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Aluminium‐Abscheidung aus aprotischen Elektrolyten – eine alte Idee in neuem Stil

Aluminium‐deposition from aprotic electrolyte – an old concept with new style Organo‐aluminium complex compounds have been used for many years as elec‐trolyte for the galvanic deposition of aluminium. For the galvanic deposition suitable electrolyte are aprotic complexes of type MX·2 AlR₃ solved in liquid aromatic hydrocarbons. By using aluminium‐magnesium alloy anodes or by using separate aluminium and magnesium anode circuits also AlMg‐alloy layers with high alkali resistance from aprotic electrolyte can be deposited. The aluminium layers have a microcristalline and low‐porous structure. The galvanic aluminization has become an issue of great interest for industrial applications due to its excellent corrosion behaviour and due to the fact that the resistance to hydrogen embrittlement can not be exceeded at deposition from non‐aqueous electrolyte. Therefore the galvanic aluminization from organo‐aluminium electrolyte becomes more and more important being expressed in numerous industrial examples.     

Advances in a-Si:H/c-Si heterojunction solar cell fabrication and characterization

Our progress in amorphous/crystalline silicon (a-Si:H/c-Si) heterojunction solar cell technology and current understanding of fundamental device physics are presented. In a-Si:H/c-Si cells, device performance is strongly dependent on the quality of the a-Si:H/c-Si heterojunction. Four topics are crucial to minimize recombination at the junction and thereby maximize cell efficiency: wet-chemical pre-treatment of the c-Si surface prior to a-Si:H deposition; optimum a-Si:H doping; thermal and plasma post-treatments of the a-Si:H/c-Si structure. By optimizing these aspects using specifically developed characterization methods, we were able to realize (n)a-Si:H/(p)c-Si and (p)a-Si:H/(n)c-Si cells with up to 18.5% and 19.8% efficiency, respectively.     

Single-center randomized trial comparing tacrolimus (FK506) and cyclosporine in the prevention of acute myocardial rejection

BACKGROUND: To compare the efficacy and safety of tacrolimus and cyclosporine in heart transplantation, this single-center, prospective, randomized, open-label clinical trial was undertaken. METHODS: Seventy-three adult patients were randomly assigned at the time of transplantation to receive either tacrolimus (n=43) or cyclosporine (n=30) as the primary immunosuppressant. Ten of the 43 patients in the tacrolimus group received the drug intravenously in the perioperative period; all other patients received only oral tacrolimus. RESULTS: With a mean follow-up of 27 months, patient survival rates (tacrolimus 83%, cyclosporine 81%) were similar. Fewer patients experienced acute rejection in the tacrolimus group (79%) than in the cyclosporine group (100%), but the difference was not statistically significant. The number of infections and dialysis and insulin requirements were similar for the 2 treatment groups, but the proportion of patients requiring multidrug antihypertensive regimens was lower in the tacrolimus group (12.5% vs 50.0% at month 6; p=.025). The interpatient variance in pharmacokinetic parameters in a subset of 10 patients was much higher after the first oral dose of tacrolimus than at steady-state (eg, first-dose time at which maximal concentration is reached (t(max)): 3.5+/-2.5h, steady-state t(max): 2.0+/-0.7h), and patients treated with intravenous tacrolimus (n=13) rather than oral tacrolimus (n=30) reached target concentrations faster and with less interpatient variability (eg, at day 0: 9.72+/-10.9 ng/mL intravenously vs 3.31+/-8.1 orally). CONCLUSIONS: Tacrolimus was associated with similar efficacy and safety profiles compared with cyclosporine. The higher interpatient variance in absorption associated with oral tacrolimus during the first few days after transplantation would suggest that intravenous tacrolimus should be used during the perioperative period.     

Age profile,personnel costs and scientific productivity at the University of Vienna

This study analyzes the age profile of scientific employees and its relation to personnel costs and scientific productivity within eight faculties at the University of Vienna. The age demography can overall be divided into two main categories: Category one faculties represent an increased number of younger aged researchers (Catholic-, Protestant Theology, Law, Economics, Information Sciences, and Medicine), category two faculties show an increased number of older aged researchers (Social Sciences, Humanities, and Science). In addition, it can be demonstrated that the personnel costs for full professors are higher within four faculties (Catholic-, Protestant Theology, Law, and Economics and Information Sciences). Inevitably, this leads to savings for habilitated and non- habilitated researchers at these faculties. The faculty of Medicine represents a well-balanced use of personnel costs. Three faculties (Social Sciences, Humanities, and Sciences) have to pay dramatically more for their older aged habilitated and non-habilitated personnel. For the entire university and two faculties, Medicine and Humanities, a positive and significant relationship between age and the average weekly teaching performance is shown. This study suggests that institutions with a high percentage of older researchers, mainly in the categories of habilitated and non- habilitated personnel, must change their policy to become more flexible and attractive for new talented young people. Due to the fact, that this cannot only be realized through the introduction of new laws, each faculty must establish a scientific plan combined with reorganizations of the personnel structure and personnel costs. This revised version was published online in August 2006 with corrections to the Cover Date.     

A case of conflicts in conservation: Two trenches or a three-dimensional complexity?

Conflicts over conservation are often regarded as dichotomies of diametrical opposites. When national parks are established in Norway, two stereotypes can be sketched: (1) the ecocentric position valuing 'pure, authentic nature', relying on the national government as the only acceptable decision and management level; and (2) a more anthropocentric position valuing cultural landscape elements and certain traditional and future uses of the area, favouring local management. A conflict over restoring a firing range to a state of 'authentic nature' for future designation as a national park is examined. The case has raised comprehensive local debate. It is asked whether the relevant actors should be seen as situated in the stereotypes, or whether a more complex three-dimensional picture would provide a better interpretation.     

The effect of reduced tillage agriculture on carbon dynamics in silt loam soils

Reduced tillage (RT) agriculture is an effective measure to reduce soil loss from soils susceptible to erosion in the short-term and is claimed to increase the soil organic carbon (SOC) stock. The change in distribution and total SOC stock in the 0–60 cm layer, the stratification of microbial biomass carbon (MB-C) content in the 0–40 cm layer and the carbon (C) mineralization in the upper 0–5 cm layer in silt loam soils in Western Europe with different periods of RT agriculture were evaluated. Ten fields at seven locations, representing the important RT types and maintained for a different number of years, and eight fields under conventional tillage (CT) agriculture with similar soil type and crop rotation were selected. RT agriculture resulted in a higher stratification of SOC in the soil profile than CT agriculture. However, the total SOC stock in the 0–60 cm layer was not changed, even after 20 of years RT agriculture. The MB-C was significantly higher in the 0–10 cm layer under RT agriculture, even after only 5 years, compared to CT agriculture. The higher SOC and MB-C content in the upper 0–5 cm layer of RT fields resulted in a higher C mineralization rate in undisturbed soil in the laboratory. Simulating ploughing by disturbing the soil resulted in inconsistent changes (both lower and higher) of C mineralization rates. A crop rotation with root crops, with heavy soil disturbance every 2 or 3 years at harvest, possibly limited the anticipated positive effect of RT agriculture in our research.     

Hydroxylation of the Acetyltransferase NAA10 Trp38 Is Not an Enzyme-Switch in Human Cells

NAA10 is a major N-terminal acetyltransferase (NAT) that catalyzes the cotranslational N-terminal (Nt-) acetylation of 40% of the human proteome. Several reports of lysine acetyltransferase (KAT) activity by NAA10 exist, but others have not been able to find any NAA10-derived KAT activity, the latter of which is supported by structural studies. The KAT activity of NAA10 towards hypoxia-inducible factor 1α (HIF-1α) was recently found to depend on the hydroxylation at Trp38 of NAA10 by factor inhibiting HIF-1α (FIH). In contrast, we could not detect hydroxylation of Trp38 of NAA10 in several human cell lines and found no evidence that NAA10 interacts with or is regulated by FIH. Our data suggest that NAA10 Trp38 hydroxylation is not a switch in human cells and that it alters its catalytic activity from a NAT to a KAT.     

Effect of Solvent Content on the Separation and the Energy Consumption of Extractive Distillation Columns

This article sets out to evaluate the effect of solvent content in the extractive section on the separation efficiency and energy consumption of extractive distillation columns. Contrary to the classical approach, the proposed approach enables a simultaneous evaluation of the effect of the major decision variables (reflux ratio, solvent flow rate, and the number of stages of the extractive section [NSE]). The procedure allows calculating the minimum solvent flow rate for the separation and the minimum specific energy consumption. The results show that the minimum specific energy consumption is obtained for the minimum reflux ratio and not for the minimum solvent flow rate. Moreover, the results show that it is not always the case that a larger NSE results in lower energy consumption. Due to its industrial importance, the dehydration of aqueous mixtures of ethanol using ethylene glycol as solvent has been chosen as a case study.