A toxicidade das nanopartículas de prata e nitrato de prata em larvas de Nassarius reticulatus

Mestrado em Toxicologia e EcotoxicologiaProduction and utilization of silver nanoparticles (AgNPs) for various applications is growing rapidly, mainly due to their antibacterial activity. Their inclusion in many consumer products led to an increased release of AgNPs in the environment, especially in aquatic ecosystems. AgNPs reach both freshwater and marine environments from the effluents of the wastewater treatment plants, presenting differentiated behavior in these two environments potentially influencing its toxicity. The study of AgNPs toxicity to marine organisms is extremely important to the assessment of the potential risk of AgNPs in the environment. The toxicity of AgNPs on the living organisms is dependent on various environmental conditions. Regarding the toxicity of AgNPs in the marine environment, there is a lack of information on the toxic effects at different salinities. This study upsurges to fill this gap, being the first report on the effects of AgNPs on marine gastropods, using Nassarius reticulatus as a case study. N. reticulatus adults were collected from a reference population in Ria de Aveiro (NW Portugal, 40° 38' 33.24"N | 8° 44' 06.69’’W). Specimens were transported to the laboratory in local seawater and kept in aquaria to spawn. Egg capsules were maintained until veliger larva were noticed, which enclosure was induced by cesarean. These recently hatched larvae were then exposed to nominal concentrations of AgNPs and Ag+ (0.1, 1, 10, 100 μg Ag/L) for up to 96 h, either in the presence or absence of food. Larval mortality and swimming behavior –namely the velum beating arrest–were determined for each treatment. The median lethal concentration (LC50) of AgNPs was higher to that of ionic Ag (AgNO3). Results also revealed that the negative impact of AgNPs on N. reticulatus veligers swimming ability is higher when compared with the effect of ionic Ag (EC50-96 h 1.044 μg Ag/L). However, although the velum arrests have significantly decreased under Ag+ exposure, AgNPs did not show any effects. Additionally, the presence of the food proved to be an effective factor that can cause a significant drop in the mortality of the N. reticulatus larvae exposed to AgNPs.A produção e utilização de nanopartículas de prata (AgNPs) em diversas aplicações têm crescido rapidamente, principalmente devido à sua atividade antibacteriana. A inclusão de AgNPs em muitos produtos de consumo conduziu a um aumento da sua libertação no meio ambiente, especialmente nos ecossistemas aquáticos. As AgNPs atingem tanto o ambiente marinho como o de água doce a partir da descarga de efluentes de estações de tratamento de águas residuais, apresentando comportamento diferenciado nestes dois meios, potencialmente influenciando a sua toxicidade. O estudo da toxicidade das AgNPs em organismos marinhos é extremamente importante na avaliação do potencial risco da presença de AgNPs no ambiente. A toxicidade de AgNPs emorganismos vivos é dependente de várias condições ambientais. No que se refere à toxicidade das AgNPs em ambiente marinho, verifica-se uma lacuna de informação relativamente aos efeitos tóxicos a diferentes salinidades. Este trabalho surge para preencher esta lacuna, sendo o primeiro relato do efeito de AgNPs em larvas de gastrópodes marinhos, usando Nassarius reticulatus como caso de estudo. Foram colhidos adultos de N. reticulatus de uma população de referência da Ria de Aveiro (NW Portugal, 40° 38' 33.24"N | 8° 44' 06.69’’W). Os espécimes foram transportados para o laboratório em água do local e aí mantidos em aquário até à postura de cápsulas ovígeras. As cápsulas foram mantidas até à observação de larvas velígeras no seu interior, cuja eclosão foi induzida por cesariana. Estas larvas recém-eclodidas foram então expostas a concentrações nominais de AgNPs e Ag+ (0,1, 1, 10, 100 ug de Ag / L), durante 96 h, na presença ou ausência de alimento. A mortalidade larvar e o comportamento de natação, nomeadamente a inibição do batimento do velum, foram determinados para cada um dos tratamentos. A concentração letal média (CL50) das AgNPs revelou-se superior à da Ag iónica (AgNO3). Os resultados também revelaram que o impacto negativo das AgNPs na natação das velígeras de N. reticulatus é superior (EC50-96 h 0.044 μg Ag/L) quando comparado com o efeito da Ag iónica (EC50-96 h 1.044 μg Ag/L). Contudo, embora a inibição da movimentação do velum das larvas ter diminuido significativamente na presença de Ag+, as AgNPs não mostraram quaisquer efeitos na inibição do batimento do velum. Adicionalmente, a presença de alimento revelou ser um fator importante, podendo causar uma redução significativa na mortalidade das larvas de N. reticulatus expostas a AgNPs

Toxicokinetics of silver nanoparticles in the mealworm Tenebrio molitor exposed via soil or food

Silver nanoparticles (AgNPs) may reach the soil compartment via sewage sludge or nanoagrochemical applications. Understanding how NPs interact with biological systems is crucial for an accurate hazard assessment. Therefore, this study aimed at determining the Ag toxicokinetics in the mealworm Tenebrio molitor, exposed via Lufa 2.2 soil or via food to different Ag forms (uncoated 50 nm AgNPs, paraffin coated 3–8 nm and PVP-stabilised 60 nm, Ag2S NPs 20 nm, and ionic Ag). Mealworms were exposed for 21 days followed by a 21-day elimination phase (clean soil/food). A one-compartment kinetics model with inert fraction (simulating a storage compartment, where detoxified forms are located) was used to describe Ag accumulation. Fully understanding the uptake route in mealworms is difficult. For that reason several approaches were used, showing that food, soil and pore water all are valid uptake routes, but with different importance. Silver taken up from soil pore water or from soil showed to be related to Ag dissolution in soil pore water. In general, the uptake and elimination rate constants were similar for 3–8 nm and 60 nm AgNPs and for AgNO3, but significantly different for the uncoated 50 nm AgNPs. Upon food exposure, uptake rate constants were similar for 50 nm AgNPs and AgNO3, while those for 60 nm and 3–8 nm AgNPs and for Ag2S NPs also grouped together. NP exposure in soil appeared more difficult to characterize, with different patterns obtained for the different NPs. But it was evident that upon soil or food exposure, particle characteristics highly affected Ag bioavailability and bioaccumulation. Although Ag2S NPs were taken up, their elimination was faster than for other Ag forms, showing the lowest inert fraction. The significantly different elimination rate constants suggest that the mechanism of elimination may not be the same for different AgNPs either

Toxicocinética de nanopartículas de prata em organismos do solo

Nanomaterials are already used in many products and still, the global nanotechnology market is growing. A major route of emission of consumed silver nanoparticles (AgNPs) to soil is through sewage sludge applied as fertilizer. Understanding the possible bioaccumulation of nanoparticles (NPs) in soil organisms is urgently needed as part of their risk assessment. Since NPs are thermodynamically unstable, not likely achieving equilibrium, toxicokinetic studies may indicate their bioavailability and potential for bioaccumulation. Considering the expected transformation of all consumed AgNPs to silver sulfide (Ag₂S), and the lack of enough data regarding Ag₂S bioavailability to terrestrial organisms, this thesis aimed to investigate the toxicokinetics in terrestrial organisms of both pristine (with different coating and size) and sulfidized silver nanoparticles. Ag₂S NPs are simulating aged AgNPs passing through wastewater treatment plants (WWTPs). Different test species were used to assess Ag toxicokinetics under a relevant environmental exposure scenario. This thesis is divided into four studies. The first two studies focused on determining Ag uptake in two invertebrates, mealworms Tenebrio molitor (via Lufa 2.2 soil or food) and enchytraeids Enchytraeus crypticus (via three different soils). Next, the uptake kinetics of Ag in T. molitor and isopods Porcellio scaber was investigated in indoor terrestrial mesocosms as a more relevant environmental condition. Finally, the toxicokinetics and distribution of Ag was studied in the plant Brassica rapa. Exposure of T. molitor and E. crypticus displayed different uptake kinetics for different Ag forms, indicating the effect of AgNP form, characteristics and mainly dissolution on its bioavailability. In both invertebrate species, Ag from Ag₂S NPs could be taken up, but it was eliminated faster than Ag from other Ag forms which may be related to the stability of Ag₂S NPs compared to pristine AgNPs. Significant effects of soil properties on the bioavailability and uptake of Ag nanoparticles were observed in E. crypticus exposed to Ag₂S NPs and AgNO₃ through different soils (Dorset, Woburn, and Lufa 2.2), especially in the Dorset soil, which high sand content and low pH caused clustering behavior of the animals. For checking if the results obtained in standard single-species test could predict Ag uptake under more complex but realistic conditions, the uptake kinetics of Ag₂S NPs and AgNO₃ in T. molitor and P. scaber were estimated in indoor mesocosm with multiple species and with rain application. The single-species tests could not predict Ag uptake in mealworms and isopods in exposure systems having higher levels of biological complexity. To determine the uptake kinetics and distribution of Ag during the growth of the plant up to the complete life cycle, seeds of B. rapa were planted in soil spiked with different Ag forms. The accumulation of Ag in B. rapa differed during the plant life cycle and a two-stage two-compartment model was introduced to describe its uptake kinetics. The concentration of Ag taken up in roots 7 days after germination was about 14 and 10 times lower for Ag₂S NPs than for the pristine AgNPs and AgNO₃ exposures, respectively, but the Ag from the Ag₂S NPs was transferred to the shoots faster than for the other Ag forms. Distribution of Ag in plants exposed for up to 42 days after germination to different Ag forms differed: about 50% of the Ag taken up was present in the shoots for Ag₂S NPs and AgNO₃, but only 20% for the pristine 3-8 or 50 nm AgNPs. Although sulfidation processes in WWTPs significantly decreased its bioavailability, investigating different relevant environmental conditions is required as some conditions may lead to unexpected changes in the bioavailability of sulfidized Ag form NPs.Os nanomateriais são atualmente utilizados em muitos produtos, estando o mercado global associado à nanotecnologia a crescer. Uma das principais vias de emissão de nanopartículas de prata consumidas (AgNPs) para o solo é através de lamas ou biosólidos aplicados como fertilizantes. É, assim, urgente compreender a possível bioacumulação de nanopartículas (NPs) em organismos do solo como parte de sua avaliação de risco. Como as NPs são termodinamicamente instáveis, provavelmente não atingindo um equilíbrio, os estudos toxicocinéticos podem fornecer informação sobre a sua biodisponibilidade e potencial de bioacumulação. Considerando a esperada transformação de todas as AgNPs consumidas em sulfeto de prata (Ag₂S), e a falta de dados suficientes sobre a biodisponibilidade de Ag₂S para organismos terrestres, esta tese teve como objetivo investigar a toxicocinética de AgNPs pristinas (na forma sintetizada, com diferentes revestimentos e tamanhos), assim como de Ag₂S NP em organismos de solo. Estas Ag₂S NPs simulam, então, o tipo de NPs de prata esperadas após decorrer o processo de tratamento de águas residuais. Para avaliar a toxicocinética de Ag num cenário de exposição ambiental relevante, foram usadas várias espécies-teste. Esta tese está dividida em quatro estudos, em que nos dois primeiros se determina a absorção de Ag em dois invertebrados, o Tenebrio molitor (via solo Lufa 2.2 ou alimento) e o enquitreídeo Enchytraeus crypticus (através de três solos diferentes). Em seguida, a cinética de absorção de Ag em T. molitor e no isópode Porcellio scaber foi investigada em mesocosmos terrestres, em laboratório, como uma condição ambiental mais relevante. Por fim, estudou-se a toxicocinética e distribuição de Ag na planta Brassica rapa. A exposição de T. molitor e E. crypticus apresentou diferentes cinéticas de absorção para diferentes formas de Ag, indicando o efeito da forma, características e principalmente dissolução da AgNP na sua biodisponibilidade. Em ambas as espécies de invertebrados, foi observada a aborção da Ag das Ag₂S NPs, mas sendo elimninada mais rapidamente do que a Ag das outras formas de Ag, o que pode estar relacionado com a estabilidade das Ag₂S NPs em comparação com as AgNPs pristinas. Foram igualmente observados efeitos significativos das propriedades do solo sobre a biodisponibilidade e absorção de nanopartículas de Ag em E. crypticus expostos a Ag₂S NPs e AgNO₃, utilizando solos com características diferentes (Dorset, Woburn e Lufa 2.2); especialmente no solo Dorset, que possui um alto teor de areia e baixo pH, observou-se um comportamento de agrupamento dos animais. Para verificar se os resultados obtidos nos testes padronizados com uma única espécie poderiam prever a absorção de Ag sob condições mais complexas, e realistas, a cinética de absorção de Ag₂S NPs e AgNO₃ em T. molitor e P. scaber foi estimada em mesocosmos de laboratório, com a utilização de várias espécies e com a adição de chuva artificial. Os testes de espécie única não preveem de forma adequada a absorção de Ag em larvas de farinha e isópodes expostos em sistemas de exposição com níveis mais altos de complexidade biológica. Para determinar a cinética de absorção e distribuição de Ag durante o crescimento da planta, durante o ciclo de vida completo, sementes de B. rapa foram plantadas em solo contaminado com diferentes formas de Ag. A acumulação de Ag em B. rapa foi diferente ao longo do ciclo de vida da planta e um modelo de dois estágios de dois compartimentos foi utilizado para descrever a cinética de absorção da Ag. A concentração de Ag absorvida nas raízes 7 dias após a germinação foi cerca de 14 e 10 vezes menor para Ag₂S NPs do que para as exposições de AgNPs e AgNO₃, respectivamente, mas a Ag das Ag₂S NPs foi transferida para a parte aérea mais rapidamente do que nas outras formas de Ag. A distribuição de Ag nas plantas expostas por 42 dias (após a germinação) a diferentes formas de Ag diferiu: cerca de 50% da Ag absorvida estava presente na parte aérea para Ag₂S NPs e AgNO₃, mas apenas 20% para as 3-8 nm e 50 nm AgNP (pristinas). Embora os processos de sulfetação em Estações de Tratamento de Águas Residuais tenham diminuído significativamente a biodisponibilidade da Ag, é necessário investigar diferentes condições ambientais relevantes, pois algumas condições podem levar a alterações inesperadas na biodisponibilidade de AgNPs na sua forma sulfetada.Programa Doutoral em Biologi

The Effects of Exports Sophistication and Economic Freedom on Economic Growth in Select Oil-Exporting Countries

Export sophistication, which means producing and exporting goods that are more sophisticated and have more value-added, along with economic freedom can influence economic growth in different countries through technological improvement, increasing expertise and encouraging innovation. This study examines the effects of export sophistication and economic freedom as factors that influence economic growth in a selection of oil-exporting countries. To meet this end, the export sophistication index is calculated based on Hausman et al. (2007) for period 1998 to 2017. The results indicate that, due to high share of oil and gas in the export basket, the sophistication of exported goods in the select countries is relatively low. However, this index has a positive significant effect on economic growth of select countries with a coefficient of 0.41. The economic freedom index in select countries is close to the global averages and its effect on economic growth is significant and positive with a coefficient of 0.06. Other control variables such as human capital, financial development and gross capital formation are also found statistically significant. Our findings confirm the need for planning to increase sophistication of exports. To achieve this end, apart from producing and exporting goods that are more sophisticated, the development of oil and gas downstream industries, which are capable of producing complex and high value-added goods, should be on the agenda

Investigation of curcumin effects on liver tissue in adult male rats treated with cyclophosphamide

 Background & Objective: Cyclophosphamide is an antineoplastic drug that has many clinical uses in cancer treatment, but it has toxic effects due to creation of free radicals. In this study, the effects of curcumin" as an antioxidant drug” on liver tissue was investigated. Materials & methods: 50 wistar adult male rats were selected randomly and were divided in to five groups including control, sham (receiving normal saline and olive oil), cyclophosphamide (5 mg/kg intraperitoneal), cyclophosphamide (5 mg/kg) + curcumin (50 mg/kg), and curcumin (50 mg/kg by gavage). This study continued for 30 days. The liver histopathological changes were investigated after the last administration. Results: Severe apoptosis, hepatocytes necrosis, congestion, focal inflammation, and endotheliosis were revealed in cyclophosphamide receiving group. However, focal inflammation and hepatocyte necrosis were decreased considerably in cyclophosphamide + curcumin group compared to cyclophosphamide group. Congestion and endotheliosis were very small. None of the above mentioned complications was observed in curcumin receiving group. Conclusion: The results of this study show the concurrent consumption of cyclophosphamide and curcumin can reduce the cyclophosphamide free radicals effects on liver tissue.   &nbsp

The effect of sulfidation and soil type on the uptake of silver nanoparticles in annelid Enchytraeus crypticus

Hazard assessment of silver nanoparticles is crucial as their presence in agricultural land is increasing through sewage sludge application. This study compared the uptake and elimination kinetics in the annelid Enchytraeus crypticus of AgNPs with different core sizes and coatings in Lufa 2.2 soil, and of Ag2S NPs (simulating aged AgNPs) in three different soils. For both experiments, AgNO3 was used as ionic control. E. crypticus was exposed to soil spiked at 10 μg Ag g−1 dry soil for 14 days and then transferred to clean soil for a 14-day elimination phase. The uptake rate constants were similar for 3–8 nm and 60 nm AgNPs and AgNO3, but significantly different between 3 and 8 nm and 50 nm AgNPs. The uptake kinetics of Ag from Ag2S NPs did not significantly differ compared to pristine AgNPs. Therefore, Ag bioavailability was influenced by AgNP form and characteristics. Uptake and elimination rate constants of both Ag forms (AgNO3 and Ag2S NPs) significantly differed between different test soils (Lufa 2.2, Dorset, and Woburn). For AgNO3, significantly higher uptake and elimination rate constants were found in the Dorset soil compared to the other soils, while for Ag2S NPs this soil showed the lowest uptake and elimination rate constants. Therefore, not only the form and characteristics but also soil properties affect the bioavailability and uptake of Ag nanoparticles

Computational Engineering Modeling for Runner Athletes

The literature indicates that relatively little research is available to describe the relationship between functional running tasks and characteristics of individuals who perform these tasks. As a main purpose, the present work is to define the computational modeling for anthropometric characteristics of athletes. Thus the dynamic model presented by this 100-meter running test can play an important role in talent and coaching. The research question was formed by classification and comparison of statures of sportswomen with other anthropometric classes. On the other hand, the present work compares the anthropometric data for runner velocity (running time) against runner weight. The method of research is regression statistical analysis method. In this work, the regression method is based on the univariable ANOVA variance with repeated measures and t-test for independent samples. Data analysis was performed by using the software SPSS13. The results of the 100-meter running test of sportswomen showed good correlation between the parameters. As a dynamic modeling selection, the logarithmic function showed suitable correlation on scatter diagram. Consequently, the results of this work will help to reduce the risk of sportswomen activities. Therefore it can be recommended for medical professionals and athletic talent

REVIEW ON RECENT ADVANCES IN ENVIRONMENTAL REMEDIATION AND RELATED TOXICITY OF ENGINEERED NANOPARTICLES

Production and utilization of engineered nanoparticles (ENPs), which are smart materials with ability of sensing and destroying chemical contaminants, is growing rapidly. However, these materials seem to have some ecological and health adverse effects. Hence, the main goal of this review study is to give a brief description about the recent developments of the commercial available engineered nano particles in the environmental remediation and also to note the current state of findings about the toxic effects of such advanced materials. The key references revealed the potential in vitro and/or in vivo toxic effects of some ENPs which are commonly used in environmental remediation. However, with respect to highly potential physicochemical and biochemical properties of ENPs, the studies which have been carried out till now are not ample to obtain satisfactory exposure data for both human beings and the environment. Therefore, more surveys should be done in this field to fill the gap of high quality data and to develop new engineered nanoparticles with minimum toxicity

Glucose-6-Phosphate Dehydrogenase Deficiency and Neonatal Hyperbilirubinemia

Background: Jaundice is affecting over 60-80 percent of neonates in the first week of life. Glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is an important cause of pathologic hyperbilirubinemia, can lead to hemolytic anemia, jaundice and kernicterus. The present study was performed to determine the prevalence of G6PD deficiency among icteric neonates in Shirvan, Iran. Methods: This descriptive, analytical study was performed by evaluating the medical records of neonates with jaundice, admitted to the neonatal ward of Imam Khomeini Hospital of Shirvan in 2012-2013. All neonates, who were evaluated in terms of G6PD, were included in this study. Data including the clinical signs and symptoms, laboratory test results and maternal history during pregnancy were recorded in the questionnaires. The patients were divided into two groups: with and without G6PD deficiency. The recorded data were compared between the two groups, using t-test and Chi-square test. P-value less than 0.05 was considered statistically significant. Results: Among 452 admitted neonates, 16 (3.5%) presented with G6PD deficiency. There was no significant difference between the two groups in terms of birth weight, weight on admission, Coombs’ test results, hematocrit level, length of hospital stay and total bilirubin level. However, there was a significant difference between the two groups regarding reticulocyte count. Conclusion: Based on the findings, establishment of an early G6PD screening program, which can prevent further complications in neonates, seems essential, particularly in countries such as Iran where G6PD deficiency is highly prevalent

Wastewater treatment and reclamation: a review of pulp and paper industry practices and opportunities

The pulp and paper (P&P) industry worldwide has achieved substantial progress in treating both process water and wastewater, thus limiting the discharge of pollutants to receiving waters. This review covers a variety of wastewater treatment methods, which provide P&P companies with cost-effective ways to limit the release of biological or chemical oxygen demand, toxicity, solids, color, and other indicators of pollutant load. Conventional wastewater treatment systems, often comprising primary clarification followed by activated sludge processes, have been widely implemented in the P&P industry. Higher levels of pollutant removal can be achieved by supplementary treatments, which can include anaerobic biological stages, advanced oxidation processes, bioreactors, and membrane filtration technologies. Improvements in the performance of wastewater treatment operations often can be achieved by effective measurement technologies and by strategic addition of agents including coagulants, flocculants, filter aids, and optimized fungal or bacterial cultures. In addition, P&P mills can implement upstream process changes, including dissolved-air-flotation (DAF) systems, filtration save-alls, and kidney-like operations to purify process waters, thus reducing the load of pollutants and the volume of effluent being discharged to end-of-pipe wastewater treatment plants