A brain tumor occurs when abnormal cells grow, sometimes very rapidly, into an abnormal mass of tissue. The tumor can infect normal tissue, so there is an interaction between healthy and infected cell. The aim of this...A brain tumor occurs when abnormal cells grow, sometimes very rapidly, into an abnormal mass of tissue. The tumor can infect normal tissue, so there is an interaction between healthy and infected cell. The aim of this paper is to propose some efficient and accurate numerical methods for the computational solution of one-dimensional continuous basic models for the growth and control of brain tumors. After computing the analytical solution, we construct approximations of the solution to the problem using a standard second order finite difference method for space discretization and the Crank-Nicolson method for time discretization. Then, we investigate the convergence behavior of Conjugate gradient and generalized minimum residual as Krylov subspace methods to solve the tridiagonal toeplitz matrix system derived.展开更多
Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive sector.Their commercialization is mainly hindered due to the cost and effectivenes...Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive sector.Their commercialization is mainly hindered due to the cost and effectiveness of using platinum(Pt)in them.The cathode catalyst layer(CL)is considered a core component in PEMFCs,and its composition often considerably affects the cell performance(V_(cell))also PEMFC fabrication and production(C_(stack))costs.In this study,a data-driven multi-objective optimization analysis is conducted to effectively evaluate the effects of various cathode CL compositions on Vcelland Cstack.Four essential cathode CL parameters,i.e.,platinum loading(L_(Pt)),weight ratio of ionomer to carbon(wt_(I/C)),weight ratio of Pt to carbon(wt_(Pt/c)),and porosity of cathode CL(ε_(cCL)),are considered as the design variables.The simulation results of a three-dimensional,multi-scale,two-phase comprehensive PEMFC model are used to train and test two famous surrogates:multi-layer perceptron(MLP)and response surface analysis(RSA).Their accuracies are verified using root mean square error and adjusted R^(2).MLP which outperforms RSA in terms of prediction capability is then linked to a multi-objective non-dominated sorting genetic algorithmⅡ.Compared to a typical PEMFC stack,the results of the optimal study show that the single-cell voltage,Vcellis improved by 28 m V for the same stack price and the stack cost evaluated through the U.S department of energy cost model is reduced by$5.86/k W for the same stack performance.展开更多
This paper presents findings on dynamic cell modeling for state-of-charge (SOC) estimation in an autonomous electric vehicle (AEV). The studied cells are Lithium-Ion Polymer-based with a nominal capacity of around 8 A...This paper presents findings on dynamic cell modeling for state-of-charge (SOC) estimation in an autonomous electric vehicle (AEV). The studied cells are Lithium-Ion Polymer-based with a nominal capacity of around 8 Ah, optimized for power-needy applications. The AEV operates in a harsh environment with rate requirements up to ±25C and highly dynamic rate profiles, unlike portable-electronic applications with constant power output and fractional C rates. SOC estimation methods effective in portable electronics may not suffice for the AEV. Accurate SOC estimation necessitates a precise cell model. The proposed SOC estimation method utilizes a detailed Kalman-filtering approach. The cell model must include SOC as a state in the model state vector. Multiple cell models are presented, starting with a simple one employing “Coulomb counting” as the state equation and Shepherd’s rule as the output equation, lacking prediction of cell relaxation dynamics. An improved model incorporates filter states to account for relaxation and other dynamics in closed-circuit cell voltage, yielding better performance. The best overall results are achieved with a method combining nonlinear autoregressive filtering and dynamic radial basis function networks. The paper includes lab test results comparing physical cells with model predictions. The most accurate models obtained have an RMS estimation error lower than the quantization noise floor expected in the battery-management-system design. Importantly, these models enable precise SOC estimation, allowing the vehicle controller to utilize the battery pack’s full operating range without overcharging or undercharging concerns.展开更多
Rett syndrome(RTT)is a progressive neurodevelopmental disorder that occurs mainly in girls with a range of typical symptoms of autism spectrum disorders.MeCP2 protein loss-of-function in neural lineage cells is the ma...Rett syndrome(RTT)is a progressive neurodevelopmental disorder that occurs mainly in girls with a range of typical symptoms of autism spectrum disorders.MeCP2 protein loss-of-function in neural lineage cells is the main cause of RTT pathogenicity.As it is still hard to understand the mechanism of RTT on the basis of only clinical patients or animal models,cell models cultured in vitro play indispensable roles.Here we reviewed the research progress in the pathogenesis of RTT at the cellular level,summarized the preclinical-research-related applications,and prospected potential future development.展开更多
Primary porcine tracheal epithelial cells(PTECs) are an appropriate model for studying the molecular mechanism of various porcine respiratory diseases, including swine-origin mycoplasmas, which are isolated from respi...Primary porcine tracheal epithelial cells(PTECs) are an appropriate model for studying the molecular mechanism of various porcine respiratory diseases, including swine-origin mycoplasmas, which are isolated from respiratory tract of pigs and mainly found on the mucosal surface surrounding swine trachea. However, the short proliferation ability of primary PTECs greatly limits their lifespan. In this study, primary PTECs were carefully isolated and cultured, and immortal PTECs were constructed by transfecting primary PTECs with the recombinant constructed plasmid pEGFPhTERT containing human telomerase reverse transcriptase(hTERT). Immortal PTECs(hTERT-PTECs) maintained both the morphological and functional characteristics of primary PTECs, as indicated by the expression of cytokeratin 18, cellcycle analysis, proliferation assay, Western blotting, telomerase activity assay, karyotype analysis and quantitative RTPCR. Compared to primary PTECs, hTERT-PTECs had an extended replicative lifespan, higher telomerase activity, and enhanced proliferative activity. In addition, this cell line resulted in a lack of transformed and grown tumors in nude mice, suggesting that it could be safely applied in further studies. Moreover, hTERT-PTECs were vulnerable to all swineorigin mycoplasmas through quantitative analysis as indicated by 50% color changing unit(CCU_(50)) calculation, and no significant differences of adhesion ability between primary and immortal PTECs were observed. For the representative swine mycoplasma Mycoplasma hyopneumoniae(Mhp), except for DNA copies quantitative real-time PCR assay, indirect immunofluorescence assay and Western blotting analysis also depicted that hTERT-PTECs was able to adhere to different Mhp strains of different virulence. In summary, like primary PTECs, hTERT-PTECs could be widely used as an adhesion cell model for swine-origin mycoplasmas and in infection studies of various porcine respiratory pathogens.展开更多
The cell model developed since 1950s is a useful tool for exploring the behavior of particle assemblages,but it demands further careful development of the outer cell boundary conditions so that interaction in a partic...The cell model developed since 1950s is a useful tool for exploring the behavior of particle assemblages,but it demands further careful development of the outer cell boundary conditions so that interaction in a particleswarm is better represented. In this paper, the cell model and its development were reviewed, and the modificationsof outer cell boundary conditions were suggested. At the cell outer boundary, the restriction of uniform liquid flowwas removed in our simulation conducted in the reference frame fixed with the particle. Zero shear stress conditionwas used to evaluate the outer boundary value of the stream function. Boundary vorticity was allowed to evolve tovalues compatible to existing stream function at the free shear outer boundary. The fore-aft symmetry of vorticitydistribution at the outer boundary is thought critical to ensure the continuity of inflow and outflow between touchingneighbor cells, and is also tested in the modified cell model. Numerical simulation in terms of stream function andvorticity based on the modified cell models was carried out to shed light on the interaction between liquid andparticles. Lower predicted drag coefficient by the modified cell models was interpreted with the feature of flowstructure. The drag coefficient from the simulation was also compared with correlations of drag coefficient reportedin literature. It is found that the modified cell model with the uniformity of external flow relaxed and the fore-aftsymmetry of boundary vorticity enforced was the most satisfactory on the overall performance of prediction.展开更多
Three-dimensional(3D)culture systems are becoming increasingly popular due to their ability to mimic tissue-like structures more effectively than the monolayer cultures.In cancer and stem cell research,the natural cel...Three-dimensional(3D)culture systems are becoming increasingly popular due to their ability to mimic tissue-like structures more effectively than the monolayer cultures.In cancer and stem cell research,the natural cell characteristics and architectures are closely mimicked by the 3D cell models.Thus,the 3D cell cultures are promising and suitable systems for various proposes,ranging from disease modeling to drug target identification as well as potential therapeutic substances that may transform our lives.This review provides a comprehensive compendium of recent advancements in culturing cells,in particular cancer and stem cells,using 3D culture techniques.The major approaches highlighted here include cell spheroids,hydrogel embedding,bioreactors,scaffolds,and bioprinting.In addition,the progress of employing 3D cell culture systems as a platform for cancer and stem cell research was addressed,and the prominent studies of 3D cell culture systems were discussed.展开更多
The symmetrical cell model is widely used to study the residual stress induced by shot peening. However,the correlation between the predicted residual stresses and the shot peening coverage, which is a big challenge f...The symmetrical cell model is widely used to study the residual stress induced by shot peening. However,the correlation between the predicted residual stresses and the shot peening coverage, which is a big challenge for the researchers of the symmetrical cell model, is still not established. Based on the dynamic stresses and the residual stresses outputted from the symmetrical cell model, the residual stresses corresponding to full coverage are evaluated by normal distribution analysis. The predicted nodal dynamic stresses with respect to four corner points indicate that the equi-biaxial stress state exists only for the first shot impact. Along with the increase of shot number, the interactions of multiple shot impacts make the fluctuation of the nodal dynamic stresses about an almost identical value more and more obvious. The mean values and standard deviations of the residual stresses gradually tend to be stable with the increase of the number of shot peening series. The mean values at each corner point are almost the same after the third peening series, which means that an equi-biaxial stress state corresponding to the full coverage of shot peening is achieved. Therefore, the mean values of the nodal residual stresses with respect to a specific transverse cross-section below the peened surface can be used to correlate the measured data by X-ray. The predicted residual stress profile agrees with the experimental results very well under 200% peening coverage. An effective correlation method is proposed for the nodal residual stresses predicted by the symmetrical cell model and the shot peening coverage.展开更多
After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer's disease. The cell model was treated with donepezil or compound Danshen tablets after ...After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer's disease. The cell model was treated with donepezil or compound Danshen tablets after culture for 72 hours. Reverse transcription-PCR showed that the mRNA expression of amyloid protein precursor decreased in all groups following culture for 24 hours, and that there was no significant difference in the amount of decrease between donepezil and compound Danshen tablets. Our results suggest that compound Danshen tablets can reduce expression of the mRNA for amyloid protein precursor in a transgenic cell model of Alzheimer's disease, with similar effects to donepezil.展开更多
An embedded cell model is presented to obtain the effective elasticmoduli for three-dimensional two-phase composites which is an exact analytic formulawithout any simplified approximation and can be expressed in an ex...An embedded cell model is presented to obtain the effective elasticmoduli for three-dimensional two-phase composites which is an exact analytic formulawithout any simplified approximation and can be expressed in an explicit form. Forthe different cells such as spherical inclusions and cracks surrounded by sphere andoblate ellipsoidal matrix, the effective elastic moduli are evaluated and the resultsare compared with those from various micromechanics models. These results showthat the present model is direct, simple and efficient to deal with three-dimensionaltwo-phase composites.展开更多
Intergranular stress corrosion cracking(ISCC) of α-brass in neutral Mattsson’s solutionwas found to be controlled by an unusual"W"-shaped galvanic cell whose cathode is thegrain boundary oxide film (G.B.0....Intergranular stress corrosion cracking(ISCC) of α-brass in neutral Mattsson’s solutionwas found to be controlled by an unusual"W"-shaped galvanic cell whose cathode is thegrain boundary oxide film (G.B.0. film) andsurface film and the anode is fresh metal atthe cracked tip on both sides of the G.B.0.film. Redox reactions involved in the cellhave been proposed here. According to thismdel, initidtion of ISCC is caused by therupturing of surface film along grain boundaries,thus forming a galvanic cell. Propagation ofISCC resulted from alternate advances of G.B.0.film and dissolution on both sides of G.B.0.film caused by the effect of electrochemicalreaction. This work developed an effective approachto investigate the embrittlement process atthe tip of the crack, by increasing the lengthof the embrittlement region through constantstrain test and distinguishing the morphologyand the nature of the corrosion products byoptical microscopy and scanning electronmicroscopy (SEH).展开更多
This presentation predicts the elastic properties of three-dimensional(3D)orthogonal woven composite(3DOWC)by finite element analysis based on micro/meso repeated unit cell(RUC)models.First,the properties of fiber yar...This presentation predicts the elastic properties of three-dimensional(3D)orthogonal woven composite(3DOWC)by finite element analysis based on micro/meso repeated unit cell(RUC)models.First,the properties of fiber yarn are obtained by analysis on a micro-scale RUC model assuming fibers in a hexagonal distribution pattern in the polymer matrix.Then a full thickness meso-scale RUC model including weft yarns,warp yarns,Z-yarns and pure resin zones is established and full stiffness matrix of the 3DOWC including the in-plane and flexural constants are predicted.For thick 3DOWC with large number of weft,warp layers,an alternative analysis method is proposed in which an inner meso-RUC and a surface meso-RUC are established,respectively.Then the properties of 3DOWC are deduced based on laminate theory and properties of the inner and surface layers.The predicted results by the above two alternative methods are in good experimental agreement.展开更多
Excessive reactive oxygen species(ROS)can cause oxidative damage and lead to various metabolic disease.Tartary buckwheat(Fagopyrum tataricum(L.)Gaertn)is a new kind of protein-rich functional food,the protein in which...Excessive reactive oxygen species(ROS)can cause oxidative damage and lead to various metabolic disease.Tartary buckwheat(Fagopyrum tataricum(L.)Gaertn)is a new kind of protein-rich functional food,the protein in which has been proved to have good antioxidant capacity.In this study,in order to further explore the antioxidant mechanism of Tartary buckwheat protein,4 peptides(CR-8,LR-8,GK-10 and SR-12)were isolated and identified from it.H2 O2 was used to induce oxidative damage to Caco-2 cells to evaluate antioxidant capacity of these peptides.The results of superoxide dismutase(SOD),total antioxidant capacity(T-AOC)and mitochondrial membrane potential etc.showed that these peptides have superior antioxidant capacity.CR-8 has the best antioxidant capacity.In order to further clarify the antioxidant mechanism of CR-8,metabolomics was used to analyze related metabolites and metabolic pathways.The results showed that after CR-8 intervention,the content of metabolites such as L-acetyl carnitine has increased.This indicated that CR-8 can improve the antioxidant capacity of damaged cells by intervening in multiple metabolic pathways.This also revealed the anti-oxidant mechanism of tartary buckwheat protein.In conclusion,it provided a theoretical basis for further studying the activity of tartary buckwheat portein and utilizing buckwheat resources.展开更多
Academic biology-medicine refers to a couple of philosophies, Organicism and Mechanism, which translates into an association of Cybernetic diagrams and molecular Reductionism. This association presents logical difficu...Academic biology-medicine refers to a couple of philosophies, Organicism and Mechanism, which translates into an association of Cybernetic diagrams and molecular Reductionism. This association presents logical difficulties which make it unsuitable to describe correctly biological effects of electromagnetic fields, EMF. But these logical difficulties may be overcome when renewing the organic cell idea by means of a Philosophy of Nature which juxtaposes causality order and sense order in the cell. The signalsome, the set of descriptive components resulting from the genome, is constantly reorganized. This remodeling may become epigenetic when the phenotype becomes transformed by experience of perceptions in a given medium, because the perception of overall information coming from the extracellular medium becomes functional within the system. In that cellular perception, it is stated that the significance base which contributes to the sense order results from the qualitative topological structure of the extracellular medium. Therefore the EMF interactions target is not only the membrane and its molecules;it is also the structure of the extracellular medium which bathes the membrane. Knowing that the sense order modulation constitutes the global soil of the (localized) causality order, it is possible to obtain a same EMF bioeffect on a membrane molecule by treating a culture of cells in its bath or by treating only the extracellular aqueous medium. Consequently, the double bioeffect resulting from EMF exposure is described simply, because the sense order, such as it results from the qualitative structuring of the medium, forms the significance base which directs the causal mechanics of the cellular answer.展开更多
Stern et al. have developed a mathematical model describing pseudo-plateau bursting of pituitary cells. This model is formulated based on the Hodgkin-Huxley scheme and described by a system of nonlinear ordinary diffe...Stern et al. have developed a mathematical model describing pseudo-plateau bursting of pituitary cells. This model is formulated based on the Hodgkin-Huxley scheme and described by a system of nonlinear ordinary differential equations. In the present study, computer simulation analysis of this model was performed to evaluate the correlation between the dynamic states of the model and two system parameters: long-lasting external stimulation (Iapp) and the time constant of delayed-rectifier potassium conductance activation (τn). Computer simulation results revealed that the model showed four different dynamic states: a hyperpolarized steady state, a depolarized steady state, a repetitive spiking state, and a bursting state. An increase in Iapp changed the dynamic states from the hyperpolarized steady state to bursting state to depolarized steady state when τn was fixed at smaller values, whereas it changed the dynamic states from the hyperpolarized steady state to bursting state to repetitive spiking state when τn was fixed at larger values. An increase in τn 1) did not change the dynamic states when Iapp was fixed at a very small value, 2) changed the dynamic states from the depolarized steady state to repetitive spiking state when Iapp was fixed at a very large value, and 3) changed the dynamic states from the depolarized steady state to bursting state to repetitive spiking state when Iapp was fixed at an intermediate value.展开更多
Endothelium is the interior layer of an artery made up of tremendous number of endothelial cells which are located side by side. Finding the effective parameters that cause the cells to obtain mechanical strength in d...Endothelium is the interior layer of an artery made up of tremendous number of endothelial cells which are located side by side. Finding the effective parameters that cause the cells to obtain mechanical strength in different morphologies is an important issue in cell biomechanics. In this work a numerical model for a single endothelial cell is developed. This model includes cell’s plasma membrane and nucleus using the traingular network of spectrin level approach. Cy-toskeleton main components such as intermediate and actin filaments as well as microtubules are the other important subsets of the simulated model. Mass and spring theory is utilized in cytoskeleton components simulation. A spreading model is applied on the cell in order to simulate the adhesion on a substrate and test the model’s qualitative performance and the result is verified by the experiment. Also deformation of the cell caused by an external compressive force is another quantitative test which is predicted by the model and the results are validated with an experimental AFM test. The two most popular morphologies of the cells resulted from this work are the cell suspension morphology which is the result of no external forces and the cell adherent morphology which is the result of cell adhesion to the extracellular matrix. The mechanical stiffness of the endothelial cell is obtained in this simulation.展开更多
Colon cancer is the third leading cause of death in the US. Herbal teas and spices may reduce the incidence of chronic diseases, including colon cancer. The objectives of this study were to determine the chemopreventi...Colon cancer is the third leading cause of death in the US. Herbal teas and spices may reduce the incidence of chronic diseases, including colon cancer. The objectives of this study were to determine the chemopreventive effects of herbal teas and cinnamon in an in-vitro cell model and to evaluate the inhibitory effects of selected extracts on enzymes associated with inflammatory disease. Effects of raspberry leaf (0.5 - 2.0 mg/mL), strawberry leaf (0.4 - 1.0 mg/mL), hibiscus flower (4.0 - 10.0 mg/mL) and cinnamon (400 - 1500 μg/mL) were evaluated for cytotoxicity, induction of caspase and DNA fragmentation in colon cancer (Caco-2) cells to determine possible chemopreventive effects. Effects of extracts on inhibition of cyclooxygenase-2 (COX-2) were also measured to determine possible anti-inflammatory potential. Caco-2 cells were obtained from American Type Culture Collection (ATCC) and maintained in Dulbecco’s Modified Eagle’s Medium with 10% fetal bovine serum. As concentrations of tea increased, LDH release from Caco-2 cells increased, with cytotoxicity ranging from 1% - 80% (hibiscus flower 1.0 mg/mL and strawberry leaf (1.0 mg/mL) for teas. All extract concentrations of herbal teas and cinnamon were able to enhance caspase-3 activity with lowest activity (4.4 mmol/ min/mL) observed in the lowest concentration of cinnamon (400 μg/mL) and highest activity (6.0 mmol/min/mL) seen in the highest concentration of raspberry leaf (2 mg/mL). Tea and spice extracts were able to induce apoptosis in Caco-2 cells exhibited by increased DNA fragmentation (expressed as enrichment factor). Enrichment factor ranged from 1.0 - 1.5 (raspberry leaf 1.0 mg/mL and hibiscus 10.0 mg/mL). Teas and cinnamon exhibited anti-inflammatory potential by inhibiting COX-2 by 0.6% - 8.0% (raspberry leaf 1.0 mg/mL and strawberry leaf 0.8 mg/mL). The results suggest that herbal teas and cinnamon may have significant benefits in chemoprevention.展开更多
Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for au...Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones.展开更多
Inhibins play important roles in the reproductive system. To evaluate whether inhibin α (1-32) fusion protein plays a role in cervical cancer growth, the plasmid pVAX-inhα was constructed and its effect on prolifera...Inhibins play important roles in the reproductive system. To evaluate whether inhibin α (1-32) fusion protein plays a role in cervical cancer growth, the plasmid pVAX-inhα was constructed and its effect on proliferation and apoptosis of the human cervical cancer cell line (Hela) was checked by flow cytometry and real-time PCR. The expression and localization of inhibin α protein were detected by RT-PCR and confocal mi- croscopy which showed that inhibin α protein was expressed and localized in the nucleus of Hela cells. Over ex- pression of inhibin α gene significantly induced cell apoptosis and ceased S phase of cell cycle. Furthermore, cell proliferation was significantly suppressed 96 h post-transfection and mRNA level of anti-apoptosis genes (Bcl-2, NFκB) were decreased but pro-apoptosis genes (Bax, wild type p53) and inhibin co receptor (TGFβR3) were increased, indicating that inhibin, through its co-receptor, might activate apoptotic and cell growth cascades which regulate proliferation and apoptosis in Hela cells. These results suggest that inhibin α (1-32) fusion pro- tein, located in the cell nucleus, can regulate Hela cells growth and apoptosis by induction of apoptotic pathways such as NFκB, Bcl-2 and p53 families. These findings may have a significant impact on future research regarding cervical cancer cell lines.展开更多
文摘A brain tumor occurs when abnormal cells grow, sometimes very rapidly, into an abnormal mass of tissue. The tumor can infect normal tissue, so there is an interaction between healthy and infected cell. The aim of this paper is to propose some efficient and accurate numerical methods for the computational solution of one-dimensional continuous basic models for the growth and control of brain tumors. After computing the analytical solution, we construct approximations of the solution to the problem using a standard second order finite difference method for space discretization and the Crank-Nicolson method for time discretization. Then, we investigate the convergence behavior of Conjugate gradient and generalized minimum residual as Krylov subspace methods to solve the tridiagonal toeplitz matrix system derived.
基金supported by the Technology Innovation Program of the Korea Evaluation Institute of Industrial Technology (KEIT)under the Ministry of Trade,Industry and Energy (MOTIE)of Republic of Korea (20012121)by the National Research Foundation of Korea (NRF)grant funded by the Korea government (MSIT) (2022M3J7A106294)。
文摘Polymer electrolyte membrane fuel cells(PEMFCs)are considered a promising alternative to internal combustion engines in the automotive sector.Their commercialization is mainly hindered due to the cost and effectiveness of using platinum(Pt)in them.The cathode catalyst layer(CL)is considered a core component in PEMFCs,and its composition often considerably affects the cell performance(V_(cell))also PEMFC fabrication and production(C_(stack))costs.In this study,a data-driven multi-objective optimization analysis is conducted to effectively evaluate the effects of various cathode CL compositions on Vcelland Cstack.Four essential cathode CL parameters,i.e.,platinum loading(L_(Pt)),weight ratio of ionomer to carbon(wt_(I/C)),weight ratio of Pt to carbon(wt_(Pt/c)),and porosity of cathode CL(ε_(cCL)),are considered as the design variables.The simulation results of a three-dimensional,multi-scale,two-phase comprehensive PEMFC model are used to train and test two famous surrogates:multi-layer perceptron(MLP)and response surface analysis(RSA).Their accuracies are verified using root mean square error and adjusted R^(2).MLP which outperforms RSA in terms of prediction capability is then linked to a multi-objective non-dominated sorting genetic algorithmⅡ.Compared to a typical PEMFC stack,the results of the optimal study show that the single-cell voltage,Vcellis improved by 28 m V for the same stack price and the stack cost evaluated through the U.S department of energy cost model is reduced by$5.86/k W for the same stack performance.
文摘This paper presents findings on dynamic cell modeling for state-of-charge (SOC) estimation in an autonomous electric vehicle (AEV). The studied cells are Lithium-Ion Polymer-based with a nominal capacity of around 8 Ah, optimized for power-needy applications. The AEV operates in a harsh environment with rate requirements up to ±25C and highly dynamic rate profiles, unlike portable-electronic applications with constant power output and fractional C rates. SOC estimation methods effective in portable electronics may not suffice for the AEV. Accurate SOC estimation necessitates a precise cell model. The proposed SOC estimation method utilizes a detailed Kalman-filtering approach. The cell model must include SOC as a state in the model state vector. Multiple cell models are presented, starting with a simple one employing “Coulomb counting” as the state equation and Shepherd’s rule as the output equation, lacking prediction of cell relaxation dynamics. An improved model incorporates filter states to account for relaxation and other dynamics in closed-circuit cell voltage, yielding better performance. The best overall results are achieved with a method combining nonlinear autoregressive filtering and dynamic radial basis function networks. The paper includes lab test results comparing physical cells with model predictions. The most accurate models obtained have an RMS estimation error lower than the quantization noise floor expected in the battery-management-system design. Importantly, these models enable precise SOC estimation, allowing the vehicle controller to utilize the battery pack’s full operating range without overcharging or undercharging concerns.
基金The Major Basic Research Project of Science and Technology of YunnanGrant/Award Number:202001BC070001 and 202105AC160041+3 种基金National Natural Science Foundation of ChinaGrant/Award Number:81930121 and 31960120The National Key Research and Development Program of ChinaGrant/Award Number:2018YFA0107902 and 2018YFA0801403。
文摘Rett syndrome(RTT)is a progressive neurodevelopmental disorder that occurs mainly in girls with a range of typical symptoms of autism spectrum disorders.MeCP2 protein loss-of-function in neural lineage cells is the main cause of RTT pathogenicity.As it is still hard to understand the mechanism of RTT on the basis of only clinical patients or animal models,cell models cultured in vitro play indispensable roles.Here we reviewed the research progress in the pathogenesis of RTT at the cellular level,summarized the preclinical-research-related applications,and prospected potential future development.
基金supported by the National Natural Science Foundation of China(31800161,31700157,31800160,31900159,and 31770193)the Natural Science Foundation of Jiangsu Province,China(BK20180297 and BK20170600)the Independent Research Project Program of Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base,Ministry of Science and Technology,China(2019sy004)。
文摘Primary porcine tracheal epithelial cells(PTECs) are an appropriate model for studying the molecular mechanism of various porcine respiratory diseases, including swine-origin mycoplasmas, which are isolated from respiratory tract of pigs and mainly found on the mucosal surface surrounding swine trachea. However, the short proliferation ability of primary PTECs greatly limits their lifespan. In this study, primary PTECs were carefully isolated and cultured, and immortal PTECs were constructed by transfecting primary PTECs with the recombinant constructed plasmid pEGFPhTERT containing human telomerase reverse transcriptase(hTERT). Immortal PTECs(hTERT-PTECs) maintained both the morphological and functional characteristics of primary PTECs, as indicated by the expression of cytokeratin 18, cellcycle analysis, proliferation assay, Western blotting, telomerase activity assay, karyotype analysis and quantitative RTPCR. Compared to primary PTECs, hTERT-PTECs had an extended replicative lifespan, higher telomerase activity, and enhanced proliferative activity. In addition, this cell line resulted in a lack of transformed and grown tumors in nude mice, suggesting that it could be safely applied in further studies. Moreover, hTERT-PTECs were vulnerable to all swineorigin mycoplasmas through quantitative analysis as indicated by 50% color changing unit(CCU_(50)) calculation, and no significant differences of adhesion ability between primary and immortal PTECs were observed. For the representative swine mycoplasma Mycoplasma hyopneumoniae(Mhp), except for DNA copies quantitative real-time PCR assay, indirect immunofluorescence assay and Western blotting analysis also depicted that hTERT-PTECs was able to adhere to different Mhp strains of different virulence. In summary, like primary PTECs, hTERT-PTECs could be widely used as an adhesion cell model for swine-origin mycoplasmas and in infection studies of various porcine respiratory pathogens.
基金Supported by the National Natural Science Foundation of China (No. 29836130).
文摘The cell model developed since 1950s is a useful tool for exploring the behavior of particle assemblages,but it demands further careful development of the outer cell boundary conditions so that interaction in a particleswarm is better represented. In this paper, the cell model and its development were reviewed, and the modificationsof outer cell boundary conditions were suggested. At the cell outer boundary, the restriction of uniform liquid flowwas removed in our simulation conducted in the reference frame fixed with the particle. Zero shear stress conditionwas used to evaluate the outer boundary value of the stream function. Boundary vorticity was allowed to evolve tovalues compatible to existing stream function at the free shear outer boundary. The fore-aft symmetry of vorticitydistribution at the outer boundary is thought critical to ensure the continuity of inflow and outflow between touchingneighbor cells, and is also tested in the modified cell model. Numerical simulation in terms of stream function andvorticity based on the modified cell models was carried out to shed light on the interaction between liquid andparticles. Lower predicted drag coefficient by the modified cell models was interpreted with the feature of flowstructure. The drag coefficient from the simulation was also compared with correlations of drag coefficient reportedin literature. It is found that the modified cell model with the uniformity of external flow relaxed and the fore-aftsymmetry of boundary vorticity enforced was the most satisfactory on the overall performance of prediction.
文摘Three-dimensional(3D)culture systems are becoming increasingly popular due to their ability to mimic tissue-like structures more effectively than the monolayer cultures.In cancer and stem cell research,the natural cell characteristics and architectures are closely mimicked by the 3D cell models.Thus,the 3D cell cultures are promising and suitable systems for various proposes,ranging from disease modeling to drug target identification as well as potential therapeutic substances that may transform our lives.This review provides a comprehensive compendium of recent advancements in culturing cells,in particular cancer and stem cells,using 3D culture techniques.The major approaches highlighted here include cell spheroids,hydrogel embedding,bioreactors,scaffolds,and bioprinting.In addition,the progress of employing 3D cell culture systems as a platform for cancer and stem cell research was addressed,and the prominent studies of 3D cell culture systems were discussed.
基金Supported by National Natural Science Foundation of China(Grant Nos.51175469,51375448)
文摘The symmetrical cell model is widely used to study the residual stress induced by shot peening. However,the correlation between the predicted residual stresses and the shot peening coverage, which is a big challenge for the researchers of the symmetrical cell model, is still not established. Based on the dynamic stresses and the residual stresses outputted from the symmetrical cell model, the residual stresses corresponding to full coverage are evaluated by normal distribution analysis. The predicted nodal dynamic stresses with respect to four corner points indicate that the equi-biaxial stress state exists only for the first shot impact. Along with the increase of shot number, the interactions of multiple shot impacts make the fluctuation of the nodal dynamic stresses about an almost identical value more and more obvious. The mean values and standard deviations of the residual stresses gradually tend to be stable with the increase of the number of shot peening series. The mean values at each corner point are almost the same after the third peening series, which means that an equi-biaxial stress state corresponding to the full coverage of shot peening is achieved. Therefore, the mean values of the nodal residual stresses with respect to a specific transverse cross-section below the peened surface can be used to correlate the measured data by X-ray. The predicted residual stress profile agrees with the experimental results very well under 200% peening coverage. An effective correlation method is proposed for the nodal residual stresses predicted by the symmetrical cell model and the shot peening coverage.
基金supported by the Bureau of Traditional Chinese Medicine of Guangdong Province, No. 2010463the National Science and Technology"12~(th) Five-years"Major Special-purpose Foundation,No.2011ZX09201-201-01
文摘After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer's disease. The cell model was treated with donepezil or compound Danshen tablets after culture for 72 hours. Reverse transcription-PCR showed that the mRNA expression of amyloid protein precursor decreased in all groups following culture for 24 hours, and that there was no significant difference in the amount of decrease between donepezil and compound Danshen tablets. Our results suggest that compound Danshen tablets can reduce expression of the mRNA for amyloid protein precursor in a transgenic cell model of Alzheimer's disease, with similar effects to donepezil.
基金The project supported by the National Natural Science Foundation of China (No.19704100) the National Natural Science Foundation of Chinese Academy of Sciences (No. KJ951-1-201)
文摘An embedded cell model is presented to obtain the effective elasticmoduli for three-dimensional two-phase composites which is an exact analytic formulawithout any simplified approximation and can be expressed in an explicit form. Forthe different cells such as spherical inclusions and cracks surrounded by sphere andoblate ellipsoidal matrix, the effective elastic moduli are evaluated and the resultsare compared with those from various micromechanics models. These results showthat the present model is direct, simple and efficient to deal with three-dimensionaltwo-phase composites.
文摘Intergranular stress corrosion cracking(ISCC) of α-brass in neutral Mattsson’s solutionwas found to be controlled by an unusual"W"-shaped galvanic cell whose cathode is thegrain boundary oxide film (G.B.0. film) andsurface film and the anode is fresh metal atthe cracked tip on both sides of the G.B.0.film. Redox reactions involved in the cellhave been proposed here. According to thismdel, initidtion of ISCC is caused by therupturing of surface film along grain boundaries,thus forming a galvanic cell. Propagation ofISCC resulted from alternate advances of G.B.0.film and dissolution on both sides of G.B.0.film caused by the effect of electrochemicalreaction. This work developed an effective approachto investigate the embrittlement process atthe tip of the crack, by increasing the lengthof the embrittlement region through constantstrain test and distinguishing the morphologyand the nature of the corrosion products byoptical microscopy and scanning electronmicroscopy (SEH).
基金BASTRI Subtopic Research about Digital Sampler Technology of Body Structure Performance Study Based on Big Data Calculation Model,China(No.MIIT Civil aircraft special purpose MJ-2017-F-20)
文摘This presentation predicts the elastic properties of three-dimensional(3D)orthogonal woven composite(3DOWC)by finite element analysis based on micro/meso repeated unit cell(RUC)models.First,the properties of fiber yarn are obtained by analysis on a micro-scale RUC model assuming fibers in a hexagonal distribution pattern in the polymer matrix.Then a full thickness meso-scale RUC model including weft yarns,warp yarns,Z-yarns and pure resin zones is established and full stiffness matrix of the 3DOWC including the in-plane and flexural constants are predicted.For thick 3DOWC with large number of weft,warp layers,an alternative analysis method is proposed in which an inner meso-RUC and a surface meso-RUC are established,respectively.Then the properties of 3DOWC are deduced based on laminate theory and properties of the inner and surface layers.The predicted results by the above two alternative methods are in good experimental agreement.
基金Shanghai Natural Science Foundation(20ZR1455800)the National Science Foundation of China(31871805)+1 种基金China Agriculture Research System(CARS-08-D2)Shanghai Municipal Education Commission(Plateau Discipline Construction Program)。
文摘Excessive reactive oxygen species(ROS)can cause oxidative damage and lead to various metabolic disease.Tartary buckwheat(Fagopyrum tataricum(L.)Gaertn)is a new kind of protein-rich functional food,the protein in which has been proved to have good antioxidant capacity.In this study,in order to further explore the antioxidant mechanism of Tartary buckwheat protein,4 peptides(CR-8,LR-8,GK-10 and SR-12)were isolated and identified from it.H2 O2 was used to induce oxidative damage to Caco-2 cells to evaluate antioxidant capacity of these peptides.The results of superoxide dismutase(SOD),total antioxidant capacity(T-AOC)and mitochondrial membrane potential etc.showed that these peptides have superior antioxidant capacity.CR-8 has the best antioxidant capacity.In order to further clarify the antioxidant mechanism of CR-8,metabolomics was used to analyze related metabolites and metabolic pathways.The results showed that after CR-8 intervention,the content of metabolites such as L-acetyl carnitine has increased.This indicated that CR-8 can improve the antioxidant capacity of damaged cells by intervening in multiple metabolic pathways.This also revealed the anti-oxidant mechanism of tartary buckwheat protein.In conclusion,it provided a theoretical basis for further studying the activity of tartary buckwheat portein and utilizing buckwheat resources.
文摘Academic biology-medicine refers to a couple of philosophies, Organicism and Mechanism, which translates into an association of Cybernetic diagrams and molecular Reductionism. This association presents logical difficulties which make it unsuitable to describe correctly biological effects of electromagnetic fields, EMF. But these logical difficulties may be overcome when renewing the organic cell idea by means of a Philosophy of Nature which juxtaposes causality order and sense order in the cell. The signalsome, the set of descriptive components resulting from the genome, is constantly reorganized. This remodeling may become epigenetic when the phenotype becomes transformed by experience of perceptions in a given medium, because the perception of overall information coming from the extracellular medium becomes functional within the system. In that cellular perception, it is stated that the significance base which contributes to the sense order results from the qualitative topological structure of the extracellular medium. Therefore the EMF interactions target is not only the membrane and its molecules;it is also the structure of the extracellular medium which bathes the membrane. Knowing that the sense order modulation constitutes the global soil of the (localized) causality order, it is possible to obtain a same EMF bioeffect on a membrane molecule by treating a culture of cells in its bath or by treating only the extracellular aqueous medium. Consequently, the double bioeffect resulting from EMF exposure is described simply, because the sense order, such as it results from the qualitative structuring of the medium, forms the significance base which directs the causal mechanics of the cellular answer.
文摘Stern et al. have developed a mathematical model describing pseudo-plateau bursting of pituitary cells. This model is formulated based on the Hodgkin-Huxley scheme and described by a system of nonlinear ordinary differential equations. In the present study, computer simulation analysis of this model was performed to evaluate the correlation between the dynamic states of the model and two system parameters: long-lasting external stimulation (Iapp) and the time constant of delayed-rectifier potassium conductance activation (τn). Computer simulation results revealed that the model showed four different dynamic states: a hyperpolarized steady state, a depolarized steady state, a repetitive spiking state, and a bursting state. An increase in Iapp changed the dynamic states from the hyperpolarized steady state to bursting state to depolarized steady state when τn was fixed at smaller values, whereas it changed the dynamic states from the hyperpolarized steady state to bursting state to repetitive spiking state when τn was fixed at larger values. An increase in τn 1) did not change the dynamic states when Iapp was fixed at a very small value, 2) changed the dynamic states from the depolarized steady state to repetitive spiking state when Iapp was fixed at a very large value, and 3) changed the dynamic states from the depolarized steady state to bursting state to repetitive spiking state when Iapp was fixed at an intermediate value.
文摘Endothelium is the interior layer of an artery made up of tremendous number of endothelial cells which are located side by side. Finding the effective parameters that cause the cells to obtain mechanical strength in different morphologies is an important issue in cell biomechanics. In this work a numerical model for a single endothelial cell is developed. This model includes cell’s plasma membrane and nucleus using the traingular network of spectrin level approach. Cy-toskeleton main components such as intermediate and actin filaments as well as microtubules are the other important subsets of the simulated model. Mass and spring theory is utilized in cytoskeleton components simulation. A spreading model is applied on the cell in order to simulate the adhesion on a substrate and test the model’s qualitative performance and the result is verified by the experiment. Also deformation of the cell caused by an external compressive force is another quantitative test which is predicted by the model and the results are validated with an experimental AFM test. The two most popular morphologies of the cells resulted from this work are the cell suspension morphology which is the result of no external forces and the cell adherent morphology which is the result of cell adhesion to the extracellular matrix. The mechanical stiffness of the endothelial cell is obtained in this simulation.
文摘Colon cancer is the third leading cause of death in the US. Herbal teas and spices may reduce the incidence of chronic diseases, including colon cancer. The objectives of this study were to determine the chemopreventive effects of herbal teas and cinnamon in an in-vitro cell model and to evaluate the inhibitory effects of selected extracts on enzymes associated with inflammatory disease. Effects of raspberry leaf (0.5 - 2.0 mg/mL), strawberry leaf (0.4 - 1.0 mg/mL), hibiscus flower (4.0 - 10.0 mg/mL) and cinnamon (400 - 1500 μg/mL) were evaluated for cytotoxicity, induction of caspase and DNA fragmentation in colon cancer (Caco-2) cells to determine possible chemopreventive effects. Effects of extracts on inhibition of cyclooxygenase-2 (COX-2) were also measured to determine possible anti-inflammatory potential. Caco-2 cells were obtained from American Type Culture Collection (ATCC) and maintained in Dulbecco’s Modified Eagle’s Medium with 10% fetal bovine serum. As concentrations of tea increased, LDH release from Caco-2 cells increased, with cytotoxicity ranging from 1% - 80% (hibiscus flower 1.0 mg/mL and strawberry leaf (1.0 mg/mL) for teas. All extract concentrations of herbal teas and cinnamon were able to enhance caspase-3 activity with lowest activity (4.4 mmol/ min/mL) observed in the lowest concentration of cinnamon (400 μg/mL) and highest activity (6.0 mmol/min/mL) seen in the highest concentration of raspberry leaf (2 mg/mL). Tea and spice extracts were able to induce apoptosis in Caco-2 cells exhibited by increased DNA fragmentation (expressed as enrichment factor). Enrichment factor ranged from 1.0 - 1.5 (raspberry leaf 1.0 mg/mL and hibiscus 10.0 mg/mL). Teas and cinnamon exhibited anti-inflammatory potential by inhibiting COX-2 by 0.6% - 8.0% (raspberry leaf 1.0 mg/mL and strawberry leaf 0.8 mg/mL). The results suggest that herbal teas and cinnamon may have significant benefits in chemoprevention.
文摘Auxetic material structures exhibit a negative Poisson ratio. The structure expands in the axial and transverse directions under tensile loading and vice versa under compression loading. Many fabricated designs for auxetic materials exist such as re-entrant hexagonal, chiral, and arrowhead geometries. This paper studies the unit cell of the re-entrant hexagonal geometry to understand how changing the internal angle and fillet radius of the structure affects the Poisson’s ratio. The material chosen for this study is acrylonitrile butadiene styrene (ABS) due to its availability and frequent use in additive manufacturing. The study was based on finite element analysis. It is observed that the direction of load applied to the unit cell affects the unit cell strain, Poisson’s ratio, and maximum load capacity before failure responses. It is noticed that the re-entrant cell starts by showing a standard non-auxetic behavior until it reaches a specific axial strain value. A quadratic correlation is identified between axial and transverse strain. Designing an auxetic structure starts with understanding the behavior of a unit cell structure. The auxetic structure design is a complex process that requires a compromise between auxetic property to be achieved and load capacity via avoiding stress concentration zones.
基金National natural Science Foundation of China(31272446)Fundamental Research Funds for the Central Universities(No.2011PY020 and 52902-0900206126).
文摘Inhibins play important roles in the reproductive system. To evaluate whether inhibin α (1-32) fusion protein plays a role in cervical cancer growth, the plasmid pVAX-inhα was constructed and its effect on proliferation and apoptosis of the human cervical cancer cell line (Hela) was checked by flow cytometry and real-time PCR. The expression and localization of inhibin α protein were detected by RT-PCR and confocal mi- croscopy which showed that inhibin α protein was expressed and localized in the nucleus of Hela cells. Over ex- pression of inhibin α gene significantly induced cell apoptosis and ceased S phase of cell cycle. Furthermore, cell proliferation was significantly suppressed 96 h post-transfection and mRNA level of anti-apoptosis genes (Bcl-2, NFκB) were decreased but pro-apoptosis genes (Bax, wild type p53) and inhibin co receptor (TGFβR3) were increased, indicating that inhibin, through its co-receptor, might activate apoptotic and cell growth cascades which regulate proliferation and apoptosis in Hela cells. These results suggest that inhibin α (1-32) fusion pro- tein, located in the cell nucleus, can regulate Hela cells growth and apoptosis by induction of apoptotic pathways such as NFκB, Bcl-2 and p53 families. These findings may have a significant impact on future research regarding cervical cancer cell lines.
