On a Simple General Principle of Brain Organization

A possible framework to characterize nervous system dynamics and its organization in conscious and unconscious states is introduced, derived from a high level perspective on the coordinated activity of brain cell ensembles. Some questions are best addressable in a global framework and here we build on past observations about the structure of configurations of brain networks in conscious and unconscious states and about neurophysiological results. Aiming to bind some results together into some sort of coherence with a central theme, the scenario that emerges underscores the crucial importance of the creation and dissipation of energy gradients in brain cellular ensembles resulting in maximization of the configurations in the functional connectivity among those networks that favor conscious awareness and healthy conditions. These considerations are then applied to indicate approaches that can be used to improve neuropathological syndromes.Fil: Perez Velazquez, Jose L.. Ronnin Institute; Estados UnidosFil: Mateos, Diego Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Matemática Aplicada del Litoral. Universidad Nacional del Litoral. Instituto de Matemática Aplicada del Litoral; ArgentinaFil: Guevara Erra, Ramon. Laboratoire Psychologie de la Perception, Cnrs; Franci

Freehand-Steering Locomotion Techniques for Immersive Virtual Environments: A Comparative Evaluation

Virtual reality has achieved significant popularity in recent years, and allowing users to move freely within an immersive virtual world has become an important factor critical to realize. The user’s interactions are generally designed to increase the perceived realism, but the locomotion techniques and how these affect the user’s task performance still represent an open issue, much discussed in the literature. In this article, we evaluate the efficiency and effectiveness of, and user preferences relating to, freehand locomotion techniques designed for an immersive virtual environment performed through hand gestures tracked by a sensor placed in the egocentric position and experienced through a head-mounted display. Three freehand locomotion techniques have been implemented and compared with each other, and with a baseline technique based on a controller, through qualitative and quantitative measures. An extensive user study conducted with 60 subjects shows that the proposed methods have a performance comparable to the use of the controller, further revealing the users’ preference for decoupling the locomotion in sub-tasks, even if this means renouncing precision and adapting the interaction to the possibilities of the tracker sensor

The Role of Native Language and the Fundamental Design of the Auditory System in Detecting Rhythm Changes

Accepted December 13, 2018Purpose: We investigated whether rhythm discrimination is mainly driven by the native language of the listener or by the fundamental design of the human auditory system and universal cognitive mechanisms shared by all people irrespective of rhythmic patterns in their native language. Method: In multiple experiments, we asked participants to listen to 2 continuous acoustic sequences and to determine whether their rhythms were the same or different (AX discrimination). Participants were native speakers of 4 languages with different rhythmic properties (Spanish, French, English, and German) to understand whether the predominant rhythmic patterns of a native language affect sensitivity, bias, and reaction time in detecting rhythmic changes in linguistic (Experiment 2) and in nonlinguistic (Experiments 1 and 2) acoustic sequences. We examined sensitivity and bias measures, as well as reaction times. We also computed Bayes factors in order to assess the effect of native language. Results: All listeners performed better (i.e., responded faster and manifested higher sensitivity and accuracy) when detecting the presence or absence of a rhythm change when the 1st stimulus in an AX test pair exhibited regular rhythm (i.e., a syllable-timed rhythmic pattern) than when the 1st stimulus exhibited irregular rhythm (i.e., stress-timed rhythmic pattern). This result pattern was observed both on linguistic and nonlinguistic stimuli and was not modulated by the native language of the participant. Conclusion: We conclude that rhythm change detection is a fundamental function of a processing system that relies on general auditory mechanisms and is not modulated by linguistic experience.The authors acknowledge support from Spanish Ministry of Economy and Competitiveness Grant PSI2017-82563-P (awarded to A. G. S.), the “Severo Ochoa” Programme for Centres/Units of Excellence in R&D Grant SEV-2015-490 (BCBL), and the Basque Foundation for Science Grant IKERBASQUE (awarded to A. G. S. and M. O.). D. M. G. was supported by Grant PIA/Basal FB0003 from the Chilean Research Council. L. P. was supported by the Spanish Ministry of Economy and Competitiveness via Juan de la Cierva fellowship

Extracellular acidosis enhances Zika virus infection both in human cells and ex-vivo tissue cultures from female reproductive tract

Zika virus (ZIKV) is a flavivirus transmitted by mosquitoes of the genus Aedes, but unlike other flaviviruses, ZIKV can be sexually transmitted by vaginal intercourse. The healthy vaginal pH ranges from 4.0 to 6.0, reaching values of 6.0–7.0 after semen deposition. Here, we report that low extracellular pH values (range 6.2–6.6) dramatically increase ZIKV infection on cell lines of different origin including some derived from the female genital tract and monocyte-derived macrophages. Furthermore, low pH significantly increased ZIKV infection of human ectocervix and endocervix cultured ex-vivo. Enhancement of infection by low pH was also observed using different ZIKV strains and distinct methods to evaluate viral infection, i.e. plaque assays, RT–PCR, flow cytometry, and fluorescence microscopy. Analysis of the mechanisms involved revealed that the enhancement of ZIKV infection induced by low pH was associated with increased binding of the viral particles to the heparan sulphate expressed on the target cell surface. Acidosis represents a critical but generally overlooked feature of the female genital tract, with major implications for sexual transmission diseases. Our results suggest that low vaginal pH might promote male-to-female transmission of ZIKV infection.Fil: Varese, Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Dantas, Ezequiel Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Paletta, Ana Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Fitzgerald, W.. National Institutes of Health; Estados UnidosFil: Di Diego García, Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Cabrerizo, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Erra Diaz, Fernando Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Defelipe, Lucas Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Pallarés, Horacio Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Dodes Traian, Martín Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Gamarnik, Andrea Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Geffner, Jorge Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Remes Lenicov, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Margolis, L.. National Institutes of Health; Estados UnidosFil: Ceballos, Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentin

Microscopy Characterization of Silica-Rich Agrowastes to be used in Cement Binders: Bamboo and Sugarcane Leaves

Agrowastes are produced worldwide in huge quantities and they contain interesting elements for producing inorganic cementing binders, especially silicon. Conversion of agrowastes into ash is an interesting way of yielding raw material used in the manufacture of low-CO2 binders. Silica-rich ashes are preferred for preparing inorganic binders. Sugarcane leaves (Saccharum officinarum, SL) and bamboo leaves (Bambusa vulgaris, BvL and Bambusa gigantea, BgL), and their corresponding ashes (SLA, BvLA, and BgLA), were chosen as case studies. These samples were analyzed by means of optical microscopy, Cryo-scanning electron microscopy (SEM), SEM, and field emission scanning electron microscopy. Spodograms were obtained for BvLA and BgLA, which have high proportions of silicon, but no spodogram was obtained for SLA because of the low silicon content. Different types of phytoliths (specific cells, reservoirs of silica in plants) in the studied leaves were observed. These phytoliths maintained their form after calcination at temperatures in the 350¿850°C range. Owing to the chemical composition of these ashes, they are of interest for use in cements and concrete because of their possible pozzolanic reactivity. However, the presence of significant amounts of K and Cl in the prepared ashes implies a limitation of their applications.The authors thank the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (Projeto CNPq 40174/2013-1) of Brazil for funding the research. The authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia and Materials Department of Universidade Estadual Paulista at Ilha Solteira.Rosello Caselles, J.; Soriano Martínez, L.; Santamarina Siurana, MP.; Akasaki, JL.; Melges, JLP.; Paya Bernabeu, JJ. (2015). Microscopy Characterization of Silica-Rich Agrowastes to be used in Cement Binders: Bamboo and Sugarcane Leaves. Microscopy and Microanalysis. 21(5):1314-1326. https://doi.org/10.1017/S1431927615015019S13141326215Villar-Cociña, E., Morales, E. V., Santos, S. F., Savastano, H., & Frías, M. (2011). Pozzolanic behavior of bamboo leaf ash: Characterization and determination of the kinetic parameters. Cement and Concrete Composites, 33(1), 68-73. doi:10.1016/j.cemconcomp.2010.09.003Tuck, C. O., Perez, E., Horvath, I. T., Sheldon, R. A., & Poliakoff, M. (2012). Valorization of Biomass: Deriving More Value from Waste. Science, 337(6095), 695-699. doi:10.1126/science.1218930Savastano Jr, H., Santos, S. F., Tonoli, G. H. D., Mejia, J. E. B., & Fiorelli, J. (2015). Non-conventional cement-based composites reinforced with vegetable fibers: A review of strategies to improve durability. Materiales de Construcción, 65(317), e041. doi:10.3989/mc.2015.05514Neethirajan, S., Gordon, R., & Wang, L. (2009). Potential of silica bodies (phytoliths) for nanotechnology. Trends in Biotechnology, 27(8), 461-467. doi:10.1016/j.tibtech.2009.05.002Kameník, J., Mizera, J., & Řanda, Z. (2013). Chemical composition of plant silica phytoliths. Environmental Chemistry Letters, 11(2), 189-195. doi:10.1007/s10311-012-0396-9Madani Hosseini, M., Shao, Y., & Whalen, J. K. (2011). Biocement production from silicon-rich plant residues: Perspectives and future potential in Canada. Biosystems Engineering, 110(4), 351-362. doi:10.1016/j.biosystemseng.2011.09.010GALLEGO, L. (2004). Phytolith Assemblages in Grasses Native to Central Argentina. Annals of Botany, 94(6), 865-874. doi:10.1093/aob/mch214Epstein, E. (1999). SILICON. Annual Review of Plant Physiology and Plant Molecular Biology, 50(1), 641-664. doi:10.1146/annurev.arplant.50.1.641Diamond, S. (1975). A review of alkali-silica reaction and expansion mechanisms 1. Alkalies in cements and in concrete pore solutions. Cement and Concrete Research, 5(4), 329-345. doi:10.1016/0008-8846(75)90089-7Le Blond, J. S., Williamson, B. J., Horwell, C. J., Monro, A. K., Kirk, C. A., & Oppenheimer, C. (2008). Production of potentially hazardous respirable silica airborne particulate from the burning of sugarcane. Atmospheric Environment, 42(22), 5558-5568. doi:10.1016/j.atmosenv.2008.03.018Diamond, S. (1976). A review of alkali-silica reaction and expansion mechanisms 2. Reactive aggregates. Cement and Concrete Research, 6(4), 549-560. doi:10.1016/0008-8846(76)90083-1Li, B., Song, Z., Wang, H., Li, Z., Jiang, P., & Zhou, G. (2014). Lithological control on phytolith carbon sequestration in moso bamboo forests. Scientific Reports, 4(1). doi:10.1038/srep05262Frías, M., Savastano, H., Villar, E., Sánchez de Rojas, M. I., & Santos, S. (2012). Characterization and properties of blended cement matrices containing activated bamboo leaf wastes. Cement and Concrete Composites, 34(9), 1019-1023. doi:10.1016/j.cemconcomp.2012.05.005Prychid, C. J., Rudall, P. J., & Gregory, M. (2003). Systematics and Biology of Silica Bodies in Monocotyledons. The Botanical Review, 69(4), 377-440. doi:10.1663/0006-8101(2004)069[0377:sabosb]2.0.co;2Nzihou, A. (2010). Toward the Valorization of Waste and Biomass. Waste and Biomass Valorization, 1(1), 3-7. doi:10.1007/s12649-010-9014-xFrías, M., Villar-Cociña, E., & Valencia-Morales, E. (2007). Characterisation of sugar cane straw waste as pozzolanic material for construction: Calcining temperature and kinetic parameters. Waste Management, 27(4), 533-538. doi:10.1016/j.wasman.2006.02.017Ma, J. F., & Yamaji, N. (2006). Silicon uptake and accumulation in higher plants. Trends in Plant Science, 11(8), 392-397. doi:10.1016/j.tplants.2006.06.007Rodrigues, M. S., Beraldo, A. L., Savastano Júnior, H., & Santos, S. F. (2013). Cinza de palha de cana-de-açúcar como adição mineral em fibrocimento. Revista Brasileira de Engenharia Agrícola e Ambiental, 17(12), 1347-1354. doi:10.1590/s1415-43662013001200014Le Blond, J. S., Horwell, C. J., Williamson, B. J., & Oppenheimer, C. (2010). Generation of crystalline silica from sugarcane burning. Journal of Environmental Monitoring, 12(7), 1459. doi:10.1039/c0em00020eTeixeira, S. R., Souza, A. E., Carvalho, C. L., Reynoso, V. C. S., Romero, M., & Rincón, J. M. (2014). Characterization of a wollastonite glass-ceramic material prepared using sugar cane bagasse ash (SCBA) as one of the raw materials. Materials Characterization, 98, 209-214. doi:10.1016/j.matchar.2014.11.003Aprianti, E., Shafigh, P., Bahri, S., & Farahani, J. N. (2015). Supplementary cementitious materials origin from agricultural wastes – A review. Construction and Building Materials, 74, 176-187. doi:10.1016/j.conbuildmat.2014.10.010Mohapatra, S., Sakthivel, R., Roy, G. S., Varma, S., Singh, S. K., & Mishra, D. K. (2011). Synthesis of β-SiC Powder from Bamboo Leaf in a DC Extended Thermal Plasma Reactor. Materials and Manufacturing Processes, 26(11), 1362-1368. doi:10.1080/10426914.2011.557127MOTOMURA, H., FUJII, T., & SUZUKI, M. (2006). Silica Deposition in Abaxial Epidermis before the Opening of Leaf Blades of Pleioblastus chino (Poaceae, Bambusoideae). Annals of Botany, 97(4), 513-519. doi:10.1093/aob/mcl01

Snazer: the simulations and networks analyzer

<p>Abstract</p> <p>Background</p> <p>Networks are widely recognized as key determinants of structure and function in systems that span the biological, physical, and social sciences. They are static pictures of the interactions among the components of complex systems. Often, much effort is required to identify networks as part of particular patterns as well as to visualize and interpret them.</p> <p>From a pure dynamical perspective, simulation represents a relevant <it>way</it>-<it>out</it>. Many simulator tools capitalized on the "noisy" behavior of some systems and used formal models to represent cellular activities as temporal trajectories. Statistical methods have been applied to a fairly large number of replicated trajectories in order to infer knowledge.</p> <p>A tool which both graphically manipulates reactive models and deals with sets of simulation time-course data by aggregation, interpretation and statistical analysis is missing and could add value to simulators.</p> <p>Results</p> <p>We designed and implemented <it>Snazer</it>, the simulations and networks analyzer. Its goal is to aid the processes of visualizing and manipulating reactive models, as well as to share and interpret time-course data produced by stochastic simulators or by any other means.</p> <p>Conclusions</p> <p><it>Snazer </it>is a solid prototype that integrates biological network and simulation time-course data analysis techniques.</p

Synthetic Mimic of Antimicrobial Peptide with Nonmembrane-Disrupting Antibacterial Properties

Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The proteolytic system consists of an extracellularly located serine-proteinase, transport systems specific for di-tripeptides and oligopeptides (> 3 residues), and a multitude of intracellular peptidases. This review describes the properties and regulation of individual components as well as studies that have led to identification of their cellular localization. Targeted mutational techniques developed in recent years have made it possible to investigate the role of individual and combinations of enzymes in vivo. Based on these results as well as in vitro studies of the enzymes and transporters, a model for the proteolytic pathway is proposed. The main features are: (i) proteinases have a broad specificity and are capable of releasing a large number of different oligopeptides, of which a large fraction falls in the range of 4 to 8 amino acid residues; (ii) oligopeptide transport is the main route for nitrogen entry into the cell; (iii) all peptidases are located intracellularly and concerted action of peptidases is required for complete degradation of accumulated peptides.