Due to their good properties of elastic modulus, degradability and ability to promote bone repair, magnesium alloys have become a research hotspot in research of orthopedic implants. Nevertheless, most of the biomedical magnesium alloys currently available fail to meet the requirements in orthopedics because of their rapid degradation after implantation. Rare earth-magnesium alloys possess excellent corrosion resistance and are expected to become important materials as clinical orthopedic implants. This review summarizes the recent progress in studies of the physiological functions of rare earth elements, the effects of supplementation of rare earth elements on biomechanical properties and the in vitro and in vivo biocompatibility of magnesium alloys, and their contribution to tendon-bone healing, addressing also the current clinical orthopedic applications of different rare earth-magnesium alloys, challenges, and future strategies for improving these alloys.
Alloys/chemistry* ; Magnesium/chemistry* ; Metals, Rare Earth/chemistry* ; Humans ; Biocompatible Materials ; Prostheses and Implants

OBJECTIVE: To investigate the rare earth elements(REEs) contents and distribution characteristics in nasopharyngeal carcinoma( NPC) tissue in Gannan region. METHOD: Thirty patients of NPC in Gannan region were included in this study. The REEs contents were measured by tandem mass spectrometer inductively coupled plasma(ICP-MS/MS) in 30 patients, and the REEs contents and distribution were analyzed. RESULT: The average standard deviation value of REEs in lung cancer and normal lung tissues was the minimum mostly. Light REEs content was higher than the medium REEs, and medium REEs content was higher than the heavy REEs content. REEs contents changes in nasopharyngeal carcinoma were variable obviously, the absolute value of Nd, Ce, Pr, Gd and other light rare earth elements were variable widely. The degree of changes on Yb, Tb, Ho and other heavy rare earth elements were variable widely, and there was presence of Eu, Ce negative anomaly(δEu=0. 385 5, δCe= 0. 523 4). CONCLUSION The distribution characteristic of REEs contents in NPC patients is consistent with the parity distribution. With increasing atomic sequence, the content is decline wavy. Their distribution patterns were a lack of heavy REEs and enrichment of light REEs, and there was Eu , Ce negative anomaly.
Carcinoma ; Humans ; Lung ; Lung Neoplasms ; Metals, Rare Earth ; chemistry ; Nasopharyngeal Carcinoma ; Nasopharyngeal Neoplasms ; chemistry ; Reference Values ; Tandem Mass Spectrometry

OBJECTIVEThe aim of this survey was to investigate the level of contamination of the most consumed foods in China with 16 rare earth elements (REEs), and to provide the basic data for establishing and revising food safety standards for REEs.

METHODSSixteen REEs in foods were measured by inductively coupled plasma-mass spectrometry (ICP-MS) in the labs of the Centers for Disease Control and Prevention of four provinces and two municipalities, during 2009-2010.

RESULTS1 231 samples were analyzed and 19 121 concentration data of 16 REEs were collected. The REEs levels in the investigated foods varied significantly. The concentrations of cerium (Ce), dysprosium (Dy), yttrium (Y), lanthanum (La), and neodymium (Nd) were relatively high, while the remaining eleven REEs were at low levels. The mean values of total rare earth element oxides (REOs) in cereals, fresh vegetables, fresh aquatic products, fresh meats and eggs varied from 0.052 mg/kg to 0.337 mg/kg.

CONCLUSION16 REEs in the major foods were at very low contamination levels in the investigated regions.

Animals ; China ; Edible Grain ; chemistry ; Eggs ; Fishes ; Food Analysis ; Food Contamination ; Meat ; analysis ; Metals, Rare Earth ; chemistry ; Mollusca ; Swine ; Vegetables ; chemistry

The process in the studies on physiological effects of rare earth elements in plants and their action mechanisms were summarized in the aspects of seed germination, photosynthesis, mineral metabolism and stress resistance. And the applications of rare earth elements in traditional Chinese medicine (TCM) in recent years were also overviewed, which will provide reference for further development and application of rare earth elements in TCM.
Medicine, Chinese Traditional ; Metals, Rare Earth ; analysis ; metabolism ; Photosynthesis ; Plants, Medicinal ; chemistry ; growth & development ; metabolism ; Soil ; analysis

OBJECTIVETo study the effects of aluminum citrate (AC), rare earth compounds (REC) and sodium selenite (SS) on the surface elements of chrysotile fibers and the inhibitory mechanisms of three compounds for chrysotile-induced biological activities.

METHODSAfter being soaked in 250, 500 and 1000 microg/ml aluminum citrate solutions, 125, 250, 500 and 1000 microg/ml mixed rare earths solutions or 125, 250, 500 and 1000 microg/ml sodium selenite solutions for 10 min or 1 hour, the fabrication and the levels of surface elements of chrysotile fibers were determined.

RESULTSAluminum citrate, mixed rare earths or sodium selenite all could be adsorbed by chrysotile fibers. After pretreatment of chrysotile fibers with aluminum citrate, mixed rare earths or sodium selenite solutions for 10 min or 1 hour, the corresponding elements or ion on the surface of chrysotile fibers increased with the increase of concentration of the solutions.

CONCLUSIONPretreatment of chrysotile with aluminum citrate, mixed rare earths or sodium selenite solutions can change the fabrication and the levels of surface elements of chrysotile fibers, and inhibit the biological activities of chrysotile by "sealing" some "active sites" on the surface of chrysotile fibers.

Asbestos, Serpentine ; chemistry ; toxicity ; Citric Acid ; chemistry ; Metals, Rare Earth ; chemistry ; Sodium Selenite ; chemistry

OBJECTIVETo evaluate the colouration of zirconia ceramic by adding three kinds of rare earth oxides. The influence of the pigments concentration on the mechanical properties and the microstructure was also analyzed.

METHODSAdded different concentrations of CeO(2), Er(2)O(3) and Pr(6)O(11) in tetragonal zirconia poly crystals stabilized with 3 mol% yttria (3Y-T2P) powder, compacted at 200 MPa using cold isostatic pressure, and sintered to 1 400 degrees C. The heating rate was 150 degrees C/h and the dwelling time was 2 hours. The chromaticity of sintered bodies was measured with chroma meter. The relative density, hardness, flexure strength and fracture toughness were investigated as well. The phase stability of the colorized and pure zirconia was evaluated by X-ray diffraction (XRD) using an automated diffractometer. The microstructures of the specimens were evaluated by scanning electron microscope (SEM).

RESULTSSeveral kinds of color achieved by the different pigments praseodym oxide, cerium oxide and erbium oxide were presented in the CIELab system. The a* value increased with the added amount of Er(2)O(3), while b* value rose with the increasing amount of CeO(2) and Pr(6)O(11). However, three pigments failed to decrease L* value and the sintered body appeared too bright. Adding three pigments influenced flexure strength of zirconia ceramic significantly, but had little influence on the hardness and fracture toughness. Microscopy revealed the relationship between the porosity and shapes of grains was correlated to strength of the diphase ceramics. No additional phase could be detected by XRD, except t-ZrO(2) in all colorized samples after sintering at 1 400 degrees C for 120 min.

CONCLUSIONSZirconia ceramic can be colorized by CeO(2), Er(2)O(3), and Pr(6)O(11). Pigments even in a small amount influence the mechanical properties of the colorized zirconia material, which necessitates further investigation.

Coloring Agents ; pharmacology ; Dental Porcelain ; chemistry ; Dental Stress Analysis ; Metals, Rare Earth ; pharmacology ; Oxides ; pharmacology ; Prosthesis Coloring ; Zirconium ; chemistry

OBJECTIVETo study the relationship of hair content of rare earth elements (REEs) in the young children aged 0 - 3 years to that in their mothers living in a rare earth mining area of Jiangxi Province.

METHODSContent of five kinds of REEs, i.e., lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd) and samarium (Sm) were determined for the hair-root samples collected from 71 young children and 62 of their mothers by inductively coupled plasma source mass spectrometry (ICP-MS).

RESULTSThe mean hair content of REEs (e.g., La) was the highest (2,202.90 ng/g) in the young children living in the place nearest to the REE mining area, next (471.72 ng/g) was in those nearer to the REE mining area, and the lowest (97.37 ng/g) was in those in the control area. And, the hair content of REEs in the mothers was the same as that in their children, i.e, the mean content of La was the highest (1,510.21 ng/g) in high-exposure area, next (241.63 ng/g) was that in the low-exposure area, and the lowest (59.15 ng/g) was that in the control area, with P < 0.001. Pair-comparison analysis for the means showed that the average hair level of five kinds of REEs in the young children was two times high as their mothers' (P < 0.001). For example, the hair level of La was 533.83 ng/g in the young children and 279.78 ng/g in their mothers, respectively. Simple linear regression analysis showed that there was a significant correlation between the hair levels of each kind of REEs in the young children and those in their mothers, with a correlation coefficient of more than 0.75, e.g., that of La was 0.878 (P < 0.01).

CONCLUSIONSThe hair level of REEs can be used as a bio-marker to reflect body's level of exposure to REEs. The hair level of REEs in young children and their mothers decreased with the increase of the distance from their home to rare earth mining area. Young children living in the area with REEs mining may be the high-exposure population, and their hair level of REEs was significantly higher than that in their mothers and more attention should be paid to them.

Child, Preschool ; Environmental Exposure ; Hair ; chemistry ; Humans ; Infant ; Infant, Newborn ; Metals, Rare Earth ; analysis ; Mining ; Mothers