Processing temperature is highlighted as a convenient means of controlling the optical and charge transport properties of solution processed electron transport layers (ETLs) in inverted polymer solar ...cells. Using the well‐studied active layer – poly(3‐hexylthiophene‐2,5‐diyl):indene‐C60 bisadduct – the influence of ETL processing temperatures from 25 to 450 °C is shown, reporting the role of crystallinity, structure, charge transport, and Fermi level (EF) on numerous device performance characteristics. It has been determined that an exceptionally low temperature processed ETL (110 °C) increases device power conversion efficiency by a factor greater than 50% compared with a high temperature (450 °C) processed ETL. Modulations in device series and shunt resistance, induced by changes in the ETL transport properties, are observed in parallel to significant changes in device open circuit voltage attributed to changes on the EF of the ETLs. This work highlights the importance of interlayer control in multilayer photovoltaic devices and presents a convenient material compatible with future flexible and roll‐to‐roll processes.
Novel ZnO‐based electron transport layers (ETLs) are incorporated into inverted organic photovoltaics with a processing temperature of only 110 °C identified as optimum for enhanced device performance. ETL composition and microstructure are evaluated over the temperature range 25–450 °C. Performance enhancements are attributed to improvements in open‐circuit voltage, originating from shifts in the ETL Fermi level and reduced leakage current.
Purpose – This paper aims to analyse the volatility of the fixed income market from 11 countries (Brazil, Russia, India, China, South Africa, Argentina, Chile, Mexico, USA, Germany and Japan) from ...January 2000 to December 2011 by examining the interbank interest rates from each market. Design/methodology/approach – To the volatility of interest rates returns, the study used models of auto-regressive conditional heteroscedasticity, autoregressive conditional heteroscedasticity (ARCH), generalized autoregressive conditional heteroscedasticity (GARCH), exponential generalized autoregressive conditional heteroscedasticity (EGARCH), threshold generalized autoregressive conditional heteroscedasticity (TGARCH) and periodic generalized autoregressive conditional heteroscedasticity (PGARCH), and a combination of these with autoregressive integrated moving average (ARIMA) models, checking which of these processes were more efficient in capturing volatility of interest rates of each of the sample countries. Findings – The results suggest that for most markets, studied volatility is best modelled by asymmetric GARCH processes – in this case the EGARCH – demonstrating that bad news leads to a higher increase in the volatility of these markets than good news. In addition, the causes of increased volatility seem to be more associated with events occurring internally in each country, as changes in macroeconomic policies, than the overall external events. Originality/value – It is expected that this study has contributed to a better understanding of the volatility of interest rates and the main factors affecting this market.
In article number 1500204, Aram Amassian and co‐workers demonstrate the preparation of highly efficient polymer solar cells on rigid glass and flexible polyethylene terephthalate (PET) substrates ...using a facile and low‐temperature solution processed Al:ZnO (AZO) nanocrystalline buffer layer prepared in a single step, without requiring any surface passivation. Efficiencies of 10.2% and 8.2% are reported for glass and plastic substrates, respectively.
A charge‐carrier density dependent mobility has been predicted for amorphous, glassy energetically disordered semiconducting polymers, which would have considerable impact on their performance in ...devices. However, previous observations of a density dependent mobility are complicated by the polycrystalline materials studied. Here charge transport in field‐effect transistors and diodes of two amorphous, glassy fluorene‐triarylamine copolymers is investigated, and the results explored in terms of a charge‐carrier density dependent mobility model. The nondispersive nature of the time‐of‐flight (TOF) transients and analysis of dark injection transient results and transistor transfer characteristics indicate a charge‐carrier density independent mobility in both the low‐density diode and the high‐density transistor regimes. The mobility values for optimized transistors are in good agreement with the TOF values at the same field, and both have the same temperature dependency. The measured transistor mobility falls two to three orders of magnitude below that predicted from the charge‐carrier density dependent model, and does not follow the expected power‐law relationship. The experimental results for these two amorphous polymers are therefore consistent with a charge‐carrier density independent mobility, and this is discussed in terms of polaron‐dominated hopping and interchain correlated disorder.
Charge transport in diodes and transistors of two amorphous glassy fluorene‐triarylamine copolymers is found to be consistent with a charge‐carrier density independent mobility. This is in contradiction to many theoretical models, which predict a charge‐carrier density dependent mobility for such energetically disordered organic semiconductors. This could indicate that interchain correlations can smooth out the energy landscape in amorphous conjugated polymers.
Abstract Recent studies have demonstrated that, in Brazil and South America, strains of Toxoplasma gondii are often genotypically and biologically different from those found in countries on other ...continents. The objective of this study was to genotypically characterize T. gondii isolates from naturally infected sheep in herds in the southern region of the state of Rio Grande do Sul, Brazil, by means of the polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP). Five T. gondii isolates obtained from sheep in five municipalities in the state of Rio Grande do Sul were used. Application of multilocus PCR-RFLP multilocus using 12 genetic markers (SAG1, 5′3′ SAG2, alt. SAG2, SAG3, BTUB, c22-8, c29-2, GRA6, L358, PK1, APICO and CS3) revealed four different genotypes in the five isolates studied: clonal type II (TgOvBrRS4), type BrIV (TgOvBrRS2 and TgOvBrRS3) and two new non-archetypal genotypes, ToxoDB-RFLP#270 and #271 (TgOvBrRS1 and TgOvBrRS5, respectively). The genotype structure found in the T. gondii isolates from naturally infected sheep in the southern region of Brazil was revealed to have high diversity. This study confirms the presence of rare circulation of the clonal type II genotype in Brazil.
Foi realizado estudo de coorte retrospectiva com o objetivo de avaliar o impacto do plano de cuidados do Programa de Atenção Domiciliar da Unimed-BH, modalidade Gerenciamento de Casos (PrGC/AD), ...sobre o tempo livre de hospitalização entre os pacientes com 60 anos ou mais assistidos pelo programa. Utilizou-se o modelo de Cox para avaliar o efeito do intervalo entre as visitas domiciliares dos profissionais do programa sobre o tempo livre de hospitalização de 2.943 idosos, ajustado por idade, medicamentos em uso, via de alimentação, úlcera de pressão, déficit cognitivo, dependência física, oxigenioterapia, consultas ambulatoriais e hospitalizações no trimestre anterior. Foram fatores de risco para menor tempo livre de hospitalização: o grau de dependência física, alimentação enteral, oxigenioterapia suplementar, úlceras de pressão e hospitalizações no trimestre anterior. Observouse efeito protetor dose-resposta da frequência de visitas médicas e de enfermagem. Os resultados sugerem que visitas domiciliares regulares de médico e enfermeiro aumentam significativamente o tempo livre de hospitalização nos pacientes assistidos pelo PrGC/AD.
Early diagnosis of leptospirosis may aid in a favorable prognosis in infected animals, but there are few reports of clinical and hematochemical changes in the ovine species, nor whether the breed ...exerts any influence on the response to infection. Thus, the objective of the present study was to evaluate the clinical, biochemical and hematological alterations in Santa Inês and crossbred ewes challenged with Leptospira interrogans serogroup Pomona serovar Kennewicki. Twenty-four sheep were used in this experiment, 12 crossbred (group A) and 12 Santa Inês (group B). In each group, sheep were conjunctivally and intraperitoneally challenged. During 60 days post-infection the ewes were evaluated for the presentation of clinical signs and the blood was collected for hemogram and serum biochemistry. Concentration of urea and creatinine; serum aspartate aminotransferase activity (AST); gamma-glutamyltransferase (GGT); total protein and albumin; total bilirubin, direct and indirect were analyzed. The urine of these sheep was collected for urinalysis. Only two Santa Inês sheep showed blood in the urine. Clinical signs implicated in Leptospira sp. infection were not identified. Some sheep had anemia, especially crossbred. However, anemia may be attributed to the more effective cellular response that has been identified in crossbred animals. Only one animal presented leukocytosis with neutrophilia, while 11 presented atypical leukopenia, especially those of the Santa Inês breed. There was a decrease in total protein and albumin, as well as the increase in gammaglutamyltranspeptidase (GGT), especially in Santa Inês sheep. The level of aspartate aminotransferase (AST) remained within the normal range for the species. A significant increase (p < 0.05) in conjugated bilirubin levels in challenged animals was detected. Only one sheep intraperitoneally challenged presented a high level of urea in the blood, but the creatinine level remained within the normal range. The intraperitoneal route was responsible for more significant changes (p < 0.05) in the hemogram and biochemistry when compared to the conjunctival route. The results indicate that crossbred sheep have a more efficient cellular response than Santa Inês sheep, which may confer a greater resistance to infection. Clinical signs are not good parameters to follow the development of leptospirosis in crossbred and Santa Inês breed. Hematological and biochemical analyzes were useful in the detection of anemia and possible liver changes caused by leptospirosis. The intraperitoneal route was able to cause more conclusive alterations of the analyzed parameters, however, it is possible that the alterations caused by the conjunctival route reproduce in a more faithful way what happens in a natural situation of infection.
Agriculture; Environmental science; Microbiology; Leptospirosis; Intraperitoneal route; Conjunctival route; Santa Inês; Breeds
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