Mercury removal in wastewater by iron oxide nanoparticles

Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, surface modifiability, reusability, excellent magnetic properties and relative low cost. In this experiment, Fe3O4 and γ-Fe2O3 nanoparticles were synthesized using iron salts and NaOH as precipitation agents, and Aloe Vera as stabilizing agent; then these nanoparticles were characterized by three different measurements: first, using a Zetasizer Nano ZS for their size estimation, secondly UV-visible spectroscopy which showed the existence of resonance of plasmon at λmax∼360 nm, and lastly by Scanning Electron Microscopy (SEM) to determine nanoparticles form. The results of this characterization showed that the obtained Iron oxides nanoparticles have a narrow size distribution (∼100nm). Mercury removal of 70% approximately was confirmed by atomic absorption spectroscopy measurements

Boundedness of Pseudodifferential Operators on Banach Function Spaces

We show that if the Hardy-Littlewood maximal operator is bounded on a separable Banach function space $X(\mathbb{R}^n)$ and on its associate space $X'(\mathbb{R}^n)$, then a pseudodifferential operator $\operatorname{Op}(a)$ is bounded on $X(\mathbb{R}^n)$ whenever the symbol $a$ belongs to the H\"ormander class $S_{\rho,\delta}^{n(\rho-1)}$ with $0<\rho\le 1$, $0\le\delta<1$ or to the the Miyachi class $S_{\rho,\delta}^{n(\rho-1)}(\varkappa,n)$ with $0\le\delta\le\rho\le 1$, $0\le\delta0$. This result is applied to the case of variable Lebesgue spaces $L^{p(\cdot)}(\mathbb{R}^n)$.Comment: To appear in a special volume of Operator Theory: Advances and Applications dedicated to Ant\'onio Ferreira dos Santo

Organic layer formation and sorption of U(vi) on acetamide diethylphosphonate-functionalized mesoporous silica.

Acetamide diethylphosphonate (AcPhos)-functionalized silica has been shown to have a high affinity for U(vi) in pH 2-3 nitric acid. Previous work with AcPhos-functionalized silica has focused on actinide and lanthanide extraction under various conditions, but has shown poor reproducibility in the functionalization process. For this work, four AcPhos-functionalized SBA-15 materials were synthesized and evaluated based on their U(vi) sorption capacity and their stability in nitric acid. Materials synthesized using pyridine as a basic catalyst were shown to form a greater fraction of polymeric structures at the silica surface, which correlated with higher structural integrity upon contact with acidic solutions. Single-pulse 31P and 1H NMR spectra of these materials show evidence of phosphonic acid groups, as well as hydrogen-bonding interactions either between ligands or with the silica surface. Additionally, these materials were found to have significantly higher U(vi) sorption capacities and Keq values than the materials synthesized without pyridine, most likely due to the ion-exchange properties of the phosphonic acid groups. The 31P-31P DQ-DRENAR NMR technique was used to compare the average strength of dipolar coupling interactions between phosphorus atoms for the four materials. Because the strength of dipolar coupling interactions depends on the number and proximity of neighboring spins, this technique provides information about the average density of ligands on the surface. The conventional functionalization procedure yielded materials with the lowest average surface ligand density, while those using extended reaction times and the pyridine base catalyst yielded materials with higher surface ligand densities

Electron Beam Irradiation Dose Dependently Damages the Bacillus Spore Coat and Spore Membrane

Effective control of spore-forming bacilli begs suitable physical or chemical methods. While many spore inactivation techniques have been proven effective, electron beam (EB) irradiation has been frequently chosen to eradicate Bacillus spores. Despite its widespread use, there are limited data evaluating the effects of EB irradiation on Bacillus spores. To study this, B. atrophaeus spores were purified, suspended in sterile, distilled water, and irradiated with EB (up to 20 kGy). Irradiated spores were found (1) to contain structural damage as observed by electron microscopy, (2) to have spilled cytoplasmic contents as measured by spectroscopy, (3) to have reduced membrane integrity as determined by fluorescence cytometry, and (4) to have fragmented genomic DNA as measured by gel electrophoresis, all in a dose-dependent manner. Additionally, cytometry data reveal decreased spore size, increased surface alterations, and increased uptake of propidium iodide, with increasing EB dose, suggesting spore coat alterations with membrane damage, prior to loss of spore viability. The present study suggests that EB irradiation of spores in water results in substantial structural damage of the spore coat and inner membrane, and that, along with DNA fragmentation, results in dose-dependent spore inactivation

A genetic algorithm for resizing and sampling reduction of non-stationary soil chemical attributes optimizing spatial prediction

Aim of study: To evaluate the influence of the parameters of the geostatistical model and the initial sample configuration used in the optimization process; and to propose and evaluate the resizing of a sample configuration, reducing its sample size, for simulated data and for the study of the spatial variability of soil chemical attributes under a non-stationary with drift process from a commercial soybean cultivation area.Area of study: Cascavel, BrazilMaterial and methods: For both, the simulated data and the soil chemical attributes, the Genetic Algorithm was used for sample resizing, maximizing the overall accuracy measure.Main results: The results obtained from the simulated data showed that the practical range did not influence in a relevant way the optimization process. Moreover, the local variations, such as variance or sampling errors (nugget effect), had a direct relationship with the reduction of the sample size, mainly for the smaller nugget effect. For the soil chemical attributes, the Genetic Algorithm was efficient in resizing the sampling configuration, since it generated sampling configurations with 30 to 35 points, corresponding to 29.41% to 34.31% of the initial configuration, respectively. In addition, comparing the optimized and initial configurations, similarities were obtained regarding spatial dependence structure and characterization of spatial variability of soil chemical attributes in the study area.Research highlights: The optimization process showed that it is possible to reduce the sample size, allowing for lesser financial investments with data collection and laboratory analysis of soil samples in future experiments

Whole‐brain dynamics differentiate among cisgender and transgender individuals

How the brain represents gender identity is largely unknown, but some neural differences have recently been discovered. We used an intrinsic ignition framework to investigate whether there are gender differences in the propagation of neural activity across the whole-brain and within resting-state networks. Studying 29 trans men and 17 trans women with gender incongruence, 22 cis women, and 19 cis men, we computed the capability of a given brain area in space to propagate activity to other areas (mean-ignition), and the variability across time for each brain area (node-metastability). We found that both measurements differentiated all groups across the whole brain. At the network level, we found that compared to the other groups, cis men showed higher mean-ignition of the dorsal attention network and node-metastability of the dorsal and ventral attention, executive control, and temporal parietal networks. We also found higher mean-ignition values in cis men than in cis women within the executive control network, but higher mean-ignition in cis women than cis men and trans men for the default mode. Node-metastability was higher in cis men than cis women in the somatomotor network, while both mean-ignition and node-metastability were higher for cis men than trans men in the limbic network. Finally, we computed correlations between these measurements and a body image satisfaction score. Trans men's dissatisfaction as well as cis men's and cis women's satisfaction toward their own body image were distinctively associated with specific networks in each group. Overall, the study of the whole-brain network dynamical complexity discriminates gender identity groups, functional dynamic approaches could help disentangle the complex nature of the gender dimension in the brain

Los delirios: un yacimiento hidrotermal de oro y plata en la región de Vetas, Santander (Colombia)

Los Delirios Au-Ag deposits is located 700 meters northwestern of Vetas city (Departamento de&nbsp;Santander) and consists of quartz-sulfide-oxides veins that cuts quartz-feldspar bearing biotite&nbsp;gneisses from Bucaramanga Gneiss Formation. Three vein systems are determinated:(1) N30-45°W&nbsp;dips 25-40°NW; (2) N10°W dips 60-70°SW; (3) N70°W dips 70°SW o 60°NE. The vein thickness is&nbsp;between 0.45 and 2.0 meters. The veins have a gray color and massive to brecciated and cavernous&nbsp;structures. The ore mineralogy consists in gold, silver, pyrite, chalcopyrite, pyrrhotite, galena,&nbsp;bornite, calcosine, marcasite, covelline, tetrahedrite, ilmenite, magnetite, hematite. Gange minerals&nbsp;are mainly quartz and plagioclase. The alteration of the deposits is phyllic. The gold and silver&nbsp;contents are 0.5-2.0 gr/T y 0.0-6.48 gr/T respectively. Ore mineralogy, wall alteration and dominant&nbsp;Au-Ag-Pb mineralization in the deposits are like epithermal low-sulfidation or adularia-sericite&nbsp;systems.El yacimiento de oro y plata Los Delirios, localizado 700 metros al NW del Municipio de Vetas (Departamento&nbsp;de Santander) consiste en filones cuarzosos con sulfuros y óxidos, que cortan neises cuarzofeldespáticos&nbsp;con biotita de la Unidad Metamórfica Neis de Bucaramanga. Se determinaron tres sistemas de filones (1)&nbsp;rumbo N30-45°W, buzamiento 25-40°NW; (2) rumbo N10°W, buzamiento 60-70°SW; (3) rumbo N70°W,&nbsp;buzamiento 70°SW o 60°NE. Los espesores de estos varían entre 0.45 y 2.0 metros. Los filones presentan un&nbsp;color grisáceo con estructura masiva, presentándose a veces brechoide, cavernosa. La mineralogía de la&nbsp;mena consiste en oro, plata, pirita, calcopirita, pirrotina, galena, bornita, calcosina, marcasita, covelina,&nbsp;tetrahedrita, ilmenita, magnetita, hematita. Los minerales de la ganga son principalmente cuarzo y plagioclasa.&nbsp;La alteración del yacimiento es de tipo fílica. El contenido de oro y plata en el yacimiento varia entre 0.5-2.0&nbsp;gr/T y 0.0 - 6.48 gr/T respectivamente. La mineralogía, alteración y dominancia de los metales Au-Ag-Pb en&nbsp;el depósito, son similares a los yacimientos epitermales de tipo baja sulfuración o adularia-sericita

Los delirios: un yacimiento hidrotermal de oro y plata en la región de Vetas, Santander (Colombia)

Los Delirios Au-Ag deposits is located 700 meters northwestern of Vetas city (Departamento de&nbsp;Santander) and consists of quartz-sulfide-oxides veins that cuts quartz-feldspar bearing biotite&nbsp;gneisses from Bucaramanga Gneiss Formation. Three vein systems are determinated:(1) N30-45°W&nbsp;dips 25-40°NW; (2) N10°W dips 60-70°SW; (3) N70°W dips 70°SW o 60°NE. The vein thickness is&nbsp;between 0.45 and 2.0 meters. The veins have a gray color and massive to brecciated and cavernous&nbsp;structures. The ore mineralogy consists in gold, silver, pyrite, chalcopyrite, pyrrhotite, galena,&nbsp;bornite, calcosine, marcasite, covelline, tetrahedrite, ilmenite, magnetite, hematite. Gange minerals&nbsp;are mainly quartz and plagioclase. The alteration of the deposits is phyllic. The gold and silver&nbsp;contents are 0.5-2.0 gr/T y 0.0-6.48 gr/T respectively. Ore mineralogy, wall alteration and dominant&nbsp;Au-Ag-Pb mineralization in the deposits are like epithermal low-sulfidation or adularia-sericite&nbsp;systems.El yacimiento de oro y plata Los Delirios, localizado 700 metros al NW del Municipio de Vetas (Departamento&nbsp;de Santander) consiste en filones cuarzosos con sulfuros y óxidos, que cortan neises cuarzofeldespáticos&nbsp;con biotita de la Unidad Metamórfica Neis de Bucaramanga. Se determinaron tres sistemas de filones (1)&nbsp;rumbo N30-45°W, buzamiento 25-40°NW; (2) rumbo N10°W, buzamiento 60-70°SW; (3) rumbo N70°W,&nbsp;buzamiento 70°SW o 60°NE. Los espesores de estos varían entre 0.45 y 2.0 metros. Los filones presentan un&nbsp;color grisáceo con estructura masiva, presentándose a veces brechoide, cavernosa. La mineralogía de la&nbsp;mena consiste en oro, plata, pirita, calcopirita, pirrotina, galena, bornita, calcosina, marcasita, covelina,&nbsp;tetrahedrita, ilmenita, magnetita, hematita. Los minerales de la ganga son principalmente cuarzo y plagioclasa.&nbsp;La alteración del yacimiento es de tipo fílica. El contenido de oro y plata en el yacimiento varia entre 0.5-2.0&nbsp;gr/T y 0.0 - 6.48 gr/T respectivamente. La mineralogía, alteración y dominancia de los metales Au-Ag-Pb en&nbsp;el depósito, son similares a los yacimientos epitermales de tipo baja sulfuración o adularia-sericita