Microfabricated Lamb wave device based on PZT sol-gel thin film formechanical transport of solid particles and liquids

The fabrication using silicon micromachining and characterization of an acoustic Lamb wave actuator is presented. The intended use of the device is for mass transport and sensor applications. The device consists of dual interdigitated transducers patterned on a thin-film composite membrane of silicon nitride, platinum, and a sol-gel-derived piezoelectric ceramic (PZT) thin film. The acoustic properties of the device are presented along with preliminary applications to mechanical transport and liquid delivery systems. Improved acoustic signals and improved mass transport are achieved with PZT over present Lamb wave devices utilizing ZnO or AlN as the piezoelectric transducer     

One-year prevalence of psychiatric disorder in Ontarians 15 to 64 years of age

OBJECTIVE: To present the one-year prevalence of 14 psychiatric disorders in a community sample of Ontarians aged 15 to 64 years. METHOD: Data on psychiatric disorders were collected on 9953 respondents using the University of Michigan revision of the Composite International Diagnostic Interview (UM-CIDI). DSM-III-R criteria were used to define the psychiatric disorders. RESULTS: Almost 1 in 5 Ontarians (18.6%) had one or more of the disorders measured in the survey. Among 15-to 24-year-olds, 1 in 4 was affected. The distribution of individual disorders varied by sex and age. CONCLUSION: Because of the immense burden of suffering associated with psychiatric disorders, clinical and research efforts in this area should receive high priority within the health budget.     

Development of a web-based insulin decision aid for the elderly: usability barriers and guidelines

Universal Access in the Information Society - In recent years, researchers have attempted to shift patient decision aids (PDAs) from paper-based to web-based to increase its accessibility. Insulin...     

Leveraging online communities in fostering adaptive schools

There has long been a call for schools to prepare students for the twenty-first century where skills and dispositions differ significantly from much of what has historically characterized formal education. The knowledge based economy calls for policy and pedagogical efforts that would transform schools. Schools are to foster communities of learners. This paper suggests that para-communities may be points of leverage in the fostering of adaptive schools. A critical analysis is done on the differences between para-communities (such as online communities) and schools; and an argument is made that they each serve differing goals and should be left distinct because they achieve different societal and economic demands.     

Remote sensing of vegetation and land-cover change in Arctic Tundra Ecosystems

The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land-Air-Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonstrate that ground-level sensors on stationary or moving track platforms and wide-swath imaging sensors on polar orbiting satellites are particularly useful for capturing optical remote sensing data at sufficient frequency to study tundra vegetation dynamics and changes for the cloud prone Arctic. Less frequent imaging with high spatial resolution instruments on aircraft and lower orbiting satellites enable more detailed analyses of land cover change and calibration/validation of coarser resolution observations.The strongest signals of ecosystem change detected thus far appear to correspond to expansion of tundra shrubs and changes in the amount and extent of thaw lakes and ponds. Changes in shrub cover and extent have been documented by modern repeat imaging that matches archived historical aerial photography. NOAA Advanced Very High Resolution Radiometer (AVHRR) time series provide a 20-year record for determining changes in greenness that relates to photosynthetic activity, net primary production, and growing season length. The strong contrast between land materials and surface waters enables changes in lake and pond extent to be readily measured and monitored.     

Surface graft copolymerization enhanced adhesion of an epoxy-basedprinted circuit board substrate (FR-4) to copper

The lamination of surface modified printed circuit board (PCB) substrate, FR-4(R), from argon plasma pretreatment and UV-induced graft copolymerization with glycidyl methacrylate (GMA), to copper foil was carried out at elevated temperature and in the presence of an epoxy adhesive. The structure and chemical composition of the graft copolymerized surfaces and interfaces of the glass fiber-reinforced and epoxy-based FR-4 substrates were studied by X-ray photoelectron spectroscopy (XPS). The effects of the plasma pretreatment time, the UV illumination time, as well as the curing temperature, on the adhesion strength between the FR-4 substrate and copper were investigated. The assemblies involving GMA graft copolymerized FR-4, or the FR-4-GMA/epoxy resin/Cu assemblies, exhibited a significantly higher interfacial adhesion strength and reliability, in comparison to those assemblies in which only epoxy adhesive alone was used. The enhanced adhesion in the assemblies involving GMA graft copolymerized substrate arises from the fact that the covalently tethered GMA graft chains on the FR-4 surface can become covalently incorporated into the epoxy resin, resulting in the toughening of the epoxy matrix and increased interaction with copper     

Capillary electrochromatography of cholesterol and its ester derivatives

Separation of cholesterol and its ester derivatives using micellar electrokinetic chromatography is a challenge due to the extreme hydrophobicity of these compounds. In this work, an isocratic capillary electrochromatography (CEC) method has been developed to separate a complex mixture of cholesterol and its 12-ester derivatives. The proportions of mobile phase (tetrahydrofuran, acetonitrile, water), as well as the effects of acid modifiers, buffer concentrations, voltage, and temperature on the separation of cholesterol derivatives were investigated. Addition of a polymeric surfactant, poly(sodium N-undecanoyl-L-glycinate), to the mobile phase reduced migration time and improved resolution of the analytes. The CEC method developed allows baseline separation of a complex mixture of cholesterol and 12 ester derivatives in less than 40 min. Finally, the method is applied to the characterization of cholesterol, cholesterol linoleate, and cholesterol oleate extracted from atherosclerotic plaque deposits in the arterial walls of a human aorta.     

Statistical inference, the bootstrap, and neural-network modelingwith application to foreign exchange rates

We propose tests for individual and joint irrelevance of network inputs. Such tests can be used to determine whether an input or group of inputs "belong" in a particular model, thus permitting valid statistical inference based on estimated feedforward neural-network models. The approaches employ well-known statistical resampling techniques. We conduct a small Monte Carlo experiment showing that our tests have reasonable level and power behavior, and we apply our methods to examine whether there are predictable regularities in foreign exchange rates. We find that exchange rates do appear to contain information that is exploitable for enhanced point prediction, but the nature of the predictive relations evolves through time.     

Converging inputs to the entorhinal cortex from the piriform cortex and medial septum: facilitation and current source density analysis

Converging inputs to the entorhinal cortex from the piriform cortex and medial septum: facilitation and current source density analysis. J. Neurophysiol. 78: 2602-2615, 1997. The entorhinal cortex receives sensory inputs from the piriform cortex and modulatory inputs from the medial septum. To examine short-term synaptic facilitation effects in these pathways, current source density (CSD) analysis was used first to localize the entorhinal cortex membrane currents, which generate field potentials evoked by stimulation of these afferents. Field potentials were recorded at 50-micron intervals through the medial entorhinal cortex in urethan-anesthetized rats and the one-dimensional CSD was calculated. Piriform cortex stimulation evoked a surface-negative, deep-positive field potential component in the entorhinal cortex with mean onset and peak latencies of 10.4 and 18.4 ms. The component followed brief 100-Hz stimulation, consistent with a monosynaptic response. CSD analysis linked the component to a current sink, which often began in layer I before peaking in layer II. A later, surface-positive field potential component peaked at latencies near 45 ms and was associated with a current source in layer II. Medial septal stimulation evoked positive and negative field potential components which peaked at latencies near 7 and 16 ms, respectively. A weaker and more prolonged surface-negative, deep-positive component peaked at latencies near 25 ms. The early components were generated by currents in the hippocampal formation, and the late surface-negative component was generated by currents in layers II to IV of the entorhinal cortex. Short-term facilitation effects in conscious animals were examined using electrodes chronically implanted near layer II of the entorhinal cortex. Paired-pulse stimulation of the piriform cortex at interpulse intervals of 30 and 40 ms caused the largest facilitation (248%) of responses evoked by the second pulse. Responses evoked by medial septal stimulation also were facilitated maximally (59%) by a piriform cortex conditioning pulse delivered 30-40 ms earlier. Paired pulse stimulation of the medial septum caused the largest facilitation (149%) at intervals of 70 ms, but piriform cortex evoked responses were facilitated maximally (46%) by a septal conditioning pulse 100-200 ms earlier. Frequency potentiation effects were maximal during 12- to 18-Hz stimulation of either the piriform cortex or medial septum. Occlusion tests suggested that piriform cortex and medial septal efferents activate the same neurons. The CSD analysis results show that evoked field potential methods can be used effectively in chronically prepared animals to examine synaptic responses in the converging inputs from the piriform cortex and medial septum to the entorhinal cortex. The short-term potentiation phenomena observed here suggest that low-frequency activity in these pathways during endogenous oscillatory states may enhance entorhinal cortex responsivity to olfactory inputs.     

Mental health supplement to the Ontario Health Survey: methodology

OBJECTIVE: To describe the methodology of a province-wide, cross-sectional, epidemiologic study of psychiatric disorder among those aged 15 years and over living in household dwellings in Ontario. METHOD: Respondents for the survey were drawn from households (N = 13002) participating in a province-wide health survey. One person per household was selected, and 9953 (76.5%) participated. RESULTS: Participants and nonparticipants were similar to each other. An extensive array of data, including measures of psychiatric disorder classified using a revised version of the Composite International Diagnostic Interview (CIDI), are available for all respondents. CONCLUSIONS: The Ontario Health Supplement is contained in a public-use data file at the Ontario Ministry of Health and is available to investigators for study. A strong survey design, careful measurement, and acceptable levels of response provide the rationale for our inviting researchers to access and use the Ontario Health Supplement data base.