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PubMed1977

Asbestos and glass fibres in bacterial mutation tests.

Asbestos fibres are carcinogenic in man and experimental animals but fine glass fibres are known, at present, only to be carcinogenic in experimental animals. Asbestos and glass fibres have been studied in mutation tests using auxotrophic strains of Escherichia coli and Salmonella typhimurium. The mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments. However, no mutagenic activity was found to be associted with any of the asbestos and glass fibres tested over a wide range of concentrations. The implications of these findings for the mode of action of asbestos and glass fibres as carcinogens are discussed.

Asbestos↗
PubMed1994

Microstructural characterization of glass-reinforced hydroxyapatite composites.

The influence of phosphate-based glasses and a bioactive silica glass on the sintering mechanism of hydroxyapatite was studied over a wide range of temperatures. The composites were microstructurally characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Small additions of phosphate-based glasses proved to be beneficial to the sintering process and fully dense materials were obtained. A significant improvement in mechanical properties was achieved. beta-TCP and alpha-TCP were found in the microstructure depending on the sintering temperature. Additions of bioactive glass led to the development of calcium phosphate silicate.

Biocompatible Materials↗
PubMed1983

Glass-plastic push-pull cannula system for regional perfusion of sites in the brain.

A new non-metallic push-pull cannula device is described for the localized perfusion of brain sites in the rat or other animal. Comprised entirely of glass and plastic materials, the cannula is intended for usage in an experiment in which the presence in tissue of metal tubing for delivery of perfusate is methodologically inappropriate. The main features of the cannula include its light weight, a Delrin pedestal base, a micro-glass guide tube, a polyethylene stylet, plastic spacers for adjustment of depth of perfusion, a protective cap for the chronic maintenance of the preparation, low cost and re-usability. The push-pull cannula is of concentric design and is fashioned from glass capillary and polyethylene tubing which are bonded at their common junctions by an epoxy cement. During a push-pull perfusion a special perfusion cap is used not only to hold the cannula firmly in place but also to protect the glass components from external damage. To further coincide with the metal-free requirements of the preparation, bone screws of nylon are used during the surgical implantation of the pedestal base. A prototype experiment illustrating its use in an unrestrained animal also is presented. The special applications for this cannula system are discussed which include its usage in experiments in either the anesthetized or unanesthetized rat exposed to microwave radiation where the presence of metal in the field would result in unwanted 'hot spots' in the cerebral tissue.

Animals↗
PubMed1992

Neutrophil, glass-adherent, nitroblue tetrazolium assay gives early indication of immunization effectiveness in rainbow trout.

Neutrophil activity in rainbow trout (Oncorhynchus mykiss) is increased upon antigenic stimulation with the Yersinia ruckeri O-antigen bacterin. The characteristics of neutrophil attachment to glass and nitroblue tetrazolium (NBT) staining were used to determine the effectiveness of immunization programs with fingerling rainbow trout. Fish immunized by intraperitoneal injection with doses of 100, 10, or 1 microgram of the bacterin showed the highest responses in that order in numbers of glass adherent, NBT-positive neutrophils. Studies on the kinetics of the occurrence of numbers of glass-adherent, NBT-positive staining cells from the fish injected with the 10 micrograms dose showed the numbers of positive cells were largest on Day 2 after injection. The specific immune response was confirmed by demonstrating the presence of plaque-forming cells by the passive hemolytic plaque assay and the rise in humoral antibody titers by passive hemagglutination 12 days after injection. The effects of immunization in trout could be detected earlier by using the neutrophil glass adherence and NBT reduction assays than by using assays based on observations of the specific immune response.

Animals↗
PubMed2006

Physicochemical degradation studies of calcium phosphate glass ceramic in the CaO-P2O5-MgO-TiO2 system.

The aim of this work was to evaluate the in vitro degradation behaviour of a 45CaO-37P(2)O(5)-5MgO-13TiO(2) (mol.%) glass ceramic, under two different simulated physiological conditions: normal physiological pH 7.4, and pH 3.0, which was designed to simulate the acidic conditions produced by osteoclast cells. The in vitro testing was carried out at 37 degrees C for up to 42 days for the pH 7.4 solution and for up to 1 day for the pH 3.0 solution. The incorporation of TiO(2) into the glass structure leads to the precipitation of specific crystalline phases in the glass matrix, namely alpha- and beta-Ca(2)P(2)O(7), TiP(2)O(7) and CaTi(4)(PO(4))(6). The degradation testing at pH 3.0 showed a higher weight loss compared with degradation testing at pH 7.4; the weight loss under the acidic condition after 1 day (24 h) was about 10 times higher than the weight loss after 42 days of immersion at pH 7.4. The ionic release profile of Ca(2+), PO(4)(3-), Mg(2+) and Ti(4+) showed a continuous increase in concentration over all immersion times for both testing solutions. After 1 day of immersion at pH 3.0, the concentration levels of Mg(2+), Ca(2+), PO(4)(3-) were about six times higher than the levels achieved after 42 days of immersion at pH 7.4. The glass ceramic showed similar degradation to hydroxyapatite, and therefore has potential to be used in certain clinical applications where relatively slow resorption of the implant and replacement by bone is required, e.g. cranioplasty.

Biocompatible Materials↗
PubMed2004

Video-assisted thoracic surgery for pure ground-glass opacities 2 cm or less in diameter.

BACKGROUND: Small, well-circumscribed pure ground-glass opacities on high-resolution computed tomography can represent either localized bronchioloalveolar carcinoma without foci of active fibroblastic proliferation, or atypical adenomatous hyperplasia. Since neither lesion displays lymph node metastasis, excellent prognosis can be expected even with limited surgical resection. In this study, video-assisted thoracic surgery was performed for patients with pure ground-glass-opacity to evaluate efficacy for both diagnostic and therapeutic purposes. METHODS: Thirty-nine patients with pure ground-glass opacity less than or equal to 2 cm in diameter (62 lesions) underwent video-assisted thoracic surgery with wedge resection as primary therapy. Histologic diagnoses were made according to Noguchi classifications. RESULTS: Single lesions were observed in 30 patients, with multiple lesions (mean, 4 lesions) in 9 patients. Twenty-eight patients underwent wedge resection. Seven patients underwent lobectomy or segmentectomy for technical reasons. Four patients underwent conversion of wedge resection to lobectomy (due to active fibroblastic proliferation in 2 patients, and other reasons in 2 patients). All procedures were performed under videoscopic observation. Histologic diagnoses comprised localized bronchioloalveolar carcinoma without active fibroblastic proliferation either alone or in combination with atypical adenomatous hyperplasia in 29 patients, atypical adenomatous hyperplasia in 8 patients, and localized bronchioloalveolar carcinoma with active fibroblastic proliferation in 2 patients. All patients with localized bronchioloalveolar carcinoma underwent follow-up for a median period of 29.3 months, and have survived without sign of recurrence. CONCLUSIONS: Video-assisted thoracic surgery may be appropriate for management of small pure ground-glass opacities.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2005

11C-acetate positron emission tomography imaging for lung adenocarcinoma 1 to 3 cm in size with ground-glass opacity images on computed tomography.

BACKGROUND: Positron-emission tomography (PET) with 18F-fluorodeoxy-glucose (FDG) frequently gives false-negative results for well-differentiated adenocarcinomas of the lung, especially, those with ground-glass opacity images. Recently, PET with 11C-acetate (AC) has been reported to detect slow-growing tumors that have failed to be identified by FDG-PET, such as well-differentiated hepatocellular carcinomas and prostate cancers. To determine the usefulness of AC-PET in detecting well-differentiated adenocarcinomas of the lung, we performed both AC-PET and FDG-PET on pulmonary nodules with ground-glass opacity images on computed tomography (CT). METHODS: Fifty-four pulmonary nodules 1 to 3 cm in size, which showed ground-glass opacity images over their whole or peripheral area on CT, were examined by both AC-PET and FDG-PET. RESULTS: Thirty-seven nodules were adenocarcinoma of the lung, while 17 were inflammatory. Of the 37 adenocarcinomas, 19 (51%) were positively identified by AC-PET and 14 (38%) by FDG-PET. Of the 23 adenocarcinomas which were not identified by FDG-PET, 8 (35%) were positively identified by AC-PET; all were well-differentiated adenocarcinomas. Of the 17 inflammatory nodules, 8 were chronic and 9 were acute ones. While none of the 8 chronic inflammatory nodules were identified by either technique, 9 acute ones showed a variety of the results with AC- and FDG-PET. CONCLUSIONS: AC-PET detected approximately one third of well-differentiated adenocarcinomas of the lung which were not identified by FDG-PET. AC-PET could be useful to diagnose pulmonary nodules with ground-glass opacity images which were not identified by FDG-PET.

Acetates↗
PubMed2006

Multiple lung adenocarcinomas showing ground-glass opacities on thoracic computed tomography.

It is difficult to distinguish multiple primary lung cancers from pulmonary metastasis. We experienced a case of surgically resected lung tumors that showed multiple ground-glass opacities on thoracic computed tomographic scan. There were eight nonsolid and two part-solid ground-glass opacities in the bilateral lungs. Surgical resection was performed because all tumors had a ground-glass opacity appearance on computed tomographic scan, which is compatible with a finding of primary lung adenocarcinoma. The postoperative pathologic diagnoses were two cases of invasive adenocarcinoma, six cases of bronchioloalveolar carcinoma, and eight cases of atypical adenomatous hyperplasia. The patient remains alive without any evidence of recurrence 40 months after surgery. A ground-glass opacity appearance on computed tomographic scan could be interpreted as supportive evidence for multiple primary lung adenocarcinoma rather than pulmonary metastases.

Adenocarcinoma↗
PubMed2006

Extracellular matrix formation and mineralization on a phosphate-free porous bioactive glass scaffold using primary human osteoblast (HOB) cells.

Sol-gel derived bioactive glasses of the 70S30C (70mol% SiO2, 30mol% CaO) composition have been foamed to produce 3D bioactive scaffolds with hierarchical interconnected pore morphologies similar to trabecular bone. The aim of this study was to investigate primary human osteoblast response to porous bioactive glass scaffolds. The scaffolds supported osteoblast growth and induced differentiation, within the 3-week culture period, as depicted by enhanced ALPase enzymatic activity, without the addition of supplementary factors such as ascorbic acid, beta-glycerophosphate and dexamethasone. This is the first time this has been observed on a bioactive glass that does not contain phosphate. Deposition of extracellular matrix was also confirmed by enhanced production of the extracellular matrix protein collagen type I. SEM showed indications of mineralized bone nodule formation without the addition of growth factors. The 70S30C bioactive glass scaffolds therefore fulfil many of the criteria for an ideal scaffold for bone tissue engineering applications.

Calcification, Physiologic↗
PubMed2004

Citrate increases glass transition temperature of vitrified sucrose preparations.

The aim of this study was to investigate the effect of sodium citrate on the properties of dried amorphous sucrose glasses. Addition of sodium citrate to a sucrose solution followed by freeze-drying or convective drying resulted in a glass transition temperature (Tg) that was higher than the well-studied sucrose Tg. This result was obtained either at reduced water content of the analysed sample or by removal of water during Modulated DSC analysis. After removal of the remaining water ( < 3.5% w/w), a Tg of approximately 105 degrees C was obtained at a mass ratio of sodium citrate to sucrose of 0.3. FTIR analysis showed a similar increase in Tg as was found with Modulated DSC analysis. The Tg values were derived from breaks in the vibrational frequency vs. temperature plots in the OH stretching and bending regions. Elevated average strength of hydrogen bonding in the sucrose/citrate glass was concluded from the downshift of the OH stretching band of 25 cm(-1) and from the reduced wavenumber temperature coefficient (WTC). The antisymmetric carboxylate stretch of citrate sensed the glass transition of the mixture, from which we conclude that citrate interacts with the sucrose OH via its carboxylate groups.

Calorimetry, Differential Scanning↗
PubMed2004

Strength, fracture toughness and microstructure of a selection of all-ceramic materials. Part I. Pressable and alumina glass-infiltrated ceramics.

OBJECTIVE: The present study, divided into two parts, aimed to compare the strength, fracture toughness and microstructure of a range of all-ceramic materials. In part I, three hot-pressed glass-ceramics (IPS-Empress, Empress 2 and a new experimental ceramic) and alumina glass-infiltrated ceramics (In-Ceram Alumina), processed by both slip casting and dry pressing, were compared. METHODS: Tensile strength was appraised on 10 bar-shaped specimens (20 x 4 x 1.2 mm3) for each material with the three-point bending method; the fracture toughness was measured from 20 specimens (20 x 4 x 2 mm3), by using the indentation strength technique. Data were compared with ANOVA and the Sheffé post hoc test (p = 0.05). The volume fraction of each phase, the dimensions and shapes of the grains, porosity and the crack patterns were investigated using SEM. RESULTS: The average and standard deviation in strength (MPa) and fracture toughness (MPa m(1/2)) were: IPS-Empress 106(17)1, 1.2(0.14)1; Empress 2 306(29)2, 2.9(0.51)2, new experimental ceramic 303(49)2, 3.0(0.65)2, In-Ceram Alumina dry-pressed 440(50)2, 3.6(0.26)2, In-Ceram Alumina slip 594(52)3, 4.4(0.48)3. Values with the same superscript number showed no significant statistical difference. Microscopy revealed the relationship between the glass matrix and the crystalline phase and the characteristics of the latter were correlated to the strengthening and toughening mechanisms of these glass-ceramics. SIGNIFICANCE: The mechanical properties and microstructure of core materials have been advocated as crucial to the clinical long-term performance of all-ceramic dental restorations. This investigation provides the clinician with data regarding strength, fracture toughness and microstructure of a broad range of current materials.

Aluminum Silicates↗
PubMed2006

Cerium and boron chemistry in doped borosilicate glasses examined by EELS.

Spatially resolved measurements of boron coordination and cerium valency in a doped borosilicate glass with crystalline nano-precipitates are described. The fine structure of the boron K-edge and the white-line ratio of the cerium M-edge doublet were evaluated from EELS line scans. Due to high beam sensitivity it was found that reliable boron-coordination measurements in some of the glasses studied required extrapolation of results acquired after different periods of irradiation back to a zero-irradiation. However, borosilicates that contained heavy alkali atoms were found to suffer very little structural change. The Ce valency of a 4% (molar) doped alkali-borosilicate glass was found to be mixed +III/+IV in the glass matrix and purely +IV (indicative of CeO2) in the precipitates. A significant dependency of the valence results on the data processing method was found and explained.

Journal Article↗
PubMedDate not supplied

Multinuclear NMR studies on the sol-gel preparation of sodium aluminophosphate glasses.

Sodium aluminophosphate gels and glasses in the system NaPO(3)-Al(2)O(3) with P/Al ratios ranging from 9:1 to 1:1 have been synthesized by a novel sol-gel route based on the reaction of aluminum lactate with sodium polyphosphate in aqueous solution. The route from the solution to the gel and the final glass was monitored in situ by liquid and solid state NMR techniques, characterizing the influence of composition and pH on the hydrolysis, polymerization, and vitrification processes. The site distribution in the xerogels is strongly influenced by the gel-processing temperature. At temperatures near 150 degrees Celsius ligation with lactate groups can be nearly suppressed, resulting in maximum Al/P connectivity in the gel. Annealing the gels at temperatures near 400 degrees Celsius produces significant structural rearrangements, resulting in a glassy network that has close structural similarity to the glasses derived from the usual melt-cooling procedure at 1100-1450 degrees Celsius. This has been confirmed by extensive (27)Al, (31)P and (23)Na MAS NMR as well as (27)Al[(31)P] and (27)Al [(1)H] double resonance experiments. Compared to melt-cooling, the sol-gel process permits a significant extension of the glass-forming region towards higher alumina contents.

Journal Article↗
PubMed2005

Endocrine control of Anguilla anguilla glass eel dispersal: effect of thyroid hormones on locomotor activity and rheotactic behavior.

Dispersal, one of the most important processes in population ecology, is an issue linking physiological and behavioral features. However, the endocrine control of animal dispersal remains poorly understood. Here, we tested whether and how thyroid hormones may influence dispersal in glass eels of Anguilla anguilla, by testing their influence on locomotor activity and rheotactic behavior. Glass eels were caught during their estuarine migration and treated by immersion in either a l-thyroxine (T(4)) or a thiourea (TU) solution. As measured by radioimmunoassay, T(4) and TU treatments induced, respectively, increased and decreased whole-body thyroid hormone levels relative to untreated controls. We tested a total of 960 glass eels distributed into control, and T(4) and TU treatment groups, on their swimming behavior in experimental flume tanks equipped with upstream and downstream traps that allowed us to concurrently measure both the locomotor activity and the rheotactic behavior. Compared to controls, locomotor activity significantly increased among the hyperthyroid, T(4)-treated eels, but significantly decreased among the hypothyroid, TU-treated eels. The results on rheotactic behavior suggested a more complex regulatory mechanism, since TU but not T(4) treatment significantly affected rheotactic behavior. The influence of thyroid hormones on locomotor activity suggests a central role for these hormones in the regulation of mechanisms leading to the colonization of continental habitats by glass eels. Thyroid hormones are also implicated in the control of locomotor activity in mammals and migratory behavior in birds, suggesting that these hormones represent conserved, proximate mediators of dispersal in vertebrates.

Anguilla↗
PubMed2003

Protein immobilization on plasma-polymerized ethylenediamine-coated glass slides.

For protein chip construction, protein immobilization on the surface of the glass slide is essential. It was previously reported that glass slides are embedded with chemicals that contain primary amines and aldehydes for protein immobilization. We fabricated a plasma-polymerized ethylenediamine (PPEDA)-coated slide that exposed primary amines. For the plasma polymer deposition on the glass slide, the inductively coupled plasma (ICP) power was found to be a critical factor in sustaining a high density of amine on the surface of the PPEDA films. We prepared PPEDA-coated slides at three different ICP powers (3, 30, or 70 W). In the slide that was prepared at a low ICP power (3 W), we detected a high density of primary amine. Therefore, the fluorescein isothiocyanate-conjugated immunoglobulin G (IgG) was highly immobilized to the PPEDA-coated slide that was prepared at the low ICP power. For protein immobilization, 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) was used as a cross-linker. The immobilization of the protein to the PPEDA-coated slide was carried out by consecutive incubations with 1 mg/ml EDC for 5 min and 0.1 mg/ml IgG for 1 h. This efficiently produced the functionally active protein-immobilized slide. Therefore, this work shows that the plasma technique can be applied to produce a high-quality glass surface for the immobilization of proteins and other materials.

Ethylenediamines↗
PubMed2002

"Early" peripheral lung cancer: prognostic significance of ground glass opacity on thin-section computed tomographic scan.

BACKGROUND: The number of peripherally located lung cancers with an excellent prognosis has been increasing, possibly due to the introduction of computed tomography for lung cancer screening in Japan. The concept of peripherally located "early lung cancer" remains controversial. METHODS: A retrospective study was conducted on 1,540 lung cancers resected at our institute between May 1992 and December 2000. The sizes of solid attenuation and ground glass opacity were evaluated radiologically and the relationships between radiologic findings and clinicopathologic features were investigated to define peripheral early lung cancer. RESULTS: Sixty-nine (4.4%) lung cancers showed a large ground glass opacity component on thin-section computed tomographic scan. The maximum tumor dimension ranged from 6 to 41 mm, and all tumors were clinical stage I. Forty-seven patients were diagnosed as having bronchioloalveolar carcinoma pathologically. None of the tumors showed lymph node involvement or lymphatic invasion. Only two showed vascular invasion, but all were pathologic stage I disease. Most of the lung cancers that showed pure ground glass opacity were bronchioloalveolar carcinoma. CONCLUSIONS: Peripheral lung nodules with a large ground glass opacity component on thin-section computed tomographic scan, which do not disappear during follow-up, tend to be bronchioloalveolar carcinomas or minimally invasive adenocarcinomas of the lung. These findings warrant a feasibility study of limited surgical resection for such lung tumors.

Adenocarcinoma↗
PubMed2002

The glass transition temperature of mixtures of trehalose and hydroxyethyl starch.

Although mixtures of HES and sugars are used to preserve cells during freezing or drying, little is known about the glass transition of HES, or how mixtures of HES and sugars vitrify. These difficulties may be due to the polydispersity between HES samples or differences in preparation techniques, as well as problems in measuring the glass transition temperature (T(g)) using differential scanning calorimetry (DSC). In this report, we examine the T(g) of mixtures of HES and trehalose sugar with <1% moisture content using DSC measurements. By extrapolating these measurements to pure HES using the Gordon-Taylor and Fox equations, we were able to estimate the T(g) of our HES sample at 44 degrees C. These results were additionally confirmed by using mixtures of glucose-HES which yielded a similar extrapolated T(g) value. Our approach to estimating the glass transition temperature of HES may be useful in other cases where glass transitions are not easily identified.

Calorimetry, Differential Scanning↗
PubMed2003

The nature of the structural gradient in epoxy curing at a glass fiber/epoxy matrix interface using FTIR imaging.

The curing process of an epoxide system was studied at the interface formed between a silane-coated glass fiber and an epoxy matrix. The gradient in the structure of the epoxy resin as a result of the cure process at the fiber/matrix interfacial region was monitored by FTIR imaging. For comparison, the epoxy curing at the interface formed between the epoxy resin and (a) an uncoated glass fiber and (b) a polyorganosiloxane (obtained from the silane used for the glass-fiber coating) were also monitored. Chemically specific images of the OH and the H-N-H groups near the interface region were obtained. These images suggest that there is a chemical gradient in the structure of the matrix from the fiber surface to the polymer bulk due to different conversions. The basis of the different kinetics of the curing reactions is a result of amino group inactivation at the interface. This deactivation translates into an off-stoichiometry of the reaction mixture, which is a function of the distance from the surface of the glass fiber.

Journal Article↗