Photokinetics


Book Description

Many books cover the determination of rate constants under different experimental conditions and different chemical composition of the reaction mixture in their formal treatment of thermal kinetics. However, most textbooks are limited to simple mechanisms. In contrast, analogous treatment of photochemical reactions is limited to the publication of special reactions and investigations. Therefore, this book is aimed at providing an overall description of formal photokinetics covering a wider scope than the usual books on kinetics.This volume attempts to provide a concise treatment of both thermo- and photochemical reactions by means of generalised differential equations, their set-up in matrix notation, and their solution by a formalism using numerical integration. At a first glance this approach might be surprising. However, apart from the argument that the didactics of thermal reactions are easier to handle than those of kinetics, the book provides additional reasons in support of this approach. Therefore, the formalism derived allows the evaluation of photochemical reactions, which are superimposed thermal reactions taking into account that the amount of light absorbed varies during the reaction. Because of this, any approximation, either by using total absorbance or negligible absorbance, will cause considerable errors even for simple reactions. The approach chosen to transform the axis of the radiation time into a new variable that includes the photokinetic factor proves that formal kinetics can be applied to thermal and photochemical reactions as well, and even allows the handling of solutions that cannot be homogenised or solid samples in which the concentration varies locally. By using this approach to introduce partial photochemical quantum yields even complex mechanisms can be determined quantitatively.A large number of examples for different mechanisms and an introduction to many spectroscopic and chromatographic methods suitable for photokinetic analyses are provided to enable the reader to carry out a step-by-step evaluation of his own measurements. To reduce the number of formula in some chapters an appendix has been included which contains a detailed description of the calculus of some essential examples. For the convenience of the reader the following has been included:• A large number of examples describing the use of formula• A detailed description of the procedure for applying photokinetics to complex consecutive photoreactions• An Internet address where the reader can find a tutorial for this procedure:http://www.barolo.ipc.uni-tuebingen.de/tele/photokin/• A simple macro to help in programming his own evaluation procedure.




Primary Photo-Processes in Biology and Medicine


Book Description

Recently there have been major developments in the experimental techniques available for the study of the primary events following the absorption of ultra-violet and visible radiation by biological systems. These techniques, which include absorption, emission, resonance Raman, electron spin resonance, nuclear magnetic resonance and photoacoustic spectroscopies, can be used to study the fate of transient species with lifetimes ranging from seconds to nanoseconds and extending in some cases, such as laser flash photolysis, to pico 12 15 (10- S)- and even femtoseconds (10- s). In parallel with these developments there has been a dramatic increase in the use of light in medicine via the direct photochemical alteration of endogenous molecules (phototherapy) or via the photoactivation of drugs in the skin or other tissue (photochemotherapy). Thus neonatal hyperbili rubinaemia can be routinely treated by phototherapy and psoriasis is frequently treated by PUVA photochemotherapy. A promising new photo chemotherapy used the phototoxicity of porphyrin drugs activated by red light to destroy solid malignant tumors. While some of the overall qualitative effects of such treatments are known, only recently have we begun to understand the associated molecular mechanisms. The primary molecular processes involve short-lived species. The pur pose of this Advanced Study Institute was to review some newer experi mental techniques for the study of such species, the application of these techniques to biological and medical systems and to examine the value of such information in phototherapeutic situations.










Gould's Medical Dictionary


Book Description







Pharmaceutical Photostability and Stabilization Technology


Book Description

Based on a training course developed by Dr. Joseph T. Piechocki and other experts in this field whose contributions appear in this book for two International Meetings on the Photostability of Drugs and Drug Products, this text clarifies the guidelines set by the International Conference on Harmonization (ICH) and provides a comprehensive background










Taschenwörterbuch der Biochemie / Pocket Dictionary of Biochemistry


Book Description

Birkhäuser's Pocket Dictionary of Biochemistry is the most comprehensive English-German/German-English dictionary on the international market. More than 30.000 entries and subentries with some 50.000 translations and an extent appendix with a specifically compiled list of abbreviations provide users with an unrivaled coverage of biochemistry and related bioscientific areas. The dictionary excels through a harmonious synthesis of biochemical and general bilingual dictionaries, making it the ideal choice for users from both scientific and linguistic fields. Furthermore Birkhäuser's Pocket Dictionary of Biochemistry is marked by a first class linguistic and lexicographic treatment achieving a very high user friendliness and user satisfaction. In the English-German part British terms have been included in addition to American terms, thus making it possible to find entries from either language.