Air quality is a major issue for humans owing to the fact that the content of particles in the atmosphere has multiple implications for life quality, ecosystem dynamics and environment. Scientists ...are therefore particularly interested in discovering the origin of airborne particles. A new method has been developed to model the relationship between the emission surface and the total amount of airborne particles at a given distance, employing olive pollen and olive groves as examples. A third-degree polynomial relationship between the air particles at a particular point and the distance from the source was observed, signifying that the nearest area to a point is not that which is most correlated with its air features. This work allows the origin of airborne particles to be discovered and could be implemented in different disciplines related to atmospheric aerosol, thus providing a new approach with which to discover the dynamics of airborne particles.
•Concentric Ring Method (CRM) is a method to model the dynamics of airborne particles.•We model the distance of airborne particles from emission sources.•Most of airborne Olive pollen sources are in the surrounding 209 km.
•A two-stage method for the synthesis of Si QD embedded on ZnO is presented.•An enhanced emission of the ZnO was obtained with the addition of Si quantum dots.•White light emission was produced by ...the contribution of NBE, DBE, and SQDE lines.•The tuning of the photoluminescence emission for the ZnO was obtained.
At the present work, a novel two-stage method for the synthesis of zinc oxide (ZnO) films with silicon quantum dots embedded (SiQDs-ZnO) is reported. The experimental procedure consisting on ZnO matrix produced by the sol-gel technique and silicon quantum dots (Si-QDs) synthesized by a green synthesis is described. The incorporation of the Si-QDs on the ZnO films was obtained by spin coating followed by a post-deposition air annealing at 400 °C. The XPS results show that the Si-QDs were successfully embedded in the ZnO matrix. The effect of the tunable bandgap (Eg) of the ZnO with the addition of Si-QDs was obtained which is consistent with the Burstein-Moss effect. The enhancement of the photoluminescence (PL) of the ZnO films with the increment of Si content is presented.
•The drop plate method was validated by 55 participants in 3 independent trials.•Reliability, minimal heterogeneity among results, and economic benefits were met.•Both methods showed similar number ...of Azospirillum viable cells.•Drop plate method will be included in the REDCAI consensus protocol for Azospirillum spp.
Quality evaluation of commercial inoculants is essential to warrant an adequate crop response to inoculation within a biosecurity framework. In this sense, this work is aimed at standardizing and validating the drop plate method for the enumeration of Azospirillum viable cells as an alternative to the spread plate technique, which is currently proposed in the consensus protocol of the REDCAI network. Between 14 and 25 private and public laboratories participated in three independent trials. We obtained consistent and robust results that allowed to confirm that both techniques are equivalent, concluding that the drop plate method is an alternative enumeration technique that is adequate to be included in the abovementioned consensus protocol.
La evaluación de la calidad de los inoculantes comerciales es fundamental para garantizar una adecuada respuesta de los cultivos a la inoculación dentro de un marco de bioseguridad. En este sentido, el objetivo de este trabajo fue la estandarización y validación de la técnica de la microgota para la cuantificación de Azospirillum como metodología alternativa a la técnica de siembra en superficie, propuesta actualmente en el protocolo consenso de la Red de Calidad de Inoculantes, REDCAI. Entre 14 y 25 laboratorios, tanto privados como públicos, participaron de tres ensayos independientes. A partir de ellos se obtuvieron resultados reproducibles y robustos que permiten confirmar que ambas técnicas son equivalentes y concluir que la técnica de recuento por la microgota es una alternativa adecuada para ser incluida dentro del mencionado protocolo consenso.
Abstract
The SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey has obtained high-resolution spectra for thousands of red giant stars distributed among the massive ...satellite galaxies of the Milky Way (MW): the Large and Small Magellanic Clouds (LMC/SMC), the Sagittarius Dwarf Galaxy (Sgr), Fornax (Fnx), and the now fully disrupted Gaia Sausage/Enceladus (GSE) system. We present and analyze the APOGEE chemical abundance patterns of each galaxy to draw robust conclusions about their star formation histories, by quantifying the relative abundance trends of multiple elements (C, N, O, Mg, Al, Si, Ca, Fe, Ni, and Ce), as well as by fitting chemical evolution models to the
α
/Fe–Fe/H abundance plane for each galaxy. Results show that the chemical signatures of the starburst in the Magellanic Clouds (MCs) observed by Nidever et al. in the
α
-element abundances extend to C+N, Al, and Ni, with the major burst in the SMC occurring some 3–4 Gyr before the burst in the LMC. We find that Sgr and Fnx also exhibit chemical abundance patterns suggestive of secondary star formation epochs, but these events were weaker and earlier (∼5–7 Gyr ago) than those observed in the MCs. There is no chemical evidence of a second starburst in GSE, but this galaxy shows the strongest initial star formation as compared to the other four galaxies. All dwarf galaxies had greater relative contributions of AGB stars to their enrichment than the MW. Comparing and contrasting these chemical patterns highlight the importance of galaxy environment on its chemical evolution.
Exposure to naturally occurring inorganic arsenic (iAs), primarily from contaminated drinking water, is considered one of the top environmental health threats worldwide. Arsenic (+3 oxidation state) ...methyltransferase (AS3MT) is the key enzyme in the biotransformation pathway of iAs. AS3MT catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to trivalent arsenicals, resulting in the production of methylated (MAs) and dimethylated arsenicals (DMAs). MAs is a susceptibility factor for iAs-induced toxicity. In this study, we evaluated the association of the polymorphism in AS3MT gene with iAs metabolism and with the presence of arsenic (As) premalignant skin lesions. This is a case-control study of 71 cases with skin lesions and 51 controls without skin lesions recruited from a iAs endemic area in Mexico. We measured urinary As metabolites, differentiating the trivalent and pentavalent arsenical species, using the hydride generation atomic absorption spectrometry. In addition, the study subjects were genotyped to analyze three single nucleotide polymorphisms (SNPs), A-477G, T14458C (nonsynonymus SNP; Met287Thr), and T35587C, in the AS3MT gene. We compared the frequencies of the AS3MT alleles, genotypes, and haplotypes in individuals with and without skin lesions. Marginal differences in the frequencies of the Met287Thr genotype were identified between individuals with and without premalignant skin lesions (p=0.055): individuals carrying the C (TC+CC) allele (Thr) were at risk odds ratio=4.28; 95% confidence interval (1.0–18.5). Also, individuals with C allele of Met287Thr displayed greater percentage of MAs in urine and decrease in the percentage of DMAs. These findings indicate that Met287Thr influences the susceptibility to premalignant As skin lesions and might be at increased risk for other adverse health effects of iAs exposure.
In this research, we conducted a systematic evaluation of the synthesis parameters of a multi-responsive core-shell nanocomposite (Fe3O4 nanoparticles coated by poly(N-isopropylacrylamide) (PNIPAM) ...in the presence of chitosan (CS) (Fe3O4@PNIPAM-CS). Scanning electron microscopy (SEM) was used to follow the size and morphology of the nanocomposite. The functionalization and the coating of Fe3O4 nanoparticles (Nps) were evaluated by the ζ-potential evolution and Fourier Transform infrared spectroscopy (FTIR). The nanocomposite exhibited a collapsed structure when the temperature was driven above the lower critical solution temperature (LCST), determined by dynamic light scattering (DLS). The LCST was successfully shifted from 33 to 39 °C, which opens the possibility of using it in physiological systems. A magnetometry test was performed to confirm the superparamagnetic behavior at room temperature. The obtained systems allow the possibility to control specific properties, such as particle size and morphology. Finally, we performed vincristine sulfate loading and release tests. Mathematical analysis reveals a two-stage structural-relaxation release model beyond the LCST. In contrast, a temperature of 25 °C promotes the diffusional release model. As a result, a more in-depth comprehension of the release kinetics was achieved. The synthesis and study of a magnetic core-shell nanoplatform offer a smart material as an alternative targeted release therapy due to its thermomagnetic properties.
Airborne pollen monitoring is an effective tool for studying the reproductive phenology of anemophilous plants, an important bioindicator of plant behavior. Recent decades have revealed a trend ...towards rising airborne pollen concentrations in Europe, attributing these trends to an increase in anthropogenic CO2 emissions and temperature. However, the lack of water availability in southern Europe may prompt a trend towards lower flowering intensity, especially in herbaceous plants. Here we show variations in flowering intensity by analyzing the Annual Pollen Index (API) of 12 anemophilous taxa across 12 locations in the Iberian Peninsula, over the last two decades, and detecting the influence of the North Atlantic Oscillation (NAO). Results revealed differences in the distribution and flowering intensity of anemophilous species. A negative correlation was observed between airborne pollen concentrations and winter averages of the NAO index. This study confirms that changes in rainfall in the Mediterranean region, attributed to climate change, have an important impact on the phenology of plants.
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•We studied the airborne pollen of 12 anemophilous taxa in the Iberian Peninsula.•We show variations in flowering intensity over the last two decades.•Results revealed differences in the distribution and flowering intensity.•A negative correlation was observed between airborne pollen and winter NAO index•Changes in rainfall pattern play a key role as driver of climate change effects.
Despite the worldwide increasing incidence and prevalence of Inflammatory Bowel Disease (IBD), our knowledge about it in Mexico is still limited. The aim of this study is to describe the incidence ...and prevalence of IBD as well as its clinical and socio-demographical characteristics in Mexico from a nation-wide perspective.Multicenter nation-wide cohort study that included 42 IBD clinics from all over the country that participated with electronically register of the new cases over 17 years as well as all known existing cases together with their clinical and socio-demographical characteristics from patients with IBD (ulcerative colitis UC, Crohn disease CD, and inflammatory bowel disease unclassified IBDU). The data collection was conducted between January and October 2017. Incidence, prevalence, and mean incidence over 2 decades were then calculated. Data base was analyzed using SPSS v24 program SPSS (version 24, IBM Corp., Armonk, NY, USA).A total of 2645 patients with IBD were registered. The crude incidence rates of IBD, UC, and CD, respectively, were 0.21, 0.16, and 0.04 cases per 100,000-person year. The highest incidence was registered in the year 2015, compared with to the previous years. The mean incidence of IBD has increased steadily from 0.05 to 0.21 per 100,000 person-years over the past 15 years (P = .06). The incidence of IBD new cases have increased significantly throughout the last 16 years, 5.9-fold for IBD, 5.3-fold for UC, and 9.5-fold for CD. The prevalence rates of IBD, UC, and CD, respectively, were 1.83, 1.45, and 0.34 cases per 100,000-person-year.This is the first study from a nation-wide perspective that demonstrated a significant increase of prevalence and incidence of IBD in Mexico in the last 15 years.
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