[en] Comparative studies of the photophysical and photochemical properties and of the photosensitizing efficiency of pheophorbide a and hematoporphyrinderivative (HPD) on biomolecules, human neutrophils, and tumor cells were carried out in vitro and in vivo. It was found that the photodynamic efficacy of pheophorbide a on cells in vitro and in vivo is comparable with that of HPD. The results of our investigations demonstrate the possibility that pheophorbide a or one of its derivatives may become a hopeful drug for photodynamic therapy competitive to HPD. (author)

[en] The photosensitizing efficacy and the mechanisms of photodynamic action of pheophorbide a and hematoporphyrinderivative (HPD) on tryptophan and human serum albumin (HSA) were studied. It was shown that for both drugs similar photosensitizing mechanisms took place. They underwent a dark reaction with HSA. For pheophorbide a the binding efficiency to albumin is smaller than for HPD derivative, and the monomerization of pheophorbide a is less effective. The photosensitizing efficiency of pheophorbide a on tryptophan and HSA is smaller than of HPD, whereas the photodynamic action on cells is nearly the same. These different results may be explained in terms of aggregation and hydrophobicity of the porphyrins. (author)

[en] Two novel monofullerene-bis(pyropheophorbide a) complexes were synthesized and their photophysical properties were studied by using both steady-state and time-resolved techniques. It was revealed that in the pyropheophorbide a (pyroPheo)-C₆₀ molecular system (FP1) strong quenching of the first excited singlet state of the pyroPheo and, as result, dramatically decreasing of photosensitized singlet oxygen generation occurs by efficient photoinduced electron transfer to the fullerene molecule with a rate constant of 2.5 x 10⁹ s^-1. In contrast, the fullerene hexaadduct-bis(pyroPheo) system (FHP1), which possesses five diethyl malonate addends in the remaining octahedral positions, shows a high singlet oxygen quantum yield which is due to the reduced fullerene chromophore which is not a good electron acceptor anymore

[en] Doppler-tuned laser spectroscopy has been applied to a foil-stripped 1 MeV/u silicon ion beam to measure the 1s2s ¹S₀-1s2p ³P₁ intercombination interval in ²⁸Si¹²⁺. To obtain sufficient transition probability the Si¹²⁺ beam was merged co-linearly with over 2 kW of continuous-wave laser light at 1319 nm inside an ultra-high finesse build-up cavity. The measurement differentiates between current theories for the n=2 levels of helium-like ions.

[en] The uptake of ¹⁴C-(U)-nourseothricin by stationary phase mycelium of Streptomyces noursei JA 3890b-NG 13/14 was demonstrated. An energy-dependent transport system appears to be involved in the transport of the antibiotic. Relatively large quantities of the antibiotic were adsorbed to the surface of mycelium. Degradation of nourseothricin by the producing microorganism was not detectable. (author)

No abstract available

[en] Systematic in vitro studies on singlet oxygen luminescence kinetics have been carried out reconciling recently published contradictory results reported for sub-cellular singlet oxygen kinetics obtained with two different approaches: single cell - and cell ensemble measurements. The singlet oxygen luminescence kinetics in two cell lines were investigated after incubation with three different photosensitizers. In each case a strong dependency of the singlet oxygen luminescence kinetics from the applied illumination already at very low doses was observed. Analysis of the obtained results allows judging the usability of the two approaches for detailed investigation of sub-cellular singlet oxygen kinetics. Intrinsically existing detection limits as well as local heating during the measurement will be discussed

[en] UV-irradiated 8-methoxypsoralen (8-MOP) binds to cell membranes. The effect of PUVA therapy on cell membranes, especially on the glycocalyx of isolated lymphocytes was studied by chemical analysis. After 8-MOP and UV treatment the glycocalyx was altered and particles of the cell surface passed into the surrounding medium. Incubation with 5 . 10^-₅ M 8-MOP produced a darkness effect and UV irradiation alone caused also changes of the glycocalyx. In vitro PUVA treatment had no effect on the number of total E-rosette forming lymphocytes, but the number of active E-rosettes increased after incubation with 5 . 10^-₅ M 8-MOP and UVA doses up to 0.4 J/cm₂. UVA doses up to 1.5 J/cm₂ decreased the active E-rosettes. Besides this oxygen-dependent effect, oxygen-independent processes were registered following combined treatment of the glycocalyx

[en] ¹⁴C(n,γ)¹⁵C is being used as a test case in the development of an indirect method to determine neutron capture cross sections on neutron-rich unstable nuclei at astrophysical energies. Our approach makes use of two reactions: one peripheral used to find the asymptotic normalization coefficient (ANC) and a second non-peripheral reaction to determine the spectroscopic factor. The ANC for ¹⁵C has been determined using a HI neutron transfer reaction with a 12 MeV/nucleon ¹⁴C beam on a ¹³C target. The spectroscopic factor will be determined using ¹⁴C(d,p) in forward kinematics with an incident deuteron energy of 60 MeV. Both experiments were performed using the MDM high-resolution spectrometer at Texas A and M University.

[en] In the astrophysically important reaction ¹⁹Ne(p,γ)²⁰Na, the rate is dominated by a single key resonance at 450 keV above the proton-emission threshold in ²⁰Na. Throughout the last few decades many experiments have been performed aimed at finding the identity of this state. Despite this, the spin-parity of the key resonant state is still up for debate. The present paper describes a new experiment studying the β-delayed proton decay of ²⁰Mg aimed at solving this issue.