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Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The extraction of marble from the Rokáfrica mine has generated a mining environmental liability, which is the subject of a chemical and mineralogical characterization in order to determine possible uses of these wastes. For the analysis, five experimental samples were made from a 5,000 kg composite sample. Chemical tests were performed by atomic absorption spectrometry; mineralogical tests were performed by X-ray diffractometry, using the powder method. Significant contents of CaO, SiO2, MgO, Al2O3, Fe2O3, K2O and Na2O were found in these residues, with average CaO and NPK contents of 38.99 % and 4 %, respectively. Quartz, feldspar, micas and carbonates were detected as main mineralogical phases. These results suggest that this mining environmental liability has prospects for use as construction material and for agriculture. [ABSTRACT FROM AUTHOR]

Magnetic iron oxide nanoparticles (NPs) have been widely used as contrast agents in magnetic resonance imaging. In recent years, interest has been focused on obtaining and functionalizing them to make them better vectors and more soluble or specific to a given target. In the present work, we report the synthesis and characterization of NPs functionalized with two naphthalene derivatives (Amylovis®), which exhibit high affinity for ß-amyloid plaques characteristic of Alzheimer's disease (AD). These ones were characterized by FT-IR, TGA, DLS and SEM. The obtained NPs were conjugated by Steglich's method to two different Amylovis® molecules, determined this by ligand differences on the surface of the synthesized NPs. Amylovis® functionalized NPs could be useful for the detection of amyloid plaques that would contribute to an early diagnosis of AD. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study, which compares the effect of the sensitivity against the cementation in the recovering of the stress-strain properties in clayey soils from "Sabana de Bogotá". The work methodology included three phases: (i) extraction of samples; (ii) properties assessment of the undisturbed samples; and (ii) stabilization and analysis of the resistance of the stabilized samples with cemented materials. An experimental plan, which included physical and mechanical tests, was developed. The plan had an emphasis on the assessment of the undrained shear strength and the elastic modulus through unconfined compression tests. The samples were compacted and stabilized with the addition of two solid chemical products, calcium carbonate and iron oxide. Results between natural, remoulded and stabilized were compared by means of statistical methods. Therefore, it was found that the use of iron oxide in this kind of soil allows obtaining stress-strain parameters close to the undisturbed state after the compaction process. [ABSTRACT FROM AUTHOR]

The aim of this work was the synthesis and characterization of iron oxide magnetic nanoparticles coated with silica (Fe3O4@SiO2) intended for plasmid DNA isolation. Synthesis was carried out through co-precipitation method and coating was performed used the Stöber method. Materials were characterized by X-ray fluorescence, X-ray diffraction and Infrared spectroscopy. DNA purification was performed by comparing the ethanolic precipitation method, the QIAprep® commercial DNA purification kit and the synthesized Fe3O4@SiO2. Results showed that is possible to obtain Fe3O4@SiO2 (ranging size from 9 to 12 nm) through the proposed methodology. The amount of Si adsorbed onto the surface of magnetic particles and the crystal size of the Fe3O4@SiO2 were pH and washing-conditions dependent. The isolation assay showed that it is possible to recovery efficiently plasmid DNA using the Fe3O4@SiO2 obtain in normal conditions as solid support. [ABSTRACT FROM AUTHOR]

Copyright of Intersecciones en Antropología is the property of Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Sociales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work we present a comparative study of three methods in obtaining samples at low cost. The samples obtained are nanopaticules of Iron oxide, copper oxide and Titanium nanotubes. The first two were obtained by the Sol-Gel, polymeric precursors and the third sample by the chemical anodization method. The samples were characterized by optical methods such as Raman, X-rays and scanning electron microscopy. The methods used to obtain the samples are chemical methods from which excellent samples can be obtained at a low cost and with the use of simple laboratories, especially in Colombia where the investment in research laboratories is low so far. [ABSTRACT FROM AUTHOR]

We present the results of excavations carried out in an ancient mining site in the Nasca region. Mina Primavera, near the Ingenio valley, is a source of hematite (iron oxide) that was exploited during the first four centuries AD. We have encountered stratigraphic contexts y radiocarbon dates that indicate that the first episodes of exploitation correspond to ceramic material we know as Nasca 1 or Initial Nasca. These discoveries highlight the technological innovations associated with the development of pre-fire ceramic paints as a medium for iconography in the context of a new cult being elaborated at Cahuachi at that time. Moreover, hematite was certainly extracted for other purposes than ceramic paint manufacture, including its use in offerings y the colorings of murals y temple facades. The extraction of minerals from Mina Primavera accelerated during Early Nasca, corresponding to the development of new ritual practices, y apparently ceased with the abandonment of Cahuachi as a ceremonial center, after which the cavity inside the mine may have become (or remained) sacred as something analogous to a huaca. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have studied the effect of an inert second phase Fe2O3, on the thermal and electrical properties of NH4H2PO4. Differential scanning calorimetry (DSC) and impedance spectroscopy (IS) were used. The composites (1-x)NH4H2PO4-(x)Fe2O3, x=0.0 - 0.15, were prepared by mechanical mixing of the components followed by heating at temperatures below the NH4H2PO4 (ADP) melting point at 210 °C. The DSC curves show an anomaly at around 190 °C, which seems to be unaltered by the Fe2O3 content, however, this, is not the case for the reported anomalies at around 157 and 210 °C (m.p). The conductivity increases two orders of magnitude compared with pure ADP, showing a maximum for x=0.05 and a new increase for x=0.15. The experimental results suggest that this behavior can be explained in terms of conduction paths created when the iron phase is introduced. [ABSTRACT FROM AUTHOR]

When organic matter is the principal stabilizing agent and soil aggregates structure is hierarchical, the mechanism of formation of aggregates drives to seclude the organic carbon in stable macroaggregates. This concept comes from research about the way as tillage alters the rate of formation and degradation of aggregates and, consequently, the natural dynamic of particulate organic matter and organomineral associations. There is no local information that corroborate within aggregates organic carbon associated to minerals and better information on the nature and dynamics of organomineral associations will lead to a greater understanding of soil structure dynamics and of carbon cycling and sequestration in soils. These were the aims of this research and free iron oxides associated to organic compounds were chemically removed from soil aggregates in three soil series under continuous cropping with conventional tillage (CCCT) and non-grazed crop-pasture (NGCP). The results showed that ferrihydrite, a low crystallinity oxide, would be part of organomineral associations. The quantity of this mineral would diminish under CCCT, but the magnitude of this result in the three soil series was different. In both management systems, the iron removed of free iron oxides associated to organic compounds was more abundant in macroaggregates than in microaggregates. Under conventional tillage, the iron diminished in maeroaggregates and increased in microaggregates. We suggest that in undisturbed soils the organic carbon associated to mineral sequestration, ferrihydrite, among others, would occur within microaggregates finally confined in stable macroaggregates. [ABSTRACT FROM AUTHOR]

The results of the observation carried out in relation to the wetting achieved with drips of 4 and 8 l/h when it is used in beds shaped on Red Ferralitic Compacted soil with amounts of water of 4, 8, 12 and 16 L. For rising the humid bulbs, Soil samples were taking every 10 cm horizontal and vertically 24 h after irrigation, using the gravimetric method to determine moisture. It was observed a tendency in bulbs to stay opened in this phase, due to soil compactness at depths higher than 40 cm, with humid length of 30 cm that increased as the amount Of water applied increased, getting to maximum levels of 44,1 and 65,9 cm respectively. [ABSTRACT FROM AUTHOR]