Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi...Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.展开更多
Transportation structures such as composite pavements and railway foundations typically consist of multi-layered media designed to withstand high bearing capacity.A theoretical understanding of load transfer mechanism...Transportation structures such as composite pavements and railway foundations typically consist of multi-layered media designed to withstand high bearing capacity.A theoretical understanding of load transfer mechanisms in these multi-layer composites is essential,as it offers intuitive insights into parametric influences and facilitates enhanced structural performance.This paper employs an improved transfer matrix method to address the limitations of existing theoretical approaches for analyzing multi-layer composite structures.By establishing a twodimensional composite pavement model,it investigates load transfer characteristics and validates the accuracy through finite element simulation.The proposed method offers a straightforward analytical approach for examining internal interactions between structural layers.Case studies indicate that the concrete surface layer is the main load-bearing layer for most vertical normal and shear stresses.The soil base layer reduces the overall mechanical response of the substructure,while horizontal actions increase the risk of interfacial slip and cracking.Structural optimization analysis demonstrates that increasing the thickness of the concrete surface layer,enhancing the thickness and stiffness of the soil base layer,or incorporating gradient layers can significantly mitigate these risks of interfacial slip and cracking.The findings of this study can guide the optimization design,parameter analysis,and damage prevention of multi-layer composite structures.展开更多
[Objective] This study aimed to investigate the effects of PP333 and ex- ogenous ABA on the growth and development of Armeniaca vulgaris ＇Luntaibaixing＇ so as to provide a theoretical basis for the growth regulation...[Objective] This study aimed to investigate the effects of PP333 and ex- ogenous ABA on the growth and development of Armeniaca vulgaris ＇Luntaibaixing＇ so as to provide a theoretical basis for the growth regulation of Luntaibaixing in cultivation and management. [Method} Different concentrations of PP333 and ABA were sprayed to Luntaibaixing during the rapid growth period of fresh treetops. The technology of paraffin section was used to measure the thickness of leaf, upper epidermis, lower epidermis, palisade tissue and sponge tissue. The thickness ratio of palisade tissue to sponge tissue, tightness degree of leaf tissue structure （CTR） and loose degree of leaf tissue structure （SR） were calculated and the differences in leaf tissue structure were analyzed. [Result] The thickness of leaf and palisade tissue both increased significantly after treated by PP333. At the treatment concen- tration of 1 000 mg/L, the thickness ratio of palisade tissue to sponge tissue and the value of CTR were highest, while the thickness of sponge tissue and the value of SR were lowest. The thickness of leaf and palisade tissue also increased after treated by ABA, and it increased most greatly at the ABA concentration of 60 mg/L compared with CK. At the treatment concentration of 60 rag/L, the thickness ratio of palisade tissue to sponge tissue and the value of CTR were the highest, while the thickness of sponge tissue and the value of SR were the lowest. [Conclusion] ABA and PP333 treatment increased the leaf thickness, palisade tissue thickness, pal- isade tissue to sponge tissue thickness ratio and CRT value, but reduced the sponge tissue thickness and SR value of Luntaibaixing.展开更多
[Objective] The research aimed to provide theoretical basis for the cultivation and production of peach.[Method] The three-year-old seedling peach tree was used as the materials,and NH4NO3 was used as the experimental...[Objective] The research aimed to provide theoretical basis for the cultivation and production of peach.[Method] The three-year-old seedling peach tree was used as the materials,and NH4NO3 was used as the experimental nitrogen fertilizer.Three nitrogen levels,0,3,6 g per pot respectively were set to study the effects of different nitrogen fertilizer on the contents of soluble sugar,starch and internal structure of the root of the peaches.[Result] The contents of soluble sugar of roots and leaves increased with the increase of nitrogen fertilizer level,and the level of 6 g per pot was the highest,which showed extreme differences between the level of 3 g per pot and the control.However,starch contents showed opposite results,which decreased as the level of nitrogen fertilizer increased.Compared with the 3 g per pot level of nitrogen fertilizer and the control,the internal structure of root applied with nitrogen fertilizer of 6 g per pot level had larger fibrovascularcylinder,advanced vascular bundle,small-spaced thin-walled cells,smooth and full cells with smooth cell wall.[Conclusion]Appropriate nitrogen levels can accelerate the accumulation of soluble sugar and the growth of root tissue structure.展开更多
The electrospinning process was applied to fabricate the nanofibers of biodegradable poly(ε-caprolactone)(PCL) in which different contents of multiwalled carbon nanotubes(MWCNTs) were embedded. Afterward,the electros...The electrospinning process was applied to fabricate the nanofibers of biodegradable poly(ε-caprolactone)(PCL) in which different contents of multiwalled carbon nanotubes(MWCNTs) were embedded. Afterward,the electrospun nanofibers were successfully decorated with shish-kebab structure via a self-induced crystallization technique. The topographical features and the mechanical properties of the composite scaffolds were characterized,and the biocompatibility of the material was assessed by using human osteogenic sarcoma osteoblasts(MG-63 cells). The carbon nanotube(CNT) concentration is found to affect the fiber diameter and mechanical properties of electrospun nanofibers and the periodic distance of the shish-kebab architecture. Cellular attachment and proliferation assays reveal that 0.5 wt% CNT-embedded PCL scaffold shows enhanced biocompatibility with MG-63 cells than their counterparts made of neat PCL, and the collagen-like nanotopology provided by the shish-kebab structure further facilitates the cell adhesion and proliferation. The superior interactions between cells and scaffolds demonstrate that the shish-kebab-structured CNTs/PCL nanofibers may be promising candidate for tissue engineering scaffold application.展开更多
[Objectives] To study the protective and recovery effects of Yupingfeng polysaccharides( YPF-P) on spleen tissue structure of acute and chronic immunocompromised mice. [Methods]First,90 mice in the protective group we...[Objectives] To study the protective and recovery effects of Yupingfeng polysaccharides( YPF-P) on spleen tissue structure of acute and chronic immunocompromised mice. [Methods]First,90 mice in the protective group were injected with cyclophosphamide to replicate the chronic immunosuppressive model,and observe the protective effects of different doses of YPF-P on the spleen; 120 mice in the recovery group were injected with cyclophosphamide continuously to replicate the acute immune injury model,to observe the effects of YPF-P on spleen recovery. Besides,YPF-P positive control group was established to observe its effects on the spleen structure and function of normal mice. Testing indicators include spleen morphology and tissue structure,body mass,and spleen index. [Results]In the protective group and the recovery group,the spleen volume of the mice with different YPF-P doses increased significantly,and lymphocytes proliferated,showing obvious structural compensation and repair,and showing a dose-effect relationship. In the positive control group,the spleen function of the normal mice was significantly enhanced,and the spleen lymphoid tissue showed significant orderly proliferation. [Conclusions]Yupingfeng polysaccharides can effectively protect the function and structure of spleen,improve acute and chronic immune damage induced by cyclophosphamide,greatly promote the recovery of spleen structure and function after immune injury,and also can significant enhance the spleen structure and function of normal mice.展开更多
[Objective] This study was performed to explore the effect of different concentrations of PP333 on leaf tissue structure of Korla fragrant pear and to lay the foundation for the cultivation and regulation of Korla fra...[Objective] This study was performed to explore the effect of different concentrations of PP333 on leaf tissue structure of Korla fragrant pear and to lay the foundation for the cultivation and regulation of Korla fragrant pear. [Method] The leaf tissues treated with different concentrations of PP333 were dehydrated with al- cohol, embedded in paraffin and sliced into 10-μm slices. The thicknesses of leaf blade, upper epidermis, lower epidermis, palisade tissue and sponge tissue were measured, and the ratio of palisade to spongy layer thickness, cell tightness （CT） and cell looseness （CL） were calculated. [Result] The thickness of leaf blade, the ratio of palisade to sponge layer thickness and the thickness of palisade layer were all significantly increased after treatment with PP333. Treatment with 2 500 mg/L PP333 showed no obvious effect on the thickness of leaf epidermis, but increased the thicknesses of leaf blade and palisade tissue. Leaf CL was the highest in the treatment of 1 500 mg/L PP333. [Conclusion] PP333 can increase the leaf thickness, palisade tissue thickness and CT, reduce spongy tissue thickness and CL of Korla fragrant pear. Additionally, 1 500 mg/L was the optimal concentration for the application of PP333 to improve the cold resistance of Koda fragrant pear.展开更多
Structured illumination microscopy(SIM)is an established optical superresolution imaging technique.However,conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular sampl...Structured illumination microscopy(SIM)is an established optical superresolution imaging technique.However,conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular samples.We propose combining one-dimensional image rescan and structured illumination in the orthogonal direction to achieve superresolution without the need to rotate the illumination pattern.The image acquisition speed is consequently improved threefold,which is also beneficial for minimizing photobleaching and phototoxicity.Optical sectioning in thick biological tissue is enhanced by including a confocal slit in the system to significantly suppress the out-of-focus background and the associated noise.With all the technical improvements,our method captures threedimensional superresolved image stacks of neuronal structures in mouse brain tissue samples for a depth range of more than 200μm.展开更多
A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macr...A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macro channels＇ shape, size and distribution. By integrating rapid prototyping and traditional porogen technique, the macro channels and micro pores were formed respectively. The size, shape and quantity of micro pores were controlled by porogen particulates. The sintered β-TCP porous scaffolds possessed connective macro channels of approximately 500 μm and micro pores of 200-400 μm. The porosity and connectivity of micro pores became higher with the increase of porogen ratio, while the mechanical properties weakened. The average porosity and compressive strength offl-TCP scaffolds prepared with porogen ratio of 60wt% were 78.12% and 0.2983 MPa, respectively. The cells＇ adhesion ratio of scaffolds was 67.43%. The ALP activity, OCN content and cells micro morphology indicated that cells grew and proliferated well on the scaffolds.展开更多
To study the effects of different concentrations of Abscisic Acid(ABA) on leaf tissue structure of Korla fragrant pear and lay the foundation for the cultivation and regulation of Korla fragrant pear. Using the paraff...To study the effects of different concentrations of Abscisic Acid(ABA) on leaf tissue structure of Korla fragrant pear and lay the foundation for the cultivation and regulation of Korla fragrant pear. Using the paraffin section method, the leaf thickness, the epidermis thickness, the palisade tissue thickness and the sponge tissue thickness were measured; palisade spongy ratio, Cell Tightness(CT) and Cell Looseness(CL) were examined after treatments with exogenous ABA. Leaf thickness, leaf palisade spongy ratio and palisade tissue thickness increased significantly after exogenous ABA treatment compared with CK, while the effect on leaf epidermis was not obvious. The leaf thickness and palisade tissue thickness increased evidently after 70 mg · LABA treatment by 24.89% and 41.10%, respectively. The tissue structures of leaves were more compact, while CL was lower after 70 and 90 mg · LABA treatments. The effects of different concentrations of exogenous ABA could increase the leaf thickness, palisade tissue thickness of Korla fragrant pear and CT, reduced the thickness of spongy tissue and CL. Among those concentrations of exogenous ABA, the effect of spraying 70 mg · Lexogenous ABA was suitable for improving cold resistance of Korla fragrant pear.展开更多
In order to improve the operability and accuracy of high-intensity focused ultrasound （HIFU）, an annular focused transducer, whereby a B-ultrasound probe is placed in its center, is used to realize the real time mon...In order to improve the operability and accuracy of high-intensity focused ultrasound （HIFU）, an annular focused transducer, whereby a B-ultrasound probe is placed in its center, is used to realize the real time monitoring and control of the treatment. In this paper, the spheroidal beam equation （SBE） was used to calculate the sound lield by an annular focused transducer with a wide aperture angle to first derive the heat deposition and the Pennes equation was used to calculate the temperature field in multi-layer tissue. We studied the effect of different parameters on the temperature of the tissues. The result shows that the focal length has a significant influence on both maximum liver temperature rise and skin temperature rise, and both increase with the increase in the focal length. When the frequency increases, the temperature rise first undergoes a rapid increase before gradually reaching a maximum, and then finally decreasing. The temperature rise increases while the inner radius decreases or the sound pressure increases. By choosing suitable parameters, the proper temperature rise both on the target tissue and skin via an annular tbcused transducer with a wide aperture angle can be obtained.展开更多
The organized alignment of cells in various tissues plays a significant role in the maintenance of specific functions.To induce such an alignment,ideal scaffolds should simulate the characteristics and morphologies of...The organized alignment of cells in various tissues plays a significant role in the maintenance of specific functions.To induce such an alignment,ideal scaffolds should simulate the characteristics and morphologies of natural tissues.Aligned structures that guide cell orientation are used to facilitate tissue regeneration and repair.We here review how various aligned structures are fabricated,including aligned electrospun nanofibers,aligned porous or channeled structures,micropatterns and combinations thereof,and their application in nerve,skeletal muscle,tendon,and tubular dentin regeneration.The future use of aligned structures in tissue engineering is also discussed.展开更多
A two-dimensional electromagnetic particle-in-cell simulation model is proposed to study the density evolution and collective stopping of electron beams in background plasmas.We show here the formation of the multi-la...A two-dimensional electromagnetic particle-in-cell simulation model is proposed to study the density evolution and collective stopping of electron beams in background plasmas.We show here the formation of the multi-layer structure of the relativistic electron beam in the plasma due to the different betatron frequency from the beam front to the beam tail.Meanwhile,the nonuniformity of the longitudinal wakefield is the essential reason for the multi-layer structure formation in beam phase space.The influences of beam parameters(beam radius and transverse density profile)on the formation of the multi-layer structure and collective stopping in background plasmas are also considered.展开更多
[Objectives] To study the underground stem tissue structure and agronomic traits of different populations of wild Houttuynia cordata Thumb. [Methods] 8 different populations of wild Houttuynia cordata Thumb. in southe...[Objectives] To study the underground stem tissue structure and agronomic traits of different populations of wild Houttuynia cordata Thumb. [Methods] 8 different populations of wild Houttuynia cordata Thumb. in southern China were selected,the preliminary study was carried out about underground stem tissue structure( stem wall thickness,underground stem cross section diameter,medullary cavity,large vascular bundle area,small vascular bundle area,and number of vascular bundles),and main agronomic traits of aboveground and underground parts. [Results]There were significant differences in the underground stem tissue structure and agronomic traits of some populations of wild Houttuynia cordata Thumb. [Conclusions] From comparison,it reached the conclusion that the populations of wild Houttuynia cordata Thumb. in Kunming of Yunnan,Hechuan of Chongqing,and Nanning of Guangxi showed better underground stem tissue structure and agronomic traits. The results are expected to provide certain guidance for cultivation,reasonable development,and utilization of wild populations of Houttuynia cordata Thumb.展开更多
With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the...With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.展开更多
This study proposes a general imperfect thermal contact model to predict the thermal contact resistance at the interface among multi-layered composite structures.Based on the Green-Lindsay(GL)thermoelastic theory,semi...This study proposes a general imperfect thermal contact model to predict the thermal contact resistance at the interface among multi-layered composite structures.Based on the Green-Lindsay(GL)thermoelastic theory,semi analytical solutions of temperature increment and displacement of multi-layered composite structures are obtained by using the Laplace transform method,upon which the effects of thermal resistance coefficient,partition coefficient,thermal conductivity ratio and heat capacity ratio on the responses are studied.The results show that the generalized imperfect thermal contact model can realistically describe the imperfect thermal contact problem.Accordingly,it may degenerate into other thermal contact models by adjusting the thermal resistance coefficient and partition coefficient.展开更多
In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through top...In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.展开更多
In this study,a high impact resistant multi-layered composite consisting of continuous carbon fibre/nylon(CCF)and short carbon fibre/nylon(SCF)layers is developed via 3D printing technology.The effect of CCF/SCF layer...In this study,a high impact resistant multi-layered composite consisting of continuous carbon fibre/nylon(CCF)and short carbon fibre/nylon(SCF)layers is developed via 3D printing technology.The effect of CCF/SCF layers configuration on the impact resistance is investigated by low-velocity impact test,and the impact failure mechanism of the 3D printed composites is explored by microscopic observations and finite element(FE)simulation analysis.The results show that the 3D printed multi-layered composite with SCF layers distributed in the middle(HFA)exhibits higher impact resistant performance than the specimens with alternating SCF/CCF layers(HFB)and CCF layers distributed in the middle(HFC).The effect of CCF/SCF layers proportion on the impact performance is also studied by FE simulation,and the results show that the specimen with a CCF/SCF proportion of 7.0 exhibits the highest impact strength.展开更多
Gold nanoparticles(GNPs) are emerging as a novel tool to improve existing cancer therapeutics. GNPs are being used as radiation dose enhancers in radiation therapy as well as anticancer drugs carriers in chemotherapy....Gold nanoparticles(GNPs) are emerging as a novel tool to improve existing cancer therapeutics. GNPs are being used as radiation dose enhancers in radiation therapy as well as anticancer drugs carriers in chemotherapy. However,the success of GNP-based therapeutics depends on their ability to penetrate tumor tissue. GNPs of 20 and 50 nm diameters were used to elucidate the effects of size on the GNP interaction with tumor cells at monolayer and multilayer level. At monolayer cell level, smaller NPs had a lower uptake compared to larger NPs at monolayer cell level. However, the order was reversed at tissue-like multilayer level. The smaller NPs penetrated better compared to larger NPs in tissue-like materials.Based on our study using tissue-like materials, we can predict that the smaller NPs are better for future therapeutics due to their greater penetration in tumor tissue once leaving the leaky blood vessels. In this study, tissue-like multilayer cellular structures(MLCs) were grown to model the post-vascular tumor environment. The MLCs exhibited a much more extensive extracellular matrix than monolayer cell cultures. The MLC model can be used to optimize the nano–micro interface at tissue level before moving into animal models. This would accelerate the use of NPs in future cancer therapeutics.展开更多
Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided p...Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided process of porous bone modeling was developed which described the design and fabrication of tissue scaffolds by considering intricate architecture,porosity and pore size.To simulate intricate bone structure,different constructive units were presented.In modeling process,bone contour was gotten from computed tomography(CT)images and was divided into two levels.Each level was represented by relatively reconstructive process.Pore size distribution was controlled by using mesh generation.The whole hexahedral mesh was reduced by unit structure,when a 3D mesh with various hexahedral elements was provided.The simulation results show that constructive structure of porous scaffold can meet the needs of clinic implants in accurate and controlled way.展开更多
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(T2121004)Key Programme(52235007)National Outstanding Youth Foundation of China(52325504).
文摘Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.
基金supported by Fundamental Research Funds for the Central Universities(No.lzujbky-2024-05)Innovation Foundation of Provincial Education Department of Gansu(2024B-005)+2 种基金Scientific Department of Gansu(24CXGA083,24CXGA024,JK2024-28,JK2024-32 and 23CXJA0007)Industrial Support Plan Project of Provincial Education Department of Gansu(2025CYZC-003 and CYZC-2024-10)the Hunan Natural Science Foundation Science and Education Joint Fund Project(2022JJ60109).
文摘Transportation structures such as composite pavements and railway foundations typically consist of multi-layered media designed to withstand high bearing capacity.A theoretical understanding of load transfer mechanisms in these multi-layer composites is essential,as it offers intuitive insights into parametric influences and facilitates enhanced structural performance.This paper employs an improved transfer matrix method to address the limitations of existing theoretical approaches for analyzing multi-layer composite structures.By establishing a twodimensional composite pavement model,it investigates load transfer characteristics and validates the accuracy through finite element simulation.The proposed method offers a straightforward analytical approach for examining internal interactions between structural layers.Case studies indicate that the concrete surface layer is the main load-bearing layer for most vertical normal and shear stresses.The soil base layer reduces the overall mechanical response of the substructure,while horizontal actions increase the risk of interfacial slip and cracking.Structural optimization analysis demonstrates that increasing the thickness of the concrete surface layer,enhancing the thickness and stiffness of the soil base layer,or incorporating gradient layers can significantly mitigate these risks of interfacial slip and cracking.The findings of this study can guide the optimization design,parameter analysis,and damage prevention of multi-layer composite structures.
文摘[Objective] This study aimed to investigate the effects of PP333 and ex- ogenous ABA on the growth and development of Armeniaca vulgaris ＇Luntaibaixing＇ so as to provide a theoretical basis for the growth regulation of Luntaibaixing in cultivation and management. [Method} Different concentrations of PP333 and ABA were sprayed to Luntaibaixing during the rapid growth period of fresh treetops. The technology of paraffin section was used to measure the thickness of leaf, upper epidermis, lower epidermis, palisade tissue and sponge tissue. The thickness ratio of palisade tissue to sponge tissue, tightness degree of leaf tissue structure （CTR） and loose degree of leaf tissue structure （SR） were calculated and the differences in leaf tissue structure were analyzed. [Result] The thickness of leaf and palisade tissue both increased significantly after treated by PP333. At the treatment concen- tration of 1 000 mg/L, the thickness ratio of palisade tissue to sponge tissue and the value of CTR were highest, while the thickness of sponge tissue and the value of SR were lowest. The thickness of leaf and palisade tissue also increased after treated by ABA, and it increased most greatly at the ABA concentration of 60 mg/L compared with CK. At the treatment concentration of 60 rag/L, the thickness ratio of palisade tissue to sponge tissue and the value of CTR were the highest, while the thickness of sponge tissue and the value of SR were the lowest. [Conclusion] ABA and PP333 treatment increased the leaf thickness, palisade tissue thickness, pal- isade tissue to sponge tissue thickness ratio and CRT value, but reduced the sponge tissue thickness and SR value of Luntaibaixing.
文摘[Objective] The research aimed to provide theoretical basis for the cultivation and production of peach.[Method] The three-year-old seedling peach tree was used as the materials,and NH4NO3 was used as the experimental nitrogen fertilizer.Three nitrogen levels,0,3,6 g per pot respectively were set to study the effects of different nitrogen fertilizer on the contents of soluble sugar,starch and internal structure of the root of the peaches.[Result] The contents of soluble sugar of roots and leaves increased with the increase of nitrogen fertilizer level,and the level of 6 g per pot was the highest,which showed extreme differences between the level of 3 g per pot and the control.However,starch contents showed opposite results,which decreased as the level of nitrogen fertilizer increased.Compared with the 3 g per pot level of nitrogen fertilizer and the control,the internal structure of root applied with nitrogen fertilizer of 6 g per pot level had larger fibrovascularcylinder,advanced vascular bundle,small-spaced thin-walled cells,smooth and full cells with smooth cell wall.[Conclusion]Appropriate nitrogen levels can accelerate the accumulation of soluble sugar and the growth of root tissue structure.
基金financially supported by the Fundamental Research Funds for the Central Universities (No. 22A201514030)China Postdoctoral Science Foundation (No. 2015M571504)+2 种基金the National Natural Science Foundation of China (Nos. 51503065 and 51273065)the Wisconsin Institute for Discovery in University of Wisconsin-MadisonChina Scholarship Council
文摘The electrospinning process was applied to fabricate the nanofibers of biodegradable poly(ε-caprolactone)(PCL) in which different contents of multiwalled carbon nanotubes(MWCNTs) were embedded. Afterward,the electrospun nanofibers were successfully decorated with shish-kebab structure via a self-induced crystallization technique. The topographical features and the mechanical properties of the composite scaffolds were characterized,and the biocompatibility of the material was assessed by using human osteogenic sarcoma osteoblasts(MG-63 cells). The carbon nanotube(CNT) concentration is found to affect the fiber diameter and mechanical properties of electrospun nanofibers and the periodic distance of the shish-kebab architecture. Cellular attachment and proliferation assays reveal that 0.5 wt% CNT-embedded PCL scaffold shows enhanced biocompatibility with MG-63 cells than their counterparts made of neat PCL, and the collagen-like nanotopology provided by the shish-kebab structure further facilitates the cell adhesion and proliferation. The superior interactions between cells and scaffolds demonstrate that the shish-kebab-structured CNTs/PCL nanofibers may be promising candidate for tissue engineering scaffold application.
基金Supported by Science and Technology Planning Project of Guangdong Province(2016A020210140)Project of Key Laboratory of Preventive Veterinary Medicine for Guangdong Provincial Department of Education(2014KTSPT037)
文摘[Objectives] To study the protective and recovery effects of Yupingfeng polysaccharides( YPF-P) on spleen tissue structure of acute and chronic immunocompromised mice. [Methods]First,90 mice in the protective group were injected with cyclophosphamide to replicate the chronic immunosuppressive model,and observe the protective effects of different doses of YPF-P on the spleen; 120 mice in the recovery group were injected with cyclophosphamide continuously to replicate the acute immune injury model,to observe the effects of YPF-P on spleen recovery. Besides,YPF-P positive control group was established to observe its effects on the spleen structure and function of normal mice. Testing indicators include spleen morphology and tissue structure,body mass,and spleen index. [Results]In the protective group and the recovery group,the spleen volume of the mice with different YPF-P doses increased significantly,and lymphocytes proliferated,showing obvious structural compensation and repair,and showing a dose-effect relationship. In the positive control group,the spleen function of the normal mice was significantly enhanced,and the spleen lymphoid tissue showed significant orderly proliferation. [Conclusions]Yupingfeng polysaccharides can effectively protect the function and structure of spleen,improve acute and chronic immune damage induced by cyclophosphamide,greatly promote the recovery of spleen structure and function after immune injury,and also can significant enhance the spleen structure and function of normal mice.
基金Supported by the Key Technologies Research and Development Program of China during the 12th Five-year Plan(2014BAD16B07)the Fund for Key Discipline of Horticultural Sciences of Xinjiang Uygur Autonomous RegionCentral Financial Forestry Science and Technology Promotion Project(ZYLTKJTG2015017)~~
文摘[Objective] This study was performed to explore the effect of different concentrations of PP333 on leaf tissue structure of Korla fragrant pear and to lay the foundation for the cultivation and regulation of Korla fragrant pear. [Method] The leaf tissues treated with different concentrations of PP333 were dehydrated with al- cohol, embedded in paraffin and sliced into 10-μm slices. The thicknesses of leaf blade, upper epidermis, lower epidermis, palisade tissue and sponge tissue were measured, and the ratio of palisade to spongy layer thickness, cell tightness （CT） and cell looseness （CL） were calculated. [Result] The thickness of leaf blade, the ratio of palisade to sponge layer thickness and the thickness of palisade layer were all significantly increased after treatment with PP333. Treatment with 2 500 mg/L PP333 showed no obvious effect on the thickness of leaf epidermis, but increased the thicknesses of leaf blade and palisade tissue. Leaf CL was the highest in the treatment of 1 500 mg/L PP333. [Conclusion] PP333 can increase the leaf thickness, palisade tissue thickness and CT, reduce spongy tissue thickness and CL of Korla fragrant pear. Additionally, 1 500 mg/L was the optimal concentration for the application of PP333 to improve the cold resistance of Koda fragrant pear.
基金supported by the Ministry of Education-Singapore(Grant Nos.MOE2019-T2-2-094 and MOE Tier I R-397-000-327-114)Shenzhen Science and Technology Program(Grant No.GJHZ20210705141805015).
文摘Structured illumination microscopy(SIM)is an established optical superresolution imaging technique.However,conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular samples.We propose combining one-dimensional image rescan and structured illumination in the orthogonal direction to achieve superresolution without the need to rotate the illumination pattern.The image acquisition speed is consequently improved threefold,which is also beneficial for minimizing photobleaching and phototoxicity.Optical sectioning in thick biological tissue is enhanced by including a confocal slit in the system to significantly suppress the out-of-focus background and the associated noise.With all the technical improvements,our method captures threedimensional superresolved image stacks of neuronal structures in mouse brain tissue samples for a depth range of more than 200μm.
基金Funded by the Postdoctor Science Fund of China (No. 20070410715) Shanghai Excellent Youth Special Fund (No. 17014)
文摘A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD software UG NX3.0 was used to design the macro channels＇ shape, size and distribution. By integrating rapid prototyping and traditional porogen technique, the macro channels and micro pores were formed respectively. The size, shape and quantity of micro pores were controlled by porogen particulates. The sintered β-TCP porous scaffolds possessed connective macro channels of approximately 500 μm and micro pores of 200-400 μm. The porosity and connectivity of micro pores became higher with the increase of porogen ratio, while the mechanical properties weakened. The average porosity and compressive strength offl-TCP scaffolds prepared with porogen ratio of 60wt% were 78.12% and 0.2983 MPa, respectively. The cells＇ adhesion ratio of scaffolds was 67.43%. The ALP activity, OCN content and cells micro morphology indicated that cells grew and proliferated well on the scaffolds.
基金Supported by Science and Technology Planning Projects of China during the 12th Five-year Plan-key Techniques of High Quality and High Efficiency Production of Fruit Trees(2014BAD16B07)Central Finance Forestry Science and Technology Extension Project(ZYLTKJTG2015017)National Featured Fruit Trees Root Stock Germplasm Resources Platform(Luntai)(NICGR2017-60)
文摘To study the effects of different concentrations of Abscisic Acid(ABA) on leaf tissue structure of Korla fragrant pear and lay the foundation for the cultivation and regulation of Korla fragrant pear. Using the paraffin section method, the leaf thickness, the epidermis thickness, the palisade tissue thickness and the sponge tissue thickness were measured; palisade spongy ratio, Cell Tightness(CT) and Cell Looseness(CL) were examined after treatments with exogenous ABA. Leaf thickness, leaf palisade spongy ratio and palisade tissue thickness increased significantly after exogenous ABA treatment compared with CK, while the effect on leaf epidermis was not obvious. The leaf thickness and palisade tissue thickness increased evidently after 70 mg · LABA treatment by 24.89% and 41.10%, respectively. The tissue structures of leaves were more compact, while CL was lower after 70 and 90 mg · LABA treatments. The effects of different concentrations of exogenous ABA could increase the leaf thickness, palisade tissue thickness of Korla fragrant pear and CT, reduced the thickness of spongy tissue and CL. Among those concentrations of exogenous ABA, the effect of spraying 70 mg · Lexogenous ABA was suitable for improving cold resistance of Korla fragrant pear.
基金Project supported by the National Key Research and Development Program,China(Grant No.2016YFF0203000)the National Natural Science Foundation of China(Grant Nos.11774167 and 61571222)+2 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.020414380001)the State Key Laboratory of Acoustics,Chinese Academy of Sciences(Grant No.SKLA201609)AQSIQ Technology Research and Development Program,China(Grant No.2017QK125)
文摘In order to improve the operability and accuracy of high-intensity focused ultrasound （HIFU）, an annular focused transducer, whereby a B-ultrasound probe is placed in its center, is used to realize the real time monitoring and control of the treatment. In this paper, the spheroidal beam equation （SBE） was used to calculate the sound lield by an annular focused transducer with a wide aperture angle to first derive the heat deposition and the Pennes equation was used to calculate the temperature field in multi-layer tissue. We studied the effect of different parameters on the temperature of the tissues. The result shows that the focal length has a significant influence on both maximum liver temperature rise and skin temperature rise, and both increase with the increase in the focal length. When the frequency increases, the temperature rise first undergoes a rapid increase before gradually reaching a maximum, and then finally decreasing. The temperature rise increases while the inner radius decreases or the sound pressure increases. By choosing suitable parameters, the proper temperature rise both on the target tissue and skin via an annular tbcused transducer with a wide aperture angle can be obtained.
基金This work was financially supported by the National Key Research and Development Program of China(2018YFA0703000)the NationalNatural Science Foundation of China(81670972,31872752)+1 种基金Key Research and Development Program of Zhejiang,China(2017C01054,2018C03062,2017C01063)Postdoctoral Science Foundation of China(2020TQ0257,2020M681896).
文摘The organized alignment of cells in various tissues plays a significant role in the maintenance of specific functions.To induce such an alignment,ideal scaffolds should simulate the characteristics and morphologies of natural tissues.Aligned structures that guide cell orientation are used to facilitate tissue regeneration and repair.We here review how various aligned structures are fabricated,including aligned electrospun nanofibers,aligned porous or channeled structures,micropatterns and combinations thereof,and their application in nerve,skeletal muscle,tendon,and tubular dentin regeneration.The future use of aligned structures in tissue engineering is also discussed.
基金supported by National Natural Science Foundation of China(Nos.12075046 and 11775042)。
文摘A two-dimensional electromagnetic particle-in-cell simulation model is proposed to study the density evolution and collective stopping of electron beams in background plasmas.We show here the formation of the multi-layer structure of the relativistic electron beam in the plasma due to the different betatron frequency from the beam front to the beam tail.Meanwhile,the nonuniformity of the longitudinal wakefield is the essential reason for the multi-layer structure formation in beam phase space.The influences of beam parameters(beam radius and transverse density profile)on the formation of the multi-layer structure and collective stopping in background plasmas are also considered.
基金Supported by Project of Key Discipline Pratacultural Science of Hunan Province during the Twelfth Five-Year Plan Period(540390211002)
文摘[Objectives] To study the underground stem tissue structure and agronomic traits of different populations of wild Houttuynia cordata Thumb. [Methods] 8 different populations of wild Houttuynia cordata Thumb. in southern China were selected,the preliminary study was carried out about underground stem tissue structure( stem wall thickness,underground stem cross section diameter,medullary cavity,large vascular bundle area,small vascular bundle area,and number of vascular bundles),and main agronomic traits of aboveground and underground parts. [Results]There were significant differences in the underground stem tissue structure and agronomic traits of some populations of wild Houttuynia cordata Thumb. [Conclusions] From comparison,it reached the conclusion that the populations of wild Houttuynia cordata Thumb. in Kunming of Yunnan,Hechuan of Chongqing,and Nanning of Guangxi showed better underground stem tissue structure and agronomic traits. The results are expected to provide certain guidance for cultivation,reasonable development,and utilization of wild populations of Houttuynia cordata Thumb.
文摘With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.
基金Projects(42477162,52108347,52178371,52168046,52178321,52308383)supported by the National Natural Science Foundation of ChinaProjects(2023C03143,2022C01099,2024C01219,2022C03151)supported by the Zhejiang Key Research and Development Plan,China+6 种基金Project(LQ22E080010)supported by the Exploring Youth Project of Zhejiang Natural Science Foundation,ChinaProject(LR21E080005)supported by the Outstanding Youth Project of Natural Science Foundation of Zhejiang Province,ChinaProject(2022M712964)supported by the Postdoctoral Science Foundation of ChinaProject(2023AFB008)supported by the Natural Science Foundation of Hubei Province for Youth,ChinaProject(202203)supported by Engineering Research Centre of Rock-Soil Drilling&Excavation and Protection,Ministry of Education,ChinaProject(202305-2)supported by the Science and Technology Project of Zhejiang Provincial Communication Department,ChinaProject(2021K256)supported by the Construction Research Founds of Department of Housing and Urban-Rural Development of Zhejiang Province,China。
文摘This study proposes a general imperfect thermal contact model to predict the thermal contact resistance at the interface among multi-layered composite structures.Based on the Green-Lindsay(GL)thermoelastic theory,semi analytical solutions of temperature increment and displacement of multi-layered composite structures are obtained by using the Laplace transform method,upon which the effects of thermal resistance coefficient,partition coefficient,thermal conductivity ratio and heat capacity ratio on the responses are studied.The results show that the generalized imperfect thermal contact model can realistically describe the imperfect thermal contact problem.Accordingly,it may degenerate into other thermal contact models by adjusting the thermal resistance coefficient and partition coefficient.
基金National Natural Science Foundation Council of China(Grant No.52305359)Hubei Provincial Natural Science Foundation of China(Grant No.2023AFB141)National Medical Products Administration Key Laboratory for Dental Materials(PKUSS20240401)。
文摘In tissue engineering(TE),tissue-inducing scaffolds are a promising solution for organ and tissue repair owing to their ability to attract stem cells in vivo,thereby inducing endogenous tissue regeneration through topological cues.An ideal TE scaffold should possess biomimetic cross-scale structures,similar to that of natural extracellular matrices,at the nano-to macro-scale level.Although freeform fabrication of TE scaffolds can be achieved through 3D printing,this method is limited in simultaneously building multiscale structures.To address this challenge,low-temperature fields were adopted in the traditional fabrication processes,such as casting and 3D printing.Ice crystals grow during scaffold fabrication and act as a template to control the nano-and micro-structures.These microstructures can be optimized by adjusting various parameters,such as the direction and magnitude of the low-temperature field.By preserving the macro-features fabricated using traditional methods,additional micro-structures with smaller scales can be incorporated simultaneously,realizing cross-scale structures that provide a better mimic of natural organs and tissues.In this paper,we present a state-of-the-art review of three low-temperature-field-assisted fabrication methods—freeze casting,cryogenic3D printing,and freeze spinning.Fundamental working principles,fabrication setups,processes,and examples of biomedical applications are introduced.The challenges and outlook for low-temperature-assisted fabrication are also discussed.
基金This work was supported by the National Science Fund for Distinguished Young Scholars(Grant No.11625210)the National Science Foundation of China(Grant No.51873153)+1 种基金the Shanghai Pujiang Program(Grant No.19PJ1410000)the Shanghai International Science and Technology Cooperation Fund Project(Grant No.19520713000).
文摘In this study,a high impact resistant multi-layered composite consisting of continuous carbon fibre/nylon(CCF)and short carbon fibre/nylon(SCF)layers is developed via 3D printing technology.The effect of CCF/SCF layers configuration on the impact resistance is investigated by low-velocity impact test,and the impact failure mechanism of the 3D printed composites is explored by microscopic observations and finite element(FE)simulation analysis.The results show that the 3D printed multi-layered composite with SCF layers distributed in the middle(HFA)exhibits higher impact resistant performance than the specimens with alternating SCF/CCF layers(HFB)and CCF layers distributed in the middle(HFC).The effect of CCF/SCF layers proportion on the impact performance is also studied by FE simulation,and the results show that the specimen with a CCF/SCF proportion of 7.0 exhibits the highest impact strength.
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)Canadian Foundation for Innovation(CFI)
文摘Gold nanoparticles(GNPs) are emerging as a novel tool to improve existing cancer therapeutics. GNPs are being used as radiation dose enhancers in radiation therapy as well as anticancer drugs carriers in chemotherapy. However,the success of GNP-based therapeutics depends on their ability to penetrate tumor tissue. GNPs of 20 and 50 nm diameters were used to elucidate the effects of size on the GNP interaction with tumor cells at monolayer and multilayer level. At monolayer cell level, smaller NPs had a lower uptake compared to larger NPs at monolayer cell level. However, the order was reversed at tissue-like multilayer level. The smaller NPs penetrated better compared to larger NPs in tissue-like materials.Based on our study using tissue-like materials, we can predict that the smaller NPs are better for future therapeutics due to their greater penetration in tumor tissue once leaving the leaky blood vessels. In this study, tissue-like multilayer cellular structures(MLCs) were grown to model the post-vascular tumor environment. The MLCs exhibited a much more extensive extracellular matrix than monolayer cell cultures. The MLC model can be used to optimize the nano–micro interface at tissue level before moving into animal models. This would accelerate the use of NPs in future cancer therapeutics.
基金Project(2011DFB70230)supported by State International Cooperation Program of ChinaProject(N110403003)supported by Basic Research Foundation of Education Ministry of China
文摘Artificial bone with porous structure is crucial for tissue scaffold and clinic implants.Scaffold provides structure support for cells and guides tissues regeneration for final tissue structure.A computational aided process of porous bone modeling was developed which described the design and fabrication of tissue scaffolds by considering intricate architecture,porosity and pore size.To simulate intricate bone structure,different constructive units were presented.In modeling process,bone contour was gotten from computed tomography(CT)images and was divided into two levels.Each level was represented by relatively reconstructive process.Pore size distribution was controlled by using mesh generation.The whole hexahedral mesh was reduced by unit structure,when a 3D mesh with various hexahedral elements was provided.The simulation results show that constructive structure of porous scaffold can meet the needs of clinic implants in accurate and controlled way.
