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461.
Retroperitoneal and mediastinal emphysema as a complication of colonoscopy, though infrequent, may occur. It is important to realize that this can be a benign clinical condition that will resolve with conservative management. A case of retroperitoneal emphysema after routine colonoscopy is reported with a review of literature and a brief discussion.  相似文献   
462.
463.
A computer-assisted continuous infusion (CACI) system which would rapidly attain and maintain a constant plasma level (i.e., constant set point) of the opiod, fentanyl, was designed. This open-loop CACI system was then modified to allow the anesthesiologist (clinician) to adjust the plasma level (set point) intraoperatively (i. e., a variable set point); however, since no sensor is presently available to measure the plasma concentration of fentanyl on line, a mathematical model was implemented to simulate the plasma fentanyl concentration (PFC). This interactive system was tested in 20 patients undergoing coronary artery bypass grafting surgery. The measured PFC/CACI predicted PFC was determined to be 1.04 ±0.25 (mean ±S.D.) for the 170 samples analyzed. A correlation coefficient of 0.90 (p < 0.0001) was found between the measured PFC and the CACI system model prediction. These data indicate that the CACI system is an easy way to provide predictable constant plasma fentanyl levels during the precardiopulmonary bypass period of cardiac surgery.  相似文献   
464.
465.
In an earlier study, we reported that hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) biodegraded with domestic anaerobic sludge to produce a key RDX ring cleavage intermediate that was tentatively identified as methylenedinitramine (O2NNHCH2NHNO2) using LC/MS with negative electrospray ionization (ES-). Recently, we obtained a standard material of methylenedinitramine and thus were able to confirm its formation as the key initial RDX intermediate. In water alone or in the presence of sludge, methylenedinitramine decomposed to N20 and HCHO. Only in the presence of sludge HCHO converted further to carbon dioxide. To test our hypothesis that water was involved in the formation of methylenedinitramine during incubation of RDX with sludge, we allowed the energetic compound to biodegrade in several D2O/H2O solutions (90, 50, and 0% v/v). We observed three distinctive deprotonated or dedeuterated mass ions at 135, 136, and 137 Da that were attributed to the formation of nondeuterated (H-methylenedinitramine), monodeuterated (D1-methylenedinitramine), and dideuterated methylenedinitramine (D2-methylenedinitramine), respectively. Two controls were prepared in D2O both in the absence of sludge; the first contained methylenedinitramine, and the second contained RDX. Neither control produced any deuterated methylenedinitramine, thus excluding the occurrence of any abiotic D/H exchange between D2O and either methylenedinitramine or RDX. The results supported the occurrence of an initial enzymatic reaction on RDX, yet they did not provide compelling evidence on whether methylenedinitramine was an initial RDX enzymatic hydrolysis product or simply formed via the spontaneous hydrolysis of an anonymous initial RDX enzymatic product.  相似文献   
466.
这个花园譬喻我们生活的地球。一串小岛在循环流动的水面上展开,每个小岛上生长着各种各样的植物。一条木径跨过池塘,池塘的中心设有一处空间,让人们可在此思考和观察日益面临威胁的生物多样性的神秘之处。游园者还可以踩踩动力脚踏,  相似文献   
467.
We investigated a link between hemoglobin primary structure, hemoglobin hydrophobicity-hydrophilicity, and erythrocyte water content in various mammalian species. Some hemoglobin molecules, particularly those of the camel and camelids, contain more charged amino acid residues and are more hydrophilic than the hemoglobins of human and a number of other mammalian species. To test the in vivo significance of these alterations of hemoglobin primary structure, we determined the osmotically unresponsive erythrocyte water fractions in mannit solutions of various osmolarities at 4 degreesC. Among the species investigated, the size of the osmotically unresponsive erythrocyte water fraction relates in a positive linear way to hemoglobin hydrophilicity. The extreme low total erythrocyte water content of camel erythrocytes (1.1-1.3 g water/g dry mass) may be explained by a comparatively high osmotically unresponsive erythrocyte water fraction. It is proposed that alterations of hemoglobin sequences of camel and camelids may be the part of a natural selection process aimed at protecting these animals against osmotic dehydration in arid environments.  相似文献   
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