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.     

HMPAO brain SPECT in acute carbon monoxide poisoning

Technetium-99m-hexamethylpropylene amine oxime (HMPAO) brain images with fanbeam SPECT, in combination with surface three-dimensional display, were used to detect basal ganglion and cerebral cortex anomalies in the acute phase of carbon monoxide (CO) poisoning. METHODS: Ten patients, aged 16-29 yr, with acute CO poisoning and no past history of neurologic disorders were enrolled in this study. After oxygen treatment, all 10 patients were investigated using 99mTc-HMPAO brain images with fanbeam SPECT and surface three-dimensional display. Meanwhile, 6 of 10 patients also received a brain CT scan. RESULTS: CT scan findings were negative in all 6 patients. Fanbeam SPECT demonstrated unilateral or bilateral hypoactivity of basal ganglia in 6 patients. Local hypoactivity anomalies were found in the brain cortex of 7 patients, using surface three-dimensional display of the brain. Only 2 of 10 patients had normal 99mTc-HMPAO brain images. CONCLUSION: This study suggests that, in comparison with traditional brain imaging techniques, 99mTc-HMPAO brain imaging with fanbeam SPECT in combination with surface three-dimensional display is a better tool for early detection of regional cerebral anomalies in acute CO poisoning.     

The quality of adolescent friendships: long-term effects?

Retinoic acid (RA) has been implicated in cardiac morphogenesis by its teratogenic effects on the heart, although its role in normal cardiogenesis remains unknown. To define the parameters of RA action in cardiac morphogenesis, we analyzed the patterns of ligand synthesis, response, and inactivation in the developing mouse heart. Activation of a lacZ transgene controlled by an RA response element (RARE) was compared to the localization of the retinaldehyde-oxidizing dehydrogenase RALDH2, the earliest RA synthetic enzyme in the mouse embryo, and to the expression of a gene encoding an RA-degrading enzyme (P450RA). We observed that RALDH2 localization and RA response were virtually superimposable throughout heart development. Initially, both RALDH2 and RARE-LacZ activity were restricted to the sinus venosa in unlooped hearts, but were high in the dorsal mesocardium, while P450RA expression was restricted to the endocardium. Later stages were characterized by a sequential, noncontiguous progression of RALDH2 accumulation and RA response, from the sinus venosa to atria, dorsal-medial conotruncus, aortic arches, and the epicardium. This dynamic pattern of RA response was a direct result of localized RALDH2, since hearts of cultured embryos were uniformly competent to respond to an exogenous RA challenge. These observations support a model in which the influence of endogenous RA on heart development depends upon localized presentation of the ligand, with only limited diffusion from the source of its synthesis.     

Non-penetrance and late appearance of polyps in families with familial adenomatous polyposis

One case of non-penetrance of the familial adenomatous polyposis (FAP) gene at 59 years of age and late onset of polyps on endoscopy and biopsy in this and two other families is described. Screening protocols should include dental screening as well as indirect ophthalmoscopy and endoscopy to detect minimal manifestations of the gene. In the absence of a specific DNA predictive test, bowel screening should continue well beyond 30 years of age.     

Geometric and mechanical properties of the coracoacromial ligament and their relationship to rotator cuff disease

One of the most common causes of pain and disability in the upper limb is inflammation of the rotator cuff tendons. When no significant bony abnormality exists in the surrounding structures, the coracoacromial ligament has been implicated as a possible cause of impingement on the cuff tendons. Geometric and mechanical properties of 20 coracoacromial ligaments, 10 from shoulders with rotator cuff tears and 10 from normal shoulders, were accurately determined. In comparing rotator cuff tear and normal specimens, statistically significant changes in geometric properties were measured in the lateral band, but not in the medial band, of the ligament. The lateral band, which is the region most likely to impinge on the rotator cuff, was shorter and had a larger cross-sectional area in specimens with rotator cuff tears. Although there were no statistical differences in structural properties of the ligament between normal and rotator cuff tear groups, significant changes were evident in material properties. Previously reported histologic differences in the ligament in shoulders with rotator cuff tears are supported by the decreased material properties measured in the current study. Whether the differences in the coracoacromial ligament cause impingement or are due to impingement is still unknown at this time.