912 research outputs found
Modulation of the CD8+-T-cell response by CD4+ CD25+ regulatory T cells in patients with Hepatitis B virus infection
CD4+ CD25+ regulatory T cells have been shown to maintain peripheral tolerance against self and foreign
antigens. In this study we analyzed the effect of circulating CD4+ CD25+ T cells on CD8+-T-cell responses of
patients with chronic and resolved hepatitis B virus (HBV) infection. We demonstrated that circulating CD4+
CD25+ T cells modulate the function and expansion of HBV-specific CD8+ cells ex vivo in all patients,
regardless of whether they have chronic or resolved HBV infection. The possible role of CD4+ CD25+ T cells
in the pathogenesis of chronic HBV infection is not supported by these data. However, these results might have
implications for optimizing future immunotherapeutic approaches to HBV treatment
Evaluation of telomerase activity in nasal polyps
Background: The objective of this study was to assess if nasal polyps express telomerase activity and whether a difference could be found between the polyp and the surrounding mucosa of the middle meatus and between different portions of the polyp itself.
Methods: Nine patients affected by nasal polyposis were included in this study; four of these patients had recurring polyposis. Telomerase activity was measured by telomeric repeat amplification protocol assay. In six patients, the telomeric repeat amplification protocol assay was performed on the polyp and on the mucosa from the ipsilateral middle meatus. In a polyp, we were able to investigate telomerase activity of its different portions, corresponding to pedicle and fundus.
Results: Telomerase activity observed in nasal polyps was higher than that observed in samples from the ipsilateral middle meatus mucosa. High or intermediate telomerase activity was found to be related to predominant recurring polyposis.
Conclusions: Therefore, it could be postulated that telomerase activity could be related with the tendency of polyps to recur
Parity-dependent Kondo effect in ultrasmall metallic grains
We study the Kondo effect in an ultrasmall metallic grain, i.e. small enough
to have a discrete energy-level spectrum, by calculating the susceptibility chi
of the magnetic impurity. Our quantum Monte Carlo simulations, and analytic
solution of a simple model, show that the behavior changes dramatically
depending on whether the number of electrons in the grain is even or odd. We
suggest that the measurements of chi provide an effective experimental way of
probing the grain's number parity.Comment: 7 pages, 5 figures, accepted for publication on Europhysics Letter
Análisis tectonoestratigráfico del Grupo Puesto Viejo (San Rafael, Argentina): Evolución de un rift continental Triásico
La cuenca triásica que alberga al Grupo Puesto Viejo se localiza en el Bloque San Rafael, al oeste de las principales acumulaciones de esa edad del ámbito cuyano. Este depocentro elongado con geometría de graben limitado por fallas con dirección NNO-SSE constituye una subcuenca de carácter extensional, que puede ser caracterizado como un rift continental. El relleno del rift, de hasta 1000 metros de espesor, se acomoda a ese contexto geodinámico, fuertemente condicionado por la estructura y el magmatismo. El Grupo Puesto Viejo se depositó en depresiones estructurales que ponen en continuidad lateral unidades temporalmente sucesivas pero sin registro vertical continuo completo. El relleno puede ser dividido en 5 unidades de acumulación en función de la dominancia de elementos arquitectura- les y asociaciones de facies: (1) depósitos de flujos de detritos, (2) depósitos de relleno de canal, (3) depósitos de planicie de inundación, (4) depósitos piroclásticos, y (5) intrusivos y efusiones volcánicas. La distribución vertical y temporal de estas unidades de acumulación permitió definir para el Grupo Puesto Viejo un arreglo general aluvial con desarrollo de sistemas fluviales entrelazados a meandriformes de baja y de alta sinuosidad, que evolucionaron de forma local con poco transporte del material sedimentario, intercalados con productos de un magmatismo bimodal en la forma de mantos de ignimbritas riolíticas, lavas andesíticas e intrusivos someros andesíticos/basálticos. La evolución tectonoestratográfica del Grupo Puesto Viejo ocurrió siguiendo una alternancia sucesiva de episodios: 1) subsidencia mecánica; 2) quietud tectónica con desarrollo de sistemas aluviales y fluviales; 3) actividad volcánica, con variaciones en la duración y velocidad de los mismos. El Grupo Puesto Viejo se desarrolló dentro del marco geocronológico general de la extensión triásica del oeste de la Argentina y en particular de la Cuenca Cuyana, y sus etapas de rift evolucionaron durante el Triásico Medio, condicionadas por su posición de borde de cuenca, periférica al eje de extensión principal
Density anomaly in a competing interactions lattice gas model
We study a very simple model of a short-range attraction and an outer shell
repulsion as a test system for demixing phase transition and density anomaly.
The phase-diagram is obtained by applying mean field analysis and Monte Carlo
simulations to a two dimensional lattice gas with nearest-neighbors attraction
and next-nearest-neighbors repulsion (the outer shell). Two liquid phases and
density anomaly are found.
The coexistence line between these two liquid phases meets a critical line
between the fluid and the low density liquid at a tricritical point. The line
of maximum density emerges in the vicinity of the tricritical point, close to
the demixing transition
Extended Abstracts
ABSTRACT A mathematical reprocessing of old seismic lines let ta know the Crustal Structure down to 35 km depth. Deep seismic discontinuities were interpreted as the top of the lower Crust and the ancestral master-shear which controlled the rift basin geometry during the late Cretaceous -early Jurassic. In addition, important inversion events were recognized by seismic stratigraphie analysis of the basin, and dated as Pliensbachian -Torcian and Bathonian -Callovian
Nanoscale Dynamics of Phase Flipping in Water near its Hypothesized Liquid-Liquid Critical Point
Achieving a coherent understanding of the many thermodynamic and dynamic
anomalies of water is among the most important unsolved puzzles in physics,
chemistry, and biology. One hypothesized explanation imagines the existence of
a line of first order phase transitions separating two liquid phases and
terminating at a novel "liquid-liquid" critical point in a region of low
temperature () and high pressure (). Here we analyze a common model of water, the ST2 model, and find
that the entire system flips between liquid states of high and low density.
Further, we find that in the critical region crystallites melt on a time scale
of nanoseconds. We perform a finite-size scaling analysis that accurately
locates both the liquid-liquid coexistence line and its associated
liquid-liquid critical point.Comment: 22 pages, 5 figure
Potential energy landscape-based extended van der Waals equation
The inherent structures ({\it IS}) are the local minima of the potential
energy surface or landscape, , of an {\it N} atom system.
Stillinger has given an exact {\it IS} formulation of thermodynamics. Here the
implications for the equation of state are investigated. It is shown that the
van der Waals ({\it vdW}) equation, with density-dependent and
coefficients, holds on the high-temperature plateau of the averaged {\it IS}
energy. However, an additional ``landscape'' contribution to the pressure is
found at lower . The resulting extended {\it vdW} equation, unlike the
original, is capable of yielding a water-like density anomaly, flat isotherms
in the coexistence region {\it vs} {\it vdW} loops, and several other desirable
features. The plateau energy, the width of the distribution of {\it IS}, and
the ``top of the landscape'' temperature are simulated over a broad reduced
density range, , in the Lennard-Jones fluid. Fits to the
data yield an explicit equation of state, which is argued to be useful at high
density; it nevertheless reproduces the known values of and at the
critical point
A Self-Attention Deep Neural Network Regressor for real time blood glucose estimation in paediatric population using physiological signals
With the advent of modern digital technology, the physiological signals (such as electrocardiogram) are being acquired from portable wearable devices which are being used for non-invasive chronic disease management (such as Type 1 Diabetes). The diabetes management requires real-time assessment of blood glucose which is cumbersome for paediatric population due to clinical complexity and invasiveness. Therefore, real-time non-invasive blood glucose estimation is now pivotal for effective diabetes management. In this paper, we propose a Self-Attention Deep Neural Network Regressor for real-time non-invasive blood glucose estimation for paediatric population based on automatically extracted beat morphology. The first stage performs Morphological Extractor based on Self-Attention based Long Short-Term Memory driven by Convolutional Neural Network for highlighting local features based on temporal context. The second stage is based on Morphological Regressor driven by multilayer perceptron with dropout and batch normalization to avoid overfitting. We performed feature selection via logit model followed by Spearman's correlation among features to avoid feature redundancy. We trained as tested our model on publicly available MIT/BIH-Physionet databases and physiological signals acquired from a T1D paediatric population. We performed our evaluation via Clarke's Grid error to analyse estimation accuracy on range of blood values under different glycaemic conditions. The results show that our tool outperformed existing regression models with 89% accuracy under clinically acceptable range. The proposed model based on beat morphology significantly outperformed models based on HRV features
Percolation transition and the onset of non exponential relaxation in fully frustrated models
We numerically study the dynamical properties of fully frustrated models in 2
and 3 dimensions. The results obtained support the hypothesis that the
percolation transition of the Kasteleyn-Fortuin clusters corresponds to the
onset of stretched exponential autocorrelation functions in systems without
disorder. This dynamical behavior may be due to the ``large scale'' effects of
frustration, present below the percolation threshold. Moreover these results
are consistent with the picture suggested by Campbell et al. in space of
configurations.Comment: 8 pages, 11 figures, revised versio
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