Browsing by Author "Sahin, S"

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    Psychometric Properties of the Turkish Version of the University o Virginia Parent Low Blood Sugar Survey
    Sen Celasin, N; Özcelik, ÇÇ; Sahin, S
    Objective: The aim of this study was to produce and validate a Turkish version of the University of Virginia Parent Low Blood Sugar Survey (P-LBSS). The P-LBSS is used to assess parental fear of their diabetic children's hypoglycemia. Methods: Linguistic, content and face validity of the translated P-LBSS was tested. Afterwards, explanatory and confirmatory factor analyses were conducted in order to evaluate construct validity. Results: The sample included 390 parents of type 1 diabetic adolescents aged 12-17 years. Results of the factor analysis showed that the Turkish P-LBSS had 2 subscales (behavior and worry) as in the original. The Cronbach's alpha coefficient of the Turkish version of the total P-LBSS was found to be 0.803, and the value was 0.865 for the behavior and 0.790 for the worry subscales. Psychometric investigation of the Turkish version of P-LBSS indicated high reliability and good retestability, content and construct validity. Conclusion: The Turkish P-LBSS is a valid and reliable instrument to measure the fear of hypoglycemia experienced by parents of diabetic adolescents aged between 12-17 years in the TUrkish population.
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    An investigation of the effects of chronic zonisamide, sultiam, lacosamide, clobazam, and rufinamide anti-seizure medications on foliculogenesis in ovarian tissue in prepubertal non-epileptic rats
    Kart, PO; Gürgen, SG; Esenülkü, G; Dilber, B; Yildiz, N; Yazar, U; Sarsmaz, HY; Topsakal, AS; Kamasak, T; Arslan, EA; Sahin, S; Cansu, A
    We aimed to determine the morphological and histological effects of zonisamide, sultiam, lacosamide, clobazam, and rufinamide on ovarian folliculogenesis in rats. Sixty female Wistar rats were divided into six experimental groups as control, zonisamide, sultiam, lacosamide, clobazam, and rufinamide groups; control solution and drugs were administered by gavage for 90 days. The number of healthy follicles in the control group was significantly higher than in the anti-medication groups (p < 0.001), and the number of corpus luteum was significantly lower (p < 0.001). There was a significant difference in the number of TUNEL positive apoptotic follicles between the control and drug groups (p < 0.001). With EGF, IGF-1, and GDF-9 staining, a very strong immunoreaction was observed in the ovarian multilaminar primary follicle granulosa cells and oocytes in the control group compared to the drug group (p < 0.001). Long-term anti-seizure medication with zonisamide, sultiam, lacosamide, clobazam, and rufinamide from prepubertal to adulthood causes apoptosis and disruption of folliculogenesis in the ovarian follicles of nonepileptic rats.
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    Characterization and determination of FexB layers' mechanical properties
    Culha, O; Toparli, M; Sahin, S; Aksoy, T
    The aim of this study is to obtain microstructural characteristics and investigate the mechanical properties such as hardness, Young's modulus and fracture toughness of the boride layer depending on process time and temperature. The produced double layers (FeB and Fe2B) were extensively analyzed with respect to X-ray, diffraction (XRD) and scanning electron microscopy (SEM). The XRD pattern of the boride layers, which were formed on SAE 1020 and 1040 quality steel at 900 degrees C for 2 h, 4 h and 6 h, include only FeB phase on surface with (111), (2 10), (10 1) and (111) planes. SEM cross-sectional investigations show that double-phase boride layer existence from surface to inside of substrate. The structural compositions of layers consist of boron rich phase (FeB) and iron rich phase (Fe2B), respectively. Surface roughness value of samples is important parameter for micro-indentation test with Dynamic Ultra Micro Hardness Tester. After diffusion controlled boriding process, material surface roughness can be high for micro-indentation test. So, surface polishing process is applied for decreasing roughness of FeB layers. Surface roughness values of 2 h, 4 h and 6 b borided SAE 1020 and SAE 1040 quality steel were decreased from 0.9 mu m to 0.05 mu m by polishing process. Mechanical properties of layers were examined by Shimadzu Dynamic Ultra-microhardness test machine for estimating Young's modulus due to load-unload sensing analysis and in addition to mechanical investigation hardness-depth curves of the layer were obtained for estimating indentation depth and load dependency of mechanical properties. Load depended elastic modulus (12S-624 GPa) and hardness (17-33 GPa) were obtained at 80 mN, 160 mN, 320 mN and 640 mN applied peak loads depending on boriding process time. Fracture toughness proper-ties of FeB surface layers were calculated by Vickers Fracture Toughness method for 1 N applied peak load with measuring crack length after loading stage was finished. (c) 2007 Elsevier B.V. All rights reserved.
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    The Curriculum of Social Studies Education and World Citizenship: From Perspective of Prospective Teachers
    Sahin, M; Sahin, S; Gögebakan-Yildiz, D
    The primary purpose of the study is to analyze the relationships between Inclusion of the concept of world citizenship in Social Studies Education Program and Practices (SSEPP) and world citizenship competency perceptions (WCCP) of prospective SSE teachers. This is a relational screening study model. World Citizenship Scale in SSEPP and World Citizenship Competency Perception Scale that were developed by the researchers were used in the study. A total of 375 fourth grade prospective primary education teachers in SSE departments of randomly selected universities to represent seven different geographical regions of Turkey constituted the sampling of the study. The results showed that prospective teachers evaluated SSEPP at moderate level in terms of its dimensions are objects, content, learning situations and evaluation and general of the scale. Likewise, the prospective teachers perceived world citizenship at moderate level. This result points out that even training of world citizen individuals at the SSE program is aimed, this objective couldn't be adequately reflected in selected texts, intra-class activities and evaluation processes. In addition, prospective teachers who graduated from Anatolian high school and their parent graduated from university had higher perception on the world citizenship. Finally, the findings show that there is a positive and weak relationship between SSEPP and WCCP.
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    Residual thermal stress analysis in cylindrical steel bars using finite element method and artificial neural networks
    Toparli, M; Sahin, S; Ozkaya, E; Sasaki, S
    In this study, it was proposed that the residual stresses within steel bars after quenching in water from 600 degreesC could be calculated by using the finite element method (FEM) and an artificial neural network (ANN) algorithm. Three modelled cylindrical specimens of AISI 1020 steel were heated and then quenched in water. Using FEM, temperature distribution with time and thermal residual stress values in the samples were calculated after cooling. The analysis was extended to elastic-plastic deformation during the quenching of steel cylinders of various diameters. The calculated temperature and thermal residual stress values were used in training a multi-layer, feed forward, back propagation ANN algorithm. The results obtained via the ANN algorithm method have been compared with the FEM results. Comparison showed good agreement. (C) 2002 Elsevier Science Ltd. All rights reserved.
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    Hardness profiles of Sn-3.0Ag-0.5Cu-TiO2 composite solder by nanoindentation
    Yahaya, MZ; Ani, FC; Samsudin, Z; Sahin, S; Abdullah, MZ; Mohamad, AA
    Improvement of the hardness values of Sn-3.0Ag-0.5Cu-TiO2 composite solders with different TiO2 weight percentages was evaluated by nanoindentation. The composite solders were prepared by ball milling of Sn-3.0Ag-0.5Cu solder with TiO2 nanoparticles at 300 rpm for 10 min prior to printing and reflowing. Structural analysis indicated that the TiO2 nanoparticles were successfully blended into the Sn-3.0Ag-0.5Cu solder. Finer Cu6Sn5 and Ag3Sn phases were observed in the composite solder micrographs. The optimum hardness of 1.775 GPa was obtained for the composite solders with a TiO2 content of 1 wt%. A further increment of the TiO2 content to 1.5 wt% significantly reduced the hardness value to 1.677 GPa. The hardness profiles were established based on the specific measurement pattern obtained from the nanoindentation. The mechanism of the influence of TiO2 nanoparticles on the refinement of the intermetallic phases and improvement of the hardness value is also presented. (C) 2016 Elsevier B.V. All rights reserved.
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    Vitamin D protects against hippocampal apoptosis related with seizures induced by kainic acid and pentylenetetrazol in rats
    Sahin, S; Gürgen, SG; Yazar, U; Ince, I; Kamasak, T; Arslan, EA; Durgut, BD; Dilber, B; Cansu, A
    Objectives: The hippocampus is susceptible to damage in patients with epilepsy and in animals with seizures caused by excitotoxic agents. The effect of vitamin D on hippocampal apoptosis related with seizures has not been reported. However, epileptic patients have an increased risk of hypovitaminosis D which is most likely due to the effects of antiepileptic drugs. Therefore, in this study, it was aimed to evaluate the effects of vitamin D on hippocampal apoptosis related with seizures by using pentylenetetrazol (PTZ) and kainic acid (KA) in rats. Methods: Male Sprague Dawley rats, aged 5.5 weeks, were randomly divided into six groups: control, vitamin D, PTZ, KA, PTZ + vitamin D and KA + vitamin D groups. The groups that received vitamin D were given 500 IU/kg of vitamin D daily for two weeks in addition to a standard diet. At the end of this period, PTZ and KA were applied to trigger seizures in the rats in the seizure groups. 24 h after the administration of PTZ and KA, the rats were decapitated. In the hippocampal region, apoptosis was assessed by TUNEL and brain-derived neurotrophic factor (BDNF), Bax, caspase-3 and c-fos activation were evaluated by immunohistochemical method. Results: BDNF level increased while c-fos, Bax and caspase-3 levels decreased (p < 0.0001, in all) in the hippocampal neurons of the groups that were pre-treated with vitamin D before the administration of PTZ and KA, in comparison with the PTZ and KA groups. Vitamin D significantly decreased the number of apoptotic cells in these rats in comparison with the PTZ and KA groups (p < 0.0001). Conclusion: This study indicates that vitamin D has neuroprotective effects on hippocampal apoptosis induced by PTZ and KA in rats. With this study it is suggested that keeping vitamin D levels within normal limits may be beneficial for patients with epilepsy, especially children.
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    Heat Treatment Effects on Mechanical Properties of Atmospheric Plasma Sprayed FexB Coatings on Al Substrate
    Culha, O; Sahin, S; Ozdemir, I; Toparli, M
    In this work, we draw attention to determination of heat-treatment effects on mechanical properties of atmospheric plasma sprayed (APS) FexB coatings on aluminum substrates by micro-indentation technique. With this regard, iron boride powders of Fe-18.8B-0.2C-0.5Si-0.8Al (wt.%) were deposited onto Al substrates by APS in order to improve the mechanical properties of Al surface. As-sprayed coatings are composed of mainly FexB and iron matrix supersaturated with boron owing to the rapid solidification of molten droplets flattened on a substrate. It was observed that APS coatings exhibited characteristic wavy layered structure having porosity, inclusions, and semi-melted particles. The postfurnace treatment of APS coatings was carried out at temperatures ranged from 450 to 550 degrees C in an argon atmosphere. The post-treatment applied for APS deposits led to increase in hardness of 40% without showing cracks. Furthermore, micro-mechanical properties of FexB coatings were examined by Shimadzu Dynamic Ultra-Microhardness Tester for estimating Young's modulus and hardness due to load-unload sensing analysis by applying different loads such as 160, 320, and 640 mN to determine load and indentation depth dependency of APS FexB on Al substrate for each samples, in details.
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    THE ATTITUDES OF MEDICAL STUDENTS TOWARD THE ELDERLY
    Elbi, H; Altan, S; Rahman, S; Cengiz Özyurt, B; Sahin, S; Çam, FS
    Introduction: Health workers must be prepared for the changes and developments due to the ever-increasing proportion of elderly individuals within the general population. This study aimed to identify the general attitudes of students of the Faculty of Medicine of Celal Bayar University (CBU) toward senility and evaluate differences in the attitudes of students at different stages of medical education. Materials and Method: This study was conducted between October and December 2014 and included a total of 406 students attending the Faculty of Medicine of the CBU. A questionnaire form composed of three sections was used to collect data. Results: The age range of study participants was 18-27 years (average age, 21.04 years), 60.8% were females, and 91.4% had a nuclear family structure. When assessing overall UCLA scores according to the stage of medical education, the average scores of first-year students were found to be higher than other year groups. The results of the UCLA questionnaire demonstrated significantly higher overall scores concerning attitudes toward older persons in female students compared with male students. No significant differences in KOGAN questionnaire scores concerning attitudes toward older people were observed between male and female students. Conclusion: The findings of the present study indicate that attitudes toward the elderly change negatively as students progress through medical education. In addition, female students had more positive attitudes toward elderly patients than male students. Considering the expectations from the healthcare providers of the elderly population, who are more fragile compared to normal individuals, it should be envisaged that the responsibilities of physicians have increased.
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    Oleuropein Has Modulatory Effects on Systemic Lipopolysaccharide-Induced Neuroinflammation in Male Rats
    Sahin, S; Sahin, E; Esenülkü, G; Renda, G; Gürgen, SG; Alver, A; Abidin, I; Cansu, A
    Background: Neuroin fl ammation induced by systemic in fl ammation is a risk factor for developing chronic neurologic disorders. Oleuropein (OLE) has antioxidant and anti-in fl ammatory properties; however, its effect on systemic in fl ammation-related neuroin fl ammation is unknown. Objectives: This study aimed to determine whether OLE protects against systemic lipopolysaccharide (LPS)-induced neuroin fl ammation in rats. Methods: Six-wk-old Wistar rats were randomly assigned to 1 of the following 5 groups: 1 ) control, 2 ) OLE-only, 3 ) LPS & thorn; vehicle, 4 ) OLE & thorn; LPS (O-LPS), and 5 ) a single-dose OLE & thorn; LPS (SO-LPS group). OLE 200 mg/kg or saline as a vehicle was administered via gavage for 7 d. On the seventh day, 2.5 mg/kg LPS was intraperitoneally administered. The rats were decapitated after 24 h of LPS treatment, and serum collection and tissue dissection were performed. The study assessed astrocyte and microglial activation using glial fi brillary acidic protein (GFAP) and CD11b immunohistochemistry, nod -like receptor protein -3, interleukin (IL)-1 beta , IL -17A, and IL -4 concentrations in prefrontal and hippocampal tissues via enzyme-linked immunosorbent assay, and total antioxidant/oxidant status (TAS/TOS) in serum and tissues via spectrophotometry. Results: In both the O-LPS and SO-LPS groups, LPS-related activation of microglia and astrocytes was suppressed in the cortex and hippocampus ( P < 0.001), excluding cortical astrocyte activation, which was suppressed only in the SO-LPS group ( P < 0.001). Hippocampal GFAP immunoreactivity and IL -17A concentrations in the dentate gyrus were higher in the OLE group than those in the control group, but LPS-related increases in these concentrations were suppressed in the O-LPS group. The O-LPS group had higher cortical TAS and IL -4 concentrations. Conclusions: OLE suppressed LPS-related astrocyte and microglial activation in the hippocampus and cortex. The OLE-induced increase in cortical IL -4 concentrations indicates the induction of an anti-in fl ammatory phenotype of microglia. OLE may also modulate astrocyte and IL -17A functions, which could explain its opposing effects on hippocampal GFAP immunoreactivity and IL -17A concentrations when administered with or without LPS.
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    Depression and anxiety levels in woman under follow-up for breast cancer: relationship to coping with cancer and quality of life
    Karakoyun-Celik, O; Gorken, I; Sahin, S; Orcin, E; Alanyali, H; Kinay, M
    Aim The relation of anxiety and depression levels with characteristics of coping with the disease and quality of life were evaluated in women under follow-up for breast cancer. Materials and Methods Patients who had presented to the breast cancer polyclinics for follow-up were evaluated. The Beck Depression and the State-Trait Anxiety inventories were used in the evaluation of depression and anxiety levels. In order to evaluate their power to cope with cancer, the patients were questioned for a social support network. EORTC QLQ-C30 and QLQ-BR23 questionnaires were applied for quality of life evaluations. Results There were 23 (19%) patients with depression; 3 (2.5%) with grade I anxiety, 94 (77%) grade II, and 23 (19%) grade III anxiety, respectively. Depression and anxiety levels were affected by the following parameters: being unaccompanied by spouse for hospital follow-ups (P < 0.0001); request to get help by a psychologist (P = 0.02); presence of a person to share their problems (P < 0.0001); and using an alternative treatment (P = 0.04). In the quality of life evaluations, difficulty in sleeping, emotional status, fatigue, and body appearance were related with both depression and anxiety (P < 0.05 for all), whereas physical function (P = 0.002), role performance (P = 0.005), cognitive condition (P < 0.0001), social position (P < 0.0001), pain (P < 0.0001), general health (P < 0.0001), treatment methods (P = 0.001), future anxiety (P < 0.0001), and arm symptoms (P = 0.001) were negatively affected in patients with depression. Conclusion High depression and anxiety levels in patients under follow-up for breast cancer influence the coping with cancer and quality of life adversely.
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    Modelled and measured residual stresses in a bimaterial joint
    Sahin, S; Toparli, M; Ozdemir, I; Sasaki, S
    A finite element technique has been used to predict residual and thermal stresses due to welding. For this purpose, a steel-brass material couple was chosen and thin plates of the materials were hard brazed. The finite element study was carried out using two-dimensional models. After the temperature distributions as a result of welding were calculated, thermal and residual stress values obtained. Thermo-elasto-plastic formulations using a von-Mises yield criterion with linear isotropic-hardening were employed. For this deformation, the initial stress method was used and the kinematical Bauschinger effect was considered. The authors prepared all calculation programs using FORTRAN 77. To obtain residual stresses that occur during the welding, the hole-drilling strain-gage method was chosen and conducted in accordance with the ASTM Standard E 837-99. The agreement between the calculated results and the experimental data shows that the finite element analysis method is reliable. (C) 2002 Elsevier Science B.V. All rights reserved.
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    Introduction to nanojoining
    Sahin, S; Yavuz, M; Zhou, Y
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    Predictive Value of the TRACK Questionnaire as a Measure of Asthma Control in Preschool Aged Children
    Yilmaz, O; Turkeli, A; Sahin, S; Yuksel, H
    Assessment of asthma control in preschool children is important for therapeutic decisions. Aim of this study was to evaluate the predictive value of TRACK questionnaire scores for subsequent clinical parameters and to investigate the validity and reliability of the Turkish version of the TRACK questionnaire. We enrolled 100 children with asthma aged 4 years or younger in this cohort study. We recorded sociodemographic characteristics and clinical severity parameters. A pediatric allergist filled in the asthma severity scale and the caregiver of the child filled in the TRACK questionnaire. We called in the children again at the end of one month and recorded the same parameters and administered TRACK again. Uncontrolled asthma was defined as a TRACK score below 80. According to the TRACK score, 65% of the children had controlled asthma initially while at the end of the study 64.1% had controlled asthma. At the beginning of the study, all clinical parameters were worse in children with uncontrolled asthma according to TRACK score. Similarly, other objective clinical parameters during the following one month period were worse in children with initial uncontrolled asthma. Cronbach's alpha score for the TRACK questionnaire was 0.84. Turkish TRACK questionnaire is a valid and reliable tool that is predictive of short term asthma prognosis.
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    Investigation of the effect on boride layer of powder particle size used in boronizing with solid boron-yielding substances
    Meriç, C; Sahin, S; Yilmaz, SS
    In this study, the effect of particle size of powder used in the boronizing process with solid boron-yielding substances on the boride layer was investigated. Hot-shaped AISI 1020, AISI 1030, AISI 1040, and AISI 1050 structural steels were used as the base materials. EKabor HM powder was used as the boronizing agent, and was classified into four groups according to particle size. The boronizing process was carried out with each group at 900 degreesC for 2, 3, 4, and 5 h. The microstructure, microhardness, and layer thickness of the boronized materials were investigated. (C) 2001 Elsevier Science Ltd. All rights reserved.
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    The Effect of the Retrogression Process on the Wear Behaviour of a 7075 Aluminium Alloy
    Durmus, H; Uzun, RO; Sahin, S; Yüksel, N
    Retrogression and re-aging (RRA) process are applied in an attempt to enhance mechanical properties and corrosion resistance of 7075 aluminium alloys. In this study, retrogression and re-aging process have been applied to a 7075 aluminium alloy at 170 C for 5, 40, 80 min and wear resistance of RRA applied samples have been investigated by ball-on-disc wear test apparatus. Sliding distance has been chosen as 300 meters. Re-aging procedure has been carried out at 125 C for 10, 20 and 30 hours. Minimum wear loss has been obtained by retrogression for 40 min and aging for 30 hours.
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    A STUDY FOR BORONIZING PROCESS WITHIN NONEXTENSIVE THERMOSTATISTICS
    Kayacan, Ö; Sahin, S; Tastan, F
    In this study, diffusion mechanism of the boronizing process of AISI 1040 has been investigated. A nonlinear diffusion equation, which was proposed earlier, has been employed and compared with the experimental data. An interesting property of the diffusion equation used here is that it establishes a connection between the diffusion process and nonextensivity. The theoretical model also exhibits a possible connection between the exponents appeared in the differential equation and the entropic index. In this manner, the possible effects of nonextensivity on the boronizing process have been shown theoretically. We believe that a diffusion equation based on the nonextensive formalism is first applied to the boronizing process in literature.
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    Investigation of the boronizing effect on the abrasive wear behavior in cast irons
    Meric, C; Sahin, S; Backir, B; Koksal, NS
    One of the methods used to improve the surface properties of iron and steel is boronizing. Gray iron, ductile iron and compacted graphite iron were boronized with solid boron-yielding substances by pack-boronizing method. Commercial EKabor (R) 3 powder was used as the boronizing agent and the treatment was carried out at 900 degrees C for 2, 3, 4, 5 and 6 h. Thickness, microhardness and microstructure of the boride layer are investigated. Abrasive wear behavior of the boronized and unboronized cast irons were investigated. For this purpose, the specimens were tested on a pin-on disk test apparatus. SAE 1040 steel was used as the moving surface member. Abrasive wear tests were carried out at a fixed load and a fixed sliding speed. The weight loss was measured and worn surfaces were examined. (c) 2005 Elsevier Ltd. All rights reserved.