More Systematic Studies

More systematic study of the dynamics of radicals in solution should now be possible using CIDNP. Investigations so far reported have indicated that the rates of very rapid chemical reactions and other dynamic processes undergone by radicals can be measured in a crade way greater refinement should be possible. Special effects have been predicted for reactions in thin films (Deutch, 1972). Moreover the time-scale of polarization is such that the technique may prove capable of throwing new light on the dynamics of excited states. 

For a better comprehension, however, more systematic studies of dithiocarbamato and other complexes are necessary. 

While more systematic studies are still necessary to completely characterize all... 

The initial question was whether the active catalyst is copper metal, copper(I), or copper(II), because all metal precursors gave results. Without the proper control of the valence state and the ligand environment the selectivities for the copper catalysed cyclopropanations (or carbene insertion reactions) have remained low or inconsistent for a long period of time. It was only in the sixties that a more systematic study of these issues was started. Several divalent copper salts were successfully used, but Kochi and Salomon [1] showed with the use of Cu(I)OTf that most likely copper(I) was the actual species needed for this reaction. 

Environmental Fate. It is not known if 3,3 -dichlorobenzidine, like benzidine, is oxidized by clay minerals or if cations in water ean have the same oxidizing effect. 3,3 -Dichlorobenzidine does not appear to biodegrade easily, but the few studies in this area did not state the type(s) or concentrations of mieroorganisms used in eaeh study. More systematic studies with other organisms may prove useful. A reeent study (Nyman et al. 1997) provides evidence that in the span of a year up to 80% of 3,3 -dichloro-benzidine can degrade to benzidine in anaerobic mixtures of sediment/water. Further research to identify the pathways and produets of deeomposition of 3,3 -dichlorobenzidine in various soils is needed. The toxieologieal profile for benzidine eontains information on the environmental fate of that compound (ATSDR 1995). 

Small open-label pilot studies or challenge studies have been reported for the treatment of tics with various agents such as topiramate (Abuzzahab and Brown, 2001), levodopa (Black and Mink, 2000), low-dose naloxone (van Wattum et ah, 2000), donepezil (Hoopes, 1999), cyproterone (Izmir and Dursun, 1999), and ondansetron (Toren et ah, 1999). The safety and effectiveness of the chronic use of these agents, especially in children, requires more systematic studies. 

These caveats noted, there are several areas that deserve special attention, where analyses and social-cultural factors and sources of influence need to be better understood. How are we to understand minority and ethnic differences in decreased medication use, above and beyond their likelihood of use of medications for other conditions While these analyses have not yet been confirmed across a wide range of data sets, such findings are provocative, and may warrant more systematic studies of atttitudes, barriers, and stigma within some minority communities. If such findings are confirmed in other statewide and national medication data bases, more in-depth studies of specific minority populations seem warranted. 

Apparently future work lies in the investigation of some of the interesting effects mentioned above and other metal ions. In addition, more systematic studies in nonaqueous solvents are required, the paucity of data here being obvious from Table II. What little evidence we have indicates that here too, solvent release from the metal ion may play an important role in forming metal complexes. Already, interesting effects of small amounts of water on labilizing coordinated methanol have been observed (77, 112). 

Not surprisingly, the very interesting and practically useful properties of Prussian blue have resulted in several studies of similar hexacyano derivatives [114] but only a few of them (e.g., ruthenium- and osmium-based systems) have found use in electrochromic devices. More systematic studies should, indeed, be called for in order to harvest the full potential of this group of compounds. 

More complicated anisotropies of the potential are, for example, encountered in the association of two linear dipoles. Adiabatic channel potential curves for this case have been calculated and expressed analytically in Ref. 16. More systematic studies, also comparing SACM and trajectory results, were reported in Ref. [36], One may as well consider open-shell effects for example, the association of two open-shell HO radicals in their lowest rotational state was treated in Ref. 37. Figure 12 shows the lowest rovi-bronic adiabatic channel potential curves for this system. The ultimate goal... 

A somewhat more systematic study has been made of collisional deactivation of vibrationally excited ions. Some diatomic and triatomic systems that have been investigated are included in Table II. Vibrational-to-rotational transfer has been demonstrated95 for vibrationally excited H2+ colliding with helium ... 

A new antiproton facility AD (antiproton decelerator) has been completed at CERN and a series of experimental programs are in progress. These include more systematic studies of the structure and formation of pHe+, higher precision laser spectroscopy, microwave spectroscopy [36] and search for type-II antiprotonic helium based on the excited helium [37]. 

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