Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GLASSES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources
PubMed2004

A radiofrequency glow-discharge-time-of-flight mass spectrometer for direct analysis of glasses.

A radiofrequency (rf) glow-discharge (GD) ion source coupled to a commercial on-axis time-of-flight mass spectrometer (TOFMS) has been developed for the direct analysis of non-conducting samples. Different instrumental configurations of the rf-GD source, including the optional use of a sampler cone and the possibility of allowing electrical floating of the discharge, were evaluated first with a conducting sample. Higher ion signals were obtained when the GD was electrically floating and no sampler cone was used. A homogeneous glass was then analyzed using two different rf-GD configurations--with a sampler cone and discarding the use of the sampler cone. The atomic mass spectra obtained with the TOFMS using both configurations were compared. Analyte signals were systematically higher for the latest mode which avoids the sampler cone. The analytical capability of the proposed rf-GD-TOFMS system for the analysis of thick glasses, up to 6 mm, has been investigated in terms of sensitivity, isotopic ratio accuracy, and mass-resolving power. Different homogeneous glasses (including glasses as thick as 6 mm) have been analyzed and major and minor elements were detected. Isotope ratio accuracies of about +/-1% and mass resolving powers of about 700 were observed.

Electromagnetic Fields↗
PubMed2005

Bacterial biofilm development on hydroxyapatite-coated glass.

Glass plates are frequently used as the substratum in flow cell experiments to allow continuous non-destructive observations of biofilm development via microscopy. The aim of this study was to evaluate hydroxyapatite-coated glass as a substratum for flow cell experiments, in comparison to plain glass, for modelling primary colonization of the tooth surface by Streptococcus sanguis. Glass plates were magnetron sputter coated with hydroxyapatite, producing a thin transparent layer. Biofilm development in the flow cell was recorded using image capture from a microscope, and images were analyzed to determine percentage coverage of the substratum over 24 h. Removal of biofilm by increasing the flow rate was also assessed. No statistically significant differences were detected between S. sanguis biofilms grown on the two different substratum materials. Hence, this work supports the proposal that the conditioning film reduces the influence of substratum surface properties.

Bacterial Adhesion↗
PubMed2002

Posterior segment glass intraocular foreign bodies following car accident or explosion.

BACKGROUND: This study was done to evaluate the results of surgery performed for removal of glass intraocular foreign bodies. METHODS: A prospective study of consecutive cases which have been operated upon for removal of glass intraocular foreign body during the period from May, 1995 to May, 2001 was done. RESULTS: Nine eyes of 9 patients were operated upon during the study period. All were males with an average age of 21.8 years. Unbelted car occupants were the affected persons in 8 out of 9. In all cases, the foreign body was removed with repair of the injury related complications. Forty four percent had 20/50 or better vision. Eighty nine percent had 20/200 or more. Severe retinal injury was associated with poor visual outcome. CONCLUSIONS: Glass foreign bodies need special instruments for extraction. Good visual outcome can be obtained if the retina is not severely affected. Motor vehicle accidents affecting unbelted occupant are the main cause of glass intraocular foreign bodies.

Accidents, Traffic↗
PubMedDate not supplied

Concentration of marine birnavirus from seawater with a glass fiber filter precoated with bovine serum albumin.

In the present study an efficient method for sampling the marine birnavirus (MABV) gene from seawater was developed. MABV gene was monitored by a specific polymerase chain reaction. When Millipore filters were used, MABV was efficiently collected on a filter with 0.05- micro m pore size. When both millipore and glass fiber filters were used, MABV was recovered from both filters. Use of plain glass fiber filters resulted in poor recovering efficiency. However, coating the glass fiber filters with 1% bovine serum albumin trapped MABV efficiently. Combining concentration on glass fiber filters with polymerase chain reaction is quantitative, economic and fast, suggesting that this method can be used to detect genetically identified fish disease viruses, algal viruses, and phages.

Adsorption↗
PubMed2005

Primary osteoblast cell response to sol-gel derived bioactive glass foams.

Bioactive glass macroporous structures were developed in this work to be used as scaffolds for bone tissue engineering applications. A sol-gel route was used to obtain glass foams with the introduction of a gas phase in the solution and by vigorous agitation of the sol-gel solution that contains a foam agent. Stable and homogeneous foams were formed near the gelation point, which were than dried and heat-treated. Macroporous structures with interconnected pores of up to 500 mu m, porosity as high as 88% and specific surface area of 92 m(2)/g were obtained. The porous glasses were tested in osteoblast cultures to evaluate adhesion, proliferation, collagen and alkaline phosphatase production. Osteoblast proliferation was higher in the presence of the foams as well as was the collagen secretion, when compared to control. The alkaline phosphatase production was not altered. Viable osteoblasts could be seen inside the foams, suggesting that the produced porous glass foams are a promising materials for bone repair, since it provides a good environment for the adhesion and proliferation of osteoblasts.

Alkaline Phosphatase↗
PubMed2005

Microstructural and in vitro characterization of SiO2-Na2O-CaO-MgO glass-ceramic bioactive scaffolds for bone substitutes.

In the present research work, the preparation and characterization of bioactive glass-ceramic scaffolds for bone substitutes are described. The scaffolds were prepared by starch consolidation of bioactive glass powders belonging to the SiO2-Na2O-CaO-MgO system using three different organic starches (corn, potatoes and rice) as reported in a previous screening process. The scaffolds, characterized by scanning electron microscopy, showed a porous structure with highly interconnected pores. The pores sizes assessed by mercury intrusion porosimetry put in evidence the presence of pores of 50-100 microm. The structure of the scaffolds was investigated by X-ray diffraction and revealed the glass-ceramic nature of the obtained material. The mechanical properties of the scaffolds were evaluated by means of compressive tests on cubic samples and the obtained results demonstrated their good mechanical strength. The in vitro bioactivity of the scaffolds was tested by soaking them in a simulated body fluid (SBF) and by subsequently characterizing the soaked surfaces by SEM, EDS and X-ray diffraction. Good in vitro bioactivity was found for the starting glass and for the obtained scaffolds. Moreover, the scaffold bioresorption, tested by measuring the samples weight loss in SBF at different periods of time, showed a partial resorption of the scaffolds. Cell culture testing of the three different scaffolds indicated no differences in cell number and in alkaline phosphatase activity; the morphology of the osteoblasts showed good spreading, comparable to bulk material which was used as the control.

Body Fluids↗
PubMed2006

Gene activation by bioactive glasses.

Bioactive glasses have been shown to regulate gene expression in both hard and soft tissue repair. New resorbable bioactive glass constructs are now being developed that can influence gene expression in the local environment by manipulating material properties such as the surface chemistry, topography and the release of dissolution ions. The success of these scaffolds, however, may depend upon a greater understanding of the bioactive glass stimulated gene expression pathways. This will allow the construction of tissue specific scaffolds with tailored surface chemistry, topography and ion release rates. This paper summarises the advances made in understanding gene expression in response to bioactive glasses and discusses the future steps required for further insights into these molecular mechanisms.

Animals↗
PubMed2006

Macroporous bioactive glass-ceramic scaffolds for tissue engineering.

Highly bioactive scaffolds for tissue engineering were synthesized using a glass belonging to the SiO2-CaO-K2O (SCK) system. The glass SCK was prepared by a traditional melting-quenching route and its bioactivity was assessed by in vitro tests in a simulated body fluid (SBF). The glass was ground and sieved to obtain powders of specific size that were subsequently mixed with polyethylene particles of two different dimensions. The powders were then uniaxially pressed to obtain a crack free green compact that was thermally treated to remove the organic component and to sinter the inorganic phase. The obtained biomaterial was characterised by means of X-ray Diffraction, SEM equipped with EDS, mercury intrusion porosimetry, density measurements, image analysis, mechanical tests and in vitro evaluations. A glass-ceramic macroporous scaffold with a homogenously distributed and highly interconnected porosity was obtained. The amount and size of the introduced porosity could be tailored using various amounts of polyethylene powders of different size.

Biocompatible Materials↗
PubMed2006

Behaviour of MG-63 osteoblast-like cells on wood-based biomorphic SiC ceramics coated with bioactive glass.

The aim of this study was to test the in vitro cytotoxicity of wood-based biomorphic Silicon Carbide (SiC) ceramics coated with bioactive glass, using MG-63 human osteoblast-like cells, with a view to their application in bone implantology. To better understand the scope of this study, it should be taken into account that biomorphic SiC ceramics have only recently been developed and this innovative product has important properties such as interconnected porosity, high strength and toughness, and easy shaping. In the solvent extraction test, all the extracts had almost no effect on cellular activity even at 100% concentration, and cells incubated in the bioactive glass-coated SiC ceramics extracts showed a proliferation rate similar to that of the Thermanox control. There were no significant differences when the cellular attachment response of the cells on the wood-based biomorphic SiC ceramics, uncoated or coated with bioactive glass, was compared to the one exhibited by reference materials like Ti6Al4V and bulk bioactive glass. This fact looks very promising for biomedical applications.

Biomimetic Materials↗
PubMed2006

Effect of calcium phosphate glass on bone formation in calvarial defects of Sprague-Dawley rats.

The purpose of this study was to investigate the bone regenerative effect of calcium phosphate glass in vivo. We prepared two different sizes of calcium phosphate glass powder using the system CaO-CaF2-P2O5-MgO-ZnO; the particle size of the powders were 400 microm and 40 microm. 8 mm calvarial critical-sized defects were created in 60 male Sprague-Dawley rats. The animals were divided into 3 groups of 20 animals each. Each defect was filled with a constant weight of 0.5 g calcium phosphate glass powder mixed with saline. As controls, the defect was left empty. The rats were sacrificed 2 or 8 weeks after postsurgery, and the results were evaluated using radiodensitometric and histological studies; they were also examined histomorphometrically. When the bigger powders with 400 microm particle were grafted, the defects were nearly completely filled with new-formed bone in a clean healing condition after 8 week. When smaller powders with 40 microm particle were transplanted, new bone formation was even lower than the control group due to a lot of inflammatory cell infiltration. It was concluded that the prepared calcium phosphate glass enhanced the new bone formation in the calvarial defect of Sprague-Dawley rats and it is expected to be a good potential materials for hard tissue regeneration. The particle size of the calcium phosphate was crucial; 400 microm particles promoted new bone formation, while 40 microm particles inhibited it because of severe inflammation.

Animals↗
PubMed1989

Adsorption of proteins onto glass surfaces and its effect on the intensity of circular dichroism spectra.

Errors in analyzing CD spectra of proteins arising from adsorption loss onto glass surfaces were examined for six proteins: apolipoproteins A-I and E, fibronectin, bovine serum albumin, insulin, and glucagon. Among these, the glycoproteins, apolipoprotein E and fibronectin, adsorbed most onto glass surfaces. Their CD intensities decreased by about 50% when proteins were diluted serially from 1 to 0.01 mg/ml in regular glass-ware and CD was measured in uncoated cells. The other proteins, except glucagon, also showed a certain degree of adsorption. Thus, adsorption loss of proteins onto glass surfaces is common and may lead to serious errors in experimental results. Adsorption can be minimized by using plastic containers and pipet tips, coating the cell with silicone, and wetting the cell before adding the protein solution.

Adsorption↗
PubMed1986

Glass-forming tendency and stability of the amorphous state in the aqueous solutions of linear polyalcohols with four carbons. I. Binary systems water-polyalcohol.

All the aqueous solutions of linear saturated polyalcohols with four carbons have been investigated at low temperature. Only ice has been observed in the solutions of 1,3-butanediol and 1,2,3- and 1,2,4-butanetriol. For same solute concentration, the glass-forming tendency on cooling is highest with 2,3-butanediol, where it is comparable to that with 1,2-propanediol, the best solute reported to date. However, the quantity of ice and hydrate crystallized is particularly high on slow cooling or on subsequent rewarming. The highest stability of the amorphous state is observed on rewarming the 1,2-butanediol and 1,3-butanediol solutions. With respect to this property, these compounds come just after 1,2-propanediol and before all the other compounds studied so far. They are followed by dimethylsulfoxide and 1,2,3-butanetriol. The glass-forming tendency of the 1,3-butanediol solutions is also very high; it is third only to that of 1,2-propanediol and 2,3-butanediol. The glass-forming tendency is a little smaller with 1,2-butanediol, but it is cubic instead of ordinary hexagonal ice which crystallizes on cooling rapidly with 35% 1,2-butanediol. Cubic ice is thought to be innocuous. A gigantic glass transition is observed with 45% of this strange solute. 1,4-Butanediol, 45% also favors cubic ice greatly. Therefore, 1,2- and 1,3-butanediol with comparable physical properties are perhaps as interesting as 1,2-propanediol for cryopreservation of cells or organs by complete vitrification. Together with 1,2-propanediol, 1,2- and 1,3-butanetriol, 1,2,3-butanetriol, and perhaps 2,3-butanediol provide an interesting battery of solutions for cryopreservation by vitrification.

Alcohols↗
PubMed1993

The concentration and isotopic composition of carbon in basaltic glasses from the Juan de Fuca Ridge, Pacific Ocean.

The abundance and 13C/12C ratios of carbon were analyzed in basaltic glass from twenty locations along the Juan de Fuca Ridge using a 3-step combustion/extraction technique. Carbon released during the first two combustion steps at 400-500 degrees C and 600-650 degrees C is interpreted to be secondary, and only the carbon recovered during a final combustion step at approximately 1200 degrees C is thought to be indigenous to the samples. For carbon released at approximately 1200 degrees C, glasses analyzed as 1-2 mm chips contained 23-146 ppm C with delta 13C values of -4.8 to -9.3%, whereas samples crushed to 38-63 microns or 63-90 microns yielded 56-103 ppm C with delta 13C values of -6.1 to -9.2%. The concentrations and isotopic compositions of the primary carbon dissolved in the glasses and present in the vesicles are similar to those previously reported for other ocean-ridge basalts. The Juan de Fuca basaltic magmas were not in equilibrium with respect to carbon when they erupted and quenched on the sea floor. Evidence of disequilibrium includes (1) a large range of carbon contents among glasses collected at similar depths, (2) a highly variable calculated carbon isotopic fractionation between melt and vapor determined by comparing crushed and uncrushed splits of the same sample, and (3) a lack of correlation between vesicle abundance, carbon concentration, and depth of eruption. Variations in carbon concentration and delta 13C ratios along the ridge do not correlate with major element chemistry. The observed relationship between carbon concentrations and delta 13C values may be explained by late-stage, variable degrees of open-system (Rayleigh-like) degassing.

Carbon↗
PubMed1982

1086 consecutive injuries caused by glass.

A prospective study of 1086 consecutive injuries caused by glass showed that the mean age of the patients was 15 years and there was a 7 : 3 male to female ratio. The home (35 per cent), public places (31.3 per cent) and places of work (21.1 per cent) were the main locations where these accidents occurred. Although most of the injuries were mild, 3 case histories illustrate that some of them were extremely serious. 4.6 per cent of patients requiring immediate admission to hospital. Extrapolation of the figures indicates that approximately 210,000 people attend hospital each year in England and Wales for treatment of an injury caused by glass. The annual cost to the National Health Service is about 7,500,000 pounds but the full financial implications of these injuries in terms of compensation and insurance payments must be much greater. Suggestions are made of ways to reduce the incidence of these injuries from road traffic accidents and accidents with plate glass and glass containers.

Accident Prevention↗
PubMed1989

Fracture resistance of posterior teeth restored with glass ionomer-composite resin systems.

This study compared the fracture resistance of posterior teeth restored with one of four composite resin systems or amalgam. Mesio-occlusodistal cavity preparations were placed in 50 maxillary premolars. Dimensions of the preparation were such that remaining tooth structure was weakened. Five groups of 10 specimens each were designated as follows: I, amalgam; II, Ketac-Bond glass-ionomer base; III, Ketac-Silver glass-ionomer base; IV, GC lining cement glass-ionomer base; and V, Tenure dentinal bonding agent. Specimens in groups II through V were restored with P-30 posterior composite resin. Testing was accomplished by applying an occlusal load to the point of failure for each specimen. Results indicated no significant difference among restorative systems in resistance to cuspal fracture. These findings suggest that neither Tenure nor glass-ionomer cement used in conjunction with posterior composite resin strengthen weakened cusps to any greater extent than does amalgam.

Bicuspid↗
PubMed1989

Glass-ionomer cement film thickness and working time.

Reports on film thickness for adhesive glass-ionomer cements have not been consistent, and confusion exists relative to proper working times. In this investigation, film thickness was measured over a range of times for three glass-ionomer cements by using a traditional ADA glass plate technique and a simulated clinical cementation technique with castings and dies. The cements were examined from 60 seconds to 255 seconds from the start of mix. Results indicated that the simulated clinical technique generally provided less film thickness. No significant differences in film thickness were found between the brands of cement through 240 seconds with film thickness ranging from 7.24 to 20.5 microns. Greater differences between the cements were observed with the ADA technique beyond 135 seconds from the time of mix. Relative to film thickness, working times would appear to be greater than previously reported for glass-ionomer cements.

Chemical Phenomena↗
PubMed1993

Marginal leakage of visible light-cured glass ionomer restorative materials.

This study examined the sealing of two visible light-cured glass ionomer restorative materials and a conventional glass ionomer. Class V cavity preparations were completed at the cementoenamel junction on the facial and lingual surfaces of extracted human molars. The cavity preparations were restored with either VariGlass VLC, GC Fuji II LC, or GC Fuji II glass ionomer cements. The restored teeth were thermocycled, immersed in fuchsin dye for 24 hours, sectioned, and evaluated with a measuring microscope. No microleakage occurred at the enamel/glass ionomer or dentin/glass ionomer cement interfaces of any samples, but the enamel adjacent to the VariGlass glass ionomer cement restorations exhibited crazing and staining.

Acrylic Resins↗
PubMed1987

Tissue response to retrograde root fillings in the ferret canine: a comparison of a glass ionomer cement and gutta-percha with sealer.

Tissue healing was compared after apicectomy and filling of ferret lower canines with glass ionomer (Ketacfil) or gutta-percha/sealer (Tubliseal). Both materials provoked an inflammatory response after 7 days, but the response to glass ionomer was less severe. The response after 28 days was different. Mild inflammation related to the gutta-percha was still present, but no inflammation was found in relation to the glass ionomer. Bone infill was quite advanced in all specimens at 28 days but was more complete in the glass ionomer specimens, with intimate contact between the bone and cement.

Animals↗