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Resumen: En este artículo exponemos los presupuestos que permiten una reflexión crítica sobre la esfera pública desde una perspectiva marxista. Hemos partido de la consideración del contexto de discusión reciente sobre las ideas políticas de Marx y de la relevancia del concepto de esfera pública para mostrar la importancia de algunos de sus conceptos críticos para la filosofía política. El texto es producto de una investigación dedicada a la elaboración de un marco conceptual que persigue el desarrollo de un análisis crítico de la esfera pública en la actualidad y en el que se ha establecido que algunas cuestiones claves, vinculadas a los conceptos de lenguaje y experiencia, se encontraban presentes en la obra de Marx. En este sentido, el texto presenta una novedosa reflexión al tratar la actualidad del pensamiento de Marx desde el análisis de un problema político contemporáneo que permite poner en evidencia las implicaciones críticas y radicales que poseen sus fundamentos filosófico-críticos para los discursos y las instituciones políticas contemporáneas como la esfera pública. Abstract: This paper presents the presuppositions that enable a critical reflection on the public sphere from a Marxist perspective. It begins by considering the context of recent discussions concerning Marx’s political ideas, and the relevance of the concept of public sphere in order to show the importance of some of Marx’s critical concepts for political philosophy. The text is the result of a research project aimed at constructing a conceptual framework to develop a critical analysis of the public sphere today. This research has already established that some key issues, linked to the concepts of language and experience, were present in Marx’s work. In this sense, the paper presents a novel reflection to the extent that it deals with the actuality of Marx’s thought through the analysis of a contemporary political problem that allows to highlight the critical and radical implications that Marx’s philosophical-critical foundations have for contemporary discourse and political institutions such as the public sphere.

Conventional DNA analysis techniques can hardly detect DNA damage in ruminant spermatozoa due to high DNA compaction in these cells. Furthermore, these techniques cannot discriminate whether the damage is due to oxidative stress. The main purpose of this study was to evaluate the efficacy of two techniques for determining DNA damage in ovine sperm when the source of that damage is oxidative stress. Semen samples from twenty Manchega rams (

RESUMEN En este artículo analizamos críticamente el fenómeno de la crisis de la democracia que se advierte en distintas partes del mundo y proponemos como solución al problema la apreciación de las dinámicas contenciosas que presentan los movimientos sociales. Explicamos en qué medida los problemas de legitimidad que poseen los sistemas políticos representativos han sido causados por la dinámica histórica impuesta por el neoliberalismo, a través de un proceso de desdemocratización de la sociedad, y exponemos las dificultades que existen desde el campo político mismo para encontrar alternativas diferentes al populismo. A partir de allí, sostenemos que los movimientos sociales y sus acciones son la base para una configuración democrática de la sociedad. ABSTRACT In this article, we critically analyze the phenomenon of the crisis of democracy emerging in different parts of the world and propose that the solution to the problem lies in an appreciation of the contentious dynamics presented by social movements. We explain to what extent the problems of legitimacy of representative political systems have been caused by the historical dynamics imposed by neoliberalism, through a process of social de-democratization, and we expose the difficulties that exist in the political field itself to finding alternatives to populism. On this basis, we maintain that social movements and their actions provide the foundations for a democratic configuration of society. RESUMO Neste artigo, analisamos de forma crítica o fenômeno da crise da democracia que é observado em diferentes lugares do mundo e propomos, como solução para o problema, a avaliação das dinâmicas de contenção que os movimentos sociais apresentam. Explicamos em que medida os problemas de legitimidade que os sistemas políticos representativos possuem vêm sendo causados pela dinâmica histórica imposta pelo neoliberalismo, por meio de um processo de desdemocratização da sociedade, além de expormos as dificuldades que há no campo político em si para encontrar alternativas diferentes do populismo. A partir disso, argumentamos que os movimentos sociais e suas ações são a base para uma configuração democrática da sociedade.

Coordinated Cell Motion In article number 2104808 by Swetha Raghuraman, Timo Betz, and co‐workers, a novel migration phenomenon is presented wherein cancer cells burst out from tumor aggregates as an act of pressure release into the surrounding in‐homogeneous soft extra‐cellular matrix (ECM) made up of collagen. The pressure within tumor aggregates manifests due to cellular swelling, leading to a super‐diffusive coordinated expulsion of cells within 12 hours, directed towards regions providing least mechanical resistance [Image: see text]

A key behavior observed during morphogenesis, wound healing, and cancer invasion is that of collective and coordinated cellular motion. Hence, understanding the different aspects of such coordinated migration is fundamental for describing and treating cancer and other pathological defects. In general, individual cells exert forces on their environment in order to move, and collective motion is coordinated by cell-cell adhesion-based forces. However, this notion ignores other mechanisms that encourage cellular movement, such as pressure differences. Here, using model tumors, it is found that increased pressure drove coordinated cellular motion independent of cell-cell adhesion by triggering cell swelling in a soft extracellular matrix (ECM). In the resulting phenotype, a rapid burst-like stream of cervical cancer cells emerged from 3D aggregates embedded in soft collagen matrices (0.5 mg mL

This article belongs to the Section Animal Reproduction., Conventional DNA analysis techniques can hardly detect DNA damage in ruminant spermatozoa due to high DNA compaction in these cells. Furthermore, these techniques cannot discriminate whether the damage is due to oxidative stress. The main purpose of this study was to evaluate the efficacy of two techniques for determining DNA damage in ovine sperm when the source of that damage is oxidative stress. Semen samples from twenty Manchega rams (Ovis aries) were collected and cryopreserved. After thawing, the samples were subjected to different levels of oxidative stress, and DNA oxidation was quantified using an 8-hydroxy-2′-deoxyguanosine (8-OHdG) immunodetection assay and Sperm Chromatin Structure Assay (SCSA®). For this purpose, we evaluated five different concentrations of an oxidation solution (H2O2/FeSO4•7H2O) on ram sperm DNA. Our study with the 8-OHdG immunodetection assay shows that there are higher values for DNA oxidation in samples that were subjected to the highest oxidative stress (8 M H2O2/800 µM FeSO4•7H2O) and those that were not exposed to high oxidative stress, but these differences were not significant (p ≥ 0.05). The two SCSA® parameters considered, DNA fragmentation index (DFI %) and high DNA stainability (HDS %), showed significant differences between samples that were subjected to high concentrations of the oxidation agent and those that were not (p < 0.05). We can conclude that the 8-OHdG immunodetection assay and SCSA® detect DNA damage caused by oxidative stress in ovine sperm under high oxidative conditions; SCSA® is a more straightforward method with more accurate results. For these reasons, an oxidative-stress-specific assay such as 8-OHdG immunodetection is not needed to measure DNA damage caused by oxidative stress in ram sperm samples., Grants PID2020-120281RB-I00 and AGL2017-85603-P were funded by MCIN/AEI/10.13039/501100011033 (Spanish Ministry of Science and Innovation) and, as appropriate, by “ERDF A way of making Europe”, by the “European Union” or by the “European Union NextGenerationEU/PRTR”. Grants SBPLY/17/180501/000369 and SBPLY/21/180501/000111 were funded by the Education and Science Council of Junta de Comunidades de Castilla-La Mancha. P.J.S.-M was supported by a JCCM scholarship, and A.J.-C. was supported by a UCLM scholarship.

This article belongs to the Special Issue Sperm Oxidative Stress., The advent of nanotechnology in the field of animal reproduction has led to the development of safer and more efficient therapies. The use of nanotechnology allows us to avoid the detrimental effects of certain traditional antioxidants, such as Vitamin E. Its hydrophobic nature makes mandatory the use of organic solvents, which are toxic to sperm cells. This study aims to evaluate the efficiency of vitamin E nanoemulsions (NE) on ram (Ovis aries) spermatozoa. For this purpose, the effect of three NE concentrations (6, 12, and 24 mM) were assessed on sperm of 10 mature rams of the Manchega breed. Sperm samples were collected by artificial vagina, pooled, and diluted in Bovine Gamete Medium. The samples were stored at 37 °C and assessed at 0, 4, 8, and 24 h under oxidative stress conditions (100 µM Fe2+/ascorbate). Motility (CASA), viability (YO-PRO/IP), acrosomal integrity (PNA-FITC/IP), mitochondrial membrane potential (Mitotracker Deep Red 633), lipoperoxidation (C11 BODIPY 581/591), intracellular reactive oxygen species (ROS) production and DNA status (SCSA®®) were assessed. A linear mixed-effects models were used to analyze the effects of time, NE, and oxidant (fixed factors) on sperm parameters, and a random effect on the male was also included in the model with Tukey’s post hoc test. Protection of ram spermatozoa with NE resulted in a more vigorous motility under oxidative stress conditions with respect Control and Free vitamin E, while preventing the deleterious effects of oxidative stress coming from the production of free radicals and lipid peroxidation. These results ascertain the high relevance of the use of delivery systems for sperm physiology preservation in the context of assisted reproduction techniques., Grants AGL2017-85603-P, PID2020-120281RB-I00, and PID2020-117788RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 and, as appropriate, by “ERDF A way of making Europe”, by the “European Union”, or by the “European Union NextGenerationEU/PRTR”. A.J.-C. was supported by a UCLM scholarship, and P.J.S.-M. was supported by a JCCM scholarship.

Lettuce is the most cultivated leafy salad vegetable in Colombia, being the municipality of Madrid, in the Department of Cundinamarca, the second largest producer. In this region, lettuce plants with foliar symptoms characterized by brown necrotic spots forming an extended necrotic area, chlorosis, leaf distortion and plant stunting have been detected, possibly caused by a viral infection associated with the Orthotospovirus genus. This study aimed to identify the orthotospovirus species associated with those symptoms, contributing to updating the lettuce phytosanitary status in this region. The presence of orthotospovirus was confirmed by the enzyme-linked immunosorbent assay (DAS-ELISA), although the sequence of the nucleocapsid (N) gene confirmed the presence of Alstroemeria necrotic streak orthotospovirus, disregarding the Tomato spotted wilt orthotospovirus and Impatiens necrotic spot orthotospovirus previously reported for this crop, being this its first report in lettuce crops in Colombia. RESUMO A alface é o vegetal folhoso para salada mais cultivado na Colômbia, sendo o município de Madrid, no Departamento de Cundinamarca, o segundo maior produtor. Nessa região, foram detectadas plantas com sintomas foliares caracterizados por manchas necróticas de coloração castanha formando uma extensa área necrótica, clorose, distorção foliar e atrofia das plantas, causados por infecção viral possivelmente associada ao gênero Orthotospovirus. Objetivou-se identificar as espécies de orthotospovirus associadas aos sintomas, contribuindo para a atualização do estatuto fitossanitário da alface nessa região. Foi constatada a presença de orthotospovirus pelo ensaio de imunoabsorção enzimática (DAS-ELISA), embora a sequência do gene nucleocapsid (N) tenha confirmado a presença de Alstroemeria necrotic streak orthotospovirus, desconsiderando-se o Tomato spotted wilt orthotospovirus e Impatiens necrotic spot orthotospovirus previamente relatados para essa cultura, sendo este o seu primeiro relato para o cultivo de alface na Colômbia.

Collective migration of cells is a key behaviour observed during morphogenesis, wound healing and cancer cell invasion. Hence, understanding the different aspects of collective migration is at the core of further progress in describing and treating cancer and other pathological defects. The standard dogma in cell migration is that cells exert forces on the environment to move and cell-cell adhesion-based forces provide the coordination for collective migration. Here, we report a new collective migration mechanism that is independent of pulling forces on the extra-cellular matrix (ECM), as it is driven by the pressure difference generated inside model tumours. We observe a striking collective migration phenotype, where a rapid burst-like stream of HeLa cervical cancer cells emerges from the 3D aggregate embedded in matrices with low collagen concentration (0.5 mg ml−1). This invasion-like behaviour is recorded within 8 hours post embedding (hpe), and is characterised by high cell velocity and super-diffusive collective motion. We show that cellular swelling, triggered by the soft matrix, leads to a rise in intrinsic pressure, which eventually drives an invasion-like phenotype of HeLa cancer aggregates. These dynamic observations provide new evidence that pressure-driven effects need to be considered for a complete description of the mechanical forces involved in collective migration and invasion.

Artificial active nano- and microparticles driven by light are of special interest since their propulsion can easily be controlled via the illumination. Recently, we have established a propulsion mechanism based on asymmetric light refraction caused by a refractive-index gradient. We will introduce into this new approach based on two-photon polymerization of the active particles, and demonstrate active propulsion under illumination as well as pattern formation in colloidal suspensions of these active particles controlled by light.

Tension and mechanical properties of muscle tissue are tightly related to proper skeletal muscle function, which makes experimental access to the biomechanics of muscle tissue formation a key requirement to advance our understanding of muscle function and development. Recently developed elastic in vitro culture chambers allow for raising 3D muscle tissue under controlled conditions and to measure global tissue force generation. However, these chambers are inherently incompatible with high-resolution microscopy limiting their usability to global force measurements, and preventing the exploitation of modern fluorescence based investigation methods for live and dynamic measurements. Here, we present a new chamber design pairing global force measurements, quantified from post-deflection, with local tension measurements obtained from elastic hydrogel beads embedded in muscle tissue. High-resolution 3D video microscopy of engineered muscle formation, enabled by the new chamber, shows an early mechanical tissue homeostasis that remains stable in spite of continued myotube maturation.

This article belongs to the Special Issue Nanoantioxidants., Oxidative stress has become a major concern in the field of spermatology, and one of the possible solutions to this acute problem would be the use of antioxidant protection; however, more studies are required in this field, as highly contradictory results regarding the addition of antioxidants have been obtained. Vitamin E is a powerful biological antioxidant, but its low stability and high hydrophobicity limit its application in spermatology, making the use of organic solvents necessary, which renders spermatozoa practically motionless. Keeping this in mind, we propose the use of hydrogels (HVEs) and nanoemulsions (NVEs), alone or in combination, as carriers for the controlled release of vitamin E, thus, improving its solubility and stability and preventing oxidative stress in sperm cells. Cryopreserved sperm from six stags was thawed and extended to 30 × 106 sperm/mL in Bovine Gamete Medium (BGM). Once aliquoted, the samples were incubated as follows: control, free vitamin E (1 mM), NVEs (9 mM), HVEs (1 mM), and the combination of HVEs and NVEs (H + N), with or without induced oxidative stress (100 µM Fe2+/ascorbate). The different treatments were analyzed after 0, 2, 5, and 24 h of incubation at 37 °C. Motility (CASA®), viability (YO-PRO-1/IP), mitochondrial membrane potential (Mitotracker Deep Red 633), lipid peroxidation (C11 BODIPY 581/591), intracellular reactive oxygen species production (CM-H2DCFDA), and DNA status (SCSA®) were assessed. Our results show that the deleterious effects of exogenous oxidative stress were prevented by the vitamin E-loaded carriers proposed, while the kinematic sperm parameters (p ˂ 0.05) and sperm viability were always preserved. Moreover, the vitamin E formulations maintained and preserved mitochondrial activity, prevented sperm lipid peroxidation, and decreased reactive oxygen species (ROS) production (p ˂ 0.05) under oxidative stress conditions. Vitamin E formulations were significantly different as regards the free vitamin E samples (p < 0.001), whose sperm kinematic parameters drastically decreased. This is the first time that vitamin E has been formulated as hydrogels. This new formulation could be highly relevant for sperm physiology preservation, signifying an excellent approach against sperm oxidative damage., Grants AGL2017-85603-P, PID2020-120281RB-I00 and PID2020-117788RB-I00 funded by MCIN/AEI/10.13039/501100011033 and, as appropriate, by ERDF A way of making Europe, by the European Union or by the European Union NextGenerationEU/PRTR. A.J.-C. was supported by a UCLM scholarship and P.J.S.-M was supported by a JCCM scholarship.

The mechanical properties and tension of muscle tissue are tightly related to proper skeletal muscle function, which makes experimental access to the biomechanics of muscle tissue development a key requirement to advance our understanding of muscle function and development. Recently developed elastic in vitro culture chambers allow for raising 3D muscle tissue under controlled conditions and measurements of tissue force generation. However, these chambers are inherently incompatible with high resolution microscopy limiting their usability to global force measurements, and preventing the exploitation of modern fluorescence based investigation methods for live and dynamic measurements. Here we present a new chamber design pairing global force measurements, quantified from post deflection, with local tension measurements obtained from elastic hydrogel beads embedded in the muscle tissue. High resolution 3D video microscopy of engineered muscle development, enabled by the new chamber, shows an early mechanical tissue homeostasis that remains stable in spite of continued myotube maturation.

Vitamin E is considered a powerful biological antioxidant; however, its characteristics such as high hydrophobicity and low stability limit its application. We propose to use nanotechnology as an innovative tool in spermatology, formulating nanoemulsions (NE) that accommodate vitamin E, protecting it from oxidation and promoting its release into the medium. The protective effect of the NE against oxidative stress was assessed in red deer epididymal sperm incubated at 37 °C. Cryopreserved sperm from eleven stags were thawed and extended to 400 × 106 sperm/ml in Bovine Gamete Medium (BGM). Once aliquoted, the samples were supplemented with the NE at different concentrations (0, 6 and 12 mM), with or without induced oxidative stress (100 μM Fe2+/ascorbate). The samples were evaluated after 0, 2 and 4 h of incubation at 37 °C. Motility (CASA), viability, mitochondrial membrane potential, acrosomal status, lipoperoxidation (C11 BODIPY 581/591), intracellular reactive oxygen species (ROS) production and DNA status (SCSA®) were assessed. After 2 and 4 h of incubation, the NE were able to prevent the deleterious effects of oxidative stress, thus improving total and progression motility (P ˂0.05). Moreover, the highest concentration tested (12 mM) improved almost every sperm kinematic variable (P ˂0.05) and preserved sperm viability in samples subjected to oxidative stress. In addition, 12 mM of NE protected the acrosomes integrity, maintained and protected mitochondrial activity, prevented sperm lipoperoxidation and reduced ROS production (P ˂0.05) in samples subjected to oxidative stress. This work indicates for the first time that vitamin E formulated in NE could be a new approach against sperm oxidative damage. This could be highly relevant for sperm physiology preservation in the context of assisted reproduction techniques., This research was supported by the Spanish Ministry of Economy, Industry and Competitiveness, MINECO (AGL2017-85603-P) and by Education and Science Council (JCCM, Spain) grant (SBPLY/180501/000369). AJC and MPO were supported by a UCLM scholarship and PJSM was supported by a JCCM scholarship.

La segunda edición de Estructura constitucional del Estado colombiano del profesor John Fernando Restrepo Tamayo, demuestra la madurez y consolidación de su reflexión como docente sobre las instituciones de derecho constitucional que, como se expresa en la introducción del libro, han revolucionado la historia de la nación, transformado el ejercicio del poder, ordenado la manera en que entendemos el sistema de normas propio –que representa la base de una sociedad políticamente organizada– y han puesto a Colombia en la senda constructiva de una comunidad política que se regula a sí misma por medio de principios democráticos y de justicia social.

The promising idea of using self-propelled particles in fields such as microfabrication and environmental remediation has led to the appearance of a plethora of different approaches for their motion during the past years. [1] Among them, the combination of living swimmers and nanocontainer cargos is especially attractive [2]. However, the usual necessity of a fuel in the environment hinders their application in biological tissue and consequently, their bio-medical usage. Here, we propose a novel propulsion mechanism based solely on the refraction of light in the volume of micro-scale particles. In order to understand these artificial swimmers, numerical simulations were undertaken to identify optimized geometries and refractive index distributions of particles. In particles with broken symmetry, a resultant directional photon momentum transfer is intiating a propulsion force, which in turn can be enhanced by the inclusion of a GRadient of refractive INdex (GRIN). We demonstrate fabrication of such artificial swimmers by femtosecond laser lithography based on two photon polymerization (TPP). The versatility of TPP along with the well-suited fabrication polymer Ormocomp allow replicating any of the numerically suggested particles, especially those containing GRIN distributions. We demonstrate the directional motion of the fabricated artificial swimmers under collimated illumination, with the GRIN particles outperforming their homogeneous counterparts. With this first proof-of-principle we pave the way for numerous applications this new generation of fuel-free, refraction-driven self propelled swimmers. [1] M. Guix, S. M. Weiz, O. G. Schmidt, M. Medina‐Sanchez, Part. Part. Syst. Charact. 35, 1700382 (2015). [2] A. Barroso et al., Biomedical Microdevices 17, 26 (2015);A. Barroso et al., SPIE Newsroom (2015); doi:10.1117/2.1201507.006023

Our aim was to optimize 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) immunodetection in order to detect DNA damage caused by oxidative stress that may not be detected by other DNA integrity analysis techniques, especially due to the high compaction of DNA in ruminants. Semen samples from 6 rams were cryopreserved. After thawing, samples were subjected to the DNA oxidation quantification using an 8‐OHdG immunodetection assay by flow cytometry. We have evaluated two different incubation times (30 min vs. overnight) at 4°C of the primary antibody (monoclonal anti‐8‐OHdG antibody). We have also compared the results of this technique with the sperm chromatin structure assay (SCSA®). The analysis revealed that there were no significant differences (p > .05) between different incubation times. However, overnight incubation seems to cause more non‐specific binding of the secondary antibody. Significant differences (p < .05) between subjects and oxidation controls (8 M H2O2/800 μM FeSO4•7H2O) were evident. We can conclude that the 8‐OHdG immunodetection assay for DNA oxidation quantification of ram sperm can be performed subjecting sperm samples to a very high oxidative treatment., This work has been supported by the Spanish Ministry of Economy, Industry and Competitiveness, MINECO (AGL2017‐85603‐P) and by the Education and Science Council of Junta de Comunidades de Castilla‐La Mancha (SBPLY/17/180501/000369).

In electric power systems, it is very common to find problems of power quality. The flow of harmonics significantly affect the operation of three-phase induction motors, and its energy characterization becomes difficult. There are different methods in situ to estimate motor efficiency. However, it is necessary to deepen the in situ efficiency analysis under nonsinusoidal voltage conditions. In this paper, a procedure is presented based on the equivalent circuits with losses segregation and using a bacterial foraging algorithm (BFA). It allows induction motors' energy efficiency determination in field conditions with low invasiveness and working under harmonic distortion. The method was successfully tested on a 1.5 kW motor fed with significant levels of voltage harmonic.

The objective of this work was to analyze an overvoltage case in a rural distribution feeder belonging to an electrical distribution company in the southeast of the Buenos Aires Province in Argentina. The network was modeled in the Electromagnetic Transients Program, based on the electrical parameters that make up the circuit, in order to evaluate its behavior under various switching and load states. The simulation analysis showed that during certain operation and load situations, the conditions for the overvoltage phenomenon occurred, causing a voltage increase in the single-phase transformer feeding. The guidelines for prevention and control of the phenomenon were provided taking into account the results obtained in the study. El objetivo del trabajo presentado fue el de analizar un caso de sobretensión en un sistema de distribución de energía eléctrica rural (13,2kV) perteneciente a una Cooperativa de Electricidad del sudeste de la Policía de Buenos Aires, Rep. Argentina. A partir de los parámetros que componen el circuito eléctrico se modeló la red dentro del entorno del programa computacional Electromagnetic Transients Program, con el fin de evaluar su comportamiento ante distintas maniobras de interrupción y estados de carga. El análisis de la simulación demostró que, en ciertas situaciones de operación y carga, se conjugaron las condiciones para la ocurrencia del fenómeno de ferrorresonancia, ocasionando la elevación de tensión de alimentación en transformadores monofásicos. Considerando los resultados del estudio, se brindaron pautas a tener en cuenta para la prevención y control del fenómeno.

In this work we have studied the transient stability limits in the power system in witch is connected a wind farm with squirrel cage induction generators when the grid is subjected to three-phase short-circuit fault. In order to improve voltage recovery at the terminals of an induction machine and rise a critical clearing time, reactive power injection is used in this work. The models for this work are made with ATP/EMTP program.

Fil: Torcasio, Carlos Horacio. Universidad de Buenos Aires. Facultad de Ciencias Económicas. Buenos Aires, Argentina.