Changes in the surface morphology induced by 1.0‐MeV Au ion bombardment of Ti and Ti‐6Al‐4V

The effects of surface sputtering by 1.0‐MeV Au ion implantation in commercially pure Ti and its alloy Ti‐6Al‐4V have been studied. These materials are associated with applications in orthopaedic implants. There are few studies that try to explain the ion implantation process of Au in these materials when considering the effects generated on the surface by sputtering, especially at energies of the order of MeV. Discs of these materials were mirror polished and then implanted with 1.0‐MeV Au ions for 4.7 × 10¹⁷ ions/cm² at 45° incident angle with respect to the surface. Part of the eroded material was deposited simultaneously on glass slides to determine their spatial distribution. These discs and the slides were analysed by Rutherford backscattering spectroscopy (RBS), scanning electron microscopy (SEM), optical microscopy and atomic force microscopy. The implanted materials show the initial production of surface ripples that evolve into banded structures. Copyright © 2014 John Wiley & Sons, Ltd.     

Graphene-induced apoptosis in lung epithelial cells through EGFR

Expanding interest in nanotechnology applied to electronic and biomedical fields has led to fast-growing development of various nanomaterials. Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms with unique physical and chemical properties. Recently, graphene has been used in many studies on electronics, photonics, composite materials, energy generation and storage, sensors, and biomedicine. However, the current health risk assessment for graphene has been relatively limited and inconclusive. This study evaluated the toxicity effects of graphene on the airway epithelial cell line BEAS-2B, which represents the first barrier of the human body to interact with airborne graphene particles. Our result showed that graphene can induce the cellular Ca²⁺ by phospholipase C (PLC) associated pathway by activating epidermal growth factor receptor (EGFR). Subsequently, inositol 1,4,5-triphosphate (IP₃) receptors activate the release of Ca²⁺ from the endoplasmic reticulum (ER) Ca²⁺ stores. Those Ca²⁺ signals further trigger the calcium-regulated apoptosis in the cell. Furthermore, the stimulation can cause EGFR upregulation, which have been demonstrated to associate with diseases such as lung cancer, chronic obstructive pulmonary disease (COPD), and cardiovascular diseases. This study highlights the additional health risk considering that it can function as a contributing factor for other respiratory diseases.     

Multi-residue method for trace pesticide analysis in soils by LC-QQQ-MS/MS and its application to real samples

ABSTRACT

A method for the simultaneous determination of 30 pesticides residues in soil was developed and validated. Among the studied agrochemicals, there are herbicides (auxines, sulfonylureas, fops, imidazolinones), fungicides (azoles) and insecticides (organophosphorus) widely used in extensive agricultural activities in Uruguay. Five methods with different extraction times, type and amount of solvent, as well as the possibility of a clean-up step were compared in terms of percentage of recovery and repeatability. The final method was based on the extraction of the pesticides’ residues from soil using two successive solvent extraction steps. First, the soil was extracted with methanol in an orbital shaker for 4 h. Secondly, the solid residue was re-extracted overnight with ultrapure water. The methanolic extract was concentrated under vacuum, whereas the aqueous solution was passed through an OASIS HLB® cartridge, eluted with an appropriate solvent and concentrated under nitrogen stream. Both extracts were finally combined and analysed by LC-QQQ-MS/MS using the Document SANTE/11,945/2015 criteria. Recovery percentages at 1 and 10 μg kg^?1 for the studied compounds were in the range 70106% with relative standard deviations below 19 %. The quantification was performed using matrix-matched calibration curves as some compounds presented very strong signal suppression. Residuals of the matrix-matched calibration curves were below 20% for all the validated analytes. The quantification limit was1 μg kg^?1. The method also allows the screening of 11 pesticides in soil. Sixty-five real samples collected from regions where the use of pesticides is intensive were analysed. Quinclorac, tebuconazole, penoxsulam and clomazone were the most frequently pesticides detected.     

Environmental Radioactivity Measurements of Egyptian Soils

Soil and vegetation samples from 33 sites within the northwestern area of the River Nile delta in Egypt have been analyzed for natural and man-made radioactivity. Gamma-ray spectrometric measurements were performed where ²¹⁴Bi and ²¹⁴Pb were used for ²³⁸U-series determinations, while ²⁰⁸Tl and ²²⁸Ac were used for ²³²Th-series determinations. In addition, alpha-spectrometric measurements were also performed for the determination of different isotopes of uranium and plutonium. Other parameters examined included the determination of radium equivalent activities and relationship between the gamma-radiation values and subsequent dose level determinations and the soil types.     

Intramolecular stable carbon isotopic analysis of archaeal glycosyl tetraether lipids

Glycolipids are prominent constituents in the membranes of cells from all domains of life. For example, diglycosyl‐glycerol dibiphytanyl glycerol tetraethers (2Gly‐GDGTs) are associated with methanotrophic ANME‐1 archaea and heterotrophic benthic archaea, two archaeal groups of global biogeochemical importance. The hydrophobic biphytane moieties of 2Gly‐GDGTs from these two uncultivated archaeal groups exhibit distinct carbon isotopic compositions. To explore whether the isotopic compositions of the sugar headgroups provide additional information on the metabolism of their producers, we developed a procedure to analyze the δ¹³C values of glycosidic headgroups. Successful determination was achieved by (1) monitoring the contamination from free sugars during lipid extraction and preparation, (2) optimizing the hydrolytic conditions for glycolipids, and (3) derivatizing the resulting sugars into aldononitrile acetate derivatives, which are stable enough to withstand a subsequent column purification step. First results of δ¹³C values of sugars cleaved from 2Gly‐GDGTs in two marine sediment samples, one containing predominantly ANME‐1 archaea and the other benthic archaea, were obtained and compared with the δ¹³C values of the corresponding biphytanes. In both samples the dominant sugar headgroups were enriched in ¹³C relative to the corresponding major biphytane. This ¹³C enrichment was significantly larger in the putative major glycolipids from ANME‐1 archaea (～15‰) than in those from benthic archaea (<7‰). This method opens a new analytical window for the examination of carbon isotopic relationships between sugars and lipids in uncultivated organisms. Copyright © 2010 John Wiley & Sons, Ltd.