With the increase in the use of electronic devices in many different environments,a need has arisen for an easily implemented method for the rapid,sensitive detection of liquids in the vicinity of electronic component...With the increase in the use of electronic devices in many different environments,a need has arisen for an easily implemented method for the rapid,sensitive detection of liquids in the vicinity of electronic components.In this work,a high-performance power generator that combines carbon nanoparticles and TiO2 nanowires has been fabricated by sequential electrophoretic deposition(EPD).The opencircuit voltage and short-circuit current of a single generator are found to exceed 0.7 V and 100μA when 6μL of water was applied.The generator is also found to have a stable and reproducible response to other liquids.An output voltage of 0.3 V was obtained after 244,876,931,and 184μs,on exposure of the generator to 6μL of water,ethanol,acetone,and methanol,respectively.The fast response time and high sensitivity to liquids show that the device has great potential for the detection of small quantities of liquid.In addition,the simple easily implemented sequential EPD method ensures the high mechanical strength of the device.This compact,reliable device provides a new method for the sensitive,rapid detection of extraneous liquids before they can impact the performance of electronic circuits,particularly those on printed circuit board.展开更多
The widespread use of agrochemicals and its possible negative impacts on humans and the environment remains a highly topical and controversial issue. Of particular concern here are chemicals that can disturb an organ...The widespread use of agrochemicals and its possible negative impacts on humans and the environment remains a highly topical and controversial issue. Of particular concern here are chemicals that can disturb an organism's endocrine system. Referring to the precautionary principle, the objective of the research project start2 is to develop management strategies that help reduce possible risks for httmans and the environment of endocrine active agrochemicals. As an empirical basis we combined qualitative and quantitative methods and initiated two expert dialogues. Our findings underpin the well known fact that the use of agrochemicals is complex and dependent on more than the individual attitudes of farmers. Agricultural plant protection management is the collective product of a complex agricultural system, which encompasses treatment, marketing, industry and agricultural consultation as well as agricultural teaching institutions and relevant scientific disciplines. Successful management strategies for risk reduction in the context of hormonally active agrochemicals thus need to involve all actors within this system. The paper proposes a strategy that promotes participation by enabling learning processes among these actors.展开更多
Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents ...Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).展开更多
It has become the hot topic of new normal for environmental protection to " impel ecological civilization and create new way of environ- mental protection". In this paper, based on current severe environmental prote...It has become the hot topic of new normal for environmental protection to " impel ecological civilization and create new way of environ- mental protection". In this paper, based on current severe environmental protection situation, new idea of "government taking the stage, research department writing a play,enterprise acting in an opera and the masses supervising" and action plan of "government having the right but can not be impulsive, research department having the talent and should discharge their duties, enterprise having the money but should keep law, and the mas- ses having the enthusiasm to strengthen supervision" for environmental protection are proposed,which aims to contribute ideas and exert efforts for impelling ecological civilization and environmental protection.展开更多
This paper examines how cybersecurity is developing and how it relates to more conventional information security. Although information security and cyber security are sometimes used synonymously, this study contends t...This paper examines how cybersecurity is developing and how it relates to more conventional information security. Although information security and cyber security are sometimes used synonymously, this study contends that they are not the same. The concept of cyber security is explored, which goes beyond protecting information resources to include a wider variety of assets, including people [1]. Protecting information assets is the main goal of traditional information security, with consideration to the human element and how people fit into the security process. On the other hand, cyber security adds a new level of complexity, as people might unintentionally contribute to or become targets of cyberattacks. This aspect presents moral questions since it is becoming more widely accepted that society has a duty to protect weaker members of society, including children [1]. The study emphasizes how important cyber security is on a larger scale, with many countries creating plans and laws to counteract cyberattacks. Nevertheless, a lot of these sources frequently neglect to define the differences or the relationship between information security and cyber security [1]. The paper focus on differentiating between cybersecurity and information security on a larger scale. The study also highlights other areas of cybersecurity which includes defending people, social norms, and vital infrastructure from threats that arise from online in addition to information and technology protection. It contends that ethical issues and the human factor are becoming more and more important in protecting assets in the digital age, and that cyber security is a paradigm shift in this regard [1].展开更多
Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibra...Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equa- tion of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal super- position. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.展开更多
In this study, a safety enhanced Salmonella Pullorum (S. Pullorum) ghost was constructed using an antimicrobial peptide gene, and evaluated for its potential as a Pullorum disease (PD) vaccine candidate. The antim...In this study, a safety enhanced Salmonella Pullorum (S. Pullorum) ghost was constructed using an antimicrobial peptide gene, and evaluated for its potential as a Pullorum disease (PD) vaccine candidate. The antimicrobial peptide SMAP29 was co-expressed with lysis gene E to generate S. Pullorum ghosts. No viable bacteria were detectable either in the fermentation culture after induction of gene E- and SMAP29-mediated lysis for 24 h or in the lyophilized ghost products. Specific-pathogen- free (SPF) chicks were intraperitoneally immunized with ghosts at day 7 of age and no mortality, clinical symptoms or signs of PD such as anorexia, depression and diarrhea were observed. On challenge with a virulent S. Pullorum strain at 4 wk post-immunization, a comparatively higher level of protection was observed in the S. Pullorum ghost immunized chickens with a minimum of pathological lesions and bacterial loads compared to the birds in inactivated vaccine groups. In addition, immunization with the S. Pullorum ghosts induced a potent systemic IgG response and was associated with significantly increased levels of cytokine IFN-y and IL-4 and relative percentages of CD4+ and CD8+ T lymphocytes. Our results indicate that SMAP29 can be employed as a new secondary lethal protein to enhance the safety of bacterial ghosts, and to prepare a non-living bacterial vaccine candidate that can prevent PD in chickens.展开更多
Our lab has shown that brief electrical nerve stimulation(ES)has a dramatic impact on remyelination of lysophosphatidyl choline(LPC)-induced focally demyelinated rat peripheral nerves,while also inducing an axon-prote...Our lab has shown that brief electrical nerve stimulation(ES)has a dramatic impact on remyelination of lysophosphatidyl choline(LPC)-induced focally demyelinated rat peripheral nerves,while also inducing an axon-protective phenotype and shifting macrophages from a predominantly pro-inflammatory toward a pro-repair phenotype.Whether this same potential exists in the central nervous system is not known.Thus,for proof of principle studies,the peripheral nerve demyelination and ES model was adapted to the central nervous system,whereby a unilateral focal LPC-induced demyelination of the dorsal column at the lumbar enlargement where the sciatic nerve afferents enter was created,so that subsequent ipsilateral sciatic nerve ES results in increased neural activity in the demyelinated axons.Data reveal a robust focal demyelination at 7 days post-LPC injection.Delivery of 1-hour ES at 7 days post-LPC polarizes macrophages/microglia toward a pro-repair phenotype when examined at 14 days post-LPC;results in smaller LPC-associated regions of inflammation compared to non-stimulated controls;results in significantly more cells of the oligodendroglial lineage in the demyelinated region;elevates myelin basic protein levels;and shifts the paranodal protein Caspr along demyelinated axons to a more restricted distribution,consistent with reformation of the paranodes of the nodes of Ranvier.ES also significantly enhanced levels of phosphorylated neurofilaments detected in the zones of demyelination,which has been shown to confer axon protection.Collectively these findings support that strategies that increase neural activity,such as brief electrical stimulation,can be beneficial for promoting intrinsic repair following focal demyelinating insults in demyelinating diseases such as multiple sclerosis.All animal procedures performed were approved by the University of Saskatchewan's Animal Research Ethics Board(protocol#20090087;last approval date:November 5,2020).展开更多
The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed paramete...The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer.展开更多
The epidermal tissues of the cuticular membrane(CM)and periderm membrane(PM)confer first-line protection from environmental stresses in terrestrial plants.Although PM protection is essentially ubiquitous in plants,the...The epidermal tissues of the cuticular membrane(CM)and periderm membrane(PM)confer first-line protection from environmental stresses in terrestrial plants.Although PM protection is essentially ubiquitous in plants,the protective mechanism,the function of many transcription factors and enzymes,and the genetic control of metabolic signaling pathways are poorly understood.Different microphenotypes and cellular components in russet(PM-covered)and green(CM-covered)fruit skins of pear were revealed by scanning and transmission electron microscopy.The two types of fruit skins showed distinct phytohormone accumulation,and different transcriptomic and proteomic profiles.The enriched pathways were detected by differentially expressed genes and proteins from the two omics analyses.A detailed analysis of the suberin biosynthesis pathways identified the regulatory signaling network,highlighting the general mechanisms required for periderm formation in russet fruit skin.The regulation of aquaporins at the protein level should play an important role in the specialized functions of russet fruit skin and PM-covered plant tissues.展开更多
The effect of a protection zone on a diffusion predator-prey model with Ivlev-type functional response is considered.We discuss the existence and non-existence of positive steady state solutions by using the bifurcati...The effect of a protection zone on a diffusion predator-prey model with Ivlev-type functional response is considered.We discuss the existence and non-existence of positive steady state solutions by using the bifurcation theory.It is shown that the protection zone for prey has beneficial effects on the coexistence of the two species when the growth rate of predator is positive.Moreover,we examine the dependence of the coexistence region on the efficiency of the predator capture of the prey and the protection zone.展开更多
In this study, the Single Factor Test(SFT) was used to optimize the pre-freezing conditions of L. plantarum KLDS1.0391(KLDS1.0391). Further, the Freeze-Drying Protective Agents(FDPA) of KLDS1.0391 was optimized ...In this study, the Single Factor Test(SFT) was used to optimize the pre-freezing conditions of L. plantarum KLDS1.0391(KLDS1.0391). Further, the Freeze-Drying Protective Agents(FDPA) of KLDS1.0391 was optimized by Response Surface Methodology(RSM). The optimum pretreatment conditions were as the follows: initial concentration of KLDS1.0391 was 1011 CFU · m L-1 and KLDS1.0391 was pre-freezed at –80℃ for 8 h to achieve the survival rate of 46.21%. The main components of FDPA were skim milk, sucrose, sodium glutamate and Tween-80. And the influence of four factors on the survival rate of KLDS1.0391 in freeze-drying was in order as the follows: skim milk〉sucrose〉Tween-80〉sodium glutamate. The optimal FDPA composition was skim milk 11.3%, sucrose 9.8%, sodium glutamate 5.1% and Tween-80 0.2%. Under the above conditions, the survival rate of the cells was 82.98%. Comparing the predicted values, the relative error was 0.37% and the difference was not significant, which indicated that the established model could effectively reflect the actual protection of FDPA to KLDS1.0391.展开更多
A theoretical analysis is presented to predict the nonlinear thermo-structural response of metallicsandwich panels with truss cores under through-thickness gradient temperature field, which is acommon service condit...A theoretical analysis is presented to predict the nonlinear thermo-structural response of metallicsandwich panels with truss cores under through-thickness gradient temperature field, which is acommon service condition for metallic thermal protection system (TPS). The in-planetemperature distribution is assumed to be uniform, and through-thickness temperature field isdetermined by heat conduction. Two typical conditions are analyzed: nonlinear thermal bendingin fixed inside surface temperature, and thermal post-buckling in fixed temperature differencebetween two surfaces. Temperature-dependent mechanical properties are considered, andgradient shear stiffness and bending stiffness due to non-uniform temperature is included. Resultsindicate that the temperature-dependent material properties obviously affect bending resistance;however, the effect is negligible on post-buckling behavior. Influences of geometric parameters onthe thermo-structural behavior of the sandwich panel according to the present theoretical modelare discussed.展开更多
[Objective] This study aimed to investigate the protective effects of proteins, salts, sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method] Different types, combinati...[Objective] This study aimed to investigate the protective effects of proteins, salts, sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method] Different types, combinations, ratios and concentrations of protective agents were designed. Under simulated conditions, the optimal protective agent formulation was screened for improving the survival rate and survival time of soybean rhizobium strain HW-05. The optimal combination of significant factors was determined by Box-Behnken central composite design. [Result] Three significant factors affecting effective number of viable cells were screened, including peptone, xanthan gum and NaCl. The final concentration of each compound was optimized 0. 13% peptone, 0.011% xanthan gum, 0.30% NaCl. [Conclusion] After addition of protective agent and preservation at room temperature for six months, effective number of viable cells of soybean rhizobium strain HW-05 reached 3.185 ×10^8 CFU/ml. The survival rate of HW-05 cells was improved by more than 25% compared with the control group (2.458×10^8 CFU /ml).展开更多
The purpose of this study was to investigate the protective effect of low dose radiation on TCE induced oxidative damage in rats. The oxidative damage of both liver and kidney was assessed by serum alkaline phosphatas...The purpose of this study was to investigate the protective effect of low dose radiation on TCE induced oxidative damage in rats. The oxidative damage of both liver and kidney was assessed by serum alkaline phosphatase (ALP), Gamma Glutamyl Trans-Peptidase (GGTP), Alanine and Aspartate Amino Transferase (ALT & AST) activities in addition concentrations of cholesterol, high density lipoprotein-cholesterol (HDL-c), low density lipoprotein-cholesterol (LDL-c), Triacyglycerols (TGs), urea and creatinine were analyzed. Liver lipid peroxidation (MDA), Nitric Oxide (NO), reduced glutathione (GSH) levels, and activities of both Super-Oxide Dismutase (SOD) and Glutathione Peroxidase (GSH-Px) were measured. Results: TCE administration increase serum ALP, GGTP, ALT, AST activities, cholesterol, triacylglycerols, LDL-c, urea and creatinine concentrations, besides liver MDA and NO, whereas it decreased SOD, GSH-Px activities, GSH level in liver, HDL-c in serum. Low dose of gamma rays (0.5 Gy) exposure significantly improved lipid peroxidation and oxidative injury induced by TCE. Conclusion: The study indicates that treatment with low dose of gamma rays ameliorate harmful effects induced by TCE taking in consideration the effect of gamma radiation as a stimulant of radical detoxification.展开更多
According to the data from Investigation Report of Land Use Change in China,The Land Resources Communique of China and Chronicle of Statistical Data for Five Decades of New China issued from Ministry of Land Resources...According to the data from Investigation Report of Land Use Change in China,The Land Resources Communique of China and Chronicle of Statistical Data for Five Decades of New China issued from Ministry of Land Resources,we select two indices:change of farmland quantity and policy of farmland protection.According to econometric theory,by using Eviewes 5.1 software,co-integration analysis,Granger causality test,impulse response and other analysis methods,we analyze the relationship between change of farmland quantity and policy of farmland protection in China since the reform and opening-up.The results show that there is long-term balanced relationship between change of farmland quantity and policy of farmland protection,and there is a certain mechanism restricting motion of variables between the two so as to make the two deviate from each other little and step towards balance in the long run;there is unilateral causality relationship between farmland change and policy of farmland protection,namely that the farmland change is the Granger cause of policy of farmland protection,while policy of farmland protection is not the Granger cause of farmland change;impulse response and variance decomposition indicate that farmland change plays the role of promoting policy of farmland protection continuously,and the role is strengthened along with prolonged lag period;the policy of farmland protection has strong inertia,because it is impacted by the former level of itself,and the policy of farmland protection plays insignificant role in promoting farmland quantity.Consequently,the important approach of solving problem of rapid decrease of farmland is to formulate long-term strategy,strengthen theoretical research of farmland protection and reinforce degree of formulation,implementation and surveillance of farmland protection policy.展开更多
Thermal protective clothing has been recognized as the primary shielding against emergency fire hazard and inflammable gas leakage. Therefore,the thermal response of human covered with thermal protective clothing unde...Thermal protective clothing has been recognized as the primary shielding against emergency fire hazard and inflammable gas leakage. Therefore,the thermal response of human covered with thermal protective clothing under high temperature is the key work to investigate the thermal insulation of thermal protective clothing. A coupling model composed of thermal protective clothing,air gap and human skin is established and the temperature of the micro-system is numerically solved via the finite element method( FEM).Especially,the heat transfer of air gap located between clothing and human skin considering conduction and radiation is established while the human skin layers involve the effect of blood perfusion. Then the effect of thermophysical properties( thermal conductivity and volumetric capacity) of fabric and thickness of fabric and air on the thermal response of the micro-system is elucidated and compared.The results indicate that the volumetric heat capacity of fabric is the key parameter to affect the thermal shielding performance of thermal protective clothing,and the thicker fabric thickness and air gap thickness can improve the thermal protective properties of the micro-system.展开更多
基金supported by the Natural Sciences and Engineering Research Council (NSERC)Canada Research Chairs (CRC) Programs+2 种基金the financial support from the National Natural Science Foundation of China (51975033)the Beijing Natural Science Foundation (3192020)the China Scholarship Council (CSC) for the graduate fellowship
文摘With the increase in the use of electronic devices in many different environments,a need has arisen for an easily implemented method for the rapid,sensitive detection of liquids in the vicinity of electronic components.In this work,a high-performance power generator that combines carbon nanoparticles and TiO2 nanowires has been fabricated by sequential electrophoretic deposition(EPD).The opencircuit voltage and short-circuit current of a single generator are found to exceed 0.7 V and 100μA when 6μL of water was applied.The generator is also found to have a stable and reproducible response to other liquids.An output voltage of 0.3 V was obtained after 244,876,931,and 184μs,on exposure of the generator to 6μL of water,ethanol,acetone,and methanol,respectively.The fast response time and high sensitivity to liquids show that the device has great potential for the detection of small quantities of liquid.In addition,the simple easily implemented sequential EPD method ensures the high mechanical strength of the device.This compact,reliable device provides a new method for the sensitive,rapid detection of extraneous liquids before they can impact the performance of electronic circuits,particularly those on printed circuit board.
文摘The widespread use of agrochemicals and its possible negative impacts on humans and the environment remains a highly topical and controversial issue. Of particular concern here are chemicals that can disturb an organism's endocrine system. Referring to the precautionary principle, the objective of the research project start2 is to develop management strategies that help reduce possible risks for httmans and the environment of endocrine active agrochemicals. As an empirical basis we combined qualitative and quantitative methods and initiated two expert dialogues. Our findings underpin the well known fact that the use of agrochemicals is complex and dependent on more than the individual attitudes of farmers. Agricultural plant protection management is the collective product of a complex agricultural system, which encompasses treatment, marketing, industry and agricultural consultation as well as agricultural teaching institutions and relevant scientific disciplines. Successful management strategies for risk reduction in the context of hormonally active agrochemicals thus need to involve all actors within this system. The paper proposes a strategy that promotes participation by enabling learning processes among these actors.
基金Supported by the National High Technology Research and Development Program of China (2007AA03Z456)the National Natural Science Foundation of China (20776119, 21076169 and 31000019)+5 种基金the Xi’an Research and Development Program(NC08005, YF07078)the Scientific Research Program of Shaanxi Provincial Department of Education,China(08JK452,08JK453,JG08181,2010JC21,2010JS107,2010JS108, 2010JK876 and 2010JS109)Shaanxi Provincial Scientific Technology Research and Development Program (2007K06-03, 2010JQ2012, SJ08B03)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20096101120023, 20096101110014)NWU Graduate Innovation and Creativity Funds (08YSY17)Shaanxi Key Subject Program, China
文摘Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).
基金Supported by Special Fund for Environmental Protection Research in the Public Interest(PM-zx024-201207-046)Special Fund for Basic Research Business of Scientific Research Institutes at the Central Level in the Public Interest(PM-zx021-201212-014)
文摘It has become the hot topic of new normal for environmental protection to " impel ecological civilization and create new way of environ- mental protection". In this paper, based on current severe environmental protection situation, new idea of "government taking the stage, research department writing a play,enterprise acting in an opera and the masses supervising" and action plan of "government having the right but can not be impulsive, research department having the talent and should discharge their duties, enterprise having the money but should keep law, and the mas- ses having the enthusiasm to strengthen supervision" for environmental protection are proposed,which aims to contribute ideas and exert efforts for impelling ecological civilization and environmental protection.
文摘This paper examines how cybersecurity is developing and how it relates to more conventional information security. Although information security and cyber security are sometimes used synonymously, this study contends that they are not the same. The concept of cyber security is explored, which goes beyond protecting information resources to include a wider variety of assets, including people [1]. Protecting information assets is the main goal of traditional information security, with consideration to the human element and how people fit into the security process. On the other hand, cyber security adds a new level of complexity, as people might unintentionally contribute to or become targets of cyberattacks. This aspect presents moral questions since it is becoming more widely accepted that society has a duty to protect weaker members of society, including children [1]. The study emphasizes how important cyber security is on a larger scale, with many countries creating plans and laws to counteract cyberattacks. Nevertheless, a lot of these sources frequently neglect to define the differences or the relationship between information security and cyber security [1]. The paper focus on differentiating between cybersecurity and information security on a larger scale. The study also highlights other areas of cybersecurity which includes defending people, social norms, and vital infrastructure from threats that arise from online in addition to information and technology protection. It contends that ethical issues and the human factor are becoming more and more important in protecting assets in the digital age, and that cyber security is a paradigm shift in this regard [1].
基金supported by the Funds for Creative Research Groups of China(51021001)the National Natural Science Foundation of China(51078351)Program for New Century Excellent Talents in University,Fund of Key Laboratory of Bridge-structure Engineering and Open Fund of Key Laboratory of Road & Bridge and Underground Engineering of Gansu Province(KFJJ-11-03)
文摘Due to the wide applications of arches in underground protective structures, dynamic analysis of circular arches including soil-structure interactions is important. In this paper, an exact solution of the forced vibration of circular arches subjected to subsurface denotation forces is obtained. The dynamic soil-structure interaction is considered with the introduction of an interfacial damping between the structure element and the surrounding soil into the equa- tion of motion. By neglecting the influences of shear, rotary inertia and tangential forces and assuming the arch incompressible, the equations of motion of the buried arches were set up. Analytical solutions of the dynamic responses of the protective arches were deduced by means of modal super- position. Arches with different opening angles, acoustic impedances and rise-span ratios were analyzed to discuss their influences on an arch. The theoretical analysis suggests blast loads for elastic designs and predicts the potential failure modes for buried protective arches.
基金supported by grants from the National Key Research and Development Program of China (2016YFD0501608)the National Natural Science Foundation of China (31470893)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest,China (201403054)the National High Technology Research and Development Program of China (2011AA10A210)
文摘In this study, a safety enhanced Salmonella Pullorum (S. Pullorum) ghost was constructed using an antimicrobial peptide gene, and evaluated for its potential as a Pullorum disease (PD) vaccine candidate. The antimicrobial peptide SMAP29 was co-expressed with lysis gene E to generate S. Pullorum ghosts. No viable bacteria were detectable either in the fermentation culture after induction of gene E- and SMAP29-mediated lysis for 24 h or in the lyophilized ghost products. Specific-pathogen- free (SPF) chicks were intraperitoneally immunized with ghosts at day 7 of age and no mortality, clinical symptoms or signs of PD such as anorexia, depression and diarrhea were observed. On challenge with a virulent S. Pullorum strain at 4 wk post-immunization, a comparatively higher level of protection was observed in the S. Pullorum ghost immunized chickens with a minimum of pathological lesions and bacterial loads compared to the birds in inactivated vaccine groups. In addition, immunization with the S. Pullorum ghosts induced a potent systemic IgG response and was associated with significantly increased levels of cytokine IFN-y and IL-4 and relative percentages of CD4+ and CD8+ T lymphocytes. Our results indicate that SMAP29 can be employed as a new secondary lethal protein to enhance the safety of bacterial ghosts, and to prepare a non-living bacterial vaccine candidate that can prevent PD in chickens.
基金supported by Multiple Sclerosis Society of Canada(MSSOC),No.2362(to VMKV)Canadian Institutes of Health Research(CIHR),No.14238(to VMKV)were supported by University of Saskatchewan College of Medicine Research Awards(Co MGRADs)。
文摘Our lab has shown that brief electrical nerve stimulation(ES)has a dramatic impact on remyelination of lysophosphatidyl choline(LPC)-induced focally demyelinated rat peripheral nerves,while also inducing an axon-protective phenotype and shifting macrophages from a predominantly pro-inflammatory toward a pro-repair phenotype.Whether this same potential exists in the central nervous system is not known.Thus,for proof of principle studies,the peripheral nerve demyelination and ES model was adapted to the central nervous system,whereby a unilateral focal LPC-induced demyelination of the dorsal column at the lumbar enlargement where the sciatic nerve afferents enter was created,so that subsequent ipsilateral sciatic nerve ES results in increased neural activity in the demyelinated axons.Data reveal a robust focal demyelination at 7 days post-LPC injection.Delivery of 1-hour ES at 7 days post-LPC polarizes macrophages/microglia toward a pro-repair phenotype when examined at 14 days post-LPC;results in smaller LPC-associated regions of inflammation compared to non-stimulated controls;results in significantly more cells of the oligodendroglial lineage in the demyelinated region;elevates myelin basic protein levels;and shifts the paranodal protein Caspr along demyelinated axons to a more restricted distribution,consistent with reformation of the paranodes of the nodes of Ranvier.ES also significantly enhanced levels of phosphorylated neurofilaments detected in the zones of demyelination,which has been shown to confer axon protection.Collectively these findings support that strategies that increase neural activity,such as brief electrical stimulation,can be beneficial for promoting intrinsic repair following focal demyelinating insults in demyelinating diseases such as multiple sclerosis.All animal procedures performed were approved by the University of Saskatchewan's Animal Research Ethics Board(protocol#20090087;last approval date:November 5,2020).
基金supported by the National Key Research and Development Plan of China under Grant(2016YFB0900600XXX)
文摘The modelling of the distribution transformer winding is the starting point and serves as important basis for the transformer characteristics analysis and the lightning pulse response prediction.A distributed parameters model can depict the winding characteristics accurately,but it requires complex calculations.Lumped parameter model requires less calculations,but its applicable frequency range is not wide.This paper studies the amplitude-frequency characteristics of the lightning wave,compares the transformer modelling methods and finally proposes a modified lumped parameter model,based on the above comparison.The proposed model minimizes the errors provoked by the lumped parameter approximation,and the hyperbolic functions of the distributed parameter model.By this modification it becomes possible to accurately describe the winding characteristics and rapidly obtain the node voltage response.The proposed model can provide theoretical and experimental support to lightning protection of the distribution transformer.
基金supported by the Special Funds for China Agriculture Research System(CARS-28–03)The Key Project for New Agricultural Cultivar Breeding in Zhejiang Province,China(2016C02052-4).
文摘The epidermal tissues of the cuticular membrane(CM)and periderm membrane(PM)confer first-line protection from environmental stresses in terrestrial plants.Although PM protection is essentially ubiquitous in plants,the protective mechanism,the function of many transcription factors and enzymes,and the genetic control of metabolic signaling pathways are poorly understood.Different microphenotypes and cellular components in russet(PM-covered)and green(CM-covered)fruit skins of pear were revealed by scanning and transmission electron microscopy.The two types of fruit skins showed distinct phytohormone accumulation,and different transcriptomic and proteomic profiles.The enriched pathways were detected by differentially expressed genes and proteins from the two omics analyses.A detailed analysis of the suberin biosynthesis pathways identified the regulatory signaling network,highlighting the general mechanisms required for periderm formation in russet fruit skin.The regulation of aquaporins at the protein level should play an important role in the specialized functions of russet fruit skin and PM-covered plant tissues.
基金Supported by the National Natural Science Foundation of China(11761063).
文摘The effect of a protection zone on a diffusion predator-prey model with Ivlev-type functional response is considered.We discuss the existence and non-existence of positive steady state solutions by using the bifurcation theory.It is shown that the protection zone for prey has beneficial effects on the coexistence of the two species when the growth rate of predator is positive.Moreover,we examine the dependence of the coexistence region on the efficiency of the predator capture of the prey and the protection zone.
基金Supported by the Outstanding Youth Scientists Foundation of Harbin City(2014RFYXJ006)
文摘In this study, the Single Factor Test(SFT) was used to optimize the pre-freezing conditions of L. plantarum KLDS1.0391(KLDS1.0391). Further, the Freeze-Drying Protective Agents(FDPA) of KLDS1.0391 was optimized by Response Surface Methodology(RSM). The optimum pretreatment conditions were as the follows: initial concentration of KLDS1.0391 was 1011 CFU · m L-1 and KLDS1.0391 was pre-freezed at –80℃ for 8 h to achieve the survival rate of 46.21%. The main components of FDPA were skim milk, sucrose, sodium glutamate and Tween-80. And the influence of four factors on the survival rate of KLDS1.0391 in freeze-drying was in order as the follows: skim milk〉sucrose〉Tween-80〉sodium glutamate. The optimal FDPA composition was skim milk 11.3%, sucrose 9.8%, sodium glutamate 5.1% and Tween-80 0.2%. Under the above conditions, the survival rate of the cells was 82.98%. Comparing the predicted values, the relative error was 0.37% and the difference was not significant, which indicated that the established model could effectively reflect the actual protection of FDPA to KLDS1.0391.
基金The financial support from the National Natural Science Foundation of China (91016025, 11472276, 11602271, and 11332011)the Defense Industrial Technology Development Program of China (JCKY2016130B009)
文摘A theoretical analysis is presented to predict the nonlinear thermo-structural response of metallicsandwich panels with truss cores under through-thickness gradient temperature field, which is acommon service condition for metallic thermal protection system (TPS). The in-planetemperature distribution is assumed to be uniform, and through-thickness temperature field isdetermined by heat conduction. Two typical conditions are analyzed: nonlinear thermal bendingin fixed inside surface temperature, and thermal post-buckling in fixed temperature differencebetween two surfaces. Temperature-dependent mechanical properties are considered, andgradient shear stiffness and bending stiffness due to non-uniform temperature is included. Resultsindicate that the temperature-dependent material properties obviously affect bending resistance;however, the effect is negligible on post-buckling behavior. Influences of geometric parameters onthe thermo-structural behavior of the sandwich panel according to the present theoretical modelare discussed.
基金Supported by Fund of Heilongjiang Academy of Sciences
文摘[Objective] This study aimed to investigate the protective effects of proteins, salts, sugars and trace elements on soybean rhizobium strain HW-05 by response surface methodology. [Method] Different types, combinations, ratios and concentrations of protective agents were designed. Under simulated conditions, the optimal protective agent formulation was screened for improving the survival rate and survival time of soybean rhizobium strain HW-05. The optimal combination of significant factors was determined by Box-Behnken central composite design. [Result] Three significant factors affecting effective number of viable cells were screened, including peptone, xanthan gum and NaCl. The final concentration of each compound was optimized 0. 13% peptone, 0.011% xanthan gum, 0.30% NaCl. [Conclusion] After addition of protective agent and preservation at room temperature for six months, effective number of viable cells of soybean rhizobium strain HW-05 reached 3.185 ×10^8 CFU/ml. The survival rate of HW-05 cells was improved by more than 25% compared with the control group (2.458×10^8 CFU /ml).
文摘The purpose of this study was to investigate the protective effect of low dose radiation on TCE induced oxidative damage in rats. The oxidative damage of both liver and kidney was assessed by serum alkaline phosphatase (ALP), Gamma Glutamyl Trans-Peptidase (GGTP), Alanine and Aspartate Amino Transferase (ALT & AST) activities in addition concentrations of cholesterol, high density lipoprotein-cholesterol (HDL-c), low density lipoprotein-cholesterol (LDL-c), Triacyglycerols (TGs), urea and creatinine were analyzed. Liver lipid peroxidation (MDA), Nitric Oxide (NO), reduced glutathione (GSH) levels, and activities of both Super-Oxide Dismutase (SOD) and Glutathione Peroxidase (GSH-Px) were measured. Results: TCE administration increase serum ALP, GGTP, ALT, AST activities, cholesterol, triacylglycerols, LDL-c, urea and creatinine concentrations, besides liver MDA and NO, whereas it decreased SOD, GSH-Px activities, GSH level in liver, HDL-c in serum. Low dose of gamma rays (0.5 Gy) exposure significantly improved lipid peroxidation and oxidative injury induced by TCE. Conclusion: The study indicates that treatment with low dose of gamma rays ameliorate harmful effects induced by TCE taking in consideration the effect of gamma radiation as a stimulant of radical detoxification.
文摘According to the data from Investigation Report of Land Use Change in China,The Land Resources Communique of China and Chronicle of Statistical Data for Five Decades of New China issued from Ministry of Land Resources,we select two indices:change of farmland quantity and policy of farmland protection.According to econometric theory,by using Eviewes 5.1 software,co-integration analysis,Granger causality test,impulse response and other analysis methods,we analyze the relationship between change of farmland quantity and policy of farmland protection in China since the reform and opening-up.The results show that there is long-term balanced relationship between change of farmland quantity and policy of farmland protection,and there is a certain mechanism restricting motion of variables between the two so as to make the two deviate from each other little and step towards balance in the long run;there is unilateral causality relationship between farmland change and policy of farmland protection,namely that the farmland change is the Granger cause of policy of farmland protection,while policy of farmland protection is not the Granger cause of farmland change;impulse response and variance decomposition indicate that farmland change plays the role of promoting policy of farmland protection continuously,and the role is strengthened along with prolonged lag period;the policy of farmland protection has strong inertia,because it is impacted by the former level of itself,and the policy of farmland protection plays insignificant role in promoting farmland quantity.Consequently,the important approach of solving problem of rapid decrease of farmland is to formulate long-term strategy,strengthen theoretical research of farmland protection and reinforce degree of formulation,implementation and surveillance of farmland protection policy.
基金National Natural Science Foundations of China(Nos.51306095,51273097,51403112)China Postdoctoral Science Foundations(Nos.2014M561887,2015T80697)+1 种基金Qingdao Postdoctoral Application Research Funded Project,China(No.14-2-4-1-JCH)Qingdao Application Basic Research Funded Project,China(No.15-9-1-41-JCH)
文摘Thermal protective clothing has been recognized as the primary shielding against emergency fire hazard and inflammable gas leakage. Therefore,the thermal response of human covered with thermal protective clothing under high temperature is the key work to investigate the thermal insulation of thermal protective clothing. A coupling model composed of thermal protective clothing,air gap and human skin is established and the temperature of the micro-system is numerically solved via the finite element method( FEM).Especially,the heat transfer of air gap located between clothing and human skin considering conduction and radiation is established while the human skin layers involve the effect of blood perfusion. Then the effect of thermophysical properties( thermal conductivity and volumetric capacity) of fabric and thickness of fabric and air on the thermal response of the micro-system is elucidated and compared.The results indicate that the volumetric heat capacity of fabric is the key parameter to affect the thermal shielding performance of thermal protective clothing,and the thicker fabric thickness and air gap thickness can improve the thermal protective properties of the micro-system.