CHF

Figure A3.13.6. Time evolution of the probability density of the CH cliromophore in CHF after 50 fs of irradiation with an excitation wave number = 2832.42 at an intensity 7q = 30 TW cm. The contour...

Figure A3.13.7. Continuation of the time evolution for the CH eln-omophore in CHF after 90 fs of irradiation (see also figure A3,13,6). Distanees between tire eontoiir lines are 10, 29, 16 and 9 x 10 rr in the order of the four images shown. The averaged energy of the wave paeket eorresponds to 9200 em (roughly 6300 em absorbed) with a quantum meehanieal imeertainty of +5700 enC (from [97]).

Figure A3.13.9. Probability density of a microcanonical distribution of the CH cliromophore in CHF within the multiplet with cliromophore quantum nmnber V= 6 (A. g = V+ 1 = 7). Representations in configuration space of stretching and bending (Q coordinates (see text following (equation (A3.13.62)1 and figure A3.13.10). Left-hand side typical member of the microcanonical ensemble of the multiplet with V= 6...

Figure A3.13.10. Time-dependent probability density of the isolated CH clnomophore in CHF. Initially, tlie system is in a Fenni mode with six quanta of stretching and zero of bending motion. The evolution occurs within the multiplet with chromophore quantum number A = 6 = A + 1 = 7). Representations are given...

IVR in tlie example of the CH clnomophore in CHF is thus at the origin of a redistribution process which is, despite its coherent nature, of a statistical character. In CHD, the dynamics after excitation of the stretching manifold reveals a less complete redistribution process in the same time interval [97]. The reason for this is a smaller effective coupling constant between the Fenni modes of CHD (by a factor of four) when... 

This same approach can be extended to find the pH of a monoprotic weak base, replacing with Kb, Chf with the weak base s concentration, and solving for the [OH ] in place of [H3O+]. 

Iodine pentafluoride fluotinates CCl at room temperature to give CCIF and traces of CCI2F2 (91). It reacts with CHI to yield CHF and CHIF2 (92) and with CI to form C2F2 (92) and CIF (93). With CBr at 90°C, IF forms 83% CBr2F2 and minor amounts of CBr F and CBrF. ... 

Most chlorofluorocarbons are hydrolytically stable, CCI2F2 being considerably more stable than either CCl F or CHCI2F. Chlorofluoromethanes and ethanes disproportionate in the presence of aluminum chloride. For example, CCl F and CCI2F2 give CCIF and CCl CHCIF2 disproportionates to CHF and CHCl. The carbon—chlorine bond in most chlorofluorocarbons can be homolyticaHy cleaved under photolytic conditions (185—225 nm) to give chlorine radicals. This photochemical decomposition is the basis of the prediction that chlorofluorocarbons that reach the upper atmosphere deplete the earth s ozone shield. 

A solubihty parameter of 24.5-24.7 MPa / [12.0-12.1 (cal/cm ) ] has been calculated for PVF using room temperature swelling data (69). The polymer lost solvent to evaporation more rapidly than free solvent alone when exposed to air. This was ascribed to reestabUshment of favorable dipole—dipole interactions within the polymer. Infrared spectral shifts for poly(methyl methacrylate) in PVF have been interpreted as evidence of favorable acid—base interactions involving the H from CHF units (70). This is consistent with the greater absorption of pyridine than methyl acetate despite a closer solubihty parameter match with methyl acetate. 

Artificial Hearts. Congestive heart failure (CHF) is a common cause of disabiHty and death. It is estimated that three to four million Americans suffer from this condition. Medical therapy in the form of inotropic agents, diuretics (qv), and vasofilators is commonly used to treat this disorder (see Cardiovascularagents). Cardiac transplantation has become the treatment of choice for medically intractable CHF. Although the results of heart transplantation are impressive, the number of patients who might benefit far exceeds the number of potential donors. Long-term circulatory support systems may become an alternative to transplantation (5). 

Moreover, digitahs has indirect effects on the circulation, which in normal hearts results in a small increase in arterial pressure, peripheral resistance, and cardiac output (114). The effects of digitahs on the circulation of an individual experiencing congestive heart failure are much more dramatic, however. The increased cardiac output, for example, increases renal blood flow which can reheve in part the edema of CHF associated with salt and water retention (114). 

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