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排序方式: 共有958条查询结果,搜索用时 15 毫秒
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IM Robbins EV Colvin TP Doyle WE Kemp JE Loyd WS McMahon GN Kay 《Canadian Metallurgical Quarterly》1998,98(17):1769-1775
BACKGROUND: This report describes the complication of pulmonary vein stenosis with resultant severe pulmonary hypertension that developed in 2 patients after successful catheter ablation of chronic atrial fibrillation. METHODS AND RESULTS: Three months after successful catheter ablation of atrial fibrillation, both patients developed progressive dyspnea and pulmonary hypertension. Both were found to have severe stenosis of all 4 pulmonary veins near the junction with the left atrium. Balloon dilation of the stenotic pulmonary veins was performed in these patients, with improvement in dyspnea and pulmonary hypertension. CONCLUSIONS: The complication of pulmonary vein stenosis is potentially life-threatening, and the application of radiofrequency current within the pulmonary veins with standard catheter technology should be avoided. This complication can be treated with balloon dilation, although the long-term course is unknown. 相似文献
43.
LR Barot JL Rombeau TP Stein R Chernoff RG Settle JL Mullen 《Canadian Metallurgical Quarterly》1982,6(1):34-38
To establish an animal model for the controlled study of enteral nutrition by tube, five adult chair-adapted primates (Macaca fasicularis) had gastrostomy and jejunostomy tubes placed for the delivery of a modified protein isolate diet. Following 7 days of postoperative depletion with a hypocaloric infusion of dextrose (20 kcal, 0 g N/kg/day), the animals were repleted for 10 days with tube feedings (124 kcal, 0.73 g N/kg/day). There was no operative mortality or morbidity and each animal demonstrated conversion to anabolism by significant weight gain, positive nitrogen balance, and net protein synthesis as determined by [15N]glycine protein turnover rates. Significant correlation was found between caloric intake and nitrogen balance at the level of nitrogen provided in this diet (r = 0.88, p less than 0.05). This model was found to be well suited for the surgical and nutritional techniques required for the long-term study of enteral nutrition by tube. 相似文献
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With the objective of clarifying the nature of renin-like activity in the brain, we have devised methods to distinguish true renin from acid protease. These methods were used to determine the regional distribution of true renin in hog brain. The pineal was found to be the richest source of renin followed by the adenohypophysis and choroid plexus. The hypothalamus, cerebellum and amygdala contained moderately high concentrations of renin. Renin concentration in the neurohypophysis was negligible. Many regions contained activatable prorenin. The molecular weight and the pH-dependence of the brain renin were identical to these same properties of renal and plasma renins. Based upon its specific affinity to concanavalin A, brain renin was judged to be a glycoprotein. The electrofocusing pattern of renin from different regions of the brain differed from that of plasma and kidney renins, a discrepancy which could be interpreted as evidence for the endogenous synthesis of renin in the brain. 相似文献
46.
Analytical isotachophoresis has been applied to the separation of urinary constituents in healthy controls and patients with rheumatoid and osteoarthritis. Various methods of comparing isotachograms have been investigated. Significant differences have been demonstrated between the pattern of UV-absorbing components in patients with rheumatoid arthritis and healthy subjects. 相似文献
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Weimin Wu Xin Li Gennady Gildenblat Glenn O. Workman Surya Veeraraghavan Colin C. McAndrew Ronald van Langevelde Geert D. J. Smit Andries J. Scholten Dirk B. M. Klaassen 《Electron Devices, IEEE Transactions on》2007,54(2):316-322
The valence-band electron (EVB) tunneling current in partially depleted silicon-on-insulator (SOI) MOSFETs increases as the gate oxide gets thinner and affects the dynamic behavior of devices and circuits. We present an engineering model of EVB tunneling current based on the surface-potential formulation. The new model is implemented in a SOI MOSFET compact model and is used to study the impact of EVB tunneling on circuit performance. Simulations of stacked logic gates show that the EVB tunneling current not only boosts circuit switching speed but also mitigates the history dependence of propagation delays 相似文献
49.
Nancy A. Skopp Don E. Workman Jamie L. Adler Gregory A. Gahm 《International journal of human-computer interaction》2013,29(12):901-910
Physical and temporal boundaries are rapidly diminishing in an age of swiftly advancing information communication technologies. Today’s technologically sophisticated business and organizational environments offer a number of distance collaboration modalities (DSMs) that can facilitate efficient and cost-effective meetings that have traditionally required face-to-face meeting venues. Selection of the DCMs that maximize meeting effectiveness is significantly challenging given the wide diversity of available options. Theory and empirical data can be useful as a guide in the selection of the most appropriate DCMs to maximize organizational productivity and success. This article reviews the literature on the behavioral and technical affordances and limitations of the various DCMs. It also provides a theoretical model based on media synchronicity theory to help guide selection of effective DCMs. This theoretical framework emphasizes the primacy of media alignment with core communication processes as well as social and interpersonal factors that influence meeting effectiveness. 相似文献
50.
J Slaninova SM Appleyard A Misicka AW Lipkowski RJ Knapp SJ Weber TP Davis HI Yamamura VJ Hruby 《Canadian Metallurgical Quarterly》1998,62(14):PL199-PL204
Mono iodinated analogues of biphalin [(Tyr-D-Ala-Gly-Phe-NH-)2], both nonradioactive [I-Tyr1]biphalin and radioactive [125I-Tyr1]biphalin have been synthesized. The radioligand binding profiles of these compounds for two types of tissues, rat brain membranes, and NG108-15 cell membranes were identical to the parent biphalin. This is additional evidence for the hypothesis that biphalin behaves like a monomeric ligand and that only one intact tyrosine is necessary for high biological activity. The second tyrosine could be used for successful radioiodination which may greatly simplify biochemical and pharmacological studies of biphalin. The results of receptor binding studies show that the binding of both biphalin and [I-Tyr1]biphalin to the delta and mu opioid receptors are not independent. [125I-Tyr1]Biphalin binds to delta receptors as shown in NG108-15 cell membranes. Nevertheless, [125I]biphalin binding to delta receptors in rat brain membranes was hardly evident and mu receptor binding predominated or at least was much more readily detectable in this preparation. 相似文献