AIM: To investigate the reliability of massive hepatectomy models by using clip techniques. METHODS: We analyzed anatomical findings in 100 mice following massive hepatectomy induced by liver reduction > 70%. The i...AIM: To investigate the reliability of massive hepatectomy models by using clip techniques. METHODS: We analyzed anatomical findings in 100 mice following massive hepatectomy induced by liver reduction > 70%. The impact of various factors in the different models was also analyzed, including learning curves, operative time, survival curves, and histopathological findings.RESULTS: According to anatomical results, models with 75%, 80%, and 90% hepatectomy produced massive hepatectomy. Learning curves and operative times were most optimal with the clip technique. Each hepatectomy performed using the clip technique produced a reasonable survival curve, and there were no differences in histopathological findings between the suture and clip techniques. CONCLUSION: Massive hepatectomy by the clip technique is simple and can provide reliable and relevant data.展开更多
In this paper, a robust digital watermarking method against shearing based on Haar orthogonal function system was introduced. The proposed method adopted the complete generalized orthogonal properties of Haar ortbogon...In this paper, a robust digital watermarking method against shearing based on Haar orthogonal function system was introduced. The proposed method adopted the complete generalized orthogonal properties of Haar ortbogonal function system to achieve the piece-based orthogonal transform on the image. The significant middle frequency coefficients in the transformation matrix are picked up, based on characteristics of the image visual system and the Haar orthogonal transform. The watermark is adoptively weighed to the middle frequency matrix. The method improves the validity of watermarking and shows excellent advantage against shearing attack. Experimental results show that the Haar orthogonal function system based watermark approach can provide an excellent protection under geometric attacks.展开更多
This paper studies the motion of novel manipulator that can be used in the structure of stone protectors of soil tillage implements. According to the virtual reality technology-based method the technology of compositi...This paper studies the motion of novel manipulator that can be used in the structure of stone protectors of soil tillage implements. According to the virtual reality technology-based method the technology of composition of the virtual model of a manipulator and its positions in the working process are described in details. This virtual model is used for composition the video clip, simulating the motion of novel manipulator, which three points are moving along two lines and one curve. The results obtained and the computer program realizing the virtual reality technology-based study of the working process of the virtual manipulators for stone protectors can be used by designers of stone protectors for soil tillage implements.展开更多
Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechan...Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechanism,the complete deformation process of deep rock mass,with a great emphasis on local shear deformation stage,was analyzed in detail.The quasi continuous shear deformation of the deep rock mass is described by a combination of smooth functions:the averaged distribution of the original deformation field,and the local discontinuities along the slip lines.Hence,an elasto-plastic model is established for the shear deformation process,in which the rotational displacement is taken into account as well as the translational component.Numerical analysis method was developed for case study.Deformation process of a tunnel under high earth stress was investigated for verification.展开更多
The relationship between the strain rate field observed by GPS and global distribution of strong earthquakes is analyzed in this work. How do we recognize the characteristics of global seismic activities with space ob...The relationship between the strain rate field observed by GPS and global distribution of strong earthquakes is analyzed in this work. How do we recognize the characteristics of global seismic activities with space observation technology? A preliminary model of Cellular Automata that could simulate the global seismic activities both in time and space has been established based on the results of global strain rate field provided by the GSRM Program. The grid of the model is evenly divided,which is consistent with that of GSRM.The status of each cell is its strain state,and is adjusted according to the evolution rules.Maximum shear strain criterion is adopted in the evolution of the Cellular Automata. The threshold for cells in surface expansion is 80% of that for those in compression. The preliminary model could in general simulate the main characteristics of the distribution of the global seismic activities. It could exhibit in general the global distribution of weak and active tectonic activities. Although the preliminary Cellular Automata model needs to be improved in many aspects,the result suggests the possibility of modeling the general features of rather complicated global seismic activities based on the strain rates obtained by GPS and other observations.展开更多
In shale gas fracking, the stimulated natural fracture system is often critical to the gas production. In this paper, we present the results of state-of-the-art modeling of a detailed parametric evolution of the shear...In shale gas fracking, the stimulated natural fracture system is often critical to the gas production. In this paper, we present the results of state-of-the-art modeling of a detailed parametric evolution of the shear stimulation effect in discrete fracture network(DFN) formations. Two-dimensional computational modeling studies have been used in an attempt towards understanding how naturally fractured reservoirs response in hydraulic fracturing. Simulations were conducted as a function of:(1) the in-situ stress ratio;(2) internal friction angle of DFN;(3) DFN orientation with the stress field; and(4) operational vari- ables such as injection rate. A sensitivity study reveals a number of interesting observations resulting from these parameters on the shear stimulation in natural fracture system. This work strongly links the production technology, geomechanical evaluation and aids in the understanding and optimization of hydraulic fracturing simulations in naturally fractured reservoirs.展开更多
Blood pumps have been adopted to treat heart failure over the past decades. A novel blood pump adopting the rotor with splitter blades and tandem cascade stator was developed recently. A particle image velocimetry （...Blood pumps have been adopted to treat heart failure over the past decades. A novel blood pump adopting the rotor with splitter blades and tandem cascade stator was developed recently. A particle image velocimetry （P1V） experiment was carried out to verify the design of the blood pump based on computational fluid dynamics （CFD） and further analyze the flow properties in the rotor and stator. The original sized pump model with an acrylic housing and an experiment loop were constructed to perform the optical measurement. The PIV testing was carried out at the rotational speed of 6952±50 r/rain with the flow rate of 3.1 l/rain and at 8186±50 r/min with 3.5 l/rain, respectively. The velocity and the Reynolds shear stress distributions were investigated by PIV and CFD, and the comparisons between them will be helpful for the future blood pump design.展开更多
This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology.Microflu...This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology.Microfluidic chip was fabricated by soft lithograph; Endothelial microfluidic chip was constructed by optimizing types of the extracellular matrix proteins modified in the microchannel and cell incubation time;human umbilical vein endothelial cells EA.Hy926 lined in the microchannel were exposed to fluid shear stress of 1.68 dynes/cm^2 and 8.4 dynes/cm^2 respectively.Meanwhile,adhesion between EA.Hy926 cells and leukocyte was induced by TNF-αunder a flow condition.EA.Hy926 cell cultured in the static condition was used as control group.The numbers of fluorescently-labeled leukocyte in microchannel were counted to quantize the adhesion level between EA.Hy926 cells and leukocyte; cell immunofluorescence technique was used to detect the intercellular adhesion molecule(ICAM-1) expression.The constructed endothelial microfluidic chip can afford to the fluid shear stress and respond to exogenous stimulus of TNF-α; compared with the adhesion numbers of leukocyte in control group,adhesion between EA.Hy926 cells exposed to low fluid shear stress and leukocyte was reduced under the stimulus of TNF-α at a concentration of 10 ng/ml(P<0.05); leukocyte adhesion with EA.Hy926 cells exposed to high fluid shear stress was reduced significantly than EA.Hy926 cells in control group and EA.1Hy926 cells exposed to low fluid shear stress(P<0.01); the regulation mechanism of fluid shear stress to the adhesion between EA.Hy926 cells and leukocyte induced by TNF-αwas through the way of ICAM-1.The endothelial microfluidic chip fabricated in this paper could be used to study the functions of endothelial cell in vitro and provide a new technical platform for exploring the pathophysiology of the related cardiovascular system diseases under a flow environment.展开更多
The hemodynamics of intracranial aneurysm(IA)comprises complex transient flow patterns that affect its growth and rupture.Owing to the combined effects of geometrical factors and pulsatile flow conditions,the transien...The hemodynamics of intracranial aneurysm(IA)comprises complex transient flow patterns that affect its growth and rupture.Owing to the combined effects of geometrical factors and pulsatile flow conditions,the transient flow patterns in the IA are still unclear.The purpose of this work is to reveal the effect of the aspect ratio(AR,sac height/neck width)on the evolution of the internal flow patterns and the hemodynamics of the IA.We proposed an easy method to fabricate three simplified elastic IA models and measured the transient flow characteristics by using particle image velocimetry(PIV).Transient vortex structures in the IA modes during a cardiac cycle were systemically measured and many new flow phenomena were found,including the vortex morphology(size,structure,and core location),a high-speed jet,wall compliance effects,and three flow modes during retrograde flow phase.The results show that the AR of the IA affects the transient flow patterns as well as the wall shear stress(WSS)in complex ways.The results could deepen our understanding of the transient flow behaviors in IA and guide related clinical studies.展开更多
基金Supported by Grants to Justin H Nguyen from the Deason Foundation, Sandra and Eugene Davenport, Mayo Clinic CD CRT-II and NIH R01NS051646-01A2partial grant to Tomohide Hori from the Uehara Memorial Foundation, No. 200940051, Tokyo 171-0033, Japan
文摘AIM: To investigate the reliability of massive hepatectomy models by using clip techniques. METHODS: We analyzed anatomical findings in 100 mice following massive hepatectomy induced by liver reduction > 70%. The impact of various factors in the different models was also analyzed, including learning curves, operative time, survival curves, and histopathological findings.RESULTS: According to anatomical results, models with 75%, 80%, and 90% hepatectomy produced massive hepatectomy. Learning curves and operative times were most optimal with the clip technique. Each hepatectomy performed using the clip technique produced a reasonable survival curve, and there were no differences in histopathological findings between the suture and clip techniques. CONCLUSION: Massive hepatectomy by the clip technique is simple and can provide reliable and relevant data.
文摘In this paper, a robust digital watermarking method against shearing based on Haar orthogonal function system was introduced. The proposed method adopted the complete generalized orthogonal properties of Haar ortbogonal function system to achieve the piece-based orthogonal transform on the image. The significant middle frequency coefficients in the transformation matrix are picked up, based on characteristics of the image visual system and the Haar orthogonal transform. The watermark is adoptively weighed to the middle frequency matrix. The method improves the validity of watermarking and shows excellent advantage against shearing attack. Experimental results show that the Haar orthogonal function system based watermark approach can provide an excellent protection under geometric attacks.
文摘This paper studies the motion of novel manipulator that can be used in the structure of stone protectors of soil tillage implements. According to the virtual reality technology-based method the technology of composition of the virtual model of a manipulator and its positions in the working process are described in details. This virtual model is used for composition the video clip, simulating the motion of novel manipulator, which three points are moving along two lines and one curve. The results obtained and the computer program realizing the virtual reality technology-based study of the working process of the virtual manipulators for stone protectors can be used by designers of stone protectors for soil tillage implements.
基金Project(50825403) supported by the National Science Fund for Distinguished Young ScholarsProject(2010CB732003) supported by the National Key Basic Research Program of ChinaProject(51021001) supported by the Science Fund for Creative Research Group of the National Natural Science Foundation of China
文摘Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechanism,the complete deformation process of deep rock mass,with a great emphasis on local shear deformation stage,was analyzed in detail.The quasi continuous shear deformation of the deep rock mass is described by a combination of smooth functions:the averaged distribution of the original deformation field,and the local discontinuities along the slip lines.Hence,an elasto-plastic model is established for the shear deformation process,in which the rotational displacement is taken into account as well as the translational component.Numerical analysis method was developed for case study.Deformation process of a tunnel under high earth stress was investigated for verification.
基金sponsored by the National Key Techonology R&D Program(2012BAK19B01)the National Natural Foundation of China(41274098)
文摘The relationship between the strain rate field observed by GPS and global distribution of strong earthquakes is analyzed in this work. How do we recognize the characteristics of global seismic activities with space observation technology? A preliminary model of Cellular Automata that could simulate the global seismic activities both in time and space has been established based on the results of global strain rate field provided by the GSRM Program. The grid of the model is evenly divided,which is consistent with that of GSRM.The status of each cell is its strain state,and is adjusted according to the evolution rules.Maximum shear strain criterion is adopted in the evolution of the Cellular Automata. The threshold for cells in surface expansion is 80% of that for those in compression. The preliminary model could in general simulate the main characteristics of the distribution of the global seismic activities. It could exhibit in general the global distribution of weak and active tectonic activities. Although the preliminary Cellular Automata model needs to be improved in many aspects,the result suggests the possibility of modeling the general features of rather complicated global seismic activities based on the strain rates obtained by GPS and other observations.
基金supported by the National Natural Science Foundation of China(Grant Nos.4122790141330643&41502294)+2 种基金China Postdoctoral Science Foundation Funded Project(Grant No.2015M571118)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB10030000XDB10030300&XDB10050400)
文摘In shale gas fracking, the stimulated natural fracture system is often critical to the gas production. In this paper, we present the results of state-of-the-art modeling of a detailed parametric evolution of the shear stimulation effect in discrete fracture network(DFN) formations. Two-dimensional computational modeling studies have been used in an attempt towards understanding how naturally fractured reservoirs response in hydraulic fracturing. Simulations were conducted as a function of:(1) the in-situ stress ratio;(2) internal friction angle of DFN;(3) DFN orientation with the stress field; and(4) operational vari- ables such as injection rate. A sensitivity study reveals a number of interesting observations resulting from these parameters on the shear stimulation in natural fracture system. This work strongly links the production technology, geomechanical evaluation and aids in the understanding and optimization of hydraulic fracturing simulations in naturally fractured reservoirs.
基金supported by the National Natural Science Foundation of China (Grant Nos.50676004 and 50736007)the Science Foundation of Fuwai hospital (Grant No:2009F-010)the Key Subject Foundation of Beijing:Fluid Machinery and Engineering
文摘Blood pumps have been adopted to treat heart failure over the past decades. A novel blood pump adopting the rotor with splitter blades and tandem cascade stator was developed recently. A particle image velocimetry （P1V） experiment was carried out to verify the design of the blood pump based on computational fluid dynamics （CFD） and further analyze the flow properties in the rotor and stator. The original sized pump model with an acrylic housing and an experiment loop were constructed to perform the optical measurement. The PIV testing was carried out at the rotational speed of 6952±50 r/rain with the flow rate of 3.1 l/rain and at 8186±50 r/min with 3.5 l/rain, respectively. The velocity and the Reynolds shear stress distributions were investigated by PIV and CFD, and the comparisons between them will be helpful for the future blood pump design.
文摘This paper aims to the research of the impact of fluid shear stress on the adhesion between vascular endothelial cells and leukocyte induced by tumor necrosis factor-α(TNF-α) by microfliudic chip technology.Microfluidic chip was fabricated by soft lithograph; Endothelial microfluidic chip was constructed by optimizing types of the extracellular matrix proteins modified in the microchannel and cell incubation time;human umbilical vein endothelial cells EA.Hy926 lined in the microchannel were exposed to fluid shear stress of 1.68 dynes/cm^2 and 8.4 dynes/cm^2 respectively.Meanwhile,adhesion between EA.Hy926 cells and leukocyte was induced by TNF-αunder a flow condition.EA.Hy926 cell cultured in the static condition was used as control group.The numbers of fluorescently-labeled leukocyte in microchannel were counted to quantize the adhesion level between EA.Hy926 cells and leukocyte; cell immunofluorescence technique was used to detect the intercellular adhesion molecule(ICAM-1) expression.The constructed endothelial microfluidic chip can afford to the fluid shear stress and respond to exogenous stimulus of TNF-α; compared with the adhesion numbers of leukocyte in control group,adhesion between EA.Hy926 cells exposed to low fluid shear stress and leukocyte was reduced under the stimulus of TNF-α at a concentration of 10 ng/ml(P<0.05); leukocyte adhesion with EA.Hy926 cells exposed to high fluid shear stress was reduced significantly than EA.Hy926 cells in control group and EA.1Hy926 cells exposed to low fluid shear stress(P<0.01); the regulation mechanism of fluid shear stress to the adhesion between EA.Hy926 cells and leukocyte induced by TNF-αwas through the way of ICAM-1.The endothelial microfluidic chip fabricated in this paper could be used to study the functions of endothelial cell in vitro and provide a new technical platform for exploring the pathophysiology of the related cardiovascular system diseases under a flow environment.
基金supported by the National Natural Science Foundation of China(Grant Nos:12172017 and 11872083)Project of Beijing Municipal Education Commission(Grant Nos.KZ202210005006 and KZ202110005007).
文摘The hemodynamics of intracranial aneurysm(IA)comprises complex transient flow patterns that affect its growth and rupture.Owing to the combined effects of geometrical factors and pulsatile flow conditions,the transient flow patterns in the IA are still unclear.The purpose of this work is to reveal the effect of the aspect ratio(AR,sac height/neck width)on the evolution of the internal flow patterns and the hemodynamics of the IA.We proposed an easy method to fabricate three simplified elastic IA models and measured the transient flow characteristics by using particle image velocimetry(PIV).Transient vortex structures in the IA modes during a cardiac cycle were systemically measured and many new flow phenomena were found,including the vortex morphology(size,structure,and core location),a high-speed jet,wall compliance effects,and three flow modes during retrograde flow phase.The results show that the AR of the IA affects the transient flow patterns as well as the wall shear stress(WSS)in complex ways.The results could deepen our understanding of the transient flow behaviors in IA and guide related clinical studies.
