Pretreatment conditions

Cellulase and all chemicals used in this work were obtained from Sigma. Hydrolysis experiments were conducted by adding a fixed amount of 2 x 2 mm oflSce paper to flasks containing cellulase in 0.05 M acetate buffer (pH = 4.8). The flasks were placed in an incubator-shaker maintained at 50 °C and 100 rpm. A Box-Behnken design was used to assess the influence of four factors on the extent of sugar production. The four factors examined were (i) reaction time (h), (ii) enzyme to paper mass ratio (%), (iii) amount of surfactant added (Tween 80, g/L), and (iv) paper pretreatment condition (phosphoric add concentration, g/L), as shown in Table 1. Each factor is coded according to the equation... 

Pretreatment condition TOClppm] Reducing sugar Fg/ll Total sugar fg/ll... 

The pretreatment conditions were the same as those for IR study of adsorbed pyridine. The sample pretreated in a vacuum was exposed to ca. 300Torr D2 at different temperatimes for 1 h. After cooling to room temperature, the sample was outgassed for 10 min prior to TPD run. TPD was run at a heating rate of lOK min 1, and the desorbed gases were analyzed by mass spectrometry. 

The catalytic activity of an electrode is determined not only by the natnre of the electrode metal (its bulk properties) but also by the composition and stmcture of the snr-face on which the electrochemical reaction takes place. These parameters, in tnm, depend on factors such as the method of electrode preparation, the methods of snr-face pretreatment, conditions of storage, and others, all having little effect on the bulk properties. 

Although no explanation for the underlying mechanistic details can be given, the support and pretreatment conditions clearly have a strong effect on catalyst performance. Highest mean rates are obtained with reduced catalysts based on silica whereas the precursor seems to have only a negligible effect. 

Fig. 1 a Mean quantitative nicotine-appropriate responding and mean EM selected subjective responses across nicotine generalization doses collapsed across aU active mecamylamine pretreatment doses (5-20 mg filled circles) and across two no mecamylamine sessions (0 mg, retest open circles) in the preliminary study n = 3). Subjective ratings at baselines 1 and 2 (BLl, BL2) were obtained at the beginning of each session and just before the first nicotine generalization dose trial (2h after pretreatment), respectively, b Mean EM nicotine-appropriate responding across nicotine generahzation doses as a function of pretreatment condition (oral placebo, open circles ... 

Clements, J. and Beitz, A. (1985) The effects of different pretreatment conditions and fixation regimes on serotonin immunoreactivity a quantitative light microscopic study. J. Histochem. Cytochem. 33,778-784. 

For optimizing pretreatment conditions, treat a series of tissues (sectioned from the same tissue block) with different concentrations of proteinase K (5, 10, 15, 20, 25, 30 pg/mL) and incubate for 15 min at 37°C in the humidity chamber. 

Soils that contain metal contaminants require simple pretreatment conditioning. 

The range of the gzz values is shown clearly by a comparison of the results for the NaY and NaX zeolites. Since the migration of Na+ ions is related to the presence of water (76), it is likely that the type of precursor (Na4)4+ -(H20)x complex formed after a proper degree of dehydration (278) will be strongly dependent on the pretreatment conditions. This will be reflected in the gzz values of the OJ produced during y irradiation by electron transfer from the precursor (278). It is also likely that the OJ can migrate after its formation as shown by Kasai and Bishop (264). These authors (272) have detected a superhyperfine interaction from Na nuclei (I = ) in the EPR spectrum of OJ formed in Na-reduced NaY zeolite and characterized by gzz = 2.113. This value is very close to those observed for alkalisuperoxides trapped in krypton matrices (Ref. 44, Appendix A). 

The IR data observed for oxygen adsorbed on oxides depend on a number of factors, such as the nature of the oxide (20a). the pretreatment conditions (20b), and the temperature of oxygen adsorption (149a), and this results in a wide range of frequencies. 

The one-step synthesis of nitroso compounds by selective reduction of the corresponding nitro compound is a commercially interesting route. Some relevant information on this reaction can be already found in the literature. So. for example, Kishi161 studied the adsorption of nitrobenzene on Fe/Ni(100) surfaces with different pretreatment conditions and found that the extent of preoxidation of the Fe/Ni surface controls the dissociative chemisorption of nitrobenzene into nitrosobenzene, C6H5NO(ads), and nitrene, C6H5N(ads). The dissociation of nitrobenzene into nitrosobenzene takes place when the surface is oxidized to an Fe304-like species. This species appears, in contrast to the pure Fe/Ni(100) surface, to be unable to dissociate nitrosobenzene further into nitrene. 

In order to understand better these interesting systems without complications that might arise due to different preparation procedures, we compared oxygen-treated WC and Mo2C prepared by similar reduction/ carburization procedures from their respective oxides. The effects of pretreatment conditions were also studied. An attempt was made to correlate the kinetic behavior of these catalysts in n-hexane-H2 reactions with their physical properties obtained from X-ray diffraction (XRD), CO chemisorption, temperature-programed reaction (TPR) with flowing H2 or He, temperature programed desorption (TPD) of adsorbed NH3, and X-ray photoelectron spectroscopy (XPS). 

We can define pretreatment as the initial conditioning period whereby a corrosion inhibitor is applied to the metal surfaces of the cooling system. Pretreatment conditions must be conducive to the rapid formation of the protective barrier. The conditioning procedure should involve (1) the cleaning and preparation of metal surfaces, and (2) the actual application of higher than normal inhibitor concentrations. 

Figure 12, derived from the results of Misono and Selwood (22) and of Ng and Selwood (23), shows A/c for a-Cr203 as a function of extrinsic field up to about 18 kOe at 311.2 K. For a sample of surface 6.0 m2 g l and at atmospheric pressure, k0 at 311.2 K was about 9.8 /umol m-2 s l. This rate varied somewhat, as expected, with small differences in pretreatment conditions. The rate was also sufficiently sensitive to the temperature of measurement, especially near TN, as to require control to 0.1 K. 

Certain correlations are possible but it must be kept in mind that comparisons of activity in heterogeneous catalysis are likely to be treacherous. Minor differences in surface pretreatment may make major differences in properties. Nevertheless, it is clear that there are recognizable patterns of extrinsic field effects. The several kinds are shown in Fig. 22 wherein AkH is plotted against H (log scale). The curves drawn are meant to be representative, but except for relatively minor details, all of the samples studied to date fall into one of the six patterns shown. This covers over 30 different catalyst preparations, a variety of temperature-sensitive magnetic phases, and various pretreatments. Figure 22 shows one example of catalysts found to have the indicated kind of field effect. Pretreatment conditions are stated in Table IV which includes all samples on which measurements have been made. Pretreatments are abbreviated as follows (H2773q298) means that the sample had been heated in hydrogen for an hour or more at 773 K and then cooled rapidly to 298 K. One or two temperatures at which each A k pattern has been observed are also shown in Table IV. 

Thus, it was observed that the first-order rate constants (/q) for nitrate reduction by untreated Fe° increase due to the pretreatment of iron metal with HC1 however, observed increases in the rate constant for nitrite reduction have been relatively small under similar acid pretreatment conditions. During the first 12 hr, the rate constant for nitrate reduction showed a gradual decline, and this decline seems to have been clearly influenced by the presence of chloride. The reaction rate constants for nitrate and nitrite reduction by untreated Fe° turnings are directly dependent on the concentration of Fe° used, ranging between 69.4 and 208.2 g/L thus /c, and k, increase linearly with increases in the surface area of the untreated iron. Table 13.8 demonstrates that acid-treated Fe° is more reactive than its untreated counterpart. 

Urea (0.01 M), sodium carbonate (0.01 M), magnesium chloride (0.01 M), or distilled water can be used as microwave fluids to obtain similar results in terms of both sensitivity and intensity of the hybridization signal. Alternatively, 10 mM citrate buffer (pH 6.0) can be used as the microwave fluid. The major role of these fluids is to mediate high temperature effects, which is confirmed by the achievement of a good hybridization signal using distilled water. Note that pretreatment conditions must be optimized for every tissue type and for every cell type in a given section. 

---