients had subjective restrictions of activities of daily life, which shows the efficacy of unknown compensatory processes. 相似文献
26.
UA Marbet 《Canadian Metallurgical Quarterly》1994,124(11):439-451
Diarrhea is still one of the most frequent causes of death and poses many diagnostic and therapeutic problems. Whereas the etiology of acute diarrhea is mainly infectious, the cause of chronic diarrhea is much more multifarious and thus more difficult to diagnose. The etiology of acute diarrhea as well as the sense and nonsense of diagnostic procedures and therapeutic possibilities are discussed. A rational and practical concept for evaluation of chronic diarrhea is presented. 相似文献
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Primary sclerosing cholangitis (PSC) is generally associated with ulcerative colitis (UC). The disease typically progresses slowly, but ultimately, and leads to cirrhosis, liver failure or bile duct cancer. PSC patients with simultaneous ulcerative colitis are also at higher risk for colorectal cancer. At the present time, there is no effective treatment for PSC, although preliminary data show encouraging results after treatment with ursodeoxycholic acid. However, there are no data concerning the delay or prevention of progress of the disease with this drug, because follow-up time is not yet long enough. Isolated bile duct strictures should be treated endoscopically. The possible effect of proctocolectomy on the course of PSC is controversial. Liver transplantation is the therapy of choice for PSC in its final stage. The 5-year survival rate (89%) is significantly better than after transplantation for other indications. Patients with ulcerative colitis have to be followed up by lifelong colonoscopy. Although the course of UC after transplantation is mostly asymptomatic, these patients are at higher risk for colorectal cancer. 相似文献
29.
JR Veraart C Gooijer H Lingeman NH Velthorst UA Brinkman 《Canadian Metallurgical Quarterly》1998,719(1-2):199-208
The molecular karyotype of a series of Giardia lamblia isolates representing the two major genotypes (Groups 1 and 3) was generated by assigning 13 genetic markers to chromosomes separated by pulsed-field gel electrophoresis. The co-localization identified five linked groups of genetic markers in Group 1 isolates. For each of the five linkage groups, there were up to four size variants that hybridized with the same genetic markers. Long range physical maps of the regions flanking the low copy number genetic markers indicated that these size variants were homologous chromosomes. The linkage groups were similar in Group 1 and 3 isolates. The core of each chromosome was stable while the subtelomeres were variable. The location of the ribosomal DNA repeats was variable among the different isolates and they were found in the subtelomeric regions of any of the five linkage groups. The data suggest a functional ploidy of at least four. Hypervariable subtelomeric regions of homologous chromosomes provide the structural basis of the chromosome size heterogeneity that is characteristic of G. lamblia. 相似文献
30.
Measurements were made of zinc levels in saliva, whole blood and plasma as well as copper levels in plasma by atomic absorption spectrophotometry. The mean zinc concentration (in ppm) was 0.478 (n = 136) in resting mixed saliva, 0.046 (n = 36) in parotid saliva, 6.41 (n = 145) in whole blood and 0.87 (n = 145) in plasma. The whole blood zinc levels were significantly lower in females than in males (P less than 0.001). Females and blood donors (males) had a significantly (P less than 0.001) higher Cu:Zn ratio than males (non-donors). It would thus appear, first, that the local effect of salivary zinc cannot be assessed simply from the concentration of zinc in stimulated parotid saliva since about nine-tenths of the zinc in resting mixed saliva is derived from other sources and, second, that the Cu:Zn in plasma is the most eligible variable for detecting sub-clinical Zn deficiency. 相似文献