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Modelling of temperature and strain rate dependent behaviour of pearlitic steel in block braked railway wheels

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Railway Engineering Science 2021年第4期29卷 362-378页

作者： Ali Esmaeili Johan Ahlstrom Magnus Ekh dimitrios Nikas Tore Vernersson CHARMEC/Department of Industrial and Materials Science Chalmers University of TechnologyGothenburgSweden Now at Department of Engineering and Physics Karlstad UniversityKarlstadSweden CHARMEC/Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden

Block braked railway wheels are subjected to thermal and rolling contact *** thermal loading results in high temperatures and thermal stresses which cause slow time dependent processes such as creep,relaxation and static recovery of the wheel *** the same time,the rolling contact loading implies a very fast mechanical load *** paper is focused on material modeling of pearlitic steel for a wide range of loading rates at elevated *** starting point is a viscoplasticity model including nonlinear isotropic and kinematic *** Delobelle overstress function is employed to capture strain rate dependent response of the *** model also includes static recovery of the hardening to capture slower viscous(diffusion dominated)behaviour of the *** for the pearlitic wheel steel ER7 in terms of cyclic strain-controlled uniaxial tests with hold-time,uniaxial ratchetting tests including rapid cycles and biaxial cyclic tests with tension/compression and torsion are used to calibrate the material *** experiments were performed under isothermal conditions at different *** the ratchetting tests,higher loading rates are obtained and these have been used to calibrate the high strain rate response of the viscoplasticity *** paper is concluded with a numerical example of a block braked wheel where the importance of accounting for the viscoplasticity in modelling is highlighted.

关键词： Block braking High temperatures Pearlitic steel Railway wheels Viscoplasticity

Surgical treatment outcome of painful traumatic neuroma of the infrapatellar branch of the saphenous nerve during total knee arthroplasty

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World Journal of Orthopedics 2021年第12期12卷 1008-1015页

作者： Byron Chalidis dimitrios Kitridis Panagiotis Givissis The First Orthopaedic Department Aristotle University of ThessalonikiSchool of MedicineThessaloniki 57010Greece

BACKGROUND Development of infrapatellar saphenous neuroma(ISN)is a well-recognized reason for knee pain following total knee arthroplasty(TKA).So far,very few studies have addressed the development of painful ISN after TKA and its impact on functional outcome and patient *** To present the results of surgical treatment for ISN after primary TKA,the level of pain relief,and the improvement of knee motion and *** Fifteen patients(13 women,2 men)with persistent medial pain for more than six months after primary TKA,due to osteoarthritis,underwent surgical excision of *** diagnosis was confirmed with the presence of Tinel’s sign along the course of the infrapatellar branch of the saphenous nerve and with pain relief after selective nerve block using local *** loosening,malalignment,instability and infection were excluded systematically in all patients as a source of *** relief in terms of visual analog scale(VAS),active knee range of motion(ROM),and the Knee Society Score(KSS)for pain and function were evaluated preoperatively and at least six months *** The mean patients’age was 71.3±5.4 years *** mean interval between TKA and neuroma excision was 10 mo(range,6 to 14 mo),while the mean follow-up was 8 mo(range:6 to 11 mo).All 15 patients experienced almost complete immediate pain relief and resolution of allodynia and hyperesthesia after *** on the VAS scale improved from 8.6±1.3 preoperatively to 0.8±0.9 at the final follow-up(P=0.001).KSS pain and function scores were improved from 49.3±5.9 and 62.7±12.8 before surgery to 91.8±4.2 and 75.3±11.3 after surgery,respectively(P=0.001 and P=0.015).Active knee ROM was also increased postoperatively from 96±4 to 105±6 degrees(P=0.001).There were no complications and no further operations *** ISN should be considered a potential cause of persistent pain following *** excision not only provides immediate pain relief an

关键词： Total knee arthroplasty Infrapatellar branch of saphenous nerve Neuroma Neurogenic pain Knee osteoarthritis

Tibial tubercle osteotomy in revision total knee arthroplasty: A systematic review

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World Journal of Orthopedics 2020年第6期11卷 294-303页

作者： Byron Chalidis dimitrios Kitridis Panagiotis Givissis 1^st Orthopaedic Department Aristotle University of ThessalonikiGeorge Papanikolaou HospitalThessaloniki 55210Greece

BACKGROUND Tibial tubercle osteotomy(TTO) is a well-established surgical technique to deal with a stiff knee in revision total knee arthroplasty(RTKA). However, several reports have described potential osteotomy-related complications such as nonunion, tibial tubercle migration and fragmentation, and metalware related *** To evaluate the literature and estimate the efficiency of TTO in RTKA in terms of osteotomy union, knee mobility and *** MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials were investigated for completed studies until February 2020. The principle outcome of the study was the incidence of union of the osteotomy. Secondary outcomes were the knee range of motion as well as the TTO-related and overall procedure complication *** Fifteen clinical studies with a total of 593 TTOs were included. The TTO union rate was 98.1%. Proximal migration and anterior knee pain were the most common TTO-related complications accounting for 6.9% and 6.4% of all cases,respectively. However, only 2.2% of cases suffering from anterior knee pain needed hardware removal. Knee flexion was improved from 82.9° preoperatively to 100.1° postoperatively and total knee range of motion was increased from 73.4° before surgery to 97° after surgery. Stiffness requiring manipulation under anesthesia was recorded in 4.6% of cases. No major complications were *** The current systematic review supports the use of TTO in RTKA, as it is associated with high union rate, significant improvement in knee motion and low osteotomy-related complication risk that rarely leads to secondary tibial tubercle procedures.

关键词： Tibial tubercle osteotomy Knee flexion Extension lag Union Revision total knee arthroplasty Stiff knee

Antithrombotic therapy in TAVI

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Journal of Geriatric Cardiology 2018年第1期15卷 66-75页

作者： Manolis Vavuranakis Konstantinos Kalogeras Angelos Michail Kolokathis dimitrios Vrachatis Nikolaos Magkoutis Gerasimos Siasos Euaggelos Oikonomou Maria Kariori Theodoros Papaioannou Maria Lavda Carmen Moldovan Ourania Katsarou dimitrios Tousoulis The First Department of Cardiology Hippokration Hospital Medical School National & Kapodistrian University of Athens Ilioupoli Greece

Transcatheter aortic valve implantation （TAVI） carries a significant thromboembolic and concomitant bleeding risk, not only during the procedure but also during the periprocedural period. Many issues concerning optimal antithrombotic therapy after TAVI are still under debate. In the present review, we aimed to identify all relevant studies evaluating antithrombotic therapeutic strategies in relation to clinical outcomes after the procedure. Four randomized control trials （RCT） were identified analyzing the post-TAVI antithrombotic strategy with all of them utilizing aspirin lifelong plus clopidogrel for 3-6 months. Seventeen registries have been identified, with a wide variance among them regarding baseline characteristics, while concerning antiplatelet therapy, clopidogrel duration was ranging from 3-12 months. Four non-randomized trials were identified, comparing single vs. dual antiplatelet therapy after TAVI, in respect of investigating thromboembolic outcome events over bleeding complications. Finally, limited data from a single RCT and a retrospective study exist with regards to anticoagulant treatment during the procedure and the optimal antithrombotic therapy when concomitant atrial fibrillation. In conclusion, due to the high risk and frailty of the treated population, antithrombotic therapy after TAVI should be carefully evaluated. Diminishing ischaemic and bleeding complications remains the main challenge in these patients with further studies to be needed in this field.

关键词： Antiplatelets Antithrombotic Bleeding Stroke Transcatheter aortic valve implantation

Synthesis of carbon nanotubes loaded hydroxyapatite: Potential for controlled drug release from bone implants

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Journal of Advanced Ceramics 2016年第3期5卷 232-243页

作者： Lisa COSTANTINI Nikolaos BOUROPOULOS dimitrios G.FATOUROS Ioanna KONTOPOULOU Marta ROLDO School of Pharmacy and Biomedical Science University of Portsmouth St Michael's BuildingWhite Swan Road Portsmouth UK Department of Materials Science University of Patras 26504 Rio Patras GreeceFoundation for Research and Technology Hellas-Institute of Chemical Engineering and High Temperature Chemical Processes—FORTH/ICEHT P.O.Box 1414 GR 26504 Patras Greece Department of Pharmaceutical Technology School of Pharmacy Aristotle University of ThessalonikiGR-54124 Thessaloniki Greece Department of Materials Science University of Patras 26504 Rio Patras Greece

Carbon nanotubes (CNTs) can support the building of flexible and porous scaffolds for bone regeneration. Various studies have looked at the mixing of CNTs with hydroxyapaptite for the formulation of bone implants. In the present work, we report the one step preparation and characterisation of chitosan/hydroxyapatite/CNTs composite materials obtained by wet precipitation of hydroxyapatite (HA) in the presence of chitosan or its amphiphilic derivative N-octyl-O-sulphate chitosan and CNTs. The in situ precipitation of HA assured inclusion of the polysaccharide and the CNTs in the HA structure and provided materials with the ability to control the release of different model drugs.

关键词： carbon nanotubes (CNTs) hydroxyapatite (HA) composites bone regeneration chitosan

After Administration of Intravenous Epinephrine for bee Sting-induced Anaphylaxis： Kounis Syndrome or Epinephrine Effect？

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Chinese Medical Journal 2016年第4期129卷 500-501页

作者： Nicholas G Kounis George D Soufras dimitrios Lianas Nicholas Patsouras Department of Cardiology University of Patras Medical School Patras 26221 Achaia Greece

To the Editor： In the very important report published in Chinese Medical Journal,a 50-year-old male patient, stented with a bare metal stent followed by 3 overlapping drug-eluting stents, developed anaphylactic reaction following a bee sting that was treated with intravenous 0. I mg epinephrine at a 1 ： 100,000 together with intravenous methylprednisolone, chlorpheniramine maleate, and ranitidine. He developed, immediately after, an anterior wall myocardial infarction, and subsequent coronary arteriography revealed total occlusion in the proximal left anterior descending stent and 90% stenosis with tissue growth in the mid-stent. The authors concluded that the acute myocardial infarction occurred due to acute stent thrombosis caused by exogenous epinephrine administration. This report, however, raises important questions related to the cause and pathophysiology of these events.

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Primary adrenal Ewing sarcoma:A systematic review of the literature

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世界临床病例杂志 2023年第28期11卷 6782-6791页

作者： dimitrios K Manatakis Ioannis Tsouknidas Emmanouil Mylonakis Nikolaos Tasis Maria Ioanna Antonopoulou Vasileios Acheimastos Aikaterini Mastoropoulou dimitrios P Korkolis 2^(nd)Department of Surgery Athens Naval and Veterans HospitalAthens 11521Greece General Surgery Lankenau Medical CenterMain Line HealthWynnewoodPA 19096United States Department of Surgical Oncology St Savvas Cancer HospitalAthens 11522Greece Department of Surgery Naval Hospital of CreteChania 73200Greece Department of Pediatrics Stony Brook University HospitalStony BrookNY 11794United States

BACKGROUND Ewing sarcoma(ES)is a malignant neoplasm of neuroectodermal origin and is commonly observed in children and young *** musculoskeletal system is the main body system impacted and ES is rarely seen in the visceral organs particularly the adrenal *** To present a comprehensive review of primary adrenal ES,with emphasis on diagnosis,therapy and oncological *** A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses ***/MEDLINE,EMBASE and Google Scholar bibliographic databases were searched to identify articles from 1989 to 2022 and included patients with ES/primitive neuroectodermal tumor(PNET)of the adrenal ***,Google Scholar and EMBASE medical databases were searched,combining the terms“adrenal”,“ES”and“PNET”.Demographic,clinical,pathological and oncological data of patients were analyzed by SPSS version *** A total of 52 studies were included for review(47 case reports and 5 case series)with 66 patients reported to have primary adrenal *** age at diagnosis was 26.4±15.4 years(37.9%males,57.6%females,sex not reported in 3 cases).The most frequent complaint was abdominal/flank pain or discomfort(46.4%)followed by a palpable mass(25.0%),and the average duration of symptoms was 2.6±3.1 *** imaging modality of choice was computed tomography scan(81.5%),followed by magnetic resonance imaging(20.4%).Preoperative staging revealed that 17 tumors(27.9%)were metastatic and 14 patients had inferior vena cava or renal vein neoplastic thrombus at initial *** adrenalectomy was performed in the majority of cases(80.0%),of which 27.9%required more extensive *** invasive surgery was attempted in 8.2%of *** surgical resection was achieved in 89.4%of the *** therapy was administered to 32 patients,in the form of chemotherapy(62.5%),radiotherapy(3.1%)or combination(34.4%).Median overall s

关键词： Ewing sarcoma Primary adrenal tumor Adrenalectomy

Vascular endothelial growth factor for the treatment of femoral head osteonecrosis: An experimental study in canines

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World Journal of Orthopedics 2018年第9期9卷 120-129页

作者： Zoe H Dailiana Nikolaos stefanou Lubna Khaldi Georgios Dimakopoulos James R Bowers Cristian Fink James R Urbaniak Department of Orthopaedic Surgery Faculty of Medicine University of Thessalia Department of Orthopaedic Surgery Duke University Medical Center Department of Pathology "Saint Savvas" AntiCancer Hospital Medical Statistics Epirus Science and Technology Park Campus of the University of Ioannina Emerge Ortho Independence Park Gelenkpunkt Sports and Joint Surgery Research Unit of Orthopedic Sports Medicine and Injury Prevention Institute for Sports Medicine Alpine Medicine and Health Tourism (ISAG)UMIT

AIM To evaluate the treatment of osteonecrosis of the femoral head(ONFH) with the use of vascular endothelial growth factor(VEGF).METHODS In 30 mature beagles(6 groups of 5 beagles) ONFH was induced cryosurgically and one of the following solutions was administered locally in the femoral head(FH) in each group: Single injection of 500 μg VEGF(t-VEGFμ group); single injection of 500 ng VEGF(t-VEGFn group); continuous delivery of 500 μg VEGF through osmotic micropump(t-VEGFpump-μ group); continuous delivery of 500 ng VEGF through osmotic micropump(t-VEGFpump-n group); single injection of 0.9% sodium chloride(t-NS group), while one group that served as control group did not receive any local solution(No-t group). FHs were retrieved 12 wk postoperatively, underwent decalcification and hematoxylin/eosin and toluidine blue staining. In two canines per group, one half of FH was processed without decalcification and stained with modified Masson Trichrome. Histological sections were observed by light microscopy and measured with a semi-automatized bone histomorphometry system and Bone Volume/Total Volume(BV/TV), Marrow Volume/Total Volume(MaV/TV), and Trabecular Thickness(TbT h) were assessed. Standard and robust tests(Welch, Brown Forsythe) of analysis of variance along with multiple comparisons, were carried out among the *** The untreated(No-t) group had signs of osteonecrosis, whereas the VEGF groups revealed reversal of the osteonecrosis. Statistical analysis of the decalcified specimens revealed a significantly better BV/TV ratio and a higher Tb Th between the VEGF treatment groups(except the t-VEGFn group) and the No-t group or the control t-NS group. Single dose 500 μg VEGF group had significantly better BV/TV ratio and higher Tb Th when compared to the No-t group(50.45 ± 6.18 vs 29.50 ± 12.27, P = 0.002 and 151.44 ± 19.07 vs 107.77 ± 35.15, P = 0.161 respectively) and the control t-NS group(50.45 ± 6.18 vs 30.9 ± 6.67, P = 0.004 and 151.44 ± 19.07 vs

关键词： Osteonecrosis Vascular endothelial growth factor Avascular necrosis Femoral head Osteogenesis Animal model

Beta-blocker treatment in heart failure patients with atrial fibrillation:challenges and perspectives

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Journal of Geriatric Cardiology 2021年第5期18卷 362-375页

作者： Emmanouil Chourdakis Ioanna Koniari dimitrios Velissaris Grigorios Tsigkas Nikolaos G Kounis Neriman Osman Krankenhaus der Barmherzigen Brüder Trier Germany Manchester Heart Institute Manchester University Foundation TrustManchesterUnited Kingdom Department of Internal Medicine University Hospital of PatrasPatrasGreece Cardiology Department University Hospital of PatrasPatrasGreece

Heart failure(HF)and atrial fibrillation(AF)are common conditions that share similar clinical phenotype and frequently *** classification of HF in patients with preserved ejection fraction(>50%,HFpEF),midrange reduced EF(40%−49%,HFmrEF)and reduced EF(<40%,HFrEF)are crucial for optimising the therapeutic approach,as each subgroup responds *** constitute an important component of our pharmacological regimen for chronic *** administration is reccomended in patients with HF with reduced ejection fraction in stable sinus rhythm,due to improvement of symptoms,the better long termoutcome and *** beneficial role of betablocker use in patients with preserved EF still remain unclear,as no treatment showed a positive impact,regarding morbidity or mortality *** presence of AF in HF patients increases as the disease severity evolves and is associated with a higher rate of cardiovascular morbidity and *** more question is the use of betablocker in HF patients irrespective of EF and concomitant *** are many conflicting data and publications,regarding the beta blocker benefit in this ***,it is supported an attenuation of betablockers beneficial effect in HF patients with AF.A design of more randomised trials/studies with HF patients and concomitant AF may improve our clinical approach of betablockers use and identify the patients with HF,who mostly profit from an invasive approach.

关键词： treatment evolve mostly