1-Ethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide as solvent for the separation of aromatic and aliphatic hydrocarbons by liquid extraction - extension to C-7- and C-8-fractions

The ionic liquid 1-ethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide ([C(2)mim][NTf2]) was tested as solvent for the separation of aromatic and aliphatic hydrocarbons containing 7 or 8 carbon atoms (the C-7- and C-8-fractions). The liquid-liquid equilibria (LLE) of the ternary systems (heptane + toluene + [C(2)mim][NTf2]) and (octane + ethylbenzene + [C(2)mim][NTf2]), at 25 degrees C, were experimentally determined. The performance of the ionic liquid as the solvent in such systems was evaluated by means of the calculation of the solute distribution ratio and the selectivity. The results were compared to those previously reported for the extraction of benzene from its mixtures with hexane by using the same ionic liquid, therefore analysing the influence of the size of the hydrocarbons. It was found that the ionic liquid is also good for the extraction of C-7- and C-8- fraction aromatic compounds, just a greater amount of ionic liquid being needed to perform an equivalently efficient separation than for the C-6-fraction. It is also discussed how [C(2)mim][NTf2] performs comparably better than the conventional solvent sulfolane. The original 'Non-Random Two-Liquid' (NRTL) equation was used to adequately correlate the experimental LLE data.

Analysis of Betaine and Choline Contents of Aleurone, Bran, and Flour Fractions of Wheat (Triticum aestivum L.) Using 1H Nuclear Magnetic Resonance (NMR) Spectroscopy

In conventional milling, the aleurone layer is combined with the bran fraction. Studies indicate that the bran fraction of wheat contains the majority of the phytonutrients betaine and choline, with relatively minor concentrations in the refined flour. This present study suggests that the wheat aleurone layer (Triticum aestivum L. cv. Tiger) contains the greatest concentration of both betaine and choline (1553.44 and 209.80 mg/100 g of sample, respectively). The bran fraction contained 866.94 and 101.95 mg/100 g of sample of betaine and choline, respectively, while the flour fraction contained 23.30 mg/100 g of sample (betaine) and 28.0 mg/100 g of sample (choline). The betaine content for
the bran was lower, and the choline content was higher compared to previous studies, although it is known that there is large variation in betaine and choline contents between wheat cultivars. The ratio of betaine/choline in the aleurone fraction was approximately 7:1; in the bran, the ratio was approximately 8:1; and in the flour fraction, the ratio was approximately 1:1. The study further
emphasizes the superior phytonutrient composition of the aleurone layer.
INTRODUCTION
Wheat is a valuable source of betaine, choline (1, 2), B
vitamins, vitamin E, and a number of minerals, including iron,
zinc, magnesium, and phosphorus (3). Epidemiological studies
indicate that whole-grain consumption is protective against
several chronic diseases (4-12). It has not been fully elucidated
how whole-grain cereals or specific fractions (13) exert their
protective effect, but it is thought to be due to their content of
several nutrients associated with the reduced risk of disease.
Conventionally, whole grain is separated during milling into
bran, germ, and flour (14). The nutrient composition of these
fractions differ markedly; refined wheat flour contains approximately
50% less vitamins and minerals than whole-grain
flour (

Comparison of granulometric methods and sampling strategies used in marine habitat classification and Ecological Status assessment

Sediment particle size analysis (PSA) is routinely used to support benthic macrofaunal community distribution data in habitat mapping and Ecological Status (ES) assessment. No optimal PSA Method to explain variability in multivariate macrofaunal distribution has been identified nor have the effects of changing sampling strategy been examined. Here, we use benthic macrofaunal and PSA grabs from two embayments in the south of Ireland. Four frequently used PSA Methods and two common sampling strategies are applied. A combination of laser particle sizing and wet/dry sieving without peroxide pre-treatment to remove organics was identified as the optimal Method for explaining macrofaunal distributions. ES classifications and EUNIS sediment classification were robust to changes in PSA Method. Fauna and PSA samples returned from the same grab sample significantly decreased macrofaunal variance explained by PSA and caused ES to be classified as lower. Employing the optimal PSA Method and sampling strategy will improve benthic monitoring. © 2012 Elsevier Ltd.

Accessing prospective early years’ teachers’ knowledge on fractions in order to design tasks for developing teachers’ MKT

Fractions is perhaps one of the most complex and difficult topics pupils explore in the early years of schooling. Difficulties in learning this topic may have its genesis in the fact that fractions comprise a multifaceted construct (Kieren, 1995) or can be conceived as being grounded in the instructional approaches employed to teach fractions (Behr, Harel, Post & Lesh, 1993). Thus, students’ limited understanding might be related to how their teachers understand and interpret fractions — it’s thus related with teachers’ knowledge and practice. Although there is a generalized agreement on teachers’ role on/for students learning, most research on fractions focus on students, leaving aside teachers’ role (and their knowledge on the topic). Thus, teachers’ training has in certain respects been left behind. We still know little about how teachers’ knowledge on fractions influences students’ broader view of mathematics, and its connection and evolution within and along schooling. Aimed at conceptualize ways of improving teachers’ knowledge, training and practices, it’s of fundamental importance to access the areas of knowledge (here conceived as mathematical knowledge for teaching (MKT) (Ball, Thames & Phelps, 2008) in which (prospective) teachers are more deficitaries.

Electro-olfactograms in response to chromatographic fractions of food-related odorants in the Senegalese sole, Solea senegalensis

The Bohr effect, which can be most generally defined as the influence of pH on the oxygen binding affinity of proteins, is a common feature of respiratory pigments, ranging from the haemocyanins of molluscs and crustaceans to the haemoglobins of vertebrates. Its physiological role is generally seen in the facilitation of oxygen release from respiratory pigments during tissue acidosis. The magnitude of the effect can be influenced by a multitude of factors such as temperature, carbon dioxide, chloride ions, organic phosphates and the investigated pH range. Here we present data on the maximal alkaline Bohr effect in haemoglobins from a large number of species covering all vertebrate classes, obtained at physiological temperatures in the presence of 100 mM chloride ions and the absence of carbon dioxide and organic phosphates.

Optimal approximation of fractional derivatives through discrete-time fractions using genetic algorithms

This study addresses the optimization of rational fraction approximations for the discrete-time calculation of fractional derivatives. The article starts by analyzing the standard techniques based on Taylor series and Padé expansions. In a second phase the paper re-evaluates the problem in an optimization perspective by tacking advantage of the flexibility of the genetic algorithms.

In Vitro Ketamine CYP3A Mediated Metabolism Study using Mammalian Liver S9 Fractions, cDNA Expressed Enzymes and Liquid Chromatography Tandem Mass Spectrometry

Ketamine is widely used in medicine in combination with several benzodiazepines including midazolam. The objectives of this study were to develop a novel HPLC-MS/SRM method capable of quantifying ketamine and norketamine using an isotopic dilution strategy in biological matrices and study the formation of norketamine, the principal metabolite of ketamine with and without the presence of midazolam, a well-known CYP3A substrate. The chromatographic separation was achieved using a Thermo Betasil Phenyl 100 x 2 mm column combined with an isocratic mobile phase composed of acetonitrile, methanol, water and formic acid (60:20:20:0.4) at a flow rate of 300 μL/min. The mass spectrometer was operating in selected reaction monitoring mode and the analytical range was set at 0.05–50 μM. The precision (%CV) and accuracy (%NOM) observed were ranging from 3.9–7.8 and 95.9.2–111.1% respectively. The initial rate of formation of norketamine was determined using various ketamine concentration and Km values of 18.4 μM, 13.8 μM and 30.8 μM for rat, dog and human liver S9 fractions were observed respectively. The metabolic stability of ketamine on liver S9 fractions was significantly higher in human (T1/2 = 159.4 min) compared with rat (T1/2 = 12.6 min) and dog (T1/2 = 7.3 min) liver S9 fractions. Moreover significantly lower IC50 and Ki values observed in human compared with rat and dog liver S9 fractions. Experiments with cDNA expressed CYP3A enzymes showed the formation of norketamine is mediated by CYP3A but results suggest an important contribution from others isoenzymes, most likely CYP2C particularly in rat.