bluuebunny/crossref_metadata_2025 huggingface dataset:
Earthward flowing plasmoid: Structure and its related ionospheric signature
Authors: Zong Q.‐G. , Fu S. Y. , Baker D. N. , Goldstein M. L. , Song P. , Slavin J. A. , Fritz T. A. , Cao J. B. , Amm O. , Frey H. , Korth A. , Daly P. W. , Reme H. , Pedersen A.
Published: July 2007

An earthward moving plasmoid has been observed on 28 October 2002 by the Cluster spacecraft with simultaneous auroral viewing by the IMAGE satellite. This offers the opportunity to ascertain the optical and the evolutional signatures in the ionosphere of the earthward moving plasmoid. The ionospheric signatures observed in this paper are not substorm‐related. Both the ground‐based measurements and IMAGE satellite auroral observations show the ionospheric signatures moving to lower latitudes, when the earthward moving plasmoid is observed by the Cluster spacecraft. The intensity of the current in the center of the plasmoid is found to be weaker than that in the adjacent region. Also, the directions of the current in the central part of the plasmoid, different from the background cross‐tail current, are more field‐aligned. Those facts are consistent with the tail current closes through the substorm‐like current wedge, since the cross‐tail current is blocked by the plasmoid. On the other hand, the current in the earthward plasmoid may close through the interhemisphere. In this paper we demonstrate that the magnetic structures, plasmoids and flux ropes, will transport flux and energy from the distant tail to the Earth.
Statistical study of low‐energy heliosphere particle fluxes from 1.4 to 5 AU over a solar cycle
Authors: Denker C. , Reza J. Z. , Nelson A. J. , Patterson J. D. , Armstrong T. P. , Maclennan C. G. , Lanzerotti L. J.
Published: July 2007

Throughout the entire Ulysses mission, the Heliosphere Instrument for Spectra, Composition, and Anisotropy at Low Energies (HI‐SCALE) has collected measurements of low‐energy interplanetary ions and electrons. Time series of electron, proton, and ion fluxes have been obtained since 1990. We present statistical studies of high‐resolution ion and electron energy spectra (∼50 keV to ∼5 MeV) as measured by the HI‐SCALE instrument on the Ulysses spacecraft over a time interval longer than a solar cycle (1990 to 2004). Ulysses is the only spacecraft that continually measured the inner (∼1.4 to ∼5 AU) heliosphere particle population during these years. The data thus provide measures of the lower‐energy population of particles that a spacecraft traveling outward from Earth would have encountered and that also could have impacted the atmosphere and surface of Mars and of its satellites during this interval. Comparisons of Ulysses particle fluxes with those from the Electron, Proton, and Alpha Monitor (EPAM) instrument on the Advanced Composition Explorer (ACE) spacecraft (the HI‐SCALE backup instrument) have shown that azimuthal and heliolatitude dependencies of particle fluxes in the inner heliosphere following solar events are not as extreme as might be expected. Thus the Ulysses measurements, while taken over a range of heliolatitudes, can provide important statistical information that can be used to estimate the low‐energy radiation dosages and potential sputtering fluxes to planetary surfaces and to heliosphere spacecraft surfaces and solar arrays over a solar cycle.
Alteration of the subducting oceanic lithosphere at the southern central Chile trench–outer rise
Authors: Contreras‐Reyes Eduardo , Grevemeyer Ingo , Flueh Ernst R. , Scherwath Martin , Heesemann Martin
Published: July 2007

Hydrothermal circulation and brittle faulting processes affecting the oceanic lithosphere are usually confined to the upper crust for oceanic lithosphere created at intermediate to fast spreading rates. Lower crust and mantle rocks are therefore relatively dry and undeformed. However, recent studies at subduction zones suggest that hydration of the oceanic plate is most vigorous at the trench–outer rise, where extensional bending‐related faulting affects the hydrogeology of the oceanic crust and mantle. To understand the degree of hydration, we studied the seismic velocity structure of the incoming Nazca plate offshore of southern central Chile (∼43°S); here the deep‐sea trench is heavily filled with up to 2 km of sediments. Seismic refraction and wide‐angle data, complemented by seismic reflection imaging of sediments, are used to derive a two‐dimensional velocity model using joint refraction and reflection traveltime tomography. The seismic profile runs perpendicular to the spreading ridge and trench axes. The velocity model derived from the tomography inversion consists of a ∼5.3‐km‐thick oceanic crust and shows P wave velocities typical for mature fast spreading crust in the seaward section of the profile, with uppermost mantle velocities as fast as ∼8.3 km/s. Approaching the Chile trench, seismic velocities are significantly reduced, however, suggesting that the structures of both the oceanic crust and uppermost mantle have been altered, possibly due to a certain degree of fracturing and hydration. The decrease of the velocities roughly starts at the outer rise, ∼120 km from the deformation front, and continues into the trench. Even though the trench is filled with sediment, basement outcrops in the outer rise frequently pierce the sedimentary blanket. Anomalously low heat flow values near outcropping basement highs indicate an efficient inflow of cold seawater into the oceanic crust. Hydration and crustal cracks activated by extensional bending‐related faulting are suggested to govern the reduced velocities in the vicinity of the trench. Considering typical flow distances of 50 km, water might be redistributed over most of the trench–outer rise area. Where trapped in faults, seawater may migrate down to mantle depth, causing up to ∼9% of serpentinization in at least the uppermost ∼2 km of the mantle between the outer rise and the trench axis.
Tsunami forecast using an adaptive inverse algorithm for the Peru‐Chile source region
Authors: Sánchez Alejandro , Cheung Kwok Fai
Published: July 2007

The inverse method provides tsunami forecasts through regression of near‐field water‐level data against a set of mareograms computed for unit slip of predetermined subfaults. The present paper describes an improvement to this inverse method by resolving the timing of subfault movement in the inversion. This provides additional degrees of freedom in the regression analysis and accounts for rupture propagation and rise time of tsunamigenic earthquakes. The method is implemented for the Peru‐Chile subduction zone, in which the seismic source parameters are deduced from previous studies of seismotectonics and historical earthquakes. A hindcast analysis of the 1995 Antofagasta‐Chile tsunami demonstrates the capability of the adaptive inverse algorithm in improving the near‐field inversion results and consequently the far‐field forecast.
Storm time, short‐lived bursts of relativistic electron precipitation detected by subionospheric radio wave propagation
Authors: Rodger Craig J. , Clilverd Mark A. , Nunn David , Verronen Pekka T. , Bortnik Jacob , Turunen Esa
Published: July 2007

In this study we report on ground‐based observations of short bursts of relativistic electron precipitation (REP), detected by a subionospheric propagation sensor in Sodankylä, Finland during 2005. In two ∼4 hour case study periods from L = 5.2, around local midnight, several hundred short‐lived radio wave perturbations were observed, covering a wide range of arrival azimuths. The vast majority (∼99%) of these perturbations were not simultaneous with perturbations on other paths, consistent with a precipitation “rainstorm” producing ionospheric changes of small spatial sizes around the Sodankylä receiver. The recovery time of these radio wave perturbations are ∼1.2 s, which is consistent with the modeled effects of a burst of >2 MeV precipitating electrons. This agrees with satellite observations of the microburst energy spectrum. The energetic nature of the precipitation which produces the FAST perturbations suggests that they should be observable in both day and night conditions. While it is widely assumed that satellite‐detected REP microbursts are due to wave‐particle interactions with very low‐frequency chorus waves, the energy spectra predicted by our current models of chorus propagation and wave‐particle interaction are not consistent with the experimentally observed radio wave perturbations presented here or previously reported satellite observations of REP microbursts. The results inferred from both the satellite and subionospheric observations, namely the absence of a large, dominant component of <100 keV precipitating electrons, fundamentally disagrees with a mechanism of chorus‐driven precipitation. Nonetheless, further work on the modeling of chorus‐driven precipitation is required.
Influence of antigens and adjuvants on the production of gamma‐interferon and antibody by ovine lymphocytes
Authors: Emery D. L. , Rothel J. S. , Wood P. R.
Published: July 2007

The production of gamma‐interferon (γ‐IFN) and antigen‐specific immunoglobulin isotypes was monitored in sheep given primary and secondary inocula of protein and polysaccharide antigens with or without adjuvants. In efferent lymph from prefemoral nodes draining the site of inoculation, γ‐IFN levels increased within 24 h after injection of adjuvants Quill A, dextran sulfate (DXS) and 6 days after oil adjuvants in saline. The increased synthesis of γ‐IFN was prolonged by 1–2 days by the presence of adjuvanted antigen, but the major stimulus to γ‐IFN production was provided by the adjuvant. Alhydrogel (AH) did not initiate γ‐IFN synthesis. Following a second inocula of antigen in saline, increased levels of γ‐IFN were detected in efferent lymph after 3–4 h, and persisted for at least 2 days. Following cultivation of leucocytes from immunized sheep with specific antigen in vitro, strong positive correlations between levels of interleukin (IL) IL‐2, ‐IFN, proliferative responses and antibody titres were observed. However, after analysis of the antigen‐specific isotypes of immunoglobulin (Ig) there was no correlation between the production of γ‐IFN and particular Ig isotypes. Together with findings that AH did not preferentially induce IgG1 or IgG2, these results suggest that the specific subpopulations of helper T lymphocytes which regulate the production of antibody isotypes by differential secretion of γ‐IFN or IL‐4, are not as clearly defined in sheep as in mice.
Mapping the dextran sulfate binding site on CD2
Authors: Warren Hilary S. , Parish Christopher R.
Published: July 2007

This study has analysed the binding of a series of anti‐CD2 monoclonal antibodies (MoAbs) to T cells in the presence of the sulfated polysaccharide dextran sulfate (2·3 sulfates/monosaccharide, 500 kDa) (DXS) to define the DXS binding site on CD2. The results show that DXS interacts primarily at the T112 epitope. Thus five anti‐CD2 MoAbs which bound to the T112 epitope were inhibited in their binding by DXS. In contrast, seven anti‐CD2 MoAbs that totally inhibited sheep red blood cells (SRBC) rosetting (identifying the T111 epitope) were unaffected in their binding to T cells in the presence of DXS. Three MoAbs which partially inhibited SRBC rosetting and thereby defining only part of the T111 epitope, were also inhibited in their binding by DXS. Consistent with the conclusion that the DXS binding site on CD2 is associated with the T112 epitope was the observation that interaction of DXS with CD2 resulted in augmented binding of the four MoAbs defining the T113 epitope, possibly reflecting an increased expression of the T113 (activation, CD2R) epitope of CD2. Collectively, the data presented support the notion that a natural ligand for the T112 epitope of CD2 will be identified as a sulphated carbohydrate structure.
Antibodies to type II collagen in SLE: A role in the pathogenesis of deforming arthritis?
Authors: Choi Edward K. K. , Gatenby Paul A. , Bateman John F. , Cole William G.
Published: July 2007

The role of autoimmunity to type II collagen in the arthritis of systemic lupus erythematosus (SLE) has been assessed by ELISA and by Western blotting cyanogen bromide cleavage fragments separated on SDS‐PAGE. The results show that antibodies to both native and heat‐denatured collagen are quite common in SLE when measured by ELISA. Of particular interest is the demonstration of an association between antibodies to the CB 11 peptide and deforming arthritis in SLE. This is the arthritogenic peptide in murine models of collagen II‐induced autoimmune arthritis and the results presented here suggest a potential pathogenetic role in the deforming arthritis of SLE for this specific subset of antibodies to type II collagen.
Clonal analysis of the effect of iron on human cytotoxic and proliferating T lymphocytes
Authors: Rudd Michael J. , Good Michael F. , Chapman D. E. , Powell L. W. , Halliday J. W.
Published: July 2007

The immunoregulatory effect of non‐transferrin‐bound iron (Fe3+) on the proliferative and cytotoxic responses of normal human T lymphocytes was studied using a sensitive limit‐dilution technique capable of detecting the responses of individual lymphocytes. Iron, present in the form of ferric citrate at concentrations from 0·03 to 1·0 mmol/L. significantly reduced the cloning frequency of peripheral blood T lymphocytes. The effect of iron appeared, however, to be targeted to individual clones in that some clones that did grow in the presence of iron achieved a normal rate of proliferation. Thus, iron was not non‐specifically toxic. At these same concentrations ferric citrate also produced significant reductions in the cloning frequency of CD4 + CD8‐ precursor T lymphocytes. Reductions in the response of T lymphocyte precursors capable of cytotoxic activity occurred in the presence of ferric citrate from 0·1 to 1·0 mmol/L. These data support the hypothesis that non‐transferrin‐bound iron has an immunoregulatory role in cell‐mediated immunity.
Inhibition of adhesion of Haemophilus influenzae to buccal cells by respiratory secretions
Authors: Taylor Diana C. , Cripps Allan W. , Clancy Robert L.
Published: July 2007

The ability of salivary secretions and sputum sol from patients with chronic bronchitis to inhibit the adhesion of non‐serotypable Haemophilus influenzae to human buccal epithelial cells has been examined. Specific H. influenzae antibodies were measured by an enzyme‐linked immunosorbent assay (ELISA). Saliva and sputum levels of anti‐ H. influenzae immunoglobulin A (IgA) antibody were related inversely to buccal cell adherence (r = ‐ 0·92). Absorption of saliva and sputum sol with H. influenzae removed antibody detected by ELISA but only partially removed inhibition of attachment of bacteria. In patients with a history of recurrent bronchitis significantly more inhibitory activity remained after absorption of the secretory IgA (sIgA) specific antibody compared with patients who were resistant to acute episodes of infection (P <0·05). These observations suggest that factors, other than sIgA. are present in respiratory secretions and are capable of modulating H. influenzae attachment to buccal epithelial cells.
Hybrid myeloma cells which secrete heterodimetric IgG: A model to study the N‐linked glycan
Authors: LEE S‐O. , PORETZ R. D.
Published: July 2007

Fundamental questions remain unanswered regarding the effect of the acceptor polypeptide structure on the fine structure of the N‐linked glycan of glycoproteins and conversely, the effect of the glycan structure of IgG on the function and structure of the protein. The construction of myeloma hybrids capable of secreting multiple IgG which differ with regard to the fine structure of their N‐linked oligosaccharides would be a valuable model for studying these questions. P3X63Ag8 secretes an IgG1 which possesses an oligosaccharide at Asn297 that differs in fine structure from the analogous glycan of the IgG2b secreted by Sp2/HLBu. Fusion hybrids of these cells secrete parental IgG1, and to a lesser degree IgG2b, as well as a heterodimeric IgG containing both the γ1 and γ2b chains. The oligosaccharide of each chain is identical in structure to the appropriate parental IgG. Such cells allow for the analysis of acceptor properties that influence glycan fine structure, as well as the role of glycan structure on the stability of the IgG.
Differential eicosanoid synthesis by murine fetal thymic non‐lymphoid cells
Authors: PENDINO KIMBERLY J. , CHEPENIK K. P. , SCHMIDT R. R.
Published: July 2007

The temporal patterns of synthesis of prostaglandin (PG)E2 and PGI2 by organ‐cultured fetal thymic lobes and the cell population(s) responsible for synthesis of such products within the murine fetal thymus have been investigated. Embryonic day 14 thymic lobes were organ‐cultured in defined media for 14 days and the media were collected every 24 h and replaced with fresh media. Collected media were processed for quantitation of either PGE2 or PGI2. Lobes were also cultured in 2′‐deoxyguanosine (1.35 mmol/L) to produce an enriched non‐lymphoid population. The per cent cyclooxygenase‐positive cells within non‐lymphoid cell‐enriched lobes as well as the capacity of such lobes to synthesize either PGE2 or PGI2 were determined and compared with that of intact thymic lobes. Results demonstrate that fetal thymic lobes, in vitro, differentially synthesize PGI2 and synthesize PGE2 at a constant rate. Moreover, lobes enriched for non‐lymphoid cells contain a greater percentage of cyclooxygenase‐positive cells and synthesize increased amounts of eicosanoids per 104 cells compared with controls.
Intradermal and percutaneous transudation of IgG1 and transferrin in sheep
Authors: COLDITZ I. G. , ALTMANN K. G. , WATSON D. L.
Published: July 2007

The leakage of [125I]‐IgG1 into skin sites following injection of mediators of enhanced vascular permeability and during induction of transudates on the skin surface under negative pressure was examined to determine whether IgG is selectively transported into cutaneous transudates. 111In‐transferrin was employed as a marker of plasma leakage unaided by selective transport. The leakage of IgG1 into interstitial spaces of untreated skin, into inflammatory transudates and into transudate fluid drawn to the skin surface under vacuum occurred at a lower rate than did leakage of transferrin. No evidence was found in favour of a selective transport mechanism to aid transport of IgG1 into extravascular skin compartments.
The importance of T cell homing and the spleen in reaching a balance between malaria immunity and immunopathology: The moulding of immunity by early exposure to cross‐reactive organisms
Authors: GOOD MICHAEL F. , CURRIER JEFF
Published: July 2007

It takes a number of years to develop clinical immunity to malaria and malaria pathology is also most evident a number of years after birth. T cells are known to play an important role in defence from malaria parasites but may also contribute to the disease symptoms associated with malaria. T cells which react against malaria parasites have arisen through stimulation with organisms which cross‐react with malaria or through exposure to the malaria parasites themselves and express a memory phenotype (CD45Ro+, CD45Ra‐, CD4+). T clones which have arisen through exposure to cross‐reactive organisms may he expected to home to the tissues where initial exposure occurred as determined by tissue‐specific adhesion molecules on the lymphocyte surface. Such tissues may not be appropriate to parasite killing and localization of T cells in such sites may contribute to the immunopathology of malaria. The sharp increase in immunity and decline in pathology observed in later childhood in malaria endemic areas may result from an increase in the number of T cells induced by the parasite itself (as opposed to cross‐reactive organisms). Such T cells may not have a preferential trafficking to other organs and may be more likely to circulate through the spleen. Splenic changes may also allow more malaria‐specific T cells to concentrate in the spleen and may facilitate interactions between T cells, monocytes, neutrophils and parasites resulting in parasite death. Whereas cytokines secreted by parasite‐reactive T cells in all locations may contribute to cerebral malaria and other forms of pathology, cytokines in the spleen at least, should directly contribute to parasite death.
Observation of three cases of temporomandibular joint osteoarthritis and mandibular morphology during adolescence using helical CT
Authors: Yamada K. , Saito I. , Hanada K. , Hayashi T.
Published: July 2007

summary  Temporomandibular joint (TMJ) osteoarthritis (OA) is a potential cause of craniofacial deformity. If TMJ OA appears during orthodontic treatment, the mandible usually rotates posteriorly, resulting in an unsatisfactory profile, especially in patients with pre‐treatment mandibular retrusion. Although it is important to confirm the kind of TMJ pathosis at the start of orthodontic treatment, the relationship between TMJ OA, condylar remodelling and changes in craniofacial morphology remains unclear because of a lack of longitudinal studies. Elucidating this relationship might allow better prediction of post‐treatment craniofacial morphology. In the present case reports, helical computed tomography and cephalometry were used to analyse relationships between the pattern and location of condylar remodelling and the changes in craniofacial morphology in three patients with TMJ OA.
Electronic structure of germanium nitride considered for gate dielectrics
Authors: Yang M. , Wang S. J. , Feng Y. P. , Peng G. W. , Sun Y. Y.
Published: July 2007

First-principles calculations based on density-functional theory and the local-density approximation have been used to investigate structural, electronic, and optical properties of α, β, and γ phases of germanium nitride (Ge3N4). β-Ge3N4 was found to be the most stable among the three structures, and it has a very small lattice mismatch with Ge, which indicates that it could be grown epitaxially on Ge. The calculated band gaps of α-, β-, and γ-Ge3N4 are about 3.15, 3.07, and 2.33eV, and the corresponding static dielectric constants are 4.70, 4.74, and 6.27, respectively, within local-density approximation. Results of our calculations indicate that the band gap and static dielectric constants of Ge3N4, as well as Si3N4, could satisfy the requirements of gate dielectrics for Ge-based field effect transistors.
Rotationally resolved spectra of jet-cooled VMo
Authors: Nagarajan Ramya , Sickafoose Shane M. , Morse Michael D.
Published: July 2007

The authors report the first gas-phase spectroscopic investigation of diatomic vanadium molybdenum (VMo). The molecules were produced by laser ablation of a VMo alloy disk and cooled in a helium supersonic expansion. The jet-cooled VMo molecules were studied using resonant two-photon ionization spectroscopy. The ground state has been demonstrated to be of Δ5∕22 symmetry, deriving from the dσ2dπ4dδ3sσ2 electronic configuration. Rotational analysis has established the ground state bond length and rotational constant as r0″=1.87657(23)Å and B0″=0.142861(35)cm−1, respectively, for V51Mo98 (1σ error limits). Transitions to states with Ω′=2.5, Ω′=3.5, and Ω′=1.5 have been recorded and rotationally analyzed. A band system originating at 15091cm−1 has been found to exhibit a vibrational progression with ωe′=752.7cm−1, ωe′xe′=12.8cm−1, and r0′=1.90Å for V51Mo98. The measured bond lengths (r0) of V2, VNb, Nb2, Cr2, CrMo, Mo2, VCr, NbCr, and VMo have been used to derive multiple bonding radii for these elements of r(V)=0.8919Å, r(Nb)=1.0424Å, r(Cr)=0.8440Å, and r(Mo)=0.9725Å. These values reproduce the bond lengths of all nine diatomics to an accuracy of ±0.012Å or better.
Sound propagation in a highly damped Mo6S3I6 nanowire network measured by femtosecond pump-probe spectroscopy
Authors: Kušar Primož , Mihailovic Dragan
Published: July 2007

Using femtosecond pump-probe spectroscopy we have measured the propagation of sound in a randomly formed Mo6S3I6 nanowire network for the first time. The pump-probe technique allows us to measure the reflection of an optical pulse from a propagating acoustical disturbance in spite of very high sound damping in the rather porous network medium. We use a range of different laser wavelengths from 0.7 to 2.4 μm and a measurement of the refractive index n, to obtain a value of sound velocity v=1630±160 m∕s.
Novel platform for minimizing cell loss on separation process: Droplet-based magnetically activated cell separator
Authors: Kim Youngho , Hong Su , Lee Sang Ho , Lee Kangsun , Yun Seok , Kang Yuri , Paek Kyeong-Kap , Ju Byeong-Kwon , Kim Byungkyu
Published: July 2007

To reduce the problem of cell loss due to adhesion, one of the basic phenomena in microchannel, we proposed the droplet-based magnetically activated cell separator (DMACS). Based on the platform of the DMACS—which consists of permanent magnets, a coverslip with a circle-shaped boundary, and an injection tube—we could collect magnetically (CD45)-labeled (positive) cells with high purity and minimize cell loss due to adhesion. To compare separation efficiency between the MACS and the DMACS, the total number of cells before and after separation with both the separators was counted by flow cytometry. We could find that the number (3241∕59940) of cells lost in the DMACS is much less than that (22360∕59940) in the MACS while the efficiency of cell separation in the DMACS (96.07%) is almost the same as that in the MACS (96.72%). Practically, with fluorescent images, it was visually confirmed that the statistical data are reliable. From the viability test by using Hoechst 33 342, it was also demonstrated that there was no cell damage on a gas-liquid interface. Conclusively, DMACS will be a powerful tool to separate rare cells and applicable as a separator, key component of lab-on-a-chip.
Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy
Authors: Diedrich Jonathan , Rehse Steven J. , Palchaudhuri Sunil
Published: July 2007

A pathogenic strain of bacteria, Escherichia coli O157:H7 (enterohemorrhagic E. coli or EHEC), has been analyzed by laser-induced breakdown spectroscopy (LIBS) with nanosecond pulses and compared to three nonpathogenic E. coli strains: a laboratory strain of K-12 (AB), a derivative of the same strain termed HF4714, and an environmental strain, E. coli C (Nino C). A discriminant function analysis (DFA) was performed on the LIBS spectra obtained from live colonies of all four strains. Utilizing the emission intensity of 19 atomic and ionic transitions from trace inorganic elements, the DFA revealed significant differences between EHEC and the Nino C strain, suggesting the possibility of identifying and discriminating the pathogenic strain from commonly occurring environmental strains. EHEC strongly resembled the two K-12 strains, in particular, HF4714, making discrimination between these strains difficult. DFA was also used to analyze spectra from two of the nonpathogenic strains cultured in different media: on a trypticase soy (TS) agar plate and in a liquid TS broth. Strains cultured in different media were identified and effectively discriminated, being more similar than different strains cultured in identical media. All bacteria spectra were completely distinct from spectra obtained from the nutrient medium or ablation substrate alone. The ability to differentiate strains prepared and tested in different environments indicates that matrix effects and background contaminations do not necessarily preclude the use of LIBS to identify bacteria found in a variety of environments or grown under different conditions.
Enhancement of the room temperature luminescence of InAs quantum dots by GaSb capping
Authors: Ripalda J. M. , Alonso-Álvarez D. , Alén B. , Taboada A. G. , García J. M. , González Y. , González L.
Published: July 2007

The authors have studied the use of antimony for the optimization of the InAs∕GaAs(001) self-assembled quantum dot (QD) luminescence characteristics in the 1.3μm spectral region. The best results have been obtained by capping InAs QDs with 2 ML of GaSb grown on top of a 3 ML GaAs barrier separating the InAs and the GaSb layers. This results in an order of magnitude enhancement of the room temperature luminescence intensity at 1.3μm emission wavelength.
Local strain-induced 90° domain switching in a barium titanate single crystal
Authors: Park J.-H. , Park J. , Lee K.-B. , Koo T.-Y. , Youn H. S. , Ko Y. D. , Chung J.-S. , Hwang J. Y. , Jeong S.-Y.
Published: July 2007

Local strain analysis for a BaTiO3 single crystal under electric loads was conducted using x-ray microdiffraction technique. During the polarization reversal, local 90° domain switchings were observed at certain positions instead of uniform 180° domain switching. Field-dependent strain analysis demonstrated that inhomogeneous domain switching was strongly related to local strain distributions. The results can be understood in terms of competition between elastic and electrostatic energies and provide a crystallographic evidence for the role of local strains on 90° domain switching.
Fabrication of low loss Ge33As12Se55 (AMTIR-1) planar waveguides
Authors: Choi Duk-Yong , Madden Steve , Rode Andrei , Wang Rongping , Luther-Davies Barry
Published: July 2007

The authors describe the fabrication of low loss Ge33As12Se55 rib waveguides. Pulsed laser deposition was used to obtain high quality, dense films with the same stoichiometry as the bulk glass, while standard semiconductor processing was used to pattern the waveguides. They obtained rib waveguides of 3, 4, and 5μm wide with propagation losses (0.3dB∕cm at 1550nm) more than ten times lower than previously reported for this material.
p
H
sensor using AlGaN∕GaN high electron mobility transistors with Sc2O3 in the gate region
Authors: Kang B. S. , Wang H. T. , Ren F. , Gila B. P. , Abernathy C. R. , Pearton S. J. , Johnson J. W. , Rajagopal P. , Roberts J. C. , Piner E. L. , Linthicum K. J.
Published: July 2007

Ungated AlGaN∕GaN high electron mobility transistors (HEMTs) exhibit large changes in current upon exposing the gate region to polar liquids. The polar nature of the electrolyte introduced leds to a change of surface charges, producing a change in surface potential at the semiconductor/liquid interface. The use of Sc2O3 gate dielectric produced superior results to either a native oxide or UV ozone-induced oxide in the gate region. The ungated HEMTs with Sc2O3 in the gate region exhibited a linear change in current between pH 3 and 10 of 37μA∕pH. The HEMT pH sensors show stable operation with a resolution of <0.1pH over the entire pH range. The results indicate that the HEMTs may have application in monitoring pH solution changes between 7 and 8, the range of interest for testing human blood.
DNA transformation via local heat shock
Authors: Li Sha , Meadow Anderson L. , Yang Jui-Ming , Lin Liwei , Yang Haw
Published: July 2007

This work describes transformation of foreign DNA into bacterial host cells by local heat shock using a microfluidic system with on-chip, built-in platinum heaters. Plasmid DNA encoding ampicillin resistance and a fluorescent protein can be effectively transformed into the DH5α chemically competent E. coli using this device. Results further demonstrate that only one-thousandth of volume is required to obtain transformation efficiencies as good as or better than conventional practices. As such, this work complements other lab-on-a-chip technologies for potential gene cloning/therapy and protein expression applications.
Exploring lignification in conifers by silencing hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase in
Pinus radiata
Authors: Wagner Armin , Ralph John , Akiyama Takuya , Flint Heather , Phillips Lorelle , Torr Kirk , Nanayakkara Bernadette , Te Kiri Lana
Published: July 2007

The enzyme hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT) is involved in the production of methoxylated monolignols that are precursors to guaiacyl and syringyl lignin in angiosperm species. We identified and cloned a putative
HCT
gene from
Pinus radiata
, a coniferous gymnosperm that does not produce syringyl lignin. This gene was up-regulated during tracheary element (TE) formation in
P. radiata
cell cultures and showed 72.6% identity to the amino acid sequence of the
Nicotiana tabacum HCT
isolated earlier. RNAi-mediated silencing of the putative
HCT
gene had a strong impact on lignin content, monolignol composition, and interunit linkage distribution. AcBr assays revealed an up to 42% reduction in lignin content in TEs. Pyrolysis-GC/MS, thioacidolysis, and NMR detected substantial changes in lignin composition. Most notable was the rise of
p
-hydroxyphenyl units released by thioacidolysis, which increased from trace amounts in WT controls to up to 31% in transgenics. Two-dimensional
13
C-
1
H correlative NMR confirmed the increase in
p
-hydroxyphenyl units in the transgenics and revealed structural differences, including an increase in resinols, a reduction in dibenzodioxocins, and the presence of glycerol end groups. The observed modifications in silenced transgenics validate the targeted gene as being associated with lignin biosynthesis in
P. radiata
and thus likely to encode HCT. This enzyme therefore represents the metabolic entry point leading to the biosynthesis of methoxylated phenylpropanoids in angiosperm species and coniferous gymnosperms such as
P. radiata
.
A connector of two-component regulatory systems promotes signal amplification and persistence of expression
Authors: Kato Akinori , Mitrophanov Alexander Y. , Groisman Eduardo A.
Published: July 2007

Organisms rely on a variety of regulatory architectures to control gene transcription. Whereas the functional characteristics of particular architectures are well understood, the properties of newly discovered regulatory designs cannot be easily predicted. One emerging design depends on small proteins that connect two-component regulatory systems, which constitute the dominant form of bacterial signal transduction. These connectors enable one system to respond to the signal perceived by a different system. To understand the functional properties of such connector-mediated architectures, we investigated the pathway controlled by the PhoP-dependent connector protein PmrD of
Salmonella enterica
and contrasted it to the circuit in which genes are regulated directly by the transcription factor PhoP. The PmrD-mediated pathway displayed both signal amplification and persistence of expression when compared with the direct pathway. Mathematical modeling of the two pathways allowed us to identify critical factors responsible for signal amplification.
Antithrombogenic property of bone marrow mesenchymal stem cells in nanofibrous vascular grafts
Authors: Hashi Craig K. , Zhu Yiqian , Yang Guo-Yuan , Young William L. , Hsiao Benjamin S. , Wang Karin , Chu Benjamin , Li Song
Published: July 2007

Nanostructured biomaterials have tremendous potential for tissue engineering. However, the performance and integration of the nanomaterials
in vivo
are not well understood. A challenge in vascular tissue engineering is to develop optimal scaffolds and establish expandable cell sources for the construction of tissue-engineered vascular grafts that are nonthrombogenic and have long-term patency. Here, we used tissue-engineered vascular grafts as a model to demonstrate the potential of combining nanofibrous scaffolds and bone marrow mesenchymal stem cells (MSCs) for vascular tissue engineering. Biodegradable nanofibrous scaffolds with aligned nanofibers were used to mimic native collagen fibrils to guide cell organization in vascular grafts. The results from artery bypass experiments showed that nanofibrous scaffolds allowed efficient infiltration of vascular cells and matrix remodeling. Acellular grafts (without MSCs) resulted in significant intimal thickening, whereas cellular grafts (with MSCs) had excellent long-term patency and exhibited well organized layers of endothelial cells (ECs) and smooth muscle cells (SMCs), as in native arteries. Short-term experiments showed that nanofibrous scaffolds alone induced platelet adhesion and thrombus formation, which was suppressed by MSC seeding. In addition, MSCs, as ECs, resisted platelet adhesion
in vitro
, which depended on cell-surface heparan sulfate proteoglycans. These data, together with the observation on the short-term engraftment of MSCs, suggest that the long-term patency of cellular grafts may be attributed to the antithrombogenic property of MSCs. These results demonstrate several favorable characteristics of nanofibrous scaffolds, the excellent patency of small-diameter nanofibrous vascular grafts, and the unique antithrombogenic property of MSCs.
Mostafa Sho‘aiyan: The Maverick Theorist of Revolution and the Failure of Frontal Politics in Iran
Authors: Vahabzadeh Peyman
Published: July 2007

Based on the author's original research, the paper will offer a glimpse into the frontal theory of Mostafa Sho‘aiyan. The paper draws on his life and experience of the National Front in the 1950s as a model for political thought. Next, the paper will show how he tried, through his unique and uncanonical revolutionary theory, to make a revolutionary praxis compatible with frontal thinking. Analytically, Sho‘aiyan's work proves that an ideologically driven concept of national liberation becomes an impediment for frontal politics in a truly democratic way. Sho‘aiyan's works represent a theoretical and existential response to the national liberation dilemma which the Iranian Marxists faced in the 1960s and 70s.
Changes In Speech Production In An Early Deafened Adult With A Cochlear Implant
Authors: Wong Patrick C. M.
Published: July 2007

Background and Aims: The current study is a first investigation reporting the speech production characteristics of an early deafened adult cochlear implant user after a course of speech–language treatment.

Methods and Procedures: The participant is culturally deaf and received the cochlear implant when she was 43 years old. A 24‐week ABCABC single‐subject treatment programme was conducted addressing articulation, the oral production of printed words, and voice production, with two 4‐week segments for each area.

Outcomes and Results: Treatment‐specific progress, revealed by untrained stimuli, was made in areas of articulation and oral production of printed words, but not voice production. Formal measures also confirmed the patient's progress.

Conclusions: These results were discussed in relation to how long‐term reduction of general auditory input and under‐use of the speech production mechanisms can be remediated by technological and behavioural treatment.
Managing South Africa's trawl bycatch
Authors: Walmsley Sarah A. , Leslie Rob W. , Sauer Warwick H. H.
Published: July 2007

Walmsley, S. A., Leslie, R. W., and Sauer, W. H. H. 2007. Managing South Africa's trawl bycatch. – ICES Journal of Marine Science, 64: 405–412. Over the past few decades, it has become widely recognized that the management strategies of world fisheries must ensure sustainability of bycatch as well as of target species. South Africa implemented a pilot observer programme from 1995 to 2000 to collect data on the levels and patterns of bycatch and discards in the demersal trawl fishery. Here, the results of that programme are used in conjunction with information on bycatch value and compliance to assess the issues and problems regarding bycatch and discarding in the fishery. In general, bycatch components can be placed into one of three categories (discarded bycatch, retained bycatch, and processing waste), each of which present different management problems and require different management approaches. The results were used to formulate a bycatch management plan for the demersal trawl fishery in South Africa. Given the need to continue monitoring bycatch, the performance of the pilot observer programme is reviewed, and the levels of sampling effort required for a national programme are discussed.
Differences in risks and consequences of salmon louse, Lepeophtheirus salmonis (Krøyer), infestation on sympatric populations of Atlantic salmon, brown trout, and Arctic charr within northern fjords
Authors: Bjørn P. A. , Finstad B. , Kristoffersen R. , McKinley R. S. , Rikardsen A. H.
Published: July 2007

Bjørn, P-A., Finstad, B., Kristoffersen, R., Rikardsen, A. H., and McKinley, R. S. 2007. Differences in risks and consequences of salmon louse, Lepeophtheirus salmonis (Krøyer), infestation on sympatric populations of Atlantic salmon, brown trout, and Arctic charr within northern fjords. – ICES Journal of Marine Science, 64: 386–393. Differences in salmon louse (Lepeophtheirus salmonis) infestation on sympatric populations of fjord-migrating, Atlantic salmon post-smolts (Salmo salar), brown trout (Salmo trutta) (sea trout), and Arctic charr (Salvelinus alpinus) were studied in three fjords with fish-farming activity in northern Norway during the period June–August 2000. Atlantic salmon post-smolts were only captured in the fjords during late June and early July, and probably left them subsequently. No fish were infested with salmon lice. In contrast, brown trout and Arctic charr had similar infection patterns during their sampling periods, with very low prevalence and mean infection intensity during June (0–21% and 0–6 lice per fish, respectively), slightly increasing in July (8–70% and 6–12 lice per fish, respectively), and peaking in August (80–88% and 19–27 lice per fish, respectively). The chalimus stages dominated during June and July, with a few pre-adult and adult stages observed in July, and all stages were found frequently during August. The observations indicate that Atlantic salmon may have a mismatch between the time of louse infestation and their post-smolt fjord migration in northern fjords. In contrast, brown trout and Arctic charr feed within the fjords throughout summer and have a higher risk of harmful infestation in years with suitable environmental conditions for salmon louse development, especially in fish‐farming areas. Arctic charr usually spend the shortest time at sea of the three species, and the salmon lice may not have time to develop to the adult stage on this species.
Application and validation of otolith microstructure as a stock identification method in mixed Atlantic herring (Clupea harengus) stocks in the North Sea and western Baltic
Authors: Clausen L. A. W. , Bekkevold D. , Hatfield E. M. C. , Mosegaard H.
Published: July 2007

Clausen, L. A. W., Bekkevold, D., Hatifield, E. M. C., and Mosegard, H. 2007. Application and validation of otolith microstructure as a stock identification method in mixed Atlantic herring (Clupea harengus) stocks in the North Sea and western Baltic. – ICES Journal of Marine Science, 64: 377–385. Herring (Clupea harengus) populations with different spawning times mix in ICES Division IIIa. For stock assessment, otolith microstructure analysis is used to determine the hatching season of individuals, classifying them into hatch type spring, autumn, or winter. The currently applied method uses visual inspection of season-specific daily increment pattern for the larval period. With this method, variability in individual microstructure and a lack of correspondence between hatch and spawning time may lead to classification error. We validate the visual inspection procedure in relation to these potential sources of error. Otoliths from spawning herring were first classified blindly and the results compared with spawning season. In all, 91% of classifications corresponded, and errors represented misclassifications mainly between autumn and winter spawners. However, the estimates may be biased if hatch and spawning times differ, and an objective method of hatch-time estimation based on linear modelling was employed, enumerating unbroken series of daily increments in 0-group herring hatched in different seasons. Visual inspection and objective estimation agreed in 89% of cases, and most of the errors were explained by overlapping hatch periods. Results show that herring older than the 0-group can be classified using multiple linear regression of hatch time on median increment width.
Generalized compensation in stock-recruit functions: properties and implications for management
Authors: Brooks Elizabeth N. , Powers Joseph E.
Published: July 2007

Brooks, E. N., and Powers, J. E. 2007. Generalized compensation in stock-recruit functions: properties and implications for management. – ICES Journal of Marine Science, 64: 413–424. A general stock-recruit function that explicitly defines density-dependent and -independent components of mortality over multiple stages is derived. By generalizing the stock-recruit function and the timing of density-dependent compensation, the impacts of different sources and magnitudes of mortality during the recruitment phase can be evaluated. Given reasonably comparable stage durations, compensation in early stages of a multistage process dominates density-independent effects; in later stages, density-dependent and -independent factors compete on a more even scale. Ratios of equilibrium statistics associated with the stock-recruit function under alternative compensation timing scenarios can be determined from the ratio of the compensation terms in the models when all scenarios assume the same type of stock-recruit function (Ricker or Beverton–Holt). This analytical result facilitates evaluation of proposed impacts or rehabilitation strategies without the need for a full stock assessment. Exogenous mortality has more impact on the maximum excess recruitment if that rate occurs later in the recruitment interval, especially if it takes place after compensation. Reparameterizing this generalized stock-recruit function in terms of steepness and virgin recruitment, we show that steepness is not influenced by the timing of compensation nor by the length of the recruitment interval; the level of virgin recruitment, however, is affected by both.
Fisheries management and institutional reform: a European perspective
Authors: Symes David
Published: July 2007

Symes, D. 2007. Fisheries management and institutional reform: a European perspective. – ICES Journal of Marine Science, 64: 779–785.

Changes to the institutional frameworks that help shape fisheries policy-making are typically incremental and piecemeal, with governments content to tinker at the edges, but rarely willing to embrace fundamental reform. The present study outlines the nature of institutional frameworks and explores the need to ensure coherence across different scales of governance. Co-management and participative governance are commonly regarded as important recent developments. Although they may well satisfy notions of “good governance”, their ability to deliver better policy, more effective management, and sustainable fisheries is open to question. In the search to improve the efficacy of fisheries management, three key issues are identified: restructuring of co-management organizations, clarification of property rights, and development of an ecosystem-based approach. Finally, attention is drawn to the challenge to fisheries governance posed by moves towards integrated management.
The weakening role of science in the management of groundfish off the east coast of Canada
Authors: Shelton Peter A.
Published: July 2007

Shelton, P. A. 2007. The weakening role of science in the management of groundfish off the east coast of Canada. – ICES Journal of Marine Science, 64: 723–729. The link between science and decision-making for groundfish fisheries off Canada's east coast has weakened during the past two decades. The demand for a large degree of flexibility in the decision-making process by both the Department of Fisheries and Oceans and the Northwest Atlantic Fisheries Organization, as well as the perceived low credibility of scientific knowledge, has resulted in an underutilization of science capacity to provide risk-based assessments and to evaluate management strategies for robustness to uncertainty and compliance with the precautionary approach. The transition from science-based to ad hoc fisheries management is described, and the potential impact of two new approaches, ecosystem-based fisheries management and shared stewardship, is considered.