Native herbivory may be detrimental to plant fitness and thus can contribute a biotic resistance to exotic plant invasion.Eupatorium adenophorum,a non-native species,has formed dense monocultures in many southern Prov...Native herbivory may be detrimental to plant fitness and thus can contribute a biotic resistance to exotic plant invasion.Eupatorium adenophorum,a non-native species,has formed dense monocultures in many southern Provinces of China.Because several native generalist insects feed on E.adenophorum,we evaluated whether the lower level of induced defences and greater compensatory growth contributed to successful invasion of E.adenophorum by comparison with a native congener E.heterophyllum.Early events in the jasmonic acid cascade and chlorophyll fluorescence,non-target metabolomic profiles and recovery in biomass compensation of E.adenophorum and its native congener E.heterophyllum were measured during mechanical wounding and herbivory by the generalist insect Helicoverpa armigera.Mechanical and simulated chewing damage immediately initiated defences in the two species.However,E.heterophyllum was more sensitive to tissue loss,and it produced more metabolic defensive compounds than invasive E.adenophorum.Although H.armigera feeding amplified the effects of mechanical wounding on defence induction,the biomass of E.adenophorum was only weakly affected,as its higher compensatory growth could offset the biomass loss and metabolic cost.Overall,our results suggest that H.armigera herbivory and mechanical wounding could induce different physiological responses,and are often specific to invasive E.adenophorum and native E.heterophyllum.Moreover,lower metabolic defences and higher compensation growth may contribute to the invasion success of E.adenophorum.展开更多
The seedling phase represents an initial and critical stage for the establishment of individuals in the ecosystem.During this stage,specialized metabolites contribute to survival;however,studies analyzing the presence...The seedling phase represents an initial and critical stage for the establishment of individuals in the ecosystem.During this stage,specialized metabolites contribute to survival;however,studies analyzing the presence of these molecules and the reasons for their production and accumulation are still scarce.Annonaceae is a botanical family recognized for the chemodiversity of its secondary metabolites;nearly 1000 alkaloids have been reported in approximately 150 adult specimens.The aim of this studywas to determinewhether alkaloid biosynthesis in Annonaceae is expressed from early stages.For this purpose,Annona macroprophyllata,Annona muricata,Annona purpurea,and Annona reticulata seedlings,tropical Annonaceae with a history of alkaloids in adult stages,were studied.Alkaloidswere extracted using the selective acid-basemethod fromroots,stems,and leaves of seedlings with one to two pairs of leaves.The chemical composition analysis was performed using gas chromatography coupled to a mass spectrum.The identity of molecules was confirmed with standards and bibliographical references.Alkaloids were detected in the tissues of all species,and 28 of these metabolites were identified,92%with a benzylisoquinoline structure.Many of them have reports of various biological activities.These alkaloids are not derived fromthe mother plant,as no alkaloidswere found in the seeds.Nine,nine,eight,and twenty alkaloids were detected in seedlings of A.macroprophyllata,A.muricata,A.reticulata,and A.purpurea,respectively.The roots of all species are the organs with the most alkaloids(both in abundance and chemical richness).In conclusion,alkaloid metabolism is expressed during the early development stages in Annonaceae and could be associated with the chemical defense theory.These findings enhance our understanding of how seedlings use chemical strategies to adapt to their environment.They also demonstrate that seedlings can produce active compounds,even when grown under controlled conditions.展开更多
The study aimed to develop a customized Data Governance Maturity Model (DGMM) for the Ministry of Defence (MoD) in Kenya to address data governance challenges in military settings. Current frameworks lack specific req...The study aimed to develop a customized Data Governance Maturity Model (DGMM) for the Ministry of Defence (MoD) in Kenya to address data governance challenges in military settings. Current frameworks lack specific requirements for the defence industry. The model uses Key Performance Indicators (KPIs) to enhance data governance procedures. Design Science Research guided the study, using qualitative and quantitative methods to gather data from MoD personnel. Major deficiencies were found in data integration, quality control, and adherence to data security regulations. The DGMM helps the MOD improve personnel, procedures, technology, and organizational elements related to data management. The model was tested against ISO/IEC 38500 and recommended for use in other government sectors with similar data governance issues. The DGMM has the potential to enhance data management efficiency, security, and compliance in the MOD and guide further research in military data governance.展开更多
The liver is considered a vital organ and is the hub for multiple chemical functions,such as intermediary metabolism and the detoxification of ingested toxins,which are essential for the preservation of life,hence,the...The liver is considered a vital organ and is the hub for multiple chemical functions,such as intermediary metabolism and the detoxification of ingested toxins,which are essential for the preservation of life,hence,the origin or the word“liver”.The liver has enormous,highly diversified catalytic potential.This enormous catalytic potential generates massive oxidative stress,which is important for the functions of the liver but is detrimental to the viability of the liver.The liver receives approximately 80%of its blood supply from the portal vein,which brings less saturated blood from the gastrointestinal tract.Hepatocytes operate in a relatively hypoxic microenvironment due to this portal inflow.The development of this hypoxic microenvironment of the liver is an important evolutionary adaptation for its detoxification function that is not recognized in the literature as a defence mechanism against the oxidative stress generated during the detoxification process.This review describes liver function in relation to its oxidative catalytic potential and the oxidative stress generated by it as well as the evolutionary defence mechanisms present in the liver against this oxidative stress to provide new insights into liver function.展开更多
The defence sector is now at an advanced level,catering to the global scenario,and countries also invest heavily in research and development.Countries around the world have spent a lot of money on research and develop...The defence sector is now at an advanced level,catering to the global scenario,and countries also invest heavily in research and development.Countries around the world have spent a lot of money on research and development over the years in order to stay ahead of their competitors.Lightweight materials are critical in defence applications because they allow components to be lighter without sacrificing strength.This review provides an overview of the research related to defence applications.The book provides comprehensive details on current trends in the application of lightweight materials in defence.This review also includes historical and current perspectives on defence technologies.It discusses uses of lightweight materials such as metal matrix composites,polymer composites,ceramic matrix composites,fiber composites in defence sectors Finally,the review paper also emphasizes future military applications of lightweight materials.展开更多
Carbon-based composites, including carbon reinforced composites and carbon-matrix composites, in defence technologies have raised a lot of attention due to its significant physical capabilities, superior thermal and m...Carbon-based composites, including carbon reinforced composites and carbon-matrix composites, in defence technologies have raised a lot of attention due to its significant physical capabilities, superior thermal and mechanical stability, and its eco-friendly nature. Carbon-based composite which incorporating with various carbonaceous materials such as coke, char, black carbon, activated carbon, carbon fibre and other carbon nanomaterials (carbon nanotubes, carbon nanofibres, graphene and graphite) are the greatest viable option for the development of advanced defence technologies. In this review article the characteristics of carbon-based materials and its composites are discussed for their distinct application in defence sectors;aeronautics, maritime, automotive, electronics, energy storage, electromagnetic interference (EMI) shielding and structures. The origin of carbonaceous materials and its production techniques were discussed. Carbon-based composites have a promising future in defence technology, particularly in chemical sensors, drug delivery agents, radar technologies, and nanocomposites due to their low cost, easy availability, flexibility in design and processing.展开更多
The gastrointestinal innate and adaptive immune system continuously faces the challenge of potent stimuli from the commensal microflora and food constituents. These local immune responses require a tight control, the ...The gastrointestinal innate and adaptive immune system continuously faces the challenge of potent stimuli from the commensal microflora and food constituents. These local immune responses require a tight control, the outcome of which is in most cases the induction of tolerance. Local T cell immunity is an important compartment of the specif ic intestinal immune system. T cell reactivity is programmed during the initial stage of its activation by professional presenting cells. Mucosal dendritic cells (DCs) are assumed to play key roles in regulating immune responses in the antigen-rich gastrointestinal environment. Mucosal DCs are a heterogeneous population that can either initiate (innate and adaptive) immune responses, or control intestinal inflammation and maintain tolerance. Defects in this regulation are supposed to lead to the two major forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC). This review will discuss the emerging role of mucosal DCs in regulating intestinal inflammation and immune responses.展开更多
Aim: To find out whether the response of testicular oxidative stress parameters to hexachlorocyclohexane (HCH) is species specific. Methods: In rats and mice (n=5 in each group), HCH was administered at a dose of 20 m...Aim: To find out whether the response of testicular oxidative stress parameters to hexachlorocyclohexane (HCH) is species specific. Methods: In rats and mice (n=5 in each group), HCH was administered at a dose of 20 mg/kg/day intraperitoneally for 30 days in 0.1 ml of refined groundnut oil. The control groups received equal volume of the vehicle. Animals were sacrificed 24 hours after the last injection and various oxidative stress parameters were measured immediately. Results: The level of both endogenous as well as FeSO_4 and ascorbic acid-stimulated lipid peroxidation was increased significantly in the HCH-treated rats, whereas the pattern was just the reverse in case of mice. Although the level of H_2O_2 content increased in response to HCH in both groups, a totally different trend was observed for the activity of the principal H_2O_2-metabolising enzyme, catalase. In case of rats, a significant decline in the activity of catalase was recorded in response to HCH whereas a sharp augmentation in the enzyme activity was noticed in mice. Similarly, the decreased activity of superoxide dismutase observed in rats remained unaltered in mice. Conclusion: HCH induces oxidative stress in the testis of both rats and mice. However, the pattern of response of testicular oxidative stress parameters seems to be species specific.展开更多
As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and...As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds,primarily fl avonoids.Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level.During the early stages of development,non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics.At later developmental stages,and during secondary wall thickening,phenolics are transferred to the cell walls of the trichomes.Due to the diff use deposition of phenolics in the cell walls,trichomes provide protection against UV-B radiation by behaving as optical fi lters,screening out wavelengths that could damage sensitive tissues.Protection from strong visible radiation is also aff orded by increased surface light refl ectance.Moreover,the mixtures of trichome phenolics represent a superfi-cial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens.Although the cells of some trichomes die at maturity,they can modulate their quantitative and qualitative characteristics during development,depending on the prevailing conditions of the external biotic or abiotic environment.In fact,the structure and chemical constituents of trichomes may change due to the particular light regime,herbivore damage,wounding,water stress,salinity and the presence of heavy metals.Hence,trichomes represent dynamic protective structures that may greatly aff ect the outcome of many plant–environment interactions.展开更多
Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 ...Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.展开更多
Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in th...Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS,GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression.展开更多
Nowadays, the network defence policy selection using game model of incomplete information ignores the type of the defender, which quantifies cost simply, resulting in unreasonable defence policies selection. Aiming at...Nowadays, the network defence policy selection using game model of incomplete information ignores the type of the defender, which quantifies cost simply, resulting in unreasonable defence policies selection. Aiming at the problem, we use Bayesian game theory to model the active defence policy selection. We take the types of both the attacker and the defender into consideration. Besides, the traditional quantization method is enhanced. Then, we calculate the equilibrium of static Bayesian game. Based on the analysis of the equilibrium, we select the optimal defence policy through the prediction for attackers' actions. The paper calculates the defence effectiveness of defence policies and provides a defence policies selection algorithm. Ultimately, we present an example to verify the effectiveness of the method and model proposed in the paper.展开更多
This article presents the texture development of magnesium AZ31 alloy in the accumulative roll bonded(ARB) AZ31/AZ31 multilayer and AZ31/AA5086 laminate composite.The comparative study demonstrates that the texture ev...This article presents the texture development of magnesium AZ31 alloy in the accumulative roll bonded(ARB) AZ31/AZ31 multilayer and AZ31/AA5086 laminate composite.The comparative study demonstrates that the texture evolution in AZ31 in a multilayer system is strongly influenced by the interfaces.A typical basal texture of AZ31 has been observed in AZ31/AZ31 multilayer with texture intensity increased with the rolling deformation.Presence of AZ31/AA5086 interface in the laminate composite leads to a tilted basal texture along the rolling direction(RD) in AZ31 alloy.The texture intensity of composite increased initially with rolling reduction and weakened at the higher rolling strain.Weakening of texture in AZ31 during the laminate processing at higher strain has been attributed to the development of wavy interfaces in AZ31/AA5086 laminate.展开更多
Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties w...Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions.Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint.This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions.This study covers an in-depth analysis of effect extreme temperature,mechanical stress,and radiation conditions towards solder joint.Impact of each condition to the microstructure including solder matrix and intermetallic compound layer,and mechanical properties such as fatigue,shear strength,creep,and hardness was thoroughly discussed.The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding.Furthermore,the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions.The findings offer valuable guidance for researchers,engineers,and practitioners involved in electronics,engineering,and related fields,fostering advancements in solder joint reliability and performance.展开更多
Nowadays, security defence of network uses the game theory, which mostly applies complete information game model or even the static game model. To get closer to the actual network and defend actively, we propose a net...Nowadays, security defence of network uses the game theory, which mostly applies complete information game model or even the static game model. To get closer to the actual network and defend actively, we propose a network attack-defence game model by using signalling game, which is modelled in the way of dynamic and incomplete information. We improve the traditional attack-defence strategies quantization method to meet the needs of the network signalling game model. Moreover, we give the calculation of the game equilibrium and analyse the optimal defence scheme. Finally, we analyse and verify effectiveness of the model and method through a simulation experiment.展开更多
Background:Gram-negative bacterial infections have a major economic impact on both the livestock industry and public health.Toll-like receptor 4(TLR4)plays a crucial role in host defence against Gram-negative bacteria...Background:Gram-negative bacterial infections have a major economic impact on both the livestock industry and public health.Toll-like receptor 4(TLR4)plays a crucial role in host defence against Gram-negative bacteria.Exploring the defence mechanism regulated by TLR4 may provide new targets for treatment of inflammation and control of bacterial infections.In a previous study,we generated transgenic sheep overexpressing TLR4 by microinjection to improve disease resistance.The defence mechanism through which TLR4 overexpression protected these sheep against pathogens is still not fully understood.Results:In the present study,we used Escherichia coli to infect monocytes isolated from peripheral blood of the animal model.The overexpression of TLR4 strongly enhanced the percentage of endocytosis and capacity of elimination in monocytes during the early stages of infection.This phenomenon was mainly due to overexpression of TLR4 promoting caveolae-mediated endocytosis.Pretreatment of the transgenic sheep monocytes with inhibitors of TLR4,Src signalling,or the caveolae-mediated endocytosis pathway reduced the internalization of bacteria,weakened the ability of the monocytes to eliminate the bacteria,and increased the pH of the endosomes.Conclusion:Together,our results reveal the effects of TLR4 on the control of E.coli infection in the innate immunity of sheep and provide crucial evidence of the caveolae-mediated endocytosis pathway required for host resistance to invading bacteria in a large animal model,providing theoretical support for breeding disease resistance in the future.Furthermore,Src and caveolin 1(CAV1)could be potentially valuable targets for the control of infectious diseases.展开更多
AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow ...AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.RESULTS The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 m L/min·g in males and 0.51 ± 0.03 m L/min·g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 μm and 80 ± 3 μm respectively. After 60 min the mucus thickness increased to 113 ± 3 μm in males and 121 ± 3 μm in females with no statistically significant difference seen between the sexes. Following oestrogen administration(0.1 followed by 1 μg/kg·min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline(P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 m L/min·100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 m L/min·100 g in females(P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM)(0.06 ± 0.07) and females(0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP(P = 0.14).CONCLUSION Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration.展开更多
The article presents problems related to mechanical protection of vehicles with different add-on armours against chemical,biological and radiological contamination.This applies to vehicles with additional passive,reac...The article presents problems related to mechanical protection of vehicles with different add-on armours against chemical,biological and radiological contamination.This applies to vehicles with additional passive,reactive and hybrid protection in the form of cassettes against piercing with anti-tank projectiles,piercing with their kinetic energy of impact,and as a result of chemical energy of shaped charges as well as explosively formed projectiles.It has been shown how increased ballistic protection of these vehicles at the same time reduces their decontaminability in various places of the vehicle due to the increased additional surface of the vehicle with cassettes.Prevention of contamination of these cassettes has been presented as a way of reducing hard to reach surface for decontamination and a method of insulating construction elements(stands),fixing these cassettes to the vehicle,from the environment to prevent contact with contaminated liquids and dusts.The selection of appropriate materials is shown,which may affect the improvement of the decontamination efficiency of the vehicle with such cassettes.This applies to the use of materials with low absorption of chemical warfare agents,which prevent the accumulation of large amounts of these agents on contaminated surfaces and improve the effectiveness of decontamination.It also shows how to ensure better access of the disinfectant to as much of the vehicle surface as possible,covered with cassettes that have been contaminated.It shows how a vehicle,in particular with such cassettes,can provide protection against radar detection when Radar Absorbent Material is used on vehicle cassettes.展开更多
The Saemangeum project includes well-developed tidal flats, two estuaries of the Mankyeong and Dongjin rivers, and a chain of small iskands in the outer area off the dike by reclaiming a surface area of 40100 ha. A lo...The Saemangeum project includes well-developed tidal flats, two estuaries of the Mankyeong and Dongjin rivers, and a chain of small iskands in the outer area off the dike by reclaiming a surface area of 40100 ha. A long sea dike of 30 km has been constructed in the mid-west area of Korea. This paper describes the construction of tidal dikes focusing on the final closure operation performed in April, 2006 employing intermediate technology. Predictive modelling was also carried out to predict the real-time flow fields during the gradual closure operation of the final stage.展开更多
Plants in their natural environment are constantly subjected to various abiotic and biotic stressors and,therefore,have developed several defense mechanisms to maintain fitness.Stress responses are intricate and requi...Plants in their natural environment are constantly subjected to various abiotic and biotic stressors and,therefore,have developed several defense mechanisms to maintain fitness.Stress responses are intricate and require various physiological,biochemical,and cellular changes in plants.The reaction mechanisms in plants subjected to drought,salinity,or heat stress alone have been explained in numerous studies.However,the field conditions are significantly different from the controlled laboratory conditions.In the field,crops or plants are simultaneously exposed to two or more abiotic and/or biotic stress conditions,such as a combination of salinity and heat,drought and cold,or any of the abiotic stresses combined with pathogen infection.Studies have shown that plants’reactions to combinations of more than two stress factors are distinct and cannot be explicitly deduced from their responses to different stresses when applied separately.Therefore,additional research is needed to understand the complete mechanism of plant responses to stress by analyzing data between single stress and multiple stress responses.This review aims to provide an overview of current research on plant responses to a combination of various stress conditions and their influence on the metabolic,transcriptional,and physiological characteristics of plants.展开更多
基金supported by the National Natural Science Foundation of China(31660170,31870524,32071663)Outstanding Young Teacher Program(2020GGJS006).
文摘Native herbivory may be detrimental to plant fitness and thus can contribute a biotic resistance to exotic plant invasion.Eupatorium adenophorum,a non-native species,has formed dense monocultures in many southern Provinces of China.Because several native generalist insects feed on E.adenophorum,we evaluated whether the lower level of induced defences and greater compensatory growth contributed to successful invasion of E.adenophorum by comparison with a native congener E.heterophyllum.Early events in the jasmonic acid cascade and chlorophyll fluorescence,non-target metabolomic profiles and recovery in biomass compensation of E.adenophorum and its native congener E.heterophyllum were measured during mechanical wounding and herbivory by the generalist insect Helicoverpa armigera.Mechanical and simulated chewing damage immediately initiated defences in the two species.However,E.heterophyllum was more sensitive to tissue loss,and it produced more metabolic defensive compounds than invasive E.adenophorum.Although H.armigera feeding amplified the effects of mechanical wounding on defence induction,the biomass of E.adenophorum was only weakly affected,as its higher compensatory growth could offset the biomass loss and metabolic cost.Overall,our results suggest that H.armigera herbivory and mechanical wounding could induce different physiological responses,and are often specific to invasive E.adenophorum and native E.heterophyllum.Moreover,lower metabolic defences and higher compensation growth may contribute to the invasion success of E.adenophorum.
基金the call of“Ciencia de Frontera”(CF 2023-1-2756Consejo Nacional de Humanidades,Ciencias y Tecnologias).
文摘The seedling phase represents an initial and critical stage for the establishment of individuals in the ecosystem.During this stage,specialized metabolites contribute to survival;however,studies analyzing the presence of these molecules and the reasons for their production and accumulation are still scarce.Annonaceae is a botanical family recognized for the chemodiversity of its secondary metabolites;nearly 1000 alkaloids have been reported in approximately 150 adult specimens.The aim of this studywas to determinewhether alkaloid biosynthesis in Annonaceae is expressed from early stages.For this purpose,Annona macroprophyllata,Annona muricata,Annona purpurea,and Annona reticulata seedlings,tropical Annonaceae with a history of alkaloids in adult stages,were studied.Alkaloidswere extracted using the selective acid-basemethod fromroots,stems,and leaves of seedlings with one to two pairs of leaves.The chemical composition analysis was performed using gas chromatography coupled to a mass spectrum.The identity of molecules was confirmed with standards and bibliographical references.Alkaloids were detected in the tissues of all species,and 28 of these metabolites were identified,92%with a benzylisoquinoline structure.Many of them have reports of various biological activities.These alkaloids are not derived fromthe mother plant,as no alkaloidswere found in the seeds.Nine,nine,eight,and twenty alkaloids were detected in seedlings of A.macroprophyllata,A.muricata,A.reticulata,and A.purpurea,respectively.The roots of all species are the organs with the most alkaloids(both in abundance and chemical richness).In conclusion,alkaloid metabolism is expressed during the early development stages in Annonaceae and could be associated with the chemical defense theory.These findings enhance our understanding of how seedlings use chemical strategies to adapt to their environment.They also demonstrate that seedlings can produce active compounds,even when grown under controlled conditions.
文摘The study aimed to develop a customized Data Governance Maturity Model (DGMM) for the Ministry of Defence (MoD) in Kenya to address data governance challenges in military settings. Current frameworks lack specific requirements for the defence industry. The model uses Key Performance Indicators (KPIs) to enhance data governance procedures. Design Science Research guided the study, using qualitative and quantitative methods to gather data from MoD personnel. Major deficiencies were found in data integration, quality control, and adherence to data security regulations. The DGMM helps the MOD improve personnel, procedures, technology, and organizational elements related to data management. The model was tested against ISO/IEC 38500 and recommended for use in other government sectors with similar data governance issues. The DGMM has the potential to enhance data management efficiency, security, and compliance in the MOD and guide further research in military data governance.
文摘The liver is considered a vital organ and is the hub for multiple chemical functions,such as intermediary metabolism and the detoxification of ingested toxins,which are essential for the preservation of life,hence,the origin or the word“liver”.The liver has enormous,highly diversified catalytic potential.This enormous catalytic potential generates massive oxidative stress,which is important for the functions of the liver but is detrimental to the viability of the liver.The liver receives approximately 80%of its blood supply from the portal vein,which brings less saturated blood from the gastrointestinal tract.Hepatocytes operate in a relatively hypoxic microenvironment due to this portal inflow.The development of this hypoxic microenvironment of the liver is an important evolutionary adaptation for its detoxification function that is not recognized in the literature as a defence mechanism against the oxidative stress generated during the detoxification process.This review describes liver function in relation to its oxidative catalytic potential and the oxidative stress generated by it as well as the evolutionary defence mechanisms present in the liver against this oxidative stress to provide new insights into liver function.
文摘The defence sector is now at an advanced level,catering to the global scenario,and countries also invest heavily in research and development.Countries around the world have spent a lot of money on research and development over the years in order to stay ahead of their competitors.Lightweight materials are critical in defence applications because they allow components to be lighter without sacrificing strength.This review provides an overview of the research related to defence applications.The book provides comprehensive details on current trends in the application of lightweight materials in defence.This review also includes historical and current perspectives on defence technologies.It discusses uses of lightweight materials such as metal matrix composites,polymer composites,ceramic matrix composites,fiber composites in defence sectors Finally,the review paper also emphasizes future military applications of lightweight materials.
文摘Carbon-based composites, including carbon reinforced composites and carbon-matrix composites, in defence technologies have raised a lot of attention due to its significant physical capabilities, superior thermal and mechanical stability, and its eco-friendly nature. Carbon-based composite which incorporating with various carbonaceous materials such as coke, char, black carbon, activated carbon, carbon fibre and other carbon nanomaterials (carbon nanotubes, carbon nanofibres, graphene and graphite) are the greatest viable option for the development of advanced defence technologies. In this review article the characteristics of carbon-based materials and its composites are discussed for their distinct application in defence sectors;aeronautics, maritime, automotive, electronics, energy storage, electromagnetic interference (EMI) shielding and structures. The origin of carbonaceous materials and its production techniques were discussed. Carbon-based composites have a promising future in defence technology, particularly in chemical sensors, drug delivery agents, radar technologies, and nanocomposites due to their low cost, easy availability, flexibility in design and processing.
基金The Deutsche Forschungsgemeinschaft, No. Ni575/4-1
文摘The gastrointestinal innate and adaptive immune system continuously faces the challenge of potent stimuli from the commensal microflora and food constituents. These local immune responses require a tight control, the outcome of which is in most cases the induction of tolerance. Local T cell immunity is an important compartment of the specif ic intestinal immune system. T cell reactivity is programmed during the initial stage of its activation by professional presenting cells. Mucosal dendritic cells (DCs) are assumed to play key roles in regulating immune responses in the antigen-rich gastrointestinal environment. Mucosal DCs are a heterogeneous population that can either initiate (innate and adaptive) immune responses, or control intestinal inflammation and maintain tolerance. Defects in this regulation are supposed to lead to the two major forms of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC). This review will discuss the emerging role of mucosal DCs in regulating intestinal inflammation and immune responses.
文摘Aim: To find out whether the response of testicular oxidative stress parameters to hexachlorocyclohexane (HCH) is species specific. Methods: In rats and mice (n=5 in each group), HCH was administered at a dose of 20 mg/kg/day intraperitoneally for 30 days in 0.1 ml of refined groundnut oil. The control groups received equal volume of the vehicle. Animals were sacrificed 24 hours after the last injection and various oxidative stress parameters were measured immediately. Results: The level of both endogenous as well as FeSO_4 and ascorbic acid-stimulated lipid peroxidation was increased significantly in the HCH-treated rats, whereas the pattern was just the reverse in case of mice. Although the level of H_2O_2 content increased in response to HCH in both groups, a totally different trend was observed for the activity of the principal H_2O_2-metabolising enzyme, catalase. In case of rats, a significant decline in the activity of catalase was recorded in response to HCH whereas a sharp augmentation in the enzyme activity was noticed in mice. Similarly, the decreased activity of superoxide dismutase observed in rats remained unaltered in mice. Conclusion: HCH induces oxidative stress in the testis of both rats and mice. However, the pattern of response of testicular oxidative stress parameters seems to be species specific.
基金partially funded by the Greek General Secretariat of Research and Technologythe Greek Scholarship FoundationThe ’Empirikion’ Foundation
文摘As superficial structures,non-glandular trichomes,protect plant organs against multiple biotic and abiotic stresses.The protective and defensive roles of these epidermal appendages are crucial to developing organs and can be attributed to the excellent combination of suitable structural traits and chemical reinforcement in the form of phenolic compounds,primarily fl avonoids.Both the formation of trichomes and the accumulation of phenolics are interrelated at the molecular level.During the early stages of development,non-glandular trichomes show strong morphological similarities to glandular ones such as the balloon-like apical cells with numerous phenolics.At later developmental stages,and during secondary wall thickening,phenolics are transferred to the cell walls of the trichomes.Due to the diff use deposition of phenolics in the cell walls,trichomes provide protection against UV-B radiation by behaving as optical fi lters,screening out wavelengths that could damage sensitive tissues.Protection from strong visible radiation is also aff orded by increased surface light refl ectance.Moreover,the mixtures of trichome phenolics represent a superfi-cial chemical barrier that provides protection against biotic stress factors such as herbivores and pathogens.Although the cells of some trichomes die at maturity,they can modulate their quantitative and qualitative characteristics during development,depending on the prevailing conditions of the external biotic or abiotic environment.In fact,the structure and chemical constituents of trichomes may change due to the particular light regime,herbivore damage,wounding,water stress,salinity and the presence of heavy metals.Hence,trichomes represent dynamic protective structures that may greatly aff ect the outcome of many plant–environment interactions.
文摘Messenger RNA （mRNA） turnover in eukaryotic cells begins with shortening of the poly （A） tail at the 3＇ end, a process called deadenylation. In yeast, the deadenylation reaction is predominantly mediated by CCR4 and CCR4- associated factor 1 （CAF1）, two components of the well-characterised protein complex named CCR4-NOT. We report here that AtCAF1a and AtCAF1b, putative Arabidopsis homologs of the yeast CAF1 gene, partially complement the growth defect of the yeast call mutant in the presence of caffeine or at high temperatures. The expression of At-CAF1a and AtCAFlb is induced by multiple stress-related hormones and stimuli. Both AtCAF1a and AtCAFlb show deadenylation activity in vitro and point mutations in the predicted active sites disrupt this activity. T-DNA insertion mutants disrupting the expression of AtCAF1a and/or AtCAF1b are defective in deadenylation of stress-related mRNAs, indicating that the two AtCAF1 proteins are involved in regulated mRNA deadenylation in vivo. Interestingly, the single and double mutants of AtCAF1a and AtCAFlb show reduced expression of pathogenesis-related （PR） genes PR1 and PR2 and are more susceptible to Pseudomonas syringae pv tomato DC3000 （Pst DC3000） infection, whereas transgenic plants over-expressing AtCAFla show elevated expression of PR1 and PR2 and increased resis-tance to the same pathogen. Our results suggest roles of the AtCAF1 proteins in regulated mRNA deadenylation and defence responses to pathogen infections.
基金This work was supported by the National Natural Science Foundation of China(No.39870050)the Chinese Academy of Sciences(Grant No.KSCX2-SW-322).
文摘Responses to oligogalacturonic acid (OGA) were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium ([Ca2+]cyt) that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS,GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or NADPH oxidase, indicating that increases in both cytosolic calcium and H2O2 are required for OGA-induced gene expression.
基金supported by the National Natural Science Foundation of China under Grant No. 61303074 and No. 61309013the Henan Province Science and Technology Project Funds under Grant No. 12210231002
文摘Nowadays, the network defence policy selection using game model of incomplete information ignores the type of the defender, which quantifies cost simply, resulting in unreasonable defence policies selection. Aiming at the problem, we use Bayesian game theory to model the active defence policy selection. We take the types of both the attacker and the defender into consideration. Besides, the traditional quantization method is enhanced. Then, we calculate the equilibrium of static Bayesian game. Based on the analysis of the equilibrium, we select the optimal defence policy through the prediction for attackers' actions. The paper calculates the defence effectiveness of defence policies and provides a defence policies selection algorithm. Ultimately, we present an example to verify the effectiveness of the method and model proposed in the paper.
基金The authors are thankful to Dr.Mano Misra and Dr.Pradeep Menezes both at University of Nevada,Reno for valuable discussion.
文摘This article presents the texture development of magnesium AZ31 alloy in the accumulative roll bonded(ARB) AZ31/AZ31 multilayer and AZ31/AA5086 laminate composite.The comparative study demonstrates that the texture evolution in AZ31 in a multilayer system is strongly influenced by the interfaces.A typical basal texture of AZ31 has been observed in AZ31/AZ31 multilayer with texture intensity increased with the rolling deformation.Presence of AZ31/AA5086 interface in the laminate composite leads to a tilted basal texture along the rolling direction(RD) in AZ31 alloy.The texture intensity of composite increased initially with rolling reduction and weakened at the higher rolling strain.Weakening of texture in AZ31 during the laminate processing at higher strain has been attributed to the development of wavy interfaces in AZ31/AA5086 laminate.
基金fully supported by a Tabung Amanah Pusat Pengurusan Penyelidikan&Inovasi(PPPI)(Grant No.PS060-UPNM/2023/GPPP/SG/1)Universiti Pertahanan Nasional Malaysia(UPNM)for funding this study。
文摘Solder joint,crucial component in electronic systems,face significant challenges when exposed to extreme conditions during applications.The solder joint reliability involving microstructure and mechanical properties will be affected by extreme conditions.Understanding the behaviour of solder joints under extreme conditions is vital to determine the durability and reliability of solder joint.This review paper aims to comprehensively explore the underlying failure mechanism affecting solder joint reliability under extreme conditions.This study covers an in-depth analysis of effect extreme temperature,mechanical stress,and radiation conditions towards solder joint.Impact of each condition to the microstructure including solder matrix and intermetallic compound layer,and mechanical properties such as fatigue,shear strength,creep,and hardness was thoroughly discussed.The failure mechanisms were illustrated in graphical diagrams to ensure clarity and understanding.Furthermore,the paper highlighted mitigation strategies that enhancing solder joint reliability under challenging operating conditions.The findings offer valuable guidance for researchers,engineers,and practitioners involved in electronics,engineering,and related fields,fostering advancements in solder joint reliability and performance.
基金supported by the National Natural Science Foundation of China under Grant No. 61303074 and No. 61309013the Henan Province Science and Technology Project Funds under Grant No. 12210231002
文摘Nowadays, security defence of network uses the game theory, which mostly applies complete information game model or even the static game model. To get closer to the actual network and defend actively, we propose a network attack-defence game model by using signalling game, which is modelled in the way of dynamic and incomplete information. We improve the traditional attack-defence strategies quantization method to meet the needs of the network signalling game model. Moreover, we give the calculation of the game equilibrium and analyse the optimal defence scheme. Finally, we analyse and verify effectiveness of the model and method through a simulation experiment.
基金supported by National Science and Technology Major Project of China(2016ZX08008-003).
文摘Background:Gram-negative bacterial infections have a major economic impact on both the livestock industry and public health.Toll-like receptor 4(TLR4)plays a crucial role in host defence against Gram-negative bacteria.Exploring the defence mechanism regulated by TLR4 may provide new targets for treatment of inflammation and control of bacterial infections.In a previous study,we generated transgenic sheep overexpressing TLR4 by microinjection to improve disease resistance.The defence mechanism through which TLR4 overexpression protected these sheep against pathogens is still not fully understood.Results:In the present study,we used Escherichia coli to infect monocytes isolated from peripheral blood of the animal model.The overexpression of TLR4 strongly enhanced the percentage of endocytosis and capacity of elimination in monocytes during the early stages of infection.This phenomenon was mainly due to overexpression of TLR4 promoting caveolae-mediated endocytosis.Pretreatment of the transgenic sheep monocytes with inhibitors of TLR4,Src signalling,or the caveolae-mediated endocytosis pathway reduced the internalization of bacteria,weakened the ability of the monocytes to eliminate the bacteria,and increased the pH of the endosomes.Conclusion:Together,our results reveal the effects of TLR4 on the control of E.coli infection in the innate immunity of sheep and provide crucial evidence of the caveolae-mediated endocytosis pathway required for host resistance to invading bacteria in a large animal model,providing theoretical support for breeding disease resistance in the future.Furthermore,Src and caveolin 1(CAV1)could be potentially valuable targets for the control of infectious diseases.
文摘AIM To evaluate sex differences and the effects of oestrogen administration in rat gastric mucosal defence.METHODS Sex differences in gastric mucus thickness and accumulation rate, absolute gastric mucosal blood flow using microspheres, the integrity of the gastric mucosal epithelium in response to a chemical irritant and the effects of oestrogen administration on relative gastric mucosal blood flow in an acute setting was assessed in an in vivo rat experimental model. Subsequently, sex differences in the distribution of oestrogen receptors and calcitonin gene related peptide in the gastric mucosa of animals exposed to oestrogen in the above experiments was evaluated using immunohistochemistry.RESULTS The absolute blood flow in the GI-tract was generally higher in males, but only significantly different in the corpus part of the stomach (1.12 ± 0.12 m L/min·g in males and 0.51 ± 0.03 m L/min·g in females) (P = 0.002). After removal of the loosely adherent mucus layer the thickness of the firmly adherent mucus layer in males and females was 79 ± 1 μm and 80 ± 3 μm respectively. After 60 min the mucus thickness increased to 113 ± 3 μm in males and 121 ± 3 μm in females with no statistically significant difference seen between the sexes. Following oestrogen administration(0.1 followed by 1 μg/kg·min), mean blood flow in the gastric mucosa decreased by 31% [68 ± 13 perfusion units (PFU)] in males which was significantly different compared to baseline(P = 0.02). In females however, mean blood flow remained largely unchanged with a 4% (5 ± 33 PFU) reduction. The permeability of the gastric mucosa increased to a higher level in females than in males (P = 0.01) after taurocholate challenge. However, the calculated mean clearance increase did not significantly differ between the sexes [0.1 ± 0.04 to 1.1 ± 0.1 m L/min·100 g in males and 0.4 ± 0.3 to 2.1 ± 0.3 m L/min·100 g in females(P = 0.065)]. There were no significant differences between 17β-Estradiol treated males (mean ratio of positive staining ± SEM)(0.06 ± 0.07) and females(0.11 ± 0.11) in the staining of ERα (P = 0.24). Also, there were no significant differences between 17β-Estradiol treated males (0.18 ± 0.21) and females (0.06 ± 0.12) in the staining of ERβ (P = 0.11). Finally, there were no significant differences between 17β-Estradiol treated males (0.04 ± 0.05) and females (0.11 ± 0.10) in the staining of CGRP(P = 0.14).CONCLUSION Gastric mucosal blood flow is higher in male than in female rats and is reduced in male rats by oestrogen administration.
文摘The article presents problems related to mechanical protection of vehicles with different add-on armours against chemical,biological and radiological contamination.This applies to vehicles with additional passive,reactive and hybrid protection in the form of cassettes against piercing with anti-tank projectiles,piercing with their kinetic energy of impact,and as a result of chemical energy of shaped charges as well as explosively formed projectiles.It has been shown how increased ballistic protection of these vehicles at the same time reduces their decontaminability in various places of the vehicle due to the increased additional surface of the vehicle with cassettes.Prevention of contamination of these cassettes has been presented as a way of reducing hard to reach surface for decontamination and a method of insulating construction elements(stands),fixing these cassettes to the vehicle,from the environment to prevent contact with contaminated liquids and dusts.The selection of appropriate materials is shown,which may affect the improvement of the decontamination efficiency of the vehicle with such cassettes.This applies to the use of materials with low absorption of chemical warfare agents,which prevent the accumulation of large amounts of these agents on contaminated surfaces and improve the effectiveness of decontamination.It also shows how to ensure better access of the disinfectant to as much of the vehicle surface as possible,covered with cassettes that have been contaminated.It shows how a vehicle,in particular with such cassettes,can provide protection against radar detection when Radar Absorbent Material is used on vehicle cassettes.
基金supported bythe Korea Research Council of Fundamental Science &Technology (GrantNo.PG47491)the Korea Oceam Research &Development Institute (Grant No.PE98501)
文摘The Saemangeum project includes well-developed tidal flats, two estuaries of the Mankyeong and Dongjin rivers, and a chain of small iskands in the outer area off the dike by reclaiming a surface area of 40100 ha. A long sea dike of 30 km has been constructed in the mid-west area of Korea. This paper describes the construction of tidal dikes focusing on the final closure operation performed in April, 2006 employing intermediate technology. Predictive modelling was also carried out to predict the real-time flow fields during the gradual closure operation of the final stage.
基金the University Grants Commission(UGC-BSR Research Start-up-Grant No.F30-409/2018)the Deanship of Scientific Research,King Khalid University,Saudi Arabia(No.R.G.P.2/11/42)for their financial assistance。
文摘Plants in their natural environment are constantly subjected to various abiotic and biotic stressors and,therefore,have developed several defense mechanisms to maintain fitness.Stress responses are intricate and require various physiological,biochemical,and cellular changes in plants.The reaction mechanisms in plants subjected to drought,salinity,or heat stress alone have been explained in numerous studies.However,the field conditions are significantly different from the controlled laboratory conditions.In the field,crops or plants are simultaneously exposed to two or more abiotic and/or biotic stress conditions,such as a combination of salinity and heat,drought and cold,or any of the abiotic stresses combined with pathogen infection.Studies have shown that plants’reactions to combinations of more than two stress factors are distinct and cannot be explicitly deduced from their responses to different stresses when applied separately.Therefore,additional research is needed to understand the complete mechanism of plant responses to stress by analyzing data between single stress and multiple stress responses.This review aims to provide an overview of current research on plant responses to a combination of various stress conditions and their influence on the metabolic,transcriptional,and physiological characteristics of plants.
