Background Leprosy remains a persistent public health challenge,where human-to-human transmission of Mycobacterium leprae via respiratory droplets is well established.In the tropical Americas,growing evidence implicat...Background Leprosy remains a persistent public health challenge,where human-to-human transmission of Mycobacterium leprae via respiratory droplets is well established.In the tropical Americas,growing evidence implicates armadillos as important zoonotic reservoirs,particularly through direct contact during hunting and handling.However,such transmission has so far been considered rare and highly localised.This study provides a comprehensive spatial analysis of the role of armadillo hunting in human leprosy transmission,quantifying its contribution to disease prevalence and identifying geographic hotspots where interventions could be most effective.Methods Using Brazil’s 326,001 reported leprosy cases from 2013 to 2022,we applied a pathogeographical approach to explore transmission dynamics.We compiled data on 554 hunted armadillos across 175 municipalities and M.leprae prevalence in 376 armadillo individuals from 97 municipalities(mean prevalence=38.5%).These were used to build spatial models assessing hunting-related infection risk and integrated as a variable into a generalised linear model alongside socioeconomic,climatic,and environmental predictors to evaluate their effects on human leprosy prevalence.Results Key predictors of armadillo hunting included higher population density(P<0.001)and firearm availability(P<0.01).Infection in armadillos was negatively correlated with native habitat coverage(coefficient:−2.28;P<0.001),suggesting that environmental degradation can amplify infection risk.The armadillo-hunting infection risk variable—generated by combining armadillo hunting and infection favourability models—emerged as the second strongest predictor of human leprosy prevalence(coefficient:1.69;P<0.001),accounting for~25%of cases nationally and around 40%in deforestation hotspots.Additional positive predictors included greater precipitation seasonality(coefficient:0.82;P<0.001)and malnutrition(coefficient:0.01;P<0.001),while higher population density(coefficient:−0.64;P<0.001),natural habitat coverage(coefficient:−0.50;P<0.001)and socioeconomic status(coefficient:−0.47;P=0.013)were linked to reduced disease prevalence.Conclusions Armadillo hunting seems to play a more significant role in human leprosy transmission than previously recognised.To address this overlooked pathway,targeted interventions should focus on reducing unsafe and illegal hunting,improving communication around zoonotic risks,strengthening disease surveillance in high-risk areas,and conducting genetic studies to confirm wildlife-to-human transmission.Our findings highlight the importance of incorporating wildlife-associated transmission pathways into strategies to reduce disease prevalence and mitigate future outbreaks in tropical regions facing rapid environmental change and persistent poverty.展开更多
Chronic obstructive pulmonary disease(COPD)is one of the leading causes of death and disability worldwide.Its complex etiology involves factors such as smoking,air pollution,genetic susceptibility,and social environme...Chronic obstructive pulmonary disease(COPD)is one of the leading causes of death and disability worldwide.Its complex etiology involves factors such as smoking,air pollution,genetic susceptibility,and social environment.With the accelerating global aging population and urbanization,the incidence and burden of COPD continue to rise.Current treatment strategies for COPD are relatively conservative,primarily focusing on bronchodilators,inhaled corticosteroids,and long-term oxygen therapy.Although these approaches can alleviate symptoms and slow disease progression to some ex-tent,they fail to effectively target the underlying mechanisms of the disease,leaving an unmet clinical need for more-effective therapies.This highlights the urgency of de-veloping innovative drugs that are both safe and efficacious to address the challenges in COPD treatment.As a traditional Chinese medicine with a long history,Colla corii asini has garnered significant attention for its diverse pharmacological effects and fa-vorable safety profile.Research has shown that Colla corii asini possesses multiple bio-logical activities,including hematopoiesis,nourishing the lungs,enhancing immunity,anti-infection,antiaging,antitumor,and antifatigue effects.Moreover,it has demon-strated potential in regulating oxidative stress,immune imbalance,and inflammatory responses.Recent evidence suggests that Colla corii asini may play a protective role in lung function through multitarget and multipathway mechanisms.Based on previ-ous research findings,this paper explores the potential therapeutic value of Colla corii asini in COPD treatment by addressing the current clinical management challenges and identifying potential therapeutic targets.It also integrates the pharmacological effects of Colla corii asini into a broader treatment context,providing new perspec-tives for comprehensive COPD management and laying the theoretical foundation for its modernization and innovative application.展开更多
Rubberized concrete is one of the most studied applications of discarded tires and offers a promising approach to developing materials with enhanced properties.The rubberized concrete mixture results in a reduced modu...Rubberized concrete is one of the most studied applications of discarded tires and offers a promising approach to developing materials with enhanced properties.The rubberized concrete mixture results in a reduced modulus of elasticity and a reduced compressive and tensile strength compared to traditional concrete.This study employs finite element simulations to investigate the elastic properties of rubberized mortar(RuM),considering the influence of inclusion stiffness and interfacial debonding.Different homogenization schemes,including Voigt,Reuss,and mean-field approaches,are implemented using DIGIMAT and ANSYS.Furthermore,the influence of the interfacial transition zone(ITZ)between mortar and rubber is analyzed by periodic homogenization.Subsequently,the influence of the ITZ is examined through a linear fracture analysis with the stress intensity factor as a key parameter,using the ANSYS SMART crack growth tool.Finally,a non-linear study in FEniCS is carried out to predict the strength of the composite material through a compression test.Comparisons with high density polyethylene(HDPE)and gravel inclusions show that increasing inclusion stiffness enhances compressive strength far more effectively than simply improving the mortar/rubber bond.Indeed,when the inclusions are much softer than the surrounding matrix,any benefit gained on the elastic modulus or strength from stronger interfacial adhesion becomes almost negligible.This study provide numerical evidence that tailoring the rubber’s intrinsic stiffness—not merely strengthening the rubber/mortar interface—is a decisive factor for improving the mechanical performance of RuM.展开更多
In order to improve the knowledge of the precipitation mechanism in martensitic steels containing carbon,XRD synchrotron experiments were performed. Firstly, the influence of Ni,Co and Al were studied and it was found...In order to improve the knowledge of the precipitation mechanism in martensitic steels containing carbon,XRD synchrotron experiments were performed. Firstly, the influence of Ni,Co and Al were studied and it was found that the precipitation of iron carbides occurs in same way as in Fe-C steel. However, with the addition of molybdenum and chromium in same steels, XRD synchrotron investigations clearly showed alloyed carbides directly precipitate, thereby preventing the iron carbides formation.展开更多
The continuous growth in the manufacture of aerospace components such as blisks has led to an increase in the application of different hybrid materials fabricating methods,and thus the requirements for joining and str...The continuous growth in the manufacture of aerospace components such as blisks has led to an increase in the application of different hybrid materials fabricating methods,and thus the requirements for joining and strengthening of dissimilar welds.According to this goal,selective laser melted(SLM)Inconel718 was joined with forged AD730^(TM)Nickel-based superalloy through linear friction welding(LFW)in this study.Microstructure variation,specifically with respect to secondary phases precipitation was investigated.The microhardness and strengthening mechanisms of the weldment were also studied.The precipitation(volume fraction and size of particles)at different regions of both sides of the weld line was characterized.Close to the weld line,the dissolution ofγ’/γ"and Laves phases and grain refinement occurred which reveals the effects of both compression strain and high temperature on recrystallization and high degree of elemental diffusion in the weld zone(WZ).It is shown that the size,volume fraction,and shape of secondary phases increased and changed(from spherical to long-striped for Laves particles)as we went from the WZ toward the base metal.However,the measured microhardness indicated that the strength of AD730^(TM)alloy depends significantly on the grain size,while strength in SLM Inconel 718 was dominated by shape(or size)and the presence of secondary phases(γ’/γ"and Laves).展开更多
This study analyze the relation between body composition, physical activity （PA）, and sex in Chilean children from rural and urban public educational institutions. The prevalence of obesity （according to BMI） was ...This study analyze the relation between body composition, physical activity （PA）, and sex in Chilean children from rural and urban public educational institutions. The prevalence of obesity （according to BMI） was 30.88% in urban children and 28.93% in rural children. Central obesity presented mainly in the rural girls. Approximately 90% of the participants reported 〈7 h of PA/week, regardless of residential area. In addition, central fat was strongly associated with rural residence; the children reported lower PA levels, and they presented a higher prevalence of central fat. The results reflect the need to implement programs to improve PA conditions in the child urban-rural population.展开更多
Airframe maintenance is traditionally performed at scheduled maintenance stops.The decision to repair a fuselage panel is based on a fixed crack size threshold,which allows to ensure the aircraft safety until the next...Airframe maintenance is traditionally performed at scheduled maintenance stops.The decision to repair a fuselage panel is based on a fixed crack size threshold,which allows to ensure the aircraft safety until the next scheduled maintenance stop.With progress in sensor technology and data processing techniques,structural health monitoring（SHM） systems are increasingly being considered in the aviation industry.SHM systems track the aircraft health state continuously,leading to the possibility of planning maintenance based on an actual state of aircraft rather than on a fixed schedule.This paper builds upon a model-based prognostics framework that the authors developed in their previous work,which couples the Extended Kalman filter（EKF） with a firstorder perturbation（FOP） method.By using the information given by this prognostics method,a novel cost driven predictive maintenance（CDPM） policy is proposed,which ensures the aircraft safety while minimizing the maintenance cost.The proposed policy is formally derived based on the trade-off between probabilities of occurrence of scheduled and unscheduled maintenance.A numerical case study simulating the maintenance process of an entire fleet of aircrafts is implemented.Under the condition of assuring the same safety level,the CDPM is compared in terms of cost with two other maintenance policies：scheduled maintenance and threshold based SHM maintenance.The comparison results show CDPM could lead to significant cost savings.展开更多
Due to the higher energy requirements of birds during winter, it is predicted that the activities of metabolic enzymes （e.g., citrate synthase, CS and cytochrome C oxidase, COX） should increase in tandem with increa...Due to the higher energy requirements of birds during winter, it is predicted that the activities of metabolic enzymes （e.g., citrate synthase, CS and cytochrome C oxidase, COX） should increase in tandem with increases in rates of energy expendi ture （e.g., basal metabolic rate, BMR）. However, there is mixed support for the hypothesis of enzymatic acclimatization. Fur thermore, there is little information about the effect of ambient temperature on energetics and tissue enzyme activity levels in passerines inhabiting seasonal Mediterranean environments. In this study we evaluated the interplay between BMR and enzyme activities of freshly caught individuals of the passerine Zonotrichia capensis in winter and summer in a Mediterranean environment from central Chile, and also in warm （30℃） and cold （15℃） labacclimated birds. The results revealed a lack of seasonal variation in BMR, thermal conductance and in the activity of CS and COX. However, we found higher BMR and lower thermal conductance in coldacclimated than in warmacclimated birds. Also, total CS activity was higher in the flight muscles of coldacclimated than in warmacclimated birds. We found also a significant correlation between BMR and total CS activity in pectoral muscle. Although some authors have suggested that BMR mainly depends on the metabolic intensity and mass of internal organs, our results revealed that skeletal muscles such as the flight muscles may also affect BMR. Finally, differences in the accli mation and acclimatization responses in Rufouscollared sparrows suggest that largescale oscillations in the physical environment might maintain the capacity for flexibility in thermogenic traits through generations .展开更多
A finite element analysis of stress intensity factors （KI） in clamped SE（T）c specimens （dog bone profile） is presented. A J-integral approach is used to calculate the values of stress intensity factors valid for...A finite element analysis of stress intensity factors （KI） in clamped SE（T）c specimens （dog bone profile） is presented. A J-integral approach is used to calculate the values of stress intensity factors valid for 0.125≤a/W≤0.625. A detailed comparison is made with the work of other researchers on rectangular specimens. Different boundary conditions are explored to best describe the real conditions in the laboratory. A sensitivity study is also presented to explore the effects of variation in specimen position in the grips of the testing machine. Finally the numerically calculated SIF is used to determine an FCGR curve for AISI Hll tool steel on SE（T）c specimens and compared with C（T） specimen of the same material.展开更多
There is relatively good evidence that non-human primates can communicate about objects and events in their envi- ronment in ways that allow recipients to draw inferences about the nature of the event experienced by t...There is relatively good evidence that non-human primates can communicate about objects and events in their envi- ronment in ways that allow recipients to draw inferences about the nature of the event experienced by the signaller. In some spe- cies, there is also evidence that the basic semantic units are not individual calls, but call sequences and the combinations gener- ated by them. These two findings are relevant to theories pertaining to the origins of human language because of the resemblances of these phenomena with linguistic reference and syntactic organisation. Until recently, however, most research efforts on the primate origins of human language have involved Old World species with comparatively few systematic studies on New World monkeys, which has prevented insights into the deeper phylogenetic roots and evolutionary origins of language-relevant capaci- ties. To address this, we review the older primate literature and very recent evidence for functionally referential communication and call combinations in New World primates. Within the existing literature there is ample evidence in both Callitrichids and Ce- bids for acoustically distinct call variants given to external disturbances that are accompanied by distinct behavioural responses. A general pattern is that one call type is typically produced in response to a wide range of general disturbances, often on the ground but also including inter-group encounters, while another call type is produced in response to a much narrower range of aerial threats. This pattern is already described for Old World monkeys and Prosimians, suggesting an early evolutionary origin. Second, recent work with black-fronted tiff monkeys has produced evidence for different alarm call sequences consisting of acoustically distinct call types. These sequences appear to encode several aspects of the predation event simultaneously, notably predator type and location. Since meaningful call sequences have already been described in Old World primates, we suggest that basic combi- natorial vocal communication has evolved in the primate lineage long before the advent of language. Moreover, it is possible that some of these communicative abilities have evolved even earlier, or independently, as there is comparable evidence in other taxonomic groups. We discuss these findings in an attempt to shed further light on the primate stock from which human language has arisen [Current Zoology 58 （5）： 680-697, 2012].展开更多
Objective:The main characteristics of diabetic nephropathy(DN)at the early stage are abnormal angiogenesis of glomerular endothelial cells(GECs)and macrophage infiltration.Galectin-3 plays a pivotal role in the pathog...Objective:The main characteristics of diabetic nephropathy(DN)at the early stage are abnormal angiogenesis of glomerular endothelial cells(GECs)and macrophage infiltration.Galectin-3 plays a pivotal role in the pathogenesis of DN via binding with its ligand,advanced glycation end products(AGEs).Catalpol,an iridoid glucoside extracted from Rehmannia glutinosa,has been found to ameliorate vascular inflammation,reduce endothelial permeability,and protect against endothelial damage in diabetic milieu.However,little is known about whether catalpol could exert an anti-angiogenesis and anti-inflammation effect induced by AGEs.Methods:Mouse GECs(mGECs)and RAW 264.7 macrophages were treated with different concentrations of AGEs(0,50,100,200 and 400μg/mL)for different time(0,6,12,24 and 48 h)to determine the optimal concentration of AGEs and treatment time.Cells were treated with catalpol(10μmol/L),GB1107(1μmol/L,galectin-3 inhibitor),PX-478(50μmol/L,HIF-1αinhibitor),adenovirus-green fluorescent protein(Ad-GFP)[3×10^(7)plaque-forming unit(PFU)/mL]or Ad-galectin-3-GFP(2×10^(8)PFU/mL),which was followed by incubation with 50μg/mL AGEs.The levels of galectin-3,vascular endothelial growth factor A(VEGFA)and pro-angiogenic factors angiopoietin-1(Ang-1),angiopoietin-2(Ang-2),tunica interna endothelial cell kinase-2(Tie-2)were detected by enzyme-linked immunosorbent assay(ELISA).Cell counting kit-8(CCK-8)assay was used to evaluate the proliferation of these cells.The expression levels of galectin-3,vascular endothelial growth factor receptor 1(VEGFR1),VEGFR2,and hypoxia-inducible factor-1α(HIF-1α)in mGECs and those of galectin-3 and HIF-1αin RAW 264.7 macrophages were detected by Western blotting and immunofluorescence(IF)staining.The rat DN model was established.Catalpol(100 mg/kg)or GB1107(10 mg/kg)was administered intragastrically once a day for 12 weeks.Ad-galectin-3-GFP(6×10^(7)PFU/mL,0.5 mL)or Ad-GFP(6×10^(6)PFU/mL,0.5 mL)was injected into the tail vein of rats 48 h before the sacrifice of the animals.The expression of galectin-3,VEGFR1,.VEGFR2,and HIF-1αin renal cortices was analyzed by Western blotting.The expression of galectin-3,F4/80(a macrophage biomarker),and CD34(an endothelium biomarker)in renal cortices was detected by IF staining,and collagen accumulation by Masson staining.Results:The expression levels of galectin-3 and VEGFA were significantly higher in mGECs and RAW 264.7 macrophages treated with 50μg/mL AGEs for 48 h than those in untreated cells.Catalpol and GB1107 could block the AGEs-induced proliferation of mGECs and RAW 264.7 macrophages.Over-expression of galectin-3 was found to reduce the inhibitory effect of catalpol on the proliferation of cells.Catalpol could significantly decrease the levels of Ang-1,Ang-2 and Tie-2 released by AGEs-treated mGECs,which could be reversed by over-expression of galectin-3.Catalpol could significantly inhibit AGEs-induced expression of galectin-3,HIF-1α,VEGFR1,and VEGFR2 in mGECs.The inhibitory effect of catalpol on galectin-3 in AGEs-treated mGECs was impaired by PX-478.Moreover,catalpol attenuated the AGEs-activated HIF-1α/galectin-3 pathway in RAW 264.7 macrophages,which was weakened by PX-478.Additionally,catalpol significantly inhibited the expression of galectin-3,macrophage infiltration,collagen accumulation,and angiogenesis in the kidney of diabetic rats.Over-expression of galectin-3 could antagonize these inhibitory effects of catalpol.Conclusion:Catalpol prevented the angiogenesis of mGECs and macrophage proliferation via inhibiting galectin-3.It could prevent the progression of diabetes-induced renal damage.展开更多
The most recent information on fascial tissue indicates that there are not fascial layers, but polyhedral microvacuoles of connective tissue, which connect the body systems and, by hosting specialized cells, permit se...The most recent information on fascial tissue indicates that there are not fascial layers, but polyhedral microvacuoles of connective tissue, which connect the body systems and, by hosting specialized cells, permit several functions, such as motor, nervous, vascular and visceral. These microvacuoles（a repetition of polyhedral units of connective fibrils） under internal or external tension change shape and can manage the movement variations, regulating different body functions and ensuring the maintenance of efficiency of the body systems. Their plasticity is based on perfect functional chaos： it is not possible to determine the motion vectors of the different fibrils, which differ in behavior and orientation; this strategy confers to the fascial continuum the maximum level of adaptability in response to the changing internal and external conditions of the cell. The present commentary deals with this concept, providing clinical examples of different disease patterns, providing contrary examples in which this adaptability does not occur, and lastly suggesting considerations for the approach to manipulative therapy of the fascial tissue. The fascial continuum is like a flock of birds flying together without a predetermined logic and maintaining their individuality at the same time.展开更多
基金supported by the Biogeography,Diversity and Conservation Lab of the University of Malaga,Project PID2021-124063OB-I00 of the Spanish Ministry of Science and Innovation and European Regional Development Fund(ERDF)and by the Leprosy Research Initiative Foundation(Grant#FP25\19)supported by a postdoctoral contract of the Plan Propio de Investigacion,Transferencia y Divulgacion Cientifica of the University of Malaga+7 种基金supported by MOPGA:Visiting Fellowship Program for early career researchers,Campus France,Francesupported by Gordon and Betty Moore Foundation through grant GBMF9258 to the Comunidad de Manejo de Fauna Silvestre en la Amazonia y en Latinoamerica(COMFAUNA)supported UK Research and Innovation’s Global Challenges Research Fund(UKRI GCRF)Trade,Development and the Environment Hub project(ES/S008160/1)supported by the joint NSF-NIH-NIFA Ecology and Evolution of Infectious Disease program(DEB#1911457)benefited from an‘Investissement d’Avenir’Grant managed by Agence Nationale de la Recherche,France(LABEX CEBA:ANR-10-LABX-25-01)supported by Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior—Brasil(CAPES)for a PNPD research fellowship.(88887.717863/2022-00)supported by a Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq)postdoctoral fellowship(150261/2023-3)supported by the Sustainable Landscapes and Livelihoods Programme.
文摘Background Leprosy remains a persistent public health challenge,where human-to-human transmission of Mycobacterium leprae via respiratory droplets is well established.In the tropical Americas,growing evidence implicates armadillos as important zoonotic reservoirs,particularly through direct contact during hunting and handling.However,such transmission has so far been considered rare and highly localised.This study provides a comprehensive spatial analysis of the role of armadillo hunting in human leprosy transmission,quantifying its contribution to disease prevalence and identifying geographic hotspots where interventions could be most effective.Methods Using Brazil’s 326,001 reported leprosy cases from 2013 to 2022,we applied a pathogeographical approach to explore transmission dynamics.We compiled data on 554 hunted armadillos across 175 municipalities and M.leprae prevalence in 376 armadillo individuals from 97 municipalities(mean prevalence=38.5%).These were used to build spatial models assessing hunting-related infection risk and integrated as a variable into a generalised linear model alongside socioeconomic,climatic,and environmental predictors to evaluate their effects on human leprosy prevalence.Results Key predictors of armadillo hunting included higher population density(P<0.001)and firearm availability(P<0.01).Infection in armadillos was negatively correlated with native habitat coverage(coefficient:−2.28;P<0.001),suggesting that environmental degradation can amplify infection risk.The armadillo-hunting infection risk variable—generated by combining armadillo hunting and infection favourability models—emerged as the second strongest predictor of human leprosy prevalence(coefficient:1.69;P<0.001),accounting for~25%of cases nationally and around 40%in deforestation hotspots.Additional positive predictors included greater precipitation seasonality(coefficient:0.82;P<0.001)and malnutrition(coefficient:0.01;P<0.001),while higher population density(coefficient:−0.64;P<0.001),natural habitat coverage(coefficient:−0.50;P<0.001)and socioeconomic status(coefficient:−0.47;P=0.013)were linked to reduced disease prevalence.Conclusions Armadillo hunting seems to play a more significant role in human leprosy transmission than previously recognised.To address this overlooked pathway,targeted interventions should focus on reducing unsafe and illegal hunting,improving communication around zoonotic risks,strengthening disease surveillance in high-risk areas,and conducting genetic studies to confirm wildlife-to-human transmission.Our findings highlight the importance of incorporating wildlife-associated transmission pathways into strategies to reduce disease prevalence and mitigate future outbreaks in tropical regions facing rapid environmental change and persistent poverty.
基金The National Natural Science Foundation of China,Grant/Award Number:82074104 and 8247143489the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences,Grant/Award Number:2022-I2M-2-002。
文摘Chronic obstructive pulmonary disease(COPD)is one of the leading causes of death and disability worldwide.Its complex etiology involves factors such as smoking,air pollution,genetic susceptibility,and social environment.With the accelerating global aging population and urbanization,the incidence and burden of COPD continue to rise.Current treatment strategies for COPD are relatively conservative,primarily focusing on bronchodilators,inhaled corticosteroids,and long-term oxygen therapy.Although these approaches can alleviate symptoms and slow disease progression to some ex-tent,they fail to effectively target the underlying mechanisms of the disease,leaving an unmet clinical need for more-effective therapies.This highlights the urgency of de-veloping innovative drugs that are both safe and efficacious to address the challenges in COPD treatment.As a traditional Chinese medicine with a long history,Colla corii asini has garnered significant attention for its diverse pharmacological effects and fa-vorable safety profile.Research has shown that Colla corii asini possesses multiple bio-logical activities,including hematopoiesis,nourishing the lungs,enhancing immunity,anti-infection,antiaging,antitumor,and antifatigue effects.Moreover,it has demon-strated potential in regulating oxidative stress,immune imbalance,and inflammatory responses.Recent evidence suggests that Colla corii asini may play a protective role in lung function through multitarget and multipathway mechanisms.Based on previ-ous research findings,this paper explores the potential therapeutic value of Colla corii asini in COPD treatment by addressing the current clinical management challenges and identifying potential therapeutic targets.It also integrates the pharmacological effects of Colla corii asini into a broader treatment context,providing new perspec-tives for comprehensive COPD management and laying the theoretical foundation for its modernization and innovative application.
基金financial support from the Chilean National Agency for Research and Development(ANID),National Doctorate No.21212028financial support from ANID,FONDECYT Regular Research Project No.1221793.
文摘Rubberized concrete is one of the most studied applications of discarded tires and offers a promising approach to developing materials with enhanced properties.The rubberized concrete mixture results in a reduced modulus of elasticity and a reduced compressive and tensile strength compared to traditional concrete.This study employs finite element simulations to investigate the elastic properties of rubberized mortar(RuM),considering the influence of inclusion stiffness and interfacial debonding.Different homogenization schemes,including Voigt,Reuss,and mean-field approaches,are implemented using DIGIMAT and ANSYS.Furthermore,the influence of the interfacial transition zone(ITZ)between mortar and rubber is analyzed by periodic homogenization.Subsequently,the influence of the ITZ is examined through a linear fracture analysis with the stress intensity factor as a key parameter,using the ANSYS SMART crack growth tool.Finally,a non-linear study in FEniCS is carried out to predict the strength of the composite material through a compression test.Comparisons with high density polyethylene(HDPE)and gravel inclusions show that increasing inclusion stiffness enhances compressive strength far more effectively than simply improving the mortar/rubber bond.Indeed,when the inclusions are much softer than the surrounding matrix,any benefit gained on the elastic modulus or strength from stronger interfacial adhesion becomes almost negligible.This study provide numerical evidence that tailoring the rubber’s intrinsic stiffness—not merely strengthening the rubber/mortar interface—is a decisive factor for improving the mechanical performance of RuM.
文摘In order to improve the knowledge of the precipitation mechanism in martensitic steels containing carbon,XRD synchrotron experiments were performed. Firstly, the influence of Ni,Co and Al were studied and it was found that the precipitation of iron carbides occurs in same way as in Fe-C steel. However, with the addition of molybdenum and chromium in same steels, XRD synchrotron investigations clearly showed alloyed carbides directly precipitate, thereby preventing the iron carbides formation.
基金The authors gratefully acknowledge the support from the Natural Sciences and Engineering Research Council of Canada(NSERC)2018–03889 through a Discovery Grant.Thanks to Mr.Adrien Lieurey(IMT-Mines Albi ICA-site Albi)for his involvement and fabrication of SLM parts.They would also like to express their gratitude to Aubert&Duval Co.,Dr.Alexandre Devaux,and Prof.Cormier for providing forged AD730™samples and discussions on the definition of the scope of the project.Special thanks to TWI Ltd.for carrying out the LFW of the samples.
文摘The continuous growth in the manufacture of aerospace components such as blisks has led to an increase in the application of different hybrid materials fabricating methods,and thus the requirements for joining and strengthening of dissimilar welds.According to this goal,selective laser melted(SLM)Inconel718 was joined with forged AD730^(TM)Nickel-based superalloy through linear friction welding(LFW)in this study.Microstructure variation,specifically with respect to secondary phases precipitation was investigated.The microhardness and strengthening mechanisms of the weldment were also studied.The precipitation(volume fraction and size of particles)at different regions of both sides of the weld line was characterized.Close to the weld line,the dissolution ofγ’/γ"and Laves phases and grain refinement occurred which reveals the effects of both compression strain and high temperature on recrystallization and high degree of elemental diffusion in the weld zone(WZ).It is shown that the size,volume fraction,and shape of secondary phases increased and changed(from spherical to long-striped for Laves particles)as we went from the WZ toward the base metal.However,the measured microhardness indicated that the strength of AD730^(TM)alloy depends significantly on the grain size,while strength in SLM Inconel 718 was dominated by shape(or size)and the presence of secondary phases(γ’/γ"and Laves).
基金supported by Grants DI 037.484/2013 and DI 37.370/2014 from the Dirección de Investigación,Vice-rectoría de Investigación y Estudios Avanzados,Pontificia Universidad Católica de Valparaíso,Chilesupported in part by Grant SA10I20005 from the National Fund for Health Research and Development(FONIS/MINSAL of CONICYT)
文摘This study analyze the relation between body composition, physical activity （PA）, and sex in Chilean children from rural and urban public educational institutions. The prevalence of obesity （according to BMI） was 30.88% in urban children and 28.93% in rural children. Central obesity presented mainly in the rural girls. Approximately 90% of the participants reported 〈7 h of PA/week, regardless of residential area. In addition, central fat was strongly associated with rural residence; the children reported lower PA levels, and they presented a higher prevalence of central fat. The results reflect the need to implement programs to improve PA conditions in the child urban-rural population.
基金supported by UT-INSA Program(2013)the support of the China Scholarship Council(CSC)
文摘Airframe maintenance is traditionally performed at scheduled maintenance stops.The decision to repair a fuselage panel is based on a fixed crack size threshold,which allows to ensure the aircraft safety until the next scheduled maintenance stop.With progress in sensor technology and data processing techniques,structural health monitoring（SHM） systems are increasingly being considered in the aviation industry.SHM systems track the aircraft health state continuously,leading to the possibility of planning maintenance based on an actual state of aircraft rather than on a fixed schedule.This paper builds upon a model-based prognostics framework that the authors developed in their previous work,which couples the Extended Kalman filter（EKF） with a firstorder perturbation（FOP） method.By using the information given by this prognostics method,a novel cost driven predictive maintenance（CDPM） policy is proposed,which ensures the aircraft safety while minimizing the maintenance cost.The proposed policy is formally derived based on the trade-off between probabilities of occurrence of scheduled and unscheduled maintenance.A numerical case study simulating the maintenance process of an entire fleet of aircrafts is implemented.Under the condition of assuring the same safety level,the CDPM is compared in terms of cost with two other maintenance policies：scheduled maintenance and threshold based SHM maintenance.The comparison results show CDPM could lead to significant cost savings.
文摘Due to the higher energy requirements of birds during winter, it is predicted that the activities of metabolic enzymes （e.g., citrate synthase, CS and cytochrome C oxidase, COX） should increase in tandem with increases in rates of energy expendi ture （e.g., basal metabolic rate, BMR）. However, there is mixed support for the hypothesis of enzymatic acclimatization. Fur thermore, there is little information about the effect of ambient temperature on energetics and tissue enzyme activity levels in passerines inhabiting seasonal Mediterranean environments. In this study we evaluated the interplay between BMR and enzyme activities of freshly caught individuals of the passerine Zonotrichia capensis in winter and summer in a Mediterranean environment from central Chile, and also in warm （30℃） and cold （15℃） labacclimated birds. The results revealed a lack of seasonal variation in BMR, thermal conductance and in the activity of CS and COX. However, we found higher BMR and lower thermal conductance in coldacclimated than in warmacclimated birds. Also, total CS activity was higher in the flight muscles of coldacclimated than in warmacclimated birds. We found also a significant correlation between BMR and total CS activity in pectoral muscle. Although some authors have suggested that BMR mainly depends on the metabolic intensity and mass of internal organs, our results revealed that skeletal muscles such as the flight muscles may also affect BMR. Finally, differences in the accli mation and acclimatization responses in Rufouscollared sparrows suggest that largescale oscillations in the physical environment might maintain the capacity for flexibility in thermogenic traits through generations .
文摘A finite element analysis of stress intensity factors （KI） in clamped SE（T）c specimens （dog bone profile） is presented. A J-integral approach is used to calculate the values of stress intensity factors valid for 0.125≤a/W≤0.625. A detailed comparison is made with the work of other researchers on rectangular specimens. Different boundary conditions are explored to best describe the real conditions in the laboratory. A sensitivity study is also presented to explore the effects of variation in specimen position in the grips of the testing machine. Finally the numerically calculated SIF is used to determine an FCGR curve for AISI Hll tool steel on SE（T）c specimens and compared with C（T） specimen of the same material.
文摘There is relatively good evidence that non-human primates can communicate about objects and events in their envi- ronment in ways that allow recipients to draw inferences about the nature of the event experienced by the signaller. In some spe- cies, there is also evidence that the basic semantic units are not individual calls, but call sequences and the combinations gener- ated by them. These two findings are relevant to theories pertaining to the origins of human language because of the resemblances of these phenomena with linguistic reference and syntactic organisation. Until recently, however, most research efforts on the primate origins of human language have involved Old World species with comparatively few systematic studies on New World monkeys, which has prevented insights into the deeper phylogenetic roots and evolutionary origins of language-relevant capaci- ties. To address this, we review the older primate literature and very recent evidence for functionally referential communication and call combinations in New World primates. Within the existing literature there is ample evidence in both Callitrichids and Ce- bids for acoustically distinct call variants given to external disturbances that are accompanied by distinct behavioural responses. A general pattern is that one call type is typically produced in response to a wide range of general disturbances, often on the ground but also including inter-group encounters, while another call type is produced in response to a much narrower range of aerial threats. This pattern is already described for Old World monkeys and Prosimians, suggesting an early evolutionary origin. Second, recent work with black-fronted tiff monkeys has produced evidence for different alarm call sequences consisting of acoustically distinct call types. These sequences appear to encode several aspects of the predation event simultaneously, notably predator type and location. Since meaningful call sequences have already been described in Old World primates, we suggest that basic combi- natorial vocal communication has evolved in the primate lineage long before the advent of language. Moreover, it is possible that some of these communicative abilities have evolved even earlier, or independently, as there is comparable evidence in other taxonomic groups. We discuss these findings in an attempt to shed further light on the primate stock from which human language has arisen [Current Zoology 58 （5）： 680-697, 2012].
基金supported by grants from the National Natural Science Foundation of China(No.81374029,No.81073111,No.81874359)Natural Science Foundation of the Higher Education Institutions of Jiangsu Province(No.18KJD360002)+1 种基金a Project Funded by Jiangsu Agri-animal Husbandry Vocational College(No.NSF2021CB04)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)(No.JKLPSE201604).
文摘Objective:The main characteristics of diabetic nephropathy(DN)at the early stage are abnormal angiogenesis of glomerular endothelial cells(GECs)and macrophage infiltration.Galectin-3 plays a pivotal role in the pathogenesis of DN via binding with its ligand,advanced glycation end products(AGEs).Catalpol,an iridoid glucoside extracted from Rehmannia glutinosa,has been found to ameliorate vascular inflammation,reduce endothelial permeability,and protect against endothelial damage in diabetic milieu.However,little is known about whether catalpol could exert an anti-angiogenesis and anti-inflammation effect induced by AGEs.Methods:Mouse GECs(mGECs)and RAW 264.7 macrophages were treated with different concentrations of AGEs(0,50,100,200 and 400μg/mL)for different time(0,6,12,24 and 48 h)to determine the optimal concentration of AGEs and treatment time.Cells were treated with catalpol(10μmol/L),GB1107(1μmol/L,galectin-3 inhibitor),PX-478(50μmol/L,HIF-1αinhibitor),adenovirus-green fluorescent protein(Ad-GFP)[3×10^(7)plaque-forming unit(PFU)/mL]or Ad-galectin-3-GFP(2×10^(8)PFU/mL),which was followed by incubation with 50μg/mL AGEs.The levels of galectin-3,vascular endothelial growth factor A(VEGFA)and pro-angiogenic factors angiopoietin-1(Ang-1),angiopoietin-2(Ang-2),tunica interna endothelial cell kinase-2(Tie-2)were detected by enzyme-linked immunosorbent assay(ELISA).Cell counting kit-8(CCK-8)assay was used to evaluate the proliferation of these cells.The expression levels of galectin-3,vascular endothelial growth factor receptor 1(VEGFR1),VEGFR2,and hypoxia-inducible factor-1α(HIF-1α)in mGECs and those of galectin-3 and HIF-1αin RAW 264.7 macrophages were detected by Western blotting and immunofluorescence(IF)staining.The rat DN model was established.Catalpol(100 mg/kg)or GB1107(10 mg/kg)was administered intragastrically once a day for 12 weeks.Ad-galectin-3-GFP(6×10^(7)PFU/mL,0.5 mL)or Ad-GFP(6×10^(6)PFU/mL,0.5 mL)was injected into the tail vein of rats 48 h before the sacrifice of the animals.The expression of galectin-3,VEGFR1,.VEGFR2,and HIF-1αin renal cortices was analyzed by Western blotting.The expression of galectin-3,F4/80(a macrophage biomarker),and CD34(an endothelium biomarker)in renal cortices was detected by IF staining,and collagen accumulation by Masson staining.Results:The expression levels of galectin-3 and VEGFA were significantly higher in mGECs and RAW 264.7 macrophages treated with 50μg/mL AGEs for 48 h than those in untreated cells.Catalpol and GB1107 could block the AGEs-induced proliferation of mGECs and RAW 264.7 macrophages.Over-expression of galectin-3 was found to reduce the inhibitory effect of catalpol on the proliferation of cells.Catalpol could significantly decrease the levels of Ang-1,Ang-2 and Tie-2 released by AGEs-treated mGECs,which could be reversed by over-expression of galectin-3.Catalpol could significantly inhibit AGEs-induced expression of galectin-3,HIF-1α,VEGFR1,and VEGFR2 in mGECs.The inhibitory effect of catalpol on galectin-3 in AGEs-treated mGECs was impaired by PX-478.Moreover,catalpol attenuated the AGEs-activated HIF-1α/galectin-3 pathway in RAW 264.7 macrophages,which was weakened by PX-478.Additionally,catalpol significantly inhibited the expression of galectin-3,macrophage infiltration,collagen accumulation,and angiogenesis in the kidney of diabetic rats.Over-expression of galectin-3 could antagonize these inhibitory effects of catalpol.Conclusion:Catalpol prevented the angiogenesis of mGECs and macrophage proliferation via inhibiting galectin-3.It could prevent the progression of diabetes-induced renal damage.
文摘The most recent information on fascial tissue indicates that there are not fascial layers, but polyhedral microvacuoles of connective tissue, which connect the body systems and, by hosting specialized cells, permit several functions, such as motor, nervous, vascular and visceral. These microvacuoles（a repetition of polyhedral units of connective fibrils） under internal or external tension change shape and can manage the movement variations, regulating different body functions and ensuring the maintenance of efficiency of the body systems. Their plasticity is based on perfect functional chaos： it is not possible to determine the motion vectors of the different fibrils, which differ in behavior and orientation; this strategy confers to the fascial continuum the maximum level of adaptability in response to the changing internal and external conditions of the cell. The present commentary deals with this concept, providing clinical examples of different disease patterns, providing contrary examples in which this adaptability does not occur, and lastly suggesting considerations for the approach to manipulative therapy of the fascial tissue. The fascial continuum is like a flock of birds flying together without a predetermined logic and maintaining their individuality at the same time.
