Independent responses to ultraviolet radiation and herbivore attack in broccoli

The plant responses to ultraviolet-B radiation (UV-B) and to insect herbivory are believed to be partially similar. In this study, responses to these factors were investigated in the crop species broccoli (Brassica oleracea L. convar. botrytis, Brassicaceae). Plants were first grown under three UV-B regimes (80%, 23%, and 4% transmittance of ambient UV-B) in greenhouses covered with either innovative materials (high and medium transmittance) or conventional glass (low transmittance). Half of the plants then remained under these conditions, but the other half were transferred to the field with ambient light and herbivore access for up to 3 d. The plant responses to distinct environmental conditions were examined by analysing the morphological and chemical parameters of plants kept inside and plants exposed in the field. Furthermore, suitability of field-exposed plants to naturally occurring insects was investigated in relation to UV-B pretreatment. High levels of UV-B radiation led to increased flavonoid concentrations, but to a lower biomass accumulation in broccoli. These patterns remained after outdoor exposure. However, UV-induced changes of plant traits did not alter attractiveness to herbivorous insects: thrips, whiteflies, and aphids attacked plants independently of UV-B pretreatment. A 3-fold increase of indolyl glucosinolate concentrations occurred in above-ground tissue of all the plants, most likely due to massive herbivore attack after 3 d of field exposure. The results show that plants respond with high specificity to different abiotic and biotic impacts, demonstrating the separate perception and processing of stress factors

Naloxone inhibits nicotine-induced receptor current and catecholamine secretion in bovine chromaffin cells

Nicotine-induced catecholamine (CA) secretion and inward ionic currents were inhibited by the opioid antagonist naloxone in cultured bovine chromaffin cells. Naloxone inhibited nicotine-induced CA secretion, as detected by an on-line real-time electrochemical technique, in a dose-dependent manner (IC50=29 [mu]M). In voltage-clamped chromaffin cells, nicotine (10 [mu]M) evoked an average peak inward current of -146 pA that was inhibited by low concentrations of naloxone (42% at 0.1 [mu]M). The antagonist also inhibited total charge influx associated with nicotinic receptor activation (53% at 0.1 [mu]M). This provides strong evidence that naloxone modulation of nicotine-induced CA secretion does not involve opioid receptors but results from the direct interaction with the nicotinic receptor itself, which might also be the case for other related opioid compounds.http://www.sciencedirect.com/science/article/B6SYR-43MC9YT-C/1/1994796a9d2862757ab52186bcacc5f

Numerical and experimental development of cupronickel filler brazed joints for divertor and first wall components in DEMO fusion reactor

The brazeability of a cupronickel commercial alloy (Cu10Ni) was evaluated for its use as a filler alloy for high- temperature joining of tungsten to the reduced activation ferritic/martensitic steel EUROFER 97 (W-E) and between tungsten base materials (W-W) for its application at the first wall and divertor of future fusion reactors. In addition, given the importance of the residual stresses in these heterogenous joints, a study of the brazing conditions and the impact of the selected filler has been conducted using numerical software to understand its impact on the quality of the joint. Two thermal cycles were evaluated (1165 $^◦$C and 1190$^◦$C) and selected based on the thermal characterization of the filler alloy. The microstructural examination revealed that, in W-E joints, nickel acts as an activator element, reacting and forming interfacial layers at the EUROFER 97 - Cu10Ni interface. In the case of the W-W joints, a lower level of diffusion phenomenon and metallurgical interaction between Cu10Ni and base materials were observed. The hardness profile indicated that the hardening process of EUROFER 97 was associated with the formation of untempered martensite. On the other hand, tungsten kept the received hardness. The me- chanical characterization by shear test reported similar values between both types of joints carried out at 1190$^◦$C but different when the temperature was increased (1165 $^°$C), associated with the brittle character of tungsten and its lower metallurgical interaction. The numerical analysis of the brazing process carried out with ANSYS software shows that residual stresses are accumulated mainly at the interfaces. The information provided by the simulation shows, for a 50 μm filler thickness, the importance of mitigating the residual stress by selecting a filler with an intermediate Coefficient of Thermal Expansion (CTE) that alleviates mechanical stresses relative to the base materials

ORGANIZACIONES EN EL MARCO DE UNA CULTURA SOCIAL INNOVADORA: PROPUESTA DE FACTORES EXPLICATIVOS

En la era de la innovación, la dotación de la infraestructura tecnológica necesaria y otras inversiones en I+D no son suficientes para configurar un ecosistema en el que la innovación sea todo un referente. El verdadero reto reside probablemente en promover y alcanzar un cambio cultural que potencie e interiorice capacidades, valores y relaciones facilitadoras de comportamientos proclives a la innovación tales como la creatividad, la iniciativa personal, la asunción razonable de riesgos, la curiosidad o el emprendizaje. Así, en un intento por analizar en clave global y multidimensional el fenómeno innovador, proponemos el término cultura social innovadora a partir de un análisis multinivel para personas, organizaciones y territorios. De manera concreta, centramos nuestra atención en el área de las organizaciones, y elaboramos una propuesta concreta acerca de aquellos factores clave cuya presencia y despliegue determinaría, a nuestro juicio, el desarrollo secuencial del proceso de innovación, esto es, desde la fase de exploración hasta la etapa de la creación o socialización de la innovación

In situ prey selection of mixotrophic and heterotrophic flagellates in Antarctic oligotrophic lakes: An analysis of the digestive vacuole content

We investigated the selective predation of mixotrophic and heterotrophic flagellates (MF and HF) on different heterotrophic prokaryote phylotypes (HPP; Bacteria + Archaea) living in natural assemblages from oligotrophic Antarctic lakes. In situ prey preference was analyzed for the first time on different mixotrophic taxa (Pseudopedinella sp., Ochromonas-like cells, Chrysophyceae >5 μm). The relative abundances of seven different HPP hybridized by CARD-FISH (catalyzed reporter deposition-fluorescent in situ hybridization) in natural community were compared with the proportions of hybridized cells inside digestive vacuoles. Our results showed some general trends to selectivity over some HPP. Alphaproteobacteria and Betaproteobacteria were the most abundant groups, and strikingly, a negative selection trend was detected in most samples by all bacterivorous protists. In contrast, for Actinobacteria a positive selection trend was observed in most samples, whereas Bacteroidetes seemed to be randomly preyed upon. Interestingly, similar prey preferences were observed in all bacterivorous flagellates. Our results suggest that phylogenetic affiliation determines part of the process of prey selection by protists in these lakes. Nevertheless, other features, such as cell size, morphology and the presence of the S-layer, might also significantly contribute to prey selectivity on the HPP. © 2012 The Author 2012. Published by Oxford University Press. All rights reserved.Fil:Queimaliños, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Schiaffino, M.R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Izaguirre, I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Unrein, F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

In Vitro

Purpose. To evaluate the dose effect of vitamin K3 on wound healing mechanisms. Methods. Conjunctival fibroblasts were incubated for 24 hours. An artificial wound was made and the cells were incubated with fresh medium plus doses of vitamin K3 to be tested. Wound repair was monitored at 0, 18, 24, and 48 hours. Proliferation was measured in actively dividing cells by [3H]thymidine uptake. Six different groups were tested: group 1/no drugs added, group 2/ethanol 0.1%, group 3/vitamin K3 1 mg/L, group 4/vitamin K3 2 mg/L, group 5/vitamin K3 4 mg/L, and group 6/vitamin K3 6 mg/L. Each experiment was carried out in triplicate and 4 times. Results. There were no differences among groups at the initial time. In vitro wound repair was slower in groups 4, 5, and 6. There were no differences between control and ethanol groups and between control and vitamin K3 1 mg/L groups. Fibroblast mitogenic activity was statistically decreased in all vitamin K groups; statistical differences were found among vitamin K3 1 mg/mL and higher doses too. In groups 5 and 6, cellular toxicity was presented. Conclusions. Vitamin K3 is able to inhibit fibroblast proliferation. Vitamin K3 2 mg/L or higher doses inhibit wound healing repair, exhibiting cellular toxicity at 4 and 6 mg/L