Persistent organic pollutant levels in human visceral and subcutaneous adipose tissue in obese individuals - Depot differences and dysmetabolism implications

Background: The role of persistent organic pollutants (POPs) with endocrine disrupting activity in the aetiology of obesity and other metabolic dysfunctions has been recently highlighted. Adipose tissue (AT) is a common site of POPs accumulation where they can induce adverse effects on human health. Objectives: To evaluate the presence of POPs in human visceral (vAT) and subcutaneous (scAT) adipose tissue in a sample of Portuguese obese patients that underwent bariatric surgery, and assess their putative association with metabolic disruption preoperatively, as well as with subsequent body mass index (BMI) reduction. Methods: AT samples (n=189) from obese patients (BMI ≥35) were collected and the levels of 13 POPs were determined by gas chromatography with electron-capture detection (GC-ECD). Anthropometric and biochemical data were collected at the time of surgery. BMI variation was evaluated after 12 months and adipocyte size was measured in AT samples. Results: Our data confirm that POPs are pervasive in this obese population (96.3% of detection on both tissues), their abundance increasing with age (RS=0.310, p<0.01) and duration of obesity (RS=0.170, p<0.05). We observed a difference in AT depot POPs storage capability, with higher levels of ΣPOPs in vAT (213.9±204.2 compared to 155.1±147.4 ng/g of fat, p<0.001), extremely relevant when evaluating their metabolic impact. Furthermore, there was a positive correlation between POP levels and the presence of metabolic syndrome components, namely dysglycaemia and hypertension, and more importantly with cardiovascular risk (RS=0.277, p<0.01), with relevance for vAT (RS=0.315, p<0.01). Finally, we observed an interesting relation of higher POP levels with lower weight loss in older patients. Conclusion: Our sample of obese subjects allowed us to highlight the importance of POPs stored in AT on the development of metabolic dysfunction in a context of obesity, shifting the focus to their metabolic effects and not only for their recognition as environmental obesogens.

Relatório de estágio: intervenção em fisioterapia na sindrome da cirurgia lombar falhada

Introdução: A síndrome da cirurgia lombar falhada (SCLF) caracteriza-se pela persistência ou recidiva da dor ou aparecimento de novos sintomas após discectomia, descompressão de canal estreito ou artrodese lombares. Objectivos: O objectivo deste estudo foi descrever a abordagem em fisioterapia de um caso com Síndrome da Cirurgia Lombar Falhada e avaliar os seus efeitos na funcionalidade e sintomatologia dolorosa neste indivíduo. Metodologia: A amostra foi constituída por um sujeito com 41 anos, trabalhador da construção civil, apresentando dor lombar com irradiação para o membro inferior, após ter sido submetido a discectomia lombar e artrodese, que realizou sessões de fisioterapia convencional antes e depois da cirurgia, e que apresentava sinais compatíveis com compressão radicular. A intensidade da dor foi medida através da escala visual analógica (EVA), as amplitudes com o goniómetro universal, a funcionalidade foi avaliada utilizando o Questionário de Incapacidade Roland-Morris (RMDQ), o estado psicológico foi avaliado através da “Escala de Desânimo Associado à Dor” e do “Inventário de Convicções e Percepções Relacionadas com a Dor”. Resultados: A dor era inicialmente em média de 5,5/10 EVA, sendo de 3,4/10 EVA no final do tratamento. Quanto à funcionalidade (RMDQ) esta variou de 14/24 no início para 17/24 no final. De uma forma geral, após a aplicação de técnicas para diminuir a tensão do piriforme, técnicas neuurodinâmicas e um programa de exercícios para melhoria do controlo motor, o paciente apresentou alívio das queixas de dor na nádega esquerda e anca, aumento da amplitude de rotação medial da coxo-femoral, ausência das parestesias na face plantar do pé esquerdo e melhoria das queixas de dor na face anterior e lateral da coxa. Verificamos que houve diminuição dos índices de dor e melhorias dos níveis de funcionalidade. Conclusão: Neste estudo de caso, foi salientado o processo de raciocínio clínico desenvolvido pelo fisioterapeuta: a interpretação dos dados da história e levantamento das primeiras hipóteses e a realização dos testes no exame objectivo, permitiram estabelecer um diagnóstico funcional e elaborar um plano de intervenção através do qual o utente recuperou parcialmente a sua funcionalidade e diminuiu os seus índices de dor.

Hopping conduction and persistent photoconductivity in Cu2ZnSnS4 thin films

The temperature dependence of electrical conductivity and the photoconductivity of polycrystalline Cu2ZnSnS4 were investigated. It was found that at high temperatures the electrical conductivity was dominated by band conduction and nearest-neighbour hopping. However, at lower temperatures, both Mott variable-range hopping (VRH) and Efros–Shklovskii VRH were observed. The analysis of electrical transport showed high doping levels and a large compensation ratio, demonstrating large degree of disorder in Cu2ZnSnS4. Photoconductivity studies showed the presence of a persistent photoconductivity effect with decay time increasing with temperature, due to the presence of random local potential fluctuations in the Cu2ZnSnS4 thin film. These random local potential fluctuations cannot be attributed to grain boundaries but to the large disorder in Cu2ZnSnS4.

Anomalous persistent photoconductivity in Cu2ZnSnS4 thin films and solar cells

A persistent photoconductivity effect (PPC) has been investigated in Cu2ZnSnS4 thin films and solar cells as a function of temperature. An anomalous increase of the PPC decay time with temperature was observed in all samples. The PPC decay time activation energy was found to increase when temperature rises above a crossover value, and also to grow with the increase of the sulfurization temperature and pressure. Both the anomalous behavior of the PPC decay time and the existence of two different activation energies are explained in terms of local potential fluctuations in the band edges of CZTS.