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1.
Summary Reports on malodour in buildings constructed in the late 1970s gave rise to thorough investigations on the possible role of vapours of chemical compounds emitted by building materials. The odour could be related to the use of casein as an additive to improve the fluidity of concrete materials used as a self-levelling floor topping compound. Casein was suggested to be degraded by microorganisms, resulting in an accumulation of malodorous substances in the topping compounds.Bacteria isolated from biodeteriorated concrete materials containing caseins exhibited unusual tolerance towards high pH. Two dominant species were found among a total of 80 sporeforming, anaerobic isolates from concrete and raw products of caseins, namely Clostridium bifermentans and Clostridium sporogenes. C. bifermentans had a maximal pH tolerance of 12.2 while C. sporogenes could reproduce up to pH 11.7. The study includes the identification of the clostridia with API multitest as well as an investigation of the volatile organic acid and monoamine patterns. About 100 cfu clostridia/g material could be obtained during the isolation procedures.  相似文献   
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Mineral uptake by winter wheat (Trilicum aestivum L. cv. Martonvasari 8) was studied throughout the life cycle. Accumulation of macronutrients (i.e. total nitrogen, phosphorus, potassium, sodium, magnesium and calcium) and the water content of roots and shoots of plants grown in complete nutrient solution were higher than those of plants grown in two types of soils. The supply of macronutrients was in some cases limiting for soil-grown plants as revealed by a comparison of available and accumulated amounts of these nutrients. Their supply was abundant, however, for solution-grown plants. This led to a doubling of grain yield for the latter plants with a three fold increase in accumulation of dry matter and a five-fold increase in fresh weight. The efficiency ratios of solution-grown plants to soil-grown plants were approximately 1 for N and Na, 0.5 for Mg and Ca, and 0.3 for P and K.  相似文献   
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Zusammenfassung Die bei der sog. säurefesten Färbung im Spermienkopf enthaltene Kristallviolettmenge kann quantitativ mit cytophotometrischen Methoden bestimmt werden. Eine Fixierung mit abs. Alkohol und Färbung bei pH 7,5 ergab eine für quantitative Zwecke optimale Anfärbung. Die gebundene Kristallviolettmenge ist der DNS-Menge des Spermiums proportional. Es wird vermutet, daß die säurefeste Färbung auf einer Bindung des Kristallvioletts an die Phosphatgruppen der Nukleinsäuren beruht und daß die spezielle Anordnung der Nukleoproteine im Spermium eine wesentliche Rolle spielt.Mit Unterstützung der Deutschen Forschungs- Gemeinschaft.Stipendiat der Alexander v. Humboldt-Stiftung, 1962.  相似文献   
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Summary The pallid bat (Antrozous p. pallidus) uses passive sound localization to capture terrestrial prey. This study of captive pallid bats examined the roles of echolocation and passive sound localization in prey capture, and focused on their spectral requirements for accurate passive sound localization.Crickets were used as prey throughout these studies. All tests were conducted in dim, red light in an effort to preclude the use of vision. Hunting performance did not differ significantly in red light and total darkness, nor did it differ when visual contrast between the terrestrial prey and the substrate was varied, demonstrating that the bats did not use vision to locate prey.Our bats apparently used echolocation for general orientation, but not to locate prey. They did not increase their pulse emission rate prior to prey capture, suggesting that they were not actively scanning prey. Instead, they required prey-generated sounds for localization. The bats attended to the sound of walking crickets for localization, and also attacked small, inanimate objects dragged across the floor. Stationary and/or anesthetized crickets were ignored, as were crickets walking on substrates that greatly attenuated walking sounds. Cricket communication sounds were not used in prey localization; the bats never captured stationary, calling crickets.The accuracy of their passive sound localization was tested with an open-loop passive sound localization task that required them to land upon an anesthetized cricket tossed on the floor. The impact of a cricket produced a single 10–20 ms duration sound, yet with this information, the bats were able to land within 7.6 cm of the cricket from a maximum distance of 4.9 m. This performance suggests a sound localization accuracy of approximately ±1° in the horizontal and vertical dimensions of auditory space. The lower frequency limit for accurate sound localization was between 3–8 kHz. A physiological survey of frequency representation in the pallid bat inferior colliculus suggests that this lower frequency limit is around 5 kHz.  相似文献   
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The application of cellulose-based stationary phases for chiral separations has been extended to open tubular column chromatography. Efficient columns were obtained by coating the capillaries with mixtures of chiral cellulose materials and conventional achiral stationary phases for gas chromatography. In this study, various siloxane and polyethylene glycol polymers were used as achiral components and mixed with different substituted benzoylcellulose derivatives as chiral components. Systematic investigations were carried out to determine the optimal ratio for the components of the stationary phase. Depending on the chromatographic mode—gas chromatography (GC) or supercritical fluid chromatography (SFC)—the stationary phases were found to behave differently. The applicability of the technique was demonstrated by the resolution of various racemic compounds. © 1993 Wiley-Liss, Inc.  相似文献   
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Insoluble glycogen is an enzymatically modified form of naturally occurring soluble glycogen with a great adsorbing capacity. It can be metabolized by phagocytes to glucose. In this study we used insoluble glycogen intravenously in the experimental endotoxin shock of rats. Wistar male rats were sensitized to endotoxin by Pb acetate. The survival of rats were compared in groups of animals endotoxin shock treated and non-treated with insoluble glycogen. Furthermore, we have determined in vitro the binding capacity of insoluble glycogen for endotoxin, tumour necrosis factor alpha, interleukin-1 and secretable phospholipase A2. Use of 10 mg/kg dose of insoluble glycogen could completely prevent the lethality of shock induced by LD50 quantity of endotoxin in rats. All animals treated survived. Insoluble glycogen is a form of 'metabolizable internal adsorbents'. It can potentially be used for treatment of septic shock.  相似文献   
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The conducting pathway of the ferret's myocardium and endocardium was studied under the electron and scanning microscope. Comparisons between the two methods showed that the scanning microscope is well suited for those dimensional demonstration of biological material. Contrary to a relative absence of interspecific differences in endocardial morphology, there is a strong variation of this morphology related to the intracardiac localization of the endocardial cells. The following findings were obtained. S.e. microscopically, it was observed that the endocardium of the sino-atrial node region is not smooth, and that, more likely, it shows rough surfaced profiles. The electron microscopic study shows that the cells of the S-A node are elongated. The S-A node is located at the junction of the superior vena cava with the right atrial wall. It consists of nodal fibres which are embedded in a richinterstitial connective tissue (Figs 1-8). The Purkinje fibres originate from large bundles in the region of the right and left atrioventricular valve in the area where heart muscle fibres were originally described by Purkinje (Purkinje, 1845); these fibres, meanwhile, have become synonymous with cells of the generalized conducting system. The Purkinje fibres consist of a poorly developed contractile apparatus and contain unorganized, fine, filamentous material (Illustration 1). The SR is poorly developed, transverse tubules are absent. S.e. microscopically, one can visualize the trabecular system and the sinusoids. The trabeculae obtain muscle fibres rich in contractile material and transverse tubules. The trabeculae appear to be tendonous (chordae tendineae), especially when they freely traverse the ventricular cavity (Fig. 16). The interventricular septum (the muscle fibres from this region) takes its origin from large bundles in the region of the right and left atrioventricular valves. The endocardium of the interventricular septum is filled with large numbers of plasma-lemma folds (Figs 17, 18). The endocardium which covers the papillary muscle has a thickness of 0.5 micron. The endocardial cells lie on the myocardium so close and so thin that the surface relief and part of the atriation of the myocardium are visible (Figs 13-15).  相似文献   
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