Evaluation of the ammonia emission sensitivity of secondary inorganic aerosol concentrations measured by the national reference method

Abstract Previous comparisons between the Reference and Definitive Methods for measuring serum cholesterol have demonstrated a small but persistent positive bias in the Reference Method, averaging about +1.6%. Here we describe the results of further investigations designed to better characterize the nature of this bias. Analysis of a well-characterized model serum sample (SRM 909) suggests that more than half of the difference in cholesterol values determined by the two methods is the result of small contributions from cholesterol precursor sterols and phytosterols, which are also measured for the Reference Method. An additional significant contribution may be from cholesterol oxidation products, particularly 7-hydroxycholesterol isomers, which are active in the Liebermann-Burchard reaction. The 7-hydroxycholesterol in SRM 909, most of which appeared to be already present in the serum rather than formed during saponification, may account for as much as 20% of the observed difference between the methods. Contributions from other possible sources, including impurities in the cholesterol standard and incomplete saponification of cholesteryl esters, are very small. Because the observed bias is both quite small and consistent among samples, the cholesterol Reference Method continues to meet all of the requirements generally expected for a dependable and effective Reference Method.

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Comparison of two multiplex immunochromatographic assays for the rapid detection of major carbapenemases in Enterobacterales

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkaa043 ◽

2020 ◽

Vol 75 (6) ◽

pp. 1491-1494 ◽

Cited By ~ 3

Author(s):

Pierre Bogaerts ◽

Anne-Sophie Berger ◽

Stéphanie Evrard ◽

Te-Din Huang

Keyword(s):

Rapid Detection ◽

Reference Method ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Mean Intensity ◽

Reference Center ◽

National Reference ◽

The Mean ◽

Imagej Software ◽

National Reference Center

Abstract Objectives Two commercially available lateral flow immunochromatographic assays (ICAs) for detection of the major carbapenemases were prospectively assessed for the detection of carbapenemases in Enterobacterales: RESIST-4 O.K.N.V. (Coris BioConcept) and NG-Test CARBA 5 (NG Biotech). Methods These two assays were performed prospectively on consecutive Enterobacterales suspected of producing a carbapenemase that were referred to the Belgian National Reference Center for Monitoring Antimicrobial Resistance in Gram-Negative Bacteria between March and June 2018. The intensity of the band corresponding to a carbapenemase for each test was compared using ImageJ software. Results Of the 161 isolates tested, a carbapenemase was detected in 91 (60 OXA-48-like, 15 VIM, 9 KPC, 5 NDM, 1 IMP and 1 IMP + OXA-48); in the remaining 70, no carbapenemases were detected. For both tests, the results were 100% concordant with the results of the PCR-sequencing reference method. Two IMP producers were only detected by NG-Test CARBA 5 as IMP is not targeted by RESIST-4 O.K.N.V. The mean intensity of the OXA-48, VIM and NDM bands displayed by NG-Test CARBA 5 was 3 to 3.7 times higher than for RESIST-4 O.K.N.V., while the KPC band was on average 1.7 times more intense with RESIST-4 O.K.N.V. Conclusions RESIST-4 O.K.N.V. and NG-Test CARBA 5 are two efficient assays for identification of the major carbapenemases. NG-Test CARBA 5 offers the advantage of detecting IMP, which remains rare in Western countries.

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Modelling changes in secondary inorganic aerosol formation and nitrogen deposition in Europe from 2005 to 2030

10.5194/acp-2021-342 ◽

2021 ◽

Author(s):

Jan Eiof Jonson ◽

Hilde Fagerli ◽

Thomas Scheuschner ◽

Svetlana Tsyro

Keyword(s):

Critical Loads ◽

Fine Particles ◽

Regional Scale ◽

Ammonia Emission ◽

Ammonia Emissions ◽

Aerosol Formation ◽

European Continent ◽

Reduced Nitrogen ◽

Inorganic Aerosol ◽

Oxidised Nitrogen

Abstract. Secondary inorganic PM2.5 particles are formed from SOx, NOx and ammonia emissions, through the formation of either ammonium sulphate or ammonium nitrate. EU limits and WHO guidelines for PM2.5 levels are frequently exceeded in Europe, in particular in the winter months. In addition the critical loads for eutrophication are exceeded in most of the European continent. Further reductions in ammonia emissions and other PM precursors beyond the 2030 requirements could alleviate some of the health burden from fine particles, and also reduce the deposition of nitrogen to vulnerable ecosystems. Using the regional scale EMEP/MSC-W model, we have studied the effects of year 2030 ammonia emissions on PM2.5 concentrations and depositions of nitrogen in Europe in the light of present (2017) and past (2005) conditions. Our calculations show that in Europe the formation of PM2.5 from ammonia to a large extent is limited by the ratio between the emissions of ammonia on one hand, and SOx plus NOx, on the other hand. As the ratio of ammonia to SOx and NOx is increasing, the potential to further curb PM2.5 levels through reductions in ammonia emissions is decreasing. Here we show that per gram of ammonia emissions mitigated, the resulting reductions in PM2.5 levels simulated using 2030 emissions are about a factor of 2.6 lower than when 2005 emissions are used. However, this ratio is lower in winter, thus further reductions in the ammonia emissions in winter may have similar potentials as SOx and NOx in curbing PM2.5 levels in this season. Following the expected reductions of ammonia emission, depositions of reduced nitrogen should also decrease in Europe. However, as the reductions in NOx emission are larger than for ammonia, the fraction of total nitrogen (reduced plus oxidised nitrogen) deposited as reduced nitrogen is increasing and may exceed 60 % in most of Europe by 2030. Thus the potential for future reductions in the exceedances of critical loads for eutrophication in Europe will mainly rely on the ability to reduce ammonia emissions.

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Comparison of the GeneFinderTM COVID-19 Plus RealAmp Kit on the sample-to-result Platform ELITe InGenius to the national reference method: An added value of N gene target detection?

Journal of Clinical Virology ◽

10.1016/j.jcv.2020.104632 ◽

2020 ◽

Vol 132 ◽

pp. 104632

Author(s):

David S.Y. Ong ◽

Eric C.J. Claas ◽

Simone Breijer ◽

Norbert Vaessen

Keyword(s):

Target Detection ◽

Reference Method ◽

Added Value ◽

N Gene ◽

Gene Target ◽

National Reference

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First Proficiency Testing To Evaluate the Ability of European Union National Reference Laboratories To Detect Staphylococcal Enterotoxins in Milk Products

Journal of AOAC International ◽

10.1093/jaoac/86.2.332 ◽

2003 ◽

Vol 86 (2) ◽

pp. 332-339 ◽

Cited By ~ 13

Author(s):

Jacques-Antoine Hennekinne ◽

Martine Gohier ◽

Tiphaine Maire ◽

Christiane Lapeyre ◽

Bertrand Lombard ◽

...

Keyword(s):

European Union ◽

Proficiency Testing ◽

Reference Method ◽

Enzyme Linked Immunosorbent Assay ◽

Milk Products ◽

Staphylococcal Enterotoxins ◽

National Reference ◽

Freeze Dried ◽

Uninoculated Control ◽

The Eu

Abstract The European Commission has designed a network of European Union-National Reference Laboratories (EU-NRLs), coordinated by a Community Reference Laboratory (CRL), for control of hygiene of milk and milk products (Council Directive 92/46/ECC). As a common contaminant of milk and milk products such as cheese, staphylococcal enterotoxins are often involved in human outbreaks and should be monitored regularly. The main tasks of the EU-CRLs were to select and transfer to the EU-NRLs a reference method for detection of enterotoxins, and to set up proficiency testing to evaluate the competency of the European laboratory network. The first interlaboratory exercise was performed on samples of freeze-dried cheese inoculated with 2 levels of staphylococcal enterotoxins (0.1 and 0.25 ng/g) and on an uninoculated control. These levels were chosen considering the EU regulation for staphylococcal enterotoxins in milk and milk products and the limit of detection of the enzyme-linked immunosorbent assay test recommended in the reference method. The trial was conducted according to the recommendations of ISO Guide 43. Results produced by laboratories were compiled and compared through statistical analysis. Except for data from 2 laboratories for the uninoculated control and cheese inoculated at 0.1 ng/g, all laboratories produced satisfactory results, showing the ability of the EU-NRL network to monitor the enterotoxin contaminant.

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Validation of Five Gas Analysers for Application in Ammonia Emission Measurements at Livestock Houses According to the VERA Test Protocol

Applied Sciences ◽

10.3390/app10155034 ◽

2020 ◽

Vol 10 (15) ◽

pp. 5034

Author(s):

Shaojie Zhuang ◽

Eva Brusselman ◽

Bart Sonck ◽

Peter Demeyer

Keyword(s):

Measurement Errors ◽

Reference Method ◽

Field Measurements ◽

Alternative Methods ◽

Mitigation Measures ◽

Ammonia Emission ◽

Production Test ◽

Test Protocol ◽

Wet Chemistry ◽

Chemistry Method

Ammonia emissions are an important issue in livestock production. Many mitigation measures have been proposed in order to reduce the environmental impact of livestock farms, and reliable field measurements are required to evaluate the amount of released or reduced ammonia while applying these measures. Following the guideline of the Verification of Environmental Technologies for Agricultural Production test protocol, five commercially available gas analysers, i.e., INNOVA 1314, Picarro G2103, Rosemount CT5100, Gasmet CX4000, and Axetris LGD F200-A, were validated as alternative methods to the wet-chemistry method (reference method) for measuring ammonia in livestock houses. High correlations ( r > 0.99 ) were found between the analysers and the reference method. The measurement errors of the tested analysers were below 2 ppmv or 10%. Equivalence to the wet-chemistry method was demonstrated for the INNOVA and Rosemount analysers without a recalibration and for the Picarro and Axetris analysers with a recalibration. The Gasmet analyser was seemingly subjected to an interference from carbon-dioxide and, after compensating for the cross-sensitivity, the equivalence to the wet-chemistry method could also be demonstrated. Calibration curves that were based on a certified gas cylinder were inconsistent with that based on wet-chemistry measurements, which suggested that field calibration might be necessary for optimal measurement accuracy.

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Methodological limitations in measuring childhood and adolescent obesity and overweight in epidemiological studies: does overweight fare better than obesity?

Public Health Nutrition ◽

10.1017/s1368980007000584 ◽

2007 ◽

Vol 10 (10A) ◽

pp. 1112-1120 ◽

Cited By ~ 8

Author(s):

Lluís Serra-Majem ◽

Lourdes Ribas-Barba ◽

Carmen Pérez-Rodrigo ◽

Joy Ngo ◽

Javier Aranceta

Keyword(s):

Random Sample ◽

Reference Data ◽

International Comparisons ◽

Personal Data ◽

Reference Method ◽

Children And Youth ◽

Obesity Prevalence ◽

Cross Sectional ◽

National Reference ◽

Obesity And Overweight

AbstractObjectivesInternational definitions of childhood obesity based on body mass index (BMI) are intended to be used for international comparisons of obesity prevalence. In general, they are not appropriate to be used in clinical practice. The objective of this study is to compare international-ecological vs. national-clinical reference data of obesity in Spain, as well as to describe trends.DesignCross-sectional study from a representative national random sample of Spanish children and youth conducted between 1998 and 2000. Prevalence estimates of obesity in a national random sample of Spanish children and youth are presented in this paper, defined by age- and sex-specific BMI national reference standards for the 85th percentile (overweight) and 95th percentile (obesity), as well as by Cole et al. criteria. The study protocol included personal data, data on education and socio-economic status for the family and anthropometric measurements.SettingPopulation-based study set in Spain.SubjectsA random sample of 3534 individuals, aged 2–24 years.ResultsPrevalence of obesity using national reference data was higher (15.3%) than using international data (5.8%), but overweight rates were similar. Agreement observed for both definitions was low for obesity but higher for overweight. Obesity trends among children and adolescents in Spain show increasing patterns in boys but not in girls.ConclusionsResults indicate the need to standardise the definitions of obesity and overweight in childhood and recommend the use of overweight due to the greater degree of agreement observed among the different methods used. The IOTF reference method underestimates obesity rates in Spanish schoolchildren.

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Determination of serum cholesterol by isotope dilution mass spectrometry with a benchtop capillary gas chromatograph/mass spectrometer: comparison with the National Reference System's Definitive and Reference Methods

Clinical Chemistry ◽

10.1093/clinchem/37.7.1161 ◽

1991 ◽

Vol 37 (7) ◽

pp. 1161-1165 ◽

Cited By ~ 11

Author(s):

John H Eckfeldt ◽

Linda A Lewis ◽

John D Belcher ◽

Jasbir Singh ◽

Ivan D Frantz

Keyword(s):

Mass Spectrometry ◽

Mass Spectrometer ◽

Isotope Dilution ◽

Isotope Dilution Mass Spectrometry ◽

Internal Standard ◽

Reference Method ◽

Gas Chromatograph ◽

National Reference ◽

Definitive Methods

Abstract We developed an isotope dilution mass spectrometric cholesterol method with [25,26,27-13C]cholesterol as internal standard and a benchtop gas chromatograph/mass spectrometer (GC/MS) that is much easier and less time consuming than previously described Reference and Definitive Methods for cholesterol. The internal standard, cholesterol standards, and unknown specimen are delivered volumetrically with an automated dilutor and the saponifying reagent. After saponification, extraction, and derivatization, specimens are injected into a benchtop quadrupole MS with an autosampler. Unknown cholesterol concentrations are calculated automatically by comparing the peak area ratio of the m/z = 368, 371 ion pair with the ratios for the cholesterol standards (0 to 12.93 mmol/L). We found within-run and day-to-day (overall) imprecision of 0.44% and 0.95%, respectively, when specimens were assayed singly. In several lyophilized and frozen Standard Reference Material (SRM) pools, cholesterol results with our GC/MS method averaged 0.4% less than the National Institute for Standards and Technology definitive GC/MS result performed about three years earlier. Our GC/MS results averaged 1.3% and 2.0% less than results by the National Reference System (NRS) Abell-Levy-Brodie-Kendall (ALBK) results from clinical specimens and the SRM pools, respectively. These results are consistent with the previously reported bias between the NRS Reference and Definitive Methods and the 0.1% per year decrease in cholesterol concentrations in SRM pools as determined by GC/MS analysis. These results further emphasize the small but consistent bias between cholesterol results by isotope dilution mass spectrometry and the ALBK Reference Method, the latter being the basis for the National Cholesterol Education Program guidelines and population reference values.

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Standardization of a commercial (Boehringer Mannheim diagnostics) enzymic method for cholesterol.

Clinical Chemistry ◽

10.1093/clinchem/35.3.409 ◽

1989 ◽

Vol 35 (3) ◽

pp. 409-413 ◽

Cited By ~ 8

Author(s):

G R Warnick ◽

M Spain ◽

H Kloepfer ◽

T M Volke

Keyword(s):

National Cholesterol Education Program ◽

Reference Method ◽

Comparison Analysis ◽

National Reference ◽

True Value ◽

Matrix Interactions ◽

Method Accuracy ◽

Laboratory Standardization ◽

Kendall Method ◽

Good Agreement

Abstract The Laboratory Standardization Panel of the National Cholesterol Education Program recommends that cholesterol method accuracy ideally be within 3% of the true value determined by the Abell-Kendall Reference Method, a component of the National Reference System for Cholesterol. As one of the Abell-Kendall network laboratories established to facilitate cholesterol standardization, the approach we recommend for determining accuracy involves a comparison analysis on patients' specimens by the method in question and by the Abell-Kendall method. Use of fresh specimens precludes matrix interactions that may influence enzymic measurement. Using this approach, we assessed an enzymic method for cholesterol with two instruments (Boehringer Mannheim/Hitachi 717 and 737), with BMD reagent, controls, and calibrator. Fresh and frozen sera were analyzed with both instruments over three days. The Abell-Kendall method was used at the Northwest Lipid Research Center on frozen aliquots of the same sera. Both instruments demonstrated good agreement with the Reference Method, as determined by linear regression; overall bias averaged less than -2% for the Hitachi 717 and -1% for the Hitachi 737 at 2000 mg/L--i.e., within the accuracy recommendation. We observed a difference in bias for fresh and frozen specimens; with the Hitachi 717, fresh specimens exhibited -3% bias at 2000 mg/L, but there was virtually no bias of determinations of frozen specimens.

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