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The need of certified reference materials (CRMs) is consistently growing due to various aspects in the environment and communities. A research project on the production of seven environmental CRMs with international collaboration has been proposed as a pilot study. The CRMs are intended to be applied for quality assurance of toxicological, environmental, and food analyses of matrices of soil, sediment, dust, leaves, date fruit, and edible fish muscle for some elements at macro-, micro-, and trace-levels. This article demonstrates stability tests, as an essential parameter for CRMs, of element content in CRMs using ICP OES and ICP-SFMS. Useful and simple approaches were proposed for stability assessment. Cluster analysis of stability revealed that Cu, Fe, Mn, and Al in CRMs of soil matrices were the most similar elements in term of stability; and likewise for Cu, Fe, and Mn in CRMs of biological matrices. An overall stability of all elements in each CRM was also assessed by paired samples t-test at confidence interval of 95%. The p values of all CRMs are all >.05 indicating no significant variation on elements contents before and after underwent storage, besides limited transport conditions. Despite this study presents a simple way for assessment of stability of elements concentrations in CRMs, further stability studies are required concerning several intervals to study the effect of conditions on stability. [ABSTRACT FROM AUTHOR]

Taking advantages of non-destructive techniques, between-bottles homogeneity tests were carried out in term of elemental composition of seven certified reference materials (CRMs) candidates using particle-induced X-ray emission technique (PIXE). A combination of PIXE and RBS techniques (Rutherford backscattering spectrometry) was also used for CRMs candidates having biological matrices. The CRMs candidates have the matrices of soil, sediment, dust, fish muscle, leaves and fruit, which will be certified for some major, minor and trace elements. One batch was produced for each CRM candidate, which included 80 bottles. Between-bottles homogeneity tests were performed for each CRM candidate using seven representative bottles. The repeatability of measurements by PIXE and RBS was examined. The relative standard deviations (RSD) and relative average deviation (RAD) of the elements contents were considered for variability assessment for both repeatability and between-bottles homogeneity. Al, Si and Fe showed good repeatability with RSD and RAD of <4%, while Mg, S, Cl, K, Ca, Mn and Sr showed RSD and RAD in the range of 4–10%. A content of one element in the examined CRMs candidates, with the exception of the date fruit, showed RSD and RAD of <5% indicating good between-bottles homogeneity. For date fruit, the relative error of all elements was <10%, with the exception of Si and Zn, while RAD of S, Cl and K were <10%. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a hmmful metal in the environment that readily enters the food chain when taken up by plants, thus posing a serious threat to human health. In this study, we conducted pot trials to investigate the effects of spermidine (Spd) and L-methionine (Met) on mitigation of Cd-induced toxicity in tomato (Solanum lycopersicum L. Mill.) by using physiological traits and inter-simple sequence repeat markers. The results showed that plants exposed to Cd had reduced photosynthetic pigments ( chlorophyll a and b and carotenoids). Furthermore, the level of hydrogen peroxide (H2O2) was significantly increased by Cd exposure, which in turn elevated plant malondialdehyde and proline content and caused genotoxicity (increased DNA damage and reduced RNA synthesis). However, the application of Spd and Met was found to alleviate Cd toxicity in tomato plants by reducing the content of H2O2 and malondialdehyde, increasing the concentrations of chlorophyll a and b, carotenoids, and proline, and decreasing genotoxicity. Therefore, application of Spd and Met appears to enhance plant defense mechanisms against Cd toxicity and alleviates the negative effects of Cd stress in S. lycopersicum through modification of osmolytes. [ABSTRACT FROM AUTHOR]

Conducting polymers and their composites are receiving considerable attention due to their applications in commercial and domestic appliances based on their electrical, optical and thermal properties. Also the magnetic and conducting properties of ferrite/polypyrrole (PPy) composites have opened a new horizon in multifunctional materials. In the present study, different properties of PPy, holmium substituted ferrite and their composites have been investigated. Prior to that, PPy was prepared by the chemical polymerization method of pyrrole in the presence of FeCl3⋅6H2O. Holmium substituted ferrite Co0.02Ho1.98Fe2O4 was prepared by using co-precipitation technique. The X-ray diffraction (XRD) pattern showed crystalline ferrite phase having an average crystallite size of 27 nm. Composites with different ratios of ferrite and PPy were fabricated using solid state reaction technique. The structural and morphological properties of PPy/Ferrite composites were studied by XRD and scanning electron microscopy (SEM), respectively. Frequency dependent dielectric properties were studied in the range of 1 MHz-3 GHz; the dielectric constant value for composite is higher than that for the holmium ferrite. The higher dielectric constant of the composite indicates that these materials have better ability to store potential energy under the influence of alternating electric field. [ABSTRACT FROM AUTHOR]