bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Hyperactive Transposons for Genetic Modification of Induced Pluripotent and Adult Stem Cells: A Nonviral Paradigm for Coaxed Differentiation
Authors: Belay Eyayu , Mátrai Janka , Acosta-Sanchez Abel , Ma Ling , Quattrocelli Mattia , Mátés Lajos , Sancho-Bru Pau , Geraerts Martine , Yan Bing , Vermeesch Joris , Rincón Melvin Yesid , Samara-Kuko Ermira , Ivics Zoltán , Verfaillie Catherine , Sampaolesi Maurilio , Izsvák Zsuzsanna , VandenDriessche Thierry , Chuah Marinee K. L.
Published: August 2010

Adult stem cells and induced pluripotent stem cells (iPS) hold great promise for regenerative medicine. The development of robust nonviral approaches for stem cell gene transfer would facilitate functional studies and potential clinical applications. We have previously generated hyperactive transposases derived from Sleeping Beauty, using an in vitro molecular evolution and selection paradigm. We now demonstrate that these hyperactive transposases resulted in superior gene transfer efficiencies and expression in mesenchymal and muscle stem/progenitor cells, consistent with higher expression levels of therapeutically relevant proteins including coagulation factor IX. Their differentiation potential and karyotype was not affected. Moreover, stable transposition could also be achieved in iPS, which retained their ability to differentiate along neuronal, cardiac, and hepatic lineages without causing cytogenetic abnormalities. Most importantly, transposon-mediated delivery of the myogenic PAX3 transcription factor into iPS coaxed their differentiation into MYOD+ myogenic progenitors and multinucleated myofibers, suggesting that PAX3 may serve as a myogenic “molecular switch” in iPS. Hence, this hyperactive transposon system represents an attractive nonviral gene transfer platform with broad implications for regenerative medicine, cell and gene therapy.
Hand‐raising a spectral tarsier (Tarsius tarsier) at the Ueno Zoological Gardens
Authors: Hirota Atsushi , Hara Tatsuko , Hosoda Takahisa , Hashizaki Fumitaka
Published: August 2010

On February 10, 2008, a newborn male spectral tarsier (Tarsius tarsier) was found on the floor of the indoor exhibit room in the Small Mammal House of the Ueno Zoological Gardens. The dam showed no signs of providing maternal care and therefore we decided to hand‐raise the infant. Its birth weight was 18.7 g. We placed the dam and infant in an incubator and gave 12.5–25% formula (for kittens), until the 145th day after birth. We limited the volume of formula intake to avoid excessive intake and to prevent diarrhea. For nutrition enrichment, we added a chicken liver homogenate to the formula 1–3 times per day. The infant was given a sunbath for 10 min on the 28th day. He showed no serious decline in health, except for diarrhea that occurred during the first few days after birth. He ate a small cricket for the first time on the 50th day and easily caught mealworms on his own on the 105th day. Gradual changes in feeding times, formula concentration, and the nutritionally enriched formula were essential for successfully hand‐raising the tarsier. Zoo Biol 30:218–224, 2011. © 2010 Wiley‐Liss, Inc.
DOES CROP-LIVESTOCK INTEGRATION LEAD TO IMPROVED CROP PRODUCTION IN THE SAVANNA OF WEST AFRICA?
Authors: FRANKE A. C. , BERKHOUT E. D. , IWUAFOR E. N. O. , NZIGUHEBA G. , DERCON G. , VANDEPLAS I. , DIELS J.
Published: August 2010

Integrated crop-livestock farming in the Guinea savanna of West Africa is often assumed to lead to synergies between crop and livestock production, thereby improving the overall productivity and resilience of agricultural production. Whether these synergies actually occur remains poorly studied. On-farm trials were conducted in northern Nigeria over a period of four years to assess the agronomic and economic performance of maize-legume systems with and without the integration of livestock (goats). Groundnut-maize rotations with livestock achieved the highest carry-over of nutrients as manure from one season to the next, covering approximately one-third of the expected N, P and K uptake by maize and reducing the demand for synthetic fertilizers. However, the advantage of lower fertilizer costs in rotations with livestock was offset by higher labour costs for manure application and slightly lower values of maize grain. Overall, no clear agronomic or economic benefits for crop production were observed from the combined application of manure and synthetic fertilizer over the application of synthetic fertilizer only, probably because the amounts of manure applied were relatively small. Legume-maize rotations achieved higher cereal yields, a better response to labour and fertilizer inputs, and a higher profitability than maize-based systems with no or only a small legume component, irrespective of the presence of livestock. Livestock at or near the farm could nevertheless make legume cultivation economically more attractive by increasing the value of legume haulms. The results suggested that factors other than crop benefits, e.g. livestock providing tangible and non-tangible benefits and opportunities for animal traction, could be important drivers for the ongoing integration of crop and livestock production in the savanna.
WILLIAM A. WILLIAMS'S TRAGEDY FIFTY YEARS ON
Authors: KAMPMARK BINOY
Published: August 2010

Fifty years have passed since the publication of The tragedy of American Diplomacy, the seminal work by New Left scholar William Appleman Williams. The work fired off one of the most important salvos of historical revisionism, heralding the arrival of the ‘Wisconsin School’ of American historiography. In examining the expansionist and consuming tendencies of American power and capital, Williams ushered in a movement which has left an enduring mark. Despite attacks on its credibility and an assortment of drawbacks, Tragedy remains a strong antidote to triumphalist narratives of American history, and pressingly important in the current political climate.
PRINTED QUESTIONNAIRES, RESEARCH NETWORKS, AND THE DISCOVERY OF THE BRITISH ISLES, 1650–1800
Authors: FOX ADAM
Published: August 2010

This article examines the circulation of printed questionnaires as a research strategy among those investigating the constituent parts of the British Isles between the mid-seventeenth and late eighteenth centuries. It traces the origins and development of published ‘heads’ or ‘articles of enquiry’ as a means of acquiring information on antiquities, geography, and natural history and pieces together the research networks through which this methodology was shared and elaborated. The learned societies, ecclesiastical infrastructure, and periodical publications of the day are shown to have been instrumental in promoting this practice and in forging links between scholars and the ‘learned and ingenious’ in the parishes to whom such ‘queries’ were addressed. It is argued that these questionnaires were an important and insufficiently appreciated aspect of regional studies during the period. Though the responses to them are shown to have been highly variable, both in quantity and quality, it is suggested that they helped to establish what has become an important technique of data collection in modern academic inquiry.
LEISURE AND THE USE OF DOMESTIC SPACE IN GEORGIAN LONDON
Authors: HELLER BENJAMIN
Published: August 2010

This article examines leisure in eighteenth-century London and argues that historians have exaggerated the importance of public, commercial leisure at the expense of leisure in the home. The domestic sphere was the primary scene of leisure for men and women of propertied society. In tandem with this examination of leisure I argue that our frameworks for understanding the use of domestic space fail to capture both the significance of particular rooms and the variety of uses for individual rooms. The failings of the public/private framework are well known, but scholars have thus far failed to develop successful alternatives. From diaries, letters, and inventories conclusions may be drawn about the habitual uses of space, but letters and diaries also provide evidence of how room use varied depending on time of day, activities pursued or people undertaking those activities. I present several variables that residents used to determine where and with whom different activities were taken. Meanings of spaces were contingent upon a mix of qualities constantly re-assessed by residents and guests.
HANNAH LAWRANCE AND THE CLAIMS OF WOMEN'S HISTORY IN NINETEENTH-CENTURY ENGLAND
Authors: DABBY BENJAMIN
Published: August 2010

The historian, Hannah Lawrance (1795–1875), played an important role in nineteenth-century public debate about women's education. Like Catharine Macaulay and Mary Wollstonecraft, she argued that virtue had no sex and she promoted the broad education of women in order to increase their opportunities for employment. But unlike her bluestocking predecessors, she derived her argument from a scholarly reappraisal of women's history. Whereas the Strickland sisters' Tory Romantic histories celebrated the Tudor and Stuart eras in particular, Lawrance's ‘olden time’ celebrated the medieval period. This is when she located England's civilizational progress, driven by the education of queens and the wider state of women's education, allowing her to evade the potential conflict of a feminine creature in a manly role. Using the condition of women to measure the peaks and troughs of civilization was a familiar approach to historical writing, but Lawrance's radical argument was that women were often responsible for England's progress, rather than passive bystanders. Her emphasis on women's contribution to public life complemented the Whig-nationalist narrative and secured her a high reputation across a range of political periodicals. Above all, it appealed to other liberal reformers such as Thomas Hood, Charles Wentworth Dilke, and Robert Vaughan, who shared Lawrance's commitment to social reform and helped to secure a wide audience for her historical perspective.
Mean flow deformation in a laminar separation bubble: separation and stability characteristics
Authors: MARXEN OLAF , RIST ULRICH
Published: August 2010

The mutual interaction of laminar–turbulent transition and mean flow evolution is studied in a pressure-induced laminar separation bubble on a flat plate. The flat-plate boundary layer is subjected to a sufficiently strong adverse pressure gradient that a separation bubble develops. Upstream of the bubble a small-amplitude disturbance is introduced which causes transition. Downstream of transition, the mean flow strongly changes and, due to viscous–inviscid interaction, the overall pressure distribution is changed as well. As a consequence, the mean flow also changes upstream of the transition location. The difference in the mean flow between the forced and the unforced flows is denoted the mean flow deformation. Two different effects are caused by the mean flow deformation in the upstream, laminar part: a reduction of the size of the separation region and a stabilization of the flow with respect to small, linear perturbations. By carrying out numerical simulations based on the original base flow and the time-averaged deformed base flow, we are able to distinguish between direct and indirect nonlinear effects. Direct effects are caused by the quadratic nonlinearity of the Navier–Stokes equations, are associated with the generation of higher harmonics and are predominantly local. In contrast, the stabilization of the flow is an indirect effect, because it is independent of the Reynolds stress terms in the laminar region and is solely governed by the non-local alteration of the mean flow via the pressure.
Magnetic electron-drift vortex modes in an inhomogeneous quantum plasma
Authors: NAEEM ISMAT , MIRZA ARSHAD M. , MASOOD W. , FARID T.
Published: August 2010

Dispersion relation for the low-frequency magnetic electron-drift vortex (MEDV) mode in an inhomogeneous dense quantum plasma has been derived. New class of purely growing instabilities are found to exist on a time scale of the order of ion plasma period. We found that the MEDV mode become unstable when the propagation direction is perpendicular to the equilibrium density gradients. We believe that the present investigation would be useful to understand the wave phenomena and in the study of magnetic field generation in laser-produced plasmas as well as in dense space plasmas, where quantum effects are expected to play a dominant role.
Tribute to Professor Tito Mendonça on the occasion of his 65th birthday
Authors: VARANDAS C.
Published: August 2010

It is with great pleasure that I write this modest and very personal tribute for the current volume of the Journal of Plasma Physics dedicated to honor Professor José Tito da Luz Mendonça on the occasion of his 65th birthday. Modest because, most probably, I will not have enough expertise to summarize an outstanding and truly impressive career of more than 40 years in a short text. Very personal since this contribution is based on my knowledge acquired during more than 25 years of joint work at Instituto Superior Técnico (IST).
Preface
Authors: SILVA LUIS O. , BINGHAM ROBERT , MARKLUND MATTIAS , SHUKLA PADMA K. , TRINES RAOUL
Published: August 2010

It is a great honor and pleasure to dedicate this special issue of Journal of Plasma Physics to our dear friend and colleague Professor Tito Mendonça on the occasion of his 65th birthday on December 28, 2010. Professor Tito is one of the most inspiring scientists in plasma physics, with contributions touching many other fields, using cross-cutting methodologies and novel theoretical techniques, which have led to important contributions and insights. Moreover, he has inspired many students at the Instituto Superior Técnico in Lisbon and mentored a new generation of physicists in Portugal to pursue scientific careers in a wide spectrum of fields from plasma physics to nonlinear optics, from astrophysics to quantum optics.
On the quantum space–time structure of light
Authors: GUERREIRO A.
Published: August 2010

We extend the quantum theory of Time Refraction for a generic spatial and temporal modulation of the optical properties of a medium, such as a dielectric or a gravitational field. The derivation of the local Bogoliubov transformations relating the global electromagnetic modes (valid over the entire span of space and time) with the local modes (valid for the vicinity of each spatial and temporal position) is presented and used in the evaluation of vacuum photon creation by the optical modulations of the medium. We use this approach to relate and review the results of different quantum effects such as the dynamical Casimir effect, space and Time Refraction, the Unruh effect and radiation from superluminal non-accelerated optical boundaries.
Instability of plasma waves caused by incoherent photons in dense plasmas
Authors: SHUKLA P. K. , STENFLO L. , BINGHAM R.
Published: August 2010

We consider the nonlinear instability of modified Langmuir and ion–sound waves caused by partially coherent photons in dense quantum plasmas. In our model, the dynamics of the photons is governed by a wave kinetic equation. The evolution equations for the Langmuir and ion–sound waves are deduced from the quantum hydrodynamic equations accounting for the incoherent photon pressure, the quantum statistical electron pressure, and the quantum Bohm force acting on the degenerate electrons. The governing equations are Fourier analyzed to obtain nonlinear dispersion relations. The latter are analyzed to predict instability of the modified Langmuir and ion–sound waves in the presence of partially coherent photons. Possible applications of our investigation to the next generation of intense laser–solid dense plasma experiments and compact dense astrophysical bodies are mentioned.
Housing Concerns of Vulnerable Older Canadians
Authors: Weeks Lori E. , LeBlanc Kristal
Published: August 2010

La préparation pour les besoins futurs de logement des personnes âgées est impérative dans les pays avec des populations vieillissantes, mais peu est connu sur ces questions parmi les adultes plus âgés vulnérables. Cette étude a utilisé une approche qualitative pour identifier les préoccupations majeures au sujet de logement dans ce groupe. Un total de 84 personnes âgées vulnérables, y compris des personnes agées indigènes souffrant de divers handicaps et des minorités ethniques ont participé en 10 groupes de discussion. Les normes de besoins de logement de la Société canadienne d’hypothèques et de logement (SCHL) ont offert un cadre d’analyse de données de base, avec l’identification des thèmes de logement clés supplémentaires entre et au sein de groupes des personnes âgées vulnérables. Les résultats fournissent un aperçu sur les caractéristiques de logement préféré, indépendamment de la forme de logement. En outre, les résultats fournissent un aperçu de comment prendre en charge les adultes âgés vulnérables qui choisissent de rester dans leurs maisons et leurs communautés, et comment garantir que logement approprié est développé qui répond aux besoins de cette population diversifiée.
Effects of plasma sheet properties on storm‐time ring current
Authors: Zheng Yihua , Lui Anthony T. Y. , Fok Mei‐Ching
Published: August 2010

Using an electrically self‐consistent kinetic ring current model, we investigate how different conditions of plasma sheet distribution affect the ring current properties. Results include comparative studies in (1) varying the radial distance of the plasma sheet boundary; (2) varying local time distribution of the source population; (3) varying the source spectra, with #2 as our main focus. Our results show that a source that is farther away from Earth leads to a stronger ring current than a source that is closer to the Earth. Local time distribution of the source plays an important role in determining both the radial and azimuthal (local time) location of the ring current peak pressure. We found that postmidnight source locations generally lead to a stronger ring current. This finding is in agreement with Lavraud et al. (2008). However, our results do not exhibit any simple dependence of the local time distribution of the peak ring current (within the lower energy range) on the local time distribution of the source, as suggested by Lavraud et al. (2008). Instead, the local time distribution of source populations has to compete with the dynamically updated self‐consistent electric field (through the coupling to the ionosphere) in controlling the ring current intensity and peak location. Our results also show that different source spectra lead to different (though the difference may not be very significant) ring current intensities and that low‐energy plasma in the kiloelectron volt range at the boundary constitutes a dominant source population to the ring current. In addition, we found that the radial location of source population is also important to ring current development.
Longitudinal and geomagnetic activity modulation of the equatorial thermosphere anomaly
Authors: Lei Jiuhou , Thayer Jeffrey P. , Forbes Jeffrey M.
Published: August 2010

In this paper we examine the detailed similarities and differences between the equatorial thermosphere anomaly (ETA) and the equatorial ionization anomaly (EIA) from 20 March to 6 April 2002, when both the ETA and the EIA are distinct in the Challenging Minisatellite Payload (CHAMP) observations. The characteristics of the ETA and the EIA are obtained from the CHAMP accelerometer, in situ electron density measurements, and total electron content (TEC) above the CHAMP satellite. Our results show that the trough locations of the ETA and the EIA in latitude show a good agreement, and both correspond well with the dip magnetic equator, while the ETA crests are usually located poleward of the EIA. Meanwhile, the latitudinal locations of the ETA crests exhibit strong hemispheric asymmetry and large variability during our study interval. The longitudinal variations between the EIA and the ETA show significant differences. The EIA crests from the CHAMP observations show strong wave 4 structures, but the primary component in the ETA is wave 1. Moreover, the ETA densities show strong variations in response to geomagnetic activity, whereas CHAMP in situ electron densities and TEC at the EIA do not reflect such large day‐to‐day variability. Therefore, a simple EIA‐ETA relationship cannot explain the dependence of the longitudinal and geomagnetic activity modulation of the ETA and the EIA. The meridional ion drag, which is significantly modulated by enhanced equatorward winds during elevated geomagnetic activity, is probably responsible for some of the observed features in the ETA, although no unambiguous explanation for ETA formation yet exists.
Tidal waves in the polar lower thermosphere observed using the EISCAT long run data set obtained in September 2005
Authors: Nozawa S. , Ogawa Y. , Oyama S. , Fujiwara H. , Tsuda T. , Brekke A. , Hall C. M. , Murayama Y. , Kawamura S. , Miyaoka H. , Fujii R.
Published: August 2010

Characteristics are presented of the lower thermospheric wind from a long run data set obtained by the EISCAT UHF radar at Tromsø (69.6°N, 19.2°E) over ∼23 days, from September 6 to 29, 2005. The derived semidiurnal amplitude exhibited day‐to‐day variations (∼5–30 ms−1) at and above 109 km, while the phase varied little with the day. We have found a mode change of the semidiurnal tide occurring during September 17–22, 2005. Between September 6 and 16, the vertical wavelengths were estimated to be ∼58 km and ∼76 km for the meridional and zonal components, respectively, while between September 23 and 29, they became less than ∼24 km. The day to day variability of the diurnal tide was less obvious than that of the semidiurnal tide. The diurnal amplitude of the meridional component increased with height except for 8 days between September 13 and 20, when the diurnal amplitudes were smaller values (<40 ms−1) at and above 111 km than those for the other intervals. Furthermore, the shapes of the altitude profiles of the meridional phase differ from those for the other intervals. We have evaluated contributions due to the electric field and the ion drag acceleration and showed that they were not the causes. From the analysis of 22.5 days of wind data, we found about 5–6 day oscillations in the lower thermosphere, probably where there were planetary wave activities in the lower thermosphere.
Deposition velocity of ultrafine particles measured with the Eddy‐Correlation Method over the Nansen Ice Sheet (Antarctica)
Authors: Contini D. , Donateo A. , Belosi F. , Grasso F. M. , Santachiara G. , Prodi F.
Published: August 2010

This work reports an analysis of the concentration, size distribution, and deposition velocity of atmospheric particles over snow and iced surfaces on the Nansen Ice Sheet (Antarctica). Measurements were performed using the eddy‐correlation method at a remote site during the XXII Italian expedition of the National Research Program in Antarctica (PNRA) in 2006. The measurement system was based on a condensation particle counter (CPC) able to measure particles down to 9 nm in diameter with a 50% efficiency and a Differential Mobility Particle Sizer for evaluating particle size distributions from 11 to 521 nm diameter in 39 channels. A method based on postprocessing with digital filters was developed to take into account the effect of the slow time response of the CPC. The average number concentration was 1338 cm−3 (median, 978 cm−3; interquartile range, 435–1854 cm−3). Higher concentrations were observed at low wind velocities. Results gave an average deposition velocity of 0.47 mm/s (median, 0.19 mm/s; interquartile range, −0.21 −0.88 mm/s). Deposition increased with the friction velocity and was on average 0.86 mm/s during katabatic wind characterized by velocities higher than 4 m/s. Observed size distributions generally presented two distinct modes, the first at approximately 15–20 nm and the second (representing on average 70% of the total particles) at 60–70 nm. Under strong‐wind conditions, the second mode dominated the average size distribution.
A new mobile‐immobile model for reactive solute transport with scale‐dependent dispersion
Authors: Gao Guangyao , Zhan Hongbin , Feng Shaoyuan , Fu Bojie , Ma Ying , Huang Guanhua
Published: August 2010

This study proposed a new mobile‐immobile model (MIM) to describe reactive solute transport with scale‐dependent dispersion in heterogeneous porous media. The model was derived from the conventional MIM but assumed the dispersivity to be a linear or exponential function of travel distance. The linear adsorption and the first‐order degradation of solute were also considered in the model. The Laplace transform technique and the de Hoog numerical Laplace inversion method were applied to solve the developed model. Solute breakthrough curves (BTCs) obtained from MIM with scale‐dependent and constant dispersions were compared, and a constant effective dispersivity was provided to reflect the lumped scale‐dependent dispersion effect. The effective dispersivity was calculated by arithmetically averaging the distance‐dependent dispersivity. With this effective dispersivity, MIM could produce similar BTC as that from MIM with scale‐dependent dispersion in porous media with moderate heterogeneity. The applicability of the proposed new model was tested with concentration data from a 1,250‐cm long and highly heterogeneous soil column. The simulation results indicated that MIM with constant and linear distance‐dependent dispersivities were unable to adequately describe the measured BTCs in the column, while MIM with exponential distance‐dependent dispersivity satisfactorily captured the evolution of BTCs.
Boron and magnesium isotopic composition of seawater
Authors: Foster G. L. , Pogge von Strandmann P. A. E. , Rae J. W. B.
Published: August 2010

The isotopic systems of boron and magnesium are increasingly being used as proxies for a number of environmental variables and processes. The isotopic composition of seawater for both systems plays a central role in these studies and is an important interlaboratory standard. Given the long residence times of both elements (∼107 years) it is commonly assumed that seawater is isotopically homogenous for these systems, yet no systematic studies currently exist. Here we present the B and Mg isotopic composition of 26–28 seawater samples from a number of ocean basins that encompass a significant range in salinity (32 to 38 psu), temperature (−0.3 to +25.9°C) and water depth (0 to 1240 m). We find no significant or systematic variation for either system in accordance with their long residence times. We recommend that the mean values we report (δ11B = 39.61 ± 0.04 ‰ (2 s.e.; n = 28), δ25Mg = −0.43 ± 0.01 ‰ (2 s.e.; n = 26), δ26Mg = −0.82 ± 0.01 ‰ (2 s.e.; n = 26)) be used in future studies involving Mg and B isotopes.
Applications of XPS to the study of inorganic compounds
Authors: Wilson Karen , Lee Adam
Published: August 2010

The surface behaviour of materials is crucial to our everyday lives. Studies of the corrosive, reactive, optical and electronic properties of surfaces are thus of great importance to a wide range of industries including the chemical and electronics sectors. The surface properties of polymers can also be tuned for use in packaging, non stick coatings or for use in medical applications. Methods to characterise surface composition and reactivity are thus critical to the development of next generation materials. This report will outline the basic principles of X-ray photoelectron spectroscopy and how it can be applied to analyse the surfaces of inorganic materials. The role of XPS in understanding the nature of the active site in heterogeneous catalysts will also be discussed.
At the heart of tissue: endothelin system and end-organ damage
Authors: Iglarz Marc , Clozel Martine
Published: August 2010

ET (endothelin)-1 was first described as a potent vasoconstrictor. Since then, many other deleterious properties mediated via its two receptors, ETA and ETB, have been described, such as inflammation, fibrosis and hyperplasia. These effects, combined with a wide tissue distribution of the ET system, its up-regulation in pathological situations and a local autocrine/paracrine activity due to a high tissue receptor binding, make the tissue ET system a key local player in end-organ damage. Furthermore, ET-1 interacts in tissues with other systems such as the RAAS (renin–angiotensin–aldosterone system) to exert its effects. In numerous genetically modified animal models, non-specific or organ-targeted ET-1 overexpression causes intense organ damage, especially hypertrophy and fibrosis, in the absence of haemodynamic changes, confirming a local activity of the ET system. ET receptor antagonists have been shown to prevent and sometimes reverse these tissue alterations in an organ-specific manner, leading to long-term benefits and an improvement in survival in different animal models. Potential for such benefits going beyond a pure haemodynamic effect have also been suggested by clinical trial results in which ET receptor antagonism decreased the occurrence of new digital ulcers in patients with systemic sclerosis and delayed the time to clinical worsening in patients with PAH (pulmonary arterial hypertension). The tissue ET system allows therapeutic interventions to provide organ selectivity and beneficial effects in diseases associated with tissue inflammation, hypertrophy or fibrosis.
Geometric phases in astigmatic optical modes of arbitrary order
Authors: Habraken Steven J. M. , Nienhuis Gerard
Published: August 2010

The transverse spatial structure of a paraxial beam of light is fully characterized by a set of parameters that vary only slowly under free propagation. They specify bosonic ladder operators that connect modes of different orders, in analogy to the ladder operators connecting harmonic-oscillator wave functions. The parameter spaces underlying sets of higher-order modes are isomorphic to the parameter space of the ladder operators. We study the geometry of this space and the geometric phase that arises from it. This phase constitutes the ultimate generalization of the Gouy phase in paraxial wave optics. It reduces to the ordinary Gouy phase and the geometric phase of nonastigmatic optical modes with orbital angular momentum in limiting cases. We briefly discuss the well-known analogy between geometric phases and the Aharonov–Bohm effect, which provides some complementary insights into the geometric nature and origin of the generalized Gouy phase shift. Our method also applies to the quantum-mechanical description of wave packets. It allows for obtaining complete sets of normalized solutions of the Schrödinger equation. Cyclic transformations of such wave packets give rise to a phase shift, which has a geometric interpretation in terms of the other degrees of freedom involved.
Rigid symmetries and conservation laws in non-Lagrangian field theory
Authors: Kaparulin D. S. , Lyakhovich S. L. , Sharapov A. A.
Published: August 2010

Making use of the Lagrange anchor construction introduced earlier to quantize non-Lagrangian field theories, we extend the Noether theorem beyond the class of variational dynamics.
Possible quantum kinematics. II. Nonminimal case
Authors: Gromov N. A.
Published: August 2010

The quantum analogs of the N-dimensional Cayley–Klein spaces with different combinations of quantum and Cayley–Klein structures are described for nonminimal multipliers, which include the first and the second powers of contraction parameters in the transformation of deformation parameter. The noncommutative analogs of (N−1)-dimensional constant curvature spaces are introduced. Part of these spaces for N=5 are interpreted as the noncommutative analogs of (1+3) space-time models. As a result the wide variety of the quantum deformations of realistic kinematics are suggested.
Classification of indecomposable modules of the intermediate series over the twisted N=2 superconformal algebra
Authors: Li Junbo , Su Yucai , Zhu Linsheng
Published: August 2010

In this paper, a classification of indecomposable modules of the intermediate series over the twisted N=2 superconformal algebra is obtained.
Finite-gap solutions of 2+1 dimensional integrable nonlinear evolution equations generated by the Neumann systems
Authors: Chen Jinbing
Published: August 2010

Each soliton equation in the Korteweg–de Vries (KdV) hierarchy, the 2+1 dimensional breaking soliton equation, and the 2+1 dimensional Caudrey–Dodd–Gibbon–Kotera–Sawada (CDGKS) equation are reduced to two or three Neumann systems on the tangent bundle TSN−1 of the unit sphere SN−1. The Lax–Moser matrix for the Neumann systems of degree N−1 is deduced in view of the Mckean–Trubowitz identity and a bilinear generating function, whose favorite characteristic accounts for the problem of the genus of Riemann surface matching to the number of elliptic variables. From the Lax–Moser matrix, the constrained Hamiltonians in the sense of Dirac–Poisson bracket for all the Neumann systems are written down in a uniform recursively determined by integrals of motion. The involution of integrals of motion and constrained Hamiltonians is completed on TSN−1 by using a Lax equation and their functional independence is displayed over a dense open subset of TSN−1 by a direct calculation, which contribute to the Liouville integrability of a family of Neumann systems in a new systematical way. We also construct the hyperelliptic curve of Riemann surface and the Abel map straightening out the restricted Neumann flows that naturally leads to the Jacobi inversion problem on the Jacobian with the aid of the holomorphic differentials, from which some finite-gap solutions expressed by Riemann theta functions for the 2+1 dimensional breaking soliton equation, the 2+1 dimensional CDGKS equation, the KdV, and the fifth-order KdV equations are presented by means of the Riemann theorem.
A study on the modulation of the electrical transport by mechanical straining of individual titanium dioxide nanotube
Authors: Asthana A. , Shokuhfar T. , Gao Q. , Heiden P. , Friedrich C. , Yassar R. S.
Published: August 2010

We report here, the deformation driven modulation of the electrical transport properties of an individual TiO2 nanotube via in situ transmission electron microscopy (TEM) using a scanning tunneling microscopy system. The current-voltage characteristics of each individual TiO2 nanotube revealed that under bending deformation within the elastic limit, the electrical conductivity of a TiO2 nanotube can be enhanced. High resolution TEM and electron diffraction pattern reveal that TiO2 nanotubes have tetragonal structure (a=0.378 nm, c=0.9513 nm, I41/amd). Analysis based on a metal-semiconductor-metal model suggests that in-shell, surface defect-driven conduction modes and electron–phonon coupling effect are responsible for the modulated semiconducting behaviors.
Resonant enhancement transmission in a Ge subwavelength periodic membrane
Authors: Sang Tian , Wang Zhanshan , Zhou Xun , Cai Shaohong
Published: August 2010

In this letter, the effect of resonant enhancement transmission in a Ge subwavelength periodic membrane is presented. The key idea is that the strong refractive-index modulation of the Ge subwavelength periodic membrane can support the excitation of three leaky mode resonances TE1,1, TE2,1, and TE3,0 in a reflection band, and every leaky mode resonance relates a transmission peak on its edge, thus the overlapping of the edges of these multiple leaky mode resonances can be tailored to create resonant enhancement transmission. Resonant enhancement transmission with single and double channels near λ=10.60 μm is designed to demonstrate this concept.
Dynamics of glass-forming liquids. XIV. A search for ultraslow dielectric relaxation in glycerol
Authors: Richert Ranko
Published: August 2010

A recent dielectric study of various polyalcohols reported on the general occurrence of an ultraslow process with Debye type character in hydrogen bonded liquids [R. Bergman, H. Jansson, and J. Swenson, J. Chem. Phys. 132, 044504 (2010)], whereas previous work suggested that such behavior is specific to monoalcohols only. Clarifying this issue is highly relevant for assessing models aimed at rationalizing these modes that are slower than the primary structural relaxation and associated with a single time constant. To this end, the dielectric relaxation of glycerol is measured at different electrode distances with high accuracy. In this manner, electrode polarization can be separated from the dielectric signals intrinsic in the supercooled liquid. In the frequency range below the loss peak frequency ωmax of the α-process, only dc-conductivity is required to understand the dielectric properties of supercooled glycerol within a margin of ε″≈±0.1 and thus no indication of an ultraslow peak is found. More quantitatively, any dielectric Debye like mode located around 10−5ωmax would need to have an amplitude smaller than 0.4% of that of the primary dielectric process to be consistent with the present findings, in contrast to previous claims of >50%.
Electronic properties of the high electron mobility Al0.56In0.44Sb/Ga0.5In0.5Sb heterostructure
Authors: Desplanque L. , Vignaud D. , Godey S. , Cadio E. , Plissard S. , Wallart X. , Liu P. , Sellier H.
Published: August 2010

Electronic properties of the Al0.56In0.44Sb/Ga0.5In0.5Sb heterostructure grown by molecular beam epitaxy are investigated. We measure by means of x-ray photoemission spectroscopy, photoluminescence, and Hall effect measurements the key parameters involved in the achievement of a high speed and very low power consumption field effect transistor: conduction and valence band offsets, energy gaps of channel and barrier materials, electron effective mass, and density of states in the channel. We observe the influence of the quantum well thickness on the electron Hall mobility and sheet carrier density. A type I heterostructure exhibiting a room temperature electron mobility of 25 000 cm2 V−1 s−1 with a sheet carrier density of 1.5×1012 cm−2 is demonstrated for the widest channel. We show that the thickness of the channel influences both Hall density and mobility through a multisubband occupancy. We discuss about the scattering mechanisms limiting the mobility in the second subband.
Molecular beam epitaxy of N-polar InGaN
Authors: Nath Digbijoy N. , Gür Emre , Ringel Steven A. , Rajan Siddharth
Published: August 2010

We report on the growth of N-polar InxGa1−xN by N2 plasma-assisted molecular beam epitaxy. Ga-polar and N-polar InGaN films were grown at different growth temperatures and the composition was estimated by photoluminescence (PL) measurements. A growth model that incorporates the incoming and desorbing atomic fluxes is proposed to explain the compositional dependence of InGaN on the flux of incoming atomic species and growth temperature. The growth model is found to be in agreement with the experimental data. The peak PL intensity for N-face samples is found to exhibit a two order of magnitude increase for a 100 °C increase in growth temperature. Besides, at 600 nm, the N-face sample shows more than 100 times higher PL intensity than Ga-face sample at comparable wavelengths indicating its superior optical quality. The understanding of growth kinetics of InGaN presented here will guide the growth of N-polar InGaN in a wide range of growth temperatures.
Modeling the sustained release of lipophilic drugs from liposomes
Authors: Zeng Like , Wu Xiaoyi
Published: August 2010

The bilayered structure of liposomes enables the encapsulation of lipophilic drugs in their lipid bilayers and water-soluble molecules in the interior aqueous compartments. We develop a convection-driven drug release model that considers the structural characteristics of liposomes and reversible drug-lipid interaction. An analytical solution to the model is obtained. The solution agrees well with experimental data on the sustained release of lipophilic anticancer drugs from liposomes. The model provides a useful tool for the rational design of liposomal drug delivery systems.
Photoinduced nonlinear refraction in a polymeric film encapsulating a bacteriorhodopsin mutant
Authors: Teng Xue-lei , Lu Ming , Zhao You-yuan , Ma De-wang , Zhao Ying-chun , Ding Jian-dong , Huang Wei-da
Published: August 2010

The absorption change versus time after switching off the illumination on a polymeric film that contained a bacteriorhodopsin (BR) mutant has been measured. The M-lifetime of this BR mutant is ∼320 s. A pertinent Z-scan was performed to study the BR optical nonlinearity. A physical model with multi-level transitions in the Z-scan was suggested. The minimum saturated light intensity measured at 633 nm is ∼0.9 mW/cm2. A low intensity of 70 μW/cm2 has been used for recording in this film. The change in refraction index Δn633 is −3.0×10−3 and Δn476 is 8.5×10−3 with the intensity all at ∼100 mW/cm2.
Mechanisms of complex morphological evolution during solid-state dewetting of single-crystal nickel thin films
Authors: Ye Jongpil , Thompson Carl V.
Published: August 2010

We report studies of complex morphological evolution during solid-state dewetting of 120 nm thick single-crystal Ni(100) and Ni(110) thin films on MgO(100) and MgO(110) substrates. During dewetting, holes that form in the Ni films evolve to complex shapes that depend on the crystallographic orientation of the films and annealing ambient. We characterize the origins of hole, line, and particle morphologies that develop during the dewetting process, and identify a sequence of instabilities that control the morphological evolution. This study provides mechanistic insights for control of dewetting to produce specific ordered structures.
Highly sensitive terahertz measurement of layer thickness using a two-cylinder waveguide sensor
Authors: Theuer M. , Beigang R. , Grischkowsky D.
Published: August 2010

We report on the layer thickness determination on dielectrically coated metal cylinders using terahertz (THz) time-domain spectroscopy. A considerable sensitivity increase of up to a factor of 150 is obtained for layers down to 2.5 μm thickness by introducing an experimental geometry based on a two-cylinder waveguide sensor. The layer attached on one metal cylinder is guided in contact with the second metal cylinder in the THz beam waist. This approach uses concepts of adiabatic THz wave compression and the advantages of THz waveguides. The results are compared to measurements on free-standing layers.
Targeting the voltage sensor of Kv7.2 voltage-gated K
+
channels with a new gating-modifier
Authors: Peretz Asher , Pell Liat , Gofman Yana , Haitin Yoni , Shamgar Liora , Patrich Eti , Kornilov Polina , Gourgy-Hacohen Orit , Ben-Tal Nir , Attali Bernard
Published: August 2010

The pore and gate regions of voltage-gated cation channels have been often targeted with drugs acting as channel modulators. In contrast, the voltage-sensing domain (VSD) was practically not exploited for therapeutic purposes, although it is the target of various toxins. We recently designed unique diphenylamine carboxylates that are powerful Kv7.2 voltage-gated K
+
channel openers or blockers. Here we show that a unique Kv7.2 channel opener, NH29, acts as a nontoxin gating modifier. NH29 increases Kv7.2 currents, thereby producing a hyperpolarizing shift of the activation curve and slowing both activation and deactivation kinetics. In neurons, the opener depresses evoked spike discharges. NH29 dampens hippocampal glutamate and GABA release, thereby inhibiting excitatory and inhibitory postsynaptic currents. Mutagenesis and modeling data suggest that in Kv7.2, NH29 docks to the external groove formed by the interface of helices S1, S2, and S4 in a way that stabilizes the interaction between two conserved charged residues in S2 and S4, known to interact electrostatically, in the open state of Kv channels. Results indicate that NH29 may operate via a voltage-sensor trapping mechanism similar to that suggested for scorpion and sea-anemone toxins. Reflecting the promiscuous nature of the VSD, NH29 is also a potent blocker of TRPV1 channels, a feature similar to that of tarantula toxins. Our data provide a structural framework for designing unique gating-modifiers targeted to the VSD of voltage-gated cation channels and used for the treatment of hyperexcitability disorders.
Myonuclei acquired by overload exercise precede hypertrophy and are not lost on detraining
Authors: Bruusgaard J. C. , Johansen I. B. , Egner I. M. , Rana Z. A. , Gundersen K.
Published: August 2010

Effects of previous strength training can be long-lived, even after prolonged subsequent inactivity, and retraining is facilitated by a previous training episode. Traditionally, such “muscle memory” has been attributed to neural factors in the absence of any identified local memory mechanism in the muscle tissue. We have used in vivo imaging techniques to study live myonuclei belonging to distinct muscle fibers and observe that new myonuclei are added before any major increase in size during overload. The old and newly acquired nuclei are retained during severe atrophy caused by subsequent denervation lasting for a considerable period of the animal’s lifespan. The myonuclei seem to be protected from the high apoptotic activity found in inactive muscle tissue. A hypertrophy episode leading to a lasting elevated number of myonuclei retarded disuse atrophy, and the nuclei could serve as a cell biological substrate for such memory. Because the ability to create myonuclei is impaired in the elderly, individuals may benefit from strength training at an early age, and because anabolic steroids facilitate more myonuclei, nuclear permanency may also have implications for exclusion periods after a doping offense.
miR-204 is required for lens and retinal development via
Meis2
targeting
Authors: Conte Ivan , Carrella Sabrina , Avellino Raffaella , Karali Marianthi , Marco-Ferreres Raquel , Bovolenta Paola , Banfi Sandro
Published: August 2010

MicroRNAs (miRNAs) are small noncoding RNAs that have important roles in the regulation of gene expression. The roles of individual miRNAs in controlling vertebrate eye development remain, however, largely unexplored. Here, we show that a single miRNA, miR-204, regulates multiple aspects of eye development in the medaka fish (
Oryzias latipes
). Morpholino-mediated ablation of miR-204 expression resulted in an eye phenotype characterized by microphthalmia, abnormal lens formation, and altered dorsoventral (D-V) patterning of the retina, which is associated with optic fissure coloboma. Using a variety of in vivo and in vitro approaches, we identified the transcription factor
Meis2
as one of the main targets of miR-204 function. We show that, together with altered regulation of the Pax6 pathway, the abnormally elevated levels of
Meis2
resulting from miR-204 inactivation are largely responsible for the observed phenotype. These data provide an example of how a specific miRNA can regulate multiple events in eye formation; at the same time, they uncover an as yet unreported function of Meis2 in the specification of D-V patterning of the retina.