Cell preparation measurements

Samples were prepared by using a vacuum manifold to fill the gas cell. After measuring the total pressure, the absorbance of the sample at 2170 cm- was measured. Results are reported as %CO (Pco/ftot)- Five exhaust samples were obtained from a 1973 coupe, yielding the following results... 

Fig. 8.2 Gel filtration on a column of Sephadex G-100 at pH 8 (both panels) of the crude extract of Gonyaulax polyedra cells prepared at pH 8 (upper panel) and prepared at pH 6 (lower panel). The activities of the 35 kDa and 130 kDa luciferases are measured by the addition of an excess of luciferin at pH 6.3 ( ) or at pH 8(A). The activity of the luciferin-bound LBP (luciferin-binding protein) in the upper panel is measured after the addition of an excess of 35 kDa luciferase at pH 6.3 ( ). In the lower panel, the LBP activity can be obtained by the addition of an excess of luciferin at pH 8, followed by the removal of unbound luciferin with a small column of Sephadex G-25 before the luminescence assay of bound luciferin at pH 6.3 (see the Section 8.2.8). The Overlap in the upper panel is the light emission resulting from the mixing of an aliquot of the fractions with pH 6.3 buffer. From Fogel and Hastings, 1971, with permission from Elsevier.

Electrophysiological Experiments. Guinea pig myocardial cells prepared as described previously 24) were superfused at 37 C with a Tyrode solution. Electrical properties of the myocytes were examined by the patch-clamp methods (25) using fire-polished pipettes. The current was measured by means of a patch-clamp amplifier, stored on the tape through a digital PCM data recording system, and analyzed with a computer. 

This can be carried out in vitro (in brain slices, cultured cell preparations) or in vivo and involves penetrating the experimental tissue with a carbon-fibre electrode of 5-30 pm in diameter (Fig. 4.9). This serves as an oxidising electrode and the Faradaic current generated by the oxidation of solutes on the surface of the electrode is proportional to their concentration. Obviously, only neurotransmitters which can be oxidised can be measured in this way so the technique is mainly limited to the study of monoamines and their metabolites. The amplitude of each peak on the ensuing voltammogram is a measure of solute concentration and individual peaks can be identified because different... 

The solid or dashed lines correspond to modified Michaelis-Menten kinetics assuming activation with one and inhibition with two molecules bound according to Eq. (15). Solid symbols represent average value of n = 3-5 parallel measurements made with one single cell preparation. (Adapted from Ref. [58].)... 

The PV efficiency of the CIGS2 cell prepared on glass with transparent conducting back contact, as measured at the NREL, was 5.95%. Calculated PEC efficiency of two such PV cells... 

Before further testing and to confirm that the compounds are cytotoxic rather than merely interfering with the Alamar blue indicator dye, they are re-bioassayed using two other indicator dyes. Calcein-AM is a fluorescent dye that measures changes in cell mem brane permeability, an indicator for one of the penultimate steps of cell death, uci e e measures the amount of adenosine triphosphate (ATP) synthesis in a chemilurmne assay. For some compounds, cell death was also confirmed by microscopic exami Papanicolaou-stained cell preparations.11... 

A second way of expressing the same information is to give electrode potentials (Table 6-8). Electrode potentials are also important in that their direct measurement sometimes provides an experimental approach to the study of oxidation-reduction reactions within cells. To measure an electrode potential it must be possible to reduce the oxidant of the couple by flow of electrons (Eq. 6-62) from an electrode surface, often of specially prepared platinum. 

Fig. (5). Effects of Some OGs on Primary Cultured Rat Hepatocytes injured with CC14 Effects of glycyrrhizin (GL, triangles), kaikasaponin III (2 1, Kaika III, circles) and soyasaponin I (1, Soya I, squares) on CCI4 (SmM)-induced cytotoxicity in primary cultured rat hepatocytes. The marker of liver injury is the aspartate aminotransferase (AST), measured in IU (International Units)/ . Data are the mean S.D. for three independent cell preparations.

Significant advances in studying secretion were obtained with help of perme-abilized cell preparations, e.g., cracked PC12 cells that allows direct biochemical access to intracellular release machinery (Klenchin et al., 1998 Martin and Grishanin, 2003). Similar approaches were relatively unsuccessful in neuronal preparations, possibly due to the complexity and small size of synaptic terminals. However, better-controlled permeabilization (using bacterial toxins) may be a promising approach to develop reliable and reproducible assays to measure neurotransmitter release in these preparations. 

Equations (47)-(50) indicate how thermodynamic quantities can be obtained from cell potentials measured under standard conditions. However, standard states are hypothetical states (e.g., infinitely dilute behavior at 1.0 m concentration), which cannot be prepared in the cell. As a result, an extrapolation procedure is used to find 8° from measured cell voltages as a function of concentration. From Eq. (47), we write the dependence of 8 on the concentration of the electrolyte in the form... 

The combination of Mg and Al has been the most frequently studied, with a variety of Mg/Al ratios and different charge-balancing anions. Figure 9.3 shows the variation of the hexagonal unit-cell parameters measured for MgAl(C03) LDHs prepared with systematically varied Mg/Al ratio from 1.0 to 3.5, via the constant pH (=10) coprecipitation method [36]. The a-parameter... 

The same technique is applied for the determination of the pressure in the combustion chamber. The pressure cell must be attached to the previously prepared measuring points on the combustion chamber. 

For turbidity measurements, a stock solution of desired mole ratio of sodium lauryl sulfate to BC-840 was prepared on a weight basis. The stock solution was diluted volumetrically to a series of different concentrations. These diluted solutions were allowed to stand overnight for equilibration of micelles. Solutions were filtered four times under pressure through HAWP 0.25 filter directly into scattering cells for measurements. 

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