Bücherbesprechungen

Ohne Zusammenfassung     

Dilatometrische Untersuchung der Hitzedenaturierung von Eiweißlösungen

Zusammenfassung Bei dilatometrischer Verfolgung der Hitzekoagulation w?sseriger Eiwei?l?sungen findet man nur sehr geringe Volumschwankungen im Ausma? von 0,01 bis 0,07 ccm auf je 100 g des trockenen Proteins. Daraus wird geschlossen, da? dieDenaturierung weder mit einer?nderung der Hydratation noch auch mit einer?nderung des Gehaltes an freien sauren und basischen Gruppen und der Gesamtladung einhergeht. Sie beruht vermutlich auf einer prim?ren Sprengung der innermolekularen Anziehung zwischen positiven und negativen Atomgruppen und einer damit verbundenenAufrichtung der im nativen Eiwei? gekrümmten und gespannten Peptidketten. Durch die damit verbundene Lockerung des Eiwei?moleküls wird diegegenseitige Polarisation der Eiwei\moleküle erleichtert. Sieführt zur Verknüpfung der Eiwei?moleküle, zur Bildung gro?er Molekülaggregate und damit zurFlockung.     

Photon upconversion based on sensitized triplet–triplet annihilation

Photon upconversion, the process wherein light of long wavelength is frequency converted to photons of higher energy, is readily achieved at low incident power through sensitized triplet–triplet annihilation (TTA) in various chromophore combinations spanning the UV to the near-IR. This emerging wavelength-shifting technology truly represents a viable route towards converting low energy terrestrial solar photons into light adequate to drive electron transfer in operational photovoltaics. Generalized molecular design constraints, all operational examples reported to date, and measurement techniques applied to these low power nonlinear processes are reviewed in this contribution. In many instances, direct visualization of this phenomenon is presented in solution and within various polymeric host materials.     

Influence on elemental status by hip-endoprostheses

For many clinical purposes various artificial devices are applied, which contact human tissue and can thus cause adverse reactions between prosthetic surfaces and body components. Of the many materials applied for orthopaedic joint replacements the most common are cobalt-chromium-molybdenum alloys. In these cases considerable amounts of cobalt-chromium-molybdenum wear particles are released from the prostheses which have to be regarded as a cause of long-time problems for the patient.Since these particles are dissolved in body fluids of the surrounding area they are distributed in the whole body via blood. Elevated metal concentrations have been found in blood and urine of persons with endoprostheses. Partly the metals are excreted via urine, but to some extend they accumulate in different organs.Therefore this study dealt with the development of an analytical method for the determination of seven relevant trace elements, namely Al, Co, Cr, Mo, Nb, Ni, and Ti in nine kinds of human tissue (brain, heart, kidney, liver, lung, muscle, lymphatic nodes, spleen, body fat) starting with drawing of the sample, sample work up and finally analysis by means of atomic spectrometry. The optimized method was then applied to determine the metal contents in organs of persons (post mortem) with total hip replacements with metal on metal bearing surfaces. Comparison of the data obtained with those of persons without hip-endoprostheses shows that brain and lung are the main targets for elemental accumulation in persons with hip-endoprostheses. Mo and Nb represent the elements with the highest tendency to be accumulated.     

Ueber Körper,welche von confocalen Flächen zweiten Grades begränzt sind

Ohne Zusammenfassung