Search Results (5)

The Mount Weld rare earth element (REE) deposit, Western Australia, is one of the largest of its type on Earth. Current mining exploits the high-grade weathered goethite-bearing resource that lies above, and which represents the weathering product of a subjacent carbonatite. The mineralogy, petrography, deportment of lanthanides among the different components, and variation in mineral speciation, textures, and chemistry are examined. Microanalysis, involving scanning electron microscope (SEM) imaging, electron probe microanalysis (EPMA) and laser ablation inductively coupled-plasma mass spectrometry (LA-ICP-MS), was conducted on sized fractions of three crushed and ground laterite ore samples from current and planned production, and a representative sample from the underlying carbonatite. High-magnification imaging of particles in laterite samples show that individual REE-bearing phases are fine-grained and extend in size well below the micron-scale. Nanoscale inclusions of REE-phosphates are observed in apatite, Fe-(Mn)-(hydr)oxides, and quartz, among others. These have the appearance, particularly in fluorapatite, of pervasive, ultrafine dusty domains. Apart from the discrete REE minerals and abundant nano- to micron-scale inclusions in gangue, all ore components analysed by LA-ICP-MS contain trace to minor levels of REEs within their structures. This includes apatite, where low levels of REE are confirmed in preserved igneous apatite, but also Fe- and Mn-(hydr)oxides in which concentrations of hundreds, even thousands of ppm are measured. This is significant given that Fe-(Mn)-(hydr)oxides are the most abundant component of the laterite and points to extensive mobility and redistribution of REEs, and especially HREE, during progressive lateritisation. Late-formed minerals, notably tiny grains of cerianite, reflect a shift to oxidising conditions. REE-fluorocarbonates are the main host for REEs in carbonatite and are systematically replaced by hydrated, Ca-bearing REE-phosphates (largely rhabdophane). The latter displays varied compositions but is characteristically enriched in HREE relative to monazite in the same sample. Fine-grained, compositionally heterogeneous rhabdophane is accompanied by minor amounts of other paragenetically late, hydrated phosphates with enhanced MREE/HREE relative to LREE (although still LREE-dominant). Minor, relict xenotime and zircon are significant HREE carriers. Ilmenite and pyrochlore group members contain REE but contribute only negligibly to the overall REE budget. Although the proportions of individual mineral species differ, the chemistry of key ore components are similar in different laterite samples from the current resource. Mineral signatures are, however, subtly different in the lower grade southeastern part of the deposit, including higher concentrations of HREE relative to LREE in monazite, rhabdophane, florencite and Fe-(Mn)-(hydr)oxides. Full article

LYN proto-oncogene, Src family tyrosine kinase (Lyn) is a tyrosine kinase that belongs to the Src family (SFK). It is expressed as two isoforms in humans, LynA and LynB. Like other SFKs, Lyn consists of five protein domains, an N-terminal SH4 domain followed by a unique domain, the SH3 and SH2 domains, and a catalytic SH1 domain. The autophosphorylation of Tyr397 activates the protein, while the phosphorylation of the C-terminal inhibitory Tyr508 by C-terminal Src kinase (Csk) or Csk homologous kinase (Chk) inhibits the catalytic activity. The interaction of the SH2 domain with the phosphorylated Tyr508 stabilizes a compact, self-inhibited state. The interaction of the SH3 domain with a linker between the SH2 and catalytic domains further stabilizes this inactive conformation. The two critical structural features of the catalytic domain are a conserved DFG moiety and the αC helix, which can adopt in or out conformations. In the active state, both the DFG moiety and αC helix adopt in conformations, while in the inactive state, they adopt out conformations. Lyn has well-established functions in various hematopoietic cell types and more recent studies have revealed its roles in non-hematopoietic cells. At the molecular level, these functions are mainly exerted by phosphorylating specific tyrosine residues in immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and immunoreceptor tyrosine-based activator motifs (ITAMs) associated with cell surface receptors. The phosphorylation of ITAMs by Lyn can initiate either activating or inhibitory (ITAMi) cell signaling depending on the receptor, targeting mode (crosslinking or monovalent targeting), and the cellular context. The phosphorylation of ITIMs by Lyn initiates inhibitory cell signaling via the recruitment of phosphatases to the ITIM-bearing receptor. The role of Lyn in cancer and autoimmune diseases has been extensively discussed in the literature. The involvement of Lyn in neurodegenerative diseases has been described more recently and, as such, it is now an emerging target for the treatment of neurodegenerative diseases. Full article

The use of rare earth elements in various technologies continues to grow despite some alternatives being found for particular uses. Given a history of ecological concerns about pollution from rare earth mines, particularly in China, there are growing social and environmental concerns about the growth of the mining and mineral processing in this sector. This is best exemplified by the recent social and environmental conflict surrounding the development of the Lynas Advanced Materials Plant (LAMP) in Kuantan, Malaysia which led to international activism and claims of environmental and social injustice. This paper analyses the structure of environmental and social conflicts surrounding rare earth minerals and opportunities for improving the social and environmental performance of the sector. Many of these elements are used for green technologies. Opportunities exist that offer a more circular supply chain following industrial ecological principles through which reuse and recycling of the materials can provide a means of mitigating social and environmental conflicts in this sector. In addition, public engagement processes that recognize community concerns about radiation, and transparent scientifically predicated decision-making through an appropriate governance structure within regulatory organizations are also presented. Full article