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fracture Loci in Sheet Metal forming: A Review

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1415-1425页

作者： M.Beatriz silva Kerim Isik A.Erman Tekkaya Paulo A.f.Martins IDMEC Instituto Superior Técnico Universidade de Lisboa Institute of forming Technology and Lightweight Construction Technical University of Dortmund

fracture in sheet metal forming usually occurs as ductile fracture, rarely as brittle fracture, at the operating temperatures and rates of loading that are typical of real processes in two different modes：（1） tensile and（2） in-plane shear（respectively, the same as modes I and II of fracture mechanics）. The circumstances under which each mode will occur are identified in terms of plastic flow and ductile damage by means of an analytical approach to characterize fracture loci under plane stress conditions that takes anisotropy into consideration. fracture loci was characterized by means of the fracture forming limit line and by the shear fracture forming limit line in the fracture forming limit diagram. Experiments were performed with single point incremental forming and double-notched test specimens loaded in tension, torsion and in-plane shear give support to the presentation and allow determining the fracture loci of AA1050-H111 aluminium sheets with1 mm thickness. The relation between fracture toughness and the fracture forming limits was also investigated by comparing experimental values of the strains at fracture obtained from a truncated conical part produced by single point incremental forming and from double-notched test specimens loaded in tension.

关键词： Sheet forming fracture fracture forming limit diagram

Particulate matter geochemistry of a highly industrialized region in the Caribbean:Basis for future toxicological studies

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Geoscience frontiers 2022年第1期13卷 376-387页

作者： Luis f.O.silva Ismael L.Schneider Paulo Artaxo Yuleisy Núñez-Blanco Diana Pinto Érico M.M.flores Leandro Gómez-Plata Omar Ramírez Guilherme L.Dotto department of Civil and Environmental Universidad de la CostaCUCCalle 58#55–66BarranquillaAtlánticoColombia department of Applied Physics Institute of PhysicsUniversity of São PauloBrazil department of Chemistry Universidade Federal de Santa MariaRSBrazil Universidad Militar Nueva Granada(UMNG) Faculty of EngineeringEnvironmental EngineeringKm 2 Cajicá-ZipaquiráColombia Chemical Engineering department Federal University of Santa Maria-UFSM1000Roraima Avenue97105-900 Santa MariaRSBrazil

Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health *** this work,we studied the concentrations of PM_(10) and PM_(2.5) sources in an industrial and port urban area in the Caribbean region of *** samples were collected within 48-h periods between April and October 2018 by using a Partisol 2000 i-D *** geochemical characterization was performed by X-ray fluorescence(XRf)***,ionic species and black carbon(BC)were quantified by ion chromatography and reflectance spectroscopy,*** the Positive Matrix factorization(PMf)receptor model,the contributions of PM sources were *** average concentration of PM_(10) was 46.6±16.2μg/m^(3),with high concentrations of Cl and *** PM_(2.5),the average concentration was 12.0±3.2μg/m^(3),and the most abundant components were BC,S,and *** receptor model identified five sources for PM_(10) and PM_(2.5).for both fractions,the contributions of marine sea spray,re-suspended soil,and vehicular traffic were *** addition,PM_(2.5) included two mixed sources were found to be fuel oil combustion with fertilizer industry emissions,and secondary aerosol sources with building construction ***,PM_(10) was found to also include building construction emissions with re-suspended soil,and metallurgical industry *** obtained geochemical atmospheric results are important for the implementation of strategies for the continuous improvement of the air quality of the Caribbean region.

关键词： Urban air pollution Particulate matter Geochemical composition Aerosol source apportionment Receptor models PMf

Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries

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npj Computational Materials 2020年第1期6卷 76-88页

作者： Reza darvishi Kamachali Alisson Kwiatkowski da silva Eunan McEniry Dirk Ponge Baptiste Gault Jörg Neugebauer Dierk Raabe federal Institute for Materials Research and Testing(BAM) Unter den Eichen 8712205 BerlinGermany Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Straße 140237 DüsseldorfGermany department of Materials Royal School of MinesImperial CollegePrince Consort RoadLondon SW72BPUK

Segregation to grain boundaries affects their cohesion,corrosion,and embrittlement and plays a critical role in heterogeneous *** order to quantitatively study segregation and low-dimensional phase separation at grain boundaries,here,we apply a density-based phase-field *** current model describes the grain-boundary thermodynamic properties based on available bulk thermodynamic data,while the grain-boundary-density profile is obtained using atomistic *** benchmark the performance of the model,Mn grain-boundary segregation in the fe–Mn system is studied.3D simulation results are compared against atom probe tomography measurements conducted for three alloy *** show that a continuous increase in the alloy composition results in a discontinuous jump in the segregation *** jump corresponds to a spinodal phase separation at grain *** alloy compositions above the jump,we reveal an interfacial transient spinodal phase *** transient spinodal phenomenon opens opportunities for knowledge-based microstructure design through the chemical manipulation of grain *** proposed density-based model provides a powerful tool to study thermodynamics and kinetics of segregation and phase changes at grain boundaries.

关键词： grain alloy separation

Maternal hyperthyroidism increases the synthesis activity and the osteogenic markers expression of calvarial osteoblasts from offspring in a murine model

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BIOCELL 2023年第2期47卷 423-430页

作者： fABIANA ROCHA ARAÚJO BRUNO MACHADO BERTASSOLI ISABELLA CRISTINA SOUZA fÉLIX DOUGLAS MARINHO ABREU NATÁLIA MELO OCARINO AMANda MARIA SENA REIS JUNEO fREITAS silva ROGÉRIA SERAKIdeS Núcleo de Células Tronco e Terapia Celular Animal(NCT-TCA) Veterinay SchoolUniversidade Federal de Minas GeraisBelo HorizonteMinas Gerais31270-901Brasil Universidade de Uberaba(UNIUBE) UberabaMinas Gerais38065-300Brasil Instituto de Ciências Biológicas Universidade Federal de Minas GeraisBelo HorizonteMinas Gerais31270-901Brasil Universidade Estadual de Santa Cruz Campus Soane Nazare de AndradeIlheusBahiaBrasil

To evaluate the characteristics and synthesis activity of osteoblasts extracted from the calvaria of offspring of rats exposed to maternal *** adult Wistar rats were divided into two groups,one control and one treated with daily administration of L-thyroxine by an orogastric tube(50μg/animal/day)during *** days after delivery and confirmation of the mothers’hyperthyroidism,the offspring were euthanized for the extraction of osteoblasts from the *** 7,14,and 21 days,proliferation activity was assessed using MTT assay,while alkaline phosphatase(ALP)activity was assessed by the BCIP/NBT *** 21 days,the total area of the mineralized matrix stained by von Kossa was evaluated by *** expression of gene transcripts for Runx2,Bmp2,fgfr1,collagen type 1(Col1),osteocalcin(Oc),and osteopontin(Op)were evaluated by real-time *** were compared using the Student’s *** activity was significantly higher at 14 and 21 days in cultures of osteoblasts extracted from offspring exposed to maternal hyperthyroidism,while MTT conversion was significantly lower at 21 days in this *** cultures of neonates exposed to maternal hyperthyroidism also showed a larger total area of mineralized matrix and greater expression of gene transcripts for Oc and *** hyperthyroidism increases the activity of matrix synthesis,alkaline phosphatase activity,and expression of gene transcripts for osteocalcin and osteopontin in the osteoblasts,extracted from the calvaria of the offspring,which may be one of the mechanisms of premature fusion of cranial sutures.

关键词： Craniosynostosis Intramembranous growth Ossification Rat Thyroid dysfunction

Comparative carbon emission assessments of recycled and natural aggregate concrete: Environmental influence of cement content

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Geoscience frontiers 2021年第6期12卷 66-75页

作者： Marian Sabǎu dan V.Bompa Luis f.O.silva department of Civil and Environmental Engineering Universidad de la Costa080020 BarranquillaColombia department of Civil and Environmental Engineering University of SurreyGuildford GU27XHUK departamento de Ingeniería Civil y Arquitectura Universidad de LimaAvenida Javier Prado Este 4600Santiago de Surco 1503Peru

This work examines the environmental and geochemical impact of recycled aggregate concrete production with properties representative for structural *** environmental influence of cement content,aggregate production,transportation,and waste landfilling is analysed by undertaking a life cycle assessment and considering a life cycle inventory largely specific for the *** obtain a detailed insight into the optimum life cycle parameters,a sensitivity study is carried out in which supplementary cementitious materials,different values of natural-to-recycled aggregate content ratio and case-specific transportation distances were *** results show that carbon emissions were between 323 and 332 kgCO_(2)e per cubic metre of cement only natural aggregate *** values can be reduced by up to 17%by replacing 25%of the cement with fly *** contrast,carbon emissions can increase when natural coarse aggregates are replaced by recycled aggregates in proportions of 50%and 100%,and transportation is not included in ***,the concrete with 50%recycled aggregate presented lower increase,only 0.3%and 3.4%for normal and high strength concrete,*** some cases,the relative contribution of transportation to the total carbon emissions increased when cement was replaced by fly ash in proportions of 25%,and case-specific transportation distances were *** absolute values,the concrete mixes with 100%recycled aggregates and 25%fly ash had lower carbon emissions than concrete with cement and natural aggregates *** environmental benefits can be obtained when the transportation distances of fly ash are relatively short(15–25 km)and the cement replacement by fly ash is equal or higher than 25%,considering that the mechanical properties are adequate for practical *** observations from this paper show that recycled aggregate concrete with strength characteristics representative for structural members can have lowe

关键词： Life cycle assessment Recycled aggregate Natural aggregate Transportation distance OpenLCA

Lipoprotein(a)and Ultrasensitive C-Reactive Protein in Overweight Adolescents

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Health 2014年第17期6卷 2349-2355页

作者： Débora Larissa Rufino Alves Camilla Ribeiro Lima de farias Ivelise f.A.f.da Costa Monica Oliveira da silva Simoes Carla Campos Muniz Medeiros danielle franklin de Carvalho department of Nursing State University of ParaibaCampina GrandeBrazil Graduate Program in Public Health Centre for Epidemiological ResearchState University of ParaibaCampina GrandeBrazil department of Pharmacy Graduate Program in Public HealthCentre for Epidemiological ResearchState University of ParaibaCampina GrandeBrazil department of Nursing Graduate Program in Public HealthCentre for Epidemiological ResearchState University of ParaibaCampina GrandeBrazil

Introduction: The more intense and early development of obesity, the greater the risk of persistence and severity of comorbidities, such as cardiovascular disease. There is evidence that high serum concentrations of lipoprotein (a) [Lp (a)] and C-reactive protein (CRP) are associated with increased risk of cardiovascular diseases. Objectives: To verify the change in the levels of Lp (a) and ultrasensitive CRP and its relationship with the nutritional status of adolescents. Methods: Cross-sectional study conducted with overweight children and adolescents between August 2012 and July 2013 attended at the Center for Childhood Obesity. The measurement of inflammatory markers was performed in the Clinical Laboratory of the State University of Paraiba. Comparison of sociodemographic variables by sex was tested by chi-square;the association of the risk markers according to age was evaluated by Student’s t test, and the body mass index by analysis of Pearson correlation. The normality distribution was tested by the Kolmogorov-Smirnov test. Confidence interval of 95% was adopted in all analyses. The study was approved by the Ethics Research Committee of UEPB (CAAE 0256.***.133.000-11). Results: Of the 133 children and adolescents evaluated, 60.9% were female and 72.2% were adolescents. Body Mass Index, lipo (a) and u-CRP showed statistically significant association with age (p f u-CRP with BMI, which was not verified for lipoprotein (a). Conclusion: As a cardiovascular risk marker already established in literature, the association of u-CRP with the nutritional status of adolescents, proportionally, shows the need for losing weight in this population, especially at early age. A deeper and long-term investigation should be carried out for more effective and consistent contribution to public health.

关键词： Children Adolescents Obesity Lipoprotein C-Reactive Protein

Selection,effective dominance,and completeness of Cry1A.105/Cry2Ab2 dual-protein resistance in Helicoverpa zea(Boddie)(Lepidoptera:Noctuidae)

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Journal of Integrative Agriculture 2023年第7期22卷 2151-2161页

作者： Tiago silva Ying NIU Tyler TOWLES Sebe BROWN Graham PHEAD Wade WALKER fangneng HUANG department of Entomology Louisiana State University Agricultural CenterBaton RougeLouisiana 70817USA Macon Ridge Research Station Louisiana State University Agricultural CenterWinnsboroLouisiana 71295USA dean Research Station Louisiana State University Agricultural CenterAlexandriaLouisiana 71302USA Bayer Crop Science ChesterfieldMissouri 63017USA

In the U.S.,Helicoverpa zea(Boddie)is a major pest targeted by both transgenic maize and cotton expressing Bacillus thuringiensis(Bt)*** of insect to Bt maize and cotton containing cry1A and cry2A genes has widely occurred in the *** this study,two trials were performed to investigate larval survival and development of a Cry1A.105/Cry2Ab2 dual-protein resistant(VT2P-RR),a susceptible,and an f1 heterozygous(VT2P-RS)populations of *** on ears of nine Bt and three non-Bt maize *** Bt maize hybrids evaluated represent five common pyramided traits expressing two or three of the Cry1A.105,Cry1Ab,Cry1f,Cry2Ab2,and Vip3Aa20 *** the laboratory,neonates of the three *** populations were inoculated on silks of ears collected from maize at R1-R2 plant stages;and larval survivorship was checked 10 d after neonate *** three insect populations survived normally on non-Bt maize *** numbers of VT2P-RR and VT2P-RS survived on ears of Cry1A.105/Cry2Ab2 maize,while all larvae of the three populations died or could not develop on ears of Vip3Aa20-expressing *** results demonstrated that the dual-protein resistant *** was not cross-resistant to Vip3Aa20-expressing maize,and thus traits with vip3Aa20 gene should be effective to manage Cry1A.105/Cry2Ab2-resistant *** resistance in VT2P-RR was determined to be incomplete on Cry1A.105/Cry2Ab2 *** effective dominance levels varied greatly,from recessive to incompletely dominant,depending on maize hybrids and trials,suggesting that proper selection of maize hybrids could be important for mitigating the Cry1A.105/Cry2Ab2 *** data generated should aid in modeling multiple-protein Bt resistance in ***.

关键词： corn earworm Cry1A/Cry2A effective dominance incomplete resistance Bt maize resistance management

Upregulation of the APE1 and H2AX genes and miRNAs involved in DNA damage response and repair in gastric cancer

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Genes & Diseases 2019年第2期6卷 176-184页

作者： fernanda S.Manoel-Caetano Ana flávia T.Rossi Gabriela Calvet de Morais fábio Eduardo Severino Ana Elizabete silva department of Biology UNESPSāo Paulo State UniversityCampus of Sāo Josédo Rio PretoRua Cristòvāo Colombo226515.054-000Sāo Josédo Rio PretoSāo PauloBrazil department of Surgery and Orthopedics Faculty of MedicineUNESPSāo Paulo State UniversityCampus of BotucatuAv.Prof.Mário Rubens Guimarāes Montenegros/n18.618-687BotucatuSāo PauloBrazil

Gastric cancer remains one of the leading causes of cancer-related death worldwide,and most of the cases are associated with Helicobacter pylori *** bacterium promotes the production of reactive oxygen species(ROS),which cause DNA damage in gastric epithelial *** this study,we evaluated the expression of important genes involved in the recognition of DNA damage(ATM,ATR,and H2AX)and ROS-induced damage repair(APE1)and the expression of some miRNAs(miR-15a,miR-21,miR-24,miR-421 and miR-605)that target genes involved in the DNA damage response(DDR)in 31 fresh tissues of gastric *** v3.1.1 was used to construct the postulated miRNA:mRNA interaction *** performed by real-time quantitative PCR exhibited significantly increased levels of the APE1(RQ=2.55,pficantly elevated levels of miR-21,miR-24 and miR-421 were observed in diffuse-type gastric *** analysis reinforced some of the gene:gene(ATM/ATR/H2AX)and miRNA:mRNA relationships obtained also with the interaction ***,our findings show that tumor cells from gastric cancer presents deregulation of genes and miRNAs that participate in the recognition and repair of DNA damage,which could confer an advantage to cell survival and proliferation in the tumor microenvironment.

关键词： DNA damage response DNA repair Gastric cancer Gene expression microRNA

The Role of Nanodispersed Nitrides in the Sintering of Silicon Nitride Ceramics

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Plasma Science and Technology 2010年第1期12卷 46-48页

作者： M.GEORGIEVA G.VISSOKOV I.GRANCHAROV R.f.silva f.J.OLIVEIRA department of Technology of Inorganic Substances University of Chemical Technology and Metallurgy Institute of Catalysis Bulgarian Academy of Sciences Ceramics and Glass Eng. department CICECO University of Aveiro

The synthesis of ceramics based on silicon nitride using nanopowders of TiN and Si3N4 as additives was studied. The ceramic compositions were pressurelessly sintered under ni- trogen atmosphere at different temperatures （1550℃, 1650℃ and 1750℃） with a heating rate of 10℃/min and a holding time of 2 h. The nanodispersed nitrides （NDN） were produced by electric-arc plasma synthesis and characterized. The ceramic composites obtained with nanoparticles of 1wt% to 5wt% TiN and 20wt% Si3N4 were characterized by scanning electron microscopy （SEM）, atom force microscopy （AfM） and energy-dispersive spectrometry （EDX）. The effect of the addition of nanodispersed powders on the mechanical properties and microstructure of Si3N4 ceramics was investigated.

关键词： silicon nitride ceramics nanocomposites nanopowders