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Local hardening and asymmetric twin growth by twin-twin interactions in a Mg alloy

journal of Magnesium and Alloys 2023年第1期11卷 176-191页

作者： Krishna Yaddanapudi Mariyappan Arul Kumar jiaxiang Wang Xin Wang Timothy j.Rupert Enrique j.Lavernia julie M.Schoenung irene j.beyerlein Subhash Mahajan Department of Materials Science and Engineering University of CaliforniaDavisCA 95616USA Materials Science and Technology Division Los Alamos National LaboratoryLos AlamosNM 87545USA Department of Mechanical Engineering Materials DepartmentUniversity of CaliforniaSanta BarbaraCA 93106USA Department of Materials Science and Engineering University of CaliforniaIrvineUSA Materials Department University of CaliforniaSanta BarbaraCA 93106USA

In this study,the role of twin-twin interactions on the distributions of local defects(e.g.,dislocations)and stress fields in a magnesium alloy is investigated.A co-zone(1012)-(1012)tensile twin junction in a deformed Mg-3wt.%Y alloy is analyzed using transmission electron microscopy(TEM).The results show that the morphology of the impinging(1012)twin is asymmetric,and the non-interacting boundary of the recipient(1012)twin is irregular.Detailed analysis of TEM images reveals that type-II pyramidal[1213](1212)dislocations concentrate in the vicinity of the twin-twin junction site.The samedislocations are also observed inside the interacting twin domains along with a few dislocations.Thedislocations emanating from the impinging(1012)twin boundary have edge character and are extended with faults parallel to the basal plane.In contrast,thedislocations connected to the recipient(1012)twin are predominantly screw orientation and compact.Elasto-viscoplastic fast Fourier transform based crystal plasticity calculations are performed to rationalize the observed twin morphology and local dislocation distribution.The model calculations suggest that the local stress fields generated at the junction site where the two twins meet are responsible for the experimentally observed concentration ofdislocations.The calculated stress fields are asymmetric with respect to the junction site,explaining the observed asymmetric morphology of the impinging twin.Overall,these findings show strong effects of twin-twin interactions on the distribution of dislocations as well as the evolution of the twinned microstructure and as such,can help advance understanding of twinning in Mg alloys and their effect on mechanical behavior.

关键词： Tensile twins Twin-twin intersections Mg alloys Crystal plasticity TEM

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Interface-facilitated stable plasticity in ultra-fine layered FeAl/FeAl_(2) micro-pillar at high temperature

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journal of Materials Science & Technology 2021年第14期73卷 61-65页

作者： Lulu Li irene j.beyerlein Weizhong Han Center for Advancing Materials Performance from the Nanoscale State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi'an 710049China Department of Mechanical Engineering Materials DepartmentUniversity of CaliforniaSanta Barbara.CA.93106-5070USA

Fe-Al compounds possess a combination of high strength and corrosion resistance at high temperatures.However,increasing Al content to make them lighter results in embrittlement.Here,we investigate the high-temperature behavior of a novel,lightweight,ultra-fine-layered FeAl/FeAl_(2) material.We report a transition from unstable to stable plasticity at 450℃.Below 450℃,deformation is dominated by localized shear deformation within the soft FeAl layers,while above 450℃,it proceeds by co-deformation between Fe Al and the brittle FeAl_(2) layers.We show that co-deformation is associated with the temperature at which the interface converts from sliding to sourcing dislocations for Fe Al_(2).

关键词： Fe-Al alloy Compression High-temperature Interface Dislocation

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Multi-scale investigation of short-range order and dislocation glide in MoNbTi and TaNbTi multi-principal element alloys

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npj Computational Materials 2023年第1期9卷 1430-1442页

作者： Hui Zheng Lauren T.W.Fey Xiang-Guo Li Yong-jie Hu Liang Qi Chi Chen Shuozhi Xu irene j.beyerlein Shyue Ping Ong Department of NanoEngineering University of California San DiegoLa JollaCA 92093-0448USA Materials Department University of CaliforniaSanta BarbaraCA 93106-5050USA Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Materials Science and Engineering Drexel UniversityPhiladelphiaPA 19104USA Department of Mechanical Engineering University of CaliforniaSanta BarbaraCA 93106-5070USA

Refractory multi-principal element alloys(RMPEAs)are promising materials for high-temperature structural applications.Here,we investigate the role of short-range ordering(SRO)on dislocation glide in the MoNbTi and TaNbTi RMPEAs using a multi-scale modeling approach.Monte carlo/molecular dynamics simulations with a moment tensor potential show that MoNbTi exhibits a much greater degree of SRO than TaNbTi and the local composition has a direct effect on the unstable stacking fault energies(USFEs).From mesoscale phase-field dislocation dynamics simulations,we find that increasing SRO leads to higher mean USFEs and stress required for dislocation glide.The gliding dislocations experience significant hardening due to pinning and depinning caused by random compositional fluctuations,with higher SRO decreasing the degree of USFE dispersion and hence,amount of hardening.Finally,we show how the morphology of an expanding dislocation loop is affected by the applied stress.

关键词： alloys dislocation element

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Embryo-to-lamella transition of grain boundary twins in magnesium

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journal of Magnesium and Alloys 2023年第12期11卷 4485-4497页

作者： Mariyappan Arul Kumar irene j.beyerlein Materials Science and Technology Division Los Alamos National LaboratoryLos AlamosNM 87545USA Mechanical Engineering Department Materials DepartmentUniversity of CaliforniaSanta BarbaraCA 93106USA

A combined experimental and computational analysis is performed to investigate the less commonly studied embryo-to-lamella transition of deformation twins in magnesium. This work aims to understand the structural variables controlling the embryo-to-lamella transition from grain boundaries. Statistical analysis of hundreds of early-stage twins in the lightly deformed microstructure reveals a prevailing wedge shape,with a much thicker base along the grain boundary(GB) where they originate and a thinner tip terminating in the crystal. The analysis also shows that the GB base is super thick and identifies a minimum GB twin thickness among all early-stage twins that is about one micron. A crystal plasticity-based full-field model is employed to calculate the driving forces to migrate the boundary of a three-dimensional GB twin embryo. The stress analysis, considering a full range of embryo shapes and neighboring grain orientations, indicate that the twin embryo is most likely going to form a wedge shape when it first propagates. The calculations predict that the thickness of the embryo at the GB needs to be significantly larger than its length into the crystal in order to propagate into the crystal. The analysis finds that the more aligned the twin embryo variant is with basal slip in the neighboring grain, the thinner the twin embryo needed for propagation.

关键词： Magnesium Twin embryo Crystal plasticity Nucleation Grain neighbor

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Physical activity and amyloid beta in middle-aged and older adults:A systematic review and meta-analysis

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journal of Sport and Health Science 2024年第2期13卷 133-144页

作者： María Rodriguez-Ayllon Patricio Solis-Urra Cristina Arroyo-ávila Miriam álvarez-Ortega Pablo Molina-García Cristina Molina-Hidalgo Manuel Gómez-Río Belinda Brown Kirk I.Erickson irene Esteban-Cornejo Department of Epidemiology Erasmus University Medical Center RotterdamRotterdamGD 3015the Netherlands Department of Physical Education and Sports Faculty of Sport SciencesSport and Health University Research Institute(iMUDS)University of GranadaGranada 18071Spain Faculty of Education and Social Sciences Universidad Andres BelloVina del Mar 2531015Chile Department of Nuclear Medicine Virgen de las Nieves University HospitalInstitute of Biosanitary Research of Granada(IBS)Granada 18014Spain Physical Medicine and Rehabilitation Service Virgen de las Nieves University HospitalInstitute of Biosanitary Research of Granada(IBS)Granada 18014Spain Department of Psychology University of PittsburghPittsburghPA 15260USA Centre for Healthy Ageing Health Futures InstituteMurdoch UniversityMurdochWA 6150Australia School of Medical and Health Sciences Edith Cowan UniversityJoondalupWA 6027Australia Advent Health Research Institute Neuroscience Institute OrlandoOrlandoFL 32803USA Physiopathology of Obesity and Nutrition Research Center(CIBERobn) Institute of Health Carlos Ⅲ(ISCⅢ)Madrid 28029Spain

Background:One of the pathological hallmarks distinguishing Alzheimer’s disease from other dementias is the accumulation of amyloid beta(Aβ).Higher physical activity is associated with decreased dementia risk,and one potential path could be through Aβlevels modulation.We aimed to explore the relationship between physical activity and Aβin middle-aged and older adults.Methods:A systematic search of PubMed,Web of Science,PsycINFO,Cochrane Central Register of Controlled Trials,and SPORTDiscus was performed from inception to April 28,2022.Studies were eligible if they included physical activity and Aβdata in adults aged 45 years or older.Multi-level metaanalyses of intervention and observational studies were performed to examine the role of physical activity in modulating Aβlevels.Results:In total,37 articles were included(8 randomized controlled trials,3 non-randomized controlled trials,4 prospective longitudinal studies,and 22 cross-sectional studies).The overall effect size of physical activity interventions on changes in blood Aβwas medium(pooled standardized mean difference=-0.69,95%confidence interval(95%CI):-1.41 to 0.03;I^(2)=74.6%).However,these results were not statistically significant,and there were not enough studies to explore the effects of physical activity on cerebrospinal fluid(CSF)and brain Aβ.Data from observational studies were examined based on measurements of Aβin the brain using positron emission tomography scans,CSF,and blood.Higher physical activity was positively associated with Aβonly in the CSF(Estimate r=0.12;95%CI:0.05-0.18;I^(2)=38.00%).Conclusion:Physical activity might moderately reduce blood Aβin middle-aged and older adults.However,results were only near statistical significance and might be interpreted with caution given the methodological limitations observed in some of the included studies.In observational studies,higher levels of physical activity were positively associated with Aβonly in CSF.Therefore,further research is needed to understand the modulating role of physical act

关键词： Aging Cognitive impairment Dementia Exercise PET

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Late polymicrobial transjugular intrahepatic portosystemic shunt infection in a liver transplant patient:A case report

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World journal of Hepatology 2022年第4期14卷 846-853页

作者： irene De La Caridad Perez Ziv j Haskal john I Hogan Curtis K Argo Department of Medicine University of Virginia Medical CenterCharlottesvilleVA 22903United States Department of Radiology and Medical Imaging Division of Vascular and Interventional RadiologyUniversity of Virginia Medical CenterCharlottesvilleVA 22903United States Department of Medicine Division of Infectious Diseases and International HealthUniversity of Virginia Medical CenterCharlottesvilleVA 22903United States Department of Medicine Division of Gastroenterology and HepatologyUniversity of Virginia Medical CenterCharlottesvilleVA 22903United States

BACKGROUND Infection of a transjugular intrahepatic portosystemic shunt(TIPS)stent is a rare and serious complication that most commonly occurs during TIPS creation and revision.Patients typically present with recurrent bacteremia due to shunt occlusion or vegetation.To date there are approximately 58 cases reported.We present a patient diagnosed with late polymicrobial TIPS infection five years following TIPS creation.CASE SUMMARY A 63-year-old female status-post liver transplant with recurrent cirrhosis and portal hypertension presented with sepsis and recurrent extended-spectrum betalactamase Escherichia coli bacteremia.Computed tomography of the abdomen revealed an occluded TIPS with thrombus extension into the distal right portal vein,and focal thickening of the cecum and ascending colon.Colonoscopy revealed patchy ulcers in these areas with histopathology demonstrating ulcerated colonic mucosa with fibrinopurulent exudate.Shunt thrombectomy and revision revealed infected-appearing thrombus.Patient initially cleared her infection with antibacterial therapy and TIPS revision;however,soon after,she developed Enterobacter cloacae bacteremia and Candida glabrata and C.albicans fungemia with recurrent TIPS thrombosis.She remained on antifungal therapy indefinitely and later developed vancomycin-resistant Enterococcus faecium with recurrent TIPS thrombosis.The option of liver re-transplant for removal of the infected TIPS was not offered given her critical illness and complex shunt anatomy.The patient became intolerant to linezolid and elected hospice care.CONCLUSION Clinicians should be aware that TIPS superinfection may occur as long as five years following TIPS creation in an immunocompromised patient.

关键词： Transjugular intrahepatic portosystemic shunt Endotipsitis Colitis Liver cirrhosis Liver transplantation Case report

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Microarchitectural mimicking of stroma-induced vasculature compression in pancreatic tumors using a 3D engineered model

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Bioactive Materials 2023年第4期22卷 18-33页

作者： Marcel Alexander Heinrich irene Uboldi Praneeth Reddy Kuninty Marc j.K.Ankone joop van Baarlen Yu Shrike Zhang Kartik jain jai Prakash Department of Advanced Organ Bioengineering and Therapeutics Engineered Therapeutics SectionTechnical Medical CentreUniversity of Twente7500AEEnschedethe Netherlands Laboratorium Pathologie Oost-Nederland(LabPON) 7550 AMHengelothe Netherlands Division of Engineering in Medicine Department of MedicineBrigham and Women’s HospitalHarvard Medical School65 Landsdowne StCambridgeMA02139USA Department of Thermal and Fluid Engineering Biofluid Dynamics SectionUniversity of Twente7500 AE Enschedethe Netherlands

Fibrotic tumors,such as pancreatic ductal adenocarcinoma(PDAC),are characterized for high desmoplastic reaction,which results in high intra-tumoral solid stress leading to the compression of blood vessels.These microarchitectural alterations cause loss of blood flow and poor intra-tumoral delivery of therapeutics.Currently,there is a lack of relevant in vitro models capable of replicating these mechanical characteristics and to test anti-desmoplastic compounds.Here,a multi-layered vascularized 3D PDAC model consisting of primary human pancreatic stellate cells(PSCs)embedded in collagen/fibrinogen(Col/Fib),mimicking tumor tissue within adjunct healthy tissue,is presented to study the fibrosis-induced compression of vasculature in PDAC.It is demonstrated how the mechanical and biological stimulation induce PSC activation,extracellular matrix production and eventually vessel compression.The clinical relevance is confirmed by correlating with patient transcriptomic data.Furthermore,the effects of gradual vessel compression on the fluid dynamics occurring within the channel is evaluated in silico.Finally,it is demonstrated how cancer-associated fibroblast(CAF)-modulatory therapeutics can inhibit the cell-mediated compression of blood vessels in PDAC in vitro,in silico and in vivo.It is envisioned that this 3D model is used to improve the understanding of mechanical characteristics in tumors and for evaluating novel anti-desmoplastic therapeutics.

关键词： Pancreatic ductal adenocarcinoma Cancer-associated fibroblasts Collagen Fibrinogen Computational flow dynamics 3D in vitro model

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Immediate and long-term effects of invasive plant species on soil characteristics

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Soil Ecology Letters 2022年第3期4卷 276-288页

作者： irene M.Unger Robert j.Kremer Kristen S.Veum Keith W.Goyne Department of Biology and Chemistry Baker UniversityP.O.Box 65Baldwin CityKS 66006USA School of Natural Resources University of Missouri 302 ABNR Bldg.ColumbiaMO 65211USA USDA-ARS Cropping Systems and Water Quality UnitUniversity of Missouri302 ABNR Bldg.ColumbiaMO 65211USA Department of Forest Resources and Environmental Conservation Virginia Tech324 Cheatham HallBlacksburgVA 24061USA

Invasive plant species may alter soil characteristics or interact with the soil microbial community resulting in a competitive advantage.Our objectives were to determine:i)if invasive plant species alter soil properties;and ii)the long-term effects of invasive plant species on soil properties and subsequent implications on ecological restoration efforts.We focused on Lespedeza cuneata,a plant that may be allelopathic.Soil samples were collected from four locations in Central Missouri,USA:an old-field with abundant L.cuneata,two reconstructed sites,and a remnant prairie that has never been plowed.Soil health indictors were used to characterize soil properties at these sites.Nearly every soil property differed significantly between the unplowed prairie reference site and the other three sites.The reconstructed sites,however,generally did not differ from the invaded old-field.These results indicate that the reconstructed prairies are not fully recovered.Although above-ground traits,such as the plant community structure,appear similar to the prairie,the soil microbial community structure still resembles that of an invaded old-field site.These results indicate that more time may be needed before soil microbial populations fully recover after invasive plant removal.

关键词： Sericea lespedeza Legacy effects Soil microorganisms

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Association of accelerometer-derived step volume and intensity with hospitalizations and mortality in older adults:A prospective cohort study

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journal of Sport and Health Science 2022年第5期11卷 578-585页

作者： Asier Manas Borja del Pozo Cruz Ulf Ekelund joséLosa Reyna irene Rodríguez Gómez joséAntonio Carnicero Carreno Leocadio Rodríguez Manas Francisco j.García García Ignacio Ara GENUD Toledo Research Group University of Castilla-La ManchaToledo 45071Spain CIBER of Frailty and Healthy Aging(CIBERFES) Madrid 28029Spain Motivation and Behaviour Research Program Institute for Positive Psychology and EducationFaculty of Health SciencesAustralian Catholic UniversitySydneyNSW 2060Australia Department of Sports Medicine Norwegian School of Sport SciencesOslo 0806Norway Department of Chronic Diseases and Ageing Norwegian Institute of Public HealthOslo 0473Norway Geriatric Department Hospital Virgen del ValleToledo 45071Spain Geriatric Department Hospital Universitario de GetafeGetafe 28905Spain

Purpose:This study aimed to examine the associations of accelerometer-derived steps volume and intensity with hospitalizations and all-cause mortality in older adults.Methods:This prospective cohort study involved 768 community-dwelling Spanish older adults(78.8±4.9 years,mean±SD;53.9% females)from the Toledo Study for Healthy Aging(2012-2017).The number of steps per day and step cadence(steps/min) were derived from a hip-mounted accelerometer worn for at least 4 days at baseline.Participants were followed-up over a mean period of 3.1 years for hospitalization and 5.7 years for all-cause mortality.Cox proportional hazards regression models were used to estimate the individual and joint associations between daily steps and stepping intensity with hospitalizations and all-cause mortality.Results:Included participants walked 5835± 3445 steps/day with an intensity of 7.3± 4.1 steps/min.After adjusting for age,sex,body mass index(BMI),education,income,marital status and comorbidities,higher step count(hazard ratio(HR)=0.95,95% confidence interval(95%CI:0.90-1.00,and HR=0.87,95%CI:0.81-0.95 per additional 1000 steps) and higher step intensity(HR=0.95,95%CI:0.91-0.99,and HR=0.89,95%CI:0.84-0.95 per each additional step/min) were associated with fewer hospitalizations and all-cause mortality risk,respectively.Compared to the group having low step volume and intensity,individuals in the group having high step volume and intensity had a lower risk of hospitalization(HR=0.72,95%CI:0.52-0.98) and all-cause mortality(HR=0.60,95%CI:0.37-0.98).Conclusion:Among older adults,both high step volume and step intensity were significantly associated with lower hospitalization and all-cause mortality risk.Increasing step volume and intensity may benefit older people.

关键词： Aging Follow-up Objective Physical activity Walking

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Mediator complex subunit 12 is a gatekeeper of SARS-CoV-2 infection in breast cancer cells

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Genes & Diseases 2022年第1期9卷 5-8页

作者： Shengjie Zhang Fabao Liu Peter Halfmann Ryan TBehrens Peng Liu Sean jMcilwain irene MOng Kristine Donahue Yidan Wang Yoshihiro Kawaoka Nathan Sherer Wei Xua McArdle Laboratory for Cancer Research University of Wisconsin-MadisonMadisonWI 53706USA Department of Pathobiological Sciences School of Veterinary MedicineUniversity of WisconsinMadisonWI 53706USA Department of Biostatistics and Medical Informatics School of Medicine and Public HealthUniversity of WisconsinMadisonWI 53706USA Department of Biostatistics and Medical Informatics Carbone Cancer CenterUniversity of WisconsinMadisonWI 53706USA Department of Obstetrics and Gynecology School of Medicine and Public HealthUniversity of WisconsinMadisonWI 53706USA Cancer Hospital of the University of Chinese Academy of Sciences(Zhejiang Cancer Hospital) Institute of Basic Medicine and Cancer(IBMC)Chinese Academy of SciencesHangzhouZhejiang 310022China

Cancer patients are at increased risk for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection and mortality.Like other viruses in the SARS family,SARS-CoV-2 employs two host proteins,angiotensin-converting enzyme 2(ACE2)and transmembrane serine protease 2(TMPRSS2),for viral entry.1 Recent studies showed that many of the host proteins identified as potential targets for developing COVID therapies are dysregulated in cancer,2 prompting us to investigate whether human cancer cells are susceptible to SARS-CoV-2 infection,and whether chemotherapy could modulate a cancer patient's risk for infection.

关键词： infection ACE2 cancer

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