Determination of the morphology of soot aggregates using the relative optical density method for the analysis of TEM images

This paper deals with expanded polystyrene (EPS) as a potential source of smoke. We compared specific optical density of smoke from EPS and EPS strengthened by glass fibre mash and plaster which is used in external thermal insulation composite systems (ETICS). There was used testing method by ISO 5659 Plastics Smoke generation Part 2: Determination of optical density by a single-chamber test. The samples were exposed to a constant 50 kW.m-2 of thermal radiation. There was not used a pilot burner. During flame combustion samples evolved high amount of smoke. Samples from EPS released more smoke like samples with ETICS cover.

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Measurement of hemoglobin oxygen saturation in capillaries

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1987.252.5.h1031 ◽

1987 ◽

Vol 252 (5) ◽

pp. H1031-H1040 ◽

Cited By ~ 8

Author(s):

M. L. Ellsworth ◽

R. N. Pittman ◽

C. G. Ellis

Keyword(s):

Light Intensity ◽

Oxygen Saturation ◽

Red Blood Cells ◽

Optical Density ◽

Blood Cells ◽

Striated Muscle ◽

Cheek Pouch ◽

Retractor Muscle ◽

Hamster Cheek Pouch

We present a computer-aided videodensitometric method for the determination of oxygen saturation in red blood cells flowing through capillaries of the hamster cheek pouch retractor muscle. The optical density (OD) of red blood cells is determined at two wavelengths. At the first, 431 nm, there is a maximum difference between absorption by oxygen deoxyhemoglobin. At the second, 420 nm, absorption is equal for the two absorbing species (isosbestic wavelength). In capillaries of the retractor muscle a relationship between oxygen saturation (S) and the following OD ratio was obtained as S = -1.71 (OD431/OD420) + 2.20. The error (95% confidence interval) in oxygen saturation associated with a determination of the OD ratio is estimated to be +/- 4.8%. The computerization of the method employs a frame-by-frame analysis of the light intensity over a selected capillary segment. The light intensity waveform along the segment is digitized and the minimum (I) and maximum (I0) light intensities are used to compute an optical density (OD = log10 [I0/I]). These minimum and maximum intensities correspond to the presence and absence of a red blood cell, respectively. The method permits the off-line analysis of videotaped scenes and provides a means of assessing the extent of temporal and spatial heterogeneity of oxygen saturation in selected capillary networks. The method has been developed for use in capillaries in transilluminated striated muscle but should be generally applicable to the measurement of capillary oxygen saturation in other tissues.

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A spectrophotometric method for determination of fluorophore-to-protein ratios in conjugates of the blue fluorophore 7-amino-4-methylcoumarin-3-acetic acid (AMCA)

Journal of Histochemistry & Cytochemistry ◽

10.1177/38.1.1688452 ◽

1990 ◽

Vol 38 (1) ◽

pp. 87-94 ◽

Cited By ~ 11

Author(s):

M W Wessendorf ◽

S J Tallaksen-Greene ◽

R M Wohlhueter

Keyword(s):

Acetic Acid ◽

Optical Density ◽

Extinction Coefficient ◽

Spectrophotometric Method ◽

Extinction Coefficients ◽

Beer's Law ◽

Beer’S Law ◽

The Given

7-Amino-4-methylcoumarin-3-acetic acid (AMCA) has been found to be a useful fluorophore for immunofluorescence. The present study describes a spectrophotometric method for determining the ratio of moles AMCA to moles protein (or the f/p ratio) in an AMCA-conjugated IgG. The concentration of a substance absorbing light can be determined spectrophotometrically using Beer's Law: Absorbance = Concentration x Extinction coefficient. From Beer's law, one can derive the following formula for determining the f/p ratio of AMCA-IgG conjugates: f/p = (epsilon 280IgG).A350 - (epsilon 350IgG).A280/(epsilon 350AMCA).A280 - (epsilon 280AMCA).A350 where A is the optical density of the conjugate at the given wavelength and epsilon is the extinction coefficient of a substance at the wavelength specified. Using conjugates of model proteins, it was found that the extinction coefficients of the AMCA moiety of AMCA-conjugated protein were 1.90 x 10(4) at 350 nm and 8.29 x 10(3) at 280 nm. Similarly, it was found that the extinction coefficients of swine IgG were 1.56 x 10(3) at 350 nm and 1.26 x 10(5) at 280 nm. Thus, for AMCA-conjugated swine IgG: f/p = (1.26 x 10(5)).A350 - (1.56 x 10(3)).A280/(1.47 x 10(4)).A280 - (6.42 x 10(3)).A350 [corrected]. Based on this formula, the f/p ratios of some AMCA-IgG conjugates useful for immunohistochemistry have been found to range between 6 and 24.

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Expiremental determination of the optical density of states for phthalocyanines and porphyrins

Chemical Physics Letters ◽

10.1016/0009-2614(68)85001-8 ◽

1968 ◽

Vol 2 (4) ◽

pp. 207-209 ◽

Cited By ~ 31

Author(s):

B.H. Schechtman ◽

W.E. Spicer

Keyword(s):

Density Of States ◽

Optical Density

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Use of an optical density ruler in measurements of dye-dilution curves

Journal of Applied Physiology ◽

10.1152/jappl.1964.19.2.347 ◽

1964 ◽

Vol 19 (2) ◽

pp. 347-353 ◽

Cited By ~ 4

Author(s):

James B. Bassingthwaighte ◽

Anthony W. T. Edwards ◽

Earl H. Wood

Keyword(s):

Indocyanine Green ◽

Optical Density ◽

Light Transmission ◽

Accurate Estimation ◽

Calibration Constant ◽

Nonhomogeneous Media ◽

Dye Dilution ◽

Logarithmic Relationship ◽

Dilution Curves

The inapplicability of Beer's law to densitometry of dyes in whole blood or other nonhomogeneous media has been long known. When using a densitometer whose output is directly proportional to the light transmitted, a simple transformation— log X = log (x – x0)—can be employed to allow rapid, accurate estimation of dye concentration. This is facilitated by use of an optical density ruler. The transformation, X = x – x0, can be made mechanically, by shifting the infinity position of the ruler with reference to the zero light transmission position, or electrically, by appropriate use of zero suppression in the densitometer circuit. The transformation results in an exponential (logarithmic) relationship between light transmitted and concentration of the dye (indocyanine green). Readings of relative optical density obtained by use of the ruler are multiplied by a calibration constant to calculate dye concentration. The principles of the transformation have been applied to the determination of the optimal zero suppression required for maintenance of constant sensitivity of the densitometer in the presence of various levels of background dye. densitometer calibration; indocyanine green densitometer; calibration of dye-dilution curves; correction of dye-dilution curves Submitted on September 13, 1963

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GENETIC STUDIES OF PIGMENTATION OF STAPHYLOCOCCUS AUREUS

Canadian Journal of Microbiology ◽

10.1139/m67-051 ◽

1967 ◽

Vol 13 (4) ◽

pp. 389-395 ◽

Cited By ~ 2

Author(s):

Robert A. Altenbern

Keyword(s):

Staphylococcus Aureus ◽

Optical Density ◽

Point Mutations ◽

Low Frequency ◽

Pigment Content ◽

Single Site ◽

Genetic Studies ◽

Large Numbers ◽

Acridine Dyes

Exposure of cells of several strains of Staphylococcus aureus to 50 or 100 μg of N-methyl-N′-nitro-N-nitrosoguanidine for 30 to 60 minutes induced large numbers of mutants with pigment content different from that of the parent. By determination of the amount of pigment as related to the optical density of the cells, four to seven classes of pigmentation mutants could be defined. Mutants with pigment content differing from that of the parent could readily be mutated to other pigmentation states and are thus probable point mutations. In contrast, completely white mutants could not be induced by the mutagen to any degree of pigmentation and possibly represent minor deletions or cumulative single-site mutations in the chromosome. Growth of parent strains in media containing acridine dyes occasionally produced a low frequency (0.01%) of white mutants. Mutants differing in pigment content from that of the parent were unable to produce coagulase during growth, although the parent cultures elaborated considerable coagulase under identical conditions.

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