Browsing by Author "Korkmaz A."

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    Prognostic value of serum pregnancy-associated plasma protein A level at the initial ED presentation in elderly patients with CAP
    (W.B. Saunders, 2015) Golcuk Y.; Golcuk B.; Bilge A.; Korkmaz A.; Irik M.; Hayran M.; Ozdemir A.T.; Kurtulmus Y.
    Objective This study aims to compare serum pregnancy-associated plasma protein A (PAPP-A) levels in surviving and nonsurviving elderly patients with community-acquired pneumonia (CAP), investigating whether PAPP-A is correlated with CAP prediction scores and whether PAPP-A can successfully predict 28-day mortality rates in elderly patients. Methods This prospective, observational, single-center, cross-sectional study was conducted at the emergency department (ED) of Celal Bayar University Hospital in Manisa, Turkey, between January and September 2014. All patients underwent follow-up evaluations 28 days after admission. The end point was defined as all-cause mortality. Results A total of 100 elderly patients (mean age, 77.3 ± 7.6 years [range, 65-94 years]); 60% men) with CAP were enrolled in this study. All-cause mortality at the 28-day follow-up evaluation was 22%. Admission PAPP-A levels were significantly higher in nonsurvivors compared with 28-day survivors (10.3 ± 4.5 vs 3.8 ± 2.6 ng/mL, P <.001). A significant and positive correlation between admission PAPP-A levels and pneumonia severity index; confusion, oxygen saturation, respiratory rate, blood pressure, and age 75 years or older; and confusion, urea, respiratory rate, blood pressure, and age older than 65 years scores was found (r =.440, P <.001; r =.395, P <.001; and r =.359, P <.001, respectively). Moreover, we determined that the optimal PAPP-A cutoff for predicting 28-day mortality at the time of ED admission was 5.1 ng/mL, with 77.3% sensitivity and 77.9% specificity. Conclusions Serum PAPP-A level is valuable for predicting mortality and the severity of the disease among elderly patients with CAP at ED admission. Thus, PAPP-A might play a further role in the clinical assessment of the severity of CAP. © 2015 Elsevier Inc.
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    Outcome of the Respiratory Syncytial Virus related acute lower respiratory tract infection among hospitalized newborns: A prospective multicenter study
    (Taylor and Francis Ltd, 2016) Alan S.; Erdeve O.; Cakir U.; Akduman H.; Zenciroglu A.; Akcakus M.; Tunc T.; Gokmen Z.; Ates C.; Atasay B.; Arsan S.; Anik A.; Turkmen M.K.; Erdogan Y.; Oygur N.; Kahvecioglu D.; Yildiz D.; Caner I.; Tekgunduz K.S.; Kurt A.; Yigit Y.; Bilgili G.; Bolat F.; Cevit O.; Ozlu F.; Satar M.; Ertugrul S.; Cakir B.; Unal S.; Iscan B.; Duman N.; Ergor S.N.; Yalaz M.; Celik I.; Celik U.; Hirfanoglu I.M.; Koc E.; Sivasli E.; Melekoglu N.A.; Kiray Bas E.; Bozkaya D.; Korkmaz A.; Ozdemir R.; Karadag A.; Ozer E.; Ilhan O.; Mutlu M.; Aslan Y.; Erener- Ercan T.; Cetinkaya M.; Sahin O.; Akin M.A.; Okumus N.; Demirel G.; Kilic A.; Turkoglu-Unal E.; Bulbul A.; Takci S.; Anuk-Ince D.; Ciftdemir N.A.; Acunas B.; Ozkan H.; Koksal N.; Okulu E.; Demir N.; Tuncer O.; Dizdar E.A.; Oguz S.; Dilmen U.
    Aim: To determine the incidence and outcomes of respiratory syncytial virus (RSV)-related acute lower respiratory tract infection (ALRI) including morbidity, nosocomial infection and mortality among newborn infants who were admitted to the neonatal intensive care units (NICUs).Methods: A multicenter, prospective study was conducted in newborns who were hospitalized with community acquired or nosocomial RSV infection in 44 NICUs throughout Turkey. Newborns with ALRI were screened for RSV infection by Respi-Strip®-test. Main outcome measures were the incidence of RSV-associated admissions in the NICUs and morbidity, mortality and epidemics results related to these admissions.Findings: The incidence of RSV infection was 1.24% (n: 250) and RSV infection constituted 19.6% of all ALRI hospitalizations, 226 newborns (90.4%) had community-acquired whereas 24 (9.6%) patients had nosocomial RSV infection in the NICUs. Of the 250 newborns, 171 (68.4%) were full-term infants, 183 (73.2%) had a BW >2500 g. RSV-related mortality rate was 1.2%. Four NICUs reported seven outbreaks on different months, which could be eliminated by palivizumab prophylaxis in one NICU.Conclusion: RSV-associated ALRI both in preterm and term infants accounts an important percent of hospitalizations in the season, and may threat other high-risk patients in the NICU. © 2015 Taylor & Francis.
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    Microstructural and mechanical characterization of powder-pack boronized Incoloy A286 superalloy
    (IOP Publishing Ltd, 2021) Türkmen İ.; Korkmaz A.
    In this study, Incoloy A286 superalloy were boronized successfully by powder-pack boronizing process at 850 °C, 900 °C and 950 °C for 4 h by using a boronizing powder mixture containing H3BO3 as boron source. The thickness and morphology of the boride layer was identified by microstructural examinations. The boride layer with complex, compact and smooth morphology was formed on the surface of the samples. As a result of XRD analyses, it was determined that the compact boride layer was formed many phases such as FeB, Fe2B, Fe3B, CrB and Ni4B3 etc. It was specified that the average hardness value of the boride layer was approximately between 2400 and 3000 HV by microhardness tests. Also the graphs of friction coefficient and values of the specific wear rate were obtained by performing ball on disk wear tests. It was identified that the specific wear rate of boronized samples was approximately 9.5 times lower than that of unboronized samples. © 2021 IOP Publishing Ltd
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    Effect of chip amount on microstructural and mechanical properties of a356 aluminum casting alloy
    (Polska Akademia Nauk, 2021) Kaya A.Y.; Ozaydin O.; Yagci T.; Korkmaz A.; Armakan E.; Culha O.
    Aluminum casting alloys are widely used in especially automotive, aerospace, and other industrial applications due to providing desired mechanical characteristics and their high specific strength properties. Along with the increase of application areas, the importance of recycling in aluminum alloys is also increasing. The amount of energy required for producing primary ingots is about ten times the amount of energy required for the production of recycled ingots. The large energy savings achieved by using the recycled ingots results in a significant reduction in the amount of greenhouse gas released to nature compared to primary ingot production. Production can be made by adding a certain amount of recycled ingot to the primary ingot so that the desired mechanical properties remain within the boundary conditions. In this study, by using the A356 alloy and chips with five different quantities (100% primary ingots, 30% recycled ingots + 70% primary ingots, 50% recycled ingots + 50% primary ingots, 70% recycled ingots + 30% primary ingots, 100% recycled ingots), the effect on mechanical properties has been examined and the maximum amount of chips that can be used in production has been determined. T6 heat treatment was applied to the samples obtained by the gravity casting method and the mechanical properties were compared depending on the amount of chips. Besides, microstructural examinations were carried out with optical microscopy techniques. As a result, it has been observed that while producing from primary ingots, adding 30% recycled ingot to the alloy composition improves the mechanical properties of the alloy such as yield strength and tensile strength to a certain extent. However, generally a downward pattern was observed with increasing recycled ingot amount. © 2021 Polish Academy of Sciences. All rights reserved.
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    Optimization of T6 Heat Treatments for AlSi5Mgx Alloys via Computational Materials Engineering and Experimental Validation for Automotive Applications
    (Springer, 2024) Korkmaz A.; Yağcı T.; Çulha O.
    In this study, T6 heat treatments were applied to AlSi5Mgx (x: 0.3, 0.5, 0.7 wt.%) alloys, fabricated through the low pressure die casting technique. Optimization of these treatments was conducted utilizing computational materials engineering (CME) methodologies, simulation techniques, and design of experiment studies. The objective is to position the investigated alloys as potential substitutes for the heat-treated AlSi7Mg0.3 alloy commonly employed within the automotive sector, with a focus on enhancing microstructural and mechanical characteristics. A comparative analysis was conducted between virtual and empirical data through laboratory-scale experimental investigations. Utilizing the Taguchi experimental design methodology, heat treatments were administered to the spoke region of the wheels, employing three distinct parameters: solution treatment, aging temperature, and time. The analysis outcomes underwent assessment employing the Taguchi method, analysis of variance, and regression analyses, facilitating an exploration into the effects of heat treatment conditions on the physical and mechanical attributes of the alloys. The AlSi5Mg0.5 alloy exhibited optimal mechanical properties when subjected to a solution treatment temperature of 550 °C, an aging temperature of 180 °C, and an aging time of 4 h. Furthermore, a notable similarity was observed between the analysis outcomes derived from CME methodologies and experimental studies. This concurrence lends credence to the accuracy and reliability of the employed software. © ASM International 2024.