Control of leg-powered paraplegic cycling using stimulation of the lumbo-sacral anterior spinal nerve roots

We investigated leg-powered cycling in a recumbent tricycle for a paraplegic using functional electrical stimulation (FES) with the lumbo-sacral anterior root stimulator implant (LARSI). A female complete T9 paraplegic had a stimulator for the anterior L2 to S2 spinal roots (bilaterally) implanted in 1994. She was provided with equipment for daily FES cycling exercise at home. The cycling controller applies a pattern of stimulation in each of 16 crank angle phases. A 7-bit shaft encoder measures the crank angle with adequate precision. Each pattern was originally chosen to give the greatest propulsive force in that position when there was no motion. However, dynamically, some reduction in co-contraction is needed; also the patterns are applied with a preset advance time. Maximal power is obtained with an advance of 250 ms, which compensates for muscle response delay and accommodates changes in cadence (from about 25 to 85 rpm). With this system, she has cycled 1.2 km at a time on gently undulating road. We found that spinal root stimulation gives sufficient control over the muscles in the legs to produce a fluid cycling gait. We propose that root stimulation for leg cycling exercise may be a practicable and valuable function for paraplegics following spinal cord injury.     

Five-year survival in persons aged 40 years or over with newly diagnosed diabetes mellitus

The five- to six-year all-cause mortality is analysed in 1323 newly diagnosed diabetic patients aged 40 years or over. The median age at diagnosis is lower for males (63.6 years) than for females (67.5 years), but more males (24.7%) than females (20.0%) have died (p = 0.04). This male excess mortality can mainly be attributed to the 60-79-year old males. With increasing diabetes duration both male and female diabetic patients exhibit an increasing excess mortality in comparison with the Danish population. For males this excess mortality becomes statistically significant four years after diagnosis for the 40-59 year-olds and after six years for the 60-79 year-olds. For females and very old males no statistically significant excess mortality is observed, but after two to four years there is a tendency for the survival curve of 40-79-year old females to separate from that of the Danish female population to show an excess mortality. In this population-based study the disadvantageous mortality experience of even newly-diagnosed diabetic patients is clearly demonstrated.     

Visualization and debugging of distributed multiagent systems

Visualizing the behavior of systems with distributed data, control, and process is a notoriously difficult task. Each component in the distributed system has only a local view of the whole setup, and the onus is on the user to integrate, into a coherent whole, the large amounts of limited information they provide. In this article, we describe an architecture and an implemented system for visualizing and controlling distributed multiagent applications. The system comprises a suite of tools, with each tool providing a different perspective of the application being visualized . Each tool interrogates the components of the distributed application, collates the returned information, and presents this information to users in an appropriate manner. This in essence, shifts the burden ofinference from the user to the visualizer. Our visualizer has been evaluated on four distributed multiagent systems: a travel management application, a telecommunications network management application, a business process management demonstrator, and an electronic commerce application. Lastly, we briefly show how the suite of tools can be used together for debugging multiagent applications - a process we refer to as debugging via corroboration.     

Loss reduction in InGaAs/InGaAlAs quantum well electron transferwaveguides using ion implantation

We demonstrate that phosphorous ion implantation is an effective means of blue-shifting the absorption edge in InGaAs/InGaAlAs barrier, reservoir and quantum well electron transfer structures (BRAQWETS). The electroabsorption peak is wavelength-shifted by 100 nm after implant, with a complete recovery of the electroabsorption magnitude after an appropriate rapid thermal anneal cycle. Good electrical characteristics are also maintained after implant and anneal. We apply this technique to loss reduction for BRAQWETS waveguide devices. At 1.523 mm, the implant and anneal results in a decrease of rib waveguide propagation loss from 79.4 dB/mm to 6.2 dB/mm     

More on the limits-to-growth controversy.

Comments on P. C. Stern's (1978) article on the professional notice psychologists and other social scientists are taking of the limits-to-growth controversy, concerning solutions to environmental and resource problems. The ongoing debate is examined between those who believe in the necessity of limits and those who believe in the maximizing of personal freedom. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Re: Proportionate mortality among union members employed at three Texas refineries

OBJECTIVES:We established an in vitro model to investigate the effects of valve sizing on the hemodynamic characteristics and leaflet motion of the Toronto SPV valve (St Jude Medical, Inc, St Paul, Minn). METHODS: Nine valves were first implanted in fresh porcine aortic roots and then retested in glutaraldehyde-treated porcine aortic roots. Three valves were 1- to 2-mm oversized, 3 were 1- to 2-mm undersized, and there were 3 size-for-size implantations. The elasticities of the aortic roots and the composite roots were measured in the pressure range between 0 and 120 mm Hg, and the composite roots were then tested in a pulsatile flow simulator. The transvalvular gradient and regurgitation were measured and the effective orifice area and performance index were calculated for each root. Leaflet motion was recorded on videotape. RESULTS: The external diameter of the fresh root increased by 35% as the hydrostatic pressure rose from 0 to 120 mm Hg, as compared with 11% for the glutaraldehyde-treated root. Valve implantation in the fresh root reduced the distensibility to 22% but did not change distensibility in the glutaraldehyde-treated root. The effective orifice area was dependent on the valve size, with the transvalvular gradient decreasing as the valve size increased. For the same size of valve the hydrodynamic parameters were slightly better if the valve was undersized by 1 mm. A significant difference in favor of the undersized valves was found in open-leaflet bending deformation. CONCLUSION: Leaflet motion of the stentless porcine aortic valve in vitro is improved if the valve is slightly undersized, and this may be beneficial to the long-term durability of the prosthesis.     

Electrochemical characteristics of porous TiO2 encapsulated silicon anode

TiO₂ coated silicon, which was prepared by the modified sol–gel method, was employed as the anode material for lithium secondary batteries and the relationship between the diffusivity and electrochemical characteristics was investigated. The results showed that the physical properties of the samples, such as their diffusivity and pore size distribution, enhanced the cycling efficiency of the TiO₂ coated silicon, probably due to the reduction of the side reactions, which may be closely related to the pore size distribution of the TiO₂ coating layer. The pore size of the coating layer plays an important role in retarding the lithium ion diffusion. In the experimental range studied herein, higher capacity retention was exhibited for the TiO₂ coated silicon prepared at pH 10.7.     

Minnesota Multiphasic Personality Inventory (MMPI) cluster groups among chronically ill patients: relationship to illness adjustment and treatment outcome

Cluster analysis of the MMPI has been utilized widely in the chronic low back pain literature to try to identify reliable patient subtypes predictive of treatment outcome. We extended this methodology to patients with heterogeneous chronic medical conditions by replicating prototypic MMPI cluster group profiles and by relating cluster groups to clinical baseline and outcome data. Subjects were two independent samples (n = 254 and n = 263) of chronically ill patients admitted to an inpatient medicine/psychiatry unit. Using a four-cluster solution, similar cluster profile groups were replicated in both samples. Consistent differences emerged between cluster groups on functional impairment, psychiatric diagnoses, depression, and psychosomatic symptoms. Cluster group membership also predicted changes in functional impairment and depression six months after treatment. Results are discussed in terms of similarities between chronic low back pain and chronic illness and tailoring treatment to different patient types.