13C-urea breath test in Helicobacter pylori diagnosis and eradication. Correlation to histology, origin of ''false'' results, and influence of food intake

Obliterative or constrictive bronchiolitis is characterized by narrowing of the small airways, due to submucosal and peribronchiolar fibrosis, with chronic obstruction. The vast majority of cases of bronchiolitis obliterans are associated with other diseases and only few cases are idiopathic. We report on the main computed tomography (CT) methods used study obliterative bronchiolitis, the CT findings and the differential diagnosis with other diseases. The dynamic study of alveolar ventilation with CT uses inspiratory and expiratory CT or high-resolution CT (HRCT), spiral dynamic CT or HRCT with advanced image display, ultrafast CT. In abnormal cases HRCT shows direct and indirect signs of small airways disease. The most common (> 80%) sign of obliterative bronchiolitis is the so-called mosaic oligohemia, with low attenuating lobules, caused by air trapping and best seen on expiratory CT, associated with blood flow redistribution to more normal lobules; this finding simulates the ground-glass pattern from infiltrative lung disease. Differential diagnosis is more difficult in the presence of true ground-glass patterns associated with diffuse bronchiolar obstruction and also with mosaic oligohemia due to pulmonary vascular disease and pulmonary emphysema. HRCT can distinguish these diseases and dynamic CT is more sensitive than functional tests in detecting regional abnormalities and air trapping. The combination of HRCT, rapid volumetric scanning and advanced image display is a powerful tool study the normal and abnormal features of bronchiolar function and alveolar ventilation.     

Fecal bile acid excretion and composition in response to changes in dietary wheat bran,fat and calcium in the rat

The effect and possible interactive influence of different dietary amounts of wheat bran, fat and calcium on the fecal excretion, concentration and composition of bile acids was studied in Fischer-344 rats. The fecal bile acids were analyzed using gas-liquid chromatography. Dietary wheat bran increased both total bile acid excretion and fecal weight without changes in fecal bile acid concentration. The proportion of fecal hyodeoxycholic acid decreased with increasing dietary fiber, whereas that of lithocholic and deoxycholic acids increased significantly with fiber intake. The percent content of fecal chenodeoxycholic acid did not change. Increasing dietary fat led to an increase in bile acid excretion without changes in either fecal weight or bile acid concentration. In contrast, the level of dietary calcium did not affect the total excretion of bile acids. However, since calcium increased the fecal weight, it consequently diluted bile acids and decreased their fecal concentration. Dietary fat and calcium had no influence on fecal bile acid composition. There were no interactive effects of wheat bran, fat and calcium on fecal bile acids. The finding in this study that dietary fiber, fat and calcium induce significant changes in fecal bile acids may be of relevance to the potential of bile acids to promote carcinogenesis.     

Recovery and characterisation of coloured phenolic preparations from apple seeds

The aim of this study was to investigate whether complexly constituted phenolic extracts from apple seeds may be utilised for the recovery of natural coloured antioxidant preparations, which might serve as potential food or cosmetic ingredients.In a first step, the recovery of phenolic compounds was optimised by varying crucial extraction parameters. A single extraction step at 25 °C using an acetone–water mixture (60:40, v/v) and a solid-to-solvent ratio of 1:8 (w/v) for 1 h was found to be appropriate to achieve both high phenolic yields and antioxidant activities.In a second step, differently produced apple seed extracts and a phloridzin model solution were enzymatically treated by mushroom polyphenol oxidase to investigate the rate of pigment synthesis. Depending on the extraction procedure applied, synthesis rates, pigment yields and colour properties significantly differed. Compared to the phloridzin model solution, extracts recovered from the seeds showed comparable and even better results, thus indicating such preparations to be a promising alternative to synthetic yellow dyes.     

Interpretation of partial discharges at dc voltages

The aim of this paper is to give an overview on partial discharges at dc voltage. A model is presented which describes the stochastic discharge process. The model is experimentally verified for internal discharges and for corona in air. In addition, the classification of discharge patterns is discussed. The 3-dimensional histogram describing the number of discharges depending on the discharge magnitude and on the time to the successive discharge is suggested to be used as a base for discharge recognition at dc voltage. Experimental proof is presented to show the strength of this approach     

Investigation of radiation damage in DNA by using atomic force microscopy

The effect of radiations on supercoiled plasmid DNA has been investigated by using atomic force microscopy (AFM). The DNA molecules were deposited on a substrate and observed by AFM. Alternatively, DNA at different scavenger concentrations was initially exposed to different types of radiations (alpha and X rays) at various doses. After irradiation, fragments (open circular and linearised strands) were observed corresponding to single strand breaks and double strand breaks in DNA. This result indicates the capabilities of AFM for the qualitative detection of strand modifications due to irradiation. The amount of each class of topology enables a quantitative response to be determined for both types of radiation (alpha, X). A value of the radiosensitivity of DNA was obtained as a function of the scavenger concentration. Strong accordance was found between AFM results and those obtained by use of gel electrophoresis. The advantage of AFM in comparison with traditional techniques is the possibility of analysing the radiation effects on one molecule. Indeed, taking the example of alpha particles, it is shown that it is easy to measure the sizes of linear strands by AFM. Such additional or even precise results are difficult to obtain with gel electrophoresis since, in such a case, data are lost through smearing.     

Thermodynamics and phase relations in refractory metal solid solutions containing carbon,nitrogen, and oxygen

The refractory metals Nb, Ta, Mo, and W dissolve C, N, and O by forming interstitial solid solutions. The concentration of these components can be increased or decreased by annealing treatments, depending on the partial pressure of gases such as N₂, O₂, H₂O, CH₄, or CO and on the temperature of the specimen. New results in binary and ternary systems combined with those obtained in the last few years now provide most of the data needed for the thermochemical analysis of the solid solution phases and for the establishment of p-T-c phase diagrams. The mechanisms of the gas-metal reactions and the general feature of the constitution diagrams are similar for all refractory metals. However, marked differences exist between group Va metals niobium and tantalum and group VIa metals molybdenum and tungsten in the absolute values and temperature dependence of the equilibrium pressure of gaseous species and therefore also in the amount of gas absorbed. The data now available for the estimation of the final content of interstitials in solid solution after annealing treatments are compiled and discussed. On leave from the Max-Planck-Institut fur Metallforschung, Institut fur Sondermetalle, Stuttgart, Germany     

Silicon Force Transducer for Extraluminal Measurement of Oviduct Contractile Activity

A miniature, implantable force transducer has been developed for the extraluminal measurement of segmental smooth muscle contractility and has been applied to the oviduct in the Macaca mulatta. The force transducer makes use of a commercially available piezoresistive silicon strain sensor bonded to a flexible metal strip. The device is housed in a tissue compatible, gas sterilizable tubule upon which are placed sutures for subsequent extraluminal attachment to an organ.     

Effect of mine water on rock deformation in coal mines

The paper presents results obtained for the effects of mine water on rocks of Russian coal-bearing sequences. The effects are correlated with a rock-type grouping according to the degree of secondary alteration which the rocks have undergone. Regression analyses performed on the results have enabled a stability factor to be evaluated which permits predictions to be made regarding the stability of rocks in-situ.     

Rißfortschritt in ultrafesten Stählen und deren Schweißverbindungen bei dynamischer Beanspruchung

Crack propagation in ultra-high-strength steels and their welded joints under dynamic loading . Reported are results of investigation into the propagation of cracks in the base metal and weld metal of an ultra-high-strength steel. The material used in the investigations was a Ni? Co? Mo? alloy maraging steel with a yield point of 170 kp/mm². The steel was arc welded and TIG welded. The joints exhibited a drop of static strength in the range of 5 to 8 percent related to the base metal. Under zero-to-tension stress cycles the fatigue strength corresponded that of other high-strength steels, under tension-compression stress cycles the steel exhibited a higher fatigue strength. It was possible to show striations with the aid of scanning microscopy. Comparing the track propagation calculated in the microscopic range with the results obtained from the crack growth curves produced approximate agreement.