Droplet deformation and break-up under shear: Hydrocolloid solution vs. suspension of starch granules

Shear induced deformation and rupture of two types of droplets, hydroxypropyl methylcellulose (HPMC) aqueous solution and modified waxy maize suspension, were studied and compared using a counter-rotating rheo-optical set-up. The motivation of the work was to explain the difference observed in flavour perception of food products thickened by these two fluids. A droplet of either fluid was placed into silicon oil and deformation and break-up were monitored as a function of applied shear stress and strain. It was found that starch suspension droplets broke up at lower deformation stress and strain than HPMC solution droplets despite viscosity ratio and capillary number suggesting the opposite. It is hypothesised that the ease with which droplets thickened by starch break-up is responsible for their rapid mixing with saliva.     

Untersuchungen zum Abbau von Maillard-Reaktionsprodukten durch amylolytische Enzyme

The enzymatic degradation of thermal treated α-glucans with amylolytic enzymes depends on the reaction environment (T, pH, moisture), the degree of polymerisation (DP) and the branch of the substrates as well as on the presence of amino compounds. The chemical changes of the α-glucans due to thermolysis at 180 °C are characterized by means of the amount of reducing substances and the amount of maltooligosaccharides (HPLC). In general the enzymatic degradability of the thermal treated α-glucans is decreased with increasing time of thermolysis, temperature and moisture content. The enzyme activity with the thermal treated α-glucans is diminished in the same way. The addition of amino compounds reduces the enzymatic degradability only at the beginning of the reaction. With increasing time of thermolysis the thermolysates without glycine addition are hardly degradated. As reason for these differences in the enzymatic degradation transglycosylation and non-enzymatic browning reactions (caramalisation/ Maillard-reaction) are assumed.     

Large mass bolometric detectors for double-beta decay experiments

The authors have developed bolometric detectors with masses of 5.5 g, 20.9 g, and 34 g using TeO₂ crystals for the investigation of ¹³⁰Te, and are developing CaF₂ detectors for double-beta decay search in ⁴⁸Ca, using the luminescence properties of the crystal to improve background rejection. Scintillation of a CaF₂ crystal with 0.03% of Eu doping was observed at 20 mK. A 2.1-g, 0.01%-Eu-doped crystal was used as a bolometer, and a resolution of 50 keV for the double escape peak of ²³²Th was obtained at 60 mK, showing a negligible contribution of the Eu atoms to the crystal heat capacity. Simultaneous detection of light and phonons will allow an efficient background rejection of the ²³⁸U to ²³⁴Th α decay from the ²³⁸U natural series occurring at almost the same energy of the ⁴⁸Ca transition. Background rejection is necessary as even uranium contamination as low as 10^m-10 g/g would make the search impossible     

Volatile Emissions from Aesculus hippocastanum Induced by Mining of Larval Stages of Cameraria ohridella Influence Oviposition by Conspecific Females

Larval stages of the horse chestnut leafminer Cameraria ohridella can completely destroy the surface of horse chestnut leaves, Aesculus hippocastanum. This study investigated the effect of the degree of leaf browning caused by the insect’s larvae on olfactory detection, aggregation, and oviposition of C. ohridella adults. The influence of A. hippocastanum flower scent on oviposition of the first generation was also evaluated. Utilizing gas chromatography coupled with parallel detection by mass spectrometry and electroantennography (GC-MS/EAD), more than 30 compounds eliciting responses from antennae of C. ohridella were detected. Oviposition and mining by C. ohridella caused significant changes in the profile of leaf volatiles of A. hippocastanum. After oviposition and subsequent mining by early larval stages (L1–L3), substances such as benzaldehyde, 1,8-cineole, benzyl alcohol, 2-phenylethanol, methyl salicylate, (E)-β-caryophyllene, and (E,E)-α-farnesene were emitted in addition to the compounds emitted by uninfested leaves. Insects were able to detect these compounds. The emitted amount of these substances increased with progressive larval development. During late larval stages (L4, L5) and severe loss of green leaf area, (E,E)-2,4-hexadienal, (E/Z)-linalool oxide (furanoid), nonanal, and decanal were also released by leaves. These alterations of the profile of volatiles caused modifications in aggregation of C. ohridella on leaves. In choice tests, leaves in early infestation stages showed no significant effect on aggregation, whereas insects avoided leaves in late infestation stages. Further choice tests with leaves treated with single compounds led to the identification of substances mediating an increase or decrease in oviposition.     

Photocaged Hoechst Enables Subnuclear Visualization and Cell Selective Staining of DNA in vivo

Selective targeting of DNA by means of fluorescent labeling has become a mainstay in the life sciences. While genetic engineering serves as a powerful technique and allows the visualization of nucleic acid by using DNA-targeting fluorescent fusion proteins in a cell-type- and subcellular-specific manner, it relies on the introduction of foreign genes. On the other hand, DNA-binding small fluorescent molecules can be used without genetic engineering, but they are not spatially restricted. Herein, we report a photocaged version of the DNA dye Hoechst33342 (pcHoechst), which can be uncaged by using UV to blue light for the selective staining of chromosomal DNA in subnuclear regions of live cells. Expanding its application to a vertebrate model organism, we demonstrate uncaging in epithelial cells and short-term cell tracking in vivo in zebrafish. We envision pcHoechst as a valuable tool for targeting and interrogating DNA with precise spatiotemporal resolution in living cells and wild-type organisms.     

The potential limitations on its basin decision-making processes of granting self-defence rights to Father Rhine

ABSTRACT

Recent grants of legal rights to rivers would seem to infuse traditional anthropocentric river governance with greater eco-centrism. Through a thought experiment, we scrutinize this proposition for the Rhine basin. We consider the governance implications of granting (procedural/material) rights to the river and elaborate on their implications for the three highly institutionalized regimes of the Rhine River of water quality, flooding and transport. Since we find that a shift to more eco-centrism has already occurred and since the right granted to the river would not be absolute, we deem radical transformations unlikely.     

Swiss Rainfall Mass Curves and their Influence on Extreme Flood Simulation

Extreme flood estimates for dam safety are routinely obtained from hydrologic simulations driven by selected design storms. The temporal structure of such design storms can be obtained from Rainfall Mass Curves (RMCs), which are adimensionalized curves of the cumulative precipitation depth as a function of event duration. This paper assesses for the first time the spatialand temporal variability of observed RMCs for Switzerland, an Alpine region with complex topography. The relevance of the detected RMC variability for extreme flood estimation is illustrated based on an application to a high elevation catchment, the Mattmark dam catchment in the Swiss Alps. The obtained results underline that quantile RCMs represent a simple yet powerful tool to construct design storms for dam safety verification and that regional, seasonal and event-duration effects on RMCs are small enough to justify the use of a unique set of Swiss-wide quantile RMCs. The presented analysis could be refined in the future by explicitly accounting for orographic, convective or frontal precipitation events.     

The periodic tableau: Form and colours in the first 100 years

While symbolic colour use has always played a conspicuous role in science research and education, the use of colour in historic diagrams remains a lacuna in the history of science. Investigating the colour use in diagrams often means uncovering a whole cosmology that is not otherwise explicit in the diagram itself. The periodic table is a salient and iconic example of non‐mimetic colour use in science. Andreas von Antropoff's (1924) rectangular table of recurrent rainbow colours is famous, as are Alcindo Flores Cabral's (1949) application of colour in his round snail form, using the RGB scheme, and Mazurs's (1967) pine tree system, consisting of warm and cold colours that he attributed to specific groups of elements—an attribution that we can relate back to humoralism and alchemy. From the first periodic tables in the 19th century, individual researchers have used different colour regimes. While standardization may play an obvious role in chemistry and its diagrams, all the more impressive is the anarchistic use of colour in the various diagrams which continue to be created. This article focuses on periodic tables in chemical journals and text books, and explores and compares the development of colour codes found in the few existing polychrome diagrams from the 1920s to the 1970s.