Perceptual denoising of color images

Denoising of color images is a trade‐off between sharpness of an image and perceived noise. We formulate a novel optimization problem that can maximize sharpness of an image while limiting the perceived noise under a model of visibility of additive random noise. We derive a closed‐form expression for an optimal two‐dimensional finite impulse response filter, show its uniqueness and existence, and present simulation results for black and white as well as color images. Simulation results show remarkable reduction in perceptibility of noise, while preserving sharpness. The computational burden required for the optimal filter is reduced by a new adhoc filter which is simple but has near optimal performance. © 2010 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 20, 215–222, 2010.     

Towards validation and refinement of rule-based systems

A methodology for the validation of rule-based expert systems is presented as a multi-step process that has three central themes: (1) creation of a useful set of test inputs that cover the domain; (2) a methodology that evaluates the system's responses to the test inputs and compares it to the responses of a panel of human experts; and (3) use of the validation results for system refinement. The presented methodology is performed in a loop. The starting point is a rule base and the loop ends up in a (hopefully) better rule base. The first three steps of this process have been published as separate issues in earlier papers by the authors. Here, these issues are just outlined and references are provided for detailed information. This paper gives an overview of the entire process and describes the relation between its steps. The last step, system refinement, is the new scientific issue here and thus, presented in more detail. Here, the rules are modified according to the results of evaluating the test cases. The base of this rule base reconstruction is both a 'rule-associated validity' and the existence of a 'better rated' human solution.     

Novel Approach to Switched Controller Design for Linear Continuous‐Time Systems

In this paper, we study a novel approach to the design of an output feedback switched controller with an arbitrary switching algorithm for continuous‐time invariant systems that is described by a novel plant model as a gain‐scheduled plant using the multiple quadratic stability and quadratic stability approaches. In the proposed design procedure, there is no need to use the notion of the "dwell time". The obtained results are in the form of bilinear matrix inequalities (BMI). Numerical examples show that, in the proposed method, the design procedure is less conservative and gives more possibilities than that described in the papers published previously.     

Erneuerung der Eisenbahnüberführung in Fulda‐Horas über die Fulda

A new rail bridge crosses the River Fulda in Fulda‐Horas. The rail connection between Gießen and Fulda crosses the Fulda River in the town of Fulda‐Horas. It replaces the three‐span tressle bridge design that was over 100 years old. The new bridge consists of only two spans, broadening each span. The following article describes the key visible construction features of the steel superstructure. The new bridge was built at an elevation of approximately 10 meters and parallel to the old one. A critical review of the design assisted in a faster‐than‐planned construction and lower costs.     

DNA carryover in milk samples from routine milk recording used for PCR-based diagnosis of bovine Staphylococcus aureus mastitis

Real-time PCR techniques are increasingly used to detect udder pathogens from milk samples collected non-aseptically at routine milk recording. The objectives of this study were (1) to estimate the statistical associations between cycle threshold (Ct) values for Staphylococcus aureus in non-aseptically collected composite samples taken at routine milk recording from cows milked consecutively with the same milking unit and milk meter; and (2) to formulate practical and plausible guidelines for understanding the diagnostic implications of PCR testing for Staph. aureus intramammary infection at routine milk recording. The study included 4 herds with conventional milking parlors and repeatedly low Ct-values for Staph. aureus (representing a high DNA load) in bulk tank milk. Composite milk samples were collected from all cows at all milking units during routine milk recording using the Tru-Test electronic milk meter (Tru-Test Group, Auckland, New Zealand) and analyzed using the PathoProof PCR (Thermo Fisher Scientific, Vantaa, Finland) assay. Milking clock times were retrieved at each milk meter to establish the milking order of the cows at each unit. A multinomial logistic regression was applied to estimate the association between Ct-values from cows milked consecutively with the same milking unit and milk meter. The following groups were selected based on Ct-values: (1) 0–31.3, (2) 31.4–33.9, (3) 34.0–37, (4) 37.1–39.9, and (5) 40 (negative result). The association between groups from cows milked consecutively with the same milking unit and milk meter was statistically significant. Approximately 60% of cows were in Ct group 5 if the antecedent cow was also in Ct group 5, but only 20% of cows were in Ct group 5 if the antecedent cow was in Ct group 1. The probability of cows being in Ct group 1 was not markedly influenced by the group of the antecedent cow. Statistical relationships in the intermediate range gave a plausible indication of a dose-response relationship. Carryover of bacterial DNA via the milking unit and milk meter is very likely to affect PCR results for Staph. aureus. Therefore, information about milking order must be considered in mastitis control efforts. We suggest a practical interpretation of PCR results: cows with a Ct-value <32 can be labeled “very likely to be infected with Staph. aureus,” but cows with Ct-values of >37 and 32–37 can be labeled “very likely to be negative for Staph. aureus” and “uncertain Staph. aureus status,” respectively.     

Zona pellucida as physiological trigger for the induction of acrosome reaction

To evaluate the kinetics of acrosome reaction, sperm samples from four fertile donors were prepared by swim-up and incubated with solutions of human zonae containing 0.1, 0.15, 0.3, 0.5 and 1.0 zonae microliter-1. After 20, 40 and 60 min of incubation at 37 degrees C, aliquots were taken for evaluation of the acrosomal status. The results showed a distinct time- and dose dependence of the acrosome reaction induced by solubilized zona proteins. After 60 min of incubation in 1.0 zonae microliter-1, about 80% of the spermatozoa showed signs of acrosomal loss; about 40% were completely acrosome-reacted. In addition, zona-bound sperm showed the same ratios of acrosome-reacted spermatozoa in control experiments. The velocity of acrosome reaction was calculated by means of a double-reciprocal plot being 2.0-2.5% min-1 for completely reacted spermatozoa and those showing signs of acrosome reaction. However, both subgroups differed considerably in their constants of equilibrium (K = 2.0 ZP microliter-1 and K = 0.2 ZP microliter-1, respectively). In nonreacted and partly reacted spermatozoa results might indicate a disturbed course of acrosome reaction or possibly the existence of different subpopulations in respect of sperm competition.     

Vorwort

Ohne Zusammenfassung     

Investigation of gliadin binding to different selected proteins using a biotin-streptavidin system

Using a biotin streptavidin system 12 out of 19 different test proteins were found to bind to gliadin, with casein, fibrinogen, and fibronectin showing the strongest association. Binding was demonstrable using different gliadin subfractions and enzymatic digests. There was no consistent effect of several carbohydrates on binding. Binding of most proteins to gliadin was diminished slightly by removal of Ca²⁺ and strongly by dioxane, ethylene glycol, Triton X-100, and Tween 20. The results suggest a non-selective association between gliadin and the proteins investigated, mainly due to hydrophobic interactions, which might be of significance in intestinal pathobiochemistry, e. g. disease.

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Untersuchung der Bindung von Gliadin an unterschiedliche ausgewählte Proteine in einem Biotin-Streptavidin-System

Zusammenfassung Unter Verwendung eines Biotin-Streptavidin-Systems konnte bei 12 von 19 Testproteinen eine Bindung an Gliadin festgestellt werden, wobei Casein, Fibrinogen und Fibronectin die stärkste Assoziation zeigten. Die Bindung war an unterschiedlichen Gliadinsubfraktionen und-digestaten nachweisbar. Verschiedene Kohlenhydrate hatten keinen beständigen Effekt auf die Bindung. Die Bindung der meisten Proteine an Gliadin wurde durch Entfernung von Ca²⁺ leicht und durch Dioxan, Ethylenglycol, Triton X-100 und Tween 20 stark verringert. Die Ergebnisse weisen auf eine unselektive Bindung im wesentlichen infolge hydrophober Interaktionen zwischen Gliadin und den untersuchten Proteinen hin, die auch für die intestinale Pathobiochemie (Zöliakie) bedeutsam sein könnte.

     

Effect of Surface Coating on the Photocatalytic Function of Hybrid CdS–Au Nanorods

Hybrid semiconductor–metal nanoparticles are interesting materials for use as photocatalysts due to their tunable properties and chemical processibility. Their function in the evolution of hydrogen in photocatalytic water splitting is the subject of intense current investigation. Here, the effects of the surface coatings on the photocatalytic function are studied, with Au‐tipped CdS nanorods as a model hybrid nanoparticle system. Kinetic measurements of the hydrogen evolution rate following photocatalytic water reduction are performed on similar nanoparticles but with different surface coatings, including various types of thiolated alkyl ligands and different polymer coatings. The apparent hydrogen evolution quantum yields are found to strongly depend on the surface coating. The lowest yields are observed for thiolated alkyl ligands. Intermediate values are obtained with L‐glutathione and poly(styrene‐co‐maleic anhydride) polymer coatings. The highest efficiency is obtained for polyethylenimine (PEI) polymer coating. These pronounced differences in the photocatalytic efficiencies are correlated with ultrafast transient absorption spectroscopy measurements, which show a faster bleach recovery for the PEI‐coated hybrid nanoparticles, consistent with faster and more efficient charge separation. These differences are primarily attributed to the effects of surface passivation by the different coatings affecting the surface trapping of charge carriers that compete with effective charge separation required for the photocatalysis. Further support of this assignment is provided from steady‐state emission and time‐resolved spectral measurements, performed on related strongly fluorescing CdSe/CdS nanorods. The control and understanding of the effect of the surface coating of the hybrid nanosystems on the photocatalytic processes is of importance for the potential application of hybrid nanoparticles as photocatalysts.