Denitrification-derived nitric oxide modulates biofilm formation in Azospirillum brasilense

Azospirillum brasilense is a rhizobacterium that provides beneficial effects on plants when they colonize roots. The formation of complex bacterial communities known as biofilms begins with the interaction of planktonic cells with surfaces in response to appropriate signals. Nitric oxide (NO) is a signaling molecule implicated in numerous processes in bacteria, including biofilm formation or dispersion, depending on genera and lifestyle. Azospirillum brasilense Sp245 produces NO by denitrification having a role in root growth promotion. We analyzed the role of endogenously produced NO on biofilm formation in A. brasilense Sp245 and in a periplasmic nitrate reductase mutant (napA::Tn5; Faj164) affected in NO production. Cells were statically grown in media with nitrate or ammonium as nitrogen sources and examined for biofilm formation using crystal violet and by confocal laser microscopy. Both strains formed bio- films, but the mutant produced less than half compared with the wild type in nitrate medium showing impaired nitrite production in this condition. NO measurements in biofilm confirmed lower values in the mutant strain. The addition of a NO donor showed that NO influences biofilm formation in a dose-dependent manner and reverses the mutant phenotype, indicating that Nap positively regulates the formation of biofilm in A. brasilense Sp245.Fil: Arruebarrena Di Palma, Andrés. Universidad Nacional de Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pereyra, Cintia Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Moreno Ramírez, Lizbeth. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Xiqui Vazquez, Maria L.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Baca, Beatriz E.. Benemérita Universidad Autónoma de Puebla; MéxicoFil: Pereyra, María Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lamattina, Lamattina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Creus, Cecilia Mónica. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Field enhancement and spectral features of hexagonal necklaces of silver nanoparticles for enhanced nonlinear optical processes

Access to the online abstract in the journal: https://doi.org/10.1364/OE.26.022394 © 2018 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reservedThe nonlinear properties of hybrid metallic-dielectric systems are attracting great interest due to their potential for the enhancement of frequency conversion processes at nanoscale dimensions. In this work, we theoretically and experimentally address the correlation between the near field distribution of hexagonal plasmonic necklaces of silver nanoparticles formed on the surface of a LiNbO3 crystal and the second harmonic generation (SHG) produced by this nonlinear crystal in the vicinities of the necklaces. The spectral response of the hexagonal necklaces does not depend on the polarization direction and is characterized by two main modes, the absorptive high-energy mode located in the UV spectral region and the lower energy mode, which is strongly radiant and extends from the visible to the near infrared region. We show that the spatial distribution of the enhanced SHG is consistent with the local field related to the low energy plasmon mode, which spectrally overlaps the fundamental beam. The results are in agreement with the low absorption losses of this mode and the two-photon character of the nonlinear process and provide deeper insight in the connection between the linear and nonlinear optical properties of the hybrid plasmonic-ferroelectric system. The study also highlights the potential of hexagonal necklaces as useful plasmonic platforms for enhanced optical processes at the nanoscaleSpanish Ministry of Economy and Competitiveness (MINECO) under project MAT2016- 76106-R and the Comunidad de Madrid (grant S2013/MIT-2740). C.T. acknowledges funding from the VILLUM Foundation (Villum Investigator, grant no. 16498). L.E.B and M.O.R also acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through The “María de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377

Desprendimiento de descemet: A propósito de un caso

The detachment of Descemet's membrane of the cornea is not a rare complication with any surgery of the anterior eye segment. Its identification and the actions to be taken in case it occurs are a necessary knowledge for any ophthalmologist. A review of the literature on this topic was conducted in relation to the presentation of a case with this diagnosis.El desprendimiento de la membrana de descemet de la córnea, es una complicación no infrecuente en cualquier cirugía del segmento anterior del ojo. Su identificación, así como la conducta a seguir ante ella son conocimientos necesarios para todo oftalmólogo. Se realiza una revisión bibliográfica del tema a propósito de la presentación de un caso con este diagnóstico

Neural bearing faults classifier using inputs based on Fourier and wavelet packet transforms

RESUMEN: En este artículo se propone y se evalúa experimentalmente un método de diagnóstico de fallas en rodamientos utilizando la clasificación de patrones provenientes de las señales de las vibraciones mecánicas. El método utiliza pre-procesamientos con las transformadas de Fourier y wavelet packet para luego alimentar una red neuronal clasificadora que determina el tipo de fallo. Para evaluar las variables de entrada se realiza un análisis de varianza ANOVA comparando el efecto que tienen los factores: velocidad, carga, falla en pista externa y falla en elemento rodante sobre cada uno de los parámetros propuestos como entradas para las redes neuronales artificiales (RNA). Una vez seleccionadas las variables de entrada más adecuadas, se realiza la búsqueda del clasificador más apropiado explorando diversas configuraciones de red neuronal. Se han entrenado alrededor de 2000 RNA con el propósito de encontrar el clasificador más adecuado. Los resultados de validación muestran que para el algoritmo de entrenamiento tipo gradiente conjugado escalado (trainscg) se alcanza un porcentaje de éxito en la clasificación del 88,5 %, mientras que para el algoritmo de entrenamiento de Levenberg-Marquardt (trainlm) se logra un 91,8 %. Adicionalmente, se resalta que en 7 ocasiones se logró el 100 % de aciertos en la clasificación.ABSTRACT: In this paper one method for bearings diagnosis is proposed and evaluated. This method use signal pattern recognition from mechanical vibrations. Wavelet and Fourier transforms are used for pre-processing the signal and an Artificial Neural Network (ANN) is used as a classifier. Analysis of variance (ANOVA) is used for evaluating the ANN inputs. ANOVA is performed to compare the effect of the factors: speed, load, outer race fault and rolling element fault on each of the parameters proposed as inputs of the ANN, looking for the best parameters for classifying the faults. About 2000 ANN structures were trained in order to find the most appropriate classifier. The results show that the average of success in classifying was 88,5 % for the scaled conjugate gradient algorithm (trainscg), while the Levenberg Marquardt algorithm (trainlm) presented 91,8%. Besides, it was possible to achieve 100 % of success in classifying in 7 cases

Incidencia de estrategia constructivista en la inteligencia espacial de estudiantes de ingeniería de la Universidad San Pedro

According to experts in the training of engineers, the main strengths of engineering professionals is spatial intelligence that helps you understand and manage the physical forms of their environment. The purpose of this research is to determine the best teaching strategies that develop spatial intelligence. Graphic Engineering courses career of Industrial Engineering, University San Pedro, were designed using both instruments and paper, as computer support and solid materials that could be engineered for two- and three-dimensional representation. The research has yielded such results that the strategy applied rises by 24% the rate of spatial intelligence of students tested, which is a significantrisk factor increase this capacity, especially considering that the course taught each of them has lasted for only four months. Despite these encouraging results, we believe that subsequently can be performed similar research that considers other factors and assessment methods are perfected, all of which we detail our findings and recommendations.Según los especialistas en la formación de ingenieros, las principales fortalezas de los profesionales de la ingeniería es la inteligencia espacial lo que ayuda a comprender y manejar las formas físicas del ambiente que los rodea. El propósito de la presente investigación es determinar las estrategias pedagógicas que mejor desarrollen la inteligencia espacial. Los cursos de Ingeniería Gráfica de la carrera profesional de Ingeniería Industrial de la Universidad San pedro se diseñaron con el uso tanto con instrumentos y papel como con ayuda informática y materiales sólidos que pudieran ser manipulados para su representación bidimensional y tridimensional. La investigación realizada ha arrojado como resultados que la estrategia aplicada eleva en 24% el índice de inteligencia espacial de los estudiantes evaluados, lo cual es un factor de incremento significativo de esta capacidad, sobre todo considerando que el curso impartido a cada uno de ellos ha tenido una duración de solo cuatro meses. No obstante, estos alentadores resultados pueden ser considerados para realizar investigaciones similares en las que se consideren otros factores y se perfeccionen los métodos de evaluación, lo cual se detallará en nuestras conclusiones y recomendaciones

Advances in xmipp for cryo-electron microscopy: From xmipp to scipion

Xmipp is an open-source software package consisting of multiple programs for processing data originating from electron microscopy and electron tomography, designed and managed by the Biocomputing Unit of the Spanish National Center for Biotechnology, although with contributions from many other developers over the world. During its 25 years of existence, Xmipp underwent multiple changes and updates. While there were many publications related to new programs and functionality added to Xmipp, there is no single publication on the Xmipp as a package since 2013. In this article, we give an overview of the changes and new work since 2013, describe technologies and techniques used during the development, and take a peek at the future of the package

Co-expression network analysis identifies possible hub genes in aging of the human prefrontal cortex

Introducción: el envejecimiento es el principal factor de riesgo para el desarrollo de enfermedades crónicas como el cáncer, la diabetes, el Parkinson y el Alzheimer. El sistema nervioso central es particularmente susceptible al deterioro funcional progresivo asociado con la edad, entre las regiones cerebrales con mayor compromiso se encuentra la corteza prefrontal (cpf). Estudios de transcriptómica de esta región han identificado como características fundamentales del proceso de envejecimiento la disminución de la función sináptica y la activación de las células de la neuroglia. No es claro cuáles son las causas iniciales, ni los mecanismos moleculares subyacentes a estas alteraciones. El objetivo de este estudio fue identificar genes clave en la desregulación transcriptómica en el envejecimiento de la cpf para avanzar en el conocimiento de este proceso. Materiales y métodos: se hizo un análisis de coexpresión de genes de los transcriptomas de 45 personas entre 60 y 80 años con el de 38 personas entre 20 y 40 años. Las redes fueron visualizadas y analizadas usando Cytoscape, se usó citoHubba para determinar qué genes tenían las mejores características topológicas en las redes de coexpresión. Resultados: se identificaron cinco genes con características topológicas altas. Cuatro de ellos —hpca, cacng3, ca10, plppr4— reprimidos y uno sobreexpresado —cryab—. Conclusión: los cuatro genes reprimidos se expresan preferencialmente en neuronas y regulan la función sináptica y la plasticidad neuronal, mientras el gen sobreexpresado es típico de células de la glía y se expresa como respuesta a daño neuronal facilitando la mielinización y la regeneración neuronal.Introduction: Aging is the main risk factor for the development of chronic diseases such as cancer, diabetes, Parkinson’s disease, and Alzheimer’s disease. The central nervous system is particularly susceptible to progressive functional deterioration associated with age, among the brain regions the prefrontal cortex (PFC) has one of the highest involvements. Transcriptomics studies of this brain region have identified the decrease in synaptic function and activation of neuroglia cells as fundamental characteristics of the aging process. The aim of this study was to identify hub genes in the transcriptomic deregulation in the PFC aging to advance in the knowledge of this process. Materials and methods: A gene co-expression analysis was carried out for 45 people 60 to 80 years old compared with 38 people 20 to 40 years old. The networks were visualized and analyzed using Cytoscape; citoHubba was used to determine which genes had the best topological characteristics in the co-expression networks. Results: Five genes with high topological characteristics were identified. Four of them —HPCA, CACNG3, CA10, PLPPR4— were repressed and one was over-expressed —CRYAB—. Conclusion: The four repressed genes are expressed preferentially in neurons and regulate the synaptic function and the neuronal plasticity, while the overexpressed gene is typical of glial cells and is expressed as a response to neuronal damage, facilitating myelination and neuronal regeneration

Evaluación del comportamiento a macro-fisuración por fatiga de mezclas bituminosas modificadas con polvo de neumático

The use of crumb rubber modified bitumen (CRMB) in asphalt mixes is a road engineering technology that has become increasingly important in recent years. Given the many economic and environmental benefits of this type of binder, the goal is to give CRMB the same level of performance as conventional polymermodified bitumen. The appearance and propagation of cracks due to fatigue phenomena is one of the most common distresses affecting road pavements. Since crumb rubber enhances the mechanical properties of asphalt mixes, it can provide a viable solution for fatigue cracking. This paper presents the results of a comparative analysis of the fatigue-cracking behavior of asphalt mixtures manufactured with crumb rubber modified bitumen and polymer-modified bitumen.El empleo de betunes modificados con polvo de neumático usado en la fabricación de mezclas bituminosas es una de las técnicas que mayor auge está teniendo en los últimos años en la ingeniería de carreteras. Dadas sus grandes ventajas económicas y ambientales, este tipo de ligantes pretende conseguir prestaciones similares a la de los betunes modificados con polímeros utilizados habitualmente. La aparición de fisuras debido a fenómenos de fatiga es una de las patologías más comunes en firmes de carretera. Debido a las mejoras de las propiedades mecánicas del betún aportadas tras la incorporación de polvo de neumático, las mezclas fabricadas con estos ligantes se postulan como una posible solución a dicho problema. En este artículo se lleva a cabo un análisis comparativo del comportamiento a fisuración por fatiga realizado sobre mezclas bituminosas fabricadas con betún modificado con polvo de neumático y con polímeros.This research was carried out within the framework of the R + D + i project entitled Proyecto Integrado de Investigación, Desarrollo y Demostración de Tecnologías para la aplicación de neumáticos fuera de uso en firmes de carretera resistentes a la propagación de grietas (ref. IDI-20091076), funded by the Center for Industrial Technological Development (CDTI) of the Ministry of Science and Innovation in Spain

Incidence of complications in breast reconstruction with autologous tissue in a third level hospital

Background: The objective of this study is to analyze the incidence of complications after breast reconstruction with pedicled or free flaps at the hospital general de Mexico "Dr. Eduardo Liceaga”. Methods: A retrospective, single-center study, including 44 female patients, who underwent immediate or delayed breast reconstruction after breast cancer, between 2019 and 2020, and had at least a 2-year follow up, evaluating the association between patient risk factors (age, history of radiotherapy, presence of overweight or obesity and immediate or delayed reconstruction) with the presence of complications such as seroma, hematoma, wound infection or wound dehiscence. We analyzed data with SPSS software, v23.0. Results: There was no statistically significant difference for the presence of complications associated with risk factors studied. Conclusions: We need more prospective, multicenter studies, including larger sample and strict follow up of patients