Microencapsulation of herbicide MCPA with native beta-cyclodextrin and its methyl and hydroxypropyl derivatives: An experimental and theoretical investigation

When a pesticide is released into the environment, most of it is lost before it reaches its target. An effective way to reduce environmental losses of pesticides is by using controlled release technology. Microencapsulation becomes a promising technique for the production of controlled release agricultural formulations. In this work, the microencapsulation of chlorophenoxy herbicide MCPA with native b-cyclodextrin and its methyl and hydroxypropyl derivatives was investigated. The phase solubility study showed that both native and b-CD derivatives increased the water solubility of the herbicide and inclusion complexes are formed in a stoichiometric ratio of 1:1. The stability constants describing the extent of formation of the complexes have been determined by phase solubility studies. 1H NMR experiments were also accomplished for the prepared solid systems and the data gathered confirm the formation of the inclusion complexes. 1H NMR data obtained for the MCPA/CDs complexes disclosed noticeable proton shift displacements for OCH2 group and H6 aromatic proton of MCPA provided clear evidence of inclusion complexation process, suggesting that the phenyl moiety of the herbicide was included in the hydrophobic cavity of CDs. Free energy molecular mechanics calculations confirm all these findings. The gathered results can be regarded as an essential step to the development of controlled release agricultural formulations containing herbicide MCPA.

Phase behavior of shape-changing spheroids

We introduce a simple model for a biaxial nematic liquid crystal. This consists of hard spheroids that can switch shape between prolate (rodlike) and oblate (platelike) subject to an energy penalty Δε. The spheroids are approximated as hard Gaussian overlap particles and are treated at the level of Onsager's second-virial description. We use both bifurcation analysis and a numerical minimization of the free energy to show that, for additive particle shapes, (i) there is no stable biaxial phase even for Δε=0 (although there is a metastable biaxial phase in the same density range as the stable uniaxial phase) and (ii) the isotropic-to-nematic transition is into either one of two degenerate uniaxial phases, rod rich or plate rich. We confirm that even a small amount of shape nonadditivity may stabilize the biaxial nematic phase.

Schistosoma mansoni: protective immunity in mice cured by chemotherapy at the chronic phase of the disease

Aiming at demonstrating a decrease of acquired immunity after chemotherapeutic cure, a group of mice was infected with 25 Schistosoma mansoni cercariae (LE strain). A part of these animals was treated with 400 mg/kg oxamniquine, at 120 days after infection. Challenge infections were carried out at 45, 90 and 170-day-intervals after treatment (185, 210 and 290 days after primoinfection, respectively). Recovery of worms at 20 days after reinfections showed that a residual immunity remains up to 90 days after treatment, and disappears at 170 days after cure. Using the ELISA method, it was possible to detect a decrease of antibody levels (total IgG) in the treated group, when antigens from different evolutive stages of S. mansoni were used. The epidemiological implications of the present results, and the possible mechanisms involved in the decrease of acquired immunity after treatment are discussed.

Analysis of Forest Fires by means of Pseudo Phase Plane and Multidimensional Scaling Methods

Forest fires dynamics is often characterized by the absence of a characteristic length-scale, long range correlations in space and time, and long memory, which are features also associated with fractional order systems. In this paper a public domain forest fires catalogue, containing information of events for Portugal, covering the period from 1980 up to 2012, is tackled. The events are modelled as time series of Dirac impulses with amplitude proportional to the burnt area. The time series are viewed as the system output and are interpreted as a manifestation of the system dynamics. In the first phase we use the pseudo phase plane (PPP) technique to describe forest fires dynamics. In the second phase we use multidimensional scaling (MDS) visualization tools. The PPP allows the representation of forest fires dynamics in two-dimensional space, by taking time series representative of the phenomena. The MDS approach generates maps where objects that are perceived to be similar to each other are placed on the map forming clusters. The results are analysed in order to extract relationships among the data and to better understand forest fires behaviour.

Localization system for pedestrians based on sensor and information fusion

Nowadays there is an increase of location-aware mobile applications. However, these applications only retrieve location with a mobile device's GPS chip. This means that in indoor or in more dense environments these applications don't work properly. To provide location information everywhere a pedestrian Inertial Navigation System (INS) is typically used, but these systems can have a large estimation error since, in order to turn the system wearable, they use low-cost and low-power sensors. In this work a pedestrian INS is proposed, where force sensors were included to combine with the accelerometer data in order to have a better detection of the stance phase of the human gait cycle, which leads to improvements in location estimation. Besides sensor fusion an information fusion architecture is proposed, based on the information from GPS and several inertial units placed on the pedestrian body, that will be used to learn the pedestrian gait behavior to correct, in real-time, the inertial sensors errors, thus improving location estimation.

Dual-phase inkjet printed electrochromic layers based on PTA and WOX/TiO2 nanoparticles for electrochromic applications

Thesis submitted in Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa for the degree of Master in Materials Engineering

Phase behaviour of alternative solvents

Dissertation presented to obtain the Ph.D. degree in Chemistry (Physical Chemistry) at the Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa

Comparison of Disposable Pipette Extraction and Dispersive Solid-Phase Extraction in the QuEChERS Method for Analysis of Pesticides in Strawberries

In this study, we sought to assess the applicability of GC–MS/MS for the identification and quantification of 36 pesticides in strawberry from integrated pest management (IPM) and organic farming (OF). Citrate versions of QuEChERS (quick, easy, cheap, effective, rugged and safe) using dispersive solid-phase extraction (d-SPE) and disposable pipette extraction (DPX) for cleanup were compared for pesticide extraction. For cleanup, a combination of MgSO4, primary secondary amine and C18 was used for both the versions. Significant differences were observed in recovery results between the two sample preparation versions (DPX and d-SPE). Overall, 86% of the pesticides achieved recoveries (three spiking levels 10, 50 and 200 µg/kg) in the range of 70–120%, with <13% RSD. The matrix effects were also evaluated in both the versions and in strawberries from different crop types. Although not evidencing significant differences between the two methodologies were observed, however, the DPX cleanup proved to be a faster technique and easy to execute. The results indicate that QuEChERS with d-SPE and DPX and GC–MS/MS analysis achieved reliable quantification and identification of 36 pesticide residues in strawberries from OF and IPM.

Ajustes Posturais dos músculos da tibiotársica em indivíduos com Doença de Parkinson durante o sit-to-stand

Introdução: Os ajustes posturais antecipatórios (APAs) são essenciais para o movimento típico, estando alterados nas doenças neuro degenerativas como a doença de Parkinson (DP) Objectivo(s): Estudar os early postural adjustments e os APAs em indivíduos com DP durante o sentar para levantar (STS), com e sem dupla tarefa. Métodos: Foi recolhida a atividade eletromiográfica (EMG) dos músculos tibial anterior, solear e gastrocnémio medial, em indivíduos com e sem DP (9 em cada grupo), durante o STS. Este foi determinado pelo deslocamento antero posterior do centro de pressão através da plataforma de forças, sendo a tarefa cognitiva dada pelo stroop colour word interference test. Os ajustes posturais foram avaliados pelo tempo de ativação e pela atividade EMG relativa, bem como pela análise da co ativação agonista/antagonista. Resultados: Não foram encontradas diferenças estatisticamente significativas entre o grupo de controlo e o grupo com DP em nenhuma das variáveis analisadas Há uma tendência para o grupo com DP apresentar APAs mais cedo na tarefa simples, mantendo atividade muscular durante mais tempo e com maior atividade EMG relativa que o grupo controlo. Na dupla tarefa mantém-se essa tendência, exceto o tempo de ativação ser mais próximo do levante. Conclusão: Os défices posturais decorrentes da doença de Parkinson parecem não ser evidenciados na primeira fase do sit-to-stand.

Pulmonary manifestations in the initial phase of schistosomiasis mansoni

The clinical and radiological pulmonary manifestations in the initial phase of schistosomiasis mansoni were studied in thirty previously healthy individuals who were simultaneously infected. The findings were compared with those concerning a control group and related to possible pathogenetic factors. The respiratory manifestations were of light or of moderate intensity, the dry cough being the most common symptom. The significant radiological alterations were: thickening of bronchial walls and beaded micronodulation, predominantly localized in the lower pulmonary fields. It was observed significant association between wheezing and IgE levels, estimated by the area of immediate intradermal reaction, as well as between the number of blood eosinophils and the occurrence of radiological changes. Moreover, there was correlation between the worm burden and the presence of wheezing, thoracic pain and beaded micronodulation. Thus, the clinical and radiological pulmonary manifestations described are significant part of the initial phase of schistosomiasis mansoni and present the worm burden, eosinophilia and levels of IgE as probable pathogenetic factors.

Egg excretion in the initial phase of experimental murine schistosomiasis mansoni: stability and association with worm burden

Stability of faecal egg excretion and correlation with results related to worm burden at the initial phase of schistosomiasis mansoni were observed in two groups of mice infected with different Schistosoma mansoni cercarial burdens, by means of analysis of quantitative parasitological studies and schistosome counts after perfusion. Thus, it may be stated that few quantitative parasitological stool examinations could be sufficient to express the infection intensity at the initial phase, on the same grounds that it was already demonstrated at the chronic phase. Furthermore, it is confirmed that the use of the number of eggs passed in the faeces as a tool to estimate the worm burden at the initial phase of schistosome infection is adequate.

Dot-ELISA for the detection of anti-Cysticercus cellulosae antibodies in cerebrospinal fluid using a new solid phase (resin-treated polyester fabric) and Cysticercus longicollis antigens

A dot-ELISA was developed for the detection of antibodies in CSF in the immunologic diagnosis of human neurocysticercosis, using antigen extracts of the membrane and scolex of Cysticercus cellulosae (M+S-Cc) and, alternately, membrane (M) and vesicular fluid (VF) of Cysticercus longicollis (Cl) covalently bound to a new solid phase consisting of polyester fabric treated with N-methylol-acrylamide resin (dot-RT). The test was performed at room temperature, with reduced incubation times and with no need for special care in the manipulation of the support. The sensitivity rates obtained were 95.1% for antigen Cc and 97.6% for antigen Cl. Specificity was 90.6% when Cc was used, and 96.9% and 100% when M-Cl and VF-Cl were used, respectively. No significant differences in titer were observed between tests carried out with homologous and heterologous antigens. The low cost and easy execution of the dot-RT test using antigen extracts of Cysticercus longicollis indicate the test for use in the immunodiagnosis of human neurocysticercosis.

Polyvinyl alcohol-glutaraldehyde as solid-phase in Elisa for Schistosomiasis

Soluble adult Schistosoma mansoni antigen preparation (SWAP) was covalently fixed onto polyvinyl alcohol-glutaraldehyde discs and an enzyme linked-immunosorbent assay (ELISA) was set up. The best conditions for the assay were established and it was found that small amount of antigen such as 1.5 µg was required. A comparison between this procedure and the conventional ELISA was proceeded. A reliable method of antigen immobilization was achieved and the low prices of the employed reagents are economically attractive

Inspeção, Diagnóstico e Reparação de Estruturas de Betão Armado

O mercado da reabilitação de estruturas em Portugal está em voga, sendo um nicho de mercado com evolução galopante nos últimos anos fruto da consciencialização das entidades responsáveis, assim como das necessidades de intervir no parque edificado cada vez mais degradado, resultando num estímulo para o mercado da construção face ao seu estado atual. As causas associadas à degradação prematura dos materiais estruturais resultam de erros de conceção e execução, assim como do facto de muitas estruturas de betão armado do parque habitacional edificado nas décadas de 60 e 70, estarem a atingir o fim do seu período de vida útil. Na avaliação do estado de degradação de estruturas de betão armado aconselha-se a utilização de ensaios não destrutivos, uma vez que permitem efetuar um diagnóstico com resultados positivos salvaguardando a integridade da estrutura. A norma EN 1504“Produtos e Sistemas para a proteção e reparação de estruturas de betão” estipula os procedimentos de execução, as características dos materiais mais adequados a cada tipo de projeto, assim como a divisão do seu encadeamento em 5 fases. O caso prático apresentado é um edifício de prestação de serviços municipais, tendo sido aplicado com o maior rigor possível as fases de inspeção, diagnóstico, deliberação e reparação. Foi efetuada uma fase de diagnóstico, de carácter visual assim como de caracterização física dos elementos estruturais em betão armado através de ensaios “in situ”. A estrutura avaliada apresenta debilidades e um estado de degradação acelerado, pelo que urge uma intervenção de reparação por forma a repor a estrutura com as características da sua conceção, salvaguardando a segurança das pessoas e bens.