PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Microscopy, Ultraviolet”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 361 records · Page 20Linked to original sources
PubMed1995

An immunofluorescence assay in microwell plate (IFA) for detecting serum antibodies to Chlamydia pneumoniae.

An indirect immunofluorescence assay using a 96 microwell cell culture plate (IFA) was developed for the detection of antibodies to C. pneumoniae. The results obtained by IFA on 230 sera of healthy subjects were compared with those obtained with the microimmunofluorescence test. The correlation coefficient for IgG detection with the two methods was 0.96 showing good agreement.

Adult↗
PubMed1994

Sodium fluoride sustained-release bone cement: an experimental study in vitro and in vivo.

A new "low temperature" bone cement, consisting of polymethylmethacrylate (PMMA) and 6% sodium fluoride, was developed for use in orthopedics. Fluoride is a well-known agent that may stimulate osteoblast activity and differentiation in vitro and in vivo; for this reason fluoride has been used for 30 years in the treatment of osteoporotic diseases of the bone. A local effect obtained with a slow release of fluoride from bone cement at the interface between bone and prosthetic implants could potentially enhance new bone formation around the prosthesis. This material was investigated both "in vitro", by establishing the kinetics of fluoride release from the acrylic bone cement and its maximal compressive strength, and "in vivo", by fitting 24 rabbits, which were then killed after 4, 12 and 16 weeks, with femoral implants, following labelling with fluorescent stains to allow the histologic evaluation of bone remodelling. The "in vitro" study revealed the release kinetics of fluoride from bone cement and the compressive strength of PMMA, that is not affected by the addition of fluoride. The "in vivo" investigation showed considerable healing ability after surgical and heat trauma, and new bone formation that appears larger on the surface in contact with fluoridated cement.

Animals↗
PubMed1993

Excitation-induced Ca2+ dynamics in sympathetic neurons measured with conventional epifluorescence and confocal UV laser-scanning microscopes.

A depolarization-induced rise in intracellular Ca2+ in cultured bullfrog sympathetic ganglion cells depended non-linearly on Ca2+ influx and membrane depolarization, spread inwardly faster than that without Ca(2+)-induced Ca2+ release (CICR), and was blocked by dantrolene and ryanodine. Ca2+ entry and a graded activation of CICR thus induce the "Ca2+ transient."

Animals↗
PubMed1993

[Chemical and traumatic irritation of a canine premolar tooth germ].

The arrest of a premolar bud was observed in an animal experiment that was designed to study the influence of endodontic treatment in dogs' temporary teeth on the eruption of their permanent successors. A chemical irritation was induced by the burst of ZOE (zinc oxide and eugenol) into the dental follicle. Moreover, a mechanical trauma on the temporary molar was promoted by the dog's biting on its cage metallic bars. The devitalization effects were studied in thick undecalcified ground sections which were subjected to microradiographic analysis, to UV light microscopy in order to detect the fluorescent indicators of calcification, and finally to methylene blue staining. The arrest of the bud development was noted in fluorescent microscopic examination. Cellular cementum was formed on the pulpal surface of the dentine, while cementum, chondroid tissue, woven bone and lamellar bone developed in the pulpal tissue. These observations advise caution during root canal therapy of temporary teeth, especially those that are exposed to mechanical trauma. Such as the upper incisors.

Animals↗
PubMed1995

Telemicroscopy stations for telepathology based on broadband and ISDN connections.

Telemicroscopy equipment is a key tool to perform Telepathology successfully. It allows the local separation of the microscope with the tissue samples from the investigating pathologist. The Telemicroscopy stations presented provide the user with a full access to the functions such as scanning stage, focus, illumination and magnification selection of a remote microscope. One system applies as communication link a broadband video conference net of the German Telekom with full realtime capabilities and color TV-image quality. As this network provides adequate interfaces for video and computer net signals, it is well suited to establish within a short time interval a very comfortable Telemicroscopy connection without the development of additional equipment. As the broadband network is expensive the application is economically restricted to special applications. The other system relies on the narrow band connections of the ISDN telephone network. This design is inexpensive with respect to data transmission and is available nearly worldwide everywhere. But on the other hand this strategy is limited concerning realtime capabilities. To reduce these limitations to an acceptable level intelligent coding and operation concepts of the stations have to be developed.

Computer Communication Networks↗
PubMed1991

Changes in polyphosphate composition and localization in Propionibacterium acnes after near-ultraviolet irradiation.

Electron microscopy showed that electron-dense granules accumulated in Propionibacterium acnes in larger amounts when the bacteria were grown on a phosphate-rich medium. X-ray microanalysis demonstrated that the granules contained mostly phosphorus and potassium, indicating that the cells contained polyphosphate granules. When cells were grown on a complex Bacto-agar medium, the amount and the size of the polyphosphate granules were reduced. Polyphosphate was also detected with 31P nuclear magnetic resonance (31P-NMR). Of the polyphosphates observed with 31P-NMR, 20% seemed to be located outside the cell membrane. Broad-band near-ultraviolet irradiation (emission maximum 366 nm) corresponding to doses that killed 37% of the cells increased the amount of polyphosphate in cells grown on the phosphate-rich medium. The fluorescent chromophore 4',6-diamidino-2-phenylindole (DAPI) shifted the fluorescence emission from 478 to 538 nm when bound to polyphosphate and excited at 340 nm. DAPI was used to detect polyphosphates generated after near-ultraviolet irradiation of the cells. Nonirradiated cells showed no increased fluorescence at 538 nm, indicating no polyphosphate is presented in the cells. We conclude that DAPI did not have "access" to the intracellular polyphosphate as long as the cells were not light damaged. This observation is important for the interpretation of near-UV damage to cells.

Centrifugation, Density Gradient↗
PubMed2001

Scanning tunneling microscopy, orbital-mediated tunneling spectroscopy, and ultraviolet photoelectron spectroscopy of metal(II) tetraphenylporphyrins deposited from vapor.

Thin films of vapor-deposited Ni(II) and Co(II) complexes of tetraphenylporphyrin (NiTPP and CoTPP) were studied supported on gold and embedded in Al-Al(2)O(3)-MTPP-Pb tunnel diodes, where M = Ni or Co. Thin films deposited onto polycrystalline gold were analyzed by ultraviolet photoelectron spectroscopy (UPS) using He I radiation. Scanning tunneling microscopy (STM) and orbital-mediated tunneling spectroscopy (STM-OMTS) were performed on submonolayer films of CoTPP and NiTPP supported on Au(111). Inelastic electron tunneling spectroscopy (IETS) and OMTS were measured in conventional tunnel diode structures. The highest occupied pi molecular orbital of the porphyrin ring was seen in both STM-OMTS and UPS at about 6.4 eV below the vacuum level. The lowest unoccupied pi molecular orbital of the porphyrin ring was observed by STM-OMTS and by IETS-OMTS to be located near 3.4 eV below the vacuum level. The OMTS spectra of CoTPP had a band near 5.2 eV (below the vacuum level) that was attributed to transient oxidation of the central Co(II) ion. That is, it is due to electron OMT via the half-filled d(z)(2) orbital present in Co(II) of CoTPP. The NiTPP OMTS spectra show no such band, consistent with the known difficulty of oxidation of the Ni(II) ion. The STM-based OMTS allowed these two porphyrin complexes to be easily distinguished. The present work is the first report of the observation of STM-OMTS, tunnel junction OMTS, and UPS of the same compounds. Scanning tunneling microscope-based orbital-mediated tunneling provides more information than UPS or tunnel junction-based OMTS and does so with molecular-scale resolution.

Journal Article↗
PubMed1971

Microorganisms in unamended soil as observed by various forms of microscopy and staining.

A light-diffraction microscope was modified to allow sequential viewing of the microorganisms in a soil smear by transmitted, reflected, and reflected-polarized incandescent light and by reflected ultraviolet light. Observations were also made by conventional incandescent and ultraviolet transmitted-light microscopy. All results for the various forms of bright-field microscopy with stained and unstained soils were in agreement, but they differed from the results obtained for two types of ultraviolet-fluorescence microscopy. The latter proved to be nonspecific for in situ soil microorganisms. Capsule-like areas were noted surrounding many of the resident microbial cells of soil when viewed by the various forms of bright-field microscopy. These areas could not be stained or removed by a variety of treatments, but they apparently often did take up stain after in situ soil growth had been initiated. It was concluded that these areas are not capsules but may represent a structural component of nonmultiplying microbial cells in soil.

Acridines↗
PubMed2006

Polymer-coated magnetic nanoparticles: surface modification and end-functionalization.

ATRP (atom transfer radical polymerization) approach was employed to synthesis polymer-coated magnetite nanoparticles. These particles had an average diameter of 7.1 nm and a narrow size distribution. Characterization was performed using various techniques like Transmission Electron Microscopy (TEM), Ultraviolet-Visible spectroscopy (UV-vis), Fourier Transform Infrared spectroscopy (FTIR), Atomic Force Microscopy (AFM), and Vibrating Sample Magnetometry (VSM). The challenge was to obtain a thin shell and discrete particles in an unagglomerated state. Several factors like presence/choice of solvent, monomer-to-initiator concentration and structure of initiator were found to play a key role in this study. Attempts have been made to tailor the polymer shells by end-functionalization. This work has an enormous biomedical application potential.

Crystallization↗
PubMed2005

Effects of a central metal on the organization of 5,10,15,20-tetra-(p-chlorophenyl)-rare earth porphyrin hydroxyl compound at the air/water interface and in Langmuir-Blodgett films.

Langmuir monolayers and Langmuir-Blodgett (LB) films of 5,10,15,20-tetra-(p-chlorophenyl) terbium/gadolinium porphyrin hydroxyl compound (TbOH and GdOH) and their mixtures with stearic acid (SA) in a molar ratio of 1:1 were investigated by Brewster angle microscopy (BAM), ultraviolet-visible (UV-vis), and infrared (IR) spectroscopy and atomic force microscopy (AFM). pi-A isotherms showed that well-defined Langmuir monolayers were formed at an air/water interface for the porphyrins and their mixture with SA. The BAM observations suggest that the pi-pi interaction between the GdOH molecules is stronger than that between the TbOH molecules. This result can be further confirmed by the AFM measurements. After the introduction of SA, the pi-pi interaction between the TbOH molecules is broken and thus two phases formed in the mixed LB film. However, it cannot break the stronger pi-pi interaction between the GdOH molecules. Therefore, no phase separation is observed in the GdOH/SA LB film. IR reflection-absorption (RA) spectra showed that the COOH groups of SA are partly converted to COO(-) groups, suggesting that there is an interaction between MOH and SA in the films. This interaction leads the benzene rings of TbOH to rotate toward parallel to the substrate and those of GdOH to rotate toward perpendicular to the substrate. All these results have demonstrated that the central metal ions have great effects on the organization and formation of the films.

Journal Article↗
PubMedDate not supplied

Applications of free-electron lasers in the biological and material sciences.

Free-Electron Lasers (FELs) collectively operate from the terahertz through the ultraviolet range and via intracavity Compton backscattering into the X-ray and gamma-ray regimes. FELs are continuously tunable and can provide optical powers, pulse structures and polarizations that are not matched by conventional lasers. Representative research in the biological and biomedical sciences and condensed matter and material research are described to illustrate the breadth and impact of FEL applications. These include terahertz dynamics in materials far from equilibrium, infrared nonlinear vibrational spectroscopy to investigate dynamical processes in condensed-phase systems, infrared resonant-enhanced multiphoton ionization for gas-phase spectroscopy and spectrometry, infrared matrix-assisted laser-desorption-ionization and infrared matrix-assisted pulsed laser evaporation for analysis and processing of organic materials, human neurosurgery and ophthalmic surgery using a medical infrared FEL and ultraviolet photoemission electron microscopy for nanoscale characterization of materials and nanoscale phenomena. The ongoing development of ultraviolet and X-ray FELs are discussed in terms of future opportunities for applications research.

Biology↗
PubMed2000

In vivo diffuse damage in human vertebral trabecular bone.

Accumulation of microdamage in vivo may lead to loss of bone quality. Until recently, linear microcracks were the only known form of in vivo microdamage, but through the use of confocal microscopy an additional level of damage (diffuse damage) has been identified. In this study, in vivo diffuse damage was characterized and quantified in human vertebral trabecular bone as a function of tissue morphology, age, race, gender, and previously quantified in vivo linear microcracks. Presence of diffuse damage in human vertebral tissue was confirmed and validated by simultaneous use of polarized, ultraviolet, and laser confocal microscopy. Diffuse damage was found to occur preferentially within trabecular packets rather than in interstitial bone (p < 0.05). It was consistently higher in men compared with women (p < 0.05), but was not different by race or age group. Diffuse damage did not correlate with linear microcracks, but both exhibited the same probability distribution in which the percentage of individuals having a particular amount of damage decreased exponentially as damage content increased. These findings suggest that diffuse damage accumulation and repair are governed by the same biological phenomena as microcracks, but diffuse damage contributes independently to the microdamage content of bone.

Adult↗