68 research outputs found

    Fractionation of Li, Be, Ga, Nb, Ta, In, Sn, Sb, W and Bi in the peraluminous Early Permian Variscan granites of the Cornubian Batholith: precursor processes to magmatic-hydrothermal mineralisation

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    The Early Permian Variscan Cornubian Batholith is a peraluminous, composite pluton intruded into Devonian and Carboniferous metamorphosed sedimentary and volcanic rocks. Within the batholith there are: G1 (two-mica), G2 (muscovite), G3 (biotite), G4 (tourmaline) and G5 (topaz) granites. G1-G2 and G3-G4 are derived from greywacke sources and linked through fractionation of assemblages dominated by feldspars and biotite, with minor mantle involvement in G3. G5 formed though flux-induced biotite-dominate melting in the lower crust during granulite facies metamorphism. Fractionation enriched G2 granites in Li (average 315 ppm), Be (12 ppm), Ta (4.4 ppm), In (74 ppb), Sn (18 ppm) and W (12 ppm) relative to crustal abundances and G1 granites. Gallium (24 ppm), Nb (16 ppm) and Bi (0.46 ppm) are not significantly enriched during fractionation, implying they are more compatible in the fractionating assemblage. Sb (0.16 ppm) is depleted in G1-G2 relative to the average upper and lower continental crust. Muscovite, a late-stage magmatic/subsolidus mineral, is the major host of Li, Nb, In, Sn and W in G2 granites. G2 granites are spatially associated with W-Sn greisen mineralisation. Fractionation within the younger G3-G4 granite system enriched Li (average 364 ppm), Ga (28 ppm), In (80 ppb), Sn (14 ppm), Nb (27 ppm), Ta (4.6 ppm), W (6.3 ppm) and Bi (0.61 ppm) in the G4 granites with retention of Be in G3 granites due to partitioning of Be into cordierite during fractionation. The distribution of Nb and Ta is controlled by accessory phases such as rutile within the G4 granites, facilitated by high F and lowering the melt temperature, leading to disseminated Nb and Ta mineralisation. Lithium, In, Sn and W are hosted in biotite micas which may prove favourable for breakdown on ingress of hydrothermal fluids. Higher degrees of scattering on trace element plots may be attributable to fluid–rock interactions or variability within the magma chamber. The G3-G4 system is more boron-rich, evidenced by a higher modal abundance of tourmaline. In this system, there is a stronger increase of Sn compared to G1-G2 granites, implying Sn in tourmaline-dominated mineral lodes may represent exsolution from G4 granites. G1-G4 granite abundances can be accounted for by 20–30% partial melting and 10–40% fractionation of a greywacke source. G5 granites are analogues of Rare Metal Granites described in France and Germany. These granites are enriched in Li (average 1363 ppm), Ga (38 ppm), Sn (21 ppm), W (24 ppm), Nb (52 ppm) and Ta (15 ppm). Within G5 granites, the metals partition into accessory minerals such as rutile, columbite-tantalite and cassiterite, forming disseminated magmatic mineralisation. High observed concentrations of Li, In, Sn, W, Nb and Ta in G4 and G5 granites are likely facilitated by high F, Li and P, which lower melt temperature and promote retention of these elements in the melt, prior to crystallisation of disseminated magmatic mineralisation

    Does Endogenous Technical Change Make a Difference in Climate Policy Analysis? A Robustness Exercise with the FEEM-RICE Model

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    Defining the critical hurdles in cancer immunotherapy

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    Scientific discoveries that provide strong evidence of antitumor effects in preclinical models often encounter significant delays before being tested in patients with cancer. While some of these delays have a scientific basis, others do not. We need to do better. Innovative strategies need to move into early stage clinical trials as quickly as it is safe, and if successful, these therapies should efficiently obtain regulatory approval and widespread clinical application. In late 2009 and 2010 the Society for Immunotherapy of Cancer (SITC), convened an "Immunotherapy Summit" with representatives from immunotherapy organizations representing Europe, Japan, China and North America to discuss collaborations to improve development and delivery of cancer immunotherapy. One of the concepts raised by SITC and defined as critical by all parties was the need to identify hurdles that impede effective translation of cancer immunotherapy. With consensus on these hurdles, international working groups could be developed to make recommendations vetted by the participating organizations. These recommendations could then be considered by regulatory bodies, governmental and private funding agencies, pharmaceutical companies and academic institutions to facilitate changes necessary to accelerate clinical translation of novel immune-based cancer therapies. The critical hurdles identified by representatives of the collaborating organizations, now organized as the World Immunotherapy Council, are presented and discussed in this report. Some of the identified hurdles impede all investigators; others hinder investigators only in certain regions or institutions or are more relevant to specific types of immunotherapy or first-in-humans studies. Each of these hurdles can significantly delay clinical translation of promising advances in immunotherapy yet if overcome, have the potential to improve outcomes of patients with cancer

    Development and Validation of a Risk Score for Chronic Kidney Disease in HIV Infection Using Prospective Cohort Data from the D:A:D Study

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    Ristola M. on työryhmien DAD Study Grp ; Royal Free Hosp Clin Cohort ; INSIGHT Study Grp ; SMART Study Grp ; ESPRIT Study Grp jäsen.Background Chronic kidney disease (CKD) is a major health issue for HIV-positive individuals, associated with increased morbidity and mortality. Development and implementation of a risk score model for CKD would allow comparison of the risks and benefits of adding potentially nephrotoxic antiretrovirals to a treatment regimen and would identify those at greatest risk of CKD. The aims of this study were to develop a simple, externally validated, and widely applicable long-term risk score model for CKD in HIV-positive individuals that can guide decision making in clinical practice. Methods and Findings A total of 17,954 HIV-positive individuals from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study with >= 3 estimated glomerular filtration rate (eGFR) values after 1 January 2004 were included. Baseline was defined as the first eGFR > 60 ml/min/1.73 m2 after 1 January 2004; individuals with exposure to tenofovir, atazanavir, atazanavir/ritonavir, lopinavir/ritonavir, other boosted protease inhibitors before baseline were excluded. CKD was defined as confirmed (>3 mo apart) eGFR In the D:A:D study, 641 individuals developed CKD during 103,185 person-years of follow-up (PYFU; incidence 6.2/1,000 PYFU, 95% CI 5.7-6.7; median follow-up 6.1 y, range 0.3-9.1 y). Older age, intravenous drug use, hepatitis C coinfection, lower baseline eGFR, female gender, lower CD4 count nadir, hypertension, diabetes, and cardiovascular disease (CVD) predicted CKD. The adjusted incidence rate ratios of these nine categorical variables were scaled and summed to create the risk score. The median risk score at baseline was -2 (interquartile range -4 to 2). There was a 1: 393 chance of developing CKD in the next 5 y in the low risk group (risk score = 5, 505 events), respectively. Number needed to harm (NNTH) at 5 y when starting unboosted atazanavir or lopinavir/ritonavir among those with a low risk score was 1,702 (95% CI 1,166-3,367); NNTH was 202 (95% CI 159-278) and 21 (95% CI 19-23), respectively, for those with a medium and high risk score. NNTH was 739 (95% CI 506-1462), 88 (95% CI 69-121), and 9 (95% CI 8-10) for those with a low, medium, and high risk score, respectively, starting tenofovir, atazanavir/ritonavir, or another boosted protease inhibitor. The Royal Free Hospital Clinic Cohort included 2,548 individuals, of whom 94 individuals developed CKD (3.7%) during 18,376 PYFU (median follow-up 7.4 y, range 0.3-12.7 y). Of 2,013 individuals included from the SMART/ESPRIT control arms, 32 individuals developed CKD (1.6%) during 8,452 PYFU (median follow-up 4.1 y, range 0.6-8.1 y). External validation showed that the risk score predicted well in these cohorts. Limitations of this study included limited data on race and no information on proteinuria. Conclusions Both traditional and HIV-related risk factors were predictive of CKD. These factors were used to develop a risk score for CKD in HIV infection, externally validated, that has direct clinical relevance for patients and clinicians to weigh the benefits of certain antiretrovirals against the risk of CKD and to identify those at greatest risk of CKD.Peer reviewe
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