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排序方式: 共有2175条查询结果,搜索用时 31 毫秒
1.
Cerebral microbleeds and cognitive decline in a hemodialysis patient: Case report and review of literature
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Lin Li Mark Fisher Wei‐Ling Lau Hamid Moradi Alexander Cheung Gaby Thai Jason Handwerker Kamyar Kalantar‐Zadeh 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(3):E1-E7
Cerebral microbleeds (CMBs) are small hemosiderin deposits indicative of prior cerebral microscopic hemorrhage and previously thought to be clinically silent. Recent population‐based cross‐sectional studies and prospective longitudinal cohort studies have revealed association between CMB and cognitive dysfunction. In the general population, CMBs are associated with age, hypertension, and cerebral amyloid angiopathy. In the chronic kidney disease (CKD) population, diminished estimated glomerular filtration rate has been found to be an independent risk factor for CMB, raising the possibility that a uremic milieu may predispose to microbleeds. In the end‐stage renal disease (ESRD) population on hemodialysis, the incidence of microbleeds is significantly higher compared with a control group without history of CKD or stroke. We present an ESRD patient on chronic hemodialysis with a history of gradual cognitive decline and progressive CMBs. Through this case and literature review, we illustrate the need to develop detection and prediction models to treat this frequent development in ESRD patients. 相似文献
2.
A Distributed Virtual Environment (DVE) system offers a computer-generated virtual world in which individuals located at different
places in the physical world can interact with one another. In order to achieve real-time response for a large user base,
DVE systems need to have a scalable architecture. In this paper, we present the design of a grid-enabled service oriented
framework for facilitating the construction of scalable DVE systems on computing grids. A service component called “gamelet”
is proposed, whose distinctive mark is its high mobility for supporting dynamic load sharing. We propose a gamelet migration
protocol which can ensure the transparency and efficiency of gamelet migration, and an adaptive gamelet load-balancing (AGLB)
algorithm for making gamelet redistribution decisions at runtime. The algorithm considers both the synchronization costs of
the DVE system and network latencies inherent in the grid nodes. The activities of the users and the heterogeneity of grid
resources are also considered in order to carry out load sharing more effectively. We evaluate the performance of the proposed
mechanisms through a multiplayer online game prototype implemented using the Globus toolkit. The results show that our approach
can achieve faster response times and higher throughputs than some existing approaches.
This research is supported in part by the China National Grid project (863 program) and the HKU Foundation Seed Grant 28506002. 相似文献
3.
The current Internet and wireless networks are harsh environments for transporting high-bandwidth multimedia data. We examine the technical issues involved, and describe an end-to-end solution to support a Web-based learn-on-demand system that operates in a wireless campus environment. 相似文献
4.
On the macroscopic optimization of multicell wireless systems with multiuser detection and multiple antennas - uplink analysis 总被引:1,自引:0,他引:1
In this paper, we consider a system with K single-antenna client users, n/sub B/ base stations (each base station has n/sub R/ antennas), as well as a centralized controller. A client user could be associated with a single base station at any time. All the base stations operate at the same frequency and have optimal multiuser detection per base station which cancels intracell interference only. We consider a general problem of uplink macroscopic resource management where the centralized controller dynamically determines an appropriate association mapping of the K users with respect to the n/sub B/ base stations over a macroscopic time scale. We propose a novel analytical framework for the above macroscopic scheduling problems. A simple rule is to associate a user with the strongest base station (camp-on-the-strongest-cell), and this has been widely employed in conventional cellular systems. However, based on the optimization framework, we found that this conventional approach is in fact not optimal when multiuser detection is employed at the base station. We show that the optimal macroscopic scheduling algorithm is of exponential complexity, and we propose a simple greedy algorithm as a feasible solution. 相似文献
5.
On the SEP of Cooperative Diversity with Opportunistic Relaying 总被引:1,自引:0,他引:1
We analyze the exact symbol error probability (SEP) of cooperative diversity with opportunistic amplify-and-forward (AF) relaying. The benefit of this opportunism to the SEP is assessed by comparing with maximal ratio combining of orthogonal multiple AF relay transmissions. 相似文献
6.
7.
A 78-year-old Chinese woman presented with recurrent postprandial abdominal pain. Computerised tomography revealed a small bowel tumour causing volvulus of a segment of the small bowel. Laparotomy confirmed an extraluminal ileal tumour with partial volvulus of the involved small bowel segment. Small bowel resection was done. Histological and ultrastructural studies confirmed a gastrointestinal autonomic nerve tumour. We review the medical literature on this rare tumour. 相似文献
8.
Pass-transistor adiabatic logic with NMOS pull-down configuration 总被引:13,自引:0,他引:13
A new low power adiabatic logic family, pass-transistor adiabatic logic with NMOS pull-down configuration, is presented. For a 2:1 multiplexer, a power saving of ~800% is achieved, compared to a 2N-2N2P logic circuit at 20 MHz. Compared to pass-transistor adiabatic logic using single power-clock supply (PAL), the `tri-state' problem is solved, while power consumption is comparable. A four phase sinusoidal clock power supply is employed in the new logic family, which facilitates pipelining hence leading to higher throughput, compared to PAL 相似文献
9.
BACKGROUND: The effect of angiotensin-converting enzyme (ACE) inhibitors in slowing the decline in renal function in nondiabetic renal disease varies among studies. PURPOSE: To use meta-analysis to assess the effect of ACE inhibitors on the development of end-stage renal disease caused by factors other than diabetes. DATA SOURCES: The English-language medical literature, identified by a MEDLINE search and unpublished studies. STUDY SELECTION: All randomized studies that compared ACE inhibitors with other antihypertensive agents and had at least 1 year of planned follow-up were selected. Studies of diabetic renal disease and renal transplants were excluded. A total of 1594 patients in 10 studies was included. DATA EXTRACTION: Data on end-stage renal disease, death, drop out, and blood pressure were extracted. Study investigators confirmed results and provided additional data. DATA SYNTHESIS: Among 806 patients receiving ACE inhibitors, 52 (6.4%) developed end-stage renal disease and 17 (2.1%) died; in the 788 controls, the respective values were 72 (9.1%) and 12 (1.5%). The pooled relative risks were 0.70 (95% CI, 0.51 to 0.97) for end-stage renal disease and 1.24 (CI, 0.55 to 2.83) for death; the studies were not significantly heterogeneous. The decreases in weighted mean systolic and diastolic blood pressures during follow-up were 4.9 and 1.2 mm Hg greater, respectively, in the patients who received ACE inhibitors. CONCLUSIONS: Angiotensin-converting enzyme inhibitors are more effective than other antihypertensive agents in reducing the development of end-stage nondiabetic renal disease, and they do not increase mortality. It could not be determined whether this beneficial effect is due to the greater decline in blood pressure or to other effects of ACE inhibition. 相似文献
10.
Investigation of optical losses in photoelastic and ridge waveguides in GaAs-AlGaAs heterostructures
Q.Z. Liu L.S. Yu S.S. Lau H.P. Zappe J.E. Epler 《Photonics Technology Letters, IEEE》1996,8(6):806-808
Two approaches have been used to fabricate stable photoelastic waveguides with planarized surfaces on GaAs-AlGaAs heterostructures. The first approach uses tensile Ni/sub 3/GaAs stressors formed by metal-semiconductor reactions. The second approach uses inert, refractory and compressive stressors, such as RF sputtered W and RF co-sputtered WNi films. For comparison purposes, ridge waveguides have also been fabricated using the same heterostructure by a dry etching technique. Optical losses of photoelastic waveguides, measured by Fabry-Perot (FP) method at a wavelength of 1.53 /spl mu/m, are comparable to or better than those of the ridge waveguides. Material loss appears to be the primary loss mechanism in both photoelastic and ridge waveguides. These results indicate that the photoelastic waveguide processing technique reported in this study is a promising alternative to commonly used dry etching techniques for planarization. 相似文献