A cross-sectional study was conducted to evaluate mercury (Hg) exposure among 910 Pakaan va Indians from the counties of Guajar Mirim and Nova Marmor , Rond nia State, Brazil. Individual hair samples were taken from the occipital region, and Hg was measured by atomic absorption spectrometry with cold vapor generation. Mean Hg in hair samples was 8.37 micro g/g (range 0.52-83.89), indicating high exposure. Young children (< 2 years old) showed a mean Hg of 10.54 micro g/g, and children from 3 to 5 years old had a mean Hg of 9.34 micro g/g. Mercury levels in women (8,91 micro g/g) were higher than in men (7.55 micro g/g), and this difference was significant (t = 3.26; p < 0.01). These results indicate the need for surveillance programs and complementary studies including the Pakaan va Indians in Rond nia State.
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http://dx.doi.org/10.1590/s0102-311x2003000100022 | DOI Listing |
Chem Sci
December 2024
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry & Pharmaceutical Sciences, Guangxi Normal University Guilin 541004 China
Hierarchical supramolecular frameworks are being designed and constructed for various applications, yet the controlled assembly and process understanding incorporating giant building blocks remains a great challenge. Here, we report a strategy of "rivet" substitution and "hinge" linkage for the controlled assembly of the hierarchical supramolecular framework. The replacement of two "rivet" ethylene glycol (EG) molecules for triangular prism [Zn] (a small block in 1) with a 1,3-propanediol (PDO) provides space for a "hinge" linkage from adjacent ligands, thus providing a hierarchical (from micro- to mesopores, from the internal cavity to external surface) supramolecular framework (2) based on a coordinative subblock with the record number of zinc ions ([Zn]).
View Article and Find Full Text PDFLangmuir
December 2024
Institute of Micro/Nano Materials and Devices, Ningbo University of Technology, Ningbo City 315211, PR China.
The phase state of heterogeneous systems prepared on the basis of mixtures of hydrophobic and hydrophilic silica and water, depending on the ratio of component concentrations, and their using as thixotropic agents has been studied. It was found that the dependence of the interfacial energy of water with the surface of the particles of the composite system made on the basis of hydrophilic and hydrophobic silica taken in the proportion of 1:1 as for the individually taken AM-1 has a bell-shaped form with peaks at = 3 and 1.5 g/g, respectively.
View Article and Find Full Text PDFChemistry
January 2025
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, Kunming, 650500, People's Republic of China.
Int J Biol Macromol
December 2024
Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai, Yantai 264006, China; Yantai Zhongke Research Institute of Advanced Materials and Green Chemical Engineering, Yantai 264006, China; State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China. Electronic address:
The poly(L-lactic acid) (PLLA)/ZnO composite membrane with cluster assemblies microstructure was constructed by a combination of non-solvent induced phase separation (NIPS) and the Breath-Figure method. In this novel method, the controllable diffusion rate between solvent and non-solvent was introduced to the system by adjusting the non-solvent solubility parameters. The humidity was adjusted to control non-solvent solubility parameters in the Breath-Figure method, which avoids the instantaneous phase separation induced by direct coagulation of water droplets.
View Article and Find Full Text PDFLangmuir
October 2024
CPCM Departament de Ciència dels Materials i Química Física, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1 - 11, 08028 Barcelona, Spain.
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