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PubMed1978

Performance comparison of the Corning thin-film agarose and the Hyland thick-film agar methods for immunoelectrophoresis.

Many clinical laboratories do immunoelectrophoresis for qualitative assessment of proteins in biological fluids. Commercial kits are available that supply some or all of the necessary components, but the nature of these components varies. Seeking a reliable method for most easily preserving the original immunoelectrophoresis pattern as a permanent record, we compared a thick-film agar method to a thin-film agarose method in immunoelectrophoresis of a total of 70 serum and urine samples. For each sample, either method resulted in the same interpretation. The thin-film agarose method not only yields a stained, permanent record in about the same time that the thick film agar is ready for interpretation but not preservation, but also requires less antiserum, a smaller sample, and may not require purchase of additional hardware.

Blood Proteins↗
PubMed1995

[Thoracic radiography in intensive care units. Comparison of an asymmetric film-screen-grid combination with an L-film].

PURPOSE: Using an asymmetrical screen-film-grid combination with an ITC-VHC special grid (Kodak), the effect of the individual components was evaluated with regard to detail in the lungs and mediastinum as well as patient dose. MATERIALS AND METHODS: The system was compared with the Curix Ortho screen film system (Agfa L-film) using phantoms and 62 patients in an intensive care unit. The results were analysed by three independent observers. Dose measurements on phantoms were carried out with a WD 10 (Wellhoefer) dosimeter and with a thermoluminescence dosimeter for patients. RESULTS: Both phantom and patient images showed improved demonstration of mediastinal structures with similar details of lung structure. Details in the peripheral lungs are significantly better shown with the ITC-VHC system with the special grid than they are without the grid. However, there is an increase about three to four times in radiation dose when using the grid. CONCLUSION: Our trial shows that the use of the ITC-VHC grid system is to be recommended for routine clinical use because of the better demonstration of details, but one must be aware of the increased radiation dose to the patient.

Evaluation Studies as Topic↗
PubMed2001

Clinical study of the sensitivity and dynamic range of three digital systems, E-speed film and digitized film.

The objective of the present study was to clinically evaluate the sensitivity and dynamic range of three digital systems (Sens-A-Ray, CDR, Digora), digitized film and E-speed film. Five objects were submitted to three different kilovoltages and seven exposure times. In order to evaluate the relationship between exposure time and dosage, measurements were made in a dental x-ray unit with an ion chamber, X-ray timer and kVp meter. For each system, 105 radiographs were taken, totalling 525 images, that were evaluated by six trained observers by means of scoring from 0 to 4. The scores attributed to the images for each of the systems were submitted to analysis of variance and Turkey's test. The results showed statistically significant differences (p < 0.01) with the storage phosphor system producing the wider dynamic range, followed by the digitized film. The CDR system showed the greater sensitivity, followed by the Digora system.

Analysis of Variance↗
PubMed1986

[Comparison of a standard x-ray film with a high-latitude film in thoracic diagnosis].

A comparison of chest radiographs using two films of different gradation (Cronex 4 and Cronex L (R)) shows that the relevant structures are visualized if the technique is optimal, and that the assessment speed is not prolonged. For visualizing the peripheral vessels it seems to be particularly important to employ a technique that provides rich contrasts. However, the less contrasty film makes it definitely easier to visualize the mediastinal structures and the retrocardial vessels. Imaging of the costopleural marginal zone was hardly improved by the L film type, using the technique employed here.

Humans↗
PubMed1985

[Results of a study on roentgen film processing in automatic film-developing systems].

100 X-ray film developing machines in 72 institutes were tested for accuracy of reproduction of the film developing systems by means of sensitometric methods for a period of 9 months. If we assume the sensitivity index to be D = 1.0 with a maximum variation of +/- 0.2, one-third of the machines in this test are not within the standard range. Hence, to ensure maximum utilisation of the sensitivity of the film processing systems, it will be necessary to keep a close check on the development process.

Germany, West↗
PubMed2000

The Film Formation of Polymer Particles in Drying Thin Films of Aqueous Acrylic Latices.

The aim of this study is to determine the factors that contribute to the process of film formation of binder particles in drying aqueous dispersion coatings, based on acrylic polymers. It is known that concentrated latices of uniform size show iridescent, colored light patterns. These colors are caused by interparticle interference, and they are only present when the latex particles are ordered in a regular structure. The interparticle interference can be characterized by measuring the transmission as a function of wavelength of the incident light. It appeared that the changes of the interparticle interference of a drying latex film can be related to changes in the interparticle distance and displacement. It was also found that the interparticle distance becomes "negative" upon coalescence of the latex particles. This means that from this point on, the change in interparticle interference is directly related to the indentation or deformation of the latex particles. It became clear that the coalescence process differs from deformation mechanisms accepted in the literature. It seems that the deformation of the particles follows a biaxial mechanism. This means that the particles deform only in one direction, perpendicular to the film surface. Copyright 2000 Academic Press.

Journal Article↗
PubMed1991

Radiographic detection of occlusal caries in noncavitated teeth. A comparison of conventional film radiographs, digitized film radiographs, and RadioVisioGraphy.

The aim of this study was to compare the accuracy of conventional film radiographs, digitized radiographs, and RadioVisioGraphy (RVG) for the detection of dentinal caries in occlusal surfaces of noncavitated extracted teeth. Eighty-one fully erupted extracted third molars were assessed by four observers using five radiographic methods: conventional film radiographs, digitized radiographs with contrast enhancement and with a filtering procedure, and RVG with contrast enhancement and with x function. Scoring criteria were dichotomous. Histologic sections (500 to 600 microns thick) served as the validation criterion. The two digital methods with contrast enhancement tended to perform more accurately than, although not significantly different from, the other three methods (p greater than 0.05). Average likelihood ratios (true positive/false positive) were 4.3 (conventional film radiographs), 4.4 (RVG with contrast enhancement), 3.6 (RVG with x function), 4.9 (digitized radiographs with contrast enhancement), and 3.7 (digitized radiographs with filtering procedure). Observers 1 and 2 (oral radiologists) performed better than observers 3 and 4 with all five methods (p less than 0.005).

Adolescent↗
PubMed2006

Nafion-coated bismuth film and nafion-coated mercury film electrodes for anodic stripping voltammetry combined on-line with ICP-mass spectrometry.

Nafion-coated bismuth film electrodes (NCBFEs) and Nafion-coated mercury film electrodes (NCMFEs) were used to electrochemically preconcentrate metal analytes for subsequent analysis by inductively coupled plasma-mass spectrometry (ICP-MS). Either type of electrodes is part of a thin-layer electrochemical flow cell that is positioned upstream of a microconcentric nebulizer for the ICP-MS. Performances of these electrodes were compared in terms of the analytical "figures of merit" (e.g., dynamic ranges, reproducibility, hydrodynamic stability, and elimination of matrix effects detrimental to ICP-MS). The coupled technique (ASV-ICP-MS) is found to possess a wide dynamic range (at least 4 to 5 orders of magnitude) and to be reproducible. Both electrodes are much more stable than the thin mercury film electrode (TMFE) traditionally used for ASV-ICP-MS, with the lifetime of the NCBFE exceeding 8 h. Adopting these electrodes for ASV-ICP-MS overcomes the problems associated with a TMFE, the erosion of which decreases the sample throughput, affects the analysis precision, and contaminates conventional glass nebulizers and spray chambers of the spectrometer. The medium exchange procedure inherent in ASV is successfully implemented with a two-valve flow injection system for the accumulation of trace Cd2+ into the electrode from a certified seawater sample, followed by stripping Cd into a solution that is compatible to the ICP-MS operation.

Adsorption↗
PubMed2003

Phospholipid black foam films: dynamic contact angles and gas permeability of DMPC bilayer films.

The behavior of bilayer Newton Black Films (NBF) from aqueous dispersions of dimyristoylphosphatidylcholine (DMPC) have been studied in dynamic conditions. The dynamic contact angles theta and the gas permeability coefficient K have been measured using the diminishing bubble method. Two different solutions have been used: (i) DMPC vesicle suspension in water obtained through sonication and (ii) DMPC dissolved in ethanol plus water mixed solvent. Both solutions contain 0.1 M NaCl. The behavior of the dynamic contact angles is very different for NBF from the two types of solutions. In the case (i) the initially constant theta(t) sharply increase after approximately 2 h of the spontaneous diminishing of the bubble, they follow the gas pressure variation in the cell and depend on the film area. On the contrary in case (ii) the theta(t) values are almost constant during the spontaneous diminishing of the bubble as well as during the gas pressure variation in the cell and they do not depend on the film area. The gas permeability coefficient is larger in case (ii). The results are discussed in connection with the thickness and structure of the NBF from the two types of solutions, taking into account the solubility (or insolubility) and the hydration of the adsorption layers of the DMPC molecules.

Dimyristoylphosphatidylcholine↗
PubMed2004

Reduction of Cr(VI) at a polyaniline film: influence of film thickness and oxidation state.

Hexavalent chromium [Cr(VI)] is highly toxic, carcinogenic, and mutagenic to living organisms. In this paper, the reduction of Cr(VI) to the much less toxic trivalent state [Cr(III)] was studied at polyaniline films grown to different thickness. Much higher rates of Cr(VI) reduction were observed for the "thick" polyaniline films. This was explained in terms of the morphology of the polymer and the higher surface area of polymer in contact with the Cr(VI) solution. For "thin" polyaniline films, the Cr(VI) reduction reaction was found to obey pseudo-first-order kinetics for the duration of exposure. However, in the case of thick polyaniline layers, the Cr(VI) reduction reaction followed a two-stage process, with each stage obeying pseudo-first-order kinetics. This was explained in terms of oxidation of the polymer from the leucoemeraldine to the emeraldine state and then further oxidation of the polymer from the emeraldine to the pernigraniline state. Much higher rates of Cr(VI) reduction were observed on oxidation of the polymer from the leucoemeraldine to the emeraldine state.

Aniline Compounds↗
PubMed2006

Strategies for electrooptic film fabrication. Influence of pyrrole-pyridine-based dibranched chromophore architecture on covalent self-assembly, thin-film microstructure, and nonlinear optical response.

The new dibranched, heterocyclic "push-pull" chromophores bis{1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane (1), 1-(pyrid-4-yl)-2-(N-methyl-5-formylpyrrol-2-yl)ethylene (2), {1-(N-methylpyridinium-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}{(1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane (3), N-methyl-2-[1-(N-methylpyrid-4-yl)ethen-2-yl]-5-[pyrid-4-yl]ethen-2-yl]pyrrole iodide (4), bis{1-(N-methyl-4-pyridinio)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane iodide (5), and N-methyl-2,5-[1-(N-methylpyrid-4-yl)ethen-2-yl]pyrrole iodide (6) have been synthesized and characterized. The neutral (1 and 2) and monomethyl salts (3 and 4) undergo chemisorptive reaction with iodobenzyl-functionalized surfaces to afford chromophore monolayers SA-1/SA-2 and SA-3/SA-4, respectively. Molecular structures and other physicochemical properties have been defined by (1)H NMR, optical spectroscopy, and XRD. Thin-film characterization by a variety of techniques (optical spectroscopy, specular X-ray reflectivity, atomic force microscopy, X-ray photoelectron spectroscopy, and angle-dependent polarized second harmonic generation) underscore the importance of the chromophore molecular architecture as well as film growth method on film microstructure and optical/electrooptic response.

Journal Article↗
PubMed2005

Refractive index measurements of films with biaxial symmetry. 2. Determination of film thickness and refractive indices using polarized transmission spectra in the transparent wavelength range.

A technique is formulated to determine both thickness and refractive indices of free-standing films with biaxial symmetry from polarized transmission spectra. The films must be transparent and show little dispersion in refractive indices in the wavelength range where the transmission spectra are collected. Methods are proposed to correct the errors caused by imperfect polarization of incident radiation and thickness variation across the sampling area. Anisotropic refractive indices and thickness of poly(biphenyl dianhydride-p-phenylenediamine) films which exhibit uniaxial optical anisotropy are determined from polarized transmission spectra. The refractive index and thickness values compare well to those obtained from waveguide prism coupler and profilometer measurements.

Journal Article↗
PubMed2004

Controlled growth of micropatterned, oriented calcite films on a self-assembled multilayer film.

A micropatterned multilayer film, which was fabricated from layer-by-layer electrostatic self-assembly of nitrodiazoresin (NDR)/poly(acrylic acid) (PAA) followed by photolithography, was utilized as a structured template for the biomimetic mineralization of calcium carbonate. Micropatterned CaCO3 films consisting of regularly aligned calcite crystals oriented in the <104> direction were selectively deposited on the patterned NDR/PAA multilayer film.

Letter↗
PubMed1999

[The reduction of the radiation dosage by means of storage phosphor-film radiography compared to a conventional film-screen system with a grid cassette on a skull phantom].

PURPOSE: How much can the radiation dose be reduced for skull radiography by using digital luminescence radiography (DLR) compared to a conventional screen film system with a grid cassette? METHODS AND MATERIALS: A skull phantom (3M) was x-rayed in anterior-posterior orientation using both a conventional screen film system with grid cassette and DLR (ADC-70, Agfa). The tube current time product (mAs) was diminished gradually while keeping the voltage constant. The surface entrance dose was measured by a sensor of Dosimax (Wellhöfer). Five investigators evaluated the images by characteristic and critical features, spatial resolution and contrast. RESULTS: The surface entrance dose at 73 kV/22 mAs was 0.432 mGy in conventional screen film system and 0.435 mGy in DLR. The images could be evaluated very well down to an average dose of 71% (0.308 mGy; SD 0.050); sufficient images were obtained down to an average dose of 31% (0.136 mGy; SD 0.065). The resolution of the line pairs were reduced down to 2 levels depending on the investigator. Contrast was assessed as being very good to sufficient. The acceptance of the postprocessed images (MUSICA-software) was individually different and resulted in an improvement of the assessment of bone structures and contrast in higher dose ranges only. CONCLUSION: For the sufficient assessment of a possible fracture/of paranasal sinuses/of measurement of the skull the dose can be reduced to at least 56% (phi 31%; SD 14.9%)/40% (phi 27%; SD 9.3%)/18% (phi 14%; SD 4.4%). Digital radiography allows question-referred exposure parameters with clearly reduced dose, so e.g. for fracture exclusion 73 kV/12.5 mAs and to skull measurement 73 kV/4 mAs.

Evaluation Studies as Topic↗
PubMedDate not supplied

Migration from plasticized films into foods. 2. Migration of di-(2-ethylhexyl)adipate from PVC films used for retail food packaging.

A UK survey of di-(2-ethylhexyl)adipate (DEHA) levels in retail foods (83 samples) wrapped in plasticized PVC film has been carried out, examining a wide range of different food types obtained from retail and take-away outlets. Foodstuffs analysed included fresh meat and poultry, ready-cooked poultry, cheese, fruit, vegetables and baked goods such as cakes, bread rolls and sandwiches. Analysis by stable isotope dilution GC/MS showed DEHA levels ranging from 1.0 to 72.8 mg/kg in uncooked meat and poultry, 9.4 to 48.6 mg/kg in cooked chicken portions, 27.8 to 135.0 mg/kg in cheese, less than 2.0 mg/kg in fruit and vegetables and 11 to 212 mg/kg in baked goods and sandwiches. The level of DEHA migration correlated with the extent of contact between the film and exposed fatty portions of the food, whether that was the mayonnaise filling of a sandwich or the surface fat from a joint of uncooked meat. The level of DEHA in meat exposed to plasticized film was not reduced significantly by volatilization or chemical transformation on subsequent cooking by grilling or frying.

Adipates↗
PubMedDate not supplied

Migration from plasticized films into foods. 3. Migration of phthalate, sebacate, citrate and phosphate esters from films used for retail food packaging.

A UK survey of plasticizer levels in retail foods (73 samples) wrapped in plasticized films or materials with plasticized coatings has been carried out. A wide range of different food-types packaged in vinylidene chloride copolymers (PVDC), nitrocellulose-coated regenerated cellulose film (RCF) and cellulose acetate were purchased from retail and 'take-away' outlets. Plasticizers found in these films were dibutyl sebacate (DBS) and acetyl tributyl citrate (ATBC) in PVDC, dibutyl phthalate (DBP), dicyclohexyl phthalate (DCHP), butylbenzyl phthalate (BBP), and diphenyl 2-ethylhexyl phosphate (DPOP) in RCF coatings, and diethyl phthlate (DEP) in cellulose acetate. Foodstuffs analysed included cheese, pate, chocolate and confectionery products, meat pies, cake, quiches and sandwiches. Analysis was by stable isotope dilution GC/MS for DBP, DCHP and DEP, GC/MS (selected ion monitoring) for BBP and DPOP, and GC with flame ionization detection for DBS and ATBC, but with mass spectrometric confirmation. Levels of plasticizers found in foods were in the following ranges: ATBC in cheese, 2-8 mg/kg; DBS in processed cheese and cooked meats, 76-137 mg/kg; 76-137 mg/kg; DBP, DCHP, BBP, and DPOP found individually or in combination in confectionery, meat pies, cake and sandwiches, total levels from 0.5 to 53 mg/kg; and DEP in quiches, 2-4 mg/kg.

Chromatography, Gas↗
PubMed1999

Wavy film flows down an inclined plane: perturbation theory and general evolution equation for the film thickness.

Wavy film flow of incompressible Newtonian fluid down an inclined plane is considered. The question is posed as to the parametric conditions under which the description of evolution can be approximately reduced for all time to a single evolution equation for the film thickness. An unconventional perturbation approach yields the most general evolution equation and least restrictive conditions on its validity. The advantages of this equation for analytical and numerical studies of three-dimensional waves in inclined films are pointed out.

Journal Article↗