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PubMed1998

The medical film 1897-1997: Part I. The first half-century.

Medicine has frequently been in the forefront of applying new illustrative media to its needs, and cinematographic film is a good example. Within a year of the introduction of moving pictures, cine-film was used for medical research and to a lesser extent for teaching. The profession took advantage of the spread of cinemas by making health education films, and during the first half century of cinematography surgeons were keen to have their operations filmed. Medical educators were slow to include film in their teaching programmes and several organizations were formed to encourage their use. After the Second World War, medical films for undergraduate and postgraduate education became accepted until, as the medical film reached its centenary, cine-film declined in favour of video-recordings.

Education, Medical↗
PubMed1995

Film oxygen transmission rate effects on ground chicken meat quality.

Effects of the packaging film oxygen transmission rate (OTR) on the odor, color, aerobic plate count, and cooked volatile compounds in ground chicken leg meat were evaluated over a 14-d refrigerated storage (4 C) period. Freshly desinewed and ground chicken leg meat was packaged under minimal vacuum in five films of different OTR. Films ranged from 30 to 12,000 mL oxygen/m2 per 24 h. Odor scores of meat in packages opened after 10 d were lower for the lowest OTR film than films with higher OTR. Aerobic plate counts increased at a faster rate in the higher OTR films, and cooked meat volatile profiles showed little variation due to OTR film type. Specific products will require different packaging to optimize shelf-life quality. For ground chicken leg meat, an intermediate OTR film is best to maintain a majority of the quality attributes during refrigerated storage.

Analysis of Variance↗
PubMedDate not supplied

The effect of tear film on higher order corrections applied to the corneal surface during wavefront-guided refractive surgery.

PURPOSE: To investigate whether the property of the surface of a fluid film to smooth irregularities in the underlying surface will cause the tear film to partially erase the effect of higher order corrections ablated onto a corneal surface during wavefront-guided refractive surgical correction. METHODS: Coating flow theory shows that the film surface initially replicates the underlying surface. An iteration method is given to allow calculations to be made of the tear fluid flow and resulting surface change during the time between blinks. A new experimental technique is introduced using a corneal topographer and live video imaging to observe changes in tear surface curvature as the tear film flows. RESULTS: Tear flow changes in an eye with a high amount of aberration due to an unsuccessful LASIK procedure are simulated to show that while tear fluid occurs and causes changes in the tear/air surface, the change when expressed in terms of unwanted aberrations is below that which would cause any image degradation. Results of the live video technique on a cornea with an irregular surface 4 days after photorefractive keratectomy show that irregularities in the tear film surface immediately after a blink are not smoothed to any extent in the time before the next blink. CONCLUSIONS: Tear film flow following initial film formation by a blink can be demonstrated by computer simulation and observed with live corneal topography video. Tear film dynamics will not erase the effects of ablative corrections for higher order aberrations.

Blinking↗
PubMed1999

[Analysis of the oxide film of Ni-Cr porcelain alloy].

OBJECTIVE: In order to find out the causes of cervical gray line of PFM crown, the features of oxide film of Ni-Cr alloy were investigated. METHODS: 1. The phases were analyzed using x-ray radiation shield. 2. Compositions of oxide film and base metal were measured using electronic scanning microscope. 3. The thickness of oxide film and the variations of Ni, Cr, O in oxide film were evaluated using Auger electron spectroscope. RESULTS: 1. There were not only NiCr2O4 but also Cr2O3, SiO2, and gamma phase solid solution in the surface. 2. The weight contents of Cr and Si were higher while Ni was lower in oxide film than in the base. 3. Oxide film became much thicker(400 nm: 16 nm) after the temperature cycling. CONCLUSION: The medium-thicked oxide film was formed after baking, and it was not a complete film.

Chromium Alloys↗
PubMed2002

[Tear film changes after phacoemulsification].

OBJECTIVE: To evaluate tear film changes after phacoemulsification. METHODS: This prospective randomized study involved 68 consecutive patients with age-related cataract (79 eyes) who underwent phacoemulsification. Tear break-up time, Schirmer I test (S I t) value, corneal fluorescein staining, tear film pattern by DR-1 tear interfermetry and the height of tear meniscus were measured preoperatively and 1 day and 2, 7, 14, 30, 180 days postoperatively. RESULTS: At 1 day and 2 days postoperatively, the mean tear break-up time reduced greatly, and the number of patients who showed III to V tear film pattern, the mean S I t value, the height of tear meniscus and fluorescein staining scores increased significantly (P < 0.001 for day 1, P < 0.005 for day 2). S I t value at 7 days postoperatively (P = 0.831) and the height of tear meniscus at 14 days returned to their preoperative values (P = 1.000). The tear break-up time, corneal fluorescein staining scores and the grades of tear film pattern all recovered at 30 days postoperatively (P > 0.05). At 30 days postoperatively, 19.3% of patients showed shorter tear break-up time and less S I t value than that of preoperative day. In addition, 1/9 of the patients with normal preoperative tear film experienced dry eye at 30 days postoperatively. The cases with tear break-up time < 10 seconds compared to patients with tear break-up time >/= 10 seconds were more easily to show tear instability postoperatively (relative risk 13.5, 8.25, 20.0, 39.0, 8.6, 3.9 at 1 day and 2, 7, 14, 30, 180 postoperative days, respectively). CONCLUSION: Phacoemulsification significantly alters the tear break-up time, S I t value, corneal fluorescein staining, tear film pattern and the height of tear meniscus. Some patients with normal tear film may experience dry eye after surgery. Patients with preexisting tear break-up time < 10 seconds are easily at risk of experiencing the tear film instability postoperatively.

Aged↗
PubMed2000

[Determination of the composition distribution of polymer blend films by using microscopic FTIR].

In this paper, PS/PC blend film (about 120 microns thick) and PS/PMMA (about 90 microns thick) blend film were prepared by evaporation the solvent very slowly from polymer blend solution. Different FTIR methods were used to determine the composition distribution along the vertical direction of the films. PS/PC film was firstly sectioned by ultramicrotomy, then the vertical section was measured to determine the composition of every 16 microns width unit from the surface-side to the bottom-side by Microscopic transmission-FTIR. The results showed that the concentration of PS was significantly greater in the vicinity of the surface of the film than that in the bulk, i.e., the component of PS enriched to the surface. Focusing the reflecting infrared light on different layer of the film, we can detect the composition of the different depth region in the PS/PMMA blend film. As the result, PMMA aggregated to the bottom of the film. It was considered that this effect was related to the different affinity and wetting prosperities of the blend component to the substrate or air.

English Abstract↗
PubMed2003

Accessing the living laboratory: trigger films as an aid to developing, enabling, and assessing anesthesia clinical instructors.

Problems arise when clinical instructors are placed in situations for which they are ill prepared. Teaching occurs in settings where patient safety and quality must be ensured. Trigger films are 2- to 4-minute vignettes simulating real-life situations that finish abruptly, stimulating participants to analyze situations in a safe environment. This study's purpose was to develop and assess the validity of high fidelity trigger films in facilitating nurse anesthesia clinical instructor development. Trigger films were produced in our simulation laboratory involving: (1) the overly confident student, (2) the self-defeating student, and (3) teaching stressed by production pressure. Trigger films consisted of Part A, the introduction of a complex teaching situation, and Part B, offering 1 possible resolution. Trigger films attained validity using a national panel of experts (kappa > 0.88, all indices). Seventy-four clinical instructors viewed trigger films, completing an extensive evaluation. Scenario themes were consistently described; the depicted, desirable clinical instructor attributes were routinely identified by the participants. This study initiated the process of demonstrating validity and reliability of trigger films in this setting. Trigger films may offer a systematic approach to facilitating clinical instructor development by safely engaging clinical instructors in a range of complex scenarios in the "living laboratory." They may have application in other healthcare domains as well.

Clinical Competence↗
PubMed2004

[Effect of oxygen partial pressure on the band-gap of the TiO2 films prepared by DC reactive sputtering].

TiO2 films have been deposited on glass substrates using DC reactive magnetron sputtering at different oxygen partial pressures from 0.10 to 0.65 Pa. The photoluminescence (PL) spectra of the films were recorded. The results of the PL spectra showed that there were three emission peaks at 370, 472 and 514 nm for the films sputtered at 0.35 and 0.65 Pa, and there were two peaks at 370 and 490 nm for the films sputtered at 0.10 and 0.15 Pa. The band-gap for the films was 3.35 eV. For the films sputtered at 0.35 and 0.65 Pa there were two defect energy levels at 2.63 and 2.41 eV, corresponding to 0.72 and 0.94 eV below conduction band for the band-gap, respectively. For the films sputtered at 0.10 and 0.15 Pa, there was an energy band formed between 3.12 and 2.06 eV, corresponding to 0.23 and 1.29 eV below the conduction band. With increasing the oxygen partial pressure, the defect energy band changed to two energy levels, and the energy levels nearly disappeared for the film sputtered at 0.65 Pa of oxygen partial pressure.

English Abstract↗
PubMed1992

Study of precorneal tear film thickness and structure by interferometry and confocal microscopy.

Past measurements of precorneal tear film thickness in rabbits and humans gave values of 4-7 microns. These have been the accepted values. However, measurements presented in this report are much higher. Earlier techniques may have changed film thickness or not have fully included the layer containing mucus. Little is known about the mucus component. Thickness was measured in freshly killed animals of 10 species using two independent optical techniques. Coherent light was reflected from eyes and thickness was determined from spacing of interference fringes. Clear images of tissue structure were obtained with confocal microscopy, the tear film was visually identified, and thickness measured. Measurements by the two methods were closely correlated in each animal. No film was detected in trout or carp. In other species, thickness ranged from 9 microns in frogs to 15 microns in gerbils. Values are significantly larger than earlier estimates. Film thickness in three living rabbits was not significantly different from that measured shortly after death. There was no variation in thickness at five positions across the cornea in three species. Mucus content of rat tear film was examined by measuring thinning after application of 4, 8, and 20% (weight/volume) acetylcysteine, a mucolytic agent. Thickness was considerably reduced compared to controls, and the film almost completely removed by the highest concentration. The authors propose that the film is largely composed of mucus, not free aqueous solution. Our methods include such layers, and measurements are correspondingly larger than earlier ones.

Animals↗
PubMed1992

Study of human precorneal tear film thickness and structure using laser interferometry.

The authors previously found that measurements of precorneal tear film thickness in animals, using laser interferometry and confocal microscopy, were larger than earlier estimates. They proposed that this occurred because optical methods did not disturb film structure and measured full thickness, including mucus. In the present study, tear film thickness was measured in humans. Coherent light was reflected from eyes and formed interference patterns. Thickness was determined from spacing of fringes. Mean thickness in six subjects was 34-45 microns, more than four times larger than earlier values. Validity and accuracy of measurements by interferometry were examined in our earlier study using confocal microscopy. Here it provided supportive evidence. Tear film thickness was estimated from optical sections through the corneas of three subjects to be 41-46 microns. Mucus content of the film also was examined. Interferometry was used to measure thinning after application of a mucolytic agent. There was no change in thickness after 5 min exposure to 0.1% (weight/volume) acetylcysteine. Solutions of 20% caused thinning to 11 microns, and thickness slowly increased to reach its original value over 40 min. Thus, the film seemed to be composed substantially of mucus, not aqueous fluid. The results also provided evidence that measurements by interferometry did not include underlying epithelium. Earlier nonoptical methods probably did not include the portion of the film that contained mucus. They seem to have greatly underestimated human tear film thickness.

Adult↗
PubMed2004

Sodium citrate cross-linked chitosan films: optimization as substitute for human/rat/rabbit epidermal sheets.

UNLABELLED: PURPOSE. To prepare chitosan films that shall be capable of simulating in vitro permeation of polar (5-FU) and non polar (indomethacin) drugs across rat/rabbit/human epidermis. METHOD: Statistical designs were utilized to identify the formulation and process variables that significantly influenced permeation of both drugs across chitosan films cross-linked with sodium citrate (Nacit). In addition, atomic absorption spectroscopy for Na+ and differential scanning calorimetry of these films were performed for understanding the cross-linking behaviour. RESULTS: Concentration of chitosan, cross-linking time and concentration of cross-linking agent significantly influenced the in vitro flux of both drugs. Na+ content in films cross-linked with Nacit solutions without adjustment of pH was found to increase whereas, DeltaH of cross-linking endothermic transition decreased. However, after dipping these films in phosphate buffer (pH 7.4) both Na+ and DeltaH was found to decrease. Such a decrease was not observed when films cross-linked with sodium citrate solutions after adjustment to pH 5 were dipped in phosphate buffer (pH 7.4). The in vitro permeation of both drugs across latter films was significantly less. CONCLUSION: Adjustment of Nacit solution pH to 5 produced ionic complexes that were resistant to alkaline pH. Chitosan films can be cross-linked with Nacit to simulate in vitro permeation of polar and non polar drugs across animal/human epidermis.

Animals↗
PubMed2005

[Preparation and infrared spectral analysis of nanoporous silica thin film].

Crack-free homogeneous nanoporous silica films on silicon wafer have been synthesized via supercritical drying of wet gel films obtained by spin-coating the polymeric silica sol, which was prepared using sol-gel method with tetraethoxysilane (TEOS) as precursor. The film is amorphous and nanoporous, and three-dimensional network, cross-linked by the primary particles whose sizes distribute between 10-20 nm showed respectively by XRD and SEM micrograph. The structure of the nanoporous SiO2 thin film was studied by FTIR spectra. The SiO2 thin film was composed of Si-O-Si and Si-OR, and was hydrophobic. The film contained Si-OH and became hydrophilic after being heat-treated at 250 degrees C or above in air. The heat-treated SiO2 thin film becomes hydrophobic by reacting with trimethylchlorosilane(TMCS). The TMCS-modified SiO2 thin film remains hydrophobic and can keep its nanoporous structure at a temperature lower than 450 degrees C in nitrogen.

Hot Temperature↗
PubMed1991

Observations of tear film break up on model eyes.

Models of the human eye's anterior surface were constructed from polymethylmethacrylate. Some models had a rigid gas permeable contact lens cemented to the corneal apex; others had strips of plastic or metal cemented at the location of the lids in the open human eye. When the level of water was lowered in the bath surrounding the upward-gazing eye model, tear film break up could be observed. Covering the model with mucin (from saliva) changed the pattern of tear film break up. On the mucin-covered model eye, the tear film break up resembled break up observed in the human eye. These studies on model eyes suggest that tear film break up occurs when tension in the tear film becomes greater than the tensile strength of the film. The mucin layer reduces the thickness of the tear film at break up and the thickness of the retreating film.

Contact Lenses↗
PubMed1990

[Influence of types and surface treatment of dental alloy and film thickness of cements on bond strength of dental luting cements].

The goal of this study was to test the influence of the type and oxidation treatment of dental casting alloys on the tensile bond strength of luting cements. Also, the influence of film thickness of luting cements on the tensile bond strength of different dental casting alloys was examined. Four different luting cements (zinc phosphate, polycarboxylate, glass ionomer and adhesive resin cements) and four different dental casting alloys (Au-Ag-Cu, Ag-Pd, hardened Ag-Pd and Ni-Cr alloys) were used. Cylindrical alloy rods for the tensile bond strength test were casted, and then, top surfaces of the rods were cemented with each luting cement to the bottom surfaces of other rods, using the film thickness adjustment apparatus. The film thickness of luting cement was adjusted to 20, 30, 50, 75 or 100 microns. The tensile bond strengths of each cement to different casting alloys at each film thickness were measured one day after the rods had been cemented. The tensile bond strength of the zinc phosphate cement could not be determined in this study due to the separation of the alloy rods cemented with the zinc phosphate cement in water before the tensile test. The tensile bond strength to the adhesive resin cement to any alloy showed the greatest strength; however, that of the glass ionomer cement to any alloy was the lowest strength among the cements examined. The Ni-Cr alloy had the highest bond strength of any luting cement, compared to other alloys. The tensile bond strengths of luting cements significantly decreased with the increase in film thickness of cement layer. The adhesive resin cement had the greatest bond strength, and the glass ionomer cement was the lowest bond strength at any film thickness. The oxidation treatment significantly increased the bond strength of the adhesive resin cement to both Au-Ag-Cu and Ag-Pd alloys. The tensile bond strength of the adhesive resin cement was most dependent upon the film thickness of cement layer, and that of the polycarboxylate cement was least dependent upon the film thickness of cement layer among the cements examined. In addition, the oxidation treatment for precious alloys could be a factor contributing to the increase in the bond strength of the adhesive resin cement.

Adhesiveness↗
PubMed1987

Recent advances in screen-film mammography.

Today there are many dedicated mammographic x-ray units available that are capable of providing high-quality screen-film mammograms. Likewise, screen-film combinations designed for mammography are capable of providing images with appropriate contrast, resolution, and noise levels. Proper film processing is most important in order to obtain the appropriate film speed and contrast. A higher-speed screen-film combination designed for mammography can provide mammograms with significantly lower radiation dose, especially for grid and magnification techniques. Designing x-ray units and techniques as well as screen-film combinations with the singular goal of reducing radiation dose will always involve compromises and trade-offs. The key is to always consider optimizing all of the factors that affect image quality: (1) appropriate beam quality, (2) breast compression, (3) consideration of the use of grids, (4) good geometry, (5) selection of an appropriate screen-film combination, and (6) proper film processing. Optimization of all appropriate imaging factors will produce high-quality mammograms at the lowest radiation dose to the patient.

Female↗
PubMed1973

A film program in a teaching hospital.

The Martland Hospital Medical Library has for more than a year been conducting a 16mm film program for interns, residents, attending physicians, and nurses as an adjunct to continuing education. It was possible to run this project on a minimal budget because many films are available at little or no cost from governmental agencies, pharmaceutical companies, medical associations, and universities. The program is run on a departmental basis. Films for a department are selected by the chief resident in that department from a list which the librarian has prepared of available films in the specialty involved. The library orders and publicizes the films and transacts all business in connection with them. Films pertinent to clinical practice are preferred. The administration of this program is described in this paper, and a number of film catalogs are evaluated. Criteria for film selection are discussed.

Education, Medical, Continuing↗
PubMed1993

[The diagnosis of malaria by the thick film and the QBC: a comparative study of both technics].

BACKGROUND: The diagnosis of paludism is important because of the severity of the clinical picture caused by Plasmodium falciparum, the increasing number of travellers to endemic zones and the emigration from these zones. A comparative study of the QBC techniques (staining with acridin orange and observation with ultraviolet light) and the thick film with Giemsa staining was carried out. METHODS: The QBC and thick film were performed parallelly for 17 months in a total of 623 samples pertaining to subjects from endemic zones of paludism (emigrants, immigrants and travellers). RESULTS: Of the 623 samples studied 49 were positive for paludism by both techniques. Ten were positive with only the thick film and six were positive only with QBC. The sensitivity of QBC versus thick film was 83% and specificity 98.9%. The time used to determine diagnosis with the QBC technique ranged from 6 to 12 minutes from withdrawal of the sample, while with the thick film the time spent was more than 2 hours. The cases positive by thick film and negative with QBC corresponded to patients with very low parasitation. The intensity of parasitation was difficult to determine quantitatively by QBC. CONCLUSIONS: Although the QBC technique has the advantage of speed it is inexact with respect to the quantification of parasitemia. Moreover, it is less sensitive than the thick film in patient with very low parasitations and cannot thus substitute the thick film.

Africa↗
PubMed2006

Portal verification of high-energy electron beams using their photon contamination by film-cassette systems.

BACKGROUND AND PURPOSE: Though electron beams are widely used in radiotherapy, their verification is not well established in clinical practice. The present study compares the suitability of several sensitive film-cassette systems for electron-portal verification by contaminating photons. MATERIAL AND METHODS: The characteristics of the optical density curves of film-cassette combinations were determined by exposing them to the bremsstrahlung contamination of a variety of electron beams. Using a Las-Vegas Phantom the spatial low-contrast resolution of the combinations was investigated. The absorbed dose rates due to the contaminant photons were measured for different geometric conditions. RESULTS: Suitable film-cassette combinations were found for portal verification of all usual electron energies. The best image quality was obtained using the EC film and the EC-L cassettes. For electron energies higher than 6 MeV some film-cassette combinations are suitable to verify abutted electron and photon portals using the same film sheet. CONCLUSION: The verification of electron portals and of abutted electron-photon portals can be performed by sensitive film-cassette systems with an image quality comparable to photon-beam verification.

Densitometry↗