933 research outputs found
Atividade antioxidante e compostos fenólicos de cinco acessos de pimentas Capsicum chinense.
Pimentas além de serem popularmente utilizadas como condimentos, representam uma fonte significativa de compostos antioxidantes. A espécie de pimentas Capsicum chinense, originária do Brasil apresenta mais de 40 variedades, sendo que muitas ainda são desconhecidas quanto as suas potencialidades. Neste trabalho foram caracterizados quanto à atividade antioxidante e ao teor de compostos fenólicos, cinco genótipos de pimenta C. chinense do Banco Ativo de Germoplasma da Embrapa Amazônia Oriental, visando identificar as variedades promissoras para serem utilizadas em futuros programas de melhoramento genético. A atividade antioxidante foi determinada através dos ensaios de DPPH e ABTS e os compostos fenólicos através do reagente de Follin Ciocalteau. Em relação ao teor de compostos fenólicos a variedade (PCL-02) destacou-se das demais com 12710 mgEAG/100g de pimenta. Houve diferença significativa ao nível de 5% nos resultados das três análises para as cinco variedades de pimenta analisada, demonstrando que a intensidade desta ação antioxidante é diferenciada em cada uma das variedades
Amine-Gold Linked Single-Molecule Junctions: Experiment and Theory
The measured conductance distribution for single molecule benzenediamine-gold
junctions, based on 59,000 individual conductance traces recorded while
breaking a gold point contact in solution, has a clear peak at 0.0064 G
with a width of 40%. Conductance calculations based on density functional
theory (DFT) for 15 distinct junction geometries show a similar spread.
Differences in local structure have a limited influence on conductance because
the amine-Au bonding motif is well-defined and flexible. The average calculated
conductance (0.046 G) is seven times larger than experiment, suggesting
the importance of many-electron corrections beyond DFT
Acquisition Correction and Reconstruction for a Clinical SPECT/MRI Insert
The development of the first clinical simultaneous Single Photon Emission Computed Tomography (SPECT) and Magnetic Resonance Imaging (MRI) system was carried out within the INSERT project. The INSERT scanner was constructed under the initial project, but its performance was not fully evaluated; here we have reconstructed the first images on the SPECT system. Calibration and acquisition protocols were developed and used to establish the clinical feasibility of the system. The image reconstruction procedures were implemented on the first phantom images in order to assess the system's imaging capabilities. This study solved issues involving incomplete data sets and pixel failure in the prototype detector system. The final images determined a measure of trans-axial image resolution, giving average values of 9.14 mm and 6.75 mm in the radial and tangential directions respectively. The work carried out on the complete system produced several clinical phantom images which utilized the capabilities of both SPECT and MRI
Pervasive and dynamic protein binding sites of the mRNA transcriptome in Saccharomyces cerevisiae
Abstract
Background
Protein-RNA interactions are integral components of nearly every aspect of biology, including regulation of gene expression, assembly of cellular architectures, and pathogenesis of human diseases. However, studies in the past few decades have only uncovered a small fraction of the vast landscape of the protein-RNA interactome in any organism, and even less is known about the dynamics of protein-RNA interactions under changing developmental and environmental conditions.
Results
Here, we describe the gPAR-CLIP (global photoactivatable-ribonucleoside-enhanced crosslinking and immunopurification) approach for capturing regions of the untranslated, polyadenylated transcriptome bound by RNA-binding proteins (RBPs) in budding yeast. We report over 13,000 RBP crosslinking sites in untranslated regions (UTRs) covering 72% of protein-coding transcripts encoded in the genome, confirming 3' UTRs as major sites for RBP interaction. Comparative genomic analyses reveal that RBP crosslinking sites are highly conserved, and RNA folding predictions indicate that secondary structural elements are constrained by protein binding and may serve as generalizable modes of RNA recognition. Finally, 38% of 3' UTR crosslinking sites show changes in RBP occupancy upon glucose or nitrogen deprivation, with major impacts on metabolic pathways as well as mitochondrial and ribosomal gene expression.
Conclusions
Our study offers an unprecedented view of the pervasiveness and dynamics of protein-RNA interactions in vivo.http://deepblue.lib.umich.edu/bitstream/2027.42/112318/1/13059_2012_Article_3050.pd
Integrated mode-locked lasers in a CMOS-compatible silicon photonic platform
CLEO: Science and Innovations 2015
San Jose, California United States
10–15 May 2015
ISBN: 978-1-55752-968-8
From the session:
Silicon Photonic Systems (SM2I)The final version is available from the publisher via the DOI in this record.Integrated components necessary for a mode-locked laser are demonstrated on a platform that allows for monolithic integration with active silicon photonics and CMOS circuitry. CW lasing and Q-switched mode-locking are observed in the full structures.This work was supported under the DARPA E-PHI project, grant no. HR0011-12-2-0007
zCOSMOS 20k: Satellite galaxies are the main drivers of environmental effects in the galaxy population at least to z~0.7
We explore the role of environment in the evolution of galaxies over
0.1<z<0.7 using the final zCOSMOS-bright data set. Using the red fraction of
galaxies as a proxy for the quenched population, we find that the fraction of
red galaxies increases with the environmental overdensity and with the stellar
mass, consistent with previous works. As at lower redshift, the red fraction
appears to be separable in mass and environment, suggesting the action of two
processes: mass and environmental quenching. The parameters describing these
appear to be essentially the same at z~0.7 as locally. We explore the relation
between red fraction, mass and environment also for the central and satellite
galaxies separately, paying close attention to the effects of impurities in the
central-satellite classification and using carefully constructed samples
matched in stellar mass. There is little evidence for a dependence of the red
fraction of centrals on overdensity. Satellites are consistently redder at all
overdensities, and the satellite quenching efficiency increases with
overdensity at 0.1<z<0.4. This is less marked at higher redshift, but both are
nevertheless consistent with the equivalent local measurements. At a given
stellar mass, the fraction of galaxies that are satellites also increases with
the overdensity. At a given overdensity and mass, the obtained relation between
the environmental quenching and the satellite fraction agrees well with the
satellite quenching efficiency, demonstrating that the environmental quenching
in the overall population is consistent with being entirely produced through
the satellite quenching process at least up to z=0.7. However, despite the
unprecedented size of our high redshift samples, the associated statistical
uncertainties are still significant and our statements should be understood as
approximations to physical reality, rather than physically exact formulae.Comment: 22 pages, 19 figures, submitted to MNRA
The VIMOS Public Extragalactic Redshift Survey (VIPERS). Exploring the dependence of the three-point correlation function on stellar mass and luminosity at 0.5<z<1.1
The three-point correlation function (3PCF) is a powerful probe to
investigate the clustering of matter in the Universe in a complementary way
with respect to lower-order statistics, providing additional information with
respect to the two-point correlation function and allowing us to shed light on
biasing, nonlinear processes, and deviations from Gaussian statistics. In this
paper, we analyse the first data release of the VIMOS Public Extragalactic
Redshift Survey (VIPERS), determining the dependence of the three-point
correlation function on luminosity and stellar mass at . We
exploit the VIPERS Public Data Release 1, consisting of more than 50,000
galaxies with B-band magnitudes in the range and stellar masses in the range
. We measure both the
connected 3PCF and the reduced 3PCF in redshift space, probing different
configurations and scales, in the range [Mpc/h]. We find a
significant dependence of the reduced 3PCF on scales and triangle shapes, with
stronger anisotropy at larger scales ( Mpc/h) and an almost flat trend
at smaller scales, Mpc/h. Massive and luminous galaxies present a
larger connected 3PCF, while the reduced 3PCF is remarkably insensitive to
magnitude and stellar masses in the range we explored. These trends, already
observed at low redshifts, are confirmed for the first time to be still valid
up to , providing support to the hierarchical scenario for which massive
and bright systems are expected to be more clustered. The possibility of using
the measured 3PCF to provide independent constraints on the linear galaxy bias
has also been explored, showing promising results in agreement with other
probes.Comment: 12 pages, 11 figures, 2 tables, accepted for publication in A&
The dependence of Galactic outflows on the properties and orientation of zCOSMOS galaxies at z ~ 1
We present an analysis of cool outflowing gas around galaxies, traced by MgII
absorption lines in the co-added spectra of a sample of 486 zCOSMOS galaxies at
1 < z < 1.5. These galaxies span a range of stellar masses (9.45<
log[M*/Msun]<10.7) and star formation rates (0.14 < log [SFR/Msun/yr] < 2.35).
We identify the cool outflowing component in the MgII absorption and find that
the equivalent width of the outflowing component increases with stellar mass.
The outflow equivalent width also increases steadily with the increasing star
formation rate of the galaxies. At similar stellar masses the blue galaxies
exhibit a significantly higher outflow equivalent width as compared to red
galaxies. The outflow equivalent width shows strong effect with star formation
surface density ({\Sigma}SFR) of the sample. For the disk galaxies, the outflow
equivalent width is higher for the face-on systems as compared to the edge-on
ones, indicating that for the disk galaxies, the outflowing gas is primarily
bipolar in geometry. Galaxies typically exhibit outflow velocities ranging from
-200 km/s to -300 km/s and on average the face-on galaxies exhibit higher
outflow velocity as compared to the edge-on ones. Galaxies with irregular
morphologies exhibit outflow equivalent width as well as outflow velocities
comparable to face on disk galaxies. These galaxies exhibit minimum mass
outflow rates > 5-7 Msun/yr and a mass loading factor ({\eta} = dMout/dt /SFR)
comparable to the star formation rates of the galaxies.Comment: 12 pages, 14 figures, ApJ submitte
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