40 research outputs found

    Numerical simulation of lead-free vacancy ordered Cs 2 PtI 6 based perovskite solar cell using SCAPS-1D

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    In recent years, vacancy-ordered halide double perovskites have emerged as promising non-toxic and stable alternatives for their lead-based counterparts in optoelectronic applications. In particular, vacancy ordered Cs2PtI6 has emerged as a star material because of its high absorption coefficient, band gap of 1.37 eV, and long minority carrier lifetime. Despite substantial experimental research on this new class of material, theoretical simulations of their device properties remain scarce. In this work, a novel n-i-p device architecture (FTO/SnO2/Cs2PtI6/MoO3/C) is theoretically investigated using a solar cell capacitance simulator (SCAPS-1D). Theoretical investigations are carried out in order to optimize the device performance structure by varying the perovskite and selective charge transport layer thickness, absorber and interface defect density, operating temperature, back contact, series and shunt resistance, respectively. The optimized device showed an impressive power conversion efficiency (PCE) of 23.52% at 300 K, which is higher than the previously reported values. Subsequent analysis of the device's spectral response indicated that it possessed 98.9% quantum efficiency (QE) and was visibly active. These findings will provide theoretical guidelines for enhancing the performance of Cs2PtI6-based photovoltaic solar cells (PSCs) and pave the way for the widespread implementation of environmentally benign and stable perovskites

    Active anti-acetylcholinesterase component of secondary metabolites produced by the endophytic fungi of Huperzia serrata

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    Background: An endophytic fungus lives within a healthy plant during certain stages of, or throughout, its life cycle. Endophytic fungi do not always cause plant disease, and they include fungi that yield different effects, including mutual benefit, and neutral and pathogenic effects. Endophytic fungi promote plant growth, improve the host plant's resistance to biotic and abiotic stresses, and can produce the same or similar biologically active substances as the host. Thus, endophytic fungal products have important implications in drug development. Result: Among the numerous endophytic fungi, we identified two strains, L10Q37 and LQ2F02, that have anti-acetylcholinesterase activity, but the active compound was not huperzine A. The aim of this study was to investigate the anti-acetylcholinesterase activity of secondary metabolites isolated from the endophytic fungi of Huperzia serrata . Microbial cultivation and fermentation were used to obtain secondary metabolites. Active components were then extracted from the secondary metabolites, and their activities were tracked. Two compounds that were isolated from endophytic fungi of H. serrata were identified and had acetylcholine inhibitory activities. In conclusion, endophytic fungal strains were found in H. serrata that had the same anti-acetylcholinesterase activity. Conclusion: We isolated 4 compounds from the endophytic fungus L10Q37, among them S1 and S3 are new compounds. 6 compounds were isolated from LQ2F02, all 6 compounds are new compounds. After tested anti acetylcholinesterase activity, S5 has the best activity. Other compounds' anti acetylcholinesterase activity was not better compared with huperzine A

    Performance for MIMO-RSN with Different Power Allocation Methods

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    Investigation in MIMO-RSN (Multi-input Multi-output radar sensor networks) is becoming more attractive in current literature. In a MIMO system, power allocation in accordance with the channel gain can significantly improve the system throughput performance. This paper investigates three power allocation methods in MIMO-RSN: water-filling, equal power and channel inversion. Their performances are analyzed in terms of target detection probability, false alarm rate, and amount of information for flat fading channels. Baker code is applied in the transmitting signal with different power control schemes to improve the target detection performance. The simulation results show that the water-filling in MIMO-RSN achieves the best detection performance while the channel inversion gets the worst

    Biophysical properties as determinants for soil organic carbon and total nitrogen in grassland salinization.

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    Grassland salinization causes considerable changes to soil and vegetation, which can lead to changes in soil organic carbon (C) and total nitrogen (N). These changes have complex causal relationships. A significant correlation between soil organic C and total N and any soil or vegetation property does not necessarily imply a significant direct effect of the property on soil organic C and total N. In this study, a field survey was conducted to investigate the changes in soil organic C and total N in grassland along a salinity gradient in Hexi corridor, China, and the direct and indirect effects of soil and vegetation properties on both stocks were quantified using a path analysis approach. Significant decrease in soil organic C and total N contents were observed with increasing salinity. Both had significant positive correlations with the Normalized Difference Vegetation Index (NDVI), soil water, and fine particles (silt+clay) content (p<0.01) and significant negative correlations with soil EC, and sand content (p<0.01). NDVI, fine particles content and soil water content had positive direct effects on soil organic C and total N stocks. Soil EC affected soil organic C and total N stocks mainly through its indirect negative effect on NDVI, soil texture, and water content. NDVI, soil texture, and moisture also indirectly affected soil organic C and total N stocks via changes in each other. These indirect effects augmented each other, although in some cases indirect effects worked in opposing directions

    The Prevalence and Characteristics of Mitral Regurgitation in Heart Failure: A Chart Review Study

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    Background: Mitral regurgitation (MR) is one of the common complications of heart failure (HF). The prevalence and characteristics of MR are rarely investigated, especially in the Chinese population. Objectives: The purpose of this study was to determine the prevalence and characteristics of non-organic MR in HF patients and subgroups defined by ejection fraction. Methods: A single-center, hospital-based, and retrospective chart review study included patients with heart failure admitted to the cardiovascular department from January 2017 to April 2020. Demographic characteristics, laboratory results, and echocardiogram results before discharge were analyzed in different groups defined by left ventricular ejection fraction (EF) using logistic regression and adjusted for confounders. Results: Finally, 2418 validated HF patients (age 67.2 ± 13.5 years; 68.03% men) were included. The prevalence of MR was 32.7% in HF, 16.7% in HF with preserve EF patients, 28.4% in HF with mid-range EF patients and 49.7% in HF with reduced EF (HFrEF) patients. In the HF with preserved EF group, multivariable logistic regression showed that 4 factors associated with MR including EF (odds ratio (OR) 0.954 (0.928–0.981), p = 0.001), left ventricular posterior wall thickness in diastolic phase (LVPWd) (OR 0.274 (0.081–0.932), p = 0.038), left atrium (LA) dimension (OR 2.049 (1.631–2.576), p < 0.001) and age (OR 1.024 (1.007–1.041), p = 0.007). In the HF with midrange EF group, multivariable logistic regression showed that 3 factors associated with MR including LA dimension (OR 2.009 (1.427–2.829), p < 0.001), triglycerides (TG) (OR 0.552 (0.359–0.849), p = 0.007) and digoxin (OR 2.836 (1.624–4.951), p < 0.001). In the HFrEF group, multivariable logistic regression showed that 7 factors associated with MR including EF (OR 0.969 (0.949–0.990), p = 0.004), (OR 0.161 (0.067–0.387), p < 0.001), LA dimension (OR 2.289 (1.821–2.878), p < 0.001), age (OR 1.016 (1.004–1.027)), p = 0.009), TG (OR 0.746 (0.595–0.936), p = 0.011), diuretics (OR 0.559 (0.334–0.934), p = 0.026) and ICD (OR 1.898 (1.074–3.354), p = 0.027). Conclusions: HF patients had a high burden of MR, particularly in the HFrEF group. Worsen cardiac structure (LA dimension and LVPWd) and function (EF), age, and medical treatment strategy played essential roles in MR

    Dr.seq2: A quality control and analysis pipeline for parallel single cell transcriptome and epigenome data

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    <div><p>An increasing number of single cell transcriptome and epigenome technologies, including single cell ATAC-seq (scATAC-seq), have been recently developed as powerful tools to analyze the features of many individual cells simultaneously. However, the methods and software were designed for one certain data type and only for single cell transcriptome data. A systematic approach for epigenome data and multiple types of transcriptome data is needed to control data quality and to perform cell-to-cell heterogeneity analysis on these ultra-high-dimensional transcriptome and epigenome datasets. Here we developed Dr.seq2, a Quality Control (QC) and analysis pipeline for multiple types of single cell transcriptome and epigenome data, including scATAC-seq and Drop-ChIP data. Application of this pipeline provides four groups of QC measurements and different analyses, including cell heterogeneity analysis. Dr.seq2 produced reliable results on published single cell transcriptome and epigenome datasets. Overall, Dr.seq2 is a systematic and comprehensive QC and analysis pipeline designed for parallel single cell transcriptome and epigenome data. Dr.seq2 is freely available at: <a href="http://www.tongji.edu.cn/~zhanglab/drseq2/" target="_blank">http://www.tongji.edu.cn/~zhanglab/drseq2/</a> and <a href="https://github.com/ChengchenZhao/DrSeq2" target="_blank">https://github.com/ChengchenZhao/DrSeq2</a>.</p></div

    DISCO: Memory Efficient and Accurate Flow Statistics for Network Measurement

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    A basic task in network passive measurement is collecting flow statistics information for network state characterization. With the continuous increase of Internet link speed and the number of flows, flow statistics has become a great challenge due to the demanding requirements on both memory size and memory bandwidth in measurement devices. In this paper, we propose a DIScount COunting (DISCO) method, which is designed for both flow size and flow volume counting. For each incoming packet of length l, DISCO increases the corresponding counter assigned to the flow with an increment that is less than l. With an elaborate design on the counter update rule and the inverse estimation, DISCO saves memory consumption while providing an accurate unbiased estimator. The method is evaluated thoroughly under theoretical analysis and simulations with synthetic and real traces. The results demonstrate that DISCO is more accurate than related work given the same counter size. DISCO is also implemented on network processor Intel IXP2850 for performance test. Using only one MicroEngine (ME) in IXP2850, the throughput can reach up to 11.1Gbps under a traditional traffic pattern, and it increases almost linearly with the number of MEs employed
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