1,055 research outputs found

    Mathematical models for radiation transfer

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    A radiation transfer model was modified to include semitransparent and opaque layers as well as molecular constituents. An example of the use of the program and an analysis of the mathematical model are included

    Interbacterial signaling via Burkholderia contact-dependent growth inhibition system proteins

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    How bacteria interact with one another has implications for human health and disease because complex bacterial communities like biofilms can impact agriculture, infection transmission, and disease progression. Contact-dependent growth inhibition systems are proteins produced by many bacteria that deliver toxins to neighboring bacteria, allowing the producing cell to inhibit competitors that do not make the correct antidote. Here, we show that these systems not only antagonize competitors but also mediate communication and cooperation between bacteria that produce identical toxin/antidote pairs. Antidote-containing bacteria that are targeted by toxins change their gene expression to promote biofilm formation. Leading to a more complete understanding of how these antibacterial protein systems function, this study will inform future development of therapeutics, vaccines, and decontaminants

    The effect of pre-treatment psychoeducation on eating disorder pathology among patients with anorexia nervosa and bulimia nervosa

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    Pre-treatment psychoeducation can be effective for bulimic groups, but little is known about its effect on patients with anorexia nervosa. This study investigated the impact of a pre-treatment psychoeducational intervention on outpatients with diagnoses of full or atypical anorexia nervosa (N = 54) or bulimia nervosa/atypical eating disorder at a normal weight (N = 43). Each attended a four-session psychoeducational group whilst awaiting outpatient treatment. They completed measures of eating and personality disorder pathology pre-intervention, repeating the measures of eating pathology post-intervention. Effectiveness was tested for each diagnostic group using intention-to-treat analyses. Results confirm that such psychoeducational groups reduce unhealthy eating attitudes among bulimic patients, regardless of initial levels of eating and personality pathology. In contrast, the groups were not effective for anorexia nervosa sufferers. Such groups should be considered routinely during waiting periods for bulimia nervosa treatment, but further research is needed to determine how to help anorexia nervosa patients at this stage

    Schizophrenia syndrome due to C9ORF72 mutation case report: a cautionary tale and role of hybrid brain imaging!

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    Background: Frontal variant frontotemporal dementia is a common cause of presenile dementia. A hexanucleotide expansion on chromosome 9 has recently been recognized as the most common genetic mutation cause of this illness. This sub-type tends to present psychiatrically with psychosis being a common presenting symptom before the onset of cognitive changes or brain atrophy. A few case series have been published describing the prominence of early psychotic symptoms, and lack of clear brain atrophy on clinical brain imaging imposing a challenge in reaching early accurate diagnosis. In this report, we present a case whereby the diagnosis of Schizophrenia syndrome was made and the patient was treated for years with multiple interventions for that syndrome before reaching the accurate diagnosis of Frontal variant frontotemporal dementia due to hexanucleotide expansion on chromosome 9. This diagnosis was confirmed after genetic testing and findings on a hybrid Positron Emission Tomography/Magnetic Resonance Imaging scanning. Case summary: A 60-year-old female diagnosed with schizophrenia at age 50 after presenting with delusions and hallucinations, which proved to be refractor to several lines of pharmacological and non-pharmacological interventions including electroconvulsive therapy. Patient had a history of post-partum psychosis in her 20s. She was referred to cognitive neurology due to progressive decline in function. While clinical structural brain imaging data were not adequate to support an alternative neurological diagnosis, careful inquiry elicited a history of psychotic illness followed by progressive decline in a sister. Genetic testing confirmed hexanucleotide expansion on chromosome 9 mutation. The patient was offered a state-of-the-art FD-Glucose Positron Emission Tomography/Magnetic Resonance Imaging scan available at our centre. While volumetric Magnetic Resonance Imaging scan did not show volume loss in frontotemporal areas, the hybrid scan showed regionally specific deficit in FD-Glucose Positron Emission Tomography affecting medial superior frontal, insula, inferior temporal, thalamus, and anterior cingulate cortex consistent with behavioral variant frontotemporal dementia. Conclusions: This case highlights the importance of considering Frontal variant frontotemporal dementia due to hexanucleotide expansion on chromosome 9 when facing relatively late-onset, refractory schizophrenia-like syndrome. Careful history from all available sources to elicit family history of similar presentation is very important. Genetic testing and functional brain imaging can aid in confirming the diagnosis and potentially streamlining the management of these cases

    Redefining smoking relapse as recovered social identity – secondary qualitative analysis of relapse narratives

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    Although many people in the general population manage to quit smoking, relapse is common. Theory underpinning the determinants of smoking relapse is under-developed. This article aims to specify theoretical insight into the process of relapse to smoking, to underpin effective intervention development. Secondary qualitative analysis of extended narratives of smoking relapse (n=23) were inductively coded within our conceptual framework of a socially situated narrative theoretical approach to identity. Smoking relapse is conceptualised as a situated rational response to a ‘disruption’ in individual narrative identity formation, and an attempt to recover a lost social identity. Emotional reactions to relapse, such as pleasure, but also guilt and shame, support this assertion by demonstrating the ambivalence of re-engaging in a behaviour that is situated and rational in terms of individual identity formation, yet ostracised and stigmatised by wider culture

    Lumiestrone is Photochemically Derived from Estrone and may be Released to the Environment without Detection

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    Endocrine disrupting chemicals are adversely affecting the reproductive health and metabolic status of aquatic vertebrates. Estrone is often the dominant natural estrogen in urban sewage, yet little is known about its environmental fate and biological effects. Increased use of UV-B radiation for effluent treatments, and exposure of effluents to sunlight in holding ponds led us to examine the effects of environmentally relevant levels of UV-B radiation on the photodegradation potential of estrone. Surprisingly, UV-B-mediated degradation leads to the photoproduction of lumiestrone, a little known 13α-epimer form of estrone. We show for the first time that lumiestrone possesses novel biological activity. In vivo treatment with estrone stimulated estrogen receptor (ER) α mRNA production in the male goldfish liver, whereas lumiestrone was without effect, suggesting a total loss of estrogenicity. In contrast, results from in vitro ER-dependent reporter gene assays indicate that lumiestrone showed relatively higher estrogenic potency with the zebrafish ERβ2 than zfERα, suggesting that it may act through an ERβ-selectivity. Lumiestrone also activated human ERs. Microarray analysis of male goldfish liver following in vivo treatments showed that lumiestrone respectively up- and down-regulated 20 and 69 mRNAs, which was indicative of metabolic upsets and endocrine activities. As a photodegradation product from a common estrogen of both human and farm animal origin, lumiestrone is present in sewage effluent, is produced from estrone upon exposure to natural sunlight and should be considered as a new environmental contaminant

    Randomized community-level HIV prevention intervention trial for men who drink in South African alcohol-serving venues

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    South African alcohol-serving establishments (i.e., shebeens) offer unique opportunities to reduce HIV risks among men who drink. Purpose: To test an individual- and a social structural-level HIV prevention intervention for men who drink in shebeens. Methods: Twelve matched pairs of township neighbourhoods were randomized to receive either (i) an HIV prevention intervention (guided by Social Action Theory) to reduce sexual risk and increase risk reduction communication in social networks, or (ii) an attention-matched control intervention that focused on the prevention of relationship violence. At the individual level, the interventions delivered skills building workshops focused on sexual risk reduction. At the social structural level, the intervention aimed to increase conversations about safer sex among men in the shebeens, distributed small media and implemented community educational events. Individual-level outcomes were assessed by following the workshop cohorts for 1 year (N = 984), and community-level outcomes were examined through cross-sectional community surveys conducted for 1 year in the shebeens (N = 9,678). Results: Men in the HIV prevention workshops demonstrated greater condom use, more HIV prevention-oriented conversations and greater perceptions of safer sex norms than men in the comparison workshops. Changes at the community level demonstrated significant differences in condom use, although the pattern was not consistent over time. Conclusions: Multi-level interventions that target men who drink in South African shebeens may help reduce risks for HIV and other sexually transmitted infections.Web of Scienc

    Voluntary exercise can strengthen the circadian system in aged mice

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    Consistent daily rhythms are important to healthy aging according to studies linking disrupted circadian rhythms with negative health impacts. We studied the effects of age and exercise on baseline circadian rhythms and on the circadian system's ability to respond to the perturbation induced by an 8 h advance of the light:dark (LD) cycle as a test of the system's robustness. Mice (male, mPer2luc/C57BL/6) were studied at one of two ages: 3.5 months (n = 39) and >18 months (n = 72). We examined activity records of these mice under entrained and shifted conditions as well as mPER2::LUC measures ex vivo to assess circadian function in the suprachiasmatic nuclei (SCN) and important target organs. Age was associated with reduced running wheel use, fragmentation of activity, and slowed resetting in both behavioral and molecular measures. Furthermore, we observed that for aged mice, the presence of a running wheel altered the amplitude of the spontaneous firing rate rhythm in the SCN in vitro. Following a shift of the LD cycle, both young and aged mice showed a change in rhythmicity properties of the mPER2::LUC oscillation of the SCN in vitro, and aged mice exhibited longer lasting internal desynchrony. Access to a running wheel alleviated some age-related changes in the circadian system. In an additional experiment, we replicated the effect of the running wheel, comparing behavioral and in vitro results from aged mice housed with or without a running wheel (>21 months, n = 8 per group, all examined 4 days after the shift). The impact of voluntary exercise on circadian rhythm properties in an aged animal is a novel finding and has implications for the health of older people living with environmentally induced circadian disruption
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