Estimation of future water resources of Xiangjiang River Basin with VIC model under multiple climate scenarios

Variation trends of water resources in the Xiangjiang River Basin over the coming decades have been investigated using the variable infiltration capacity(VIC) model and 14 general circulation models'(GCMs') projections under the representative concentration pathway(RCP4.5) scenario. Results show that the Xiangjiang River Basin will probably experience temperature rises during the period from 2021 to2050, with precipitation decrease in the 2020 s and increase in the 2030 s. The VIC model performs well for monthly discharge simulations with better performance for hydrometric stations on the main stream of the Xiangjiang River than for tributary catchments. The simulated annual discharges are significantly correlated to the recorded annual discharges for all the eight selected target stations. The Xiangjiang River Basin may experience water shortages induced by climate change. Annual water resources of the Xiangjiang River Basin over the period from 2021 to 2050 are projected to decrease by 2.76% on average within the range from-7.81% to 7.40%. It is essential to consider the potential impact of climate change on water resources in future planning for sustainable utilization of water resources.

Effects of welding parameters on weld shape and residual stresses in electron beam welded Ti_2AlNb alloy joints

In order to estimate the residual stresses in Ti2AlNb alloy jointed by electron beam welding (EBW), a computational approach based on finite element method was developed. Meanwhile, experiments were carried out to verify the numerical results. The comparison between the simulation results and measurements suggests that the developed computational approach has sufficient accuracy to predict the welding residual stress distributions. The results show that the central area of the fusion zone suffers tensile stresses in three directions. When the other parameters remain unchanged, the focus current has great impact on the weld shape and size, and then affects the residual stress level significantly. Moreover, the thick plate full-penetrated EBW weld suffers near 1000 MPa tensile stress of Z-direction in the center of the fusion zone. The wider weld has lower tensile stress in Z-direction, resulting in lower risk for cracking.

Effects of weld penetration on tensile properties of 2219 aluminum alloy TIG-welded joints

Numerical simulation and experimental methods were used to investigate the effects of weld penetration on tensile properties of 2219 aluminum alloy tungsten inert gas(TIG)welded joints.The results show that when other geometric parameters are consistent,within a certain range,the deeper the weld penetration of the capping weld is,the lower the tensile strength of the j oint is.The deeper weld penetration of the capping weld can cause the more concentrated stress at the weld toe and the joint is more likely to crack accordingly.Based on necessary assumptions,a model for analyzing the mathematical relation between the weld penetration of the capping weld and the tensile strength of the joint was proposed to validate the experimental results. The decrease of weld penetration of capping weld can be controlled by decreasing welding current,helium content or increasing welding voltage.

Mechanism of reheat cracking in electron beam welded Ti2Al Nb alloys

In order to clarify the characteristics and formation mechanism of the reheat cracking in Ti2AlNb weldments,a series of heat treatment conditions were performed to the circular joints welded by electron beam,and then the macrostructures and microstructures were investigated using optical microscopy,scanning electron microscopy,X-ray diffractometry,and transmission electron microscopy.The results show that the reheat cracking occurs primarily along the grain boundaries in the weld when the Ti2AlNb circular welded joints are heated up to about 700℃.During the heat treatment,an almost complete transformation of B2→O happens while the temperature goes up through the O single-phase region.Then,O→B2+O phase transformation occurs primarily along the grain boundaries as the weld metal continues to heat up to the B2+O dual-phase region.Under the high tension stress consisting of welding residual stress and phase transformation stress,reheat cracking occurs at the interface between the B2+O dual-phase layer and the O-phase matrix.

Early active immunization with Aβ3–10-KLH vaccine reduces tau phosphorylation in the hippocampus and protects cognition of mice

Active and passive anti-Aβimmunotherapies have successfully been used for the prevention and treatment of Alzheimer’s disease animal models.However,clinical use of these immunotherapies is not effective,because the vaccination is administered too late.At 1 month of age,100μL of Aβ3–10-KLH peptide(vaccine,2μg/μL)was subcutaneously injected into the neck of an amyloid precursor protein/presenilin-1/tau transgenic(3×Tg-AD)mouse model.Aβ3–10-KLH peptide was re-injected at 1.5,2.5,3.5,4.5,5.5,and 6.5 months of age.Serum levels of Aβantibody were detected by enzyme-linked immunosorbent assay,while spatial learning and memory ability were evaluated by Morris water maze.Immunohistochemistry was used to detect total tau with HT7 and phosphorylated tau with AT8(phosphorylation sites Ser202 and Thr205)and AT180(phosphorylation site Thr231)antibodies in the hippocampus.In addition,western blot analysis was used to quantify AT8 and AT180 expression in the hippocampus.The results showed that after vaccine injection,mice produced high levels of Aβantibody,cognitive function was significantly improved,and total tau and phosphorylated tau levels were significantly reduced.These findings suggest that early active immunization with Aβ3–10-KLH vaccine can greatly reduce tau phosphorylation,thereby mitigating the cognitive decline of 3×Tg-AD mice.This study was approved by the Animal Ethics Committee of China Medical University,China(approval No.103-316)on April 2,2016.

Evaluation of routine biopsies in endoscopic screening for esophagogastric junction cancer

AIM: To explore whether routine biopsies at the high incidence spot of esophagogastric junction (EGJ) cancer are justified in endoscopic screening.

Microstructural evolution and its effect on mechanical properties in different regions of 2219-C10S aluminum alloy TIG-welded joint

Microstructural evolution and its effect on mechanical properties in different regions of 2219-C10S aluminum alloy tungsten inert gas(TIG)welded joint were analyzed in detail.In weld zone(WZ),α+θeutectic structure formed at grain boundaries with no precipitates inside the grains.In partially melted zone(PMZ),symbiotic eutectic or divorced eutectic formed at grain boundaries and needle-likeθ′phases appeared in the secondary heated zone.In over aged zone(OAZ),the coarsening and dissolution ofθ′phases occurred and mostθ′phases transformed intoθphases.In general heat affected zone(HAZ),θ′phases coarsened.Factors such as the strengthening phases,the grain size,the Cu content in matrix and the dislocation density can affect the mechanical properties in different regions of the joint.Moreover,a model describing the relationship between mechanical properties of the material and the volume fraction of precipitates,the average diameter of precipitates and the concentration of soluble elements was proposed.

Necrostatin-1 decreases necroptosis and inflammatory markers after intraventricular hemorrhage in mice

Necrostatin-1,an inhibitor of necroptosis,can effectively inhibit necrotic apoptosis in neurological diseases,which results in the inhibition of inflammation,endoplasmic reticulum stress,and reactive oxygen species production and substantial improvement of neurological function.However,the effects of necrostatin-1 on intraventricular hemorrhage(IVH)remain unknown.In this study,we established a mouse model of IVH by injecting autologous blood into the lateral ventricle of the brain.We also injected necrostatin-1 into the lateral ventricle one hour prior to IVH induction.We found that necrostatin-1 effectively reduced the expression levels of the necroptosis markers receptor-interacting protein kinase(RIP)1,RIP3,mixed lineage kinase domain-like protein(MLKL),phosphorylated(p)-RIP3,and p-MLKL and the levels of interleukin-1β,interleukin-6,and tumor necrosis factor-αin the surrounding areas of the lateral ventricle.However,necrostatin-1 did not reduce ependymal ciliary injury or brain water content.These findings suggest that necrostatin-1 can prevent local inflammation and microglial activation induced by IVH but does not greatly improve prognosis.

Predicting a novel pathogenicity island in Helicobacter pylori by genomic barcoding

AIM:To apply a new,integrated technique for visualizing bacterial genomes to identify novel pathogenicity islands in Helicobacter pylori(H.pylori).METHODS:A genomic barcode imaging method(converting frequency matrices to grey-scale levels)was designed to visually distinguish origin-specific genomic regions in H.pylori.The complete genome sequences of the six H.pylori strains published in the National Center for Biotechnological Information prokaryotic genome database were scanned,and compared to the genome barcodes of Escherichia coli(E.coli)O157:H7 strain EDL933 and a random nucleotide sequence.The following criteria were applied to identify potential pathogenicity islands(PAIs):(1)barcode distance distinct from that of the general background;(2)length greater than 10000 continuous base pairs;and(3)containing genes with known virulence-related functions(as determined by PfamScan and Blast2GO).RESULTS:Comparison of the barcode images generated for the 26695,HPAG1,J99,Shi470,G27 and P12 H.pylori genomes with those for the E.coli and random sequence controls revealed that H.pylori genomes contained fewer anomalous regions.Among the H.pylorispecific continuous anomalous regions(longer than 20 kbp in each strain's genome),two fit the criteria for identifying candidate PAIs.The bioinformatic-based functional analyses revealed that one of the two anomalous regions was the known pathogenicity island cag PAI,this finding also served as proof-of-principle for the utility of the genomic barcoding approach for identifying PAIs,and characterized the other as a novel PAI,which was designated as tfs3-PAI.Furthermore,the cag-PAI and tfs3-PAI harbored genes encoding type IV secretion system proteins and were predicted to have potential for functional synergy.CONCLUSION:Genomic barcode imaging represents an effective bioinformatic-based approach for scanning bacterial genomes,such as H.pylori,to identify candidate PAIs.

Computational prediction and experimental validation of novel markers for detection of STEC O157:H7

AIM:To identify and assess the novel makers for detection of Shiga toxin producing Escherichia coli (STEC) O157:H7 with an integrated computational and experimental approach. METHODS:High-throughput NCBI blast (E-value cutoff e-5) was used to search homologous genes among all sequenced prokaryotic genomes of each gene encoded in each of the three strains of STEC O157:H7 with complete genomes,aiming to find unique genes in O157:H7 as its potential markers. To ensure that the identified markers from the three strains of STEC O157:H7 can serve as general markers for all the STEC O157:H7 strains,a genomic barcode approach was used to select the markers to minimize the possibility of choosing a marker gene as part of a transposable element. Effectiveness of the markers predicted was then validated by running polymerase chain reaction (PCR) on 18 strains of O157:H7 with 5 additional genomes used as negative controls. RESULTS:The blast search identified 20,16 and 20 genes,respectively,in the three sequenced strains of STEC O157:H7,which had no homologs in any of the other prokaryotic genomes. Three genes,wzy,Z0372 and Z0344,common to the three gene lists,were selected based on the genomic barcode approach. PCR showed an identification accuracy of 100% on the 18 tested strains and the 5 controls. CONCLUSION:The three identified novel markers,wzy,Z0372 and Z0344,are highly promising for the detection of STEC O157:H7,in complementary to the known markers.

The status of caregiver burden and influencing factors among family caregivers in maintenance hemodialysis patients

Objective: To investigate the status of caregiver burden and influencing factors among family caregivers in maintenance hemodialysis (MHD) patients under the background of coronavirus disease 2019, and to provide references for nursing intervention. Methods: From May to August 2020, 237 convenient samples were recruited from the Hemodialysis Centers of The Renmin Hospital of Wuhan University and Zhongnan Hospital of Wuhan University. Questionnaires were conducted with the General Information Questionnaire, Zarit Burden Interview (ZBI), Sense of Coherence-13 (SOC-13) and Perceived Social Support Scale (PSSS). Multiple linear regression was used to analyze the influencing factors of caregiver burden. Results: The score of ZBI among the caregivers was (36.05 ± 14.09). The ZBI of family caregivers was negatively correlated with SOC-13 and PSSS (P < 0.01). Multiple regression results showed that professional status of MHD patients, activity of MHD patients, comprehensibility, manageability and other support were the main influencing factors of their caregiver burden (P < 0.01), which explained 44.4% of the variance. Conclusion: The caregiver burden among family caregivers of MHD patients was above average under the background of COVID-19, which indicated that they felt more burden in the process of caring. Medical staff could give targeted support and guidance in combination with their influencing factors to reduce their caregiver burden further.

Research Progress of Bobbin Tool Friction Stir Welding of Aluminum Alloys:A Review

Bobbin tool friction stir welding(BT-FSW)is a variant of conventional friction stir welding(FSW).It can be used to weld complex curvature structures and closed sections by adding an extra shoulder instead of a rigid backing anvil,which expands the potential application of FSW in aerospace,railway,automotive and marine industries.BT-FSW has some signifi cant advantages over conventional FSW such as no root fl aws,full weld penetration,low stiff ness requirements for machines and fi xtures,balanced heat input,lower distortion and thus has broad prospects for development.At present,there have been numerous research reports on BT-FSW,but its widespread use is still restricted due to various factors such as tool life,process stability,control complexity and implementation cost.In this paper,the domestic and foreign research progress of BT-FSW is reviewed from four aspects of bobbin tool design and classifi cation,temperature fi eld and fl ow fi eld during welding,microstructure and mechanical properties of welded joints as well as industrial application,and then the possible research hotspots of BT-FSW in the future are pointed out.This paper mainly aims to help researchers have a comprehensive and in-depth understanding of BT-FSW.

Effects of Post-weld Heat Treatment on Microstructure, Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state,each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases.After the post-weld heat treatment,both the amount and the size of the eutectic structure orθphases decreased.Correspondingly,both the Cu content inα-Al matrix and the microhardness increased to a similar level in each region of the joint,and the tensile strength of the entire joint was greatly improved.Post-weld heat treatment played the role of solid solution strengthening and aging strengthening.After the post-weld heat treatment,the weld performance became similar to other regions,but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect.The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties,and the specimens randomly crack in the weld zone.

A Pilot Study of Quantitative Loop-mediated Isothermal Amplification-guided Target Therapies for Hospital-acquired Pneumonia

Background： It is important to achieve the definitive pathogen identification in hospital-acquired pneumonia （HAP）, but the traditional culture results always delay the target antibiotic therapy. We assessed the method called quantitative loop-mediated isothermal amplification （qLAMP） as a new implement for steering of the antibiotic decision-making in HAP. Methods： Totally, 76 respiratory tract aspiration samples were prospectively collected from 60 HAP patients. DNA was isolated from these samples. Specific DNA fragments for identifying 11 pneumonia-related bacteria were amplified by qLAMP assay. Culture results of these patients were compared with the qLAMP results. Clinical data and treatment strategies were analyzed to evaluate the effects of qLAMP results on clinical data. McNemar test and Fisher＇s exact test were used for statistical analysis. Results： The detection of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Stenotrophomonas maltophilia, Streptococcus pneumonia, and Acinetobacter baumannii by qLAMP was consistent with sputum culture （P 〉 0.05）. The qLAMP results of 4 samples for Haemophilus influenzae, Legionella pneumophila, or Mvcoplasma pneumonia （MP） were inconsistent with culture results; however, clinical data revealed that the qLAMP results were all reliable except 1 MP positive sample due to the lack of specific species identified in the final diagnosis. The improvement of clinical condition was more significant （P 〈 0.001） in patients with pathogen target-driven therapy based on qLAMP results than those with empirical therapy. Conclusion： qLAMP is a more promising method for detection of pathogens in an early, rapid, sensitive, and specific manner than culture.

Longitudinal dynamics of antibody responses in recovered COVID-19 patients

Dear Editor,The coronavirus disease 2019(COVID-19)has resulted in more than 66.5 million cases globally in more than 191 countries with overl,529,000 mortalities as of 6 December.Currently,the COVID-19 continued to spread around the world,while the duration of antibody lasts and antibody level remained poorly understood,which are primary for safe and effective antiviral treatments and vaccines in the future.In this study,we comprehensively characterized the longitudinal changes of antibodies in recovered patients from 5-7 to 34-42 weeks after symptom onset.