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1.
Matern Child Health J ; 28(5): 873-886, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38147276

RESUMO

INTRODUCTION: An unprecedented shortage of infant formula occurred in the United States (U.S.) in 2022 and posed widespread challenges to infant feeding nationwide. The purpose of this study is to investigate mothers' experiences during the 2022 infant formula shortage and its perceived impacts on infants' diet and health. METHODS: Mothers (n = 45) of infants under 8 months old from Washington D.C. were invited to participate in a virtual study meeting during the summer of 2022. Mothers completed surveys regarding their demographics, infants' anthropometrics, infant feeding practices, information they have received about infant feeding, and knowledge about infant feeding practices. They then participated in a qualitative interview about their experiences during the infant formula shortage. RESULTS: Overarching themes were: the shortage (1) had adverse impacts on mothers' mental and emotional health; (2) had significant financial and intangible costs; (3) led to changes in infant feeding practices; (4) social and family networks were helpful in navigating the shortage; and (5) mothers felt fortunate to have resources to breastfeed and/or obtain formula. DISCUSSION: The infant formula shortage adversely impacted mothers' mental and emotional health, and was costly, in terms of financial and intangible costs. Findings demonstrate the need to develop clinical and policy approaches to support mothers in feeding their infants and provide education about safe infant feeding practices.


Assuntos
Fórmulas Infantis , Mães , Lactente , Feminino , Humanos , Washington , Mães/psicologia , Aleitamento Materno/psicologia , Comportamento Alimentar , Conhecimentos, Atitudes e Prática em Saúde
2.
Lancet ; 378(9785): 73-85, 2011 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-21511329

RESUMO

Hepatitis delta virus (HDV) is a small, defective RNA virus that can infect only individuals who have hepatitis B virus (HBV); worldwide more than 15 million people are co-infected. There are eight reported genotypes of HDV with unexplained variations in their geographical distribution and pathogenicity. The hepatitis D virion is composed of a coat of HBV envelope proteins surrounding the nucleocapsid, which consists of a single-stranded, circular RNA genome complexed with delta antigen, the viral protein. HDV is clinically important because although it suppresses HBV replication, it causes severe liver disease with rapid progression to cirrhosis and hepatic decompensation. The range of clinical presentation is wide, varying from mild disease to fulminant liver failure. The prevalence of HDV is declining in some endemic areas but increasing in northern and central Europe because of immigration. Treatment of HDV is with pegylated interferon alfa; however, response rates are poor. Increased understanding of the molecular virology of HDV will identify novel therapeutic targets for this most severe form of chronic viral hepatitis.


Assuntos
Hepatite D , Vírus Delta da Hepatite/fisiologia , Hepatite B/complicações , Hepatite D/complicações , Hepatite D/diagnóstico , Hepatite D/tratamento farmacológico , Hepatite D/epidemiologia , Vírus Delta da Hepatite/genética , Humanos , Prevalência , Replicação Viral
3.
Liver Int ; 32(1): 128-36, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22098564

RESUMO

BACKGROUND AND AIMS: High density lipoprotein (HDL) plays an important role in the transport of cholesterol to the adrenal gland for steroidogenesis and may have actions that modulate response to infection and critical illness. The clinical relevance of HDL level in patients with liver failure remains poorly characterised. METHODS: In 164 critically-ill patients with acute (ALF) and acute on chronic liver failure (AOCLF) we evaluated the relationship between HDL levels measured on admission to intensive care unit (ICU) and survival, predisposition to sepsis and adrenocortical function assessed through the cortisol response to short synacthen testing (SST). RESULTS: In acute liver failure and acute on chronic liver failure, high density lipoprotein levels were significantly lower in non-survivors (P < 0.01). Levels correlated closely with biochemical markers of liver function and the duration of liver failure. However, predictive accuracy was not superior to conventional markers and on multi-variate analysis did not show independent association with survival. Low HDL concentration was not associated with an increased incidence of sepsis either precipitating or complicating ICU admission. Evidence of adrenocortical insufficiency was present in more than half of patients undergoing SST and HDL level but not other lipid parameters correlated closely with cortisol increment after SST (r = 0.364, P < 0.0001). CONCLUSIONS: High density lipoprotein levels are low in patients with liver failure and reflect its severity. Levels are lower in non-survivors but do not offer an advantage as early indicators of prognosis over conventional markers. No evidence of a major predisposing role for infection was found, but findings suggest a close link to adrenal function.


Assuntos
Glândulas Suprarrenais/metabolismo , Insuficiência Adrenal/diagnóstico , Doença Hepática Induzida por Substâncias e Drogas/diagnóstico , Doença Hepática Terminal/diagnóstico , Lipoproteínas HDL/sangue , Falência Hepática Aguda/diagnóstico , Sepse/diagnóstico , Glândulas Suprarrenais/fisiopatologia , Insuficiência Adrenal/sangue , Insuficiência Adrenal/mortalidade , Adulto , Doença Hepática Induzida por Substâncias e Drogas/sangue , Doença Hepática Induzida por Substâncias e Drogas/mortalidade , Estudos de Coortes , Doença Hepática Terminal/sangue , Doença Hepática Terminal/mortalidade , Feminino , Humanos , Falência Hepática Aguda/sangue , Falência Hepática Aguda/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Sepse/sangue , Sepse/mortalidade , Taxa de Sobrevida , Reino Unido/epidemiologia
4.
Mar Pollut Bull ; 183: 114076, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36057157

RESUMO

Biocides used in offshore oil and gas operations could be present in water discharges, and thus identifying such chemicals and their hazard could help address concerns regarding non-target organisms. Aquatic toxicity data, queried from different sources and augmented with predictive models, were used to develop species sensitivity distributions and their corresponding 5th percentile hazard concentrations (HC5s). Curated data, including over 1000 empirical records for 137 species, indicated no evidence of bias when comparing sensitivity between marine and freshwater species, even when predicted data were used. HC5s facilitated estimation of an acute-to-chronic ratio (ACR = 10), appropriate for most chemicals and useful in filling data gaps. Comparison of chronic-HC5s with the default approach for deriving predicted no effect concentrations showed that the latter systematically overstates aquatic hazard. The present approach shows promise of using acute-to-chronic HC5 ratios for defining assessment factors for different chemical classes, instead of the use of generic assessment factors.


Assuntos
Desinfetantes , Poluentes Químicos da Água , Organismos Aquáticos , Desinfetantes/toxicidade , Água Doce , Medição de Risco , Especificidade da Espécie , Água , Poluentes Químicos da Água/toxicidade
5.
Environ Toxicol Chem ; 40(5): 1255-1265, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33315272

RESUMO

Routine whole effluent toxicity (WET) testing is commonly used to monitor effluent discharges for regulatory compliance in North America. However, the use of fish in WET testing raises ethical concerns and therefore an important question to be explored is whether invertebrates can be used to reduce and/or replace the need for vertebrate testing. The present study evaluated WET data collected for regulatory compliance between 2003 and 2019 (n = 2581 endpoints) from 20 different stationary onshore and offshore oil and gas facilities located across Canada and the United States. Our objective was to assess the relative sensitivity between vertebrates (i.e., fish) and invertebrates in paired samples and to evaluate trends in WET compliance. Despite the variability in testing endpoints, invertebrates displayed equal to or greater sensitivity to tested effluents than fish. For example, based on no-observed-effect concentrations for survival and growth, Americamysis bahia was found to be protective of Menidia beryllina in 90% of endpoint comparisons (n = 336). The results also indicated that regulatory compliance was high (94-100%), with most WET tests passing the established criteria by large margins (79-251%). The results of this comprehensive analysis of historical WET data can be used to improve future permit testing requirements and help answer the question of whether fish tests are needed for routine WET testing. Environ Toxicol Chem 2021;40:1255-1265. © 2020 SETAC.


Assuntos
Poluentes Químicos da Água , Animais , Crustáceos , Peixes , Invertebrados , Testes de Toxicidade , Estados Unidos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
6.
Environ Toxicol Chem ; 39(3): 721-730, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900942

RESUMO

Unlike most other conventional petroleum products that are derived from crude oil, gas-to-liquids (GTLs) are petroleum products that are synthesized from natural gas (methane). This process results in GTL products having no sulfur and low aromatic content, so they should have less impact on human health and the environment compared with crude oil-derived products. The GTLs have been registered for use as nonaqueous base fluids (NABFs) in drilling muds, which aid in the process of drilling wells for oil and gas extraction; it is through these uses and others that they enter terrestrial environments. The primary objective of the present study was to determine whether GTLs were less toxic to terrestrial soil biota than conventional NABFs used for land-based drilling, such as diesel and low-toxicity mineral oil (LTMO). A second objective was to understand the fate and impact of these fluids under more realistic soil and aging conditions of a common west Texas (USA) oil-producing region (i.e., sandy loam soil with low organic matter and a hot arid climate). Acute terrestrial toxicity studies were conducted on the soft-bodied terrestrial invertebrate earthworm (Eisenia fetida) along with 3 plant species-alfalfa (Medicago stavia), thickspike wheatgrass (Elymus lanceolatus), and fourwing saltbrush (Atriplex canescens). We also assessed changes in microbial community structure of the soils following additions of NABF. Overall, the GTL NABFs had lower toxicity compared with conventional NABFs like diesel and LTMO, as measured by invertebrate toxicity, plant seed germination, and impact on the microbial community. Environ Toxicol Chem 2020;39:721-730. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.


Assuntos
Atriplex/efeitos dos fármacos , Elymus/efeitos dos fármacos , Medicago sativa/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Oligoquetos/efeitos dos fármacos , Petróleo/efeitos adversos , Animais , Indústria de Petróleo e Gás , Microbiologia do Solo , Texas
7.
Sci Total Environ ; 734: 139191, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32460069

RESUMO

Naphthenic acid fraction compounds (NAFCs), defined herein as the polar organic compounds extracted from the acidified oil sands process water (OSPW) samples using dichloromethane, are becoming the research hotspot due to their presence in large amount in OSPW and along with other potentially NA-contaminated water streams from the mining site. Fourier transform infrared spectroscopy (FTIR) method is commonly used to quantify NAFCs and assumes that the total NA concentration is measured as the sum of the responses for all carboxylic acid functional groups. In this study, the NAFCs in various OSPW and groundwater (GW) samples from an active oil sands mining site were analyzed using FTIR. All water samples were pretreated using either solid-phase extraction (SPE) or liquid-liquid extraction (LLE) methods before analysis. The results showed that SPE produced higher recoveries of NAFCs than LLE for most water samples under current experimental conditions. For the quantification of NAFCs, commercial Fluka NA mixture and a pre-calibrated OSPW extract were employed as the calibration standards. The NAFCs calibrated with Fluka NA mixture and OSPW extract had clear linear relationships. The concentrations of NAFCs obtained using OSPW extract standard curve were 2.5 times the NAFC concentrations obtained using the Fluka NA mixture standard curve. Additionally, good linear correlations were observed between the total NAs and O2-O6 NA species determined by ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-TOFMS) and the NAFCs measured by FTIR. According to these correlations, the NA compositions in NAFCs were developed, and the relative abundances of O2-O6 NA species in NAFCs were similar for SPE and LLE pretreated samples. The findings of this study demonstrated that FTIR could be used as a promising tool to monitor total NA species and to estimate the NA profile in different environmental water samples.

8.
Environ Toxicol Chem ; 38(12): 2811-2823, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31441964

RESUMO

A study was performed to evaluate the potential biological impacts from 8 different miscellaneous discharges from an oil and gas mobile offshore drilling unit (MODU) including deck drainage, desalination unit waste, boiler blowdown, fire control system test water, noncontact cooling water, and bilge water. Samples were evaluated for toxicity using a rapid (<1 h) initial screening test (echinoderm [Dendraster excentricus] fertilization test), and if toxicity was found, further testing was conducted using 3 chronic whole-effluent toxicity tests. This additional testing included the embryo larval development 72-h echinoderm (D. excentricus); 7-d mysid (Americamysis bahia) survival, growth, and fecundity invertebrate test; and 7-d topsmelt (Atherinops affinis) survival and growth fish test. Toxicity identification evaluations were performed on 3 discharges that consistently elicited a toxic response during whole-effluent toxicity testing. To place the results of the toxicity testing into the context of environmental risk, the spatial extent of potential biological effects was investigated using the CORMIX mixing zone model. The output of the modeling indicated that discharge of selected effluents did not result in concentrations, or duration of exposure, that would elicit toxic effects to organisms living in the surrounding environment. The present study provides a comprehensive data set that was used to characterize potential toxicity and environmental risk of MODU "miscellaneous discharges" which could help inform future risk assessments of these discharges. Environ Toxicol Chem 2019;38:2811-2823. © 2019 SETAC.


Assuntos
Poluição por Petróleo/análise , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/química , Animais , Crustáceos/efeitos dos fármacos , Crustáceos/crescimento & desenvolvimento , Desenvolvimento Embrionário/efeitos dos fármacos , Peixes/crescimento & desenvolvimento , Larva/efeitos dos fármacos , Metais/química , Metais/toxicidade , Ouriços-do-Mar/efeitos dos fármacos , Ouriços-do-Mar/crescimento & desenvolvimento , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade
10.
Sci Total Environ ; 631-632: 829-839, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29727993

RESUMO

Large volumes of oil sands process-affected water (OSPW) are generated during the extraction of bitumen from oil sands in the Athabasca region of northeastern Alberta, Canada. As part of the development of treatment technologies, molecular characterization of naphthenic acids (NAs) and naphthenic acid fraction compounds (NAFC) in wetlands is a topic of research to better understand their fate and behavior in aquatic environments. Reported here is the application of high-resolution negative-ion electrospray Orbitrap-mass spectrometry for molecular characterization of NAs and NAFCs in a non-aerated constructed treatment wetland. The effectiveness of the wetlands to remove OSPW-NAs and NAFCs was evaluated by monitoring the changes in distributions of NAFC compounds in the untreated sample and non-aerated treatment system. After correction for measured evapotranspiration, the removal rate of the classical NAs followed approximately first-order kinetics, with higher rates observed for structures with relatively higher number of carbon atoms. These findings indicate that constructed wetland treatment is a viable method for removal of classical NAs in OSPW. Work is underway to evaluate the effects of wetland design on water quality improvement, preferential removal of different NAFC species, and reduction in toxicity.

11.
Sci Total Environ ; 645: 277-285, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30029109

RESUMO

The classical, oxidized, and heteroatomic naphthenic acids (NAs) species were monitored in the oil sands process water (OSPW) and groundwater from the active oil sands operation area, using solid phase extraction sample preparation and high resolution mass spectrometry analysis. Groundwater samples include Pleistocene channel aquifer groundwater (PLCA) and oil sands basal aquifer groundwater (OSBA) from different depth of underground. The concentrations of Ox-NAs decreased from OSPW to PLCA, and then increased from PLCA to OSBA, which is deeper than PLCA. The NAs in PLCA mainly comprised of Ox-NAs and N-NAs and the percentage of S-NAs was negligible. Results revealed relative abundances of individual NA species in total NAs varies among different water layers and the potential environmental impacts are expected to be variable. Principal component analysis results of O2-NAs or O4-NAs could be used for differentiation of water types. O2-NAs with n = 12-16 and |Z| = 4-6, and O4-NAs with n = 14-20 and |Z| = 6-8, were identified as marker compounds that could serve as surrogates of the larger complex NA mixture for source differentiation. This work utilized a combination of sample preparation, instrumental analysis, and statistical analysis methods to obtain knowledge of the occurrence, composition, and transfer of NAs in the groundwater of the Alberta oil sands operation area.

12.
Water Res ; 128: 129-137, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29100206

RESUMO

This work reports the monitoring and assessment of naphthenic acids (NAs) in oil sands process-affected water (OSPW), Pleistocene channel aquifer groundwater (PLCA), and oil sands basal aquifer groundwater (OSBA) from an active oil sands development in Alberta, Canada, using ultra performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) analysis with internal standard (ISTD) and external standard (ESTD) calibration methods and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) for compositional analysis. PLCA was collected at 45-51 m depth and OSBA was collected at 67-144 m depth. Results of Ox-NA concentrations follow an order as OSPW > OSBA > PLCA, indicating that occurrences of NAs in OSBA were likely related to natural bitumen deposits instead of OSPW. Liquid-liquid extraction (LLE) was applied to avoid the matrix effect for the ESTD method. Reduced LLE efficiency accounted for the divergence of the ISTD and ESTD calibrated results for oxidized NAs. Principle component analysis results of O2 and O4 species could be employed for differentiation of water types, while classical NAs with C13-15 and Z (-4)-(-6) and aromatic O2-NAs with C16-18 and Z (-14)-(-16) could be measured as marker compounds to characterize water sources and potential temporal variations of samples, respectively. FTICR-MS results revealed that compositions of NA species varied greatly among OSPW, PLCA, and OSBA, because of NA transfer and transformation processes. This work contributed to the understanding of the concentration and composition of NAs in various types of water, and provided a useful combination of analytical and statistical tools for monitoring studies, in support of future safe discharge of treated OSPW.


Assuntos
Ácidos Carboxílicos/análise , Água Subterrânea/análise , Poluentes Químicos da Água/análise , Alberta , Cromatografia Líquida , Análise de Fourier , Água Subterrânea/química , Espectrometria de Massas/métodos , Campos de Petróleo e Gás , Análise de Componente Principal
13.
Environ Toxicol Chem ; 37(11): 2745-2757, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30359486

RESUMO

Since the 1940s, effluent toxicity testing has been used to assess potential ecological impacts of effluents and help determine necessary treatment options for environmental protection prior to release. Strategic combinations of toxicity tests, analytical tools, and biological monitoring have been developed. Because the number of vertebrates utilized in effluent testing is thought to be much greater than that used for individual chemical testing, there is a new need to develop strategies to reduce the numbers of vertebrates (i.e., fish) used. This need will become more critical as developing nations begin to use vertebrates in toxicity tests to assess effluent quality. A workshop was held to 1) assess the state of science in effluent toxicity testing globally; 2) determine current practices of regulators, industry, private laboratories, and academia; and 3) explore alternatives to vertebrate (fish) testing options and the inclusion of modified/new methods and approaches in the regulatory environment. No single approach was identified, because of a range of factors including regulatory concerns, validity criteria, and wider acceptability of alternatives. However, a suite of strategies in a weight-of-evidence approach would provide the flexibility to meet the needs of the environment, regulators, and the regulated community; and this "toolbox" approach would also support reduced reliance on in vivo fish tests. The present Focus article provides a brief overview of wastewater regulation and effluent testing approaches. Alternative methodologies under development and some of the limitations and barriers to regulatory approaches that can be selected to suit individual country and regional requirements are described and discussed. Environ Toxicol Chem 2018;37:2745-2757. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.


Assuntos
Alternativas aos Testes com Animais/métodos , Internacionalidade , Medição de Risco , Testes de Toxicidade/métodos , Poluentes Químicos da Água/análise , Animais , Humanos , Controle Social Formal
14.
Environ Toxicol Chem ; 36(11): 3148-3157, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28628243

RESUMO

Previous assessments of oil sands process-affected water (OSPW) toxicity were hampered by lack of high-resolution analytical analysis, use of nonstandard toxicity methods, and variability between OSPW samples. We integrated ultrahigh-resolution mass spectrometry with a toxicity identification evaluation (TIE) approach to quantitatively identify the primary cause of acute toxicity of OSPW to rainbow trout (Oncorhynchus mykiss). The initial characterization of OSPW toxicity indicated that toxicity was associated with nonpolar organic compounds, and toxicant(s) were further isolated within a range of discrete methanol fractions that were then subjected to Orbitrap mass spectrometry to evaluate the contribution of naphthenic acid fraction compounds to toxicity. The results showed that toxicity was attributable to classical naphthenic acids, with the potency of individual compounds increasing as a function of carbon number. Notably, the mass of classical naphthenic acids present in OSPW was dominated by carbon numbers ≤16; however, toxicity was largely a function of classical naphthenic acids with ≥17 carbons. Additional experiments found that acute toxicity of the organic fraction was similar when tested at conductivities of 400 and 1800 µmhos/cm and that rainbow trout fry were more sensitive to the organic fraction than larval fathead minnows (Pimephales promelas). Collectively, the results will aid in developing treatment goals and targets for removal of OSPW toxicity in water return scenarios both during operations and on mine closure. Environ Toxicol Chem 2017;36:3148-3157. © 2017 SETAC.


Assuntos
Ácidos Carboxílicos/toxicidade , Cyprinidae , Mineração , Campos de Petróleo e Gás , Oncorhynchus mykiss , Águas Residuárias/química , Poluentes Químicos da Água/toxicidade , Animais , Ácidos Carboxílicos/análise , Larva/efeitos dos fármacos , Espectrometria de Massas , Poluentes Químicos da Água/análise
15.
Environ Toxicol Chem ; 36(9): 2503-2513, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28294396

RESUMO

There is consensus that fish are the most sensitive aquatic organisms to selenium (Se) and that Se concentrations in fish tissue are the most reliable indicators of potential toxicity. Differences in Se speciation, biological productivity, Se concentration, and parameters that affect Se bioavailability (e.g., sulfate) may influence the relationship between Se concentrations in water and fish tissue. It is desirable to identify environmentally protective waterborne Se guidelines that, if not exceeded, reduce the need to directly measure Se concentrations in fish tissue. Three factors that should currently be considered in developing waterborne Se screening guidelines are 1) differences between lotic and lentic sites, 2) the influence of exposure concentration on Se partitioning among compartments, and 3) the influence of sulfate on selenate bioavailability. Colocated data sets of Se concentrations in 1) water and particulates, 2) particulates and invertebrates, and 3) invertebrates and fish tissue were compiled; and a quantile regression approach was used to derive waterborne Se screening guidelines. Use of a regression-based approach for describing relationships in Se concentrations between compartments reduces uncertainty associated with selection of partitioning factors that are generally not constant over ranges of exposure concentrations. Waterborne Se screening guidelines of 6.5 and 3.0 µg/L for lotic and lentic water bodies were derived, and a sulfate-based waterborne Se guideline equation for selenate-dominated lotic waters was also developed. Environ Toxicol Chem 2017;36:2503-2513. © 2017 SETAC.


Assuntos
Compostos de Selênio/análise , Poluentes Químicos da Água/análise , Animais , Monitoramento Ambiental , Peixes , Água Doce/química , Invertebrados , Ácido Selênico/análise , Ácido Selênico/toxicidade , Compostos de Selênio/toxicidade , Sulfatos/análise , Poluentes Químicos da Água/toxicidade
16.
Chemosphere ; 187: 376-384, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28863291

RESUMO

There are several established methods for the determination of naphthenic acids (NAs) in waters associated with oil sands mining operations. Due to their highly complex nature, measured concentration and composition of NAs vary depending on the method used. This study compared different common sample preparation techniques, analytical instrument methods, and analytical standards to measure NAs in groundwater and process water samples collected from an active oil sands operation. In general, the high- and ultrahigh-resolution methods, namely high performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and Orbitrap mass spectrometry (Orbitrap-MS), were within an order of magnitude of the Fourier transform infrared spectroscopy (FTIR) methods. The gas chromatography mass spectrometry (GC-MS) methods consistently had the highest NA concentrations and greatest standard error. Total NAs concentration was not statistically different between sample preparation of solid phase extraction and liquid-liquid extraction. Calibration standards influenced quantitation results. This work provided a comprehensive understanding of the inherent differences in the various techniques available to measure NAs and hence the potential differences in measured amounts of NAs in samples. Results from this study will contribute to the analytical method standardization for NA analysis in oil sands related water samples.


Assuntos
Ácidos Carboxílicos/análise , Fracionamento Químico/métodos , Campos de Petróleo e Gás/química , Análise Espectral/métodos , Poluentes Químicos da Água/análise , Calibragem , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Extração Líquido-Líquido/normas , Espectrometria de Massas , Métodos , Mineração , Extração em Fase Sólida/normas , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral/normas
17.
Nurs Stand ; 19(10): 47-52; quiz 54, 56, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15612431
18.
J Virol Methods ; 184(1-2): 55-62, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22613674

RESUMO

Hepatitis delta virus (HDV) causes both acute and chronic hepatitis, always in the presence of hepatitis B. Analysis of global HDV isolates has shown that at least eight genotypes exist. HDV RNA quantitation and genotyping are important tools in the diagnosis and management of infected individuals. There is, as yet, no commercially available quantitative HDV RNA assay. Several laboratories have developed in-house assays, but equivalent detection and quantitation across all HDV genotypes has not been demonstrated. In this study, the development of an in-house real-time reverse transcription polymerase chain reaction (RT PCR) assay is described to quantify HDV RNA in serum or plasma. Its efficiency was validated by testing 99 samples from patients with known chronic HDV infection, along with 22 samples from individuals without HDV. The assay has a dynamic range of 6.4×10(2) to 6.4×10(8)copies/mL. Amplicons of the quantitative PCR can be directly used for sequence analysis and genotyping. HDV-1, HDV-5 and HDV-6 were identified, reflecting the areas of origin of our cohort of patients. The ability to genotype and to accurately quantify HDV RNA levels in the more recently discovered African genotypes will be important for investigating the natural history of HDV in this group, compared to those with genotype 1 disease.


Assuntos
Hepatite D/virologia , Vírus Delta da Hepatite/isolamento & purificação , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Soro/virologia , Carga Viral/métodos , Vírus Delta da Hepatite/genética , Humanos , Londres , RNA Viral/genética
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