Water dynamics in hectorite clays: influence of temperature studied by coupling neutron spin echo and molecular dynamics

Within the wider context of water behavior in soils, and with a particular emphasis on clays surrounding underground radioactive waste packages, we present here the translational dynamics of water in clays in low hydrated states as studied by coupling molecular dynamics (MD) simulations and quasielastic neutron scattering experiments by neutron spin echo (NSE). A natural montmorillonite clay of interest is modeled by a synthetic clay which allows us to understand the determining parameters from MD simulations by comparison with the experimental values. We focus on temperatures between 300 and 350 K, i.e., the range relevant to the highlighted application. The activation energy Ea experimentally determined is 6.6 kJ/mol higher than that for bulk water. Simulations are in good agreement with experiments for the relevant set of conditions, and they give more insight into the origin of the observed dynamics.     

Pesticide adsorption in relation to soil properties and soil type distribution in regional scale

Study was focused on the evaluation of pesticide adsorption in soils, as one of the parameters, which are necessary to know when assessing possible groundwater contamination caused by pesticides commonly used in agriculture. Batch sorption tests were performed for 11 selected pesticides and 13 representative soils. The Freundlich equations were used to describe adsorption isotherms. Multiple-linear regressions were used to predict the Freundlich adsorption coefficients from measured soil properties. Resulting functions and a soil map of the Czech Republic were used to generate maps of the coefficient distribution. The multiple linear regressions showed that the K(F) coefficient depended on: (a) combination of OM (organic matter content), pH(KCl) and CEC (cation exchange capacity), or OM, SCS (sorption complex saturation) and salinity (terbuthylazine), (b) combination of OM and pH(KCl), or OM, SCS and salinity (prometryne), (c) combination of OM and pH(KCl), or OM and ρ(z) (metribuzin), (d) combination of OM, CEC and clay content, or clay content, CEC and salinity (hexazinone), (e) combination of OM and pH(KCl), or OM and SCS (metolachlor), (f) OM or combination of OM and CaCO(3) (chlorotoluron), (g) OM (azoxystrobin), (h) combination of OM and pH(KCl) (trifluralin), (i) combination of OM and clay content (fipronil), (j) combination of OM and pH(KCl), or OM, pH(KCl) and CaCO(3) (thiacloprid), (k) combination of OM, pH(KCl) and CEC, or sand content, pH(KCl) and salinity (chlormequat chloride).     

Zur Querkraftgefährdung bestehender Spannbetonbrücken

Zur Formulierung einer Handlungsanweisung wurden in Teil I die geänderten Lastannahmen für Brücken nach DIN Fachbericht 101 mit den Belastungsklassen nach alten Normen verglichen und gezeigt, wie anhand aktueller Verkehrszahlen die Lastansätze modifiziert werden können. Der aktuelle Brückenbestand in Hessen wurde mit der Straßeninformationsbank (Teilprojekt Bauwerksdaten) ausgewertet, um Klassifizierungs‐ und Bewertungskriterien zu erarbeiten. Zur Beurteilung des Querkraftwiderstandes wurden die Grundlagen der Querkraftbemessung nach DIN 1045, DIN 4227, DIN Fachbericht 102 und aus der Literatur gegenübergestellt. In Teil II werden Verfahren zur nachträglichen Verstärkung von Querschnitten und Tragsystemen mit zu geringer Querkrafttragfähigkeit zusammengestellt. Des Weiteren werden verschiedene Varianten der Modellierung verglichen, die bei der linearelastischen Schnittgrößenermittlung nach der Finite‐Elemente‐ Methode verwendet werden. Auf Grundlage der gewonnenen Erkenntnisse werden schließlich Empfehlungen für eine Handlungsanweisung zur Beurteilung querkraftgefährdeter Brückenbauwerke formuliert. Shear‐Vulnerability of Existing Pre‐Stressed Concrete Bridges In Part I, to formulate an operation directive the revised load assumptions for bridges of DIN Technical Report 101 are compared with the loading classes according to old standards and it is demonstrated, how the loading models can be modified based on actual traffic data. The current bridge asset in the Federal State of Hesse is evaluated using the “Road Information Database (Sub‐Project: Structural Data)” in order to work out classification and evaluation criteria. Regarding the assessment of the shear load‐bearing capacity the fundamentals of the shear load design models of DIN 1045, DIN 4227, DIN TR 102 and from the literature are compared. In Part II, the procedures for the subsequent strengthening of cross‐sections and structural systems with a low shear load‐bearing capacity are compiled. In addition, different types of finite element modelling are compared used for the calculation of the linear‐elastic internal forces. Finally, based on the findings recommendations are formulated for an operation directive in regard to the assessment of shear‐vulnerable bridges.     

A comparative study of quality and safety of Atlantic cod (Gadus morhua) fillets during cold storage,as affected by different thawing methods of pre‐rigor frozen headed and gutted fish

BACKGROUND

The catch of marine whitefish is typically seasonal, whereas the land‐based processing industry has a need for all‐year stable supply of raw materials. This challenge can be met by applying fish frozen at sea. When using frozen fish, the methods employed for thawing may influence the safety and quality of the final product. This study aimed to investigate the applicability of novel thawing strategies in order to provide an all‐year supply of high‐quality and safe cod products.

RESULTS

Comparative investigations of quality and safety factors after thawing in water, with and without air circulation, and contact thawing were performed. The parameters included water‐holding capacity, thawing loss, drip loss, cooking yield, sensory evaluation and microbiological analyses (including total volatile bases nitrogen). Water thawing with air circulation provided faster thawing than water thawing without air circulation and contact thawing. For all three methods, the quality of the thawed fish was acceptable and the shelf life of the fillets during chilled storage was between 10 and 14 days post‐filleting.

CONCLUSION

The results show that controlled freezing of cod, followed by appropriate thawing, may provide the processing industry with an all‐year delivery of raw materials, without compromising quality and safety of the final product. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Synthesis of Cholesterol‐Substituted Glycopeptides for Tailor‐Made Glycocalyxification of Artificial Membrane Systems

Synthetic minimal membrane systems are extremely useful for better understanding of complex cellular structures and cell surface processes. We have developed a facile method for synthesis of cholesterylated peptides, each bearing a carbohydrate moiety and a fluorescent tag. The position of the cholesterol moiety on the peptide can be controlled by using a new Fmoc‐protected cholesterol‐triazole‐lysine group, which we constructed by means of solid‐phase peptide synthesis. We succeeded in integrating the glyco modules into giant unilamellar vesicles by electroformation or infusion in buffer solution. The glyco‐decorated liposomes were recognized by a lectin and had unique topological membrane features. In conclusion, this work is a proof of principle for the functionalization of artificial membranes with a primitive synthetic glycocalyx useful for studying carbohydrate–protein interactions on a simplified cell‐like membrane surface.     

Corrigenda

Supersaturated designs and associated analysis methods have been proposed by several authors to identify active factors in situations in which only a very limited number of experimental runs is available. We use simulation to evaluate the abilities of the existing methods to achieve model identification–related objectives. The results motivate a new class of supersaturated designs, derived from simulation optimization, that maximize the probability that stepwise regression will identify the important main effects. Because the proposed designs depend on specific assumptions, we also investigate the sensitivity of the performances of the alternative supersaturated designs to these assumptions.     

Models for Rod and Bar Rolling Mills with 2‑roll, 3‑roll,and 4‑roll Stands

For the quality of rolled products, a perfect surface quality and tight, close tolerances apart from defined mechanical properties are essential. One key condition is a perfect pass design in the rolling mill. The paper deals with the models for a pass design calculation as well as a calculation of roll force and power demands for the rolling mill. On modern bar and rod mill, different types of mill stands are used, with 2?roll, 3?roll, and 4?roll stands. For each of these stand types, a special model system is used for the calculation. Heat balance and temperature control by water cooling are the basis for thermomechanical rolling to achieve the desired mechanical properties of the material. Free size rolling and the compensation of the numerous influencing parameters on the product dimensions must be incorporated in a pass design.     

硫氧化还原酶热稳定性的结构基础(英文)

The thermostability of three sulfur oxygenase reductases(SORs) was investigated from thermoaci-dophilic achaea Acidianus tengchongensis(SORAT) and Sulfolobus tokodaii(SORST) as well as the moderately thermophilic bacterium Acidithiobacillus sp.SM-1(SORSB).The optimal temperatures for catalyzing sulfur oxida-tion were 80 °C(SORAT),85 °C(SORST),and 70 °C(SORSB),respectively.The half-lives of the three SORs at their optimal catalytic conditions were 100 min(SORAT),58 min(SORST),and 37 min(SORSB).In order to reveal the structural basis of the thermostability of these SORs,three-dimensional structural models of them were generated by homology modeling using the previously reported high-resolution X-ray structure of SORAA(from Acidianus ambivalens) as a template.The results suggest that thermostability was dependent on:(a) high number of the charged amino acid glutamic acid and the flexible amino acid proline,(b) low number of the thermolabile amino acid glutamine,(c) increased number of ion pairs,(d) decreased ratio of hydrophobic accessible solvent surface area(ASA) to charged ASA,and(e) increased volumes of the cavity.The number of cavities and the number of hydro-gen bonds did not significantly affect the thermostability of SORs,whereas the cavity volumes increased as the thermal stability increased.