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Investigation on the physical–mechanical response characteristics and failure mechanisms of shale under the laser thermal field
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作者 Yuze Du Jing Xie +7 位作者 Zheqiang Jia Li Ren Zeyu Zhu junjun liu Lei Yang Ting Ai Bengao Yang Mingzhong Gao 《International Journal of Coal Science & Technology》 2025年第2期158-181,共24页
The mainstream method for extracting shale gas involves hydraulic fracturing to create fracture networks.However,as extraction depth increases,notable issues such as rapid production decline,low recovery rates,high wa... The mainstream method for extracting shale gas involves hydraulic fracturing to create fracture networks.However,as extraction depth increases,notable issues such as rapid production decline,low recovery rates,high water consumption,and resource waste become apparent.Identifying new and efficient auxiliary rock-breaking technologies is crucial for overcoming these challenges.The laser,successfully utilized in industrial production,medical treatment,and technological research,offers unique features such as good directionality,coherence,and high energy density,providing novel possibilities for addressing the limitations of existing deep reservoir transformation.This research focuses on a novel laser-assisted rock-breaking technology,with shale featuring different bedding angles as the subject of investigation.The investigation methodically explored how shale responded to thermal fracture at high temperatures when exposed to laser irradiation with different spot diameter.It investigates the spatiotemporal evolution characteristics of the shale temperature field under laser irradiation,the propagation features of cracks on shale surface,and the physicochemical fracture mechanisms.The research yields the following results:(1)The region of thermal influence of the irradiation surface can be divided into three regions based on the change of rise curve of temperature in the shale surface.(2)Based on the scanning electron microscopy(SEM)testing,combined with the macroscopic and microscopic morphological characteristics of shale fracture surfaces,it reveals significantly distinct zoning characteristics in the roughness of the rock sample’s fracture surfaces after laser irradiation.(3)The thermal fracturing process of shale under laser irradiation involves chemical reactions of constituent minerals and stress generated by the thermal expansion of shale oil in the reservoir.(4)The damage and fracture of shale under the irradiation of laser show significant bedding effect,and there are three modes of rock sample failure:Pattern T(thermal failure),Pattern T-B(thermal and bedding synergistic failure),and Pattern B(bedding failure).The research findings presented in this article serve as a foundation and reference for the theory and technology of laser-assisted shale gas extraction. 展开更多
关键词 SHALE LASER Bedding effect Crack propagation Fracture mechanism
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DFT calculations and dynamic NMR revealed the coalescent NMR phenomena of the 6/6/6/9 tetracyclic merosesquiterpenoids with an unprecedented 9,15-dioxatetracyclo[8.5.3.0^(4,17).0^(14,18)]octadecane core skeleton
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作者 Hanqi Zhang Biao Gao +6 位作者 Yuanyuan Feng Guijuan Zheng Zhijun liu Lichun Kong junjun liu Haji Akber Aisa Guangmin Yao 《Chinese Chemical Letters》 2025年第9期507-511,共5页
Two pairs of novel 6/6/6/9 tetracyclic merosesquiterpenoid enantiomers,dauroxonanols A(1)and B(2),possessing an unprecedented 9,15-dioxatetracyclo[8.5.3.0^(4.17).0^(14.18)]octadecane core skeleton,were isolated from R... Two pairs of novel 6/6/6/9 tetracyclic merosesquiterpenoid enantiomers,dauroxonanols A(1)and B(2),possessing an unprecedented 9,15-dioxatetracyclo[8.5.3.0^(4.17).0^(14.18)]octadecane core skeleton,were isolated from Rhododendron dauricum.The nuclear magnetic resonance(NMR)spectra of 1 and 2 showed very broad resonances,and^(13)C NMR spectrum of 1 exhibited only 13 instead of 22 carbon resonances.These broadening or missing NMR resonances led to a great challenge to elucidate their structures using NMR data analysis.Their structures and absolute configurations of 1 and 2 were finally determined by single crystal X-ray diffraction analysis,chiral separation,and electronic circular dichroism(ECD)calculations.Plausible biosynthetic pathways for 1 and 2 are proposed.Conformational analysis,density functional theory(DFT)calculations,and dynamic NMR assigned the coalescent NMR phenomena of 1 and 2 to the conformational changes of the flexible oxonane ring.Dauroxonanols A(1)and B(2)showed potentα-glucosidase inhibitory activities,2-8 times potent than acarbose,an antidiabetic drug targetingα-glucosidase in clinic. 展开更多
关键词 Merosesquiterpenoid enantiomers Rhododendron dauricum Nine-membered ring DFT calculations Dynamic NMR study
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A novel and visible ratiometric fluorescence determination of carbaryl based on red emissive carbon dots by a solvent-free method
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作者 Meiling Xu Xinyang Li +6 位作者 Pengyuan liu junjun liu Xiao Han Guodong Chai Shuangling Zhong Bai Yang Liying Cui 《Chinese Chemical Letters》 2025年第2期286-290,共5页
In this study,a simple and effective ratiometric fluorescence method has been developed for carbaryl detection,utilizing red emissive carbon dots(R-CDs).The underlying principle of this proposed strategy relies on the... In this study,a simple and effective ratiometric fluorescence method has been developed for carbaryl detection,utilizing red emissive carbon dots(R-CDs).The underlying principle of this proposed strategy relies on the rapid hydrolysis of carbaryl under an alkaline condition and production of 1-naphthol with blue-emission at 462 nm.Furthermore,the as-synthesized R-CDs(Em.677 nm),serve as a reference,enhancing the visual tracking of carbaryl through the transformation of fluorescent color from red to blue.The concentration of carbaryl exhibits a commendable linear correlation with the ratio of fluorescence intensity,ranging from 0 to 20μg/m L(R^(2)=0.9989)with a low detection limit of 0.52 ng/m L.Additionally,the described methodology can be used for the enzyme-free visual assay of carbaryl,even in the presence of other carbamate pesticides and metal ions,in tap water and lake water samples with excellent accuracy(spiked recoveries,94%-106.1%),high precision(relative standard deviation(RSD)≤2.42),and remarkable selectivity.This fast and highly sensitive naked-eye ratiometric sensor holds immense promise for carbaryl detection in intricate environments and food safety fields. 展开更多
关键词 Carbon dots Visual detection Fluorescence sensor Quantum yield Carbaryl detection
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Hemodynamic disturbance and mTORC1 activation:Unveiling the biomechanical pathogenesis of thoracic aortic aneurysms in Marfan syndrome
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作者 Ming-Yuan liu Meili Wang +5 位作者 junjun liu An-Qiang Sun Chang-Shun He Xin Cong Wei Kong Wei Li 《Journal of Pharmaceutical Analysis》 2025年第2期459-473,共15页
Thoracic aortic aneurysm(TAA)significantly endangers the lives of individuals with Marfan syndrome(MFS),yet the intricacies of their biomechanical origins remain elusive.Our investigation delves into the pivotal role ... Thoracic aortic aneurysm(TAA)significantly endangers the lives of individuals with Marfan syndrome(MFS),yet the intricacies of their biomechanical origins remain elusive.Our investigation delves into the pivotal role of hemodynamic disturbance in the pathogenesis of TAA,with a particular emphasis on the mechanistic contributions of the mammalian target of rapamycin(mTOR)signaling cascade.We uncovered that activation of the mTOR complex 1(mTORC1)within smooth muscle cells,instigated by the oscillatory wall shear stress(OSS)that stems from disturbed flow(DF),is a catalyst for TAA progression.This revelation was corroborated through both an MFS mouse model(Fbn1+/C1039G)and clinical MFS specimens.Crucially,our research demonstrates a direct linkage between the activation of the mTORC1 pathway and the intensity in OSS.Therapeutic administration of rapamycin suppresses mTORC1 activity,leading to the attenuation of aberrant SMC behavior,reduced inflammatory infiltration,and restoration of extracellular matrix integrity—collectively decelerating TAA advancement in our mouse model.These insights posit the mTORC1 axis as a strategic target for intervention,offering a novel approach to manage TAAs in MFS and potentially pave insights for current treatment paradigms. 展开更多
关键词 Thoracic aortic aneurysm(TAA) mTORC1 Marfan syndrome Biomechanicalpathogenesis Wall shear stress(WSS)
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Development of a reporter HBoV1 strain for antiviral drug screening and life cycle studies
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作者 Jielin Tang Sijie Chen +11 位作者 Yi Zhong Yijun Deng Dan Huang junjun liu Yi Zheng Jiyuan Xu Bao Xue Fan Wang Yuan Zhou Hanzhong Wang Qi Yang Xinwen Chen 《Virologica Sinica》 2025年第2期275-283,共9页
Human bocavirus 1(HBoV1;family:Parvoviridae)causes a wide spectrum of respiratory diseases in children and gastroenteritis in adults.A lack of sensitive cell lines and efficient animal models hinders research on HBoV,... Human bocavirus 1(HBoV1;family:Parvoviridae)causes a wide spectrum of respiratory diseases in children and gastroenteritis in adults.A lack of sensitive cell lines and efficient animal models hinders research on HBoV,including the development of anti-HBoV drugs or vaccines.Although the construction of a wild-type HBoV1 infectious clone has been reported,generating HBoV1 infectious clone carrying foreign reporter genes with suitable insertion sites in its genome while retaining replicative ability remains challenging.Here,HBoV1 infectious clones harboring the 11-amino-acid HiBiT tag at five distinct insertion sites were constructed and evaluated.Only the recombinant HBoV1 carrying the HiBiT tag in the N-terminus of the NS1 protein(HBoV1-HiBiTNS1)displayed comparable characteristics to wild-type HBoV1 as determined via the analysis of viral DNA copy number,NanoLuc activity,viral protein expression,and the formation of replication intermediates.Notably,the replication kinetics of HBoV1-HiBiTNS1 could be examined by monitoring NanoLuc activity,which was noted to be correlated with the viral DNA level.Additionally,we successfully applied HiBiT-tagged HBoV1 for the evaluation of antiviral drug activity and identified ivermectin(EC50=2.27μM)as a potent anti-HBoV1 replication drug.Overall,our study demonstrated that the HBoV1-HiBiTNS1 reporter can serve as a convenient platform for screening candidate drugs targeting HBoV1 replication and may also be useful for investigating the life cycle of the virus. 展开更多
关键词 Human bocavirus(HBoV) HiBiT tag Infectious clone Antiviral drug evaluation
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Evidence-Based Practice of Nutrition Management in Chronic Heart Failure Patients Based on Knowledge-to-Action Transformation Model
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作者 Jing Zhang junjun liu 《Open Journal of Applied Sciences》 2025年第2期400-410,共11页
Objective: To develop a best-evidence-based optimal nutrition management plan for patients with chronic heart failure, apply it in clinical practice, and evaluate its effectiveness. Methods: Use the KTA knowledge tran... Objective: To develop a best-evidence-based optimal nutrition management plan for patients with chronic heart failure, apply it in clinical practice, and evaluate its effectiveness. Methods: Use the KTA knowledge translation model to guide evidence-based practice in nutrition management, and compare the nutritional status, cardiac function status, quality of life, and quality review indicators of chronic heart failure patients before and after the application of evidence. Results: After the application of evidence, the nutritional status indicators (MNA-SF score, albumin, hemoglobin) of two groups of heart failure patients significantly increased compared to before the application of evidence, with statistically significant differences (p Conclusion: The KTA knowledge translation model provides methodological guidance for the implementation of evidence-based practice for heart failure patients. This evidence-based practice project is beneficial for improving the outcomes of malnutrition in chronic heart failure patients and is conducive to standardizing nursing pathways, thereby promoting the improvement of nursing quality. 展开更多
关键词 Chronic Heart Failure Knowledge Transformation Mode Nutrition Management Evidence-Based Practice
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Talaroclauxins A and B:Duclauxin-ergosterol and duclauxin-polyketide hybrid metabolites with complicated skeletons from Talaromyces stipitatus
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作者 Qin Li Mi Zhang +11 位作者 Xiaotian Zhang Lanqin Li Meijia Zheng Jinbing Kang Fei liu Qun Zhou Xiaonian Li Weiguang Sun junjun liu Chunmei Chen Hucheng Zhu Yonghui Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第1期300-304,共5页
Talaroclauxins A and B(1 and 2),two novel duclauxin hybrids,were obtained from Talaromyces stipitatus,along with three new(3-5)and one known analogue(6).Their structures were determined by NMR spectroscopy,HRESIMS,sin... Talaroclauxins A and B(1 and 2),two novel duclauxin hybrids,were obtained from Talaromyces stipitatus,along with three new(3-5)and one known analogue(6).Their structures were determined by NMR spectroscopy,HRESIMS,single-crystal X-ray diffraction,and quantum chemical calculations.Compound 1 is the first example of duclauxin-ergosterol hybrid featuring an unprecedented dodecacyclic ring system formed via a[4+2]cycloaddition,while compound 2,bearing an unusual 6/6/6/5/6/6/6/6 ring system,is a new member of the rare duclauxin-polyketide hybrid class of natural products.Plausible biosynthetic pathways for 1-6 are proposed.Compound 5 displayed moderate neuroprotective effects in glutamate sodium-induced SH-SY5Y cells. 展开更多
关键词 Talaromyces stipitatus(Trichocomaceae) Duclauxin hybrids Single-crystal X-ray diffraction Biosynthetic pathways Neuroprotective effects
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AbnI:Anα-ketoglutarate-dependent dioxygenase involved in brassicicene C-H functionalization and ring system rearrangement
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作者 Wenling Yuan Fengli Li +8 位作者 Zhe Chen Qiaoxin Xu Zhenhua Guan Nanyu Yao Zhengxi Hu junjun liu Yuan Zhou Ying Ye Yonghui Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第5期213-217,共5页
We reported the characterization of a novel brassicicene diterpene biosynthetic gene cluster,which contains a uniqueα-ketoglutarate-dependent dioxygenase(αKGD)enzyme,AbnI.Our findings revealed that AbnI demonstrates... We reported the characterization of a novel brassicicene diterpene biosynthetic gene cluster,which contains a uniqueα-ketoglutarate-dependent dioxygenase(αKGD)enzyme,AbnI.Our findings revealed that AbnI demonstrates remarkable substrate promiscuity and is capable of activating multiple sites on both 5-8-5 and 5-9-5 brassicicene skeletons,resulting in skeleton modifications and an unexpected ring system rearrangement.These results suggested the potential utility of AbnI as an enzymatic tool for terpene C-H functionalization.In addition,the catalytic mechanism of AbnI and its potential ecological implications were discussed. 展开更多
关键词 Fungal diterpenes α-Ketoglutarate-dependent dioxygenase C-H functionalization REARRANGEMENT Brassicicenes
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Summary of the Best Evidence for Puncture Management During the Early Stage of Autologous Arteriovenous Fistula in Maintenance Hemodialysis Patients
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作者 Xiaoxiao Zhang junjun liu +2 位作者 Jing Wang Tean Ma Honghua Zhang 《Journal of Clinical and Nursing Research》 2024年第12期234-243,共10页
Objective:To retrieve,evaluate,and summarize the best evidence for puncture management during the early initiation stage of autologous arteriovenous fistula(AVF)in hemodialysis patients,providing a reference for clini... Objective:To retrieve,evaluate,and summarize the best evidence for puncture management during the early initiation stage of autologous arteriovenous fistula(AVF)in hemodialysis patients,providing a reference for clinical nursing practice.Method:Following the“6S”pyramid model system,evidence on puncture management during the initiation stage of AVF in hemodialysis patients was retrieved from domestic and international databases.The search included clinical decision-making tools,guidelines,evidence summaries,systematic reviews,and expert consensus.The retrieval period spanned from database inception to January 2023.Four researchers screened the literature,performed quality evaluations,and extracted and integrated the evidence.Results:A total of nine articles were included,comprising one clinical decision,five guidelines,one evidence summary,one systematic review,and one expert consensus.The evidence encompassed 18 key points across six areas:team building and personnel training,timing of initial puncture,pre-puncture evaluation,puncture methods,post-puncture pressure management,and management of puncture-related complications.Conclusion:Blood purification nursing staff should combine clinical scenarios with evidence-based medicine to adopt scientific,effective,and feasible puncture management strategies during the early initiation stage of AVF.This approach aims to better safeguard the patient’s vascular access and overall treatment outcomes. 展开更多
关键词 Autogenous arteriovenous fistula Early activation stage Puncture management Evidence summary Evidence-based nursing
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Mechanical behavior of coal under different mining rates:A case study from laboratory experiments to field testing 被引量:51
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作者 Mingzhong Gao Jing Xie +5 位作者 Yanan Gao Wenyong Wang Cong Li Bengao Yang junjun liu Heping Xie 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2021年第5期825-841,共17页
During the development of hot dry rock,the research on thermal fatigue damage caused by thermal shock of cold and heat cycles is the basis that ensures the long-term utilization of geothermal resources,but there are n... During the development of hot dry rock,the research on thermal fatigue damage caused by thermal shock of cold and heat cycles is the basis that ensures the long-term utilization of geothermal resources,but there are not enough relevant studies at present.Based on this,the thermal damage tests of granite at different temperatures(250,350,450°C)and quenching cycles(1,5,10,15 cycles)were carried out.Preliminary reveals the damage mechanism and heat transfer law of the quenching cycle effect on hot dry rock.The results show that with the increase of temperature and cycles,the uneven thermal expansion of minerals and the thermal shock caused by quenching promote the crack development of granite,resulting in the decrease of P-wave velocity,thermal conductivity and uniaxial compressive strength of granite.Meanwhile,the COMSOL was used to simulate the heat transfer of hot dry rock under different heat treatment conditions.It concluded that the increase in the number of quenching cycles reduced the heat transfer capacity of the granite,especially more than 10 quenching cycles,which also reflects that the thermal fatigue damage leads to a longer time for the temperature recovery of the hot dry rock mass.In addition,the three-dimensional nonlinear fitting relationship among thermal conductivity,temperature and cycle number was established for the first time,which can better reveal the change rule of thermal conductivity after quenching thermal fatigue effect of hot dry rock.The research results provide theoretical support for hot dry rock reservoir reconstruction and production efficiency evaluation. 展开更多
关键词 Mining rate Loading rate Fracture evolution Mining pressure Uniaxial compressive strength DIC
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The linkage maps of Dendrobium species based on RAPD and SRAP markers 被引量:27
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作者 Dawei Xue Shangguo Feng +6 位作者 Hongyan Zhao Hua Jiang Bo Shen Nongnong Shi Jiangjie Lu junjun liu Huizhong Wang 《Journal of Genetics and Genomics》 SCIE CAS CSCD 2010年第3期197-204,共8页
Dendrobium plants are used commonly as tonic herbs and health food in many Asian countries, especially in China. Here we report the genetic map construction of two Dendrobium species with a double pseudo-testcross str... Dendrobium plants are used commonly as tonic herbs and health food in many Asian countries, especially in China. Here we report the genetic map construction of two Dendrobium species with a double pseudo-testcross strategy using random amplified polymorphic DNA (RAPD) and sequence-related amplified polymorphism (SRAP) markers. A F1 mapping population of 90 individuals was developed from a cross between D. officinale and D. hercoglossum. A total of 307 markers, including 209 RAPD and 98 SRAP, were identified and used for genetic linkage group (LG) analysis. The D. officinale linkage map consisted of 11 major linkage groups and 3 doublets, which covered 629.4 cM by a total of 62 markers with an average locus distance of 11.2 cM between two adjacent markers. The D. hercoglos- sum linkage map contained 112 markers mapped on 15 major and 4 minor linkage groups, spanning a total length of 1,304.6 cM with an average distance of I 1.6 cM between two adjacent markers. The maps constructed in this study covered 92.7% and 82.7% of the D. hercoglossum and D. officinale genomes respectively, providing an important basis for the mapping of horticultural and medicinal traits and for the application of marker-assisted selection in Dendrobium breeding program. 展开更多
关键词 DENDROBIUM genetic linkage map RAPD SRAP
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基于磁共振成像乳腺癌远处转移预测模型的研究 被引量:6
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作者 汤加 马文娟 +2 位作者 刘君君 邵真真 刘佩芳 《中国肿瘤临床》 CAS CSCD 北大核心 2019年第7期337-341,共5页
目的:建立基于平扫磁共振成像(magnetic resonance imaging,MRI)和动态对比增强(dynamic contrast enhanced,DCE)-MRI影像特征参数的乳腺癌远处转移预测模型。方法:回顾性分析2011年1月至2016年12月3 032例于天津医科大学肿瘤医院行乳腺... 目的:建立基于平扫磁共振成像(magnetic resonance imaging,MRI)和动态对比增强(dynamic contrast enhanced,DCE)-MRI影像特征参数的乳腺癌远处转移预测模型。方法:回顾性分析2011年1月至2016年12月3 032例于天津医科大学肿瘤医院行乳腺MRI检查并经病理证实为乳腺浸润性癌患者的临床资料,根据纳入标准筛选出转移组93例和非转移组186例。分析转移组远处转移部位与分子分型的关系,同时对两组MRI影像特征进行单因素分析及多因素Logistics回归分析,获得独立预测因子并建立预测模型。结果:转移组中Luminal型、HER-2过表达型、三阴性乳腺癌最常见远处转移部位分别为骨、肝脏、肺脏。单因素分析结果显示,两组间的病变类型、是否多发、T1WI和T2WI信号均匀度及病灶最大径进行比较差异具有统计学意义(P<0.05)。多因素Logistics回归分析结果显示,病变类型、是否多发、T2WI信号均匀度及病灶最大径为独立预测因子。根据独立预测因子建立的预测模型准确率、敏感度、特异度和受试者工作特征曲线(receiver operating characteristic,ROC)下面积(area under receiver operating characteristic curve,AUC)分别为82.8%、85.7%、75.0%和0.801。结论:基于MRI影像特征的模型对预测乳腺癌远处转移具有潜在价值。 展开更多
关键词 乳腺癌 肿瘤转移 磁共振成像 预测 分子分型
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Work-family conflict and job burn-out among Chinese doctors:the mediating role of coping styles 被引量:7
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作者 Ling Chen junjun liu +10 位作者 Hailong Yang Hui Ma Hui Wang Yun Huang Hao Cheng Dianzhen Tang Miao liu Houyuan Luo Haitao Qu Diwen Shen Ning Zhang 《General Psychiatry》 CSCD 2018年第4期24-30,共7页
Background Burn-out among doctors threatens their own health, and that of their patients. To identify risk factors of the doctor burn-out is vital to improving their health and increasing the quality of healthcare s... Background Burn-out among doctors threatens their own health, and that of their patients. To identify risk factors of the doctor burn-out is vital to improving their health and increasing the quality of healthcare services. This study aims to explore the relationship between work-family confict (WFC) and burn-out among Chinese doctors and the mediating role of coping styles in this relationship.Methods A cross-sectional survey was conducted in China, with a questionnaire packet which consisted of the Chinese Maslach Burnout Inventory (CMBI), WFC Scale and the Simplifed Coping Style Questionnaire (SCSQ). A total of 2530 doctors participated in the survey. Correlation analysis was performed to explore the relationship between CMBI, WFC and SCSQ scores. A linear regression model was set to determine the mediating role of coping styles on the relationship between WFC and burn-out.Results Doctors who had higher scores on work interfering with family confict, reported more emotional exhaustion (r=0.514, P〈0.001) and had a sense of accomplishment (r= 0.149, P〈0.001). Simultaneously, family interfering with work (FIW) was positively associated with all dimensions of burn-out (r=0.213, 0.504, 0.088, respectively, P〈0.001). Coping styles had partial, complete and even mediating effects on the relationship between WFC and burn-out among Chinese doctors.Conclusions WFC was correlated with burn-out, and coping style was a mediator in this relationship among Chinese doctors. Coping style was a positive resource against burn-out. 展开更多
关键词 Work-family confict and job burn-out among Chinese doctors the mediating role of coping styles
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多模态超声检查对腹壁下动脉穿支皮瓣自体移植乳房再造术前血管评估研究 被引量:2
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作者 刘雪静 路红 +4 位作者 徐熠琳 李小康 季宇 刘君君 朱鹰 《中国肿瘤临床》 CAS CSCD 北大核心 2020年第24期1261-1264,共4页
目的:探讨多模态超声对腹壁下动脉穿支(deep inferior epigastric perforator,DIEP)皮瓣血管检查有效性,并分析穿支血管的影响因素。方法:纳入2013年2月至2018年10月43例于天津医科大学肿瘤医院使用DIEP皮瓣进行乳房再造术的女性乳腺癌... 目的:探讨多模态超声对腹壁下动脉穿支(deep inferior epigastric perforator,DIEP)皮瓣血管检查有效性,并分析穿支血管的影响因素。方法:纳入2013年2月至2018年10月43例于天津医科大学肿瘤医院使用DIEP皮瓣进行乳房再造术的女性乳腺癌患者,对穿支血管行术前常规及彩色多普勒超声检查,并在超声造影增强状态下行三维重建,直观显示穿支血管的走行分布情况,同时体表标注投影位置。结果:43例患者腹壁下动脉穿支主要分布在脐周5 cm范围内,每侧2~5支,其中28例呈不对称分布。DIEP穿支血管管径与患者腹壁脂肪层厚度呈正相关(r=0.436,P<0.05);血管收缩期峰值血流速度与穿支血管管径呈正相关(r=0.448,P<0.05)。43例患者行超声造影检查后彩色血流信号均能显著增强,其中39例经三维重建后能清晰显示穿支血管与腹壁下动脉主干的关系,4例穿支血管显示欠连续。结论:多模态超声检查在乳腺癌患者DIEP乳房再造术前评估穿支血管具有重要的应用价值,腹壁脂肪层厚度对优势血管的选择有一定影响。 展开更多
关键词 腹壁下动脉 穿支皮瓣 彩色多普勒 超声造影 三维重建
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The structure of 4-hydroxylphenylpyruvate dioxygenase complexed with 4-hydroxylphenylpyruvic acid reveals an unexpected inhibition mechanism 被引量:3
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作者 Xiaoning Wang Hongyan Lin +5 位作者 junjun liu Xinyun Zhao Xi Chen Wenchao Yang Guangfu Yang Chang-guo Zhan 《Chinese Chemical Letters》 CSCD 2021年第6期1920-1924,共5页
4-Hydroxyphenylpyruvate dioxygenase(HPPD)is an important target for both drug and pesticide discovery.As a typical Fe(II)-dependent dioxygenase,HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic a... 4-Hydroxyphenylpyruvate dioxygenase(HPPD)is an important target for both drug and pesticide discovery.As a typical Fe(II)-dependent dioxygenase,HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid(HPPA)to homogentisic acid(HGA).The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests.Recently,we reported the crystal structure of Arabidopsis thaliana HPPD(At HPPD)complexed with HPPA and a cobalt ion,which was supposed to mimic the pre-reactive structure of At HPPD-HPPA-Fe(II).Unexpectedly,the present study shows that the restored At HPPD-HPPA-Fe(II)complex is still nonreactive toward the bound dioxygen.QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring,and the residue Phe381 plays a key role in orienting the phenyl ring.Kinetic study on the F381 A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex.More importantly,the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors,suggesting that these inhibitors resist the association of dioxygen(and exert their inhibitory roles)in the same way as the HPPA.The present study provides insights into the inhibition mechanism of HPPD inhibitors. 展开更多
关键词 4-Hydroxyphenylpyruvate dioxygenase QM/MM calculation Potential surface scan Substrate self-inhibition
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Highly efficient solid-state luminescence of carbonized polymer dots without matrix
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作者 Rui Li junjun liu +3 位作者 Chunlei Xia Tanglue Feng Zhicheng Zhu Bai Yang 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第6期412-416,共5页
Development of high-performance solid state luminescent carbon-based nanomaterials remains challenging.Here,strong blue-green fluorescent carbonized polymer dots(CPDs)from o-aminobenzenethiol and thiosalicylic acid(o ... Development of high-performance solid state luminescent carbon-based nanomaterials remains challenging.Here,strong blue-green fluorescent carbonized polymer dots(CPDs)from o-aminobenzenethiol and thiosalicylic acid(o ABT-TSA-CPDs)with an absolute photoluminescence quantum yield(PLQY)of 76%in solid state without matrix were synthesized.Through adjusting the reaction temperature and time,the PL centers were proved to be carbon core state and surface state associated to carbonyl group which was the source of strong fluorescence emission in solid state.The mechanism of the unique phenomenon of enhanced emission from ethanol solution(PLQY=7%)to powder(PLQY=76%)was investigated by analyzing the chemical properties and structures of o ABT-TSA-CPDs at different temperatures and o ABT-TSACPDs/PVC composites,and was confirmed as fixation of PL centers. 展开更多
关键词 Carbonized polymer dots Solid-state fluorescence MATRIX-FREE High performance Enhanced photoluminescence quantum yield
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QM/MM study on the O_(2)activation reaction of 4-hydroxylphenyl pyruvate dioxygenase reveals a common mechanism forα-ketoglutarate dependent dioxygenase
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作者 Linhui Li Suitian Lai +6 位作者 Hongyan Lin Xinyun Zhao Xin Li Xi Chen junjun liu Guangfu Yang Changguo Zhan 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第5期461-465,共5页
The dioxygen activation catalyzed by 4-hydorxylphenyl pyruvate dioxygenase(HPPD)were reinvestigated by using hybrid quantum mechanics/molecular mechanics(QM/MM)approaches at the B3LYP/6-311++G(d,p):AMBER level.These s... The dioxygen activation catalyzed by 4-hydorxylphenyl pyruvate dioxygenase(HPPD)were reinvestigated by using hybrid quantum mechanics/molecular mechanics(QM/MM)approaches at the B3LYP/6-311++G(d,p):AMBER level.These studies showed that this reaction consisted of two steps including the dioxygen addition/decarboxylation and hetero O-O bond cleavage,where the first step was found to be rate-determining.The former step initially runs on a septet potential energy surface(PES),then switches to a quintet PES after crossing a septet/quintet minimum energy crossing point(MECP)5-7M2,whereas the rest step runs on the quintet PES.The reliability of our theoretical predictions is supported by the excellent agreement of the calculated free-energy barrier value of 16.9 kcal/mol with available experimental value of 16-17 kcal/mol.The present study challenges the widely accepted view which holds that the O2activation catalyzed byα-keto glutamate(α-KG)dioxygenase mainly runs on the quintet PES and provides new insight into the catalytic mechanism ofα-KG dioxygenase and/or other related Fe(Ⅱ)-dependent oxygenase. 展开更多
关键词 4-Hydroxylphenyl pyruvate dioxygenase O_(2)activation QM/MM Mechanism Minimum energy crossing point
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Preparation Process and Thin Layer Chromatography Identification of Wufang Babu Poultice
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作者 junjun liu Luyao XIE +2 位作者 Chuhui ZHOU Zhengteng YANG Xiongbin GUI 《Medicinal Plant》 CAS 2023年第4期58-61,共4页
[Objectives] To establish the process flow of preparation of Wufang Babu Poultice and the identification method of thin layer chromatography (TLC). [Methods] For the forming process of Wufang Babu Poultice, the prepar... [Objectives] To establish the process flow of preparation of Wufang Babu Poultice and the identification method of thin layer chromatography (TLC). [Methods] For the forming process of Wufang Babu Poultice, the preparation method of mixed pharmaceutical powder with suitable pharmaceutical excipients was adopted. Qualitative identification of medicinal materials in Wufang Babu Poultice (Strychni Semen, Rhei Radix Et Rhizoma, Dipsaci Radix, and Angelicae Sinensis Radix) was carried out by TLC. [Results] Mixed pharmaceutical powder mixed with glycerol, gelatin and other pharmaceutical excipients can be prepared for forming. The test solution chromatography of each medicinal material (Strychni Semen, Rhei Radix et Rhizoma, Dipsaci Radix, Angelicae Sinensis Radix) showed pigment spots of the same color at the same position as its corresponding control medicinal materials and reference chromatography, and the display was clear. [Conclusions] The preparation process is simple and feasible, and can be used as the forming process of Wufang Babu Poultice. The TLC determination method is simple to operate, has good specificity, and has no effect on negative results, and can be used for identification of Wufang Babu Poultice. 展开更多
关键词 Wufang Babu Poultice Preparation process Thin layer chromatography(TLC)
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An Efficient Webpage Classification Algorithm Based on LSH
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作者 junjun liu Haichun Sun Zhijun Ding 《国际计算机前沿大会会议论文集》 2015年第1期73-75,共3页
With the explosive growth of Internet information, it is more and more important to fetch real-time and related information. And it puts forward higher requirement on the speed of webpage classification which is one o... With the explosive growth of Internet information, it is more and more important to fetch real-time and related information. And it puts forward higher requirement on the speed of webpage classification which is one of common methods to retrieve and manage information. To get a more efficient classifier, this paper proposes a webpage classification method based on locality sensitive hash function. In which, three innovative modules including building feature dictionary, mapping feature vectors to fingerprints using Localitysensitive hashing, and extending webpage features are contained. The compare results show that the proposed algorithm has better performance in lower time than the naive bayes one. 展开更多
关键词 EXPLOSIVE growth Webpage classification Locality-sensitive HASHING FINGERPRINT EXTENDING webpage features
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基于Actor-Critic强化学习的投资与消费问题
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作者 刘峻均 徐海燕 卢相刚 《运筹与模糊学》 2025年第2期227-236,共10页
本文研究了基于Actor-Critic强化学习的最优资产与消费问题。为了描述个体对退休后实际消费水平较低的现象,我们假设个体在退休后的最低消费水平和养老金水平较低,金融市场的资产价格由马尔可夫链调节,考虑通胀因素、习惯消费水平,建立... 本文研究了基于Actor-Critic强化学习的最优资产与消费问题。为了描述个体对退休后实际消费水平较低的现象,我们假设个体在退休后的最低消费水平和养老金水平较低,金融市场的资产价格由马尔可夫链调节,考虑通胀因素、习惯消费水平,建立状态转换的财富模型。利用动态规划原理得到了Hamilton-Jacobi-Bellman(HJB)方程。由于扩散过程和状态切换,几乎不可能得到一个封闭形式的解。我们设计出一种基于Actor-Critic强化学习框架下的数值算法来解决最优控制问题,通过对财富过程、优化函数的离散化和对值函数、控制函数的神经网络参数化,采用策略梯度下降算法来改进控制函数,而对于值函数,采用一种TD误差方法来更新。最后是对该优化问题的数值结果展示。 展开更多
关键词 消费 投资 制度转换 强化学习 梯度下降
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