Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Context (language use). The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

Overexpression of the autophagic beclin-1 protein clears mutant ataxin-3 and alleviates Machado-Joseph disease.

Abstract: Machado–Joseph disease, also known as spinocerebellar ataxia type 3, is the most common of the dominantly inherited ataxias worldwide and is characterized by mutant ataxin-3 misfolding, intracellular accumulation of aggregates and neuronal degeneration. Here we investigated the implication of autophagy, the major pathway for organelle and protein turnover, in the accumulation of mutant ataxin-3 aggregates and neurodegeneration found in Machado–Joseph disease and we assessed whether specific stimulation of this pathway could mitigate the disease. Using tissue from patients with Machado–Joseph disease, transgenic mice and a lentiviral-based rat model, we found an abnormal expression of endogenous autophagic markers, accumulation of autophagosomes and decreased levels of beclin-1, a crucial protein in the early nucleation step of autophagy. Lentiviral vector-mediated overexpression of beclin-1 led to stimulation of autophagic flux, mutant ataxin-3 clearance and overall neuroprotective effects in neuronal cultures and in a lentiviral-based rat model of Machado–Joseph disease. These data demonstrate that autophagy is a key degradation pathway, with beclin-1 playing a significant role in alleviating Machado–Joseph disease pathogenesis. * Abbreviations : Atg : autophagic related protein DARPP-32 : dopamine-and-cyclic AMP-regulated phosphoprotein of 32 kDa p62 : sequestosome 1/p62 protein

Negative refraction and sub-wavelength focusing in the visible range using transparent metallo-dielectric stacks

Abstract: We numerically demonstrate negative refraction of the Poynting vector and sub-wavelength focusing in the visible part of the spectrum using a transparent multilayer, metallo-dielectric photonic band gap structure. Our results reveal that in the wavelength regime of interest evanescent waves are not transmitted by the structure, and that the main underlying physical mechanisms for sub-wavelength focusing are resonance tunneling, field localization, and propagation effects. These structures offer several advantages: tunability and high transmittance (50% or better) across the visible and near IR ranges; large object-image distances, with image planes located beyond the range where the evanescent waves have decayed. From a practical point of view, our findings point to a simpler way to fabricate a material that exhibits negative refraction and maintains high transparency across a broad wavelength range. Transparent metallo-dielectric stacks also provide an opportunity to expand the exploration of wave propagation phenomena in metals, both in the linear and nonlinear regimes.

Short-Term State Forecasting-Aided Method for Detection of Smart Grid General False Data Injection Attacks

Abstract: Successful detection of false data injection attacks (FDIAs) is essential for ensuring secure power grids operation and control. First, this paper extends the approximate dc model to a more general linear model that can handle both supervisory control and data acquisition and phasor measurement unit measurements. Then, a general FDIA based on this model is derived and the error tolerance of such attacks is discussed. To detect such attacks, a method based on short-term state forecasting considering temporal correlation is proposed. Furthermore, a statistics-based measurement consistency test method is presented to check the consistency between the forecasted measurements and the received measurements. This measurement consistency test is further integrated with ${\infty }$ -norm and ${L}_{{2}}$ -norm-based measurement residual analysis to construct the proposed detection metric. The proposed detector addresses the shortcoming of previous detectors in terms of handling critical measurements. Besides, the removal problem of attacked measurements, which may cause the system to become unobservable, is addressed effectively by the proposed method through forecasted measurements. Numerical tests on IEEE 14-bus and 118-bus test systems verify the effectiveness and performance of the proposed method.

Danger signals – damaged-self recognition across the tree of life

Abstract: Multicellular organisms suffer injury and serve as hosts for microorganisms. Therefore, they require mechanisms to detect injury and to distinguish the self from the non-self and the harmless non-self (microbial mutualists and commensals) from the detrimental non-self (pathogens). Danger signals are 'damage-associated molecular patterns' (DAMPs) that are released from the disrupted host tissue or exposed on stressed cells. Seemingly ubiquitous DAMPs are extracellular ATP or extracellular DNA, fragmented cell walls or extracellular matrices, and many other types of delocalized molecules and fragments of macromolecules that are released when pre-existing precursors come into contact with enzymes from which they are separated in the intact cell. Any kind of these DAMPs enable damaged-self recognition, inform the host on tissue disruption, initiate processes aimed at restoring homeostasis, such as sealing the wound, and prepare the adjacent tissues for the perception of invaders. In mammals, antigen-processing and -presenting cells such as dendritic cells mature to immunostimulatory cells after the perception of DAMPs, prime naive T-cells and elicit a specific adaptive T-/B-cell immune response. We discuss molecules that serve as DAMPs in multiple organisms and their perception by pattern recognition receptors (PRRs). Ca2+- fluxes, membrane depolarization, the liberation of reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) signalling cascades are the ubiquitous molecular mechanisms that act downstream of the PRRs in organisms across the tree of life. Damaged-self recognition contains both homologous and analogous elements and is likely to have evolved in all eukaryotic kingdoms, because all organisms found the same solutions for the same problem: damage must be recognized without depending on enemy-derived molecules and responses to the non-self must be directed specifically against detrimental invaders.