606 research outputs found
The first confirmation of V-type asteroids among the Mars crosser population
The Mars crossing region constitutes a path to deliver asteroids from the
Inner Main Belt to the Earth crossing space. While both the Inner Main Belt and
the population of Earth crossing asteroids contains a significant fraction of
asteroids belonging to the V taxonomic class, only two of such V-type asteroids
has been detected in the Mars crossing region up to now. In this work, we
searched for asteroids belonging to the V class among the population of Mars
crossing asteroids, in order to support alternative paths to the delivery of
this bodies into the Earth crossing region. We selected 18 candidate V-type
asteroids in the Mars crossing region using observations contained in the Sloan
Digital Sky Survey Moving Objects Catalog. Then, we observed 4 of these
candidates to take their visible spectra using the Southern Astrophysical
Research Telescope (SOAR). We also performed the numerical simulation of the
orbital evolution of the observed asteroids. We confirmed that 3 of the
observed asteroids belong to the V class, and one of these may follow a path
that drives it to an Earth collision in some tens of million years
Essential role of STAT5a in DCIS formation and invasion following estrogen treatment
Ductal carcinoma in situ (DCIS) is one of the earliest stages of breast cancer (BCa). The mechanisms by which DCIS lesions progress to an invasive state while others remain indolent are yet to be fully characterized and both diagnosis and treatment of this pre-invasive disease could benefit from better understanding the pathways involved. While a decreased expression of Caveolin-1 (Cav-1) in the tumor microenvironment of patients with DCIS breast cancer was linked to progression to invasive breast cancer (IBC), the downstream effector(s) contributing to this process remain elusive. The current report shows elevated expression of Signal Transducer and Activator of Transcription 5a (STAT5a) within the DCIS-like lesions in Cav-1 KO mice following estrogen treatment and inhibition of STAT5a expression prevented the formation of these mammary lesions. In addition, STAT5a overexpression in a human DCIS cell line (MCF10DCIS.com) promoted their invasion, a process accelerated by estrogen treatment and associated with increased levels of the matrix metalloproteinase-9 (MMP-9) precursor. In sum, our results demonstrate a novel regulatory axis (Cav-1♦STAT5a♦MMP-9) in DCIS that is fully activated by the presence of estrogen. Our studies suggest to further study phosphorylated STAT5a (Y694) as a potential biomarker to guide and predict outcome of DCIS patient population
Quantum walks of correlated photon pairs in two-dimensional waveguide arrays
We demonstrate quantum walks of correlated photons in a 2D network of
directly laser written waveguides coupled in a 'swiss cross' arrangement. The
correlated detection events show high-visibility quantum interference and
unique composite behaviour: strong correlation and independence of the quantum
walkers, between and within the planes of the cross. Violations of a
classically defined inequality, for photons injected in the same plane and in
orthogonal planes, reveal non-classical behaviour in a non-planar structure.Comment: 5 pages, 5 figure
Risk factors and cardio-metabolic outcomes associated with metabolic-associated fatty liver disease in childhood
Background: Non-Alcoholic Fatty Liver Disease (NAFLD) is defined as increased liver fat percentage, and is the most common chronic liver disease in children. Rather than NAFLD, Metabolic-Associated Fatty Liver Disease (MAFLD), defined as increased liver fat with presence of adverse cardio-metabolic measures, might have more clinical relevance in children. We assessed the prevalence, risk-factors and cardio-metabolic outcomes of MAFLD at school-age. Methods: This cross-sectional analysis was embedded in an ongoing population-based prospective cohort study started in 2001, in the Netherlands. In 1910 children of 10 years, we measured liver fat fraction by magnetic resonance imaging (MRI), body mass index (BMI), blood pressure, and lipids, insulin, and glucose concentrations. Childhood lifestyle factors were obtained through questionnaires. MAFLD was defined as ≥2% liver fat in addition to excess adiposity (BMI or visceral adiposity), presence of metabolic risk (blood pressure, triglycerides and HDL-concentrations) or prediabetes (glucose). Findings: Of all children, 49.6% had ≥2% liver fat, and 25.2% fulfilled the criteria of MAFLD. Only non-European descent was associated with increased odds of MAFLD at nominal significance (Odds Ratio 1.38, 95% Confidence Interval 1.04, 1.82). Compared to children with <2% liver fat, those with MAFLD had increased odds of cardio-metabolic-risk-factor clustering (Odds Ratio 7.65, 95% Confidence Interval 5.04, 11.62). Interpretation: In this study, no NAFLD-associated childhood risk factors were associated with increased odds of childhood MAFLD, yet the findings suggest that ethnicity could be, despite mostly explained by socio-economic factors. Use of MAFLD criteria, rather than NAFLD, may identify children at risk for impaired cardio-metabolic health. Funding: Erasmus University MC, the Netherlands Organisation for Health Research and Development, the Ministry of Health, Welfare, and Sport, and the European Research Council.</p
MARVEL Analysis of the Measured High-Resolution Rovibronic Spectra of 90Zr16O
Zirconium oxide(ZrO) is an important astrophysical molecule that defines the
S-star classification class for cool giant stars. Accurate, empirical
rovibronic energy levels, with associated labels and uncertainties, are
reported for 9 low-lying electronic states of the diatomic 90Zr16O molecule.
These 8088 empirical energy levels are determined using the Marvel (Measured
Active Rotational-Vibrational Energy Levels) algorithm with 23 317 input
assigned transition frequencies, 22 549 of which were validated. A
temperature-dependent partition function is presented alongside updated
spectroscopic constants for the 9 low-lying electronic states
The Phenotypic Effects of Royal Jelly on Wild-Type \u3cem\u3eD. melanogaster\u3c/em\u3e Are Strain-Specific
The role for royal jelly (RJ) in promoting caste differentiation of honeybee larvae into queens rather than workers is well characterized. A recent study demonstrated that this poorly understood complex nutrition drives strikingly similar phenotypic effects in Drosophila melanogaster, such as increased body size and reduced developmental time, making possible the use of D. melanogaster as a model system for the genetic analysis of the cellular mechanisms underlying RJ and caste differentiation. We demonstrate here that RJ increases the body size of some wild-type strains of D. melanogaster but not others, and report significant delays in developmental time in all flies reared on RJ. These findings suggest that cryptic genetic variation may be a factor in the D. melanogaster response to RJ, and should be considered when attempting to elucidate response mechanisms to environmental changes in non-honeybee species
New Constraints on the Evolution of the Inner Northern Apennines by K-Ar Dating of Late Miocene-Early Pliocene Compression on the Island of Elba, Italy
The Northern Apennines (NA) orogenic wedge formed during Oligocene-Miocene convergence and westward subduction of Adria beneath the European Plate. Extension ensued in the Mid-Late Miocene in response to Adria roll-back, causing opening of the back-arc Northern Tyrrhenian Sea. Whether extension continues uninterrupted since the Mid-Late Miocene or it was punctuated by short-lived compressional events, remains, however, uncertain. We used the K-Ar method to date a set of brittle-ductile and brittle deformation zones from the Island of Elba to contribute to this debate. We dated the low-angle Zuccale Fault (ZF), the Capo Norsi-Monte Arco Thrust (CN-MAT), and the Calanchiole Shear Zone (CSZ). The CN-MAT and CSZ are moderately west dipping, top-to-the-east thrusts in the immediate footwall of the ZF. The CSZ slipped 6.14 ± 0.64 Ma (<0.1 μm fraction) and the CN-MAT 4.90 ± 0.27 Ma ago (<0.4 μm fraction). The ZF, although cutting the two other faults, yielded an older age of 7.58 ± 0.11 Ma (<0.1 μm fraction). The ZF gouge, however, contains an illitic detrital contaminant from the Paleozoic age flysch deformed in its hanging wall and the age thus is a maximum faulting age. Removal of ~1% of a 300-Ma-old contaminant brings the ZF faulting age to <4.90 Ma. Our results provide the first direct dating of brittle deformation in the Apennines, constraining Late Miocene-Early Pliocene regional compression. They call for a refinement of current NA geodynamic models in the framework of the Northern Tyrrhenian Sea extension
On the experimental verification of quantum complexity in linear optics
The first quantum technologies to solve computational problems that are
beyond the capabilities of classical computers are likely to be devices that
exploit characteristics inherent to a particular physical system, to tackle a
bespoke problem suited to those characteristics. Evidence implies that the
detection of ensembles of photons, which have propagated through a linear
optical circuit, is equivalent to sampling from a probability distribution that
is intractable to classical simulation. However, it is probable that the
complexity of this type of sampling problem means that its solution is
classically unverifiable within a feasible number of trials, and the task of
establishing correct operation becomes one of gathering sufficiently convincing
circumstantial evidence. Here, we develop scalable methods to experimentally
establish correct operation for this class of sampling algorithm, which we
implement with two different types of optical circuits for 3, 4, and 5 photons,
on Hilbert spaces of up to 50,000 dimensions. With only a small number of
trials, we establish a confidence >99% that we are not sampling from a uniform
distribution or a classical distribution, and we demonstrate a unitary specific
witness that functions robustly for small amounts of data. Like the algorithmic
operations they endorse, our methods exploit the characteristics native to the
quantum system in question. Here we observe and make an application of a
"bosonic clouding" phenomenon, interesting in its own right, where photons are
found in local groups of modes superposed across two locations. Our broad
approach is likely to be practical for all architectures for quantum
technologies where formal verification methods for quantum algorithms are
either intractable or unknown.Comment: Comments welcom
Selective Inhibitors of the JMJD2 Histone Demethylases: Combined Nondenaturing Mass Spectrometric Screening and Crystallographic Approachesâ€
Ferrous ion and 2-oxoglutarate (2OG) oxygenases catalyze the demethylation of N(epsilon)-methylated lysine residues in histones. Here we report studies on the inhibition of the JMJD2 subfamily of histone demethylases, employing binding analyses by nondenaturing mass spectrometry (MS), dynamic combinatorial chemistry coupled to MS, turnover assays, and crystallography. The results of initial binding and inhibition assays directed the production and analysis of a set of N-oxalyl-d-tyrosine derivatives to explore the extent of a subpocket at the JMJD2 active site. Some of the inhibitors were shown to be selective for JMJD2 over the hypoxia-inducible factor prolyl hydroxylase PHD2. A crystal structure of JMJD2A in complex with one of the potent inhibitors was obtained; modeling other inhibitors based on this structure predicts interactions that enable improved inhibition for some compounds
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