Raman spectroscopy as a versatile tool for studying the properties of graphene.

Raman spectroscopy is an integral part of graphene research. It is used to determine the number and orientation of layers, the quality and types of edge, and the effects of perturbations, such as electric and magnetic fields, strain, doping, disorder and functional groups. This, in turn, provides insight into all sp(2)-bonded carbon allotropes, because graphene is their fundamental building block. Here we review the state of the art, future directions and open questions in Raman spectroscopy of graphene. We describe essential physical processes whose importance has only recently been recognized, such as the various types of resonance at play, and the role of quantum interference. We update all basic concepts and notations, and propose a terminology that is able to describe any result in literature. We finally highlight the potential of Raman spectroscopy for layered materials other than graphene

Prevalência de transtornos mentais em área urbana no norte de Minas Gerais, Brasil Prevalence of mental disorders in an urban area in Brazil

OBJETIVO: Detectar a prevalência de transtornos mentais em idosos residentes em área urbana. MÉTODOS: Uma amostra de 327 idosos (60 anos de idade ou mais) residentes na cidade de Montes Claros, no norte de Minas Gerais, foi selecionada por amostragem probabilística, em estratos múltiplos, dentro de estrato homogêneo, sendo a unidade amostral o domicílio. Os transtornos mentais foram aferidos por meio de um questionário de rastreamento psicogeriátrico (QRP). Utilizou-se análise univariada usando o qui-quadrado e análise multivariada de regressão logística. RESULTADOS: A prevalência estimada de transtornos mentais foi 29,3%, associada com sexo feminino, número de doença, capacidade funcional e local de residência (favela/não favela). CONCLUSÕES: Comparando com outros estudos comunitários, a prevalência de distúrbios mentais entre os idosos na área urbana foi alta e está associada com múltiplas doenças, incapacidade e pobreza. É uma realidade preocupante pelo de seu impacto sobre a qualidade de vida relativa à saúde da população e sobre os serviços de saúde nas próximas décadas.<br>OBJECTIVE: To detect the prevalence of mental disorders among the elderly residents of an urban area. METHODS: A sample of 327 elderly residents (60 years and older) of the city of Montes Claros, in northern Minas Gerais, was selected by means of probabilistic sampling, in multiple strata, within a homogeneous stratum. The sample unit was the home. Mental disorders were determined by means of the Short Psychiatric Evaluation Schedule (SPES). Univariate analysis was done via the chi-squared test and multivariate analysis via logistical regression. RESULTS: The estimated prevalence of mental disorders was 29.3%. Their presence was associated with female sex, number of illnesses, functional capacity and place of residence (shantytown/non-shantytown). CONCLUSIONS: Comparing the results with other community studies, the prevalence of mental disorders among the elderly in the urban area of Montes Claros was high and was associated with multiple illnesses, incapacity and poverty. This reality is a matter for concern because of its impact on quality of life relating to this population's health, and on healthcare services over the next few decades

O uso dos índices de impedância da artéria esplênica na avaliação da hipertensão portal Utilization of splenic impedance indices in the evaluation of portal hypertension

OBJETIVO: Estudar os índices de impedância - índices de resistência (IR) e pulsatilidade (IP) - da artéria esplênica em pacientes com hepatopatia crônica. MATERIAIS E MÉTODOS: Foram estudados, prospectivamente, 42 pacientes com cirrose hepática e 21 pacientes com hepatite crônica. RESULTADOS: Foi observado que, nos pacientes com cirrose, ambos os índices estiveram elevados (IR = 0,63 &plusmn; 0,08 e IP = 1,02 &plusmn; 0,22) em comparação com os pacientes com hepatite crônica (IR = 0,58 &plusmn; 0,06 e IP = 0,89 &plusmn; 0,15) e os indivíduos do grupo controle (IR = 0,57 &plusmn; 0,04 e IP = 0,87 &plusmn; 0,11). Os cirróticos com evidência de circulação colateral à ultra-sonografia apresentaram, no entanto, menores índices de resistência (IR = 0,60 &plusmn; 0,08) em comparação com os cirróticos sem circulação colateral (IR = 0,65 &plusmn; 0,07), possivelmente devido ao shunt portossistêmico provocado pelos vasos colaterais. Não houve diferença significativa dos índices entre pacientes com e sem varizes esofagianas. CONCLUSÃO: O trabalho demonstrou que os índices de impedância da artéria esplênica podem ser úteis na avaliação de pacientes com hepatopatia crônica e hipertensão portal, contribuindo com dados adicionais à ultra-sonografia com eco-Doppler colorido.<br>OBJECTIVE: The aim of the present study was to analyze splenic impedance indices - resistive index (RI) and pulsatility index (PI) - in patients with chronic liver disease. MATERIALS AND METHODS: Forty-two patients with hepatic cirrhosis and 21 patients with chronic hepatitis were prospectively evaluated. RESULTS: In patients with cirrhosis, both indices were higher (RI = 0.63 &plusmn; 0.08; PI = 1.02 &plusmn; 0.22) than those found in patients with chronic hepatitis (RI = 0.58 &plusmn; 0.06; PI = 0.89 &plusmn; 0.15) and in the control group individuals (RI = 0.57 &plusmn; 0.04; PI = 0.87 &plusmn; 0.11). However, cirrhotic patients with evidence of collateral circulation at ultrasound presented lower resistive indices (RI = 0.60 &plusmn; 0.08) compared with those without collateral circulation (RI = 0.65 &plusmn; 0.07), possibly due to the portosystemic shunt caused by collateral vessels. There was no significant difference of indices between patients with and without esophageal varices. CONCLUSION: The present study has demonstrated that splenic artery impedance indices may be useful in the evaluation of patients affected by chronic liver disease and portal hypertension, contributing with additional data at color Doppler ultrasound

Morphometric brain changes during aging: Results from a Brazilian necropsy sample

The present study aimed to establish the morphometric brain changes during aging in a necropsy series from Brazil and determine whether sexual dimorphisms interfere in these changes. Methods:A cross-sectional study was conducted at the São Paulo Autopsy Service in Brazil where, after informed consent, data was gathered from next of kin interview with reference to clinical status prior to death. Brain weight, volume and density measurements were taken and then adjusted for head circumference. Descriptive statistics and tests of hypothesis and correlations were applied, considering a p-value of 0.05. Results:414 subjects, mostly men (60.4%), with a mean age of 67.1 years, were included. The mean brain weight of the sample was 1219.2g±140.9and mean volume was 1217mL±152.3. The mean brain density of the sample was 1.0g/mL±0.09. Values differed between males and females in terms of weight and volume. Brain weight decreased during aging by about 45g per decade (r= -0.300; p&lt;0.01) and volume by about 43mL (r= -0.278; p&lt;0.00). Mean density of the sample was 1.0 g/mL in both genders. Conclusions:Brain weight and volume (with or without corrections) decreased during aging, and these reductions were more pronounced in women. Density remained unchanged for both genders. Further studies are needed to investigate factors associated to these reductions