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991.
Changes in activity of enzymes involved in energy metabolism have been determined in unfused, fused as well as in fusion-inhibited chick embryo muscle cells in vitro. Functionally related enzymes which supposedly are coded by "gene clusters" show a similar degree and rate of enzyme activity increase. Hexokinase and glucose-6-phosphate dehydrogenase reveal only slight activity changes during muscle cell development under the conditions studied. The elevation of phosphofructokinase can be distinguished from that of the other glycolytic enzymes by its higher rate of increase and from that of phosphorylase by its time-course of activity change. The Ca2+ dependence of the phosphorylase activity increase runs parallel to myoblast fusion rate. Experiments in which calcium was removed from cultures which had reached the final morphological state of mature myotubes 24 h after onset of fusion show that increases of enzyme activities are irreversible and that these increases proceed at unchanged rates. Experimental evidence suggest that although fusion and enzyme syntheses may be uncoupled, both are similarly triggered by being dependent on Ca2+ concentration. 相似文献
992.
J Dobroschke K Schwemmle P Hermanek W R?sch 《Canadian Metallurgical Quarterly》1976,101(39):1409-1412
From 1961 to 1975, 53 patients were operated on for early carcinoma of the stomach, 24 of the total of 57 cancer sites being limited to the mucosa, 33 having already infiltrated into the submucosa. Macroscopically, most of them were ulcerative carcinoma, while histologically the intestinal type predominated. The cumulative five-year survival rate (excluding hospital deaths) was 86.5%, while after "typical" carcinoma resection by the Billroth II procedure with removal of the greater and lesser omentum it was 100% for mucosal and 93% for submucosal carcinoma. 相似文献
993.
LG Kupchinski? IuA Barshte?n BG Pogodaev AI Treshinski? 《Canadian Metallurgical Quarterly》1976,(3):80-84
A study was made of a possibility of using Soviet made membranes "Vladipor" with a pore diameter of 16--17 nm for the purpose of concentration and purification of antigenic extracts from stab cultures of S. typhi obtained by the action of typsin, hydrogen peroxide and detergents. Preparations, complete by antigenic structure, were obtained by ultrafiltration, with a good yield. The maximal rate of ultrafiltration was noted in case of "peroxide" antigenic preparations. The use of diafiltration provided a significant reduction of the ash content in the end products. 相似文献
994.
F Markwardt HP Kl?cking K Sedlarik J Perlewitz J Drawert J Hoffmann 《Canadian Metallurgical Quarterly》1976,35(2):193-203
The purpose of this investigation was to explore the feasibility of enhancing the electrochemical stability of dental amalgam restorations by a process of "selective interfacial amalgamation." If dental amalgam restorations can be selectively alloyed at the tooth-amalgam interface, to a minor thickness as compared with the dimensions of the bulk amalgam, so as to present a more electrochemically stable phase than psi2 to the oral environment, corrosion will be reduced and desirable qualities of existing amalgams can be utilized. It was found that selective interfacial amalgamation was indeed possible and that it could be readily accomplished using a silver suspension as a cavity liner. By then placing a conventional silver-tin amalgam according to ordinary dental techniques, mercury expressed during hand condensing reacted with the silver in the liner resulting in the formation of an integral amalgam restoration with the more noble psi1 phase adjacent to tooth structure. In vitro corrosion tests of samples so prepared exhibited corrosion resistance far superior to unlined control samples. 相似文献
995.
I Sj?gren 《Canadian Metallurgical Quarterly》1976,57(5):208-222
Tuberculosis causing exemption from military service was studied in 47,791 tuberculin-tested military recruits between 1941 and 1946. A total of 46.6% were tuberculin negative, and two-thirds were BCG vaccinated. An analysis was made of 304 cases of tuberculosis discovered from 6 months after the test up to the end of 1960. It has been calculated that 69% of "expected cases" of tuberculosis were in the BCG-vaccinated men during the 5-year period after the test, and 20% during the following period; 46% of "expected cases" of post-primary pulmonary tuberculosis and 83% of "expected" deaths were prevented. The differences on which these percentages are based were statistically significant. The efficacy of BCG vaccination was lower in areas with widespread cattle tuberculosis than in areas where cattle tuberculosis is less frequent; this is explained by the influence of previously acquired immunity. 相似文献
996.
The authors' experience with 45 papillosphincterotomies, performed for diseases of bile passages and chronic pancreatitis, is reported. The details of the operative technic, employed by the authors, are described. The technic of papillosphincterotomy on a conus-shape sound by means of a "laser scalpel" proved to be the most perfect one. Careful observation of the surgical technic made it possible to gain favourable results--only 1 of 45 operated patients died. Papillosphincterotomy is largely advocated in stenoses and concretions in the large duodenal papilla, strictures of choledocho-duodenoanastomoses, care should be taken not to overwiden indications to the operation concerned. 相似文献
997.
Histories of deliveries and development records of 44 newborns with penumopathies who had died on the first days of life in the presence of phenomena of the syndrome of respiratory disorder were analysed and the newborns' lungs were morphologically investigated. The investigation made it possible to single out the following forms of pneumopathy in newborns: edematous-hemorrhagic, hyaline, atelectatic, aspirated, and mixed. In the majority of cases the syndrome of respiratory disorder was a sequela of hypoxia of the intrauterine origin which continued during the first hours and days of life after birth. Such "primary asphyxia" may lead to the development of pneumopathy in a neonate. On the other hand, "secondary asphyxia" in many cases represent sequelae of penumopathy destructural and functional immaturity of the pulmonary tissue, hypoxia, a higher permeability of vessels of the microcirculatory bed, spasm of small pulmonary arteris contributed considerably to the development of penumopathies. 相似文献
998.
The field of systems biology has attracted the attention of biologists, engineers, mathematicians, physicists, chemists and others in an endeavour to create systems-level understanding of complex biological networks. In particular, systems engineering methods are finding unique opportunities in characterizing the rich behaviour exhibited by biological systems. In the same manner, these new classes of biological problems are motivating novel developments in theoretical systems approaches. Hence, the interface between systems and biology is of mutual benefit to both disciplines. 相似文献
999.
In list-method directed forgetting, participants are cued to intentionally forget a previously studied list while remembering a subsequently presented 2nd list. Results from prior research are inconclusive on whether older adults show deficits in this type of task. In 3 experiments, the authors reexamined the issue and compared younger and older adults' responsiveness to the forget cue. Across the experiments, the forget cue was varied within and between participants, the 2 lists were unrelated and related to each other, and recall of the lists was required simultaneously and successively. In none of the 3 experiments did any age-related difference in directed forgetting performance emerge. List-method directed forgetting is assumed to reflect retrieval inhibition. The present results thus challenge the proposal of a general inhibitory deficit in older adults' memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
1000.
The assumption that people possess a strategy repertoire for inferences has been raised repeatedly. The strategy selection learning theory specifies how people select strategies from this repertoire. The theory assumes that individuals select strategies proportional to their subjective expectations of how well the strategies solve particular problems; such expectations are assumed to be updated by reinforcement learning. The theory is compared with an adaptive network model that assumes people make inferences by integrating information according to a connectionist network. The network's weights are modified by error correction learning. The theories were tested against each other in 2 experimental studies. Study 1 showed that people substantially improved their inferences through feedback, which was appropriately predicted by the strategy selection learning theory. Study 2 examined a dynamic environment in which the strategies' performances changed. In this situation a quick adaptation to the new situation was not observed; rather, individuals got stuck on the strategy they had successfully applied previously. This "inertia effect" was most strongly predicted by the strategy selection learning theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献