bluuebunny/crossref_metadata_2025 huggingface dataset:
Early intrauterine transfusion in severe red blood cell alloimmunization
Authors: Yinon Y. , Visser J. , Kelly E. N. , Windrim R. , Amsalem H. , Seaward P. G. R. , Ryan G.
Published: May 2010

Objective

To determine perinatal outcome in pregnancies with early severe red blood cell (RBC) alloimmunization.

Methods

This was a retrospective analysis of 30 patients requiring their first intrauterine transfusion (IUT) at < 22 weeks of gestation. Timing of the first IUT was based on evaluation of either the middle cerebral artery peak systolic velocity (MCA‐PSV) or development of ascites.

Results

Thirty‐three per cent of the patients had experienced a previous intrauterine fetal death as a result of RBC alloimmunization. Of these alloimmunized pregnancies, 26 (87%) were associated with anti‐D, four (13%) with anti‐Kell and 12 had more than one antibody type involved. The antibody titers before the first IUT ranged from 1:128 to 1:8024. All fetuses were severely anemic before the first IUT with a median hemoglobin (Hb) level of 37 (range, 3–81) g/L. The nine hydropic fetuses had a lower Hb level compared with non‐hydropic fetuses (median 15 g/L vs. 42 g/L, P = 0.016). However, 15 (71%) non‐hydropic fetuses had an Hb level of < 50 g/L before the first IUT. The median gestational age at the first IUT was 20.4 (range, 16–22) weeks, and between one and nine transfusions were needed during pregnancy. Transfusion was via the intrahepatic vein (IHV) (n = 19), umbilical vein (n = 6) or umbilical artery (n = 2), or was intracardiac (n = 2) or intraperitoneal (n = 1). Overall perinatal survival rate was 80% and did not differ between hydropic and non‐hydropic fetuses. Median gestation at delivery, after exclusion of six intrauterine fetal deaths, was 36.7 (range, 27.8–38.4) weeks.

Conclusions

In early severe RBC alloimmunization, fetuses can be severely anemic without hydrops, and prognosis cannot be predicted by the presence or absence of hydrops. Early IUT followed by serial transfusions is associated with a perinatal survival rate of about 80%. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Linking climate change, environmental degradation, and migration: a methodological overview
Authors: Piguet Etienne
Published: May 2010

Empirical research focusing on the links between climate change, environmental degradation, and forced migration has risen significantly in recent years and uses an impressive variety of methods. The present article suggests a typology identifying six research method families: ecological inference based on area characteristics, individual sample surveys, time series, multilevel analysis, agent‐based modeling (ABM), and qualitative/ethnographic studies. The main technical features and empirical results of each family of methods are presented and critically discussed. We conclude by calling for a coordinated international effort to improve the quality and variety of data that could be used with existing research methods and significantly improve our understanding of the migration‐environment nexus. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Vulnerability and Adaptation to Climate Change > Learning from Cases and Analogies
SAUCeR,: a QoS‐aware slotted‐aloha based UWB MAC with cooperative retransmissions
Authors: Tan Hwee‐Xian , Chan Mun Choon , Kong Peng‐Yong , Tham Chen Khong
Published: May 2010

The inherent temporal connectivity and existence of impairments in wireless channels pose challenges to network performance. Cooperative communication has been proposed as an effective technique to mitigate the imperfections of the wireless medium by exploiting channel diversity and availability of neighboring nodes that can act as relays. Although numerous cooperative communication techniques have been proposed in the literature, most of them do not consider Quality of Service (QoS) issues in a wireless sensor network. In this work, we study how cooperative communication can be applied to achieve differentiated QoS in a sensor network that uses Ultra‐Wideband (UWB) as its underlying PHY layer technology. SAUCeR is a slotted‐aloha based ultra‐wideband medium access control protocol with cooperative retransmissions that provides differentiated QoS in networks with varying traffic classes. Despite the high transmission rates provided by UWB, its impulse‐based nature renders many conventional carrier sensing MAC protocols incompatible. Consequently, SAUCeR utilizes slotted‐aloha to reduce packet collisions without the need for carrier sensing. Differentiated QoS is provided by allocating different resources (time slots) to varying traffic classes to segregate the contention between them. A QoS‐aware cooperative retransmission technique and two distributed relay selection schemes are also introduced to improve overall traffic throughput and reduce end‐to‐end delay, while preventing the starvation of any traffic class. Copyright © 2010 John Wiley & Sons, Ltd.
An integrative cognitive neuroscience theory of social reasoning and moral judgment
Authors: Barbey Aron K. , Grafman Jordan
Published: May 2010

Cognitive neuroscience has made considerable progress in understanding the involvement of the prefrontal cortex (PFC) in social cognition and moral judgment. Accumulating evidence suggests that representations within the lateral PFC enable people to orchestrate their thoughts and actions in concert with their intentions to support goal‐directed social behavior. Despite the pivotal role of this region in guiding social interactions, remarkably little is known about the functional organization and forms of social knowledge mediated by the lateral PFC. Here, we review recent theoretical developments in evolutionary psychology and emerging evidence from the social and decision neuroscience literatures demonstrating the importance of the lateral PFC for orchestrating behavior on the basis of evolutionarily adaptive social norms for obligatory, prohibited, and permissible courses of action.WIREs Cogn Sci2011 2 55–67 DOI: 10.1002/wcs.84

This article is categorized under:

Psychology > Reasoning and Decision Making

Neuroscience > Behavior
Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm
Authors: Barthelmie R. J. , Jensen L. E.
Published: May 2010

Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under‐estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due to compensating edge effects. Copyright © 2010 John Wiley & Sons, Ltd.
GAS3, a developmentally regulated gene, encodes a highly mannosylated and inactive protein of the Gas family of Saccharomyces cerevisiae
Authors: Rolli Eleonora , Ragni Enrico , Rodriguez‐Peña José Manuel , Arroyo Javier , Popolo Laura
Published: May 2010

The multigene GAS family of Saccharomyces cerevisiae is constituted by five genes encoding GPI‐anchored proteins required for cell wall or spore wall assembly. GAS1 and GAS5 are expressed in vegetative growth and repressed during sporulation, whereas GAS2 and GAS4 exhibit the opposite expression pattern. This study focuses on GAS3, a still poorly characterized member of the family. To date, attempts to reveal the glucan elongase activity typical of Gas proteins have been unsuccessful, suggesting that Gas3p is the only inactive member of the family. Here, we compared the mRNA levels of GAS1, GAS3 and GAS5 and demonstrate that GAS3 is the weakest‐expressed paralogue in vegetative growth. Moreover, GAS3 mRNA increased during sporulation, showing a bimodal profile typical of the early–middle meiotic genes. GAS3 product was identified as a low‐abundance, polydisperse mannoprotein. Loss of Gas3p did not affect growth and sporulation. The overexpression of GAS3, driven by the GAS1 promoter, slightly reduced growth rate in a wild‐type strain and led to hyperaccumulation of Gas3p in the membranes and in the cell wall. To determine whether GAS3 could replace GAS1 function in vivo, GAS3 was also overexpressed in a gas1Δ mutant. Increased amounts of Gas3p were not only unable to complement the defects of the gas1Δ cells but exacerbated them. A mutated Gas3p–E283Q, where one of the catalytic glutamate residues essential for GH72 enzyme activity was replaced by glutamine, was also noxious to gas1Δ cells, indicating that the increased expression of Gas3p, rather than a potential activity, is deleterious for gas1Δ cells. Copyright © 2010 John Wiley & Sons, Ltd.
RE4[P1–x(C2)x]3 (RE = La–Nd): the Mixed Anionic Substructure Formed by Phosphorus and Carbon
Authors: Chizhov Pavel S. , Schnelle Walter , Burkhardt Ulrich , Schmidt Marcus , Prots Yurii , Antipov Evgeny V. , Grin Yuri
Published: May 2010

The rare‐earth phosphide carbides RE4[P1–x(C2)x]3 (RE = La, Ce, Pr, Nd) represent the first example of a mixed anionic substructure formed by phosphorus and carbon, being the first step toward the formation of the mixed inorganic P–C species. The peculiarities of the crystal structure, magnetic properties, XAS data, and quantum chemical calculation results confirm the ionic nature of the interaction between the rare‐earth cations RE and phosphorus anions, while complex interaction of π states of the C2 anions and d (and/or f) states of the RE components is indicated. Thus, despite the extensive chemical analogy between the phosphide carbides and phosphide silicides, the atomic interactions stabilizing the structural motif are slightly different.
The behavior of a zoo‐housed infant orangutan after the death of its mother
Authors: Whilde Jenny , Marples Nicola
Published: May 2010

The behavior of an infant female orangutan at Dublin Zoo before and after the death of her mother was recorded using scan sampling and compared. Social interactions and associations of the infant with the other individuals in the group were also compared before and after the death of her mother. Increases in climbing and object manipulation were observed, and a decrease in resting occurred. The infant orangutan significantly increased the amount of time she spent in close contact with another related adult female in the group after her mother's death. This case study describes an example of a zoo‐housed infant orangutan being successfully fostered by a related female without human intervention. It also provides a quantification of the behavior of an infant orangutan before and after being orphaned. Zoo Biol 30:205–211, 2011. © 2010 Wiley‐Liss, Inc.
Why are there so few aphid clones?
Authors: Loxdale H.D. , Massonnet B. , Weisser W.W.
Published: May 2010

In Europe, aphids contribute significantly to the so-called ‘aerial plankton’ during the spring to autumn months (growing season), although individual flight behaviour has been found, especially from molecular ecological studies, to be species-specific in terms of migratory range (ambit). Many of these species individuals may be assumed to be clonal in origin, that is, derived from a single asexual foundress. We are presently studying two specialist aphid species on Tansy,Tanacetum vulgareL. from samples collected in Jena, Germany –Macrosiphoniella tanacetaria(Kaltenbach) andMetopeurum fuscovirideStroyan, using microsatellite markers. On plotting the number of sets of different multilocus genotypes or MLGs (i.e. multiple clonal repeats: 1, 2, 3 copies, etc.), against the frequency of their occurrence, a negative exponential relationship was found, with populations of both species consisting mostly of single (i.e. unique) or low number repeats rather than larger multiple copy (clonal) MLG repeats. To test this further, microsatellite data collected from a previous study onM. tanacetariain Jena in the year 2000 and on samples of the Grain aphid,Sitobion avenae(F.), collected in the UK in 1997/8, the latter both in the field and from 12.2 m high suction traps, were examined in the same way. Again, similar relations were found, with most MLGs occurring as unique or low copy number repeats. The data are briefly discussed in the light of our evidence, as well as that of other similar studies on other aphid species, relating aphid molecular genetic data to aphid life cycle, behaviour and ecology.
Evidence for the continuous latent structure of mania in the Epidemiologic Catchment Area from multiple latent structure and construct validation methodologies
Authors: Prisciandaro J. J. , Roberts J. E.
Published: May 2010

Background

Although psychiatric diagnostic systems have conceptualized mania as a discrete phenomenon, appropriate latent structure investigations testing this conceptualization are lacking. In contrast to these diagnostic systems, several influential theories of mania have suggested a continuous conceptualization. The present study examined whether mania has a continuous or discrete latent structure using a comprehensive approach including taxometric, information-theoretic latent distribution modeling (ITLDM) and predictive validity methodologies in the Epidemiologic Catchment Area (ECA) study.

Method

Eight dichotomous manic symptom items were submitted to a variety of latent structural analyses, including factor analyses, taxometric procedures and ITLDM, in 10105 ECA community participants. In addition, a variety of continuous and discrete models of mania were compared in terms of their relative abilities to predict outcomes (i.e. health service utilization, internalizing and externalizing disorders, and suicidal behavior).

Results

Taxometric and ITLDM analyses consistently supported a continuous conceptualization of mania. In ITLDM analyses, a continuous model of mania demonstrated 6.52:1 odds over the best-fitting latent class model (LCM) of mania. Factor analyses suggested that the continuous structure of mania was best represented by a single latent factor. Predictive validity analyses demonstrated a consistent superior ability of continuous models of mania relative to discrete models.

Conclusions

The present study provided three independent lines of support for a continuous conceptualization of mania. The implications of a continuous model of mania are discussed.
At Home in the World? Mobilizing Inbetweenness in ‘Choreographing Identities’
Authors: WOLF SARA
Published: May 2010

Examining a programme of four solos by Los Angeles experimental dance artists Taisha Paggett, Rebecca Pappas, Christine Suarez and Hana van der Kolk, this short article argues how the choreographed subject-in-motion can be deployed as a political tactic to critique identity as a static category by capitalizing on the flux of moving bodies.
Indigenous Myth as Action and Activism: Jesusa Rodríguez and Liliana Felipe's El Maíz (Corn)
Authors: RODRÍGUEZ CHANTAL
Published: May 2010

The female body both as the locus for interrogating ideological, economical, political and social discourses, and for the transference of ideas, histories, myths, traditions and, ultimately, actions, is considered here in an analysis of Jesusa Rodríguez and Liliana Felipe's El Maíz.
Rewriting systems for the surface classification theorem
Authors: PULCINI GABRIELE
Published: May 2010

The work reported in this paper refers to Massey's proof of the surface classification theorem based on the standard word-rewriting treatment of surfaces. We arrange this approach into a formal rewriting systemand provide a new version of Massey's argument. Moreover, we study the computational properties of two subsystems of:orfor dealing with words denoting orientable surfaces andnorfor dealing with words denoting non-orientable surfaces. We show how such properties induce an alternative proof for the surface classification in which the basic homeomorphism between the connected sum of three projective planes and the connected sum of a torus with a projective plane is not required.
Laborwertveränderungen bei Anorexia nervosa
Authors: Baumann  , Heitmann  , Bubendorff  , Himmerich
Published: May 2010

Zur korrekten Diagnosestellung einer Anorexia nervosa ist die gezielte Anamnese gemäss den DSM-IV- oder -ICD-10-Kriterien in Verbindung mit einer körperlichen Untersuchung unerlässlich. Für den behandelnden Arzt ist es darüber hinaus aber sinnvoll, typische Laborwertveränderungen von Patienten mit Anorexia nervosa zu kennen, um hierdurch diagnostische Hinweise zu erhalten. Als typische Laborwertveränderungen, wenngleich diese nicht spezifisch für eine Anorexia nervosa sind, gelten Hyponatriämie, Hypokaliämie, Hypochlorämie, Leberenzymerhöhungen sowie niedrige Erythrozyten- und Leukozytenzahlen. Die Hormone Leptin, Neuropeptid Y (NPY), Trijodothyronin (T3), Follikel-stimulierendes Hormon (FSH), Luteinisierendes Hormon (LH) und Östrogen sind häufig erniedrigt, wohingegen Ghrelin, pankreatisches Polypeptid, Tumornekrosefaktor-α (TNF-α) und Kortisol typischerweise erhöht sein sollen.
Potential origins of 400–500 kyr periodicities in the ocean carbon cycle: A box model approach
Authors: Russon T. , Paillard D. , Elliot M.
Published: May 2010

Cenozoic proxy records of both the isotopic composition of dissolved inorganic carbon in the oceans (δ13CDIC) and deep ocean carbonate preservation show significant periodicities in the range 400–500 kyr. Sensitivity analysis of the ocean carbon cycle to potential variability on this timescale in patterns of global oceanic primary productivity and/or continental weathering fluxes is performed using a 7 box ocean‐atmosphere model. The data constraints imposed by Plio‐Pleistocene proxy records of δ13CDIC, carbonate preservation, and atmospheric pCO2 variability allow different scenarios to be evaluated. Forcing with the global oceanic primary production ratio of inorganic and organic carbon leads to the relative phases of response most consistent with the proxy data. However, only when changes also occur in total marine primary production can the observed relative amplitudes of δ13CDIC and pCO2 variability also be reproduced. This scenario is consistent with oscillations between a highly productive, coccolithophore‐rich global ocean and a less productive, diatom‐rich one. Such oscillations have been proposed to originate from the orbital eccentricity cycle leading to changes in seasonality and thus silica utilization in the Southern Ocean. However, the period of response in model δ13CDIC is always close to that of the forcing function used, and thus a significant discrepancy remains between the orbital eccentricity cycle period of 413 kyr and the observed ∼500 kyr δ13CDIC periodicity seen in the Pleistocene.
Numerical simulations of an ocean‐continent convergent system: Influence of subduction geometry and mantle wedge hydration on crustal recycling
Authors: Roda M. , Marotta A. M. , Spalla M. I.
Published: May 2010

The effects of the hydration mechanism on continental crust recycling are analyzed through a 2‐D finite element thermomechanical model. Oceanic slab dehydration and consequent mantle wedge hydration are implemented using a dynamic method. Hydration is accomplished by lawsonite and serpentine breakdown; topography is treated as a free surface. Subduction rates of 1, 3, 5, 7.5, and 10 cm/yr; slab angles of 30°, 45°, and 60°; and a mantle rheology represented by dry dunite and dry olivine flow laws have been taken into account during successive numerical experiments. Model predictions pointed out that a direct relationship exists between mantle rheology and the amount of recycled crustal material: the larger the viscosity contrast between hydrated and dry mantle, the larger the percentage of recycled material into the mantle wedge. Slab dip variation has a moderate impact on the recycling. Metamorphic evolution of recycled material is influenced by subduction style. TPmax, generally representative of eclogite facies conditions, is sensitive to changes in slab dip. A direct relationship between subduction rate and exhumation rate results for different slab dips; this relationship does not depend on the used mantle flow law. Thermal regimes predicted by different numerical models are compared to PT paths followed by continental crustal slices involved in ancient and recent subduction zones, making ablative subduction a suitable precollisional mechanism for burial and exhumation of continental crust.
Identification of prominence ejecta by the proton distribution function and magnetic fine structure in interplanetary coronal mass ejections in the inner heliosphere
Authors: Yao Shuo , Marsch Eckart , Tu Chuan‐Yi , Schwenn Rainer
Published: May 2010

This work presents in situ solar wind observations of three magnetic clouds (MCs) that contain cold high‐density material when Helios 2 was located at 0.3 AU on 9 May 1979, 0.5 AU on 30 March 1976, and 0.7 AU on 24 December 1978. In the cold high‐density regions embedded in the interplanetary coronal mass ejections we find (1) that the number density of protons is higher than in other regions inside the magnetic cloud, (2) the possible existence of He+, (3) that the thermal velocity distribution functions are more isotropic and appear to be colder than in the other regions of the MC, and the proton temperature is lower than that of the ambient plasma, and (4) that the associated magnetic field configuration can for all three MC events be identified as a flux rope. This cold high‐density region is located at the polarity inversion line in the center of the bipolar structure of the MC magnetic field (consistent with previous solar observation work that found that a prominence lies over the neutral line of the related bipolar solar magnetic field). Specifically, for the first magnetic cloud event on 8 May 1979, a coronal mass ejection (CME) was related to an eruptive prominence previously reported as a result of the observation of Solwind (P78‐1). Therefore, we identify the cold and dense region in the MC as the prominence material. It is the first time that prominence ejecta were identified by both the plasma and magnetic field features inside 1 AU, and it is also the first time that the thermal ion velocity distribution functions were used to investigate the microstate of the prominence material. Moreover, from our three cases, we also found that this material tended to fall behind the magnetic cloud and become smaller as it propagated farther away from the Sun, which confirms speculations in previous work. Overall, our in situ observations are consistent with three‐part CME models.
Dynamics of the ascent and eruption of water containing dissolved CO2 on Mars
Authors: Bargery Alistair Simon , Wilson Lionel
Published: May 2010

Volcanic activity on Mars can interact with the crust, providing CO2 to the hydrosphere and fracturing the cryosphere. We examine both heat transfer between magma and cryosphere ice and CO2 transfer between magma and aquifer water. Over the short time scales required to fracture the cryosphere, plausible amounts of CO2 transferred from magma are readily dissolved at the base of an aquifer under typical pressure and temperature conditions. We examine the physical mechanism by which, in some circumstances, subsurface water containing dissolved CO2 is released through fractures to the surface and emerges as a liquid fountain. All of the bulk densities of mixtures of water and released CO2, for the range of surface pressures found on Mars, are significantly greater than the atmosphere density. Using a series of models we find a relationship between the dissolved CO2 fraction in an aquifer and the height of a fountain that would form at the surface above a crustal fracture connecting the aquifer to the surface. Water eruption velocities range from ∼54 to ∼163 m s−1, leading to water fountain heights of at least a few hundred meters up to a few thousand meters with large CO2 content. Such fountains could be responsible for both the erosion observed at the source of Athabasca Vallis and the series of arcuate ridges surrounding the eastern end of the source graben of Mangala Vallis. Any mixtures of water and carbon dioxide that supplied the outflow channels in the Hesperian or Amazonian may have erupted as such fountains.
Public Opinion About Laws to Prohibit Weight Discrimination in the United States
Authors: Puhl Rebecca M. , Heuer Chelsea A.
Published: May 2010

Weight discrimination is pervasive in American society and impairs quality of life for obese persons. With approximately two‐thirds of Americans now overweight or obese, vast numbers of people are vulnerable to weight prejudice and its consequences. Currently, no laws exist to prohibit weight discrimination. This study conducted an online survey with a national sample of 1,001 adults (representing demographics of the United States) to examine public support for six potential legislative measures to prohibit weight discrimination in the United States. Results indicated substantial support (65% of men, 81% of women) for laws to prohibit weight discrimination in the workplace, especially for legal measures that would prohibit employers from refusing to hire, terminate, or deny promotion based on a person's body weight. Laws that proposed extending the same protections to obese persons as people with physical disabilities received the least support, suggesting that Americans may not be in favor of considering obesity as a disability. Findings also highlight specific predictors of support (related to sex, age, education, income, body weight, and political ideology). These findings can be used to inform policy makers in efforts to develop antidiscrimination laws. Such measures will rectify health disparities for overweight Americans and facilitate public health efforts to address obesity.
Sodium fluoride induces podosome formation in endothelial cells
Authors: Tatin Florence , Grise Florence , Reuzeau Edith , Genot Elisabeth , Moreau Violaine
Published: May 2010

Background information. Fluoride is a well‐known G‐protein activator. Exposure of cultured cells to its derivatives results in actin cytoskeleton remodelling. Podosomes are actin‐based structures endowed with adhesion and matrix‐degradation functions. This study investigates actin cytoskeleton reorganization induced by fluoride in endothelial cells.

Results. Treatment of cultured endothelial cells with sodium fluoride (NaF) results in a rapid and potent stimulation of podosome formation. Furthermore, we show that Cdc42 (cell‐division cycle 42), Rac1 and RhoA activities are stimulated in NaF‐treated cells. However, podosome assembly is dependent on Cdc42 and Rac1, but not RhoA. Although the sole activation of Cdc42 is sufficient to induce individual podosomes, a balance between RhoGTPase activities regulates podosome formation in response to NaF, which in this case are often found in groups or rosettes. As in other models, podosome formation in endothelial cells exposed to NaF also involves Src. Finally, we demonstrate that NaF‐induced podosomes are fully competent for matrix protein degradation.

Conclusions. Taken together, our findings establish NaF as a novel inducer of podosomes in endothelial cells in vitro.
ADAMs and protein disulfide isomerase: the key to regulated cell-surface protein ectodomain shedding?
Authors: Bass Rosemary , Edwards Dylan R.
Published: May 2010

The ADAM disintegrin metalloproteinases (where ADAM is ‘a disintegrin and metalloproteinase’) are a family of transmembrane cell-surface proteins with essential roles in adhesion and proteolytic processing in all animals. The archetypal family member is ADAM17 {also known as TACE [TNFα (tumour necrosis factor α)-converting enzyme]}, which is involved in processing pro-TNFα and in the activation of ligands for the EGFR [EGF (epidermal growth factor) receptor], as well as cleavage of diverse cell-surface receptors and adhesion molecules. ADAM-mediated shedding is itself influenced via cell signalling pathways. In this issue of the Biochemical Journal, Willems et al. make the observation that phorbol ester activates shedding by ADAM17 by affecting the activity of PDI (protein disulfide isomerase). They propose that PDI maintains ADAM17 in an inactive ‘closed’ state and PMA stimulation generates ROS (reactive oxygen species) and thus an altered redox environment, which in turn inactivates PDI and allows ADAM17 to adopt an ‘open’ active conformation. This activation is accompanied by changes in disulfide bonds in the ADAM17 ectodomain. This is a novel and exciting finding that could help to unlock the actions of ADAM sheddases, as well as a host of other mechanisms that rely upon rapid alterations in protein conformation on the cell surface.
New methods for capturing the mystery lipid, PtdIns5P
Authors: Backer Jonathan M.
Published: May 2010

The enormous versatility of phosphatidylinositol as a mediator of intracellular signalling is due to its variable phosphorylation on every combination of the 3′, 4′ and 5′ positions, as well as an even more complex range of phosphorylated products when inositol phosphate is released by phospholipase C activity. The phosphoinositides are produced by distinct enzymes in distinct intracellular membranes, and recruit and regulate downstream signalling proteins containing binding domains [PH (pleckstrin homology), PX (Phox homology), FYVE etc.] that are relatively specific for these lipids. Specific recruitment of downstream proteins presumably involves a coincidence detection mechanism, in which a combination of lipid–protein and protein–protein interactions define specificity. Of the seven intrucellular phosphoinositide, quantification of PtdIns5P levels in intact cells has remained difficult. In this issue of the Biochemical Journal, Sarkes and Rameh describe a novel HPLC-based approach which makes possible an analysis of the subcellular distribution of PtdIns5P and other phosphoinositides.
Cu adhesion on tantalum and ruthenium surface: Density functional theory study
Authors: Ding Shao-Feng , Deng Shao-Ren , Lu Hai-Sheng , Jiang Yu-Long , Ru Guo-Ping , Zhang David Wei , Qu Xin-Ping
Published: May 2010

This work reports a first-principles study of copper adhesion on Ta(110) and Ru(0001) surface with the density functional theory. Adsorption energy, electron density difference, and geometrical structures of Cu on pure, oxygen, and nitrogen doped Ta(110), Ru(0001) surfaces, and Ru doped Ta(110) surface were investigated. By analyzing the calculated results and the existing experimental results, it is found that although Ta has stronger chemical interaction with Cu, its larger lattice mismatch with Cu, and easy oxidation and nitridation make Ta a poorer Cu adhesion layer in comparison with Ru. The adhesion ability of Cu on Ta can be improved by doping Ru in Ta. The agglomeration of Cu on Ta or Ru is also studied. The calculation results show that Cu adsorbed on Ta(110) surface is more likely to be desorbed and agglomerated on the top of the second Cu atom layer. The substitutional oxygen OTa in Ta will stimulate the agglomeration of Cu on the Ta surface.
Interfacial structure and magnetic properties of Co2FeAl0.5Si0.5/MgO heterostructures
Authors: Hassan Sameh S. A. , Xu Yongbing , Hirohata Atsufumi , Sukegawa Hiroaki , Wang Wenhong , Inomata Koichiro , van der Laan Gerrit
Published: May 2010

The interfacial properties of the Co2FeAl0.5Si0.5/MgO based magnetic tunnel junction have been investigated using x ray absorption spectroscopy (XAS), angle resolved x ray photoelectron spectroscopy (ARXPS), x ray magnetic circular dichroism (XMCD), and element-specific hysteresis loops. The XAS demonstrates a multiplet structure at the Co L3 edge which could be attributed to the formation of CoO at the interface due to the high annealing temperature. The XMCD sum-rule analysis and the element-specific hysteresis loops show a higher magnetic moment, a change in the loop shape, and an increase in the Co coercive field when probing more close to the interface layer. The chemical and structural disorder at the interface has been further revealed by the ARXPS measurements.
Effect of high Xe-concentration in a plasma display panel with a SrCaO cold cathode
Authors: Uchida Giichiro , Uchida Satoshi , Akiyama Toshiyuki , Kajiyama Hiroshi , Shinoda Tsutae
Published: May 2010

We present here measurements of high Xe-contents plasma display panel (PDP) with SrCaO cold cathode. Luminous efficacy (η) shows a two-step increase with Xe-concentration in Ne/Xe gas mixture: η drastically increases up to Xe-concentration of 30% (Xe: 30%), and then attains 5 lm/W at the highest Xe-concentration of Xe: 100%. The high performance PDP with Xe: 100% can be operated at low applied voltage between 230 and 377 V due to the high secondary electron emission from the SrCaO cathode. Emission measurements clearly show the change in discharge characteristics at Xe: 30%, where the discharge changes from a Ne/Xe mixture discharge to an almost pure Xe discharge, and the vacuum ultraviolet (VUV) radiation from the combination of resonance and excimer radiations to only excimer radiation. Theoretical analysis solving Boltzmann equation for electron demonstrates that increasing Xe-concentration enhances the collision frequency for electron impact excitation directly from ground state to lower levels concerned with the VUV radiation, resulting in a drastic increase in luminous efficacy up to Xe: 30%. Also, one-dimensional fluid simulation of a Ne/Xe dielectric barrier discharge clearly shows that a combination of high secondary electron emission cathode and high Xe-concentration is quite effective for high VUV radiation efficiency because it induces a drastic increase in electron-heating efficiency.
Excitation induced tunable emission in biocompatible chitosan capped ZnS nanophosphors
Authors: Sharma Manoj , Singh Sukhvir , Pandey O. P.
Published: May 2010

Colloidal semiconductor nanomaterials exhibit color modulation which can be useful for various optoelectronic and biolabelling applications. Previous studies on CdSe and CdTe have shown tunable color modulation by varying the size of nanomaterials but toxicity of cadmium has created doubt for its end applications as biosensor. The recent work on ZnS:Mn2+ doped semiconductor has shown some viability for biolabelling but for tunable behavior particles of different doping concentration needs to be synthesized. In the present work all the above problems were considered and viable solution has been given to use ZnS:Mn2+ doped semiconductor using chitosan as capping agent. Here we report deliberate color modulation for chitosan capped ZnS:Mn2+ nanoparticles (NPs) synthesized in single step instead of many samples of different size. The tunable behavior is achieved by varying the excitation wavelength in same sample. Shifting of emission peak from dopant related emission at 590 nm (d states of Mn2+) to 481 nm defect related emission (Sulfur vacancy to Zn2+) and 421 nm (sulfur vacancy to valence band) has been observed. The work illustrates coupling between Frenkel exciton in organic polymers with Wannier exciton in inorganic semiconductors which has been observed for the present nanophosphors. Synthesized chitosan capped ZnS:Mn2+ NPs have been characterized by x-ray diffraction, high-resolution transmission electron microscopy, energy dispersive x-ray, and Fourier transform infrared for structural studies. UV visible absorption spectroscopy and Photoluminescence studies were done to observe optical behavior. Due to nontoxic nature of chitosan capped ZnS:Mn2+ with tunable color properties in single sample, these materials can be used as biolabels. Biocompatibility of chitosan functionalized ZnS:Mn quantum dots has been also verified with bacteria (staphylococcus aureus).
Polarization modification in InGaN/GaN multiple quantum wells by symmetrical thin low temperature-GaN layers
Authors: Tao Y. B. , Chen Z. Z. , Zhang F. F. , Jia C. Y. , Qi S. L. , Yu T. J. , Kang X. N. , Yang Z. J. , You L. P. , Yu D. P. , Zhang G. Y.
Published: May 2010

Light emitting diodes (LEDs) using InGaN/GaN quantum wells (QWs) with thin low temperature GaN (LT-GaN) layers bounding each InGaN layer are grown by metal-organic vapor phase epitaxy. The light output power of such LEDs increases by a factor of 2 at a drive current density of 35 A/cm2 compared to that from reference LEDs without the LT-GaN. The blueshift in the emission wavelength is 5.2 nm when the current density increases from 3 to 50 A/cm2, which is much smaller than the shift 8.1 nm from reference LEDs. Moreover, the efficiency droop at high current injection is also reduced by 28%, and current density at which peak efficiency is observed increases from 1 to 2 A/cm2. High resolution transmission electron microscopy of the QWs bounded with LT-GaN shows higher quality and less strain compared to the reference samples. The better performance of LEDs incorporating the LT-GaN layers is attributed to suppressed polarization from piezoelectric fields.
Evaluation of domain wall motion in bipolar fatigued lead-zirconate-titanate: A study on reversible and irreversible contributions
Authors: Glaum Julia , Granzow Torsten , Rödel Jürgen
Published: May 2010

Mobility of ferroelectric domain walls is a critical factor in the fatigue of piezoelectric ceramics. Here, reversible and irreversible domain wall motion is evaluated for lead-zirconate-titanate both before and after fatigue cycling. To this end, the small-signal permittivity at different levels of bias field is compared to the large-signal permittivity, i.e., the first derivative of the polarization hysteresis loop. While the small-signal permittivity is just determined by the reversible processes due to the small electric excitation field, the large-signal permittivity reflects both reversible and irreversible contributions. The ratio of large- and small-signal permittivity is suggested as measure for the reversible contribution to the overall polarization change. Fatigue leads to a decrease in the small-signal permittivity and hence a general suppression of the reversible processes. Furthermore it causes a shift in the irreversible contributions to higher electric fields and a retarded backswitching when the external electric field is reduced after the maximum field value was reached. This reinforces the notion of bipolar electric fatigue caused by pinned domain walls due to agglomeration of charged defects in the sample bulk.
Terahertz-wave radiation emitted by intrinsic Josephson junctions
Authors: Tachiki Takashi , Uchida Takashi
Published: May 2010

Radiation properties of terahertz (THz) electromagnetic waves emitted from stacks of 3 and 50 intrinsic Josephson junctions by flowing bias currents have been numerically investigated for high-frequency device applications. A novel multibranch structure in the resistive state was obtained for the current-voltage characteristics of the stacks. Each branch corresponded to an individual mode of a two-dimensional cavity resonance for Josephson plasma waves in the directions parallel and perpendicular to the c-axis of the stack. The electromagnetic field distribution in the stack exhibited standing-wave patterns not only for the in-phase mode between junctions but also for the other modes in different branches. Maximum radiation power was attained for the in-phase mode, and the corresponding bias point was measured for the 3- and 50-junction stacks. The peak power in the 50-junction stack was approximately 50 times larger than that in the 3-junction stack. The frequency spectra at maximum power exhibited a sharp main peak and a few harmonics. These properties are useful in designing a THz oscillator using intrinsic Josephson junctions.
On the pressure and temperature dependence of ordering temperature and magnetization of Y1−xThxCo4B compounds
Authors: Mayot H. , Isnard O. , Arnold Z. , Kamarad J.
Published: May 2010

We present here a detailed investigation of the pressure dependence of the structural and magnetic properties in a wide temperature range from 5 to 340 K for the Y1−xThxCo4B series. The unit cell lattice compressibility has been determined from powder neutron diffraction technique in the 0 to 0.5 GPa pressure range. Substitution of Th for Y is found to reduce significantly the compressibility. The Curie temperature decreases dramatically upon the Th for Y substitution. Studies were performed on polycrystalline samples under hydrostatic pressure up to 1.1 GPa and in magnetic field up to 5 T. The evolution of the saturation magnetization under pressure is presented as well as the pressure dependence of the Curie temperature. Remarkable pressure effects on the Curie temperature and on the critical field at which the first order magnetization process occurs for Y0.8Th0.2Co4B are analyzed and discussed. The pressure derivatives values of both the Curie temperature and the magnetization are negative for all the studied compounds. This is an opposite tendency than that expected from chemical pressure effects. This supports the dominant role of valence electrons in the magnetic properties of the substituted Y1−xThxCo4B compound in the case of the chemical pressure effect. The magnetization and the Curie temperature exhibit different pressure dependence along the Y1−xThxCo4B series of compounds.
An alternate approach to study electrostatic solitary waves in homogeneous and inhomogeneous quantum magnetoplasmas
Authors: Masood W.
Published: May 2010

Ion acoustic drift solitary wave is studied in both linear and nonlinear regimes in an electron-ion quantum magnetoplasma. It is shown that using the linear dispersion relation, nonlinear Zakharov–Kuznetsov (ZK) equation can be derived in an inhomogeneous quantum magnetoplasma for ion acoustic drift solitary wave in a certain parametric range. The solution of the ZK equation is also presented using the tangent hyperbolic method. It is found that the quantum Bohm potential (via increasing number density), angle of propagation, and the magnetic field affect the propagation characteristics of the nonlinear quantum ion acoustic drift wave. The results presented in this paper may be beneficial to understand the formation of electrostatic drift solitary waves in dense magnetized plasmas.
Instabilities in the spin-up of a rotating, stratified fluid
Authors: Munro R. J. , Foster M. R. , Davies P. A.
Published: May 2010

Theoretical analyses and laboratory experiments have been performed on the stability of a flow generated by the differential cyclonic corotation of a flat, rigid disk in a uniformly rotating, linearly stratified fluid contained within a cylindrical tank. The undisturbed fluid is stably stratified with salt (Schmidt number σ≈670) and the (vertical) axes of rotation of the disk and the fluid container are coincident. The theoretical analysis shows that when the interior flow satisfies gradient wind balance (or, alternatively, thermal wind balance), it is destabilized by the action of viscosity. In the experiments, the manifestation of the viscous overturning instability is seen to be the formation of steplike internal microstructures in the density field, observed as regularly spaced, curved ring-shaped sheets with associated localized sharp, vertical density gradients. A stability analysis of the flow shows that the instability criterion is dependent on local values of the vertical and radial gradients of zonal velocity and the background density field. These quantities are measured in the experiments using a combination of horizontal-plane particle image velocimetry and an array of traversing microconductivity probes. The stability criterion based on this linear analysis predicts that the interior of the fluid is unstable. Using the σ⪢1 condition, simple asymptotic expressions for the maximum growth rate and associated wave number have been derived from the cubic dispersion relation. The theoretically predicted length scales and e-folding times associated with the fastest growing modes are found to give excellent agreement with the corresponding values obtained from the laboratory experimental data.
Force generated by a swelling elastomer subject to constraint
Authors: Cai Shengqiang , Lou Yucun , Ganguly Partha , Robisson Agathe , Suo Zhigang
Published: May 2010

When an elastomer imbibes a solvent and swells, a force is generated if the elastomer is constrained by a hard material. The magnitude of the force depends on the geometry of the constraint, as well as on the chemistry of the elastomer and solvent. This paper models an elastomer crosslinked on the exterior surface of a metallic tubing. The elastomer then imbibes a solvent and swells. After the swollen elastomer touches the wall of the borehole, a significant amount of time is needed for the solvent in the elastomer to redistribute, building up the sealing pressure to the state of equilibrium. The sealing pressure and the sealing time are calculated in terms of the geometric parameters (i.e., the thickness of the elastomer and the radii of the tubing and borehole), the number of monomers along each polymer chain of the elastomer, and the affinity between the elastomer and the solvent.
Note: X-ray streak camera sweep speed calibration
Authors: Zhu Tuo , Yang Jia-Min , Deng Bo , Yang Dong , He Xiao-an , Wang Zhe-bin
Published: May 2010

X-ray streak cameras are extensively used to study transient x-ray processes in experiments carried out on various laser facilities at the Research Center of Laser Fusion. Precise calibration and clear description of the sweep speed of the x-ray streak camera are vital for obtaining precise temporal information to understand the fast physics phenomena. An x-ray streak camera named wide-slit x-ray streak camera has been calibrated using a small-scale laser facility with pulse duration of 8 ps. Sweep speeds on most part of the output screen (charge coupled device) are obtained. These calibration results can be used to correct the nonlinearity of sweep speed in measurement of temporal processes.
Liquid crystalline phase in ethanol suspension of anisometric 4-cyano-4-n-hexylbiphenyl microcrystals: Witnessed by dielectric spectroscopy
Authors: Chen Zhen , Nozaki Ryusuke
Published: May 2010

The suspensions of 4-cyano-4-n-hexylbiphenyl (6CB) anisometric microcrystal were obtained by quenching homogeneous 6CB/ethanol mixtures with different 6CB concentrations. Such suspensions were strongly suggested from the differential scanning calorimetry examinations and the image observations of the samples during the quench and heating processes. The crystallization process for the mixtures with higher 6CB concentration looked like the isotropic-nematic phase transition of bulk liquid crystal. Dielectric measurement was carried out on the mixtures during the heating process after quench. Distinct dielectric relaxation was observed in the frequency range between kHz and 100 kHz, which exhibited obvious dependence on temperature and 6CB concentration. Curve fitting on the complex conductivity spectra indicates that three Debye type relaxations exist in this narrow frequency range. Based on the dependences of relaxation parameters on temperature and 6CB concentration, the possible relaxation mechanisms and the phase conformation of the mixtures were discussed. It was concluded that the relaxations, from high to low relaxation frequency, originate from the Maxwell–Wagner polarization, the rotation of 6CB microcrystal around its long axis, and the reorientation of 6CB microcrystal around its short axis, respectively. It was also confirmed that the quenched 6CB/ethanol mixtures show isotropic-nematic phase transition with the increase of 6CB concentration.