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PubMedDate not supplied

Flow behavior of erythrocytes in microvessels and glass capillaries: effects of erythrocyte deformation and erythrocyte aggregation.

Flow behavior of erythrocytes in microvessels and glass capillaries with an inner diameter of 10-50 microns was compared in relation to erythrocyte deformation and erythrocyte aggregation. This study was focused on the formation of a marginal cell-free layer, and the thickness was determined using an image processor. Human erythrocytes were perfused through a part of microvascular networks isolated from rabbit mesentery and through glass capillaries. Erythrocyte deformability was modified by treating erythrocytes with diamide, diazene-dicarboxylic acid bis[N,N-dimethylamide], and erythrocyte aggregation was accelerated by adding dextran (with a molecular weight of 70,400) to the perfusion medium. The thickness of the cell-free layer increased with an increase of the inner diameter of flow channel, with lowering the hematocrit, and with increasing the flow velocity of erythrocytes, in both microvessels and glass capillaries. Furthermore, the thickness of cell-free layer decreased with decreasing erythrocyte deformability, while it increased with accelerating erythrocyte aggregation. However, the alteration of the cell-free layer in response to the changes of these hemorheological conditions was more sensitive in microvessels than in glass capillaries. The present study concludes that flow behavior of erythrocytes in microvessels is qualitatively similar to, but quantitatively different from those in glass capillaries, as far as evaluated by the change of the thickness of the marginal cell-free layer.

Animals↗
PubMed1992

Cerebral microcirculatory changes after cerebral embolization induced by glass bead injection in rabbits.

The authors investigated microcirculatory changes in cerebral embolization induced by an injection of glass beads (mesh size 20/400, 15 mg/body) using intravital microscopy and reflectance spectrophotometry in normal rabbits. Cerebral embolization with the glass bead injection reduced the inner diameter of cerebral arterioles, the index of cerebral hemoglobin concentration (IHb), and the index of oxygen saturation (ISO2). Moreover, platelet aggregation rates and plasma levels of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) appreciably increased. During observation of the pial vasculature, "white bodies" became visible at the entrance of arteriolar branchings two to three minutes after the glass bead injection. After indomethacin administration (3 mg/kg, IV), they could not observe white bodies, and platelet aggregation rates were significantly reduced. The plasma levels of TXB2 and 6-keto-PGF1 alpha were also significantly reduced. These findings suggest that glass beads do injury to the microvascular endothelial cells leading to development of white bodies, ie, "flying thrombi." Therefore, the cerebral microvascular embolization induced by the glass bead injection appears to be an experimental model for evaluating efficacy of remedies for the cerebral microcirculatory disorders.

6-Ketoprostaglandin F1 alpha↗
PubMed2006

In vitro cytotoxicity of Manville Code 100 glass fibers: effect of fiber length on human alveolar macrophages.

BACKGROUND: Synthetic vitreous fibers (SVFs) are inorganic noncrystalline materials widely used in residential and industrial settings for insulation, filtration, and reinforcement purposes. SVFs conventionally include three major categories: fibrous glass, rock/slag/stone (mineral) wool, and ceramic fibers. Previous in vitro studies from our laboratory demonstrated length-dependent cytotoxic effects of glass fibers on rat alveolar macrophages which were possibly associated with incomplete phagocytosis of fibers >or= 17 microm in length. The purpose of this study was to examine the influence of fiber length on primary human alveolar macrophages, which are larger in diameter than rat macrophages, using length-classified Manville Code 100 glass fibers (8, 10, 16, and 20 microm). It was hypothesized that complete engulfment of fibers by human alveolar macrophages could decrease fiber cytotoxicity; i.e. shorter fibers that can be completely engulfed might not be as cytotoxic as longer fibers. Human alveolar macrophages, obtained by segmental bronchoalveolar lavage of healthy, non-smoking volunteers, were treated with three different concentrations (determined by fiber number) of the sized fibers in vitro. Cytotoxicity was assessed by monitoring cytosolic lactate dehydrogenase release and loss of function as indicated by a decrease in zymosan-stimulated chemiluminescence. RESULTS: Microscopic analysis indicated that human alveolar macrophages completely engulfed glass fibers of the 20 microm length. All fiber length fractions tested exhibited equal cytotoxicity on a per fiber basis, i.e. increasing lactate dehydrogenase and decreasing chemiluminescence in the same concentration-dependent fashion. CONCLUSION: The data suggest that due to the larger diameter of human alveolar macrophages, compared to rat alveolar macrophages, complete phagocytosis of longer fibers can occur with the human cells. Neither incomplete phagocytosis nor length-dependent toxicity was observed in fiber-exposed human macrophage cultures. In contrast, rat macrophages exhibited both incomplete phagocytosis of long fibers and length-dependent toxicity. The results of the human and rat cell studies suggest that incomplete engulfment may enhance cytotoxicity of fiber glass. However, the possibility should not be ruled out that differences between human versus rat macrophages other than cell diameter could account for differences in fiber effects.

Journal Article↗
PubMed2003

Optical quality micromachining of glass with focused laser-produced metal plasma etching in the atmosphere.

Recent results are reported about the optical quality surface finish obtained on glass substrates with focused laser beam produced metal plasma etching in the atmosphere. The bombardment of high-speed, high-temperature electrons from an underdense plasma on the surface of glass substrates appears to play a dominant role in this process. The effective laser fluence window for this high-quality glass machining on common microscope slides is relatively narrow. With a Corning microslide 2947, and by use of carbon steel as the plasma source, we obtained parameters between 3.5 and 4.5 J/cm2. Above the upper limit, laser-induced optical breakdown occurs in the glass material and leads to the formation of microcracks. Below the lower limit, the process was found to be ineffective. In these experiments highly defined, clean, sharp-edged, 50 x 50 micropit arrays of 15.0-microm diameter with a depth of 3.2 microm and a center-to-center separation of 18.0 microm were fabricated on Corning microslide 2947 glass substrates.

Journal Article↗
PubMed2006

Development of a compression molding process for three-dimensional tailored free-form glass optics.

Because of the limitation of manufacturing capability, free-form glass optics cannot be produced in a large volume using traditional processes such as grinding, lapping, and polishing. Very recently compression molding of glass optics became a viable manufacturing process for the high-volume production of precision glass optical components. An ultraprecision diamond-turning machine retrofitted with a fast tool servo was used to fabricate a free-form optical mold on a nickel-plated surface. A nonuniform rational B-spline trajectory generator was developed to calculate the computer numerical control machine tool path. A specially formulated glass with low transition temperature (Tg) was used, since the nickel alloy mold cannot withstand the high temperatures required for regular optical glasses. We describe the details of this process, from optical surface geometry, mold making, molding experiment, to lens measurement.

Journal Article↗
PubMed2006

Exceptionally narrow homogeneous linewidth in erbium-doped glasses.

We show that rare-earth (RE-) doped glasses can have homogeneous linewidths as narrow as 287 kHz at (4)He temperatures. This is far narrower than others reported in glasses in the same temperature range and is suitable for precise spectral hole burning and spatial-spectral holographic applications. It is known that cw spectral hole burning linewidth measurements of RE ions in glasses are hindered by the presence of spectral diffusion but, even in glasses, application of a magnetic field can freeze out RE spin-spin interactions responsible for spectral diffusion and isolate the remaining contribution of two-level systems (TLSs). The Er(3+):2G2S glasses have unusually low TLS contributions, making it possible to study the real homogeneous linewidth using photon echo measurements. The contribution from TLSs is only 170 T(1.3) kHz when subjected to a field of 5 T.

Journal Article↗
PubMed1988

The effect of nicotine on the attachment of human fibroblasts to glass and human root surfaces in vitro.

This study examined the effect of nicotine on fibroblast attachment to glass and nondiseased human root surfaces. Human foreskin fibroblasts (HFF) were trypsinized, suspended in RPMI 1640 medium, and incubated with autoclaved human root sections and nicotine concentrations of zero (control), 25, 50, 100, 200, or 400 ng/ml. The root sections were examined for fibroblast attachment at 24, 48, and 72 hours by light microscopy and scanning electron microscopy (SEM). Additional trypsinized HFF were incubated on glass surfaces with the same concentrations of nicotine and examined at one week by light microscopy. HFF attached and grew on glass and root surfaces at all concentrations of nicotine. Controls on glass surfaces exhibited a normal monolayer of long spindle-shaped fibroblasts with a parallel alignment and minimal overlapping. Nicotine-treated HFF exhibited a haphazard arrangement with cell overlapping and vacuolization of the cytoplasm. Under SEM, the controls had smooth surfaces and appeared firmly attached to the root surface via (1) microvilli and filopodia on the cell boundaries and (2) short, branched, thin-to-medium width cytoplasmic processes with microvilli and filopodia on their boundaries. Few microvilli were noted on the control cell surfaces. HFF exposed to nicotine had microvilli and filopodia on the cell surfaces and long thin and long broad cytoplasmic processes with many microvilli and filopodia that projected away from the root surface. These findings suggest that the nature of fibroblast attachment to glass and root surfaces is altered by nicotine. A similar disturbance in fibroblast attachment may occur in humans who use nicotine-containing products, making them more susceptible to destruction of the periodontium and less responsive to new attachment after periodontal therapy.

Cell Adhesion↗
PubMed1997

Comparison of porous bone mineral and biologically active glass in critical-sized defects.

Several materials have been proposed as therapies to augment alveolar bone and to promote periodontal regeneration. However, there are an insufficient number of studies that effectively evaluated these therapies. Consequently, the purpose of this study was to compare bone regeneration promoted by porous bone mineral and biologically active glass. Unilateral critical-sized defects (CSDs) were prepared in the radii of 24 rabbits, divided evenly between 2 time periods (4 and 8 weeks) and between 2 treatment groups (porous bone mineral and biologically active glass). Evaluations consisted of clinical examinations, standardized radiography at baseline and every 2 weeks thereafter, as well as histology and histomorphometry. Data were analyzed by an unpaired Student t-test with significance established at P < or = 0.05. We determined that CSDs treated with porous bone mineral were significantly more radiopaque than biologically active glass-treated sites at both 4 and 8 weeks. Moreover, the amount of new bone was significantly greater at both 4 and 8 weeks in the porous bone mineral groups than in the biologically active glass groups. We concluded that in the rabbit radius CSD wound model, porous bone mineral appears to be more effective than biologically active glass in regenerating bone.

Alveolar Bone Loss↗
PubMed1989

[A study on glass-ceramic for dental implant. Histopathological response in animal experiment].

The endosseous dental implants of glass-ceramic were implanted and holes were drilled as control in edentulous areas of adult dog mandibles. The implants were kept without function. After 2-84 days, the biological reaction of the tissue was examined by histological and ultrastructural methods, while the glass-ceramic surface was examined by EPMA analysis and X-ray diffraction. The results were as follows: 1. After 4 days the bone matrix formation started on the surface of the glass-ceramic. After 14 days, the area of bone formation on the implant surface was enlarged and about all surface was covered with this woven bone. 2. Being compared with the control, glass-ceramic didn't prevent the healing process of bone. 3. On the surface of glass-ceramic, apatite and beta-whitlockite crystal formation was observed by X-ray diffraction. And analysis by EPMA showed this areas combined bone. 4. TEM observation showed that there were many hemidesmosomes in interface between the implant and attached epithelium. In the subepithelial fibrous tissue collagen fibers and fibroblasts were arranged in parallel on the implant surface.

Animals↗
PubMed1998

A-W glass ceramic as a bone substitute in cemented hip arthroplasty: 15 hips followed 2-10 years.

We retrospectively reviewed hip arthroplasties in 13 patients (15 hips), in whom we had used apatite-wollastonite (A-W) glass ceramic together with auto- or allograft for augmentation of severe bone deficiency. 11 cemented sockets and 4 stem revisions were included and followed for 2-9.6 years. There were no radiolucent lines between A-W glass ceramic and surrounding bone, and remodeling of the bone graft containing A-W glass ceramic was observed. No migration of cemented sockets was seen except in 1 case, which was revised. In this case, direct bonding between bone and A-W glass ceramic granules was present histologically. In 4 stem revisions, 5 mm subsidence occurred in 1 case. However, the stem became stable and remodeling of the grafted bone occurred. An artificial bone material, such as A-W glass ceramic, can be used under high-load conditions, because of its good mechanical properties.

Adult↗
PubMed1991

[The way for carrying medicines and its containers (VI) "Packaging material--glass bottle"].

Production of glass ware, though it was only used for ornaments, was performed in Japan from ancient times. We can find them in relics of the ancient. But it was only two hundred years ago that glass bottles were applied to medicines. The bottles and a method of making a glass bottle were introduced in the Edo period by studying science in the Dutch language. It instructed us that the glass bottle could be applied to containers for medicines, and that the glass bottle was useful for the containers to protect medicines from light and moisture.

Drug Packaging↗
PubMed2002

Signals in macaque striate cortical neurons that support the perception of glass patterns.

Glass patterns are texture stimuli made by pairing randomly placed dots with partners at specific offsets. The strong percept of global form that arises from the sparse local orientation cues has made these patterns the subject of psychophysical investigations, yet neuronal responses to Glass patterns have not been studied. We measured the responses of neurons in macaque striate cortex (V1) to dynamic, translational Glass patterns as a function of dot separation and dot-pair orientation. Responses were selective, but were on average more than an order of magnitude weaker than responses to sinusoidal gratings. Response and selectivity were greatest when the dot-pair orientation matched that of the preferred grating and when dot separation was between one-quarter and one-half of the spatial period of the optimal grating; changing the dot-pair separation or inverting the contrast of one of the dots radically changed the orientation selectivity. We computed the expected responses for a receptive field model to translational Glass patterns and found that the complexity of our V1 tuning curves could be understood in terms of the responses of linear filters to pairs of dots. This modeling connects our understanding of V1 receptive fields as rectified, quasi-linear filters with results from psychophysical studies of Glass patterns. Our results provide a basis for studying how subsequent visual areas integrate weak, local signals into global form percepts.

Action Potentials↗
PubMed1999

[Construction of Streptococcus mutans surface protein antigen eukaryotic expression vector pcDNA3-PAc. II. Testified efficiency of repeated using glass fiber chromatographic column].

OBJECTIVE: To explore one method getting highly purified plasmid DNA and costing low. METHODS: According to principle of extraction and purification plasmid DNA of glass fiber chromatographic column, its operation sequence was improved so that disposable glass fiber chromatographic column could be used repeatedly. The concentration and purity of plasmid DNA obtained by 12 times repeated using glass fiber chromatographic column were determined by spectrophotometry. Moreover, Those plasmid DNA obtained were tested by restriction enzyme and agarose gel electrophoresis, Ligation in vitro and transformation test. RESULTS: 12 times repeated use of glass fiber chromatographic column made no significant difference to the concentration and purity of obtained plasmid DNA (P < 0.05), and plasmid DNA was completely digested by restriction enzyme. The digested fragments were well ligated together by the action of T4 DNA Ligase in ATP ligating buffer in vitro and ligated DNA was well transformed into E. coli. CONCLUSION: Repeated use glass fiber chromatographic column can obtain a lot of highly purified plasmid DNA and cost is low. Digestion, ligation and transformation of those plasmid DNA are not affected. The results may be significant in molecular cloning and study of gene vaccination.

Antigens, Surface↗
PubMedDate not supplied

Utilization of autogenous bone, bioactive glasses, and calcium phosphate cement in surgical mandibular bone defects in Cebus apella monkeys.

PURPOSE: The purpose of the present study was to evaluate the histologic results of bone cavities that were surgically created in the mandibles of Cebus apella monkeys and filled with autogenous bone, PerioGlas, FillerBone, or Bone Source. MATERIALS AND METHODS: Surgical cavities 5 mm in diameter were prepared through both mandibular cortices in the mandibular angle region. The cavities were randomly filled, and the animals were divided into groups according to the material employed: Group 1 cavities were filled with autogenous corticocancellous bone; group 2 cavities were filled with calcium phosphate cement (BoneSource); and group 3 and group 4 cavities were filled with bioactive glass (FillerBone and PerioGlas, respectively). After 180 days the animals were sacrificed, and specimens were prepared following routine laboratory procedures for hematoxylin/eosin staining and histologic evaluation. RESULTS: The histologic analysis showed that autogenous bone allowed total repair of the bone defects; bioactive glasses (FillerBone and PerioGlas) allowed total repair of the defects with intimate contact of the remaining granules and newly formed bone; and the cavities filled with calcium phosphate cement (BoneSource) were generally filled by connective fibrous tissue, and the material was almost totally resorbed. DISCUSSION: The autogenous bone, FillerBone, and PerioGlas provided results similar to those in the current literature, showing that autogenous bone is the best choice for filling critical-size defects. Synthetic implanted materials demonstrated biocompatibility, but the bio-glasses demonstrated osteoconductive activity that did not occur with calcium phosphate (Bone-Source). CONCLUSION: According to the methodology used in this study, it can be concluded that the utilization of autogenous bone and bioactive glasses permitted the repair of surgically created critical-size defects by newly formed bone; the synthetic implanted materials demonstrated biocompatibility, and the bioactive glasses demonstrated osteoconductive activity. The PerioGlas was mostly resorbed and replaced by bone and the remaining granules were in close contact with bone; the FillerBone showed many granules in contact with the newly formed bone; BoneSource did not permit repair of the critical-size defects, and the defects were generally filled by connective fibrous tissue.

Animals↗
PubMed1999

[Luminescence character of Ce3+ in rare earth borate glasses].

Ce3+ doped rare earth borate glasses (BLBL:Ce3+) were synthesized. The excitation and emission spectra and fluorescence decay curves of BLBL:Ce3+ were measured at room temperature. In BLBL:Ce3+ glasses, Ce3+ emits strong purplish-blue light. The results of analyzing spectra and fluorescence lifetime show that there are two kinds of Ce3+ luminescence centres in this kind of rare earth borate glasses. Ce3+ doped rare-earth glasses is a kind of beneficial supplement for Ce3+ fluorescence glasses system.

English Abstract↗
PubMed2005

[Microstructure and mechanical property of a new IPS-Empress 2 dental glass-ceramic].

OBJECTIVE: To investigate the microstructure and mechanical properties of a new IPS-Empress 2 dental glass-ceramic. METHODS: AFM, SEM and XRD were used to analyze the microstructure and crystal phase of IPS-Empress 2 glass-ceramic. The flexural strength and fracture toughness were tested using 3-point bending method and indentation method respectively. RESULTS: IPS-Empress 2 glass-ceramic mainly consisted of lithium disilicate crystal, lithium phosphate and glass matrix, which formed a continuous interlocking structure. The crystal phases were not changed before and after hot-pressed treatment. AFM showed nucleating agent particles of different sizes distributed on the highly polished ceramic surface. The strength and fracture toughness were 300 MPa and 3.1 MPam(1/2). CONCLUSION: The high strength and fracture toughness of IPS-Empress 2 glass ceramic are attributed to the fine lithium disilicate crystalline, interlocking microstructure and crack deflection.

Aluminum Silicates↗
PubMed2005

Development and evaluation of a standard method for the quantitative determination of elements in float glass samples by LA-ICP-MS.

Forensic analysis of glass samples was performed in different laboratories within the NITE-CRIME (Natural Isotopes and Trace Elements in Criminalistics and Environmental Forensics) European Network, using a variety of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) systems. The main objective of the interlaboratory tests was to cross-validate the different combinations of laser ablation systems with different ICP-MS instruments. A first study using widely available samples, such as the NIST SRM 610 and NIST SRM 612 reference glasses, led to deviations in the determined concentrations for trace elements amongst the laboratories up to 60%. Extensive discussion among the laboratories and the production of new glass reference standards (FGS 1 and FGS 2) established an improved analytical protocol, which was tested on a well-characterized float glass sample (FG 10-1 from the BKA Wiesbaden collection). Subsequently, interlaboratory tests produced improved results for nearly all elements with a deviation of < 10%, demonstrating that LA-ICP-MS can deliver absolute quantitative measurements on major, minor and trace elements in float glass samples for forensic and other purposes.

Journal Article↗
PubMed2006

Stroboscopic vision as a treatment for motion sickness: strobe lighting vs. shutter glasses.

INTRODUCTION: Countermeasures (e.g., drugs, training, etc.) designed to combat the problem of space motion sickness (SMS) have had only limited successes. A possible solution for SMS and terrestrial motion sickness may rest in preventing retinal slip via stroboscopic vision. METHODS: There were 32 subjects who participated in a study to investigate the effect of stroboscopic illumination on motion sickness using either a strobe light or liquid crystal display (LCD) shutter glasses. There were 19 subjects who read text and made +/- 20 degrees head movements in the horizontal plane (yaw) at 0.2 Hz while wearing left-right reversing prisms and exposed to 4-Hz stroboscopic or normal room illumination (control condition). Motion sickness was scored using the Miller and Graybiel scale and subjective self-ratings. In a crossover design, testing was repeated using stroboscopic LCD shutter glasses with an additional 13 subjects and 6 subjects from the first condition. RESULTS: During the experiment with a strobe light, motion sickness scores were significantly lower than in the control condition (chi 0.32 strobe vs. chi 3.79 light = p < 0.003). Results with the LCD shutter glasses corresponded with those when the environment was strobed in an otherwise dark room (chi 1.0 glasses vs. chi 4.1 light = p < 0.001). CONCLUSIONS: Stroboscopic illumination reduced the severity of motion sickness symptoms, and shutter glasses with a flash frequency of 4 Hz are as effective as a strobe light. Stroboscopic illumination appears to be an effective countermeasure where retinal slip is a significant factor in eliciting motion sickness due to either self- or surround-motion.

Adult↗