43 resultados para synthetic esters

em Deakin Research Online - Australia


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A new biocompatible ionic liquid P1444DPP (IL1) was investigated as an antiwear additive and compared against Amine Phosphate (AP), one of the commonly used conventional antiwear additives in various biodegradable base stocks. In general, such base stocks (vegetable oil and synthetic esters) are being used for preparing biodegradable industrial lubricants. To further check its efficacy, the results were also compared with one of the ionic liquid P66614DPP (IL2) which has better performance as a lubricant, but is less biocompatible. IL1 showed excellent antiwear performance on pin-on-disc tribometer, when blended in biodegradable base stocks. The steel balls after the pin-on-disc test were analyzed using SEM-EDS technique. The oxidation stability of IL1 was studied by Pressure Differential Scanning Calorimeter (PDSC) and compared with the behavior of AP after incorporating optimized dosage of antioxidant additives in the biodegradable base stock.

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One of the less desirable aftermaths of the so-called "Media Wars" - the intellectual debate over the role of cultural studies in the study of journalism - was reinforcement for some of the notion of fortress journalism: a Windschuttlian purist version of the Empire. This paper uses the alleged confrontation between the forces of that Empire (that is, proponents of pure journalism) and the forces of the Dark (that is, critics from a cultural studies tradition) as a means of examining the teaching of journalism in universities. The paper questions how the discipline of journalism should interface with others within the academy and asks what notion of journalism underpins our pedagogy and our epistemology. It is argued that it is time to discard an outdated craft model with its associations of authenticity and replace it with a model of synthetic professionalism.

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Juvenile Cherax destructor (commonly called the yabby) (mean weight 48.3 mg) were cultured intensively (stocking density 360/m2) under controlled conditions for 48 days. The animals were provided with a combination of food (high protein pellets and/or natural feed organisms attached to a conditioned synthetic substrate) and refuge. Fastest growth and highest yield was recorded when both pellets and the conditioned synthetic material were provided. Although the yabbies sheltered in the synthetic substrate, it did not increase survival. Juvenile yabbies (< 200 mg) were able to graze on small organisms attached to the synthetic material but this ability appeared to decline as the yabbies grew to a larger size. The use of artificial substrates in the intensive nursery phase production of juvenile freshwater crayfish is discussed.

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Heat generation in fabrics coated with the conductive polymer polypyrrole was investigated. The PET fabrics were coated by chemical synthesis using four different oxidizing agent–dopant combinations. The samples from the four different dopant systems all show an increase in temperature when a fixed voltage is applied to the fabric. The antraquinone-2-sulfonic acid (AQSA) sodium salt doped polypyrrole coating was the most effective in heat generation whereas the sodium perchlorate dopant system was the least effective. The power density per unit area achieved in polypyrrole coated polyester–Lycra® fabric with 0.027 mol/l of AQSA acting as dopant was 430 W/m2. The power density per unit area achieved for the sodium perchlorate system, using the same synthesis conditions, was 55 W/m2.


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This study evaluated the production of fatty acid ethyl esters from fish oil using ultrasonic energy and alkaline catalysts dissolved in ethanol. The feasibility of fatty acid ethyl ester production was determined using an ultrasonic bath and probe, and between 0.5 and 1% KOH (added to the fish oil). Furthermore, factors such as ultrasonic device (bath and probe), catalyst (KOH and C2H5ONa), temperature (20 and 60 °C), and duration of exposure (10–90 min) were assessed. Sodium ethoxide was found to be a more efficient catalyst than KOH when transesterifying fish oil. Ultrasonic energy applied for greater than 30 min at 60 °C using 0.8% of C2H5ONa as a catalyst transesterified over 98% fish oil triglycerides to fatty acid ethyl esters. It is reasonable to conclude that the yield of fatty acid ethyl esters produced by applying ultrasonic energy to fish oil is related to the sonication time. Due to increases in the surface area contact between the reactants and the catalyst, ultrasonic energy has the potential to reduce the production time required by a conventional large-scale commercial transesterification method that uses agitation as a way of mixing.

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Several sets of model-based estimates (synthetic estimates) of the prevalence of risk factors for coronary heart disease for small areas in England have been developed. These have been used in policy documents to indicate which areas are in need of intervention. In general, these models have not been subjected to validity assessment. This paper describes a validity assessment of 16 sets of synthetic estimates, by comparison of the models with national, regional and local survey-based estimates, and local mortality rate estimates. Model-based estimates of the prevalence of smoking, low fruit and vegetable consumption, obesity, hypertension and raised cholesterol are found to be valid.

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Background: The utility of fatty acids (FAs) as biomarkers of total fat intake is unknown.

Objective: We compared FA changes in red cells (RCs), plasma phospholipids (PLs), and cholesterol esters (CEs) in response to a low-fat diet (LFD) and a moderate-fat diet (MFD) and assessed whether individual or combination of FAs predict LFD.

Design: Postmenopausal women (n = 66) were randomly assigned to receive an LFD (17% of energy from fat) or an MFD (34% of energy from fat) for 6 wk. All foods were provided. FAs in diets and blood were determined by gas-liquid chromatography. FA changes between baseline and end of study were compared across diets by using t tests. FA predictors of an LFD were selected by logistic regression.

Results: Many FAs in RCs, PLs, and CEs responded differently to the 2 diets. Changes from baseline with an LFD for palmitic acid (16:0) (3–11% increase), behenic (22:0) and lignoceric (24:0) acids (3–20% decrease, in RCs and PLs only), cis-monounsaturated FA (MUFA) (25–35% increase), linoleic acid (18:2n–6) (11–13% decrease), trans octadecanoic acids (trans 18:1) (7–20% decrease), and n–6 highly unsaturated FA (HUFA) (2–8% increase) were significantly different from changes with an MFD. Individually, 18:2n–6 and trans 18:1 were strong predictors of an LFD [receiver operating characteristic (ROC) curves: 0.92–0.80). A logistic regression model with trans 18:1, 18:2n–6, and vaccenic acid (18:1n–7) predicted an LFD with high specificity and sensitivity (ROC curves: 0.99).

Conclusions: Saturated FA, cisMUFA, n–6 HUFA, and exogenous FAs greatly differed in their response to the LFD and MFD. Parallel responses were observed in RCs, PLs, and CEs. A model with a combination of FAs almost perfectly differentiated the consumption of 34% fat from that of 17% fat.

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The oxidation of substituted phenols with phenyliodonium diacetate in methanol was found to afford 2,4-cyclohexadienones, 2,5-cyclohexadienones or mixtures of isomers depending on the substrate being oxidized. A reaction mechanism was proposed for this oxidation which involved an intermediate aryloxenium ion. A strong correlation was observed between the experimentally determined product ratios and the results predicted by calculation of the LUMO coefficients of the proposed intermediates, Annulation of these cyclohexadienones with the anion derived from cyanophthalide afforded substituted anthraquinones in high yields. The chemistry relating to the annulation of Michael acceptors with phthalide anions was comprehensively reviewed. A mild selective method for the oxidation of hydroquinones to quinones using dibenzoyl peroxide and base is presented. A general synthetic approach to C-glycosylanthraquinones was presented, based on the annulation of a C-glycosylcyclohexadienone with the anion derived from cyanophthalide, A suitable precursor to a C-glycosylcyclohexadienone, 2-(2’,3’,4’,6’-tetra-0-acetyl-|3-D-glucopyranosyl)benzyloxybenzene, was prepared via the reaction of benzoylbromoglucose with 2-benzyloxyphenylmagnesium bromide, A group of molecules were prepared by a Marschalk reaction between /ewcoquinizarin and aldehydo-sugsrs. These compounds are potential bioreductive alkylating agents in which molecular simplicity can be achieved without overly sacrificing DNA binding ability.

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