298 research outputs found
The certification of the gross calorific value and mass fractions of ash, C, H, N, S, Cl, major elements and trace elements in three coal materials: ERM®-EF411 (hard coal), ERM®-EF412 (brown coal) and ERM®-EF413 (furnace coke)
This report describes the production of ERM-EF411, ERM-EF412 and ERM-EF413, three coal materials certified for proximates and trace elements. The materials have been produced following ISO Guide 34:2009.
Industial hard coal, brown coal and furnace coke were obtained, dried, milled (ERM-EF411 and ERM-EF413) and filled into aluminium laminated sachets.
Between-unit homogeneity were quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. Within-unit heterogeneity was quantified to determine the minimum sample intake.
The material was characterised by an intercomparison among laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated on statistical grounds only.
Uncertainties of the certified values were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible heterogeneity and instability and to characterisation.
The materials are intended for quality control and assessment of method performance. As any reference material, they can be used for control charts or validation studies, as well. The CRMs are available in sachets containing 50 g of dried material. The minimum amount of sample to be used, depending on the analyte, varies from 30 mg to 1 g.
The CRM was accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.JRC.D.2-Standards for Innovation and sustainable Developmen
The Certification of Mass Fractions of Aflatoxin B1, B2, G1 and G2 in Compound Feedingstuff (low level), Certified Reference Material ERM®-BE375
This report describes the preparation of a compound feeding stuff (ERM-BE375) matrix reference material its characterisation for the aflatoxins B1, B2, G1 and G2 mass fractions.
The preparation of the material, between bottle homogeneity and stability studies and the characterisation with a discussion of the results is described hereafter. Uncertainties were calculated in compliance with the ISO/IEC Guide 98-3:2008 (GUM) [2] and include contributions from possible hidden between bottle heterogeneity, long-term storage, the characterisation study and the contribution from the common calibrant.JRC.DG.D.2-Reference material
Certification of the Mass Concentrations of Ammonium, Chloride, Fluoride, Magnesium, Nitrate, Ortho-Phosphate, Sulfate and of pH and Conductivity in Simulated Rainwater - Certified Reference Material ERM®-CA408
This report presents the preparation and certification of the simulated rainwater certified reference material ERM-CA408. All the steps required for the production of this water-matrix certified reference material are described in detail, from the preparation of the simulated rainwater until the characterization exercise that lead to the final assignment of the certified values, following ISO Guide 34:2009 [1] and ISO Guide 35:2006 [2]. Homogeneity and stability of the water material were investigated with dedicated studies and the certification campaign for the material characterisation was based on an inter-comparison among several experienced laboratories. IRMM organised and coordinated all the phases of this project including evaluation of data. The certified values were calculated as the unweighted mean of the laboratory means of the accepted sets of results for each parameter, see below. Uncertainties were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM, ISO/IEC Guide 98-3:2008) [3]. The stated expanded uncertainties include contributions from characterisation, homogeneity and stability.JRC.DG.D.2-Reference material
Certification of the mass concentration of arsenic, cadmium, chromium, copper, iron, manganese, mercury, lead, nickel and selenium in wastewater: ERM®-CA713
The report describes the production and certification of the certified reference material ERM-CA713 Wastewater. The material was produced to replace the existing materials BCR-713, BCR-714 and BCR-715 because of changes in the legislation, in particular the requirement for the monitoring of Hg as a priority substance. The material is certified for As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Se. and will serve as a quality control tool for the laboratories involved in the mandatory monitoring of the Priority Substances prescribed under the Water Framework Directive (WFD, 2000/60/EC).JRC.D.2-Standards for Innovation and sustainable Developmen
CERTIFICATION REPORT The certification of the mass fraction and mass concentration of total Hg in seawater: ERM®-CA400
This report describes the production of ERM-CA400, a seawater material certified for the mass concentration and mass fraction (calculated from the (certified) density) of total Hg. The material was produced following ISO Guide 34:2009 [[i]].
Approximately 500 litres of surface seawater were collected from The Netherlands and transferred into a pre-cleaned polyester tank. Upon arrival at the JRC Geel, the water was acidified and passed first through a 0.8 µm , then through a 0.45 µm filter into another pre-cleaned tank. After filtration, the water was spiked with mercury to achieve a final concentration of total Hg of approximately 20 ng/L. Aliquots of 100 mL were dispensed into borosilicate glass ampoules which were flame sealed and sterilised by gamma ray irradiation.
Between ampoule-homogeneity was quantified and stability during dispatch and storage were assessed following ISO Guide 35:2006 [[ii]].
The material was characterised by means of an inter-comparison among laboratories of demonstrated competence and adhering to ISO/IEC 17025 for Hg and by a primary method of measurement, confirmed by independent results for density. Technically invalid results were removed, but no outlier was eliminated on statistical grounds only.
Uncertainties of the certified values were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) [[iii]] and include uncertainties related to possible inhomogeneity, instability and characterisation.
The material is intended for the quality control and assessment of method performance. As any reference material, it can also be used for control charts or validation studies. The CRM is available as a set of three borosilicate glass ampoules each containing 100 mL of acidified seawater. The minimum amount of sample to be used is 10 g.
The CRM was accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.JRC.F.6-Reference Material
N-acetyltransferase 2 polymorphism in Parkinson's disease. The Rotterdam study
The N-acetyltransferase-2 gene (NAT-2) has been associated with Parkinson's disease. The genotype associated with slow acetylation has been reported to be increased in patients with Parkinson's disease. Three mutant alleles M1, M2, and M3 of NAT-2 were investigated in 80 patients with idiopathic Parkinson's disease and 161 age matched randomly selected controls from a prospective population based cohort study. The allelic frequencies and genotypic distributions in patients were very similar to those found in controls. In controls the frequency of the wild type allele increased significantly with age suggesting that the mutant alleles are associated with an increased risk of mortality. These findings suggest that NAT-2 polymorphism is not a major genetic determinant of idiopathic Parkinson's disease, but may be a determinant of mortality in the general population
Lack of association of two common polymorphisms on 9p21 with risk of coronary heart disease and myocardial infarction; results from a prospective cohort study
Background: Recent genome wide association (GWA) studies identified two Single Nucleotide Polymorphisms (SNP) (rs10757278 and rs10757274) in the region of the CDK2NA and CDK2NB genes to be consistently associated with the risks of coronary heart disease (CHD) and myocardial infarction (MI). We examined the SNPs in relation to the risk of CHD and MI in a large population based study of elderly population. Methods: The Rotterdam Study is a population-based, prospective cohort study among 7983 participants aged 55 years and older. Associations of the polymorphisms with CHD and MI were assessed by use of Cox proportional hazards analyses. Results: In an additive model, the age and sex adjusted hazard ratios (HRs) (95% confidence interval) for CHD and MI were 1.03 (0.90, 1.18) and 0.94 (0.82, 1.08) per copy of the G allele of rs10757274. The corresponding HRs were 1.03 (0.90, 1.18) and 0.93 (0.81, 1.06) for the G allele of rs10757278. The association of the SNPs with CHD and MI was not significant in any of the subgroups of CHD risk factors. Conclusion: We were not able to show an association of the studied SNPs with risks of CHD and MI. This may be due to differences in genes involved in the occurrence of CHD in young and older people
Exome sequencing and functional analyses suggest that SIX6 is a gene involved in an altered proliferation-differentiation balance early in life and optic nerve degeneration at old age
Primary open-angle glaucoma (POAG) is a hereditary neurodegenerative disease, characterized by optic nerve changes including increased excavation, notching and optic disc hemorrhages. The excavation can be described by the vertical cup-disc ratio (VCDR). Previously, genome-wide significant evidence for the association of rs10483727 in SIX1-SIX6 locus with VCDR and subsequent POAG was found. Using 1000 genomes-based imputation of four independent population-based cohorts in the Netherlands, we identified a missense variant rs33912345 (His141Asn) in SIX6 associated with VCDR (Pmeta = 7.74 Ă— 10-7, n = 11 473) and POAG (Pmeta = 6.09 Ă— 10-3, n = 292). Exome sequencing analysis revealed another missense variant rs146737847 (Glu129Lys) also in SIX6 associated with VCDR (P = 5.09 Ă— 10-3, n = 1208). These two findings point to SIX6 as the responsible gene for the previously reported association signal. Functional characterization of SIX6 in zebrafish revealed that knockdown of six6b led to a small eye phenotype. Histological analysis showed retinal lamination, implying an apparent normal development of the eye, but an underdeveloped lens, and reduced optic nerve diameter. Expression analysis of morphants at 3 dpf showed a 5.5-fold up-regulation of cdkn2b, a cyclin-dependent kinase inhibitor, involved in cell cycle regulation and previously associated with VCDR and POAG in genome-wide association studies (GWASs). Since both six6b and cdkn2b play a key role in cell proliferation, we assessed the proliferative activity in the eye of morphants and found an alteration in the proliferative pattern of retinal cells. Our findings in humans and zebrafish suggest a functional involvement of six6b in early eye development, and open new insights into the genetic architecture of POAG
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