Yazarlar
- Bayram, Sinan(7)
- Dertli, Enes(7)
- Kaya, Yunus(7)
- Şahin, Engin(6)
- Ayata, Ümit(5)
- Kutlu, Naciye(5)
- İspirli, Hümeyra(5)
- Can, Zehra(4)
- Ertugrul, Mehmet(4)
- Gökçe, H.S.(4)
- Kahveci, Hakan(4)
- Kaya, Metin(4)
- Abdioglu, Murat(3)
- Alım, Bünyamin(3)
- Cebeci, Fatma(3)
- Dirican, Ebubekir(3)
- Ecem Bayram, Nesrin(3)
- Esmer, Yusuf(3)
- Esteves, Bruno(3)
- Hasar, Ugur C.(3)
- Kamiloğlu, Aybike(3)
- Keskin, Merve(3)
- Koçak, Lokman(3)
- Kumar, Manoj(3)
- Mollahasanoglu, Hakki(3)
- Peker, Hüseyin(3)
- Ramahi, Omar M.(3)
- Sarac, Mehmet F.(3)
- Teber, Ahmet(3)
- Yilmaz, Galip(3)
- Çelik, Eyüp(3)
- Öksüzer, N.(3)
- Özdemir, Akın(3)
- Ülker, Ufuk(3)
- Adeleye, Bosede Ngozi(2)
- Adiyaman, Gokhan(2)
- Akman, Onur(2)
- Aksakal, Vecihi(2)
- Akyol Özcan, Kübra(2)
- Alfaqawi, Mona S. S.(2)
Yayınlar
- MakaleYayıncıda açık erişim2023Catecholaminergic and Cholinergic Systems Mediate Beneficial Effect of Vortioxetine on Diabetes-Induced Neuropathic Pain
Turan Yücel, Nazlı; Kandemir, Ümmühan; Üçel, Umut İrfan; Demir Özkay, Ümide; Can, Özgür Devrim
The therapeutic potential of vortioxetine on mechanical hyperalgesia/allodynia was investigated in rats with streptozotocin-induced diabetes, and its possible mechanism of action was elucidated in this study. The obtained findings demonstrated that subacute vortioxetine treatment (5 and 10 mg/kg for 2 weeks) increased the reduced paw-withdrawal thresholds of diabetic rats both in the Randall–Selitto and Dynamic plantar tests. Moreover, the falling latencies of animals did not change in the Rota-rod assessments. These results suggest that vortioxetine administration significantly improved diabetes-induced hyperalgesia and allodynia responses in the rats without affecting their motor coordination. The vortioxetine (5 mg/kg)-induced antihyperalgesic and antiallodynic effects were reversed by AMPT, yohimbine, ICI 118,551, sulpiride and atropine pre-treatments, suggesting the involvement of the catecholaminergic system, α2- and β2-adrenoceptors, D2/3 dopaminergic receptors and cholinergic muscarinic receptors in the exhibited pharmacological activity, respectively. Moreover, the data from the immunohistochemical studies indicated that the inhibition of c-Fos overexpression in dorsal horn neurons also mediates the beneficial effect of this drug. Vortioxetine induced no difference in plasma glucose levels in diabetic rats. If clinical studies confirm these findings, the concomitant beneficial effect of vortioxetine on mood disorders and its neutral activity profile on glycemic control may make it an alternative drug for the treatment of neuropathic pain.
AtıfScopus6WoS4
İncele - MakaleYayıncıda açık erişim2023Determining consumers’ intent to purchase organic foods in emerging market: price perception affect in moderated mediation model
Yilmazel, Sefa Emre
The main purpose of this research is to explore whether consumers’ consciousness of health, environment and food safety concern affect their intention to purchase organic foods through attitude mediation and price perception moderation. In the study, a sample of consumers who buy organic food was determined. 386 data were collected in Turkey. Confirmatory factor analysis made in the Amos 22.0 program and hypothesis tests were carried out in the Process Macro with Model 14. The results indicated that consciousness of health, environment and food safety effect consumers’ organic food attitude positively. Further, consumer attitude towards organic food effect their purchase intention. In addition, price perception show moderating effect on this relationship. Moreover attitude mediation effect (full and partial) has been proven. With this study, a comprehensive model has been revealed for emerging countries regarding the purchase of organic foods. Price perception moderating effect between attitude and purchase intention has been proven.
AtıfScopus8WoS9İncele - MakaleYalnız künye2023Performing trajectory tracking control of an unmanned ground vehicle using fractional order terminal sliding mode controller
Sekban, Hayriye Tuǧba; Başçi, Abdullah
In this paper, fractional order terminal sliding mode control (FOTSMC) method is used for trajectory tracking control performance of an unmanned ground vehicle (UGV). Firstly, a kinematic controller is designed to estimate the linear and angular velocities of the vehicle. Then, a FOTSMC design is carried out to track the vehicle reference velocities. Terminal sliding mode control (TSMC) and sliding mode control (SMC) methods are also used to demonstrate the performance of the proposed controller. The simulation results show that the proposed controller improves the tracking error by about 13% over SMC and 6.146% compared to TSMC.
AtıfScopus3WoS3İncele - MakaleYalnız künye2023Optimizing and investigating durability performance of sandy soils stabilized with alkali activated waste tuff-fly ash mixtures
Yilmaz, Fatih; Kuvat, Ahmet; Kamiloğlu, Hakan Alper
The search for alternative environmentally-friendly materials to Portland cement is increasing its importance in geotechnical engineering as in other fields. In this study, alkali activated waste volcanic tuff (BT) and fly ash (FA) utilized as an alternative to conventional binders. The specific objectives of this paper were to, (1) optimize fly ash, waste tuff and activator content using Response Surface Methodology (RSM), (2) investigate the UCS performance of the optimum amount of alkali-activated fly ash and waste tuff mixtures as a binder in soil stabilization by comparing with various codes, (3) characterize the optimized parameters, (4) examine durability performances of the samples. Optimum binder and activator content and effect of waste tuff on strength characteristics were evaluated statistically with RSM approach. XRF, XRD, FTIR analyses were performed to verify the synthesized alkali activated material in the inner structures of the optimized samples. The durability and mechanical properties of samples stabilized with alkali activated binders against soaking condition, wetting-drying and were investigated. Destructive and non-destructive methods were employed to examine mechanical and durability characteristics. Unconfined compression strength, strength reduction ratio, soil deterioration, and water absorption capacity was taken into account to evaluate durability performances. UCS values of the stabilized samples were compared with limit UCS values suggested by several standards. As a result of the study it was determined that alkali activated waste tuff and fly ash mixture shows significant mechanical and durability performance in soil stabilization, and capable to use as an alternative to conventional non-green binders.
AtıfScopus6WoS4İncele - MakaleYalnız künye2023Cr-substituted nanocrystalline Ni–Co ferrites: tuning dielectric, magnetic, structural, X-band microwave absorption, and characteristic properties
Teber, Ahmet; Sarac, Mehmet F.
The structural, characteristic, dielectric, and magnetic features of Co0.5Ni0.5CrxFe2 − xO4 (0.0 ≤ x≤ 1.0 with a step of 0.2 x-concentration) nanoparticles are prepared via the hydrothermal method. The investigation of characteristics, structural, and magnetic features of the produced nanoparticles are examined through XRD, FT-IR, SEM–EDS, TEM-SAED, and VSM, respectively. AC conductivity and the dielectric investigations are also reported. According to the XRD measurements, all samples have the M-type hexagonal crystal structure nanocrystallites of between 27 and 97 nm. Refined structural parameters using Rietveld analysis are carried out using the TOPAS refinement program. A good match was observed between the diffraction patterns obtained and calculated by Rietveld analysis. Moreover, the morphological analyses indicate that the relatively small spherical structures of Ni–Co ferrites particles can be seen to change from spherical to relatively oval-shaped with increasing chromium content. The results of the FT-IR study show that the spinel structure has formed as predicted because the expected range of absorption bands is present. According to magnetic measurements, Cr-substituted Ni–Co ferrite nanostructures reveal a relatively soft ferromagnetic property. The coercive field (Hc) variation has a propensity to decrease in relation to the Cr-concentration. The electromagnetic constitutive parameters are calculated from measured S-parameters (S11 and S21) using network analyzer and the return losses of the samples are then obtained to determine microwave absorption properties. According to the dielectric and magnetic tangent losses or dissipation factors, both dielectric and magnetic features can mutually reinforce in terms of microwave absorption properties in the X-band. The Cr2O3 impurity peaks obtained by XRD analysis have an effect on the microwave absorption properties. The results of the microwave absorption based on each concentration reveal that there exist electromagnetic wave absorptions between approximately 11 GHz and 12.4 GHz in the X-band. The absorption trend is also towards the Ku-band.
AtıfScopus3WoS3İncele - MakaleYalnız künye2023Socioeconomic status and wellbeing as predictors of students' academic achievement: Evidence from a developing country
Erdem, Cahit; Kaya, Metin
The COVID-19 pandemic has deepened the effects of socioeconomic status (SES) and wellbeing (WB) on students' academic achievement, particularly in developing countries; thus, it becomes necessary to understand the nature of these concurrent relationships. This study aimed to explore the relationships between SES, WB and academic achievement, based on the data from the Programme for International Student Assessment (PISA) in 2018 within the Turkish context. In this cross-sectional study, we used hierarchical multiple linear regression analysis to explore how the independent variables predicted academic achievement in blocks based on data from 6890 students attending 186 schools. The study revealed that the model, including the independent variables, predicted students' achievement in reading, mathematics and science; however, the prediction level of demographic factors and domains of WB were very low, while SES had the highest prediction level. The results offer insights into the predictors of academic achievement and educational inequalities in the context of a developing country.
AtıfScopus35WoS28İncele - MakaleYayıncıda açık erişim2023Designing New Model-Based Adaptive Sliding Mode Controllers for Trajectory Tracking Control of an Unmanned Ground Vehicle
Sekban, Hayriye Tugba; Basci, Abdullah
This paper proposes three new dynamic model-based adaptive sliding mode controllers (ASMC) for trajectory tracking control of unmanned ground vehicles (UGV). The controllers combine kinematic and dynamic control to achieve asymptotic stability and finite-time convergence and their stability is verified using the Lyapunov stability theory. The controllers are designed to address the challenges posed by uncertainties in vehicle dynamic parameters and outperform the sliding mode control (SMC) method in trajectory tracking control. The simulation results of the proposed controllers are also discussed in terms of performance metrics. The simulation results show that the controller proposed in rule 1 shows the better performance in terms of trajectory tracking, and then the controllers proposed in rules 2 and 3 have good performances, respectively. In addition, when the simulation results are compared, it is seen that the performance of all three proposed controllers is better than the SMC.
AtıfScopus12WoS10İncele - MakaleYalnız künye2023An Investigation on the Behavior of 3D Steel Frames Under Progressive Collapse Effect Using Nonlinear Dynamic Analysis
Tayfur, Bilal; Daloǧlu, Ayșe T.
In this study, the nonlinear dynamic analysis of steel structures against progressive collapse was examined, and the adequacy and validity of the analysis duration defined in the regulation were investigated. In addition, the effects of the seismic resistance and design against progressive collapse constraints on the structure were investigated. An optimization algorithm was used in order to conduct the iterative process with appropriate sections. The frames were analyzed to perform one cycle as recommended in the UFC, and then the analysis duration was extended until at least five cycles had been completed. When the UFC was considered only, it was observed that while some of the designs were classified as safe within the duration specified in the UFC, the structural integrity was seen to get into danger in the subsequent cycles. When constraints related to seismic effect are also included in the process, it was seen that the threat disappeared for the frames examined. In addition, it was observed that the steel frame resisted progressive collapse scenarios by creating formations like Vierendeel beams.
AtıfScopus1WoS1İncele - MakaleYalnız künye2023Characterisation of dextran AP-27 produced by bee pollen isolate Lactobacillus kunkeei AP-27
Yilmaz, Mustafa T.; İspirli, Hümeyra; Alidrisi, Hassan; Taylan, Osman; Dertli, Enes
An exopolysaccharide (EPS) produced by bee pollen isolate Lactobacillus kunkeei AP-27 was characterised in this study. EPS monomeric composition of strain AP-27 was characterised by High-performance liquid chromatography (HPLC) analysis and glucose was the only sugar in the EPS repeating unit. Structural analysis of glucan AP27 by 1H and 13C Nuclear magnetic resonance (NMR) analysis demonstrated that this glucan was a dextran ((1→6)-linked α-D-glucose units as the main body) consisting very low level of (1 → 4)-linked α-D-glucose units (∼ 0.5 %). Dextran AP-27 had a degradation temperature of 308 °C that revealed its superior thermal strength identified by Thermogravimetric (TGA) and Differential scanning calorimetry (DSC) analysis. The molecular weight of dextran AP-27 was determined to be 25 kDa by Gel Permeation Chromatography (GPC) analysis. Crystallographic properties of dextran AP-27 was determined by X-ray diffraction (XRD) analysis that divulged its amorphous feature. Scanning Electron Microscopy (SEM) analysis was applied for microstructural characterisation of dextran AP-27 which revealed its regular sphere like characteristics. These findings suggest that Lactic Acid Bacteria (LAB) strains from different environments such as bee products can be the source for distinct EPS producer strains.
AtıfScopus9WoS8İncele - MakaleYalnız künye2023A comparison of the associations between bone turnover markers and different sports fields: combat versus team sports
Yıldız, K.; Uzunçakmak, S. Karabulut; Halıcı, Z.; Özçelik, C.; Yazıcı, A.G.
Sedentary life brings risks that include osteoporosis, while physical activity has many benefits for health in general and the skeletal system. Irisin is a hormone-like myokine regulated by mechanical force and it contributes to cortical and trabecular bone mineral density. This study aimed to investigate the effects of different types of sports on bone health by measuring elite athletes’ fibronectin type III domain 5 (FNDC5), N-terminal collagen type I extension propeptide (PINP), and C-terminal cross-linking telopeptide of type I collagen (CTXI) levels. Combat sports athletes, team sports athletes, and sedentary control subjects were enrolled. Serum levels of proteins were measured by ELISA. FNDC5 levels of elite athletes were higher compared to the sedentary controls (P=0.0014). The highest FNDC5 level was measured in wrestlers among all considered groups. The PINP levels of the athletes were also higher than those of the sedentary control group (P=0.1431). The highest PINP level was determined in boxers. The CTXI levels of the athletes were lower than those of the sedentary control (P<0.0001). The lowest CTXI level was seen in boxers. The FNDC5 and PINP levels of combat sports athletes were higher than those of team sports athletes (P=0.0134 and P=0.0262, respectively), while the CTXI levels of combat sports athletes were lower than those of team sports athletes (P<0.0001). Our results indicated that FNDC5, PINP, and CTXI levels are associated with physical activity. The effect of the exercises performed by athletes of specific sports on bone health has not been studied in much detail before. Combining different exercises for athletes of a particular sport may be more beneficial for bone health.
- MakaleYalnız künye2023Yttrium-substituted Co0.5Ni0.5YxFe2-xO4 ferrites as microwave absorbers by investigating structural, magnetic, dielectric, and absorption characteristics
Teber, Ahmet; Sarac, Mehmet F.
The effect of Yttrium Substitution on Co0.5Ni0.5YxFe2- xO4 (0.0 ≤ x ≤ 1.0) Ferrites as Microwave Absorbers was investigated to include structural, magnetic, dielectric and X-band absorption properties. The main objective of this work is to enhance microwave absorption properties of materials with interesting dielectric/magnetic behaviors by doping rare earth element of Yttrium based on transition metals. The hydrothermal method was used to create Yttrium (Y) substituted nanoparticles, and the effects of Y-ion substitution on the characteristics, structural, magnetic features were examined by XRD, FT-IR, SEM-EDS, TEM-SAED, and VSM, respectively. Electromagnetic properties were obtained from microwave scattering parameters measured via a metal-backed transmission line and Nicholson-Ross Weir techniques using a vector network analyzer (VNA) in conjunction with an X-band waveguide set. Return loss (RL) values of the samples were obtained from the electromagnetic constitutive parameters (permittivity and permeability). According to the XRD measurements, hexagonal crystal structure of ferrite and YFeO3 as secondary phase nanocrystal sizes are between 11 and 67 nm. Refined structural parameters using Rietveld analysis are carried out using the TOPAS refinement program. A good match was observed between the diffraction patterns obtained and calculated by Rietveld analysis. Moreover, the morphological analyses indicate that the relatively small spherical structures of Ni-Co ferrites particles can be seen to change from spherical to hexagonal-shaped with increasing yttrium concentration. The results of the FT-IR study show that the spinel structure has formed as predicted because the expected range of absorption bands is present. According to magnetic measurements, the coercivity (Hc) results show a modest increase in porosity as the Y-content rises. The results revealed that the minimum RL value and bandwidth vary significantly with the amount of Yttrium in the mixture, indicating that the obtained structures will be useful for broadband microwave applications.
AtıfScopus10WoS11İncele - MakaleYalnız künye2023Effects of electromagnetic radiation on neurogenesis and gene expression in amniocytes
Uzun, Coşar; Erdal, Nurten; İzci Ay, Özlem; Karakaş, Ümit; Derici Yildırım, Didem; Durukan, Hüseyin; Akdag, Mahmut Berat; Erdal, Mehmet Emin
The aim of the study was to investigate the genetic effects of commonly used radiofrequency on the amniocytes of pregnant women by examining the changes in the expression of genes related to signal transduction and neurogenesis induced by electromagnetic fields of radiofrequencies of 1800 and 2100 MHz by real-time PCR. Upon exposure of the amniocytes to electromagnetic radiation of 2100 MHz at high field strength, the expression levels of genes with important functions in the Wnt signaling pathways as well as neurogenesis-related genes were increased. The findings suggest that radiofrequency at high field strengths can have genotoxic effects during pregnancy.
AtıfScopus1WoS1İncele - MakaleYayıncıda açık erişim2023Face presentation attack detection performances of facial regions with multi-block LBP features
Günay Yılmaz, Asuman; Turhal, Uğur; Nabiyev, Vasif
Biometric recognition systems are frequently used in daily life although they are vulnerable to attacks. Today, especially the increasing use of face authentication systems has made these systems the target of face presentation attacks (FPA). This has increased the need for sensitive systems detecting the FPAs. Recently surgical masks, frequently used due to the pandemic, directly affect the performance of face recognition systems. Researchers design face recognition systems only from the eye region. This motivated us to evaluate the FPA detection performance of the eye region. Based on this, in cases where the whole face is not visible, the FPA detection performance of other parts of the face has also been examined. Therefore, in this study, FPA detection performances of facial regions of wide face, cropped face, eyes, nose, and mouth was investigated. For this purpose, the facial regions were determined and normalized, and texture features were extracted using powerful texture descriptor local binary patterns (LBP) due to its easy computability and low processing complexity. Multi-block LBP features are used to obtain more detailed texture information. Generally uniform LBP patterns are used for feature extraction in the literature. In this study, the FPA detection performances of both uniform LBP patterns and all LBP patterns were investigated. The size of feature vector is reduced by principal component analysis, and real/fake classification is performed with support vector machines. Experimental results on NUAA, CASIA, REPLAY-ATTACK and OULU-NPU datasets show that the use of all patterns increased the performance of FPA detection.
AtıfScopus18WoS11
İncele - MakaleYayıncıda açık erişim2023Socio-economic determinants of environmental degradation: Empirical evidence for the Environmental Kuznets Curve
Gültekin, Ömer Faruk; Sayar, Ramazan; Ari, Yllmaz Onur
The aim of the paper is to examine socio-economic determinants of environmental degradation. The empirical study employs quantile regression which enables separate predictions for different levels of the dependent variable to be made. This study investigated 62 countries from low, middle and some high income countries for 1995-2019. The Environmental Kuznets Curve (EKC) is verified for the aforemented countries in analyzing the relationship between economic growth and carbon emissions using quantile regression. The study also revealed that the schooling rate has a pollution-increasing effect. In addition to the reducing effects of trade openness, democracy, and economic freedom variables on environmental degradation, the opposite effect of life expectancy at birth is observed, increasing environmental degradation. In this context, this paper concluded that the EKC hypothesis is not supported. The government should encourage pollution-reducing policies in low and middle income countries.
AtıfScopus4WoS3İncele - Kitap BölümüYalnız künye2023Isothiocyanates as drug candidates in cancer prevention and treatment
Saylan, Demet; Cebeci, Fatma
Cancer is the second most common cause of death worldwide. Many methods such as surgery, chemotherapy, radiation therapy, etc. are being used for treatment. Most patients have a combination treatment with chemotherapy along with surgery or radiotherapy or both. Chemotherapy kills cancer cells by preventing them from reproducing, growing, and spreading in the body. Recently, safer alternatives to chemotherapy have been discovered and developed, as most of the drugs used in cancer treatment have side effects and a serious impact on patient comfort. As an alternative, the phytochemicals found in daily consumed plants are attractive candidates for clinical/pre-clinical evaluation because of their higher safety. In this context, certain degradation products of glucosinolates (isothiocyanates) are promising agents for cancer prevention and treatment.
- MakaleYalnız künye2023The determinants of non-family employees' turnover intentions in family firms
Yazici, Omer; Memili, Esra; Patel, Pankaj C.; Ramadani, Veland
While research on the organisational behaviour and HRM (i.e., organisational identification, justice, commitment, and turnover intentions) in family business contexts has been advancing, the empirical investigation of non-family employees’ perceptions is still scarce. Drawing upon family business-influenced literature and organisational identification, justice, and commitment theories, we explore the determinants of non-family employees’ turnover intentions. Specifically, we examine the impact of non-family employees’ family firm identification and perceived justice on family firm commitment, in turn affecting turnover intentions. Furthermore, we examine the moderation effects of perceived family influence on these links. Our findings demonstrate that non-family employees’ family firm identification and perceived justice positively affect their family firm commitment, which in turn lowers turnover intentions. While family firm commitment mediates the relationship between family firm identification and turnover intentions, perceived family influence moderates the mediation effects of family firm commitment between family firm identification and turnover intentions. 2023 Inderscience Enterprises Ltd.
AtıfScopus1İncele - MakaleYalnız künye2023Design, synthesis, antioxidant and anticholinesterase activities of novel isonicotinic hydrazide-hydrazone derivatives
Aslanhan, Özlem; Kalay, Erbay; Tokalı, Feyzi Sinan; Can, Zehra; Şahin, Engin
The design and synthesis of hydrazone derivatives are increasing in popularity day by day due to the significant biological activities of this scaffold. In the present study, twelve novel isonicotinic hydrazide-hydrazone analogues were synthesized by the condensation reaction of isonicotinic hydrazide with benzaldehyde possessing sulfonate moiety. The structures of the novel compounds have been characterized in detail using spectroscopic techniques. All compounds have shown inhibitory effects against the AChE enzyme at rates ranging from 21.00 to 59.48%. Among them, compound 5 has exhibited the best inhibitory effect of 59.48% against AChE at a concentration of 0.1 mM. Furthermore, to determine how effective the novel compounds are as antioxidants, FRAP and DPPH studies were also carried out. FRAP values in compounds 1–12 were found to range from 26.989–3415.556 µmol FeSO4.7H2O/mg. They also displayed moderate antioxidant potential in the range of SC50=0.03–87.32 mg/mL compared with the control Trolox (SC50 =0.004) in DPPH radical scavenging activities. It was seen that the AChE inhibition percentages of the compounds were in the range of 23.04–58.10% at 0.1 mM concentration. This is the first research on the synthesis, antioxidant and enzyme inhibition properties of these compounds.
AtıfScopus43WoS37İncele - Kitap BölümüYalnız künye2023Enigmatic secondary metabolites: Microbial melanins and their applications
Narang, Urja; Kurian, Noble K; Bayram, Sinan
Melanin is a biomacromolecule found in all kingdoms of life that ranges from dark brown to black pigment. Eumelanin, allomelanin, neuromelanin, and pheomelanin are all types of melanin. They possess a wide range of bioactive properties, including antioxidant, radioprotective, antimicrobial, antiviral, antiinflammatory, antiproliferative, and photoprotective properties. Melanin has anticancer and antimicrobial properties that make it useful in pharmacology and medicine. In addition, it has applications in cosmetics; to mimic the natural process of these compounds in the skin, many manufacturers have embraced the use of melanin in sunscreens. Furthermore, due to the absorption of ultraviolet rays, mixed electronic-ionic conductivity, and hydration state-dependent electrical properties of melanin, it is used in organic electronics such as solar cells, batteries, and biosensors. This review examines the various functions and applications of this biological pigment, as well as its distinct physicochemical, chemical, bioactive, and anticorrosive properties.
AtıfScopus1İncele - MakaleYayıncıda açık erişim2023Preparation of Eumelanin-Encapsulated Stereocomplex Polylactide Nano/Microparticles for Degradable Biocompatible UV-Shielding Products
Putri, Oceu Dwi; Petchsuk, Atitsa; Buchatip, Suthawan; Supmak, Wilairat; Kaewsaneha, Chariya; Thananukul, Kamonchanok; Nim, Bunthoeun; Bayram, Sinan; Thumanu, Kanjana; Opaprakasit, Pakorn
The role of eumelanin as a natural pigment in protecting human skin from ultraviolet (UV) light has drawn vast interest in the research and industrial community. Encapsulation of the compound by various shell materials has been extensively studied to optimize and prolong its shielding efficiency from UV penetration through the skin. Polylactide (PLA)-based copolymers have been widely used in the encapsulation of various active compounds due to their biocompatibility and biodegradability that facilitate sustained release of the active compounds. In this work, stereocomplex PLA (sc-PLA) derived from mixtures of poly(D-lactide-caprolactone-D-lactide), P(DLA-b-CL-b-DLA), a triblock copolymer with linear poly(L-lactide), and PLLA are employed to encapsulate eumelanin by an oil-in-water emulsion (O/W) technique. The effect of eumelanin distribution in PLA's enantiomers and ultrasonication on the physicochemical properties, encapsulation efficiency, and release behavior of the nano/microparticles were evaluated. The potential application of the resulting particles for sunscreen products was assessed in terms of UV absorbance and in vitro sun protection factor (SPF). The nano/microparticles show a hollow spherical structure, whose size can be controlled by ultrasonication. The distribution of eumelanin and the ultrasonication process play a key role in the growth of sc-PLA and the crystalline structure of the particles. The highest encapsulation efficiency of 46.6% was achieved for sc-PLA2U particles. The high content of eumelanin and the hollow structure with a large surface area lead to improvement in the UV absorbance and sunscreen performance of the particles, as revealed by the increase in the SPF value from 9.7 to 16.5. The materials show high potential for various applications, especially in cosmetic and pharmaceutical fields, as UV-shielding products.
AtıfScopus3WoS3İncele - Kitap BölümüYalnız künye2023Digitalization in management: The case of the metaverse
Battal, Fetullah; Öz, Halil H.
When the historical development of management is examined, it is seen that every age has created a management and organizational structure suitable for its own conditions. Therefore, today, management and organizational structures are experiencing a digital transformation as a necessity of the age. From this point of view, this study was carried out as a conceptual analysis in order to conceptually examine new terms such as digital management, digital transformation, and digital leader that emerged with digitalization in management structures to explain the change in management structures by comparing them with previous management structures and to eliminate the ambiguities about the concept of digitalization. In addition, another aim of this study is to compile explanations in the literature about the metaverse, which is described as a three-dimensional virtual world, and to evaluate the innovations, opportunities, concerns, and criticisms brought by the metaverse application.