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Characterization and Modeling of Mechanical Properties of Additively Manufactured Coconut Fiber-Reinforced Polypropylene Composites

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Advances in Materials Physics and Chemistry 2024年第6期14卷 95-112页

作者： George Mosi Bernard w. Ikua Samuel K. Kabini James w. Mwangi Department of Mechatronic Engineering Jomo Kenyatta University of Agriculture and Technology Juja Kenya

In the face of the increased global campaign to minimize the emission of greenhouse gases and the need for sustainability in manufacturing, there is a great deal of research focusing on environmentally benign and renewable materials as a substitute for synthetic and petroleum-based products. Natural fiber-reinforced polymeric composites have recently been proposed as a viable alternative to synthetic materials. The current work investigates the suitability of coconut fiber-reinforced polypropylene as a structural material. The coconut fiber-reinforced polypropylene composites were developed. Samples of coconut fiber/polypropylene (PP) composites were prepared using Fused Filament Fabrication (FFF). Tests were then conducted on the mechanical properties of the composites for different proportions of coconut fibers. The results obtained indicate that the composites loaded with 2 wt% exhibited the highest tensile and flexural strength, while the ones loaded with 3 wt% had the highest compression strength. The ultimate tensile and flexural strength at 2 wt% were determined to be 34.13 MPa and 70.47 MPa respectively. The compression strength at 3 wt% was found to be 37.88 MPa. Compared to pure polypropylene, the addition of coconut fibers increased the tensile, flexural, and compression strength of the composite. In the study, an artificial neural network model was proposed to predict the mechanical properties of polymeric composites based on the proportion of fibers. The model was found to predict data with high accuracy.

关键词： Additive Manufacturing Artificial Neural Network Mechanical Properties Natural Fibers Polypropylene

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Association between baseline levels of muscular strength and risk of stroke in later life:The Cooper Center Longitudinal Study

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Journal of Sport and Health Science 2024年第5期13卷 642-649页

作者： Stephen w.Farrell David Leonard Qing Li Carolyn E.Barlow Kerem Shuval Jarett D.Berry Andjelka Pavlovic Laura F.DeFina Research Division The Cooper InstituteDallasTX 75230USA Department of Internal Medicine University of Texas at Tyler School of MedicineTylerTX 75799USA

Background:Muscular strength is an important component of physical *** evaluated the relationship between baseline muscular strength and risk of stroke among adults who were aged≥65 years during ***:we included 7627 healthy adults(mean age=43.9 years,86.0%male)underwent a baseline physical examination between 1980 and *** strength was determined by 1-repetition maximum measures for bench press and leg press and categorized into age-and sex-specific tertiles for each *** fitness(CRF)was assessed via a maximal treadmill exercise *** enrolled in fee-for-service Medicare from 1999 to 2019 were included in the *** between baseline strength and stroke outcomes were estimated using a modified Cox proportional hazards *** a secondary analysis,we examined stroke risk by categories of CRF where Quintile 1=low,Quintiles 2-3=moderate,and Quintiles 4-5=high CRF based on age and ***:After 70,072 person-years of Medicare follow-up,there were 1211 earliest indications of incident *** multivariable analyses,the hazard ratio(95%confidence interval(95%CI))for stroke across bench press categories were 1.0(referent),0.96(0.83-1.11),and 0.89(0.77-1.04),respectively(p trend=0.14).The trend across categories of leg press was also non-significant(p trend=0.79).Adjusted hazard ratio(95%CI)for stroke across ordered CRF categories were 1.0(referent),0.90(0.71-1.13),and 0.72(0.57-0.92)(p trendwhile meeting public health guidelines for muscular strengthening activities is likely to improve muscular strength as well as many health outcomes in older adults,performing such activities may not be helpful in preventing ***,meeting guidelines for aerobic activity is likely to improve CRF and lower stroke risk.

关键词： Cardiorespiratory fitness Medicare Muscular strength Stroke

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Surgeon preferences in the treatment of thumb carpometacarpal osteoarthritis

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world Journal of Orthopedics 2024年第5期15卷 435-443页

作者： Edward J wu Bradley w Fossum wyatt Vander Voort Christopher O Bayne Robert M Szabo Department of Orthopedic Surgery University of Minnesota Medical SchoolMinneapolisMN 55455United States Department of Orthopaedic Surgery UC Davis School of MedicineSacramentoCA 95817United States

BACKGROUND Primary thumb carpometacarpal(CMC)osteoarthritis is one of the most common conditions encountered by hand *** the vast number of operations that have been proposed,none have demonstrated results significantly superior to trapeziectomy *** The purpose of our study was to determine why surgeons opt for their technique in treating CMC *** A cross-sectional survey of active members of the American Society for Surgery of the Hand was conducted to evaluate the reasons behind their preferred technique in the treatment of isolated thumb CMC *** were contacted by email once and provided with a link to a de-identified survey consisting of 5 treatment questions and 5 demographic *** Of 950 responses were received.40.5%of surgeons preferred trapeziectomy+ligament reconstruction tendon interposition(LRTI),followed by trapeziectomy+suspensionplasty(28.2%),suture button suspension(5.9%),trapeziectomy alone(4.6%),prosthetic arthroplasty(3.2%),arthrodesis(1.1%),and other(6.6%).Proponents of trapeziectomy+LRTI cited familiarity(73.2%),exposure during fellowship(48.8%)and less proximal migration(60%)to be the main reasons affecting their *** who preferred trapeziectomy+suspensionplasty most reported simplicity(74.9%),fewer complications(45.3%),less proximal migration(43.8%),and avoidance of autogenous tissue harvest(42.7%).Advocates of suture button suspension cited avoidance of autogenous tissue harvest(80.4%),shorter immobilization(76.8%),and quicker recovery(73.2%)with their *** of trapeziectomy alone cited simplicity(97.7%),fewer complications(86.4%),and avoidance of autogenous tissue harvest(59.1%).In their comments,45%of surgeons choosing trapeziectomy alone cited evidence as an additional *** of prosthetic arthroplasty cited improved pinch strength(83.3%)and improved range of motion(63.3%),while those preferring arthrodesis cited better pinch strength(90%)and freque

关键词： Thumb carpometacarpal Osteoarthritis Trapeziectomy Ligament reconstruction tendon interposition Suspensionplasty Preferences Trends

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Barosinusitis due to routine weather changes:A cross-sectional analysis of public websites

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world Journal of Otorhinolaryngology-Head and Neck Surgery 2024年第1期10卷 18-23页

作者： James C.Campbell Julia E.Canick Philip G.Chen Ralph Abi Hachem David w.Jang Department of Head and Neck Surgery&Communication Sciences Duke University School of MedicineDurhamNorth CarolinaUSA Duke University School of Medicine DurhamNorth CarolinaUSA Department of Otolaryngology-Head and Neck Surgery University of Texas Health Science Center San AntonioSan AntonioTexasUSA

Background:Sinusitis is a common diagnosis that can be erroneously associated with routine weather‐related barometric pressure *** actuality,these pressure changes likely exacerbate migraine headaches,which can cause facial pain and pressure rather than true sinus ***:The present study sought to characterize the representation of both sinusitis and migraine in association with barometric pressure changes across websites on the ***:An Internet search for relevant terms was conducted,and content of the resulting pages was assessed for associations between weather‐related pressure changes and either sinusitis or *** in reported results across different subtypes of Internet sources were *** primary outcomes measured were(1)whether a given media source associated barometric weather changes with sinusitis,(2)whether that source associated barometric weather changes with migraine,and(3)treatment options offered by that ***:Of the 116 included webpages,36(31.03%)associated sinusitis and routine barometric pressure *** these,10(27.77%)were otolaryngology practice ***‐seven webpages(57.76%)associated migraine and routine barometric pressure *** these,nonotolaryngology webpages were more likely to report this ***:Otolaryngology practice sites were observed to be the most frequent professional medical resource reporting the unsubstantiated claim that routine barometric pressure changes are associated with *** sources were more likely to link weather‐related pressure changes to *** results suggest that opportunities exist for otolaryngology practice sites to educate patients about nonrhinogenic headache etiologies.

关键词： acute rhinosinusitis balloon sinus dilation headache migraine sinusitis

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Hydromechanical characterization of gas transport amidst uncertainty for underground nuclear explosion detection

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2019-2032页

作者： wenfeng Li Chelsea w.Neil J william Carey Meng Meng Luke P.Frash Philip H.Stauffer Earth and Environmental Sciences Los Alamos National LaboratoryLos AlamosNM87544USA Department of Mineral Engineering New Mexico TechSocorroNM87801USA

Given the challenge of definitively discriminating between chemical and nuclear explosions using seismic methods alone,surface detection of signature noble gas radioisotopes is considered a positive identification of underground nuclear explosions(UNEs).However,the migration of signature radionuclide gases between the nuclear cavity and surface is not well understood because complex processes are involved,including the generation of complex fracture networks,reactivation of natural fractures and faults,and thermo-hydro-mechanical-chemical(THMC)coupling of radionuclide gas transport in the *** this study,we provide an experimental investigation of hydro-mechanical(HM)coupling among gas flow,stress states,rock deformation,and rock damage using a unique multi-physics triaxial direct shear rock testing *** testing system also features redundant gas pressure and flow rate measurements,well suited for parameter uncertainty *** porous tuff and tight granite samples that are relevant to historic UNE tests,we measured the Biot effective stress coefficient,rock matrix gas permeability,and fracture gas permeability at a range of pore pressure and stress *** Biot effective stress coefficient varies from 0.69 to 1 for the tuff,whose porosity averages 35.3%±0.7%,while this coefficient varies from 0.51 to 0.78 for the tight granite(porositywing key engineering implications on transport of radionuclide gases post a UNE event:(1)The porous tuff shows apparent fracture dilation or compression upon stress changes,which does not necessarily change the gas permeability;(2)The granite fracture permeability shows strong stress sensitivity and is positively related to shear displacement;and(3)Hydromechanical coupling among stress states,rock damage,and gas flow appears to be

关键词： Underground nuclear explosion uncertainty quantification Radionuclide transport Biot effective stress coefficient Fracture permeability Matrix permeability

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COP 28: Challenge of coping with climate crisis

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The Innovation 2024年第1期5卷 21-22页

作者： Tong Jiang Xiaojia He Buda Su Peni Hausia Havea Ke wei Zbigniew w.Kundzewicz Dong Liu Research Institute of Climatic and Environmental Governance/Institute for Disaster Risk Management School of Geographical ScienceNanjing University of Information Science&TechnologyNanjing 210044China The Administrative Center for China’s Agenda 21 Beijing 100038China Pacific Global Solution Nuku’alofaTongatapu 000676Tonga Centre for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of Environmental Engineering and Mechanical Engineering Poznan University of Life Sciences60-637 PoznanPoland The Paper Shanghai United Media GroupShanghai 200040China

The 28th Conference of Parties(COP 28)of the United Nations Framework Convention on Climate Change(UNFCCC)is being held in Dubai,United Arab Emirates,from November 30 to December 12,2023,with the participation of over 160 world leaders(Figure 1).The tone of the COP 28 is set by the observation that,clearly,the nationally determined contributions related to CO_(2) emission reduction are not on track to curb the temperature rise as per the Paris *** order to hold the increase in global mean temperature to well below 2℃ above the pre-industrial level and to pursue efforts to limit the warming to 1.5℃,there is a need for ratcheting up ambition for near-term climate action.

关键词： Figure limit COP

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Current Zoology 2024年第1期70卷 1-12页

作者： Lucia V.Sommaro Juan J.Martinez Marina B.Chiappero Andrea R.Steinmann Cristina N.Gardenal Joséw.Priotto Laboratorio de Ecologia Evolutiva y Biogeografia Instituto de Ecorregiones Andinas(INECoA)Universidad Nacional de Jujuy-Consejo Nacional de Investigaciones Cientificas y Tecnicas(CONICET)San Salvador de JujuyJujuyArgentina Instituto de Diversidad y Ecologia Animal(IDEA) Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET)and Universidad Nacionalde CordobaCordobaArgentina Catedra de Genética de Poblaciones y Evolucion Facultad de Ciencias ExactasFisicas y NaturalesUniversidad Nacional de CordobaCordobaArgentina Grupo de Investigaciones en Ecologia Poblacional y Comportamental(GIEPCO) Instituto de Ciencias de la TierraBiodiversidad y Ambiente(ICBiA)Universidad Nacional de Rio Cuarto-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET)Rio CuartoCordobaArgentina

The sex-biased dispersal and kinship dynamics are important factors shaping the spatial distribution of individuals and are key parameters affecting a variety of ecological and evolutionary ***,we studied the spatial distribution of related individuals within a population of corn mice Calomys musculinus in a seasonal cycle to infer dispersal *** sampling was carried out from spring 2005 to winter 2006 in field borders of intensively managed *** data from 346 individuals with 9 microsatellites showed spatial genetic structure was weak for males,but not for *** results indicate a complex spatial kinship dynamic of related females across all ***,contrary to our expectations,dispersal distances decrease with the increase of the population ***,male dispersal distances were greater when population abundance increased and thus the availability of active *** disperse greater distances to mate and sire offspring with distant females as a possible inbreeding avoidance *** study shows that *** is capable of much greater scattering distances than previously reported and that dispersal occurs fluidly and without barriers across the *** indirect benefit of dispersal on individual fitness could be related to relaxing the competition in the natal area and increasing the mating *** study highlights the value of combining genetic relatedness,fieldwork observations,and behavioral data to estimate dispersal at a fine geographical scale.

关键词： dispersal distances kinship dynamics microsatellite small mammals spatial autocorrelation

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PNPLA8是调控三阴性乳腺癌磷脂代谢并促进肿瘤增殖和转移的关键分子（英文）

PNPLA8是调控三阴性乳腺癌磷脂代谢并促进肿瘤增殖和转移的关键分...

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2024中国肿瘤标志物学术大会暨CACA整合肿瘤学高峰论坛暨第十七届肿瘤标志物青年科学家论坛暨中国肿瘤标志物产业创新大会

作者：谭哲琼 Pragney Deme Keerti Boyapati Annet A.M.Duivenvoorden Ron M.A.Heeren Caitlin M.Tressler norman James Haughey Kristine Glunde

Background Triple-negative breast cancer(TNBC) is the most aggressive breast cancer subtype and leads to the poorest patient outcomes despite surgery and chemotherapy treatment. Exploring new molecular mechanisms of TNBC that could lead to the development of novel molecular targets are critically important for improving therapeutic options for treating *** we sought to identify novel therapeutic targets in TNBC by combining genomic and functional studies with lipidomic analysis, which included mechanistic studies to elucidate the pathways that tie lipid profile to critical cancer cell properties. Our studies were performed in a large panel of human breast cancer cell lines and patient *** Comprehensive lipid profiling revealed that phospholipid metabolism is reprogrammed in TNBC cells. we discovered that patatin-like phospholipase domain-containing lipase 8(PNPLA8)is overexpressed in TNBC cell lines and tissues from breast cancer patients. Silencing of PNPLA8disrupted phospholipid metabolic reprogramming in TNBC, particularly affecting the levels of phosphatidylglycerol(PG), phosphatidylcholine(PC), lysophosphatidylcholine(LPC) and glycerophosphocholine(GPC). we showed that PNPLA8 is essential in regulating cell viability,migration and antioxidation in TNBC cells and promoted arachidonic acid and eicosanoid production, which in turn activated PI3K/Akt/Gsk3β and MAPK *** Our study highlights PNPLA8 as key regulator of phospholipid metabolic reprogramming and malignant phenotypes in TNBC, which could be further developed as a novel molecular treatment target.

关键词： PNPLA8 Breast cancer Triple negative Phospholipid Metabolism reprogramming Eicosanoids Migration Invasion Proliferation

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Speciation:genomic sequence data and the biogeography of speciation

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National Science Review 2022年第12期9卷 13-14页

作者： norman A.Johnson Department of Biology University of Massachusetts–Amherst

Two papers in this issue show how the use of genomic sequence data can illuminate the biogeography of the speciation ***,I provide a backdrop to these studies,with a brief history of the use of markers and the biogeog... 详细信息

关键词： Speciation:genomic sequence data and the biogeography of speciation

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Stubborn Hypoxia in Neonates with D-Transposition of the Great Arteries after Arterial Switch Operation: Central Sleep Apnea as the Cause and Potential Indicator of Brain Immaturity

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Congenital Heart Disease 2024年第2期19卷 185-195页

作者： Camden L.Hebson Kyle Bliton Amr Y.Hammouda Kaitlyn Barr w.Hampton Gray Mohini Gunnett waldemar F.Carlo Department of Pediatrics Division of Pediatric CardiologyUniversity of Alabama BirminghamBirmingham35233USA Department of Pediatrics Division of Pediatric PulmonologyUniversity of Alabama BirminghamBirmingham35233USA Department of Pediatrics University of Alabama BirminghamBirmingham35233USA Department of Surgery Division of Cardiothoracic SurgeryUniversity of Alabama BirminghamBirmingham35233USA

D-transposition of the great arteries(d-TGA)is surgically repaired with the arterial switch operation(ASO)with excellent results,however short and long-term morbidities still develop including neurocognitive *** significant central sleep apnea is uncommon in non-premature infants,but when present indicates immature autonomic control of respiration likely due to a neurologic *** report the unanticipatedfinding of central sleep apnea in four-term neonates with d-TGA after uncomplicated ASO,with the short-term complication of delayed hospital discharge and long-term concerns regarding this early marker of brain immaturity and its hindrance to normal *** this report,we will review each patient’s clinical course and then examine the literature on pediatric central sleep apnea,neurodevelopmental outcomes after ASO,and the important overlap of these entities in the care of patients going forward.

关键词： Transposition congenital heart disease sleep apnea polysomnography

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