Search

• The double- or multi-buffer structures for CdTe solar cells were proposed on the foundation of energy band analysis. • The feasibility of the graded design for back contacting via extending double structure to multi structures was demonstrated. • The best back buffer should be a composite of different materials for realizing collective contribution in CdTe solar cells. Back buffer materials play a significant role in improving both open-circuit voltage and fill factor, and developing new materials and structures can be essential for further improvement. In this paper, we have compared the different cases with only one buffer and concluded that single buffer layer always has some innate defects because of the actual constraints. And on the foundation of detailed energy band analysis, we propose that a double- or multi- back buffer structure has the potential to fully mitigate the disadvantage of a single layer and combine the strengths of different materials. The simulation based on this theory demonstrates that the combination of different layers behaves as what we expected and outputs much better performance. It is shown that two layers with reasonable alignment and suitable carrier density are nearly enough for most cases while for extreme cases, more layers are required. Our further simulation provides real designs based on different kinds of back buffer materials, and this work might be instructional for designing new back buffer structures. [ABSTRACT FROM AUTHOR]

Antibiotics are widely consumed in the intensive mariculture industry. A better understanding of the effect of antibiotics on intergenerational antibiotic resistance in organisms is urgent since intergenerational transmission is crucial for the spread of antibiotic resistance genes (ARGs) in the environment. Herein, marine medaka (Oryzias melastigma) chronically exposed to low doses of sulfamethazine (SMZ) hormetically affected the progeny, characterized by increased richness and diversity of fecal microbiota and intestinal barrier-related gene up-regulation. Progeny immunity was modulated and caused by genetic factors due to the absence of significant SMZ accumulation in F1 embryos. In addition, some of the top genera in the progeny were positively correlated with immune diseases, while the expression of some immune-related genes, such as TNFα , IL1R2 , and TLR3 changed significantly. This further indicated that the host selection caused by changes in progeny immunity was probably the primary determinant of progeny intestinal microbial colonization. Metagenomic analysis revealed that Proteobacteria represented the primary carriers of ARGs, while parental SMZ exposure facilitated the distribution and enrichment of multiple ARGs involved in the antibiotic inactivation in the progeny by promoting the diversity of Gammaproteobacteria and Bacteroidetes, further illustrating that antibiotic selection pressure persisted even if the offspring were not exposed. Therefore, SMZ induced hormesis in the progeny at the expense of increasing antibiotic resistance. Collectively, these findings provide a comprehensive overview of the intergenerational effect of antibiotics and serve as a reminder that the ARG transmission induced by the intergenerational impact of antibiotics on organisms should not be ignored. [Display omitted] • Parental sulfamethazine exposure induced hormesis in the progeny of marine medaka. • Immune changes of progeny (host selection) determined gut microbial colonization. • Hormesis occurred in the progeny at the cost of increasing antibiotic resistance. • Gammaproteobacteria and Bacteroidetes were the dominant hosts of specific ARGs. [ABSTRACT FROM AUTHOR]

Microplastics and antibiotics widely coexist in the aquatic environment, especially in mariculture regions. However, antibiotics adsorbed on microplastics and their role in the colonization of microorganisms on microplastics are poorly understood. Therefore, in-situ aging experiments were conducted to investigate the impact of antibiotics and microplastics co-occurrence on microorganisms and assess their potential risks to human health. Results showed that antibiotics were adsorbed selectively on microplastics, with 29 investigated antibiotics (n = 40) detected in surrounding water but only 6 investigated antibiotics were adsorbed on microplastics. The concentration of antibiotics accumulated on microplastics was controlled by microplastic types and environmental conditions. For example, aged polypropylene (PP) had more developed pore structures resulting in higher adsorption of antibiotics than other microplastic types. High-throughput sequencing showed higher diversity and distinct composition of microorganisms attached to the microplastics than the surrounding water. Opportunistic pathogenic bacteria such as Mycobacterium possessed positive relationships with tetracycline and doxycycline on aged microplastics, which showed adsorbed antibiotics on aged microplastics could benefit some specific pathogens colonized on the microplastics and spread into unaffected ecosystems, marine organisms even humans. The health risk quotient (HQ) implied the potential human health risk of consuming commercial seafood polluted by antibiotics and microplastic loaded with antibiotics. This study revealed the interaction of antibiotics and microorganisms with aged microplastics in aquaculture systems, providing a novel insight into their synergistic effects on ecological and human health. [Display omitted] • Aging under environmentally realistic conditions reveals the adsorption of microplastics. • Microplastic types and environmental conditions influence the antibiotics adsorption of microplastics. • Antibiotics adsorbed on aged microplastics benefit the colonization of Mycobacterium and Pseudomonas on microplastics. • The coexisting of antibiotics and microplastics aggravates the potential human health risk of ingesting commercial seafood. [ABSTRACT FROM AUTHOR]

The plasticizer di (2-ethylhexyl) phthalate (DEHP) is becoming increasingly abundant throughout the global environment as plastic pollution becomes highly severe, especially in the ocean. The adverse effects of DEHP have garnered increasing concern as they are recognized as endocrine disruptors. However, information on the effects of DEHP in marine organisms remains limited. In this study, acute toxic effects on marine medaka (Oryzias melastigma) following DEHP exposure were investigated. Transcriptome analysis was performed on the livers of medaka exposed to DEHP for 6 and 24 h. Results showed that 1595 genes were affected in all the analyzed specimens, and several genes expressed variably according to sex. Some pathways associated with immunity, metabolism, and endocrine system were significantly enriched, with the complement system appearing to be the most affected immune pathway. Pathway enrichment indicated that, under acute DEHP exposure, the immune response of females tended to be more sensitive than that of males. In addition, ferroptosis occurred in response to DEHP exposure, which resulted in an enrichment of the ferroptosis pathway along with iron overload, an increase in malondialdehyde (MDA) and lipid peroxidation (LPO) content, and a decrease in glutathione (GSH) levels. These results indicate that a form of cell death characterized by iron-dependence occurred following DEHP exposure, but the underlying mechanism requires further analysis. This study implies that DEHP can alter some molecular regulation patterns within a short period and induce cell death through ferroptosis. Image 1 • DEHP induced the enrichment of immune, metabolism pathways in marine medaka. • Complement system appeared to be the most affected immune pathway in marine medaka. • Female immune response seemed to be more sensitive than males under DEHP exposure. • Ferroptosis occurred in marine medaka following DEHP exposure. [ABSTRACT FROM AUTHOR]

Benzo[a]pyrene (BaP), a widely existed polycyclic aromatic hydrocarbon pollutant in aquatic environment, has toxic effects on marine animals and their generations, but the intergenerational immunotoxic mechanism underlying has not been clearly understood. In the study, the offspring of marine medaka (oryzias melastigma) which were exposed to 0.5 μg L−1 BaP suffered from circadian rhythm oscillation disorders and severe DNA damage. Many clock-associated genes like per1 were significantly modulated in offspring, both per1 and p53 were significantly inhibited that altered the progression of cell cycle and inhibited DNA repair, which possibly resulted in the increased mortality of offspring. The hypermethylation of the per1 promotor and abnormal levels of N6-methyladenosine (m6A) suggested that the underlying mechanism was probably related to the epigenetic modification. Moreover, the offspring from paternal BaP exposure had more severe DNA damage and a higher degree of hypermethylation than those from maternal exposure. F1 larvae from BaP-exposed parents were more sensitive to BaP exposure, showing that the expression of immune and metabolism-related genes were significantly up-regulated. Taken together, the parental toxicity induced by BaP could be passed to F1 generation and the mechanism underlying was probably associated with a characteristic circadian rhythm disorder. Image 1 • Parental BaP exposure induced circadian rhythm disorder in offspring. • Parental BaP exposure caused immune disorder in offspring through per1 and p53. • The possible mechanism was related to per1 promotor methylation and RNA methylation. • The offspring from BaP exposed males suffered more serious effects. • F1 larvae from BaP exposed parents were more sensitive to BaP. The parental toxicity induced by BaP could be passed to F1 generation and the underlying mechanism was probably associated with circadian rhythm disorder. [ABSTRACT FROM AUTHOR]

Transparent MoO x thin films with varied composition were successfully prepared by sputtering and the effects of oxygen contents on the composition stoichiometry, defect states, work functions, electrical and optical properties of MoO x films were systematically studied. These thin films were then utilized in cadmium telluride solar cells to act as back contact buffers. As compared with the CdTe solar cells with Au back contact, deteriorated performance was witnessed in those with MoO x buffers. The deterioration was demonstrated to be caused by the oxidation of CdTe surface, the large valence band offset and the insufficient work function. Finally, by optimizing the back contacts to form a CuCl/MoO x /ITO composite back contact, the efficiency was improved to 11.8%. This work demonstrates feasible approaches to prepare MoO x thin films with varied oxygen concentrations which could be easily applied to many other thin film solar cells and provide important indications in the preparation and optimization of the performance for bifacial devices. • The effects of oxygen contents on the properties of sputtered MoO x films were studied. • The performance deterioration mechanism of CdTe solar cell with MoO x back contact was clarified. • By forming a CuCl/MoOx/ITO composite back contact, the efficiency was improved to 11.8%. [ABSTRACT FROM AUTHOR]

• The interactions between resveratrol and gut microbiota on hepatic steatosis are investigated. • The fecal microbiota transplantation is used to investigate the interactions. • Resveratrol can reverse high-fat-diet induced dysbiosis. • Resveratrol can ameliorate the hepatic steatosis by regulating gut microbiota. To investigate whether resveratrol could ameliorate the hepatic steatosis in high-fat diet (HFD) fed mice by modulating gut microbiota composition, fecal microbiota transplantation (FMT) was utilized in this study. Our results showed that resveratrol significantly ameliorated hepatic steatosis in HFD mice, increased the gene expression of fasting-induced adipose factor, and decreased the expression of lipogenesis-related genes and proteins (SREBP-1, FAS and ACC). In addition, resveratrol reversed HFD-induced gut microbiota dysbiosis, with an increase in the relative abundance of Bacteroidetes and a decrease in that of Firmicutes and Proteobacteria. Subsequent results showed the gut microbiota compositions of FMT recipient groups were similar to those of corresponding donor groups. And the changes of state of hepatic steatosis and expression of SREBP-1, ACC and FAS were coordinated with the results of gut microbiota. In conclusion, these results provided evidence to support the resveratrol could ameliorate the hepatic steatosis by modulating the gut microbiota. [ABSTRACT FROM AUTHOR]

Ohmic back contact is one of the keys to fabricate high efficient CdTe solar cells, as it can improve fill factor FF and open-circuit voltage V oc. In this work, antimony-containing reduced graphene oxide (RGO) was prepared and used as a back contact for CdTe thin film solar cells, in which antimony is an effective dopant for CdTe and RGO acts as a hole transport layer and diffusion barrier of antimony in the solar cells. Post deposition annealing was performed to activate the back contact layer and passivate the interface defect states. Electrical performance and apparent quantum efficiency characterization were performed to investigate device performance of CdTe solar cells with antimony-containing RGO back contacts. The results indicate that, the introduction of extrinsic doping near the CdTe back surface serves to reduce the back contact depletion width and enhance the built-in potential to enable the tunnelling of majority carrier holes through the barrier, and the RGO is beneficial for the formation of Ohmic back contact on CdTe. [ABSTRACT FROM AUTHOR]

Highlights • Novel TO/ZMO buffer structure for improved CdTe device performance was demonstrated. • TO/ZMO bilayer buffer improves the band-alignment of front contact. • TO/ZMO bilayer buffer reduces recombination and facilitates electron extraction. • The mechanisms of the CdTe device with TO/ZMO bilayer buffer were discussed. Abstract Achieving high open-circuit voltage (V o c) for CdTe thin film solar cells is challenging. We report that a ZnMgO (ZMO) buffer can improve V o c and the performance of CdTe solar cells when deposited on the tin oxide (SnO 2 or TO) coated fluorine-doped tin oxide (FTO) substrates. The TO/ZMO bilayer buffer brings a better energy band matching at the front contact of CdTe thin film solar cells, which can reduce interface carrier recombination and facilitate electron extraction. Our best-performing CdTe solar cell using the TO/ZMO bilayer buffer has achieved a power conversion efficiency of 16.76%, with an open-circuit voltage of 838.75 mV, a short-circuit current density of 27.32 mA cm−2, and a fill factor of 73.14%, much higher than those of devices based on TO buffer. Our results suggest that a careful interface modification of front contact layers provides a simple and effective route to further improving the performance of CdTe solar cells with a higher V o c. [ABSTRACT FROM AUTHOR]

• The Weibull function was used to fit stem radius variations in cold seasons. • Stem shrinkage in Picea meyeri was greater on the forest edge after stem freeze. • The diurnal temperature range regulated the freeze-induced seasonal and diurnal variations in stem size. • Stem freeze or thaw was active when the daily minimum air temperature was around −2.5 °C. Dendrometer-derived stem radius variations (SRV) have been demonstrated as useful tools to test cold acclimation, which could reflect the tree water (ice) balance in winter and thus the frost stress. However, most previous studies focus on stem increment and water relations during growing seasons, stem radius variations in cold seasons and the underlying tree physiological information are not fully exploited, limiting our understanding of the response of mid- and high-latitudinal forests to warming winter. Hourly SRV in spruces (Picea meyeri) across an elevational transect of 700 m were observed over 6 consecutive years (2012–2017) in the present study. Elevation-specific variations in the onset of stem freeze and thaw, and the magnitude of seasonal and diurnal SRV in cold seasons were explored, and ultimately their dominant environmental factors were determined. Before stem freeze, seasonal and diurnal SRV showed linear trends with elevation, which were mainly affected by air and soil water conditions. Whereas, after stem freeze, the seasonal SRV and thus the stem dehydration was greater at the lower and upper limits of the forest belt, and the daily amplitude of freeze-thaw cycles was greater at high elevations. The diurnal air temperature range dominantly controlled the SRV on different time scales after stem freeze. Stem freeze and thaw in P. meyeri was active when the daily minimum air temperature was -2.5 °C in our study region. The onset of stem freeze and thaw advanced and delayed with elevation corresponding to a rate of 5.2 and 7.5 days/ °C when adjusted for the monitored lapse rate of 0.63 °C per 100 m, respectively. Together these findings highlight the value of high-precision variations in stem size to indicate the potential freezing stress, and trees growing at high elevations might suffer greater stress caused by frost dehydration and freeze-thaw under ongoing climate change. [ABSTRACT FROM AUTHOR]

Herein, we developed a novel integrated apparatus to perform phase separation based on magnetic-stirring, salt-induced, liquid–liquid microextraction for determination of five fluoroquinolones in animal-based foods by HPLC analysis. The novel integrated apparatus consisted of three simple HDPE (high density polyethylene) parts that were used to separate the solvent from the aqueous solution prior to retrieving the extractant. The extraction parameters were optimized using the response surface method based on central composite design: 791 μL of acetone solvent, 2.5 g of Na 2 SO 4 , pH 1.7, 3.0 min of stir time, and 5.5 min centrifugation. The limits of detection were 0.07–0.53 μg kg −1 and recoveries were 91.6–105.0% for the five fluoroquinolones from milk, eggs and honey. This method is easily constructed from inexpensive materials, extraction efficiency is high, and the approach is compatible with HPLC analysis. Thus, it has excellent prospects for sample pre-treatment and analysis of fluoroquinolones in animal-based foods. [ABSTRACT FROM AUTHOR]