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Numerical simulation of three dimensional concrete printing based on a unified fluid and solid mechanics formulation

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 491-515页

作者： Janis REINOLD Koussay DAADOUCH günther MESCHKE Institute for Structural Mechanics Ruhr University BochumBochum 44801Germany

Deformation control constitutes one of the main technological challenges in three dimensional(3D)concrete printing,and it presents a challenge that must be addressed to achieve a precise and reliable construction ***-based information of the expected deformations and stresses is required to optimize the construction process in association with the specific properties of the concrete *** this work,a novel thermodynamically consistent finite strain constitutive model for fresh and early-age 3D-printable concrete is *** model is then used to simulate the 3D concrete printing process to assess layer shapes,deformations,forces acting on substrate layers and prognoses of possible structural collapse during the layer-by-layer *** constitutive formulation is based on a multiplicative split of the deformation gradient into elastic,aging and viscoplastic parts,in combination with a hyperelastic potential and considering evolving material properties to account for structural buildup or *** advantage of this model is the stress-update-scheme,which is similar to that of small strain plasticity and therefore enables an efficient integration with existing material *** constitutive model uses the particle finite element method,which serves as the simulation framework,allowing for modeling of the evolving free surfaces during the extrusion *** analyses of three printed layers are used to create deformation plots,which can then be used to control the deformations during 3D concrete *** study offers further investigations,on the structural level,focusing on the potential structural collapse of a 3D printed concrete *** capability of the proposed model to simulate 3D concrete printing processes across the scales—from a few printed layers to the scale of the whole printed structure—in a unified fashion with one constitutive formulation,is demonstrated.

关键词： particle finite element method 3D concrete printing multiplicative split additive manufacturing elastoviscoplasticity

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Unveiling the early universe:Axion-like particles and their role in primordial structure formation

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 178-179页

作者： Sergey g.Rubin National Research Nuclear University MEPhI(Moscow Engineering Physics Institute) Moscow 115409Russia

The groundbreaking discovery of gravitational waves(gWs)by the LIgO-VIRgO-KAgRO collaboration has revolutionized our understanding of the universe and opened up a new way of observing cosmic events. Unlike light waves... 详细信息

关键词： universe gravitational cosmic

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Summary of a Life in Observational Ultraviolet/Optical Astronomy

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Research in Astronomy and Astrophysics 2024年第1期24卷 1-43页

作者： Donald g.York Department of Astronomy and Astrophysics The University of Chicago5801 South Ellis Ave.Chicago 60637ILUSA

I reminisce on my early life in Section 1;on my education in Sections 2 and 3;on the years at Princeton as a research astronomer in Section 4;on the years on the faculty at Chicago in Section 5;on research on Diffuse Interstellar Bands(DIBs) in Section 6;on construction of the 3.5 m telescope at Apache Point Observatory(APO)in Section 7;on work on the Sloan Digital Sky Survey(SDSS) in Section 8;on work in public education in Chicago in Section 9;and on my travels in Section 10. My main science research is of an observational nature,concerning galactic and intergalactic interstellar gas. Highlights for me included my work on the orbiting telescope Copernicus, including the discovery of interstellar deuterium;early observations of absorption associated with fivetimes ionized oxygen;and discoveries concerning the phases of gas in the local interstellar medium, based on previously unobservable interstellar UV spectral lines. With other instruments and collaborations, I extended interstellar UV studies to the intergalactic cool gas using quasi-stellar object QSO absorption lines redshifted to the optical part of the spectrum;provided a better definition of the emission and morphological character of the source of absorption lines in QSO spectra;and pursued the identification of the unidentified DIBs. For several of these topics, extensive collaborations with many scientists were essential over many years. The conclusions developed slowly, as I moved from being a graduate student at Chicago, to a research scientist position at Princeton and then to a faculty position at Chicago. At each stage of life, I was exposed to new technologies adaptable to my science and to subsequent projects. From high school days, I encountered several management opportunities which were formative. I have been extremely fortunate both in scientific mentors I had and in experimental opportunities I encountered.

关键词： Interstellar Medium(ISM) Nebulae (galaxies:)quasars:absorption lines ultraviolet:stars

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From the dust:extracellular vesicles as regulators of development and neuroregeneration

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Neural Regeneration Research 2024年第5期19卷 933-934页

作者： Leon g.Coleman Jr The University of North Carolina at Chapel Hill School of MedicineDepartment of PharmacologyBowles Center for Alcohol StudiesChapel HillNCUSA

First impressions can have a lasting *** science,this can be especially problematic,because our lack of understanding often causes us to mislabel and thus ignore important biological *** this vein,extracellular vesicles(EVs)were once considered to be“cellular dust”.Similar to the previous concept of“junk DNA”to describe protein non-coding regions,EVs are far more than just cellular *** fact,EVs are emerging as key mediators of intracellular communication across nearly all biological *** includes peripheral immune responses(e.g.,arthropathies and sepsis),intra-organ communication(Seim et al.,2023),and a host of other physiological and pathological states(Figure 1A and B).

关键词： Figure extracellular

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Loggerhead Sea Turtles Hand-Reared in Captivity: Isotopic Insights into Their Inherent Dietary Variation

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Open Journal of Ecology 2024年第5期14卷 435-454页

作者： Brenda Natasha Mejía-guarnizo Carlos Julio Polo-Silva guiomar Aminta Jauregui-Romero Antonio delgado-Huertas Centro de Investigaciones en Ciencias Marinas (CICIMAR-IPN) La Paz M&#233xico Marine Biology Program Faculty of Natural Sciences and Engineering Jorge Tadeo Lozano University Santa Marta Colombia Sharky Management and Consulting Oldsmar FL USA Programa de Conservació n de Tortugas y Mam&#237feros Marinos (ProCTMM) Santa Marta Colombia Instituto Andaluz de Ciencias de la Tierra (CSIC-UgR) Armilla Spain

Stable isotope analysis is a widely used method for gathering ecological insights into the diet and feeding habitats of various species. While captive studies often limit lethal sampling and differ from wild conditions, they offer valuable insights into inherent isotopic variations among individuals, which are often assumed to reflect differences between natural populations. In the Sea Turtle Conservation Program, loggerhead turtle hatchlings from different nests were fed. Necropsies were conducted on turtles that died during this period, obtaining bone fragments for analysis. We evaluated the isotopic variation of carbon (δ13C) and nitrogen (δ15N) in bone tissue across six turtle nests (n = 66 samples) and assessed differences in Straight Carapace Length (SCL, n = 71 samples). Using SIBER and nicheROVER in R, we calculated niche width and overlap, while the simmr package determined primary prey assimilation. Despite feeding the hatchlings the same prey, we observed variations in nitrogen isotope assimilation between nests. Nests 4 and 6 had a niche width >1.8‰, indicating consistent consumption frequencies across all prey and >70% niche overlap with other nests. In contrast, nests 1 and 2 showed a narrower niche width (Mugil sp. constituted the primary diet component (>40%) across all groups. This study demonstrates how factors like competition or prey preference can influence the assimilation of diet, even when the source remains constant (inherent variation).

关键词： Stable Isotopes Caretta caretta Head-Starting Nests Straight Carapace Length

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Endotoxin-induced alterations of adipose tissue function:a pathway to bovine metabolic stress

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Journal of Animal Science and Biotechnology 2024年第4期15卷 1391-1407页

作者： Miguel Chirivi g.Andres Contreras Department of Large Animal Clinical Sciences Michigan State UniversityEast LansingMIUSA

During the periparturient period, dairy cows exhibit negative energy balance due to limited appetite and increased energy requirements for lactogenesis. The delicate equilibrium between energy availability and expenditure puts cows in a state of metabolic stress characterized by excessive lipolysis in white adipose tissues(AT), increased production of reactive oxygen species, and immune cell dysfunction. Metabolic stress, especially in AT, increases the risk for metabolic and inflammatory diseases. Around parturition, cows are also susceptible to endotoxemia. Bacterial-derived toxins cause endotoxemia by promoting inflammatory processes and immune cell infiltration in different organs and systems while impacting metabolic function by altering lipolysis, mitochondrial activity, and insulin sensitivity. In dairy cows, endotoxins enter the bloodstream after overcoming the defense mechanisms of the epithelial barriers, particularly during common periparturient conditions such as mastitis, metritis, and pneumonia, or after abrupt changes in the gut microbiome. In the bovine AT, endotoxins induce a pro-inflammatory response and stimulate lipolysis in AT, leading to the release of free fatty acids into the bloodstream. When excessive and protracted, endotoxin-induced lipolysis can impair adipocyte's insulin signaling pathways and lipid synthesis. Endotoxin exposure can also induce oxidative stress in AT through the production of reactive oxygen species by inflammatory cells and other cellular components. This review provides insights into endotoxins' impact on AT function, highlighting the gaps in our knowledge of the mechanisms underlying AT dysfunction, its connection with periparturient cows' disease risk, and the need to develop effective interventions to prevent and treat endotoxemia-related inflammatory conditions in dairy cattle.

关键词： Adipose tissue dysfunction Endotoxin Inflammation Insulin resistance

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Interpreting siliciclastic sedimentation in the upper Paleozoic Mulargia-Escalaplano Basin(Sardinia, Italy):influence of tectonics on provenance

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Journal of Palaeogeography 2024年第1期13卷 18-34页

作者： Luca g.Costamagna Sara Criniti Dipartimento di Scienze Chimiche e geologiche Citadella UniversitariaBlocco A09042 Monserrato CAItaly Dipartimento di Ingegneria dell'Ambiente Universita della Calabria87036 Arcavacata di Rende CSItaly

Late to post-Variscan molassic basins of Late Pennsylvanian-Permian age are exposed in Sardinia(Italy). Here, the compositional and stratigraphic evolution of the Mulargia-Escalaplano sedimentary basin(central Sardinia) has been investigated to highlight how the tectono-magmatic processes have influenced the sedimentation. Ruditic and arenitic samples were collected along well-characterized stratigraphic sections to provide a new insight into the impact of the tectono-magmatic processes on siliciclastic sedimentation. As a result, the conglomerates are mainly clast-supported, petromictic, and thus immature, with no defined maturity trend upwards. Nevertheless, pebble composition changes in times from Variscan basement pebble-rich to volcanic rock-rich, as a consequence of the basin widening and the dismantling and reworking of the coeval volcanic activity. The sandstone composition clearly changes from quartzolithic to feldspatholithic upwards, as a response to the same change of feeding and reworking of the volcanic rocks. Occasionally, interbedded quartzolithic arenites suggest exceptional floods carrying debris from the far borders of the basin. Also, the immature sandstone composition has been interpreted as being controlled by a continuous supply of fresh debris and to a rapid burial rate. In addition, the disappearance of metaradiolarite(lydite AA) Paleozoic grains in the sandstone mineral suite could represent a distinctive marker of a progressive unroofing of the Variscan chain and a clastic supply from deeper tectonic units.

关键词： Petrography Stratigraphy Provenance Molassic basins Sardinia

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Incidence of urinary incontinence following endoscopic laser enucleation of the prostate by en-bloc and non-en-bloc techniques:a multicenter,real-world experience of 5068 patients

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Asian Journal of Andrology 2024年第3期26卷 233-238页

作者： Daniele Castellani Vineet gauhar Khi Yung Fong Mario Sofer Moisés Rodríguez Socarrás Azimdjon N Tursunkulov Lie Kwok Ying Sarvajit Biligere Ho Yee Tiong Dean Elterman Abhay Mahajan Mark Taratkin Sorokin Nikolai Ivanovich Tanuj Pal Bhatia Dmitry Enikeev Nariman gadzhiev Mohammed Taif Bendigeri Jeremy Yuen-Chun Teoh Marco Dellabella Fernando gómez Sancha Bhaskar Kumar Somani Thomas Reinhard William Herrmann Urology Unit IRCCS INRCAAncona 60127Italy Urology Unit Marche University HospitalLe Marche Polytechnic UniversityAncona 60126Italy Department of Urology Ng Teng Fong General HospitalSingapore 609606Singapore Yong Loo Lin School of Medicine National University of SingaporeSingapore 117597Singapore Department of Urology Tel Aviv Sourasky Medical CenterAffiliated to the Sackler School of MedicineTel Aviv UniversityTel Aviv 6423906Israel Department of Urology and Robotic Surgery ICUA-Clínica CEMTROMadrid 28701Spain Urology Division Akfa Medline HospitalTashkent 100211Uzbekistan Advanced Urology Gleneagles HospitalSingapore 258499Singapore Department of Urology National University HospitalSingapore 119228Singapore Divisionof Urology Department of SurgeryUniversity of TorontoOntarioToronto M5G 2C4Canada Department of Urology Mahatma Gandhi Mission’s Medical College and HospitalAurangabad 431003India Institute for Urology and Reproductive Health Sechenov UniversityMoscow119435Russian Federation Department of Urologyand Andrology Lomonosov Moscow State UniversityMoscow 119992Russian Federation Department of Urology Sarvodaya Hospital and Research CentreFaridabadHaryana 121006India Department of Urology Medical University of ViennaVienna 1090Austria Department of Urology Saint-Petersburg State University HospitalSaint-Petersburg 199034Russian Federation Department of Urology Asian Institute of Nephrology and UrologyHyderabad 500082India S.H.Ho UrologyCentre Department of SurgeryFaculty of MedicineThe Chinese University of Hong KongHong Kong 96H2+Q9China Department of Urology University Hospitals Southampton NHS TrustSouthampton SO166YDUnited Kingdom Department of Urology Cantonal Hospital Thurgau AGFraunfeld 8500Switzerland

We aim to evaluate the incidence of incontinence following laser endoscopic enucleation of the prostate(EEP)comparing en-bloc(group 1)versus 2-lobe/3-lobe techniques(group 2).We performed a retrospective review of patients undergoing EEP for benign prostaticenlargement in 12 centers between January 2020 and January *** were presented as median and interquartile range(IQR).Univariable and multivariable logistic regression analysis was performed to evaluate factors associated with stress urinary incontinence(SUI)and mixed urinary incontinence(MUI).There were 1711 patients in group 1 and 3357 patients in group *** in group 2were significantly younger(68[62–73]years vs 69[63–74]years,P=0.002).Median(interquartile range)prostate volume(PV)wassimilar between the groups(70[52–92]ml in group 1 vs 70[54–90]ml in group 2,P=0.774).There was no difference in preoperativeInternational Prostate Symptom Score,quality of life,or maximum flow ***,morcellation,and total surgical time weresignificantly shorter in group *** 1 month,overall incontinence rate was 6.3%in group 1 versus 5.3%in group 2(P=0.12),and urge incontinence was significantly higher in group 1(55.1%vs 37.3%in group 2,Pgroup 1 versus 2.3%in group 2(P=0.06),and SUI was significantly higher in group 2(55.6%vs 24.1%in group 1,P=0.002).At multivariable analysis,PV and IPSS were factors significantly associated with higher odds of transient SUI/***,surgical time,and no early apical release technique were factors associated with higher odds of persistent SUI/MUI.

关键词： benign prostatic hyperplasia en-bloc enucleation endoscopic enucleation of the prostate laser therapy stress urinaryincontinence urge urinary incontinence

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Dinophysoid dinoflagellates from subphotic depths:Amphisolenia ***,Dinofurcula tricornuta ***.,and Dinophysis profunda ***.(Dinophysales,Dinophyceae)

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Journal of Oceanology and Limnology 2022年第2期40卷 703-711页

作者： Fernando gÓmez Department of Biological and Environmental Sciences and Technologies University of SalentoLecce 73100Italy

Three species of dinophysoid planktonic dinoflagellates are described from the eastern Mediterranean *** *** was collected at 70-m depth in the Ionian *** small species showed a more asymmetric midbody and a proportionally longer neck when compared to the closer relative *** individuals of Dinofurcula tricornuta *** at 154-m depth in the Marmara Sea are characterized by three posterior-oriented processes when compared to its congeneric *** is the first record of the genus Dinofurcula beyond the eastern tropical Pacific *** profunda *** at 500-m depth in the Ionian Sea is characterized by ovate hypotheca and a serrate crest-like left sulcal list when compared to its close relative *** findings evidence an undescribed biodiversity in the under-sampled subphotic depths.

关键词： deep ocean Dinophyta Dinoflagellata Mediterranean Sea mesopelagic new species

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First-principles calculation on the electronic structures, phonon dynamics, and electrical conductivities of Pb_(10)(PO_(4))_(6O) and Pb_(9)Cu(PO_(4))_(6O) compounds

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Journal of Materials Science & Technology 2024年第6期173卷 218-224页

作者： L.Y.Hao E.g.Fu State Key Laboratory of Nuclear Physics and Technology Department of Technical PhysicsSchool of PhysicsPeking UniversityBeijing 100871China

Superconducting materials with high critical temperature have the potential to revolutionize many fields,including military,electronic communications,and power ***,scientists around the world have been tirelessly working with the ultimate goal of achieving high-temperature *** 2023,a preprint by Lee et *** South Korea claimed the discovery of ultra-high-temperature superconductivity with a critical temperature of up to 423 K in Cu-doped lead-apatite(LK-99)(arXiv:2307.12008,arXiv:2307.12037),which caused a worldwide sensation and ***,the electronic structures,phonon dynamics,and electrical conductivities of LK-99 and its parent compound lead-apatite have been calculated using first-principles *** results show that the lead-apatite compound and the LK-99 compound are insulator and half-metal *** flat band characteristic is consistent with previous *** electrical conductivity of the LK-99 compound shows two extreme points,and the electrical conductivity along the C-axis increases significantly after 400 *** phonon dispersion spectra of the compounds were investigated,demonstrating their dynamic instability.

关键词： Superconductivity LK-99 Lead-apatite First-principles calculation

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