scholarly journals An overview of the effects of thermal processing on bioactive glasses

2010 ◽  
Vol 42 (3) ◽  
pp. 307-320 ◽  
Author(s):  
D. Bellucci ◽  
V. Cannillo ◽  
A. Sola
Keyword(s):  
Thermal Processing ◽  
Biomedical Applications ◽  
Soft Tissues ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Point Of View ◽  
Porous Scaffolds ◽  
Bioactive Glasses ◽  
Key Factor ◽  
Highly Porous

Bioglass? 45S5 is widely used in biomedical applications due to its ability to bond to bone and even to soft tissues. The sintering ability of Bioglass? powders is a key factor from a technological point of view, since its govern the production of advanced devices, ranging from highly porous scaffolds to functionalized coatings. Unfortunately this particular glass composition is prone to crystallize at the temperature required for sintering and this may impair the bioactivity of the original glass. For these reasons, a prerequisite to tailor the fabrication of Bioglass?-derived implants is to understand the interaction between sintering, crystallization and bioactivity. In this work the structural transformations which occur during the heat treatment of Bioglass? are reviewed and a special attention is paid to the sintering and crystallization processes. Moreover the bioactivity of the final glass-ceramics is discussed and some alternative glass formulations are reported.

scholarly journals Novel whey protein isolate-based highly porous scaffolds modified with therapeutic ion-releasing bioactive glasses

2020 ◽  
Vol 261 ◽  
pp. 127115 ◽  
Author(s):  
Michal Dziadek ◽  
Timothy E.L. Douglas ◽  
Kinga Dziadek ◽  
Barbara Zagrajczuk ◽  
Andrada Serafim ◽  
...  
Keyword(s):  
Whey Protein ◽  
Whey Protein Isolate ◽  
Protein Isolate ◽  
Porous Scaffolds ◽  
Bioactive Glasses ◽  
Highly Porous

scholarly journals Bioactive Glasses and Glass-Ceramics for Healthcare Applications in Bone Regeneration and Tissue Engineering

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2530 ◽  
Author(s):  
Hugo R. Fernandes ◽  
Anuraag Gaddam ◽  
Avito Rebelo ◽  
Daniela Brazete ◽  
George E. Stan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Soft Tissues ◽  
Glass Structure ◽  
Glass Ceramics ◽  
The Body ◽  
Healthcare Applications ◽  
Bioactive Glasses ◽  
Living Tissues ◽  
45S5 Bioglass

The discovery of bioactive glasses (BGs) in the late 1960s by Larry Hench et al. was driven by the need for implant materials with an ability to bond to living tissues, which were intended to replace inert metal and plastic implants that were not well tolerated by the body. Among a number of tested compositions, the one that later became designated by the well-known trademark of 45S5 Bioglass® excelled in its ability to bond to bone and soft tissues. Bonding to living tissues was mediated through the formation of an interfacial bone-like hydroxyapatite layer when the bioglass was put in contact with biological fluids in vivo. This feature represented a remarkable milestone, and has inspired many other investigations aiming at further exploring the in vitro and in vivo performances of this and other related BG compositions. This paradigmatic example of a target-oriented research is certainly one of the most valuable contributions that one can learn from Larry Hench. Such a goal-oriented approach needs to be continuously stimulated, aiming at finding out better performing materials to overcome the limitations of the existing ones, including the 45S5 Bioglass®. Its well-known that its main limitations include: (i) the high pH environment that is created by its high sodium content could turn it cytotoxic; (ii) and the poor sintering ability makes the fabrication of porous three-dimensional (3D) scaffolds difficult. All of these relevant features strongly depend on a number of interrelated factors that need to be well compromised. The selected chemical composition strongly determines the glass structure, the biocompatibility, the degradation rate, and the ease of processing (scaffolds fabrication and sintering). This manuscript presents a first general appraisal of the scientific output in the interrelated areas of bioactive glasses and glass-ceramics, scaffolds, implant coatings, and tissue engineering. Then, it gives an overview of the critical issues that need to be considered when developing bioactive glasses for healthcare applications. The aim is to provide knowledge-based tools towards guiding young researchers in the design of new bioactive glass compositions, taking into account the desired functional properties.

In Vitro Assessment of New Niobium Phosphate Glasses and Glass Ceramics

2007 ◽  
Vol 361-363 ◽  
pp. 229-232 ◽  
Author(s):  
Marcelo Henrique Prado da Silva ◽  
C. Moura Ramirez ◽  
José Mauro Granjeiro ◽  
Antonella M. Rossi
Keyword(s):  
Calcium Phosphate ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Phosphate Glasses ◽  
Biological Behavior ◽  
Bioactive Glasses ◽  
In Vitro Assessment ◽  
Niobium Phosphate

Niobo-phosphate glasses were produced in order to assess the citotoxicity of samples with different compositions. Different P2O5/Ca ratios were studied in an attempt to correlate the biological behavior of new niobo-phosphate bioactive glasses with conventional bioactive calcium phosphate glasses. The most biocompatible glass composition was chosen to produce glassreinforced hydroxyapatite composites.

Functional and Highly Porous Scaffolds for Biomedical Applications

2011 ◽  
Vol 11 (10) ◽  
pp. 1432-1442 ◽  
Author(s):  
Therese Tyson ◽  
Sofia Målberg ◽  
Veronica Wåtz ◽  
Anna Finne-Wistrand ◽  
Ann-Christine Albertsson
Keyword(s):  
Biomedical Applications ◽  
Porous Scaffolds ◽  
Highly Porous

Biological and biomedical applications of collagenous biomaterials

1990 ◽  
Vol 48 (3) ◽  
pp. 856-857
Author(s):  
Yasushi P. Kato ◽  
Michael G. Dunn ◽  
Frederick H. Silver ◽  
Arthur J. Wasserman
Keyword(s):  
Biomedical Applications ◽  
Soft Tissues ◽  
Collagen Fibers ◽  
Bone Collagen ◽  
Cover Slip ◽  
Fibroblast Migration ◽  
Cellular Expression ◽  
Defect Repair

Collagenous biomaterials have been used for growing cells in vitro as well as for augmentation and replacement of hard and soft tissues. The substratum used for culturing cells is implicated in the modulation of phenotypic cellular expression, cellular orientation and adhesion. Collagen may have a strong influence on these cellular parameters when used as a substrate in vitro. Clinically, collagen has many applications to wound healing including, skin and bone substitution, tendon, ligament, and nerve replacement. In this report we demonstrate two uses of collagen. First as a fiber to support fibroblast growth in vitro, and second as a demineralized bone/collagen sponge for radial bone defect repair in vivo.For the in vitro study, collagen fibers were prepared as described previously. Primary rat tendon fibroblasts (1° RTF) were isolated and cultured for 5 days on 1 X 15 mm sterile cover slips. Six to seven collagen fibers, were glued parallel to each other onto a circular cover slip (D=18mm) and the 1 X 15mm cover slip populated with 1° RTF was placed at the center perpendicular to the collagen fibers. Fibroblast migration from the 1 x 15mm cover slip onto and along the collagen fibers was measured daily using a phase contrast microscope (Olympus CK-2) with a calibrated eyepiece. Migratory rates for fibroblasts were determined from 36 fibers over 4 days.

Austrian Veto against European Union Membership Negotiations with Turkey

2020 ◽  
Vol 8 (1) ◽  
pp. 103-122
Author(s):  
Ewa Kaczan-Winiarska
Keyword(s):  
European Union ◽  
European Commission ◽  
Security Policy ◽  
Negotiation Process ◽  
Point Of View ◽  
The European Union ◽  
Strategic Partner ◽  
Key Factor ◽  
European Standards ◽  
The Eu

The Austrian government is extremely sceptical about the accession negotiations which are conducted by the European Commission on behalf of the European Union with Turkey and calls for the negotiation process to end. Serious reservations of Vienna have been raised by the current political situation in Turkey under the rule of President Recep Tayyip Erdogan, as well as by the standards of democracy in Turkey, which differ greatly from European standards. Serious deficiencies in rule of law, freedom of speech and independence of the judiciary, confirmed in the latest European Commission report on Turkey, do not justify, from Vienna’s point of view, the continuation of talks with Ankara on EU membership. In fact, Austria’s scepticism about the European perspective for Turkey has a longer tradition. This was marked previously in 2005 when the accession negotiations began. Until now, Austria’s position has not had enough clout within the European arena. Pragmatic cooperation with Turkey as a strategic partner of the EU, both in the context of the migration crisis and security policy, proved to be a key factor. The question is whether Austria, which took over the EU presidency from 1.7.2018, will be able to more strongly accentuate its reservations about Turkey and even build an alliance of Member States strong enough to block Turkey’s accession process.

scholarly journals Determinants of Corporate Anti-Corruption Disclosure: The Case of the Emerging Economics

2021 ◽  
Vol 13 (6) ◽  
pp. 3462
Author(s):  
Maider Aldaz Odriozola ◽  
Igor Álvarez Etxeberria
Keyword(s):  
Empirical Studies ◽  
Geographical Area ◽  
Control Variable ◽  
Emerging Countries ◽  
Point Of View ◽  
Press Freedom ◽  
Negative Effects ◽  
Key Factor ◽  
Using Data ◽  
Positive Effect

Corruption is a key factor that affects countries’ development, with emerging countries being a geographical area in which it tends to generate greater negative effects. However, few empirical studies analyze corruption from the point of view of disclosure by companies in this relevant geographical area. Based on a regression analysis using data from the 96 large companies from 15 emerging countries included in the 2016 International Transparency Report, this paper seeks to understand what determinants affect such disclosure. In that context, this paper provides empirical evidence to understand the factors that influence reporting on anti-corruption mechanisms in an area of high economic importance that has been little studied to date, pointing to the positive effect of press freedom in a country where the company is located and with the industry being the unique control variable that strengthens this relationship.

Atomistic insights into the structure and elasticity of densified 45S5 bioactive glasses

2021 ◽  
Author(s):  
Youssef Ouldhnini ◽  
Achraf Atila ◽  
Said Ouaskit ◽  
abdellatif hasnaoui
Keyword(s):  
Regenerative Medicine ◽  
Soft Tissues ◽  
Soda Lime ◽  
Model System ◽  
Bioactive Glasses

Glasses have applications in regenerative medicine due to their bioactivity, enabling interactions with hard and soft tissues. Soda-lime phosphosilicate glasses, such as 45S5, represent a model system of bioactive glasses....

Rapid Thermal Processing-Based Heteroepitaxy: Material and Device Challenges

1995 ◽  
Vol 387 ◽  
Author(s):  
J. L. Hoyt ◽  
P. Kuo ◽  
K. Rim ◽  
J. J. Welser ◽  
R. M. Emerson ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Atomic Layer ◽  
Layer Growth ◽  
Point Of View ◽  
Atomic Layer Epitaxy ◽  
Future Research ◽  
Layer By Layer ◽  
Limited Growth ◽  
Measurement And Control

AbstractMaterial and device challenges for Rapid Thermal Processing (RTP) of heterostructures are discussed, focusing on RTP-based epitaxy in the Si/Si1−xGex system. While RTP-based heteroepitaxy offers enhanced processing flexibility, it also poses significant challenges for temperature measurement and control. Several examples of Si/Si1−xGex device structures are discussed from the point of view of the sensitivity of device parameters to variations in layer thickness and composition. The measured growth kinetics for Si and Si1−xGex are then used to estimate growth temperature tolerances for these structures. Demanding applications are expected to require temperature control and uniformity to within 0.5°C.Future research challenges include the fabrication of structures with monolayer thickness control using self-limited growth techniques. Atomic layer epitaxy (ALE) is a well-known example of such a growth technique. In ALE, the wafer is cyclically exposed to different reactants, to achieve layer-by-layer growth. An RTP-based atomic layer epitaxy process, and its application to the growth of CdTe films, is briefly discussed. The extension to Column IV alloys follows readily. The RTP-based process enables self-limited growth for precursor combinations for which isothermal ALE is not feasible.

Effect of Thermal Processing on the Dynamic/Isothermal Crystallization and Cytocompatibility of Polylactic Acid for Biomedical Applications

2021 ◽  
pp. 2100274
Author(s):  
Sandra C. Cifuentes ◽  
Laura Saldaña ◽  
José Luis Gónzalez‐Carrasco ◽  
Rosario Benavente ◽  
Alberto García‐Peñas
Keyword(s):  
Polylactic Acid ◽  
Thermal Processing ◽  
Isothermal Crystallization ◽  
Biomedical Applications
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