Rapid crack growth in a thermoelastic solid under mixed-mode thermomechanical loading

A two-dimensional steady-sate analysis of semi-infinite brittlecrack growth at a constant subcritical rate in an unboundedfully-coupled thermoelastic solid under mixed-mode thermomechanicalloading is made. The loading consists of normal and shear tractionsand heat fluxes applied as point sources (line loads in theout-of-plane direction). A related problem is solved exactly in an integral transformspace, and robust asymptotic forms used to reduce the originalproblem to a set of integral equations. The equations are partiallycoupled and exhibit operators of both Cauchy and Abel types,yet can be solved analytically. The temperature change field at a distance from the moving crackedge is then constructed, and its dominant term is found tobe controlled by the imposed heat fluxes. The role of this termis, indeed, enhanced if the heat fluxes serve to render thecrack as a net heat source/sink for the solid, as opposed tobeing a transmitter of heat across its plane. More generally,the influence of the thermoelastic coupling on this field, aswell as other functions, is found to increase with crack speed.     

Synthetic magnetic opals

We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there exists no report in literature on any BiNi compound which is magnetic.     

Study of germ tube formation by Candida albicans after photodynamic antimicrobial chemotherapy (PACT)

Due to the augmented number of immunocompromised patients, the infections associated to the pathogen of the genus Candida have increased dramatically in the recent years. In order to proliferate, Candida albicans can produce a germ tube formation extending from the cells. The germ tube formation is a transition state from budding to hyphal cells, and represents an essential stage for virulence. In this work we studied the effect of the photodynamic antimicrobial chemotherapy (PACT), a potential antimicrobial treatment on the germ tube formation by C. albicans. Germ tube formation was induced by goat serum after different treatments with Methylene blue (MB) and Laser (683nm). Our results demonstrated that photodynamic therapy using MB, as a photosensitizing drug; inhibits both the growth and the germ tube formation by C. albicans. Thus, our results suggest the possibility that Methylene blue, combined with light in a specific wavelength, can be used as a promising novel antifungal agent.     

Functional neural network analysis in frontotemporal dementia and Alzheimer's disease using EEG and graph theory

Background  

Although a large body of knowledge about both brain structure and function has been gathered over the last decades, we still have a poor understanding of their exact relationship. Graph theory provides a method to study the relation between network structure and function, and its application to neuroscientific data is an emerging research field. We investigated topological changes in large-scale functional brain networks in patients with Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD) by means of graph theoretical analysis of resting-state EEG recordings. EEGs of 20 patients with mild to moderate AD, 15 FTLD patients, and 23 non-demented individuals were recorded in an eyes-closed resting-state. The synchronization likelihood (SL), a measure of functional connectivity, was calculated for each sensor pair in 0.5–4 Hz, 4–8 Hz, 8–10 Hz, 10–13 Hz, 13–30 Hz and 30–45 Hz frequency bands. The resulting connectivity matrices were converted to unweighted graphs, whose structure was characterized with several measures: mean clustering coefficient (local connectivity), characteristic path length (global connectivity) and degree correlation (network 'assortativity'). All results were normalized for network size and compared with random control networks.     

The role played by hydrogen in the ionic thermocurrents of beryl

Abstract

Ionic thermocurrents (ITC) were measured in pink (morganite) and colourless (goshenite) samples of natural beryl from 77K up to 250K at a constant rate b = 0.1 Ks^?1. The spectra present three distinct bands, at 170K, 200K and 220K. The band at 200K predominates in the untreated crystals. After thermal treatments between 700K and 1300K, the ITC bands at 170K and 220K become prominent, masking the 200K band. The reduction of Fe³⁺ into Fe²⁺ in two distinct positions in the beryl lattice justify this observation. Infrared (IR) spectra show that treatments above 1000K remove water from the channels of the beryls. Ultraviolet (UV) irradiation of these thermally treated samples enhance the two bands at 170K and 220K.