• 제목/요약/키워드: MERT

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Response of steel pipeline crossing strike-slip fault in clayey soils by nonlinear analysis method

  • Hadi Khanbabazadeh;Ahmet Can Mert
    • Geomechanics and Engineering
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    • 제34권4호
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    • pp.409-424
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    • 2023
  • Response of the pipeline crossing fault is considered as the large strain problem. Proper estimation of the pipeline response plays important role in mitigation studies. In this study, an advanced continuum modeling including material non-linearity in large strain deformations, hardening/softening soil behavior and soil-pipeline interaction is applied. Through the application of a fully nonlinear analysis based on an explicit finite difference method, the mechanics of the pipeline behavior and its interaction with soil under large strains is presented in more detail. To make the results useful in oil and gas engineering works, a continuous pipeline of two steel grades buried in two clayey soil types with four different crossing angles of 30°, 45°, 70° and 90° with respect to the pipeline axis have been considered. The results are presented as the fault movement corresponding to different damage limit states. It was seen that the maximum affected pipeline length is about 20 meters for the studied conditions. Also, the affected length around the fault cutting plane is asymmetric with about 35% and 65% at the fault moving and stationary block, respectively. Local buckling is the dominant damage state for greater crossing angle of 90° with the fault displacement varying from 0.4 m to 0.55 m. While the tensile strain limit is the main damage state at the crossing angles of 70° and 45°, the cross-sectional flattening limit becomes the main damage state at the smaller 30° crossing angles. Compared to the stiff clayey soil, the fault movement resulting 3% tensile strain limit reach up to 40% in soft clayey soil. Also, it was seen that the effect of the pipeline internal pressure reaches up to about 40% compared to non-pressurized condition for some cases.

Micro-CT evaluation of the removal of root fillings using rotary and reciprocating systems supplemented by XP-Endo Finisher, the Self-Adjusting File, or Er,Cr:YSGG laser

  • Gulsen Kiraz;Bulem Ureyen Kaya;Mert Ocak;Muhammet Bora Uzuner;Hakan Hamdi Celik
    • Restorative Dentistry and Endodontics
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    • 제48권4호
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    • pp.36.1-36.15
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    • 2023
  • Objectives: This study aimed to compare the effectiveness of a single-file reciprocating system (WaveOne Gold, WOG) and a multi-file rotary system (ProTaper Universal Retreatment, PTUR) in removing canal filling from severely curved canals and to evaluate the possible adjunctive effects of XP-Endo Finisher (XPF), the Self-Adjusting File (SAF), and an erbium, chromium: yttrium, scandium, gallium garnet (Er,Cr:YSGG) laser using microcomputed tomography (µCT). Materials and Methods: Sixty-six curved mandibular molars were divided into 2 groups based on the retreatment technique and then into 3 based on the supplementary method. The residual filling volumes and root canals were evaluated with µCT before and after retreatment, and after the supplementary steps. The data were statistically analyzed with the t-test, Mann-Whitney U test, analysis of covariance, and factorial analysis of variance (p < 0.05). Results: PTUR and WOG showed no significant difference in removing filling materials (p > 0.05). The supplementary techniques were significantly more effective than reciprocating or rotary systems only (p < 0.01). The supplementary steps showed no significant differences in canal filling removal effectiveness (p > 0.05), but XPF showed less dentin reduction than the SAF and Er,Cr:YSGG laser (p < 0.01). Conclusions: The supplementary methods significantly decreased the volume of residual filling materials. XPF caused minimal changes in root canal volume and might be preferred for retreatment in curved root canals. Supplementary approaches after retreatment procedures may improve root canal cleanliness.

Efficiency of MVP ECG Risk Score for Prediction of Long-Term Atrial Fibrillation in Patients With ICD for Heart Failure With Reduced Ejection Fraction

  • Levent Pay;Ahmet Cagdas Yumurtas;Ozan Tezen;Tugba Cetin;Semih Eren;Goksel Cinier;Mert Ilker Hayiroglu;Ahmet Ilker Tekkesin
    • Korean Circulation Journal
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    • 제53권9호
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    • pp.621-631
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    • 2023
  • Background and Objectives: The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up. Methods: The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups. Results: The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group. Conclusions: The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

High-rate Single-Frequency Precise Point Positioning (SF-PPP) in the detection of structural displacements and ground motions

  • Mert Bezcioglu;Cemal Ozer Yigit;Ahmet Anil Dindar;Ahmed El-Mowafy;Kan Wang
    • Structural Engineering and Mechanics
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    • 제89권6호
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    • pp.589-599
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    • 2024
  • This study presents the usability of the high-rate single-frequency Precise Point Positioning (SF-PPP) technique based on 20 Hz Global Positioning Systems (GPS)-only observations in detecting dynamic motions. SF-PPP solutions were obtained from post-mission and real-time GNSS corrections. These include the International GNSS Service (IGS)-Final, IGS real-time (RT), real-time MADOCA (Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis), and real-time products from the Australian/New Zealand satellite-based augmentation systems (SBAS, known as SouthPAN). SF-PPP results were compared with LVDT (Linear Variable Differential Transformer) sensor and single-frequency relative positioning (SF-RP) solutions. The findings show that the SF-PPP technique successfully detects the harmonic motions, and the real-time products-based PPP solutions were as accurate as the final post-mission products. In the frequency domain, all GNSS-based methods evaluated in this contribution correctly detect the dominant frequency of short-term harmonic oscillations, while the differences in the amplitude values corresponding to the peak frequency do not exceed 1.1 mm. However, evaluations in the time domain show that SF-PPP needs high-pass filtering to detect accurate displacement since SF-PPP solutions include trends and low-frequency fluctuations, mainly due to atmospheric effects. Findings obtained in the time domain indicate that final, real-time, and MADOCA-based PPP results capture short-term dynamic behaviors with an accuracy ranging from 3.4 mm to 8.5 mm, and SBAS-based PPP solutions have several times higher RMSE values compared to other methods. However, after high-pass filtering, the accuracies obtained from PPP methods decreased to a few mm. The outcomes demonstrate the potential of the high-rate SF-PPP method to reliably monitor structural and earthquake-induced ground motions and vibration frequencies of structures.

Comparison of Carcass Characteristics, Meat Quality, and Blood Parameters of Slow and Fast Grown Female Broiler Chickens Raised in Organic or Conventional Production System

  • Comert, Muazzez;Sayan, Yilmaz;Kirkpinar, Figen;Hakan Bayraktar, O.;Mert, Selim
    • Asian-Australasian Journal of Animal Sciences
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    • 제29권7호
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    • pp.987-997
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    • 2016
  • The objective of the study was to compare the carcass characteristics, meat quality, and blood parameters of slow and fast grown female broiler chickens fed in organic or conventional production system. The two genotypes tested were medium slow-growing chickens (SG, Hubbard Red JA) and commercial fast-growing chickens (FG, Ross 308). Both genotypes (each represented by 400 chickens) were divided into two sub-groups fed either organic (O) or conventional (C) systems. Chickens of each genotype and system were raised in a semi environmentally controlled poultry house until 21 d of age and were assigned to 5 pens of 40 chickens each. Then, O system chickens were transferred into an open-side poultry house with an outdoor run. At 81 d of age, 10 female chickens from each genotype and from each production system (n = 40) were randomly chosen to provide material for analysis, and were weighed and brought to the slaughterhouse to assess carcass characteristics and meat quality. The blood parameters were determined by using 5 female chickens from each genotype and from each production system (n = 20). FG had the higher live weight, along with carcass, breast, and thigh-drumstick weights compared to SG (p<0.05). FG had the higher breast yield, whereas SG had the higher thigh-drumstick yield (p<0.05). The O system resulted in a higher amount of abdominal fat (p<0.05). In addition, the O system values were higher for dry matter, crude ash, crude protein, and $pH^{15}$ values in breast meat, and for crude ash, crude protein, and $pH^{15}$ values in drumstick meat (p<0.05). In addition, total saturated fatty acids, total mono-unsaturated fatty acids, and total omega 3 were significantly higher in the O system than in the C system. Thus, the O system showed a positive advantage compared to the C system regarding female chicken meat quality, primarily within the ash, protein, and total omega 3 fatty acid profiles. In conclusion, the present study indicated that the main factor affecting the carcass characteristics of female chickens was genotype, whereas the organic system contributed to enhanced meat quality. These findings provide a better understanding of the relative roles of genotype and production systems in female broiler characteristics, and might aid producers in designing their facilities to optimize yield and quality while maintaining acceptable animal welfare standards.

Awareness and Attitude Relating to the Human Papilloma Virus and its Vaccines Among Pediatrics, Obstetrics and Gynecology Specialists in Turkey

  • Tolunay, Orkun;Celik, Umit;Karaman, Seyfettin Senih;Celik, Tamer;Resitoglu, Salim;Donmezer, Cigdem;Aydin, Fahri;Baspinar, Huseyin;Mert, Mustafa Kurthan;Samsa, Hasan;Arli, Sefa
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권24호
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    • pp.10723-10728
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    • 2015
  • Background: To determine the level of knowledge on human papillomavirus (HPV) infection and vaccination, and the attitude towards HPV vaccination in pediatricians, obstetricians and gynecologists (OBG). Materials and Methods: Participants were administered a 40-question survey, investigating the demographic properties, the knowledge on the HPV infection-vaccination and attitudes towards vaccination. Results: The study enrolled a total of 228 participants (131 pediatricians and 97 OBGs). At a rate of 99.6%, the participants agreed with the fact that the HPV infection was the most common sexually transmitted disease and 33.8% of the participants had the opinion that the HPV vaccination should be administered only in women. The lowest level of HPV vaccine recommendation was among the pediatrics specialists (59.4%, p=0.012). When asked whether they would have their daughters receive HPV vaccination, 79.5% of the participants answered favorably; this rate was 36.7% for the sons. At a rate of 59.5% of the participants thought that the HPV vaccine needed to be included in the national vaccine schedule. Most of the participants (91.6%) had the idea that reduction of the vaccine costs would increase the vaccination frequency. Conclusions: We observed that the consideration of the costs and the prejudices relating to the inefficacy of vaccination as well as the inadequate level of knowledge were involved in the physicians' resistance to HPV vaccination. We believe that the healthcare professionals should be informed adequately to overcome false beliefs, thereby ensuring success of the HPV vaccine upon inclusion in the national vaccine schedule in the future.

Effects of soaking on a lime stabilized clay and implications for pavement design

  • Bozbey, Ilknur;Kelesoglu, M. Kubilay;Oztoprak, Sadik;Komut, Muhammet;Comez, Senol;Ozturk, Tugba;Mert, Aykan;Ocal, Kivilcim
    • Geomechanics and Engineering
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    • 제24권2호
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    • pp.115-127
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    • 2021
  • This paper investigates the effects of soaking on a lime stabilized high plasticity clay and evaluates the implications for pavement design. In this context, the soil was stabilized by 4%, 6% and 9% hydrated lime. The soil was pulverized in two different gradations so that representative field gradations could be simulated. Both soil pulverization levels passed the relevant field gradation criteria. Curing durations were chosen as 7 days, 28 days and 56 days. Two groups of samples were prepared and were tested in unconfined compression test apparatus to measure the strength and secant modulus at failure values. One of the groups was tested immediately after curing. The other group of samples were first cured and then subjected to soaking for ten days before testing. Visual observations were made on the samples during the soaking period. The results showed the superiority of fine soil pulverization over coarse soil pulverization for unsoaked conditions in terms of strength and modulus values. Soaking of the samples affected the unconfined compressive strength and modulus values based on lime content, curing duration and soil pulverization level. In soaked samples, fine soil pulverization resulted in higher strength and modulus values compared to coarse soil pulverization. However, even with fine soil pulverization, effects of soaking on modulus values were more significant. A new term named as "Soaking Influence Factor (SIF)" was defined to compare the reduction in strength and modulus due to soaking. The data was compared with the relevant design guidelines and an attempt was made to include Soaking Influence Factors for strength and modulus (SIFS and SIFM) into pavement design processes. Two equations which correlated secant modulus at failure to unconfined compressive strength were proposed based on the samples subjected to soaking. The results of this study showed that in order to decrease the diverse effects of soaking for lime stabilized soils, soil pulverization level should be kept as fine as possible in the field. Importance of proper drainage precautions in the pavements is highlighted for better performance of the pavements.

Medium and Long-Term Data from a Series of 96 Endoscopic Transsphenoidal Surgeries for Cushing Disease

  • Buruc Erkan;Muhammed Bayindir;Ebubekir Akpinar;Osman Tanriverdi;Ozan Hasimoglu;Lutfi Sinasi Postalci;Didem Acarer Bugun;Dilara Tekin;Sema Ciftci;Ilkay Cakir;Meral Mert;Omur Gunaldi;Esra Hatipoglu
    • Journal of Korean Neurosurgical Society
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    • 제67권2호
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    • pp.237-248
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    • 2024
  • Objective : Postoperative data on Cushing's disease (CD) are equivocal in the literature. These discrepancies may be attributed to different series with different criteria for remission and variable follow-up durations. Additional data from experienced centers may address these discrepancies. In this study, we present the results obtained from 96 endoscopic transsphenoidal surgeries (ETSSs) for CD conducted in a well-experienced center. Methods : Pre- and postoperative data of 96 ETSS in 87 patients with CD were included. All cases were handled by the same neurosurgical team between 2014 and 2022. We obtained data on remission status 3-6 months postoperatively (medium-term) and during the latest follow-up (long-term). Additionally, magnetic resonance imaging (MRI) and pathology results were obtained for each case. Results : The mean follow-up duration was 39.5±3.2 months. Medium and long-term remission rates were 77% and 82%, respectively. When only first-time operations were considered, the medium- and long-term remission rates were 78% and 82%, respectively. The recurrence rate in this series was 2.5%. Patients who showed remission between 3-6 months had higher long-term remission rates than did those without initial remission. Tumors >2 cm and extended tumor invasion of the cavernous sinus (Knosp 4) were associated with lower postoperative remission rates. Conclusion : Adenoma size and the presence/absence of cavernous sinus invasion on preopera-tive MRI may predict long-term postoperative remission. A tumor size of 2 cm may be a supporting criterion for predicting remission in Knosp 4 tumors. Further studies with larger patient populations are necessary to support this finding.