Zonguldak Karaelmas University

About: Zonguldak Karaelmas University is a based out in . It is known for research contribution in the topics: Population & Copolymer. The organization has 1939 authors who have published 4296 publications receiving 62466 citations.

Effects of acute carbon monoxide poisoning on the P-wave and QT interval dispersions.

Abstract: OBJECTIVE: The aim of our study was to investigate atrial conduction and ventricular repolarization inhomogeneities using P-wave dispersion (Pwd) and QT dispersion (QTd) analyses in acute carbon monoxide (CO) poisoning. METHODS: Sixty patients were retrospectively included in this case-controlled study. Thirty acute CO poisoning patients were assigned to the Group with acute CO poisoning (ACOP). Patients who did not have acute CO poisoning were assigned to the control group (Group C, n=30). Anthropometric measurement, body mass index, electrocardiogram (ECG) and serum electrolyte levels were recorded in all patients. Also, carboxyhemoglobin (COHb) levels were recorded in Group ACOP. Pwd, QT interval and QTd durations were measured. Corrected QT (QTc) and QTc dispersion (QTcd) intervals were determined with the Bazett formula. Independent samples t and Chi-square tests were used for statistical analysis. RESULTS: No statistically significant difference was found between the age, gender distribution, anthropometric measurement, serum electrolytes, PR and QT durations between the groups. The Pwd (56.33±17.11 msec vs 28.33±11.16 msec, p=0.001) and QTd (63.33±26.69 msec vs 42.16±7.84 msec, p=0.001) were significantly longer in Group ACOP than in Group C. In addition, QTc and QTcd durations of Group ACOP were also found to be significantly longer than in Group C (p=0.001). CONCLUSION: In our study, we found in ECG analyses of patients with acute CO poisoning that the Pwd, QTc and QTcd durations were significantly prolonged when compared with control group. For this reason, patients with acute CO poisoning need close attention because of arrhythmias, which can be related to increased QTcd and Pwd durations. Language: en

Effects of simulated gastric juice on color stability, surface roughness and microhardness of laboratory-processed composites.

Abstract: Medical problems such as gastroesophageal reflux disease can cause considerable damage to restorations in the oral environment. This study evaluated the effects of gastric juice on the surface characteristics of different types of laboratory-processed indirect composites with different filler particles and polymerization modes. Specimens were prepared from Tescera (TES; Bisco), Sinfony (SIN; 3M ESPE), Solidex (SOL; Shofu), and Adoro (AD; Ivoclar Vivadent). Before exposing the specimens to simulated gastric juice for 24 h, color, surface roughness, and microhardness were measured on one half of the polished flat surface of each specimen. After exposure to the simulated gastric juice, the same tests were repeated on the other half of specimen surface. Results indicated that gastric juice had a significant impact on color change (p 0.05).

Synthesis of microbial elastomers based on soybean oil. Autoxidation kinetics, thermal and mechanical properties

Abstract: Microbial bioelastomers prepared by the autoxidation of the unsaturated medium-long chain length co-poly-3-hydroxyalkanoate’s (mlcl-PHAs) based on soybean oily acids (Sy) have been reported. Pseudomonas oleovorans were grown on a series of the mixture of octanoic acid (OA) and Sy with the weight ratio of 20:80, 28:72 and 50:50 in order to obtain unsaturated mlcl-copolyesters coded PHO-Sy-2080, PHO-Sy-2872, and PHO-Sy-5050, respectively. The microorganism was also grown on the mixture of Sy and 10-undecenoic acid (UA) with the weight ratio of 50:50 to obtain unsaturated copolyester coded PHU-Sy-5050. The PHAs obtained were characterized by 1H NMR and GC-MS techniques. Double bond contents of the unsaturated PHAs obtained were varying between 0.8 to 20 mol %. Autoxidation of the unsaturated copolyesters were carried out on exposure to air at room temperature in order to obtain new biomaterials whose mechanical strength was improved. Autoxidation kinetics, shelf life, mechanical and thermal properties of these biomaterials were evaluated.

The role of vitamin D in children with recurrent Tonsillopharyngitis

Abstract: The exact etiology of recurrent tonsillopharyngitis in children is not clear. Recurrent tonsillitis in children has multifactorial etiology like most of the diseases in childhood. In this study, our aim was to determine the potential role of vitamin D in recurrent tonsillitis by measuring serum 25-OH vitamin D levels and determining the vitamin D receptor polymorphism among children with recurrent tonsillitis. Eighty-four children with recurrent tonsillitis and seventy-one healthy children aging between 2 and 10 years were enrolled in this study. Serum 25-OH vitamin D level was measured with ELISA and vitamin D receptor gene polymorphism (Apa1, Taq 1, Fok1) was determined by PCR. Serum 25-OH vitamin D level below 50 nmol/L was accepted as deficiency. The vitamin D receptor gene polymorphism in each group was compared. The mean age was 5.6 ± 2.4 and 6.1 ± 2.7 years in study and control group, respectively. The average serum 25-OH vitamin D level was 142.7 ± 68.1 nmol/L in study group and 192.3 ± 56.1 nmol/L in control group. There was significant difference between the groups (p < 0.01). In study group, 4.7% (n = 4) of children had serum 25 OH vitamin D levels below 50 nmol/L. None of the children in control group had serum 25-OH vitamin D level below 50 nmol/L. There was no significant differences in vitamin D receptor gene polymorphisms between groups. Serum 25-OH vitamin D levels in recurrent tonsillitis group were lower than those in healthy children. But, there was no difference in the incidence of vitamin D receptor gene polymorphism between the two groups.

Investigation of power quality disturbances by using 2D discrete orthonormal S-transform, machine learning and multi-objective evolutionary algorithms

Abstract: The aim of this paper is to investigate the power quality analysis by using 2D discrete orthonormal S-transform, machine learning and multi-objective evolutionary algorithms. The fact that PQ signals are one-dimensional (1D) signals due to their nature leads to the search for feature extraction approaches based on 1D signal processing methods. Due to the electric network is getting more and more complicated day by day, it is necessary to determine effectively the disturbances events. In the proposed method, extraction of a new feature based on two-dimensional (2D) signal processing by 2D Fast Discrete Orthonormal Stockwell Transform (2D-FDOST) method and determination of the most suitable feature group by Non-dominated Sorting Genetic Algorithm II (NSGA-II) method are performed. Eleven different PQ events are synthetically produced based on mathematical modelling. 1D signals are transformed into 2D signals with equal row and column numbers. Statistical and image-based features are created on the amplitude and phase matrices obtained by 2D-FDOST method from 2D signals. The NSGA-II method, which is one of the multi-objective evolutionary optimization methods, is used to convert a large number of feature vectors into a small number of useful feature groups. NSGA-II produces the optimal solution for two different fitness functions that calculate the number of features and classifier performance. By using different machine learning classifiers for selected features, a model classifying PQ disturbances with high performance and robust structure against noisy situations is created.