. The effectiveness of microemulsions (ME) of saponified coconut oil (OCS-ME) and diphenylcarbazide (DC-ME) on a carbon steel corrosion inhibition process was evaluated using an electrochemical method of polarization resistance. The ME was prepared with OCS, butanol, kerosene and saline solutions. OCS-ME and DC-ME showed highest inhibitions effects (77% and 92%, respectively) at lower concentrations (0.5% and 0.48 -0.50%, respectively). The surfactant OCS (in H 2 O) showed lower efficiency (63% at 0.20 -0.25% concentration). The greatest inhibitory effect of DC-ME could be correlated with the chemical structure and the rich O/W ME system, which are very important for adsorption phenomena in interfacial ME systems.Keywords: diphenylcarbazide; saponified coconut oil; microemulsion. INTRODUÇÃOA importância do emprego de materiais metálicos em equipamentos utilizados no setor industrial (têxtil, de alimentos, de petró-leo, dentre outros) que operam em altas temperaturas, justifica a necessidade da otimização de estudos sobre o processo de corrosão, objetivando a minimização de perdas por deterioração de metais. De maneira geral, o estudo de processos corrosivos tem como objetivo principal conhecer e caracterizar os diversos meios agressivos que são responsáveis pelas reações químicas e eletroquímicas causadas em materiais de elevada importância industrial para, em uma etapa subseqüente, reduzir os efeitos com agentes antioxidantes, denominados de inibidores de corrosão.Os processos reacionais que geram a corrosão são geralmente espontâneos e transformam, constantemente, as características fí-sicas e químicas de materiais metálicos e não-metálicos, interferindo, conseqüentemente, em sua estrutura, durabilidade e desempenho. O conhecimento exato dos princípios básicos desses processos é imprescindível para que se estabeleçam considerações qualitativas e quantitativas sobre a cinética de corrosão 1 . Dentre as muitas maneiras de definição de corrosão, pode-se dizer que "a corrosão é a deterioração espontânea de um material, metálico ou não metálico, por ação química ou eletroquímica do meio ambiente, aliada, ou não, a esforços mecânicos" 1,2 . Um dos principais meios causadores de corrosão em instalações industriais (originárias de ferro ou aço) são as salmouras. Um exemplo significativo pode ser dado na indústria de óleos, onde a corrosão em oleodutos é desencadeada por elevados teores de salinidade, necessários para a produção de óleos 3 . Muitas pesquisas têm sido desenvolvidas no sentido de reduzir os efeitos da corrosão. Dentre os processos e métodos mais utilizados destacam-se: o aumento da resistência dos materiais por implantação de sistemas de proteção catódica e anódica, o uso de revestimentos, de agentes inibidores e antioxidantes 1,4 . O uso de inibidores de corrosão caracteriza-se em um dos métodos de grande interesse, já que funcionam como pelícu-las protetoras (sobre áreas anódicas e catódicas) que interferem na ação eletroquímica 1 . Como inibidores de corrosão, moléculas orgâ-nicas fortemente polares s...

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Background and Objectives: Stroke is a leading cause of long-term disability. Rehabilitation involving repetitive, high-intensity, and task-specific exercise is the pathway to restore motor skills. Robotic assistive devices such as Gloreha are increasingly being used in upper limb rehabilitation. The aim of this study is to explore the efficacy of robotic therapy for upper limb rehabilitation using robotic glove (Gloreha) in patients with stroke. Materials and Methods: The patients affected by stroke who were admitted to our rehabilitation unit were studied. Patients were exposed to Gloreha device rehabilitation (30 min/die), physiotherapy (1,5 hours/die), and occupational therapy (30 min/die). We measured the impairment in motor function and muscle tone using the modified Ashworth scale (MAS), the activities of daily living functional independence measure (FIM), and the finger dexterity Nine-Hole Peg test (NHPT). Results: Twelve patients (mean age = 64.5 years; male/female: 8:4) were admitted at the rehabilitation training. We found statistically significant differences between admission and discharged in terms of functional recovery using the FIM scale (pre/M = 88.33; post/M = 117.25, P = 0.01); hand training showed a better outcome using the NHPT (pre/M = 51.8; post/M = 36.33, P = 0.01). No significant changes were observed in terms of spasticity with the MAS (pre/M = 1.25; post/M = 1.08;P > 0.05). Conclusions: Rehabilitation with robotic glove (Gloreha) can positively promote functional recovery of arm function in a patient with stroke.

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In this work, we investigate the use of microemulsions in the solubilization of heavy crude oil fractions, which are responsible for the formation of deposits in petroleum processing operations. Initially, the construction of phase diagrams was addressed, with the intention of determining the area within which microemulsions are formed. Unitol L 90 was used as a non-ionic surfactant. Butan-1-ol and butan-2-ol were tested as co-surfactants. Four different systems were studied: Unitol L 90 + butan-1-ol + water + kerosene (system 1), Unitol L 90 + butan-1-ol + water + xylene (system 2), Unitol L 90 + butan-1-ol + water + 90% kerosene/10% xylene (system 3), and Unitol L 90 + butan-2-ol + water + xylene (system 4). Physical adsorption experiments were carried out with the static method, aiming to simulate natural reservoir conditions. Crude oil samples from the Fazenda Belém field (Rio Grande do Norte State, Brazil) were used and dissolved in xylene. Arenite samples from the Assu (Rio Grande do Norte State) and Botucatu (Paraná State, Brazil) geological formations were tested as rock reservoirs. The adsorption curves featured the “S” profile. The solubilization process was accomplished via the batch method, by varying the stirring time, microemulsion composition, and the solid/solution ratio. The experiments showed that the microemulsions presented high efficiency in the solubilization of crude oil adsorbed on the arenites. In particular, system 2 presented an efficiency as high as 99% when tested on the Assu arenite and 97% on the Botucatu arenite. No significant differences were detected on the extent of solubilization of heavy fractions, by varying the surfactant concentration in the formulations used in this work. Therefore, for economical reasons, it could be suggested that systems containing only 20% in active matter (surfactant plus co-surfactant) are more suitable for applications involving the use of non-ionic microemulsions on the prevention of oil sludge waste formation.

Recebido em 8/3/12; aceito em 27/7/12; publicado na web em 26/11/12 EVALUATION OF ANTICORROSIVE EFFECTIVENESS OF THIOSEMICARBAZONES SOLUBILIZED IN A MICROEMULSION SYSTEM. In this paper, thiosemicarbazones 4-N-cinnamoyl-thiosemicarbazone (CTSC), 4-N-(2'methoxycinnamoyl)-thiosemicarbazone (MCTSC), and 4-N-(4'-hydroxy-3'-methoxybenzoyl)-thiosemicarbazone (HMBTSC) were solubilized in an oil-in-water (O/W) microemulsion system (ME_OCS), forming systems CTSC_ME_OCS, MCTSC_ME_OCS and HMBTSC_ME_OCS. The effectiveness of these systems in the process of inhibiting AISI 1020 carbon steel corrosion was evaluated in a saline solution (NaCl 0.5%), using a galvanostatic method. The tested thiosemicarbazones showed higher inhibitory effects (85.7% for CTSC_ME_OCS, 84.0% for MCTSC_ME_OCS, and 83.3% for HMBTSC_ME_OCS). The surfactant OCS (dissolved in H 2 O) and the ME_OCS system showed lower efficacies, with 71.0% for OCS and 74.0% for ME_OCS system.

Polar microemulsion systems (SME) based on saponified coconut oil (OCS) as surfactant were prepared in order to increase the solubility of the heterocycle isatin (IST) aiming at its application as corrosion inhibitor against AISI 1020 mild steel, in saline medium. The adsorptions phenomena of the tested SME systems (SME-OCS1-IST and SME-OCS2-IST) in the liquid/gas interface were evaluated by surface tension measurements which do not show significant differences in the presence of ion Cl -. The free energy values of the micellization proved the occurrence of spontaneous process. The corrosion inhibition effectiveness of SME-OCS2, SME-OCS1-IST and SME-OCS2-IST samples was evaluated in 0.5% aqueous NaCl using voltammetry linear scan method (LPR). The maximum efficiency findings were 73.2% for SME-OCS2, 88.2% for SME-OCS2-IST and 97.6% for SME-OCS1-IST. The spontaneity of the adsorption phenomena was also observed in the liquid/metal interface by analyzes of the adsorption free energy. In addition, since computational calculations have been found as a very relevant tool in the corrosion field, a theoretical study was performed in attempt to give support to the observed experimental results, in which B3LYP and 6-311++G(d,p) were applied aiming at investigation of geometry, electronic density aspects, HOMO-LUMO energy gap, as well as the binding between isatin and metal surface.Keywords: isatin, microemulsion o/w systems; corrosion inhibitor; saline medium; LPR electrochemical methodology; theoretical study using B3LYP and 6-311++G(d,p). INTRODUÇÃOA corrosão acarreta prejuízos financeiros e operacionais significativos, além de danos ambientais e riscos operacionais. Em função de causar deterioração de equipamentos e estruturas metálicas, o fenômeno da corrosão se destaca como um dos maiores problemas das indústrias da atualidade. O aço-carbono, em função de suas propriedades, simples fabricação e baixo custo, é um dos principais tipos de aço empregados na indústria, no entanto, a exemplo de outros materiais, está sujeito à corrosão por diversos meios. Por esta razão, a demanda, em todo o mundo, por agentes inibidores de corrosão se mostra altamente atrativa para o setor industrial. [1][2][3][4][5][6][7][8] Várias pesquisas vêm sendo desenvolvidas no sentido de controlar a corrosão. Dentre os métodos mais utilizados, destaca-se o uso de inibidores de corrosão por ação de películas protetoras que se adsorvem às áreas anódicas e catódicas do metal, exercendo controle sobre os processos eletroquímicos que desencadeiam a corrosão. Em função da eficácia de filmes protetores que se formam na interface entre o metal e o meio corrosivo, destaca-se o uso de moléculas orgânicas contendo nitrogênio, oxigênio e enxofre.9-15 Esta proteção está vinculada às interações entre heteroátomos presentes em suas estruturas com a superfície do metal, cuja natureza e carga superficial também influenciam diretamente o processo de adsorção.A isatina (IST) é um composto orgânico heterociclo quem vem sendo amplamente utilizado em pesquisas cientí...

Extracts obtained from plants have significantly contributed to the creation of new drugs due to their medicinal properties, which are provided by the presence of bioactive components. This has led to a growing interest from the pharmaceutical industry in using this type of extract for the creation of increasingly advanced medications. The main components sought are antibacterial agents from sustainable and renewable sources, whether of animal or vegetable origin or derived from other natural components. Tissues become a source of microbial proliferation, especially when in contact with the human body, which can cause serious diseases. In line with this, the goal of this research was to create an antibacterial Melon-de-São-Caetano (Momordica charantia) leaf microemulsion for application on material surfaces. This microemulsified system is an effective alternative for solubilizing functional agents, and being thermodynamically stable, it is efficient for long-term use. For this study, an extract of Momordica charantia leaves (EMC) was obtained, and microemulsions with different EMC concentrations (P1, P2, and P3) were produced. The extract and microemulsions were investigated using Fourier Transform Infrared (FTIR) spectroscopy, particle size, zeta potential, thermal stress, pH, electrical conductivity, Transmission Electron Microscopy (TEM), and antibacterial analysis (Staphylococcus aureus). In summary, the proposed objective was met, and EMC, SME, and the P2 and P3 microemulsions showed positive results against S. aureus, with the P3 microemulsified system being the most effective with a 12.5 mm inhibition halo. Therefore, the product developed in this research has the potential for application on surfaces, providing antibacterial action.