HOckel

Large annulenes tend to undergo conformational distortion, cis-trans isomerizations, and sig-matropic rearrangements (p. 40 and p. 100). Methylene-bridged conjugated (4n + 2)-ic cyclopolyenes were synthesized with the expectation that these almost planar annulenes should represent stable HOckel arenes (E, Vogel, 1970, 1975). 

BIRCH hOCKEL - BENKESER Reduction Reduction ol aromatics, unsaturated ketones coniugated dienes by alkali metals in liquid ammonia or amines... 

CHEMICAL THERMODYNAMICS DEBYE-HOCKEL MODEL GIBBS FREE ENERGY... 

COULOMB COULOMB S LAW DEBYE-HOCKEL TREATMENT COULOMETRIC TITRATION 4-COUMAROYL-CoA SYNTHETASE COUNTERION Counting efficiency,... 

DAVIES EQUATION DEBYE-HOCKEL TREATMENT Day-night cycle,... 

BIOMINERALIZATION DEBYE-HOCKEL TREATMENT DEFINITE INTEGRAL Degenerate rearrangement,... 

HORN-BORNIG PLOT HORSERADISH PEROXIDASE HOST-GUEST INTERACTIONS HOST MOLECULE CROWN ETHERS MACROCYCLES INCLUSION COMPLEXES HOCKEL MOLECULAR-ORBITAL CALCULATIONS... 

Debye-HOckel screening parameter, Eq. (43) common logarithm of the retention factor... 

At higher ionic strength the limiting Debye-HOckel treatment no longer adequately describes the effect of the ionic atmosphere on the activity of an ion, and this deficiency has been the subject of much theoretical investigation. 

Two semiempirical approaches which to date seem to account best for the effects observed at high ionic istrength, will be discussed here. The first, due to Lietzke et at. 197), views the solution as a mixture of two components one has the limiting Debye-HOckel character apd the other component exhibits the behavior of fused salts. The activity coefficient for fused salts is given by... 

Hockel M, Vaupel P. Tumor hypoxia definitions and current clinical, biologic, and molecular aspects. J Natl Cancer Inst 2001 Feb 21 93(4) 266-276. 

Vaupel P, Kelleher DK, Hockel M. Oxygen status of malignant tumors pathogenesis of hypoxia and significance for tumor therapy. Semin Oncol 2001 28(2 Suppl 8) 29-35. 

HOckel, W. Theoretische Grundlagen der organischea Chemie. 4. Aufl.,... 

M. Hockel, K. Schlenger, C. Knoop, P. Vaupel, Oxygenation of carcinomas of the uterine cervix Evaluation by computerized O2 tension measurements. Cancer Res. 51(22) (1991)6098-6102. 

M. Hockel, K. Schlenger, B. Aral, M. Mitze, U. Schaffer, P. Vaupel, Hypoxia and radiation response in human tumors. Semi. Radiat. Oncol. 6 (1996) 3-9. 

By measuring the solubility, r, of the silver chloride in different concentration of added salt and extrapolating the solubilities to zero salt concentration, or better, to zero ionic strength, one obtains the solubility when v = 1. and from Eq. (29) K can be found. Then y can be calculated using this value of K and any measured solubility. Actually, this method is only applicable to sparingly soluble salts. Activity coefficients of ions and of electrolytes can be calculated from the Debye-HOckel equations. For a uni-univalent electrolyte, in water at 25 C, the equation for the activity coefficient of an electrolyte is... 

DEBYE-HOCKEL LIMITING LAW. The departure from ideal behavior in a given solvent is governed by the ionic strength of the medium and the valences of the ions of the electrolyte, but is independent of their chemical nature. For dilute solutions, the logarithm of the mean activity is proportional to the product of the cation valence, anion valence, and square root of ionic strength giving the equation... 

Most solid tumors develop regions of low oxygen tension because of an imbalance in oxygen supply and consumption. Clinical and experimental evidence suggests that tumor hypoxia is associated with a more aggressive phenotype (Hockel and Vaupel 2001 Vaupel 2008). Hypoxic tumor cells are resistant to conventional chemotherapy and radiotherapy. It is therefore rational to target the hypoxic regions of tumors or disrupt events initiated by hypoxia (Melillo 2004). 

Hypoxia creates conditions that, on one hand, are conducive to the accumulation of extracellular adenosine and, on the other hand, stabilize hypoxia-inducible factors, such as HIF-1 a (Linden 2001 Sitkovsky et al. 2004 Fredholm 2003 Hockel and Vaupel 2001 Minchenko et al. 2002 Semenza 2000). HIF-1, the most important factor involved in the cellular response to hypoxia, has been extensively studied this last decade. However, despite the substantial number of investigations into HIF-1, many secrets about its function remain to be revealed. 

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