BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneum...BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneumoniae infections(KPIs)in the bloodstream are common in LT recipients.We hypothesized that KPIs and carbapenemresistant Klebsiella pneumoniae(CRKP)infections may affect the outcomes of LT recipients.AIM To assess KPI incidence,timing,distribution,drug resistance,and risk factors following LT and its association with outcomes.METHODS This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University,a tertiary hospital,from January 2015 to January 2023.We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.RESULTS KPI incidence was 7.9%(n=32),with lung/thoracic cavity the most frequent site of infection;the median time from LT to KPI onset was 7.5 d.Of 44 Klebsiella pneumoniae isolates,43(97.7%)and 34(77.3%)were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline,respectively;>70%were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin.Female sex[odds ratio(OR)=2.827,95%confidence interval(CI):1.256-6.364;P=0.012],pre-LT diabetes(OR=2.794,95%CI:1.070-7.294;P=0.036),day 1 post-LT alanine aminotransferase(ALT)levels≥1500 U/L(OR=3.645,95%CI:1.671-7.950;P=0.001),and post-LT urethral catheter duration over 4 d(OR=2.266,95%CI:1.016-5.054;P=0.046)were risk factors for KPI.CRKP infections,but not KPIs,were risk factors for 6-month all-cause mortality post-LT.CONCLUSION KPIs occur frequently and rapidly after LT.Risk factors include female sex,pre-LT diabetes,increased post-LT ALT levels,and urethral catheter duration.CRKP infections,and not KPIs,affect mortality.展开更多
The traces left by earthquakes in lacustrine sediments are studied to determine the occurrence of ancient earthquakes by identifying seismically induced soft-sediment deformation structures(SSDS).Dating can help recon...The traces left by earthquakes in lacustrine sediments are studied to determine the occurrence of ancient earthquakes by identifying seismically induced soft-sediment deformation structures(SSDS).Dating can help reconstruct the relative frequency of earthquakes.Identifying seismically induced seismites,which carry abundant seismic information from numerous SSDS,is both critical and challenging.Studying the deformation mechanism of SSDS and learning about the common criteria of seismically induced SSDS improve the identification of earthquake triggers.With better research into SSDS,seismic events can be effectively captured,and temporal constraints can be carried out by 14C dating and optically stimulated luminescence(OSL)dating to identify and date the occurrence of ancient earthquakes.The present contribution primarily addresses the meaning and mechanism of SSDS and their relationship with earthquake magnitude as well as the common criteria of the SSDS induced by earthquakes.展开更多
目的:探讨糖尿病视网膜病变(DR)患者全视网膜激光光凝术(PRP)术后预后相关影响因素。方法:收集2015-09/2017-09来我院就诊的DR患者182例301眼,根据病变分期给予患者不同的治疗方式,增殖前期患者进行次全视网膜光凝治疗,DR增殖早期患者...目的:探讨糖尿病视网膜病变(DR)患者全视网膜激光光凝术(PRP)术后预后相关影响因素。方法:收集2015-09/2017-09来我院就诊的DR患者182例301眼,根据病变分期给予患者不同的治疗方式,增殖前期患者进行次全视网膜光凝治疗,DR增殖早期患者进行标准全视网膜光凝治疗,高危患者进行超全视网膜光凝治疗。对患者随访6mo,记录患者的预后情况,筛选对视力变化有影响的相关因素。结果:对单因素有意义的因素进行多因素Logistic回归分析可以得出,年龄、初诊视力、低密度脂蛋白胆固醇、总胆固醇、甘油三酯、高密度脂蛋白胆固醇、糖化血红蛋白、黄斑水肿严重程度、血压与预后具有相关性( P <0.05)。结论:高血压、年龄大、高血脂、初诊视力差、糖化血红蛋白水平高、黄斑水肿严重对DR患者激光光凝术后的预后造成一定影响。展开更多
In contrast to conventional gas-bearing rocks, gas shale has extremely low permeability due to its nano- scale pore networks. Organic matter which is dispersed in the shale matrix makes gas flow characteristics more c...In contrast to conventional gas-bearing rocks, gas shale has extremely low permeability due to its nano- scale pore networks. Organic matter which is dispersed in the shale matrix makes gas flow characteristics more complex. The traditional Darcy＇s law is unable to estimate matrix permeability due to the particular flow mechanisms of shale gas. Transport mechanisms and influence factors are studied to describe gas transport in extremely tight shale. Then Lattice Boltzmann simulation is used to establish a way to estimate the matrix permeability numerically. The results show that net desorption, diffu- sion, and slip flow are very sensitive to the pore scale. Pore pressure also plays an important role in mass fluxes of gas. Temperature variations only cause small changes in mass fluxes. The Lattice Boltzmann method can be used to study the flow field in the micropore spaces and then provides numerical solutions even in complex pore structure models. Understanding the transport characteristics and establishing a way to estimate potential gas flow is very important to guide shale gas t＇eserve estimation and recovery schemes.展开更多
Objective To assese the healing of stoma after magnetic anastomosis for the reconstruction of biliary-enteric continuity under severe inflammation. Methods Acute bile duct injury was constructed as a bile peritonitis ...Objective To assese the healing of stoma after magnetic anastomosis for the reconstruction of biliary-enteric continuity under severe inflammation. Methods Acute bile duct injury was constructed as a bile peritonitis model in mongrel dogs(n=32). Magnetic anastomosis(group A, n=16) and traditional suture anastomosis(group B, n=16) were performed to reconstruct the biliary-enteric continuity in one stage. Half of the dogs in each group were euthanized on the 30 th postoperative day, and the other half on the 90 th postoperative day to harvest the stoma region. The healing conditions of the stoma after the 2 anastomotic approaches were observed with naked eyes, under light microscope and scanning electron microscope. Results The stoma leakage rate(50% versus 0% on the 30 th postoperative day, 37.5% versus 12.5% on the 90 th postoperative day, both P<0.05) and stenosis degree(13.9%±0.3% versus 7.1%±0.3% on the 30 th postoperative day, 17.2%±0.4% versus 9.4%±0.4% on the 90 th postoperative day, both P<0.01) were significantly higher in group B than in group A. Compared with traditional manual anastomoses, the histological analysis under light and electron microscope showed a more continuous stoma with more regular epithelium proliferation and collagen arrangement, less inflammation in group A. Conclusions Magnetic anastomosis stent ensures better healing of the stoma even under the circumstance of severe inflammation.展开更多
Under the background of“Internet plus”rapid development,the agricultural logistics industry should apply information technology to every link of the agricultural product logistics industry chain.By making full use o...Under the background of“Internet plus”rapid development,the agricultural logistics industry should apply information technology to every link of the agricultural product logistics industry chain.By making full use of the decision making module of the agricultural logistics information system,we can realize the full sharing of information and data resources,which makes the decision-making scheme of the agricultural logistics information system more optimized.In real economic society,the uncertainty and mismatch between the customer’s logistics service demand and the logistics service capability that the logistics service function provider can provide,that is,when the two information are asymmetric,how to use the third-party contract to coordinate the income and profit distribution of the two,to make the information system decision making more reasonable?This paper mainly studies the coordination scheme of agricultural logistics information system decision making under uncertain output and demand information by introducing the spot market.A joint coordination strategy based on revenue sharing and penalty feedback contracts proposes decentralized decision making based on game theory.Experiments show that the flexible ordering strategy proposed in this paper can reduce the logistics service supply chain’s uncertainty and significantly improve the logistics service supply chain’s overall income level through coordination contracts.展开更多
The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of mi...The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.展开更多
Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve ...Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve this,we briefly investigated 158 P.multocida isolates from pigs with respiratory disorders in China between 2019 and 2020.Genotyping through multiplex PCR assays assigned these 158 isolates into capsular genotypes A(60.13%,95/158),D(35.44%,56/158),F(4.43%,7/158),and/or lipopolysaccharide(LPS)genotypes L3(28.48%,45/158)and L6(66.46%,105/158).In addition,eight isolates(5.06%,8/158)were found to be nontypable using the LPS genotyping method.When combining the capsular genotypes and the LPS genotypes,D:L6(34.81%,55/158)and A:L6(31.65%,50/158)were the predominant genotypes,followed by A:L3(24.05%,38/158).PCR detection of virulence factor-encoding genes showed that over 80%of the isolates were positive for exbB,tonB,exbD,ompH,ptfA,fimA,sodA,sodC,fur,ompA,oma87,plpB,hsf-2,nanH and hgbB,suggesting the presence of these genes were broad characteristics of P.multocida.We also found approximately 63.92%(101/158),51.27%(81/158),8.86%(14/158),7.59%(12/158),3.16%(5/158),0.63%(1/158),and 0.63%(1/158)of the isolates grew well in media with the presence of colistin(4μg/mL),tetracycline(16μg/mL),tigecycline(1μg/mL),ampicillin(32μg/mL),chloramphenicol(32μg/mL),cefepime(16μg/mL),and ciprofloxacin(1μg/mL),respectively.This study contributes to the understanding of genotypes and antimicrobial resistance profile of P.multocida currently circulation in pigs of China.展开更多
It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge(SOC) estimation, and the accurate SOC estimation is a significant issue for devel...It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge(SOC) estimation, and the accurate SOC estimation is a significant issue for developing the battery management system in electric vehicles. To address this problem, in this paper we propose an enhanced equivalent circuit model(ECM) considering the influence of different ambient temperatures on the open-circuit voltage for a lithium-ion battery. Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. And then, the extended Kalman filter(EKF) algorithm is employed to estimate the battery SOC of this battery ECM. The performance of the proposed ECM is verified by using the test profiles of hybrid pulse power characterization(HPPC) and the standard US06 driving cycles(US06) at various ambient temperatures, and by comparing with the common ECM with a second-order resistance capacitor. The simulation and experimental results show that the enhanced battery ECM can improve the battery SOC estimation accuracy under different operating conditions.展开更多
Urban water supply network is a modern urban survival and development of the infrastructure of a city,and its normal running conditions have important significance. The actual hydraulic process in the variableload wat...Urban water supply network is a modern urban survival and development of the infrastructure of a city,and its normal running conditions have important significance. The actual hydraulic process in the variableload water distribution networks can be treated as the slow transient flow which belongs to the unsteady flow. This paper analyzes the multi-loops network slow transient model based on graph theory,and the link flow matrix is treated as the variables of the discrete solution model to simulate the process of the slow transient flow in the network. With the simulation of hydraulic regime in an actual pipe network,the changing laws of the flow in the pipes,nodal hydraulic heads and other hydraulic factors with the passage of time are obtained. Since the transient processes offer much more information than a steady process,the slow transient theory is not only practical on analyzing the hydraulic condition of the network,but also on identifying hydraulic resistance coefficients of pipes and detecting the leakage in networks.展开更多
背景与目的:腹腔镜右半肝切除术(LRH),是难度较大的微创肝切除手术,需要较长的学习曲线。传统的LRH操作秉承了开放肝切除“肝蒂优先,鞘内解剖”的操作习惯,即在切除胆囊后先游离右肝动脉、右门静脉、右胆管,分别离断后再行肝实质离断。...背景与目的:腹腔镜右半肝切除术(LRH),是难度较大的微创肝切除手术,需要较长的学习曲线。传统的LRH操作秉承了开放肝切除“肝蒂优先,鞘内解剖”的操作习惯,即在切除胆囊后先游离右肝动脉、右门静脉、右胆管,分别离断后再行肝实质离断。但它耗时费力,如操作不当,有出血风险。笔者在前期临床工作中摸索出了优先解剖肝实质再处理目标肝蒂的入肝血流阻断技术,将其命名为“肝实质解剖优先法”(LPDF)。这一方法未改变手术切除范围,仅调整了操作顺序,初步经验提示其可简化半肝切除手术流程,有利于LRH的推广应用。本研究进一步探讨LPDF相对于肝蒂优先法在LRH中的优势。方法:采用前瞻性研究方法,将2021年8月—2023年8月在中南大学湘雅医院行LRH且符合标准的肝癌患者随机分为观察组和对照组,观察组术中采用LPDF,对照组则采用肝蒂优先法。收集并比较两组患者围术期临床指标。结果:共纳入19例患者,其中观察组10例,对照组9例。两组患者的基线资料差异无统计学意义(均P>0.05)。观察组的手术时间明显少于对照组(224.30 min vs.267.78 min,P=0.045),两组其余指标包括术中出血量和输血量、中转开腹率、术后排气时间、住院时间、术后第3天肝功能、并发症发生率,以及无复发生存率与总生存率差异均无统计学意义(均P>0.05)。结论:LPDF应用于LRH相较于传统的肝蒂优先法简化了肝蒂处理流程,缩短了手术时间,未增加术后并发症发生率,且一定程度上减少了出血风险,建议行进一步大样本量研究与推广。展开更多
Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization...Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization practices in acidic soils are poorly studied.Here,we conducted a long-term(29 years)fertilization experiment to explore how fertilization affected free-living BNF via changing biotic and abiotic variables.The fertilization treatments included an unfertilized control(CK),chemical N,phosphorus(P),and potassium(K)fertilizers(NPK),NPK plus lime(NPKL),NPK plus straw(NPKS),NPK plus straw and lime(NPKSL),and NPK plus manure(NPKM).Compared with CK(1.51 nmol C_(2)H_(2)g^(-1)d^(-1)),BNF rate was significantly(P<0.05)higher in NPKM(1.99 nmol C_(2)H_(2)g^(-1)d^(-1))but lower in NPK(0.55 nmol C_(2)H_(2)g^(-1)d^(-1)),NPKL(0.61 nmol C_(2)H_(2)g^(-1)d^(-1)),and NPKS(0.69nmol C_(2)H_(2)g^(-1)d^(-1)).Similarly,chemical fertilization treatments without manure reduced the gene abundance(0.71×10^(8)-1.18×10^(8)copies g^(-1))andα-diversity(Shannon index,1.11-2.43)of diazotrophic communities,whereas the treatment with manure had a positive effect on diazotrophic abundance(3.23×10^(8)copies g^(-1))and Shannon index(3.36).Non-parametric multivariate analysis of variance(PERMANOVA)suggested that manure application(R^(2)=0.212,P=0.001)had a stronger influence on diazotrophic community composition than the addition of lime(R^(2)=0.115,P=0.019)or straw(R^(2)=0.064,P=0.161).Random forest modeling revealed that BNF rates can be significantly(P<0.05)explained by soil pH(9.9%),diazotrophic community attributes(composition,8.5%;Chao 1 index,8.1%;abundance,6.0%;Shannon index,5.7%),and soil total carbon(5.1%).Partial least squares path modeling(PLS-PM)suggested that the diazotrophic community attributes and soil properties mainly provided direct and indirect contributions to the variations in BNF rates,respectively.The dominant genera,Pelomonas,Azospirillum,and Dechloromonas,were positively associated with BNF rates,with their members being observed as keystone species in the community network.Application of chemical fertilizers combined with manure is an effective practice for improving BNF in acidic soils by affecting soil diazotrophic communities.展开更多
Mechanical properties and creep behavior of Q460E continuous casting slab were studied by means of uniaxial tensile tests on a Gleeble-3800 thermomechanical simulator from 1000 to 1100 ℃.The high-temperature creep co...Mechanical properties and creep behavior of Q460E continuous casting slab were studied by means of uniaxial tensile tests on a Gleeble-3800 thermomechanical simulator from 1000 to 1100 ℃.The high-temperature creep constitutional equation was derived based on experimental data.The parameters in the equation were calculated by using the regression analysis inverse-estimation method.The experimental curves in the primary and secondary creep stages are fitted well.A three-dimensional elastic-plastic and creep finite element model was proposed in order to investigate the bulging deformation of slab and the bulging deformation at the beginning position of bending segment on the slab continuous casting machine was computed accurately.The results indicate that the maximum bulging deformation appears at the geometric center of the slab.The maximum value of the bulging deformation obtained by the elastic-plastic analysis is 1.301 ram.Consideririg the creep effect,the deformation increases to 1.827 mm which is about 1.4 times the value obtained by the elastic-plastic analysis.The calculation of buleing deformation usin2 the elastic-plastic creed model is more reliable and/iccurate.展开更多
基金approved by the Ethics Committee of the Third Xiangya Hospital in accordance with the Declaration of Helsinki(No.24029).
文摘BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneumoniae infections(KPIs)in the bloodstream are common in LT recipients.We hypothesized that KPIs and carbapenemresistant Klebsiella pneumoniae(CRKP)infections may affect the outcomes of LT recipients.AIM To assess KPI incidence,timing,distribution,drug resistance,and risk factors following LT and its association with outcomes.METHODS This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University,a tertiary hospital,from January 2015 to January 2023.We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.RESULTS KPI incidence was 7.9%(n=32),with lung/thoracic cavity the most frequent site of infection;the median time from LT to KPI onset was 7.5 d.Of 44 Klebsiella pneumoniae isolates,43(97.7%)and 34(77.3%)were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline,respectively;>70%were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin.Female sex[odds ratio(OR)=2.827,95%confidence interval(CI):1.256-6.364;P=0.012],pre-LT diabetes(OR=2.794,95%CI:1.070-7.294;P=0.036),day 1 post-LT alanine aminotransferase(ALT)levels≥1500 U/L(OR=3.645,95%CI:1.671-7.950;P=0.001),and post-LT urethral catheter duration over 4 d(OR=2.266,95%CI:1.016-5.054;P=0.046)were risk factors for KPI.CRKP infections,but not KPIs,were risk factors for 6-month all-cause mortality post-LT.CONCLUSION KPIs occur frequently and rapidly after LT.Risk factors include female sex,pre-LT diabetes,increased post-LT ALT levels,and urethral catheter duration.CRKP infections,and not KPIs,affect mortality.
基金the National Institute of Natural Hazards,Ministry of Emergency Management of China(ZDJ2019-21)the National Natural Science Foundation of China(Nos.41872227 and 41602221).
文摘The traces left by earthquakes in lacustrine sediments are studied to determine the occurrence of ancient earthquakes by identifying seismically induced soft-sediment deformation structures(SSDS).Dating can help reconstruct the relative frequency of earthquakes.Identifying seismically induced seismites,which carry abundant seismic information from numerous SSDS,is both critical and challenging.Studying the deformation mechanism of SSDS and learning about the common criteria of seismically induced SSDS improve the identification of earthquake triggers.With better research into SSDS,seismic events can be effectively captured,and temporal constraints can be carried out by 14C dating and optically stimulated luminescence(OSL)dating to identify and date the occurrence of ancient earthquakes.The present contribution primarily addresses the meaning and mechanism of SSDS and their relationship with earthquake magnitude as well as the common criteria of the SSDS induced by earthquakes.
文摘目的:探讨糖尿病视网膜病变(DR)患者全视网膜激光光凝术(PRP)术后预后相关影响因素。方法:收集2015-09/2017-09来我院就诊的DR患者182例301眼,根据病变分期给予患者不同的治疗方式,增殖前期患者进行次全视网膜光凝治疗,DR增殖早期患者进行标准全视网膜光凝治疗,高危患者进行超全视网膜光凝治疗。对患者随访6mo,记录患者的预后情况,筛选对视力变化有影响的相关因素。结果:对单因素有意义的因素进行多因素Logistic回归分析可以得出,年龄、初诊视力、低密度脂蛋白胆固醇、总胆固醇、甘油三酯、高密度脂蛋白胆固醇、糖化血红蛋白、黄斑水肿严重程度、血压与预后具有相关性( P <0.05)。结论:高血压、年龄大、高血脂、初诊视力差、糖化血红蛋白水平高、黄斑水肿严重对DR患者激光光凝术后的预后造成一定影响。
基金supported by the National Natural Science Foundation of China(Grant No.41130417)‘‘111 Program’’(B13010)Shell Ph.D.Scholarship
文摘In contrast to conventional gas-bearing rocks, gas shale has extremely low permeability due to its nano- scale pore networks. Organic matter which is dispersed in the shale matrix makes gas flow characteristics more complex. The traditional Darcy＇s law is unable to estimate matrix permeability due to the particular flow mechanisms of shale gas. Transport mechanisms and influence factors are studied to describe gas transport in extremely tight shale. Then Lattice Boltzmann simulation is used to establish a way to estimate the matrix permeability numerically. The results show that net desorption, diffu- sion, and slip flow are very sensitive to the pore scale. Pore pressure also plays an important role in mass fluxes of gas. Temperature variations only cause small changes in mass fluxes. The Lattice Boltzmann method can be used to study the flow field in the micropore spaces and then provides numerical solutions even in complex pore structure models. Understanding the transport characteristics and establishing a way to estimate potential gas flow is very important to guide shale gas t＇eserve estimation and recovery schemes.
基金Supported by the National Natural Science Foundation of China(30830099)China Postdoctoral Science Foundation(20100481341)Scienceand Technology Research and Development Project of Shaanxi Province(2009K14-01)
文摘Objective To assese the healing of stoma after magnetic anastomosis for the reconstruction of biliary-enteric continuity under severe inflammation. Methods Acute bile duct injury was constructed as a bile peritonitis model in mongrel dogs(n=32). Magnetic anastomosis(group A, n=16) and traditional suture anastomosis(group B, n=16) were performed to reconstruct the biliary-enteric continuity in one stage. Half of the dogs in each group were euthanized on the 30 th postoperative day, and the other half on the 90 th postoperative day to harvest the stoma region. The healing conditions of the stoma after the 2 anastomotic approaches were observed with naked eyes, under light microscope and scanning electron microscope. Results The stoma leakage rate(50% versus 0% on the 30 th postoperative day, 37.5% versus 12.5% on the 90 th postoperative day, both P<0.05) and stenosis degree(13.9%±0.3% versus 7.1%±0.3% on the 30 th postoperative day, 17.2%±0.4% versus 9.4%±0.4% on the 90 th postoperative day, both P<0.01) were significantly higher in group B than in group A. Compared with traditional manual anastomoses, the histological analysis under light and electron microscope showed a more continuous stoma with more regular epithelium proliferation and collagen arrangement, less inflammation in group A. Conclusions Magnetic anastomosis stent ensures better healing of the stoma even under the circumstance of severe inflammation.
基金The Agricultural Science and Technology Innovation Program(ASTIP-IAED-2021-08).
文摘Under the background of“Internet plus”rapid development,the agricultural logistics industry should apply information technology to every link of the agricultural product logistics industry chain.By making full use of the decision making module of the agricultural logistics information system,we can realize the full sharing of information and data resources,which makes the decision-making scheme of the agricultural logistics information system more optimized.In real economic society,the uncertainty and mismatch between the customer’s logistics service demand and the logistics service capability that the logistics service function provider can provide,that is,when the two information are asymmetric,how to use the third-party contract to coordinate the income and profit distribution of the two,to make the information system decision making more reasonable?This paper mainly studies the coordination scheme of agricultural logistics information system decision making under uncertain output and demand information by introducing the spot market.A joint coordination strategy based on revenue sharing and penalty feedback contracts proposes decentralized decision making based on game theory.Experiments show that the flexible ordering strategy proposed in this paper can reduce the logistics service supply chain’s uncertainty and significantly improve the logistics service supply chain’s overall income level through coordination contracts.
基金This work was supported by the National Natural Science Foundation of China(No.51671105,51705244)Natural Science Foundation of Jiangsu Province(No.BK20170790)+2 种基金the Project Funded by China Postdoctoral Science Foundation(No.2019M661826)Fund of State Key Laboratory of Aerodynamics(SKLA2019020401)Open Fund of Key Laboratory of Icing and Anti/De-icing(No.IADL20190202).
文摘The aim of this study is to explore the heterogeneous ice nucleation behavior based on controllable micro-cubic array structure surfaces from the statistic perspective.To this end,we firstly constructed a group of micro-cubic array structures on silicon substrates by a selective plasma etching technique.After grafting low-free-energy substance,the as-constructed micro-cubic array structure surfaces exhibited higher non-wettability with the water contact angle being up to 150°.On this basis,500 cycles of freezing and melting processes were accurately recorded to analyze the instantaneous ice nucleation behavior according to the statistical results of freezing temperature.As a consequence,the statistical freezing temperature of the sample with micro-spacing distance of 40μm is as low as−17.13°C.This microstructure configuration(conforming to Cassie-Baxter wetting regime)not only could entrap more air pockets,but also achieved lower solid-liquid contact area,resulting in lower ice nucleation rate(~2–3 orders of magnitude less than that on the flat substrate).Furthermore,the gradually increasing micro-spacing distance to 60μm would induce the transition from CassieBaxter to Wenzel wetting state,leading to higher freezing probability and ice nucleation rate.The complete understanding on microstructure configuration improving the ice nucleation will lay the foundation stone for the microstructure design of ice-repellent materials.
基金This work was supported in part by the China Postdoctoral Foundation(grant 2020 T130232)the Key Laboratory of Livestock Disease Prevention of Guangdong Province and the Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province,Ministry of Agriculture and Rural Affairs,China(grant YDWS1901)Hubei Provincial Key R&D program.The funder had no role in the study design,data collection,data analysis,data interpretation,or writing of the manuscript.
文摘Pasteurella multocida is a leading cause of respiratory disorders in pigs.This study was designed to understand the genotypical and antimicrobial resistant characteristics of P.multocida from pigs in China.To achieve this,we briefly investigated 158 P.multocida isolates from pigs with respiratory disorders in China between 2019 and 2020.Genotyping through multiplex PCR assays assigned these 158 isolates into capsular genotypes A(60.13%,95/158),D(35.44%,56/158),F(4.43%,7/158),and/or lipopolysaccharide(LPS)genotypes L3(28.48%,45/158)and L6(66.46%,105/158).In addition,eight isolates(5.06%,8/158)were found to be nontypable using the LPS genotyping method.When combining the capsular genotypes and the LPS genotypes,D:L6(34.81%,55/158)and A:L6(31.65%,50/158)were the predominant genotypes,followed by A:L3(24.05%,38/158).PCR detection of virulence factor-encoding genes showed that over 80%of the isolates were positive for exbB,tonB,exbD,ompH,ptfA,fimA,sodA,sodC,fur,ompA,oma87,plpB,hsf-2,nanH and hgbB,suggesting the presence of these genes were broad characteristics of P.multocida.We also found approximately 63.92%(101/158),51.27%(81/158),8.86%(14/158),7.59%(12/158),3.16%(5/158),0.63%(1/158),and 0.63%(1/158)of the isolates grew well in media with the presence of colistin(4μg/mL),tetracycline(16μg/mL),tigecycline(1μg/mL),ampicillin(32μg/mL),chloramphenicol(32μg/mL),cefepime(16μg/mL),and ciprofloxacin(1μg/mL),respectively.This study contributes to the understanding of genotypes and antimicrobial resistance profile of P.multocida currently circulation in pigs of China.
基金Project supported by the National Natural Science Foundation of China(Grant No.51675423)
文摘It is widely accepted that the variation of ambient temperature has great influence on the battery model parameters and state-of-charge(SOC) estimation, and the accurate SOC estimation is a significant issue for developing the battery management system in electric vehicles. To address this problem, in this paper we propose an enhanced equivalent circuit model(ECM) considering the influence of different ambient temperatures on the open-circuit voltage for a lithium-ion battery. Based on this model, the exponential-function fitting method is adopted to identify the battery parameters according to the test data collected from the experimental platform. And then, the extended Kalman filter(EKF) algorithm is employed to estimate the battery SOC of this battery ECM. The performance of the proposed ECM is verified by using the test profiles of hybrid pulse power characterization(HPPC) and the standard US06 driving cycles(US06) at various ambient temperatures, and by comparing with the common ECM with a second-order resistance capacitor. The simulation and experimental results show that the enhanced battery ECM can improve the battery SOC estimation accuracy under different operating conditions.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50908064 and 51208158)the 46thChina Postdoctoral Science Foundation(Grant No.20090460912)
文摘Urban water supply network is a modern urban survival and development of the infrastructure of a city,and its normal running conditions have important significance. The actual hydraulic process in the variableload water distribution networks can be treated as the slow transient flow which belongs to the unsteady flow. This paper analyzes the multi-loops network slow transient model based on graph theory,and the link flow matrix is treated as the variables of the discrete solution model to simulate the process of the slow transient flow in the network. With the simulation of hydraulic regime in an actual pipe network,the changing laws of the flow in the pipes,nodal hydraulic heads and other hydraulic factors with the passage of time are obtained. Since the transient processes offer much more information than a steady process,the slow transient theory is not only practical on analyzing the hydraulic condition of the network,but also on identifying hydraulic resistance coefficients of pipes and detecting the leakage in networks.
文摘背景与目的:腹腔镜右半肝切除术(LRH),是难度较大的微创肝切除手术,需要较长的学习曲线。传统的LRH操作秉承了开放肝切除“肝蒂优先,鞘内解剖”的操作习惯,即在切除胆囊后先游离右肝动脉、右门静脉、右胆管,分别离断后再行肝实质离断。但它耗时费力,如操作不当,有出血风险。笔者在前期临床工作中摸索出了优先解剖肝实质再处理目标肝蒂的入肝血流阻断技术,将其命名为“肝实质解剖优先法”(LPDF)。这一方法未改变手术切除范围,仅调整了操作顺序,初步经验提示其可简化半肝切除手术流程,有利于LRH的推广应用。本研究进一步探讨LPDF相对于肝蒂优先法在LRH中的优势。方法:采用前瞻性研究方法,将2021年8月—2023年8月在中南大学湘雅医院行LRH且符合标准的肝癌患者随机分为观察组和对照组,观察组术中采用LPDF,对照组则采用肝蒂优先法。收集并比较两组患者围术期临床指标。结果:共纳入19例患者,其中观察组10例,对照组9例。两组患者的基线资料差异无统计学意义(均P>0.05)。观察组的手术时间明显少于对照组(224.30 min vs.267.78 min,P=0.045),两组其余指标包括术中出血量和输血量、中转开腹率、术后排气时间、住院时间、术后第3天肝功能、并发症发生率,以及无复发生存率与总生存率差异均无统计学意义(均P>0.05)。结论:LPDF应用于LRH相较于传统的肝蒂优先法简化了肝蒂处理流程,缩短了手术时间,未增加术后并发症发生率,且一定程度上减少了出血风险,建议行进一步大样本量研究与推广。
基金supported by the National Key Plan for Research and Development of China(No.2022YFD1900602)the National Natural Science Foundation of China(Nos.42020104004,52022028,51779077,and 41501328)。
文摘Biological nitrogen(N)fixation(BNF)driven by diazotrophs is an important pathway for N input in agricultural ecosystems.However,free-living BNF and its associated diazotrophic communities under different fertilization practices in acidic soils are poorly studied.Here,we conducted a long-term(29 years)fertilization experiment to explore how fertilization affected free-living BNF via changing biotic and abiotic variables.The fertilization treatments included an unfertilized control(CK),chemical N,phosphorus(P),and potassium(K)fertilizers(NPK),NPK plus lime(NPKL),NPK plus straw(NPKS),NPK plus straw and lime(NPKSL),and NPK plus manure(NPKM).Compared with CK(1.51 nmol C_(2)H_(2)g^(-1)d^(-1)),BNF rate was significantly(P<0.05)higher in NPKM(1.99 nmol C_(2)H_(2)g^(-1)d^(-1))but lower in NPK(0.55 nmol C_(2)H_(2)g^(-1)d^(-1)),NPKL(0.61 nmol C_(2)H_(2)g^(-1)d^(-1)),and NPKS(0.69nmol C_(2)H_(2)g^(-1)d^(-1)).Similarly,chemical fertilization treatments without manure reduced the gene abundance(0.71×10^(8)-1.18×10^(8)copies g^(-1))andα-diversity(Shannon index,1.11-2.43)of diazotrophic communities,whereas the treatment with manure had a positive effect on diazotrophic abundance(3.23×10^(8)copies g^(-1))and Shannon index(3.36).Non-parametric multivariate analysis of variance(PERMANOVA)suggested that manure application(R^(2)=0.212,P=0.001)had a stronger influence on diazotrophic community composition than the addition of lime(R^(2)=0.115,P=0.019)or straw(R^(2)=0.064,P=0.161).Random forest modeling revealed that BNF rates can be significantly(P<0.05)explained by soil pH(9.9%),diazotrophic community attributes(composition,8.5%;Chao 1 index,8.1%;abundance,6.0%;Shannon index,5.7%),and soil total carbon(5.1%).Partial least squares path modeling(PLS-PM)suggested that the diazotrophic community attributes and soil properties mainly provided direct and indirect contributions to the variations in BNF rates,respectively.The dominant genera,Pelomonas,Azospirillum,and Dechloromonas,were positively associated with BNF rates,with their members being observed as keystone species in the community network.Application of chemical fertilizers combined with manure is an effective practice for improving BNF in acidic soils by affecting soil diazotrophic communities.
基金National Natural Science Foundation of China (51275446)Hebei Provincial Natural Science Foundation of China (E2016203492).
文摘Mechanical properties and creep behavior of Q460E continuous casting slab were studied by means of uniaxial tensile tests on a Gleeble-3800 thermomechanical simulator from 1000 to 1100 ℃.The high-temperature creep constitutional equation was derived based on experimental data.The parameters in the equation were calculated by using the regression analysis inverse-estimation method.The experimental curves in the primary and secondary creep stages are fitted well.A three-dimensional elastic-plastic and creep finite element model was proposed in order to investigate the bulging deformation of slab and the bulging deformation at the beginning position of bending segment on the slab continuous casting machine was computed accurately.The results indicate that the maximum bulging deformation appears at the geometric center of the slab.The maximum value of the bulging deformation obtained by the elastic-plastic analysis is 1.301 ram.Consideririg the creep effect,the deformation increases to 1.827 mm which is about 1.4 times the value obtained by the elastic-plastic analysis.The calculation of buleing deformation usin2 the elastic-plastic creed model is more reliable and/iccurate.
