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Finite element analysis and experimental validation of polymer-metal contacts in block-on-ring configuration

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Friction 2024年第3期12卷 554-568页

作者： K.Y.Eayal AWWAD Khosro FALLAHNEZHAD b.F.YOUSIF Ahmad MOSTAFA omar ALAJARMEH A.SHALWAN Xuesen ZENG Mechanical Engineering Department Faculty of EngineeringTafila Technical UniversityTafila 66110Jordan Medical Device Research Institute College of Science and EngineeringFlinders UniversitySouth Australia 5042Australia Centre for Future Materials University of Southern QueenslandToowoomba 4350Australia Department of Manufacturing Engineering Technology Public Authority for Applied Education and TrainingKuwait 13092Kuwait

The wear profile analysis,obtained by different tribometers,is essential to characterise the wear ***,most of the available methods did not take the stress distribution over the wear profile in consideration,which causes inaccurate *** this study,the wear profile of polymer–metal contact,obtained by block-on-ring configuration under dry sliding conditions,was analysed using finite element modelling(FEM)and experimental ***’s wear equation was integrated into a developed FORTRAN-UMESHMOTION code linked with Abaqus software.A varying wear coefficient(k)values covering both running-in and steady state regions,and a range of applied loads involving both mild and severe wear regions were measured and implemented in the *** FEM was in good agreement with the *** model reproduced the stress distribution profiles under variable testing conditions,while their values were affected by the sliding direction and maximum wear depth(hmax).The largest area of the wear profile,exposed to the average contact stresses,is defined as the normal *** the critical zones were characterized by high stress concentrations reaching up to 10 times of that at the normal *** wear profile was mapped to identify the critical zone where the stress concentration is the key point in this *** surface features were examined in different regions using scanning electron microscope(SEM).Ultimately,SEM analysis showed severer damage features in the critical zone than that in the normal zone as proven by ***,the literature data presented and considered the wear features the same at any point of the wear *** this study,the normal zone was determined at a stress value of about 0.5 MPa,whereas the critical zone was at about 5.5 *** wear behaviour of these two zones showed totally different features from one another.

关键词： polymer-to-metal contact block-on-ring wear profile wear model

ballistic design and testing of a composite armour reinforced by CNTs suitable for armoured vehicles

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Defence Technology（防务技术） 2024年第2期32卷 173-195页

作者： Evangelos Ch.Tsirogiannis Evangelos Daskalakis Mohamed H.Hassan Abdalla M.omar Paulo bartolo EODH SA Research and Development DepartmentLakkoma Chalkidikis63080Greece School of Mechanical Aerospace and Civil EngineeringUniversity of ManchesterManchesterM139PLUK Singapore Centre for 3D Printing School of Mechanical and Aerospace EngineeringNanyang Technological University639798Singapore

This paper is investigating the use of composite armour reinforced by nanomaterials, for the protection of light armoured(LAV) and medium armoured military vehicles(MAV), and the interaction between the composite materials and high-performance ballistic projectiles. Four armour materials, consisted of front hybrid fibre reinforced polymer cover layer, ceramic strike-face, fibre reinforced polymer intermediate layer and the metal matrix composite reinforced backplate, were manufactured and assembled by adhesive technology. The proposed laminated protection system is suitable for armoured ground vehicles;however, it could be used as armour on ground, air and naval platforms. The design of the protection system, including material selection and thickness, was elaborated depending on the performance requirements of Level 4 + STANAG 4569 military standard(projectile 14.5 mm × 114 mm API b32) and especially on a design philosophy which is analysed with the specifications. The backplate of this new composite is a hybrid material of Metal Matrix Composite(MMC) reinforced with carbon nanotubes(CNTs), manufactured with the use of powder metallurgy technique. The composite backplate material was morphologically, mechanically and chemically analysed. Results show that all plates are presenting high mechanical properties and ballistic characteristics, compared to commonly used armour plates. Real military ballistic tests according to AEP-STANAG 4569 were carried out for the total composite armour systems. After the ballistic tests, AA2024-CNT3 showed the best protection results, compared with the other plates(AA2024-CNT1 and AA2024-CNT2), with the projectile being unable to fully penetrate the composite plate.

关键词： Passive armour protection Protective armour ballistic performance Hybrid composites Vehicle protection

Engineering nanomedicines for immunogenic eradication of cancer cells:Recent trends and synergistic approaches

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Acta Pharmaceutica Sinica b 2024年第6期14卷 2475-2504页

作者： Ahmed O.Elzoghby omar Samir Hagar E.Emam Ahmed Soliman Riham M.Abdelgalil Yomna M.Elmorshedy Kadria A.Elkhodairy Mahmoud L.Nasr Division of Engineering in Medicine and Division of Renal Medicine Department of MedicineBrigham and Women's HospitalHarvard Medical SchoolBoston 02115MAUSA Cancer Nanotechnology Research Laboratory(CNRL) Faculty of PharmacyAlexandria UniversityAlexandria 21521Egypt

Resistance to cancer immunotherapy is mainly attributed to poor tumor immunogenicity as well as the immunosuppressive tumor microenvironment(TME)leading to failure of immune *** therapeutic strategies including chemotherapy,radiotherapy,photodynamic,photothermal,magnetic,chemodynamic,sonodynamic and oncolytic therapy,have been developed to induce immunogenic cell death(ICD)of cancer cells and thereby elicit immunogenicity and boost the antitumor immune ***,many challenges hamper the clinical application of ICD inducers resulting in modest immunogenic ***,we outline the current state of using nanomedicines for boosting ICD of cancer ***,synergistic approaches used in combination with ICD inducing nanomedicines for remodeling the TME via targeting immune checkpoints,phagocytosis,macrophage polarization,tumor hypoxia,autophagy and stromal modulation to enhance immunogenicity of dying cancer cells were *** further highlight the emerging trends of using nanomaterials for triggering amplified ICD-mediated antitumor immune *** reticulum localized ICD,focused ultrasound hyperthermia,cell membrane camouflaged nanomedicines,amplified reactive oxygen species(ROS)generation,metallo-immunotherapy,ion modulators and engineered bacteria are among the most innovative *** challenges,merits and demerits of ICD inducer nanomedicines were also discussed with shedding light on the future role of this technology in improving the outcomes of cancer immunotherapy.

关键词： Immunogenic cell death Immunogenic eradication Nanomedicines Drug delivery Cancer immunotherapy Antitumor immunity T cells Tumor associated antigens Synergistic immune response

bilateral Avascular Necrosis of the Femoral Head in Renal Transplant Recipient: A Case Report

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Open Journal of Nephrology 2024年第2期14卷 253-261页

作者： Imane Saidi Moulay omar Lamrani Naima Ouzeddoun Tarik bouattar Department of Nephrology-Dialysis-Renal Transplantation IbnSina University Hospital Rabat Morocco Faculty of Medicine and Pharmacy Mohammed V University Rabat Rabat Morocco Department of Traumatology IbnSina University Hospital Rabat Morocco

Osteoarticular complications are common after renal transplantation. The complications may result from the bone condition prior to transplantation or the iatrogenic effects of the treatments administered. These complications lead to significant morbidity and mortality, in addition to chronic pain and functional impairment. We report the clinical case of bilateral avascular necrosis (AVN) of the femoral head in a kidney transplant recipient. Clinical Case: 53-year-old male with a history of chronic hypertension. He underwent chronic hemodialysis for 12 months and was treated with Entecavir for chronic hepatitis b. The patient received a kidney transplant from a non-related living donor. Induction therapy included Thymoglobulin along with tapered corticosteroids, reaching a dose of 5 mg/day after 3 months, Mycophenolate mofetil (2 g/day), and Tacrolimus adjusted based on residual levels. There was good recovery of renal graft function. After six months, the patient reported bilateral hip pain and functional impairment of both lower limbs. Pelvic X-rays showed signs suggestive of bilateral AVN of the femoral heads. The diagnosis was confirmed by MRI. The patient underwent right hip drilling and total left hip replacement (THR). A right THR was performed a year later. Conclusion: AVN constitutes a frequent cause of morbidity and mortality after RT. The pathophysiology of osteonecrosis remains complex and multifactorial. We emphasize the importance of conducting a thorough assessment of bone health in patients both before and after RT.

关键词： Avascular Necrosis Femoral Head Osteoarticular Complications Renal Transplant

A novel saliva-based miRNA profile to diagnose and predict oral cancer

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International Journal of Oral Science 2024年第1期16卷 97-109页

作者： Jaikrishna balakittnen Chameera Ekanayake Weeramange Daniel F.Wallace Pascal H.G.Duijf Alexandre S.Cristino Gunter Hartel Roberto A.barrero Touraj Taheri Liz Kenny Sarju Vasani Martin batstone omar b.eik Chamindie Punyadeera Saliva&Liquid biopsy Translational Laboratory Griffith Institute for Drug DiscoveryGriffith UniversityNathanQLDAustralia Department of Medical Laboratory Sciences Faculty of Allied Health SciencesUniversity of JaffnaJaffnaSri Lanka Menzies Health Institute Griffith UniversityGold CoastQLDAustralia School of biomedical Sciences Faculty of HealthQueensland University of TechnologyBrisbaneQLDAustralia Centre for Cancer biology Clinical and Health SciencesUniversity of South Australia&SA PathologyAdelaideSAAustralia Institute of Clinical Medicine Faculty of MedicineUniversity of OsloOsloNorway Department of Medical Genetics Oslo University HospitalOsloNorway Griffith Institute for Drug Discovery Griffith UniversityNathanQLDAustralia QIMR berghofer Medical Research Institute Statistics UnitBrisbaneQLDAustralia School of Public Health The University of QueenslandBrisbaneQLDAustralia School of Nursing Queensland University of TechnologyBrisbaneQLDAustralia eResearch Research InfrastructureAcademic DivisionQueensland University of TechnologyBrisbaneQLDAustralia Department of Anatomical Pathology Royal Brisbane and Women’s HospitalHerstonQLDAustralia Faculty of Medicine The University of QueenslandBrisbaneQLDAustralia Royal brisbane and Women’s Hospital Cancer Care ServicesHerstonQLDAustralia Department of Otolaryngology Royal Brisbane and Women’s HospitalHerstonQLDAustralia Department of Oral and Maxillofacial Surgery Royal Brisbane and Women’s HospitalHerstonQLDAustralia

Oral cancer (OC) is the most common form of head and neck cancer. Despite the high incidence and unfavourable patient outcomes, currently, there are no biomarkers for the early detection of OC. This study aims to discover, develop, and validate a novel saliva-based microRNA signature for early diagnosis and prediction of OC risk in oral potentially malignant disorders (OPMD).The Cancer Genome Atlas (TCGA) miRNA sequencing data and small RNA sequencing data of saliva samples were used to discover differentially expressed miRNAs. Identified miRNAs were validated in saliva samples of OC (n=50), OPMD (n=52), and controls(n=60) using quantitative real-time PCR. Eight differentially expressed miRNAs (miR-7-5p, miR-10b-5p, miR-182-5p, miR-215-5p,miR-431-5p, miR-486-3p, miR-3614-5p, and miR-4707-3p) were identified in the discovery phase and were validated. The efficiency of our eight-miRNA signature to discriminate OC and controls was:area under curve (AUC):0.954, sensitivity:86%, specificity:90%,positive predictive value (PPV):87.8%and negative predictive value (NPV):88.5%whereas between OC and OPMD was:AUC:0.911,sensitivity:90%, specificity:82.7%, PPV:74.2%and NPV:89.6%. We have developed a risk probability score to predict the presence or risk of OC in OPMD patients. We established a salivary miRNA signature that can aid in diagnosing and predicting OC,revolutionising the management of patients with OPMD. Together, our results shed new light on the management of OC by salivary miRNAs to the clinical utility of using miRNAs derived from saliva samples.

关键词： specificity salivary diagnosis

Evolution of heart transplant donor characteristics in the 21st century: A United States single center’s experience

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World Journal of Transplantation 2024年第3期14卷 22-29页

作者： Alexander M Spring Christiana Gjelaj Shivank Madan Snehal R Patel omar Saeed Sandhya Murthy Yogita Rochlani Daniel b Sims Sasha Vukelic Stephen J Forest Jamil F borgi Daniel J Goldstein Ulrich P Jorde Montefiore-Einstein Center for Heart and Vascular Care Montefiore Medical CenterAlbert Einstein College of MedicineBronxNY 10467United States Division of Cardiothoracic Surgery Tulane UniversityNew OrleansLA 70112United States

Despite a record setting number of heart transplants performed annually,the national donor shortage continues to plague transplant teams across the United *** we describe the barriers to adaptation of numerous“non-traditional”orthotopic heart transplant donor characteristics including donors with hepatitis C virus,those meeting criteria for donation after cardiac death,donors with coronavirus disease 19 infection,donors with the human immunodeficiency virus,and grafts with left ventricular systolic *** center’s objective was to increase our transplant volume by expanding our donor pool from“traditional”donors to these“non-traditional”*** detail how medical advances such as certain laboratory studies,pharmacologic interventions,and organ care systems have allowed our center to expand the donor pool thereby increasing transplantation volume without adverse effects on outcomes.

关键词： Orthotopic heart transplantation Hepatitis C virus COVID-19 Left ventricular systolic dysfunction Human immunodeficiency virus Donation after cardiac death

VISCOMETRIC INVESTIGATIONS OF POLYVINYLPYRROLIDONE IN MIXED SOLVENTS AND WITH VARYING TEMPERATURE

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Chinese Journal of Polymer Science 2005年第4期23卷 367-371页

作者： omar Melad omar Abu-Tiem Rajai baraka Chemistry Department

The viscosity behavior of polyvinylpyrrolidone(PVP)has been determined at 25℃ in mixed solvents comprising water/dimethylformamide(DMF)and water/methanol(MeOH).Analysis of the data has considered the PVP as being both host and guest polymer in *** intrinsic viscosity of PVP in DMF is higher than in water and in MeOH,but also increases in a mixed solvent with high water content because of the effect of polymer-solvent *** was also found that the intrinsic viscosity of PVP at finite concentration,[η_(pvp)]_c decreases with an increase in the concentration of PVP in *** viscosity behavior of PVP in a mixed solvent is affected by the concentration-dependent intermolecular excluded volume effect,which can be quantitatively expressed by the parameter,b_Y,which reflects the shrinkage of PVP chain coils,resulting in a decrease of[η_(pvp)]_*** effect of temperature on the viscosity behavior of PVP in MeOH shows that the interaction parameter increases up to a maximum value,and then decreases after a certain temperature.

关键词： Polyvinylpyrrolidone Intermolecular excluded volume effect Intrinsic viscosity

Reintegrating nanogranitoid inclusion composition to reconstruct the prograde history of melt-depleted rocks

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Geoscience Frontiers 2019年第2期10卷 517-525页

作者： omar bartoli Department of Geosciences University of Padova

A recent fascinating development in the study of high-grade metamorphic basements is represented by the finding of tiny inclusions of crystallized melt(nanogranitoid inclusions) hosted in peritectic phases of migmatites and granulites. These inclusions have the potential to provide the primary composition of crustal melts at the source. A novel use of the recently-published nanogranitoid compositional database is presented here. Using granulites from the world-renowned Ivrea Zone(NW Italy) on which the original melt-reintegration approach has been previously applied, it is shown that reintegrating melt inclusion compositions from the published database into residual rock compositions can be a further useful method to reconstruct a plausible prograde history of melt-depleted rocks. This reconstruction is fundamental to investigate the tectonothermal history of geological terranes.

关键词： Nanogranitoids Melt-reintegration Granulite High-temperature metamorphism

Design of a Novel THz Modulator for b5G Communication

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Computers, Materials & Continua 2022年第10期73卷 1055-1066页

作者： omar A.Saraereh Department of Electrical Engineering Faculty of EngineeringThe Hashemite UniversityZarqa13133Jordan

Wireless data traffic has expanded at a rate that reminds us of Moore’s prediction for integrated circuits in recent years,necessitating ongoing attempts to supply wireless systems with ever-larger data rates in the near future,despite the under-deployment of 5G ***(THz)communication has been considered a viable response to communication blackout due to the rapid development of THz technology and *** communication has a high frequency,which allows for better *** is a fast expanding and evolving industry,driven by an increase in wireless traffic volume and data transfer speeds.A THz modulator based on a hybrid metasurface was devised and built in this *** device’s modulation capabilities were modelled and proved *** electrolyte is an ion-gel medium implanted between graphene and metasurface,and the active material is *** the metasurface,the interaction between the THz wave and graphene is ***,an external bias voltage was employed to actively regulate the THz waves by tuning the electrical conductivity of *** results show that with a minimal bias voltage,the device can achieve a modulation depth of up to 73%at the resonant ***,during the modulation process,the resonance frequency remains almost *** a result,the proposed gadget offers a unique tool for substantial THz amplitude modulation at low voltages.

关键词： Terahertz communication modulator metasurface graphene