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PubMed2000

Effects of application voltage and cathode and anode positions at electroporation on the in vitro permeation of benzoic acid through hairless rat skin.

The enhancing effect of electroporation on the in vitro skin permeation of benzoate was evaluated. Needle and ring electrodes made of Ag/AgCl were connected to an electrical power source, which produced exponentially decaying pulses. The needle electrode was kept in contact with the skin surface, and the ring electrode was positioned either on or under the skin. The electrical pulse was applied to abdominal hairless rat skin at 150-600 V every minute from 4 to 6 h during the 10-h permeation experiment. Skin permeation of benzoate was promoted by electroporation and the effect was increased by application of a higher voltage. No immediate recovery to the control flux, however, was observed for high voltage groups after turning off the voltage application. When the cathode and anode were separated by the skin membrane by setting in the epidermal and dermal sides, respectively, an iontophoretic effect may also play a role in benzoate flux. These results indicated that the drug permeation by electroporation is the result of passive diffusion and an iontophoretic effect as well as the electroporation effect.

Animals↗
PubMed2001

Cathodic adsorptive stripping square-wave voltammetry of the anti-inflammatory drug meloxicam.

The adsorptive behavior of the anti-inflammatory drug meloxicam was studied by cyclic, differentia-pulse and square-wave voltammetry on a hanging mercury drop electrode (HMDE). The drug was accumulated at HMDE and a well-defined stripping peak current was obtained at -1.42 V vs. Ag/AgCl (saturated KCl) electrode in acetate buffer solution (pH 5.0). A voltammetric procedure was developed for the determination of meloxicam using square-wave cathodic adsorptive stripping voltammetry (SW-CASV). The optimum working conditions for the determination of the drug were established. The analysis of meloxicam in human plasma was carried out satisfactorily.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

The effect of cathode ray tube display format on observer performance in dental digitized radiography: comparison with plain films.

Studies of observer performance with non-manipulated digital images are almost lacking; nor has the effect of cathode ray tube (CRT) display formats been evaluated. The present study compared the diagnostic accuracy of observers with and without clinical experience in evaluating intra-oral dental films and the corresponding non-manipulated digitized images. Three different-sized (5", 9", 17") monitors were used to study the effect of CRT display format. Artificial radiolucent and radiopaque lesions in dry human mandibles were examined. ROC curve areas were averaged and cross-tabulated according to viewing method and observer experience. For the total group, the non-manipulated digital images resulted in smaller ROC curve areas than the plain films for all CRT formats, with a significantly inferior result for the 17" images (p = 0.036). The increase in diagnostic accuracy of the digital images with decreasing CRT size was not significant (p > 0.05). There was some difference in the mean ROC curve areas between teachers and students, but the effect of the viewing methods was not significant. In terms of observer performance, the experienced observers demonstrated a reduced, and the inexperienced an increased, variability with the digital images compared with conventional film.

Clinical Competence↗
PubMed1993

Comparison of readability between liquid crystal displays and cathode-ray tubes.

Flat-panel displays, especially liquid crystal displays (LCDs), are almost universally used today. Do LCDs assure better readability than cathode-ray tubes (CRTs)? Two experiments were carried out to determine which type of display is better using a newly developed device. Four types of displays were tested; negative and positive CRTs, and LCDs with and without backlighting. Variables were the type of display, age, and gender. At first, analyses of readability using eye movements were conducted. Middle-aged subjects showed slower reading speed than young subjects. Then, experiments of pupillo-accommodative functions were carried out. Non-backlit LCDs reduced focusing speed among young subjects and reading performance in middle-aged subjects. Since middle-aged workers have more difficulties than young workers, they should have their vision properly corrected for VDT viewing, more appropriate displays and a more comfortable illuminance environment than young workers.

Adolescent↗
PubMed1993

Do liquid crystal displays assure better readability than cathode-ray tubes?

Flat-panel displays, especially liquid crystal displays (LCDs), are now firmly established as important devices for information displays. But do LCDs assure better readability than cathode-ray tubes (CRTs)? We carried out an experiment using four types of displays: negative and positive CRTs, and LCDs with and without backlighting. A syllable-checking task using the Japanese katakana alphabet was conducted among fifteen healthy workers. They were divided into three groups; Group 1 had five young males aged 25 to 29, Group 2 was made up of five young females aged 18 to 24, and Group 3 consisted of five middle-aged workers who were 40 to 50 years old. We used four ambient light levels: 200 lx, 500 lx, 1250 lx without reflected glare, and 500 lx with reflected glare, on the display screens from behind. The illuminance of the glare was approximately 200 cd/m2. Multiple regression analysis showed that non-backlit LCDs reduced reading performance in middle-aged subjects significantly. Since middle-aged workers have more difficulties than young workers, they need more appropriate displays and a more comfortable illuminance environment than younger workers.

Adolescent↗
PubMed2004

Room-temperature deposition of amorphous titanium dioxide thin film with high refractive index by a filtered cathodic vacuum arc technique.

Amorphous titanium dioxide (TiO2) thin film has been prepared by a filtered cathodic vacuum arc technique at room temperature. It was concluded from the core level of Ti 2p 3/2 (458.3 eV) and O 1s (529.9 eV) and their deviation in binding energy (deltaBE = 71.6 eV) that only one of Ti oxidation states, Ti4+, existed in the film and the film was of ideal stoichiometry. The film possessed high transmittance, which can reach as high as that of a quartz substrate, especially in the visible range, owing to its optical bandgap of 3.2 eV. The high refractive index (2.56 at 550 nm) and low extinction coefficient (approximately 10(-4) at 550 nm) suggested that the film had a high packing density and a low scattering-center concentration. These good optical properties implied the film prepared by this technique was a promising candidate for optical application. Besides, the film was found to transform in the structure from amorphous to anatase crystalline when it was annealed at 300 degrees C, as evidenced by Raman and x-ray diffraction.

Journal Article↗
PubMed2003

Frequency-stabilized high-power violet laser diode with an ytterbium hollow-cathode lamp.

We have demonstrated in an ytterbium laser cooling and trapping experiment a high-power violet extendedcavity diode laser (ECDL) stabilized to the Yb resonant transition at 398.9 nm in an Yb hollow-cathode lamp. A frequency-dispersion signal, which we obtained by applying a modulation-free dichroic-atomic-vapor laser lock technique, allowed us to stabilize the violet ECDL at a frequency stability below 1 MHz at 1-s average time and a useful output power of 15 mW.

Journal Article↗
PubMed2002

Voltammetric characteristics of miconazole and its cathodic stripping voltammetric determination.

Miconazole is reduced at mercury electrode above pH 6 involving organometallic compound formation, responsible for an anomalous polarographic behavior. The electrodic process presents a large contribution of the adsorption effects. The drug can be determined by cathodic stripping voltammetry from 8.0 x 10(-8) to 1, 5 x 10(-6) molL-1 in Britton-Robinson buffer pH 8.0, when pre-accumulated for 30s at an accumulation potential of 0V. A relative standard deviation of 3.8% was obtained for ten measurements of 1.0 x 10(-7) molL-1 miconazole in B-R buffer pH 8.0 and a limit detection of 1, 7 x 10(-8) molL-1 was determined using 60s of deposition time and scan rate of 100 mVs-1. The proposed method is simple, precise and it was applied successfully for the determination of the miconazole in pure form and in commercial formulations, showing mean recoveries of 99.7-98.4%.

Antifungal Agents↗
PubMed2003

Flow injection electrochemical hydride generation of hydrogen selenide on lead cathode: critical study of the influence of experimental parameters.

A flow injection system for the determination of selenium by electrochemical hydride generation and quartz tube atomic absorption spectrometry is described. The generator consists of an electrolytic flow-through cell with a concentric arrangement and a packed cathode made of particulated lead. The influences of sample flow rate, carrier gas flow rate and electrolysis current on the hydrogen selenide generation have been critically studied. Both sample flow rate and electrolysis current play important roles in the efficiency of the hydride generation process. A characteristic mass of 2.4 ng and a concentration detection limit of 17 microg l(-1) were obtained for a sample volume of 420 microl.

Journal Article↗
PubMed2004

Detection of iron(III)-binding ligands originating from marine phytoplankton using cathodic stripping voltammetry.

The sample preparation and analytical methodology are described for detecting biologically produced iron(III)-binding ligands in laboratory cultures of coastal marine phytoplankton. The iron(III)-binding ligands from the culture media were purified by passage through a column packing with a hydrophobic absorbent. The concentrations and stability constants of the ligands were determined by adsorptive cathodic stripping voltammetry with competitive ligand equilibration. The analytical results of the cultivated cultures suggest that eukaryotic phytoplankton would produce iron(III)-binding ligands in analogy with other microorganisms.

Electrochemistry↗
PubMed2006

Determination of chitosan by cathodic stripping voltammetry.

A sensitive method for the determination of chitosan (CTS) by cathodic stripping voltammetry is presented. The method exploits a pair of oxidation-reduction peaks of CTS at -0.62 V (vs. SCE) and -0.54 V (vs. SCE), and an enhancement of the peak current of CTS observed in a 0.05 mol l(-1) potassium hydrogenphthalate buffer solution (pH 2.5). The peak current is linear with the concentration of CTS from 5.0 x 10(-7) to 1.5 x 10(-5) g ml(-1), and the detection limit is 1.0 x 10(-7) g ml(-1). We studied the characteristics and the mechanism of the electrode reaction, which proved that this process was diffusion controlled. This method was applied to determine the content of CTS in real samples with satisfactory results.

Chitin↗
PubMed1978

Reaction time to accelerating lines and dots on a cathode-ray tube.

Two experiments recorded the simple RT of 13 and 10 airline pilots, respectively, to accelerating lines and dots on a cathode-ray tube. In Exp. 1, dotted lines of six lengths moved in-line or frontally, and downward or to the right. Exp. 2 compared seven different in-line-moving solid lines with dot pairs of corresponding separations, and with single dots. RT increased with the length of in-line-moving solid lines but not when dotted lines were used. RT decreased with frontal movement of dotted lines. RT to dot pairs was shorter than to solid lines or single dots. Results indicate the importance of three factors: amount of movement information, visual angle, and inhibition of the retinal area stimulated.

Humans↗
PubMed1988

Serum cathodic trypsin-like immunoreactivity, pancreatic lipase, and pancreatic isoamylase as diagnostic tests of chronic pancreatitis or pancreatic steatorrhea.

We compared serum concentrations of cathodic trypsin-like immunoreactivity, pancreatic lipase, and pancreatic isoamylase as diagnostic tests of chronic pancreatitis (and of pancreatic steatorrhea in the 41 patients with steatorrhea) in 105 patients (57 men, 48 women) consecutively investigated because of clinical suspicion of chronic pancreatitis. Chronic pancreatitis (36 patients), pancreatic steatorrhea (24 patients), and other diseases were diagnosed without knowledge of the serum levels of the three enzymes. When evaluated by means of receiver operating characteristic curves, no differences were found in diagnostic performance of the enzymes with regard to chronic pancreatitis or pancreatic steatorrhea. The sensitivity and specificity for recognition of chronic pancreatitis ranged from 0.306 to 0.444 and from 0.942 to 0.986 when the discrimination values were chosen to give highest efficiencies. The similar ranges for pancreatic steatorrhea were 0.500-0.708 and 0.882-0.941. In conclusion, none of the three enzymes had any advantage over the others as diagnostic tests of chronic pancreatitis or of pancreatic steatorrhea. Only positive test results have clinical importance because of the low sensitivities of the three enzymes.

Adult↗
PubMedDate not supplied

Liquid-crystal display monitors and cathode-ray tube monitors: a comparison of observer performance in the detection of small solitary pulmonary nodules.

OBJECTIVE: To compare observer performance using liquid-crystal display (LCD) and cathode-ray tube (CRT) monitors in the interpretation of soft-copy chest radiographs for the detection of small solitary pulmonary nodules. MATERIALS AND METHODS: By reviewing our Medical Center's radiologic information system, the eight radiologists participating in this study (three board-certified and five resident) retrospectively collected 40 chest radiographs showing a solitary noncalcified pulmonary nodule approximately 1 cm in diameter, and 40 normal chest radiographs. All were obtained using a storage-phosphor system, and CT scans of the same patients served as the gold standard for the presence of a pulmonary nodule. Digital images were displayed on both high-resolution LCD and CRT monitors. The readers were requested to rank each image using a fivepoint scale (1 = definitely negative, 3 = equivocal or indeterminate, 5 = definitely positive), and the data were interpreted using receiver operating characteristic (ROC) analysis. RESULTS: The mean area under the ROC curve was 0.8901+/- 0.0259 for the LCD session, and 0.8716+/- 0.0266 for the CRT session (p > 0.05). The reading time for the LCD session was not significantly different from that for the CRT session (37.12 and 41.46 minutes, respectively; p = 0.889). CONCLUSION: For detecting small solitary pulmonary nodules, an LCD monitor and a CRT monitor are comparable.

Data Display↗
PubMed1985

Comparison of four schistosome excretory-secretory antigens: phenol sulfuric test active peak, cathodic circulating antigen, gut-associated proteoglycan, and circulating anodic antigen.

Several carbohydrate-containing antigens of schistosomes have been characterized and tests for these antigens or for the corresponding antibodies are increasingly being used for the diagnosis and clinical analysis of human schistosomiasis. Phenol sulfuric active peak (PSAP) and cathodic circulating antigen (CCA) are 2 soluble glycoproteins found in adult worms of Schistosoma mansoni. These antigens have some similar characteristics including solubility in trichloroacetic acid and non-binding or weak binding to DEAE cellulose which suggests these 2 compounds to be identical. PSAP and CCA were therefore compared using radioimmunoassays employing monoclonal antibodies to CCA and radiolabeled PSAP as well as inhibitory assays using the original glycoproteins as inhibitors. By these criteria PSAP and CCA were found to be different glycoproteins. Using similar techniques, 2 anodic schistosome compounds, gut-associated proteoglycan (GASP) and circulating anodic antigen (CAA) were found to be identical. We now propose to call this later material GASCAP (gut-associated circulating anodic proteoglycan).

Animals↗
PubMed1988

Schistosoma mansoni: ultrastructural localization of the circulating anodic antigen and the circulating cathodic antigen in the mouse kidney glomerulus.

In this study two major antigens of Schistosoma mansoni, the circulating anodic antigen (CAA) and the circulating cathodic antigen (CCA), were localized ultrastructurally in glomeruli of S. mansoni infected mice. These antigens were studied by direct gold labeling in which anti-CAA and anti-CCA monoclonal antibodies were labeled with 5 and 15 nm gold particles, respectively. CAA and CCA were demonstrable in glomeruli at week 3 in the basement membrane and from 5 weeks in moderately electron-dense material of the mesangial matrix. Both antigens were also encountered in fenestrae of the endothelial cells, in filtration slit pores, and on the luminal membranes of the epithelial cells. It appears that CAA and CCA are arrested by the glomerular basement membrane and deposited in the mesangial matrix. CAA was seen in considerably smaller amounts than CCA. This was ascribed to the fact that CAA, but not CCA, is repelled by the negative charge of the capillary walls and the glomerular basement membrane.

Animals↗
PubMed1992

Improved diagnostic performance of the circulating antigen assay in human schistosomiasis by parallel testing for circulating anodic and cathodic antigens in serum and urine.

Serum and urine levels of two Schistosoma circulating antigens, the circulating anodic antigen (CAA) and the circulating cathodic antigen (CCA), were determined by monoclonal antibody-based enzyme-linked immunosorbent assays in 56 Egyptian patients infected with S. mansoni and in 12 patients infected with both S. mansoni and S. haematobium. Both CAA and CCA could be specifically demonstrated in 82% and 88% of the serum samples and in 88% and 87% of the urine samples, respectively. While complete specificity was maintained, sensitivity was increased to a range of 91-98% by parallel use of the two circulating antigen assays, i.e., an individual with a positive titer for at least one of the assays was considered to be infected. A combination of CAA and CCA determinations in urine samples only resulted in a sensitivity of 94%. However, the highest sensitivity was achieved when the serum-CCA assay was combined with the urine-CCA assay (98%) or with the urine-CAA assay (97%). Sensitivity could not be increased further by combining more than two tests. A significant correlation was demonstrated between the level of circulating antigen and the number of parasite eggs in feces in each of the four assays. In addition, the levels of CAA and CCA in serum and urine were significantly correlated with each other. Our results indicate that diagnosis of schistosome infections by detection of circulating antigens can be significantly improved by parallel testing for multiple antigens.

Adolescent↗
PubMed2004

[Newly developed monitor for IVR: liquid crystal display (LCD) replaced with cathode ray tube (CRT)].

For physicians who monitor images during interventional radiology (VR), we have built and been using a system that employs a liquid crystal display (LCD) instead of the conventional cathode ray tube (CRT). The system incorporates a ceiling-suspension-type monitor (three-display monitor) with an LCD on each of the three displays for the head and abdominal regions and another ceiling-suspension-type monitor (5-display monitor) with an LCD on each display for the cardiac region. As these monitors are made to be thin and light in weight, they can be placed in a high position in the room, thereby saving space and allowing for more effective use of space in the X-ray room. The system has also improved the efficiency of operators in the IVR room. The three-display folding mechanism allows the displays to be viewed from multiple directions, thereby improving the environment so that the performance of IVR can be observed.

Data Display↗