The influence of the solvent on the morphology and performance of polymer solar cells is investigated in devices based on blends of the polyfluorene copolymer, poly(2,7‐(9,9‐dioctyl‐fluorene)‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)), and [6,6]‐phenyl‐C61‐butyric acid methyl ester. The blends are spin‐coated from chloroform or from chloroform mixed with small amounts of xylene, toluene, or chlorobenzene. The devices are characterized under monochromatic light and solar illumination AM1.5 (AM: air mass). An enhancement of the photocurrent density is observed in diodes made from chloroform mixed with chlorobenzene, and reduced photocurrent density is observed in diodes made from chloroform mixed with xylene or toluene, compared to diodes made from neat chloroform. The open‐circuit voltages are almost the same in all diodes. The surfaces of the active layers are imaged using atomic force microscopy. Height images indicate that a finer and more uniform distribution of domains corresponds to the diodes with enhanced photocurrent that are made from chloroform mixed with chlorobenzene, while a structure with larger domains is associated with the lower photocurrents in the diodes made from chloroform mixed with xylene or toluene. The influence of the morphology on the excited‐state dynamics and charge generation is investigated using time‐resolved spectroscopy. Fast formation of bound charge pairs followed by their conversion into free charge carriers is resolved, and excitation‐intensity‐dependent non‐geminate recombination of free charges is observed. A significant enhancement in free‐charge‐carrier generation is observed on introducing chlorobenzene into chloroform. Imaging photocurrent generation from the solar cells with a light‐pulse technique shows an inhomogeneous photocurrent distribution, which is related to the undulations in the thickness of the active layer. Thicker parts of the diodes yield higher photocurrent values.

No abstract

Blends of the low-bandgap polymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-5,5- (4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole] (APFO-3) and the fullerene derivative [6,6]-phenyl–C61–butyric acid methyl ester (PCBM) were spin-coated from chloroform solution into thin films, which were examined with dynamic secondary ion mass spectrometry. For blends with high PCBM content, the depth profiles show composition waves that were caused by surface-directed phase separation during spin-coating. The formation of such multilayer structures by spontaneous self-stratification is likely to have implications for optimization strategies for the performance of organic solar cells.

ObjectivesTo estimate the risk of clinically diagnosed knee osteoarthritis (OA) after different types of knee injuries in young adults.MethodsIn a longitudinal cohort study based on population-based healthcare data from Skåne, Sweden, we included all persons aged 25–34 years in 1998–2007 (n=149 288) with and without diagnoses of knee injuries according to International Classification of Diseases (ICD)-10. We estimated the HR of future diagnosed knee OA in injured and uninjured persons using Cox regression, adjusted for potential confounders. We also explored the impact of type of injury (contusion, fracture, dislocation, meniscal tear, cartilage tear/other injury, collateral ligament tear, cruciate ligament tear and injury to multiple structures) on diagnosed knee OA risk.ResultsWe identified 5247 persons (mean (SD) age 29.4 (2.9) years, 67% men) with a knee injury and 142 825 persons (mean (SD) age 30.2 (3.0) years, 45% men) without. We found an adjusted HR of 5.7 (95% CI 5.0 to 6.6) for diagnosed knee OA in injured compared with uninjured persons during the first 11 years of follow-up and 3.4 (95% CI 2.9 to 4.0) during the following 8 years. The corresponding risk difference (RD) after 19 years of follow-up was 8.1% (95% CI 6.7% to 9.4%). Cruciate ligament injury, meniscal tear and fracture of the tibia plateau/patella were associated with greatest increase in risk (RD of 19.6% (95% CI 13.2% to 25.9%), 10.5% (95% CI 6.4% to 14.7%) and 6.6% (95% CI 1.1% to 12.2%), respectively).ConclusionIn young adults, knee injury increases the risk of future diagnosed knee OA about sixfold with highest risks found after cruciate ligament injury, meniscal tear and intra-articular fracture.

No abstract

The disease-associated prion protein (PrP) forms aggregates which vary in structural conformation yet share an identical primary sequence. These variations in PrP conformation are believed to manifest in prion strains exhibiting distinctly different periods of disease incubation as well as regionally specific aggregate deposition within the brain. The anionic luminescent conjugated polythiophene (LCP), polythiophene acetic acid (PTAA) has previously been used to distinguish PrP deposits associated with distinct mouse adapted strains via distinct fluorescence emission profiles from the dye. Here, we employed PTAA and 3 structurally related chemically defined luminescent conjugated oligothiophenes (LCOs) to stain brain tissue sections from mice inoculated with 2 distinct prion strains. Our results showed that in addition to emission spectra, excitation, and fluorescence lifetime imaging microscopy (FLIM) can fruitfully be assessed for optical distinction of PrP deposits associated with distinct prion strains. Our findings support the theory that alterations in LCP/LCO fluorescence are due to distinct conformational restriction of the thiophene backbone upon interaction with PrP aggregates associated with distinct prion strains. We foresee that LCP and LCO staining in combination with multimodal fluorescence microscopy might aid in detecting structural differences among discrete protein aggregates and in linking protein conformational features with disease phenotypes for a variety of neurodegenerative proteinopathies.

Background The occupational risk of COVID-19 may be different in the first versus second epidemic wave. Aim To study whether employees in occupations that typically entail close contact with others were at higher risk of SARS-CoV-2 infection and COVID-19-related hospitalisation during the first and second epidemic wave before and after 18 July 2020, in Norway. Methods We included individuals in occupations working with patients, children, students, or customers using Standard Classification of Occupations (ISCO-08) codes. We compared residents (3,559,694 on 1 January 2020) in such occupations aged 20–70 years (mean: 44.1; standard deviation: 14.3 years; 51% men) to age-matched individuals in other professions using logistic regression adjusted for age, sex, birth country and marital status. Results Nurses, physicians, dentists and physiotherapists had 2–3.5 times the odds of COVID-19 during the first wave when compared with others of working age. In the second wave, bartenders, waiters, food counter attendants, transport conductors, travel stewards, childcare workers, preschool and primary school teachers had ca 1.25–2 times the odds of infection. Bus, tram and taxi drivers had an increased odds of infection in both waves (odds ratio: 1.2–2.1). Occupation was of limited relevance for the odds of severe infection, here studied as hospitalisation with the disease. Conclusion Our findings from the entire Norwegian population may be of relevance to national and regional authorities in handling the epidemic. Also, we provide a knowledge foundation for more targeted future studies of lockdowns and disease control measures.

Aim: To study whether employees in occupations that typically imply close contact with other people are at higher risk of SARS-CoV-2 infection (COVID-19) and related hospitalization, for the 1st and 2nd wave of infection in Norway. Methods: In 3 553 407 residents of Norway on January 1st 2020 aged 20-70 (with mean [SD] age 44.1 [14.3] years and 51% men), we studied whether persons in occupations in touch with pupils/students/patients/customers (using Standard Classification of Occupations [ISCO-08 codes]) had a higher risk of 1) COVID-19 and 2) hospitalization with COVID-19, compared to everyone aged 20-70 years using logistic regression adjusted for age, sex and birth country. Results: Nurses, physicians, dentists, physiotherapists, bus/tram and taxi drivers had 1.5-3.5 times the odds of COVID-19 during the 1st wave of infection when compared to everyone in their working age. In the 2nd wave of the epidemic, bartenders, waiters, food service counter attendants, taxi drivers and travel stewards had 1.5-4 times the odds of COVID-19 when compared to everyone in their working age. Teachers had no or only a moderately increased odds of COVID-19. Occupation may be of limited relevance for the odds of severe COVID-19, here studied as hospitalization with the disease. Conclusion: Studying the entire Norwegian population using international standardized codes of occupations, our findings may be of relevance to national and regional authorities in handling the epidemic. Also, our findings provide a knowledge foundation for the more targeted future studies of lockdown and disease control measures.