bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational estimation of the composition of fat/oil mixtures containing interesterifications from gas and liquid chromatography data
Authors: van Vliet Martin H. , van Kempen Geert M. P. , Reinders Marcel J. T. , de Ridder Dick
Published: November 2006

A mathematical framework is introduced that relates analytical data to the composition of fat and oil mixtures. Within this framework, the noise characteristics of four common analytical techniques [FAME, FAME2‐pos, CN (carbon number), and AgLC] were investigated and modeled by both additive and multiplicative noise terms. The fat blend recognition (FBR) performance was investigated under these two types of noise, both qualitatively and quantitatively. Furthermore, an extension is proposed that makes it possible to detect interesterifications of unknown mixtures, which was impossible before. The proposed procedure is divided into a qualitative estimation stage, which is focused on identifying the raw materials (RM), followed by a quantitative estimation stage, which is focused on quantifying the levels of the RM identified. We compared two qualitative strategies and four quantitative methods for their ability to correctly estimate simulated mixtures under the noise characteristics determined. The comparison of methods was extended to actual mixtures, revealing promising results. Our analysis presents multiple directions for further adulteration and FBR studies.
Sterol fractions in hazelnut and virgin olive oils and 4,4′‐dimethylsterols as possible markers for detection of adulteration of virgin olive oil
Authors: Damirchi Sodeif Azadmard , Savage Geoffrey P. , Dutta Paresh C.
Published: November 2006

Reports on the methylsterol fractions of hazelnut oils are scarce. The objectives of this study were to characterize methylsterols in hazelnut and virgin olive oils and to study the possibility of detection of adulteration of virgin olive oils. In hazelnut oils, 4‐desmethylsterols were present in higher proportions (86 to 91%) than in virgin olive oils where this fraction was ca. 50% of the total sterol. In the 4‐monomethylsterol fraction, citrostadienol was the major component in both kinds of oils followed by cycloeucalenol and obtusifoliol in virgin olive oils, and obtusifoliol in hazelnut oils. 24‐Methylenecycloartanol was predominant in both kinds of oils in the 4,4′‐dimethylsterols. For the first time, δ‐amyrin was tentatively identified by comparing published mass spectral data in the analyzed samples of both kinds of oils. An unknown compound X (containing a lupane skeleton) and lupeol were detected only in the 4,4′‐dimethylsterols fraction of hazelnut oils at a level of 2–8 and 6–10%, respectively. GC‐MS analysis showed that adulteration of virgin olive oil by hazelnut oil could be detected at a level less than 4% by using these two compounds as possible potential markers.
Safety evaluation of ambrette (Abelmoschus moschatus linn) seed oil
Authors: Rao Y. R. , Jena K. S. , Sahoo D. , Rout P. K. , Ali Shakir
Published: November 2006

The seeds of ambrette (Abelmoschus moschatus Linn), after selective extraction of fragrance from the seed coat, are flaked and extracted with hexane to obtain a fatty oil. The FA composition and iodine value of the oil indicate it possesses saturated, monounsaturated, and polyunsaturated FA in ratios close to the recommendations of the United Nations World Health Organization; these characteristics make it suitable as an edible oil. Acute oral toxicity and safety evaluation in a 13‐wk feeding trial on albino rats showed the oil is comparable to groundnut oil in all the parameters and is suitable for edible use.
High‐throughput determination of oil content in corn kernels using nuclear magnetic resonance imaging
Authors: Kotyk John J. , Pagel Marty D. , Deppermann Kevin L. , Colletti Ronald F. , Hoffman Norman G. , Yannakakis Elias J. , Das Pradip K. , Ackerman Joseph J. H.
Published: November 2006

A new high‐throughput method for measuring oil content in intact, single corn kernels is demonstrated using nuclear magnetic resonance imaging (MRI) methods. This nondestructive technique enables the evaluation of relative oil content in up to 2,592 corn kernels in less than 40 min using a 1.5 T clinical MRI scanner. Custom software was developed to process and analyze 3‐D magnetic resonance (MR) image data rapidly. The precision and accuracy of the MR method for measuring oil content are discussed. The precision of the MRI results is shown to be dependent on MR scanner noise. The MRI results show very good relative accuracy compared with low‐field NMR, NIR transmission, and accelerated solvent extraction measurements. Minor differences between the MRI and low‐field NMR experimental protocols were shown to be inconsequential to the oil content measurement. Extending the MRI method to the analysis of other oilseeds and/or the use of other magnetic field strengths is discussed, as is a comparison of this MRI method relative to other high‐throughput magnetic resonance screening techniques.
Characterization of laurel fruit oil from Madeira Island, Portugal
Authors: Castilho Paula C. , Costa Maria do Céu , Rodrigues Ana , Partidário Ana
Published: November 2006

The fixed oil extracted from Laurus spp. fruit from Madeira Island, Portugal, is used in local traditional medicine for a wide variety of health complaints. Physical properties, density and refractive index, as well as the TAG FA composition, sterols, and waxes were determined. The oil was found to have an unusually high content of volatiles (ca. 10%), with trans‐ocimene and germacrene D predominating. Oleic (30%) and linoleic (20%) acids were the main unsaturated FA, whereas lauric (18%) and palmitic (up to 22.5%) acids were the main saturated FA in the neutral lipid fraction. The oil had a sterol content on the same order as olive oil, with β‐sitosterol (84%) predominating. Two sesquiterpene lactones, dehydrocostuslactone and costunolide, accounted for 5% of the overall composition. Madeira laurel oil is not currently used as an edible oil because of its very strong flavor. Its claimed medicinal properties have not yet been validated, and this is the first report on the characterization of the commercial product.
Evaluation of oxidative stability of canola oils by headspace analysis
Authors: Richards Amy , Wijesundera Chakra , Salisbury Phil
Published: November 2006

Lipid oxidation is a major factor affecting flavor quality and shelf life of vegetable oils. Oxidative stability is therefore an important criterion by which oils are judged for usefulness in various food applications. In this study a method based on headspace analysis was developed to evaluate relative oxidative stability of canola oils. The method does not require the use of chemicals, involves minimal sample preparation, and can be performed on a relatively small sample size in comparison with traditional wet chemical methods. Canola oils freshly extracted in the laboratory from different seed samples were subjected to accelerated oxidation and analyzed for PV by standard methods and headspace volatiles by solid phase microextraction/GC‐MS. Forward stepwise regression analysis of the data revealed a relationship between PV and headspace concentration of the volatile lipid oxidation products hexanal and trans,trans‐2,4‐heptadienal. The PV calculated using this formula correlated (R2=0.73) with those measured by conventional methods.
Lipase‐assisted acidolysis of high‐laurate canola oil with eicosapentaenoic acid
Authors: Hamam Fayez , Daun James , Shahidi Fereidoon
Published: November 2006

The production of structured lipids via acidolysis of high‐laurate canola oil (Laurical 15) with EPA in hexane was carried out using lipase from Pseudomonas sp. The optimal reaction conditions used 4% lipase, at a mole ratio of oil to EPA of 1∶3 at 45°C over 36 h. The positional distribution of FA on the glycerol backbone of unmodified oil indicated that lauric acid was mainly located at the sn‐1,3 positions. Stereospecific analysis of the oil modified with EPA showed that lauric acid remained mostly esterified to the sn‐1,3 positions of the TAG molecules and that EPA was also primarily in the sn‐1,3 positions of the TAG molecules. Thus, the resultant structured lipids may have optimal value for use in applications where quick energy release and EPA supplementation are required.
Lipase‐catalyzed esterification of lactic acid with straight‐chain alcohols
Authors: Roenne Torben H. , Xu Xuebing , Tan Tianwei
Published: November 2006

Enzymatic synthesis of esters of lactic acid and straight‐chain alcohols with different chain lengths (C6–C18) were investigated in batch reactions with hexadecanol (C16) as the model alcohol. Cyclohexane was the best solvent for higher ester yields, and the best biocatalyst was the immobilized Candida antarctica lipase B (Novozym 435) as well as the textile‐immobilized Candida sp. lipase. A method was established to obtain ester yields in the range of 71 to 82% for the different alcohols, and the most favorable conditions for the esterification reaction using Novozym 435 were an equimolar ratio of lactic acid to alcohol, each at a concentration of 120 mM each; a 50°C reaction temperature; 190 rpm shaking speed; and the addition of 100 mg molecular sieves (4 Å) for drying. The ester yield increased with increasing lipase load, and a yield of 79.2% could be obtained after 24 h of reaction at 20 wt% of Novozym 435. The immobilized Candida sp. lipase prepared in the laboratory also could be used to produce esters of lactic acid and straight‐chain alcohols, but it had a much lower activity than Novozym 435 with a temperature optimum of 40°C.
Sepiolite: An effective bleaching adsorbent for the physical refining of degummed rapeseed oil
Authors: Sabah Eyüp , Çelik Mehmet Sabri
Published: November 2006

The efficiency of Turkish sepiolite in bleaching degummed rapeseed oil has been investigated. Experimental results indicate that the bleaching efficiency is more dependent on the ratio of sepiolite to oil than on operating parameters such as contact time and temperature. An increase in the sepiolite dosage reduces the color bodies of the rapeseed oil. Its effect on oxidation state, however, is complex and related to both primary and secondary oxidation products. The removal of impurities such as chlorophyll a, β‐carotene, and phosphorus increases with increasing sepiolite dosage and reaches a maxumum at 1.5% sepiolite addition and 100°C bleaching temperature. Chlorophyll a, β‐carotene, and phosphorus adsorptions can be described by a mechanism involving surface are and porosity of acid‐activated sepiolite as key variables. The sorption is also independent of the polarity of the adsorbate molecules. Direct comparison of activated sepiolite with the commercial bleaching earth Tonsil 210 FF shows that in some respects sepiolite offers significant advantages.
Supercritical fluid extraction to determine the oil content in copra and extracted meal
Authors: Asis Celestino , Baroy Ruther , Bendijo Socorro , Hansen Steven L. , Nacion Vivien , Tolimao Jimmy
Published: November 2006

Supercritical fluid extraction (SFE) was used as a primary method to determine the oil content of copra and its meal. Determination of the oil content of copra takes 9 h, and for meal 6 h are necessary with Soxhlet extraction, whereas SFE determined oil contents in about 10 min. The extremely high oil content of copra makes grinding difficult, as the sample becomes very gummy and it is difficult to remove the entire sample from the grinder. Adding diatomaceous earth to the sample before grinding eliminated the difficulties of cleaning the grinder and also enabled very fast SFE extractions. The variances for Soxhlet and SFE were not significantly different from each other (P>0.10) in both copra and meal oil contents. The 95% confidence interval around the mean differences (SFE‐Soxhlet) was (−0.35, 0.90) and (0.08, 0.26) and for copra and meal, respectively. Although the SFE meal oil content (9.81%) was significantly higher than the Soxhlet meal oil content (9.64%), the size of the average difference (0.17%) was relatively small. This small difference was considered acceptable owing to the ability to use SFE in real‐time process control. Therefore, SFE can be used to determine the oil content in copra and its meal in less than 10 min.
Improvement of biodiesel production based on the application of ultrasound: Monitoring of the procedure by FTIR spectroscopy
Authors: Siatis N. G. , Kimbaris A. C. , Pappas C. S. , Tarantilis P. A. , Polissiou M. G.
Published: November 2006

A novel application of ultrasounds is presented for the improvement of the efficiency of the production of FAME (or biodiesel) from materials not used so far for this purpose, such as seed cakes. The novelty of this work is the introduction of in situ derivatization assisted by ultrasounds (ultrasonically assisted extraction transesterification) for biodiesel production. Thus, the TG contained in solid material are extracted and immediately transesterified in a methanolic solution of 1 M NaOH in an ultrasonic field. The total yield of FAME from seeds that contain TG is greatly increased in most instances. In the seeds use in this work yields were increased from 46 to 85.5% for cotton, 67.2 to 93% for sunflower, and 43.2 to 83.5% for sesame. An FTIR methodology was developed to determine the percentage of FAME in the n‐hexane layer of the reaction and thus, to monitor the reaction process. Overall advantages of the proposed methodology include the elimination of saponification, low reaction time, milder reaction conditions, and higher FAME yields.
Kinetics and quantitative structure‐activity relationships for pseudomonas sp. Lipase‐catalyzed hydrolysis of both monoesters and diesters of ethylene glycol
Authors: Chiou Shyh‐Ying , Cheng Yu‐Ru , Lu Chun‐Ping , Lin Yan‐Fu , Lin Long‐Yau , Lin Gialih
Published: November 2006

The goal of this work is to study kinetics and quantitative structure‐activity relationships for steady states of Pseudomonas sp. lipase‐catalyzed hydrolysis of both diesters and monoesters of ethylene glycol. Based on the steady‐state kinetics of the enzyme‐catalyzed hydrolysis of the diesters of ethylene glycol, the diesters and the monoesters react simultaneously as soon as monoester has started to build up in the reaction medium. In other words, the apparent Km values of the diesters are the Km values of the diesters (KmA) plus the Km values of the monoesters (KmB), and all Vmax values are about the same. Moreover, the pH‐stat titration curve of the enzyme‐catalyzed hydrolysis of the diesters of ethylene glycol is initially hyperbolic, then there is a sharp falloff in the hydrolysis rate. The abrupt stoppage of the reaction (relaxation stage) may be due to the existence of two phases in the reaction medium, that is, the product (ethylene glycol) and the substrates (the diesters of ethylene glycol) are not miscible. Furthermore, quantitative structure‐activity relationships for varied acyl groups of mono‐and diesters of ethylene glycol are studied. The fact that both pKmA and pKmB values are linearly correlated with the hydrophobicity constant (π) but not with the electronic substituent constants (σ*) indicates that the affinity of these substrates for the enzyme depends only on the hydrophobicity of substrates.
Concentration of eicosapentaenoic acid by selective esterification using lipases
Authors: Fajardo A. Ramírez , Cerdán L. Esteban , Medina A. Robles , Martínez M. M. Muñío , Peña E. Hita , Grima E. Molina
Published: November 2006

The aim of this work was to increase the content of EPA in FFA extracts from a commercial oil (43.1% EPA) and from Phaeodactylum tricornutum oil, a single‐cell oil, by selective enzymatic esterification. Initially, the FFA extract was esterified with lauryl alcohol using nine lipases. All the lipases concentrated EPA in the unesterified FFA fraction. The criterion used to choose the best lipase was maximization of the dimensionless effectiveness factor (FAE). This factor grouped the concentration factor (ratio between the EPA concentrations in the FFA fractions before and after esterification) with EPA recovery in the final FFA fraction. Experiments were carried out to correlate FAE and the degree of esterification (ED, percentage of initial FA converted to lauryl esters). Lipase AK from Pseudomonas fluorescens was the most effective for concentrating EPA. Studies, of the optimal temperature, substrate molar ratio, solvent/substrate ratio, and treatment intensity (product of the lipase mass and the reaction time) were also carried out using the lipase. The maximum FAE was obtained when the ED was 60%: EPA concentration was 72%, and recovery was 73%. Finally, this lipase was used to concentrate EPA from a FFA extract from P. tricornutum (23% EPA). The content of EPA in the unesterified FFA fraction increased to 71% at 78% ED (recovery of EPA, 75.5%). Comparison of the results of obtained with the two FFA extracts seemed to indicate that the selectivity of Lipase AK for EPA depended on the content of EPA, with higher contents of EPA in the initial FFA mixture reducing the selectivity for EPA.
Analytical characterization of hemp (Cannabis sativa) seed oil from different agro‐ecological zones of Pakistan
Authors: Anwar Farooq , Latif Sajid , Ashraf Muhammad
Published: November 2006

Cold‐pressed oil content of Cannabis sativa (hemp) seeds from three different agro‐ecological zones of Pakistan ranged from 26.90 to 31.50%. Protein, fiber, ash, and moisture content were found to be 23.00–26.50, 17.00–20.52, 5.00–7.60, and 5.60–8.50%, respectively. Results of some other physical and chemical parameters of the oil were as follows: iodine value, 154.00–165.00; refractive index (40°C), 1.4698–1.4750; density (24°C), 0.9180–0.9270 mg ml−1; saponification value, 184.00–190.00; unsaponifiable matter, 0.70–1.25%; and color (1‐in cell), 0.50–0.80 R+27.00–32.00 Y. The induction period (Rancimat, 20 L h−1, 120°C) of the nondegummed and degummed oils ranged from 1.35 to 1.72 h and from 1.20 to 1.49 h, respectively. Specific extinctions at 232 and 270 nm were 3.50–4.18 and 0.95–1.43, respectively. The hemp oils investigated were found to contain high levels of linoleic acid, 56.50–60.50%, followed by α‐linolenic, oleic, palmitic, stearic, and γ‐linolenic acids: 16.85–20.00, 10.17–14.03, 5.75–8.27, 2.19–2.79, and 0.63–1.65%, respectively. Tocopherols (α, γ, and δ) in the nondegummed oils were found to be 54.02–60.40, 600.00–745.00, 35.00–45.60, respectively, and were reduced to 29.90–50.00, 590.00–640.00, and 30.40–39.50 mg kg−1, respectively, after degumming. The results of the present analytical study, compared with those found in the typical literature on hempseed oils, showed C. sativa indigenous to Pakistan to be a potentially valuable nonconventional oilseed crop of comparable quality.
Tocopherol distribution and molecular species of triacylglycerols in soybean embryonic axes
Authors: Yoshida Hiromi , Tomiyama Yuka , Kanrei Saki , Mizushina Yoshiyuki
Published: November 2006

Soybean embryonic axes were separated from other tissues, i.e., the cotyledons and seed coat. The molecular species and FA distribution of TAG isolated from total lipids in the embryonic axes were analyzed by a combination of argentation‐TLC and GC, and were investigated in relation to their tocopherol distribution, which was determined by HPLC. The dominant components were γ‐tocopherols, with much smaller amounts of α‐, β‐, and δ‐tocopherols. A modified argentation‐TLC procedure, developed to optimize the separation of the complex mixture of total TAG, provided 16 different groups of TAG, based on both the degree of unsaturation and the total acyl‐chain length of FA groups. With a few exceptions, the major TAG components were S2D (6.8–10.3%), SMD (6.9–11.2%), SD2 (7.2–9.8%), SMT (3.2–7.4%), SDT (11.5–19.5%), D3 (3.5–8.3%), MDT (4.5–7.7%), D2T (11.1–20.6%), and DT2 (8.2–15.7%) (where S denotes saturated FA, M denotes monoenes, D denotes dienes, and T denotes trienes). These results indicate that there were significant differences (P<0.05) not only in tocopherol distribution but also in the molecular species of TAG among the four cultivars. Therefore, these tissues should be made available as raw materials for soybean‐germ oil or soy milk, based on the differences in the distributions of tocopherol homologs and the molecular species of TAG within the embryonic axes.
Microstructure and fractal analysis of fat crystal networks
Authors: Tang Dongming , Marangoni Alejandro G.
Published: November 2006

This paper reviews the study of the morphology and physical properties of fat crystal networks. Various microscopical and rheological methods can be used to quantify the microstructure of fats, with the ultimate aim of relating structure to mechanical response. Even though a variety of physical models have been proposed to explain the relationship between the mechanical properties of fats and their microstructure, the fractal scaling model most closely describes the experimentally observed behavior. Mass fractal dimensions determined by microscopy and rheology can be used successfully to quantify the microstructure of fats since fractal dimension values are sensitive to the combined effects of crystal size, morphology, and the spatial distribution of mass within the fat crystal network. Methods used to determine the fractal dimension of a fat crystal network such as box counting, particle counting. Fourier transform, light scattering and oil migration are explained in detail here. The relationship between fractal dimensions determined by microscopy and rheology are discussed in light of the fact that different measures of the fractal dimension describe different microstructural features in a fat crystal network.
The regiospecific position of 18∶1 cis and trans monoenoic fatty acids in milk fat triacylglycerols
Authors: Kallio Heikki , Korkiasaari Kati , Sjövall Olli , Suomela Jukka‐Pekka , Linderborg Kaisa
Published: November 2006

TAG of butterfat were fractionated according to the type and degree of unsaturation into six fractions by silver‐ion HPLC. The fractions containing TAG with either cis‐or trans‐monoenoic FA were collected and fractionated further by reversed‐phase HPLC to obtain fractions containing cis TAG of ACN:DB (acyl carbon number:double bonds) 48∶1, 50∶1, and 52∶1 as well as trans 48∶1, 50∶1, and 52∶1. The FA compositions of these fractions were elucidated by GC. The MW distribution of each fraction was determined by ammonia negative‐ion CI‐MS. Each of the [M‐H]− parent ions was fractionated further by collision‐induced dissociation with argon, which gave information on the location of cis‐and trans‐FA between the primary and secondary positions of TAG. The results suggest that the sn‐positions of the monoenoic cis‐and trans‐FA depend on the two other FA present in the molecule. With 14∶0 FA in the TAG molecule, the 18∶1 FA in the sn‐2 position are mostly present as cis‐isomers. When there is no 14∶0 in the TAG molecule, the trans‐18∶1 isomers seem to be more common in the sn‐2 position. Also when other long‐chain FA are present, the trans‐isomers are more likely to be located in the secondary (sn‐2) position.
Comparison of bio‐ and autocatalytic esterification of oils using mono‐ and diglycerides
Authors: De B. K.
Published: November 2006

The purpose of this study was to investigate enzymatic and autocatalytic esterification of FFA in rice bran oil (RBO), palm oil (PO), and palm kernel oil (PKO), using MG and DG as esterifying agents. The reactions were carried out at low pressure (4–6 mm Hg) either in the absence of any added catalyst at high temperature (210–230°C) or in the presence of Mucor miehei lipase at low temperature (60°C). The reactions were carried out using different concentrations of MG, and the optimal FFA/MG ratio and time were 2∶1 (molar) and 6 h, respectively, in both auto‐ and enzyme‐catalyzed processes. With DG as the esterifying agent in the autocatalytic process, the optimal temperature was 220°C, and the optimal FFA/DG ratio was 1∶1.25. For both MG and DG, the enzymatic process was more effective in reducing FFA and produced more favorable levels of unsaponifiable matter and color in the final product. The PV of the final products were also lower (1.8–2.9 mequiv/kg) by using the enzymatic process. To produce edible‐grade oil, a single deodorization step would be required after enzymatic esterification; whereas, alkali refining, bleaching, and deodorization would be required after autocatalytic treatment.
Formation, structure, and rheological properties of ricinelaidic acid‐vegetable oil organogels
Authors: Wright Amanda J. , Marangoni Alejandro G.
Published: November 2006

Vegetable oil‐based organogels were formed using ricinelaidic acid (12‐hydroxy‐9‐trans‐octadecenoic acid, REA). Gelation kinetics, gel structure, and stability were studied. Gelation occurred with as little as 0.5% (w/w) REA, depending on temperature and oil composition. Phase diagrams were constructed using canola, sesame, and DAG oils. Lower gelation tendencies were correlated with the presence of potential hydrogen‐bonding moieties in the oils. REA concentration had a significant influence on gelation kinetics and gel rheology. At 5°C, the 0.5% canola oil gel behaved like a weak, viscoelastic network composed of entangled strands. Between 1.0 and 5.0% REA, solid‐like, viscoelastic gels were formed. The 24‐hour G′LVR (storage modulus in the linear viscoelastic region) was highly dependent on concentration and less so on temperature. Values for gelation time indicated a change in behavior below 2% REA and above 20°C. Polarized light microscopy revealed that the gels were formed through the interactions of long, thin, and birefringent fibers. Structural analysis using X‐ray diffractometry (XRD) indicated the presence of repeating REA dimers and increasing order with concentration and gel storage time. Increases in gel opacity, birefringence, XRD scattering, and fiber clustering were observed during storage.
Antioxidant activity of rapeseed phenolics and their interactions with tocopherols during lipid oxidation
Authors: Thiyam U. , Stöckmann H. , Schwarz K.
Published: November 2006

Commercial rapeseed press cakes are rich sources of phenolic compounds, namely, sinapic acid derivatives, which can be extracted as free sinapic acid and its bound forms (such as sinapine, the choline ester of sinapic acid). Fractionated rapeseed extracts rich in sinapic acid and sinapine were compared for their capacity to inhibit the formation of lipid oxidation products. Oxidation at 40°C was monitored by the formation of hydroperoxides (indicating primary oxidation products) and propanal (secondary oxidation products). The 70% methanolic extract of rapeseed meal, added as an equivalent of 500 μmol/kg oil (based on sinapic acid equivalent for sinapic acid‐rich extracts or sinapine equivalent for sinapinerich extracts) showed good antioxidative activity compared with the addition of 500 μmol/kg oil sinapic acid. Apart from this, the interaction between a mixture of α‐/γ‐tocopherol and sinapic acid was investigated using response surface methodology for the experimental design. The experiments indicated that the addition of sinapic acid (concentration dependent) caused inhibition of peroxide formation, complementing further lower endogenous tocopherol concentration in oils.
Application of raman spectroscopy to monitor and quantify ethyl esters in soybean oil transesterification
Authors: Ghesti Grace F. , de Macedo Julio L. , Braga Valdeilson S. , de Souza Antonio T. C. P. , Parente Vicente C. I. , Figuerêdo Esdras S. , Resck Inês S. , Dias José A. , Dias Sílvia C. L.
Published: November 2006

Biodiesel (FA esters) has become very attractive as an alternative diesel fuel owing to its environmental benefits. Transesterification is the most usual and important method to make biodiesel from vegetable oils. This article investigates the potential for using Raman spectroscopy to monitor and quantify the transesterification of soybean oil to yield ethyl esters. The differences observed in the Raman spectra of soybean oil after transesterification were a peak at 2932 cm−1 (), the displacement of the vC=O band from 1748 to 1739 cm−1, and the bands at 861 (vR‐C=O and vC‐C) and 372 cm−1 (δCO‐O‐C). Uni‐ and multivariate analysis methods were used to build several analytical curves and then applied in known samples, treated as unknowns, to test their ability to predict concentrations. The best results were achieved by Raman/PLS calibration models (where PLS=partial least squares regression) using an internal normalization standard (v=C‐H band). The correlation coefficient (R2) values so obtained were 0.9985 for calibration and 0.9977 for validation. Univariate regression analysis between biodiesel concentration and the increasing intensity of band or vC=O displacement showed R2 values of 0.9983 and 0.9742, respectively. Although spectroscopic methods are less sensitive than chromatographic ones, the data obtained by spectroscopy can be correlated with other techniques, allowing biodiesel yield and quality to be quickly assessed.
Enzymatic preparation of enantiomerically pure sn‐2,3‐diacylglycerols: A stereoselective ethanolysis approach
Authors: Piyatheerawong Weera , Yamane Tsuneo , Nakano Hideo , Iwasaki Yugo
Published: November 2006

Stereoselective ethanolysis of monoacid TAG by immobilized Rhizomucor miehei lipase (RML) was studied for preparation of optically pure sn‐2,3‐DAG. Trioctanoylglycerol (TO) was used as a model substrate. The enantiomeric purity of the product, sn‐2,3‐dioctanoylglycerol (sn‐2,3‐DO), was very high (percent enantiomeric excess >99%) when an excess of ethanol was used. The result indicated that RML was highly stereoselective toward the sn‐1 position of TO under conditions of excess ethanol. The stereoselectivity of RML depended on the amount of ethanol. The larger the amount of ethanol was, the higher the stereoselectivity became. After optimizing the parameters such as reactant molar ratio, water content, and temperature, (ethanol/TO molar ratio =31∶1 and water content =7.5 wt% of the reactants at 25°C), optically pure sn‐2,3‐DO was obtained at 61.1 mol% in the glyceride fraction in 20 min. The above conditions were further applied for ethanolysis of monoacid TAG with different acyl groups such as tridecanoylglycerol (C10∶0), tridodecanoylglycerol (C12∶0), tritetradecanoylglycerol (C14∶0) and trioctadecenoylglycerol [triolein, (C18∶1)]. The yields and enantiomeric purities of 1,2(2,3)‐DAG were dramatically reduced when TAG with FA longer than decanoic acid were used.
Partial separation of polyunsaturated fatty acid esters from FAMEs mixtures by adsorption on silver nitrate‐impregnated silica gel
Authors: Ghebreyessus Kesete Y. , Schiltz Holly , Angelici Robert J.
Published: November 2006

Mixtures of FAMEs derived from soybean and canola oils were fractionated by contacting their hexane solutions with AgNO3/SiO2 adsorbents. Methyl linolenate (18∶3) adsorbed most strongly, followed by methyl linoleate (18∶2), on the AgNO3/SiO2. Conditions of the extractions (AgNO3 loading, amount of adsorbent, methyl soyate/hexane solution concentration, use of successive extractions, and methods of adsorbent regeneration) were varied. Under optimal conditions, the 7.0% of 18∶3 in methyl soyate could be reduced to 0.1%. The described process is a simple method for separating a FAMEs mixture into a fraction that is depleted in polyunsaturated FAMEs and one that is enriched.
Adherence of Irish general practitioners to European guidelines for acute low back pain: A prospective pilot study
Authors: Fullen Brona M. , Maher Thomas , Bury Gerard , Tynan Aodan , Daly Leslie E. , Hurley Deirdre A.
Published: November 2006

There are no national low back pain (LBP) clinical guidelines in Ireland, and neither the level of adherence of General Practitioners (GPs) to the European guidelines, nor the cost of LBP to the patient and the state, have been investigated.

A prospective pilot study was conducted on 54 consenting patients (18M, 36F: mean age (SD): 40.5 (14.3) years) with a new episode of acute LBP (<3 months) attending one of nine participating GPs. Baseline demographic, LBP classification [i.e. simple back ache (SBA), nerve root pain (NRP), serious spinal pathology (SSP)] and primary care management data were recorded over a three month period. Adherence and costs were estimated based on: medication prescription, referral for investigations, treatment or consultations, and wage replacement costs (time signed off work).

For both SBA and NRP, medication prescriptions were consistent with European guideline recommendations, but not for referral for further treatment (39% of SBA patients were referred on first visit), secondary care (54% of NRP patients were referred on first visit), or discontinuation of work (50% NRP patients on first GP visit). The average total cost (direct and wage replacement) for a single episode of LBP over 12 weeks was €20,531 (20,300–20,762). Direct costs accounted for 43% [€8874.36, (€8643.37–€9105.37)] and wage replacement costs 57% (€11,657).

In conclusion, management of acute LBP in a cohort of GPs in Ireland was not consistent with European clinical guideline recommendations, and warrants higher levels of postgraduate education among GPs, as well as restructuring of primary care services, which should improve patient outcome and reduce costs.
The intrachain disulfide bridge is responsible of the unusual stability properties of novel acylphosphatase from Escherichia coli
Authors: Ramazzotti Matteo , Parrini Claudia , Stefani Massimo , Manao Giampaolo , Degl'Innocenti Donatella
Published: November 2006

Acylphosphatase (AcP) activity in prokaryotes was classically attributed to some aspecific acid phosphatases. We identified an open reading frame for a putative AcP in the b0968 Escherichia coli gene and purified the recombinant enzyme after checking by RT‐PCR that it was indeed expressed. EcoAcP has a predicted typical fold of the AcP family but displays a very low specific activity and a high structural stability differently from its mesophilic and similarly to its hyperthermophilic counterparts. Site directed mutagenesis suggests that, together with other structural features, the intrachain S–S bridge in EcoAcP is involved in a remarkable thermal and chemical stabilization of the protein without affecting its catalytic activity.
PI3‐kinase/Akt‐dependent antiapoptotic signaling by the PDGF α receptor is negatively regulated by Src family kinases
Authors: Vantler Marius , Huntgeburth Michael , Caglayan Evren , ten Freyhaus Henrik , Schnabel Petra , Rosenkranz Stephan
Published: November 2006

Regulation of growth factor dependent cell survival is crucial for development and disease progression. Here, we report a novel function of Src kinases as a negative regulator of platelet‐derived growth factor (PDGF) dependent cell survival. We characterized a series of PDGF α receptor (PDGFRA) mutants, which lack the binding sites for Src, phosphatidylinositol 3′‐kinase (PI3K), SHP‐2 or phospholipase C‐γ. We found that PDGFRA‐dependent cell survival was mainly mediated through activation of PI3K, and was negatively regulated by Src. Characterization of the downstream signaling events revealed that PI3K activates the protein kinase Akt, which in turn phosphorylates and thus inactivates proapoptotic Forkhead transcription factors. Src phosphorylates the ubiquitin‐ligase c‐Cbl, which is required for degradation of the activated receptor. Consequently, overexpression of c‐Cbl prevented PDGFRA‐mediated cell survival, whereas it did not affect this response, when Src was unable to associate with the receptor. This novel function of Src in antiapoptotic signaling introduces Src kinases as an interesting therapeutic target in apoptosis related diseases.
Identification of F‐box proteins that are involved in resistance to methylmercury in Saccharomyces cerevisiae
Authors: Hwang Gi-Wook , Ishida Yosuke , Naganuma Akira
Published: November 2006

We searched for F‐box proteins that might be related to the mechanism that protects Saccharomyces cerevisiae against the toxic effects of methylmercury. We found that overexpression of Hrt3 and of Ylr224w rendered yeast cells resistant to methylmercury. Yeast cells that overexpressed Hrt3 and Ylr224w were barely resistant to methylmercury in the presence of a proteasome inhibitor. Our results suggest the existence of some protein(s) that enhances the toxicity of methylmercury in yeast cells and, also, that overexpression of Hrt3 or Ylr224w can confer resistance to methylmercury by enhancing the polyubiquitination of this protein(s) and its degradation in proteasomes.
Olanzapine as Maintenance Therapy in Patients with Bipolar I Disorder
Authors: Tohen Mauricio , Yen Lin Daniel
Published: November 2006

ABSTRACT

Effective treatments for the prevention of relapse and recurrence of mood episodes in patients with bipolar disorder are essential to reduce the high mortality associated with this condition, and to improve long-term outcomes. While lithium is considered to be effective as a first line maintenance treatment, additional treatment options would provide clinicians with tools to address the needs of individual patients. The efficacy of olanzapine, an atypical antipsychotic, for the prevention of relapse in bipolar disorder has been demonstrated in several randomized controlled double-blind clinical trials, both as monotherapy and in combination with other agents. The data reviewed herein suggest a more robust efficacy of treatment with olanzapine in the prevention of relapse into manic episodes than into depressive episodes. The adverse events observed most frequently in patients treated with olanzapine relative to comparators were related to somnolence (somnolence, fatigue, or hypersomnia) and weight gain (weight gain, or increased appetite). Moreover, a larger proportion of olanzapine-treated patients than comparator-treated patients experienced clinically important weight gain.
Magnitude distribution complexity revealed in seismicity from Greece
Authors: Lasocki Stanislaw , Papadimitriou Eleftheria E.
Published: November 2006

The structure of the magnitude distribution of earthquakes from three different seismotectonically homogeneous areas of Greece has been investigated by means of statistical inference methods. Unlike in previous studies, a nonparametric approach, namely, the smoothed bootstrap test for multimodality applied in this work makes it possible to test the complexity of the distribution without specifying any particular probabilistic model. Two null hypotheses, the number of modes in magnitude density equals 1 and the number of bumps in magnitude density equals 1, have been considered. Their alternatives mean that the magnitude population has a multicomponent structure. In two out of three studied cases the significance of the null hypotheses is less than 10%, which indicates that the magnitude distribution follows neither the log linear nor any smoothly non–log linear law but is more complex. Consequently, when the log linear model is applied to represent the magnitude distribution of each of the cases studied, estimates of mean return periods dramatically disagree with earthquake recurrence observations. The most significant differences are for large magnitude range; that is, such return period estimates are the most erroneous for large earthquakes. It has also been shown that the hazard estimation can be improved considerably by using the model‐free approach with the kernel estimator of magnitude density. This approach ensures a satisfactory agreement between the mean return period estimates and actual observations, and in most of the cases, the agreement is very good.
Effect of pressure on the viscosity of Fe‐S and Fe‐C liquids up to 16 GPa
Authors: Terasaki H. , Suzuki A. , Ohtani E. , Nishida K. , Sakamaki T. , Funakoshi K.
Published: November 2006

The viscosity of liquid Fe78S22 was measured up to 16 GPa and 1723 K using a high‐speed CCD camera system (125 frames/s maximum). In order to prevent a chemical reaction between the sample and a Re viscosity marker sphere, the Re spheres were coated with alumina to a thickness of 1–2 μm. The measured viscosity coefficients were 3.2–8.5 mPa‐s and the activation volume was estimated to be 1.46 cm3/mol. The viscosity of liquid Fe86C14 was also measured up to 4.5 GPa and 1843 K. The viscosity coefficients were 3.8–6.3 mPa‐s. There was no large difference in viscosity coefficient and activation volume between the Fe‐S and Fe‐C eutectic liquids in the range of measurement. Viscosities of Fe‐S and Fe‐C eutectic liquids are likely to remain low in the planetary interior.
Two‐dimensional electrical section beneath the eastern margin of Japan Sea
Authors: Toh Hiroaki , Baba Kiyoshi , Ichiki Masahiro , Motobayashi Tsutomu , Ogawa Yasuo , Mishina Masa'aki , Takahashi Ichiro
Published: November 2006

Four ocean bottom electromagnetometers provided seafloor geoelectromagnetic data for more than nine months in order to reveal mantle dynamics beneath the eastern margin of Japan Sea, where several large and hazardous earthquakes have repeatedly occurred so far. High‐quality magnetotelluric (MT) data from the seafloor array, together with those of four additional land sites in northeast Japan, were analyzed and carefully corrected for topographic/bathymetric effects to extract two‐dimensional (2D) MT responses at each site. Here we show how the 2D electrical section derived by inverting the corrected 2D MT responses depicts fluid injection deep into the wedge and back‐arc mantle by the cold and fast subducting Pacific plate. A high conductivity anomaly found beneath the Sado Ridge at depths ranging from 150 to 200 km may be direct field evidence that supports water transportation from the Earth's surface to the wedge and back‐arc mantle in the form of serpentinite.
Lost tsunami
Authors: Pareschi Maria Teresa , Boschi Enzo , Favalli Massimiliano
Published: November 2006

Numerical simulations support the occurrence of a catastrophic tsunami impacting all of the eastern Mediterranean in early Holocene. The tsunami was triggered by a debris avalanche from Mt. Etna (Sicily, Italy) which entered the Ionian Sea in the order of minutes. Simulations show that the resulting tsunami waves were able to destabilize soft marine sediments across the Ionian Sea floor. This generated the well‐known, sporadically located, “homogenite” deposits of the Ionian Sea, and the widespread megaturbidite deposits of the Ionian and Sirte Abyssal Plains. It is possible that, ∼8 ka B.P., the Neolithic village of Atlit‐Yam (Israel) was abandoned because of impact by the same Etna tsunami. Two other Pleistocenic megaturbidite deposits of the Ionian Sea can be explained by previous sector collapses from the Etna area.
Thermally induced inversion of Al‐substituted titanomagnetite in basalts: Evidence for partial self‐reversal
Authors: Pan Yongxin , Liu Qingsong , Deng Chenglong , Qin Huafeng , Zhu Rixiang
Published: November 2006

We report properties of laboratory‐induced thermoremanence combined with detailed rock magnetic experiments on basaltic samples which contain aluminum‐substituted titanomagnetite (Fe2.24Ti0.64Al0.12O4). Prior to Thellier‐Coe paleointensity experiments, specimens were first demagnetized using an alternating field with a peak field of 90 mT and were then imparted an anhysteretic remanent magnetization (ARM) to represent a natural remanent magnetization (NRM). Results show that the partial thermal remanent magnetization (pTRM) gain and ARM remaining are linearly correlated up to 300°C. Between 300 and 460°C, specimens acquire thermoremanence with a direction antiparallel to the external field direction, leading to intensity decreases. This coincides with the onset of the mineral transformation from Al‐titanomagnetite to a magnetic phase with higher Tc. Our results support that phase interaction with distinct Tc values in partially oxidized titanomagnetite can produce partial self‐reversal thermoremanence in rocks.
Effects of the Earth's rotation and bottom slope on a density current descending a sloping bottom
Authors: Tanaka Kiyoshi
Published: November 2006

The dynamic and transport processes associated with the descent of dense water along a sloping bottom are investigated by numerical experiments. The focus is on effects of the Earth's rotation (the Coriolis parameter f) and bottom slope (inclination S). Before baroclinic instability grows to finite amplitude (development stage), downslope volume transport agrees roughly with an estimate based on the Ekman layer theory. The volume transport decreases with increasing f, and it is larger in steep slope cases. The offshore extension scale of the dense water region is mainly determined by internal radius of deformation, which decreases with increasing f and increases with increasing S. The growth rate of the baroclinic instability increases with increasing f and S. The baroclinic instability is also affected by energy transfer due to Reynolds stress, especially in the low‐ and mid‐latitude regions. After the instability grows to finite amplitude (mature stage), the dense water is effectively transported offshore by the eddy flows. The eddy transport decreases with increasing f, and it is lower in steep slope cases than in gentle slope cases. That is, although the flow instability becomes stronger with increasing f and S in the development stage, the offshore eddy transport of dense water becomes less efficient with increasing f and S in the mature stage. The mechanisms of these effects are also examined in detail.
Modeling of net ecosystem exchange and its components for a humid grassland ecosystem
Authors: Lawton Delphine , Leahy Paul , Kiely Ger , Byrne Kenneth A. , Calanca Pierluigi
Published: November 2006

We measured the net ecosystem exchange (NEE) of a managed humid grassland in southwest Ireland from 2002 to 2004 with an eddy covariance (EC) system. In addition, a process‐based biogeochemical model (PaSim) incorporating land management practices such as grazing and grass harvesting was used to simulate the carbon dynamics. The modeled NEE of 2.6, 2.7 and 3.4 t C ha−1 (uptake) for 2002, 2003 and 2004 compares well with the measured NEE of 1.9, 2.6 and 2.9 t C ha−1. There is good agreement between the model output and the EC observations in the growing season but not so good in the winter period. The year‐on‐year increase in measured NEE is partly attributed to a circa 4% year‐on‐year increase in annual photosynthetic photon flux density (QPPFD). The year of lowest NEE (2002) was associated with highest rainfall (1785 mm) and lowest QPPFD. In the wettest year, grass harvesting was delayed by a month, resulting in a reduced NEE. The management of grassland in regions of high rainfall is dependent on weather conditions. If wet conditions become more prevalent (e.g., as a result of climate change), grasslands in such regions may shift from intensive to extensive management with further reductions in NEE. The reasonable agreement between the model predictions and the EC measurements demonstrates the potential of the model for applications such as upscaling EC measurements to regional scales and predicting responses of grasslands to climate change.
Positive reactions on Western blots do not necessarily indicate the epitopes on antigens are continuous
Authors: Zhou Yi‐Hua , Chen Zhaochun , Purcell Robert H , Emerson Suzanne U
Published: November 2006

Epitope mapping (identification of an antigenic site recognized by an antibody) is an important component of vaccine development and immunological assays. It is widely accepted that in Western blots, antibodies react exclusively with continuous epitopes: discontinuous epitopes are assumed to be irreversibly destroyed by electrophoresis under the denaturing conditions used for sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Here, we demonstrate that the epitopes recognized by four different monoclonal antibodies were identified as discontinuous epitopes when characterized by radioimmunoprecipitation assays and enzyme‐linked immunosorbent assays, yet each of these antibodies reacted with the corresponding antigen on Western blots. Reaction on Western blots may be due to epitope renaturation during or after the transfer of the protein to a membrane. Therefore, positive reactions on Western blots do not necessarily indicate that epitopes are continuous and this caveat should be kept in mind while characterizing them.