548 research outputs found
Redox-Active Nanomaterials For Nanomedicine Applications
Nanomedicine utilizes the remarkable properties of nanomaterials for the diagnosis, treatment, and prevention of disease. Many of these nanomaterials have been shown to have robust antioxidative properties, potentially functioning as strong scavengers of reactive oxygen species. Conversely, several nanomaterials have also been shown to promote the generation of reactive oxygen species, which may precipitate the onset of oxidative stress, a state that is thought to contribute to the development of a variety of adverse conditions. As such, the impacts of nanomaterials on biological entities are often associated with and influenced by their specific redox properties. In this review, we overview several classes of nanomaterials that have been or projected to be used across a wide range of biomedical applications, with discussion focusing on their unique redox properties. Nanomaterials examined include iron, cerium, and titanium metal oxide nanoparticles, gold, silver, and selenium nanoparticles, and various nanoscale carbon allotropes such as graphene, carbon nanotubes, fullerenes, and their derivatives/variations. Principal topics of discussion include the chemical mechanisms by which the nanomaterials directly interact with biological entities and the biological cascades that are thus indirectly impacted. Selected case studies highlighting the redox properties of nanomaterials and how they affect biological responses are used to exemplify the biologically-relevant redox mechanisms for each of the described nanomaterials
Estimación de la pérdida de producción de leche en relación con el recuento de células somáticas de leche de tanque
publishedTomo I . Sección: Sistemas Ganaderos-EconomÃa y Gestión. Sesión: EconomÃa II. Ponencia nº 2
Formation and fate of the born-again planetary nebula HuBi 1
We present the first 3D radiation-hydrodynamic simulations on the formation
and evolution of born-again planetary nebulae (PNe), with particular emphasis
to the case of HuBi1, the inside-out PN. We use the extensively-tested GUACHO
code to simulate the formation of HuBi1 adopting mass-loss and stellar wind
terminal velocity estimates obtained from observations presented by our group.
We found that, if the inner shell of HuBi1 was formed by an explosive very late
thermal pulse (VLTP) ejecting material with velocities of 300 km
s, the age of this structure is consistent with that of 200 yr
derived from multi-epoch narrow-band imaging. Our simulations predict that, as
a consequence of the dramatic reduction of the stellar wind velocity and photon
ionizing flux during the VLTP, the velocity and pressure structure of the outer
H-rich nebula are affected creating turbulent ionized structures surrounding
the inner shell. These are indeed detected in Gran Telescopio Canarias MEGARA
optical observations. Furthermore, we demonstrate that the current relatively
low ionizing photon flux from the central star of HuBi1 is not able to
completely ionize the inner shell, which favors previous suggestions that its
excitation is dominated by shocks. Our simulations suggest that the kinetic
energy of the H-poor ejecta of HuBi1 is at least 30 times that of the clumps
and filaments in the evolved born-again PNe A30 and A78, making it a truly
unique VLTP event.Comment: 9 pages, 10 figures, no tables; accepted to MNRA
Estimación de la evaporación/transpiración en un cultivo de viña mediante radiometrÃa térmica
La estimación precisa de la evapotranspiración de cultivo (ETc), asà como su partición
en las componentes evaporativa (E) y transpirativa (T), resultan fundamentales para mejorar
la eficacia en la gestión del riego de cultivos en hilera en regiones áridas y semiáridas. El
objetivo de este trabajo es contribuir a un mejor entendimiento de la partición E/T sobre viña
llevando a cabo un balance de energÃa por separado para las componentes de suelo y de
vegetación. En este trabajo se presentan los resultados de un experimento llevado a cabo
en la finca de Las Tiesas, Albacete, de junio a octubre de 2013. Se instalaron un conjunto de
radiómetros de infrarrojo térmico, apuntando directamente a las plantas y al suelo entre
hileras. Se tomaron medidas de las cuatro componentes de la radiación neta, del flujo de
calor en el suelo, además de variables meteorológicas y parámetros biofÃsicos. Todas las
medidas se almacenaron en intervalos de 15 minutos, y se promediaron después a escala
horaria y diaria. El valor medio observado de ETc fue de 3,1 mm dÃa-1. La evaporación se
estimó en torno al 30%. Los resultados presentados en este trabajo ofrecen una primera
impresión de la partición E/T, y muestran el potencial de la caracterización térmica de la viña
con este finAn accurate estimation of crop evapotranspiration (ETc), and its partition into both
components, soil evaporation (E) and canopy transpiration (T), is known to be critical for a
more effective irrigation scheduling of row-crops in arid and semi-arid environments.
Vineyards are the best example in Mediterranean countries. The aim of this work is to
improve our understanding of the E/T partition in vineyards by establishing a separate energy
balance for soil and canopy components. An experiment was conducted in Las Tiesas
experimental farm, Albacete (Spain), from June to October of 2013. A set of thermal-infrared
radiometers were assembled pointing directly to the plants and the soil between rows.
Measurements of the four components of the net radiation over the canopy and soil heat
fluxes, as well as meteorological variables and biophysical parameters were all collected and
stored every 15-min. Hourly and daily averages were then computed and analyzed. An
average daily ETc value of 3.1 mm day-1 was observed in both sites. Interrow soil evaporation reached as much as 30% of the total ETc. These results provide a first insight into the
partition E/T and show the potential of the vine thermal characterization with this aim.Ministerio de EconomÃa y Competitividad CGL2013-46862-C2-1/2-PUnión Europea, AGL2014-54201-C4-4-RInstituto Nacional de Investigaciones Agrarias RTA 2011-00100-C05-04Instituto Nacional de Investigaciones Agrarias RTA 2014-00049-C05-03Generalitat Valenciana PROMETEOII/2014/08
Novo neonicotinóide associado a regulador de crescimento de insetos, no controle da mosca-branca e do pulgão na cultura do algodão.
Resumo: O objetivo deste trabalho foi avaliar o desempenho da nova molécula quÃmica dinotefuram, pertencente ao grupo dos neonicotinóides, associada a um análogo do hormônio juvenil (piriproxifem), em aplicação foliar, no controle da mosca-branca B. tabaci Biótipo B e do pulgão A. gossypii, em algodoeiro. O delineamento foi em blocos ao acaso com quatro repetições. Os tratamentos foram: testemunha, dinotefuram + piriproxifem a 25 + 12,5; 50 + 12,5; 75 + 12,5; 25 + 25; 50 + 25; 75 + 25 e dinotefuram a 75 g i.a./ha. Cada parcela foi de 48m2. Para aplicação foliar, utilizou-se um pulverizador costal equipado com barra contendo seis pontas cônicas (TXVK-8), propelido por CO2 e volume de 200 L/ha. Foram realizadas avaliações de eficiência dos tratamentos aos 0, 5, 10, 15 e 20 dias após a aplicação, contando-se o número de ninfas de mosca-branca e o número de pulgões em 10 folhas por parcela. Pela análise dos resultados, concluiu-se que o inseticida dinotefuram associado ao piriproxifem, foi eficiente no controle de ninfas de mosca-branca e do pulgão, igualando-se aos padrões já utilizados
Identification of tomato accessions as source of new genes for improving heat tolerance: from controlled experiments to field
Background: Due to global warming, the search for new sources for heat tolerance and the identification of genes involved in this process has become an important challenge as of today. The main objective of the current research was to verify whether the heat tolerance determined in controlled greenhouse experiments could be a good predictor of the agronomic performance in field cultivation under climatic high temperature stress. Results: Tomato accessions were grown in greenhouse under three temperature regimes: control (T1), moderate (T2) and extreme heat stress (T3). Reproductive traits (flower and fruit number and fruit set) were used to define heat tolerance. In a first screening, heat tolerance was evaluated in 219 tomato accessions. A total of 51 accessions were identified as being potentially heat tolerant. Among those, 28 accessions, together with 10 accessions from Italy (7) and Bulgaria (3), selected for their heat tolerance in the field in parallel experiments, were re-evaluated at three temperature treatments. Sixteen tomato accessions showed a significant heat tolerance at T3, including five wild species, two traditional cultivars and four commercial varieties, one accession from Bulgaria and four from Italy. The 15 most promising accessions for heat tolerance were assayed in field trials in Italy and Bulgaria, confirming the good performance of most of them at high temperatures. Finally, a differential gene expression analysis in pre-anthesis (ovary) and post-anthesis (developing fruit) under heat stress among pairs of contrasting genotypes (tolerant and sensitive from traditional and modern groups) showed that the major differential responses were produced in post-anthesis fruit. The response of the sensitive genotypes included the induction of HSP genes, whereas the tolerant genotype response included the induction of genes involved in the regulation of hormones or enzymes such as abscisic acid and transferases. Conclusions: The high temperature tolerance of fifteen tomato accessions observed in controlled greenhouse experiments were confirmed in agronomic field experiments providing new sources of heat tolerance that could be incorporated into breeding programs. A DEG analysis showed the complex response of tomato to heat and deciphered the different mechanisms activated in sensitive and tolerant tomato accessions under heat stress
Quantum mechanical modeling of excited electronic states and their relationship to cathodoluminescence of BaZrO3
First-principles calculations set the comprehension over performance of novel cathodoluminescence (CL) properties of BaZrO3 prepared through microwave-assisted hydrothermal. Ground (singlet, s*) and excited (singlet s** and triplet t** ) electronic states were built from zirconium displacement of 0.2 Å in {001} direction. Each ground and excited states were characterized by the correlation of their corresponding geometry with electronic structures and Raman vibrational frequencies which were also identified experimentally. A kind of optical polarization switching was identified by the redistribution of 4dz2 and 4dxz (Zr) orbitals and 2pz O orbital. As a consequence, asymmetric bending and stretching modes theoretically obtained reveal a direct dependence with their polyhedral intracluster and/or extracluster ZrO6 distortions with electronic structure. Then, CL of the as-synthesized BaZrO3 can be interpreted as a result of stable triplet excited states, which are able to trap electrons, delaying the emission process due to spin multiplicity changes
- …