62 research outputs found

    Proton radiation effects on carrier transport in diamond radiation detectors

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    Diamond, a highly radiation-resistant material, is considered a nearly ideal material for radiation detection, particularly in high-energy physics. In this study, radiation damage from high-energy proton beams was induced in diamond crystals to determine exposure lifetime in detectors made from this material; the effects were investigated using non-destructive x-ray techniques and through the FLUKA simulation package. Two diamond detectors were irradiated by an 800 MeV proton beam at different fluence rates, and the real-time current response was recorded to observe degradation in the signal over time. It was determined that the proton fluence rate had a significant effect on the device degradation. The detector performance from the irradiated detectors was characterized using x-ray beam-induced current measurements, and the mechanism of proton radiation damage to diamond sensors, especially the radiation effects on carrier transport, was studied. The vacancies generated from proton irradiation were considered the major source of detector degradation by trapping holes and inducing an internal electric field. Simulation results from the FLUKA package revealed an uneven distribution of the radiation-induced vacancies along the beam path, and the corresponding detector signals calculated from the simulation results displayed a good match to the experimental results

    Transcriptomic and functional analyses reveal the molecular mechanisms underlying Fe-mediated tobacco resistance to potato virus Y infection

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    Potato virus Y (PVY) mainly infects Solanaceous crops, resulting in considerable losses in the yield and quality. Iron (Fe) is involved in various biological processes in plants, but its roles in resistance to PVY infection has not been reported. In this study, foliar application of Fe could effectively inhibit early infection of PVY, and a full-length transcriptome and Illumina RNA sequencing was performed to investigate its modes of action in PVY-infected Nicotiana tabacum. The results showed that 18,074 alternative splicing variants, 3,654 fusion transcripts, 3,086 long non-coding RNAs and 14,403 differentially expressed genes (DEGs) were identified. Specifically, Fe application down-regulated the expression levels of the DEGs related to phospholipid hydrolysis, phospholipid signal, cell wall biosynthesis, transcription factors (TFs) and photosystem I composition, while those involved with photosynthetic electron transport chain (PETC) were up-regulated at 1 day post inoculation (dpi). At 3 dpi, these DEGs related to photosystem II composition, PETC, molecular chaperones, protein degradation and some TFs were up-regulated, while those associated with light-harvesting, phospholipid hydrolysis, cell wall biosynthesis were down-regulated. At 9 dpi, Fe application had little effects on resistance to PVY infection and transcript profiles. Functional analysis of these potentially critical DEGs was thereafter performed using virus-induced gene silencing approaches and the results showed that NbCat-6A positively regulates PVY infection, while the reduced expressions of NbWRKY26, NbnsLTP, NbFAD3 and NbHSP90 significantly promote PVY infection in N. benthamiana. Our results elucidated the regulatory network of Fe-mediated resistance to PVY infection in plants, and the functional candidate genes also provide important theoretical bases to further improve host resistance against PVY infection

    Cell transcriptomic atlas of the non-human primate Macaca fascicularis.

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    Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell-cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.We thank W. Liu and L. Xu from the Huazhen Laboratory Animal Breeding Centre for helping in the collection of monkey tissues, D. Zhu and H. Li from the Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory) for technical help, G. Guo and H. Sun from Zhejiang University for providing HCL and MCA gene expression data matrices, G. Dong and C. Liu from BGI Research, and X. Zhang, P. Li and C. Qi from the Guangzhou Institutes of Biomedicine and Health for experimental advice or providing reagents. This work was supported by the Shenzhen Basic Research Project for Excellent Young Scholars (RCYX20200714114644191), Shenzhen Key Laboratory of Single-Cell Omics (ZDSYS20190902093613831), Shenzhen Bay Laboratory (SZBL2019062801012) and Guangdong Provincial Key Laboratory of Genome Read and Write (2017B030301011). In addition, L.L. was supported by the National Natural Science Foundation of China (31900466), Y. Hou was supported by the Natural Science Foundation of Guangdong Province (2018A030313379) and M.A.E. was supported by a Changbai Mountain Scholar award (419020201252), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16030502), a Chinese Academy of Sciences–Japan Society for the Promotion of Science joint research project (GJHZ2093), the National Natural Science Foundation of China (92068106, U20A2015) and the Guangdong Basic and Applied Basic Research Foundation (2021B1515120075). M.L. was supported by the National Key Research and Development Program of China (2021YFC2600200).S

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

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    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Research on the Green Effect of Environmental Policies—From the Perspective of Policy Mix

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    Environmental protection policy serves as an effective means for the government to curb environmental pollution and promote high-quality economic development. The government must weigh the effects of different policy mixes. From the perspective of policy combination, this paper discusses the green effect of environmental protection policy theoretically and empirically. First and foremost, this paper sorts out the reforming time of environmental protection taxes and the situation of the low-carbon pilot city, and puts forward two hypotheses. Furthermore, by referring to the environmental protection tax, the policy for the low-carbon pilot city, and the urban air quality indicator from 2014 to 2020, this paper explores the green effect of the environmental protection policy and further validates the consolidation effect of the policy mix on the green effect. The study reveals a significant decrease in the air pollution level in regions with higher standards for levying an environmental protection tax. The conclusion remains robust via parallel trend testing and substitution of the subject variables. Furthermore, an analysis of the policy mix of an environmental protection tax indicates that the policy mix of an environmental protection tax and low-carbon city produces a significant green effect, which not only curbs air pollution but also reduces greenhouse gas emissions. An in-depth analysis shows that an environmental protection tax has the best green effect in the first and second areas of a low-carbon pilot market. The synergies of low-carbon pilot effects are higher in areas with low and middle tax rates

    Analysis of the Impact of Interest Rate Liberalization on Financial Services Management in Chinese Commercial Banks

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    With the advancement of China's interest rate marketization reform, commercial banks' net interest margin has narrowed. This paper selects 16 representative listed banks as the research object and conducts an empirical analysis from the two dimensions: profit level and profit structure. The study finds that the marketization of interest rates promoted the narrowing of net interest margins caused by the narrowing of net interest margins, and the profitability of commercial banks was suppressed. The narrowing of net interest spreads forced commercial banks to actively expand their intermediate business activities and adjust business structure correspondingly. The narrowing of net interest spreads has different impacts on the profitability of commercial banks of different sizes

    Built-up edge formation mechanisms in orthogonal cutting of wood-plastic composite

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    This project aims to improve the machinability of wood-plastic composites by understanding chip and built-up edge formation, so as to help manufacturers optimize cutting performance and product quality. Chip formation and built-up edge were studied during orthogonal cutting of wood polyethylene composite with cemented carbide cutters under different conditions. During the orthogonal cutting process, segmental, ribbon, and element chips were generated. The cutting depth was found to have a great impact on the types of chips that formed. Additionally, a built-up edge was found during wood-plastic composite machining, with debris only attaching to the tool's rake face due to thermo-mechanical coupling. Such built-up edges hinder cutting stability and surface quality. Furthermore, variations in the accumulation of debris on the built-up edge corresponded to changes in cutting force and temperature. In fact, both cutting force and temperature proved to be inversely related to the rake angle and positively correlated to the cutting speed and depth. Therefore, to achieve better cutting stability and surface quality for wood-plastic composites, a larger rake angle and a reduced cutting depth are recommended because they reduce the accumulation of debris and the formation of built-up edge.Validerad;2022;Nivå 2;2022-11-29 (joosat);Funder: National Natural Science Foundation of China (31971594); Natural Science Foundation of the Jiangsu Higher Education Institutions of China (21KJB220009); Self-Made Experimental and Teaching Instruments of Nanjing Forestry University (nlzzyq202101); Technology Innovation Alliance of Wood/Bamboo Industry (TIAWBI2021-08); International Cooperation Joint Laboratory for Production, Education, Research and Application of Ecological Health Care on Home Furnishing</p

    Research on the Bearing Sliding Loss Based on Time-Varying Contact Angle between Ball and Raceway

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    Based on the mechanical model, the friction loss between the ball and the raceway along the major axis of the contact ellipse is analyzed. The result shows that this part of the loss accounts for about 13.67% of the overall loss, which is mainly determined by the ball sliding length and cannot be ignored. The effects of the radial force, torque, rotational speed and groove curvature ratio on the sliding are all studied. Compared with other factors, radial force has the greatest influence on the sliding loss. As bearing speed gradually grows, the sliding on the inner raceway gradually increases while it gradually decreases on the outer raceway. Compared to the outer raceway curvature ratio, the sliding length is less sensitive to changes in the curvature ratio of the inner raceway. The paper provides theoretical guidance for the design and application of low-friction bearings

    Generating micro/nanostructures on magnesium alloy surface using ultraprecision diamond surface texturing process

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    The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications. However, micro/nanostructure generation on their surfaces remains a challenge due to the flammability and ignition. Motivated by this, this study proposed a machining process, named the ultraprecision diamond surface texturing process, to machine the micro/nanostructures on magnesium alloy surfaces. Experimental results showed the various microstructures and sawtooth-shaped nanostructures were successfully generated on the AZ31B magnesium alloy surfaces, demonstrating the effectiveness of this proposed machining process. Furthermore, sawtooth-shaped nanostructures had the function of inducing the optical effect and generating different colors on workpiece surfaces. The colorful letter and colorful flower image were clearly viewed on magnesium alloy surfaces. The corresponding cutting force, chip morphology, and tool wear were systematically investigated to understand the machining mechanism of micro/nanostructures on magnesium alloy surfaces. The proposed machining process can further improve the performances of the magnesium alloy and extend its functions to other fields, such as optics
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