196 research outputs found

    Geochemical characteristics of dissolved heavy metals in Zhujiang River, Southwest China: spatial-temporal distribution, source, export flux estimation, and a water quality assessment

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    To investigate the sources and spatial-temporal distribution of dissolved heavy metals in river water, and to evaluate the water quality, a total of 162 water samples were collected from 81 key sampling points in high and low flow seasons separately in the Zhujiang River, Southwest China. Ten dissolved heavy metals (V, Cr, Mn, Co, Ni, Cu, Mo, Cd, Ba, and Pb) in the Zhujiang River water exhibit little variation at temporal scale, but vary with a significant spatial heterogeneity. Furthermore, different metals present different variation trends along the main channel of the Zhujiang River. Our results suggest that Ba (14.72 μg L−1 in low flow season and 12.50 μg L−1 in high flow season) and Cr (6.85 μg L−1 in low flow season and 7.52 μg L−1 in high flow season) are consistently the most abundant metals in the two sampling periods. According to the water quality index (WQI values ranged from 1.3 to 43.9) and health risk assessment, metals investigated in Zhujiang River are below the hazard level (all hazard index (HI) < 1). Application of statistical approaches, including correlation matrix and principal component analysis (PCA), identify three principal components that account for 61.74% of the total variance, the results conclude that the anthropogenic heavy metals (V, Cr, Ni, and Cu) are greatly impacted by the dilution effect, and the heavy metals in Zhujiang River are mainly presented a natural sources signature from the perspective of entire basin. Moreover, our results reveal that the estimated export budget of several heavy metals including V (735.6 t year−1), Cr (1,561.1 t year−1), Ni (498.2 t year−1), and Mo (118.9 t year−1) to the ocean are higher than the world average

    Anthropomorphic Dual-Arm Coordinated Control for a Single-Port Surgical Robot Based on Dual-Step Optimization

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    Effective teleoperation of the small-scale and highly-integrated robots for single-port surgery (SPS) imposes unique control and human-robot interaction challenges. Traditional isometric teleoperation schemes mainly focus on end-to-end trajectory mapping, which is problematic when applied to SPS robotic control, especially for dual-arm coordinated operation. Inspired by the human arm configuration in boxing maneuvers, an optimized anthropomorphic coordinated control strategy based on a dual-step optimization approach is proposed. Theoretical derivation and solvability of the problem are addressed, and the effectiveness of the method is further demonstrated in detailed simulation and in-vitro experiments. The proposed control strategy has been shown to perform dexterous SPS bimanual manipulation more effectively, involving less instrument-interference and is free from singularities, thereby improving the safety and efficiency of SPS operations

    O2ATH: An OpenMP Offloading Toolkit for the Sunway Heterogeneous Manycore Platform

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    The next generation Sunway supercomputer employs the SW26010pro processor, which features a specialized on-chip heterogeneous architecture. Applications with significant hotspots can benefit from the great computation capacity improvement of Sunway many-core architectures by carefully making intensive manual many-core parallelization efforts. However, some legacy projects with large codebases, such as CESM, ROMS and WRF, contain numerous lines of code and do not have significant hotspots. The cost of manually porting such applications to the Sunway architecture is almost unaffordable. To overcome such a challenge, we have developed a toolkit named O2ATH. O2ATH forwards GNU OpenMP runtime library calls to Sunway's Athread library, which greatly simplifies the parallelization work on the Sunway architecture.O2ATH enables users to write both MPE and CPE code in a single file, and parallelization can be achieved by utilizing OpenMP directives and attributes. In practice, O2ATH has helped us to port two large projects, CESM and ROMS, to the CPEs of the next generation Sunway supercomputers via the OpenMP offload method. In the experiments, kernel speedups range from 3 to 15 times, resulting in 3 to 6 times whole application speedups.Furthermore, O2ATH requires significantly fewer code modifications compared to manually crafting CPE functions.This indicates that O2ATH can greatly enhance development efficiency when porting or optimizing large software projects on Sunway supercomputers.Comment: 15 pages, 6 figures, 5 tables

    Variant R94C in TNNT2‐encoded troponin T predisposes to pediatric restrictive dardiomyopathy and sudden death through impaired thin filament relaxation resulting in myocardial diastolic dysfunction

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    Background Pediatric-onset restrictive cardiomyopathy (RCM) is associated with high mortality, but underlying mechanisms of disease are under investigated. RCM-associated diastolic dysfunction secondary to variants i

    Preparation, biological characterization and preliminary human imaging studies of 68Ga-DOTA-IBA

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    PurposeIn this study, DOTA-IBA was radiolabeled with 68Ga and we determined the optimum labelling conditions and assessed the biological properties of 68Ga-DOTA-IBA. We investigated the biodistribution of 68Ga-DOTA-IBA in normal animals and undertook PET/CT imaging in humans. Finally, we explored the feasibility 68Ga-DOTA-IBA as a bone imaging agent and demonstrated its potential for the therapeutic release of 177Lu/225Ac-DOTA-IBA.MethodsThe controlled variables method was used to assess the impact of variables on the radiochemical purity of 68Ga-DOTA-IBA. The biological properties of 68Ga-DOTA-IBA were investigated.68Ga-DOTA-IBA micro-PET/CT imaging was performed on animals. Volunteers were recruited for 68Ga-DOTA-IBA imaging and data were compared to 99mTc-MDP imaging studies to calculate the target to non-target ratio (T/NT) of the lesions.ResultsThe prepared 68Ga-DOTA-IBA had a radiochemical purity of &gt;97% and demonstrated good biological properties with a good safety profile in normal mice. PET/CT imaging of the animals showed rapid blood clearance with high contrast between the bone and stroma. Human imaging showed that 68Ga-DOTA-IBA could detect more lesions compared to 99mTc-MDP and had a higher targeted to untargeted ratio.Conclusions68Ga-DOTA-IBA is an osteophilic radiopharmaceutical that can be synthesized using a simple labelling method. 68Ga-DOTA-IBA has high radiochemical purity and is stable in vitro stability. It is rapidly cleared from the blood, has low toxicity and has strong targeting to the bone with long retention times. We also found that it is rapidly cleared in non-target tissues and has high contrast on whole-body bone imaging. 68Ga-DOTA-IBA PET/CT has potential as a novel bone imaging bone modality in patients with metastatic disease

    Phosphate release contributes to the rate-limiting step for unwinding by an RNA helicase

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    RNA helicases function in numerous aspects of RNA biology. These enzymes are RNA-stimulated ATPases that translocate on RNA and unwind or remodel structured RNA in an ATP-dependent fashion. How ATP and the ATPase cycle fuel the work performed by helicases is not completely clear. The hepatitis C virus RNA helicase, NS3, is an important model system for this class of enzymes. NS3 binding to a single-/double-strand RNA or DNA junction leads to ATP-independent melting of the duplex and formation of a complex capable of ATP-dependent unwinding by using a spring-loaded mechanism. We have established an RNA substrate for NS3 that can be unwound in a single sub-step. Our studies are consistent with a model in which a single ATP binding and/or hydrolysis event sets the unwinding spring and phosphate dissociation contributes to release of the spring, thereby driving the power stroke used for unwinding

    Exploring the shared molecular mechanism of microvascular and macrovascular complications in diabetes: Seeking the hub of circulatory system injury

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    BackgroundMicrovascular complications, such as diabetic retinopathy (DR) and diabetic nephropathy (DN), and macrovascular complications, referring to atherosclerosis (AS), are the main complications of diabetes. Blindness or fatal microvascular diseases are considered to be identified earlier than fatal macrovascular complications. Exploring the intrinsic relationship between microvascular and macrovascular complications and the hub of pathogenesis is of vital importance for prolonging the life span of patients with diabetes and improving the quality of life.Materials and methodsThe expression profiles of GSE28829, GSE30529, GSE146615 and GSE134998 were downloaded from the Gene Expression Omnibus database, which contained 29 atherosclerotic plaque samples, including 16 AS samples and 13 normal controls; 22 renal glomeruli and tubules samples from diabetes nephropathy including 12 DN samples and 10 normal controls; 73 lymphoblastoid cell line samples, including 52 DR samples and 21 normal controls. The microarray datasets were consolidated and DEGs were acquired and further analyzed by bioinformatics techniques including GSEA analysis, GO-KEGG functional clustering by R (version 4.0.5), PPI analysis by Cytoscape (version 3.8.2) and String database, miRNA analysis by Diana database, and hub genes analysis by Metascape database. The drug sensitivity of characteristic DEGs was analyzed.ResultA total of 3709, 4185 and 8086 DEGs were recognized in AS, DN, DR, respectively, with 1820, 1666, 888 upregulated and 1889, 2519, 7198 downregulated. GO and KEGG pathway analyses of DEGs and GSEA analysis of common differential genes demonstrated that these significant sites focused primarily on inflammation-oxidative stress and immune regulation pathways. PPI networks show the connection and regulation on top-250 significant sites of AS, DN, DR. MiRNA analysis explored the non-coding RNA upstream regulation network and significant pathway in AS, DN, DR. The joint analysis of multiple diseases shows the common influenced pathways of AS, DN, DR and explored the interaction between top-1000 DEGs at the same time.ConclusionIn the microvascular and macrovascular complications of diabetes, immune-mediated inflammatory response, chronic inflammation caused by endothelial cell activation and oxidative stress are the three links linking atherosclerosis, diabetes retinopathy and diabetes nephropathy together. Our study has clarified the intrinsic relationship and common tissue damage mechanism of microcirculation and circulatory system complications in diabetes, and explored the mechanism center of these two vascular complications. It has far-reaching clinical and social value for reducing the incidence of fatal events and early controlling the progress of disabling and fatal circulatory complications in diabetes

    Genome-wide identification and expression profiling of auxin response factor (ARF) gene family in maize

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    <p>Abstract</p> <p>Background</p> <p>Auxin signaling is vital for plant growth and development, and plays important role in apical dominance, tropic response, lateral root formation, vascular differentiation, embryo patterning and shoot elongation. Auxin Response Factors (ARFs) are the transcription factors that regulate the expression of auxin responsive genes. The <it>ARF </it>genes are represented by a large multigene family in plants. The first draft of full maize genome assembly has recently been released, however, to our knowledge, the <it>ARF </it>gene family from maize (<it>ZmARF </it>genes) has not been characterized in detail.</p> <p>Results</p> <p>In this study, 31 maize (<it>Zea mays </it>L.) genes that encode ARF proteins were identified in maize genome. It was shown that maize <it>ARF </it>genes fall into related sister pairs and chromosomal mapping revealed that duplication of <it>ZmARFs </it>was associated with the chromosomal block duplications. As expected, duplication of some <it>ZmARFs </it>showed a conserved intron/exon structure, whereas some others were more divergent, suggesting the possibility of functional diversification for these genes. Out of these 31 <it>ZmARF </it>genes, 14 possess auxin-responsive element in their promoter region, among which 7 appear to show small or negligible response to exogenous auxin. The 18 <it>ZmARF </it>genes were predicted to be the potential targets of small RNAs. Transgenic analysis revealed that increased miR167 level could cause degradation of transcripts of six potential targets (<it>ZmARF3</it>, <it>9</it>, <it>16</it>, <it>18</it>, <it>22 </it>and <it>30</it>). The expressions of maize <it>ARF </it>genes are responsive to exogenous auxin treatment. Dynamic expression patterns of <it>ZmARF </it>genes were observed in different stages of embryo development.</p> <p>Conclusions</p> <p>Maize <it>ARF </it>gene family is expanded (31 genes) as compared to <it>Arabidopsis </it>(23 genes) and rice (25 genes). The expression of these genes in maize is regulated by auxin and small RNAs. Dynamic expression patterns of <it>ZmARF </it>genes in embryo at different stages were detected which suggest that maize <it>ARF </it>genes may be involved in seed development and germination.</p
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