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PubMed1997

Variability in cytotoxicity and fluoride release of resin-modified glass-ionomer cements.

New-generation glass-ionomer cements contain resin to improve their restorative properties. These resin-modified glass-ionomer cements vary considerably in their chemistry, which could result in corresponding variability in their physical and biological properties. This study investigated the cytotoxicity and the fluoride release of two resin-modified glass ionomers, a conventional glass-ionomer cement, and a resin composite. Samples were prepared and extracted in distilled water for 1, 4, and 7 days; eluates were filtered and tested by means of 3T3 mouse fibroblasts. Cytotoxicity (MTT assay) values were low for all materials and extraction times, indicating minimal cytotoxicity of all materials (less than 30% inhibition). Cytotoxicity of one resin-modified glass ionomer was significantly higher than for the other materials (p < 0.001). One resin-modified glass ionomer and the conventional glass-ionomer cement released significantly more fluoride at each time interval (p < 0.001) than the other resin-modified glass-ionomer cement and the resin composite. Fluoride release and cytotoxicity were correlated (r2 = 0.60; p < 0.001), although the fluoride release does not account for the cytotoxicity observed. Cytotoxicity and fluoride release suggest that one hybrid behaved more like a conventional glass ionomer, and the other like a resin composite. These differences may have implications for material selection in specific clinical situations.

3T3 Cells↗
PubMed1984

Effect of cell-substrate interaction time and shearing force on adhesion of L1210 cells to collagen and glass.

The early adhesive interaction of living cells with substrates was examined. L1210 cells were allowed to interact with collagen or glass in serum-containing medium (time of cell-substrate interaction, tint, under stationary conditions, was within 2-25 min) or in serum-free medium (tint was 5 s-15 min). The relative number A of cells adhering under stationary conditions, and remaining adherent to the substrate despite experiencing a shearing force F, was determined. The following was found for cells adherent to collagen and glass, both in the presence and absence of serum in the medium. The number A increases with the value of tint and tends to reach a plateau. The plateau value depends on adhesion conditions (presence or absence of serum). When adhesion occurred in serum-containing medium (F congruent to 0.1 X 10(-13)N), function A(tint) increased up to 15 min. The plateau values were in the ratio of 2:1 for cells adherent to collagen and glass, respectively. When adhesion took place in serum-free medium, the function A(tint) increased within the first 20 or 130s for cells adhering to glass or collagen, respectively. The value of A(tint) increased up to the effective interaction time, teff int, i.e. the time after which a plateau was reached at 100% adhesion. This meant that after tint greater than or equal to teff int all cells were in adhesion with glass and collagen despite the application of the greatest shearing force, F congruent to 2 X 10(-9)N. The values of teff int for cells adherent to collagen and glass were in the ratio of 6:1, respectively. The value of A decreases with the value of F for cells adherent to substrate in the absence of serum when tint less than teff int. The function A(F) for cells adherent to collagen and glass in the presence of serum, but not in the absence of serum, can be described by the equation: A = a/square root F + c, where a and c = constant greater than 0. The values of a were in the ratio of 2:1 for cells adherent to collagen and glass, respectively. The Brownian motion of cells interacting with both substrates in the absence of serum ceased. The times during which cell motion persisted for cells interacting with collagen and glass, respectively, were in the ratio of 2.5:1.

Animals↗
PubMed1996

Bioactive glass granules and plates in the reconstruction of defects of the facial bones.

Non-vascularised bone grafts that are used for reconstruction of skeletal deformities of the face after trauma or tumour surgery are prone to resorption. The outcome may, therefore, not be what was expected. Bone was reconstructed with bioactive glass S53P4 granules and plates at 36 sites in 13 patients. The behaviour of the material was compared with that of bone grafts at 16 sites in the same patients. Bioactive glass granules were used in facial bone defects in subperiosteal pockets and to obliterate frontal sinuses, whereas bioactive glass plates were used mostly in orbital wall reconstruction. Clinical examination, middle face radiographs, and computed tomograms (CT) showed that the material was well tolerated. A third of the glass granules and a quarter of the membranous bone grafts that were fixed with miniplates retained their original size. The glass plates did not change in size. Bone contact to the host bone was found more often with the bioactive glass plates than with the bioactive glass granules or the bone grafts. Both the glass plates and the bone grafts retained their density, but there was a reduction in density of the glass granules. The clinical outcome showed no relapses after one year's follow up. No further operations were needed because of the material used.

Adolescent↗
PubMed1997

Influence of modification of Na2O in a glass matrix on the strength of leucite-containing porcelains.

The desirable thermal properties of matrix glass to the strength of feldspar porcelain with leucite crystal were investigated. Five kinds of feldspar glasses, each with different a content of Na2O, were prepared for the matrix glasses of the leucite-containing porcelains. The specimens were arranged by mixing each glass powder with high-purity natural leucite crystals (0, 20 and 40%) followed by firing. The thermal properties of the glass and the transformation temperature of the leucite were measured. A three-point bending test was performed to measure the flexural strength of the porcelains. The glass transition temperature and deformation temperature of the glass-only porcelains were decreased as the Na2O content increased. The Na2O-modified glasses were substantially strengthened by the leucite dispersion. However, the strength of the porcelains was affected by the relation between the transformation temperature of the leucite and the thermal properties of the glass matrix. It was concluded that control of the residual stress in the composite porcelain is an important factor in developing high strength porcelain containing leucite.

Aluminum Silicates↗
PubMed2006

[Comparison of glass particle contamination according to method of ampule cutting and needle aspiration].

PURPOSE: Glass particle contamination of the contents of single-dose glass ampules can occur upon opening. Different aspiration techniques, different sizes of needles, different sizes of ampules, and different cutting methods were studied to determine if they had any effect on glass particle contamination. METHOD: Different aspiration techniques(with filter, without filter), different sizes of needles(18G, 25G), different sizes of ampules(2 ml, 20 ml), and different cutting methods (with cotton, without cotton) were evaluated. METHOD: Twenty ampules were randomly assigned in each group. Three slides containing glass particles for each ampule were made and counted under a microscope by 3 study blind persons. RESULT: The number of glass particle contamination is much less when using a filter rather than without a filter. The number of glass particle contamination is much less when using a 25G needle rather than on 18G needle. The number of glass particle contamination is much less when using 2 ml ampules rather than 20 ml ampules. The number of glass particle contamination is much less when using cotton rather than without cotton. CONCLUSION: It was shown that using a filter, a small size needle, smaller sized ampules and using cotton when cutting the ampule will decrease the risk of parenteral injection of glass particles.

Drug Contamination↗
PubMed2004

Glass-fiber frameworks for fixed partial dentures: laser-interferometrical in vitro analysis.

OBJECTIVES: Laboratory tests confirmed superior physical properties of fiber-reinforced resin composites; however, clinical failures continue to be observed. This in vitro study introduces a new method to measure strain and fracture resistance in glass fiber-reinforced pontics. METHOD AND MATERIALS: Thirty standardized pontics in five groups were fabricated. Pontics were reinforced with: glass fiber (group 1); glass-fiber bundle surrounded by glass-fiber mesh (group 2); glass fiber with glass-fiber mesh parallel to the pontic's occlusal surface (group 3); or glass-fiber mesh parallel to glass-fiber bundle (group 4). Unreinforced resin composite pontics served as controls (group 5). A laser interferometer measured inner strains (microm/mm) in sectioned pontics, occlusally loaded with 250 N and 450 N, with a universal testing machine. Inner strains were measured on three levels (1, 2, and 3). Specimens were then loaded to crack onset, and loads were recorded. Comparisons were made using analysis of variance. Kruskal-Wallis and Fisher's exact tests were used, respectively, for nonparametric and categorical data. RESULTS: Group 3 showed significantly lower mean strain values than controls. No significant differences in maximal inner strain values or crack onset loads were recorded. The framework of Group 3 inhibited crack propagation significantly better than that in groups 2 and 5. CONCLUSION: Within the limitations of this study, speckle interferometry proved to be a promising method for analyzing strains of pontics under load. The tested framework designs in this study had only limited influence on load-to-crack onset. When strategically placed, a glass-fiber mesh prevented crack propagation.

Analysis of Variance↗
PubMed1981

Stability and compatibility of antitumor agents in glass and plastic containers.

The stability of methotrexate, fluorouracil, cytarabine, dactinomycin, doxorubicin, bleomycin sulfate, mitomycin, mithramycin, vincristine sulfate, vinblastine sulfate, cyclophosphamide, dacarbazine, carmustine, and leucovorin calcium in underfilled plastic and glass administration containers was determined. Drugs were reconstituted according to manufacturers' instructions and added to 5% dextrose injection 50 ml in both polyvinyl chloride bags and glass partial-fill bottles. In addition, mitomycin was added to 0.9% sodium chloride injection 50 ml in both polyvinyl chloride bags and glass partial-fill bottles. All admixtures were stored at room temperature, not protected from light. Stability was determined over 24 hours (48 hours for doxorubicin and fluorouracil) by high-pressure liquid chromatography, except for cyclophosphamide (analyzed by mass spectrometry) and carmustine (analyzed by spectrophotometry). Methotrexate, leucovorin calcium, cytarabine, dactinomycin, mithramycin, vinblastine sulfate, cyclophosphamide, and dacarbazine were equally stable (10% or less change in concentration over 24 hours) in glass and plastic containers. Doxorubicin and fluorouracil were more stable in plastic containers than glass containers. The T90 value for doxorubicin in glass was 40 hours; there was no apparent decrease in plastic even after 48 hours. The T90 value for fluorouracil in glass was seven hours and in plastic, 43 hours. Vincristine sulfate, bleomycin sulfate, and carmustine were more stable in glass than plastic. The T90 value for vincristine sulfate in plastic was 10 hours. The T90 value for bleomycin sulfate in plastic was 0.7 hour. The T90 value for carmustine in plastic was 0.6 hour. Mitomycin dissolved in 0.9% sodium chloride injection was more stable in plastic. Mitomycin dissolved in 5% dextrose injection was not stable. Carmustine and bleomycin sulfate should be administered only in glass containers. Continuous infusions of doxorubicin and fluorouracil are more completely delivered from plastic containers. Mitomycin should not be dissolved in 5% dextrose injection.

Antineoplastic Agents↗
PubMedDate not supplied

Fracture toughness ov conventional or photopolymerized glass ionomer/dentin interfaces.

Several new light-cured glass-ionomer materials have been developed for restorative use. It is not yet clear, however, whether the ability of the conventional glass ionomers to bond chemically to dentin has been preserved in the new light-cured glass ionomers whose chemical compositions have been modified. The fracture toughness test was recently introduced as an appropriate method of measuring the fracture resistance of an interface. We have applied this test to the glass ionomer/dentin interface for the first time. Ten mini short-rod fracture-toughness specimens were fabricated for each group. Each specimen contained a chevron-shaped glass ionomer/dentin interface along its midplane. After 24 hours in 37 degrees C water, the specimens were tested by loading at 0.5 mm/min. The interfacial Kic results (MPa X m (1/2)) (SD), analyzed by ANOVA and Fisher's LSD test (P<0.05), were: Chem-fil II, 0.17 (0.04); Vitremer, 0.18 (0.15); Fuji II LC, 0.33 (0.16). There were no significant differences in interfacial Kic between the conventional and light-cured glass ionomers. Interfacial Kic's for a light-cured glass ionomer were, however, significantly higher when an intermediary dentin bonding agent was used. SEM examinations of the fractured surfaces indicated that crack propagation generally occurred along the bond interface, and indicated the formation of a resin-infiltrated layer when the dentin bonding agents were used. It was concluded that the fracture-toughness test could be a useful measure of the integrity of the glass ionomer/dentin interface. The clinical effect of an intermediary layer between the glass ionomer and the tooth structure is, however, unknown and requires further investigation.

Aluminum Silicates↗
PubMed1976

[Transfixion of cervical cord by a glass fragment--report of a case (author's transl)].

Stab wound of the spinal cord caused by accident occurred in the home life is rare absolutely. One case of stab wound of the cervical spinal cord caused by penetrated and retained glass fragment within the spinal canal was reported. A 30-year-old woman was hospitarized on August 16, 1971. with complaint of left hemiparesis, gait disturbance and sensory impairment on the right side. A glass door fell down on the patient's neck on April 14, 1971. and one glass fragment was removed from the patient's left neck by one of the patient's family and no immediate spinal cord symptom appeared and no physician was consulted at that time. One and a half month after the injury the patient rod a motor bicycle and pain and severe stiffness in the shoulder and neck, and headache. These subjective symptom disappeared by rest and same subjective symptom repeated in following five days. Three and a half months after the injury the patient found sensation loss in the right foot and gait distrubance appeared. After the sensory impairment extended to the cervical level which was accompanied by left hemiparesis. On examination, the patient was found to have merked weakness of left limbs, spastic gait and severe impairment of touchpain- and thermosensation below the fifth cervical level but deep sensation was preserved. All tendon reflexes showed marked exaggeration and pathological reflexes were proved. Roentgenograms of the cervical spine revealed a long triangular glass fragment which had been retained in the spinal canal between the first and second cervical vertebrae. The air myelogram suggested the glass fragment had transfixed the cervical spinal cord. Laminectomy was performed and the glass fragment which had a shape of a sharp pointed surgical knife was removed by gentle move in the opposite direction of invation. Following removal of the foreign body, the patient's left hemiparesis recovered to normal state at four months after the operation and right sensory impairment also improved. The cervical spinal cord may be injured in the following way: the right lateral spinothalamic tract may be injured by the skewer injury due to glass fragment but injury of the left same tract may be avoided because of oblique direction of penetration of the glass fragment in the spinal cord. On the other hand, the left pyramidal tract may be compressed by glass fragment and not injured, because left hemiparesis recovered very well postoperatively.

Accidents, Home↗
PubMed2007

A calorimetric investigation of thermodynamic and molecular mobility contributions to the physical stability of two pharmaceutical glasses.

The purpose of this work was to investigate the contribution of thermodynamics and mobility to the physical stability of two pharmaceutical glasses with similar glass transition temperatures (Tg), by comparing configurational thermodynamic quantities and molecular relaxation time constants (tau) at temperatures below Tg. Ritonavir and nifedipine were chosen as model glasses because they show excellent and poor physical stability, respectively. Although ritonavir and nifedipine have similar Tg values (50 and 46 degrees C, respectively), amorphous ritonavir is quite stable while nifedipine has been reported to crystallize at temperatures as low as 40 degrees C below Tg. Modulated temperature differential scanning calorimetry (MTDSC) was used to characterize both crystalline phases and freshly prepared glasses. The glasses were then annealed at Tg-Ta = 25 degrees C while monitoring the extent of relaxation and heat capacity change as a function of time via MTDSC. Configurational thermodynamic quantities (Gc, Hc, and Sc) and molecular relaxation time constants, tau, were calculated from the calorimetric data. Interestingly, the Gibbs free energy driving force for crystallization was nearly identical for the two compounds. The largest differences were found in the configurational entropy (Sc) values for the fresh glasses and in the Sc values over time. Configurational entropy values were approximately 50% higher for ritonavir. The tau values of freshly prepared glasses indicated that both materials had similar initial mobility at the annealing temperatures and the temperature dependence of tau was approximately Arrhenius, regardless of age. Although initial tau values were similar, the tau values after 3 days annealing were approximately sixfold greater for ritonavir. The relatively poor physical stability of nifedipine compared to ritonavir is attributed to both the lower entropic barrier to crystallization for fresh and annealed glass, and higher molecular mobility in aged glasses of nifedipine. These observations below Tg are consistent with the previous work on physical stability of amorphous pharmaceuticals performed above Tg.

Calorimetry, Differential Scanning↗
PubMed2006

Effect of ZnO addition on bioactive CaO-SiO2-P2O5-CaF2 glass-ceramics containing apatite and wollastonite.

Some ceramics show bone-bonding ability, i.e. bioactivity. Apatite formation on ceramics is an essential condition to bring about direct bonding to living bone when implanted into bony defects. A controlled surface reaction of the ceramic is an important factor governing the bioactivity and biodegradation of the implanted ceramic. Among bioactive ceramics, glass-ceramic A-W containing apatite and wollastonite shows high bioactivity, as well as high mechanical strength. In this study, glass-ceramics containing zinc oxide were prepared by modification of the composition of the glass-ceramic A-W. Zinc oxide was selected to control the reactivity of the glass-ceramics since zinc is a trace element that shows stimulatory effects on bone formation. Glass-ceramics were prepared by heat treatment of glasses with the general composition: xZnOx(57.0-x)CaOx35.4SiO(2)x7.2P(2)O(5)x0.4CaF(2) (where x=0-14.2mol.%). Addition of ZnO increased the chemical durability of the glass-ceramics, resulting in a decrease in the rate of apatite formation in a simulated body fluid. On the other hand, the release of zinc from the glass-ceramics increased with increasing ZnO content. Addition of ZnO may provide bioactive CaO-SiO(2)-P(2)O(5)-CaF(2) glass-ceramics with the capacity for appropriate biodegradation, as well as enhancement of bone formation.

Apatites↗
PubMed2005

The nucleation and crystallization of fine grained leucite glass-ceramics for dental applications.

OBJECTIVES: The aims of the study were to control the nucleation and crystal growth of selected aluminosilicate glass powders, to produce uniform leucite glass-ceramic microstructures consisting of fine (<1000 nm) grained leucite crystals. METHODS: A starting glass composition of wt%; 64.2% SiO(2), 16.1% Al(2)O(3), 10.9% K(2)O, 4.3% Na(2)O, 1.7% CaO, 0.5% LiO(2) and 0.4% TiO(2) was heated in an electric furnace and later quenched to produce glasses. The glass powders were ball milled to two different particle sizes and heat-treated using one and two-step crystallization heat treatments. Dta, Xrd, and Sem analyses was used to characterise and explore the crystallization kinetics of the glasses. RESULTS: Selected heat treatments of the glass powders produced a uniform distribution of fine tetragonal leucite crystals (mean+/-S.D.) 0.1+/-0.2 microm(2) in the glassy matrix, with minimal matrix microcraking in the glass-ceramics produced. The addition of a two-step heat treatment increased the leucite volume fraction in all instances. SIGNIFICANCE: Selected crystallization heat treatments and powder particle sizes were used to control the leucite crystal size, distribution and volume fraction, in order to produce uniformly distributed ultra fine grained tetragonal leucite glass-ceramics for dental applications.

Aluminum Silicates↗
PubMed2005

Objective radiologic analysis of ground-glass opacity aimed at curative limited resection for small peripheral non-small cell lung cancer.

OBJECTIVE: The aim of this study was to evaluate the efficacy of the objective radiologic analysis of high-resolution computed tomographic images of small peripheral non-small cell lung cancer and to select the candidates for curative limited resection. METHODS: High-resolution computed tomographic images of 146 surgically resected T1 N0 M0 peripheral non-small cell lung cancers were analyzed by using National Institutes of Health image software and classified on the basis of the percentage of ground-glass opacity within the tumor. RESULTS: Eighty-seven percent of tumors with ground-glass opacity ratios of 90% to 100% (type I) were diagnosed as noninvasive bronchioloalveolar carcinoma, whereas 55.6% of tumors with ground-glass opacity ratios of 50% to 89% (type II) consisted of adenocarcinoma. Tumors with ground-glass opacity ratios of 50% or more (type I/II) had no nodal involvement, whereas nodal metastases were identified in 20.0% of tumors with ground-glass opacity ratios of 10% to 49% (type III) and 24.4% of tumors with ground-glass opacity ratios of less than 10% (type IV). No tumors with ground-glass opacity ratios of 50% or more showed vessel infiltration, except for one lesion with a ground-glass opacity ratio of 50%. The 3-year disease-free survival was 97.7% for type I/II, 86.1% for type III, and 78.5% for type IV tumors. CONCLUSIONS: The objective quantitative radiologic analysis with National Institutes of Health image software exhibited a good correlation with the histologic classification, pathologic invasiveness, and postoperative outcome of small peripheral lung cancer. Patients with tumors that have ground-glass opacity ratios of greater than 50% are considered to be possible candidates for limited pulmonary resection.

Aged↗
PubMed2006

The role of luminance contrast in the detection of global structure in static and dynamic, same- and opposite-polarity, Glass patterns.

Perception of global structure conveyed in static Glass patterns is difficult, though not impossible, when the constituent dipoles are formed by partnering opposite polarity dots. We investigate whether the addition of motion signals to opposite-polarity Glass patterns can act to restore the perception of global structure. The stimuli were concentric Glass patterns consisting of 200 dipoles concentrically orientated, or oriented at random orientations, placed on a grey background. For each dipole, one luminance-increment dot (Weber contrast of 1) was paired with another dot set to a contrast ranging between luminance increment and luminance decrement (i.e., a Weber contrast range of approximately -1 to 1). Dipoles were either stationary (Experiment 1), or randomly re-positioned at 17Hz (Experiment 2), on each frame transition. A two-interval forced-choice paradigm, in conjunction with an adaptive staircase, was used to obtain Glass-pattern detection thresholds. The task required observers to identify the interval that contained concentric Glass structure; the other interval contained randomly orientated dipoles. Generally, lower global form thresholds were observed for dynamic and same-polarity Glass patterns than for static and opposite-polarity Glass patterns. In particular, for dynamic presentations improvement in sensitivity was more evident for opposite-polarity than for same-polarity Glass patterns. These findings suggest that motion plays an important role in the detection of global structure in dynamic Glass patterns.

Contrast Sensitivity↗
PubMed2003

Heat-pressed ionomer glass-ceramics. Part I: an investigation of flow and microstructure.

OBJECTIVES: This study investigated a series of ionomer glasses based on the formula: 4.5SiO(2)-1.5P(2)O(5-)(X)Al(2)O(3)-4.5CaO-0.5CaF(2), where X was varied from 3.0 to 1.5. The possibility of processing ionomer glasses using a heat-pressing method for dental restorations was investigated. METHODS: A simple flow test was designed to measure the amount of flow the glasses underwent as a result of heat-pressing at 1150 degrees C for different times. Heat-pressed samples of the X=3.0, 2.8, 2.4 and 2.0 glass were further heat-treated for 1 and 4 h at 1150, 1200 and 1250 degrees C to promote crystal growth. Scanning electron microscopy was used to investigate the microstructure of the glass-ceramics. X-ray diffraction was used to identify the crystalline phases in the glass-ceramics. RESULTS: The ionomer glasses exhibited excellent flow ability. Crystallization could not be suppressed during heat-pressing. Very fine scale fluorapatite crystals were present in all of the samples after heat-pressing. Mullite and/or anorthite formed as a second crystal phase. On further heat-treatment of the samples, changes in crystal phases took place. SIGNIFICANCE: Apatite was the main crystalline phase produced in the glass-ceramics; this factor is of clinical significance. In conclusion these glass-ceramics could be suitable for all-ceramic dental restorations.

Acrylic Resins↗
PubMed2004

Elastic constants, Vickers hardness, and fracture toughness of fluorrichterite-based glass-ceramics.

OBJECTIVES: To determine the elastic constants, Vickers hardness, and indentation fracture toughness of fluorrichterite glass-ceramics in the system SiO2-MgO-CaO-Na2O-K2O-F. METHODS: Five glass compositions were prepared with increasing sodium content. The compositions were melted at 1400 degrees C for 2 h and cast into 60 x 12 mm rods. Discs (1.5 x 12 mm) were cut from the glass rods, nucleated in the temperature range 600-650 degrees C for 1 h and crystallized at 900 degrees C for 0.5 h. The density of the glass-ceramics was measured by Archimedes' method. The elastic constants were determined by standard ultrasonic velocity technique. The fracture toughness was evaluated by the indentation technique. The indentation crack patterns and microstructure were investigated by scanning electron microscopy. The crystalline phases were identified by X-ray diffraction. A commercially available lithium disilicate glass-ceramic served as control. RESULTS: The fluorrichterite glass-ceramics containing 3.8 and 5.6 wt% sodium had the lowest mean fracture toughness. The glass ceramic containing 1.9 wt% sodium and the control material had the highest mean fracture toughness. The values obtained for these two materials (2.26 +/- 0.15 MPa m0.5 and 2.29 +/- 0.31 MPa m0.5, respectively), were not significantly different (p = 0.997). There was no linear relationship between the amount of sodium present in the glass-ceramic composition and the mean fracture toughness. The fluorrichterite glass ceramics exhibited a dual microstructure consisting of both fluorrichterite and mica crystals. SIGNIFICANCE: Higher fracture toughness appeared to be associated with a higher density of fluorrichterite crystals.

Analysis of Variance↗
PubMed2001

SoI--gel modification of pH electrode glass membranes for sensing anions and metal ions.

To obtain glass membrane electrodes selective for anions and metal ions, pH electrode glass membranes were modified by a sol-gel method using a quaternary ammonium salt and a bis(crown ether). A chloride ion-sensing glass membrane was designed, in which a pH electrode glass membrane was modified chemically by an alkoxysilyl quaternary ammonium chloride. X-ray photoelectron spectroscopy confirmed the chemical bonding of the quaternary ammonium moiety to the starting glass surface, which afforded the first example of glass-based "anion"-sensing membranes. A neutral carrier-type sodium ion-selective glass membrane was also fabricated which encapsulates a bis(12-crown-4) derivative in its sol-gel-derived surface. Both sol-gel-modified anion and metal ion-selective glass electrodes exhibited high sensitivity to their ion activity changes. The present sol-gel modification paves the way for designing glass-based ion sensors with tailor-made ion selectivities toward anions as well as cations.

Journal Article↗
PubMed2006

Preparation process and upconversion luminescence of Er3+-Doped glass ceramics containing Ba2LaF7 nanocrystals.

The preparation process and upconversion luminescence of the Er(3+)-doped glass ceramics containing Ba(2)LaF(7) nanocrystals were investigated. The formation of Ba(2)LaF(7) nanocrystals in the glass ceramics was confirmed by X-ray diffraction. Er(3+)-doped glass ceramics containing Ba(2)LaF(7) nanocrystals exhibited highly efficient upconversion luminescence in comparison with glasses. With the increase of heat treatment temperature the upconversion luminescence intensity increased gradually. The composition of glasses was also found to have significant influence on the crystallization process of glass ceramics. The mixture of Ba(2)LaF(7) and La(2)O(3) nanocrystals and the mixture of La(2)F(3) and La(2)O(3) nanocrystals in the glass ceramics could be obtained by controlling different compositions of glasses. The upconversion luminescence intensity also varied significantly with different nanocrystals in the glass ceramics.

Journal Article↗