Organometallic halide perovskite films with good surface morphology and large grain size are desirable for obtaining high‐performance photovoltaic devices. However, defects and related trap sites are ...generated inevitably at grain boundaries and on surfaces of solution‐processed polycrystalline perovskite films. Seeking facial and efficient methods to passivate the perovskite film for minimizing defect density is necessary for further improving the photovoltaic performance. Here, a convenient strategy is developed to improve perovskite crystallization by incorporating a 2D polymeric material of graphitic carbon nitride (g‐C3N4) into the perovskite layer. The addition of g‐C3N4 results in improved crystalline quality of perovskite film with large grain size by retarding the crystallization rate, and reduced intrinsic defect density by passivating charge recombination centers around the grain boundaries. In addition, g‐C3N4 doping increases the film conductivity of perovskite layer, which is beneficial for charge transport in perovskite light‐absorption layer. Consequently, a champion device with a maximum power conversion efficiency of 19.49% is approached owing to a remarkable improvement in fill factor from 0.65 to 0.74. This finding demonstrates a simple method to passivate the perovskite film by controlling the crystallization and reducing the defect density.
Graphitic carbon nitride (g‐C3N4) is incorporated into the perovskite precursor solution to modify the perovskite film by controlling the perovskite crystallization, reducing the intrinsic defect density, and improving the film conductivity. As a result, a champion device with a maximum power conversion efficiency of 19.49% is approached.
Cytokine storm is a general term applied to maladaptive cytokine release in response to infection and other stimuli. The pathogenesis is complex but includes loss of regulatory control of ...proinflammatory cytokine production, both at local and systemic levels. The disease progresses rapidly, and the mortality is high. Some evidence shows that, during the coronavirus disease 2019 (COVID-19) epidemic, severe deterioration in some patients has been closely associated with dysregulated and excessive cytokine release. This article reviews what we know of the mechanism and treatment strategies of the COVID-19 virus-induced inflammatory storm in an attempt to provide some background to inform future guidance for clinical treatment.
Recently, the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) Omicron variant (B.1.1.529) was first identified in Botswana in November 2021. It was first reported to the World Health ...Organization (WHO) on November 24. On November 26, 2021, according to the advice of scientists who are part of the WHO's Technical Advisory Group on SARS‐CoV‐2 Virus Evolution (TAG‐VE), the WHO defined the strain as a variant of concern (VOC) and named it Omicron. Compared to the other four VOCs (Alpha, Beta, Gamma, and Delta), the Omicron variant was the most highly mutated strain, with 50 mutations accumulated throughout the genome. The Omicron variant contains at least 32 mutations in the spike protein, which was twice as many as the Delta variant. Studies have shown that carrying many mutations can increase infectivity and immune escape of the Omicron variant compared with the early wild‐type strain and the other four VOCs. The Omicron variant is becoming the dominant strain in many countries worldwide and brings new challenges to preventing and controlling coronavirus disease 2019 (COVID‐19). The current review article aims to analyze and summarize information data about the biological characteristics of amino acid mutations, the epidemic characteristics, immune escape, and vaccine reactivity of the Omicron variant, hoping to provide a scientific reference for monitoring, prevention, and vaccine development strategies for the Omicron variant.
Highlights
The Omicron variant was the most highly mutated variant of concerns (VOCs).
The Omicron variant spread faster than the original virus strain and other VOCs.
The Omicron variant produces a higher risk of reinfection than the other variants.
Bearings are widely used in various electrical and mechanical equipment. As their core components, failures often have serious consequences. At present, most parameter adjustment methods are still ...manual adjustments of parameters. This adjustment method is easily affected by prior knowledge, easily falls into the local optimal solution, cannot obtain the global optimal solution, and requires a lot of resources. Therefore, this paper proposes a new method for bearing fault diagnosis based on wavelet packet transform and convolutional neural network optimized by a simulated annealing algorithm. Firstly, the original bearing vibration signal is extracted by wavelet packet transform to obtain the spectrogram, and then the obtained spectrogram is sent to the convolutional neural network for parameter adjustment, and finally the simulated annealing algorithm is used to adjust the parameters. To verify the effectiveness of the method, the bearing database of Case Western Reserve University is used for testing, and the traditional intelligent bearing fault diagnosis methods are compared. The results show that the new method for bearing fault diagnosis proposed in this paper has a better and more reliable diagnosis effect than the existing machine learning and deep learning methods.
There is currently enough systematic literature presents about socioeconomic inequalities across different disciplines. However, this study relates socioeconomic inequality (SEI) to rural students ...educational management information systems (EMIS) in different schools in China. The dynamic force of information technology could not be constrained in the modern techno-based world. Similarly, the study was qualitative and ethnographic. Data were collected through an interview guide and analyzed with thematic scientific analysis. Ten male and ten female students were interviewed based on data saturation point. The purposive sampling technique was used for the rural school and students’ selection. This study summarizes the findings and brings together in-depth emic and etic findings based on new Marxist conflict theory, exploitation, and domination power lens. The study found that SEI creates disparities among EMIS. Household income inequality has influenced on educational achievements of rural areas’ students. Gender-based SEI was not present among students. Family wealth and SES-based exploitation are present regarding EMIS among male and female students. Household wealth is significant for the EMIS. The study put forward a recommendation to the policymakers that exploitation could be overcome among students if the government provides equal opportunities for access to the EMIS.
Coronavirus disease 2019 (COVID‐19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has led to an unprecedented setback for global economy and health. Vaccination is ...one of the most effective interventions to substantially reduce severe disease and death due to SARS‐CoV‐2 infection. Vaccination programmes are being rolled out globally, but most of these vaccines have been approved without extensive studies on their side‐effects and efficacy. Recently, new‐onset autoimmune phenomena after COVID‐19 vaccination have been reported increasingly (e.g. immune thrombotic thrombocytopenia, autoimmune liver diseases, Guillain–Barré syndrome, IgA nephropathy, rheumatoid arthritis and systemic lupus erythematosus). Molecular mimicry, the production of particular autoantibodies and the role of certain vaccine adjuvants seem to be substantial contributors to autoimmune phenomena. However, whether the association between COVID‐19 vaccine and autoimmune manifestations is coincidental or causal remains to be elucidated. Here, we summarize the emerging evidence about autoimmune manifestations occurring in response to certain COVID‐19 vaccines. Although information pertaining to the risk of autoimmune disease as a consequence of vaccination is controversial, we merely propose our current understanding of autoimmune manifestations associated with COVID‐19 vaccine. In fact, we do not aim to disavow the overwhelming benefits of mass COVID‐19 vaccination in preventing COVID‐19 morbidity and mortality. These reports could help guide clinical assessment and management of autoimmune manifestations after COVID‐19 vaccination.
As vaccination programmes are being rolled out globally, new‐onset autoimmune phenomena are emerging after COVID‐19 vaccination (e.g. immune thrombotic thrombocytopenia, autoimmune liver diseases, Guillain–Barré syndrome, IgA nephropathy, rheumatoid arthritis and systemic lupus erythematosus).
Exploiting organic/inorganic hybrid perovskite solar cells (PSCs) with reduced Pb content is very important for developing environment‐friendly photovoltaics. Utilizing of Pb–Sn alloying perovskite ...is considered as an efficient route to reduce the risk of ecosystem pollution. However, the trade‐off between device performance and Sn substitution ratio due to the instability of Sn2+ is a current dilemma. Here, for the first time, the highly efficient Pb–Sn–Cu ternary PSCs are reported by partial replacing of PbI2 with SnI2 and CuBr2. Sn2+ substitution results in a redshift of the absorption onset, whereas worsens the film quality. Interestingly, Cu2+ introduction can passivate the trap sites at the crystal boundaries of Pb–Sn perovskites effectively. Consequently, a power conversion efficiency as high as 21.08% in inverted planar Pb–Sn–Cu ternary PSCs is approached. The finding opens a new route toward the fabrication of high efficiency Pb–Sn alloying perovskite solar cells by Cu2+ passivation.
Pb–Sn–Cu ternary perovskite solar cells are fabricated by partially replacing PbI2 with SnI2 and CuBr2. Sn2+ substitution results in a redshift of the absorption onset, but worsens the film quality. Cu2+ substitution paves a route to passivating the trap sites at the crystal boundaries. As a result, a maximum PCE of 21.08% is achieved with improved cell stabiilty.
During the COVID-19 pandemic, SARS-CoV-2 variants have emerged and spread worldwide. The Delta (B.1.617.2) variant was first reported in India in October 2020 and was classified as a "variant of ...concern (VOC)" by the WHO on 11 May, 2021. Compared to the wild-type strain, several studies have shown that the Delta variant is more transmissible and has higher viral loads in infected samples. COVID-19 patients infected with the Delta variant have a higher risk of hospitalization, intensive care unit (ICU) admission, and mortality. The Delta variant is becoming the dominant strain in many countries around the world. This review summarizes and analyses the biological characteristics of key amino acid mutations, the epidemic characteristics, and the immune escape of the Delta variant. We hope to provide scientific reference for the monitoring and prevention measures of the SARS-CoV-2 Delta variant and the development strategy of a second-generation vaccine.
Coronavirus disease 2019 (COVID-19) is a respiratory infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Droplets and contacts serve as the main route of ...transmission of SARS-CoV-2. The characteristic of the disease is rather heterogeneous, ranging from no symptoms to critical illness. The factors associated with the outcome of COVID-19 have not been completely characterized to date. Inspired by previous studies on the relevance of infectious diseases, viral and host factors related to clinical outcomes have been identified. The severity of COVID-19 is mainly related to host factors, especially cellular immune responses in patients. Patients with mild COVID-19 and improved patients with severe COVID-19 exhibit a normal immune response to effectively eliminate the virus. The immune response in patients with fatal severe COVID-19 includes three stages: normal or hypofunction, hyperactivation, and anergy. Eventually, the patients were unable to resist viral infection and died. Based on our understanding of the kinetics of immune responses during COVID-19, we suggest that type I interferon (IFN) could be administered to patients with severe COVID-19 in the hypofunctional stage, intravenous immunoglobulin (IVIG) and glucocorticoid therapy could be administered in the immune hyperactivation stage. In addition, low molecular weight heparin (LMWH) anticoagulation therapy and anti-infective therapy with antibiotics are recommended in the hyperactivation stage.
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