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排序方式: 共有437条查询结果,搜索用时 15 毫秒
1.
A Serrano Pascual C Merino Hernáez R Ochoa Mejías A Escolano Chamois J Golbano Ablanque I Otero Tejero M Sanz Redondo F Román Ruiz 《Canadian Metallurgical Quarterly》1997,21(6):631-635
BACKGROUND AND AIMS OF THE STUDY: Surgical treatment of functional tricuspid regurgitation associated with advanced valvular disease remains controversial, mainly due to the difficulty in choosing between valve replacement or reconstructive surgery. Failure to correct tricuspid regurgitation during valvular surgery carries a poor prognosis, as reoperation may represent a significant risk to the patient. Thus correct tricuspid valve surgery is vital to achieve improved early and long-term clinical results. METHODS: A total of 142 patients underwent concomitant tricuspid annuloplasty with mitral valve replacement and their clinical outcome was assessed. RESULTS: Overall hospital mortality rate was 11.3%. Seven patients died during follow up. The overall actuarial survival rate for 10 years was 74.1 +/- 14.2%. Postoperatively, 75.8% of the patients had no residual tricuspid insufficiency, while 24.2% had first- or second-degree tricuspid insufficiency and were treated medically. All patients were in NHYA functional class I or II postoperatively. CONCLUSION: Clinically, it is important to assess the severity of functional tricuspid insufficiency before and/or during the operation. Bicuspidalization annuloplasty for functional tricuspid insufficiency has provided good results, with a low incidence of reoperation and significant clinical improvement. The technique could be used in most patients with functional tricuspid regurgitation. 相似文献
2.
1 放射性废物管理方面( 1 )应当建立一个国家级的废放射源管理战略。此战略应包括过去、现在和将来产生的所有放射性废物。此废物管理战略可以由国家指定的委员会来制订。该委员会可以包括来自主要废物的产生单位、废物管理机构和相应的审管部门的代表。此战略应当涵盖技术选择 (处理和处置 )和基础架构 (废物管理机构和基金 )。( 2 )放射性废物管理 ,包括废密封源管理。要求有专门的技术设施和特别训练的人员。为避免基础结构和人力资源重复设置 ,可以考虑单一的废物管理机构。该机构可设有区域性的分支机构 ,也可以设有专门的部门管理来… 相似文献
3.
The therapeutic panorama of immunomodulation and its effects on the modification of the immune reaction is reviewed. Particular reference is made to the transfer factor as a therapeutic element in bronchial asthma, which insures its efficacy or innocuity. 相似文献
4.
Bernhard Blümich Vladimir Anferov Sophia Anferova Martin Klein Radu Fechete 《大分子材料与工程》2003,288(4):312-317
A special unilateral NMR sensor has been designed for investigations of thin samples with a thickness of less than 1 mm and of surface effects of polymers. For use with the bar‐magnet NMR‐MOUSE®, the so‐called “crazy coil” is introduced with a low penetration depth. It is a flat meander coil etched on a printed circuit board with wiggles in the conductors. The design of the new coil and FEM simulations of the B 1 field are presented. Different applications are discussed by means of illustrative examples. They are the detection of surface damage in rubber samples, the swelling and drying of a latex membrane exposed to cyclohexane vapor mimicking a chemical sensor, and the drying of a thin sprayed adhesive layer.
5.
We demonstrate a microfluidic continuous-flow protein separation process in which silica-coated superparamagnetic nanoparticles
interact preferentially with hemoglobin in a mixture with bovine serum albumin, and the resulting hemoglobin-nanoparticle
aggregates are recovered online using magnetophoresis. We present detailed modeling and analysis of this process yielding
quantitative estimates of the recovery of both proteins, validated by experiments. While several previous studies utilize
an average particle size in modeling magnetophoretic particle trajectories or process design, in this study we emphasize the
importance of accounting for particle size distributions in calculating particle recovery, and therefore in estimating separation
efficiency. We combine experimentally measured size distributions of protein-nanoparticle aggregates with simulations of particle
trajectories and provide a simple analytical method to calculate the efficiency of separation at various flow speeds, which
fully accounts for heterogeneity in particle sizes. Our method can potentially be used for affinity based biomolecular separations
at both analytical and preparative scales by exploiting well-established techniques to functionalize nanoparticle surfaces
with selective ligands. Further, the modeling methodology presented here may be applied to provide better estimates of particle
recovery in a broad range of magnetophoretic separation processes involving heterogeneity in particle sizes. 相似文献
6.
Reliability and time‐to‐failure bounds for discrete‐time constrained Markov jump linear systems 下载免费PDF全文
This paper presents a methodology to obtain a guaranteed‐reliability controller for constrained linear systems, which switch between different modes according to a Markov chain (Markov jump linear systems). Inside the classical maximal robust controllable set, there is 100% guarantee of never violating constraints at future time. However, outside such set, some sequences might make hitting constraints unavoidable for some disturbance realisations. A guaranteed‐reliability controller based on a greedy heuristic approach was proposed in an earlier work for disturbance‐free, robustly stabilisable Markov jump linear systems. Here, extensions are presented by, first, considering bounded disturbances and, second, presenting an iterative algorithm based on dynamic programming. In non‐stabilisable systems, reliability is zero; therefore, prior results cannot be applied; in this case, optimisation of a mean‐time‐to‐failure bound is proposed, via minor algorithm modifications. Optimality can be proved in the disturbance‐free, finitely generated case. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
7.
The study aims were, in a population of university students, staff, and faculty (n = 140), to: 1) determine the distribution of seven measures of mobile device use; 2) determine the distribution of musculoskeletal symptoms of the upper extremity, upper back and neck; and 3) assess the relationship between device use and symptoms. 137 of 140 participants (98%) reported using a mobile device. Most participants (84%) reported pain in at least one body part. Right hand pain was most common at the base of the thumb. Significant associations found included time spent internet browsing and pain in the base of the right thumb (odds ratio 2.21, 95% confidence interval 1.02–4.78), and total time spent using a mobile device and pain in the right shoulder (2.55, 1.25–5.21) and neck (2.72, 1.24–5.96). Although this research is preliminary, the observed associations, together with the rising use of these devices, raise concern for heavy users. 相似文献
8.
9.
ATP-regulation of antioxidant properties and phenolics in litchi fruit during browning and pathogen infection process 总被引:3,自引:0,他引:3
Chun Yi Yueming Jiang John Shi Hongxia Qu Sophia Xue Xuewu Duan Jingyu Shi Nagendra K. Prasad 《Food chemistry》2010
The impact of energy level on antioxidant properties in relation to pericarp browning and loss of disease resistance of litchi fruit was investigated. Litchi fruits were vacuum-infiltrated with distiled water (control), 1 mM adenosine triphosphate (ATP) and 0.5 mM 2,4-dinitrophenol (DNP) under 75 kPa for 3 min before being inoculated with Peronophythora litchi or not. ATP-treated fruits presented higher activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX). Higher activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, reducing power and contents of phenolic compounds were also observed in ATP-treated fruit during storage. In contrast, DNP treatment lowered the enzymes activities, scavenging ability and the contents of phenolic compounds. Higher levels of antioxidant enzymatic system and non-enzymatic system were observed in P. litchii-inoculated fruits than those in non-inoculated fruits. Application of ATP and DNP exhibited a similar change patterns and effects in inoculated fruits. When related to previously reported ATP levels, the results suggested that ATP levels could regulate the antioxidant system. Sufficient available energy is crucial for inhibiting browning and preventing the loss of disease resistance in harvested litchi fruit. 相似文献
10.
王刘坤 Twan Bear Karine Kenis Sophia Arnauts Patrick Van Doorne 陈寿面 Paul Mertens Marc Heyns 《半导体学报》2004,25(5):502-507
采用可控的金属沾污程序 ,最大金属表面浓度控制在 10 1 2 cm- 2数量级 ,来模拟清洗工艺最大可能金属沾污表面浓度 .利用斜坡电流应力和栅注入方式测量本征电荷击穿来评估超薄栅氧特性和金属沾污效应 .研究了金属锆和钽沾污对超薄栅氧完整性的影响 .实验结果表明金属锆沾污对超薄栅氧完整性具有最严重危害 ;金属钽沾污的栅氧发生早期击穿现象 ,而金属铝沾污对超薄栅氧完整性没有明显影响 . 相似文献