Coexistence of ferro- and antiferromagnetic order in Mn-doped Ni2_2MnGa

Ni-Mn-Ga is interesting as a prototype of a magnetic shape-memory alloy showing large magnetic field induced strains. We present here results for the magnetic ordering of Mn-rich Ni-Mn-Ga alloys based on both experiments and theory. Experimental trends for the composition dependence of the magnetization are measured by a vibrating sample magnetometer (VSM) in magnetic fields of up to several tesla and at low temperatures. The saturation magnetization has a maximum near the stoichiometric composition and it decreases with increasing Mn content. This unexpected behaviour is interpreted via first-principles calculations within the density-functional theory. We show that extra Mn atoms are antiferromagnetically aligned to the other moments, which explains the dependence of the magnetization on composition. In addition, the effect of Mn doping on the stabilization of the structural phases and on the magnetic anisotropy energy is demonstrated.Comment: 4 pages, 3 figure

Self-harm in young people with perinatal HIV and HIV negative young people in England: cross sectional analysis.

BACKGROUND: Self-harm in adolescents is of growing concern internationally but limited evidence exists on the prevalence of self-harm in those living with HIV, who may be at higher risk of poor mental health outcomes. Therefore our aim was to determine the prevalence and predictors of self-harm among young people with perinatally-acquired HIV (PHIV) and HIV negative (with sibling or mother living with HIV) young people living in England. METHODS: 303 PHIV and 100 HIV negative young people (aged 12-23 years) participating in the Adolescents and Adults Living with Perinatal HIV cohort study completed an anonymous self-harm questionnaire, as well as a number of standardised mental-health assessments. Logistic regression investigated predictors of self-harm. RESULTS: The median age was 16.7 years in both groups, and 40.9% of the PHIV and 31.0% of the HIV negative groups were male. In total 13.9% (56/403) reported having ever self-harmed, with no difference by HIV status (p = 0.089). Multivariable predictors of self-harm were female sex (adjusted odds ratio (AOR) 5.3, (95% confidence interval 1.9, 14.1), p = 0.001), lower self-esteem (AOR 0.9 (0.8, 0.9) per 1 point increase, p < 0.001) and having ever used alcohol (AOR 3.8 (1.8, 7.8), p < 0.001). Self-esteem z-scores for both PHIV and HIV negative participants were 1.9 standard deviations below the mean for population norms. CONCLUSIONS: Self-harm is common among PHIV and HIV negative adolescents in England. Reassuringly however, they do not appear to be at an increased risk compared to the general adolescent population (15-19% lifetime prevalence). The low level of self-esteem (compared to available normative data) in both groups is worrying and warrants further attention

Congenital Hydrocephalus and Abnormal Subcommissural Organ Development in Sox3 Transgenic Mice

Congenital hydrocephalus (CH) is a life-threatening medical condition in which excessive accumulation of CSF leads to ventricular expansion and increased intracranial pressure. Stenosis (blockage) of the Sylvian aqueduct (Aq; the narrow passageway that connects the third and fourth ventricles) is a common form of CH in humans, although the genetic basis of this condition is unknown. Mouse models of CH indicate that Aq stenosis is associated with abnormal development of the subcommmissural organ (SCO) a small secretory organ located at the dorsal midline of the caudal diencephalon. Glycoproteins secreted by the SCO generate Reissner's fibre (RF), a thread-like structure that descends into the Aq and is thought to maintain its patency. However, despite the importance of SCO function in CSF homeostasis, the genetic program that controls SCO development is poorly understood. Here, we show that the X-linked transcription factor SOX3 is expressed in the murine SCO throughout its development and in the mature organ. Importantly, overexpression of Sox3 in the dorsal diencephalic midline of transgenic mice induces CH via a dose-dependent mechanism. Histological, gene expression and cellular proliferation studies indicate that Sox3 overexpression disrupts the development of the SCO primordium through inhibition of diencephalic roof plate identity without inducing programmed cell death. This study provides further evidence that SCO function is essential for the prevention of hydrocephalus and indicates that overexpression of Sox3 in the dorsal midline alters progenitor cell differentiation in a dose-dependent manner

Self-help interventions for depressive disorders and depressive symptoms: a systematic review

<p>Abstract</p> <p>Background</p> <p>Research suggests that depressive disorders exist on a continuum, with subthreshold symptoms causing considerable population burden and increasing individual risk of developing major depressive disorder. An alternative strategy to professional treatment of subthreshold depression is population promotion of effective self-help interventions that can be easily applied by an individual without professional guidance. The evidence for self-help interventions for depressive symptoms is reviewed in the present work, with the aim of identifying promising interventions that could inform future health promotion campaigns or stimulate further research.</p> <p>Methods</p> <p>A literature search for randomised controlled trials investigating self-help interventions for depressive disorders or depressive symptoms was performed using PubMed, PsycINFO and the Cochrane Database of Systematic Reviews. Reference lists and citations of included studies were also checked. Studies were grouped into those involving participants with depressive disorders or a high level of depressive symptoms, or non-clinically depressed participants not selected for depression. A number of exclusion criteria were applied, including trials with small sample sizes and where the intervention was adjunctive to antidepressants or psychotherapy.</p> <p>Results</p> <p>The majority of interventions searched had no relevant evidence to review. Of the 38 interventions reviewed, the ones with the best evidence of efficacy in depressive disorders were S-adenosylmethionine, St John's wort, bibliotherapy, computerised interventions, distraction, relaxation training, exercise, pleasant activities, sleep deprivation, and light therapy. A number of other interventions showed promise but had received less research attention. Research in non-clinical samples indicated immediate beneficial effects on depressed mood for distraction, exercise, humour, music, negative air ionisation, and singing; while potential for helpful longer-term effects was found for autogenic training, light therapy, omega 3 fatty acids, pets, and prayer. Many of the trials were poor quality and may not generalise to self-help without professional guidance.</p> <p>Conclusion</p> <p>A number of self-help interventions have promising evidence for reducing subthreshold depressive symptoms. Other forms of evidence such as expert consensus may be more appropriate for interventions that are not feasible to evaluate in randomised controlled trials. There needs to be evaluation of whether promotion to the public of effective self-help strategies for subthreshold depressive symptoms could delay or prevent onset of depressive illness, reduce functional impairment, and prevent progression to other undesirable outcomes such as harmful use of substances.</p

COMPATIBILITY OF UNSUPPORTED PYROLYTIC-CARBON COATED URANIUM DICARBIDE PARTICLES WITH WATER VAPOR

Five batches of pyrolytic-carbon-coated uranium carbide particles were exposed to partial pressures of water vapor ranging from 20 to 635 mm Hg at temperatures of 700 to 1100 deg C. All batches of coated particles had laminar type of coating and contained cores consisting principally of uranium dicarbide. The rate of reaction of the pyrolytic-carbon coatings with water vapor was determined from weight losses. The extent of failure of the coatings during exposure was established by microscopic examination and leaching of the particles with 8M HNO/sub 3/. Differences in the protectiveness of coatings present on the various batches of particles are attributable, at least in part, to two types of attack by water vapor, a localized or pitting type and a more general type. Rapid failure of the coatings was indicated at 1100 deg C. The coatings on some batches of particles remained protective at temperatures of 800 to 1000 deg C. (auth