738 research outputs found
Determination of low molecular weight volatiles in Ficus carica using HS-SPME and GC/FID
Ficus carica L. is one of the earliest cultivated fruit trees, having an important consumption in Mediterranean
countries. In this work, the volatile compound profiles of two characteristic Portuguese white varieties
(ââPingo de Melâ and ââBranca Tradicionalâ) was determined by HS-SPME and GC/FID. Leaves, pulps
and peels, submitted to freezing and lyophilisation treatments, were analysed.
The two varieties presented a similar profile composed of eight volatile compounds: acetaldehyde,
ethyl acetate, methanol, ethanol, hexanal, limonene, (E)-2-hexenal and octanal. The total volatile content
was different among the vegetal materials, following the order leaves > peels > pulps. Methanol and ethanol
are the major compounds in all samples.
The developed procedure revealed to be rapid, sensitive, reproducible and accurate. The detection limit
values were low, and the method precise. The recovery values for acetaldehyde, ethyl acetate, methanol
and ethanol were generally high, suggesting that it will be most suitable for compounds with low molecular
weight. Due to its rapidity and low cost, this technique can be useful in the quality control of fig fruit
and leaves
Magnetization steps in a diluted Heisenberg antiferromagnetic chain: Theory and experiments on TMMC:Cd
A theory for the equilibrium low-temperature magnetization M of a diluted
Heisenberg antiferromagnetic chain is presented. The magnetization curve, M
versus B, is calculated using the exact contributions of finite chains with 1
to 5 spins, and the "rise and ramp approximation" for longer chains. Some
non-equilibrium effects that occur in a rapidly changing B, are also
considered. Specific non-equilibrium models based on earlier treatments of the
phonon bottleneck, and of spin flips associated with cross relaxation and with
level crossings, are discussed. Magnetization data on powders of TMMC diluted
with cadmium [i.e., (CH_3)_4NMn_xCd_(1-x)Cl_3, with 0.16<=x<=0.50 were measured
at 0.55 K in 18 T superconducting magnets. The field B_1 at the first MST from
pairs is used to determine the NN exchange constant, J, which changes from -5.9
K to -6.5 K as x increases from 0.16 to 0.50. The magnetization curves obtained
in the superconducting magnets are compared with simulations based on the
equilibrium theory. Data for the differential susceptibility, dM/dB, were taken
in pulsed magnetic fields (7.4 ms duration) up to 50 T, with the powder samples
in a 1.5 K liquid-helium bath. Non-equilibrium effects, which became more
severe as x decreased, were observed. The non-equilibrium effects are
tentatively interpreted using the "Inadequate Heat Flow Scenario," or to
cross-relaxation, and crossings of energy levels, including those of excited
states.Comment: 16 pages, 14 figure
The southern photometric local universe survey (S-PLUS): Improved SEDs, morphologies, and redshifts with 12 optical filters
The Southern Photometric Local Universe Survey (S-PLUS) is imaging ~9300 deg2 of the celestial sphere in 12 optical bands using a dedicated 0.8mrobotic telescope, the T80-South, at the Cerro Tololo Inter-american Observatory, Chile. The telescope is equipped with a 9.2k Ă 9.2k e2v detector with 10 ÎŒm pixels, resulting in a field of view of 2 deg2 with a plate scale of 0.55 arcsec pixel-1. The survey consists of four main subfields, which include two non-contiguous fields at high Galactic latitudes (|b| > 30° , 8000 deg2) and two areas of the Galactic Disc and Bulge (for an additional 1300 deg2). S-PLUS uses the Javalambre 12-band magnitude system, which includes the 5 ugriz broad-band filters and 7 narrow-band filters centred on prominent stellar spectral features: the Balmer jump/[OII], Ca H + K, Hd, G band, Mg b triplet, Hα, and the Ca triplet. S-PLUS delivers accurate photometric redshifts (ÎŽz/(1 + z) = 0.02 or better) for galaxies with r < 19.7 AB mag and z < 0.4, thus producing a 3D map of the local Universe over a volume of more than 1 (Gpc/h)3. The final S-PLUS catalogue will also enable the study of star formation and stellar populations in and around the Milky Way and nearby galaxies, as well as searches for quasars, variable sources, and low-metallicity stars. In this paper we introduce the main characteristics of the survey, illustrated with science verification data highlighting the unique capabilities of S-PLUS. We also present the first public data release of ~336 deg2 of the Stripe 82 area, in 12 bands, to a limiting magnitude of r = 21, available at datalab.noao.edu/splus.Fil: De Oliveira, C. Mendes. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Ribeiro, T.. Universidade Federal de Sergipe; Brasil. National Optical Astronomy Observatory; Estados UnidosFil: Schoenell, W.. Universidade Federal do Rio Grande do Sul; BrasilFil: Kanaan, A.. Universidade Federal de Santa Catarina; BrasilFil: Overzier, R.A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; Brasil. MinistĂ©rio da CiĂȘncia, Tecnologia, Inovação e ComunicaçÔes. ObservatĂłrio Nacional; BrasilFil: Molino, A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Sampedro, L.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Coelho, P.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Barbosa, C.E.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Cortesi, A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Costa Duarte, M.V.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Herpich, F.R.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; Brasil. Universidade Federal de Santa Catarina; BrasilFil: Hernandez Jimenez, J.A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Placco, V.M.. University of Notre Dame; Estados Unidos. JINA Center for the Evolution of the Elements ; Estados UnidosFil: Xavier, H.S.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Abramo, L.R.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Saito, R.K.. Universidade Federal de Santa Catarina; BrasilFil: Chies Santos, A.L.. Universidade Federal do Rio Grande do Sul; BrasilFil: Ederoclite, A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; Brasil. Centro de Estudios de FĂsica del Cosmo de Aragon; EspañaFil: De Oliveira, R. Lopes. Universidade Federal de Sergipe; Brasil. MinistĂ©rio da CiĂȘncia, Tecnologia, Inovação e ComunicaçÔes. ObservatĂłrio Nacional; Brasil. University of Maryland; Estados UnidosFil: Goncalves, D.R.. Universidade Federal do Rio de Janeiro; BrasilFil: Akras, S.. MinistĂ©rio da CiĂȘncia, Tecnologia, Inovação e ComunicaçÔes. ObservatĂłrio Nacional; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Almeida, L.A.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; Brasil. Universidade Federal do Rio Grande do Norte; BrasilFil: Almeida Fernandes, F.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Beers, T.C.. University of Notre Dame; Estados Unidos. JINA Center for the Evolution of the Elements ; Estados UnidosFil: Bonatto, C.. Universidade Federal do Rio Grande do Sul; BrasilFil: Bonoli, S.. Centro de Estudios de FĂsica del Cosmo de Aragon; EspañaFil: Cypriano, E.S.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Vinicius Lima, E.. Universidade do Sao Paulo. Instituto de Astronomia, GeofĂsica e CiĂȘncias AtmosfĂ©ricas; BrasilFil: Smith Castelli, Analia Viviana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; Argentin
Evidence for geometry-dependent universal fluctuations of the Kardar-Parisi-Zhang interfaces in liquid-crystal turbulence
We provide a comprehensive report on scale-invariant fluctuations of growing
interfaces in liquid-crystal turbulence, for which we recently found evidence
that they belong to the Kardar-Parisi-Zhang (KPZ) universality class for 1+1
dimensions [Phys. Rev. Lett. 104, 230601 (2010); Sci. Rep. 1, 34 (2011)]. Here
we investigate both circular and flat interfaces and report their statistics in
detail. First we demonstrate that their fluctuations show not only the KPZ
scaling exponents but beyond: they asymptotically share even the precise forms
of the distribution function and the spatial correlation function in common
with solvable models of the KPZ class, demonstrating also an intimate relation
to random matrix theory. We then determine other statistical properties for
which no exact theoretical predictions were made, in particular the temporal
correlation function and the persistence probabilities. Experimental results on
finite-time effects and extreme-value statistics are also presented. Throughout
the paper, emphasis is put on how the universal statistical properties depend
on the global geometry of the interfaces, i.e., whether the interfaces are
circular or flat. We thereby corroborate the powerful yet geometry-dependent
universality of the KPZ class, which governs growing interfaces driven out of
equilibrium.Comment: 31 pages, 21 figures, 1 table; references updated (v2,v3); Fig.19
updated & minor changes in text (v3); final version (v4); J. Stat. Phys.
Online First (2012
Developing methods to compare tablet formulations of atorvastatin
Atorvastatin (ATV) is an antilipemic drug of great interest to the pharmaceutical industry. ATV does not appear in the monographs of Brazilian pharmacopoeia, and analytical methodologies for its determination have been validated. The chromatographic conditions used included: RP-18 column-octadecylsilane (250 x 4.6 mm, 5 mm), detection at 238 nm, mobile phase containing 0.1% phosphoric acid and acetonitrile (35:65% v/v), flow at 1.5 mL min-1, oven temperature at 30ÂșC, and injection volume of 10 mL. ATV is classified as a class II product, according to the biopharmaceutical classification system. As such, a dissolution test was proposed to evaluate pharmaceutical formulations on the market today, under the following conditions: water as a dissolution medium, 1000 mL as a volume, paddle apparatus at a rotation speed of 50 rpm, 80% (Q) in 15 minutes with UV spectrophotometer readings at 238 nm. In the pattern condition proposed as the ideal dissolution test, which appropriately differentiates amongst formulations, the generic product was not considered pharmaceutically equivalent; however, in other less differential dissolution methods, which also fall within appropriate legal parameters, this product could come to be regarded as generic.Atorvastatina (ATV) Ă© um fĂĄrmaco antilipĂȘmico de grande interesse para a indĂșstria farmacĂȘutica. ATV nĂŁo apresenta monografia na FarmacopĂ©ia Brasileira e metodologias analĂticas para sua determinação foram validadas. As condiçÔes cromatogrĂĄficas utilizadas foram: coluna RP-18-octadecilsilano (250 x 4.6 mm, 5 mm), detecção em 238 nm, fase mĂłvel contendo ĂĄcido fosfĂłrico 0,1% e acetonitrila (35:65% v/v), fluxo de 1,5 mL min-1, temperatura do forno de 30 ÂșC e volume de injeção de 10 mL. ATV Ă© classificada como um fĂĄrmaco de classe II, de acordo com o sistema de classificação biofarmacĂȘutica (SCB). Como tal, um teste de dissolução foi proposto para avaliar as formulaçÔes farmacĂȘuticas do mercado atual, sob as seguintes condiçÔes: ĂĄgua como meio de dissolução, volume de 1000 mL, aparato pĂĄ, velocidade de rotação de 50 rpm, 80% (Q) em 15 minutos com leituras espectrofotĂŽmetro UV a 238 nm. Na condição padrĂŁo proposta para o teste de dissolução, o qual seria capaz de diferenciar apropriadamente as formulaçÔes farmacĂȘuticas, o produto genĂ©rico nĂŁo foi considerado equivalente farmacĂȘutico. No entanto, em outros mĂ©todos de dissolução menos discriminativos, que tambĂ©m seriam considerados apropriados pelos parĂąmetros legais, este produto pode vir a ser considerado como genĂ©rico
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