bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive genomic analysis identifies MDM2 and AURKA as novel amplified genes in juvenile angiofibromas
Authors: Schick Bernhard , Wemmert Silke , Bechtel Ulrike , Nicolai Piero , Hofmann Thiemo , Golabek Wieslaw , Urbschat Steffi
Published: November 2006

Background.

Frequent β‐catenin mutations have been detected in juvenile angiofibromas, but the tumor pathogenesis remains unknown.

Methods.

Metaphase‐comparative genomic hybridization (CGH) was used to identify chromosomal aberrations in 29 tumor specimens. Two tumors were investigated using genome DNA microarrays.

Results.

Three hundred eleven chromosomal gains and losses were detected by metaphase‐CGH. Frequent chromosomal gains were detected at 4q, 6, 12, and X, while frequent chromosomal losses affected regions of chromosomes 8, 16, 17, 22, and Y. Genome DNA microarray analysis in 2 tumors of the series confirmed chromosomal aberrations, detected by metaphase‐CGH, and indicated genes such as AURKA (20q13.2) not being recognized by metaphase‐CGH.

Conclusion.

Metaphase‐CGH results confirmed numerous chromosomal aberrations in juvenile angiofibromas. The most frequent aberrations affected sex chromosomes. Further consensus regions of chromosomal aberrations were detected at 4q, 6, 8, 12, 16, 17, and 22. AURKA and MDM2 were identified as interesting novel amplified genes in juvenile angiofibromas. © 2006 Wiley Periodicals, Inc. Head Neck, 2007
Academic models and realworld problems
Authors: Brokatzky‐Geiger Jürgen
Published: November 2006

Commentary on “A Performance‐Based, Minimalist Human Resource Management Approach in Business Schools”
Flood hydrology of the Peace‐Athabasca Delta, northern Canada
Authors: Peters Daniel L. , Prowse Terry D. , Pietroniro Alain , Leconte Robert
Published: November 2006

This study conducted a systematic examination of the flood hydrology of the Peace‐Athabasca Delta (PAD), a complex and internationally important freshwater ecosystem located in northwestern Canada. Three distinct zones of floodwater origin within the PAD were discerned on the basis of the dominant hydrology and the topography represented by a digital‐elevation model (DEM): (1) perimeter Peace Delta, (2) perimeter Athabasca Delta, and (3) central delta lakes. Analysis of the satellite image and DEM‐derived flood maps of historically significant events, combined with field data of open‐water and ice‐influenced flood stages, revealed that ice‐jamming was the most effective and likely the only mechanism capable of recharging the highly elevated perimeter areas in the Athabasca and Peace Deltas. This supports the conclusion of previous studies that used hydrometric data external to the delta to infer inter‐delta flood conditions. By contrast, even the record open‐water flow to the Peace Delta could not generate overbank flow. Hydraulic simulation of the naturalized system (no dam & no weirs) suggests that overbanking of the lower Peace River would have been a rare occurrence without the effects of regulation. Both ice‐jam induced and open‐water high waters were found to recharge perched basins in the Athabasca Delta. Enlargement of the central delta lakes beyond the shoreline was determined to be an effective flood mechanism for filling low to mid‐elevation wetlands. Comparison of the observed and naturalized lake levels indicates that flow regulation of the Peace River and addition of the weirs on delta outflow channels has, depending on the year, led to an increase or a reduction in the annual maximum potential of inland flooding via lake expansion. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Generation of streamflow to seasonal high waters in a freshwater delta, northwestern Canada
Authors: Peters Daniel L. , Prowse Terry D.
Published: November 2006

Shallow lakes and wetlands in the Peace‐Athabasca Delta (PAD), one of the world's largest freshwater deltas located in northwestern Canada, are dependent on occasional flooding to replenish evaporated water. The hydrology of the PAD has experienced natural and human induced changes in recent times. Since the early 1970s, there has been a desire to restore water to perched wetlands by managing inundation of the perimeter deltas. Before such plans are implemented, it is important to understand the generation of annual peak ice‐induced and open‐water floodwaters to this Nordic delta. The hydroclimatology, physiography, size, and relative locations of sub‐basins exert a strong control on the runoff response. Ice‐jam floods in the lower Athabasca and Peace Rivers are generated by large snowmelt runoff from ‘trigger tributaries’ located in the downstream (foothills and plains) portions of the basin. Flood flows during the open‐water period are primarily generated by heavy rainfall runoff originating from the more elevated foothill/mountain regions where the precipitation process is enhanced by orography. In general, storage of alpine runoff in the headwaters of the Peace River places an increased dependence on downstream tributaries of the system to produce extreme flow events to the delta. Recommendations are made for additional hydrological modelling studies to assess the potential change to generation of extreme events from additional water retention/diversion schemes, land‐use change, and a changing hydroclimate within the upstream contributing basins of the PAD. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
A new approach to measuring the aerodynamic resistance to evaporation within a northern peatland using a modified Bellani plate atmometer
Authors: Kettridge Nicholas , Baird Andrew
Published: November 2006

This study considers evaporation from northern peatlands, which are important global stores of soil carbon. Evaporation is commonly simulated using the Penman–Monteith model. The model incorporates the aerodynamic resistance to vapour transfer (ra), which can currently only be measured using expensive, labour intensive micro‐meteorological methods. A new approach to measuring ra is presented. The approach involves accurately measuring the evaporation from a modified Bellani plate atmometer, of known surface resistance and temperature. With knowledge of basic meteorological parameters, ra can then be calculated. The approach is compared to modelled resistances within a northern peatland: no significant difference was found between modelled and measured ra. Copyright © 2006 John Wiley & Sons, Ltd.
Structure of a paramagnetic supermicroporous silica‐based material via a multinuclear solid‐state NMR monitoring
Authors: Bakhmutov Vladimir I. , Shpeizer Boris G. , Clearfield Abraham
Published: November 2006

The paramagnetic Si/Al material doped with 19.8% (weight) of Mn2+ has been characterized by the 1H, 13C, 27Al, 29Si MAS NMR spectra and the 1H, 29Si T1MAS relaxation measurements as a gel dried at 130 °C and as samples calcined at 504, 540 and 650 °C. It has been demonstrated that in spite of strong paramagnetic effects, NMR monitoring in combination with 29Si T1 relaxation experiments can be successful for structural descriptions of porous materials. Copyright © 2007 John Wiley & Sons, Ltd.
Maximum independent set for intervals by divide and conquer with pruning
Authors: Snoeyink Jack
Published: November 2006

Suppose a given set of n intervals contains a maximum independent set of k disjoint intervals. This brief note demonstrates that “divide and conquer with pruning” produces an easy, output‐sensitive O(n log k)‐time algorithm to compute such a maximum independent set. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(2), 158–159 2007
The stochastic time–cost tradeoff problem: A robust optimization approach
Authors: Cohen Izack , Golany Boaz , Shtub Avraham
Published: November 2006

We consider the problem of allocating resources to projects performed under given due dates and stochastic time–cost tradeoff settings. In particular, we show how to implement a state‐of‐the‐art methodology known as “robust optimization” to solve the problem. In contrast to conventional approaches, the model we develop results in management policies rather than optimal values for the original decision variables. Hence, the project manager can postpone decisions to the point of time when they are actually required and then make them according to the optimal policy (which employs cumulative data on the project progress). The solutions are guaranteed to be robust—that is, ensuring feasibility except when the uncertain parameters assume extreme values. Still, as we demonstrate through an extensive numerical example, the price we need to pay to obtain that robustness is relatively small even for high uncertainty levels. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(2), 175–188 2007
Gas‐phase kinetics of the reactions of O(3P) atoms with (Z)‐CHClCHCl, CCl2CH2, CCl2CCl2 and (E/Z)‐CFClCHCl at 298 K
Authors: Blanco María B. , Cometto Pablo M. , Taccone Raúl A. , Lane Silvia I. , Teruel Mariano A.
Published: November 2006

The kinetics of the gas‐phase reactions of O(3P) atoms with (Z)‐CHClCHCl, CCl2CH2, CCl2CCl2 and (E/Z)‐CFClCHCl were studied at 298 K using a discharge flow tube system. The overall rate constants based on the measured afterglow reactions were (2.0 ± 0.2) × 10−13, (11.3 ± 0.9) × 10−13, (1.9 ± 0.3) × 10−13, and (1.4 ± 0.3) × 10−14, respectively, all in units of cm3 molecule−1 sec−1. The experiments were carried out under pseudo‐first‐order conditions with [O(3P)]0 ≪ [chloroethene]. Halogen substitution in the alkenes is discussed in terms of reactivity with O(3P) and its relation to the ionization potential and the reactivity with OH radicals. Copyright © 2006 John Wiley & Sons, Ltd.
Rate constants for reaction of Cl atoms with hydrofluoroethers
Authors: Dalmasso Pablo R. , Nieto Jorge D. , Taccone Raúl A. , Teruel Mariano A. , Lane Silvia I.
Published: November 2006

The relative rate technique was used to measure the rate constants for the reactions of Cl atoms with CHF2OCH2CF3 and CHF2OCHFCF3. Experiments were carried out at 296 ± 2 K and atmospheric pressure using nitrogen as the bath gas. Using 1,1,1‐trichloroethane and 1,1,1,2‐tetrafluoroethane as the reference compounds, the following rate coefficients were derived: k(Cl + CHF2OCH2CF3) = (1.14 ± 0.27) × 10−14 and k(Cl + CHF2OCHFCF3) = (1.20 ± 0.12) × 10−15, in units of cm3 molecule−1 s−1. The rate constants obtained are compared with the literature data. The implications of the results with regard to the atmosphere are briefly considered. Copyright © 2006 John Wiley & Sons, Ltd.
Equivalent circuit analysis of the stability diagram of a few electron triple quantum dots
Authors: Gaudreau L. , Sachrajda A. S. , Studenikin S. , Zawadzki P. , Lapointe J. , Kam A.
Published: November 2006

Recent developments in single and double electrostatically confined quantum dots have shown that these devices are promising candidates for the implementation of quantum computation schemes in solid state systems. One of the obstacles for such an accomplishment is scalability. We present here the first realization of a triple lateral quantum dot with a few number of electrons, going down to fundamental configurations such as the vacuum state (no electrons in the system) or one electron in each quantum dot. New phenomena unseen in single or double dots are revealed involving charge and spin reconfigurations within the system, reminiscent of quantum cellular automata (QCA) functionalities. More importantly, it is necessary to understand these phenomena for they will be present in any three or more coupled quantum dots system. An equivalent circuit analysis of the system is used to reproduce these new features and to highlight some differences between experiments and the model, possibly arising from quantum phenomena not included in the circuit analysis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical modelling of electron transport in InAs/GaAs quantum dot superlattices
Authors: Vukmirović Nenad , Ikonić Zoran , Savić Ivana , Indjin Dragan , Harrison Paul
Published: November 2006

A theoretical model describing the electron transport in InAs/GaAs quantum dot infrared photodetectors, modelled as ideal quantum dot superlattices, is presented. The carrier wave functions and energy levels were evaluated using the strain dependent 8‐band k · p Hamiltonian and used to calculate all intra‐ and inter‐period transition rates due to interaction with phonons and electromagnetic radiation. The interaction with longitudinal acoustic phonons and electromagnetic radiation was treated perturbatively within the framework of Fermi's golden rule, while the interaction with longitudinal optical phonons was considered taking into account their strong coupling to electrons. The populations of energy levels were then found from a system of rate equations, and the electron current in the superlattice was subsequently extracted. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A hybrid model for the magneto‐optics of embedded nano‐objects
Authors: Wijers C. M. J. , Voskoboynikov O. , Liu J. L.
Published: November 2006

The influence of the surrounding semiconducting matrix upon the polarizability of embedded nano‐objects (nano‐rings) has been investigated using a hybrid discrete/continuum model. It describes embedded systems by excess discrete dipoles with excess polarizability against a uniform background with the host material dielectric constant. The polarizability combines the static polarizability of an ellipsoidal ring with a dynamic quantum mechanical frequency dependent term. The result of the model for the particular nano‐ring host combination investigated is an increased internal reflectance and an overall strong increment of the structure in reflectance/ellipsometric angles, displaying clearly the optical Aharonov‐Bohm effect. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
1.5 µm luminescence from InAs/GaxIn1–xNyAs1–y quantum dots grown on GaAs substrate
Authors: Richter M. , Hugues M. , Damilano B. , Massies J. , Duboz J.‐Y. , Reuter D. , Wieck A. D.
Published: November 2006

Self‐assembled InAs quantum dots encapsulated by Gax In1–x Ny As1–y (GINA) have been grown on GaAs (001) substrate by solid source molecular beam epitaxy. A wavelength of up to 1.52 µm is achieved for as‐grown samples with y = 1.7%. The growth temperature of the GINA cap layer and the ex‐situ annealing temperature are optimized in order to get the best photoluminescence characteristics. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time resolved measurements on low‐density single quantum dots at 1300 nm
Authors: Zinoni C. , Alloing B. , Monat C. , Li L. H. , Lunghi L. , Gerardino A. , Fiore A.
Published: November 2006

We present time integrated and time resolved measurements on single In/As quantum dots (QD) emitting at 1300 nm, at 10 K, embedded in a planar microcavity. We clearly identify a standard spectroscopic signature from single QDs and to compare the exciton line width and biexciton (BX) binding energy for several QDs. We present this data for QDs spatially selected by etched mesas and metallic apertures. Time resolved photoluminescence (PL) from single electron‐hole recombination in the ground state of the QD is investigated as a function of excitation power and temperature. The measurements reveal the presence of a background emission that delays the PL of excitons in the ground state. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of photoluminescence of CdSe/ZnSe quantum dots grown on GaAs and Si/Ge virtual substrates
Authors: Onishchenko Evgeny E. , Bagaev Victor S. , Kazakov Igor P. , Rzaev Murvetali M.
Published: November 2006

We have carried out temperature‐dependent studies of the photoluminescence properties of a set of CdSe/ZnSe quantum dot structures grown on conventionally used GaAs(100) substrates and Si(100)/Ge virtual substrates. Both single‐layer and multilayer QD structures have been studied. It was shown that the conventional MBE technique allows to grow CdSe/ZnSe QDs having the activation energy of luminescence quenching as large as 200 meV. Such issues as possible reasons of such a large activation energy and exciton migration in QD planes are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Valence band mixing in charged self‐assembled quantum dots
Authors: Léger Y. , Besombes L. , Maingault L. , Mariette H.
Published: November 2006

We analyze the optical emission of neutral, positively and negatively charged excitons in single II‐VI quantum dots presenting a high degree of linear polarization. This linear polarization is attributed to a valence band mixing and we show that in QDs combining both a shape anisotropy and an anisotropic in‐plane strain distribution, the linear polarization direction of the exciton are controlled by an interplay of the valence band mixing and e‐h exchange interaction. Similarly, under strong transverse magnetic field, the direction of the linearly polarized emission of the charged excitons are simultaneously controlled by the valence band mixing and the direction of the magnetic field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Origin of asymmetric splitting of a neutral exciton in a single semiconductor quantum dot
Authors: Suemune I. , Kumano H. , Kimura S. , Sasakura H. , Adachi S. , Muto S. , Song H. Z. , Hirose S. , Usui T.
Published: November 2006

It is well‐recognized that exciton‐state energy splitting makes it difficult to generate entangled photon pairs (EPP) from a single quantum dot (QD). It will be shown that the splitting of the exciton states originates from not only QD anisotropy but also ionization of residual impurities. This result shows that the growth of highly pure barrier layers will be necessary for the generation of EPP. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
InN quantum dots grown on GaN (0001) by molecular beam epitaxy
Authors: Dimakis E. , Georgakilas A. , Iliopoulos E. , Tsagaraki K. , Delimitis A. , Komninou Ph. , Kirmse H. , Neumann W. , Androulidaki M. , Pelekanos N. T.
Published: November 2006

The growth properties of InN quantum dots on GaN (0001) surfaces by molecular beam epitaxy are being investigated. The dependence of the dimensions and density of the dots on the nucleation temperature and their evolution during growth at a constant substrate temperature are described. It is shown that both dimensions and density can be accurately controlled through nucleation temperature and deposition time. In the range from 400 °C to 450 °C, the formation of InN quantum dot structures of small dimensions and high density is feasible. InN dots with less than 3nm height, less than 22 nm diameter and with density higher than 1.7×1011 cm–2 have been obtained. Finally, vertical alignment of dots was observed for a multi‐period InN quantum dot structure in GaN matrix, grown at 430 °C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inserting one single Mn ion into a quantum dot
Authors: Maingault L. , Besombes L. , Léger Y. , Mariette H. , Bougerol C.
Published: November 2006

Method of growth to get one single Mn ion in a Quantum Dot (QD) is presented. A simple analysis and a more realistic simulation prove that a low concentration of Mn is needed in order to have a maximum of QD with only one Mn. This is reached by using a ZnTe spacer after a Zn1–xMnxTe layer: Mn segregates in the ZnTe spacer and actually incorporates into the QDs. A study of photoluminescence spectra of samples with different spacer thicknesses validates this approach. A wavefunction modelisation and its application is also presented giving proofs of the importance of Mn position into the dot. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microscopic tight‐binding description for electronic and optical properties of InN/GaN quantum dots
Authors: Schulz S. , Baer N. , Schumacher S. , Gartner P. , Jahnke F. , Czycholl G.
Published: November 2006

The cover picture of this issue of physica status solidi (c) has been taken from the article [1].
Introducing reliability and load balancing in mobile IPv6‐based networks
Authors: Faizan Jahanzeb , EL‐Rewini Hesham , Khalil Mohamed
Published: November 2006

Mobile IPv6 is an enabling platform for creating IP mobility in the evolution path towards next generation service offerings. However, Mobile IPv6 does not provide reliability and load balancing in the network. In this paper, we introduce ‘Virtual HA Reliability Protocol.’ It is an extension to Mobile IPv6 that introduces reliability and load balancing in the Mobile IPv6‐based networks. It also provides solutions to the problems caused due to Home Agent failures in Mobile IPv6. These problems are: delayed failure detection, service interruption in the upper layer applications, increased workload on the Mobile Node, message overhead over the air interface, and IPsec Security Associations re‐establishment.

We also present the results of several experiments to assess the performance of our solution. The results show that our solution provides transparent Home Agent failure detection and recovery mechanisms. As a result, there is a significant reduction in message exchange over the air interface. Also, our solution provides high service availability in the upper layer applications. Moreover, there is reduced workload on the Mobile Node. Finally, the load balancing mechanism of our solution provides efficient, dynamic, and transparent load balancing among the multiple Home Agents. Thus our solution improves the overall Mobile IPv6 and upper layer applications performance. Copyright © 2006 John Wiley & Sons, Ltd.
Optimized bandwidth allocation with fairness and service differentiation in multimedia wireless networks
Authors: Nasser Nidal , Hassanein Hossam
Published: November 2006

In this article we present an optimal Markov Decision‐based Call Admission Control (MD‐CAC) policy for the multimedia services that characterize the next generation of wireless cellular networks. A Markov decision process (MDP) is used to represent the CAC policy. The MD‐CAC is formulated as a linear programming problem with the objectives of maximizing the system utilization while ensuring class differentiation and providing quantitative fairness guarantees among different classes of users. Through simulation, we show that the MD‐CAC policy potentially achieves the optimal decisions. Hence our proposed MD‐CAC policy satisfies its design goals in terms of call‐class‐differentiation, fairness and system utilization. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation and properties of an apoprotein derivative of human serum β‐lipoprotein
Authors: Gotto A. M. , Levy R. I. , Fredrickson D. S.
Published: November 2006

The aim of this study was to develop a convenient method for the preparation and study of a soluble delipidated form of human serum β‐lipoprotein. This was achieved by succinylation and delipidation with ether‐ethanol (3∶1). The succinylated apoprotein was soluble in either 0.13 M Tris‐HCl buffer, pH 8.2 (for β‐lipoprotein prepared by ultracentrifugation) or in the same Tris buffer to which 5 mM sodium decyl sulfate was added (for heparin‐Mn precipitated β‐lipoprotein). The immunological activity of β‐lipoprotein or its apoprotein were markedly altered by succinylation. Whereas the succinylated β‐lipoprotein appeared as one peak in the analytical ultracentrifuge, the succinylated apoprotein appeared as two. Under the electron microscope β‐lipoprotein and succinylated β‐lipoprotein were indistinguishable, appearing as uniform preparations of spherical particles 215 to 220 A in diamater.
Oxygenated fatty acids of oil from sunflower seeds after prolonged storage
Authors: Mikolajczak K. L. , Freidinger R. M. , Smith C. R. , Wolff I. A.
Published: November 2006

Abstracts

Chemical analysis of a number of sunflower (Helianthus annuus) seed oil samples revealed a low and variable percentage of hydrogen bromide‐reactive material. To characterize the compounds responsible for this reactivity, oil was extracted from selected introductions from Uruguay, Turkey, and Yugoslavia that had been subjected to prolonged storage. Two epoxy fatty acids and two conjugated dienolic acids were isolated from the methyl esters derived from these sunflower seed oils by using a combination of column chromatography and countercurrent distribution. The epoxy acids arecis‐9,10‐epoxystearic acid (0.5%) andcis‐9,10‐epoxy‐cis‐12‐octadecenoic (coronaric) acid (2.2%). Characterization of the dienols revealed that they are 9‐hydroxy‐trans‐10,cis‐12‐octadecadienoic acid (1.2%) and 13‐hydroxy‐cis‐9,trans‐11‐octadecadienoic acid (1.3%). Fresher seed of some of these introductions contained less of the oxygenated components.

Oil from recently produced seed of selected high‐oil Russian sunflower varieties, including some currently grown in the United States, contained no more than trace amounts of oxygenated acids. Though the relative contributions of genetic and environmental factors toward genesis of oxygenated acids are not established, increase of those acids in some sunflower lines as a result of storage has been demonstrated.
Constituents of the cotton bud: XII. The carotenoids in buds, seeds and other tissue
Authors: Thompson A. C. , Henson R. D. , Hedin P. A. , Minyard J. P.
Published: November 2006

Eleven carotenoid pigments were found in the bud, leaf, flower petal, seedling and seed of the cotton plant; nine were identified and quantitated. The most abundant carotenoids in the green tissue of the cotton plant were β‐carotene and lutein. Carotene hydrocarbons comprised 12% of the total carotenoids in the seed, 15% in the 1‐day‐old flower petal, 51% in the bud and 57% in green leaves. Only 5,8‐epoxy carotenoids were found in the flower petals and only 5,6‐epoxides in the other tissue but both were present in the seed. The colorless phytoene precursors to the carotenoids comprised from 20% to 38% of the total carotenoid pigment in the growing tissue of the plant.
Synthesis, purification and characterization of 7‐ketocholesterol and epimeric 7‐hydroxycholesterols
Authors: Chicoye E. , Powrie W. D. , Fennema O.
Published: November 2006

Various methods were assessed for the synthesis of 7‐ketocholesterol and epimeric 7‐hydroxycholesterols. Upon the oxidation of cholesteryl acetate with t‐butyl chromate, the resulting ketosterol acetate crystallized from methanol consisted of about 25% unoxidized cholesteryl acetate. After the sterol acetates were hydrolyzed in an aqueous K2CO3 medium, preparative TLC was used to fractionate the ketone from cholesterol.

Of all the reducing agents employed, only LiAlH4 reduced completely the purified 7‐ketocholesterol to 7‐hydroxycholesterols without side reaction products and ketone contamination. Yields of 21.3 mg of 7α‐hydroxycholesterol and 72.6 mg of 7β‐hydroxycholesterol were obtained by preparative TLC of a diol mixture prepared by the LiAlH4‐reduction of 100 mg of 7‐ketocholesterol. To accomplish the preparative TLC separation of diol bands without overlapping, a double development of a chromatoplate with ethyl ether‐cyclohexane (90∶10, v/v) and ethyl ether was essential.

Data on the melting point, optical rotation and infrared spectra, as well as TLC and GLC characteristics, were obtained for purified 7‐ketocholesterol and epimeric 7‐hydroxycholesterols.
The effect of antioxidant deficiency on tissue lipid composition in the rat. I. Gastrocnemius and quadriceps muscle
Authors: Witting L. A. , Horwitt M. K.
Published: November 2006

The gastrocnemius and quadriceps muscle phospholipids of the antioxidant‐deficient rat fed a source of both linoleate and linolenate showed a progressive net increase in arachidonate, a progressive net decrease in all other polyunsaturated fatty acids, and there was a concomitant accumulation of fluorescent pigment of the lipofuscin or ceroid type in the tissue. An increased incorporation of intraperitoneally injected, isotopically labeled acetate into not only arachidonate but also the other higher polyunsaturated fatty acids, was observed. The net loss of the higher polyunsaturated fatty acids from the membrane lipids (presumably via lipid peroxidation) apparently was partially compensated by a homeostatic mechanism which involved conversion of the available precursors, linoleate and linolenate, to the higher polyunsaturated fatty acids. The rates of decrease of the polyunsaturated fatty acids in the muscle phospholipids and accumulation of fluorescent pigment in the tissue were correlated with the rate of production of creatinuria.
cis‐5,cis‐9,cis‐12‐octadecatrienoic and some unusual oxygenated acids inXeranthemum annuum seed oil
Authors: Powell R. G. , Smith C. R. , Wolff I. A.
Published: November 2006

Seed oil ofXeranthemum annuum (family Compositae) contains a number of unusual fatty acids in addition to palmitic, stearic, oleic, linoleic and linolenic. These acids includecis‐5,cis‐9,cis‐12‐octadecatrienoic, 5%;cis‐9‐l,10‐l‐epoxyoctadecanoic, 3%;cis‐9‐l,10‐l‐epoxy‐cis‐12‐octadecenoic (coronaric), 8%; andcis‐12‐d,13‐d‐epoxy‐cis‐9‐octadecenoic (vernolic), 2%; as well as a mixture of two hydroxy acids, 11%. The absolute configurations of the two 9,10‐epoxy acids are established for the first time.
Distribution of free and conjugated sterols in orange and tangor juice sacs
Authors: Nagy Steven , Nordby Harold E.
Published: November 2006

Comparative studies of the sterol composition of four sterol fractions, vis., free sterols, sterol esters, sterol glucosides and esterified sterol glucosides, were conducted on the juice sacs of six varieties of oranges and two tangor varieties. The sterols quantified in each fraction were β‐sitosterol, campesterol, stigmasterol, cholesterol, 24‐ethylidene cholesterol, brassicasterol and 24‐methylene cholesterol. Each variety showed its own intrinsic composition for these sterols in the four sterol fractions.
Stimulation in vitro of galactocerebroside galactosidase by N‐decanoyl 2‐amino‐2‐methylpropanol
Authors: Arora R. C. , Radin N. S.
Published: November 2006

Amides resembling ceramide (fatty acyl sphingosine) were synthesized and tested in vitro for their effects on the rat brain β‐galactosidase which hydrolyzes galactosyl ceramide. The N‐decanoyl derivative of 2‐amino‐2‐methyl‐1‐propanol was most effective, giving a 34% stimulation at 0.15 mM concentration and a 60% stimulation at maximal levels. Addition of a hydroxyl group in the 3 position reduced the degree of stimulation, as did increasing or decreasing the length of the fatty acid portion. Omission of the branched methyl group resulted in inhibition instead of stimulation. Kinetic analysis indicates that the stimulator does not affect the binding of substrate to enzyme, but does speed the rate of hydrolytic action. Stimulation was also observed with the cerebrosidase in spleen and kidney. It is suggested that the stimulators act on an enzyme site other than the substrate‐active site.
Further evidence for the interconversion of monophosphoinositides in vivo
Authors: Holub B. J. , Kuksis A.
Published: November 2006

The incorporation of3H‐inositol into the molecular species of rat liver monophosphoinositides was studied as a function of time. At early time intervals following intraperitoneal injection of the tracer, the specific activity of the monoenoic and dienoic species exceeded that of the total and tetraenoic inoisitides by 7‐ and 14‐fold. From 90 min to 9 hr, the specific activity of the unfractionated phosphatide remained nearly constant while the pronounced decrease in activity [of the monoenoic and dienoic subfractions was concomitant with an increase in the radioactivity of the tetraenoic species, as found previously with32P‐ and14C‐glycerol. The present results suggest that the entire glycerophosphorylinositol backbone originally associated with the monoenoic and dienoic monophosphoinositides is converted into tetraenoic species with remarkable conservation of label in vivo.
The effect of sonication on lipase activity
Authors: Goodman L. P. , Dugan L. R.
Published: November 2006

Studies were made to evaluate the effect of sonication on activity of porcine pancreatic lipase and on activity of this lipase when in contact with substrate. Lipase was rapidly inactivated by sonication at 50 C, but was stable at 30 C or lower temperatures. Sonication for 4.5 min of lipase and olive oil at 38 C produced 2.7 times as much free fatty acid as without sonication. Hydrolysis of tripalmitin was achieved by sonication of lipase and tripalmitin dissolved in methyl myristate.
The absolute optical configurations of the isomeric 9,10‐epoxystearic, 9,10‐dihydroxystearic and 9,10,12‐trihydroxystearic acids
Authors: Morris L. J. , Crouchman M. L.
Published: November 2006

The absolute optical configuration of (−)‐cis‐9,10‐epoxystearic acid has been verified as being L. Here (−)‐erythro‐9,10‐dihydroxystearic acid, isolated from castor oil, was converted by stereospecific reactions to (+)‐cis‐9,10‐epoxystearic acid and was thereby proved to be D‐9,D‐10‐dihydroxystearic acid. Removal of the D‐12‐hydroxy group from the higher meltingerythro‐9,10,12‐trihydroxystearate derived from ricinoleic acid, after protection of the glycol group, gave the L‐9,L‐10‐dihydroxystearate derivative. This proved the high melting diastereoisomer to be L‐9,L‐10,D‐12‐trihydroxystearate and directly verified the supposition that the higher melting, arsenite‐complexing diastereoisomer of such oxidation pairs has thetrans‐10,12‐diol grouping. On this basis, the higher meltingthreo‐trihydroxystearate from ricinoleate must be D‐9,L‐10,D‐12‐trihydroxystearate and removal of the 12‐hydroxy group must give D‐9,L‐10‐dihydroxystearate which proved to be the levorotatory enantiomer. The dextrorotatory L‐9,D‐10‐dihydroxystearate was transformed by stereospecific reactions to (+)‐trans‐9,10‐epoxystearic acid, thereby defining the absolute configurations oftrans‐9,10‐epoxystearic acids. On the basis of these results conclusions may be drawn as to the stereospecificity and site of action of enzymes which hydrate 9,10‐epoxystearic acids.
The maturation of rat brain myelin
Authors: Eng Lawrence F. , Noble Ernest P.
Published: November 2006

Myelin fractions were prepared from brains of 9‐ to 90‐day‐old rats by continuous and discontinuous sucrose density gradient procedures. Total protein and lipid content of myelin showed little variation, but lipid composition changed significantly during maturation. Cholesterol, galactolipids, and ethanolamine glycerophosphatide plasmalogen increased whereas choline glycerophosphatide content decreased with increasing age. The changes in lipid composition were more marked in the myelin prepared by the discontinuous gradient technique. The significance of these lipid changes in relation to their organization in the myelin membrane is discussed.
Quantification of lowered cholesterol oxidation in guinea pigs with latent vitamin C deficiency
Authors: Ginter E. , Nemec R. , Červeň J. , Mikuš L.
Published: November 2006

Fifty‐two male guinea pigs fed on a scorbutigenic diet were divided into a control group (10 mg ascorbicacid per animal per day) and a group with latent vitamin C deficiency (2 weeks on the scorbutigenic diet only, followed by a maintaining dose of 0.5 mg ascorbic acid per animal per day). After 13 weeks, 26‐14C‐cholesterol was administered intraperitoneally to all the animals, in which the14C excretion in the expired CO2 and the urine and cholesterol specific activity in the blood serum and liver were then studied at intervals of 24 hr and 1, 3, 5, 7, 9 and 11 weeks. The ascorbic acid concentration in the liver and spleen of the control animals was five times higher than in vitain C‐deficient animals. The total cholesterol concentration in serum and liver was significantly higher in the vitamin C‐deficient guinea pigs. A two‐pool analysis of the disappearance curves of serum cholesterol specific activity showed that the size of the cholesterol pool A (blood and tissues with rapid cholesterol exchange) was greater in the vitamin C‐deficient animals. The rate of the transformation of cholesterol to bile acids was estimated as the ratio of14CO2 expired to liver cholesterol specific activity. Latent vitamin C deficiency caused significant slowing down of this process (controls: 11.8±0.6; vitamin C deficiency: 8.3±0.4 mg/24 r/500 g w/w). A significant correlation between the liver ascorbic acid concentration and the rate of cholesterol transformation to bile acids was found. The results demonstrate that ascorbic acid is necessary for a normal course of cholesterol catabolism. In latent vitamin C deficiency, the rate of cholesterol catabolism slows down and cholesterol consequently accumulates in the blood and liver of vitamin C‐deficient guinea pigs.
In vivo incorporation of3H arachidonic acid and14C linoleic acid into liver lipids from essential fatty acid‐deficient rats
Authors: Mercuri Osvaldo , Elena De Tomás Maria
Published: November 2006

Essential fatty acid (EFA)‐deficient rats were injected intraportally with a labeled solution containing3H arachidonic acid and14C‐linoleic acid during a 1 min period. Livers were quickly frozen, pulverized, and the lipids extracted and fractioned by thin layer chromatography. The incorporation of3H and14C into liver lipids was measured, and the per cent distribution of radioactivity into the different lipid fractions determined and compared with those previously obtained from normal rats. In contrast with normal rats, ca. 70% of the3H arachidonic acid and14C‐linoleic acid incorporated into total lipids from EFA‐deficient rats was recovered in the phospholipid fraction. From the results of this experiment, it is suggested that a more active deacylation‐reacylation cycle in EFA‐deficiency could be responsible for this increase.
Pentane from thermal decomposition of lipoxidase‐derived products
Authors: Evans C. D. , List G. R. , Dolev Ami , McConnell D. G. , Hoffmann R. L.
Published: November 2006

Thermal decomposition of 13‐hydroperoxyoctadeca‐9,11‐dienoic acid yields hydrocarbons as part of the scission products. Pentane is formed predominately and to the practical exclusion of all other short‐chain hydrocarbons.
Fatty acid composition of rat hearts as influenced by age and dietary fatty acids
Authors: Szuhaj B. F. , McCarl R. L.
Published: November 2006

Fatty acid composition of neutral and polar lipid fractions from rat hearts was determined in rats of different ages as their diet source changed. Piebald rats were weaned at 21 days and were fed standard lab chow. Lipids from rat hearts, mothers milk and lab chow were purified on a Sephadex G‐25 fine column and separated into neutral and polar lipid fractions by silicic acid column chromatography. These lipid fractions were then hydrolyzed and methylated with BF3 in methanol, prior to gas liquid chromatographic separation on a 1/8 in. × 10 ft aluminum column of 15% EGS on 80–100 mesh acid‐washed Chromosorb W. Three major fatty acids in the neutral lipid fraction comprised 72% of total neutral lipid fatty acids from young hearts. At sexual maturity (at least 74 days old) C18∶1 was the major fatty acid, followed by C16∶0 and C18∶0. The same three fatty acids comprised 83% of total polar lipid fatty acids, but C18∶0 was the major fatty acid, followed by C16∶0 and C18∶1. The fatty acid composition of dietary lipids influenced the total neutral lipid fatty acid composition of the rat heart, but had little influence on the fatty acid composition of the polar lipid fraction.
Monoethylenic isomers in cardiac lipids of rats fed partially hydrogenated herring oil
Authors: Conacher H. B. S. , Page B. D. , Beare‐Rogers J. L.
Published: November 2006

Compositional studies have been carried out to compare the monoethylenic fatty acid isomers of a partially hydrogenated herring oil with those found in the cardiac lipid of young rats fed this oil for 1 or 16 weeks. In general, all geometrical and positional isomers with chain lengths C16, C18, C20 and C22 found in the hydrogenated oil were also observed in cardiac lipid. Evidence was also obtained for the occurrence of β‐oxidation in the catabolism of thecis andtrans isomers of these long chain acids.
Hydrolysis of linoleate geometric isomers byGeotrichum candidum lipase
Authors: Jensen Robert G. , Gordon Dennis T. , Scholfield C. R.
Published: November 2006

Lipase (EC 3.1.1.3) from the microorganismGeotrichum candidum preferentially hydrolyzescis‐9 18∶1 andcis,cis‐9,12 18∶2 from triacylglycerols, largely ignoring all other positional isomers ofcis 18∶1 as well astrans‐9 18∶1. To obtain additional information about the specificity of the enzyme, two triacylglycerols were prepared and utilized as substrates. The lipase hydrolyzed 85%cis,cis‐9,12 18∶2 and 15%trans,trans‐9,12 18∶2 from the triacylglycerol, containing ca. 50% of each acid. From the triacylglycerol containing 46.3%cis,trans‐9,12 18∶2 and 53.7%trans,cis‐9,12 18∶2, 44.8 and 55.2% of the two acids were hydrolyzed. Therefore the enzyme discriminated against thetrans,trans isomer but not between thecis,trans andtrans,cis isomers.
Liver retinal reductase and oxidase activities in rats exposed to low environmental temperature
Authors: Sundaresan P. R. , Therriault Donald G.
Published: November 2006

The influence of low environmental temperature on retinal reductase and retinal oxidase activities in rat liver was examined after two and four weeks of cold exposure at 5 C. Liver retinal reductase decreased whereas retinal oxidase increased with time in control rats fed a retinol‐free diet, then replenished with retinyl acetate and maintained at 25 C. When rats under identical experimental conditions were exposed to 5 C, the decrease in retinal reductase and increase in retinal oxidase were both found to be greater at 5 C than at 25 C. These results support the hypothesis that increased metabolic rate from exposure of the animal to a cold environment increases the requirement for retinoic acid and decreases the storage of retinol. Even though changes in total liver retinol levels were similar in both groups, an increased utilization of retinol was indicated when the utilization of retinol was expressed as a ratio of total retinol removed from the liver to total weight gain of the animal.
Differences between the metabolism of linoleic and palmitic acid: Utilization for cholesterol synthesis and oxidation to respiratory CO2
Authors: Cenedella Richard J. , Allen Arthur
Published: November 2006

Measurements were made of the incorporation of intragastrically administered 1‐C14‐labeled linoleic and palmitic acid carbon into the total body cholesterol of the intact rat and of the rat's ability to oxidize these two labeled acids to respiratory CO2. As compared with palmitic acid, the intact rat and isolated rat tissues exhibit a greater ability to metabolize linoleic acid. This is evidenced by a greater utilization of linoleic acid carbon for synthesis of total body cholesterol and also by a preference for the oxidation of linoleic acid. The greater incorporation of linoleic acid carbon into cholesterol appears to reflect the preferential oxidation of linoleic acid by the liver, a main site of fatty acid oxidation and cholesterol biosynthesis. This preference of the rat to utilize linoleic acid carbon for the synthesis of cholesterol may help to explain the well documented observation that the plasma cholesterol of the rat increases as the linoleic acid content of the diet increases.
Effect of ethanol on plasma triglycerides in male and female rats
Authors: Hernell Olle , Johnson Owe
Published: November 2006

A single large dose of ethanol was given to fasted rats and to rats fed a fat‐free diet containing orotic acid. An increased plasma triglyceride concentration after ethanol feeding was consistently found in fasted male rats, while the results in fasted female rats varied between the experiments. The total rate of triglyceride secretion into the plasma in fasted rats was estimated as the Triton‐induced hypertriglyceridemia 6–7.5 hr after ethanol feeding. The effect of ethanol on the triglyceride secretion from extrahepatic sources was estimated in the same way in rats, with the hepatic triglyceride secretion blocked by orotic acid. Ethanol enhanced the Triton‐induced hypertriglyceridemia in both male and female fasted rats, but to a greater extent in male rats. Ethanol did not stimulate the extrahepatic triglyceride secretion during this period.
On methylating activity of L‐(methyl‐14C)‐methionine in metabolism of phospholipids by insectCeratitis capitata
Authors: Jimenez C. , Municio A. M. , Suarez A.
Published: November 2006

The methylating activity of L‐(methyl‐14C)‐methionine in different stages of development of the insectCeratitis capitata was studied in a series of in vitro and in vivo experiments. Larval and pharate adult homogenates of the insect were used in the in vitro conditions, and the utilization of the methyl group of methionine for the synthesis of different classes of phospholipids was evaluated. Incorporation of radioactivity in lipids by pharate adult homogenates was significantly higher than that by larval homogenates. In both cases, phosphatidyl ethanolamine showed the highest levels of radioactivity incorporation. Free bases from total lipid hydrolysates were resolved and identified by paper chromatography, and the labeling was investigated by radioactivity scanning of paper chromatograms. Significant differences were observed in the activity of both stages of development of the insect. Larval and pharate adult homogenates incorporated mainly the labeled methyl groups into ethanolamine. Monomethyl ethanolamine was the only methyl derivative that appeared in the hydrolysates of lipids synthesized by larval homogenates, whereas mono‐, di‐ and trimethyl ethanolamine clearly were detected in those synthesized by pharate adult homogenates. Administration of L‐(methyl‐14C)‐methionine to larvae confirmed the existence of methylation reactions in the metabolic activity of the insect.
Hydrocarbons from males, females, and larvae of pecan weevil:Curculio caryae (Horn)
Authors: Mody Naresh V. , Hedin Paul A. , Neel William W. , Miles D. Howard
Published: November 2006

As part of a program to identify as many as possible of the components of the pecan weevil,Curculio caryae (Horn), the hydrocarbons from males, females, and larvae were isolated by solvent extraction and column chromatography and subjected to gas liquid chromatographymass spectrometry analysis. n‐Alkanes from C14−C32 in the larvae and unsaturated and branched chain hydrocarbons from C20−C32 in males and females were found. There are no significant differences between the hydrocarbons of the male and female pecan weevils.