Functional near-infrared neuroimaging.

Functional near-infrared spectroscopy (fNIR) is a neroimaging modality that enables continuous, noninvasive, and portable monitoring of changes in blood oxygenation and blood volume related to human brain function. Over the last decade, studies in the laboratory have established that fNIR spectroscopy provides a veridical measure of oxygenation and blood flow in the brain. Our recent findings indicate that fNIR can effectively monitor cognitive tasks such as attention, working memory, target categorization, and problem solving. These experimental outcomes compare favorably with functional magnetic resonance imaging (fMRI) studies, and in particular, with the blood oxygenation level dependent signal. Since fNIR can be implemented in the form of a wearable and minimally intrusive device, it has the capacity to monitor brain activity under real life conditions and in everyday environments. Moreover, the fNIR system is amenable to integration with other established physiological and neurobehavioral measures, including electroencephalogram, eye tracking, pupil reflex, heart rate variability, respiration, and electrodermal activity.     

A fast partitioning method for PLA-based FPGAs

A method for automatic multipartitioning of a multiple-output logic function into the smallest number of subfunctions for mapping to fixed-size PLAs of a field-programmable gate array (FPGA) chip is described. A detailed example to demonstrate the procedure is presented. It is shown that, for this example, the method produced almost optimum partitions in a fast and efficient manner     

In vitro and in vivo evaluation of sustained-release and enteric-coated microcapsules of diclofenac sodium

This work examines the release of diclofenac sodium from ethylcellulose (EC) microcapsules made up of different drug to polymer ratios. The release process was found to follow the Higuchi square root equation and not the zero-order or first order equations. However, for drug to polymer ratio of 1:1, a critical time (θ) was reached beyond which the release rate was lower than that predicted on the basis of the Higuchi square root equation. Dissolution experiments in 0.1N HCL revealed that less than 1.5% of the encapsulated drug was released in 6 h. This finding indicates the suitability of the EC microcapsules for enteric-coated preparations. The in vitro release of diclofenac sodium from microcapsules of different drug to polymer ratios was compared with that from a commercial sustained-release product. A distinct similarity between the release profile of the commercial product with that obtained for the 1:2 drug to polymer microcapsules was noted. The in vivo work included determination of the serum drug profile following oral administration of the microcapsules and the commercial product to rabbits. The obtained serum concentration time profile of the EC microcapsules exhibited a sustained-release pattern similar to the commercial product and consistent with the in vitro results.     

On the phase error variance of a first-order phase-locked loop inthe presence of cochannel CW interference and additive noise

The qualitatively different behavior of the PLL phase error variance reported by Yoon and Lindsey (1982) and Sarkar (1990) under the same assumptions is examined. An error which appeared in Yoon and Lindsey is identified and corrected     

Utilization of solar earth-water stills for desalination of groundwater

Three solar earth-water stills of single-sloped type, designed for producing drinking water in remote areas, have been investigated. These stills were installed over an insulated hole, a hole with insulated base, and a hole with insulated walls. Multiple linear regression equations, relating to ambient air temperature, wind speed, and solar radiation, were developed to estimate the productivity of these stills. The study showed that condensation process inside these stills is achieved during the period between sunset and sunrise. Results showed also that the average wall's contribution in supplying fresh water is about 56%, whereas base contribution is about 31%. It is concluded, therefore, that setting many stills on a number of separated holes will give higher output rather than setting a single still on one large hole of the same volume.     

Thermoluminescence as a function of dose in natural Calcium Fluoride: A proposed mathematical model

The behavior of natural CaF₂ was studied for doses up to 50 Mrad. The response vs dose of the individual peaks and the total TL between 50 and 520°C was found to show the following properties: i) for sufficiently low values of dose the reponse is linear; ii) at higher values it becomes supralinear; and iii) at large values it approaches a constant level with the same shape glow curve. The effects of the dose received by the phosphor and the subsequent read out or annealing were clarified. A simple mathematical model is proposed to explain the mechanism by which the sensitivity of natural CaF₂ is increased.     

Nanotemplated platinum fuel cell catalysts and copper–tin lithium battery anode materials for microenergy devices

Nanotemplated materials have significant potential for applications in energy conversion and storage devices due to their unique physical properties. Nanostructured materials provide additional electrode surface area beneficial for energy conversion or storage applications with short path lengths for electronic and ionic transport and thus the possibility of higher reaction rates. We report on the use of controlled growth of metal and alloy electrodeposited templated nanostructures for energy applications. Anodic aluminium oxide templates fabricated on Si for energy materials integration with electronic devices and their use for fuel cell and battery materials deposition is discussed. Nanostructured Pt anode catalysts for methanol fuel cells are shown. Templated CuSn alloy anodes that possess high capacity retention with cycling for lithium microbattery integration are also presented.     

Production of egg-like silica sphere in a carbon shell and their oxidation to produce egg-tray structures with high ammonia adsorption

A simple synthesis protocol to prepare egg-like carbon-silica hybrids was developed where the size of a silica ball housed inside a carbon shell was tunable. An egg-tray type of carbon-silica hybrid was also made by the oxidation of egg-like carbon-silica hybrids. This oxidized hybrid has shown high ammonia adsorption capacity that is about 30 times more than the standard commercial adsorbent H-ZSM-5 (SiO₂/Al₂O₃=128).     

A Mathematical Model for Potassium Sorbate Diffusion Through Whey Protein Films

A mathematical model was constructed and solved to quantitatively describe the dynamic behavior of the potassium sorbate diffusion through whey protein films. The model results were compared with the experimental data of the potassium sorbate diffusion through whey protein films, and excellent agreements between the experimental data and the model results are observed. The experimental data for potassium sorbate diffusion through whey protein films were used for mathematical model of potassium sorbate diffusion through whey protein films and the determination of both potassium sorbate and solvent diffusion coefficients. The diffusivities of potassium sorbate at 25°C ranged from 4.12 to 9.34 × 10^?11 m²/s, while that of the solvent was between 1.38 and 8.74 × 10^?10 m²/s, depending on the film composition.