Spin filtering and entanglement detection due to spin-orbit interaction in carbon nanotube cross-junctions

We demonstrate that due to their spin-orbit interaction carbon nanotube cross-junctions have attractive spin projective properties for transport. First, we show that the junction can be used as a versatile spin filter as a function of a backgate and a static external magnetic field. Switching between opposite spin filter directions can be achieved by small changes of the backgate potential, and a full polarization is generically obtained in an energy range close to the Dirac points. Second, we discuss how the spin filtering properties affect the noise correlators of entangled electron pairs, which allows us to obtain signatures of the type of entanglement that are different from the signatures in conventional semiconductor cross-junctions.Comment: 14 pages, 8 figures. Final versio

Role of matrix metalloproteinase in the aneurismatic aortic disease

The aorta is involved in a large variety of diseases and the atherosclerotic aneurysms represent the most common type of these. Recent reports have attempted to clarify the mechanisms, that cause the formation and the progression of the atherosclerotic aneurysms, caused not only by the atherosclerosis. One of the features of this disease is the extensive proteolytic destruction of structural matrix proteins in the aortic wall realized by the matrix metalloproteinases. The atherosclerotic aneurysm can be considered a disease caused by an imbalance between connective tissue destruction and its repair. Knowledge of the role played by matrix metalloproteinases in the formation process of the aneurysms has made the inhibition of these proteins a logical therapeutic strategy. Once completed the aneurysm treatment, surgical or endovascular, the endothelial damage must disappear; the persistence of this damage, after endovascular procedure, is the cause of the formation of the endoleaks. The preoperative matrix metalloproteinases plasmatic levels are related to the aneurysm diameter and after endovascular treatment these values come back normal, except in the case of presence of an endoleak, that don't make possible the reduction of these values. In spite of that, obscure points still remain, above all about the dosage of these proteins and their inhibition through drugs with clear metalloproteinases- inhibiting properties. The aim of this study is to clarify further on the mechanisms of the formation of the aneurysms with particular care to the matrix metalloproteinases, their dosage and their drug inhibition

A Bayesian generative neural network framework for epidemic inference problems

The reconstruction of missing information in epidemic spreading on contact networks can be essential in the prevention and containment strategies. The identification and warning of infectious but asymptomatic individuals (i.e., contact tracing), the well-known patient-zero problem, or the inference of the infectivity values in structured populations are examples of significant epidemic inference problems. As the number of possible epidemic cascades grows exponentially with the number of individuals involved and only an almost negligible subset of them is compatible with the observations (e.g., medical tests), epidemic inference in contact networks poses incredible computational challenges. We present a new generative neural networks framework that learns to generate the most probable infection cascades compatible with observations. The proposed method achieves better (in some cases, significantly better) or comparable results with existing methods in all problems considered both in synthetic and real contact networks. Given its generality, clear Bayesian and variational nature, the presented framework paves the way to solve fundamental inference epidemic problems with high precision in small and medium-sized real case scenarios such as the spread of infections in workplaces and hospitals

Small-Coupling Dynamic Cavity: a Bayesian mean-field framework for epidemic inference

A novel generalized mean field approximation, called the Small-Coupling Dynamic Cavity (SCDC) method, for Bayesian epidemic inference and risk assessment is presented. The method is developed within a fully Bayesian framework and accounts for non-causal effects generated by the presence of observations. It is based on a graphical model representation of the epidemic stochastic process and utilizes dynamic cavity equations to derive a set of self-consistent equations for probability marginals defined on the edges of the contact graph. By performing a small-coupling expansion, a pair of time-dependent cavity messages is obtained, which capture the probability of individual infection and the conditioning power of observations. In its efficient formulation, the computational cost per iteration of the SCDC algorithm is linear in the duration of the epidemic dynamics and in the number of contacts. The SCDC method is derived for the Susceptible-Infected (SI) model and straightforwardly applicable to other Markovian epidemic processes, including recurrent ones. It exhibits high accuracy in assessing individual risk on par with Belief Propagation techniques and outperforming heuristic methods based on individual-based mean-field approximations. Although convergence issues may arise due to long-range correlations in contact graphs, the estimated marginal probabilities remain sufficiently accurate for reliable risk estimation. Future work includes extending the method to non-Markovian recurrent epidemic models and investigating the role of second-order terms in the small coupling expansion of the observation-reweighted Dynamic Cavity equations.Comment: 29 pages, 7 figures (including appendices

Grafted Neural Precursors Integrate Into Mouse Striatum, Differentiate and Promote Recovery of Function Through Release of Erythropoietin in MPTP-Treated Mice.

Erythropoietin-releasing neural precursor cells (Er-NPCs) are a subclass of subventricular zone-derived neural progenitors, capable of surviving for 6 hr after death of donor. They present higher neural differentiation. Here, Er-NPCs were studied in animal model of Parkinson's disease. Dopaminergic degeneration was caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intraperitoneal administration in C57BL/6 mice. The loss of function was evaluated by specific behavioral tests. Er-NPCs (2.5 × 105) expressing the green fluorescent protein were administered by stereotaxic injection unilaterally in the left striatum. At the end of observational research period (2 weeks), most of the transplanted Er-NPCs were located in the striatum, while several had migrated ventrally and caudally from the injection site, up to ipsilateral and contralateral substantia nigra. Most of transplanted cells had differentiated into dopaminergic, cholinergic, or GABAergic neurons. Er-NPCs administration also promoted a rapid functional improvement that was already evident at the third day after cells administration. This was accompanied by enhanced survival of nigral neurons. These effects were likely promoted by Er-NPCs-released erythropoietin (EPO), since the injection of Er-NPCs in association with anti-EPO or anti-EPOR antibodies had completely neutralized the recovery of function. In addition, intrastriatal administration of recombinant EPO mimics the effects of Er-NPCs. We suggest that Er-NPCs, and cells with similar properties, may represent good candidates for cellular therapy in neurodegenerative disorders of this kind

Renal hemodynamic response to maximal vasodilating stimulus in healthy older subjects

Renal hemodynamic response to maximal vasodilating stimulus in healthy older subjects.BackgroundIt is still unclear whether age per se is associated with preservation of renal functional reserve, that is, of the increase in glomerular filtration rate (GFR) induced by appropriate vasodilating stimulus.MethodsTo gain insights into this issue, we evaluated the renal response to a maximal vasodilating stimulus, represented by the combined infusion of mixed amino acid solution (AA) and dopamine at renal dose (D), in 10 young subjects (median age of 30 years, range of 19 to 32) and in 11 subjects of older age (median age of 67 years, range of 65 to 76). Two further age-matched groups of young (N = 15) and older (N = 11) living kidney donors underwent renal needle biopsy immediately before nephrectomy to perform semiquantitative scoring (0 to 3) of arteriosclerosis in intrarenal arteries. All of the study subjects were nonsmokers with healthy status proven by extensive diagnostic evaluation excluding any risk factor of renal dysfunction.ResultsBasal renal plasma flow (RPF) and GFR were proportionally lower in older subjects (RPF, 361 ± 29 vs. 618 ± 34mL/min/1.73m2, P < 0.001; GFR, 79 ± 4 vs. 127 ± 5.8mL/min/1.73m2, P < 0.001). After AA + D, a significant increase of RPF and GFR was observed in both groups, but the older subjects exhibited a smaller percentage increment (RPF, 25.5 ± 4.8 vs. 42.4 ± 5.8, P < 0.05; GFR, 19.6 ± 5.7 vs. + 33.8 ± 6.4, P < 0.05). Furthermore, the maximal vasodilating stimulus was not able to restore renal hemodynamics in older subjects to the level measured in young controls at baseline. Renal vascular resistances were higher (P < 0.05) in the older subjects both at baseline (0.19 ± 0.02 vs. 0.09 ± 0.004mm Hg/mL/min) and after AA + D (0.14 ± 0.01 vs. 0.06 ± 0.004). Light microscopy examination detected the presence of a greater degree of arteriosclerosis at the level of interlobular and arcuate arteries (0.89 ± 0.15 vs. 0.45 ± 0.08) and interstitial fibrosis/tubular atrophy (1.18 ± 0.13 vs. 0.53 ± 0.13) in older than in young subjects.ConclusionsTherefore, aging has adverse effects on renal function despite the absence of any risk factor for renal disease, including chronic smoking: (1) GFR and RPF are lower, and (2) the renal response to maximal vasodilating stimulus is impaired. These aging-related alterations of renal hemodynamics are possibly due to organic lesions in renal vasculature

Descripción anatómica de la 3ª porción del nervio facial

El presente trabajo tiene como objetivo principal la descripción de la 3era Porción del Nervio Facial, con especial interés en su disposición espacial y relaciones intrapetrosas. El motivo del presente trabajo es explicar las razones por las cuales este segmento es el más afectado en forma iatrogénica en las cirugías de oído medio.Facultad de Ciencias Médica

Descripción anatómica de la 3ª porción del nervio facial

El presente trabajo tiene como objetivo principal la descripción de la 3era Porción del Nervio Facial, con especial interés en su disposición espacial y relaciones intrapetrosas. El motivo del presente trabajo es explicar las razones por las cuales este segmento es el más afectado en forma iatrogénica en las cirugías de oído medio.Facultad de Ciencias Médica

Descripción anatómica de la 3ª porción del nervio facial

El presente trabajo tiene como objetivo principal la descripción de la 3era Porción del Nervio Facial, con especial interés en su disposición espacial y relaciones intrapetrosas. El motivo del presente trabajo es explicar las razones por las cuales este segmento es el más afectado en forma iatrogénica en las cirugías de oído medio.Facultad de Ciencias Médica

Epidemic mitigation by statistical inference from contact tracing data

Contact-tracing is an essential tool in order to mitigate the impact of pandemic such as the COVID-19. In order to achieve efficient and scalable contact-tracing in real time, digital devices can play an important role. While a lot of attention has been paid to analyzing the privacy and ethical risks of the associated mobile applications, so far much less research has been devoted to optimizing their performance and assessing their impact on the mitigation of the epidemic. We develop Bayesian inference methods to estimate the risk that an individual is infected. This inference is based on the list of his recent contacts and their own risk levels, as well as personal information such as results of tests or presence of syndromes. We propose to use probabilistic risk estimation in order to optimize testing and quarantining strategies for the control of an epidemic. Our results show that in some range of epidemic spreading (typically when the manual tracing of all contacts of infected people becomes practically impossible, but before the fraction of infected people reaches the scale where a lock-down becomes unavoidable), this inference of individuals at risk could be an efficient way to mitigate the epidemic. Our approaches translate into fully distributed algorithms that only require communication between individuals who have recently been in contact. Such communication may be encrypted and anonymized and thus compatible with privacy preserving standards. We conclude that probabilistic risk estimation is capable to enhance performance of digital contact tracing and should be considered in the currently developed mobile applications.Comment: 21 pages, 7 figure