Dimensioning of membrane bioreactors for municipal wastewater treatment.

A basic procedure is proposed for dimensioning membrane bioreactors that is generally applicable. It evaluates the required membrane surface with particular consideration of loading combinations and hydraulic loading characteristics; it also takes into account ranges of minimum temperatures and corresponding fluxes as given by suppliers. The procedures, while likely to require further improvement, should make MBR design more transparent and aid the comparison of design variants.     

Preparation of defined bulk densities for using the capillary rise method in the case of fine powders

The wetting properties of powders are important in many technological processes. Contact angles can be characterized by an effective contact angle of the particle arrangement relative to the wetting liquid, but their quantification is problematic. An exact determination depends on an accurate preparation of the test samples. A defined pre-consolidation by vertical shocks is introduced in this paper.     

Simplified Calculation of Mixing and Suspending Processes in Agitated Vessels – Part II: Examples of Application

Mixing processes in agitated vessels with different stirring systems are simulated using a cell model. The model takes the fluid velocity and fluid turbulence, as well as the diffusion and the sedimentation velocity of the particles into account. The two‐ and three‐dimensional behaviors of single particles and collectives of particles in the vessels, respectively, are discussed in terms of different aspects. The calculated concentration distributions are compared with some measurements from the literature. Furthermore, a user interface developed for the calculation program, is introduced.     

On measuring nondeterminism in regular languages

It is well known that allowing nondeterminism in a finite automaton can produce in the most extreme case an exponential savings in the number of states required to recognize a regular language. This paper studies situations intermediate between forbidding nondeterminism and allowing it. The amount of nondeterminism used by a finite automaton is quantified, so that the decrease in the size of the state space that occurs as the amount of nondeterminism that is permitted increases in increments can be studied. These intermediate situations are shown always to lie between two extremes:(1) there are no savings as the amount of nondeterminism increases incrementally, so that savings occur only when the amount of nondeterminism becomes unlimited;(2) each increment of nondeterminism results in additional savings, the number s of states decreasing approximately as s^1/i, until exponential savings have been achieved after about i = logs/log log s increments.     

Trees,grids, and MSO decidability: From graphs to matroids

Monadic second order (MSO) logic has proved to be a useful tool in many areas of application, reaching from decidability and complexity to picture processing, correctness of programs and parallel processes. To characterize the structural borderline between decidability and undecidability is a classical research problem here. This problem is related to questions in computational complexity, especially to the model checking problem, for which many tools developed in the area of decidability have proved to be useful. For more than two decades it was conjectured in [D. Seese, The structure of the models of decidable monadic theories of graphs, Ann. Pure Appl. Logic 53 (1991) 169–195] that decidability of monadic theories of countable structures implies that the theory can be reduced via interpretability to a theory of trees.     

Rapid differentiation of new apple cultivars by headspace solid‐phase microextraction in combination with chemometrical data processing

The aim of this study was to test a combination of automated headspace solid phase‐microextraction gas chromatography (GC) with chemometrical data treatment for the rapid differentiation of enzyme‐inactivated homogenates of new apple cultivars. The four cultivars Pinova, Piflora, Renora and Florina are characterized by different volatile patterns. Differences in the contents of volatiles were especially found for butyl acetate, ethyl butanoate, 2‐methyl butanol, ethyl acetate and 6‐methyl‐5‐hepten‐2‐ol. The used sample preparation method for GC coupled with pattern recognition of chromatograms is a useful tool for rapid and reliable determination of large numbers of samples.     

Production of pullulan

Optimum conditions for the production of pullulan by Pullularia pullulans were elaborated by examinating growth and production with different carbohydrates and mixtures of carbohydrates. With starch hydrolysates or mixtures of starch and simple sugars, p.e. glucose or saccharose, better results were achieved than with simple sugars alone or with starch. Condtions for optimum pullulan production are fast undisturbed growth, mediated by fast utilizable simple sugars like glucose followed by a substantial decreased growth rate in which production occurs, mediated by a sufficient supply of nutrite substances and a slow utilizable carbohydrate like starch.     

The Function of the Histamine H4 Receptor in Inflammatory and Inflammation-Associated Diseases of the Gut

Histamine is a pleiotropic mediator involved in a broad spectrum of (patho)-physiological processes, one of which is the regulation of inflammation. Compounds acting on three out of the four known histamine receptors are approved for clinical use. These approved compounds comprise histamine H1-receptor (H₁R) antagonists, which are used to control allergic inflammation, antagonists at H₂R, which therapeutically decrease gastric acid release, and an antagonist at H₃R, which is indicated to treat narcolepsy. Ligands at H₄R are still being tested pre-clinically and in clinical trials of inflammatory diseases, including rheumatoid arthritis, asthma, dermatitis, and psoriasis. These trials, however, documented only moderate beneficial effects of H₄R ligands so far. Nevertheless, pre-clinically, H₄R still is subject of ongoing research, analyzing various inflammatory, allergic, and autoimmune diseases. During inflammatory reactions in gut tissues, histamine concentrations rise in affected areas, indicating its possible biological effect. Indeed, in histamine-deficient mice experimentally induced inflammation of the gut is reduced in comparison to that in histamine-competent mice. However, antagonists at H₁R, H₂R, and H₃R do not provide an effect on inflammation, supporting the idea that H₄R is responsible for the histamine effects. In the present review, we discuss the involvement of histamine and H₄R in inflammatory and inflammation-associated diseases of the gut.