Download or read book Dissolution of Borate Glasses and Precipitation of Phosphate Compounds written by Jaime Lynn George and published by . This book was released on 2015 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Borate glasses have been developed for biomedical applications such as scaffolds for soft tissue and bone repair. The dissolution processes of borate glasses in phosphate-containing aqueous solutions were studied by [mu]-Raman spectroscopy which provided information about the types and concentrations of borate species released into the solution as a function of time and characterized the formation of calcium phosphate reaction products on the glass surface. Boric acid molecules (H3BO3) and borate anions (B(OH)4−) can be detected in solution and their relative concentrations depend on the solution pH. Static and dynamic single-pass flow-through experiments were employed to study the dissolution kinetics of a borate bioactive glass 13-93B3 in water, simulated body fluid (SBF), and other solutions. As the glasses react, B-, Ca-, Na-, K-, Mg-, and P-species were released from the glass and a magnesium-containing amorphous calcium phosphate (ACP) or hydroxyapatite (HAP) layer formed on the surface of the glass. The formation of crystalline hydroxyapatite was favored with faster flow rates, longer reaction times, and increased phosphate concentration in solution. Under static conditions, the dissolution rates are initially described by a reaction-controlled model (linear kinetics), but after the glass is ~25-30% reacted, a diffusion-controlled model (parabolic kinetics) better describes the dissolution rates. The change in reaction mechanism is attributed to the diffusion of species from the glass through the ACP layer. The activation energy for the reaction-controlled process is 41.1±0.6 kJ/mol, whereas the activation energy for the diffusion process is 32.3±0.1 kJ/mol. For the SPFT experiments, glasses dissolved faster under faster flow rates and smaller glass volumes. The ion release rate was calculated and found to range from 1.7x10−5 g/m2/s for slow flow rates to 1.1x10−3 g/m2/s for lower glass volumes."--Abstract, page iv.
Download or read book WASTES Solutions Treatments and Opportunities II written by Candida Vilarinho and published by CRC Press. This book was released on 2017-09-01 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wastes: Solutions, Treatments and Opportunities II contains selected papers presented at the 4th edition of the International Conference Wastes: Solutions, Treatments and Opportunities, that took place 25-26 September 2017 at the Faculty of Engineering of the University of Porto, Porto, Portugal. The Wastes conference, which takes place biennially, is a prime forum for academics and industry representatives from the waste management and recycling sectors around the world to share their experience and knowledge with all in attendance. The published papers focus on a wide range of topics, including: Wastes as construction materials, Wastes as fuels, Waste treatment technologies,MSW management, Recycling of wastes and materials recovery, Wastes from new materials (nanomaterials, electronics, composites, etc.), Environmental, economic and social aspects in waste management and Circular economy.
Download or read book Biomedical Therapeutic and Clinical Applications of Bioactive Glasses written by Gurbinder Kaur and published by Woodhead Publishing. This book was released on 2018-09-22 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomedical, Therapeutic and Clinical Applications of Bioactive Glasses is an essential guide to bioactive glasses, offering an overview of all aspects of the development and utilization of this cutting-edge material. The book covers vital issues, including mesoporosity, encapsulation technologies, scaffold formation and coatings for a number of applications, including drug delivery, encapsulation, scaffolds and coatings. Readers will gain a strong understanding and practical knowledge of the therapeutic aspects of bioceramics, with a focus on glasses from a clinical point-of- view. Researchers, students and scientists involved in bioceramics, bone tissue engineering, regeneration and biomedical engineering will find this to be a comprehensive resource. - Presents detailed coverage of bioactive glasses, including technologies and applications - Includes all the major development areas related to bioactive glasses, enabling readers to understand the latest research - Considers the potential future developments of bioactive glasses as a drug carrier
Download or read book Borate Glasses written by L. D. Pye and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boron Oxide plays a key role in numerous glasses of high technological importance, yet its role in glass structure is far from clear. Indeed, in recent years there have been serious chal lenges to previous structure concepts for both crystalline and glassy borates. These challenges were sufficient to warrant a re examination of the structure of borate glasses using the most pow erful tools currently available. To provide a suitable forum for this undertaking, a four-day conference on "Boron in Glass and Glass Ceramics" was convened at Alfred University, June 3-8, 1977 to review the best scientific thinking on structure and to debate conflicting views and discuss properties and applications of borate glasses. This conference was also the first in a New University series on Glass Science to be rotated among Alfred University, The Pensyl vania State University, Rensselaer Polytechnic Institute, and the University of Missouri-Rolla. The present volume represents the proceedings of the first conference in this series. The volume begins with a review of the remarkable contribution of Jan Krogh-Moe to the understanding of the structure of Borate glasses. This review, authored by Professor N. J. Kreidl, concludes by dedicating the proceedings of this conference as a Krogh-Moe Fest schrift. The volume continues with a historical review by D. L. Griscom, originally prepared for circulation to the contributors prior to the conference. An Epilogue to the opening chapter brings the survey up-to-date in light of the conference papers.
Download or read book Borate Glasses Crystals and Melts written by Alex C. Hannon and published by . This book was released on 2016 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the Eighth International Conference on Borate Glasses, Crystals, & Melts and First International Conference on Phosphate Materials held at University of Pardubice, Czech Republic on 30 June to 4 July 2014
Download or read book Dissolution Behavior of Alkali Borate Glasses written by Jessica Dawn Lowry and published by . This book was released on 2002 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Composition on the Viscosity Crystallization and Dissolution of Simple Borate Glasses and Compositional Design of Borate Based Bioactive Glasses written by Kathryn Lynn Goetschius and published by . This book was released on 2014 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Borate glasses have recently been developed for a variety of medical applications, but much less is known about their structures and properties than more common silicate glasses. Melt properties and crystallization tendency for compositions in the Na2O-CaO-B2O3 system were characterized using differential thermal analysis and viscosity measurements. Characteristic viscosity (isokom) temperatures varied with the ratio between the modifier content (Na2O+CaO) and B2O3, particularly at lower temperatures, consistent with the changes in the relative concentrations of tetrahedral borons in the glass structure. Similar glasses were used to study dissolution processes in water. These alkali-alkaline earth glasses dissolve congruently and follow linear dissolution kinetics. The dissolution rates were dependent on the glass structure, with slower rates associated with greater fractions of four-coordinated boron. For glasses with a fixed alkaline earth identity, the dissolution rates increased in the order Li
Download or read book Borate Glasses Crystals Melts written by Yanko B. Dimitriev and published by . This book was released on 2001 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Osteochondral Tissue Engineering written by J. Miguel Oliveira and published by Springer. This book was released on 2018-04-24 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the most recent developments in the field of osteochondral tissue engineering (OCTE) and presents challenges and strategies being developed that face not only bone and cartilage regeneration, but also establish osteochondral interface formation in order to translate it into a clinical setting. Topics include nanotechnology approaches and biomaterials advances in osteochondral engineering, advanced processing methodology, as well as scaffolding and surface engineering strategies in OCTE. Hydrogel systems for osteochondral applications are also detailed thoroughly. Osteochondral Tissue Engineering: Nanotechnology, Scaffolding-Related Developments and Translation is an ideal book for biomedical engineering students and a wide range of established researchers and professionals working in the orthopedic field.
Download or read book The Dissolution of Soluble Phosphate Glasses written by Michael Charles Lloyd and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Sulfur on Structure and Conversion of Bioactive Borate Glasses written by Ali Mohammadkhah and published by . This book was released on 2012 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The effect of sulfur on glass structure and the conversion process of bioactive CaO-LI2O-B2O3 glasses were studied. One glass without and two glasses with different amounts of sulfur were made using conventional melting and dry quenching techniques. These glasses reacted with a phosphate solution and converted to hydroxyapatite. Particles (150-355[mu]m) were reacted in 0.25 and 0.5 molar K2HPO4 solutions at 37°C for 2 to 96 hours. The weight loss of the particles and the final pH of the solution were measured. The weight loss measurements indicated that the reaction rate increases with increasing the sulfur content. Sulfur was released from the glass, causing the pH of the solution to decrease, but was absent in the reacted layer. In the in-vivo studies, the effect of sulfur and phosphorus on the conversion of two different bioactive borate glasses was studied, in-vivo. Discs made from two sulfur-free glasses (CaLB-0 and 93B3-0) and two sulfur-containing glasses (CaLB-12 and 93B3-6) were implanted in a subcutaneous site in rats for 2, 4, and 12 weeks. Each rat remained healthy during the experiment and there were no sign of infection or necrosis at the implantation site. The CaLB glass discs reacted with the body fluids and formed a thin calcium phosphate reacted layer on their surface, but the 93B3 glass discs reacted to form a thicker calcium phosphate reacted layer with an onion-skin structure. Compared the phosphorus-free CaLB implants to phosphorus-containing 93B3 implants the CaLB implants absorbed 2 times more phosphorus from the body fluids to form the calcium phosphate reacted layer. Compared to the CaLB implants, the connective tissue attached to the 93B3 implants was ~3 times thicker, and contained more blood vessels and collagen. For all of the sulfur-containing implants sulfur released to the body fluids and was not presented in the reacted materials"--Abstract, leaf iv.
Download or read book Structure dissolution Relationships of Phosphate and Bioactive Glasses by Liquid Solid state and Paramagnetic NMR written by Dahiana Andrea Avila Salazar and published by . This book was released on 2022* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The doctoral thesis comprises a study of the relationships between structure and dissolution behaviour of phosphate and bioactive glasses by employing analytical techniques such as electron paramagnetic resonance (EPR), liquid NMR, solid-state MAS NMR and paramagnetic NMR spectroscopy, among others. The understanding of the corrosion processes of phosphate glasses is important for their technological applications, e.g. drug delivery, antibacterials and tissue engineering. In the present work, the NMR findings provided insights about the role of cations on the mechanism of hydrolysis of phosphate glasses. The incorporation of cobalt into glasses is a new approach to overcome the vascularization limitation in tissue engineering by stimulating the production of blood vessels. These glasses are also interesting as semiconductors, optical devices and solid-state lasers, among others. This work shows that structural (i.e. thermal) properties of cobalt phosphate glasses with constant basicity are dictated by the coordination number of Co2+ sites. The second part of the study on cobalt phosphate glasses is in publication process under the title: "Co2+ as an internal paramagnetic 31P NMR probe for structural analysis of cobalt-phosphate glasses in the solid-state and leachate solutions". This work presents a new approach to investigate the mechanism of dissolution of phosphate glasses based on the paramagnetic effects. Accordingly, features such as the spin-orbit (SO) coupling, zero-field splitting (ZFS) and symmetry of Co2+ sites are correlated to the paramagnetic shift, paramagnetic relaxation enhancement (PRE) and broadening effects on the spectra. That allows the assessment of the distribution of Co2+ ions in the glass network. Additionally, it enables monitoring structural dynamics of phosphate complexes in solution, including conformational changes, upon ligand binding recognition under different conditions, i.e. buffer aqueous solutions (Tris, EDTA).
Download or read book Interactions Between Water and Phosphate Glasses written by Brad Conrad Tischendorf and published by . This book was released on 2005 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The reactions between phosphate glasses and water have been characterized in a number of different environments. The weathering and aqueous dissolution properties of these glasses are presented under a range of temperature, humidity, and pH conditions. During the dissolution process, water is first absorbed by the glass surface and hydrated the surface disassociated the phosphate network and modifying cations. Once disassociated, the cations and chains are removed congruently from the glass surface. During these experiments it has been found that the addition of high field strength modifiers or the change in glass structure from the meta toward the pyrophosphate composition may be unable to improve the durability of the glass systems on their own. The weathering reactions of phosphate occur in a similar manner, with water initially absorbed by the glass surface and hydrating the modifiers and the phosphate network, isolating them from each other. It then continues with hydrolysis of the phosphate chains on the glass surface, and the production of a visible reaction layer, and can eventually lead to the precipitation of crystalline orthophosphate species on the glass surface. Modifying cations such as Al3 that can form bonds with lower ionic character can help to prevent water from hydrating the glass network. The phosphate network itself can also become more resistant to hydration as shorter phosphate chains appear to form stronger P-O-M bonds and also may electrostatically repel water. These high field strength modifiers will, however, accelerate the hydrolysis process once the surface is hydrated"--Abstract, leaf iv.
Download or read book Electrochemistry of Systems Containing Aluminum Phosphate Dissolved in Fused Borate and Phosphate Mixtures written by Tsei-Yu Chao and published by . This book was released on 1952 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bioactive Behavior of a Borate Glass written by Marina N. Richard and published by . This book was released on 2000 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: "For the past 30 years, the bioactive characteristics of special glass compositions have been demonstrated. Until now, phosphate containing soda-lime-silicate glasses such a 45S5 Bioglass®, were used to stimulate bone repair. Through the formation of an osteoconductive layer of hydroxyapatite (the main inorganic compound of bone) on the glass surface, direct bonding with bone will then occur. The rate of formation of hydroxyapatite was studied for the first silica-free borate glass of composition analogue to 45S5 and for a partially crystallized 45S5 glass. An cell-free process has been modeled to assess the formation of hydroxyapatite on the glass. The process involves the reaction of borate glass particles in phosphate solution of various molarity and starting pH. The formation of hydroxyapatite was observed best in a 0.1 Molar phosphate solution for both glasses. The reaction products have been investigated using X-ray diffraction (XRD), Infrared (IR) spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) and Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP). The positive outcome of the model lead to further investigation of the borate glass. In vitro experiments were performed using MC3T3-E1 bone cells. The borate glass provided a marginally suitable environment for the growth of cells due to the release of boron. Successful in vivo experiments demonstrated bone growth around the borate glass particles very similar to that for the commercially used 45S5 glass. The successful bioactive response obtained with the first silica-free glass composition opens the way to the development of other compositions for bioactive use. Based on our study, future medical applications of a bioactive borate glass may dramatically reduce the rehabilitation time for patients"--Abstract, leaf iv.
Download or read book Borate Glasses written by Lenwood D. Pye and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Borate Glasses written by L. D. Pye and published by Springer. This book was released on 1978-10-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boron Oxide plays a key role in numerous glasses of high technological importance, yet its role in glass structure is far from clear. Indeed, in recent years there have been serious chal lenges to previous structure concepts for both crystalline and glassy borates. These challenges were sufficient to warrant a re examination of the structure of borate glasses using the most pow erful tools currently available. To provide a suitable forum for this undertaking, a four-day conference on "Boron in Glass and Glass Ceramics" was convened at Alfred University, June 3-8, 1977 to review the best scientific thinking on structure and to debate conflicting views and discuss properties and applications of borate glasses. This conference was also the first in a New University series on Glass Science to be rotated among Alfred University, The Pensyl vania State University, Rensselaer Polytechnic Institute, and the University of Missouri-Rolla. The present volume represents the proceedings of the first conference in this series. The volume begins with a review of the remarkable contribution of Jan Krogh-Moe to the understanding of the structure of Borate glasses. This review, authored by Professor N. J. Kreidl, concludes by dedicating the proceedings of this conference as a Krogh-Moe Fest schrift. The volume continues with a historical review by D. L. Griscom, originally prepared for circulation to the contributors prior to the conference. An Epilogue to the opening chapter brings the survey up-to-date in light of the conference papers.
