In vivo XANES measuring technique for studying the arsenic uptake in cucumber plants

New in vivo X‐ray absorption near edge structure measuring technique was developed by using liquid nitrogen steam flow for cooling cucumber samples keeping them under cryogenic conditions during the measurement in order to preserve the original chemical states of arsenic species in the hypocotyl. The aim of this study was to determine the As oxidation state in order to identify the possible metabolic processes during the nutrient uptake in cucumber (Cucumis sativus L. cv Joker) as model plant. The plants were grown in Hoagland's modified nutrient solution. The ratio of the quantity of two As species was determined in the hypocotyls of the cucumber samples: arsenite, As(III) and arsenate, As(V). The ultimate biological goal of the in vivo experiments was to investigate the applicability of the X‐ray absorption near edge structure technique under cryogenic conditions and to specify the resistance level of the plants to arsenic toxicity when different chemical forms of iron, FeCl₃ and Fe‐ascorbate were supplied in the nutrient solution. We have examined the influence of the intense synchrotron radiation beam on the transformation of the oxidation number of both As species when the effect of the reactive oxygen forms was eliminated by the presence of ascorbate. Copyright © 2016 John Wiley & Sons, Ltd.     

Micellization behavior of aromatic moiety bearing hybrid fluorocarbon sulfonate surfactants

Aggregation behavior and thermodynamic properties of two novel homologous aromatic moiety bearing hybrid fluorocarbon surfactants, sodium 2-(2-(4-ethylphenyl)-1,1,2,2-tetrafluoroethoxy)-1,1,2,2-tetrafluoroethanesulfonate (1) and sodium 2-(1,1,2,2-tetrafluoro-2-(4-vinylphenyl)ethoxy)-1,1,2,2-tetrafluoroethanesulfonate (2) were studied using surface tension measurements and isothermal titration calorimetry (ITC) in dilute aqueous solutions at room temperature. Because of the aromatic group in the hydrophobic tail, both surfactants are soluble at room temperature unlike their starting precursor, 5-iodooctafluoro-3-oxapentanesulfonate as well as several other fluorocarbon sulfonic acid salts. Moreover, the surfactant 2 has the ability that it can be polymerized once microemulsions are formed with it. The ionic conductivity measurements of 1 at five different temperatures from 288 to 313 K were carried out to study the effect of temperature on the micellization and its thermodynamics. The pseudophase separation model was applied to estimate thermodynamic quantities from conductivity data. The Gibbs energy of micellization versus temperature exhibited the characteristic U-shaped behavior with a minimum at 306 K. The micellization process was found to be largely entropy driven. Because of its hybrid structure, the entropy change of micellization for 1 was larger than what is common for hydrocarbon surfactants like SDS but less than for fully fluorinated surfactants like NaPFO. The micellization process was found to be following the entropy-enthalpy compensation phenomena.     

Orthogonalities in linear spaces and difference operators

Summary. Quite recently C. Alsina, P. Cruells and M. S. Tomás [2], motivated by F. Suzuki's property of isosceles trapezoids, have proposed the following orthogonality relation in a real normed linear space (X, ||·||) (X, \Vert \cdot \Vert) : two vectors x,y ? X x,y \in X are T-orthogonal whenever¶||z-x ||² + ||z-y ||² = ||z ||² + ||z-(x+y) ||² \Vert z-x \Vert^2 + \Vert z-y \Vert^2 = \Vert z \Vert^2 + \Vert z-(x+y) \Vert^2 ¶for every z ? X z \in X . A natural question arises whether an analogue of T-orthogonality may be defined in any real linear space (without a norm structure). Our proposal reads as follows. Given a functional j \varphi on a real linear space X we say that two vectors x,y ? X x,y \in X are j \varphi -orthogonal (and write x^_jy x\perp_{\varphi}y ) provided that D_x,yj = 0 \Delta_{x,y}\varphi = 0 (D_h1,h2 \Delta_{h_1,h_2} stands here and in the sequel for the superposition D_h1 °D_h2 \Delta_{h_1} \circ \Delta_{h_2} of the usual difference operators).¶We are looking for necessary and/or sufficient conditions upon the functional j \varphi to generate a j \varphi -orthogonality such that the pair X,^_j X,\perp_{\varphi} forms an orthogonality space in the sense of J. Rätz (cf. [6]). Two new characterizations of inner product spaces as well as a generalization of some results obtained in [2] are presented.     

Interfacial Microcompartmentalization by Kinetic Control of Selective Interfacial Accumulation

Reported here is a 2D, interfacial microcompartmentalization strategy governed by 3D phase separation. In aqueous polyethylene glycol (PEG) solutions doped with biotinylated polymers, the polymers spontaneously accumulate in the interfacial layer between the oil-surfactant-water interface and the adjacent polymer phase. In aqueous two-phase systems, these polymers first accumulated in the interfacial layer separating two polymer solutions and then selectively migrated to the oil-PEG interfacial layer. By using polymers with varying photopolymerizable groups and crosslinking rates, kinetic control and capture of spatial organisation in a variety of compartmentalized macroscopic structures, without the need of creating barrier layers, was achieved. This selective interfacial accumulation provides an extension of 3D phase separation towards synthetic compartmentalization, and is also relevant for understanding intracellular organisation.     

Resonant trapping of scattered light in a degenerate resonator

We demonstrate and discuss the formation of an intriguing interference fringe pattern that is visible in stable resonators at resonator lengths corresponding to a higher-order frequency-degeneracy. The optical trajectories that form these fringes are described for arbitrary degeneracy; the fringes can be used to visualize and quantify imaging aberrations of the cavity relative to a cavity consisting of ideal mirrors.     

Comparison of quantum mechanical and semiclassical cross sections for rotational excitation of hydrogen

Partial and integral cross sections for rotational transitions in He  H₂ have been calculated by a semiclassical coupled states method. The agreement with corresponding quantum mechanical values is excellent.     

A regenerable immobilized nadh model IV: Reduction of pyridine-2-carbaldehyde by immobilized 1,4-dihydronicotinamide in the presence of Mg2+ ions

Dihydronicotinamide, anchored to a macroreticular polystyrene resin, reduces pyridine-2-carbaldehyde (PCA) in the presence of Mg²⁺ ions in acetonitrile. The reactions are clean at room temperature, the high rate precluding complications arising from slow side reactions. The influence of Mg²⁺ concentration on the rate of reduction of PCA by polymer-bound reagent and BNAH (1-benzyl-1,4-dihydronicotinamide; low-molar-mass analog) has been studied. Analysis of the kinetic data showed that of the processes contributing to the overall reduction, the reaction between the reductant and the complexed substrate proceeded at the highest rate. In the polymer-bound reagent, “site isolation” on the rigid matrix was observed to prevent bimolecular disproportionation of the neighboring dihydronicotinamides. Regeneration of the polymeric reagent was achieved with an efficiency of 98% per cycle.     

A local intercomparison study of ESR dosimetry using tooth enamel

Using electron spin resonance (ESR), tooth enamel is a possible dosimeter in case of a radiation accident. To check the present status of this technique, we conducted a local intercomparison study. We irradiated several samples of tooth enamel with a⁶⁰Co source. Three institutes in Belgium and The Netherlands recorded the ESR signal of the samples. The results of the measurements and the methods used are compared. It is concluded that ESR on tooth enamel can be a useful technique in accident dosimetry, provided further research is done.