Rock-magnetic properties of topsoils and urban dust from Morelia (>800,000 inhabitants), Mexico: Implications for anthropogenic pollution monitoring in Mexico’s medium size cities

En el presente trabajo, investigamos la correlación entre algunos parámetros magnéticos y el nivel de contaminación por metales pesados en suelos urbanos de la ciudad de Morelia, en el occidente de México. El estudio magnético fue llevado a cabo en 98 muestras urbanas provenientes de diferentes tipos de uso de suelo. La mayoría de las muestras contienen minerales ferrimagnéticos como responsables de la magnetización, pertenecientes probablemente a las soluciones sólidas de las titanomagnetitas/ titanomaghemitas. Esto es inferido a partir de las mediciones de susceptibilidad en función de la temperatura y de los experimentos de magnetización remanente isotérmica (MRI). Estas mediciones indican además, que la mayoría de las muestras se saturan casi completamente antes de los 300 mT. Adicionalmente, los valores S-200 (S-200 = IRM-200/SIRM, donde IRM-200= magnetización a campo inverso de 200 mT después de la saturación magnética) se encuentran entre 0.7 y 1.0, característicos de minerales de baja coercitividad magnética. Las curvas promedio de magnetización remanente isotérmica de saturación (SIRM) pueden ser usadas como un indicador del nivel de contaminación, ya que estas curvas muestran diferentes valores de saturación de acuerdo al nivel de contaminación por metales pesados: Cu, Ni, Cr y Sr. Estas asociaciones de (titano)magnetitas con metales pesados fueron observadas bajo el Microscopio Electrónico de Barrido, revelando algunos agregados complejos en lugar de las esférulas detectadas comúnmente.In this work, we investigate the correlation between some magnetic parameters and the level of contamination by heavy metals in urban soils from Morelia city, western Mexico. The magnetic study was carried out on 98 urban soils samples belonging to distinct land uses. Most of analyzed samples contain ferrimagnetic minerals as the responsible for magnetization, most probably corresponding to the titanomagnetites/titanomaghemites solid solutions. This is inferred from the susceptibility vs. temperature measurements and the isothermal remanent magnetization (IRM) experiments. These measurements also indicate that most of samples are almost completely saturated before 300 mT. Additionally, the S-200 values (S-200 = IRM-200/ SIRM, where IRM-200= Back-field of 200 mT after magnetic saturation) are between 0.7 and 1.0, characteristic of low coercivity magnetic minerals. The averaged saturation isothermal remanent magnetization (SIRM) curves can be used as an indicator of pollution level, as these curves show different saturation values according to the level of contamination by heavy metals: Cu, Ni, Cr and Sr. These associations of (titano)magnetite with heavy metals were observed by Scanning Electron Microscope revealing some complex aggregates rather than commonly detected spherules.Universidad Nacional Autónoma de México through the projects CONACYT 118971 and PAPIIT IN 22311

Presencia de productos orgánicos en Twitter desde la perspectiva del análisis de redes sociales

El objetivo de esta investigación fue analizar cómo está estructurada la red de actores que hablan de productos orgánicos en Twitter y, a través de la identificación de actores clave, conocer la influencia que ejercen dentro de las redes; al hacerlo, desarrollamos ideas significativas que permitan a los usuarios de medios sociales mejorar su interacción y posición dentro de la red. Se buscaron y descargaron los datos de los términos #organico(a) y #organicos(as) por un periodo de seis meses. Para su procesamiento y estudio, se utilizó el enfoque teórico y metodológico del análisis de redes sociales (ARS). La red general se formó por 14,329 tweets únicos, publicados por 6,667 usuarios, configurando una red de 6,521 vínculos directos. Para entender con mayor detalle las interacciones, se segmentó la red con base en dos tipos de relaciones: (1) retweets y (2) menciones o respuestas, ambas redes mostraron estructuras diferentes. Se encontró que el conjunto de relaciones que estructuran la red social está asociado a productos, países y temas, así como a diversos actores clave. Además, la expresión de los orgánicos en Twitter sigue de cerca la visión general de considerarse benéficos para la salud y el medio ambiente.The objective of this research was to analyse how the network of actors talking about organic products on Twitter is structured and, through the identification of key players, to assess the influence they exert within the networks. Doing this, we develop meaningful ideas that allow social media users to improve their interaction and position on networks. The data of the terms #organico(a) and #organicos(as) were searched and downloaded for a six-month period. For its processing and study, the theoretical and methodological approach of social networks analysis (SNA) was used. The general network was formed by 14,329 unique tweets, published by 6,667 users, shaping a network with 6,521 direct links. To understand the interactions in greater detail, the network was segmented based on two types of relationships: (1) retweets and (2) mentions or replies to, both networks showed different structures. It was found that the set of relationships that structure the social network is associated with products, countries, and topics, as well as several key players. Furthermore, the expression of organic on Twitter closely follows the general vision of being considered beneficial for health as well as the environment.O objetivo desta pesquisa foi analisar como se estrutura a rede de atores que falam sobre produtos orgânicos no Twitter e, por meio da identificação dos atores-chave, conhecer a influência que eles exercem nas redes; Ao fazer isso, desenvolvemos ideias significativas que permitem aos usuários de mídia social melhorar sua interação e posição na rede. Os dados dos termos #organico (a) e #organicos (as) foram pesquisados ​​e baixados por um período de seis meses. Para seu processamento e estudo, utilizou-se a abordagem teórico-metodológica da análise de redes sociais (ARS). A rede geral foi composta por 14.329 tweets únicos, publicados por 6.667 usuários, perfazendo uma rede de 6.521 links diretos. Para compreender mais detalhadamente as interações, a rede foi segmentada com base em dois tipos de relacionamento: (1) retuítes e (2) menções ou respostas, ambas as redes apresentavam estruturas diferentes. Constatou-se que o conjunto de relações que estruturam a rede social está associado a produtos, países e temas, bem como a diversos atores-chave. Além disso, a expressão do orgânico no Twitter segue de perto a visão geral de ser considerado benéfico à saúde e ao meio ambiente

Bioactive bilayered dressing for compromised epidermal tissue regeneration with sequential activity of complementary agents

The article deals with the design, preparation, and evaluation of a new bilayered dressing for application in the healing of compromised wounds. The system is based on the sequential release of two complementary bioactive components to enhance the activation of the regeneration of dermal tissue. The internal layer is a highly hydrophilic and biodegradable film of gelatin and hyaluronic acid (HG), crosslinked with the natural compound genipin, which reacts with the amine groups of gelatin. This film is loaded with the proangiogenic, anti-inflammatory, and antibacterial peptide, proadrenomedullin N-terminal 20 peptide (PAMP), that is released slowly in the wound site. The external layer, more stable and less hydrophilic, is constituted by a biodegradable polyurethane derived from poly(caprolactone) and pluronic L61. This layer is loaded with resorbable nanoparticles of bemiparin (a fractionated low molecular weight heparin), which promotes the activation of growth factors, FGF and VEGF, and provides a good biomechanical stability and controlled permeability of the bilayered dressing. Experiments carried out in mice demonstrate the excellent angiogenic effect of the HG film in the dermal tissue. Application of the bilayered dressing in the wound healing rabbit ear model shows an improved cicatrization of the wound in both ischemic and non-ischemic defects, favoring epithelialization and reducing noticeably the contraction and the inflammation.This work was supported by the CIBER-BBN and a Grant from Spain’s Ministry of Science and Education (SAF2009-13240-C02-01).Peer Reviewe

Characterisation of Bioglass based foams developed via replication of natural marine sponges

A comparative characterisation of Bioglass based scaffolds for bone tissue engineering applications developed via a replication technique of natural marine sponges as sacrificial template is presented, focusing on their architecture and mechanical properties. The use of these sponges presents several advantages, including the possibility of attaining higher mechanical properties than those scaffolds made by foam replica method (up to 4 MPa) due to a decrease in porosity (68-76%) without affecting the pore interconnectivity (higher than 99%). The obtained pore structure possesses not only pores with a diameter in the range 150-500 mm, necessary to induce bone ingrowth, but also pores in the range of 0-200 mm, which are requested for complete integration of the scaffold and for neovascularisation. In this way, it is possible to combine the main properties that a three-dimensional scaffold should have for bone regeneration: interconnected and high porosity, adequate mechanical properties and bioactivity

Oropouche infection a neglected arbovirus in patients with acute febrile illness from the Peruvian coast

Objective: To evaluate the frequency of infection caused by the Oropouche virus (OROV) in 496 patients with acute febrile disease (AFI), whose samples were obtained for the analysis of endemic arboviruses in a previous investigation carried out in 2016. Results: OROV was detected in 26.4% (131/496) of serum samples from patients with AFI. Co-infections with Dengue virus (7.3%), Zika virus (1.8%) and Chikungunya (0.2%) were observed. The most common clinical symptoms reported among the patients with OROV infections were headache 85.5% (112/131), myalgia 80.9% (106/131), arthralgia 72.5% (95/131) and loss of appetite 67.9% (89/131). Headache and myalgia were predominant in all age groups. Both OROV infections and co-infections were more frequent in May, June and July corresponding to the dry season of the region.Revisión por pare

Scalar cosmological perturbations from inflationary black holes

We study the correction to the scale invariant power spectrum of a scalar field on de Sitter space from small black holes that formed during a pre-inflationary matter dominated era. The formation probability of such black holes is estimated from primordial Gaussian density fluctuations. We determine the correction to the spectrum by first deriving the Keldysh propagator for a massless scalar field on Schwarzschild-de Sitter space. Our results suggest that the effect is strong enough to be tested -- and possibly even ruled out -- by observations.Comment: 41 pages, 11 figures, published versio

The Effects of Ash and Black Carbon (Biochar) on Germination of Different Tree Species

Forest fires generate large amounts of ash and biochar, or black carbon (BC), that cover the soil surface, interacting with the soil’s constituents and its seedbank. This study concerns reproductive ecology assessments supported by molecular characterisation to improve our understanding of the effects of fire and fire residues on the germination behaviour of 12 arboreal species with a wide geographic distribution. For this purpose, we analysed the effects of three ash and one BC concentration on the germination of Acacia dealbata Link, A. longifolia (Andrews) Willd., A. mearnsii De Wild., A. melanoxylon R. Br., Pinus nigra Arnold, P. pinaster Aiton, P. radiata D. Don, P. sylvestris L., Quercus ilex L., Q. pyrenaica Willd., Q. robur L., and Q. rubra L. Each tree species was exposed to ash and BC created from its foliage or twigs (except for Q. rubra, which was exposed to ash and BC of Ulex europaeus L.). We monitored germination percentage, the T50 parameter, and tracked the development of germination over time (up to 1 yr). The BC of A. dealbata, P. pinaster, and Q. robur was analysed by pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) to assess the molecular composition. In six species, ash inhibited the germination, while in another five species, germination was not affected by ash or by BC. In Q. rubra, ash and BC stimulated its germination. This stimulating effect of the BC on Q. rubra is likely to be related to the chemical composition of the ash and BC obtained from Ulex feedstock. The BC of U. europaeus has a very different molecular composition than the other BC samples analysed, which, together with other factors, probably allowed for its germination stimulating effects.This study was carried out within the Project 10MDS200007PR, financed by the Xunta de Galicia; the Project AGL2013-48189-C2-2-R, financed by the Ministerio de Economía y Competitividad, Spain; and FEDERS