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Yuanxing Dong

Bio: Yuanxing Dong is an academic researcher from Xizhou Teachers University. The author has contributed to research in topics: Carbon fibers & Materials science. The author has an hindex of 3, co-authored 3 publications receiving 97 citations.

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Journal ArticleDOI
TL;DR: Results show that Se at higher exposure levels would significantly inhibit the absorption and transportation of Hg when Hg(2+) levels are higher than 1mg/L in culture media, and elemental imaging using μ-SRXRF shows that Se could inhibit the accumulation and translocation of HG in garlic.

70 citations

Journal ArticleDOI
TL;DR: Hg-mediated changes in Se species along with reduced Se accumulation in garlic may account for the protective effect of Hg against Se phytotoxicity.
Abstract: Combined pollution of selenium (Se) and mercury (Hg) has been known in Wanshan district (Guizhou Province, China). A better understanding of how Se and Hg interact in plants and the phytotoxicity thereof will provide clues about how to avoid or mitigate adverse effects of Se/Hg on local agriculture. In this study, the biological activity of Se has been investigated in garlic with or without Hg exposure. Se alone can promote garlic growth at low levels ( 1 mg L(-1)). The promotive effect of Se in garlic can be enhanced by low Hg exposure (<0.1 mg L(-1)). When both Se and Hg are at high levels, there is a general antagonistic effect between these two elements in terms of phytotoxicity. Inductively coupled plasma mass spectrometry (ICP-MS) data suggest that Se is mainly concentrated in garlic roots, compared to the leaves and the bulbs. Se uptake by garlic in low Se medium (<0.1 mg L(-1)) can be significantly enhanced as Hg exposure levels increase (P < 0.05), while it can be inhibited by Hg when Se exposure levels exceed 1 mg L(-1). The synchrotron radiation X-ray fluorescence (SRXRF) mapping further shows that Se is mainly concentrated in the stele of the roots, bulbs and the veins of the leaves, and Se accumulation in garlic can be reduced by Hg. The X-ray absorption near edge structure (XANES) study indicates that Se is mainly formed in C-Se-C form in garlic. Hg can decrease the content of inorganic Se mainly in SeO3(2-) form in garlic while increasing the content of organic Se mainly in C-Se-C form (MeSeCys and its derivatives). Hg-mediated changes in Se species along with reduced Se accumulation in garlic may account for the protective effect of Hg against Se phytotoxicity.

29 citations

Journal ArticleDOI
TL;DR: In this paper, a procedure was proposed for quantification of Fe, Cu and Zn in protein bands using synchrotron radiation X-ray fluorescence (SRXRF) after isoelectric focusing (IEF).

6 citations

Journal ArticleDOI
TL;DR: In this paper , an MHDCFC with fuel continuously supplied is proposed and anode structural parameters are optimized through a computational fluid dynamics (CFD) model and a current model.

Cited by
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Journal ArticleDOI
TL;DR: X-ray fluorescence imaging is a powerful technique that can be used to determine elemental and chemical species distributions at a range of spatial resolutions within samples of biological tissues, and the technique is capable of determining metal and nonmetal distributions on a variety of length scales.
Abstract: From the perspective of a chemist, biology confers a rich variety of roles on a number of metal ions. It is widely agreed that a large fraction of the genomic output of living things contains metal or metalloid ions, although estimates of this fraction vary widely and depend upon which metal ions are considered.1−3 Moreover, recent reports suggest that, at least in some cases, there are many uncharacterized metalloproteins.4 With inclusion of the s-block metals such as Na, K, Mg, and Ca, the proportion likely approaches 100%; recent estimates from the protein data bank indicate that the prevalence of heavier metal ions of atomic number above 20 within proteins is around 22%,5 with Zn2+ proteins alone constituting about 11%. Living organisms have an inherent and very rich physical structure, with relevant length scales ranging from the nanometer scale for subcellular structure to hundreds of micrometers and above for tissue, organ, or organism-level organization. The ability to derive the spatial distribution of elements on this diversity of length scales is a key to understanding their function. Metals play essential and central roles in the most important and chemically challenging processes required for life, with active site structures and mechanisms that, at the time of their discovery, have usually not yet been duplicated in the chemical laboratory. Furthermore, diseases of metal dysregulation can cause disruption in the distribution of metals.6 For example, Menke’s disease and Occipital Horn Syndrome,7 and Wilson’s disease,8 involve disruption in copper uptake and excretion, respectively, through mutation in the ATP7A and ATP7B Cu transporters.9 The mechanisms of action of toxic elements such as mercury and arsenic are also of interest, as are essential nonmetal trace elements, such as selenium. Likewise, an increasing number of pharmaceuticals include metals or heavier elements; such chemotherapeutic drugs include the platinum derivatives cisplatin and carboplatin,10 some promising new ruthenium drugs,11 and arsenic trioxide, which has been used to treat promyelocytic leukemia.12 Understanding the localization, speciation, and distribution of these at various length scales is of significant interest. A wide variety of heavier elements can be probed by X-ray spectroscopic methods; these are shown graphically in Figure ​Figure1.1. X-ray fluorescence imaging is a powerful technique that can be used to determine elemental and chemical species distributions at a range of spatial resolutions within samples of biological tissues. Most modern applications require the use of synchrotron radiation as a tunable and high spectral brightness source of X-rays. The method uses a microfocused X-ray beam to excite X-ray fluorescence from specific elements within a sample. Because the method depends upon atomic physics, it is highly specific and enables a wide range of chemical elements to be investigated. A significant advantage over more conventional methods is the ability to measure intact biological samples without significant treatment with exogenous reagents. The technique is capable of determining metal and nonmetal distributions on a variety of length scales, with information on chemical speciation also potentially available. Figure ​Figure22 shows examples of rapid-scan X-ray fluorescence imaging at two contrasting length scales: rapid-scan imaging13 of a section of a human brain taken from an individual suffering from multiple sclerosis and showing elemental profiles for Fe, Cu, and Zn;14 and a high-resolution image showing mercury and other elements in a section of retina from a zebrafish larva treated with methylmercury chloride.15 We will discuss both the state of the art in terms of experimental methods and some recent applications of the methods. This Review considers X-ray fluorescence imaging with incident X-ray energies in the hard X-ray regime, which we define as 2 keV and above. We review technologies for producing microfocused X-ray beams and for detecting X-ray fluorescence, as well as methods that confer chemical selectivity or three-dimensional visualization. We discuss applications in key areas with a view to providing examples of how the technique can provide information on biological systems. We also discuss synergy with other methods, which have overlapping or complementary capabilities. Our goal is to provide useful and pertinent information to encourage and enable further use of this powerful method in chemical and biochemical studies of living organisms. Figure 1 Periodic table of the elements showing elements of biological interest that can be probed using X-ray fluorescence imaging. Elements are divided into three categories, those that are physiologically important, those that are pharmacologically active, ...

245 citations

Journal ArticleDOI
TL;DR: The natural and anthropogenic sources that have contributed to the increase of Hg concentration in soil are summarized and major remediation techniques and their applications to control soil Hg contamination are reviewed.

194 citations

Journal ArticleDOI
TL;DR: A plausible link among Hg levels, its chemical speciation and phytoavailability in soil, accumulation in plants, phytotoxicity and detoxification of Hg inside the plant is traced and well summarized and up-to-date data are described.

149 citations

Journal ArticleDOI
TL;DR: Biofortification of some crops with Se using agronomic and genetic approaches is being explored to cultivate them in the regions having Se-deficiency in foods.
Abstract: Selenium (Se) is an essential nutrient for animals, humans, and microorganisms, but its role in the plants needs further exploration. It is considered beneficial at low levels, but is toxic at higher levels, and there is a fine boundary between these concentrations. Generally, Se levels less than 1 mg kg−1 have been found to be beneficial for the plants while higher levels cause toxicity in most of the agricultural crops. At low concentrations, Se can act as a plant growth regulator, antioxidant, anti-senescent, abiotic stress modulator, and defensive molecule against pathogens in plants. At higher concentrations, plants show various toxic symptoms, which include stunting of growth, chlorosis, withering, and drying of leaves, decreased protein synthesis premature and even death of the plant. The roles of selenium as enhancer and inhibitor of plant growth in various agricultural crops are discussed here with recent updates. Biofortification of some crops with Se using agronomic and genetic approaches is be...

117 citations

Book ChapterDOI
01 Jan 2017
TL;DR: This chapter aims to compile some information about research work on essentiality of Se for humans and other mammals, and the need for a sufficient daily Se intake.
Abstract: Selenium (Se) is an essential micronutrient for human and animal healthy due to its capabilities to support antioxidant defence systems. However, problems related to the deficiency of Se are emerging issue for human health worldwide and plant species differ considerably in their susceptibility to high concentrations of Se, and certain plant species can be able to accumulate Se to astonishingly high concentrations. Many factors can affect the content of Se in different foods, including different uptake rate by plants, which can be related to plant type, soil, pH, microbial activity, rainfall and a number of other biogeochemical parameters. Humans Se intake and Se status in the population depends firstly on Se concentrations in soils, and hence the Se concentrations in the harvested edible plants in these soils. Thus, this chapter aims to compile some information about research work on essentiality of Se for humans and other mammals, and the need for a sufficient daily Se intake.

92 citations