Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Films”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,351 records · Page 75Linked to original sources
PubMed1997

Plain film evaluation of degenerative disk disease at the lumbosacral junction.

OBJECTIVE: Diagnosing degenerative disk disease (DDD) at the lumbosacral junction (LSJ) on plain films is often difficult, compared with other disk levels. The purpose of this study was to determine whether criteria for diagnosis of DDD at the LSJ can be established for plain films. DESIGN AND PATIENTS: We retrospectively reviewed 100 lumbar MRI scans of patients who also had lumbar plain films. Using MRI as the reference standard, the LSJ was classified as normal (n=35) or exhibiting mild (n=45) or severe (n=20) DDD by two radiologists using accepted criteria. Measurements were performed on the plain films by two other radiologists and the average measurements were tabulated according to the three categories of DDD defined by MRI. Plain film measurements included the anterior and posterior disk heights (ADH, PDH), Farfan's ratio, determined by adding ADH to PDH and dividing that number by the measured anteroposterior (AP) length of the inferior end plate of L5 [(ADH+PDH)/AP length of L5], and lumbosacral angle (LSA). Subsequently, five additional radiologists interpreted the radiographs by visual inspection only, for DDD at the LSJ, both before and, several weeks later, after being provided with the quantitative data for normal versus DDD. RESULTS AND CONCLUSION: There was a statistically significant difference between normal disk and increasing severity of DDD on radiographs using the parameters of PDH and Farfan's ratio. There was no statistically significant difference regarding ADH or LSA. Diagnostic accuracy by visual inspection was not significantly altered using the quantitative data for interpretation of DDD (68% correct before, 69.5% correct after). Analysis of results indicates that PDH is the most reliable and easily used criterion for detection of DDD at the LSJ. A PDH < or =5.4 mm on plain lateral film indicates DDD; PDH > or =7.7 mm indicates the absence of DDD on plain film.

Adult↗
PubMed2007

A comparative study of conventional mammography film interpretations with soft copy readings of the same examinations.

An acceptable mammography film digitizer must provide high-quality images at a level of diagnostic accuracy comparable to reading conventional film examinations. The purpose of this study was to determine if there are significant differences between the interpretations of conventional film-screen mammography examinations and soft copy readings of the images produced by a mammography film digitizer. Eight radiologists interpreted 120 mammography examinations, half as original films and the other half as digital images on a soft copy work station. No radiologist read the same examination twice. The interpretations were recorded in accordance with the Breast Imaging Reporting and Data System and included other variables such as perceived image quality and diagnostic difficulty and confidence. The results provide support for the hypothesis that there are no significant differences between the interpretations of conventional film-screen mammography examinations and soft copy examinations produced by a mammography film digitizer.

Breast Neoplasms↗
PubMed2005

A new way of incorporating silicon in hydroxyapatite (Si-HA) as thin films.

Bioactive silicon-containing hydroxyapatite (Si-HA) thin films that can be used as coatings for bone tissue replacement have been developed. A magnetron co-sputtering technique was used to deposit Si-HA films up to 700 nm thick on titanium substrates, with a silicon level up to 1.2 wt%. X-ray diffraction demonstrated that annealing transformed the as-deposited Si-HA films which were amorphous, into a crystalline HA structure. A human osteoblast-like (HOB) cell model was used to determine the biocompatibility of these films. HOB cells were seen to attach and grow well on the Si-HA films, and the metabolic activity of HOB cells on these films was observed to increase with culture time. Furthermore, mineralisation of the cell layers was observed after 8 weeks of culture. Based on the present findings, Si-HA of different film compositions demonstrate bioactive properties in-vitro, and indicate the potential as biocoatings for a wide variety of medical implants including load-bearing applications such as the femoral stem of hip replacement implants.

Bone Substitutes↗
PubMed2006

Continuous measurement of the lipoxygenase-catalyzed oxidation of unsaturated lipids using the monomolecular film technique.

PURPOSE: This paper presents the first detailed kinetic investigation involving the continuous measurement of the soybean lipoxygenase 1 (LOX1)-catalyzed oxidation of unsaturated lipids using the monomolecular film technique at an argon/water interface. MATERIALS AND METHODS: The presence of oxidation products in the monolayer is qualitatively detected, at a constant area, by an increase in the monolayer surface pressure. Alternatively, the rate of lipid oxidation can be measured, at a constant surface pressure, by a backward movement of the mobile barrier, due to the oxidation-dependent increase in the monolayer area. RESULTS: For instance, the LOX1-catalyzed oxidation of 1,2-di[cis-9,12-octadecadienoyl]-sn-glycero-3-phosphocholine (diC18:2PC) monolayer was found to be characterized by a time dependent increase in the monolayer area, at constant surface pressure. However, the increase in the monolayer area was thought to be caused first by the penetration of the enzyme into the interface, and secondly, by the formation of hydroperoxides at the interface, due to the LOX1-catalyzed oxidation of the diC18:2PC film. The rate of the LOX1-catalyzed oxidation of diC18:2PC film was measured by subtracting the increase in the area due to the LOX1-penetration into the non-oxidizable 1,2-di[cis-9-octadecenoyl]-sn-glycero-3-phosphocholine (diC18:1PC) film from the increase in the area due to LOX penetration and oxidation of the diC18:2PC film. At a constant optimum surface pressure of 1 mN m(-1), similar initial rates of LOX1-catalyzed oxidation are observed with both linoleic acid methyl ester (C18:2) and diC18:2PC. It is worth noting that the surface density of C18:2 acyl chains is also similar in both films. We observed that a phosphatidylcholine (PC) film with two potentially oxidizable chains (e.g., diC18:2PC) is oxidized at a rate which is twice that obtained with a PC containing a single oxidizable chain (e.g., 1-hexadecanoyl-2-[cis-9,12-octadecadienoyl]-sn-glycero-3-phosphocholine). CONCLUSIONS: The enzymatic lipid oxidation seems to occur when the monolayer is in the expanded state. This expanded state may possibly result in vivo from the lipolysis of a biomembrane and consequently lipolysis and lipid oxidation are coupled at the membrane level.

Catalysis↗
PubMed2006

The effect of film thickness on thermal aerosol generation.

PURPOSE: Rapid heating of thin films of pharmaceutical compounds can vaporize the molecules, which leads to formation of aerosol particles of optimal size for pulmonary drug delivery. The aim of this work was to assess the effect of coated film thickness on the purity of a thermally generated (condensation) drug aerosol. MATERIALS AND METHODS: Pharmaceuticals in their free base form were spray-coated onto stainless steel foils and subsequently heated and vaporized in airflow via a rapid resistive heating of the foil. Aerosol particles were collected on filters, extracted, and analyzed using reverse phase HPLC to assess the amount of degradation induced during the vaporization process. RESULTS: Condensation aerosols of five pharmaceuticals were formed from a wide range of film coating thicknesses. All five showed a roughly linear trend of increasing aerosol purity with decreasing film thickness, although with quite different slopes. These findings are consistent with a model based on general vaporization and degradation kinetics. Small non-uniformities in the film do not significantly alter aerosol purity. CONCLUSIONS: Rapid vaporization of pharmaceuticals coated as thin films on substrates is an efficient way of generating drug aerosols. By controlling the film thickness, the amount of aerosol decomposition can be minimized to produce high purity aerosols.

Aerosols↗
PubMed1975

Surface-bound aspartate aminotransferase on collagen films. Compared properties with native enzyme.

Aspartate aminotransferase (L-aspartate : 2-oxoglutarate aminotransferase, EC 2.6.1.1) has been covalently bound to chemically activated collagen films. This enzyme had never previously been coupled to any other solid support. The coupling method, including acyl azide formation on the carrier, allowed coupling of many other enzymes. A systematic study of coupling conditions has been performed; influence of time of coupling and of concentration of coupling solution on the enzymatic activity retained on the film. Coupling solutions could be used for several successive couplings. To determine the yield of binding, N-[14C] ethylmaleimide-labelled enzyme was prepared fully active and bound to collagen films. After lyophilisation the film retained most of its activity when stored in buffer and the half-life of the enzymatic film was about ten months. pH Dependence and activation energy were about the same for soluble and coupled enzyme. Coupling protects against thermal denaturation and increases the stability of the enzyme; the enzymatic film could be used repeatedly. Kinetics were somewhat modified in the coupled enzyme as compared to the enzyme in solution. Glutamate appeared more available while oxaloacetate seemed to be limiting. These modifications might be due to the proteic support itself. The enzymatic films also revealed themselves as a good tool for industrial or clinical purposes as well as for studying the mechanism of enzyme action.

Aspartate Aminotransferases↗
PubMed1995

The role of synovial fluid filtration by cartilage in lubrication of synovial joints--III. Squeeze-film lubrication: axial symmetry under low loading conditions.

A mixture model of synovial fluid filtration and synovial gel formation at normal approach of cartilage surfaces in the human synovial joints loaded by a compressive force has been recently presented in Parts I and II of this paper (Hlavácek, 1993, J. Biomechanics 26, 1145-1150; 1151-1160). In the model synovial fluid is taken as a mixture of two incompressible fluids (ideal and Newtonian viscous), while the biphasic model of Mow et al. (1980, J. Biomech. Engng 102, 73-84) is used for cartilage. A system of partial differential equations for the normal approach of axially symmetric cartilage surfaces in the human hip joint obtained in Part II is solved numerically for low loads. A shallow pocket-type configuration of the synovial film is formed shortly after the load application at time t = 0. For constant loads the fluid film pressure profile follows very closely that in a dry frictionless contact. To this approximation and with the exception of a close vicinity of the squeeze-film edge the flux of the ideal fluid across the synovial fluid-cartilage interface varies quadratically with the radial distance r and decreases as t-1/2 with time. The ideal fluid is forced into cartilage at the central region and out of cartilage at the low-pressure periphery of the squeezed synovial film. The maximum gel-forming concentration (the 20-fold of the original value) of the hyaluronic acid-protein macromolecular complex of the synovial fluid is reached at the film centre first, then the gel film starts spreading quickly sideways. Later, the process slows down approaching the value r/2 1/2 where r is the radius of a dry frictionless contact. The final gel-film thickness decreases very slowly with the increasing r for 0 < or = r < r/2 1/2.

Biomechanical Phenomena↗
PubMed1977

Specific separation of cytotoxic T lymphocytes on immunoadsorptive films.

A method for the specific separation of cytotoxic T lymphocytes (CTL) on immunoadsorptive films is described. The films were prepared by polymerizing a mixture of gelatine and polyethyleneimine with glutaraldehyde on the bottom of plastic tissue culture flasks. By using an excess of glutaraldehyde unsaturated aldehyde groups on the film surface can react with other chemical groups predominantly with aliphatic amino groups. In this study detergent solubilized H-2 antigens were conjugated covalently to the films CTL, prepared by filtering spleen cells from alloimmunized mice through nylon wool columns, were incubated on immunoadsorptive films and the adsorbed cells were quantitatively recovered by mechanical detachment. The cells were functionally intact and tested in a microcytotoxicity assay using embryonic fibroblasts as target cells. Specificity adsorbed cells were enriched in specific cytotoxic cells up to 100 fold compared to the original fraction. Depending on the cell density per film area the non-adsorbed cells could be quantitatively depleted of CTL. The immunoadsorptive films are stabile at 37 degrees C and can be reused.

Animals↗
PubMed1994

Luting cement-metal surface physicochemical interactions on film thickness.

Low film thickness is critical to the clinical success of cemented castings. This study investigated the effect of luting agent-metal physico-chemical surface interactions on film thicknesses of representative luting agents. Control group luting agents were placed between two glass plates, as described by American Dental Association specifications 8, 61, and 66, and test group luting agents were positioned between glass and metal plates. The materials selected were zinc phosphate cement, polycarboxylate cement, glass ionomer cement, glass ionomer-composite resin hybrid cement and a resinous cement, with a type III gold alloy, a noble metal ceramic alloy, and a base metal ceramic alloy. A two-way analysis of variance and follow-up tests were done. The effects of the type of metal surface, type of cement, and their statistical interaction significantly affected film thickness (p < 0.0001). The type of cement had a greater affect on film thickness than the type of metal. A glass ionomer cement produced lower overall film thicknesses than other cement types, and a noble metal ceramic alloy created lower overall film thicknesses than other types of metal. American Dental Association specifications for cement film thickness did not accurately reflect normal cement use.

American Dental Association↗
PubMed1996

Quantitative assessment of the tissue response to films of hyaluronan derivatives.

The aim of this study was to evaluate the in vivo response following implantation into a rat model of three innovative hyaluronan derivatives for clinical use: HYAFF 7, HYAFF 11 and HYAFF 11p75 (respectively, the 100% ethyl ester, 100% and 75% benzyl esters). The tissue reaction evoked by films of these new biomaterials implanted into the dorsolumbar musculature of rats was assessed quantitatively using a well established technique based upon an image analysis system. The number of inflammatory cells present and the patterns of cell distribution around the implant up to a distance of 642 microns were examined at different time periods after implantation. Since a well-delineated tissue-material interface was needed for this type of investigation, it was not possible to apply image analysis to sections once dissolution of the implanted materials had begun. Films of both the total esters, HYAFF 7 and HYAFF 11, were found to undergo a slow dissolution process and, after a month, films of these materials were still present at the site of implantation. Differences in response to the two materials were observed only during the first two weeks, particularly with respect to neutrophil distribution and total cellularity. HYAFF 7 was found to be more reactive, with higher numbers of neutrophils near the surface of the implant than HYAFF 11. Thereafter, the differences between the two materials were minimal and owing mainly to a faster dissolution of HYAFF 7 films. After 3 and 5 months, considerable degradation of films of both total esters had occurred. Significant quantities of material appeared inside numerous macrophages with an ED1-positive phenotype. Only a very thin layer of fibrous connective tissue, indicative of low reactivity, was found to surround the site of implantation, separating the dissolved material and the phagocytic cells from healthy muscular tissue. ED2-positive macrophages were primarily confined within the lining connective tissue. The partial benzyl ester, HYAFF 11p75, showed a different behaviour. In fact, evidence of film dissolution was already present a week after the implantation. After two weeks, the implanted films were completely dissolved and numerous ED1-positive macrophages phagocytosing the material were observed at the site of implantation. Therefore, in agreement with previous in vitro studies, which showed a greater susceptibility to degradation of hyaluronan derivatives with lower percentage of esterification, HYAFF 11p75 underwent resorption faster than the corresponding total ester.

Animals↗
PubMed1991

Early breast cancer irradiation after conservative surgery: quality control by portal localization films.

A review of geometrical errors on portal localization films in 20 patients undergoing breast irradiation after conservative surgery is presented. Patients were immobilized using a cellulose acetate individual cast. Good precision in daily set-up has been noted with a mean ventrodorsal shift of 2.7 mm on medial films and 3.0 mm on lateral films; a mean craniocaudal shift of 1.8 mm on medial films and of 2.0 mm on lateral films have been also observed. The mean half-beam block rotation error has been minimal, ranging 0.8 degrees on medial and 1.1 degrees on lateral films. A new cast was made in 3/20 (15%) patients depending on variation of breast morphology during treatment and on geometrical errors noted by portal localization film check.

Breast Neoplasms↗
PubMed1991

Autonomic, neuroendocrine, and subjective responses to emotion-inducing film stimuli.

The aim of the present study was to investigate differential emotional response patterns to film stimuli by multimodal assessment of subjective, autonomic and endocrine variables. Scenes of two films, chosen to induce different affective states, were presented to 20 male subjects. Changes in mood and perceived bodily sensations, autonomic activity (heart rate and skin conductance) and one endocrine parameter (salivary cortisol) were measured. Analyses revealed that the films elicited differential mood patterns. The cartoon film, which induced a pleasant, amused state, was accompanied by very few changes in bodily sensations, a temporary decrease in heart rate, and a rapid decrease in electrodermal activity. The suspense film, which elicited a marked reduction in joyfulness and relaxation together with an enhancement in irritation, differed from that pattern primarily by marked changes in several bodily sensations, an increase in electrodermal activity, and a temporary decrease in heart rate. There were no film-dependent cortisol changes. The results together with evidence from other emotion induction experiments support the usefulness of film segments in eliciting mild to moderate affective states and their concomitances. They particularly point to the relevance of bodily sensations as an emotional response component.

Adult↗
PubMed1990

Neuroendocrine hemisphere asymmetries: salivary cortisol secretion during lateralized viewing of emotion-related and neutral films.

The study set out to examine whether the cerebral hemispheres differ in their ability to regulate cortisol secretion during emotion-related situations. One hundred twenty-three adult subjects were shown either an emotionally aversive or a neutral film in the left or right hemisphere by means of a technique for lateralizing visual input that allows prolonged viewing while permitting free ocular scanning. The film-related changes of cortisol secretion were determined by salivary cortisol radioimmunoassay. Right hemispheric viewing of the emotionally aversive film resulted in a significantly higher increase of cortisol secretion than left hemispheric viewing of the same film. No such differences were observed with respect to the neutral film. Comparing the effects of the two films separately for each hemisphere revealed that only the right hemisphere was able to respond neuroendocrinologically in a different manner to the emotional and the neutral film. Therefore, it is concluded that cortical regulation of cortisol secretion in emotion-related situations is under primary control of the right hemisphere. The potential implications of asymmetric control of cortisol secretion with respect to the pathogenesis of psychosomatic and immunological disorders are discussed.

Adolescent↗
PubMed1996

An observer study for direct comparison of clinical efficacy of electronic to film portal images.

PURPOSE: To directly compare clinical efficacy of electronic to film portal images. METHODS AND MATERIALS: An observer study was designed to compare clinical efficacy of electronic to film portal images acquired using a liquid matrix ion-chamber electronic portal imaging device and a conventional metal screen/film system. Both images were acquired simultaneously for each treatment port and the electronic portal images were printed on gray-level thermal paper. Four radiation oncologists served as observers and evaluated a total of 44 sets of images for four different treatment sites: lung, pelvis, brain, and head/neck. Each set of images included a simulation image, a double-exposure portal film, and video paper prints of electronic portal images. Eight to nine anatomical landmarks were selected from each treatment site. Each observer was asked to rate each landmark in terms of its clinical visibility and to rate the ease of making the pertinent verification decision in the corresponding electronic and film portal images with the aid of the simulation image. RESULTS: Ratings for the visibility of landmarks and for the verification decision of treatment ports were similar for electronic and film images for most landmarks. However, vertebral bodies and several landmarks in the pelvis such as the acetabulum and public symphysis were more visible in the portal film images than in the electronic portal images. CONCLUSION: The visibility of landmarks in electronic portal images is comparable to that in film portal images. Verification of treatment ports based only on electronic portal images acquired using an electronic portal imaging device is generally achievable.

Observer Variation↗
PubMed2005

An amperometric hydrogen peroxide sensor based on immobilization of hemoglobin in poly(o-aminophenol) film at iron-cobalt hexacyanoferrate-modified gold electrode.

A series of hybrid iron-cobalt hexacyanoferrate (FeCoHCF) films were electrodeposited on gold electrodes from solutions containing 6mM Fe(CN)(6)(3-) with different concentrations of Co(2+) and Fe(3+). FeCoHCF films deposited from solutions with different molar ratios of iron were studied by cyclic voltammetry, and their solid states were characterized by Fourier transform infrared spectroscopy. The kind of FeCoHCF film that deposited from a solution with a molar ratio of iron of 0.4 showed the largest response current to H(2)O(2) and was characterized by energy-dispersive X-ray spectroscopy. Therefore, the optimized FeCoHCF film was combined with nonconducting poly(o-aminophenol) (POAP) film that entrapped the hemoglobin (Hb) to construct hydrogen peroxide biosensor. The response current of the Hb/POAP/FeCoHCF/Au electrode (29.8 nA) was nearly 40 and was 1.5 times that of the Hb/POAP/Au (0.7 nA) and POAP/FeCoHCF/Au (20 nA) electrodes, respectively. The Michaelis-Menten constant of Hb in the Hb/POAP/FeCoHCF/Au film was 9.31 mM. These results show that the immobilized Hb in the Hb/POAP/FeCoHCF/Au film exhibits higher catalytic activity and larger response current to H(2)O(2) by the mediation of FeCoHCF. In addition, effects of applied potential, solution pH, and electroactive interferent on the response current of the Hb/POAP/FeCoHCF/Au electrode were investigated in detail.

Aminophenols↗
PubMed2004

Diagnostic accuracy of Fischer Senoscan Digital Mammography versus screen-film mammography in a diagnostic mammography population.

RATIONALE AND OBJECTIVES: To compare the diagnostic accuracy of the Fischer Senoscan Digital Mammography System with that of standard screen-film mammography in a population of women presenting for screening or diagnostic mammography. MATERIALS AND METHODS: Enrollment of patients took place at six different breast-imaging centers between 1997 and 1999. A total of 247 cases were selected for inclusion in the final reader study. All known cancer cases were included (111) from all six participating sites representing 45% of the total cases. The remaining 136 cases (55%) were randomly selected from all available benign or negative cases from three of the six sites. A complete case consisted of both a (unilateral or bilateral) digital and screen-film mammogram of the same patient. Eight radiologists interpreted the cases in laser-printed digital and screen-film hardcopy formats. The study was designed to detect differences of 0.05 in the ROC area under the curve (AUC) between digital and screen-film radiologist interpretation performance. RESULTS: The average AUC for the Senoscan digital was 0.715 for the 8 readers. The average AUC for screen-film was 0.765. The difference AUC of -0.05 falls within the 95% confidence interval (-0.101, 0.002). The average sensitivity was 66% and specificity 67% for SenoScan full-field digital mammography. The average screen-film mammography sensitivity and specificity were 74% and 60%, respectively. CONCLUSION: No statistically significant difference in diagnostic accuracy between the Fischer Senoscan and screen-film mammography was detected in this study.

Adult↗
PubMed2005

Multilayer assembly of calf thymus DNA and poly(4-vinylpyridine) derivative bearing [Os(bpy)(2)Cl](2+): redox behavior within DNA film.

Polyelectrolyte multilayer (PEM) films containing polycationic osmium (Os) bipyridyl (bpy) complex-attached poly(4-vinylpyridine) (PVP) derivative [Os(bpy)(2)Cl](2+)-PVP (Os-PVP) and polyanionic calf thymus DNA (CT-DNA) on the surface of gold (Au) electrodes were prepared using a layer-by-layer self-assembly method, and their redox properties were studied. Os complex shows different redox behavior with CT-DNA film in comparison with other PEM film which is composed of ordinary polymers. A cyclic voltammetric study suggested that the outermost polyanionic DNA layer does not hinder the redox reaction of Os complex within the Os-PVP/CT-DNA multilayer film, which may be helpful to understand the electron transfer mechanism with the DNA film. For all the Os-complex-containing PEM layers studied, a diffusion-free electron transfer from the Os complex moieties in these films to the electrode surface was observed. An electrocatalytic oxidation of ascorbic acid (AA) by this DNA-containing PEM film-covered electrode was also proposed.

2,2'-Dipyridyl↗
PubMed2004

Polyelectrolyte multilayer films with pegylated polypeptides as a new type of anti-microbial protection for biomaterials.

Adhesion of bacteria at the surface of implanted materials is the first step in microbial infection, leading to post-surgical complications. In order to reduce this adhesion, we show that poly(L-lysine)/poly(L-glutamic acid) (PLL/PGA) multilayers ending by several PLL/PGA-g-PEG bilayers can be used, PGA-g-PEG corresponding to PGA grafted by poly(ethylene glycol). Streaming potential and quartz crystal microbalance-dissipation measurements were used to characterize the buildup of these films. The multilayer films terminated by PGA and PGA-g-PEG were found to adsorb an extremely small amount of serum proteins as compared to a bare silica surface but the PGA ending films do not reduce bacterial adhesion. On the other hand, the adhesion of Escherichia coli bacteria is reduced by 72% on films ending by one (PLL/PGA-g-PEG) bilayer and by 92% for films ending by three (PLL/PGA-g-PEG) bilayers compared to bare substrate. Thus, our results show the ability of PGA-g-PEG to be inserted into multilayer films and to drastically reduce both protein adsorption and bacterial adhesion. This kind of anti-adhesive films represents a new and very simple method to coat any type of biomaterials for protection against bacterial adhesion and therefore limiting its pathological consequences.

Adsorption↗