Effect of moisture on salmonella spp. heat resistance in cocoa and hazelnut shells

The heat resistance of food-poisoning outbreak and non-outbreak associated strains of Salmonella (S. Enteritidis, S. Montevideo, S. Napoli, S. Oranienburg, S. Poona, S. Senftenberg and S. Typhimurium) was established in confectionery-related materials such as crushed cocoa bean and hazelnut shells at low moisture contents (≤ 4% w/w). The two most heat resistant strains in cocoa and hazelnut shells at ca. 4% w/w moisture were S. Oranienburg and S. Enteritidis PT30. Both strains were associated with outbreaks from dried materials. Their D_100°C values were ca. 2.5 min in crushed cocoa bean shells and 7–11 min in crushed hazelnut shells. Addition of moisture to ca. 7% w/w markedly reduced D-values (D_80°C of 2–4.5 min) for both strains in the two matrices.     

Smart ultrasonic sensors systems: potential of aluminum nitride thin films for the excitation of the ultrasound at high frequencies

We investigated the potential of the aluminum nitride films to excite ultrasonic waves at frequencies >50?MHz. The deposition process of the aluminum nitride thin film layers on silicon substrates was investigated and optimized regarding their piezoelectric behavior. Large single element transducers were deposited on silicon substrates with aluminum electrodes, under different parameters for the magnetron sputter process, like pressure and bias voltage. Special test setup and a measuring station were created to characterize the sensors. Acoustical measurements were carried out in pulse echo mode up to 500?MHz and the values of piezoelectric charge constant (d₃₃) were determined. As a result, two parameter sets were found for the sputtering process to obtain an excellent piezoelectric charge constant of about 7.2?pC/N maximum. Then the sputtering process with these parameters was used to deposit sensors on various substrate materials and with different electrode sizes.     

Gas Chromatographic Enantiomer Separation of Polychlorinated Biphenyls (PCBs): Methods,Metabolisms, Enantiomeric Composition in Environmental Samples and their Interpretation

The year 2016 not only marks the 50^th anniversary of the first successful discovery of gas chromatographic (GC) enantiomer separations in 1966 by Gil-Av, but also the less appraised 50^th anniversary of the discovery of polychlorinated biphenyls (PCBs) in the environment. This article reports on GC enantiomer separations of axially stable, chiral PCBs (PCB atropisomers) with modified cyclodextrins. Nineteen atropisomeric PCBs exist, but most data exists for four PCB atropisomers (PCB 95, PCB 132, PCB 149, and PCB 136), which can be resolved without significant coelutions on three columns coated with modified cyclodextrins. Nonracemic compositions of PCB atropisomers and their hydroxylated metabolites have been documented in various studies. However, the measured enantiomer fractions are currently difficult to interpret und understand. The most plausible reasons for these difficulties are discussed and interpreted with the help of selected examples from the literature.     

Execution profiling blueprints

Although traditional approaches to code profiling help locate performance bottlenecks, they offer only limited support for removing these bottlenecks. The main reason is the lack of detailed visual runtime information to identify and eliminate computation redundancy. We provide three profiling blueprints that help identify and remove performance bottlenecks. The structural distribution blueprint graphically represents the CPU consumption share for each method and class of an application. The behavioral distribution blueprint depicts the distribution of CPU consumption along method invocations and hints at method candidates for caching optimizations. The behavioral evolution blueprint compares profiles of different versions of a software system and highlights performance‐critical changes in the system. These three blueprints helped us to significantly optimize Mondrian, an open source visualization engine. Our implementation is freely available for the Pharo development environment and has been evaluated in a number of different scenarios. Copyright © 2011 John Wiley & Sons, Ltd.     

Insect adhesion on rough surfaces: analysis of adhesive contact of smooth and hairy pads on transparent microstructured substrates

Insect climbing footpads are able to adhere to rough surfaces, but the details of this capability are still unclear. To overcome experimental limitations of randomly rough, opaque surfaces, we fabricated transparent test substrates containing square arrays of 1.4 µm diameter pillars, with variable height (0.5 and 1.4 µm) and spacing (from 3 to 22 µm). Smooth pads of cockroaches (Nauphoeta cinerea) made partial contact (limited to the tops of the structures) for the two densest arrays of tall pillars, but full contact (touching the substrate in between pillars) for larger spacings. The transition from partial to full contact was accompanied by a sharp increase in shear forces. Tests on hairy pads of dock beetles (Gastrophysa viridula) showed that setae adhered between pillars for larger spacings, but pads were equally unable to make full contact on the densest arrays. The beetles'' shear forces similarly decreased for denser arrays, but also for short pillars and with a more gradual transition. These observations can be explained by simple contact models derived for soft uniform materials (smooth pads) or thin flat plates (hairy-pad spatulae). Our results show that microstructured substrates are powerful tools to reveal adaptations of natural adhesives for rough surfaces.