Mask image projection-based vat photopolymerization(MIP-VPP)offers advantages like low cost,high resolution,and a wide material range,making it popular in industry and education.Recently,MIP-VPP employing liquid cryst...Mask image projection-based vat photopolymerization(MIP-VPP)offers advantages like low cost,high resolution,and a wide material range,making it popular in industry and education.Recently,MIP-VPP employing liquid crystal displays(LCDs)has gained traction,increasingly replacing digital micromirror devices,particularly among hobbyists and in educational settings,and is now beginning to be used in industrial environments.However,LCD-based MIP-VPPsuffers from pronounced pixelated aliasing arising from LCD’s discrete image pixels and itsdirect-contact configuration in MIP-VPP machines,leading to rough surfaces on the 3D-printed parts.Here,we propose a vibration-assisted MIP-VPP method that utilizes a microscalevibration to uniformize the light intensity distribution of the LCD-based mask image on VPP’s building platform.By maintaining the same fabrication speed,our technique generates asmoother,non-pixelated mask image,reducing the roughness on flat surfaces and boundary segments of 3D-printed parts.Through light intensity modeling and simulation,we derived an optimal vibration pattern for LCD mask images,subsequently validated by experiments.We assessed the surface texture,boundary integrity,and dimensional accuracy of componentsproduced using the vibration-assisted approach.The notably smoother surfaces and improved boundary roughness enhance the printing quality of MIP-VPP,enabling its promisingapplications in sectors like the production of 3D-printed optical devices and others.展开更多
Background: Liquid pericarditis is a frequent cause of hospitalization in developing countries. Objective: of this study was to describe the etiological and evolutionary aspects of fluid pericarditis in pediatric card...Background: Liquid pericarditis is a frequent cause of hospitalization in developing countries. Objective: of this study was to describe the etiological and evolutionary aspects of fluid pericarditis in pediatric cardiology at ICA. Methods: This was a retrospective study of 42 cases of fluid pericarditis diagnosed among 202 children hospitalized over a five-year period (1st January 2009 to 31st December 2014). All patients with pericardial effusion were included in the study. Results: Prevalence was estimated at 20.8% of hospitalizations, sex ratio was 1.1 with a female predominance (52%) and the mean age at 9.2 years (11 days to 15 years). The etiologic varieties identified were: tuberculosis 22 cases, 52%, rheumatic pericarditis 6 cases or 14.3%, chronic parietal endocarditis 5 cases (11.9%), bacterial pericarditis with trivial germ 3 cases (7.1% 3 cases (7.1%), post-surgery syndrome 2 cases (4.8%), umbilical post-catheterization 1 case (2.4%). HIV serology was positive in 11.9% of cases. The progression was favorable in 55% of the cases with 10% of deaths. Conclusion: Fluid pericarditis in children is a severe condition that is clearly on the rise today, especially in immunocompromised patients. Optimal management of fluid pericarditis in children is the best guarantee to avoid short-term tamponade and in the medium term constriction.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
Tropical alpine ecosystems exhibit outstanding plant diversity and endemism while being particularly sensitive to the impacts of climate change.Although understanding spatiotemporal changes in plant species compositio...Tropical alpine ecosystems exhibit outstanding plant diversity and endemism while being particularly sensitive to the impacts of climate change.Although understanding spatiotemporal changes in plant species composition,richness and community structure along tropical alpine altitudinal gradients is of primary importance,both the functional and historical/biogeographic dimensions of vegetation diversity remain largely unexplored.We used Generalized Linear Models and multivariate analyses to assess changes in species,growth forms,and biogeographic groups richness and abundance,in response to habitat variables along an elevation gradient in seven summits(3800 to 4600 m asl)in the Venezuelan Andes,studied using the standardized approach of the GLORIA-Andes monitoring network.The habitat variables assessed were soil temperature(-10 cm),soil organic matter,slope inclination,and substrate cover.We found 113 species,representing72 genera,32 families,13 growth forms,and seven biogeographic origins,that included 25%of endemic elements.We observed richer vegetation,both in terms of species and growth forms,in summits with higher soil temperatures and higher SOM content,as well as higher biogeographic origin richness with increasing soil temperatures.The presence of holarctic elements increased toward higher elevations,while the occurrence of austral antarctic elements increased toward lower elevations.Our results indicate that biogeographic and functional approaches to vegetation diversity capture well the effect of abiotic filtering on community structuring in these tropical alpine environments.These findings constitute an important baseline for monitoring vegetation dynamics linked to climate change in the Venezuelan Andes by highlighting the functional and historical perspective on vegetation analyses,in contrast with more traditional approaches,based only on taxonomic species diversity.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
A complementary approach using Liquid Chromatographic-Mass Spectrometric analysis was proposed to characterize phenolic compounds from the methanol-water extracts of K.ivorensis A.Chev.Two High Performance Liquid Chro...A complementary approach using Liquid Chromatographic-Mass Spectrometric analysis was proposed to characterize phenolic compounds from the methanol-water extracts of K.ivorensis A.Chev.Two High Performance Liquid Chromatography(HPLC)complementary methods were used for the determination of phenolic compounds from the bark,sapwood and heartwood of K.ivorensis.Methods employed involved direct analysis after filtration at 0.20μm,using a RP C18 column and UV-VIS/ESI-FTMS detection.The methods used were different by their elution gradient and allowed analyzing the chemical composition of three parts of African mahogany extracts.In this study,22 phenolic compounds and derivatives from K.ivorensis were separated,determined or tentatively characterized for the first time based on their methanol/water/formic acid extract mass spectra.The difference of gradients eluted various compounds,8 were obtained with the first method and 14 with the second one.The main products were hydroxybenzoic acid and derivatives,resorcinol,esterified compounds,mannitol,quercetin and derivatives,dihydroxyflavan,and trihydroxyflavan.展开更多
Unfortunately,in the article The neuroprotective effect of traditional Chinese medicinal plantsdA critical review by Moreira et al.(Acta Pharmaceutica Sinica B 13(2023)3208-3237)some data have not been corrected in th...Unfortunately,in the article The neuroprotective effect of traditional Chinese medicinal plantsdA critical review by Moreira et al.(Acta Pharmaceutica Sinica B 13(2023)3208-3237)some data have not been corrected in the proofreading stage:Page 3225 e In the study by Lim et al.^(234).展开更多
The occurrence of seven endocrine-disrupting compounds(EDCs)in four urban rivers on the southern border of Mexico was studied in this work.The selected EDCs were 17b-estradiol(E2),estriol(E3),17aethinylestradiol(EE2),...The occurrence of seven endocrine-disrupting compounds(EDCs)in four urban rivers on the southern border of Mexico was studied in this work.The selected EDCs were 17b-estradiol(E2),estriol(E3),17aethinylestradiol(EE2),bisphenol A(BPA),bisphenol F(BPF),4-nonylphenol(4NP)and 4-tert-octylphenol(4TOP).Water samples from the Coatan,Texcuyuapan,Cahoacan,and Coatancito rivers were collected at three different sites on each river and processed by solid phase extraction(SPE).The samples were analyzed by gas chromatography triple quadrupole tandem mass spectrometry(GC-MS/MS)and compounds of interest were identified by dynamic mass reaction monitoring mode(dMRM).Among the target EDCs,E2,BPA,and 4NP were detected in all water samples,with BPA being the most abundant ranging from 4.22 up to 127.96 ng/L.Correlation tests showed significant positive associations between estrogens and BPA,as well as the correlation between alkylphenols and BPA,suggesting common origin emission sources,which were identified as discharges of untreated municipal wastewater.Finally,the estimation of RQ and EEQ values indicated that the presence of E2,E3,EE2,and BPA in all sampled points represents a high risk for aquatic life in these sites,mainly for Texcuyuapan River,where the aquatic organisms may be susceptible to endocrine disruption by chronic exposure to detected compounds.展开更多
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
Background Treeline ecotones of Mediterranean ecoregions have been affected by the increasing intensity and severity of droughts.Even though the effect of droughts on forest dynamics has been widely documented,knowled...Background Treeline ecotones of Mediterranean ecoregions have been affected by the increasing intensity and severity of droughts.Even though the effect of droughts on forest dynamics has been widely documented,knowledge is relatively scarce of how extreme climate episodes affect the hydraulic structure and,therefore,the phys-iology of woody plants.The Mediterranean Andes have experienced an uninterrupted period of drought since 2010,including an extremely dry year in 2019 with approximately 80%rainfall deficit.Here,we investigated shifts in wood anatomical and physiological traits of Kageneckia angustifolia,an endemic treeline species,in response to this drought period.Methods We evaluated the xylem plasticity of three K.angustifolia populations across their natural distribution(31–35°SL)based on anatomical(vessel structure and distribution)and physiological(intrinsic water-use efficiency)variables in the tree rings.We focused on the period 2000–2020 that corresponds to before the megadrought(2000–2007),(ii)megadrought(2008–2018)and(iii)hyperdrought(2019–2020).The variables were annualized and analyzed by linear mixed-effects models.Results Our results provide insights to the anatomical and physiological mechanisms underlying the resilience of treeline forests to persistent droughts in central Chile.We found that the extreme drought in 2019–2020 triggered shifts in vessel size and frequency that increased hydraulic safety.These significant shifts in vessel traits occurred in parallel with a decrease in pit aperture area and an increase in water-use efficiency,further increasing the resilience of K.angustifolia to extreme drought stress.Conclusions Our results revealed coordinated shifts in vessel size and frequency and water-use efficiency in response to the megadrought,thereby reducing vulnerability to hydraulic failure.The apparent resilience of K.angustifolia to extreme droughts suggests that this adaptation to drought stress may increase its ability to tolerate novel climatic conditions of treeline environments of the Mediterranean Andes,although it is not clear whether these adaptations will be sufficient to persist in scenarios that predict intensification of climate stress.Finally,our results provide empirical evidence that integrating wood anatomical and physiological traits facilitates the understanding of resilience mechanisms that treeline forests develop in the face of increasing drought stress.展开更多
For more than 7 years,our research work is focussed upon the electrical behavior of carbon fiber reinforced composites.Effectively carbon/polymeric matrix laminates can be considered as an electri-cally conductive net...For more than 7 years,our research work is focussed upon the electrical behavior of carbon fiber reinforced composites.Effectively carbon/polymeric matrix laminates can be considered as an electri-cally conductive network(i.e.carbon fibers)embedded in an insulat-ing medium(i.e.the polymeric matrix).Consequently,from an electrical point of view laminated composites have been modelled owing to combinations of electrical resistances(i.e.fibers themselves and the contact points between the fibers)and capacitances(i.e.polymeric matrix).During their manufacturing,composite material such as thermoset matrix composites for instance,undergo various changes in their physical(including electrical and mechanical)prop-erties and in their geometrical characteristics.In fact,in the case of manufacturing processes such as oven curing(vacuum bag),auto-clave curing or heating plate press,beside the chemo-rheologi-cal changes,the laminated parts are the place of a compaction phenomenon inducing changes in fiber volume fraction and thick-nesses.The idea developed in this paper is that since the carbon/polymeric matrix laminate can be considered as an electrical network,it can then be view and used as a sensor for following the material state during the manufacturing process enabling thus defects to be detected and this without any additional sensing material or device.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
Xeroderma pigmentosum （XP） is a group of genetic disorders caused by mutations of XP-associated genes, resulting in impairment of DNA repair. XP patients frequently exhibit neurological degeneration, but the underly...Xeroderma pigmentosum （XP） is a group of genetic disorders caused by mutations of XP-associated genes, resulting in impairment of DNA repair. XP patients frequently exhibit neurological degeneration, but the underlying mechanism is unknown, in part due to lack of proper disease models. Here, we generated patientspecific induced pluripotent stem cells （iPSCs） harboring mutations in five different XP genes including XPA, XPB, XPC, XPG, and XPV. These iPSCs were further differentiated to neural cells, and their susceptibility to DNA damage stress was investigated. Mutation of XPA in either neural stem cells （NSCs） or neurons resulted in severe DNA damage repair defects, and these neural cells with mutant XPA were hyper-sensitive to DNA damage-induced apoptosis. Thus, XP-mutant neural cells represent valuable tools to clari the molecular mechanisms of neurological abnormalities in the XP patients.展开更多
The next US president will be elected in November 2008. Since the relative stabilization of war in Iraq, the economy has become the national priority of the 2008 US election. In their campaign efforts, the Democrats h...The next US president will be elected in November 2008. Since the relative stabilization of war in Iraq, the economy has become the national priority of the 2008 US election. In their campaign efforts, the Democrats have enjoyed greater momentum than the Republicans, in terms of polls, fund-raising and corporate support. After the Bush era, the next president will seek to restore America＇s leadership and to engage in multilateralism. Since the 1990s, China has been the most rapidly-growing US export destination. In terms of US-Shinese trade and investment, the next president, ira Democrat, will, among other issues, review trade agreements and has pledged to co-sponsor legislation that would allow US companies to seek anti-dumping duties on Chinese imports based on the perceived undervaluation of the Chinese currency. If a Republican, the next president will support global integration and oppose protectionist measures. The Democratic Congress is likely to oppose Republican policies in general and free trade policies in particular. Both scenarios imply increasing pressure on US-Chinese trade and investment relationships. Because these two nations now account for almost half of global growth, the state of the futureUS-Chinese bilateral relationship has worldwide implications.展开更多
Piezoelectric resonant de-icing systems are attracting great interest.This paper aims to assess the implementation of these systems at the aircraft level.The article begins with the model to compute the power requirem...Piezoelectric resonant de-icing systems are attracting great interest.This paper aims to assess the implementation of these systems at the aircraft level.The article begins with the model to compute the power requirement of a piezoelectric resonant de-icing system sized from the prototype detailed in Part 1/2 of this article.Then the mass,drag,and fuel consumption of this system and the subcomponents needed for its implementation are assessed.The features of a piezoelectric resonant de-icing system are finally computed for aircraft similar to Airbus A320 aircraft and aircraft of different categories(Boeing 787,ATR 72 and TBM 900)and compared with the existing thermal and mechanical ice protection systems.A sensitivity analysis of the main key sizing parameters of the piezoelectric de-icing system is also performed to identify the main axes of improvement for this technology.The study shows the potential of such ice protection systems.In particular,for the realistic input parameters chosen in this work,the electro-mechanical solution can provide a 54% reduction in terms of mass and a 92% reduction in terms of power consumption for an A320 aircraft architecture,leading to a 74% decrease in the associated fuel consumption compared to the actual air bleed system.展开更多
文摘Mask image projection-based vat photopolymerization(MIP-VPP)offers advantages like low cost,high resolution,and a wide material range,making it popular in industry and education.Recently,MIP-VPP employing liquid crystal displays(LCDs)has gained traction,increasingly replacing digital micromirror devices,particularly among hobbyists and in educational settings,and is now beginning to be used in industrial environments.However,LCD-based MIP-VPPsuffers from pronounced pixelated aliasing arising from LCD’s discrete image pixels and itsdirect-contact configuration in MIP-VPP machines,leading to rough surfaces on the 3D-printed parts.Here,we propose a vibration-assisted MIP-VPP method that utilizes a microscalevibration to uniformize the light intensity distribution of the LCD-based mask image on VPP’s building platform.By maintaining the same fabrication speed,our technique generates asmoother,non-pixelated mask image,reducing the roughness on flat surfaces and boundary segments of 3D-printed parts.Through light intensity modeling and simulation,we derived an optimal vibration pattern for LCD mask images,subsequently validated by experiments.We assessed the surface texture,boundary integrity,and dimensional accuracy of componentsproduced using the vibration-assisted approach.The notably smoother surfaces and improved boundary roughness enhance the printing quality of MIP-VPP,enabling its promisingapplications in sectors like the production of 3D-printed optical devices and others.
文摘Background: Liquid pericarditis is a frequent cause of hospitalization in developing countries. Objective: of this study was to describe the etiological and evolutionary aspects of fluid pericarditis in pediatric cardiology at ICA. Methods: This was a retrospective study of 42 cases of fluid pericarditis diagnosed among 202 children hospitalized over a five-year period (1st January 2009 to 31st December 2014). All patients with pericardial effusion were included in the study. Results: Prevalence was estimated at 20.8% of hospitalizations, sex ratio was 1.1 with a female predominance (52%) and the mean age at 9.2 years (11 days to 15 years). The etiologic varieties identified were: tuberculosis 22 cases, 52%, rheumatic pericarditis 6 cases or 14.3%, chronic parietal endocarditis 5 cases (11.9%), bacterial pericarditis with trivial germ 3 cases (7.1% 3 cases (7.1%), post-surgery syndrome 2 cases (4.8%), umbilical post-catheterization 1 case (2.4%). HIV serology was positive in 11.9% of cases. The progression was favorable in 55% of the cases with 10% of deaths. Conclusion: Fluid pericarditis in children is a severe condition that is clearly on the rise today, especially in immunocompromised patients. Optimal management of fluid pericarditis in children is the best guarantee to avoid short-term tamponade and in the medium term constriction.
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the financial support to the GLORIA-Andes network in Venezuela of CONDESAN and the Swiss Development Agency(SDC)The present synthesis analysis was financed by the Adaptation at Altitude Program(CONDESAN-SDC)。
文摘Tropical alpine ecosystems exhibit outstanding plant diversity and endemism while being particularly sensitive to the impacts of climate change.Although understanding spatiotemporal changes in plant species composition,richness and community structure along tropical alpine altitudinal gradients is of primary importance,both the functional and historical/biogeographic dimensions of vegetation diversity remain largely unexplored.We used Generalized Linear Models and multivariate analyses to assess changes in species,growth forms,and biogeographic groups richness and abundance,in response to habitat variables along an elevation gradient in seven summits(3800 to 4600 m asl)in the Venezuelan Andes,studied using the standardized approach of the GLORIA-Andes monitoring network.The habitat variables assessed were soil temperature(-10 cm),soil organic matter,slope inclination,and substrate cover.We found 113 species,representing72 genera,32 families,13 growth forms,and seven biogeographic origins,that included 25%of endemic elements.We observed richer vegetation,both in terms of species and growth forms,in summits with higher soil temperatures and higher SOM content,as well as higher biogeographic origin richness with increasing soil temperatures.The presence of holarctic elements increased toward higher elevations,while the occurrence of austral antarctic elements increased toward lower elevations.Our results indicate that biogeographic and functional approaches to vegetation diversity capture well the effect of abiotic filtering on community structuring in these tropical alpine environments.These findings constitute an important baseline for monitoring vegetation dynamics linked to climate change in the Venezuelan Andes by highlighting the functional and historical perspective on vegetation analyses,in contrast with more traditional approaches,based only on taxonomic species diversity.
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A complementary approach using Liquid Chromatographic-Mass Spectrometric analysis was proposed to characterize phenolic compounds from the methanol-water extracts of K.ivorensis A.Chev.Two High Performance Liquid Chromatography(HPLC)complementary methods were used for the determination of phenolic compounds from the bark,sapwood and heartwood of K.ivorensis.Methods employed involved direct analysis after filtration at 0.20μm,using a RP C18 column and UV-VIS/ESI-FTMS detection.The methods used were different by their elution gradient and allowed analyzing the chemical composition of three parts of African mahogany extracts.In this study,22 phenolic compounds and derivatives from K.ivorensis were separated,determined or tentatively characterized for the first time based on their methanol/water/formic acid extract mass spectra.The difference of gradients eluted various compounds,8 were obtained with the first method and 14 with the second one.The main products were hydroxybenzoic acid and derivatives,resorcinol,esterified compounds,mannitol,quercetin and derivatives,dihydroxyflavan,and trihydroxyflavan.
文摘Unfortunately,in the article The neuroprotective effect of traditional Chinese medicinal plantsdA critical review by Moreira et al.(Acta Pharmaceutica Sinica B 13(2023)3208-3237)some data have not been corrected in the proofreading stage:Page 3225 e In the study by Lim et al.^(234).
基金the Universidad Politecnica de Tapachula(UPTap)and Centro de Investigaciones Químicas,Universidad Autonoma del Estado de Morelos for all facilities granted to carry out this work.The first author Lopez-Velazquez(CVU 736037)thanks the Consejo Nacional de HumanidadesCiencias y Tecnologías(CONAHCYT)and the program Estancias Posdoctorales por Mexico-Continuidad 2022(1)for the funding granted.We also thank Kevin G.Duque Olivera for his support during the sampling seasons.
文摘The occurrence of seven endocrine-disrupting compounds(EDCs)in four urban rivers on the southern border of Mexico was studied in this work.The selected EDCs were 17b-estradiol(E2),estriol(E3),17aethinylestradiol(EE2),bisphenol A(BPA),bisphenol F(BPF),4-nonylphenol(4NP)and 4-tert-octylphenol(4TOP).Water samples from the Coatan,Texcuyuapan,Cahoacan,and Coatancito rivers were collected at three different sites on each river and processed by solid phase extraction(SPE).The samples were analyzed by gas chromatography triple quadrupole tandem mass spectrometry(GC-MS/MS)and compounds of interest were identified by dynamic mass reaction monitoring mode(dMRM).Among the target EDCs,E2,BPA,and 4NP were detected in all water samples,with BPA being the most abundant ranging from 4.22 up to 127.96 ng/L.Correlation tests showed significant positive associations between estrogens and BPA,as well as the correlation between alkylphenols and BPA,suggesting common origin emission sources,which were identified as discharges of untreated municipal wastewater.Finally,the estimation of RQ and EEQ values indicated that the presence of E2,E3,EE2,and BPA in all sampled points represents a high risk for aquatic life in these sites,mainly for Texcuyuapan River,where the aquatic organisms may be susceptible to endocrine disruption by chronic exposure to detected compounds.
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FONDECYT Postdoctorado 3200765AVG to Fondecyt Regular 1221701+1 种基金DC to FONDECYT Project 1201347supported by a fellowship from the Fundacao de AmparoàPesquisa do Estado do Sao Paulo(FAPESP,grants 2023/07753-6)
文摘Background Treeline ecotones of Mediterranean ecoregions have been affected by the increasing intensity and severity of droughts.Even though the effect of droughts on forest dynamics has been widely documented,knowledge is relatively scarce of how extreme climate episodes affect the hydraulic structure and,therefore,the phys-iology of woody plants.The Mediterranean Andes have experienced an uninterrupted period of drought since 2010,including an extremely dry year in 2019 with approximately 80%rainfall deficit.Here,we investigated shifts in wood anatomical and physiological traits of Kageneckia angustifolia,an endemic treeline species,in response to this drought period.Methods We evaluated the xylem plasticity of three K.angustifolia populations across their natural distribution(31–35°SL)based on anatomical(vessel structure and distribution)and physiological(intrinsic water-use efficiency)variables in the tree rings.We focused on the period 2000–2020 that corresponds to before the megadrought(2000–2007),(ii)megadrought(2008–2018)and(iii)hyperdrought(2019–2020).The variables were annualized and analyzed by linear mixed-effects models.Results Our results provide insights to the anatomical and physiological mechanisms underlying the resilience of treeline forests to persistent droughts in central Chile.We found that the extreme drought in 2019–2020 triggered shifts in vessel size and frequency that increased hydraulic safety.These significant shifts in vessel traits occurred in parallel with a decrease in pit aperture area and an increase in water-use efficiency,further increasing the resilience of K.angustifolia to extreme drought stress.Conclusions Our results revealed coordinated shifts in vessel size and frequency and water-use efficiency in response to the megadrought,thereby reducing vulnerability to hydraulic failure.The apparent resilience of K.angustifolia to extreme droughts suggests that this adaptation to drought stress may increase its ability to tolerate novel climatic conditions of treeline environments of the Mediterranean Andes,although it is not clear whether these adaptations will be sufficient to persist in scenarios that predict intensification of climate stress.Finally,our results provide empirical evidence that integrating wood anatomical and physiological traits facilitates the understanding of resilience mechanisms that treeline forests develop in the face of increasing drought stress.
文摘For more than 7 years,our research work is focussed upon the electrical behavior of carbon fiber reinforced composites.Effectively carbon/polymeric matrix laminates can be considered as an electri-cally conductive network(i.e.carbon fibers)embedded in an insulat-ing medium(i.e.the polymeric matrix).Consequently,from an electrical point of view laminated composites have been modelled owing to combinations of electrical resistances(i.e.fibers themselves and the contact points between the fibers)and capacitances(i.e.polymeric matrix).During their manufacturing,composite material such as thermoset matrix composites for instance,undergo various changes in their physical(including electrical and mechanical)prop-erties and in their geometrical characteristics.In fact,in the case of manufacturing processes such as oven curing(vacuum bag),auto-clave curing or heating plate press,beside the chemo-rheologi-cal changes,the laminated parts are the place of a compaction phenomenon inducing changes in fiber volume fraction and thick-nesses.The idea developed in this paper is that since the carbon/polymeric matrix laminate can be considered as an electrical network,it can then be view and used as a sensor for following the material state during the manufacturing process enabling thus defects to be detected and this without any additional sensing material or device.
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.
基金This work was supported by National Basic Research Program （973 Program） （Nos. 2015CB964800 and 2014CB910503）, the Strategic Priority Research Program of the Chinese Academy of Sciences （XDA01020312）, National High Technology Research and Development Program of China （2015AA020307）, National Natural Science Foundation of China （Grant Nos. 81330008, 31222039, 31201111, 81371342, 81300261, 81300677, 81271266, 81471414, 81422017, and 81401159）, Beijing Natural Science Foundation （7141005 5142016）, Program of Beijing Municipal Science and Technology Commission （Z151100003915072）, Key Research Program of the Chinese Academy of Sciences （KJZDEW-TZ-L05）, the Thousand Young Talents program of China, National Laboratory of Biomacromolecules （012kf02, 2013kf05, 2013kf11, 2014kf02, 2015kfl 0）. J.C.I.B. was supported by UCAM, the G. Harold and Leila Y. Mathers Charitable Foundation, the Leona M. and Harry B. Helmsley Charitable Trust （2012-PG-MED002） and the Moxie Foundation.
文摘Xeroderma pigmentosum （XP） is a group of genetic disorders caused by mutations of XP-associated genes, resulting in impairment of DNA repair. XP patients frequently exhibit neurological degeneration, but the underlying mechanism is unknown, in part due to lack of proper disease models. Here, we generated patientspecific induced pluripotent stem cells （iPSCs） harboring mutations in five different XP genes including XPA, XPB, XPC, XPG, and XPV. These iPSCs were further differentiated to neural cells, and their susceptibility to DNA damage stress was investigated. Mutation of XPA in either neural stem cells （NSCs） or neurons resulted in severe DNA damage repair defects, and these neural cells with mutant XPA were hyper-sensitive to DNA damage-induced apoptosis. Thus, XP-mutant neural cells represent valuable tools to clari the molecular mechanisms of neurological abnormalities in the XP patients.
文摘The next US president will be elected in November 2008. Since the relative stabilization of war in Iraq, the economy has become the national priority of the 2008 US election. In their campaign efforts, the Democrats have enjoyed greater momentum than the Republicans, in terms of polls, fund-raising and corporate support. After the Bush era, the next president will seek to restore America＇s leadership and to engage in multilateralism. Since the 1990s, China has been the most rapidly-growing US export destination. In terms of US-Shinese trade and investment, the next president, ira Democrat, will, among other issues, review trade agreements and has pledged to co-sponsor legislation that would allow US companies to seek anti-dumping duties on Chinese imports based on the perceived undervaluation of the Chinese currency. If a Republican, the next president will support global integration and oppose protectionist measures. The Democratic Congress is likely to oppose Republican policies in general and free trade policies in particular. Both scenarios imply increasing pressure on US-Chinese trade and investment relationships. Because these two nations now account for almost half of global growth, the state of the futureUS-Chinese bilateral relationship has worldwide implications.
文摘Piezoelectric resonant de-icing systems are attracting great interest.This paper aims to assess the implementation of these systems at the aircraft level.The article begins with the model to compute the power requirement of a piezoelectric resonant de-icing system sized from the prototype detailed in Part 1/2 of this article.Then the mass,drag,and fuel consumption of this system and the subcomponents needed for its implementation are assessed.The features of a piezoelectric resonant de-icing system are finally computed for aircraft similar to Airbus A320 aircraft and aircraft of different categories(Boeing 787,ATR 72 and TBM 900)and compared with the existing thermal and mechanical ice protection systems.A sensitivity analysis of the main key sizing parameters of the piezoelectric de-icing system is also performed to identify the main axes of improvement for this technology.The study shows the potential of such ice protection systems.In particular,for the realistic input parameters chosen in this work,the electro-mechanical solution can provide a 54% reduction in terms of mass and a 92% reduction in terms of power consumption for an A320 aircraft architecture,leading to a 74% decrease in the associated fuel consumption compared to the actual air bleed system.
