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PubMed1985

Trace element supplementation of sheep: evaluation of various copper supplements and a soluble glass bullet containing copper, cobalt and selenium.

The effect of 5 different copper supplements on copper status of Merino sheep at pasture was examined. Transient increases in plasma copper concentrations occurred following treatment with copper calcium EDTA, copper sulphate, and glass bullets impregnated with copper, cobalt and selenium, but these increases were not considered to be a reliable indication of changes in liver copper reserves. Sheep receiving the glass bullet or 2.5 g oxidised copper wire particles orally or 50 mg copper as copper calcium EDTA parenterally had liver copper concentrations significantly greater than those of untreated sheep for periods up to 51 weeks. Oral doses of 30 mg copper as copper oxychloride, or 300 mg copper as copper sulphate did not alter the liver copper reserves at any stage. The bodyweight and greasy fleece weights were not significantly altered by any of the copper supplements. Plasma vitamin B12 concentrations in sheep given the glass bullet were increased for about 5 months. Thereafter increased plasma vitamin B12 concentrations were observed in all sheep. Blood selenium concentrations were also high during the experiment thereby preventing the evaluation of the glass bullet as a source of selenium.

Animal Nutritional Physiological Phenomena↗
PubMedDate not supplied

Physical factors determining the utility of radiation safety glasses.

Ten types of lenses were tested for their radiation protection properties in three experimental circumstances: (a) Their good geometry (scatter free) attenuation was determined as a function of HVL in a direct x-ray beam. (b) Their dose reducing properties were determined under simulated clinical fluoroscopic conditions, using both ion chambers and thermoluminescent dosimeters (TLD's) while the lenses, mounted in frames, were worn by a head phantom. The head was oriented in four different directions to simulate clinical conditions in a fluoroscopic room. (c) Their dose reducing properties were measured with TLD's while the glasses were worn by radiologists during clinical fluoroscopic procedures. Although several of the lenses could attenuate a direct x-ray beam several thousand times, none of the glasses offer more than a factor of 8 reduction in eye exposure when the glasses are worn during fluoroscopy. This is attributed to backscatter from the fluoroscopist's head and deficient lateral shielding. Some of the glasses may even be causing an increase in eye exposure when the TV monitor is located 90 degrees or more from the patient.

Eye Protective Devices↗
PubMed2000

Measurements of anisotropic sound propagation in glass wool

The attenuation coefficient and phase velocity of plane sound waves propagating in three perpendicular directions in glass wool were measured in the frequency range 50-10,000 Hz. For glass wool of mass density 14 kg/m3 at the frequency 1,000 Hz, the attenuation constant for propagation perpendicular to the glass wool sheets was 75 dB/m, and for propagation parallel with the sheets 57 dB/m. For mass density 30 kg/m3, the corresponding numbers were 140 and 100 dB/m. The measured values were compared with calculated ones taking into account the movements of the fiber skeleton. The calculations need the elastic moduli, which were measured. For density 14 kg/m3 and deformation perpendicular to the glass wool sheets, the static modulus was 2.0 kPa, and for parallel deformation 120 kPa. The corresponding numbers for mass density 30 kg/m3 were 16 and 390 kPa.

Journal Article↗
PubMed2005

Late Bronze Age glass production at Qantir-Piramesses, Egypt.

It has been uncertain whether the glass produced during the Late Bronze Age (LBA) originated in Egypt or Mesopotamia. Here we present evidence for the production of glass from its raw materials in the eastern Nile Delta during the LBA. Glass was made in workshops that were separate from where the production of objects took place. The initial melting of the raw materials to semi-finished glass was done at temperatures of 900 degrees to 950 degrees C, followed by coloration and ingot production at 1000 degrees to 1100 degrees C.

Journal Article↗
PubMed2000

Three-dimensional direct imaging of structural relaxation near the colloidal glass transition

Confocal microscopy was used to directly observe three-dimensional dynamics of particles in colloidal supercooled fluids and colloidal glasses. The fastest particles moved cooperatively; connected clusters of these mobile particles could be identified; and the cluster size distribution, structure, and dynamics were investigated. The characteristic cluster size grew markedly in the supercooled fluid as the glass transition was approached, in agreement with computer simulations; at the glass transition, however, there was a sudden drop in their size. The clusters of fast-moving particles were largest near the alpha-relaxation time scale for supercooled colloidal fluids, but were also present, albeit with a markedly different nature, at shorter beta-relaxation time scales, in both supercooled fluid and glass colloidal phases.

Journal Article↗
PubMed1995

Using the Potts glass for solving the clustering problem.

We present an application of a Potts glass to the clustering problem. Simulated annealing in the mean field approximation is used in order to avoid local minima. The resulting updating equations are completely parallel, and very easy to implement. The model has no free parameters except for the annealing parameters. We show how the model can be implemented for some special clustering problems. The T-->0 limit of the Potts glass is identical to the vector quantization algorithm with certain increments. A comparative study of the Potts glass and vector quantization is also made, and it is shown that for difficult clustering problems, the Potts glass is far better than vector quantization.

Algorithms↗
PubMed1992

Fibrosing alveolitis: prognostic implication of ground-glass attenuation at high-resolution CT.

To evaluate the prognostic implication of ground-glass attenuation at high-resolution computed tomography (HRCT) in assessing response to treatment in fibrosing alveolitis, the authors correlated HRCT findings with the improvement in pulmonary function, as represented by the increase in percentage predicted values on pulmonary function tests after corticosteroid therapy. Nineteen patients underwent HRCT before treatment and pulmonary function testing before and after treatment. The HRCT scans were reviewed by two independent observers. Areas of ground-glass attenuation were quantified subjectively by using a 0%-100% scale with 10% increments. The extent of ground-glass attenuation at HRCT was significantly correlated with improvement in diffusing capacity for carbon monoxide (r = .67, P = .0019), forced vital capacity (r = .71, P = .0007), and forced expiratory volume in 1 second (r = .64, P = .0034) after steroid treatment. These results suggest that ground-glass attenuation at HRCT is a good predictor of response to treatment in fibrosing alveolitis.

Adrenal Cortex Hormones↗
PubMed2005

Covalent attachment of the plant natural product naringenin to small glass and ceramic beads.

BACKGROUND: Natural products have numerous medicinal applications and play important roles in the biology of the organisms that accumulate them. Few methods are currently available for identifying proteins that bind to small molecules, therefore the discovery of cellular targets for natural products with pharmacological activity continues to pose a significant challenge in drug validation. Similarly, the identification of enzymes that participate in the biosynthesis or modification of natural products remains a formidable bottleneck for metabolic engineering. Flavonoids are one large group of natural products with a diverse number of functions in plants and in human health. The coupling of flavonoids to small ceramic and glass beads provides a first step in the development of high-throughput, solid-support base approaches to screen complex libraries to identify proteins that bind natural products. RESULTS: The utilization of small glass and ceramic beads as solid supports for the coupling of small molecules was explored. Initial characterization of the beads indicated uniform and high capacity loading of amino groups. Once the beads were deemed adequate for the linking of small molecules by the coupling of NHS-fluorescein followed by microscopy, chemical hydrolysis and fluorometry, the flavonoid naringenin was modified with 1,4-dibromobutane, followed by the attachment of aminopropyltriethoxysilane. After NMR structural confirmation, the resulting 7-(4-(3-(triethoxysilyl)propylamino)butoxy) naringenin was attached to the ceramic beads. CONCLUSION: Our results demonstrate that ceramic and glass beads provide convenient solid supports for the efficient and facile coupling of small molecules. We succeeded in generating naringenin-coupled ceramic and glass beads. We also developed a convenient series of steps that can be applied for the solid-support coupling of other related flavonoids. The availability of solid-support coupled naringenin opens up new opportunities for the identification of flavonoid-binding proteins.

Journal Article↗
PubMedDate not supplied

Effects of distraction using virtual reality glasses during lumbar punctures in adolescents with cancer.

PURPOSE/OBJECTIVES: To determine the effects of virtual reality (VR) glasses on adolescents with cancer undergoing lumbar punctures (LPs). DESIGN: Pilot study using an experimental, control group design. SETTING: In-hospital oncology clinic. SAMPLE: 30 adolescents with cancer (17 in the VR and 13 in the control group) undergoing frequent LPs. METHODS: Subjects were randomly assigned to groups. Both groups received standard intervention during the LP, but the experimental group also wore VR glasses and watched a video. Following the LP, both groups rated their pain using a visual analog scale (VAS) and were interviewed to evaluate their experience. MAIN RESEARCH VARIABLES: Pain, subjective evaluation of experience. FINDINGS: Although VAS pain scores were not statistically different between the two groups (p = 0.77), VAS scores tended to be lower in the VR group (median VAS of 7.0, range 0-48) than in the control group (median VAS of 9.0, range 0-59). 77% of subjects in the experimental group said the VR glasses helped to distract them from the LP. CONCLUSIONS: VR glasses are a feasible, age-appropriate, nonpharmacologic adjunct to conventional care in managing the pain associated with LPs in adolescents. IMPLICATIONS FOR PRACTICE: The clinical application of various age-appropriate distracters to reduce pain in adolescents undergoing painful procedures should be explored.

Adolescent↗
PubMed2000

Can a two-glass urine test or leucocyte esterase test of first-void urine improve syndromic management of male urethritis in southern Thailand?

The goal of this study was to determine whether a urine two-glass test or a leucocyte esterase (LE) test of first-void urine (FVU) improve the sensitivity or specificity of the World Health Organization (WHO) algorithm for the syndromic management of men with urethritis in southern Thailand. A secondary aim was to determine whether infection with Trichomonas vaginalis was sufficiently common to include treatment for it in a syndromic management protocol. One hundred and twenty-nine men with symptoms of urethritis seen at 2 STD clinics in Songkla Province, Thailand were enrolled. Symptoms and signs of each man were recorded and a urethral swab collected for microscopy and culture for Neisseria gonorrhoeae. A two-glass urine test and an LE test of an FVU specimen were performed. The FVU was tested by polymerase chain reaction (PCR) for N. gonorrhoeae, Chlamydia trachomatis and T. vaginalis. Dysuria was a symptom in 78% of men. A urethral discharge was a symptom in 68% but was evident on examination in 95% of the men. The prevalences of infection were 32.6% for N. gonorrhoeae, 23.3% for C. trachomatis, 1.6% for T. vaginalis and 51.9% for any infection. The sensitivities and specificities of urethral discharge on examination, two-glass test and LE test of FVU as indicators of infection with either or both of N. gonorrhoeae or C. trachomatis were 97% and 8%; 57% and 83%; and 59% and 78% respectively. Combinations of urethral discharge on examination and one of the other indicators were more specific but much less sensitive than the presence of discharge alone. Culture for N. gonorrhoeae was found to be only 43% sensitive compared with an expanded gold standard involving a PCR test. Our analysis demonstrates that neither the two-glass test nor the LE test of FVU were useful in improving on the WHO algorithm for management of men with urethritis. T. vaginalis was not common enough to include in a first-line syndromic management protocol for male urethritis. We recommend that, in southern Thailand, men with symptoms of urethritis in whom a urethral discharge is present on examination be offered immediate treatment for both N. gonorrhoeae and C. trachomatis as per the WHO algorithm.

Animals↗
PubMed2002

Refractive-index changes caused by proton radiation in silicate optical glasses.

We have studied experimentally, by using a differential interferometric technique, the effect of proton radiation on the refractive index of commercial (Schott) silicate crown glasses, BK7 and LaK9, and their radiation-resistant counterparts. The strongest effect was observed for the radiation-hard lanthanum crown LaK9G15: At a 0.65-Mrad dose the index change was approximately 3 x 10(-5). Radiation-hard glasses are used in optical systems operating in radiation environments because they prevent spectral transmission degradation in the visible. However, such glasses are not protected against radiation-induced refractive-index perturbations, and a diffraction-limited optical system based on such glasses may fail owing to radiation-induced aberrations.

Journal Article↗
PubMed2002

Dispersion of barium gallogermanate glass.

Gallogermanate glasses are the subject of intense study as a result of their unique combination of physical and optical properties, including transmission from 0.4 to beyond 5.0 microm. These glasses can be easily made into large optics with high-index homogeneity for numerous U.S. Department of Defense and commercial visible-IR window applications such as reconnaissance, missile domes, IR countermeasures, avionics, and collision avoidance on automobiles. These applications require a knowledge of the refractive index of glass throughout the region of transmission. Consequently, we have measured the refractive index of BaO-Ga2O3-GeO2 glass from 0.4 to 5.0 microm and calculated the Sellmeier coefficients required for optical device design.

Journal Article↗
PubMed2003

Thermal forming of glass microsheets for x-ray telescope mirror segments.

We describe a technology to mass-produce ultrathin mirror substrates for x-ray telescopes of near Wolter-I geometry. Thermal glass forming is a low-cost method to produce high-throughput, spaceborne x-ray mirrors for the 0.1-200-keV energy band. These substrates can provide the collecting area envisioned for future x-ray observatories. The glass microsheets are shaped into mirror segments at high temperature by use of a guiding mandrel, without polishing. We determine the physical properties and mechanisms that elucidate the formation process and that are crucial to improve surface quality. We develop a viscodynamic model for the glass strain as the forming proceeds to find the conditions for repeatability. Thermal forming preserves the x-ray reflectance and scattering properties of the raw glass. The imaging resolution is driven by a large wavelength figure. We discuss the sources of figure errors, and we calculate the relaxation time of surface ripples.

Journal Article↗
PubMed2003

Colloidal gold submonolayer-coated thin-film glass plates for waveguide-coupled surface plasmon resonance sensors.

A novel optical sensor based on spectroscopic measurement of the plasmon absorption of a colloidal gold submonolayer immobilized upon a planar waveguide has been developed for label-free detection of biomolecular interactions at the sensor's surface. We fabricated the sensor by locally modifying a 50-microm-thick glass plate with hemoglobin (Hb) and then self-assembling gold colloids from the aqueous solution onto the Hb-modified area of the glass plate. Polychromatic light from a xenon-arc lamp was launched into the thin-film glass plate by use of a broadband fiber-coupling method. With the use of a CCD detector to monitor the light beam emitted from an end face of the glass plate, the plasmon absorption spectrum of the colloidal gold submonolayer was determined to depend on the polarization states of the guided light and to change with the refractive index of the medium in contact with the colloids. In addition to simplicity of fabrication and the ease of use, the sensor yields a larger absorbance sensitivity than the normal transmission measurement.

Journal Article↗
PubMed2003

High-speed two-dimensional laser scanner based on Bragg gratings stored in photothermorefractive glass.

A high-speed free-space wavelength-multiplexed optical scanner with high-speed wavelength selection coupled with narrowband volume Bragg gratings stored in photothermorefractive (PTR) glass is reported. The proposed scanner with no moving parts has a modular design with a wide angular scan range, accurate beam pointing, low scanner insertion loss, and two-dimensional beam scan capabilities. We present a complete analysis and design procedure for storing multiple tilted Bragg-grating structures in a single PTR glass volume (for normal incidence) in an optimal fashion. Because the scanner design is modular, many PTR glass volumes (each having multiple tilted Bragg-grating structures) can be stacked together, providing an efficient throughput with operations in both the visible and the infrared (IR) regions. A proof-of-concept experimental study is conducted with four Bragg gratings in independent PTR glass plates, and both visible and IR region scanner operations are demonstrated.

Journal Article↗
PubMed2003

Effect of tin diffusion on the optical behavior of float glass in the soft-x-ray region.

The optical responses of two sides of float glass in the soft-x-ray region were studied at the Indus-1 synchrotron facility. To the best of our knowledge these are the first experimentally obtained optical data for both sides of float glass in the soft-x-ray region. Optical constants delta and beta were determined by use of angle-dependent reflectance techniques in the wavelength range 80-200 A. On the side of the glass that was tin indiffused, a significant difference in delta value from that of the non-tin-side surface was observed. The measured data were compared with Henke's tabulated value of SiO2. The surface roughness of float glass was separately determined by hard-x-ray reflectivity to minimize the number of fitting variables. The effect of a contamination layer on the determination of optical constants was avoided by an appropriate sample-cleaning method.

Journal Article↗
PubMed2005

Precision compression molding of glass microlenses and microlens arrays--an experimental study.

An innovative manufacturing process utilizing high-temperature compression molding to fabricate aspherical microlenses by using optical glasses, such as BK7, K-PG325, and soda-lime glass, is investigated. In a departure from conventional approaches, a unique hollow contactless mold design is adopted. Polished glass substrates and the mold assembly are heated above the glass transition temperature first, followed by initial forming, then annealing. The forming rate is controlled in real time to ensure mold position accuracy. Mold materials used include tungsten carbides, 316 stainless steel, 715 copper nickel, and aluminum alloys. The geometric control of the microlenses or microlens arrays can be precisely controlled by the forming temperature, forming speed, mold design, and annealing time.

Journal Article↗
PubMed2004

Optical properties of structurally modified glasses doped with gold ions.

We report on the optical properties of a structurally modified silicate glass doped with Au ions. The area in the vicinity of the focal point of an 800-nm femtosecond laser in a glass sample became gray as a result of the formation of color centers after laser irradiation and turned red because of precipitation of Au nanoparticles after further annealing at 550 degrees C for 30 min. When the glass was excited by UV light at 365 nm, yellowish-white and orange-yellow emissions were observed in the laser-irradiated and the Au-nanoparticle-precipitated area, respectively. An optical Kerr shutter experiment showed that the Au nanoparticle-precipitated glass had an ultrafast nonlinear optical response, and the third-order nonlinear susceptibility was estimated to be approximately 10(-11) esu.

Journal Article↗

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