52 research outputs found

    The 9p21.3 risk of childhood acute lymphoblastic leukaemia is explained by a rare high-impact variant in CDKN2A

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    Genome-wide association studies (GWAS) have provided strong evidence for inherited predisposition to childhood acute lymphoblastic leukaemia (ALL) identifying a number of risk loci. We have previously shown common SNPs at 9p21.3 influence ALL risk. These SNP associations are generally not themselves candidates for causality, but simply act as markers for functional variants. By means of imputation of GWAS data and subsequent validation SNP genotyping totalling 2,177 ALL cases and 8,240 controls, we have shown that the 9p21.3 association can be ascribed to the rare highimpact CDKN2A p.Ala148Thr variant (rs3731249; Odds ratio=2.42, P=3.45×10−19). The association between rs3731249 genotype and risk was not specific to particular subtype of B-cell ALL. The rs3731249 variant is associated with predominant nuclear localisation of the CDKN2A transcript suggesting the functional effect of p.Ala148Thr on ALL risk may be through compromised ability to inhibit cyclin D within the cytoplasm

    Pacific island regional preparedness for El Niño

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    The El Niño Southern Oscillation (ENSO) cycle is often blamed for disasters in Pacific island communities. From a disaster risk reduction (DRR) perspective, the challenges with the El Niño part of the ENSO cycle, in particular, are more related to inadequate vulnerability reduction within development than to ENSO-induced hazard influences. This paper analyses this situation, filling in a conceptual and geographic gap in El Niño-related research, by reviewing El Niño-related preparedness (the conceptual gap) for Pacific islands (the geographic gap). Through exploring El Niño impacts on Pacific island communities alongside their vulnerabilities, resiliences, and preparedness with respect to El Niño, El Niño is seen as a constructed discourse rather than as a damaging phenomenon, leading to suggestions for El Niño preparedness as DRR as part of development. Yet the attention which El Niño garners might bring resources to the Pacific region and its development needs, albeit in the short term while El Niño lasts. Conversely, the attention given to El Niño could shift blame from underlying causes of vulnerability to a hazard-centric viewpoint. Instead of focusing on one hazard-influencing phenomenon, opportunities should be created for the Pacific region to tackle wider DRR and development concerns

    Medium-size-vessel vasculitis

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    Medium-size-artery vasculitides do occur in childhood and manifest, in the main, as polyarteritis nodosa (PAN), cutaneous PAN and Kawasaki disease. Of these, PAN is the most serious, with high morbidity and not inconsequential mortality rates. New classification criteria for PAN have been validated that will have value in epidemiological studies and clinical trials. Renal involvement is common and recent therapeutic advances may result in improved treatment options. Cutaneous PAN is a milder disease characterised by periodic exacerbations and often associated with streptococcal infection. There is controversy as to whether this is a separate entity or part of the systemic PAN spectrum. Kawasaki disease is an acute self-limiting systemic vasculitis, the second commonest vasculitis in childhood and the commonest cause of childhood-acquired heart disease. Renal manifestations occur and include tubulointerstitial nephritis and renal failure. An infectious trigger and a genetic predisposition seem likely. Intravenous immunoglobulin (IV-Ig) and aspirin are effective therapeutically, but in resistant cases, either steroid or infliximab have a role. Greater understanding of the pathogenetic mechanisms involved in these three types of vasculitis and better long-term follow-up data will lead to improved therapy and prediction of prognosis

    Lower crustal contamination of Deccan Traps magmas: evidence from tholeiitic dykes and granulite xenoliths from western India

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    Evidence for the nature of contaminants of Deccan Traps magmas may be provided by crustal xenoliths in lamprophyre and tholeiitic dykes that intruded the Deccan lava pile towards the end of volcanic activity. The potential contaminants are represented by xenoliths that include mafic (plagioclase-poor) granulites and felsic (plagioclase-rich) granulites. The granulites in general are peraluminous, light-rare-earth-enriched and have high Ba/Nb, very low Sm/Nd and Rb/Sr ratios. The protoliths of mafic granulites were mostly cumulates (high Mg#, low SiO2/Al2O3) of sub-alkaline magmas. The felsic granulites are metaigneous quartz-normative rocks and have relatively low concentration of Ba and Sr compared to the mafic types. The dykes consist of picritic basalts and two varieties of tholeiitic basalts, and in general show a complex mineralogy indicative of magma mixing. The picrites have primitive Mg#s, relatively high Nb, Zr, Sr, Ba and Ba/Y, with relatively low Nb/Zr and Nb/Y compared to the more evolved tholeiites. In terms of Sr-Nd isotope systematics the older (thol I) dykes are less contaminated compared to the younger ones (thol II). These characteristics are consistent with fractional crystallisation and mixing between evolved and primitive tholeiitic melts coupled with assimilation of lower crustal felsic granulites. Petrogenetic modelling indicates fairly high rates of contamination for mafic magmas with high abundances of both compatible and incompatible elements. Similar processes of lower crustal contamination may have resulted in production of two of the major Deccan Traps lava formations, the Poladpur and Mahabaleshwar Formations, which are geochemically analogous to the tholeiitic dykes

    Plasma nitriding of CA-6NM steel: effect of H2 + N2 gas mixtures in nitride layer formation for low N2 contents at 500 ºC

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    This work aims to characterize the phases, thickness, hardness and hardness profiles of the nitride layers formed on the CA-6NM martensitic stainless steel which was plasma nitrided in gas mixtures containing different nitrogen amounts. Nitriding was performed at 500 ºC temperature, and 532 Pa (4 Torr) pressure, for gas mixtures of 5% N2 + 95% H2, 10% N2 + 90% H2, and 20% N2 + 80% H2, and 2 hours nitriding time. A 6 hours nitriding time condition for gas mixture of 5% N2 + 95% H2 was also studied. Nitrided samples results were compared with non-nitrided condition. Thickness and microstructure of the nitrided layers were characterized by optical microscopy (OM), using Villela and Nital etchants, and the phases were identified by X-ray diffraction. Hardness profiles and hardness measured on surface steel were determined using Vickers hardness and nanoindentation tester, respectively. It was verified that nitrided layer produced in CA-6NM martensitc stainless steel is constituted of compound layer, being that formation of the diffusion zone was not observed for the studied conditions. The higher the nitrogen amounts in gas mixture the higher is the thickness of the nitrided layer and the probability to form different nitride phases, in the case γ'-Fe4N, ε-Fe2-3N and CrN phases. Intrinsic hardness of the nitrided layers produced in the CA-6NM stainless steel is about 12-14 GPa (~1200-1400 HV)
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