bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct imaging of spin‐reorientation transitions in ultrathin Ni films by spin‐polarized low‐energy electron microscopy
Authors: Klein C. , Ramchal R. , Farle M. , Schmid A. K.
Published: November 2006

The thickness‐dependent spin‐reorientation transition (SRT) in ultrathin Ni films grown on a stepped Cu(100) substrate was studied by spin‐polarized low‐energy electron microscopy (SPLEEM). Magnetic contrast in SPLEEM is proportional to the scalar product of beam polarization and magnetization of the film. This dependence was exploited to determine the local 3D magnetization vector by evaluating magnetic contrast in images obtained using three orthogonal polarizations of the incident electron beam. Using this method, we were able to directly image the rotation of the magnetization vector in Ni films from in‐plane and parallel to the steps to out‐of‐plane and perpendicular to the steps of the substrate. We found the SRT to proceed via two mechanisms: continuous growth of the out‐of‐plane component, accompanied by discontinuous reorientation of the in‐plane component via domain nucleation. Copyright © 2006 John Wiley & Sons, Ltd.
Light emission by surface plasmons on nanostructures of metal surfaces induced by high‐energy electron beams
Authors: Yamamoto N. , Nakano M. , Suzuki T.
Published: November 2006

Light emission by surface plasmons induced by high‐energy electron beams was investigated for several nanostructures, i.e. two touching particles of silver, a silver whisker and stripes on a flat metal surface. The emission spectra showed that the resonant peaks originated from the resonant modes of surface plasmons. Monochromatic photon maps taken at peak wavelengths clearly revealed the spatial distribution of surface plasmons on the metal nanostructures. Copyright © 2006 John Wiley & Sons, Ltd.
A novel approach to derive absorption coefficient of secondary electrons as applied to Ti and TiO2
Authors: Iyasu Takeshi , Inoue M. , Yoshikawa H. , Shimizu Ryuichi
Published: November 2006

A novel approach is proposed to derive a theoretical curve, δ(EP), from the equation

for construction of a database of the secondary electron emission (k, α), where δ(EP) and [dE/dz] are the secondary yield and energy dissipation in depth, respectively, for incident electrons of primary energy, EP. α is the absorption coefficient of the secondary electron and k the secondary emission coefficient of the specimen. This approach is based on the use of the theoretical energy dissipation in depth [dE/dz], which is to be obtained from Monte Carlo calculation, and the experimental δex(EP) or a set of δm and Em to be measured in experiment, where δm is the maximum secondary yield obtained at primary electron energy Em. Comparing the theoretical δ(EP) with the experimental δex(Ep) or a set of δm and Em one can obtain the best‐fit value of α and, then, k.

Since data‐sets of δm and Em have been reported for a wide variety of materials so far, the proposed approach enables us to derive the α and k values for the materials of practical interest, filling up the deficiency of reliable data on the secondary emission.

This approach was verified by applying it to Be, Ag, Pt and Bi, of which δm and Em have been published, leading to the confirmation that α‐values derived by the present approach agree very well with the experimental ones. Experiments was also performed to measure δ(EP) for Ti and TiO2 to obtain α and k‐values. The results are α−1≅0.5 nm and k≅0.046, for Ti, α−1≅0.7 nm and k≅0.028 for TiO2. Copyright © 2006 John Wiley & Sons, Ltd.
Characteristics of a cluster‐ion beam of Os3(CO)n+ (n = 7 or 8) for low‐damage sputtering
Authors: Fujiwara Yukio , Kondou Kouji , Teranishi Yoshikazu , Nonaka Hidehiko , Fujimoto Toshiyuki , Kurokawa Akira , Ichimura Shingo , Tomita Mitsuhiro
Published: November 2006

A cluster‐ion source has been developed to produce stable ion beams of metal‐cluster‐complex ions. As a metal cluster complex, triosmium dodecacarbonyl, Os3(CO)12, was used, which has a molecular weight of 906.7. Using the ion source, energy dependence of beam current and sputtering yield of silicon bombarded with Os3(CO)n+ (n = 7–8) were investigated at beam energies from 2 to 10 keV under the normal incidence condition. By high‐resolution Rutherford backscattering spectrometry (HR‐RBS), a silicon target bombarded with the normally incident Os3(CO)7–8+ ions at 10 keV with oxygen flooding at 5 × 10−4 Pa was analyzed. The experimental results showed that the ion‐beam current increased almost linearly with the acceleration voltage. It was found that the sputtering yields of silicon with Os3(CO)7–8+ ions varied substantially with beam energy. The sputtering yield with Os3(CO)7–8+ at 10 keV was higher than that with SF5+ or Ar+ by a factor of 3–20, whereas the yield at 3 keV was lower than that with Ar+. In the case of 2 keV, deposition was found to occur on the silicon surface. The substantial variation in the sputtering yield with beam energy would arise from the lower kinetic energy of each atom constituting the metal‐cluster‐complex ions. From HR‐RBS results, it was confirmed that the constituent atoms of the Os3(CO)7–8+ ions, Os, C, and O, were implanted into the silicon target. The observed depth profiles of Os and C atoms were in good agreement with results of TRIM simulation, while that of the O atom was significantly different from the simulation results. The depth profile of the O atom was examined in terms of oxygen diffusion and implantation. Copyright © 2006 John Wiley & Sons, Ltd.
Photoemission electron microscopy with chemical sensitivity: SPELEEM methods and applications
Authors: Locatelli A. , Aballe L. , Mentes T. O. , Kiskinova M. , Bauer E.
Published: November 2006

The instrumentation for synchrotron radiation X‐ray photoemission electron microscopy (XPEEM) has recently undergone significant improvements, finding application in diverse fields such as magnetism, chemistry, surface science and nanostructure characterization. The spectroscopic photoemission and low energy electron microscope (SPELEEM) operational at the ‘Nanospectroscopy beamline’ at the Elettra synchrotron facility combines structural and spectroscopic analysis methods in a single instrument, exploiting the inherent chemical sensitivity of X rays. The SPELEEM reaches an energy resolution of 0.2 eV and a lateral resolution of few tens of nanometers in XPEEM. Selected results are used to illustrate the spectro‐microscopic capabilities of the SPELEEM, and the usefulness of available complementary methods such as low energy electron microscopy (LEEM) and micro‐spot low energy electron diffraction (LEED). Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of GOI‐MOSFET with high‐kgate dielectric and metal gate fabricated by Ge condensation technique
Authors: Park Mungi , Bea Jicheol , Fukushima Takafumi , Koyanagi Mitsumasa
Published: November 2006

In order to improve the complementary metal‐oxide‐semiconductor (CMOS) circuit performance under sub‐100 nm technology nodes with low supply voltages, a metal‐oxide‐semiconductor field‐effect transistor (MOSFET) including a high mobility channel and a silicon‐on‐insulator (SOI) structure is a promising device design. According to The International Technology Roadmap for Semiconductors (ITRS), a 25‐nm MOSFET with a gate oxide equivalent oxide thickness (EOT) of 5–8 nm will be produced by 2010. Several groups have reported thermally stable gate dielectrics such as HfO2, ZrO2, HfxSi1−xO, HfOxNy, ZrOxNy, and Ln2O3. However, considering the relatively thick interfacial layer (∼0.5 nm SiOx) and the relatively low dielectric constant (10–20) of these materials, it is very difficult to scale down the EOT below 1 nm. In this paper, we report on the electrical characteristics of sputtered HfO2with an EOT of 0.78 nm. We report Ge metal‐insulator‐semiconductor field‐effect transistors (MISFETs) with HfO2and W/W2N metal gate electrode on germanium‐on‐insulator (GOI) wafer obtained by the new graded Ge condensation method. Excellent device characteristics are achieved with a subthreshold swing of 80 mV/dec and low gate leakage. Copyright © 2006 John Wiley & Sons, Ltd.
Study on the origin of the anisotropic dielectric properties of the Au‐adsorbed Si(001) vicinal surface
Authors: Minoda Hiroki , Yamamoto Naoki
Published: November 2006

A study on the origin of the anisotropic dielectric properties of Au‐adsorbed Si(001) vicinal surface was carried out by observation of the electron‐beam‐induced light emission from the Si(001) 5 × 3.2‐Au surface and the Au‐adsorbed Si(111) vicinal surface by using a light detection system combined with a transmission electron microscope. It was found that the polarization of the light emitted from steps of the Si(001)‐Au surface is different from that from the Si(001) 5 × 3.2‐Au surface, but is similar to that from the (119) facet in the case of the Au adsorbed Si(001) vicinal surface. The polarization depends on the numbers of steps, and the step bands that include a larger number of steps show higher polarization. The polarization of the emitted light from the Au‐adsorbed Si(111) vicinal surface is much weaker compared to that from the Au‐adsorbed Si(001) surface. These results suggest that the origin of the anisotropic dielectric properties of the Au‐adsorbed Si(001) vicinal surface is due to the anisotropy of the atomic structure of the surface. Copyright © 2006 John Wiley & Sons, Ltd.
Shave‐off depth profiling of dendritic short‐circuit growth caused by ion migration
Authors: Yamamoto T. , Maekawa A. , Ishizaki Y. , Tanaka R. , Owari M. , Nojima M. , Nihei Y.
Published: November 2006

The rapid progress made in recent years in the field of nanotechnology has been remarkable. In semiconductor devices, it has become increasingly important to evaluate the reliability of not only the device itself but also the connection between the circuit board and the device terminals. This is especially true for semiconductor device packages developed in response to the needs of high‐density mounting. Therefore, new problems of insulation degradation are anticipated during the advances of semiconductor device packaging. Ion migration is one of the problems. Although the classical model of ion migration has been well known for several decades, the details of the migration process in semiconductor device packages are still unknown. In this study, we have analyzed the dendritic short‐circuit growth of Cu caused by ion migration in semiconductor device packages using shave‐off depth profiling and TEM‐EDX. The highly sensitive and unique depth profiling has provided indispensable information for discussion on the mechanisms of the dendritic short‐circuit growth. Copyright © 2006 John Wiley & Sons, Ltd.
Improvement of a method for reconstructing the three‐dimensional atom probe (3DAP) data
Authors: Chiba T. , Nojima M. , Owari M.
Published: November 2006

A method for reconstructing the three‐dimensional atom probe (3DAP) data with cluster ions, which are composed of the so‐called undetected atoms, has been developed. The position and structure of clusters composed of undetected atoms may be determined by taking into account the number of atoms within a sphere that centers at a grid‐point set in the reconstructed 3DAP data. On the basis of the simulation data, it was demonstrated that the position of each undetected atom constituting a cluster with nine or fewer atoms could be determined using the method proposed. Copyright © 2006 John Wiley & Sons, Ltd.
Highly sensitive ion imaging system using direct combination of a stacked‐type solid‐state imager and a microchannel plate driven by LabVIEW software
Authors: Sakamoto Naoya , Yurimoto Hisayoshi
Published: November 2006

A direct ion imaging system with single ion detection and high‐precision imaging modes has been developed. This system is composed of a movable microchannel plate unit and a stacked CMOS‐type active pixel sensor (SCAPS). Capabilities of single ion detection were evaluated by ion irradiations using secondary ion mass spectrometry. The experiment shows that this system accurately detected single incident ions. Copyright © 2006 John Wiley & Sons, Ltd.
In situ scanning electron microscopy of single‐walled carbon nanotube growth
Authors: Takagi Daisuke , Homma Yoshikazu , Suzuki Satoru , Kobayashi Yoshihiro
Published: November 2006

We have developed an in situ observation technique for chemical vapor deposition (CVD) of single‐walled carbon nanotubes (SWNTs) using a scanning electron microscope (SEM). The growth of SWNTs in the SEM is achieved by employing low‐pressure ethanol vapor as the carbon source and cobalt as the catalyst. The time evolution of SWNT growth is successfully traced by alternate CVD growth in low vacuum and SEM observation in high vacuum. By limiting the nanotube growth areas, individual SWNT growth could be observed. Copyright © 2006 John Wiley & Sons, Ltd.
Stable multiwalled carbon nanotube electron emitter operating in low vacuum
Authors: Suga Hiroshi , Abe Hidekazu , Tanaka Miyuki , Shimizu Tetsuo , Ohno Teruaki , Nishioka Yasushiro , Tokumoto Hiroshi
Published: November 2006

We have investigated field emission (FE) properties of an individual multiwalled carbon nanotube (CNT) under low‐vacuum regions around 10−3 Pa. Current versus voltage characteristics of the present CNT emitters were found to be explicable on the basis of the Fowler–Nordheim (F–N) formalism. Time trace of the FE current exhibited more than 30% fluctuation about the mean value, and the lifetime was less than 5 h. Scanning electron microscopy (SEM) observation elucidated that the lengths of the CNTs were reduced after prolonged field emission, plausibly because of local heating induced by the large current density at the apex. To prolong the lifetime, we attempted a type of feedback system by inserting a high ohmic resistance between the electron emitter and the power supply. As a result, the current fluctuation decreased from ∼30% to 2% at 0.1 µA, and the lifetime increased from 5 to 50 h. Finally, an SEM was equipped with both the emitter systems, with and without resistance, which were designed for the CNT field emitter. The SEM images taken by using the emitter with resistance showed consistently brighter appearance, whereas those taken without the resistance exhibited fluctuations in the image brightness. Copyright © 2006 John Wiley & Sons, Ltd.
Sb on In/Si(111) processes with dynamically observable LEEM, selected area LEED and chemically analyzed SR‐XPEEM
Authors: Nakaguchi A. , Guo F.‐Z. , Hashimoto M. , Ueda M. , Yasue T. , Matsushita T. , Tamenori Y. , Kinoshita T. , Kobayashi K. , Koshikawa T.
Published: November 2006

Sb adsorption processes on In/Si(111) √3 × √3 and √31 × √31 surfaces were investigated in the present work. The dynamic growth behavior was observed with low energy electron microscopy (LEEM), and the local surface structure change was monitored with selected area low energy electron diffraction (LEED). X‐ray generated photo emission electron microscopy using synchrotron radiation (SR‐XPEEM) was employed in order to see the variation of the chemical state on the surface. On both √3 × √3 and √31 × √31 surfaces, Sb adsorption induces the surface structural change and modifies the chemical interaction of In atoms with Si. In atoms are replaced by impinged Sb atoms, and the discharged In atoms form islands. Copyright © 2006 John Wiley & Sons, Ltd.
Bayesian estimation of false‐negative rate in a clinical trial of sentinel node biopsy
Authors: Newcombe Robert G.
Published: November 2006

Estimating the false‐negative rate is a major issue in evaluating sentinel node biopsy (SNB) for staging cancer. In a large multicentre trial of SNB for intra‐operative staging of clinically node‐negative breast cancer, two sources of information on the false‐negative rate are available.

Direct information is available from a preliminary validation phase: all patients underwent SNB followed by axillary nodal clearance or sampling. Of 803 patients with successful sentinel node localization, 19 (2.4 per cent) were classed as false negatives.

Indirect information is also available from the randomized phase. Ninety‐seven (25.4 per cent) of 382 control patients undergoing axillary clearance had positive axillae. In the experimental group, 94/366 (25.7 per cent) were apparently node positive. Taking a simple difference of these proportions gives a point estimate of −0.3 per cent for the proportion of patients who had positive axillae but were missed by SNB. This estimate is clearly inadmissible.

In this situation, a Bayesian analysis yields interpretable point and interval estimates. We consider the single proportion estimate from the validation phase; the difference between independent proportions from the randomized phase, both unconstrained and constrained to non‐negativity; and combined information from the two parts of the study. As well as tail‐based and highest posterior density interval estimates, we examine three obvious point estimates, the posterior mean, median and mode. Posterior means and medians are similar for the validation and randomized phases separately and combined, all between 2 and 3 per cent, indicating similarity rather than conflict between the two data sources. Copyright © 2006 John Wiley & Sons, Ltd.
Multilayered Si/Ni Nanosprings and Their Magnetic Properties
Authors: He Yuping , Fu Junxue , Zhang Yang , Zhao Yiping , Zhang Lijiao , Xia Ailin , Cai Jianwang
Published: November 2006

A two‐turn, eight‐armed, rectangular Si/Ni heterogeneous nanospring structure on Si(100) has been fabricated using a multilayer glancing‐angle deposition technique. The multilayered nanosprings with a height of ≈1.98 μm were composed of alternating layers of amorphous Si nanorods ≈580 nm in length and face‐centered cubic Ni nanorods ≈420 nm in length, both with a diameter of ≈35 nm. The magnetic anisotropy of the nanosprings showed that the in‐plane easy and hard axes were parallel and perpendicular to the Ni nanorod plane, respectively. The out‐of‐plane magnetic hysteresis loop was very sensitive to the applied magnetic field direction when rotating the nanosprings about their in‐plane hard axis, and the magnetization measurement revealed that the nanosprings tilted at ≈7.5° toward the plane of the Si nanorods. The magnetic anisotropy of the nanosprings is determined by their structure, and the experimental results can be interpreted by the shape anisotropy energy.
Supporting older youth: What's policy got to do with it?
Authors: Yohalem Nicole , Wilson‐Ahlstrom Alicia , Ferber Thaddeus , Gaines Elizabeth
Published: November 2006

State and local policy innovations that promote increased investments in institutions, community programs, and youth services are developing across the country and can inform out‐of‐school‐time strategies for older youth.
Ageing in yeast does not enhance prion generation
Authors: Shewmaker Frank , Wickner Reed B.
Published: November 2006

The yeast prions [URE3] and [PSI+] are self‐propagating amyloids of Ure2p and Sup35p, respectively. The analogous transmissible spongiform encephalopathies of mammals and other amyloidoses are largely diseases of later life. From normal strains lacking the prions, we isolated old cells and measured the frequency of de novo [URE3] and [PSI+] prion generation. We find no evidence that ageing of yeast increases the frequency of prion occurrence. Copyright © 2006 John Wiley & Sons, Ltd.
Substrate‐inducible versions of internal alternative NADH : ubiquinone oxidoreductase from Yarrowia lipolytica
Authors: Garofano Aurelio , Eschemann Andrea , Brandt Ulrich , Kerscher Stefan
Published: November 2006

In standard laboratory strains of the obligate aerobic yeast Yarrowia lipolytica, respiratory chain complex I (proton‐translocating NADH : ubiquinone oxidoreductase) is an essential enzyme, since alternative NADH dehydrogenase activity is located exclusively at the external face of the mitochondrial inner membrane. Deletions and other loss‐of‐function mutations in genes for nuclear coded subunits of complex I can be obtained only when an internal version of the latter enzyme, termed NDH2i, is introduced. In contrast to recent findings with Neurospora crassa, external alternative NADH dehydrogenase activity is dispensable in complex I deletion strains of Y. lipolytica. We used regulable promoters to create strains which express internal alternative NADH dehydrogenase in a substrate‐dependent manner. The ability to switch between complex I‐dependent and ‐independent mode of growth simply by changing the carbon source is an important prerequisite for screens for both loss‐of‐function and inhibitor resistance mutation. The isocitrate lyase promoter (pICL1), in combination with a NDH2i allele that results in reduced expression and activity, was most promising. In the presence of complex I inhibitors, this construct allowed growth on acetate, but not on glucose minimal media. A somewhat higher background was observed with the acyl‐CoA oxidase 2 (pPOX2) promoter on glucose minimal media. Copyright © 2006 John Wiley & Sons, Ltd.
In vitro characterization of the Mig1 repressor from Saccharomyces cerevisiae reveals evidence for monomeric and higher molecular weight forms
Authors: Needham Patrick G. , Trumbly Robert J.
Published: November 2006

The Mig1 DNA‐binding protein of Saccharomyces cerevisiae was expressed and purified from yeast and the physical properties were characterized by several methods, including gel filtration, sucrose gradient sedimentation and native gel electrophoresis. Purified Mig1 exists as a monomer with a Stokes' radius of 48 Å and a sedimentation coefficient of 3.55 S. Mig1 has an elongated shape with a frictional coefficient of 1.83. The Kd of purified Mig1 for the SUC2 A site is 2.8 nM and for SUC2 B site 25.8 nM; these values were similar for Mig1 purified from repressed and derepressed cells. Full‐length Mig1 expressed in yeast binds more tightly to SUC2 B than bacterially expressed GST–Mig1. Sucrose gradient sedimentation resolved a larger molecular weight form of Mig1 in whole‐cell extracts that was not seen in purified samples and may represent a complex with another protein. This complex is found within the nucleus and is seen only in repressed cells. Mig1 exists in multiple phosphorylation states and only less phosphorylated forms of Mig1 are associated with this complex. Copyright © 2006 John Wiley & Sons, Ltd.
Glyceryl ether, wax ester and triglyceride composition of the mouse preputial gland
Authors: Sansone Gail , Hamilton James G.
Published: November 2006

Major lipid classes of the preputial gland of the mouse have been identified as wax ester, neutral plasmalogen, glyceryl ether diester and triglyceride. The chain lengths and degree of unsaturation in the aliphatic moieties of the alk‐1‐enyl and alkyl glyceryl ethers are similar to those of the fatty alcohols of the wax ester fraction. This lends support to the theory that long chain fatty alcohols can be direct precursors of the aliphatic chains of glyceryl ethers. The striking qualitative, as well as quantitative, similarities between the alkyl and alk‐1‐enyl moieties of the glyceryl ethers in the neutral lipid fraction suggest that they share a common pathway of biosynthesis or are interconvertible. Neutral plasmalogens and glyceryl ether diesters contain significant amounts of odd‐numbered and branched fatty acids, unlike the fatty acids of the triglycerides; therefore, the biosynthesis of neutral plasmalogens and glyceryl ether diesters may not be related to the biosynthesis of triglycerides.
Lecithin‐protein interaction in the GTP‐dependent acyl‐CoA synthase
Authors: Galzigna Lauro , Sartorelli Lodovico , Rossi Carlo R. , Gibson David M.
Published: November 2006

The enzymic activity of the GTP‐dependent acyl‐CoA synthase isolated from rat liver mitochondria is affected by removal and addition of lecithin (3). Purified preparations of this enzyme contain bound lecithin. In this presentation the nature of the lecithin‐protein interaction is examined. From binding measurements at different temperatures it is possible to postulate which type of secondary valence bonds is holding the protein and lecithin together.
Preparation of14C‐labeled fatty and anacardic acids fromGinkgo biloba
Authors: Gellerman Joanne L. , Schlenk Hermann
Published: November 2006

Acetate labeled with14C was infused into shoots of Ginkgo. Up to 16% of the radioactivity was incorporated into lipids. Most of it was found in the leaves and stems, but after 9 days, the lipids of roots also contained an appreciable amount of radioactivity. Radioactive palmitic, linoleic and other common acids were isolated as methyl esters; 5,11,14–20∶3 and esters of similar type were isolated pure or together with their isomers of normal structure; anacardic acids were separated as such from the fatty esters.
The distribution and excretion of tritium labeled cerebroside (galactosyl ceramide) radioactivity by the monkey
Authors: Burton Robert Main , Lewis Walter , Sodd Mary Ann
Published: November 2006

Tritium labeled galactosyl ceramide was administered intravenously to three male monkeys (Macaca mulatta). Blood, urine, feces and organs obtained at autopsy were examined for radioactivity after 1 hr, 8 hr and 37 days. The radioactive galactosyl ceramide was taken up by the reticuloendothelial system. Very little radioactivity appeared in brain tissue. The radioactivity was excreted primarily in urine.
Essential fatty acid‐deficient rats: III. Distribution of lipid classes in rat testes after feeding partially hydrogenated oils
Authors: Hølmer G. , Aaes‐Jørgensen E.
Published: November 2006

Total and relative amounts of neutral lipids (NL) and phospholipids (PL) as well as the distribution of various lipid classes in these were determined in testes of rats fed different types of partially hydrogenated oils for 5,15 and 26 weeks. The dietary fats were partially hydrogenated arachis oil (HAO), partially hydrogenated soybean oil (HSO), partially hydrogenated herring oil (HHO) and, for comparison, arachis oil (AO). An additional series of animals was reared on a fat‐free diet throughout the entire experiment. The total amount of NL is decreased by EFA deficiency parallel with the development of the degenerative changes of the spermatogenic tissue. The relative amounts of NL in the testis are not influenced by EFA deficiency during the first stages of degeneration. However, feeding of HHO for 26 weeks resulted in a marked decrease in NL. The total content of PL is directly related to tissue degeneration. This observation is supported by the data obtained after 5 weeks of feeding HHO and by the correspondence between the results found after 15 and 26 weeks on HAO and the fat‐free diets, respectively. The relative amount of PL is less influenced by EFA deficiency, but severe degenerations as found for the group fed HHO are followed by decreases. The neutral lipids had three main fractions: triglycerides (TG), free fatty acids (FFA) and cholesterol (Chol). FFA was found to be the main fraction of NL after 5 weeks, whereas TG was the main component of NL after 15 and 26 weeks, especially in the animals with degenerated testes. The presence of the large quantities of FFA is discussed. Cholesterol was decreased markedly in the EFA deficient rats fed partially hydrogenated oils, but not in the fat‐free reared groups. The variations in the PL distribution during the experiment were small with regard to the two main PL classes, the phosphatidylcholines and the phosphatidylethanolamines. The most remarkable change among the PL classes was an increase in the percentage of sphingomyelins when the spermatogenic degenerations developed.
Biosynthesis of glycolipids: Incorporation of N‐acetyl galactosamine by a rat brain particulate preparation
Authors: Handa Shizuo , Burton Robert M.
Published: November 2006

A mixture of UDP‐(N‐acetyl)glucosamine‐114C and UDP‐(N‐acetyl)galactosamine‐114C (7∶3) served as a substrate to demonstrate in young rat brain tissue the presence of enzymes which catalyzes the reactions: UDP‐glcNAc⇌UDP‐galNAc (E.C.5.1.3) and UDP‐galNAc+ gal‐glc‐cer→ galNAc‐gal‐glc‐cer+UDP. The glycolipid acceptor specificity was examined and preliminary kinetic data were obtained for the UDP‐(N‐acetyl)galactosamine: gal‐glc‐ceramide N‐acetyl galactosamine transferase. The products of the reaction were identified. The relationship of this reaction to ganglioside biosynthesis is discussed.
9,12,15‐octadecatrien‐6‐ynoic acid, new acetylenic acid from mosses
Authors: Åndersson Bengt , Anderson Wayne H. , Chipault Jacques R. , Ellison Eldon C. , Fenton Stuart W. , Gellerman Joanne L. , Hawkins John M. , Schlenk Hermann
Published: November 2006

Lipids of the moss,Ceratodon purpureus, yield up to 25% of an acetylenic acid which was identified as allcis‐9,12,15‐octadecatrien‐6‐ynoic acid. The methyl ester of this acid was isolated in 95% purity by gas liquid chromatography. Mass spectroscopy provided the mol wt and confirmed methyl stearate as product of hydrogenation. Ozonization indicated a triple bond in position 6 and a double bond in position 15. UV and IR spectra showedcis‐double bonds, no conjugation, and notrans‐double bonds. The Raman spectrum provided direct evidence for the triple bond and confirmed the presence of double bonds and the absence of conjugation. The ratio of intensities indicated 1 triple bond/3 double bonds. 9,12,15‐Octadecatrien‐6‐ynoic acid has not previously been isolated from biological materials. It was found only in the triglycerides ofCeratodon purpureus and several other mosses. In contrast to arachidonic and eicosapentaenoic acids, the acetylenic acid seems to be restricted to few moss genera.
Recent progress in the biochemistry of plant steroids other than sterols (Saponins, glycoalkaloids, pregnane derivatives, cardiac glycosides, and sex hormones)
Authors: Heftmann Erich
Published: November 2006

Recent studies concerning the biosynthesis, metabolism, and possible functions of steroids other than sterols in plants are reviewed and discussed. These studies embrace the saponins, glycoalkaloids, pregnane derivatives, cardiac glycosides, as well as their aglycones, and the sex hormones.
Pyrrolidides for mass spectrometric determination of the position of the double bond in monounsaturated fatty acids
Authors: Andersson Bengt A. , Holman Ralph T.
Published: November 2006

Mass spectra of pyrrolidides of monounsaturated straight chain fatty acids are presented and discussed. The spectra of pyrrolidides contain mainly ions from the polar part of the molecule. This gives simple spectra from which double bond positions can be deduced directly. If an interval of 12 atomic mass units is observed between the most intense peaks of clusters of fragments containing n and n−1 carbon atoms of the acid moiety, the double bond occurs between carbons n and n+1 in the molecule This rule is valid for double bonds occurring at positions Δ5‐Δ15 in an 18‐carbon chain and has been applied to acids having 10–24 carbon atoms.
Effect of dietary saturated fatty acids and linoleic acid upon the structures of triglycerides in rabbit tissues
Authors: Christie W. W. , Moore J. H. , Gottenbos J. J.
Published: November 2006

Five groups of rabbits were given a diet supplemented with safflower seed oil and safflower seed oil partially replaced by lauric, myristic, palmitic, and stearic acids respectively. After 10 weeks, plasma samples were taken from the animals in the fasted and nonfasted state; the animals then were killed, and the livers and samples of adipose tissue were removed. Lipids were extracted from the tissues, then separated into classes; and the fatty acid composition of each class was determined. In addition, the triglycerides were isolated and the structures determined by stereospecific analysis. There were marked differences in the compositions and structures of the triglycerides in the plasma from fasted and nonfasted animals. Feeding specific dietary fatty acids also greatly changed the metabolism of linoleic acid by the animals. The results are discussed in terms of the biosynthesis of triglycerides in plasma, liver, and adipose tissue.
Identification of methyl‐branched fatty acids from the triacylglycerols of subcutaneous adipose tissue of lambs
Authors: Smith A. , Calder A. G. , Lough A. K. , Duncan W. R. H.
Published: November 2006

A concentrate of branched chain fatty acids (as methyl esters) was prepared from the triacylglycerols of subcutaneous adipose tissue lipids of lambs receiving a carbohydrate‐rich (cereal) diet. This was accomplished by procedures which allowed the removal of unsaturated components by peroxidation and straight chain saturated components by urea‐adduct formation. The concentrate was analyzed by high resolution gas chromatography in combination with mass spectrometry and was shown to consist of a complex mixture of saturated methyl‐substituted fatty acids. Methyl substitution occurred on even‐numbered carbon atoms (relative to the carboxyl group) and the chain lengths of the acids ranged from 10 to 18 carbon atoms. Acids with one methyl substituent in the fatty acyl chain were most abundant; di‐, tri‐ and tetramethyl‐substituted acids were also present. The biosynthesis of these methyl‐substituted acids is discussed briefly.
Effects of cold stress on rats fed different levels of docosenoic acids
Authors: Darnerud P. O. , Olsen M. , Wahlström B.
Published: November 2006

Male Sprague‐Dawley rats, 4 weeks old, were subjected to an ambient temperature of 4 C for periods up to 24 days and fed a synthetic diet containing one of the following oils: peanut oil (PO), rapeseed oil (RO), low erucic acid rapeseed oil (LO), and partially hydrogenated marine oil (HO), each at 20% w/w. A parallel experiment using the same oils was performed at room temperature (23 C). During cold stress, animals on the RO diet showed higher mortality than all other groups; all 20 animals in this group died within 5 days. At room temperature, however, all animals survived. The lipid accumulation in the heart reached its peak in all groups after 3 days and then gradually declined. The accumulation was most pronounced in the RO animals and coincided with the high mortality at 4 C. The fatty acid composition of the cardiac triglycerides reflected that of the diet, while the composition of the cardiac lecithin was only marginally modified.
Lipogenesis in iron‐deficient adult rats
Authors: Sherman Adria Rothman
Published: November 2006

Iron‐deficient (5 ppm Fe) or control (307 ppm Fe) diets were fed ad libitum to female rats for 7 weeks, and then meal‐fed for 4 weeks. Body weights, hemoglobin levels, and hematocrits were lower (p<0.01) in deficient group (184±7, 7.1±0.4, 32.7±0.6) than in the control group (220±10, 16.9±0.3, 51.8±0.8) at the end of the 11‐week experiment. Animals were killed 1 hr after meal feeding, and liver slices, mesenteric adipose tissue, and segments of mid‐jejunum were incubated in vitro with [U‐14C] glucose or3H2O. Adipose tissue from deficient rats had incorporation of [U‐14C] glucose into triglycerides two to three times greater than control rats (p<0.01). Release of14CO2 from glucose was greater in adipose tissue of deficient rats than controls (p<0.05). Incorporation of3H2O into triglycerides was also two to three times greater in deficient adipose tissue than in controls (p<0.02). In liver slices, incorporation of glucose in polar lipids was slightly higher in deficient rats than in control rats (p<0.05). No significant differences were found in incorporation of3H2O or [U‐14C] glucose into lipids or CO2 in jejunum. Thus, iron‐ deficient adult rats have greater lipid synthesis from3H2O and glucose in adipose tissue than rats fed adequate levels of iron.
Uropygian gland alkane diol diesters in theKn mutation of the domestic chicken
Authors: Walker H. E. , Somes R. G.
Published: November 2006

Uropygial glands from chickens which are know to have theKn gene secrete qualitatively the same types of alkane diol diesters as the normal domestic chicken. However, there are many significant differences in the mole percent of individual fatty acids and diols within the diester between the two genetic types of chickens. In general, the mutant chickens have lesser amounts of the shorter chain fatty acids and diols and greater amounts of the longer chain fatty acids and diols. There is also a gene dosage effect with two mutant genes having a greater effect in many cases than a single mutant gene.
Incorporation of [1‐14C] acetate into lipids of soybean cell suspensions
Authors: Wilson A. C. , Kates M. , de la Roche A. I.
Published: November 2006

Suspension cultures of soybean cells incorporated [1‐14C] acetate very rapidly into the fatty acid moieties of phospholipids and glycolipids when incubated at 26 C for up to 22 hr. The most rapidly labeled lipid was 3‐sn‐phosphatidylcholine, which contained 58% of the total fatty acid radioactivity after 16 min; more than 75% of this label was found to be in the oleic acid of the phosphatidylcholine. After longer periods of incubation, the proportion of14C label decreased exponentially in phosphatidylcholine and increased markedly in an unidentified phospholipid (tentatively,bis‐phosphatidic acid), di‐ and triacylglycerols, and glycolipids. The proportion of radioactivity in oleic acid also decreased exponentially, accompanied by increases in linoleic acid first and then in linolenic acid. Most of the labeled linolenic acid at 22 hr was found in the unidentified phospholipid, di‐ and triacylglycerols, and the glycolipid fraction.
Thermal decomposition of methyl oleate hydroperoxides and identification of volatile components by gas chromatography‐mass spectrometry
Authors: Selke E. , Frankel E. N. , Neff W. E.
Published: November 2006

The role of methyl oleate hydroperoxides as precursors of volatile compounds was investigated by thermal decomposition in the injector port of a gas chromatograph attached to a computerized mass spectrometer. The major volatile compounds identified correspond to those formed from triolein heated in air at 192 C.
Prevention of obesity in Avy/a mice by dehydroepiandrosterone
Authors: Yen Terence T. , Allan Jean A. , Pearson Donovan V. , Action June M. , Greenberg Mark M.
Published: November 2006

Dehydroepiandrosterone, a mammalian glucose‐6‐phosphate dehydrogenase inhibitor, preventedAvy/a mice from becoming obese. Decreased accumulation of triacylglycerol accounted for a large portion of the weight difference between treated and controlAvy/a mice. Hepatic lipogenesis as measured by3H2O incorporation into total lipid was less in the dehydroepian drosterone‐treated mice. Dehydroepiandrosterone did not suppress appetite and had no apparent toxic effects at the doses used, and its weight controlling effects were reversible upon withdrawal of treatment.
Calcium activation of peanut lipoxygenase
Authors: Nelson M. S. , Pattee H. E. , Singleton J. A.
Published: November 2006

Peanut lipoxygenase isozyme 1 (pH optimum, 8.3) was strongly activated by 0.5–1.0 mM Ca++, and the rate of activation was maximum when the ratio of substrate to Ca++ was ca. 2∶1. Peanut lipoxygenase isozymes 2 and 3 (pH optima, 6.2) were activated by calcium but did not have an optimum level of activity. Calcium differentially activated peanut lipoxygenase causing the rate of pentane production to increase much more rapidly than the rate of oxygen consumed by the enzyme reaction. At pH 6.2, in the absence of calcium, the percentages of the hydroperoxide isomers produced by peanut lipoxygenase were 74.9% 13‐hydroperoxycis‐9,trans‐11‐octadecadienoic acid (13 LOOHcis‐trans), 2.6% 13‐hydroperoxytrans‐9,trans‐11‐octadecadienoic acid (13 LOOHtrans‐trans) and 22.5% 9‐hydroperoxy 10, 12‐octadecadienoic acid (9 LOOH). The presence of 1 mM Ca++ at pH 6.2 did not significantly affect the percentage distribution of the hydroperoxides produced. However, at pH 8.3, the percentage distribution of hydroperoxides produced was 45.2% 13 LOOHcis‐trans, 10.9% 13 LOOHtrans‐trans and 43.9% 9 LOOH in the absence of Ca++ and 57.0% 13 LOOHcis‐trans, 8.0% 13 LOOHtrans‐trans and 35.0% 9 LOOH in the presence of 1 mM Ca++.
Dietary control of the chain elongation of palmityl‐CoA in rat liver microsomes
Authors: Kawashima Y. , Suzuki Y. , Hashimoto Y.
Published: November 2006

The rate of chain elongation of palmityl‐CoA to stearyl‐CoA in rat liver microsomes was studied in connection with the nutritional status of the rats. The microsomal chain elongation activity, which had been decreased by starvation for 48 hr, was rapidly increased to a high level on refeeding. The apparent Km value for malonyl‐CoA in both normal and refed rats was the same, 1.2×10−4 M. Both cycloheximide and actinomycin D prevented the induction of microsomal chain elongation activity which was associated with refeeding. In addition, the activity of acyl‐CoA hydrolase and the rates of esterification of acyl‐CoA into phospholipids and neutral lipids in microsomes were not changed by the dietary alteration. These results support the conclusion that changes of the activity of microsomal chain elongation of palmityl‐CoA in various nutritional status result from a rapid synthesis of new enzyme(s).
The preparation, gas liquid chromatography, and some physical and chemical properties of certain higher aliphatic 2,4‐diketones—A new lipid class
Authors: Douglas Donald Edward , Francis Lyman Elwood
Published: November 2006

Fourteen saturated aliphatic 2,4‐diketones, ranging in chain length from C7 to C25, and one unsaturated compound, Δ12‐2,4‐heneicosenedione, were prepared by Claisen acylations of the appropriate methyl ketones, and their gas chromatographic behavior was studied. Mixtures of these diketones were resolved on columns containing UCW98 or Carbowax 20M stationary phases. Their methoxime and 2,4‐dinitrophenylsemicarbazone derivatives were resolved on OV‐17 and OV‐1 stationary phases, respectively. Since higher homologous aliphatic 2,4‐diketones have been found in mammalian tissues, they constitute a new lipid class.
Arylsulfonate esters of fatty alcohols as hypocholesterolemic agents. I: Oleyl and linoleyl p‐toluenesulfonates
Authors: Quackenbush Forrest W. , Rand Phillip G. , MacNintch John E.
Published: November 2006

Cholesterol levels of both plasma and liver of cholesterol‐fed rats are lowered by feeding linoleyl and oleyl esters of p‐toluenesulfonic acid. A structural specificity exists, since the effect is not observed with similar amounts of sodium p‐toluenesulfonate nor with linoleyl methanesulfonate. Effective levels of these arylsulfonates do not alter liver to body weight ratios and maturation, nor reduce plasma cholesterol in normocholesterolemic rats.
Determination of free choline and phosphorylcholine in rat liver
Authors: Barak Anthony J. , Tuma Dean J.
Published: November 2006

A simple procedure for the determination of levels of free choline and phosphorylcholine in hepatic tissue is outlined. The method makes use of the enzyme acid phosphatase to liberate choline from phosphorylcholine and incorporates the ability of choline to react with potassium triiodide to yield choline periodide for the measurement of choline and phosphorylcholine in liver. The method is accurate for both entities (recovery of 97–100% for choline and 92–98% for phosphorylcholine). For phosphorylcholine, the method is markedly simpler than other methods previously described and the results for normally fed rats are of the same order of magnitude. The applicability of the method was shown when it was demonstrated that diets containing different amounts of choline influenced the level of choline and phosphorylcholine in liver.
Substrate selectivity of diacylglycerol kinase in guinea pig brain
Authors: Holub B. J. , Piekarski J.
Published: November 2006

The present study was conducted to test the selectivity of the microsomal diacylglycerol kinase (ATP:1,2‐diacyl‐sn‐glycerol phosphotransferase) from guinea pig brain towards different 1,2‐diacyl‐sn‐glycerols. The molecular species added to the incubation medium as substrates were a mixture of the 1‐[3H]palmitoyl plus 1‐[14C]stearoyl homologs of either the monoenoic (2‐oleoyl), dienoic (2‐linoleoyl), tetraenoic (2‐arachidonoyl), or hexaenoic (2‐docosahexaenoyl) diacylglycerols. Rates of phosphatidic acid synthesis (1‐palmitoy plus 1‐stearoyl homologs) with each of the four classes of unsaturated diacylglycerols were not greatly different, although they were moderately higher in the case of the monoenes. No marked enzyme selectivity for either the 1‐palmitoyl or 1‐stearoyl homolog of the various 1‐saturated 2‐unsaturated diacylglycerols was apparent. Generally similar results were obtained with the diacylglycerol kinase in rat brain microsomes.
Accumulation of surfactant phospholipids in lipid pneumonia induced with methylnaphthalene
Authors: Taki Takao , Nakazima Tomoko , Emi Yohko , Konishi Yohichi , Hayashi Akira , Matsumoto Makoto
Published: November 2006

Lipid analyses were carried out on the lungs of female B6C3F1 mice treated with methylnaphthalene. Cholesteryl ester, which could not be detected in lungs of control animals, was present in lungs of treated animals. Cholesterol and dipalmitoyglycerophosphocholine (DPPC) content was increased about five times in lungs of treated mice compared with control mice, and the content of a minor phospholipid was increased six times. The latter phospholipid was purified by high performance liquid chromatography and identified as phosphatidylglycerol by thin layer chromatography and by fast atom bombardment‐mass spectrometry. Both DPPC and phosphatidylglycerol are known to be pneumonal surfactants produced from type II pneumocytes. Therefore, the accumulation of these lipids in lung tissue was assumed to be caused by the proliferation of type II cells induced by the administration of methylnaphthalene. The results provide important information concerning the underlying mechanism of endogenous lipid pneumonia in mice.
Fatty acids in echinoidea: Unusualcis‐5‐olefinic acids as distinctive lipid components in sea urchins
Authors: Takagi Toru , Kaneniwa Masaki , Itabashi Yutaka , Ackman R. G.
Published: November 2006

Open tubular gas liquid chromatographic (GLC) analyses of fatty acids from total lipids of 12 species of Echinoidea collected at several locations along the Pacific coast of Japan showed the same unusualcis‐5‐olefinic acids in all species, i.e.,cis‐5‐octadecenoic acid (5–18∶1),cis‐5‐eicosenoic acid (5–20∶1), all‐cis‐5,11‐ and 5,13‐eicosadienoic acids (5,11‐ and 5,13–20∶2), allcis‐5,11,14‐eicosatrienoic acid (5,11,14–20∶3) and all‐cis‐5,11,14,17‐eicosatetraenoic acid (5,11,14,17–20∶4). The structural analysis of partially purified 5,11,14,17–20∶4 was undertaken by reductive ozonolysis with GLC and gas chromatographic‐mass spectrometric analyses of the products.13C‐Nuclear magnetic resonance analyses of the totals and fractions of fatty acid methyl esters from the sea urchin lipids did not show any occurrence of fatty acids having an isolated olefinic bond in the 2, 3 or 4 positions. The 5‐olefinic acids were concentrated on the polar lipids rather than neutral lipids. The branched and odd chain fatty acid contents of mud‐feeding sea urchins were found to be relatively greater proportions of total fatty acids than in algae feeders.