613 research outputs found

    MS/MS studies on the selective on-line detection of sesquiterpenes using a Flowing Afterglow-Tandem Mass Spectrometer (FA-TMS)

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    A Flowing Afterglow-Tandem Mass Spectrometer (FA-TMS) was used to investigate the feasibility of selective on-line detection of a series of seven sesquiterpenes (SQTs). These SQTs were chemically ionized by either H3O+ or NO+ reagent ions in the FA, resulting among others in protonated SQT and SQT molecular ions, respectively. These and other Chemical Ionization (CI) product ions were subsequently subjected to dissociation by collisions with Ar atoms in the collision cell of the tandem mass spectrometer. The fragmentation spectra show similarities with mass spectra obtained for these compounds with other instruments such as a Proton Transfer Reaction-Linear Ion Trap (PTR-LIT), a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), a Triple Quadrupole-Mass Spectrometer (QqQ-MS) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS). Fragmentation of protonated SQT is characterized by fragment ions at the same masses but with different intensities for the individual SQT. Distinction of SQTs is based on well-chosen intensity ratios and collision energies. The fragmentation patterns of SQT molecular ions show specific fragment ion tracers at m/z 119, m/z 162, m/z 137 and m/z 131 for alpha-cedrene, delta-neoclovene, isolongifolene and alpha-humulene, respectively. Consequently, chemical ionization of SQT by NO+, followed by MS/MS of SQT(+) seems to open a way for selective quantification of SQTs in mixtures

    Description et modélisation de la croissance et du développement du pommier (Malus x domestica Borkh.) I. Structure la plus probable de l'arbre jeune

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    Description and modelisation of growth and development of appletree (Malus x domestica Borkh.). I. Most probable structure of young tree. Based on the observation of all or, at least, a large number of shoots growing on unpruned apple trees, cv. Cox's Orange Pippin and Jonagold grafted on EM9, an original codification system has been conceived. It allows to locate and identify quickly and unequivocally any shoot or growth. From a comprehensive collection of such codified observations, the most probable structure of young one to five year old trees has been established, with the amount and characters of the different observed shoot types. Both varieties display very similar gross structures, despite minor differences in form, flowering mode and productivity. The development of the trees occurs in two phases. The first one builds up a frame composed by the trunk and several storied sets of branches. Flowering is rather strictly alternate during this phase. The second one consists in the reinforcement of the branches by axillary growth, but even more by sympodial branching due to increasing and repeated terminal flowering. This basic structure provides a reference to appreciate changes in tree development brought about by rootstock, fruit load or training practices

    Almost sure existence of global weak solutions for super-critical Navier-Stokes equations

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    In this paper we show that after suitable data randomization there exists a large set of super-critical periodic initial data, in H−α(Td)H^{-\alpha}({\mathbb T}^d) for some α(d)>0\alpha(d) > 0, for both 2d and 3d Navier-Stokes equations for which global energy bounds are proved. As a consequence, we obtain almost sure super-critical global weak solutions. We also show that in 2d these global weak solutions are unique.Comment: 22 pages, a revised argument in Section 5, the d=3d=3 cas

    On the well-posedness for the Ideal MHD equations in the Triebel-Lizorkin spaces

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    In this paper, we prove the local well-posedness for the Ideal MHD equations in the Triebel-Lizorkin spaces and obtain blow-up criterion of smooth solutions. Specially, we fill a gap in a step of the proof of the local well-posedness part for the incompressible Euler equation in \cite{Chae1}.Comment: 16page

    The Beale-Kato-Majda criterion to the 3D Magneto-hydrodynamics equations

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    We study the blow-up criterion of smooth solutions to the 3D MHD equations. By means of the Littlewood-Paley decomposition, we prove a Beale-Kato-Majda type blow-up criterion of smooth solutions via the vorticity of velocity only, i. e. \sup_{j\in\Z}\int_0^T\|\Delta_j(\na\times u)\|_\infty dt, where Δj\Delta_j is a frequency localization on âˆŁÎŸâˆŁâ‰ˆ2j|\xi|\approx 2^j.Comment: 12page

    Blow-up of critical Besov norms at a potential Navier-Stokes singularity

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    We show that the spatial norm of any strong Navier-Stokes solution in the space X must become unbounded near a singularity, where X may be any critical homogeneous Besov space in which local existence of strong solutions to the 3-d Navier-Stokes system is known. In particular, the regularity of these spaces can be arbitrarily close to -1, which is the lowest regularity of any Navier-Stokes critical space. This extends a well-known result of Escauriaza-Seregin-Sverak (2003) concerning the Lebesgue space L3L^3, a critical space with regularity 0 which is continuously embedded into the spaces we consider. We follow the "critical element" reductio ad absurdum method of Kenig-Merle based on profile decompositions, but due to the low regularity of the spaces considered we rely on an iterative algorithm to improve low-regularity bounds on solutions to bounds on a part of the solution in spaces with positive regularity

    The effects of improving low dietary protein utilization on the proteome of lamb tissues

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    Cistus ladanifer L. is a common shrub endemic to the Mediterranean region with high levels of condensed tannins (CT). CT form complexes with dietary protein resisting microbial degradation in the rumen, which enhances dietary protein utilization in ruminant diets. The objective of this study was to evaluate the utilization of CT in the diet of lambs on the proteomes of muscle, hepatic and adipose tissues. Twenty-four Merino Branco ram lambs were randomly allocated to three treatments (n = 8): C – control (160 g crude protein (CP)) per kg DM, RP – reduced protein (120 g CP/kg DM); and RPCT – reduced protein (120 g CP/kg DM) treated with CT extract. At the end of the trial, lambs were slaughtered and the longissimus lumborum muscle, hepatic and peri-renal adipose tissues sampled. A two-way approach was used for proteomic analysis: 2D-DIGE and nanoLC-MS. In the muscle, C lambs had lower abundance proteins that partake in the glycolysis pathway than the lambs of other treatments. Control lambs had lower abundance of Fe-carrying proteins in the hepatic tissue than RP and RPCT lambs. The latter lambs had highest abundance of hepatic flavin reductase. In the adipose tissue, C lambs had lowest abundance of fatty-acid synthaseinfo:eu-repo/semantics/acceptedVersio
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