Gastric erosions: radiological and endoscopic aspects

Varioliform gastric erosion is a common lesion which can be reliably diagnosed radiologically. The diagnosis was established in 27 (1.7%) of 1,600 detailed radiological examinations made in 1975. There was a good correlation with gastroscopic findings.     

A detection system for energetic light heavy ions

A light heavy ion detection system which consists of a gas-filled ionization chamber (IC) connected to a scattering chamber via a time-of-flight (TOF) system has been constructed. The entrance window of the IC has an area of 14 × 40 cm², the active depth is 115 cm. Filled with CF₄ at a pressure of 350 Torr, the energy range for ¹²C and ⁴⁰Ar is 5–20 MeV/A and 6–30 MeV/A, respectively. The TOF system consists of two parallel plate avalanche counters with a flightpath of 70 cm in between. The IC has been tested with ¹²C ions at an energy of 39 MeV. The energy resolution of the IC (1.1%) is mainly determined by the energy straggling in the foils of the TOF system and the ionization chamber. The energy-loss resolution is 3.5%, the horizontal position resolution varies between 6 and 20 mm and the vertical position resolution is 2 mm. The time resolution of the TOF system ranges from 800 ps for ⁴He at 5.0 MeV, to 280 ps for ²⁸Si at 55 MeV.     

PH值的实时控制

在化学分析和化工生产许多场合,需要严格控制溶液的PH值变化。本文首先设计了一种比较较简单的计算机控制系统,适用于一些对PH值变化要求不是很严的场合,随后从理论上设计了一种自适应控制系统,该系统对于不同的环境以及外部随机干扰,都可使被控对象的PH值最终维持在某一期望值上。该系统有助于提高化学分析和化工生产的自动化程度,具有一定的实用价值。     

Understanding of resonance phenomena on a catalyst under forced concentration and temperature oscillations

Resonance is an interesting phenomenon that may be observed for reactions on catalytic surfaces during periodic forcing of operating variables. Forcing of the variables for non-linear systems may result in substantially changed time averaged behaviour. These resonance phenomena have been observed experimentally by coincidence rather than by systematic analysis. It is not clear for what type of reaction kinetics such behaviour may be expected and predictions are therefore impossible. Clearly, this forms a serious obstacle for any practical application. In this work we set out to analyse the nature of resonance behaviour in heterogeneously catalysed reactions. A Langmuir Hinshelwood microkinetic model is analysed. It is demonstrated that for weakly non-linear forcing variables — as inlet concentrations — forcing leads to resonance phenomena in terms of the reaction rate only in case high total surface occupancies exist in the steady state. In contrast, forcing of strongly non-linear variables — like temperature — may give rise to resonance phenomena for both low and high surface occupancies. Necessary conditions for resonance to occur are derived. The analysis of resonance phenomena is greatly simplified by the availability of explicit analytical expressions as can be derived from Carleman linearization. We will demonstrate the merits of Carleman linearization as compared to numerical integration.     

Physical localization of the flocculation gene FLO1 on chromosome I of Saccharomyces cerevisiae

The genetics of flocculation in the yeast Saccharomyces cerevisiae are poorly understood despite the importance of this property for strains used in industry. To be able to study the regulation of flocculation in yeast, one of the genes involved, FLO1, has been partially cloned. The identity of the gene was confirmed by the non-flocculent phenotype of cells in which the C-terminal part of the gene had been replaced by the URA3 gene. Southern blots and genetic crosses showed that the URA3 gene had integrated at the expected position on chromosome I. A region of approximately 2 kb in the middle of the FLO1 gene was consistently deleted during propagation in Escherichia coli and could not be isolated. Plasmids containing the incomplete gene, however, were still able to cause weak flocculation in a nonflocculent strain. The 3′ end of the FLO1 gene was localized at approximately 24 kb from the right end of chromosome I, 20 kb centromere-proximal to PHO11. Most of the newly isolated chromosome I sequences also hybridized to chromosome VIII DNA, thus extending the homology between the right end of chromosome I and chromosome VIII to approximately 28 kb.     

Diuretics: role of sodium balance

Diuretics are commonly prescribed for a wide variety of clinical problems, including hypertension, extracellular volume excess, and disorders of calcium metabolism. Although natriuresis with altered sodium balance is not always the therapeutic goal, this feature of the diuretics is essential for optimal results, irrespective of the clinical problem.     

Relations between oil,nitrogen, and gossypol in cottonseed kernels

Summary A study was made of the relations between oil, nitrogen, and gossypol contents of cottonseed kernels from the seed of eight commercial varieties of cotton grown at 13 locations during three years. Both variety of seed and environment had a highly significant influence on each constituent whether expressed as percentage of the kernel or as weight of constituent per 100 kernels. Each variety showed a significant positive correlation between oil and gossypol and significant negative correlations between oil and nitrogen and between gossypol and nitrogen, on the basis of percentage-constituent in the kernel. The amount of both oil and nitrogen elaborated in the kernel tends to be related to the size of the kernel; each of these constituents increases with increased kernel size. The highly significant positive relationship between grams of oil and grams of gossypol per 100 kernels which is evident even when nitrogen is held constant can be explained on the basis that these two constituents are synthesized during the same stage of seed development. Rainfall or temperature had no significant over-all influence on the nitrogen content of the kernels. Grams of nitrogen per 100 kernels showed a significant negative correlation with mean minimum temperature for 5 of the varieties but was not significantly correlated with total rainfall during the maturation period for any of the varieties. Grams of oil and gossypol per 100 kernels tended to increase with increasing rainfall and decrease with increasing mean temperature. The ratio of nitrogen to gossypol is negatively correlated with the oil content of the kernels. The variation attributed to varietal influence decreases as the oil content of the kernel increases. It is postulated that high ratios are desirable for the production of meals containing a low free-gossypol content. Presented before the American Oil Chemists’ Society, Houston, Tex., April 23–25, 1956. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

RRR-Tocopherols and their Acetates as a Possible Scavenger of Free Radicals Produced in the Skin upon UVA-Exposure – An in vivo Screening Method

RRR-tocopherols currently draw attention as constituent of cosmetic preparations a. o. to prevent damage by over-exposure to sunlight. Because they only absorb part of the UVB and are transparent to UVA, their skin protective activity is supposed to be based on scavenging of reactive intermediates formed by ultraviolet radiation. To investigate this possibility, an in vivo method was developed. This is based on the determination of irreversible binding to epidermal DNA/RNA, proteins and lipids, of reactive intermediates formed by photodecomposition of a xenobiotic in the skin. The results support the conclusion that RRR-tocopherols can indeed scavenge reactive intermediates which are formed upon UV-exposure in the skin. RRR-tocopherol acetates also are active in this respect but only after pretreatment for some days (possibly because enzymatic hydrolysis of these compounds is a prerequisite).