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Metal Elements (metal + element)
Selected AbstractsPreparation, morphology, and biolabeling of fluorescent nanoparticles based on conjugated polymers by emulsion polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2010Rui Wang Abstract Novel nanoparticles based on conjugated polymer with good fluorescent properties were synthesized by Suzuki coupling reaction using certain surfactants as one kind of special emulsion polymerization. The luminescent properties of the prepared nanoparticles could be controlled by selecting different monomers. Without using substances comprising any heavy metal element, these fluorescent nanoparticles show very good biocompatibility with cells, thus showing potential applications in cell biolabeling, drug delivery tracing, organic light-emitting diodes, flat displays, and other areas. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Structural diversity of bacterial communities in a heavy metal mineralized granite outcropENVIRONMENTAL MICROBIOLOGY, Issue 3 2006Deirdre Gleeson Summary This laboratory study of a variably mineralized and hydrothermally altered granite outcrop investigated the influences of rock-surface chemistry and heavy metal content on resident bacterial populations. Results indicated that elevated heavy metal concentrations had a profound impact on bacterial community structure, with strong relationships found between certain ribotypes and particular chemical/heavy metal elements. Automated ribosomal intergenic sequence analysis (ARISA) was used to assess the nature and extent of bacterial diversity, and this was combined with chemical analysis and multivariate statistics to identify the main geochemical factors influencing bacterial community structure. A randomization test revealed significant changes in bacterial structure between samples, while canonical correspondence analysis (CCA) related each individual ARISA profile to linear combinations of the chemical variables (mineralogy, major element and heavy metal concentrations) revealing the geochemical factors that correlated with changes in the ARISA data. anova was performed to further explore interactions between individual ribotypes and chemical/heavy metal composition, and revealed that a high proportion of ribotypes correlated significantly with heavy metals. [source] Determinants of urinary 8-hydroxy-2,-deoxyguanosine in Chinese children with acute leukemiaENVIRONMENTAL TOXICOLOGY, Issue 5 2009You Yang Abstract The 8-hydroxy-2,-deoxyguanosine (8-OHdG), an oxidized nucleoside of DNA, not only is a widely used biomarker for the measurement of endogenous oxidative DNA damage, but might also be a risk factor for many diseases including cancer. Elevated level of urinary 8-OHdG has been detected in patients with various malignancies. In the present study, the level of urinary 8-OHdG was examined in 116 Chinese children with acute leukemia (94 acute lymphoid leukemia, ALL, 22 acute myeloid leukemia, AML), and its correlation with urinary metal elements was investigated. Our result showed that the level of urinary 8-OHdG in children with acute leukemia before treatment was significantly elevated compared with that in normal controls (11.92 ± 15.42 vs. 4.03 ± 4.70 ng/mg creatinine, P < 0.05). In particular, urinary 8-OHdG was higher in children with acute leukemia aged under 3 years (20.86 ± 21.75 ng/mg creatinine) than in those aged 3,15 years (8.09 ± 9.65 ng/mg creatinine), whereas no differences were shown in terms of gender, parental smoking and education, household income, place of residence, and use of paracetamol. In addition, urinary 8-OHdG levels were similar among different subtypes of acute lymphoid leukemia (ALL) patients. Furthermore, linear regression analysis revealed a significant correlation between urinary 8-OHdG and urinary Cr, but not Fe or As, in group aged <3 years compared with group aged 3,15 years (P = 0.041), indicating that the metal elements may be involved in increasing urinary 8-OHdG level in younger children with acute leukemia. Our results suggest that children with acute leukemia undergo an increased risk of oxidative DNA damage, which may be correlated with high level of Cr exposure in Chinese children with acute leukemia. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source] Effects of hydrological processes on the chemical composition of riverine suspended sediment in the Zhujiang River, ChinaHYDROLOGICAL PROCESSES, Issue 12 2003Quanzhou Gao Abstract The chemical composition of riverine suspended sediment is the integration of the weathering crust minerals, soil organic matter and erosion agency within a specific drainage basin, which has been largely disturbed by the human activities. Selected metal elements of the riverine suspended sediment in the Zhujiang River were analysed using inductively coupled plasma,atomic emission spectrometry (ICP,AES) in three different hydrological phases from 1997 to 1998 at Makou and Sanshui hydrographic gauge stations, located at the lower reaches of the two main tributaries of the Zhujiang River, i.e. the Xijiang and the Beijing Rivers respectively. Organic carbon and nitrogen were also analysed using a conventional element analyser. The results demonstrate that the chemical composition of the riverine suspended sediment show obvious variability in different hydrological phases, which closely correlate to the organic matter content in suspended sediment. Intensified erosion in the flood phase results in lower concentration of the organic matter than that in the lower water level phase. The riverine suspended sediment with rich organic matter in the lower water level phase adsorbs some metal elements from the river water. Copyright © 2003 John Wiley & Sons, Ltd. [source] Theoretical calculations of transition probabilities and oscillator strengths for Ti III and Ti IVINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 2 2009Tian-Yi Zhang Abstract Due to the complicated electronic configuration of atoms and ions of the transition metal elements, the studies for properties such as transition probabilities and oscillator strengths for these atoms and ions are not systematic. Because of the existence in a variety of stellar objects and wide use in the field of astrophysics, titanium has long been of interest for many researchers. In this article within the Weakest Bound Electron Potential Model (WBEPM) theory, comprehensive set of calculations for transition probabilities and oscillator strengths for Ti III and Ti IV are performed. Many of our results had no previous experimental or theoretical values, so these predictive results could be of some value to the workers in this field. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Transition metal,boron complexes BnM: From bowls (n = 8,14) to tires (n = 14)JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 15 2006Si-Dian Li Abstract Transition metal,boron complexes BnM have been predicted at density functional theory level to be molecular bowls (n = 8,14) hosting a transition metal atom (M) inside or molecular tires (n = 14) centered with a transition metal atom. Small Bn clusters prove to be effective inorganic ligands to all the VB,VIIIB transition metal elements in the periodic table. Density functional evidences obtained in this work strongly suggest that bowl-shaped fullerene analogues of Bn units exist in small BnM complexes and the bowl-to-tire structural transition occur to the first-row transition metal complexes BnM (M = Mn, Fe, Co) at n = 14, a size obviously smaller than n = 20 where the 2D-3D structural transition occurs to bare Bn. The half-sandwich-type B12Cr (C3v), full sandwich-type (B12)2Cr (D3d), bowl-shaped B14Fe (C2), and tire-shaped B14Fe (D7d) and B14Fe, (C7v) are the most interesting prototypes to be targeted in future experiments. These BnM complexes may serve as building blocks to form extended boron-rich BnMm tubes or cages (m , 2) or as structural units to be placed inside carbon nanotubes with suitable diameters. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2006 [source] Microbiological Benefits of Removing Foam Formed After UV-Enhanced Ozonation of Poultry-Processing Chiller Water for RecyclingJOURNAL OF FOOD SCIENCE, Issue 3 2002M.E. Diaz ABSTRACT: Prior experiments using 250 mL samples of unscreened poultry overflow chiller water evaluated the beneficial bactericidal and oxidative effects of 4 different treatments (namely, O2/O3,O2/UV, O2/O3/UV, and O2 as the control) for improving microbiological safety, turbidity, and water-use efficiency allowing its reconditioning for reuse. When excluding foam as in this present study, synergistic reductions > 1.5 log CFU/mL for aerobic plate counts (APC) were additionally achieved after 4 min for all O3/UV treatment combinations as compared to serially applied treatments of O3 and UV acting separately. With foam present, 16-min O3/UV treatments were required to achieve similar results. We now report these additional benefits achieved by removing the foam formed by the advanced oxidation process of ultraviolet-photon enhanced ozonation. Furthermore, foam microbial and general physical content were analyzed to determine suitability as an additive in rendering-type processes. Treatment of the wastewater resulted in total plate counts between 2 to 4 Log CFU/mL in the foam after 8 min. Fat and protein constituted 89% of the solids collected (384 mg/L or 14% of the foam) with trace amounts of metal elements (for example, Ca, Na, K, Fe, Cu) present. Irradiating had negligible effect on foam characteristics yet decreased the amount of solids collected. [source] Biological Cycles of Mineral Elements in a Young Mixed Stand in Abandoned Mining SoilsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2007Da-Lun Tian Abstract Phytoremediation as a sustainable and inexpensive technology based on the removal of pollutants from the environment by plants is becoming an increasingly important objective in plant research. In this study, biological cycles of five nutrient elements (N, P, K, Ca, and Mg) and eight heavy metal elements (Fe, Cu, Zn, Mn, Cd, Ni, Pb and Co) were examined in young paniculed goldraintree (Koelreuteria paniculata Laxm) and common elaeocarpus (Elaeocarpus decipens) mixed stands in an abandoned mining area. We found that after vegetation restoration in abandoned mining areas, the organic matter and concentrations of nutrient elements were significantly increased and the heavy metal elements were significantly decreased, the annual retention, uptake and return were 75.0, 115.4, and 40.3 kg/hm2 for nutrient elements, and 1 878.0, 3 231.0 and 1 353.0 g/hm2 for heavy metal elements, respectively, with the utilization coefficient, cycling coefficient and turnover rate of 0.92, 0.35 and 0.32 for nutrient elements, and 1.24, 0.42 and 1.92 for heavy metal elements, respectively. Our results suggested that the vegetation restoration in abandoned mining areas had significant effects in improving environmental conditions, enhancing soil available nutrients, and ensuring human health. [source] High-Temperature Instability of Li- and Ta-Modified (K,Na)NbO3 PiezoceramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Yongli Wang This paper addresses the high-temperature instability of Li- and Ta-modified (K,Na)NbO3 piezoceramics. The grains with abnormal size evolve out of the fine matrix grains during high-temperature annealing. They are found to be precipitates with a tetragonal tungsten bronze structure, which result from the volatilization and segregation of the alkali metal elements. With the growth of the abnormal grains the composition of the perovskite matrix phase also changes remarkably, as has been suggested by EDX analysis (for Na) and electric measurements (for Li). These variations lead to a large increase in the tetragonal/orthorhombic phase transition temperature and appreciable variations in the dielectric, ferroelectric, and piezoelectric properties of the ceramic samples. Control of the volatilization of the alkali metal elements can efficiently depress the abnormal grain growth and the compositional segregation. [source] Oxygen Effects in Plasma Nitriding of Ferrous AlloysPLASMA PROCESSES AND POLYMERS, Issue S1 2007Carlos A. Figueroa Abstract In this paper, we study the oxygen effect in low energy nitrogen implanted stainless steel AISI 316 at different oxygen partial pressures and temperatures. The samples were studied by photoemission electron spectroscopy (XPS) and sputtered neutral mass spectrometry (SNMS). Increasing the oxygen partial pressure during nitriding decreases the nitrogen content in the material depth. Surface oxidation induces phase segregation. The presence of oxygen forms CrO, on the top most layer of the sample and, subsequently, a nickel layer appears at approximately 9,10 nm beneath the surface. Moreover, the surface oxidation reaction of metal elements depends more strongly on the oxygen atoms landing on the surface rather than on the temperature process. At higher temperatures, on the other hand, the NO, species are degraded. [source] Evaluation of Urinary 8-Hydroxydeoxyguanine inHealthy Japanese PeopleBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2006Shingo Kimura The mean urinary concentration of 8-OHdG was 15.2±5.71 ng/mg creatinine. Mean urinary 8-OHdG was not significantly different in terms of age (<45, ,45), gender, smoking (no, <20, ,20), and alcohol consumption (no, occasionally, sometimes and usually). Moreover, multiple regression analysis showed a significant association between urinary 8-OHdG and urinary arsenic (As) or chromium (Cr), and a tendency for association between the former and aluminum (Al) and nickel (Ni). Age, gender and plasma or serum factors including antioxidants, lipid peroxide, HbA1c, BUN, and iron did not show such an association. The present study suggests that natural exposure to toxic metal elements such as As, Cr, and Ni may influence oxidative DNA damage in healthy people under usual environmental management. Therefore, the measurement of urinary metals such as As, Ni and Cr is prerequisite for the study of the relationship between urinary 8-OHdG and other variable factors. [source] Acid Mine Drainage and Heavy Metal Pollution from Solid Waste in the Tongling Mines, ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2008XU Xiaochun Abstract: Based on investigation of the characteristics of solid waste of two different mines, the Fenghuangshan copper mine and the Xinqiao pyrite mine in Tongling, Anhui province in central-east China, the possibility and the differences of acid mine drainage (AMD) of the tailings and the waste rocks are discussed, and the modes of occurrence of heavy metal elements in the mine solid waste are also studied. The Fenghuangshan copper mine hardly produces AMD, whereas the Xinqiao pyrite mine does and there are also differences in the modes of occurrence of heavy metal elements in the tailings. For the former, toxic heavy metals such as Cu, Pb, Zn, Cd, As and Hg exist mostly in the slag mode, as compared to the latter, where the deoxidization mode has a much higher content, indicating that large amounts minerals in the waste rocks have begun to oxidize at the earth surface. AMD is proved to promote the migration and spread of the heavy metals in mining waste rocks and lead to environmental pollution of the surroundings of the mine area. [source] | |||||||||||||||||||