BACKGROUND Hepatectomy is the main treatment for patients with hepatocellular carcinoma(HCC)and it has a high possibility for long-term cure potential.But the postoperative mortality and recurrence rates remain high.S...BACKGROUND Hepatectomy is the main treatment for patients with hepatocellular carcinoma(HCC)and it has a high possibility for long-term cure potential.But the postoperative mortality and recurrence rates remain high.Since the long-term prognosis of HCC patients is strongly linked to liver function,preoperative assessment of liver function is very important for HCC patients.AIM To compare the predictive power of the modified Child-Pugh(MCP)and albumin-bilirubin(ALBI)grades for the long-term outcome of HCC.METHODS From January 2010 to June 2017,a total of 204 patients with HCC who underwent surgery at the Second Affiliated Hospital of Chongqing Medical University were enrolled in this retrospective study.Multivariate Cox regression analysis was used to determine the independent predictive factors of survival and relapse.The area under the curve(AUC)was used to evaluate the discriminative performance of the MCP grade and ALBI grade to predict the postoperative overall survival(OS)time and recurrence-free survival(RFS)time.RESULTS The median OS and RFS times were 44.0 mo(range:22.0-74.0 mo)and 22.0 mo(range:5.0-45.0 mo),respectively.The median OS and RFS times of MCP grades 1,2,and 3 patients were 60.0,39.0,and 18.0 mo(P<0.001)and 36.0,15.0,and 7.0 mo(P<0.001),respectively.The median OS and RFS times of ALBI grades 1,2,and 3 patients were 56.0,26.0,and 6.0 mo(P<0.001)and 25.0,10.0,and 3.0 mo(P=0.003),respectively.Both the MCP and ALBI grades were more accurate than the Child-Pugh grade for predicting long-term prognosis.Further analysis demonstrated that for both predicting OS and RFS,the MCP grade performed better than the ALBI grade(AUC:0.642 vs 0.605 for OS;0.659 vs 0.594 for RFS).CONCLUSION The MCP grade is more accurate than the ALBI grade for predicting long-term outcome of patients with HCC.展开更多
Graded modified Fenton’s （MF） oxidation is a strategy in which H 2 O 2 is added intermittently to prevent a sharp temperature increase and undesired soil sterilization at soil circumneutral pH versus adding the sam...Graded modified Fenton’s （MF） oxidation is a strategy in which H 2 O 2 is added intermittently to prevent a sharp temperature increase and undesired soil sterilization at soil circumneutral pH versus adding the same amount of H 2 O 2 continuously.The primary objective of the present study was to investigate whether a mild MF pre-oxidation such as a stepwise addition of H 2 O 2 can prevent sterilization and achieve a maximum degradation of tank oil in soil.Optimization experiments of graded MF oxidation were conducted using citric acid,oxalic acid and SOLV-X as iron chelators under different frequencies of H 2 O 2 addition.The results indicated that the activity order of iron chelates decreased as：citric acid （51%） SOLV-X （44%） oxalic acid （9%）,and citric acid was found to be an optimized iron chelating agent of graded MF oxidation.Three-time addition of H 2 O 2 was found to be favorable and economical due to decreasing total petroleum hydrocarbon removal from three time addition （51%） to five time addition （59%）.Biological experiments were conducted after graded MF oxidation of tank oil completed under optimum conditions mentioned above.After graded oxidation,substantially higher increase （31%） in microbial activity was observed with excessive H 2 O 2 （1470 mmol/L,the mol ratio of H 2 O 2：Fe 2＋ was 210：1） than that of non-oxidized soil.Removal efficiency of tank oil was up to 93% after four weeks.Especially,the oil fraction （C 10 –C 40 ） became more biodagradable after graded MF oxidation than its absence.Therefore,graded MF oxidation is a mild pretreatment to achieve an effective bioremediation of oil contaminated soil.展开更多
Rapid road infrastructure development due to an increasing demand of car users resulted in an increase in paved areas including road sites and suppression of green spaces. An integrated solution that can support a cou...Rapid road infrastructure development due to an increasing demand of car users resulted in an increase in paved areas including road sites and suppression of green spaces. An integrated solution that can support a country’s economic development without compromising water pollution is becoming inevitable. Recycling tyres in the form of crumb rubber tyres and mixing it into bituminous paving mixture can increase the recycling rate and minimize cost of incineration process. In dry mixing process, five (5) different variations of Open Graded Wearing (OGW) course road samples were made to make up 1.15 kg in each sample. Each OGW mix contained 4% - 6% bitumen Pen 60/ 70 and fixed 1% of crumb rubber tyres, making the percentage of crumb rubber tyres 14% - 20% of bituminous samples. Bitumen Pen 60/70 mixed with 20% crumb rubber tyres content met the PG 76 bitumen properties. Physical properties of OGW made from crumb rubber modified bitumen (CRMB) were better than standard bitumen only. In a separate water leachate test using ICP-OES equipment, heavy metal leachate of Cu(II), Pb(II), Zn(II) and Cd(II) were present in all OGW CRMB samples at increasing surrounding water temperature from 25℃ to 60℃. However all the heavy metal concentration was very low below the allowable limit of trade effluent standards into water course.展开更多
The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade ...The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.展开更多
BACKGROUND Modified albumin-bilirubin(mALBI)grade has been established as a survival determinant in hepatocellular carcinoma(HCC)patients who receive locoregional and targeted therapies.AIM To investigate whether mALB...BACKGROUND Modified albumin-bilirubin(mALBI)grade has been established as a survival determinant in hepatocellular carcinoma(HCC)patients who receive locoregional and targeted therapies.AIM To investigate whether mALBI could predict survival in unresectable HCC(uHCC)patients who were treated with atezolizumab plus bevacizumab(AB).METHODS A single-center,retrospective cohort study enrolled uHCC patients who received AB treatment between September 2020 and April 2023 and were followed up until June 2023.An association between mALBI and patient survival was determined using Cox proportional hazards analysis.RESULTS Of the 83 patients,67 patients(80.7%)were male with the mean age of 60.6 years.Among them,22 patients(26.5%)were classified as Barcelona Clinic Liver Cancer B,and 61 patients(73.5%)were classified as Barcelona Clinic Liver Cancer C.Cirrhosis was present in 76 patients(91.6%),with 58 patients classified as Child-Turcotte-Pugh(CTP)A and 18 as CTP B.The median overall survival(OS)and progression-free survival were 13.0 mo[95%confidence interval(CI):5.2-20.8]and 9.0 mo(95%CI:5.0-13.0),respectively.The patients were divided into two groups based on mALBI grades:42 patients(50.6%)in the mALBI 1+2a group;and 41 patients(49.4%)in the mALBI 2b+3 group.During the median follow-up period of 7.0 mo,the mALBI 1+2a group exhibited significantly better survival compared to the mALBI 2b+3 group,with a median OS that was not reached vs 3.0 mo(95%CI:0.1-6.0,P<0.001).In a subgroup of patients with CTP A,the mALBI 1+2a group also showed significantly longer survival compared to the mALBI 2b+3 group,with a median OS that was not reached vs 6.0 mo(95%CI:3.4-8.6,P<0.001).In the multivariate analysis,both CTP class and mALBI grade were independently associated with survival,with adjusted hazard ratios(95%CI)of 2.63(1.19-5.78,P=0.020)and 3.90(1.71-8.90,P=0.001),respectively.CONCLUSION mALBI grades can determine survival of uHCC patients receiving AB treatment,particularly those who have mildly impaired liver function.This highlights the importance of assessing mALBI before initiating AB treatment to optimize therapeutic efficacy in clinical practice.展开更多
A modified paving technique for automatic generation of all-quadrilateral mesh fromarbitrary 2-D geometry is presented. The generated mesh elementS are nearly square andperpendicular to boundaries. Aner the nodes and...A modified paving technique for automatic generation of all-quadrilateral mesh fromarbitrary 2-D geometry is presented. The generated mesh elementS are nearly square andperpendicular to boundaries. Aner the nodes and elementS formation is completed. a fully automaticgrading method is applied to increase the accuracy and reliability of engineering analysis. In thispaper, we mainly describe the theory of mathematical algorithm and present some examples ofautomatically generated mesh.展开更多
Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis r...Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.展开更多
A three-dimensional size-dependent layered model for simply-supported and func- tionally graded magnetoelectroelastic plates is presented based on the modified couple-stress theory. The functionally graded material is...A three-dimensional size-dependent layered model for simply-supported and func- tionally graded magnetoelectroelastic plates is presented based on the modified couple-stress theory. The functionally graded material is assumed to be exponential in the thickness direc- tion of the plate. The final governing equations are reduced to an eigensystem by expressing the extended displacements in terms of two-dimensional Fourier series. Using the propagator matrix method, the exact solutions of the magnetic, electric and mechanical fields of sandwich nanoplates with couple-stress effect and under the surface loads are derived. Numerical examples for two functionally graded sandwich plates made of piezoelectric BaTiO3 and magnetostrictive CoFe2O4 materials are presented to demonstrate the effect of the functional gradient factor and material length-scale parameter on the induced fields. The exact solutions presented in this work can also serve as benchmarks to various numerical methods for analyzing the size-dependent features in layered systems.展开更多
This paper focuses on the buckling behaviors of a micro-scaled bi-directional functionally graded （FG） beam with a rectangular cross-section, which is now widely used in fabricating components of micro-nano-electro-...This paper focuses on the buckling behaviors of a micro-scaled bi-directional functionally graded （FG） beam with a rectangular cross-section, which is now widely used in fabricating components of micro-nano-electro-mechanical systems （MEMS/NEMS） with a wide range of aspect ratios. Based on the modified couple stress theory and the principle of minimum potential energy, the governing equations and boundary conditions for a micro-structure-dependent beam theory are derived. The present beam theory incorporates different kinds of higher-order shear assumptions as well as the two familiar beam theories, namely, the Euler-Bernoulli and Timoshenko beam theories. A numerical solu- tion procedure, based on a generalized differential quadrature method （GDQM）, is used to calculate the results of the bi-directional FG beams. The effects of the two exponential FG indexes, the higher-order shear deformations, the length scale parameter, the geomet- ric dimensions, and the different boundary conditions on the critical buckling loads are studied in detail, by assuming that Young＇s modulus obeys an exponential distribution function in both length and thickness directions. To reach the desired critical buckling load, the appropriate exponential FG indexes and geometric shape of micro-beams can be designed according to the proposed theory.展开更多
A quasi-three dimensional model is proposed for the vibration analysis of functionally graded(FG)micro-beams with general boundary conditions based on the modified strain gradient theory.To consider the effects of tra...A quasi-three dimensional model is proposed for the vibration analysis of functionally graded(FG)micro-beams with general boundary conditions based on the modified strain gradient theory.To consider the effects of transverse shear and nor-mal deformations,a general displacement field is achieved by relaxing the assumption of the constant transverse displacement through the thickness.The conventional beam theories including the classical beam theory,the first-order beam theory,and the higher-order beam theory are regarded as the special cases of this model.The material proper-ties changing gradually along the thickness direction are calculated by the Mori-Tanaka scheme.The energy-based formulation is derived by a variational method integrated with the penalty function method,where the Chebyshev orthogonal polynomials are used as the basis function of the displacement variables.The formulation is validated by some comparative examples,and then the parametric studies are conducted to investigate the effects of transverse shear and normal deformations on vibration behaviors.展开更多
Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanoc...Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.展开更多
A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress the...A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress theory(MCST).The material properties are assumed to follow a power-law distribution along the chordwise direction.The model introduces one axial stretching variable and four transverse deflection variables including two pure bending components and two pure shear ones.The complex modal analysis and assumed mode methods are used to solve the governing equations of motion under different boundary conditions(BCs).Several examples are presented to verify the effectiveness of the developed model.By coupling the slenderness ratio,gradient index,rotation speed,and size effect with the pre-twisted angle,the effects of these factors on the thermomechanical vibration of the microbeam with different BCs are investigated.It is found that with the increase in the pre-twisted angle,the critical slenderness ratio and gradient index corresponding to the thermal instability of the microbeam increase,while the critical material length scale parameter(MLSP)and rotation speed decrease.The sensitivity of the fundamental frequency to temperature increases with the increasing slenderness ratio and gradient index,and decreases with the other increasing parameters.Moreover,the size effect can suppress the dynamic stiffening effect and enhance the Coriolis effect.Finally,the mode transition is quantitatively demonstrated by a modal assurance criterion(MAC).展开更多
目的:采用有限元分析方法,评估传统椎弓根轨迹置钉(traditional trajectory,TT)技术与改良皮质骨轨迹置钉(modified cortical bone trajectory,MCBT)技术在不同骨质疏松条件下的腰椎生物力学性能差异。方法:采用CT扫描技术获取骨质疏松...目的:采用有限元分析方法,评估传统椎弓根轨迹置钉(traditional trajectory,TT)技术与改良皮质骨轨迹置钉(modified cortical bone trajectory,MCBT)技术在不同骨质疏松条件下的腰椎生物力学性能差异。方法:采用CT扫描技术获取骨质疏松患者的腰椎断层图像,然后对L4腰椎结构进行三维重建并进行验证。通过改变骨密度,在骨量减少(A1)、中度骨质疏松(A2)、重度骨质疏松(A3)中分别构建两种钉道设计。一种在TT技术中使用传统双螺纹椎弓根螺钉(TT组),直径6mm,全长45mm;另一种在MCBT技术中使用的变径全皮质骨螺纹螺钉(MCBT组),直径4~5.5mm,全长45mm。分析不同骨质疏松条件下,两种钉道设计对螺钉轴向抗拔出力、螺钉稳定性(上、下、左、右工况的载荷位移比,即螺钉尾端向其垂直轴的上、下、左、右位移0.1mm时载荷值与其位移的比值)以及腰椎活动度(前屈、后伸、侧弯及轴向旋转时)的影响。结果:在轴向抗拔出力方面,MCBT组在A1、A2、A3中较TT组分别提高93.5%、96.5%、98.5%。在稳定性方面,上、下、左、右工况在A1、A2、A3下,MCBT组螺钉的载荷位移比,相对于TT组分别提升42.2%、40.8%、41.7%;49%、49%、51.5%;82.4%、81.5%、85.2%;73.1%、70.8%、72.5%。在腰椎活动度方面,前屈时在A1、A2、A3下,TT组较MCBT组增加25%、26.6%、28.7%;后伸时在A1和A2下,TT组比MCBT组增加24.5%、22.9%,而在A3下,差异无显著性意义(P>0.05);而在侧弯和轴向旋转时,MCBT组在A1、A2、A3下相比TT组仅有轻微增加(P>0.05)。结论:在不同程度骨质疏松分级下,MCBT技术仅在椎体轴向旋转和侧屈时的稳定性上弱于TT技术,但在轴向抗拔出力、螺钉稳定性及椎体前屈、后伸时的稳定性上优于TT技术。展开更多
基金Supported by National Natural Science Foundation of China,No.81572888
文摘BACKGROUND Hepatectomy is the main treatment for patients with hepatocellular carcinoma(HCC)and it has a high possibility for long-term cure potential.But the postoperative mortality and recurrence rates remain high.Since the long-term prognosis of HCC patients is strongly linked to liver function,preoperative assessment of liver function is very important for HCC patients.AIM To compare the predictive power of the modified Child-Pugh(MCP)and albumin-bilirubin(ALBI)grades for the long-term outcome of HCC.METHODS From January 2010 to June 2017,a total of 204 patients with HCC who underwent surgery at the Second Affiliated Hospital of Chongqing Medical University were enrolled in this retrospective study.Multivariate Cox regression analysis was used to determine the independent predictive factors of survival and relapse.The area under the curve(AUC)was used to evaluate the discriminative performance of the MCP grade and ALBI grade to predict the postoperative overall survival(OS)time and recurrence-free survival(RFS)time.RESULTS The median OS and RFS times were 44.0 mo(range:22.0-74.0 mo)and 22.0 mo(range:5.0-45.0 mo),respectively.The median OS and RFS times of MCP grades 1,2,and 3 patients were 60.0,39.0,and 18.0 mo(P<0.001)and 36.0,15.0,and 7.0 mo(P<0.001),respectively.The median OS and RFS times of ALBI grades 1,2,and 3 patients were 56.0,26.0,and 6.0 mo(P<0.001)and 25.0,10.0,and 3.0 mo(P=0.003),respectively.Both the MCP and ALBI grades were more accurate than the Child-Pugh grade for predicting long-term prognosis.Further analysis demonstrated that for both predicting OS and RFS,the MCP grade performed better than the ALBI grade(AUC:0.642 vs 0.605 for OS;0.659 vs 0.594 for RFS).CONCLUSION The MCP grade is more accurate than the ALBI grade for predicting long-term outcome of patients with HCC.
基金supported by the Program of In-ternational S&T Cooperation(No.2010 DFA 94550,2010KW-24-1)the National Natural Science Founda-tion of China(No.50830303)+1 种基金the Major Science and Technology Program for Water Pollution Control and Treatment(No.2009ZX07317-007-001)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT0853)
文摘Graded modified Fenton’s （MF） oxidation is a strategy in which H 2 O 2 is added intermittently to prevent a sharp temperature increase and undesired soil sterilization at soil circumneutral pH versus adding the same amount of H 2 O 2 continuously.The primary objective of the present study was to investigate whether a mild MF pre-oxidation such as a stepwise addition of H 2 O 2 can prevent sterilization and achieve a maximum degradation of tank oil in soil.Optimization experiments of graded MF oxidation were conducted using citric acid,oxalic acid and SOLV-X as iron chelators under different frequencies of H 2 O 2 addition.The results indicated that the activity order of iron chelates decreased as：citric acid （51%） SOLV-X （44%） oxalic acid （9%）,and citric acid was found to be an optimized iron chelating agent of graded MF oxidation.Three-time addition of H 2 O 2 was found to be favorable and economical due to decreasing total petroleum hydrocarbon removal from three time addition （51%） to five time addition （59%）.Biological experiments were conducted after graded MF oxidation of tank oil completed under optimum conditions mentioned above.After graded oxidation,substantially higher increase （31%） in microbial activity was observed with excessive H 2 O 2 （1470 mmol/L,the mol ratio of H 2 O 2：Fe 2＋ was 210：1） than that of non-oxidized soil.Removal efficiency of tank oil was up to 93% after four weeks.Especially,the oil fraction （C 10 –C 40 ） became more biodagradable after graded MF oxidation than its absence.Therefore,graded MF oxidation is a mild pretreatment to achieve an effective bioremediation of oil contaminated soil.
文摘Rapid road infrastructure development due to an increasing demand of car users resulted in an increase in paved areas including road sites and suppression of green spaces. An integrated solution that can support a country’s economic development without compromising water pollution is becoming inevitable. Recycling tyres in the form of crumb rubber tyres and mixing it into bituminous paving mixture can increase the recycling rate and minimize cost of incineration process. In dry mixing process, five (5) different variations of Open Graded Wearing (OGW) course road samples were made to make up 1.15 kg in each sample. Each OGW mix contained 4% - 6% bitumen Pen 60/ 70 and fixed 1% of crumb rubber tyres, making the percentage of crumb rubber tyres 14% - 20% of bituminous samples. Bitumen Pen 60/70 mixed with 20% crumb rubber tyres content met the PG 76 bitumen properties. Physical properties of OGW made from crumb rubber modified bitumen (CRMB) were better than standard bitumen only. In a separate water leachate test using ICP-OES equipment, heavy metal leachate of Cu(II), Pb(II), Zn(II) and Cd(II) were present in all OGW CRMB samples at increasing surrounding water temperature from 25℃ to 60℃. However all the heavy metal concentration was very low below the allowable limit of trade effluent standards into water course.
基金Funded in Part by the National Natural Science Foundation of China (No. 50878054)
文摘The objective of this research was to show a way to conduct rejuvenation of aged polymer modified asphalt binder（PMB） successfully.To fully evaluate and understand the rejuvenation of aged PMB,the Penetration grade tests including penetration,soften point,ductility and elastic recovery and SuperpaveTM PG grade tests including DSR,BBR and DDT were conducted.The rejuvenation effect of aged PMB by utilizing a fluid recycling agent in common use for binder rejuvenation was evaluated.And then the compound rejuvenation effect of aged PMB by utilizing the recycling agent with a new modifying additive for binder modification was evaluated.The experimental results indicated that the recycling agent in common use currently does not apply to polymer modified asphalt binder rejuvenation.But the recycling agent together with the modifying additive can restore the characteristics of aged polymer modified binder very well.Therefore,compound rejuvenation of polymer modified asphalt binder is recommended.
文摘BACKGROUND Modified albumin-bilirubin(mALBI)grade has been established as a survival determinant in hepatocellular carcinoma(HCC)patients who receive locoregional and targeted therapies.AIM To investigate whether mALBI could predict survival in unresectable HCC(uHCC)patients who were treated with atezolizumab plus bevacizumab(AB).METHODS A single-center,retrospective cohort study enrolled uHCC patients who received AB treatment between September 2020 and April 2023 and were followed up until June 2023.An association between mALBI and patient survival was determined using Cox proportional hazards analysis.RESULTS Of the 83 patients,67 patients(80.7%)were male with the mean age of 60.6 years.Among them,22 patients(26.5%)were classified as Barcelona Clinic Liver Cancer B,and 61 patients(73.5%)were classified as Barcelona Clinic Liver Cancer C.Cirrhosis was present in 76 patients(91.6%),with 58 patients classified as Child-Turcotte-Pugh(CTP)A and 18 as CTP B.The median overall survival(OS)and progression-free survival were 13.0 mo[95%confidence interval(CI):5.2-20.8]and 9.0 mo(95%CI:5.0-13.0),respectively.The patients were divided into two groups based on mALBI grades:42 patients(50.6%)in the mALBI 1+2a group;and 41 patients(49.4%)in the mALBI 2b+3 group.During the median follow-up period of 7.0 mo,the mALBI 1+2a group exhibited significantly better survival compared to the mALBI 2b+3 group,with a median OS that was not reached vs 3.0 mo(95%CI:0.1-6.0,P<0.001).In a subgroup of patients with CTP A,the mALBI 1+2a group also showed significantly longer survival compared to the mALBI 2b+3 group,with a median OS that was not reached vs 6.0 mo(95%CI:3.4-8.6,P<0.001).In the multivariate analysis,both CTP class and mALBI grade were independently associated with survival,with adjusted hazard ratios(95%CI)of 2.63(1.19-5.78,P=0.020)and 3.90(1.71-8.90,P=0.001),respectively.CONCLUSION mALBI grades can determine survival of uHCC patients receiving AB treatment,particularly those who have mildly impaired liver function.This highlights the importance of assessing mALBI before initiating AB treatment to optimize therapeutic efficacy in clinical practice.
文摘A modified paving technique for automatic generation of all-quadrilateral mesh fromarbitrary 2-D geometry is presented. The generated mesh elementS are nearly square andperpendicular to boundaries. Aner the nodes and elementS formation is completed. a fully automaticgrading method is applied to increase the accuracy and reliability of engineering analysis. In thispaper, we mainly describe the theory of mathematical algorithm and present some examples ofautomatically generated mesh.
文摘Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 11262012, 11502123, 11172273） and the Natural Science Foundation of Inner Mongolia Autonomous Region of China （Grant No. 2015JQ01）.
文摘A three-dimensional size-dependent layered model for simply-supported and func- tionally graded magnetoelectroelastic plates is presented based on the modified couple-stress theory. The functionally graded material is assumed to be exponential in the thickness direc- tion of the plate. The final governing equations are reduced to an eigensystem by expressing the extended displacements in terms of two-dimensional Fourier series. Using the propagator matrix method, the exact solutions of the magnetic, electric and mechanical fields of sandwich nanoplates with couple-stress effect and under the surface loads are derived. Numerical examples for two functionally graded sandwich plates made of piezoelectric BaTiO3 and magnetostrictive CoFe2O4 materials are presented to demonstrate the effect of the functional gradient factor and material length-scale parameter on the induced fields. The exact solutions presented in this work can also serve as benchmarks to various numerical methods for analyzing the size-dependent features in layered systems.
基金supported by the National Natural Science Foundation of China(Nos.51375184 and 51605172)the Fundamental Research Funds for the Central Universities(No.2015MS014)
文摘This paper focuses on the buckling behaviors of a micro-scaled bi-directional functionally graded （FG） beam with a rectangular cross-section, which is now widely used in fabricating components of micro-nano-electro-mechanical systems （MEMS/NEMS） with a wide range of aspect ratios. Based on the modified couple stress theory and the principle of minimum potential energy, the governing equations and boundary conditions for a micro-structure-dependent beam theory are derived. The present beam theory incorporates different kinds of higher-order shear assumptions as well as the two familiar beam theories, namely, the Euler-Bernoulli and Timoshenko beam theories. A numerical solu- tion procedure, based on a generalized differential quadrature method （GDQM）, is used to calculate the results of the bi-directional FG beams. The effects of the two exponential FG indexes, the higher-order shear deformations, the length scale parameter, the geomet- ric dimensions, and the different boundary conditions on the critical buckling loads are studied in detail, by assuming that Young＇s modulus obeys an exponential distribution function in both length and thickness directions. To reach the desired critical buckling load, the appropriate exponential FG indexes and geometric shape of micro-beams can be designed according to the proposed theory.
基金Project supported by the National Natural Science Foundation of China(Nos.51805250 and 11602145)the Natural Science Foundation of Jiangsu Province of China(No.BK20180429)+1 种基金the China Postdoctoral Science Foundation(No.2019M660114)the Jiangsu Planned Projects for Postdoctoral Research Funds of China(No.2019K054)。
文摘A quasi-three dimensional model is proposed for the vibration analysis of functionally graded(FG)micro-beams with general boundary conditions based on the modified strain gradient theory.To consider the effects of transverse shear and nor-mal deformations,a general displacement field is achieved by relaxing the assumption of the constant transverse displacement through the thickness.The conventional beam theories including the classical beam theory,the first-order beam theory,and the higher-order beam theory are regarded as the special cases of this model.The material proper-ties changing gradually along the thickness direction are calculated by the Mori-Tanaka scheme.The energy-based formulation is derived by a variational method integrated with the penalty function method,where the Chebyshev orthogonal polynomials are used as the basis function of the displacement variables.The formulation is validated by some comparative examples,and then the parametric studies are conducted to investigate the effects of transverse shear and normal deformations on vibration behaviors.
文摘Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.
基金the National Natural Science Foundation of China(Nos.11602204 and 12102373)the Fundamental Research Funds for the Central Universities of China(Nos.2682022ZTPY081 and 2682022CX056)the Natural Science Foundation of Sichuan Province of China(Nos.2023NSFSC0849,2023NSFSC1300,2022NSFSC1938,and 2022NSFSC2003)。
文摘A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress theory(MCST).The material properties are assumed to follow a power-law distribution along the chordwise direction.The model introduces one axial stretching variable and four transverse deflection variables including two pure bending components and two pure shear ones.The complex modal analysis and assumed mode methods are used to solve the governing equations of motion under different boundary conditions(BCs).Several examples are presented to verify the effectiveness of the developed model.By coupling the slenderness ratio,gradient index,rotation speed,and size effect with the pre-twisted angle,the effects of these factors on the thermomechanical vibration of the microbeam with different BCs are investigated.It is found that with the increase in the pre-twisted angle,the critical slenderness ratio and gradient index corresponding to the thermal instability of the microbeam increase,while the critical material length scale parameter(MLSP)and rotation speed decrease.The sensitivity of the fundamental frequency to temperature increases with the increasing slenderness ratio and gradient index,and decreases with the other increasing parameters.Moreover,the size effect can suppress the dynamic stiffening effect and enhance the Coriolis effect.Finally,the mode transition is quantitatively demonstrated by a modal assurance criterion(MAC).
文摘目的:采用有限元分析方法,评估传统椎弓根轨迹置钉(traditional trajectory,TT)技术与改良皮质骨轨迹置钉(modified cortical bone trajectory,MCBT)技术在不同骨质疏松条件下的腰椎生物力学性能差异。方法:采用CT扫描技术获取骨质疏松患者的腰椎断层图像,然后对L4腰椎结构进行三维重建并进行验证。通过改变骨密度,在骨量减少(A1)、中度骨质疏松(A2)、重度骨质疏松(A3)中分别构建两种钉道设计。一种在TT技术中使用传统双螺纹椎弓根螺钉(TT组),直径6mm,全长45mm;另一种在MCBT技术中使用的变径全皮质骨螺纹螺钉(MCBT组),直径4~5.5mm,全长45mm。分析不同骨质疏松条件下,两种钉道设计对螺钉轴向抗拔出力、螺钉稳定性(上、下、左、右工况的载荷位移比,即螺钉尾端向其垂直轴的上、下、左、右位移0.1mm时载荷值与其位移的比值)以及腰椎活动度(前屈、后伸、侧弯及轴向旋转时)的影响。结果:在轴向抗拔出力方面,MCBT组在A1、A2、A3中较TT组分别提高93.5%、96.5%、98.5%。在稳定性方面,上、下、左、右工况在A1、A2、A3下,MCBT组螺钉的载荷位移比,相对于TT组分别提升42.2%、40.8%、41.7%;49%、49%、51.5%;82.4%、81.5%、85.2%;73.1%、70.8%、72.5%。在腰椎活动度方面,前屈时在A1、A2、A3下,TT组较MCBT组增加25%、26.6%、28.7%;后伸时在A1和A2下,TT组比MCBT组增加24.5%、22.9%,而在A3下,差异无显著性意义(P>0.05);而在侧弯和轴向旋转时,MCBT组在A1、A2、A3下相比TT组仅有轻微增加(P>0.05)。结论:在不同程度骨质疏松分级下,MCBT技术仅在椎体轴向旋转和侧屈时的稳定性上弱于TT技术,但在轴向抗拔出力、螺钉稳定性及椎体前屈、后伸时的稳定性上优于TT技术。
