bluuebunny/crossref_metadata_2025 huggingface dataset:
Detergency of used motor oil from cotton and polyester fabrics
Authors: Chi Yong‐Seung , Obendorf S. Kay
Published: November 2006

A study was conducted to identity factors contributing to the difficult removal of used motor oil from textile materials by detergency. Infrared spectroscopy and gel permeation chromatography of used motor oil showed that the oil was a saturated aliphatic hydrocarbon with molecular weight around 950. X‐ray analysis revealed that particulates present in the used motor oil contained S, Mg, Al, Si, K, Ca, Fe, Ni, Cu, and Zn. Used motor oil was distributed throughout the cotton fibers with similar concentration of oil in the lumen, secondary wall, and surface crenulation. Higher relative concentrations of used motor oil were observed in the secondary wall of the fiber than has been reported for human sebum. No oil was found in the interior of polyester fibers although high concentrations of oil were detected in the interfiber spaces and on the fiber surfaces of polyester fibers. Dispersant additives of motor oil are though to enhance penetration into the cotton structure and wicking over the polyester fibers, making the nonpolar used motor oil very difficult to remove by detergency.
α‐tocopherol affects the urinary and biliary excretion of 2,7,8‐trimethyl‐2(2′‐carboxyethyl)‐6‐hydroxychroman, γ‐tocopherol metabolite, in rats
Authors: Kiyose Chikako , Saito Hisako , Kaneko Kazuyo , Hamamura Kimio , Tomioka Mitsugu , Ueda Tadahiko , Igarashi Osamu
Published: November 2006

In this study, we investigated a change in the excretory content of 2,7,8‐trimethyl‐2(2′‐carboxyethyl)‐6‐hydroxychroman (γ‐CEHC), a γ‐tocopherol (γ‐Toc) metabolite, in rat urine and bile by using a new high‐performance liquid chromatography‐elelectrochemical detection (HPLC‐ECD) method. In this determination, CEHC [α‐ and γ‐CEHC, where α‐CEHC‐2,5,7,8‐tetramethyl‐2(2′‐carboxyethyl)‐6‐hydroxychioman] in the biological specimens were treated with 3 N methanolic HCl to hydrolyze conjugates and to promote esterification. The methylated samples were extracted by n‐hexane/water (1∶2). The analyses of the methyl esters of α‐CEHC and γ‐CEHC were performed by an HPLC‐ECD using an ODS‐3 column at 35°C. The mobile phase was acetonitrile/water (45∶55, vol/vol) containing 50 mM sodium perchlorate. After rat urine and bile samples, respectively, were methylated as described above, methylated biliary metabolites were identified by liquid chromatography mass spectrometry as methyl esters of γ‐CEHC. Furthermore, we examined the differences in the excretion of γ‐CEHC between rat urine and bile after an oral administration of γ‐Toc or α‐ +γ‐Toc by the above HPLC method. In the γ‐Toc group, each vitamin E‐deficient rat was given 0.5 mL of a stripped corn oil preparation containing 10 mg of γ‐Toc. In the α‐ +γ‐Toc group, the rat was given 10 mg of α‐Toc and 10 mg of γ‐Toc. The content of γ‐CEHC in rat urine from the α‐ +γ‐Toc group was increased more in comparison to the γ‐Toc group at 18–36 h after oral administration. Moreover, the content of γ‐CEHC in rat bile in the α‐ +γ‐Toc group was increased more in comparison to the γ‐Toc group at 6–18 h after oral administration. Therefore, we have suggested that γ‐CEHC was shifted mainly to urinary excretion after γ‐CEHC had been excreted into the bile. Furthermore, we assume that α‐Toc may affect the metabolism of γ‐Toc to γ‐CEHC in the body.
Temperature‐enhanced alumina HPLC method for the analysis of wax esters, sterol esters, and methyl esters
Authors: Moreau Robert A. , Kohout Karen , Singh Vijay
Published: November 2006

Previous attempts at separating nonpolar lipid esters (including wax esters, sterol esters, and methyl esters) have achieved only limited success. Among the several normal‐phase methods tested, a single recent report of a method employing an alumina column at 30°C with a binary gradient system was the most promising. In the current study, modification of the alumina method by increasing the column temperature to 75°C improved the separation of standards of wax esters and sterol esters. Elevated column temperature also enhanced the separation of FAME with differing degrees of unsaturation. Evidence was also presented to indicate that the method similarly separated phytosterol esters, based on their levels of unsaturation. With the increased interest in phytosterol‐ and phytostanol esterenriched functional foods, this method should provide a technique to characterize and compare these products.
Synthesis of fluorinated analogs of myristic acid as potential inhibitors of egyptian armyworm (Spodoptera littorialis) Δ11 desaturasedesaturase
Authors: Abad José‐Luis , Villorbina Gemma , Fabriàs Gemma , Camps Francisco
Published: November 2006

To study the activity of the different desaturases present in the pheromone biosynthetic pathway of the Egyptian armyworm, Spodoptera littoralis, we prepared a series of mono‐and gem‐difluorinated analogs of myristic acid with halogen substitution at the C8–C11 positions of the aliphatic chain via specifically positioned dithiane precursors. Thus, transformation of dithianes by treatment with N‐bromosuccinimide in the presence of H2O followed by reduction with LiAIH4 afforded the appropriate alcohols, which reacted with diethylaminosulfur trifluoride to give rise to the corresponding monofluoroderivative intermediates. Alternatively, the introduction of the gem‐difluoro functionality was carried out by reaction of the appropriate dithiane intermediate with 1,3‐dibromo‐5,5‐dimethylhydantoin in the presence of HF/pyridine. The activity of these fluorinated FA as substrates and inhibitors of the desaturases involved in the biosynthesis of the sex pheromonal blend of S. littoralis has been studied. In this case, 11‐fluorotetradecanoic acid elicited a moderate inhibitory activity of Δ11 desaturase.
Daphnia magna can tolerate short‐term starvation without major changes in lipid metabolism
Authors: Bychek E. A. , Dobson G. A. , Harwood J. L. , Guschina I. A.
Published: November 2006

Daphnia magna is a common crustacean that is adapted to brief speels of fasting. Lipids are naturally a major component of their diet and are stored as energy reserves. However, there has been some controversy in the literature on the extent to which dietary lipids are used directly for complex lipid formation in Daphnia. We examined lipid metabolism in D. magna by labeling the animals using [1‐14C]acetate and then followed the turnover of radiolabeled lipids during a pulse chase. Daphnia were either fed or maintained without food during the chase period. The decrease in radioactivity during the chase was relatively unaffected by feeding, although there were some differences in the distribution of radioactivity between lipid classes or individual FA. The polar lipids, which were four times better labeled than nonpolar lipids, contained the most radioactivity in the zwitterionic phosphoglycerides, PE and PC. Under the experimental conditions, the turnover of the polar membrane lipids was unaffected by feeding. Within nonpolar lipids, TAG accounted for up to about 80% of the label, followed by DAG. Overall, our data show that D. magna is capable of high rates of lipid radiolabeling de novo and, in addition, is able to use—and indeed may be dependent on—some dietary components such as the PUFA linoleate and α‐linolenate. The results also clearly show that Daphnia is able to tolerate brief spells of fasting (24 h) with very little change to its lipid metabolism.
Dietary phospholipids are more efficient than neutral lipids for long‐chain polyunsaturated fatty acid supply in European sea bass Dicentrarchus labrax larval development
Authors: Gisbert E. , Villeneuve L. , Zambonino‐Infante J. L. , Quazuguel P. , Cahu C. L.
Published: November 2006

We evaluated the effects of dietary lipid class (phospholipid vs. neutral lipid) and level of n−3 long‐chain PUFA (LC‐PUFA) on the growth, digestive enzymatic activity, and histological organization of the intestine and liver in European sea bass larvae. Fish were fed from the onset of exogenous feeding at 7 to 37 d post‐hatch with five isoproteic and isolipidic compound diets with different levels of EPA and DHA. Diet names indicated the percentage of EPA and DHA contained in the phospholipids (PL) and neutral lipids (NL), as follows: PL5, PL3, PL1, NL1, and NL3. Histological observations showed different patterns of lipid absorption and accumulation in the intestinal mucosa depending on the level and nature of the dietary lipid fraction. Fish fed high levels of neutral lipids (11%, NL3 diet: 2.6% of EPA+DHA in the NL fraction) showed large intracellular and intercellular lipid deposits in the anterior intestine, but no such lipid accumulation was detected when larvae were fed with low and moderate levels of EPA and DHA in the phospholipid and neutral lipid fractions of the diet (PL and NL1 diets). PL were preferentially absorbed in the postvalvular intestine, and the accumulation of marine PL was inversely correlated to their dietary level. The postvalvular intestinal mucosa and liver showed signs of steatosis; large lipid vacuoles were observed in this region of the intestine and in the liver and were inversely correlated with the level of dietary neutral lipids. The best results in terms of growth, survival, and development (maturation of the digestive system and histological organization of the liver and intestinal mucosa) were obtained in the group fed with 2.3% of EPA and DHA in the PL fraction of the diet (PL3 diet), revealing that European sea bass larvae use the LC‐PUFa contained in the PL fraction more efficiently than those from the NL fraction of the diet.
Recent advances in the biochemistry and clinical relevance of the isoprostane pathway
Authors: Musiek Erik S. , Yin Huiyong , Milne Ginger L. , Morrow Jason D.
Published: November 2006

Isoprostanes (IsoPs), lipid peroxidation products formed via the free radical‐mediated oxidation of arachidonic acid, have become the “gold standard” biomarker of oxidative stress in vivo over the past 15 yr. Significant advances have been made in understanding this important pathway of lipid peroxidation. Recent studies from our laboratory are discussed that have provided insights into the mechanism of formation and regioisomeric distribution of these compounds and that have identified novel products of the IsoP pathway such as cyclized dioxolane IsoPs, IsoP‐derived racemic prostaglandins, and reactive cyclopentenone IsoP, the latter of which possess potent biological actions. Furthermore, new independent studies have demonstrated that IsoPs are the most reliable available marker of lipid peroxidation in vivo, and recent work examining IsoP formation has provided valuable infromation about the pathogenesis of numerous human diseases. Thus, the complexity of the IsoP pathway has expanded, providing novel insights into mechanisms of lipid peroxidation in vivo and allowing investigators to explore the role of oxidative stress in human disease.
Fatty acids in must prepared from 11 grapes grown in Japan: Comparison with wine and effect on fatty acid ethyl ester formation
Authors: Yunoki Keita , Yasui Yoshiro , Hirose Shuji , Ohnishi Masao
Published: November 2006

FA components of 11 mustsmade from grape cultivars grown for making red wine in various regions of Japan and of wines made from the musts were compared to elucidate variety‐dependent characteristics and to clarify their effect on FA ethyl ester (FAEE) formation in wine. Sixteen FA with carbon chain lengths from 12 to 26 were detected in all musts, with palmitic, linoleic, and linolenic acids generally predominating. Higher levels of linoleic acid were found in musts from a cold region (Hokkaido), and higher levels of oleic acid occurred in musts from a warm region (Honshu). Moreover, the unsaturation indexes (1.31–1.56) of five grape musts from the cold region showed significant differences among varieties, corresponding to the grapevines’ degree of cryotolerance. The FA levels (610–6,610 nmol/100 mL) of all wines were extremely low (1.2–12.8%) compared with those of must, but the FA compositions were similar to those of must. Additionally, significant amounts of FAEE, possibly derived from yeast activity, were found in wines by using a solid‐phase extraction method. The amounts of FAEE in wine significantly differed among samples (245–904 nmol/100 mL) and were inversely correlated with the percentage of linoleic acid in musts (R=−0.883). Thus, higher linoleic acid levels in must may be related to lower FAEE formation by yeast.
A pathway for biosynthesis of divinyl ether fatty acids in green leaves
Authors: Hamberg Mats
Published: November 2006

[1‐14C]α‐Linolenic acid was incubated with a particulate fraction of homogenate of leaves of the meadow buttercup (Ranunculus acris L.). The main product was a divinyl ether fatty acid, which was identified as 12‐[1′(Z),3′(Z)‐hexadienyloxy]‐9(Z), 11(E)‐dodecadienoic acid. Addition of glutathione peroxidase and reduced glutathione to incubations of α‐linolenic acid almost completely suppressed formation of the divinyl ether acid and resulted in the appearance of 13(S)‐hydroxy‐9(Z), 11(E), 15(Z)‐octadecatrienoic acid as the main product. This result, together with the finding that 13(S)‐hydroperoxy‐9(Z), 11(E), 15(Z)‐octadecatrienoic acid served as an efficient precursor of the divinyl ether fatty acid, indicated that divinyl ether biosynthesis in leaves of R. acris occurred by a two‐step pathway involving an ω6‐lipoxygenase and a divinyl ether synthase. Incubations of isomeric hydroperoxides derived from α‐linolenic and linoleic acids with the enzyme preparation from R. acris showed that 13(S)‐hydroperoxy‐9(Z), 11(E)‐octadecadienoic acid was transformed into the divinyl ether 12‐[1′(Z)‐hexenyloxy]‐9(Z), 11(E)‐dodecadienoic acid. In contrast, neither the 9(S)‐hydroperoxides of linoleic or α‐linolenic acids nor the 13(R)‐hydroperoxide of α‐linolenic acid served as precursors of divinyl ethers.
Metabolism of dietary α‐linolenic acid vs. eicosapentaenoic acid in rat immune cell phospholipids during endotoxemia
Authors: Palombo John D. , DeMichele Stephen J. , Boyce Patricia J. , Noursalehi Mojtaba , Armour Forse R. , Bistrian Bruce R.
Published: November 2006

Short‐term (i.e., 3 d) continuous enteral feeding of diets containing eicosapentaenoic (EPA) and γ‐linolenic (GLA) polyunsaturated fatty acids (PUFA) to endotoxemic rats reduces the levels of arachidonic acid (AA) and linoleic acid (LA) in alveolar macrophage (AM) and liver Kupffer and endothelial (K&E) cell phospholipids with attendant decreases in prostaglandin formation by these cells in vitro. Diets that contain α‐linolenic acid (LNA) as a substrate for endogenous formation of EPA may not be as effective in facilitating these immune cell modifications given the limited activity of Δ6 desaturase. In the present study we compared the effectiveness of an LNA‐enriched diet vs. an (EPA+GLA)‐enriched diet to displace phospholipid AA from AM and liver K&E cells in vivo in endotoxemic rats fed enterally for 3 or 6 d. We determined the fatty acid composition of AM and K&E cell phospholipids by gas chromatography. We found that AM and K&E cells from rats that had received the EPA+GLA diet for 3 d had significantly (P<0.001) higher mole percentage of EPA and the GLA metabolite, dihomoGLA, than corresponding cells from rats given the LNA diet or a control diet enriched with LA. Rats given the LNA diet had relatively low levels of stearidonic acid, EPA and other n−3 PUFA, while rats given the LA diet had low levels of GLA and dihomoGLA. We conclude that diets enriched with LNA or LA may not be as effective as those enriched with FPA+GLA for purposes of fostering incorporation of EPA or dihomoGLA into and displacement of AA from macrophage phospholipids under pathophysiologic conditions commonly found in acutely septic patients.
Distinct mechanisms underlie distinct polyphenol‐induced neuroprotection
Authors: Yazawa Keiko , Kihara Takeshi , Shen Huilian , Shimmyo Yoshiari , Niidome Tetsuhiro , Sugimoto Hachiro
Published: November 2006

Glutamate excitotoxicity is mediated by intracellular Ca2+ overload, caspase‐3 activation, and ROS generation. Here, we show that curcumin, tannic acid (TA) and (+)‐catechin hydrate (CA) all inhibited glutamate‐induced excitotoxicity. Curcumin inhibited PKC activity, and subsequent phosphorylation of NR1 of the NMDA receptor. As a result, glutamate‐mediated Ca2+ influx was reduced. TA attenuated glutamate‐mediated Ca2+ influx only when simultaneously administered, directly interfering with Ca2+. Both curcumin and TA inhibited glutamate‐induced caspase‐3 activation. Although Ca2+ influx was not attenuated by CA, caspase‐3 was reduced by direct inhibition of the enzyme. All polyphenols reduced glutamate‐induced generation of ROS.
The 1923 Kanto earthquake reevaluated using a newly augmented geodetic data set
Authors: Nyst M. , Nishimura T. , Pollitz F. F. , Thatcher W.
Published: November 2006

This study revisits the mechanism of the 1923 Ms = 7.9 Kanto earthquake in Japan. We derive a new source model and use it to assess quantitative and qualitative aspects of the accommodation of plate motion in the Kanto region. We use a new geodetic data set that consists of displacements from leveling and angle changes from triangulation measurements obtained in surveys between 1883 and 1927. Two unique aspects of our analysis are the inclusion of a large number of second‐order triangulation measurements and the application of a correction to remove interseismic deformation. The geometry of the fault planes is adopted from a recent seismic reflection study of the Kanto region. We evaluate the minimum complexity necessary in the model to fit the data optimally. Our final uniform‐slip elastic dislocation model consists of two adjacent ≈20° dipping low‐angle planes accommodating reverse dextral slip of 6.0 m on the larger, eastern plane and 9.5 m on the smaller, western plane with azimuths of 163° and 121°, respectively. The earthquake was located in the Sagami trough, where the Philippine Sea plate subducts under Honshu. Compared to the highly oblique angle of plate convergence, the coseismic slip on the large fault plane has a more orthogonal orientation to the strike of the plate boundary, suggesting that slip partitioning plays a role in accommodation of plate motion. What other structure is involved in the partitioning is unclear. Uplift records of marine coastal terraces in Sagami Bay document 7500 years of earthquake activity and predict average recurrence intervals of 400 years for events with vertical displacement profiles similar to those of the 1923 earthquake. This means that the average slip deficit per recurrence interval is ∼50% of the relative plate convergence. These findings of plate motion partitioning and slip deficit lead us to suggest that instead of a simple recurrence model with characteristic earthquakes, additional mechanisms are necessary to describe the accommodation of deformation in the Kanto region. So far, obvious candidates for these alternative mechanisms have not been discovered.
Seismic velocity structure of the rifted margin of the eastern Grand Banks of Newfoundland, Canada
Authors: Van Avendonk Harm J. A. , Holbrook W. Steven , Nunes Gregory T. , Shillington Donna J. , Tucholke Brian E. , Louden Keith E. , Larsen Hans Christian , Hopper John R.
Published: November 2006

We present a compressional seismic velocity profile of the crust of the eastern margin of the Grand Banks of Newfoundland, Canada. This velocity model was obtained by a tomographic inversion of wide‐angle data recorded on a linear array of 24 ocean bottom seismometers (OBSs). At the landward side, we imaged a crustal thickness of 27 km in Flemish Pass and beneath Beothuk Knoll, which is thinner than the 35‐km‐thick crust of the central Grand Banks. We therefore assume that the eastern rim of the Grand Banks stretched uniformly by 25%. Farther seaward, the continental crust tapers rapidly beneath the continental slope to ∼6 km thickness. In the distal margin we find a 60‐km‐wide zone with seismic velocities between 5.0 and 6.5 km s−1 that thins to the southeast from 6 to 2 km, which we interpret as highly extended continental crust. Contrary to other seismic studies of the margins of the Grand Banks, we find seismic velocities of 8 km s−1 and higher beneath this thin crustal layer in the continent‐ocean transition. We conclude that mantle was locally emplaced at shallow levels without significant hydration from seawater or serpentinized mantle was removed along a décollement in the final stages of continental rifting. The outer edge of highly extended continental crust borders a 25‐km‐wide zone where seismic velocities increase gradually from 6.3 km s−1 just below the top of acoustic basement to 7.7 km s−1 at 5 km below basement. We interpret this area as a relatively narrow zone of exhumed and serpentinized continental mantle. Seaward, we imaged a thin and laterally heterogeneous layer with a seismic velocity that increases sharply from 5.0 km s−1 in basement ridges to 7.0 km s−1 at its base, overlying mantle velocities between 7.8 and 8.2 km s−1. We interpret this area as unroofed mantle and very thin oceanic crust that formed at an incipient, magma‐starved, ultraslow spreading ridge. A comparison of the conjugate rifted margins of the eastern Grand Banks and the Iberia Abyssal Plain show that they exhibit a similar seaward progression from continental crust to mantle to oceanic crust. This indicates that before continental breakup, rifting exhumed progressively deeper sections of the continental lithosphere on both conjugate margins. A comparison between the continent‐ocean transition of the Grand Banks and Flemish Cap shows that the final phase of continental rifting and the formation of the first oceanic crust required more time at the Grand Banks margin than at the southeastern margin of Flemish Cap.
Mantle transition zone structure and upper mantle S velocity variations beneath Ethiopia: Evidence for a broad, deep‐seated thermal anomaly
Authors: Benoit Margaret H. , Nyblade Andrew A. , Owens Thomas J. , Stuart Graham
Published: November 2006

Ethiopia has been subjected to widespread Cenozoic volcanism, rifting, and uplift associated with the Afar hot spot. The hot spot tectonism has been attributed to one or more thermal upwellings in the mantle, for example, starting thermal plumes and superplumes. We investigate the origin of the hot spot by imaging the S wave velocity structure of the upper mantle beneath Ethiopia using travel time tomography and by examining relief on transition zone discontinuities using receiver function stacks. The tomographic images reveal an elongated low‐velocity region that is wide (>500 km) and extends deep into the upper mantle (>400 km). The anomaly is aligned with the Afar Depression and Main Ethiopian Rift in the uppermost mantle, but its center shifts westward with depth. The 410 km discontinuity is not well imaged, but the 660 km discontinuity is shallower than normal by ∼20–30 km beneath most of Ethiopia, but it is at a normal depth beneath Djibouti and the northwestern edge of the Ethiopian Plateau. The tomographic results combined with a shallow 660 km discontinuity indicate that upper mantle temperatures are elevated by ∼300 K and that the thermal anomaly is broad (>500 km wide) and extends to depths ≥660 km. The dimensions of the thermal anomaly are not consistent with a starting thermal plume but are consistent with a flux of excess heat coming from the lower mantle. Such a broad thermal upwelling could be part of the African Superplume found in the lower mantle beneath southern Africa.
Summer‐winter hemispheric asymmetry of sudden increase in ionospheric total electron content induced by solar flares: A role of O/N2 ratio
Authors: Tsugawa T. , Sadakane T. , Sato J. , Otsuka Y. , Ogawa T. , Shiokawa K. , Saito A.
Published: November 2006

Latitudinal and local time dependences of the sudden increase in total electron content (SITEC) of the ionosphere induced by solar flares were statistically studied. We analyzed 91 SITEC events associated with solar flares larger than M5 X‐ray class from January 2000 to May 2005. Global total electron content (TEC) data from the Scripps Orbit and Permanent Array Center (SOPAC) GPS networks and X‐ray flux data obtained by the Geosynchronous Operational Environmental Satellites (GOES) were used in this study. The global TEC maps revealed that the SITEC value basically depends on the cosine of solar zenith angle (SZA). However, we found that there were significant residuals δ from the linear fitting to the SZA for almost all the flare events. The value of δ is statistically larger in the winter hemisphere than in the summer hemisphere. The latitudinal difference of δ is ∼0.5 TECU between 50°N and 50°S in the solstice. On the other hand, there was not a clear statistical difference in δ between the morning and evening sectors. The similar summer‐winter hemispheric asymmetry was also seen in the daytime distribution of the F region O/N2 density ratio in the MSISE‐90 model. This result indicates that the SITEC phenomena induced by solar flares depend not only on the SZA but also on the O/N2 density ratio. The daytime F region electron density and the background TEC is well known to be determined basically by the O/N2 ratio. It is reasonable that the O/N2 ratio affects the sudden increase in TEC in the same sense as it determines the background TEC.
Interaction of micropipes with foreign polytype inclusions in SiC
Authors: Gutkin M. Yu. , Sheinerman A. G. , Argunova T. S. , Yi J. M. , Kim M. U. , Je J. H. , Nagalyuk S. S. , Mokhov E. N. , Margaritondo G. , Hwu Y.
Published: November 2006

Synchrotron phase sensitive radiography, optical and scanning electron microscopies, and color photoluminescence have been used to study the interaction of micropipes with foreign polytype inclusions in 4H-SiC bulk crystals grown on 6H-SiC substrates. This combination of techniques confirms that micropipes agglomerate at the polytype inclusions and merge into pores. A mechanism for this phenomenon is suggested based on a three-dimensional theoretical model; the inclusion boundaries elastically interact with micropipes, causing them to migrate from the bulk to their equilibrium positions at the polytype boundaries. The turning of micropipes towards the inclusions is experimentally demonstrated, and the reduction of their density in nearby regions is revealed. Supported by experimental observations, our model helps to understand the pore formation and expansion in SiC bulk crystals.
The oxidized soot surface: Theoretical study of desorption mechanisms involving oxygenated functionalities and comparison with temperature programed desorption experiments
Authors: Barco Gianluca , Maranzana Andrea , Ghigo Giovanni , Causà Mauro , Tonachini Glauco
Published: November 2006

The desorption mechanism for oxygenated functionalities on soot is investigated by quantum mechanical calculations on functionalized polycyclic aromatic hydrocarbon (PAH) models and compared with recently published temperature programed desorption-mass spectrometry results. Substituents on PAHs of increasing size (up to 46 carbon atoms in the parent PAH) are chosen to reproduce the local features of an oxidized graphenic soot platelet. Initially, the study is carried out on unimolecular fragmentation (extrusion, in some cases) processes producing HO, CO, or CO2, in model ketones, carboxylic acids, lactones, anhydrides, in one aldehyde, one peroxyacid, one hydroperoxide, one secondary alcohol, and one phenol. Then, a bimolecular process is considered for one of the carboxylic acids. Furthermore, some cooperative effect which can take place by involving two vicinal carboxylic groups (derived from anhydride hydrolysis) is investigated for other four bifunctionalized models. The comparison between the computed fragmentation (desorption) barriers for the assessed mechanisms and the temperature at which maxima occur in TPD spectra (for HO, CO, or CO2 desorption) offers a suggestion for the assignment of these maxima to specific functional groups, i.e., a key to the description of the oxidized surface. Notably, the computations suggest that (1) the desorption mode from a portion of a graphenic platelet functionalized by a carboxylic or lactone groups is significantly dependent from the chemical and geometric local environment. Consequently, we propose that (2) not all carboxylic groups go lost at the relatively low temperatures generally stated, and (3) lactone groups can be identified as producing not only CO2 but also CO.
Low-temperature properties of the XY spin chain with an impurity fragment
Authors: Ezerskaya E. V. , Chovpan A. A.
Published: November 2006

The exact energy spectrum in a longitudinal magnetic field is found for an infinite XY chain (s=1∕2) with an impurity fragment. It is shown that, in addition to a continuum band and a discrete set of levels, the existence of from one to four bound states, localized at the boundaries of the impurity fragment with the main chain, is possible. The critical behavior of the local static thermodynamic characteristics and time dependence of the longitudinal dynamic correlation functions for different temperatures are studied. It is shown that local thermodynamic characteristics of the model can be influenced significantly by both the discrete levels and the bound states.
Doping and hydrogen passivation of boron in silicon nanowires synthesized by laser ablation
Authors: Fukata N. , Chen J. , Sekiguchi T. , Okada N. , Murakami K. , Tsurui T. , Ito S.
Published: November 2006

Local vibrational modes of boron (B) in silicon nanowires (SiNWs) synthesized by laser ablation were observed at about 618 and 640cm−1 by Raman scattering measurements. Boron doping was performed during the growth of SiNWs. Fano [Phys. Rev. 124, 1866 (1961)] broadening was also observed in the Si optical phonon peak. These results prove that B atoms were doped in the SiNWs. Hydrogen (H) passivation of B acceptors in the SiNWs was also investigated. A broad peak was observed at around 650–680cm−1 after hydrogenation, demonstrating that B dopants were passivated by the formation of the well-known H–B passivation centers.
Surface displacement measured by beam distortion detection technique: Application to picosecond ultrasonics
Authors: Chigarev N. , Rossignol C. , Audoin B.
Published: November 2006

A sensitive technique of surface displacement measurement without interferometry is proposed for the goals of picosecond ultrasonics. Simple description of detection mechanism is provided on the basis of paraxial approximation of light diffraction. Test experiments with gold and tungsten layers have been performed and analyzed. The efficiency of the technique is compared with interferometry and reflectometry methods.
Enhanced flux pinning properties of YBa2Cu3Oy by dilute impurity doping for CuO chain
Authors: Ishii Yui , Shimoyama Jun-ichi , Tazaki Yoshiaki , Nakashima Takayoshi , Horii Shigeru , Kishio Kohji
Published: November 2006

Effects of dilute impurity doping to the CuO chain of Y123 on the flux pinning properties were studied using single crystals and melt-solidified bulks. Cobalt-doped Y123 single crystals and iron-, cobalt- or gallium-doped Y123 melt-solidified bulks exhibited dramatically improved Jc-H characteristics accompanying huge secondary peaks in Jc-H curves. In field Jc of these samples are apparently higher than that of a low level zinc-doped bulk. These results strongly suggest that introduction of local disorders in the CuO chain by dilute impurity doping is a more promising way to improve Jc of RE123 materials than impurity doping to the CuO2 plane.
Visible band-gap ZnCdO heterostructures grown by molecular beam epitaxy
Authors: Sadofev S. , Blumstengel S. , Cui J. , Puls J. , Rogaschewski S. , Schäfer P. , Henneberger F.
Published: November 2006

Single-phase ZnCdO alloys with a band gap extending from the violet to yellow spectral range are fabricated by molecular beam epitaxy using extremely low growth temperatures in conjunction with O-rich growth conditions. The Cd concentration can be systematically adjusted via the Cd∕Zn beam pressure ratio. Despite growth temperatures as low as 150°C, layer-by-layer growth is accomplished allowing for the preparation of ZnCdO∕ZnO quantum well structures. Both epilayers and quantum wells exhibit strong band-gap-related emission at room temperature in the whole composition range.
Degradation-free interfaces in MgB2/insulator/Pb Josephson tunnel junctions
Authors: Cui Y. , Chen Ke , Li Qi , Xi X. X. , Rowell J. M.
Published: November 2006

High quality superconductor-barrier interfaces are critical for Josephson tunnel junctions. The authors show that such interfaces can be achieved in MgB2/insulator/Pb trilayer junctions using MgB2 films grown by hybrid physical-chemical vapor deposition and with barriers formed at elevated temperatures. The junctions show clear Josephson tunneling characteristics with high Jc (∼3kA∕cm2), high IcRN products (∼1.9meV), and the expected Ic(B) pattern. The observed π gap is small (2.0meV) and the σ gap is large (7.4meV), in agreement with theoretical predictions and indicating that the superconducting property of MgB2 is not degraded at the MgB2-insulator interface.
Polarization-independent liquid crystal grating on azo-dye film fabricated through intensity holography
Authors: Lu Xuemin , Lu Qinghua , Lee Fuk Kay , Tsui Ophelia K. C.
Published: November 2006

Diffraction phase gratings have found applications in many fields. In this letter the authors described how intensity holography was used to fabricate liquid crystal diffraction phase gratings on azo-dye films. The diffraction efficiency of this liquid crystal phase grating was determined to be independent of the polarization direction of incident light.
Contact network epidemiology: Bond percolation applied to infectious disease prediction and control
Authors: Meyers Lauren
Published: November 2006

Mathematics has long been an important tool in infectious disease epidemiology. I will provide a brief overview of compartmental models, the dominant framework for modeling disease transmission, and then contact network epidemiology, a more powerful approach that applies bond percolation on random graphs to model the spread of infectious disease through heterogeneous populations. I will derive important epidemiological quantities using this approach and provide examples of its application to issues of public health.
NuMA Influences Higher Order Chromatin Organization in Human Mammary Epithelium
Authors: Abad Patricia C. , Lewis Jason , Mian I. Saira , Knowles David W. , Sturgis Jennifer , Badve Sunil , Xie Jun , Lelièvre Sophie A.
Published: November 2006

The coiled-coil protein NuMA is an important contributor to mitotic spindle formation and stabilization. A potential role for NuMA in nuclear organization or gene regulation is suggested by the observations that its pattern of nuclear distribution depends upon cell phenotype and that it interacts and/or colocalizes with transcription factors. To date, the precise contribution of NuMA to nuclear function remains unclear. Previously, we observed that antibody-induced alteration of NuMA distribution in growth-arrested and differentiated mammary epithelial structures (acini) in three-dimensional culture triggers the loss of acinar differentiation. Here, we show that in mammary epithelial cells, NuMA is present in both the nuclear matrix and chromatin compartments. Expression of a portion of the C terminus of NuMA that shares sequence similarity with the chromatin regulator HPC2 is sufficient to inhibit acinar differentiation and results in the redistribution of NuMA, chromatin markers acetyl-H4 and H4K20m, and regions of deoxyribonuclease I-sensitive chromatin compared with control cells. Short-term alteration of NuMA distribution with anti-NuMA C-terminus antibodies in live acinar cells indicates that changes in NuMA and chromatin organization precede loss of acinar differentiation. These findings suggest that NuMA has a role in mammary epithelial differentiation by influencing the organization of chromatin.
Protein encoded by HSV‐1 stimulation‐related gene 1 (HSRG1) interacts with and inhibits SV40 large T antigen
Authors: Guo H. X. , Cun W. , Liu L. D. , Dong S. Z. , Wang L. C. , Dong C. H. , Li Q. H.
Published: November 2006

Abstract.  Herpes simplex virus (HSV)‐1 stimulation‐related gene 1 (HSRG1) protein expression is induced in HSV‐1 infected cells. We found that HSRG1 interacts with SV40 large T antigen (LT) in yeast two‐hybrid assay and bimolecular fluorescence complementation (BiFC) assay. This interaction alters LT's regulation of the SV40 promoter and its ability to influence the cell cycle. Choramphenicol acetyl‐transferase (CAT) assays revealed that initiation of gene transcription by LT is changed by HSRG1 expression. HSRG1 inhibits the ability of LT to activate SV40 late gene transcription. Further data indicate that the ability of LT protein to stimulate S‐phase entry is also inhibited by the expression of HSRG1. The results of a colony‐forming assay suggested that expression of HSRG1 in cells transfected by LT gene decreased the rate of colony formation. Yeast two‐hybrid β‐galactosidase assay revealed that amino acid residues 132–450 in LT bind HSRG1.
Classification of protein content and technological properties of eighteen wheat varieties grown in Iran
Authors: Sahari Mohammad Ali , Gavlighi Hassan Ahmadi , Tabrizzad Mohammad Hossein Azizi
Published: November 2006

The best method for wheat planning and its food industrial usage is evaluation of its technological properties. Classification of protein content and some technological properties of eighteen important Iranian wheat cultivars were investigated. Statistical analysis revealed, highest protein content (11%), protein quality (SDS = 35.6 mL), hardness degree (63%), in Rooshan of Karaj (I), Zagroos of Ahvaz (K) and Marvdasht of Karaj (O) varieties, respectively. On the basis of the quality, the Zagross of Ahvaz (K), Zarrine of Aurumieh (L), Rooshan of Karaj (I), and Chamran of Ahvaz (D) varieties were recognized for their farinograph and extensograph characteristics (water absorption = 61–65%, dough development time = 2.3–5.3 min, dough stability to break down = 15–19.3 min, mixing tolerance index = 22.3–32.3 BU, valorimetry index = 55–64.3 Unit, maximum resistance to extension = 134–450 BU, dough energy = 11.3–100.3 cm2 and extensibility = 156–179 mm). The dendrogram was classified into four groups and in general, the wheat cultivar K was the most separated from the other cultivars, followed by L and I.
Effect of extrusion parameters on flavour retention, functional and physical properties of mixtures of starch and d‐limonene encapsulated in milk protein
Authors: Yuliani Sri , Torley Peter J. , D'Arcy Bruce , Nicholson Timothy , Bhandari Bhesh
Published: November 2006

The purpose of this research was to investigate the retention of flavour volatiles encapsulated in water‐insoluble systems during high temperature–short time extrusion process. A protein precipitation method was used to produce water‐insoluble capsules encapsulating limonene, and the capsules were added to the extruder feed material (cornstarch). A twin‐screw extruder was used to evaluate the effect of capsule level of addition (0–5%), barrel temperature (125–145 °C) and screw speed (145–175 r.p.m.) on extruder parameters (torque, die pressure, specific mechanical energy, residence time distribution) and extrudate properties [flavour retention, texture, colour, density, expansion, water absorption index, water solubility index (WSI)]. Capsule level had a significant effect on extrusion conditions, flavour retention and extrudate physical properties. Flavour retention increased with the increase in capsule level from 0% to 2.5%, reached a maximum value at capsule level of 2.5% and decreased when the capsule level increased from 2.5% to 5%. The die pressure, torque, expansion ratio, hardness and WSI exhibited the opposite effect with the presence of capsules.
Effect of partial baking, storage and rebaking process on the quality of white pan bread
Authors: Murat Karaoğlu Mehmet , Gürbüz Kotancilar Halis
Published: November 2006

The effect of par‐baking, antimicrobial additive (calcium‐propionate) and refrigerator storage on the aging behaviour and quality of white pan bread was evaluated. Breads were par‐baked for 10, 15, 20 min at 230°C, with and without Ca‐propionate (0.2%), and were stored at refrigerator temperature (4°C) for 7, 14, 21 days, wrapped with two polyethylene bags. After storage, rebaked breads were subject to moisture, baking loss, volume, hydration capacity, softness, total titratable acidity (TTA) and colour analysis. Addition of Ca‐propionate significantly decreased crust moisture content, baking loss, specific volume, hydration capacity and softness values of white pan bread, while crumb moisture content, acidity and a colour value significantly increased. Initial baking time of rebaked white pan bread had a significant effect on moisture, specific volume, hydration capacity, softness, TTA and colour of bread. Regarding the crumb softness, 10 min of initial baking time gave the softest white pan bread crumb. The increase in the time of intermediate storage of the par‐baked bread leads to a decrease in the quality of the resulting full baked bread, namely a loss in the moisture content, softness and an increase of the baking loss, specific volume. The rebaked white pan bread, which was par‐baked for 10 min and stored for 7 and 14 days at refrigerator temperature, gave softer crumb than the control group.
Rheological behaviour of biscuit dough in relation to water mobility
Authors: Assifaoui Ali , Champion Dominique , Chiotelli Eleni , Verel Aliette
Published: November 2006

In this article, we were interested in the study of biscuit dough after kneading. Previous studies have shown that the dynamic properties of water and its distribution within dough influence the rheological behaviour and the machinability of dough. The viscoelastic characteristics of dough were determined with dynamic mechanical thermal analysis, whereas the water mobility in the dough was studied using low‐field nuclear magnetic resonance of the proton (1H‐NMR). The influence of water content and temperature on both elastic component and proton spin–spin relaxation time was studied. We showed that the evolution of proton relaxation time measurements T2 at a molecular scale can be correlated to the rheological behaviour of dough at a mesoscopic level.
Circulating intestinal fibroblast growth factor 19 has a pronounced diurnal variation and modulates hepatic bile acid synthesis in man
Authors: LUNDÅSEN T. , GÄLMAN C. , ANGELIN B , RUDLING M.
Published: November 2006

Bile acids (BAs) traversing the enterohepatic circulation exert several important metabolic effects. Their hepatic synthesis, controlled by the enzyme cholesterol 7α‐hydroxylase (CYP7A1), has a unique diurnal variation in man. Here we provide evidence that the transintestinal flux of BAs regulates serum levels of intestinal fibroblast growth factor 19 (FGF19) that in turn modulate BA production in human liver. Basal FGF19 levels varied by 10‐fold in normal subjects, and were reduced following treatment with a BA‐binding resin and increased upon feeding the BA chenodeoxycholic acid. Serum FGF19 levels exhibited a pronounced diurnal rhythm with peaks occurring 90–120 min after the postprandial rise in serum BAs. The FGF19 peaks in turn preceded the declining phase of BA synthesis. The diurnal rhythm of serum FGF19 was abolished upon fasting. We conclude that, in humans, circulating FGF19 has a diurnal rhythm controlled by the transintestinal BA flux, and that FGF19 modulates hepatic BA synthesis. Through its systemic effects, circulating FGF19 may also mediate other known BA‐dependent effects on lipid and carbohydrate metabolism.
Reproductive strategy, clonal structure and genetic diversity in populations of the aquatic macrophyte Sparganium emersum in river systems
Authors: POLLUX B. J. A. , JONG M. D. E. , STEEGH A. , VERBRUGGEN E. , VAN GROENENDAEL J. M. , OUBORG N. J.
Published: November 2006

Many aquatic and riparian plant species are characterized by the ability to reproduce both sexually and asexually. Yet, little is known about how spatial variation in sexual and asexual reproduction affects the genotypic diversity within populations of aquatic and riparian plants. We used six polymorphic microsatellites to examine the genetic diversity within and differentiation among 17 populations (606 individuals) of Sparganium emersum, in two Dutch‐German rivers. Our study revealed a striking difference between rivers in the mode of reproduction (sexual vs. asexual) within S. emersum populations. The mode of reproduction was strongly related to locally reigning hydrodynamic conditions. Sexually reproducing populations exhibited a greater number of multilocus genotypes compared to asexual populations. The regional population structure suggested higher levels of gene flow among sexually reproducing populations compared to clonal populations. Gene flow was mainly mediated via hydrochoric dispersal of generative propagules (seeds), impeding genetic differentiation among populations even over river distances up to 50 km. Although evidence for hydrochoric dispersal of vegetative propagules (clonal plant fragments) was found, this mechanism appeared to be relatively less important. Bayesian‐based assignment procedures revealed a number of immigrants, originating from outside our study area, suggesting intercatchment plant dispersal, possibly the result of waterfowl‐mediated seed dispersal. This study demonstrates how variation in local environmental conditions in river systems, resulting in shifting balances of sexual vs. asexual reproduction within populations, will affect the genotypic diversity within populations. This study furthermore cautions against generalizations about dispersal of riparian plant species in river systems.
Between a rock and a hard place: evaluating the relative risks of inbreeding and outbreeding for conservation and management
Authors: EDMANDS SUZANNE
Published: November 2006

As populations become increasingly fragmented, managers are often faced with the dilemma that intentional hybridization might save a population from inbreeding depression but it might also induce outbreeding depression. While empirical evidence for inbreeding depression is vastly greater than that for outbreeding depression, the available data suggest that risks of outbreeding, particularly in the second generation, are on par with the risks of inbreeding. Predicting the relative risks in any particular situation is complicated by variation among taxa, characters being measured, level of divergence between hybridizing populations, mating history, environmental conditions and the potential for inbreeding and outbreeding effects to be occurring simultaneously. Further work on consequences of interpopulation hybridization is sorely needed with particular emphasis on the taxonomic scope, the duration of fitness problems and the joint effects of inbreeding and outbreeding. Meanwhile, managers can minimize the risks of both inbreeding and outbreeding by using intentional hybridization only for populations clearly suffering from inbreeding depression, maximizing the genetic and adaptive similarity between populations, and testing the effects of hybridization for at least two generations whenever possible.