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Fast laser surface texturing of spherical samples to improve the frictional performance of elasto-hydrodynamic lubricated contacts

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Friction 2021年第5期9卷 1227-1241页

作者： g.BOIDI p.g.grützmacher A.KADIRIC F.J.pROFITO I.F.MACHADO C.gACHOT D.DINI Department of Mechanical Engineering Imperial College LondonSouth Kensington CampusLondon SW72AZUK AC2T research gmbH Wiener Neustadt 2700Austria polytechnic School University of São Paulo–USPSão Paulo 05508-030Brazil Department of Engineering Design and product Development TU WienWien 1060Austria Department of Material Science and Engineering Saarland UniversitySaarbrücken 66123Germany

Textured surfaces offer the potential to promote friction and wear reduction by increasing the hydrodynamic pressure,fluid uptake,or acting as oil or debris ***,texturing techniques often require additional manufacturing steps and costs,thus frequently being not economically feasible for real engineering *** experimental study aims at applying a fast laser texturing technique on curved surfaces for obtaining superior tribological performances.A femtosecond pulsed laser(Ti:Sapphire)and direct laser interference patterning(with a solid‐state Nd:YAg laser)were used for manufacturing dimple and groove patterns on curved steel surfaces(ball samples).Tribological tests were carried out under elasto‐hydrodynamic lubricated contact conditions varying slide‐roll ratio using a ball‐on‐disk ***,a specific interferometry technique for rough surfaces was used to measure the film thickness of smooth and textured *** steel samples were used to obtain data for the reference *** results showed that dimples promoted friction reduction(up to 20%)compared to the reference smooth specimens,whereas grooves generally caused less beneficial or detrimental *** addition,dimples promoted the formation of full film lubrication conditions at lower *** study demonstrates how fast texturing techniques could potentially be used for improving the tribological performance of bearings as well as other mechanical components utilised in several engineering applications.

关键词： surface laser texturing elasto‐hydrodynamic lubrication bearings friction film thickness

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Experimentally validated atomistic simulation of the effect of relevant grinding parameters on work piece topography,internal stresses,and microstructure

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Friction 2022年第4期10卷 608-629页

作者： S.J.EDER p.g.grützmacher T.SpENgER H.HECKES H.ROJACZ A.NEVOSAD F.HAAS AC2T research gmbH Viktor-Kaplan-Straße 2/CWiener Neustadt 2700Austria Institute of Engineering Design and product Development TU WienLehárgasse 6-Objekt 7Vienna 1060Austria Institute of production Engineering Graz University of TechnologyKopernikusgasse 24/IGraz 8010Austria Tyrolit-Schleifmittelwerke Swarovski K.g. Swarovskistraße 33Schwaz 6130Austria

In this work,we present a fully atomistic approach to modeling a finishing process with the goal to shed light on aspects of work piece development on the microscopic scale,which are difficult or even impossible to observe in experiments,but highly relevant for the resulting material *** a large-scale simulative parametric study,we varied four of the most relevant grinding parameters:The work piece material,the abrasive shape,the temperature,and the infeed *** order to validate our model,we compared the normalized surface roughness,the power spectral densities,the steady-state contact stresses,and the microstructure with proportionally scaled macroscopic experimental *** the grain sizes vary by a factor of more than 1,000 between experiment and simulation,the characteristic process parameters were reasonably reproduced,to some extent even allowing predictions of surface quality degradation due to tool *** the experimentally validated model,we studied time-resolved stress profiles within the ferrite/steel work piece as well as maps of the microstructural changes occurring in the near-surface *** found that blunt abrasives combined with elevated temperatures have the greatest and most complex impact on near-surface microstructure and stresses,as multiple processes are in mutual competition here.

关键词： large-scale molecular dynamics surface quality microstructure Revolutions per minute-Synchronous grinding(RpM-Synchronous grinding) tool wear

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Key factors to prioritize when preparing for the Olympic games

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Journal of Sport and Health Science 2024年第6期13卷 719-721页

作者： george p.Nassis gregoire p.Millet Department of physical Education College of EducationUnited Arab Emirates UniversityAl Ain 15551United Arab Emirates Institute of Sport Sciences University of LausanneLausanne 1015Switzerland

We need more research that will fulfill the needs of athletes and *** is a common statement,highly relevant nowadays only a few weeks before the commencement of the paris 2024 Olympic *** fill this gap,we have identified 6 topics that we feel coaches and athletes would be interested in learning more to optimize their preparation for the *** topics are.

关键词： preparing statement interested

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The great catastrophe: causes of the permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： paul B.Wignall David p.g.Bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(g evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern Boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

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Role of gut-liver axis and glucagon-like peptide-1 receptor agonists in the treatment of metabolic dysfunction-associated fatty liver disease

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World Journal of gastroenterology 2024年第23期30卷 2964-2980页

作者： Jakub Rochoń piotr Kalinowski Ksenia Szymanek-Majchrzak Michałgrąt Department of general Transplant and Liver SurgeryMedical University of WarsawWarsaw 02-097Poland Department of Medical Microbiology Medical University of WarsawWarsaw 02-004Poland

Metabolic dysfunction-associated fatty liver disease(MAFLD)is a hepatic manifestation of the metabolic *** is one of the most common liver diseases worldwide and shows increasing prevalence rates in most *** is a progressive disease with the most severe cases presenting as advanced fibrosis or cirrhosis with an increased risk of hepatocellular *** microbiota play a significant role in the pathogenesis and progression of MAFLD by disrupting the gut-liver *** mechanisms involved in maintaining gut-liver axis homeostasis are *** critical aspect involves preserving an appropriate intestinal barrier permeability and levels of intestinal lumen metabolites to ensure gutliver axis *** increase in intestinal barrier permeability induces metabolic endotoxemia that leads to ***,alterations in the absorption of various metabolites can affect liver metabolism and induce liver steatosis and ***-like peptide-1 receptor agonists(gLp-1 RAs)are a class of drugs developed for the treatment of type 2 diabetes *** are also commonly used to combat obesity and have been proven to be effective in reversing hepatic *** mechanisms reported to be involved in this effect include an improved regulation of glycemia,reduced lipid synthesis,β-oxidation of free fatty acids,and induction of autophagy in hepatic ***,multiple peptide receptor agonists have been introduced and are expected to increase the effectiveness of the treatment.A modulation of gut microbiota has also been observed with the use of these drugs that may contribute to the amelioration of *** review presents the current understanding of the role of the gutliver axis in the development of MAFLD and use of members of the gLp-1 RA family as pleiotropic agents in the treatment of MAFLD.

关键词： Metabolic dysfunction-associated fatty liver disease Metabolic dysfunction-associated steatohepatitis Nonalcoholic fatty liver disease Non-alcoholic steatohepatitis Metabolic syndrome Obesity gastrointestinal microbiota glucagon-like peptide-1 glucagon-like peptide-2 Bariatric surgery

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Magnesium oxide(MgO)nanoadsorbents in wastewater treatment:A comprehensive review

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Journal of Magnesium and Alloys 2024年第5期12卷 1709-1773页

作者： H.C.S.perera V.gurunanthanan Anoop Singh M.M.M.g.p.g.Mantilaka g.Das Sandeep Arya Department of physics Khalifa UniversityAbu Dhabi12788United Arab Emirates postgraduate Institute of Science University of PeradeniyaPeradeniyaSri Lanka Department of Humanities and Sciences Guru Nanak Institutions Technical CampusIbrahimpatnamHyderabad501506India Centre for global Health Research Saveetha Medical College and HospitalsSaveetha Institute of Medical and Technical SciencesChennai602105Tamil NaduIndia Department of physics University of JammuJammu and Kashmir180006India

Wastewater contamination by heavy metals and synthetic dyes presents a significant environmental challenge,necessitating effective and sustainable separation *** review article provides a detailed examination of magnesium oxide(MgO)nanoparticles as an innovative nanoadsorbent for wastewater treatment,with a specific focus on heavy metal and dye *** review comprehensively explores various aspects of MgO nanoparticles,including their structural characteristics and synthesis *** article delves into the morphology and crystallographic arrangement of MgO nanoparticles,offering insights into their structural *** the complexity of adsorption processes,the review identifies and analyzes parameters influencing the adsorption efficiency of MgO nanoparticles,such as temperature,pH,contact time,initial concentration,and co-existing *** interplay between these parameters and the adsorption capability of MgO nanoparticles emphasizes the importance of optimizing operational ***,the review assesses various synthesis methods for MgO nanoparticles,including sol-gel,hydrothermal,precipitation,green synthesis,solvothermal,and template-assisted *** discusses the advantages,limitations,and resulting nanoparticle characteristics of each method,enabling readers to grasp the implications of synthesis processes on adsorption *** comprehensive review consolidates current insights into the effectiveness of MgO nanoparticles as a potent nanoadsorbent for removing heavy metals and dyes from wastewater covering a wide spectrum of aspects related to MgO ***,there is a need to investigate the use of MgO in the treatment of actual wastewater or river water,in order to leverage its cost-effectiveness and high efficiency for practical water treatment applications in real-time.

关键词： MgO nanoparticles Nanoadsorbent Wastewater treatment Heavy metals Dye separation Adsorption Synthesis methods

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Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

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Chinese physics B 2024年第2期33卷 108-114页

作者： U.S.Mahabaleshwar g.p.Vanitha L.M.pérez Emad H.Aly I.pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked *** the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching ***,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O ***,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow analytical solution suction/injection

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Immune consequences of exercise in hypoxia:A narrative review

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Journal of Sport and Health Science 2024年第3期13卷 297-310,I0002页

作者： Johannes Burtscher Qadar pasha Neha Chanana gregoire p.Millet Martin Burtscher Barbara Strasser Institute of Sport Sciences University of LausanneLausanne 1015Switzerland Institute of Hypoxia Research New Delhi 110067India Department of Biochemistry Jamia HamdardNew Delhi 110062India Department of Sport Science University of InnsbruckInnsbruck 6020Austria Faculty of Medicine Sigmund Freud Private UniversityVienna 1020Austria Ludwig Boltzmann Institute for Rehabilitation Research Vienna 1100Austria

Immune outcomes are key mediators of many health benefits of exercise and are determined by exercise type,dose(frequency/duration,intensity),and individual ***,reduced availability of ambient oxygen(hypoxia)modulates immune functions depending on the hypoxic dose and the individual capacity to respond to *** combined exercise and hypoxia(e.g.,high-altitude training)sculpts immune responses is not well understood,although such combinations are becoming increasingly ***,in this paper,we summarize the impact on immune responses of exercise and of hypoxia,both independently and together,with a focus on specialized cells in the innate and adaptive immune *** review the regulation of the immune system by tissue oxygen levels and the overlapping and distinct immune responses related to exercise and hypoxia,then we discuss how they may be modulated by nutritional ***,antioxidant,and anti-inflammatory mechanisms underlie many of the adaptations that can lead to improved cellular metabolism,resilience,and overall immune functions by regulating the survival,differentiation,activation,and migration of immune *** review shows that exercise and hypoxia can impair or complement/synergize with each other while regulating immune system *** acclimatization,training,and nutritional strategies can be used to avoid risks and tap into the synergistic potentials of the poorly studied immune consequences of exercising in a hypoxic state.

关键词： Altitude Exercise Hypoxia Immune response Training

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paper Analytical Device for the Colourimetric Detection of Alkaline phosphatase in Serum and Saliva

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Journal of Analysis and Testing 2024年第03期8卷 385-394页

作者： D.Alageswari A.LakshmiDevi p.E.Resmi p.V.Suneesh Aarathipradeep T.g.SatheeshBabu Department of Chemistry Amrita School of Physical Sciences Coimbatore Amrita Vishwa Vidyapeetham Amrita Biosensor Research Lab Amrita School of Engineering Coimbatore Amrita Vishwa Vidyapeetham Amrita Biomedical Engineering Centre Amrita School of Engineering Coimbatore Amrita Vishwa Vidyapeetham

A paper analytical device (pAD) was developed for the colourimetric estimation of alkaline phosphatase (ALp). ALp catalyzes the hydrolysis of disodium phenyl phosphate (DSpp) to phenol, which then undergoes oxidative coupling with4-aminoantipyrine (4-AAp) producing a reddish brown-coloured quinone imine. The colourimetric reaction tested in solution has been translated onto a pAD for the point of care (poC) testing of ALp. A uniform colour was obtained in 25 min with the introduction of ALp onto the reagent drop cast paper device. The images obtained by scanning the pAD were processed using ImageJ software. The colour intensity obtained by image processing was proportional to the concentration of ALp present in the sample. ALp in serum and saliva samples were tested using the pAD in the range of 0 to 528 U/L and0 to 187 U/L, respectively. The interference studies revealed that the pAD was selective to ALp in the presence of other biomolecules. The pAD exhibited a limit of detection (LOD) of 3.3 U/L and a sensitivity of 48.36 a.u/Log(U/L) for serum ALp and LOD of 1.69 U/L and a sensitivity of 28.5 a.u/Log (U/L) for salivary ALp. The pAD showed good agreement with the clinical methods for real samples.

关键词： Alkaline phosphatase Colourimetry ImageJ paper analytical device point of care testing

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Understanding Behavioral Manifestations of Obsessive-Compulsive Disorder in people with Intellectual Disabilities—A Qualitative Study

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Open Journal of psychiatry 2024年第2期14卷 67-90页

作者： Lena grüter Matthias grünke Department of Rehabilitation and Special Education University of Cologne Cologne Germany

Background: There is limited knowledge about obsessive-compulsive disorder (OCD) in people with intellectual disabilities (IDs). This paper describes the manifestation of compulsive behaviors associated with OCD at the behavioral level in people with ID in institutionalized settings. The aim was to gain nuanced insight into appropriate understanding and classification in this specific context, and derive implications for research and practice. Methods: Individual cases of people with ID (n = 7) were studied to assess compulsive symptoms through two days of on-site observation of the person with ID within the institution, guided group discussions (n = 28), and semi-structured interviews with key informants and caregivers of the person with ID (n = 20). Caregiver ratings of the compulsive behavior checklist were compiled. Data were analyzed using qualitative content analysis. Results: All forms of OCD were present. Characteristics of compulsive behaviors in people with ID at the behavioral level included less complex and more obvious compulsive acts, immediate responses, signs of tension, motor restlessness, facial expression changes, repetition, need for predictability, time-consuming behaviors, and aggressive reactions when these acts were interrupted. Some of the compulsive behaviors corresponded to the ICD-11 OCD code 6B20, and others to compulsions as a psychological symptom (MB23.4). Conclusions: OCD may manifest atypically at the behavioral level in people with ID, posing significant challenges for accurate classification due to symptom ambiguity. Follow-up differential diagnostic studies are needed to more accurately identify and differentiate OCD symptoms in people with ID. Further, disorder-specific guidelines for recognizing OCD in people with ID are needed for institutionalized settings without psychiatric-psychotherapeutic expertise.

关键词： people with Intellectual Disabilities Obsessive-Compulsive Disorder Compulsive Behavior Diagnostics Differential Diagnosis

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