A novel electrochemical anodization cell for the synthesis of mesoporous silicon.

A novel design of an electrochemical anodization cell dedicated to the synthesis of mesoporous, single-crystalline silicon is presented. First and foremost, the design principle follows user safety since electrochemical etching of silicon requires highly hazardous electrolytes based on hydrofluoric (HF) acid. The novel cell design allows for safe electrolyte handling prior, during, and post-etching. A peristaltic pump with HF-resistant fluoroelastomer tubing transfers electrolytes between dedicated reservoirs and the anodization cell. Due to the flexibility of the cell operation, different processing conditions can be realized providing a large parameter range for the attainable sample thickness, its porosity, and the mean pore size. Rapid etching on the order of several minutes to synthesize micrometer-thick porous silicon epilayers on bulk silicon is possible as well as long-time etching with continuous, controlled electrolyte flow for several days to prepare up to 1000 µm thick self-supporting porous silicon membranes. A highly adaptable, LabVIEW™-based control software allows for user-defined etching profiles.

Popliteal Artery Entrapment Syndrome.

¼ Popliteal artery entrapment syndrome is a commonly misdiagnosed condition that should be considered in patients presenting with exertional lower-extremity pain. ¼ In addition to a focused physical examination, the ankle-brachial index and advanced imaging consisting of computed tomography and computed tomographic angiography or magnetic resonance imaging and magnetic resonance angiography are crucial in evaluating the underlying cause of entrapment. ¼ Consultation with a vascular surgeon or team is necessary when planning surgical treatment of popliteal artery entrapment syndrome.

Kinematics and center of mass mechanics during terrestrial locomotion in northern lapwings (Vanellus vanellus, Charadriiformes).

Avian bipedalism is best studied in derived walking/running specialists. Here, we use kinematics and center of mass (CoM) mechanical energy patterns to investigate gait transitions of lapwings-migratory birds that forage on the ground, and therefore may need a trade-off between the functional demands of terrestrial locomotion and long distance flights. The animals ran on a treadmill while high-speed X-ray videos were recorded within the sustainable speed range. Instantaneous CoM mechanics were computed from integrating kinematics and body segment properties. Lapwings exhibit similar locomotor characteristics to specialized walking/running birds, but have less distinct gaits. At slow speeds no clear separation between vaulting (i.e., walking) and bouncing (i.e., running) energy patterns exists. Mechanical energy recovery of non-bouncing gaits correlates poorly with speed and suggests inefficient use of the inverted pendulum mechanism. Speed ranges of gaits overlap considerably, especially those of grounded running, a gait with CoM mechanics indicative of running but without an aerial phase, and aerial phase running, with no preferential gait at most speeds. Compliant limb morphology and grounded running in birds can be regarded as an evolutionary constraint, but lapwings effectively make use of advantages offered by this gait for a great fraction of their speed range. Thus, effective usage of grounded running during terrestrial locomotion is suggested generally to be a part of striding avian bipedalism-even in species not specialized in walking/running locomotion.

Hierarchical Bayesian scaling of soil properties across urban, agricultural, and desert ecosystems.

Ecologists increasingly use plot-scale data to inform research and policy related to regional and global environmental change. For soil chemistry research, scaling from the plot to the region is especially difficult due to high spatial variability at all scales. We used a hierarchical Bayesian model of plot-scale soil nutrient pools to predict storage of soil organic carbon (oC), inorganic carbon (iC), total nitrogen (N), and available phosphorus (avP) in a 7962-km2 area including the Phoenix, Arizona, USA, metropolitan area and its desert and agricultural surroundings. The Bayesian approach was compared to a traditional approach that multiplied mean values for urban mesic residential, urban xeric residential, nonresidential urban, agricultural, and desert areas by the aerial coverage of each land-use type. Both approaches suggest that oC, N, and avP are correlated with each other and are higher (in g/m2) in mesic residential and agricultural areas than in deserts or xeric residential areas. In addition to traditional biophysical variables, cultural variables related to impervious surface cover, tree cover, and turfgrass cover were significant in regression models predicting the regional distribution of soil properties. We estimate that 1140 Gg of oC have accumulated in human-dominated soils of this region, but a significant portion of this new C has a very short mean residence time in mesic yards and agricultural soils. For N, we estimate that 130 Gg have accumulated in soils, which explains a significant portion of "missing N" observed in the regional N budget. Predictions for iC differed between the approaches because the Bayesian approach predicted iC as a function of elevation while the traditional approach employed only land use. We suggest that Bayesian scaling enables models that are flexible enough to accommodate the diverse factors controlling soil chemistry in desert, urban, and agricultural ecosystems and, thus, may represent an important tool for ecological scaling that spans land-use types. Urban planners and city managers attempting to reduce C emissions and N pollution should consider ways that landscape choices and impervious surface cover affect city-wide soil C, N, and P storage.

Lest formalisms impede insight and success: evaluation in health informatics--a case study.

OBJECTIVES: To illustrate the advantages of an open-ended formative evaluation approach using a project-specific selection of methods over the controlled trial approach in the evaluation of health information systems. To illustrate factors leading to success and others impeding it in a telehealth project. METHODS: The methods and results of an evaluation of the BC Telehealth Program are summarized. RESULTS: The evaluation gave a comprehensive picture of the project, including assessment of the effects of an array of telehealth applications, and their economic impact. Factors leading to success and others preventing it are identified from the level of overall program management to the project specifics. The results include unanticipated effects and explanations for their reasons of occurrence. Neither the comprehensiveness of information nor the timeliness was achieved in a related project using a controlled trial approach. CONCLUSIONS: Not all types of health information system projects can be evaluated using the controlled trial approach. This approach may impede important insights. It is also usually much less efficient. Funding agencies and journal editors have to take this into account when selecting projects for funding and submissions for publication.

Success factors for telehealth--a case study.

PURPOSE: To present the lessons learned from an evaluation of a comprehensive telehealth project regarding success factors and evaluation methodology for such projects. METHODS: A recent experience with the evaluation of new telehealth services in BC, Canada, is summarized. Two domains of clinical applications, as well as educational and administrative uses, and the project environment were evaluated. In order to contribute to the success of the project, the evaluation included formative and summative approaches employing qualitative and quantitative methods with data collection from telehealth events, participants and existing databases. The evaluation had to be carried out under severe budgetary and time constraints. We therefore deliberately chose a broad ranging exploratory approach within a framework provided, and generated questions to be answered on the basis of initial observations and participant driven interviews with progressively more focused and detailed data gathering, including perusal of a variety of existing data sources. A unique feature was an economic evaluation using static simulation models. RESULTS: The evaluation yielded rich and detailed data, which were able to explain a number of unanticipated findings. One clinical application domain was cancelled after 6 months, the other continues. The factors contributing to success include: Focus on chronic conditions which require visual information for proper management. Involvement of established teams in regular scheduled visits or in sessions scheduled well in advance. Problems arose with: Ad hoc applications, in particular under emergency conditions. Applications that disregard established referral patterns. Applications that support only part of a unit's services. The latter leads to the service mismatch dilemma (SMMD) with the end result that even those e-health services provided are not used. The problems encountered were compounded by issues arising from the manner in which the telehealth services had been introduced, in particular the lack of time for preparation and establishment of routine use. Educational applications had significant clinical benefits. Administrative applications generated savings which exceeded the substantial capital investment and made educational and clinical applications available at variable cost. CONCLUSION: Evaluation under severe constraints can yield rich information. The identified success factors, including provision of an overarching architecture and infrastructure, strong program management, thorough needs analysis and detailing applications to match the identified needs should improve the sustainability of e-health projects. Insights gained: Existing assumptions before the study was conducted: Evaluation has to proceed from identified questions according to a rigorous experimental design. Emergency and trauma services in remote regions can and should be supported via telehealth based on video-conferencing. Educational applications of telehealth directed at providers are beneficial for recruitment and retention of providers in remote areas. Insights gained by the study: An exploratory approach to evaluation using a multiplicity of methods can yield rich and detailed information even under severe constraints. Ad hoc and emergency clinical applications of telehealth can present problems unless they are based on thorough, detailed analyses of environment and need, conform to established practice patterns and rely on established trusting collaborative relationships. Less difficult applications should be introduced before attempting to support use under emergency conditions. Educational applications are of interest beyond the provider community to patients, family and community members, and have clinical value. In large, sparsely populated areas with difficult travel conditions administrative applications by themselves generate savings that compensate for the substantial capital investment for telehealth required for clinical applications.

Video conferencing-based telehealth--its implications for health promotion and health care.

PURPOSE: To review the experience with a province-wide telehealth system in Canada, and its implications for health care and health promotion. To explore whether group support systems (GSS) based on networked computers can substitute for video conferencing technology. METHODS: Key results of the evaluation of the BC Telehealth Program are summarized. The potential of extending the successful principles through use of GSS is explored based on literature review, demonstrations, and trial use for educational applications. RESULTS: The BC Telehealth Program was designed to support health professionals at secondary care facilities, such as regional and district hospitals in two application domains: children's and women's health (C&W) and emergency room and trauma care (ER-Trauma). Successful applications extended beyond health professionals and focused on chronic conditions, the management of which is contingent on visual information, and involves established teams in regular scheduled visits or in sessions scheduled well in advance. Ad hoc applications, in particular applications under emergency conditions proved problematic. Administrative applications in support of telehealth implementation, e.g., through facilitation of management and provider education, are essential for clinical success. Savings from support of administrative applications exceeded the substantial capital investment and made educational and clinical applications available at variable cost. Educational applications were shown to have significant clinical benefits. Exploration of GSS technology showed that it may not be mature enough to substitute for video conferencing technology in support of sophisticated training and education aiming at clinical impact. CONCLUSION: The substantial clinical and efficiency gains provided by video conferencing-based telehealth may for now continue to depend on mature video-conferencing technology.

Carbon and nitrogen transfer from a desert stream to riparian predators.

Adult aquatic insects emerging from streams may be a significant source of energy for terrestrial predators inhabiting riparian zones. In this study, we use natural abundance delta(13)C and delta(15)N values and an isotopic (15)N tracer addition to quantify the flow of carbon and nitrogen from aquatic to terrestrial food webs via emerging aquatic insects. We continuously dripped labeled (15)N-NH(4) for 6 weeks into Sycamore Creek, a Sonoran desert stream in the Tonto National Forest (central Arizona) and traced the flow of tracer (15)N from the stream into spiders living in the riparian zone. After correcting for natural abundance delta(15)N, we used isotopic mixing models to calculate the proportion of (15)N from emerging aquatic insects incorporated into spider biomass. Natural abundance delta(13)C values indicate that orb-web weaving spiders inhabiting riparian vegetation along the stream channel obtain almost 100% of their carbon from instream sources, whereas ground-dwelling hunting spiders obtain on average 68% of their carbon from instream sources. During the 6-week period of the (15)N tracer addition, orb-web weaving spiders obtained on average 39% of their nitrogen from emerging aquatic insects, whereas spider species hunting on the ground obtained on average 25% of their nitrogen from emerging aquatic insects. To determine if stream subsidies might be influencing the spatial distribution of terrestrial predators, we measured the biomass, abundance and diversity of spiders along a gradient from the active stream channel to a distance of 50 m into the upland using pitfall traps and timed sweep net samples. Spider abundance, biomass and richness were highest within the active stream channel but decreased more than three-fold 25 m from the wetted stream margin. Changes in structural complexity of vegetation, ground cover or terrestrial prey abundance could not account for patterns in spider distributions, however nutrient and energy subsidies from the stream could explain elevated spider numbers and richness within the active stream channel and riparian zone of Sycamore Creek.

Threats and assaults against psychiatrists.

In this article, the authors review the literature on surveys pertaining to threats and assaults on psychiatrists and report the results of a questionnaire sent to Oregon psychiatrists. Although the responding psychiatrists were experienced clinicians, they appear to have had relatively little life experience with aggression. Assaults and threats were frequent in their careers, occurred across a variety of clinical settings, and involved a wide range of patients. The authors discuss specific strategies for psychiatrists to minimize the effects of patient threats and assaults and suggest ways in which organized psychiatry can help with the danger and sequelae of patient violence.

Anticarcinogens from fried ground beef: heat-altered derivatives of linoleic acid.

Fried ground beef contains substances that inhibit mutagenesis in bacteria and the initiation of epidermal carcinogenesis in mice by 7,12-dimethylbenz [a]anthracene (DMBA). The inhibitors apparently act at least in part via inhibition of cytochrome P-450 activity. A highly purified fraction that inhibited cytochrome P-450 activity in vitro was isolated by HPLC and characterized by GC-MS, and by UV and proton NMR spectroscopy. The fraction contained four isomeric derivatives of linoleic acid each containing a conjugated double-bond system (designated CLA). Synthetically prepared CLA (containing all four isomers) was tested for anti-initiation activity in the two-stage mouse epidermal carcinogenesis system. Seven days, 3 days and 5 min prior to DMBA application, CLA was applied at doses of 20, 20 and 10 mg respectively. Control mice were treated similarly with linoleic acid or solvent (acetone). One week after initiation, and twice weekly thereafter, all mice were treated with 12-O-tetradecanoylphorbol-13-acetate to effect tumor promotion. There was no difference in tumor incidence or yield between linoleic acid-treated mice and solvent-treated control mice. By contrast, the CLA-treated mice developed only about half as many papillomas and exhibited a lower tumor incidence compared with the control mice.