Parallel experiments

Parallelversuch, m. parallel experiment, dupU-cate determination. 

When the reaction is performed at relatively low temperatures that prevent strong thermal decomposition of the alkali metal carbonate, the formation of C02 will be related only to the reaction and will indicate the stoichiometry of the process. Fig 8 presents mass loss isotherms of Nb02F - M2CO3 mixtures (in which M - Li, Na, K, Rb, Cs) that were subjected to thermal treatment in air at 850°C [84, 85]. It is important to mention that parallel experiments performed without the addition of Nb02F, resulted in alkali metal carbonate mass losses that were in the same order of magnitude as the measurement errors at temperatures below 850°C. 

In the analogous studies of the photolysis of sulfolane (31), the work of Honda and coworkers66 was carried out in the gas phase at 70-130 °C and established the formation of S02, ethylene, cyclobutane and acetylene as the major products, on mercury-sensitized photolysis. In considerable contrast, photolysis of sulfolane at 185 nm in the liquid phase67 produced ethylene( = 0.22), the sultine (32) (aqueous solutions of sulfolane, a sulfinic acid is also believed to be formed. The authors believe that both four-membered (33) and six-membered (32) sultines may be formed during these photolyses. Further work in this area would appear to be necessary to unravel the full mechanistic details. 

Our parallel experiments, in which subtilisin Carlsberg was used to promote hydrolysis of A-acetyl-A-benzyl arenesulfinamides, led to exclusive S-N bond breaking. However, the recovered substrates were racemic. Moreover, blank experiments showed that a spontaneous chemical hydrolysis contributed to the process to a much higher degree than that in the cases shown in Ref. 47. Hence, a conclusion was drawn that in our case the hydrolysis proceeded without involvement of the subtilisin active site Kielbasihski, P. Albrycht, M. Mikolajczyk, M. Unpublished results. 

One example showing a serious discrepancy of the frontier electron method was reported by Dewar H8,ii9). This is 10,9-borazaphenanthrene, and the value of / -B) was reported to have been calculated by the Pople method, but the parameters usyd were not indicated. Fujimoto s calculation by the Pariser-Parr-Pople method 120>, in perfect disagreement with Dewar s, gives the most reactive position as 8, which parallels experiment. The ambiguity involved in the integral values adopted seems to be serious, so that the establishment of parametrization for boron heterocycles is desirable. 

In a parallel experiment in which 25 g. of sodium peroxide was used, the precipitate was not the peroxide but evidently consisted of sodium />-nitroperbenzoate. 

The experiment, or preferably a number of parallel experiments, is carried out until the originally available readily biodegradable substrate and the fast hydrolyzable substrate are depleted. For typical domestic wastewater, this is... 

FIGURE 7.8. OUR curves of six parallel experiments with varying amounts of acetate added. 

TABLE 7.2. Process Parameters for the Six Parallel Experiments Shown in Figure 7.8. The Parameters are Calculated by Expressions (7.1)-(7.3) and the Procedure Outlined for Ksw... 

After reporting the initial parallel experiments, the authors report a pooled approach using a chemical encoding strategy (176 and 177, see Fig. 3). Both the palladium and the nickel systems were screened in the same reaction vessel. Upon reaction, two different sized beads of polyethylene were observed. Deconvolution indicated the larger polymer granules were from catalysis by the nickel catalyst. 

No increased incidence of neoplasms at any site was observed in Fischer 344 rats of either sex (50/sex/group) similarly exposed to commercial hexane in a parallel experiment (Bio/Dynamics 1995a). 

Lungarella et al. 1984). In a chronic-duration study in B6C3F, mice where exposure was to commercial hexane (51.5% M-hexanc) for 6 hours/day, 5 days a week for 2 years, a statistically significant treatment-related increase in hepatocellular neoplasms (adenoma and carcinoma) was observed among females exposed at 9,018 ppm (Bio/Dynamics 1995b), but not at 900 or 3,000 ppm. No increases were observed in male mice or in Fischer 344 rats of either sex exposed similarly in a parallel experiment (Bio/Dynamics 1995a). 

The enzymes used by these workers were cholinesterase, prepared from horse serum, and horse-liver esterase. Parallel experiments were carried out with twice crystallized ovalbumin, and with an aged, dialysed specimen of horse serum with negligible esterase activity. 

The inverse of the above experiments gave similar results (Whitlock and Stein, 1978). Trypsin-digested histones removed from HeLa core particles can subsequently fold DNA, although DNase I digests the resulting particles more rapidly than the untreated ones. Parallel experiments were performed for chicken erythrocyte core particles (Lilley and Tatchell, 1977). In all cases it could be concluded that it is the trypsin-insensitive carboxy-terminal regions of the histones which are responsible for the folding of the DNA in the nucleosome. 

Once you have established roughly linear pH gradient conditions for your cation and anion exchangers, conduct an experiment with sample. Follow this with a parallel experiment in which 0.05 M NaCl has been added to the buffers. If the proteins of interest are still retained in the 0.05 M NaCl experiment, conduct another pH gradient in 0.1 M NaCl. Collect and analyze fractions as in the previous experiments. 

The relative viscosity rj and storage modulus G were determined by Cirkel and Okada in experiments using a rheometer in oscillatory rotational mode and Couette sample geometry as a function of Nafion volume fraction, cp, and angular frequency, a>, for the acid and sodium forms at 25 °C. Parallel experiments... 

Besides homogeneous and uniform SAMs or polymer brushes, systems of tailored heterogeneity such as mixed monolayers of two or more compounds, gradients, block copolymer brushes etc. are now under investigation. Especially, the development of patterned surfaces offers the exciting possibility to perform multiple parallel experiments on a single substrate or cascade reactions. 

In a parallel experiment, the extent of the reaction a is measured using the partial heat to a particular time divided by the total heat of the isotherm plus the residual heat of a subsequent 10°/min ramp. Figures 5 and 6 show the observed relationship of In a and In t to a. As expected for a similar degree of advancement a, the ionic mobility a increases with temperature. Similarly for the same value of a, the dipolar mobility increases. An increase in dipolar mobility corresponds to a shorter relaxation time. Thus t decreases as temperature increases. Somewhat unexpected, both In a and In t exhibit a nearly linear dependence on a. Curvature in the In a and In t versus a plot is most pronounced for small values of a and at the highest temperature. There is no evidence of a break in the In <7 or In T dependence on a which would indicate gel. 

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