Stepwise methods

Using a stepwise approach, the method of calculating thermodynamic (reversing) and isokinetic baseline (non-reversing) signals is different from the methods given in the previous 

There is also a step-based equivalent technique founded on linear-response theory. This has been presented by Schick and co-workers [19] and is formally equivalent to the real and imaginary heat capacities generated by modulation at a single frequency. In principle, it is therefore possible to apply a Fourier transform to step-scan type data and break down the overall response into heat flow responses to a series of sinusoidal temperature modulations. 

In this case, the slope of the initial step is important as this contains the high-frequency information. Any phase differences observed between stimulus and response and not caused by the DSC instrument itself will invalidate the simple reversing/non-reversing methods, but are coped with in linear-response theory. 

---

Synthesis. The method of synthesis for Methylene Blue described in reference 14 is stiU the stepwise method of choice for thiazine dyes. /V,/V-Dimethy1-y-pheny1ene diamine [99-98-9], CgH22N2, reacts with sodium thiosulfate [7772-98-7] to form the thiosulfonic acid which condenses with /V, /V-dimetby1 ani1 ine [121 -69-7], CgH N, in the presence of sodium dichromate [10588-01-9] to the indamine, then with copper sulfate [18939-61 -2] and sodium dichromate to Methylene Blue (26). 

The procedure described for the synthesis of methylenecyclopropane is patterned after the method reported by Caubere and Coudert. Methylenecyclopropane is also available from the stepwise method described by Kdster and co-workers. ... 

Fair recommends this method rather than his stepwise method given in the article, because it avoids increments of calculations but is sufficiently reliable for most design cases. This procedure is duplicated by permission. ... 

In Sec. 128 it was found that the vacant proton level of indicator 2 lies at 0.192 electron-volt below the occupied level of (HaO)+ in dilute aqueous solution. Using the successive increments listed in the last column of Table 39, we find, counting upward, that the value for indicator 5 is —0.052, referred to the same zero of energy. Proceeding by the same stepwise method to No. 6 we find for the energy of the vacant proton level the positive value +0.038. This still refers to the occupied level of the (II30)+ ion in dilute aqueous solution. It means that work equal to 0.038 electron-volt would be required to transfer a proton from the (H30)+ ion in very dilute solution to the vacant level of No. 6 in the concentrated acid solution in which the measurements were made. A further amount of work would be required to transfer the proton from the occupied level of No. 6 to the vacant proton level of one of the H2O molecules in the same concentrated solution. This is the situation because, as mentioned above, the changing environment has raised the proton level of the (HaO)+ ion relative to that of each of the indicator molecules. 

Principal component analysis (PCA) of the soil physico-chemical or the antibiotic resistance data set was performed with the SPSS software. Before PCA, the row MPN values were log-ratio transformed (ter Braak and Smilauer 1998) each MPN was logio -transformed, then, divided by sum of the 16 log-transformed values. Simple linear regression analysis between scores on PCs based on the antibiotic resistance profiles and the soil physico-chemical characteristics was also performed using the SPSS software. To find the PCs that significantly explain variation of SFI or SEF value, multiple regression analysis between SFI or SEF values and PC scores was also performed using the SPSS software. The stepwise method at the default criteria (p=0.05 for inclusion and 0.10 for removal) was chosen. 

Finally, in the stepwise method of constructing the final state of reaction 2.1, we can consider that the solution of 1 mol of water in pure water preceded the... 

Figure 12.10 The fit of the MLR model for c s-butadiene content in styrene-butadiene copolymers that uses four selected x-variables. The four variables were chosen by the stepwise method.

A systematic stepwise method for numerical integration of a rate expression [indeed, of any differential equation y = f(x,y) with an initial value y(Xo) = Vo] to determine the time evolution of the rate process. See also Numerical Computer Methods Numerical Integration Stiffness Gear Algorithm... 

STM The tunneling current between a metallic tip and a conducting substrate that are in very close proximity but not actually in physical contact. This is controlled by piezomotors in a stepwise method. 

One astute way to obtain macrocyclic systems with TTF is the stepwise method of deprotection/alkylation of cyanoethyl-protected TTF-thiolates. With this method molecular units can be built but with the precaution of preserving one cyanoethyl group in order to be able to iteratively proceed with the oligomerization. Combining such units, larger units can be produced. An example of a TTF dendrimer containing 21 TTFs is shown in Fig. 2.15 (Christensen et al, 1998). Here only the main philosophy of the synthesis is discussed. 

The latter stepwise method is the method of choice for the production of the commercially important 1 2 chromium complexes having only one sulfonic acid... 

An alternative shorter four-step procedure to prepare bis-TBs 41, 42, 43 and 44 has been reported (Scheme 9), and also tris-TB 51 from diaminobenzenes 45, 46 and 47 and from 1,3,5-triaminobenzene 49 (02CCC609, 05MI1) (Scheme 10). Moreover, the simultaneous formation of the TB units on a central core may also be used for the preparation of multi-TB systems. It may seem that this methodology is limited only to the preparation of symmetrical oligo-TB derivatives. However, another report demonstrated that the simultaneous approach is also applicable to unsymme-trical bis-TB (04EJ01097) (see Scheme 8, pathway B). The overall yield in the preparation of 40 (Ri = CH3, R2 = N02) was lower than that of the original stepwise method. 

Complex 12 can be also synthesized via a stepwise method (Scheme 12.8) that evidences a reversible oxidative addition of the phosphole P-Ph bond on Pd(0) centers [25b]. 

BB)n— Peptide/ AA—Resin BB building block, AA amino acid FIGURE 3.2 Convergent method and stepwise method. 

Synthetic access by stepwise method to glycopeptides molecules requires flexible solution- and solid-phase combinatorial strategies. The selected... 

The adaptation of this procedure in solid phase allows expansion of the easy and automated access to novel glycosylamino acid building blocks required for chemical libraries construction, not only by convergent, but also by stepwise, methods. 

The reaction of heteroaryl halides with Rieke Mg, performed in the presence of electrophiles (Barbier conditions), affords sometimes better results than the usual stepwise method (Scheme 4). ... 

To illustrate the stepwise method for reactions involving strong electrophiles, we will develop a mechanism to account for the following cyclization ... 

In learning about NMR spectra, we have seen that chemical shift values can be assigned to specific types of protons, that the areas under peaks are proportional to the numbers of protons, and that nearby protons cause spin-spin splitting. By analyzing the structure of a molecule with these principles in mind, you can predict the characteristics of an NMR spectrum. Learning to draw spectra will help you to recognize the features of actual spectra. The process is not difficult if a systematic approach is used. A stepwise method is illustrated here, by drawing the NMR spectrum of the compound shown here. 

---