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At least 487 records · Page 27Linked to original sources
PubMed1987

[The analysis of caramel colors. 1. Differentiation of classes of caramel coloring agents with Curie-point pyrolysis-capillary gas chromatography-mass spectrometry].

After an introduction on the production, classification, legislative regulations, toxicology, and analysis of caramel colours, a report is given on the examination of these colourings by Curie-point pyrolysis-capillary gas chromatography-mass spectrometry. This method enables the differentiation between the four classes of caramel colours on the basis of the most concentrated of more than 100 identified pyrolysis products, which requires small quantities of substance (100 micrograms) and short periods of time (1 h).

Carbohydrates↗
PubMed1992

A simultaneous three-color T cell subsets analysis with single laser flow cytometers using T cell gating protocol. Comparison with conventional two-color immunophenotyping method.

We describe a method for simultaneous analysis of CD3, CD4, and CD8 positive cells from whole blood utilizing single laser flow cytometers. All three T cell values are attained from a single test tube. CD4 and CD8 positive cells are identified only if they are CD3 positive. Thus the values obtained by this method for T helper/inducer and T cytotoxic/suppressor cells can be reported directly as a percentage of T lymphocytes. Analysis for CD4 and CD8 positive cells is accomplished, by first gating on CD3 positive T lymphocytes, hence the approach is referred to as a T gating method. As the third dye, conjugated to anti-CD3 monoclonal antibodies (MAbs), we utilized peridinin chlorophyll protein (PerCP), a new red fluorochrome. The proposed method may prove to be practical for monitoring disease progression in AIDS, where longitudinal T helper/inducer and T cytotoxic/suppressor cell enumeration must be performed unambiguously by a simple, reproducible, and fast method.

CD3 Complex↗
PubMed1996

Testing the indeterminacy of linear color mechanisms from color discrimination data.

It have previously been reported that, for some choices of the fixed spatial and temporal characteristics of test stimuli, it was possible to estimate the spectral sensitivities of chromatic mechanisms from chromatic discrimination data alone. If mechanism sensitivities could be reliably estimated for any choice of test stimuli characteristics, the influence of spatial and temporal factors on chromatic discrimination performance could be directly measured. Previous studies, using test stimuli with other spatio-temporal characteristics, have found equi-discrimination contours whose ellipsoidal shapes seem to preclude estimation of mechanisms. Since there is no commonly-accepted method for testing the adequacy of ellipsoidal fits of chromatic equi-discrimination contours, it is possible that alternative psychophysical procedures combined with more powerful statistical tests could detect the pattern of deviations from ellipticality reported previously. In this paper, we described psychophysical tests and statistical analyses that, taken together, provide a more powerful test of the indeterminacy of mechanisms than previous methods. We develop a method based on analysis of residuals for detecting the pattern of deviations from ellipticality. We apply these tests under fixed experimental conditions similar to those in which other researchers have found ellipsoidal equi-discrimination contours. For these conditions, for any of the tests performed, we do not reject the hypothesis that equi-discrimination surfaces are ellipsoidal.

Color Perception↗
PubMed1996

[Sensitivity of new color systems: "maximum entropy method" and angio-color. Comparative in vitro flow measurements].

AIM: The sensitivity of the two procedures for slow blood flow velocities in two flow phantoms examined and compared to conventional colour Doppler. METHOD: In two phantoms with vessels between 0.3 and 6 mm diameter the slowest measurable blood flow with the different techniques was determined. The influence of various application angles was also studied. RESULTS: The slowest blood flow velocity detected with the MEM technique was 0.6 mm/s and with the angio-technique 0.4 mm/s. Two different scan-heads were used; a 5 MHz probe for the MEM procedures and a 10 MHz probe for ultrasound angiography. Using a 10 MHz scan-head will most likely lead to increased sensitivity of MEM. Blood flow representation with the MEM technique is real-time, while several seconds of acquisition time are required for the angio-technique, which is a disadvantage during clinical use. Conventional Doppler was merely able to represent 15 mm/s blood flow. The angio-technique was less dependent on the application angle than the MEM procedure. CONCLUSION: The definitely increased sensitivity of the two colour methods open up new areas in the diagnosis of organ and tumour perfusion.

Blood Flow Velocity↗