Density Gradients, Cellular Structure and Thermal Conductivity of High-Density Polyethylene Foams by Different Amounts of Chemical Blowing Agent.

LDPE (low-density polyethylene) foams were prepared using the improved compression moulding technique (ICM) with relative densities ranging from 0.3 to 0.7 and with different levels of chemical blowing agents (from 1% to 20%). The density gradients, cellular structure and thermal conductivity of the foams were characterized. The density and amount of CBA used were found to have a significant effect on the cellular structure both at the mesoscale (density gradients) and at the microscale (different cell sizes and cell densities). In addition, the thermal conductivity of the samples is very sensitive to the local structure where the heat flux is located. The technique used to measure this property, the Transient Plane Source method (TPS), makes it possible to detect the presence of density gradients. A simple method for determining these gradients based on thermal conductivity data was developed.

Medo de cair em idosos classificados como vulneráveis de um centro de referência à atenção da saúde do idoso / Fear of falling among elderly people classified as vulnerable in a referral center for elderly health care

Objetivo: Correlacionar o medo de cair com a vulnerabilidade em idosos. Método: A vulnerabilidade foi avaliada por meio da Pesquisa sobre Idosos Vulneráveis (VES-13) e o medo de cair pela Escala de Eficácia de Quedas - Internacional ­ Brasileira (FES-I-BR), participaram idosos de ambos os sexos e idade (60-85 anos), foram excluídos voluntários com limitações cognitivas e os que não participavam do grupo de convivência. Foram aplicado os testes de Kolmogorov-Smirnov, de Mann-Whitney, de Spearman, de regressão logística binária e para análise de sensibilidade e especificidade da FES-I-BR, empregou-se a curva da característica do operador receptor (ROC), a análise foi realizada em 95% nível de confiança e p<0,05 foi adotado. Resultados: Entre os n= 123 idosos, foi observado que (33,3%) são vulneráveis, n= 120 (97,6%) apresentaram alguma preocupação em cair. Entre as atividades analisadas na FES-I-BR, 21,1% estão extremamente preocupados em cair ao andar em superfícies escorregadias e foi observada uma correlação positiva e significativa entre a pontuação do VES-13 com a pontuação da FES-I-BR, a FES-I-BR foi um previsor significativo para a vulnerabilidade. A FES-I-BR de forma aceitável mostrou-se capaz de discriminar o medo de cair de vulneráveis de não vulneráveis em uma área de 0,656 (p<0,005), sensibilidade de 53,7% e especificidade de 69,5%. Conclusão: O medo de cair está correlacionado com a vulnerabilidade, os idosos vulneráveis apresentaram mais medo de cair, o medo de cair é fator preditor de vulnerabilidade e a FES-I-BR foi capaz de discriminar o medo de cair de idosos vulneráveis e não vulneráveis

Objective: Was to correlate the fear of falling with vulnerability in the elderly. Method: Vulnerability was assessed using the Vulnerable Elderly Survey (VES-13) and the fear of falling using the Falls Efficacy Scale - International - Brazilian (FES-I-BR), elderly people of both sexes and age (60- 85 years old), volunteers with cognitive limitations and those who did not participate in the coexistence group were excluded. The Kolmogorov-Smirnov, Mann-Whitney, Spearman, binary logistic regression tests were applied and for the sensitivity and specificity analysis of the FES-I-BR, the Receiver Operator Characteristic Curve (ROC) was used, analysis was performed at 95% confidence level and p <0.05 was adopted. Results: Among the n = 123 elderly, it was observed that (33.3%) are vulnerable, n = 120 (97.6%) had some concern about falling. Among the activities analyzed at FES-I-BR, 21.1% are extremely concerned about falling when walking on slippery surfaces and a positive and significant correlation was observed between the VES-13 score and the FES-I-BR score, FES-I-BR was a significant predictor for the vulnerability. In the present study, the FES-I-BR in an acceptable way proved to be able to discriminate the fear of falling from vulnerable to non-vulnerable in an area of 0.656 (p <0.005), sensitivity of 53.7% and specificity of 69, 5%. Conclusion: Fear of falling is correlated with vulnerability, vulnerable elderly people were more afraid of falling, fear of falling is a predictor of vulnerability and FES-I-BR was able to discriminate between the fear of falling of vulnerable and non-vulnerable elderly people