bluuebunny/crossref_metadata_2025 huggingface dataset:
THE OCCURRENCE OF FUSARIUM SPECIES IN CANADA: VI. TAXONOMY AND GEOGRAPHIC DISTRIBUTION OF FUSARIUM SPECIES ON PLANTS, INSECTS, AND FUNGI
Authors: Gordon W. L.
Published: January 2008

The present investigation was commenced in 1932 and has been continued annually since that time with the object of determining the identity, host range, and geographic distribution of the Fusarium species in Canada. Approximately 9000 isolates of Fusarium were studied. These isolates were obtained from 173 species and botanical varieties of plants, 14 species of insects, and 4 of fungi. Of the various species and botanical varieties of plants from which isolates were obtained, 19 were cereals and grasses, 19 were vegetable crops, 15 were fruit crops, 13 were field crops, 52 were ornamental plants, 31 were trees and shrubs, and 24 were common weed plants. Less than 1% of the total isolates was obtained from insects and fungi. Although most of the isolates originated in Manitoba, some were obtained from each of the other provinces of Canada except Newfoundland.A total of 18 species, 3 varieties, and 18 formae of Fusarium, classified in nine sections of the genus, were identified among the isolates from plants, insects, and fungi. These species, varieties, and formae are: F. chlamydosporum Wr. & Rg., F. poae (Pk.) Wr., F. sporotrichioides Sherb. (section Sporotrichiella); F. arthrosporioides Sherb., F. avenaceum (Fr.) Sacc. (Roseum); F. concolor Rg., F. semilectum Berk. & Rav. (Arthrosporiella); F. acuminatum (Ell. & Ev.) Wr., F. eauiseti (Cda.) Sacc. (Gibbosum); F. culmorum (W. G. Sm.) Sacc, F. graminearum Schwabe, F. heterosporum Nees emend. Raillo, F. sambucinum Fuckel, F. samb. var. coeruleum Wr., F. samb. f. 6 Wr. (Discolor); F. moniliforme Sheld., F. moniliforme var. subglutinans Wr. & Rg. (Liseola); F. lateritium Nees (Lateritium); F. oxysporum Schl. emend. S. & H., F. oxysporum var. redolens (Wr.) Gordon, F. oxysporum f. betae (Stewart) S. & H., f. callistephi (Beach) S. & H., f. cepae (Hanz.) S. & H., f. conglutinans (Wr.) S. & H., f. dianthi (Prill. & Del.) S. & H., f. fabae Yu & Fang, f. gladioli (Massey) S. & H., f. lilii Imle, f. lini (Bolley) S. & H., f. lycopersici (Sacc.) S. & H., f. melonis S. & H., f. narcissi S. & H., f. pini (Hartig) S. & H., f. tuberosi S. & H. (Elegans); F. solani (Mart.) App. & Wr. emend. S. & H., F. solani f. eumartii (Carp.) S. & H., f. phaseoli (Burk.) S. & H., f. pisi (Jones) S. & H., F. coeruleum (Lib.) Sacc. (Martiella).F. chlamydosporum, F. heterosporum, F. moniliforme var. subglutinans, as well as 14 formae of F. oxysporum and 3 formae of F. solani, are reported to occur in Canada for the first time in this series of papers.The six species isolated most commonly, as indicated by the number of hosts from which they were obtained, are F. oxysporum, F. acuminatum, F. solani, F. equiseti, F. avenaceum, and F. poae.The conidia and chlamydospores of F. chlamydosporum and F. heterosporum are illustrated by drawings.
STUDIES IN FOREST PATHOLOGY: XX. INVESTIGATIONS OF THE PATHOLOGICAL DETERIORATION IN KILLED BALSAM FIR
Authors: Basham J. T.
Published: January 2008

Studies were begun to assess the significance and interrelationships of five fungi consistently associated with the deterioration of balsam fir trees killed by the spruce budworm, and to explain the succession pattern of the fungi in that process. A yeast and Ophiostoma bicolor Davidson and Wells were the only fungi consistently isolated from the discolored cambium of dying or recently killed trees; Stereum chailletii Pers. and an unidentified hyphomycete, Fungus F, were the principal fungi isolated from the stained sapwood of trees dead less than one year; and Polyporus abietinus Dicks, ex Fries was the only fungus consistently associated with the rotted sapwood of trees dead for more than one year. A gradual and fairly regular lowering of the moisture content, pH, and strength of balsam fir sapwood from the healthy, living state through the various stages of deterioration was recorded. There was no evidence of marked inhibition or antagonism among the fungi tested in pure culture. Although the most vigorous growth of P. abietinus occurred in liquid media adjusted at pH 4.5, compared with 6.5 for Fungus F and S. chailletii, balsam fir sticks of about pH 6.0 were readily infected by P. abietinus in the laboratory. Sticks artificially infected with S. chailletii or P. abietinus developed a pronounced reddish stain and showed significant reductions in toughness, and the pH of aqueous extracts of these sticks was markedly reduced. The same properties of sticks infected with Fungus F differed very little from those of the check sticks. There was no evidence that either Fungus F or S. chailletii was inhibited by the presence of the other in balsam fir sapwood, or that the presence of either had any effect upon the deteriorating capacity of P. abietinus. It is suggested that the principal explanation for the succession pattern of fungi in the deterioration of balsam fir lies in a dependence upon changes in certain properties of the wood substrate, particularly in the moisture content of the sapwood.
The effect of selected pesticides on short-root development of greenhouse-grown Pinustaeda seedlings
Authors: South David B. , Kelley Walter D.
Published: February 2008

Tests with 4-month-old loblolly pine (Pinustaeda L.) seedlings grown in the greenhouse show decreased short-root formation when grown in soil treated with the root-inhibiting herbicides trifluralin and napropamide. However, short-root development of treated seedlings did not differ from controls after 7 months. Percentage of bifurcate roots of 7-month-old seedlings was increased by napropamide but they were not significantly affected by trifluralin. The herbicide bifenox did not affect short-root development of 4- or 7-month-old seedlings. Percentage of bifurcate roots was increased initially with bifenox but was not affected after 7 months. The systemic fungicide triadimefon decreased both short-root development and the percentage of bifurcate roots of 7-month-old seedlings.
Natural variation in merchantable stem biomass and volume among clones of Populustremuloides Michx.
Authors: Lehn Gordon A. , Higginbotham Kenneth O.
Published: February 2008

Stand density and biomass and volume of merchantable stems were determined and compared for six clones on each of two different sites in Alberta. One site (Blue Ridge) was typically boreal and the other (Nordegg) subalpine. Biomass and volume production at 5 years were significantly different among clones on a shared site and were also significantly different when individual trees were compared between sites. Stocking levels were significantly higher on the Nordegg site at 85 years but not high enough to prevent the Blue Ridge site from producing more biomass (six and a half times as much) and volume (four times as much) on an areal basis. Broad sense heritability estimates suggest that approximately one-third of the variation in biomass and volume of trees growing on each site was genetically based.
COMMUTATION RELATIONS AND SELF-CONSISTENCY IN ELECTRODYNAMICS FOR THE FIELDS IN TIME-VARYING MEDIA
Authors: CHOI JEONG RYEOL , OH JUN-YOUNG
Published: January 2008

In linear media with time-dependent parameters, various commutation relations for the field operators obtained from the Lewis–Riesenfeld invariant operator method are calculated. We investigated whether our development is self-consistent or not by evaluating the Heisenberg equation of motion for field operators using the associated commutation relation.
4-(OCTYLOXY)-N-(4-HEXYLPHENYL)-2-HYDROXYBENZALIMINE THERMOTROPIC COMPOUND: MORPHOLOGIC, MESOMORPHIC, THERMOTROPIC, THERMOOPTICAL AND THERMODYNAMICAL PROPERTIES
Authors: NESRULLAJEV ARIF , ERAN BELKIZ BILGIN , YÖRÜR ÇIDEM
Published: January 2008

In this work, the mesomorphic, morphologic, thermotropic, thermooptical, and thermodynamical properties of 4-(octyloxy)-N-(4-hexylphenyl)-2-hydroxybenzalimine thermotropic liquid crystalline compound, which was synthesized by our group, have been studied in detail. This compound displays smectic C and nematic mesophases. These mesophases are enantiotropic and exhibit specific confocal and schlieren textures, respectively.

Thermotropic, thermooptical, and thermodynamical properties of the compound at direct and reverse phase transitions between smectic C and nematic mesophases and also between nematic mesophase and isotropic liquid have been investigated. The peculiarities of the bistable heterophase regions of these phase transitions have been studied.
LINEAR RESPONSE THEORY FOR THE SPIN TRANSPORT
Authors: JIN PEI-QING , LI YOU-QUAN
Published: January 2008

We derive the “continuity-like” equation for the spin density in the system with SU (2) gauge potentials. Then we generalize the conventional Kubo formula for the spin transport, i.e., the linear response of the spin current to both the external U (1) and SU (2) fields. The nonconservation of the spin density is shown to play an essential role in keeping the consistency of the generalized Kubo formula between different gauges.
SPIN INTERFERENCE IN RASHBA 2DEG SYSTEMS
Authors: NITTA JUNSAKU
Published: January 2008

The gate controllable SOI provides useful information about spin interference.1 Spin interference effects are studied in two different interference loop structures. It is known that sample specific conductance fluctuations affect the conductance in the interference loop. By using array of many interference loops, we carefully pick up TRS Altshuler-Aronov-Spivak (AAS)-type oscillation which is not sample specific and depends on the spin phase. The experimentally obtained gate voltage dependence of AAS oscillations indicates that the spin precession angle can be controlled by the gate voltage.2 We demonstrate the time reversal Aharonov-Casher (AC) effect in small arrays of mesoscopic rings.3 By using an electrostatic gate we can control the spin precession angle rate and follow the AC phase over several interference periods. We also see the second harmonic of the AC interference, oscillating with half the period. The spin interference is still visible after more than 20π precession angle.

We have proposed a Stern-Gerlach type spin filter based on the Rashba SOI.4 A spatial gradient of effective magnetic field due to the nonuniform SOI separates spin up and down electrons. This spin filter works even without any external magnetic fields and ferromagnetic contacts. We show the semiconductor/ferromagnet hybrid structure is an effective way to detect magnetization process of submicron magnets. The problem of the spin injection from ferromagnetic contact into 2DEG is also disicussed.

Note from Publisher: This article contains the abstract only.
GENERATING and MANIPULATING SPINS IN SEMICONDUCTORS
Authors: AWSCHALOM DAVID D.
Published: January 2008

Spin-orbit coupling in semiconductors relates the spin of an electron to its momentum, and provides a pathway for electrically initializing and manipulating electron spins for applications in spintronics and spin-based quantum information processing. This coupling can be regulated with strain in bulk semiconductors and quantum confinement in semiconductor heterostructures. We will provide an overview of optical studies exploring spin dynamics in conventional and magnetic semiconductors, followed by recent experiments probing all-electrical generation and manipulation of spins. Using Faraday and Kerr rotation magneto-optical spectroscopies with temporal and spatial resolution, current-induced spin polarization1 and the spin Hall effect2 have been observed using both spatially-resolved and temporally-resolved techniques in bulk semiconductors. More recently, we have investigated the spin Hall effect and current-induced spin polarization in two-dimensional electron gases confined in (110) AlGaAs quantum wells using Kerr rotation microscopy.3 In marked contrast to previous measurements in three dimensional systems, the spin Hall profile in two dimensions shows a surprisingly complex structure and the current-induced spin polarization is out-of-plane. The experiments map the strong dependence of the current-induced spin polarization to the crystal axis along which the electric field is applied, reflecting the anisotropy of the spin-orbit interaction.

The effect of reducing feature sizes in electrical spintronic devices is relevant for future technological applications. To this end, we discuss related measurements probing electron spin dynamics in narrow two-dimensional InGaAs quantum well wires with widths ranging from the micron to the submicron scale.4 The data reveal a surprising slowing of the electron spin relaxation in reduced geometries.

These results reveal opportunities for tuning a spin source using quantum confinement, strain and device engineering in non-magnetic materials. This work was supported by the ARO, DARPA, NSF and ONR.

Note from Publisher: This article contains the abstract only.
MAGNETIC RACE-TRACK — A NOVEL STORAGE CLASS SPINTRONIC MEMORY
Authors: PARKIN STUART
Published: January 2008

A proposal for a novel storage-class memory is described in which magnetic domains are used to store information in a "magnetic race-track".1 The magnetic race-track shift register storage memory promises a solid state memory with storage capacities and cost rivaling that of magnetic disk drives but with much improved performance and reliability.

The magnetic race track is comprised of tall columns of magnetic material arranged perpendicularly to the surface of a silicon wafer. The domains are moved up and down the race-track by nanosecond long current pulses using the phenomenon of spin momentum transfer. The domain walls in the magnetic race-track are read using magnetic tunnel junction magnetoresistive sensing devices arranged in the silicon substrate. Recent progress in developing magnetic tunnel junction devices with giant tunneling magnetoresistance exceeding 350% at room temperature will be mentioned.2

Experiments exploring the current induced motion and depinning of domain walls in magnetic nano-wires with artificial pinning sites will be discussed. The domain wall structure, whether vortex or transverse, and the magnitude of the pinning potential is shown to have surprisingly little effect on the current driven dynamics of the domain wall motion.3 By contrast the motion of DWs under nanosecond long current pulses is surprisingly sensitive to their length.4 In particular, we find that the probability of dislodging a DW, confined to a pinning site in a permalloy nanowire, oscillates with the length of the current pulse, with a period of just a few nanoseconds. Using an analytical model and micromagnetic simulations we show that this behaviour is connected to a current induced oscillatory motion of the DW. The period is determined by the DW mass and the curvature of the confining potential. When the current is turned off during phases of the DW motion when the DW has enough momentum, there is a boomerang effect that can drive the DW out of the confining potential in the opposite direction to the flow of spin angular momentum.

Note from Publisher: This article contains the abstract only.
ANOMALOUS TRANSPORT IN METALS AND SEMICONDUCTORS
Authors: MACDONALD A. H.
Published: January 2008

According to the Kubo formula, the static uniform electric fields in a metal or semiconductor can induce coherence between band states far from the Fermi energy. This interband coherence response appears to be at odds with the normal view that transport is a Fermi-energy property, and is relatively unfamiliar since it makes a negligibly small contribution to the most commonly studied transport coefficients such as the longitudinal conductivity. It has recently been argued that interband coherence response can dominate the anomalous Hall conductivity of ferromagnetic metals and semiconductors and the spin-Hall conductivity of paramagnetic materials. I will review recent theoretical ideas related to the charge Hall conductivity of ferromagnetic materials and the spin Hall conductivity of paramagnetic materials and their relation to recent and future experiments.

Note from Publisher: This article contains the abstract only.
FOCUSING BEHAVIOR OF GAUSSIAN BEAM THROUGH A VARIABLE π-PHASE PLATE PLUS LENS WITH LONG FOCAL DEPTH
Authors: LIU JUAN , SUN XIAO-DONG , GU BEN-YUAN , WANG SHANG-QI , DI SI , HU BIN , LIU YUN
Published: January 2008

We investigate the optical properties of Gaussian beams diffracted by a variable π-phase plate clinging tightly to the lens with long focal depth and its dependence on the size of the π-phase plate and the preset long focal depth of the lens. The numerical results show that the π-phase plate with appropriate size plus the multifunctional lens illuminated by Gaussian beam can produce bi-focus along the propagation direction and a center hollow light, and the distance between two focal planes along the longitudinal direction and the transverse and longitudinal spot size of the hollow beam will vary when changing the size of the π-phase plate or the preset long focal depth. This investigation indicates that the distance between the focal planes and the spot sizes of the hollow light can be controlled by the appropriately chosen size of the π-phase plate and the preset long focal depth of the lens. Furthermore, we compare the optical characteristics produced by three existing phase functions of the lens with long focal depth. It is expected that this investigation will provide useful information in various optical tweezers for operating and controlling.
THE AMPLITUDE SQUEEZING EFFECTS OF THE ELECTROMAGNETIC FIELD IN SIX-WAVE INTERACTION MODEL
Authors: GIRI DILIP-KUMAR , GUPTA P. S.
Published: January 2008

The amplitude squeezing properties of the electromagnetic field is investigated in the fundamental, Stokes (probe) and signal mode in six-wave mixing process under short-time approximation based on a fully quantum mechanical approach. The interaction is looked upon as a process involving absorption of two pump photons and emission of three probe photons and one signal photon at different frequencies. The coupled Heisenberg quantum mechanical equations of motion involving real and imaginary parts of the quadrature operators are established and solved under short-time scale. The occurrence of amplitude squeezing effects in both the quadrature of the radiation field in the fundamental mode as well as in the Stokes (probe) mode is investigated using the required conditions of squeezing in each of the cases. It is also shown that the squeezing in the signal mode is found to be dependent on amplitude-squared squeezing of the initial pump field. This gives a method of converting higher-order (amplitude-squared) squeezing into normal squeezing.
DARK ENERGY, DARK MATTER AND GRAVITY
Authors: BERTOLAMI ORFEU
Published: January 2008

We discuss the motivation for high accuracy relativistic gravitational experiments in the solar system and complementary cosmological tests. We focus our attention on the issue of distinguishing a generic scalar theory of gravity as the underlying physical theory from the usual general-relativistic picture, where one expects the presence of fundamental scalar fields associated, for instance, with inflation, dark matter and dark energy.
TESTING STRONG MOND BEHAVIOR IN THE SOLAR SYSTEM
Authors: MAGUEIJO JOÃO , BEKENSTEIN JACOB
Published: January 2008

We summarize an interesting set of solar system predictions that we have recently derived for modified Newtonian dynamics (MOND). Specifically, we find that strong MOND behavior may become evident near the saddle points of the total gravitational potential. Whereas in Newtonian theory tidal stresses are finite at saddle points, they are expected to diverge in MOND, and to remain distinctly large inside a sizable oblate ellipsoid around the saddle point. While strong MOND behavior would be a spectacular "backyard" vindication of the theory, pinpointing the MOND bubbles in the setting of the realistic solar system may be difficult. Space missions such as the LISA Pathfinder, equipped with sensitive accelerometers, may be able to explore the larger perturbative region.
THE DEPARTMENT OF ENERGY HIGH ENERGY PHYSICS PROGRAM
Authors: TURNER KATHLEEN
Published: January 2008

This paper describes the high-energy-physics program at the US Department of Energy. The mission and goals of the program are described along with the breadth of the overall program. Information on recommendations from community-based panels and committees is provided. Finally, details about the main astrophysics and cosmology projects are given.
NETWORK FORMATION UNDER HETEROGENEOUS COSTS: THE MULTIPLE GROUP MODEL
Authors: KAMPHORST JURJEN , VAN DER LAAN GERARD
Published: January 2008

It is widely recognized that the shape of networks influences both individual and aggregate behavior. This raises the question which types of networks are likely to arise. In this paper we investigate a model of network formation, where players are divided into groups and the costs of a link between any pair of players are increasing in the distance between the groups that these players belong to. We give a full characterization of the networks induced by a minimal curb set for any number of groups. To do so, we show that in our multiple group model each minimal curb set is a so-called super-tight curb set, that is a minimal curb set satisfying the condition that in each state of the set every player has the same best reply. From the proof it follows that every recurrent class of an unperturbed best reply dynamics is a minimal (super-tight) curb set and reversely, which yields the characterization result. We show that in case of multiple groups networks in minimal curb sets may have features that can not occur in networks with at most two groups. Nevertheless, local centrality and center-sponsorship are still important characteristics of the networks in minimal curb sets.
ROBUST SOLUTION OF A TIME-VARIABLE INTERCEPTION PROBLEM: A CHEAP CONTROL APPROACH
Authors: TURETSKY VLADIMIR , GLIZER VALERY Y.
Published: January 2008

A planar interception problem of a maneuverable target is considered using the linearized kinematic model with variable velocities and first-order dynamics of the interceptor and target. The maneuverabilities of the interceptor and target are assumed to be variable. By using an auxiliary zero-sum linear-quadratic differential game with cheap controls of both players, an interception guidance law, linear with respect to the state vector, is derived. An analytical description of the set of initial positions (capture set) is obtained, from which this guidance law provides zero miss distance, subject to given maneuverabilities of the interceptor and target. A numerical example illustrating the analytical results is presented.
MOLECULAR DYNAMICS SIMULATION OF INTERACTIONS BETWEEN FUNCTIONALIZED CARBON NANOFIBERS AND POLYMER RESINS
Authors: GOU JIHUA , ANUMAKONDA KRISHNA , KHAN AURANGZEB
Published: January 2008

The discovery of carbon nanofibers has created a significant opportunity to develop high performance and cost-effective polymeric nanocomposites. However, significant challenges in the development of such nanocomposites lie in the poor dispersion of carbon nanofibers into polymer resins and the weak interfacial bonding between carbon nanofibers and polymer resins. These critical issues have to be addressed by chemical functionalization of carbon nanofibers. Understanding molecular interactions between functionalized carbon nanofibers and polymer resins is a crucial step towards their potential application in nanocomposites. In the present work, the effects of surface functional groups on molecular interactions between carbon nanofibers and polymer resins have been studied by using molecular dynamics simulations. It was found that chemical functionalization of vapor grown carbon nanofibers increased the amount of surface functional groups, which disturbed the original smooth graphitic planes of carbon nanofibers. The functionalization of carbon nanofibers decreased the amount of π-bonds on the surface of nanofibers, which resulted in a weaker inter-nanofiber interaction. The weaker inter-nanofiber interaction could contribute to better dispersion of carbon nanofibers within polymer resins. The simulation results provided fundamental information for the rational functionalization of carbon nanofibers to manipulate their nanoscale behaviors and properties in a predicative manner.
AXIAL TRANSPORT OF LOW DENSITY, SIMPLE FLUID IN NANOCHANNEL SYSTEMS WITH PARTIAL MOLECULAR WALL SLIP: MODELING AND SIMULATION
Authors: PAPPAS JONATHAN W. , NAUMAN E. BRUCE
Published: January 2008

A model for gas transport through nanochannels is presented. Molecular simulations of Argon (modeled as a Lennard–Jones fluid) flowing over a carbon surface were performed to develop a correlation for molecular wall slip based on temperature and angle of collision. The correlation is used to modify the oscillatory model of diffusion. Molecular transport is argued to be in one of two domains: near wall localized diffusion at low and moderate temperatures, and delocalized diffusion at high temperatures. The molecular diffusivity is found to exceed that predicted by Knudsen diffusion at high temperatures, and diffusive oscillatory models at all temperatures. Molecular simulations compare favorably with the presented model.
NANOPARTICLES AS A POSSIBLE MODERATOR FOR AN ULTRACOLD NEUTRON SOURCE
Authors: NESVIZHEVSKY V. V. , PIGNOL G. , PROTASOV K. V.
Published: January 2008

Ultracold and very cold neutrons (UCN and VCN) interact strongly with nanoparticles due to the similarity of their wavelengths and nanoparticles sizes. We analyze the hypothesis that this interaction can provide efficient cooling of neutrons by ultracold nanoparticles at certain experimental conditions, thus increasing the density of UCN by many orders of magnitude. The present analytical and numerical description of the problem is limited to the model of independent nanoparticles at zero temperature. Constraints of application of this model are discussed.
PHOTOLUMINESCENT ENHANCEMENT OF HgWO4 NANOFILMS USING TiO2 ADJUSTMENT
Authors: HE XIN-YAO , JIA RUNPING , OUYANG CHUN-FA , WANG XIA , YANG JUN-HE
Published: January 2008

As a new nanomaterial, HgWO 4 nanofilms are prepared by the self-inventive technique of collodion nanoparticles-dispersal and film-formation. Their photoluminescent properties are enhanced and then controlled through nano- TiO 2 doping. These approaches not only ensure film uniformity and fluorescence (FL) enhancement, but also realize a FL increase/decrease conversion effect. The relationships between HgWO 4 nanofilms' PL intensities and TiO 2 doped amounts are in good agreement with Gaussion function, and maximum PL intensities of HgWO 4 nanofilms are located at 3.8% ratio of TiO 2 nanoparticles.
"SURFACE-PROGRAMMED ASSEMBLY" OF NANOTUBE/NANOWIRE-BASED INTEGRATED DEVICES
Authors: HONG SEUNGHUN , KIM TAE HYUN , LEE JOOHYUNG , BYUN KYUNG-EUN , KOH JUNTAE , KIM TAEKYEONG , MYUNG SUNG
Published: January 2008

We present a review on recently-developed "surface-programmed assembly" strategy for massive production of nanotube/nanowire-based devices. In this process, surface molecular patterns guide the assembly and alignment of nanotubes/nanowires onto specific locations on solid substrates without relying on external forces. The assembled structures were further utilized to fabricate functional devices such as field effect transistors and sensors. Control experiments provided us rich scientific insights including "sliding kinetics" and "lens effect" during the assembly process. Since this method does not require high-temperature processing steps or unconventional fabrication facilities, it is readily available to conventional device industry and may open up new nanodevice industry based on carbon nanotubes and nanowires.
Cambrian orogeny in the Ribeira Belt (SE Brazil) and correlations within West Gondwana: ties that bind underwater
Authors: Schmitt R. S. , Trouw R. A. J. , Van Schmus W. R. , Passchier C. W.
Published: January 2008

A 530–490 Ma tectono-metamorphic event, the Búzios orogeny, is recognized within the Ribeira Belt, along the coast of SE Brazil. Tectonic evolution started with a Late Neoproterozoic marine basin and volcanic activity at
c
. 610 Ma. The rocks in this basin were affected by high-grade metamorphism at
c
. 530 Ma, coeval with deformational phases D
1
–D
2
, which generated compressive low-angle tectonic structures with top-to-NW tectonic transport. Large recumbent folds with NW–SE axes parallel to the main stretching lineation formed during D
3
as the Cabo Frio tectonic domain, the focus of this study, collided with the Oriental terrane to the NW. D
4
sub-vertical shear zones are limited in extent. A new U–Pb age of 501±6 Ma is reported for zircon from an amphibolite-facies shear zone related to either D
3
or D
4
. Post-tectonic 440 Ma pegmatites mark the final stage of tectono-magmatic activity. The Cabo Frio tectonic domain has African affinities and is exotic to the Ribeira Belt. Middle Cambrian deformational and metamorphic ages are also reported from the ‘Angolan’ Pan-African belt, the southern Kaoko and Damara belts in Namibia, and the Cuchilla Dionisio–Punta Del Este terrane in Uruguay. The occurrence of Cambrian metamorphic rocks along the present African and South American coastlines shows that Mesozoic rifting closely follows Palaeozoic sutures of West Gondwana.
Correlations between the classic Paraná and Cape–Karoo sequences of South America and southern Africa and their basin infills flanking the Gondwanides: du Toit revisited
Authors: Milani E. J. , De Wit M. J.
Published: January 2008

Early during the twentieth Century, pioneering correlations between the Palaeozoic–Mesozoic basins of South America and southern Africa were used by Alexander du Toit to support the initial concepts of continental drift and the proposal of a united Gondwana continent. New stratigraphic tools and data can now be used to further tease out similarities and differences to reconstruct the detailed histories of these, the Paraná and Cape–Karoo basins. In turn this knowledge can be used also to increase our understanding of the origin and evolution of Gondwana. Recent advances in tectonics and stratigraphy showed that both basins evolved together along a common early Palaeozoic Gondwana margin facing the Panthalassa. Thereafter, this margin was transformed into a series of linked foreland basins coupled to the evolution of the Gondwanides. In detail, the foreland successions differ considerably due to spatial and temporal differences in tectonic histories along the Gondwanides. Only towards the end of the Palaeozoic did both basins evolve and merge into a single continental-scale, and truly intracratonic, terrestrial Gondwana basin that persisted until the early Cretaceous. This shared history was once again disrupted in the Early Cretaceous during the opening of the South Atlantic Ocean.
Contemporaneous evolution of the Palaeoproterozoic–Mesoproterozoic sedimentary basins of the São Francisco–Congo Craton
Authors: Pedreira A. J. , de Waele B.
Published: January 2008

Deposition of Palaeo–Mesoproterozoic sedimentary rocks on the São Francisco–Congo craton started during Statherian taphrogenesis (1.8–1.75 Ga), as verified by ages of
c
. 1.7 Ga determined for volcanic rocks of the lower part of the Espinhaço Supergroup in the states of Minas Gerais and Bahia (Brazil). These basins contain volcanic rocks and conglomerates alternating with sandstones, argillites and dolomites, deposited in continental, transitional and marine environments. The rocks in the westernmost sector of the Congo Craton (Central Africa) compose the Chela Group, comprising sandstones, argillites and dolomites. In the easternmost region of the Congo Craton the Kibaran, Akanyaru, Kagera and Muva supergroups occur: the first three in the Kibaran Belt and the last in the Irumide Belt and on the Bangweulu Block. They consist predominantly of pelites and schists, sandstones and, in lesser proportion, conglomerates, deposited in shallow marine, fluvial and lacustrine environments. Their sedimentation ages are constrained through ages on felsic tuff layers as follows: Chela Group 1790±17 Ma, Kagera Supergroup 1780 ± 9 Ma, and Muva Supergroup 1879±13 Ma. These data show that broadly coeval and sedimentologically similar epi-continental sedimentary basins occurred on the São Francisco and Congo cratons, suggesting the possible existence of a long-lived wide epi-continental sea covering large areas of these cratons during Statherian times.
Comparisons between the northwestern Borborema Province, NE Brazil, and the southwestern Pharusian Dahomey Belt, SW Central Africa
Authors: dos Santos T. J. S. , Fetter A. H. , Neto J. A. N.
Published: January 2008

Geological and geochronological data for the northwestern part of the Brasiliano Borborema Province are described and compared with their counterparts in the Pan-African Dahomey (Pharusian) belt that flanks the southeastern margin of the West African Craton, where outcrops are sufficiently continuous to discern the nature of the collision during West Gondwana assembly. In the Médio Coreaú domain, NW Borborema Province, U–Pb and Sm–Nd data have revealed unusual basement rocks representing 2.35–2.30 Ga juvenile crust, along with large tracts of 2.15–2.10 Ga juvenile gneisses in the Ceará Central domain. These basement blocks were affected by two pulses of intracratonic extension at 1785 and 775 Ma. Prior to West Gondwana collision, a continental arc (the Santa Quitéria batholith) developed between 665 Ma and 620 Ma. The presence of this arc strengthens the hypothesis that convergence between the Borborema Province and the São Luis craton involved closure of an oceanic basin. New geochronological data are presented showing that Palaeoproterozoic orthogneisses (U–Pb upper intercept 2288±2 Ma) were affected by a major late Neoproterozoic event (554±4 Ma U–Pb lower intercept, 558±3 Ma Sm–Nd whole-rock and mineral isochron). Exhumation and cooling of granulite rocks between 568 and 550 Ma in the Médio Coreaú domain and between
c
. 587 and 576 in the West African Dahomey Belt indicate that the final tectonic phase was not simultaneous along this front of the orogen.
Intracellular ClC-3 chloride channels promote bone resorption in vitro through organelle acidification in mouse osteoclasts
Authors: Okamoto Fujio , Kajiya Hiroshi , Toh Kazuko , Uchida Shinichi , Yoshikawa Momono , Sasaki Sei , Kido Mizuho A. , Tanaka Teruo , Okabe Koji
Published: January 2008

ClC-7 Cl− channels expressed in osteoclasts are important for bone resorption since it has been shown that disruption of the ClCN7 gene in mice leads to severe osteopetrosis. We have previously reported that Cl− currents recorded from mouse osteoclasts resemble those of ClC-3 Cl− channels. The aim of the present study was to determine the expression of ClC-3 channels in mouse osteoclasts and their functional role during bone resorption. We detected transcripts for both ClC-7 and ClC-3 channels in mouse osteoclasts by RT-PCR. The expression of ClC-3 was confirmed by immunocytochemical staining. Mouse osteoclasts lacking ClC-3 Cl− channels (ClC-3−/− osteoclasts) derived from ClCN3 gene-deficient mice (ClC-3−/−) showed lower bone resorption activity compared with ClC-3+/+ osteoclasts derived from wild-type mice (ClC-3+/+). Treatment of ClC-3+/+ osteoclasts with small interfering RNA (siRNA) against ClC-3 also significantly reduced bone resorption activity. Electrophysiological properties of basal and hypotonicity-induced Cl− currents in ClC-3−/− osteoclasts did not differ significantly from those in ClC-3+/+ osteoclasts. Using immunocytochemistry, ClC-3 was colocalized with lysosome-associated membrane protein 2. Using pH-sensitive dyes, organelle acidification activity in ClC-3−/− osteoclasts was weaker than in ClC-3+/+ osteoclasts. Treatment of ClC-3+/+ osteoclasts with siRNA against ClC-3 also reduced the organelle acidification activity. In conclusion, ClC-3 Cl− channels are expressed in intracellular organelles of mouse osteoclasts and contribute to osteoclastic bone resorption in vitro through organelle acidification.
Inhibition of Src and p38 MAP kinases suppresses the change of claudin expression induced on dedifferentiation of primary cultured parotid acinar cells
Authors: Fujita-Yoshigaki Junko , Matsuki-Fukushima Miwako , Sugiya Hiroshi
Published: January 2008

Sjögren's syndrome and therapeutic radiation for head and neck cancers result in irreversible changes in the parenchyma of salivary glands, loss of acinar cells, prominence of duct cells, and fibrosis. To clarify mechanisms of salivary gland dysfunction, we identified a signaling pathway involved in the dedifferentiation of primary cultures of parotid acinar cells. We reported previously that the expression pattern of claudins changes during culture, is related to the three-dimensional organization of the cells, and reflects their ability to function as acinar cells. In this study, we found that this change of claudin expression is a process of dedifferentiation, because expression of other differentiation markers also changes during culture. The expression levels of claudins-4 and -6, cytokeratin 14, and vimentin are increased, and those of claudin-10, aquaporin 5, and amylase are decreased. Inhibitors of Src and p38 MAP kinases suppress these changes and increase the expression of acinar marker proteins. Differences in extracellular matrix components have no effect. Activation of p38 MAP kinase occurs during cell isolation from the parotid glands and is retained up to 6 h after the isolation. In contrast, activation of Src kinases does not increase during the cell isolation. The Src inhibitor PP1 suppresses the activation of p38 MAP kinase. Therefore, cellular stresses induced during cell isolation cause dedifferentiation and transition to duct-like cells through activation of p38 MAP kinase and constitutively active Src kinases.
Functional mitochondria are required for O2 but not CO2 sensing in immortalized adrenomedullary chromaffin cells
Authors: Buttigieg J. , Brown S. T. , Lowe M. , Zhang M. , Nurse C. A.
Published: January 2008

Catecholamine (CAT) release from adrenomedullary chromaffin cells (AMC) in response to stressors such as low O2 (hypoxia) and elevated CO2/H+ is critical during adaptation of the newborn to extrauterine life. Using a surrogate model based on a v -myc immortalized adrenal chromaffin cell line (i.e., MAH cells), combined with genetic perturbation of mitochondrial function, we tested the hypothesis that functional mitochondria are required for O2 sensing. Wild-type MAH cells responded to both hypoxia and increased CO2 (hypercapnia) with K+ current inhibition and membrane depolarization. Additionally, these stimuli caused a rise in cytosolic Ca2+ and CAT secretion, determined by fura-2 spectrofluorimetry and carbon fiber amperometry, respectively. In contrast, mitochondria-deficient (ρ0) MAH cells were hypoxia insensitive, although responses to hypercapnia and expression of several markers, including carbonic anhydrase II, remained intact. Rotenone (1 μM), a mitochondrial complex I blocker known to mimic and occlude the effects of hypoxia in primary AMC, was effective in wild-type but not ρ0 MAH cells. These data demonstrate that functional mitochondria are involved in hypoxia-sensing by adrenal chromaffin cells. We also show for the first time that, like their neonatal chromaffin cell counterparts, MAH cells are CO2 sensors; however, this property is independent of functional mitochondria.
Liver and muscle metabolic changes induced by dietary energy content and genetic selection in rainbow trout (Oncorhynchus mykiss)
Authors: Kolditz C. , Borthaire M. , Richard N. , Corraze G. , Panserat S. , Vachot C. , Lefèvre F. , Médale F.
Published: January 2008

We combined genetic selection and dietary treatment to produce a model to study metabolic pathways involved in genetic and nutritional control of fat deposition in fish muscle. Two experimental lines of rainbow trout, selected for a lean (L) or fat (F) muscle, were fed with diets containing either 10 or 23% lipids from the first feeding, up to 6 mo. At the end of the feeding trial, trout were distinguished by very different muscle fat content (from 4.2 to 10% wet weight), and line × diet interactions were observed for parameters related to fat storage. We analyzed the activity and gene expression of key enzymes involved in lipid metabolism (fatty acid synthase, hydroxyacyl-CoA dehydrogenase, carnitine palmitoyltransferase 1 isoforms, and peroxisome proliferator-activated receptor α) and glycolysis (hexokinase 1 and pyruvate kinase) as well as energy production (isocitrate dehydrogenase, citrate synthase, and cytochrome oxidase) in the liver and the white muscle of rainbow trout. The lipid-rich diet repressed the activity of the lipogenic enzymes and stimulated enzymes involved in fatty acid oxidation and glycolysis in liver but had little effect on muscle enzymes assessed in this study. Regarding the selection effect, enzyme activity and expression suggest that compared with the L line, the F line presented reduced hepatic fatty acid oxidation as well as reduced mitochondrial oxidative capacities and enhanced glucose utilization in both liver and muscle. Very few line × diet interactions were found, suggesting that the two factors (i.e., dietary energy content and selection) used in this study to modify muscle lipid content exerted some additive but mostly independent effects on these metabolic actors.
Regulation ofFto/Ftmgene expression in mice and humans
Authors: Stratigopoulos George , Padilla Stephanie L. , LeDuc Charles A. , Watson Elizabeth , Hattersley Andrew T. , McCarthy Mark I. , Zeltser Lori M. , Chung Wendy K. , Leibel Rudolph L.
Published: February 2008

Two recent, large whole-genome association studies (GWAS) in European populations have associated a ∼47-kb region that contains part of the FTO gene with high body mass index (BMI). The functions of FTO and adjacent FTM in human biology are not clear. We examined expression of these genes in organs of mice segregating for monogenic obesity mutations, exposed to underfeeding/overfeeding, and to 4°C. Fto/ Ftm expression was reduced in mesenteric adipose tissue of mice segregating for the Ay, Lepob, Leprdb, Cpefat, or tub mutations, and there was a similar trend in other tissues. These effects were not due to adiposity per se. Hypothalamic Fto and Ftm expression were decreased by fasting in lean and obese animals and by cold exposure in lean mice. The fact that responses of Fto and Ftm expression to these manipulations were almost indistinguishable suggested that the genes might be coregulated. The putative overlapping regulatory region contains at least two canonical CUTL1 binding sites. One of these nominal CUTL1 sites includes rs8050136, a SNP associated with high body mass. The A allele of rs8050136 associated with lower body mass than the C allele preferentially bound CUTL1 in human fibroblast DNA. 70% knockdown of CUTL1 expression in human fibroblasts decreased FTO and FTM expression by 90 and 65%, respectively. Animals and humans with various genetic interruptions of FTO or FTM have phenotypes reminiscent of aspects of the Bardet-Biedl obesity syndrome, a confirmed “ciliopathy.” FTM has recently been shown to be a ciliary basal body protein.
Intraportal administration of neuropeptide Y and hepatic glucose metabolism
Authors: Nishizawa Makoto , Shiota Masakazu , Moore Mary Courtney , Gustavson Stephanie M. , Neal Doss W. , Cherrington Alan D.
Published: January 2008

We examined whether intraportal delivery of neuropeptide Y (NPY) affects glucose metabolism in 42-h-fasted conscious dogs using arteriovenous difference methodology. The experimental period was divided into three subperiods (P1, P2, and P3). During all subperiods, the dogs received infusions of somatostatin, intraportal insulin (threefold basal), intraportal glucagon (basal), and peripheral intravenous glucose to increase the hepatic glucose load twofold basal. Following P1, in the NPY group ( n = 7), NPY was infused intraportally at 0.2 and 5.1 pmol·kg−1·min−1 during P2 and P3, respectively. The control group ( n = 7) received intraportal saline infusion without NPY. There were no significant changes in hepatic blood flow in NPY vs. control. The lower infusion rate of NPY (P2) did not enhance net hepatic glucose uptake. During P3, the increment in net hepatic glucose uptake (compared with P1) was 4 ± 1 and 10 ± 2 μmol·kg−1·min−1 in control and NPY, respectively ( P < 0.05). The increment in net hepatic fractional glucose extraction during P3 was 0.015 ± 0.005 and 0.039 ± 0.008 in control and NPY, respectively ( P < 0.05). Net hepatic carbon retention was enhanced in NPY vs. control (22 ± 2 vs. 14 ± 2 μmol·kg−1·min−1, P < 0.05). There were no significant differences between groups in the total glucose infusion rate. Thus, intraportal NPY stimulates net hepatic glucose uptake without significantly altering whole body glucose disposal in dogs.
Evidence That Xenon Does Not Produce Open Channel Blockade of the NMDA Receptor
Authors: Weigt Henry U. , Adolph Oliver , Georgieff Michael , Georgieff Eva M. , Föhr Karl J.
Published: January 2008

Previous studies had not excluded the possibility that the mechanism by which Xenon (Xe) blocks N-methyl-d-aspartate (NMDA) receptors might be that of an open-channel blocker. We tested this possibility on mutant NMDA receptors carrying an alanine (A) to cysteine (C) mutation located within the SYTANLAAF-motif of the third transmembrane region (TM3). This mutation was shown to yield constitutively open ion channels after modification with a thiol-modifying reagent. We expressed such mutant channels in Neuro2A cells and recorded glutamate (50 μM)-induced currents in the whole cell recording mode. Although Xe (3.5 mM) blocked the currents through the wild-type receptor NR1-1a/NR2A and NR1-1a/NR2B by ∼40% and those through the mutant receptors NR1-1a/NR2A(A650C) or NR1-1a/NR2B(A651C) by ∼30%, it was unable to block the currents through the methane thiosulfonate etyhlammonium-modified mutant receptors. On the other hand, established open-channel blockers of the NMDA receptor such as MK-801 (1 μM) or Mg ions (Mg2+; 1 mM) were able to block these permanently open channels. These results suggest that Xe does not act as a classical open-channel blocker at the NMDA receptor.
The Role of Prestin in the Generation of Electrically Evoked Otoacoustic Emissions in Mice
Authors: Drexl Markus , Mellado Lagarde Marcia M. , Zuo Jian , Lukashkin Andrei N. , Russell Ian J.
Published: January 2008

Electrically evoked otoacoustic emissions are sounds emitted from the inner ear when alternating current is injected into the cochlea. Their temporal structure consists of short- and long-delay components and they have been attributed to the motile responses of the sensory-motor outer hair cells of the cochlea. The nature of these motile responses is unresolved and may depend on either somatic motility, hair bundle motility, or both. The short-delay component persists after almost complete elimination of outer hair cells. Outer hair cells are thus not the sole generators of electrically evoked otoacoustic emissions. We used prestin knockout mice, in which the motor protein prestin is absent from the lateral walls of outer hair cells, and Tecta ΔENT/ΔENT mice, in which the tectorial membrane, a structure with which the hair bundles of outer hair cells normally interact, is vestigial and completely detached from the organ of Corti. The amplitudes and delay spectra of electrically evoked otoacoustic emissions from Tecta ΔENT/ΔENT and Tecta +/+ mice are very similar. In comparison with prestin +/+ mice, however, the short-delay component of the emission in prestin −/− mice is dramatically reduced and the long-delay component is completely absent. Emissions are completely suppressed in wild-type and Tecta ΔENT/ΔENT mice at low stimulus levels, when prestin-based motility is blocked by salicylate. We conclude that near threshold, the emissions are generated by prestin-based somatic motility.