Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 136
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
J Environ Manage ; 128: 173-81, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23747368

RESUMO

Organotin compounds (OTs) are exclusively anthropogenic and have been widely used for their biocidal properties and as stabilizers in various industrial applications. Hence organotins are common pollutants. Their high toxicity has led to their entry on the EU water framework's priority substances' list. However, few studies are available regarding their behaviour in surface waters, in particular, in intermittent Mediterranean rivers. The Vène is an intermittent river located in Languedoc-Roussillon, southern France. It is the main tributary of an important shellfish farming site: the Thau lagoon. The present study aims at establishing the presence of OTs on a 1.5 km long reach of the river into which a waste water treatment plant (WWTP) discharges. The study is carried out during steady-state flow conditions over two consecutive years and investigates potential OTs sources in everyday domestic activities. Routine field monitoring was carried out over a 5 month period during the springs of 2008 and 2009. The results establish the presence of butyltins and octyltins throughout the 1.5 km long reach at concentrations exceeding the maximum allowable concentration levels imposed by the water framework directive. The WWTP is recognized as an important OTs point source; however, using trace and rare earth elements as tracers, an urban stormwater sewage gutter is identified as a secondary source. Its impact on the river's pollutant loads is however variable in time because of flow intermittency. The paper discusses the need for specific monitoring and management schemes for intermittent rivers.


Assuntos
Compostos Orgânicos de Estanho/análise , Rios/química , Poluentes Químicos da Água/análise , Biodegradação Ambiental , Monitoramento Ambiental/métodos , França , Análise Espaço-Temporal , Eliminação de Resíduos Líquidos
2.
Environ Pollut ; 304: 119192, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35318068

RESUMO

In recent decades, stormwater management has developed to allow stormwater to infiltrate directly into the soils instead of being collected and routed to sewer systems. However, during infiltration, stormwater creates a sediment deposit at the soil surface as the result of high loads of suspended particles (including pollutants), leading to the settlement of sedimentary layers prone to colonization by plants and earthworms. This study aims to investigate the earthworm communities of a peculiar infiltration basin and investigate the influence of edaphic conditions (water content, organic matter content, pH, height of sediment) and of persistent organic pollutants (POPs: PCBs, PCDDs and PCDFs) on these earthworms. Attention was paid to their age (juveniles or adults) and their functional group (epigeic, endogeic, anecic). We found that the earthworm abundance was mostly driven by edaphic conditions, with only a slight impact of POPs, with a significant negative impact of PCBDLno for juveniles and endogeic, and PCDDs for epigeic. On the contrary, the height of the sediment and the water content are beneficial for their presence and reproduction. Furthermore, POPs contents are also linked to physicochemical parameters of the sediment. Bioaccumulation was clearly revealed in the studied site but does not differ between juveniles and adults, except for PCDDs. Conversely, BAF values seemed to vary between functional groups, except for PCBDL non-ortho. It strongly varies with the family types (PCBs versus PCCD/Fs) and between congeners within the same family, with specific strong bioaccumulation for a few congeners.


Assuntos
Oligoquetos , Bifenilos Policlorados , Dibenzodioxinas Policloradas , Poluentes do Solo , Animais , Poluentes Orgânicos Persistentes , Bifenilos Policlorados/análise , Dibenzodioxinas Policloradas/análise , Solo , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Água
3.
Chemosphere ; 293: 133615, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35038446

RESUMO

This study explored the complementarity between targeted (TS) and non-targeted screening (NTS) based on liquid and gas-phase chromatography coupled to (high-resolution) mass spectrometry (LC-/GC-(HR)MS) for the comprehensive characterization of organohalogen fingerprints within a set of Lake Ontario lake trout samples. The concentrations of 86 legacy, emerging and novel halogenated compounds (HCs), were determined through 4 TS approaches involving no less than 6 hyphenated systems. In parallel, an innovative NTS strategy, involving both LC and GC-Q-Orbitrap, was implemented to specifically highlight halogenated signals. Non-targeted HRMS data were processed under the HaloSeeker software based on Cl and Br isotopic ratio and mass defect to extend the screening to unsuspected and unknown HCs. A total of 195 halogenated mass spectral features were characterized in the Lake Ontario lake trout, including well known HCs (PCBs, PBDEs, PBBs, DDT and their degradation products), emerging HCs (novel brominated flame retardants, short-, medium- and long-chain chlorinated paraffins) or suggested molecular formula (mainly polychlorinated ones). Among the 122 HCs highlighted by TS, only 21 were identified by NTS. These results fueled a discussion on the potential and limitations of both approaches, and the current position of NTS within environmental and health monitoring programs.


Assuntos
Monitoramento Ambiental , Retardadores de Chama , Monitoramento Ambiental/métodos , Retardadores de Chama/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Éteres Difenil Halogenados/análise , Espectrometria de Massas , Poluentes Orgânicos Persistentes
4.
Poult Sci ; 90(6): 1358-63, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21597079

RESUMO

This study deals with the transfer of melamine from poultry feed to certain poultry products, such as eggs and meat destined for human consumption. The tested amounts were, respectively, 50 and 500 mg of melamine/kg of feed. The addition of melamine had no significant effect on feed consumption and egg production. However, melamine appeared in the eggs as early as the first day of exposure. The average concentration was reached after the third day at both levels of contamination. The amounts of melamine found in eggs and tissues were almost directly proportional to the quantities ingested. However, melamine did not appear to accumulate in the organs and tissues that were studied.


Assuntos
Ração Animal/análise , Ovos/análise , Contaminação de Alimentos , Músculo Esquelético/química , Triazinas/metabolismo , Animais , Galinhas , Dieta/veterinária , Fezes/química , Feminino , Músculo Esquelético/metabolismo
5.
Animal ; 14(6): 1313-1321, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31931892

RESUMO

Brominated flame retardants (BFR) are primarily used as flame retardant additives in insulating materials. These lipophilic compounds can bioaccumulate in animal tissues, leading to human exposure via food ingestion. Although their concentration in food is not yet regulated, several of these products are recognised as persistent organic pollutants; they are thought to act as endocrine disruptors. The present study aimed to characterise the occurrence of two families of BFRs (hexabromocyclododecane (HBCDD) and polybrominated diphenyl ethers (PBDE)) in hen eggs and broiler or pig meat in relation to their rearing environments. Epidemiological studies were carried out on 60 hen egg farms (34 without an open-air range, 26 free-range), 57 broiler farms (27 without an open-air range, 30 free-range) and 42 pig farms without an open-air range in France from 2013 to 2015. For each farm, composite samples from either 12 eggs, five broiler pectoral muscles or three pig tenderloins were obtained. Eight PBDE congeners and three HBCDD stereoisomers were quantified in product fat using gas chromatography-high-resolution mass spectrometry, or high-performance liquid chromatography-tandem mass spectrometry, respectively. The frequencies of PBDE detection were 28% for eggs (median concentration 0.278 ng/g fat), 72% for broiler muscle (0.392 ng/g fat) and 49% for pig muscle (0.403 ng/g fat). At least one HBCDD stereoisomer was detected in 17% of eggs (0.526 ng/g fat), 46% of broiler muscle (0.799 ng/g fat) and 36% of pig muscle (0.616 ng/g fat). Results were similar in concentration to those obtained in French surveillance surveys from 2012 to 2016. Nevertheless, the contamination of free-range eggs and broilers was found to be more frequent than that of conventional ones, suggesting that access to an open-air range could be an additional source of exposure to BFRs for animals. However, the concentration of BFRs in all products remained generally very low. No direct relationship could be established between the occurrence of BFRs in eggs and meat and the characteristics of farm buildings (age, building materials). The potential presence of BFRs in insulating materials is not likely to constitute a significant source of animal exposure as long as the animals do not have direct access to these materials.


Assuntos
Monitoramento Ambiental/métodos , Retardadores de Chama/análise , Carne/análise , Agricultura , Animais , Galinhas , Poluentes Ambientais/química , Fazendas , França , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Suínos
6.
Biotechnol Bioeng ; 103(4): 687-95, 2009 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-19301412

RESUMO

It was observed that a biocatalyst prepared from dehydrated whole cells of a recombinant Escherichia coli (initially suspended in borate buffer) was able to hydrolyze gaseous 1-chlorobutane in a solid/gas reactor. Nevertheless, at 40 degrees C and for a 0.7 water activity, it rapidly lost its activity. The explanation of this phenomenon was first investigated by observing the biocatalyst structure at the microscopic level and by studying the localization of the dehalogenase involved in catalysis (intracellular/extracellular). The behavior of this biocatalyst was then compared with that of a preparation made from cells extracts. The reasons of the inactivation are discussed in terms of thermal denaturation and protective effect of buffer salts.


Assuntos
Butanos/metabolismo , Enzimas/metabolismo , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Halogênios/metabolismo , Estabilidade Enzimática
7.
J Chromatogr A ; 1601: 232-242, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31097297

RESUMO

With the objectives of both generating bisphenols (BPs) conjugates occurrence data in food from animal origin but also investigating the origin of associated contamination, the present study deals with the development of an efficient analytical method aiming at monitoring both BPA and BPS conjugated metabolites in food from animal origin. The objective of such monitoring is to determine the origin of BPs contamination (FCM or animal contamination). The targeted compounds were BPA-monoglucuronide (BPA-1G), BPA-diglucuronide (BPA-2G), BPA-monosulfate (BPA-1S), BPA-disulfate (BPA-2S) and BPS-monoglucuronide (BPS-1G). The developed standard operating procedure includes a preliminary solid-liquid extraction step followed by two successive solid phase extraction (SPE) stages, using successively a non-polar phase and a strong cation exchange polymer. Quantification was achieved according to both the isotopic dilution and surrogated quantification methods, using 13C-BPA-1G and BPA-d6-1S as internal standards. Linearity was validated (R2 > 0.99) for each molecule within the concentration range [0-10] µg kg-1. Detection limits ranged from 0.02 µg kg-1 (BPA-1G in muscle, BPA-1S and BPA-2G in liver) to 0.50 µg kg-1 (BPA-2S in muscle). The strategy was then proven on liver samples collected from pregnant ewes subcutaneously exposed to BPA during 105 days, at 50 µg kg-1 per day. BPA-1G, BPA-2G and BPA-1S were detected and quantified at a concentration of 3.81 µg kg-1, 0.80 µg kg-1 and 0.09 µg kg-1, respectively. The analytical method was finally implemented on fifty unpacked food samples from animal origin in which significant free BPA concentrations were previously measured. Since no metabolites of BPA could be measured (

Assuntos
Compostos Benzidrílicos/análise , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Fenóis/análise , Sulfonas/análise , Espectrometria de Massas em Tandem , Animais , Compostos Benzidrílicos/metabolismo , Feminino , Contaminação de Alimentos/análise , Glucuronídeos/análise , Limite de Detecção , Fenóis/metabolismo , Gravidez , Ovinos , Extração em Fase Sólida , Sulfonas/metabolismo , Ésteres do Ácido Sulfúrico/análise
8.
Cancer Radiother ; 23(6-7): 572-575, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31422001

RESUMO

Along with the surgeon, the gastroenterologist and the general practitioner, the radiation oncologist is involved in the follow-up of patients with rectal cancer treated by radiation. Post-treatment follow-up is recommended by major professional expert groups and consists of clinical examination, monitoring of carcinoembryonic antigen, colonoscopy and computed tomography of the abdomen and pelvis. Three recent large phase III randomized trials demonstrated a lack of survival benefit from intensive follow-up strategies in comparison with minimal follow-up. However, a follow-up program is not only important for the detection of an early disease relapse but it can be also used for the identification and the management of long-term toxicity and sequalae related to rectal cancer treatment.


Assuntos
Assistência ao Convalescente/métodos , Recidiva Local de Neoplasia/diagnóstico , Segunda Neoplasia Primária/prevenção & controle , Papel do Médico , Radio-Oncologistas , Neoplasias Retais/diagnóstico , Neoplasias Retais/radioterapia , Ensaios Clínicos Fase III como Assunto , Feminino , Seguimentos , Humanos , Masculino , Ensaios Clínicos Controlados Aleatórios como Assunto
9.
PLoS One ; 14(5): e0216223, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31071155

RESUMO

Satellite telemetry is an increasingly utilized technology in wildlife research, and current devices can track individual animal movements at unprecedented spatial and temporal resolutions. However, as we enter the golden age of satellite telemetry, we need an in-depth understanding of the main technological, species-specific and environmental factors that determine the success and failure of satellite tracking devices across species and habitats. Here, we assess the relative influence of such factors on the ability of satellite telemetry units to provide the expected amount and quality of data by analyzing data from over 3,000 devices deployed on 62 terrestrial species in 167 projects worldwide. We evaluate the success rate in obtaining GPS fixes as well as in transferring these fixes to the user and we evaluate failure rates. Average fix success and data transfer rates were high and were generally better predicted by species and unit characteristics, while environmental characteristics influenced the variability of performance. However, 48% of the unit deployments ended prematurely, half of them due to technical failure. Nonetheless, this study shows that the performance of satellite telemetry applications has shown improvements over time, and based on our findings, we provide further recommendations for both users and manufacturers.


Assuntos
Animais Selvagens/fisiologia , Ecossistema , Monitoramento Ambiental , Sistemas de Informação Geográfica , Astronave , Telemetria , Animais
10.
Chemosphere ; 207: 497-506, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29843025

RESUMO

Determination of the occurrence levels of legacy and novel BFRs is today required to better understand the trends of BFRs contamination in food consecutive to the EU PBDEs restrictions and to proceed to a recent human food exposure in parallel. Therefore, concentrations of a large set of brominated flame retardants (BFRs) (n = 27) including PBDEs, HBCDDs, TBBPA and novel flame retardants (nBFRs) have been determined in more than 600 food and feed samples collected between 2014 and 2016 in the context of French monitoring plans. Although legacy BFRs had already been studied in France, such a survey constituted the very first determination of nBFRs occurrence in foodstuffs at the national level. The concentration levels measured in fish and fish products were in general higher than in the other food categories. PBDEs were detected in 70% of the samples and were observed as the most abundant congeners (representing 80% of the sum of the monitored BFRs), while α-HBCDD could also be considered as a predominant congener (up to 26% of the sum of the monitored BFRs in fishes). nBFRs concentration levels were most of the time below the LOQ, except PBT, PBBz and HBBz which were more frequently detected at low levels. Also investigated in the study, BRPs exhibited high concentration levels in crustaceous (maximum value > 2700 pg/g ww).


Assuntos
Ração Animal/análise , Peixes/metabolismo , Retardadores de Chama/análise , Análise de Alimentos/métodos , Hidrocarbonetos Bromados/análise , Animais , França , Halogenação , Humanos , Fatores de Tempo
11.
Eur Ann Otorhinolaryngol Head Neck Dis ; 134(4): 259-264, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28416263

RESUMO

To analyze the medical literature devoted to work-up, epidemiology, local control, survival, complications and sequelae after conservative treatment for early-stage squamous cell carcinoma of the tonsillar region. An analysis of the PubMed (1975-2016) database was performed using the following keywords and associations: "tonsil/tonsillar region/oropharynx" AND "squamous cell carcinoma" AND "early-stage (I-II; T1-2N0M0)" AND "radiation therapy/radiotherapy" OR "conservative surgery/oropharyngectomy/transoral surgery/radical tonsillectomy". The search retrieved 10 retrospective series documenting local control and/or survival in series with more than 50 cases and a minimum 2 years' follow-up after conservative treatment; no prospective studies, meta-analyses and/or Cochrane analyses were found. Magnetic resonance imaging is the key radiological exam for local extension assessment. Human papilloma virus infection (HPV) is a risk factor that must be screened for systematically, since it induces tumoral radio-sensitivity and increases the risk of specific synchronous and metachronous second primaries. Whatever conservative treatment used, local control and survival rates higher than 85% were achieved. Implementing intensity-modulated radiation therapy reduced the incidence and severity of radiation-related complications and sequelae. Transoral surgery yielded very low morbidity/mortality rates, enabled association to ipsilateral neck dissection, and allowed radiation therapy to be reserved for the management of metachronous second primaries. Transoral surgery appeared to be the first-line option in the majority of cases. Lifetime follow-up adapted to HPV status is mandatory. The development of HPV vaccination does not mean that campaigns against smoking and alcohol abuse are of diminished importance.


Assuntos
Carcinoma de Células Escamosas/radioterapia , Carcinoma de Células Escamosas/cirurgia , Neoplasias Tonsilares/radioterapia , Neoplasias Tonsilares/cirurgia , Tonsilectomia , Carcinoma de Células Escamosas/diagnóstico , Tratamento Conservador/métodos , Detecção Precoce de Câncer , Medicina Baseada em Evidências , Humanos , Estadiamento de Neoplasias , Neoplasias Tonsilares/diagnóstico , Tonsilectomia/métodos , Resultado do Tratamento
12.
Brachytherapy ; 16(3): 518-525, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28262516

RESUMO

PURPOSE: There are only scarce data on the place of brachytherapy (BT) for treatment of vulvar carcinoma. Our institutional experience of interstitial BT for vulvar carcinoma patients is reported. METHODS AND MATERIALS: Clinical records of patients receiving low-dose-rate or pulsed-dose-rate BT as part of the primary treatment for primary/recurrent vulvar squamous cell carcinoma or as part of postoperative treatment between 2000 and 2015 were included. Patients, tumors, and treatment characteristics as well as clinical outcome were examined. RESULTS: A total of 26 patients treated with BT were identified. BT was delivered as part of primary intent treatment for locally advanced/recurrent cancer in 11 patients and as part of postoperative treatment in 15 patients. Median age at time of BT was 63 years (range, 41-88 years). Pulsed-dose-rate and low-dose-rate were used in 15 patients and 11 patients, respectively. BT was performed as a boost to the tumor bed following external beam radiotherapy (n = 13) or as the sole irradiation modality (n = 13). Total median dose at the level of primary tumor was 60 GyEQD2 (range, 55-60 GyEQD2). With mean followup of 41 months (range, 5 months-11.3 years), 11 patients experienced tumor relapse, and in two of them, site of relapse was only local. Three-year estimated disease-free survival and overall survival rates were 57% (95% confidence interval: 45-69%) and 81% (95% confidence interval: 72-90%), respectively. All toxicities were Grade 2 or less. CONCLUSIONS: Interstitial BT used as part of the primary or postoperative treatment of vulvar carcinoma is feasible with a satisfactory toxicity profile. Prognosis remains, however, dismal, with a high frequency of failures in patients with locally advanced tumors.


Assuntos
Braquiterapia , Carcinoma de Células Escamosas/radioterapia , Recidiva Local de Neoplasia/radioterapia , Neoplasias Vulvares/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Braquiterapia/efeitos adversos , Braquiterapia/métodos , Carcinoma de Células Escamosas/secundário , Carcinoma de Células Escamosas/cirurgia , Tratamento Conservador , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/cirurgia , Dosagem Radioterapêutica , Taxa de Sobrevida , Neoplasias Vulvares/patologia , Neoplasias Vulvares/cirurgia
13.
Chemosphere ; 144: 2497-506, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26624956

RESUMO

The aim of this study was to investigate the fate and behaviour of butyltin pollutants, including monobutyltin (MBT), dibutylin (DBT), and tributyltin (TBT), in waste stabilisation ponds (WSP). The study was conducted as part of a baseline survey and included five sampling campaigns comprising bottom sludge and the water column from each pond from a typical WSP in France. Butyltins were detected in all raw wastewater and effluents, reflecting their widespread use. Our results revealed high affinity between butyltins and particulate matter and high accumulation of butyltins in the sludge taken from anaerobic ponds. The dissolved butyltins in the influent ranged from 21.5 to 28.1 ng(Sn).L(-1) and in the effluent, from 8.8 to 29.3 ng(Sn).L(-1). The butyltin concentrations in the sludge ranged from 45.1 to 164 and 3.6-8.1 ng(Sn).g(-1) respectively in the first and last ponds. Our results showed an average treatment efficiency of 71% for MBT, 47% for DBT, 55% for TBT. Laboratory sorption experiments enabled the calculation of a distribution coefficient (Kd = 75,000 L.kg-1) between TBT and particulate matter from the WSPs. The Kd explained the accumulation and persistence of the TBT in the sludge after settling of particulate matter. The continuous supply of contaminated raw wastewater and the sorption-desorption processes in the ponds led to incomplete bio- and photolytic degradation and to the persistence of butyltins in dissolved and particulate matrices throughout the survey period. It is thus recommended to use shallow ponds and to pay particular attention when sludge is used for soil amendment.


Assuntos
Compostos Orgânicos de Estanho/análise , Compostos de Trialquitina/análise , Águas Residuárias/análise , Poluentes Químicos da Água/análise , França , Lagoas , Eliminação de Resíduos Líquidos
14.
Diagn Interv Imaging ; 97(7-8): 823-37, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27017095

RESUMO

On sagittal images after anterior cruciate ligament (ACL) reconstructions, the femoral tunnel aperture should be at the junction of the line drawn along the posterior femoral cortex and the line drawn along the roof of the intercondylar notch (Bluemensaat line). The tibial tunnel aperture should be in the anterior portion of the second third, i.e. anterior aspect of the middle of the tibial epiphysis. An inaccurate placement of the femoral tunnel affects the graft isometry. A tibial tunnel too anteriorly placed results in intercondylar notch roof impingement. After meniscus surgery, first-line MRI is often sufficient to diagnose new tears; however, sometimes it is necessary to perform CT arthrography or MR arthrography. Surgical cartilage repair is evaluated based on articular congruity and on the appearance of the subchondral bone.


Assuntos
Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/cirurgia , Reconstrução do Ligamento Cruzado Anterior/efeitos adversos , Reconstrução do Ligamento Cruzado Anterior/métodos , Artroplastia Subcondral , Transplante Ósseo , Enxerto Osso-Tendão Patelar-Osso , Cartilagem/transplante , Cartilagem Articular/diagnóstico por imagem , Cartilagem Articular/lesões , Cartilagem Articular/cirurgia , Fibrose/diagnóstico por imagem , Fraturas de Cartilagem/diagnóstico por imagem , Fraturas de Cartilagem/cirurgia , Humanos , Articulação do Joelho/patologia , Meniscos Tibiais/diagnóstico por imagem , Meniscos Tibiais/cirurgia , Complicações Pós-Operatórias/diagnóstico por imagem , Tendões/transplante
15.
J Chromatogr A ; 1459: 120-128, 2016 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-27425757

RESUMO

A gas chromatography tandem mass spectrometry method using atmospheric pressure chemical ionisation was developed for the monitoring of 16 brominated flame retardants (7 usually monitored polybromodiphenylethers (PBDEs) and BDE #209 and 8 additional emerging and novel BFRs) in food and feed of animal origin. The developed analytical method has decreased the run time by three compared to conventional strategies, using a 2.5m column length (5% phenyl stationary phase, 0.1mm i.d., 0.1µmf.t.), a pulsed split injection (1:5) with carrier gas helium flow rate at 0.48mLmin(-1) in one run of 20 min. For most BFRs, analytical data were compared with the current analytical strategy relying on GC/EI/HRMS (double sector, R=10000 at 10% valley). Performances in terms of sensitivity were found to meet the Commission recommendation (118/2014/EC) for nBFRs. GC/APCI/MS/MS represents a promising alternative for multi-BFRs analysis in complex matrices, in that it allows the monitoring of a wider list of contaminants in a single injection and a shorter run time.


Assuntos
Ração Animal/análise , Retardadores de Chama/análise , Análise de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Animais , Pressão Atmosférica , Retardadores de Chama/normas , Cromatografia Gasosa-Espectrometria de Massas/normas , Éteres Difenil Halogenados , Halogenação , Hélio/química , Íons/química , Controle de Qualidade
16.
Environ Pollut ; 218: 728-738, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27521295

RESUMO

The present study compares concentrations and chemical profiles of an extended range of persistent organic pollutants (dioxins, polychlorobiphenyls, brominated flame retardants and organochlorine pesticides) in breast milk samples from French (n = 96), Danish (n = 438) and Finnish (n = 22) women. Median exposure levels observed in French women (WHO-TEQ2005 PCDD/F = 6.1 pg/g l.w., WHO-TEQ2005 dl-PCB = 4.3 pg/g l.w., sum of 6 ndl-PCB = 85.2 ng/g l.w., sum of 7 i-PBDE = 1.5 ng/g l.w.) appeared overall lower than in Danish and Finnish women for all examined POPs, except for α-HBCD (2-fold higher level at 0.6 ng/g l.w.). Furthermore, the observed exposure levels of dioxins and PCBs were higher in Danish women (WHO-TEQ2005 PCDD/F = 13.2 pg/g l.w., WHO-TEQ2005 dl-PCB = 6.6 pg/g l.w., sum of 6 ndl-PCB = 162.8 ng/g l.w.) compared to Finnish women (WHO-TEQ2005 PCDD/F = 9.0 pg/g l.w., WHO-TEQ2005 dl-PCB = 4.6 pg/g l.w., sum of 6 ndl-PCB = 104.0 ng/g l.w.), whereas the concentrations of PBDEs were similar for Danish and Finnish women (sum of 7 i-PBDE = 4.9 and 5.2 ng/g l.w. respectively). The organochlorine (OC) pesticide contamination profile, determined in a subset of French samples, was dominated by p,p'-DDE (56.6%), followed by ß-HCH (14.2%), HCB (9.7%) and dieldrin (5.2%), while other compounds were only minor contributors (<5%). The three countries appeared to be discriminated by the observed contamination patterns of the PCDD/F versus PCB, and the 1,2,3,6,7,8-HxCDD versus 1,2,3,4,7,8-HxCDD ratios, in addition to the relative contributions of specific congeners to the contamination profile (PCBs #118 and #156, PBDEs #28, #47, #99 and #153). In conclusion, unique chemical signatures were observed for each country on the basis of some POP congeners. Future biomonitoring studies will need to consider the high variability of individual exposure profiles in relation to multiple exposure sources but also physiological and metabolic differences.


Assuntos
Poluentes Ambientais/química , Retardadores de Chama/análise , Leite Humano/química , Praguicidas/química , Bifenilos Policlorados/química , Adulto , Animais , Dinamarca , Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Feminino , Finlândia , França , Éteres Difenil Halogenados/análise , Humanos , Hidrocarbonetos Clorados/análise , Praguicidas/metabolismo
17.
Leukemia ; 1(5): 463-5, 1987 May.
Artigo em Inglês | MEDLINE | ID: mdl-2823023

RESUMO

Bovine leukemia virus (BLV) is experimentally infectious for sheep. Virus production does not occur in the animals, but only after in vitro cultivation of infected lymphocytes in the presence of phytohemagglutinin. Lipopolysaccharide or dextran sulfate 500 had no effect. After panning separation, it was possible to demonstrate that, in peripheral blood lymphocytes, BLV was integrated in the B lymphocytes only and that BLV expression took place in a fraction of this population. The ovine leukemia may constitute a good experimental model for understanding the virus-induced leukemias of the BLV-human T cell leukemia virus group.


Assuntos
Linfócitos B/microbiologia , Vírus da Leucemia Bovina/crescimento & desenvolvimento , Retroviridae/crescimento & desenvolvimento , Ovinos/microbiologia , Animais , Antígenos Virais/análise , Linfócitos B/imunologia , DNA Viral/análise , Vírus da Leucemia Bovina/imunologia , Ativação Linfocitária , Receptores de Antígenos de Linfócitos B/análise , Especificidade da Espécie
18.
J Agric Food Chem ; 53(13): 5336-41, 2005 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-15969515

RESUMO

The systemic imidacloprid is one of the most used insecticides in the world for field and horticultural crops. This neurotoxicant is often used as seed-dressing, especially for maize, sunflower, and rape. Using a LC/MS/MS technique (LOQ = 1 microg/kg and LOD = 0.1 microg/kg), the presence of imidacloprid has been measured in maize from field samples at the time of pollen shed, from less than 0.1 microg/kg up to 33.6 microg/kg. Numerous random samples were collected throughout France from 2000 to 2003. The average levels of imidacloprid measured are 4.1 microg/kg in stems and leaves, 6.6 microg/kg in male flowers (panicles), and 2.1 microg/kg in pollen. These values are similar to those found previously in sunflower and rape. These results permit evaluation of the risk to honeybees by using the PEC/PNEC ratios (probable exposition concentrations/predicted no effect concentration). PEC/PNEC risk ratios were determined and ranged between 500 and 600 for honeybees foraging on maize treated with imidacloprid by seed dressing. Such a high risk factor can be related to one of the main causes of honeybee colony losses.


Assuntos
Imidazóis/metabolismo , Inseticidas/metabolismo , Zea mays/metabolismo , Flores/química , Neonicotinoides , Nitrocompostos , Folhas de Planta/química , Caules de Planta/química , Pólen/química , Zea mays/química
19.
Chemosphere ; 118: 329-35, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25463258

RESUMO

Current contamination levels of selected legacy, currently-used and emerging halogenated contaminants were monitored in marine shellfish along French coastlines. The studied contaminants included polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE), hexabromobenzene (HBB), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153) and perfluorinated compounds (PFCs).BDE-47, BDE-209, BTBPE, HBB and α-HBCDD were detected in 100% of the analyzed samples, whereas BB-153, DBDPE and PFOS were detected at frequencies of 97%, 90% and 55%, respectively. Concentrations were in the pg g−1 ww range and varied as follows: PFOS > BDE-47 ∼ α-HBCDD > BDE-209 > BTBPE ∼ DBDPE > HBB ∼ BB-153. Overall, non-PBDE Brominated Flame Retardants (BFRs) revealed concentrations between 3 and 59 times lower than those of PBDEs.PBDE pattern was dominated by BDE-47, followed by BDE-99 > BDE-100 > BDE-49 > BDE-209 > BDE-154; these 6 congeners represented 94% of the summed ten PBDEs. PFC pattern determination revealed PFOS as the predominant PFC in samples from the English Channel and Atlantic, whereas perfluorocarboxylic acids (PFCAs) prevailed in Mediterranean samples. Temporal trend investigations on archived samples from the Mediterranean coast collected between 1981 and 2012 showed a prevalence of PFOS until 1998; PFCAs subsequently increased and became more abundant than PFOS. High levels of PFCAs were observed until 2008, followed by a decrease and stabilization in 2010­2012. Amongst PFCAs, perfluorotridecanoic acid (PFTrDA) and perfluoroundecanoic acid (PFUnA) were predominant and exhibited similar time trends, suggesting similar sources at the investigated site, home to major industrial activity.


Assuntos
Crassostrea/química , Monitoramento Ambiental/métodos , Hidrocarbonetos Halogenados/análise , Mytilus edulis/química , Frutos do Mar/análise , Poluentes Químicos da Água/análise , Animais , França , Oceanos e Mares , Água do Mar/química
20.
Nanoscale ; 7(44): 18686-93, 2015 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-26497868

RESUMO

Monoclinic VO2 nanoparticles are of interest due to the material's thermochromic properties, however, direct synthesis routes to VO2 nanoparticles are often inaccessible due to the high synthesis temperatures or long reaction times required. Herein, we present a two-step synthesis route for the preparation of monoclinic VO2 nanoparticles using Continuous Hydrothermal Flow Synthesis (CHFS) followed by a short post heat treatment step. A range of particle sizes, dependent on synthesis conditions, were produced from 50 to 200 nm by varying reaction temperatures and the residence times in the process. The nanoparticles were characterised by powder X-ray diffraction, Raman and UV/Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The nanoparticles were highly crystalline with rod and sphere-like morphologies present in TEM micrographs, with the size of both the rod and spherical particles being highly dependent on both reaction temperature and residence time. SEM micrographs showed the surface of the powders produced from the CHFS process to be highly uniform. The samples were given a short post synthesis heat treatment to ensure that they were phase pure monoclinic VO2, which led to them exhibiting a large and reversible switch in optical properties (at near-IR wavelengths), which suggests that if such materials can be incorporated into coatings or in composites, they could be used for fenestration in architectural applications.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA