Liquid-metal-ion source development for space propulsion at ARC.

The Austrian Research Centers have a long history of developing indium Liquid-Metal-Ion Source (LMIS) for space applications including spacecraft charging compensators, SIMS and propulsion. Specifically the application as a thruster requires long-term operation as well as high-current operation which is very challenging. Recently, we demonstrated the operation of a cluster of single LMIS at an average current of 100muA each for more than 4800h and developed models for tip erosion and droplet deposition suggesting that such a LMIS can operate up to 20,000h or more. In order to drastically increase the current, a porous multi-tip source that allows operation up to several mA was developed. Our paper will highlight the problem areas and challenges from our LMIS development focusing on space propulsion applications.

[Purification, glucose-6-phosphate dehydrogenase inhibition, and HPLC analysis of four 1,8-dihydroxyanthrones]. / Reindarstellung, Glucose-6-phosphat-Dehydrogenase-Hemmung und HPLC-Analytik von vier 1,8-Dihydroxyanthronen.

With regard to the examination of their antipsoriatic properties, four 1,8-dihydroxyanthrones were prepared in a purity greater than 99%: Dithranol (1, anthralin) by chromatographic purification, chrysarobin (2) either by work-up from commercial chrysarobin or by an oxidative cleavage (FeCl3) of aloin, followed by a reduction (SnCl2/HCl) of the produced anthraquinone derivative (6), aloe emodin anthrone (3) by the action of aquous sodium tetraborate on aloin and frangula emodin anthrone (4) by the SnCl2/HCl-reduction of frangula emodin (7) isolated from the dry extract of the bark of alder buckthorn. UV/VIS, IR, 1H-NMR and mass spectra confirmed the structures of the four anthrones which all distinctly inhibited G-6-P dehydrogenase (0.05 mmol, desactivation in 6 h). For clinical studies the anthrones were incorporated into white petrolatum with exclusion of oxygen (under Ar). The anthrone content of the preparations was determined by HPLC (LiChrosorb RP-18, 7 microns [280 x 4 mm]; 1.5 ml/min MeOH/water/HOAc [80:20:0.2]) after extraction with CH2Cl2 (tR = 1: 10.4 min, 2: 15.3 min, 3: 4.7 min, 4: 7.7 min).

Dithranol: further investigations on the structure-activity-relationship. The new series of the 10-mono-alkyldithranol derivatives.

The in vitro stability of 10-ethyldithranol (1,8-dihydroxy-10-ethyl-9(10H)-anthracenone) and its effects on healthy and psoriatic skin is investigated. 10-Ethyl-dithranol as a representative of the new class of 10-alkyldithranol derivatives neither stains nor irritates and has no antipsoriatic activity at all. This is due to the relatively stable substituent at carbon 10 which enables the fast oxidation processes necessary for the antipsoriatic effect. Therefore, antipsoriatically active dithranol derivatives require a free or easily liberated 10-position and hence the so-called 'minimum structure of antipsoriatic anthrones' keeps its validity.

An analysis of T lymphocyte subpopulations in patients with Alzheimer's disease.

The relative proportions of regulatory T lymphocyte subpopulations and T lymphocyte proliferative responses to the mitogen phytohemagglutinin (PHA) were studied in 30 patients with clinically apparent Alzheimer's disease (mean age = 71.5). Comparisons were made with 30 age-matched, nondemented healthy controls (mean age = 68.8) and with 20 younger, normal adult controls (mean age = 27.5). The relative percentages of total peripheral T lymphocytes, T helper/inducer lymphocytes (Th), and T suppressor/cytotoxic lymphocytes (Ts) were similar between the Alzheimer patient group and the age-matched controls. However, when the two older groups were compared with the young adult controls, a significant decrease was seen in the percentage of Ts cells, with a concomitant increase in the ratio of Th:Ts. Lymphocyte proliferative responses to PHA were similar in the Alzheimer patients and their age-matched controls; however, when compared with the young adult controls, a significant decrease in responsiveness for both older groups was observed. These results confirm decreases in certain immune indices with aging, but suggest that there are no changes in T lymphocyte subsets or in lymphocyte proliferation, which are unique to Alzheimer's disease.

[Differential diagnosis between pulmonary embolism and myocardial infarction (author's transl)]. / Zur Differentialdiagnose Lungenembolie/Myokardinfarkt.

The clinical diagnosis and the dissection-diagnosis agree in pulmonary embolism only in 16% of cases and in myocardial infarction in 45-69% of cases, dependent on the localisation of the infarction. ECG signs as a single alteration are to be seen in a relatively low percentage and are therefore of limited value. Clinical and paraclinical symptoms also give only a certain hint.