bluuebunny/crossref_metadata_2025 huggingface dataset:
LibSBGN: current status and future plans
Authors: Villeger Alice
Published: November 2010

LibSBGN is a community project started in 2009: it aims at facilitating the development of SBGN-compliant tools, and improving interoperability between these tools.These goals will be achieved by defining a standardized electronic implementation of the Systems Biology Graphical Notation: an XML-based file format (SBGN-ML), complemented by a software library (LibSBGN).The project is organized around a number of online tools, which allow the community to discuss problems, share ideas, and formalize solutions.Current versions of SBGN-ML and LibSBGN have already been adopted by three different SBGN-compliant tools. The first official release of SBGN-ML is imminent.For more information:http://libsbgn.sourceforge.net
Metagenomic study of the human skin microbiome associated with acne
Authors: Li Huiying
Published: November 2010

The human microbiota contributes to our normal postnatal development and plays a significant role in defining our physiology. To understand the role of microbiota in human health and disease, we study the skin microbiome in pilosebaceous units (hair follicles) and its association with acne.Acne is one of the most common skin diseases. Although its etiology still needs to be defined, a bacterial factor has been suggested in the development of the disease. In fact, antibiotic therapy targeting Propionibacterium acnes has been a mainstay treatment for more than 30 years.Our preliminary study shows that the microcomedone, a specialized skin compartment where acne arises, has a tractable microbiome, with a single dominant species, P. acnes. This system offers a unique advantage allowing in-depth analysis of a human microbiome at the subspecies level by sequencing. Our preliminary study suggests that the microbiome associated with acne offers promise for understanding the correlation between the composition of the microbiome and human health and disease.The goal of the project is to determine whether the microbiota in the pilosebaceous units contributes to acne. We plan to investigate the microbiome associated with acne in three directions. First, we plan to investigate the strain diversity of P. acnes in a disease cohort and a normal cohort and examine whether certain strains of P. acnes are correlated with the disease. Second, we plan to investigate the non- P. acnes microbes in microcomedones and disease lesions and examine whether they correlate with acne pathogenesis. Third, we will examine the interactions between the microbes and the host by transcriptional profiling of both the microbiota and the host.During the first year of this project, two main questions were asked. 1. Are certain strains of P. acnes associated with acne, but rarely found in normal individuals? 2. If specific strains are associated with acne, what are the differences in their genetic composition compared to other P. acnes strains that are not associated with acne? We collected microcomedone samples from more than 100 subjects, including acne patients and normal individuals. Genomic DNA was extracted from each sample, and 16S rDNA was amplified using universal primers (8F and 1510R), cloned and sequenced using Sanger method. Approximately 384 near full length 16S rDNA sequences were obtained for each sample. Some of the microcomedone samples were also cultured under anaerobic condition to isolate different P. acnes strains. Sixty-eight isolates were selected for whole genome shotgun sequencing using Solexa/Illumina platform. By the end of the first year of the project, we completed the sequencing of more than 40,000 16S rDNA clones and 68 genomes of P. acnes isolates.
Recovery kinetics of winter stressed conifers: The effects of growth light environment, extent of the season, and species.
Authors: Verhoeven Amy
Published: November 2010

Evergreens undergo a dramatic reduction in their maximal photochemical efficiency (measured as Fv/Fm) during winter, which is largely due to increases in a sustained form of thermal energy dissipation. Upon removing winter-stressed leaves to room temperature and low light, Fv/Fm recovers over several days and can include both a rapid phase (reversing in minutes) and a slow phase (reversing over days). Both phases are associated with reversal of sustained energy dissipation. Preliminary examination of recovery of evergreens monitored in January in Minnesota showed an absence of the rapid component to recovery. Our goal was to monitor recovery kinetics of sun and shade evergreens in Minnesota throughout winter in order to assess whether the rapid phase of recovery exists early in the winter and converts to the slowly reversible form as winter progresses. Four species of conifers (sun and shade needles) were monitored during the winter of 2007/08: eastern white pine (_Pinus strobus_ L.), balsam fir [Abies balsamea (L.) P. Mill], Taxus cuspidata (L.) and blue spruce (Picea pungens Engelm.). Fv/Fm was measured on dark acclimated needles in the field, twigs were collected, brought indoors and maintained at room temperature and low light where Fv/Fm was monitored for six days.The results demonstrated that all species, and both sun and shade needles, showed a rapidly reversible component to recovery in early winter (November). In the sun needles this component was rarely present later in the season, while in the shade needles it was present (although only a small fraction of the total sustained energy dissipation) on most days monitored during winter. The slowly reversible component to sustained energy dissipation was present in both sun and shade needles of all species beginning in November. In all cases, shade needles recovered significantly faster than sun needles. There was a significant slowing of recovery (the slowly reversible component) as winter progressed in both sun and shade needles, and significant differences between species in their recovery response. The results indicate a relatively small contribution of the rapidly reversible component of sustained energy dissipation compared with earlier studies on evergreens growing in the milder winter conditions of Colorado. The results also provide evidence that the rapid component to recovery diminishes as the season progresses, particularly in needles growing in full sun where the slowly reversible component of sustained energy dissipation accounts for most or all of the observed sustained energy dissipation.
Decapitated and decaudated spermatozoa in man, and pathogenesis based on the ultrastructure
Authors: Toyama Yoshiro , Iwamoto Teruaki , Yajima Michitaka , Baba Katsuyuki , Yuasa Shigeki
Published: November 2010

The ultrastructure of decapitated tails and decaudated heads of ejaculated spermatozoa from an infertile man were investigated. The decaudated heads had the nucleus and acrosome, but neither the implantation fossa nor the basal plate were observed at the caudal pole of the nucleus. The nuclear membrane at this portion showed numerous nuclear pores. The decapitated tails contained the proximal centriole at the proximal end. In addition, most decapitated tails had segmented columns, outer coarse fibres, axoneme, mitochondrial sheath and fibrous sheath in the normal position. The ultrastructure reflects the high motility of the decapitated tails of the spermatozoa. Drastic abnormalities were found in the developing spermatids in the biopsied testes. In spermatids later than the Golgi phase, the pair of centrioles were floating in the cytoplasm of the spermatid, but the distal centriole elongated the flagellum. Neither the implantation fossa nor the basal plate were observed at the caudal pole of the nucleus. It is concluded that the tail might be separated from the head before or after completion of tail formation in spermatids. The explanation for why the proximal centriole failed to connect to the nucleus is unknown.
Medical illustration: from caves to cyberspace‡
Authors: Tsafrir Jenni , Ohry Avi
Published: November 2010

The human body has been depicted in ancient cave‐paintings, in primitively sculpted figures, and through all the ages in various forms of artistic expression. The earliest medical texts were descriptive but not illustrated. Later, as it became clear that knowledge of the human body and all its systems was essential to the practice of healing, texts were accompanied by illustrations which became an integral part of the teaching process. The illustrators included artists, whose interest was primarily artistic, but who were sometimes employed by surgeons or physicians to illustrate their texts. Occasionally, the physicians or scientists accompanied their texts with their own illustrations, and in the last century, medical illustration, in its infinite variety of techniques, has been developed as a profession in its own right.

As knowledge was extended, permitted by social and cultural change, as well as by technological advances, the types of illustrations have ranged from gross anatomy through dissections showing the various organ systems, histological preparations, and radiological images, right up to the computerized digital imagery that is available today, which allows both static and dynamic two‐ and three‐dimensional representations to be transmitted electronically across the world in a matter of seconds.

The techniques used to represent medical knowledge pictorially have been as varied as the illustrators themselves, involving drawing, engraving, printing, photography, cinematography and digital processing. Each new technique has built on previous experience to broaden medical knowledge and make it accessible to an ever‐widening audience. This vast accumulation of pictorial material has posed considerable problems of storage, cataloguing, retrieval, display and dissemination of the information, as well as questions of ethics, validity, manipulation and reliability. This paper traces these developments, illustrating them with representative examples drawn from the inexhaustible store of documents accumulated over more than two millennia.
REALISE‐ing their potential?: implementing local library projects to support evidence‐based health care
Authors: Falzon Louise , Booth Andrew
Published: November 2010

Librarian involvement in Evidence‐based Health Care provides many opportunities at a local level. Unfortunately, the potential for innovative projects to inform future developments is generally lost by a failure to ‘pass the baton’—to identify lessons learnt and transferable principles. The ‘Library Support for Evidence‐based Health Care’ Project, funded by the NHS Executive Northern and Yorkshire, resulted in the implementation of locally responsive packages of hardware and software in six of the Region’s libraries. The opportunity to evaluate the collective experience of these sites, and to synthesize principles of good practice, was provided by a separately funded post‐hoc evaluation, the Research Evaluation to Audit Library and Information Support for EBHC (REALISE). This paper reports on how this evaluation was conducted, documents the strengths and weaknesses of the Project itself, and attempts to provide a checklist for use in similar projects. The paper concludes by outlining the relevance of the findings to the introduction of planned organizational approaches to quality (clinical governance) and the development of local implementation strategies across the UK, required by the NHS Information Strategy, Information for Health.
Barrier creams – skin protectants: can you protect skin?
Authors: Zhai H , Maibach H I
Published: November 2010

Barrier creams (BC) are used in hand care to protect the user against damage from surfactants and other irritants; their clinical value remains debatable; some reports indicate that inappropriate BC application might induce a deleterious rather than a beneficial effect. Since many cosmetic formulations contain ‘skin protectants’, we review concept, application, and efficacy from the pertinent scientific literature.
Electric field and force modeling for electrostatic levitation of lossy dielectric plates
Authors: Woo S. J. , Higuchi T.
Published: November 2010

Electrostatic levitation holds great promise for the semiconductor, solar panel, and flat-panel display industry where the handling of dielectrics in a contact-free manner can bring many advantages and solve long-standing contamination and particulate control problems. In this work an analytical model is developed for the electrostatic levitation field between a lossy dielectric plate and a generic stator electrode structure consisting of a regular planar array of parallel bar electrodes. Time-varying voltages of differing polarities are alternatingly applied to the bar electrodes. Atmospheric humidity-related surface conduction on the plate is explicitly taken into account in the model since it has a profound effect on the field dynamics. Based on this model, the electrostatic levitation force is calculated using the Maxwell stress tensor formulation. The levitation force dynamics are investigated by evaluating the transient response of the field under a step in the applied voltages. In this context, the rate of electric charge build up on the plate is characterized by the suspension initiation time (TSI), which is defined as the time elapsed between applying step voltages to the stator electrodes and start of lift-off of the dielectric plate from its initial position. TSI is theoretically predicted for 0.7 mm thick soda-lime glass substrates, typically used in the manufacturing of liquid crystal displays (LCDs), as a function of electrode geometry, air gap separation, ambient humidity, and step voltage magnitudes. The predicted results are shown to be in good agreement with previously published experimental data for soda-lime glass substrates.
A synthetic diagnostic for validation of electron gyroradius scale turbulence simulations against coherent scattering measurements
Authors: Poli F. M. , Ethier S. , Wang W. , Hahm T. S. , Mazzucato E. , Smith D. R.
Published: November 2010

Comparison between spectra of short-scale density fluctuations measured with coherent electromagnetic scattering experiments and those extracted from space-resolved numerical simulations is affected by a number of systematic errors. These include the locality of scattering measurements, the different domain covered (space-resolved simulations versus wavenumber resolved measurements), and the stationarity of simulated nonlinear spectra. To bridge the gap between theory-simulations and experiments, a synthetic diagnostic for high-k scattering measurements has been developed. This synthetic scattering predicts the propagation of the beam in an anisotropic, inhomogeneous plasma and accounts for the spatial variation of the instrumental transfer function. The latter, in particular, is proven to provide an important calibration factor not only for the simulated spectra, but also for the measured ones, allowing the use of the synthetic diagnostic in predictive mode. Results from a case study for National Spherical Torus Experiment plasmas using high-k tangential scattering system [Smith et al., Rev. Sci. Instrum. 75, 3840 (2004)] and the gyrokinetic tokamak simulation code [Wang et al., Phys. Plasmas 13, 092505 (2006)] are presented.
A simple proof of Birkhoff's theorem for cosmological constant
Authors: Schleich Kristin , Witt Donald M.
Published: November 2010

We provide a simple, unified proof of Birkhoff’s theorem for the vacuum and cosmological constant case, emphasizing its local nature. We discuss its implications for the maximal analytic extensions of Schwarzschild, Schwarzschild(–anti)-de Sitter, and Nariai spacetimes. In particular, we note that the maximal analytic extensions of extremal and overextremal Schwarzschild–de Sitter spacetimes exhibit no static region. Hence the common belief that Birkhoff’s theorem implies staticity is false for the case of positive cosmological constant. Instead, the correct point of view is that generalized Birkhoff’s theorems are local uniqueness theorems whose corollary is that locally spherically symmetric solutions of Einstein’s equations exhibit an additional local Killing vector field.
Skin effect with arbitrary specularity in Maxwellian plasma
Authors: Latyshev A. V. , Yushkanov A. A.
Published: November 2010

The problem of the skin effect with arbitrary specularity in Maxwellian plasma with specular–diffuse boundary conditions is solved. A new analytical method is developed that makes it possible to obtain a solution up to an arbitrary degree of accuracy. The method is based on the idea of symmetric continuation of not only the electric field, but also electron distribution function. The solution is obtained in a form of von Neumann series.
Experimental measurement of the van der Waals binding energy of X–O2 clusters (X=Xe,CH3I,C3H6,C6H12)
Authors: Vidma Konstantin V. , Bogdanchikov Georgii A. , Baklanov Alexey V. , Chestakov Dmitri A. , Parker David H.
Published: November 2010

Van der Waals binding energies for the X–O2 complexes (X=Xe,CH3I,C3H6,C6H12) are determined by analysis of experimental velocity map imaging data for O(P32) atoms arising from UV-photodissociation of the complex [A. V. Baklanov et al., J. Chem. Phys. 126, 124316 (2007)]. Several dissociation pathways have been observed, we focus on the channel corresponding to prompt dissociation of X–O2 into X+2O(P3) fragments, which is present for complexes of O2 with all partners X. Our method is based on analysis of the kinetic energy of all three photofragments, where the O atom kinetic energy was directly measured in the experiment and the kinetic energy of the X partner was calculated using momentum conservation, along with the measured angular anisotropy for O atom recoil. We exploit the fact that the clusters are all T-shaped or nearly T-shaped, which we also confirm by ab initio calculations, along with knowledge of the transition dipole governing radiative absorption by the complex. The effect of partitioning the kinetic energy between translation along the X–O2 and OO coordinates on the angular anisotropy of the O atom recoil direction is discussed. Van der Waals binding energies of 110±20 cm−1, 280±20 cm−1, 135±30 cm−1, and 585±20 cm−1 are determined for XeO2, CH3IO2, C3H6O2, and C6H12O2 clusters, respectively.
Transition from Mn4+ to Mn3+ induced by surface reconstruction at λ-MnO2(001)
Authors: Ouyang C. Y. , Šljivančanin Ž. , Baldereschi A.
Published: November 2010

Structural and electronic properties of the λ-MnO2(001) surface are investigated applying density functional theory approach. The calculations show that all Mn ions at unreconstructed smooth surface preserve the +4 oxidation state observed in the bulk. Upon the λ-MnO2(001) reconstruction, one fourth of Mn ions at the surface undergo a change of the oxidation state from +4 to +3, although the reconstruction does not change the Mn coordination number with oxygen. This is accompanied with the filling of initially empty 3\documentclass[12pt]{minimal}\begin{document}$d_{z^2}$\end{document}dz2 states localized on cations with one electron denoted by two neighboring O atoms. Although the reconstruction leads to an energy gain of 0.04 eV per surface unit cell, it is not a spontaneous process since it proceeds with an activation energy of 0.12 eV.
Quantification of antagonistic optomechanical forces in an interferometric detection system for dynamic force microscopy
Authors: Tröger L. , Reichling M.
Published: November 2010

In fiber-optic interferometer systems detecting oscillatory cantilever motion, the intensity distribution of the light field in the interferometric cavity generates an optomechanical coupling determining the effective properties of the oscillating system. For a low finesse cavity established by an uncoated cantilever and the fiber end, the resonance frequency and spring constant are shifted mainly due to radiation pressure whereas the Q-factor is varied due to photothermal forces under typical conditions. We find, that radiation pressure and photothermal force act in opposite directions and discuss the retardation times governing the antagonistic effects differing by orders of magnitude.
Transient convective instabilities in directional solidification
Authors: Meca E. , Ramírez-Piscina L.
Published: November 2010

We study the convective instability of the melt during the initial transient in a directional solidification experiment in a vertical configuration. We obtain analytically the dispersion relation and perform an additional asymptotic expansion for large solutal Rayleigh number that permits a simpler analytical analysis and a better numerical behavior. We find a transient instability, i.e., a regime, in which the system destabilizes during the transient whereas the final unperturbed steady state is stable. This could be relevant to growth mode predictions in solidification.
Effects of Te nanowire microstructure and Bi3+ reduction rate on Bi2Te3 nanotubes
Authors: Kim Sook Hyun , Park Byung Ki
Published: November 2010

To synthesize Bi2Te3 nanotubes with a one-dimensional structure, Te nanowires were prepared as templates via a solvothermal method. Subsequently, on the basis of atomic diffusion, Te was alloyed with Bi obtained by liquid-phase reduction in Bi3+. A hollow structure was formed as a result of a difference in the diffusion rates between the two atoms. Microstructural features of Te nanowires such as a particle morphology, crystal density, and aspect ratio, were determined by the synthetic temperature, and had a great influence on the alloying between Bi and Te into Bi2Te3 nanotubes. In addition, alloying was affected by the diffusion rate of Te atoms and the concentration of the agent for reducing Bi3+ to Bi.
Silicon waveguides and ring resonators at 5.5 μm
Authors: Spott Alexander , Liu Yang , Baehr-Jones Tom , Ilic Rob , Hochberg Michael
Published: November 2010

We demonstrate low loss ridge waveguides and the first ring resonators for the mid-infrared, for wavelengths ranging from 5.4 to 5.6 μm. Structures were fabricated using electron-beam lithography on the silicon-on-sapphire material system. Waveguide losses of 4.0±0.7 dB/cm are achieved, as well as Q-values of 3.0 k.
Resonance photoemission studies of (111) oriented CeO2 thin film grown on Si (100) substrate by pulsed laser deposition
Authors: Khare Amit , Choudhary R. J. , Bapna Komal , Phase D. M. , Sanyal Sankar P.
Published: November 2010

The electronic structure of CeO2 thin film grown by pulsed laser deposition on Si (100) substrate has been investigated using resonance photoemission spectroscopy (RPES). X-ray photoemission study on the film suggests that Ce has 3+ and 4+ valence states. Valence band spectra of the film show a feature at 2.1 eV of binding energy and a broad band at higher binding energy due to O 2p derived state. RPES measurements performed in the Ce 4d→4f photoabsorption region show maximum intensity for 2.1 eV feature at photon energy of 122 eV confirming it to be due to Ce3+ (4f1) state. RPES measurements also show maximum intensity for binding energy position of 4.4 eV in the broad band at photon energy of 125 eV, suggesting it to be due to Ce4+ (4f0) state. Constant initial state (CIS) versus photon energy plots also confirm these findings and suggest that the broad band is admixture of O 2p and Ce 4f and 5d derived states.
Microfluidic on-chip fluorescence-activated interface control system
Authors: Haiwang Li , Nguyen N. T. , Wong T. N. , Ng S. L.
Published: November 2010

A microfluidic dynamic fluorescence-activated interface control system was developed for lab-on-a-chip applications. The system consists of a straight rectangular microchannel, a fluorescence excitation source, a detection sensor, a signal conversion circuit, and a high-voltage feedback system. Aqueous NaCl as conducting fluid and aqueous glycerol as nonconducting fluid were introduced to flow side by side into the straight rectangular microchannel. Fluorescent dye was added to the aqueous NaCl to work as a signal representing the interface position. Automatic control of the liquid interface was achieved by controlling the electroosmotic effect that exists only in the conducting fluid using a high-voltage feedback system. A LABVIEW program was developed to control the output of high-voltage power supply according the actual interface position, and then the interface position is modified as the output of high-voltage power supply. At last, the interface can be moved to the desired position automatically using this feedback system. The results show that the system presented in this paper can control an arbitrary interface location in real time. The effects of viscosity ratio, flow rates, and polarity of electric field were discussed. This technique can be extended to switch the sample flow and droplets automatically.
On the Boltzmann relation in a cold magnetized plasma
Authors: Nasi L. , Raimbault J.-L.
Published: November 2010

A systematic and exact comparison between the forces acting on magnetized electrons in a current-free plasma is considered within a fluid model. We show that the Boltzmann relation is fulfilled in the drift-diffusion approximation when (hi/he)(1+he2)/(1+hi2)⪡1 where he (or hi) is the ratio of the electron (or ion) cyclotron to the collision frequency. When the nonlinear inertia terms are taken into account, the previous criterion is too rough and must be modified. In particular it is proved that the Boltzmann relation is not uniformly valid in the plasma. The case of bounded plasmas where the electron temperature must be determined self-consistently is discussed in detail.
Direct laser writing of whispering gallery microcavities by two-photon polymerization
Authors: Liu Zhao-Pei , Li Yan , Xiao Yun-Feng , Li Bei-Bei , Jiang Xue-Feng , Qin Yi , Feng Xiao-Bo , Yang Hong , Gong Qihuang
Published: November 2010

We demonstrate that high-Q polymer whispering gallery microcavities can be directly written by the two-photon polymerization of zirconium/silicon hybrid sol-gel, benefiting from the high spatial resolution and three-dimensional nature of this direct laser writing technique. The quality factors of the fabricated whispering gallery microcavities are up to 1.48×105 limited by the material absorption. The surface roughness is less than 12 nm. This opens the way to fabricate intricate three-dimensional microcavities for the fundamental and applied physics research based on optical resonators.
A low-noise, single-photon avalanche diode in standard 0.13 μm complementary metal-oxide-semiconductor process
Authors: Field Ryan M. , Lary Jenifer , Cohn John , Paninski Liam , Shepard Kenneth L.
Published: November 2010

We present the design and characterization of a single-photon avalanche diode (SPAD) fabricated with a standard 0.13 μm complementary metal-oxide-semiconductor process. We have developed a figure of merit for SPADs when these detectors are employed in high frame-rate fluorescent lifetime imaging microscopy, which allows us to specify an optimal bias point for the diode and compare our diode with other published devices. At its optimum bias point at room temperature, our SPAD achieves a photon detection probability of 29% while exhibiting a dark count rate of only 231 Hz and an impulse response of 198 ps.
Dynamical Franz–Keldysh effect in GaAs/AlGaAs multiple quantum wells induced by single-cycle terahertz pulses
Authors: Shinokita K. , Hirori H. , Nagai M. , Satoh N. , Kadoya Y. , Tanaka K.
Published: November 2010

We studied absorption spectra near the band gap of GaAs/AlGaAs multiple quantum wells subjected to strong single-cycle terahertz pulses. With an increasing terahertz electric field, the heavy-hole 1s exciton energy near the band gap redshifts, reaches a maximum, and turns to blueshift. The blueshift increases proportionally to the ponderomotive energy, i.e., the terahertz electric field squared, which differs from the response expected from the Frantz–Keldysh effect (FKE) in a dc electric field. This fact suggests that the observed ponderomotive energy dependence of the blueshift can be ascribed to the dynamical FKE.
Enhanced ferroelectric and piezoelectric properties in doped lead-free (Bi0.5Na0.5)0.94Ba0.06TiO3 thin films
Authors: Wang D. Y. , Chan N. Y. , Li S. , Choy S. H. , Tian H. Y. , Chan H. L. W
Published: November 2010

Doping effects with respect to the electrical properties of morphotropic phase boundary (Bi0.5Na0.5)0.94Ba0.06TiO3 thin films epitaxially grown on CaRuO3 electroded (LaAlO3)0.3(Sr2AlTaO6)0.35 (001) substrates were investigated. Substantial enhancement of ferroelectricity and piezoelectricity has been achieved in La+Ce codoped films with a remanent polarization Pr of 29.5 μC/cm2 and a remanent piezoelectric coefficient d33,f of 31 pm/V, whereas Mn doping seems more favorite to reduce the leakage current by two order of magnitude. Both doped films exhibited diodelike I-V characteristics, which are correlated with resistance switching effect.
Molecular diffusivity measurement through an alumina membrane using time-resolved fluorescence imaging
Authors: Kennard Raymond , DeSisto William J. , Mason Michael D.
Published: November 2010

We present a simple fluorescence imaging method for measuring the time-resolved concentration of a fluorescent molecule diffusing through an anodic alumina membrane with a pore diameter of 20 nm. From the concentration breakthrough curve, the molecular diffusivity of the fluorophore was extracted. The experimentally determined diffusivity was three orders of magnitude lower than reported bulk values. Due to the relative simplicity and ease of use, this method can be applied to provide fundamental information for biomolecular separations applications. One feature of this method is the high sensitivity at intercellular volumes broadening its application to drug delivery and controlled cell growth.
Design considerations and propagation characteristics of channel Bragg-plasmon-coupled-waveguides
Authors: Srivastava Triranjita , Das Ritwick , Jha Rajan
Published: November 2010

We present a detailed design principle and propagation characteristics of channel Bragg-plasmon-coupled-waveguide. We have found that there is a significant change in the slope of the phase-velocity dispersion curve leading to an ultranarrow interaction bandwidth (∼765 pm) and group-velocity dispersion (GVD∼±4.5×104 ps/km-nm) that is an appreciably large GVD using a waveguide mode-coupling geometry in any region of the optical spectrum. The effect of waveguide parameters such as channel width, number of bilayers, etc. on a mode-coupling mechanism is also studied with significant emphasis on the propagation loss suffered by the supermodes of the structure. The proposed waveguide exhibits sensitivity as high as 7500 nm/RIU, thereby opening a route for biochemical sensing.
Direct growth of InAsP/InP quantum well heterostructures on Si using crystalline SrTiO3/Si templates
Authors: Gobaut B. , Penuelas J. , Cheng J. , Chettaoui A. , Largeau L. , Hollinger G. , Saint-Girons G.
Published: November 2010

Integrating III-V semiconductors on Si is one of the major challenges of epitaxial growth and presents important applicative interest. We describe here an approach based on the use of crystalline SrTiO3 (STO)/Si templates. The structural and optical properties of InAsP/InP quantum well heterostructures grown directly on Si and on STO/Si templates are compared. Using STO/Si templates strongly improves the structural properties of the III-V heterostructure, and allows observing room-temperature photoluminescence from the quantum well.
Reversal of orbital magnetic moment on substitution of Bi in multiferroic Co2MnO4: A magnetic Compton scattering study
Authors: Ahuja B. L. , Dashora Alpa , Heda N. L. , Tiwari Shailja , Rajeevan N. E. , Itou M. , Sakurai Y. , Kumar Ravi
Published: November 2010

Temperature and field dependent magnetic Compton profiles of BixCo2−xMnO4 (x=0 and 0.3) multiferroics are reported. The magnetic Compton profiles and total spin moments are interpreted in terms of Mn/Co-3d contribution. Mn spin moments are found to be dominating in total magnetization whereas a small contribution of Co spin moment couples antiferromagnetically with that from Mn sites. The magnetic Compton data when compared with magnetization data, interestingly, show a reverse trend of orbital magnetic moments which are explained in terms of exchange interaction between the ions at different sites via O2− ions.
Flexible Sm–Fe/polyvinylidene fluoride heterostructural film with large magnetoelectric voltage output
Authors: Zhao Shifeng , Wan Jian-guo , Yao Mengliang , Liu Jun-ming , Song Fengqi , Wang Guanghou
Published: November 2010

The Sm–Fe/polyvinylidene fluoride (PVDF) heterostructural film was prepared by depositing Sm–Fe nanoclusters onto the flexible PVDF film using cluster beam deposition method. The PVDF film acts as both piezoelectric layer and substrate. The heterostructural film showed the well-defined microstructures in which the Sm–Fe layer was assembled by the nanoparticles, and the interface between Sm–Fe and PVDF layers was clear. The heterostructural film possessed evident magnetic anisotropy with in-plane easy axis and exhibited large voltage output under the magnetic bias. Such flexible heterostructural film with large magnetoelectric output makes it promising to be widely used for the weak magnetic-field detection.
Lensfree color imaging on a nanostructured chip using compressive decoding
Authors: Khademhosseinieh Bahar , Biener Gabriel , Sencan Ikbal , Ozcan Aydogan
Published: November 2010

We demonstrate subpixel level color imaging capability on a lensfree incoherent on-chip microscopy platform. By using a nanostructured substrate, the incoherent emission from the object plane is modulated to create a unique far-field diffraction pattern corresponding to each point at the object plane. These lensfree diffraction patterns are then sampled in the far-field using a color sensor-array, where the pixels have three different types of color filters at red, green, and blue (RGB) wavelengths. The recorded RGB diffraction patterns (for each point on the structured substrate) form a basis that can be used to rapidly reconstruct any arbitrary multicolor incoherent object distribution at subpixel resolution, using a compressive sampling algorithm. This lensfree computational imaging platform could be quite useful to create a compact fluorescent on-chip microscope that has color imaging capability.
Numerical simulation of supercritical trapped internal waves over topography
Authors: Soontiens Nancy , Subich Christopher , Stastna Marek
Published: November 2010

We consider the steady flow of a stratified fluid over topography in a fluid of finite vertical extent, as typified by experimental flumes with a rigid lid or the ocean under the rigid lid approximation. We do not specify a functional form of the upstream stratification or background current and derive a general version of the Dubreil–Jacotin–Long equation appropriate for the problem. This elliptic equation is strongly nonlinear and we develop an efficient, pseudospectral, iterative method for its numerical solution. The method allows us to compute laminar, trapped waves with amplitudes more than 50% of the depth of the fluid. We find that when either a background shear current is present or the topography is narrow enough, multiple steady states are possible and we confirm this finding by using integrations of the full time-dependent Euler equations. We discuss instances of waves with closed streamlines, finding that the presence of shear allows for waves with vortex cores that persist for long times in time-dependent simulations and match well with solutions of the steady theory. In contrast, streamline overturning in the absence of upstream shear only occurs for flows that are stratified near the surface and in this instance, time-dependent simulations yield unsteady cores that do not match steady results very well.
Quasistationary wake plasma wave excited by a comoving charged pulse
Authors: Wang Youmei , Yu M. Y.
Published: November 2010

Fully nonlinear quasistationary wake plasma waves excited by and comoving with a charged pulses are investigated. The characteristics of the excited plasma wave depend on a (nonlinear) resonance between the wave and the pulse. With two comoving driver pulses, localized wake structures without the long wakes can be produced.
Analytical evaluation of the Tsytovich–Angelis dust-dust collision functions arising from the kinetic theory of dusty plasmas
Authors: Mamedov B. A.
Published: November 2010

An efficient analytical calculation approach is presented for the Tsytovich–Angelis dust-dust collision functions consisting of the kinetic theory of dusty plasmas. This method is based on the use of binomial expansion theorem for the analytical representation of the dust-dust collision functions. The analytical calculation offers the advantage that leads to a mathematical expression, which allows the direct calculation of the dust-dust collision functions. The proposed algorithm is implemented numerically using a computer program, and its convergence properties are investigated.
Checkpoint genes and Exo1 regulate nearby inverted repeat fusions that form dicentric chromosomes in
Saccharomyces cerevisiae
Authors: Kaochar Salma , Shanks Lisa , Weinert Ted
Published: November 2010

Genomic rearrangements are common, occur by largely unknown mechanisms, and can lead to human diseases. We previously demonstrated that some genome rearrangements occur in budding yeast through the fusion of two DNA sequences that contain limited sequence homology, lie in inverted orientation, and are within 5 kb of one another. This inverted repeat fusion reaction forms dicentric chromosomes, which are well-known intermediates to additional rearrangements. We have previously provided evidence indicating that an error of stalled or disrupted DNA replication forks can cause inverted repeat fusion. Here we analyze how checkpoint protein regulatory pathways known to stabilize stalled forks affect this form of instability. We find that two checkpoint pathways suppress inverted repeat fusion, and that their activities are distinguishable by their interactions with exonuclease 1 (Exo1). The checkpoint kinase Rad53 (Chk2) and recombination protein complex MRX(MRN) inhibit Exo1 in one pathway, whereas in a second pathway the ATR-like kinases Mec1 and Tel1, adaptor protein Rad9, and effector kinases Chk1 and Dun1 act independently of Exo1 to prevent inverted repeat fusion. We provide a model that indicates how in Rad53 or MRX mutants, an inappropriately active Exo1 may facilitate faulty template switching between nearby inverted repeats to form dicentric chromosomes. We further investigate the role of Rad53, using hypomorphic alleles of Rad53 and null mutations in Rad9 and Mrc1, and provide evidence that only local, as opposed to global, activity of Rad53 is sufficient to prevent inverted repeat fusion.
Specific erythroid-lineage defect in mice conditionally deficient for Mediator subunit Med1
Authors: Stumpf Melanie , Yue Xiaojing , Schmitz Sandra , Luche Hervé , Reddy Janardan K. , Borggrefe Tilman
Published: November 2010

The Mediator complex forms the bridge between transcriptional activators and the RNA polymerase II. Med1 (also known as PBP or TRAP220) is a key component of Mediator that interacts with nuclear hormone receptors and GATA transcription factors. Here, we show dynamic recruitment of GATA-1, TFIIB, Mediator, and RNA polymerase II to the β-globin locus in induced mouse erythoid leukemia cells and in an erythropoietin-inducible hematopoietic progenitor cell line. Using Med1 conditional knockout mice, we demonstrate a specific block in erythroid development but not in myeloid or lymphoid development, highlighted by the complete absence of β-globin gene expression. Thus, Mediator subunit Med1 plays a pivotal role in erythroid development and in β-globin gene activation.
Caveolin-1 knockout mice exhibit impaired induction of mGluR-dependent long-term depression at CA3-CA1 synapses
Authors: Takayasu Yukihiro , Takeuchi Koichi , Kumari Ranju , Bennett Michael V. L. , Zukin R. Suzanne , Francesconi Anna
Published: November 2010

Group I metabotropic glutamate receptors (mGluR1/5) are important to synaptic circuitry formation during development and to forms of activity-dependent synaptic plasticity. Dysregulation of mGluR1/5 signaling is implicated in some disorders of neurodevelopment, including fragile X syndrome, the most common inherited form of intellectual disabilities and leading cause of autism. Site(s) in the intracellular loops of mGluR1/5 directly bind caveolin-1, an adaptor protein that associates with membrane rafts. Caveolin-1 is the main coat component of caveolae and organizes macromolecular signaling complexes with effector proteins and membrane receptors. We report that long-term depression (LTD) elicited by a single application of the group I mGluR selective agonist (
RS
)-3,5-dihydroxyphenylglycine (DHPG) was markedly attenuated at Schaffer collateral-CA1 synapses of mice lacking caveolin-1 (

Cav1
−/−

), as assessed by field recording. In contrast, multiple applications of DHPG produced LTD comparable to that in WT mice. Passive membrane properties, basal glutamatergic transmission and NMDA receptor (NMDAR)-dependent LTD were unaltered. The remaining LTD was reduced by anisomycin, an inhibitor of protein synthesis, by U0126, an inhibitor of MEK1/2 kinases, and by rapamycin, an inhibitor of mammalian target of rapamycin (mTOR), suggesting mediation by the same mechanisms as in WT. mGluR1/5-dependent activation (phosphorylation) of MEK and extracellular signal-regulated kinase (ERK1/2) was altered in

Cav1
−/−

mice; basal phosphorylation was increased, but a single application of DHPG had no further effect, and after DHPG, phosphorylation was similar in WT and

Cav1
−/−

mice. Taken together, our findings suggest that caveolin-1 is required for normal coupling of mGluR1/5 to downstream signaling cascades and induction of mGluR-LTD.
Improved probability of detection of ecological “surprises”
Authors: Lindenmayer D. B. , Likens G. E. , Krebs C. J. , Hobbs R. J.
Published: November 2010

Ecological “surprises” are defined as unexpected findings about the natural environment. They are critically important in ecology because they are catalysts for questioning and reformulating views of the natural world, help shape assessments of the veracity of a priori predictions about ecological trends and phenomena, and underpin questioning of effectiveness of resource management. Despite the importance of ecological surprises, major gaps in understanding remain about how studies might be done differently or done better to improve the ability to identify them. We outline the kinds of ecological surprises that have arisen from long-term research programs that we lead in markedly different ecosystems around the world. Based on these case studies, we identify important lessons to guide both existing studies and new investigations to detect ecological surprises more readily, better anticipate unusual ecological phenomena, and take proactive steps to plan for and alleviate “undesirable” ecological surprises. Some of these lessons include: (
i
) maintain existing, and instigate new, long-term studies; (
ii
) conduct a range of kinds of parallel and concurrent research in a given target area; (
iii
) better use past literature and conceptual models of the target ecosystem in posing good questions and developing hypotheses and alternative hypotheses; and (
iv
) increase the capacity for ecological research to take advantage of opportunities arising from major natural disturbances. We argue that the increased anticipatory capability resulting from these lessons is critical given that ecological surprises may become more prevalent because of climate change and multiple and interacting environmental stressors.
Postsynaptic GluA1 enables acute retrograde enhancement of presynaptic function to coordinate adaptation to synaptic inactivity
Authors: Lindskog Maria , Li Li , Groth Rachel D. , Poburko Damon , Thiagarajan Tara C. , Han Xue , Tsien Richard W.
Published: November 2010

Prolonged blockade of AMPA-type glutamate receptors in hippocampal neuron cultures leads to homeostatic enhancements of pre- and postsynaptic function that appear correlated at individual synapses, suggesting some form of transsynaptic coordination. The respective modifications are important for overall synaptic strength but their interrelationship, dynamics, and molecular underpinnings are unclear. Here we demonstrate that adaptation begins postsynaptically but is ultimately communicated to presynaptic terminals and expressed as an accelerated turnover of synaptic vesicles. Critical postsynaptic modifications occur over hours, but enable retrograde communication within minutes once AMPA receptor (AMPAR) blockade is removed, causing elevation of both spontaneous and evoked vesicle fusion. The retrograde signaling does not require spiking activity and can be interrupted by NBQX, philanthotoxin, postsynaptic BAPTA, or external sequestration of BDNF, consistent with the acute release of retrograde messenger, triggered by postsynaptic Ca
2+
elevation via Ca
2+
-permeable AMPARs.
Language and Nation
Authors: Görlach Manfred
Published: November 2010

The concept of linguistic nationalism is first recorded for England in the 16th century, when the dominance of English had to be re-established in fields like the law, science and administration. In the centuries that followed, statements underlining the link between national language and nation are few — even on the Celtic fringe. It was the American Revolution which gave birth to a new centre of anglophones proud of their independent standards; a similar development but with increasingly weaker results has affected Australia, New Zealand, Canada and South Africa. Second-language countries like India are trailing even further behind, not to mention the problems of creole communities like those in the Caribbean, West Africa or the Southwest Pacific. My paper looks at these communities for evidence of a correlation between linguistic and political independence, standardization and prestige associated with use of the vernacular, and discusses problems connected with the development of alternatives like the standardization of an indigenous language to serve as a badge of national prestige, and as an expression of democratic intentions.
The English Language in Mauritius
Authors: Stein Peter
Published: November 2010

Mauritius was a British colony for almost 200 years, but except in the domains of administration and teaching, the English language was never really spoken on the island. This article traces its local history and its failure to establish itself as a replacement for French (and perhaps also the French-based creole) during the 19th and the first half of the 20th century. English is still the official language of Mauritius, but a large proportion of the population does not speak it at all or has at best a very limited knowledge of it. Nonetheless, no other language spoken on the island presents itself as a viable alternative. The historical overview and the discussion of the present situation are complemented by an analysis of the language tables taken from the population censuses of 1931 to 1990 and some data from an inquiry made by the author in the mid-seventies. To complete the study, the English influence on French and Creole is shown, and three specimens of Mauritian English as spoken by young people are given and commented on.
The Origins of New Zealand Speech
Authors: Gordon Elizabeth
Published: November 2010

New Zealand English has evolved in the past 150 years, at a time when it is possible to find both written and spoken evidence of its development. This paper takes evidence gained from an analysis of written comments on early New Zealand English and compares this with data taken from an
analysis of spoken New Zealand English obtained from recordings collected in the 1940s of old New Zealanders born in the 1850s-1890s — the period when the New Zealand accent was developing. By putting the written data beside the spoken data it is now possible to assess the accuracy of written records as a basis for the reconstruction of the earliest form of New Zealand English.