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1.
Matern Child Health J ; 21(7): 1563-1572, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28188472

RESUMO

Background Maternal postpartum depression (PPD) could affect children's emotional development, increasing later risk of child psychological problems. The aim of our study was to assess the association between child's emotional and behavioural problems and mother's PPD, considering maternal current mental health problems (CMP). Methods This is a secondary analysis from the EU-Childhood Obesity Project (NCT00338689). Women completed the Edinburgh Postnatal Depression Scale (EPDS) at, 2, 3 and 6 months after delivery and the General Health Questionnaire (GHQ-12) to assess CMP once the children reached the age of 8 years. EPDS scores > 10 were defined as PPD and GHQ-12 scores > 2 were defined as CMP. The psychological problems of the children at the age of eight were collected by mothers through the Child's Behaviour Checklist (CBCL). Results 473, 474 and 459 mothers filled in GHQ-12 and CBCL tests at 8 years and EPDS at 2, 3 and 6 months, respectively. Anxiety and depression was significantly increased by maternal EPDS. Children whose mothers had both PPD and CMP exhibited the highest levels of psychological problems, followed by those whose mothers who had only CMP and only PPD. PPD and CMP had a significant effect on child's total psychological problems (p = 0.033, p < 0.001, respectively). Children whose mothers had PPD did not differ from children whose mothers did not have any depression. Conclusions Maternal postpartum depression and current mental health problems, separately and synergistically, increase children's psychological problems at 8 years.


Assuntos
Ansiedade/complicações , Transtornos do Comportamento Infantil/epidemiologia , Filho de Pais com Deficiência , Depressão Pós-Parto/psicologia , Emoções , Mães/psicologia , Ansiedade/psicologia , Criança , Depressão , Depressão Pós-Parto/diagnóstico , Depressão Pós-Parto/epidemiologia , Feminino , Humanos , Saúde Mental , Relações Mãe-Filho , Gravidez , Comportamento Problema , Escalas de Graduação Psiquiátrica , Inquéritos e Questionários , Fatores de Tempo
2.
Med Intensiva ; 39(6): 337-44, 2015.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-25443330

RESUMO

OBJECTIVE: To analyze the profile, incidence of life support therapy limitation (LSTL) and donation potential in neurocritical patients. STUDY DESIGN: A multicenter prospective study was carried out. SETTING: Nine hospitals authorized for organ harvesting for transplantation. PATIENTS: All patients consecutively admitted to the hospital with GCS < 8 during a 6-month period were followed-up until discharge or day 30 of hospital stay. STUDY VARIABLES: Demographic data, cause of coma, clinical status upon admission and outcome were analyzed. LSTL, brain death (BD) and organ donation incidence were recorded. RESULTS: A total of 549 patients were included, with a mean age of 59.0 ± 14.5 years. The cause of coma was cerebral hemorrhage in 27.0% of the cases.LSTL was applied in 176 patients (32.1%). In 78 cases LSTL consisted of avoiding ICU admission. Age, the presence of contraindications, and specific causes of coma were associated to LSTL. A total of 58.1% of the patients died (n=319). One-hundred and thirty-three developed BD (24.2%), and 56.4% of these became organ donors (n=75). The presence of edema and mid-line shift on the CT scan, and transplant coordinator evaluation were associated to BD. LSTL was associated to a no-BD outcome. Early LSTL (first 4 days) was applied in 9 patients under 80 years of age, with no medical contraindications for donation and a GCS ≤ 4 who finally died in asystole. CONCLUSIONS: LSTL is a frequent practice in neurocritical patients. In almost one-half of the cases, LSTL consisted of avoiding admission to the ICU, and on several occasions the donation potential was not evaluated by the transplant coordinator.


Assuntos
Morte Encefálica , Coma/terapia , Cuidados Críticos , Eutanásia Passiva , Cuidados para Prolongar a Vida , Recusa em Tratar/estatística & dados numéricos , Doadores de Tecidos/provisão & distribuição , Coleta de Tecidos e Órgãos , Obtenção de Tecidos e Órgãos/organização & administração , Adulto , Idoso , Idoso de 80 Anos ou mais , Dano Encefálico Crônico/etiologia , Morte Encefálica/diagnóstico , Coma/etiologia , Coma/mortalidade , Feminino , Humanos , Unidades de Terapia Intensiva/estatística & dados numéricos , Cuidados para Prolongar a Vida/estatística & dados numéricos , Masculino , Futilidade Médica , Pessoa de Meia-Idade , Estudos Prospectivos , Espanha , Assistência Terminal/estatística & dados numéricos , Coleta de Tecidos e Órgãos/estatística & dados numéricos , Obtenção de Tecidos e Órgãos/métodos
3.
Med Intensiva ; 38(2): 73-82, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23485500

RESUMO

OBJECTIVE: A comparison was made of the oxidative stress (OS) levels of patients with either viral or bacterial severe community-acquired pneumonia (sCAP) and of patients without infection (healthy volunteers (HV) and patients with acute myocardial infarction (AMI)). DESIGN: A prospective observational study was made. PATIENTS: Critically ill patients with sCAP. VARIABLES: The TBARS level was measured as an index of oxidative injury. SOD, CAT and redox glutathione system (GSH, GSSG, GR, GPx) activities were measured as reflecting antioxidant capacity. Severity of illness was assessed by the APACHE II, SOFA and SIRS scores. RESULTS: Thirty-seven subjects were included: 15 patients with CAP (12 of bacterial origin [BCAP] and 3 due to 2009 A/H1N1 virus [VCAP]), 10 HV and 12 AMI patients. Intensive care CAP mortality was 26.7% (n=4). Plasmatic TBARS levels were higher in CAP patients than in HV, but similar to those recorded in AMI patients. In contrast, VCAP was associated with lower TBARS levels, and some components of the glutathione redox system were higher in BCAP patients and HV. The OS levels did not differ between survivors and non-survivors. CONCLUSION: Our results suggest the occurrence of higher OS in sCAP patients compared with HV. In contrast, lower TBARS levels were observed in VCAP patients, suggesting an increase of antioxidant activity related to the redox glutathione system. However, further research involving a larger cohort is needed in order to confirm these findings.


Assuntos
Imunocompetência , Estresse Oxidativo , Pneumonia Bacteriana/metabolismo , Pneumonia Viral/metabolismo , Adulto , Infecções Comunitárias Adquiridas/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Índice de Gravidade de Doença
4.
Med Intensiva ; 35(1): 6-12, 2011.
Artigo em Espanhol | MEDLINE | ID: mdl-21122950

RESUMO

OBJECTIVES: To assess Southern European intensive care unit nurses' knowledge about evidence-based guidelines for the prevention of ventilator-associated pneumonia and to compare these findings with a pan-European perspective. DESIGN: A sub-analysis from an observational study performed using a 9-questions, multiple-choice questionnaire performed during the period October 2006 - March 2007. SETTING: Six Southern European countries, selected from 22 participant European countries. PARTICIPANTS: Volunteer nurses from intensive care units. RESULTS: 3329 questionnaires were obtained, 1182 of them belonging to Southern European countries with a 75.8% response rate. Global average score was 45.1%, being it significantly better in the South of Europe (46.6%, P<.001). A linear multiple regression analysis showed that years of working experience (per class of increase) (B=0.154 ± (SD) 0.045) (95% CI (0.066-0.242))(p=0.001) and working in a smaller intensive care unit (B=-0.210 ± (SD) 0.059)((95% CI) -0.326-0.094)(P<.001) was independently associated with better test scores. CONCLUSIONS: Southern European critical care nurses' knowledge about ventilator-associated pneumonia prevention is poor, but significantly better than in the pan-European countries.


Assuntos
Cuidados Críticos , Enfermagem Baseada em Evidências , Enfermagem , Pneumonia Associada à Ventilação Mecânica/prevenção & controle , Guias de Prática Clínica como Assunto , Europa (Continente) , Feminino , Humanos , Masculino , Inquéritos e Questionários
5.
Med Intensiva (Engl Ed) ; 43(6): 352-361, 2019.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-29747939

RESUMO

OBJECTIVE: To determine factors related to limitations on life support within 48h of intensive care unit (ICU) admission. STUDY DESIGN: Prospective multicenter study. SETTING: Eleven ICUs. PATIENTS: All patients who died and/or had limitations on life support after ICU admission during a four-month period. VARIABLES: Patient characteristics, hospital characteristics, characteristics of limitations on life support. Time-to-first-limitation was classified as early (<48h of admission) or late (≥48h). We performed univariate, multivariate analyses and CHAID (chi-square automatic interaction detection) analysis of variables associated with limitation of life support within 48h of ICU admission. RESULTS: 3335 patients were admitted; 326 (9.8%) had limitations on life support. A total of 344 patients died; 247 (71.8%) had limitations on life support (range among centers, 58.6%-84.2%). The median (p25-p75) time from admission to initial limitation was 2 (0-7) days. CHAID analysis found that the modified Rankin score was the variable most closely related with early limitations. Among patients with Rankin >2, early limitations were implemented in 71.7% (OR=2.5; 95% CI: 1.5-4.4) and lung disease was the variable most strongly associated with early limitations (OR=12.29; 95% CI: 1.63-255.91). Among patients with Rankin ≤2, 48.8% had early limitations; patients admitted after emergency surgery had the highest rate of early limitations (66.7%; OR=2.4; 95% CI: 1.1-5.5). CONCLUSION: Limitations on life support are common, but the practice varies. Quality of life has the greatest impact on decisions to limit life support within 48h of admission.


Assuntos
Cuidados Críticos/normas , Cuidados para Prolongar a Vida/normas , Suspensão de Tratamento , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Admissão do Paciente , Estudos Prospectivos , Fatores de Tempo
6.
J Steroid Biochem Mol Biol ; 108(3-5): 221-9, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18061438

RESUMO

Endometrial carcinoma (EC) is the most common gynecological malignancy in the western world. A widely accepted dualistic model, which has been established on a morphological basis, differentiates EC into two broad categories: Type I oestrogen-dependent adenocarcinoma with an endometrioid morphology and Type II non-oestrogen-dependent EC with a serous papillary or clear cell morphology. Molecular genetic evidence indicates that endometrial carcinoma, as described in other malignancies, likely develops as the result of a stepwise accumulation of alterations in cellular regulatory pathways, such as oncogene activation and tumor suppressor gene inactivation, which lead to dysfunctional cell growth. These molecular alterations appear to be specific in Type I and Type II cancers. In type I endometrioid endometrial cancer, PTEN gene silencing in conjunction with defects in DNA mismatch repair genes, as evidenced by the microsatellite instability phenotype, or mutations in the K-ras and/or beta-catenin genes, are recognized major alterations, which define the progression of the normal endometrium to hyperplasia, to endometrial intraepithelial neoplasia, and then on to carcinoma. In contrast, Type II cancers show mutations of TP53 and Her-2/neu and seem to arise from a background of atrophic endometrium. Nevertheless, despite the great effort made to establish a molecularly-based histological classification, the following issues must still be clarified: what triggers the tumor cells to invade the myometrium and what causes vascular or lymphatic dissemination, finally culminating in metastasis? RUNX1, a transcription factor, was recently identified as one of the most highly over-expressed genes in a microarray study of invasive endometrial carcinoma. Another candidate gene, which may be associated with an initial switch to myometrial infiltration, is the transcription factor ETV5/ERM. These studies, as well as those conducted for other genes possibly involved in the mitotic checkpoint as a major mechanism of carcinogenesis in non-endometrioid endometrial cancer, could help in understanding the differences in the biology and the clinical outcome among histological types.


Assuntos
Carcinoma Endometrioide/genética , Neoplasias do Endométrio/patologia , Adenocarcinoma/patologia , Adenocarcinoma de Células Claras/patologia , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Cistadenocarcinoma Papilar/patologia , Reparo de Erro de Pareamento de DNA , Feminino , Genes erbB-2/genética , Genes p53/genética , Genes ras/genética , Humanos , Instabilidade de Microssatélites , Neoplasias Hormônio-Dependentes/patologia , Oncogenes/genética , PTEN Fosfo-Hidrolase/genética , Receptores de Estrogênio/genética , Receptores de Progesterona/genética
7.
Appl Radiat Isot ; 66(11): 1711-7, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18513984

RESUMO

A new Certified Reference Material (CRM) for radionuclides in sediment (IAEA-385) is described and the results of the certification process are presented. Eleven radionuclides ((40)K, (137)Cs, (226)Ra, (228)Ra, (230)Th, (232)Th, (234)U, (238)U, (238)Pu, (239+240)Pu and (241)Am) have been certified and information mass activities with 95% confidence intervals are given for seven other radionuclides ((90)Sr, (210)Pb((210)Po), (235)U, (239)Pu, (240)Pu and (241)Pu). Results for less frequently reported radionuclides ((60)Co, (99)Tc, (134)Cs, (155)Eu, (224)Ra and (239)Np) and information on some activity and mass ratios are also reported. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in sediment samples, for the development and validation of analytical methods and for training purposes.


Assuntos
Sedimentos Geológicos/análise , Guias de Prática Clínica como Assunto , Monitoramento de Radiação/normas , Radioisótopos/análise , Radioisótopos/normas , Irlanda , Oceanos e Mares , Doses de Radiação , Valores de Referência
8.
Clin Transl Oncol ; 9(5): 272-7, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17525037

RESUMO

Endometrial carcinoma is the most common gynaecological malignancy in the western world and the most frequent among infiltrating tumours of the female genital tract. Despite the characterisation of molecular events associated with the development of endometrial carcinoma, those associated with the early steps of infiltration and invasion in endometrial cancer are less known. Deep myometrial invasion correlates with more undifferentiated tumours, lymph-vascular invasion, node affectation and decreased global survival. In this review we present an overview of the molecular pathology of myometrial infiltration that defines the initial steps of invasion in endometrial cancer. Down-regulation of E-cadherin as a main player of epithelial to mesenchymal transition, as well as modifications on other molecules involved in cell-cell contacts, render cells with a migratory phenotype. In addition, altered signalling pathways and transcription factors associate with myometrial invasion, histologic grade and metastasis.


Assuntos
Neoplasias do Endométrio/etiologia , Neoplasias do Endométrio/patologia , Moléculas de Adesão Celular/fisiologia , Neoplasias do Endométrio/genética , Feminino , Expressão Gênica , Humanos , Invasividade Neoplásica
9.
J Environ Radioact ; 166(Pt 1): 195-201, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27156160

RESUMO

Liquid scintillation counting (LSC) is a commonly used technique for the determination of alpha and beta emitters. However, LSC has poor resolution and the continuous spectra for beta emitters hinder the simultaneous determination of several alpha and beta emitters from the same spectrum. In this paper, the feasibility of multivariate calibration by partial least squares (PLS) models for the determination of several alpha (natU, 241Am and 226Ra) and beta emitters (40K, 60Co, 90Sr/90Y, 134Cs and 137Cs) in water samples is reported. A set of alpha and beta spectra from radionuclide calibration standards were used to construct three PLS models. Experimentally mixed radionuclides and intercomparision materials were used to validate the models. The results had a maximum relative bias of 25% when all the radionuclides in the sample were included in the calibration set; otherwise the relative bias was over 100% for some radionuclides. The results obtained show that LSC-PLS is a useful approach for the simultaneous determination of alpha and beta emitters in multi-radionuclide samples. However, to obtain useful results, it is important to include all the radionuclides expected in the studied scenario in the calibration set.


Assuntos
Monitoramento de Radiação/instrumentação , Contagem de Cintilação/instrumentação , Poluentes Radioativos da Água/análise , Monitoramento de Radiação/métodos , Contagem de Cintilação/métodos
10.
Appl Radiat Isot ; 128: 263-269, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28753525

RESUMO

Liquid scintillation spectrometry (LSS) is a meaningful technique for the determination of alpha and beta emitters. However, this technique is highly affected by quenching phenomena, which reduce the counting efficiency, shift the spectra to low energies and cause misclassification problems. In this paper, a selection of chemical and colour quench agents was evaluated to study the influence of alpha and beta energy and the quenching effect on the detection efficiency, the shape of the spectra and the α/ß misclassification.

11.
Radiat Prot Dosimetry ; 173(1-3): 55-62, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27885091

RESUMO

Radiological protection is a matter of concern for members of the public and thus national authorities are more likely to trust the quality of radioactivity data provided by accredited laboratories using common standards. Normative approach based on international standards aims to ensure the accuracy or validity of the test result through calibrations and measurements traceable to the International System of Units. This approach guarantees that radioactivity test results on the same types of samples are comparable over time and space as well as between different testing laboratories. Today, testing laboratories involved in radioactivity measurement have a set of more than 150 international standards to help them perform their work. Most of them are published by the International Standardization Organization (ISO) and the International Electrotechnical Commission (IEC). This paper reviews the most essential ISO standards that give guidance to testing laboratories at different stages from sampling planning to the transmission of the test report to their customers, summarizes recent activities and achievements and present the perspectives on new standards under development by the ISO Working Groups dealing with radioactivity measurement in connection with radiological protection.


Assuntos
Exposição à Radiação , Proteção Radiológica , Meio Ambiente , Exposição Ambiental , Humanos , Laboratórios , Radioatividade , Padrões de Referência
12.
Appl Radiat Isot ; 64(10-11): 1253-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16549351

RESUMO

A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (40K, 137Cs, 232Th, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides (90Sr, 210Pb(210Po), 226Ra, 239Pu, 240Pu 241Pu). Less frequently reported radionuclides (99Tc, 129I, 228Th, 230Th and 237Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units.


Assuntos
Peixes/metabolismo , Guias como Assunto , Monitoramento de Radiação/métodos , Monitoramento de Radiação/normas , Radioisótopos/análise , Radioisótopos/normas , Padrões de Referência , Animais , Cooperação Internacional , Irlanda , Oceanos e Mares , Doses de Radiação , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
J Environ Radioact ; 151 Pt 1: 22-27, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26397746

RESUMO

Measuring the gross alpha activity in water samples is a rapid, straightforward way of determining whether the water might contain a radionuclide concentration whose consumption would imply a total indicative dose (TID) greater than some reference limit - currently set at 0.1 mSv/y in Europe. There are several methods used for such measurements. Two of them are desiccation with the salts being deposited on a planchet, and coprecipitation. The main advantage of these two methods is their ease of implementation and low cost of preparing the source to measure. However, there is considerable variability in the selection of the most suitable radioactive reference standard against which to calculate the water's gross alpha activity. The goal of this paper is to propose the most appropriate reference radionuclides to use as standards in determining gross alpha activities with these two methods, taking into account the natural radioactive characteristics of a wide range of waters collected at different points in Spain. Thus, the results will be consistent with each other and representative of the sum of alpha activities of all the alpha-emitters contained in a sample.


Assuntos
Partículas alfa , Água Doce/análise , Monitoramento de Radiação/métodos , Radioisótopos/análise , Calibragem , Radioatividade , Valores de Referência , Espanha
14.
Clin Nutr ; 35(6): 1301-1307, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-26968967

RESUMO

BACKGROUND: Long-chain polyunsaturated fatty acids (LCPUFA), particularly n-3 LCPUFA, play a central role in neuronal growth and the development of the human brain. Fish is the main dietary source of n-3 LCPUFA. To assess the relation between fish consumption, estimated dietary n-3 LCPUFA intake and cognition and behaviour in childhood in a multi-centre European sample. METHODS: Children from 2 European studies, CHOP and NUHEAL, were assessed at 8 and 7.5 years of age, respectively. Different outcomes of neuropsychological development (assessed with the standardized NUTRIMENTHE Neuropsychological Battery (NNB) consisting of 15 subtests) were related with outcomes from a food-frequency questionnaire (FFQ) focussing on the consumption of fish. RESULTS: A total of 584 children completed the FFQ and the neuropsychological tests. We found no associations with calculated DHA or EPA intakes for any of the neuropsychological domains. Children who consumed 2 fish meals per week including one of fatty fish, showed no substantive differences in the cognitive domains from the children who did not. However negative associations with fatty fish consumption were found for social problems (p = 0.019), attention problems (p = 0.012), rule-breaking problems (p = 0.019) and aggressive behaviour problems (p = 0.032). No association was observed with internalizing problems. Higher levels of externalizing problems (p = 0.018) and total problems (p = 0.018) were associated with eating less fatty fish. CONCLUSIONS: Children who consumed 2 fish meals per week including one of fatty fish were less likely to show emotional and behavioural problems than those who did not.


Assuntos
Encéfalo/crescimento & desenvolvimento , Dieta , Peixes , Alimentos Marinhos , Animais , Criança , Comportamento Infantil , Cognição , Estudos Transversais , Europa (Continente) , Ácidos Graxos Ômega-3/administração & dosagem , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Comportamento Problema
15.
Appl Radiat Isot ; 109: 101-104, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26631455

RESUMO

The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified radionuclides include: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training.


Assuntos
Sedimentos Geológicos/análise , Radioisótopos/análise , Radioisótopos/normas , Radiometria/normas , Poluentes Radioativos do Solo/análise , Poluentes Radioativos do Solo/normas , Certificação/normas , Sedimentos Geológicos/química , Micronésia , Oceano Pacífico , Radioisótopos/química , Valores de Referência , Poluentes Radioativos do Solo/química
16.
J Environ Radioact ; 59(1): 113-25, 2002.
Artigo em Inglês | MEDLINE | ID: mdl-11848148

RESUMO

A rapid method for the determination of 90Sr in the presence of 137Cs using the Cherenkov radiation technique is described. The contribution of 137Cs to gross Cherenkov radiation (90Y + 137Cs) was examined for 137Cs /90Sr ratios ranging from 0.09 to 2.50 for 137Cs activities ranging from 2 to 1,211 Bq. Results from direct Cherenkov radiation measurement and results after radiochemical separation of 90Y from 90Sr for samples containing both 90Sr and 137Cs were compared. Errors below 5% were obtained for 137Cs /90Sr ratios lower than 1, when no separation was performed, independently of the activity level. However, errors between 10% and 35% were obtained for 137Cs/90Sr ratios higher than 1. In order to determine 90Sr activity in the presence of 137Cs using the Cherenkov technique, a multiple linear regression analysis model was established to correct the data for 137Cs content. The mathematical correction proposed was validated using 66 artificially contaminated lettuce samples in a laboratory experiment by taking into account the activity levels of 137Cs and 90Sr and the radionuclide ratios. Comparison of mathematically corrected radionuclide ratios with the results obtained without correction shows that, for radionuclide ratios higher than 1, error values for measuring 90Sr activity using the mathematical model were much smaller than when no radiochemical separation was performed. On the other hand, for ratios lower than 1, error values when measuring 90Sr activity with radiochemical separation were smaller than when mathematical correction was performed. In spite of this, the mathematical correction is an appropriate way of reducing the time needed to determine radiostrontium using the Cherenkov radiation technique. The method proposed could be a powerful tool for environmental research whenever the contents of 90Sr and 137Cs have to be determined.


Assuntos
Modelos Teóricos , Poluentes Radioativos/análise , Radioisótopos de Césio/análise , Monitoramento Ambiental/métodos , Sensibilidade e Especificidade , Radioisótopos de Estrôncio/análise , Fatores de Tempo
17.
Appl Radiat Isot ; 87: 468-74, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24291528

RESUMO

A Certified Reference Material (CRM) for radionuclides in seaweed (Fucus vesiculosus) from the Baltic Sea (IAEA-446) is described and the results of the certification process are presented. The (40)K, (137)Cs, (234)U and (239+240)Pu radionuclides were certified for this material, and information values for 12 other radionuclides ((90)Sr, (99)Tc, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (230)Th, (232)Th, (235)U, (238)U, (239)Pu and (240)Pu) are presented. The CRM can be used for Quality Assurance/Quality Control of analysis of radionuclides in seaweed and other biota samples, as well as for development and validation of analytical methods, and for training purposes.


Assuntos
Alga Marinha/química , Poluentes Radioativos da Água/análise , Países Bálticos , Padrões de Referência , Poluentes Radioativos da Água/normas
18.
J Environ Radioact ; 125: 56-60, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23415246

RESUMO

The determination of gross alpha, gross beta and (226)Ra activity in natural waters is useful in a wide range of environmental studies. Furthermore, gross alpha and gross beta parameters are included in international legislation on the quality of drinking water [Council Directive 98/83/EC]. In this work, a low-background liquid scintillation counter (Wallac, Quantulus 1220) was used to simultaneously determine gross alpha, gross beta and (226)Ra activity in natural water samples. Sample preparation involved evaporation to remove (222)Rn and its short-lived decay daughters. The evaporation process concentrated the sample ten-fold. Afterwards, a sample aliquot of 8 mL was mixed with 12 mL of Ultima Gold AB scintillation cocktail in low-diffusion vials. In this study, a theoretical mathematical model based on secular equilibrium conditions between (226)Ra and its short-lived decay daughters is presented. The proposed model makes it possible to determine (226)Ra activity from two measurements. These measurements also allow determining gross alpha and gross beta simultaneously. To validate the proposed model, spiked samples with different activity levels for each parameter were analysed. Additionally, to evaluate the model's applicability in natural water, eight natural water samples from different parts of Spain were analysed. The eight natural water samples were also characterised by alpha spectrometry for the naturally occurring isotopes of uranium ((234)U, (235)U and (238)U), radium ((224)Ra and (226)Ra), (210)Po and (232)Th. The results for gross alpha and (226)Ra activity were compared with alpha spectrometry characterization, and an acceptable concordance was obtained.


Assuntos
Partículas alfa , Partículas beta , Modelos Teóricos , Rádio (Elemento)/análise , Poluentes Radioativos da Água/análise , Monitoramento de Radiação , Reprodutibilidade dos Testes , Contagem de Cintilação/métodos , Espanha
19.
Appl Radiat Isot ; 81: 21-5, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23647847

RESUMO

Water is vital to humans and each of us needs at least 1.5L of safe water a day to drink. Beginning as long ago as 1958 the World Health Organization (WHO) has published guidelines to help ensure water is safe to drink. Focused from the start on monitoring radionuclides in water, and continually cooperating with WHO, the International Standardization Organization (ISO) has been publishing standards on radioactivity test methods since 1978. As reliable, comparable and 'fit for purpose' results are an essential requirement for any public health decision based on radioactivity measurements, international standards of tested and validated radionuclide test methods are an important tool for production of such measurements. This paper presents the ISO standards already published that could be used as normative references by testing laboratories in charge of radioactivity monitoring of drinking water as well as those currently under drafting and the prospect of standardized fast test methods in response to a nuclear accident.


Assuntos
Água Potável/análise , Água Potável/normas , Guias como Assunto , Monitoramento de Radiação/métodos , Monitoramento de Radiação/normas , Poluentes Radioativos da Água/análise , Poluentes Radioativos da Água/normas , Fidelidade a Diretrizes , Internacionalidade
20.
J Environ Radioact ; 118: 1-8, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23220539

RESUMO

The aim of the present work was to compare the results obtained with gross alpha methods such as evaporation, co-precipitation and total evaporation by liquid scintillation counting and to check whether these results are representative of the real total alpha activity concentration on the sample. The study was carried out on eight natural waters with very different radioactive characteristics. For all the samples uranium ((238)U, (235)U, and (234)U), radium ((226)Ra and (224)Ra), (210)Po, and (232)Th isotopes were also assayed by using radiochemical separation and alpha spectrometry in order to determine the sum of the activities of these alpha emitters. Precision (expressed as relative standard deviation) was below 28% for evaporation and below 18% for co-precipitation. In the case of total by liquid scintillation counting it was below 10% for samples with Total Alpha activity above 0.1 Bq/L (this value is about three times the MDA). Furthermore, for most of the studied waters, the Total Alpha activity and the gross alpha activity determined by the three methods were comparable. The obtained bias by the evaporation, co-precipitation, and total evaporation by liquid scintillation counting methods was lower than 40%, 25% and 20%, respectively. The ANOVA test was applied to find out if there was significant variability among the methods. For the samples with the most common radiochemical characteristics there were no significant differences among the three studied methods. However differences were detected for samples with a high saline content or with a very low activity level.


Assuntos
Poluentes Radioativos da Água/análise , Rádio (Elemento)/análise , Contagem de Cintilação , Análise Espectral , Urânio/análise
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