Hydrothermal alteration of eudialyte-hosted critical metal deposits : fluid source and implications for deposit grade

MV, AB and AF were funded by the NERC-funded SOS RARE consortium, grant number NE/M010856/1.Eudialyte-hosted critical metal deposits potentially represent major sources of rare earth elements (REE), zirconium and niobium. Here, we study the chemical and isotopic composition of fresh and altered eudialyte in nepheline syenite from the Ilímaussaq Complex, Greenland, one of the world’s largest known eudialyte-hosted deposits. Late-magmatic hydrothermal alteration caused partial replacement of primary magmatic eudialyte by complex pseudomorph assemblages of secondary Zr-, Nb-, and REE-minerals. Three secondary assemblage types are characterised by the zirconosilicates catapleiite, gittinsite and zircon, respectively, of which the catapleiite type is most common. To investigate elemental exchange associated with alteration and to constrain the nature of the metasomatic fluids, we compare trace elements and Sm/Nd isotope compositions of unaltered eudialyte crystals and their replaced counterparts from five syenite samples (three catapleiite-type, one gittinsite-type, and one zircon-type assemblage). Trace element budgets for the catapleiite-type pseudomorphs indicate a 15–30% loss of REE, Ta, Nb, Zr, Sr and Y relative to fresh eudialyte. Moreover, the gittinsite- and zircon-type assemblages record preferential heavy REE (HREE) depletion (≤50%), suggesting that the metasomatic fluids mobilised high field strength elements. Initial Nd isotope ratios of unaltered eudialyte and catapleiite- and gittinsite-type pseudomorphs are indistinguishable, confirming a magmatic fluid origin. However, a higher initial ratio and stronger HREE depletion in the zircon-type pseudomorphs suggests a different source for the zircon-forming fluid. Although alteration reduces the metal budget of the original eudialyte volume, we infer that these elements re-precipitate nearby in the same rock. Alteration, therefore, might have little effect on overall grade but preferentially separates heavy and light REE into different phases. Targeted processing of the alteration products may access individual rare earth families (heavy vs. light) and other metals (Zr, Nb, Ta) more effectively than processing the fresh rock.Publisher PDFPeer reviewe

Hydrothermal Alteration of Eudialyte-Hosted Critical Metal Deposits: Fluid Source and Implications for Deposit Grade

Eudialyte-hosted critical metal deposits potentially represent major sources of rare earth elements (REE), zirconium and niobium. Here, we study the chemical and isotopic composition of fresh and altered eudialyte in nepheline syenite from the Ilímaussaq Complex, Greenland, one of the world’s largest known eudialyte-hosted deposits. Late-magmatic hydrothermal alteration caused partial replacement of primary magmatic eudialyte by complex pseudomorph assemblages of secondary Zr-, Nb-, and REE-minerals. Three secondary assemblage types are characterised by the zirconosilicates catapleiite, gittinsite and zircon, respectively, of which the catapleiite type is most common. To investigate elemental exchange associated with alteration and to constrain the nature of the metasomatic fluids, we compare trace elements and Sm/Nd isotope compositions of unaltered eudialyte crystals and their replaced counterparts from five syenite samples (three catapleiite-type, one gittinsite-type, and one zircon-type assemblage). Trace element budgets for the catapleiite-type pseudomorphs indicate a 15–30% loss of REE, Ta, Nb, Zr, Sr and Y relative to fresh eudialyte. Moreover, the gittinsite- and zircon-type assemblages record preferential heavy REE (HREE) depletion (≤50%), suggesting that the metasomatic fluids mobilised high field strength elements. Initial Nd isotope ratios of unaltered eudialyte and catapleiite- and gittinsite-type pseudomorphs are indistinguishable, confirming a magmatic fluid origin. However, a higher initial ratio and stronger HREE depletion in the zircon-type pseudomorphs suggests a different source for the zircon-forming fluid. Although alteration reduces the metal budget of the original eudialyte volume, we infer that these elements re-precipitate nearby in the same rock. Alteration, therefore, might have little effect on overall grade but preferentially separates heavy and light REE into different phases. Targeted processing of the alteration products may access individual rare earth families (heavy vs. light) and other metals (Zr, Nb, Ta) more effectively than processing the fresh rock

Hepatotoxicity Screening on In Vitro Models and the Role of 'Omics

The liver is one of the five most common target organs of toxicity, both during acute and chronic (repeated dose) toxicity, not only for drugs but also for cosmetic ingredients. Chemical entities can trigger liver damage in humans, and hepatotoxicity is the leading cause of withdrawal of drugs from the market, accounting for 40% of withdrawals worldwide. It has been estimated that only 50% of human liver toxicities could be predicted using animal models, and there is a clear need for accurately predictive toxicity and safety testing methods. Hepatocellular injury can manifest in a number of ways, including hepatitis, steatosis, cirrhosis, inflammation, phospholipidosis, and cholestasis. Cholestasis and steatosis are among the most prominent and well-documented types of liver injury and are the focus of this chapter. Furthermore, attention is also paid to necrosis, a mode of cell death that is observed in most of the aforementioned types of hepatocellular injury

Hepatotoxicity Screening on In Vitro Models and the Role of 'Omics

The liver is one of the five most common target organs of toxicity, both during acute and chronic (repeated dose) toxicity, not only for drugs but also for cosmetic ingredients. Chemical entities can trigger liver damage in humans, and hepatotoxicity is the leading cause of withdrawal of drugs from the market, accounting for 40% of withdrawals worldwide. It has been estimated that only 50% of human liver toxicities could be predicted using animal models, and there is a clear need for accurately predictive toxicity and safety testing methods. Hepatocellular injury can manifest in a number of ways, including hepatitis, steatosis, cirrhosis, inflammation, phospholipidosis, and cholestasis. Cholestasis and steatosis are among the most prominent and well-documented types of liver injury and are the focus of this chapter. Furthermore, attention is also paid to necrosis, a mode of cell death that is observed in most of the aforementioned types of hepatocellular injury.</p

Safety and Feasibility of Additional Tumor Debulking to First-Line Palliative Combination Chemotherapy for Patients with Multiorgan Metastatic Colorectal Cancer

INTRODUCTION: Local treatment of metastases is frequently performed in patients with multiorgan metastatic colorectal carcinoma (mCRC) analogous to selected patients with oligometastatic disease for whom this is standard of care. The ORCHESTRA trial (NCT01792934) was designed to prospectively evaluate overall survival benefit from tumor debulking in addition to chemotherapy in patients with multiorgan mCRC. Here, we report the preplanned safety and feasibility evaluation after inclusion of the first 100 patients. METHODS: Patients were eligible if at least 80% tumor debulking was deemed feasible by resection, radiotherapy and/or thermal ablative therapy. In case of clinical benefit after three or four cycles of respectively 5-fluorouracil/leucovorin or capecitabine and oxaliplatin ± bevacizumab patients were randomized to tumor debulking followed by chemotherapy in the intervention arm, or standard treatment with chemotherapy. RESULTS: Twelve patients dropped out prior to randomization for various reasons. Eighty-eight patients were randomized to the standard (n = 43) or intervention arm (n = 45). No patients withdrew after randomization. Debulking was performed in 82% (n = 37). Two patients had no lesions left to treat, five had progressive disease, and one patient died prior to local treatment. In 15 patients (40%) 21 serious adverse events related to debulking were reported. Postoperative mortality was 2.7% (n = 1). After debulking chemotherapy was resumed in 89% of patients. CONCLUSION: Tumor debulking is feasible and does not prohibit administration of palliative chemotherapy in the majority of patients with multiorgan mCRC, despite the occurrence of serious adverse events related to local treatment. IMPLICATIONS FOR PRACTICE: This first prospective randomized trial on tumor debulking in addition to chemotherapy shows that local treatment of metastases is feasible in patients with multiorgan metastatic colorectal cancer and does not prohibit administration of palliative systemic therapy, despite the occurrence of serious adverse events related to local treatment. The trial continues accrual, and overall survival (OS) data and quality of life assessment are collected to determine whether the primary aim of >6 months OS benefit with preserved quality of life will be met. This will support evidence-based decision making in multidisciplinary colorectal cancer care and can be readily implemented in daily practice

Data from: Estimating the reproducibility of psychological science

This record contains the underlying research data for the publication "Estimating the reproducibility of psychological science" and the full-text is available from: https://ink.library.smu.edu.sg/lkcsb_research/5257Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. We conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. Replication effects were half the magnitude of original effects, representing a substantial decline. Ninety-seven percent of original studies had statistically significant results. Thirty-six percent of replications had statistically significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 39% of effects were subjectively rated to have replicated the original result; and if no bias in original results is assumed, combining original and replication results left 68% with statistically significant effects. Correlational tests suggest that replication success was better predicted by the strength of original evidence than by characteristics of the original and replication teams