Control strategies for reactive processes involving vibrationally hot product states

We present an all optical control mechanism for the switching process in fulgides via electronically excited states in the presence of conical intersections. The underlying photoreaction is the ring opening or closure of the central C₆-ring chromophore. The control of this reaction is realized with shaped laser pulses which are obtained by Optimal Control Theory. Our implementation of the algorithm enables the definition of a target in the electronic ground state even if vibrationally hot product states are formed during the reaction demanding the appliance of a damping function. We introduce a flexible target definition including all parts of the wavepacket that will reach the target region within a given time interval T. Thereby the localization of the wavepacket inside this region at a specific point in time is not mandatory. A target definition in the ground state facilitates the comparability to experiments. With this target, the control algorithm favors an all optical process which is faster than the relaxation through the conical intersections. To enhance the possibility of experimental realizations, we analyze the optimized pump–dump sequence to allow a reconstruction and simplification of the laser field.     

Determination of Cry9C protein in processed foods made with StarLink corn

StarLink (Aventis CropScience US) hybrid corn has been genetically modified to contain a pesticidal protein, Cry9C, which makes it more resistant than traditional varieties to certain types of corn insect pests. Unlike other varieties of genetically engineered corn, the U.S. Environmental Protection Agency authorized the use of StarLink corn for animal feed and industrial use only, not for human consumption. However, some Cry9C-containing corn was mistakenly or inadvertently comingled with yellow corn intended for human food use. Because corn containing the Cry9C construct was not approved for human use, the U.S. Food and Drug Administration considers food containing it to be adulterated. Consequently, this regulatory violation resulted in hundreds of recalls of corn-based products, such as taco shells, containing cry9C DNA. Detecting the novel protein in StarLink corn is an emerging issue; therefore, there is no standardized or established analytical method for detecting Cry9C protein in processed foods. We developed a procedure for quantitation of Cry9C protein, with validation data, in processed food matrixes with a limit of quantitation at 1.7 ng/g (ppb), using a commercial polyclonal antibody-based Cry9C kit that was intended for corn grain samples. Intra- and interassay coefficients of variation were 2.8 and 11.8%, respectively. Mean recoveries were 73 and 85% at 2 and 5 ng/g Cry9C fortifications, respectively, for 19 control non-StarLink corn-based matrixes. Our data demonstrate only 0-0.5% of Cry9C protein survived the processing of tortilla chips and soft tortillas made from 100% StarLink corn, resulting in levels from below the detection limit to 45 ppb.     

Phytotoxic metabolites by nine species of Botryosphaeriaceae involved in grapevine dieback in Australia and identification of those produced by Diplodia mutila,Diplodia seriata,Neofusicoccum australe and Neofusicoccum luteum

Botryosphaeria dieback is one of the main trunk diseases of grapevine caused by several species of Botryosphaeriaceae. Twenty-four fungal isolates representing the eight most widespread and most virulent Botryosphaeriaceae were tested for their ability to produce phytotoxic metabolites. The chromatographic profiles of their culture filtrates organic extracts showed the ability of all isolates to produce several and different metabolites. When tested on grapevine leaves and tomato cuttings the organic extracts phytotoxicity varied among isolates and species. To our knowledge, this is the first study on phytotoxic compounds produced by Botryosphaeriaceae species found in Australian vineyards. The phytotoxic metabolites produced by Diplodia seriata, Diplodia mutila, Neofusicoccum australe and, for the first time, by Neofusicoccum luteum were isolated and chemically identified essentially by spectroscopic methods.

     

Immobilized enzymes - A simple calorimetric method for the determination of the catalytic activity

The results communicated in this paper show that rapid and reliable information about the activity of immobilized enzymes follows from calorimetric measurements. The study was done using spherical and plain carriers as well as different enzymes (urease, glucose-oxidase, invertase). The enzyme thermistor developed by Danielsson et al. was used as a measuring system. This measuring system was applied to investigate the activity of enzyme carrier complexes produced by the sol-gel technique. The influence of processing parameters could be pointed out at complexes of different forms (xerogel, gel on ceramic carrier, thin gel layers on foil, etc.). With the described calorimetric method, a fast and reliable technique for comparative determination of the activity of immobilized enzymes is available. A special advantage of this method is its variability in carriers and the generally applicable thermal measuring principle. Therefore, it seems useful for the development of new immobilization techniques.     

Preparation, characterization and crystal structure of Na4[Mn(NCS)6]·13H2O

Na₄[Mn(NCS)₆] · 13H₂O was prepared and characterized by chemical analysis, magnetic susceptibility, thermal dehydration reactions, and single crystal X-ray structure analysis. The crystals are triclinic with a=9.310(1)Å, b=9.367(1)Å, c=9.730(2)Å, = 89.89(1)°,=75.33(1)°, =70.72(1)°, space group P¯I.Z=1. The structure is built up from Na(H₂O)₅ S, Na(H₂O)₆, and Mn(NCS)₆, octahedra. All water molecules are coordinated to Na⁺ -ions in terminal as well as bridging fashion. They form O-H···O as well as O-H···S hydrogen bonds.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Monosaccharides and the VO(IV) metal ion: Equilibrium,thermal studies and hypoglycemic effect

Protonation and complexation equilibriums of monosaccharides and the VO(IV) metal ion in aqueous solution were studied as well as their effect on the hyperglycemia of diabetic rats. The complexes formed were characterized by potentiometric titrations, paramagnetic resonance spectroscopy (EPR) and thermogravimetric–differential scanning calorimetry (TGA–DSC). The system involving d-gluconic acid (HGlu) and oxovanadium(IV) (VO²⁺) was chosen to study the serum glucose levels in alloxan-induced diabetic rats. A binuclear species was detected in small quantities, which was formed by coordination of two HGlu molecules and two VO²⁺ ions through a hydroxide bridge. The mononuclear species formed by HGlu and VO²⁺ were confirmed by EPR. The anisotropic spectra obtained from aqueous frozen solutions (77 K) are characteristic of mononuclear VO-hexoses. The cyclic sugars d-ribone-1,4-lactone (Riblac), d-galactone-1,4-lactone (Galac) and 2-deoxy-d-glucopyranose (dGlu) showed weak interactions with the metal ion and they are not able to hold the metal in solution above pH 4.6 resulting in hydrolysis of the metal ion. Also, the acute treatment with sugar complexes of HGlu–VO led to a significant hypoglycemic effect (23% and 18% by intraperitoneal or oral gavage treatment, respectively) in diabetic rats. These results show the potential effectiveness of VO–HGlu complexes as anti-hyperglycemic agents through intraperitoneal injection in alloxan-induced diabetic rats.     

Arrowroot starch-based films incorporated with a carnauba wax nanoemulsion,cellulose nanocrystals,and essential oils: a new functional material for food packaging applications

Arrowroot starch (AA)-based films incorporated with a carnauba wax nanoemulsion (CWN), cellulose nanocrystals (CNCs), and essential oils (EOs) from Mentha spicata (MEO) and Cymbopogon martinii (CEO) were produced using the casting technique and then characterized in terms of their water barrier, tensile, thermal, optical, and microstructural properties and in vitro antifungal activity against Rhizopus stolonifer and Botrytis cinerea. Whereas the incorporation of CNCs decreased the moisture content and water vapor permeability of the AA/CWN/CNC film, the additional incorporation of either EO decreased the transparency and affected the microstructure of the AA/CWN/CNC/EO nanocomposites. MEO and CEO incorporation improved the thermal stability of the films and provided excellent protection against fruit-spoiling fungi. Because of their excellent barrier properties against fungal growth, water vapor permeability, and ultraviolet and visible light, these AA/CWN/CNC/EO films have promising potential for application as active food packaging or coating materials.

Graphic abstract

     

Germanium and silicon compounds as promoters for Re2O7/SiO2-Al2O3 metathesis catalysts

The effect of replacement of R₄Sn by germanium and silicon derivatives as the promoter for the catalyst system Re₂O₇/SiO₂-Al₂O₃ in the metathesis of hex-1-ene, and the system Re₂O₇/B₂O₃/SiO₂-Al₂O₃ in the metathesis of methyl oleate, was studied. The new promoters react slowly with the rhenium oxide. An activation time of about 15 min at temperatures varying from 50 to 75 °C is required for obtaining a good catalytic activity. These promoters can replace the toxic tin compounds, although they give rise to lower turnover numbers in the metathesis of methyl oleate.     

Direct measurement of lithium in whole blood using microchip capillary electrophoresis with integrated conductivity detection

The direct measurement of lithium in whole blood is described. Using microchip capillary electrophoresis (CE) with defined sample loading and applying the principles of column coupling, alkali metals were determined in a drop of whole blood. Blood collected from a finger stick was mixed with anticoagulant and transferred onto the chip without extraction or removal of components. The electrokinetic transport of red blood cells inside the channels was studied to find sample loading conditions suitable for the analysis of lithium without injecting cells into the separation channel. Both bare glass chips and chips coated with polyacrylamide were used showing the behavior of the cells under different electroosmotic flow conditions. In serum a detection limit for lithium of 0.4 mmol/L was reached. Proteins quickly contaminated untreated chip surfaces but devices with coating gave reproducible electropherograms. In addition, potassium and sodium were also detected in the same separation run. To our knowledge, this is the first device to directly measure ions in whole blood with the use of capillary zone electrophoresis on a microchip.     

Line Hypergraphs: A Survey

The survey is devoted to line graphs and a new multivalued function called the line hypergraph. This function generalizes two classical concepts at once, namely the line graph and the dual hypergraph. In a certain sense, line graphs and dual hypergraphs are extreme values of the function . There are many publications about line graphs, but our considerations are restricted to papers concerning Krausz global characterization of line graphs or Whitneys theorem on edge isomorphisms. The survey covers almost all known results on the function because they are concentrated around Krausz and Whitneys theorems. These results provide evidence that the notion of the line hypergraph is quite natural. It enables one to unify the classical theorems on line graphs and to obtain their more general versions in a simpler way.