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    Bioactive Sheath/Core Nanofibers Containing Olive Leaf Extract
    (Wiley-Blackwell, 2016) Dogan, Gamze; Basal, Guldemet; Bayraktar, Oguz; Ozyildiz, Figen; Uzel, Atac; Erdogan, Ipek
    This study aimed at producing silk fibroin (SF)/hyaluronic acid (HA) and olive leaf extract (OLE) nanofibers with sheath/core morphology by coaxial electrospinning method, determining their antimicrobial properties, and examining release profiles of OLE from these coaxial nanofibers. Optimum electrospinning process and solution parameters were determined to obtain uniform and bead-free coaxial nanofibers. Scanning electron microscopy and transmission electron microscopy (TEM) were used to characterize the morphology of the nanofibers. The antimicrobial activities of nanofibers were tested according to AATCC test method 100. Total phenolic content and total antioxidant activity were tested using in vitro batch release system. The quality and quantity of released components of OLE were determined by high-performance liquid chromatography. The changes in nanofibers were examined by Fourier-transform infrared spectroscopy. Uniform and bead-free nanofibers were produced successfully. TEM images confirmed the coaxial structure. OLE-loaded nanofibers demonstrated almost perfect antibacterial activities against both of gram-negative and gram-positive bacteria. Antifungal activity against C. albicans was rather poor. After a release period of 1 month, it was observed that similar to 70-95% of the OLE was released from nanofibers and it was still bioactive. Overall results indicate that the resultant shell/core nanofibers have a great potential to be used as biomaterials. (C) 2015 Wiley Periodicals, Inc.
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    Comfort properties of double layered knitted and woven fabrics
    (Inst Natl Cercetare-Dezvoltare Textile Pielarie-Bucuresti, 2009) Basal, Guldemet; Mecit, Diren; Duran, Deniz; Ilgaz, Sevcan
    Comfort properties of double layered knitted and woven fabrics The study provides comprehensive and informative data on the comfort related material properties of double layered knitted and woven fabrics, produced from engineered polyester, cotton and viscose yams, designed as cover sheets. The knitted fabrics were produced at two different course densities with the top layer consisted of either four channeled polyester (ChPES) yarn or a micro-blend of polyester and cotton (MbPES/CO) yarn, and the bottom layer consisted of either cotton or viscose yam. Woven fabrics were produced at three weft densities with either ChPES or MbPES/CO warp and top weft, and cotton or viscose bottom weft. In order to evaluate and compare the properties of these fabrics, different trials were achieved regarding the wearability comfort of clothing made of these materials. Results showed that ChPES yarns provided better water absorbency and wicking ability, lower thermal conductivity and air permeability, and higher friction. MbPES/CO yarns ion the other hand, presented higher air permeability, lower friction, higher thermal conductivity and lower water absorption and wicking. Whig cotton yams improved the water absorption and wicking, viscose yarns resulted in higher air permeability in knitted fabrics. In addition, at high course and weft densities water absorption, water wicking and heat transfer were high, and air permeability was low.
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    Comparison of properties and structures of compact and conventional spun yarns
    (Sage Publications Ltd, 2006) Basal, Guldemet; Oxenham, William
    The properties and structural parameters of compact and conventional ring yarns produced at five different twist levels were compared. A modified version of the tracer fiber technique (J. Textile Inst., 43, T60-T66, 1952) combined with the Image Analysis Application Version 3.0 (B.A.R.N. Engineering) was utilized to explore yarn structure. Results obtained from these analyses showed that the high tenacity values of compact yams can be attributed to the higher rate and amplitude of fiber migration in these yarns compared to those in conventional ring yarns. Another important finding was the superiority of compact yarns in terms of tensile properties is less noticeable at higher twist levels and in 50/50 polyester/cotton blend.
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    The effects of crosslinker ratio and photoinitiator type on the properties of pnipam hydrogel
    (Springer, 2023) Oral, Nur; Basal, Guldemet
    In this study, Poly(N-isopropylacrylamide) (PNIPAM) hydrogels were produced from N-isopropylacrylamide (NIPAM), at three different concentrations of crosslinker, N,N & PRIME;-methylenebisacrylamide (BIS) (0.50%, 0.35%, and 0.25%) using two types of photoinitiator, a hydrophilic photoinitiator (Irgacure 2959) and a hydrophobic photoinitiator (Irgacure 651). When Irgacure 651 was used photopolymerization process was completed in 20 min compared to two hours with Irgacure 2959. However, the resultant hydrogels were opaque suggesting a heterogeneous structure, which in turn led to low compressive strength. Besides, when hydrogel solution was prepared with Irgacure 651 in water/ethanol mixture 0.25% crosslinker ratio was not sufficient to form a hydrogel. Irgacure 2959 produced homogenous transparent hydrogels with a higher degree of swelling. When the crosslinker ratio decreased swelling capacity increased, but hydrogels became weaker. The decrease in compressive strength was particularly high at the 0.25% crosslinker ratio. The crosslinker ratio or photoinitiator type did not have any significant effect on the phase transition temperature. On the other hand, hydrogel samples prepared with Irgacure 651 in water/ethanol mixture showed a quicker response to swelling and deswelling. In conclusion, in terms of morphology, swelling capacity, and compressive strength the best results were obtained with the crosslinker ratio of 0.35% and Irgacure 2959.
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    Effects of some process parameters on the structure and properties of vortex spun yarn
    (Sage Publications Ltd, 2006) Basal, Guldemet; Oxenham, Wiliam
    The effects of a number of process parameters, including the nozzle angle, nozzle pressure, spindle diameter, yarn delivery speed, and distance between the front roller and the spindle, on the structure and properties of vortex spun yarns were investigated. A modified version of the tracer fiber technique (J. Text. Inst., 43, T60-T66, 1952) combined with the Image Analysis Application Version 3.0 (B.A.R.N. Engineering) was utilized to explore yarn structure. The migration behavior of fibers was characterized using the migration parameters introduced by Hearle et al. (Text. Res. J., 35, 329-334,788-795, 1965). The results showed that the short front roller to the spindle distance caused better evenness, low imperfections, and less hairiness. High nozzle angle, high nozzle pressure, low yarn delivery speed and small spindle diameter reduced hairiness as well. High nozzle angle, high nozzle pressure and low speed also led to higher fiber migration. Surprisingly nozzle angle, nozzle pressure or delivery speed did not have any significant effects on yarn tensile properties. This is believed to be caused by the relatively small differences between the levels of these parameters used in the trials. The present study provides a window into the vortex spinning technology, but further research needs to be conducted to establish a "process-structure-property model" for vortex yarns.
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    ELASTIC BANDAGES WITH IMPROVED COMFORT PROPERTIES
    (Ege Universitesi, 2016) Basal, Guldemet; Deveci, Senem Sirin
    Elastic bandage samples were produced on a crochet knitting machine utilizing some special polyester, cotton and viscose yarns. Air permeability, porosity, thermal conductivity, thermal absorbtivity, thermal resistance and water absorbency of these bandages were compared. Results revealed that air permeability depended on fabric density and porosity. Capillarity action played a significant role in water absorbency. Particularly, channeled fiber structure improved water absorbency in a great extent. Thermal conductivity was affected by fiber type and fabric density. Cotton and viscose fibers, and dense fabric structure caused high thermal conductivity. Thermal resistance showed an opposite trend. In addition, in order to improve thermal comfort characteristics of the bandages phase change material (PCM) loaded microcapsules were applied to one of bandage samples. Alambeta test results confirmed that application of PCM microcapsules improved the thermal comfort properties of bandages in some extend.
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    A Functional Fabric for Pressure Ulcer Prevention
    (Sage Publications Ltd, 2009) Basal, Guldemet; Ilgaz, Sevcan
    Pressure ulcers, also known as bed sores, pressure sores and decubitus ulcers, are localized areas of tissue damage that develop due to pressure usually over a bony prominence. They are associated with adverse health outcomes and high treatment costs. This study focused on developing a functional fabric for pressure ulcer prevention. For this purpose, face-to-face velour weaving technique was utilized to produce a spacer fabric from the different combinations of engineered polyester, polypropylene, cotton and viscose fibers. Thermal conductivity, thermal resistance, thermal absorptivity, water vapor permeability, wicking ability, compressibility and fabric hand properties of the resultant 32 fabrics were examined. Based on the results, channeled polyester, cotton and polypropylene were determined as the most promising fiber types for the final product.
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    A Functional Fabric for Pressure Ulcer Prevention
    (Sage Publications Ltd, 2009) Basal, Guldemet; Ilgaz, Sevcan
    Pressure ulcers, also known as bed sores, pressure sores and decubitus ulcers, are localized areas of tissue damage that develop due to pressure usually over a bony prominence. They are associated with adverse health outcomes and high treatment costs. This study focused on developing a functional fabric for pressure ulcer prevention. For this purpose, face-to-face velour weaving technique was utilized to produce a spacer fabric from the different combinations of engineered polyester, polypropylene, cotton and viscose fibers. Thermal conductivity, thermal resistance, thermal absorptivity, water vapor permeability, wicking ability, compressibility and fabric hand properties of the resultant 32 fabrics were examined. Based on the results, channeled polyester, cotton and polypropylene were determined as the most promising fiber types for the final product.
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    A Hydrophilic/Hydrophobic Composite Structure for Water Harvesting from the Air
    (E.U. Printing And Publishing House, 2022) Basal, Guldemet; Oral, Nur
    The freshwater shortage is one of the world's most pressing challenges needs to be addressed rapidly. To overcome this challenge, harvesting water from the air has emerged as a simple and cost-effective approach. Traditional wire meshes have been already used for atmospheric water harvesting from the fog. In foggy areas, the wire meshes are placed perpendicular to wind and water droplets in fog carried by the wind are trapped and deposited on the surface of meshes. The purpose of this study is to improve the water harvesting capacity of the traditional wire mesh by modifying its surface using a nature-inspired composite structure consisting of hydrophilic and hydrophobic zones. Hydrophilic zones were obtained by electrospinning or electrospraying of the polyamide 6 (PA6) / chitosan (CH) blend, and hydrophobic zones were attained by electrospraying of polycaprolactone (PCL). The water harvesting capacity of the resulting meshes was tested and compared with each other. The highest water harvesting capacity was achieved with the PA6/CH nanofiber coated wire mesh as 87 mg / cm2/h. This mesh collected twice as much water compared to the uncoated mesh. However, its water collection rate decreased when nanofiber surface reached the saturation level. The addition of hydrophobic PCL particles onto PA6/CH nanofibers significantly reduced the amount of water captured. When both PA6/CH and PCL were electrosprayed on the wire mesh in particle form water harvesting capacity slightly increased, but it was still poor compared to uncoated mesh.
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    Innovative 3D-printed surfaces for efficient water harvesting from air
    (Emerald Group Publishing Ltd, 2024) Koyun, Furkan Turan; Sabur, Sema; Basal, Guldemet; Gunerhan, Huseyin
    PurposeThe purpose of this study is to develop nature-inspired 3D surfaces for atmospheric water harvesting.Design/methodology/approachInitially, cylindrical-shaped protrusions were produced utilizing a 3D printer to obtain a surface with a high surface area. Subsequently, an electrospraying technique was employed to coat the tips of these hydrophobic protrusions with hydrophilic nano-scale particles and fibers, utilizing polyamide 6 (PA6) or PA6/chitosan (CH) blends. In the next stage of the study, the impact of protrusion shape was investigated by fabricating surfaces with cylindrical, conical and tree-shaped protrusions. Following the production of 3D surfaces, PA6 was electrosprayed onto the protrusions to achieve varied wettability patterns on the 3D surface. Finally, the water collection rates and capacities of the surfaces were evaluated.FindingsWater collection tests demonstrated that PA6-coated surfaces exhibited greater water collection capacity compared to untreated surfaces. Furthermore, the addition of CH enhanced the water collecting efficiency of the 3D surface. It was found that the shape of the protrusions significantly influenced water collection capacity. Particularly, cone-shaped protrusions exhibited the highest water collecting capability among the different shapes tested.Originality/valueIn this study, 3D printing and electrospraying techniques were combined to create 3D surfaces characterized by high surface area, along with hydrophilic and hydrophobic regions to produce superior surfaces for atmospheric water harvesting.
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    Polyamide 6/chitosan nanofiber coated HEPA filter for bioaerosol control
    (Inst Natl Cercetare-Dezvoltare Textile Pielarie-Bucuresti, 2017) Ozden, Deniz; Basal, Guldemet
    The aim of this study was to electrospun uniform nanofibers with antibacterial properties, to combine them with a high-efficiency particulate air (HEPA) filter material and to determine the filter performance of this composite filter. To achieve these objectives, polyamide 6 (PA 6)/chitosan (CS) blend nanofibers were produced and their antibacterial activity was analyzed. Then PA 6/CS nanofibers were coated on a commercial HEPA filter material and the filter performance of this composite filter was tested. Antibacterial activity analysis indicated that PA 6/CS nanofibers had very good antibacterial activity against both Staphylococcus aureus and Escherichia coli. Nanofiber coating improved the filter efficiency of the HEPA filter. However, it also increased pressure drop. The filter efficiency increased with decreasing nanofiber size in nanofiber coated HEPA filter. Pressure drop did not follow the same trend. First, it decreased with decreasing fiber diameter, but a further decrease in fiber diameter caused an increase in pressure drop. In conclusion, nanofiber size has a great effect on pressure drop and to get high filter efficiency without a substantial increase in pressure drop a careful selection of nanofiber size is essential.
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    Preparation of PCM microcapsules by complex coacervation of silk fibroin and chitosan
    (Springer, 2009) Deveci, Senem Sirin; Basal, Guldemet
    Phase change material microcapsules were prepared by complex coacervation of silk fibroin (SF) and chitosan (CHI). n-Eicosane was used as the core material. The effects of SF/CHI ratio, and percentage of cross-linking agent and n-Eicosane content on the properties of microcapsules were studied. The size distribution and the surface morphology of microcapsules were characterized by optical and scanning electron microscopy. The encapsulation of core material was determined by energy dispersive spectrometer analysis. The results indicated that SF/CHI microcapsules were prepared successfully. Microcapsules had smooth outer surface when the ratio of SF to CHI was close to 5. On the other hand, at high SF/CHI ratios (a parts per thousand yen14), microcapsules showed a two-layer structure, an inner compact layer, and an outer, more porous, sponge-like layer. The highest microencapsulation efficiency was obtained at a SF/CHI ratio of 20 in the presence of 0.9% cross-linking agent and of 1.5% n-Eicosane content.
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    Preparation of PCM microcapsules by complex coacervation of silk fibroin and chitosan
    (Springer, 2009) Deveci, Senem Sirin; Basal, Guldemet
    Phase change material microcapsules were prepared by complex coacervation of silk fibroin (SF) and chitosan (CHI). n-Eicosane was used as the core material. The effects of SF/CHI ratio, and percentage of cross-linking agent and n-Eicosane content on the properties of microcapsules were studied. The size distribution and the surface morphology of microcapsules were characterized by optical and scanning electron microscopy. The encapsulation of core material was determined by energy dispersive spectrometer analysis. The results indicated that SF/CHI microcapsules were prepared successfully. Microcapsules had smooth outer surface when the ratio of SF to CHI was close to 5. On the other hand, at high SF/CHI ratios (a parts per thousand yen14), microcapsules showed a two-layer structure, an inner compact layer, and an outer, more porous, sponge-like layer. The highest microencapsulation efficiency was obtained at a SF/CHI ratio of 20 in the presence of 0.9% cross-linking agent and of 1.5% n-Eicosane content.
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    Production of Novel Textile-Based Artificial Anterior Cruciate Ligament
    (Univ Ljubljani, Fac Natural Sci & Engineering, Dept Textiles, 2016) Aka, Cetin; Basal, Guldemet
    The aim of this research was to produce artificial anterior cruciate ligaments (ACL) using the weaving (plain and leno) and braiding techniques, and to compare the mechanical and fatigue life properties of these ligaments with the natural ACL. For this purpose, tubular fabric structures were produced on braiding and weaving machines from polyester and Vectran yarns. To turn these structures into ligaments, the core of the tubes were filled with straight yarns. The mechanical properties of the resulted ligaments were tested before and after a fatigue test. The results showed that all produced ligaments provide enough tensile strength and breaking elongation when they were compared with the natural ACL mechanical properties. After the fatigue test, the tensile strength of ligaments did not decline substantially. Regarding the tensile strength, the leno weaving structure has the most similar properties to the natural ACL. The leno weaving ligament made from Vectran has one-third of the strain percentage of the natural ACL.
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    Properties of n-Eicosane-Loaded Silk Fibroin-Chitosan Microcapsules
    (Wiley-Blackwell, 2011) Basal, Guldemet; Deveci, Senem Sirin; Yalcin, Dilek; Bayraktar, Oguz
    PCM microcapsules containing n-eicosane were prepared by complex coacervation of silk fibroin (SF) and chitosan (CHI). Chemical characterization of microcapsules was carried out using Fourier-transform infrared (FT-IR) spectroscopy. Thermal properties and thermal stability of microencapsulated n-eicosane were determined by differential scanning calorimetry (DSC) and thermal gravimetric analysis TGA). FTIR spectra confirmed the encapsulation of n-eicosane within the microcapsules. Results from thermal analyses showed that microcapsules consisted of an average of 45.7 wt % n-eicosane, and had a thermal energy storage and release capacity of about 93.04 J/g and 89.68 J/g, respectively. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121:1885-1889, 2011