bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Duplex steel Uranus 76N during deformation and heat treatment
Authors: Lecomte‐Beckers J. , Moureaux P. , Carton M. , Habraken A.‐M.
Published: November 2006

Duplex Uranus 76N is characterized by metallography, thermal and mechanical analysis. The investigation shows that the microstructure of such a Duplex strongly depends on the cooling conditions determining the quantity of austenite formed in the ferrite matrix. Numerical simulations of 76N behavior during the rolling process and service life require the knowledge of the recrystallization state during rolling steps at high temperature, thermal parameters such as dilatation, density, specific heat, thermal diffusivity, thermal conductivity and mechanical constitutive laws. These material parameters are determined and presented in this study. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of heavy metal oxide glasses before and after g‐irradiation
Authors: Sharma G. , Thind K. S. , Monika  , Singh H. , Manupriya  , Gerward L.
Published: November 2006

The effect of gamma irradiation has been probed by transmission measurements before and after γ‐irradiation on lead borate and bismuth borate glasses of varying composition by exposing with 60Co radioisotope of absorbed dose 2.5 kGy. The induced absorption coefficient, effect of irradiation on optical band gap, width of tail and cut off wavelength are discussed by taking into account the possible dependence of radiation hardness on composition and defects produced in a glass matrix. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrasonic properties of Cu45Zr(45–x)HfxAg10 glassy alloys
Authors: Fukuhara Mikio , Jia Fei , Zhang Wei , Inoue Akihisa
Published: November 2006

Using ultrasonics, the acoustic characteristics of Cu45Zr(45–x)Hfx Ag10 (x = 0–25) glassy alloys were examined in terms of complex elasticity. The values of bulk modulus (K), Lamè parameter (λ), Young's (E) and shear (G) moduli of Cu45Zr(45–x)Hfx Ag10 glassy alloys are found to have a unique order for metallic materials, except for polymers. The large Poisson ratio (∼0.421) and the lower G /K ratio (∼0.167) at 25 at% Hf indicate rubbery characteristics that readily undergo uniaxial volume‐preserving deformation but resist three‐dimensional nonvolume‐preserving deformation. The complex dynamic viscosity shows that visco‐elasticity of the glassy alloys is dominated by shear motion. The large peaks in K and λ, and small ones in E and G at 5 at% Hf, and one large peak in the shear attenuation coefficient at 2.5 at% Hf, may indicate atomic morphological change by electron‐transverse phonon coupling. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structure of CuFeInSe3 from X‐ray powder diffraction data
Authors: Mora Asiloé J. , Delgado Gerzon E. , Grima‐Gallardo Pedro
Published: November 2006

The crystal structure of the adamantane compound CuFeInSe3, belonging to the system (CuInSe2)1–x (FeSe)x with x = 0.5, was analyzed using X‐ray powder diffraction data. Several model structures were derived from the structure of the selenium rich phase CuInSe2.3 by permuting the cations in the available Wyckoff positions. The refinement of the best model by the Rietveld method in the tetragonal space group P$ \bar 4 $2c (Nº 112), Z = 1, with unit cell parameters a = 5.7762(2) Å, c = 11.5982(7) Å and V = 386.97(3) Å3 led to Rp = 8.0%, Rwp = 9.6%, Rexp = 6.2% and χ2 = 1.7 for 134 independent reflections. The model that best fitted the diffraction data has the following atomic distribution: Cu in Wyckoff site 2f; Fe in Wyckoff site 2d; In in Wyckoff site 2b and 1/3Cu, 1/3Fe, 1/3In in Wyckoff site 2f; Se in Wyckoff site 8n. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
XPS characterization of nitrogen‐doped carbon nanotubes
Authors: Morant C. , Andrey J. , Prieto P. , Mendiola D. , Sanz J. M. , Elizalde E.
Published: November 2006

Due to a most unfortunate mistake, Fig. 3 was wrongly printed in the original article. This Erratum is intended to present the proper Fig. 3. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
250 µm long anodic TiO2 nanotubes with hexagonal self‐ordering
Authors: Albu Sergiu P. , Ghicov Andrei , Macak Jan M. , Schmuki Patrik
Published: November 2006

In this work we show that the growth of more than 250 µm thick self‐organized TiO2 nanotube layers is possible, using an electrochemical approach in organic electrolytes. The tubes can grow as a hexagonal close packed pore array. Crucial parameters that decide on the dimensions are the fluoride ion concentration, the voltage and the anodization time. Self‐organized tube formation is restricted to a critical parameter range. Highest aspect ratio tubes can be achieved under a set of very optimized conditions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

magnified image
An improved analytical method for the determination of urea nitrogen isotopomers in biological samples utilizing continuous flow isotope ratio mass spectrometry
Authors: Marini Juan C. , Attene‐Ramos Matias Sebastian
Published: November 2006

Over the past few years numerous dual inlet isotope ratio mass spectrometry (IRMS) applications have been adapted to continuous flow systems which allow the automation of sample admission and a higher throughput. The isotopomer analysis of urea nitrogen by IRMS requires the offline conversion of urea into nitrogen gas before analysis. The oxidation of urea with LiOBr results in the monomolecular degradation of urea, which preserves the identity of the parent urea molecule, and has to be conducted under vacuum to prevent contamination with atmospheric nitrogen. We have developed an offline system of urea degradation utilizing disposable Exetainers, in which atmospheric nitrogen is displaced by helium. Recovery of urea nitrogen was linear within the range of the standards tested (0 to 420 µg nitrogen) and standard curves for 15N15N‐urea standards showed high coefficients of determination (R2 > 0.9998). A small portion of urea degrades in a non‐monomolecular fashion and has been shown to depend on the concentration of urea in the sample. Long‐term storage of prepared samples showed a decline in 15N15N enrichment, suggesting air contamination. However, samples were stable for 24 h, which allows for the analysis of large sample batches. Interest in urea metabolism, particularly in ruminant species, has increased recently due to the environmental implications of urea and nitrogen excretion by farm animals. This novel analytical method will allow for accurate measurements and the rapid throughput needed in order to support these field studies. Copyright © 2006 John Wiley & Sons, Ltd.
Feedback stabilization of bifurcations in multivariable nonlinear systems—Part II: Hopf bifurcations
Authors: Wang Yong , M. Murray Richard
Published: November 2006

In this paper we derive necessary and sufficient conditions of stabilizability for multi‐input nonlinear systems possessing a Hopf bifurcation with the critical mode being linearly uncontrollable, under the non‐degeneracy assumption that stability can be determined by the third order term in the normal form of the dynamics on the centre manifold. Stabilizability is defined as the existence of a sufficiently smooth state feedback such that the Hopf bifurcation of the closed‐loop system is supercritical, which is equivalent to local asymptotic stability of the system at the bifurcation point. We prove that under the non‐degeneracy conditions, stabilizability is equivalent to the existence of solutions to a third order algebraic inequality of the feedback gains. Explicit conditions for the existence of solutions to the algebraic inequality are derived, and the stabilizing feedback laws are constructed. Part of the sufficient conditions are equivalent to the rank conditions of an augmented matrix which is a generalization of the Popov–Belevitch–Hautus (PBH) rank test of controllability for linear time invariant (LTI) systems. We also apply our theory to feedback control of rotating stall in axial compression systems using bleed valve as actuators. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of alloying elements and etching treatment on the passivating films formed on aluminium alloys
Authors: Feliu S. , Bartolomé M. J.
Published: November 2006

This paper studies the characteristics of aluminium oxide layers present on the surface of commercial aluminium specimens after thermomechanical processing and after subsequent etching in an alkaline solution, highlighting the main differences observed. An attempt is made to establish possible relationships between alloying elements and the characteristics of these layers. Copyright © 2006 John Wiley & Sons, Ltd.
Atomic force microscopy imaging of ZnO nanodots deposited on quartz by sparking off different tip shapes
Authors: Kumpika T. , Thongsuwan W. , Singjai P.
Published: November 2006

We have demonstrated a simple method for depositing ZnO nanodots on quartz substrates by sparking off different tip shapes at voltages of 2, 4 and 6 kV in air at atmospheric pressure. A comparison was made among the three tip shapes: the sharp tip, the conical tip and the dull tip. The surface morphology was then observed by atomic force microscopy. The mean height of the randomly distributed dots of approximately 8 nm was successfully deposited from the sharp tip at 6 kV. Characterizations by UV–vis spectroscopy and Raman spectroscopy have confirmed the presence of ZnO and the quality improvement by annealing treatments. Moreover, a nucleation mechanism of the nanodot formation is discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Study of the first nucleation steps of thin films by XPS inelastic peak shape analysis
Authors: Mansilla C. , Gracia F. , Martin‐Concepción A. I. , Espinós J. P. , Holgado J. P. , Yubero F. , González‐Elipe A. R.
Published: November 2006

The initial steps in the formation of thin films have been investigated by analysis of the peak shape (both inelastic background and elastic contributions) of X‐ray photoelectron spectra. Surface coverage and averaged height of the deposited particles have been estimated for several overlayers (nanometre range) after successive deposition cycles. This study has permitted the assessment of the type of nucleation and growth mechanisms of the films. The experiments have been carried out in situ in the preparation chamber of an XPS spectrometer. To check the performance of the method, several materials (i.e. cerium oxide, vanadium oxide and cadmium sulfide) have been deposited on different substrates using a variety of preparation procedures (i.e. thermal evaporation, ion beam assisted deposition and plasma enhanced chemical vapour deposition). It is shown that the first deposited nuclei of the films are usually formed by three‐dimensional particles whose heights and degree of surface coverage depend on the chemical characteristics of the growing thin film and substrate materials, as well as the deposition procedure. It is concluded that XPS peak shape analysis can be satisfactorily used as a general method to characterize morphologically the first nanometric moieties that nucleate a thin film. Copyright © 2006 John Wiley & Sons, Ltd.
Aerosol damage to a microchannel plate analysed by X‐ray photoelectron spectromicroscopy
Authors: Walton John
Published: November 2006

Localised corrosion on a microchannel plate has been studied using X‐ray photoelectron spectromicroscopy. Curve fitting to the spectra at each pixel in the image data set reveals the presence of sodium and carbonate species at the corrosion sites, which optical microscopy suggests originated as droplets. It is proposed that aerosol contamination of the alkali enriched microchannel plate during removal of particulate material using a stream of compressed gas was responsible for the initiation of corrosion. Copyright © 2006 John Wiley & Sons, Ltd.
Accurate measurement of sputtered depth for ion sputtering rates and yields: the mesh replica method
Authors: Seah M. P. , Geller J. , Suzuki M.
Published: November 2006

For the accurate measurements of crater depths, ion sputtering rates and ion sputtering yields in studies of sputter‐depth profiling using Auger electron spectroscopy (AES) or X‐ray photoelectron spectroscopy (XPS), a proposed mesh replica method has been evaluated. In this method, during ion sputtering, grids of between 50 and 400 mesh (per inch) are placed on the sample to retain unsputtered regions of the original surface to be used as reference. This enables a more accurate measurement of the depth to be made using a stylus profilometer close to the analytical region. The closer‐pitch meshes were thought to offer the prospect of measurements of higher accuracy. Calculations show that sputter deposits from the mesh sides may limit the mesh numbers used to 100 or those of a wider pitch for both stationary and rotated samples. A correlation with published data for stationary samples and new data for rotated samples confirms the calculations. In practice, it is difficult, without a special holder, to have intimate contact between the grid and sample. Such a holder is described. Further calculations concerning the shadowed profiles at the grid bar regions show that the grids may lift off the sample surface by 4–16 µm. This leads to non‐vertical crater walls in each mesh aperture. This effect, however, does not change the above conclusion on the mesh sizes to be used. In this range, the spurious appearance of Auger electrons emitted from the grid material is calculated to be less than 1%. This conclusion applies to the meshes evaluated here, which range in thickness from 13 to 29 µm. Thinner meshes may lead to the applicability of proportionately closer meshed grids in sputter‐profiling applications. Copyright © 2006 John Wiley & Sons, Ltd. The contribution of Martin P. Seah of the National Physical Laboratory is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.
Nanoscience of single polymer chains revealed by nanofishing
Authors: Nakajima Ken , Nishi Toshio
Published: November 2006

The invention of atomic force microscopy (AFM) enabled us to study the statistical properties of single polymer chains by a method called “nanofishing,” which stretches a single polymer chain adsorbed on a substrate with its one end by picking it at the other end. A force‐extension curve obtained for a single polystyrene chain in a Θ solvent (cyclohexane) shows good agreement with a worm‐like chain model and, therefore, gives microscopic information about entropic elasticity. Furthermore, the nanofishing technique can be used for dynamic viscoelastic measurement of single polymer chains. An AFM cantilever is mechanically oscillated at its resonant frequency during the stretching process. This technique enables the estimation of quantitative and simultaneous elongation‐dependent changes of stiffness and viscosity of a single chain with the use of a phenomenological model. In this study, the effect of solvent on viscosity in low extension regions reveals that the viscosity is attributed to monomer‐solvent friction. Thus, static and dynamic nanofishing techniques are shown to give powerful experimental proofs for several basic questions in polymer physics. The techniques are expected to reveal hidden properties of polymer chains or polymer solutions by any types of macroscopic measurements in the future. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 249–258; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20092
The lipid components of white potato tubers (Solanum tuberosum)
Authors: Lepage Marius
Published: November 2006

Four Canadian varieties of potatoes were examined for their lipid composition. Lipids, extracted with chloroformmethanol, were shown by TLC and column chromatography to consist of 16.5% neutral lipids, 45.5% phospholipids and 38.1% glycolipids. Among the phospholipids and glycolipids, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, the galactolipids and the sterol glucosides were the major lipids. The predominant fatty acids were palmitic (19.5%), linoleic (44.8%) and linolenic (30.4%, in Kennebec). Analyses of the fatty acids of stored potatoes showed a marked decrease in linoleic acid and an increase in linolenic acid, in the Irish Cobbler and Sebago potatoes. β‐sitosterol comprised 85.0% of total sterols. Nearly half of the carotenoids was lutein (xanthophyll), the others being α‐carotene, β‐carotene, an unidentified pigment and lutein epoxide.
Bacterial hydrocarbons: Occurrence, structure and metabolism
Authors: Albro Phillip W. , Dittmer John C.
Published: November 2006

The chemical structures, general pathways of catabolism and the biosynthesis of bacterial, nonisoprenoid hydrocarbons are reviewed with emphasis on recent work on the chemistry and biosynthesis of the hydrocarbons ofSarcina lutea.
Effects of hydrogen peroxide on lipoproteins and associated lipids
Authors: Clark Dale A. , Foulds Emmett L. , Wilson Fredrick H.
Published: November 2006

Lipoproteins isolated from human or chimpanzee serum were treated with H2O2 and allowed to stand varying lengths of time before quantitative analysis in the ultracentrifuge. Marked instability of ultracentrifugal boundaries (convection) occurred during the first 24 hr, but diminished thereafter. Simultaneously, the quantity of lipoprotein decreased. The instability of boundaries in H2O2‐treated samples was presumed to reflect loss of lipid‐protein affinity and breakdown of lipoproteins under the force of ultracentrifugation. Analysis of extracted lipids showed that H2O2 caused little loss of phospholipid, significant loss of triglyceride, and apparent loss of cholesteryl ester. The latter loss, however, was accompanied by appearance of esterified cholesterol in the free cholesterol eluent. Apparently H2O2 converted some cholesteryl esters to a more polar form which was eluted later from the column, with the free cholesterol fraction. Gas chromatographic analysis of the fractions eluted from the column showed that selective degradation of polyunsaturated fatty acids was most marked with cholesteryl esters, somewhat less with triglycerides, and negligible with phospholipids. It was postulated that the loss of lipid‐protein affinity caused by H2O2 in vitro may reflect a similar process in vivo, i.e., that one process contributing to development of atherosclerosis can be oxidation of lipoprotein, with loss of lipid‐protein affinity and accumulation of lipid products in (or on) cells of the vascular system.
Variation with chain length in acute toxicity of alkylhydroxamic acids to salmon (Salmo salar) fry
Authors: Addison R. F. , Côté R. P.
Published: November 2006

The acute toxicity of saturatedn‐alkylhydroxamic acids to salmon (Salmo salar) fry was determined. Within the seriesn‐C6H13CONHOH ton‐C10H21CONHOH, acute toxicity (indicated by death) increased with chain length. Shorter and longer chain compounds were not toxic under similar conditions. Factors governing the variation in toxicity with chain length and possible mechanisms of action are discussed.
Influence of medium‐chain triglycerides on lipid metabolism in the rat
Authors: Leveille Gilbert A. , Pardini Ronald S. , Tillotson Jerry Ann
Published: November 2006

Lipid metabolism was studied in rats fed diets containing corn oil, coconut oil, or medium‐chain triglyceride (MCT), a glyceride mixture containing fatty acids of 8 and 10 carbons in length. The ingestion of MCT‐supplemented, cholesterolfree diets depressed plasma and liver total lipids and cholesterol as compared with corn oil‐supplemented diets. In rats fed cholesterol‐containing diets, plasma cholesterol levels were not influenced by dietary MCT, but liver cholesterol levels were significantly lower than in animals fed corn oil. In vitro cholesterol synthesis from acetate‐1‐14C was lower in liver slices of rats that consumed MCT than in similar preparations from corn oil‐fed rats. Studies of fatty acid carboxyl labeling from acetate‐1‐14C and the conversion of palmitate‐1‐14C to C18 acids by liver slices showed that chain‐lengthening activity is greater in the liver tissue of rats fed MCT than in the liver of animals fed corn oil. The hepatic fatty acid desaturation mechanisms, evaluated by measuring the conversion of stearate‐2‐14C to oleate, was also enhanced by feeding MCT.

Adipose tissue of rats fed MCT converts acetate‐1‐14C to fatty acids at a much faster rate than does tissue from animals fed corn oil. Evidence is presented to show that the enhanced incorporation of acetate into fatty acids by the adipose tissue of rats fed MCT represents de novo synthesis of fatty acids and not chain‐lengthening activity. Data are also presented on the fatty acid composition of plasma, liver, and adipose tissue lipids of rats fed the different fats under study.
Fatty acid distribution in lipids and32P incorporation into phospholipids during early amphibian development
Authors: Barassi C. A. , Bazan N. G.
Published: November 2006

Several aspects of lipid composition and32P incorporation were studied during early embryogenesis of the toad,Bufo arenarum, Hensel. The surveyed stages ranged from unfertilized oocyte to neural tube formation. The fatty acid distribution in polar and neutral lipids, as well as in acetone eluate from Unisil columns was similar in unfertilized oocyte and late blastula stage. There was no significant effect of cell cleavage on the fatty acid composition of these lipid fractions. Neutral lipids represent ca. 67% of the total lipids. The main components of the phospholipids were phosphatides of choline and ethanolamine. The total lipid and phospholipid content does not change through the studied stage of neurula. However a large increment in the phospholipid's specific radioactivity occurs when32P is injected along with the hormone to induce ovulation. It is suggested that this may reflect changes in turnover rates rather than net biosynthesis. Since a large amount of cell membranes is being formed during the early development and because the level of phospholipids remains constant, an explanation is offered regarding membranogenesis. Active phospholipid biosynthesis may take place during oogenesis. These lipids may be stored in the yolk platelet, and fertilization may regulate the functioning of a transport mechanism to corresponding membrane sites. The increased incorporation of32P may reflect changes in the activity of new membranes.
Effect of double bond position in octadecenoates upon hydrolysis by pancreatic lipase
Authors: Heimermann Wayne H. , Holman Ralph T. , Gordon Dennis T. , Kowalyshyn Doris E. , Jensen Robert G.
Published: November 2006

Fifteen triacylglycerols containing 12∶0, 14∶0, 16∶0, 18∶2 and one positional isomer ofcis‐18∶1 were hydrolyzed by pancreatic lipase (EC 3.1.1.3, glycerol ester hydrolase). The fatty acids in the products of lipolysis were identified and measured by gas liquid chromatography. The substrates containing the Δ2 through Δ7 isomers of 18∶1 were resistant to pancreatic lipolysis. These isomers accumulated in the di‐ and residual triacylglycerols and were diminished in the free fatty acids. The discrimination was greates against the Δ5 isomer.
Skin surface lipids of the dog
Authors: Sharaf David M. , Clark Stanley J. , Downing Donald T.
Published: November 2006

The skin surface lipid of the dog has been reported to contain a high proportion of diol diesters having a lower mobility on thin layer chromatography than diesters from other species in spite of containing similar fatty acid and diol components. In the present study, dog skin surface lipid was separated by preparative thin layer chromatography into sterol esters (42%), wax diesters (32%), free sterols (9%), polar lipids (7%), and unidentified components (10%). The diesters contained 1,2‐diols, each esterified with one long chain fatty acid and one isovaleric acid moiety. The diols were principally branched chain C21 and C22 compounds while the long chain fatty acids esterified with them were mainly C20 and C21 branched compounds. The fatty acids from the sterol esters were mostly saturated, branched chain C19 to C23, together with 7% of straight chain monoenoic acids, principally C21 and C22. There were only trace amounts of free sterols other than cholesterol, while the esterified sterols contained 96% cholesterol and 4% lathosterol.
Specific distribution of fatty acids in the triglycerides of rainbow trout adipose tissue. Influence of temperature
Authors: Leger C. , Bergot P. , Luquet P. , Flanzy J. , Meurot J.
Published: November 2006

In the trout, the unsaturated fatty acids are preferentially located in the β‐position and the saturated fatty acids in the α‐position of triglycerides. This fatty acid distribution is retained even with diets containing lard. The fish are, therefore, able to modify completely the fatty acid distribution of dietary triglycerides. There is no retention of the β‐monoglyceride structure during the biosynthetic processes. However, the modification of the dietary fatty acid distribution by the trout seems to be more difficult at 18 C than at 10C.
15,18,21,24‐triacontatetraenoic and 15,18,21,24,27‐triacontapentaenoic acids: New C30 fatty acids from the marine spongeCliona celata
Authors: Litchfield Carter , Tyszkiewicz John , Marcantonio Eugene E. , Note Gregory
Published: November 2006

The marine sponseCliona celata contains 3.5% 30∶4ω6 and 7.0% 30∶5w3 in its total fatty acids. These C30 polyunsaturated structures are unknown in other living organisms. Both acids occur mainly as phosphatidylserine esters.
Variations in the molecular species of lung phosphatidylglycerol
Authors: Okano Goroh , Akino Toyoaki
Published: November 2006

Approximately 20% of the phosphatidylglycerol of the lung tissue of several animals was found to have both fatty acids saturated. Pulmonary washings from the lung of the rabbit and guinea pig had more saturated phosphatidylglycerol than the washed lung tissue. Lung‐saturated phosphatidylglycerol was relatively low in the perinatal period, a time during which saturated phosphatidylcholine accumulated predominantly. This suggests that the metabolism of the saturated species of lung phosphatidylcholine and phosphatidylglycerol, which are considered to be the major pulmonary surfactants, may not be regulated in the same manner, at least in the perinatal lung.
The importance of the steric configuration of lysophosphatidylcholine in the lymphatic transport of fat
Authors: O'doherty P. J. A.
Published: November 2006

The importance of the steric configuration of lysophosphatidylcholine in the lymphatic transport of fat was investigated in bile fistula rats. It was found that the feeding of 1‐palmitoyl‐sn‐glycero‐3‐phosphocholine increased the lymphatic output of phosphatidyl choline and triacylglycerol, while the feeding of 3‐palmitoyl‐sn‐glycero‐1‐phosphocholine had no effect. In intestinal microsomes of the bile fistula rats, it was found that the lysophosphatidylcholine acyltransferase was stereospecific in acylating the 1‐acyl‐sn‐glycero‐3‐phosphocholine enantiomer. The significance of these findings is briefly discussed.
A method for the quantitative estimation of cholesterol α‐oxide in eggs
Authors: Tsai L. S. , Ijichi K. , Hudson C. A. , Meehan J. J.
Published: November 2006

A method for the quantitation of cholesterol α‐oxide in egg and egg products is described. Total lipids extracted from dry egg samples were fractionated on a silicic acid column to concentrate cholesterol oxides which were then quantitatively determined by gas liquid chromatography (GLC). Those samples which showed cholesterol oxides by GLC were further analyzed by high pressure liquid chromatography (HPLC) for the ratio of cholesterol α‐oxide and cholesterol β‐oxide. Cholesterol α‐oxide content was calculated from the combined results of GLC and HPLC.
Characterization of triterpene alcohols of seed oils from some species of theaceae, phytolaccaceae and sapotaceae
Authors: Itoh Toshihiro , Uetsuki Toshimitsu , Tamura Toshitake , Matsumoto Taro
Published: November 2006

Triterpene alcohol constituents of the unsaponifiable lipids separated from tea seed oil fromThea sinensis L. (Theaceae), camellia seed oil fromCamellia japonica L. (Theaceae), pokeweed seed oil fromPhytolacca americana L. (Phytolaccaceae) and shea butter from the seed kernels ofButyrospermum parkii (Sapotaceae) were studied. Among a number of triterpene alcohols present in these oils, 19 components were identified as cycloartenol, 24‐methylenecycloartanol, parkeol, 24‐methylene‐24‐dihydroparkeol, lanosterol, euphol, butyrospermol, tirucallol, tirucalla‐7,24‐dienol, dammaradienol, 24‐methylenedammarenol, α‐amyrin, β‐amyrin, lupeol, germanicol, taraxasterol, ψ‐taraxasterol, taraxerol and myricadiol. Tirucalla‐7,24‐dienol and butyrospermol are the predominant components of the 2 Theaceae and pokeweed seed oils. Shea butter, on the other hand, contains α‐amyrin followed by butyrospermol and lupeol as the major triterpene constituents.
The Di‐ and triesters of the lipids of steer and human meibomian glands
Authors: Nicolaides N. , Santos Evelyn C.
Published: November 2006

Three groups of diesters have been isolated and identified in the lipids of steer meibomian glands. The first group, designated as α Type I, with the abbreviated formula FA‐αOHFA‐FA1c, consisted of α‐hydroxy fatty acids esterified to fatty acids and fatty alcohols in the approximate molar ratio 1∶1∶1. The second group, designated as ω Type I‐St, with the abbreviated formula FA‐ωOHF A‐St, consisted of ω‐hydroxy fatty acids esterified to fatty acids and sterols in the approximate molar ratio 1∶1∶1. The third group, designated as α,ω Type II, with the abbreviated formula FA‐α,ωdiol‐FA, consisted of α,ω‐diols esterified to 2 moles of fatty acids. The sum of the different diesters comprised about 9% of total steer meibomian lipids.

Capillary GLC of the fatty acids of αType I diesters showed the fatty acids to be a family with a two‐cluster profile, one at C12 to C20 and the other at C21 to C31, with anteiso chains predominating. Fatty acids from ωType I‐St and α,ωType II diesters gave mainly a one‐cluster profile in the short long chain, C23 to C30, with anteiso chains predominating, while the α‐hydroxy fatty acids were short chain C13 to C18 acids with C16 predominating. The sterols in diesters ωType I‐St were cholesterol (∼60%), Δ7 cholestenol (∼35%) and an unidentified compound (∼5%) with a GLC retention time slightly longer than Δ7 cholestenol on SE‐30 phase. The ω‐hydroxy fatty acids and α,ω‐diols both were of exceedingly long chain lengths, C29−C38, and showed similar GLC profiles. Two types of triesters comprising approximately 1% of total steer meibomian lipids have been isolated but incompletely characterized. In terms of molar ratios, one group of triesters gave fatty acids:ω‐hydroxy fatty acids:α‐hydroxy fatty acids:sterols + fatty alcohols as approximately 1∶1∶1∶1. The other contained fatty acids, α‐hydroxy fatty acids and α,ω‐diols in what appears to be a complex mixture of several triesters. Diesters ωType I and α,ωType II also were found in human meibum. Hitherto these two diesters have not been found in any animal tissue.
Need for an Individualized and Aggressive Management of Multinodular Goiters of Endemic Zones by Specially Trained Surgeons: Experience in Western Nepal
Authors: Baxi M. , Shetty K. J. , Baxi J. , Basu A. , Talwar O. P. , Smithi S. , Tiwari P. K. , Maudar K. K.
Published: November 2006

Background

The goals of the present study were to explore the presentation of multinodular goiter (MNG) and solitary thyroid nodules (STN) in the sub‐Himalayan belt, including the risk of malignancy, and to evaluate whether specialized surgeon training in endocrine surgery has an effect on reducing complications.

Methods

This retrospective study (1998–2003) analyzed 624 patients with thyroid disorders seen in the thyroid clinic of a tertiary care hospital in western Nepal. The findings included 67.7% (n = 423: euthyroid, 297, toxic, 126) multinodular goiters (MNG) and 18.5% (n = 116) STN. Rest of patients of other thyroid disorders were excluded from the study. Ultrasonography and fine‐needle aspiration cytology (FNAC) were the available diagnostic adjuncts. To evaluate the role of surgeon training, outcomes were compared between patients cared for by surgeons specially trained in endocrine surgery and those who were not. Prognostic markers indicated aggressiveness of cancers.

Results

Of the 539 MNG and STN patients in this series, 236 underwent operation. Of these, 25.7% (139/539) were toxic, and 11.31% had associated carcinoma. Aggressive cancers, like poorly differentiated (4.9%) and anaplastic types (18%), were more common than in series of patients from iodine‐sufficient regions. Patients 40–55 years of age were more likely to have toxicity, and those > 60 years of age were more likely to have aggressive cancers. Postoperative complication rates were lower in the group treated by surgeons who had special training in endocrine surgery.

Conclusions

There is a higher incidence of toxicity and malignancy in MNG in an endemic goiter zone. The limited diagnostic and therapeutic facilities in the region under study warrant a high degree of clinical suspicion and judgment, sound knowledge of thyroid physiology, thorough interpretation of hormone test results, and meticulous surgical techniques. The treatment must be individualized with consideration of humanitarian and socioeconomic factors, without compromising the quality of care and its long‐term consequences. Aggressive management of malignancy and toxicity with total thyroidectomy is needed as primary therapy in many instances. However, subtotal excision is more useful in carefully selected cases with a small remnant. Specialized training in thyroid surgery appears to be valuable in reducing complications.
Better the Devil You Know? High‐Risk Individuals’ Anticipated Psychological Responses to Genetic Testing for Melanoma Susceptibility
Authors: Kasparian Nadine A. , Meiser Bettina , Butow Phyllis N. , Job R. F. Soames , Mann Graham J.
Published: November 2006

Purpose: The psychological consequences of genetic testing for mutations among individuals at increased risk of developing melanoma remain unexamined. The present study aimed to explore anticipated emotional, behavioral, cognitive, and familial responses to hypothetical genetic testing for melanoma susceptibility. Methods: Forty semi‐structured interviews were undertaken with affected (n=20) and unaffected (n=20) individuals at either high or average risk of developing melanoma due to family history. Results: In‐depth thematic analysis revealed that, in response to being identified as a mutation carrier, most participants with a family history anticipated calmly accepting their increased risk; either increasing precaution adoption or maintaining already vigilant behavioral practices; perceiving such information as important and valuable; and communicating genetic test results to family members, despite the acknowledgement of potential difficulties. In response to being identified as a non‐carrier, the majority of participants expected to feel relieved; to maintain current precautionary health practices; to still perceive themselves at some risk of developing melanoma; and to be wary of the potential negative behavioral consequences of disclosing such information to family members. Women appeared more likely than men to acknowledge the potential for depression and worry following genetic testing. In contrast, more males than females expected to carry a gene mutation, and viewed their current preventive practices as optimum. Conclusion: Genetic testing for melanoma risk is likely to elicit a complex array of emotional, behavioral, cognitive, and familial responses for both testees and their family members, and these responses are likely to bear subtle differences for males and females.
If We Build It … Will They Come? – Establishing a Cancer Genetics Services Clinic for an Underserved Predominantly Latina Cohort
Authors: Ricker Charité , Lagos Veronica , Feldman Nancy , Hiyama Susan , Fuentes Sue , Kumar Visanth , Gonzalez Kelly , Palomares Melanie , Blazer Kathleen , Lowstuter Katrina , MacDonald Deborah , Weitzel Jeffrey
Published: November 2006

Background:Cancer genetic counseling and testing is a standard of care option for appropriate families and can identify individuals at increased risk prior to diagnosis, when prevention or detection strategies are most effective. Despite documented efficacy of cancer risk reduction in high‐risk individuals, underserved and minority individuals have a disproportionate cancer burden and limited access to genetic counseling.Methods:A needs assessment survey documented gaps in knowledge and interest in prevention. Satellite clinics were established at two indigent healthcare systems. Cancer genetics CME lectures were conducted and referral guidelines disseminated to clinicians who referred patients for counseling.Results:An increase in clinician knowledge was demonstrated post‐CME and reflected by quality referrals. Eighty‐eight percent of patients kept their appointments. In the predominantly Latina6(n=77) clinic population, 71.4% were affected with cancer, and 17 mutation positive families were identified. Preliminary data shows a positive impact on patients' motivation and behavior. The majority has expressed satisfaction and reduction in anxiety.Conclusions:This study demonstrates feasibility and acceptability of cancer genetics services in this population, suggesting the potential to reduce cancer morbidity in underserved, high‐risk families.
Generation of Entangled Two-Photon Binomial States in Two Spatially Separate Cavities
Authors: Lo Franco Rosario , Compagno Giuseppe , Messina Antonino , Napoli Anna
Published: November 2006

We propose a conditional scheme to generate entangled two-photon generalized binomial states inside two separate single-mode high-Q cavities. This scheme requires that the two cavities are initially prepared in entangled one-photon generalized binomial states and exploits the passage of two appropriately prepared two-level atoms one in each cavity. The measurement of the ground state of both atoms is finally required when they exit the cavities. We also give a brief evaluation of the experimental feasibility of the scheme.
Quantum Computation of Universal Link Invariants
Authors: Garnerone Silvano , Marzuoli Annalisa , Rasetti Mario
Published: November 2006

In the framework of the spin-network simulator based on the SU q(2) tensor algebra, we implement families of finite state quantum automata capable of accepting the language generated by the braid group, and whose transition amplitudes are coloured Jones polynomials. The automaton calculation of the polynomial of a link L on n strands at any fixed root of unity q is bounded from above by a linear function of the number of crossings of the link, on the one hand, and polynomially bounded in terms of the braid index n, on the other.
Microscopic Origin of Casimir-Polder Forces
Authors: Buhmann Stefan Yoshi , Safari Hassan , Welsch Dirk-Gunnar , Dung Ho Trung
Published: November 2006

We establish a general relation between dispersion forces. First, based on QED in causal media, leading-order perturbation theory is used to express both the single-atom Casimir-Polder and the two-atom van der Waals potentials in terms of the atomic polarizabilities and the Green tensor for the body-assisted electromagnetic field. Endowed with this geometry-independent framework, we then employ the Born expansion of the Green tensor together with the Clausius-Mosotti relation to prove that the macroscopic Casimir-Polder potential of an atom in the presence of dielectric bodies is due to an infinite sum of its microscopic many-atom van der Waals interactions with the atoms comprising the bodies. This theorem holds for inhomogeneous, dispersing, and absorbing bodies of arbitrary shapes and arbitrary atomic composition on an arbitrary background of additional magnetodielectric bodies.
Synthesis and phospholipase C inhibitory activity of D609 diastereomers
Authors: González‐Roura Albert , Casas Josefina , Llebaria Amadeu
Published: November 2006

The potassium xanthate D609 is widely accepted as a selective inhibitor of PC‐specific phospholipase C (PC‐PLC). The tricyclo[5.2.1.02,6]decane skeleton present in D609 can lead to four diastereomeric paris, but the diastereoselectivity of PC‐PLC inhibition has never been reported. In this article, the synthesis of racemic D609 diastereomers and that of other xanthates, as well as their inhibitory effect on PC‐PLC is reported. All xanthates obtained were competitive inhibitors of PC‐PLC from Bacillus cereus (PLCBc). No significant differences were found in the activity of D609 diastereomers (Ki 13–17 μM), suggesting the absence of a diastereochemical control of the enzyme by xanthate inhibitors. This result was confirmed after obtaining other potassium xanthates differing from D609 in the aliphatic chain. Among them, the potassium O‐n‐decenylxanthate was the most active inhibitor of PLCBc (Ki 10 μM). These data indicate that the essential structural requirements for PLCBc in vitro inhibition by xanthates are the presence of a Zn‐chelating dithiocarbonate head and a sufficiently hydrophobic aliphatic moiety.
Cloning and molecular characterization of the Δ6‐desaturase from two Echium plant species: Production of GLA by heterologous expression in yeast and tobacco
Authors: García‐Maroto Federico , Garrido‐Cárdénas José A. , Rodríguez‐Ruiz Juan , Vilches‐Ferrón Miguel , Adam Ana C. , Polaina Julio , López Alonso Diego
Published: November 2006

The synthesis of GLA (Δ6, 9, 12‐18:3) is carried out in a number of plant taxa by introducing a double bond at the Δ6 position of its precursor, linoleic acid (Δ9, 12‐18:2), through a reaction catalyzed by a Δ6‐desaturase enzyme. We have cloned genes encoding the Δ6‐desaturase (D6DES) from two different Macaronesian Echium species, E. pitardii and E. gentianoides (Boraginaceae), which are characterized by the accumulation of high amounts of GLA in their seeds. The Echium D6DES genes encode proteins of 438 amino acids bearing the prototypical cytochrome b5 domain at the N‐terminus. Cladistic analysis of desaturases from higher plants groups the Echium D6DES proteins together with other Δ6‐desaturases in a different cluster from that of the highly related Δ8‐desaturases. Expression analysis carried out in E. pitardii shows a positive correlation between the D6DES transcript level and GLA accumulation in different tissues of the plant. Although a ubiquitous expression in all organs is observed, the transcript is particularly abundant in developing fruits, whereas a much lower level is present in mature leaves. Functional characterization of the D6DES gene from E. gentianoides has been achieved by heterologous expression in tobacco plants and in the yeast Saccharomyces cerevisiae. In both cases, overexpression of the gene led to the synthesis of GLA. Biotechnological application of these results can be envisaged as an initial step toward the generation of transgenic oleaginous plants producing GLA.
Evidence for [1,5] sigmatropic rearrangements of CLA in heated oils
Authors: Destaillats Frédéric , Angers Paul
Published: November 2006

Linoleic acid was heated at 200°C under helium. Analysis of degradation products by GC on a long polar open tubular capillary column showed the presence of CLA isomers. The identified mono trans CLA isomers were cis‐9, trans‐11, trans‐9, cis‐11, trans‐10, cis‐12, cis‐10, trans‐12, trans‐8, cis‐10, and cis‐11, trans‐13 18:2 acids. Oils containing different levels of linoleic acid (peanut, sesame seed, and safflower seed oils) were also heat treated, resulting in similar CLA distributions. Elution order was confirmed using cis‐9, trans‐11 and trans‐10, cis‐12 acid methyl esters standards and their respective configuration isomers (trans‐9, cis‐11, cis‐10, trans‐12), obtained after mild selenium‐catalyzed isomerization. These results indicated that two conjugated mono trans isomers of 18:2 acid, cis‐8, trans‐10 and trans‐11, cis‐13 18:2 were absent from the series, thus strongly suggesting that some constraints were preventing their formation. By heating pure methyl rumenate (cis‐9, trans‐11 18:2) under similar conditions, isomerization resulted principally in a nearly equimolar mixture of methyl rumenate and trans‐8, cis‐10 18:2. Similarly, the methyl ester of trans‐10, cis‐12 18:2 acid was partially transformed into cis‐11, trans‐13 18:2 acid. Respective geometrical isomers were also formed in trace amounts. A concerted pericyclic isomerization mechanism, a [1,5] sigmatropic rearrangement, is proposed that limits the conjugated system to isomerization from a cis‐trans acid to a trans‐cis acid, and vice versa. This mechanism is consistent with undetected cis‐8, trans‐10 and trans‐11, cis‐13 18:2 isomers in heated oils containing linoleic acid.
Protective effect of oleuropein, an olive oil biophenol, on low density lipoprotein oxidizability in rabbits
Authors: Coni E. , Di Benedetto R. , Di Pasquale M. , Masella R. , Modesti D. , Mattei R. , Carlini E. A.
Published: November 2006

On the basis of the results obtained with pilot studies conducted in vitro on human low density lipoprotein (LDL) and on cell cultures (Caco‐2), which had indicated the ability of certain molecules present in olive oil to inhibit prooxidative processes, an in vivo study was made of laboratory rabbits fed special diets. Three different diets were prepared: a standard diet for rabbits (diet A), a standard diet for rabbits modified by the addition of 10% (w/w) extra virgin olive oil (diet B), a modified standard diet for rabbits (diet C) differing from diet B only in the addition of 7 mg kg−1 of oleuropein. A series of biochemical parameters was therefore identified, both in the rabbit plasma and the related isolated LDL, before and after Cu‐induced oxidation. The following, in particular, were selected: (i) biophenols, vitamins E and C, uric acid, and total, free, and ester cholesterol in the plasma; (ii) proteins, triglycerides, phospholipids, and total, free, and ester cholesterol in the native LDL (for the latter, the dimensions were also measured); (iii) lipid hydroperoxides, aldehydes, conjugated dienes, and relative electrophoretic mobility (REM) in the oxidized LDL (ox‐LDL). In an attempt to summarize the results obtained, it can be said that this investigation has not only verified the antioxidant efficacy of extra virgin olive oil biophenols and, in particular, of oleuropein, but has also revealed a series of thus far unknown effects of the latter on the plasmatic lipid situation. In fact, the addition of oleuropein in diet C increased the ability of LDL to resist oxidation (less conjugated diene formation) and, at the same time, reduced the plasmatic levels of total, free, and ester cholesterol (−15, −12, and −17%, respectively), giving rise to a redistribution of the lipidic components of LDL (greater phospholipid and cholesterol amounts) with an indirect effect on their dimesions (bigger by about 12%).