962 resultados para octadecyl trimethylammonium bromide


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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Introduction: The aim of this study was to assess the influence of curing time and power on the degree of conversion and surface microhardness of 3 orthodontic composites. Methods: One hundred eighty discs, 6 mm in diameter, were divided into 3 groups of 60 samples according to the composite used-Transbond XT (3M Unitek, Monrovia, Calif), Opal Bond MV (Ultradent, South Jordan, Utah), and Transbond Plus Color Change (3M Unitek)-and each group was further divided into 3 subgroups (n = 20). Five samples were used to measure conversion, and 15 were used to measure microhardness. A light-emitting diode curing unit with multiwavelength emission of broad light was used for curing at 3 power levels (530, 760, and 1520 mW) and 3 times (8.5, 6, and 3 seconds), always totaling 4.56 joules. Five specimens from each subgroup were ground and mixed with potassium bromide to produce 8-mm tablets to be compared with 5 others made similarly with the respective noncured composite. These were placed into a spectrometer, and software was used for analysis. A microhardness tester was used to take Knoop hardness (KHN) measurements in 15 discs of each subgroup. The data were analyzed with 2 analysis of variance tests at 2 levels. Results: Differences were found in the conversion degree of the composites cured at different times and powers (P < 0.01). The composites showed similar degrees of conversion when light cured at 8.5 seconds (80.7%) and 6 seconds (79.0%), but not at 3 seconds (75.0%). The conversion degrees of the composites were different, with group 3 (87.2%) higher than group 2 (83.5%), which was higher than group 1 (64.0%). Differences in microhardness were also found (P < 0.01), with lower microhardness at 8.5 seconds (35.2 KHN), but no difference was observed between 6 seconds (41.6 KHN) and 3 seconds (42.8 KHN). Group 3 had the highest surface microhardness (35.9 KHN) compared with group 2 (33.7 KHN) and group 1 (30.0 KHN). Conclusions: Curing time can be reduced up to 6 seconds by increasing the power, with a slight decrease in the degree of conversion at 3 seconds; the decrease has a positive effect on the surface microhardness.

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A synergistic electrocatalytic effect was observed in sensors where two electrocatalytic materials (functionalized gold nanoparticles and lutetium bisphthalocyanine) were co-deposited using the Langmuir-Blodgett technique. Films were prepared using a novel method where water soluble functionalised gold nanoparticles [(11-mercaptoundecyl)tetra(ethylene glycol)] (SAuNPs) were inserted in floating films of lutetium bisphthalocyanine (LuPc2) and dimethyldioctadecylammonium bromide (DODAB) as the amphiphilic matrix. The formation of stable and homogeneous mixed films was confirmed by pi-A isotherms, BAM, UV-vis and Raman spectroscopy, as well as by SEM and TEM microscopy. The synergistic effect towards hydroquinone of the electrodes modified with LuPc2:DODAB/SAuNP was characterised by an increase in the intensity of the redox peaks and a reduction of the overpotential. This synergistic electrocatalytic effect arose from the interaction between the SAuNPs and the phthalocyanines that occur in the Langmuir-Blodgett films and from the high surface area provided by the nanostructured films. The sensitivity increased with the amount of LuPc2 and SAuNPs inserted in the films and limits of detection in the range of 10(-7) mol L-1 were attained. (C) 2014 Elsevier B.V. All rights reserved.

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ObjectivesIn traditional medicine, plants have formed the basis of sophisticated systems that have been in existence for thousands of years and still provide mankind with new remedies. Cymbopogon martinii, known as palmarosa, has been used in aromatherapy as a skin tonic due to its antimicrobial properties. It has also used in Ayurvedic medicine for skin problems and to relieve nerve pain. The immunomodulatory action of C.martinii essential oil (EO) and geraniol was evaluated regarding the production of pro- and anti-inflammatory cytokines (tumour necrosis factor (TNF)- and IL-10, respectively) by human monocytes in vitro.MethodsMonocyte cultures were incubated with EO or geraniol. After 18h, cytotoxicity assays were performed using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide method, and cytokine production was determined by ELISA.Key findingsThe variables showed no cytotoxic effects on monocytes. TNF- production was not affected by C.martinii and geraniol, and only the concentration of 5g/ml of C.martinii stimulated its production. On the other hand, all concentrations of C.martinii and geraniol increased IL-10 production by human monocytes.ConclusionsData showed that noncytotoxic concentrations of EO and geraniol exerted an anti-inflammatory action by increasing IL-10 production; moreover, geraniol seemed to be probably responsible for EO immunomodulatory activity in our assay condition.

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Seizure is a clinical manifestation of abnormal neuronal hyperactivity of the cerebral cortex, presentation clinical varies according to the location and extent of the brain. The classic seizure begins with an inicial period, named prodrome, followed by the aura, the ictus and finally the post-ictus phase. Seizures can be generalized or focal/partial types. Focal seizures with secondary generalization are the most common type in dogs. The seizure can be divided etiologically in intracraneal (idiopathic epilepsy; sintomatic; probably sintomatic epilepsy) and extracraneal disorders. After determining the etiology of seizures and critical analysis of the frequency, severity, and worry they cause to the owner, you should make the decision whether to launch an anticonvulsant drug therapy. Although the ideal is the elimination of seizures, the real goal should be to decrease the frequency and intensity of crises, without affecting the quality of life of patients taking the drugs used side effects acceptable. The veterinary should consider the bioavailability of the drug, contraindications, toxicity, drug interactions, the amount of daily administration, the availability of the owner and the cost of therapy. Seizures can be controlled in about 70- 80% of the dogs and in the majority of the cats when treated with Phenobarbital alone. Addition of a second drug (usually potassium bromide), decreases the number of seizures in more that 50% in about 70-80% of dogs. However, approximately 20-30% of dogs are refractory to this treatment. In these cases, it will be necessary to think in other pharmacological alternatives, like felbamate, gabapentin, levetiracetam, zonisamid, among others. It has been concluded that... (Complete abstract click eletronic access below)

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This work presents a study of the absorption refrigeration system and the modeling and evaluation of two cycles using the binary solutions water-lithium bromide and ammonia-water for an equipment to be used in small size plants like residences. The study and evaluation aims the complete understanding of all parts of the system and the influence of each one of them as well as the spread of the knowledge to raise the use of this type of equipment in all sizes in order to decrease the energetic consumption of plants of all scales and making viable the alternative sources. The study is done in each element of the cycle separately and in some auxiliary equipments required in the operation such as the main power source, the solar collector. The software used for modeling, with emphasis on thermal part, was the EES (Engineering Equation Solver), that permitted the thermal balance calculus and acquisition of the used fluids properties. The results obtained for the equipment shows the system is more complex than the widely used in business, however, it can be viable and represents an alternative to increase the energetic efficiency

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)