Mikrobielle Werkstoffzerstörung – Schadensfälle und Gegenmaßnahmen: Umweltrechtliche Belange

Microbial deterioration of materials – case histories and countermeasures: Legal aspects of environmental protection Biofouling is a natural process. Usually, it does not cause too much harm if taken care of properly. If biofouling is fought by special means, problems may arise. The waste water does not meet the due standards. Sometimes the recipe of the treatment agent is not known. If the treatment causes more problems than it can solve help is needed quickly. Yet, it is advisable to keep one's mind clear. Wrong help can become very expensive. In addition, legal punishment will follow, if environmental legislation is hurt. Damages of the environment will be payed by an insurance company only, if the risk is covered by the insurance contract in advance. The best way to be sure is to have a good lawyer, a good expert in environmental techniques and environmental legislation, a good insurance, and to anticipate possible risks.     

Differential effects of aging on directional and absolute errors in visuospatial memory.

Studied memory for visuospatial arrays in 28 male and 34 female healthy dextral adults (aged 20–90 yrs). 10 abstract figures were presented in each hemispace over a series of learning trials, and then delayed free recall of figure placement was obtained. Figures were misplaced significantly downward and leftward in both hemispaces. Both vertical and horizontal absolute error increased significanty with age, but no age effects on directional errors were observed. The increase in absolute error over age is consistent with decreased anterograde memory and visuospatial skills in the elderly. The directional errors are believed to result from an attentional shift toward proximal peripersonal space, in combination with attentional shifts from differential left vs right cerebral activation. Gender effects were also observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Efficient calculation of self/mutual impedances in MoM analysis ofa monopole in free space

This paper presents an analysis of a monopole in free space. The result is given in a concise form that facilitates numerical programming. Moreover, the calculation involves no numerical integration and, thus, the computation is extremely fast     

Generating efficient protocol code from an abstract specification

A protocol compiler takes as input an abstract specification of a protocol and generates an implementation of that protocol. Protocol compilers usually produce inefficient code both in terms of code speed and code size. We show that the combination of two techniques makes it possible to build protocol compilers that generate efficient code. These techniques are: (i) the use of a compiler that generates from the specification a unique tree-shaped automation (rather than multiple independent automata) and (ii) the use of optimization techniques applied at the automation level, i.e., on the branches of the trees. We have developed a protocol compiler that uses both these techniques. The compiler takes as the input a protocol specification written in the synchronous language Esterel. The specification is compiled into a unique automation by the Esterel front end compiler. The automation is then optimized and converted into C code by our protocol optimizer called HIPPCO. HIPPCO improves the code performance and reduces the code size by simultaneously optimizing the performance of the common path and optimizing the size of the uncommon path. We evaluate the gain expected with our approach on a real-life example, namely a working subset of the TCP protocol generated from an Esterel specification. We compare the protocol code generated with our approach to that derived from the standard BSD TCP implementation. The results are very encouraging. HIPPCO-generated code executes up to 25% fewer instructions than the BSD code for input packet processing while only increasing the code size by 25%     

Cyclic GMP inhibits and shifts the activation curve of the delayed-rectifier (I[K1]) of type I mammalian vestibular hair cells

NITRIC oxide (NO) plays a role in the modulation of the predominant potassium current of type I vestibular hair cells, a low-voltage activated current called I(K1). Since many effects of NO are mediated via cGMP, patch-clamp recordings were made to evaluate the effects of cGMP on I(K1). In whole-cell recordings 1 mM cGMP shifted Vhalf of I(K1) by 15.0 +/- 2.4 mV (n = 6) to more positive. In cell-attached 'multichannel' recordings 1 mM 8-bromo-cGMP caused a reversible shift of Vhalf by 13.8 +/- 2.6 mV (n = 12) and in single channel recordings in the cell-attached configuration the open probability was reduced at -60 mV from 0.39 +/- 0.14 to 0.08 +/- 0.01. cGMP had no effect on excised inside-out patches, indicating that an intact cytosolic milieu with functioning phosphorylation cascades is necessary. cGMP seems to be an important second messenger which reduces the potassium conductance of vestibular hair cells.     

Low density lipoprotein catabolism is enhanced by the cleaved form of alpha-1-antitrypsin

The frequent occurrence of hypocholesterolaemia following inflammatory processes is well known but unexplained. Elevated plasma levels of serine proteinase inhibitors (serpins) and their complexes with target enzymes have been demonstrated in inflammatory, malignant and infectious diseases which are also often accompanied by low plasma cholesterol levels. Under inflammatory conditions, uncomplexed, but cleaved inactive serpins arising from slow deacylation of the serpin-proteinase complex may be present in the circulation. To determine the influence of native and cleaved forms of serpins, such as alpha-1-antitrypsin (AAT), on lipoprotein metabolism, we investigated the effect of these forms on low density lipoprotein (LDL) catabolism in human HepG2 cell line. We have found that the cleaved form of AAT in concentrations from 125 to 2000 nmol l-1 stimulates LDL binding to the HepG2 cells, by up to 49% with a subsequent increase in LDL uptake and degradation of up to 79 and 65% respectively. Native AAT was also found to increase LDL binding and internalization by 20-25%, independently of the amount of AAT added, an effect most probably due to the cleaved form of AAT produced by local proteolysis of native AAT incubated in the cell culture. Moreover we have shown that the cleaved form of AAT interacts with LDL in vitro, and that such an interaction abolishes AAT ability to stimulate LDL binding and internalization. This study for the first time describes the ability of the cleaved form of AAT to stimulate LDL binding and internalization in HepG2 cell culture, and provides evidence that hypocholesterolaemia occurring during inflammatory processes may be mediated by cleaved forms of serpins.     

The dependence of stress induced voiding on line width studied by conventional and high resolution resistance measurements

The degradation due to stress induced voiding of nitride passivated Al-1 wt.% Si and Ti/TN/ Al-1wt.% Si-0.5 wt. % Cu/Ti/TN interconnects with widths ranging between 0.4 and 1.2 μm was studied by in-situ conventional high resolution resistance measurements (HRRM) during storage at temperatures between 168 and 240°C. The conventional measurements on Al-Si lines, which lasted more than one year, clearly showed that the interconnect lifetime decreases with decreasing line width. With HRRM the degradation due to stress induced voiding can be detected much sooner and with much more detail. From the HRRM it is clear that the resistance changes during storage often happen in jumps and that the degradation has a rather complex alloy, line width and temperature dependence. Both for 0.4 and 0.6 μm wide Al---Si lines more degradation occurred for storage at 175 °C compared to storage at 200 °C. For the Al---Si---Cu stacks the degradation of 0.4 μm wide lines was worse for storage at 240°C compared to storage at 200 °C, but the opposite was true for the 0.6 μm wide lines.     

A multiplicative damage model for strength of fibrous compositematerials

Knowledge of the tensile strength properties of a fibrous composite material is essential in the design of reliable structures from that material. Determination of statistical models for the tensile strength of a composite material which provide good fits to experimental data from tensile tests on material specimens is therefore important for engineering design. Perhaps the most commonly used statistical model is the Weibull distribution, based on `weakest link of a chain' arguments. However, in many cases the usual Weibull distribution does not adequately fit experimental data on tensile strength for composite materials made from brittle fibers such as carbon. Here, an alternative model is developed for tensile strength of carbon composites, which is based on a multiplicative cumulative-damage approach. This approach results in a 3-parameter extension of the Birnbaum-Saunders fatigue model and incorporates the material specimen size (size effect) as a known variable. This new distribution can also be written as an inverse Gaussian-type distribution, which can be interpreted as the first passage of the accumulated damage past a damage threshold, resulting in material failure. The new model fits experimental tensile-strength data, for carbon micro-composites better than existing models, providing more accurate estimates of material strength     

Influence of the intensity of gg irradiation on the photoluminescence of GaAs:Te

The influence of gg irradiation (⁶⁰Co) of various intensities (P _γ≈1.7−7.5kGR/h) on the photoluminescence of GaAs:Te single crystals [n ₀=(1.2–2.3×10¹⁸ cm⁻³] is investigated. Together with the known photoluminescence impurity bands (hν _max≈1.2 eV and/or hν _max≈1.35 eV) and edge band (hν _max≈1.51 eV), new bands are also observed in the spectra at hν _max≈1.3 eV and hν _max≈1.48 eV. The observed effects are attributed to radiation-stimulated ordering of the donor impurity and deep impurity centers. Fiz. Tekh. Poluprovodn. 32, 38–39 (January 1998)