Flow diverter devices are small stents used to divert blood flow away from aneurysms in the brain,stagnating flow and inducing intra-aneurysmal thrombosis which in time will prevent aneurysm rupture.Current devices ar...Flow diverter devices are small stents used to divert blood flow away from aneurysms in the brain,stagnating flow and inducing intra-aneurysmal thrombosis which in time will prevent aneurysm rupture.Current devices are formed from thin(~25μm)wires which will remain in place long after the aneurysm has been mitigated.As their continued presence could lead to secondary complications,an absorbable flow diverter which dissolves into the body after aneurysm occlusion is desirable.The absorbable metals investigated to date struggle to achieve the necessary combination of strength,elasticity,corrosion rate,fragmentation resistance,radiopacity,and biocompatibility.This work proposes and investigates a new composite wire concept combining absorbable iron alloy(FeMnN)shells with one or more pure molybdenum(Mo)cores.Various wire configurations are produced and drawn to 25–250μm wires.Tensile testing revealed high and tunable mechanical properties on par with existing flow diverter materials.In vitro degradation testing of 100μm wire in DMEM to 7 days indicated progressive corrosion and cracking of the FeMnN shell but not of the Mo,confirming the cathodic protection of the Mo by the FeMnN and thus mitigation of premature fragmentation risk.In vivo implantation and subsequentμCT of the same wires in mouse aortas to 6 months showed meaningful corrosion had begun in the FeMnN shell but not yet in the Mo filament cores.In total,these results indicate that these composites may offer an ideal combination of properties for absorbable flow diverters.展开更多
Currently,cell culture models play a key role in determining cell behavior under various conditions.However,the accurate simulation of cellular behavior that imitates the body’s conditions remains a challenge.Therefo...Currently,cell culture models play a key role in determining cell behavior under various conditions.However,the accurate simulation of cellular behavior that imitates the body’s conditions remains a challenge.Therefore,to overcome this obstacle,three-dimensional cell culture models have been developed.Microfluidic tissues/organs-on-chips(TOOCs)are new devices that have provided the opportunity to culture cells in a medium that is almost similar to the physiological conditions of the body.TOOCs can be designed in simple or complex models,which are mostly fabricated by soft lithography.These novel structures have been developed to mimic the conditions of various tissues and organs;however,microfluidic models for oral and dental tissues have not yet been widely used.The application of TOOCs for oral tissues/organs can provide the opportunity to study cell interactions with biomaterials used in dentistry.Furthermore,TOOCs can provide the opportunity to study the cellular interactions and developmental stages of oral tissues/organs more accurately.This review of the current advances in the field of TOOC development for oral tissues provides a comprehensive understanding of this burgeoning concept,shows the progress and applications of these novel models in the imitation of oral tissues/organs thus far,and reveals the limitations that TOOCs confront.Moreover,it suggests further perspectives for future applications.展开更多
There has been a growing need for high specific power electrical machines for a wide range of applications.These include hybrid/electric traction applications,and aerospace applications.A lot of work has been done to ...There has been a growing need for high specific power electrical machines for a wide range of applications.These include hybrid/electric traction applications,and aerospace applications.A lot of work has been done to accomplish significantly higher specific power electrical machines especially for aerospace applications.Several machine topologies as well as thermal management schemes have been proposed.Even though there has been a few publications that provided an overview of high-speed and high specific power electrical machines[1-3],the goal of this paper is to provide a more comprehensive review of high specific power electrical machines with special focus on machines that have been built and tested and are considered the leading candidates defining the state-of-the art.Another key objective of this paper is to highlight the key“system-level”tradeoffs involved in pushing electrical machines to higher specific power.Focusing solely on the machine specific power can lead to a sub-optimal solution at the system-level.展开更多
There has been a revived and growing role for electrical machines and drives across a wide range of applications.Such applications include,hybrid/electrical traction applications,aerospace applications,and renewable e...There has been a revived and growing role for electrical machines and drives across a wide range of applications.Such applications include,hybrid/electrical traction applications,aerospace applications,and renewable energy.All these applications present different set of requirements and challenges.The common trend is that there is a need for higher-performance electrical machines in terms of higher power/torque density,and higher efficiency while keeping cost under control.There has been a lot of work done around coming up with novel machine topologies,optimizing more conventional topologies as well as improved thermal management schemes.Like many other areas of engineering/research,advanced materials can play a key role in opening up the design space for electrical machines leading to a step improvement in their performance.This paper will present an overview of some of the key advanced materials that are either recently developed or are currently under development and their potential impact on electrical machines.展开更多
Wounds heal through a complex process including four phases.Any interruption or interference in healing process can prevent wound healing.Infection is one of the most common complications preventing wounds from healin...Wounds heal through a complex process including four phases.Any interruption or interference in healing process can prevent wound healing.Infection is one of the most common complications preventing wounds from healing.In this study,we investigated the fibroblast cell morphology and behavior of a gelatin-based hydrogel containing anthocyanin to determine whether it can be used for early detection of infection.The experimental results ascertained that 6 h after culturing the fibroblasts,they could be well attached to the surface of the hydrogel,and 48 h after seeding,they were spread over the surface and connected with each other.After the addition of a low dose of anthocyanin,the vitality of the cell increased,and the results of the ATR-FTIR analysis showed that anthocyanin could eliminate remaining glutaraldehyde free radicals.Anthocyanin also could change its color after the addition of bacterial supernatant.Thus,hydrogels containing black carrot anthocyanin may be a potential therapeutic and diagnostic strategy to promote wound healing and early detection of infection.展开更多
Transdermal drug delivery systems have overcome many limitations of other drug administration routes,such as injection pain and first-pass metabolism following oral route,although transdermal drug delivery systems are...Transdermal drug delivery systems have overcome many limitations of other drug administration routes,such as injection pain and first-pass metabolism following oral route,although transdermal drug delivery systems are limited to drugs with low molecular weight.Hence,new emerging technology allowing high molecular weight drug delivery across the skin—known as‘microneedles’—has been developed,which creates microchannels that facilitate drug delivery.In this report,drug-loaded degradable conic microneedles are modeled to characterize the degradation rate and drug release profile.Since a lot of data are available for polylactic acid-co-glycolic acid(PLGA)degradation in the literature,PLGA of various molecular weights-as a biodegradable polymer in the polyester family-is used for modeling and verification of the drug delivery in themicroneedles.The main reaction occurring during polyester degradation is hydrolysis of steric bonds,leading to molecular weight reduction.The acid produced in the degradation has a catalytic effect on the reaction.Changes in water,acid and steric bond concentrations over time and for different radii of microneedles are investigated.To solve the partial and ordinary differential equations simultaneously,finite difference and Runge–Kutta methods are employed,respectively,with the aid of MATLAB.Correlation of the polymer degradation rate with its molecular weight and molecular weight changes versus time are illustrated.Also,drug diffusivity is related to matrix molecular weight.The molecular weight reduction and accumulative drug release within the system are predicted.In order to validate and assess the proposed model,data series of the hydrolytic degradation of aspirin(180.16 Da)-and albumin(66,000 Da)-loaded PLGA(1:1 molar ratio)are used for comparison.The proposed model is in good agreement with experimental data from the literature.Considering diffusion as themain phenomena and autocatalytic effects in the reaction,the drug release profile is predicted.Based on our results for a microneedle containing drug,we are able to estimate drug release rates before fabrication.展开更多
Proposing new statistical distributions which are more flexible than the existing distributions have become a recent trend in the practice of distribution theory.Actuaries often search for new and appropriate statisti...Proposing new statistical distributions which are more flexible than the existing distributions have become a recent trend in the practice of distribution theory.Actuaries often search for new and appropriate statistical models to address data related to financial and risk management problems.In the present study,an extension of the Lomax distribution is proposed via using the approach of the weighted T-X family of distributions.The mathematical properties along with the characterization of the new model via truncated moments are derived.The model parameters are estimated via a prominent approach called the maximum likelihood estimation method.A brief Monte Carlo simulation study to assess the performance of the model parameters is conducted.An application to medical care insurance data is provided to illustrate the potentials of the newly proposed extension of the Lomax distribution.The comparison of the proposed model is made with the(i)Two-parameter Lomax distribution,(ii)Three-parameter models called the half logistic Lomax and exponentiated Lomax distributions,and(iii)A four-parameter model called the Kumaraswamy Lomax distribution.The statistical analysis indicates that the proposed model performs better than the competitive models in analyzing data in financial and actuarial sciences.展开更多
Because of the dispersion at the nanometer level, polymer-clay nanocomposites exhibit superior properties in comparison with pure polymer or conventional composites; this includes properties such as barrier properties...Because of the dispersion at the nanometer level, polymer-clay nanocomposites exhibit superior properties in comparison with pure polymer or conventional composites; this includes properties such as barrier properties , improved thermal stability and flame retardancy. The outstanding properties of polymer-clay nanocomposites are achieved at a much lower volume fraction, compared with conventional composites. Polymer-clay nanocomposites can be processed using common techniques, such as extrusion and casting, which are superior to the cumbersome techniques used for the conventional composites. Hence, polymer-clay nanocomposites have important potential commercial value.展开更多
The rational design of double active sites system is vital for constructing high-efficiency iron sulfides electrocatalysts towards hydrogen evolution reaction(HER) in alkaline media. However, it remains a challenge to...The rational design of double active sites system is vital for constructing high-efficiency iron sulfides electrocatalysts towards hydrogen evolution reaction(HER) in alkaline media. However, it remains a challenge to controllably create the high-density interface of double sites for optimal synergistic effect.Herein, we reported a simple chemical oxidation-induced surface reconfiguration strategy to obtain the interface-rich Fe_(3)O_(4)-FeS nanoarray supported on iron foam(Fe_(3)O_(4)-FeS/IF) using FeS nanosheets as precursors. The abundant Fe_(3)O_(4)-FeS interfaces could improve the dispersion of active sites and facilitate the electron transfer, leading to enhanced hydrogen evolution efficiency. And meanwhile, by altering the oxidation temperature, the content of S and O could be effectively controlled, further achieving the ratio optimization of Fe_(3)O_(4)to FeS. Synchrotron-based X-ray absorption near-edge structure, X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy consistently confirm the changes of electronic structure and d-band center of Fe_(3)O_(4)-FeS after chemical oxidation. Consequently, Fe_(3)O_(4)-FeS/IF exhibits excellent alkaline HER activity with a low overpotential of 120.8 mV to reach 20 mA cm^(-2),and remains stable ranging from 10, 20 to 50 mA cm^(-2) for each 20 h, respectively. Therefore, the facile and controllable chemical oxidation may be an effective strategy for designing high-density interfaces of transition metal-based sulfides towards alkaline HER.展开更多
The popular singer and songwriter Bruce Springsteen is a product of the working-class family, and his songs often creatively capture not only working-class life but also workers＇ alienation from their labor. In an un...The popular singer and songwriter Bruce Springsteen is a product of the working-class family, and his songs often creatively capture not only working-class life but also workers＇ alienation from their labor. In an unsystematic way, Springsteen＇s lyrics portray how modem workers are alienated from the products of their labor, the process of working, other workers, and ultimately, from themselves. Although Springsteen primarily has blue-collar, industrial workers in mind, his thoughts on the alienation of labor continue to have relevance for workers in the American consumer society and in the contemporary global economy as well.展开更多
Contemporary Hollywood films seem at first glance to be opposed to capital punishment. However, this article＇s consideration of five surprisingly similar films （Dead Man Walking, The Chamber, Last Dance, True Crime,...Contemporary Hollywood films seem at first glance to be opposed to capital punishment. However, this article＇s consideration of five surprisingly similar films （Dead Man Walking, The Chamber, Last Dance, True Crime, and The Life of David Gale） finds that they do not truly and consistently condemn capital punishment. Instead of suggesting that the practice of capital punishment is fundamentally immoral and should in general be ended, the films champion only worthy individuals on death row and delight primarily in the personal growth of other characters who attempt to aid the condemned. In the end, Hollywood offers only a muted message regarding the on-going use of capital punishment.展开更多
Reptile sex determination is attracting much attention because the great diversity of sex-determination and dosage compensation mechanisms permits us to approach fundamental questions about mechanisms of sex chromosom...Reptile sex determination is attracting much attention because the great diversity of sex-determination and dosage compensation mechanisms permits us to approach fundamental questions about mechanisms of sex chromosome turnover. Recent studies have made significant progress in better understanding diversity and conservation of reptile sex chromosomes, with however no reptile master sex determination genes identified. Here we describe an integrated genomics and cytogenetics pipeline,combining probes generated from the microdissected sex chromosomes with transcriptome and genome sequencing to explore the sex chromosome diversity in non-model Australian reptiles. We tested our pipeline on a turtle, two species of geckos, and a monitor lizard. Genes identified on sex chromosomes were compared to the chicken genome to identify homologous regions among the four species. We identified candidate sex determining genes within these regions, including conserved vertebrate sex-determining genes pdgfa,pdgfra amh and wt1, and demonstrated their testis or ovary-specific expression. All four species showed gene-by-gene rather than chromosome-wide dosage compensation. Our results imply that reptile sex chromosomes originated by independent acquisition of sex-determining genes on different autosomes,as well as translocations between different ancestral macro-and microchromosomes.We discuss the evolutionary drivers of the slow differentiation and turnover of reptile sex chromosomes.展开更多
Locking plate fixation is being widely applied for fixation of forearm fractures and has many potential advantages, such as fixed angle fixation and improved construct stability, especially in osteoporotic bone. Biome...Locking plate fixation is being widely applied for fixation of forearm fractures and has many potential advantages, such as fixed angle fixation and improved construct stability, especially in osteoporotic bone. Biomechanical data comparing locking devices to commonly used Low Contact Dynamic Compression （LCDCP） plates for the fixation of forearm fractures has been lacking. The purpose of this study was to compare the fixation stability of a 3.5-mm unicortical locked plate with bicortical non-locked LCDCP plates. Six matched pairs of fresh frozen cadaveric forearms were randomly assigned to unicortical locked and bicortical unlocked groups. Non-destructive four-point bending and torsional test was performed on the ulna and radius separately, using a servohydraulic testing system to obtain construct stiffness of the intact specimens and specimens after osteotomy and plating. The specimens were then loaded to failure to test the fixation strength. The locked unicortical fixation showed significantly higher bending stiffness than the unlocked bicortical fixation, but with significantly lower stiffness and strength in torsion. Fixation strength was comparable between the two groups under bending, but significantly greater in the bicortical non-locked group under torsion. Findings from this study suggest that postoperative rehabilitation protocols may need modification to limit torsional loading in the early stage when using locked unicortical fixation. The study also points out the potential advantage of a hybrid fixation that combines locked unicortical and unlocked bicortical screws.展开更多
The paper discusses the generalization of constrained Bayesian method （CBM） for arbitrary loss functions and its application for testing the directional hypotheses. The problem is stated in terms of false and tru...The paper discusses the generalization of constrained Bayesian method （CBM） for arbitrary loss functions and its application for testing the directional hypotheses. The problem is stated in terms of false and true discovery rates. One more criterion of estimation of directional hypotheses tests quality, the Type III errors rate, is considered. The ratio among discovery rates and the Type III errors rate in CBM is considered. The advantage of CBM in comparison with Bayes and frequentist methods is theoretically proved and demonstrated by an example.展开更多
Piezoelectric(PZ)energy has been paid attention to as conventional renewable energy sources including solar,wind,and geothermal power.To address the dilemma of climatic conditions affecting the energy harvesting using...Piezoelectric(PZ)energy has been paid attention to as conventional renewable energy sources including solar,wind,and geothermal power.To address the dilemma of climatic conditions affecting the energy harvesting using Lead Zirconate Titanate(PZT)in pavement,wafer-boxes were used with embedded PZT sensors,since wafer-boxes have the ability to be embedded in the pavement where sensors are protected from any kind of physical damage.This research project was designed to identify which shaped wafer-box produced the most electric voltage and power.Various forms of wafer-box were developed to identify if there was any potential difference in voltage generation due to the structural shapes of the box.Seven different shapes of prototype wafer-boxes were designed utilizing both a 3D printer and 3D Computer Aided Design(CAD).These wafer-boxes were coupled with embedded PZT sensors which were tested in asphalt pavement analyzer(APA)machine under certain load to produce electric voltage.Collected voltage data from the APA wheel load test(WLT)were analyzed using various statistical methods.The statistical analyses results indicated that out of the seven different shaped wafer-boxes,the right-angled triangular shaped box produced the highest average voltage values where’s square shaped wafer-box produced the lowest amount of voltage.Structural properties of a wafer-box in terms of section modulus,area moment of inertia,extreme points,and radius of gyration were also analyzed,and a regression analysis was conducted to identify the reasons of different amounts of voltage produced.These voltage values could be used to calculate the power using power formulas showing relationship between power and voltage values.The outcome helped to identify which shape is most effective to power generation under certain circumstances.The regression analysis results indicated that out of four properties the section modulus is the most influential structural property affecting voltage production.展开更多
基金support of Carlo Wolf(School of Mechanical Engineering,University of Applied Sciences Stralsund)for support with the CT analysis and metallographic preparation,Aubrey L.Ehle(Indiana University School of Medicine)for support with the radiopacity assessment,and Amani Gillette(Morgridge Institute for Research)for support with the cytotoxicity analysis.Parts of this study were completed using Michigan Technological University’s Applied Chemical and Morphological Analysis Laboratory.RG and NP were partially supported by NIH R15HL167221.AO is supported by American Heart Association grant 23PRE1012781.
文摘Flow diverter devices are small stents used to divert blood flow away from aneurysms in the brain,stagnating flow and inducing intra-aneurysmal thrombosis which in time will prevent aneurysm rupture.Current devices are formed from thin(~25μm)wires which will remain in place long after the aneurysm has been mitigated.As their continued presence could lead to secondary complications,an absorbable flow diverter which dissolves into the body after aneurysm occlusion is desirable.The absorbable metals investigated to date struggle to achieve the necessary combination of strength,elasticity,corrosion rate,fragmentation resistance,radiopacity,and biocompatibility.This work proposes and investigates a new composite wire concept combining absorbable iron alloy(FeMnN)shells with one or more pure molybdenum(Mo)cores.Various wire configurations are produced and drawn to 25–250μm wires.Tensile testing revealed high and tunable mechanical properties on par with existing flow diverter materials.In vitro degradation testing of 100μm wire in DMEM to 7 days indicated progressive corrosion and cracking of the FeMnN shell but not of the Mo,confirming the cathodic protection of the Mo by the FeMnN and thus mitigation of premature fragmentation risk.In vivo implantation and subsequentμCT of the same wires in mouse aortas to 6 months showed meaningful corrosion had begun in the FeMnN shell but not yet in the Mo filament cores.In total,these results indicate that these composites may offer an ideal combination of properties for absorbable flow diverters.
基金supported by the National Institute of Dental&Craniofacial Research of the National Institutes of Health(Nos.R15DE027533,R56 DE029191,and 3R15DE027533-01A1W1).
文摘Currently,cell culture models play a key role in determining cell behavior under various conditions.However,the accurate simulation of cellular behavior that imitates the body’s conditions remains a challenge.Therefore,to overcome this obstacle,three-dimensional cell culture models have been developed.Microfluidic tissues/organs-on-chips(TOOCs)are new devices that have provided the opportunity to culture cells in a medium that is almost similar to the physiological conditions of the body.TOOCs can be designed in simple or complex models,which are mostly fabricated by soft lithography.These novel structures have been developed to mimic the conditions of various tissues and organs;however,microfluidic models for oral and dental tissues have not yet been widely used.The application of TOOCs for oral tissues/organs can provide the opportunity to study cell interactions with biomaterials used in dentistry.Furthermore,TOOCs can provide the opportunity to study the cellular interactions and developmental stages of oral tissues/organs more accurately.This review of the current advances in the field of TOOC development for oral tissues provides a comprehensive understanding of this burgeoning concept,shows the progress and applications of these novel models in the imitation of oral tissues/organs thus far,and reveals the limitations that TOOCs confront.Moreover,it suggests further perspectives for future applications.
文摘There has been a growing need for high specific power electrical machines for a wide range of applications.These include hybrid/electric traction applications,and aerospace applications.A lot of work has been done to accomplish significantly higher specific power electrical machines especially for aerospace applications.Several machine topologies as well as thermal management schemes have been proposed.Even though there has been a few publications that provided an overview of high-speed and high specific power electrical machines[1-3],the goal of this paper is to provide a more comprehensive review of high specific power electrical machines with special focus on machines that have been built and tested and are considered the leading candidates defining the state-of-the art.Another key objective of this paper is to highlight the key“system-level”tradeoffs involved in pushing electrical machines to higher specific power.Focusing solely on the machine specific power can lead to a sub-optimal solution at the system-level.
文摘There has been a revived and growing role for electrical machines and drives across a wide range of applications.Such applications include,hybrid/electrical traction applications,aerospace applications,and renewable energy.All these applications present different set of requirements and challenges.The common trend is that there is a need for higher-performance electrical machines in terms of higher power/torque density,and higher efficiency while keeping cost under control.There has been a lot of work done around coming up with novel machine topologies,optimizing more conventional topologies as well as improved thermal management schemes.Like many other areas of engineering/research,advanced materials can play a key role in opening up the design space for electrical machines leading to a step improvement in their performance.This paper will present an overview of some of the key advanced materials that are either recently developed or are currently under development and their potential impact on electrical machines.
文摘Wounds heal through a complex process including four phases.Any interruption or interference in healing process can prevent wound healing.Infection is one of the most common complications preventing wounds from healing.In this study,we investigated the fibroblast cell morphology and behavior of a gelatin-based hydrogel containing anthocyanin to determine whether it can be used for early detection of infection.The experimental results ascertained that 6 h after culturing the fibroblasts,they could be well attached to the surface of the hydrogel,and 48 h after seeding,they were spread over the surface and connected with each other.After the addition of a low dose of anthocyanin,the vitality of the cell increased,and the results of the ATR-FTIR analysis showed that anthocyanin could eliminate remaining glutaraldehyde free radicals.Anthocyanin also could change its color after the addition of bacterial supernatant.Thus,hydrogels containing black carrot anthocyanin may be a potential therapeutic and diagnostic strategy to promote wound healing and early detection of infection.
文摘Transdermal drug delivery systems have overcome many limitations of other drug administration routes,such as injection pain and first-pass metabolism following oral route,although transdermal drug delivery systems are limited to drugs with low molecular weight.Hence,new emerging technology allowing high molecular weight drug delivery across the skin—known as‘microneedles’—has been developed,which creates microchannels that facilitate drug delivery.In this report,drug-loaded degradable conic microneedles are modeled to characterize the degradation rate and drug release profile.Since a lot of data are available for polylactic acid-co-glycolic acid(PLGA)degradation in the literature,PLGA of various molecular weights-as a biodegradable polymer in the polyester family-is used for modeling and verification of the drug delivery in themicroneedles.The main reaction occurring during polyester degradation is hydrolysis of steric bonds,leading to molecular weight reduction.The acid produced in the degradation has a catalytic effect on the reaction.Changes in water,acid and steric bond concentrations over time and for different radii of microneedles are investigated.To solve the partial and ordinary differential equations simultaneously,finite difference and Runge–Kutta methods are employed,respectively,with the aid of MATLAB.Correlation of the polymer degradation rate with its molecular weight and molecular weight changes versus time are illustrated.Also,drug diffusivity is related to matrix molecular weight.The molecular weight reduction and accumulative drug release within the system are predicted.In order to validate and assess the proposed model,data series of the hydrolytic degradation of aspirin(180.16 Da)-and albumin(66,000 Da)-loaded PLGA(1:1 molar ratio)are used for comparison.The proposed model is in good agreement with experimental data from the literature.Considering diffusion as themain phenomena and autocatalytic effects in the reaction,the drug release profile is predicted.Based on our results for a microneedle containing drug,we are able to estimate drug release rates before fabrication.
文摘Proposing new statistical distributions which are more flexible than the existing distributions have become a recent trend in the practice of distribution theory.Actuaries often search for new and appropriate statistical models to address data related to financial and risk management problems.In the present study,an extension of the Lomax distribution is proposed via using the approach of the weighted T-X family of distributions.The mathematical properties along with the characterization of the new model via truncated moments are derived.The model parameters are estimated via a prominent approach called the maximum likelihood estimation method.A brief Monte Carlo simulation study to assess the performance of the model parameters is conducted.An application to medical care insurance data is provided to illustrate the potentials of the newly proposed extension of the Lomax distribution.The comparison of the proposed model is made with the(i)Two-parameter Lomax distribution,(ii)Three-parameter models called the half logistic Lomax and exponentiated Lomax distributions,and(iii)A four-parameter model called the Kumaraswamy Lomax distribution.The statistical analysis indicates that the proposed model performs better than the competitive models in analyzing data in financial and actuarial sciences.
基金Support by the Natural Science Foundation (51064006, 41272064) of ChinaGuangxi Science Foundation (2011GXNSFD 018008)Open Fund of Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (KLMM20110202)
文摘Because of the dispersion at the nanometer level, polymer-clay nanocomposites exhibit superior properties in comparison with pure polymer or conventional composites; this includes properties such as barrier properties , improved thermal stability and flame retardancy. The outstanding properties of polymer-clay nanocomposites are achieved at a much lower volume fraction, compared with conventional composites. Polymer-clay nanocomposites can be processed using common techniques, such as extrusion and casting, which are superior to the cumbersome techniques used for the conventional composites. Hence, polymer-clay nanocomposites have important potential commercial value.
基金financially supported by National Natural Science Foundation of China (52174283)the Qingdao Science and Technology Benefiting People Special Project (20-3-4-8-nsh)+1 种基金the Fundamental Research Funds for the Central Universities(20CX02212A)the Development Fund of State Key Laboratory of Heavy Oil Processing and the Postgraduate Innovation Project of China University of Petroleum (YCX2020042)。
文摘The rational design of double active sites system is vital for constructing high-efficiency iron sulfides electrocatalysts towards hydrogen evolution reaction(HER) in alkaline media. However, it remains a challenge to controllably create the high-density interface of double sites for optimal synergistic effect.Herein, we reported a simple chemical oxidation-induced surface reconfiguration strategy to obtain the interface-rich Fe_(3)O_(4)-FeS nanoarray supported on iron foam(Fe_(3)O_(4)-FeS/IF) using FeS nanosheets as precursors. The abundant Fe_(3)O_(4)-FeS interfaces could improve the dispersion of active sites and facilitate the electron transfer, leading to enhanced hydrogen evolution efficiency. And meanwhile, by altering the oxidation temperature, the content of S and O could be effectively controlled, further achieving the ratio optimization of Fe_(3)O_(4)to FeS. Synchrotron-based X-ray absorption near-edge structure, X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy consistently confirm the changes of electronic structure and d-band center of Fe_(3)O_(4)-FeS after chemical oxidation. Consequently, Fe_(3)O_(4)-FeS/IF exhibits excellent alkaline HER activity with a low overpotential of 120.8 mV to reach 20 mA cm^(-2),and remains stable ranging from 10, 20 to 50 mA cm^(-2) for each 20 h, respectively. Therefore, the facile and controllable chemical oxidation may be an effective strategy for designing high-density interfaces of transition metal-based sulfides towards alkaline HER.
文摘The popular singer and songwriter Bruce Springsteen is a product of the working-class family, and his songs often creatively capture not only working-class life but also workers＇ alienation from their labor. In an unsystematic way, Springsteen＇s lyrics portray how modem workers are alienated from the products of their labor, the process of working, other workers, and ultimately, from themselves. Although Springsteen primarily has blue-collar, industrial workers in mind, his thoughts on the alienation of labor continue to have relevance for workers in the American consumer society and in the contemporary global economy as well.
文摘Contemporary Hollywood films seem at first glance to be opposed to capital punishment. However, this article＇s consideration of five surprisingly similar films （Dead Man Walking, The Chamber, Last Dance, True Crime, and The Life of David Gale） finds that they do not truly and consistently condemn capital punishment. Instead of suggesting that the practice of capital punishment is fundamentally immoral and should in general be ended, the films champion only worthy individuals on death row and delight primarily in the personal growth of other characters who attempt to aid the condemned. In the end, Hollywood offers only a muted message regarding the on-going use of capital punishment.
基金supported by the National Natural Science Foundation of China (32170415, 32061130208)Natural Science Foundation of Zhejiang Province (LD19C190001)+6 种基金European Research Council Starting Grant (677696) to Q.Z.supported by an ARC FT (FT110100733)partially supported by ARC DP (DP110102262) led by T.E.University of Canberra Strategic Research Fund awarded to T.E.supported by an ARC DP (DP110102262) led by T.E.supported by NSF (IOS1146820)supported by the University of Canberra postgraduate research scholarships。
文摘Reptile sex determination is attracting much attention because the great diversity of sex-determination and dosage compensation mechanisms permits us to approach fundamental questions about mechanisms of sex chromosome turnover. Recent studies have made significant progress in better understanding diversity and conservation of reptile sex chromosomes, with however no reptile master sex determination genes identified. Here we describe an integrated genomics and cytogenetics pipeline,combining probes generated from the microdissected sex chromosomes with transcriptome and genome sequencing to explore the sex chromosome diversity in non-model Australian reptiles. We tested our pipeline on a turtle, two species of geckos, and a monitor lizard. Genes identified on sex chromosomes were compared to the chicken genome to identify homologous regions among the four species. We identified candidate sex determining genes within these regions, including conserved vertebrate sex-determining genes pdgfa,pdgfra amh and wt1, and demonstrated their testis or ovary-specific expression. All four species showed gene-by-gene rather than chromosome-wide dosage compensation. Our results imply that reptile sex chromosomes originated by independent acquisition of sex-determining genes on different autosomes,as well as translocations between different ancestral macro-and microchromosomes.We discuss the evolutionary drivers of the slow differentiation and turnover of reptile sex chromosomes.
文摘Locking plate fixation is being widely applied for fixation of forearm fractures and has many potential advantages, such as fixed angle fixation and improved construct stability, especially in osteoporotic bone. Biomechanical data comparing locking devices to commonly used Low Contact Dynamic Compression （LCDCP） plates for the fixation of forearm fractures has been lacking. The purpose of this study was to compare the fixation stability of a 3.5-mm unicortical locked plate with bicortical non-locked LCDCP plates. Six matched pairs of fresh frozen cadaveric forearms were randomly assigned to unicortical locked and bicortical unlocked groups. Non-destructive four-point bending and torsional test was performed on the ulna and radius separately, using a servohydraulic testing system to obtain construct stiffness of the intact specimens and specimens after osteotomy and plating. The specimens were then loaded to failure to test the fixation strength. The locked unicortical fixation showed significantly higher bending stiffness than the unlocked bicortical fixation, but with significantly lower stiffness and strength in torsion. Fixation strength was comparable between the two groups under bending, but significantly greater in the bicortical non-locked group under torsion. Findings from this study suggest that postoperative rehabilitation protocols may need modification to limit torsional loading in the early stage when using locked unicortical fixation. The study also points out the potential advantage of a hybrid fixation that combines locked unicortical and unlocked bicortical screws.
文摘The paper discusses the generalization of constrained Bayesian method （CBM） for arbitrary loss functions and its application for testing the directional hypotheses. The problem is stated in terms of false and true discovery rates. One more criterion of estimation of directional hypotheses tests quality, the Type III errors rate, is considered. The ratio among discovery rates and the Type III errors rate in CBM is considered. The advantage of CBM in comparison with Bayes and frequentist methods is theoretically proved and demonstrated by an example.
文摘Piezoelectric(PZ)energy has been paid attention to as conventional renewable energy sources including solar,wind,and geothermal power.To address the dilemma of climatic conditions affecting the energy harvesting using Lead Zirconate Titanate(PZT)in pavement,wafer-boxes were used with embedded PZT sensors,since wafer-boxes have the ability to be embedded in the pavement where sensors are protected from any kind of physical damage.This research project was designed to identify which shaped wafer-box produced the most electric voltage and power.Various forms of wafer-box were developed to identify if there was any potential difference in voltage generation due to the structural shapes of the box.Seven different shapes of prototype wafer-boxes were designed utilizing both a 3D printer and 3D Computer Aided Design(CAD).These wafer-boxes were coupled with embedded PZT sensors which were tested in asphalt pavement analyzer(APA)machine under certain load to produce electric voltage.Collected voltage data from the APA wheel load test(WLT)were analyzed using various statistical methods.The statistical analyses results indicated that out of the seven different shaped wafer-boxes,the right-angled triangular shaped box produced the highest average voltage values where’s square shaped wafer-box produced the lowest amount of voltage.Structural properties of a wafer-box in terms of section modulus,area moment of inertia,extreme points,and radius of gyration were also analyzed,and a regression analysis was conducted to identify the reasons of different amounts of voltage produced.These voltage values could be used to calculate the power using power formulas showing relationship between power and voltage values.The outcome helped to identify which shape is most effective to power generation under certain circumstances.The regression analysis results indicated that out of four properties the section modulus is the most influential structural property affecting voltage production.
