Total appearance

It can therefore be deduced that nifedipine at this concentration in the Eudragit microspheres was present in either a molecular dispersion or a solid solution state. This was also confirmed by the SEM analysis. It can be seen from Figs 1 and 3 that microspheres containing up to 5% nifedipine had very smooth surfaces. There was no evidence of macroscopic pores. Formation of fine nifedipine crystals seemed to have no effect on the surface structure of the nifedipine microspheres when the drug payload was 4.8% (w/w). However, three microspheres did not appear totally spherical. 

Most of the present discussion has been concerned with applications of REPs within the framework of otherwise essentially orbital-based calculations. On the other hand, a recent application 110) involved a quantum Monte Carlo (QMC) procedure. [A useful overview of Monte Carlo electronic structure work has been given by Ceperly and Alder 111). ] Currently, QMC offers little, if any, competition for conventional calculations in that the computer time required to reduce statistical errors to acceptable limits increases rapidly as a function of atomic number and is excessive for all but the smallest systems. Recent fluorine calculations required nearly 100 hours of supercomputer time 112). Although, on the surface, it would appear totally impractical, the appeal of this approach in the context of heavy-element work is its avoidance of extensive basis sets and enormous configuration expansions that plague present studies. 

Furthermore, the radical cation (37 ), produced by electrolysis and/or by the use of one-electron-oxidizing agents, appears totally inert vs triplet molecular oxygen, envisaging, also in this case, an inefficient Barton-type reaction. The whole of these complex results, of course, induce an easy question what factors control whether radical cations, chemically and/or photochemically generated, react with oxygen species or not ... 

While optical methods remain the favored means of analysis in both flash photolysis and pulse radiolysis, other methods of detection have been used with great effectiveness from time to time, including conductivity and ESR spectroscopy. The latter technique, in association with flash photolysis in particular, has led to the observation of ESR signals with anomalous intensities, for example, appearing totally in emission, a phenomenon described as chemically induced dynamic electron polarization or CIDER... 

Among numerous problems of cryogenic engineering there is the one of electrical conduction from an external room temperature source into a low temperature environment. For currents over a few amperes the problem is one of providing electrical conductors of suitable current carrying capacity without introducing excessive thermal conduction. In working at temperatures of liquid helium, the thermal losses quickly result in substantial boil-off. To conduct currents of several hundred amperes would appear totally impractical. 

Thus, it goes without saying that just on this criterion of embedded mass, certain solutions (flywheel, supercapacitors) appear totally umealistic. However, does this mean we need to dismiss them totally out of hand The answer is obviously no, as will be explained in the following sections. 

Although they appear totally different, the two strategies are equivalent. Both are correct under variational aspects and lead to exactly the same results. This can be understood by realizing that the periodic update of the one-electron Hamiltonian is nothing else than the update of the Fock-matrix, and that the final energy correction for the polarization costs is equivalent to the correction for double counting of the electron-electron interactions in the SCF procedure. 

Consider an AX system subject to this experiment. The spectrum will show no splittings, for it is taken with decoupling. The amplitude of the line will oscillate with t. In particular, for t =11]q- this signal will appear totally inverted. On the other hand, a... 

Figure 4 Scanning electron micrograph of a normal guinea pig trachea treated as in Figure 3. Small partieles appear totally submerged beneath the mucous layer. Note the Saran-like thin mucous sheet partially covering the large microsphere (arrow) bar = 20 i,m. (From Ref. 80.)...

---