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PubMed1998

Selectively Swollen Films of Triblock/Diblock Copolymer Blends: Dependence of Swollen Film Structure on Blend Composition.

Compositional variation in blends of triblock and diblock copolymer films can be used to adjust the film response to a selective solvent. We investigated the relationship between blend composition and film structure in ordered films containing poly(styrene-b-2-vinylpyridine) (PS-P2VP) diblocks and PS-P2VP-PS triblocks. The study focuses on films possessing a lamellar morphology. Methanol, a strongly selective solvent for P2VP, is used to swell the films. Since methanol solvates P2VP but not PS, periodic multilayer structures result in which solvent-rich P2VP domains are separated by undissolved PS domains. The film structure is characterized in the dry and swollen states with neutron reflectivity. Although the dry state morphology dimensions are practically identical for all samples, in the swollen state films richer in triblock swell less due to higher density of bridges interconnecting the PS domains. Furthermore, in swollen triblock-containing samples, polymer concentration variations in P2VP domains are suppressed and the PS domains are better aligned with respect to the substrate.

Journal Article↗

PubMed2001

Integration of microfabricated needle-type glucose sensor devices with a novel thin-film Ag/AgCl electrode and plasma-polymerized thin film: mass production techniques.

We developed an integrated array of needle-type biosensors employing a novel process of fabrication, comprising conventional semiconductor fabrication and micromachining technology. Amperometric sensing electrodes with plasma-polymerized films and a thin-film Ag/AgCl reference electrode were directly integrated on a glass substrate with thin-film process, e.g., sputtering. An enzyme was immobilized on the electrode via the plasma-polymerized film, which was deposited directly on the substrate using a dry process. The novel thin-film Ag/AgCl reference electrode showed stable potentials in concentrated chloride solutions for a long period. The plasma-polymerized film is considered to play an important role as an interfacial design between the sensing electrode and the immobilized enzyme considering that the film is extremely thin, adheres well to the substrate (electrode) and has a highly cross-linked network structure and functional groups, such as amino groups. The results showed increments of the sensor signal, probably because the plasma-polymerized film allowed a large amount of enzyme to be immobilized. The greatest advantage is that the process can permit the mass production of high-quality biosensors at a low cost.

Biosensing Techniques↗

PubMed1976

[Picture quality and film mammography. I. The physical parameters of the filming system (gradation, sensitivity, definition and granularity) and the effect of exposure geometry (author's transl)].

The physical parameters of three radiographic filming systems used for mammography were analysed (industrial film without screens, lo dose system (Dupont), industrial film with lo dose screens). Their effect on image quality was studied and the influence of the exposure geometry on sharpness and detail was investigated experimentally. Geometrical unsharpness so reduces the difference in definition between screenless industrial film and a film-screen combination that the total unsharpness at the centre of the breast parenchyma of an average breast becomes approximately the same. In particular, recognition of fine detail (microcalcification) is reduced by geometric unsharpness. Final grading of the three film systems is only possible after development of a concept of film quality which takes account of the parameters of the filming system and of exposlre geometry, together with physiological and practical requirements (paper II).

Absorptiometry, Photon↗

PubMed1976

Female responsiveness to erotic films and the "ideal" erotic film from a feminine perspective.

Subjects were 20 volunteers randomly selected from all female undergraduate students attending a local university, who were 21 years of age or older, and living off campus. The stimuli consisted of seven films, of approximately 5 minutes duration each, which depicted various types of human sexual behavior. Themes included "romantic" heterosexual behavior, primarily genital heterosexual behavior, a mild, and an explicit form of group-sex behavior, a mild and explicit form of heterosexual sadomasochistic behavior, and male homosexuality. Subjects rated the degree of sexual arousal experienced for each film on a 50-point Likert scale. The order of presentation of the films for each subject was randomized, and all subjects participated individually with only a female experimenter present. Following the rating period, subjects completed the Sex Knowledge and Attitude Test (9). Finally, a structured interview was conducted to probe specific likes and dislikes with respect to the content of the films viewed. Results indicated that rank order ratings of the films, from most to least sexually stimulating, was: heterosexual, romantic; group-sex mild (two males and one female); heterosexual-genital; group-sex explicit (three males and three females); sadomasochism (mild); sadomasochism-explicit (forcing and brutal); and male homosexuality. One conclusion that the data led to was that females preferred and were significantly more sexually stimulated by films in which a male related to a female (even if the male was treating the female cruelly) than they were by homosexual stimuli involving two males together. Correlational data between the rating responses and the Sex Knowledge and Attitude Test yielded much information including significant negative correlations between ratings of both group-sex films and rejection of sexual myths. Also, significant positive correlations were found between rated degree of sexual stimulation for the heterosexual and the group-sex films and the consideration of pre- and extramarital relations as acceptable or even desirable.

Abortion, Spontaneous↗

PubMed1995

Detection of simulated chest lesions: comparison of a conventional screen-film combination, an asymmetric screen-film system, and storage phosphor radiography.

PURPOSE: To compare a high-contrast asymmetric screen-film system with a conventional screen-film combination and storage phosphor radiographs for detection of simulated chest lesions. MATERIALS AND METHODS: To test the diagnostic performance of these three systems, the authors used three types of simulated lesions that were superimposed over the chests of 10 patients and an anthropomorphic phantom. In the patient and phantom study, a total of 1,350 observations by each of the eight radiologists were analyzed by means of receiver operating characteristics. RESULTS: In the patient study, mediastinal nodules were better visualized with high-contrast asymmetric screen-film and storage phosphor radiographs compared with the conventional screen-film system. For visualization of pulmonary nodules, the high-contrast asymmetric screen-film system was best. Micronodules were poorly visualized on high-contrast asymmetric screen-film and storage phosphor radiographs, but only in the phantom study. CONCLUSION: The high-contrast asymmetric screen-film system combines the advantages of conventional screen-film radiographs with improved visualization of the mediastinum.

Adult↗

PubMed2006

Immobilization of biomaterials to nano-assembled films (self-assembled monolayers, Langmuir-Blodgett films, and layer-by-layer assemblies) and their related functions.

For utilization of highly sophisticated functions of biomaterials in nano-scale functional systems, immobilization of biomaterials on artificial devices such as electrodes via thin film technology is one of the most powerful strategies. In this review, we focus on three major organic ultrathin films, self-assembled monolayers (SAM), Langmuir-Blodgett (LB) films, and layer-by-layer (LBL) assemblies, and from the viewpoints of biomaterial immobilization, typical examples and recent progresses in these film technologies are described. The SAM method allows facile contact between biomaterials and man-made devices, and well used for bio-related sensors. In addition, recent micro-fabrication techniques such as micro-contact printing and dip-pen nanolithography were successfully applied to preparation of biomaterial patterning. A monolayer at the air-water interface, which is a unit structure of LB films, provides a unique environment for recognition of aqueous biomaterials. Recognition and immobilization of various biomaterials including nucleotides, nucleic acid bases, amino acids, sugars, and peptides were widely investigated. The LB film can be also used for immobilization of enzymes in an ultrathin film on an electrode, resulting in sensor application. The LBL assembling method is available for wide range of biomaterials and provides great freedom in designs of layered structures. These advantages are reflected in preparation of thin-film bio-reactors where multiple kinds of enzymes sequentially operate. LBL assemblies were also utilized for sensors and drug delivery systems. This kind of assembling structures can be prepared on micro-size particle and very useful for preparation of hollow capsules with biological functions.

Animals↗

PubMedDate not supplied

Enzymatic hydrolysis of gelatin layers on used lith film using thermostable alkaline protease for recovery of silver and PET film.

To develop a new efficient and potential industrial enzymatic process for the recovery of silver and poly(ethylene terephthalate) (PET) from used lith film for printing, which has not been recycled at all, enzymatic hydrolysis of gelatin layers on lith film was investigated using the thermostabilized mutant enzyme of the alkaline protease from alkaliphilic Bacillus sp. B21-2. The rate of gelatin hydrolysis of lith film in a stirred-tank reactor increased with the temperature and enzyme concentration. The time required to complete the hydrolysis of gelatin on lith film was longer than that on X-ray film because of the tightly cross-linked structure of the gelatin layers of lith film. The time required to complete the hydrolysis by using the mutant enzyme was less than that using the wild-type enzyme. The gelatin hydrolysis of lith film was well explained by a model that took into consideration a number of physical processes in addition to the chemical process.

Enzyme Stability↗

PubMed2003

High precision film dosimetry with GAFCHROMIC films for quality assurance especially when using small fields.

Treatment units for radiosurgery, brachytherapy, implementation of seeds, and IMRT generate small high dose regions together with steep dose gradients of up to 30%-50% per mm. Such devices are used to treat small complex-shaped lesions, often located close to critical structures, by superimposing several single high dose regions. In order to test and verify these treatment techniques, to perform quality assurance tasks and to simulate treatment conditions as well as to collect input data for treatment planning, a GAFCHROMIC film based dosimetry system for measuring two-dimensional (2-D) and three-dimensional (3-D) dose distributions was developed. The nearly tissue-equivalent radiochromic GAFCHROMIC film was used to measure dose distributions. A drum scanner was investigated and modified. The spectral emission of the light source and the filters together with the efficiency of the CCD filters for the red color were matched and balanced with the absorption spectra of the film. Models based on refined studies have been developed to characterize theoretically the physics of film exposure and to calibrate the film. Mathematical descriptions are given to calculate optical densities from spectral data. The effect of darkening has been investigated and is described with a mathematical model. The influence of the scan temperature has been observed and described. In order to cope with the problem of individual film inhomogeneities, a double irradiation technique is introduced and implemented that yields dose accuracies as good as 2%-3%. Special software routines have been implemented for evaluating and handling the film data.

Absorptiometry, Photon↗

PubMed1996

Evaluating sol-gel ceramic thin films for metal implant applications. II. Adhesion and fatigue properties of zirconia films on Ti-6AI-4V.

The degree to which ceramic coatings or thin films applied to bone-interfacing metallic implants can improve the overall performance of these implants with respect to implant fixation, wear, or corrosion relies especially on the response of these films to loading. In this study, the adhesion and fatigue properties of sol-gel zirconia films that could be reproducibly deposited onto polished Ti-6AI-4V substrates was investigated. For zirconia films on the order of 100 nm thick, a shear lag-based strain approach indicated a shear adhesion strength of approximately 275 MPa. Small variations in film thickness and substrate surface preparation had little effect on this adhesion, which was believed to be due to alkoxide molecule interactions with free hydroxyl groups on the substrate surface as well as some limited interfacial diffusion following the 500 degrees C anneal. Subsequent fatigue testing of these films in air using novel tapered rotating beam fatigue samples demonstrated their excellent fatigue characteristics, with films surviving up to 10(7) cycles, the endurance limit of the Ti-6AI-4V (approximately 635 MPa). Overall, the exceptional mechanical properties of this ZrO2/Ti-6AI-4V system along with the inherent advantages of sol-gel processing support continued studies to utilize this technology for implant surface modification.

Alloys↗

PubMed1999

Evaluating sol-gel ceramic thin films for metal implant applications: III. In vitro aging of sol-gel-derived zirconia films on Ti-6Al-4V.

Sol-gel-derived zirconia films were deposited onto polished Ti-6Al-4V substrates by dip-coating from an alkoxide precursor solution. No change in morphology of the zirconia film was observed after aging at 37 degrees C for 4-12 weeks in pH 4.0 buffer solution or Hanks' balanced salt solution (HBSS), although a precipitate predominantly composed of calcium phosphate was formed on those films aged in HBSS. X-ray diffraction identified the phase of the zirconia film as either cubic or tetragonal, and revealed no degradation to the monoclinic phase after aging. By a substrate straining test, the fracture strain of the coating was revealed to be 1.5%, above the yield strain of the titanium alloy substrate. At this strain level, through-thickness cracks formed in the coating where slip bands emerged from the substrate. Qualitatively, the adhesion of the film was sufficient to prevent gross delamination of the film at high strain levels, although small regions of delamination were caused by compressive buckling of the film. This behavior indicates generally good adhesion. No change in this behavior was observed after aging.

Alloys↗

PubMed2001

Slow release of drug through deformed coating film: effects of morphology and drug diffusivity in the coating film.

The effects of the morphology and drug diffusivity in the coating film on the slow release characteristics have been analyzed numerically under the constraint that the volume of the coating film and the drug matrix is maintained constant. Two different systems of coated particles with deformed coating films were studied and their release characteristics compared with those of the coated particles having spherical coating films. The average release rate, fractional release, drug concentration profiles, and the initial burst of drug were found to be strongly influenced by the ratio of drug diffusivity in the coating film to that in the drug matrix D(r) (i.e., dimensionless drug diffusivity in the coating film). Increasing D(r) always increased the release rate, the fractional release, and the initial burst of drug, but reduced the initial lag times of drug release. The effect of shape deformation was very significant in the drug concentration profiles and the initial lag times; in contrast, it was not so substantial on the fractional release and the average release rates. The morphology difference in the deformed systems was also found to affect the release characteristics to different extents. Increasing the degree of the shape deformation, represented by the perturbation parameter epsilon, always reduced the effective surface area for the controlled release of drug. Because of the compensation effects between decreasing surface area and the non-uniform mass flux distribution, even though the heterogeneity of surface mass flux distribution would become more considerable, the effects of increasing shape deformation to the overall release rate would be less than expected unless the coating film was deformed significantly enough. The effect of the shape deformation and the morphology difference become less effective to differentiate the release characteristics with increasing D(r).

Delayed-Action Preparations↗

PubMed2002

In situ polymerized polyaniline films. 4. Film formation in dispersion polymerization of aniline.

Polyaniline films were grown on glass supports during dispersion polymerizations of aniline using poly(N-vinylpyrrolidone) and hydroxypropylcellulose as stabilizers. The initiation of polyaniline chains is proposed to be heterogeneously catalyzed by the surfaces immersed in the reaction mixture. Film formations in dispersion and precipitation polymerizations are compared. Surfometry and optical absorption were used to assess the submicrometer film thickness, and FTIR spectroscopy was used to analyze the chemical structure of films and prove the absence of stabilizer. The film thickness was proportional to the dimensions of simultaneously produced colloidal polyaniline particles. The conductivity of films increased with increasing film thickness.

Aniline Compounds↗

PubMed1991

Lipid-protein surface films generated from membrane vesicles: selfassembly, composition, and film structure.

Lipid-protein films at the air-water interface were generated from a variety of native vesicles and from vesicles derived from lipid extracts. A technique is described which is particularly suitable for the generation of films from small amounts of material at high yield and velocity. In all instances, 10 microliters vesicle suspensions containing 25 micrograms protein yield at least 50 cm2 film area at a constant surface pressure of 12 mN/m within minutes. Upon formation, surface films are separated from vesicles by use of shear forces. Complete separation is demonstrated by electron microscopy and surface pressure-area diagrams. The latter confirms previous conclusions that surface films generated from lipid vesicles are organized as a monolayer. Analysis of lipid-protein surface layers reveals that their lipid to protein ratios match those of the vesicles used, within a factor of two, irrespective of whether films are generated at high or low surface pressure. Surface denaturation of membrane proteins is shown to be effectively prevented when the film is generated and held at high surface pressure (greater than or equal to 15 mN/m). Upon surface pressure jumps from high to low values, denaturation kinetics revealed activation areas of 1.5 (+/- 0.2) nm2.

Animals↗

PubMed2004

Dispersion of functional tetraphenylporphyrin-ligated metal into ultra-thin flexible acrylate films. 1. Preparation of thin films.

As functional metal complexes, copper phthalocyanine (CuPc) and Cobalt (II) meso-tetraphenylporphyrin (CoTPP) were chosen to prepare metal complex/polymer hybrid thin films which were prepared by metal complex sublimation and reactive monomer evaporation onto the glass substrate in the bell jar reactor in vacuum conditions. The polarized transmission micrograph images show that the film deposited at 80 degrees C contains uniformly dispersed tiny grains and the film deposited at 30 degrees C is amorphous and homogeneous. As the deposition rate increases, the crystalline clusters were found and were dispersed uniformly. Those crystalline clusters are not to be developed by recrystallization process. Deposited metal complex/acrylate hybrid thin films were in situ photopolymerized. The kinetics of photopolymerization was investigated by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The thickness of the films was about 200 nm. The reactive monomer acts as a solvent to avoid the recrystallization of metal complexes and to have two-compositional continuous phase. The percent of metal complex can be adjusted up to 60% by controlling the metal complex sublimation rate. A good achievement in the uniformity and continuity of the film matrix has been made and the recrystallization of metal complex in the hybrid films has not been observed.

Acrylates↗

PubMed2005

Morphology characterization of layer-by-layer films from PAH/MA-co-DR13: the role of film thickness.

We report on the use of dynamic scale theory and fractal analyses in the study of distinct growth stages of layer-by-layer (LBL) films of poly(allylamine hydrochloride) (PAH) and a side-chain-substituted azobenzene copolymer (Ma-co-DR13). The LBL films were adsorbed on glass substrates and characterized with atomic force microscopy with the Ma-co-DR13 at the top layer. The granular morphology exhibited by the films allowed the observation of the growth process inside and outside the grains. The growth outside the grains was found to follow the Kardar-Parisi-Zhang model, with fractal dimensions of ca. 2.6. One could expect that inside the grains the morphology would be close to a Euclidian surface with fractal dimension of ca. 2 for any growth stage. The latter, however, was observed only for thicker films containing more than 10 bilayers. For thinner films the morphology was well described by a self-affine fractal. Such dependence of the growth behavior with the film thickness is associated with a more complete coverage of adsorption sites in thicker films due to diffusion of polymer molecules.

Azo Compounds↗

PubMed2000

Thin-film glucose biosensor based on plasma-polymerized film: simple design for mass production.

We propose a simple thin-film glucose biosensor based on a plasma-polymerized film. The film is deposited directly onto the substrate under dry conditions. The resulting films are extreme thin, adhere well onto the substrate (electrode), and have a highly cross-linked network structure and functional groups, such as amino groups, which enable a large amount of enzyme to be immobilized. Since this design allows fabrication through a dry process, with the exception of the enzyme immobilization, which is the last stage of the process, the chip fabrication can be designed as a full-wafer process to achieve mass production compatibility. The resulting sensors produced using this film are more reproducible, exhibit lower noise, and reduce the effect of interference to a greater degree than sensors made using conventional immobilization methods, e.g., via 3-(aminopropyl)triethoxysilane. The obtained film is a good interfacial design between enzyme and electrode; enzyme two-dimensionally locates very close to the electrode in a manner that is quite reproducible. Therefore, a wide dynamic range (up to 60 mM) and rapid response time (11.5+/-0.8 s) were obtained. Because of its highly cross-linking network structure, the amperometric response due to interferences such as ascorbic acid and acetaminophen was reduced by size discrimination of plasma-polymerized films.

Biosensing Techniques↗

PubMed2000

Equivalent-circuit model for the thickness-shear mode resonator with a viscoelastic film near film resonance.

We derive a lumped-element, equivalent-circuit model for the thickness-shear mode (TSM) resonator with a viscoelastic film. This modified Butterworth-Van Dyke model includes in the motional branch a series LCR resonator, representing the quartz resonance, and a parallel LCR resonator, representing the film resonance. This model is valid in the vicinity of film resonance, which occurs when the acoustic phase shift across the film is an odd multiple of pi/2 rad. For low-loss films, this model accurately predicts the frequency changes and damping that arise at resonance and is a reasonable approximation away from resonance. Elements of the parallel LCR resonator are explicitly related to film properties and can be interpreted in terms of elastic energy storage and viscous power dissipation. The model leads to a simple graphical interpretation of the coupling between the quartz and film resonances and facilitates understanding of the resulting responses. These responses are compared with predictions from the transmission-line and Sauerbrey models.

Elasticity↗

PubMed2005

Tungsten allylimido complexes Cl4(RCN)W(NC3H5) as single-source CVD precursors for WNxCy thin films. Correlation of precursor fragmentation to film properties.

A mixture of the tungsten allylimido complexes Cl(4)(RCN)W(NC(3)H(5)) (3a, R = CH(3) and 3b, R = Ph) was tested as a single-source precursor for growth of tungsten nitride (WN(x)) or carbonitride (WN(x)C(y)) thin films. Films deposited from 3a,b below 550 degrees C contained amorphous beta-WN(x)C(y), while those deposited at higher temperatures were polycrystalline. Film growth rates from 3a,b ranged from 5 to 10 A/min over a temperature range of 450-650 degrees C, and the apparent activation energy for film growth was 0.15 eV. A plot of the E(a) values for deposition from Cl(4)(RCN)W(NR') [R' = Ph, (i)Pr, allyl] against the N-C imido bond strengths for the analogous amines R'NH(2) is linear, implicating cleavage of the N-C bond as the rate-determining step in film growth. The correlation of mass spectral fragmentation patterns for Cl(4)(RCN)W(NR') with film properties such as nitrogen content supports the significance of facile N-C bond cleavage in film growth.

Journal Article↗