Recuperação de terras raras de águas naturais usando nanomateriais à base de carbono

The society has never been so much dependent on electronic and electric devices as it is today. As a result, e-waste has become a worldwide problem not only due to environmental changes that have emerge from the incorrect treatment and storage of e-waste but also because the amount of e-waste is increasing each year. Another problem inherent to electrical and electronic devices is their dependence on rare earth elements. Currently, they are considered as the “vitamins” of modern industry due to their vital role on the development of new cutting-edge technologies due to their distinctive chemical and physical properties. However, the high demand and the limited resources of rare earth elements, combined with the environmental problems associated with their exploration by mining activities, enforce the development of new ways to recover these elements from e-waste and wastewaters. Therefore, the development of low cost techniques and materials for recovery these valuable elements from e-waste is important to face and resolve both issues. In this way, the main objective of this work was to develop an efficient carbonbased composite towards the recovery of rare earths. Most of the sorption studies reported in the literature were performed with ultrapure waters spiked with tens to hundreds mg/L of single rare earth elements; so the objective is to study the recovery from waters of different matrices and using lower element concentrations. The materials synthesized in this work were magnetic exfoliated graphite functionalized with humic acids (MEG-HA), graphene oxide functionalized with ca. 25% of polyethylenimine (GO-PEI) and graphene oxide functionalized with chitosan (GO-CH), and they were evaluated for the REEs recovery capacity, using different amount of sorbent and in the presence of different type of waters. In ultrapure water, average recovery percentages of 47%, 97% and 71% were obtained using 100 mg/L of MEG-HA, GO-PEI and GO-CH, respectively. The sorption behaviour of the composites showed that the recovery is more efficient in mineral water, either using MEG-HA or GO-PEI, achieving recovery percentages around 100%. However, in saline water, the recovery percentages decrease to ca. 60 and 50% using 100 mg/L of GO-PEI and MEG-HA, respectively. The results were adjusts using kinetic models of pseudo first order, pseudo second order and Elovich and the sorption mechanism that better described the interaction between the nanocomposites and REEs was chemisorption. The application of the nanocomposites tested for the recovery of rare earth elements from aqueous solutions confirms that the carbon-based composites have a great potential to be used in the recovery of REEsA sociedade nunca foi tão dependente de dispositivos eletrónicos e elétricos como é hoje. Como resultado desta crescente utilização, o lixo eletrónico tornouse um problema mundial, não apenas devido às alterações ambientais que surgiram com o seu tratamento e armazenamento incorreto, mas também porque a quantidade de lixo eletrónico aumenta a cada ano. Outro problema inerente aos dispositivos elétricos e eletrónicos é o facto de dependerem de elementos de terras-raras para serem produzidos. Atualmente, eles são considerados as “vitaminas” da indústria moderna, devido ao seu papel crucial no desenvolvimento de novas tecnologias e às suas propriedades químicas e físicas distintas. No entanto, a elevada procura e os recursos limitados de elementos de terras-raras (REEs), combinados com os problemas ambientais associados à sua exploração pelas atividades de mineração, reforçam a necessidade de desenvolver novas formas de recuperar estes elementos a partir de lixo eletrónico e de águas residuais que os contenham. Portanto, o desenvolvimento de técnicas e materiais de baixo custo para a recuperação destes elementos é extremamente importante. Desta forma, o principal objetivo deste trabalho foi desenvolver materiais compósitos à base de carbono que fossem eficientes para a recuperação de terras-raras. A maioria dos estudos de sorção reportados na literatura foram realizados em água ultrapura e com soluções monoelementares de concentrações elevadas de terras-raras; assim, o objetivo é estudar a recuperação destes elementos em matrizes mais complexas, tais como na presença de outros iões, e usando concentrações mais realistas de terras-raras. Os materiais sintetizados e usados neste trabalho foram a grafite esfoliada magnética funcionalizada com ácidos húmicos (MEG-HÁ), óxido de grafeno funcionalizado com 25% de polietilenimina (GO-PEI) e óxido de grafeno funcionalizado com quitosana (GO-CH) e estes foram avaliados quanto à sua capacidade de recuperação de REEs, utilizando diferentes quantidades de material/sorvente e na presença de diferentes tipos de águas. Em água ultrapura, foram obtidas percentagens médias de recuperação de 47%, 97% e 71%, utilizando 100 mg/L de MEG-HÁ, GO-PEI e GO-CH. O comportamento de sorção dos compósitos permitiu verificar que a recuperação é mais eficiente em água mineral, quer usando MEG-HÁ ou GO-PEI, atingindo percentagens de recuperação de cerca 100%. No entanto, em água do mar, as percentagens de recuperação diminuem para cerca 60 e 50% usando 100 mg/L de GO-PEI e MEG-HÁ, respetivamente. Os resultados foram ajustados utilizando modelos cinéticos de pseudo primeira ordem, pseudo segunda ordem e Elovich e o mecanismo de sorção que melhor descreveu a interação entre os nanocompósitos e as REEs foi a quimiossorção. A aplicação dos nanocompósitos testados para a recuperação de REEs a partir de soluções aquosas confirma que os compósitos MEG-HÁ e GO-PEI têm um elevado potencial para serem utilizados na recuperação de REEs de águasMestrado em Químic

Risk factors associated with the transmission of Brazilian spotted fever in the Piracicaba river basin, State of São Paulo, Brazil

Brazilian spotted fever (BSF) is a disease transmitted by ticks for which the etiological agent is Rickettsia rickettsii. The present essay evaluates the risk factors associated with the transmission of cases of BSF in the time period between 2003 and 2013 in the Piracicaba river basin, state of São Paulo. This essay presents a retrospective study to identify the factors associated with the transmission of cases of BSF among all suspected cases identified by the System for Epidemiological Surveillance of São Paulo (CVE). After the description of temporal distribution (onset of symptoms) and the environmental and demographic variations of the confirmed and discarded cases, a multiple logistic regression model was applied.We searched 569 probable locations of infection (PLI) with 210 (37%) confirmed cases of BSF and 359 (63%) discarded cases. The associated variables for the confirmation of BSF in the multiple logistic model using a confidence interval (CI) of 95% were age (OR = 1.025 CI: 1.015-1.035), the presence of Amblyomma sculptum in the environment (OR = 1.629 CI: 1.097-2.439), the collection of ticks from horses (OR = 1.939 CI: 0.999-3.764), the presence of capybaras (OR = 1.467 CI: 1.009-2.138), an urban environment (OR = 1.515 CI: 1.036-2.231), and the existence of a dirty pasture (OR = 1.759 CI: 1.028-3.003). The factors associated with the confirmation of BSF cases included an urban environment, age, presence of the A. sculptum vector, the collection of ticks from horses, the presence of a capybara population, and a dirty pasture environment4811117CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQNão te

Spin-0 bosons near rotating stars

In this work we study the effects of rotating stars on the behavior of bosons close to their surfaces. For this task, metrics determined by the rotation of these stars will be taken into account. We will consider the Klein-Gordon equation in the Hartle-Thorne metric and in the one proposed by Berti et al. by considering some kinds of stars. Pions and Higgs bosons will be investigated as examples. By solving the equations, the main effect that may be observed is a rotational phase, $\delta_R$, that depends on the angular momentum of the star, $J$, in the wave function of the boson. Corrections of higher orders in $J$ are also investigated

Reviewed evidence about the safety of the daily use of alcohol-based mouthrinses

Current scientific knowledge provides clear evidence that alcohol-based mouthwashes can be beneficial in a daily oral health routine, including dental hygiene and plaque control. Several issues are worth discussing, in spite of the wealth of supporting evidence. Despite some undesirable effects to some people, like burning sensation, and some contraindications, like the use by infants, alcohol addicts and patients with mucosal injuries, there is no reason to avoid the use of alcohol-containing mouthwashes as long as they are used following proper guidance by dental professionals and the manufacturers' instructions. The alleged correlation between oral cancer and alcohol-based mouthrinses presents so little, weak, inconsistent and even contradictory evidence in the literature that any kind of risk warning to patients would be uncalled for. Antimicrobial mouthrinses are safe and effective in reducing plaque and gingivitis, and should be part of a comprehensive oral health care regimen that includes brushing, flossing and rinsing to prevent or minimize periodontal disease

Estabilidade de progênie de Schistosoma mansoni a drogas esquistossomicidas

A suscetibilidade de linhagem brasileira (MAP), nas gerações F1 a F5 de S. mansoni a quatro drogas esquistossomicidas foi descrita em trabalho anterior. Na presente pesquisa os Autores testam a estabilidade da progênie F14 da referida linhagem às quatro drogas e a um novo medicamento, Oltipraz (35,972 RP). Cinco grupos de 12 camundongos infectados com cercárias por meio da imersão da cauda, foram tratados com hycanthone, oxamniquine, niridazole, praziquantel e Oltipraz. Foi utilizado um grupo controle de camundongos infectados e não tratados. A atividade esquistossomicida das drogas foi avaliada pela localização dos vermes no sistema porta, pelas alterações no oograma e percentagem de redução de vermes. A suscetibilidade dos vermes da geração F14 mostrou-se estável em relação àquelas observadas nas progênies F1 a F5; a progênie F14 de vermes foi resistente ao hycanthone e oxamniquine; todavia, for sensível ao niridazole, prazi- quantel e Oltipraz. Os Autores enfatizam a importância do fenômeno de resistência do verme em vista do fato do oxamniquine ser largamente utilizado em áreas do Brasil onde a esquistossomose mansônica é endêmica.The susceptibility of the MAP Brazilian strain (F1 to F5 progenies) of S. mansoni to four antischistosomal drugs has been reported in a previous study. In the present investigation, progeny F14 of the same strain, was tested for stability to the same 4 drugs. A new medication, Oltipraz (35,972 RP), was added to the study. Five groups of 12 mice infected with cercariae by tail immersion were treated with hycanthone, oxamniquine, niridazole, praziquantel and Oltipraz. An untreated group was used as control. Schistosomal activity was assessed by the localization of worms in the portal vein system, by oogram changes, and percentage of parasite reduction. The stability of the susceptibility of progeny F14 did not change in relation to generations F1 to F5; the progeny was resistant to hycanthone and oxamniquine; but sensitive to niridazole, praziquantel and Oltipraz. We emphasize the importance of the phenomenon of resistance of the worm in view of the fact that oxamniquine has been widely used in Brazilian areas where mansonic schistosomiasis is endemic

High Seroprevalence For Rickettsia Rickettsii In Equines Suggests Risk Of Human Infection In Silent Areas For The Brazilian Spotted Fever

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Equines play a role in the epidemiology of Brazilian spotted fever (BSF) since they are a primary host for the tick Amblyomma sculptum. We studied the seroprevalence for three species of Rickettsia in equines in four endemic (with human cases) and in four non-endemic areas (no human cases) in the Piracicaba River Basin, Sao Paulo, Brazil. A serological survey of 504 equines was performed: around 63 animals were sampled in each area and tested through indirect immunofluorescence assay for R. rickettsii, R. parkeri, and R. bellii in 2012-2013. Blood samples were seropositive for 183 equines (36.3%) in which 73 (39.9%) were from non-endemic areas. In the studied sites equines were highly exposed to Rickettsia infection ranging from 6.1% to 54.7%, with Geometric Mean Titers greater in endemic area (p = 0.012). Results suggest that Rickettsia may be more widespread than the surveillance of BSF has detected. These results highlight the need to include data on the seroprevalence of sentinel animals to improve human diagnoses and surveillance in areas with no reported human cases.114National Counsel of Technological and Scientific Development (CNPq) [472573/2011-0]Sao Paulo Research Foundation (FAPESP) [2012/02447-0]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Insucesso na indução de resistência a drogas esquistossomicidas em uma cepa brasileira humana de Schistosoma mansoni

In this work, an attempt was made to induceng resistance to 3 schistosomicidal drugs in a Brazilian strain of S. mansoni, according to the Type II resistance induction scheme proposed by JANSMA et al. in 1977. Three attempts were unsuccessful. The parental generation treated with the drug during the immature stage of the worm was less susceptible to the chemotherapeutic agents than generations F1 and F2. A hypothesis is suggested as an explanation.No presente estudo, realizou-se uma tentativa de indução de resistência a 3 drogas esquistossomicidas em uma cepa brasileira de S. mansoni, segundo o esquema de indução de resistência tipo II preconizado por JANSMA et al. em 1977. Houve insucesso nas 3 tentativas realizadas. A geração parental tratada com a droga durante o estágio imaturo do verme mostrou-se menos suscetível aos quimioterápicos do que as gerações F1 e F2 do verme. Uma hipótese é levantada para a explicação do fato