A three-year follow-up on standard versus thin wall ePTFE grafts for hemodialysis

PURPOSE: Expanded polytetraflouroethylene (ePTFE) grafts are the most popular prosthetic grafts for hemodialysis patients in whom autogenous fistulas cannot be constructed. Long-term studies to study the durability and complication rate of the different wall configurations of ePTFE grafts have not been carried out. The primary, secondary, and cumulative patency and other complications between standard thickness (STD) and thin wall (THN) 6 mm stretch ePTFE grafts (WL Gore & Assoc, Flagstaff, AZ) was prospectively evaluated. METHODS: From September 1993 to August 1995, 108 patients receiving new grafts were randomized into 2 groups: those receiving STD grafts (n = 56) or those receiving THN (n = 52) grafts. Data prospectively collected included day of first access, primary patency, interventions required, and long-term results. Infections, pseudoaneurysms, and mortality were also documented. Student's unpaired t-test was used to compare the 2 groups, and log-rank life tables were constructed and compared. RESULTS: Mean follow-up examination time was 38.1 +/- 0.8 months for STD grafts and 35.1 +/- 1.0 months for THN grafts (P<.03). Longer patency was noted in the STD group of grafts (18.2 months for STD vs. 12.1 months for THN). Biographical data and complications, including pseudoaneurysm (6% vs. 5%), infection (2% vs. 3%), and mortality (22% vs. 19%), between STD and THN groups were not different statistically. Mean primary (18.2 months vs. 12.1 months), secondary (20.9 months vs. 13.7 months), and cumulative patency times (22.2 months vs. 15.2 months) for the STD group were significantly more than those for the THN group (P<.000 by log rank of life tables). Other complications were not different between groups. CONCLUSION: Standard thickness ePTFE is the graft of choice when placing ePTFE arteriovenous grafts for hemodialysis.     

Computer brainstorms: More heads are better than one.

Research has consistently found nominal group brainstorming (in which members work separately without communicating) to be superior to brainstorming in which group members interact verbally. This article presents the results of an experiment that found the reverse to be true for computer-mediated electronic brainstorming. In this experiment, 12-member electronically interacting groups generated more ideas than did 12-member nominal groups, and there were no differences between 6-member electronic and 6-member nominal groups. The authors attribute these results to the ability of electronic brainstorming to introduce few process losses (production blocking, evaluation apprehension, and free riding) while enabling process gains (synergy and the avoidance of redundant ideas). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electric Field Measurements inside Self-Assembled Multilayer Films at Electrode Surfaces by Electrochemically Modulated Surface Plasmon Resonance Experiments

The new in situ optical technique of electrochemically modulated surface plasmon resonance (EM-SPR) is described and applied to the measurement of the electrostatic fields inside noncentrosymmetric zirconium phosphonate (ZP) films formed from the asymmetric nonlinear optical material [1-[4-[4-[(N-(2-hydroxyethyl)-N-methyl)amino]phenyl]azo](5-phosphonopentyl)] pyridinium bromide (PY-AZO). In situ EM-SPR measurements on PY-AZO films yield a value for the change in electric field strength (ΔE) of 4 × 10³ V/cm for a change in electrode potential (Δϕ_m) at 0.0 V vs. SCE of ±25 mV (8 × 10⁴ V/cm for Δϕ_m = 1 V). This electric field strength value indicates that there is substantial ion penetration into the film in the electrochemical environment. Both the phase and magnitude of the surface optical response in the EM-SPR measurements are used to distinguish the molecular and metal electrode contributions to the overall optical signal. These two EM-SPR contributions are identified and separated in a quantitative fashion through a series of theoretical Fresnel calculations.     

Explicit construction of quadratic lyapunov functions for the small gain,positivity, circle,and popov theorems and their application to robust stability. part II: Discrete-time theory

In a companion paper (‘Explicit construction of quadratic Lyapunov functions for the small gain, positivity, circle, and Popov theorems and their application to robust stability. Part I: Continuous-time theory’), Lyapunov functions were constructed in a unified framework to prove sufficiency in the small gain, positivity, circle, and Popov theorems. In this Part II, analogous results are developed for the discrete-time case. As in the continuous-time case, each result is based upon a suitable Riccati-like matrix equation that is used to explicitly construct a Lyapunov function that guarantees asymptotic stability of the feedback interconnection of a linear time-invariant system and a memoryless nonlinearity. Multivariable versions of the discrete-time circle and Popov criteria are obtained as extensions of known results. Each result is specialized to the linear uncertainty case and connections with robust stability for state-space systems is explored.     

The journal list and its use: motivation,perceptions, and reality

The Bauer College of Business at the University of Houston uses lists of journals as part of its process to evaluate and reward the research productivity of its faculty. The creation of the journal lists was proposed for three reasons: to target faculty research as to which journal outlets the College deemed acceptable, to encourage cross-disciplinary research, and to decrease the internal politicizing of the journals themselves. This article discusses the history and use of the lists as well as surveying faculty perceptions. The use of the journal list is imperfect. Faculty seem unclear as to the use of the lists and there does not seem to have been a substantial increase in cross-discipline research. While the tenor of the discussions about the merits of a journal has changed, interdepartmental politicizing of journals continues. Consistency of annual reviews, however, has increased substantially.     

提高数据中心系统的配电效率

提高配电电压可以显著提高供电效率并降低成本 大多数现代信息技术装备的设计都考虑到全球兼容性.这些设备不仅可以运行于北美的120/208V、日本的100/200V配电系统下,也可以运行于世界其他地方采用的230V配电系统.如果世界其他地方采用的配电系统被北美数据中心采用,那么将能够提高效率、降低成本,减少地面负重、节约占地空间,并简化电力电缆架设.     

Nominees as Candidates for the Executive Board 1989–1991

ABSTRACT

Principles of sustainable development are inviting a change in the approach used for reservoir management. Instead of designing and planning new reservoirs, more emphasis will be placed on management of existing reservoirs. Reservoir storage reallocation and reassessment of reservoir operational rules are considered to be the two main problems to be addressed by reservoir research in the near future. Appropriate techniques for solving these two problems are necessary An attempt at developing a sound methodology for a reservoir reassessment has been presented here. A simulation approach, based on the four probability criteria, has been used in this context for storage analysis. Reservoir management strategies have been reassessed using an implicit stochastic optimization model. The methodology has been applied to Wonogiri Reservoir located in Central Java, Indonesia. Analysis of the storage capacity indicated that the current capacity is larger than that required for the irrigation of an area of 25,319 ha, corresponding to the Wonogiri reservoir final development phase. Thus, the present size of the reservoir allows for additional multipurpose use of the reservoir storage. Optimization of the reservoir yield demonstrated that the reservoir can provide for municipal and industrial water supply and hydropower generation in addition to the current use af reservoir storage for irrigation water supply.     

3,5‐Bis(benzylidene)‐4‐oxo‐1‐phosphonopiperidines and Related Diethyl Esters: Potent Cytotoxins with Multi‐Drug‐Resistance Reverting Properties

A series of 3,5‐bis(benzylidene)‐4‐piperidones 3 were converted into the corresponding 3,5‐bis(benzylidene)‐1‐phosphono‐4‐piperidones 5 via diethyl esters 4 . The analogues in series 4 and 5 displayed marked growth inhibitory properties toward human Molt 4/C8 and CEM T‐lymphocytes as well as murine leukemia L1210 cells. In general, the N‐phosphono compounds 5 , which are more hydrophilic than the analogues in series 3 and 4 , were the most potent cluster of cytotoxins, and, in particular, 3,5‐bis‐(2‐nitrobenzylidene)‐1‐phosphono‐4‐piperidone 5 g had an average IC₅₀ value of 34 nM toward the two T‐lymphocyte cell lines. Four of the compounds displayed potent cytotoxicity toward a panel of nearly 60 human tumor cell lines, and nanomolar IC₅₀ values were observed in a number of cases. The mode of action of 5 g includes the induction of apoptosis and inhibition of cellular respiration. Most of the members of series 4 as well as several analogues in series 5 are potent multi‐drug resistance (MDR) reverting compounds. Various correlations were noted between certain molecular features of series 4 and 5 and cytotoxic properties, affording some guidelines in expanding this study.