Effects of dietary lipid source on growth, digestibility and tissue fatty acid composition of Heterobranchus longifilis fingerlings

One of the major problems facing aquaculture is the inadequate supply of fish oil mostly used for fish feed manufacturing. The continued growth in aquaculture production cannot depend on this finite feed resources, therefore, it is imperative that cheap and readily available substitutes that do not compromise fish growth and fillet quality be found. To achieve this, a 12-week feeding trial with Heterobranchus longifilis fed diets differing in lipid source was conducted. Diets were supplemented with 6% lipid as fish oil, soybean oil, palm oil, coconut oil, groundnut oil and melon seed oil. Triplicate groups of 20 H. longifilis were fed the experimental diets two times a day to apparent satiation, over 84 days. Growth, digestibility, and muscle fatty acid profile were measured to assess diet effects. At the end of the study, survival, feed intake and hepatosomatic index were similar for fish fed experimental diets. However, weight gain, SGR and FCR of fish fed soybean oil-based diet was significantly reduced. Apparent nutrient digestibility coefficients were significantly lower in fish fed soybean, coconut and groundnut oil-based diets. Fillet and hepatic fatty acid compositions differed and reflected the fatty acid compositions of the diets. Docosahexaenoic acid (22:6n-3), 20:5n-3 and 20:4n-6 were conserved in vegetable oils-based diets fed fish possibly due to synthesis of HUFA from 18:3n-3 and 18:4n-6. Palm oil diet was the least expensive, and had the best economic conversion ratio. The use of vegetable oils in the diets had positive effect on growth and fillet composition of H. longifilis.

Análisis de la política petrolera venezolana durante el gobierno de Hugo Chávez como factor determinante de la Revolución Bolivariana (período 1999-2012)

Desde 1999, la política petrolera se constituyó como base del proyecto político chavista conocido como la Revolución Bolivariana, e incluso se convirtió en el eje de la participación, polarización y de las relaciones entre los principales actores del oficialismo y de la oposición venezolana.

The challenges facing privatization of infrastructure projects in Libya

Libya with its strategic location and natural resources stands as a crucial link between the Arab world, Europe, and Africa. The people of Libya have an optimistic outlook with regard to the Libyan economy after the suspension of the United Nations sanctions in 1999 that had been imposed on Libya in 1992, as well as the recent emphasis on privatization from the government. Since then, local and foreign investors have been encouraged to take a more prominent role in order to help privatize some of the state run-industries; the attention to privatization is aimed to help Libya’s economic growth and reduce its heavy dependency on oil revenues. Considering the economic situation, Libya is a rich country. However, it needs to modernize, it needs more and better infrastructure, it needs non-oil based financing, furthermore, it needs to develop a financial model for development and investment from the private sector. Although the Libyan government is working on the improvement of the business environment to make it more attractive for foreign investors in a way to move towards privatization, they have ignored some of the challenges that privatization will be facing in Libya. Privatization can not be implemented overnight. They have taken this for granted without careful consideration of its challenges. This paper attempts to investigate and discuss the challenges that need to be taken into account before privatization of infrastructure projects can be introduced in Libya. This paper is based on interviews with senior technical officials in the government.

The effect of vessel diameter on time dependent gas hold-up variations in highly viscous impeller agitated liquids

Time dependent gas hold-up generated in the 0.3 and 0.6 m diameter vessels using high viscosity castor oil and carboxy methyl cellulose (CMC) solution was compared on the basis of impeller speed (N) and gas velocity (V-G). Two types of hold-up were distinguished-the hold-up due to tiny bubbles (epsilon(ft)) and total hold-up (epsilon(f)), which included large and tiny bubbles. It was noted that vessel diameter (i.e. the scale of operation) significantly influences (i) the trends and the values of epsilon(f) and epsilon(ft), and (ii) the values of tau (a constant reflecting the time dependency of hold-up). The results showed that a scale independent correlation for gas hold-up of the form epsilon(f) or epsilon(ft) = A(N or P-G/V)(a) (V-G)(b), where "a" and "b" are positive constants is not appropriate for viscous liquids. This warrants further investigations into the effect of vessel diameter on gas hold-up in impeller agitated high viscosity liquids (mu or mu(a) > 0.4 Pa s). (C) 2003 Elsevier B.V. All rights reserved.

Resonance response of electrorheological fluids in vertical oscillation squeeze flow

The resonance effect of microcrystalline cellulose/castor oil electrorheological (ER) suspensions was studied in a compressed oscillatory squeeze flow under external electric fields. The resonance frequency first increases linearly with increasing external held, and then shift to high-field plateau. The amplitudes of resonance peak increase sharply with the applied fields in the range of 0.17-1.67kV/mm. The phase difference of the reduced displacement relative to the excitation force inverses in the case of resonance. A viscoelasticity model of the ER suspensions, which offers both the equivalent stiffness and the viscous damping, should be responsible for the appearance of resonance. The influence of the electric field on the resonance frequency and the resonance hump is consistent qualitatively with the interpretation of our proposed model. Storage modulus G' was presented for the purpose of investigating this influence.

Structural Investigation of MFe(2)O(4) (M = Fe, Co) Magnetic Fluids

Ferrites of the type M(II)Fe(2)O(4) (M = Fe and Co) have been prepared by the traditional coprecipitation method. These ferrites were modified by the adsorption of fatty acids derived from soybean and castor oil and were then dispersed in cyclohexane, providing very stable magnetic fluids, readily usable in nonpolar media. The structural properties of the ferrites and modified ferrites as well as the magnetic fluids were characterized by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), DRIFTS (diffusion reflectance infrared Fourier transform spectroscopy), FTMR (Fourier transform near-infrared), UV-vis, normal Raman spectroscopy, and surface-enhanced Raman scattering (SERS). XRD and TEM analysis have shown that the magnetic nanoparticles (nonmodified and modified) present diameters in the range of 10-15 nm. DRIFTS measurements have shown that the carboxylate groups of soybean and castor oil fatty acids adsorb on the ferrite surface, forming three different structures: a bridging bidentate, a bridging monodentate, and a bidentate chelate structure. The FTIR and Raman spectra of nonmodified Fe(3)O(4) and CoFe(2)O(4) nanoparticles have shown that the number of observed phonons is not compatible with the expected O(h)(7) symmetry, since IR-only active phonons were observed. in the Raman spectra and vice versa. SERS measurements of a CoFe(2)O(4) thin film on a SERS-active gold electrode at different applied potentials made possible the assignment of the signals near 550 and 630 cm(-1) to Co-O motions and the signals near 470 and 680 cm(-1) to Fe-O motions.

Finishing diets stimulate compensatory growth: results of a study on Murray cod, Maccullochella peelii peelii

The effective implementation of a finishing strategy (wash-out) following a grow-out phase on a vegetable oil-based diet requires a period of several weeks. However, fish performance during this final stage has received little attention. As such, in the present study the growth performance during both, the initial grow-out and the final wash-out phases, were evaluated in Murray cod (Maccullochella peelii peelii). Prior to finishing on a fish oil-based diet, fish were fed one of three diets that differed in the lipid source: fish oil, a low polyunsaturated fatty acid (PUFA) vegetable oil mix, and a high PUFA vegetable oil mix. At the end of the grow-out period the fatty acid composition of Murray cod fillets were reflective of the respective diets; whilst, during the finishing period, those differences decreased in degree and occurrence. The restoration of original fatty acid make up was more rapid in fish previously fed with the low PUFA vegetable oil diet. During the final wash-out period, fish previously fed the vegetable oil-based diets grew significantly (P < 0.05) faster (1.45 ± 0.03 and 1.43 ± 0.05, specific growth rate, % day−1) than fish continuously fed with the fish oil-based diet (1.24 ± 0.04). This study suggests that the depauperated levels of highly unsaturated fatty acids in fish previously fed vegetable oil-based diets can positively stimulate lipid metabolism and general fish metabolism, consequently promoting a growth enhancement in fish when reverted to a fish oil-based diet. This effect could be termed 'lipo-compensatory growth'.

Tribology of lubricated nitrocarburised and titanium carbonitride surfaces

In the current work, two different coatings, nitrocarburised (CN) and titanium carbonitride (TiCN) on M2 grade high speed tool steel, were prepared by commercial diffusion and physical vapour deposition (PVD) techniques, respectively. Properties of the coating were characterised using a variety of techniques such as Glow-Discharge Optical Emission Spectrometry (GD-OES) and Scanning Electron Microscopy (SEM). Three non-commercial, oil-based lubricants with simplified formulations were used for this study. A tribological test was developed in which two nominally geometrically-identical crossed cylinders slide over each other under selected test conditions. This test was used to evaluate the effectiveness of a pre-applied lubricant film and a surface coating for various conditions of sliding wear. Engineered surface coatings can significantly improve wear resistance of the tool surface but their sliding wear performances strongly depend on the type of coating and lubricant combination used. These coating-lubricant interactions can also have a very strong effect on the useful life of the lubricant in a tribological system. Better performance of lubricants during the sliding wear testing was achieved hen used with the nitrocarburised (CN) coating. To understand the nature of the interactions and their possible effects on the coating-lubricant system, several surface analysis techniques were used. The molecular level investigation of Fourier Transform Infrared Spectroscopy (FTIR) revealed that oxidative degradation occurred in all used oil-based lubricants during the sliding wear test but the degradation behaviour of oil-based lubricants varied with the coating-lubricant system and the wear conditions. The main differences in the carbonyl oxidation region of the FTIR spectra (1900-1600 cm-1) between different coating-lubricant systems may relate to the effective lifetime of the lubricant during the sliding wear test. Secondary Ion Mass Spectrometry (SIMS) depth profiling shows that the CN coating has the highest lubricant absorbability among the tested tool surfaces. Diffusion of chlorine (C1), hydrogen (H) and oxygen (O) into the surface of subsurface of the tool suggested that strong interactions occurred between lubricant and tool surface during the sliding wear test. The possible effects of the interactions on the performance of whole tribological system are also discussed. The study of Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) indicated that the envelope of hydrocarbons (CmHn) of oil lubricant in the positive TOF-SIMS spectra shifted to lower mass fragment after the sliding wear testing due to the breakage of long-chain hydrocarbons to short-chain ones during the degradation of lubricant. The shift of the mass fragment range of the hydrocarbon (CmHn) envelope caries with the type of both tool surface and lubricant, again confirming that variation in the performance of the tool-lubricant system relates to the changes in surface chemistry due to tribochemical interactions at the tool-lubricant interface under sliding wear conditions. The sliding wear conditions resulted in changes not only in topography of the tool surface due to mechanical interactions, as outlined in Chapter 5, but also in surface chemistry due to tribochemical interactions, as discussed in Chapters 6 and 7.

Determination of anabolic steroids by differential pulse polarography

Determination of anabolic steroids often requires the use of elaborate techniques such as gas chromatography - mass spectrometry (GC-MS), gas liquid chromatography (GLC) and more recently high performance liquid chromatography (HPLC). Most of these methods employ derivatisation techniques prior to detection which makes them tedious and relatively time consuming. Other methods demand a great deal of skill. A simple and rapid analytical method, based on differential pulse polarography at a dropping mercury electrode has been developed for the determination of various anabolic steroids in a range of commercially available pharmaceutical preparations. Detailed investigation of the electrochemical behaviour of these steroids was made in order to elucidate the electrode processes involved, in addition to optimising the method. Several other analytical methods such as GC-MS, NMR, ultraviolet (UV), infrared (IR) spectroscopy were also used to confirm the products of the chemical and electrochemical reactions. Possible reactions are suggested. Various extraction procedures were examined for separation of selected steroids from the oil-based or pill matrix and their suitability for polarographic determination is discussed.

Sesamin modulation of lipid class and fatty acid profile in early juvenile teleost, Lates calcarifer, fed different dietary oils

Sesamin, a major sesame seed lignan, has diverse biological functions including the modulation of molecular actions in lipid metabolic pathways and reducing cholesterol levels. Vertebrates have different capacities to biosynthesize long-chain PUFA from dietary precursors and sesamin can enhance the biosynthesis of ALA to EPA and DHA in marine teleost. Early juvenile barramundi, Lates calcarifer, were fed for two weeks on diets rich in ALA or SDA derived from linseed or Echium plantagineum, respectively. Both diets contained phytosterols and less cholesterol compared with a standard fish oil-based diet. The growth rates were reduced in the animals receiving sesamin regardless of the dietary oil. However, the relative levels of n-3 LC-PUFA in total lipid, but not the phospholipid, increased in the whole body by up to 25% in animals fed on sesamin with ALA or SDA. Sesamin reduced the relative levels of triacylglycerols and increased polar lipid, and did not affect the relative composition of phospholipid subclasses or sterols. Sesamin is a potent modulator for LC-PUFA biosynthesis in animals, but probably will have more effective impact at advanced ages. By modulating certain lipid metabolic pathways, sesamin has probably disrupted the body growth and development of organs and tissues in early juvenile barramundi.

Lipidomic profiling of chylomicron triacylglycerols in response to high fat meals

Using lipidomic methodologies the impact that meal lipid composition and metabolic syndrome (MetS) exerts on the postprandial chylomicron triacylglycerol (TAG) response was examined. Males (9 control; 11 MetS) participated in a randomised crossover trial ingesting two high fat breakfast meals composed of either dairy-based foods or vegetable oil-based foods. The postprandial lipidomic molecular composition of the TAG in the chylomicron-rich (CM) fraction was analysed with tandem mass spectrometry coupled with liquid chromatography to profile CM TAG species and targeted TAG regioisomers. Postprandial CM TAG concentrations were significantly lower after the dairy-based foods compared with the vegetable oil-based foods for both control and MetS subjects. The CM TAG response to the ingested meals involved both significant and differential depletion of TAG species containing shorter-and medium-chain fatty acids (FA) and enrichment of TAG molecular species containing C16 and C18 saturated, monounsaturated and diunsaturated FA. Furthermore, there were significant changes in the TAG species between the food TAG and CM TAG and between the 3- and 5-h postprandial samples for the CM TAG regioisomers. Unexpectedly, the postprandial CM TAG concentration and CM TAG lipidomic responses did not differ between the control and MetS subjects. Lipidomic analysing of CM TAG molecular species revealed dynamic changes in the molecular species of CM TAG during the postprandial phase suggesting either preferential CM TAG species formation and/or clearance.

Síntese e impregnação de peneiras moleculares Fe MCM-41 derivada de sílica da casca do arroz

The mesoporous molecular sieves of the MCM-41 and FeMCM-41 type are considered promissory as support for metals used as catalysts in oil-based materials refine processes and as adsorbents for environmental protection proposes. In this work MCM-41 and FeMCM41 were synthesized using rice husk ash - RHA as alternative to the conventional silica source. Hydrothermal synthesis was the method chosen to prepare the materials. Pre-defined synthesis parameters were 100°C for 168 hours, later the precursor was calcinated at 550°C for 2 hours under nitrogen and air flow. The sieves containing different proportions of iron were produced by two routes: introduction of iron salt direct synthesis; and a modification post synthesis consisting in iron salt 1 % and 5% impregnation in the material followed by thermal decomposition. The molecular sieves were characterized by X ray diffraction XRD, Fourier transform infrared spectroscopy FT-IR, X ray fluorescence spectroscopy XFR, scanning electronic microscopy SEM, specific surface area using the BET method, Termogravimetry TG. The kinetic model of Flynn Wall was used with the aim of determining the apparent activation energy of the surfactant remove (CTMABr) in the MCM- 41 porous. The analysis made possible the morphology characterization, identifying the presence of hexagonal structure typical for mesoporous materials, as well as observation of the MCM41 and iron of characteristic bands.

Aplicação de termogravimetria acoplada à espectrometria de massas para caracterização de petróleo e determinação da curva de evolução de gás sulfídrico

With the new discoveries of oil and gas, the exploration of fields in various geological basins, imports of other oils and the development of alternative fuels, more and more research labs have evaluated and characterized new types of petroleum and derivatives. Therefore the investment in new techniques and equipment in the samples analysis to determine their physical and chemical properties, their composition, possible contaminants, especification of products, among others, have multiplied in last years, so development of techniques for rapid and efficient characterization is extremely important for a better economic recovery of oil. Based on this context, this work has two main objectives. The first one is to characterize the oil by thermogravimetry coupled with mass spectrometry (TG-MS), and correlate these results with from other types of characterizations data previously informed. The second is to use the technique to develop a methodology to obtain the curve of evaluation of hydrogen sulfide gas in oil. Thus, four samples were analyzed by TG-MS, and X-ray fluorescence spectrometry (XRF). TG results can be used to indicate the nature of oil, its tendency in coke formation, temperatures of distillation and cracking, and other features. It was observed in MS evaluations the behavior of oil main compounds with temperature, the points where the volatilized certain fractions and the evaluation gas analysis of sulfide hydrogen that is compared with the evaluation curve obtained by Petrobras with another methodology

Desenvolvimento de metodologias analíticas alternativas por cromatografia gasosa para análise de biodiesel

Since the beginning of the National Program for Production and Use of Biodiesel in Brazil, in 2004, different raw materials were evaluated for biodiesel production, trying to combine the agricultural diversity of the country to the desire to reduce production coasts. To determine the chemical composition of biodiesel produced from common vegetables oils, international methods have been used widely in Brazil. However, for analyzing biodiesel samples produced from some alternative raw materials analytical problems have been detected. That was the case of biodiesel from castor oil. Due the need to overcome these problems, new methodologies were developed using different chromatographic columns, standards and quantitative methods. The priority was simplifying the equipment configuration, realizing faster analyses, reducing the costs and facilitating the routine of biodiesel research and production laboratories. For quantifying free glycerin, the ethylene glycol was used in instead of 1,2,4-butanetriol, without loss of quality results. The ethylene glycol is a cheaper and easier standard. For methanol analyses the headspace was not used and the cost of the equipment used was lower. A detailed determination of the esters helped the deeper knowledge of the biodiesel composition. The report of the experiments and conclusions of the research that resulted in the development of alternative methods for quality control of the composition of the biodiesel produced in Brazil, a country with considerable variability of species in agriculture, are the goals of this thesis and are reported in the following pages

Análise macroscópica e histológica do emprego da poliuretana derivada do óleo de mamona (Ricinus communis) aplicada na tíbia de cães em fase de crescimento

OBJETIVO: Estudar o efeito da poliuretana de mamona aplicada ao osso de cães em crescimento. MÉTODOS: Foram utilizados 12 cães subdivididos aleatoriamente em 3 grupos, os quais receberam o implante de mamona na face medial proximal da tíbia, com análise macroscópica e histopatológica aos 30 (GIII), 60 (GII) e 90 (GI) dias. RESULTADOS: A poliuretana foi recoberta por uma cápsula conjuntiva fibrosa, não ocorrendo proliferação óssea ao seu redor. CONCLUSÃO: A poliuretana é biocompatível, comportando-se como espaçador biológico em cães. Nesta espécie não ocorre a osteointegração.