Intermediate Filament Aggregates Cause Mitochondrial Dysmotility and Increase Energy Demands in Giant Axonal Neuropathy

Intermediate filaments (IFs) are cytoskeletal polymers that extend from the nucleus to the cell membrane, giving cells their shape and form. Abnormal accumulation of IFs is involved in the pathogenesis of number neurodegenerative diseases, but none as clearly as giant axonal neuropathy (GAN), a ravaging disease caused by mutations inGAN,encoding gigaxonin.Patients display early and severe degeneration of the peripheral nervous system along with IF accumulation, but it has been difficult to linkGANmutations to any particular dysfunction, in part because GAN null mice have a very mild phenotype. We therefore established a robust dorsal root ganglion neuronal model that mirrors key cellular events underlying GAN. We demonstrate that gigaxonin is crucial for ubiquitin-proteasomal degradation of neuronal IF. Moreover, IF accumulation impairs mitochondrial motility and is associated with metabolic and oxidative stress. These results have implications for other neurological disorders whose pathology includes IF accumulation

Monocular Visual-Inertial SLAM-Based Collision Avoidance Strategy for Fail-Safe UAV Using Fuzzy Logic Controllers

In this paper, we developed a novel Cross-Entropy Optimization (CEO)-based Fuzzy Logic Controller (FLC) for Fail-Safe UAV to expand its collision avoidance capabilities in the GPS-denied environments using Monocular Visual-Inertial SLAM-based strategy. The function of this FLC aims to control the heading of Fail-Safe UAV to avoid the obstacle, e.g. wall, bridge, tree line et al, using its real-time and accurate localization information. In the Matlab Simulink-based training framework, the Scaling Factor (SF) is adjusted according to the collision avoidance task firstly, and then the Membership Function (MF) is tuned based on the optimized Scaling Factor to further improve the control performances. After obtained the optimal SF and MF, 64 % of rules has been reduced (from 125 rules to 45 rules), and a large number of real see-and-avoid tests with a quadcopter have done. The simulation and experiment results show that this new proposed FLC can precisely navigates the Fail-Safe UAV to avoid the obstacle, obtaining better performances compared to only SF optimization-based FLC. To our best knowledge, this is the first work to present the optimized FLC using Cross-Entropy method in both SF and MF optimization, and apply it in the UAV. © Springer Science+Business Media Dordrecht 2013.This work has been sponsored by the Spanish Science and Technology Ministry under the grant CICYT DPI2010-20751-C02-01, OMNIWORKS project (an experiment funded in the context of the ECHORD project (FP7-ICT-231143)) and the China Scholarship Council (CSC).Peer Reviewe

MAPEAMENTO 3D DE AMBIENTES INTERNOS USANDO DADOS RGB-D

ResumoNeste trabalho é introduzido um fluxo de mapeamento 3D de ambientes internos usando dados RGB-D. O método explora a integração de imagens RGB e valores de profundidade oriundos do dispositivo Kinect. Cinco etapas principais envolvidas no desenvolvimento do método proposto são discutidas. A primeira etapa trata da detecção de pontos no par de imagens RGB e o estabelecimento automático das correspondências. Na segunda etapa do método é proposto uma normalização das imagens RGB e IR para associar os pontos homólogos encontrados no par de imagens RGB e seus correspondentes na imagem de profundidade. Na terceira etapa as coordenadas XYZ de cada ponto são calculadas. Em seguida, são calculados os parâmetros de transformação entre os pares de nuvem de pontos 3D. Finalmente, é proposto um modelo linear para a análise da consistência global. Para avaliar a eficiência e potencialidade do método proposto foram realizados quatro experimentos em ambientes internos. Uma avaliação da acurácia relativa da trajetória do sensor mostrou erros no registro de pares de nuvens de pontos em torno de 3,0 c

Calcium signaling in Parkinson’s disease

Calcium (Ca2+) is an almost universal second messenger that regulates important activities of all eukaryotic cells. It is of critical importance to neurons, which have developed extensive and intricate pathways to couple the Ca2+ signal to their biochemical machinery. In particular, Ca2+ participates in the transmission of the depolarizing signal and contributes to synaptic activity. During aging and in neurodegenerative disease processes, the ability of neurons to maintain an adequate energy level can be compromised, thus impacting on Ca2+ homeostasis. In Parkinson's disease (PD), many signs of neurodegeneration result from compromised mitochondrial function attributable to specific effects of toxins on the mitochondrial respiratory chain and/or to genetic mutations. Despite these effects being present in almost all cell types, a distinguishing feature of PD is the extreme selectivity of cell loss, which is restricted to the dopaminergic neurons in the ventral portion of the substantia nigra pars compacta. Many hypotheses have been proposed to explain such selectivity, but only recently it has been convincingly shown that the innate autonomous activity of these neurons, which is sustained by their specific Cav1.3 L-type channel pore-forming subunit, is responsible for the generation of basal metabolic stress that, under physiological conditions, is compensated by mitochondrial buffering. However, when mitochondria function becomes even partially compromised (because of aging, exposure to environmental factors or genetic mutations), the metabolic stress overwhelms the protective mechanisms, and the process of neurodegeneration is engaged. The characteristics of Ca2+ handling in neurons of the substantia nigra pars compacta and the possible involvement of PD-related proteins in the control of Ca2+ homeostasis will be discussed in this review