Arsenic(As)contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world.Therefore,the present study was designed...Arsenic(As)contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world.Therefore,the present study was designed to investigate the individual as well as the combined effects of exogenous silicon(Si)and sodium nitroprusside(SNP),a nitric oxide(NO)donor,on plant growth,metabolites,and antioxidant defense systems of radish(Raphanus sativus L.)plants under three different concentrations of As stress,i.e.,0.3,0.5,and 0.7 mM in a pot experiment.The results showed that As stress reduced the growth parameters of radish plants by increasing the level of oxidative stress markers,i.e.,malondialdehyde and hydrogen peroxide.However,foliar application of Si(2 mM)and pretreatment with SNP(100μM)alone as well as in combination with Si improved the plant growth parameters,i.e.,root length,fresh and dry weight of plants under As stress.Furthermore,As stress also reduced protein,and metabolites contents(flavonoids,phenolic and anthocyanin).Activities of antioxidative enzymes such as catalase(CAT),ascorbate peroxidase(APX),guaiacol peroxidase(POD),and polyphenol oxidase(PPO),as well as the content of non-enzymatic antioxidants(glutathione and ascorbic acid)decreased under As stress.In most of the parameters in radish,As III concentration showed maximum reduction,as compared to As I and II concentrations.However,the individual and combined application of Si and NO significantly alleviated the As-mediated oxidative stress in radish plants by increasing the protein,and metabolites content.Enhancement in the activities of CAT,APX,POD and PPO enzymes were recorded.Contents of glutathione and ascorbic acid were also enhanced in response to co-application of Si and NO under As stress.Results obtained were more pronounced when Si and NO were applied in combination under As stress,as compared to their individual application.In short,the current study highlights that Si and NO synergistically regulate plant growth through lowering the As-mediated oxidative stress by upregulating the metabolites content,activity of antioxidative enzymes and non-enzymatic antioxidants in radish plants.展开更多
In order to solve the problem that the ripple-effect analy- sis for the operational architecture of air defense systems (OAADS) is hardly described in quantity with previous modeling approaches, a supernetwork model...In order to solve the problem that the ripple-effect analy- sis for the operational architecture of air defense systems (OAADS) is hardly described in quantity with previous modeling approaches, a supernetwork modeling approach for the OAADS is put for- ward by extending granular computing. Based on that operational units and links are equal to different information granularities, the supernetwork framework of the OAADS is constructed as a “four- network within two-layer” structure by forming dynamic operating coalitions, and measuring indexes of the ripple-effect analysis for the OAADS are given combining with Laplace spectral radius. In this framework, via analyzing multidimensional attributes which inherit relations between operational units in different granular scales, an extended granular computing is put forward integrating with a topological structure. Then the operation process within the supernetwork framework, including transformation relations be- tween two layers in the vertical view and mapping relations among functional networks in the horizontal view, is studied in quantity. As the application case shows, comparing with previous modeling approaches, the supernetwork model can validate and analyze the operation mechanism in the air defense architecture, and the ripple-effect analysis can be used to confirm the key operational unit with micro and macro viewpoints.展开更多
Under the indoor simulant conditions, toxic effects of crude-oil-contaminated soil which was put into aquatic environment on the young fishes Carassius auratus and their hepatic antioxidant system after a 20-d exposur...Under the indoor simulant conditions, toxic effects of crude-oil-contaminated soil which was put into aquatic environment on the young fishes Carassius auratus and their hepatic antioxidant system after a 20-d exposure were investigated. Results showed that the relationship between the mortality of C. auratus and the exposed doses could be divided into 3 phases: fishes exposed to the low dose groups (0.5-5.0 g/L) were dead due to the ingestion of crude-oil-contaminated soils in aquatic environment; at the medium dose groups (5.0-25.0 g/L) fishes were dead due to the penetration of toxic substances; at the high dose groups (25.0-50.0 g/L) fishes were dead due to environmental stress. The highest mortality and death speed were found in the 1.0 g/L dose group, and the death speed was sharply increased in the 50.0 g/L dose group in the late phase of exposure. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the content of malaondialdehyde (MDA) in the hepatic tissues of C. auratus were induced significantly. The activity of SOD was increased and then decreased. It was significantly inhibited in the 50.0 g/L dose group. The activity of CAT was highly induced, and restored to a level which is little more than the control when the exposed doses exceeded 10.0 g/L. The activity of GST was the most sensitive, it was significantly induced in all dose groups, and the highest elevation was up to 6 times in the 0.5 g/L dose group comparing with the control. The MDA content was significantly elevated in the 50.0 g/L dose group, and the changes of the MDA content were opposite with the changes of GST activity.展开更多
The fire distribution can be divided into weapon assignment and firing time scheduling. The criterion of weapon allocation is that a target with greater threat has higher priority. And the criterion of firing time sch...The fire distribution can be divided into weapon assignment and firing time scheduling. The criterion of weapon allocation is that a target with greater threat has higher priority. And the criterion of firing time scheduling is that a target can be damaged with the expected probability before a specific time. A fire distribution scheme and a program for the integrated missile-gun air defense system based on a criterion of earlier damage were presented. An example was taken to illustrate its effectiveness.展开更多
Various application domains require the integration of distributed real-time or near-real-time systems with non-real-time systems.Smart cities,smart homes,ambient intelligent systems,or network-centric defense systems...Various application domains require the integration of distributed real-time or near-real-time systems with non-real-time systems.Smart cities,smart homes,ambient intelligent systems,or network-centric defense systems are among these application domains.Data Distribution Service(DDS)is a communication mechanism based on Data-Centric Publish-Subscribe(DCPS)model.It is used for distributed systems with real-time operational constraints.Java Message Service(JMS)is a messaging standard for enterprise systems using Service Oriented Architecture(SOA)for non-real-time operations.JMS allows Java programs to exchange messages in a loosely coupled fashion.JMS also supports sending and receiving messages using a messaging queue and a publish-subscribe interface.In this article,we propose an architecture enabling the automated integration of distributed real-time and non-real-time systems.We test our proposed architecture using a distributed Command,Control,Communications,Computers,and Intelligence(C4I)system.The system has DDS-based real-time Combat Management System components deployed to naval warships,and SOA-based non-real-time Command and Control components used at headquarters.The proposed solution enables the exchange of data between these two systems efficiently.We compare the proposed solution with a similar study.Our solution is superior in terms of automation support,ease of implementation,scalability,and performance.展开更多
The concept of smart power requires to combine soft and hard power. Thus, smart power is a new approach for the US politics towards the Middle East. As a consequence of smart power politics of the US, some newly membe...The concept of smart power requires to combine soft and hard power. Thus, smart power is a new approach for the US politics towards the Middle East. As a consequence of smart power politics of the US, some newly members of the EU and Turkey has become a part of missile defense system. This is a significant indicator of usage of smart power for the EU members and Turkey. The security policies and practices of the US disclose a necessity for straight allies. For this reason, the relationship between the US, the EU and Turkey may be conceptualize with reference to the concept of smart power. In the case of Missile Defense System, Turkey has agreed to be a participant of this system after signing an agreement with the US. After that, Turkish government has confronted with some interior and exterior political difficulties. One of the most important difficulties is the interior resistance of missile defense system's Kiirecik Radar Station and its usage in Turkey. Another important point is the question of control of Turkish National Security and Defense strategy. In that respect, the US government's smart power applications may be included in the establishment of the radar station. The EU has also been included in that strategy. This paper will argue smart power practices of the US, the EU and Turkey with reference to comparative practices of power politics and the case of Missile Defense System. In this way, a comprehensive and system-type assessment of possible responses and the change in relations between stakeholder states not only in the issue of a set-up of a Turkish radar station, but on a broader range of international "hard" security balance will be demonstrated.展开更多
Marine zooplankton responds sensitively to elevated seawater CO_2 concentration. However, the underlying physiological mechanisms have not been studied well. We therefore investigated the effects of elevated CO_2conce...Marine zooplankton responds sensitively to elevated seawater CO_2 concentration. However, the underlying physiological mechanisms have not been studied well. We therefore investigated the effects of elevated CO_2concentration(0.08%, 0.20%, 0.50% and 1.00%) on antioxidant defense components, as well as two detoxification enzymes of Calanus sinicus(copepod). The results showed that glutathione peroxidase(GPx) activity exposed to CO_2-acidified seawater was significantly stimulated while other antioxidant components, including glutathione-Stransferase(GST) activity, superoxide dismutase(SOD) activity decreased significantly with reduced glutathione(GSH) level and GSH/oxidized glutathione(GSSG) value. CO_2-acidified seawater exhibited stimulatory effects on adenosine triphosphatase(ATPase) activity and acetylcholinesterase(Ach E) activity was inhibited. Moreover, the results of principal component analysis indicated that 75.93% of the overall variance was explained by the first two principal components. The elevated CO_2 concentration may affect the metabolism and survivals of copepods through impacts these enzymes activities. Further studies are needed to focus on the synergistic effects of elevated CO_2 concentration and other environmental factors on copepods.展开更多
In this paper,the security problem for the multi-access edge computing(MEC)network is researched,and an intelligent immunity-based security defense system is proposed to identify the unauthorized mobile users and to p...In this paper,the security problem for the multi-access edge computing(MEC)network is researched,and an intelligent immunity-based security defense system is proposed to identify the unauthorized mobile users and to protect the security of whole system.In the proposed security defense system,the security is protected by the intelligent immunity through three functions,identification function,learning function,and regulation function,respectively.Meanwhile,a three process-based intelligent algorithm is proposed for the intelligent immunity system.Numerical simulations are given to prove the effeteness of the proposed approach.展开更多
The response of enzyme and non-enzymatic antioxidants of Mn hyperaccumuator, Polygonum hydropiper (P. hydropiper), to Mn stress was studied using hydroponics culture experiments to explore the mechanism of Mn tolera...The response of enzyme and non-enzymatic antioxidants of Mn hyperaccumuator, Polygonum hydropiper (P. hydropiper), to Mn stress was studied using hydroponics culture experiments to explore the mechanism of Mn tolerance in this species. Results showed that both chlorophyll and carotenoid contents significantly (p〈0.05) decreased with increasing Mn treatment levels (0, 0.5, 1, 2, 4, and 8 mg/L) in hydroponics. The concentrations of malondialdehyde (MDA) and hydrogen peroxide (H202) in the root and shoot of P hydropiper were accumulated under Mn stress. Meanwhile, the anti-oxidative functions of several important enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD) in plants were stimulated by Mn spike in leaves and roots, especially at low Mn stress; while sulfhydryl group (--SH) and glutathion (GSH) were likely involved in Mn detoxification ofP. hydropiper under high Mn stress.展开更多
In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting op...In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting optimization is how to choose the next BM which needs to be shot according to the previous engagements and results,thus maximizing the expected return of BMs killed or minimizing the cost of BMs penetration.Motivated by this,this study aims to determine an optimal shooting policy for a two-layer missile defense(TLMD)system.This paper considers a scenario in which the TLMD system wishes to shoot at a collection of BMs one at a time,and to maximize the return obtained from BMs killed before the system demise.To provide a policy analysis tool,this paper develops a general model for shooting decision-making,the shooting engagements can be described as a discounted reward Markov decision process.The index shooting policy is a strategy that can effectively balance the shooting returns and the risk that the defense mission fails,and the goal is to maximize the return obtained from BMs killed before the system demise.The numerical results show that the index policy is better than a range of competitors,especially the mean returns and the mean killing BM number.展开更多
Salinity is one of the most severe abiotic stresses for crop production.The present study investigates the salinityinduced modulation in growth indicators,morphology and movement of stomata,photosynthetic pigments,act...Salinity is one of the most severe abiotic stresses for crop production.The present study investigates the salinityinduced modulation in growth indicators,morphology and movement of stomata,photosynthetic pigments,activity of carbonic anhydrase as well as nitrate reductase,and antioxidant systems in two varieties of chickpea(Pusa-BG5023,and Pusa-BGD72).On 20^(th) day of sowing,plants were treated with varying levels of NaCl(0,50,100,150 and 200 mM)followed by sampling on 45 days of sowing.Recorded observations on both the varieties reveal that salt stress leads to a significant decline in growth,dry biomass,leaf area,photosynthetic pigments,protein content,stomatal behavior,cell viability,activity of nitrate reductase and carbonic anhydrase with the rise in the concentration of salt.However,quantitatively these changes were less in Pusa-BG5023 as compared to Pusa-BGD72.Furthermore,salinity-induced oxidative stress enhanced malondialdehyde content,superoxide radicals,foliar proline content,and the enzymatic activities of superoxide dismutase,catalase,and peroxidase.The variety Pusa-BGD72 was found more sensitive than Pusa-BG5023 to salt stress.Out of different graded concentrations(50,100,150 and 200 mM)of sodium chloride,50 mM was least toxic,and 200 mM was most damaging.The differential behavior of these two varieties measured in terms of stomatal behavior,cell viability,photosynthetic pigments,and antioxidant defense system can be used as prospective indicators for selection of chickpea plants for salt tolerance and sensitivity.展开更多
As a large amount of data needs to be processed and speed needs to be improved,edge computing with ultra-low latency and ultra-connectivity is emerging as a new paradigm.These changes can lead to new cyber risks,and s...As a large amount of data needs to be processed and speed needs to be improved,edge computing with ultra-low latency and ultra-connectivity is emerging as a new paradigm.These changes can lead to new cyber risks,and should therefore be considered for a security threat model.To this end,we constructed an edge system to study security in two directions,hardware and software.First,on the hardware side,we want to autonomically defend against hardware attacks such as side channel attacks by configuring field programmable gate array(FPGA)which is suitable for edge computing and identifying communication status to control the communication method according to priority.In addition,on the software side,data collected on the server performs end-to-end encryption via symmetric encryption keys.Also,we modeled autonomous defense systems on the server by using machine learning which targets to incoming and outgoing logs.Server log utilizes existing intrusion detection datasets that should be used in real-world environments.Server log was used to detect intrusion early by modeling an intrusion prevention system to identify behaviors that violate security policy,and to utilize the existing intrusion detection data set that should be used in a real environment.Through this,we designed an efficient autonomous defense system that can provide a stable system by detecting abnormal signals from the device and converting them to an effective method to control edge computing,and to detect and control abnormal intrusions on the server side.展开更多
:With the unceasing globalization development of MNCs' business and connnuous intensify in international competition, the managers of MNCs find that the strategy decisions they are faced on are becoming more compli...:With the unceasing globalization development of MNCs' business and connnuous intensify in international competition, the managers of MNCs find that the strategy decisions they are faced on are becoming more complicated, and they have deeply realized that the perception and defense of the international risk has the impact on their strategy decisions. The thesis, proceeding with analyzing and evaluating risk types in the course of enterprises developing in the international markets, based on the integration international risk perception model, utilizing relative theories and study thoughts of the corporate governance mechanisms, especially the relative studies on overseas enterprises' governance mechanisms, explores how to use the corporate governance mechanisms to build the defense system against international risks. Meanwhile, the thesis further discusses the risks our native enterprises have suffered from during the multinational operation in detail, explores its reasons and offers the defense measures of all sorts of risk.展开更多
Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,esp...Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.展开更多
Due to their advantages in flexibility,scalability,survivability,and cost-effectiveness,drone swarms have been increasingly used for reconnaissance tasks and have posed great challenges to their opponents on modern ba...Due to their advantages in flexibility,scalability,survivability,and cost-effectiveness,drone swarms have been increasingly used for reconnaissance tasks and have posed great challenges to their opponents on modern battlefields.This paper studies an optimization problem for deploying air defense systems against reconnaissance drone swarms.Given a set of available air defense systems,the problem determines the location of each air defense system in a predetermined region,such that the cost for enemy drones to pass through the region would be maximized.The cost is calculated based on a counterpart drone path planning problem.To solve this adversarial problem,we first propose an exact iterative search algorithm for small-size problem instances,and then propose an evolutionary framework that uses a specific encoding-decoding scheme for large-size problem instances.We implement the evolutionary framework with six popular evolutionary algorithms.Computational experiments on a set of different test instances validate the effectiveness of our approach for defending against reconnaissance drone swarms.展开更多
The blockchain cross-chain is a significant technology for inter-chain interconnection and value transfer among different blockchain networks.Cross-chain overcomes the“information island”problem of the closed blockc...The blockchain cross-chain is a significant technology for inter-chain interconnection and value transfer among different blockchain networks.Cross-chain overcomes the“information island”problem of the closed blockchain network and is increasingly applied to multiple critical areas such as finance and the internet of things(IoT).Blockchain can be divided into three main categories of blockchain networks:public blockchains,private blockchains,and consortium blockchains.However,there are differences in block structures,consensus mechanisms,and complex working mechanisms among heterogeneous blockchains.The fragility of the cross-chain system itself makes the cross-chain system face some potential security and privacy threats.This paper discusses security defects on the cross-chain implementation mechanism,and discusses the impact of the structural features of blockchain networks on cross-chain security.In terms of cross-chain intercommunication,a cross-chain attack can be divided into a multi-chain combination attack,native chain attack,and inter-chain attack diffusion.Then various security threats and attack paths faced by the cross-chain system are analyzed.At last,the corresponding security defense methods of cross-chain security threats and future research directions for cross-chain applications are put forward.展开更多
The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts ...The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.展开更多
The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference(EMI)shielding capabilities through a...The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference(EMI)shielding capabilities through absorption.Six fiber-reinforced epoxy composite panels,each with a different fabric material and stacking sequence,have been fabricated using a hand-layup vacuum bagging process.Two panels made of Kevlar and glass fibers,referred to as(K-NIJ)and(G-NIJ),have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA(9 mm×19 mm FMJ 124 g)test.Three panels,namely,a hybrid of Kevlar and glass(H-S),glass with ceramic particles(C-S),and glass with recycled rubber(R-S)have been impacted by the bullet at the center,while the fourth panel made of glass fiber(G-S)has been impacted at the side.EMI shielding properties have been measured in the X-band frequency range via the reflection-transmission method.Results indicate that four panels(K-NIJ,G-NIJ,H-S,and G-S)are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural integrity.However,under such conditions,these panels may experience localized delamination with variable severity.The EMI measurements reveal that the highest absorptivity observed is 88% for the KNIJ panel at 10.8 GHz,while all panels maintain an average absorptivity above 65%.All panels act as a lossy medium with a peak absorptivity at different frequencies,with K-NIJ and H-S panels demonstrating the highest absorptivity.In summary,the study results in the development of a novel,costeffective,multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding properties.The material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency;no bullet penetration or back face signature is observed,and it also demonstrates high EMI shielding absorption.Overall,the materials developed show great promise for various applications,including the military and defense.展开更多
The static and predictable characteristics of cyber systems give attackers an asymmetric advantage in gathering useful information and launching attacks.To reverse this asymmetric advantage,a new defense idea,called M...The static and predictable characteristics of cyber systems give attackers an asymmetric advantage in gathering useful information and launching attacks.To reverse this asymmetric advantage,a new defense idea,called Moving Target Defense(MTD),has been proposed to provide additional selectable measures to complement traditional defense.However,MTD is unable to defeat the sophisticated attacker with fingerprint tracking ability.To overcome this limitation,we go one step beyond and show that the combination of MTD and Deception-based Cyber Defense(DCD)can achieve higher performance than either of them.In particular,we first introduce and formalize a novel attacker model named Scan and Foothold Attack(SFA)based on cyber kill chain.Afterwards,we develop probabilistic models for SFA defenses to provide a deeper analysis of the theoretical effect under different defense strategies.These models quantify attack success probability and the probability that the attacker will be deceived under various conditions,such as the size of address space,and the number of hosts,attack analysis time.Finally,the experimental results show that the actual defense effect of each strategy almost perfectly follows its probabilistic model.Also,the defense strategy of combining address mutation and fingerprint camouflage can achieve a better defense effect than the single address mutation.展开更多
Background Necrotic enteritis(NE)is a major enteric disease in poultry,yet effective mitigation strategies remain elusive.Deoxycholic acid(DCA)and butyrate,two major metabolites derived from the intestinal microbiota,...Background Necrotic enteritis(NE)is a major enteric disease in poultry,yet effective mitigation strategies remain elusive.Deoxycholic acid(DCA)and butyrate,two major metabolites derived from the intestinal microbiota,have independently been shown to induce host defense peptide(HDP)synthesis.However,the potential synergy between these two compounds remains unexplored.Methods To investigate the possible synergistic effect between DCA and butyrate in regulating HDP synthesis and barrier function,we treated chicken HD11 macrophage cells and jejunal explants with DCA and sodium butyrate(NaB),either individually or in combination,for 24 h.Subsequently,we performed RNA isolation and reverse transcrip-tion-quantitative PCR to analyze HDP genes as well as the major genes associated with barrier function.To further determine the synergy between DCA and NaB in enhancing NE resistance,we conducted two independent trials with Cobb broiler chicks.In each trial,the diet was supplemented with DCA or NaB on the day-of-hatch,followed by NE induction through sequential challenges with Eimeria maxima and Clostridium perfringens on d 10 and 14,respectively.We recorded animal mortality after infection and assessed intestinal lesions on d 17.The impact of DCA and NaB on the microbiota in the ileum and cecum was evaluated through bacterial 16S rRNA gene sequencing.Results We found that the combination of DCA and NaB synergistically induced multiple HDP genes in both chicken HD11 cells and jejunal explants.Additionally,the gene for claudin-1,a major tight junction protein,also exhibited synergistic induction in response to DCA and NaB.Furthermore,dietary supplementation with a combination of 0.75 g/kg DCA and 1 g/kg NaB led to a significant improvement in animal survival and a reduction in intestinal lesions compared to either compound alone in a chicken model of NE.Notably,the cecal microbiota of NE-infected chickens showed a marked decrease in SCFA-producing bacteria such as Bacteroides,Faecalibacterium,and Cuneatibacter,with lactobacilli becoming the most dominant species.However,supplementation with DCA and NaB largely restored the intestinal microbiota to healthy levels.Conclusions DCA synergizes with NaB to induce HDP and claudin-1 expression and enhance NE resistance,with potential for further development as cost-effective antibiotic alternatives.展开更多
文摘Arsenic(As)contaminated food chains have emerged as a serious public concern for humans and animals and are known to affect the cultivation of edible crops throughout the world.Therefore,the present study was designed to investigate the individual as well as the combined effects of exogenous silicon(Si)and sodium nitroprusside(SNP),a nitric oxide(NO)donor,on plant growth,metabolites,and antioxidant defense systems of radish(Raphanus sativus L.)plants under three different concentrations of As stress,i.e.,0.3,0.5,and 0.7 mM in a pot experiment.The results showed that As stress reduced the growth parameters of radish plants by increasing the level of oxidative stress markers,i.e.,malondialdehyde and hydrogen peroxide.However,foliar application of Si(2 mM)and pretreatment with SNP(100μM)alone as well as in combination with Si improved the plant growth parameters,i.e.,root length,fresh and dry weight of plants under As stress.Furthermore,As stress also reduced protein,and metabolites contents(flavonoids,phenolic and anthocyanin).Activities of antioxidative enzymes such as catalase(CAT),ascorbate peroxidase(APX),guaiacol peroxidase(POD),and polyphenol oxidase(PPO),as well as the content of non-enzymatic antioxidants(glutathione and ascorbic acid)decreased under As stress.In most of the parameters in radish,As III concentration showed maximum reduction,as compared to As I and II concentrations.However,the individual and combined application of Si and NO significantly alleviated the As-mediated oxidative stress in radish plants by increasing the protein,and metabolites content.Enhancement in the activities of CAT,APX,POD and PPO enzymes were recorded.Contents of glutathione and ascorbic acid were also enhanced in response to co-application of Si and NO under As stress.Results obtained were more pronounced when Si and NO were applied in combination under As stress,as compared to their individual application.In short,the current study highlights that Si and NO synergistically regulate plant growth through lowering the As-mediated oxidative stress by upregulating the metabolites content,activity of antioxidative enzymes and non-enzymatic antioxidants in radish plants.
基金supported by the National Natural Science Foundation of China(61272011)
文摘In order to solve the problem that the ripple-effect analy- sis for the operational architecture of air defense systems (OAADS) is hardly described in quantity with previous modeling approaches, a supernetwork modeling approach for the OAADS is put for- ward by extending granular computing. Based on that operational units and links are equal to different information granularities, the supernetwork framework of the OAADS is constructed as a “four- network within two-layer” structure by forming dynamic operating coalitions, and measuring indexes of the ripple-effect analysis for the OAADS are given combining with Laplace spectral radius. In this framework, via analyzing multidimensional attributes which inherit relations between operational units in different granular scales, an extended granular computing is put forward integrating with a topological structure. Then the operation process within the supernetwork framework, including transformation relations be- tween two layers in the vertical view and mapping relations among functional networks in the horizontal view, is studied in quantity. As the application case shows, comparing with previous modeling approaches, the supernetwork model can validate and analyze the operation mechanism in the air defense architecture, and the ripple-effect analysis can be used to confirm the key operational unit with micro and macro viewpoints.
基金supported by the National Natural Science Foundation of China (No. 20777040)the Hi-TechResearch and Development Program (863) of China (No.2007AA061201).
文摘Under the indoor simulant conditions, toxic effects of crude-oil-contaminated soil which was put into aquatic environment on the young fishes Carassius auratus and their hepatic antioxidant system after a 20-d exposure were investigated. Results showed that the relationship between the mortality of C. auratus and the exposed doses could be divided into 3 phases: fishes exposed to the low dose groups (0.5-5.0 g/L) were dead due to the ingestion of crude-oil-contaminated soils in aquatic environment; at the medium dose groups (5.0-25.0 g/L) fishes were dead due to the penetration of toxic substances; at the high dose groups (25.0-50.0 g/L) fishes were dead due to environmental stress. The highest mortality and death speed were found in the 1.0 g/L dose group, and the death speed was sharply increased in the 50.0 g/L dose group in the late phase of exposure. The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the content of malaondialdehyde (MDA) in the hepatic tissues of C. auratus were induced significantly. The activity of SOD was increased and then decreased. It was significantly inhibited in the 50.0 g/L dose group. The activity of CAT was highly induced, and restored to a level which is little more than the control when the exposed doses exceeded 10.0 g/L. The activity of GST was the most sensitive, it was significantly induced in all dose groups, and the highest elevation was up to 6 times in the 0.5 g/L dose group comparing with the control. The MDA content was significantly elevated in the 50.0 g/L dose group, and the changes of the MDA content were opposite with the changes of GST activity.
基金Sponsored by Jiangsu Planned Project for Postdoctoral (0901014B)
文摘The fire distribution can be divided into weapon assignment and firing time scheduling. The criterion of weapon allocation is that a target with greater threat has higher priority. And the criterion of firing time scheduling is that a target can be damaged with the expected probability before a specific time. A fire distribution scheme and a program for the integrated missile-gun air defense system based on a criterion of earlier damage were presented. An example was taken to illustrate its effectiveness.
文摘Various application domains require the integration of distributed real-time or near-real-time systems with non-real-time systems.Smart cities,smart homes,ambient intelligent systems,or network-centric defense systems are among these application domains.Data Distribution Service(DDS)is a communication mechanism based on Data-Centric Publish-Subscribe(DCPS)model.It is used for distributed systems with real-time operational constraints.Java Message Service(JMS)is a messaging standard for enterprise systems using Service Oriented Architecture(SOA)for non-real-time operations.JMS allows Java programs to exchange messages in a loosely coupled fashion.JMS also supports sending and receiving messages using a messaging queue and a publish-subscribe interface.In this article,we propose an architecture enabling the automated integration of distributed real-time and non-real-time systems.We test our proposed architecture using a distributed Command,Control,Communications,Computers,and Intelligence(C4I)system.The system has DDS-based real-time Combat Management System components deployed to naval warships,and SOA-based non-real-time Command and Control components used at headquarters.The proposed solution enables the exchange of data between these two systems efficiently.We compare the proposed solution with a similar study.Our solution is superior in terms of automation support,ease of implementation,scalability,and performance.
文摘The concept of smart power requires to combine soft and hard power. Thus, smart power is a new approach for the US politics towards the Middle East. As a consequence of smart power politics of the US, some newly members of the EU and Turkey has become a part of missile defense system. This is a significant indicator of usage of smart power for the EU members and Turkey. The security policies and practices of the US disclose a necessity for straight allies. For this reason, the relationship between the US, the EU and Turkey may be conceptualize with reference to the concept of smart power. In the case of Missile Defense System, Turkey has agreed to be a participant of this system after signing an agreement with the US. After that, Turkish government has confronted with some interior and exterior political difficulties. One of the most important difficulties is the interior resistance of missile defense system's Kiirecik Radar Station and its usage in Turkey. Another important point is the question of control of Turkish National Security and Defense strategy. In that respect, the US government's smart power applications may be included in the establishment of the radar station. The EU has also been included in that strategy. This paper will argue smart power practices of the US, the EU and Turkey with reference to comparative practices of power politics and the case of Missile Defense System. In this way, a comprehensive and system-type assessment of possible responses and the change in relations between stakeholder states not only in the issue of a set-up of a Turkish radar station, but on a broader range of international "hard" security balance will be demonstrated.
文摘Marine zooplankton responds sensitively to elevated seawater CO_2 concentration. However, the underlying physiological mechanisms have not been studied well. We therefore investigated the effects of elevated CO_2concentration(0.08%, 0.20%, 0.50% and 1.00%) on antioxidant defense components, as well as two detoxification enzymes of Calanus sinicus(copepod). The results showed that glutathione peroxidase(GPx) activity exposed to CO_2-acidified seawater was significantly stimulated while other antioxidant components, including glutathione-Stransferase(GST) activity, superoxide dismutase(SOD) activity decreased significantly with reduced glutathione(GSH) level and GSH/oxidized glutathione(GSSG) value. CO_2-acidified seawater exhibited stimulatory effects on adenosine triphosphatase(ATPase) activity and acetylcholinesterase(Ach E) activity was inhibited. Moreover, the results of principal component analysis indicated that 75.93% of the overall variance was explained by the first two principal components. The elevated CO_2 concentration may affect the metabolism and survivals of copepods through impacts these enzymes activities. Further studies are needed to focus on the synergistic effects of elevated CO_2 concentration and other environmental factors on copepods.
基金This work was supported by National Natural Science Foundation of China(No.61971026)the Fundamental Research Funds for the Central Universities(No.FRF-TP-18-008A3).
文摘In this paper,the security problem for the multi-access edge computing(MEC)network is researched,and an intelligent immunity-based security defense system is proposed to identify the unauthorized mobile users and to protect the security of whole system.In the proposed security defense system,the security is protected by the intelligent immunity through three functions,identification function,learning function,and regulation function,respectively.Meanwhile,a three process-based intelligent algorithm is proposed for the intelligent immunity system.Numerical simulations are given to prove the effeteness of the proposed approach.
基金Project(41161057)supported by the National Natural Science Foundation of ChinaProject(Guikezhuan 14122008-2)supported by Guangxi Provincial Science and Technology Development,China+2 种基金Project(2014GXNSFAA118303)supported by the Natural Science Foundation of Guangxi Province,ChinaProjects(YRHJ15K002,YRHJ15Z026)supported by Key Laboratory of Karst Ecology and Environment Change of Guangxi Normal University,ChinaProject(2016JJ6135)supported by the Natural Science Foundation of Hunan Province,China
文摘The response of enzyme and non-enzymatic antioxidants of Mn hyperaccumuator, Polygonum hydropiper (P. hydropiper), to Mn stress was studied using hydroponics culture experiments to explore the mechanism of Mn tolerance in this species. Results showed that both chlorophyll and carotenoid contents significantly (p〈0.05) decreased with increasing Mn treatment levels (0, 0.5, 1, 2, 4, and 8 mg/L) in hydroponics. The concentrations of malondialdehyde (MDA) and hydrogen peroxide (H202) in the root and shoot of P hydropiper were accumulated under Mn stress. Meanwhile, the anti-oxidative functions of several important enzymes, including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD) in plants were stimulated by Mn spike in leaves and roots, especially at low Mn stress; while sulfhydryl group (--SH) and glutathion (GSH) were likely involved in Mn detoxification ofP. hydropiper under high Mn stress.
基金supported by the National Natural Science Foundation of China(7170120971771216)+1 种基金Shaanxi Natural Science Foundation(2019JQ-250)China Post-doctoral Fund(2019M653962)
文摘In order to cope with the increasing threat of the ballistic missile(BM)in a shorter reaction time,the shooting policy of the layered defense system needs to be optimized.The main decisionmaking problem of shooting optimization is how to choose the next BM which needs to be shot according to the previous engagements and results,thus maximizing the expected return of BMs killed or minimizing the cost of BMs penetration.Motivated by this,this study aims to determine an optimal shooting policy for a two-layer missile defense(TLMD)system.This paper considers a scenario in which the TLMD system wishes to shoot at a collection of BMs one at a time,and to maximize the return obtained from BMs killed before the system demise.To provide a policy analysis tool,this paper develops a general model for shooting decision-making,the shooting engagements can be described as a discounted reward Markov decision process.The index shooting policy is a strategy that can effectively balance the shooting returns and the risk that the defense mission fails,and the goal is to maximize the return obtained from BMs killed before the system demise.The numerical results show that the index policy is better than a range of competitors,especially the mean returns and the mean killing BM number.
文摘Salinity is one of the most severe abiotic stresses for crop production.The present study investigates the salinityinduced modulation in growth indicators,morphology and movement of stomata,photosynthetic pigments,activity of carbonic anhydrase as well as nitrate reductase,and antioxidant systems in two varieties of chickpea(Pusa-BG5023,and Pusa-BGD72).On 20^(th) day of sowing,plants were treated with varying levels of NaCl(0,50,100,150 and 200 mM)followed by sampling on 45 days of sowing.Recorded observations on both the varieties reveal that salt stress leads to a significant decline in growth,dry biomass,leaf area,photosynthetic pigments,protein content,stomatal behavior,cell viability,activity of nitrate reductase and carbonic anhydrase with the rise in the concentration of salt.However,quantitatively these changes were less in Pusa-BG5023 as compared to Pusa-BGD72.Furthermore,salinity-induced oxidative stress enhanced malondialdehyde content,superoxide radicals,foliar proline content,and the enzymatic activities of superoxide dismutase,catalase,and peroxidase.The variety Pusa-BGD72 was found more sensitive than Pusa-BG5023 to salt stress.Out of different graded concentrations(50,100,150 and 200 mM)of sodium chloride,50 mM was least toxic,and 200 mM was most damaging.The differential behavior of these two varieties measured in terms of stomatal behavior,cell viability,photosynthetic pigments,and antioxidant defense system can be used as prospective indicators for selection of chickpea plants for salt tolerance and sensitivity.
基金This research was funded by Korea Environmental Industry&Technology Institute(KEITI),Grant Number RE202101551and The APC was funded by Ministry of Environment(ME).
文摘As a large amount of data needs to be processed and speed needs to be improved,edge computing with ultra-low latency and ultra-connectivity is emerging as a new paradigm.These changes can lead to new cyber risks,and should therefore be considered for a security threat model.To this end,we constructed an edge system to study security in two directions,hardware and software.First,on the hardware side,we want to autonomically defend against hardware attacks such as side channel attacks by configuring field programmable gate array(FPGA)which is suitable for edge computing and identifying communication status to control the communication method according to priority.In addition,on the software side,data collected on the server performs end-to-end encryption via symmetric encryption keys.Also,we modeled autonomous defense systems on the server by using machine learning which targets to incoming and outgoing logs.Server log utilizes existing intrusion detection datasets that should be used in real-world environments.Server log was used to detect intrusion early by modeling an intrusion prevention system to identify behaviors that violate security policy,and to utilize the existing intrusion detection data set that should be used in a real environment.Through this,we designed an efficient autonomous defense system that can provide a stable system by detecting abnormal signals from the device and converting them to an effective method to control edge computing,and to detect and control abnormal intrusions on the server side.
基金This research was supported by the National Social Science Foundation of China, and its approval number is 03CJY011
文摘:With the unceasing globalization development of MNCs' business and connnuous intensify in international competition, the managers of MNCs find that the strategy decisions they are faced on are becoming more complicated, and they have deeply realized that the perception and defense of the international risk has the impact on their strategy decisions. The thesis, proceeding with analyzing and evaluating risk types in the course of enterprises developing in the international markets, based on the integration international risk perception model, utilizing relative theories and study thoughts of the corporate governance mechanisms, especially the relative studies on overseas enterprises' governance mechanisms, explores how to use the corporate governance mechanisms to build the defense system against international risks. Meanwhile, the thesis further discusses the risks our native enterprises have suffered from during the multinational operation in detail, explores its reasons and offers the defense measures of all sorts of risk.
基金supported by the National Natural Science Foundation of China(Grant No.32061143012 to A.Z.,32101352 to X.H.).
文摘Marine ecosystems are facing escalating environmental fluctuations owing to climate change and human activities,imposing pressures on marine species.To withstand recurring environmental challenges,marine organisms,especially benthic species lacking behavioral choices to select optimal habitats,have to utilize well-established strategies such as the antioxidant defense system(ADS)to ensure their survival.Therefore,understanding of the mechanisms governing the ADS-based response is essential for gaining insights into adaptive strategies for managing environmental challenges.Here we conducted a com-parative analysis of the physiological and transcriptional responses based on the ADS during two rounds of'hypersalinity-recovery'challenges in two model congeneric invasive ascidians,Ciona robusta and C.savignyi.Our results demonstrated that C.savignyi exhibited higher tolerance and resistance to salinity stresses at the physiological level,while C.robusta demonstrated heightened responses at the transcriptional level.We observed distinct transcriptional responses,particularly in the utilization of two superoxide dismutase(SOD)isoforms.Both Ciona species developed physiological stress memory with elevated total SOD(T-SOD)and glutathione(GSH)responses,while only C.robusta demonstrated transcriptional stress memory.The regulatory distinctions within the Nrf2-Keap1 signalling pathway likely explain the formation disparity of transcriptional stress memory between both Ciona species.These findings support the'context-dependent stress memory hypothesis',emphasizing the emergence of species-specific stress memory at diverse regulatory levels in response to recurrent environmental challenges.Our results enhance our understanding of the mechanisms of environmental challenge manage-ment in marine species,particularly those related to the ADS.
基金supported by the National Natural Science Foundation of China(No.61872123)the Natural Science Foundation of Zhejiang Province(No.LR20F030002).
文摘Due to their advantages in flexibility,scalability,survivability,and cost-effectiveness,drone swarms have been increasingly used for reconnaissance tasks and have posed great challenges to their opponents on modern battlefields.This paper studies an optimization problem for deploying air defense systems against reconnaissance drone swarms.Given a set of available air defense systems,the problem determines the location of each air defense system in a predetermined region,such that the cost for enemy drones to pass through the region would be maximized.The cost is calculated based on a counterpart drone path planning problem.To solve this adversarial problem,we first propose an exact iterative search algorithm for small-size problem instances,and then propose an evolutionary framework that uses a specific encoding-decoding scheme for large-size problem instances.We implement the evolutionary framework with six popular evolutionary algorithms.Computational experiments on a set of different test instances validate the effectiveness of our approach for defending against reconnaissance drone swarms.
基金supported by the Beijing Natural Science Foundation(4212008)the National Natural Science Foundation of China(62272031)+2 种基金the Open Foundation of Information Security Evaluation Center of Civil Aviation,Civil Aviation University of China(ISECCA-202101)Guangxi Key Laboratory of Cryptography and Information Security(GCIS201915)supported in part by the National Natural Science Foundation of China(U21A20463,U22B2027)。
文摘The blockchain cross-chain is a significant technology for inter-chain interconnection and value transfer among different blockchain networks.Cross-chain overcomes the“information island”problem of the closed blockchain network and is increasingly applied to multiple critical areas such as finance and the internet of things(IoT).Blockchain can be divided into three main categories of blockchain networks:public blockchains,private blockchains,and consortium blockchains.However,there are differences in block structures,consensus mechanisms,and complex working mechanisms among heterogeneous blockchains.The fragility of the cross-chain system itself makes the cross-chain system face some potential security and privacy threats.This paper discusses security defects on the cross-chain implementation mechanism,and discusses the impact of the structural features of blockchain networks on cross-chain security.In terms of cross-chain intercommunication,a cross-chain attack can be divided into a multi-chain combination attack,native chain attack,and inter-chain attack diffusion.Then various security threats and attack paths faced by the cross-chain system are analyzed.At last,the corresponding security defense methods of cross-chain security threats and future research directions for cross-chain applications are put forward.
基金funded by the National Natural Science Foundation of China (Nos. 31970427 and 32270526 to WL)。
文摘The interactions between avian brood parasites and their hosts provide an informative and easy-to-handle system for studying coevolution.Avian brood parasitism reduces the reproductive success of hosts,and thus,hosts have evolved anti-parasitic strategies,such as rejecting parasitic eggs and adopting aggressive nest defense strategies,to avoid the cost brought on by brood parasitism.To test whether host anti-parasitic strategies are adjusted with the risk of being parasitized when the breeding seasons of brood parasites and hosts are not synchronous,we conducted a field experiment assessing nest defense and egg recognition behaviors of the Isabelline Shrike(Lanius isabellinus),a host of the Common Cuckoo(Cuculus canorus).In the local area,the host Isabelline Shrike begins to breed in April,whereas the summer migratory Common Cuckoo migrates to the local area in May and begins to lay parasitic eggs.Results showed that nest defense behaviors of the Isabelline Shrike increases significantly after cuckoo arrival,showing higher aggressiveness to cuckoo dummies,with no significant difference in attack rates among cuckoo,sparrowhawk and dove dummies,but their egg rejection did not change significantly.These results imply that Isabelline Shrikes may adjust their nest defense behavior,but not egg rejection behavior,with seasonality.
基金the generous support from the Deanship of Research-Jordan University of Science and Technology,IrbidJordan(Grant number 318/2021)。
文摘The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference(EMI)shielding capabilities through absorption.Six fiber-reinforced epoxy composite panels,each with a different fabric material and stacking sequence,have been fabricated using a hand-layup vacuum bagging process.Two panels made of Kevlar and glass fibers,referred to as(K-NIJ)and(G-NIJ),have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA(9 mm×19 mm FMJ 124 g)test.Three panels,namely,a hybrid of Kevlar and glass(H-S),glass with ceramic particles(C-S),and glass with recycled rubber(R-S)have been impacted by the bullet at the center,while the fourth panel made of glass fiber(G-S)has been impacted at the side.EMI shielding properties have been measured in the X-band frequency range via the reflection-transmission method.Results indicate that four panels(K-NIJ,G-NIJ,H-S,and G-S)are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural integrity.However,under such conditions,these panels may experience localized delamination with variable severity.The EMI measurements reveal that the highest absorptivity observed is 88% for the KNIJ panel at 10.8 GHz,while all panels maintain an average absorptivity above 65%.All panels act as a lossy medium with a peak absorptivity at different frequencies,with K-NIJ and H-S panels demonstrating the highest absorptivity.In summary,the study results in the development of a novel,costeffective,multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding properties.The material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency;no bullet penetration or back face signature is observed,and it also demonstrates high EMI shielding absorption.Overall,the materials developed show great promise for various applications,including the military and defense.
基金supported by the National Key Research and Development Program of China(No.2016YFB0800601)the Key Program of NSFC-Tongyong Union Foundation(No.U1636209)+1 种基金the National Natural Science Foundation of China(61602358)the Key Research and Development Programs of Shaanxi(No.2019ZDLGY13-04,No.2019ZDLGY13-07)。
文摘The static and predictable characteristics of cyber systems give attackers an asymmetric advantage in gathering useful information and launching attacks.To reverse this asymmetric advantage,a new defense idea,called Moving Target Defense(MTD),has been proposed to provide additional selectable measures to complement traditional defense.However,MTD is unable to defeat the sophisticated attacker with fingerprint tracking ability.To overcome this limitation,we go one step beyond and show that the combination of MTD and Deception-based Cyber Defense(DCD)can achieve higher performance than either of them.In particular,we first introduce and formalize a novel attacker model named Scan and Foothold Attack(SFA)based on cyber kill chain.Afterwards,we develop probabilistic models for SFA defenses to provide a deeper analysis of the theoretical effect under different defense strategies.These models quantify attack success probability and the probability that the attacker will be deceived under various conditions,such as the size of address space,and the number of hosts,attack analysis time.Finally,the experimental results show that the actual defense effect of each strategy almost perfectly follows its probabilistic model.Also,the defense strategy of combining address mutation and fingerprint camouflage can achieve a better defense effect than the single address mutation.
基金supported by the USDA National Institute of Food and Agriculture grants (2020-67016-31619 and 2023-67015-39095)the Ralph F. and Leila W. Boulware Endowment Fund+1 种基金Oklahoma Agricultural Experiment Station Project H-3112supported by a USDA National Institute of Food and Agriculture Predoctoral Fellowship grant (2021-67034-35184)
文摘Background Necrotic enteritis(NE)is a major enteric disease in poultry,yet effective mitigation strategies remain elusive.Deoxycholic acid(DCA)and butyrate,two major metabolites derived from the intestinal microbiota,have independently been shown to induce host defense peptide(HDP)synthesis.However,the potential synergy between these two compounds remains unexplored.Methods To investigate the possible synergistic effect between DCA and butyrate in regulating HDP synthesis and barrier function,we treated chicken HD11 macrophage cells and jejunal explants with DCA and sodium butyrate(NaB),either individually or in combination,for 24 h.Subsequently,we performed RNA isolation and reverse transcrip-tion-quantitative PCR to analyze HDP genes as well as the major genes associated with barrier function.To further determine the synergy between DCA and NaB in enhancing NE resistance,we conducted two independent trials with Cobb broiler chicks.In each trial,the diet was supplemented with DCA or NaB on the day-of-hatch,followed by NE induction through sequential challenges with Eimeria maxima and Clostridium perfringens on d 10 and 14,respectively.We recorded animal mortality after infection and assessed intestinal lesions on d 17.The impact of DCA and NaB on the microbiota in the ileum and cecum was evaluated through bacterial 16S rRNA gene sequencing.Results We found that the combination of DCA and NaB synergistically induced multiple HDP genes in both chicken HD11 cells and jejunal explants.Additionally,the gene for claudin-1,a major tight junction protein,also exhibited synergistic induction in response to DCA and NaB.Furthermore,dietary supplementation with a combination of 0.75 g/kg DCA and 1 g/kg NaB led to a significant improvement in animal survival and a reduction in intestinal lesions compared to either compound alone in a chicken model of NE.Notably,the cecal microbiota of NE-infected chickens showed a marked decrease in SCFA-producing bacteria such as Bacteroides,Faecalibacterium,and Cuneatibacter,with lactobacilli becoming the most dominant species.However,supplementation with DCA and NaB largely restored the intestinal microbiota to healthy levels.Conclusions DCA synergizes with NaB to induce HDP and claudin-1 expression and enhance NE resistance,with potential for further development as cost-effective antibiotic alternatives.