The progressive nature of Wallerian degeneration in wild-type and slow Wallerian degeneration (Wld<Superscript>S</Superscript>) nerves

Background  

The progressive nature of Wallerian degeneration has long been controversial. Conflicting reports that distal stumps of injured axons degenerate anterogradely, retrogradely, or simultaneously are based on statistical observations at discontinuous locations within the nerve, without observing any single axon at two distant points. As axon degeneration is asynchronous, there are clear advantages to longitudinal studies of individual degenerating axons. We recently validated the study of Wallerian degeneration using yellow fluorescent protein (YFP) in a small, representative population of axons, which greatly improves longitudinal imaging. Here, we apply this method to study the progressive nature of Wallerian degeneration in both wild-type and slow Wallerian degeneration (Wld^S) mutant mice.     

Polarisationseffekte des Fluoreszenzlichtes von Plastikszintillator,KJ (Tl), CsJ (Tl) und Anthrazen

Investigating the optical isotropic scintillators KJ (Tl), CsJ (Tl) and plastic NE 102 A a non-vanishing degree of polarization of the emitted light was found. Since the arrangement is otherwise symmetrical, this polarization is only due to the mechanism of activation by deuterons of 27.5 MeV energy. Measurements of fluorescence light emitted by anthracene crystals at room temperature showed within the apparative uncertainty no dependence of polarization from the direction of activation. However such a dependence was found at the temperature of liquid air.     

Improvement of passive Q-switching performance reached with a new Nd-doped mixed vanadate crystal Nd:Gd0.64Y0.36VO4

Passive Q-switching performance was found to be greatly improved by use of a new Nd-doped mixed vanadate crystal Nd:Gd0.64Y0.36VO4 compared with that achieved with Nd:YVO4 and Nd:GdVO4. At an absorbed pump power of 12 W, an average output power of 2.78 W was obtained at a pulse repetition frequency of 15.4 kHz with an optical conversion efficiency of 23.2%, and the slope efficiency was determined to be 45.5%. The resulting pulse energy, peak power, and pulse width were 181 microJ, 26.6 kW, and 6.8 ns, respectively.