Ultrafast Spectroscopy with Photocurrent Detection: Watching Excitonic Optoelectronic Systems at Work.

While ultrafast spectroscopy with photocurrent detection was almost unknown before 2012, in the last 3 years, a number of research groups from different fields have independently developed ultrafast electric probe approaches and reported promising pilot studies. Here, we discuss these recent advances and provide our perspective on how photocurrent detection successfully overcomes many limitations of all-optical methods, which makes it a technique of choice when device photophysics is concerned. We also highlight compelling existing problems and research questions and suggest ways for further development, outlining the potential breakthroughs to be expected in the near future using photocurrent ultrafast optical probes.A.A.B. is currently a Royal Society University Research Fellow. A.A.B. also acknowledges a VENI grant from the NWO. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 639750). C.S. acknowledges funding from the Natural Science and Engineering Research Council of Canada, the Fonds de recherche du Québec–nature et technologies, the Canada Research Chair in Organic Semiconductor Materials, and the Université de Montréal Research Chair. C.S. and E.V. acknowledge collaboration with Sachetan Tuladhar, Michelle Vezie, Sheridan Few, Jenny Nelson, Hao Li, and Eric Bittner. Finally, C.S. and E.V. acknowledge essential discussions with Andy Marcus and Julia Widom for the implementation of the two-dimensional spectroscopy apparatus.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/acs.jpclett.5b0195

Excitonic coupling dominates the homogeneous photoluminescence excitation linewidth in semicrystalline polymeric semiconductors

We measure the homogeneous excitation linewidth of regioregular poly(3-hexylthiophene), a model semicrystalline polymeric semiconductor, by means of two-dimensional coherent photoluminescence excitation spectroscopy. At a temperature of 8\,K, we find a linewidth that is always $\gtrsim 110$\,meV full-width-at-half-maximum, which is a significant fraction of the total linewidth. It displays a spectral dependence and is minimum near the 0--0 origin peak. We interpret this spectral dependence of the homogeneous excitation linewidth within the context of a weakly coupled aggregate model.Comment: 13 pages, 4 figures, Supplementary Materia

Projeto HERA - Avaliação de risco ambiental de um ambiente estuarino contaminado: resultados do estudo epidemiológico (2011-2012)

O estuário do Sado localiza-se na costa Este de Portugal, na península de Setúbal. Estudos ambientais, realizados anteriormente neste local, identificaram várias fontes de contaminação (industrial, fontes antropogénicas não-pontuais e contaminação proveniente do rio), que em conjunto contribuem para a acumulação de sedimentos contaminados e com reconhecidos impactos sobre o sistema ecológico. A população que vive nas imediações tem atividade piscatória intensa e juntamente com atividades agrícolas, contribuem para a disponibilidade de produtos provenientes da pesca aos residentes locais. Os padrões de consumo alimentar caraterizados através de estudos etnográficos sugerem que a exposição a produtos do estuário, de produtos agrícolas e de consumo de água nas tarefas diárias constituem uma potencial via de contaminação humana. Atualmente encontra-se devidamente comprovada a associação entre a exposição a metais pesados e a existência de doenças renais e neurológicas, sendo que a maioria dos metais pesados são classificados como carcinogéneos e teratogénicos. Neste local embora haja um conjunto considerável de estudos ambientais sobre a contaminação por metais pesados e efeitos nos sistemas ecológicos, não existe nenhuma investigação que procurasse encontrar associações entre a contaminação ambiental e efeitos na saúde. Assim, de forma a ultrapassar esta lacuna de conhecimento, foi implementado no estuário do Sado um estudo integrado e multidisciplinar para avaliar o risco ambiental, incluindo ecológico e na saúde humana. O projeto HERA (Avaliação de risco ambiental de um ambiente estuarino contaminado: um estudo de caso) é financiado pela Fundação para a Ciência e Tecnologia (FCT- PTDC/SAU-ESA/100107/2008) e inclui um estudo epidemiológico que pretende caraterizar as vias de exposição aos produtos do estuário e potenciais efeitos na saúde.Fundação para a Ciência e Tecnologi

Enhancing the safety and quality of blueberry juice by thermosonication

According to consumers' newest preferences, the juice segment is expanding in the market, especially using novel high technologies for processing. Ultrasound is an up-and-coming technology increasingly being applied in the food field since it can minimize the undesirable effects of thermal processing. This study aimed to evaluate the influence of thermosonication on the inactivation kinetics of L. innocua 2030c, a non-pathogenic surrogate of L. monocytogenes, in blueberry juice. Thermal treatments were conducted as controls, and both processes' impact was assessed on some physicochemical attributes of the juice. Blueberry fruit was chosen since it is recognized as a superfruit due to its high content of health-promoting compounds. Juice samples were prepared by defrosting frozen blueberries and using a domestic centrifuge. Freshly prepared juices were inoculated with L. innocua subculture (~109 CFU/mL). Thermosonication at two amplitude levels (60 and 100%) with a pulse duration of 10 sec on and 5 sec off was applied using a sonicator probe (700 W, 20 kHz). Thermosonication and thermal treatments were performed at 45 and 55 °C until a 5-log reduction was achieved. Physicochemical parameters of the juice (pH, total soluble solids, water activity, and color) were analyzed in fresh and treated samples. All treatments/analyses were performed in triplicate. The Weibull model was successfully applied to fit L. innocua inactivation kinetic by regression analysis. The processing times needed to achieve a 5-log reduction were, in the case of thermosonicated samples, much shorter (1 and 25 min) than the heated ones (10 and 60 min), showing the effectiveness of the synergistic effect of ultrasound and mild heating compared to heat treatment alone. For thermosonication treatments, the first decimal reduction time () obtained at 55 °C was 5.13 ± 0.83 and 4.26 ± 0.36 min, respectively, for 100 and 60% amplitudes. At 45 °C, those values were reduced to 1.15 ± 0.49 and 0.51 ± 0.17 min. When thermal treatments were used, decreased to 1.18 ± 0.33 (55 HT) and 0.08 ± 0.09 min (45 HT), showing the dependence on temperature and process. Thermosonication processes were more effective in microbial inactivation and retaining quality parameters than thermal procedures, with thermosonication at 45 °C the best treatment for blueberry juice.info:eu-repo/semantics/publishedVersio

A Review of Heat Treatments on Improving the Quality and Residual Stresses of the Ti–6Al–4V Parts Produced by Additive Manufacturing

Additive manufacturing (AM) can be seen as a disruptive process that builds complex components layer upon layer. Two of its distinct technologies are Selective Laser Melting (SLM) and Electron Beam Melting (EBM), which are powder bed fusion processes that create metallic parts with the aid of a beam source. One of the most studied and manufactured superalloys in metal AM is the Ti–6Al–4V, which can be applied in the aerospace field due to its low density and high melting point, and in the biomedical area owing to its high corrosion resistance and excellent biocompatibility when in contact with tissues or bones of the human body. The research novelty of this work is the aggregation of all kinds of data from the last 20 years of investigation about Ti–6Al–4V parts manufactured via SLM and EBM, namely information related to residual stresses (RS), as well as the influence played by different heat treatments in reducing porosity and increasing mechanical properties. Throughout the report, it can be seen that the expected microstructure of the Ti–6Al–4V alloy is different in both manufacturing processes, mainly due to the distinct cooling rates. However, heat treatments can modify the microstructure, reduce RS, and increase the ductility, fatigue life, and hardness of the components. Furthermore, distinct post-treatments can induce compressive RS on the part’s surface, consequently enhancing the fatigue lifeinfo:eu-repo/semantics/publishedVersio

Relationship between comprehension levels and reading strategies used in a therapeutic program by deaf individuals who communicate through sign language

OBJETIVO: Determinar as mudanças referentes às estratégias de aprendizagem nos níveis de compreensão de leitura durante um programa de intervenção fonoaudiológica direcionado aos surdos sinalizadores. MÉTODOS: Participaram cinco estudantes surdos, com idades entre dez anos e 15 anos, cuja língua preferencial para comunicação era a Língua Brasileira de Sinais. Todos frequentaram um programa de intervenção fonoaudiológica fundamentada na técnica de scaffolding (andaime). As variáveis consistiram dos desempenhos das avaliações individuais do nível de compreensão de leitura e das estratégias utilizadas para esta compreensão, antes de iniciar o programa e ao término do mesmo. RESULTADOS: Ao término do programa de intervenção, mais estudantes surdos utilizaram estratégias de elaboração (p=0,197) e menos estudantes utilizaram estratégias de monitoramento (p=0,197). Houve mudança significativa quanto à pontuação do nível de decodificação (p=0,109) e tendência à significância no nível de compreensão literal (p=0,197), com aumento da pontuação. Verificou-se significância somente entre a utilização da estratégia de elaboração e os dois momentos da avaliação (inicial e final) (p=0,059). CONCLUSÃO: O programa de intervenção baseado na técnica de scaffolding propiciou que estudantes surdos sinalizadores utilizassem mais estratégias de elaboração e menos de monitoramento; consequentemente, uma tendência para a passagem do nível de decodificação para o nível de compreensão literal do texto.PURPOSE: To establish changes in learning strategies at reading comprehension levels during a speech-language intervention program for deaf individuals who use sign language. METHODS: Five deaf students, with ages between ten and 15 years, whose preferential modality of communication was the Brazilian Sign Language, participated in the study. All subjects were participating in a speech-language intervention program based on the scaffolding technique. The variables were both the performance of individual assessments of reading comprehension level and strategies used for this purpose, before and after the program. RESULTS: At the end of the intervention program, there were more students using elaboration strategies (p=0.197), and less students using monitoring strategies (p=0.197). There was a significant change in the score of the decoding level (p=0.109), and a tendency to literal comprehension (p=0.197), with increasing scores. Significance was found only between the use of elaboration strategy and the two assessment moments (at the beginning and at the end of the program) (p=0.059). CONCLUSION: The intervention program based on scaffolding technique, enabled deaf students who communicate through sign language to use more elaboration strategies and less monitoring strategies. Therefore, there was a tendency to change from decoding level to literal reading comprehension level.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Tabaco e Gravidez

O consumo de tabaco na gravidez tem sido associado a riscos de parto prematuro e baixo peso do recém-nascido. Esta questão torna-se premente tendo em conta estudos recentes, realizados em Portugal, que evidenciam um aumento do consumo do tabaco em mulheres do grupo etário 15-44. Este trabalho visou estudar a “Prevalência do consumo de tabaco nas grávidas” através de um estudo-satélite realizado no âmbito da rede "Médicos-Sentinela"