Osmaniye Korkut Ata University Academic Repository
Not a member yet
5726 research outputs found
Sort by
Bioactivity of the Gray Knight Mushroom Tricholoma terreum (Agaricomycetes): Antioxidant, Antiproliferative, and Enzyme Inhibition Potential
No full textThis study investigated the antioxidant, antiproliferative activities and enzyme inhibition potential of Tricholoma terreum (Schaeff.) P. Kumm., a common mushroom species. T. terreum extracts were obtained using ethanol and methanol solvents and tested for their bioactivity. Antioxidant activity was evaluated using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays with moderate activity observed. The ethanol extract showed values of 46.637 +/- 2.146 mg Trolox equivalents (TE)/g for DPPH and 60.683 +/- 1.530 mg TE/g for FRAP, and the methanol extract showed values of 30.987 +/- 1.298 mg TE/g for DPPH and 149.153 +/- 1.290 mg TE/g for FRAP. Additionally, total antioxidant status of both extracts was measured and values were determined as 2.696 +/- 0.032 mmoL/L for ethanol extract and 2.302 +/- 0.040 mmoL/L for methanol extract. Total oxidant status was also evaluated and values were 10.995 +/- 0.170 mu moL/L for ethanol extract and 12.483 +/- 0.213 mu moL/L for methanol extract. Anticholinesterase activity was evaluated by inhibition of acetylcholinesterase and butyrylcholinesterase enzymes and IC50 values were obtained as 58.06 +/- 1.21 mu g/mL and 77.68 +/- 1.23 mu g/mL for ethanol extract and 67.97 +/- 1.04 mu g/mL and 84.85 +/- 0.88 mu g/mL for methanol extract, respectively. In addition, inhibition of amylase and alpha-glucosidase was determined as ethanol extract showed 0.88 +/- 0.05 mmol acarbose equivalents (ACAE)/g for alpha-amylase and 1.39 +/- 0.02 mmol ACAE/g for alpha-glucosidase, while methanol extract showed 0.36 +/- 0.02 mmol ACAE/g and 0.75 +/- 0.03 mmol ACAE/g, respectively. Furthermore, antiproliferative activity was evaluated using MTT assay on cancer cell lines and ethanol extract showed significant inhibition indicating potential anticancer properties. These results suggest that T. terreum contains bioactive compounds with significant antioxidant, enzyme inhibition potential and antiproliferative activities and understanding its oxidative stress potential suggests its therapeutic applications in the treatment of neurodegenerative diseases, cancer and oxidative stress-related disorders
Characterization of novel fibers extracted from Rumex obtusifolius L. plant for potential composite applications
No full textIn this study novel natural fibers were extracted from Rumex obtusifolius L. Extracted fibers were dried for further analysis. The chemical composition was analyzed, revealing the following fiber contents: cellulose at 63.52 +/- 1.51 %, hemicellulose at 27.15 +/- 0.72 %, and lignin at 9.35 +/- 0.57 %. Thermal behavior of the fibers was investigated by using thermogravimetric and derivative thermogravimetric analyses (TG and DTG) and it was found that fibers were thermally stable up to 237.55 degrees C (Tonset) and maximum degradation temperature (Tmax) was determined as 354.67 degrees C. Fiber diameter was varied in range of 226-539 mu m and density was measured as 1.12 +/- 0.74 g cm-3. The crystalline structure of the fibers was examined through X-ray diffraction (XRD) analysis, and the crystallinity index (CI) and crystallite size (CS) were determined based on the corresponding diffraction patterns. CI and CS values were determined as 69.81 % and 3.08 nm, respectively. The mechanical properties of the fibers were evaluated using a single fiber tensile testing method. The measured values for tensile strength, elastic modulus, and strain at break were 192.81 +/- 43.33 MPa, 14.56 +/- 3.27 GPa, and 1.45 +/- 0.43 %, respectively. Result showed that the R. obtusifolius L. fibers are suitable for composite applications as reinforcement material
Fictional representation of women's identity in Duygu Asena's novels
Get PDF21. yüzyıl Türk edebiyatında toplumsal cinsiyet temelli meseleleri odağına alan yazarlar arasında Duygu Asena, ayrı bir yerde konumlanmaktadır. Edebiyat hayatına gazetecilikle başlayan Asena, özellikle kadınların yaşadığı eşitsizlikleri görünür kılmak amacıyla kaleme aldığı romanlarıyla geniş kitlelere ulaşmıştır. Feminist bir perspektifle şekillenen bu eserlerde, bireysel öyküler aracılığıyla ataerkil yapının kadınlar üzerindeki baskısı sorgulanırken, okurun farkındalık düzeyini artırmak hedeflenmiştir. Edebi estetikten çok, düşünsel bir dönüşüm yaratma amacı güden Asena, sanatı bir bilinç uyandırma aracı olarak değerlendirmiştir. Bu yönüyle, sadece bir yazar değil; aynı zamanda kadın hareketinin kültürel bir temsilcisi olarak da kabul edilmektedir. Toplumsal sorunları edebiyatın imkânlarıyla tartışmaya açması, onu çağdaş Türk edebiyatında özgün ve etkili bir ses hâline getirmiştir. Bu tez çalışmasında, Duygu Asena'nın edebi üretiminin temelini oluşturan altı romanında (Kadının Adı Yok, Aslında Aşk da Yok, Aynada Aşk Vardı, Aslında Özgürsün, Aşk Gidiyorum Demez, Paramparça) toplumsal cinsiyet eşitsizliği ve ataerkil düzenin kadın bireyler üzerindeki etkileri ele alınmıştır. Asena'nın romanları, yalnızca bireysel kadın deneyimlerini değil, aynı zamanda kadınların toplumsal konumlarını belirleyen yapısal eşitsizlikleri de görünür kılma amacı taşır. Her bir eserde, erkek egemen toplumun farklı katmanlardaki baskı mekanizmaları -aile, evlilik, iş yaşamı, aşk ilişkileri ve bireysel kimlik inşası gibi alanlarda- eleştirel bir bakış açısıyla sorgulanır. Bu bağlamda Duygu Asena'nın anlatıları, ataerkil ideolojinin kadın yaşamlarını nasıl şekillendirdiğini açığa çıkartırken; kadın karakterlerin yaşadığı içsel çatışmalar, dışsal baskılarla birleşerek cinsiyet temelli eşitsizliklerin derinliğini gözler önüne serer. Yazarın romanlarında çizdiği kadın figürleri, geleneksel kalıplara sığmayan, çoğu zaman mevcut düzene başkaldıran ve kendi kimliklerini inşa etmeye çalışan bireylerdir. Dolayısıyla, bu eserler sadece edebi metinler olarak değil aynı zamanda Türkiye'deki toplumsal cinsiyet ilişkilerini sorgulayan kültürel belgeler olarak da değerlendirilmiştir. Bu çalışmamızda, feminist yazarlar arasında yer alan Duygu Asena'nın Kadının Adı Yok, Aslında Aşk da Yok, Aynada Aşk Vardı, Aslında Özgürsün, Aşk Gidiyorum Demez ve Paramparça adlı romanlarında yer alan kadınlar, roman kurgusunda üstlendiği fonksiyon bakımından değerlendirilecektir.Duygu Asena, who is the one of authors who focus on social women issues is positioned with different way in 21st Century Turkish Literature. Duygu Asena, who started his literary career as journalist reached huge populace with her novels written in order to demonstrate inequality of women. It is aimed to increase awareness of readership as it's query the oppression of patriarchal via personel stories in these pieces written through feminist perspective. Duygu Asena who purposes intellectual conversion evaluated the fiction as raising awareness tool. She is accepted a cultural representative of feminism but an author from this aspect. Bringing into question the communal issues with possibilities of literary made her efficient and authentic voice in Turkish Literary. It was discussed in the context of effects communal gender inequality and patriarchal on women with Duygu Asena's six novels (Kadının Adı Yok, Aslında Aşk da Yok, Aynada Aşk Vardı, Aslında Özgürsün, Aşk Gidiyorum Demez, Paramparça), in this thesis study. Asena's novels aims to make visible structural inequalities which specify the social statue of women not only personal woman experiment. In each pieces, the oppressive mechanisms (in areas such as family, marriage, busines, relationships and individual identity construction, etc...) of the male-dominated society at different levels are questioned from a critical perspective. The internal conflicts experienced by female characters combine with external pressures to reveal the depth of gender-based injustices when Duygu Asena's narratives reveal how patriarchal ideology shapes women's lives. The female figures depicted in the author's novels are individuals who do not fit into traditional molds, often rebel against the existing order and try to build their own identities. Therefore, these works were evaluated not only as literary texts but also as cultural documents that question gender relations in Turkey. In this study, the women depicted in the novels (Kadının Adı Yok, Aslında Aşk da Yok, Aynada Aşk Vardı, Aslında Özgürsün, Aşk Gidiyorum Demez and Paramparça) by feminist author Duygu Asena will be examined in terms of the functions they fulfill within the narrative structure
Asprosin-induced alterations in female rat puberty and reproductive hormonal profiles
No full textObjectiveTo investigate the comprehensive effects of daily chronic asprosin administration on various pubertal and reproductive parameters in female rats. This study aims to elucidate the role of asprosin in regulating the onset of puberty and its influence on hormonal profiles and ovarian histology.MethodsAsprosin was administered intraperitoneally (i.p.) at a dose of 500 ng/kg daily for eight weeks. Hormonal assays and histological analyses were performed to evaluate the effects of asprosin on the onset of puberty and reproductive function.ResultsDaily chronic administration of asprosin accelerated the onset of the first oestrus. Hormonal assays revealed significant elevations in serum levels of Follicle-Stimulating Hormone (FSH) and Oestradiol (E2), while Inhibin B levels decreased. Histological evaluations demonstrated an increased number of primary and secondary follicles in ovarian tissue, without affecting primordial follicle counts or reproductive organ weights.ConclusionsRole of adipokines in regulating puberty and reproductive function has increasingly gained recognition. This study aimed to provide the first comprehensive examination of the effects of daily chronic asprosin administration on pubertal and reproductive parameters in female rats. Utilising hormonal assays and histological analyses, asprosin was administered intraperitoneally (i.p.) at a dose of 500 ng/kg, daily, for eight weeks. Our findings revealed that daily chronic administration of asprosin accelerated the onset of the first oestrus. Hormonal assays showed significant elevations in serum levels of Follicle-Stimulating Hormone (FSH) and Oestradiol (E2), while Inhibin B levels decreased. Histological evaluations demonstrated an increased number of primary and secondary follicles in ovarian tissue, without affecting primordial follicle counts or reproductive organ weights. These results provide new insights into asprosin's role in advancing the age of first oestrus and modulating hormonal profiles, thereby offering potential benefits to the female reproductive system.The Scientific and Technological Research Council of Turkey [G O]E K, I S, B Y, and H K designed and supervised the study. Z D O, M R O, T Y, G O and A O conducted all animal experiments. N K T performed the histological analysis. Z D O, S U B, O Z, A U conducted all hormone measurements. Z D O, M R O, F T, A Y analyzed, and interpreted the data. E K wrote the manuscript, and all authors read and approved the final version of the manuscript
Optimization of 3D printing parameters for enhanced tensile properties in continuous carbon fiber reinforced PLA composites
No full textIn this study, the effect of 3D printing process parameters, specifically line width and layer thickness, on the tensile properties of continuous carbon fiber-reinforced PLA composites fabricated via the Fused Filament Fabrication (FFF) method was investigated. The incorporation of continuous carbon fibers into the PLA matrix aims to enhance the mechanical performance of the printed composites, overcoming the inherent limitations of polymer-based additive manufacturing. The Taguchi method was employed to optimize the process parameters, enabling a systematic evaluation of their influence on tensile strength. An L9 orthogonal array was used to design the experiments, and the Signal-to-Noise (S/N) ratio was analyzed to determine the optimal parameter combination. The results demonstrate that line width and layer thickness significantly affect the tensile performance of printed composites, with narrower line widths (1.0 mm) and thinner layers (0.2 mm) yielding the highest tensile strength (291.3 MPa). Statistical analysis using Analysis of Variance (ANOVA) revealed that line width contributes 58.65% to the overall mechanical performance, making it the most influential factor, followed by layer thickness (33.55%). Microstructural analyses further confirmed that optimized printing parameters improve fiber alignment, enhance interlayer bonding, and minimize void formation. These findings highlight the crucial role of process optimization in maximizing the mechanical properties of FFF-printed continuous carbon fiber reinforced polymer (CFRP) composites, offering insights into achieving high-performance and lightweight structural components
Single and Multi-Objective Optimization of the Red Pine Mushroom Lactarius deliciosus (Agaricomycetes) Extraction Conditions Using Artificial Intelligence Methods and Biological Activities of Optimized Extracts
No full textIn this study, the biological activities of Lactarius deliciosus were determined. Experimental studies were carried out using a soxhlet device, in the range of 40-70 degrees C extraction temperature, 3-9 h extraction time and 0.5-2 mg/ ml extraction conditions. A total of 64 different extracts were obtained using four different values of each variable and the total antioxidant status (TAS) and total oxidant status (TOS) values of these extracts were determined. The obtained data were modeled using artificial neural networks (ANN). Both single-objective and multi-objective optimization processes were performed using the best ANN model selected among the established models. Single-objective optimization was performed with genetic algorithm (GA), and multi-objective optimization was performed using the Non-Dominated Sorting Genetic Algorithm (NSGA-II) algorithm. Extracts obtained from the extraction conditions suggested by the optimization algorithms were used for biological activities. As a result of the analyzes, TAS values of the single-objective optimization extract (1st) and multi-objective optimization extract (2nd) prepared under optimum conditions of the mushroom were determined as 7.468 +/- 0.055 and 6.128 +/- 0.049 mmol/L, TOS values were 13.161 +/- 0.168 and 10.056 +/- 0.106 mu mol/L and OSI values were 0.176 +/- 0.003 and 0.164 +/- 0.003, respectively. It was found to be effective against bacterial and fungal strains at concentrations of 50-200 mu g/mL. In addition, mushroom extracts were found to have strong cytotoxic effects against A549 cancer cell line. Acetylcholinesterase activity of the 1st and 2nd extracts of the mushroom were determined as 24.80 +/- 0.82 and 32.71 +/- 0.91 mu g/mL, butyrylcholinesterase activity was determined as 51.24 +/- 0.80 and 57.10 +/- 0.51 mu g/mL, respectively. In our study, it was determined that L. deliciosus extracts obtained under optimum conditions had strong biological activities.Scientific and Technological Research Council of Turkiye [TUBITAK-2218, 1929B012200173]This research was funded by the Scientific and Technological Research Council of Turkiye (TUBITAK-2218) (Grant No. 1929B012200173)
Synthesis, Characterization, and Theoretical Modeling of 2D Molybdenum Boride (MBene) for All Solid-State Flexible Interdigitated Supercapacitor Application
No full textRecently, two-dimensional transition metal borides (2D MBenes) have demonstrated advanced physical, mechanical, and electrochemical performance; however, there are fewer studies in the literature. In particular, 2D molybdenum boride (2D MoB), created from molybdenum aluminum boride (MoAlB, MAB phase), is one of the important materials introduced due to its thermodynamically stable structure. Herein, we present the preparation of MoAlB and its chemical exfoliation by employing NaOH and LiF-HCl etching solutions to synthesize 2D MoB MBene nanostructures. It is found that the etching conditions significantly affect the selective extraction of the interlayer Al from the MAB phase in solution, forming 2D MoB MBene nanostructures. The resulting 2D MoB MBene illustrates sheet-like morphology, abundant redox active sites, and moderate textural features, which are critical for electrolyte accumulation and transfer. Powder X-ray Diffraction (PXRD) analysis confirmed the crystallinity and phase purity, while Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) revealed the sheet-like morphology and structural integrity. X-ray Photoelectron Spectroscopy (XPS) was employed to analyze the elemental composition and oxidation states, confirming the successful removal of Al and the formation of MoB MBene. Additionally, Brunauer-Emmett-Teller (BET) surface area analysis provided insights into the porous nature and surface area, which are crucial for electrolyte interactions. The all-solid-state flexible interdigitated supercapacitor (ISSC) device prepared using 10/MoAl1-x B electrode exhibited a good areal capacitance of 20.3 mF/cm2, outstanding cyclic capability with 92% capacitance retention after 1300 cycles, and remarkable flexibility. Last but not least, the Density Functional Theory (DFT) of the optimal MoB sample was constructed in terms of structural, conductivity, and thermodynamic stability perspectives, which is well-aligned with experimental results. Applying these 2D MoB MBene electrodes as all-solid-state flexible interdigitated electrodes opens a new avenue in supercapacitor technology.T??rkiye Bilimsel ve Teknolojik Arastirma Kurumu [BIDEB 2247-D, 121C217, 24A05SUP2]; Scientific and Technological Research Council of Turkey TUBITAK; National Center for High-Performance Computing (UHEM/ITU)This study was funded by the Scientific and Technological Research Council of Turkey TUBITAK (BIDEB 2247-D) under project number 121C217. Dr. Demir thanks to Bogazici University, BAP with project number 24A05SUP2. C.S. and N.N. thank the National Center for High-Performance Computing (UHEM/ITU) and Tubitak Ulakbim High Performance and Grid Computing Center for providing the computational resources
Investigation of public service motivation levels of employees in institutions affiliated to the ministry of health according to demographic variables: The case of Osmaniye province
Get PDFKamu ve özel sektörde çalışanların neye göre motive oldukları konusu, günümüz tartışma konularından biridir. Kamu çalışanlarının sadece ekonomik ödüllerle harekete geçtiği kanısına karşı alternatif olarak geliştirilen Kamu Hizmeti Motivasyonu(KHM) teorisi, bireylerin toplumsal faydayı ön planda tutan, idealist ve fedakar kişiler olduğunu savunmaktadır. Uluslararası akademik çevrelerde son yıllarda önem kazanan bu kuram, ülkemizde pek tartışılmamıştır. Bu çalışma, bu alandaki güncel çalışmaları özetlemeyi ve sağlık çalışanları üzerinde bir araştırma yaparak teoriyi ülkemiz kamu yönetimi alanında daha fazla tanıtmayı amaçlamaktadır. Bu bağlamda, nicel bir araştırma olan bu çalışmanın amacı Osmaniye ili özelinde Sağlık Bakanlığına bağlı kurumlarda çalışanların bazı demografik değişkenlere göre kamu hizmeti motivasyon düzeylerini analiz etmektir. Katılımcılardan elde edilen veriler SPSS 22.0 istatistik yorum programı aracılığı ile analiz edilerek istatistiksel teknikler kullanılmıştır. Araştırmanın bulgularına göre Levene's testi, T-testi , frekans, Anova testi, Post Hock LSD ve normallik testleri yapılarak istatistiksel olarak yorumlanmaya çalışılmıştır. Yapılan çalışma sonucunda; cinsiyet, medeni durum, çalışan kurum ve gelir değişkenleri ile KHM arasında anlamlı düzeyde bir farklılık olduğu tespit edilmiştir.The question of what motivates employees in the public and private sectors remains a prominent topic of contemporary discourse. As an alternative to the notion that public sector employees are driven solely by economic incentives, the theory of Public Service Motivation (PSM) posits that these individuals are idealistic and altruistic, placing a high value on societal welfare. Although the PSM theory has garnered significant attention in international academic literature in recent years, it has received limited discussion within the context of our country. This study seeks to both synthesize recent scholarly contributions in this field and promote greater recognition of the theory within the domain of public administration in our national context by conducting empirical research among healthcare professionals. In this context, the aim of this quantitative study is to analyze the public service motivation levels of employees working in institutions affiliated with the Ministry of Health in the province of Osmaniye, based on certain demographic variables. The data obtained from participants were analyzed using statistical techniques through the SPSS 22.0 statistical package program. According to the study findings, statistical analyses including Levene's test, t-test, frequency analysis, ANOVA test, Post Hoc LSD, and normality tests were conducted for interpretation. The results revealed statistically significant differences in PSM levels based on gender, marital status, employing institution, and income variables
Caregiving experiences of Turkish intensive care unit nurses who survived in the most destructive double earthquake of the century: A qualitative study
No full textBackgroundTurkey has been exposed to many devastating earthquakes in recent years. Considering that nurses are on the front lines of responding to disasters, they need to be prepared at all times. In the literature review, it was seen that despite the roles of intensive care nurses in disasters, their experiences in caring for earthquake victims have not been adequately researched.AimThis study aims to investigate the experiences of intensive care nurses during the double earthquake in Turkey in 2023.Study DesignThis descriptive qualitative research was conducted with 11 intensive care nurses working in the double earthquake in Turkey in 2023. Snowball sampling was used to select participants. Data were collected through face-to-face semi-structured interviews. Interviews were continued until data saturation was reached.ResultsAs part of the analysis of the interviews, the nurses' experiences were grouped under four main themes covering 10 sub-themes-'Continuing care despite difficulties', 'Staying in a dilemma', 'Two faces of the earthquake' and 'The need for perfect planning kneaded with experience.'ConclusionThe main source of the difficulties and dilemmas experienced is the obligation of nurses who experienced the earthquake to continue their profession. Still, continuity of care was maintained and nurses drew positive conclusions from the negativity.Relevance to Clinical PracticeConsidering the positive and negative effects of the earthquake, intensive care nurses should be both professionally and psychologically empowered, organizational planning should be conducted as soon as possible and their functionality should be tested through drills
INVESTIGATION OF THE EFFECTS OF PROCESS PARAMETERS ON MACHINING PERFORMANCE IN LASER CUTTING OF 3D-PRINTED PLA
No full textIn the current research, the influences of process parameters on surface roughness and kerf width in CO₂ laser cutting of PLA plates produced by the fused filament fabrication method were experimentally investigated. Laser cutting was performed using three plate thicknesses (2, 3, and 4 mm), three cutting speeds (3, 6, and 9 mm/s), and three laser power levels (90, 95, and 100 W). Surface roughness was determined with a surface roughness tester, and kerf widths were evaluated using a digital microscope. The findings indicate that higher cutting speeds and lower laser power lead to a reduction in both surface roughness and kerf width. Higher cutting speeds combined with lower laser power decreased the thermal effect during cutting by reducing the interaction between the laser and material, resulting in lower surface roughness and narrower kerf width. The effect of plate thickness on surface roughness and kerf width was complex, varying with cutting speed and laser power. The lowest surface roughness (0.951 µm) and kerf width (0.793 mm) values were achieved with a plate thickness of 3 mm, a cutting speed of 9 mm/s, and a laser power of 90 W. This study provides valuable insights into how laser cutting parameters affect the surface quality and dimensional accuracy of PLA plates, contributing to quality improvements in industrial applications. The results highlight the essential influence of cutting speed and laser power on managing surface roughness and kerf width, thus aiding in optimizing the process