[New intensifying films in roentgen diagnosis. A clinically oriented evaluation of rare earth films in comparison to conventional films].
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Humans↗
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Evaluating sol-gel ceramic thin films for metal implant applications. I. Processing and structure of zirconia films on Ti-6AI-4V.
Thin ceramic films or coatings over metallic bone-interfacing implant surfaces have the potential to improve implant performance with respect to implant fixation, wear, or corrosion. In this study, zirconia (ZrO2) thin films formed on Ti-6AI-4V using a polymeric alkoxide-based solgel process were investigated. ZrO2 films of uniform thickness on the order of 100 nm were obtained by dip coating Ti-6AI-4V samples into a zirconium propoxide containing solution using a substrate withdrawal speed ranging from 2 to 8 cm/min and a sol of nominal viscosity approximately 6 cps. These films were essentially free of surface macrodefects but had random submicron "pinholes." X-ray diffraction studies suggested that the films were at least partially crystalline, with some "metastable" cubic and/or tetragonal phases after annealing for 1 h at 500 degrees C. The demonstrated reproducibility of this approach for producing good quality ZrO2 films on Ti-6AI-4V warrants further studies to optimize processing conditions for implant applications.
Alloys↗
Thin films of Ag nanoparticles prepared from the reduction of AgI nanoparticles in self-assembled films.
A novel method for the preparation of thin films of Ag nanoparticles is reported. Using mercaptoacetic acid as the stabilizing agent, AgI nanoparticles were prepared in aqueous solution. And based on electrostatic interactions, the thiol-passivated AgI nanoparticles were assembled in a self-assembled film by alternative deposition with a cationic polyelectrolyte. Then the AgI nanoparticles in the composite film were reduced by NaBH(4), which resulted in the formation of a thin film of Ag nanoparticles. UV-visible spectra and X-ray photoelectron spectroscopy data confirmed the transformation from AgI to Ag. Atomic force microscopy (AFM) showed that the formed Ag nanoparticles distributed on the film homogeneously. Surface-enhanced Raman spectroscopy (SERS) measurement indicated that the prepared thin films could be used as effective SERS substrates. The reduction process was also carried out by UV light at selective surface regions, which resulted in the formation of patterned nanoparticle arrays.
Journal Article↗
The role of synovial fluid filtration by cartilage in lubrication of synovial joints--IV. Squeeze-film lubrication: the central film thickness for normal and inflammatory synovial fluids for axial symmetry under high loading conditions.
The axially symmetric problem of synovial film filtration and synovial gel formation at normal approach of cartilage surfaces in the human hip joint loaded by a compressive force has been solved numerically in Part III of this paper [Hlavácek and Novák, J. Biomechanics 28, 1193-1198 (1995)] for the Newtonian viscous phase of the biphasic synovial fluid and for low loads only. Because of a high non-linearity of the problem the method used there breaks down for higher loads. On anticipating that for a high step loading the fluid pressure in the central part of the squeezed synovial film is close to the pressure in a dry frictionless contact, the synovial film filtration at the film centre is governed by two ordinary differential equations that are easy to solve. The central gel film thickness thus obtained, i.e. the film thickness at the moment, when the filtered fluid turns into a stable gel is about 1 micron for the normal synovial fluid (with a non-Newtonian viscous phase of the synovial fluid) and changes very little if the geometric, material and loading parameters of the problem vary within the physiological range. The inflammatory case (with a more or less Newtonian viscous phase) yields values by one order lower at least. The results of stress analysis in the cartilage for this mixture model suggest the reason for vertical cracking at the free cartilage surface and horizontal splitting at the tide mark observed in osteoarthritic joints.
Biomechanical Phenomena↗
Arabinoxylan-lipid-based edible films and coatings. 3. Influence of drying temperature on film structure and functional properties.
This work is a contribution to better knowledge of the influence of the structure of films obtained from emulsions based on arabinoxylans, hydrogenated palm kernel oil, and emulsifiers on their functional properties. The sucrose esters (emulsifiers) have a great effect on the stabilization of the emulsified film structure containing arabinoxylans and hydrogenated palm kernel oil. The structure and stability of the emulsion during drying strongly affect barrier and mechanical properties of films. The higher are creaming and coalescence phenomena in films, the lower is the water vapor permeability. Emulsion destabilization is favored by high drying temperature and tends to give films having a "bilayer-like" structure, which tends to improve the functional properties of arabinoxylans-based edible films.
Chemical Phenomena↗
Adhesion of particulate specimens to support films for electron microscopy: a model system for assessing the surface properties of support films, and its application to chromatin particles.
Silica microspheres bearing a known surface charge were used to test the adhesive properties of support films and support film treatments commonly used in the electron microscopy of particulate specimens. Adhesion was strongly correlated with surface charge, negatively charged microspheres binding well only to positively charged support films and vice versa in solutions of low ionic strength. This charge dependency could be overcome by increasing the ionic strength to about 100 mmol with monovalent cations; under these conditions, it was not necessary to provide an oppositely charged film surface to obtain adhesion. Chromatin particles (nucleosomes) which have a net negative charge, behaved very much like the negatively charged silica with respect to adhesion, confirming that the microspheres provided an accurate indication of support film surface properties. The chromatin particles showed dramatic structural changes under conditions when adhesion was either poor, or very strong, indicating the need for careful selection of binding conditions for delicate biological specimens. A new and simple method for pretreating carbon films to improve adhesion was developed, and a preliminary account of this technique is presented.
Carbon↗
Phantom evaluation of the effect of film processing on mammographic screen-film combinations.
Mammographic image quality should be optimal for diagnosis, and the film contrast can be manipulated by altering development parameters. In this study phantom test objects were radiographed and processed for a given range of developer temperatures and times for four film-screen systems. Radiologists scored the phantom test objects on the resultant films to evaluate the effect on diagnosis of varying image contrast. While for three film-screen systems processing led to appreciable contrast differences, for only one film system did maximum contrast correspond with optimal phantom test object scoring. The inability to show an effect on diagnosis in all cases is possibly due to the variation in radiologist responses found in this study and in normal clinical circumstances. Other technical factors such as changes in film fog, grain and mottle may contribute to the study findings.
Mammography↗
Theory of elastic wave propagation in anisotropic film on anisotropic substrate: TiN film on single-crystal Si.
The delta-function representation of the elastodynamic Green's function is used to derive an expression for the elastic wave forms on the surface of an anisotropic thin film on an anisotropic substrate due to a point or a line source located at the surface of the film. The dispersion relation for surface acoustic waves (SAWs) is obtained from the poles of the Green's function. A computationally efficient algorithm is formulated to obtain the elastic constants and the density of the film from the SAW dispersion data. The theory is used to analyze measured SAW dispersion relations in a titanium nitride film on silicon. The analysis yields values of the elastic constants and the density of the film. Excellent agreement is obtained between the theoretical and experimental dispersion results. Calculated wave forms for the surface wave due to a pulsed line source on the surface of the film are reported.
Journal Article↗
[Photoluminescence from Er-doped silicon-rich silicon oxide film and Er-doped silicon-rich silicon nitride film and its annealing behavior].
Room temperature photoluminescence (PL) with a peak at 1.54 microns was observed from silicon oxide, silicon-rich silicon oxide, silicon nitride and silicon-rich silicon nitride films, all doped with Er and grown by the magnetron sputtering technique. To determine the optimum annealing temperature for the 1.54 microns PL, these films were annealed in the range of 600-1,100 degrees C with an interval of 100 degrees C. Among these four types of films annealed at an identical temperature, the intensity of 1.54 microns PL peak of the Er-doped silicon-rich silicon oxide film was always the strongest one, which arrived at a maximum in 800 degrees C annealing. A 1.38 microns PL band was also observed in each of these four types of films, and which in the silicon-rich silicon oxide or silicon-rich silicon nitride films was found to be correlated with the 1.54 microns PL band in intensity.
Chemical Phenomena↗
An evaluation of Ektaspeed Plus film versus Ultraspeed film for endodontic working length determination.
Thirteen teeth in human cadaver sections were accessed and #15 K-files were placed at various lengths in one root canal of each tooth. Using a positioner to ensure duplicate views, radiographs were taken with both Ultraspeed and Ektaspeed Plus X-ray film. Each of the 26 radiographs was coded and then placed in random order. Six endodontic specialists measured the distance from the file tip to the radiographic apex on each film. The results were analyzed by analysis of variance and Cronbach's generalizability theory. It was found that 94% of the variance in measurements was due to differences among the viewers, whereas 5% was due to a combination of viewers and tooth. Only 1% was due to differences between the two types of film. It was concluded that Ektaspeed Plus film may be used for working length radiographs because it requires only approximately 50% of the radiation needed for Ultraspeed film.
Analysis of Variance↗
Clinical assessment of dry laser-processed film versus traditional wet-processed film with computed tomography, magnetic resonance imaging, and ultrasound.
RATIONALE AND OBJECTIVES: To compare image quality and diagnostic performance (by using receiver operating characteristic techniques) for laser imaging film from two systems: a traditional wet system that uses chemical processing and a new dry system that is wet-chemistry-free. METHODS: For three separate studies (computed tomography, magnetic resonance imaging, and ultrasound), identical images for 40 cases were printed on both the wet and dry imaging systems. Ten radiologists participated in each study, giving a decision confidence rating for lesion present or absent and evaluating image quality. RESULTS: In all three studies, there were no statistically significant differences in diagnostic performance when reading images that had been wet processed versus those that had been dry processed. Image quality was comparable for wet-and dry-processed films for all three modalities. CONCLUSION: Dry laser processing produces high-quality radiologic films that are comparable to those currently produced by using wet laser processing. Dry-processed film represents a useful alternative to wet-processed film.
Lasers↗
A comparison of two different T-grain films in rare-earth screens with a standard film-screen combination for intravenous pyelography and bone examinations.
T-grain film is claimed to give significantly improved image quality, allowing the use of faster screens without loss of quality and thus reducing radiation dose. We tested this claim for two systems. In each case comparison was made with our usual screen-film combination, Agfa Curix RP1 film with Kodak Xomatic Regular screens (a nominally 200 speed system). The systems tested were Kodak TMatG in Kodak Lanex Medium screens (300 speed) and Agfa STG in Kodak Lanex Regular screens (400 speed). The Agfa STG-Lanex Regular system performed less well than the standard system for intravenous pyelograms (IVPs), bones and soft-tissue detail. Its speed advantage was not apparent below 70 kV. The Kodak TMatG-Lanex Medium system was better than the standard system for IVPs but not as good for bones. It gave virtually no speed advantage below 90 kV. Kodak T-grain film in a medium-speed, rare-earth screen was found to be better than the standard system for IVPs. Agfa T-grain film in a fast rare-earth screen was unsatisfactory for IVPs. Neither combination was as good as the standard system for bones.
Bone and Bones↗
Comparison of an asymmetric screen-film combination with a conventional screen-film combination for chest radiography in 51 patients.
Comparison is made between a new asymmetric screen-film combination and a conventional screen-film combination for use in chest radiography. Seven anatomical features were assessed by three consultant radiologists in each of 51 film pairs. A preference was indicated if one system better demonstrated a particular feature. Alternatively, no preference was indicated if the feature was equally demonstrated by both systems or not demonstrated at all. Any pathology incidentally noted which remained unchanged between the two films was localized to lung, mediastinum or bone and marked in the same way. The asymmetric high contrast system scored higher than the conventional system for demonstration of anatomy in both mediastinum and lungs, but no difference emerged between the two systems in the demonstration of pathology. The asymmetric screen-film system showed improved mediastinal and, to a lesser degree, improved lung detail. Further assessment in necessary to define any associated improvement in diagnostic yield.
Decision Making↗
[Importance of blackening of films and conditions of assessment of films for diagnostic decision of X-rays of teeth, the tooth supporting apparatus and adjacent structures of the jaw].
The influence of blackening of films and conditions of assessment of films for diagnostic decisions had been examined. Various pictures of the Periodontitis apikalis chronica at x-ray pictures had been chosen the subject of examination. It should be ascertained by means of the ROS concept to what extent variations of the above-mentioned parameters will result in false diagnoses. The most favourable result is gained with film blackening of 1.2 SE and a lightness of the film equipment of 12,000 Lx. A reduced lightness of the equipment will reduce the quality of diagnostics in essential manner. Optimum conditions for evaluation of the film are given for pictures over- and under-exposed.
Humans↗
Objective and subjective assessments of Kodak Ektaspeed plus new dental X-ray film: a comparison with other conventional X-ray films.
A new dental X-ray film called EKTASPEED Plus has been released by the Eastman Kodak Company. Its sensitometric properties, inclusive of modulation transfer function (MTF) and Wiener spectrum (WS) and the visibility of radiographic details, were compared with those of other conventional dental X-ray films, EKTASPEED EP-22 (Eastman Kodak Co.) and Ultra-Speed DF-57 (Eastman Kodak Co.). The base plus fog density of EKTASPEED Plus was between those for EKTASPEED and Ultra-Speed. Relative speed of EKTASPEED Plus was slightly faster than EKTASPEED, and about two times faster than that of Ultra-Speed. The contrast of EKTASPEED plus was close to that of Ultra-Speed. Only minor differences existed between the film types studied when the sharpness and the granularity were compared. The MTF and WS also revealed no substantial differences between the films. Perceptibility testing showed minor differences between the three films, with EKTASPEED Plus consistently revealing more defects at lower exposures irrespective of whether a Burger's phantom or aluminum test block was used.
Evaluation Studies as Topic↗
Influence of time and exposure to air on radiographic contrast and relative film speed of three rapid dental film processing solutions.
The aim of this study was to determine the influence of exposure to air and time on the radiographic contrast and relative film speed of three processing solutions. A modified aluminium step-wedge phantom was used to expose varying numbers of Kodak Ektaspeed films daily for periods up to 57 days. The radiographic contrast and relative film speed were determined each day using a digital densitometer. Data obtained were analysed statistically, using Duncan's Multiple Range Test, and a 3-Factor ANOVA. It was found that, for radiographic contrast, Insta-Neg gave the highest values, followed by Kolchem and Ultra-Neg. For relative film speed, Kolchem gave the highest values, followed by Insta-Neg and Ultra-Neg. Both radiographic contrast and relative film speed decreased with the passage of time. Processing solutions kept in closed containers continued to perform efficiently for a longer time than those in open containers. The useful period was found to exceed that which is usually recommended.
Air↗
Small-angle X-ray scattering studies of fibrin film: comparisons of fine and coarse films prepared with thrombin and ancrod.
Measurements of small-angle x-ray scattering have been made on films prepared from fine and coarse (i.e., formed at high and low, respectively, pH and ionic strength) clots of bovine fibrin by osmotic shrinkage or compression in one dimension. Intensity profiles were obtained with pinhole geometry on films stretched up to a stretch ratio of 1.43. In unstretched coarse films, repeat spacings were seen at about 245, 120, and 77-80 A. These peaks can probably be identified with the first, second, and third orders of the well-known fibrin repeat of 225 A. In unstretched fine films, only the 77-80 A spacing was seen. In this case, the first two orders may be weak because the half-staggered arrangement of monomer units giving rise to the 225 A reflection is not reinforced by lateral aggregation of protofibrils; the third order may be strong since the molecular subdomains appear to divide the repeat roughly into thirds. After stretching, the 77-80 A spacing persisted in the meridional direction but almost disappeared in the equatorial. Experiments on unstretched films prepared with ancrod substituted for thrombin gave similar results.
Ancrod↗
Lipid mono- and bilayer supported on polymer films: composite polymer-lipid films on solid substrates.
We report the deposition of lipid monolayers and bilayers on polyacrylamide films deposited by radical chain reaction onto solid substrates in aqueous solutions. Polymer films of various degrees of monomer density and cross-linking are prepared. Lateral diffusion and fluorescent probe permeation measurements yield insight into the continuity of the lipid layers and show that monolayers exposed to air are much less sensitive towards polymer heterogeneities than bilayers below water, which is explained in terms of the wetting laws. The diffusion studies of lipid and lipopeptide probes yield absolute values of the frictional coefficients between the lipid layer and the polymer films and allow one to estimate the surface viscosity of the polymer film. The potential applications of supported membranes on soft thin polymer films for the preparation of biofunctionalized surfaces or biocompatible receptive surfaces for biosensors are discussed.
Acrylic Resins↗