48 research outputs found
Sex-specific effects of psychoactive pollution on behavioral individuality and plasticity in fish
Lay Summary Prozac is present in freshwater systems across the globe as the pharmaceutical contaminant fluoxetine. The effect of fluoxetine on aquatic species' behavioral variability is not yet clear. We show that male guppies become more similar to each other after exposure to fluoxetine, and females become less flexible in their behavior. These sex-specific differences in response to fluoxetine can have a meaningful impact on their ability to survive in a changing world.The global rise of pharmaceutical contaminants in the aquatic environment poses a serious threat to ecological and evolutionary processes. Studies have traditionally focused on the collateral (average) effects of psychoactive pollutants on ecologically relevant behaviors of wildlife, often neglecting effects among and within individuals, and whether they differ between males and females. We tested whether psychoactive pollutants have sex-specific effects on behavioral individuality and plasticity in guppies (Poecilia reticulata), a freshwater species that inhabits contaminated waterways in the wild. Fish were exposed to fluoxetine (Prozac) for 2 years across multiple generations before their activity and stress-related behavior were repeatedly assayed. Using a Bayesian statistical approach that partitions the effects among and within individuals, we found that males-but not females-in fluoxetine-exposed populations differed less from each other in their behavior (lower behavioral individuality) than unexposed males. In sharp contrast, effects on behavioral plasticity were observed in females-but not in males-whereby exposure to even low levels of fluoxetine resulted in a substantial decrease (activity) and increase (freezing behavior) in the behavioral plasticity of females. Our evidence reveals that psychoactive pollution has sex-specific effects on the individual behavior of fish, suggesting that males and females might not be equally vulnerable to global pollutants
Idiopathic calcinosis cutis of the scrotum: a case report and review of the literature
Abstract Background Abnormal deposition of calcium in the skin or subcutaneous tissue is termed calcinosis cutis. Idiopathic calcinosis cutis of the scrotum is an uncommon entity. The pathogenesis of idiopathic calcinosis cutis of the scrotum is debatable. The condition presents as several brown to yellowish nodules on the scrotum, gradually progressive, and mostly asymptomatic. Here we report a case of idiopathic calcinosis cutis of the scrotum with a brief review of the literature and a discussion on pathogenesis. Case presentation A healthy looking, 50-year-old Nepali man presented with multiple growths on his scrotum for 15 years, which were mostly asymptomatic with an occasional complaint of itching. On physical examination, multiple pink to brown nodules ranging in size from 0.5 × 0.5 × 0.5 cm to 3 × 3 × 1 cm, which were painless and firm in consistency, were noted. On laboratory examinations the following were found to be within normal limits: serum calcium, phosphorus, parathyroid hormone, and vitamin D hormone levels; uric acid; alkaline phosphatase; and lipid profile. Based on clinical features and laboratory reports, a diagnosis of idiopathic calcinosis cutis of the scrotum was made. The nodules were excised under local anesthesia in several sittings, which gave a good cosmetic result with no evidence of recurrence in 1-year follow-up period. A histopathological examination revealed dermis with areas of fibrosis and calcification along with numerous multinucleated giant cells and an absence of any cystic structure. Conclusions Idiopathic calcinosis cutis of the scrotum is a benign condition, which remains mostly asymptomatic. It presents as progressive multiple nodules of varying numbers and sizes. A histopathological evaluation reveals areas of calcification. The cause is either dystrophic calcification of cysts or idiopathic. Excision is the treatment of choice
Enhanced electron transport enables over 12% efficiency by interface engineering of non-fullerene organic solar cells
Organic solar cells have attracted much attention in the recent years due to their many intrinsic advantages, such as, light weight, flexibility, low-cost, solution processing, and facile device fabrication. In this study, effective interface engineering was employed to improve all the photovoltaic parameters of an organic solar cell simultaneously by incorporating ZnO nanoparticle (ZnO-NP) interlayer in between the indium tin oxide cathode and sol-gel processed ZnO electron transport layer. The significance of incorporating a ZnO-NP/ZnO bilayer as the electron transport layer in the bulk heterojunction organic solar cells was demonstrated via systematic study, employing a high efficiency photoactive layer system (PBDB-T:ITIC). The bilayer electron transport layer demonstrated reduced work function compared to the sol-gel ZnO, which enabled effective electron transfer from the active layer to the electron transport layer. In addition, improved bilayer surface morphology, via reduction of ZnO-NP layer roughness, and better crystallinity compared to sol-gel ZnO facilitated charge separation and transmission between electron transport layer and active layer. Consequently, the devices with bilayer interlayer exhibited an enhancement of > 13% in power conversion efficiency compared to the control devices with sol-gel only ZnO as electron transport layer. The mechanisms behind the improvement in device performance were analysed using the ultraviolet and X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. The champion bilayer device exhibited 12.24% efficiency which is much higher than the efficiency of 10.69% for the control device
High-efficiency semitransparent organic solar cells with non-fullerene acceptor for window application
Organic solar cells possess multiple desirable traits, such as low cost, flexibility, and semitransparency, which opens up potential avenues unavailable to other solar technologies, a prime example of this being window applications. For this specific application, a delicate balance between the transmission of light through the device and power conversion efficiency (PCE), dependent on the amount of light absorbed, must be optimized. Here, we report a high-efficiency semitransparent device based on a novel fullerene-free material system. Using an active layer based on the material system PBDB-T:ITIC, optimized devices exhibited PCEs exceeding 7% while also achieving an average visible transmittance (AVT) of 25%. The concurrent demonstration of high efficiency with an AVT of 25% represents a notable step forward for semitransparent organic solar cells. Additionally, the influence of the active layer thickness on the color rendering properties of these cells was studied. Optimization of the active layer thickness can lead to high-efficiency cells, with high visible transmission as well as the ability to display an image accurately
Effect of annealing dependent blend morphology and dielectric properties on the performance and stability of non-fullerene organic solar cells
This work demonstrates the influence of annealing temperature on the phase morphology of the polymer-non-fullerene blend and its relationship with the dielectric constants of the blend layer. It is also the first study to report the annealing induced changes in dielectric environment of the active layer blend employing non-fullerene acceptor. Polymer solar cells (PSCs) annealed at 80 °C were found to possess optimal blend morphology favourable for efficient charge separation owing to reduced coulomb capture radius and relatively high dielectric constant, resulting in high power conversion efficiency (PCE) of ~11.4%. The high performing devices fabricated at optimized temperature also exhibited superior charge transport characteristics including high recombination resistance (Rrec) which is 31% higher than the non-annealed devices. The effect of intermolecular aggregation induced by the annealing temperature and its relationship with the disorder states in the blend layer, influencing the electron transport properties is also investigated in detail. Furthermore, a month long degradation study investigating the operational stability of the as-developed non-fullerene based PSCs was also performed and analysed
Sensitization of PTB7: PC 71 BM organic solar cells using Si-PCPDTBT
No Abstract Availabl
Effect of PCBM film thickness on the performance of inverted perovskite solar cells
No Abstract Availabl
Optimization of conjugated polymer blend concentration for high performance organic solar cells
Recently, conjugated polymer poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3′′′-di(2-octyldodecyl)-2,2′;5′,2″;5″,2′′′-quaterthiophen-5,5′′′-diy)] (PffBT4T-2OD), gained immense attention among the researchers for the photovoltaic device—owing to high temperature processability, high crystallinity and superior charge transport characteristics. In addition, PffBT4T-2OD displays a unique aggregation property which plays a crucial role in determining the quality of the photoactive blend film and concomitantly influencing the organic photovoltaic (OPV) device performance substantially. Here we demonstrate the detailed investigation into the mechanisms governing the aggregation properties of PffBT4T-2OD:PC71BM blend and its role in determining the interfacial properties—material and electronic; together influencing the device performance as a whole. Spectroscopic analysis (XRD and FTIR) indicate that increasing the blend composition influences the aggregation properties in the film, as a function of increased side chain and polymer backbone interactions. Contact angle measurements showed that this, in turn, greatly influences the wettability of the photoactive layer with the adjacent electron transporting layer (ETL) surface. Impedance spectroscopy measurements revealed that the modified surface properties significantly result in the variation of charge transport characteristics across the ETL/polymer interface. The OPV devices employing the optimized blend concentration 33 mg/ml with favourable aggregation properties exhibits high power conversion efficiency of about 9.6% which is 45% higher than the reference device. A detailed relationship between the aggregation characteristics and the related variation in the interfacial properties is correlated with the device performance
Photo-degradation of high efficiency fullerene-free polymer solar cells
Polymer solar cells are a promising technology for the commercialization of low cost, large scale organic solar cells. With the evolution of high efficiency (>13%) non-fullerene polymer solar cells, the stability of the cells has become a crucial parameter to be considered. Among the several degradation mechanisms of polymer solar cells, burn-in photo-degradation is relatively less studied. Herein, we present the first systematic study of photo-degradation of novel PBDB-T:ITIC fullerene-free polymer solar cells. The thermally treated and as-prepared PBDB-T:ITIC solar cells were exposed to continuous 1 sun illumination for 5 hours. The aged devices exhibited rapid losses in the short-circuit current density and fill factor. The severe short-circuit current and fill factor burn in losses were attributed to trap mediated charge recombination, as evidenced by an increase in Urbach energy for aged devices