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Neslihan Alemdar – 1st expert on this subject based on the ideXlab platform
Production of ciprofloxacin loaded chitosan/gelatin/Bone Ash wound dressing with improved mechanical propertiesCarbohydrate Polymers, 2019Co-Authors: Begüm Evranos, Didem Aycan, Neslihan AlemdarAbstract:
Abstract Polymeric films with enhanced mechanical performance were fabricated by incorporation of Bone Ash (BA) at various concentrations (0 to 25 v. %) into chitosan/gelatin (CTS/GEL) polymeric structure as a wound healing-dressing. The test results for mechanical performance of polymeric films proved that the encapsulation of BA into the polymeric films enhances the elastic modulus and tensile strength of polymeric films significantly. Oxygen permeability and water vapor transmission rate (WVTR) of films were also improved by BA reinforcement. Ciprofloxacin was chosen as the antibacterial model drug. The release of ciprofloxacin was provided in a more controlled manner at pH 7.4 owing to the incorporation of Bone Ash into the polymeric films. Also, drug loaded films showed great antibacterial activity against Escherichia coli and Bacillus subtilis bacteria. The results prove that ciprofloxacin loaded BA reinforced CTS/GEL composite films are potentially applicable in controlled drug delivery as wound dressings.
development of ph responsive chitosan based hydrogel modified with Bone Ash for controlled release of amoxicillinCarbohydrate Polymers, 2017Co-Authors: Didem Aycan, Neslihan AlemdarAbstract:
Abstract In present study, Bone Ash-reinforced chitosan-based hydrogels were obtained by encapsulation of Bone Ash into the hydrogel structure which was fabricated by photopolymerization of chitosan-grafted-glycidyl methacrylate (CTS-g-GMA) and poly(ethylene glycol)diacrylate (PEGDA) under the UV light. Hydrogels were characterized by ATR-FTIR, SEM and XRD analyses. Mechanical performance of the hydrogels was determined by universal mechanical tester. Cytotoxicity tests for hydrogels were conducted with L929 cell lines to determine cellular compatibility. Swelling tests were carried out to investigate the water uptake capacity of hydrogels. Amoxicillin which could be used for treatment of gastric ulcer was selected as the model drug. The release of amoxicillin was provided at simulated gastric (pH: 1.2) and intestinal media (pH: 7.4) in efficient and controlled manner. All results visualized that the obtained pH-sensitive chitosan-based hydrogel with enhanced mechanical properties could be a potential candidate as a drug carrier for treatment of gastric ulcer in the future applications.
fabrication of a novel Bone Ash reinforced gelatin alginate hyaluronic acid composite film for controlled drug deliveryCarbohydrate Polymers, 2016Co-Authors: Neslihan AlemdarAbstract:
Abstract In this study, a novel pH-sensitive composite film with enhanced thermal and mechanical properties was prepared by the incorporation of Bone Ash at varying concentrations from 0 to 10 v.% into gelatin/sodium alginate/hyaluronic acid (Gel/SA/HyA) polymeric structure for colon-specific drug delivery system. Films were characterized by FT-IR, SEM, and XRD analyses. Thermal and mechanical performances of films were determined by DSC, TGA and universal mechanical tester, respectively. Results proved that thermal stability and mechanical properties of Bone Ash-reinforced composite films improved significantly with respect to that of neat Gel/SA/HyA film. Cytotoxicity assay for composite films was carried out by using L929 cells. Water uptake capacity of films was determined by swelling test. Herein, release experiments of 5-Fluorouracil (5-FU) were performed in two different solutions (pH 2.1 and 7.4). The results assured that Gel/SA/HyA film containing BA could be considered as a potential biomaterial for controlled drug delivery systems.
T Altzitzoglou – 2nd expert on this subject based on the ideXlab platform
measurement of low level radioactivity in Bone AshJournal of Environmental Radioactivity, 1999Co-Authors: R Pilvio, J J Larosa, D Mouchel, R Wordel, M Bickel, T AltzitzoglouAbstract:
Abstract Bone is a critical organ for the accumulation of many radionuclides including 90 Sr and the actinides. The National Institute of Standards and Technology (0NIST) has prepared Bone Ash samples with a view to producing a standard reference material. The Institute for Reference Materials and Measurements (IRMM) participated in the analysis for the certification of the radionuclide concentrations in the Bone Ash. This article describes the assaying of the actinides, 90 Sr, 210 Pb and 226 Ra activity concentrations. A radiochemical procedure based on extraction chromatography has been developed to separate these radionuclides from the Bone Ash. The activity concentrations of the actinides, 210 Pb and 226 Ra have been measured using gamma-ray spectrometry and alpha-particle spectrometry and that of 90 Sr using low-level liquid scintillation counting.
Measurement of 90Sr in Bone Ash.Applied radiation and isotopes : including data instrumentation and methods for use in agriculture industry and medicine, 1998Co-Authors: T Altzitzoglou, J J Larosa, C NichollAbstract:
Bone is a critical organ for the accumulation of many radionuclides, including 90Sr. A Bone Ash has been prepared by NIST to become a standard reference material and the assaying of the 90Sr activity concentration is reported. A radiochemical procedure, based on extraction chromatography using a crown ether, has been developed to separate Sr from the Bone Ash. The natural Sr content of the Bone Ash has been determined by isotope dilution inductively coupled plasma mass spectrometry. The 90Sr activity concentration has been measured by low-level liquid scintillation counting.
Development of the NIST Bone Ash standard reference material for environmental radioactivity measurement.Applied radiation and isotopes : including data instrumentation and methods for use in agriculture industry and medicine, 1998Co-Authors: T Altzitzoglou, D Arnold, D Cavadore, M Korun, H Wershofen, Y Takata, A YoungAbstract:
The Bone Ash standard reference material (SRM), a blend of 4% contaminated human Bone and 96% diluent bovine Bone, has been developed for radiochemical method validation and quality control for radio-Bone analysis. The massic activities of 90Sr, 226Ra, 230Th, 232Th, 234U, 235U, 238U, 238Pu, (239 + 240)Pu and (243 + 244)Cm were certified using a variety of radiochemical procedures and detection methods. Measurements confirmed undetectable radionuclide heterogeneity down to a sample size of 5 g. thereby implying adequate blending of particulate materials with dilution factors of up to 17,900. The results among most of the intercomparison laboratories and their methods were consistent. Disequilibrium was observed for decay chains: 234U(0.67 mBq/g)-230Th(0.47 mBq/g)-226Ra(15.1 mBq/g)-210Pb(23 mBq/g)-210Po(13 mBq/g) and 232Th(0.99 mBq/g)-228 Ra(6.1 mBq/g)-228Th(7.1 mBq/g). The disequilibria were the results of mixing occupationally contaminated human Bone with natural bovine Bone and the fractionation during internal biological processes. The massic activity of 210Pb, 228Th and 241Am were not certified because of insufficient 228Ra and 241Pu data and lack of knowledge in how 222Rn and its daughters will be fractionated in the SRM bottle over time.
Douglas Gouvea – 3rd expert on this subject based on the ideXlab platform
using Bone Ash as an additive in porcelain sinteringCeramics International, 2015Co-Authors: Douglas Gouvea, Henrique Kahn, Taisa Tisse Kaneko, Edilene De Souza Conceicao, Juliana Livi AntoniassiAbstract:
Abstract Calcined bovine Bone (CBB) is generally used to manufacture high-quality porcelain known as Bone china. In these products, the amount of Bone Ash is about 50%. However, it is known that CBB, in small quantities added to raw materials such as feldspars, can reduce the liquidus temperature and thus promote liquid-phase sintering. The purpose of this study was to evaluate the potential use of Bone Ash as a sintering promoter of porcelain made by a classical triaxial system. Hard porcelain was prepared with 0, 1, 2, and 5 wt% CBB and sintered at temperatures ranging from 1100 to 1400 °C. For the sample containing 2% CBB, the sintering temperature was reduced by 50 °C relative to 0% CBB, while the sample’s tensile strength was the highest among all samples. Two mechanisms could be observed during porcelain sintering depending on CBB quantities: for 1 and 2% of CBB, the mullite formation determined the final shrinkage without changes on initial sintering temperatures; for 5% the initial sintering temperature was decreased by liquid formation.
surface modification of bovine Bone Ash prepared by milling and acid wAshing processCeramics International, 2009Co-Authors: Douglas Gouvea, Gerardo Augusto Vera Alatrista, S L M Brito, Ricardo H R Castro, Henrique KahnAbstract:
Abstract Bovine Bone Ash is the main raw material for fabrication of Bone china, a special kind of porcelain that has visual and mechanical advantages when compared to usual porcelains. The properties of Bone china are highly dependent on the characteristics of the Bone Ash. However, despite a relatively common product, the science behind formulations and accepted fabrication procedures for Bone china is not completely understood and deserves attention for future processing optimizations. In this paper, the influence of the preparation steps (firing, milling, and wAshing of the Bones) on the physicochemical properties of Bone Ash particles was investigated. Bone powders heat-treated at temperatures varying from 700 to 1000 °C were wAshed and milled. The obtained materials were analyzed in terms of particle size distribution, chemical composition, density, specific surface area, FTIR spectroscopy, dynamic electrophoretic mobility, crystalline phases and scanning electron microscopy. The results indicated that Bone Ash does not significantly change in terms of chemistry and physical features at calcination temperatures above 700 °C. After wAshing in special conditions, one could only observe hydroxyapatite in the diffraction pattern. By FTIR it was observed that carbonate seems to be mainly concentrated on the surface of the powders. Since this compound can influence in the dispersion stability, and consequently in the quality of the final Bone china product, and considering optimal wAshing parameters based on the dynamic electrophoretic mobility results, we describe a procedure for surface cleaning.
effect of calcination temperature on the properties of bovine Bone Ash for the fabrication of Bone chinaCerâmica, 2007Co-Authors: Douglas Gouvea, Gerardo Augusto Vera Alatrista, S Bernard, S M TofolliAbstract:
Calcined bovine Bones comprise the main raw material for the fabrication of Bone China (more than 50 wt.%). This special kind of porcelain has never been produced in Brazil. In this paper, the influence of the following preparation steps: firing, grinding, and wAshing of the Bones, on the physicochemical characteristics of the obtained Bone Ash particles was investigated. Powders calcined at temperatures between 700 and 1000 oC, wAshed and ground, were analyzed in terms of their particle size distribution, chemical composition (X-ray fluorescence), density (He picnometry), specific surface area (BET method), infrared spectroscopy (FTIR-DRIFT), and also in a scanning electron microscopy. The results indicated that Bones processed at different temperatures exhibit great homogeneity either in chemical terms (chemical composition and electrophoretic mobility) or in physical terms (particle size and phase composition), show slight increase in particle size with increasing firing temperatures and must be calcined under oxidizing atmospheres in order to develop good processing characteristics.