Search

A computational fluid dynamics (CFD) model for double-sided friction stir spot welding (FSSW) between AZ31 and ZK60 magnesium alloys using adjustable pins is proposed in this paper. Multiple phase flow theories are combined to track the metal interface and phase distribution using FLUENT software. The heat transfer and material flow for the 5 stages of the friction stir welding process, including the pre-heating, plunging, welding, rising and post-heating stages, are presented. For further evaluation, the calculated flow and thermal responses are compared with experimental data, which overall showed good agreement. The material between the upper and lower pins is softened after the pre-heating process and is then driven by the plunging pin to form a keyhole below the upper tool and a bulge region in the bottom of the plates. The welding interface between the pins is bowl-shaped after plunging, and grows uneven during the welding stage due to the extensive plastic material flow. The keyhole is then fully eliminated after the rising of the pins. After welding, the region between the tools is heated to a maximum temperature of 670 K and the welding interface slightly fluctuates and a phase mixing phenomenon occurs, suggesting that AZ31 and ZK60 plates are well joined by using the adjustable pins.

This study re-assess the environmental impacts of the Dexing copper mine (the largest open-pit copper mine in Asia) on the Lean river and its two tributaries (the Dawu river and Jishui river) in the Jiangxi province, China, with particular focus on metal pollution as well as the effectiveness and side-effects of remediation activities. Results show that the Dawu river and its mixing zone with the Lean river were still heavily influenced by acid mine drainage (AMD) and loaded with elevated levels of metals, in particular Mn, Ni, and Al whose concentrations were frequently above the health-based guideline values. Manganese and Ni in the AMD-impacted waters were predicted to occur as free ions or sulfate and carbonate complexes, and thus highly-toxic to living organisms. Although Al in the AMD-impacted waters was predicted to exist largely as colloidal hydroxides with low bioavailability, abundant formation of such nano-sized particles could impair the respiratory and circulatory systems of aquatic macro-invertebrates. The integration and comparison of the results from the current and previous studies show that the concentrations of several metals (Cu, Zn, and Cd) in the Dawu river decreased significantly after 2011–2012, during which several remediation practices were implemented (e.g., AMD neutralization, excavation of contaminated sediments in impounded rivers, and rehabilitation of mine tailings and open-pit slopes). This provides evidence that these remediation practices have effectively limited the dispersion of metals from the mining area. However, AMD neutralization greatly enhanced the release of sulfate, making the mining area an even more important sulfate source.

We present radio observations of the most slowly rotating known radio pulsar PSR J0250+5854. With a 23.5 s period, it is close, or even beyond, the $P$-$\dot{P}$ diagram region thought to be occupied by active pulsars. The simultaneous observations with FAST, the Chilbolton and Effelsberg LOFAR international stations, and NenuFAR represent a five-fold increase in the spectral coverage of this object, with the detections at 1250 MHz (FAST) and 57 MHz (NenuFAR) being the highest- and lowest-frequency published respectively to date. We measure a flux density of $4\pm2$ $\mu$Jy at 1250 MHz and an exceptionally steep spectral index of $-3.5^{+0.2}_{-1.5}$, with a turnover below $\sim$95 MHz. In conjunction with observations of this pulsar with the GBT and the LOFAR Core, we show that the intrinsic profile width increases drastically towards higher frequencies, contrary to the predictions of conventional radius-to-frequency mapping. We examine polarimetric data from FAST and the LOFAR Core and conclude that its polar cap radio emission is produced at an absolute height of several hundreds of kilometres around 1.5 GHz, similar to other rotation-powered pulsars across the population. Its beam is significantly underfilled at lower frequencies, or it narrows because of the disappearance of conal outriders. Finally, the results for PSR J0250+5854 and other slowly spinning rotation-powered pulsars are contrasted with the radio-detected magnetars. We conclude that magnetars have intrinsically wider radio beams than the slow rotation-powered pulsars, and that consequently the latter's lower beaming fraction is what makes objects such as PSR J0250+5854 so scarce., Comment: 14 pages, 6 figures

In the context of the global pandemic of COVID-19, the epidemic intensity, epidemic characteristics and infection risk of influenza have presented new features. COVID-19 and influenza have simultaneously emerged in many regions of the world. COVID-19 and influenza are similar in terms of transmission mode, clinical symptoms and other aspects. There are also similarities in the mechanism of influenza virus and novel coronavirus on cells. At the same time, it is feasible and significant to do a good job in the prevention and control of COVID-19 and influenza. This paper discusses the relevant strategies and measures for the joint prevention and control of influenza and novel coronavirus from the aspects of influenza vaccination to prevent co-infection, simultaneous vaccination of influenza vaccine and novel coronavirus vaccine, etc., and puts forward corresponding thoughts and suggestions, in order to provide scientific support for the formulation of strategies on seasonal influenza vaccine and novel coronavirus vaccination.在新型冠状病毒肺炎（新冠肺炎）全球大流行的环境下，流感的流行强度、流行特征和人群的感染风险均呈现出新的特点，且全球多地区已出现新冠肺炎和流感共同流行的情况。新冠肺炎和流感的传播方式、临床症状等方面相似，流感病毒与新型冠状病毒对细胞的作用机制上也存在相似之处，同时做好新冠肺炎和流感的防控工作具有较强可行性和重大现实意义。本文从流感疫苗接种预防共同感染、流感疫苗和新冠病毒疫苗同时接种等方面，探讨了流感和新冠共同防控的相关策略和措施，提出了相应的思考和建议，以期为季节性流感疫苗和新型冠状病毒疫苗接种策略的制订提供科学支撑。.

To explore the efficacy and value of personalized surgical schemes in the repair of maxillary sinus perforation and maxillary sinus fistula based on the size of the maxillary sinus perforation and maxillary sinus fistula. A total of 28 patients with maxillary sinus perforation and maxillary sinus fistula who were admitted to the Department of Oral and Maxillofacial Surgery, Stomatology Hospital of Kunming Medical University from July 2017 to May 2020 were included to conduct a prospective case clinical study. After the inflammation in the maxillary sinus was controlled, a proper surgical repair method was selected according to the size of the perforation and fistula based on the double-layer closure technique. The diameter of the perforation and fistula was measured with the assistance of cone-beam CT. After that, the platelet rich fibrin (PRF) repair was performed on the perforation and fistula with 3 mm≤diameter7 mm in size in 14 patients. The PRF repair and buccal flap repair were performed on the perforation and fistula with 7 mm ≤diameter15 mm in size in 7 patients. The adjacent buccal pad repair, palatine flap repair, and buccal flap repair were performed on the perforation and fistula with 15 mm≤ diameter25 mm in size in 4 patients. The nasolabial axial flap repair and nasolabial free flap repair were performed on the perforation and fistula with a diameter ≥25 mm in size in 3 patients. The medical follow-up was conducted in all patients in the 1st, 2nd, and 4th week after surgery, with an overall success rate reaching 96.4% (27/28) after the initial intervention. The relapse of disease occurred in one patient (4.6%) with diabetes and a smoking history in the 2nd week after surgery. Identifying a proper surgical repair method according to the size of the oral and maxillary sinus perforation and maxillary sinus fistula based on the double-layer closure technique can improve the one-time cure rate in these patients under the premise that the inflammation in the maxillary sinus can be controlled.根据患者上颌窦穿孔及上颌窦瘘孔大小，选择个性化手术方案，探索在口腔上颌窦穿孔及上颌窦瘘修复中的应用疗效和意义。纳入2017年7月至2020年5月就诊于昆明医科大学附属口腔医院口腔颌面外科的口腔上颌窦穿孔及上颌窦瘘患者28例，进行前瞻性病例临床研究。在保证上颌窦内炎症得以控制的情况下，以双层封闭技术为核心，根据穿孔及瘘孔的大小选择相应的手术修复方法。通过锥形束CT测量穿孔和瘘孔直径大小，对直径≥3 mm且7 mm的14例患者，采用富血小板纤维蛋白（platelet rich fibrin，PRF）填充修复法；对直径≥7 mm且15 mm 的7例患者，采用PRF+颊侧组织瓣修复方法；对直径≥15 mm且25 mm的4例患者，采用邻位颊脂垫组织瓣+腭侧组织瓣+颊侧组织瓣重叠修复法；对直径≥25 mm的3例患者，采用鼻唇沟轴型皮瓣或鼻唇沟任意皮瓣修复法。所有患者在术后第1、2、4周随访检查，初次干预后总成功率为96.4%（27/28）；1例（4.6%）患者术后第2周复发。在保证上颌窦内炎症得以控制的情况下，以双层封闭技术为核心，根据穿孔及瘘孔的大小程度选择相应的手术修复方法，可提高口腔与上颌窦穿孔及上颌窦瘘的一次性治愈率。.

Background The preservation of biological and physiological vitality as well as the formation of dentin are among the main tasks of human dental pulp for a life time. Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) exhibits the capacity of dental pulp regeneration and dentin complex rebuilding. Exploration of the mechanisms regulating differentiation and proliferation of hDPSCs may help to investigate potential clinical applications. BTB and CNC homology 1 (BACH1) is a transcription repressor engaged in the regulation of multiple cellular functions. This study aimed to investigate the effects of BACH1 on the proliferation and odontoblastic differentiation of hDPSCs in vitro. Methods hDPSCs and pulpal tissues were obtained from extracted human premolars or third molars. The distribution of BACH1 was detected by immunohistochemistry. The mRNA and protein expression of BACH1 were examined by qRT-PCR and Western blot analysis. BACH1 expression was regulated by stable lentivirus-mediated transfection. Cell proliferation and cell cycle were assessed by cell counting kit-8 assay, 5-Ethynyl-2'-deoxyuridine assay and flow cytometry. The expression of mineralization markers, alkaline phosphatase (ALP) activity and alizarin red S staining were conducted to assess the odontoblastic differentiation ability. Results BACH1 expression was stronger in the odontoblast layer than in the cell rich zone. The total and nuclear protein level of BACH1 during odontoblastic differentiation was downregulated initially and then upregulated gradually. Knockdown of BACH1 greatly inhibited cell proliferation, arrested cell cycle, upregulated the heme oxygenase-1 (HO-1) expression and attenuated ALP activity, decreased calcium deposits and downregulated the expression of mineralization markers. Treatment of Tin-protoporphyrin IX, an HO-1 inhibitor, failed to rescue the impaired odonto/osteogenic differentiation capacity. Overexpression of BACH1 increased cell proliferation, ALP activity and the expression of mineralization markers. Conclusions Our findings suggest that BACH1 is an important regulator of the proliferation and odontoblastic differentiation of hDPSCs in vitro. Manipulation of BACH1 expression may provide an opportunity to promote the regenerative capacity of hDPSCs.

The proximate analysis of coal, which aims to estimate the moisture, volatile matter, and caloric value, is of great importance for coal processing and evaluation. However, traditional methods for proximate analysis in the laboratory are not only time-consuming and labor-intensive but also expensive. The near-infrared spectroscopy (NIRS) technique provides a rapid and nondestructive method for coal proximate analysis. We exploit two regression methods, random forest (RF) and extreme learning machine (ELM), to model the relationships among spectral data and proximate analysis parameters. In addition, given the poor stability and robustness caused by the random selection of parameters in ELM, we employ the particle swarm optimization algorithm (PSO) to optimize the structure of ELM (PSO–ELM). A total of 384 coal samples from Inner Mongolia are collected for model training and validation. The experimental results show that the proposed PSO–ELM algorithm achieves the best performance in terms of accuracy and efficiency, which indicates that NIRS combined with PSO–ELM has significant potential for accurate and rapid proximate analysis.

Background and objective Immune-mediated diarrhea and colitis (IMDC) is a common adverse event in cancer patients receiving immune checkpoint inhibitors (ICIs). Gastrointestinal (GI) infections can co-occur with IMDC, and its impact on the course and outcome of IMDC remains unclear. Patients and methods We retrospectively reviewed cancer patients who received ICIs and developed IMDC between January 2015 and September 2019. GI multiplex panel is used to assess GI infection. The study group included patients with positive infection except those who are only positive for Clostridioides difficile or cytomegalovirus. The control group is IMDC patients with negative infection using frequency matching. Patients' disease course and outcome were compared between groups. Results A total of 72 patients with IMDC were included: 22 in the study group and 50 as control. Escherichia coli of different pathotypes was observed in 17 patients. Five patients had viral infections, for example, adenovirus, norovirus, and sapovirus. Patients with GI infections more frequently had grade 3 or 4 colitis (43% vs. 18%, P=0.041). Overall, GI infections were not associated with different risks of IMDC recurrence or overall survival. Antibiotics treatment did not affect the requirement for infliximab or vedolizumab but relate to a higher risk of IMDC recurrence (50.0% vs. 0.0%, P=0.015). Conclusions In our study, concomitant GI infections are associated with more severe symptoms in IMDC patients. Antimicrobial treatment did not circumvent the need for immunosuppressive therapy for IMDC or improve the clinical outcome. Concomitant GI infection was not associated with a higher risk of IMDC recurrence or poor overall survival.

BACKGROUND & AIMS Cirrhosis disrupts the hypothalamic-pituitary-gonadal axis causing low testosterone. Testosterone deficiency is associated with sarcopenia and osteopenia, leading to a state of frailty and worse clinical outcomes, morbidity and mortality. We aimed to conduct a systematic review on the relationship between serum testosterone and laboratory, anthropometric and clinical outcomes in observational and interventional studies in cirrhosis. METHODS PubMed and EMBASE were searched from inception through 27 August 2020 and reviewed independently by two investigators; a third reviewer solved disagreement. A qualitative summary of relevant findings was done. Methodological quality was assessed using the Newcastle Ottawa Scale for non-interventional studies and the Cochrane Risk of Bias for interventional studies. RESULTS Out of 3569 articles, 15 met inclusion criteria with six observational studies of 1267 patients and nine interventional studies of 580 patients. In observational studies, low serum testosterone level was associated with sarcopenia, shorter median time to hepatic decompensation, transplant requirement, higher model for end-stage liver disease (MELD) scores, and death in cirrhotic patients. Nine interventional studies (361 treated with testosterone vs 219 placebo, 1-36 months) showed that testosterone supplementation improved serum testosterone, appendicular mass and bone mineral density. However, no trial reported improvement in liver-related scores, complications, readmission rates or death. CONCLUSIONS Low serum testosterone is associated with increased morbidity and mortality in cirrhosis patients. Testosterone supplementation improved intermediate endpoints, but there was no conclusive data on clinical outcomes. Testosterone supplementation may be a promising strategy to improve frailty and decrease significant clinical complications in cirrhosis.

Gross primary productivity (GPP) quantifies the amount of carbon dioxide (CO2) fixed by plants through photosynthesis. Although as a key quantity of terrestrial ecosystems, there is a lack of high-spatial-and-temporal-resolution, real-time and observation-based GPP products. To address this critical gap, here we leverage a state-of-the-art vegetation index, near-infrared reflectance of vegetation (NIRV), along with accurate photosynthetically active radiation (PAR), to produce a SatelLite Only Photosynthesis Estimation (SLOPE) GPP product for the contiguous United States (CONUS). Compared to existing GPP products, the proposed SLOPE product is advanced in its spatial resolution (250 m versus >500 m), temporal resolution (daily versus 8 d), instantaneity (latency of 1 d versus >2 weeks) and quantitative uncertainty (on a per-pixel and daily basis versus no uncertainty information available). These characteristics are achieved because of several technical innovations employed in this study: (1) SLOPE couples machine learning models with MODIS atmosphere and land products to accurately estimate PAR. (2) SLOPE couples highly efficient and pragmatic gap-filling and filtering algorithms with surface reflectance acquired by both Terra and Aqua MODIS satellites to derive a soil-adjusted NIRV (SANIRV) dataset. (3) SLOPE couples a temporal pattern recognition approach with a long-term Cropland Data Layer (CDL) product to predict dynamic C4 crop fraction. Through developing a parsimonious model with only two slope parameters, the proposed SLOPE product explains 85 % of the spatial and temporal variations in GPP acquired from 49 AmeriFlux eddy-covariance sites (324 site years), with a root-mean-square error (RMSE) of 1.63 gC m−2 d−1. The median R2 over C3 and C4 crop sites reaches 0.87 and 0.94, respectively, indicating great potentials for monitoring crops, in particular bioenergy crops, at the field level. With such a satisfactory performance and its distinct characteristics in spatiotemporal resolution and instantaneity, the proposed SLOPE GPP product is promising for biological and environmental research, carbon cycle research, and a broad range of real-time applications at the regional scale. The archived dataset is available at https://doi.org/10.3334/ORNLDAAC/1786 (download page: https://daac.ornl.gov/daacdata/cms/SLOPE_GPP_CONUS/data/, last access: 20 January 2021) (Jiang and Guan, 2020), and the real-time dataset is available upon request.

The Houston Consensus Conference and American College of Gastroenterology (ACG) have recommended Helicobacter pylori screening in United States populations with specific risk factors. However, the performance of these guidelines in clinical practice is not known.We identified consecutive patients undergoing upper endoscopy with gastric biopsies for any indication in a safety-net hospital in Houston, TX during January 2015-December 2016. We tested the association between the presence of H pylori (histopathology, stool antigen, urea breath test, immunoglobulin G serology, or prior treatment) and H pylori risk factors using logistic regression models, reported as odds ratios and 95% confidence intervals (CIs). We evaluated the area under the receiver operating characteristic (AUROC) curve for predictive ability of individual risk factors identified by the Houston Consensus Conference and ACG.Of 942 patients, the prevalence of H pylori infection was 51.5%. The risk factors with the highest predictive performance included first-generation immigrant (AUROC, 0.59) and Hispanic or black race/ethnicity (AUROC, 0.57), whereas the remaining 7 risk factors/statements had low predictive value. A model that combined first-generation immigrant status, black or Hispanic race/ethnicity, dyspepsia, and reflux had higher predictive ability for H pylori infection (AUROC, 0.64; 95% CI, 0.61-0.68) than any individual risk factor.In this contemporary U.S. cohort, the performance of individual risk factors identified by the Houston Consensus Conference and ACG was generally low for predicting H pylori infection except for black or Hispanic race/ethnicity and first-generation immigrant status. A risk prediction model combining several risk factors had improved diagnostic performance and should be validated in future studies.

Hardness is an essential mechanical indication of cemented carbides. The current work presents an approach to predict the hardness of three-phase WC?Co?Cubic cemented carbides, which establishes a relationship among composition, structure and mechanical performance. With the input of initial composition and grain sizes of carbides, structural parameters needed to predict the hardness can be calculated by thermodynamic calculations and diffusion simulations. The calculated hardness of a series of WC?Co?Cubic cemented carbides agrees reasonably with the experimental data. The present model is of reference to predict the hardness for multi-phase composites and design the new type of WC?Co-based cemented carbides.

Summary To facilitate scientific collaboration on polygenic risk scores (PRSs) research, we created an extensive PRS online repository for 35 common cancer traits integrating freely available genome-wide association studies (GWASs) summary statistics from three sources: published GWASs, the NHGRI-EBI GWAS Catalog, and UK Biobank-based GWASs. Our framework condenses these summary statistics into PRSs using various approaches such as linkage disequilibrium pruning/p value thresholding (fixed or data-adaptively optimized thresholds) and penalized, genome-wide effect size weighting. We evaluated the PRSs in two biobanks: the Michigan Genomics Initiative (MGI), a longitudinal biorepository effort at Michigan Medicine, and the population-based UK Biobank (UKB). For each PRS construct, we provide measures on predictive performance and discrimination. Besides PRS evaluation, the Cancer-PRSweb platform features construct downloads and phenome-wide PRS association study results (PRS-PheWAS) for predictive PRSs. We expect this integrated platform to accelerate PRS-related cancer research.

Pain is extremely multifaceted in nature, with physical injury being just one of its causes. The most commonly prescribed therapeutic intervention for acute as well as chronic pain (postoperative or otherwise) is Opioids. Opioid analgesics act via the opioid receptors (G protein coupled), that are widely distributed in the central and peripheral nervous system as well as the gastrointestinal tract, producing pain relief. The opioid analgesics are divided into distinct categories depending on the receptor type and their potency. Three major types of receptors mediate analgesic effects, namely, mu (μ), delta (δ) and kappa (κ). These are also further subdivided into different subtypes depending on the duration and onset as rapid-onset, short-acting and long-acting. The neurobiology behind opioid analgesia involves the mesolimbic (midbrain) reward system. There is also increasing scientific evidence that plasma pharmacokinetics, along with the CNS distribution of opioids, is greatly influenced by the P-glycoprotein (P-gp) efflux transporter. The ABCB1 gene is responsible for coding P-gp hence it was postulated that variability in the ABCB1 gene could potentially play an important role in determining why there is interindividual variability towards opioids therapeutic interventionsHence the primary purpose of this review was to compile and understand the research regarding the mechanisms of opioid actions and the effect of genetic variability (ABCB1 gene), on the P-gp transporters regarding their expression/function while also examining the opioid use, abuse and dependence and possibly coming up with some strategies to use pharmacogenomics as a potential tool for solving these issues

The ability to measure traffic-speed tire-pavement noise in the laboratory is useful for predicting the tire-pavement noise performance of a design mix without conducting expensive and time-consumi...

Many-body excitations in X-ray photoemission spectra have been difficult to simulate from first principles. We have recently developed a cumulant-based one-electron Green's function method using the real-time coupled-cluster-singles equation-of-motion approach (RT-EOM-CCS) that provides a general framework for treating these problems. Here we extend this approach to include double excitations in the ground-state energy and in the coupled cluster amplitudes, which have been implemented using subroutines generated by the Tensor Contraction Engine (TCE). As in the case of the singles approximation, RT-EOM-CCSD yields a nonperturbative cumulant form of the Green's function in terms of the time-dependent cluster amplitudes, adding nonlinear corrections to the traditional cumulant forms. The extended approach is applied to the core-hole spectral function for small molecular systems. We find that, when core-optimized basis sets are used, the doubles contributions reduce the mean absolute errors in the core binding energies of the 10

In recent years, the continuous increase in wireless data services and users’ traffic demand has been imposing great challenges on traditional multiple access control (MAC) methods. Some existing MAC techniques improve the communication system’s spectral efficiency (SE) via signal processing based cochannel interference (CCI) management. However, no interference management (IM) is free, i.e., its realization is based on the consumption of some communication resources, such as power and degree-of-freedom (DoF), which can also be used for the user’s desired data transmission. To lessen the resource cost for IM-based MAC, we exploit interactions among multiple wireless signals to propose a new MAC method, namely, Differentiated Reception Modes based Multiple Access (DRM-MA), in this paper. Under DRM-MA, a central control unit (CCU) is adopted to manage and pair multiple transmitting antennas with their serving receivers (Rxs). The CCU first calculates the phase difference of signals sent from each candidate antenna and perceived by the two receiving antennas of an Rx based on the locations of the transmitting antenna and Rx. Then, the CCU selects and pairs a proper transmitting antenna with each Rx, so that various Rxs can adopt either additive or subtractive reception mode to postprocess the signals received by its two antennas to realize in-phase desired signal construction and inverse-phase interference destruction. DRM-MA can avoid transmission performance loss incurred by signal processing-based IM. Our theoretical analysis and simulation results have shown that DRM-MA can enable concurrent data transmissions of multiple antenna-receiver pairs and output a high system’s SE.