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At least 127 records · Page 7Linked to original sources
PubMed1989

[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↗
PubMed1995

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↗
PubMed1993

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↗
PubMed1989

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↗
PubMed2005

Effect of interface modification on forces in foam films and wetting films.

The paper reviews the effect of the surface composition on forces within aqueous foam and wetting films. In both types of films the charge of the air/water interface is varied by different surfactants. In wetting films the charge and the hydrophobicity of the solid substrate is changed by polymer coatings. The addition of polymers to foam films leads to the formation of surface active polymer/surfactant complexes or to depletion near the interfaces. The dissolution of polyelectrolytes within the film bulk can lead to structural forces. The selection of studies is made with respect to two questions: (1) What is the reason for charges at the air/water interface and (2) what is the mechanism of long-range hydrophobic interaction?

Biophysics↗
PubMed2004

Fourier transform surface-enhanced Raman scattering of single-layer nucleolipid Langmuir-Blodgett films on silver island film substrates.

Surface-enhanced Raman scattering (SERS) spectra of four amphiphilic nucleolipids in single-layer Langmuir-Blodgett (LB) films deposited on silver island film substrates from pure water and complementary nucleotide-containing subphase and corresponding powder normal Raman spectra were obtained. The analysis of these spectra indicates that the SERS effect is mainly caused by a charge-transfer mechanism, and only the nucleobase headgroup moieties and complementary bases combined with them through hydrogen bonds, which are directly in contact with the silver island film substrates, could be enhanced. For the amphiphilic nucleolipids with the identical nucleobase headgroups, the SERS spectra of the LB films are similar, implying that the orientations of these nucleobase moieties on the silver substrates are analogous. However, the nucleobase takes different orientations on the silver substrates before and after complementary binding. The nucleobases in the LB films deposited from pure water are nearly lying flat on the silver surface, while the complementary binding pairs transferred from the air/water interface tend to take an end-on orientation on the metal surface.

Biocompatible Materials↗
PubMed2005

Film formation from monodisperse acrylic lattices 2. Influence of drying temperature on the film formation process.

The influence of drying temperature on the properties of latex films was investigated by gravimetry, turbidimetry (i.e., analysis of transmission spectra and interference), atomic force microscopy and measurement of water vapor permeability. Several pitfalls in the determination of water content of dried films that absorb water after being submerged in it have been proposed, such as fading boundaries, remaining water after drying and change of particle sizes. At moderately higher temperatures film formation is improved. This improvement follows from the formation of smoother film surfaces (AFM), lower water vapor permeabilities and smaller values for delta lambda(min). On the other hand, defects as cracks and channels also are created, especially at high temperatures. It appears, however, that these channels do not run from the one surface of a film to the other.

Journal Article↗
PubMed2004

Evaluation of the tear film stability after laser in situ keratomileusis using the tear film stability analysis system.

PURPOSE: To evaluate the tear film stability of patients before and after laser in situ keratomileusis (LASIK) using the tear film stability analysis system (TSAS). DESIGN: Prospective observational case series. METHODS: New videokeratography software for a topographic modeling system (TMS-2N) was developed that can automatically capture consecutive corneal surface images every second for 10 seconds. Thirty-four subjects (64 eyes) who underwent myopia LASIK were enrolled in this study. All subjects were examined with the new system before LASIK and at 1 week, 1 month, 3 months, and 6 months after the surgery. Corneal topographs were analyzed for tear breakup time (TMS breakup time) and breakup area (TMS breakup area). Based on pre-LASIK TSAS analysis, subjects were separated into normal and abnormal TSAS value groups. The criteria for the normal group were either TMS breakup time more than 5 seconds or TMS breakup area less than 0.2. The percentage of the occurrence of superficial punctuate keratitis was compared between the two groups with regard to subject's dry eye signs and symptoms. RESULTS: Tear film stability decreased significantly during the early period after LASIK, as indexed by decreased TMS breakup time and increased TMS breakup area. Tear film instability resolved at 6 months after surgery. Before LASIK, 22 subjects (43 eyes) had normal TSAS evaluation and 12 subjects (21 eyes) were abnormal. After LASIK, among normal TSAS value eyes, 8 of 43 (18.6%) eyes developed superficial punctuate keratitis. In sharp contrast, 14 of 21 (66.7%) eyes in the abnormal group displayed superficial punctuate keratitis, correlating well with the patients' dry eye symptoms. The difference in the presence of superficial punctuate keratitis after LASIK between normal and abnormal TSAS value groups was statistically significant (P <.001). Subjects with abnormal TSAS evaluation also displayed resistance to dry eye treatment and had extended period of recovery. CONCLUSIONS: Tear film stability analysis can be a useful means for screening LASIK candidates before surgery and for prognosticating dry eye symptoms thereafter.

Adult↗
PubMed1994

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↗
PubMed2005

MOCVD-derived highly transparent, conductive zinc- and tin-doped indium oxide thin films: precursor synthesis, metastable phase film growth and characterization, and application as anodes in polymer light-emitting diodes.

Four diamine adducts of bis(hexafluoroacetylacetonato)zinc [Zn(hfa)(2).(diamine)] can be synthesized in a single-step reaction. Single crystal X-ray diffraction studies reveal monomeric, six-coordinate structures. The thermal stabilities and vapor phase transport properties of these new complexes are considerably greater than those of conventional solid zinc metal-organic chemical vapor deposition (MOCVD) precursors. One of the complexes in the series, bis(1,1,1,5,5,5-hexafluoro-2,4-pentadionato)(N,N'-diethylethylenediamine)zinc, is particularly effective in the growth of thin films of the transparent conducting oxide Zn-In-Sn-O (ZITO) because of its superior volatility and low melting point of 64 degrees C. ZITO thin films with In contents ranging from 40 to 70 cation % (a metastable phase) were grown by low-pressure MOCVD. These films exhibit conductivity as high as 2900 S/cm and optical transparency comparable to or greater than that of commercial Sn-doped indium oxide (ITO) films. ZITO films with the nominal composition of ZnIn(2.0)Sn(1.5)O(z)() were used in fabrication of polymer light-emitting diodes. These devices exhibit light outputs and current efficiencies almost 70% greater than those of ITO-based control devices.

Journal Article↗
PubMed2006

Gamma-irradiation influence on the structure and properties of calcium caseinate-whey protein isolate based films. Part 1. Radiation effect on the structure of proteins gels and films.

Brookfield viscosimetry, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), and measurements of the texture strength of gels formed with CaCl2 and the mechanical and barrier properties of the film were applied in studies of gel formation and structural and mechanical properties of gels and films prepared using calcium caseinate (CC)-whey protein isolate (WPI)-glycerol (1:1:1), control, and irradiated with 60Co gamma rays using a 32 kGy dose. The irradiated gels have appeared to be more "fine-stranded" as compared to the more "particulate" control gels and lead to the formation of more rigid films with improved mechanical strength and barrier properties. This results from cross-linking and the modification of protein conformations were induced by irradiation, in particular the increase in the beta-sheet and beta-strand contents. Structural modifications taking place in CC-WPI composition are related to modifications taking place separately in CC and WPI. Improvement of the properties of the films after irradiation corresponds to the increased density of the cross-linked material because no change in the porosity of the films was observed by TEM.

Caseins↗
PubMed2006

Gamma-irradiation influence on the structure and properties of calcium caseinate-whey protein isolate based films. Part 2. Influence of polysaccharide addition and radiation treatment on the structure and functional properties of the films.

The influence of gamma-irradiation (32 kGy) followed by the addition of polysaccharides (potato starch, soluble potato starch, and sodium alginate) and heating on the properties of the films based on calcium caseinate (CC)-whey proteins isolate (WPI) and the gels formed with CaCl(2) was evaluated. Radiation induced an improvement of the mechanical and barrier properties of all films. The polysaccharides' effect on the irradiated and non-irradiated CC-WPI gels could be predicted as the sum of their separate effects on CC and on WPI, apart from the alginate interaction with the irradiated CC-WPI. The better properties of the films achieved after admixing polysaccharides to the formerly irradiated protein solution correspond to the smaller strength of gels. Properties of the films and gels prepared using the irradiated proteins and alginate differed depending on whether alginate was admixed before or after irradiation. Results were related to the protein structure, interaction with polysaccharides, and the film's microstructure.

Caseins↗
PubMed2006

Interaction forces in thin liquid films stabilized by hydrophobically modified inulin polymeric surfactant. 1. Foam films.

Using the interferometric method of Scheludko-Exerowa for investigation of foam films, we have obtained results using a hydrophobically modified inulin polymeric surfactant (INUTEC SP1). Measurements were carried out at constant INUTEC SP1 concentration of 2 x 10(-)(5) mol.dm(-)(3) and at various NaCl concentrations (in the range 1 x 10(-)(4) to 2 mol.dm(-)(3)). At constant capillary pressure of 50 Pa, the film thickness decreased gradually with an increase in NaCl concentration up to 10(-)(2) mol.dm(-)(3) NaCl above which the film thickness remains virtually constant at about 16 nm. This reduction in film thickness with an increase in NaCl concentration is due to the compression of the double layer and at the critical electrolyte concentration (C(el,cr) = 10(-)(2) mol.dm(-)(3)) the electrostatic component of the disjoining pressure is completely screened and the remaining pressure is due to the steric interaction between the adsorbed polymer layers. Disjoining pressure-thickness (Pi-h) isotherms were obtained at C(el) < C(el,cr) (10(-)(4) - 10(-)(3) mol.dm(-)(3)) and C(el) > C(el,cr) (0.5, 1, and 2 mol.dm(-)(3)). In the first case, the disjoining pressure isotherms could be fitted using the classical DLVO theory, Pi = Pi(el) + Pi(vw), and using the constant charge model. At C(el) > C(el,cr), the main repulsion is due to the steric interaction between the polyfructose loops that exist at the air-water interface, i.e., Pi = Pi(st) + Pi(vw). Under these conditions, there is a sharp transition from DLVO to non-DLVO forces. In the latter case, the interaction could be described using the de Gennes' scaling theory. This gave an adsorbed layer thickness of 6.5 nm which is in reasonable agreement with the values obtained at the solid-solution interface. The Pi-h isotherms showed that these foam films are not very stable and they tend to collapse above a critical capillary pressure (of about 1 x 10(3) Pa), and these results could be used to predict the foam stability.

Electrolytes↗
PubMed2006

Foam films stabilized with dodecyl maltoside. 2. Film stability and gas permeability.

The gas permeability and stability of foam films stabilized by n-dodecyl-beta-D-maltoside (beta-C(12)G(2)) were determined. The permeability coefficient (K, cm/s) and the mean film lifetime were measured as a function of the surfactant concentration. The films are less permeable than those stabilized by other surfactants at comparable conditions. The permeability coefficient decreases with increasing surfactant concentration. It does not show a remarkable dependence on the salt concentration. Stable Newton black foam films (NBFs) are formed above a surfactant concentration of 3.9 x 10(-)(6) M beta-C(12)G(2) in the presence of 0.2 M NaCl. The theory of nucleation hole formation in NBFs was applied to describe the observed dependencies of the permeability and film stability on the surfactant concentration. The theory gave satisfactory relation to the experiment.

Detergents↗
PubMed1976

[Logetronic micro-film in radiological diagnosis with an integrated system of filming and filing(author's transl)].

The results of one year's routine use of primary microfilm in a large diagnostic radiological institute is reviewed. Positive views were treated by electronic contrast enhancement in an integrated system of immediate filming and filing. The resulting changes and improvements in running the department are described. This involves a fundamental reorganisation of the department, as well as equipment which is not yet commercially available. The latter had therefore to be improvised and is described. Similar procedures introduced elsewhere are critically evaluated. The advantages of immediate filming are stressed and a comparison with conventional large film filing demonstrates its financial advantages. Logical application of the method results in saving in personnel and material, but implies that the radiologist must be prepared to change to positive films in routine diagnosis. By using microfilm positives with a resolution of 4.0 pairs of lines per mm., the results equal those from large film negatives.

Archives↗
PubMed1997

Limited usefulness of traction-compression films in the radiographic diagnosis of lumbar spinal instability. Comparison with flexion-extension films.

STUDY DESIGN: A prospective, within-patient comparison of two methods for functional radiography of lumbar spine with consecutive patients. OBJECTIVE: To evaluate the usefulness of traction-compression radiography compared with conventional flexion-extension radiography in diagnosis of lumbar spinal instability. SUMMARY OF BACKGROUND DATA: Flexion-extension radiography generally is used and widely recognized as an effective method for diagnosis of segmental lumbar spinal instability, but the usefulness and findings of traction-compression films are less well known. METHODS: Flexion-extension and traction-compression radiography were performed on 306 consecutive patients (mean age, 43 years; range, 14-68 years) with clinically suspected lumbar spinal instability. Radiography was performed of each patient in an upright position. Axial traction was accomplished by letting the patient hang by his or her hands from a horizontal bar. Compression views were taken when the patient had sandbags of approximately 30% of the his or her weight on the shoulders. Main interest was translational forward and backward displacement of one vertebra on another. RESULTS: Signs of translational instability were present on the functional radiographs of 27% (84 of 306) of the patients. In diagnosis of instability, the overall agreement of flexion-extension and traction-compression films was only 0.786, and also statistic Kappa remained poor (0.05). Flexion-extension films more frequently revealed signs of instability than traction-compression films: 81 versus seven patients. CONCLUSIONS: Traction-compression films seem to be of questionable value in diagnosis of lumbar spinal instability.

Adolescent↗
PubMed2002

Viscosity of entangled polystyrene thin film melts: Film thickness dependence.

We determined the low-shear effective viscosity of entangled polystyrene thin film melts, in the thickness range of 27<h<100 nm, on SiO(x)/Si substrates. This was accomplished using a method based on the notion that thin liquid films can become unstable and rupture due to defects or to destabilizing, long-range van der Waals interactions (dewetting). The holes that are created in the film subsequently grow at a rate determined by a balance between the capillary driving forces and the viscous resistive forces. Based on the velocity of growth of holes on the substrate, we show that the viscosity decreases appreciably with decreasing thickness for 25<h<50 nm. These results are consistent with studies which suggest that the glass transition of entangled polystyrene thin film melts on SiO(x)/Si substrates exhibit an apparent decrease with decreasing film thickness over the same range of h.

Journal Article↗