bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects and Costs of a Multifactorial and Interdisciplinary Team Approach to Falls Prevention for Older Home Care Clients ‘At Risk’ for Falling: A Randomized Controlled Trial
Authors: Markle-Reid Maureen , Browne Gina , Gafni Amiram , Roberts Jacqueline , Weir Robin , Thabane Lehana , Miles Melody , Vaitonis Vida , Hecimovich Catherine , Baxter Pamela , Henderson Sandra
Published: March 2010

Cette étude a déterminé les effets et les coûts d’une approche d’équipe multifactoriel et interdisciplinaire à la prévention des chutes. Essai contrôlé aléatoire de 109 adultes plus âgés qui sont à risque de chutes. Ce fut une stratégie de prévention multifactoriel fondée sur des données probantes de 6 mois, impliquant une équipe interdisciplinaire. Le résultat principal a été le nombre des chutes suivi pendant 6 mois. À 6 mois, il n’y a aucune différence dans le nombre moyen de chutes entre groupes. Des analyses des sous-groupes ont montrés que l’intervention réduit efficacement les chutes chez les hommes (75–84 ans) qui ont peur de tomber ou une histoire négative de chutes. Le nombre de glissades et de trébuchés a été considérablement réduit, et la santé émotionnelle a montré une amélioration plus importante dans le fonctionnement lié à la santé émotionnelle dans le groupe d’intervention. La qualité de vie a été améliorée, glissades et trébuchés ont été réduits, comme l’étaient les chutes chez les hommes qui avaient peur de tomber ou une histoire de chutes négative.
What Will the Family Composition of Older Persons Be Like Tomorrow? A Comparison of Canada and France
Authors: Gaymu Joëlle , Busque Marc-Antoine , Légaré Jacques , Décarie Yann , Vézina Samuel , Keefe Janice
Published: March 2010

L’ensemble des sociétés occidentales connaissent actuellement une croissance considérable des personnes âgées de 75 ans et plus. De nombreux changements familiaux affectant ces sociétés, il est pertinent de se demander qui prendra en charge les aînés de demain en cas de besoin d’assistance. Cet article compare les projections démographiques du réseau familial des personnes âgées de 75 ans et plus jusqu’en 2030 au Canada et en France. Au cours des 25 années prochaines, le vivier des aidants familiaux potentiels, constitué des conjoint(e)s et des enfants, s’élargira en raison des effets du Baby Boom (dont l’ampleur a été particulièrement forte au Canada) et de la proportion croissante de femmes qui ont un conjoint. Les populations les plus tributaires de l’aide formelle – sans soutien potentiel provenant d’un enfant ou d’un conjoint – augmenteront à un rythme beaucoup plus soutenu au Canada (123 pour cent) qu’en France (34 pour cent), mais moins rapidement toutefois que l’ensemble des personnes âgées. Les politiques publiques de ces deux pays devront être adaptées afin de soutenir adéquatement des effectifs croissants de personnes âgées confrontés à la dépendance de leurs conjoints. Au Canada, ces politiques devront, de plus, faire face à une hausse, plus forte qu’en France, du nombre d’aînés qui dépendront des services d’aide formelles.
Oceanographic observations of eddies impacting the Prince Edward Islands, South Africa
Authors: Durgadoo Jonathan V. , Ansorge Isabelle J. , Lutjeharms Johann R.E.
Published: March 2010

The ecosystem of the isolated Prince Edward Islands, south of the African continent, is strongly impacted by ocean eddies that are associated with the eastward flowing Antarctic Circumpolar Current. Satellite altimetry has revealed that the archipelago lies in a region of enhanced eddy kinetic energy. In the late 1990s it became apparent that in order to understand the influence of these eddies on the islands’ ecosystem, the source, trajectory and nature of these eddies needed to be studied and understood. To this end a special research project with a strong ocean-going component was designed, the DEIMEC (Dynamics of Eddy Impact on Marion’s ECosystem) programme. In this review we focus on the physical oceanography and summarize the aims, the results and the successes of this South African research initiative. In the vicinity of the Prince Edward Islands, an average of three intense well-defined eddies is observed per year. Their advection speeds are of the order of a few kilometres per day and longevities of 7–11 months. These features, ofc.100 km in diameter and reaching depths of at least 1000 m, transport anomalous water masses across the Polar Frontal Zone.
Experience from a single centre concerning the surgical spectrum and outcome of adolescents and adults with congenitally malformed hearts in West Africa
Authors: Edwin Frank , Sereboe Lawrence A. , Tettey Mark M. , Aniteye Ernest A. , Kotei David A. , Tamatey Martin M. , Entsua-Mensah Kow , Frimpong-Boateng Kwabena
Published: March 2010

Background

This study was undertaken to review the spectrum and surgical outcome of adolescents and adults with congenitally malformed hearts from January, 1993 to December, 2008. The lack of data on this emerging problem from the West African sub-region prompted this report.

Patients and Method

This retrospective study is based on 135 adolescents and adults with congenitally malformed hearts. A review of their case notes and operative records was carried out and results analysed.

Results

Selected patients made up 23% of all congenital cardiac surgeries performed at our institution in the same period. A total of 23 patients (17%) were non-Ghanaian West Africans. There was a female preponderance of 53.3%. The ages ranged from 16 to 70 years (mean 28.6 plus or minus 10.3 years). The mean follow-up was 7.5 plus or minus 4.4 years. Patients were functionally classified (New York Heart Association) as class I (23%), II (58%), and III (19%). In 14 (10.4%) patients, the defects were discovered incidentally. Ventricular septal defects, oval fossa type atrial septal defects, Fallot’s tetralogy, and patent arterial duct together accounted for 77.8% of the cases. Surgical correction was undertaken in 117 (86.7%) patients; the remainder had palliative procedures. There were six (4.3%) reoperations. The functional class improved to class I or II in 95% of patients within the first postoperative year. The overall hospital mortality was 3% with two late deaths (1.5%).

Conclusion

The study demonstrates the feasibility of surgery for adolescents and adults with congenitally malformed hearts in the sub-region with a good outcome. Majority (77.8%) of patients present with less complex lesions.
Improving results of atrioventricular valve repair in challenging patients with heterotaxy syndrome
Authors: Ota Noritaka , Fujimoto Yoshifumi , Hirose Keiichi , Tosaka Yuko , Nakata Tomohiro , Ide Yujiro , Sakamoto Kisaburo
Published: March 2010

Objectives

Heterotaxy syndrome, which is often associated with atrioventricular valvar regurgitation, has been considered a risk factor for the surgical repair for Fontan candidates. The results of atrioventricular valve repair in this challenging patient population remain largely unknown.

Methods

From July, 1994 to January, 2007, 25 patients with the heterotaxy syndrome consisting of 22 right isomerism and three left isomerism presented to the Shizuoka Children’s Hospital Japan with significant (3–4+) atrioventricular valvar regurgitation necessitating atrioventricular valve repair. The clinical and Doppler/echocardiographic data were retrospectively reviewed to determine the efficacy of the repair and patient outcome.

Results

Patients were divided into two groups on the basis of atrioventricular valvar regurgitation at the most recent follow-up: those with a successful late outcome, (0–2) and those with a poor outcome (3–4). There were 17 (67%) patients with a successful outcome and 8 (33%) with a poor outcome. The repair technique including leaflet apposition was predictive of a successful outcome (p = 0.003). Overall survival was 64% (16/25). Survival was 88.2% (15/17) for patients with a successful result versus 12.5% (1/8) for those with a poor outcome (p = 0.0007). Of the 15 survivors, 13 have reached final completion of the Fontan circulation, and two currently remain at the bi-directional Glenn shunt stage.

Conclusion

Atrioventricular valve repair can be accomplished in this challenging patient population with excellent results. The combination of the leaflet apposition technique and the Kay suture can be performed with an excellent outcome in the majority of patients with heterotaxy syndrome, even with significant atrioventricular valvar regurgitation.
Magnetic resonance imaging findings in Loeys–Dietz syndrome
Authors: Valverde Israel , Simpson John , Beerbaum Philipp
Published: March 2010

Loeys–Dietz syndrome is a newly described entity characterised by a constellation of arterial tortuosity, cranial malformations, and hypertelorism. We report a case of a 7-year old boy with confirmed Loeys–Dietz syndrome and discuss magnetic resonance imaging as a complete technique for assessment and follow-up of aggressive vascular pathology in the brain, thorax, and abdomen, which may dictate early surgical intervention.
A NOTE ON ENTREPRENEURIAL RISK, CAPITAL MARKET IMPERFECTIONS, AND HETEROGENEITY
Authors: Luo Yulei , Gong Liutang , Zou Heng-fu
Published: March 2010

Empirical evidence shows that entrepreneurs hold a large fraction of wealth, have higher saving rates than workers, and face substantial uninsurable entrepreneurial and investment risks. This paper constructs a heterogeneous-agent general equilibrium model with uninsurable entrepreneurial risk and capital-market imperfections to explore the implications of uninsurable entrepreneurial risk for wealth distribution and aggregate activity in an incomplete market economy. It is shown that entrepreneurial risk can substantially affect both the wealth distribution and the macroeconomy.
LIFE CYCLE OF PRODUCTS AND CYCLES
Authors: De Beir Jean , Fodha Mouez , Magris Francesco
Published: March 2010

The aim of this paper is to examine whether the development of waste recycling activities can be a source of economic fluctuations. We assume that the recycling sector has four fundamental characteristics. (i) The production factors are restricted by the production of the last period. (ii) These production factors are waste for which the price determination is noncompetitive. (iii) The sector produces a recycled good, which is a perfect substitute for the primary good. (iv) It reduces the waste stream. We consider the simplest economy, with an infinitely lived agent and a life-cycle hypothesis for the goods. We show that the equilibrium is unique and is always determinate. In spite of the lack of indeterminacy, however, our economy can display cyclical behavior, depending on some usual conditions on parameters. Namely, the steady state may undergo a flip bifurcation or a Hopf bifurcation.
A Transmission Electron Microscopy Study of CoFe2O4 Ferrite Nanoparticles in Silica Aerogel Matrix Using HREM and STEM Imaging and EDX Spectroscopy and EELS
Authors: Falqui Andrea , Corrias Anna , Wang Peng , Snoeck Etienne , Mountjoy Gavin
Published: March 2010

Magnetic nanocomposite materials consisting of 5 and 10 wt% CoFe2O4 nanoparticles in a silica aerogel matrix have been synthesized by the sol-gel method. For the CoFe2O4-10wt% sample, bright-field scanning transmission electron microscopy (BF STEM) and high-resolution transmission electron microscopy (HREM) images showed distinct, rounded CoFe2O4 nanoparticles, with typical diameters of roughly 8 nm. For the CoFe2O4-5wt% sample, BF STEM images and energy dispersive X-ray (EDX) measurements showed CoFe2O4 nanoparticles with diameters of roughly 3 ± 1 nm. EDX measurements indicate that all nanoparticles consist of stoichiometric CoFe2O4, and electron energy-loss spectroscopy measurements from lines crossing nanoparticles in the CoFe2O4-10wt% sample show a uniform composition within nanoparticles, with a precision of at best than ±0.5 nm in analysis position. BF STEM images obtained for the CoFe2O4-10wt% sample showed many “needle-like” nanostructures that typically have a length of ∼10 nm and a width of ∼1 nm, and frequently appear to be attached to nanoparticles. These needle-like nanostructures are observed to contain layers with interlayer spacing 0.33 ± 0.1 nm, which could be consistent with Co silicate hydroxide, a known precursor phase in these nanocomposite materials.
European policymaking on the tobacco advertising ban: the importance of escape routes
Authors: Adamini Sandra , Versluis Esther , Maarse Hans
Published: March 2010

This article analyses the European Union policymaking process regarding tobacco advertising. While others already highlighted the importance of intergovernmental bargaining between member states to explain the outcome of the tobacco advertising case, the main aim of this article is to identify the use of escape routes by the Commission, the European Parliament, the Council and interest groups that played an important role in overcoming the deadlock. When looking at the different institutions that structure policymaking, we argue that indeed focusing on escape routes provides a clear insight in the process and in what strategies were necessary to ‘make Europe work’. In the end, it appears to be a combination of escape routes that resulted in the final decision.
Satellite retrievals of (quasi‐)spherical particles at cold temperatures
Authors: Choi Yong‐Sang , Ho Chang‐Hoi , Kim Jinwon , Lindzen Richard S.
Published: March 2010

Measurements from NASA's A‐train satellites indicate that spherical or quasi‐spherical particles may constitute up to 30% of the total cloud particles at temperatures below −30°C, and up to 10% even for temperatures below −40°C, the temperature range typically found in the upper troposphere and the lower stratosphere. Current climate models calculate cloud radiative forcing on the basis on an assumption that essentially no spherical or quasi‐spherical particles exist below −40°C (even below −15°C). The findings in this study show that this widely used assumption in climate models may need re‐examination. Further research is also needed to confirm and quantify these findings, especially improvements in the satellite retrievals of cloud particle shapes that, in the mean, currently contain about 10% uncertainties.
Amazon forests did not green‐up during the 2005 drought
Authors: Samanta Arindam , Ganguly Sangram , Hashimoto Hirofumi , Devadiga Sadashiva , Vermote Eric , Knyazikhin Yuri , Nemani Ramakrishna R. , Myneni Ranga B.
Published: March 2010

The sensitivity of Amazon rainforests to dry‐season droughts is still poorly understood, with reports of enhanced tree mortality and forest fires on one hand, and excessive forest greening on the other. Here, we report that the previous results of large‐scale greening of the Amazon, obtained from an earlier version of satellite‐derived vegetation greenness data ‐ Collection 4 (C4) Enhanced Vegetation Index (EVI), are irreproducible, with both this earlier version as well as the improved, current version (C5), owing to inclusion of atmosphere‐corrupted data in those results. We find no evidence of large‐scale greening of intact Amazon forests during the 2005 drought ‐ approximately 11%–12% of these drought‐stricken forests display greening, while, 28%–29% show browning or no‐change, and for the rest, the data are not of sufficient quality to characterize any changes. These changes are also not unique ‐ approximately similar changes are observed in non‐drought years as well. Changes in surface solar irradiance are contrary to the speculation in the previously published report of enhanced sunlight availability during the 2005 drought. There was no co‐relation between drought severity and greenness changes, which is contrary to the idea of drought‐induced greening. Thus, we conclude that Amazon forests did not green‐up during the 2005 drought.
Numerical determination of the efficiency of entrainment in volcanic eruption columns
Authors: Suzuki Y. J. , Koyaguchi T.
Published: March 2010

Entrainment of air by turbulent mixing plays a central role in the dynamics of eruption clouds; the amount of entrained air controls eruption styles and heights of eruption columns. The efficiency of entrainment is quantified by the entrainment coefficient: the ratio between mean inward radial velocity at the edge and the mean vertical velocity. We directly determined the entrainment coefficient of eruption columns as a function of height on the basis of three‐dimensional numerical simulations. The value of entrainment coefficient is similar to that for pure jets (∼0.07) just above the vent, and approaches that for pure plumes (0.10–0.15) far from the vent. Between these two regions, we identify a new transitional zone with a significantly small entrainment coefficient (∼0.05). This spatial variation in the entrainment coefficient is correlated with the change in vortical structure accompanying the addition of off‐source buoyancy in the transitional zone.
Three‐dimensional hybrid simulation of magnetosheath reconnection under northward and southward interplanetary magnetic field
Authors: Pang Y. , Lin Y. , Deng X. H. , Wang X. Y. , Tan B.
Published: March 2010

A three‐dimensional (3‐D) global hybrid simulation is carried out for the generation and structure of magnetic reconnection in the magnetosheath because of the interaction of an interplanetary tangential discontinuity (TD) with the bow shock and magnetosphere. Runs are performed for solar wind TDs possessing different polarization senses of magnetic field (north‐to‐south or south‐to‐north from the leading to trailing side of the incident TD) and initial half‐widths. Two‐step compression processes are shown in the transmitted TD, including a “shock compression,” as the TD passes through the shock followed by a subsequent “convective compression” while the TD is moving in the magnetosheath toward the magnetopause. In cases with a relatively thin solar wind TD, 3‐D patchy reconnection is initiated in the transmitted TD, forming magnetosheath flux ropes. Differences between these flux ropes and those due to magnetopause reconnection are discussed. Multiple components of ion particles are present in the velocity distribution in the magnetosheath merging, accompanied by ion heating. For cases with a relatively wide initial TD, a dominant single X line appears in the subsolar magnetosheath after the transmitted TD is narrowed through the two‐step compression process. Specifically, in the cases with a south‐to‐north field rotation across an incident thin TD, the magnetosheath flux ropes could re‐reconnect with the closed geomagnetic field lines to generate a closed field line region with mixed magnetosheath and magnetospheric plasmas, which may contribute to the transport of solar wind plasma into the magnetospheric boundary layer.
Energetic electron microsignatures as tracers of radial flows and dynamics in Saturn's innermost magnetosphere
Authors: Roussos E. , Krupp N. , Paranicas C. P. , Mitchell D. G. , Müller A. L. , Kollmann P. , Bebesi Z. , Krimigis S. M. , Coates A. J.
Published: March 2010

Signatures of energetic electron depletions from Saturn's inner moons (microsignatures) have been mainly utilized to infer properties of magnetospheric diffusion. The same data, however, indicate that microsignatures can be a much more powerful tool for magnetospheric studies. Here we introduce a new method where the energy structure of a microsignature can be used to trace the location, the formation date, the evolution, and the physical properties of dynamic events in the inner Saturnian magnetosphere. Application to a complex electron microsignature of Tethys, seen by Cassini's MIMI/LEMMS and CAPS/ELS detectors, reveals the location and the age of such an event. The development stages of this event, that can also be distinguished, indicate the presence of local, pulse‐like azimuthal electric field variations that can locally enhance radial transport by a factor of 1000–3000 with respect to radial diffusion. We also extract several physical properties of this dynamical region and speculate about its possible nature.
Radiation of plasma waves by a conducting body moving through a magnetized plasma
Authors: Biancalani A. , Pegoraro F.
Published: March 2010

The emission of plasma waves by a conducting body orbiting the ionosphere is considered. The case of an infinitely long and infinitely thin tether is discussed and the use of the appropriate form of the wave dispersion relation in the frequency regime of interest is shown to reconcile existing results in the literature. A compact formula for the radiation resistance of the tether is provided.
Temporal changes of subsurface velocities during strong shaking as seen from seismic interferometry
Authors: Yamada Masumi , Mori Jim , Ohmi Shiro
Published: March 2010

We apply a deconvolution method to a strong motion data set recorded at the surface and in boreholes in northeast Honshu, Japan. We try to characterize the nonlinear effects of the subsurface soil during strong shaking and show the change of the subsurface velocity structure during the shaking. The deconvolved waveforms reflect the subsurface velocity structure, and their horizontal and vertical components correspond to S and P wave, respectively, traveling from the borehole to the ground surface. The strong motion records with smaller values of peak acceleration do not include significant nonlinear effects, so the deconvolved waveforms of the observed accelerations can be well simulated by the program SHAKE91. For high acceleration motions during the shaking of two separate earthquakes, large reductions of near‐surface velocities are seen. In results for the 2008 Iwate‐Miyagi Nairiku earthquake, the large high‐frequency ground motions over 4g at one near‐source station caused a nonlinear response of the soil, and the reduction of the average shear wave velocity reached 24%. This corresponds to a stiffness change of over 75%. The soil properties and the stiffness coefficient which changed during the shaking did not fully recover after the shaking, leaving a static change.
Improving the altimetric rain record from Jason‐1 and Jason‐2
Authors: Quartly G. D.
Published: March 2010

Dual‐frequency rain flagging has long been a standard part of altimetric data analysis, both for quality control of the data and for the study of rain itself, because altimeters can provide a finer spatial sampling of rain than passive microwave instruments can. However, there have been many varied implementations, using different records of the surface backscatter and different thresholds. This paper compares four different measures available for the recently launched Jason‐2. The evaluation compares these measures against clearly desired properties, finding that in most cases the adjusted backscatter and that from the ice retracker perform much better than the one recommended in the users' handbook. The adjusted backscatter measure also provides a much better link to observations from Jason‐1, opening up a much longer period for consistent rain investigations and enabling greatly improved analysis of the short‐scale variability of precipitation. Initial analysis shows that although the spatial and temporal gradients of backscatter increase at very low winds, the spatial gradients in rain attenuation are concentrated where rainfall is greatest, while the temporal changes have a simple broad latitudinal pattern.
Meteorological atmospheric boundary layer measurements and ECMWF analyses during summer at Dome C, Antarctica
Authors: Genthon Christophe , Town Michael S. , Six Delphine , Favier Vincent , Argentini Stefania , Pellegrini Andrea
Published: March 2010

Six levels of meteorological sensors have been deployed along a 45 m tower at the French‐Italian Concordia station, Dome C, Antarctic. We present measurements of vertical profiles, the diurnal cycle, and interdiurnal variability of temperature, humidity, and wind speed and direction for 3 weeks during the southern summer of 2008. These measurements are compared to 6‐hourly European Center for Medium‐Range Forecasts (ECMWF) analyses and daily radiosoundings. The ECMWF analyses show a 3–4°C warm bias relative to the tower observations. They reproduce the diurnal cycle of temperature with slightly weaker amplitude and weaker vertical gradients. The amplitude of the diurnal cycle of relative humidity is overestimated by ECMWF because the amplitude of the absolute humidity diurnal cycle is too small. The nighttime surface‐based wind shear and Ekman spiral is also not reproduced in the ECMWF analyses. Radiosonde temperatures are biased low relative to the tower observations in the lowest 30 m but approach agreement at the top of the tower. Prior to bias correction for age‐related contamination, radiosonde relative humidities are biased low relative to the tower observations in the lowest 10 m but agree with tower observations above this height. After correction for the age‐related bias, the radiosonde relative humidity agrees with tower observations below 10 m but is biased high above this height. Tower temperature observations may also be biased by solar heating, despite radiation shielding and natural ventilation.
Whisker's Directional Selectivity: Orientation Columns in the Barrel Field?
Authors: Tsytsarev Vassiliy , Pope Daniel , Pumbo Elena , Yablonskii Alexander , Hofmann Michael
Published: March 2010

Using voltage-sensitive dye optical imaging methods, we visualized neural activity in the rat barrel cortex in response to the deflection of a single whisker in different directions. Obtained data indicates that fast movements of single whiskers in varying directions correlate with different patterns of activation in the somatosensory cortex. A functional map was created based on the voltage-sensitive dye optical signal. This supports prior research that vibrissae deflections cause responses in different cortical neurons within the barrel field according to the direction of the deflection. By analogy with the orientation columns in the visual cortex, directionally-biased single whisker responses to different directions of deflection could be a possible mechanism for the directional selectivity of this important sensory response.
Calcium‐ and polyphosphate‐containing acidocalcisomes in chicken egg yolk
Authors: Ramos Isabela B. , Miranda Kildare , Ulrich Paul , Ingram Peter , LeFurgey Ann , Machado Ednildo A. , de Souza Wanderley , Docampo Roberto
Published: March 2010

Background information. Poly P (inorganic polyphosphate) is a polymer formed by Pi residues linked by high‐energy phosphoanhydride bonds. The presence of poly P in bacteria, fungi, algae and protists has been widely recognized, but the distribution of poly P in more complex eukaryotes has been poorly studied. Poly P accumulates, together with calcium, in acidic vesicles or acidocalcisomes in a number of organisms and possesses a diverse array of functions, including roles in stress response, blood clotting, inflammation, calcification, cell proliferation and apoptosis.

Results. We report here that a considerable amount of phosphorus in the yolk of chicken eggs is in the form of poly P. DAPI (4′,6‐diamidino‐2‐phenylindole) staining showed that poly P is localized mainly in electron‐dense vesicles located inside larger vacuoles (compound organelles) that are randomly distributed in the yolk. These internal vesicles were shown to contain calcium, potassium, sodium, magnesium, phosphorus, chlorine, iron and zinc, as detected by X‐ray microanalysis and elemental mapping. These vesicles stain with the acidophilic dye Acridine Orange. The presence of poly P in organellar fractions of the egg yolk was evident in agarose gels stained with Toluidine Blue and DAPI. Of the total phosphate (Pi) of yolk organelles, 16% is present in the form of poly P. Total poly P content was not altered during the first 4 days of embryogenesis, but poly P chain length decreased after 1 day of development.

Conclusions. The results of the present study identify a novel organelle in chicken egg yolk comprising acidic vesicles with a morphology, physiology and composition similar to those of acidocalcisomes, within larger acidic vacuoles. The elemental composition of these acidocalcisomes is proportionally similar to the elemental composition of the yolk, suggesting that most of these elements are located in these organelles, which might be an important storage compartment in eggs.
Direct repression of Sonic Hedgehog expression in the stomach by Cdx2 leads to intestinal transformation
Authors: Mutoh Hiroyuki , Hayakawa Hiroko , Sashikawa Miho , Sakamoto Hirotsugu , Sugano Kentaro
Published: March 2010

Shh (Sonic Hedgehog) is a morphogen involved in gastric fundic gland differentiation in the adult. Shh expression is reduced in Helicobacter pylori-associated intestinal metaplastic change of the gastric epithelium and mice that lack Shh show intestinal transformation of the gastric mucosa. Similarly, in the stomach of Cdx2 (caudal-type homeobox 2)-transgenic mice, the gastric mucosa is replaced by intestinal metaplastic mucosa. The aim of the present study was to use Cdx2-transgenic mice to investigate: (i) Shh expression in the intestinal metaplastic mucosa of the Cdx2-transgenic mouse stomach; and (ii) the relationship between Shh and Cdx2. We determined that Shh mRNA levels were dramatically reduced in the intestinal metaplastic mucosa of the Cdx2-transgenic mouse stomach compared with the normal (wild-type) mouse stomach. This was not due to hypermethylation of the Shh promoter, but instead we showed that Cdx2 directly bound to the TATA box region of the Shh promoter. Cdx2 also down-regulated transcription of the Shh gene in the human gastric carcinoma cell lines AGS, MKN45 and MKN74. In conclusion, Cdx2 reduced Shh expression by binding to the unmethylated Shh promoter in the intestinal metaplastic mucosa of Cdx2-transgenic mouse stomach.
The glycosylphosphatidylinositol anchor is a major determinant of prion binding and replication
Authors: Bate Clive , Tayebi Mourad , Williams Alun
Published: March 2010

The prion diseases occur following the conversion of the cellular prion protein (PrPC) into an alternatively folded, disease-associated isoform (PrPSc). However, the spread of PrPSc from cell to cell is poorly understood. In the present manuscript we report that soluble PrPSc bound to and replicated within both GT1 neuronal cells and primary cortical neurons. The capacity of PrPSc to bind and replicate within cells was significantly reduced by enzymatic modification of its GPI (glycosylphosphatidylinositol) anchor. Thus PrPSc that had been digested with phosphatidylinositol-phospholipase C bound poorly to GT1 cells or cortical neurons and did not result in PrPSc formation in recipient cells. PrPSc that had been digested with phospholipase A2 (PrPSc-G-lyso-PI) bound readily to GT1 cells and cortical neurons but replicated less efficiently than mock-treated PrPSc. Whereas the addition of PrPSc increased cellular cholesterol levels and was predominantly found within lipid raft micro-domains, PrPSc-G-lyso-PI did not alter cholesterol levels and most of it was found outside lipid rafts. We conclude that the nature of the GPI anchor attached to PrPSc affected the binding of PrPSc to neurons, its localization to lipid rafts and its ability to convert endogenous PrPC.
The DNA-binding activity of mouse DNA methyltransferase 1 is regulated by phosphorylation with casein kinase 1δ/ε
Authors: Sugiyama Yasunori , Hatano Naoya , Sueyoshi Noriyuki , Suetake Isao , Tajima Shoji , Kinoshita Eiji , Kinoshita-Kikuta Emiko , Koike Tohru , Kameshita Isamu
Published: March 2010

Dnmt1 (DNA methyltansferase 1) is an enzyme that recognizes and methylates hemimethylated DNA during DNA replication to maintain methylation patterns. The N-terminal region of Dnmt1 is known to form an independent domain structure that interacts with various regulatory proteins and DNA. In the present study, we investigated protein kinases in the mouse brain that could bind and phosphorylate the N-terminal regulatory domain of Dnmt1. A protein fraction containing protein kinase activity for phosphorylation of Dnmt1(1–290) was prepared using Dnmt1(1–290)-affinity, DNA–cellulose and gel-filtration columns. When the proteins in this fraction were analysed by LC-MS/MS (liquid chromatography tandem MS), CK1δ/ε (casein kinase 1δ/ε) was the only protein kinase identified. Recombinant CK1δ/ε was found to bind to the N-terminal domain of Dnmt1 and significantly phosphorylated this domain, especially in the presence of DNA. Phosphorylation analyses using various truncation and point mutants of Dnmt1 revealed that the major priming site phosphorylated by CK1δ/ε was Ser146, and that subsequent phosphorylation at other sites may occur after phosphorylation of the priming site. When the DNA-binding activity of phosphorylated Dnmt1 was compared with that of the non-phosphorylated form, phosphorylation of Dnmt1 was found to decrease the affinity for DNA. These results suggest that CK1δ/ε binds to and phosphorylates the N-terminal domain of Dnmt1 and regulates Dnmt1 function by reducing the DNA-binding activity.
Path integral solutions for Klein–Gordon particle in vector plus scalar generalized Hulthén and Woods–Saxon potentials
Authors: Benamira F. , Guechi L. , Mameri S. , Sadoun M. A.
Published: March 2010

The Green’s function for a Klein–Gordon particle under the action of vector plus scalar deformed Hulthén and Woods–Saxon potentials is evaluated by exact path integration. Explicit path integration leads to the Green’s function for different shapes of the potentials. From the singularities of the latter Green’s function, the bound states are extracted. For q≥1 and (1/α)ln q<r<∞, the analytic expression of the energy spectrum and the normalized wave functions for the l states are obtained within the framework of an approximation to the centrifugal term. When the deformation parameter q is 0<q<1 or q<0, it is found that the quantization conditions are transcendental equations involving the hypergeometric function that require a numerical solution for the s-state energy levels. Particular cases of these potentials are also discussed briefly.
Capsule performance optimization in the National Ignition Campaign
Authors: Landen O. L. , Boehly T. R. , Bradley D. K. , Braun D. G. , Callahan D. A. , Celliers P. M. , Collins G. W. , Dewald E. L. , Divol L. , Glenzer S. H. , Hamza A. , Hicks D. G. , Hoffman N. , Izumi N. , Jones O. S. , Kirkwood R. K. , Kyrala G. A. , Michel P. , Milovich J. , Munro D. H. , Nikroo A. , Olson R. E. , Robey H. F. , Spears B. K. , Thomas C. A. , Weber S. V. , Wilson D. C. , Marinak M. M. , Suter L. J. , Hammel B. A. , Meyerhofer D. D. , Atherton J. , Edwards J. , Haan S. W. , Lindl J. D. , MacGowan B. J. , Moses E. I.
Published: March 2010

A capsule performance optimization campaign will be conducted at the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition by laser-driven hohlraums [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)]. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the OMEGA facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.
Low-loss superconducting resonant circuits using vacuum-gap-based microwave components
Authors: Cicak Katarina , Li Dale , Strong Joshua A. , Allman Michael S. , Altomare Fabio , Sirois Adam J. , Whittaker Jed D. , Teufel John D. , Simmonds Raymond W.
Published: March 2010

We have produced high-quality complex microwave circuits, such as multiplexed resonators and superconducting phase qubits, using a “vacuum-gap” technology that eliminates lossy dielectric materials. We have improved our design and fabrication strategy beyond our earlier work, leading to increased yield, enabling the realization of these complex circuits. We incorporate both novel vacuum-gap wiring crossovers for gradiometric inductors and vacuum-gap capacitors (VGC) on chip to produce resonant circuits that have large internal quality factors (30 000<QI<165 000) at 50 mK, outperforming most dielectric-filled devices. Resonators with VGCs as large as 180 pF confirm single mode behavior of our lumped-element components.
Characterization of the nontrivial and chaotic behavior that occurs in a simple city traffic model
Authors: Villalobos J. , Toledo B. A. , Pastén D. , Muñoz V. , Rogan J. , Zarama R. , Lammoglia N. , Valdivia J. A.
Published: March 2010

We explore in detail the nontrivial and chaotic behavior of the traffic model proposed by Toledo et al. [Phys. Rev. E 70, 016107 (2004)] due to the richness of behavior present in the model, in spite of the fact that it is a minimalistic representation of basic city traffic dynamics. The chaotic behavior, previously shown for a given lower bound in acceleration/brake ratio, is examined more carefully and the region in parameter space for which we observe this nontrivial behavior is found. This parameter region may be related to the high sensitivity of traffic flow that eventually leads to traffic jams. Approximate scaling laws are proposed.
Equations of state in collisionless magnetic reconnection
Authors: Le A. , Egedal J. , Fox W. , Katz N. , Vrublevskis A. , Daughton W. , Drake J. F.
Published: March 2010

Kinetic simulation as well as in situ measurement of reconnecting current sheets in the Earth’s magnetosphere show strong electron temperature anisotropy, with the parallel electron temperature becoming several times greater than the perpendicular temperature. This anisotropy is accounted for in a solution of the Vlasov equation recently derived for general reconnection geometries with magnetized electrons in the limit of fast transit time. A necessary ingredient is a magnetic field-aligned electric field extending over the ion inertial length scale. The parallel electric field maintains quasineutrality by regulating the electron density, traps a large fraction of thermal electrons, and heats electrons in the parallel direction. Based on the expression for the electron phase-space density, equations of state provide a fluid closure for the electrons that relates the parallel and perpendicular pressures to the density and magnetic field strength. The resulting fluid model agrees well with fully kinetic simulations of guide-field reconnection, accurately predicting the electron temperature anisotropy. In addition, the equations of state impose strong constraints on the electron Hall currents and magnetic fields that develop during antiparallel reconnection. The model provides scaling laws for the Hall magnetic fields and predicts the magnitude of the current in the electron layer.
A microcalorimeter for measuring heat effects of electrochemical reactions with submonolayer conversions
Authors: Etzel Kai D. , Bickel Katrin R. , Schuster Rolf
Published: March 2010

We present a microcalorimeter for measuring heat effects during electrochemical reactions with conversions down to a few percent of a monolayer, referenced to the electrode’s surface atoms. The design uses a thin pyroelectric polymer foil for temperature measurement at the backside of a thin electrode, similar to the concepts pioneered by the groups of D. A. King and Ch. T. Campbell for UHV adsorption microcalorimetry. To establish intimate thermal contact between electrode and sensor and utmost sensitivity, the free standing sensor and electrode foils are pressed together by air pressure, acting on the electrochemical cell. Pyroelectric temperature sensing is combined with pulsed electrochemistry, where the electrochemical heat is released on a time scale of about 10 ms, which is long enough for thermal equalization of the electrode-sensor assembly but short enough to avoid significant heat loss into electrolyte and cell compartment. As examples heat effects upon Ag deposition and dissolution as well as the electron transfer reaction of [Fe(CN)6]4−/[Fe(CN)6]3− are presented. The latter reaction was also employed for the calibration of the calorimeter.
The advanced helical generator
Authors: Reisman D. B. , Javedani J. B. , Ellsworth G. F. , Kuklo R. M. , Goerz D. A. , White A. D. , Tallerico L. J. , Gidding D. A. , Murphy M. J. , Chase J. B.
Published: March 2010

A high explosive pulsed power generator called the advanced helical generator (AHG) has been designed, built, and successfully tested. The AHG incorporates design principles of voltage and current management to obtain a high current and energy gain. Its design was facilitated by the use of modern modeling tools as well as high precision manufacture. The result was a first-shot success. The AHG delivered 16 MA of current and 11 MJ of energy to a quasistatic 80 nH inductive load. A current gain of 160 times was obtained with a peak exponential rise time of 20 μs. We will describe in detail the design and testing of the AHG.
Latent complexes of interstitial boron and oxygen dimers as a reason for degradation of silicon-based solar cells
Authors: Voronkov V. V. , Falster R.
Published: March 2010

Reduction in electron lifetime induced by excess electrons is a key effect in degradation of solar cells based on boron-doped and oxygen-containing silicon. Although boron related, degradation is controlled by the concentration of holes and not by the boron concentration. This recent finding is the basis for a new degradation model in which the degradation starts from a latent complex BiO2 of an interstitial boron atom and an oxygen dimer. Electron-induced reconstruction of this defect results in a production of recombination centers. This model provides a detailed explanation of the basic features of the degradation, and of subsequent recovery by annealing in the dark.
Origin of characteristics differences between top and bottom contact organic thin film transistors
Authors: Ishikawa Yoshinori , Wada Yasuo , Toyabe Toru
Published: March 2010

The differences in drain current and drain voltage (Id-Vd) characteristics of top and bottom contact organic thin film transistors (OTFTs) are analyzed by an OTFT devices simulator, which makes it possible to derive Id-Vd characteristics, potential distribution, and hole concentration distribution by solving Poisson’s equation and current continuity equation. It is found that the intrinsic characteristics of top contact devices are superior to those of the bottom contact ones, which is usually believed to be due to poor contact characteristics and poor semiconductor quality of bottom contact OTFTs. The mechanism behind the intrinsic characteristics differences is the deficiency of carriers at the source-channel interface, resulting to a very high potential drop, which the bottom contact devices suffer more. Remarkable improvements in drain current are expected by only inserting high carrier concentration region around the source/drain contact area, which totally eliminates the potential drop.
Absolute charge calibration of scintillating screens for relativistic electron detection
Authors: Buck A. , Zeil K. , Popp A. , Schmid K. , Jochmann A. , Kraft S. D. , Hidding B. , Kudyakov T. , Sears C. M. S. , Veisz L. , Karsch S. , Pawelke J. , Sauerbrey R. , Cowan T. , Krausz F. , Schramm U.
Published: March 2010

We report on new charge calibrations and linearity tests with high-dynamic range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The absolute charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/mm2. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10–100 pC/mm2 was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time absolute calibration to different experimental setups.
Nonlinear generation of large-scale magnetic fields in forced spherical shell dynamos
Authors: Livermore P. W. , Hughes D. W. , Tobias S. M.
Published: March 2010

In an earlier paper [P. W. Livermore, D. W. Hughes, and S. M. Tobias, “The role of helicity and stretching in forced kinematic dynamos in a spherical shell,” Phys. Fluids 19, 057101 (2007)], we considered the kinematic dynamo action resulting from a forced helical flow in a spherical shell. Although mean field electrodynamics suggests that the resulting magnetic field should have a significant mean (axisymmetric) component, we found no evidence for this; the dynamo action was distinctly small scale. Here we extend our investigation into the nonlinear regime in which the magnetic field reacts back on the velocity via the Lorentz force. Our main result is somewhat surprising, namely, that nonlinear effects lead to a considerable change in the structure of the magnetic field, its final state having a significant mean component. By investigating the dominant flow-field interactions, we isolate the dynamo mechanism and show schematically how the generation process differs between the kinematic and nonlinear regimes. In addition, we are able to calculate some components of the transport coefficient α and thus discuss our results within the context of mean field electrodynamics.
The FePt L1 phase transformation in thin films using multiple laser pulsing
Authors: Inaba Yuki , Thompson Gregory B. , Harrell J. W. , Klemmer Tim , Kubota Yukiko
Published: March 2010

A series of ≈12 nm thick FePt thin films deposited onto glass substrates have been annealed with multiple 1064 nm wavelength laser pulses. The fluence was varied using pulse widths of 10.0, 5.0, and 2.5 ms. The peak temperature for each individual pulse was kept near 700 °C. The A1 to L10 phase transformation was confirmed by x-ray diffraction. A single pulse was not sufficient to obtain a fully ordered state. A maximum order parameter of 0.89 and coercivity of 10.6 kOe was obtained after 5×10 ms pulses. This particular annealed film showed the greatest amount of grain growth with a mean size of 55.1 nm. This grain size is 20% smaller than that of a furnace annealed sample which was annealed for 60 s and yielded an approximately equivalent order parameter. Similar order parameters, grain sizes, and coercivity values were observed for films that had equivalent total annealing times regardless of pulse widths.
Electrical conductivity of carbon-nanotube/cellulose composite paper
Authors: Tanaka Tomo , Sano Eiichi , Imai Masanori , Akiyama Kousuke
Published: March 2010

We fabricated multiwalled carbon-nanotube/cellulose composite papers and measured their temperature dependences of electrical conductivity. The dependences were described with the Sheng’s fluctuation-induced tunneling (FIT) model. A possible mechanism of the electrical conduction in the composite paper was discussed in the context of the FIT model.
Coherent enhancement in two-photon fluorescence in molecular system induced by phase-jump modulated pulse
Authors: Zhang Shian , Zhang Hui , Yang Yan , Jia Tianqing , Wang Zugeng , Sun Zhenrong
Published: March 2010

Coherent control of two-photon fluorescence (TPF) of 2′,7′-dichlorofluorescein in methanol solution was experimentally investigated by shaping the femtosecond pulse with the phase jump. The experimental results indicated that the TPF intensity induced by the shaped femtosecond pulses with certain phase jump could be coherently enhanced. The physical mechanisms for TPF enhancement in the molecular system were explicitly discussed and analyzed, which could be attributed to the wave-packet constructive interference in the excited states. Finally, two phase-locked femtosecond pulses were used to explore the wave-packet constructive interference in the excited states of 2′,7′-dichlorofluorescein, which validate experimentally the proposed mechanism.