天然植物铁芒萁体内稀土元素的分布及其叶绿素镧的结构表征

Ｌａ、Ｃｅ、Ｎｄ、Ｔｂ、Ｄｙ 等稀土元素在铁芒萁（ Ｄｉｃｒａｎｏｐｔｅｒｉｓｄｉｃｈｏｔｏｍａ Ｕｎｄｅｒｗ） 体内的分布规律是叶＞ 根＞ 茎, 而Ｐｒ、Ｓｍ 、Ｅｕ、Ｇｄ、Ｈｏ 和Ｙ等稀土元素在铁芒萁体内的分布规律是根＞ 叶＞ 茎。轻、中稀土元素容易被吸收和积累,并表现出选择性吸收。铁芒萁叶绿素中结合有较多的稀土元素,且主要是轻稀土元素,其中Ｌａ 含量最高,占５６ ．０８％ ,其次是Ｃｅ,占１９ ．４０％ 。利用荧光Ｘ射线吸收精细结构（ＦＸＡＦＳ）光谱表征出,在铁芒萁体内Ｌａ 是与两个卟啉环配位的,推断叶绿素镧为双层结构     

Heteroleptic phthalocyaninato-[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth(III) triple-deckers: synthesis and spectroscopic characterization

The homo-dinuclear heteroleptic phthalocyaninato-[2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyaninato] rare earth(III) triple-decker complexes (Pc)M[Pc(OC₈H₁₇)₈]M[Pc(OC₈H₁₇)₈] (M=Pr, Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm) (1a–10a) and (Pc)M[Pc(OC₈H₁₇)₈]M(Pc) (M=Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm) (2b–10b) were obtained by condensation of bis(phthalocyaninato) rare earths M[Pc(OC₈H₁₇)₈]₂ (M=Pr, Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm), Li₂(Pc) and M(acac)₃·nH₂O (M=Pr, Nd, Sm, Eu, Tb, Dy, Y, Ho, Er, Tm). These novel compounds were characterized by ¹H NMR, mass, electronic absorption (UV–Vis), and IR spectroscopic methods.     

Effects of rare earth elements on telomerase activity and apoptosis of human peripheral blood mononuclear cells

To study the effects of rare earth exposure on human telomerase and apoptosis of mononuclear cells from human peripheral blood (PBMNCs). The blood contents of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y, were measured by inductively coupled plasma-mass spectrometry. Telomeric repeat amplification protocol assay and flow cytometer analysis were carried out to analyze the telomerase activity and apoptosis of PBMNCs, respectively. The total content of rare earth elements in the blood showed significant differences between the exposed group and the control group. The rare earth exposure increased the telomerase activity and the percentages of cells in the S-phase and the G₂/M phase in PBMNCs, but it had no effect on the apoptotic rate of PBMNCs. Under the exposure to lower concentrations of rare earth elements, the telomerase activity of PBMNCs in the exposed group was higher than that of the control group, and there was no effect on the apoptotic rate of PBMNCs, but promoted the diploid DNA replication and increased the percentages of G₂/M- and S-phase cells.     

Criticality of the Rare Earth Elements

Recent constraints on supplies of the rare earth elements (REEs) have led to concerns about their long‐term availability as well as the consequences that shortages would pose for modern technology. To assess this situation, we apply a comprehensive “criticality” methodology to the REE: lanthanum (La); cerium (Ce); praseodymium (Pr); neodymium (Nd); samarium (Sm); europium (Eu); gadolinium (Gd); terbium (Tb); dysprosium (Dy); holmium (Ho); erbium (Er); thulium (Tm); ytterbium (Yb); lutetium (Lu); and yttrium (Y). Assessments are made on national (U.S. and China) and global levels for the year 2008. Evaluations of each indicator are presented and the results plotted in “criticality space” on a 0 to 100 scale. Over the medium term (5 to 10 years), supply risk (SR) for all REEs is moderate with minimal variation (62.8 to 65.1). Over the long term (10 to 100 years), SR is low (42.1 to 49.2). Environmental implications scores, reflecting the economic allocation of environmental burdens, range from 4.2 for La to 34.4 for Lu. Eu, Er, and Dy have the highest vulnerability to supply restriction (VSR) at the global level (50.6, 49.2, and 47.4, respectively), whereas Sm has the lowest (15.1). This is mainly a reflection of their substitution potential. Similarly, at the national level for the United States and China, Eu and Sm have the highest and lowest VSR scores, respectively, although there are notable differences in scores among the REEs and between countries. Although China's export restrictions render REE supplies inadequate to meet demand at present, our analysis indicates a lower criticality for REEs over the longer term than for a number of other industrially used metals.     

Distribution of Rare Earth Elements and Structure Characterization of Chlorophyll-Lanthanum in a Natural Plant Fern Dicranopteris dichotoma

The distribution pattern of La, Ce, Nd, Th, Dy was in the order as leaf > root > stem, that of Pr, Sm, Eu, Cd, Ho, Y was as root > leaf > stem in fern Dicranopteris dichotoma Underw. Light and moderately heavy rare earth elements were easily selectively absorbed and then accumulated by the fern D. dichotoma. Many mainly light rare earth elements are bound to chlorophyll in D. dichotoma. Among the 15 detectable rare earth elements binding to chlorophyll, lanthanum content (50.08 % ) was the highest, and cerium content (19.40%) is the second of all. FXAFS (Fluorescence X-ray absorption fine structure) spectral analysis revealed that lanthanum coordinated 2 porphyrin rings and La-chlorophyll-a may have bilayer structure in D.d/chotoma.     

感耦等离子体发射光谱法研究土壤—铁芒萁系统中稀土元素的分布、累积和迁移特征

用感耦等离子体发射光谱法（ICP－AES）测定了东西赣南地区非稀土矿区和4处不同稀土矿区内,土壤－铁芒萁系统中La、Ce、Pr、Nd、Sm、Gd、Dy、Yb和Y的含量,并对其在土壤剖面层及铁芒萁植物体内的分布、迁移特征进行了研究,结果表明,土训层的底土层含量最高,但表土层铈相对富集、稀土元素总量（∑REE）在铁芒萁植物体内的分布规律是叶＞根＞茎＞叶柄,单一稀土的分布规律各异,La、Ce、Pr、Nd的分布规律表现为：叶＞根＞茎＞叶柄;Sm和Gd在不同采样点表现为叶＞根＞茎＞叶柄或根＞叶＞茎＞叶柄;Dy、Yb和Y均有3种不同的分布模式：叶＞根＞茎＞叶柄、根＞叶＞茎＞叶柄及根＞茎＞叶＞叶柄,稀土元素在铁芒萁体内的迁移过程中,发生了明显的分馏作用,茎、叶柄、叶中的重稀土相对贫乏。     

Dynamic Substance Flow Analysis of Neodymium and Dysprosium Associated with Neodymium Magnets in Japan

Recycling of neodymium and dysprosium is of great interest because of the rapid growth in their demand and limited supply of new resources. To promote recovery from end‐of‐life (EoL) products, it is desirable to quantify the recycling potentials of neodymium and dysprosium by their end use. This study characterized the substance flows of neodymium and dysprosium associated with neodymium magnets in Japan by conducting a dynamic substance flow analysis. A bottom‐up approach was employed in the analysis to estimate annual consumption by end use. Factors used in the analysis were the amounts of rare earth contents, weight of a magnet used for each product, adoption ratios of neodymium magnet usage in each product, and lifetime of products. It was found that the amount of neodymium entering use was approximately half of the domestic consumption; the balance existing in final products that were exported from Japan. The economic feasibility of recycling neodymium magnets was evaluated for their largest two end uses: driving motors in hybrid electric vehicles (HEVs) and compressors in air conditioners. It was found that recycling the neodymium magnets used in the driving motors has the potential for economic feasibility in Japan. The result showed that lower transportation costs for recovered magnets can make the recycling economically feasible regardless of the content rate and the price of metals. The future increase of EoL HEVs contributes to the feasibility of recycling with a profit in the upcoming years. Strategies for more profitable recycling are concentrating scrap motors or magnets among recycling factories or selecting specific factories that deal with EoL HEVs.     

Study on binding of REEs with water-soluble polysaccharides in fern

The binding of rare earth elements (REEs) with water-soluble polysaccharides of nondeproteinization and deproteinization in the leaves of the fernDicranopteris dichotoma was studied by molecular activation analysis (MAA). Two cold-water-soluble polysaccharides (extracted by 75% ethanol and 90% ethanol, respectively) and one hot-water-soluble polysaccharide (extracted by 90% ethanol) were separated using biochemical separation techniques. The eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in these polysaccharides were determined by instrumental neutron activation analysis. Our new results showed that the REEs were bound firmly with the water-soluble polysaccharides in the plant, regardless of whether nondeproteinization or deproteinization was used. The molecular-weight (MW) measurement demonstrated that REEs were mainly bound with low-MW (10,000–20,000) polysaccharides.     

感耦等离子体发射光谱法研究土壤-铁芒萁系统中稀土元素的分布、累积和迁移特征

用感耦等离子体发射光谱法(ICP-AES)测定了江西赣南地区非稀土矿区和处不同稀土矿区内,土壤-铁芒萁系统中La、Ce、Pr、Nd、Sm、Gy、Db、Yb和Y的含量,并对其在土壤剖面层及铁芒萁植物体内的分布、迁移特征进行了研究.结果表明,土壤剖面层的底土层含量最高,但表土层铈相对富集.稀土元素总量(∑REE)在铁芒萁植物体内的分布规律是叶＞根＞茎＞叶柄,单一稀土元素的分布规律各异,La、Ce、Pr、Nd的分布规律表现为:叶＞根＞茎＞叶柄;Sm和Gd在不同采样点表现为叶＞根＞茎＞叶柄或根＞叶＞茎＞叶柄;Dy、Yb和Y均有3种不同的分布模式:叶＞根＞茎＞叶柄、根＞叶＞茎＞叶柄及根＞茎＞叶＞叶柄.稀土元素在铁芒萁体内的迁移过程中,发生了明显的分馏作用,茎、叶柄、叶中的重稀土相对贫乏.     

Rare earth elements in forest-floor herbs as related to soil conditions and mineral nutrition

Mixtures of rare earth elements (REEs) in fertilizers are widely used in Chinese agriculture to improve crop nutrition. REE concentrations in wild-growing plants, especially herbs, are little known. This study describes differences in the concentrations and proportions of REEs in eight forest-floor herbaceous plants and relates these differences to soil and mineral nutrient conditions. REEs studied were yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Leaf concentrations of sum REEs differed more than one order of magnitude between species, being highest in Anemone nemorosa (10.1 nmol/g dry mass) and lowest in Convallaria majalis (0.66 nmol/g) from the same site. Leaf concentrations of all REEs correlated positively (p<0.001), as did sum REE with calcium (Ca) and strontium (Sr) concentrations (p<0.001). A negative relationship (r=−0.83, (p<0.001) was measured between phosphorus (P) concentrations and sum REE concentrations in leaves. However, the proportions of the single REEs in the REE sum differed among species. In A. nemorosa, 57% of the molar REE sum was taken by Y+La, and only 21% by Ce. The other extreme was Maianthemum bifolium, with 37% La+Y and 41% Ce. These two species had 2.7–3.0% of the REE sum as heavier lanthanides, compared to 4.1–5.2% in the six other species. No clear relationship between soil properties or REE contents and leaf REE concentrations was detected. For La, however, an overrepresentation in leaves prevailed throughout all species compared to soils, whereas particularly Nd, Sm, and Tb had a lower proportion in the leaves of all species than in their soils. Possible uptake mechanisms of REEs in plants are discussed.     

Effects of some rare elements on nicotine content of the tobacco plant

Fifty-four rare elements were tested for their effects on the nicotine level of tobacco (Nicotiana tabacum L.) plants grown in solution culture. Be, Cu, Pd, Pt, and Sm definitely increased nicotine yield (over 25%), whereas Bi, Co, Ho, Pb, Ni, Rb, Ag, Tl, Sn, U. V. and Zr definitely decreased nicotine yield. Cs, Er, Li, Rh, Ru, Se, Sr, Ti, and Yb possibly increased (less than 25%) nicotine yield, whereas As, Ce, Cr, Dy, Gd, I, Mo, Nd, Re, Ta, and Th possibly decreased nicotine yield. Other elements including Al, Ge, Au, Hf, In, Ir, La, Lu, Hg, Os, Pr, Sc, Te, Tb, Tm, W, and Zn showed no significant effects.     

Accumulation of rare earth elements in human bone within the lifespan

For the first time, the contents of rare earth elements (REEs) in a rib bone of a healthy human were determined. The mean value of the contents of Ce, Dy, Er, Gd, La, Nd, Pr, Sm, Tb, and Yb (10 elements out of 17 total REEs), as well as the upper limit of means for Ho, Lu, Tm, and Y (4 elements) were measured in the rib bone tissue of 38 females and 42 males (15 to 55 years old) using inductively coupled plasma mass spectrometry (ICP-MS). We found age-related accumulation of REEs in the bone tissue of healthy individuals who lived in a non-industrial region. It was calculated that during a lifespan the content of REEs in a skeleton of non-industrial region residents may increase by one to two orders of magnitude. Using our results as indicative normal values and published data we estimated relative Gd accumulation in the bone tissue of patients according to magnetic resonance imaging with contrast agent and La accumulation in the bone tissue of patients receiving hemodialysis after treatment with lanthanum carbonate as a phosphate binder. It was shown that after such procedures contents of Gd and La in the bone tissue of patients are two to three orders of magnitude higher than normal levels. In our opinion, REEs incorporation may affect bone quality and health similar to other potentially toxic trace metals. The impact of elevated REEs content on bone physiology, biochemistry and morphology requires further investigation.     

Synthesis,density functional theory calculations and luminescence of lanthanide complexes with 2,6‐bis[(3‐methoxybenzylidene)hydrazinocarbonyl] pyridine Schiff base ligand

A pyridine‐diacylhydrazone Schiff base ligand, L = 2,6‐bis[(3‐methoxy benzylidene)hydrazinocarbonyl]pyridine was prepared and characterized by single crystal X‐ray diffraction. Lanthanide complexes, Ln–L, {[LnL(NO₃)₂]NO₃.xH₂O (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Er)} were prepared and characterized by elemental analysis, molar conductance, thermal analysis (TGA/DTGA), mass spectrometry (MS), Fourier transform infra‐red (FT‐IR) and nuclear magnetic resonance (NMR) spectroscopy. Ln–L complexes are isostructural with four binding sites provided by two nitro groups along with four coordination sites for L. Density functional theory (DFT) calculations on L and its cationic [LnL(NO₃)₂]⁺ complexes were carried out at the B3LYP/6–31G(d) level of theory. The FT‐IR vibrational wavenumbers were computed and compared with the experimentally values. The luminescence investigations of L and Ln–L indicated that Tb–L and Eu–L complexes showed the characteristic luminescence of Tb(III) and Eu(III) ions. Ln–L complexes show higher antioxidant activity than the parent L ligand.     

Rare earth elements in soil and plant systems - A review

The rare earth elements (REEs) form a chemically uniform group and include yttrium (Y), lanthanum (La) and the lanthanides cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). Their average abundance in the Earth’s crust range from 66μg g⁻¹ in Ce to 0.5μg g⁻¹ in Tm and ?0.1μg g⁻¹ in Pm. Recent great improvements in more routine analytical technique, the use of REEs as fertilisers, at least in East Asian agriculture, and the importance of these elements as indicators in both pedological and physiological processes and reactions have contributed to an increased interest in these previously less considered elements in environmental sciences. This review of recent and current literature deals with REEs in primary and secondary soil minerals, concentrations in surface soils, factors influencing adsorption, solubility and transport in soils, including weathering and transformations of REE minerals, and vertical distribution in soil profiles. Reviewed and discussed are also concentrations, distribution and localisation of REEs in plants and plant organs, soil-plant relationships and interactions, effects on plant growth and crop production and their importance in plant physiology and biochemistry. The REEs are found, usually several elements together, as phosphates, carbonates and silicate minerals finely dispersed especially in magmatic and metamorphic rocks. REE concentrations in surface soils of humid climates, such as the A(E)-horizons of Podzols and Laterites, are usually lower than in the parent material, due to higher weathering and leaching rates than of the average soil constituents. Some fractionation may occur due to the formation of more element-specific secondary minerals. Transfer from soil to plant is usually low, but extreme accumulators are found, e.g., among several species of ferns. Roots have generally higher concentrations than shoots. Possible uptakemechanisms of REEs are discussed. Uptake is positively, though often weakly, correlated with soil acidity and easily soluble concentrations of the elements, but rarely well related to their total concentrations in the soil. Under certain conditions, low concentrations of at least some REEs seem to favour plant growth and productivity, but the physiological mechanisms are still not well understood. Some considerations concerning the boundary between essential and non-essential micro nutrients are discussed.     

Effects of rare earth elements on the growth of Cistanche deserticola cells and the production of phenylethanoid glycosides

The rare earth elements Nd, La, Ce at proper concentrations had positive effects on the cell growth of Cistanche deserticola and production of phenylethanoid glycosides (PeG). A mixture of rare earth elements (MRE, La(2)O(3):CeO(2):Pr(6)O(11):Sm(2)O(3)=255:175:3:1, mol/mol) showed the most remarkable effects. After 30 day's culture, 0.02 mmoll(-1) MRE gave the highest content (20.8%) and production (1.6 gl(-1)) of PeG, which were 104 and 167% higher than those obtained in control (without rare earth elements).     

Coordination polymers of Ln(III): Synthesis, characterization, catalytic and antimicrobial aspects

Coordination polymers of HEAP-ED with La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III) and Dy(III) metal ions have been synthesized and characterized by elemental analyses, electronic spectra, magnetic susceptibilities, FTIR, NMR, scanning electronic microscopy (SEM) and thermogravimetric analyses. Catalytic activity of selected coordination polymers was examined for pharmaceutical important organic synthesis. Antimicrobial activity of isolated Ln(III) coordination polymers against Escherichia coli, Bacillus subtilis, Staphylococcus aureus (bacteria) and Saccharomyces cerevisiae (yeast) were measured. It was observed from the study that the Ln(III) coordination polymers acted as an efficient and effective catalysts and antimicrobial agents.     

Effects of rare earth ions (Tb,Ce, Eu,Dy) on the thermoluminescence characteristics of sol–gel derived and γ‐irradiated SiO2 nanoparticles

Highly pure SiO₂ and SiO₂:RE nanoparticles were synthesized by the sol–gel method. The morphological, structural and optical properties of the nanoparticles were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results indicate that all the samples studied were free from impurities. SEM/TEM results indicate that the samples were well dispersed. Surface characterization of the nanocrystals by Fourier transform infrared spectroscopy has been carried out and the structure of surface‐bound SiO₂ based on spectral analysis is proposed. Thermoluminescence (TL) characteristics were investigated to study the influence of rare earth dopants (Tb, Ce, Eu, Dy) on SiO₂ matrix subjected to 0.5 kG (1 h) γ‐irradiation. Among these rare earth elements, Eu³⁺ was found to be the most efficient dopant for SiO₂ showing maximum thermoluminescence intensity. SiO₂:Eu_0.5 seems to be a promising candidate for use as a TL dosimeter. Copyright © 2013 John Wiley & Sons, Ltd.     

Nature and composition of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Dy(III) and Ho(III) complexes of embelin

The isolation and characterization of nine polymeric complexes of the general formula [M(L)_1.5S₂]_n (where M is the metal ion, L the ligand and S the solvent, C₂H₅OH) of La(III) and Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) with.the biologically active compound embelin using elemental and thermal analysis, infrared and electronic spectral studies is reported.     

A Regularity of the Liquid-Liquid Partition Coefficients of Tris(acetylacetonato) Rare Earth(III) Chelates

The extraction of La(III), Nd(III), Sm(III), Tb(III) and Lu(III) with acetylacetone in benzene has been studied. The partition coefficients of these tris- (acetylacetonato) rare earth(III) chelates do not show the same value but increase as the atomic number of rare earth increases. From comparison of the experimental partition coefficient with the theoretical partition coefficient for the tris-acetylacetonato metal(III) chelate estimated from the regular solution concept and the cavity formation energy, this tendency is ascribed to the gradual decrease of the hydration of the neutral chelate in the aqueous phase.     

Mapping first to final uses for rare earth elements,globally and in the United States

Estimating the material flows of rare earth elements (REEs) is essential to understanding which industries are most vulnerable to potential REE supply disruptions which, in turn, may inform policy recommendations aimed at reducing the supply risk. However, the REEs are a group of mineral commodities characterized by highly uncertain estimates of supply and demand due to the REE market's complexity, opacity, and small size. In this study, a streamlined methodology was applied to map mineral commodity first-use to final-use applications and to estimate total requirements at the national level based on available industrial data for final-use finished goods. This analysis examines REEs both as a group and individually, showing that total US requirements are between 15% and 16.5% of world requirements for the year 2015, the latest year with the most complete information available. The findings shed light on US industrial capabilities by revealing the discrepancy between the types of REEs that go into US raw material consumption and those that are contained in embedded consumption. For instance, given the United States’ large oil refining industry, US raw material consumption of lanthanum is quite high. In contrast, US raw material consumption of neodymium is relatively low, whereas embedded demand is comparatively high. This reflects the lack of industrial capacity to process REE concentrates into magnet material combined with the US's high imports of products that contain rare earth permanent magnets.