Suppression of multiple pulse formation in external-cavitymode-locked semiconductor lasers using intrawaveguide saturableabsorbers

Imperfect antireflection coatings in external-cavity mode-locked semiconductor lasers can cause multiple output pulse generation. The incorporation of an intrawaveguide saturable absorber segment into the laser suppresses this problem. Single pulse outputs of less than 2.8 ps and 0.7 pJ of energy are obtained using such devices with both quantum well and bulk active regions     

Selective mutism: A review of the treatment literature by modality from 1980–1996.

Psychodynamic, family systems, behavioral, and psychopharmacological interventions of selective mutism are reviewed and discussed to examine effectiveness of treatment styles. Each modality has its own conceptualization of the disorder and specialized intervention techniques. While methodologies of the studies reviewed were often weak, there exist many treatment examples that illustrate effective interventions for selective mutism in childhood. The interventions that involved individualized or multimodal treatments produced the best overall results as evidenced through the symptom cessation. Many articles reported a close relationship between selective mutism and anxiety disorders. A clearer diagnostic understanding of selective mutism needs to be realized prior to generalizing a specific, effective treatment for this disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trehalose improves flavour retention in dehydrated apricot puree

The influence of the addition of two sugars (trehalose and sucrose) on the retention of volatiles responsible for the characteristic aroma in dehydrated apricot puree was studied. Aroma compounds of fresh and both freeze‐dried and foam‐mat‐dried apricot puree were analysed by manual headspace solid‐phase microextraction coupled with gas chromatography (GC‐FID and GC‐MS). The best retention of aroma compounds in dehydrated apricot puree was obtained when trehalose was added, regardless of the dehydration process used (freeze drying or foam‐mat drying), although, generally, a much higher retention of flavour volatiles was obtained in freeze‐dried purees. Principal Component Analysis and Cluster Analysis were applied to all the apricot purees studied to obtain a simplified view of the relationship among the aroma compounds in dehydrated apricot purees. This study gives further insights into the mechanisms that occur when trehalose is applied as an additive and will enable the development of new processes to maximize this effect and to produce superior dried products.     

Determination of reduced glutathione using an amperometric carbon paste electrode chemically modified with TTF–TCNQ

The development of an amperometric sensor for the determination of reduced glutathione (GSH) is described. The sensor is based on tetrathiafulvalene–tetracyanoquinodimethane (TTF–TCNQ) incorporated into the graphite powder/Nujol oil matrix. The electrooxidation of GSH was monitored amperometrically at 200 mV versus SCE (saturated calomel electrode). The amperometric response of the sensor was linearly proportional to the GSH concentration between 20 and 300 μmol l⁻¹, in 0.1 mol l⁻¹ phosphate buffer (pH 8.0), containing 0.1 mol l⁻¹ KCl and 0.5 mmol l⁻¹ Na₂H₂EDTA, as supporting electrolyte.

The detection limit, considering signal/noise ratio equal three, was 4.2 μmol l⁻¹ for GSH and the repeatability obtained as relative standard deviation was of 5.1% for a series of 10 successive measurements.     

EVALUATION OF FUNGAL CONTAMINATIONS ON BARLEY AND MALT

Methods for evaluation of fungal contamination on barley and malt have been collaboratively tested by a Sub-Group of the EBC Microbiology Group. Three methods are recommended: one general method, one method for Fusarium on barley and one method for storage fungi.     

A psychoeducational approach to prevent HIV transmission among injection drug users.

Describes a psychoeducational approach to AIDS risk reduction for injection drug users. The psychoeducational strategy not only provides information, but also focuses on psychological principles useful in the promotion of behavior change. The intervention is divided into 3 sessions covering (1) injection equipment sterilization and risk reduction in relation to drug use, (2) condom use and risk reduction for sexual activities, and (3) discussion of HIV antibody testing and a review. This program was designed as a small-group intervention for injection drug users within the context of an ongoing drug rehabilitation program. The content was customized to a target population of primarily African-American men who abuse cocaine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Use of Mass Isotopomer Distribution Analysis to Quantify Synthetic Rates of Sex Pheromone in the Moth <Emphasis Type="Italic">Heliothis virescens</Emphasis>

Although there has been much investigation of the steps involved in sex pheromone biosynthesis in moths, little is known about the kinetics of biosynthesis in vivo, primarily because there are few techniques suitable for studying the small amounts of pheromone produced without perturbing a female moth’s normal physiology. In this paper, female Heliothis virescens moths fed on U-¹³C-glucose were subjected to mass isotopomer distribution analysis, enabling calculation of fractional (FSR) and absolute (ASR) synthetic rates of the main pheromone component, (Z)-11-hexadecenal, at two different photoperiodic times: during the scotophase (when adults are sexually active) and during the photophase (when adults do not engage in mating behavior). FSRs differed substantially at the two times with, as expected, the greater rate occurring during the scotophase. After determining Z11-16:Ald pool sizes, ASR through the scotophase was calculated to be roughly 20 times greater than ASR in the photophase. These differences are consistent with the release/non-release of the pheromone biosynthesis-activating neuropeptide. This approach should facilitate determination of more quantitative measures of semiochemical production in moths and other sugar-feeding insects that synthesize semiochemicals from glycolytic metabolites.     

Impact of Materials versus Geometric Parameters on the Contact Resistance in Organic Thin‐Film Transistors

The contact resistance is known to severely hamper the performance of organic thin‐film transistors, especially when dealing with large injection barriers, high mobility organic semiconductors, or short channel lengths. Here, the relative significance of how it is affected by materials‐parameters (mobility and interfacial level‐offsets) and geometric factors (bottom‐contact vs top‐contact geometries) is assessed. This is done using drift‐diffusion‐based simulations on idealized device structures aiming at a characterization of the “intrinsic” situation in the absence of traps, differences in the film morphology, or metal‐atoms diffusing into the organic semiconductor. It is found that, in contrast to common wisdom, in such a situation the top‐contact devices do not always outperform the bottom‐contact ones. In fact, the observed ratio between the contact resistances of the two device structures changes by up to two orders of magnitude depending on the assumed materials parameters. The contact resistance is also shown to be strongly dependent on the hole mobility in the organic semiconductor and influenced by the chosen point of operation of the device.