bluuebunny/crossref_metadata_2025 huggingface dataset:
High-resolution capacitive load-displacement transducer and its application in nanoindentation and adhesion force measurements
Authors: Yu Ning , Bonin Wayne A. , Polycarpou Andreas A.
Published: March 2005

A high-resolution load-displacement transducer is developed based on a capacitive-plate configuration. The transducer applies a force via electrostatic actuation and senses displacement via monitoring the change in capacitance. The external applied load on the transducer is measured as the difference between the electrostatic force and the spring force induced by the displacement. Compared to a conventional design, the present improved transducer offers not only enhanced reliability, but also much less moving mass and better electronic circuitry, thus improved practical load and displacement resolutions. It is found that the present transducer has a rms load resolution of 3nN when tested in a reduced vibration environment, and 10–20nN when directly attached on a multimode AFM for performing realistic experiments. Similarly, the displacement resolution of the present transducer is 0.05 and 0.12nm under reduced vibration and attached on the AFM, respectively. Subsequently, the new transducer is integrated with a multimode AFM to perform in situ nanoindentation and adhesion (pull-off) force measurements to illustrate the improved capability of the transducer. The high resolution of the present transducer enables the observations of clear loading–unloading curves in the sub-10-nm nanoindentation and “jump-on” phenomena in pull-off force measurements, both of which were previously masked by noise when using a commercially available similar transducer.
Glycine-ice nanolayers: Morphology and surface energetics
Authors: Tzvetkov G. , Ramsey M. G. , Netzer F. P.
Published: March 2005

Ultrathin glycine-ice films (nanolayers) have been prepared in ultrahigh vacuum by condensation of H2O and glycine at 110K and 150K on single crystalline Al2O3 surfaces and have been investigated by temperature programed thermal desorption, x-ray photoelectron spectroscopy, and work function measurements. Various layer architectures have been considered, including glycine-on-ice, ice-on-glycine, and mixed glycine-ice nanolayers. Low coverages of adsorbed glycine molecules on amorphous ice surfaces suppress the amorphous-to-crystalline phase transition in the temperature range 140–160K in near-surface regions and consequently lead to a lower desorption temperature of H2O molecules than from pure ice layers. Thicker glycine overlayers on ice provide a kinetic restriction to H2O desorption from the underlying ice layers until the glycine molecules become mobile and develop pathways for water desorption at higher temperature (>170K). Ice overlayers do not wet glycine film surfaces, but the glycine molecules on ice are sufficiently immobile at 110K, so that continuous glycine overlayers form. In mixed glycine-ice nanolayers the glycine phase displays hydrophobic behavior and a phase separation takes place, with the accumulation of glycine near the surfaces of the films.
Dielectric properties of A- and B-site doped BaTiO3(II):La- and Ga-doped solid solutions
Authors: Gulwade D. D. , Bobade S. M. , Kulkarni A. R. , Gopalan P.
Published: March 2005

Extremely small amounts of codoping La and Ga on the A and B sites of BaTiO3, respectively, resulting in a solid solution of the type Ba1−3xLa2xGa4xTi1−3xO3, have been investigated. The compounds have been prepared by conventional solid-state reaction. The x-ray diffraction (XRD) shows the presence of the tetragonal (P4∕mmm) phase only. The XRD data have been analyzed using the FULLPROF Rietveld refinement package. The compositions have been characterized by dielectric spectroscopy between room temperature and 200°C. The resulting compounds (0⩽x⩽0.008) exhibit a remarkable decrease in Curie temperature as well as a significant enhancement in the dielectric constant.
In situ growth of nanowire on the tip of a carbon nanotube under strong electric field
Authors: Wang Y. G. , Li Q. H. , Wang T. H. , Lin X. W. , Dravid V. P. , Zhou S. X.
Published: March 2005

We present experimental evidence of in situ growth of carbon nanowires on the tip of a carbon nanotube under an applied voltage of 150 V. The grown nanowires with the well-defined geometry and diameter less than ten nanometers are structurally amorphous in nature and result in the solid carbon nanotube-nanowire junction with minimum junction size. The as-generated carbon nanotube-nanowire junction with a distinctive morphology clearly shows evidence of the bonding between the carbon atoms at the tip of carbon tube. The carbon nanotube could be used as a template for in situ growth of the carbonate nanowires under a strong electric field. The measured current-voltage (I-V) characteristic of the nanotube-nanowire contact shows a nonlinear relation between the current and applied bias voltage due to the saturated sp3 bonds formed at the junction. The detected I-V behavior suggests the formation of the metal∕insulator∕metal structure at the nanotube-nanowire junction.
The molecular approach to heterogeneous nucleation
Authors: Zapadinsky Evgeni , Lauri Antti , Kulmala Markku
Published: March 2005

A molecular approach to heterogeneous nucleation has been developed. The expressions for the equilibrium cluster distribution, the reversible work of the cluster formation, and the nucleation rate have been derived. Two separate statements for the work of formation were formulated. If the equilibrium cluster distribution is normalized on the monomer concentration near the substrate surface, the reversible work of formation is expressed by ΔGhetI=(Fnhet−Fnhom)−(F1het−F1hom)+ΔGhom where Fnhet and Fnhom are the Helmholtz free energies of a cluster interacting with a substrate and a cluster not interacting with the substrate, respectively. If the equilibrium cluster distribution is normalized on the monomer concentration far from the substrate surface, the work of cluster formation is given by ΔGhetII=(Fnhet−Fnhom)+ΔGhom. The former expression corresponds to the approach of the classical heterogeneous nucleation theory. The cluster partition function appears to be dependent on the location of a virtual plane, which separates the volume, where the interaction of the clusters with the substrate is effective from the one where interaction is negligible. Our Monte Carlo simulations have shown that the dependence is rather weak and thus the location of the plane is not very important. According to the simulations the variation of the plane position in the range from 20 to 50 Å does not lead to a considerable change of the heterogeneous nucleation rate.
Calculation of the magnetic stray field of a uniaxial magnetic domain
Authors: Engel-Herbert R. , Hesjedal T.
Published: March 2005

We present an analytic solution for the magnetic field of a bar-shaped permanent magnet. Assuming a constant magnetization, we derive expressions for the stray field in three dimensions. The analytic solutions can be readily applied to field calculation problems for magnetic force microscopy simulations without the need for finite element methods.
Scanning tunneling microscope-based thermochemical hole burning on a series of charge transfer complexes
Authors: Yu Xuechun , Peng Hailin , Ran Chunbo , Sun Lei , Zhang Ran , Liu Zhongfan
Published: March 2005

A thermochemical hole burning effect was observed on a series of 7, 7, 8, 8-tetra cyanoquinodimethane charge transfer complexes when applying a suitable voltage pulse using scanning tunneling microscope, which is attributed to the localized thermochemical decomposition of the complex induced by the current heating effect. The decomposition reaction evolves the low boiling point decomposition components of the charge transfer complex, leaving a nanometer-sized hole on the crystal surface. This effect demonstrates the possibility of creating a ultrahigh density thermochemical hole burning memory, in which information bit is recorded as a hole.
Effective negative refraction index in periodic metal–ferrite–metal film composite
Authors: Wu R. X.
Published: March 2005

We analyze the refraction index of periodic metal–ferrite–metal film composite in microwave frequencies by the transfer matrix method. We show that the composite can be equal to a homogeneous material with a negative effective refraction index in certain frequencies. Two negative index states have been found in the composite. One has the negative effective permittivity and negative effective permeability simultaneously, and the other only has negative effective permeability. The transition between them can be controlled by the values of electron damping coefficient in the metal films.
Interactions of B dopant atoms and Si interstitials with SiO2 films during annealing for ultra-shallow junction formation
Authors: Kohli P. , Jain A. , Chakravarthi S. , Bu H. , Dunham S. T. , Banerjee S.
Published: March 2005

In this work we present an investigation of the effect of oxide thickness on annealed B diffusion profiles. Experiments were specifically designed to determine the effect of varying oxide thickness on the B diffusion profile after annealing. Boron was implanted through a 50Å screen oxide. Implant oxide was etched to varying degrees on different samples resulting in screen oxide thickness from 0 to 50Å. On samples where the screen oxide was completely etched away, cap oxide was deposited with thickness varying from 0 to 50Å. The implanted wafers were then spike annealed at 1050°C. We found that the thicker the oxide during annealing, the deeper the B diffusion profile. A model of the Si–SiO2 system based on the interactions of B dopant atoms and silicon interstitials with SiO2 films is proposed to explain the experimental observations. The model takes into account the segregation of Si interstitials at the Si∕SiO2 interface and the diffusion of that Si in the oxide.
Electronic structure and x-ray-absorption near-edge structure of amorphous Zr-oxide and Hf-oxide thin films: A first-principles study
Authors: Kim SungKwan , Kim Yangsoo , Hong Jongin , Tanaka Isao , No Kwangsoo
Published: March 2005

First-principles calculations were performed on the electronic structure and x-ray-absorption near-edge structure (XANES) of amorphous Zr-oxide and Hf-oxide thin films. Using the discrete variational X-α method, the authors simulated the films with (Zr4O17)−18 and (Hf4O18)−20 clusters. The O–Zr and O–Hf bonds were found to have different characteristics along the bond orientation. By comparing the experimental and calculated XANES, we analyze the absorption mechanism of amorphous Zr-oxide and Hf-oxide thin films for energies up to 10eV above the OK edge.
Ternary rare-earth metal oxide high-k layers on silicon oxide
Authors: Zhao C. , Witters T. , Brijs B. , Bender H. , Richard O. , Caymax M. , Heeg T. , Schubert J. , Afanas’ev V. V. , Stesmans A. , Schlom D. G.
Published: March 2005

Ternary oxides, GdScO3, DyScO3, and LaScO3, deposited by pulsed laser deposition using ceramics targets of stoichiometric composition, were studied as alternative high-k gate dielectrics on (100) Si. Their physical characterization was done using Rutherford backscattering, spectroscopic ellipsometry, x-ray diffraction, and transmission electron microscopy on blanket layers deposited on (100) Si, and electrical characterization on capacitors. It is found that DyScO3 and GdScO3 preserve their amorphous phases up to 1000°C. Other encouraging properties for high k applications were demonstrated, including k-value ∼22, almost no hysteresis or frequency dispersion in C–V curves, and leakage current reduction comparable to that of HfO2 of the same equivalent oxide thickness.
Spatial separation of vacancy and interstitial defects formed in Si by oxygen-ion irradiation at elevated temperature
Authors: Danilov I. , Boudinov H. , de Souza J. P. , Drozdov Yu. N.
Published: March 2005

A study of damage depth distribution in Si by elevated temperature O+-ion implantation was performed using three structures: (i) bulk Si, (ii) Si∕SiO2∕bulk Si, and (iii) SiO2∕bulk Si. The samples were implanted at 250 °C with a dose of 5×1016cm−2 at an energy of 185 keV. By this approach, the damage depth profile distributes along the SiO2 and Si layers in a different manner according to the sample structure. A comparative analysis of the high-resolution x-ray diffraction spectra taken from the implanted samples permitted us to infer on the spatial separation between vacancy and interstitial-rich layers, which are associated with the presence of negative and positive strained layers, respectively.
Resonance-tunneling-assisted emission enhancement in green light-emitting diodes with nanocraters formed in InGaN∕GaN quantum-well active layers
Authors: Song Jae Ho , Song G. Hugh , Lee Jhang W. , Ok Young-Woo , Seong Tae-Yeon , Laboutin Oleg , Deluca Paul , Choi H. K.
Published: March 2005

Data are presented on the resonant tunneling-related abrupt redshift observed in the temperature-dependent electroluminescence spectra of high-brightness InGaN∕GaN multi-quantum-well green light-emitting diodes (LEDs). It is found that the redshift arises mostly between 120 and 150K, and brighter LEDs yield larger redshifts. These results are well explained by the proposed nanocrater model which comprises a Ga-rich quantum barrier surrounding the In-rich quantum-dot-like localized state. Intensity analysis manifests that the resonant tunneling from the quantum-well to the nanocrater-shaped localized states induces such an abrupt energy shift and enhances the room-temperature emission.
10
GHz
passively mode-locked external-cavity semiconductor laser with 1.4W average output power
Authors: Aschwanden A. , Lorenser D. , Unold H. J. , Paschotta R. , Gini E. , Keller U.
Published: March 2005

We present a 10GHz passively mode-locked vertical external-cavity surface-emitting semiconductor laser (VECSEL) with 1.4W average output power in 6.1ps pulses. The output features a very good pulse quality with a time–bandwidth product of 0.42 in a nearly diffraction-limited beam. This demonstrates that passively mode-locked VECSELs are suitable for generating high powers in high-repetition-rate pulse trains.
Optical properties of transparent Li2O–Ga2O3–SiO2 glass-ceramics embedding Ni-doped nanocrystals
Authors: Suzuki Takenobu , Murugan Ganapathy Senthil , Ohishi Yasutake
Published: March 2005

Transparent Li2O–Ga2O3–SiO2 (LGS) glass-ceramics embedding Ni:LiGa5O8 nanocrystals were fabricated. An intense emission centered around 1300nm with the width of more than 300nm was observed by 976nm photoexcitation of the glass-ceramics. The lifetime was more than 900μs at 5K and 500μs at 300K. The emission could be attributed to the T2g3(F3)→A2g3(F3) transition of Ni2+ in distorted octahedral sites in LiGa5O8. The product of stimulated emission cross section and lifetime for the emission was about 3.7×10−24cm2s and was a sufficiently practical value.
Pinch off of nanopipes under electron irradiation in GaN
Authors: Pailloux F. , Colin J. , Barbot J. F. , Grilhé J.
Published: March 2005

Long hollow nanopipes in epitaxial GaN thin films have been found to evolve under electron irradiation into the so-called bamboolike structure. The transition from the single nanopipe into a chain of pinholes is described in terms of morphological instability driven by the differences in the surface energy of crystallographic planes.
Carrier trapping and efficient recombination of electrophosphorescent device with stepwise doping profile
Authors: Chin Byung Doo , Suh Min Chul , Kim Mu-Hyun , Lee Seong Taek , Kim Hye Dong , Chung Ho Kyoon
Published: March 2005

We have presented a physical concept for enhancing efficiency and lifetime of doped electrophosphorescent organic light-emitting devices. In order to provide a control parameter for higher device performance, a stepwise doping concentration profile at the emission layer was prepared. A more than 30% improvement of power efficiency was obtained for green electrophosphorescent device with a higher doping ratio at the emission layer-hole transport layer interface. We explained the carrier trapping and transport mechanism with direct recombination of an exciton in an iridium-based dopant system. When compared to green device, phosphorescent red devices showed a more significant charge trapping effect at low doping concentration, which is responsible for shifting the recombination zone far from the emission layer-hole transport layer interface. Therefore, charge trapping by doping control in an emission layer could be utilized for a charge-balancing technique for the confinement of a triplet exciton.
Surface-sensitive macrobolometers for the identification of external charged particles
Authors: Foggetta Luca , Giuliani Andrea , Nones Claudia , Pedretti Marisa , Sangiorgio Samuele
Published: March 2005

We report the performance of two prototype TeO2 macrobolometers, operated at ∼25mK, able to identify events due to energy deposited at the detector surface. This capability is obtained by thermally coupling thin Ge active layers to the main energy absorber of the bolometer, and is demonstrated by irradiating the detectors with α particles. The temperature variations of the main absorber and of the active layer are measured independently with doped Ge thermistors. These results show clearly that an intrinsic limitation of monolithic low temperature calorimeters, e.g., the impossibility to give information about event position, can be efficiently overcome using composite structures.
Single-metalloprotein wet biotransistor
Authors: Alessandrini Andrea , Salerno Marco , Frabboni Stefano , Facci Paolo
Published: March 2005

Metalloproteins are redox molecules naturally shuttling electrons with high efficiency between molecular partners. As such, they are candidates of choice for bioelectronics. In this work, we have used bacterial metalloprotein azurin, hosted in a nanometer gap between two electrically biased gold electrodes, to demonstrate an electrochemically gated single-molecule transistor operating in an aqueous environment. Gold-chemisorbed azurin shows peaks in tunneling current upon changing electrode potential and a related variation in tunneling barrier transparency which can be exploited to switch an electron current through it. These results suggest the wet approach to molecular electronics as a viable method for exploiting electron transfer of highly specialized biomolecules.
Low-voltage pentacene thin-film transistors with Ta2O5 gate insulators and their reversible light-induced threshold voltage shift
Authors: Liang Yan , Dong Guifang , Hu Yan , Wang Liduo , Qiu Yong
Published: March 2005

We have fabricated pentacene thin-film transistors using Ta2O5 films prepared by magnetron reactive sputtering as gate insulators. These transistors exhibit good electrical characteristics at an operating voltage as low as 5 V, with a field-effect mobility of 0.32cm2∕Vs, an on∕off ratio of 104, and a subthreshold slope of 0.5V∕decade. We have also investigated the optical properties of these transistors and observed a reversible light-induced threshold voltage shift. Under illumination, the threshold voltage shifts towards the positive direction while the field-effect mobility and on∕off ratio remain almost unchanged. In the dark, however, the threshold voltage can slowly be restored to its original state. At a gate voltage of −5V, the transistors show a broadband responsivity of 3.7A∕W after illumination at 60μW∕cm2 for 10 min.
Electrical conduction transition and largely reduced leakage current in aluminum-doped barium strontium titanate thin films heteroepitaxially grown on Ir∕MgO∕Si(100)
Authors: Chen T. L. , Li X. M. , Wu W. B. , Yu W. D. , Gao X. D. , Zhang X.
Published: March 2005

Ba 0.6 Sr 0.4 Ti 1 − x Al x O 3 (BSTA, x=0, 3 at. %, 6 at. %) thin films have been prepared on Ir∕MgO-buffered silicon substrates by pulsed-laser deposition. All-epitaxial growth of BSTA∕Ir∕MgO∕Si heterostructures has been evidenced by x-ray diffraction and reflection high-energy electron diffraction. A large reduction in the leakage current density of BSTA thin films was observed by aluminum doping. For 3 at. % Al-doped BSTA thin films, the dominant conduction mechanism shows space-charge-limited current behavior at a low electric field, where the trap-filled limit field is determined as ETFL=10KV∕cm, while at a high electric field the Poole–Frenkel emission is operative. In contrast, the conduction mechanism for 6 at. % Al-doped BSTA thin film is dominated by field-enhanced Schottky emission.
Fabrication of CdS∕Si nanocable heterostructures by one-step thermal evaporation
Authors: Fu X. L. , Ma Y. J. , Li P. G. , Chen L. M. , Tang W. H. , Wang X. , Li L. H.
Published: March 2005

Coaxial CdS∕Si nanocable heterostructures with a length of hundreds of micrometers and an average diameter of 100nm were fabricated via one-step thermal evaporation of CdS powder under experimentally controlled conditions. The CdS cores have a hexagonal crystal structure. The Si sheaths are amorphous and can be directly grown on the CdS surfaces from the silicon substrate via a vapor-liquid-solid mechanism without an extra Si source. The photoluminescence of the nanocables presents two emission bands, around 510 and 590nm. This simple method may be applied to other Si-sheathed heterostructures, which can be used in nanodevices with various functions.
Nanomechanical hydrogen sensing
Authors: Huang X. M. H. , Manolidis M. , Jun Seong Chan , Hone J.
Published: March 2005

A nanomechanical beam resonator is used as a sensitive, specific hydrogen sensor. The beam is fabricated from AuPd alloy and tested by magnetomotive transduction at room temperature. The fundamental resonance frequency decreases significantly and reversibly at hydrogen pressures above 10−5Torr, whereas the frequency shifts observed for other gases are significantly smaller. The large frequency shift is likely due to the formation of interstitial hydrogen in the metal alloy lattice, which relieves the built-in tensile stress in the resonator beam. The uptake of hydrogen as measured by frequency shift is consistent with previous studies.
Pastoralism in tropical rangelands: seizing the opportunity to change
Authors: Ash Andrew , Smith Mark Stafford
Published: March 2005

The pastoral industry in northern Australia has been relatively stable over the past 100 years and has persisted despite a variable climate, uncertain markets and variable prices. However, change is occurring at a rapid pace and to stay economically viable and environmentally sustainable in the future the pastoral industry must deal proactively with the continuous cost-price squeeze and growing environmental awareness in society at large We contend that controlling these factors involves targeted intensification of effort to minimise costs, maximise opportunities to improve productivity, and demonstrated environmental standards to increase product value, building on the most effective use of new communications technologies, a better integration with the values of other inhabitants of the region, and processes from continuous learning. Pastoralists will also need to be ever vigilant about external drivers of change, over which they have no control, and be prepared to adapt early to cope with these external influences.
Germinable soil seedbanks in native pastures near Crows Nest, south-east Queensland
Authors: McIvor J. G. , Saeli I. , Hodgkinson J. J. , Shelton H. M.
Published: March 2005

The soil seedbanks in three patch types (tall grassland, short sward and lawn) were measured in native pastures near Crows Nest, south-east Queensland in two experiments. In the first experiment, seedbanks were measured at four sites, and in the second, the variation in seedbanks during the year was measured at one site. In each experiment the size and composition of the seedbanks were determined by germinating the seeds in soil samples.
In the first experiment, total seed numbers ranged from ~6000 to 12,000 per m2. There were no significant differences between sites for total seeds or for seeds of any species group except legumes which comprised only a small portion of the seedbanks. There were significant differences between patch types for total seeds and for the following species groups, medium tussock grasses, short tussock grasses, stoloniferous grasses, legumes and forbs but not large tussock grasses and sedges. Total seed numbers, and those of medium tussock grasses, stoloniferous grasses and forbs were highest in the lawn patches and lowest in the short sward patches. Legumes had higher numbers in the tall grassland patches than in other patch types.
In the second experiment, there were large differences between total seed numbers at the different sample dates (January, May, September and November). Numbers were highest in January and then declined throughout the year. This pattern was largely a reflection of the changes in numbers of forb seeds, the species group with the most seeds. There were no significant differences between patch types for total seeds but there were for medium tussock grasses, stoloniferous grasses, sedges and forbs. There was no relationship between the composition of the pasture sward and the composition of the seedbank for any of the three patch types. Twenty-eight species were allocated to persistent and transient seedbank types; all seedbank types occurred in all three patch types.
The major species in the seedbanks were sedges (Cyperus gracilis, C. sesquiflorus), forbs (Gamochaeta spp., Paronychia brasiliana, Daucus glochidiatus) and Eragrostis spp.
Daily changes in plant water content in western Queensland: implications for red kangaroo foraging times
Authors: Underhill S. , Grigg G. C. , Yates D. J.
Published: March 2005

We measured daily changes in plant water content to see if red kangaroos (Macropus rufus), in foraging at night, may gain more water than foraging by day. If so, it could be influential in dictating their time of foraging. The study was stimulated by work in Africa which showed that, by choosing to feed at night, gazelles are able to take advantage of increased plant water content. Daily changes in water content of 15 known forage plants were examined at Idalia National Park in semi-arid western Queensland in February, April and July 2002, during progressive drying of the country in an extraordinarily dry year. Of 29 day-night comparisons of plant water content, thirteen showed no difference, two (both of red spinach, Trianthema triquetra) showed a substantial increase at night, eight showed small but statistically significant increases, and six showed small but statistically significant decreases. We conclude that the choice of red kangaroos to forage at night is unlikely to be explained by nightly increases in plant water content.
Dramatic variation of the vomeronasal pheromone receptor gene repertoire among five orders of placental and marsupial mammals
Authors: Grus Wendy E. , Shi Peng , Zhang Ya-ping , Zhang Jianzhi
Published: March 2005

Pheromones are chemicals emitted and sensed by conspecifics to elicit social and sexual responses and are perceived in terrestrial vertebrates primarily by the vomeronasal organ (VNO). Pheromone receptors in the mammalian VNO are encoded by the V1R and V2R gene superfamilies. The V1R superfamily contains 187 and 102 putatively functional genes in the mouse and rat, respectively. To investigate whether this large repertoire size is typical among mammals with functional VNOs, we here describe the V1R repertoires of dog, cow, and opossum based on their draft genome sequences. The dog and cow have only 8 and 32 intact V1R genes, respectively. Thus, the intact V1R repertoire size varies by at least 23-fold among placental mammals with functional VNOs. To our knowledge, this size ratio represents the greatest among-species variation in gene family size of all mammalian gene families. Phylogenetic analysis of placental V1R genes suggests multiple losses of ancestral genes in carnivores and artiodactyls and gains of many new genes by gene duplication in rodents, manifesting massive gene births and deaths. We also identify 49 intact opossum V1R genes and discover independent expansions of the repertoire in placentals and marsupials. We further show a concordance between the V1R repertoire size and the complexity of VNO morphology, suggesting that the latter could indicate the sophistication of pheromone communications within species. In sum, our results demonstrate tremendous diversity and rapid evolution of mammalian V1R gene inventories and caution the generalization of VNO biology from rodents to all mammals.
Analysis of the Choristoneura fumiferana nucleopolyhedrovirus genome
Authors: de Jong Jondavid G. , Lauzon Hilary A. M. , Dominy Cliff , Poloumienko Arkadi , Carstens Eric B. , Arif Basil M. , Krell Peter J.
Published: March 2005

The double-stranded DNA genome of Choristoneura fumiferana nucleopolyhedrovirus (CfMNPV) was sequenced and analysed in the context of other group I nucleopolyhedroviruses (NPVs). The genome consists of 129 593 bp with a G+C content of 50·1 mol%. A total of 146 open reading frames (ORFs) of greater than 150 bp, and with no or minimal overlap were identified. In addition, five homologous regions were identified containing 7–10 repeats of a 36 bp imperfect palindromic core. Comparison with other completely sequenced baculovirus genomes revealed that 139 of the CfMNPV ORFs have homologues in at least one other baculovirus and seven ORFs are unique to CfMNPV. Of the 117 CfMNPV ORFs common to all group I NPVs, 12 are exclusive to group I NPVs. Overall, CfMNPV is most similar to Orgyia pseudotsugata MNPV based on gene content, arrangement and overall amino acid identity. Unlike other group I baculoviruses, however, CfMNPV encodes a viral enhancing factor (vef) and has two copies of p26.
Binding of human papillomavirus 16 E6 to p53 and E6AP is impaired by monoclonal antibodies directed against the second zinc-binding domain of E6
Authors: Lagrange Magali , Charbonnier Sebastian , Orfanoudakis Georges , Robinson Philip , Zanier Katia , Masson Murielle , Lutz Yves , Trave Gilles , Weiss Etienne , Deryckere François
Published: March 2005

The E6 protein of cancer-associated human papillomavirus type 16 (16E6) binds to p53 and, in association with E6AP, promotes its degradation through the ubiquitin–proteasome pathway. The aim of this work was to develop monoclonal antibodies against 16E6 and to test their effect on the binding of 16E6 to p53 and E6AP, and on the degradation of p53. It was shown that an antibody directed against the N terminus of 16E6 inhibited E6AP-dependent binding to p53 and degradation of p53, whereas two different antibodies directed to the second zinc-binding domain of 16E6 reduced 16E6 E6AP-independent binding to p53 and binding to E6AP but not degradation of p53.
Replication of a recombinant hepatitis E virus genome tagged with reporter genes and generation of a short-term cell line producing viral RNA and proteins
Authors: Thakral Deepshi , Nayak Baibaswata , Rehman Shagufta , Durgapal Hemlata , Panda Subrat Kumar
Published: March 2005

Hepatitis E virus (HEV) replication has been demonstrated in HepG2 cells transfected with full-length in vitro transcripts of an infectious cDNA clone. This cDNA clone was modified to generate several subgenomic HEV replicons with fused reporter genes. In vitro-transcribed capped RNAs generated from these were transfected into HepG2 cells. Negative-strand RNA was detected, indicating the occurrence of replication. The replicon containing an in-frame fusion of HEV ORF2 with enhanced green fluorescent protein (EGFP) was positive for fluorescence, whereas no signal was observed when the replicase domain was deleted. An HEV ORF3–EGFP in-frame fusion did not yield fluorescence. Deletions introduced into ORF2 did not affect the replication competency of the viral RNA. To explore the possibility of using a reporter-gene assay to monitor the synthesis of plus- and minus-strand RNA, the EGFP gene fused to the encephalomyocarditis virus internal ribosome entry site (IRES) was inserted into partially deleted ORF2 of HEV, in both the sense [HEV–IRES–EGFP(+)] and antisense [HEV–IRES–EGFP(−)] orientations. HepG2 cells transfected with HEV–IRES–EGFP(+) and HEV–IRES–EGFP(−) vectors were positive for EGFP fluorescence. To quantify HEV replication, EGFP was replaced with Renilla luciferase (RLuc). HEV–IRES–RLuc(+) showed approximately 10-fold higher luminescence than HEV–IRES–RLuc(−). There was complete loss of activity when the helicase–replicase domain in HEV–IRES–RLuc(−) was deleted. A short-term HepG2 cell line containing the full-length viral genome in the pcDNA3 vector was established. Viral RNA and proteins (RdRp, pORF2 and pORF3) could be detected in the geneticin-resistant cells, even after the seventh passage. In the absence of a reliable cell-culture system to study HEV biology, these reporter replicons, as well as the cell line, bestow immense utility.
Application of the theory of constraints to a bottleneck operation in a manufacturing plant
Authors: Pegels C. Carl , Watrous Craig
Published: March 2005

Purpose

The purpose of this paper is to describe a study of the successful application of the theory of constraints (TOC) to a manufacturing plant operations problem. The TOC application required the identification of a bottleneck constraint in the manufacturing process which limited through‐put and thus negatively affected plant productivity and efficiency.

Design/methodology/approach

The methodology used was a detailed case study of the bottleneck in the manufacturing process. The bottleneck in this case was the mold‐changing operations, consisting of a plastic injection process for heavy‐duty truck‐lighting systems components.

Findings

It was found that to eliminate the bottleneck four separate solution approaches were applied to the problem, and these four solutions collectively eliminated the bottleneck constraint.

Research limitations/implications

The limitation of this approach is that the application of the TOC method is highly specific to the particular operation.

Originality/value

On completion of the study the mold‐changing process improvements resulted in increased through‐put and concomitant improvements in productivity and efficiency in the heavy‐duty truck‐lighting systems plant.
A simulation‐based comparison of TOC and traditional accounting performance measures in a process industry
Authors: Mehra Satish , Inman R. Anthony , Tuite Gregory
Published: March 2005

Purpose

Aims to compare performance measurement of a continuous process manufacturing operation under two accounting systems – a traditional cost accounting system and the theory of constraints (TOC) system.

Design/methodology/approach

Using a computer‐based simulation methodology to capture operational performance, it is found that the TOC‐based accounting system presents a more realistic state of performance scenario.

Findings

Findings from this research indicate that businesses using a TOC‐based system can improve their performance more accurately, and hence gain a sustainable competitive position in the future.

Research limitations/implications

This research is limited to continuous process manufacturing operations.

Originality/value

The research makes a significant contribution to the knowledge of performance measurement.
A neuro‐computing approach to the thermal profile control of the second‐side reflow process in surface mount assembly
Authors: Tsai Tsung‐Nan , Yang Taho
Published: March 2005

Purpose

A neural‐network‐based predictive model is proposed to model the second‐side thermal profile reflow process in surface mount assembly with a view to facilitating the oven set‐up procedure and improving production yield.

Design/methodology/approach

This study performs a 38−4 fractional factorial experimental twice to collect the thermal‐profile data from a second‐side board. The first experiment has components on the second side only, while the second experiment also has additional components on the primary side. A back‐propagation neural network (BPN) is then used to model the relationship between control variables and thermal‐profile measures.

Findings

Empirical results illustrate the efficiency and effectiveness of the proposed BPN in solving the second‐side thermal‐profile prediction and control problem.

Originality/value

There is no study dedicated to the investigation of the second‐side thermal‐profile variance with and without the presence of primary‐side components. The study suggests that a variant oven‐setting strategy for the second‐side reflow process is important to ensure reflow‐soldering quality.
The validity of serologic tests for Trypanosoma cruzi and the effectiveness of transfusional screening strategies in a hyperendemic region
Authors: Pirard Marianne , Iihoshi Naomi , Boelaert Marleen , Basanta Paulino , López Freddy , Van der Stuyft Patrick
Published: March 2005

BACKGROUND: This study aims at obtaining unbiased estimates of the sensitivity and specificity of existing screening tests for Trypanosoma cruzi and at simulating the effectiveness of alternative screening strategies at different prevalence rates.

STUDY DESIGN AND METHODS: A systematic random sample of 400 was taken from 1200 banked serum samples of donors screened between August 1998 and January 1999 in Santa Cruz, Bolivia. Samples were tested with indirect hemagglutination test (IHA), indirect immunofluorescence assay (IFA), and four enzyme‐linked immunosorbent assays (ELISAs). Sensitivity and specificity of tests were estimated through latent class analysis.

RESULTS: The sensitivity of individual tests ranged from 96.5 to 100 percent, and their specificity from 87.0 to 98.9 percent. Combinations of two tests used in parallel would, even at 40 percent prevalence, only miss approximately 1 infected unit per 10,000 screened. At 5 percent prevalence, however, they would yield 75 to 120 false‐positive units per 1000 units screened. Parallel testing with IHA plus ELISA or with IHA plus IFA is marginally more cost‐effective, compared to single IHA testing, than single ELISA or single IFA testing, regardless of the T. cruzi prevalence.

CONCLUSIONS: Routine blood donor screening for T. cruzi with a single test results in unacceptable numbers of false‐negative samples in highly endemic areas or in at risk population groups. Adding a second test seems mandatory, but which one to choose depends on local cost components and feasibility.
Efficacy of Epstein‐Barr virus removal by leukoreduction of red blood cells
Authors: Qu Lirong , Xu Shushen , Rowe David , Triulzi Darrell
Published: March 2005

BACKGROUND: Epstein‐Barr virus (EBV) infection results in life‐long carriage of latent virus in B lymphocytes in the majority of the adult population, including blood donors. The removal of EBV from red blood cell (RBC) components by leukoreduction was assessed.

STUDY DESIGN AND METHODS: Sixteen randomly selected fresh AS‐5 units were leukoreduced by filtration. B lymphocytes from preleukoreduction specimens and mononuclear cells (MNCs) from postleukoreduction specimens were assayed for EBV DNA with sensitive real‐time polymerase chain reaction (PCR).

RESULTS: EBV genomes were detected in CD19+ B cells in 14 of 16 preleukoreduced RBC units. EBV genomic copy number in the units ranged from 0.18 to 96.84 per 105 B lymphocytes representing approximately 135 to 72,630 total EBV genomes per bag. Leukoreduction rendered all but one unit EBV‐negative by PCR. The lone PCR‐positive unit after leukoreduction amplified 1.2 EBV genome copies from MNCs recovered from the entire unit of leukoreduced RBCs; this unit had the highest EBV viral load before leukoreduction (72,630 EBV genomes).

CONCLUSIONS: These results indicate that a 4‐log reduction of EBV genomic copy number can be achieved with leukoreduction of RBC units and renders most RBC units EBV‐negative by sensitive PCR.
Evaluating explanations of the Australian ‘heroin shortage’
Authors: Degenhardt Louisa , Reuter Peter , Collins Linette , Hall Wayne
Published: March 2005

Aims  In this paper we outline and evaluate competing explanations for a heroin shortage that occurred in Australia during 2001 with an abrupt onset at the beginning of 2001.

Methods  We evaluated each of the explanations offered for the shortage against evidence from a variety of sources: government reports, police and drug law enforcement documents and briefings, key informant (KI) interviews, indicator data and research data.

Results  No similar shortage occurred at the same time in other markets (e.g. Vancouver, Canada or Hong Kong) whose heroin originated in the same countries as Australia’s. The shortage was due most probably to a combination of factors that operated synergistically and sequentially. The heroin market had grown rapidly in the late 1990s, perhaps helped by a decline in drug law enforcement (DLE) in Australia in the early 1990s that facilitated high‐level heroin suppliers in Asia to establish large‐scale importation heroin networks into Australia. This led to an increase in the availability of heroin, increasingly visible street‐based drug markets, increased purity and decreased price of heroin around the country. The Australian heroin market was well established by the late 1990s, but it had a low profit margin with high heroin purity, and a lower price than ever before. The surge in heroin problems led to increased funding of the Australian Federal Police and Customs as part of the National Illicit Drug Strategy in 1998–99, with the result that a number of key individuals and large seizures occurred during 1999–2000, probably increasing the risks of large‐scale importation. The combination of low profits and increased success of law enforcement may have reduced the dependability of key suppliers of heroin to Australia at a time when seized heroin was becoming more difficult to replace because of reduced supplies in the Golden Triangle. These factors may have reduced the attractiveness of Australia as a destination for heroin trafficking.

Conclusions  The Australian heroin shortage in 2001 was due probably to a combination of factors that included increased effectiveness of law enforcement efforts to disrupt networks bringing large shipments of heroin from traditional source countries, and decreased capacity or willingness of major traffickers to continue large scale shipments to Australia.
Selection and socialization effects of fraternities and sororities on US college student substance use: a multi‐cohort national longitudinal study
Authors: McCabe Sean Esteban , Schulenberg John E. , Johnston Lloyd D. , O'Malley Patrick M. , Bachman Jerald G. , Kloska Deborah D.
Published: March 2005

Aims  To examine how membership in fraternities and sororities relates to the prevalence and patterns of substance use in a national sample of full‐time US college students.

Design  Nationally representative probability samples of US high school seniors (modal age 18 years) were followed longitudinally across two follow‐up waves during college (modal ages 19/20 and 21/22).

Setting  Data were collected via self‐administered questionnaires from US high school seniors and college students.

Participants  The longitudinal sample consisted of 10 cohorts (senior years of 1988–97) made up of 5883 full‐time undergraduate students, of whom 58% were women and 17% were active members of fraternities or sororities.

Findings  Active members of fraternities and sororities had higher levels of heavy episodic drinking, annual marijuana use and current cigarette smoking than non‐members at all three waves. Although members of fraternities reported higher levels than non‐members of annual illicit drug use other than marijuana, no such differences existed between sorority members and non‐members. Heavy episodic drinking and annual marijuana use increased significantly with age among members of fraternities or sororities relative to non‐members, but there were no such differential changes for current cigarette use or annual illicit drug use other than marijuana.

Conclusions  The present study provides strong evidence that higher rates of substance use among US college students who join fraternities and sororities predate their college attendance, and that membership in a fraternity or sorority is associated with considerably greater than average increases in heavy episodic drinking and annual marijuana use during college. These findings have important implications for prevention and intervention efforts aimed toward college students, especially members of fraternities and sororities.
The rise of buprenorphine prescribing in England: analysis of NHS regional data, 2001–03
Authors: De Wet Cornelis J. , Reed Laurence J. , Bearn Jennifer
Published: March 2005

Aims  Since its launch in the prescribing market in 1999 for the treatment of opiate dependence, buprenorphine has rapidly become established as an alternative to methadone treatment in the United Kingdom. In the absence of evidence of its clinical superiority over methadone, and given its high relative cost, we sought to examine the impact of buprenorphine availability on opiate treatment services in England.

Methods  Quarterly buprenorphine and methadone community prescription figures were obtained for 28 Strategic Health Authorities (SHAs) in England, for the 2‐year period September 2001 to September 2003. Rates of buprenorphine prescribing (as proportion of all opiate prescriptions) were examined over time by number of prescriptions and net ingredient cost.

Results  Buprenorphine prescription rates increased disproportionately to methadone in all 28 SHAs. By the end of 2003 the number of buprenorphine prescriptions had increased to 23% of all opiate prescriptions, but accounted for 45% of opiate prescription costs in England. Buprenorphine prescribing rates varied substantially across different regions.

Conclusions  Buprenorphine prescribing has increased dramatically and represents a disproportionately large fraction of community opiate prescribing costs. The marked regional variation suggests the need for further research and the development of national guidelines to support rational prescribing and equitable access to treatment.
Expressed sequence tags from Diabrotica virgifera virgifera midgut identify a coleopteran cadherin and a diversity of cathepsins
Authors: Siegfried B. D. , Waterfield N. , Ffrench‐Constant R. H.
Published: March 2005

The Western corn rootworm is the major pest of corn in the USA and has recently become the target for insect‐resistant transgenic crops. Transgenic crops have switched the focus for identifying insecticide targets from the insect nervous system to the midgut. Here we describe a collection of 691 sequences from the Western corn rootworm midgut, 27% of which predict proteins with no matches in current databases. Of the remaining sequences, most predict proteins with either catalytic (62%) or binding (19%) functions, as expected for proteins expressed in the insect midgut. The utility of this approach for the identification of targets for novel toxins is demonstrated by analysis of the first coleopteran cadherin gene, a putative Bt receptor, and a large class of cysteine‐proteases, the cathepsins.
Actometry in measuring the symptom severity of restless legs syndrome
Authors: Tuisku K. , Holi M. M. , Wahlbeck K. , Ahlgren A. J. , Lauerma H.
Published: March 2005

In a previous, controlled study we demonstrated that the general lower limb activity measured by three‐channel actometry is a promising objective measure of restless legs syndrome (RLS) severity. In the present study we have further evaluated the method in measuring RLS symptom severity in an open, single‐day pramipexole intervention with 15 RLS patients. Both our standardized actometric parameters (nocturnal lower limb activity and controlled rest activity) decreased significantly during the intervention in parallel with the subjectively reported relief of RLS symptoms.