Temperature-modulated differential scanning calorimetry studies of the structure of bulk and film GexAsyS60 chalcogenide glasses

The recent novel temperature-modulated differential scanning calorimetry (TA Instruments MDSCTM) technique has been applied to the measurement of thermal properties of GexAsyS60 chalcogenide glasses in the glass transition region in bulk glasses and in their thin films. The reversing and non-reversing heat flows through the glass transformation region during both heating and cooling schedules were measured and the values of the parameters, Tg, ΔH, Cp and ΔCp, which characterize the thermal events in the glass transition region, were determined. The structurally determined parameters, Tg, ΔH, Cp and ΔCp, reveal significant changes with composition because in the GexAsyS60 glasses the average coordination number, 〈r〉, increases from 2.4 to 2.8 with increasing x from 0 to 40 at% Ge. A maximum in Tg, ΔH and Cp and a minimum in the heat capacity change, ΔCp, at Tg occur near the composition for which x≈30 at% Ge. These extrema which appear in both films and bulk glasses are ascribed to a change in the network function of Ge atoms replacing As atoms in a covalent network. Recent structural models for chalcogenide glasses have been considered to explain the observed thermal properties. This revised version was published online in November 2006 with corrections to the Cover Date.     

Application of elastic mid-infrared light scattering to the investigation of internal gettering in Czochralski-grown silicon

The influence of the internal gettering process on the large-scale defects in Czochralski-grown boron-doped single-crystal silicon is investigated by low-angle mid-infrared light scattering. The large-scale defects in the as-grown material and crystals subjected to the internal gettering procedure are classified. The applicability of low-angle light scattering in laboratory investigations and in the industrial inspection of the operations in an internal gettering production cycle is demonstrated. Fiz. Tekh. Poluprovodn. 31, 1158–1163 (October 1997)     

Should patients with sleep apnoea/hypopnoea syndrome be diagnosed and managed on the basis of home sleep studies?

The purpose of this study was to analyse the validity and the economic efficiency of a portable monitor of respiratory parameters (PMRP), used in a home setting for the diagnosis of sleep apnoea/hypopnoea syndrome (SAHS). Eighty nine patients with suspected SAHS were studied in two settings: in the sleep laboratory using full-polysomnography (full-PSG); and at the patient's home using a PMRP. In the home setting, 50 patients were assisted by a technician and 39 set up the equipment themselves. SAHS (apnoea/hypopnoea index (AHI) >10 events x h(-1) by means of full-PSG) was diagnosed in 75 of the 89 patients. An acceptable agreement was obtained between the AHI measured by full-PSG and PMRP, according to the Bland and Altman method of concordance (mean bias 2.56; 95% confidence interval 3.25). Sensitivity and specificity of PMRP were adequate for diagnostic purposes; however, their values rely on the prior PMRP-AHI cut-off point selected with reference to full-PSG-AHI >10. The clinical therapeutic decision taken after PMRP agreed with that taken with full-PSG in 79 patients (89%). Although 10% of the studies with an individual set-up needed repetition, both of the domiciliary modalities (with and without a technician's intervention) were, economically, about three times more efficient than full-PSG. In conclusion, we believe that patients with a suspected sleep apnoea/hypopnoea syndrome should initially be studied in a home setting with a portable monitor of respiratory parameters, since it is a reliable method with an acceptable cost-effective profile.     

In vitro triggering of somatic mutation in human naive B cells

During T cell-dependent immune response, germinal center B cells accumulate somatic mutations in their Ig V(D)J genes and give rise to affinity-selected B cells. We tested several culture conditions for triggering somatic mutation in human tonsillar naive slgD+CD23+ cells after cross-linking their membrane Igs. CD40 activation, in the presence of exogenous cytokines (IL-2, IL-4, and IL-10), induced proliferation and isotype switch without somatic mutation. In contrast, after coculture with anti-CD3-activated cloned T cells, somatic mutation accumulated in a fraction of naive B cells. Mutations included shared as well as independent events in clonally related sequences, allowing reconstitution of genealogic trees generated in vitro. Naive tonsillar B cells sorted for slgD expression can be induced to mutate their Ig V(H) gene upon coculture with activated T cells, thereby providing a model to study somatic hypermutation in vitro.     

95W-Ni-Fe 合金工艺缺陷的 SAM 和 XPS 分析

藉助扫描俄歇探针、Ｘ射线光电子谱等分析了９５Ｗ－Ｎｉ－Ｆｅ合金碳污染和氧化的本质。发现，碳污染试样中碳的化学状态主要为石墨，少量为铁或镍的有机化合物，这些物质的界面富集使材料脆化。钨合金氧化后，氧大量富集于钨／粘结相界面，使沿着该界面的断裂更容易发生。     

Vibrational instability of the charged interface of immiscible electrically conductive liquids

This paper shows that, in an electrostatic field normal to the flat interface of two viscous electrically conductive liquids, an oscillatory instability of the interface with periodically increasing amplitude can be produced when the electrical conductivity of the upper liquid is substantially greater than that of the lower one. Results are obtained by numerical analysis of the dispersion equation. Pis’ma Zh. Tekh. Fiz. 23, 32–36 (November 12, 1997)     

Non-smoking policies and practices in Norwegian delivery units in 1994

OBJECTIVE: To determine the number of delivery units in Norway that have become smoke free for employees and patients. DESIGN: A pre- categorised questionnaire was sent in September 1994 to the physician or midwife responsible for each of the 68 delivery units in the country. MAIN OUTCOME MEASURES: Hospital smoking policies, reported difficulties in implementation, use of nicotine replacement therapy in patients, and provision of information on tobacco-related health hazards to patients. RESULTS: Fifty-six units (82.3%), accounting for 93% of all deliveries in Norway in 1993, responded. Of these, 42 (75%) were smoke-free for employees, and 33 (59%) for patients. Nearly all had become smoke-free after 1990. No significant difference was seen according to type or size of delivery unit. No difficulties in the implementation of policies restricting smoking were reported. Thirty- one (55%) routinely informed patients of the health implications of smoking during pregnancy. Two units offered nicotine replacement therapy to patients. CONCLUSION: Most Norwegian delivery units were smoke-free for both employees and patients. Provided that the recent trend toward adoption of smoke-free policies continues, all delivery units in Norway should be smoke-free by 1997-1998.




     

Computation model of corrosion-fatigue crack growth in thin metallic plates

A computation model of corrosion-fatigue crack growth in thin metallic plates is suggested based on well-known theoretical concepts of fatigue and corrosion fracture and some assumptions. A physicochemical model of this process is constructed, and mathematical relations that describe the kinetics of crack propagation are established. The model agrees with well-known experimental data.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 1, pp. 30–34, January–February, 1994.     

Renal sodium excretion after oral or intravenous sodium loading in sodium-deprived normotensive and spontaneously hypertensive rats

Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats that had been on a low sodium diet for 3 days were given 1.5 mmol sodium chloride kg-1 body weight either orally or intravenously. The rats receiving an oral sodium load showed a greater natriuresis than those receiving the same saline load intravenously. No increase of renal sodium excretion was observed when the rats received a hypertonic mannitol solution orally. The cumulative sodium excretion during the 8 h following oral loading was two to three times larger in SHR than in WKY, whereas no difference between strains could be demonstrated after giving saline intravenously. Furthermore, after switching from normal to low sodium diet the rate of decrease of renal sodium excretion was greater in SHR than in WKY rats. It is proposed that there exists a gastrointestinal sensory mechanism for sodium controlling the renal sodium excretion. Furthermore, it is suggested that the function of this mechanism differs between SHR and WKY.     

Rat heart-aorta cluster transplantation: a novel model to study transplant rejection

The purpose of this study was to develop a microsurgical cluster model of heart plus entire thoracic aorta transplantation and to compare it to the isolated model of heart transplantation as a tool to study transplant rejection. Thirty-six syngeneic (DA x DA and Lew x Lew) and allogeneic (DA x PVG and DA x Lew) cluster heart-aorta transplants were compared to 43 syngeneic and allogeneic isolated heart grafts. Graft survival, recipient survival and histological data on myocardial and aortic tissues were assessed. There was no statistically significant difference in graft survival between the two models studied (P > 0.05). In the cluster transplants, the aortic component was spared the severity of acute rejection noted for the myocardial counterpart. In conclusion, the results demonstrated that the cluster model was technically feasible and highly reproducible. Additionally, it was possible to apply this model to the study of experimental allograft rejection using novel immunosuppressants. The success of the cluster model in strongly mismatched transplant strain combinations underscores its potential for application in slower rejection combinations, making it particularly suited for chronic rejection studies. The inherent capacity for sampling a broader range of vessel sizes in one animal makes the cluster model more suitable than the isolated models of aorta or heart for application to experimental protocols.