Reduced voltage losses yield 10% efficient fullerene free organic solar cells with >1 V open circuit voltages.

Optimization of the energy levels at the donor-acceptor interface of organic solar cells has driven their efficiencies to above 10%. However, further improvements towards efficiencies comparable with inorganic solar cells remain challenging because of high recombination losses, which empirically limit the open-circuit voltage (Voc) to typically less than 1 V. Here we show that this empirical limit can be overcome using non-fullerene acceptors blended with the low band gap polymer PffBT4T-2DT leading to efficiencies approaching 10% (9.95%). We achieve Voc up to 1.12 V, which corresponds to a loss of only Eg/q - Voc = 0.5 ± 0.01 V between the optical bandgap Eg of the polymer and Voc. This high Voc is shown to be associated with the achievement of remarkably low non-geminate and non-radiative recombination losses in these devices. Suppression of non-radiative recombination implies high external electroluminescence quantum efficiencies which are orders of magnitude higher than those of equivalent devices employing fullerene acceptors. Using the balance between reduced recombination losses and good photocurrent generation efficiencies achieved experimentally as a baseline for simulations of the efficiency potential of organic solar cells, we estimate that efficiencies of up to 20% are achievable if band gaps and fill factors are further optimized.

Rotavirus G and P types in children with acute diarrhea in Cairo, Egypt, 2011-2012.

BACKGROUND: The WHO estimated the annual rotavirus-related mortality among children below 5 years old in Egypt in 2004 to be 30 deaths per 100 000, or out of an estimated 2616 deaths, 3.9% were because of rotavirus infection. The aim of this article was to study the epidemiology and circulating genotypes of rotaviruses in Cairo from 2011 to 2012. MATERIALS AND METHODS: A total of 197 stool samples were collected from 130 inpatient children at the Cairo University Children Hospital and 67 outpatient children at the Al-Saff Children Clinic. The collected stool samples were then screened for rotavirus using enzyme immunoassay, followed by a screening for G-type and P-type using RT-PCR, and confirmation by sequence analysis. RESULTS: Rotavirus was detected in 39.1% (77/197) of the children, with a higher rate in inpatients (43.9%, 57/130) than in outpatients (29.9%, 20/67). There was an increase of rotavirus infection in the winter season. The majority of rotavirus cases (85.7%) occurred during the first year of life. The predominant genotypes identified during this study were G3P[8] (37.7%) and G1P[8] (19.5%), but uncommon genotypes G1P[6] (3.9%), G9P[6] (1.3%), G8P[14] (1.3%), and G12P[6] (2.6%) were also detected. CONCLUSION AND RECOMMENDATIONS: The change in genotype distribution, compared with previous studies, along with the high burden of rotavirus-associated diarrhea among Egyptian children below 2 years old, emphasizes the importance of continuing strain surveillance and the need of developing and introducing rotavirus vaccine in Egypt.

Frequency of Firmicutes and Bacteroidetes in gut microbiota in obese and normal weight Egyptian children and adults.

INTRODUCTION: Obesity and associated metabolic disorders are a worldwide epidemic. Recent evidence suggests that the microbial community in the human intestine may play an important role in the pathogenesis of obesity. The aim of this study was to assess the differences in the composition of the intestinal microbiota between obese and normal weight Egyptian children and adults. MATERIAL AND METHODS: The study included 79 subjects among whom 51 were obese (23 children and 28 adults), and 28 were subjects of normal weight (17 children and 11 adults). Faecal samples were collected from all subjects. Total DNA was extracted from collected stool samples and submitted to conventional PCR for detection of Firmicutes and Bacteroidetes. All the studied group was subjected to clinical and anthropometric evaluation. Laboratory assessment of fasting glucose, high-sensitivity C-reactive protein (hsCRP) and lipid profile was performed. RESULTS: The proportions of the phyla Firmicutes and Bacteroidetes were statistically significantly increased in the obese group compared to the normal weight group (p < 0.001, p = 0.003 respectively). The study also found a statistically significant positive trend for higher hsCRP in subjects with positive Firmicutes (p = 0.004). However, no associations were found between positive Bacteroidetes and hsCRP. CONCLUSIONS: The results of this study indicate that obesity in Egyptian children and adults is associated with compositional changes in faecal microbiota with increase in the phyla Firmicutes and Bacteroidetes. This could be considered when developing strategies to control obesity and its associated diseases by modifying the gut microbiota.