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991.
Patrick Emond Sylvie Mavel Nacima Aïdoud Lydie Nadal-Desbarats Frédéric Montigny Frédérique Bonnet-Brilhault Catherine Barthélémy Marc Merten Pierre Sarda Frédéric Laumonnier Patrick Vourc’h Hélène Blasco Christian R. Andres 《Analytical and bioanalytical chemistry》2013,405(15):5291-5300
Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders resulting from multiple factors. Diagnosis is based on behavioural and developmental signs detected before 3 years of age, and there is no reliable biological marker. The purpose of this study was to evaluate the value of gas chromatography combined with mass spectroscopy (GC-MS) associated with multivariate statistical modeling to capture the global biochemical signature of autistic individuals. GC-MS urinary metabolic profiles of 26 autistic and 24 healthy children were obtained by liq/liq extraction, and were or were not subjected to an oximation step, and then were subjected to a persilylation step. These metabolic profiles were then processed by multivariate analysis, in particular orthogonal partial least-squares discriminant analysis (OPLS-DA, R 2Y(cum) = 0.97, Q 2(cum) = 0.88). Discriminating metabolites were identified. The relative concentrations of the succinate and glycolate were higher for autistic than healthy children, whereas those of hippurate, 3-hydroxyphenylacetate, vanillylhydracrylate, 3-hydroxyhippurate, 4-hydroxyphenyl-2-hydroxyacetate, 1H-indole-3-acetate, phosphate, palmitate, stearate, and 3-methyladipate were lower. Eight other metabolites, which were not identified but characterized by a retention time plus a quantifier and its qualifier ion masses, were found to differ between the two groups. Comparison of statistical models leads to the conclusion that the combination of data obtained from both derivatization techniques leads to the model best discriminating between autistic and healthy groups of children. 相似文献
992.
993.
Carla Zanella Guidini Líbia Diniz Santos Marquez Helisângela de Almeida Silva Miriam Maria de Resende Vicelma Luiz Cardoso Eloízio Júlio Ribeiro 《Applied biochemistry and biotechnology》2014,172(3):1623-1638
Studies have been conducted on selecting yeast strains for use in fermentation for ethanol production to improve the performance of industrial plants and decrease production costs. In this paper, we study alcoholic fermentation in a fed-batch process using a Saccharomyces cerevisiae yeast strain with flocculant characteristics. Central composite design (CCD) was used to determine the optimal combination of the variables involved, with the sucrose concentration of 170 g/L, a cellular concentration in the inoculum of 40 % (v/v), and a filling time of 6 h, which resulted in a 92.20 % yield relative to the theoretical maximum yield, a productivity of 6.01 g/L h and a residual sucrose concentration of 44.33 g/L. With some changes in the process such as recirculation of medium during the fermentation process and increase in cellular concentration in the inoculum after use of the CCD was possible to reduce the residual sucrose concentration to 2.8 g/L in 9 h of fermentation and increase yield and productivity for 92.75 % and 9.26 g/L h, respectively. A model was developed to describe the inhibition of alcoholic fermentation kinetics by the substrate and the product. The maximum specific growth rate was 0.103 h?1, with K I and K s values of 109.86 and 30.24 g/L, respectively. The experimental results from the fed-batch reactor show a good fit with the proposed model, resulting in a maximum growth rate of 0.080 h?1. 相似文献
994.
995.
Marco Coïsson Luca Boarino Federica Celegato Natascia De Leo Paola Tiberto Franco Vinai 《Journal of nanoparticle research》2011,13(11):5641-5651
The exchange bias properties of nanopatterned thin films of Co, on top of which a native Co-oxide layer develops spontaneously,
are studied by means of magnetic and magneto-resistance measurements. Both continuous and patterned films are investigated,
the latter in the form of antidot arrays prepared with the self-assembling polystyrene nanospheres technique. The obtained
antidot arrays are in the hexagonal close-packed configuration and cover a surface area of several square millimetres. Nanopatterned
samples turn out to have a very good repeatability of their magnetic and magneto-resistive properties. The presence of a native
oxide is responsible for the development of an exchange bias effect at temperatures below ~150 K, which has been reported
both on hysteresis loops and on magneto-resistance curves; these consist of a superposition of an anisotropic magneto resistance
(AMR) effect and a giant magneto-resistance (GMR)-like effect. The determination of the bias field by means of the two different
sets of data is consistent and gives a complete picture of the phenomenology in this kind of nanopatterned magnetic systems. 相似文献
996.
In dimension d ≥ 3, we present a general assumption under which the renewal theorem established by Spitzer (1964) for i.i.d. sequences of centered nonlattice r.v. holds true. Next we appeal to an operator-type procedure to investigate
the Markov case. Such a spectral approach has been already developed by Babillot (Ann Inst Henri Poincaré, Sect B, Tome 24(4):507–569,
1988), but the weak perturbation theorem of Keller and Liverani (Ann Sc Norm Super Pisa CI Sci XXVIII(4):141–152, 1999) enables us to greatly weaken the moment conditions of Babillot (Ann Inst Henri Poincaré, Sect B, Tome 24(4):507–569, 1988). Our applications concern the v-geometrically ergodic Markov chains, the ρ-mixing Markov chains, and the iterative Lipschitz models, for which the renewal theorem of the i.i.d. case extends under
the (almost) expected moment condition. 相似文献
997.
We study the noncommutative geometrical structures of quantum entangled states. We show that the space of a pure entangled
state is a noncommutative space. In particular we show that by rewriting the coordinate ring of a conifold or the Segre variety
we can get a q-deformed relation in noncommutative geometry. We generalized our construction into a multi-qubit state. We also in detail
discuss the noncommutative geometrical structure of a three-qubit state. 相似文献
998.
We investigate the mechanisms involved in the funneling of optical energy into subwavelength grooves etched on a metallic surface. The key phenomenon is unveiled thanks to the decomposition of the electromagnetic field into its propagative and evanescent parts. We unambiguously show that the funneling is not due to plasmonic waves flowing toward the grooves, but rather to the magnetoelectric interference of the incident wave with the evanescent field, this field being mainly due to the resonant wave escaping from the groove. 相似文献
999.
Crassous A Bernard R Fusil S Bouzehouane K Le Bourdais D Enouz-Vedrenne S Briatico J Bibes M Barthélémy A Villegas JE 《Physical review letters》2011,107(24):247002
Using heterostructures that combine a large-polarization ferroelectric (BiFeO3) and a high-temperature superconductor (YBa2Cu3O(7-δ)), we demonstrate the modulation of the superconducting condensate at the nanoscale via ferroelectric field effects. Through this mechanism, a nanoscale pattern of normal regions that mimics the ferroelectric domain structure can be created in the superconductor. This yields an energy landscape for magnetic flux quanta and, in turn, couples the local ferroelectric polarization to the local magnetic induction. We show that this form of magnetoelectric coupling, together with the possibility to reversibly design the ferroelectric domain structure, allows the electrostatic manipulation of magnetic flux quanta. 相似文献
1000.
Brugnera L Hoffmann DJ Siegel T Frank F Zaïr A Tisch JW Marangos JP 《Physical review letters》2011,107(15):153902
We demonstrate control of short and long quantum trajectories in high harmonic emission through the use of an orthogonally polarized two-color field. By controlling the relative phase ? between the two fields we show via classical and quantum calculations that we can steer the two-dimensional trajectories to return, or not, to the core and so control the relative strength of the short or long quantum trajectory contribution. In experiments, we demonstrate that this leads to robust control over the trajectory contributions using a drive field from a femtosecond laser composed of the fundamental ω at 800 nm (intensity ~1.2×10(14) W?cm(-2)) and its weaker orthogonally polarized second harmonic 2ω (intensity ~0.3×10(14) W?cm(-2)) with the relative phase between the ω and 2ω fields varied simply by tilting a fused silica plate. This is the first demonstration of short and long quantum trajectory control at the single-atom level. 相似文献