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- MakaleYalnız künye2020Mineralogy, chemistry, and genesis of zeolitization in Eocene tuffs from the Bayburt area (NE Turkey): Constraints on alteration processes of acidic pyroclastic deposits
Cicerali, Derya; Arslan, Mehmet; Yazar, Emel Abdioglu; Yücel, Cem; Temizel, Irfan; Park, Sohyun; Schroeder, Paul A.
Eocene vitric tuffs in the Bayburt area (NE Turkey) possess a dacite-rhyodacite composition and contain abundant altered glass shards and flattened fibrous pumice with lesser amounts of pyrogenic minerals (plagioclase, quartz, biotite, and sanidine). Zeolitization is common and generally develops in the glassy components. The main zeolite mineral found in the tuffs is clinoptilolite, with lesser amounts of analcime and mordenite (?). Smectite is the dominant clay mineral, with lesser amounts of kaolinite also present. Opal-CT, calcite, and dolomite occur as secondary minerals. Scanning electron microscopy studies reveal the dissolution of glass, with the development of popcorn-textured smectites and tabular clinoptilolites developed. The opal-CT spheres found on the clinoptilolite crystals appear to have crystallized simultaneously and are due to excess silica in the environment. Fibrous mordenite (?) also developed on the clinoptilolites. In the clinoptilolites R-r = 0.81-0.82, Si/Al = 4.20-4.70, and K+ is the dominant exchangeable cation (0.65-3.30) seen, together with lesser amount of Ca2+ (0.39-2.25) and Na+ (0.02-2.16). The degree of zeolitization increases with the content of glassy component in the tuffs. The formation of K-clinoptilolite is controlled by the SiO2/Al2O3 (4.9-7.0) and K2O/Na2O (0.8-10.8) ratios in the zeolitized tuffs. delta O-18(V-SMOW) and delta DV-SMOW values of clinoptilolite-rich tuffs range from 22 to 25.6960 and from -96 to -111 parts per thousand, respectively, which suggests that zeolitization occurred at low temperatures (30-55 degrees C) via fluid-rock interactions. Smectite was initially formed from the devitrification of glassy components and is associated with the increase in (Na+ +K+ +Ca2+)/H+ activity and the presence of high pH similar to-9-10) fluids. The zeolites subsequently developed within a saline-alkali shallow marine environment.
- MakaleYalnız künye2023Characterization of the Adsorption Mechanism of Cadmium(II) and Methylene Blue upon Corncobs Activated Carbon
Gundogdu, Ali; Bozbeyoglu, Pinar; Imamoglu, Mustafa; Baltaci, Cemalettin; Duran, Celal; Bulut, Volkan N.
A promising new activated carbon (AC) was produced from corncobs (CCs) by boric acid-based chemical activation to remove methylene blue (MB) as an organic pollutant and cadmium ions (Cd2+) as an inorganic pollutant from aqueous solutions. After the produced activated carbon (CCs-AC) was characterized, the adsorption mechanism of CCs-AC, which is one of the most interesting topics in the literature, was the primarily focus. The possible adsorption mechanisms of Cd2+ and MB on CCs-AC from aqueous solutions are discussed with respect to pH, thermodynamic values, and regeneration parameters. The results show that the adsorption of Cd2+ on CCs-AC was favorable at pH values higher than 4. In contrast, the adsorption process was almost pH-independent for MB. Variation of pH showed that the adsorption of Cd2+ on CCs-AC primarily occurs by electrostatic interaction. However, MB adsorption may also involve pi-pi dispersion forces and partial hydrogen bonding. The Cd2+ adsorbed on CCs-AC was quantitatively desorbed by HCl, whereas MB was not desorbed quantitatively by any solution. While a temperature increase has a positive effect on the adsorption of both methylene blue and Cd2+, the thermodynamic results show that MB adsorption is primarily chemisorption (Delta H of 24.28 kJ/mole), while Cd2+ adsorption is mostly physisorption (Delta H of 7.20 kJ/mole). Using Langmuir adsorption isotherms, the MB adsorption capacity of CCs-AC, which primarily has a microporous structure, was 0.88 mmol/g, while the Cd2+ adsorption capacity was 1.28 mmol/g.
- BildiriYalnız künye2006Is postprandial 2h glucose level a real determinant for glucose intolerance in people at risk for type 2 diabetes? RISK study results - I
Yilmaz, T.; Sargin, M.; Olmez, B.; Karadeniz, S.; Oguzhan, B.
- MakaleYalnız künye2013Assessment of Radiological Levels at Schools in Trabzon, Turkey
Çevik, Ugur; Çelik, Ahmet; Çelik, Necati; Özkalayci, Fatih; Akbulut, Songul
In this study, a survey on environmental radioactivity in 16 high schools located in north eastern region of Turkey (the black sea region, province of Trabzon) was carried out. Indoor air radon (Rn-222) concentrations were measured in spring and autumn 2008 seasons using LR115 solid state nuclear track detectors and gamma radioactivity levels were measured using an HPGe gamma ray detector. It was seen that mean radon activity concentrations in schools ranged from 31 to 157 Bq/m(3) for spring season and from 38 to 114 Bq/m(3) for autumn season. The mean gamma activity concentrations in located areas of schools are between 18-52, 21-59, 11-97 and 265-759 Bq/kg for Ra-226, Th-232, Cs-137 and K-40, respectively. The annual effective doses of students and staff received due to radon and locations' gamma radioactivity levels are calculated.
- MakaleYalnız künye2018Automatic extraction of sparse trees from high-resolution ortho-images
Bayram, Bulent; Seker, Dursun Zafer; Jamil, Akhtar; Reis, Hatice Catal; Demir, Nusret; Bozkurt, Salih; Ince, Abdulkadir; Kucuk, Turgay
Obtaining information about tree species distribution in agricultural lands is a topic of interest for various applications, such as tree inventory, forest management, agricultural land management, crop estimation, etc. This information can be derived from images obtained from modern remote sensing technology, which is the most economical way as compare to field surveys covering large geographic areas. Therefore, in this study, a new method is proposed for extraction and counting of sparse and regular distributed individual pistachio trees from agricultural areas on large scale from high-resolution digital ortho-photo maps, which were obtained using an airborne sensor (Ultracam-X). The input images were first smoothed by applying Gaussian filter to reduce the impact of noise. Normalized difference vegetation indices (NDVI) were then derived to obtain vegetation areas followed by Otsu's global thresholding algorithm to obtain candidate tree areas. Further, connected component (CC) analysis was applied to segregate each object. Morphological processing was performed to fill holes within tree objects and get smooth contours, which were obtained by using the Moore-neighbor tracing method (MNTM) for each CC, while geometrical constraints were applied to undermine possible non-tree elements from output image. To further improve the segmentation results for sparse trees, a new method was applied, called quadratic local analysis (QLA). QLA helped to segment the trees, which were missed by the Otsu method due to low contrast and resulted in improved accuracy (3-6%). The obtained results were compared with well-known support vector machine (SVM) classifier. Proposed method produced slightly better results (1-5%) than SVM for extraction of pistachio trees and obtained accuracy for QLA and SVM were 96 and 91% for region 1, while 91 and 90% for region 2 respectively.
- MakaleAçık Erişim2023The Epiphytic Bryophyte Vegetation of Buxus sempervirens L. forests in the Firtina Valley (Rize, Turkey)
Alatas, Mevlut; Ezer, Tulay; Erata, Huseyin; Batan, Nevzat; Ursavas, Serhat
The Firtina Valley forests are of the 100 forests in the world whose conservation is a priority due to the natural old forests they have. In this study, the epiphytic bryophyte vegetation of the Buxus sempervirens L. forests located in the Firtina Valley (Rize, Northern Turkey), which is one of the nine hotspots in Turkey and Turkey's only boxwood forest, was investigated. The releves taken from living tree trunks in 2020 were analyzed according to the Braun-Blanquet methodology, and ordinated and classified using the Detrended Correspondence Analysis (DECORANA) and the Two-Way Indicator Species Analysis (TWINSPAN). As a result of the analyses, Exsertotheco crispae-Allenielletum besseri ass. nov. subass. typicum and leucodontetosum sciuroidis subass. nov., and Alleniello besseri-Palamocladietum euchloronis ass. nov. were described and characterized. All syntaxa were presented by analyzing them in terms of their ecological and floristic classifications.
- MakaleAçık Erişim2024Investigation of Microbiological, Physiological and Histopathological Changes in Polymicrobial I nfection in Old Rats
Ulker, U.; Kizil, S.; Bayraktar, B.; Alçigir, M. E.; Kul, O.; Kaya, H.; Ürüsan, H.; Aydemir, S.; Kotan, G. C.; Önel, A. U.
Background: The aim of this study is to examine the microbiological, clinical, physiological and pathological findings of natural polymicrobial infection developing in a wistar rat colony under long-term observation. Methods: In this study, 70 male Wistar albino rats, 3 years old, raised by conventional methods and housed in a cage environment were used. Thirteen rats with clinical symptoms such as torticollis and rotation were sacrificed for microbiological and histopathological examination after 14 days. For microbiological examination, the rapid diagnostic kit BBL Crystal system was used to identify bacterial agents in tissue and stool samples and the traditional culture method was used for isolation. Result: As a result of microbiological analysis, the rarely isolated Staphylococcus capitis ( S. capitis ) was isolated. Different Staphylococcus spp. It has been determined that the species can cause suppurative meningoencephalitis as well as septicemia in the brains of experimental animals., it is thought that polymicrobial infection will be useful for the identification of bacterial agents and infection prevention and treatment strategies.
- Derleme MakaleAçık Erişim2025Therapeutic Bioactivity Exerted by the Apis mellifera Bee Venom and Its Major Protein Melittin: A Scoping Review
Erdogan, Perihan Mutlu; Bilgili-Tetikoglu, Funda; Çelik-Uzuner, Selcen; Yildiz, Oktay; Kolayli, Sevgi; Mossialos, Dimitris
Honey bee (Apis mellifera) products have been extensively utilized in traditional medicine. Bee venom (BV) is one of the major bee products with a high concentration of the small peptide melittin (MEL) and exerts bioactivity ranging from anti-microbial to anti-inflammatory and anti-cancer. This scoping review aims to sum up research articles on the bioactivity exerted by BV and MEL published in PubMed and Scopus from 2010 onwards. PRISMA guidelines were implemented to analyze the relevant literature; we ended up with 425 research articles. Bioactivity of BV and MEL was grouped as (i) anti-inflammatory (85), (ii) immunomodulatory (37), (iii) anti-microbial (179), (iv) anti-cancer (170), and (v) anti-oxidant (32). Although there is a significant body of research on the anti-cancer and anti-microbial activity of BV and MEL, their anti-oxidant, anti-inflammatory and immunomodulatory properties have received comparatively less attention. Many studies on the immunomodulatory effects of BV or MEL have focused on cancer. However, the effects on Parkinson's and Alzheimer's disease have not been extensively studied regarding the anti-inflammatory effects. Given the critical role of the immune system and inflammatory response in cancer, neurodegenerative diseases, senescence and against infections, it is paramount to further explore the immunomodulatory and anti-inflammatory potential of BV and MEL.
- MakaleAçık Erişim2025Exploring the acute recovery effects of dry cupping therapy and electrical stimulation on anaerobic performance metrics in active individuals: A quasi-experimental crossover study
Can, Ibrahim; Yerlikaya, Gokhan; Yalçin, Seda; Bayrakdaroglu, Serdar; Kayhan, Recep Fatih; Uluç, Ender Ali; Stefanica, Valentina; Ceylan, Halil Ibrahim
Background:This quasi-experimental crossover study aimed to examine the acute effects of dry cupping therapy (DCT) and neuromuscular electrical stimulation (NMES) on fatigue and perceived exertion in anaerobic performance among physically active individuals.Methods:Twelve male participants (mean age: 24.1 +/- 2.37 years), all students from the Faculty of Sports Sciences, were recruited to participate voluntarily. Anaerobic performance parameters, including peak power, mean power (MP), and fatigue index (FI), were assessed using a Monark 839E cycling ergometer under 3 distinct conditions: NMES, DCT, and a control condition (no intervention), with each session separated by a 48-hour rest period. Perceived exertion was evaluated immediately following each test session using Borg's rate of perceived exertion (RPE) scale. Both NMES and DCT were administered bilaterally to the hamstring (m. hamstring) and quadriceps femoris (m. quadriceps femoris) muscles for 20 minutes before testing.Results:The results revealed no statistically significant differences in peak power and MP across the conditions. However, significant effects were identified for FI (F(2, 22) = 4.08, P = .031, eta p(2) = 0.27) and RPE (F(2, 22] = 8.88, P = .0015, eta p(2) = 0.45). Post hoc pairwise comparisons indicated that NMES significantly reduced FI compared to the control condition (P = .0311), with a small to medium effect size (Cohen's d = 0.44). In terms of RPE, DCT significantly lowered values compared to both the control (P = .0018) and NMES conditions (P = .0005), demonstrating medium (Cohen's d = 0.74) and small to medium (Cohen's d = 0.37) effect sizes, respectively.Conclusions:While NMES and DCT did not elicit acute improvements in peak or mean anaerobic power, both interventions effectively mitigated fatigue and reduced perceived exertion during maximal anaerobic exercise. These findings suggest that NMES and DCT may serve as valuable recovery modalities for mitigating fatigue in sports characterized by high anaerobic demands. Future research should investigate the chronic effects of these interventions and explore their utility among trained athletes to determine their broader applicability in enhancing athletic performance.
- MakaleYalnız künye2026Computational gamma-ray attenuation and fast-neutron removal cross-section assessment of CrN, AlCrN and AlTiCrN ceramic coatings using EGS4 Monte Carlo and Phy-X/PSD
Sirin, Murat; Kaya, Selim; Aktarer, Semih Mahmut; Baltas, Hasan; Küçükömeroglu, Tevfik
In this study, the computationally predicted gamma-ray attenuation behavior and fast-neutron removal cross-section characteristics of micrometre-scale CrN, AlCrN, and AlTiCrN ceramic coatings produced via cathodic arc evaporation were investigated. The shielding parameters were not measured by direct gammaor neutron-transmission experiments; instead, mass attenuation coefficients (MAC, mu/rho) in the 0.05-2.50 MeV range were obtained from EGS4 Monte Carlo simulations and Phy-X/PSD calculations, and the agreement between the two computational datasets was evaluated. Energy-dependent attenuation parameters, including half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), radiation protection efficiency (RPE), and kerma coefficients, were calculated. Statistical comparison showed good consistency between EGS4 and Phy-X/PSD for MAC, RPE, HVL, MFP, and kerma coefficients, whereas Zeff exhibited larger method-dependent deviations. All coatings showed higher attenuation at low photon energies due to the photoelectric effect, while Compton scattering dominated at intermediate energies. Among the investigated coatings, CrN exhibited the most favorable calculated gamma-ray attenuation indicators, with lower HVL and MFP values and higher RPE values. The macroscopic fast-neutron removal cross-section (Sigma R) was also calculated as a first-order neutron attenuation indicator, and CrN showed the highest Sigma R value. Considering their limited thickness of approximately 2.3-2.8 mu m, these coatings should not be regarded as replacements for conventional bulk radiation shields. Instead, nitride-based ceramic coatings may serve as secondary or multifunctional surface layers in space-restricted components requiring local radiation attenuation and mechanical durability.
