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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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Karaelmas Science and Engineering Journal
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  This is an Open Access Journal Open Access journal
ISSN (Print) 2146-4987 - ISSN (Online) 2146-7277
Published by Bülent Ecevit University Homepage  [4 journals]
  • The Effect of Levamisole on Some Biological Parameters of Model Organism
           Galleria mellonella

    • Authors: Volkan KELEŞ; Ender BÜYÜKGÜZEL
      Abstract: The effects of levamisole, an imidothiazole derivative anthelmintic, on survival rate, development time and adult longevity of greaterwax moth, Galleria mellonella, larvae, pupae and adult stage were investigated. First instar larvae of G. mellonella were fed on artificialdiet containing 0,001, 0,01 and 0,1 g/100 g of levamisole. Experimented levamisole concentrations negatively affected the survivaland developmental parameters of G. mellonella when compared to the control diet without levamisole. The concentrations of 0,001%g and 0,01% g of levamisole significantly decreased survival rates of 7th instar larvae when compared to the control group. Similarresults obtained from the survival of pupal and adult stages. Insects that fed on artificial diet with different concentrations of levamisolereached the 7th instar larva, pup and adult stages later than the control group without levamisole. While the concentrations of 0,001% gand 0,01% g of levamisole extended adult longevity of insect, the highest concentration of levamisole tested (0,1% g) reduced the adultlongevity of the insect by approximately 3 days compared to the control group. As a result, it has been demonstrated that levamisoletaken with artificial diet has negative effects both in the larval stage that shows active feeding and in the subsequent developmentalstages, including the pupal and adult stages of model organism G. mellonella.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Deposition of TiO2-Doped Diamond-Like Carbon Films From a New Solution and
           Their Characterizations

    • Authors: Necati BAŞMAN; Mehmet GÖKÇEN, Cengiz TEMİZ
      Abstract: Diamond-like carbon (DLC) films are the most studied coating materials due to their mechanical and physical properties. Manystudies have been conducted on the deposition methods and doping to improve the properties of these films. Among the depositionmethods, the electrochemical deposition has advantages such as convenience and inexpensive equipment. In our previous study, wewere able to produce a titanium dioxide (TiO2) doped DLC film by electrochemical method from a mixture of methanol (CH3OH)and titanium solution obtained by dissolving titanium metal in hydrogen peroxide (H2O2). In this study, TiO2 doped DLC films weredeposited by electrolysis of solutions formed from a mixture of titanium isopropoxide (TTIP) and methanol. The films deposited attwo different TTIP concentrations were characterized morphologically, structurally and elementally. Scanning electron micrographswere shown that the films are homogeneous and compact. No change was observed in the morphology of the films after annealingthe films at 600 0C. Chemical analyses showed that titanium was in the form of TiO2 and the amount of titanium increased withincreasing TTIP concentration. X-ray diffraction analysis revealed that TiO2 was amorphous in the DLC matrix and the film preparedwith lower TTIP concentration had diamond content. After annealing at 600 0C, it was seen that this film was graphitized. Theobtained findings showed that TiO2 doped DLC nanocomposite films can be easily deposited with the solution proposed in this study.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Drosophila: A Promising Model for Evaluating the Toxicity of Environmental
           Pollutants

    • Authors: Eşref DEMİR; Fatma TURNA DEMİR
      Abstract: Environmental contamination has now become a major global issue with adverse effects on our health and food security. Humans andanimals are being exposed to debilitating levels of contamination on a daily basis. Across the globe, air pollution alone causes millionsof premature deaths annually, mainly from lung cancer, chronic obstructive pulmonary disease (COPD), stroke, heart failure, andrespiratory infections, and according to World Health Organization (WHO), 99% of humanity breathes air containing contaminantsabove recommended levels. The United Nations (UN) has identified “a pollution-free planet” goal among its three pillars, besidesclimate change and biodiversity for 2022–2025. In order to mitigate contamination and relieve our burden of pollution-related disease,we need to devise target-specific strategies. To that end, risk assessment of each chemical and natural contaminants and solid evidencefrom toxicity studies appear to be of paramount importance. Meticulous efforts should be made to look into possible mechanismsof action for each pollutant and detect their toxic potential and safe limits through comprehensive in vivo animal testing. Variousfactors such as high operational costs and ethical issues concerning the use of higher vertebrates frustratingly restrict the efficient useof traditional in vivo testing. Therefore, simpler and more dynamic model organisms like Drosophila melanogaster could be favoredfor toxicity studies, as 75% of the genes related with human diseases are known to have homologs in D. melanogaster, which facilitatesresearch into different anomalies. This review aims to present the picture of studies regarding environmental pollutants that employedusing D. melanogaster, attempting to offer a comprehensive analysis of risks involved in exposure to environmental pollutants.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Determination of in Vitro Effects of Metal Ions (Zn+2, Co+2, Cd+2, Ni+2)
           on the Hepatopancreas Esterase (E. C. 3.1.1.1) Activity of Callinectes
           sapidus (Blue Crab)

    • Authors: Salih GÖRGÜN
      Abstract: In this study, in vitro effects of zinc (Zn), cobalt (Co), cadmium (Cd), nickel (Ni) on the hepatopancreas esterase (E. C. 3.1.1.1)activity of Callinectes Sapidus (Rathbun, 1896), a crab species consumed as a food by humans, were investigated. According to theobtained results; IC50 values were found to vary between 0.83 mM (Cd) and 32.21 mM (Co), in addition to the inhibition effect of allthe metal ions investigated on the hepatopancreas esterase activity. When assessed the inhibition types of the metal ions investigated,while Zn and Co caused un-competitive inhibition, Cd and Ni had exhibited mixed type inhibition. The data obtained providebiochemical data on the role of blue crab in determination of environmental metal pollution.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Investigation of Disinfection By-Products Formation in Disinfection of
           Drinking Water Sources with Chlorine and Chlorine Dioxide: Istanbul Case
           Study

    • Authors: Kadir ÖZDEMİR
      Abstract: In this study, formation of disinfection byproducts (DBPs), namely, trihalomethane (THM) during chlorine (Cl2) and chlorinedioxide (ClO2) oxidizing was investigated with reference to key controlling parameters. Terkos Lake Water (TRG), BüyükçekmeceLake Water (BÇG) and Ömerli Dam (OLB) were used as drinking water source in present study. Water samples were oxidized withCl2 and ClO2 doses at the end of given reaction times to observe the formation of THMs in water sources. The structures of naturalorganic matter (NOM) in TRG, BÇG and ÖLB samples were revealed to the organic parameters, namely, total organic carbon(TOC), ultraviole absorbance at 254 nm wavelength (UV254) and specific ultrviole absorbance (SUVA). Among to the chlorinateddrinking water sources, the highest THM concentration was observed as (235,65 μg/l) in TRG samples with dose of Cl2 (10 mg/l)at the end of reaction time of 24 h. Altough THM amounts increased in waters oxidized with Cl2, the trend of decreasing THMamounts with oxidized ClO2 was observed. On the other hand, formation of inorganic DBPs such as chlorate (ClO3-) and chlorite(ClO2-) was evaluated during ClO2 oxidizing. ClO2- and ClO3- levels were determined as 68,51%-13,21% for TRG, 61,05% -12,28%for BÇG and 69,87% -15,67% for OLB.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • The Investigation of the Relationship Between Geometrical Growth and
           Melting Behavior of NiN (N=6-55) Clusters

    • Authors: Meral ERYÜREK
      Abstract: The melting behavior of NiN (N=6-55) clusters was studied, as well as the growing behavior of geometric shapes with the lowestenergy acquired when each atom was added. This was accomplished using the microcanonical Molecular Dynamics (MD) simulationapproach, which employs the Sutton-Chen potential in interparticle interactions. The heat capacity curves were calculated using themultiple histogram method with the caloric curves from MD simulation and the square root of the mean squared (δrms) of the bondlengthfluctuations. How do the heat capacity curves which calculated using the multiple histogram method behave when the atomicnumber increases and the relations of the clusters with the most stable geometries were determined. The maximums of heat capacitycurves corresponding of δ(rms) phase transition region and the graph of change by atomic number for the energy difference betweenglobal minumum and first isomers have been investigated and N=13, 19, 38, 48, 50, 55 clusters were found to be the most stable sizes
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • An Analytical Solution to Conformable Fractional Fokker-Planck Equation

    • Authors: Muammer AYATA; Ozan ÖZKAN
      Abstract: It is the first time in this work that a newly defined conformable Laplace decomposition method (CLDM) is applied to nonlinearfractional Fokker Planck (FP) equation which has a major role in statistical physics. This new algorithm combines conformableLaplace transform and Adomian decomposition method. First, some basic theorems and definitions of fractional derivative are givenin conformable sense. Then, the general algorithm of CLDM is presented. After that, the presented method is supported by numericalexample by the aid of figures. As is seen from the numerical example, conformable Laplace decomposition method is strong, easy touse, reliable and applicable to a wide variety of fractional PDEs.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Determination of Critical Relative Humidity of Construction Materials for
           Mold Growth by Experimental Study

    • Authors: Bahar TÜRK; Mustafa Erkan KARAGÜLER, Dilek ŞATANA
      Abstract: Resistance of materials to mold fungi is directly related to the material properties and the environmental temperature and relativehumidity level. Critical relative humidity occurs when the relative humidity reaches to the point where mold fungi can grow on thesubstrate. A strategy should be developed to address the conditions of mold fungi growth and use more suitable materials dependingon the humidity conditions in the building. The purpose of this research was to establish the essential relative humidity of variousconstruction materials based on their substrate category in order to get a better understanding of mold resistance and to reduce thedanger of mold development. The critical relative humidity for six building materials was determined in this research to assess eachsubstrate category’s resistance to mold growth. Inoculation of construction materials with six mold spores (Penicillium, Cladosporium,Chaetomium, Scopulariopsis, Aspergillus, and Acremonium) and incubation in a desiccator at 22° C (%75-95 ). For 3 months, samples wereanalyzed once a week. Mold growth was most sensitive to substrate category I (gypsum board) in this laboratory experiments. Therewas no evidence of growth in any of the glass or composite samples. The essential moisture level varied according to substrate category.For example, the essential humidity level for drywall (category I) was 80%, whereas for rock wool it was 85% (category II). At variousrelative humidity levels, the time needed for critical mold development varied. Critical mold development times for gypsum board are12 weeks at 75% relative humidity and 1 week at 95% relative humidity. The greater the environment relative humidity, the less timeessential mold development requires on the substrate.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Nano Ozonized Oil Trigger ROS Production and ɣH2AX Cell Positivity of
           B-16 Melanoma and OV-90 Ovarian Cells

    • Authors: Yeliz YALÇIN; İshak Özel TEKİN, Rahime Seda TIĞLI AYDIN
      Abstract: Tumor hypoxia is a restrictive factor for cancer treatment. Ozone therapy, used to decrease or prevent the hypoxia in tumor. In thisstudy, it is aimed to use ozonized oil nanoemulsions (OZNEs) to overcome the limitations of ozone therapy in cancer research. Theinfluence of OZNE against cancer cell lines is evaluated by Reactive Oxygen Species (ROS) and ɣH2AX assays. For both B-16melanoma and OV-90 cell lines, ROS production levels increased due to the increase in OZNE doses (0.85% to 14.88% and 1.94%to 58.58% for B-16 and OV-90 cell lines, respectively). 5-fold higher ɣH2AX cell positivity’s determined in OV-90 cells compared toB-16 melanoma cells. OZNE treatment could provide a new effective method to damage cancer cells in the future.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Dynamic Modelling and Experimental Validation of New Generation High Power
           IGBTs

    • Authors: Osman TANRIVERDİ; Deniz YILDIRIM
      Abstract: In this paper, IGBT dynamic model is characterized by the circuit simulation tool. IGBT datasheet is used for the details need tobuilt dynamic model. After that, the model is used in the double pulse test circuit simulation. And the results compared with the realtest results. Main idea of this research is to have an IGBT dynamic model as close as possible to real one in order to use the model inthe gate drive design simulations. A software tool of Ansys Simplorer is used for the simulations and the IGBT that is used for theresearch is MBM450FS33F. This is the new packaging generation high voltage dual IGBT that has the feature of high power density,low inductance and easy paralleling for the converter applications. Experimental test measurements are also performed with doublepulse test setup. The comparison of the simulation and the experiment results for both voltage and current waveforms, especially peakvalues and the turn off and turn on energy losses are given in detail. The results are shown that the dynamic IGBT model that is builtcan be used for the system simulations. It achieves an acceptable accuracy considering the compared results
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Determination of Total Phenol Contents, Antibacterial and Antioxidant
           Activity of Some Mosses Species

    • Authors: Şükran ÖZTÜRK; Yasin HAZER, Banu KAŞKATEPE, Muhammet ÖREN
      Abstract: The aim of this study were to determine total phenol contents, antibacterial and antioxidant activity of bryophyte species includingPlasteurhynchium striatum (Spruce) M. Fleisch, Palamocladium euchloron (Bruch ex Müll. Hal.) Wijk & Margad. and Cratoneuron filicinum(Hedw.) Spruce and Campyliadelphus chrysophylus (Brid.) R.S. Chopra. Antibacterial activity of methanolic, ethanolic, chloroform,acetone and water extracts of these species was determined by microdilution method. Antioxidant activity of these species wasevaluated by 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging ability. The total phenol content of these species was determinedquantitatively using the folin ciocalteu reagent, with gallic acid equivalents as the standard.The highest DPPH free radical scavenging activity was observed in about 65% C. filicinum. Total phenolic content of P. euchloronwas determined the highest extract value of 0,027±0,002 mg/g. The methanol extract of bryophytes was found to have significantantioxidant activity and phenolic contents. Antibacterial effect of the extracts was not observed against the tested microorganisms
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • The Effect of Mechanical Alloying Time on the Hardness and Electrical
           Conductivity Properties of Cu-Cr Alloys Produced by Hot Pressing Method

    • Authors: Hamza ÇOLAK; Serhatcan Berk AKÇAY, Temel VAROL, Onur GÜLER, Hüseyin Can AKSA
      Abstract: This study concentrated on alloying 0.5% chromium reinforced copper particles by weight by mechanical alloying method accordingto different alloying times and intensifying the produced powders by hot press method. 10:1 ball:powder ratio and 400 rpm rotationspeed were selected as mechanical alloying parameters and the times were determined as 0, 0.5, 1, 2 and 4 hours as variable. Hotpressing parameters were used as constant in all experiments and were determined as 500 ⁰C and 600 MPa. As a result of theexperiments, it was determined that the powders with initially spherical and irregular morphology had a flake-like morphology after0.5 hours of mechanical alloying. In addition, as a result of the experiments, the highest specific surface area was obtained after 1 hourof mechanical alloying and was measured as 0.0667 m2/g. The lowest and highest hardness values of the compact samples producedwithin the scope of this study belong to the samples that were not mechanically alloyed and subjected to 1 hour mechanical alloying,respectively, and were measured as 71.97 HB and 99.12 HB. The highest electrical conductivity value belongs to the sample subjectedto mechanical alloying process for 4 hours and it was measured as 91.27% IACS. In this study, the effects of time, which is one of themechanical alloying process parameters, on the morphology and size of the particles, the microstructure and physical and mechanicalproperties of the compact material were determined.
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
  • Cross-linking of PVC by Various Lengths of PEG via “Click”
           Chemistry

    • Authors: Nilgün ASAN; Temel ÖZTÜRK, Hasibe KUDU, Ergül MEYVACI, Efkan ÇATIKER
      Abstract: Cross-linked poly(polyvinyl chloride) (c-PVC) was synthesized by “click” reaction of polyvinyl chloride with azido pendant group(PVC-N3) and dipropargyllated polyethylene glycol (dp-PEG). For this purpose, dp-PEGs were obtained from polyethylene glycolswith different molecular weights (400 Da, 600 Da, 1000 Da, 1500 Da, 2000 Da, 3000 Da, and 10000 Da) via treatment withpropargyl chloride. PVC-N3 was synthesized through the substitution reaction between the pendant chloride on the PVC chainsand azide ion. By using PVC-N3 and dp-PEGs with various lengths, c-PVCs with various degrees of cross-linking was obtained.The characterization of the PVC-N3, dp-PEG and c-PVC were performed using Fourier transform infrared spectroscopy, nuclearmagnetic resonance spectroscopy, thermogravimetric analysis, scanning electron microscopy and elemental analysis. Degrees ofswelling of c-PVCs with different cross-linking densities in N,N-dimethylformamide were determined by quantitative measurements
      PubDate: Wed, 01 Jun 2022 00:00:00 +030
       
 
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