Visual counting

Sediment. Sediment is most commonly used as an operational check of filter efficiency and leakage, although some customers, especially those who iatend to melt the sugar iato clear solutions, write sediment restrictions. The measurement is normally done by passiag the 50% solution used for the color determination through a half black—half white filter pad and visually counting the white and black specks. 

When the frequency of bubble formation is very low (<200 bubbles per minute), the bubbles can be visually counted without the aid of any instrument. When the frequency is higher than this, other methods have to be employed. 

In a related experimental study, the relative effectiveness of all the above-mentioned decompression tables in reducing bubble formation within aqueous gels was evaluated quantitatively under rigorously controlled conditions specifically, visual counts were conducted of the bubbles formed in highly purified agarose gels (ref. 49,139) subjected to the different decompression schedules. 

The duration of the nucleation pulse at the given overpotential can be increased successively by equal increments until a linear relationship between number of nuclei and time is obtained. A second series of measurements is then performed at another overpotential. The technique, being based on visual counting, allows the determination of the nucleation rate on different crystallographic zones to be carried out. In other words, it enables differently active zones with respect to nucleation on the electrode surface to be distinguished [4.35, 4.36]. 

Since O2 uptake does not require the growth of colonies of bacteria needed for visual counting of plates, four hours or less of growth is sufficient for O2 uptake difference measurements to be made. Thus, test time probably can be reduced from 48 hours to 4 hours (neglecting sample preparation time, which would be similar for both). Further, plate-counting time and cost is eliminated, because differences in reversions are measured directly by the difference current output of the electrodes. In principle, the greater the current difference. 

Fig. 5 Results of the colony formation test. Each colony number was visually counted (n = 3). Normal culture (no extract) was used as a control. The colony number of each extract added culture was divided by that of the control. Each column and error bar indicates means and standard deviation, respectively. 1 SUS304 2 SS400 3 nickel coated 4 chromate conversion and zinc-coated SS400 5 nickel plate 6 chromium plate. p < 0.01 (Student t test)...

Using many different samples of parboiled rice, dried in the form of paddy or processed kernels under different conditions, it was possible to cover a wide range of percentages of broken kernels. It is remarkable that the estimates from the image analysis software matched very well measurements using both the ISO norm for HRY and the visual counting (Fig. 2.11). 

B16-BL6 cells (2 X lO ) were seeded with or without chitin derivatives into the upper compartment of Transwell chambers. Filters were precoated with either fibronectin (5 jxg) or laminin (5 mg) on the upper surface. After an 8-h incubation, the invading cells on the lower surface were visually counted. 

Figure 8 Dose-response of SCM-chitin III on haptotactic migration of tumor cells. B16-BL6 cells (2 X 10" ) were seeded on the filter precoated on the lower surface with 5 xg laminin. Various concentrations of SCM-chitin III were added into the lower compartment of a Transwell chamber. After a 6-h incubation, the migrant cells on the lower surface were visually counted. P > 0.001 compared with the control by Student s two-tailed r-test.

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