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Koleksiyondaki öğeler
- MakaleAçık Erişim2014Scopus SJRQ3Is the combined use of insulin resistance indices, Including adipokines, more reliable in metabolic syndrome?
Kural, Birgül; Değer, Orhan; Erem, Cihangir; Balaban Yücesan, Fulya; Aliyazicioğlu, Rezzan; Barlak, Yaşam
Background/aim: To determine the levels of adipokines (leptin, adiponectin, resistin, and visfatin) and the indices of insulin sensitivity/ resistance, and to examine the relationship among them in patients with metabolic syndrome (MetS).; Materials and methods: The study groups included 45 subjects with MetS (31 women/14 men), and 45 sex- and age-matched non-MetS healthy volunteers (31 women/14 men). The levels of adipokines were determined by enzyme-linked immunosorbent assay.; Results: The levels of leptin and visfatin were significantly higher in the MetS than in the non-MetS subjects (P < 0.01). There was no difference in adiponectin levels in subjects with and without MetS (P = 0.052). Similarly, resistin did not show any statistically significant difference. A statistically significant positive correlation of leptin with insulin levels was observed, while negative correlations of visfatin levels with age, and resistin levels with the ratio of adiponectin to leptin, were found in the MetS (P < 0.05). The combination of adipokines, insulin resistance-sensitivity parameters, and MetS criteria parameters gave more signifcant differences than a single parameter.; Conclusion: Since the parameters mentioned above might affect, interact with, and/or interfere with each other, the combinations of these parameters might give more reliable results to evaluate the insulin resistance/sensitivity in MetS patients.
AtıfScopus7WoS7OpenAlex8
İncele - BildiriYalnız künye2014Effects of discretization schemes on numerical results of natural convection heat transfer
Sahin, Birol
Two dimensional natural convection heat transfer in a square enclosure is numerically analyzed. Laminar naturalconvection heat transfer is studied by solving the Navier-Stokes and energy equations using finite volume method. Numerical solutions of flow field are obtained by Semi-Implicit Method for Pressure-Linked Equations (SIMPLE). Effects of the discretization schemes on numerical solutions are compared with each other.
- MakaleAçık Erişim2015Scopus SJRQ3Time dependent changing of dynamic characteristics of laboratory arch dam model
Altunişik, Ahmet Can; Sevİm, Barış; Bayraktar, Alemdar; Adanur, Süleyman; Günaydin, Murat
This paper investigates the time dependent changing of dynamic characteristics of laboratory arch dam models using ambient vibration test. For this aim, a prototype arch dam-reservoir-foundation model is constructed in laboratory conditions. The first experimental measurement tests are performed after the poured concrete aged for 10 months for some damage scenarios such as undamaged, minor-damaged and severely damaged of dam body in November 2009. To extract the experimental dynamic characteristics such as natural frequencies, mode shapes and damping ratios, a small impact effect is used as a source of ambient vibrations. Experimental measurements tests are repeated using same excitations considering severely damaged conditions with and without reservoir water in February 2014, and the dynamic characteristics are obtained, experimentally. Enhanced Frequency Domain Decomposition Method in the frequency domain is used to extract the experimental dynamic characteristics. At the end of the study, experimentally identified dynamic characteristics are compared with each other and time effects are investigated in detail. Maximum differences between the natural frequencies obtained as 15.36% and 14.38% in the third mode for empty and full reservoir conditions, respectively. It is thought that the increase of the natural frequencies is resulted from gaining of rigidity of the concrete, ageing, temperature and different environmental effects.
AtıfScopus6WoS5OpenAlex7İncele - MakaleYalnız künye2015Scopus SJRQ1Utilization of macaroni by-product as a new food ingredient: Powder of macaroni boiling water
Yuksel, Ferhat; Karaman, Kevser
In the present study, production and using possibilities of powder of macaroni boiling water (PMBW) were investigated. After cooking process of macaroni, firstly pre-drying was carried out at 50°C in a drying oven and then lyophilization process was conducted to obtain final powder product. Physicochemical characterizations like total dry matter, ash, fat, protein, pH, aw and color properties were carried out and also technological properties of sample were determined. Both macaroni boiling water and the final powder product were examined in terms of microbiological analyses. It was found that macaroni boiling water had to be processed in 6h after cooking if the cooking water was stored at room temperature. Also, the duration of 12h after cooking was found to be limit level for microbiological safety of cooking water if it was stored at+4°C. Besides, scanning electron micrographs of particles and fatty acid and mineral profile of the final powder product were determined. Macaroni boiling water is a by-product having a lot of nutrients and in this study it was proved that utilization of this by-product may be feasible. The macaroni boiling water can be used as a food ingredient and also as an enrichment agent.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2010Scopus SJRQ1Prognostic significance of perineural invasion in patients with gastric cancer who underwent curative resection
Bilici, Ahmet; Seker, Mesut; Ustaalioglu, Bala Basak Oven; Kefeli, Umut; Yildirim, Emre; Yavuzer, Dilek; Aydin, Fatih Muhammed; Salepci, Taflan; Oncel, Mustafa; Gumus, Mahmut
Background: The prognostic significance of perineural invasion (PNI) in gastric cancer has been previously investigated in a few studies, but had not reached a consensus. The aim of this study was to determine the prognostic value of PNI in patients with gastric cancer who underwent curative resection. Materials and Methods: We retrospectively analyzed 238 patients who had undergone curative gastrectomy. Paraffin sections of surgical specimens from all patients were stained with hematoxylin and eosin. PNI was defined when carcinoma cells infiltrated into the perineurium or neural fascicles. PNI and the other prognostic factors were evaluated by univariate and multivariate analysis. Results: PNI was detected as positive in 180 of the 238 patients (75.6%). pT stage, tumor size, lymph node metastasis, clinical stage, tumor differentiation, Borrmann classification, histological type, lymphatic vessel invasion, and blood vessel invasion were closely associated with the presence of PNI. The PNI-positive tumors had significantly larger size and more lymph node metastasis than the PNI-negative tumors (P =.001 and P <.001, respectively). The median survival of the PNI-positive patients was significantly worse than that of the PNI-negative patients (28.1 vs. 64.9 months, P =.001). Multivariate analysis indicated that the positivity of PNI was an independent prognostic factor (P =.02, hazard ratio [HR]: 2.75; 95% confidence interval [95% CI]:1.12-3.13) as were classical clinicopathological features. Conclusion: Our results showed that the frequency of PNI was high in patients with gastric cancer who underwent curative gastrectomy and the proportion of PNI positivity increased with progression and clinical stage of disease. PNI may be useful in detecting patients who had poor prognosis after curative resection in gastric cancer.
AtıfScopus101WoS98OpenAlex108İncele - BildiriYalnız künye2015Determination of the amplitude values with Nakamura (H/V) method and standard spectral ratio (Ssr) method at Ktu Campus
Beker, Y.B.; Sayil, N.; Akin, Ö.
Microtremor method used for engineering seismology is very important for determining of dynamic ground parameters and its variations. Method based on frequency of horizontal and vertical component microtremor records provides to quick and economical estimation of dynamic ground parameters. In this study, Nakamura (H/V) method and Standard Spectral Ratio (SSR) method have been applied to microtremor records taken with CMG-6TD three component broad band velocity seismometers in six profile with the aim of determining ground amplification of Karadeniz Technical University Campus area. The amplification maps of the study area are generated to the results of Nakamura (H/V) method and Standard Spectral Ratio (SSR) method and the results have been compared.
- BildiriYalnız künye2014Weyl numbers of diagonal matrices
Ismailov, Zameddin I.; Cona, Lale; Çevik, Elif Otkun; Guler, Bahadir O.
In this work, a connection between Weyl numbers of the infinite diagonal matrix with linear bounded operator elements in the direct sum of Banach spaces and its coordinate operators has been investigated.
AtıfScopus1OpenAlex2İncele - MakaleYalnız künye2010Scopus SJRQ3Responses of some wheat genotypes and their F2 progenies to salinity and heat stress
Yildirim, Mehmet; Bahar, Bilge
Both heat and salinity cause yield decrease in wheat. Grain yield in wheat has increased as a result of breeding efforts for different stress conditions. However, there are still substantial opportunities to improve grain yield by using conventional breeding under stress conditions, like heat and salt stress. The objective of this study was to investigate heat and salt effects on yield and some agronomic traits of four wheat genotypes and their six half F2 diallel cross progenies grown in pots. Significant differences were found among the genotypes for grain yield under both heat stress and non-stress condition. There was a mean reduction in yield of 12.6% due to salt stress. The reduction in biomass was higher than grain yield under salt stress while it was lower at heat stress. Grain yield was positively correlated with spike weight, harvest index, grain numbers per plant and biological yield under non stress (NS), heat stress (HS) and salt stress (SS) conditions. Cultivars Seri 82 and Chil's had high yield among parents under both NS and SS. Chil's and its hybrids showed low reduction in yield due to SS; thus, exhibiting salt tolerance. Also, Chil's was found to be good combiner with high General Combining Ability (GCA) effects for grain yield under SS conditions. 84 CZT04 was the most susceptible cultivar under SS. Significant GCA effects of Genç 99 and 84CZT04 provided positive contribution to grain yield under HS. It was impossible to select both heat and salt tolerant genotype with high yield capacity from the used genotypes. However, heat or salt tolerant genotypes can be improved by selection breeding due to genetic variation among genotypes.
AtıfScopus9WoS7İncele - MakaleYalnız künye2010Scopus SJRQ1Late Cretaceous high-K volcanism in the eastern Pontide orogenic belt: Implications for the geodynamic evolution of NE Turkey
Eyüboǧlu, Yener
High-K volcanics were produced in two different Late Cretaceous cycles during the infilling of back-arc basins of the eastern Pontides. The first cycle, represented by shoshonitic trachyandesites and associated pyroclastics, containing high K2O (2.74-4.81 wt-%) and NaK2O (3.60-5.51 wt-%), overlies a mid-Cretaceous ophiolitic-olistostromal melange formed during the rifting stage of a back-arc basin (Neotethys). 40Ar39Ar dating of biotite from trachyandesite at the base of the first cyle indicates that shoshonitic volcanism in the far south of the eastern Pontides started in the early Campanian. Volcanic rocks of this cycle are overlain by upper Campanian-Maastrichtian rudist-bearing reefal limestones. The second cycle of high-K volcanism is represented by analcime-bearing volcanic rocks erupted in a Neotethyan lagoonal environment. These volcanic rocks, intercalated with continental detritus, are characterized by high a2O (3.22-7.16 wt-%), now concentrated in secondary analcime crystals. Their K2O contents also range between 0.83 and 6.05 (wt-%). All of these units are disconformably overlain by Eocene turbidites with a basal conglomerate. Volcanic rocks belonging to both cycles show various enrichment degrees in LILE, HFSE, LREE, and HREE with respect to primitive mantle and chondrite [(La/Lu) cn=11.10-25.89]. Negative Nb, Ta, Zr, Hf, and Ti anomalies are typical of these subduction-related arc magmas. Geochemical similarities between the two volcanic cycles suggest that trachyandesites and analcime-bearing volcanics were derived from similar enriched mantle sources, and that they formed in the same geotectonic setting of a back-arc basin environment of the eastern Pontide magmatic arc during the Late Cretaceous. In addition, Nd-Sr and Pb isotope ratios of the investigated volcanic units indicate that their mantle melt sources were similar. The new geological, geochemical and isotopic data suggest that southward subduction of the Palaeotethyan oceanic crust can be separated into two main stages for the late Mesozoic Pontide orogenic belt. Early southward subduction ended by slab break-off during the mid-Cretaceous, resulting in upwelling and injection of asthenospheric mantle that caused the opening of the eastern Pontide back-arc basin (Neotethys). Resumption of southward subduction began with intense TH-CA bimodal volcanism in the northern front of the arc during the Turonian-Coniacian. The intensity of this Late Cretaceous magmatism in the north decreased towards the south, and a transition to monogenic calcalkaline-alkaline (CA-A) Campanian andesitic volcanism developed in the southern zone. Yet farther south, andesitic igneous activity graded into the Campanian-Maastrichtian shoshonitic and ultrapotassic volcanism in the Bayburt-Maden, Tokat, Amasya, and Gümüshaciköy areas. This zoning of the Late Cretaceous arc magmatism (TH-CA, CA-A and shoshonitic-ultrapotassic, from north to south) also supports the concept of southward subduction during late Mesozoic evolution of the eastern Mediterranean region.
AtıfScopus120WoS110OpenAlex117İncele - MakaleYalnız künye2014Scopus SJRQ3Well-posedness of fractional parabolic differential and difference equations with Dirichlet-Neumann conditions
Ashyralyev, Allaberen; Emirov, Nazar; Cakir, Zafer
We study initial-boundary value problems for fractional parabolic equations with the Dirichlet-Neumann conditions. We obtain a stable difference schemes for this problem, and obtain theorems on coercive stability estimates for the solution of the first order of accuracy difference scheme. A procedure of modified Gauss elimination method is applied for the solution of the first and second order of accuracy difference schemes of one-dimensional fractional parabolic differential equations.
AtıfScopus12WoS6İncele - MakaleYalnız künye2013Adaptive multi-step differential transformation method to solve ODE systems
Gökdoǧan, Ahmet; Merdan, Mehmet
In this paper, it is given a fast algorithm to solve chaotic differential systems using the multi-step differential transforms method (MsDTM). The approach is applied to a number of chaotic nonlinear differential equations and numerical results are given. Performance analyses reveal that the proposed approach is an efficiency tool to solve using fewer time step to the considered equation systems.
AtıfScopus6WoS4İncele - MakaleYalnız künye2013Scopus SJRQ1Evaluation of the effect of earthquake frequency content on seismic behavior of cantilever retaining wall including soil-structure interaction
Cakir, Tufan
A three-dimensional backfill-structure-soil/foundation interaction phenomenon is simulated using the finite element method in order to analyze the dynamic behavior of cantilever retaining wall subjected to different ground motions. Effects of both earthquake frequency content and soil-structure interaction are evaluated by using five different seismic motions and six different soil types. The study mainly consists of three parts. In the first part, following a brief review of the problem, the finite element model with viscous boundary is proposed under fixed-base condition. In the second part, analytical formulations are presented by using modal analysis technique to provide the finite element model verification, and reasonable agreement is found between numerical and analytical results. Finally, the method is extended to further investigate parametrically the effects of not only earthquake frequency content but also soil/foundation interaction, and nonlinear time history analyzes are carried out. By means of changing the soil properties, some comparisons are made on lateral displacements and stress responses under different ground motions. It is concluded that the dynamic response of the cantilever wall is highly sensitive to frequency characteristics of the earthquake record and soil-structure interaction.
AtıfScopus111WoS90OpenAlex114İncele - MakaleYalnız künye2015Scopus SJRQ3Locally boundedness and continuity of superposition operators on double sequence spaces Cr0
Sağir, Birsen; Güngör, Nihan
Let R be set of all real numbers, N be the set of all natural numbers and N2 = N×N. In this paper, we define the superposition operator Pg where g: N2×R → R by Pg ((xks)) = g(k,s,xks) for all real double sequence (xks). Chew & Lee [4] and Petranuarat & Kemprasit [11] have characterized Pg: c0 → l1 and Pg: c0 → lq where 1 ≤ q < ∞, respectively. The main aim of this paper is to construct the necessary and sufficient conditions for the boundedness and continuity of Pg: Cr0 → L1 and Pg: Cr0 → Lp where 1≤ p< ∞.
AtıfScopus1İncele - MakaleYalnız künye2014Scopus SJRQ3A study on some characteristics of new registered triticale (X Triticosecale Wittm.) varieties (Aysehanim and Mehmetbey) in Turkey
Yildirim, Mustafa; Gezginc, Hasan; Paksoy, Ali Haydar; Aktas, Bekir; Cakmak, Mustafa; Belen, Savas; Bolat, Necmettin; Yorgancilar, Ozcan; Keser, Mesut; Braun, Hans-Joachim
The spring triticale cultivars Aysehanim and Mehmetbey (X Triticosecale Wittm.) were developed by Agricultural Research Station of The Eastern Mediterranean Transition Zone and they had been registered by Variety Registration and Seed Certification Center in Turkey. In this experiment, some characteristics of two new varieties were studied. The experiments were conducted at four locations of the Eastern Mediterranean Transition Zone in Turkey with three check triticale cultivars (Egeyildizi, Taceddinbey and Focus) under rain-fed conditions during the 2009 – 2010 and 2010 – 2011 growing seasons. The locations were Kahramanmaras, Adana and Hatay provinces and Ceyhan town. The genotypes were tested for agronomic, quality and botanical characteristics. Also, resistance of some cereal disease and lodging of the genotypes were determined. Aysehanim and Mehmetbey cv. had good adaptation and agronomic performance in the Eastern Mediterranean Transition Zone. The grain yields of Aysehanim and Mehmetbey cv. were 6459 and 6387 kg ha-1, respectively, and these values were significantly higher than the grain yields of Egeyildizi and Focus check cultivars, 5916 and 4919 kg ha-1, respectively. The cultivars had acceptable quality traits compared to the check cultivars. While their hectolitre weights and 1000 kernel weights were higher than the averages of check cultivars, protein content was not higher than those of the checks. Aysehanim and Mehmetbey cv. had good resistance for rust disease and lodging.
- MakaleAçık Erişim2013Scopus SJRQ2The effect of prenatal exposure to 900-MHz electromagnetic field on the 21-old-day rat testicle
Hanci, Hatice; Odaci, Ersan; Kaya, Haydar; Aliyazicioǧlu, Yüksel; Turan, Ibrahim; Demir, Selim; Çolakoǧlu, Serdar
The aim of this study was to investigate the effect of exposure to a 900-MHz electromagnetic field (EMF) in the prenatal term on the 21-old-day rat testicle. Pregnant rats were divided into control (CG) and EMF (EMFG) groups. EMFG was exposed to 900-MHz EMF during days 13-21 of pregnancy. Newborn CG rats were obtained from the CG and newborn EMFG (NEMFG) rats from the EMFG. Testicles were extracted at postnatal day 21. Lipid peroxidation and DNA oxidation levels, apoptotic index and histopathological damage scores were compared. NEMFG rats exhibited irregularities in seminiferous tubule basal membrane and epithelium, immature germ cells in the lumen, and a decreased diameter in seminiferous tubules and thickness of epithelium. Apoptotic index, lipid peroxidation and DNA oxidation were higher in NEMFG rats than in NCG. 21-day-old rat testicles exposed to 900-MHz EMF in the prenatal term may be adversely affected, and this effect persists after birth.
AtıfScopus65WoS60OpenAlex64İncele - MakaleYalnız künye2015Scopus SJRQ2Assessment of bearing capacity and permeability of foundation rocks at the Gumustas Waste Dam Site (NE Turkey) using empirical and numerical analysis
Alemdag, Selcuk
In this study, the bearing capacity and permeability of andesite and andesitic breccia rock masses, forming the basement for Gumustas waste dam, planned as a rock fill housing, were evaluated using various empirical equations and numerical analysis. The total stress constituting over the basement caused through ore waste building up in the body of dam and reservoir was determined by a finite element method. Then, this stress was compared with bearing capacities calculated for the rock masses. The permeability of rock masses in dam site and the lake were appraised with pressure water test experiments (Lugeon method), performed within opened bore holes and finite element method (seepage analysis). Since chemicals seeping from waste dams into the ground water are of vital importance for human health and the environment, the dam body must be made completely impervious using upstream slope and reservoir geosynthetics.
AtıfScopus30WoS24OpenAlex39İncele - MakaleAçık Erişim2014Scopus SJRQ2High order of accuracy difference schemes for the inverse elliptic problem with Dirichlet condition
Ashyralyyev, Charyyar
The overdetermination problem for elliptic differential equation with Dirichlet boundary condition is considered. The third and fourth orders of accuracy stable difference schemes for the solution of this inverse problem are presented. Stability, almost coercive stability, and coercive inequalities for the solutions of difference problems are established. As a result of the application of established abstract theorems, we get well-posedness of high order difference schemes of the inverse problem for a multidimensional elliptic equation. The theoretical statements are supported by a numerical example.
AtıfScopus30WoS29OpenAlex26İncele - MakaleYalnız künye2012Scopus SJRQ1The modified algorithm for the differential transform method to solution of Genesio systems
Gökdoĝan, Ahmet; Merdan, Mehmet; Yildirim, Ahmet
In this article, approximate analytical solution of chaotic Genesio system is acquired by the modified differential transform method (MDTM). The differential transform method (DTM) is mentioned in summary. MDTM can be obtained from DTM applied to Laplace, inverse Laplace transform and Padé approximant. The MDTM is used to increase the accuracy and accelerate the convergence rate of truncated series solution getting by the DTM. Results are given with tables and figures.
AtıfScopus51WoS40OpenAlex63İncele - MakaleAçık Erişim2015Scopus SJRQ1Acethylcholinesterase inhibitory potential and antioxidant properties of pyrogallol
Ozturk Sarikaya, S. Beyza
Pyrogallol is found naturally in crops and fruits of many plants. It is also an active ingredient of many pharmaceuticals. For this reason, we employed different in vitro antioxidant assays such as cupric ion Cu2+ reducing power, Fe3+ reducing power, total antioxidant activity by ferric thiocyanate method, ABTS radical scavenging, DMPD radical scavenging, DPPH • scavenging, Fe2+ chelating, O2•- scavenging and H2O2 scavenging activities of pyrogallol. Pyrogallol inhibited 77.95% lipid peroxidation of linoleic acid emulsion at 30 μg/mL concentration. BHA, BHT, α-tocopherol and trolox exhibited inhibitions of 89.88, 89.97, 83.82 and 91.85% against peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, pyrogallol was an effective of all the scavenging and reducing power results. In this study, pyrogallol was also evaluated as potential inhibitor for acethycholinesterse enzyme. The results showed that pyrogallol exhibited potent acetylcholinesteras inhibitory activity with IC50 and Ki values 10.2 and 8.6 μM, respectively.
AtıfScopus71WoS62OpenAlex76İncele - MakaleAçık Erişim2011Scopus SJRQ3Bay laurel (Laurus nobilis L.) in Japanese quails feeding 1. Performance and egg quality parameters
Karaalp, Musa; Elmasta, Mahfuz; Genc, Nusret; Sezer, Metin; Yavuz, Musa; Ozkan, Mehmet
The aim of this study was to evaluate the effect of supplemented bay laurel (Laurus nobilis L.) leaves to a conventional diet of laying Japanese quail on the performance and some egg quality. A total number of 60 and 54 days old laying type quails were distributed into individual cages for three different treatments. The control diet did not containLaurus nobilis (LN) leaves (LNG) and the other diets were supplemented with 2 g (LN2) and 4 g (LN4) leaves kg-1, respectively. The trial lasted for a total of 10 weeks. Supplemented leaves of LN (2 or 4 g kg-1 feed) had no effect on any performance parameters, external and internal egg quality traits of quails. The diets have not changed the amount of egg yolk total cholesterol at 121 days old. However, egg yolk triglyceride concentration of quails fed LN4 diet was lower (p<0.01) than quails fed with the other diets at 121 days old. Besides, the amount of total cholesterol and triglyceride of egg yolk increased (p<O.01) in all of the groups with age. In egg yolk in the group receiving diet LN4, the level of palmitic acid was lower (p<0.05) and oleic acid was higher (p<0.05) than those of the other 2 groups at 118 days. Besides at that age, the level of pahnitic acid was lower and oleic acid was >55, 76 and 97 days. There was no change in the other fatty acids. The changes in total saturated and total monounsaturated fatty acids were parallel with palmitic acid and oleic acid, respectively. Total polyunsaturated fatty acid content in the present study did not change with diet and age. The results of this study demonstrated that supplemented a conventional diet with LN could change some biochemical parameters of quail egg yolk.
AtıfScopus14WoS9OpenAlex15İncele
