New exposure system to evaluate the toxicity of (scooter) exhaust emissions in lung cells in vitro

A constantly growing number of scooters produce an increasing amount of potentially harmful emissions. Due to their engine technology, two-stroke scooters emit huge amounts of adverse substances, which can induce adverse pulmonary and cardiovascular health effects. The aim of this study was to develop a system to expose a characterized triple cell coculture model of the human epithelial airway barrier, to freshly produced and characterized total scooter exhaust emissions. In exposure chambers, cell cultures were exposed for 1 and 2 h to 1:100 diluted exhaust emissions and in the reference chamber to filtered ambient air, both controlled at 5% CO(2), 85% relative humidity, and 37 degrees C. The postexposure time was 0-24 h. Cytotoxicity, used to validate the exposure system, was significantly increased in exposed cell cultures after 8 h postexposure time. (Pro-) inflammatory chemo- and cytokine concentrations in the medium of exposed cells were significantly higher at the 12 h postexposure time point. It was shown that the described exposure system (with 2 h exposure duration, 8 and 24 h postexposure time, dilution of 1:100, flow of 2 L/min as optimal exposure conditions) can be used to evaluate the toxic potential of total exhaust emissions.

Acute respiratory syndrome after inhalation of waterproofing sprays: a posteriori exposure-response assessment in 102 cases

Waterproofing agents are widely used to protect leather and textiles in both domestic and occupational activities. An outbreak of acute respiratory syndrome following exposure to waterproofing sprays occurred during the winter 2002-2003 in Switzerland. About 180 cases were reported by the Swiss Toxicological Information Centre between October 2002 and March 2003, whereas fewer than 10 cases per year had been recorded previously. The reported cases involved three brands of sprays containing a common waterproofing mixture, that had undergone a formulation change in the months preceding the outbreak. A retrospective analysis was undertaken in collaboration with the Swiss Toxicological Information Centre and the Swiss Registries for Interstitial and Orphan Lung Diseases to clarify the circumstances and possible causes of the observed health effects. Individual exposure data were generated with questionnaires and experimental emission measurements. The collected data was used to conduct numeric simulation for 102 cases of exposure. A classical two-zone model was used to assess the aerosol dispersion in the near- and far-field during spraying. The resulting assessed dose and exposure levels obtained were spread on large scales, of several orders of magnitude. No dose-response relationship was found between exposure indicators and health effects indicators (perceived severity and clinical indicators). Weak relationships were found between unspecific inflammatory response indicators (leukocytes, C-reactive protein) and the maximal exposure concentration. The results obtained disclose a high interindividual response variability and suggest that some indirect mechanism(s) predominates in the respiratory disease occurrence. Furthermore, no threshold could be found to define a safe level of exposure. These findings suggest that the improvement of environmental exposure conditions during spraying alone does not constitute a sufficient measure to prevent future outbreaks of waterproofing spray toxicity. More efficient preventive measures are needed prior to the marketing and distribution of new waterproofing agents.

Exposure of silver-nanoparticles and silver-ions to lung cells in vitro at the air-liquid interface

BACKGROUND: Due to its antibacterial properties, silver (Ag) has been used in more consumer products than any other nanomaterial so far. Despite the promising advantages posed by using Ag-nanoparticles (NPs), their interaction with mammalian systems is currently not fully understood. An exposure route via inhalation is of primary concern for humans in an occupational setting. Aim of this study was therefore to investigate the potential adverse effects of aerosolised Ag-NPs using a human epithelial airway barrier model composed of A549, monocyte derived macrophage and dendritic cells cultured in vitro at the air-liquid interface. Cell cultures were exposed to 20 nm citrate-coated Ag-NPs with a deposition of 30 and 278 ng/cm2 respectively and incubated for 4 h and 24 h. To elucidate whether any effects of Ag-NPs are due to ionic effects, Ag-Nitrate (AgNO3) solutions were aerosolised at the same molecular mass concentrations. RESULTS: Agglomerates of Ag-NPs were detected at 24 h post exposure in vesicular structures inside cells but the cellular integrity was not impaired upon Ag-NP exposures. Minimal cytotoxicity, by measuring the release of lactate dehydrogenase, could only be detected following a higher concentrated AgNO3-solution. A release of pro-inflammatory markers TNF-alpha and IL-8 was neither observed upon Ag-NP and AgNO3 exposures as well as was not affected when cells were pre-stimulated with lipopolysaccharide (LPS). Also, an induction of mRNA expression of TNF-alpha and IL-8, could only be observed for the highest AgNO3 concentration alone or even significantly increased when pre-stimulated with LPS after 4 h. However, this effect disappeared after 24 h. Furthermore, oxidative stress markers (HMOX-1, SOD-1) were expressed after 4 h in a concentration dependent manner following AgNO3 exposures only. CONCLUSIONS: With an experimental setup reflecting physiological exposure conditions in the human lung more realistic, the present study indicates that Ag-NPs do not cause adverse effects and cells were only sensitive to high Ag-ion concentrations. Chronic exposure scenarios however, are needed to reveal further insight into the fate of Ag-NPs after deposition and cell interactions.

Caracterização física e mecânica de argamassas à base de cimento Portland e cinza de casca de arroz residual

Rice husk, employed as an energy source at milling industries in Brazil generates, after burning, a dark ash. This residue is not yet conveniently disposed, being currently dumped on large areas, causing environmental problems. This research intended to evaluate the applications of residual rice husk ashes (RHA) as a partial replacement of cement for mortar production. Rice husk ash was chemically characterized through X-ray fluorescence, determination of carbon content, X-ray diffraction, and laser granulometric analysis. Mortar specimens were submitted to two different exposure conditions: internal and external environments at a maximum period of five months. Physical-mechanical testing were compressive strength and ultrasonic pulse velocity (UPV). Although presenting good mechanical performance, the mortar based on ash (RHA) did not present pozolanicity but it can be employed in cement matrices as inert material (filler).

Can Eucalyptus invade native forest fragments close to commercial stands?

Some Eucalyptus species are widely used as a plantation crop in tropical and subtropical regions. One reason for this is the diversity of end uses, but the main reason is the high level of wood production obtained from commercial plantings. With the advancement of biotechnology it will be possible to expand the geographical area in which eucalypts can be used as commercial plantation crops, especially in regions with current climatic restrictions. Despite the popularity of eucalypts and their increasing range, questions still exist, in both traditional planting areas and in the new regions: Can eucalypts invade areas of native vegetation, causing damage to natural ecosystems biodiversity? The objective of this study it was to assess whether eucalypts can invade native vegetation fragments in proximity to commercial stands, and what factors promote this invasive growth. Thus, three experiments were established in forest fragments located in three different regions of Brazil. Each experiment was composed of 40 plots (1 m(2) each one), 20 plots located at the border between the forest fragment and eucalypts plantation, and 20 plots in the interior of the forest fragments. In each experimental site, the plots were paired by two soil exposure conditions, 10 plots in natural conditions and 10 plots with soil exposure (no plant and no litter). During the rainy season, 2 g of eucalypts seeds were sown in each plot, including Eucalyptus grandis or a hybrid of E. urophylla x E. grandis, the most common commercial eucalypt species planted in the three region. At 15, 30, 45, 90, 180, 270 and 360 days after sowing, we assessed the number of seedlings of eucalypts and the number of seedlings of native species resulting from natural regeneration. Fifteen days after sowing, the greatest number of eucalypts seedlings (37 m(-2)) was observed in the plots with lower luminosity and exposed soil. Also, for native species, it was observed that exposed soil improved natural germination reaching the highest number of 163 seedlings per square meter. Site and soil exposure were the factors that have the greatest influence on seed germination of both eucalypt and native species. However, 270 days after sowing, eucalypt seedlings were not observed at any of the three experimental sites. The result shows the inability of eucalypts to adapt to condition outside of their natural range. However, native species demonstrated their strong capacity for natural regeneration in forest fragments under the same conditions where eucalypts were seeded. (C) 2011 Elsevier B.V. All rights reserved.

Effects of visuospatial tasks on desensitization to emotive memories

Objectives. Intrusive memories of extreme trauma can disrupt a stepwise approach to imaginal exposure. Concurrent tasks that load the visuospatial sketchpad (VSSP) of working memory reduce the vividness of recalled images. This study tested whether relief of distress from competing VSSP tasks during imaginal exposure is at the cost of impaired desensitization. Design. This study examined repeated exposure to emotive memories using 18 unselected undergraduates and a within-subjects design with three exposure conditions (Eye Movement, Visual Noise, Exposure Alone) in random, counterbalanced order. Method. At baseline, participants recalled positive and negative experiences, and rated the vividness and emotiveness of each image. A different positive and negative recollection was then used for each condition. Vividness and emotiveness were rated after each of eight exposure trials. At a post-exposure session 1 week later, participants rated each image without any concurrent task. Results. Consistent with previous research, vividness and distress during imaging were lower during Eye Movements than in Exposure Alone, with passive visual interference giving intermediate results. A reduction in emotional responses from Baseline to Post was of similar size for the three conditions. Conclusion. Visuospatial tasks may offer a temporary response aid for imaginal exposure without affecting desensitization.

Estudo laboratorial e em condições reais sobre o aglomerado de cortiça expandida aplicado como revestimento exterior

Trabalho Final de Mestrado elaborado no Laboratório de Engenharia Civil para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Edificações no âmbito do protocolo de cooperação entre o ISEL e o LNEC

Avaliação da eficácia de produtos inovadores de proteção da madeira para exteriores

Nesta dissertação procurou-se comparar os desempenhos de três produtos de proteção da madeira quando expostos a várias condições de degradação. Tendo em consideração a grande quantidade de variáveis quando se faz este tipo de estudos, tentou-se controlar o maior número possível destas, de modo a permitir a comparação com outros estudos que venham a ser feitos futuramente. O objetivo a longo prazo é a contribuição desta dissertação para um conjunto de resultados cada vez mais abrangente, facilitando a escolha do utilizador, quando pretender proteger a madeira das agressões exteriores com este tipo de produtos. A principal conclusão nesta dissertação é que a agressividade do meio tem um papel determinante para os resultados obtidos, bem como as condições de inclinação e orientação da madeira. Situações de má selagem de topos ou não consideração da presença agentes biológicos são outros dois fatores que influenciam a durabilidade da construção. Finalmente, concluiu-se que não existem soluções únicas, tendo que se estudar caso a caso, quais as condições exatas de exposição, de forma a escolher o produto, ou produtos, mais adequados.

Exposição profissional a chumbo : utilização da protoporfirina-zinco (PPZ) na vigilância de saúde de trabalhadores ex

Resumo Uma estratégia de avaliação e prevenção de riscos na exposição a agentes químicos deve ter sempre em conta que a vigilância do ambiente de trabalho e a da saúde dos trabalhadores são aspectos complementares de uma mesma realidade – os riscos resultantes da interacção entre um agente químico e os trabalhadores a ele expostos. Se à Vigilância Ambiental compete apreciar o risco, pela caracterização do agente no ambiente de trabalho, a Vigilância Biológica pronuncia-se sobre a interacção entre o tóxico e o organismo, avaliando a resposta à agressão química e a evolução das reacções de adaptação ou de desajuste face à absorção do tóxico. Os Indicadores Biológicos, deste modo, assumem um estatuto de instrumento privilegiado na vigilância da saúde dos trabalhadores expostos, na medida em que medem a quantidade de tóxico que efectivamente penetrou e foi absorvido, ou o resultado (efeito) determinado por essa mesma dose. O presente estudo procura contribuir para a definição de um quadro metodológico de utilização dos Indicadores Biológicos na avaliação/gestão da exposição profissional ao chumbo, designadamente apreciando a variação da protoporfirina-zinco (PPZ), indicador até ao presente ainda não utilizado em Portugal. O chumbo é um metal de ocorrência natural, cujos níveis nos diversos ecossistemas resultam, principalmente, das actividades antropogénicas de natureza doméstica e industrial. A sua capacidade poluente é assinalável, representando uma fonte de exposição permanente para o homem, demonstrável pela sua constante presença no organismo apesar de não desempenhar qualquer tipo de função fisiológica. São actualmente inúmeras as suas aplicações, tornando a exposição profissional ao chumbo uma realidade vasta: indústrias de acumuladores eléctricos, de vidros, de plásticos e de munições, construção civil, manutenção e reparação automóvel e de navios, fabrico de tintas, indústrias electrónicas, fundições e actividades de soldadura são, entre outras, situações onde é uma realidade a ter em conta. A penetração dos compostos inorgânicos de chumbo no organismo efectua-se principalmente por via respiratória, não sendo, no entanto, desprezável, a sua penetração por via digestiva. As partículas absorvidas são transportadas pelo sangue principalmente ligadas aos eritrocitos (95%), distribuem-se pelos tecidos moles e depositam-se essencialmente no tecido ósseo, onde representam mais de 90% da carga corporal do total absorvido e tendo aí um elevado tempo de semi-vida (mais de 20 anos). Não é metabolizado no organismo e a sua eliminação efectua-se essencialmente por via renal,sendo igualmente excretado, em menor escala, através das fezes, do suor, da saliva, das faneras e do leite materno. O conhecimento científico evidencia que concentrações sanguíneas de chumbo entre 20 e 50 mg/dL são susceptíveis de determinar efeitos adversos no homem, podendo ser afectados o sistema hematopoiético, o sistema nervoso, o sistema cardiovascular, o sistema reprodutor e o sistema imunitário. Contudo, ainda muito há a clarificar no âmbito da toxicidade do chumbo. Os níveis de exposição a que correspondem as alterações nos diversos órgãos e sistemas continuam a ser motivo de alguma controvérsia. As características carcinogénicas e mutagénicas do chumbo são, ainda, um campo de vasta exigência de investigação. A intoxicação por chumbo e seus sais (Saturnismo) de origem ocupacional é reconhecida em Portugal como doença profissional (grupo 1 - Doenças Provocadas por Agentes Químicos, da Lista das Doenças Profissionais). É uma intoxicação do tipo crónico, fruto da absorção contínua de doses relativamente pequenas durante longo período, evidenciando-se no seu início por sinais e sintomas vagos e difusos de grande inespecificidade, que podem incluir, nomeadamente, perda de apetite, sabor metálico na boca, palidez, mal-estar e fadiga, cefaleias, mialgias e artralgias, irritabilidade, tremores finos, obstipação, cólicas abdominais, insónias, déficit da memória de curto prazo e da capacidade de concentração. Um importante conjunto de indicadores biológicos pode ser utilizado na vigilância periódica da saúde de trabalhadores nestas condições de exposição. Tais indicadores (de dose ou de efeito), encerram diferentes significados e comportam distintas exigências, competindo ao Médico do Trabalho, no âmbito dos programas de prevenção dos efeitos adversos relacionados com a exposição profissional a chumbo, seleccionar a sua utilização e interpretar a sua informação, de modo a avaliar a interacção do tóxico com o organismo numa fase de reversibilidade. O presente estudo envolveu 180 trabalhadores dos quais 110 apresentavam plumbémias (Pb-S) iguais ou superiores a 40 mg/dL. Além da Pb-S, a todos foi doseada a protoporfirina-zinco (PPZ) e efectuado o Hemograma e a cerca de 25% foi determinada a concentração do ácido d-aminolevulínico urinário (ALA-U). Os doseamentos da PPZ efectuados em amostra de sangue capilar através de um hematofluorímetro portátil revelaram-se de total fiabilidade, dando significado a uma técnica de fácil execução e baixo custo. A avaliação do tipo de colheita urinária para doseamento do ALA-U concluiu pela necessidade de recurso a urinas de 24 horas.Os resultados do estudo evidenciaram uma elevada associação entre a PPZ e a Pb-S, com uma maior magnitude e de início mais precoce do que o que registado na associação da Pb-S com o ALA-U. Revelaram, ainda, fracos níveis de associação da hemoglobina (e outros parâmetros hematológicos) com a Pb-S. E demonstraram para um cut-off de 100 mg/ dL de PPZ, taxa de falsos negativos e falsos positivos, para plumbémias a partir de 70 mg/dL, inferiores a 20%. Assim, concluiu-se que, nos protocolos de vigilância de saúde de trabalhadores expostos a chumbo, o doseamento da PPZ por hematofluorímetro, em sangue de colheita capilar, é adequado, fiável e de realização preferencial em relação ao do ALA-U. Concluiu-se, também, que a realização do hemograma apenas se justifica em situações individuais que clinicamente o tornem aconselhável. E que estes protocolos devem incluir a realização da Pb-S e da PPZ, podendo, em situações de controlo rigoroso (ambiental, biológico e clínico), basear-se apenas na determinação da PPZ reservando os outros indicadores para aprofundar a investigação médica nos casos de taxas elevadas desta ou de situações limitantes. ■ Résumée Une stratégie d’évaluation et de prévention des risques d’exposition aux agents chimiques doit toujours tenir en considération que la vigilance du lieu de travail et de la santé des travailleurs sont des aspects complémentaires d’une même réalité – les risques résultant d’une interaction entre l’agent chimique et les travailleurs exposés. Si c’est à la Vigilance Ambiantale de juger le risque, par la caractérisation de l’agent dans le lieu de travail, la Vigilance Biologique, elle, se prononce sur l’interaction entre le toxique et l’organisme, évaluant la réponse à l’agression chimique et l’évolution des réactions d’adaptation ou de rupture face à l’absorption du toxique. Les Indicateurs Biologiques assument ainsi un statut d’instrument privilégié de vigilance de la santé des travailleurs exposés, dans la mesure où ils déterminent la quantité de toxique qui a effectivement été pénétré et absorbé, ou le résultat (effet) déterminé par cette dose. Cette étude-ci cherche à contribuer à la définition d’un cadre méthodologique d’utilisation des Indicateurs Biologiques dans l’évaluation/ gestion de l’exposition professionnelle au plomb inorganique, évaluant spécialement le comportement de la protoporphirine-zinc (PPZ), indicateur pas encore utilisé au Portugal.Le plomb est un métal d’occurrence naturelle dont les niveaux dans les différents écosystèmes en résultent, principalement, des activités anthropogéniques de nature domestique et industrielle. Sa capacité polluante peut être signalée, représentant une source d’exposition permanente pour l’homme, celle-ci démontrable par sa présence continue dans l’organisme, même si elle n’y accomplit aucune fonction physiologique. Actuellement ses applications sont innombrables, faisant de l’exposition professionnelle au plomb une réalité de grande ampleur : industries d’accumulateurs électriques, de verre, de plastique et de munitions, bâtiments, manutention et réparation automobile et navale, fabrication d’encres, industries électroniques, fontes et activités de soudure sont, entre autres, des situations réelles a en tenir compte. La pénétration du plomb inorganique dans l’organisme se fait principalement par voie respiratoire, pouvant se faire également par voie digestive. Les particules absorbées sont transportées par le sang, surtout liées aux érythrocytes (95%), se repartent à travers les tissus mous et se déposent essentiellement dans le tissu osseux, où elles représentent plus de 90% de la charge corporelle de ce qui a été absorbé et ont un temps de demi-vie élevé (plus de 20 ans). Le plomb n’est pas métabolisé dans l’organisme et son élimination se fait essentiellement par voie rénale, pouvant tout de même, à une moindre échelle, être excrété dans les fèces, de la sueur, de la salive, des ongles, des cheveux et du lait maternel. La connaissance scientifique met en évidence que des concentrations sanguines de plomb entre 20 et 50 mg/dL sont susceptibles de déterminer des effets adverses dans l’homme, pouvant les systèmes hématopoïétique, nerveux, cardiovasculaire, reproducteur et immunitaire en être affectés. Cependant, il en reste beaucoup à éclaircir dans le domaine de la toxicité du plomb. Les niveaux d’exposition auxquels correspondent les modifications des divers organes et systèmes, demeurent toujours sujet de quelque controverse. Les caractéristiques carcinogèniques et mutagèniques du plomb restent toujours un champ d’investigation d’une grande exigence. L’intoxication par le plomb et ses sels (Saturnisme) d’origine occupationnelle est reconnue, au Portugal, comme une maladie professionnelle (groupe 1- Maladies Provoquées par des Agents Chimiques, de la Liste des Maladies Professionnelles). C’est une intoxication du tipe chronique, due à l’absorption continue de doses relativement petites pendant une longue période, mise en évidence à travers des signes et des symptômes vagues et diffus sans grande spécificité, lesquels peuvent inclure, particulièrement, le manque d’appétit, goût métallique dans la bouche, pâleur, malaise et fatigue, céphalées, myalgies et arthralgies, irritabilité, tremblements fins, constipation, coliques abdominales, insomnies, déficit de la mémoire à court terme et de la capacité de concentration.Un ensemble important d’indicateurs biologiques peut être employé dans la vigilance périodique de la santé des travailleurs dans ces conditions d’exposition. Ces indicateurs (de dose ou d’effet) renferment différentes significations et comportent diverses exigences, devant le Médecin de Travail, dans le domaine des programmes de prévention des effets adverses qui sont en relation avec l’exposition professionnelle au plomb, sélectionner son utilisation et interpréter son information de façon à évaluer l’interaction de l’élément toxique avec l’organisme à un stade de réversibilité. L’étude ci-présent engloba 180 travailleurs desquels 110 présentaient des plombémies (Pb-S) égales ou supérieures à 40 mg/dL. À part la Pb-S, la protoporphyrine-zinc (PPZ) leur a été prise en dosage et un Hémogramme fut effectué et fut déterminé l’acide d- aminolévulinique urinaire (ALA-U) sur environ 25% des travailleurs. Le dosage de la PPZ efectué en échantillon de sang capillaire par un fluorimètre portable, s’est accomplit d’une fiabilité total, donnant du sgnificat à une téchnique de facile execution et bas prix. L’évaluation de la prise urinaire par dosage du ALA-U conclut au besoin d’un recours aux urines de 24 heures Les résultats de l’étude ont mis en évidence une association élevée entre la PPZ et la Pb- S, avec une intensité majeure et de début plus précoce par rapport à celui qui fut registré lors de l’association de la Pb-S avec la ALA-U. Ces résultats ont également montré de faibles niveaux d’association entre l’hémoglobine (et autres paramètres hématologiques) et la Pb-S. Ils ont démontré aussi, une valeur de cut-off de 100 mg/dL de PPZ, des taux de faux négatifs et faux positifs, pour des plombémies de 70 mg/dL, inférieurs à 20%. On peut donc conclure que dans les protocoles de vigilance de la santé des travailleurs exposés au plomb, le dosage de la PPZ par fluorimetrie dans le sang capillaire est adéquat, fiable et de réalisation préférentielle par rapport à celui du ALA-U. On peut également conclure que la réalisation de l’hémogramme ne se justifie que dans les cas individuels où, cliniquement, celui-ci est conseillé. De plus, ces protocoles doivent inclure la réalisation de la Pb-S et de la PPZ, pouvant, en cas de contrôle rigoureux (ambiantal, biologique et clinique), s’appuyer que dans la détermination de la PPZ réservant les autres indicateurs pour approfondir l’investigation médicale dans les cas où les taux de celle-ci sont élevés ou dans les cas de situations limitantes. ■ Summary Any strategy to evaluate and prevent the risks of chemical agents exposure must always regard the work environment and workers health as complementary aspects of one reality - the resulting risks from the interaction between the chemical agent and the exposed workers. It is the responsibility of Environmental Monitoring to evaluate the risks of exposure by the characterization of the chemical agent in the work environment. Biological Monitoring, on the other hand, pronounces itself over the toxin and body interaction, evaluating human response to the chemical aggression and the body adaptations to the toxic absorption. Biological Exposure Indices (BEI) assume, therefore, a privileged status among exposed workers' health monitoring instruments, as they measure the actual penetrated and absorbed toxic quantity and the effect it produces. This research study aims to contribute to the definition of a methodological strategy on the utilization of BEI’s in evaluating inorganic lead's occupational exposure, more specifically appreciating the zinc protoporphyrin (ZPP) variation, an index that has never been taken under consideration in Portugal until now. Lead is a natural metal whose ecosystem’s levels are mainly due to domestic and industrial anthropogenic activities. Its pollutant capacity is notable, representing a permanent exposure risk shown by its constant presence in the human body, although it has no physiologic function. Nowadays, lead's applications are countless, turning its professional exposure a huge reality: storage batteries industries, glass industries, plasterers and munitions industries, building construction, ships and motor car maintenance and repairing, ink manufacture, electronics industries, foundries and other soldering activities are, among so many other, realities to attend to. Respiration is the main cause of human body's inorganic lead absorption, although digestive pathway must not to be ignored. The absorbed particles are transported by blood, essentially bounded to erythrocytes (95%). It is distributed by soft tissues and settled mainly on bone tissues, where it represents approximately 90% of the total body charge and has a high half-life time (more than 20 years). It is not metabolized by the organism, its elimination being effectuated by renal activity and, in smaller scale, through lees, sweat, saliva, nails, hair and maternal milk.Scientific knowledge shows that concentrations of lead in blood between 20 e 50 mg/dL are susceptible to determine adverse effects in man and able to affect the hematopoietic system, the nervous system, the cardiovascular system, the reproductive system and the immunological system. Nevertheless, there's still much to be learned and clarified about lead's toxicity. The correlation between exposure levels and human's systems and organs alteration levels continues to be a centre of controversies. Still, lead's carcinogenic and mutagenic characteristics continue to be a high demanding research field. Intoxication by lead and its compounds (saturnism), from occupational origin, is recognized in Portugal as an occupational disease, included in Group 1 - Chemical Agents Caused Diseases, on the Occupational Diseases List. It is a chronic intoxication caused by a continuous absorption of small doses, throughout a long period of time. Its signs and symptoms are diffuse and imprecise, of great unspecificity, such as loss of appetite, metallic flavor in the mouth, paleness, ailment and fatigue, headaches, myalgia and arthralgia, irritability, thin tremors, constipation, abdominal pain, insomnias, short memory loses and inability to concentrate. A considered number of BEI’s can be used in Periodic Health Monitoring of workers in such exposure conditions. Such BEI (dose indices or effect indices) provide different meanings and imply different procedures, being Occupational Doctors responsibility, in the context of lead related adverse effects preventive programmes, to select and interpret its information, in order to evaluate the interaction between toxic and organism in a reversible phase of the toxic action. The present research study involved 180 workers, 110 of which presented blood lead levels (PbB) above or equal to 40 mg/dL. Besides PbB, all workers has been evaluated for zinc protoporphyrin levels (PPZ) and submitted to a haemogram. About 25% of the workers were selected for d-aminolevulinic urinary acid (ALA-U) determination. The evaluation of PPZ, by a portable hematofluorometer using capillary blood samples, turned out to be an easy procedure with low costs and total warrantability. As in regard for ALA- U procedure, it was concluded the necessity of 24 hours urine samples. This research results underlined a strong connection between ZPP and PbB, which was found to to be stringer and to begin earlier than it was registered for PbB and ALA-U association. The same study also revealed a low association level between PbB and hemoglobin or other hematological indices. It was also verified less than 20% of false negatives and false positives cases when admitted a ZPP 100 mg/dL cut off value for PbB³ 70 mg/dL. As in result it was concluded that in Health Monit

Age-period-cohort effects in the incidence of hip fractures: political and economic events are coincident with changes in risk

Introduction: Healthcare improvements have allowed prevention but have also increased life expectancy, resulting in more people being at risk. Our aim was to analyse the separate effects of age, period and cohort on incidence rates by sex in Portugal, 2000–2008. Methods: From the National Hospital Discharge Register, we selected admissions (aged ≥49 years) with hip fractures (ICD9-CM, codes 820.x) caused by low/moderate trauma (falls from standing height or less), readmissions and bone cancer cases. We calculated person-years at risk using population data from Statistics Portugal. To identify period and cohort effects for all ages, we used an age–period–cohort model (1-year intervals) followed by generalised additive models with a negative binomial distribution of the observed incidence rates of hip fractures. Results: There were 77,083 hospital admissions (77.4 % women). Incidence rates increased exponentially with age for both sexes (age effect). Incidence rates fell after 2004 for women and were random for men (period effect). There was a general cohort effect similar in both sexes; risk of hip fracture altered from an increasing trend for those born before 1930 to a decreasing trend following that year. Risk alterations (not statistically significant) coincident with major political and economic change in the history of Portugal were observed around birth cohorts 1920 (stable–increasing), 1940 (decreasing–increasing) and 1950 (increasing–decreasing only among women). Conclusions: Hip fracture risk was higher for those born during major economically/politically unstable periods. Although bone quality reflects lifetime exposure, conditions at birth may determine future risk for hip fractures.

Thermal performance of cool facades: evaluation by Infrared Thermography

High reflective paints (cool paints) are used on flat roofs to reduce heat gains from the incidence of solar radiation and thus improve the thermal comfort and energy efficiency of buildings, especially in summer periods. Given the application potential of these paints on vertical surfaces, a research study has been developed to evaluate the thermal performance of reflective paints on walls under real exposure conditions. Accordingly, different reflective paints have been applied as the final coating of an ETICS type solution, on the facades of a full scale experimental cell built at LNEC campus. For being applied in an ETICS system a paint has to fulfill several requirements, whether aesthetic or functional (such as the adhesion between the coating layers or the durability of the insulation), essential for its efficient performance. Since this construction coating system is subject to a prolonged sun exposure, various problems may arise, such as paint degradation or deterioration of the thermal insulation properties, particularly when dark colors are applied. To evaluate the thermal performance of the chosen paints, the method of non-destructive analysis by Infrared Thermography was used. Thermography allows knowing the temperature distribution of facades by measuring the radiation emitted by their surfaces. To complement the thermographic diagnosis, thermocouples were placed between the insulation and the paint system of the experimental cell. Additional laboratory tests allowed the characterization of the optical properties (reflectance and emittance) of the different reflective paints used in this study. The comparative analysis of the thermal performance of reflective and conventional paints revealed that the reflective paint allows a reduction of the facade surface temperature, reducing the risk of loss of insulating properties of the ETICS system and thus ensuring its longevity and functionality. The color of the paint used affects, naturally, the reflective ability of the surface and may have an important role in energy balance of the building. This paper also showed the potential of infrared thermography in the evaluation of the thermal performance of reflective paints.

Impact of biological and environmental variabilities on biological monitoring: an approach using toxicokinetic models

Biological monitoring of occupational exposure is characterized by important variability, due both to variability in the environment and to biological differences between workers. A quantitative description and understanding of this variability is important for a dependable application of biological monitoring. This work describes this variability,using a toxicokinetic model, for a large range of chemicals for which reference biological reference values exist. A toxicokinetic compartmental model describing both the parent compound and its metabolites was used. For each chemical, compartments were given physiological meaning. Models were elaborated based on physiological, physicochemical, and biochemical data when available, and on half-lives and central compartment concentrations when not available. Fourteen chemicals were studied (arsenic, cadmium, carbon monoxide, chromium, cobalt, ethylbenzene, ethyleneglycol monomethylether, fluorides, lead, mercury, methyl isobutyl ketone, penthachlorophenol, phenol, and toluene), representing 20 biological indicators. Occupational exposures were simulated using Monte Carlo techniques with realistic distributions of both individual physiological parameters and exposure conditions. Resulting biological indicator levels were then analyzed to identify the contribution of environmental and biological variability to total variability. Comparison of predicted biological indicator levels with biological exposure limits showed a high correlation with the model for 19 out of 20 indicators. Variability associated with changes in exposure levels (GSD of 1.5 and 2.0) is shown to be mainly influenced by the kinetics of the biological indicator. Thus, with regard to variability, we can conclude that, for the 14 chemicals modeled, biological monitoring would be preferable to air monitoring. For short half-lives (less than 7 hr), this is very similar to the environmental variability. However, for longer half-lives, estimated variability decreased. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: tables detailing the CBTK models for all 14 chemicals and the symbol nomenclature that was used.] [Authors]

Immune responses to airborne fungi and non-invasive airway diseases.

Inhalation of fungal particles is a ubiquitous way of exposure to microorganisms during human life; however, this exposure may promote or exacerbate respiratory diseases only in particular exposure conditions and human genetic background. Depending on the fungal species and form, fungal particles can induce symptoms in the lung by acting as irritants, aeroallergens or pathogens causing infection. Some thermophilic species can even act in all these three ways (e.g. Aspergillus, Penicillium), mesophilic species being only involved in allergic and/or non-allergic airway diseases (e.g. Cladosporium, Alternaria, Fusarium). The goal of the present review is to present the current knowledge on the interaction between airborne fungal particles and the host immune system, to illustrate the differences of immune sensing of different fungal species and to emphasise the importance of conducting research on non-conventional mesophilic fungal species. Indeed, the diversity of fungal species we inhale and the complexity of their composition have a direct impact on fungal particle recognition and immune system decision to tolerate or respond to those particles, eventually leading to collateral damages promoting airway pathologies.

Large gypsum nodules in the Paleogene and Neogene evaporites of Spain: distribution and palaeogeographic significance

Sabkha and deep burial set tings are the most com mon sites where diagenetic anhydrite forms. In a sabkha setting, displacive facies (iso lated nodules, bed ded nodules, enterolithic levels) of early diagenetic or primary anhydrite are generated (Shearman, 1966; Hardie, 1967). These anhydrite facies are commonly foundat the top of shoal ing cycles representing the evolution from subaqueous depositional conditions at the base (carbonates, lutites) to exposure conditions at the top where in ter stitially-grown gypsum/anhydrite de velops ( sabkha cy cles). In a deep burial setting, gypsum transforms to tally to anhydrite with in creas ing temperature and lithostatic pressure (Murray, 1964). Al though this mineral transformation usually preserves the depositional gypsum facies, a significant textural change is in volved in other cases, resulting in replacive anhydrite with a nodular-mosaic or"chicken-wire" fabric (Warren, 2006). In the two settings, how ever, the size of the individual anhydrite nodules is relatively small, rarely reaching some tens of centimetres across. More over, bedding is preserved or little disturbed, al though minor de formation is caused by the displacive sabkha nodules.

Profile of cortisol, glycaemia, and blood parameters of American Bullfrog tadpoles Lithobates catesbeianus exposed to density and hypoxia stressors

The aim of this study was to evaluate alterations to the physiological profile (cortisol, glycaemia, and blood parameters) of Lithobates catesbeianus caused by the stressors density and hypoxia. The organisms were in the prometamorphosis stage and exposed to different tadpole densities: 1 tadpole/L (T1), 5 tadpoles/L (T2), and 10 tadpoles/L (T3) for 12 days. The blood was collected through the rupture of the caudal blood vessel and collected under normoxia (immediate collection) and hypoxia (after 15 minutes of air exposure) conditions. Cortisol levels rose on the fourth and eighth days of treatment and returned to basal levels by the end of the experiment. The stressor mechanisms tested did not affect glycaemia. White blood cells (total number of lymphocytes, neutrophils, and eosinophils) showed a significant difference at the twelfth day of the experiment when compared with the start of the experiment. We concluded that, under controlled conditions, a density of up to 10 tadpoles/L and air exposure for 15 minutes did not cause harmful physiological alterations during the experimental period. The answer to these stressors maybe was in another hormonal level (corticosterone).