Bioglass and bioactive glasses and their impact on healthcare

Glass caused a revolution in healthcare when Bioglass was discovered by Larry Hench. It was the first material to bond with bone, rather than be encapsulated by fibrous tissue, launching the field of bioactive ceramics . Bioglass is also biodegradable. Almost 50 years on from its discovery that revolution continues. Bioactive glasses stimulate more bone regeneration than other bioactive ceramics , which is attributed to their dissolution products stimulating cells at the genetic level. This second discovery has changed the way clinicians, scientists and regulatory bodies think about medical devices and the concept of bioactivity. The original 45S5 Bioglass has only re cently found really widespread use in orthop a edics, having regenerated the bones of more than 1.5 million patients. Its full potential is still yet to be fulfilled. Th is article takes the reader from Hench’s Bioglass 45S5 to its clinical uses and products, before giving examples of non - surgical products that now use Bioglass, from consumer products , such as toothpaste, to cosmetics . Other glasses have also found important healthcare applications, such as borate based glasses that heal chronic wounds. The re volution looks set to continue as new healthcare applications are being found for bioactive glasses, contributing to extending the glass age

Should the oxygen source be considered in the initiation of KCl-induced high-temperature corrosion?

The role of two oxygen sources, oxygen and water vapor, in the initiation of KCl-induced high-temperature corrosion was addressed by studying two high-alloyed commercial materials at 550 \ub0C. The differentiation between the two oxygen sources was implemented with 18O-enriched water and 16O2. Based on the results, the solid-solid reaction between KCl(s) and the protective oxide on the alloy surface appeared to be more responsible for corrosion than the gas-solid reaction between KCl(g) and the protective oxide. Water was more involved in the abovementioned reactions than O2: 18O was the main oxygen isotope found in the formed surface oxides and intermediates

A Retrospective Study on Measures Taken to Prevent Over the Embankment Motor Vehicle Crashes in the Hoopa Area of Northern California

This is a retrospective research paper on measures taken to prevent over-the-embankment (OTB) motor vehicle crashes in the Hoopa Area of Northern California. OTB crashes are defined as any motor vehicle crash that results in that vehicle leaving the roadway and continuing down an embankment. The roadways included for the purposes of this study will be limited to those state highways, local roads, and major spur roads within the approximately 50 mile radius which constitutes the Hoopa Health Association emergency medical services response zone. This study demonstrates that the bluff areas are over-represented for fatal and critical injuries from all motor vehicle crashes in the Hoopa Area. It will further show that the nature of these fatalities is primarily major systems trauma. It is meant to reinforce the conclusion that improved rescue operations and response is not the answer for multiple trauma patients, since even under optimal conditions the time needed for response time, rescue time and the time involved in transport to the nearest contract care emergency unit (52 miles) is far too much time to respond to severe systems trauma. The methodology used in this study was reasonably simple, inexpensive and low-tech surveillance used to predict OTB crash clustering. It was implemented by an Emergency Medical Service Coordinator who had also served as a rescuer. The focal points of the surveillance efforts were the bluff areas that presented a major problem for rescuers because of their height and extreme steepness. The author began a program of video taping the areas where the most severe problems were occurring. He would accompany ambulance units, and record road features, embankments, shoulder widths, and slide marks soon after the accidents had occurred. He began the video taping in 1985. In 1985, coincidental to the video taping campaign, Cal-Trans found itself at fault in two substantial lawsuits in the Hoopa Area. The one was for inadequate road width, and the second was for actions taken by a state road crew at the scene of a diesel spill that caused a double fatality in the North Hoopa Bluffs. At approximately the same time, a Cal-Trans employee developed a means for anchoring guard rails underneath the roadway, using cantilevered steel I-Beams set into ditches under the roadbed. This and the lawsuits and the video campaign resulted in a massive campaign to install guardrail on the bluffs and in widening the roads and other roadbed improvements.Based on the ongoing surveillance of data, since the installation of the guardrail, there is a very strong correlation between the date of installation and a downturn in the number of OTB crashes. The existence of the guardrail has not increased or been a factor in head oncrashes. The cantilevered guardrail seem to be holding up well to brushing impacts and falling rocks along the bluffs without any obvious signs of weakening. There are still embankments that are unprotected. There are some dangerous turns where guardrail weren\\u27t installed completely. These areas will continue to be especially hazardous until they are improved. Lack of visibility of a problem often prevents that problem from being addressed or allows it to be set aside. In OTB crashes multiple systems trauma is most often the killer. Seat belts are a good preventive measure to avoid ejection from the vehicle once the accident is in progress. Other factors in the occurrence of OTB crashes are age of driver, speed and road condition, sex of the driver, familiarity with the road. and sensory impairment from drugs, alcohol, and lack of sleep.The author determined that prevention would reduce fatalities far more than efforts to treat trauma after the fact. He also suggests exploration for altering the environment in an effort to prevent accidental injury rather than or in addition to education efforts

Understanding the Interaction of Potassium Salts with an Ilmenite Oxygen Carrier under Dry and Wet Conditions

This study describes how potassium salts representative of those in bio ash affect the reactivity of the oxygen carrier ilmenite under moist and dry conditions. Ilmenite is a bench-mark oxygen carrier for chemical-looping combustion, a technique that can separate CO2 from flue gases with minimal energy penalty. Different potassium salts were mixed with ilmenite to a concentration of 4 wt % potassium. The salts used were K2CO3, K2SO4, KCl, and KH2PO4. Experiments were performed at 850 \ub0C under alternately oxidizing and reducing conditions in a dry atmosphere or in the presence of steam. Analyses of the oxygen carrier regarding changes in reactivity, structure, and composition followed the exposures. This study showed that salts such as K2CO3, K2SO4, and KCl increase the reactivity of the ilmenite. For the samples mixed with KCl, most of the salt was evaporated. KH2PO4 decomposed into KPO3, forming layers around the ilmenite particles that lead to agglomeration. Additionally, the KPO3 layer was more or less nonpermeable for CO and decreased the reactivity toward H2 significantly in both dry and wet conditions. This decreased reactivity indicates that the concentration of phosphorus in biofuel may have a significant effect on oxygen carrier degradation. It was also observed that the presence of steam changed the chemistry drastically for the nonphosphorus-containing salts. Alkali salts may react with steam, forming volatile KOH that evaporates partly. KOH may also form K-titanates by reaction with the oxygen carrier, leading to segregation of iron and titanium phases in the ilmenite. \ua

The Fast Silver Ion Conducting Solid-State Electrolytes for Deriving Thermodynamic Data

The electromotive force (EMF) method was described and some characteristic examples from the past and recent literatures were reviewed. The important experimental procedures for a successful measurement of an EMF of different galvanic cells at a certain temperature and determination of the thermodynamic properties of chemical compounds from the obtained EMF values were described. A typical galvanic cell arrangement in a furnace was presented. The two most common types of AgI-based solid electrolytes, AgI and RbAg4I5, were discussed in detail. The ionic conduction mechanisms and the application of the solid electrolytes in the EMF cells were described. In this work, we have also conducted EMF measurements using the fast Ag+ ion conducting solid-state electrolyte. The solid-state electrolyte Ag3GeS3I glass and the cathode material Ag4HgSe2I2 were synthesized and electrochemical cell (−)graphite|Ag|Ag3GeS3I glass|Ag4HgSe2I2|graphite(+) was assembled to measure the activity of Ag in the quaternary phase. The extremely low values of activity of silver in Ag4HgSe2I2 in the temperature range 412–482 K indicate that Ag4HgSe2I2 has superionic property. The obtained results and the determined thermodynamic values are presented and discussed

Three Megapixel Ultrasonic Microscope Imaging

Peer reviewe

Glass as a biomaterial: strategies for optimising bioactive glasses for clinical applications

Bioactive glasses were the first synthetic materials to bond to human body tissue, making them ideal for replacing and regenerating bone. Since their first development over half a century ago, many new bioactive glass compositions have been developed for medicine and dentistry. This paper looks at different design strategies employed over the years as well as aspects of glass structure relevant to optimising bioactive glass performance. Statistical compositional series allowed for getting an overview of various compositions and their properties. Since the improvement of structural analysis techniques, particularly solid-state NMR, we can directly relate several bioactive glass properties to the atomic structure, i.e. the spatial arrangement of atoms. Such detailed understanding of the impact of composition and structure on bioactive glass properties enables us to minimise the number of compositions in preclinical and clinical tests needed to confirm positive tissue responses

Glass as a biomaterial: strategies for optimising bioactive glasses for clinical applications

Bioactive glasses were the first synthetic materials to bond to human body tissue, making them ideal for replacing and regenerating bone. Since their first development over half a century ago, many new bioactive glass compositions have been developed for medicine and dentistry. This paper looks at different design strategies employed over the years as well as aspects of glass structure relevant to optimising bioactive glass performance. Statistical compositional series allowed for getting an overview of various compositions and their properties. Since the improvement of structural analysis techniques, particularly solid-state NMR, we can directly relate several bioactive glass properties to the atomic structure, i.e. the spatial arrangement of atoms. Such detailed understanding of the impact of composition and structure on bioactive glass properties enables us to minimise the number of compositions in preclinical and clinical tests needed to confirm positive tissue responses

Polymer-coated bioactive glass S53P4 increases VEGF and TNF expression in an induced membrane model in vivo

The two-stage induced-membrane technique for treatment of large bone defects has become popular among orthopedic surgeons. In the first operation, the bone defect is filled with poly(methyl methacrylate) (PMMA), which is intended to produce a membrane around the implant. In the second operation, PMMA is replaced with autograft or allograft bone. Bioactive glasses (BAGs) are bone substitutes with bone-stimulating and angiogenetic properties. The aim of our study was to evaluate the inductive vascular capacity of BAG-S53P4 and poly(lactide-co-glycolide) (PLGA)-coated BAG-S53P4 for potential use as bone substitutes in a single-stage induced-membrane technique. Sintered porous rods of BAG-S53P4, PLGA-coated BAG-S53P4 and PMMA were implanted in the femur of 36 rabbits for 2, 4 and 8 weeks. The expression of vascular endothelial growth factor (VEGF) and tumor necrosis factor alpha (TNF) in the induced membranes of implanted materials was analyzed with real-time quantitative polymerase chain reaction and compared with histology. Both uncoated BAG-S53P4 and PLGA-coated BAG-S53P4 increase expression of VEGF and TNF, resulting in higher amounts of capillary beds, compared with the lower expression of VEGF and less capillary beads observed for negative control and PMMA samples. A significantly higher expression of VEGF was observed for PLGA-coated BAG-S53P4 than for PMMA at 8 weeks (p <0.036). VEGF and TNF expression in the induced membrane of BAG-S53P4 and PLGA-coated BAG-S53P4 is equal or superior to PMMA, the "gold standard" material used in the induced-membrane technique. Furthermore, the VEGF and TNF expression for PLGA-coated BAG-S53P4 increased during follow-up.Peer reviewe

Copper-releasing, boron-containing bioactive glass-based scaffolds coated with alginate for bone tissue engineering

The aim of this study was to synthesize and characterize new boron-containing bioactive glass-based scaffolds coated with alginate cross-linked with copper ions. A recently developed bioactive glass powder with nominal composition (wt.%) 65 SiO2, 15 CaO, 18.4 Na2O, 0.1 MgO and 1.5 B2O3 was fabricated as porous scaffolds by the foam replica method. Scaffolds were alginate coated by dipping them in alginate solution. Scanning electron microscopy investigations indicated that the alginate effectively attached on the surface of the three-dimensional scaffolds leading to a homogeneous coating. It was confirmed that the scaffold structure remained amorphous after the sintering process and that the alginate coating improved the scaffold bioactivity and mechanical properties. Copper release studies showed that the alginate-coated scaffolds allowed controlled release of copper ions. The novel copper-releasing composite scaffolds represent promising candidates for bone regeneration.Fil: Erol, M. M.. İstanbul Teknik Üniversitesi; TurquíaFil: Mouriño, Viviana Silvia Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Newby, P.. Imperial College London; Reino UnidoFil: Chatzistavrou, X.. Universitat Erlangen-Nuremberg; AlemaniaFil: Roether, Judith A.. Universitat Erlangen-Nuremberg; AlemaniaFil: Hupa, L.. Abo Akademi University; FinlandiaFil: Boccaccini, Aldo R.. Imperial College London; Reino Unido. Universitat Erlangen-Nuremberg; Alemani