The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 sub-member in the Ordos Basin were systematically investigated t...The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 sub-member in the Ordos Basin were systematically investigated to reveal the main controlling factors of shale oil occurrence under different lamina combinations.The differential enrichment mechanisms and patterns of shale oil were discussed using the shale oil micro-migration characterization and evaluation methods from the perspectives of relay hydrocarbon supply,stepwise migration,and multi-stage differentiation.The results are obtained in five aspects.First,Chang 73 shale mainly develops five types of lamina combination,i.e.non-laminated shale,sandy laminated shale,tuffaceous laminated shale,mixed laminated shale,and organic-rich laminated shale.Second,shales with different lamina combinations are obviously different in the reservoir space.Specifically,shales with sandy laminae and tuffaceous laminae have a large number of intergranular pores,dissolution pores and hydrocarbon generation-induced fractures.The multi-scale pore and fracture system constitutes the main place for liquid hydrocarbon occurrence.Third,the occurrence and distribution of shale oil in shale with different lamina combinations are jointly controlled by organic matter abundance,reservoir property,thermal evolution degree,mineral composition and laminae scale.The micro-nano-scale pore-fracture networks within shales containing rigid laminae,particularly sandy and tuffaceous laminations,primarily contain free-state light hydrocarbon components.In contrast,adsorption-phase heavy hydrocarbon components predominantly occupy surfaces of organic matter assemblages,clay mineral matrices,and framework mineral particulates.Fourth,there is obvious shale oil micro-migration between shales with different lamina combinations in Chang 73.Generally,such micro-migration is stepwise in a sequence of organic-rich laminated shale→tuffaceous laminated shale→mixed laminated shale→sandy lamiated shale→non-laminated shale.Fifth,the relay hydrocarbon supply of organic matter under the control of the spatial superposition of shales with various laminae,the stepwise migration via multi-scale pore and fracture network,and the multi-differentiation in shales with different lamina combinations under the control of organic-inorganic interactions fundamentally decide the differences of shale oil components between shales with different lamina combinations.展开更多
In recent years the crucial role of CD4^(+)T cells in tumor immunomodulation has garnered increasing recognition.While conventional cancer immunotherapy research has predominantly focused on the cytotoxic function of ...In recent years the crucial role of CD4^(+)T cells in tumor immunomodulation has garnered increasing recognition.While conventional cancer immunotherapy research has predominantly focused on the cytotoxic function of CD8+T cells,emerging evidence has now shown that CD4^(+)T cells enhance antitumor immunity by delivering co-stimulatory signals,secreting cytokines,and promoting cytotoxic T lymphocyte(CTL)activation and display unique immunoregulatory capabilities through direct tumor cell killing or remodeling of the tumor microenvironment.The high heterogeneity and functional plasticity of CD4^(+)T cell subsets significantly influence clinical responses to immunotherapy with underlying mechanisms involving multi-level regulatory networks,including epigenetic modulation and metabolic reprogramming.Deciphering the functional heterogeneity of CD4^(+)T cells and the interactions with the tumor microenvironment will provide essential mechanistic insights for next-generation immunotherapies,such as immune checkpoint inhibitors and chimeric antigen receptor T(CAR-T)therapies,thereby advancing personalized treatment paradigms.展开更多
The present work focused on developing an innovative composite material by reinforcing polymer matrix with highly porous activated charcoal. Polyvinyl alcohol-activated charcoal（PVA-AC） composite scaffolds were deve...The present work focused on developing an innovative composite material by reinforcing polymer matrix with highly porous activated charcoal. Polyvinyl alcohol-activated charcoal（PVA-AC） composite scaffolds were developed by varying the AC concentrations（0, 0.5, 1, 1.5, 2 and 2.5 wt%） in PVA matrix by freeze drying method. The developed scaffolds were characterized for their physicochemical, mechanical and in-vitro biological properties. In addition, the effect of AC on the attachment, proliferation and differentiation of osteoblast MG 63 cells was evaluated by scanning electron microscopy（SEM）, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide（MTT） assay, alkaline phosphatase（ALP） activity assay and alizarin red stain-based（ARS） assay. All the PVA-AC composite scaffolds exhibited good bioactivity, hemocompatibility and protein adsorption properties. The scaffolds with high AC concentration（2.5 wt%） showed controlled drug release kinetics that are suitable for long term healing. The mechanical properties of all the PVA-AC composite scaffolds were improved when compared to the pure PVA scaffold. The high porosity, swelling degree and hydrophilicity of PVA-AC composite scaffolds facilitated cell attachment and proliferation. This is due to porous AC present in the sample that supported the osteoblast differentiation and formed mineralized nodules without the addition of any extra agents. From the above studies, it can be concluded that PVA-AC composite scaffolds are promising biomaterials for bone tissue engineering applications.展开更多
In the present study, we used a proteomics approach based on a two-dimensional electrophoresis （2-DE） reference map to investigate protein expression in the ovarian tissues of pubertal Swiss-Webster mice subjected t...In the present study, we used a proteomics approach based on a two-dimensional electrophoresis （2-DE） reference map to investigate protein expression in the ovarian tissues of pubertal Swiss-Webster mice subjected to carbon ion radiation （CIR）. Among the identified proteins, ubiquitin carboxy-terminal hydrolase L1 （UCH-L1） is associated with the cell cycle[1] and that it influences proliferation in ovarian tissues. We analyzed the expression of UCH-L1 and the proliferation marker proliferation cell nuclear antigen （PCNA） following CIR using immunoblotting and immunofluorescence. The proteomics and biochemical results provide insight into the underlying mechanisms of CIR toxicity in ovarian tissues.展开更多
COBOT is a new kind of collaborative robot , which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based t...COBOT is a new kind of collaborative robot , which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based the feature of nonhlonnmic constraint. The dynamic model of differential mechanism and five-bar architecture COBOT is founded. There are two kinds of coupled mode of two CVT:serial and parallel. In this paper, we present the dynamic model of serial and parallel COBOT take five-bar COBOT as research object. From the dynamic analysis foregoing, both serial and parallel COBOT model are have the feature of nonholonomic constraint. The ending track and moving state are controlled by the force of control motor and operator. The control motor can not control the movement and ending track of COBOT without the cooperation of operator.展开更多
In bone tissue engineering microstructure design,adjusting the structural design of biomimetic bone scaffolds can provide distinct differentiation stimuli to cells on the scaffold surface.This study explored the biome...In bone tissue engineering microstructure design,adjusting the structural design of biomimetic bone scaffolds can provide distinct differentiation stimuli to cells on the scaffold surface.This study explored the biomechanical impacts of different biomimetic microstructures on advanced bone tissue engineering scaffolds.Two irregular bone scaffolds(homogeneous/radial gradient)based on the Voronoi tesselation algorithm and eight regular lattice scaffolds involving pillar body centered cubic,vintiles,diamond,and cube(homogeneous/radial gradient)with constant 80%porosity were constructed.Mechanical stimulation differentiation algorithms,finite element analysis,and computational fluid dynamics were used to investigate the effects of different pore structures on the octahedral shear strain and fluid flow shear stress within the scaffolds,thereby elucidating the differentiation capabilities of the five structural bone/cartilage cell types.The findings demonstrated that irregular structures and radial-gradient designs promoted osteogenic differentiation,whereas regular structures and homogeneous designs facilitated chondrogenic differentiation.The highest percentages of osteoblast and chondrocyte differentiation were observed in radial-gradient irregular scaffolds.This research provides insights into the microstructure design of bone tissue engineering implants.展开更多
Mechanism functions and kinetic parameters of AlOOH（boehmite or diaspore） dissolving in sodium hydroxide solution were researched.The mixture of boehmite or diaspore and caustic solution was scanned by high-pressure...Mechanism functions and kinetic parameters of AlOOH（boehmite or diaspore） dissolving in sodium hydroxide solution were researched.The mixture of boehmite or diaspore and caustic solution was scanned by high-pressure differential scanning calorimetry（DSC） instrument with heating rate of 10 ℃/min,and differential equation method was used to analyse the DSC curves,combining with iterative method and linear least square method.The most probable mechanism functions for both boehmite or diaspore and caustic solution reactions were logically selected from 30 types of non-isothermal kinetics differential equations,according to the calculated results obtained by Matlab program.The most probable differential mechanism function of boehmite dissolving in caustic solution is f（α）=1-α,which reveals the first-order reaction with apparent activation energy of 79.178 kJ/mol and the preexponential constant 1.031×108 s-1.The function,f（α）=2（1-α）3/2,can describe the dissolution of diaspore sample in sodium hydroxide solution.The calculated results of kinetic parameters are apparent activation energy of 73.858 kJ/mol,preexponential constant of 5.752×107 s-1 and reaction order of 1.5.展开更多
Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to i...Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to ideal solution, geospatial analysis, and optimal parameter geodetector, this study investigates the patterns and mechanisms of China's TONED in the prefecture-level cities from 2011 to 2020. The findings reveal that(1) the TONED exhibited a spatial distribution characterized by higher levels in the east and lower levels in the west, along with a pyramidal hierarchy of levels. The distribution of hot and cold spots roughly followed the Heihe-Yulin line.(2) The informatization levels, openness to the outside world, and urbanization played a dominant role in the TONED. The types of dual-factor interactions exhibited both dual-factor enhancement and non-linear enhancement effects.(3) The eastern and central regions were more likely to promote the TONED through enhanced informatization levels, whereas the western region relied more on increasing openness. This study finds that the TONED results from the combined effects of three geographical natures, each playing a distinct role. The recommendations provided can serve as a reference for China and other developing countries to implement the TONED in the context of deglobalization.展开更多
In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed...In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmission ratio etc. are investigated in detail for each unit. Following this, several examples of using a noncircular gear pair in the units and their manipulation technique are introduced.展开更多
Embryonic stem (ES) cell biology is attracting much attention in cell biology because of their pluripotent behaviors and potential therapeutic applications. However,what maintains ES cell pluripotency and what trigger...Embryonic stem (ES) cell biology is attracting much attention in cell biology because of their pluripotent behaviors and potential therapeutic applications. However,what maintains ES cell pluripotency and what triggers ES cell展开更多
A screw drive in-pipe robot is promising inspection equipment for small pipes. However, most of the existing screw drive in-pipe robots have problems of motion interference and slipping inside curved or irregular pipe...A screw drive in-pipe robot is promising inspection equipment for small pipes. However, most of the existing screw drive in-pipe robots have problems of motion interference and slipping inside curved or irregular pipes. These problems result from the coupled relations among the steering motion, the motion speed and the load ability of the robot. In order to deal with the problems, the axiomatic design （AD） theory is applied to evaluate and analyze the existing designs. Then an uncoupled con- cept design based on the AD theory is proposed and the complete AD decomposition process is presented. After that, the pro- posed robot based on a tri-axial differential angle modulation mechanism is designed to realize the uncoupled concept. Finally, the uncoupled property is verified in a dynamics simulation system. The simulation results indicate that the mc tion speed, load ability and steering motion of the proposed robot can be adjusted individually compared with the robots taat have inclin- ing-angle-fixed rollers. Owing to the uncoupled design, the proposed robot can mechanically adapt to straight pipes and curved pipes with less roller slipping.展开更多
基金Supported by the National Natural Science Foundation of China(42302184)Innovation Group Project of Basic Research in Gansu Province,China(22JR5RA045)。
文摘The lamina(combination)types,reservoir characteristics and shale oil occurrence states of organic-rich shale in the Triassic Yanchang Formation Chang 73 sub-member in the Ordos Basin were systematically investigated to reveal the main controlling factors of shale oil occurrence under different lamina combinations.The differential enrichment mechanisms and patterns of shale oil were discussed using the shale oil micro-migration characterization and evaluation methods from the perspectives of relay hydrocarbon supply,stepwise migration,and multi-stage differentiation.The results are obtained in five aspects.First,Chang 73 shale mainly develops five types of lamina combination,i.e.non-laminated shale,sandy laminated shale,tuffaceous laminated shale,mixed laminated shale,and organic-rich laminated shale.Second,shales with different lamina combinations are obviously different in the reservoir space.Specifically,shales with sandy laminae and tuffaceous laminae have a large number of intergranular pores,dissolution pores and hydrocarbon generation-induced fractures.The multi-scale pore and fracture system constitutes the main place for liquid hydrocarbon occurrence.Third,the occurrence and distribution of shale oil in shale with different lamina combinations are jointly controlled by organic matter abundance,reservoir property,thermal evolution degree,mineral composition and laminae scale.The micro-nano-scale pore-fracture networks within shales containing rigid laminae,particularly sandy and tuffaceous laminations,primarily contain free-state light hydrocarbon components.In contrast,adsorption-phase heavy hydrocarbon components predominantly occupy surfaces of organic matter assemblages,clay mineral matrices,and framework mineral particulates.Fourth,there is obvious shale oil micro-migration between shales with different lamina combinations in Chang 73.Generally,such micro-migration is stepwise in a sequence of organic-rich laminated shale→tuffaceous laminated shale→mixed laminated shale→sandy lamiated shale→non-laminated shale.Fifth,the relay hydrocarbon supply of organic matter under the control of the spatial superposition of shales with various laminae,the stepwise migration via multi-scale pore and fracture network,and the multi-differentiation in shales with different lamina combinations under the control of organic-inorganic interactions fundamentally decide the differences of shale oil components between shales with different lamina combinations.
基金supported by The National Key Research and Development Program of China(Grant No.2021YFA0910100)Healthy Zhejiang One Million People Cohort(Grant No.K-20230085)+6 种基金supported by National Natural Science Foundation of China(Grant Nos.82304946 and 82573745)Post-doctoral Innovative Talent Support Program(Grant No.BX2023375)567 Foundation of Zhejiang Province(Grant No.LMS25H160006)supported by the National Natural Science Foundation of China(Grant No.82473489)the Medical Science and Technology Project of Zhejiang Province(Grant No.WKJ-ZJ-2202)the Natural Science Foundation of Zhejiang Province(Grant No.LBD24H290001)supported by the National Natural Science Foundation of China(Grant No.82403546).
文摘In recent years the crucial role of CD4^(+)T cells in tumor immunomodulation has garnered increasing recognition.While conventional cancer immunotherapy research has predominantly focused on the cytotoxic function of CD8+T cells,emerging evidence has now shown that CD4^(+)T cells enhance antitumor immunity by delivering co-stimulatory signals,secreting cytokines,and promoting cytotoxic T lymphocyte(CTL)activation and display unique immunoregulatory capabilities through direct tumor cell killing or remodeling of the tumor microenvironment.The high heterogeneity and functional plasticity of CD4^(+)T cell subsets significantly influence clinical responses to immunotherapy with underlying mechanisms involving multi-level regulatory networks,including epigenetic modulation and metabolic reprogramming.Deciphering the functional heterogeneity of CD4^(+)T cells and the interactions with the tumor microenvironment will provide essential mechanistic insights for next-generation immunotherapies,such as immune checkpoint inhibitors and chimeric antigen receptor T(CAR-T)therapies,thereby advancing personalized treatment paradigms.
基金the Department of Biotechnology and Medical Engineering, The National Institute of Technology
文摘The present work focused on developing an innovative composite material by reinforcing polymer matrix with highly porous activated charcoal. Polyvinyl alcohol-activated charcoal（PVA-AC） composite scaffolds were developed by varying the AC concentrations（0, 0.5, 1, 1.5, 2 and 2.5 wt%） in PVA matrix by freeze drying method. The developed scaffolds were characterized for their physicochemical, mechanical and in-vitro biological properties. In addition, the effect of AC on the attachment, proliferation and differentiation of osteoblast MG 63 cells was evaluated by scanning electron microscopy（SEM）, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide（MTT） assay, alkaline phosphatase（ALP） activity assay and alizarin red stain-based（ARS） assay. All the PVA-AC composite scaffolds exhibited good bioactivity, hemocompatibility and protein adsorption properties. The scaffolds with high AC concentration（2.5 wt%） showed controlled drug release kinetics that are suitable for long term healing. The mechanical properties of all the PVA-AC composite scaffolds were improved when compared to the pure PVA scaffold. The high porosity, swelling degree and hydrophilicity of PVA-AC composite scaffolds facilitated cell attachment and proliferation. This is due to porous AC present in the sample that supported the osteoblast differentiation and formed mineralized nodules without the addition of any extra agents. From the above studies, it can be concluded that PVA-AC composite scaffolds are promising biomaterials for bone tissue engineering applications.
基金supported by the Fostering Foundation for the Excellent Ph D.Dissertation of Gansu Agricultural University(2013002)the National High Technology Research and Development Program of China(2013AA102505)the Ministry of Science and Technology National Key R&D project(2016YFC0904600)
文摘In the present study, we used a proteomics approach based on a two-dimensional electrophoresis （2-DE） reference map to investigate protein expression in the ovarian tissues of pubertal Swiss-Webster mice subjected to carbon ion radiation （CIR）. Among the identified proteins, ubiquitin carboxy-terminal hydrolase L1 （UCH-L1） is associated with the cell cycle[1] and that it influences proliferation in ovarian tissues. We analyzed the expression of UCH-L1 and the proliferation marker proliferation cell nuclear antigen （PCNA） following CIR using immunoblotting and immunofluorescence. The proteomics and biochemical results provide insight into the underlying mechanisms of CIR toxicity in ovarian tissues.
基金the National Natural Science Foundation of China( 60275030) Harbin Science and Technology Bureau(2002AFLXJ004)
文摘COBOT is a new kind of collaborative robot , which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based the feature of nonhlonnmic constraint. The dynamic model of differential mechanism and five-bar architecture COBOT is founded. There are two kinds of coupled mode of two CVT:serial and parallel. In this paper, we present the dynamic model of serial and parallel COBOT take five-bar COBOT as research object. From the dynamic analysis foregoing, both serial and parallel COBOT model are have the feature of nonholonomic constraint. The ending track and moving state are controlled by the force of control motor and operator. The control motor can not control the movement and ending track of COBOT without the cooperation of operator.
基金the National Natural Science Foundation of China(No.52165026)。
文摘In bone tissue engineering microstructure design,adjusting the structural design of biomimetic bone scaffolds can provide distinct differentiation stimuli to cells on the scaffold surface.This study explored the biomechanical impacts of different biomimetic microstructures on advanced bone tissue engineering scaffolds.Two irregular bone scaffolds(homogeneous/radial gradient)based on the Voronoi tesselation algorithm and eight regular lattice scaffolds involving pillar body centered cubic,vintiles,diamond,and cube(homogeneous/radial gradient)with constant 80%porosity were constructed.Mechanical stimulation differentiation algorithms,finite element analysis,and computational fluid dynamics were used to investigate the effects of different pore structures on the octahedral shear strain and fluid flow shear stress within the scaffolds,thereby elucidating the differentiation capabilities of the five structural bone/cartilage cell types.The findings demonstrated that irregular structures and radial-gradient designs promoted osteogenic differentiation,whereas regular structures and homogeneous designs facilitated chondrogenic differentiation.The highest percentages of osteoblast and chondrocyte differentiation were observed in radial-gradient irregular scaffolds.This research provides insights into the microstructure design of bone tissue engineering implants.
基金Project(2007BC13504)supported by the National Basic Research Program of ChinaProject(20050145029)supported by Research Fund for the Doctoral Program of Higher EducationProject(2005221012)supported by the Science and Technology Talents Fund for Excellent Youth of Liaoning Province,China
文摘Mechanism functions and kinetic parameters of AlOOH（boehmite or diaspore） dissolving in sodium hydroxide solution were researched.The mixture of boehmite or diaspore and caustic solution was scanned by high-pressure differential scanning calorimetry（DSC） instrument with heating rate of 10 ℃/min,and differential equation method was used to analyse the DSC curves,combining with iterative method and linear least square method.The most probable mechanism functions for both boehmite or diaspore and caustic solution reactions were logically selected from 30 types of non-isothermal kinetics differential equations,according to the calculated results obtained by Matlab program.The most probable differential mechanism function of boehmite dissolving in caustic solution is f（α）=1-α,which reveals the first-order reaction with apparent activation energy of 79.178 kJ/mol and the preexponential constant 1.031×108 s-1.The function,f（α）=2（1-α）3/2,can describe the dissolution of diaspore sample in sodium hydroxide solution.The calculated results of kinetic parameters are apparent activation energy of 73.858 kJ/mol,preexponential constant of 5.752×107 s-1 and reaction order of 1.5.
基金National Natural Science Foundation of China,No.42371188National Social Science Foundation of China,No.20BJL104+2 种基金Major Project of Key Research Bases of Humanities and Social Sciences,Ministry of Education,No.22JJD790016Major Project of Applied Research in Philosophy and Social Sciences at Colleges and Universities in Henan Province,No.2023-YYZD-03Program of Excellence for Graduate Students of Henan University,No.SYLYC2023123。
文摘Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to ideal solution, geospatial analysis, and optimal parameter geodetector, this study investigates the patterns and mechanisms of China's TONED in the prefecture-level cities from 2011 to 2020. The findings reveal that(1) the TONED exhibited a spatial distribution characterized by higher levels in the east and lower levels in the west, along with a pyramidal hierarchy of levels. The distribution of hot and cold spots roughly followed the Heihe-Yulin line.(2) The informatization levels, openness to the outside world, and urbanization played a dominant role in the TONED. The types of dual-factor interactions exhibited both dual-factor enhancement and non-linear enhancement effects.(3) The eastern and central regions were more likely to promote the TONED through enhanced informatization levels, whereas the western region relied more on increasing openness. This study finds that the TONED results from the combined effects of three geographical natures, each playing a distinct role. The recommendations provided can serve as a reference for China and other developing countries to implement the TONED in the context of deglobalization.
文摘In view of the lack of systemic analysis for stepless transmission using noncircular gears, two basic noncircular gear units, an addition unit adopting differential mechanism and a multiplication unit applying a fixed gear train, are proposed. Then, the design methods of the noncircular gear pair of each unit, transmission ratio relationship, rotation angle relationship and key parameters with specific physical meanings are studied. The adjusting properties, composing strategy and varying range of transmission ratio etc. are investigated in detail for each unit. Following this, several examples of using a noncircular gear pair in the units and their manipulation technique are introduced.
文摘Embryonic stem (ES) cell biology is attracting much attention in cell biology because of their pluripotent behaviors and potential therapeutic applications. However,what maintains ES cell pluripotency and what triggers ES cell
基金supported by the National Natural Science Foundation of China(Grant No.61273345)
文摘A screw drive in-pipe robot is promising inspection equipment for small pipes. However, most of the existing screw drive in-pipe robots have problems of motion interference and slipping inside curved or irregular pipes. These problems result from the coupled relations among the steering motion, the motion speed and the load ability of the robot. In order to deal with the problems, the axiomatic design （AD） theory is applied to evaluate and analyze the existing designs. Then an uncoupled con- cept design based on the AD theory is proposed and the complete AD decomposition process is presented. After that, the pro- posed robot based on a tri-axial differential angle modulation mechanism is designed to realize the uncoupled concept. Finally, the uncoupled property is verified in a dynamics simulation system. The simulation results indicate that the mc tion speed, load ability and steering motion of the proposed robot can be adjusted individually compared with the robots taat have inclin- ing-angle-fixed rollers. Owing to the uncoupled design, the proposed robot can mechanically adapt to straight pipes and curved pipes with less roller slipping.
