Photocatalytic titanium dioxide composite

In recent years, Titanium Dioxide (TiO2) has gained much more interest for its semiconducting properties for use as photocatalytic material because it rapidly and completely mineralizes organic without harmful byproducts. Based on inspiration from biology, which uses organic structures to guide nucleation and growth of minerals, we demonstrate controlled synthesis of TiO2 using a hydrophilic synthetic polymer. In the absence of the polymer, TiO2 completely transforms to rutile by 72 hours, however with the addition of the polymer larger anatase crystallites are observed due to the reduced number of nuclei formed. Under these conditions, complete transformation to rutile was not observed due to diffusion-limited growth of TiO2 as well as the presence of an organic coating on the crystallites. However nanoparticles are difficult to recover from effluent streams. We use the polymer to develop bulk composite TiO2-organic structures which can be fabricated and tailored as a stand alone photocatalysts, eliminating the need for nanoparticle recovery systems, thereby reducing processing costs.     

Chemical alignment of DNA origami to block copolymer patterned arrays of 5 nm gold nanoparticles

We have used block copolymer patterned arrays of 5 nm gold nanoparticles (AuNPs) for chemically aligned surface attachment of DNA origami. Addition of single-stranded DNA-thiol to AuNPs allowed a base paired attachment of sticky end modified DNA origami. Results indicate a stable, selective attachment between the DNA origami and ssDNA modified AuNPs. Yield data showed 74% of AuNP binding sites forming an attachment with a DNA origami rectangle, and control surfaces showed less than 0.5% nonspecific adsorption.     

探讨智能医疗设备需求迅速崛起的原因

医疗设备设计工程师一直面对开发病患护理的先进电子设备的挑战,在过去的十年左右,我们看到医疗设备市场出现了显著的进步,从易于使用的血压和血糖水平家庭监控装置,到医院手术室里使用的综合诊断成像设备、尖端机器人技术和激光外科设备都纷纷面世。医疗行业的一个重大发展趋势是逐渐采用与消费电子和通信行业相同的电子设计策略和组件,因而推动了这两个行业在最近几年实现快速增长。新     

Direct positioning of stationary targets using MIMO radar

MIMO radar is a new concept that has recently been proposed as an extension to the multi-static radar systems. We apply the direct position determination (DPD) approach to MIMO radar and obtain maximum likelihood algorithms for a location estimation of a stationary target. It is shown that under low signal to noise ratio DPD improves the estimation accuracy with respect to the traditional location methods.     

Chaos Communication Performance: Theory and Computation

In this paper new and existing approaches are developed to compute the bit-error rate for chaos-based communication systems. The multi-user coherent antipodal chaos shift keying system is studied and evaluated in its coherent form, in the sense of perfect synchronisation between transmitted and received chaotic sequences. Transmission is through an additive white Gaussian noise channel. Four methods are interrelated in the paper, three approximate ones and an exact one. The least accurate but most well known is based on simple Gaussian approximation; this is generalised to better reveal its structure. Two accurate and computationally efficient approximate methods are based on conditional Gaussian approximation and the statistical distribution of the typically non-constant bit energy. The most insightful but computationally expensive one is based on exact theory and rests on explicit mathematical results for particular chaotic maps used to spread binary messages. Both upper and lower bounds to the bit-error rate are suggested. The relative advantages of the different approaches are illustrated with plots of bit-error rate against signal to noise ratio.     

Molecular Dynamics Simulation of MBE Growth of CdTe/ZnTe/Si

We simulate in three dimensions molecular beam epitaxial (MBE) growth of CdTe/ZnTe/Si using classical molecular dynamics. Atomic interactions are simulated with Stillinger–Weber potentials, whose parameters are obtained by fitting to experimental data or density function theory-calculated distortion energies of the component crystals. The effects of substrate temperature and atomic species flux ratios on epilayer morphology are investigated. The agreement between simulations and experiments suggests that this model has reasonable ability to predict the microstructures of CdTe/ZnTe/Si grown by MBE.     

Comparative behaviour of cellulosic and starchy plant materials during osmotic dehydration

Osmotic dehydration studies on two cellulosic plant materials—Golden Delicious and Cox apple—and two starchy plant materials—banana and potato—showed that the amount and rate of water loss occurred in the following descending order: Golden Delicious > Cox > potato > banana. Temperature, concentration and immersion time of samples in the osmotic solution played a significant effect on amount and rate of water loss in all commodities in a descending order as follows: 55 > 40 > 32.2 °C; 0.70 > 0.60 > 0.50 > 0.40 g kg^?1; and 30 > 60 > 90 > 120 min, respectively. A corresponding uptake of solids from the osmotic solution occurred, the rate been greatest over the first 30 min, before declining significantly thereafter. The diffusion coefficients for water loss (D_{eff, w}) measured by the method of slopes on the water loss rate curves conducted at 32.2, 40 and 55 °C for 0.40, 0.50, 0.60 and 0.70 g kg^?1 sucrose concentration solutions were higher for cellulosic plant materials than starchy plant materials. Significant variations occurred in efficiency index (WL/SG) between cellulosic and starchy plant materials. Copyright © 2007 Society of Chemical Industry     

Improvement by oxidising agents of the baking performance of pure and composite flours from nigerian-grown wheats (Lee X and Inia 66)

The feasibility of improving the bread-baking performance of two varieties of Nigerian-grown wheat (Lee X and Inia 66) in pure and composite flour, using the oxidising agents potassium bromate and ascorbic acid was studied. Composite flour was prepared by mixing pre-cooked bambara bean (Voandzeia subterranean) flour at levels between 0 and 50% with each of commercial (control), Lee X and Inia 66 wheat flour. Physical and sensory evaluations showed that the performance of straight Lee X and Inia 66 flours was inferior to that of the commercial flour. The commercial flour showed better tolerance to blending with bambara flour, producing acceptable loaves at up to 20% substitution with bean flour; Lee X and Inia 66 could not tolerate blending beyond 15% and 5% levels, respectively. Physical properties and baking performance of the Lee X and Inia 66 flours were improved by treatment with various levels of the oxidising agents KBrO₃, ascorbic acid and KBrO₃/ascorbic acid combinations. Lee X flour was more responsive to the treatments than Inia 66. Concentrations of 25 mg kg^?1 KBrO₃ and 80 mg kg^?1 ascorbic acid singly were found to improve Lee X flours adequately, but a combination of the two agents at a level of 25/60 mg kg^?1 KBrO₃/ascorbic acid was optimal. When treated with the optimal level of improver combination, Lee X flour performed as well as the commercial flour; and treated Lee X composite flours containing up to 30% pre-cooked bambara flour were found to produce loaves not significantly different from 100% commercial wheat bread (P≤0.05).     

Heat-induced and other chemical changes in commercial UHT milks

The properties of commercial directly and indirectly heated UHT milks, both after heating and during storage at room temperature for 24 weeks, were studied. Thermally induced changes were examined by changes in lactulose, furosine and acid-soluble whey proteins. The results confirmed previous reports that directly heated UHT milks suffer less heat damage than indirectly heated milk. During storage, furosine increased and bovine serum albumin in directly heat-treated milks decreased significantly. The changes in lactulose, alpha-lactalbumin and beta-lactoglobulin were not statistically significant. The data suggest that heat treatment indicators should be measured as soon as possible after processing to avoid any misinterpretations of the intensity of the heat treatment.     

Thermal and refining processes, not fermentation, tend to reduce lipotropic capacity of plant-based foods

Plant-based foods (PBF) are relevant and diversified sources of lipotropes, which are compounds preventing excess hepatic fat deposits. In a first study, we defined the lipotropic capacity (LC, %) of raw PBF as the means of 8 lipotrope densities (LD, mg/100 kcal), each expressed relative to that of a reference food ranking the highest considering its mean 8 LD ranks (LC(raw asparagus)=100%) (A. Fardet, J.-F. Martin and J. M. Chardigny, J. Food Comp. Anal., 2011, DOI: 10.1016/j.jfca.2011.1003.1013). We showed that vegetables appeared as the best source of lipotropes on a 100 kcal-basis compared to legumes, cereals, fruits and nuts. The main objective of this second study was to quantify the effect of processing on LD and LC of raw PBF based on lipotrope contents collected in a USDA (United State Department of Agriculture) database and the literature, i.e. betaine, choline, myo-inositol, methionine, magnesium, niacin, pantothenic acid and folate contents. Choline and betaine densities were not significantly affected by processing while methionine and lipotropic micronutrient densities were significantly decreased, especially for magnesium, pantothenate and folates. Myo-inositol density decreases were insignificant due to lower product number resulting from limited literature data. Lipotropic micronutrient densities were more affected by processing than other densities. Fermentations increased betaine (median change of +32%) and choline (+34%) densities. Canning and boiling vegetables increased choline densities (+26%). Globally, processing significantly reduced LC by ～20%, fermentations being less drastic (median change of -5%) than refining (-33%) and thermal treatments (-16%). More specifically, canning increased LC of beetroot (536 vs 390%) and common bean (40 vs 36%) as fermentation towards LC grape (14 vs 7% for wine). Results were then mainly discussed based on percentages of lipotrope content changes on a dry-weight basis. Results of this study also showed that the LC is quite a relevant index to estimate effect of processing on lipotropic potential of PBF.