Electron irradiation induced nanocrystal formation in Cu-borosilicate glass

Nanoscale writing of Cu nanoparticles in glasses is introduced using focused electron irradiation by transmission electron microscopy. Two types of copper borosilicate glasses, one with high and another with low Cu loading, have been tested at energies of 200–300 keV, and formation of Cu nanoparticles in a variety of shapes and sizes using different irradiation conditions is achieved. Electron energy loss spectroscopy analysis, combined with high-resolution transmission electron microscopy imaging, confirmed the irradiation-induced precipitated nanoparticles as metallic, while furnace annealing of the glass triggered dendrite-shaped particles of copper oxide. Unusual patterns of nanoparticle rings and chains under focused electron beam irradiation are also presented. Conclusively, electron beam patterning of Cu-loaded glasses is a promising alternative route to well-established femtosecond laser photoreduction of Cu ions in glass

Social support and common mental disorder among medical students

INTRODUÇÃO:Diferentes formas de sofrimento psíquico têm sido identificadas em estudantes da área da saúde, em especial no curso de Medicina.OBJETIVO:Estimar a prevalência de sofrimento psíquico entre estudantes de Medicina em uma faculdade no Sudeste do Brasil e avaliar sua associação com apoio social.MÉTODO:Trata-se de um estudo transversal. Foram aplicados questionários para alunos do 1º ao 6º ano do curso de Medicina da Universidade Estadual Paulista Júlio de Mesquita Filho, investigando-se características demográficas relacionadas ao curso e à adaptação à cidade. Sofrimento psíquico foi investigado na forma de Transtorno Mental Comum (TMC), avaliado por meio do Self-Reporting Questionnaire (SRQ-20). Apoio social foi avaliado com a Escala de Apoio Social (EAS). As associações entre o desfecho e as variáveis explanatórias foram analisadas por meio do teste do χ2 e, na análise multivariada, por meio da Regressão Logística, com p < 0,05.RESULTADOS:A taxa de resposta foi de 80,7%, não havendo diferença estatística entre a mostra e a população-alvo no que diz respeito ao gênero (p = 0,78). A média de idade foi de 22 anos (desvio padrão - DP = 2,2) com predomínio de mulheres (58,2%) e estudantes que vivem com amigos (62%). A prevalência de TMC foi de 44,9% (IC95% 40,2 - 49,6). Após a análise multivariada, mantiveram-se associados a TMC: sentir-se rejeitado no último ano (p < 0,001), ter pensado ou pensar em abandonar o curso (p < 0,001) e interação, avaliada pela EAS (p = 0,002).CONCLUSÕES:A prevalência de TMC entre estudantes de Medicina mostrou-se elevada, identificando-se o apoio social insuficiente como fator de risco. Esses achados sugerem que intervenções voltadas para propiciar melhores condições de interação social entre estudantes poderiam ser benéficas, diminuindo a prevalência de TMC nesse grupo.INTRODUCTION:Different kinds of psychological distress have been identified for students in the health field, especially in the medical school.OBJECTIVE:To estimate the prevalence of mental suffering among medical students in the Southeastern Brazil and asses its association with social support.METHODS:It is a cross-sectional study. Structured questionnaires were applied for students from the 1st up to the 6th years of the medical school of Universidade Estadual Paulista Júlio de Mesquita Filho, assessing demographic variables related to aspects of graduation and adaptation to the city. Psychological suffering was defined as a common mental disorder (CMD) assessed by the Self Reporting Questionnaire (SRQ-20). Social support was assessed by the social support scale of the Medical Outcomes Study (MOS). The association between the outcome and explanatory variables was assessed by the χ2 test and Logistic Regression, for the multivariate analyses, using p < 0.05.RESULTS:The response rate was of 80.7%, with no differences between sample and the population regarding gender (p = 0.78). The average age was 22 years old (standard deviation - SD = 2.2), mainly women (58.2%) and students who were living with friends (62%). The prevalence of CMD was 44.9% (95%CI 40.2 - 49.6). After the multivariate analyses, the explanatory variables that were associated with CMD were: feeling rejected in the past year (p < 0.001), thinking about leaving medical school (p < 0.001) and interaction in the MOS scale (p = 0.002).CONCLUSIONS:The prevalence of CMD among medical students was high and insufficient social support was an important risk factor. Our findings suggest that interventions to improve social interaction among those students could be beneficial, decreasing the prevalence of CMD in this group.Hospital das Clínicas de Ribeirão PretoUniversidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Medicina de Botucatu Departamento de Neurologia, Psicologia e PsiquiatriaUniversidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Medicina de Botucatu Departamento de Neurologia, Psicologia e Psiquiatri

Ultrafast-nonlinear ultraviolet pulse modulation in an AlInGaN polariton waveguide operating up to room temperature

Ultrafast nonlinear photonics enables a host of applications in advanced on-chip spectroscopy and information processing. These rely on a strong intensity dependent (nonlinear) refractive index capable of modulating optical pulses on sub-picosecond timescales and on length scales suitable for integrated photonics. Currently there is no platform that can provide this for the UV spectral range where broadband spectra generated by nonlinear modulation can pave the way to new on-chip ultrafast (bio-) chemical spectroscopy devices. We introduce an AlInGaN waveguide supporting highly nonlinear UV hybrid light-matter states (exciton-polaritons) up to room temperature. We experimentally demonstrate ultrafast nonlinear spectral broadening of UV pulses in a compact 100 micrometer long device and measure a nonlinearity 1000 times that in common UV nonlinear materials and comparable to non-UV polariton devices. Our demonstration, utilising the mature AlInGaN platform, promises to underpin a new generation of integrated UV nonlinear light sources for advanced spectroscopy and measurement