986 research outputs found

    Science mapping research on educational leadership and management in Turkey : a bibliometric review of international publications

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    Abstract: Over the past two decades, there have been significant efforts to investigate knowledge produc-tion in the field of educational leadership and management (EDLM) in non-Western contexts. Consistent with this effort, the present paper aims to identify the contribution of Turkish scholars to the international EDLM literature. More specifically, the review examined the volume, jour-nals, authors, types of papers, most frequently used keywords, citation impact, and co-citation networks of papers associated with Turkish EDLM scholars. Bibliometric methods were em-ployed to examine 313 papers published by Turkish scholars in internationally recognized jour-nals. The results show that while Turkish EDLM scholars have predominantly published in Tur-key-based journals, there has also been a substantial increase in the number of papers published in international journals in recent years. This literature is largely empirical with topical foci con-centrated on issues surrounding school leadership and organizational behavior. Author co-citation analysis identified three main Schools of Thought in the Turkish literature: Leadership for Learning, Leading Teachers, Administrative Behavior and Effects in Turkey. Several rec-ommendations are made in order to further develop EDLM field in both Turkey and other emerging countries

    Detection of viruses in seeds of some vegetables by reverse transcriptase polymerase chain reaction (RT-PCR)

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    The present study was carried out to detect the presence of Alfalfa mosaic alfamovirus (AMV), cucumber mosaic cucumovirus (CMV), lettuce mosaic potyvirus (LMV), cucumber green mottle mosaic virus (CGMMV), tomato bushy stunt tombusvirus (TBSV), tobacco mosaic tobamovirus (TMV), tomato black ring nepovirus (TBRV) and tomato mosaic tobamovirus (ToMV) in seeds of pepper, tomato, cucumber and lettuce which are essential for human nutrition and seed production in Turkey. 50 seed samples for each vegetable obtained from various foundations and farmers were tested by reverse transcriptase polymerase chain reaction (RT-PCR) and double-antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) was conducted to compare the results. Besides, two total nucleic acid (TNA) extraction methods and a commercial RNA purification kit was compared to get high quality RNA for optimized RT-PCR. Purified total RNA extracts were used as template for cDNA synthesis, PCR products were analyzed by gel electrophoresis, and visualized by ethidium bromide staining. As a result of all, the optimum TNA extraction method was silica capture which is practical and easy to use for getting viral agents from tested vegetable seeds. RT-PCR was found rapid and sensitive in detecting viruses in seeds of vegetables when compared to DAS-ELISA. This study shows that RT-PCR can be successfully applied in certification programs and quarantine tests of vegetable seeds.Keywords: Seed, reverse transcriptase polymerase chain reaction (RT-PCR), total nucleic acid (TNA) extraction, optimizationAfrican Journal of Biotechnology Vol. 12(25), pp. 3891-389

    Biomolecular Corona Associated with Nanostructures: The Potentially Disruptive Role of Raman Microscopy

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    When nanostructures and other materials are exposed to biological fluids, they are immediately covered by a layer of biological molecules, which is typically referred to as a “biomolecular corona” (BC). This represents the first component of a material that interacts with biological systems, so characterizing the composition and the dynamic evolution of BC is essential for predicting the interactions of materials and living organisms. This review provides an analysis of current BC characterization techniques, with particular attention to nanostructures involved in biomedical applications. The influence on cell–nanostructure interactions is assessed and the advantages and limitations of each technique are discussed and compared. An in-depth analysis of Raman microscopy, a relatively unexploited tool with great potential in the characterization of BC, is then conducted. Raman microscopy can be used to analyze a vast amount of specimens without the need for staining, and can provide analysis on a spatial scale of hundreds of nanometers: it may thus represent a potentially disruptive tool for the characterization of BC, as it overcomes many of the limitations posed by current techniques

    Growth and feed utilization of goldfish (Carassius auratus) fed graded levels of brewers yeast (Saccharomyces cerevisiae)

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    In this study, a feeding trial was conducted to examine the potential of replacing fish meal with brewers yeast in practical diet of goldfish (Carassius auratus). Five isoproteic (37% CP) and isocaloric (3350 kcal/kg) diets were formulated to contain graded levels of brewers yeast. Fish meal protein was replaced by 0%, 15%, 25%, 35%, and 45% of yeast. Each diet was randomly allocated to triplicate groups of 20 fish (initial average weight of 0.56 g fish^-1) in glass aquarium (65L). Fish were fed three times per day to apparent satiation for 84 days. At the end of the experiment, weight gain, specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), condition factor (CF), survival rate (SR), hepatosomatic indices (HSI) and body composition of goldfish fry were determined. According to the results, weight gain, SGR, FCR and PER of fish fed the diet including yeast replaced 35% of the fish meal were better than those of fish fed the other diets. There were no significant differences in SR and HSI values among fish fed diets (p>0.05). However, CF among fish fed the experimental diets was significantly different (p>0.05). Whole body composition was similar among fish fed different diets. The optimal replacement level of fishmeal protein by brewers yeast was determined by second-order polynomial regression to be (y= 2, 2237- 0,0004x^2 + 0,0279x; R² = 0,9977) 34.875%, on the basis of SGR

    Effect of the deposition time on optical and electrical properties of semiconductor ZnS thin films prepared by chemical bath deposition

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    Semiconductor ZnS thin films have been deposited by a chemical bath deposition (CBD) on a glass substrate at 80 °C with different deposition time (4, 6 and 8 h). The films have been further studied in order to determine the change in optical and electrical properties as a function of deposition time. The film thicknesses have been calculated between 210–1375 nm by using gravimetrical analysis. The optical properties of ZnS thin films have been determined by transmittance (%T) and absorbance (A) measurements by UV-Vis spectroscopy operated wavelength range between 300 and 1100 nm at room temperature. The optical transmittance values of ZnS thin films in the visible region of the electromagnetic spectrum have been found to be between 51–90%. The calculations indicate that the refractive index (n) in the visible region is between 1.40 and 2.45. The optical band gaps (Eg) of thin films have been calculated between 3.61–3.88 eV while the band edge sharpness values (B) are varied between 6.95×109–8.96×1010 eV/cm2. The specific resistivity values (ρ) of the films are found to be between 1.08×105–1.01×106 Ω·cm and exhibit an n-type conductivity by Hall measurement

    CMS Sensitivity to Dijet Resonances

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    We estimate CMS sensitivity to narrow resonances in the dijet final state. The generic signal shape and QCD background are presented as a function of dijet mass for jet pseudorapidity in the region abs(eta)<1. Statistical and systematic uncertainties are estimated for integrated luminosities of 100 pb^-1, 1 fb^-1, and 10 fb^-1 and a realistic trigger table including multiple thresholds and prescales for jets. The cross section for a dijet resonance that CMS can expect to discovery at 5 sigma significance or exclude at 95% confidence level is presented. We compare these cross section sensitivities with the expected cross section from models of excited quarks, axigluons, colorons, E6 diquarks, color octet technirhos, Wprime, Zprime, and Randall-Sundrum gravitons to determine the masses for which we expect to be able to discover or to exclude these models

    Superparamagnetic iron oxide nanoparticles for magnetic hyperthermia: recent advancements, molecular effects, and future directions in the omics era

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    Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted attention in the biomedical field thanks to their ability to prompt hyperthermia in response to an alternated magnetic field. Hyperthermia is well known for inducing cell death, in particular in tumour cells, which seem to have a higher sensitivity to temperature increases. For this reason, hyperthermia has been recommended as a therapeutic tool against cancer. Despite the potentialities of this approach, little is still known about the effects provoked by magnetic hyperthermia at the molecular level, and about the particular cell death mechanisms that are activated. Nevertheless, in-depth knowledge of this aspect would allow improvement of therapeutic outcomes and favour clinical translation. Moreover, in the last few decades, a lot of effort has been put into finding an effective delivery strategy that could improve SPION biodistribution and localisation at the action site. The aim of this review is to provide a general outline of magnetic hyperthermia, focusing on iron oxide nanoparticles and their interactions with magnetic fields, as well as on new strategies to efficiently deliver them to the target site, and on recent in vitro and in vivo studies proposing possible cell death pathways activated by the treatment. We will also cover their current clinical status, and discuss the contributions of omics in understanding molecular interactions between iron oxide nanoparticles and the biological environment

    On the relative importance of monetary transmission channels in Turkey

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    The main objective of this study is to provide additional evidence on the operation and relative importance of monetary transmission channels in Turkey. The results of the VAR analysis conducted using monthly data between January 2004 and November 2013 suggest that the traditional channels of interest rates, exchange rates, and credit do work in Turkish economy. However, the most striking finding of the study is the relative importance of exchange rate channel in the transmission of monetary policy decision into real economy. Variance decomposition analysis shows that the explained variance by real effective exchange rates is higher for all variables as compared to the variance explained by interest rates. However, interest rates seem to be still a useful tool to manage monetary policy given its role in controlling the changes in exchange rates. The granger causality analysis points into the fact that while interest rates have a role in leading the volatility of exchange rates, exchange rates have an impact on foreign debt holdings of banks and credit growth. On the other hand, foreign debt positions of banks and other sector firms together with credit growth granger causes industrial production. The study has some remarkable ramifications in terms of monetary policy design

    Micro-Analytical Data of Au Mineralization at Atud Gold Deposit, Eastern Desert, Egypt

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    Atud gold deposits located at the central part of the Egyptian Eastern Desert of Egypt. It represents the vein-type gold mineralization at the Arabian-Nubian Shield in North Africa. Furthermore, this Au mineralization was closely associated with intense hydrothermal alteration haloes along the NW-SE brittle-ductile shear zone at the mined area. This study reports new data about the mineral chemistry of the hydrothermal and metamorphic minerals as well as the geothermobarometry of the metamorphism and determines the paragenetic interrelationship between Au-bearing sulfides and gangue minerals in Atud gold mine by using the electron microprobe analyses (EMPA). These analyses revealed that the ore minerals associated with gold mineralization are arsenopyrite, pyrite, chalcopyrite, sphalerite, pyrrhotite, tetrahedrite and gersdorffite-cobaltite. Also, the gold is highly associated with arsenopyrite and As-bearing pyrite as well as sphalerite with an average ~70 wt.% Au (+26 wt.% Ag) whereas it occurred either as disseminated grains or along microfractures of arsenopyrite and pyrite in altered wallrocks and mineralized quartz veins. Arsenopyrite occurs as individual rhombic or prismatic zoned grains disseminated in the quartz veins and wallrock and is intergrown with euhedral arsenian pyrite (with ~2 atom % As). Pyrite is As-bearing pyrite that occurs as disseminated subhedral or anhedral zoned grains replacing by chalcopyrite in some samples. Inclusions of sphalerite and pyrrhotite are common in the large pyrite grains. Secondary minerals such as sericite, calcite, chlorite and albite are disseminated either in altered wallrocks or in quartz veins. Sericite is the main secondary and alteration mineral associated with Au-bearing sulfides and calcite. Electron microprobe data of the sericite show that its muscovite component is high in all analyzed flakes (XMs= an average 0.89) and the phengite content (Mg+Fe a.p.f.u.) varies from 0.10 to 0.55 and from 0.13 to 0.29 in wallrocks and mineralized veins respectively. Carbonate occurs either as thin veinlets or disseminated grains in the mineralized quartz vein and/or the wallrocks. It has higher amount of calcite (CaCO3) and low amount of MgCO3 as well as FeCO3 in the wallrocks relative to the quartz veins. Chlorite flakes are associated with arsenopyrite and their electron probe data revealed that they are generally Fe-rich composition (FeOt 20.64–20.10 wt.%) and their composition is clinochlore either pycnochlorite or ripidolite with Al (iv) = 2.30-2.36 pfu and 2.41-2.51 pfu and with narrow range of estimated formation temperatures are (289–295°C) and (301-312°C) for pycnochlorite and ripidolite respectively. Albite is accompanied with chlorite with an Ab content is high in all analyzed samples (Ab= 95.08-99.20)

    Recursive Partitioning Analysis of Mediastinal N2 Lymph Node Involvement with Selected Biological Markers in Operable Non-small Cell Lung Cancer: A Correlative Study

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    Background: Expressions of various biomarkers in non-small cell lung cancer (NSCLC) have been linked with the prognosis and involvement of mediastinal lymph nodes.Methods: In this study, we utilized recursive partitioning analysis (RPA) by using P53, c-erb-B2, and P-glycoprotein (PGP) expressions evaluated by immunohistochemistry to estimate retrospectively the likelihood of the occult N2 mediastinal lymph node involvement in patients with operable NSCLC.Results: In univariate tests, immunohistochemical staining of the primary tumor for these 3 markers in 61 patients undergoing surgery revealed no direct relationship with the N2 involvement. However, RPA demonstrated in patients aged 75 and with 4 mediastinal lymph nodes removed that, high PGP expression frequency (20%) predicted an increased likelihood of the N2 involvement (46.7%, R2 = 0.25). Univariate nominal logistic regression analysis revealed that RPA group affiliation, and the number of mediastinal lymph nodes resected (logarithmic transformation) were associated with the metastasis to N2 lymph nodes (χ2 = 17.59, p = 0.0005, and χ2 = 2.40, p = 0.0654, respectively). Multivariate analysis confirmed that only RPA group affiliation predicted the N2 involvement (χ2 = 14.63, p = 0.0022).Conclusion: This study shows for the first time that PGP expression of the primary tumor may help to predict the occult N2 mediastinal lymph node involvement in NSCLC. Thus, further research is required to understand whether PGP expression may aid in the decision process for preoperative mediastinoscopy
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