Serum Irisin Level Can Predict the Severity of Coronary Artery Disease in Patients with Stable Angina

Tolga Han Efe,Çağrı Yayla,Burak Açar,Göktuğ Ertem,Kadriye Gayretli Yayla,Engin Algül,Sefa Ünal,Murat Bilgin,Tolga Çimen,Özgür Kirbaş,Ekrem Yeter 대한심장학회 2017 Korean Circulation Journal Vol.47 No.1

Background and Objectives: The recently discovered myokine irisin has a proposed role in adipose tissue metabolism. The aim of this study was to evaluate the relationship between serum irisin level and the coronary artery severity in patients with stable coronary artery disease (CAD). Subjects and Methods: Sixty-three patients who underwent coronary angiography (CA) diagnosed with stable CAD and twenty-six patients with normal coronary artery (NCA) were enrolled in the study. Stable CAD patients were divided into two groups as high synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX) score (≥23) and lower SYNTAX score (<23). Serum irisin level measurement was carried out using human irisin colorimetric enzyme-linked immunosorbent assay (ELISA) commercial kit (AG-45A-0046EK-KI01, Adipogen, San Diego, CA, USA) as recommended by the manufacturer’s protocol. Results: The patients with stable CAD with a higher SYNTAX score (score ≥23) had significantly lower serum irisin levels (127.91±55.38 ng/mL), as compared the patients with a low SYNTAX score (score <23) (224.69±92.99 ng/mL) and control group (299.54±123.20 ng/mL). Irisin levels showed significant differences between all groups (p<0.001). Conclusion: Serum irisin level is an independent predictor of coronary artery severity in patients with stable CAD.

Investigation of low velocity impact behaviors of honeycomb sandwich composites

Tolga Topkaya,Murat Yavuz Solmaz 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

Honeycomb sandwich composites are used as significant structural members in advanced engineering applications. Thus, it is critical to determine how they behave under impact loading, in addition to other loads. In this study, low velocity impact loading behaviors of honeycomb sandwich composites were experimentally investigated. Almost all of the design parameters of honeycomb sandwich composites were investigated. The results indicated that the core thickness of honeycomb had no effect on the strength of the composite, and the parameter influencing the impact behavior of the specimen the most was the face sheet thickness. When the face sheet thickness of the specimen was increased, the most apparent strength increase was observed in the models using carbon fiber-reinforced composite face sheets. For all face sheet types subject to impact energy of 10 Joules, the upper face sheets of 0.5 mm-thick specimens were perforated.

Proportional Fair Scheduling Algorithm in OFDMA-BasedWireless Systems with QoS Constraints

Tolga Girici,Chenxi Zhu,Jonathan R. Agre,Anthony Ephremides 한국통신학회 2010 Journal of communications and networks Vol.12 No.1

In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.

Does the Oropharyngeal Fat Tissue Influence the Oropharyngeal Airway in Snorers? Dynamic CT Study

Tolga Aksoz,Huseyin Akan,Mehmet Celebi,Banu Baglan Sakan 대한영상의학회 2004 Korean Journal of Radiology Vol.5 No.2

An alternative evaluation of the LTB behavior of mono-symmetric beam-columns

Tolga Yilmaz,Nevzat Kiraç,Özgür Anil 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.5

Beam-columns are structural members subjected to a combination of axial and bending forces. Lateral-torsional buckling is one of the main failure modes. Beam-columns that are bent about its strong axis may buckle out of the plane by deflecting laterally and twisting as the values of the applied loads reach a limiting state. Lateral-torsional buckling failure occurs suddenly in beam-column elements with a much greater in-plane bending stiffness than torsional or lateral bending stiffness. This study intends to establish a unique convenient closed-form equation that it can be used for calculating critical elastic lateraltorsional buckling load of beam-column in the presence of a known axial load. The presented equation includes first order bending distribution, the position of the loads acting transversely on the beam-column and mono-symmetry property of the section. Effects of axial loads, slenderness and load positions on lateral torsional buckling behavior of beam-columns are investigated. The proposed solutions are compared to finite element simulations where thin-walled shell elements including warping are used. Good agreement between the analytical and the numerical solutions is demonstrated. It is found out that the lateral-torsional buckling load of beam-columns with mono-symmetric sections can be determined by the presented equation and can be safely used in design procedures.

Experimental Investigation of Impact Behaviour of RC Slab with Different Reinforcement Ratios

Tolga Yılmaz,Nevzat Kıraç,Özgür ANIL,R. Tuğrul Erdem,Gökhan Kaçaran 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.1

Reinforced concrete (RC) slabs may be exposed to the low-velocity impact load during their service periods. In low-velocity impact scenarios, the effect of strain rates has been remarkably higher than quasi-static loading because the loading duration is very short. Thus, structural responses and failure modes will be different. The present study aims to investigate dynamic response and failure modes of simply supported two-way RC slabs exposed to low-velocity impact load. In the experimental part of this study, nine RC slabs with the dimension of 1,000 × 1,000 × 80 mm were tested. The reinforcement ratio of RC slabs and the input impact energy applied to RC slabs were experimental variables investigated. A drop-weight test setup was utilized to apply impact load to RC slabs. By varying drop-height as 1,000, 1,250 and 1,500 mm, three different impact energies have been applied to RC slabs via a hammer of which weight is 84 kg. The time histories of the accelerations, displacements and impact loads were recorded. The dynamic responses obtained by tests and the failure modes observed has been interpreted in detail. Besides, a finite element model where explicit dynamic analysis is performed has been established for verification of the experimental results. There was observed good accordance between numerical and experimental results. Consequently, it is considered that the present finite element treatment can be used for the evaluation of the dynamic responses and failure modes of RC slabs exposed to low-velocity impact load.

Comparison of Coskun and Lichteinstein hernia repair methods for groin hernia

Tolga Dinc,Hayri Mukerrem Cete,Barı? Saylam,Mehmet Vasfi Ozer,Arife Polat Duzgun,Faruk Co?kun 대한외과학회 2015 Annals of Surgical Treatment and Research(ASRT) Vol.89 No.3

Purpose: Coskun hernia repair technique has been reported to be an effective new fascia transversalis repair with its short-term follow-up results. Our aim is to determine the results of Coskun hernia repair technique and to compare it with Lichtenstein technique. Methods: At this comparative retrospective study a total of 493 patients, who had groin hernia repair procedure using Coskun or Lichtenstein technique, between January 1999 and March 2010 were enrolled into the study. Patients were reached by telephone and invited to get a physical examination. Results: Out of 493 groin hernia repairs, 436 (88.5%) were carried out by residents and 57 (11.5%) by attending surgeons. Lichtenstein technique was the choice in 241 patients and 252 patients underwent Coskun hernia repair technique. Groin hernia recurrence was detected in 8 patients (3.1%) in Coskun hernia repair group and 7 patients (2.9%) in Lichtenstein group. Comparison of early complication rates in Coskun group (3.9%) and Lichtenstein group (4.5%) showed no significant difference. Late complication rates were significantly higher in Lichtenstein group (1.2% vs. 4.9%). The operation time was shorter in Coskun group (44 minutes) than in Lichtenstein group (60 minutes). Subgroup of patients, whose hernia repair operations were carried out by attending surgeons, had a recurrence rate of 0% and 3.8%, in Coskun group and Lichtenstein group, respectively. Conclusion: This study showed that Coskun hernia repair technique has a similar efficacy with Lichtenstein repair, on follow-up.

Mechanical properties of fiber/graphene epoxy hybrid composites

Tolga Topkaya,Yahya Hışman Çelik,Erol Kilickap 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

The aim of this study is to determine the effect of graphene nanoparticle (GNP) reinforcement on the mechanical properties of glass fiber reinforced polymer (GFRP), carbon fiber reinforced polymer (CFRP) and aramid fiber reinforced polymer (AFRP) composites commonly used in the space and defense industry. Accordingly, GFRP, CFRP and AFRP composites were produced by using hot pressing method. In addition, hybrid fiber composites were produced by adding 0.1 %, 0.2 % and 0.3 % GNP to these fiber reinforced composites. The tensile strength and modulus of elasticity of the composites were determined. The tensile damage fracture regions were analyzed by scanning electron microscopy (SEM) and energy distribution spectrum (EDS). It was observed that the addition of 0.2 wt. % GNP to GFRP and CFRP composites increased tensile strength and modulus of elasticity. However, the addition of 0.2 wt. % GNP to AFRP composites had no effect on the tensile strength; on the contrary, it partially reduced the tensile strength but increased the modulus of elasticity. On the fracture damage surfaces of the GFRP and CFRP composites and the GNP/GFRP and GNP/CFRP hybrid composites, the fibers were completely separated. On the damage surfaces of AFRP composite and GNP/AFRP hybrid composites, the fibers were deformed but these fibers were not separated from each other. From the EDS analysis, it was observed that the element C increased in the composites with the addition of GNP to the fiber reinforced composites.

Slide Session : OS-NEP-07 ; Nephrology : Effect of Donor Kidney Volume on Graft Functions in Living Donor Kidney Transplantation: 5 Years Follow Up

( Tolga Yildirim ),( Hadim Akoglu ),( Rahmi Yilmaz ),( Gonca Eldem ),( Tuncay Hazirolan ),( Tuncay Aki ),( Mustafa Arici ),( Bulent Altun ),( Yunus Erdem ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Immunosuppressive protocols decreased the rates of acute rejection in kidney transplantation however long term graft survival has not changed signifi cantly. Nephron underdosing may be one of the factors affecting the long term prognosis of the transplanted kidney. Aim of this study was to determine the impact of volume of transplanted kidney on long term allograft functions. Methods: The study was conducted among sixty-two living renal transplant recipients (41 male, 21 female; mean age 30.6±10.2 years) who underwent transplantation between years 2003-2007 and their respective donors (22 male, 40 female; age 41.9±9.9 years). Patients that suffered graft loss due to any cause within fi ve years after transplantation were excluded. Volume of the transplanted kidneys had been measured preoperatively via 3-D helical computerized tomography. Transplanted kidney volume/ recipient weight (Vol/weight) was calculated for each donor-recipient pair. Subjects were divided into two groups according to the median value of Vol/weight (2.35 cm3/ kg). Glomerular fi ltration rates (GFR) of the recipients were calculated for fi ve years. Results: First and third year GFR`s of the patients was significantly higher in Vol/ weight>2.35 cm3/kg group compared to Vol/weight<2.35 cm3/kg group (73.7±17.6 vs. 61.6±19.3, p=0.01 and 72.3±20.7 vs. 60.0±17.3, p=0.01 respectively). However fi fth year GFR was similar in both groups (64.5±16.9 and 56.6±21.7, p=0.11). There was a signifi cant correlation between Vol/weight and both fi rst and third year GFR`s (r=0.409, p<0.001 and r=0.429, p<0.001; respectively). The correlation was not observed with the fi fth year GFR (r=0.133, p=0.303). Conclusions: Volume of transplanted kidney adjusted for recipient weight is a signifi - cant predictor of early but not late graft functions.

Detecting Peripheral Arterial Disease in Primary Care: A Population Based Study

Tolga Vural,Makbule Neslişah Tan,Mehtap Kartal,Azize Dilek Güldal 대한가정의학회 2020 Korean Journal of Family Medicine Vol.41 No.1

Background: Peripheral arterial disease (PAD) can progress silently without any clinical symptoms. Ankle-brachial index (ABI) is the recommended method used in primary care. We aimed to determine the prevalence of PAD and its related risk factors in primary care. Methods: In this cross-sectional study, 250 participants aged ≥45 years were recruited randomly from the registered patients of family health center in a district of Izmir, Turkey. Patients’ demographic data, PAD symptoms, and PAD risk factors were obtained. The PAD group consisted of patients with ABI levels <0.9; the non-compressible artery (NCA) group consisted of patients with ABI levels >1.3. Results: The prevalence of PAD was 17.6% (22.5% in women and 11.1% in men), while that of NCA was 15.2% (12.7% in women and 25.0% in men). About 27.3% and 54.5% of patients with PAD did not have claudication and problems with walking distance, respectively. Of the NCA patients, 15.8% had problems with walking distance and 39.5% had claudication. Regression analysis revealed two predictors of PAD (age ≥65 years: odds ratio [OR], 3.51; 95% confidence interval [CI], 1.65–7.47; claudication: OR, 3.41; 95% CI, 1.58–7.39) and three predictors of NCA (age <65 years: OR, 2.55; 95% CI, 1.01–6.45; male sex: OR, 2.40; 95% CI, 1.10–5.25; triglyceride [TG] >200 mg/dL: OR, 4.11; 95% CI, 1.58–10.67). Conclusion: PAD had a prevalence of 17.6% and was associated with age ≥65 years and claudication. NCA had a prevalence of 15.2% and was associated with age <65 years, TG >200 mg/dL, and male sex.