Using perturbation theory to compute the morphological similarity of diffusion tensors

Computing the morphological similarity of diffusion tensors (DTs) at neighboring voxels within a DT image, or at corresponding locations across different DT images, is a fundamental and ubiquitous operation in the postprocessing of DT images. The morphological similarity of DTs typically has been computed using either the principal directions (PDs) of DTs (i.e., the direction along which water molecules diffuse preferentially) or their tensor elements. Although comparing PDs allows the similarity of one morphological feature of DTs to be visualized directly in eigenspace, this method takes into account only a single eigenvector, and it is therefore sensitive to the presence of noise in the images that can introduce error intothe estimation of that vector. Although comparing tensor elements, rather than PDs, is comparatively more robust to the effects of noise, the individual elements of a given tensor do not directly reflect the diffusion properties of water molecules. We propose a measure for computing the morphological similarity of DTs that uses both their eigenvalues and eigenvectors, and that also accounts for the noise levels present in DT images. Our measure presupposes that DTs in a homogeneous region within or across DT images are random perturbations of one another in the presence of noise. The similarity values that are computed using our method are smooth (in the sense that small changes in eigenvalues and eigenvectors cause only small changes in similarity), and they are symmetric when differences in eigenvalues and eigenvectors are also symmetric. In addition, our method does not presuppose that the corresponding eigenvectors across two DTs have been identified accurately, an assumption that is problematic in the presence of noise. Because we compute the similarity between DTs using their eigenspace components, our similarity measure relates directly to both the magnitude and the direction of the diffusion of water molecules. The favorable performance characteristics of our measure offer the prospect of substantially improving additional postprocessing operations that are commonly performed on DTI datasets, such as image segmentation, fiber tracking, noise filtering, and spatial normalization.     

Doing double duty: power-line communications

In 2001, the German Minister of Economy passed several laws, allocating frequencies up to 30 MHz for the introduction of new technologies, such as power-line communications (PLC). The proposed PLC systems are designed to increase data to megabits per second, offering high speed Internet access. Interference to amateur radio operators and shortwave listeners is considered     

A 44 GHz monolithic semiconductor dipole antenna

Monolithic semiconductor antennas integrated with a diode detector have been fabricated using silicon-on-sapphire technology. The performance of these antennas is analyzed on the basis of earlier theoretical work on imperfectly conducting/resistive cylindrical dipoles. The measured radiation patterns of semiconductor antennas are compared with those of the corresponding printed metal dipoles.     

On a wing and a prayer [DARPA and MEMS]

Defense Advanced Research Projects Agency (DARPA) is offering funding for interdisciplinary research in the area of hybrid insect MEMS (microelectromechanical systems). DARPA aims to have MEMS intimately integrated into insects during their early stages of metamorphoses. In principle, this should lead to a more reliable bio-electromechanical interface to the insect, as compared with the earlier DARPA-funded attempts to glue the electronic module to an adult insect. DARPA's final demonstration goal is the delivery of an insect within five meters of a specific target located a hundred meters away using electronic remote control and/or GPS.     

Photophysical and charge-transporting properties of the copolymer SuperYellow

Conjugated copolymers are important materials for organic light-emitting diodes. Here, an investigation of the photophysical and charge-transporting properties of the prototypical poly(p-phenylene vinylene) based copolymer SuperYellow (SY) is reported. The study also investigated the effect of processing conditions by comparing the properties of spin-coated and solution-cast films. For both types of films, the results of time-resolved fluorescence and photoluminescence quantum yield measurements are similar. The high photoluminescence quantum yield of 60% and its independence of processing conditions shows the effectiveness of the bulky side groups in preventing concentration quenching of fluorescence. Time of flight measurements of charge mobility in both spin-coated and solution-cast films also showed similar results, with mobilities in the range 10^?6–10^?7 cm²/V s for both films. These results provide important information about a widely used copolymer and show that a good polymer light-emitting diode material can have low mobility.     

Monolithic semiconductor antennas for millimeter wave Si and GaAs integrated circuit technologies

It has been reported that the radiation characteristics of semiconductor antennas can be controlled by modulating their conductivity during fabrication and/or operation. This paper describes novel physical layouts integrating these versatile antennas with other components used in the realization of millimeter wave systems. The monolithic integration is discussed for GaAs as well as Si IC technologies.     

Non-dairy Based Probiotics: A Healthy Treat for Intestine

Dairy-based fermented products and yoghurts have been utilized as potential probiotic products since ancient times. However, recent upsurge in interest of consumers towards dairy alternatives has opened up new vistas for non-dairy probiotic research and development. Various matrices and substrates such as cereals, fruit juices, or mixture thereof are being utilized for delivering these beneficial microorganisms. Each matrix offers some advantages over the other. Vast knowledge available on a number of conventional fermented foods can also be utilized for future research in this area. The present review provides an insight on the recent research/developments in the field of non-dairy probiotic foods with particular reference to the foods consumed conventionally, in addition to their commercial availability and a way forward.     

Effect of Emulsion Droplet Size on Foaming Properties of Milk Fat Emulsions

Foamability and foam stability of dairy-based emulsions, as a function of emulsion droplet size ranging from micron- to nanometre-scale, were investigated. Fat phase (10 % w/w of anhydrous milk fat, stearin or olein fraction) was mixed with 2 % w/w protein solution (sodium caseinate or whey protein concentrate) and homogenised at 3, 10 and 35 MPa to obtain emulsions having particle sizes of about 1.20, 0.60 and 0.20 μm, respectively. The emulsions were cooled down and aged at 4 °C for 48 h to promote crystallisation. No fat coalescence was observed in any of the emulsions, as particle size distribution remained the same upon aging and whipping. It was shown that the smaller the particle size, the higher was the apparent viscosity and the lower was the solid fat content. Higher solid fat content tended to yield better foamability and foam stability. Destabilisation of air cells happened fastest with nanosized fat particles, resulting in shorter half-life of foam.     

Utilization of Food Processing By-products as Dietary,Functional, and Novel Fiber: A Review

Fast growing food processing industry in most countries across the world, generates huge quantity of by-products, including pomace, hull, husk, pods, peel, shells, seeds, stems, stalks, bran, washings, pulp refuse, press cakes, etc., which have less use and create considerable environmental pollution. With growing interest in health promoting functional foods, the demand of natural bioactives has increased and exploration for new sources is on the way. Many of the food processing industrial by-products are rich sources of dietary, functional, and novel fibers. These by-products can be directly (or after certain modifications for isolation or purification of fiber) used for the manufacture of various foods, i.e. bread, buns, cake, pasta, noodles, biscuit, ice creams, yogurts, cheese, beverages, milk shakes, instant breakfasts, ice tea, juices, sports drinks, wine, powdered drink, fermented milk products, meat products and meat analogues, synthetic meat, etc. A comprehensive literature survey has been carried on this topic to give an overview in the field dietary fiber from food by-products. In this article, the developments in the definition of fiber, fiber classification, potential sources of dietary fibers in food processing by-products, their uses, functional properties, caloric content, energy values and the labelling regulations have been discussed.