bluuebunny/crossref_metadata_2025 huggingface dataset:
First-principles study of contact between Ti surface and semiconducting carbon nanotube
Authors: Meng Tiezhu , Wang Chong-Yu , Wang Shan-Ying
Published: July 2007

The electronic structure of contact between Ti surface and a semiconducting carbon nanotube is investigated by using first-principles method. The nanotube placed on the Ti surface exhibits obvious cross section distortion and strong chemical bonds form between C and Ti. Our results suggest that the nanotube may become metallic and the electrons can be transferred from the nanotube to the Ti electrode without any electrostatic potential barrier. The results are quite different from those of semiconducting carbon nanotube on Al surface, given that Al and Ti have similar work functions. This difference can explain the unexpected experimental difference between Al-nanotube contact and Ti-nanotube contact.
Modeling the formation of strong couples in high temperature liquid
Authors: Yaghmaee M. S. , Shokri B.
Published: July 2007

The study of atomic/molecular level interactions in the liquid state of materials not only helps us to understand the extreme behavior of such complex liquid phases (different from what we observe from ideal systems), but also helps us to analyze and design the advanced materials. For this reason, the model of an ideally associated mixture has been applied to describe the equilibrium state on the example of an Fe-rich corner of the quaternary Fe–Al–N–B system. This model is able to formulate and analyze the state of liquid systems, which are rich in one component and which also have other components that develop strong interactions among each other, leading to the formation of some couples in the system. These couples could be as small as a two-atom structure (such as simple compounds in a metallic system), but they could also become larger up to nanoscale due to higher stoichiometric morphologies that form nanoscale clusters. The solubility of AlN, BN, and N2 gases in the liquid phase of the ternary Fe–Al–N and Fe–B–N systems has been calculated and fitted to experimental results. There is a deviation between our calculated boundary curves fitted with experimental result and those extrapolated curves from the concept of solubility product, which may only be attributed to the misleading concept of solubility product that ignores couple formation in the liquid. Applying this model to the Fe–Al–N–B liquid system, we found that at relatively low boron content (i.e., 20–30ppm) and soluble aluminum content exceeding 250ppm, more than 90% of the steel making practice with nitrogen content (i.e., maximum of 120ppm) is complexed into AlN and BN couples at temperatures falling in the range of 1823–1923K. The model describing the liquid quaternary Fe–Al–N–B system provides us a tool to determine the equilibrium quantity of the considered constituents (free atoms and couples) formed in the liquid, as a function of macroscopic composition and temperature. This algorithm can be used generally for high temperature multicomponent liquid systems, which have the tendency to form strong couples or nanoclusters.
Magnetic anisotropies in ultrathin iron films grown on the surface-reconstructed GaAs substrate
Authors: Aktaş B. , Heinrich B. , Woltersdorf G. , Urban R. , Tagirov L. R. , Yıldız F. , Özdoğan K. , Özdemir M. , Yalçin O. , Rameev B. Z.
Published: July 2007

Magnetic anisotropies of epitaxial ultrathin iron films grown on the surface-reconstructed GaAs substrate were studied. Ferromagnetic resonance technique was exploited to determine magnetic parameters of the films in the temperature range of 4–300K. Extraordinary angular dependence of the FMR spectra was explained by the presence of fourfold and twofold in-plane anisotropies. A strong in-plane uniaxial anisotropy with magnetic hard axis along the [11¯0] crystallographic direction is present at the GaAs∕Fe(001) interface while a weak in-plane uniaxial anisotropy for the Fe grown on Au has its easy axis oriented along [11¯0]. A linear dependence of the magnetic anisotropies as a function of temperature suggests that the strength of the in-plane uniaxial anisotropy is affected by the magnetoelastic anisotropies and differential thermal expansion of contacting materials.
Microstructural evolution, atomic migration, and FePt nanoparticle formation in ion-irradiated Pt(Fe)/C(Fe) multilayers
Authors: Bera S. , Roy S. , Bhattacharjee K. , Kuri G. , Dev B. N.
Published: July 2007

Ion-irradiation-induced microstructural modifications, atomic migration, and nanoparticle formation in nanoscale periodic Pt/C multilayer systems containing about 15 at. % Fe have been analyzed by x-ray reflectivity, x-ray standing wave (XSW), transmission electron microscopy, and grazing incidence x-ray diffraction (GIXRD) studies. The multilayer stack with 15 Pt(Fe)/C(Fe) layer pairs (period 4.2 nm) was irradiated with a 2 MeV Au2+ ion beam, which was rastered on the sample to obtain uniformly irradiated strips with fluences (ϕ) from 1×1014 to 1×1015 ions/cm2. Up to a certain threshold ion fluence (ϕt) we have observed mixing between Pt and C atoms. At higher fluences (ϕ>ϕt) demixing effect is pronounced. This phenomenon has been explained in terms of two competitive processes including ballistic and chemically guided atomic movements. As revealed by XSW measurements, ion irradiation causes preferential migration of Fe toward Pt layers from C layers. Consequently Fe concentration in the Pt layers increases with a corresponding decrease in the C layers. The decrease in Fe concentration in the C layers has an exponential dependence on the ion fluence. From the gradual change in shape of the Fe fluorescence yield curve, over the first order Bragg peak region, due to ion irradiation we can infer that Fe atoms migrate from C to Pt layers in the outward direction. This outward migration of Fe has been explained in terms of surface segregation of Fe in Pt under the irradiation condition. Cross-sectional transmission electron microscopy has revealed the gradual change in the microstructure, considerable atomic redistribution, and cluster formation for irradiation at the highest ion fluence (1×1015 ions/cm2), where FePt nanoparticle formation is observed in GIXRD experiments. The results and analysis presented in this work provide an understanding of the evolution of ion-beam-induced ferromagnetism and the increasing coercive field with ion fluence in the Pt(Fe)/C(Fe) multilayer system [B. N. Dev et al., Microelectronic Eng. 83, 1721 (2006)].
Combined micro-Raman/UV-visible/fluorescence spectrometer for high-throughput analysis of microsamples
Authors: Noh Jermim , Suh Yung Doug , Park Yong Ki , Jin Seung Min , Kim Soo Ho , Woo Seong Ihl
Published: July 2007

Combined micro-Raman/UV-visible (vis)/fluorescence spectroscopy system, which can evaluate an integrated array of more than 10 000 microsamples with a minimuma size of 5μm within a few hours, has been developed for the first time. The array of microsamples is positioned on a computer-controlled XY translation microstage with a spatial resolution of 1μm so that the spectra can be mapped with micron precision. Micro-Raman spectrometers have a high spectral resolution of about 2cm−1 over the wave number range of 150–3900cm−1, while UV-vis and fluorescence spectrometers have high spectral resolutions of 0.4 and 0.1nm over the wavelength range of 190–900nm, respectively. In particular, the signal-to-noise ratio of the micro-Raman spectroscopy has been improved by using a holographic Raman grating and a liquid-nitrogen-cooled charge-coupled device detector. The performance of the combined spectroscopy system has been demonstrated by the high-throughput screening of a combinatorial ferroelectric (i.e., BaTixZr1−xO3) library. This system makes possible the structure analysis of various materials including ferroelectrics, catalysts, phosphors, polymers, alloys, and so on for the development of novel materials and the ultrasensitive detection of trace amounts of pharmaceuticals and diagnostic agents.
Linear combinatorial approach to thin film research
Authors: Matias Vladimir , Gibbons Brady J.
Published: July 2007

We describe high-throughput experimentation of film synthesis by use of a linear tape transport system (similar to a web-coating system). Metal tape is fed continuously in a reel-to-reel transport system inside the vacuum deposition chamber. Ion-beam assisted deposition (IBAD) texturing is used to enable the growth of epitaxial films on flexible, polycrystalline metal tapes which further enhances the capability of this research. The tape that is continuously fed can be used as a sample itself, via the use of IBAD-textured templates on the tape, or can be a carrier of other smaller substrates (even nonflexible ones). Characterization of samples is done by means of in situ monitoring as well as ex situ sequential analysis. We utilize in situ reflection high-energy electron diffraction for high-throughput analysis of samples. Epitaxial films are deposited on heated samples by evaporation and by pulsed laser deposition. Here, we explain the techniques and the methodologies developed for this type of combinatorial experimentation and show some examples of the material research completed.
Combinatorial materials research applied to the development of new surface coatings VI: An automated spinning water jet apparatus for the high-throughput characterization of fouling-release marine coatings
Authors: Stafslien Shane J. , Bahr James A. , Daniels Justin W. , Wal Lyndsi Vander , Nevins Jonathan , Smith Jeremy , Schiele Kris , Chisholm Bret
Published: July 2007

Large numbers of coatings can be generated very quickly using a combinatorial high-throughput approach. Rapid screening assays are typically required to adequately evaluate and down select coating candidates to identify promising compositions. An automated, spinning water jet apparatus was developed to rapidly characterize the adhesion strength of marine organisms to coating surfaces. Coating arrays are cast in multiwell plates and subjected to a jet of water of controlled pressure and duration. Array plates are manipulated by a robotic arm to facilitate accurate and repeatable water jet treatments. Jet pressures of 40–688kPa can be generated and precisely maintained by computer control. A five axis robotic arm selects plates from three plate stacking hotels yielding a total of 39 plates or 936 individual coating samples for each experimental run. All robotic instructions, process parameters, and data are stored and controlled by the computer. The large plate handling capacity offered by the robotic system enables the analysis of a wide variety of coatings for “fouling-release” properties. A brief example demonstrating the capability of the automated water jet apparatus to evaluate marine bacterial adhesion to coating surfaces is provided.
Enhancement-mode InP n-channel metal-oxide-semiconductor field-effect transistors with atomic-layer-deposited Al2O3 dielectrics
Authors: Wu Y. Q. , Xuan Y. , Shen T. , Ye P. D. , Cheng Z. , Lochtefeld A.
Published: July 2007

Enhancement-mode (E-mode) n-channel InP metal-oxide-semiconductor field-effect transistors (MOSFETs) with 0.75–40μm gate length fabricated on a semi-insulating substrate with atomic-layer-deposited (ALD) Al2O3 as gate dielectric are demonstrated. The ALD process on III-V compound semiconductors enables the formation of high-quality gate oxides and unpinning of Fermi level on compound semiconductors. A 0.75μm gate length E-mode n-channel MOSFET with an Al2O3 gate oxide thickness of 30nm shows a gate leakage current less than 10μA∕mm at the highest gate bias of 8V, a maximum drain current of 70mA∕mm, and a transconductance of 10mS∕mm. The peak effective mobility is ∼650cm2∕Vs and the interface trap density of Al2O3∕InP is estimated to be ∼(2–3)×1012∕cm2eV.
+Capacitance-voltage characteristics of BiFeO3∕SrTiO3∕GaN heteroepitaxial structures
Authors: Yang S. Y. , Zhan Q. , Yang P. L. , Cruz M. P. , Chu Y. H. , Ramesh R. , Wu Y. R. , Singh J. , Tian W. , Schlom D. G.
Published: July 2007

The authors report the integration of multiferroic BiFeO3 films with the semiconductor GaN using liquid-delivery metal-organic chemical-vapor deposition. Epitaxial BiFeO3 films were deposited via interface control using SrTiO3 buffer/template layers. The growth orientation relationship was found to be (111)[11¯0]BiFeO3‖(111)[11¯0]SrTiO3‖(0001)[112¯0]GaN, with in-plane 180° rotational twins. The C-V characteristics of a Pt∕BiFeO3∕SrTiO3∕GaN capacitor exhibited hysteresis with a memory window of ∼3V at a sweeping voltage of ±30V.
White organic light-emitting devices with a bipolar transport layer between blue fluorescent and orange phosphorescent emitting layers
Authors: Chen Ping , Xie Wenfa , Li Jiang , Guan Tao , Duan Yu , Zhao Yi , Liu Shiyong , Ma Chunsheng , Zhang Liying , Li Bin
Published: July 2007

White organic light-emitting devices based on an orange phosphorescent iridium complex, bis(2-(2-fluorphenyl)-1,3-benzothiozolato-N,C2′) iridium (acetylacetonate) [(F-BT)2Ir(acac)] and blue fluorescent 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl are reported. By introducing a bipolar transport 4,4′N,N′-dicarbazole-biphenyl layer between the fluorescent and the phosphorescent emission layers, additional light emission from (F-BT)2Ir(acac) is observed. The authors attributed it to the elimination of the Dexter energy transfer between the two emitters. Pure white emission with Commission Internationale de I’Eclairage coordinates of (0.33, 0.34) and a maximum luminance of 40960cd∕m2 were obtained. The maximum current efficiency and the color rendering index of the device are 13.4cd∕A and 71, respectively.
Detection of surface brush on biological cells in vitro with atomic force microscopy
Authors: Sokolov Igor , Iyer Swaminathan , Subba-Rao Venkatesh , Gaikwad Ravi M. , Woodworth Craig D.
Published: July 2007

Observation of a brush on the cell surface with the atomic force microscopy (AFM) in vitro is reported. The number of methods to study brushes that coat living cells is limited despite their biological importance. Moreover, it is important to take into account the brush layer when studying cell mechanics. Here the authors present an AFM method to detect the length and grafting density of the brush on viable cells with resolution that considerably surpasses any existing method. The authors demonstrate this method using cultured human cervical epithelial cells, but it can be applied to any type of cell.
Demonstrations of the diffraction and dispersion phenomena of part Fresnel phase zone plates
Authors: Zhang Binzhi , Zhao Daomu , Wang Shaomin
Published: July 2007

The authors report on experimental demonstrations of the diffraction and dispersion phenomena of part Fresnel phase zone plates (FPZPs) by employing a He–Ne laser beam and a white point source. The experimental results have shown that a part square FPZP can behave like a complete circular FPZP, and a part circular FPZP has a focus at 1∕3 f and f with a shift. Some numerical simulations are performed. The simulations and the experiments have shown that the diffraction and dispersion properties of part FPZPs can be well explained by the different diffraction orders.
ΔNp63 regulates thymic development through enhanced expression of FgfR2 and Jag2
Authors: Candi Eleonora , Rufini Alessandro , Terrinoni Alessandro , Giamboi-Miraglia Alessandro , Lena Anna Maria , Mantovani Roberto , Knight Richard , Melino Gerry
Published: July 2007

p63, a homologue of the tumor suppressor p53, is pivotal for epithelial development, because its loss causes severe epithelial dysgenesis, although no information is so far available on the role of p63 in the thymus. We identified the expression of all p63 isoforms in the developing thymus. The p63
−/−
thymi show severe abnormalities in size and cellularity, even though the organ expresses normal levels of keratins 5 and 8, indicating a p63-independent differentiation of thymic epithelial cells (TEC). TEC were sufficiently developed to allow a significant degree of education to produce CD4/CD8 single- and double-positive T cells. To study the selective contribution of transactivation-active p63 (TAp63) and amino-deleted p63 (ΔNp63) isoforms to the function of the TEC, we genetically complemented p63
−/−
mice by crossing p63
+/−
mice with transgenic mice expressing either TAp63α or ΔNp63α under the control of the keratin 5 promoter. Thymic morphology and cellularity were partially restored by complementation with ΔNp63, but not TAp63, one downstream effector being fibroblast growth factor receptor 2-IIIb (FgfR2-IIIb). Indeed, FgfR2-IIIb is regulated directly by p63, via its interaction with apobec-1-binding protein-1, and its knockout shows thymic defects similar to those observed in p63
−/−
thymi. In addition, expression of Jag2, a component of the Notch signaling pathway known to be required for thymic development, was enhanced by p63
in vivo
genetic complementation. Like Jag2
−/−
thymi, p63
−/−
thymi also show reduced γδ cell formation. Therefore, p63, and particularly the ΔNp63 isoform, is essential for thymic development via enhanced expression of FgfR2 and Jag2. The action of ΔNp63 is not due to a direct regulation of TEC differentiation, but it is compatible with maintenance of their “stemness,” the thymic abnormalities resulting from epithelial failure due to loss of stem cells.
Propagation velocity of changes to confinement
Authors: Christiansen J P
Published: July 2007

Transient and non-transient changes to confinement properties of a tokamak equilibrium arise from several different plasma phenomena: a heat pulse triggered by a sawtooth; a cold pulse triggered by impurity injection or a giant ELM; the L ↔ H transitions triggered at the edge can produce a fast response in temperature towards the centre; MHD instabilities like sawtooth collapse, ELM or ‘outer’ mode cause negative-positive changes to the local energy density. Such changes to the confinement properties propagate through the plasma on timescales which are much smaller than the confinement time itself. A model to describe this based on turbulent guiding centre drift motion is developed. The theory for the non-linear model focuses on the propagation of perturbations to the plasma temperature and density. The model predicts a fluctuation-turbulence spectrum which agrees with that observed in experimental fluctuation measurements, apart from the predicted long wavelength part, which is not measured experimentally. A turbulence theory for the guiding centre velocity correlation function is developed in five steps, three of which have often been used in work on turbulence. Step 1 is the random phase approximation. Step 2 is the Markovian approximation. Step 3 is the discrete to continuum approximation. Step 4 is the solution of a prototype non-linear equation for one single harmonic. Step 5 is the solution of a non-linear equation for the entire spectrum of fluctuations using statistical techniques. The solution can be studied in two regimes. The long term or steady state regime has commonly been used in many turbulence theories. On the other hand the short term or ballistic regime predicts that perturbations propagate by advective or wave-like transport relevant to transient changes. The propagation speed is the characteristic guiding centre fluid drift velocity scaled by the ratio between the energy in the fluctuations and the thermal energy. Its magnitude agrees with experimental observations. The validity of the approximations in each of the five steps is discussed, together with how appropriate these are to a tokamak equilibrium with shear.
An algebro-geometric proof of Witten’s conjecture
Authors: Kazarian M. , Lando S.
Published: July 2007

We present a new proof of Witten’s conjecture. The proof is based on the analysis of the relationship between intersection indices on moduli spaces of complex curves and Hurwitz numbers enumerating ramified coverings of the

2
2

-sphere.
Rational points on compactifications of semi-simple groups
Authors: Shalika Joseph , Takloo-Bighash Ramin , Tschinkel Yuri
Published: July 2007

We prove Manin’s conjecture concerning the distribution of rational points of bounded height, and its refinement by Peyre, for wonderful compactifications of semi-simple algebraic groups over number fields. The proof proceeds via the study of the associated height zeta function and its spectral expansion.
Chromatin Remodeling Proteins Interact with Pericentrin to Regulate Centrosome Integrity
Authors: Sillibourne James Edward , Delaval Bénédicte , Redick Sambra , Sinha Manisha , Doxsey Stephen John
Published: July 2007

Pericentrin is an integral centrosomal component that anchors regulatory and structural molecules to centrosomes. In a yeast two-hybrid screen with pericentrin we identified chromodomain helicase DNA-binding protein 4 (CHD4/Mi2β). CHD4 is part of the multiprotein nucleosome remodeling deacetylase (NuRD) complex. We show that many NuRD components interacted with pericentrin by coimmunoprecipitation and that they localized to centrosomes and midbodies. Overexpression of the pericentrin-binding domain of CHD4 or another family member (CHD3) dissociated pericentrin from centrosomes. Depletion of CHD3, but not CHD4, by RNA interference dissociated pericentrin and γ-tubulin from centrosomes. Microtubule nucleation/organization, cell morphology, and nuclear centration were disrupted in CHD3-depleted cells. Spindles were disorganized, the majority showing a prometaphase-like configuration. Time-lapse imaging revealed mitotic failure before chromosome segregation and cytokinesis failure. We conclude that pericentrin forms complexes with CHD3 and CHD4, but a distinct CHD3–pericentrin complex is required for centrosomal anchoring of pericentrin/γ-tubulin and for centrosome integrity.
Quantitative quality-assessment techniques to compare fractionation and depletion methods in SELDI-TOF mass spectrometry experiments
Authors: Harezlak Jaroslaw , Wang Mike , Christiani David , Lin Xihong
Published: July 2007

Motivation: Mass spectrometry (MS), such as the surface-enhanced laser desorption and ionization time-of-flight (SELDI-TOF) MS, provides a potentially promising proteomic technology for biomarker discovery. An important matter for such a technology to be used routinely is its reproducibility. It is of significant interest to develop quantitative measures to evaluate the quality and reliability of different experimental methods.

Results: We compare the quality of SELDI-TOF MS data using unfractionated, fractionated plasma samples and abundant protein depletion methods in terms of the numbers of detected peaks and reliability. Several statistical quality-control and quality-assessment techniques are proposed, including the Graeco–Latin square design for the sample allocation on a Protein chip, the use of the pairwise Pearson correlation coefficient as the similarity measure between the spectra in conjunction with multi-dimensional scaling (MDS) for graphically evaluating similarity of replicates and assessing outlier samples; and the use of the reliability ratio for evaluating reproducibility. Our results show that the number of peaks detected is similar among the three sample preparation technologies, and the use of the Sigma multi-removal kit does not improve peak detection. Fractionation of plasma samples introduces more experimental variability. The peaks detected using the unfractionated plasma samples have the highest reproducibility as determined by the reliability ratio.

Availability: Our algorithm for assessment of SELDI-TOF experiment quality is available at http://www.biostat.harvard.edu/~xlin

Contact:  harezlak@post.harvard.edu

Supplementary information: Supplementary data are available at Bioinformatics online.
A strategy for developing scientific sampling tools for fishery-independent surveys of estuarine fish in New South Wales, Australia
Authors: Rotherham D. , Underwood A. J. , Chapman M. G. , Gray C. A.
Published: July 2007

Rotherham, D., Underwood, A. J., Chapman, M. G., and Gray, C. A. 2007. A strategy for developing scientific sampling tools for fishery-independent surveys of estuarine fish in New South Wales, Australia. – ICES Journal of Marine Science, 64: 1512–1516. The limitations of using fishery-dependent data, i.e. from commercial and recreational fisheries to assess harvested stocks of fish and invertebrates, are well known. Increasingly, fishery-independent surveys are used to validate data from fishery-dependent sources and to provide indices of recruitment and broader ecological information about species not normally retained in fishing operations. Any large-scale, long-term, fishery-independent study must develop sampling gear and designs that are standardized, representative, optimal with respect to the quantity and structure of catch, and replicated over relevant spatial and temporal scales. We present a strategy for achieving appropriate sampling designs. This involves: (i) identifying suitable sampling gears for target species; (ii) testing different configurations of gear and sampling practices to ensure that samples are optimal, representative, and cost efficient; (iii) understanding scales of spatial and temporal variability; and (iv) cost–benefit analyses to optimize replication. Examples of this strategy are illustrated, with brief considerations of the values of pilot research in developing fishery-independent sampling.
The Influence of Grapevine Cultivar and Isolate of Eutypa lata on Wood and Foliar Symptoms
Authors: Sosnowski M. R. , Lardner R. , Wicks T. J. , Scott E. S.
Published: July 2007

Grapevine cultivar (Vitis vinifera) and isolate of Eutypa lata influence wood and foliar symptoms of Eutypa dieback. Foliar symptoms of Eutypa dieback developed within 8 months of inoculating young grapevines (cvs. Grenache, Cabernet Sauvignon, and Merlot) in a shadehouse. Isolates of E. lata from various wine regions in southern Australia varied in their ability to colonize inoculated grapevines and induce wood and foliar symptoms. Grapevine cultivars varied for wood and foliar symptom expression but not for mycelial colonization. However, the severity of foliar symptoms was not related to the rate of spread of the fungus in the grapevine. Furthermore, the staining of wood typically attributed to E. lata did not reflect the presence of the fungus because the fungus was detected up to 80 mm beyond the stain. A field trial with mature grapevines revealed significant differences in the rate of spread of wood staining due to E. lata among eight cultivars, with up to 50 mm/year detected in Cabernet Sauvignon and Shiraz grapevines. In the shadehouse, the maximum growth rate of E. lata was recorded to be 115 mm/year for Grenache rootlings. Information from this study may help to optimize management strategies for maintaining productivity of grapevines with Eutypa dieback, thus reducing the economic impact of the disease.
Influence of Temperature and Humidity on Survival of Penicillium digitatum and Geotrichum citri-aurantii
Authors: Smilanick J. L. , Mansour M. F.
Published: July 2007

Longevity of conidia of Penicillium digitatum (cause of citrus green mold) and arthroconidia of Geotrichum citri-aurantii (cause of sour rot of citrus) was determined under controlled temperature and relative humidity (RH) or ambient summer conditions in central California. Longevity at low RH was longer than at high RH. Hours to kill 99% of the conidia (LT99) of nine P. digitatum isolates were determined at 50°C and 75 or 95% RH. At 75 and 95% RH, the LT99 was 24.9 and 4.9 h, respectively. The LT99 was 30 and 42 days, respectively, for conidia of P. digitatum under ambient conditions at two outdoor locations. The LT99 of arthroconidia of G. citriaurantii from colonies cultured on potato dextrose agar was briefer than that of conidia of P. digitatum. At 45°C and 75 or 95% RH, the LT99 was about 4 and 2 h, respectively, whereas at 50°C, none was viable after 1 h at either humidity. Sanitation is an important practice for managing these diseases. Since there was little or no survival of either fungus after 1 day at 50°C and 75% RH or higher, we conclude that commercial sanitation could employ a similar regime.
Sequential Sampling for Estimation and Classification of the Incidence of Hop Powdery Mildew II: Cone Sampling
Authors: Gent David H. , Turechek William W. , Mahaffee Walter F.
Published: July 2007

Sequential sampling models for estimation and classification of the incidence of powdery mildew (caused by Podosphaera macularis) on hop (Humulus lupulus) cones were developed using parameter estimates of the binary power law derived from the analysis of 221 transect data sets (model construction data set) collected from 41 hop yards sampled in Oregon and Washington from 2000 to 2005. Stop lines, models that determine when sufficient information has been collected to estimate mean disease incidence and stop sampling, for sequential estimation were validated by bootstrap simulation using a subset of 21 model construction data sets and simulated sampling of an additional 13 model construction data sets. Achieved coefficient of variation (C) approached the prespecified C as the estimated disease incidence, [Formula: see text], increased, although achieving a C of 0.1 was not possible for data sets in which [Formula: see text] < 0.03 with the number of sampling units evaluated in this study. The 95% confidence interval of the median difference between [Formula: see text] of each yard (achieved by sequential sampling) and the true p of the original data set included 0 for all 21 data sets evaluated at levels of C of 0.1 and 0.2. For sequential classification, operating characteristic (OC) and average sample number (ASN) curves of the sequential sampling plans obtained by bootstrap analysis and simulated sampling were similar to the OC and ASN values determined by Monte Carlo simulation. Correct decisions of whether disease incidence was above or below prespecified thresholds (pt) were made for 84.6 or 100% of the data sets during simulated sampling when stop lines were determined assuming a binomial or beta-binomial distribution of disease incidence, respectively. However, the higher proportion of correct decisions obtained by assuming a beta-binomial distribution of disease incidence required, on average, sampling 3.9 more plants per sampling round to classify disease incidence compared with the binomial distribution. Use of these sequential sampling plans may aid growers in deciding the order in which to harvest hop yards to minimize the risk of a condition called “cone early maturity” caused by late-season infection of cones by P. macularis. Also, sequential sampling could aid in research efforts, such as efficacy trials, where many hop cones are assessed to determine disease incidence.
Applying Real-Time Quantitative PCR to Fusarium Crown Rot of Wheat
Authors: Hogg A. C. , Johnston R. H. , Dyer A. T.
Published: July 2007

Fusarium crown rot (FCR) of wheat is a persistent problem that causes significant losses worldwide. In Montana, FCR is caused primarily by Fusarium culmorum and F. pseudograminearum. Recently, a real-time quantitative PCR (QPCR) assay was developed for FCR using primers and probes specific for a segment of the trichodiene synthase (tri5) gene. The purpose of this study was to determine the utility of QPCR for accessing FCR severity on wheat in field experiments. In 2004 and 2005, plots of spring and durum wheat were inoculated with varying levels of F. pseudograminearum oat inoculum and grown under rain-fed conditions. Two weeks prior to harvest, plants were collected from the plots and assessed for FCR severity and analyzed by QPCR for Fusarium DNA quantities. Disease severity scores (DSS) and Fusarium DNA quantities were positively correlated with each other for all three cultivars in 2004 but for only the durum cultivar in 2005 (P < 0.05). In 2004, grain yields for both spring wheat cultivars were negatively correlated with Fusarium DNA quantities (P > 0.05). When DSS and Fusarium DNA quantities negatively correlated with yield, both measurements were comparable in predicting yield reduction (R = –0.64 and –0.77, respectively). Results indicate that this QPCR assay is effective in measuring FCR severity in wheat.
Temperature-Sensitive Wheat streak mosaic virus Resistance Identified in KS03HW12 Wheat
Authors: Seifers D. L. , Martin T. J. , Harvey T. L. , Haber S.
Published: July 2007

Wheat streak mosaic virus (WSMV) infection reduces seed yield and quality in wheat. These losses can be alleviated significantly by exploiting genetic host plant resistance. A new source of temperature-sensitive resistance to WSMV, KS03HW12, and its parental lines (KS97HW29/ KS97HW131//KS96HW100-5) were evaluated in both greenhouse and field conditions. Parental wheat lines were exposed to WSMV pressure under different temperatures in growth chambers to determine the stability of the resistance, and 2 years of field yield trials were conducted to confirm effectiveness. To determine the effectiveness of its resistance against a spectrum of isolates, KS03HW12 was tested against six different WSMV isolates of different geographic origins. Among the three pedigree parents, only one, KS97HW29, was resistant. The parental lines of KS97HW29 are not available for testing; therefore, the presumed origin of the resistance could not be further confirmed. None of the six tested WSMV isolates systemically infected KS03HW12 at 18°C. Yield of KS03HW12 in field tests was not different from healthy controls. Thus, the elite winter wheat KS03HW12 appears to be a stable and effective source of temperature-sensitive resistance to WSMV and should be useful for wheat breeding programs.
Survival of Phytophthora ramorum in Recirculating Irrigation Water and Subsequent Infection of Rhododendron and Viburnum
Authors: Werres S. , Wagner S. , Brand T. , Kaminski K. , Seipp D.
Published: July 2007

Phytophthora ramorum was studied in an open air simulation system with nine separate container stands each connected to its own water collection system. The water in these reservoirs was inoculated with P. ramorum and then used for overhead irrigation over the course of the season to study the spread of the pathogen and development of P. ramorum blight in Rhododendron and Viburnum spp. P. ramorum could infect plants through the use of contaminated irrigation water, with the maximum amount of infection of Rhododendron spp. less than 19%. In the 2 years of the study, symptom onset occurred 8 and 16 days, respectively, after water was first inoculated. The disease rate proportion of infected plants developing symptoms varied with year and season. In both years, the pathogen was detected in the water reservoirs over the course of the growing season.
First Report of Potato spindle tuber viroid in Tomato in Belgium
Authors: Verhoeven J. Th. J. , Jansen C. C. C. , Roenhorst J. W. , Steyer S. , Michelante D.
Published: July 2007

During August of 2006, a sample of a tomato plant (Solanum lycopersicum, formerly Lycopersicum esculentum) from a greenhouse in Belgium was received for diagnosis. The plant showed severe growth reduction and the young leaves were chlorotic and distorted. In the greenhouse, the disease had been spreading slowly along the row. These observations suggested the presence of a viroid infection, and reverse transcriptase (RT)-PCR with two sets of universal pospiviroid primers (Pospi1-RE/FW and Vid-FW/RE; 3) yielded amplicons of the expected size (approximately 196 and 360 bp). Sequence analysis of the larger PCR product revealed that the genome was 358 nt and 100% identical to two isolates of Potato spindle tuber viroid (PSTVd) previously submitted to the NCBI GenBank (Accession Nos. AJ583449 from the United Kingdom and AY962324 from Australia). A pathogen associated with the symptomatic tomato plants was therefore identified as PSTVd. Tracing the origin of the infection revealed the following information: during November of 2005, 8-day-old tomato seedlings raised from seed by a Dutch nursery were transferred to a small part of the greenhouse of the Belgian grower; 7 to 8 weeks later, the plants were transplanted to their final destination; during May of 2006, the grower first observed growth reduction in a single plant; several weeks later, similar symptoms were observed in two more plants in the same row close to the first symptomatic plant; and by September, there were approximately 20 symptomatic tomato plants, all located in two adjacent rows. The viroid outbreak was fully eradicated by destroying all tomato plants in the affected rows as well as in two adjacent rows at both sides. The absence of further infections was confirmed by testing approximately 1,200 tomato plants in pooled samples for PSTVd by RT-PCR (2) and real-time RT-PCR (1). The origin and the method of introduction and spread of the viroid remain unclear.

References: (1) N. Boonham et al. J. Virol. Methods 116:139, 2004. (2) R. A. Mumford et al. Plant Pathol. 53:242, 2004. (3) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 110:823, 2004.
First Report of Phytophthora ramorum and P. inflata in Ornamental Rhododendrons in Finland
Authors: Lilja A. , Rytkönen A. , Kokkola M. , Parikka P. , Hantula J.
Published: July 2007

Phytophthora ramorum was found for the first time in Finland during the spring of 2004 on marketed plants of Rhododendron spp. originating in other EU member states. During August of 2004, the pathogen was also found in one Finnish nursery on German Rhododendron catawbiense plants and several Finnish Rhododendron spp. cultivars. P. ramorum was detected by species-specific PCR and isolated (1). It was first characterized by an abundant production of chlamydospores on PARP and V8 agar, absence of oogonia and antheridia, and elongate, ellipsoid, deciduous, semipapillate sporangia produced in soil extract water (3). A partial sequence of the β-tubulin gene was identical to that of P. ramorum deposited in GenBank. Despite strict regulations governing the movement of plants, the pathogen has been found every year since 2004 on materials transported to Finland from other EU countries. A total of 586 samples were taken from symptomatic plants of several susceptible species from 2004 to 2006. P. ramorum was detected in 51 rhododendron samples and the number of the outbreak sites was 28. In domestic plant production, P. ramorum was found in only one nursery. The infected plants in this nursery were destroyed in 2005 according to the EU regulation 2004/426/EG. During the 2006 growing season, 84 samples from trace-forward inspections and reinspections of the nursery were tested and P. ramorum was not detected in any of the samples. In 2005, surveys for P. ramorum on Finnish Rhododendron spp. cultivars with necrotic lesions on leaves and blackened tips yielded, in addition to P. ramorum, another Phytophthora sp. On V8 agar, this homothallic species showed a stellate growth pattern with sparse aerial mycelium. Oogonia had both paragynous and amphigynous antheridia, and sporangia produced in soil extract water were ellipsoid in shape and semipapillate. A 763-bp segment of the β-tubulin gene was sequenced and was identical to the β-tubulin sequence of P. inflata strain IMI342898 (GenBank), which was isolated in 1990 from Syringa sp. in the UK. It is likely that this P. inflata strain has been spreading in Europe with the ornamental plant trade. To fulfill Koch's postulates, rhododenrdon plants were inoculated (2) with P. inflata or P. ramorum, typical symptoms observed, and the pathogens were reisolated from inoculated plants. Both Phytophthora species also caused necrotic lesions on Alnus glutinosa, A. incana, and Betula pendula. Pinus sylvestris was resistant to both Phytophthora spp., whereas Picea abies was susceptible to P. inflata but not P. ramorum.

References: (1) EPPO Bull. 36:145, 2006. (2) E. Hansen et al. Plant Dis. 89:63, 2005. (3) S. Werres et al. Mycol. Res. 105:1155, 2001.
Occurrence of Tomato yellow leaf curl virus in Tomato in Martinique, Lesser Antilles
Authors: Urbino C. , Dalmon A.
Published: July 2007

During April of 2002, symptoms of stunting and chlorotic curled leaves of reduced size, similar to those caused by Tomato yellow leaf curl virus (TYLCV), were observed for the first time in commercial tomato (Solanum lycopersicum) in the northwest region of Martinique. Six months later, many tomato fields had more than 80% of plants expressing these symptoms and yield was drastically reduced. Samples from two symptomatic plants were collected and analyzed by PCR. Primers PC1 (5′-TGACTATGTCGAAGCGACCAGG-3′) and PC2 (5′-CGACATTACAGCCTCAGACTGG-3′) were used to amplify a 950-bp fragment within the coat protein gene (CP) of TYLCV species (1). Primer pair MP16-MP82 (2) amplified a 550-bp fragment from the conserved nonanucleotide sequence (TAATATTAC) to the 5′ end of the CP gene. Products of expected sizes were obtained with both pairs of primers from symptomatic samples but not from uninfected ones. The two overlapping PCR products were cloned into a pGEM-T Easy Vector (Promega, Madison, WI) and sequenced. A BLAST analysis was conducted with begomovirus sequences available in the GenBank database at the NCBI, and DNAMAN software (Lynnon Corporation, Quebec, Canada) was used for further comparisons. The 1275-bp sequence (GenBank Accession No. EF490995) shared 99% nucleotide identity with the partial sequences of TYLCV from Antigua and Barbuda (GenBank Accession No. EF028240), Saint Kitts and Nevis (GenBank Accession No. EF028239), and the two overlapping sequences from Guadeloupe (GenBank Accessions No. AY319645 and AY319646). It was at least 98% identical to TYLCV isolates from Florida (GenBank Accession No AY530931), Dominican Republic (GenBank Accession No. AF024715), and Cuba (GenBank Accession No. AJ223505). These results confirm the introduction of TYLCV into Martinique, possibly from a nearby Caribbean country, and reveal its southward spread in the Lesser Antilles. The nearness of the islands in the Lesser Antilles (20 to 100 km distant) probably permitted the rapid spread of TYLCV through the movement of plant material or wind transport of viruliferous whiteflies from one island to the next. Monitoring the spread of TYLCV in this Caribbean archipelago is important for regional virus management and in forecasting the spread of TYLCV to nearby countries in South America.

References: (1) Y. Martinez et al. Rev. Prot. Veg. 18:168, 2003. (2) P. Umaharan et al. Phytopathology 88:1262, 1998.
First Report of Cylindrocarpon liriodendri Causing Black Foot Disease of Grapevine in California
Authors: Petit E. , Gubler W. D.
Published: July 2007

Black foot disease is a recently identified but worsening problem in vineyards worldwide (2). Roots of symptomatic grapevines show black, sunken, necrotic lesions (2). In cross section, the base of the trunk appears necrotic and xylem vessels are plugged with black inclusions and tyloses (2). Aboveground, leaves of infected vines appear to be scorched, and the entire vine becomes stunted and frequently dies (2). In California, we previously identified two Cylindrocarpon species as causal agents of this disease: C. macrodidymum and C. destructans (2). In earlier molecular phylogenetic studies, tremendous variation in C. destructans from diverse hosts was found, indicating that this species might encompass more than one species (2). On the basis of analysis of sequences of three independent DNA regions, we concluded that the group of C. destructans isolated from grapevines in France, South Africa, and California have nearly identical sequences and form a well-supported sister clade divergent from the clade containing C. destructans found in numerous hosts (2). Further studies compared DNA sequences of C. destructans causing black foot in France, Portugal, and South Africa with an ex-type strain of C. liriodendri isolated from tulip poplar (Liriodendron tulipifera) (1). Because these species had identical sequences, C. destructans causing black foot in France, Portugal, and South Africa was renamed C. liriodendri (1). The objective of the current study was to clarify the taxonomy of C. destructans causing black foot in California. We compared C. liriodendri isolate CBS112602 from South Africa (1) with three C. destructans isolates (USME116, USST148, and USSO150) from California (2). We analyzed four sequences on three genomic regions: the internal transcribed spacer of ribosomal DNA, partial sequences of the beta tubulin gene, and the mitochondrial small subunit ribosomal DNA. We used sequences from the South African C. liriodendri isolate CBS112602 (AY997566, AY997586, AY997581, and AY997532) and sequences from Californian isolates of C. destructans (AY997568, AY997588, AY997534, AY997583, AY997569, AY997601, AY997547, AY997584, AY997570, AY997598, AY997544, and AY997585) previously deposited in GenBank (2). Sequences were aligned using Clustal X 1.8 (3). On the basis of visual inspection of each DNA region alignment, the South African C. liriodendri isolate was identical to Californian isolates of C. destructans. Thus, Californian isolates of C. destructans causing black foot (2) are renamed C. liriodendri. To our knowledge, this is the first report of C. liriodendri causing black foot disease of grapevine in California.

References: (1) F. Halleen et al. Stud. Mycol. 55:227, 2006. (2) E. Petit and W. D. Gubler. Plant Dis. 89:1051, 2005. (3) J. D. Thompson et al. Nucleic Acids Res. 25:4876, 1997.
Discarding practices in a Mediterranean small‐scale fishing fleet (Patraikos Gulf, Greece)
Authors: Tzanatos E. , Somarakis S. , Tserpes G. , Koutsikopoulos C.
Published: July 2007

Abstract  Discarding practices from 110 fishing operations in a Mediterranean small‐scale fishing fleet (Patraikos Gulf, western Greece) from August 2004 to July 2005 were analysed. On average, 1 kg of fish was discarded per fishing operation (10% of the catch). The reasons for discarding were: low commercial value (78% of discards), damage at sea before retrieval of the gear (5%), and bad handling on‐board (17%). More than half of discards belonged to Spicara flexuosa (L.), Lepidopus caudatus (Euphrasen), Sardinella aurita Valenciennes and Merluccius merluccius (L.). The bulk of discards of each species were associated with a single fishing method (metier). A Generalized Linear Model (Delta‐X – error‐model) indicated that, when discards were present, significant differences existed in the discard ratio among different métier groups (groups comprising métiers with similar characteristics). Longlines and trammel nets with small mesh‐sizes had the highest discard ratios. Discarding practices for the species Diplodus annularis (L.), S. aurita, Squilla mantis (L.), S. flexuosa and Scorpaena scrofa (L.) did not follow a consistent pattern (these species were either fully discarded or fully retained during a fishing operation). The decision seemed to be dependent on market demands rather than fish size. Significant correlation was found between discarded and catch weight, but the presence of many outliers indicated deviance from a case where discards are high when there is an abundant catch. The findings of the study imply that monitoring and management should be carried out preferably on the métier level. Discards could be reduced by technical measures, controlling effort regulations and by improving working conditions on‐board fishing vessels.