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 1,657 records · Page 92Linked to original sources
PubMed2003

[Study on preparation of lanthanum-doped TiO2 nanometer thin film materials and its photocatalytic activity].

In this paper, lanthanum-doped TiO2 nanometer film materials coated on glass were prepared in Ti(OBu)4 precursor solutions by sol-gel processing. Transmittance and photocatalytic activity were respectively investigated and tested for these nanometer thin films prepared with different amount of lanthanum (La), different amount of polyethylene glycol (PEG), and different coating layer times. Some reactive mechanisms were also discussed. For one layer La-addition had little effect on the film transmissivity; but the photocatalytic activity was significantly improved due to La-addition. With increasing PEG, the transmittance of the film decreased for one layer film; but its photocatalytic activity did not rise. Increasing layer number did not affect the transmissivity of multilayer film. After coating two times, increasing layer number did not significantly improve the photocatalytic activity. The highest photocatalytic activity and best transmissivity were obtained for two layer TiO2 film when the dosage of lanthanum was 0.5 g and the dosage of polyethylene was 0.2 g in the precursor solutions. These materials will probably be used in the protection of environment, waste water treatment, and air purification.

Catalysis↗
PubMedDate not supplied

[Photovoltaic behavior of chlorophyll a and beta-carotene in Langmuir films].

The photovoltaic properties of chlorophyll a and beta-carotene Langmuir films and Langmuir films of a mixure of chlorophyll a and beta-carotene at different molar ratios were investigated. SnO2-optically transparent electrodes were used as a support. It was shown that the film photovoltage value depends on surface pressure and the total film thickness (the number of layers deposited onto SnO2-optically transparent electrodes). Fifteen layers (SP = 35 mH/m) of chlorophyll and 7-10 layers (SP = 20 mH/m) of beta-carotene give rise to a maximal photovoltage of 140 and 270 mV (at a shunt resistance of 10(7) Ohm), correspondingly. It was found that the photovoltage values in films of the carotene-chlorophyll mixture increase with the carotene concentration. The photovoltage value of a film containing 80-90% of carotene exceeds that of single-component pigment films prepared under the same deposition conditions.

Alkanes↗
PubMedDate not supplied

Study of optical transmittance of AgOx nano thin film in super-resolution near-field structure.

The AgOx-type super-resolution near-field structure (super-RENS) is one of the nano thin films that can give a nonlinear optical effect similar to that of the optical probe of the scanning near-field optical microscope. Structural variations of different thicknesses of the AgOx thin film are observed and studied using a field-emission scanning electron microscope (FE-SEM). For single AgOx nano thin film, the critical temperature and threshold of the evaporation temperature are 154 degrees and 600 degrees, respectively. Results show that the sandwiched AgOx nano thin film has a higher critical temperature, that is, about 280 degrees. For the sandwiched AgOx nano thin film, the transmittance peak is dependent on the thickness of the AgOx thin film. The interesting properties of the AgOx nano thin film of the super-resolution structure indicate a great potential for photonic applications.

Journal Article↗
PubMed2005

In vitro cytotoxicity of amorphous carbon films.

Amorphous carbon (a-C), carbon nitride (a-CN) and titanium films were deposited on stainless steel substrates (SS) using a dc magnetron sputtering system attached to a high vacuum chamber. Films were deposited using a base pressure of 1.3x10(-4) Pa. For the carbon films a pure graphite target was eroded in an Argon plasma. For the case of the a-CN films, the Ar flux was substituted by 100% N2 gas. Titanium films were deposited in a different chamber, using a pure Ti target and an argon plasma. In vitro studies were carried out on the coated samples using human osteoblasts cells. Cytotoxicity of carbon films was assessed by cellular adhesion and proliferation, as determined by direct cellular counting using a spectroscopic technique and a well-defined standard curve. Osteoblasts cells were also grown on uncoated steel and prepared Petri dishes for comparison. The percentage of osteoblasts adhesion measured at 24 hrs attained maximum values for the a-C films. Similarly, cellular proliferation evaluated at three, five and seven days showed an outstanding increase of osteoblasts cells for the a-C and Ti coatings in contrast to the uncoated steel. The cell functionality was evaluated by the MTT test after incubation periods of 3, 5 and 7 days. The absorbance values obtained for a-C, a-CN and Ti surfaces resulted significantly higher with respect to the positive control, indicating that the surface did not induce any toxic effect. Preliminary bio-mineralization was evaluated by measuring the elemental composition of the mineral grown on the substrates after periods up to 14 days.

Bone Substitutes↗
PubMed2005

Influences of emotion on context memory while viewing film clips.

Participants listened to words while viewing film clips (audio off). Film clips were classified as neutral, positively valenced, negatively valenced, and arousing. Memory was assessed in three ways: recall of film content, recall of words, and context recognition. In the context recognition test, participants were presented a word and determined which film clip was showing when the word was originally presented. In two experiments, context memory performance was disrupted when words were presented during negatively valenced film clips, whereas it was enhanced when words were presented during arousing film clips. Free recall of words presented during the negatively valenced films was also disrupted. These findings suggest multiple influences of emotion on memory performance.

Adult↗
PubMed2006

[Konjac glucomannan-collagen -chitosan blend films (I)].

Konjac glucomannan-collagen-chitosan blend films were prepared successfully by the solvent-casting method and were characterized by FT-IR,X-ray diffraction, SEM and optical transmittance. Moreover, tensile strength, breaking extension, water absorption, water vapor permeation coefficients, adsorbability and penetrating rates were measured. The results indicated that some strong interaction and good compatibility existed among Konjac glucomannan /collagen and chitosan in the blend films. Some properties of the KCCS films were improved markedly in comparison with binary blend films or Konjac glucomannan, collagen and chitosan film. The results of culturing vessel endothelial cells on CKCS-5 film showed that the blend films have good cell compatibility which indicates the potential for a scalfold material in tissue engineering.

Biocompatible Materials↗
PubMed2006

Film thickness and rheological properties of luting agents for crown cementation.

The film thickness and rheological properties [viscosity and tan sigma], of different resin based crown and bridge luting agents, including Panavia 21, Superbond, All Bond C&B Cement, Variolink were compared with zinc phosphate cement. A modification of the method in ISO 9917 (1991) and a controlled stress rheometer were used to monitor the changes in the film thickness and rheological properties respectively. For each material, the film thickness and rheological characteristics were determined at 60s after start of mixing and then made at regular intervals until immediately before the material was set. For the initial film thickness, the difference among the values for Varionk, Superbond and zinc phosphate cement was not significant (P>0.05), and less than 25microm. The values for All Bond C&B Cement and Panavia 21 were at least twice that of the other materials tested. All Bond C&B Cement produced the highest film thickness value at both the initial period and at 240s. Regarding viscosity, Superbond had the lowest initial value but the highest value at 240s. Variolink gave the highest initial value of viscosity, but the differences in the initial values among the other materials were small. During the whole period of testing, zinc phosphate cement gave the highest values of tan sigma, and Panavia 21 showed no significant change in any of the measured properties. The methods were able to distinguish the behaviour of different cement materials. Some resin cements produce larger than optimal values of film thickness and in some cases this is related to a rapid increase in viscosity after mixing. It is expected that differences in the ability of cements to form thin films will affect the seating of cemented restorations.

Analysis of Variance↗
PubMed2006

[Application of monoclonal antibody immobilized polyurethane film for site-specific gene therapy].

OBJECTIVE: To study the feasibility of delivering viral gene vector from a collagen-coated polyurethane (PU) film through a mechanism involving monoclonal antiviral antibody tethering. METHODS: Anti-adenoviral monoclonal antibodies were covalently bound to the collagen-coated PU surface. These antibodies enabled tethering of replication defective adenoviruses through highly specific antigen-antibody affinity. The PU film-based gene delivery using antibody-tethered adenovirus encoding green fluorescent protein (GEP) was tested in rat arterial smooth muscle cell (A10 cell) culture in vitro. The virus binding stability was studied by incubating the collagen-coated PU film in PBS solution at 37 degrees C for 20 days, followed with A10 cell cultures with the incubated films and the corresponding buffer solution. RESULTS: PU films with antibody-tethered adenovirus encoding GFP demonstrated efficient and highly localized gene delivery to A10 cells. Virus binding was stable for at least 10 days at physiological conditions, more than 77% of the originally bound virus remained in the film after 15 day's incubation. CONCLUSION: Gene delivery using PU film-based anti-viral antibody tethering of vectors exhibited potentials of applications in a wide array of single or multiple therapeutic gene strategies, and in further stent-based gene delivery therapeutic strategies.

Adenoviridae↗
PubMed1989

Densitometric evaluation of intra-oral radiographic film-processing solution combinations.

In order to determine the effect of seven film processing solutions on the quality of the radiographic image produced on three intra-oral speed group D radiographic films, an aluminium step-wedge was used as a phantom and the films exposed under standardized conditions. Processing was carried out, using each of the seven processing solutions in strict accordance with the manufacturers' recommendations. The processed films were subsequently subjected to densitometric evaluation and the data pertaining to base plus fog, radiographic contrast, density and relative film speed, for each film-processing solution combination, were tabulated. The best combination proved to be that of Flow X-ray film and Kolchem processing solution.

Densitometry↗
PubMed1995

Role of the post-lens tear film in the mechanism of inferior arcuate staining with ultrathin hydrogel lenses.

We studied the depletion of the post-lens tear film as contributing to inferior arcuate staining with ultrathin high water content hydrogel lenses. We monitored the post-lens tear film specular reflection of hydrogel lenses (0.04 mm center thickness, 67% nominal water content), which caused inferior arcuate staining. A standard thickness (0.12 mm) lens was worn in the contralateral eye as a control condition. Lenses were worn for a 2 hour period by 20 subjects. Post-lens tear film appearances were categorized as amorphous, faint colored, or colored, where the colored patterns represented a relatively depleted post-lens tear film. We also measured lens dehydration, lens adherence, and pre-lens tear film stability in order to evaluate their role in inferior arcuate staining. The ultrathin and standard lenses caused staining in 100 and 75% of subjects, respectively; the severity of staining was much greater with the ultrathin lenses (Wilcoxon signed ranks test, P = 0.0004). The ultrathin lenses were associated with a higher incidence of post-lens tear film depletion (P = 0.018), had greater front surface dehydration (P = 0.0004), and were more adherent to the eye (paired t-test, P = 0.001). However, pre-lens tear thinning times were not significantly different between the two lens types (Wilcoxon signed ranks test, P > 0.05). These findings support the contention that post-lens tear film depletion is a component of a lens adherence or lens dehydration mediated mechanism of inferior arcuate staining.

Adult↗
PubMed1995

[Efficacy of abdominal plain film and CT in bowel obstruction].

The studies of 106 patients who underwent both plain film and CT studies in the course of assessment for suspected bowel obstruction were subjected to a blinded retrospective analysis. Plain film and CT scans were divided into six groups on the basis of bowel gas pattern (within normal limits = WNL, non-obstructive ileus = NOI, small bowel obstruction suspected = SBOs, small bowel obstruction definite = SBOd, large bowel obstruction suspected = LBOs, large bowel obstruction definite = LBOd), and a comparison was made with the surgically and/or clinically proved diagnosis. Overall sensitivity was 71.7% on plain film and 83.0% on CT. The positive predictive value of SBO was 80.3% on plain film, 95.1% on CT. The false negative ratio in small bowel obstruction was 8.2% on plain film, but only 1.6% on CT. Half of the cases (50.8%) that were read as SBOs on plain film were "definite" on CT. Causes of obstruction and abnormalities other than bowel lesion were more often detected by CT. The author stresses that a plain film study should initially be carried out in bowel obstruction and that, by adding CT as a subsequent examination, diagnosis becomes more definite.

Adult↗
PubMed1994

[Diagnosis of metastases in thoracic images. Progress by further development of the conventional film-foil technique?].

In addition to digital radiography and AMBER, the development of asymmetric screen-film systems is another attempt to optimize chest radiography. Due to reduced contrast in the parenchyma, the former asymmetric screen-film systems did not show sufficient image quality. Three new asymmetric systems with completely different composition are available now. In-Sight VHC (Kodak), High Light GUV (3M) and Opthos D (Agfa) were compared to standard chest films using densitometric curves, a chest phantom for high and low contrast detectability, a nodule detection phantom and patient studies. The sensitivity of nodule detection in the mediastinum has been 41-48% for L-films and 58-65% for the asymmetric screen-film systems. No differences could be demonstrated for nodule detection in the lung field. Contrast in the parenchyma is equivalent to L-films. There is no loss of diagnostic information in the lung field. Differences between the asymmetric systems concern speed, dynamic range and granularity. If AMBER and digital radiography are not available, new asymmetric screen-film systems can improve nodule detection without further investment costs.

Humans↗
PubMed1997

Assessment of the tear film with tandem scanning confocal microscopy.

PURPOSE: To evaluate the confocal microscopic appearance of the tear film by correlating the interference pattern created by the lipid surface with physiologic measurements of tear function and with clinic diagnosis. METHODS: A series of 53 patients was examined with a battery of tests to evaluate the tear film and with confocal microscopy to evaluate the interference pattern created by the lipid surface of the tear film. Assessment of the tear-film appearance involved five nonparametric scales: degree of debris in the tear film, variability of the interference pattern over time, linearity of the interference pattern, number of dry spots seen, and relative thickness of the lipid layer. For 10 other subjects, the confocal appearance of the tear film and evaporation from the ocular surface was tested for before and after meibomian gland expression. RESULTS: The confocal appearance correlated with multiple physiologic variables and clinical diagnosis. Patients with seborrheic meiboman gland dysfunction had a thicker lipid layer, greater variability, and more debris than did patients with obstructive meibomiam gland dysfunction. After meibomian gland expression, lipid thickness and linearity increased, whereas pattern variability and evaporation decreased significantly. The mean reduction in evaporation was 48%. CONCLUSIONS: Confocal microscopy can be used to examine the tear film, and its appearance correlates significantly with physiologic variables in normal-individuals and in disease states. The confocal appearance of the lipid interference patterns and evaporation from the ocular surface are altered after lipid expression from meibomian glands.

Adolescent↗
PubMed1997

The effects of time and light exposure on contact and pressure measurements using Fuji prescale film.

The search for methods to demonstrate and accurately measure contact area and pressure within human joints has been and remains an active one. Presenssor is a measuring system developed by Fuji Photo Film Co., Ltd. and used in medical applications. The color intensity fades with time and exposure to light. These changes have not been well documented despite the increasing use of Fuji film in biomedical research. These changes in color intensity provide a source of error in the calculated measurements. The known variability of the color density of film exposed to light and air can be measured and predicted. Methods to control and improve the accuracy and reliability of study data are suggested. Film was exposed to three different amounts of pressure and placed into one of four subgroups: exposed to light and taped or not taped, and stored in the dark and taped or not taped. Fading of the color density was seen after only a few hours of exposure to light when the film was left untaped. When the film was taped, a slight darkening was seen. For the best accuracy and reliability, the film should be digitized or analyzed within eight hours of exposure to pressure.

Bias↗
PubMed1997

[Comparison of film-screen combinations with contrast detail diagram and interactive image analysis. 2: Linear assessment of grey scale ranges with interactive image analysis].

The following three screen-film combinations were compared: a) a combination of anticrossover film and UV-light emitting screens, b) a combination of blue-light emitting screens and film, and c) a conventional green fluorescing screen-film combination. Radiographs of a specially designed plexiglass phantom (0.2 x 0.2 x 0.12 m3) with bar patterns of lead and plaster and of air, respectively were obtained using the following parameters: 12 pulse generator, 0.6 mm focus size, 4.7 mm aluminum pre-filter, a grid with 40 lines/cm (12:1) and a focus-detector distance of 1.15 m. Image analysis was performed using an IBAS system and a Zeiss Kontron computer. Display conditions were the following: display distance 0.12 m, a vario film objective 35/70 (Zeiss), a video camera tube with a PbO photocathode, 625 lines (Siemens Heimann), an IBAS image matrix of 512 x 512 pixels with a resolution of 7 lines/mm, the projected matrix area was 5000 microns2. Grey scale ranges were measured on a line perpendicular to the grouped bar patterns. The difference between the maximum and minimum density value served as signal. The spatial resolution of the detector system was measured when the signal value was three times higher than the standard deviation of the means of multiple density measurements. The results showed considerable advantages of the two new screen-film combinations as compared to the conventional screen-film combination. The result was contradictory to the findings with pure visual assessment of thresholds (part I) that had found no differences. The authors concluded that (automatic) interactive image analysis algorithms serve as an objective measure and are specifically advantageous when small differences in image quality are to be evaluated.

Algorithms↗
PubMed1997

Preparation and characterization of antibacterial alginate film containing DNA as a carrier of silver ion.

Silver ion was effectively bound to alginate film by the aid of DNA. Amounts of Ag(I) bound to the films (18 mm x 18 mm) were 4.2 micrograms and 24.7 micrograms in the absence and presence of DNA, respectively. The Ag(I)-induced films showed antibacterial activity for both of Escherichiacoli (E. coli) and Staphylococcus aureus (S. aureus), and the activity of DNA-alginate film was obviously larger than alginate film. These results indicate that Ag(I) induced in the DNA-alginate film keeps the potent antibacterial activity, and so DNA is very useful as a carrier of silver ion in the alginate film.

Alginates↗
PubMed1976

Direct recording on rectilinear scan images on 4x5-in. film.

Rectilinear scans are usually recorded on 14 X 17-in. x-ray film. This is costly both in terms of film and storage space. Using 4 X 5-in. film instead of the larger film will reduce this cost. An Ohio-Nuclear Model 84FD dual-probe 5-in. scanner was converted for the production of scan images directly on 4 X 5-in film (Kodak SO-79 nuclear medicine film). The smaller images may be viewed directly on a standard x-ray viewbox, or they may be projected if a larger image is desired. The image quality is excellent. This system has replaced the 14 X 17-in. film at our institution.

Photography↗
PubMed2006

Dose and energy dependence of response of Gafchromic XR-QA film for kilovoltage x-ray beams.

There is a growing interest in Gafchromic films for patient dosimetry in radiotherapy and in radiology. A new model (XR-QA) with high sensitivity to low dose was tested in this study. The response of the film to different x-ray beam energies (range 28-145 kVp with various filtrations, dose range 0-100 mGy) and to visible light was investigated, together with the after exposure darkening properties. Exposed films were digitized with a commercially available, optical flatbed scanner. A single functional form for dose versus net pixel value variation has been determined for all the obtained calibration curves, with a unique fit parameter different for each of the used x-ray beams. The film response was dependent on beam energy, with higher colour variations for the beams in the range 80-140 kVp. Different sources of uncertainties in dose measurements, governed by the digitalization process, the film response uniformity and the calibration curve fit procedure, have been considered. The overall one-sigma dose measurement uncertainty depended on the beam energy and decreased with increasing absorbed dose. For doses above 10 mGy and beam energies in the range 80-140 kVp the total uncertainty was less than 5%, whereas for the 28 kVp beam the total uncertainty at 10 mGy was about 10%. The post-exposure colour variation was not negligible in the first 24 h after the exposure, with a consequent increase in the calculated dose of about 10%. Results of the analysis of the sensitivity to visible light indicated that a short exposure of this film to ambient and scanner light during the measurements will not have a significant impact on the radiation dosimetry.

Calibration↗