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Effect of Rotational and Sliding Motions on Friction and Degeneration of Articular cartilage under Dry and Wet Friction

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Journal of Bionic Engineering 2015年第3期12卷 464-472页

作者： ahmet c. cilingir Department of Mechanical Engineering Sakarya University 54187 Sakatya Turkey

Understanding the tribological properties of articular cartilage allows scientists to evaluate degenerative joint diseases and develop new treatment techniques. The objectives of this study are to demonstrate the detrimental effect of rotational motion under both dry and wet friction and to evaluate the friction and wear behavior of bovine articular cartilage with sliding and rotational testing configurations that represent fluid film and boundary lubrication mechanisms, respectively. The articular cartilage pin and plate samples were harvested from healthy adult bovine and then tested on a self-made friction and wear simulator. cartilage samples were subjected to sliding and rotational motions under constant load. Friction coefficients and wear factors were calculated under three conditions： using bovine serum, phosphate buffered saline and with no lubricant present. The friction coefficient and wear factor of the articular cartilage were significantly increased with rotational motion under both dry and wet friction. Using bovine serum as lubricant in the sliding testing configuration the friction coefficient and wear factor of articular cartilage were both decreased. A similar decrease in the tribological properties of cartilage was initially observed for the rotational testing configuration with bovine serum; however, the friction coefficient and wear factor were increased after 150,000 cycles. In the absence of lubricant, the articular cartilage was entirely worn on contact area in both sliding and rotational testing configurations. Bovine serum proved an effective fluid film lubricant for articular cartilage surfaces.

关键词： articular cartilage rotational motion sliding motion dry friction wet friction wear

BSN:Photometric Light curve Analysis of Two contact Binary Systems LS Del and V997 cyg

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Research in Astronomy and Astrophysics 2024年第4期24卷 192-213页

作者： Atila Poro Mehmet Tanriver Elham Sarvari Shayan Zavvarei Hossein Azarara Laurent corp Sabrina Baudart Asma Ababafi Nazanin Kahali Poor Fariba Zare ahmet Bulut ahmet Keskin Astronomy Department of the Raderon AI Lab. BurnabyBC.Canada Department of Astronomy and Space Science Faculty of ScienceErciyes UniversityKayseri TR-38039Turkiye Erciyes University Astronomy and Space Science Observatory Application and Research CenterKayseri TR-38039Turkiye Independent Astrophysics Researcher TehranIran Department of Physics Shahid Beheshti UniversityTehranIran Faculty of Physics Shahid Bahonar University of KermanP.O.Box 76175KermanIran Double Stars committee SociétéAstronomique de FranceParisFrance Dez Astronomical Association Khouzestan ProvinceDezfulIran Department of Physics Amirkabir University of TechnologyTehranIran Department of Physics Faculty of SciencesCanakkale Onsekiz Mart UniversityTerzioglu KampusuTR-17020CanakkaleTurkiye Astrophysics Research center and Observatory Canakkale Onsekiz Mart UniversityTerzioğlu KampusuTR-17020CanakkaleTürkiye

The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Ground-based photometric observations were performed at two observatories in *** used the Transiting Exoplanet Survey Satellite(TESS)data for extracting times of minima and light curve analysis of the targe *** O-c diagram for both systems displays a parabolic *** Del and V997 cyg’s orbital periods are increasing at rates of dP/dt=7.20×10^(-08)days yr^(-1)and dP/dt=2.54×10^(-08)days yr^(-1),respectively Therefore,it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt=-1.96×10^(-7)M_(⊙)yr^(-1)for the LS Del system,and dM/dt=-3.83×10^(-7)M_(⊙)yr-1for V997 *** parameters of a third possible object in the system are also *** PHysics Of Eclipsing BinariEs Python code was used to analyze the light *** light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve *** mass ratio fill-out factor,and star temperature all indicate that both systems are contact binary types in this *** methods were applied to estimate the absolute parameters of the systems:one method relied on the parallax of Gaia DR3,and the other used a P-M *** positions of the systems are also depicted on the M-L,M-R q-L_(ratio),and logM_(tot)-logJ_(0)*** recommend that further observations and investigations be done on the existence of a fourth body in this system.

关键词： (stars:)binaries:eclipsing methods:observational stars:individual(LS Del and V997 cyg)

Respiratory Mechanics, Respiratory Muscle Strength, control of Ventilation and Gas Exchange in Patients with Autoimmune Liver Disease

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Open Journal of Respiratory Diseases 2024年第2期14卷 25-38页

作者： ahmet Baydur Jacob Korula Divisions of Pulmonary Critical Care and Sleep Medicine Los Angeles USA Keck School of Medicine University of Southern California Los Angeles California USA Liver Diseases Rancho Los Amigos National Rehabilitation Center Downey California USA

Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-autoimmune liver disease and control subjects. These findings were then related to control of ventilation and gas exchange. A secondary objective was to assess respiratory muscle strength and gas exchange and their relation to respiratory mechanics. Methods: Measurements included respiratory elastance and resistance using the passive relaxation method. Pulmonary function, gas exchange and control of ventilation were assessed using standard methods. Results: a) compared to control subjects, Ers in patients with liver disease was on average 50% greater than in controls;b) mean respiratory resistance, expressed as the respiratory constants, K1 and K2 in the Rohrer relationship, Pao/V’ = K1 + K2V’, was not different from control resistance;c) mean maximal inspiratory and maximal expiratory pressures averaged 36% and 55% of their respective control values;d) inspiratory occlusion pressure in 0.1 sec (P0.1) was increased and negatively associated with FVc;and e) increases in P0.1, mean inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the increase in ventilatory drive. Despite inspiratory muscle weakness in patients, P0.1/Pimax averaged 5-fold higher than in control subjects. conclusions: Despite inspiratory muscle weakness and a V’E similar to that in normal subjects, central drive is increased in patients with chronic liver disease. The increase in ventilatory drive is related to smaller lung volumes and weakly associated with increase in respiratory elastance. Findings confirm that P0.1 is a reliable measure of central drive and is an approach that can be used in the evaluation of control of ventilation in patients with chronic liver dis

关键词： Autoimmune Liver Disease control of Ventilation Occlusion Pressure Passive Relaxation Method Primary Biliary cirrhosis Respiratory Elastance Respiratory Resistance

Rhabdomyolysis-related acute kidney injury in patients with cOVID- 19

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World Journal of Virology 2024年第3期13卷 76-81页

作者： ahmet Murt Mehmet Riza Altiparmak Department of Nephrology clinic Istanbul University-CerrahpasaCerrahpasa Medical FacultyIstanbul 34000Türkiye Department of Internal Medicine Division of NephrologyIstanbul UniversityIstanbul 34000Türkiye

BAcKGROUND Viral and bacterial infections may be complicated by rhabdomyolysis,which has a spectrum of clinical presentations ranging from asymptomatic laboratory abnor-malities to life-threatening conditions such as renal *** viral injury as well as inflammatory responses may cause rhabdomyolysis in the course of coronavirus disease 2019(cOVID-19).When presented with acute kidney injury(AKI),rhabdomyolysis may be related to higher morbidity and *** To compare rhabdomyolysis-related AKI with other AKIs during *** A total of 115 patients with cOVID-19 who had AKI were evaluated *** patients had a definite diagnosis of rhabdomyolysis(i.e.,creatine kinase levels increased to>5 times the upper normal range with a concomitant increase in transaminases and lactate dehydrogenase).These patients were aged 61.0±19.1 years and their baseline creatinine levels were 0.87±0.13 mg/*** were treated according to national cOVID-19 treatment *** were compared with patients with cOVID-19 who had AKI due to other *** For patients with rhabdomyolysis,creatinine reached 2.47±1.17 mg/dL during follow-up in *** these patients,13.3%had AKI upon hospital admission,and 86.4%developed AKI during hospital *** peak c-reactive protein reached as high as 253.2±80.6 mg/L and was higher than in patients with AKI due to other reasons(Pcalcitonin levels were also higher for patients with rhabdomyolysis(P=0.02 and P=0.002,respective-ly).The mortality of patients with rhabdomyolysis was calculated as 73.3%,which was higher than in other patients with AKI(18.1%)(P=0.001).cONcLUSION Rhabdomyolysis was present in 13.0%of the patients who had AKI during cOVID-19 ***-related AKI is more proinflammatory and has a more mortal clinical course.

关键词： Rhabdomyolysis Acute kidney injury cOVID-19 SARS-coV-2 creatine kinase

Newly identified Au-Ag-Bi-Te mineralization in the Aydindere skarn Fe and cu deposit， Giresun， NE Turkey: implications of gold mineralization during retrograde skarn evolution

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Journal of Earth Science 2024年

作者： ahmet Sasmaz Vitaliy Sukach Serhiy Bondarenko Hryhorii Aleksiienko Hengameh Erfanian Kaseb Bilge Sasmaz Sergiy Kurylo Oleksandr Hrinchenko Volodymyr Somka Panagiotis Voudouris Department of Geology， Firat University Faculty of Geology and Geoenvironment， National and Kapodistrian University of Athens Mineralogy and Ore Formation of National Academy of Science， M.P.Semenenko Institute of Geochemistry 3. Department of Petroleum Engineering， Eqbal Lahoori Institute of Higher Education

This study investigates the mineralogy and mineral-chemistry of a newly discovered Au-Ag-Bi-Te mineralization at the Aydindere Fe-cu skarn deposit， within the Pontides Tectonic Unit， northeastern Turkey. The mineralization is developed in the skarn zone at the contact between Upper cretaceous andesite-pyroclastic rocks and a Paleocene-Eocene I-type granitoid. The principal ore minerals of the Aydindere Fe-cu deposit are oxides (magnetite)， sulfides (pyrite-chalcopyrite-galena-sphalerite)， tellurides/sulfotellurides (tetradymite， hessite)， sulfosalts (wittichenite， emplectite， aikinite) and native gold-electrum. Skarn minerals include anhydrous phases (garnet) formed in a prograde stage and hydrous phases (amphibole， epidote， chlorite)， which were formed in a retrograde stage in association with quartz， adularia， apatite and late calcite. Sulfides， tellurides and sulfosalts are introduced during the retrograde stage. The Au-Ag-Bi-Te mineralization was detected for the first time within the western ore body of the Aydindere deposit， and occurs in calcite-bearing sulfide bodies that cut magnetite-garnet-amphibole-epidote skarns with magnetite ores of different grade， including massive magnetite. chlorite geothermometry indicates formation of the Au-Ag-Bi-Te mineralization at temperatures between 300 and 250 °c， during the retrograde skarn evolution. Assuming the temperature is ～275°c， logfS2= -10.5 to -13， logfO2= -37 to -33， and logfTe2values range from approximately -12 to -8.5 were estimated. The available mineralogical and geological data (presences of magnetite， oxidized-type tellurides/sulfotellurides， and andraditic garnets， and absence of pyrrhotite and arsenopyrite) suggest that Aydindere is an oxidized Au-bearing skarn deposit. The discovery of Au-Ag-Bi-Te mineralization at Aydindere increases its productivity and requires more detailed exploration in the deposit for precious (Au， Ag) and critical (Bi， Te) metals.

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Radiological findings of February 2023 twin earthquakes-related spine injuries

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World Journal of Radiology 2024年第9期16卷 398-406页

作者： Ayşenur Bolukçu ahmet Gürkan Erdemir İlkay Sedakatİdilman Adalet Elçin Yildiz GökçenÇobanÇifçi Mehmet Ruhi Onur Erhan Akpinar Department of Radiology Hacettepe UniversityFaculty of MedicineAnkara 06100Türkiye Department of Radiology University of ChicagoChicagoIL 60637United States

BAcKGROUND The February 6,2023,twin earthquakes in Türkiye caused significant structural damage and a high number of injuries,particularly affecting the spine,which underscores the importance of understanding the distribution and nature of vertebral injuries in disaster *** To investigate the distribution of radiological findings of vertebral injuries in patients referred to a major tertiary center during the February 6,2023 twin earthquakes in Tü*** With the approval of the institutional ethics committee,1216 examinations of 238 patients transferred from the region to a tertiary major hospital after the twin earthquakes of February 6,2023,were retrospectively analyzed for spine *** Spine computed tomography(cT)scans were performed in 192 of 238 patients with a suspected spinal injury,42 of whom also had an magnetic resonance imaging(MRI).In 86 of 192 patients(44.79%;M:F=33:53)a spinal fracture was detected on cT and in 33 of 42 patients(78.57%;M:F=20:13)a spinal injury was found on *** the 86 patients in whom vertebral injury was detected,fractures were detected in the Denis-B group in 33,Denis-c in 4,Denis-D in 20 and Denis-E in 11 *** the vertebral bodies:40"compression fractures",17"burst fractures",5"translational dislocation fractures",5"flexion-distraction fractures"and 58"prolonged forced fetal posture fractures"were *** addition,isolated transverse or spinous process fractures were found in eighteen *** Our study highlights the prevalence and diverse spectrum of spinal injuries following the February 6,2023 twin earthquakes in Turkey underscoring the urgent need for effective management strategies in similar disaster scenarios,and emphasizing the"prolonged forced fetal posture"damage we encountered in earthquake victims who remained under the collapse for a long time.

关键词： Accidental injuries compression fractures crush injuries Earthquakes Spine

An adaptive range-query optimization technique with distributed replicas

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Journal of central South University 2014年第1期21卷 190-198页

作者： Sayar ahmet Pierce Marlon Fox c.Geoffrey Department of computer Engineering Kocaeli University Department of computer Science Indiana University community Grids Lab Indiana University School of Informatics and computing Indiana University

Replication is an approach often used to speed up the execution of queries submitted to a large dataset.A compile-time/run-time approach is presented for minimizing the response time of 2-dimensional range when a distributed replica of a dataset *** aim is to partition the query payload(and its range) into subsets and distribute those to the replica nodes in a way that minimizes a client's response ***,since query size and distribution characteristics of data(data dense/sparse regions) in varying ranges are not known a priori,performing efficient load balancing and parallel processing over the unpredictable workload is difficult.A technique based on the creation and manipulation of dynamic spatial indexes for query payload estimation in distributed queries was *** effectiveness of this technique was demonstrated on queries for analysis of archived earthquake-generated seismic data records.

关键词： distributed systems load balancing range query query optimization

New Apsidal Motion in Four Eccentric Eclipsing Binaries:V610 car,V944 cep,V2815 Ori and V1260 Tau

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Research in Astronomy and Astrophysics 2022年第11期22卷 69-77页

作者： ahmet Bulut Department of Physics Faculty of Arts and SciencesCanakkale Onsekiz Mart UniversityTerzioglu CampusTR-17020CanakkaleTurkiye Astrophysics Research centre and Observatory Canakkale Onsekiz Mart UniversityTerzioglu CampusTR-17020CanakkaleTurkiye

This paper presents an apsidal motion *** apsidal motion analysis of the eccentric eclipsing binaries V610 car(P=4.84 days),V944 cep(P=6.56 days),V2815 Ori(P=2.13 days),and V1260 Tau(P=5.43 days)was performed using minima times from the O-c Gateway database,ASAS-3,ASAS-SN,and TESS,following Lacy’s *** rates of change of periastron longitude were found to be 0.0253±0.0041,0.0347±0.0015,0.0288±0.0010 and0.0294±0°.0079 cycle^(-1),*** the light curve study,the first photometric mass ratio of V944 cep was found to be q=1.4994±0.0012.A new light curve of V944 cep was obtained using TESS *** first absolute dimensions of V944 cep were M_(1)=1.10±0.01 M_(⊙),M_(2)=1.64±0.02 M_(⊙),R_(1)=2.04±0.37 R_(⊙),R_(2)=3.77±0.67 R_(⊙)for the hotter primary component(T_(1)=4925 K),and M_(1)=1.04±0.01 M_(⊙),M_(2)=1.57±0.02 M_(⊙),R_(1)=2.26±0.36 R_(⊙),R_(2)=3.74±0.59 R_(⊙)for the cooler primary component(T_(1)=4475 K).For V610 car,V944 cep,V2815 Ori and V1260 Tau,the apsidal motion periods were found to be 188±26 yr,186±8 yr,73±3 yr and 182±38 yr,*** V944 cep,the internal structural constants of the component stars log_(k2,obs)=-2.05±0.01 and log_(k2,theo)=-1.83 for hotter primary component and log_(k2,obs)=-1.97±0.01 and log_(k2,theo)=-1.89 for cooler primary component were calculated.

关键词： (stars:)binaries:eclipsing stars:fundamental parameters techniques:photometric

Orientation in Nematic Liquid crystals Doped with Orange Dyes and Effect of carbon Nanoparticles

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chinese Journal of chemical Physics 2010年第3期23卷 368-372,I0002页

作者： ahmet Alicilar Fatih Akkurt Nihan Kaya 加辛大学工学院化学工程系马尔泰佩安卡拉06570

Some properties of nematic liquid crystal E7 doped with two disperse orange dyes used together and effect of addition of carbon nanoparticles （single walled carbon nanotube or fullerene c60） on them were studied. Two dyes （disperse orange 11 and 13） having high solubility and order parameter were used as co-dopants. A notable increase in order parameter was obtained comparing to that of liquid crystal doped with single dye. When carbon nanoparticles were used as dopant, a decrease in order parameter was observed at low temperatures while it increased at high temperatures. When applied voltage changed, the order parameter abruptly increased in its threshold value and saturated in higher voltages as expected. An appreciable change in textures was not observed with addition of dopants. This addition gave rise to an increase in nematic-isotropic phase transition temperatures compared with that of pure liquid crystal.

关键词： Liquid crystal Disperse orange dye carbon nanoparticle Order parameter