Manual mixing

Fig. 5. Multiple phases in the reduction of xanthine oxidase by xanthine at pH 8.2. Intensities of the Rapid (circles) and Slow (triangles) molybdenum EPR signals expressed as electron/mole enzyme (i-e. per 2 atom Mo) are plotted as a function of time. Note the changes in the time scale. Rapid freezing was used for reaction times (at 22°) up to 1 sec. and manual mixing for longer times (at 25°) enzyme concentrations (immediately after mixing) were 0.09 mM and 0.13 mM respectively. The enzyme had Activity/A45o 125 corresponding to 63% of active enzyme and 20 mole xanthine/mole enzyme was used. (Data from ref. 67.)...

In a thermite process to produce chromium metal, the mechanically-mixed ingredients were ignited in a large crucible and the reaction proceeded smoothly. When the mixer broke down, manual mixing was used but gave poorer dispersion of the constituents. An explosion after ignition is attributed to a high local concentration of sodium chlorate and aluminium powder in the mixture. 

Unless you have been employed in the automobile refmishing or other business where painters manually mix two-component polyurethane paint systems, it is unlikely that you will be exposed to large amounts of HDI. 

On the other hand, manually mix epoxy resin and hardener in the ratio 20 3 (w/w) using a spatula. When the resin and hardener are well mixed, add the graphite powder (particle size 50 pm) in the ratio 20 80 (w/w) and mix thoroughly for 30 min to obtain a homogeneous paste of graphite-epoxy composite. Place the resulting paste into the cylindrical PYC sleeve, onto the copper disk. 

Signal averaging is almost always required for time-resolved measurements. Signals are small because of the relatively low number of scattered photons resulting from the short exposure times employed for manual mixing or stopped flow measurements or the small sample volumes associated with continuous flow mixers. 

PEEK fine powder is manually mixed with the SWCNTs. 

Add 1.0 mL of the spiking solution in Section 5.18 and Table 11 to the aliquot. Manually mix the sample to distribute the spiking solution, and let the aliquot equilibrate for one hour. 

Powder, granules Powder manual mixing using mortar and pestle Recombinant hGH Chitosan In sheep Relative bioavailability of hGH from powder and granules have been 14 and 15%, respectively 77... 

The search for an enzymatic activity that would catalyze prolyl peptide bond isomerization began soon after the proposal of the proline hypothesis. The success came in 1984, when Fischer and co-workers discovered a peptidylprolyl m—tram-isomerase activity in porcine kidney and other tissues by an assay that is based on the conformational specificity of chymotrypsin. This protease cleaves the 4-nitroanilide moiety from the peptide glutaryl-Ala-Ala-Pro-Phe-4-nitroanilide only when the Ala-Pro peptide bond is in the trans conformation. In aqueous solution 90% of the molecules are trans in the assay peptide and only 10% are cis. Therefore, in the presence of a high concentration of chymotrypsin, 90% of the hydrolysis reaction occurs within the dead time of manual mixing. Hydrolysis of the remaining 10% is slow, limited in rate by the cis — ... 

As shown in Table 4, typically, a stock monomer solution (for 4 to 5 runs) is prepared in a 50-mL round-bottomed flask by mixing toluene (21.0 mL), IBVE (1.50 mL), and carbon tetrachloride (1.50 mL). To 10-20 mL glass tubes are distributed 4.0-mL portions of the monomer solution, and they are cooled to -78° C in a methanol bath. Separately in 50-mL round-bottomed flasks, solutions of HC1 (50 mM) and ZnCl2 (10 mM) are prepared by diluting their commercial solutions (1.0 M in diethyl ether) with toluene the HC1 solution should be prepared and kept at -78° C. These diluted solutions are then added, first HC1 and then ZnCl2, to the monomer solution at -78° C with vigorous manual mixing, and the tern-... 

Figure 6. Equilibrium unfolding of low molecular weight urokinase observed by mtrinsic tryptophan fluorescence using manual mixing (upper panel) and continuous flow analysis (lower panel). Samples for manual analysis equilibrated for >1 hr before reading. The vertical arrow in the upper panel indicates fluorescence signal at 365 nm from excitation at 290 nm. Data in Tower panel was measured using die same excitation and emission wavelengths. Both sets of measurements indicate two transitions in fluorescence quenching. Manual measurements were made with a Shimadzu RF-5000U spectrofluorometer.

In Figure 6 the equilibrium denaturation in urea of low molecular weight urokinase is performed by both manual mixing and automated equilibrium denaturation and... 

For the reactions reaching completion in less than a minute, the manual mixing of the reagents and the initiation of data acquisition would overlap with the chemical reaction. A number of rapid mixing and relaxation techniques are available to cover these shorter timescales, as described below. 

Using a paddle with sufficient manual mixing will suffice for the initial preparation of a dilute solution, although it will not be sufficient to prevent stratification. Therefore, a mechanical mixer is preferred. Mixers are available in various sizes, with shafts and propellers made of various materials to meet chemical-resistant requirements for different fluoride chemicals. Depending on the size of the mixing tank, a fractional horsepower mixer with a stainless-steel shaft and propeller will be satisfactory for sodium fluoride solution, and a similar mixer with a corrosion-resistant alloy or plastic-coated shaft and propeller will handle fluosilicic acid (15). 

Compared to manual mixing, this proceeding bears the following advantages ... 

For the processing in workshops, laboratories or in the private sector, automated facilities are usually too expensive. Here, manual mixing of the adhesives is indicated. To avoid possible mistakes, it is advisable to observe the following instructions ... 

The internal equilibrium constant can be measured after finding conditions under which all of the substrate and product will be bound to the enzyme. This is done by working at concentrations of enzyme in 5- or 10-fold excess of the dissociation constants for each substrate. Accordingly, the ratio of [P]/[S] measured will reflect the ratio of [E-P]/[E-S] = Kim- The time required for the reaction to come to equilibrium can be approximated from the relationship /tobs itcai + kai to provide a minimum estimate of the rate of reaction at the active site. Usually the time calculated will be in the millisecond domain, but incubation for S sec is more convenient for manual mixing and usually no side products are formed on this time scale. Although in some cases it may be difficult to obtain concentrations of enzyme in excess of the dissociation constants for the substrates and products, the quantitation of the product/substrate ratio can be done quite accurately thanks to the fundamental property of enzyme catalysis that leads to an internal equilibrium constant close to unity for most enzymes (78-20). 

Manual Mixing When the mobile phase is to be prepared manually, the organic portion and the aqueous portion should be independently measured out using measuring cylinders or by weight where appropriate. Both phases should then be added together in a separate HPLC solvent bottle and... 

---