Density of the reference Ionic liquid [C6mim][NTf2] at high pressures

Workshop realizado em Lisboa de 2-3 Fevereiro de 2012Density of the ionic liquid [C6mim][NTf2] – a reference ionic liquid for thermophysical properties, as proposed by IUPAC8 was measured using an Anton Paar density meter DMA HP. The basic experimental setup was described previously, and the modifications introduced in order to avoid water contamination of the sample are described in the presentation. The measurements were performed in the temperature range (283.15 ≤ T ≤ 353.15) K and at pressures (0.1 ≤ p ≤ 65) MPa. The water content of the samples was measured by Karl-Fisher coulometry, both before and after the measurements. As the viscosity of that ionic liquid is much higher than the viscosity of the fluids used in the calibration of the densimeter, a correction of the results became necessary, to account for the consequent error in the period of oscillation of the U-tube. For this purpose, the viscosity effect on the density measurements on the Anton Paar DMA HP was quantified using the viscosity standard specimen (200GW) from ZMK, GmbH. The experimental determination of the viscosity correction to the measured density is described and also the preliminary results of the density of [C6mim][NTf2] are compared with literature values

High-viscosity reference liquids at high pressures

Encontro realizado no Porto a 31 de agosto de 201

Viscosity measurements on Ionic liquids : a cautionary tale

The vibrating-wire viscometer has proven to be an exceedingly effective means of determining the viscosity of liquids over a wide range of temperature and pressure. The instrument has a long history but a variety of technological and theoretical developments over a number of years have improved its precision and most recently have enabled absolute measurements of high accuracy. However, the nature of the electrical measurements required for the technique has inhibited its widespread use for electrically conducting liquids so that there have been only a limited number of measurements. In the particular context of ionic liquids, which have themselves attracted considerable attention, this is unfortunate because it has meant that one primary measurement technique has seldom been employed for studies of their viscosity. In the last 2 years systematic efforts have been made to explore the applicability of the vibrating-wire technique by examining a number of liquids of increasing electrical conductivity. These extensions have been successful. However, in the process we have had cause to review previous studies of the viscosity and density of the same liquids at moderate temperatures and pressures and significant evidence has been accumulated to cause concern about the application of a range of viscometric techniques to these particular fluids. Because the situation is reminiscent of that encountered for a new set of environmentally friendly refrigerants at the end of the last decade, in this paper the experimental methods employed with these liquids have been reviewed which leads to recommendations for the handling of these materials that may have consequences beyond viscometric measurements. In the process new viscosity and density data for 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide [C6mim][NTf2], 1-ethyl-3-methylimidazolium ethyl sulfate [C2mim][EtSO4], and 1-ethyl-3-methylpyridinium ethyl sulfate [C2mpy][EtSO4] have been obtained

Viscosity reference liquids for industrial applications

Conferência realizada no Porto de 31 de agosto a 4 de setembro de 201

On the mobility of dialkyl adipates by PFGSE NMR, computer simulations and other property measurement methods

Encontro realizado em Alacalá de Henares (Madrid), de 22 a 25 de Setembro de 2014Dialkyl adipates are a class of esters materials used as components of lubricants and plasticizers. Diffusion of plasticizers in polymers is a complex process that is difficult to study [1]. As a contribution to understand this phenomenon, the self-diffusion coefficients of five dialkyl adipates (dimethyl, diethyl, dipropyl, dibuthyl and bis(2-ethylhexyl)) were measured by the PFGSTE method in the temperature range 20 to 60ºC. It was shown that these compounds follow the Stokes-Einstein equation [2]. In effect, the self-diffusion coefficients change linearly with T.η-1(η is the viscosity). The dependence of the activation energies for self-diffusion is discussed in terms of size and branching of the alkyl chains of the adipates. Molecular dynamics (MD) simulations were done for these sytems in order to predict the diffusion coefficients as a function of temperature [3]. Acknolwedgements: This work was supported by the Strategic Projects PEst-OE/QUI/UI0100/2011 and PEst-OE/QUI/ UI0100/2013, both funded by Fundação para a Ciência e a Tecnologia (FCT, Portugal). We thank also FCT for funding the NMR facility through Project RECI/QEQ-QIN/0189/2012. References: [1] Rahman M.; Brazel C. S., Prog. Polym. Sci. 2004, 29, 1223–1248. [2] Price W.S, NMR Studies of Translation Motion, Cambridge University Press, Cambridge, 2009. [3] Pereira, L. A. M.; Martins, L. F. G.; Ascenso, J. R; Morgado, P.; Ramalho, J. P. P.; Filipe, E. J. M., J. Chem. Eng. Data 2014, accepted for publication

Lesão expansiva cerebral devida a citomegalovírus: relato de caso e revisão da literatura

Cytomegalovirus (CMV) disease in acquired immunodeficiency syndrome (AIDS) patients most commonly presents as chorioretinitis and gastro-intestinal infection. Neurological involvement due to CMV may cause several clinical presentations: polyradiculitis, myelitis, encephalitis, ventriculo-encephalitis, and mononeuritis multiplex. Rarely, cerebral mass lesion is described. We report a 39 year-old woman with AIDS and previous cerebral toxoplasmosis. She presented with fever, seizures, and vulval ulcers. Her chest X-ray showed multiple lung nodules, and a large frontal lobe lesion was seen in a brain computed tomography scan. She underwent a brain biopsy through a frontal craniotomy, but her condition deteriorated and she died in the first postoperative day. Histopathological studies and immunohistochemistry disclosed CMV disease, and there was no evidence of cerebral toxoplasmosis, bacterial, mycobacterial or fungal infection. CMV disease should be considered in the differential diagnosis of cerebral mass lesion in AIDS patients. High suspicion index, timely diagnostic procedures (surgical or minimally invasive), and proper utilization of prophylactic and therapeutic medication could improve outcome of these patients.As doenças causadas pelo citomegalovírus (CMV) em pacientes com a síndrome da imunodeficiência adquirida apresentam-se principalmente como corioretinite ou comprometimento gastrointestinal. No sistema nervoso central, o CMV pode causar diversas síndromes clínicas: poliradiculite, mielite, encefalite, ventrículo-encefalite e mononeurite múltipla. Raramente, lesões expansivas cerebrais são descritas. Os autores relatam o caso de uma paciente de 39 anos com antecedentes de infecção pelo HIV e toxoplasmose cerebral, que apresentou-se com febre, convulsões e úlceras vulvares. O raios-X de tórax demonstrou múltiplos nódulos pulmonares e a tomografia computadorizada de crânio evidenciou extensa lesão no lobo frontal esquerdo. Após ser submetida à craniotomia, evoluiu com piora clínica, falecendo no primeiro dia de pós-operatório. Os estudos histopatológicos e imunohistoquímicos demonstraram doença citomegálica. Foram excluídas toxoplasmose cerebral e infecção bacteriana, micobacteriana ou fúngica. Concluímos que, embora seja extremamente raro, o CMV deve ser considerado no diagnóstico diferencial das lesões expansivas cerebrais em pacientes com infecção pelo HIV. Um elevado índice de suspeita, procedimentos diagnósticos oportunos (cirúrgicos ou minimamente invasivos), e o adequado uso de antivirais (terapêuticos e profiláticos) podem melhorar o prognóstico desta letal manifestação

Development of biocompatible plasmonic thin films composed of noble metal nanoparticles embedded in a dielectric matrix to enhance Raman signals

This work focused on the production of nanocomposite thin films, composed of noble nanoparticles embedded in a dielectric matrix, to be tested as biocompatible plasmonic platforms for detection of molecules using Surface Enhance Raman Spectroscopy (SERS). Three different thin films systems were deposited by reactive DC magnetron sputtering, namely Au-Al2O3, Au-TiO2 and Ag-TiO2. The depositions were followed by a thermal treatment at different temperatures to promote the growth of the nanoparticles. Localized Surface Plasmon Resonance (LSPR) bands appeared already at 300 °C, related to the presence of Au nanoparticles, and at 500 °C in the case of Ag nanoparticles. Furthermore, at 700 °C, the Ag-TiO2 films showed a broadband optical response due to the formation of Ag clusters at the film's surface. The biological experiments showed that the presence of the thin films didn't affect the growth of C. albicans, which is very convenient if one needs to detect low concentrations of this microorganism using SERS platforms. As for the SERS measurements, an enhancement of R6G Raman spectra intensity was clearly perceivable, but only for the TiO2 matrix. Furthermore, the application of a plasma treatment allowed to better expose the nanoparticles, providing a further enhancement of Raman signals.FCT - Fundação para a Ciência e a Tecnologia (PTDC/FIS-NAN/1154/2014

Different Cleat Models do Not Influence Side Hop Test Performance of Soccer Players with and without Chronic Ankle Instability

The lateral ankle sprain is one of the most common sport injury, representing 10-30% of all musculoskeletal disorders. The lateral ankle sprain is induced by sport gestures involving changes of direction and landing manoeuvres and constitutes a risk factor for the occurrence of chronic ankle instability. Although cleat models and performance have been already explored, no study has evaluated this relationship in athletes with chronic ankle instability. Therefore, the purpose of the study was to analyse the influence of different soccer cleat models on Side Hop Test performance of athletes with and without chronic ankle instability. Thirty-nine athletes were divided into two groups, a chronic ankle instability group (n = 20) and a healthy group (n = 19). Each participant performed the Side Hop Test, executing 10 consecutive jumps on dry artificial grass with 4 cleat models. The Qualisys System and two force platforms were used to analyse the test runtime, the distance travelled and the mean velocity. No statistically significant interaction was observed between the group and the cleat model for all variables evaluated. In addition, no differences were observed between models or groups. In this specific test, performance does not seem to be influenced by different cleat models on dry artificial grass in athletes with and without chronic ankle instability.info:eu-repo/semantics/publishedVersio

Does the cleat model interfere with ankle sprain risk factors in artificial grass?

Background: The cleats-surface interaction has been described as a possible risk factor for lateral ankle sprain. However, their interaction is still unknown in individuals with chronic ankle instability. The purpose of this study was to determine the influence of different soccer cleats on kinematic, kinetic and neuromuscular ankle variables on artificial grass in soccer players with and without chronic ankle instability. Methods: Eighty-two amateur athletes divided in two groups: 40 with chronic ankle instability and 42 without chronic ankle instability. All subjects performed 2 series of 6 consecutive crossover jumps with dominant foot, each one with one of the four models of cleats (Turf, Artificial grass, Hard and Firm ground). Cleat and group main effect and interactions of kinematic, kinetic and neuromuscular variables were analyzed according to factorial repeated measures ANOVA. Findings: No statistically significant cleat and group main effect and interactions were identified in kinematic, kinetic and electromyographic magnitude of the peroneal muscles. A main effect of the group was observed for peroneus longus activation time for TF model (p=0.010). Interpretation: In soccer players, the contributor variables for ankle sprain were not influenced by the kind of soccer cleat used in a functional jump test on artificial grass. However, players with chronic ankle instability present delayed postural adjustments in peroneus longus with the TF model compared to players without chronic ankle instability.info:eu-repo/semantics/publishedVersio

Does the cleat model interfere with ankle sprain risk factors in artificial grass?

Background: The cleats-surface interaction has been described as a possible risk factor for lateral ankle sprain. However, their interaction is still unknown in individuals with chronic ankle instability. The purpose of this study was to determine the influence of different soccer cleats on kinematic, kinetic and neuromuscular ankle variables on artificial grass in soccer players with and without chronic ankle instability. Methods: Eighty-two amateur athletes divided in two groups: 40 with chronic ankle instability and 42 without chronic ankle instability. All subjects performed 2 series of 6 consecutive crossover jumps with dominant foot, each one with one of the four models of cleats (Turf, Artificial grass, Hard and Firm ground). Cleat and group main effect and interactions of kinematic, kinetic and neuromuscular variables were analyzed according to factorial repeated measures ANOVA. Findings: No statistically significant cleat and group main effect and interactions were identified in kinematic, kinetic and electromyographic magnitude of the peroneal muscles. A main effect of the group was observed for peroneus longus activation time for TF model (p=0.010). Interpretation: In soccer players, the contributor variables for ankle sprain were not influenced by the kind of soccer cleat used in a functional jump test on artificial grass. However, players with chronic ankle instability present delayed postural adjustments in peroneus longus with the TF model compared to players without chronic ankle instability.info:eu-repo/semantics/publishedVersio