bluuebunny/crossref_metadata_2025 huggingface dataset:
Colorful niches of phototrophic microorganisms shaped by vibrations of the water molecule
Authors: Stomp Maayke , Huisman Jef , Stal Lucas J , Matthijs Hans C P
Published: July 2007

The photosynthetic pigments of phototrophic microorganisms cover different regions of the solar light spectrum. Utilization of the light spectrum can be interpreted in terms of classical niche theory, as the light spectrum offers opportunities for niche differentiation and allows coexistence of species absorbing different colors of light. However, which spectral niches are available for phototrophic microorganisms? Here, we show that the answer is hidden in the vibrations of the water molecule. Water molecules absorb light at specific wavebands that match the energy required for their stretching and bending vibrations. Although light absorption at these specific wavelengths appears only as subtle shoulders in the absorption spectrum of pure water, these subtle shoulders create large gaps in the underwater light spectrum due to the exponential nature of light attenuation. Model calculations show that the wavebands between these gaps define a series of distinct niches in the underwater light spectrum. Strikingly, these distinct spectral niches match the light absorption spectra of the major photosynthetic pigments on our planet. This suggests that vibrations of the water molecule have played a major role in the ecology and evolution of phototrophic microorganisms.
Impact of the International Headache Society Criteria on the Use of Neuroimaging for Headache Diagnosis in a Headache Clinic
Authors: Fabbrini Giovanni , Barbanti Piero , Pascali Maria Paola , Lenzi Gian Luigi , Cerbo Rosanna
Published: July 2007

Objective.—To evaluate the impact of the introduction of the International Headache Society (IHS) criteria on the use of neuroimaging for headache diagnosis in a specialist outpatient center.

Background.—The general indications for neuroimaging in headache are a matter of debate. International Headache Society criteria should improve diagnostic accuracy, consequently reducing the use of expensive diagnostic procedures such as brain CT or MRI scan.

Methods.—We reviewed the medical records of all 2739 new patients seen in our center from 1984 to 1996, analyzing the records of those patients who underwent neuroimaging before or after the introduction of the IHS criteria in 1988.

Results.—There were no differences in the number of CT scans ordered in the period before (6.04%) or after (6.06%) the introduction of the IHS criteria. Only 12 scans revealed significant abnormalities, probably unrelated to headache.

Conclusions.—These results suggest that the yield of CT scanning patients seen in a headache clinic is very low, even when alarm signs are present notwithstanding strict adherence to diagnostic criteria. An improved definition of secondary forms of headache might help to reduce this adjunctive cost to the care of patients with headache in a headache clinic.
Group analysis and exact solutions of a class of variable coefficient nonlinear telegraph equations
Authors: Huang Ding-jiang , Ivanova Nataliya M.
Published: July 2007

A complete group classification of a class of variable coefficient (1+1)-dimensional telegraph equations f(x)utt=(H(u)ux)x+K(u)ux, is given, by using a compatibility method and additional equivalence transformations. A number of new interesting nonlinear invariant models which have nontrivial invariance algebras are obtained. Furthermore, the possible additional equivalence transformations between equations from the class under consideration are investigated. Exact solutions of special forms of these equations are also constructed via classical Lie method and generalized conditional transformations. Local conservation laws with characteristics of order 0 of the class under consideration are classified with respect to the group of equivalence transformations.
On noise processes and limits of performance in biosensors
Authors: Hassibi Arjang , Vikalo Haris , Hajimiri Ali
Published: July 2007

In this paper, we present a comprehensive stochastic model describing the measurement uncertainty, output signal, and limits of detection of affinity-based biosensors. The biochemical events within the biosensor platform are modeled by a Markov stochastic process, describing both the probabilistic mass transfer and the interactions of analytes with the capturing probes. To generalize this model and incorporate the detection process, we add noisy signal transduction and amplification stages to the Markov model. Using this approach, we are able to evaluate not only the output signal and the statistics of its fluctuation but also the noise contributions of each stage within the biosensor platform. Furthermore, we apply our formulations to define the signal-to-noise ratio, noise figure, and detection dynamic range of affinity-based biosensors. Motivated by the platforms encountered in practice, we construct the noise model of a number of widely used systems. The results of this study show that our formulations predict the behavioral characteristics of affinity-based biosensors which indicate the validity of the model.
Microstructures of SiC nanoparticle-doped MgB2∕Fe tapes
Authors: Zhu Y. , Matsumoto A. , Senkowicz B. J. , Kumakura H. , Kitaguchi H. , Jewell M. C. , Hellstrom E. E. , Larbalestier D. C. , Voyles P. M.
Published: July 2007

We have studied bulk MgB2 synthesized by reaction of MgH2 and B with and without SiC nanoparticles and at a range of reaction temperatures. All of the samples showed enhanced upper critical fields compared to most bulk MgB2, including the sample with 10at.% SiC reacted at 600°C, which showed Hc2(0K)>42T. Extensive transmission electron microscopy (TEM) and STEM observations show that using MgH2 instead of pure Mg reduces the concentration of oxide second phases in the tapes, but that adding SiC reintroduces nanoscale grains of MgO, SiO2, and SiOxCy, and larger grains of Mg2Si. SiC causes some C doping of the MgB2, but electron energy loss spectroscopy and x-ray diffraction measurements show that the C concentration is similar to other bulk C-doped MgB2. In all the samples with and without SiC, the grain size is very small, 10–60nm. Electron scattering from the high density of grains and second-phase boundaries is responsible for the enhanced Hc2 of these samples. However, the Hc2 properties are somewhat compromised by very broad transitions that may have their origin in the local variations of nanostructure.
Aggregation effects on two-photon absorption spectra of octupolar molecules
Authors: Liu Kai , Wang Yanhua , Tu Yaoquan , Ågren Hans , Luo Yi
Published: July 2007

Aggregation effects on two-photon absorption cross sections of an octupolar molecule, 1,3,5-triamino-2,4,6-trinitrobenzene, have been examined by means of density functional theory calculations in combination with molecular dynamic simulations. It is shown that this octupolar molecule becomes polar in solution and forms aggregates due to the presence of hydrogen bonding between molecules, which can induce a strong redshift of the charge-transfer state and significantly alter the TPA cross section.
Correlation between atomic orientation and product angular momentum alignment in the reaction of oriented Ar (P23) with CH3OH
Authors: Ohoyama H. , Matsumura T. , Yasuda K. , Watanabe D. , Kasai T.
Published: July 2007

Atomic orientation effect for the CH3O* formation has been studied for the dissociative energy transfer reaction of oriented Ar (P23) with CH3OH. The degree of polarization of CH3O* chemiluminescence was determined as a function of each magnetic MJ′ substate in the collision frame. A drastic change of the product angular momentum alignment due to atomic orientation was recognized.
Optical properties of (In,Ga)As capped InAs quantum dots grown on [11k] substrates
Authors: Mlinar V. , Peeters F. M.
Published: July 2007

Using three-dimensional k∙p calculation including strain and piezoelectricity, the authors showed that the size of the quantum dot (QD) in the growth direction determines the influence of the (In,Ga)As capping layer on the optical properties of [11k] grown InAs QDs, where k=1,2,3. For flat dots, increase of In concentration in the capping layer leads to a decrease of the transition energy, whereas for large dots an increase of the In concentration in the capping layer is followed by an increase of the transition energy up to a critical concentration of In, after which the optical transition energy starts to decrease.
Nonwoven electrowetting textiles
Authors: Bhat K. , Heikenfeld J. , Agarwal M. , Lvov Y. , Varahramyan K.
Published: July 2007

Electrowetting of two nonwoven textile platforms is reported. Demonstrated nonwoven textiles include a polyethylene naphthalate film that was laser milled with ∼125μm pores, and pressed paper that was made using wood microfibers of 35–50μm diameter. Vacuum deposition provided an Al electrode on the polymer textile whereas layer-by-layer nanoassembly provided an organic PEI-PEDOT:PSS electrode on the wood microfibers. Both textiles were electrically insulated with parylene C and fluoropolymer. Irreversible electrowetting of water was achieved over contact angles of ∼120° to ∼70° by applying 0–100V. Completely reversible electrowetting of water/oil was also demonstrated.
Theory of the dynamic response of a coplanar grid semiconductor detector
Authors: Kozorezov A. G. , Wigmore J. K. , Owens A. , Peacock A.
Published: July 2007

The authors have developed a theoretical model for the response of a coplanar grid semiconductor detector to hard x- and γ-ray radiation. Carrier drift trajectories were obtained by solving the coupled dynamical equations for carriers driven by electrostatic fields of the coplanar grid configuration. The pulse spectra calculated by summing the individual contributions for all carriers are compared to experimental results for a large volume optimized cadmium zinc telluride coplanar grid detector and good agreement is obtained.
Enhanced electroluminescence in polymer-nanotube composites
Authors: Lee Kyu Won , Lee S. P. , Choi H. , Mo Kyu Hyun , Jang Jae Won , Kweon H. , Lee Cheol Eui
Published: July 2007

Enhanced electroluminescence (EL) was observed with increasing carbon nanotube concentration in the MEH-PPV/SWCNT composites, where MEH-PPV and SWCNTs correspond to poly[2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylene-vinylene] and single-walled carbon nanotubes, respectively. Spatially separated conduction paths of the two distinct charge carriers, induced by blending SWCNTs with MEH-PPV, may explain the enhanced EL.
Broadband dielectric spectroscopy on single-crystalline and ceramic CaCu3Ti4O12
Authors: Krohns S. , Lunkenheimer P. , Ebbinghaus S. G. , Loidl A.
Published: July 2007

The authors present dielectric measurements of the colossal dielectric constant material CaCu3Ti4O12 extending up to 1.3GHz also covering so far only rarely investigated single-crystalline samples. Special emphasis is put on the second relaxation reported in several works on polycrystals, which the authors detect also in single crystals. For polycrystalline samples, the authors provide a recipe to achieve values of the dielectric constant as high as in single crystals.
Single point defect photonic crystal nanocavity with ultrahigh quality factor achieved by using hexapole mode
Authors: Tanabe Takasumi , Shinya Akihiko , Kuramochi Eiichi , Kondo Shingo , Taniyama Hideaki , Notomi Masaya
Published: July 2007

Photonic crystal (PhC) nanocavities with an extremely high quality factor (Q) based on a point defect are fabricated and their properties are studied. Their confinement of light is based on rotational symmetry, which forms a hexapole mode with a Q of 3.2×105. It demonstrates that this nanocavity is an alternative candidate for achieving an ultrahigh Q. In addition, we observed bistable behavior based on the thermo-optic effect at a threshold power of a few 100μW. We also investigated the dynamic properties of this cavity, where we observed that the cavity exhibits a smaller Q at a higher input power.
Germanium near infrared detector in silicon on insulator
Authors: Colace L. , Sorianello V. , Balbi M. , Assanto G.
Published: July 2007

The authors demonstrate near infrared photodetectors in evaporated germanium on silicon-on-insulator waveguides. The authors achieve peak responsivities as high as 1A∕W and dark current densities as low as 40nA at a reverse bias of 1V. Owing to the low deposition temperature, this technology allows for simple and low cost monolithic integration with silicon.
Percolative conductor/polymer composite films with significant dielectric properties
Authors: Chen Qian , Du Piyi , Jin Lu , Weng Wenjian , Han Gaorong
Published: July 2007

A percolative film with conductive acetylene black introduced into β-polyvinylidene fluoride was prepared by dip-coating method. Percolation theory was employed to explain the dielectric behavior of polymer/conductor composite films. Experimental results showed that the dielectric constant of polymer/conductor composite films can reach 56 and the dielectric loss is below 0.15 when acetylene black concentration is in the neighborhood of percolation threshold (fc). The experimental results are in good agreement with classic percolation power law, with fc≈1.3% and exponent q≈0.53. Such composite films have a potential to become capacitors and can be easily fabricated due to its flexibility.
Metal and dielectric duality for an aligned Al nanorod array
Authors: Jen Yi-Jun , Yu Ching-Wei
Published: July 2007

In this letter, aluminum (Al) is used to make a narrow rod array (NRA) by oblique angle deposition method. The Al NRA film exhibits both metallic and dielectric optical characteristics. Like metal films, the Al NRA film only weakly disperses visible wavelength of normally incident light. However, strong interference causes the obliquely incident s-polarized and p-polarized lights to resonate in the Al NRA film. Even though the optical constant of the Al NRA film is dielectriclike, the surface plasmon wave excited and propagating on the surface of Al NRA is demonstrated to be responsible for the p-polarized resonance.
The receptor-like kinase SERK3/BAK1 is a central regulator of innate immunity in plants
Authors: Heese Antje , Hann Dagmar R. , Gimenez-Ibanez Selena , Jones Alexandra M. E. , He Kai , Li Jia , Schroeder Julian I. , Peck Scott C. , Rathjen John P.
Published: July 2007

In pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI), plant cell surface receptors sense potential microbial pathogens by recognizing elicitors called PAMPs. Although diverse PAMPs trigger PTI through distinct receptors, the resulting intracellular responses overlap extensively. Despite this, a common component(s) linking signal perception with transduction remains unknown. In this study, we identify SOMATIC EMBRYOGENESIS RECEPTOR KINASE (SERK)3/brassinosteroid-associated kinase (BAK)1, a receptor-like kinase previously implicated in hormone signaling, as a component of plant PTI. In
Arabidopsis thaliana
, AtSERK3/BAK1 rapidly enters an elicitor-dependent complex with FLAGELLIN SENSING 2 (FLS2), the receptor for the bacterial PAMP flagellin and its peptide derivative flg22. In the absence of
AtSERK3/BAK1
, early flg22-dependent responses are greatly reduced in both
A. thaliana
and
Nicotiana benthamiana
. Furthermore,
N. benthamiana Serk3/Bak1
is required for full responses to unrelated PAMPs and, importantly, for restriction of bacterial and oomycete infections. Thus,
SERK3/BAK1
appears to integrate diverse perception events into downstream PAMP responses, leading to immunity against a range of invading microbes.
Finite group extensions and the Atiyah conjecture
Authors: Linnell Peter , Schick Thomas
Published: July 2007

The Atiyah conjecture for a discrete groupGGstates that theL2L^2-Betti numbers of a finite CW-complex with fundamental groupGGare integers ifGGis torsion-free, and in general that they are rational numbers with denominators determined by the finite subgroups ofGG. Here we establish conditions under which the Atiyah conjecture for a torsion-free groupGGimplies the Atiyah conjecture for every finite extension ofGG. The most important requirement is thatH∗(G,Z/p)H^*(G,\mathbb {Z}/p)is isomorphic to the cohomology of thepp-adic completion ofGGfor every prime numberpp. An additional assumption is necessary e.g. that the quotients of the lower central series or of the derived series are torsion-free. We prove that these conditions are fulfilled for a certain class of groups, which contains in particular Artin’s pure braid groups (and more generally fundamental groups of fiber-type arrangements), free groups, fundamental groups of orientable compact surfaces, certain knot and link groups, certain primitive one-relator groups, and products of these. Therefore every finite, in fact every elementary amenable extension of these groups satisfies the Atiyah conjecture, provided the group does. As a consequence, if such an extensionHHis torsion-free, then the group ringCH\mathbb {C}Hcontains no non-trivial zero divisors, i.e.HHfulfills the zero-divisor conjecture. In the course of the proof we prove that if these extensions are torsion-free, then they have plenty of non-trivial torsion-free quotients which are virtually nilpotent. All of this applies in particular to Artin’s full braid group, therefore answering question B6 on http://www.grouptheory.info. Our methods also apply to the Baum-Connes conjecture. This is discussed by Thomas Schick in his preprint “Finite group extensions and the Baum-Connes conjecture”, where for example the Baum-Connes conjecture is proved for the full braid groups.
Lower bounds on volumes of hyperbolic Haken 3-manifolds
Authors: Agol Ian , Storm Peter , Thurston William
Published: July 2007

We prove a volume inequality for 3-manifolds having

C

0

C^{0}

metrics “bent” along a surface and satisfying certain curvature conditions. The result makes use of Perelman’s work on the Ricci flow and geometrization of closed 3-manifolds. Corollaries include a new proof of a conjecture of Bonahon about volumes of convex cores of Kleinian groups, improved volume estimates for certain Haken hyperbolic 3-manifolds, and a lower bound on the minimal volume of orientable hyperbolic 3-manifolds. An appendix compares estimates of volumes of hyperbolic 3-manifolds drilled along a closed embedded geodesic with experimental data.
Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish
Authors: Davis M. W.
Published: July 2007

Davis, M. W. 2007. Simulated fishing experiments for predicting delayed mortality rates using reflex impairment in restrained fish. – ICES Journal of Marine Science, 64: 1535–1542. Development of efficient methods to predict discard and escapee mortality in fishing operations is essential to the conservation of sensitive fish stocks. For a few fisheries, mortality data are available from fishing experiments in the field; these require long-term holding or monitoring of fish in tanks, cages, or tag and recapture experiments to detect delayed mortality. A different approach to predicting discard and escapee mortality is to use reflex action mortality predictors (RAMP) consisting of relationships between mortality and reflex impairment for species of interest. Fish were towed in a net in the laboratory and then either restrained in foam-lined holders and rapidly tested for reflex impairment five minutes after towing, or held for up to 60 days to determine delayed mortality. Delayed mortality occurred up to 20 days after towing. RAMP was related to mortality with biphasic sigmoid functions. As fishing stressors increased in intensity, the first phase showed an increase in RAMP with no concomitant mortality. In the second phase, RAMP continued to increase, while mortality became apparent and increased. The measurement of RAMP in restrained fish on board fishing vessels during experiments to predict discard mortality and in caged free swimming fish to predict escapee mortality is feasible and advisable.
A Severe Disease of Tomato in the Culiacan Area (Sinaloa, Mexico) Is Caused by a New Picorna-Like Viral Species
Authors: Turina M. , Ricker M. D. , Lenzi R. , Masenga V. , Ciuffo M.
Published: July 2007

We were able to mechanically transmit a small isometric virus from field tomato samples showing severe necrotic symptoms, collected in the Culiacan area of Sinaloa state (Mexico). After gradient purification and three rounds of single-lesion passage on Chenopodium quinoa, the virus was back-inoculated to tomato plants and reproduced the original apical necrosis symptoms. The virus could be transmitted to a wide range of experimental hosts, including a number of solanaceous plants. Purified virus was used to produce specific polyclonal rabbit antibodies and serological tests such as enzyme-linked immunosorbent assay, Western blot analysis, and an immunochromatographic lateral flow assay. Such assays confirmed the wide distribution of this virus in symptomatic field plants in the area of the epidemic. Purified particles contained two genomic RNA molecules of ca. 7 kb (RNA1) and 5 kb (RNA2) estimated length. Analysis of clones from a cDNA library provided 6.5 and 3.0 kb of sequence for RNA1 and RNA2, respectively. Sequence analysis of the encoded replicase showed greatest similarity with members of the Sequiviridae family, and indicated that the virus we isolated is a new virus species, provisionally named Tomato apex necrosis virus.
Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2005
Authors: Kolmer J. A. , Long D. L. , Hughes M. E.
Published: July 2007

Collections of Puccinia triticina were obtained from rust-infected wheat leaves by cooperators throughout the United States and from surveys of wheat fields and nurseries in the Great Plains, Ohio River Valley, southeast, California, and Washington State, in order to determine the virulence of the wheat leaf rust population in 2005. Single uredinial isolates (797 in total) were derived from the collections and tested for virulence phenotype on lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes Lr1, Lr2a, Lr2c, Lr3a, Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr18, Lr21, Lr28, and winter wheat lines with genes Lr41 and Lr42. In the United States in 2005, 72 virulence phenotypes of P. triticina were found. Virulence phenotype TDBGH, selected by virulence to resistance gene Lr24, was the most common phenotype in the United States, and was found throughout the Great Plains region. Virulence phenotype MCDSB with virulence to Lr17a and Lr26 was the second most common phenotype and was found widely in the wheat growing regions of the United States. Virulence phenotype MFPSC, which has virulence to Lr17a, Lr24, and Lr26, was the third most common phenotype, and was found in the Ohio Valley region, the Great Plains, and California. The highly diverse population of P. triticina in the United States will continue to present a challenge for the development of wheat cultivars with effective durable resistance to leaf rust.
A Rapid Technique for Determination of Races of Phytophthora nicotianae on Tobacco
Authors: Gutiérrez Walter A. , Mila Asimina L.
Published: July 2007

A laboratory technique for determining races of Phytophthora nicotianae on tobacco (Nicotiana tabacum) was developed and compared with a commonly used greenhouse method. The laboratory technique was based on production and inoculation of tobacco seedlings in tissue culture plates. Three P. nicotianae isolates from North Carolina previously determined as race 0 and 1 were used. Four tobacco cultivars and two breeding lines with different types of resistance were used as differential cultivars: K-326, K-346, NC-71, NC-1071, L8, and Ky14xL8. Plants were evaluated 7 and 14 days after inoculation. Five differential cultivars (K-326, K-346, NC-1071, NC-71, and L8) were determined to be sufficient to differentiate races 0 and 1. Cv. Ky14xL8 was ineffective for differentiation of races and produced inconsistent results. The laboratory technique was as effective as the greenhouse technique for distinguishing different races of P. nicotianae for every isolate in all experiments. Additionally, the most reliable results for both methods were obtained when evaluations were made 14 days after inoculation. The laboratory technique was validated with 21 isolates collected from four counties in North Carolina. The laboratory technique produced results 2 weeks faster than the greenhouse technique and required significantly less space and labor than the greenhouse technique for the same number of isolates. Additionally, the larger number of seedlings used in the laboratory technique increased the robustness of the results, especially for isolates for which race identification was unclear with the greenhouse technique. We propose that the laboratory technique has the potential for evaluation of tobacco resistance in other pathosystems as well.
Evaluation of Lisianthus Cultivars for Resistance toBotrytis cinerea
Authors: Wegulo Stephen N. , Vilchez Miguel
Published: July 2007

Lisianthus (Eustoma grandiflorum) is a high-value cut flower. However, major yield losses often result from gray mold caused by Botrytis cinerea. Various techniques were used to evaluate 12 lisianthus cultivars for resistance B. cinerea. Disease evaluations from detached leaf, leaf disc, cut stem, and in vivo growth chamber stem (GC) assays were correlated with those from an in vivo greenhouse stem (GH) assay, in which commercial greenhouse production of lisianthus was simulated. In all assays, stems or leaves were wounded before inoculation with spores or mycelia of B. cinerea. There was a significant (P ≤ 0.03) positive correlation between stem lesion length in the GH assay and disease incidence in the same assay (R = 0.74), stem lesion length from spore spray inoculation in the GC assay (R = 0.62), and percent necrosis from spore spray inoculation of detached leaves (R = 0.71). Correlations between stem lesion length in the GH assay and disease evaluations from spore drop and mycelial inoculation of detached leaves, leaf discs, and cut stems were not significant at P = 0.05. Considering only screening methods with significant correlations, ‘Magic Champagne’ was the most resistant cultivar (mean rank [mr] = 2 of 12). ‘Echo White’ and ‘Echo Lavender’ were the least resistant cultivars (mr = 11). The other cultivars were ‘Magic White’ (mr = 4); ‘Avila Ivory’, ‘Balboa Yellow’, ‘Echo Pink’, and ‘Magic Rose’ (mr = 5); ‘Balboa Blue’ (mr = 6); ‘Avila Blue Rim’ (mr = 8); and ‘Avila Purple’ and ‘Catalina Purple’ (mr = 9). The results from this study indicate that in vivo disease incidence, in vivo stem assays, and detached leaf assays, all initiated with wounding followed by spore spray inoculation, may be more reliable in evaluating lisianthus cultivars for resistance to B. cinerea than spore drop and mycelial inoculation of detached leaves, leaf discs, and cut stems. The results also indicate that lisianthus cultivars with moderate resistance to B. cinerea are commercially available. These cultivars have potential for use as germplasm in breeding lisianthus for resistance to the pathogen.
A New Pathotype of Meloidogyne chitwoodi Race 1 from Washington State
Authors: Mojtahedi H. , Brown C. R. , Riga E. , Zhang L. H.
Published: July 2007

Meloidogyne chitwoodi Golden et al. is a serious pest of potato (Solanum tuberosum L.), and is widespread in the Pacific Northwest United States. M. chitwoodi is currently reported to consist of two host races and one pathotype (2,3) that are not distinguished morphologically. Host race 1 reproduces on Chantenay carrot but not on Thor alfalfa and host race 2 reproduces on alfalfa but not on carrot. Both races fail to reproduce on roots of S. bulbocastanum, a wild potato species used as a source of resistance in our breeding program (1). The resistance to race 1 in S. bulbocastanum is attributed to Rmc1(blb) gene. Pathotype 1 of race 2 breaks resistance and reproduces on S. bulbocastanum (2). We have tested resistant breeding lines repeatedly in Prosser, WA field plots infested with MC race 1 and harvested tubers free from M. chitwoodi damage. In 2004 however, tubers of some resistant lines were damaged by the M. chitwoodi population that did not cause damage in the past. Populations of M. chitwoodi were established on tomato by adding peels obtained from the infected tubers of resistant lines. The reproductive factor, final number of eggs ÷ initial inoculum, of the new population was determined on five replications of 3-week-old Chantenay carrot and Thor alfalfa. Five thousand eggs were extracted from nematode cultures reared on tomatoes and then were added around the root system of the test plants. The plants were maintained in the greenhouse for 55 days before the nematode eggs were extracted and RF (reproductive factor = final/initial population) values determined. Like the MC race 1, new populations reproduced on Chantenay carrot (RF > 1) but failed to reproduce on Thor alfalfa (RF < 0.1). Unlike MC race 1, the new populations reproduced on roots of all breeding lines that carried Rmc1(blb) gene (RF > 1). These results suggest that the selected population of M. chitwoodi in the Prosser site is a new pathotype, which is designated pathotype 1 of MC race 1.

References: (1) C. R. Brown et al. Am. J. Potato Res. 83:1, 2006. (2) H. Mojtahedi et al. J. Nematol. 30:506, 1998. (3) G. S. Santo et al. Plant Dis. 69:361, 1985.
Occurrence of Fusarium solani on Blueberry in Argentina
Authors: Pérez B. A. , Murillo F. , Divo de Sesar M. , Wright E. R.
Published: July 2007

Blueberry plants with root rot and sudden death symptoms were collected in Concordia, Entre Ríos. Diseased roots were disinfected by immersion in 0.5% NaOCl for 2 min, cut into pieces, transferred to carrot agar (CA), and maintained at 20 ± 2°C and 12 h of near UV light (Philips Black Light lamps TL 40W/08). Conidia were identified with an Olympus BX-51 optical microscope by using a CoolSNAP Pro digital kit with image-pro plus and color digital camera (Media Cybernetics, Inc., Silver Spring, MD). Macroconidia length was variable, 3.9 μm and as much as 29 μm (1 to 5 septa), and microconidia measured 3.8 × 11 μm. Fungal description agrees with Fusarium solani (1). Pathogenicity of the purified isolate was evaluated on 2-month-old plants (cvs. Misty and Sharp Blue). The purified, grayish white isolate was grown on CA for 7 days, and mycelial plugs were placed next to the base of wounded stem and roots immediately below the potting mix soil line. Plants were maintained in the dark at 20 ± 2°C and 90% humidity for 48 h, and then transferred to 12 h of light. Wounded plants with CA plugs served as controls. Dark spots along the stem and root and stem rot appeared 7 to 21 days after inoculation. Controls remained symptomless. The fungus was reisolated from inoculated plants. Fusarium sp. was previously cited (2). To our knowledge, this is the first report of F. solani on blueberry in Argentina.

References: (1) C. Booth. Fusarium. Laboratory Guide to the Identification of the Major Species. CMI, Kew, England, 1977. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.
First Report of Leaf Spot, Blight, and Stem Lesions Caused by Cylindrocladium pauciramosum on Callistemon in Spain
Authors: Pérez-Sierra A. , Álvarez L. A. , León M. , Abad-Campos P. , Armengol J. , García-Jiménez J.
Published: July 2007

Callistemons (Callistemon citrinus (Curtis) Skeels), evergreen plants of the family Myrtaceae, are commonly grown in Mediterranean gardens for their red bottlebrush-like flowers. During November of 2006, 1-year-old potted plants of callistemon showed leaf spots and blight in commercial nurseries in Valencia, Spain. Symptoms consisted initially of minute brown spots on the leaves, developing into black-gray blotches that finally coalesced. Diseased plants also showed stem lesions and blight of young shoots. Approximately 30% of the plants were affected. A Cylindrocladium sp. was isolated consistently from the infected tissues. Six single conidial isolates were grown on carnation leaf agar (CLA) under near-UV light at 25°C for 7 days (1). The macroconidiophores comprised of a stipe, a sterile elongation, and a penicillated arrangement of primary, secondary, and tertiary branches. The stipes were septate, 110 to 175 (138) μm long, with a terminal obpyriform vesicle measuring 3.75 to 7.5 (5.8) μm wide. Phialides (12.5 × 3.6 μm) were hyaline, doliiform to reniform, with conidia 40 to 55 × 3.7 to 5 μm, cylindrical with rounded ends, aseptate or one septate. Chlamydospores were brown and formed microsclerotia. These features conformed to the description of Cylindrocladium pauciramosum (3). Further confirmation was obtained by sequence analysis. The 5′ end of the β-tubulin gene was amplified using primers T1 and βt2b (2). Comparison with other sequences in GenBank revealed that the isolates described here were identical with C. pauciramosum (Accession No. AY880064) isolated from Ceanothus in the UK. To confirm pathogenicity, 1-year-old plants of callistemon were inoculated with two isolates by spraying with a spore suspension of the fungus (1 × 105 conidia per ml) obtained from 14-day-old single spore colonies on CLA. Control plants were treated with sterile distilled water. After inoculation, all plants were maintained in plastic bags and kept at 22 ± 2°C. Four days after inoculation, the plants developed symptoms similar to those observed in natural infections, and C. pauciramosum was reisolated, successfully completing Koch's postulates. No symptoms were observed on the control plants. C. pauciramosum has been recorded on several hosts, including Callistemon citrinus, in Italy (4). To our knowledge, this is the first report of C. pauciramosum on callistemon in Spain.

References: (1) P. W. Crous and M. J. Wingfield. Mycotaxon 51:341, 1994. (2) B. Henricot and A. Culham. Mycologia 94:980, 2002. (3) C. L. Schoch et al. Mycologia 91:286, 1999. (4) C. L. Schoch et al. Plant Dis. 85:941, 2001.
Factors influencing fish catch levels on Kenya's coral reefs
Authors: Mangi S. C. , Roberts C. M.
Published: July 2007

Abstract  The factors influencing fish catches on Kenya's coral reefs were studied. Catch data were collected at the species level by counting the number of fish landed at each landing site of each fishing ground. Live coral cover, topographic complexity, fish and sea urchin density, and the number of fishers and gear units used in each fishing ground were compared with catch data. Fishing grounds included one location where only basket traps were allowed, six locations where all gear types were used except beach seines, and three locations where all types of gear, including beach seines, were used. Catch and effort variables were similar across the fishing grounds whereas live coral cover and sea urchin density differed (P < 0.01). The sites fished by all types of gear including beach seines had the lowest coral cover (8.4 ± 0.9%) and topographic complexity (1.12 ± 0.01). Catch levels were positively correlated with the number of fishers and fish density but not with the number of gear units deployed or sea urchin density. The number of fishers and live coral cover were the strongest factors determining total catch levels. The results suggest that high levels of fishing effort coupled with the use of destructive gear types, exacerbate the effects of overfishing on Kenya's reefs.
A randomized, double‐blind trial demonstrating bioequivalence of the current recombinant activated factor VII formulation and a new robust 25°C stable formulation
Authors: BYSTED B. V. , SCHARLING B. , MØLLER T. , HANSEN B. L.
Published: July 2007

Summary.  Recombinant activated factor VIIa (rFVIIa) is a well‐established treatment for bleeding episodes in patients with congenital or acquired haemophilia A or B with inhibitors to factors VIII and IX and patients with FVII deficiency. The aim of this trial was to demonstrate bioequivalence between the currently marketed (rFVIIa/NovoSeven®) and a new rFVIIa formulation (VII25) stable at up to 25°C. Furthermore, short‐term safety and tolerability of VII25 and pharmacokinetics of both formulations were investigated. In this single‐centre, randomized, double‐blind, two‐way cross‐over trial, healthy male subjects received one intravenous bolus injection of rFVIIa and one of VII25, both at 90 μg kg−1, in a randomized order 2–3 weeks apart. Mean VII25/rFVIIa ratio for area under the plasma activity‐time curve from time 0 to last quantifiable activity (primary bioequivalence endpoint), was 0.93, 90% confidence interval (CI) (0.89–0.96), within the predefined bioequivalence range (0.80–1.25). Secondary pharmacokinetic parameters were comparable between formulations. No serious adverse events were observed. Six mild or moderate treatment‐emergent adverse events were reported in five subjects. Coagulation‐related parameter profiles were similar between rFVIIa and VII25. No clinically abnormal changes were observed for laboratory parameters and no subjects developed FVIIa antibodies. This trial demonstrated bioequivalence between the currently available rFVIIa and VII25 stable at up to 25°C. VII25’s ‘user‐friendly’ formulation removes the inconvenience of storing/transporting at 2–8°C, and as the drug substance is the same, the activity and safety established for rFVIIa is maintained.
Pure red cell aplasia due to parvovirus B19 infection transmitted probably through hematopoietic stem cell transplantation
Authors: Wąsak‐Szulkowska E. , Grabarczyk P. , Rzepecki P.
Published: July 2007

Abstract: Human parvovirus B19 is a very common infectious pathogen in humans. In healthy subjects, B19 infection is the cause of a self‐limiting subclinical erythroid aplasia, followed by rash or arthralgia. In immunocompromised patients B19 can cause chronic anemia. This report presents the case of a 19‐year‐old male who developed severe anemia shortly after successful allogeneic hematopoietic stem cell transplantation. His marrow showed selective erythroid aplasia, and real‐time polymerase chain reaction assay confirmed parvovirus B19 infection. Despite repeated high‐dose immunoglobulin treatment, he remained anemic. His hematological status markedly improved after cessation of immunosuppression. Retrospective examination of the donor's blood suggests that hematopoietic stem cells could be the source of infection.
Does a full bladder aid upper tract visualization in magnetic resonance urography?
Authors: Colville JAC , Killeen RPM , Buckley O , Geoghegan T , Regan F , Hamilton S , Torreggiani WC
Published: July 2007

The aim of this study was to evaluate whether a full bladder improved the visualization of the upper renal tract during magnetic resonance urography (MRU). Twenty volunteers were recruited into the study. The MRU imaging was carried out on a 1.5‐T MR system. Imaging was carried out in the coronal plane using a half‐Fourier acquired single‐shot turbo‐spin‐echo technique. All volunteers were examined in two separate MRU studies to visualize the urinary tract. The first study was carried out with a ‘full’ bladder followed by a study with an ‘empty’ bladder, leading to a total of 40 examinations. Two radiologists then reviewed maximum intensity projection images from both ‘full’ and ‘empty’ studies independently. Both left and right upper tracts were divided into five segments. A three‐point grading system was used to evaluate visualization. Excellent visualization = 3, good visualization = 2 and poor visualization = 1. Maximum score per patient was 30. Results were tabulated and analysed using an Excel database. The average score for visualization for the ‘full’ bladder group was 22.1/30 (73.8%) and the average score for the empty bladder was 16.2/30 (54%). Overall improvement in visualization was 5.9/30 (19.8%). There was strong interobserver agreement, with a concordance value of 92.5%. The MRU carried out in healthy young adult volunteers with a full bladder allows improved visualization of the upper tracts.
Diagnostic accuracy of 16‐slice CT coronary angiography in the evaluation of coronary artery disease
Authors: Soon KH , Chaitowitz I , Cox N , MacGregor L , Eccleston D , Bell KW , Kelly A‐M , Lim YL
Published: July 2007

Multislice CT coronary angiography (CT‐CA) has emerged as a potential imaging method for coronary artery disease. This study aimed to ascertain the accuracy of 16‐slice CT in the diagnosis of significant coronary stenosis (≥50% reduction of lumen diameter). This mixed retrospective/prospective observational study compared 95 paired 16‐slice CT‐CA and fluoroscopic coronary angiography (FCA) sets. A cardiologist and a radiologist blinded to the FCA findings evaluated CT‐CA images independently by visual estimation. Disagreement between these reporters was arbitrated by a third CT reporter (a cardiologist). A separate cardiologist blinded to CT‐CA findings assessed FCA by visual estimation. Of 1161 coronary segments assessable on FCA, 1103 segments (95%) were assessable on CT‐CA. The CT‐CA correctly diagnosed 147/180 segments with significant stenoses (sensitivity = 82%) and correctly identified 874/923 coronary segments without significant stenoses (specificity = 95%). The positive and negative predictive values of CT‐CA in the diagnosis of coronary segment with significant stenosis were 75 and 96%, respectively. On patient‐based analysis, CT‐CA correctly identified all 68 studies with at least one vessel with significant stenosis (sensitivity = 100%; specificity = 83%). The positive and negative predictive values of CT‐CA in identifying patients with significant coronary stenosis were 94 and 100%, respectively. The 16‐slice CT‐CA showed moderately good sensitivity but very high specificity and negative predictive value in the diagnosis of significant coronary stenosis. The CT‐CA would appear to be a useful ‘rule‐out’ test for patients with low‐risk profile for ischaemic heart disease.
Magnetic resonance imaging of cauda equina syndrome in long‐standing ankylosing spondylitis
Authors: Arslanoglu A , Aygun N
Published: July 2007

The cauda equina syndrome is an uncommon complication of long‐standing ankylosing spondylitis and its aetiology is controversial. We report a case of the cauda equina syndrome, erosion of the posterior elements of the lumbar spine and traction of the lumbar nerve roots because of multiple dural diverticula in a patient with long‐standing ankylosing spondylitis. Magnetic resonance imaging is valuable in excluding other spinal lesions. Extensive dural diverticula formation is characteristic of ankylosing spondylitis and has the potential to provide an early diagnosis.
Medical student radiology teaching in Australia and New Zealand
Authors: Subramaniam RM , Kim C , Scally P
Published: July 2007

This study, involving 19 centres, establishes the status of medical student radiology teaching in Australia and New Zealand. It aims to document the academic and clinical staff profile involved in teaching, to indicate the methods of instructions used, to outline the available radiology library resources for medical students, to list the textbooks used in teaching and to uncover how many radiology departments are involving medical students in research. The findings can be used to plan and execute further actions that will enhance radiology teaching of medical students.
L‐carnitine supplementation in the dialysis population: Are Australian patients missing out? (Review Article)
Authors: REUTER STEPHANIE E , FAULL RANDALL J , EVANS ALLAN M
Published: July 2007

SUMMARY:  It has been widely established that patients with end‐stage renal disease undergoing chronic haemodialysis therapy exhibit low endogenous levels of L‐carnitine and elevated acylcarnitine levels; however, the clinical implication of this altered carnitine profile is not as clear. It has been suggested that these disturbances in carnitine homeostasis may be associated with a number of clinical problems common in this patient population, including erythropoietin‐resistant anaemia, cardiac dysfunction, and dialytic complications such as hypotension, cramps and fatigue. In January 2003, the Centers for Medicare and Medicaid Services (USA) implemented coverage of intravenous L‐carnitine for the treatment of erythropoietin‐resistant anaemia and/or intradialytic hypotension in patients with low endogenous L‐carnitine concentrations. It has been estimated that in the period of 1998–2003, 3.8–7.2% of all haemodialysis patients in the USA received at least one dose of L‐carnitine, with 2.7–5.2% of patients receiving at least 3 months of supplementation for one or both of these conditions. The use of L‐carnitine within Australia is virtually non‐existent, which leads us to the question: Are Australian haemodialysis patients missing out? This review examines the previous research associated with L‐carnitine administration to chronic dialysis patients for the treatment of anaemia, cardiac dysfunction, dyslipidaemia and/or dialytic symptoms, and discusses whether supplementation is warranted within the Australian setting.
Urine interleukin‐1β in children with acute pyelonephritis and renal scarring
Authors: SHEU JI‐NAN , CHEN MENG‐CHI , CHENG SUN‐LONG , LEE IN‐CHI , CHEN SHAN‐MING , TSAY GREGORY JIAZER
Published: July 2007

Aim:  Acute pyelonephritis is a common infectious disease in children and can result in permanent renal damage. Interleukin (IL)‐1β is an important inflammatory mediator that appears early during bacterial infection. This prospective study examined urine IL‐1β levels in children with acute pyelonephritis documented by 99mTc‐dimercaptosuccinic acid (DMSA) scan, and also evaluated whether this cytokine correlated with renal scarring.

Methods:  A total of 75 children aged 1–121 months with a diagnosis of first‐time febrile urinary tract infection (UTI) were studied. The following inflammatory markers were assessed: fever, white blood cell (WBC), neutrophil, C‐reactive protein (CRP) and urine IL‐1β. Urine samples were collected for IL‐1β measurement by enzyme‐linked immunosorbent assay before and after antibiotic treatment of the infection. Follow‐up DMSA scan was performed at 6–12 months after the acute pyelonephritis to detect renal scarring. Twenty children with other febrile illnesses served as non‐renal febrile controls.

Results:  The 75 children were divided into acute pyelonephritis (n = 41) and lower UTI (n = 34) groups according to the findings of DMSA scans. Fever, WBC count, neutrophil count and CRP were significantly higher in the children with acute pyelonephritis than in those with lower UTI (all P < 0.001). The initial urine IL‐1β levels of children with acute pyelonephritis were significantly higher when compared with lower UTI and non‐renal febrile controls (P < 0.001). Urine IL‐1β in children with acute pyelonephritis was positively correlated with fever, CRP, WBC, neutrophil and leucocyturia. Renal scarring was found in 12 (29.3%) of the 41 children with acute pyelonephritis. The mean age was significantly lower in the children with renal scarring compared with those without (P < 0.05).

Conclusion:  These results have shown that urine IL‐1β level may serve as a useful marker for the early detection of acute pyelonephritis in febrile children. Young children are at a risk of the development of renal scarring following acute pyelonephritis.