The Association between Subclinical Hypothyroidism and Epicardial Adipose Tissue Thickness

Erdal Belen,Aleks Degirmencioglu,Ertugrul Zencirci,Fatih Fahri Tipi,Özgür Altun,Gültekin Karakus,Ays¸en Helvacı,Aycan Esen Zencirci,Ezgi Kalaycıoglu 대한심장학회 2015 Korean Circulation Journal Vol.45 No.3

Background and Objectives: Subclinical hypothyroidism (SH) is considered to be a potential risk factor for cardiovascular disease. Epicardial adipose tissue (EAT) thickness is also closely related to cardiovascular disorders. The aim of this study was to evaluate whether SH is associated with higher EAT thickness. Subjects and Methods: Fifty-one consecutive patients with SH and 51 healthy control subjects were prospectively enrolled into this trial. Thyroid hormone levels, lipid parameters, body mass index, waist and neck circumference, and EAT thickness measured by echocardiography were recorded in all subjects. Results: Mean EAT thickness was increased in the SH group compared to the control group (6.7±1.4 mm vs. 4.7±1.2 mm, p<0.001). EAT thickness was shown to be correlated with thyroid stimulating hormone level (r=0.303, p=0.002). Multivariate logistic regression analysis revealed that EAT thickness was independently associated with SH {odds ratio (OR): 3.87, 95% confidence interval (CI): 1.92–7.78, p< 0.001; OR: 3.80, 95% CI: 2.18–6.62, p<0.001}. Conclusion: Epicardial adipose tissue thickness is increased in patients with SH compared to control subjects, and this increase in EAT thickness may be associated with the potential cardiovascular adverse effects of SH.

SMAD4 Suppresses AURKA-Induced Metastatic Phenotypes via Degradation of AURKA in a TGFβ-Independent Manner

Jia, Lina,Lee, Hun Seok,Wu, Chun Fu,Kundu, Juthika,Park, Sang Gyu,Kim, Ryong Nam,Wang, Li-Hui,Erkin, Ö,zgü,r Cem,Choi, Jong-Sun,Chae, Seoung Wan,Yang, Ho Bin,Choi, Yoon-La,Shin, Young Kee American Association for Cancer Research 2014 Molecular Cancer Research Vol.12 No.12

<P>SMAD4 has been suggested to inhibit the activity of the WNT/β-catenin signaling pathway in cancer. However, the mechanism by which SMAD4 antagonizes WNT/β-catenin signaling in cancer remains largely unknown. Aurora A kinase (AURKA), which is frequently overexpressed in cancer, increases the transcriptional activity of β-catenin/T-cell factor (TCF) complex by stabilizing β-catenin through the inhibition of GSK-3β. Here, SMAD4 modulated AURKA in a TGFβ-independent manner. Overexpression of SMAD4 significantly suppressed AURKA function, including colony formation, migration, and invasion of cell lines. In addition, SMAD4 bound to AURKA induced degradation of AURKA by the proteasome. A luciferase activity assay revealed that the transcriptional activity of the β-catenin/TCF complex was elevated by AURKA, but decreased by SMAD4 overexpression. Moreover, target gene analysis showed that SMAD4 abrogated the AURKA-mediated increase of β-catenin target genes. However, this inhibitory effect of SMAD4 was abolished by overexpression of AURKA or silencing of AURKA in SMAD4-overexpressed cells. Meanwhile, the SMAD4-mediated repression of AURKA and β-catenin was independent of TGFβ signaling because blockage of TGFβR1 or restoration of TGFβ signaling did not prevent suppression of AURKA and β-catenin signaling by SMAD4. These results indicate that the tumor-suppressive function of SMAD4 is mediated by downregulation of β-catenin transcriptional activity via AURKA degradation in a TGFβ-independent manner.</P><P><B>Implications:</B> SMAD4 interacts with AURKA and antagonizes its tumor-promoting potential, thus demonstrating a novel mechanism of tumor suppression. <I>Mol Cancer Res; 12(12); 1779–95. ©2014 AACR</I>.</P>

A Combined Generalized Regression Neural Network Wavelet Model for Monthly Streamflow Prediction

Özgür Kisi 대한토목학회 2011 KSCE Journal of Civil Engineering Vol.15 No.8

The ability of a combined model, Wavelet-Generalized Regression Neural Network (WGRNN), is investigated in the current study for the prediction of monthly streamflows. The WGRNN model is obtained by combining two methods, Discrete Wavelet Transform (DWT) and Generalized Regression Neural Network (GRNN), for one-month-ahead streamflow forecasting. The monthly flow data of two stations, the Gerdelli Station on the Canakdere River and the Isakoy Station on the Goksudere River, in the Eastern Black Sea region of Turkey are used in the study. The forecasts of the WGRNN model are tested using the Root Mean Square Error (RMSE),Variance Account For (VAF) and correlation coefficient (R) statistics and the results are compared with those of the single GRNN and Feed Forward Neural Network (FFNN). The comparison results revealed that the WGRNN performs better than the GRNN and FFNN models in monthly streamflow prediction. For the Gerdelli and Isakoy stations, it is found that the WGRNN models with RMSE = 5.31 m^3/s, VAF = 52.3%, R = 0.728 and RMSE = 3.36 m^3/s, VAF = 55.1%, R = 0.742 in the test period are superior in forecasting monthly streamflows than the best accurate GRNN models with RMSE = 6.39 m3/s, VAF = 30.1%, R = 0.553 and RMSE = 4.19 m^3/s, VAF = 30.1%, R = 0.549, respectively.

Structural repairing of damaged reinforced concrete beam- column assemblies with CFRPs

Özgür Yurdakul,Özgür Avşar 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.3

Depending on the damage type as well as the level of damage observed after the earthquake, certain measures should be taken for the damaged buildings. In this study, structural repairing of two different types of damaged RC beam-column assembly by carbon fiber-reinforced polymer sheets is investigated in detail as a member repairing technique. Two types of 1:1 scale test specimens, which represent the exterior RC beam-column connection taken from inflection points of the frame, are utilized. The first specimen is designed according to the current Turkish Earthquake Code, whereas the second one represents a deficient RC beam-column assembly. Both of the specimens were subjected to cyclic quasistatic loading in the laboratory and different levels of structural damage were observed. The first specimen displayed a ductile response with the damage concentrated in the beam. However, in the second specimen, the beam-column joint was severely damaged while the rest of the members did not attain their capacities. Depending on the damage type of the specimens, the damaged members were repaired by CFRP wrapping with different configurations. After testing the repaired specimens, it is found that former capacities of the damaged members were mostly recovered by the application of CFRPs on the damaged members.

Evaluation of the resin cement thicknesses and push-out bond strengths of circular and oval fiber posts in oval-shapes canals

Özgür Er,Kerem Kılıç,Halil İbrahim Kılınç,Tuğrul Aslan,Burak Sağsen 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.1

PURPOSE. The aim of this study was to evaluate whether the push-out bond strength varies between oval and circular fiber posts, and to examine the effect on the resin cement thicknesses around the posts. MATERIALS AND METHODS. Eighteen mandibular premolar roots were separated into two groups for oval and circular fiber posts systems. Post spaces were prepared and fiber posts were luted to the post spaces. Roots were cut horizontally to produce 1-mm-thick specimens. Resin cement thicknesses were determined with a metallographic optical microscope and push-out tests were done. RESULTS. No significant differences were observed in terms of push-out bond strength between the oval and circular fiber posts (P>.05) The resin cement thicknesses of the oval posts were greater than those of the circular posts group in the coronal, middle and apical specimens (P<.05). CONCLUSION. In the light of these results, it can be stated that resin cement thickness does not affect the push-out bond strength.

Design, Fabrication and Vision Based Operational Analysis of Novel Shape Memory Alloy Micro Grippers

Özgür Yurtsever,Haluk Küçük 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.9

Object grip, grasp, hold and place type of tasks incorporate specific engineering design concepts. Considering such principals, eight gripper mechanisms were designed and produced which can be classified as micro grippers due to their small workspace, precise grasping and holding abilities. Common characteristics of all the designs are that, without using any electric motor, the open–close operation is by virtue of shape-memory alloys. Each gripper is designed for different purposes with different operational principles of which four were initially open and the other four were initially closed configurations. Parametric studies were performed by changing the duty cycle and frequency of pulse width modulation using a signal generator followed by measurement of gripper jaw clearance, open–close period, average open–close velocities, gripping force, holding and lifting abilities of the designed gripper mechanisms. Jaw displacement and velocity parameters were computed by image processing of video records captured during the operation of the gripper mechanisms.

Nonlinear finite element analysis of loading transferred from column to socket base

Özgür ANIL,Burak UYAROĞLU 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.11 No.5

Since the beginning of the 90 s, depending on the growth of the industrial sector in Turkey,factory constructions have been increased. The cost of precast concrete buildings is lower than the steel ones for this reason the precast structural systems are used more. Precast concrete structural elements are mostly as strong as not to have damage in the earthquake but weakness of connections between elements causes unexpected damages of structure during earthquake. When looking at the previous researches, it can be seen that there is a lack of studies about socket type base connections although there were many experimental and analytical studies about the connections of precast structural elements. The aim of this study is to investigate the stress transfer mechanism between column and the socket base wall with finite element method. For the finite element analysis ANSYS software was used. A finite element model was created which is the simulation of experimental research executed by Canha et al. (2009) under vertical and horizontal forces. Results of experimental research and finite element analysis were compared to create a successful simulation of experimental program. After determining the acceptable parameters, models of socket bases were created. Model dimensions were chosen according to square section column sizes 400, 450, 500, 550 and 600 mm which were mostly used in industrial buildings. As a result of this study, stress distribution at center section of the socket base models were observed and it is found that stress distribution affects triangular at the half of socket bottom and top.

Strain distribution between CFRP strip and concrete at strengthened RC beam against shear

Özgür Anil,Nalan Bulut,Murat Ayhan 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.4

In recent years, CFRP material usage in strengthening applications gradually became widespread. Especially, the studies on the strengthening of shear deficient reinforced concrete beams with CFRP strips are chosen as a subject to numerous experimental studies and research on this subject are increased rapidly. The most important variable, that is affected on the failure mode of CFRP strips and that is needed for determining the shear capacity of the strengthened reinforced concrete beams, is the strain distribution between CFRP strips and concrete. Numerous experimental studies are encountered in the literature about the determination of strain distribution between CFRP strips and concrete. However, these studies mainly focused on the CFRP strips under axial tension. There are very limited numbers of experimental and analytic studies examining the strain distribution between concrete and CFRP strips, which are under combined stresses due to the effects of shear force and bending moment. For this reason, existing experimental study in the literature is used as model for ANSYS finite element software. Nonlinear finite element analysis of RC beams strengthened against shear with CFRP strips under reverse cyclic loading is performed. The strain distributions between CFRP strips and concrete that is obtained from finite element analysis are compared with the results of experimental measurements. It is seen that the experimental results are consisted with the results derived from the finite element analysis and important findings on the strain distribution profile are reached by obtaining strain values of many points using finite element method.

Effect of alkaline-earth oxides on firing behaviour of monoporosa wall tile bodies

Özgür Cengiz,Alpagut Kara 한양대학교 세라믹연구소 2018 Journal of Ceramic Processing Research Vol.19 No.3

For the production of ceramic wall tiles, effective sintering has become increasingly important in recent years to reduce firingtimes and/or peak firing temperatures and thus cope with high energy costs and environmental issues. This study was aimedto investigate the effects of alkaline-earth oxides on the fast-firing behaviour of wall tile bodies. To this end, several bodyformulations with different amounts of calcite and magnesite were prepared and fast fired under laboratory conditions. Thesintering behaviour of the representative formulations was evaluated using a double-beam non-contact optical dilatometer(ODHT). Thermal properties were characterised by TG-DTA. Phase and microstructural analyses were performed by XRDand SEM, respectively. The results showed that an optimum combination of the aforementioned earth alkalines has aconsiderable influence on lowering the peak firing temperature, shortening the firing cycle and improving the glaze qualityby lowering the decomposition temperature of carbonates in the formulations.

Estimation of compression strength of polypropylene fibre reinforced concrete using artificial neural networks

R. Tugrul Eredm,Erkan Kantar,Engin Gucuyen,Özgür ANIL 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.5

In this study, Artificial Neural Networks (ANN) analysis is used to predict the compression strength of polypropylene fibre mixed concrete. Polypropylene fibre admixture increases the compression strength of concrete to a certain extent according to mix proportion. This proportion and homogenous distribution are important parameters on compression strength. Determination of compression strength of fibre mixed concrete is significant due to the veridicality of capacity calculations. Plenty of experiments shall be completed to state the compression strength of concrete which have different fibre admixture. In each case, it is known that performing the laboratory experiments is costly and time-consuming. Therefore, ANN analysis is used to predict the 7 and 28 days of compression strength values. For this purpose, 156 test specimens are produced that have 26 different types of fibre admixture. While the results of 120 specimens are used for training process, 36 of them are separated for test process in ANN analysis to determine the validity of experimental results. Finally, it is seen that ANN analysis predicts the compression strength of concrete successfully.