Cornwell effect

This phenomenon of antiparamagnetic paramagnetic terms clearly needs a name and is called here the Cornwell effect (ideally the Cornwell-Santry effect). Positive contributions to op (which may or may not be positive overall) are expected in heteronuclear diatomics if they have a IT state this excludes, e.g., HF, InF, and TIF. In homonuclear diatomics, the IT -> a excitation is symmetry-forbidden. The possibility has been mentioned for XeF (34), although, from the chemical shift and calculated values of aa, the resultant Op ( F) is negative in XeFg and KrFj (cf. Fig. 7). Another candidate is FC DH, from the evidence of the fluorine chemical shift and spin-rotation interaction (96). According to this interpretation there should be a substantial upheld shift of the... 

Groups V and VI, is higher for the lower fluorides of the halogens or xenon a comparative study of Cornwell effects would be of interest here. 

The most striking feature of Figs. 7 and 8, particularly as compared with the hydride plot, is the plunge downfield of the resultant shielding, following the paramagnetic term, across the row of the central atom for the typical elements, and also for the early transition metals (Fig. 8), with ready circulation of fluorine 2p electrons into empty t g orbitals in the complexes. Fluorine is h hly shielded however in the d molecules and ions, and this was discussed in Section III, B as a possible Cornwell effect (62). 

Cornwell effect, 18 206, 207 correlations with spectroscopic and other properties, 22 230, 231... 

Cornwell, P.A., et al. 1994. Wide-angle x-ray diffraction of human stratum corneum Effects of hydration and terpene enhancer treatment. J Pharm Pharmacol 46 938. 

Wang, P.M., M.G. Cornwell, and M.R. Prausnitz. 2002. Effects of microneedle tip geometry on injection and extraction in the skin. Proceedings of the Second Joint EMBS/BMES Conference, Houston. 

Calder et al., 1991), or have no effect on cell growth (Bailey and Dunbar, 1973 Spector et al., 1981 Cornwell and Morisaki, 1984). 

For a number of years the existence of a porous or polar pathway through the stratum comeum, in parallel with the lipoidal pathway, has been hypothesized. Although there has been some criticism of this concept, it is our belief that the root of the lack of a common consensus among scientists in the field can be attributed largely to the limited number of systematic studies in the literature that directly address the issue of the diffusion of polar and ionic permeants across skin. Based upon recent studies that have focused upon this aspect of transdermal diffusion, the existence of a porous permeation pathway through HEM is clear (Hatanaka et al., 1993, 1994 Peck et al., 1993, 1994, 1995). At this point, we have made no attempt to correlate the findings from our studies with specific structural properties of the HEM. In some cases, authors have implicated shunt routes such as hair follicles and sweat ducts to account for permeation data not consistent with the concept of lipoidal membrane permeation (Cornwell and Barry, 1993 Scheuplein and Blank, 1971). Under ionto-phoretic conditions, such shunt routes have been shown to contribute to current conduction (Cullander and Guy, 1991 Scott et al., 1993). When efforts have been made to estimate the effective Rp of skin samples under iontophoretic conditions (Ruddy and Hadzija, 1992), osmotic conditions (Hatanaka et al.,... 

The response of denitrification to certain environmental factors varies according to how strongly the process is coupled to nitrification. An increase in O2 penetration into sediments can stimulate coupled nitrification-denitrification by enhancing NOj" availability (Rysgaard et al., 1994), but simultaneously depress water column-supported denitrification because of the increased distance that NOj" must diffuse to reach the anaerobic layer (Cornwell et al., 1999). Risgaard-Petersen et al. (1994) reported that a photosynthesis-induced increase in O2 penetration into an estuarine sediment doubled the coupled nitrification-denitrification rate, but reduced the amount of water column-supported denitrification by 50%. Because the contribution of coupled nitrification-denitrification to total denitrification at this site was small (—16%), the net effect of deeper O2 penetration was to reduce... 

Chlorinating drinking water kills microbes but produces trace amounts of a group of potentially harmful substances called trihalomethanes (THMs), the most prevalent of which is chloroform. Federal regulations have been proposed to limit THM levels in drinking water to 40 Xg/L (Davis and Cornwell, 1998). Sparging with ambient air in a bubble column is an effective method to strip the water of THMs. 

If one role of PKG is to decrease smooth muscle intracellular Ca levels, then the mechanism by which this occurs is still not completely defined. Several protein substrates that are known to be phosphorylated by activation of PKG have been identified in SMCs, platelets, and other tissues. Interestingly, some of these proteins have been shown by others to regulate intracellular Ca levels in various cell types. For example, phospholamban, when phosphorylated by PKA in cardiac myocytes, dissociates from sarcoplasmic reticulum (SR) Ca -ATPase resulting in the enhanced sequestration of Ca into the SR (Lindemann et al., 1983). A similar effect of PKG activation has been shown in SMCs (Cornwell et al., 1991 Karczewski et al., 1992 Raeymaekers et al., 1988 Sarcevic et al., 1989). Using another example, Supattopone et al. (1988) reported that PKA-dependent phosphorylation of the inositol 1,4,5-trisphosphate (IP3) receptor in broken-cell fractions decreased Ca release from brain microsomes. Our laboratory has recently shown that the IP3 receptor is also phosphorylated by PKG in vitro on the major PKA phosphorylation site (i.e., Ser-1755) (Komalavilas and Lincoln,... 

Rashatwar, S. S., Cornwell, T. L., and Lincoln, T. M. (1987). Effects of 8-bromo-cGMP on Ca levels in vascular smooth muscle cells Possible regulation of Ca -ATPase by cGMP-dependent protein kinase. Proc. Natl. Acad. Sci. U.S.A. 84, 5685-5689. 

Carbon fibre hazard concerns NASA, Aviation Week Space Technology, 47-50, Mar 5 1979. Cornwell AC, Initial tests on the effect of fire of carbon fibre laminates, RAE Technical Memorandum Mat, 354, 1980. 

Cornwell, D. Lee, R. 1993. Waste stream recycling its effects on water quality. AWWA (American Water Works Association) 86(ll) 50-63. 

Gavino, V.C., Miller, J.S., Ikharebha, S.O., Milo, G.E. and Cornwell, D.G. (1981) Effect of polyunsaturated fatty acids and antioxidants on lipid peroxidation in tissue cultures. J. Lipid Res. 22, 763-769. 

This is the only possibility to determine experimental, or rather semi-experimental, absolute shielding constants, as one can only obtain differences in the shielding constants, i.e. chemical shifts, from NMR spectra as discussed in Section 5.7. However, one has to be careful in applying this relation similar to the relation between the rotational g tensor and the magnetizability, Eq. (6.30). First, one has to take care of the vibrational corrections in the measured spin rotation tensors and secondly NMR spectra are normally measured in the liquid phase so that solvent effects would have to be considered as well. Nevertheless, it has been used to establish absolute shielding scales for several light nuclei (Flygare, 1964 Hindermann and Cornwell, 1968 Jameson et al, 1980 Vaara et al, 1998 Puzzarini et al, 2009). 

A strong benefit of NCS analysis (as in other NAO/NBO decompositions) is the effective reduction to a minimal basis description, comparable to that assumed in qualitative MO theory. This allows many qualitative MO concepts to be usefully applied even when (as usual) the actual GIAO calculations are performed at a far higher theoretical level. For example, Cornwell showed the usefulness of relating inductive... 

Cornwell DW, Rodary G., Modification of rigid PVC properties through effective use of synthetic calcium carbonates of controlled morphology and surface character, Plastic, Rubbers and Composites, 34, 105-110(2005)... 

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