Effects of N-application on utilization of 15N and 13C and quality in two wheat cultivars

We studied N uptake and distribution in wheat, and the incorporation of nitrogen and carbon into gluten and non-gluten proteins using a double-labelling approach with 15N and 13C. Doses of N-fertilizer were split and applied at emergence, onset of stem elongation, and heading at rates of 280/140/140 mg N pot(-1), respectively simulating 90/45/45 kg N ha(-1). Five different combinations of N-fertilizations containing no or 10 % 15N were performed. The recovery of 15N added at the stages emergence, stem elongation or heading were 42, 60, and 64 %. Application of 15N at all three stages yielded in 51 % recovery. Remobilisation of straw N was greater for Golia. The 15N concentration in gluten proteins of Golia show higher values than Gonen. The ratio of 15N gluten/15N non-gluten proteins of Golia were higher, which implies a lower non-gluten protein activity during grain filling. The 13C concentration in gluten and non-gluten proteins did not differ between both cultivars.     

Critical Effect of Film Thickness on Preconcentration Electroanalysis with Oriented Mesoporous Silica Modified Electrodes

Electrogenerated silica thin films exhibiting a regular hexagonal packing of vertically‐aligned mesopore channels are promising for preconcentration electroanalysis. This work demonstrates the critical role of film thickness on their sensing performance using paraquat as a model analyte, based on mesoporous silica films prepared by electrochemically assisted self‐assembly performed for various deposition times. Films prepared with too short synthesis times (<10 s) led to deposits covering partially the electrode surface and suffered from rather poor sensing performance. Then, uniformly deposited films were obtained (between 10 and 15 s), and sensitivity rose up by increasing deposition times, whereas some limitations started to occur with much thicker films (>15 s deposition times) as a result of less electrochemically accessible paraquat accumulated far away from the electrode surface and restricted mass transport through the whole film thickness. These limitations were also confirmed on the basis of multi‐layered mesoporous silica films, suggesting a behavior that might be typical for other types of film‐modified electrodes.     

Loading‐Dependent Structural Model of Polymeric Micelles Encapsulating Curcumin by Solid‐State NMR Spectroscopy

Detailed insight into the internal structure of drug‐loaded polymeric micelles is scarce, but important for developing optimized delivery systems. We observed that an increase in the curcumin loading of triblock copolymers based on poly(2‐oxazolines) and poly(2‐oxazines) results in poorer dissolution properties. Using solid‐state NMR spectroscopy and complementary tools we propose a loading‐dependent structural model on the molecular level that provides an explanation for these pronounced differences. Changes in the chemical shifts and cross‐peaks in 2D NMR experiments give evidence for the involvement of the hydrophobic polymer block in the curcumin coordination at low loadings, while at higher loadings an increase in the interaction with the hydrophilic polymer blocks is observed. The involvement of the hydrophilic compartment may be critical for ultrahigh‐loaded polymer micelles and can help to rationalize specific polymer modifications to improve the performance of similar drug delivery systems.     

Comparative measurements of loudspeakers in a listening situation

Comparison of loudspeakers is a major concern during design or product selection. There are several standards for the measurement of loudspeaker characteristics, but none of them provides hints for a rigorous comparison between devices. In this study, different ways of evaluating acoustical dissimilarity between loudspeakers were compared. Several methods of signal analysis were used, and for each method a metric evaluating the dissimilarity between two signals was defined. The correlation between the different dissimilarity evaluations over a significant panel of loudspeakers led to identified classes of measurements. A specific aspect of this work is that measurements were performed in a standard listening environment, rather than in an anechoic or reverberant one. It allowed the use of the recorded signals for a simple listening test, providing a perceptual metric which was compared to the acoustical ones. It also allowed the introduction of auditory models in the computation of some acoustical metrics, so defining a new class of measurements which gave results close to the perceptual ones.     

Tobramycin and Nebramine as Pseudo‐oligosaccharide Scaffolds for the Development of Antimicrobial Cationic Amphiphiles

Antimicrobial cationic amphiphiles derived from aminoglycoside pseudo‐oligosaccharide antibiotics interfere with the structure and function of bacterial membranes and offer a promising direction for the development of novel antibiotics. Herein, we report the design and synthesis of cationic amphiphiles derived from the pseudo‐trisaccharide aminoglycoside tobramycin and its pseudo‐disaccharide segment nebramine. Antimicrobial activity, membrane selectivity, mode of action, and structure–activity relationships were studied. Several cationic amphiphiles showed marked antimicrobial activity, and one amphiphilic nebramine derivative proved effective against all of the tested strains of bacteria; furthermore, against several of the tested strains, this compound was well over an order of magnitude more potent than the parent antibiotic tobramycin, the membrane‐targeting antimicrobial peptide mixture gramicidin D, and the cationic lipopeptide polymyxin B, which are in clinical use.     

Spectral,electrochemical and computational investigations on the host–guest interaction of Coumarin-460 with <Emphasis Type="Italic">p</Emphasis>-sulfonatocalix[4]arene

The supramolecular host–guest investigation of Coumarin 460 (C460), a salient coumarin family dye molecule is studied with a noteworthy host molecule, p-sulfonatocalix[4]arene (p-SC4). The investigation is carried out by both experimental and theoretical approach. The binding affinity of C460 with p-SC4 is experimentally studied using absorption, emission, excited state lifetime and Cyclic Voltammetry methods. The binding constant is around 10³ M^??1, which shows potent binding. The binding stoichiometry is 1:1. The binding orientations and binding energies are studied using computational simulations. The mode of binding is also established using NMR spectral techniques.     

The Ziegler Spectrum of a Locally Coherent Grothendieck Category

The general theory of locally coherent Grothendieck categoriesis presented. To each locally coherent Grothendieck categoryC a topological space, the Ziegler spectrum of C, is associated.It is proved that the open subsets of the Ziegler spectrum ofC are in bijective correspondence with the Serre subcategoriesof coh C the subcategory of coherent objects of C. This is aNullstellensatz for locally coherent Grothendieck categories.If R is a ring, there is a canonical locally coherent Grothendieckcategory RC (respectively, CR) used for the study of left (respectively,right) R-modules. This category contains the category of R-modulesand its Ziegler spectrum is quasi-compact, a property used toconstruct large (not finitely generated) indecomposable modulesover an artin algebra. Two kinds of examples of locally coherentGrothendieck categories are given: the abstract category theoreticexamples arising from torsion and localization and the examplesthat arise from particular modules over the ring R. The dualitybetween coh-(RC) and coh-CR is shown to give an isomorphismbetween the topologies of the left and right Ziegler spectraof a ring R. The Nullstellensatz is used to give a proof ofthe result of Crawley-Boevey that every character : K₀(coh-C) Z is uniquely expressible as a Z-linear combination of irreduciblecharacters. 1991 Mathematics Subject Classification: 16D90,18E15.