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Predictors of Intra-Aortic Balloon Pump Insertion in Coronary Surgery and Mid-Term Results
Kazim Ergüneş,Ismail Yurekli,Ersin Celik,Ufuk Yetkin,Levent Yilik,Ali Gurbuz 대한흉부외과학회 2013 Journal of Chest Surgery (J Chest Surg) Vol.46 No.6
Background: We aimed to investigate the preoperative, operative, and postoperative factors affecting intra-aortic balloon pump (IABP) insertion in patients undergoing isolated on-pump coronary artery bypass grafting (CABG). We also investigated factors affecting morbidity, mortality, and survival in patients with IABP support. Methods: Between January 2002 and December 2009, 1,657 patients underwent isolated CABG in İzmir Katip Celebi University Atatürk Training and Research Hospital. The number of patients requiring support with IABP was 134 (8.1%). Results: In a multivariate logistic regression analysis, prolonged cardiopulmonary bypass time and prolonged operation time were independent predictive factors of IABP insertion. The postoperative mortality rate was 35.8% and 1% in patients with and without IABP support, respectively (p=0.000). Postoperative renal insufficiency, prolonged ventilatory support, and postoperative atrial fibrillation were independent predictive factors of postoperative mortality in patients with IABP support. The mean follow-up time was 38.55±22.70 months and 48.78±25.20 months in patients with and without IABP support, respectively. The follow-up mortality rate was 3% (n=4) and 5.3% (n=78) in patients with and without IABP support, respectively. Conclusion: The patients with IABP support had a higher postoperative mortality rate and a longer length of intensive care unit and hospital stay. The mid-term survival was good for patients surviving the early postoperative period.
Mehmet Ali Hinis,Kadri Yurekli 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.1
The probability of the occurrence belonging to heavy rainfalls that directly triggers the flood is estimated with the common assumption that the process by which it occurred is under stationary conditions. By accepting this threat as if it does not exist in our globe, which is faced with the reality of global warming and climate change, estimating the required design values in the construction of hydraulic structures with frequency analysis of the relevant data would cause the failure of the water-related structures. This study was carried out to come up with how the regional and site-based frequency distribution would change under non-stationary conditions. The L-moments algorithm, Monte Carlo Simulation technique, and the magnitude of the trend calculated by Innovative Trend Analysis (ITA) were involved in scrutinizing the impact of non-stationary conditions on frequency analysis of annual maximum daily rainfall data sets. By including the own time-dependent change (trend) of each data in synthetic data, synthetically produced rainfall data was intended to reflect the actual conditions effectively. The simulated data has increased the heterogeneity of the entire region compared to the observed data and led to considerable differences in regional and site-based quantile estimates, and this difference became a nonlinear increase, especially after the 90% probability level. Based on this study, by considering stations with longer and equal or nearly equal observation periods in alternative regions, the change of frequency distribution behaviour in non-stationary conditions can be scrutinized with different methodologies.
Effects of crown retrieval on implants and the surrounding bone: a finite element analysis
Serhat Emre Ozkir,Server Mutluay Unal,Emel Yurekli,Sedat Güven 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.2
PURPOSE The aim of this study was to observe stress concentration in the implant, the surrounding bone, and other components under the pull-out force during the crown removal. MATERIALS AND METHODS Two 3-dimensional models of implant-supported conventional metal ceramic crowns were digitally constructed. One model was designed as a vertically placed implant (3.7 mm × 10 mm) with a straight abutment, and the other model was designed as a 30-degree inclined implant (3.7 mm × 10 mm) with an angled abutment. A pull-out force of 40 N was applied to the crown. The stress values were calculated within the dental implant, the abutment, the abutment screw, and the surrounding bone. RESULTS The highest stress concentration was observed at the coronal portion of the straight implant (9.29 MPa). The stress concentrations at the cortical bone were lower than at the implants, and maximum stress concentration in bone structure was 1.73 MPa. At the abutment screws, the stress concentration levels were similiar (3.09 MPa and 3.44 MPa), but the localizations were different. The stress at the angled abutment was higher than the stress at the straight abutment. CONCLUSION The pull-out force, applied during a crown removal, did not show an evident effect in bone structure. The higher stress concentrations were mostly observed at the implant and the abutment collar. In addition, the abutment screw, which is the weakest part of an implant system, also showed stress concentrations. Implant angulation affected the stress concentration levels and localizations. CLINICAL IMPLICATIONS These results will help clinicians understand the mechanical behavior of cement-retained implant-supported crowns during crown retrieval.
On interpolation functions of the twisted generalized Frobenius-Euler numbers
Y. Simsek,V. Kurt,O. Yurekli 장전수학회 2007 Advanced Studies in Contemporary Mathematics Vol.15 No.2
The main purpose of this paper is to apply Mellin transform to the generating functions of q-generalized Frobenius-Euler numbers and twisted q-generalized Frobenius-Euler numbers. By using this result, we define integral representation of twisted lH;q-function, which interpolates twisted q-generalized Frobenius- Euler numbers at negative integers. We also define twisted q-zeta functions. Furthermore, we give relation between twisted lH;q-functions and twisted q-zeta functions. We obtain new results related to the twisted lH;q-function, as well.
John W. Yurek,Nikki A. Doerr,Alex Tang,Adam S. Kohring,Frank A. Liporace,Richard S. Yoon 대한고관절학회 2023 Hip and Pelvis Vol.35 No.3
Purpose: This study aims to determine which intertrochanteric (IT) hip fracture and patient characteristics predict the necessity for adjunct reduction aides prior to prep and drape aiming for a more efficient surgery. Materials and Methods: Institutional fracture registries from two academic medical centers from 2017-2022 were analyzed. Data on patient demographics, comorbidities, fracture patterns identified on radiographs including displacement of the lesser trochanter (LT), thin lateral wall (LW), reverse obliquity (RO), subtrochanteric extension (STE), and number of fracture parts were collected, and the need for additional aides following traction on fracture table were collected. Fractures were classified using the AO/OTA classification. Regression analyses identified significant risk factors for needing extra reduction aides. Results: Of the 166 patients included, the average age was 80.84±12.7 years and BMI was 24.37±5.3 kg/m2. Univariate regression revealed increased irreducibility risk associated with RO (odds ratio [OR] 27.917, P≤0.001), LW (OR 24.882, P<0.001), and STE (OR 5.255, P=0.005). Multivariate analysis significantly correlated RO (OR 120.74, P<0.001) and thin LW (OR 131.14, P<0.001) with increased risk. However, STE (P=0.36) and LT displacement (P=0.77) weren’t significant. Fracture types 2.2, 3.2, and 3.3 displayed elevated risk (P<0.001), while no other factors increased risk. Conclusion: Elderly patients with IT fractures with RO and/or thin LW are at higher risk of irreducibility, necessitating adjunct reduction aides. Other parameters showed no significant association, suggesting most fracture patterns can be achieved with traction manipulation alone.
Mason D. Vialonga,Luke G. Menken,Alex Tang,John W. Yurek,Li Sun,John J. Feldman,Frank A. Liporace,Richard S. Yoon 대한고관절학회 2022 Hip and Pelvis Vol.34 No.1
Purpose: Mortality rates following hip fracture surgery have been well-studied. This study was conducted to examine mortality rates in asymptomatic patients presenting for treatment of acute hip fractures with concurrent positive COVID-19(+) tests compared to those with negative COVID-19(–) tests. Materials and Methods: A total of 149 consecutive patients undergoing hip fracture surgery during the COVID-19 pandemic at two academic medical centers were reviewed retrospectively. Patients were divided into two groups for comparative analysis: one group included asymptomatic patients with COVID-19+ tests versus COVID-19– tests. The primary outcome was mortality at 30-days and 90-days. Results: COVID-19+ patients had a higher mortality rate than COVID-19– patients at 30-days (26.7% vs 6.0%, P=0.005) and 90-days (41.7% vs 17.2%, P=0.046) and trended towards an increased length of hospital stay (10.1 ±6.2 vs 6.8±3.8 days, P=0.06). COVID-19+ patients had more pre-existing respiratory disease (46.7% vs 11.2%, P=0.0002). Results of a Cox regression analysis showed an increased risk of mortality at 30-days and 90- days from COVID-19+ status alone without an increased risk of death in patients with pre-existing chronic respiratory disease. Conclusion: Factors including time to surgery, age, preexisting comorbidities, and postoperative ambulatory status have been proven to affect mortality and complications in hip fracture patients; however, a positive COVID19 test result adds another variable to this process. Implementation of protocols that will promote prompt orthogeriatric assessments, expedite patient transfer, limit operating room traffic, and optimize anesthesia time can preserve the standard of care in this unique patient population.