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At least 109 records · Page 6Linked to original sources
PubMed1975

[Material-testing studies for the rationalization of the technology of stomatological cold curing-plastics].

Materials scientific studies on the rationalization of the processing of stomatological cold-curing plastics. Hydropneumatic overpressure polymerization leads to a considerable rationalization of the processing of stomatological cold-curing plastics, but its effects on the course of polymerization and the properties of the polymerizate are yet not sufficiently elucidated. For this reason, the author studied in several test series the effects of various processing parameters (flask and overpressure vessel; varying mixing ratios, pressures and temperatures) on the polymerization of Kallocryl-AS, a cold-curing plastic. The results obtained indicate that, under certain processing conditions, overpressure polymerization of cold-curing plastics may be recommended from the viewpoint of materials science.

Cold Temperature↗
PubMed1993

[The toxin-producing ability of salmonella from bovine test material].

Cell-free supernatants of 40 Salmonella strains of different serovars were tested for the existence of enterotoxic substances in the rabbit skin permeability factor test, rabbit ileal loop test, tissue culture assays (CHO K1, RTG-2), and baby mouse test. There were differences in the test results between the strains even within the same serovar. Correlation coefficients between the results of different toxin tests were low. It is therefore improbable that the "enterotoxic activity" of Salmonella is caused by only one toxic substance. The activities revealed in the different test systems could not be related to virulence or the epizootiological behaviour of the strains. The in vitro occurrence of the virulence factor "enterotoxin production" is lower for Salmonella than for E. coli and V. cholerae.

Animals↗
PubMed1975

[Concept formation in children with schizophrenia (from Piaget test material)].

The authors studied reasons of a domineering perceptive generalizations in the Piaget test by children with schizophrenia. In teaching the children to distinguish and measure different properties of objects, the most typical appeared to be the following actions: a complete or partial refusal to accomplish them, a substitution of measurements by a perceptive comparison, difficulties in the narration of personal activity in well developed speech. Better results were attained in those who were emotionally positive. On these grounds the authors presumed an autistical genesis of these disturbances.

Child↗
PubMed1986

Proficiency testing materials for pH and blood gases. The California Thoracic Society experience.

The California Thoracic Society Blood Gas Proficiency Testing Program distributed ampules from three separate lots of quality control products every three months as unknowns to participating clinical (survey) laboratories and ten selected reference laboratories. For eight quarters, aqueous buffers were distributed. For each lot, PCO2 and pH measurements varied within narrow ranges between laboratories. Concurrently, the PO2 measurements varied widely between reference laboratories as well as survey laboratories, but varied minimally when repeatedly assessed on each reference laboratory machine. Change to a fluorocarbon-containing emulsion as a testing medium resulted in a significant reduction in within model and overall variability for PO2. We attribute this reduction in variability to the higher O2 content and decreased temperature sensitivity for PO2 of the fluorocarbon-containing emulsion. Because we have no evidence that the magnitude of the interinstrument differences in PO2 found with these materials would be found with fresh human blood we recommend that regulatory agencies use the results of proficiency testing for PO2 cautiously.

Blood↗
PubMed1995

[Self assessment and actual intelligibility of speech audiometry test material].

Self-estimated and measured intelligibility were compared using different instructions in speech audiometric tests. The results of 69 tested persons reveal that there exist speech levels in both test procedures where the intelligibility reaches 0% or 100%, respectively. In general, self-estimated intelligibility was significantly higher than real identification. Therefore, the self-estimation of intelligibility does not appear as an appropriate procedure to automated speech audiometry. The results are a speech audiometric equivalent of the subject's to have correctly understood speech in daily life in which in fact was misunderstood. Connections to central speech processing seem to be possible. Audiologists might be influenced by the effect of overestimation of speech intelligibility as well. However, preliminary investigations concerning pseudohypacusis show different results.

Adolescent↗
PubMed1991

The nickel content of certain commercially available metallic patch test materials and its relevance in nickel-sensitive subjects.

The nickel contamination of the metallic patch test substances from 3 commercial sources was estimated by atomic absorption spectrophotometry. Contamination was generally greatest in the cobalt patch test substances. To determine whether the levels of contamination encountered were sufficient to produce a false positive patch test, 20 nickel-sensitive patients were patch tested to various concentrations of free elemental nickel in aqueous solution. The level of nickel contamination was less than that required to produce a false positive patch test in our patients, but was at a level which could produce false positive reactions in subjects highly sensitive to nickel.

Adolescent↗
PubMed2005

Comparison of pooled fresh frozen serum to proficiency testing material in College of American Pathologists surveys: cortisol and immunoglobulin E.

CONTEXT: The College of American Pathologists (CAP) provides proficiency testing (PT) surveys to laboratories around the world. OBJECTIVES: To compare diagnostic assay methods for serum/plasma cortisol and immunoglobulin (Ig) E in terms of their bias and precision, to determine how well CAP PT specimens simulate human serum, and to reassess proficiency test grading criteria in light of these findings. DESIGN: A participant-blinded, prospective trial. One vial of pooled fresh frozen serum (FFS) and 4 different admixtures of PT material (PTM) were sent to laboratories participating in PT surveys. PARTICIPANTS: Laboratories providing cortisol (>1000) or IgE (>230) results among the subscribers to the CAP surveys, Ligand (General) 2003, set K/KN-A and Chemistry 2003, set C-C. MAIN OUTCOME MEASURES: The main outcome measures were (1) bias among laboratories using the same method (peer groups), defined relative to the median of method means (MedMM); (2) imprecision as measured by the SD and coefficient of variation (CV) about each method mean; and (3) total error across laboratories for the FFS cortisol results, defined as |Bias Relative to Reference Method| + 2 SD. RESULTS: Cortisol method biases, relative to MedMM, ranged from -22% to 9% for the FFS challenge and from -24% to 36% for comparable PTM challenges. The method biases, relative to the reference method, ranged from -3% to 19% for the FFS challenge. The cortisol method CVs ranged from 4.2% to 13.6% for the FFS challenge and from 4.7% to 12.7% for comparable PTM challenges. Total error across laboratories ranged from 1.4 to 6.9 microg/dL (39 to 190 nmol/L) for the FFS challenge. Immunoglobulin E method biases, relative to MedMM, ranged from -8% to 9% for the FFS challenge and from -7% to 5% for comparable PTM challenges. The IgE method CVs ranged from 3.6% to 6.7% for the FFS challenge and from 3.4% to 9.8% for comparable PTM challenges. CONCLUSIONS: The bias for cortisol results was less with FFS than with PTM, but imprecision was comparable. The FFS MedMM was 8.5% higher than the reference value. Fresh frozen serum and PTM bias and imprecision for IgE methods were each less than 10%. Because some of the methods demonstrated greater bias when analyzing PTM than FFS, peer group grading of both these analytes is appropriate.

Clinical Laboratory Techniques↗
PubMed1989

Disinfection with gaseous formaldehyde. Second Part: Influence of test materials on formaldehyde residues and the bactericidal and sporicidal effectiveness.

The pararosaniline method for the determination of formaldehyde residues on test surfaces after exposure to gaseous formaldehyde was standardized as well as the methods of collection, preparation and desorption from the samples. The analysis of residues on plates of 5 different materials yielded the following amounts of residues after 60 minutes exposure to 3.2 mg HCHO1-1 air at 45 degrees C and a relative humidity (RH) of about 90%; silicon rubber 287.2 micrograms, lacquered polyurethane foam 109.6 micrograms, lacquered aluminium 30.3 micrograms, plexiglass 13 micrograms and stainless steel 4 micrograms HCHO 100 cm-2. The residues of formaldehyde on lacquered aluminum after an HCHO exposition with condensing layer at 20 and 30 degrees C were 10(3)-fold higher than after an exposition to gaseous formaldehyde without a condensing layer at a relative humidity of about 90% and a temperature of 40 degrees C. The inactivations of S. aureus and Bacillus subtilis spores on carriers of 5 different materials were determined under the same conditions (60 min, 3.2 mg HCHO 1-1 air, 45 degrees C and a RH of about 90%). The decimal reductions showed that Staphylococcus aureus ATCC 6538 was more readily inactivated on non porous plexiglass with a D-value of 0.7 min or stainless steel D = 1.1 min than on porous silicon rubber D = 3 min. For spores of Bacillus subtilis var. niger DSM 675, D-values of 1.6 min for plexiglass, 2.3 min for stainless steel, 2.7 min for lacquered aluminium, 3.2 min for lacquered polyurethane foam and 4.1 min for silicon rubber were registered.

Bacillus subtilis↗
PubMed1982

[Material testing of modern plaster substitutes].

4 Plaster substitutes were tested in order to obtain some information about their reaction to stress. 2 materials are made of glass fibre with resin (Scotchcast and Lightcast), one from another artificial product (Baycast) and the fourth consists of a mesh of pure resin (Hexelite). Their resistance to bending forces was correlated to the weight of the samples used. The results indicated that a product containing glass fibre as carrier for the resin is the most robust.

Casts, Surgical↗