口腔颌面部间隙感染(oral and maxillofacial space infections,OMSI)是颌面部潜在筋膜间隙的感染,是口腔颌面部的常见疾病。OMSI病例具有耐药菌感染增多、重症感染增多、致死风险增加等特点。为提高OMSI的治愈率,其治疗原则与方法需与...口腔颌面部间隙感染(oral and maxillofacial space infections,OMSI)是颌面部潜在筋膜间隙的感染,是口腔颌面部的常见疾病。OMSI病例具有耐药菌感染增多、重症感染增多、致死风险增加等特点。为提高OMSI的治愈率,其治疗原则与方法需与时俱进。因此,依据国内部分专家当前诊治OMSI的临床经验,结合国际同行治疗经验,本文从术前检查、检查结果解读、经验性用药原则、手术处理原则、术后换药原则、智齿冠周炎相关间隙感染的防治策略、血糖监测与控制、物理因子治疗原则、路德维希咽峡炎治疗和围手术期护理等10个方面进行系统性总结,形成共识,以期逐步实现我国口腔颌面外科同行诊治OMSI的规范化与标准化,最终达到提高我国OMSI的诊疗水平的目的。展开更多
Objectives:To develop a new Chinese medicine(CM)-based drug and to evaluate its safety and effect for suppressing acute respiratory distress syndrome(ARDS)in COVID-19 patients.Methods:A putative ARDS-suppressing drug ...Objectives:To develop a new Chinese medicine(CM)-based drug and to evaluate its safety and effect for suppressing acute respiratory distress syndrome(ARDS)in COVID-19 patients.Methods:A putative ARDS-suppressing drug Keguan-1 was first developed and then evaluated by a randomized,controlled two-arm trial.The two arms of the trial consist of a control therapy(alpha interferon inhalation,50(x g twice daily;and lopinavir/ritonavir,400 and 100 mg twice daily,respectively)and a testing therapy(control therapy plus Keguan-119.4 g twice daily)by random number table at 1:1 ratio with 24 cases each group.After 2-week treatment,adverse events,time to fever resolution,ARDS development,and lung injury on newly diagnosed COVID-19 patients were assessed.Results:An analysis of the data from the first 30 participants showed that the control arm and the testing arm did not exhibit any significant differences in terms of adverse events.Based on this result,the study was expanded to include a total of 48 participants(24 cases each arm).The results show that compared with the control arm,the testing arm exhibited a significant improvement in time to fever resolution(P=0.035),and a significant reduction in the development of ARDS(P=0.048).Conclusions:Keguan-1-based integrative therapy was safe and superior to the standard therapy in suppressing the development of ARDS in COVID-19 patients.(Trial registration No.NCT 04251871 at www.clinicaltrials.gov).展开更多
MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division proce...MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transfor- mants have more nuclei and higher anenpioid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants （Arabidopsis accession Col-0）, and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role forAtMYB59 in cell cycle regulation and plant root growth.展开更多
BACKGROUND Most cholangiocarcinoma patients with malignant obstructive jaundice(MOJ)have varying degrees of malnutrition and immunodeficiency preoperatively.Therefore,perioperative nutritional support has important cl...BACKGROUND Most cholangiocarcinoma patients with malignant obstructive jaundice(MOJ)have varying degrees of malnutrition and immunodeficiency preoperatively.Therefore,perioperative nutritional support has important clinical significance in the treatment of cholangiocarcinoma.AIM To investigate the effects of postoperative early enteral nutrition(EEN)on immunity function and clinical outcomes of cholangiocarcinoma patients with MOJ.METHODS This prospective clinical study included 60 cholangiocarcinoma patients with MOJ who underwent surgery.The patients were randomly divided into an experimental group and a control group according to the nutrition support modes.The control group received postoperative total parenteral nutrition(TPN),whereas the experimental group received postoperative EEN and parenteral nutrition(PN;EEN+PN).The clinical outcomes,postoperative immune function,incidences of surgical site infection and bile leakage,intestinal function recovery time,average hospitalization days,and hospitalization expenses of the two groups were assessed on postoperative days(PODs)1,3,and 7.RESULTS The CD3+T,CD4+T,CD8+T,and CD4+T/CD8+T cell count and the immunoglobulin(Ig)G,IgM,and IgA levels in the EEN+PN group were significantly higher than those in the TPN group on PODs 3 and 7(P<0.05),whereas no significant differences in the CD3+T,CD4+T,CD8+T,and CD4+T/CD8+T cell counts and IgG,IgM,and IgA levels before operation and on POD 1 were found between the two groups(P>0.05).The intestinal function recovery time and postoperative hospital stay were shorter(P<0.001 for both)in the EEN+PN group than in the TPN group.The hospitalization expenses of the EEN+PN group were lower than those of the TPN group(P<0.001).However,the incidence of abdominal distension was higher than in the EEN+PN group than in the TPN group(P<0.05).The incidence rates of biliary leakage and surgical site infection were not significantly different between the two groups(P>0.05).CONCLUSION A postoperative EEN program could reduce the incidence of post展开更多
流域土壤侵蚀预测对于了解未来土壤侵蚀发展趋势,制定未来水土保持治理策略具有重要意义。为了提出一种适用于黄土高原地区的易于评估未来不同土地利用管理策略的土壤侵蚀预测方法,该研究基于地形、降雨、土壤、遥感影像数据,完成韭园...流域土壤侵蚀预测对于了解未来土壤侵蚀发展趋势,制定未来水土保持治理策略具有重要意义。为了提出一种适用于黄土高原地区的易于评估未来不同土地利用管理策略的土壤侵蚀预测方法,该研究基于地形、降雨、土壤、遥感影像数据,完成韭园沟流域2010—2020年的土地利用空间分布解译,并计算历史时期(2010—2020)的土壤侵蚀模数,基于未来土地利用模拟(Future Land Use Simulation,FLUS)模型完成流域2025年土地利用分布状况预测,以此为基础获得未来植被覆盖措施因子和耕作措施因子,结合CSLE模型预测2025年自然发展、经济增长、生态保护3种不同土地利用变化情景下土壤侵蚀状况。结果表明:1)韭园沟流域土地利用类型主要为草地(面积占比62.23%)和林地(28.41%),其次是耕地、建筑物和水体,在2010—2020年期间土地利用空间分布格局经历了较大变化,林、草地面积增加8.36%,耕地面积减少30.3%。2)流域2010、2015、2020年这3a间土壤侵蚀模数平均值分别为19.49、15.83、20.7t/(hm^(2)·a),整体呈现先降低后增加的趋势,不同土地利用类型的土壤侵蚀模数由大到小为耕地(40.56t/(hm^(2)·a))、草地(18.79 t/(hm^(2)·a))、建设用地(10.25 t/(hm^(2)·a))、林地(8.02 t/(hm^(2)·a))。3)在积极的生态保护情景下,2025年林、草地面积较自然发展情景基本持平但林地面积比例有所增加,较经济增长情景林、草地面积增加5.06%,耕地面积较自然发展情景增加1.20%,较经济增长情景减少14.73%。4)2025年流域自然发展、经济增长、生态保护情景下土壤侵蚀模数分别为24.3、22.9、18.3 t/(hm^(2)·a)。采取积极的生态保护情景发展模式,建设用地面积适度扩张可以兼顾生态保护和经济发展的需要。该研究为流域未来的土地利用规划以及水土保持治理提供参考。展开更多
影响力最大化问题在社交网络中有着广泛的应用,一般地可以将社交网络抽象为静态图,影响力最大化问题是指在图中找出k个最有影响力的顶点,使得信息最大化传播.近年来对此问题的研究主要基于静态图,但是在现实中某些特定网络不可简单地被...影响力最大化问题在社交网络中有着广泛的应用,一般地可以将社交网络抽象为静态图,影响力最大化问题是指在图中找出k个最有影响力的顶点,使得信息最大化传播.近年来对此问题的研究主要基于静态图,但是在现实中某些特定网络不可简单地被抽象为静态图,如社交网络及路网中节点间只在某些特定时间存在联系,即节点间的联系是具有时序性的.因此,本文研究了时序图影响力最大化问题,即在时序图上寻找k个顶点使得信息在特定的时间段内最大化传播.传播模型的选择和节点间传播概率的计算是影响力最大化问题的基础,由于基于静态图的IC(Independent Cascade model)传播模型无法应用于时序图,因此本文首先对IC模型进行改进,并提出了ICT(Independent Cascade model on Temporal graph)传播模型,使信息可以通过ICT传播模型在时序图上进行传播.而后通过改进PageRank算法来进行计算节点间的传播概率.然后在此基础上将时序图影响力最大化问题分为两步来进行实现.第一步首先研究时序图节点影响力的计算,并提出了用来计算节点影响力的SIC(Single Node Influence Computation)算法,然后通过对时序图中节点联系时序性这一特性的研究提出了一种改进算法ISIC(Improved SIC).第二步是在第一步结果的基础上来寻找k个种子节点,首先提出了一种基本的时序图影响力最大化算法BIMT(Basic Method for IMTG).但BIMT难以高效解决大规模时序图影响力最大化问题,因此通过优化节点边际效应的计算时间,提出了高效的AIMT(Advanced Method for IMTG)算法,然后通过避免某些节点边际效应的重复计算,对AIMT算法进行改进,从而提出了IMIT(Improved Method for IMTG)算法.最后通过大量实验验证了AIMT和IMIT两种算法高效性和扩展性,相比于BIMT算法,AIMT和IMIT可以更加快速地解决大规模时序图影响力最大化问题.展开更多
To investigate the stability of rock mass in high geostress underground powerhouse caverns subjected to excavation,a microseismic(MS)monitoring system was established and the discrete element method(DEM)-based numeric...To investigate the stability of rock mass in high geostress underground powerhouse caverns subjected to excavation,a microseismic(MS)monitoring system was established and the discrete element method(DEM)-based numerical simulation was carried out.The tempo-spatial damage characteristics of rock mass were analyzed.The evolution laws of MS source parameters during the formation of a rock collapse controlled by high geostress and geological structure were investigated.Additionally,a three-dimensional DEM model of the underground powerhouse caverns was built to reveal the deformation characteristics of rock mass.The results indicated that the MS events induced by excavation of high geostress underground powerhouse caverns occurred frequently.The large-stake crown of the main powerhouse was the main damage area.Prior to the rock collapse,the MS event count and accumulated energy release increased rapidly,while the apparent stress sharply increased and then decreased.The amount and proportion of shear and mixed MS events remarkably increased.The maximum displacement was generally located near the spandrel areas.The MS monitoring data and numerical simulation were in good agreement,which can provide significant references for damage evaluation and disaster forecasting in high geostress underground powerhouse caverns.展开更多
AIM： To detect the expression of fragile histidine triad （FHIT） in normal colorectal tissue, colorectal adenoma and colorectal cancer （CRC） tissue, and to analyze its relationship with the clinicopathological fea...AIM： To detect the expression of fragile histidine triad （FHIT） in normal colorectal tissue, colorectal adenoma and colorectal cancer （CRC） tissue, and to analyze its relationship with the clinicopathological features of CRC, and apoptosis-associatecl proteins （Bcl-2, Bax, survivin） and apoptosis in colorectal cancer. METHODS： FHIT mRNA analysis was performed by nested reverse transcription-polymerase chain reaction （RT-PCR） assay. Tissue microarray （TMA） was established to detect the expression of FHIT, Bcl-2, Bax and survivin genes in 80 CRC tissue specimens, 16 colorectal adenoma tissue specimens and 16 hemorrhoid （PPH） tissue specimens during the same period of time as the control. Citrate-microwave-SP was used as immunohistochemical method. The relationship between clinicopathological factors, such as differentiation grades and 5-year survival rate was observed. TUNEL assay was used to detect the apoptosis index in 80 CRC tissue specimens. RESULTS： Ten out of 26 （38.5%） CRC tissue specimens expressed aberrant FHIT transcripts, none of the aberrant FHIT transcripts was observed in the matchednormal tissue and colorectal adenoma tissue by nested RT-PCR assay. The positive rate of FHIT gene expression in normal colorectal tissue, colorectal adenoma and carcinoma tissue was 93.75%, 68.75% and 46.25%, respectively. Clinicopathological analysis of patients showed that the decreased FHIT gene expression was not associated with age, sex, serum CEA levels, tumor site and size, histological classification. However, the expression of FHIT was correlated with differentiation grades, pathological stages, lymph node metastases and 5-year survival rate after operation. The positive rate of apoptosis-associated proteins （Bax, Bcl-2 and survivin） in CRC tissue was 72.50%, 51.25% and 77.50%, respectively. The expression of these apoptosisassociated proteins in CRC tissue was correlated with the expression of FHIT. The mean apoptosis index in FHIT negative tumors was significantly lower th展开更多
Some studies have indicated that the Wnt/β-catenin signaling pathway is activated following spinal cord injury, and expression levels of specific proteins, including low-density lipoprotein receptor related protein-6...Some studies have indicated that the Wnt/β-catenin signaling pathway is activated following spinal cord injury, and expression levels of specific proteins, including low-density lipoprotein receptor related protein-6 phosphorylation, β-catenin, and glycogen synthase kinase-3β, are significantly altered. We hypothesized that methylprednisolone treatment contributes to functional recovery after spinal cord injury by inhibiting apoptosis and activating the Wnt/β-catenin signaling pathway. In the current study, 30 mg/kg methylprednisolone was injected into rats with spinal cord injury immediately post-injury and at 1 and 2 days post-injury. Basso, Beattie, and Bresnahan scores showed that methylprednisolone treatment significantly promoted locomotor functional recovery between 2 and 6 weeks post-injury. The number of surviving motor neurons increased, whereas the lesion size significantly decreased following methylprednisolone treatment at 7 days post-injury. Additionally, caspase-3, caspase-9, and Bax protein expression levels and the number of apoptotic cells were reduced at 3 and 7 days post-injury, while Bcl-2 levels at 7 days post-injury were higher in methylprednisolone-treated rats compared with saline-treated rats. At 3 and 7 days post-injury, methylprednisolone up-regulated expression and activation of the Wnt/β-catenin signaling pathway, including low-density lipoprotein receptor related protein-6 phosphorylation, β-catenin, and glycogen synthase kinase-3β phosphorylation. These results indicate that methylprednisolone-induced neuroprotection may correlate with activation of the Wnt/β-catenin signaling pathway.展开更多
Rock mass large deformation in underground powerhouse caverns has been a severe hazard in hydropower engineering in Southwest China.During the development of rock mass large deformation,a sequence of fractures was gen...Rock mass large deformation in underground powerhouse caverns has been a severe hazard in hydropower engineering in Southwest China.During the development of rock mass large deformation,a sequence of fractures was generated that can be monitored using microseismic(MS)monitoring techniques.Two MS monitoring systems were established in two typical underground powerhouse caverns featuring distinct geostress levels.The MS b-values associated with rock mass large deformation and their temporal variation are analysed.The results showed that the MS bvalue in course of rock mass deformation was less than 1.0 in the underground powerhouse caverns at a high stress level while larger than 1.5 at a low stress level.Prior to the rock mass deformation,the MS b-values derived from both the high-stress and low-stress underground powerhouse caverns show an incremental decrease over 10%within 10 d.The results contribute to understanding the fracturing characteristics of MS sources associated with rock mass large deformation and provide a reference for early warning of rock mass large deformation in underground powerhouse caverns.展开更多
文摘口腔颌面部间隙感染(oral and maxillofacial space infections,OMSI)是颌面部潜在筋膜间隙的感染,是口腔颌面部的常见疾病。OMSI病例具有耐药菌感染增多、重症感染增多、致死风险增加等特点。为提高OMSI的治愈率,其治疗原则与方法需与时俱进。因此,依据国内部分专家当前诊治OMSI的临床经验,结合国际同行治疗经验,本文从术前检查、检查结果解读、经验性用药原则、手术处理原则、术后换药原则、智齿冠周炎相关间隙感染的防治策略、血糖监测与控制、物理因子治疗原则、路德维希咽峡炎治疗和围手术期护理等10个方面进行系统性总结,形成共识,以期逐步实现我国口腔颌面外科同行诊治OMSI的规范化与标准化,最终达到提高我国OMSI的诊疗水平的目的。
基金the National Administration of Traditional Chinese Medicine Project(No.2020ZYLCYJ05-1)the National Natural Science Foundation of China(Nos.81630100,81721002,81930110)+2 种基金China PLA Biosecurity Project(No.19SWAQ13)China PLA Emergency Project(BWS20J006)the Beijing Administration of Traditional Chinese Medicine Project(Nos.YJ2020-03,SYFY202011)。
文摘Objectives:To develop a new Chinese medicine(CM)-based drug and to evaluate its safety and effect for suppressing acute respiratory distress syndrome(ARDS)in COVID-19 patients.Methods:A putative ARDS-suppressing drug Keguan-1 was first developed and then evaluated by a randomized,controlled two-arm trial.The two arms of the trial consist of a control therapy(alpha interferon inhalation,50(x g twice daily;and lopinavir/ritonavir,400 and 100 mg twice daily,respectively)and a testing therapy(control therapy plus Keguan-119.4 g twice daily)by random number table at 1:1 ratio with 24 cases each group.After 2-week treatment,adverse events,time to fever resolution,ARDS development,and lung injury on newly diagnosed COVID-19 patients were assessed.Results:An analysis of the data from the first 30 participants showed that the control arm and the testing arm did not exhibit any significant differences in terms of adverse events.Based on this result,the study was expanded to include a total of 48 participants(24 cases each arm).The results show that compared with the control arm,the testing arm exhibited a significant improvement in time to fever resolution(P=0.035),and a significant reduction in the development of ARDS(P=0.048).Conclusions:Keguan-1-based integrative therapy was safe and superior to the standard therapy in suppressing the development of ARDS in COVID-19 patients.(Trial registration No.NCT 04251871 at www.clinicaltrials.gov).
文摘MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transfor- mants have more nuclei and higher anenpioid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants （Arabidopsis accession Col-0）, and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role forAtMYB59 in cell cycle regulation and plant root growth.
基金National Natural Science Foundation of China,No.81660398The Hospital Key Program of National Scientific Research Cultivation Plan,No.19SYPYA-12.
文摘BACKGROUND Most cholangiocarcinoma patients with malignant obstructive jaundice(MOJ)have varying degrees of malnutrition and immunodeficiency preoperatively.Therefore,perioperative nutritional support has important clinical significance in the treatment of cholangiocarcinoma.AIM To investigate the effects of postoperative early enteral nutrition(EEN)on immunity function and clinical outcomes of cholangiocarcinoma patients with MOJ.METHODS This prospective clinical study included 60 cholangiocarcinoma patients with MOJ who underwent surgery.The patients were randomly divided into an experimental group and a control group according to the nutrition support modes.The control group received postoperative total parenteral nutrition(TPN),whereas the experimental group received postoperative EEN and parenteral nutrition(PN;EEN+PN).The clinical outcomes,postoperative immune function,incidences of surgical site infection and bile leakage,intestinal function recovery time,average hospitalization days,and hospitalization expenses of the two groups were assessed on postoperative days(PODs)1,3,and 7.RESULTS The CD3+T,CD4+T,CD8+T,and CD4+T/CD8+T cell count and the immunoglobulin(Ig)G,IgM,and IgA levels in the EEN+PN group were significantly higher than those in the TPN group on PODs 3 and 7(P<0.05),whereas no significant differences in the CD3+T,CD4+T,CD8+T,and CD4+T/CD8+T cell counts and IgG,IgM,and IgA levels before operation and on POD 1 were found between the two groups(P>0.05).The intestinal function recovery time and postoperative hospital stay were shorter(P<0.001 for both)in the EEN+PN group than in the TPN group.The hospitalization expenses of the EEN+PN group were lower than those of the TPN group(P<0.001).However,the incidence of abdominal distension was higher than in the EEN+PN group than in the TPN group(P<0.05).The incidence rates of biliary leakage and surgical site infection were not significantly different between the two groups(P>0.05).CONCLUSION A postoperative EEN program could reduce the incidence of post
文摘流域土壤侵蚀预测对于了解未来土壤侵蚀发展趋势,制定未来水土保持治理策略具有重要意义。为了提出一种适用于黄土高原地区的易于评估未来不同土地利用管理策略的土壤侵蚀预测方法,该研究基于地形、降雨、土壤、遥感影像数据,完成韭园沟流域2010—2020年的土地利用空间分布解译,并计算历史时期(2010—2020)的土壤侵蚀模数,基于未来土地利用模拟(Future Land Use Simulation,FLUS)模型完成流域2025年土地利用分布状况预测,以此为基础获得未来植被覆盖措施因子和耕作措施因子,结合CSLE模型预测2025年自然发展、经济增长、生态保护3种不同土地利用变化情景下土壤侵蚀状况。结果表明:1)韭园沟流域土地利用类型主要为草地(面积占比62.23%)和林地(28.41%),其次是耕地、建筑物和水体,在2010—2020年期间土地利用空间分布格局经历了较大变化,林、草地面积增加8.36%,耕地面积减少30.3%。2)流域2010、2015、2020年这3a间土壤侵蚀模数平均值分别为19.49、15.83、20.7t/(hm^(2)·a),整体呈现先降低后增加的趋势,不同土地利用类型的土壤侵蚀模数由大到小为耕地(40.56t/(hm^(2)·a))、草地(18.79 t/(hm^(2)·a))、建设用地(10.25 t/(hm^(2)·a))、林地(8.02 t/(hm^(2)·a))。3)在积极的生态保护情景下,2025年林、草地面积较自然发展情景基本持平但林地面积比例有所增加,较经济增长情景林、草地面积增加5.06%,耕地面积较自然发展情景增加1.20%,较经济增长情景减少14.73%。4)2025年流域自然发展、经济增长、生态保护情景下土壤侵蚀模数分别为24.3、22.9、18.3 t/(hm^(2)·a)。采取积极的生态保护情景发展模式,建设用地面积适度扩张可以兼顾生态保护和经济发展的需要。该研究为流域未来的土地利用规划以及水土保持治理提供参考。
文摘影响力最大化问题在社交网络中有着广泛的应用,一般地可以将社交网络抽象为静态图,影响力最大化问题是指在图中找出k个最有影响力的顶点,使得信息最大化传播.近年来对此问题的研究主要基于静态图,但是在现实中某些特定网络不可简单地被抽象为静态图,如社交网络及路网中节点间只在某些特定时间存在联系,即节点间的联系是具有时序性的.因此,本文研究了时序图影响力最大化问题,即在时序图上寻找k个顶点使得信息在特定的时间段内最大化传播.传播模型的选择和节点间传播概率的计算是影响力最大化问题的基础,由于基于静态图的IC(Independent Cascade model)传播模型无法应用于时序图,因此本文首先对IC模型进行改进,并提出了ICT(Independent Cascade model on Temporal graph)传播模型,使信息可以通过ICT传播模型在时序图上进行传播.而后通过改进PageRank算法来进行计算节点间的传播概率.然后在此基础上将时序图影响力最大化问题分为两步来进行实现.第一步首先研究时序图节点影响力的计算,并提出了用来计算节点影响力的SIC(Single Node Influence Computation)算法,然后通过对时序图中节点联系时序性这一特性的研究提出了一种改进算法ISIC(Improved SIC).第二步是在第一步结果的基础上来寻找k个种子节点,首先提出了一种基本的时序图影响力最大化算法BIMT(Basic Method for IMTG).但BIMT难以高效解决大规模时序图影响力最大化问题,因此通过优化节点边际效应的计算时间,提出了高效的AIMT(Advanced Method for IMTG)算法,然后通过避免某些节点边际效应的重复计算,对AIMT算法进行改进,从而提出了IMIT(Improved Method for IMTG)算法.最后通过大量实验验证了AIMT和IMIT两种算法高效性和扩展性,相比于BIMT算法,AIMT和IMIT可以更加快速地解决大规模时序图影响力最大化问题.
文摘收集陕西省结核病防治院2021年10月至2022年7月疑似肺结核住院患者的肺泡灌洗液,同时进行涂片抗酸杆菌染色、分枝杆菌BACTEC MGIT 960液体培养(简称“培养”)及菌种鉴定、GeneXpert MTB/RIF、结核分枝杆菌RNA恒温扩增实时荧光检测技术(simultaneous amplification and testing for Mycobacterium tuberculosis,SAT-TB),并对结果进行分析。以培养法(菌种鉴定结果为结核分枝杆菌复合群)为参考标准,SAT-TB诊断肺结核的敏感度为80.61%(399/495),特异度为87.74%(1259/1435),阳性预测值为69.39%(399/575),阴性预测值为92.92%(1259/1355),约登指数为0.68。SAT-TB技术具有敏感度和特异度较高的特点,对临床快速诊断活动性结核病具有一定的价值。
基金Project(2017YFC1501100)supported by the National Key R&D Program of ChinaProjects(51809221,51679158)supported by the National Natural Science Foundation of China。
文摘To investigate the stability of rock mass in high geostress underground powerhouse caverns subjected to excavation,a microseismic(MS)monitoring system was established and the discrete element method(DEM)-based numerical simulation was carried out.The tempo-spatial damage characteristics of rock mass were analyzed.The evolution laws of MS source parameters during the formation of a rock collapse controlled by high geostress and geological structure were investigated.Additionally,a three-dimensional DEM model of the underground powerhouse caverns was built to reveal the deformation characteristics of rock mass.The results indicated that the MS events induced by excavation of high geostress underground powerhouse caverns occurred frequently.The large-stake crown of the main powerhouse was the main damage area.Prior to the rock collapse,the MS event count and accumulated energy release increased rapidly,while the apparent stress sharply increased and then decreased.The amount and proportion of shear and mixed MS events remarkably increased.The maximum displacement was generally located near the spandrel areas.The MS monitoring data and numerical simulation were in good agreement,which can provide significant references for damage evaluation and disaster forecasting in high geostress underground powerhouse caverns.
基金Supported by the Natural Science Foundation of Guangdong Province, No. 06020005
文摘AIM： To detect the expression of fragile histidine triad （FHIT） in normal colorectal tissue, colorectal adenoma and colorectal cancer （CRC） tissue, and to analyze its relationship with the clinicopathological features of CRC, and apoptosis-associatecl proteins （Bcl-2, Bax, survivin） and apoptosis in colorectal cancer. METHODS： FHIT mRNA analysis was performed by nested reverse transcription-polymerase chain reaction （RT-PCR） assay. Tissue microarray （TMA） was established to detect the expression of FHIT, Bcl-2, Bax and survivin genes in 80 CRC tissue specimens, 16 colorectal adenoma tissue specimens and 16 hemorrhoid （PPH） tissue specimens during the same period of time as the control. Citrate-microwave-SP was used as immunohistochemical method. The relationship between clinicopathological factors, such as differentiation grades and 5-year survival rate was observed. TUNEL assay was used to detect the apoptosis index in 80 CRC tissue specimens. RESULTS： Ten out of 26 （38.5%） CRC tissue specimens expressed aberrant FHIT transcripts, none of the aberrant FHIT transcripts was observed in the matchednormal tissue and colorectal adenoma tissue by nested RT-PCR assay. The positive rate of FHIT gene expression in normal colorectal tissue, colorectal adenoma and carcinoma tissue was 93.75%, 68.75% and 46.25%, respectively. Clinicopathological analysis of patients showed that the decreased FHIT gene expression was not associated with age, sex, serum CEA levels, tumor site and size, histological classification. However, the expression of FHIT was correlated with differentiation grades, pathological stages, lymph node metastases and 5-year survival rate after operation. The positive rate of apoptosis-associated proteins （Bax, Bcl-2 and survivin） in CRC tissue was 72.50%, 51.25% and 77.50%, respectively. The expression of these apoptosisassociated proteins in CRC tissue was correlated with the expression of FHIT. The mean apoptosis index in FHIT negative tumors was significantly lower th
基金supported by the National Natural Science Foundation of China,No.81471854
文摘Some studies have indicated that the Wnt/β-catenin signaling pathway is activated following spinal cord injury, and expression levels of specific proteins, including low-density lipoprotein receptor related protein-6 phosphorylation, β-catenin, and glycogen synthase kinase-3β, are significantly altered. We hypothesized that methylprednisolone treatment contributes to functional recovery after spinal cord injury by inhibiting apoptosis and activating the Wnt/β-catenin signaling pathway. In the current study, 30 mg/kg methylprednisolone was injected into rats with spinal cord injury immediately post-injury and at 1 and 2 days post-injury. Basso, Beattie, and Bresnahan scores showed that methylprednisolone treatment significantly promoted locomotor functional recovery between 2 and 6 weeks post-injury. The number of surviving motor neurons increased, whereas the lesion size significantly decreased following methylprednisolone treatment at 7 days post-injury. Additionally, caspase-3, caspase-9, and Bax protein expression levels and the number of apoptotic cells were reduced at 3 and 7 days post-injury, while Bcl-2 levels at 7 days post-injury were higher in methylprednisolone-treated rats compared with saline-treated rats. At 3 and 7 days post-injury, methylprednisolone up-regulated expression and activation of the Wnt/β-catenin signaling pathway, including low-density lipoprotein receptor related protein-6 phosphorylation, β-catenin, and glycogen synthase kinase-3β phosphorylation. These results indicate that methylprednisolone-induced neuroprotection may correlate with activation of the Wnt/β-catenin signaling pathway.
基金Projects(51809221,51679158)supported by the National Natural Science Foundation of ChinaProject(KFJJ20-06M)supported by the State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology),China。
文摘Rock mass large deformation in underground powerhouse caverns has been a severe hazard in hydropower engineering in Southwest China.During the development of rock mass large deformation,a sequence of fractures was generated that can be monitored using microseismic(MS)monitoring techniques.Two MS monitoring systems were established in two typical underground powerhouse caverns featuring distinct geostress levels.The MS b-values associated with rock mass large deformation and their temporal variation are analysed.The results showed that the MS bvalue in course of rock mass deformation was less than 1.0 in the underground powerhouse caverns at a high stress level while larger than 1.5 at a low stress level.Prior to the rock mass deformation,the MS b-values derived from both the high-stress and low-stress underground powerhouse caverns show an incremental decrease over 10%within 10 d.The results contribute to understanding the fracturing characteristics of MS sources associated with rock mass large deformation and provide a reference for early warning of rock mass large deformation in underground powerhouse caverns.
