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      • Serum Soluble Urokinase Plasminogen Activator Receptor Levels in Chronic Hepatitis B and C Patients and Relationship with Clinical Parameters

        ( Ali Pekcan Demiröz ),( Reyhan Öztürk ),( Şener Barut ),( Salih Cesur ),( Semanur Ayyıldız ),( Vildan Fidancı ),( Osman Demir ),( Ferdi Güneş ),( Laser Şanal ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

        Aims: Chronic hepatitis B (CHB) and C (CHC) are leading causes of liver cirrhosis and hepatocellular cancer. Defining of inflammatory activity and severity of disease is important for commencing antiviral treatment and monitoring the patient. Currently noninvasive serological markers to define disease activity are of great interest. In this study we aimed to determine soluble urokinase plasminogen activator receptor (suPAR) levels of patients with CHB and CHC, compare its levels with those of controls and to find if suPAR levels correlated with some laboratory parameters, histologic activity index (HAI) and fibrosis stage. Methods: Twenty-eight patients with CHB, 11 patients with CHC and 41 healthy subjects, eighty subjects in total, were included in the study. suPAR levels of all subjects were determined using commercial ELISA kits according to manufacturer’s instructions. Correlation between suPAR levels and parameters including AST, ALT, leukocyte count, thrombocyte count and liver histology scores were statistically analyzed. Results: Fifty percent of CHB patients were on oral antiviral treatment. Serum suPAR levels of both CHB and CHC patients were higher than controls (p< 0,001). Age, suPAR, HAI, AST, ALT, leukocyte and thrombocyte counts of subjects in different groups (CHB, CHC patients and controls) were shown in table 1. When we divided patients into two groups according to HBV DNA, suPAR levels were not different between patients with HBV DNA >1000 IU/ml and those with HBV DNA<1000 IU/ml. suPAR levels were not found to be correlated with AST, ALT levels, thrombocyte and leukocyte counts or histologic findings. Conclusions: In both CHB and CHC patients, suPAR levels were determined to be higher than healthy controls although suPAR was not found to be correlated with diseae activity or severity related parameters. However new wide scale studies are needed to investigate the relation between suPAR and disease activity or fibrosis stage.

      • KCI등재

        Effect of Mentoring Program on Ways of Coping with Stress and Locus of Control for Nursing Students

        Satı Demir,Sevil Güler Demir,Hülya Bulut,Filiz Hisar 한국간호과학회 2014 Asian Nursing Research Vol.8 No.4

        Purpose: This study evaluated the effectiveness of a 14-week mentoring program for first year nursing students and their ways of coping with stress and locus of control. Methods: The study was designed as a quasi-experimental study. Sixty-six first year students (mentees) and 66 fourth year students (mentors) were eligible to be in the mentoring program. Mentors and mentees contacted each other weekly, as required, to provide information and support. In order to determine the efficiency of the mentoring program, a Locus of Control Scale, the Ways of Coping Inventory and Mentoring Assessment Form were filled out by mentees. Results: In this study the mentoring program increased students' internal locus of control and active coping with stress. The increase in internal locus of control showed parallelism with students' behaviors of seeking social support. Conclusion: It is recommended that in nursing schools, the mentoring program be used as an additional program.

      • KCI등재

        Strengthening of reinforced concrete beams using external steel members

        Ali Demir,Emre Ercan,Duygu Dönmez Demir 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.4

        The objective of this study is to devise an alternative strengthening method to the ones available in the literature. So, external steel members were used to enhance both flexural and shear capacities of reinforced concrete (RC) beams having insufficient shear capacity. Two types of RC beams, one without stirrups and one with lacking stirrups, were prepared in the study. These beams were strengthened with external steel clamps devised by the authors and with external longitudinal reinforcements. Although the use of clamps alone didn’t have a significant effect on the load carrying capacity of the tested beams, the ductility increased approximately tenfold and the failure behavior changed from brittle to ductile. Although the use of clamps and longitudinal reinforcements together did not significantly increase the ductility of the beams, it approximately doubled their load capacities. The results of the experimental study were compared to the ones obtained from nonlinear finite element analysis (NLFEA) and it was observed that they were compatible. Finally, it can be concluded that the devised method could be applied to structural members as an alternative to methods in application due to lightness, low-cost, easy applicable and reliable.

      • KCI등재

        Influence of deposition conditions on nanostructured InSe thin films

        Kübra Çınar Demir,Emre Demir,Seniye Yüksel,Cevdet Coşkun 한국물리학회 2019 Current Applied Physics Vol.19 No.12

        In this study, nanostructured indium selenide (InSe) thin films were deposited on Indium tin oxide (ITO)-coated glass substrate using electrochemical deposition (ECD) from aqueous solution containing In(SO4)3.H2O and SeO2. The effects of deposition potential (−0.70 to −1.35 V), time (30-3600 s), temperature (25-80 °C) and pH (2.58 for A samples; 2 for B samples and 1.45 for C samples) on growth of the InSe thin films were examined in terms of their structural, morphological and optical properties. X-ray diffraction (XRD) analysis confirmed that the InSe thin films are in polycrystalline structure. It was found that the values of grain size decreased and the full width half maximum (FWHM) values increased with the increasing deposition potential. According to the absorption measurements, optical properties of the thin films varied with changes in deposition conditions. Based on the atomic force microscopy (AFM) and the scanning electron microscopy (SEM) images, surface morphology of the thin films was influenced by deposition potential and pH of the electrolyte, and nonhomogeneous depositions distributed across the entire surface were observed. In addition, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FT-IR) analyses were used to further examine crystal quality, vibration, chemical binding conditions, In/Se orientation and structure of the prepared InSe thin films. When Raman results are examined, the B12 sample shows a more intensity and narrow peak at 248 cm−1. XPS measurements sowed that A6 sample exhibited more growth in low potential for a long time and better film stoichiometry compared to the other three samples. Also, FT-IR studies prove the presence of InSe. According to the results, the film did not form at low temperatures and short times. However, the film formation began with the increasing deposition temperature and time at the low potential value of −0.730 V. But, it is clear that a high quality film can be obtained in cathodic potential with −1.3 V and shorter deposition time with 300 s at room temperature respectively. Overall results showed that the high quality thin films can be obtained by the ECD technique. However, deposition conditions must be sensitively adjusted to control morphology of the electrodeposited nanoparticles.

      • Does Immunohistochemistry Provide Additional Prognostic Data in Gastrointestinal Stromal Tumors?

        Demir, Lutfiye,Ekinci, Nese,Erten, Cigdem,Kucukzeybek, Yuksel,Alacacioglu, Ahmet,Somali, Isil,Can, Alper,Dirican, Ahmet,Bayoglu, Vedat,Akyol, Murat,Cakalagaoglu, Fulya,Tarhan, Mustafa Oktay Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

        Background: To investigate the predictive and prognostic effects of clinicopathologic and immunohistochemical (IHC) features in patients with gastrointestinal stromal tumours (GISTs). Materials and Methods: Fifty-six patients who were diagnosed with GIST between 2002 and 2012 were retrospectively evaluated. Relationships between clinicopathologic/immunohistochemical factors and prognosis were investigated. Results: Median overall survival (OS) of the whole study group was 74.9 months (42.8-107.1 months), while it was 95.2 months in resectable and 44.7 months in metastatic patients respectively (p=0.007). Epitheliolid tumor morphology was significantly associated with shortened OS as compared to other histologies (p=0.001). SMA(+) tumours were significantly correlated with low (<10/50HPF) mitotic activity (p=0.034). Moreover, SMA(+) patients tended to survive longer and had significantly longer disease-free survival (DFS) times than SMA (-) patients (37.7 months vs 15.9 months; p=0.002). High Ki-67 level (${\geq}30%$) was significantly associated with shorter OS (34 vs 95.2 months; 95%CI; p=0.001). CD34 (-) tumours were significantly associated with low proliferative tumours (Ki-67<%10) (p=0.026). Median PFS (progression-free survival) of the patients who received imatinib was 36 months (27.7-44.2 months). CD34 (-) patients had significantly longer PFS times than that of negative tumours; (50.8 vs 29.8 months; p=0.045). S100 and desmin expression did not play any role in predicting the prognosis of GISTs. Multivariate analysis demonstrated that ${\geq}10/50HPF$ mitotic activity/HPF was the only independent factor for risk of death in GIST patients. Conclusions: Despite the negative prognostic and predictive effect of high Ki-67 and CD34 expression, mitotic activity remains the strongest prognostic factor in GIST patients. SMA positivity seems to affect GIST prognosis positively. However, large-scale, multicenter studies are required to provide supportive data for these findings.

      • SCIESCOPUS

        Failure analysis of steel column-RC base connections under lateral cyclic loading

        Demir, Serhat,Husem, Metin,Pul, Selim Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.4

        One of the most important structural components of steel structures is the column-base connections which are obliged to transfer horizontal and vertical loads safely to the reinforced concrete (RC) or concrete base. The column-base connections of steel or composite steel structures can be organized both moment resistant and non-moment resistant leading to different connection styles. Some of these connection styles are ordinary bolded systems, socket systems and embedded systems. The structures are frequently exposed to cycling lateral loading effects causing fatal damages on connections like columns-to-beams or columns-to-base. In this paper, connection of steel column with RC base was investigated analytically and experimentally. In the experiments, bolded connections, socket and embedded connection systems are taken into consideration by applying cyclic lateral loads. Performance curves for each connection were obtained according to experimental and analytical studies conducted and inelastic behavior of connections was evaluated accordingly. The cyclic lateral performance of the connection style of embedding the steel column into the reinforced concrete base and strengthening of steel column in upper level of base connection was found to be higher and effective than other connection systems. Also, all relevant test results were discussed.

      • KCI등재

        Clinical evaluation of efficacy of transcortical anesthesia for the extraction of impacted mandibular third molars: a randomized controlled trial

        Demir, Esin,Ataoglu, Hanife The Korean Dental Society of Anesthsiology 2020 Journal of Dental Anesthesia and Pain Medicine Vol.20 No.1

        Background: This study aimed to compare the pain levels during anesthesia and the efficacy of the QuickSleeper intraosseous (IO) injection system and conventional inferior alveolar nerve block (IANB) in impacted mandibular third molar surgery. Methods: This prospective randomized clinical trial included 30 patients (16 women, 14 men) with bilateral symmetrical impacted mandibular third molars. Thirty subjects randomly received either the IO injection or conventional IANB at two successive appointments. A split-mouth design was used in which each patient underwent treatment of a tooth with one of the techniques and treatment of the homologous contralateral tooth with the other technique. The subjects received 1.8 mL of 2% articaine. Subjects' demographic data, pain levels during anesthesia induction, tooth extractions, and mouth opening on postoperative first, third, and seventh days were recorded. Pain assessment ratings were recorded using the 100-mm visual analog scale. The latency and duration of the anesthetic effect, complications, and operation duration were also analyzed in this study. The duration of anesthetic effect was considered using an electric pulp test and by probing the soft tissue with an explorer. Results: Thirty patients aged between 18 and 47 years (mean age, 25 years) were included in this study. The IO injection was significantly less painful with lesser soft tissue numbness and quicker onset of anesthesia and lingual mucosa anesthesia with single needle penetration than conventional IANB. Moreover, 19 out of 30 patients (63%) preferred transcortical anesthesia. Mouth opening on postoperative first day was significantly better with intraosseous injection than with conventional IANB (P = 0.013). Conclusion: The IO anesthetic system is a good alternative to IANB for extraction of the third molar with less pain during anesthesia induction and sufficient depth of anesthesia for the surgical procedure.

      • SCIESCOPUS

        Bearing capacity of footing supported by geogrid encased stone columns on soft soil

        Demir, Ahmet,Sarici, Talha Techno-Press 2017 Geomechanics & engineering Vol.12 No.3

        The stone columns are increasingly being used as a soil improvement method for supporting a wide variety of structures (such as road embankment, buildings, storage tanks etc.) especially built on soft soil. Soil improvement by the stone column method overcomes the settlement problem and low stability. Nevertheless, stone column in very soft soils may not be functional due to insufficient lateral confinement. The required lateral confinement can be overcome by encasing the stone column with a suitable geosynthetic. Encasement of stone columns with geogrid is one of the ideal forms of improving the performance of stone columns. This paper presents the results of a series of experimental tests and numerical analysis to investigate the behavior of stone columns with and without geogrid encasement in soft clay deposits. A total of six small scale laboratory tests were carried out using circular footing with diameters of 0.05 m and 0.1 m. In addition, a well-known available software program called PLAXIS was used to numerical analysis, which was validated by the experimental tests. After good validation, detailed of parametric studies were performed. Different parameters such as bearing capacity of stone columns with and without geogrid encasement, stiffness of geogrid encasement, depth of encasement from ground level, diameter of stone columns, internal friction angle of crushed stone and lateral bulging of stone columns were analyzed. As a result of this study, stone column method can be used in the improvement of soft ground and clear development in the bearing capacity of the stone column occurs due to geogrid encasement. Moreover, the bearing capacity is effected from the diameter of the stone column, the angle of internal friction, rigidity of the encasement, and depth of encasement. Lateral bulging is minimized by geogrid encasement and effected from geogrid rigidity, depth of encasement and diameter of the stone column.

      • SCIESCOPUSKCI등재

        Modeling the Catalytic Activity and Kinetics of Lipase(Glycerol-Ester Hydrolase)

        Demirer, Goksel N.,Duran, Metin,Tanner, Robert D. The Korean Society for Biotechnology and Bioengine 1996 Biotechnology and Bioprocess Engineering Vol.1 No.1

        In order to design industrial scale reactors and proceises for multi-phase biocatalytic reactions, it is essential to understand the mechanisms by which such systems operate. To il-lustrate how such mechanisms can be modeled, the hydrolysis of the primary ester groups of triglycerides to produce fatty acids and monoglycerides by lipased (glycerol-ester hydrolase) catalysis has been selected as an example of multiphase biocatalysis. Lipase is specific in its behavior such that it can act only on the hydrolyzed (or emulsified) part of the substrate. This follows because the active center of the enzyme is catalytically active only when the substrate contacts it in its hydrolyzed form. In other words, lipase acts only when it can shuttleback and forth between the emulsion phase and the water phase, presumably within an interphase or boundary layer between these two phases. In industrial applications lipase is employed as a fat splitting enzyme to remove fat stains from fabrics, in making cheese, to flavor milk products, and to degrade fats in waste products. Effective use of lipase in these processes requires a fundamental understanding of its kinetic behavior and interactions with substrates under various environmental conditions. Therefore, this study focuses on modeling and simulating the enzymatic activity of the lipase as a step towards the basic understanding of multi-phase biocatalysis processes.

      • SCIESCOPUS

        Uplift response of multi-plate helical anchors in cohesive soil

        Demir, Ahmet,Ok, Bahadir Techno-Press 2015 Geomechanics & engineering Vol.8 No.4

        The use of helical anchors has been extensively beyond their traditional use in the electrical power industry in recent years. They are commonly used in more traditional civil engineering infrastructure applications so that the advantages of rapid installation and immediate loading capability. The majority of the research has been directed toward the tensile uplift behaviour of single anchors (only one plate) by far. However, anchors commonly have more than one plate. Moreover, no thorough numerical and experimental analyses have been performed to determine the ultimate pullout loads of multi-plate anchors. The understanding of behavior of these anchors is unsatisfactory and the existing design methods have shown to be largely inappropriate and inadequate for a framework adopted by engineers. So, a better understanding of helical anchor behavior will lead to increased confidence in design, a wider acceptance as a foundation alternative, and more economic and safer designs. The main aim of this research is to use numerical modeling techniques to better understand multi-plate helical anchor foundation behavior in soft clay soils. Experimental and numerical investigations into the uplift capacity of helical anchor in soft clay have been conducted in this study. A total of 6 laboratory tests were carried out using helical anchor plate with a diameter of 0.05 m. The results of physical and computational studies investigating the uplift response of helical anchors in soft clay show that maximum resistances depend on anchor embedment ratio and anchor spacing ratio S/D. Agreement between uplift capacities from laboratory tests and finite element modelling using PLAXIS is excellent for anchors up to embedment ratios of 6.

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