bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of supercritical fluid extracts from raw wool by TLC‐FID and GC‐MS
Authors: Domínguez C. , Jover E. , Garde F. , Bayona J. M. , Erra P.
Published: November 2006

Extraction selectivity of whole wool wax from raw wool by using ethanol‐modified carbon dioxide at constant pressure (100 bar) and temperature (60°C) was studied. A kinetic study was carried out to optimize the percentage of ethanol and the extraction time. The modified carbon dioxide was decompressed in ethanol as a collection solvent, leading to the formation of two different fractions as a function of their solubility. Qualitative and quantitative analyses of the lipid classes present in the collected fractions were performed by TLC coupled to an automated FID system (TLC‐FID). Moreover, a detailed structural comparison was carried out between the aliphatic high‐molecular‐mass esters and the steryl ester patterns by means of subambient pressure GC‐MS in both the EI and the ammonia positive Cl modes. Considerable differences in the lipid composition of the two wool wax fractions collected were observed by TLC‐FID and GC‐MS.
Thermal behavior of fat droplets as related to adsorbed milk proteins in complex food emulsions. A DSC study
Authors: Relkin Perla , Ait‐Taleb Amel , Sourdet Stéphanie , Fosseux Pierre‐Yves
Published: November 2006

The thermal behavior of hydrogenated palm kernel oil‐in‐water emulsions, which differed in their milk‐protein composition, was studied in parallel with other characteristic parameters such as the aggregation/coalescence of fat droplets, and the proportion of adsorbed proteins at the oil/water interface. DSC was applied to monitor the crystallization and melting behavior of nonemulsified and emulsified fat samples. Comparison between nonemulsified and emulsified fat samples showed that in emulsified samples the initial temperature of fat crystallization and the temperature of the completion of melting were invariably lower and slightly higher, respectively. Furthermore, in complex food emulsions the supercooling temperature needed to initiate fat crystallization and the variation in its growth rate in the cooling experiment were dependent on the amount and nature of the adsorbed proteins. Our results indicate that the total replacement of milk proteins by whey proteins affected the fat crystallization behavior of emulsified fat droplets, in parallel with changes in their protein surface coverage and in their physical stability against fat droplet agglomeration.
Thermal and rheological properties of Lupinus albus flour
Authors: Xu Jingyuan , Mohamed Abdellatif A.
Published: November 2006

The thermal and rheological properties of lupin flour were investigated by DSC and rheometry. DSC study showed that whole and defatted lupin meal had identical thermal properties, and lupin had the same glass transition as the wheat protein gluten. By measuring the linear rheological properties of a series of concentrations of defatted lupin suspensions, we found that defatted lupin suspensions exhibited strong viscoelastic solid properties, which were to some extent similar to those of gluten. Both storage (G′) and loss (G″) moduli increased dramatically over a narrow range of lupin concentrations. The linear range of the rheological properties of lupin was very small. The stress relaxation studies showed that the lupin suspensions did not relax a decade within a thousand seconds, indicating that the molecules of lupin have strong physical interactions. This research offered new insight into physical properties of lupin and will be useful for further studies on applications for lupin.
Effects of natural antioxidants on iron‐catalyzed lipid oxidation of structured lipid‐based emulsions
Authors: Osborn Hannah T. , Akoh Casimir C.
Published: November 2006

The effects of iron, pH, and natural antioxidants (α‐tocopherol, gallic acid, and quercetin) on oxidation of structured lipid‐based emulsions were evaluated. Ten percent oil‐in‐water emulsions were formulated with a canola oil/caprylic acid structured lipid and stabilized with 0.5% whey protein isolate. The PV, anisidine values, and Totox values of emulsions stored at 50°C were measured over a 15‐d period. Iron significantly (P<0.05) increased lipid oxidation rates compared to control emulsions. Greater iron‐catalyzed lipid oxidation occurred in the pH 3.0 emulsions compared to their pH 7.0 counterparts. Quercetin and gallic acid exhibited significant (P<0.05) prooxidant effects on total oxidation in the pH 3.0 emulsions. Emulsions at pH 7.0 were relatively stable to oxidation throughout the storage period. Because of the ability of some of these natural antioxidants to exhibit prooxidant activity, care should be exercised when adding them to food systems containing transition metals.
Applications of immobilized Thermomyces lanuginosa lipase in interesterification
Authors: Yang Tiankui , Fruekilde Maj‐Britt , Xu Xuebing
Published: November 2006

The aim of this work was to investigate the catalytic functions of a new immobilized Thermomyces lanuginosa lipase in interesterification and to optimize the conditions of interesterification for the production of human milk fat substitutes (HMFS) containing n−3 PUFA by response surface methodology (RSM). Thermomyces lanuginosa lipase had an activity similar to that of immobilized Rhizomucor miehei lipase (Lipozyme RM IM) in the glycerolysis of sunflower oil, but the former had higher activity at a low reaction temperature (5°C). Thermomyces lanuginosa lipase was found to have much lower catalytic activity than Lipozyme RM IM in the acidolysis of sunflower oil with caprylic acid. However, the activity of T. lanuginosa lipase was only slightly lower than that of Lipozyme RM IM in the ester‐ester exchange between tripalmitin (PPP) and the ethyl esters of EPA and DHA (EE). For this reason, the new immobilized T. lanuginosa lipase was used to produce HMFS from PPP by interesterification with EE. The optimization of major parameters was conducted with the assistante molar ratio of 5 (EE/PPP), a lipase load of 20 wt% (on substrates), and a reaction time of 20 h, with acyl incorporation up to 42%. The model generated significantly represented real relationships between the response (incorporation) and reaction parameters.
Development and optimization of cultured goat cream butter
Authors: Rodríguez Alicia , Bunger Andrea , Castro Eduardo , Sousa Isabel , Empis Jose
Published: November 2006

A central composite design 22+star based on response surface methodology was used for development and optimization of a cultured goat cream butter formulation (cultured). The goat milk cream was inoculated with freeze‐dried mesophilic aromatic lactic cultures and showed an increase in acidity and a aromatic lactic cultures and showed an increase in acidity and a decrease in lactose content when the concentration of lactic cultures was increased. An optimized temperature of 28°C was chosen for fast acid production in the goat milk cream. The lactic culture concentration significantly affected flavor, sensory texture, and overall quality, but the fermentation process were an inoculum dosage of 8.8 U/100 L and a fermentation time of 7 h at 28°C. This cultured formulation achieved optimal sensory quality in the attributes appearance, flavor, texture, and overall quality. At refrigerator temperature (4°C) the cultured formulation behaved as a solid and lacked spreadability, whereas it had ideal spreadability at 15°C when the solid fat content (SFC) was around 18.0%. At room temperature (18–25°C) the SFC was between 11 and 8%, respectively.
Antioxidant effect of soy lecithins on vegetable oil stability and their synergism with tocopherols
Authors: Judde Armelle , Villeneuve Pierre , Rossignol‐Castera Anne , Le Guillou Anne
Published: November 2006

The antioxidant effect of lecithins was tested on several oils and fats varying in FA composition and tocopherol content. Standard lecithins, when added at a level of 1% w/w, exhibited a good protective effect against oxidation. This effect was observed to depend on the phospholipid content of the tested lecithins and the FA composition of the tested oils. Better results were obtained with lecithin samples containing high proportions of PC and PE. Indeed, the main antioxidant mechanism of lecithins was due to a synergistic effect between amino‐alcohol phospholipids and γ‐ and δ‐tocopherols. No synergism was observed with α‐tocopherols, especially when the tested oil was rich in linoleic acid. Therefore, the antioxidant protection of lecithins was not effective for sunflower oil. Finally, the use of fractionated or enriched lecithins was not clearly advantageous compared to standard oil lecithins.
Electrospray ionization MS of high M.W. TAG oligomers
Authors: Byrdwell W. Craig , Neff William E.
Published: November 2006

Reported are the on‐line LC/electrospray ionization MS of large, high M.W. oligomers formed from heated triolein, a TAG used as a model for dietary oils. Triolein, the major component of olive oil, canola oil, and other dietary oils, was heated at frying temperature, and the TAG oxidation products were separated using RP‐HPLC coupled to an ion trap mass spectrometer via an electrospray ionization interface. Ammonium formate was added as a sheath liquid to promote ammonium adduct formation. Masses corresponding to ammonium adducts of intact carbon‐linked dimers (m/z 1783–1787), trimers (m/z 2666–2672), and tetramers (m/z 3547–3557) of triolein, with and without additional sites of unsaturation, were observed. Also, dimers, trimers, and tetramers containing one, two, or three additional oxygens, also with and without additional sites of unsaturation, are reported. Based on the formation of some types of triolein dimers, we believe that tristearin might also form dimers, even though it has no readily oxidizable sites of unsaturation. Oxidized tristearin monomers, tristearin dimers, chainaddition products, and chain‐shortened products are observed.
In situ alkaline transesterification: An effective method for the production of fatty acid esters from vegetable oils
Authors: Haas Michael J. , Scott Karen M. , Marmer William N. , Foglia Thomas A.
Published: November 2006

The production of simple alkyl FA esters by direct alkali‐catalyzed in situ transesterification of the acylglycerols (AG) in soybeans was examined. Initial experiments demonstrated that the lipid in commercially produced soy flakes was readily transesterified during agitation at 60°C in sealed containers of alcoholic NaOH. Methyl, ethyl, and isopropyl alcohols readily participated in the reaction, suggesting that the phenomenon is a general one. Statistical experimental design methods and response surface regression analysis were used to optimize reaction conditions, using methanol as alcohol. At 60°C, the highest yields of methyl ester with minimal contamination by FFA and AG were predicted at a molar ratio of methanol/AG/NaOH of 226∶1∶1.6 with an approximately 8‐h incubation. An increase in the amount of methanol, coupled with a reduced alkali concentration, also gave high ester yields with low FFA and AG contamination. The reaction also proceeded well at 23°C (room temperature), giving higher predicted ester yields than at 60°C. At room temperature, maximal esterification was predicted at a molar ratio of 543∶1∶2.0 for methanol/AG/NaOH, again in 8 h. Of the lipid in soy flakes, 95% was removed under such conditions. The amount of FAME recovered after in situ transesterification corresponded to 84% of this solubilized lipid. Given the 95% removal of lipid from the soy flakes and an 84% efficiency of conversion of this solubilized lipid to FAME, one calculates an overall transesterification efficiency of 80%. The FAME fraction contained only 0.72% (mass basis) FFA and no AG. Of the glycerol released by transesterification, 93% was located in the alcoholic ester phase and 75 was on the post‐transesterification flakes.
Chemical composition and physicochemical and hydrogenation characteristics of high‐palmitic acid solin (low‐linolenic acid flaxseed) oil
Authors: Hosseinian F. S. , Rowland G. G. , Bhirud P. R. , Dyck J. H. , Tyler R. T.
Published: November 2006

The physicochemical characteristics and FA compositions were determined for refined‐bleached‐deodorized (RBD) high‐palmitic acid solin (HPS) oil, RBD solin oil, and degummed linseed oil. The predominant FA in HPS oil were palmitic (16.6%), palmitoleic (1.4%), stearic (2.5%), oleic (11.3%), linoleic (63.7%), and linolenic (3.4%). HPS oil was substantially higher in palmitic acid than either solin oil or linseed oil, and similar to solin oil in linolenic acid content. HPS, solin, and linseed oils exhibited similar sterol and tocopherol profiles. The physicochemical characteristics of the three oils (iodine value, saponification value, m.p., density, specific gravity, viscosity, PV, FFA content, color) reflected their FA profiles and degree of refinement. During hydrogenation of HPS oil, the proportion of saturated FA (palmitic and stearic) increased, and that of unsaturated FA (oleic, linoleic, and linolenic) decreased as the iodine value declined. This resulted in an inverse linear relationship between m.p. and iodine value. Hydrogenation also generated trans FA. The proportion of trans FA was inversely related to iodine value in partially hydrogenated samples. Fully hydrogenated HPS oil (i.e., HPS stearine, iodine value <5) was devoid of trans FA.
A continuous process for the glycerolysis of soybean oil
Authors: Noureddini H. , Harkey D. W. , Gutsman M. R.
Published: November 2006

A continuous process for the glycerolysis of soybean oil with pure and crude glycerol, the co‐product from the transesterification of soybean oil, was investigated in a pilot plant. The process was equipped with a static and a high‐shear mixer. The experimental studies explored the effects of variations in mixing intensity, temperature, reactant flow rates, and reactant stoichiometry on the formation of MG and DG. The developed process resulted in high conversion of TG to MG. The most favorable conditions were 230°C, 40 mL/min total flow, 25 min of reaction time, 2.5∶1 molar ratio of glycerol/soybean oil, and 3600 rpm for the reactions involving crude glycerol where the concentrations of MG and DG in the product were about 56 and 36 wt%, respectively. Under similar conditions, glycerolysis of pure glycerol resulted in 58% MG and 33% DG. In general, higher temperatures and mixing intensities favored the conversion of TG to MG and DG. Reaction temperature had a greater influence on the extent of the reaction than mixing. The formation of MG approached equilibrium for nearly all cases under investigation.
Characterization and compositional studies of the oils from some legume cultivars, Phaseolus vulgaris, grown in Southern Africa
Authors: Mabaleha M. B. , Yeboah S. O.
Published: November 2006

Seed oils from six legume cultivars of Phaseolus vulgaris, grown in the Kingdom of Lesotho, were extracted and their physicochemical properties and FA compositions were determined in order to compare their dietary lipids with those in P. vulgaris cultivars grown in other parts of the world. The oil content of the beans was very low, ranging from 1.5 to 2.0% (w/w). The acid values ranged from 11.0 to 19.2 mg KOH/g, whereas a combination of the PV and the p‐anisidine values in Holm's equation gave oxidation values that ranged from 11.0 to 15.0. Thus, considerable enzymatic hydrolysis and oxidation had taken place in the beans during storage. Iodine values ranged from 80.5 to 92.3 (Wijs method), indicating moderate unsaturation in the oils. However, capillary GC analysis, supported by proton NMR analysis of the FAME, gave a total unsaturation range from 79.67 to 84.24%. The dominant FA were α‐linolenic acid (36.47–48.81%) and linoleic acid (20.96–36.10%), with appreciable amounts of palmitic acid (14.33–18.23%). This FA composition pattern is quite similar to the FA distribution reported for low oil‐bearing legume seeds. Thus, notwithstanding the different climatic and soil conditions, the general properties of lipids in the southern African legume cultivars were quite similar to those of lipids in P. vulgaris cultivars grown in other parts of the world. The high content of α‐linolenic acid in the cultivars of P. vulgaris could very likely play a beneficial role in reducing the risk of coronary heart disease among the large populations consuming them in the southern African region.
Hydrolysis of acylglycerols and phospholipids of milled rice surface lipids during storage
Authors: Lam Henry S. , Proctor Andrew
Published: November 2006

The relative contribution of acylglycerols and phospholipids to the lipid hydrolysis in milled rice was investigated during storage at 37°C and 70% RH for 50 d. The MAG, DAG, and lysophospholipid contents of surface lipid were determined by reversed‐phase HPLC. The MAG and DAG content of milled rice increased during storage from 0.06 to 0.18% (w/w milled rice), with the MAG content increasing more than that of the DAG. Lysophosphatidylcholine increased throughout the study from 0.013 to 0.034% (w/w), whereas lysophosphatidylinositol and lysophosphatidylethanolamine contents initially increased from 0.002 to 0.003% and from 0.005 to 0.009% (w/w), respectively, and then stabilized until day 50. The relative percentage of TAG and phospholipids hydrolyzed in milled rice increased rapidly during the first 3 d of storage from 12.3 to 37.6% and 25.0 to 62.5% (w/w), respectively, and steadily increased to 53.1 and 73.8% (w/w) on day 50. A higher percentage (62.5%) of phospholipids was hydrolyzed relative to TAG (37.6%) after 3 d and probably contributed significantly to milled rice lipid hydrolysis during early storage. However, TAG concentration (0.57%, w/w) was much higher relative to phospholipids (0.08%, w/w) in surface lipids, and therefore TAG hydrolysis was the major contributor to FFA development and the quality of stored milled rice.
Oxidation kinetics of β‐carotene in oleic acid solvent with addition of an antioxidant, α‐tocopherol
Authors: Shibasaki‐Kitakawa Naomi , Kato Hideto , Takahashi Atsushi , Yonemoto Toshikuni
Published: November 2006

Oxidation experiments with β‐carotene were performed in oleic acid solvent with addition of an antioxidant, α‐tocopherol. A kinetic model was proposed based on a reaction mechanism consisting of the oxidation of β‐carotene, oleic acid, and α‐tocopherol; the antioxidation reactions of β‐carotene and oleic acid by α‐tocopherol; the cross‐reaction of β‐carotene and oleic acid; and the radical‐exchange reaction of β‐carotene and α‐tocopherol. The model quantitatively described the oxidation behavior of β‐carotene over a wide range of temperatures, oxygen compositions, and initial antioxidant concentrations. The model simulated well the time over which β‐carotene was almost totally consumed under practical storage conditions at room temperature in air.
1H NMR characterization of milk lipids: A comparison between cow and buffalo milk
Authors: Antonietta Brescia Maria , Mazzilli Vincenzo , Sgaramella Angela , Ghelli Stefano , Paolo Fanizzi Francesco , Sacco Antonio
Published: November 2006

Characterization of the lipid fraction of raw cow and buffalo milk samples, collected in different breeding areas in Apulia, a region of southern Italy, were performed by means of 1H NMR. The aim of this work was to establish whether FA composition data obtained by 1H NMR can be used in the differentiation of buffalo and cow milk samples according to species. A complete assignment of the signals present in the spectrum was attempted by COSY, heteronuclear coherence spectra. Quantification of FA was carried out by inserting the integrals of particular peaks in suitable calculations. Multivariate statistical analysis, conducted on the results of the quantification, permitted buffalo and cow milks to be distinguished.
New FTIR method for the determination of FFA in oils
Authors: Al‐Alawi Ahmed , van de Voort Frederick R. , Sedman Jacqueline
Published: November 2006

A rapid, practical, and accurate FTIR method for the determination of FFA in edible oils was developed. Analogous to the AOCS titration procedure, the FTIR FFA determination is effected by an acid/base reaction but directly measures the product formed rather than utilizing an end point based on an electrode potential or color change. A suspension of a weak base, potassium phthalimide (K‐phthal) in 1‐propanol (1‐PrOH), is used to convert the FFA present in oils to their carboxylate salt without causing oil saponification, and differential spectroscopy is used to circumvent matrix effects. Samples are first diluted with 1‐PrOH, then split, with one‐half treated with the K‐phthal reagent and the other half with 1‐PrOH (blank reagent), their spectra collected, and differential spectra obtained to ratio out the invariant spectral contributions from the oil sample. Quantification of the percentage of FFA in the oil, expressed as %oleic acid, based on measurement of the peak height of the ν (COO−) absorption of the FFA salt formed, yielded a calibration with an SE of <0.020% FFA over the range of 0–4%. The method was validated by standard addition and the analysis of Smalley check samples, the results indicating that the analytical performance of the FTIR procedure is as good as or better than that of the standard titrimetric procedure. As structured, the FTIR procedure is a primary method, as calibration is not dependent on reference values provided by another method, and has performance criteria that could lead to its consideration as an instrumental AOCS procedure for FFA determination. The FTIR portion of the analysis is automatable, and a system capable of analyzing ∼60 samples/h was developed that could be of benefit to laboratories that carry out a large number of FFA analyses per day.
Acorn (Quercus spp.) fruit lipids: Saponifiable and unsaponifiable fractions: A detailed study
Authors: León‐Camacho Manuel , Viera‐Alcaide Isabel , Vicario Isabel M.
Published: November 2006

The composition of the oils extracted from the acorn fruit of three species of Mediterranean oaks, Quercus ilex L., Q. suber L., and Q. faginea L., was characterized. Both major and minor components, including FA, TG, sterols, methyl sterols, triterpenic and aliphatic alcohols, tocopherols, and hydrocarbons, were identified by standard methods and MS. High‐resolution GLC and HPLC were used for quantification. The FA profile, together with the equivalent carbon numbers and TG carbon numbers, was compared with data for other edible vegetable oils. Oil yield, expressed as wet weight, was 5% (w/w). Sterol content was remarkable for the three species (8,563–11,420 mg/kg), with β‐sitosterol being the most abundant (80%). Oils were also high in tocopherol, with a wide variation between species (165–456 mg/kg) but with γ‐tocopherol predominating in all three oils (90% of the total tocopherol content). Also, high terpenic alcohol contents were found (1527–2984 mg/kg), with dammaradienol and β‐amyrin being the most abundant (33–60% of the total alcohol content). Bioactive properties and industrial applications of this underutilized native product are also discussed.
Lignans and tocopherols in Indian sesame cultivars
Authors: Hemalatha S. , Ghafoorunissa
Published: November 2006

Lignan (sesamol, sesamin, and sesamolin) profile was determined in different cultivars (botanically identified or market samples) of sesame seeds and commercial oils procured from different parts of India. The wide variation observed in total lignans from 21 sesame seed and 9 commercial oils was attributed to variations in sesamin and sesamolin contents. Lignan content was high (18 g sesamin/kg, 10 g sesamolin/kg) in seasame cultivars obtained from the northeastern states of India. In two of the commercial oils having the Agmark label, the total lignan content was ∼12 g/kg (7.3 g sesamin, 4.7 g sesamolin), 50% of the maximum permissible levels of unsaponifiable matter. In both the seeds and commercial oils, γ‐tocopherol was the only representative of tocopherol isomers identified. Sesamin and sesamolin were isolated and crystallized from high‐lignan cultivars, and their purity was confirmed by HPLC and spectral (UV and fluorescence) analysis.
Comparative evaluation of palm oil color measurement using a prototype palm oil colorimeter
Authors: Tan Yew‐Ai , Kuntom Ainie , Lee Chak Khiam , Low Kum Sang
Published: November 2006

The color of refined palm oil and palm oil products is conventionally measured using the manually operated Lovibond® Tintometer. In the present study, one manual/visual and three automatic colorimeters for the measurement of vegetable oil color were used for color measurements of refined palm oil. All colorimeters used were commercially available instruments except for an automatic palm oil colorimeter developed specifically for the measurement of palm oil color. The color values obtained from all four instruments were compared using the visually obtained readings as reference values. Results showed that all three automatic instruments gave correlation coefficients of greater than 0.9300 for red color measurements. In addition, the Student t‐test showed no difference between the analysis of red color using the visual method and the palm oil colorimeter. This investigation concludes that, although it is extremely difficult to reduce the lack of precision in color measurement of palm oil, a properly designed and calibrated automatic instrument may still be the better choice because reproducibility and repeatability are required in all standard test methods. The palm oil colorimeter offers a ready and relatively inexpensive solution to the problem of color matches based on visual observations.
Continuous production of ethyl esters of grease using an immobilized lipase
Authors: Hsu An‐Fei , Jones Kerby C. , Foglia Thomas A. , Marmer William N.
Published: November 2006

The continous production of ethyl esters of grease using a phyllosilicate sol‐gel immobilized lipase from Burkholderias cepacia (IM BS‐30) as catalyst was investigated. Enzymatic transesterification was carried out in a recirculating packed‐column reactor using IM BS‐30 as the stationary phase and ethanol and restaurant grease as the substrates without solvent. The bioreactor was operated at various temperatures (40–60°C), flow rates (5–50 mL/min), and times (8–48 h) to optimize ester production. Under the optimal operating conditions (flow rate, 30 mL/min; temperature, 50°C; mole ratio of substrates, 4∶1 ethanol/grease; reaction time, 48 h), the ester yields were >96%. The IM BS‐30 could be reused in the reactor for continous ester production. The conversion of grease to ester was monitored by HPLC and GC, whereas free and total glycerol content in the product was determined by GC. Either water‐washing or silica column chromatography reduced the free and total glycerol content of the ethyl ester preparation to acceptable levels.
Friends – of a Kind: America and its Allies in the Second World War Mary E. Glantz, FDR and the Soviet Union: The President's Battles Over Foreign Policy (Lawrence: Kansas University Press, 2005, $34.95). Pp. 253. ISBN 0 7006 1365 X. Steven Merritt Miner, Stalin's Holy War: Religion, Nationalism and Alliance Politics, 1941–1945 (Chapel Hill: University of North Carolina Press, 2003, $55.00). Pp. 407. ISBN 0 8078 2736 3. Mark A. Stoler, Allies in War: Britain and American Against the Axis Powers 1940–1945 (London and New York: Hodder Arnold, 2005, £25.00). Pp. 291. ISBN 0 340 72026 3. David Stone, War Summits: The Meetings that Shaped World War II and the Postwar World (Washington, DC: Potomac Books, 2005, $29.95). Pp. 304. ISBN 1 57488 901 X.
Authors: FOLLY MARTIN H.
Published: November 2006

The Second World War continues to be an attractive subject for scholars and even more so for those writing for a general readership. One of the more traditional areas of focus has been the ‘Big Three’ – the alliance of the United States with Britain and the Soviet Union. Public interest in the three leaders – Churchill, Roosevelt and Stalin – remains high, and their decisions continue to resonate in the post-Cold War era, as demonstrated by continued (and often ahistorical) references to the decisions made at the Yalta Conference. Consequently, while other aspects of Second World War historiography have pushed into new avenues of exploration, that which has looked at the Grand Alliance has followed fairly conventional lines – the new Soviet bloc materials have been trawled to answer old questions and using the frames of reference that developed during the Cold War. This has left much to be said about the nature of the relationship of the United States with its great allies and the dynamics and processes of that alliance, and overlooked full and rounded analysis of the role of that alliance as the instrument of Axis defeat.
Influence of decompression rate on the expansion velocity and expansion style of bubbly fluids
Authors: Namiki Atsuko , Manga Michael
Published: November 2006

The decompression rate of magma is correlated with explosivity of volcanic eruptions. We present a series of decompression experiments in a shock tube apparatus to investigate the effect of decompression rate on the expansion and eruption style of bubbly fluids. We also consider the effects of the pressure change ΔP and initial vesicularity ϕi. As an analogue for magma we use viscoelastic polymer solutions. For fast decompression, we observe fragmentation and rupture of bubble walls only for large ΔP and large ϕi. For slow decompression, however, bubbles maintain spherical shapes, and the bubbly fluid does not fragment, irrespective of ΔP and ϕi. We consider two theoretical estimates for the expansion of bubbles, which we refer to as “equilibrium expansion,” in which the pressures inside and outside the bubbles are assumed to be equal, and “disequilibrium expansion,” in which the enthalpy change caused by the pressure change is converted into kinetic energy. The observed expansion velocity is governed by the slower estimate. For slow decompression, where bubbles expand while maintaining their spherical shape, the measured expansion is well explained by equilibrium expansion. In contrast, for fast decompression, in which we observe the rupture of bubble walls and fragmentation, the expansion follows disequilibrium expansion. We conclude that the disequilibrium estimate is an upper limit velocity for the bubble expansion and fragmentation and the rupture of bubble walls require disequilibrium expansion. The calculated threshold decompression rate for disequilibrium expansion is consistent with the estimated decompression rate for the explosive/effusive transition in natural basaltic eruptions.
Nadir measurements of carbon monoxide distributions by the Tropospheric Emission Spectrometer instrument onboard the Aura Spacecraft: Overview of analysis approach and examples of initial results
Authors: Rinsland Curtis P. , Luo Ming , Logan Jennifer A. , Beer Reinhard , Worden Helen , Kulawik Susan S. , Rider David , Osterman Greg , Gunson Michael , Eldering Annmarie , Goldman Aaron , Shephard Mark , Clough Shepard A. , Rodgers Clive , Lampel Michael , Chiou Linda
Published: November 2006

We provide an overview of the nadir measurements of carbon monoxide (CO) obtained thus far by the Tropospheric Emission Spectrometer (TES). The instrument is a high resolution array Fourier transform spectrometer designed to measure infrared spectral radiances from low Earth orbit. It is one of four instruments successfully launched onboard the Aura platform into a sun synchronous orbit at an altitude of 705 km on July 15, 2004 from Vandenberg Air Force Base, California. Nadir spectra are recorded at 0.06‐cm−1 spectral resolution with a nadir footprint of 5 × 8 km. We describe the TES retrieval approach for the analysis of the nadir measurements, report averaging kernels for typical tropical and polar ocean locations, characterize random and systematic errors for those locations, and describe instrument performance changes in the CO spectral region as a function of time. Sample maps of retrieved CO for the middle and upper troposphere from global surveys during December 2005 and April 2006 highlight the potential of the results for measurement and tracking of global pollution and determining air quality from space.
Influence of biomass burning during recent fluctuations in the slow growth of global tropospheric methane
Authors: Simpson Isobel J. , Rowland F. Sherwood , Meinardi Simone , Blake Donald R.
Published: November 2006

During the past 15 years the annual growth rate of tropospheric methane (CH4) has shown striking changes over 2–3 year periods, varying from +1% yr−1 to slightly negative values (−0.2% yr−1). These fluctuations are superimposed on an overall slowdown of the CH4 growth rate since the 1980s. Here we use our complementary measurement of other compounds (ethane, tetrachloroethene) to confirm the influence of biomass burning on large global CH4 pulses in 1998 and 2002–2003. Methane growth rate fluctuations also track ENSO indices, most likely via the influence of ENSO activity on large‐scale biomass burning. We also report the seventh year of near‐zero growth of global CH4 levels (Dec. 1998–Dec. 2005). The global CH4 mixing ratio was 1772 ± 1 ppbv in 2005, and CH4 increases of 118–376 ppbv between 2000–2020 (ten scenarios in the 2001 IPCC report, to levels around 1900+ ppbv by 2020, now appear quite unlikely.
Arecibo observations of ionospheric perturbations associated with the passage of Tropical Storm Odette
Authors: Bishop R. L. , Aponte N. , Earle G. D. , Sulzer M. , Larsen M. F. , Peng G. S.
Published: November 2006

A suite of instruments including incoherent scatter radar, ionosonde, and a satellite‐bourne GPS receiver observed the ionosphere immediately following the passage of a tropical storm. Tropical Storm Odette formed on 4 December 2003 and proceeded northeasterly over the next 4 days, passing within 600 km of the Arecibo Observatory (AO). On the night of 7–8 December AO measured F region plasma densities and velocities nearly coincident with the storm. Large velocity variations, 10–80 m/s, are evident in the plasma drift components. The variations appear wave‐like with an average period of 90 min at 367 km. Zonal drifts were observed with magnitudes significantly greater than commonly observed for similar geomagnetic conditions. The Ramey ionosonde observed intense midlatitude spread F on the night following the closest passage of the storm. GPS occultations within the storm path showed an increase in gravity wave activity and F region scintillation. Combining the local increase in gravity wave activity with the large drift variations and dominant meridional electric field observed immediately following the storm's traversal of the flux tube coincident with the AO observing volume provide insight into coupling between mesoscale weather systems and the ionosphere.
Shear flow effects at the onset of equatorial spread F
Authors: Hysell D. L. , Larsen M. F. , Swenson C. M. , Wheeler T. F.
Published: November 2006

Experiments were conducted during the NASA Equatorial Ionospheric Study (EQUIS) II sounding rocket campaign on Kwajalein Atoll to investigate the dynamics and stability of the postsunset equatorial F region ionosphere prior to the onset of equatorial spread F (ESF). Experiments took place on 7 and 15 August 2004, each composed of the launch of an instrumented and two chemical release sounding rockets. The instrumented rockets measured plasma number density, vector electric fields, and other parameters to an apogee of about 450 km. The chemical release rockets yielded lower thermospheric wind profile measurements. The Altair radar was used to monitor coherent and incoherent scatter in UHF and VHF bands. In both experiments, large‐scale waves preceded the emergence of ESF depletions and irregularities. We propose that the large‐scale waves were produced by a collisional shear instability. A three‐dimensional electrodynamic model is constructed that can reproduce the shear flow observed by the rockets. On the basis of the model, we calculate the linear growth rate for the collisional shear instability and show that it can compete with the generalized Rayleigh Taylor instability. A scenario where the former generates the large‐scale waves and initiates the latter is discussed.
Transient wind‐driven upwelling in a submarine canyon: A process‐oriented modeling study
Authors: Kämpf Jochen
Published: November 2006

A hydrodynamic model is employed to study flow near a submarine canyon during conditions of upwelling‐favorable coastal winds. Findings reveal that up‐canyon flow is the rapid geostrophic adjustment to barotropic pressure gradients establishing across the canyon. Stratification leads to the formation of a cyclonic eddy within the canyon, trapping neutrally buoyant matter, and limits the upwelling depth only when a strong seasonal pycnocline is located below shelf‐break depth. Typical speeds of up‐canyon flow are 10–30 cm/s. Constrained by the timescale of synoptic weather patterns (∼5 days), only stronger events (high upwelling index) can move slope water from a depth >300 m onto the continental shelf and close toward the coast, where it can be lifted into surface layers during a subsequent upwelling event.
Exploring global patterns of net primary production carbon supply and demand using satellite observations and statistical data
Authors: Imhoff Marc L. , Bounoua Lahouari
Published: November 2006

A unique combination of satellite and socioeconomic data were used to explore the relationship between human consumption and the carbon cycle. The amount of Earth's net primary production (NPP) required to support human activities is a powerful measure of the aggregate impact on the biosphere and indicator of societal vulnerability to climate change. Biophysical models were applied to consumption data to estimate the annual amount of Earth's terrestrial net primary production humans require for food, fiber (including fabrication) and fuel using the same modeling architecture as satellite‐supported NPP measurements. The amount of NPP required was calculated on a per capita basis and projected onto a global map of population to create a spatially explicit map of NPP‐carbon “demand” in units of elemental carbon. NPP demand was compared to a map of Earth's average annual net primary production or “supply” created using 17 years (1982–1998) of AVHRR vegetation index to produce a geographically accurate balance sheet of NPP‐carbon “supply” and “demand” for the globe. Globally, humans consume 20% of Earth's total net primary production on land. Regionally, the NPP‐carbon balance percentage varies from 6% to over 70% and locally from near 0% to over 30,000% in major urban areas. Scenarios modeling the impact of per capita consumption, population growth, and technology suggest that NPP demand is likely to increase substantially in the next 40 years despite better harvesting and processing efficiencies.
Evaluation of ISLSCP Initiative II FASIR and GIMMS NDVI products and implications for carbon cycle science
Authors: Hall Forrest , Masek Jeffrey G. , Collatz G. James
Published: November 2006

Integration of NDVI data into ecological and biogeochemical modeling has placed more stringent requirements on the accuracy and stability of the measurement. We compare two recent AVHRR NDVI data sets included as part of ISLSCP Initiative II: (1) the Fourier‐Adjusted, Sensor and Solar zenith angle corrected, Interpolated, Reconstructed (FASIR) monthly time series and (2) the Global Inventory Modeling and Mapping Studies (GIMMS) monthly time series. Although both started with nearly identical composited AVHRR GAC data sets, each data set has been processed differently to reduce sensor, atmospheric, and illumination effects that vary over time. We find that the resulting absolute NDVI data records differ substantially and consistently for large parts of the globe. These differences also propagate into the NDVI anomaly record (e.g., deviations from monthly or annual means) particularly in the 1984–1985, 1994 periods. To assess the effect of these differences on predictions of land surface CO2 fluxes, the fraction of absorbed photosynthetically active radiation (fPAR) was calculated from each record, and used to drive a biogeochemical model (CASA). On a global basis, calculated net ecosystem exchange shows large variability inherited from the NDVI records. However, these variations do not match global CO2 fluxes derived from atmospheric inversion of CO2 concentration measurements. We conclude that other processes (burning, physiologic response to stress) are likely responsible for major anomalies in the observed global land net carbon fluxes to the atmosphere during the period 1982–1998.
Neuroprotection in Ischemic Mouse Brain Induced by Stem Cell-Derived Brain Implants
Authors: Pignataro Giuseppe , Studer Francesca E , Wilz Andrew , Simon Roger P , Boison Detlev
Published: November 2006

Protective mechanisms of the brain may reduce the extent of injury after focal cerebral ischemia. Here, we explored in a mouse model of focal cerebral ischemia potential synergistic neuroprotective effects of two mediators of neuroprotection: (i) neuronal or glial precursor cells and (ii) the inhibitory neuromodulator adenosine. Embryonic stem (ES) cells, engineered to release adenosine by biallelic disruption of the adenosine kinase gene, and respective wild-type cells were induced to differentiate into either neural or glial precursor cells and were injected into the striatum of mice 1 week before middle cerebral artery occlusion. All stem cell-derived graft recipients were characterized by a significant reduction in infarct volume, an effect that was augmented by the release of adenosine. Neuroprotection was strongest in adenosine-releasing glial precursor cell recipients, which were characterized by an 85% reduction of the infarct area. Graft-mediated neuroprotection correlated with a significant improvement of general and focal neurologic scores. Histologic analysis before and after ischemia revealed clusters of implanted cells within the striatum of all treated mice. We conclude that ES cell derived adenosine-releasing brain implants provide neuroprotection by synergism of endogenous precursor cell-mediated effects and paracrine adenosine release.
Microcontroller-based wavemeter using compression locking of an internal mirror reference laser
Authors: Ugray M. , Atfield J. E. , McCarthy T. G. , Shiell R. C.
Published: November 2006

We show that a highly reliable and compact wavemeter incorporating a reference laser and traveling Michelson interferometer can be controlled, and the unknown wavelength determined, using readily programmable microcontroller circuits. These chips, powered by a 5V supply, each replace a network of many electronic components and enable equipment to be built and debugged in a very short time, to occupy a very small footprint and to be easily modified. With this wavemeter we demonstrate the ease with which programmable microcontrollers can play an important role in a physics research laboratory. We also present, for the first time, the stabilization of an internal mirror HeNe reference laser through direct compression of the glass tube, resulting in stable, mode power balanced operation for a period of more than 8h. This novel stabilization scheme enables a much higher bandwidth and shorter settling time of the servo system than previous heater-based approaches by overcoming technical problems associated with the thermal conductivity of the heater/laser system. The accuracy of the wavemeter has been confirmed by measuring the wavelength of a tunable diode laser as it was scanned across the D1 and D2 lines of Li7, detected through optogalvanic spectroscopy.
A Monte Carlo simulation study of branched polymers
Authors: Yethiraj Arun
Published: November 2006

Monte Carlo simulations are presented for the static properties of highly branched polymer molecules. The molecules consist of a semiflexible backbone of hard-sphere monomers with semiflexible side chains, also composed of hard-sphere monomers, attached to either every backbone bead or every other backbone bead. The conformational properties and structure factor of this model are investigated as a function of the stiffness of the backbone and side chains. The average conformations of the side chains are similar to self-avoiding random walks. The simulations show that there is a stiffening of the backbone as degree of crowding is increased, for example, if the branch spacing is decreased or side chain length is increased. The persistence length of the backbone is relatively insensitive to the stiffness of the side chains over the range investigated. The simulations reproduce most of the qualitative features of the structure factor observed in experiment, although the magnitude of the stiffening of the backbone is smaller than in experiment.
Study on interfacial strain behavior of functional oxide heterostructures
Authors: Zhu J. , Wei X. H. , Zhang Y. , Li Y. R.
Published: November 2006

Oxide films of BaTiO3 and MgO were deposited on SrTiO3 single crystal substrates by laser molecular beam epitaxy. Reflection high-energy electron diffraction was performed in situ to investigate the change of growth mode and the lattice relaxation. Due to the different mismatches between epitaxial oxide films and substrates, two kinds of strain relaxation behavior during the growth process can be observed. For the BaTiO3∕SrTiO3 system with the small mismatch of 2.18%, the coherent epitaxial growth can be maintained within the critical thickness. The experimental data were well in accord with the elastic strain theory in the small mismatch system. The coherent epitaxial growth is crucial to fabricate the functional oxide superlattice. However, strained island can form at the initial period to release strain energy in the case of MgO∕SrTiO3 system with the large mismatch of 7.8%. It provides a useful practical method to realize self-organized nanostructures by introducing the moderate strain at interface. Our systematic study on the interface strain of functional oxide heteroepitaxial growth could give an instructive method to realize different heterostructures, e.g., superlattice and nanostructures.
On one-dimensional self-assembly of surfactant-coated nanoparticles
Authors: Wang Jee-Ching , Neogi P. , Forciniti Daniel
Published: November 2006

Nanometer-sized metal and semiconductor particles possess novel properties. To fully realize their potential, these nanoparticles need to be fabricated into ordered arrays or predesigned structures. A promising nanoparticle fabrication method is coupled surface passivation and self-assembly of surfactant-coated nanoparticles. Due to the empirical procedure and partially satisfactory results, this method still represents a major challenge to date and its refinement can benefit from fundamental understanding. Existing evidences suggest that the self-assembly of surfactant-coated nanoparticles is induced by surfactant-modified interparticle interactions and follows an intrinsic road map such that short one-dimensional (1D) chain arrays of nanoparticles occur first as a stable intermediate before further assembly takes place to form higher dimensional close-packed superlattices. Here we report a study employing fundamental analyses and Brownian dynamics simulations to elucidate the underlying pair interaction potential that drives the nanoparticle self-assembly via 1D arrays. We find that a pair potential which has a longer-ranged repulsion and reflects the effects of surfactant chain interdigitation on the dynamics is effective in producing and stabilizing nanoparticle chain arrays. The resultant potential energy surface is isotropic for dispersed nanoparticles but becomes anisotropic to favor the growth of linear chain arrays when self-assembly starts.