bluuebunny/crossref_metadata_2025 huggingface dataset:
Habitat associations and conservation status of an endemic forest dwarf chameleon (Bradypodion sp.) from South Africa
Authors: Reisinger Walter J. , Stuart-Fox Devi M. , Erasmus Barend F.N.
Published: April 2006

We quantified habitat associations and evaluated the conservation status of a recently identified, undescribed species of dwarf chameleon, Bradypodion sp. nov. Dhlinza, endemic to scarp forest remnants in KwaZulu-Natal Province, South Africa. At the microhabitat scale the Dhlinza dwarf chameleon was found more often in forest gaps and near paths than highly disturbed edges or forest interior. Chameleon presence was not explained by forest physiognomic variables such as vine cover, shrub and tree density, or canopy cover. Presence near gaps may be better explained by the combined effects of the thermal microenvironment and food availability. The species is moderately common where it occurs, with estimated densities of 4.7, 8.7 and 29.7 individuals per ha within forest interior, edges and gaps respectively. At the landscape scale, the chameleon occurs only in three remnant forests: the Dhlinza, Entumeni and Ongoye Forests. The species' extent of occurrence was estimated to be 88 km2 and its area of occupancy 49 km2. Based on the small area of remaining suitable habitat, this species meets the requirements for categorization as Endangered according to IUCN Red List criteria.
Ambrosian processions to the baptisteries
Authors: BAILEY TERENCE
Published: April 2006

Idiosyncratic to the Milanese liturgy were the processions after Matins and Vespers to the two ancient baptisteries of St John the Baptist and St Stephen. These processions, held throughout the year except in Holy Week, were provided with a very large repertory of antiphons (psallendae). The observances are documented in the Ambrosian antiphoners, in the Manuale, and in the ordinal, but to answer some of the important questions left unanswered in these books has required a detailed analysis and comparison of evidence that is in certain respects contradictory.
Recent recordings of plainchant
Authors: WEBER JEROME F.
Published: April 2006

Last year (2005, no. 6), we greeted a recording that seemed to be directed in a special way to chant scholars. Two more discs of similar interest have arrived, the newest one an interpretation of the conflict, shall we call it, between Roman and Frankish cantors during the introduction of Roman chant into the Frankish kingdom (no. 1 in the list below). The chants were chosen for specific characteristics of Old Roman and Gallican style, but the stage is set by beginning with ‘Gregorius praesul’. Most of the selections have been recorded only rarely, and the Old Roman offertory ‘Deus enim firmavit’ (from Bodmer 74) with its verses is new to records. Benjamin Bagby accompanies himself on the lute in ‘A solis ortu’, the lament for Charlemagne, the choice of verses (neither version is complete) partly different from Alfred Deller's recording, 237 in my discography (1992, no. 19 on CD). The disc concludes with two familiar pieces, the Palm Sunday processional responsory ‘Collegerunt’ and the laudes regiae ‘Christus vincit’. The last (from Paris, BNF lat. 13159, a source not cited by Bukofzer in ‘The Music of the Laudes’) is the most imaginative performance on disc, the only one known to me that interjects the acclamations more fluidly than the familiar editions indicate.
Structure of the San Andreas fault zone at SAFOD from a seismic refraction survey
Authors: Hole J. A. , Ryberg T. , Fuis G. S. , Bleibinhaus F. , Sharma A. K.
Published: April 2006

Refraction traveltimes from a 46‐km long seismic survey across the San Andreas Fault were inverted to obtain two‐dimensional velocity structure of the upper crust near the SAFOD drilling project. The model contains strong vertical and lateral velocity variations from <2 km/s to ∼6 km/s. The Salinian terrane west of the San Andreas Fault has much higher velocity than the Franciscan terrane east of the fault. Salinian basement deepens from 0.8 km subsurface at SAFOD to ∼2.5 km subsurface 20 km to the southwest. A strong reflection and subtle velocity contrast suggest a steeply dipping fault separating the Franciscan terrane from the Great Valley Sequence. A low‐velocity wedge of Cenozoic sedimentary rocks lies immediately southwest of the San Andreas Fault. This body is bounded by a steep fault just northeast of SAFOD and approaches the depth of the shallowest earthquakes. Multiple active and inactive fault strands complicate structure near SAFOD.
Riverine influence on nitrogen fixation in the upwelling region off Vietnam, South China Sea
Authors: Voss Maren , Bombar Deniz , Loick Natalie , Dippner Joachim W.
Published: April 2006

Nitrogen fixation is assumed to be most important in oligotrophic subtropical regions of the oceans. Here we show that nitrogen fixation can also be pronounced in the upwelling region off Vietnam. We compare nitrogen fixation rates and other hydro‐chemical variables from the monsoon season with the intermonsoon season and find that nitrogen fixation rates are app. 10 times higher during the monsoon season. However, this was not the case in the actual upwelling region – a 40–50 km wide strip along the coast – but further offshore, where the Mekong plume was noticeable. Therefore, we hypothesize that the stability of the water column, micronutrients and/or trace metals in the Mekong river plume may be responsible for enhanced cyanobacterial growth. These cyanobacteria may be either Trichodesmium, unicellular, or diatom‐associated symbionts, the latter are known from other river plumes like the Amazon.
Composition of Titan's ionosphere
Authors: Cravens T. E. , Robertson I. P. , Waite J. H. , Yelle R. V. , Kasprzak W. T. , Keller C. N. , Ledvina S. A. , Niemann H. B. , Luhmann J. G. , McNutt R. L. , Ip W.‐H. , De La Haye V. , Mueller‐Wodarg I. , Wahlund J.‐E. , Anicich V. G. , Vuitton V.
Published: April 2006

We present Cassini Ion and Neutral Mass Spectrometer (INMS) measurements of ion densities on the nightside of Titan from April 16, 2005, and show that a substantial ionosphere exists on the nightside and that complex ion chemistry is operating there. The total ionospheric densities measured both by the INMS and the Cassini Radio and Plasma Wave (RPWS) experiments on Cassini suggest that precipitation from the magnetosphere into the atmosphere of electrons with energies ranging from 25 eV up to about 2 keV is taking place. The absence of ionospheric composition measurements has been a major obstacle to understanding the ionosphere. Seven “families” of ion species, separated in mass‐to‐charge ratio by 12 Daltons (i.e., the mass of carbon), were observed and establish the importance of hydrocarbon and nitrile chains in the upper atmosphere. Several of the ion species measured by the INMS were predicted by models (e.g., HCNH+ and C2H5+). But the INMS also saw high densities at mass numbers not predicted by models, including mass 18, which we suggest will be ammonium ions (NH4+) produced by reaction of other ion species with neutral ammonia.
Trees, networks, and hydrology
Authors: Rinaldo Andrea , Banavar Jayanth R. , Maritan Amos
Published: April 2006

This paper reviews theoretical and observational material on form and function of natural networks appeared in somewhat disparate contexts from physics to biology, whose study is related to hydrologic research. Moving from the exact result that drainage network configurations minimizing total energy dissipation are stationary solutions of the general equation describing landscape evolution, we discuss the properties and the dynamic origin of the scale‐invariant structure of river patterns and its relation to optimal selection. We argue that at least in the fluvial landscape, nature works through imperfect searches for dynamically accessible optimal configurations and that purely random or deterministic constructs are clearly unsuitable to properly describe natural network forms. We also show that optimal networks are spanning loopless configurations only under precise physical requirements that arise under the constraints imposed by continuity. In the case of rivers, every spanning tree proves a local minimum of total energy dissipation. This is stated in a theorem form applicable to generic networks, suggesting that other branching structures occurring in nature (e.g., scale‐free and looping) may possibly arise through optimality to different selective pressures. We thus conclude that one recurrent self‐organized mechanism for the dynamic origin of fractal forms is the robust strive for imperfect optimality that we see embedded in many natural patterns, chief and foremost hydrologic ones.
Blueprint for perturbative solution of flow and transport in strongly heterogeneous composite media using fractal and variational multiscale decomposition
Authors: Neuman Shlomo P.
Published: April 2006

This paper offers a blueprint for extending perturbative ensemble moment (and potentially other, e.g., Gaussian or perturbative Karhunen‐Loéve) solutions of stochastic flow and transport problems in composite, randomly heterogeneous porous media to cases in which medium heterogeneity is arbitrarily large. The proposed approach is based on a novel idea of combined fractal and variational multiscale decomposition. It considers log hydraulic conductivity to be a composite random field with piecewise statistically homogeneous increments characterized by a truncated power variogram, i.e., a truncated fractal. This consideration is supported either exactly or approximately by a growing amount of observational data. It allows decomposing the field into two or more mutually uncorrelated components having relatively small variances associated with a hierarchy of spatial correlation scales. Combining this fractal decomposition with a variational multiscale decomposition formalism, motivated by the multiscale nature of turbulence, allows decomposing flow and transport problems into two or more coupled sets of variational problems each of which is amenable to perturbative solution regardless of how heterogeneous the original field was. The problems are defined on a hierarchy of computational grids having discretization intervals proportional to the correlation scales. The proposed approach does not require introducing effective parameters on any scale; instead, it allows resolving flow and transport ensemble moments fully on multiple scales of spatial resolution. The approach nevertheless allows subgrid closure (another idea inspired by the literature on turbulence) through subgrid refinement or the use of effective subgrid parameters. It additionally offers the critically important capability of conditioning flow and transport analyses on multiscale measurements. Details are presented in the context of steady state single‐phase flow in a composite medium.
Effects of diffusive property heterogeneity on effective matrix diffusion coefficient for fractured rock
Authors: Zhang Yingqi , Liu Hui‐hai , Zhou Quanlin , Finsterle Stefan
Published: April 2006

Heterogeneities of diffusion properties are likely to influence the effective matrix diffusion coefficient determined from tracer breakthrough curves. The objectives of this study are (1) to examine if it is appropriate to use a single, effective matrix diffusion coefficient to predict breakthrough curves in a fractured formation, (2) to examine if a postulated scale dependence of the effective matrix diffusion coefficient is caused by heterogeneity in diffusion properties, and (3) to examine whether multirate diffusion results in the previously observed time dependence of the effective matrix diffusion coefficient. The results show that the use of a single effective matrix diffusion coefficient is appropriate only if the interchannel and intrachannel variability of diffusion properties is small. The scale dependence of the effective matrix diffusion coefficient is not caused by the studied types of heterogeneity. Finally, the multirate diffusion process does not result in the time dependence of the effective matrix diffusion coefficient.
3‐D convection studies on the thermal state in the lower mantle with post‐perovskite phase transition
Authors: Kameyama Masanori , Yuen David A.
Published: April 2006

The influences of the post‐perovskite (PPV) phase transition on the thermal state in the lower mantle are studied with a three‐dimensional model of mantle convection in a Cartesian domain under the extended Boussinesq approximation with variable viscosity and temperature‐dependent thermal conductivity. We have varied (i) the intensity of latent heat exchange associated with the PPV transition by increasing the density change and (ii) the temperature at the core‐mantle boundary (CMB) which determines the stability field of the PPV phase through the relative positioning with the phase transition temperature at the CMB. We found that the actual PPV transition hardly affects the thermal structure in the lower mantle, although it has a tendency to bend the vertical temperature profile toward the equilibrium thermodynamic conditions of the transition in extreme cases with enhanced latent heat exchange and CMB temperature lower than that of phase transition.
GW627368X ((N‐{2‐[4‐(4,9‐diethoxy‐1‐oxo‐1,3‐dihydro‐2H‐benzo[f]isoindol‐2‐yl)phenyl]acetyl} benzene sulphonamide): a novel, potent and selective prostanoid EP4 receptor antagonist
Authors: Wilson Richard J , Giblin Gerard M P , Roomans Susan , Rhodes Sharron A , Cartwright Kerri‐Ann , Shield Vanessa J , Brown Jason , Wise Alan , Chowdhury Jannatara , Pritchard Sara , Coote Jim , Noel Lloyd S , Kenakin Terry , Burns‐Kurtis Cynthia L , Morrison Valerie , Gray David W , Giles Heather
Published: April 2006

N‐{2‐[4‐(4,9‐diethoxy‐1‐oxo‐1,3‐dihydro‐2H‐benzo[f]isoindol‐2‐yl)phenyl]acetyl}benzene sulphonamide (GW627368X) is a novel, potent and selective competitive antagonist of prostanoid EP4 receptors with additional human TP receptor affinity.

At recombinant human prostanoid EP4 receptors expressed in HEK293 cells, GW627368X produced parallel rightward shifts of PGE2 concentration–effect (E/[A]) curves resulting in an affinity (pKb) estimate of 7.9±0.4 and a Schild slpoe not significantly different from unity. The affinity was independent of the agonist used.

In rings of phenylephrine precontracted piglet saphenous vein, GW627368X (30–300 nM) produced parallel rightward displacement of PGE2 E/[A] curves (pKb=9.2±0.2; slope=1).

GW627368X appears to bind to human prostanoid TP receptors but not the TP receptors of other species. In human washed platelets, GW627368X (10 μM) produced 100% inhibition of U‐46619 (EC100)‐induced aggregation (approximate pA2 ∼7.0). However, in rings of rabbit and piglet saphenous vein and of guinea‐pig aorta GW627368X (10 μM) did not displace U‐46619 E/[A] curves indicating an affinity of <5.0 for rabbit and guinea‐pig prostanoid TP receptors.

In functional assays GW627368X is devoid of both agonism and antagonist affinity for prostanoid CRTH2, EP2, EP3, IP and FP receptors. At prostanoid EP1 receptors, GW627368X was an antagonist with a pA2 of 6.0, and at prostanoid IP receptors the compound increased the maximum effect of iloprost by 55%. At rabbit prostanoid EP2 receptors the pA2 of GW627368X was <5.0.

In competition radioligand bioassays, GW627368X had affinity for human prostanoid EP4 and TP receptors (pKi=7.0±0.2 (n=10) and 6.8 (n=2), respectively). Affinity for all other human prostanoid receptors was <5.3.

GW627368X will be a valuable tool to explore the role of the prostanoid EP4 receptor in many physiological and pathological settings.

British Journal of Pharmacology (2006) 148, 326–339. doi:10.1038/sj.bjp.0706726
Dynamic scaling of the critical binary mixture methanol-hexane
Authors: Iwanowski I. , Sattarow A. , Behrends R. , Mirzaev S. Z. , Kaatze U.
Published: April 2006

Acoustical attenuation spectrometry, dynamic light scattering, shear viscosity, density, and heat capacity measurements of the methanol/n-hexane mixture of critical composition have been performed. The critical part in the sonic attenuation coefficients nicely fits to the empirical scaling function of the Bhattacharjee-Ferrell [Phys. Rev. A 24, 1643 (1981)] dynamic scaling model if the theoretically predicted scaled half-attenuation frequency Ω1∕2BF=2.1 is used. The relaxation rates of order parameter fluctuations, as resulting from the acoustical spectra, within the limits of experimental error agree with those from a combined evaluation of the light scattering and shear viscosity measurements. Both series of data display power law with amplitude Γ0=44×109s−1. The amplitude of the fluctuation correlation length follows as ξ0=0.33nm from the light scattering data and as ξ0=0.32nm from the amplitude of the singular part of the heat capacity if the two-scale factor universality relation is used. The adiabatic coupling constant g=0.11 results from the amplitude of the critical contribution to the acoustical spectrum near the critical point, in conformity with g=0.12 as following from the variation of the critical temperature with pressure along the critical line and the thermal expansion coefficient.
Some estimates of the surface tension of curved surfaces using density functional theory
Authors: Barrett Jonathan C.
Published: April 2006

Density functional theory is used to calculate the surface tension of planar and slightly curved surfaces, which can be written as γ(R)=γ∞(1−2δ∞∕R), where R is the radius of curvature of the surface. Calculations are performed for a Lennard-Jones fluid, split into a hard-sphere repulsive potential and an attractive part. The repulsive part is treated using the local density approximation. The attractive part is treated using a high temperature approximation (HTA) in which the pair correlation function is approximated by the Percus-Yevick pair correlation function of a uniform hard-sphere fluid evaluated at a position-dependent average density. An expression relating the Tolman length δ∞ to the density profile of the planar surface is derived. Numerical results are presented for the planar surface tension γ∞ and for δ∞ and are compared with those using mean field theory (MFT) and with those using the square-gradient approximation. Values for γ∞ using the HTA are 30%–40% higher than those using MFT. Values for δ∞ using the HTA are around −0.1 (in units of the Lennard-Jones parameter σ) and only weakly dependent on temperature. These values are less negative than the values from MFT. The square-gradient approximation gives reasonable estimates of the more accurate nonlocal results for both the MFT and the HTA.
The Cauchy problem for the wave equation in the Schwarzschild geometry
Authors: Kronthaler Johann
Published: April 2006

The Cauchy problem is considered for the scalar wave equation in the Schwarzschild geometry. We derive an integral spectral representation for the solution and prove pointwise decay in time.
Electron confinement in strongly coupled GaN∕AlN quantum wells
Authors: Tchernycheva M. , Nevou L. , Doyennette L. , Julien F. H. , Guillot F. , Monroy E. , Remmele T. , Albrecht M.
Published: April 2006

The electron confinement in double GaN∕AlN quantum wells coupled by an ultrathin AlN barrier has been investigated by means of structural and optical measurements. The intersubband absorption spectra present two peaks attributed to the e1-e2 and e1-e3 transitions, respectively. The results of photoluminescence and intersubband spectroscopies are compared with simulations of the electronic structure based on the envelope function formalism. A good agreement is obtained for all investigated samples. These results provide clear evidence that the potential drop at the GaN∕AlN heterointerfaces is not abrupt, but is spread over one monolayer.
Low-frequency voltage noise and electrical transport in [100]-tilt YBa2Cu3O7−x grain-boundary junctions
Authors: Liatti M. V. , Poppe U. , Divin Y. Y.
Published: April 2006

We have fabricated [100]-tilt YBa2Cu3O7−x grain-boundary junctions with high characteristic voltages IcRn and studied their low-frequency voltage noise. The intensities of normalized resistance and critical current fluctuations have been found to be equal in these junctions and a complete antiphase correlation between these two fluctuations has been demonstrated. These results show that quasiparticles and Cooper pairs in the [100]-tilt junctions tunnel directly through the same parts of the barrier. The band-bending model with charge fluctuations at the structural interface is indicated to be adequate for understanding current transport and voltage noise in high-Tc grain-boundary junctions.
Engineering of spin-lattice relaxation dynamics by digital growth of diluted magnetic semiconductor CdMnTe
Authors: Kneip M. K. , Yakovlev D. R. , Bayer M. , Karczewski G. , Wojtowicz T. , Kossut J.
Published: April 2006

The technological concept of “digital alloying” offered by molecular-beam epitaxy is demonstrated to be a very effective tool for tailoring static and dynamic magnetic properties of diluted magnetic semiconductors. Compared to common “disordered alloys” with the same Mn concentration, the spin-lattice relaxation dynamics of magnetic Mn ions has been accelerated by an order of magnitude in (Cd,Mn)Te digital alloys, without any noticeable change in the giant Zeeman spin splitting of excitonic states, i.e., without effect on the static magnetization. The strong sensitivity of the magnetization dynamics to clustering of the Mn ions opens a degree of freedom for spin engineering.
Experimental determination of microwave attenuation and electrical permittivity of double-walled carbon nanotubes
Authors: Dragoman M. , Grenier K. , Dubuc D. , Bary L. , Fourn E. , Plana R. , Flahaut E.
Published: April 2006

The attenuation and the electrical permittivity of the double-walled carbon nanotubes (DWCNTs) were determined in the frequency range of 1–65GHz. A micromachined coplanar waveguide transmission line supported on a Si membrane with a thickness of 1.4μm was filled with a mixture of DWCNTs. The propagation constants were then determined from the S parameter measurements. The DWCNTs mixture behaves like a dielectric in the range of 1–65GHz with moderate losses and an abrupt change of the effective permittivity that is very useful for gas sensor detection.
High-mobility electronic transport in ZnO thin films
Authors: Tsukazaki A. , Ohtomo A. , Kawasaki M.
Published: April 2006

A systematic study of electronic transport properties was carried out for ZnO thin films grown on high-temperature annealed buffer layers of semi-insulating Mg0.15Zn0.85O. As functions of growth temperature and oxygen pressure during laser molecular-beam epitaxy growth, there can be seen optimum growth conditions where gross concentration of intrinsic defects is thought to be reduced. For the best qualified film, Hall mobilities of 5000cm2V−1s−1 at 100K and 440cm2V−1s−1 at 300K were recorded with the residual electron densities of 4×1014 and 9×1015cm−3, respectively.
Temperature dependence of a silicon power device switching parameters
Authors: Habchi R. , Salame C. , Khoury A. , Mialhe P.
Published: April 2006

This study presents measurements of device switching parameters performed on a commercial power metal-oxide-semiconductor field-effect transistor under high-temperature conditions. Measured switching times show that the device response to being turned off becomes faster at high temperatures. The inverse drain-source current rapidly increases above the 300°C limit. I-V curves indicate that the saturation current in the channel increases with temperature.
Evidence for possible flexoelectricity in tobacco mosaic viruses used as nanotemplates
Authors: Kalinin Sergei V. , Jesse Stephen , Liu Weili , Balandin Alexander A.
Published: April 2006

Electromechanical coupling in individual tobacco mosaic viruses has been studied using piezoresponse force microscopy. Possible origins of the observed high resolution contrast, including the topographic crosstalk, difference in the elastic properties, and the intrinsic electromechanical coupling due to the piezoelectric and flexoelectric effects are discussed. Using simple estimates, we argue that, due in part to the small size and high symmetry of this particular material system, flexoelectric coupling can dominate the observed electromechanical behavior. The electrical manipulation of the virus particles, essential for nanoelectronic applications for which they are proposed, has also been demonstrated.
Enhanced optical near field from a bowtie aperture
Authors: Jin Eric X. , Xu Xianfan
Published: April 2006

The enhanced optical near field from a bowtie aperture in an aluminum film is experimentally demonstrated using near-field scanning optical microscopy. The full width half magnitude near-field optical spot is determined to be about 65×34nm2 by 458nm argon ion laser illumination, which is seven times smaller than those obtained from square and rectangular apertures of the same opening area. Light concentration and transmission enhancement of bowtie apertures promise a highly efficient nanoscale light source for near-field optical applications.
Combined normal and torsional mode in frequency-modulation atomic force microscopy for lateral dissipation measurement
Authors: Kunstmann T. , Schlarb A. , Fendrich M. , Paulkowski D. , Wagner Th. , Möller R.
Published: April 2006

We present a new method to measure lateral dissipation in frequency-modulation atomic force microscopy (FM-AFM). Conventional FM-AFM has been used to measure the topography. Additionally the cantilever has been excited in the first torsional mode, leading to a tip motion parallel to the surface. The dissipation of this motion is measured and reveals information that is different from the information provided by the dissipation of the tip motion normal to the surface.
Effect of ultraviolet light irradiation on macroscopic single-walled carbon nanotube bundles
Authors: Mikó Cs. , Milas M. , Seo J. W. , Gaál R. , Kulik A. , Forró L.
Published: April 2006

We have measured the electrical conductivity and the Young modulus of macroscopic oriented ropes containing single-walled carbon nanotubes under ultraviolet (UV) irradiation. We found that UV irradiation increases both the electrical conductivity and the strength of the macroscopic bundle. These phenomena are explained by the generation of cross-links between the tubes in the macroscopic bundle due to the UV-induced interaction between the solvent dimethyl-formamide and the free radicals present on the surface of carbon nanotubes. Transmission electron microscopy investigation shows that the wall structure of nanotubes is preserved during this process, which is a valuable advantage compared to electron irradiation.
Traitmill™: a functional genomics platform for the phenotypic analysis of cereals
Authors: Reuzeau Christophe , Frankard Valerie , Hatzfeld Yves , Sanz Anabel , Van Camp Wim , Lejeune Pierre , De Wilde Chris , Lievens Katrien , de Wolf Joris , Vranken Ernst , Peerbolte Rindert , Broekaert Willem
Published: April 2006

The improvement of quality and quantitative traits in industrial crops is among the most important goals in plant breeding. Many traits of interest are controlled by multiple genes and improvements have so far only been obtained through conventional breeding. The use of biotechnological tools to modify quantitative traits is highly challenging. CropDesign has developed TraitMill™, an automated plant evaluation platform allowing high-throughput testing of the effect of plant-based transgenes on agronomically valuable traits in crop plants. The focus of the platform is currently on rice, a good model for other important cereals such as maize and wheat. TraitMill™ offers a high-throughput prediction of gene function. Genes of validated function that confer trait improvement can then be transferred to other cereal crop species such as maize, but also to dicots, trees and ornamentals. TraitMill™ involves the following key components: (i) selection of candidate trait improvement genes among genes involved in signal transduction, cell cycle control, transcription, nutrient metabolism, etc.; (ii) a suite of validated constitutive or tissue-specific promoters from rice allowing for the selection of the most appropriate promoter–gene combination in view of the desired trait improvement; (iii) an industrialized plant transformation system generating tens of thousands of transgenic plants annually; and (iv) a robotized trait evaluation set-up for plant evaluation, proprietary image analysis software for measuring plant performance parameters and statistical analysis of results.
Methodology to establish a composite collection: case study in lentil
Authors: Furman Bonnie J
Published: April 2006

The International Center for Agricultural Research in the Dry Areas (ICARDA) is participating in a large-scale programme, Subprogram 1 of the Consultative Group on International Agricultural Research (CGIAR) Generation Challenge Program, that aims to explore the genetic diversity of the global germplasm collections held by the CGIAR research centres. This project will identify a ‘composite collection’ of germplasm for individual crops, representing the range of diversity of each crop species and its wild relatives, and characterize each composite set using anonymous molecular markers, mainly simple sequence repeats (SSRs). The overall goal of this project is to study diversity across given genera and identify genes for resistance to biotic and abiotic stresses that can be used in crop improvement programmes. ICARDA was responsible for creating the composite collection for lentil. ICARDA has the global mandate for lentil and houses the largest global collection of this crop with 10,509 accessions. From this collection, a global composite collection of 1000 lentil accessions was established with the aim to represent genetic diversity and the agro-climatological range of lentil. Accessions for the composite collection were compiled from landraces, wild relatives, and elite germplasm and cultivars. The methodology presented here combined classical hierarchical cluster analyses using agronomic traits and two-step cluster analyses using agro-climatological data linked to the geographical coordinates of the accessions' collection sites. Genotyping for 30 SSR loci will be carried out for all 1000 accessions. Plants grown for DNA analysis will be harvested and progeny will be evaluated under field conditions at ICARDA.
Efficient use of crop germplasm resources: identifying useful germplasm for crop improvement through core and mini-core collections and molecular marker approaches
Authors: Upadhyaya Hari D. , Gowda C.L.L. , Buhariwalla H.K. , Crouch J.H.
Published: April 2006

Conservation of crop germplasm diversity involves the establishment of in situ and ex situ genebanks. The major activities for ex situ genebanks include assembling, conserving, characterizing and providing easy access to germplasm for scientists. More than six million accessions are currently assembled in over 1300 genebanks worldwide. ICRISAT is one of the 15 CGIAR centres, with headquarters at Patancheru, India, and conserves genetic resources of sorghum, pearl millet, chickpea, pigeonpea, groundnut, and six small millets. The ICRISAT genebank holds 114,870 accessions from 130 countries, including both archival materials from various organizations throughout the world, and from fresh collections resulting from 213 missions in 62 countries. The ICRISAT genebank supplies annually over 40,000 germplasm samples to scientists worldwide. Sixty-six varieties selected from the basic germplasm have been released for cultivation in 44 countries, and ICRISAT has restored/repatriated crop germplasm to eight countries. The research focus is on germplasm diversity assessment, developing core and mini-core collections, and using a molecular characterization approach to both enhance the utilization of germplasm in research and improve the efficiency of germplasm management. Following these approaches, we have been able to identify a significant number of accessions with traits potentially relevant for crop improvement.
Towards improving the drought tolerance of rice in China
Authors: Liu Hongyan , Mei Hanwei , Yu Xinqiao , Zou Guihua , Liu Guolan , Luo Lijun
Published: April 2006

Drought tolerance (DT) is a very complex trait. For the purpose of developing DT rice cultivars, a research programme was initiated in 1997 in China, consisting of four coherent parts: the development of a DT field screen facility and evaluation standard; the collection, evaluation and enhancement of DT rice resources; DT gene/quantitative trait locus (QTL) discovery; and DT rice breeding. More than 2000 rice accessions, mostly from China, were collected and evaluated in a new DT screening facility with a powerful water management system. Eighty-six entries were selected to serve as a core DT collection. A set of 187 recombinant inbred lines was developed for the genetic mapping of DT and high yield-related QTL under drought conditions. Several DT rice cultivars adapted to southern and central China were released. DT rice CMS lines were developed and distributed to most parts of China to encourage the development of DT or water-saving hybrid rice.
Magnetic resonance imaging-guided diskography and diagnostic lumbar 0.23t MRI: an assessment study
Authors: Sequeiros Blanco R. , Niinimäki J. , Ojala R. , Haapea M. , Vaara T. , Klemola R. , Tervonen O.
Published: April 2006

Purpose: To describe the in vivo appearance of magnetic resonance imaging (MRI) diskograms of normal and degenerated lumbar intervertebral disks, and to evaluate the differences in imaging findings between sequential diagnostic MRI and MRI diskography.

Material and Methods: Nine consecutive patients underwent MRI-guided diskography in order to determine possible pain provocation during puncture and contrast medium injection. All patients had preceding clinical suspicion of lumbar diskogenic pain and findings of lumbar disk degeneration in diagnostic (MRI, computed tomography (CT), plain radiography). A 0.23T open MRI scanner with interventional tools was used for imaging and instrument guidance. On all patients, a complementary diagnostic MRI study of the lumbar spine before and after the MRI-guided disk injection was performed, and subsequent axial MRI diskograms were obtained.

Results: A total of 25 disk punctures were initialized, and 25 MRI diskograms were obtained and their expression described. There was a correlation between the degenerative disk findings visualized by diagnostic MRI and MRI diskograms.

Conclusion: The use of gadolinium contrast media in MRI-guided diskography enables the evaluation of MRI diskograms. Our results suggest that MRI-guided diskography can be used to substitute conventional diskography or CT-diskography and as an augmenting method to assess diagnostic information upon degenerative processes of the lumbar spine.
Availability, indications, and technical performance of computed tomographic colonography: a national survey
Authors: Fisichella V. , Hellström M.
Published: April 2006

Purpose: To determine the availability, indications, and technique of computed tomographic colonography (CTC) in Sweden and to investigate opinions on its future role in colon imaging.

Material and Methods: In May 2004, a questionnaire on CTC was mailed to all Departments of Radiology in Sweden, and one year later a telephone interview was conducted with the departments that intended to start a CTC service.

Results: Ninety-nine departments (83%) answered the questionnaire, indicating that 23/99 (23.2%) offered a CTC service. Reasons for non-implementation of CTC were lack of CTC training in 34/73 (46.6%) and non-availability of multi-detector row CT scanners in 33/73 (45.2%), while 26% were awaiting further scientific documentation on CTC. Incomplete colonoscopy was the main indication for CTC in 21/23 (91.3%) departments performing CTC. Dual positioning, room air insufflation, and thin-slice collimation were used in all the responding departments. The number of CTC studies performed varied from 1–5 (26.1%) to more than 200 (17.4%). Intravenous contrast material was routinely administered by 9/23 (39.1%) departments. Out of 30 (39.5%) departments that in 2004 intended to start CTC, 9 (30%) had done so by June 2005. A total of 32/99 (32.3%) departments had therefore started CTC by June 2005. Half of the departments that replied believed that CTC would absolutely or probably replace barium enema in the future.

Conclusion: The survey shows relatively limited diffusion of CTC practice in Sweden, with approximately one-third of radiology departments offering a CTC service, mostly on a small scale. A wider dissemination of CTC requires further scientific documentation of its capability, intensified educational efforts, and additional funding.
Multi-slice computed tomography appearance of abscess of cavum septum pellucidum: a case report and review of the literature
Authors: Vasudev M. K. , Chavan R. G. , Nagarajan K. , Shukla D. , Devi B. I.
Published: April 2006

Abscesses involving the cavum septum pellucidum are rare and, owing to their location, detection may be difficult with routine conventional computed tomography (CT). Only a few isolated cases have been reported and mostly in children. We report a case of abscess involving the cavum septum pellucidum in an adult and its appearance on multi-slice spiral CT.
Macrophage uptake of ultra-small iron oxide particles for magnetic resonance imaging in experimental acute cardiac transplant rejection
Authors: Penno E. , Johnsson C. , Johansson L. , Ahlström H.
Published: April 2006

Purpose: To discriminate between acutely rejecting and non-rejecting transplanted hearts using a blood pool contrast agent and T2* magnetic resonance imaging (MRI) in a clinical 1.5T scanner.

Material and Methods: Allogeneic and syngeneic heterotopic heart transplantations were performed in rats. One allogeneic and one syngeneic group each received either the ultra-small iron oxide particle (USPIO), at two different doses, or no contrast agent at all. MRI was performed on postoperative day 6. Immediately after the MR scanning, contrast agent was injected and a further MRI was done 24 h later. Change in T2* was calculated.

Results: No significant difference in change in T2* could be seen between rejecting and non-rejecting grafts in either of the doses, or in the control groups. There was a difference between the allogeneic group that received the higher contrast agent dose and the allogeneic group that did not receive any contrast agent at all.

Conclusion: In our rat model, measurements of T2* after myocardial macrophage uptake of AMI-227 in a clinical 1.5T scanner were not useful for the diagnosis of acute rejection.
Treatment of recurrent chordomas by percutaneous ethanol injection therapy and radiation therapy
Authors: Nakajo M. , Ohkubo K. , Fukukura Y. , Nandate T. , Nakajo M.
Published: April 2006

We report a case of recurrent sacral chordomas that have been successfully controlled by the combination therapy of percutaneous ethanol injection therapy (PEIT) and radiation therapy in a 71-year-old man. PEIT may be one of the adjuvant therapies for recurrent chordomas.
Postprocedural monitoring of cerebral aneurysms
Authors: Kähärä V.
Published: April 2006

The treatment of intracranial aneurysms has been revolutionized since the introduction of electrolytically detachable platinum coils in 1991. Since this basic innovation, many refinements of the embolic materials and techniques have emerged. Today, in Europe, half of all aneurysms are treated endoarterially and this share is growing. The reassuring results of the International Subarachnoid Aneurysm Trial (ISAT) have changed the treatment strategy from neurosurgical clipping to embolization. However, the role of these alternative modes of treatment varies between institutions and countries. An angiographic follow-up pattern after endovascular treatment has remained largely undefined and in the same way there has been much diversity in applying alternative imaging modalities. Although some institutions continue to perform intervalled digital subtraction angiography, magnetic resonance angiography has assumed an increasing role. A vast majority of patients with embolized aneurysms are eligible to be monitored solely by non-contrast three-dimensional time-of-flight technique.
Book Reviews
Authors: Wolff P. Aa.
Published: April 2006

M. D. Anderson Cancer Care Series: Gastrointestinal Cancer. Edited by Jaffer A. Ajani, Steven A. Curley, Nora A. Janjan and Patrick M. Lynch. Series editors: Aman U. Buzdar and Ralph S. Freedman. Springer Verlag, Springer Science + Business Media inc (USA), 2005. ISBN 0-387-22090-9. Paperback. 394 pages. Price €85.55.
Formation of a WIP-, WASp-, actin-, and myosin IIA–containing multiprotein complex in activated NK cells and its alteration by KIR inhibitory signaling
Authors: Krzewski Konrad , Chen Xi , Orange Jordan S. , Strominger Jack L.
Published: April 2006

The tumor natural killer (NK) cell line YTS was used to examine the cytoskeletal rearrangements required for cytolysis. A multiprotein complex weighing ∼1.3 mD and consisting of WASp-interacting protein (WIP), Wiskott-Aldrich syndrome protein (WASp), actin, and myosin IIA that formed during NK cell activation was identified. After induction of an inhibitory signal, the recruitment of actin and myosin IIA to a constitutive WIP–WASp complex was greatly decreased. Both actin and myosin IIA were recruited to WIP in the absence of WASp. This recruitment correlated with increased WIP phosphorylation, which was mediated by PKCθ. Furthermore, the disruption of WIP expression by WIP RNA interference prevented the formation of this protein complex and led to almost complete inhibition of cytotoxic activity. Thus, the multiprotein complex is important for NK cell function, killer cell immunoglobulin-like receptor inhibitory signaling affects proteins involved in cytoskeletal rearrangements, and WIP plays a central role in the formation of the complex and in the regulation of NK cell activity.
Lamina-associated polypeptide 2α regulates cell cycle progression and differentiation via the retinoblastoma–E2F pathway
Authors: Dorner Daniela , Vlcek Sylvia , Foeger Nicole , Gajewski Andreas , Makolm Christian , Gotzmann Josef , Hutchison Christopher J. , Foisner Roland
Published: April 2006

Lamina-associated polypeptide (LAP) 2α is a nonmembrane-bound LAP2 isoform that forms complexes with nucleoplasmic A-type lamins. In this study, we show that the overexpression of LAP2α in fibroblasts reduced proliferation and delayed entry into the cell cycle from a G0 arrest. In contrast, stable down-regulation of LAP2α by RNA interference accelerated proliferation and interfered with cell cycle exit upon serum starvation. The LAP2α-linked cell cycle phenotype is mediated by the retinoblastoma (Rb) protein because the LAP2α COOH terminus directly bound Rb, and overexpressed LAP2α inhibited E2F/Rb-dependent reporter gene activity in G1 phase in an Rb-dependent manner. Furthermore, LAP2α associated with promoter sequences in endogenous E2F/Rb-dependent target genes in vivo and negatively affected their expression. In addition, the expression of LAP2α in proliferating preadipocytes caused the accumulation of hypophosphorylated Rb, which is reminiscent of noncycling cells, and initiated partial differentiation into adipocytes. The effects of LAP2α on cell cycle progression and differentiation may be highly relevant for the cell- and tissue-specific phenotypes observed in laminopathic diseases.
Co-Carriage Rates of Vancomycin-ResistantEnterococcusand Extended-Spectrum Beta-Lactamase-Producing Bacteria Among a Cohort of Intensive Care Unit Patients: Implications for an Active Surveillance Program
Authors: Harris Anthony D. , Nemoy Lucia , Johnson Judith A. , Martin-Carnahan Amy , Smith David L. , Standiford Hal , Perencevich Eli N.
Published: April 2006

Objective:

To assess the co-colonization rates of extended-spectrum beta-lactamase (ESBL)-producing bacteria and vancomycin-resistantEnterococcus(VRE) obtained on active surveillance cultures.

Design:

Prospective cohort study.

Setting:

Medical and surgical intensive care units (ICUs) of a tertiary-care hospital.

Patients:

Patients admitted between September 2001 and November 2002 to the medical and surgical ICUs at the University of Maryland Medical System had active surveillance perirectal cultures performed. Samples were concurrently processed for VRE and ESBL-producing bacteria.

Results:

Of 1,362 patients who had active surveillance cultures on admission, 136 (10%) were colonized with VRE. Among these, 15 (positive predictive value, 11%) were co-colonized with ESBL. Among the 1,226 who were VRE negative, 1,209 were also ESBL negative (negative predictive value, 99%). Among the 1,362 who had active surveillance cultures on admission, 32 (2%) were colonized with ESBL. Among these, 15 (47%) were co-colonized with VRE. Of the 32 patients colonized with ESBL, 10 (31%) had positive clinical cultures for ESBL on the same hospital admission. For these 10 patients, the surveillance cultures were positive an average of 2.7 days earlier than the clinical cultures.

Conclusions:

Patients who are colonized with VRE can also be co-colonized with other antibiotic-resistant bacteria such as ESBL-producing bacteria. Our study is the first to measure co-colonization rates of VRE and ESBL-producing bacteria. Isolating VRE-colonized patients would isolate 47% of the ESBL-colonized patients without the need for further testing. Hence, active surveillance for VRE should also theoretically diminish the amount of patient-to-patient transmission of ESBL-producing bacteria.
Use of a Novel Selective Medium to Detect Methicillin-ResistantStaphylococcus aureusin Colonized Patients of an Intensive Care Unit
Authors: Dias Cícero Gomes , Röpke Marcos Vinícius Rosa , Superti Silvana , Berquó Laura , d'Azevedo Pedro
Published: April 2006

Background:

Detection of colonized patients is important for implementing control measures for methicillin-resistantStaphylococcus aureus(MRSA). Laboratory detection of MRSA carriers is increased by the use of selective screening media, helping control dissemination of such organisms.

Objective:

To evaluate three different media, including selective and nonselective media, in the detection of MRSA from clinical specimens of patients of an intensive care unit (ICU).

Patients:

Adult patients in the ICU of the Hospital Mae de Deus, Porto Alegre, Brazil.

Methods:

A total of 224 specimens were obtained from the nares of patients and plated on blood agar, mannitol sait agar containing 2 μg/mL of oxacillin (MSAO), and oxacillin resistance screening agar base (ORSAB). The presence of MRSA was investigated in typical colonies growing on the three types of media. Discrepant results were resolved by detection of themecA gene by polymerase chain reaction and the modified penicillin binding protein known as PBP2'.

Results:

MRSA was detected in 32 (14.3%) of 224 specimens. Blood agar, MSAO, and ORSAB detected MRSA in 17, 31, and 28 specimens, respectively. After the coagulase test, no false resistance was observed.

Conclusion:

MSAO and ORSAB performed equivalently in the detection of MRSA of colonized patients and require a single supplementary test (coagulase) to confirm MRSA.