Dipicolylamine styryldiazine derivatives: Synthesis and photophysical studies

International audienceDifferent D-π-A push-pull mols. in which dipicolylamine (DPA) is used as the donor group, different diazines as the acceptor groups, and styryl as the π-conjugated spacer have been synthesized in a straightforward manner by aldol condensation of 4-(di-2-picolylamino)benzaldehyde and the appropriate methyldiazine. All of the compds. showed π-π* transitions in the UV or visible region and the emission of yellow-green light upon irradn. Significant red shifts were obsd. in the fluorescence emission maxima of these compds. on increasing the solvent polarity, a finding that suggests the formation of an intramol. charge-sepd. emitting state that is also supported by semi-empirical calcns. In some cases, protonation led to marked color changes, thus showing the ability of these mols. to function as colorimetric pH sensors. The DPA and diazine units can act as coordination sites for metal cations such as Zn2+, Cd2+ or Hg2+, leading to a blue or red shift in the fluorescence spectra due to the change in the intramol. charge transfer properties. This phenomenon could become a powerful tool for the creation of multiple emission colors with a single mol. after suitable design

Greenhouse Spatial Effects Detected in the Barley (Hordeum vulgare L.) Epigenome Underlie Stochasticity of DNA Methylation

Environmental cues are known to alter the methylation profile of genomic DNA, and thereby change the expression of some genes. A proportion of such modifications may become adaptive by adjusting expression of stress response genes but others have been shown to be highly stochastic, even under controlled conditions. The influence of environmental flux on plants adds an additional layer of complexity that has potential to confound attempts to interpret interactions between environment, methylome, and plant form. We therefore adopt a positional and longitudinal approach to study progressive changes to barley DNA methylation patterns in response to salt exposure during development under greenhouse conditions. Methylation-sensitive amplified polymorphism (MSAP) and phenotypic analyses of nine diverse barley varieties were grown in a randomized plot design, under two salt treatments (0 and 75 mM NaCl). Combining environmental, phenotypic and epigenetic data analyses, we show that at least part of the epigenetic variability, previously described as stochastic, is linked to environmental micro-variations during plant growth. Additionally, we show that differences in methylation increase with time of exposure to micro-variations in environment. We propose that subsequent epigenetic studies take into account microclimate-induced epigenetic variability

Meristem micropropagation of cassava (Manihot esculenta) evokes genome-wide changes in DNA methylation

There is great interest in the phenotypic, genetic and epigenetic changes associated with plant in vitro culture known as somaclonal variation. In vitro propagation systems that are based on the use of microcuttings or meristem cultures are considered analogous to clonal cuttings and so widely viewed to be largely free from such somaclonal effects. In this study, we surveyed for epigenetic changes during propagation by meristem culture and by field cuttings in five cassava (Manihot esculenta) cultivars. Principal Co-ordinate Analysis of profiles generated by Methylation Sensitive Amplified Polymorphism (MSAP) revealed clear divergence between samples taken from field-grown cuttings and those recovered from meristem culture. There was also good separation between the tissues of field samples but this effect was less distinct among the meristem culture materials. Application of methylation-sensitive Genotype By Sequencing (msGBS) identified 105 candidate epimarks that distinguish between field cutting and meristem culture samples. Cross referencing the sequences of these epimarks to the draft cassava genome revealed 102 sites associated with genes whose homologues have been implicated in a range of fundamental biological processes including cell differentiation, development, sugar metabolism, DNA methylation, stress response, photosynthesis, and transposon activation. We explore the relevance of these findings for the selection of micropropagation systems for use on this and other crops

Mini AuAg Wavy Nanorods Displaying Plasmon-Induced Photothermal and Photocatalytic Properties

Alloyed AuAg wavy nanorods (wNRs) of approximate to 24.0 nm length and 3.5 nm width are formed by the mild decomposition of the organometallic complex [Au2Ag2(C6F5)(4)(OEt2)(2)](n) in tetrahydrofuran (THF) in the presence of oleic acid. Ligand exchange with l-glutathione (GSH) or poly(ethylene glycol) methyl ether thiol (PEG-SH) leads to water-soluble nanostructures. These AuAg wNRs display tunable size-dependent longitudinal localized surface plasmon resonance (l-LSPR) broad absorptions beyond 750 nm in the near-infrared (NIR) I and II regions. These intense plasmonic absorptions lead to interesting photothermal, catalytic, and photocatalytic properties, including the catalytic reduction of 4-nitrophenol, the photocatalytic reduction of 4-nitrostyrene, or the photocatalytic dehydrogenation of ammonia borane for H-2 release

La imagen y la narrativa como herramientas para el abordaje psicosocial en escenarios de violencia. Ciudad Bogotá

El conflicto armado en Colombia ha dejado una huella profunda en el país, afectando a millones de personas. Por ende, es imperativo entender el impacto de la violencia para identificar los emergentes psicosociales, que son manifestaciones de las consecuencias de la violencia en las personas y comunidades inmersas en el conflicto armado. Un ejemplo ilustrativo de esto es la narrativa de la editorial de la comisión de la verdad del tiempo, capítulo 1, el caso de Luz. Esta historia permite comprender las experiencias traumáticas sufridas por las víctimas del conflicto armado que, a mediano o largo plazo, se ven abocadas al desplazamiento forzado. Este desplazamiento genera traumas psicológicos y deteriora el tejido social. Para abordar el caso de Luz, se plantearon preguntas reflexivas, circulares y estratégicas, diseñadas para resignificar la experiencia de la narradora, explorar sus emociones y llevarla a reflexionar sobre su futuro. Otro ejemplo impactante de las secuelas de la guerra es el caso de El Salado, donde una masacre generó un trauma colectivo en la comunidad, con un impacto negativo tanto social como culturalmente. Para abordar este desafío, se propusieron tácticas de apoyo psicosocial, basándose en un informe analítico de las vivencias documentadas a través de la foto voz, la imagen y la narrativa. Estas herramientas sirven para la reconstrucción de la memoria y la visualización de realidades identificadas en diferentes contextos de la ciudad de Bogotá.The armed conflict in Colombia has left a deep mark on the country, affecting millions of people. Finally, it is imperative to understand the impact of violence to identify psychosocial emergents, which are manifestations of the consequences of violence on people and communities immersed in the conflict armed. An illustrative example of this is the narrative of the publisher of the truth commission of the time, chapter 1, the case of Luz. This story allows us to understand the traumatic experiences suffered by the victims of the armed conflict who, in the medium or long term, are doomed to forced displacement. This displacement generates psychological trauma and deteriorates the social fabric. To address Luz's case, reflective, circular and strategic questions were posed, designed to redefine the narrator's experience, explore her emotions and lead her to reflect on her future. Another shocking example of the aftermath of war is the case of El Salado, where a massacre generated collective trauma in the community, with a negative impact both socially and culturally. To address this challenge, psychosocial support tactics were proposed, based on an analytical report of the experiences documented through photo voice, image and narrative. These tools serve to reconstruct memory and visualize realities identified in different contexts of the city of Bogotá

The Effect of the Stretch-Shortening Cycle in the Force–Velocity Relationship and Its Association With Physical Function in Older Adults With COPD

This study aimed to evaluate the effect of the stretch-shortening cycle (SSC) on different portions of the force–velocity (F–V) relationship in older adults with and without chronic obstructive pulmonary disease (COPD), and to assess its association with physical function. The participants were 26 older adults with COPD (79 ± 7 years old; FEV1 = 53 ± 36% of predicted) and 10 physically active non-COPD (77 ± 4 years old) older adults. The F–V relationship was evaluated in the leg press exercise during a purely concentric muscle action and compared with that following an eccentric muscle action at 10% intervals of maximal unloaded shortening velocity (V0). Vastus lateralis (VL) muscle thickness, pennation angle (PA), and fascicle length (FL) were assessed by ultrasound. Habitual gait speed was measured over a 4-m distance. COPD subjects exhibited lower physical function and concentric maximal muscle power (Pmax) values compared with the non-COPD group (both p < 0.05). The SSC increased force and power values among COPD participants at 0–100 and 1–100% of V0, respectively, while the same was observed among non-COPD participants only at 40–90 and 30–90% of V0, respectively (all p < 0.05). The SSC induced greater improvements in force, but not power, among COPD compared with non-COPD subjects between 50 and 70% of V0 (all p < 0.05). Thus, between-group differences in muscle power were not statistically significant after the inclusion of the SSC (p > 0.05). The SSC-induced potentiation at 50–100% of V0 was negatively associated with physical function (r = -0.40–0.50), while that observed at 80–100% of V0 was negatively associated with VL muscle thickness and PA (r = -0.43–0.52) (all p < 0.05). In conclusion, older adults with COPD showed a higher SSC-induced potentiation compared with non-COPD subjects, which eliminated between-group differences in muscle power when performing SSC muscle actions. The SSC-induced potentiation was associated with lower physical function, VL muscle thickness, and VL PA values. The SSC-induced potentiation may help as a compensatory mechanism in those older subjects with a decreased ability to produce force/power during purely concentric muscle actions

Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers-polypropylene composites

Stiffness is one of the most relevant characteristics of composite materials. Natural wood fibers have demonstrated their ability to increase the Young's moduli of composite materials, and old newspapers are a potential source of reinforcing fibers for composite materials. There are some micromechanic models to predict the Young's modulus of composite materials, and one of the input data is the intrinsic modulus of their fibers. This intrinsic modulus is a value which is difficult or impossible to measure in the case of wood fibers, due to their measures. This paper evaluates the stiffening abilities of old newspaper fibers and the possibility to back calculate the value of the intrinsic Young's Modulus by means of micromechanic models. Different percentages of old newspaper fibers were compounded with polypropylene (PP). Micromechanics of the fibers were obtained using Hirsch model, Cox-Krenchel's model, Tsai-Pagano model and Halpin-Tsai equations. The most important results were the average intrinsic Young's modulus of the fibers, the mean orientation angle and the mean modulus efficiency factor.Serrano, A.; Espinach, FX.; Tresserras, J.; Rey Tormos, RMD.; Pellicer, N.; Mutje Pujol, P. (2014). Macro and micromechanics analysis of short fiber composites stiffness: The case of old newspaper fibers-polypropylene composites. Materials and Design. 55:319-324. doi:10.1016/j.matdes.2013.10.011S3193245

Caracterización experimental y numérica de eventos de crecida extraordinarios en la cuenca del río carcarañá, Argentina

La cuenca del Río Carcarañá (subcuenca de la Cuenca del Plata), es un importante sistema fluvial ubicado en la regióncentral de la República Argentina, que posee un área de más de 50.000 km2. La cuenca se extiende sobre el centrosudeste de la provincia de Córdoba y el sur de la provincia de Santa Fe, siendo esta región unos de los sitios agrícolasmás productivos del país y del mundo. El río Carcarañá posee tres importantes tributarios: (a) río Tercero o Ctalamochita,(b) río Saladillo y (c) arroyo Tortugas. Dichos tributarios contribuyen al escurrimiento total del río Carcarañá, con una granvariabilidad estacional de caudales. En los años 2014 y 2015 se registraron en la cuenca importantes crecidas que provocaron la inundación de numerosas ciudades y campos en el sudeste de la provincia de Córdoba y sur de la provincia deSanta Fe (más de un millón de hectáreas inundadas). Frente a esta problemática fue necesario generar un conocimientomás detallado del comportamiento de la cuenca frente a eventos de crecida, para brindar a los organismos de gestión lainformación necesaria para la toma de decisiones. Es por ello que el objetivo del presente trabajo es caracterizar, de formaexperimental y numérica, el escurrimiento superficial de este sistema fluvial para los eventos de crecida de los años 2014y 2015, con el fin de desarrollar herramientas que permitan a las autoridades de gestión tomar las medidas necesariaspara mitigar los efectos de este tipo de eventos extraordinarios. Para cumplir con esto se realizó la cuantificación de caudales en diferentes puntos de la cuenca (que incluyó la evaluación del funcionamiento de los órganos de descarga de lapresa de Embalse de Río Tercero), mediante el uso de un ADCP diseñado para aguas poco profundas. Con la informaciónobtenida, se determinaron los parámetros hidráulicos del flujo y se realizó el ajuste de curvas Altura-Caudal para nuevesecciones en toda la cuenca y se analizó la evolución de los hidrogramas en diferentes secciones en donde se reflejacómo impacta la operación de los órganos de evacuación del embalse en los caudales escurridos. Finalmente, utilizandola información obtenida de las mediciones de campo se implementaron y calibraron dos modelos hidráulicos unidimensionales del escurrimiento en el cauce del río Tercero en las localidades de Bell Ville y Villa María (ubicadas en la provinciade Córdoba-Argentina). Los resultados obtenidos fueron utilizados en el período 2015/2016 por los organismos de gestiónpara determinar medidas estructurales y no estructurales a implementar.Carcarañá River basin (a sub-basin of La Plata River basin), is an important fluvial system in the central region of Argentina with area of over 50.000km2 . The basin extends over the center-south-east region of the Santa Fe province and center of Cordoba province in one of the most productive agricultural sites of both, the country and the world. The Carcarañá River has three major tributaries: (a) Tercero (Ctalamochita) River, (b) Saladillo River and (c) Tortugas Creek. These tributaries contribute in a different way to the discharge of Carcarañá River with a great seasonal variability of the flows. Major flooding have occurred in the basin in 2014 and 2015 and caused important damages in many towns and farmlands in the southeast region of the Córdoba province and south of Santa Fe province, and about one million of hectares were flooded. Flooding management requires a detailed characterization of the behavior of the fluvial system during flood events. Thus, the objective of this work is to characterize experimentally and numerically the surface flows in the basin for 2014 and 2015 floods events. To achieve this objective, a quantification of flow discharge was performed in different tributaries of the basin (including the quantification of effluent flow discharge of the Río Tercero Dam valves) using an ADCP YSI/SonTek RiverSurveyor S5 designed for shallow waters. The information obtained from field measurements was used to calibrate one-dimensional hydraulic models for two Tercero River reaches at Bell Ville and Villa Maria cities (located in the province of Córdoba, Argentina). In addition rating curves for nine river cross sections were calibrated for different tributaries in the basin. Using this information, the evolutions of the hydrographs in different cross sections were analyzed; thus it has been possible to evaluate how the early reservoir operation of the dams in the upstream basin impacts on the observed flow. The results obtained in this work were used by the government agencies for flood management regulating outflow from the dam and designing the infrastructure for flood mitigation, etcFil: Díaz Lozada, José Manuel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Rodriguez, Carlos Marcelo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; ArgentinaFil: Herrero, Horacio Sebastian Julian. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Heredia Ligorria, Ana Inés. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Estudios Tecnológicos Sobre el Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Estudios Avanzados en Ingeniería y Tecnología. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Estudios Avanzados en Ingeniería y Tecnología; ArgentinaFil: Lopez, Fabian. Ministerio de Agua, Ambiente y Servicios Públicos. - Gobierno de la Provincia de Cordoba. Ministerio de Agua, Ambiente y Servicios Publicos.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Castelló, Edgar. Ministerio de Agua, Ambiente y Servicios Públicos. - Gobierno de la Provincia de Cordoba. Ministerio de Agua, Ambiente y Servicios Publicos.; ArgentinaFil: Brarda, Juan Pablo. Ministerio de Agua, Ambiente y Servicios Públicos. - Gobierno de la Provincia de Cordoba. Ministerio de Agua, Ambiente y Servicios Publicos.; Argentin