High performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI-MS-MS) for the quantification of L-kynurenine and indole-3-acetic acid in grape must by isotope dilution assay

Isotope dilution assay was used for the qualitative and quantitative analysis of L-kynurenine and indole-3-acetic acid in grape must. After solid phase extraction, highest selectivity and sensitivity was achieved by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS-MS) using selected reaction monitoring (SRM). In the 24 samples under study, the amounts of L-kynurenine and indole-3-acetic acid ranged from 0 to 94 mu g.l-1 and from 20 to 380 mu g.l-1, respectively. These compounds are considered as potential precursors of 2-aminoacetophenone, causing the ''untypical aging off-flavour'' in Vitis vinifera white wines

Variation of the frictional anisotropy on ventral scales of snakes caused by nanoscale steps

The ventral scales of most snakes feature micron-sized fibril structures with nanoscale steps oriented towards the snake\u27s tail. We examined these structures by microtribometry as well as atomic force microscopy (AFM) and observed that the nanoscale steps of the micro-fibrils cause a frictional anisotropy, which varies along the snake\u27s body in dependence of the height of the nanoscale steps. A significant frictional behavior is detected when a sharp AFM tip scans the nanoscale steps up or down. Larger friction peaks appear during upward scans (tail to head direction), while considerably lower peaks are observed for downward scans (head to tail direction). This effect causes a frictional anisotropy on the nanoscale, i.e. friction along the head to tail direction is lower than in the opposite direction. The overall effect increases linearly with the step height of the micro-fibrils. Although the step heights are different for each snake, the general step height distribution along the body of the examined snakes follows a common pattern. The frictional anisotropy, induced by the step height distribution, is largest close to the tail, intermediate in the middle, and lower close to the head. This common distribution of frictional anisotropy suggests that snakes even optimized nanoscale features like the height of micro-fibrils through evolution in order to achieve optimal friction performance for locomotion. Finally, ventral snake scales are replicated by imprinting their micro-fibril structures into a polymer. As the natural prototype, the artificial surface exhibits frictional anisotropy in dependence of the respective step height. This feature is of high interest for the design of tribological surfaces with artificial frictional anisotropy

Potentially pathogenic micro-organisms originating from manure-processing plants in the air

Mestbewerkingsinstallaties bewerken het overschot aan mest. In dierlijke mest kunnen bacteriën of virussen zitten. Het is niet bekend in hoe ver de installaties deeltjes uitstoten die schadelijk zijn voor de gezondheid. Omwonenden maken zich daar zorgen om. Het RIVM werkt daarom aan een monitoringsprogramma om ziekteverwekkende organismen te kunnen meten in de buitenlucht rondom deze installaties. De eerste stap is daar nu in gemaakt. Het RIVM doet dit in opdracht van de provincie Noord-Brabant. Het is veel werk om alle mogelijke ziekteverwekkers te meten in lucht rondom mestverwerkingsinstallaties. Bepaalde groepen ziekteverwekkers gedragen zich hetzelfde in mest en in lucht. Het RIVM heeft daarom uitgezocht welke organismen verschillende groepen ziekteverwekkende bacteriën en virussen kunnen vertegenwoordigen. Als deze ‘indicatoren’ in de lucht zitten, kan gericht in kaart worden gebracht welke ziekteverwekkers uit de installaties komen. De voorgestelde indicatoren zijn de bacteriën Campylobacter, Clostridium, E. coli, enterokokken en endotoxine. Somatische colifagen zijn een indicator voor virussen. Het RIVM adviseert ook met welke methoden het beste de uitstoot van de gekozen indicatoren kunnen worden gemeten. Het RIVM adviseert om luchtmetingen op meerdere afstanden van de installaties te doen. Veel ziekteverwekkers sterven namelijk snel af in de buitenlucht. Als er ziekteverwekkers in de lucht zitten, zullen die aantallen op grotere afstand van een installatie kleiner zijn.Manure-processing plants process surplus manure. Animal manure can contain bacteria and/or viruses. Although it is not known whether these plants release infectious agents that are harmful to people's health, local residents are concerned about this issue. RIVM is therefore working on a monitoring program for measuring pathogenic organisms originating from processed manure in the air outside these plants and this report provides the first step to this end. RIVM was commissioned by the Province of North-Brabant to carry out this research. Measuring all the pathogens that may be present in air around manure treatment plants is a laborious task. However, certain groups of infectious agents behave similarly in manure and air. For this reason, RIVM has investigated which organisms could be good representatives of the various groups of pathogenic bacteria and viruses. If these ‘indicators’ are present in the air, the pathogens that originate from the plants can be identified more efficiently. The identified indicators are endotoxin and the bacteria Campylobacter, Clostridium, E. coli and Enterococci. Somatic coliphages are an indicator for the presence of viruses. RIVM also advises on which methods can best be used to measure the release of the indicators chosen. RIVM recommends that air measurements be taken at varying distances from the plants in question because many pathogens die rapidly in the outside air. If there are pathogens in the air, the numbers at greater distances from a plant would be expected to be lower.Provincie Noord-Braban

Design and usage of a process-centric collaboration methodology for virtual organizations in hybrid environments

This article describes a collaboration methodology for virtual organizations where the processes can be automatically executed using a hybrid web service, grid or cloud resources. Typically, the process of deriving executable workflows from process models is cumbersome and can be automated only in part or specific to a particular distributed system. The approach introduced in this paper, exemplified by the construction industry field, integrates existing technology within a process-centric framework. The solution on the basis of a hybrid system architecture in conjunction with semantic methods for consistency saving and the framework for modeling VO processes and their automated transformation and execution are discussed in detail

Revealing the nature of photoluminescence emission in the metal-halide double perovskite Cs2AgBiBr6

Double perovskite crystals such as Cs2AgBiBr6 are expected to overcome the limitation of classic hybrid organic–inorganic perovskite crystals related to the presence of lead and the lack of structural stability. Perovskites are ionic crystals in which the carriers are expected to strongly couple to lattice vibrations. In this work we demonstrate that the photoluminescence (PL) emission in Cs2AgBiBr6 is strongly influenced by the strong electron–phonon coupling. Combining photoluminescence excitation (PLE) and Raman spectroscopy we show that the PL emission is related to a color center rather than a band-to-band transition. The broadening and the Stokes shift of the PL emission from Cs2AgBiBr6 is well explained using a Franck–Condon model with a Huang–Rhys factor of S = 11.7 indicating a strong electron–phonon interaction in this material.</p

Revealing the nature of photoluminescence emission in the metal-halide double perovskite Cs2AgBiBr6

Double perovskite crystals such as Cs2AgBiBr6andnbsp;are expected to overcome the limitation of classic hybrid organicandndash;inorganic perovskite crystals related to the presence of lead and the lack of structural stability. Perovskites are ionic crystals in which the carriers are expected to strongly couple to lattice vibrations. In this work we demonstrate that the photoluminescence (PL) emission in Cs2AgBiBr6andnbsp;is strongly influenced by the strong electronandndash;phonon coupling. Combining photoluminescence excitation (PLE) and Raman spectroscopy we show that the PL emission is related to a color center rather than a band-to-band transition. The broadening and the Stokes shift of the PL emission from Cs2AgBiBr6andnbsp;is well explained using a Franckandndash;Condon model with a Huangandndash;Rhys factor ofandnbsp;Sandnbsp;= 11.7 indicating a strong electronandndash;phonon interaction in this material.</p