Refining solutions

As this soln is usually acidic (pH 4.2-4.6), add slowly 25 to 30 g NaOH in dil aq soln. NaOH serves to neutralize all acid either occluded or that due to hydrolysis of lead nitrate. An excess of NaOH must be avoided because it tends to produce elongated crysts of LA which are very sensitive. Add to the stock soln 9 lb(ca 4.08 kg) potato dextrin previously dissolved in about 100 1 of water and then bring the soln to 7.325 0.07% Pb (NOj)a content. b)Prepare the stock soln B by diluting with treated w the refined solution (contgca 27% NaNs),delivered from the Sodium Azide (qv) plant to 3.175 ... 

Because of the approximations involved in this analysis, the thermodynamic results have to be considered with caution. This is not only due to a rather crude analysis of the electrostatic effects but also, and this is a general problem, to the neglect of solvation in the molecular mechanics refinement. However, the structures presented in Fig. 9.6 are valuable because they are based not only on the structure optimization by molecular mechanics but also on spectroscopic data. This example is therefore instructive for two reasons first, it demonstrates that, depending on the study, the often-neglected electrostatic effects may be of considerable importance. Second, not only may experimental observables help to refine solution structures, they can prevent a wrong conclusion. As in this example, the combination of experimental data with molecular mechanics calculations is often the only way to get reliable structural information. 

McCallum, S. A., and Pardi, A. (2003). Refined solution structure of the iron-responsive element RNA using residual dipolar couplings. J. Mol. Biol. 326, 1037—1050. 

The results indicate that Raman spectroscopy can be useful in the mining industry. All the major species in metal refining solutions can be identified at concentrations below typical values. A distinct advantage is apparent in studying aqueous solutions of this type using Raman spectroscopy because... 

The full relaxation matrix approach for distance determination from 2D NOESY data has been used in many groups to refine solution structures of DNA, including mismatched duplexes, variously chemically modified duplexes, complexes with small molecules, and so on.93 174 176 178-195 However, there are fewer RNA structures... 

Baumann, H., K. Paulsen, H. Kovacs, H. Berglund, A.P.H. Wright, J.A. Gustafsson and T. Hart. Refined solution structure of the glucocorticoid receptor DNA-binding domain. Biochemistry 32 13463-13471, 1993. 

Schwalbe, H., Grimshaw, S.B., Spencer, A., Buck, M., Boyd, J., Dobson, C.M., Redfield, C., and Smith, L.J. (2001). A refined solution structure of hen lysozyme determined using residual dipolar coupling data. Protein Sci. 10, 677-688. 

Sulfur Compounds Present in Refining Solutions. Acid and alkaline derivatives are discussed separately. 

It is interesting to observe that, even if the coefficients d in the original approximate eigenelement D = Bd are determined by solving the equations (1.49) and (1.50) involving double commutators, the refined solutions (2.40) and (2.49) lead to situations where... 

Jourdan, M., Garda, J., Defrancq, E., Kotera, M., and Lhomme, J. (1999) 2 -Deoxyribonolactone lesion in DNA refined solution structure determined hy nuclear magnetic resonance and molecular modeling. Biochemistry, 38, 3985-3995. 

Obtaining optically active compounds by chiral induction represents a more refined solution to organic chemists. 

Band L, Bertini I, Bren KL et al (1996) The use of peudocontact shifts to refine solution structures of paramagnetic metalloproteins Met80Ala cyano-cytochrome c as an example. J Biol Inorg Chem 1 117-126... 

Ciystallization is employed heavily as a separation process in the inorganic chemical industry, particulaiiy where salts are recovered from aqueous media. In production of organic chemicals, crystallization is also used to recover product, to refine intermediate chemicals and to remove undesired salts. The feed to a ciystallization system consists of a solution from which solute is ciystallized (or precipitated) via one or more of a variety of processes. The solids are normally separated from the ciystallizer liquid, washed, and discharged to downstream equipment for additional treatment. High recovery of refined solute is generally the desired design objective, although sometimes the crystalline product is a residue. 

In pH zone refining, solutes are not eluted as separated peaks but as contiguous blocks of constant concentrations, so that it is highly difficult to monitor the separation by means of a U V detector. Online pH monitoring is generally used, allowing the observation of transitions between solutes, since each zone has its own pH determined by the pA a and the solute concentration. The experiment was carried out in stop-flow mode. 

Refined solution structure of the 82-kDa enzyme malate synthase... 

---