Densitometer traces

Eig. 15. Micro densitometer tracings of x-ray line exposures with line widths of (a) 10 and (b) 1000 p.m. 

Figure 5. Densitometer traces of UV-photonegatives. Arabic numerals indicate the cell number which starts from the cell just before Si formation.

As has been commented upon in other papers in this symposium, methods for measurement of intensities in fiber diagrams have received little attention in the last 15 years, during which time considerable progress has been made in handling the atomic coordinates for least squares refinement. Most intensity data has been obtained from linear densitometer traces through the x-ray reflections. We used these procedures for our work on cellulose I and 6-chitin. For cellulose I, (1 ) the area under the peak on a radial scan was determined after subtraction of an estimated Current addresses ... 

Figure 2. Densitometer tracings illustrating the isozyme migration patterns of five EAP phenotypes during electrophoresis for 4 hr at ()°C. The s and s storage bands can also be seen.

Figure 3. Densitometer tracings and accompanying photographs of EAP phenotype B illustrating the loss of activity of the b isozyme and increase in activity of the c isozyme during storage at 25°C. Samples were taken from clotted blood. Electrophoresis was carried out for 15 hr at 5°C. The successive densitometer tracings shown were made from the EAP phenotype B pattern located on the left in the photograph.

Figure 5. Densitometer tracings illustrating the loss in activity of the b isozyme of EAP phenotype CB in a dried bloodstain stored at 25°C...

Fig. 4-11. Transverse section of a spruce tracheid photographed in UV light (240 nm) (Fergus et a/., 1969). The densitometer tracing has been taken across the tracheid wall along the dotted line. S, secondary wall ML, compound middle lamella CC cell corner.

Figure 7. Densitometer tracings for soymilk proteins and RDF fractions as a function of heat...

Fig. 9.4. Densitometer traces of stained poly(rA) zones after electrophoresis in 2.4% gels, a) Typical unfractionated sample, b) Fractions prepared by salt precipitation, c) Fractions made by preparative electrophoresis. The broken line is the profile of tRNA. Intensities are normalised at the peak. Mobilities are relative to bromophenol blue. The arrow indicates the end of the gel (from Finder and Gratzer 1974).

Fig, 10.12. a) Kinetics of cleavage of SV40 DNA by an E. coli B restriction enzyme as measured by gel electrophoresis of substrate (I) and products (IIB and IIIB). b) Use of gel electrophoresis as a fingerprint to identify the products of cleavage of the parent SV40 DNA (top) and of the fragment IIIB (bottom), by H. influenzae restriction nuclease (Adler and Nathans 1973). Patterns represent densitometer tracing... 

Fig. 10.—Densitometer tracing of the radioautograph of Fig. 9. The 5-dextrin shows as a clearly resolved peak the e-dextrin area appears only as a very weak but reproducible peak or shoulder against the background.

Figure 2. (a) Calculated dilTraction functions for several cluster models and a given number of atoms N. Lower curve represents Ar atomic scattering s = (4n/X)sin(6/2) is the diffraction parameter with 6 the diffraction angle and X the electron wavelength, (b) Densitometer traces of photographic plates recorded for several Ar inlet pressures. 

Figure 9.13. Densitometer trace from a stained electrophoresis gel.

The densitometer trace is used to measure peak positions (migration distance) and purity or relative concentrations of components by integration of the areas under the peaks. Modern densitometers perform this operation automatically. For quantitative work, overloading of the gels should be avoided, since this leads to very concentrated sample zones that may inhibit proportional staining and leads to underestimates of sample concentrations. 

Fig. 25. Densitometer tracings and starch-gel pattern of a patient with cirrhosis of the liver. Upper gel and tracings were obtained in the presence of n-phenylalanine applied with substrate to the gel lower gel and tracings were obtained in the presence of L-phenylalanine plus substrate. The direction of migration is from right to left. Note that the intensity of the slow-moving bands is reduced both visibly and by densitometry in the presence of L-phenylalanine. [Reproduced through the courtesy of Stolbach et al. (S49)].

Another early method used to monitor the laser pulse was the three photon fluorescence (3PF) technique. ( 8, 9) The advantage of 3PF over TPF is two-fold the contrast ratio is 10 1 for 3PF as opposed to 3 1 for TPF and in addition to temporal information about the pulses available by TPF, 3PF also provides pulse shape information.(10-13) This additional information is obtained because the third-order correlation function which relates the 3PF intensity to the pulse Intensity includes dependence upon the phase of the pulse frequency components.(11) Again, the resulting fluorescence is photographed, and a densitometer trace is made to determine fluorescence intensities. Azulene is an example of a molecule which has been studied quite extensively.(14-20) Typical data are shown in Figure 2. 

Fig. 4. Axial densitometer traces of tomographic sections shown in Fig. 3...

Normal and reverse-phase thin-layer chromatography (TLC) chromatograms are quantitated using a dual-wavelength scanning densitometer. Trace levels of organics in a mixture are separated and detected using UV-visible, reflectance, or fluorescence modes. Hydrazine, for example, can be analyzed for trace components on polymeric materials, determined to a 50-ppb or even lower level via established official (i.e., ASTM, USP) analytical procedures. TLC plates can be scanned unattended and quantitated automatically. The technique has been found to be particularly useful for compositional analysis, since individual component spots can be collected for subsequent spectral analysis or other available analytical techniques. 

Figure 476 Densitometer trace of the fringe pattern in a Fizeau wavemeter [185]...

Fig.5.7. The carbon K emission spectrum from the CO2 molecule. To the left the photographic plate and a corresponding densitometer trace are shown. Calculated spectra are shown to the right, illustrating the sensitivity of the spectrum to the C-O bond length [5.8]...

G Herzberg. Molecular Spectra and Molecular Structure, II. Infrared and Raman Spectra of Pola-tomic Molecules. New York Van Nostrand Rinehold, 1944. (Although this text does not present a description of instrumentation, it is easy to find examples of photographic images of spectral lines and what appears to be densitometer traces of these images.)... 

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