Spray deposition and property analysis of anatase phase titania (TiO2) nanostructures

Anatase phase titanium dioxide thin films have been deposited at various substrate temperatures by chemical spray pyrolysis of an aerosol of titanyl acetylacetonate. Deposited TiO₂ films were nanocrystalline and preferentially oriented along [101] direction, uniform and adherent to the glass substrate. Best films processed at 450 °C were characterized to analyze its phase composition, texture, roughness, optical and electrical properties. X-ray photoelectron spectroscopy revealed that the surface of the film has only the Ti⁴⁺ cations to form perfect TiO₂ stoichiometry with less amount of hydration. Atomic force microscopy image demonstrated the existence of homogeneous and rough surface, suitable for electrocatalytic applications. The film has an optical transmittance more than 90% and the refractive index of 2.07 was recorded at the wavelength 633 nm. Due to nano-sized grains, obtained optical band gap (3.65 eV) of the TiO₂ thin film was larger than that of the bulk TiO₂ (3.2 eV). Calculated porosity of the films 0.44, revealed the porous nature of the films. Hall measurements indicated that these materials are p-type and yield a carrier density of the order 8.8 × 10²⁰ cm⁻³ and a carrier mobility of 0.48 × 10⁻⁶ cm²/Vs. The dc electrical conductivity was therefore very low (8.91 × 10⁻⁶ S/cm) because of lower value of mean free path of the charge carriers (4.36 × 10⁻¹¹ cm). It gives an impression that the process of spray pyrolysis provides an easy way to tailor make thin films possessing superior properties.     

MALDI-TOF-MS analysis of droplets prepared in an electrodynamic balance: "wall-less" sample preparation

Methodology enabling mass spectral analysis of the composition of droplet(s) prepared in an electrodynamic balance (EDB) by matrix-assisted laser desorption/ionization (MALDI) is described. The dc field surrounding the electrodynamic balance was manipulated to eject single droplets at a time from the EDB thereby causing their deposition onto a MALDI sample plate precoated with matrix. When the laser was directed onto the droplet(s) and held stationary, marked gains in the signal-to-noise and signal-to-background ratios were realized with each subsequent mass spectrum due to the suppression of matrix cluster ion formation. Optical microscopy of the plate, after 1024 laser shots were fired at eight droplets that had been deposited one on top of the other, revealed a residual island of droplet matter (area approximately 3.1 x 10(-9) m2) inside the region where the crystalline matrix had been ablated away within the laser spot (area approximately 1.6 x 10(-8) m2). Removing the predried crystalline matrix layer and, instead, adding matrix into the starting solution was found to be a more effective means of suppressing matrix cluster ion formation. The chemical composition of the droplet(s) prepared in the EDB is discussed with regard to sample preconcentration, the images of the laser spot after MALDI, matrix cluster ion suppression, and the possibility for improved quantitation and detection limits by MALDI-TOF-MS.     

Pale vacuolated epithelial cells in epididymis of aflatoxin-treated mice

The responses of the mouse epididymal epithelium to subchronic doses of aflatoxin B1 were investigated in a histological study. Either few and large or small and profuse vacuoles containing an amorphous to dense periodic acid-Schiff-positive material were observed in the epithelium of all the segments of the epididymis. Resin-embedded semi-thin sections and transmission electron microscopy indicated that these vacuoles were intracellular. The cells that contained these vacuoles were quite different in organization and electron density from the cell types already established in the epididymal epithelium and are designated as pale vacuolated epithelial cells. Owing to aflatoxin B1 toxicity, the apical membrane of some of the principal cells, either individually or in groups, disintegrated so that the principal cells released their contents into the lumen of the duct through development of a 'fistula'. Spermatozoa from the ductal lumen entered the principal cell fistula and reached the basal lamina. If extravasation of the spermatozoa via this route occurred, it would bring about an autoimmune response, leading to the formation of spermatic granulomas and the generation of anti-sperm antibodies. Extravasation of spermatozoa seems to be offset by the underlying basal cell, which is presumed to develop into a pale vacuolated epithelial cell to enclose the disintegrating principal cells and the spermatozoa arriving at the principal cell. Thus, the development of pale vacuolated epithelial cells may be a protective device preventing an autoimmune response to sperm antigens in the context of toxicant-induced degeneration of the principal cells of the epididymal epithelium.     

AN INVESTIGATION OF ANDREWS' PLOTS TO SHOW TIME VARIATION OF MODEL PARAMETERS

Abstract. Andrews (1972) introduced a method of plotting high-dimensional data in two dimensions. This method is exploited as a graphical technique for the examination of changes over time in the parameters of a time series model. Two sets of data are used to illustrate the method. Both polynomial and Fourier series models are used. Some statistical properties of the method are discussed.     

Pharmacophore‐Based Design of Novel Oxadiazoles as Selective Sphingosine‐1‐phosphate (S1P) Receptor Agonists with in vivo Efficacy

Sphingosine‐1‐phosphate (S1P) receptor agonists have shown promise as therapeutic agents for multiple sclerosis (MS) due to their regulatory roles within the immune, central nervous system, and cardiovascular system. Here, the design and optimization of novel [1,2,4]oxadiazole derivatives as selective S1P receptor agonists are described. The structure–activity relationship exploration was carried out on the three dominant segments of the series: modification of the polar head group (P), replacement of the oxadiazole linker (L) with different five‐membered heterocycles, and the use of diverse 2,2′‐disubstituted biphenyl moieties as the hydrophobic tail (H). All three segments have a significant impact on potency, S1P receptor subtype selectivity, physicochemical properties, and in vitro absorption, distribution, metabolism, excretion and toxicity (ADMET) profile of the compounds. From these optimization studies, a selective S1P₁ agonist, N‐methyl‐N‐(4‐{5‐[2‐methyl‐2′‐(trifluoromethyl)biphenyl‐4‐yl]‐1,2,4‐oxadiazol‐3‐yl}benzyl)glycine ( 45 ), and a dual S1P_1,5 agonist, N‐methyl‐N‐(3‐{5‐[2′‐methyl‐2‐(trifluoromethyl)biphenyl‐4‐yl]‐1,2,4‐oxadiazol‐3‐yl}benzyl)glycine ( 49 ), emerged as frontrunners. These compounds distribute predominantly in lymph nodes and brain over plasma and induce long lasting decreases in lymphocyte count after oral administration. When evaluated head‐to‐head in an experimental autoimmune encephalomyelitis mouse model, together with the marketed drug fingolimod, a pan‐S1P receptor agonist, S1P_1,5 agonist 49 demonstrated comparable efficacy while S1P₁‐selective agonist 45 was less potent. Compound 49 is not a prodrug, and its improved property profile should translate into a safer treatment of relapsing forms of MS.     

Recent advances in cured raw ham manufacture

Cured raw hams are a valuable and popular group of meat products. The consumption and international trade have increased during the last years, therefore new technologies to accelerate the production process and to increase product quality and safety are needed. In the current review, an overview of European protected cured raw hams is presented. Furthermore, traditional methods for cured raw ham production together with recent advantages in the techniques for pretreatment (trimming, blade tenderization, and freeze-thawing), curing/salting (tumbling, vacuum impregnation, pulsed pressure, ultrasound, pulsed electric fields, simultaneous thawing/salting), drying/ripening (Quick-Dry-Slice-process, oil drop application, high temperature short time process) and postprocessing (vacuum and modified atmosphere packaging, high hydrostatic pressure, high pressure carbon dioxide, high pressure carbon dioxide with ultrasound) are described. Moreover, application techniques and effects of protective cultures and starter cultures, such as molds, yeasts, coagulase-negative staphylococci and lactic acid bacteria, on cured raw ham quality and safety are reviewed.     

The deterioration of semantic memory in Alzheimer's disease.

Semantic memory impairment is a common feature of dementia of the Alzheimer type (DAT). Recent research has shown that patients with DAT are more impaired (relative to non-demented controls) in generating exemplars from a particular semantic category (e.g., animals) than words beginning with a particular letter, exhibit an altered temporal dynamic during the production of category exemplars, are impaired on confrontation naming tasks and make predominantly superordinate or semantically related errors, consistently misidentify the same objects across a variety of semantic tasks, and have alterations in multidimensional scaling models of their semantic network that are indicative of a loss of concepts and associations. These results are consistent with the view that Alzheimer's disease results in a breakdown in the organization and structure of semantic knowledge as neurodegeneration spreads to the association cortices that presumably store semantic representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)