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Item Octreotide in combination with AT-101 induces cytotoxicity and apoptosis through up-regulation of somatostatin receptors 2 and 5 in DU-145 prostate cancer cells(Springer Science and Business Media B.V., 2016) Degirmenci M.; Erdogan A.P.; Bulut G.; Atmaca H.; Uzunoglu S.; Karaca B.; Karabulut B.; Uslu R.Prostate cancer (PCa) is the most common type of cancer among males. Although survival rate of early-stage PCa is high, treatment options are very limited for recurrent disease. In this study, the possible synergistic cytotoxic and apoptotic effect of octreotide in combination with AT-101 was investigated in DU-145 hormone and drug refractory prostate cancer cell line. To enlighten the action mechanisms of the combination treatment, expression levels of somatostatin receptors 2 and 5 (SSTR2 and SSTR5) were also investigated. Cell viability was measured by XTT assay. Apoptosis was assessed through DNA fragmentation analysis and caspase 3/7 assay. mRNA and protein levels of SSTR2 and SSTR5 were evaluated by qRT-PCR and western blot analysis, respectively. Octreotide in combination with AT-101 inhibited cell viability and induced apoptosis synergistically in DU-145 cells as compared to any agent alone. Combination treatment increased both SSTR2 and SSTR5 mRNA and protein levels in DU-145 cells. The data suggest that this combination therapy may be a good candidate for patients with advanced metastatic PCa do not respond to androgen deprivation. © 2015, International Society of Oncology and BioMarkers (ISOBM).Item Evaluation of prognostic factors in localized high-grade undifferentiated pleomorphic sarcoma: report of a multi-institutional experience of Anatolian Society of Medical Oncology(Springer Science and Business Media B.V., 2016) Ozcelik M.; Seker M.; Eraslan E.; Koca S.; Yazilitas D.; Ercelep O.; Ozaslan E.; Kaya S.; Hacibekiroglu I.; Menekse S.; Aksoy A.; Taskoylu B.Y.; Varol U.; Arpaci E.; Ciltas A.; Oksuzoglu B.; Zengin N.; Gumus M.; Aliustaoglu M.Most data on prognostic factors for patients with high-grade undifferentiated pleomorphic sarcoma (HGUPS) is obtained from analyses of soft tissue sarcomas. The purpose of this study was to evaluate the clinicopathologic features and their impact on outcomes specifically in patients diagnosed with HGUPS. In this multicenter trial, we retrospectively analyzed 112 patients who were diagnosed and treated at 12 different institutions in Turkey. We collected data concerning the patients, tumor characteristics, and treatment modalities. There were 69 males (61.6 %) and 43 females (38.4 %). Median age was 56 years (19–90). The most common anatomic site of tumor origin was the upper extremity. Pleomorphic variant was the predominant histological subtype. Median tumor size was 8.2 cm (0.6–30 cm). Tumors were mainly deeply seated (57.1 %). Fifty-seven patients (50.9 %) were stage II and the remainder were stage III at the time of diagnosis. Median follow-up was 30 months (2–160). The primary site of distant metastasis was the lung (73.5 %) and the second most common site was the liver (11.7 %). The 5-year overall survival, distant metastasis-free survival, and local recurrence-free survival rates were 56.3, 53.4, and 67.2 %, respectively. Multivariate analysis showed that Eastern Cooperative Oncology Group (ECOG) performance score of II (p = 0.033), deep tumor location (p = 0.000), and development of distant metastasis (p = 0.004) were negatively correlated with overall survival, and perioperative radiotherapy and negative microscopic margins were significant factors for local control rates (p = 0.000 for each). Deep tumor location (p = 0.003) was the only adverse factor related to distant metastasis-free survival. Deep tumor location, ECOG performance score of II, and development of distant metastasis carry a poor prognostic implication on overall survival. These will aid clinicians in predicting survival and treatment decision. © 2015, International Society of Oncology and BioMarkers (ISOBM).Item Combination of zoledronic acid and serine/threonine phosphatase inhibitors induces synergistic cytotoxicity and apoptosis in human breast cancer cells via inhibition of PI3K/Akt pathway(Springer Science and Business Media B.V., 2016) Surmeli Z.; Gursoy P.; Erdogan A.P.; Bozkurt E.; Atmaca H.; Uzunoglu S.; Sezgin C.; Şanlı U.A.; Uslu R.; Karaca B.The aim of this study was to investigate the cytotoxic and apoptotic effects of zoledronic acid (ZA) in combination with serine/threonine protein phosphatase inhibitors, calyculin-A (CA) and okadaic acid (OA), in human MCF-7 and MDA-MB-231 breast cancer cells. XTT cell viability assay was used to evaluate cytotoxicity. DNA fragmentation and caspase-3/7 activity assays were performed to evaluate apoptosis. Activities of phosphatase 1 (PP1) and phosphatase 2A (PP2A) were measured by serine/threonine phosphatase ELISA kit. Expression levels of PI3K, p-PI3K, Akt, p-Akt, Bcl-2, p-Bcl-2, Bad, and p-Bad proteins were evaluated by Western blot analysis. Combination of ZA with either CA or OA showed synergistic cytotoxicity and apoptosis as compared to any agent alone in both MCF-7 and MDA-MB-231 breast cancer cells. Combination treatment also resulted in inhibition of both PP1 and PP2A activities. Both agents used alone or in combination did not induce significant changes in total PI3K, Akt, Bcl-2, and Bad expressions, while p-PI3K, p-Akt, p-Bcl-2, and p-Bad levels were reduced by the combination treatment as compared to agents alone. Moreover, apoptotic effect of combination treatment was significantly inhibited in the presence of LY294002, a specific PI3K inhibitor, in both breast cancer cell lines. In conclusion, synergistic apoptotic effect of the combination treatment is correlated with the block of the PI3K/Akt signal pathway in breast cancer cells. © 2015, International Society of Oncology and BioMarkers (ISOBM).Item The potential role of the NEK6, AURKA, AURKB, and PAK1 genes in adenomatous colorectal polyps and colorectal adenocarcinoma(Springer Science and Business Media B.V., 2016) Kasap E.; Gerceker E.; Boyacıoglu S.Ö.; Yuceyar H.; Yıldırm H.; Ayhan S.; Korkmaz M.Colorectal adenomatous polyp (CRAP) is a major risk factor for the development of sporadic colorectal cancer (CRC). Histone modifications are one of the epigenetic mechanisms that may have key roles in the carcinogenesis of CRC. The objective of the present study is to investigate the alternations in the defined histone modification gene expression profiles in patients with CRAP and CRC. Histone modification enzyme key gene expressions of the CRC, CRAP, and control groups were evaluated and compared using the reverse transcription PCR (RT-PCR) array method. Gene expression analysis was performed in the CRAP group after dividing the patients into subgroups according to the polyp diameter, pathological results, and morphological parameters which are risk factors for developing CRC in patients with CRAP. PAK1, NEK6, AURKA, AURKB, HDAC1, and HDAC7 were significantly more overexpressed in CRC subjects compared to the controls (p < 0.05). PAK1, NEK6, AURKA, AURKB, and HDAC1 were significantly more overexpressed in the CRAP group compared to the controls (p < 0.005). There were no significant differences between the CRAP and CRC groups with regards to PAK1, NEK6, AURKA, or AURKB gene overexpression. PAK1, NEK6, AURKA, and AURKB were significantly in correlation with the polyp diameter as they were more overexpressed in polyps with larger diameters. In conclusion, overexpressions of NEK6, AURKA, AURKB, and PAK1 genes can be used as predictive markers to decide the colonoscopic surveillance intervals after the polypectomy procedure especially in polyps with larger diameters. © 2015, International Society of Oncology and BioMarkers (ISOBM).Item Apoptotic and anti-angiogenic effects of Salvia triloba extract in prostate cancer cell lines(Springer Science and Business Media B.V., 2016) Atmaca H.; Bozkurt E.Plants, due to their remarkable composition, are considered as natural resources of bioactive compounds with specific biological activities. Salvia genus (Lamiaceae) has been used around the world in complementary medicine since ancient times. We investigated the cytotoxic, apoptotic and anti-angiogenic effects of methanolic Salvia triloba extract (STE) in prostate cancer cells. Cell viability was evaluated by XTT; apoptosis was investigated by DNA fragmentation and caspase 3/7 activity assays. Changes in the angiogenic cytokine levels were investigated by human angiogenesis antibody array. Scratch assay was used to determine the cell motility. STE induced cytotoxicity and apoptosis in a concentration-dependent manner in both cancer cells; however, it was not cytotoxic to normal cells. Cell motility was reduced in PC-3, DU-145 and HUVEC cells by STE treatment. ANG, ENA-78, bFGF, EGF, IGF-1 and VEGF-D levels were significantly decreased by −2.9, −3.7, −1.7, −1.7, −2.0 and −1.8 fold in STE-treated DU-145 cells, however, ANG, IL-8, LEP, RANTES, TIMP-1, TIMP-2 and VEGF levels were significantly decreased by −5.1, −2.0, −2.4, −3.1, −1.5, −2.0 and −2.5 fold in PC-3 cells. These data suggest that STE might be a promising candidate for anti-tumor and anti-angiogenic treatment of prostate cancer. © 2015, International Society of Oncology and BioMarkers (ISOBM).Item Fuzzy conceptual hydrological model for water flow prediction(Springer Science and Business Media B.V., 2016) Turan M.E.; Yurdusev M.A.Reliability in flow prediction is key to designing water resources projects. Over prediction may result in overdesign whereas under prediction brings about insufficient capacity solutions. While the former means insufficient use of financial resources, the latter may result in some water demand unmet. Therefore, so many techniques have been developed and used to make better flow prediction. In this study, this traditional problem is revisited in an attempt to improve the modeling performance of long used conceptual hydrological models. This is attained by incorporating fuzzy systems into a presently used conceptual model. The fuzzy integration process is carried out through the replacement of the storage elements of conceptual model by fuzzy systems. The case study undertaken has proved that the fuzzy conceptual model developed is quite competitive with ordinary conceptual model and promises improved predictions. © Springer Science+Business Media Dordrecht 2015.Item Thermal characterization of chicken feather/PLA biocomposites(Springer Science and Business Media B.V., 2017) Özmen U.; Baba B.O.In this work, thermal properties of composites from chicken feather fiber (CFF) and polylactic acid (PLA) were investigated. CFF/PLA green composites were manufactured by extrusion and injection molding. Short and long fibers (3 and 20 mm) were used at different contents (2, 5 and 10 mass%). The effects of fiber concentration and fiber length on thermal properties of CFF/PLA composites were studied. Thermal properties of CFF/PLA composites were examined through differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and dynamic mechanical analysis (DMA). From the experiments, it was found that addition of CFF was effective to improve the thermal properties of PLA. The DSC results showed that heat flow increased with the increase in CFF content on the glass transition, on the crystallization temperature and on melting temperature. The TG results revealed that addition of CFF to PLA had positive effect on the thermal stability. In addition, the results of DMA experiments showed that the tan δ decreased with the increasing CFF content, indicating less damping and more elastic behavior in the composites. The results obtained from this study provide important information on the temperature-dependent properties of CFF/PLA and lead to new product development based on natural resources. © 2017, Akadémiai Kiadó, Budapest, Hungary.Item Application of inductive forced heating as a new approach to food industry heat exchangers: A case study—Tomato paste pasteurization(Springer Science and Business Media B.V., 2018) Başaran A.; Yılmaz T.; Çivi C.Heat exchangers are one of the main equipment used in food industry because of their convenience to transfer energy to both auxiliary facilities and various food products. In food industry, there are several reasons for heat transfer such as pre-heating, pasteurizing and sterilizing in which heat exchangers require high amount of energy. On the other hand, as being a unique quality assurance unit heat exchangers should be cleaned easily and extensively. Having high operating costs due to energy consumption and requiring high investment cost due to ensure a reliable hygienic design make heat transfer units an expensive and energy-consuming unit. Therefore, developing new approaches to generate energy and transferring it hygienically with minimum loses will be an opportunity for the food industry. With the view of developing new equipment for industry, induction-driven heating system was investigated in this study and energy and exergy efficiencies were calculated and compared with conventional heat exchanger system. Selected food system was the tomato paste sterilization/pasteurization which is a part of tomato paste production line. After assumptions and theoretical calculations for both conventional application and inductive heating, it was found that inductive heating system has 95.00% energy efficiency and 46.56% second law efficiency while the conventional heating system with electric boiler has 75.43% energy efficiency and 16.63% exergy efficiency. As a consequence, inductive method was found more beneficial compared to a commercial method having higher energy and exergy efficiencies. © 2018, Akadémiai Kiadó, Budapest, Hungary.Item Predicting career adaptability through self-esteem and social support: A research on young adults(Springer Science and Business Media B.V., 2018) Ataç L.O.; Dirik D.; Tetik H.T.The purpose of this study is to investigate the relationship between career adaptability and self-esteem, and analyze the moderating role of social support in this relationship on a sample of 313 young adults. The results of the study confirm that career adaptability is significantly predicted by self-esteem. Moreover, findings suggest that (1) self-esteem enhances career adaptability, (2) perceived social support positively predicts career adaptability, and (3) perceived social support plays a moderating role in the relationship between perceptions of self-esteem and career adaptability sub-scales. Self-esteem and social support positively predict young adults’ career adaptability above and beyond the effects of demographics. © 2017, Springer Science+Business Media Dordrecht.Item Natural convection in a CuO–water nanofluid filled cavity under the effect of an inclined magnetic field and phase change material (PCM) attached to its vertical wall(Springer Science and Business Media B.V., 2019) Selimefendigil F.; Oztop H.F.; Chamkha A.J.In this study, natural convection of CuO–water nanofluid in a square cavity with a conductive partition and a phase change material (PCM) attached to its vertical wall is numerically analyzed under the effect of an uniform inclined magnetic field by using finite element method. Effects of various pertinent parameters such as Rayleigh number (between 10 5 and 10 6), Hartmann number (between 0 and 100), magnetic inclination angle (between 0 ∘ and 90 ∘), PCM height (between 0.2H and 0.8H), PCM length (between 0.1H and 0.8H), thermal conductivity ratio (between 0.1 and 100) and solid nanoparticle volume fraction (between 0 and 0.04) on the fluid flow and thermal characteristics were numerically analyzed. It was observed that when magnetic field is imposed, more reduction in average Nusselt number for water is obtained as compared to nanofluid which is 31.81 % for the nanofluid at the highest particle volume fraction. The average heat transfer augments with magnetic inclination angle, but it is less than 5 %. When the height of the PCM is increased which is from 0.2H to 0.8H, local and average Nusselt number reduced which is 42.14 % . However, the length of the PCM is not significant on the heat transfer enhancement. When the conductivity ratio of the PCM to the base fluid within the cavity is increased from 0.1 to 10, 29.5 % of the average Nusselt number enhancement is achieved. © 2018, Akadémiai Kiadó, Budapest, Hungary.Item Magnetohydrodynamics mixed convection in a power law nanofluid-filled triangular cavity with an opening using Tiwari and Das’ nanofluid model(Springer Science and Business Media B.V., 2019) Selimefendigil F.; Chamkha A.J.Numerical simulation of mixed convection heat transfer in a lid-driven triangular cavity filled with power law nanofluid and with an opening was performed under the effect of an inclined magnetic field. The left vertical wall of the cavity moves in + y-direction, and the bottom wall of the cavity is partially heated. Galerkin weighted residual finite element method was used to solve the governing equations. Influence of Richardson number, Hartmann number, inclination angle, opening ratio and nanoparticle volume fraction on the fluid flow and heat transfer is examined for various power law indices. It was observed that average heat transfer deteriorates as the value of Richardson number and Hartmann number enhances. At the lowest value of Richardson number, the discrepancy between the average heat transfer corresponding to different power law indices is higher. The inclination angle of the magnetic field where the minimum of the average Nusselt number is seen depends on the fluid type. Average heat transfer number is the highest for the highest value of the opening ratio. The average Nusselt number enhances with solid particle volume fraction, and there are slight variations in the reduction in the average Nusselt number when base fluid and nanofluid are considered for various power law indices. © 2018, Akadémiai Kiadó, Budapest, Hungary.Item MHD mixed convection in a nanofluid filled vertical lid-driven cavity having a flexible fin attached to its upper wall(Springer Science and Business Media B.V., 2019) Selimefendigil F.; Oztop H.F.; Chamkha A.J.In this study, fluid flow and heat transfer in a vertical lid-driven CuO–water nanofluid filled square cavity with a flexible fin attached to its upper wall under the influence of an inclined magnetic field are numerically investigated. The left vertical wall of the cavity is colder than right vertical wall, and it moves in + y direction with constant speed. Horizontal walls of the cavity are insulated. The governing equations are solved with finite element method. The arbitrary Lagrangian–Eulerian method is used to describe the fluid motion within the cavity for the flexible fin in the fluid-structure interaction model. The influence of Richardson number (between 0.01 and 100), Hartmann number (between 0 and 50), inclination angle of the magnetic field (between 0 and 90%), nanoparticle volume fraction (between 0 and 0.05) and Young’s modulus of flexible fin (between 250 and 5000) on the flow and heat transfer were numerically studied. It is observed that the presence of the elastic fin affects the flow field and thermal characteristics of the cavity. The local and average heat transfer enhance as the Richardson number, solid volume fraction of the nanoparticle increase whereas deteriorate as the value of the Hartmann number and inclination angle of the magnetic field increases due to the dampening of the fluid motion with Lorentz forces. The addition of the nanoparticles is more effective along the lower part of the right vertical wall where the heat transfer process is effective. The average heat transfer increases by 28.96% for solid volume fraction of 0.05% compared to base fluid when the flexible fin is attached to the upper wall. The average heat transfer deteriorates by 10.10% for cavity with and without fin at Hartmann number of 50 compared to the case without magnetic field. The average heat transfer enhances as the Young’s modulus of the flexible fin decreases and the average Nusselt number increases by 13.24% for Young’s modulus of 250 compared to configuration for the cavity having the Young’s modulus of 5000. © 2018, Akadémiai Kiadó, Budapest, Hungary.Item Analysis of mixed convection and entropy generation of nanofluid filled triangular enclosure with a flexible sidewall under the influence of a rotating cylinder(Springer Science and Business Media B.V., 2019) Selimefendigil F.; Oztop H.F.; Chamkha A.J.In this study, mixed convection and entropy generation in a nanofluid filled triangular cavity under the influence of rotating cylinder and flexible sidewall were numerically analyzed with finite element method. The inclined sidewall was cooled while the left vertical wall is partially heated. Heat transfer rate enhances as the values of Rayleigh number, angular rotational velocity of the cylinder, elastic modulus of the flexible sidewall and solid nanoparticles volume fraction increase. Nusselt number enhances more in the counter-clockwise direction of the cylinder as compared to clockwise directional rotation and 13.55% of average heat transfer enhancement was achieved for Ω= 3000 when compared to motionless cylinder. Average Nusselt number increases by about 30.50% when the elastic modulus of the flexible wall is changed from 500 to 10 5. The changes in the velocity profiles are significant for the lower part of the triangular enclosure with respect to changes in angular rotational velocity and elastic modulus as compared to upper part of the cavity. Adding nanoparticles increases heat transfer especially for the lower part of the cavity and 49.63% of heat transfer enhancement was achieved for the highest volume fraction when compared to base fluid. Normalized total entropy generation rates enhance for higher values of elastic modulus of the flexible wall, angular rotational speed of the circular cylinder and nanoparticle volume fractions. © 2018, Akadémiai Kiadó, Budapest, Hungary.Item Mixed convection due to a rotating cylinder in a 3D corrugated cavity filled with single walled CNT-water nanofluid(Springer Science and Business Media B.V., 2019) Selimefendigil F.; Oztop H.F.; Abu-Hamdeh N.H.Analysis of mixed convection due to a rotating inner cylinder in a corrugated three-dimensional cavity filled with carbon nanotube-water nanofluid was performed. Numerical simulations were performed by using Galerkin weighted residual finite element method. The three-dimensional corrugated cavity was differentially heated form the vertical surfaces, and an inner rotating adiabatic cylinder was used. Influence of Rayleigh number (between 104 and 106), angular rotational velocity of the cylinder (between − 50 and 50 rad/s), height (between H / 10 and H / 3) and number of triangular waves (between 1 and 16) and solid nanoparticle volume fraction (between 0 and 0.04) on the convective heat transfer characteristics was analyzed. It was observed that average heat transfer augments significantly by changing the nanoparticle volume fraction and up to 128% of enhancement is obtained. Depending on the rotational direction of the cylinder, average Nusselt number enhances 68 % in the three-dimensional cavity. Surface corrugation parameters are not as effective as solid particle volume fraction and angular rotational speed of the cylinder on the heat transfer enhancements. Finally, a correlation for the average Nusselt number along the cold surface was provided which is dependent upon the angular rotational speed of the cylinder and Rayleigh number. © 2018, Akadémiai Kiadó, Budapest, Hungary.Item Effects of a partially conductive partition in MHD conjugate convection and entropy generation for a horizontal annulus(Springer Science and Business Media B.V., 2020) Selimefendigil F.; Oztop H.F.; Mahian O.Magnetohydrodynamic free convection in a horizontal annulus formed by two isothermal surfaces and partially partitioned with a conductive ring was numerically studied by using finite element method. The numerical investigation was performed for various values of Rayleigh numbers (between 104 and 106), Hartmann number (between 0 and 40), magnetic inclination angle (between 0° and 90°), thermal conductivity ratio (between 0.01 and 100) and various locations of the conductive partition. Average Nusselt number enhances as the value of Rayleigh number, magnetic inclination angle and thermal conductivity ratio increases and as the value of Hartmann number decreases. The location of the partial conductive partition on the average Nusselt number becomes more effective for higher values of Rayleigh number and lower values of Hartmann number. Heat transfer process is effective when the partition is located on the bottom part of the hot wall. Heat transfer enhancement with location of the partition depends on the inclination angle of the magnetic field. Second law analysis of the system with entropy generation was also performed. It was observed that for higher values of magnetic field strength and lower values of magnetic inclination angle the entropy generation rate reduces, while the conductivity ratio increases the entropy generation rate. © 2019, Akadémiai Kiadó, Budapest, Hungary.Item MHD conjugate natural convection in a porous cavity involving a curved conductive partition and estimations by using Long Short-Term Memory Networks(Springer Science and Business Media B.V., 2020) Selimefendigil F.; Akbulut Y.; Sengur A.; Oztop H.F.In this study, MHD conjugate free convection of a porous cavity having a curved shape conductive partition is numerically analyzed by using the Galerkin weighted residual finite element method. The numerical simulation is performed for different values of pertinent parameters: Rayleigh number (between 10 4 and 10 6), Hartmann number (between 0 and 60), Darcy number (between 5 × 10 - 4 and 0.05), porosity of the medium (between 0.25 and 0.75), curvature of the partition (minor axis radius of the horizontal ellipse, between 0.01H and 0.3H) and conductivity ratio (between 0.05 and 50). It was observed that the heat transfer rate enhances locally and in average for higher values of Rayleigh number, Darcy number, porosity of the medium and conductivity ratio, whereas the impact is opposite for higher values of Hartmann number. The amount of average Nusselt number reduction is obtained as 22 % when Hartmann number is changed from 0 to 60 at Rayleigh number of 10 5. Curvature and conductivity of the curved partition affect the variation in fluid flow and heat transfer characteristics. Maximum of 7 % variation in the average Nusselt number is achieved when the curvature of the conductive partition is varied but the effects of thermal conductivity ratio on heat transfer rate are higher. Long Short-Term Memory Networks are used for estimation of the velocity and temperatures in the computational domain for various values of pertinent input parameters variation in the system which includes conjugate heat transfer mechanism in a porous enclosure with complex-shaped conductive partition under the effects of magnetic field. © 2019, Akadémiai Kiadó, Budapest, Hungary.Item Impacts of conductive inner L-shaped obstacle and elastic bottom wall on MHD forced convection of a nanofluid in vented cavity(Springer Science and Business Media B.V., 2020) Selimefendigil F.; Öztop H.F.; Abu-Hamdeh N.Forced convection of nanofluid in a vented cavity with elastic bottom wall is studied by using an inner conductive L-shaped object and magnetic field. Simulations are performed using the finite element method when the impacts of various pertinent parameters, such as Reynolds number (between 100 and 500), Hartmann number (between 0 and 40), elastic modulus of the flexible wall (between 10 5 and 10 9), solid nanoparticle volume fraction (between 0 and 0.04), size (between 0.1 and 0.4H), inclination (between − 90 and 90) and location (xc between 0.25 and 0.75 H and yc between 0.15 and 0.65H) of the L-shaped object on the fluid flow and heat transfer features, are investigated. It was observed that wall flexibility effects are influential for the configuration with strong convection and maximum of 11 % enhancement in the average heat transfer rate for the bottom wall is achieved. Suppression of the recirculations in the vented cavity and around the L-shaped object is observed with magnetic field. It is observed that impact of magnetic field on heat transfer enhancement is different for different segments of hot wall. When the cases with the highest magnetic field and in the absence of magnetic field are compared, the average heat transfer enhancement of 5.5 % is achieved for bottom elastic wall while 24.5 % of reduction in the average heat transfer is seen for upper hot wall. The overall Nusselt number reduces slightly when the magnetic field strength is increased. Significant impacts of the size, inclination and location of the of the L-shaped conductive object on the fluid flow such as branching of the main flow stream, size of the vortex below the inlet port and heat transfer are observed. 31.6 % rise of the average heat transfer for left vertical wall and 34.6 % reduction of average heat transfer for bottom wall are achieved when the minimum and maximum of the orientation angles are compared. The location of the L-shaped object has a significant impact on the flow and thermal pattern variations. The highest variation in the contribution to the overall heat transfer is seen for right vertical hot wall segment when the Nusselt numbers at the lowest and highest values of the horizontal and vertical locations of the object are compared. L-shaped object was found to be an efficient tool to control the heat transfer features of the vented cavity. Nanofluid inclusion resulted in heat transfer enhancement in the range of 8.5–16.5% while amount of enhancement is different for different hot wall segments either in the absence or in the presence of magnetic field effects. Finally, a polynomial-type correlation for the average Nusselt number of each hot wall segments of the vented cavity is proposed for water and for nanofluid at ϕ= 0.04. © 2019, Akadémiai Kiadó, Budapest, Hungary.Item Evaluation of effects of positive airway pressure treatment on retinal fiber thickness and visual pathways using optic coherence tomography and visual evoked potentials in the patients with severe obstructive sleep apnea syndrome(Springer Science and Business Media B.V., 2020) Batum M.; Kısabay A.; Mayalı H.; Göktalay T.; Kurt E.; Selçuki D.; Yılmaz H.Introduction: Hypoxia during sleep in obstructive sleep apnea syndrome (OSAS) increases intracranial pressure, decreases cerebral perfusion pressure, and alters vascular supply to the optic nerve. Pattern visual evoked potential (pVEP) has revealed that it causes alterations in the optic nerve, and optic coherence tomography has shown that it causes alterations in the retinal and macular layers. Objectives: To detect and compare possible alterations in macula and peripapillary retinal nerve fiber thickness (pRNFL) using OCT and in the optic nerve pathways using pVEP before and after positive airway pressure (PAP) in the patients with severe OSAS. Materials and methods: Thirty patients who were diagnosed as having severe OSAS in the neurology-sleep outpatient clinic and 30 healthy control subjects were included in the study. Ophthalmic examinations were performed prior to (month 0) and after (month 6) PAP treatment, and pVEP (peak time [PT] and amplitude) and OCT parameters (peripapillary retinal-macular layers) were compared. Results: In the comparison between the severe OSAS (before treatment) and control groups, thinning was found in pRNFL (average, nasal, inferior) and in the macular layers (external and internal superior quadrants) (p < 0.05). pVEP investigation revealed increased PT in P100 and N145 waves and decreased amplitude of N75–P100 waves. In the comparisons before and after PAP treatment, a decrease in PT of N75 and P100 waves and increase in N75–P100 amplitudes were found. In the pRNFL, significant thickening was found in the layers with thinning before treatment, whereas no significant thickening was found in macular layers, except for the fovea. Discussion: It was shown that PAP treatment in patients with severe OSAS prevents hypoxia without causing alterations in intraocular pressure and thus reduces inflammation and causes thickening in the pRNFL and macular layers. © 2020, Springer Nature B.V.Item Convective drying of a moist porous object under the effects of a rotating cylinder in a channel(Springer Science and Business Media B.V., 2020) Selimefendigil F.; Özcan Çoban S.; Öztop H.F.Numerical study of evaporation in porous medium during convective drying process was examined, and heat and mass transfer of liquid water and water vapor through porous media was investigated by using the Galerkin weighted residual finite element method. The porous moist object has a rectangular shape and is assumed to represent a food sample. Two-dimensional laminar flow of dry hot air was used in the channel with a rotating circular cylinder. Different locations and angular rotational speed of the rotating cylinder were considered to control the convective heat transfer and mass transportation. The radius of rotating cylinder and velocity of drying air were also varied with five different values. Results showed that rotational angular speed and drying air velocity had significant effect on heat transfer and mass transport phenomenon for the porous moist object. © 2019, Akadémiai Kiadó, Budapest, Hungary.Item Nanojet impingement cooling of an isothermal surface in a partially porous medium under the impact of an inclined magnetic field(Springer Science and Business Media B.V., 2020) Selimefendigil F.; Öztop H.F.In this study, jet impingement heat transfer characteristics for a layered nanofluid and porous domains under the effects of inclined uniform magnetic field are examined by using Galerkin weighted residual finite element method. Effects of various pertinent parameters such as Reynolds number (between 100 and 500), Hartmann number (between 0 and 6), magnetic inclination angle (between 0 and 90), Darcy number (between 10 - 4 and 10 - 2) and height of porous layer (between 0.25 H and 4 H) on the fluid flow and heat transfer are analyzed. It was observed that local and average heat transfer rate enhance when the value of Reynolds number, magnetic field inclination angle and permeability of the porous layer increase, while the impact is reversed for magnetic field strength. Magnetic field inclination angle has more influence on the convective heat transfer features as compared to strength, and for a horizontally aligned magnetic field heat transfer process is inefficient. When cases in the absence and presence of magnetic field (at Hartmann number of 6) are compared, 28 % of reduction in the average heat transfer is obtained. An optimum value of porous layer height is observed where the highest heat transfer rates are achieved. © 2019, Akadémiai Kiadó, Budapest, Hungary.