Showing papers by "Zonguldak Karaelmas University published in 2013"
TL;DR: The results suggest that the combination of colistin with rifampicin may improve clinical and microbiological outcomes of VAP patients infected with A. baumannii.
Abstract: The aim of this study was to compare the responses of colistin treatment alone vs. a combination of colistin and rifampicin in the treatment of ventilator-associated pneumonia (VAP) caused by a carbapenem-resistant A. baumannii strain. Forty-three patients were randomly assigned to one of two treatment groups. Although clinical (P = 0·654), laboratory (P = 0·645), radiological (P = 0·290) and microbiological (P = 0·597) response rates were better in the combination group, these differences were not significant. However, time to microbiological clearance (3·1 ± 0·5 days, P = 0·029) was significantly shorter in the combination group. The VAP-related mortality rates were 63·6% (14/22) and 38·1% (8/21) for the colistin and the combination groups (P = 0·171), respectively. Our results suggest that the combination of colistin with rifampicin may improve clinical and microbiological outcomes of VAP patients infected with A. baumannii.
177 citations
TL;DR: In this paper, the authors investigated the behavior of rock mass subjected to blasting load using three dimensional finite difference numerical modeling and found that the most efficient explosive in rock blasting will be the one with low frequency content but with a sufficiently high borehole wall pressure.
158 citations
TL;DR: The ProTaper group produced the highest mean extrusion value and the Reciproc produced less debris compared with all the other instruments (P > .05).
150 citations
TL;DR: It is demonstrated that the average degree of neurons within the hybrid scale-free network significantly influences the optimal amount of noise for the occurrence of stochastic resonance, indicating that there also exists an optimal topology for the amplification of the response to the weak input signal.
Abstract: We study the phenomenon of stochastic resonance in a system of coupled neurons that are globally excited by a weak periodic input signal. We make the realistic assumption that the chemical and electrical synapses interact in the same neuronal network, hence constituting a hybrid network. By considering a hybrid coupling scheme embedded in the scale-free topology, we show that the electrical synapses are more efficient than chemical synapses in promoting the best correlation between the weak input signal and the response of the system. We also demonstrate that the average degree of neurons within the hybrid scale-free network significantly influences the optimal amount of noise for the occurrence of stochastic resonance, indicating that there also exists an optimal topology for the amplification of the response to the weak input signal. Lastly, we verify that the presented results are robust to variations of the system size.
106 citations
TL;DR: In this paper, a new subsidence prediction approach (ISP-Tech) is proposed, which takes into account the most important parameters contributing subsidence development such as coal production methods, depth, mining sequence and other geomechanical characteristics of underground rock strata, etc.
94 citations
TL;DR: In this paper, the authors constructed a financial stress index for Bulgaria, Czech Republic, Hungary, Poland, and Russia and examined the relationship between financial stress and economic activity, finding that there is a significant relationship between stress and some measures of economic activity.
85 citations
TL;DR: In this article, the authors studied the negotiation of identity, context, and practice of a beginning science teacher in the first year of teaching and found that conflicts in identities, institutional expectations, and personal dispositions of this novice influenced his transition in becoming a member of his school community.
Abstract: The demanding first years of teaching are a time when many teachers leave the teaching profession or discard the reform-minded practice emphasized in teacher preparation. If we are to lessen teacher attrition and more effectively support teachers during their development, a better understanding of what occurs during their induction into the profession is needed. The question that drove this research was what factors influence how a beginning science teacher negotiates entry into teaching? Specifically, we sought to understand how a beginning science teacher’s identities interact with the teaching context; how this interaction shapes his use of reform-minded teaching practice; and how the negotiation of identity, context, and practice influence a novice teacher’s employment decisions. The study involved 2 years of data collection; data included classroom and school observations, questionnaires, interviews, and teaching artifacts (such as lesson plans and assessments). The results demonstrate how conflicts in identities, institutional expectations, and personal dispositions of this novice influenced his transition in becoming a member of his school community. Implications of these interactions for teacher preparation and support are provided.
78 citations
TL;DR: The different roles played by parental rejection and parental warmth in the development of adolescents' emotion regulation accord with arguments that socialization occurs in different domains and that rejection and warmth are not aspects of the same domain.
78 citations
Journal Article•
TL;DR: In this paper, the authors created a problem solving based learning environment to enhance the students' problem-solving skills, which is recognized as an important life skill involving a range of processes including analyzing, interpreting, reasoning, predicting, evaluating and reflecting.
Abstract: Problem solving is recognized as an important life skill involving a range of processes including analyzing, interpreting, reasoning, predicting, evaluating and reflecting. For that reason educating students as efficient problem solvers is an important role of mathematics education. Problem solving skill is the centre of mathematics curriculum. Students' gaining of that skill in school mathematics is closely related with the learning environment to be formed and the roles given to the students. The aim of this study is to create a problem solving based learning environment to enhance the students' problem solving skill. Within this scope, students' practiced activities and problems that provide them to proceed in Polya (1945)'s problem solving phases and throughout the study, students' success in problem solving have been evaluated. While experimental group students received problem solving based learning environment performed, control group students have continued their present program in this quise1experimental study. Eleven problem solving activities were given to the students at the beginning, middle and end of the study and the students' performances were analyzed based on problem solving phases. The findings illustrated that the experimental group students' success in problem solving activities has increased while the control group students' success has not changed significantly.
72 citations
TL;DR: Electrocoagulation of textile wastewater using a uniquely designed reactor was very effective and direct dischargeable effluent, complying with legal requirements, was obtained and maghemite is the main by-product formed after EC.
71 citations
TL;DR: In this paper, the authors examined the relationship between drilling rate index (DRI) and some mechanical properties of rocks in order to evaluate the effect of strength and indexes of rock on rock drillability.
TL;DR: Chitosan scaffold that was called GEL could be an appropriate carrier for PRP applications by providing sustained release of GFs and it was demonstrated that there is no deterioration on the scaffolds porous, 3D, and interconnected structure.
Abstract: The aim of this study is to compare the effects of different platelet-rich plasma (PRP) preparation methods on platelet activity and to investigate the growth factor (GF) release kinetics from PRP-loaded chitosan scaffolds for tissue engineering applications. Flow cytometry analysis showed that centrifugation processes used for PRP preparation did not cause significant effect on platelet activation levels by means of markers investigated. Two different methods were used to prepare PRP-loaded chitosan scaffolds: (i) PRP was added to chitosan gel before freeze-drying to prepare scaffolds called as “GEL” and (ii) PRP was embedded to freeze-dried chitosan scaffolds to prepare scaffolds called as “SPONGE.” In addition, nonactivated PRP and PRP activated with type-I collagen were used as control groups. Scanning electron microscopy images demonstrated that, in GEL group, there is no deterioration on the scaffolds porous, 3D, and interconnected structure. GF release kinetics was determined by enzyme-linked immunosorbent assay for platelet-derived GF-BB, transforming GF-β1, and insulin-like GF-1. A sustained release of GFs was achieved in GEL group while a sharp burst release was observed for all the GFs from the SPONGE groups. Moreover, platelet-derived GF-BB, insulin-like GF-1, and transforming GF-β1 releases were prolonged to 20 days in GEL groups, and the biological activities of all GFs released from GEL and SPONGE scaffolds were preserved. This study demonstrated that chitosan scaffold that was called GEL could be an appropriate carrier for PRP applications by providing sustained release of GFs. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 28–35, 2013.
TL;DR: Regular and systematic exercise regimens implemented by children with ALL have resulted in improved testing results, enhanced physical performance, and better laboratory results compared with a control group and to children's scores before the initiation of such a program.
Abstract: This randomized, controlled experimental study was carried out to determine the effects of an exercise program on both physical parameters and the quality of life of children with acute lymphoblastic leukemia (ALL). A total of 41 children with ALL (20 trial and 21 control cases) at two university hospitals were accepted into the study. Due to the demise of one of the children in the trial group, the study was completed with 19 trial and 21 control patients, a total of 40 children and their parents. Regular and systematic exercise regimens implemented by children with ALL have resulted in improved testing results, enhanced physical performance, and better laboratory results compared with a control group and to children's scores before the initiation of such a program.
TL;DR: In this article, the authors examined episodes of financial stress and developed a financial stress index for the Turkish economy for the 1997-2010 period and showed that financial stress affects economic activity significantly.
TL;DR: Although one of the empirical potentials is found to favour the LT structure, it is shown that Marks Decahedral and mixed FCC-HCP motifs are lowest in energy at the DFT level.
Abstract: The energetics, structures and segregation of 98-atom AuPd nanoclusters are investigated using a genetic algorithm global optimization technique with the Gupta empirical potential (comparing three different potential parameterisations) followed by local minimizations using Density Functional Theory (DFT) calculations A shell optimization program algorithm is employed in order to study the energetics of the highly symmetric Leary Tetrahedron (LT) structure and optimization of the chemical ordering of a number of structural motifs is carried out using the Basin Hopping Monte Carlo approach Although one of the empirical potentials is found to favour the LT structure, it is shown that Marks Decahedral and mixed FCC-HCP motifs are lowest in energy at the DFT level
TL;DR: In this paper, a one-step synthesis of block-graft copolymers by reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) by using a novel initiator was reported.
Abstract: One-step synthesis of block-graft copolymers by reversible addition-fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) by using a novel initiator was reported. Block-graft copolymers were synthesized in one-step by simultaneous RAFT polymerization of n-butylmethacrylate (nBMA) and ROP of e-caprolacton (CL) in the presence of a novel macroinitiator (RAFT-ROP agent). For this purpose, first epichlorohydrin (EPCH) was polymerized by using H2SO4 via cationic ring-opening mechanism. And then a novel RAFT-ROP agent was synthesized by the reaction of potassium ethyl xanthogenate and polyepichlorohydrin (poly-EPCH). By using the RAFT-ROP agent, poly[CL-b-EPCH-b-CL-(g-nBMA)] block-graft copolymers were synthesized. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one-step polymerization reaction were evaluated. The block lengths of the block-graft copolymers were calculated by using 1H-nuclear magnetic resonance (1H NMR) spectrum. The block length could be adjusted by varying the monomer and initiator concentrations. The characterization of the products was achieved using 1H NMR, Fourier-transform infrared spectroscopy, gel-permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, elemental analysis, and fractional precipitation (γ) techniques. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2651–2659
TL;DR: Vitamin D does not seem to be effective on histological findings although it has some beneficial effects via RAS system and a promising effect on antioxidant system.
Abstract: Introduction. Acute kidney injury (AKI) pathogenesis is complex. Findings of gentamicin nephrotoxicity are seen in 30% of the AKI patients. Vitamin D has proven to be effective on renin expression, inflammatory response, oxidative stress, apoptosis, and atherosclerosis. We aimed to investigate the effect of vitamin D in an experimental rat model of gentamicin-induced AKI. Methods. Thirty nonuremic Wistar albino rats were divided into 3 groups: Control group, 1 mL saline intramuscular (im) daily; Genta group, gentamicin 100 mg/kg/day (im); Genta + vitamin D, gentamicin 100 mg/kg/day (im) in addition to 1α, 25 (OH)2D3 0.4 mcg/kg/day subcutaneously for 8 days. Blood pressures and 24-hour urine were measured. Blood urea and creatinine levels and urine tubular injury markers were measured. Renal histology was semiquantitatively assessed. Results. Urea, creatinine and urine neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 were all increased in Genta group indicating AKI model. Systolic blood pressure decreased, but urine volume and glutathione increased in Genta + Vit D group compared to Control group. Histological scores indicating tubular injury increased in Genta and Genta + Vit D groups. Conclusions. Vitamin D does not seem to be effective on histological findings although it has some beneficial effects via RAS system and a promising effect on antioxidant system.
TL;DR: In this paper, the tip shape of a blind micro-hole produced using micro electrical discharge machining varies with respect to the process parameters used during machining, and the origin of such tip deformation in micro electric discharge machined of blind microhole was investigated.
Abstract: The tip shape of a blind micro-hole produced using micro electrical discharge machining varies with respect to the process parameters used during machining. The usual tip shape is a blunt geometry within the common range of applications, however, under specific machining conditions and machining depths, the tip shape changes drastically to an inverted concaved shape. The origin of such tip deformation in micro electric discharge machining of blind micro-holes was investigated. It was observed that debris particles produced during machining accumulated at the tip, formed a hill and functioned as a tool electrode especially when using fine machining conditions. The phenomena is elaborated experimentally with the affecting parameters to describe the wear mechanism. Open gap voltage, pulse energy and tool rotation speed are examined as varying parameters during the experiments.
TL;DR: A-ADHD is a frequent comorbidity in BMD and is associated with early starting age of BMD, higher number of manic episodes during the course of B MD, and more comorbrid Axis I diagnoses.
TL;DR: With the use of arthroscopically assisted techniques in fixation of isolated medial malleolar fractures, surgeon can evaluate intra-articular surface and reduction that may be of value in the improvement in clinical outcomes over conventional surgical treatment.
Abstract: Purpose of this case–control study was to evaluate the feasibility and advantages of arthroscopically assisted reduction and internal fixation of isolated medial malleolar fractures and compare the outcomes with conventional open reduction and internal fixation. Forty-seven patients with medial malleolar fractures were grouped into two: arthroscopy-assisted group, and conventional open reduction and internal fixation group. Arthroscopic treatment group consisted of 21 patients. The mean age was 34 years (range: 22–49 years). Conventional open reduction and internal fixation group included 26 patients. The mean age was 42 years (range: 22–58 years). According to Herscovici system, 6 fractures in the arthroscopy group were classified as type-B, 13 fractures as type-C, and 2 fractures were classified as type-D. In both groups, fractures were classified according to Herscovici system. Radiological and clinical outcomes were evaluated according to van Dijk classification and Olerud–Molander scoring system, respectively. The mean follow-up period was 26 months (18–52 months) for arthroscopically assisted group and 38 months (24–58 months) for the conventional group. According to van Dijk classification, there was only one patient with Grade 1 osteoarthritic changes in arthroscopically assisted group compared with the conventional group where two patients had Grade 2 and one patient had Grade 1 osteoarthritic changes. Median Olerud Scores were 92.3 (75–100) and 86.3 (70–100) for the arthroscopically assisted group and for the conventional group, respectively. The difference was statistically significant (p = 0.015). With the use of arthroscopically assisted techniques in fixation of isolated medial malleolar fractures, surgeon can evaluate intra-articular surface and reduction that may be of value in the improvement in clinical outcomes over conventional surgical treatment. Case–control study, Level III.
TL;DR: The mechanism that underlies inverse stochastic resonance is clarified and it is shown that its most surprising features are a consequence of the dynamical structure of the model.
Abstract: M.U. acknowledges support from Grant No. 13643-49840 from the Turkish Council of Higher Education (YOK) and the hospitality of the Krasnow Institute for Advanced Study at George Mason University. Publication of this article was funded in part by the George Mason University Libraries Open Access Publishing Fund and Bulent Ecevit University.
TL;DR: Data obtained from this study indicated that ozone could increase the endogenous antioxidant defense mechanism in rats and there by protect the animals from radiation-induced organ toxicity.
Abstract: Because radiation-induced cellular damage is attributed primarily to harmful effects of free radicals, molecules with direct free radical scavenging properties are particularly promising as radioprotectors. It has been demonstrated that controlled ozone administration may promote an adaptation to oxidative stress, preventing the damage induced by reactive oxygen species. Thus, we hypothesized that ozone would ameliorate oxidative damage caused by total body irradiation (TBI) with a single dose of 6 Gy in rat liver and ileum tissues. Rats were randomly divided into groups as follows: control group; saline-treated and irradiated (IR) groups; and ozone oxidative preconditioning (OOP) and IR groups. Animals were exposed to TBI after a 5-day intraperitoneal pretreatment with either saline or ozone (1 mg/kg/day). They were decapitated at either 6 h or 72 h after TBI. Plasma, liver and ileum samples were obtained. Serum AST, ALT and TNF-α levels were elevated in the IR groups compared with the control group and were decreased after treatment with OOP. TBI resulted in a significant increase in the levels of MDA in the liver and ileal tissues and a decrease of SOD activities. The results demonstrated that the levels of MDA liver and ileal tissues in irradiated rats that were pretreated with ozone were significantly decreased, while SOD activities were significantly increased. OOP reversed all histopathological alterations induced by irradiation. In conclusion, data obtained from this study indicated that ozone could increase the endogenous antioxidant defense mechanism in rats and there by protect the animals from radiation-induced organ toxicity.
TL;DR: AIP was found to show a correlation with a greater number of risk factors, both classical and CKD specific, than CIMT, and the data suggest that AIP might be a method which can be used both in diagnosis of subclinical atherosclerosis and in deceleration processes of its progression.
Abstract: Incidence of cardiovascular diseases in the patients having chronic kidney disease (CKD) is between 25% and 60%. This increased rate is proposed to be associated with "accelerated atherosclerosis." Increased carotid intima-media thickness (CIMT) is a subclinical atherosclerosis marker. Small-dense low-density lipoprotein particles are a strong risk factor for atherosclerosis. It was shown that atherogenic index of plasma (AIP = log(TG/HDL-c)) is correlated with size of the lipoprotein particles. We investigated the correlation between AIP and CIMT which is a subclinical atherosclerosis marker, in hemodialysis (HD) patients. A total of 62 persons with 31 patients under HD therapy and 31 volunteers were included in the study. In all the participants, CIMT was measured and AIP were calculated. AIP and CIMT values of the participants were compared with blood pressures, lipid profiles and the other risk factors. AIP (0.39 ± 0.32) and CIMT (0.57 ± 0.13) were found significantly higher in the patient group than in the controls (0.04 ± 0.36 and 0.45 ± 0.119, respectively); (P = 0.0001 and 0.0001, respectively). There was a significant correlation between AIP and increased CIMT in the patient group (P = 0.0001, r = 0.430). Among the lipid parameters, the strongest correlation was found between CIMT and AIP. We demonstrated the significant increase of AIP and CIMT in HD patients. A correlation was found between AIP and CIMT. AIP was found to show a correlation with a greater number of risk factors, both classical and CKD specific, than CIMT. These data suggest that AIP might be a method which can be used both in diagnosis of subclinical atherosclerosis and in deceleration processes of its progression.
TL;DR: Using titanium or gold-palladium abutments for implant supported all ceramics will be esthetically questionable and white opaque cement will be helpful to mask the dark color of titanium abutment.
Abstract: Purpose. The purpose of this study is to evaluate the effects of different abutment materials and luting cements color on the final color of implant-supported all-ceramic restorations. Materials and methods. Ten A2 shade IPS e.max Press disc shape all-ceramic specimens were prepared (11 × 1.5 mm). Three different shades (translucent, universal and white opaque) of disc shape luting cement specimens were prepared (11 × 0.2 mm). Three different (zirconium, gold-palladium and titanium) implant abutments and one composite resin disc shape background specimen were prepared at 11 mm diameter and appropriate thicknesses. All ceramic specimens colors were measured with each background and luting cement samples on a teflon mold. A digital spectrophotometer used for measurements and data recorded as CIE L*a*b* color co-ordinates. An optical fluid applied on to the samples to provide a good optical connection and measurements on the composite resin background was saved as the control group. ΔE values were c...
TL;DR: This paper investigated the development of preservice teachers' knowledge base for science teaching on the rate of reaction topic within the 14-week content representation (CoRe)-based mentoring-enriched practicum course.
Abstract: The purpose of this research was twofold. The first was to investigate the development of preservice teachers’ knowledge base for science teaching on the rate of reaction topic within the 14-week content representation (CoRe)-based mentoring-enriched practicum course. In this course, CoRe design was used as a form of lesson planning and intensive educative mentoring was provided by teaching assistants. The second purpose was to identify which aspects of the practicum course contributed to preservice teachers’ development. Three preservice chemistry teachers voluntarily participated in the study. Qualitative data sources included CoRe, semistructured interviews, and reflection papers. Both inductive and deductive analyses were applied by triangulating findings from multiple data sources. Results revealed that at the end of the practicum, participants were able to successfully link content with teaching to promote student learning. Their pedagogical content knowledge (PCK) developed with its all components coherently integrated with each other. They also started to view the PCK construct as professional pedagogical knowledge. Educative mentoring with the use of an explicit and shared PCK language supported by CoRes, teaching experiences, and the observation of peers were reported as the most valuable aspects in stimulating teacher development. Implications for teachers’ professional growth and research are discussed.
TL;DR: In this paper, the authors used response surface methodology (RSM) to optimize the operating variables viz. current density (CD, A/m2), operating time (tEC, min) and arsenic concentration (Co, μg/L) on arsenic removal in the EC process using iron electrodes.
Abstract: In this investigation, arsenic removal from drinking water using electrocoagulation (EC) in a batch mode was studied by response surface methodology (RSM). The RSM was applied to optimize the operating variables viz. current density (CD, A/m2), operating time (tEC, min) and arsenic concentration (Co, μg/L) on arsenic removal in the EC process using iron electrodes. The combined effects of these variables were analyzed by the RSM using quadratic model for predicting the highest removal efficiency of arsenic from drinking water. The proposed model fitted very well with the experimental data. R2 adjusted correlation coefficients (AdjR2: 0.93) for arsenic removal efficiency showed a high significance of the model. The model predicted for a maximum removal of arsenic at the optimum operating conditions (112.3 μg/L, 5.64 A/m2 and 5 min) after the EC process was 93.86% which corresponded to effluent arsenic concentration of 6.9 μg/L. The minimum operating cost (OC) of the EC process was 0.0664 €/m3. This...
TL;DR: Results of this study suggest that the events leading to fetoplacental insufficiency lead to a reduction in the levels of estriol limit deposition of OxLDL in placental tissues and the serum PON1 activity is probably important in the inhibition of Ox LDL in preeclampsia.
Abstract: In vitro literature studies have suggested that atherosclerotic oxidized low density lipoprotein (OxLDL) inhibits trophoblast invasion. The objective of this study was to determine the levels of OxLDL and to examine the relationship between antioxidative estradiol, estriol, and prooxidative progestin in normal and preeclamptic placental tissues and measure the serum activity of antioxidative paraoxonase (PON1). The study included 30 preeclamptic and 32 normal pregnant women. OxLDL was determined with ELISA, estradiol, unconjugated estriol, and progesterone that were determined with chemiluminescence method in placental tissues. Serum PON1 activity was determined with spectrophotometric method. Levels of OxLDL (P = 0.027), estriol (P < 0.001), estradiol (P = 0.008), and progesterone (P = 0.009) were lower in the placental tissues of preeclamptic group compared to the normal pregnant women. Serum PON1 activity was higher in preeclamptic group (P = 0.040) and preeclamptic group without intrauterine growth restriction (P = 0.008) compared to normal pregnant women. Tissue estriol of preeclamptic group without/with IUGR (P < 0.001, P = 0.002) was lower than the normal group. Results of our study suggest that the events leading to fetoplacental insufficiency lead to a reduction in the levels of estriol limit deposition of OxLDL in placental tissues. The serum PON1 activity is probably important in the inhibition of OxLDL in preeclampsia.
TL;DR: In this article, a central composite experimental design was used to investigate experimental process conditions (extraction temperature, extraction time and biomass loading) for the supercritical ethanol extraction of bio-oils from German beech wood.
TL;DR: In this paper, the applicability of VAM mitigation and utilization options for an underground coal mine in Turkey was evaluated and a detailed preliminary economic analysis was performed for the technology alternatives proposed for the mine.
TL;DR: In this article, the authors evaluate the dust concentrations and quartz contents of respirable dusts in coal faces and pneumoconiosis risks related to face workers in Turkish coal mining collieries.