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      • KCI등재후보SCIE

        The Reconstruction of Nasal Septal Perforation with High Density Porous Polyethylene Covered with Fascia Lata: An Experimental Study on Rabbit Model

        Güven,Yildirim,Vedat,Onar,Ibrahim,Sayin,Suzan,Deniz,Onol,Tamer,Aydin 대한이비인후과학회 2011 Clinical and Experimental Otorhinolaryngology Vol.4 No.3

        Objectives. Evaluation of a new material, high-density porous polyethylene (HDPP), which is covered with fascia lata, for experimental nasal septal perforation closure. Methods. Twenty New Zealand albino rabbits were included and divided into study and control groups. A lateral incision was made from the lateral aspect of the left nares to the incisura nasomaxillaris. After exposure of the cavum nasi,the nasal mucoperichondrium was elevated bilaterally. A full-thickness 0.5×0.5-cm perforation was created over the septum nasi with a No. 11 surgical blade. A fascia lata graft was used for the study group. The HDPP was covered with fascia lata and placed under the elevated mucosa. HDPP without a fascial covering was used in the control group. Four months after the procedure, magnetic resonance imaging was performed to evaluate resorption of the material. The animals were sacrificed, and the nasal septum was completely removed. Macroscopic and histopathological examinations were performed on the nasal septum. Results. All rabbits had survived after the 4-month period. Macroscopically, nine of 10 (90%) perforations were closed in the fascia lata-covered HDPP group. Histopathological examination of these nine rabbits revealed that the continuity of cartilage was disturbed in the perforation areas. Granulation tissue was inverted in areas in which the cartilage continuity was disturbed. The HDPP had remained intact at the edge of the perforation. In the HDPP group, six of 10 implants were still perforated (60%) and four (40%) were closed. The fascia lata-covered HDPP implant had a significantly higher perforation closure rate than that of the HDPP implant alone (P<0.05). Conclusion. In cases of septal perforation, it is better to cover the HDPP implant with fascia lata. This covered implant can be used for the repair of nasal septal perforations. HDPP implants are easy to work with and avoid the increased operative time and morbidity associated with harvesting autografts.

      • KCI등재

        The use of platelet rich plasma in the treatment of immature tooth with periapical lesion: a case report

        Günseli,Güven,Polat,Ceren,Yıldırım,Özlem,Martı,Akgün,Ceyhan,Altun,Didem,Dinçer,Cansel,Köse,Özkan 대한치과보존학회 2014 Restorative Dentistry & Endodontics Vol.39 No.3

        This study describes the treatment of an immature permanent tooth with periapical lesion which was treated with regenerative approach using platelet rich plasma (PRP). The root canal of immature human permanent tooth with periapical lesion was gently debrided of necrotic tissue and disinfected with 2.5% NaOCl, and then medicated with triple antibiotic paste comprised of ciprofloxacin, metronidazole, and tetracycline. When the tooth was asymptomatic, PRP and mineral trioxide aggregate (MTA) were placed into the root canal. Six months after PRP treatment, radiographical examination revealed resolution of the radiolucency and progressive thickening of the root wall and apical closure. Our findings suggest that PRP can be used for the treatment of immature permanent teeth with periapical lesion, as part of a regenerative endodontic treatment procedure.

      • KCI등재SCOPUS

        Thiol/Disulfide Homeostasis in Bipolar and Unipolar Depression

        Gamze,Erzin,Güven,Özkaya,Canan,Topçuoğlu,Rabia,Nazik,Yüksel,Özcan,Erel,Emine,Feyza,Yurt,Erol,Göka,Sinan,Gülöksüz 대한정신약물학회 2020 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.18 No.3

        Objective: Bipolar disorder and unipolar depressive disorder are complex phenotypes. There appear to be phenotypical, mechanistic, and therapeutic differences between bipolar depression (BD) and unipolar depression (UD). There is a need for understanding the underlying biological variation between these clinical entities. The role of oxidative processes underlying bipolar disorder and depression has been demonstrated. Thiol-disulfide homeostasis (TDH) is a recent oxidative stress marker. In this study, we aimed to inspect patients with bipolar depression and unipolar depression in terms of thiol-disulfide balance and to compare them with healthy controls. Methods: Patients admitted to the outpatient clinic of Ankara Numune Training and Research Hospital and diagnosed either as a depressive episode with bipolar disorder (n = 37) or unipolar depression (n = 24) according to DSM-5 criteria, along with healthy controls (HC) (n = 50), were included in the study. Native thiol, total thiol, and disulfide levels were compared across the groups. Results: In comparison to HC, both BD and UD groups had higher disulfide levels, disulfide/native thiol ratio, and disulfide/total thiol ratio. No significant differences between BD and UD were detected in terms of disulfide level, disulfide/ native thiol ratio, and disulfide/total thiol ratio. Conclusion: Increased levels of disulfide, native thiol, and disulfide/total thiol ratios compared to healthy controls in both UD and BD groups may be indicative of the presence of oxidative damage in these two clinical conditions. To clarify the role of oxidative stress in the pathophysiology of depressive disorders and investigate TDH, longitudinal studies in patients with medication-free UD and BD are required.

      • KCI등재

        An Analysis of Myocardial Efficiency in Patients with Severe Asymptomatic Mitral Regurgitation

        Rengin,Çetin,Güvenç,Emre,Aruğaslan,Tolga,Sinan,Güvenç,Fatma,Özpamuk,Karadeniz,Hülya,Kaşıkçıoğlu,Neşe,Çam 한국심초음파학회 2020 Journal of Cardiovascular Ultrasound Vol.28 No.4

        BACKGROUND: It is difficult to determine left ventricular systolic performance in patients with severe mitral regurgitation (MR) since left ventricular ejection fraction (EF) could be preserved until the end stages of the disease. Myocardial efficiency (MEf) describes the amount of external work (EW) done by the left ventricle per unit of oxygen consumed (mVO2). In the present study, we aimed to investigate MEf in patients with asymptomatic severe MR using a novel echocardiographic method. METHODS: A total of 27 patients with severe asymptomatic MR and 26 healthy volunteers were included in this cross-sectional study. EW was measured using stroke volume and blood pressure, while mVO2 was estimated using double product and left ventricular mass. RESULTS: There were no differences between the groups with regards to EF (66% ± 5% vs. 69% ± 7%), while MEf was significantly reduced in patients with severe MR (25% ± 11% vs. 44% ± 12%, p < 0.001). This difference was maintained even after adjustment for age, gender and body surface area (adjusted ̅ : 0.44, 95% CI: 0.39–0.49 for controls and adjusted ̅ : 0.24, 95% CI: 0.19–0.29 for patients with severe MR). Further analysis showed that this reduction was due to an increase in total mVO2 in the severe MR group. MEf of thepatients who were both on β-blockers and angiotensin converting enzyme inhibitors/angiotensin receptor blockers were higher than those who were not on any drugs, but this difference was not statistically significant (32% ± 15% vs. 23% ± 9%, p = 0.41). CONCLUSIONS: MEf was significantly lower in patients with asymptomatic severe MR and preserved EF.

      • KCI등재SCOPUS

        DESIGN AND EVALUATION OF ROBUST COOPERATIVE ADAPTIVE CRUISE CONTROL SYSTEMS IN PARAMETER SPACE

        Mümin,Tolga,Emirler,Levent,Güvenç,Bilin,Aksun,Güvenç 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.2

        This paper is on the design of cooperative adaptive cruise control systems for automated driving of platoons of vehicles in the longitudinal direction. Longitudinal models of vehicles with simple dynamics, an uncertain first order time constant and vehicle to vehicle communication with a communication delay are used in the vehicle modeling. A robust parameter space approach is developed and applied to the design of the cooperative adaptive cruise control system. D-stability is chosen as the robust performance goal and the feedback PD controller is designed in controller parameter space to achieve this D-stability goal for a range of possible longitudinal dynamics time constants and different values of time gap. Preceding vehicle acceleration is sent to the ego vehicle using vehicle to vehicle communication and a feedforward controller is used in this inter-vehicle loop to improve performance. Simulation results of an eight vehicle platoon of heterogeneous vehicles are presented and evaluated to demonstrate the efficiency of the proposed design method. Also, the proposed method is compared with a benchmark controller and the feedback only controller. Time gap regulation and string stability are used to assess performance and the effect of the vehicle to vehicle communication frequency on control system performance is also investigated.

      • KCI등재SCOPUS

        LATERAL STABILITY CONTROL OF FULLY ELECTRIC VEHICLES

        M.,T.,EM,RLER,K.,KAHRAMAN,M.,ENTÜRK,O.,U.,ACAR,B.,AKSUN,GÜVENÇ,L.,GÜVENÇ,B.,EFEND,O,LU 한국자동차공학회 2015 International journal of automotive technology Vol.16 No.2

        The problem of vehicle lateral stability control for fully electric vehicles is addressed in this paper using two different approaches. One of them is a novel integrated lateral stability control (ILSC) system and the second one is a regenerative braking based lateral stability control system (RB-LSC). The proposed ILSC system is based on corrective yaw moment calculation, braking torque distribution and electric motor torque reduction. The proposed second method – RB-LSC - is a simpler method than the ILSC system. In this method, electric motor torque is regulated according to the vehicle side slip error and/or the vehicle yaw rate error. The performances of the proposed methods are evaluated under severe road conditions and extreme maneuvers using the commercially available CarSim vehicle dynamics software. The results show that the proposed control systems improve vehicle lateral stability significantly.

      • [Keynote Speeches] RETENTION AIDS:FROM ART TO SCIENCE

        Theo,G.M,van,de,Ven 한국펄프·종이공학회 1999 한국펄프종이학회 기타 간행물 Vol.- No.-

        Our knowledge about the mechanisms by which retention aids function in wet-end papermaking has been increasing rapidly. Although originally many retention aids were introduced without little understanding of how they act, nowadays a clear scientific understanding is emerging. We can say that the use of retention aids has passed from an art which depended much on experience and intuition, to a science, which involves the principles of colloid and polymer science. Various examples of our increased understanding of PEO-based retention. aids, cationic. poly-and microparticulate retention aid systems are being discussed.

      • SCIESCOPUSKCI등재

        Comparison of retention forces with various fabrication methods and materials in double crowns

        Melahat,Çelik,Güven,Meral,Tuna,Ergun,Bozdağ,Gizem,Nur,Öztürk,Gulsen,Bayraktar 대한치과보철학회 2017 The Journal of Advanced Prosthodontics Vol.9 No.4

        PURPOSE. The purpose of this study was to analyze the retention force changes and wear behaviours of doublecrown systems over long-term use. MATERIALS AND METHODS. Ten groups, each consisting of six samples, were evaluated. Specifically, casting gold alloy primary crown - casting gold alloy secondary crown (AA), laser sintering primary crown - laser sintering secondary crown (LL), casting Cr alloy primary crown - casting Cr alloy secondary crown, (CC) zirconia primary crown - electroformed secondary crown (ZA), and CAD/CAM titanium alloy primary crown - CAD/CAM titanium alloy secondary crown (TT) groups were evaluated at cone angles of 4° and 6°. The samples were subjected to 5,000 insertion-separation cycles in artificial saliva, and the retention forces were measured every 500 cycles. The wear levels were analyzed via SEM at the beginning and end of the 5,000 cycles. RESULTS. In all samples, the retention forces increased when the conus angle decreased. The highest initial and final retention force values were found in the LL-4° group (32.89 N-32.65 N), and the lowest retention force values were found in the ZA6° group (5.41 N-6.27 N). The ZA groups' samples showed the least change in the retention force, and no wear was observed. In the other groups, wear was observed mostly in the primary crowns. CONCLUSION. More predictable, clinically relevant, and less excursive retention forces can be observed in the ZA groups. The retention force values of the LL groups were statically similar to those of the other groups, except the ZA groups.

      • KCI등재SCIE

        Efficacy of Trimetazidine Dihydrochloride for Relieving Chronic Tinnitus: A Randomized Double-Blind Study

        Tolgar,Lütfi,Kumral,Güven,Yıldırım,Güler,Berkiten,Ziya,Saltürk,Enes,Ataç,Yavuz,Atar,Yavuz,Uyar 대한이비인후과학회 2016 Clinical and Experimental Otorhinolaryngology Vol.9 No.3

        Objectives: To evaluate the efficacy of trimetazidine dihydrochloride as a treatment for chronic tinnitus. Methods: A total of 97 chronic tinnitus patients were evaluated in this randomized, prospective, double-blind, placebo-controlled trial. After assessing for eligibility, 82 patients were randomly assigned into placebo or trimetazidine groups according to the medication. The trimetazidine group received 20×3 mg/day per oral trimetazidine dihydrochloride and the placebo group received 20×3 mg/day per oral placebo for 3 months. Tinnitus handicap inventory (THI), visual analogue scale (VAS) questionnaires and audiometric results were used to determine the effectiveness of trimetazidine treatment. Results: The study group comprised 82 tinnitus subjects, 42 (51%) of whom received trimetazidine dihydrochloride and 40 (49%) who received placebo. There was no significant difference between placebo and trimetazidine groups in THI grade and VAS (both pre- and posttreatment scores) (P>0.05) and no significant improvement was observed in subjective loudness score in either group (P>0.05). Additionally there was no significant difference between groups in pre- and posttreatment pure tone hearing thresholds at all measured frequencies (P>0.05). Conclusion: Trimetazidine dihydrochloride therapy was ineffective for relieving chronic tinnitus.

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