bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural effects of dopants and polymerization methodologies on the solid‐state ordering and morphology of polyaniline
Authors: Jayakannan M. , Annu S. , Ramalekshmi S.
Published: April 2005

The solid‐state three‐dimensional ordering of polyaniline–dopant complexes was investigated with four structurally different sulfonic acid dopants. The doped materials were produced in three different ways: polyaniline emeraldine base doped with sulfonic acid (aqueous route), in situ polymerization at the organic–water solvent interface (interfacial route), and in situ polymerization in organic and aqueous solvent mixtures (bilayer route). p‐Toluenesulfonic acid (PTSA), 5‐sulfosalicilic acid (SSA), camphorsulfonic acid (CSA), and dodecylbenzene sulfonic acid (DBSA) were employed as dopants. The conductivity of the aqueous‐route samples showed 10 and 100 times higher conductivity than the interfacial and bilayer routes, respectively. WXRD studies suggested that the crystallinity of the doped samples was dependent on both the structure of the dopants and the polymerization techniques. DBSA increases the polyaniline interplanar distance and produced highly crystalline materials via the aqueous and bilayer routes but failed with the interfacial route because of poor solubility in water. CSA, PTSA, and SSA produced highly crystalline samples by the interfacial route but failed with the aqueous (except for CSA) and bilayer routes. SEM analysis revealed that the doped materials of the interfacial route had excellent continuous morphology and uniform submicrometer‐size particle distributions in comparison with those of the aqueous and bilayer routes. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1321–1331, 2005
Application of microvascular free flaps to burn deformities
Authors: Ohmori Kitaro
Published: April 2005

Recent progress in the field of microvascular surgery has opened the way for various types of free tissue transplantation. Surgery involving the revascularization of free tissues by microvascular anastomoses of their arteriovenous pedicle to recipient artery and vein has come to be known by the generic term “free flap surgery”. This operative procedure makes it possible to achieve one‐stage treatment of tissue defects. To date, this useful surgical procedure, has been applied to the correction of extensive burn deformities in 44 patients with good results. This paper describes the operative procedure and a few representative cases of free flap transfer. It is our conviction that free flap surgery has a bright future.
Seasonal cycles and persistence in an acarine predator‐prey system on cassava in Africa
Authors: Hanna Rachid , Onzo Alexis , Lingeman Robert , Yaninek J. Steve , Sabelis Maurice W.
Published: April 2005

We applied time series analysis and a mechanistic predator‐prey model to long‐term data of monthly population counts of the herbivorous pest miteMononychellus tanajoaand its introduced phytoseiid predatorTyphlodromalus aripofrom a cassava field in Benin, West Africa. In this approach, we determined the extent to which the main features of the observed predator‐prey fluctuations in cassava fields can be explained from biotic traits inherent to the biology of predator and prey, and the extent of the significance of abiotic factors in determining population levels. The time series analyses with cross‐correlation showed that the period of predator‐prey fluctuations coincided with the annual pattern of intense rainfall and onset of dry season. A pronouncedM. tanajoapeak followed after a short lag (2 weeks) by aT. aripopeak coincided with a trough in rainfall intensity. Both the prey and predator had local and lower peaks that coincided with high rainfall intensity, but with a considerably longer lag (ca. 3 months) compared with the high peaks occurring at the onset of the dry season. Regression of log‐transformed data series (over a 7‐year period) showed that—except for the first year after predator release—M. tanajoafluctuated around an almost time‐invariant mean population density, whileT. aripodensities showed a consistent decline over the full observation period. To explain observed trends and periodic components in the data‐series of predator and prey densities, we review hypotheses that are based on (1) the annual patterns and trends in abiotic factors, (2) mechanisms endogenous to the predator‐prey system and (3) a combination of exogenous and endogenous factors.
On the three-dimensional Euler equations with a free boundary subject to surface tension
Authors: Schweizer Ben
Published: April 2005

We study an incompressible ideal fluid with a free surface that is subject to surface tension; it is not assumed that the fluid is irrotational. We derive a priori estimates for smooth solutions and prove a short-time existence result. The bounds are obtained by combining estimates of energy type with estimates of vorticity type and rely on a careful study of the regularity properties of the pressure function. An adequate artificial coordinate system is used instead of the standard Lagrangian coordinates. Under an assumption on the vorticity, a solution to the Euler equations is obtained as a vanishing viscosity limit of solutions to appropriate Navier–Stokes systems.
The impact of depression is unevenly distributed in the population
Authors: Isacson Dag , Bingefors Kerstin , von Knorring Lars
Published: April 2005

Aim

The aim of this study was to evaluate the impact of depression on quality of life in the general population by studying its effects on i) health-related quality of life (HRQoL), ii) health state utilities, and iii) the burden of disease in the population according to age, sex, marital status, education, economy and employment.

Methods

Cross-sectional survey in the County of Uppsala, Sweden. A statistical sample of the general population aged 20–64 years (N = 4506) was used. Information on current state of depression was obtained by self-report. HRQoL was measured using Short Form 36 (SF-36). The time trade-off (TTO) method was used to measure health state utilities. The decrease of total health state utilities associated with depression in the population was used as a measure of burden of disease.

Results

Depression was reported by 4.0% of the population. Those with depression scored significantly lower (P < 0.001) than those without on all eight of the SF-36 domains. The depressed group also rated their health state utilities significantly lower than the others: 0.796 versus 0.933 (P < 0.001). In the multivariate analysis of decrease in utilities with various medical disorders, depression was associated with the greatest decrease (–0.090, P < 0.001). Persons with depression accounted for 10.9% of the total decrease in utilities in the whole population, but this proportion varied according to the specific subgroup. For example, 16.4% and 8.6% of the total burden of disease was linked to depression among single and married people, respectively. The corresponding figures for those with the lowest and highest incomes were 15.0% and 7.9%, respectively. Among the unemployed, persons reporting depression accounted for 15.3% of the decrease in utilities in contrast to 4.9% among the employed.

Conclusions

Depression has a strong impact on the quality of life and total disability in the general population. Further, the impact of depression is unevenly distributed in the population.
The influence of tilt angle on the acoustic target strength of the Japanese common squid (Todarodes pacificus)
Authors: Kang Donhyug , Mukai Tohru , Iida Kohji , Hwang Doojin , Myoung Jung-Goo
Published: April 2005

To measure the influence of changes in tilt angle on the acoustic target strength (TS) of the Japanese common squid (Todarodes pacificus), we conducted a series of experiments to estimate TS in relation to tilt angle and swimming angle. Swimming angle was measured in a seawater tank using two infrared, underwater cameras under dark conditions. Ex situ measurements of TS in relation to tilt angle on live specimens using a fishhook and cage method were then conducted at 38 and 120 kHz; mantle length (ML) ranged from 21 to 27 cm (mean 24.75 cm). For the more precise TS measurement with tilt angle, another set of ex situ TS measurements relative to tilt angle was made at 38 and 120 kHz on tethered, anesthetized specimens in seawater. The mean swimming angle was −17.7° (±12.7° s.d.). The mean TS varied from −48.6 to −44.6 dB and was relatively higher at 120 kHz than at 38 kHz, in the order of 0.7 and 2.5 dB. The empirical relationship between TS (dB) and ML (cm) is given by TS = 20 log10(ML) − 75.4 (r = 0.81) at 38 kHz or TS = 20 log10(ML) − 73.5 (r = 0.64) at 120 kHz. Based on the tethered method for the anesthetized squid, the mean standardized TS values (b20) were found to be highly correlated with the tilt angle, and the resultant fitted equations for b20 were expressed as: b20 = −73.3 + 0.48 × Θ + 0.0122 × Θ2 + 0.00016 × Θ3 for 38 kHz and b20 = −72.6 + 0.53 × Θ + 0.0134 × Θ2 + 0.00014 × Θ3 for 120 kHz, where Θ is the negative tilt angle in degrees. The mean TS based on the measurements using live squid was higher than that of tethered measurements, i.e., 2.6 dB at 38 kHz and 4.0 dB at 120 kHz. The higher mean TS in the ex situ measurements for the live squid can be explained by the influence of the low tilt angle on the overall TS data. The results can be used to understand the influence of tilt angle on the TS of Todarodes pacificus and thus improve the accuracy of biomass estimates.
“LE REGARD ÉLOIGNÉ” EURASIA IN THE PERSPECTIVE OF JACK GOODY
Authors: HANN CHRISTOPHER
Published: April 2005

TWO NEW, COMPLEMENTARY ESSAYS BY JACK GOODY together add up to an impressive call for a general reorientation of academic perspectives concerning the mythologies and hypocrisies of “the West”. In addition to a detailed survey of the recent literature on the topic, each volume is also full of entertaining digressions, some of a personal nature, which provide insight into the long-term intellectual agenda of a remarkable scholar. In the course of this review I shall draw attention to some of the most pertinent of his earlier publications, in which themes touched upon in these high-level syntheses are explored more fully.
PUTTING C. WRIGHT MILLS IN HIS PLACE
Authors: BREWER JOHN D.
Published: April 2005

CHARLES WRIGHT MILLS commands a footnote in the history of sociology. With the exception of The Sociological Imagination, his work is largely forgotten save for a diminishing band of devotees, for whom he remains iconic. Following his early death in 1962, at the age of 46, there was a spate of studies reviewing his work, which simultaneously rendered this rebel into a more benign figure and sanctified him. Sociology as a discipline however, tends to quickly forget its lesser gods and consider them only as part of its past. Citations to this kind of sociologist tend to fall off rapidly when they die, although routinely they are rediscovered half a lifetime later. Renewed assessments of C. Wright Mills's life and career have followed publication over the last decade of large parts of the archive of his private letters, giving the re-engagement with Mills a pronounced biographical focus.
Tick lectins: structural and functional properties
Authors: GRUBHOFFER L. , KOVÁŘ V. , RUDENKO N.
Published: April 2005

Few papers have been published on tick lectins so far, and therefore more data are needed to complete the mosaic of knowledge of their structural and functional properties. Tissue-specific lectin/haemagglutinin activities of both soft and hard ticks have been investigated. Some tick lectins are proteins with binding affinity for sialic acid, various derivatives of hexosamines and different glycoconjugates. Most tick lectin/haemagglutinin activities are blood meal enhanced, and could serve as molecular factors of self/non-self recognition in defence reactions against bacteria or fungi, as well as in pathogen/parasite transmission. Dorin M, the plasma lectin ofOrnithodoros moubata, is the first tick lectin purified so far from tick haemolymph, and the first that has been fully characterized. Partial characterization of other tick lectins/haemagglutinins has been performed mainly with respect to their carbohydrate binding specificities and immunochemical features.
Tick ecology: processes and patterns behind the epidemiological risk posed by ixodid ticks as vectors
Authors: RANDOLPH S. E.
Published: April 2005

The population ecology of ticks is fundamental to the spatial and temporal variation in the risk of infection by tick-borne pathogens. Tick population dynamics can only be fully understood by quantifying the rates of the demographic processes, which are influenced by both abiotic (climatic) factors acting on the free-living tick stages and biotic (host) responses to the tick as a parasite. Within the framework of a population model, I review methods and results of attempts to quantify (1) rates of tick development and the probability of diapause, (2) the probability of questing for hosts by unfed ticks, (3) the probability of ticks attaching to a host, and (4) tick mortality rates. Biologically, these processes involve the physiological and behavioural response of ticks to temperature, moisture stress and day length that result in specific patterns of seasonal population dynamics and host relationships. Temperate and tropical patterns will be illustrated with reference mostly toIxodes ricinusandRhipicephalus appendiculatus, respectively.
Systematics and evolution of ticks with a list of valid genus and species names
Authors: BARKER S. C. , MURRELL A.
Published: April 2005

In recent years there has been much progress in our understanding of the phylogeny and evolution of ticks, in particular the hard ticks (Ixodidae). Indeed, a consensus about the phylogeny of the hard ticks has emerged which is quite different to the working hypothesis of 10 years ago. So that the classification reflects our knowledge of ticks, several changes to the nomenclature of ticks are imminent or have been made. One subfamily, the Hyalomminae, should be sunk, while another, the Bothriocrotoninae, has been created (Klompen, Dobson & Barker, 2002). Bothriocrotoninae, and its sole genusBothriocroton, have been created to house an early-diverging (‘basal’) lineage of endemic Australian ticks that used to be in the genusAponomma. The remaining species of the genusAponommahave been moved to the genusAmblyomma. Thus, the nameAponommais no longer a valid genus name. The genusRhipicephalusis paraphyletic with respect to the genusBoophilus. Thus, the genusBoophilushas become a subgenus of the genusRhipicephalus(Murrell & Barker, 2003). Knowledge of the phylogenetic relationships of ticks has also provided new insights into the evolution of ornateness and of their life cycles, and has allowed the historical zoogeography of ticks to be studied. Finally, we present a list of the 899 valid genus and species names of ticks as of February 2004.
Hormonal control of tick development and reproduction
Authors: REES H. H.
Published: April 2005

Ecdysteroids (moulting hormones), juvenoids and neuropeptides in ticks are reviewed but, by far, the emphasis is on the former since this class of hormones has been the subject of most investigations. In immature stages of ticks, ecdysteroids have been shown to regulate moulting and to terminate larval diapause. Although there is a paucity of information on the molecular action of ecdysteroids in ticks, their action appears to be via a heterodimeric ecdysone/ultraspiracle receptor, as in insects. The role of ecdysteroids in sperm maturation in adult males is considered. In females, ecdysteroids function in the regulation of salivary glands, of production of sex pheromones and of oogenesis and oviposition. There is evidence for ecdysteroid production in the integument and pathways of hormone inactivation are similar to those in insects. Ecdysteroids also function in embryogenesis. Although evidence for the occurrence and functioning of juvenile hormones in ticks has been contradictory, in recent thorough work it has not been possible to detect known juvenile hormones in ticks, nor to demonstrate effects of extracts on insects. Factors (neuropeptides) from the synganglion affect physiological processes and limited immunocytochemical studies are reviewed. Sigificantly, a G-protein-coupled receptor has been cloned, expressed, and specifically responds to myokinins.
Tick salivary glands: function, physiology and future
Authors: BOWMAN A. S. , SAUER J. R.
Published: April 2005

The salivary glands are the organs of osmoregulation in ticks and, as such, are critical to the biological success of ticks both during the extended period off the host and also during the feeding period on the host. Absorption of water vapour from unsaturated air into hygroscopic fluid produced by the salivary glands permit the tick to remain hydrated and viable during the many months between blood-meals. When feeding, the tick is able to return about 70% of the fluid and ion content of the blood-meal into the host by salivation into the feeding site. This saliva also contains many bioactive protein and lipid components that aid acquisition of the blood-meal. The salivary glands are the site of pathogen development and the saliva the route of transmission. The importance of the multifunctional salivary glands to tick survival and vector competency makes the glands a potential target for intervention. Here we review the cell biology of tick salivary glands and discuss the application of new approaches such as expressed sequence tag projects and RNA interference to this important area in the field of tick and tick-borne pathogen research.
Computation of geometric partial differential equations and mean curvature flow
Authors: Deckelnick Klaus , Dziuk Gerhard , Elliott Charles M.
Published: April 2005

This review concerns the computation of curvature-dependent interface motion governed by geometric partial differential equations. The canonical problem of mean curvature flow is that of finding a surface which evolves so that, at every point on the surface, the normal velocity is given by the mean curvature. In recent years the interest in geometric PDEs involving curvature has burgeoned. Examples of applications are, amongst others, the motion of grain boundaries in alloys, phase transitions and image processing. The methods of analysis, discretization and numerical analysis depend on how the surface is represented. The simplest approach is when the surface is a graph over a base domain. This is an example of a sharp interface approach which, in the general parametric approach, involves seeking a parametrization of the surface over a base surface, such as a sphere. On the other hand an interface can be represented implicitly as a level surface of a function, and this idea gives rise to the so-called level set method. Another implicit approach is the phase field method, which approximates the interface by a zero level set of a phase field satisfying a PDE depending on a new parameter. Each approach has its own advantages and disadvantages. In the article we describe the mathematical formulations of these approaches and their discretizations. Algorithms are set out for each approach, convergence results are given and are supported by computational results and numerous graphical figures. Besides mean curvature flow, the topics of anisotropy and the higher order geometric PDEs for Willmore flow and surface diffusion are covered.
Random matrix theory
Authors: Edelman Alan , Rao N. Raj
Published: April 2005

Random matrix theory is now a big subject with applications in many disciplines of science, engineering and finance. This article is a survey specifically oriented towards the needs and interests of a numerical analyst. This survey includes some original material not found anywhere else. We include the important mathematics which is a very modern development, as well as the computational software that is transforming the theory into useful practice.
Inverse analysis of the role of soil vertical heterogeneity in controlling surface soil state and energy partition
Authors: Yang Kun , Koike Toshio , Ye Baisheng , Bastidas Luis
Published: April 2005

Surface soil moisture and temperature have been widely addressed in land surface processes modeling and satellite remote sensing because they play a key role in land surface energy and water budget. However, it is rather difficult for some land surface models to reproduce the surface soil state in areas with high soil vertical heterogeneity because these models use a single parameter set to characterize soil hydraulic and thermal processes. This study develops a single‐source land surface model to parameterize this heterogeneity. Its soil parameters are inversely estimated by minimizing a cost function that is objectively determined by the discrepancy between observed and model‐predicted values of soil moisture and temperature. The approach is then used to investigate how the soil vertical heterogeneity affects subsurface processes and thus controls soil surface state and surface energy budget. This approach is applied to a synthetic numerical experiment and a Tibet field experiment, where the horizontal heterogeneity can be neglected. We indicate that (1) vertical heterogeneous soils cannot be effectively approximated by vertically homogenous soils in a land surface model no matter how the soil parameters are adjusted; (2) soil vertical heterogeneity obviously affects soil subsurface processes and plays a very important role in controlling surface soil wetness and surface energy partition; and (3) in particular, the existence of dense vegetation roots in topsoils may significantly reduce thermal conductivity, increase soil water potential, and enhance surface evaporation. We therefore conclude that it is indispensable to take the soil vertical heterogeneity into account in land surface models, although some of them still assume vertically uniform soil parameters.
Long‐term record of lidar observations of the stratospheric aerosol layer at Garmisch‐Partenkirchen
Authors: Jäger Horst
Published: April 2005

The record of lidar observations of the stratospheric aerosol layer at Garmisch‐Partenkirchen from 1976 to 1999 reflects the natural variability of this layer at northern midlatitudes. The time series of particle backscatter measurements is characterized by volcanic perturbations in the 1980s and 1990s and has captured three periods of low aerosol loading. The discussion of unperturbed and perturbed periods is based on backscatter data and on particle mass and optical depth data derived from backscatter measurements. Similar nonvolcanic or background conditions were observed in the late 1970s and late 1990s. Outstanding events were the perturbations after the tropical eruptions of El Chichón, Mexico, in 1982 and Pinatubo, Philippines, in 1991. When analyzing the decay in stratospheric aerosol loading caused by these two major perturbations, patterns emerge that differ distinctly from each other when starting the comparison with the year of the respective eruption. The observed differences disappear after synchronizing the respective phases of the equatorial quasi‐biennial oscillation (QBO) following these two eruptions. This occurs when the Pinatubo decay of 1993–1995 is compared with the El Chichón decay of 1983–1985. Similar QBO phases suggest that in the winters 1982/1983, 1984/1985, 1992/1993, and 1994/1995, comparable transport patterns out of the tropics lead to increased aerosol concentrations at northern midlatitudes as observed by lidar at Garmisch‐Partenkirchen.
Variations in the Pacific Decadal Oscillation over the past millennium
Authors: MacDonald Glen M. , Case Roslyn A.
Published: April 2005

Hydrologically sensitive tree‐ring chronologies from Pinus flexilis in California and Alberta were used to produce an AD 993–1996 reconstruction of the Pacific Decadal Oscillation (PDO) and to assess long‐term variability in the PDO's strength and periodicity. The reconstruction indicates that a ∼50 to 70 year periodicity in the PDO is typical for the past 200 years but, was only intermittently a strong mode of variability prior to that. Between AD 1600 and 1800 there is a general absence of significant variability within the 50 to 100 year frequency range. Significant variability within in the frequency range of 50 to 100 years reemerges between AD 1500 and 1300 and AD 1200 to 1000. A prolonged period of strongly negative PDO values between AD 993 and 1300 is contemporaneous with a severe medieval megadrought that is apparent in many proxy hydrologic records for the western United States and Canada.
Dynamics of the major disruption of a DIII-D plasma
Authors: Kruger S. E. , Schnack D. D. , Sovinec C. R.
Published: April 2005

The dynamics of the major disruption of DIII-D discharge 87009 are investigated with the NIMROD code [Sovinec et al., J. Comput. Phys. 195, 355 (2004)]. To explore the time dynamics in a computationally efficient manner, a fixed-boundary equilibrium is used to model the physics of a plasma being heated through an ideal magnetohydrodynamic (MHD) instability threshold. This simulation shows a faster-than-exponential increase in magnetic energy as predicted by analytic theory [Callen et al., Phys. Plasmas 6, 2963 (1999)]. The dynamics of the heat flux loading on the divertor surfaces is explored with an equilibrium that has the plasma beta raised 8.7% above the best equilibrium reconstruction to start above the ideal MHD threshold. The nonlinear evolution of the ideal mode leads to a stochastic magnetic field and parallel heat transport leads to a localization of the heat flux that is deposited on the wall. The structure of the heat flux deposition is dependent upon the magnetic topology that results from the growth of the ideal mode.
Influence of composition on relaxor ferroelectric and electromechanical properties of poly(vinylidene fluoride-trifluoroethylene- chlorofluoroethylene)
Authors: Klein Rob J. , Xia Feng , Zhang Q. M. , Bauer François
Published: April 2005

We investigate the influence of the composition, especially the chlorofluoroethylene content, on the ferroelectric and electromechanical properties of the poly(vinylidene fluoride-trifluoroethylene- chlorofluoroethylene) (PVDF-TrFE-CFE). It was found that increasing the CFE from 0to9mol% gradually converts the normal ferroelectric of the copolymer (in the compositions range of VDF/TrFE mole ratio between 64∕36 to 75∕25) to a relaxor ferroelectric, resulting in a nearly hysteresis free polarization loop and high electrostrictive response. On the other hand, increasing CFE content causes reduction in crystallinity, which will affect the elastic modulus and the induced polarization level of the polymer. These competing effects determine the desired terpolymer compositions for given applications. The electromechanical strain as a function of induced polarization and macropolar phase fraction was modeled by a modified electrostrictive relation, which closely matches experimental data. It is found that the electrostrictive coefficient is relatively constant across the compositions investigated.
Oxygen defect and Si nanocrystal dependent white-light and near-infrared electroluminescence of Si-implanted and plasma-enhanced chemical-vapor deposition-grown Si-rich SiO2
Authors: Lin Gong-Ru , Lin Chun-Jung , Lin Chi-Kuan , Chou Li-Jen , Chueh Yu-Lun
Published: April 2005

The mechanisms for silicon (Si) defect and nanocrystal related white and near-infrared electroluminescences (ELs) of Si-rich SiO2 films synthesized by Si-ion implantation and plasma-enhanced chemical-vapor deposition (PECVD) are investigated. The strong photoluminescence (PL) of Si-ion-implanted SiO2 (SiO2:Si+) at 415–455 nm contributed by weak-oxygen bond and neutral oxygen vacancy defects is observed after 1100 °C annealing for 180 min. The white-light EL of a reverse-biased SiO2:Si+ metal-oxide-semiconductor (MOS) diode with a turn-on voltage of 3.3 V originates from the minority-carrier tunneling and recombination in the defect states of SiO2:Si+, which exhibits maximum EL power of 120 nW at bias of 15 V with a power–current slope of 2.2μW∕A. The precipitation of nanocrystallite silicon (nc-Si) in SiO2:Si+ is less pronounced due to relatively small excess Si density. In contrast, the 4-nm nc-Si contributed to PL and EL at about 760 nm is precipitated in the PECVD-grown Si-rich SiOx film after annealing at 1100 °C for 30 min. The indium-tin-oxide/Si-rich SiOx∕p-Si∕Al metal oxide semiconductor (MOS) diode is highly resistive with turn-on voltage and power-current (P–I) slope of 86 V and 0.7mW∕A, respectively. The decomposed EL peaks at 625 and 768 nm are contributed by the bias-dependent cold-carrier tunneling between the excited states in adjacent nc-Si quantum dots.
A simple highly accurate field-line mapping technique for three-dimensional Monte Carlo modeling of plasma edge transport
Authors: Feng Y. , Sardei F. , Kisslinger J.
Published: April 2005

The paper presents a new simple and accurate numerical field-line mapping technique providing a high-quality representation of field lines as required by a Monte Carlo modeling of plasma edge transport in the complex magnetic boundaries of three-dimensional (3D) toroidal fusion devices. Using a toroidal sequence of precomputed 3D finite flux-tube meshes, the method advances field lines through a simple bilinear, forward/backward symmetric interpolation at the interfaces between two adjacent flux tubes. It is a reversible field-line mapping (RFLM) algorithm ensuring a continuous and unique reconstruction of field lines at any point of the 3D boundary. The reversibility property has a strong impact on the efficiency of modeling the highly anisotropic plasma edge transport in general closed or open configurations of arbitrary ergodicity as it avoids artificial cross-field diffusion of the fast parallel transport. For stellarator-symmetric magnetic configurations, which are the standard case for stellarators, the reversibility additionally provides an average cancellation of the radial interpolation errors of field lines circulating around closed magnetic flux surfaces. The RFLM technique has been implemented in the 3D edge transport code EMC3-EIRENE and is used routinely for plasma transport modeling in the boundaries of several low-shear and high-shear stellarators as well as in the boundary of a tokamak with 3D magnetic edge perturbations.
Improved metastable de-excitation spectrometer using laser-cooling techniques
Authors: Pratt Andrew , Roskoss Alexander , Ménard Hervé , Jacka Marcus
Published: April 2005

Details of a new approach for performing metastable de-excitation spectroscopy are given. A beam of metastable (2S3) helium atoms, produced in a hollow cathode dc discharge, is collimated and subsequently focused using Doppler cooling of the 2S13–2P23 transition at 1083nm, forming an intense probe of up to 1×1012atomss−1cm−2. The large distance (2.5m) between source and sample means that the beam is relatively free of UV photons and 2S1 metastable atoms, removing the need for quench lamps and chopper wheels. As well as providing a clean high intensity source, the well defined nature of the beam is a necessary step towards using more sophisticated laser-cooling techniques with the ultimate aim of producing a metastable helium microscope. MDS and UPS spectra from Si(111) are shown.
Cryogenic loading of large volume presses for high-pressure experimentation and synthesis of novel materials
Authors: Lipp M. J. , Evans W. J. , Yoo C. S.
Published: April 2005

We present an efficient, easily implemented method for loading cryogenic fluids in a large volume press. We specifically apply this method to the high-pressure synthesis of an extended solid derived from CO using a Paris–Edinburgh cell. This method employs cryogenic cooling of Bridgman-type WC anvils well insulated from other press components, condensation of the load gas within a brass annulus surrounding the gasket between the Bridgman anvils. We demonstrate the viability of the described approach by synthesizing macroscopic amounts (several milligrams) of polymeric CO-derived material, which were recovered to ambient conditions after compression of pure CO to 5GPa or above.
Absence of a desmopressin response after therapeutic expression of factor VIII in hemophilia A dogs with liver-directed neonatal gene therapy
Authors: Xu Lingfei , Nichols Timothy C. , Sarkar Rita , McCorquodale Stephanie , Bellinger Dwight A. , Ponder Katherine P.
Published: April 2005

Hemophilia A (HA) is a bleeding disorder caused by factor VIII (FVIII) deficiency. FVIII replacement therapy can reduce bleeding but is expensive, inconvenient, and complicated by development of antibodies that inhibit FVIII activity in 30% of patients. Neonatal hepatic gene therapy could result in continuous secretion of FVIII into blood and might reduce immunological responses. Newborn HA mice and dogs that were injected i.v. with a retroviral vector (RV) expressing canine B domain-deleted FVIII (cFVIII) achieved plasma cFVIII activity that was 139 ± 22% and 116 ± 5% of values found in normal dogs, respectively, which was stable for 1.5 yr. Coagulation tests were normalized, no bleeding had occurred, and no inhibitors were detected. This is a demonstration of long-term fully therapeutic gene therapy for HA in a large animal model. Desmopressin (DDAVP; 1-deamino-[
d
-Arg
8
]vasopressin) is a drug that increases FVIII activity by inducing release of FVIII complexed with von Willebrand factor from endothelial cells. It has been unclear, however, if the FVIII is synthesized by endothelial cells or is taken up from blood. Because the plasma cFVIII in these RV-treated dogs derives primarily from transduced hepatocytes, they provided a unique opportunity to study the biology of the DDAVP response. Here we show that DDAVP did not increase plasma cFVIII levels in the RV-treated dogs, although von Willebrand factor was increased appropriately. This result suggests that the increase in FVIII in normal dogs after DDAVP is due to release of FVIII synthesized by endothelial cells.
Genetic variance in female condition predicts indirect genetic variance in male sexual display traits
Authors: Petfield Donna , Chenoweth Stephen F. , Rundle Howard D. , Blows Mark W.
Published: April 2005

During sexual encounters, individuals often use signals, such as display traits, to attract mates. If individuals alter their display traits with respect to the genotype of potential mates, indirect genetic effects (IGEs) may occur in which the genes of one individual influence the phenotype of another. Although IGEs between related individuals have received much attention, their occurrence between unrelated individuals during sexual encounters has not. Here, we demonstrate that in the Australian fruit fly
Drosophila serrata
, males assess females by using both visual and olfactory cues, resulting in a rapid plastic response (within minutes) in male cuticular hydrocarbons (CHCs), a display trait that is an important target of mate choice. Several CHCs in males exhibited significant IGEs, and IGEs were inducible on both males reared in the laboratory and on field-caught individuals. A vector describing genetic variance in multiple CHCs in females was found to be almost identical to a vector describing indirect genetic variance in male CHCs, suggesting that males might assess female CHCs during courtship. This vector displayed contributions from all female CHCs in the same direction and of similar magnitude, suggesting that female condition may be the underlying casual trait that males are assessing. Consistent with this interpretation, when measured directly in a separate experiment, genetic variance in female condition accounted for 19.8% of the indirect genetic variance in male CHCs. These indirect genetic effects have the potential to alter the response to selection of male sexual display traits.
Structural basis for the interaction of Asf1 with histone H3 and its functional implications
Authors: Mousson Florence , Lautrette Aurélie , Thuret Jean-Yves , Agez Morgane , Courbeyrette Régis , Amigues Béatrice , Becker Emmanuelle , Neumann Jean-Michel , Guerois Raphaël , Mann Carl , Ochsenbein Françoise
Published: April 2005

Asf1 is a conserved histone chaperone implicated in nucleosome assembly, transcriptional silencing, and the cellular response to DNA damage. We solved the NMR solution structure of the N-terminal functional domain of the human Asf1a isoform, and we identified by NMR chemical shift mapping a surface of Asf1a that binds the C-terminal helix of histone H3. This binding surface forms a highly conserved hydrophobic groove surrounded by charged residues. Mutations within this binding site decreased the affinity of Asf1a for the histone H3/H4 complex
in vitro
, and the same mutations in the homologous yeast protein led to transcriptional silencing defects, DNA damage sensitivity, and thermosensitive growth. We have thus obtained direct experimental evidence of the mode of binding between a histone and one of its chaperones and genetic data suggesting that this interaction is important in both the DNA damage response and transcriptional silencing.
Folding events in the 21-30 region of amyloid β-protein (Aβ) studied
in silico
Authors: Borreguero Jose M. , Urbanc Brigita , Lazo Noel D. , Buldyrev Sergey V. , Teplow David B. , Stanley H. Eugene
Published: April 2005

Oligomeric assemblies of the amyloid β-protein (Aβ) have been implicated in the pathogenesis of Alzheimer's disease as a primary source of neurotoxicity. Recent
in vitro
studies have suggested that a 10-residue segment, Ala-21-Ala-30, forms a turn-like structure that nucleates the folding of the full-length Aβ. To gain a mechanistic insight, we simulated Aβ(21-30) folding by using a discrete molecular dynamics algorithm and a united-atom model incorporating implicit solvent and a variable electrostatic interaction strength (EIS). We found that Aβ(21-30) folds into a loop-like conformation driven by an effective hydrophobic attraction between Val-24 and the butyl portion of the Lys-28 side chain. At medium EIS [1.5 kcal/mol (1 cal = 4.18 J)], unfolded conformations almost disappear, in agreement with experimental observations. Under optimal conditions for folding, Glu-22 and Asp-23 form transient electrostatic interactions (EI) with Lys-28 that stabilize the loop conformations. Glu-22-Lys-28 is the most favored interaction. High EIS, as it occurs in the interior of proteins and aggregates, destabilizes the packing of Val-24 and Lys-28. Analysis of the unpacked structures reveals strong EI with predominance of the Asp-23-Lys-28 interaction, in agreement with studies of molecular modeling of full-length Aβ fibrils. The binary nature of the EI involving Lys-28 provides a mechanistic explanation for the linkage of amino acid substitutions at Glu-22 with Alzheimer's disease and cerebral amyloid angiopathy. Substitutions may alter the frequency of Glu-22 or Asp-23 involvement in contact formation and affect the stability of the folding nucleus formed in the Aβ(21-30) region.
Efficient formation of bipolar microtubule bundles requires microtubule-bound γ-tubulin complexes
Authors: Janson Marcel E. , Setty Thanuja Gangi , Paoletti Anne , Tran P.T.
Published: April 2005

The mechanism for forming linear microtubule (MT) arrays in cells such as neurons, polarized epithelial cells, and myotubes is not well understood. A simpler bipolar linear array is the fission yeast interphase MT bundle, which in its basic form contains two MTs that are bundled at their minus ends. Here, we characterize mto2p as a novel fission yeast protein required for MT nucleation from noncentrosomal γ-tubulin complexes (γ-TuCs). In interphase mto2Δ cells, MT nucleation was strongly inhibited, and MT bundling occurred infrequently and only when two MTs met by chance in the cytoplasm. In wild-type 2, we observed MT nucleation from γ-TuCs bound along the length of existing MTs. We propose a model on how these nucleation events can more efficiently drive the formation of bipolar MT bundles in interphase. Key to the model is our observation of selective antiparallel binding of MTs, which can both explain the generation and spatial separation of multiple bipolar bundles.
eIF4E promotes nuclear export of cyclin D1 mRNAs via an element in the 3′UTR
Authors: Culjkovic Biljana , Topisirovic Ivan , Skrabanek Lucy , Ruiz-Gutierrez Melisa , Borden Katherine L.B.
Published: April 2005

The eukaryotic translation initiation factor eIF4E is a critical modulator of cellular growth with functions in the nucleus and cytoplasm. In the cytoplasm, recognition of the 5′ m7G cap moiety on all mRNAs is sufficient for their functional interaction with eIF4E. In contrast, we have shown that in the nucleus eIF4E associates and promotes the nuclear export of cyclin D1, but not GAPDH or actin mRNAs. We determined that the basis of this discriminatory interaction is an ∼100-nt sequence in the 3′ untranslated region (UTR) of cyclin D1 mRNA, we refer to as an eIF4E sensitivity element (4E-SE). We found that cyclin D1 mRNA is enriched at eIF4E nuclear bodies, suggesting these are functional sites for organization of specific ribonucleoproteins. The 4E-SE is required for eIF4E to efficiently transform cells, thereby linking recognition of this element to eIF4E mediated oncogenic transformation. Our studies demonstrate previously uncharacterized fundamental differences in eIF4E-mRNA recognition between the nuclear and cytoplasmic compartments and further a novel level of regulation of cellular proliferation.
Transcriptional regulation of myotube fate specification and intrafusal muscle fiber morphogenesis
Authors: Albert Y'vonne , Whitehead Jennifer , Eldredge Laurie , Carter John , Gao Xiaoguang , Tourtellotte Warren G.
Published: April 2005

Vertebrate muscle spindle stretch receptors are important for limb position sensation (proprioception) and stretch reflexes. The structurally complex stretch receptor arises from a single myotube, which is transformed into multiple intrafusal muscle fibers by sensory axon–dependent signal transduction that alters gene expression in the contacted myotubes. The sensory-derived signal transduction pathways that specify the fate of myotubes are very poorly understood. The zinc finger transcription factor, early growth response gene 3 (Egr3), is selectively expressed in sensory axon–contacted myotubes, and it is required for normal intrafusal muscle fiber differentiation and spindle development. Here, we show that overexpression of Egr3 in primary myotubes in vitro leads to the expression of a particular repertoire of genes, some of which we demonstrate are also regulated by Egr3 in developing intrafusal muscle fibers within spindles. Thus, our results identify a network of genes that are regulated by Egr3 and are involved in intrafusal muscle fiber differentiation. Moreover, we show that Egr3 mediates myotube fate specification that is induced by sensory innervation because skeletal myotubes that express Egr3 independent of other sensory axon regulation are transformed into muscle fibers with structural and molecular similarities to intrafusal muscle fibers. Hence, Egr3 is a target gene that is regulated by sensory innervation and that mediates gene expression involved in myotube fate specification and intrafusal muscle fiber morphogenesis.
Integral structures in the 𝑝-adic holomorphic discrete series
Authors: Grosse-Klönne Elmar
Published: April 2005

For a local non-Archimedean field

K
K

we construct

G
L

d
+
1

(
K
)

{\mathrm {GL}}_{d+1}(K)

-equivariant coherent sheaves

V

O

K

{\mathcal V}_{{\mathcal O}_K}

on the formal

O

K

{\mathcal O}_K

-scheme

X

{\mathfrak X}

underlying the symmetric space

X
X

over

K
K

of dimension

d
d

. These

V

O

K

{\mathcal V}_{{\mathcal O}_K}

are

O

K

{\mathcal O}_K

-lattices in (the sheaf version of) the holomorphic discrete series representations (in

K
K

-vector spaces) of

G
L

d
+
1

(
K
)

{\mathrm {GL}}_{d+1}(K)

as defined by P. Schneider. We prove that the cohomology

H
t

(

X

,

V

O

K

)

H^t({\mathfrak X},{\mathcal V}_{{\mathcal O}_K})

vanishes for

t
>
0

t>0

, for

V

O

K

{\mathcal V}_{{\mathcal O}_K}

in a certain subclass. The proof is related to the other main topic of this paper: over a finite field

k
k

, the study of the cohomology of vector bundles on the natural normal crossings compactification

Y
Y

of the Deligne-Lusztig variety

Y
0

Y^0

for

G
L

d
+
1

/

k

{\mathrm {GL}}_{d+1}/k

(so

Y
0

Y^0

is the open subscheme of

P

k
d

{\mathbb P}_k^d

obtained by deleting all its

k
k

-rational hyperplanes).
The solution structure of PapGII from uropathogenic Escherichia coli and its recognition of glycolipid receptors
Authors: Sung Mei‐an , Fleming Keiran , Chen Ho An , Matthews Stephen
Published: April 2005

Uropathogenic Escherichia coli (UPEC) is the primary cause of symptomatic urinary tract infection. The P‐pili, a bacterial surface organelle, mediates the bacterial host–cell adhesion. The PapG adhesin has generated much interest in recent years, not only because of its clinical value, i.e. in the prevention of microbial adherence, but also because of its ability to promote virulence. Using multidimensional nuclear magnetic resonance (NMR) and deuteration we have determined the solution structure of the adhesin domain from PapGII (PapGII‐198). The novel structure of PapGII‐198 is composed of a large elongated jellyroll motif. Despite an automated search of the structural database failing to reveal any similar proteins, PapGII adhesin shares some structural similarities with FimH. Furthermore, interpretation of NMR‐titration data has enabled us to identify the putative binding site for the globoseries of oligosaccharides. This work provides insight into UPEC pathogenesis as well as aiding the development of preventative therapies and the guidance of future mutagenesis programmes.
Human stoned B interacts with AP‐2 and synaptotagmin and facilitates clathrin‐coated vesicle uncoating
Authors: Walther Kristin , Krauss Michael , Diril M Kasim , Lemke Steffen , Ricotta Doris , Höning Stefan , Kaiser Stephen , Haucke Volker
Published: April 2005

Synaptic vesicle biogenesis involves the recycling of synaptic vesicle components by clathrin‐mediated endocytosis from the presynaptic membrane. stoned B, a protein encoded by the stoned locus in Drosophila melanogaster has been shown to regulate vesicle recycling by interacting with synaptotagmin. We report here the identification and characterization of a human homolog of stoned B (hStnB). Human stoned B is a brain‐specific protein which co‐enriches with other endocytic proteins such as AP‐2 in a crude synaptic vesicle fraction and at nerve terminals. A domain with homology to the medium chain of adaptor complexes binds directly to both AP‐2 and synaptotagmin and competes with AP‐2 for the same binding site within synaptotagmin. Finally we show that the μ2 homology domain of hStnB stimulates the uncoating of both clathrin and AP‐2 adaptors from clathrin‐coated vesicles. We hypothesize that hStnB regulates synaptic vesicle recycling by facilitating vesicle uncoating.