Two impossibility theorems on behaviour specification of abstract data types

Two kinds of finite specification of the behaviour of a counter data type are proved impossible.We consider the class of data types (many-sorted algebras) behaving like an encapsulated counter that can be observed only by a test for zero. It is shown that no nonempty subclass of this class can be finitely specified in observational first-order logic, which is a variant of first-order logic in which equality may not be used on encapsulated types. Secondly, it is shown that the class cannot be described exactly by a finite specification in first-order logic.An extended abstract of a part of this paper appeared as: Schoett, O.: An observational subset of first-order logic cannot speacify the behaviour of a counter, in: Choffrut, C., Jantzen, M. (eds) STACS 91. 8th Annual Symposium on Theoretical Aspects of Computer Science (Lect. Notes comput. Sci., vol. 480, pp. 499–510) Berlin Heidelberg New York: Springer 1991     

Fiber optic sensing for ultrasonic NDE

An innovative approach to nondestructive evaluation (NDE) using noncontacting optical sensors has demonstrated. In this effort a single mode optical fiber interferometer (OFI) was used to sense the presence and form of Rayleigh waves traveling along the surface of a steel test bar at a velocity of nearly 3mm/µs. Acousto-optic time-domain data was successfully used to detect the presence and locate the position of a test flaw (a machined slot) in the bar, and spectrum analysis was used to estimate its geometry and size. This approach has many potential applications in the ultrasonic evaluation of real flaws in structures with complex geometries. Coupled with the authors' earlier work demonstrating the feasibility of generating acoustic waves in metals using laser light pulses transmitted through the fiber optic probes, this latest achievement points to the development of a fully noncontacting, fiber optic based thermal-acousto-photonic (TAP) NDE system, with potential applications to the reliability testing of many important structures where composition, scale, geometry, or restricted access preclude the use of conventional NDE techniques.     

Polycyclic Aromatic Hydrocarbons Activate the Aryl Hydrocarbon Receptor and the Constitutive Androstane Receptor to Regulate Xenobiotic Metabolism in Human Liver Cells

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants produced by incomplete combustion of organic matter. They induce their own metabolism by upregulating xenobiotic-metabolizing enzymes such as cytochrome P450 monooxygenase 1A1 (CYP1A1) by activating the aryl hydrocarbon receptor (AHR). However, previous studies showed that individual PAHs may also interact with the constitutive androstane receptor (CAR). Here, we studied ten PAHs, different in carcinogenicity classification, for their potential to activate AHR- and CAR-dependent luciferase reporter genes in human liver cells. The majority of investigated PAHs activated AHR, while non-carcinogenic PAHs tended to activate CAR. We further characterized gene expression, protein abundancies and activities of the AHR targets CYP1A1 and 1A2, and the CAR target CYP2B6 in human HepaRG hepatoma cells. Enzyme induction patterns strongly resembled the profiles obtained at the receptor level, with AHR-activating PAHs inducing CYP1A1/1A2 and CAR-activating PAHs inducing CYP2B6. In summary, this study provides evidence that beside well-known activation of AHR, some PAHs also activate CAR, followed by subsequent expression of respective target genes. Furthermore, we found that an increased PAH ring number is associated with AHR activation as well as the induction of DNA double-strand breaks, whereas smaller PAHs activated CAR but showed no DNA-damaging potential.     

Mushroom-Derived Medicine? Preclinical Studies Suggest Potential Benefits of Ergothioneine for Cardiometabolic Health

Medicinal use of mushrooms has been documented since ancient times, and in the modern world, mushrooms have a longstanding history of use in Eastern medicine. Recent interest in plant-based diets in Westernized countries has brought increasing attention to the use of mushrooms and mushroom-derived compounds in the prevention and treatment of chronic diseases. Edible mushrooms are the most abundant food sources of the modified amino acid, ergothioneine. This compound has been shown to accumulate in almost all cells and tissues, but preferentially in those exposed to oxidative stress and injury. The demonstrated cytoprotectant effect of ergothioneine has led many to suggest a potential therapeutic role for this compound in chronic conditions that involve ongoing oxidative stress and inflammation, including cardiovascular and metabolic diseases. However, the in vivo effects of ergothioneine and its underlying therapeutic mechanisms in the whole organism are not as clear. Moreover, there are no well-defined, clinical prevention and intervention trials of ergothioneine in chronic disease. This review highlights the cellular and molecular mechanisms of action of ergothioneine and its potential as a Traditional, Complementary and Alternative Medicine for the promotion of cardiometabolic health and the management of the most common manifestations of cardiometabolic disease.     

X-ray Fluorescence Uptake Measurement of Functionalized Gold Nanoparticles in Tumor Cell Microsamples

Quantitative cellular in vitro nanoparticle uptake measurements are possible with a large number of different techniques, however, all have their respective restrictions. Here, we demonstrate the application of synchrotron-based X-ray fluorescence imaging (XFI) on prostate tumor cells, which have internalized differently functionalized gold nanoparticles. Total nanoparticle uptake on the order of a few hundred picograms could be conveniently observed with microsamples consisting of only a few hundreds of cells. A comparison with mass spectroscopy quantification is provided, experimental results are both supported and sensitivity limits of this XFI approach extrapolated by Monte-Carlo simulations, yielding a minimum detectable nanoparticle mass of just 5 pg. This study demonstrates the high sensitivity level of XFI, allowing non-destructive uptake measurements with very small microsamples within just seconds of irradiation time.     

Advances in Modeling and Simulation of Grinding Processes

In the last decade the relevance of modeling and simulation of grinding processes has significantly risen which is caused by industrial needs and is indicated by the number of publications and research activities in this area. This keynote paper results from a collaborative work within the STC G and gives an overview of the current state of the art in modeling and simulation of grinding processes: Physical process models (analytical and numerical models) and empirical process models (regression analysis, artificial neural net models) as well as heuristic process models (rule based models) are taken into account, and outlined with respect to their achievements in this paper. The models are characterized by the process parameters such as grinding force, grinding temperature, etc. as well as work results including surface topography and surface integrity. Furthermore, the capabilities and the limitations of the presented model types and simulation approaches will be exemplified.     

Suppression of the development of pores during laser-induced surface dispersion of TiC into aluminium, by means of a static magnetic field

A static magnetic field having the strength of B=0.6 T has been used as an additional process parameter in order to suppress the establishment of pores while dispersing TiC particles in surface layers of aluminium alloys using a laser. The migration of hydrogen towards regions of high temperatures within the melting pool can lead to the creation of gas bubbles, therefore yielding pores after resolidification in the processed layer. This mechanism (known for instance in welding technologies of aluminium) could be suppressed by Lorentz-forces induced by an externally applied magnetic field. It could be shown experimentally that magnetic fields could assist laser surface treatment processes beneficially if higher beam powers were coupled in. This may be interesting if, for instance, thicker dispersed layers should be achieved.     

Interstitial Oxygen in Tin-Doped Indium Oxide Transparent Conductors

We report first-principles density functional theory calculations of interstitial oxygen in tin-doped indium oxide (ITO), a transparent conducting oxide. Interstitial oxygen plays a critical role in the defect of ITO because it is by removal of interstitial oxygen that n -type charge carriers are produced. The Frank and Köstlin defect model successfully rationalizes the observed conductivity, Sn-doping, and oxygen partial pressure dependencies of ITO by postulating that tin atoms, which substitute for indium, are clustered with interstitial oxygen. Structural evidence for such a clustering, however, remains ambiguous. Recently published Rietveld refinement results of X-ray and neutron diffraction data found interstitial oxygen to be significantly displaced (0.4 Å) from the ideal fourfold position. Our calculations show that the experimental position is plausible only if interstitial oxygen is clustered with Sn_In defects at any of the three d -type cation sites nearest to the interstitial, thereby providing direct structural confirmation of the Frank and Köstlin defect model.     

Benzo[k,l], xanthene–3, 4–dicarboximides and benzimidazoxanthenoisoquinolinones – yellow and orange dyes for synthetic–polymer fibres

Condensation of 4–chloro–l, 8–naphthalic anhydride with 2–nitrophenol afforded 4–(2–nitrophenoxy)–l, 8–naphthalic anhydride, which on reduction followed by Pschorr intramolecular cyclisation gave benzo[k, l]xanthene–3, 4–dicarboxylic acid anhydride. The identity of the product was confirmed by its alternative synthesis from 5–amino–4–phenoxy–l, 8–naphthalic anhydride. Benzo[k, l]xanthene–3, 4–dicarbox–ylic acid anhydride condensed with alkylamines or arylamines and with o–phenylenediamines to yield the corresponding imides and imidazole derivatives, which coloured polyester in fluorescent greenish–yellow to orange hues, respectively, of good fastness to light and sublimation. The colour of the dyes is discussed with respect to analogous ring–closed sulphur– containing heterocycles.