Role of nitric oxide in medullary raphe-evoked inhibition of neuronal activity in the periaqueductal gray matter

In male urethane-anaesthetized rats, activation of neurons in nucleus raphe obscurus and the caudal tip of nucleus raphe magnus by microinjection of 50-100 nl 0.1 M D,L-homocysteic acid produced a 75.6 +/- 5.2% reduction in the firing rate in 25 neurons in the lateral and dorsolateral sectors of the periaqueductal gray matter which lasted for 102.3 +/- 13.3s (mean +/- S.E.M.). The duration of the inhibition was significantly reduced in a dose-dependent manner by intracerebroventricular injection of the inhibitor of nitric oxide synthase, N(w)-nitro-L-arginine methyl ester (50-500 micrograms) but not by N(w)-nitro-D-arginine methyl ester (500 micrograms). In contrast, the magnitude of the raphe-evoked inhibition, i.e. the maximum depression of firing rate, was not significantly affected by either isomer. The results suggest that nitric oxide plays a role in the regulation of the excitability of neurons in the midbrain aversive system by the medullary raphe. The selective effect of the nitric oxide synthase inhibitor on the duration, but not the magnitude, of the raphe-evoked inhibition suggests that nitric oxide is not involved in initiating the inhibition. Rather, its role appears to be in maintaining the raphe-evoked inhibition once it has been initiated by a non-nitrergic mechanism.     

School behavior check list: An inventory of deviant behavior for elementary school children.

Modified Ross' Pittsburgh Adjustment Survey Scales to form 7 scales, designated the School Behavior Check List, for teacher ratings of children's deviant behavior. Factor structure for each sex was identical, although mean scale scores differed significantly. The T-score norms were then computed from a general sample of elementary schoolchildren (N = 5,373) for male, female, and total populations. Analyses of variance showed that scales were affected by sex, race, socioeconomic level, and IQ. The Total Disability scale and IQ were inversely correlated (-.42). A 2nd-order factor analysis revealed 1 dimension, achievement competence. The scales appear to be useful instruments, and the inverse relationship between IQ and psychopathology may have major theoretical implications. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mental illness stigma and the fundamental components of supported employment.

Purpose/Objective: The success of supported employment programs will partly depend on the endorsement of stigma in communities in which the programs operate. In this article, the authors examine 2 models of stigma--responsibility attribution and dangerousness--and their relationships to components of supported employment-help getting a job and help keeping a job. Research Method/Design: A stratified and randomly recruited sample (N=815) completed responses to a vignette about "Chris," a person alternately described with mental illness, with drug addiction, or in a wheelchair. Research participants completed items that represented responsibility and dangerousness models. They also completed items representing 2 fundamental aspects of supported employment: help getting a job or help keeping a job. Results: When participants viewed Chris as responsible for his condition (e.g., mental illness), they reacted to him in an angry manner, which in turn led to lesser endorsement of the 2 aspects of supported employment. In addition, people who viewed Chris as dangerous feared him and wanted to stay away from him, even in settings where people with mental illness might work. Conclusions/ Implications: Implications for understanding supported employment are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of an England-wide indoor overheating and air pollution model using artificial neural networks

With the UK climate projected to warm in future decades, there is an increased research focus on the risks of indoor overheating. Energy-efficient building adaptations may modify a buildings risk of overheating and the infiltration of air pollution from outdoor sources. This paper presents the development of a national model of indoor overheating and air pollution, capable of modelling the existing and future building stocks, along with changes to the climate, outdoor air pollution levels, and occupant behaviour. The model presented is based on a large number of EnergyPlus simulations run in parallel. A metamodelling approach is used to create a model that estimates the indoor overheating and air pollution risks for the English housing stock. The performance of neural networks (NNs) is compared to a support vector regression (SVR) algorithm when forming the metamodel. NNs are shown to give almost a 50% better overall performance than SVR.     

The effect of polymer coatings on proton transverse relaxivities of aqueous suspensions of magnetic nanoparticles

Iron oxide magnetic nanoparticles are good candidates for magnetic resonance imaging (MRI) contrast agents due to their high magnetic susceptibilities. Here we investigate 19 polyether-coated magnetite nanoparticle systems comprising three series. All systems were synthesized from the same batch of magnetite nanoparticles. A different polyether was used for each series. Each series comprised systems with systematically varied polyether loadings per particle. A highly significant (p < 0.0001) linear correlation (r = 0.956) was found between the proton relaxivity and the intensity-weighted average diameter measured by dynamic light scattering in the 19 particle systems studied. The intensity-weighted average diameter measured by dynamic light scattering is sensitive to small number fractions of larger particles/aggregates. We conclude that the primary effect leading to differences in proton relaxivity between systems arises from the small degree of aggregation within the samples, which appears to be determined by the nature of the polymer and, for one system, the degree of polymer loading of the particles. For the polyether coatings used in this study, any changes in relaxivity from differences in water exclusion or diffusion rates caused by the polymer are minor in comparison with the changes in relaxivity resulting from variations in the degree of aggregation.     

Underdetermined blind source separation of temporomandibular joint sounds

The underdetermined blind source separation problem using a filtering approach is addressed. An extension of the FastICA algorithm is devised which exploits the disparity in the kurtoses of the underlying sources to estimate the mixing matrix and thereafter achieves source recovery by employing the ll-norm algorithm. Besides, we demonstrate how promising FastICA can be to extract the sources. Furthermore, we illustrate how this scenario is particularly appropriate for the separation of temporomandibular joint (TMJ) sounds.     

In vivo near-infrared spectroscopy of rat skin tissue with varying blood glucose levels

We have performed in vivo measurements of near-infrared rat skin absorption in the 4000-5000-cm(-1) spectral range (2.0-2.5-microm wavelength) during a glucose clamp experiment in order to identify the presence of glucose-specific spectral information. Spectra were collected during an initial 3-h period where the animal's blood glucose concentration was held at its normal value. The blood glucose level was then increased above 30 mM by venous infusion of glucose and held for 2 h, after which it was allowed to return to normal. Spectra were recorded continuously during the procedure and are analyzed to identify spectral changes associated with changes in glucose concentration. Because the change in absorbance due to an increase in glucose concentration is small compared to changes due to other variations (e.g., the thickness of the skin sample), a simple subtraction of absorbance spectra from the hyperglycemic and euglycemic phases is not instructive. Instead, a set of principal components is established from the euglycemic period where the glucose concentration is constant. We then examine the change in absorbance during the hyperglycemic period that is orthogonal to these principal components. We find that there are significant similarities between these orthogonal variations and the net analyte signal of glucose, which suggests that glucose spectral information is present. The analysis described here provides a procedure by which the analytical significance of a multivariate calibration can be evaluated.     

Positive illusions and well-being revisited: Separating fact from fiction.

S. E. Taylor and J. D. Brown (see record 1992-16903-001) published an article that challenged the notion that accurate perceptions of self and the world are essential for mental health. The authors argued instead that people's perceptions in these domains are positively biased and that these positive illusions promote psychological well-being. In the current article, the authors review their theoretical model, correct certain misconceptions in its empirical application, and address the criticisms made by C. R. Colvin and J. Block (see record 1994-41047-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)