bluuebunny/crossref_metadata_2025 huggingface dataset:
Uniform Fatty Acid Mobilization from Anatomically Distinct Fat Depots in the Sable (Martes zibellina)
Authors: Nieminen Petteri , Mustonen Anne‐Mari
Published: June 2007

The mobilization of fatty acids (FA) is a selective process in humans, rodents and the few previously studied carnivores. The FA composition of and mobilization from different fat depots reflect the functions of adipose tissues, e.g. in energy storage or insulation. Sixteen farm‐raised sables (Martes zibellina), a terrestrial mustelid, were assigned into a fed control group or fasted for 4 days. The FA composition of the sable was relatively similar to other previously studied mustelids. The masses of the different fat depots decreased by 28–55% during fasting. The subcutaneous (sc) and intraabdominal (iab) fats had a uniform FA composition and the sable could mobilize both sc and iab FA. 18:3n‐3, 18:4n‐3 and 16:1n‐7 were effectively mobilized, while long‐chain saturated (SFA) and monounsaturated FA (MUFA) increased in proportion. Relative mobilization (RM) correlated inversely with the FA chain length and Δ9‐desaturation increased RM of several MUFA compared to SFA. The results reinforce the hypothesis that the terrestrial sable can utilize sc and iab fat depots as energy reserves during nutritional scarcity. The natural history of the species is an important determinant of the FA composition and RM between anatomically different fat depots.
Polar and Neutral Lipid Composition in the Pelagic TunicatePyrosoma atlanticum
Authors: Mayzaud Patrick , Boutoute Marc , Perissinotto Renzo , Nichols Peter
Published: June 2007

Structure and functioning of colonial pyrosomes are largely undescribed and their lipid characteristics have received limited attention. The aim of this paper is to fill this gap on one of the dominant speciesPyrosoma atlanticum. Lipid content is tightly coupled to size and weight. Lipid composition shows a large dominance of structural polar lipids. Neutral lipids were dominated by sterols with low levels of acylglycerols and free fatty acids. Phospholipids show a dominance of PC with intermediate percentages of PE and DPG. Other constituents (PS, PI, LPC, sphingolipids) were present at lower levels. Fatty acid composition of DAG and TAG showed a dominance of saturated acids (16:0, 14:0), DHA and intermediate levels of MUFA. Phospholipids were dominated by DHA with values exceeding 30% of total FA in all categories except for PI, where lower percentages occurred. Saturated acids were second in abundance with MUFA showing intermediate concentrations. Sterols were dominated by 24‐methylcholesta‐5,22E‐dien‐3β‐ol with more than 22% of the total sterol. Cholesterol (cholest‐5‐en‐3β‐ol) represented only 12 % of the total while 24‐methylcholesta‐5,24(28)E‐dien‐3β‐ol accounted for 11% of the total sterols. The low levels of triacylglycerols and free fatty acids, coupled with high concentrations of glycolipids and phytoplankton‐derived degraded chloropigments, is evidence of a direct link with the digestive activity and substantiate the idea of a high physiological turnover as an alternative to large lipid accumulation. The fatty acid and sterol profiles are consistent with a diverse phytoplankton diet, and a strong contribution of phospholipid classes to energy needs, including locomotion.
Diesters from Oleic Acid: Synthesis, Low Temperature Properties, and Oxidation Stability
Authors: Moser Bryan R. , Sharma Brajendra K. , Doll Kenneth M. , Erhan Sevim Z.
Published: May 2007

Several diesters were prepared from commercially available oleic acid and common organic acids. The key step in the three step synthesis of oleochemical diesters entails a ring opening esterification of alkyl 9,10‐epoxyoctadecanoates (alkyl: propyl, isopropyl, octyl, 2‐ethylhexyl) using propionic and octanoic acids without the need for either solvent or catalyst. Each synthetic diester was evaluated for both low temperature operability and oxidation stability through measurement of cloud point, pour point, oxidation onset temperature, and signal maximum temperature. It was discovered that increasing chain length of the mid‐chain ester and branching in the end‐chain ester had a positive influence on the low temperature properties of diesters. Improved oxidation stability is achieved when the chain length of the mid‐chain ester is decreased. Additionally, the mid‐chain ester plays a larger role in oxidation stability than the end‐chain ester. These products may prove useful in the search for bio‐based industrial materials, such as lubricants, surfactants, and fuel additives.
Collaborative test of determination of iodine value in fish oils. 1. Reaction time and carbon tetrachloride or cyclohexane as solvents
Authors: Barlow Stuart M. , Bimbo Anthony P. , Miller Eric L. , Thorisson Snorri , Walters D. E.
Published: May 2007

Twenty‐two laboratories participated in a collaborative test to determine the iodine value (IV) of eight samples of fish oil (four with IV<150, four with IV>150) with either carbon tetrachloride (AOCS Official Method Cd 1–25) or cyclohexane (AOCS Recommended Practice Cd 1b‐87) as solvent and either 1 or 2 h of reaction time. Laboratories received coded duplicate samples (hidden duplicates) and carried out duplicate determinations on each oil by each solvent‐time combination (open duplicates). Replacing carbon tetrachloride with cyclohexane resulted in a lower IV (P<0.001). The decrease averaged 1.6 IV units for low‐IV oils and 3.8 IV units for high‐IV oils; this difference in response of 2.2 IV units between low‐ and high‐IV oils was significant (P<0.001). Increasing the reaction time had a relatively small effect (0.34±0.18). There was no interaction of reaction time with solvent or oil type. Cyclohexane caused emulsions, which made it difficult to titrate residual iodine and thus increased the variability of the determination. The repeatability standard deviations (sr), based on hidden duplicates, for 1‐h reaction time with carbon tetrachloride and cyclohexane were 2.17 and 3.35, respectively. The corresponding reproducibility standard deviations were 2.73 and 4.53.
An original transesterification route for fatty acid ester production from vegetable oils in a solvent‐free system
Authors: Goma‐Doncescu N. , Legoy M. D.
Published: May 2007

Wax ester production from a long‐chain alcohol and methyl ester has been investigated with an immobilized thermostable lipase (lipozyme IM from Novo Nordisk). The transesterification reaction rate was monitored in solvent‐free medium that was exclusively composed of the reactants and the enzyme. The transesterification is performed by simply mixing the two substrates in various stoichiometric amounts at a temperature range from 55 to 65°C under constant stirring in the presence of low concentrations of enzyme preparation (0.12 to 2%, w/w). Long‐chain reactants produce waxes of high molecular mass that induce low solubility and high viscosity. On average, high transesterification yields are obtained (around 95%). Thermodynamic parameters involving substrate concentration and temperature have also been investigated. The balance between optimal working temperature and the molar ratio of substrates in such a complex medium appears to be 60°C, with a molar ratio methyl oleate/stearyl alcohol of 1:0.5. Substrate inhibition due to stearyl alcohol has been observed. A study of kinetic parameters has confirmed these results.
Seasonal changes in the lipid classes and fatty acid compositions of hake (Merluccius hubbsi) liver oil
Authors: Méndez Eduardo
Published: May 2007

The lipid content, lipid class composition, and fatty acid composition of hake (Merluccius hubbsi) liver oil was studied for a whole year. The lipid content of the liver ranged from 41 to 60%. Triacylglycerols were the main lipid class present in the oil, with a mean value of 80%. Docosahexaenoic acid was the main polyunsaturated fatty acid during the year and was twice that of the eicosapentaenoic acid content. The composition of hake liver oil makes it useful as a raw material for encapsulated pharmaceutical products.
Catalytic hydrogenation of linoleic acid over platinum‐group metals supported on alumina
Authors: Kitayama Yoshie , Muraoka Masahiro , Takahashi Megumi , Kodama Tatsuya , Takahashi Eriko , Okamura Mutsuo
Published: May 2007

Catalytic activity and selectivity for hydrogenation of linoleic acid (cis‐9,cis‐12 18:2) were studied on Pt, Pd, Ru, and Ir supported on Al2O3. Stearic acid (18:0) and 10 different octadecenoic isomers (18:1) in the products could be separated completely by using a new capillary column coated by isocyanopropyl trisilphenylene siloxane for gas‐liquid chromatography. The monoenoic acid isomers and dienoic acid isomers in the products on the various catalysts showed different distributions. The catalysts exhibited nearly equal selectivity for stearic acid formation. The 12‐position double bond in linoleic acid has higher reactivity than the 9‐position double bond in catalytic hydrogenation on platinum‐group metal catalysts. In addition to hydrogenation products of linoleic acid, geometrical and positional dienoic acid isomers (trans‐9,trans‐12; trans‐8,cis‐12; cis‐9,trans‐13; trans‐9,cis‐13; cis‐9,trans‐12 18:2), due to isomerization of linoleic acid during hydrogenation, were contained in the reaction products. Ru/Al2O3 exhibited the highest activity for isomerization of linoleic acid with the noble metal catalysts. Conjugated octadecadienoic acid isomers have been observed in products of the reaction on Pt/Al2O3, Ru/Al2O3, and Ir/Al2O3. Catalytic activities of noble metals for positional and geometric isomerization of linoleic acid during hydrogenation decreased in the sequence of Ru ≥ Pt > Ir » Pd.
Effect of chlorine dioxide treatment on lipid oxidation and fatty acid composition in salmon and red grouper fillets
Authors: Kim Jeongmok , Lee Yangsoon , O’Keefe Sean F. , Wei Cheng‐i
Published: May 2007

Chlorine dioxide (CIO2) has been explored as a potential substitute for aqueous chlorine to clean seafood products. In an attempt to understand the interaction of CIO2 with organic compounds, duplicate fillets of Atlantic salmon (Salmo salar) and red grouper (Epinephelus morio) were treated for 5 min with freshly prepared aqueous CIO2 at 20, 40, 100, and 200 ppm total available CIO2 in 3.5% brine. Thiobarbituric acid (TBA) values and fatty acid composition were determined. CIO2‐treated salmon and red grouper showed a dose‐related increase in TBA; the 100 and 200 ppm groups had significantly (P<0.05) greater TBA values than controls and the 20 ppm group. Treated red grouper and salmon did not differ in percentage monounsaturated and polyunsaturated fatty acids compared to controls, although differences occurred with some individual fatty acids. Thus, CIO2 treatment did not greatly affect fatty acid composition of treated fillets.
Effects of selected substrate forms on the synthesis of structured lipids by two immobilized lipases
Authors: Lee Ki‐Teak , Akoh Casimir C.
Published: May 2007

Two immobilized lipases, IM 60 from Rhizomucor miehei and SP 435 from Candida antarctica, were used to synthesize structured lipids (SL). Tricaprin and trilinolein were interesterified to produce SL that contained one linoleic acid per triacylglycerol molecule (SL1) and SL with two linoleic acids (SL2). SL1 and SL2 were separated by silver nitrate thin‐layer chromatography according to their unsaturation, and the fatty acid at the sn‐2 position was determined after pancreatic lipasecatalyzed hydrolysis of SL1 and SL2. With IM 60, 57.7 mol% capric acid and 42.3 mol% linoleic acid were found at the sn‐2 position of SL1, while 43.3 mol% capric acid and 56.7 mol% linoleic acid were at the sn‐2 position of SL2. The fatty acid at the sn‐2 position of SL1 with SP 435 as biocatalyst was 43.6 mol% capric acid and 56.4 mol% linoleic acid, while SL2 contained 56.6 mol% capric acid and 43.4 mol% linoleic acid. Different structural forms of the capric acid‐containing substrate (triacylglycerol vs. ethyl ester) and different chainlengths of triacylglycerol were selected to study the substrate selectivity of lipases. Results indicated that SP 435 had some degree of preference for the triacylglycerol form (tricaprin), and IM 60 produced SL more rapidly and reached steady state faster with tricaprin as substrate than with capric acid ethyl ester. For chainlength selectivity, mol% of synthesized SL from tricaprin + trilinolein and tristearin + trilinolein were compared. SP 435 exhibited no apparent preference for either tricaprin or tristearin. However, IM 60 showed a more rapid reaction with tricaprin than with tristearin.
Synthesis of oligoethylene glycol ethers from the seed oil of Vernonia anthelmintica
Authors: Singh Sukhprit
Published: May 2007

The seed oil of Vernonia anthelmintica on reaction with diols (mono‐, di‐, tri‐, or tetraethylene glycols) in the presence of boron trifluoride etherate, followed by saponification and esterification (methanol/H+), gives the oligoethylene glycol ethers: methyl 12(13)‐hydroxy‐13(12) [2‐hydroxy‐ethyl‐1‐oxy]‐octadec‐9‐enoate; methyl 12(13)‐hydroxy‐13(12)‐[5‐hydroxy‐3‐oxapentyl‐1‐oxy]‐octadec‐9‐enoate; methyl 12(13)‐hydroxy‐13(12)‐[8‐hydroxy‐3,6‐dioxaoctyl‐1‐oxy]‐octadec‐9‐enoate; and methyl 12(13)‐hydroxy‐13(12)‐[11‐hydroxy‐3,6,9‐trioxaundecyl‐1‐oxy]‐octadec‐9‐enoate. Methyl 12,13‐dihydroxyoctadec‐9‐enoate is a co‐product in all reactions.
Design of a single‐stage mechanical fat separator
Authors: Onwulata C. I. , Goldberg N.
Published: May 2007

Thermal fractionation of highly saturated fats can address the current nutritional concerns related to the amount, type, and saturated‐fat level of lipids in foods. Separation of fats into different melting fractions allows for tailoring natural fats into functional and nutritional groups, while also allowing for the use of the less desirable fractions in nonfood applications. The single‐stage laboratory‐scale separator described herein separates fats into two gross melting fractions, termed high and low. The latter fractions can be further separated by adjusting the cooling zone temperatures, resulting in secondary fractions with different melt patterns. Thermal analysis of the hard fractions shows a 10–15°C shift to a higher melting point.
α‐Melt‐mediated crystallization of 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl‐sn‐glycerol
Authors: Rousset Ph. , Rappaz M.
Published: May 2007

The α‐melt‐mediated crystallization of 1‐palmitoyl‐2‐oleoyl‐3‐stearoyl‐sn‐glycerol (POS) has been investigated by differential scanning calorimetry (DSC), combined with polarized‐light microscopy. Starting from a completely liquid state, the melt was first cooled down and maintained at a temperature, T1, during a time, t1, where the α‐phase formed. Then it was heated to a temperature, T2, above the melting point of α for isothermal solidification into a solid phase, which was identified as δ. Based upon DSC solidification peaks, the time‐temperature‐transformation (TTT) diagram of POS was constructed for these solidification conditions and was compared with the TTT diagram of direct crystallization from the melt. The α‐melt‐mediated solidification showed accelerated kinetics of the δ‐phase. The effects of T1 and t1 were also studied: at short t1, crystallization was faster with a decreasing value of T1, whereas the opposite trend was observed for a longer plateau at T1. These tendencies were interpreted in terms of three competing phenomena: the density of δ‐nuclei that can form during the plateau at T1, α‐δ solid‐state transformation, and memory effects of molecule arrangements in the α‐remelted phase.
Enrichment of lesquerolic and auricolic acids from hydrolyzed Lesquerella fendleri and L. gordonii oil by crystallization
Authors: Frykman Hans B. , Isbell Terry A.
Published: May 2007

Lesquerolic and auricolic acids were obtained from hydrolyzed lesquerella oil by a low‐temperature crystallization procedure. The lesquerolic and auricolic fatty acid fraction was enriched from 55–59% to 85–99% with high yields (94%). Washing the free fatty acids with pH 6.0 buffer provided reproducible crystallizations of those hydroxy fatty acids. In contrast, when hydrolyzed oil from Lesquerella fendleri was not buffer‐washed, there was, in most cases, no separation of hydroxy fatty acids by crystallization. This crystallization procedure is suitable for a large‐scale separation process of the hydroxy fatty acids from nonhydroxy fatty acids obtained from hydrolyzed lesquerella oil.
On‐line chemical database for new crop seeds
Authors: Abbott T. P. , Phillips B. S. , Butterfield R. O. , Isbell T. A. , Kleiman R.
Published: May 2007

Since the 1950s, a database of the chemical composition of seeds, collected throughout the world, has been generated at the National Center for Agricultural Utilization Research. Information contained in the database is primarily selected chemical and physical properties of seed oils. Over more than 38 years, 15,738 accessions of 7,924 species of 2,339 genera from 225 families were collected and analyzed. This database is now accessible on the Internet at http://www.ncaur.usda.gov/nc/ncdb/search.html.ssi. This paper gives an overview of the database, describes the information available, and illustrates how to do searches.
Chain‐breaking fused heterocyclic antioxidants: Antioxidant activities of 9H‐xanthene‐2,7‐diols and α‐tocopherol upon liposomal membranes
Authors: Yamamura Tatsuo , Ishida Takafumi , Tatara Hiroyuki , Nishiyama Tomihiro
Published: May 2007

We evaluated the antioxidant activities of 9H‐xanthene‐2,7‐diols and α‐tocopherol (α‐Toc) upon the oxidation of soybean phosphatidylcholine liposomal membranes, induced by 2,2′‐azobis(2‐amidinopropane) dihydrochloride (AAPH) and 2,2′‐azobis(2,4‐dimethylvaleronitrile (AMVN). The stoichiometric factors of 9H‐xanthene‐2,7‐diols, initiated with water‐soluble AAPH and lipid‐soluble AMVN, were 1.9–2.7 and 1.2–1.8‐fold greater than those of α‐Toc, respectively. The consumption profile of the antioxidant confirmed that 9H‐xanthene‐2,7‐diol was completely consumed within the induction period (tinh) and that the 9H‐xanthene‐2,7‐diol oxidation product was formed. When all oxidation product was depleted, tinh was terminated, and rapid oxidation occurred. These results suggested that the antioxidant activities of 9H‐xanthene‐2,7‐diol depend not only on the initial hydrogen abstraction from 9H‐xanthene‐2,7‐diol but also on a second hydrogen abstraction from the residual phenolic OH group of the oxidation product. Ascorbic acid (AsA) could not scavenge the radicals by itself in the lipid bilayer. However, when 9H‐xanthene‐2,7‐diol was located in the lipid bilayer, the addition of AsA into the aqueous phase prolonged tinh and reduced the rate of decay of 9H‐xanthene‐2,7‐diol.
Interactions between volatiles and lipids in complex systems
Authors: Le Thanh M. , Goubet I. , Le Quere J. L. , Voilley A.
Published: May 2007

Partition equilibria of three aroma compounds in three different biphasic systems were studied by a liquid/liquid partition technique to investigate interactions that occur between volatiles and lipids in biphasic solutions. The lipids used were linoleic acid and ricinoleic acid and tetradecane as a model. The three aroma compounds were ethyl acetate, 2,5‐dimethylpyrazine, and oct‐1‐en‐3‐ol. The results showed that the intermolecular forces involved were weak. Infrared spectroscopy was then performed on binary systems (tetradecane and linoleic acid or aroma compound) and on ternary systems (tetradecane, linoleic acid, and aroma compound) to determine the nature of the interactions. This method confirmed the presence of hydrogen bonds between linoleic acid and 2,5‐dimethylpyrazine or oct‐1‐en‐3‐ol and also between molecules of oct‐1‐en‐3‐ol when the latter are present at high concentrations in lipids. The observations provided sufficient information to explain the behavior of oct‐1‐en‐3‐ol in biphasic solutions, but further work is needed to fully elucidate the nature of interactions between ethyl acetate or 2,5‐dimethylpyrazine and lipids and also to explain the behavior of these compounds in biphasic solutions.
Adhesion of edible oils to food contact surfaces
Authors: Michalski Marie‐Caroline , Desobry Stéphane , Pons Marie‐Noëlle , Hardy Joël
Published: May 2007

Adhesion of oils and fatty food products to packages is an important storage problem, because it increases product‐package interactions that alter quality. Reducing such adhesion would also allow savings in recycling and cleaning processes. The aim of our work was to test if some thermodynamical adhesion models were correlated to edible oils’ bulk adhesion as measured experimentally. Food‐contact surfaces were low‐density polyethylene, polyethylene teraphthalate, stainless steel, and glass. The Young‐Dupré equation and five models of adhesion from the literature were used to calculate solids’ surface tension and the thermodynamical work of adhesion (Wa). The dispersive, polar, acid‐base, and hydrogen surface tension components of oils and solids were calculated. The experimental adhesion, or amount of edible oils remaining on solid surfaces after contact, was found to be correlated to Young‐Dupré Wa, involving contact angle measured by specially designed image analysis technique. Two models, involving, respectively, surface tension’s hydrogen component and a linear dependence of Wap on the liquid polar surface tension component, fitted best with oil bulk adhesion as measured experimentally. Our theoretical approach to fatty food material adhesion seems, so far, consistent to predict global residues of edible oils on solid surfaces.
Hybrid magma generation preceding Plinian silicic eruptions at Hekla, Iceland: evidence from mineralogy and chemistry of two zoned deposits
Authors: SVERRISDOTTIR GUDRUN
Published: May 2007

Hekla is a Holocene volcanic ridge in southern Iceland, which is notable for the link between repose periods and the composition of the first-erupted magma. The two largest explosive silicic eruptions, H4 and H3, erupted about 4200 and 3000 years ago. Airfall deposits from these eruptions were sampled in detail and analysed for major and trace elements, along with microprobe analyses of minerals and glasses. Both deposits show compositional variation ranging from 72 % to 56 % SiO2, with mineralogical evidence of equilibrium crystallization in the early erupted rhyolitic component but disequilibrium in the later erupted basaltic andesite component. The eruptions started with production of rhyolitic magma followed by dacitic to basaltic andesite magma. Sparse crystallization of the intermediate magma and predominant reverse zoning of minerals, trending towards a common surface composition, indicate magma mixing between rhyolite and a basaltic andesite end-member. The suggested model involves partial melting of older tholeiitic crust to produce silicic magma, which segregated and accumulated in deep crustal reservoir. Silicic magma eruption is triggered by basaltic andesite dyke injection, with a proportion of the dyke magma contributing to the production and eruption of a mixed hybrid magma. Both the volume of the silicic partial melt, and the proportion of the hybrid magma depend on the pre-eruptive repose time.
Contrasting origins of late Mesozoic adakitic granitoids from the northwestern Jiaodong Peninsula, east China: implications for crustal thickening to delamination
Authors: HOU MING-LAN , JIANG YAO-HUI , JIANG SHAO-YONG , LING HONG-FEI , ZHAO KUI-DONG
Published: May 2007

Two suites of granitoids, the Late Jurassic (158 ± 3 Ma) Linglong suite and the Early Cretaceous (130–126 Ma) Guojialing suite, crop out in the northwestern Jiaodong Peninsula, eastern China. The Linglong suite is a monzogranite, comprising alkali feldspar, plagioclase, quartz and Fe-rich biotite. The Guojialing suite includes at least five plutonic bodies of both granodiorite and monzo-granite. The rocks are composed of plagioclase, alkali feldspar, quartz, Mg-rich amphibole and Mg-rich biotite. Both the Linglong and Guojialing suites have adakitic affinity. They are enriched in LREE with high La/Yb ratios and show positive Eu anomalies. The rocks are also enriched in LILE and depleted in HFSE with high Sr/Y ratios. The Linglong granite shows very uniform Sr–Nd isotopic compositions with initial 87Sr/86Sr ratios of 0.7119–0.7126 and εNd (T) values of −21.3 to −21.6, which are similar to those of the local Neoarchaean basement. The Guojialing suite has variable initial 87Sr/86Sr ratios (0.7108–0.7120) and εNd (T) values (−10.8 to −17.2), which are distinct both from those of the Neoarchaean basement and from those of the local enriched lithospheric mantle inferred from the coeval mafic dykes in the studied area. Detailed petrological and geochemical data indicate that the Linglong suite was derived by partial melting of Neoarchaean metamorphic lower-crustal rocks at depth of > 50 km with a eclogite residue, whereas the Guojialing suite was formed by the reaction of delaminated eclogitic crust-derived melt with the upwelling asthenospheric mantle. The petrogenesis of these two contrasting adakitic granitoids suggests intensive lower-crustal delamination during Early Cretaceous times, following a crustal thickening process from the late stage of the Early Jurassic to early stage of the Late Jurassic with crustal thickness of < 32 km to > 50 km, respectively.
ARISTOTLE ON THE MIXED CONSTITUTION AND ITS RELEVANCE FOR AMERICAN
POLITICAL THOUGHT
Authors: Biondi Carrie-Ann
Published: May 2007

Contemporary political discourse is marked with the language of
democracy, and Western countries in particular seek to promote democracy
at home and abroad. However, there is a sublimated conflict in general
political discourse between a desire to rely on alleged political experts
and a desire to assert the supposed common sense of all men. Can the
struggle between the democratic and aristocratic values embodied in this
conflict be reconciled? The question is perennial, and raises issues that
are central to constitutional design. Aristotle, developing in significant
ways insights made by his teacher Plato, grapples with it in his
Politics. Aristotle's views on these matters are
relevant—by way of the American Founders'—to contemporary
American politics and modern democracies generally. During the eighteenth
century, the Founders, some of whom explicitly reached back to Aristotle's
work, also struggled—especially in The Federalist
Papers—with these thorny issues of constitutional design. They
created the U.S. Constitution in part to address these very same
problems and issues. We are living in some ways, then, in the shadow of
Aristotle's political theorizing, albeit as transposed by the American
Founders. Both Aristotle and some of the American Founders theoretically
favor aristocracy over democracy, but concede that in practice a blend of
the two has to be integrated into the fundamental structure of political
society. We need to reconnect with these important political discussions
in order to come to terms with aristocratic and democratic values in our
current circumstances.
Optimal payment of mortgages
Authors: XIE DEJUN , CHEN XINFU , CHADAM JOHN
Published: May 2007

This article provides a borrower's optimal strategies to terminate a mortgage with a fixed interest rate by paying the outstanding balance all at once. The problem is modelled as a free boundary problem for the appropriate analogue of the Black-Scholes pricing equation under the assumption of the Vasicek model for the short-term rate of investment. Here the free boundary provides the optimal time at which the mortgage contract is to be terminated. A number of integral identities are derived and then used to design efficient numerical codes for computing the free boundary. For numerical simulation, parameters for the Vasicek model are estimated via the method of maximum likelihood estimation using 40 years of data from US government bonds. The asymptotic behaviour of the free boundary for the infinite horizon is fully analysed. Interpolating this infinite horizon behaviour and a known near-expiry behaviour, two simple analytical approximation formulas for the optimal exercise boundary are proposed. Numerical evidence shows that the enhanced version of the approximation formula is amazingly accurate; in general, its relative error is less than 1%, for all time before expiry.
A comparative study of methods for diagnosis of obesity in an urban mixed-race population in Minas Gerais, Brazil
Authors: de Freitas Silvia Nascimento , Caiaffa Waleska Teixeira , César Cibele Comini , Cândido Ana Paula Carlos , Faria Valéria Andrade , Neto Raimundo Marques do Nascimento , Machado-Coelho George Luiz Lins
Published: May 2007

Background

Obesity is defined as an excess of total body fat and may be assessed by different methods. The objective of the present study was to establish the discriminatory power of anthropometric data in determining obesity.

Methods

The subjects comprised 685 individuals, aged 20–79 years, sampled from a population-based survey. The following indicators were used: body mass index (BMI), waist circumference (WC) and total body fat percentage estimated with both Siri's equation (%BF Siri) and foot-to-foot bioelectrical impedance analysis (%BF BIA). Sensitivity and specificity of different cut-off points for each method were determined using %BF BIA as reference.

Results

Of 685 participants, 57.6% were aged ≥ 40 years, 69.9% were women and 72.6% self-referred themselves as non-white. To classify obesity based on sex and age among women aged < 40 years, the cut-off points were BMI of 26.0 kg m− 2, WC of 84.0 cm and %BF Siri of 34.0%; in those aged ≥ 40 years, the cut-off points were 28.0 kg m− 2, 90.0 cm and 37.4%, respectively. The cut-off points among men aged < 40 years were BMI of 26.3 kg m− 2, WC of 86.0 cm and %BF Siri of 22.5%, and in those aged ≥ 40 years, 26.3 kg m− 2, 89.0 cm and 24.5%, respectively. BMI was the method with the largest area under the curve (AUC) independent of sex and sex/age, yet no differences were observed in AUC between BMI and WC (P>0.05). Classifying according to skin colour did not change cut-off points in any indicator.

Conclusion

BMI and WC better discriminate obesity among women and men aged ≥ 40 years from a mixed-race population.
Role of the Southern Annular Mode (SAM) in Southern Ocean CO2 uptake
Authors: Lenton Andrew , Matear Richard J.
Published: May 2007

A biogeochemical ocean general circulation model, driven with NCEP‐R1 and observed atmospheric CO2 history, is used to investigate and quantify the role that the Southern Annular Mode (SAM), identified as the leading mode of climate variability, has in driving interannual variability in Southern Ocean air‐sea CO2 fluxes between 1980 and 2000. Our simulations show the Southern Ocean to be a region of decreased CO2 uptake during the positive SAM phase. The SAM induces changes in Southern Ocean CO2 uptake with a 2‐month time lag explaining 42% of the variance in the total interannual variability in air‐sea CO2 fluxes. Our analysis shows that the response of the Southern Ocean to the SAM is primarily governed by changes in ΔpCO2 (67%), and that this response is driven by changes in ocean physics that control the supply of nutrients to the upper ocean, primarily Dissolved Inorganic Carbon (DIC). The SAM is predicted to become stronger and more positive in response to climate change and our results suggest this will decrease the Southern Ocean CO2 uptake by 0.1PgC/yr per unit change in the SAM.
Element fluxes from the volcanic front of Nicaragua and Costa Rica
Authors: Carr Michael J. , Saginor Ian , Alvarado Guillermo E. , Bolge Louise L. , Lindsay Fara N. , Milidakis Kathy , Turrin Brent D. , Feigenson Mark D. , Swisher Carl C.
Published: June 2007

Geochronologic and geological data define a 600 ka age for the current volcanic front in Costa Rica. In Nicaragua, this age is less constrained but is likely within the range 600 ka to 330 ka. In Costa Rica, the new geochronologic data significantly improve estimates of the volumes of the volcanoes because they define the contact between the active volcanoes and the previous volcanic front, which is substantially older (2.2 to 1.0 Ma). In addition, the contrast in extrusive volcanic flux between western Nicaragua (1.3 × 1010 kg/m/Myr) and central Costa Rica (2.4 × 1010 kg/m/Myr) is greatly reduced from previous estimates and now within the range of error estimates. We estimate the subducted component of flux for Cs, Rb, Ba, Th, U, K, La, Pb, and Sr by subtracting estimated mantle‐derived contributions from the total element flux. An incompatible element‐rich OIB source for the Cordillera Central segment in Costa Rica makes the subducted element flux there highly sensitive to small changes in the modeled mantle‐derived contribution. For the other three segments studied, the estimated errors in concentrations of highly enriched, subduction‐derived elements (Cs, Ba, K, and Pb) are less than 26%. Averaged over the time of the current episode of volcanism, the subduction‐derived fluxes of Cs, Ba, K, Pb, and Sr are not significantly different among the four segments of the Central American volcanic front in Nicaragua and Costa Rica. The subduction‐derived fluxes of Th and La appear to increase to the SE across Nicaragua and Costa Rica, but the estimated errors in their subduction‐derived concentrations are very high, making this variation questionable. The lack of change in the fluxes of Cs, Ba, K, Pb, and Sr argues that the well‐defined regional variation in Ba/La is the result of changes in the mode or mechanics of fluid delivery into the mantle wedge, not the total amounts of fluids released from the slab. Concentrated or focused fluids in Nicaragua lead to high degrees of melting. Diffuse fluids in Costa Rica cause lower degrees of melting.
Climate impact of black carbon emitted from energy consumption in the world's regions
Authors: Reddy M. Shekar , Boucher Olivier
Published: June 2007

We have used the Laboratoire de Météorologie Dynamique General Circulation Model (LMD GCM) to estimate the contribution of different regions to global black carbon (BC) atmospheric burden and direct radiative forcing (DRF). On the global scale, fossil fuels and biofuels account for 66% and 34% of energy‐related BC emissions, respectively. East and South Asia together contribute more than 50% of the global surface, atmospheric, and top‐of‐atmosphere DRF by BC. The regional contributions to global mean forcings closely follow the respective contributions to atmospheric burden. The global warming potential (GWP) of BC for different regions ranges from 374 to 677 with a global mean of 480. Europe is the largest contributor (63%) to BC deposition at high latitudes. The indirect GWP due to the BC effect on snow albedo is estimated to be largest for Europe (possibly as large as 1200), suggesting that BC emission reductions from this region are more efficient to mitigate climate change.
A statistical study of interplanetary shocks and pressure pulses internal to magnetic clouds
Authors: Collier Michael R. , Lepping Ronald P. , Berdichevsky Daniel B.
Published: June 2007

We have examined Wind field and plasma data over the time period from November of 1994 through August of 2003 to find cases of interplanetary shocks and pressure pulses internal to magnetic clouds for which we could determine accurate shock normal directions. We have found eight cases in 82 clouds, so these shocks and pressure pulses occurred in approximately 10% of the Wind magnetic clouds. Of the eight cases, six were forward shocks and two were pressure pulses. The internal shocks and pressure pulses tend to occur in the latter half of the clouds, i.e., timewise, about two‐thirds of the way through. In every case the magnetic field change is highly compressive at the shock showing little or no change (<10°) in angle during or after the magnitude jump. These shocks and pressure pulses internal to magnetic clouds appear to be associated with outline asymmetric halo coronal mass ejections of greater than average speed which may imply an interaction between an earlier, slower halo CME and a later, faster, off‐center CME driving a strong shock, but other interpretations are possible and they are discussed.
Large‐scale structure of the fast solar wind
Authors: Bisi M. M. , Fallows R. A. , Breen A. R. , Rifai Habbal S. , Jones R. A.
Published: June 2007

We present the results of a comprehensive study of the fast solar wind near solar minimum conditions using interplanetary scintillation (IPS) data taken with the EISCAT system in northern Scandinavia, and a recent extremely long baseline observation using both EISCAT and MERLIN systems. The results from IPS observations suggest that the fast wind inside 100 solar radii (R⊙) can be represented by a two‐mode model in some cases but this distinction is much less clear by in situ distances beyond 1 astronomical unit (215 R⊙). Two distinct fast streams are seen in the extremely long baseline IPS observation; comparison of the IPS line of sight with a synoptic map of white light indicates the faster mode overlies the polar crown and the slower fast mode overlies an equatorial extension of the polar coronal hole.
Refilling of the slot region between the inner and outer electron radiation belts during geomagnetic storms
Authors: Thorne R. M. , Shprits Y. Y. , Meredith N. P. , Horne R. B. , Li W. , Lyons L. R.
Published: June 2007

Energetic electrons (≥50 keV) are injected into the slot region (2 < L < 4) between the inner and outer radiation belts during the early recovery phase of geomagnetic storms. Enhanced convection from the plasma sheet can account for the storm‐time injection at lower energies but does not explain the rapid appearance of higher‐energy electrons (≥150 keV). The effectiveness of either radial diffusion (driven by enhanced ULF waves) or local acceleration (during interactions with enhanced whistler mode chorus emissions), as a potential source for refilling the slot at higher energies, is analyzed for observed conditions during the early recovery phase of the 10 October 1990 storm. We demonstrate that local acceleration, driven by observed chorus emissions, can account for the rapid enhancement in 200–700 keV electrons in the outer slot region near L = 3.3. Radial diffusion is much less effective but may partially contribute to the flux enhancement at lower L. Subsequent outward expansion of the plasmapause during the storm recovery phase effectively terminates local wave acceleration in the slot and prevents acceleration to energies higher than ∼700 keV. A statistical analysis of energetic electron flux enhancements and wave and plasma properties over the entire CRRES mission supports the concept of local wave acceleration as a dominant process for refilling the slot during the main and early recovery phase of storms. For moderate storms, the injection process naturally becomes less effective at energies ≥1 MeV, due to the longer wave acceleration times and additional precipitation loss from scattering by electromagnetic ion cyclotron waves. However, during extreme events when the plasmapause remains compressed for several days, conditions may occur to allow wave acceleration to multi‐MeV energies at locations normally associated with the slot.
Dependence of neutral temperatures in the lower thermosphere on geomagnetic activity
Authors: Aksnes A. , Eastes R. , Budzien S. , Dymond K.
Published: June 2007

The neutral temperature (Tn) in the lower thermosphere has been measured using high‐resolution (0.13 nm) N2 Lyman‐Birge‐Hopfield (LBH) band emissions, taken from the High‐Resolution Ionospheric and Thermospheric Spectrograph (HITS) instrument aboard the Advanced Research and Global Observation Satellite (ARGOS). Tn in the lower thermosphere (below ∼200 km) has been examined for 12 days in 2000 and 2001. During geomagnetically quiet conditions, the observed HITS temperatures (THITS) as a function of latitude and calculations using the NRLMSISE‐00 model are in good agreement. During periods with geomagnetic disturbances, the model temperatures are unable to match the spatial and temporal variations exhibited by the measurements. An analysis of HITS temperatures and measurements of the auroral electrojet index AL indicates that THITS changes typically follow variations in AL obtained between 13 and 18.5 hours earlier. On average, the time delay is 16 hours and 25 min earlier (correlation coefficient of 0.55), yielding the following empirical formula between Tn and AL changes: ΔTn[K] = 2.1 × ΔAL[nT]. Also, the agreement between measured (HITS) and modeled (NRLMSISE‐00) Tn values has been investigated for 8 days with similar geomagnetic conditions, yielding a correlation coefficient of 0.75 between the THITS‐TMSIS agreement and the previously measured AL.
Columnar aerosol properties in Valencia (Spain) by ground‐based Sun photometry
Authors: Estellés Víctor , Martínez‐Lozano José A. , Utrillas María P. , Campanelli Monica
Published: June 2007

In this paper, we present a climatological study of atmospheric aerosols in coastal eastern Spain, by means of experimental measurements using a Cimel CE318‐2 Sun photometer. The aerosol optical depth, Ångström wavelength exponent, size distribution, complex refractive index, asymmetry parameter, and single scattering albedo have been retrieved from these measurements. The columnar water content, as an important parameter for understanding aerosol growth, has also been retrieved. Statistical results of the annual and seasonal variability analysis, mainly related to the usual summer maximum turbidity found in the Mediterranean and European regions, are also shown. The results are linked to the character of the site, located in an urban environment, near the Mediterranean Sea, and frequently affected by dusty air masses of Saharan origin.
Martian exospheric density using Mars Odyssey radio tracking data
Authors: Mazarico E. , Zuber M. T. , Lemoine F. G. , Smith D. E.
Published: May 2007

We present measurements of the density of the Martian atmosphere at ∼400 km altitude. Our analysis used radio tracking data to perform precise orbit determination on the Mars Odyssey spacecraft between March 2002 and November 2005. Recent improvements in a priori physical models make it possible to isolate the contribution of the atmospheric drag from the various forces acting on the spacecraft. For each spacecraft trajectory segment (arc) we adjusted an atmospheric drag coefficient (CD), which scales the a priori model density. From the drag coefficient we obtained a time series of the measured density. These measurements at the Mars Odyssey orbiting altitude are close to noise level, and the various tests we conducted show the robustness of the measurements. We obtained a better agreement with the atmospheric model used during the second Martian year, when solar activity is lower. Using various simple exponential atmosphere models, we estimated the scale height near the spacecraft periapsis and found values between 25 and 50 km, in the lower range of expected values, and used exospheric temperature estimates to assess the role of EUV heating of the upper atmosphere. We did not observe one‐to‐one correlation between solar activity and exospheric density, but we detected a solar rotation periodicity in our measurements.
A‐272651, a nonpeptidic blocker of large‐conductance Ca2+‐activated K+channels, modulates bladder smooth muscle contractility and neuronal action potentials
Authors: Shieh C‐C , Turner S C , Zhang X‐F , Milicic I , Parihar A , Jinkerson T , Wilkins J , Buckner S A , Gopalakrishnan M
Published: May 2007

Background and Purpose:

The large‐conductance Ca2+‐activated K+channel (BKCa, KCa1.1) links membrane excitability with intracellular Ca2+signaling and plays important roles in smooth muscle contraction, neuronal firing, and neuroendocrine secretion. This study reports the characterization of a novel BKCachannel blocker, 2,4‐dimethoxy‐N‐naphthalen‐2‐yl‐benzamide (A‐272651).

Experimental Approach:

86Rb+efflux in HEK‐293 cells expressing BKCawas measured. Effects of A‐272651 on BKCaα‐ and BKCaαβ1‐mediated currents were evaluated by patch‐clamp. Effects on contractility were assessed using low‐frequency electrical field stimulated pig detrusor and spontaneously contracting guinea pig detrusor. Effects of A‐272651 on neuronal activity were determined in rat small diameter dorsal root ganglia (DRG).

Key Results:

A‐272651 (10 μM) inhibited86Rb+efflux evoked by NS‐1608 in HEK‐293 cells expressing BKCacurrents. A‐272651 concentration‐dependently inhibited BKCacurrents with IC50values of 4.59 μM (Hill coefficient 1.04, measured at +40 mV), and 2.82 μM (Hill coefficient 0.89), respectively, for BKCaα and BKCaαβ1‐mediated currents. Like iberiotoxin, A‐272651 enhanced field stimulated twitch responses in pig detrusor and spontaneous contractions in guinea pig detrusor with EC50values of 4.05±0.05 and 37.95±0.12 μM, respectively. In capsaicin‐sensitive DRG neurons, application of A‐272651 increased action potential firing and prolonged action potential duration.

Conclusions and Implications:

These data demonstrate that A‐272651 modulates smooth muscle contractility and neuronal firing properties. Unlike previously reported peptide BKCablockers, A‐272651 represents one of the first small molecule BKCachannel blockers that could serve as a useful tool for further characterization of BKCachannels in physiological and pathological states.

British Journal of Pharmacology(2007)151, 798–806; doi:10.1038/sj.bjp.0707278
Optimization of open circuit voltage in amorphous silicon solar cells with mixed-phase (amorphous+nanocrystalline) p-type contacts of low nanocrystalline content
Authors: Pearce J. M. , Podraza N. , Collins R. W. , Al-Jassim M. M. , Jones K. M. , Deng J. , Wronski C. R.
Published: June 2007

Both the origins of the high open circuit voltages (VOC) in amorphous silicon solar cells having p layers prepared with very high hydrogen dilution and the physical structure of these optimum p layers remain poorly understood topics, with several studies offering conflicting views. This work attempts to overcome the limitations of previous studies by combining insights available from electronic measurements, real time spectroscopic ellipsometry, atomic force microscopy, and both high-resolution transmission electron microscopy (TEM) and dark field TEM of cross sections of entire solar cells. It is found that solar cells fabricated with p layers having a low volume fraction of nanocrystals embedded in a protocrystalline Si:H matrix possess lower recombination at the i∕p interface than standard cells and deliver a higher VOC. The growth of the p layers follows a thickness evolution in which pure protocrystalline character is observed at the interface to the i layer. However, a low density of nanocrystallites nucleates with increasing thickness. The advantages offered by the protocrystalline character associated with the amorphous phase of the mixed-phase (amorphous+nanocrystalline) p layers prepared with excess H2 dilution account for the improved VOC of the optimum p layers. In this model, the appearance of a low volume fraction of nanocrystals near the top transparent conductor interface is proposed to be incidental to the high VOC.
Categories of holomorphic line bundles on higher dimensional noncommutative complex tori
Authors: Kajiura Hiroshige
Published: June 2007

We construct explicitly noncommutative deformations of categories of holomorphic line bundles over higher dimensional tori. Our basic tools are Heisenberg modules over noncommutative tori and complex∕holomorphic structures on them introduced by Schwarz [“Theta functions on noncommutative tori,” Lett. Math. Phys. 58, 81–90 (2001)]. We obtain differential graded (DG) categories as full subcategories of curved DG categories of Heisenberg modules over the complex noncommutative tori. Also, we present the explicit composition formula of morphisms, which, in fact, depends on the noncommutativity.