1,043 research outputs found
Atrioventricular canal defect and genetic syndromes: the unifying role of sonic hedgehog
The atrioventricular canal defect (AVCD) is a congenital heart defect (CHD) frequently associated with extracardiac anomalies (75%). Previous observations from a personal series of patients with AVCD and "polydactyly syndromes" showed that the distinct morphology and combination of AVCD features in some of these syndromes is reminiscent of the cardiac phenotype found in heterotaxy, a malformation complex previously associated with functional cilia abnormalities and aberrant Hedgehog (Hh) signaling. Hh signaling coordinates multiple aspects of left-right lateralization and cardiovascular growth. Being active at the venous pole the secondary heart field (SHF) is essential for normal development of dorsal mesenchymal protrusion and AVCD formation and septation. Experimental data show that perturbations of different components of the Hh pathway can lead to developmental errors presenting with partially overlapping manifestations and AVCD as a common denominator. We review the potential role of Hh signaling in the pathogenesis of AVCD in different genetic disorders. AVCD can be viewed as part of a "developmental field," according to the concept that malformations can be due to defects in signal transduction cascades or pathways, as morphogenetic units which may be altered by Mendelian mutations, aneuploidies, and environmental causes
Erratum to: An Entropy Functional for Riemann-Cartan Space-Times
We correct the entropy functional constructed in Int. J. Theor. Phys. 51:362
(2012). The 'on-shell' functional one obtains from this correct functional
possesses a holographic structure without imposing any constraint on the
spin-angular momentum tensor of matter, in contrast to the conclusion made in
the above paper.Comment: 15 pages. These are the preprints of the original paper and its
erratum published in Int. J. Theor. Phy
Crossover between Equilibrium and Shear-controlled Dynamics in Sheared Liquids
We present a numerical simulation study of a simple monatomic Lennard-Jones
liquid under shear flow, as a function of both temperature and shear rate. By
investigating different observables we find that i) It exists a line in the
(temperature-shear) plane that sharply marks the boarder between an
``equilibrium'' and a ``shear-controlled'' region for both the dynamic and the
thermodynamic quantities; and ii) Along this line the structural relaxation
time, is proportional to the inverse shear rate, i.e. to the typical time-scale
introduced by the shear flow. Above the line the liquid dynamics is unaffected
by the shear flow, while below it both temperature and shear rate control the
particle motion.Comment: 14 pages, 5 figure
Gravitomagnetism and Relative Observer Clock Effects
The gravitomagnetic clock effect and the Sagnac effect for circularly
rotating orbits in stationary axisymmetric spacetimes are studied from a
relative observer point of view, clarifying their relationships and the roles
played by special observer families. In particular Semer\'ak's recent
characterization of extremely accelerated observers in terms of the two-clock
clock effect is shown to be complemented by a similarly special property of the
single-clock clock effect.Comment: 19 pages, LaTeX, IOP macros with package epsf and 1 eps figure, to
appear in Classical and Quantum Gravity, slight revisio
Deregulated expression of aurora kinases is not a prognostic biomarker in papillary thyroid cancer patients.
Abstract
A number of reports indicated that Aurora-A or Aurora-B overexpression represented a negative prognostic factor in several human malignancies. In thyroid cancer tissues a deregulated expression of Aurora kinases has been also demonstrated, butno information regarding its possible prognostic role in differentiated thyroid cancer is available. Here, weevaluated Aurora-A and Aurora-B mRNA expression and its prognostic relevance in a series of 87 papillary thyroid cancers (PTC), with a median follow-up of 63 months. The analysis of Aurora-A and Aurora-B mRNA levels in PTC tissues, compared to normal matched tissues, revealed that their expression was either up-or down-regulatedin the majority of cancer tissues. In particular, Aurora-A and Aurora-B mRNA levels were altered, respectively, in 55 (63.2%) and 79 (90.8%) out of the 87 PTC analyzed. A significant positive correlation between Aurora-A and Aurora-B mRNAswas observed (p=0.001). The expression of both Aurora genes was not affected by the BRAF(V600E) mutation. Univariate, multivariate and Kaplan-Mayer analyses documented the lack of association between Aurora-A or Aurora-B expression and clinicopathological parameterssuch as gender, age, tumor size, histology, TNM stage, lymph node metastasis and BRAF status as well asdisease recurrences or disease-free interval. Only Aurora-B mRNA was significantly higher in T(3-4) tissues, with respect to T(1-2) PTC tissues. The data reported here demonstrate that the expression of Aurora kinases is deregulated in the majority of PTC tissues, likely contributing to PTC progression. However, differently from other human solid cancers, detection of Aurora-A or Aurora-B mRNAs is not a prognostic biomarker inPTC patients
Low-grade gliomas in patients with Noonan syndrome: case-based review of the literature
Noonan syndrome (NS) is a congenital autosomic dominant condition characterized by a variable spectrum from a clinical and genetical point of view. Germline mutations in more than ten genes involved in RASâMAPK signal pathway have been demonstrated to cause the disease. An higher risk for leukemia and solid malignancies, including brain tumors, is related to NS. A review of the published literature concerning low grade gliomas (LGGs) in NS is presented. We described also a 13-year-old girl with NS associated with a recurrent mutation in PTPN11, who developed three different types of brain tumors, i.e., an optic pathway glioma, a glioneuronal neoplasm of the left temporal lobe and a cerebellar pilocytic astrocytoma. Molecular characterization of the glioneuronal tumor allowed to detect high levels of phosphorylated MTOR (pMTOR); therefore, a therapeutic approach based on an mTOR inhibitor (everolimus) was elected. The treatment was well tolerated and proved to be effective, leading to a stabilization of the tumor, which was surgical removed. The positive outcome of the present case suggests considering this approach for patients with RASopathies and brain tumors with hyperactivated MTOR signaling
Dynamics of supercooled liquids: density fluctuations and Mode Coupling Theory
We write equations of motion for density variables that are equivalent to
Newtons equations. We then propose a set of trial equations parameterised by
two unknown functions to describe the exact equations. These are chosen to best
fit the exact Newtonian equations. Following established ideas, we choose to
separate these trial functions into a set representing integrable motions of
density waves, and a set containing all effects of non-integrability. It
transpires that the static structure factor is fixed by this minimum condition
to be the solution of the Yvon-Born-Green (YBG) equation. The residual
interactions between density waves are explicitly isolated in their Newtonian
representation and expanded by choosing the dominant objects in the phase space
of the system, that can be represented by a dissipative term with memory and a
random noise. This provides a mapping between deterministic and stochastic
dynamics. Imposing the Fluctuation-Dissipation Theorem (FDT) allows us to
calculate the memory kernel. We write exactly the expression for it, following
two different routes, i.e. using explicitly Newtons equations, or instead,
their implicit form, that must be projected onto density pairs, as in the
development of the well-established Mode Coupling Theory (MCT). We compare
these two ways of proceeding, showing the necessity to enforce a new equation
of constraint for the two schemes to be consistent. Thus, while in the first
`Newtonian' representation a simple gaussian approximation for the random
process leads easily to the Mean Spherical Approximation (MSA) for the statics
and to MCT for the dynamics of the system, in the second case higher levels of
approximation are required to have a fully consistent theory
The GINGER Project and status of the ring-laser of LNGS
A ring-laser attached to the Earth measures the absolute angular velocity of the Earth summed
to the relativistic precessions, de Sitter and Lense-Thirring. GINGER (Gyroscopes IN GEneral
Relativity) is a project aiming at measuring the LenseThirring effect with a ground based detector;
it is based on an array of ring-lasers. Comparing the Earth angular velocity measured
by IERS and the measurement done with the GINGER array, the Lense-Thirring effect can be
evaluated. Compared to the existing space experiments, GINGER provides a local measurement,
not the averaged value and it is unnecessary to model the gravitational field. It is a proposal,
but it is not far from being a reality. In fact the GrossRing G of the Geodesy Observatory of
Wettzell has a sensitivity very close to the necessary one. G ofWettzell is part of the IERS system
which provides the measure of the Length Of the DAY (LOD); G provides information on the fast
component of LOD. In the last few years, a roadmap toward GINGER has been outlined. The
experiment G-GranSasso, financed by the INFN Commission II, is developing instrumentations
and tests along the roadmap of GINGER. In this short paper the main activities of G-GranSasso
and some results will be presented. The first results of GINGERino will be reported, GINGERino
is the large ring-laser installed inside LNGS and now in the commissioning phase. Ring-lasers
provide as well important informations for geophysics, in particular the rotational seismology,
which is an emerging field of science. GINGERino is one of the three experiments of common
interest between INFN and INGV
Water excess in different phenological stages of canola cultivars.
The objective of this study was to determine the stage of development with greater sensitivity to water excess and the period of time required to compromise the emergence and grain yield components of canola. The experiments were performed in a greenhouse at the Federal University of Santa Maria and at the Farroupilha Federal Institute, Campus of SĂŁo Vicente do Sul, RS during the 2015 agricultural year. The completely randomized experimental design was utilized to investigate phenological stages and periods of continuous water excess in the soil. Also, factors like percentage of emergence, emergence speed index, grain yield, number of siliques per plant, one hundred grains weight, dry matter of aerial part, silique length, number of grains per silique, and weight of 20 siliques were determined. The stages of rosette leaf formation and beginning of anthesis are the most sensitive to water excess in the soil. Water excess for 24 h is enough to reduce the emergence speed index. However, the percentage of emergence is not compromised by water excess up to 192 continuous hours. 24 h of water excess reduces the number of siliques per plant, dry matter of aerial part and grain yield of canola
InfluĂȘncia do preparo do solo na duração dos subperĂodos de desenvolvimento da canola em solos com excesso hĂdrico.
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