bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructural Evolution in a CeO2-Gd2O3 System
Authors: Ye Fei , Ou Ding Rong , Mori Toshiyuki
Published: December 2011

Microstructural evolution in a CeO2-Gd2O3 system at atomic and nanoscale levels with increasing Gd concentration has been comprehensively investigated by transmission electron microscopy. When the Gd concentration was increased from 10 to 80 at.%, the phase transformation from ceria with fluorite structure to solid solution with C-type structure was not a sudden change but an evolution in the sequence of clusters, domains, and precipitates with C-type structure in the fluorite-structured matrix. Moreover, the ordering of aggregated Gd cations and oxygen vacancies in these microstructural inhomogeneities developed continuously with increasing Gd concentration. This microstructural evolution can be further described based on the development of defect clusters containing Gd cations and oxygen vacancies.
Implementing successful residential alternatives to acute in-patient psychiatric services: lessons from a multi-centre study of alternatives in England
Authors: Morant N. , Lloyd-Evans B. , Gilburt H. , Slade M. , Osborn D. , Johnson S.
Published: December 2011

Background.

Standard acute psychiatric care in the UK is costly but problematic. Alternatives to standard in-patient wards exist, but little is known about their effectiveness, implementation and sustainability. This paper explores successful features and limitations of five residential alternative services in England and factors that facilitate or impede their initial and sustained implementation and success.

Methods.

Semi-structured interviews about the functioning of six alternative services were conducted with 36 mental health professionals with good working knowledge of, and various connections with these services. A group interview with study researchers was also conducted. Data were analysed using thematic analysis.

Results.

One service did not show evidence of operating as an alternative and was excluded from further analysis. The remaining five alternatives are valued for providing a more holistic style of care than standard services that confers many perceived benefits. However, they are seen as less appropriate for compulsorily detained or highly disturbed patients, and as providing less comprehensive treatment packages than hospital settings. Factors identified as important to successful implementation and sustainability are: responding to known shortcomings in local acute care systems; balancing role clarity and adaptability; integration with other services; and awareness of the alternative among relevant local health-care providers.

Conclusions.

Residential alternatives can play an important role in managing mental health crises. Their successful implementation and endurance depend on establishing and maintaining a valued position within local service systems. Findings contribute to bridging the gap between research evidence on the problems of standard acute care and delivering improved crisis management services.
Eddy effects on sea surface temperature and sea surface wind in the continental slope region of the northern South China Sea
Authors: Chow Chun Hoe , Liu Qinyu
Published: December 2011

Warm and cold sea surface temperature (SST) tongues on weather timescales are detected in the continental slope region of the northern South China Sea (NSCS), and their effects on sea surface wind are studied, using satellite observations. Crossing the basin‐scale SST front, geostrophic currents between cyclonic and anticyclonic eddies induce the warm and cold SST tongues during the northeast monsoon. Corresponding to the warm and cold SST tongues, the sea surface wind is highly uneven in spatial distribution. Its speed is faster (slower) over the warm (cold) SST tongues than the surrounding areas. The SST and sea surface wind non‐uniformity, in space, shifts southwestward with eddy motion, along the continental slope. These new findings from satellite observations give us an opportunity to study oceanic eddy's roles in ocean‐atmosphere interaction on weather timescales.
Reduced upper ocean turbulence and changes to bubble size distributions during large downward heat flux events
Authors: Vagle Svein , Gemmrich Johannes , Czerski Helen
Published: December 2011

During the Radiance in a Dynamic Ocean (RaDyO) field study south of Hawaii in September 2009, simultaneous observations of total heat flux, upper ocean turbulence, and bubble size distributions suggest that large downward heat flux modulates the upper ocean turbulence dissipation rates and subsequently the upper ocean bubble field. The observations show that the turbulence dissipation rates near the ocean surface are reduced by a factor of 10 during periods with high downward heat flux (>400 W m−2). Simultaneously, the observations of bubble size distributions at a depth of 0.5 m show that there were significantly lower concentrations of bubbles with radii >100 μm than during a winter study in the Gulf of Mexico. Also, the number of bubbles with radii >200 μm is found to be dependent on the heat flux, with fewer such bubbles during stable (positive heat flux) conditions. The reduced number of larger bubbles reduces the effect of the bubble field on optical reflectance by up to a factor of 3 compared to other locations at similar wind speeds.
High‐resolution sea surface reconstructions off Cape Hatteras over the last 10 ka
Authors: Cléroux Caroline , Debret Maxime , Cortijo Elsa , Duplessy Jean‐Claude , Dewilde Fabien , Reijmer John , Massei Nicolas
Published: December 2011

This study presents high‐resolution foraminiferal‐based sea surface temperature, sea surface salinity and upper water column stratification reconstructions off Cape Hatteras, a region sensitive to atmospheric and thermohaline circulation changes associated with the Gulf Stream. We focus on the last 10,000 years (10 ka) to study the surface hydrology changes under our current climate conditions and discuss the centennial to millennial time scale variability. We observed opposite evolutions between the conditions off Cape Hatteras and those south of Iceland, known today for the North Atlantic Oscillation pattern. We interpret the temperature and salinity changes in both regions as co‐variation of activities of the subtropical and subpolar gyres. Around 8.3 ka and 5.2–3.5 ka, positive salinity anomalies are reconstructed off Cape Hatteras. We demonstrate, for the 5.2–3.5 ka period, that the salinity increase was caused by the cessation of the low salinity surface flow coming from the north. A northward displacement of the Gulf Stream, blocking the southbound low‐salinity flow, concomitant to a reduced Meridional Overturning Circulation is the most likely scenario. Finally, wavelet transform analysis revealed a 1000‐year period pacing the δ18O signal over the early Holocene. This 1000‐year frequency band is significantly coherent with the 1000‐year frequency band of Total Solar Irradiance (TSI) between 9.5 ka and 7 ka and both signals are in phase over the rest of the studied period.
The fourth‐generation Water Vapor Millimeter‐Wave Spectrometer
Authors: Gomez R. Michael , Nedoluha Gerald E. , Neal Helen L. , McDermid I. Stuart
Published: December 2011

For 20 years the Naval Research Laboratory has been making continuous water vapor profile measurements at 22.235 GHz with the Water Vapor Millimeter‐Wave Spectrometer (WVMS) instruments, with the program expanding from one to three instruments in the first 6 years. Since the initial deployments there have been gradual improvements in the instrument design which have improved data quality and reduced maintenance requirements. Recent technological developments have made it possible to entirely redesign the instrument and improve not only the quality of the measurements but also the capability of the instrument. We present the fourth‐generation instrument now operating at Table Mountain, California, which incorporates the most recent advances in microwave radiometry. This instrument represents the most significant extension of our measurement capability to date, enabling us to measure middle atmospheric water vapor from ∼26–80 km.
An ecohydrological approach to predicting hillslope‐scale vegetation patterns in dryland ecosystems
Authors: Franz Trenton E. , Caylor Kelly K. , King Elizabeth G. , Nordbotten Jan M. , Celia Michael A. , Rodríguez‐Iturbe Ignacio
Published: December 2011

Drylands are an important ecosystem, as they cover over 40% of the Earth's land surface and are believed to be sensitive to climate change. Where dryland vegetation supports pastoralist livestock production, catastrophic ecological shifts present a grave concern because of the direct coupling between the quality of available forage and human livelihoods. In this research we investigate the organization of vegetation on hillslopes by developing a relatively simple spatially explicit daily stochastic ecohydrological model. Using a 2 year observational study in central Kenya, we present an empirical patch water balance of three representative patch types, bare soil, grass, and tree. Given the recent expansion of bare areas, the system is dominated by Hortonian runoff and overland flow. By incorporating concepts of simple local interactions from complex systems we are able to simulate a range of surface flowpath convergence states across the hillslope during a rain event. The model also allows the root to canopy radius of the tree patches to vary affecting the length scale of water competition. By changing the length scales of facilitation and competition, the model demonstrates a range of most efficient hillslope water‐use patterns from random to highly organized static vegetation patterns. The findings of this work support the mechanism of symmetry‐breaking instabilities for pattern formation in drylands.
The Inter-Valley Soil Comparative Survey: the ecology of Dry Valley edaphic microbial communities
Authors: Lee Charles K , Barbier Béatrice A , Bottos Eric M , McDonald Ian R , Cary Stephen Craig
Published: December 2011

Recent applications of molecular genetics to edaphic microbial communities of the McMurdo Dry Valleys and elsewhere have rejected a long-held belief that Antarctic soils contain extremely limited microbial diversity. The Inter-Valley Soil Comparative Survey aims to elucidate the factors shaping these unique microbial communities and their biogeography by integrating molecular genetic approaches with biogeochemical analyses. Although the microbial communities of Dry Valley soils may be complex, there is little doubt that the ecosystem's food web is relatively simple, and evidence suggests that physicochemical conditions may have the dominant role in shaping microbial communities. To examine this hypothesis, bacterial communities from representative soil samples collected in four geographically disparate Dry Valleys were analyzed using molecular genetic tools, including pyrosequencing of 16S rRNA gene PCR amplicons. Results show that the four communities are structurally and phylogenetically distinct, and possess significantly different levels of diversity. Strikingly, only 2 of 214 phylotypes were found in all four valleys, challenging a widespread assumption that the microbiota of the Dry Valleys is composed of a few cosmopolitan species. Analysis of soil geochemical properties indicated that salt content, alongside altitude and Cu2+, was significantly correlated with differences in microbial communities. Our results indicate that the microbial ecology of Dry Valley soils is highly localized and that physicochemical factors potentially have major roles in shaping the microbiology of ice-free areas of Antarctica. These findings hint at links between Dry Valley glacial geomorphology and microbial ecology, and raise previously unrecognized issues related to environmental management of this unique ecosystem.
Insights into the PX (phox-homology) domain and SNX (sorting nexin) protein families: structures, functions and roles in disease
Authors: Teasdale Rohan D. , Collins Brett M.
Published: December 2011

The mammalian genome encodes 49 proteins that possess a PX (phox-homology) domain, responsible for membrane attachment to organelles of the secretory and endocytic system via binding of phosphoinositide lipids. The PX domain proteins, most of which are classified as SNXs (sorting nexins), constitute an extremely diverse family of molecules that play varied roles in membrane trafficking, cell signalling, membrane remodelling and organelle motility. In the present review, we present an overview of the family, incorporating recent functional and structural insights, and propose an updated classification of the proteins into distinct subfamilies on the basis of these insights. Almost all PX domain proteins bind PtdIns3P and are recruited to early endosomal membranes. Although other specificities and localizations have been reported for a select few family members, the molecular basis for binding to other lipids is still not clear. The PX domain is also emerging as an important protein–protein interaction domain, binding endocytic and exocytic machinery, transmembrane proteins and many other molecules. A comprehensive survey of the molecular interactions governed by PX proteins highlights the functional diversity of the family as trafficking cargo adaptors and membrane-associated scaffolds regulating cell signalling. Finally, we examine the mounting evidence linking PX proteins to different disorders, in particular focusing on their emerging importance in both pathogen invasion and amyloid production in Alzheimer's disease.
IκB kinase β (IKKβ) does not mediate feedback inhibition of the insulin signalling cascade
Authors: Lancaster Graeme I. , Skiba Beata , Yang Christine , Nicholls Hayley T. , Langley Katherine G. , Chan M. H. Stanley , Bruce Clinton R. , Rewcastle Gordon W. , Shepherd Peter R. , Karin Michael , Febbraio Mark A.
Published: December 2011

In the present study, we have examined whether IKKβ [IκB (inhibitor of nuclear factor κB) kinase β] plays a role in feedback inhibition of the insulin signalling cascade. Insulin induces the phosphorylation of IKKβ, in vitro and in vivo, and this effect is dependent on intact signalling via PI3K (phosphoinositide 3-kinase), but not PKB (protein kinase B). To test the hypothesis that insulin activates IKKβ as a means of negative feedback, we employed a variety of experimental approaches. First, pharmacological inhibition of IKKβ via BMS-345541 did not potentiate insulin-induced IRS1 (insulin receptor substrate 1) tyrosine phosphorylation, PKB phosphorylation or 2-deoxyglucose uptake in differentiated 3T3-L1 adipocytes. BMS-345541 did not prevent insulin-induced IRS1 serine phosphorylation on known IKKβ target sites. Secondly, adenovirus-mediated overexpression of wild-type IKKβ in differentiated 3T3-L1 adipocytes did not suppress insulin-stimulated 2-deoxyglucose uptake, IRS1 tyrosine phosphorylation, IRS1 association with the p85 regulatory subunit of PI3K or PKB phosphorylation. Thirdly, insulin signalling was not potentiated in mouse embryonic fibroblasts lacking IKKβ. Finally, insulin treatment of 3T3-L1 adipocytes did not promote the recruitment of IKKβ to IRS1, supporting our findings that IKKβ, although activated by insulin, does not promote direct serine phosphorylation of IRS1 and does not contribute to the feedback inhibition of the insulin signalling cascade.
On the solvation structure of dimethylsulfoxide/water around the phosphatidylcholine head group in solution
Authors: Dabkowska Aleksandra P. , Foglia Fabrizia , Lawrence M. Jayne , Lorenz Christian D. , McLain Sylvia E.
Published: December 2011

The solution structure of the phosphocholine (PC) head group in 1,2-dipropionyl-sn-glycero-3-phosphocholine (C3-PC) in 30 mol. % dimethylsulfoxide (DMSO)-water solutions has been determined by using neutron diffraction enhanced with isotopic substitution in combination with computer simulation techniques. By investigating the atomic scale hydration structure around the PC head group, a unique description of the displacement of water molecules by DMSO molecules is detailed around various locations of the head group. Specifically, DMSO molecules were found to be the most prevalent around the onium portion of the head group, with the dipoles of the DMSO molecules being aligned where the negatively charged oxygen can interact strongly with the positively charged lipid group. The phosphate group is also partially dehydrated by the presence of the DMSO molecules. However, around this group the bulkier positive end of the DMSO dipole is interacting with negatively charged groups of the lipid head group, the DMSO layer shows no obvious ordering as it cannot form hydrogen bonds with the oxygen atoms in the PO4 group such as water molecules can. Interestingly, DMSO-water contacts have also increased in the presence of the lipid molecule relative to DMSO-water contacts observed in pure DMSO/water solutions at similar concentrations.
A magnetically driven reciprocating probe for tokamak scrape-off layer measurements
Authors: Gunn J. P. , Pascal J.-Y.
Published: December 2011

A new in situ reciprocating probe system has been developed to provide scrape-off layer measurements in the Tore Supra tokamak. The probe motion is provided by the rotation of an energized coil in the tokamak magnetic field. Simple analytic approximations to the exact numerical model were used to identify the important parameters that govern the dynamics of the system, and optimize the coil geometry, the electrical circuit, and the stiffness of the retaining spring. The linear speed of the probe is directly proportional to the current induced by the coil's rotation; its integral gives the coil position, providing a means to implement real-time feedback control of the probe motion. Two probes were recently mounted on a movable outboard antenna protection limiter in Tore Supra and provided automatic measurements during the 2011 experimental campaign.
The inner structure of collisionless magnetic reconnection: The electron-frame dissipation measure and Hall fields
Authors: Zenitani Seiji , Hesse Michael , Klimas Alex , Black Carrie , Kuznetsova Masha
Published: December 2011

It was recently proposed that the electron-frame dissipation measure, the energy transfer from the electromagnetic field to plasmas in the electron’s rest frame, identifies the dissipation region of collisionless magnetic reconnection [Zenitani et al., Phys. Rev. Lett. 106, 195003 (2011)]. The measure is further applied to the electron-scale structures of antiparallel reconnection, by using two-dimensional particle-in-cell simulations. The size of the central dissipation region is controlled by the electron-ion mass ratio, suggesting that electron physics is essential. A narrow electron jet extends along the outflow direction until it reaches an electron shock. The jet region appears to be anti-dissipative. At the shock, electron heating is relevant to a magnetic cavity signature. The results are summarized to a unified picture of the single dissipation region in a Hall magnetic geometry.
A flexible model for water based on TIP4P/2005
Authors: González Miguel A. , Abascal José L. F.
Published: December 2011

A new flexible water model, TIP4P/2005f, is developed. The idea was to add intramolecular degrees of freedom to the successful rigid model TIP4P/2005 in order to try to improve the predictions for some properties, and to enable the calculation of new ones. The new model incorporates flexibility by means of a Morse potential for the bond stretching and a harmonic term for the angle bending. The parameters have been fitted to account for the peaks of the infrared spectrum of liquid water and to produce an averaged geometry close to that of TIP4P/2005. As for the intermolecular interactions, only a small change in the σ parameter of the Lennard-Jones potential has been introduced. The overall predictions are very close to those of TIP4P/2005. This ensures that the new model may be used with the same confidence as its predecessor in studies where a flexible model is advisable.
Drift velocity peak and negative differential mobility in high field transport in graphene nanoribbons explained by numerical simulations
Authors: Betti A. , Fiori G. , Iannaccone G.
Published: December 2011

We present numerical simulations of high field transport in both suspended and deposited armchair graphene nanoribbon (A-GNR) on HfO2 substrate. Drift velocity in suspended GNR does not saturate at high electric field (F), but rather decreases, showing a maximum for F ≈ 10 kV/cm. Deposition on HfO2 strongly degrades the drift velocity by up to a factor ≈10 with respect to suspended GNRs in the low-field regime, whereas at high fields, drift velocity approaches the intrinsic value expected in suspended GNRs. Even in the assumption of perfect edges, the obtained mobility is far behind what expected in two-dimensional graphene, and is further reduced by surface optical phonons.
Ultra-flat coplanar electrodes for controlled electrical contact of molecular films
Authors: Martin Florent , Hendriksen Bas , Katan Allard , Ratera Imma , Qi Yabing , Harteneck Bruce , Liddle J. Alexander , Salmeron Miquel
Published: December 2011

Reliable measurement of electrical charge transport in molecular layers is a delicate task that requires establishing contacts with electrodes without perturbing the molecular structure of the film. We show how this can be achieved by means of novel device consisting of ultra-flat electrodes separated by insulating material to support the molecular film. We show the fabrication process of these electrodes using a replica technique where gold electrodes are embedded in a silicon oxide film deposited on the angstrom-level flat surface of a silicon wafer. Importantly, the co-planarity of the electrode and oxide areas of the substrate was in the sub-nanometer range. We illustrate the capabilities of the system by mapping the distribution of electrical transport pathways in molecular thin films of self-assembled oligothiophene derivatives using conductive atomic force microscopy. In comparison with traditional bottom contact non-coplanar electrodes, the films deposited on our electrodes exhibited contact resistances lower by a factor of 40 than that of the similar but non-coplanar electrodes.
Laser guiding plasma channel formation criterion in highly relativistic regime
Authors: Gu Y. J. , Zhu Z. , Kong Q. , Li Y. Y. , Li X. F. , Chen C. Y. , Kawata S.
Published: December 2011

Self-formed plasma channels induced by ultra-intense and ultra-short laser pulses have been investigated with 2.5-dimensional particle-in-cell simulations. A criterion of channel formation under the highly relativistic regime is proposed and tested by simulation results. Good matches between criterion predictions and simulations are found in most cases, but small deviations occur when the plasma density is very low or near critical. The possibility of generating a channel by a femtosecond pulsed laser is also discussed.
Extended x-ray absorption fine structure study of porous GaSb formed by ion implantation
Authors: Kluth P. , Kluth S. M. , Johannessen B. , Glover C. J. , Foran G. J. , Ridgway M. C.
Published: December 2011

Porous GaSb has been formed by Ga ion implantation into crystalline GaSb substrates at either room temperature or −180 °C. The morphology has been characterized using scanning electron microscopy and the atomic structure was determined using extended x-ray absorption fine structure spectroscopy. Room-temperature implantation at low fluences leads to the formation of ∼20-nm voids though the material remains crystalline. Higher fluences cause the microstructure to evolve into a network of amorphous GaSb rods ∼15 nm in diameter. In contrast, implantation at −180 °C generates large, elongated voids but no rods. Upon exposure to air, the surface of the porous material is readily oxidized yielding Ga2O3 and metallic Sb precipitates, the latter resulting from the reduction of unstable Sb2O3. We consider and discuss the atomic-scale mechanisms potentially operative during the concurrent crystalline-to-amorphous and continuous-to-porous transformations.
Competitive device performance of low-temperature and all-solution-processed metal-oxide thin-film transistors
Authors: Kim Kyung Min , Kim Chi Wan , Heo Jae-Seok , Na Hyungil , Lee Jung Eun , Park Chang Bum , Bae Jong-Uk , Kim Chang-Dong , Jun Myungchul , Hwang Yong Kee , Meyers Stephen T. , Grenville Andrew , Keszler Douglas A.
Published: December 2011

In this Letter, we described a solution-processed indium-gallium-zinc oxide thin-film transistors (TFTs) with a solution-processed aluminum oxide phosphate gate dielectric, fabricated at a maximum annealing temperature under 350 °C to be applicable to conventional fabrication process of flat-panel displays (FPDs). The solution-processed TFTs exhibited competitive device characteristics under 350 °C, including a field-effect mobility of 4.50 cm2/Vs, an on-to-off current ratio of ∼109, a threshold voltage of 2.34 V, and a subthreshold gate swing of 0.46 V/dec, making them applicable to the future backplane of FPDs.
Interaction of viscous and inviscid instability modes in separation–bubble transition
Authors: Brinkerhoff Joshua R. , Yaras Metin I.
Published: December 2011

This paper describes numerical simulations that are used to examine the interaction of viscous and inviscid instability modes in laminar-to-turbulent transition in a separation bubble. The results of a direct numerical simulation are presented in which separation of a laminar boundary-layer occurs in the presence of an adverse streamwise pressure gradient. The simulation is performed at low freestream-turbulence levels and at a flow Reynolds number and pressure distribution approximating those typically encountered on the suction side of low-pressure turbine blades in a gas-turbine engine. The simulation results reveal the development of a viscous instability upstream of the point of separation which produces streamwise-oriented vortices in the attached laminar boundary layer. These vortices remain embedded in the flow downstream of separation and are carried into the separated shear layer, where they are amplified by the local adverse pressure-gradient and contribute to the formation of coherent hairpin-like vortices. A strong interaction is observed between these vortices and the inviscid instability that typically dominates the shear layer in the separated zone. The interaction is noted to determine the spanwise extent of the vortical flow structures that periodically shed from the downstream end of the separated shear layer. The structure of the shed vortical flow structures is examined and compared with the coherent structures typically observed within turbulent boundary layers.
Detection limits in whispering gallery biosensors with plasmonic enhancement
Authors: Swaim Jon D. , Knittel Joachim , Bowen Warwick P.
Published: December 2011

We perform numerical modeling of a gold nanorod bound to the surface of a microtoroid-based biosensor. Localized surface plasmon resonances in the nanorod give rise to strong enhancements in the electric field when excited near resonance, increasing the frequency shift for a single bovine serum albumin molecule by a factor of 870, with even larger enhancements predicted for smaller proteins. On resonance, the frequency shift is predicted to be on the order of MHz, more than an order of magnitude larger than measurement noise arising from time-averaged frequency and thermal fluctuations.
Temperature-induced anomalous brittle-to-ductile transition of bulk metallic glasses
Authors: Pan D. , Guo H. , Zhang W. , Inoue A. , Chen M. W.
Published: December 2011

We report an anomalous brittle-to-ductile transition (BTDT) in Au-based bulk metallic glasses (BMGs). Despite of brittle failure without noticeable plastic strain under uniaxial compression at room temperature, the Au-based BMGs exhibit remarkable plasticity at cryogenic temperatures, which is opposite to the BTDT in crystalline materials. This anomalous transition originates from the strong temperature dependence of the fundamental deformation units, viz. shear transformation zones, giving rise to both superior plasticity and high strength of BMGs for low-temperature applications.
Ultra-short suspended single-wall carbon nanotube transistors
Authors: Island J. O. , Tayari V. , Yiğen S. , McRae A. C. , Champagne A. R.
Published: December 2011

We describe a method to fabricate clean suspended single-wall carbon nanotube (SWCNT) transistors hosting a single quantum dot ranging in length from a few 10 s of nm down to ≈3 nm. We first align narrow gold bow-tie junctions on top of individual SWCNTs and suspend the devices. We then use a feedback-controlled electromigration to break the gold junctions and expose nm-sized sections of SWCNTs. We measure electron transport in these devices at low temperature and show that they form clean and tunable single-electron transistors. These ultra-short suspended transistors offer the prospect of studying THz oscillators with strong electron-vibron coupling.
High transport critical current densities in textured Fe-sheathed Sr1−xKxFe2As2+Sn superconducting tapes
Authors: Gao Zhaoshun , Wang Lei , Yao Chao , Qi Yanpeng , Wang Chunlei , Zhang Xianping , Wang Dongliang , Wang Chengduo , Ma Yanwei
Published: December 2011

We report the realization of grain alignment in Sn-added Sr1−xKxFe2As2 superconducting tapes with Fe sheath prepared by ex-situ powder-in-tube method. At 4.2 K, high transport critical current densities Jc of 2.5 × 104 A/cm2 (Ic = 180 A) in self-field and 3.5 × 103 A/cm2 (Ic = 25.5 A) in 10 T have been measured. These values are the highest ever reported so far for Fe-based superconducting wires and tapes. We believe the superior Jc in our tape samples are due to well textured grains and strengthened intergrain coupling achieved by Sn addition. Our results demonstrated an encouraging prospect for application of iron based superconductors.
Maser Source-Finding Methods in HOPS
Authors: Walsh A. J. , Purcell C. , Longmore S. , Jordan C. H. , Lowe V.
Published: December 2011

The H2O Southern Galactic Plane Survey (HOPS) has observed 100 deg2 of the Galactic plane, using the Mopra radio telescope to search for emission from multiple spectral lines in the 12-mm band (19.5–27.5 GHz). Perhaps the most important of these spectral lines is the 22.2-GHz water-maser transition. We describe the methods used to identify water-maser candidates and subsequent confirmation of the sources. Our methods involve a simple determination of likely candidates by searching peak emission maps, utilising the intrinsic nature of water-maser emission, spatially unresolved and spectrally narrow-lined. We estimate completeness limits and compare our method with results from the duchamp source finder. We find that the two methods perform similarly. We conclude that the similarity in performance is due to the intrinsic limitation of the noise characteristics of the data. The advantages of our method are that it is slightly more efficient in eliminating spurious detections and is simple to implement. The disadvantage is that it is a manual method of finding sources and so is not practical on datasets much larger than HOPS, or for datasets with extended emission that needs to be characterised. We outline a two-stage method for the most efficient means of finding masers, using duchamp.
Structure-based design of conformation- and sequence-specific antibodies against amyloid β
Authors: Perchiacca Joseph M. , Ladiwala Ali Reza A. , Bhattacharya Moumita , Tessier Peter M.
Published: December 2011

Conformation-specific antibodies that recognize aggregated proteins associated with several conformational disorders (e.g., Parkinson and prion diseases) are invaluable for diagnostic and therapeutic applications. However, no systematic strategy exists for generating conformation-specific antibodies that target linear sequence epitopes within misfolded proteins. Here we report a strategy for designing conformation- and sequence-specific antibodies against misfolded proteins that is inspired by the molecular interactions governing protein aggregation. We find that grafting small amyloidogenic peptides (6–10 residues) from the Aβ42 peptide associated with Alzheimer’s disease into the complementarity determining regions of a domain (
V

H

) antibody generates antibody variants that recognize Aβ soluble oligomers and amyloid fibrils with nanomolar affinity. We refer to these antibodies as gammabodies for grafted amyloid-motif antibodies. Gammabodies displaying the central amyloidogenic Aβ motif (

) are reactive with Aβ fibrils, whereas those displaying the amyloidogenic C terminus (

) are reactive with Aβ fibrils and oligomers (and weakly reactive with Aβ monomers). Importantly, we find that the grafted motifs target the corresponding peptide segments within misfolded Aβ conformers. Aβ gammabodies fail to cross-react with other amyloidogenic proteins and scrambling their grafted sequences eliminates antibody reactivity. Finally, gammabodies that recognize Aβ soluble oligomers and fibrils also neutralize the toxicity of each Aβ conformer. We expect that our antibody design strategy is not limited to Aβ and can be used to readily generate gammabodies against other toxic misfolded proteins.
Immune recognition of tumor-associated mucin MUC1 is achieved by a fully synthetic aberrantly glycosylated MUC1 tripartite vaccine
Authors: Lakshminarayanan Vani , Thompson Pamela , Wolfert Margreet A. , Buskas Therese , Bradley Judy M. , Pathangey Latha B. , Madsen Cathy S. , Cohen Peter A. , Gendler Sandra J. , Boons Geert-Jan
Published: December 2011

The mucin MUC1 is typically aberrantly glycosylated by epithelial cancer cells manifested by truncatedO-linked saccharides. The resultant glycopeptide epitopes can bind cell surface major histocompatibility complex (MHC) molecules and are susceptible to recognition by cytotoxic T lymphocytes (CTLs), whereas aberrantly glycosylated MUC1 protein on the tumor cell surface can be bound by antibodies to mediate antibody-dependent cell-mediated cytotoxicity (ADCC). Efforts to elicit CTLs and IgG antibodies against cancer-expressed MUC1 have not been successful when nonglycosylated MUC1 sequences were used for vaccination, probably due to conformational dissimilarities. Immunizations with densely glycosylated MUC1 peptides have also been ineffective due to impaired susceptibility to antigen processing. Given the challenges to immuno-target tumor-associated MUC1, we have identified the minimum requirements to consistently induce CTLs and ADCC-mediating antibodies specific for the tumor form of MUC1 resulting in a therapeutic response in a mouse model of mammary cancer. The vaccine is composed of the immunoadjuvant Pam3CysSK4, a peptide Thelperepitope and an aberrantly glycosylated MUC1 peptide. Covalent linkage of the three components was essential for maximum efficacy. The vaccine produced CTLs, which recognized both glycosylated and nonglycosylated peptides, whereas a similar nonglycosylated vaccine gave CTLs which recognized only nonglycosylated peptide. Antibodies elicited by the glycosylated tripartite vaccine were significantly more lytic compared with the unglycosylated control. As a result, immunization with the glycosylated tripartite vaccine was superior in tumor prevention. Besides its own aptness as a clinical target, these studies of MUC1 are likely predictive of a covalent linking strategy applicable to many additional tumor-associated antigens.
Photo-ribonucleotide reductase β2 by selective cysteine labeling with a radical phototrigger
Authors: Pizano Arturo A. , Lutterman Daniel A. , Holder Patrick G. , Teets Thomas S. , Stubbe JoAnne , Nocera Daniel G.
Published: December 2011

Photochemical radical initiation is a powerful tool for studying radical initiation and transport in biology. Ribonucleotide reductases (RNRs), which catalyze the conversion of nucleotides to deoxynucleotides in all organisms, are an exemplar of radical mediated transformations in biology. Class Ia RNRs are composed of two subunits: α2 and β2. As a method to initiate radical formation photochemically within β2, a single surface-exposed cysteine of the β2 subunit of
Escherichia coli
Class Ia RNR has been labeled (98%) with a photooxidant ([Re ] = tricarbonyl(1,10-phenanthroline)(methylpyridyl)rhenium(I)). The labeling was achieved by incubation of S355C-β2 with the 4-(bromomethyl)pyridyl derivative of [Re] to yield the labeled species, [Re]-S355C-β2. Steady-state and time-resolved emission experiments reveal that the metal-to-ligand charge transfer (MLCT) excited-state
3
[Re ]
∗
is not significantly perturbed after bioconjugation and is available as a phototrigger of tyrosine radical at position 356 in the β2 subunit; transient absorption spectroscopy reveals that the radical lives for microseconds. The work described herein provides a platform for photochemical radical initiation and study of proton-coupled electron transfer (PCET) in the β2 subunit of RNR, from which radical initiation and transport for this enzyme originates.
Demography of Juvenile and Adult Brown Trout in Streams of Southeastern Minnesota
Authors: Dieterman Douglas J. , Hoxmeier R. John H.
Published: December 2011

We assessed recruitment, survival, emigration, and immigration of brown troutSalmo truttain six interconnected stream reaches to quantitatively estimate how much immigrants contributed to population size in reaches in southeastern Minnesota. We also examined the influence of reach and season on estimates of survival and emigration via mark and recapture of individual trout representing three groups (age‐0 juveniles, age‐1 and age‐2 adults, and age‐3+ large adults). Immigration was calculated as 1 minus emigration. Recruitment varied among the six reaches and 3 years of this study (range, 0–1,292 fish/km). Survival of the age‐0 group and that comprising ages 1 and 2 varied by season but not reach. Survival was highest in winter for both groups but lowest in spring for age‐0 trout and in fall for age‐1 and age ‐2 trout. Emigration varied by season for age‐0 trout but by reach for trout of ages 1 and 2. For age‐3+ trout, survival and emigration only varied by reach. Survival was highest and emigration was lowest in reaches with the most cover, including deep pools. From these demographic characteristics we estimated the proportions of the population that consisted of brown trout that had survived within a reach, recruited into it, or immigrated into it from some other reach. Immigration was predicted to contribute the most for the youngest age‐group (35% or more of the predicted abundance of age‐0 trout in most reaches) and is probably important for genetic purposes or to bolster population units in adjacent reaches. Our results for adult brown trout suggest that within‐reach recruitment and survival contribute a larger proportion of trout to population units in many reaches than do immigrants. This confirms the appropriateness of current management approaches and suggests that maintenance of the exceptional recreational brown trout fishery in southeastern Minnesota is at least solidly dependent on factors promoting recruitment and survival within most managed stream reaches.
Estimating Geographic Variation in Allometric Growth and Body Condition of Blue Suckers with Quantile Regression
Authors: Cade Brian S. , Terrell James W. , Neely Ben C.
Published: December 2011

Increasing our understanding of how environmental factors affect fish body condition and improving its utility as a metric of aquatic system health require reliable estimates of spatial variation in condition (weight at length). We used three statistical approaches that varied in how they accounted for heterogeneity in allometric growth to estimate differences in body condition of blue suckers Cycleptus elongatus across 19 large‐river locations in the central USA. Quantile regression of an expanded allometric growth model provided the most comprehensive estimates, including variation in exponents within and among locations (range = 2.88–4.24). Blue suckers from more‐southerly locations had the largest exponents. Mixed‐effects mean regression of a similar expanded allometric growth model allowed exponents to vary among locations (range = 3.03–3.60). Mean relative weights compared across selected intervals of total length (TL = 510–594 and 594–692 mm) in a multiplicative model involved the implicit assumption that allometric exponents within and among locations were similar to the exponent (3.46) for the standard weight equation. Proportionate differences in the quantiles of weight at length for adult blue suckers (TL = 510, 594, 644, and 692 mm) compared with their average across locations ranged from 1.08 to 1.30 for southern locations (Texas, Mississippi) and from 0.84 to 1.00 for northern locations (Montana, North Dakota); proportionate differences for mean weight ranged from 1.13 to 1.17 and from 0.87 to 0.95, respectively, and those for mean relative weight ranged from 1.10 to 1.18 and from 0.86 to 0.98, respectively. Weights for fish at longer lengths varied by 600–700 g within a location and by as much as 2,000 g among southern and northern locations. Estimates for the Wabash River, Indiana (0.96–1.07 times the average; greatest increases for lower weights at shorter TLs), and for the Missouri River from Blair, Nebraska, to Sioux City, Iowa (0.90–1.00 times the average; greatest decreases for lower weights at longer TLs), were examined in detail to explain the additional information provided by quantile estimates.
Modified Live Edwardsiella ictaluri Vaccine, AQUAVAC-ESC, Lacks Multidrug Resistance Plasmids
Authors: LaFrentz Benjamin R. , Welch Timothy J. , Shoemaker Craig A. , Drennan John D. , Klesius Phillip H.
Published: December 2011

Plasmid-mediated antibiotic resistance was first discovered in Edwardsiella ictaluri in the early 1990s, and in 2007 an E. ictaluri isolate harboring an IncA/C plasmid was recovered from a moribund channel catfish Ictalurus punctatus infected with the bacterium. Due to the identification of multidrug resistance plasmids in aquaculture and their potential clinical importance, we sought to determine whether the modified live E. ictaluri vaccine strain in AQUAVAC-ESC harbors such plasmids, so that the use of this vaccine will not directly contribute to the pool of bacteria carrying plasmid-borne resistance. Antimicrobial sensitivity testing of the E. ictaluri parent isolate and vaccine strain demonstrated that both were sensitive to 15 of the 16 antimicrobials tested. Total DNA from each isolate was analyzed by polymerase chain reaction (PCR) using a set of 13 primer pairs specific for conserved regions of the IncA/C plasmid backbone, and no specific products were obtained. PCR-based replicon typing of the parent isolate and vaccine strain demonstrated the absence of the 18 commonly occurring plasmid incompatibility groups. These results demonstrate that the vaccine strain does not carry resistance to commonly used antimicrobials and provide strong support for the absence of IncA/C and other commonly occurring plasmid incompatibility groups. Therefore, its use should not directly contribute to the pool of bacteria carrying plasmid-borne resistance. This work highlights the importance of thoroughly investigating potential vaccine strains for the presence of plasmids or other transmissible elements that may encode resistance to antibiotics.

Received May 6, 2011; accepted July 22, 2011
Use of Medicare Diagnosis and Procedure Codes to Improve Detection of Surgical Site Infections following Hip Arthroplasty, Knee Arthroplasty, and Vascular Surgery
Authors: Calderwood Michael S. , Ma Allen , Khan Yosef M. , Olsen Margaret A. , Bratzler Dale W. , Yokoe Deborah S. , Hooper David C. , Stevenson Kurt , Fraser Victoria J. , Platt Richard , Huang Susan S. ,   CDC Prevention Epicenters Program
Published: December 2011

Objective.

To evaluate the use of routinely collected electronic health data in Medicare claims to identify surgical site infections (SSIs) following hip arthroplasty, knee arthroplasty, and vascular surgery.

Design.

Retrospective cohort study.

Setting.

Four academic hospitals that perform prospective SSI surveillance.

Methods.

We developed lists of International Classification of Diseases, Ninth Revision, and Current Procedural Terminology diagnosis and procedure codes to identify potential SSIs. We then screened for these codes in Medicare claims submitted by each hospital on patients older than 65 years of age who had undergone 1 of the study procedures during 2007. Each site reviewed medical records of patients identified by either claims codes or traditional infection control surveillance to confirm SSI using Centers for Disease Control and Prevention/ National Healthcare Safety Network criteria. We assessed the performance of both methods against all chart-confirmed SSIs identified by either method.

Results.

Claims-based surveillance detected 1.8–4.7-fold more SSIs than traditional surveillance, including detection of all previously identified cases. For hip and vascular surgery, there was a 5-fold and 1.6-fold increase in detection of deep and organ/space infections, respectively, with no increased detection of deep and organ/space infections following knee surgery. Use of claims to trigger chart review led to confirmation of SSI in 1 out of 3 charts for hip arthroplasty, 1 out of 5 charts for knee arthroplasty, and 1 out of 2 charts for vascular surgery.

Conclusion.

Claims-based SSI surveillance markedly increased the number of SSIs detected following hip arthroplasty, knee arthroplasty, and vascular surgery. It deserves consideration as a more effective approach to target chart reviews for identifying SSIs.

Infect Control Hosp Epidemiol 2012;33(1):40-49
Frequent Hospital Readmissions for Clostridium difficile Infection and the Impact on Estimates of Hospital-Associated C. difficile Burden
Authors: Murphy Courtney R. , Avery Taliser R. , Dubberke Erik R. , Huang Susan S.
Published: December 2011

Objective.

Clostridium difficile infection (CDI) is associated with hospitalization and may cause readmission following admission for any reason. We aimed to measure the incidence of readmissions due to CDI.

Design.

Retrospective cohort study.

Patients.

Adult inpatients in Orange County, California, who presented with new-onset CDI within 12 weeks of discharge.

Methods.

We assessed mandatory 2000–2007 hospital discharge data for trends in hospital-associated CDI (HA-CDI) incidence, with and without inclusion of postdischarge CDI (PD-CDI) events resulting in rehospitalization within 12 weeks of discharge. We measured the effect of including PD-CDI events on hospital-specific CDI incidence, a mandatory reporting measure in California, and on relative hospital ranks by CDI incidence.

Results.

From 2000 to 2007, countywide hospital-onset CDI (HO-CDI) incidence increased from 15 per 10,000 to 22 per 10,000 admissions. When including PD-CDI events, HA-CDI incidence doubled (29 per 10,000 in 2000 and 52 per 10,000 in 2007). Overall, including PD-CDI events resulted in significantly higher hospital-specific CDI incidence, although hospitals had disproportionate amounts of HA-CDI occurring postdischarge. This resulted in substantial shifts in some hospitals' rankings by CDI incidence. In multivariate models, both HO and PD-CDI were associated with increasing age, higher length of stay, and select comorbidities. Race and Hispanic ethnicity were predictive of PD-CDI but not HO-CDI.

Conclusions.

PD-CDI events associated with rehospitalization are increasingly common. The majority of HA-CDI cases may be occurring postdischarge, raising important questions about both accurate reporting and effective prevention strategies. Some risk factors for PD-CDI may be different than those for HO-CDI, allowing additional identification of high-risk groups before discharge.

Infect Control Hosp Epidemiol 2012;33(1):20-28