Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 15Citation - Scopus: 17Effect of Different Microencapsulating Materials on the Viability of S. Thermophilus Ccm4757 Incorporated Into Dark and Milk Chocolates(Elsevier Ltd., 2021) Öztürk, Burcu; Elvan, Menşure; Özer, Merve; Tellioğlu Harsa, ŞebnemThis study aimed to evaluate the viability and bioaccessibility of Streptococcus thermophilus CCM4757 strain supplemented in dark and milk chocolates during storage period and pass through simulated in vitro gastro-intestinal tract. Microencapsulated and non-microencapsulated S. thermophilus CCM4757 strain added into the chocolates. Emulsion technique was used to microencapsulate cells with various biopolymers; carboxymethylcellulose, pectin, gum arabic, and cellobiose. The microencapsulated S. thermophilus with these coating materials was found to be viable higher than 9 log CFU/g up to 180 days of storage at 4 °C. Microbiological, physicochemical, and sensorial attributes of the chocolates containing microencapsulated and non-microencapsulated S. thermophilus CCM4757 were analyzed. The microencapsulated S. thermophilus showed a good survivability in milk (7.12 log CFU/g) and dark (6.90 log CFU/g) chocolate samples during 180-day storage at 4 °C. Supplementation of S. thermophilus did not affect significantly (P > 0.05) the sensory attributes of the chocolates. The results showed that S. thermophilus CCM4757 exhibited good cell survivability higher than 85% in chocolates under simulated gastro-intestinal fluids. S. thermophilus supplementation into the chocolate protected the viability of cells and did not affect the sensorial characteristics and moisture content of chocolates. The present study demonstrated that the dark and milk chocolates could be used as an important matrix to carry probiotics. © 2021 Elsevier LtdArticle Identification and Visualization of Cell Subgroups in Uncompensated Flow Cytometry Data(Elsevier Ltd., 2020) Güzel, Başak Esin Köktürk; Karaçalı, BilgeWe propose a new method for identification and visualization of cell-sub groups in uncompensated multi-color flow cytometry data. The method combines annealing-based model-free expectation-maximization to identify cell sub-groups and joint diagonalization on clustered data for better visualization. The proposed method was evaluated on a real, publicly available 8-color flow cytometry dataset manually gated beforehand for lymphocytes. The results obtained in three separable scenarios indicate that the method accurately identifies cell subgroups while properly adjusting visualization of identified cell groups by reducing the spectral overlap between the different fluorochrome channels.Article Citation - WoS: 19Citation - Scopus: 19Navigating Cie Space for Efficient Tadf Downconversion Woleds(Elsevier Ltd., 2020) Aksoy, Erkan; Danos, Andrew; Varlıklı, Canan; Monkman, Andrew P.High efficiency orange and green emitting perylene dyes have been synthesized and dispersed in an inert polymer host to form an optical downconversion layer. To avoid dye aggregation and allow controlled colour tuning, this layer was deposited in multiple low-concentration spin-coating steps, directly on top of a high performance blue thermally activated delayed fluorescence (TADF) organic light emitting diode (OLED). The orange downconversion layer partially absorbs the blue OLED emission, while emitting a complementary orange to give white light. However, as energy transfer between the TADF and perylene downconverter is based on emission and reabsorption, absorptive filtering of the blue OLED emission band necessitates the inclusion of an additional green-emitting perylene top-layer to achieve optimal white balance. The optimised white OLED fabricated in this way displayed excellent white colour balance (CIE x, y; 0.33, 0.33) with perfect stability, good colour rendering (CRI 80), and a high maximum efficiency (maximum EQE 17.2%) with minimal losses compared to the base blue OLED. This approach is widely applicable for generating white emission from any kind of blue OLED, and is compatible with a wide range of downconverting dyes and host materials.Article Citation - WoS: 32Citation - Scopus: 33Variation of Structural and Optical Properties of Tio2 Films Prepared by Dc Magnetron Sputtering Method With Annealing Temperature(Elsevier Ltd., 2020) Gürakar, Sibel; Ot, Hakan; Horzum, Şeyda; Serin, TülayTiO2 thin films are deposited by direct current magnetron sputtering method on the silicon and quartz substrates. The effect of annealing temperature on the film properties are analysed by using X-ray diffraction (XRD), Raman scattering, atomic force microscopy (AFM), scanning electron microscopy (SEM) and optical spectroscopy measurements. Raman and XRD results reveal that the crystal structure of the TiO2 film is strongly affected by the annealing temperature. The crystal structure of the coated film is changed from amorphous to anatase structure after annealing at 500 degrees C. Anatase and rutile phases of TiO2 start to coexist after annealing at 800 degrees C. Rutile phases of TiO2 become dominant for film annealed at 900 degrees C. SEM and AFM images uncover that the morphology, grain size and surface roughness of TiO2 films vary with the annealing temperature. The optical band gap decreases from 3.35 to 2.90 eV as the phase transforms from amorphous to rutile.Article Citation - WoS: 8Citation - Scopus: 8Study of Boron Doped Amorphous Silicon Lightly Hydrogenated Prepared by Dc Magnetron Sputtering for Infrared Detectors Applications(Elsevier Ltd., 2020) Ketroussi, K.; Cherfi, R.; Yahia, Seba, H.; Tata, S.; Chabane, L.; Özyüzer, Lütfi; Rahal, A.The objective of this study is to investigate the effect of boron doping concentration on the bolometric properties of lightly hydrogenated amorphous silicon doped with boron (a-Si: H(B)) films. Thin film a-Si: H(B) samples with different boron concentrations are prepared by co-sputtering of boron and silicon at relatively low hydrogen pressure. FTIR analyses show that the intensity of the characteristic peak of the substitutional boron gradually increases with the addition of boron. Increasing in boron concentration affects the bolometric properties of the lightly hydrogenated a-Si: H (B) films, including conductivity at room temperature (?RT) and thermal resistance coefficient (TCR). Indeed, when the boron concentration increases from 1.5 to 43%, ?RT increases from 1.4 10?6 to 2 10?3 ??1 cm?1 while the absolute value of TCR decreases from 3% to 8% K?1, respectively. In addition, lightly hydrogenated a-Si: H (B) films exhibit good thermal stability. We have showed in this study that lightly hydrogenated a-Si: H(B) can be considered as a potential candidate for low-cost, high-performance uncooled micro bolometers. © 2020 Elsevier B.V.Article Citation - WoS: 3Citation - Scopus: 4Lipid Bilayer on Wrinkled-Interfaced Graphene Field Effect Transistor(Elsevier Ltd., 2021) Özkendir İnanç, Dilce; Çelebi, Cem; Yıldız, Ümit HakanThis study describes lipid bilayer-based sensor interface on SiO2 encapsulated graphene field effect transistors (GFET). The SiO2 layer was utilized as a lipid compatible surface that drives bilayer formation. The two types of surface morphologies i) wrinkled morphology by thermal evaporation (TE) and ii) flat morphology by pulsed electron deposition (PED) were obtained. The sensing performance of wrinkled and flat interfaced-GFETs were investigated, pH sensitivity of wrinkled interfaced-GFETs were found to be ten fold larger than the flat ones. The enhanced sensitivity is attributed to thinning of the oxide layer by formation of wrinkles thereby facilitating electrostatic gating on graphene. We foresee that described wrinkled SiO2 interfaced-GFET holds promise as a cell membrane mimicking sensing platform for novel bioelectronic applications. © 2020Data Paper Citation - WoS: 2Citation - Scopus: 3Assessing Museums' Daylighting Adequacy Without Annual Measurement Campaign: Dataset of a Confrontation Between Measured and Simulated Illuminance Values Inside the Cetacean Gallery of the Charterhouse of Calci(Elsevier Ltd., 2020) Leccese, Francesco; Salvadori, Giacomo; Tambellini, Giuseppe; Kazanasmaz, Zehra TuğçeLighting Cultural Heritage is a complex task: light is necessary for the act of seeing, it can even enhance the visual experience [1,2], in addition proper lighting can significantly cut down energy consumptions [3], but on the same time it has detrimental effects on exhibits, especially daylight. In order to safeguard the exhibits from damages, national and international standards provide specific recommendations for exhibits' exposure, based on their photosensitivity category. These recommendations are the annual luminous exposure(LO) and the Maximum Illuminance Level (E-max), museums' curators have to verify that the display lighting conditions comply with the standards. Historical buildings are often converted into museums but, as their original purpose was different, the lighting conditions are often inadequate (e.g. too much uncontrolled daylight), therefore the lighting conditions' adequacy of the space should be assessed [4]. As the name suggest the annual luminous exposure requires an annual monitoring campaign, unfortunately it often happens that exhibits have been exposed incorrectly for prolonged periods, and therefore it is very important to evaluate the need of a fast intervention. In this casuistry a prolonged measurement campaign is not acceptable. Simulations can help running a great number of analysis while reducing the length and expenses of a measurements campaign, however their previsions must be validated. This paper provides the data acquired through measurements and simulations inside the Cetacean Gallery of the Monumental Charterhouse of Calci, near Pisa (Tuscany Region, Italy). The data comprehends horizontal and vertical illuminance measurements, recorded on December the 6th, and simulations run in Grasshopper with the plugins Honeybee+ and Ladybug. The data are related to the research article entitled "Application of climate-based daylight simulation to assess lighting conditions of space and artworks in historical buildings: the case study of Cetacean Gallery of the Monumental Charterhouse of Calci", published on the Journal of Cultural Heritage [5]. (C) 2020 The Author(s). Published by Elsevier Inc.Article Citation - WoS: 56Citation - Scopus: 63Processing, Characterization and Photocatalytic Properties of Cu Doped Tio2 Thin Films on Glass Substrate by Sol-Gel Technique(Elsevier Ltd., 2006) Çelik, Erdal; Gökçen, Z.; Azem, N. Funda Ak; Tanoğlu, Metin; Emrullahoğlu, O. F.The present paper describes processing, properties and photocatalytic application of Cu doped TiO2 thin films on glass substrate. Cu doped TiO2 coatings were successfully prepared on glass slide substrates using sol-gel method. The obtained solutions exhibit acidic characteristics. The phase structure, thermal, microstructure and surface properties of the coatings were characterized by using XRD, DTA/TG, SEM and AFM. Their adhesion properties and spectroscopic analysis were investigated by a scratch tester and UV-vis spectroscopy. Four different solutions were prepared by changing Cu/Ti ratios. Glass substrates were coated by solutions of Ti-alkoxide, Cu-chloride, glacial acetic acid and isopropanol. The obtained gel films were dried at 300 degrees C for 10 min and subsequently heat-treated at 500 degrees C for 5 min in air. The oxide thin films were annealed at 600 degrees C for 60min in air. TiO2, CuO, Cu4Ti, Ti3O5 and Cu3TiO4 phases were found in the coating. The organic matters were burned at temperatures between 200 and 350 degrees C and TiO2 crystallization was formed at 450 degrees C. The weight loss of the powder during process up to 600 degrees C is approximately 70%. The microstructural observations demonstrated that CuO content was led an improved surface morphology while thickness of the film and surface defects were increased in accordance with number of dipping. According to AFM results, it was found that as the Cu/Ti content increases the surface roughness of the films increases. In addition structural, thermal and microstructural results, it was found that the films of 0.73 ratio have better adhesion strength to the glass substrate among other coatings. The oxide films were found to be active for photocatalytic decomposition of metylene blue. (c) 2006 Published by Elsevier B.V.Article Citation - WoS: 7Citation - Scopus: 8Investigation of the Structural and Optical Properties of Copper-Titanium Oxide Thin Films Produced by Changing the Amount of Copper(Elsevier Ltd., 2019) Horzum, Şeyda; Gürakar, Sibel; Serin, TülayWe examine how the structural, morphological and optical properties of TiO2 thin films are changed with heavily copper (Cu) content. Variations in characteristic properties of the films with 0, 12.5, 25 and 50 wt% Cu contents, grown by sol-gel dip coating method, are observed by using X-ray diffraction (XRD), Raman scattering, atomic force microscopy, energy dispersive X-ray analysis and optical spectroscopy measurements. The XRD and Raman spectra indicate that pure TiO2 film forms in the anatase structure. At high Cu concentrations, XRD results also reveal the substitution of Ti with Cu and formation of extra compound Copper-Titanium oxide. Raman measurements also show that Cu is incorporated homogeneously into TiO2 matrix up to 12.5 wt% concentration and this uniformity is distorted at higher Cu contents. In addition, optical spectroscopy measurements show that the optical band gap energy decreases from 3.26 eV to 2.05 eV with increasing Cu concentration. Furthermore, it is observed that the refractive index values obtained by means of transmittance spectra at 550 nm wavelength; increases from 2.47 to 3.39 when the Cu concentration increases from 0 to 50 wt %.Article Citation - WoS: 30Citation - Scopus: 32Perylene-Embedded Electrospun Ps Fibers for White Light Generation(Elsevier Ltd., 2019) Güner, Tuğrul; Aksoy, Erkan; Demir, Mustafa Muammer; Varlıklı, CananPerylene dyes have been employed in the fabrication of white light due to their superior photophysical properties and relatively easy synthetic methods. However, their molecular aggregation in solid state is one of the main handicaps since it causes deviation in their optical properties and quenches photoluminescence quantum yields (Phi(f)). Investigation of the photophysical properties of a green (PTE), a yellow (PDI) and a new red (DiPhAPDI) emitting perylene derivative in solution, drop-casted films, polystyrene (PS) fibers and PS fibers embedded in poly (dimethyl siloxane) (PDMS) showed that PS:dye fibers prevent aggregation to some extend and allows high Of of dyes. The Of values of PTE, PDI and DiPhAPDI were all higher than 93.0% in solution and 84.8%, 94.3% and 73.6%, respectively in PS:dye fibers. Embedding the fibers in PDMS improved the photostabilities of the dyes two folds compared to their solution phases. The prepared dye containing fibers were combined together into a single PDMS film and utilized as a frequency conversion layer on a blue LED. Fabricated samples were found to show high color rendering index (>= 90), adjustable CCT (7500 K-5000 K), and power efficiency values exceeding 2001m/W depending on the used fiber amount in mass.