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At least 19 recordsLinked to original sources
PubMed1992

Rigid and flexible thin-film multielectrode arrays for transmural cardiac recording.

Thin-film transmural cardiac multielectric arrays were fabricated using integrated-circuit processing techniques. Several substantial improvements were achieved over conventional handmade arrays such as a smaller cross-sectional area, a larger number of recording sites per needle, more accurately controlled size and spacing of the recording sites, smaller bipolar spacings, and higher throughout yield. These advantages allow for a higher density of closely spaced bipolar electrodes capable of monitoring complex voltage and gradient fields present during ventricular fibrillation and defibrillation. Both rigid and flexible arrays were fabricated and used in the acquisition of transmural electrical signals. The rigid multielectrode arrays were made of gold electrodes on a molybdenum substate, and the flexible arrays of silver and gold electrodes on a polyimide substrate. In vitro and in vivo testing of the thin-film transmural cardiac multielectrode arrays indicates that there are no adhesion or delamination problems observed during acute studies, no implantation difficulties, and that unipolar and bipolar recordings during normal sinus rhythm and injury potentials in unipolar recordings are similar to those obtained using the handmade electrodes.

Animals↗
PubMed1978

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

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

Blood Proteins↗
PubMed1979

Quantitative thin-layer chromatography: thin-film fluorescence scanning analysis of adriamycin and metabolites in tissue.

A rapid, non-hydrolytic thin-film fluorescence scanning method is described for the quantitation of adriamycin and metabolites in tissues. Adriamycin, with daunomycin added as the internal standard, was extracted from tissue homogenate which contained 500 micrograms of oxalic acid, with ice-cold 0.5 N hydrochloric acid--85% isopropanol, separated by thin-layer chromatography, and quantitated in situ via a fluorescence scanning technique. This method has a sensitivity to 0.05 microgram per gram of tissue.

Animals↗
PubMed1976

Studies on normal human bone marrow cultures in controlled environment thin-film culture systems.

Two thin film culture systems, the controlled environment steady state system (SS) and the rocker tube configuration of that system (RT), were used to identify some of the conditions that appear to maintain morphologic and functional characteristics of cells of human bone marrow explants in vitro. The systems configuration assured continual gassing, control and easy monitoring of the cultures. Cytocentrifuge preparations of media of specimens cultured in RT disclosed, though in decreasing numbers, various hematopoietic cells for periods exceeding one month. Hematopoietic cells shed from specimens cultured in the SS system were retained in the culture tubes; cells of the myelocytic series predominated for the first two weeks while an increasing number of monocytes and macrophages appeared in the media of of older cultures. Histologic examination of cultured explants disclosed preservation of the marrow architecture and the persistence of hematopoietic cells. Specimens cultured in RT tubes tended to be less cellular than similar cultures placed in dialysis bags or as cultured in the SS system. Immunoglobulins (Ig) were released into the culture media at a constant rate throughout the period of culture. Specimens that were cultured at a controlled pH of 7.4 released 2 to more than 4 times as much Ig as similar specimens maintained at a pH level of 7.1. There were no definitive differences in Ig levels in the cultures maintained at comparable pH levels and overlaid with various CO2 concentrations, i.e. 2%, 5%, 10% similarly, no differences in Ig levels were found in specimens cultured in media containing fetal bovine sera as opposed to horse sera.

Bone Marrow↗
PubMed1976

Rapid analytic method for adriamycin and metabolites in human plasma by a thin-film fluorescence scanner.

A rapid and highly sensitive method is described for the quantitative determination of adriamycin and metabolites in plasma. Adriamycin (Ad) with daunorubicin added as the internal standard was extracted from plasma with chloroform-isopropanol (1:1), separated by thin-layer chromatography (TLC), and quantitated in situ via a fluorescence scanning technique. This method represents one of the very few reliable quantitative TLC methods and is suitable for the routine determination of Ad in plasma in amounts as low as 2 ng/ml. Plasma Ad levels at 24 hours in rabbits and in patients both given a 1-mg/kg dose, previously regarded as difficult to be measured, are now easily measurable using as little as 0.5 ml of plasma. Multiple samples (ten to 15) can be analyzed by this method within a day.

Animals↗
PubMed1992

Mechanism and strength of bonding between two bioactive ceramics in vivo.

A study was conducted to examine the mechanism and strength of bonding between two bioactive ceramic plates in vivo. Rectangular plates (15 mm X 10 mm X 2 mm) of Bioglass, apatite-wollastonite-containing glass ceramic (designated A-W.GC), and two types of hydroxyapatite sintered at 900 degrees C and 1200 degrees C (designated HA900 and HA1200) were prepared. Two plates of the same materials tied together with silk thread were implanted subcutaneously into rats. The force required to detach the mutually bonded bioactive ceramic plates was measured 4, 8, 12, and 24 weeks after implantation. The interface between the two bonded plates was examined by SEM-EPMA and thin-film x-ray diffraction analysis. At 24 weeks after implantation, the mutual bonding of Bioglass and A-W.GC was stronger than that of the two HA types. SEM-EPMA and thin-film x-ray diffraction analysis of the bonded area of Bioglass and A-W.GC plates showed bonding zones with apatite in the margins, and a bonding zone with calcite in the center. The greater strength of bonding of Bioglass and A-W.GC plates compared with the two types of HA plate 24 weeks after implantation is explained by the wider bonding zone provided by the calcite layer formed in the center of the plates, which is considered to have been perfused with PO4-poor body fluids resulting from PO4 consumption for apatite formation in the margins.

Animals↗
PubMed1979

Generation of aspartate aminotransferase multiple forms by deamidation.

The development of aspartate aminotransferase subforms in vitro was followed by densitometry after thin-film isoelectric focusing. At the same time ammonia production was measured. Each reaction can be expressed in terms of a first-order process in which 2 mol of glutamine or asparagine/mol of dimer are deamidated with a half time of 22 days. The more negatively charged subforms developed in vitro were almost fully active. Another process occurred leading to inactivation by coenzyme modification, and this was independent of deamidation. Although the enzyme formed absorbed maximally at 340nm, it was different from the naturally occurring inactive enzyme that absorbs at this wavelength.

Ammonia↗
PubMed1977

Tear-film dynamics and oxygen tension under a circular contact lens.

The cornea requires a minimum level of oxygenation; this may be prevented by a contact lens, and corneal swelling and other undesirable effects may result. By employing thin-film lubrication theory, this study derives analytical solutions for tear-film velocity components and pressure under a circular contact lens. Oxygen-tension contours are then obtained for various values of squeeze action and parallel motion of the lens.

Contact Lenses↗
PubMed1992

Regeneration microelectrode array for peripheral nerve recording and stimulation.

A microelectrode array capable of recording from and stimulating peripheral nerves at prolonged intervals after surgical implantation has been demonstrated. The microelectrode array, fabricated on a silicon substrate perforated by multiple holes (referred to as via holes), is implanted between the ends of a surgically severed nerve. Regenerating tissue fixes the device in place to provide a stable mapping between the microelectrodes and the axons in the nerve. Processes were developed for the fabrication of thin-film iridium microelectrodes, micromachined via holes, and silicon nitride passivation layers. All fabrication methods were designed to be compatible with standard CMOS/BiCMOS processes to allow for on-chip signal processing circuits in future designs. Such arrays, implanted in the peroneal nerves of rats, were used to record from and stimulate the nerves at up to 13 months postoperatively.

Animals↗
PubMedDate not supplied

Demonstration of megavoltage and diagnostic x-ray imaging with hydrogenated amorphous silicon arrays.

Flat-panel imagers consisting of the first large area, self-scanning, pixelated, solid-state arrays made with hydrogenated amorphous silicon (a-Si:H) are under development by the authors for applications in diagnostic x-ray and megavoltage radiotherapy imaging. The arrays, designated by the acronym MASDA for multi-element amorphous silicon detector array, consist of a two-dimensional array of a-Si:H photodiodes and thin-film transistors and are used in conjunction with scintillating materials. Imagers utilizing MASDA arrays offer a variety of advantages over existing technologies. This article presents initial megavoltage and diagnostic-quality x-ray images taken with several such arrays including the first examples of anatomical-phantom images. The external readout electronics and imaging techniques required to obtain such images are outlined, the construction, operation, and advantages of the arrays briefly reviewed, and the future potential of this new technology discussed.

Diagnostic Imaging↗
PubMed1992

[The preparation and stability of liposome-encapsulated Ara-A].

This paper uses several preparation methods, such as thin-film, reverse-phase evaporation and freeze-thawing methods, and also compares encapsulation percentage of Ara-A in liposome (EN%) of these methods. The best operational conditions of preparing liposome-encapsulated Ara-A are explored. A higher EN%, about 50%, which is ten times that reported in foreign literature, is obtained by using improved freeze-thawing method, and this method is easy to operate and repeatable. At the same time, the physical and chemical stabilities of the liposome-encapsulated Ara-A were observed. The result shows that there are no distinct changes in shape, size distribution of liposome, and EN% as well as Ara-A contained in liposome by means of sterilization at 100 degrees C for 30 minutes. Accelerating test at a constant temperature indicates that liposome-entrapped Ara-A has certain chemical stability.

Drug Stability↗
PubMed1976

Controlled environment culture of bone marrow explants from human myeloma.

Bone marrow biopsy specimens from patients with myeloma were cultured in either 1 of 2 thin-film culture systems, a controlled environment steady state system or a rocker tube configuration of the system, for periods up to 42 days. Both functional and morphological characteristics of the myeloma cells were well-maintained in these systems. Cytocentrifuge preparations of the culture media disclosed hematopoietic cells that included from 5% to almost 100% plasma cells. Histological examination of the cultured specimens disclosed infiltration of the marrow with myeloma cells. Myeloma proteins were released at a steady rate throughout the period of culture after the 1st 4 days. Bone-resorbing activity was demonstrated in the culture media in 7 of 9 myeloma culture media and was well maintained, particularly during the 1st week of culture. This activity was associated with severe osteolytic lesions in the donor patient and marked infiltration of the cultured specimen by myeloma cells. The potential use of these organ culture systems for the further definitive identification of the factor responsible for bone destruction in myeloma is discussed.

Bone Marrow↗
PubMed2026

Enhanced Performance in All-Inorganic AgBiS2 Photodetectors via Oxygen-Inhibited Spray Pyrolysis Deposition.

AgBiS2 has emerged as a promising optoelectronic material due to its broad spectral response and strong light absorption. However, the current use of high-boiling solvents and organic buffers restricts fundamental studies and further performance optimization of AgBiS2's intrinsic properties. In this study, we develop an organic buffer-free AgBiS2 photodetector prepared using a low-temperature ultrasonic spray pyrolysis technique. Our theoretical analysis revealed that oxygen doping alters the optoelectronic characteristics by enhancing the density of states near the Fermi level, leading to consequent severe nonradiative charge carrier recombination. By incorporating excess thiourea while maintaining optimal substrate temperature for enhanced crystallinity, we successfully suppress oxygen defects and consequently improve photodetection performance. The optimized device exhibits a high responsivity of 0.046 A W-1 at 1050 nm, a low noise level (<8.5 &#xd7; 10-19 A2 Hz-1), and a fast response time (0.07 &#x3bc;s rise, 0.60 &#x3bc;s decay). Benefiting from the rapid response, the photodetector delivers high-resolution imaging with sharp edge definition. This work eliminates the interference of organic buffer layers to directly reveal how oxygen defect modulation affects the intrinsic optoelectronic properties of AgBiS2, offering a scalable pathway for high-performance, solution-processed photodetectors.

near-infrared detector↗