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The relationship between fracturing and fracture filling in opening-mode fractures in the Triassic Buntsandstein in the Lower Saxony Basin (LSB; NW Germany) has been studied by an integration of petrographic and structural analysis of core samples, strontium isotope analysis and microthermometry on fluid inclusions. This revealed the relationship between the timing of the fracturing and the precipitation of different mineral phases in the fractures by constraining the precipitation conditions and considering the possible fluid transport mechanisms. The core was studied from four different boreholes, located in different structural settings across the LSB. In the core samples from the four boreholes, fractures filled with calcite, quartz and anhydrite were found, in addition to pore-filling calcite cementation. In boreholes 2 and 3, calcite-filled fractures have a fibrous microstructure whereas in borehole 1, fractures are filled with elongate-blocky calcite crystals. Anhydrite-filled fractures have, in all samples, a blocky to elongate-blocky microstructure. Fractures that are filled with quartz are observed in borehole 2 only where the quartz crystals are ‘stretched’ with an elongated habit. Fluid inclusion microthermometry of fracturing-filling quartz crystals showed that quartz precipitation took place at temperatures of at least 140°C, from a fluid with NaCl–CaCl2–H2O composition. Melting phases are meta-stable and suggest growth from high salinity formation water. Strontium isotopes, measured in leached host rock, indicate that, in boreholes 2 and 3, the fluid which precipitated the calcite cements and calcite-filled fractures is most likely locally derived whereas in borehole 1, the 87Sr/86Sr ratios from the pore-filling cements and in the elongate-blocky calcite-filled fracture can only be explained by mixing with externally derived fluids. The elongate-blocky anhydrite-filled fractures, present in boreholes 1, 3 and 4, precipitated from a mixture of locally derived pore fluids and a significant quantity of fluid with a lower, less radiogenic, 87Sr/86Sr ratio. Taking into account the structural evolution of the basin and accompanying salt tectonics, it is likely that the underlying Zechstein is a source for the less radiogenic fluids. Based on the samples in the LSB, it is probable that fibrous fracture fillings in sedimentary rocks most likely developed from locally derived pore fluids whereas elongate-blocky fracture fillings with smooth walls developed from externally derived pore fluids. [ABSTRACT FROM AUTHOR]

In order to obtain a proper knowledge base in primary care, a form of electronic patient record is needed that takes into account the specific characteristics of the doctor-patient encounter, the patient population, the presentation of diseases and the associated prevalences. However, in real life this has not happened for several reasons. For the most part, existing patient records are determined by invoicing requirements rather than by endeavours to meet the intrinsic needs of primary care. CONTENT (CONTinuous morbidity registration Epidemiologic NeTwork) is an ambitious scientific project in Germany to establish a system for adequate record keeping and analysis in primary care. Based on a classification system designed for the special situation of primary care, a scientific network is being established consisting of participating surgeries, general practitioners, computer scientists and statisticians. The project is supported by the German Federal Ministry of Education and Research. The aims are strictly scientific and the underlying hypothesis is that the knowledge-gaining process can be accelerated by combining the experience of many, especially with respect to complex interactions of factors and the analysis of rare events. Aside from maintaining a morbidity registry, within the CONTENT framework various prospective and retrospective studies on particular epidemiological and health economic research topics will be conducted. [ABSTRACT FROM AUTHOR]

Presents information on two methods which have been used in the measurement of chlorine leaving group kinetic isotope effect, for the SN2 reduction involving the benzyl chloride to toluene by sodium borohydride in dimethyl-sulphoxide (DMSO). Monitoring of reaction by titrating the unreacted borohydride ion; Information on these methods; Determination of the chlorine isotope effect.

Background: Platelets express several neutral glycosphingolipids with ABH and P blood group activity that may play a role in infectious, autoimmune, and alloimmune thrombocytopenia. In RBCs, sialylated glycosphingolipids or gangliosides with blood group activity have also been reported. To determine whether similar antigens are expressed by platelets, the total platelet ganglioside fraction was isolated and screened for blood-group-active glycosphingolipids.Study Design and Methods: Platelet gangliosides were isolated by organic extraction, base hydrolysis, anion exchange, silicic acid, and high-performance liquid chromatography. Gangliosides were identified and characterized by high-performance thin-layer chromatography-immunostaining with blood group-specific MoAbs and glycosidase digestion.Results: Group A, but not group O, platelets express five gangliosides with group A activity. Of five A MoAbs and lectins examined, only MoAbs Birma-1 and MHO4 recognized all five sialyl A bands. The sialyl A bands were sensitive to endoglycoceramidase and neuraminidase. One sialyl A band may represent a branched ganglioside with sialyl-I and group A activity. Platelets also express an LKE-active ganglioside consistent with sialyl-galactosylgloboside.Conclusion: In addition to sialyl-iI and sialyl-Le(x) gangliosides, group A platelets express gangliosides with LKE activity and group A activity. Like RBCs, group A-active gangliosides may act as alloantigens and autoantigens to naturally occurring isohemagglutinins. [ABSTRACT FROM AUTHOR]