bluuebunny/crossref_metadata_2025 huggingface dataset:
Charlatan, a Zn-finger transcription factor, establishes a novel level of regulation of the proneuralachaete/scutegenes ofDrosophila
Authors: Escudero Luis M. , Caminero Eva , Schulze Karen L. , Bellen Hugo J. , Modolell Juan
Published: February 2005

The proneural genes achaete (ac) and scute(sc) are necessary for the formation of the external sensory organs(SOs) of Drosophila. ac and sc are expressed in proneural clusters and impart their cells with neural potential. For this potential to be realized, and the SO precursor cell (SOP) to arise within a cluster, sufficient proneural protein must accumulate in the cluster. Here we describe a novel gene, charlatan (chn), which encodes a zinc finger transcription factor that facilitates this accumulation by forming a stimulatory loop with ac/sc. We find that loss of function of chn decreases the accumulation of Sc in proneural clusters and partially removes notum macrochaetae, while overexpression of chnenhances ac/sc expression and the formation of extra SOs. Moreover, chn is activated by ac/sc in proneural clusters. Chn apparently stimulates ac/sc by physically interacting with the proneural cluster-specific enhancers and increasing enhancer efficiency, thus acting as a stimulator of ac/sc expression in proneural clusters. chn is also required for the proper development of the embryonic peripheral nervous system, as its absence leads to loss of neurons and causes aberrant development of chordotonal organs.
Functional specificity of shuttling hnRNPs revealed by genome-wide analysis of their RNA binding profiles
Authors: KIM GUISBERT KAREN , DUNCAN KENT , LI HAO , GUTHRIE CHRISTINE
Published: February 2005

Nab2, Npl3, and Nab4/Hrp1 are essential RNA binding proteins of the shuttling hnRNP class that are required for the efficient export of mRNA. To characterize the in vivo transcript specificity of these proteins, we identified their mRNA binding partners using a microarray-based assay. Each of the three proteins was coimmunoprecipitated with many different mRNA transcripts. Interestingly, each protein exhibits preferential associations with a distinct set of mRNAs. Notably, some of these appear to denote specific functional classes. For example, the ribosomal protein mRNAs and other highly expressed transcripts significantly favor association with Npl3 over Nab2, and Nab4/Hrp1 is strongly enriched with transcripts required for amino acid metabolism. Significantly, nab4 mutants showed a striking, desensitized growth phenotype when exposed to amino acid stress conditions suggesting a biological consequence to the associations we observed. Supporting the hypothesis that these proteins display transcript specificity, we identified a unique 7-nucleotide sequence overrepresented in the transcripts highly associated with Nab2 and Nab4/Hrp1 using the REDUCE algorithm. Validating our approach, our bioinformatics analysis correctly identified the known binding site for Nab4/Hrp1. These specialized associations of the hnRNP proteins of Saccharomyces cerevisiae suggest the opportunity to regulate the processing of particular transcripts between transcription and translation.
Horizontal Coefficient of Consolidation of Soft Bangkok Clay
Authors: Seah TH , Tangthansup B , Wongsatian P
Published: February 2005

This paper presents the results of the coefficient of consolidation in the horizontal direction determined from the laboratory and the field through testing, along with back analysis from settlement measurement of embankment constructed with prefabricated vertical drains at the Suvarnabhumi Airport site in Bangkok. Constant rate of strain consolidation tests with radial drainage and standard oedometer tests were conducted to provide the consolidation characteristics of soft Bangkok clay. A 20-mm piezoprobe was used to measure the pore water pressure dissipation characteristics of the soft clay in the field, and the corresponding horizontal coefficients of consolidation were estimated based on established theory. The test results, such as the horizontal coefficients of consolidation and permeability, were compared with back analysis of the constructed runway embankment based on Asaoka method. The results show very good agreement in both horizontal coefficients of consolidation and permeability obtained from different testing methods and back analysis, implying the reliability of the testing methods adopted.
Knotting and Threading of Molecules: Chemistry and Chirality of Molecular Knots and Their Assemblies
Authors: Lukin Oleg , Vögtle Fritz
Published: February 2005

How and why do molecules tangle or thread? Investigations of molecular knots (knotanes) may shed some light on the mechanisms of (supra)molecular templation and the folding of molecules that result in intertwining. The topological chirality of these fascinating molecules leads to new types of isomerism and paves the way to nanosized molecular motors. Their preparation and derivatization makes high demands on modern synthetic methods and analytical separation since molecular knots are formed in a more or less planned design based on metal coordination or hydrogen‐bonding patterns. This Review describes the development of templation techniques for the synthesis of knotanes and their chiral resolution as well as their selective functionalization and use as building blocks in the synthesis of higher knotane assemblies. Such assemblies can possess linear, branched, or even macrocyclic structures which, on the one hand, introduce unprecedented isomeric compositions that arise from multiple topological stereogenic units and, on the other, define new types of artificial macromolecules beyond polymers and dendritic species.
Utilizing three‐dimensional wavelet transforms for accelerated evaluation of hyperspectral image cubes
Authors: Vogt Frank , Banerji Soame , Booksh Karl
Published: February 2005

Hyperspectral imaging sensors are continuously enhanced by increasing spatial and spectral resolution. However, the ‘curse of dimensionality’ comes into effect, as the amount of acquired data increases in third order (two spatial, one spectral dimension). On top of that, the computational expense of many chemometric data evaluation techniques such as principal component analysis (PCA) rises also in third order with the data amount. Thus the need for computer memory is increased in third and the demand for computational power up to ninth order. One immediate consequence of massively increased computation times is a decreased time resolution of hyperspectral imagers, which is especially detrimental in online applications. Archiving humongous amounts of data becomes another burden. Thus it is anticipated that increased computation resources alone will not be able to facilitate fast online evaluation of hyperspectral data cubes or even to handle the acquired data. In this study, 3D wavelet transforms are used for compression of hyperspectral data cubes prior to chemometric data evaluation and/or data storage. Five different wavelet types of the Daubechies family are compared with respect to their ability to preserve relevant information in compressed data cubes. Because only relevant information has to be considered, shorter computation time and less storage space are required. By means of experimental hyperspectral data cubes it is demonstrated that additional computation expense for the 3D wavelet transform is largely overcompensated by reduced calculations necessitated by smaller data cubes. In the presented examples, computation time for a PCA could be decreased by one order of magnitude; storage space could be reduced to <1% of the original size. It was found that the wavelet type has a major influence on the acceleration factors. Copyright © 2005 John Wiley & Sons, Ltd.
Sample‐specific standard prediction errors in three‐way parallel factor analysis (PARAFAC) exploiting the second‐order advantage
Authors: Olivieri Alejandro C.
Published: February 2005

The calculation of sample‐specific standard errors for the concentrations predicted by a three‐way parallel factor analysis (PARAFAC) model exploiting the second‐order advantage is discussed. A simple error propagation equation is shown to be useful for this purpose, on the condition that the correct sensitivity parameter is introduced. Two different net analyte signal definitions are tested for measures of sensitivity and are demonstrated to be applicable to different calibration scenarios, namely whether or not the second‐order advantage is exploited. The results are supported by Monte Carlo calculations of variance inflation factors (including random noise only in the test sample signals) and also by experimental data concerning the determination of a therapeutic drug in human urine samples by fluorescence excitation–emission matrices. Full Monte Carlo simulations performed by adding random noise to both concentrations and instrumental signals (calibration and unknown) in several theoretical binary mixtures are in good agreement with the proposed approach. Copyright © 2005 John Wiley & Sons, Ltd.
Looking for the right thing at the right place: Phase transition in an agent model with heterogeneous spatial resources
Authors: Boyer Denis , Larralde Hernán
Published: February 2005

We introduce a simple model describing an agent traveling within a medium containing resources randomly distributed in space. The agent, initially located at some origin, performs a single step toward a target of his choice that minimizes an economy function. We use an economy function that depends on the weight of the target and its distance from the origin. The cost and length statistics of the displacements are analyzed. We find a critical point for a particular resource weight distribution, such that the average cost vanishes (or becomes very small in practice). This problem can describe an economical agent looking for a firm with the best price or largest product choice, a tourist in search of an interesting and nearby city to visit, or an animal foraging in a complex landscape. © 2005 Wiley Periodicals, Inc. Complexity 10: 52–55, 2005
Evolutionary origins and principles of distributed neural computation for state estimation and movement control in vertebrates
Authors: Paulin Michael G.
Published: February 2005

Vertebrates are mostly large, agile creatures that can move rapidly and efficiently despite the significant inertial and interaction forces that are generated when they move. Vertebrates appear in the fossil record in the lower Cambrian, when predation began to apply selection pressure for increased size and, consequently, increased inertia. Agility depends critically upon the cerebellum, a brain structure that appears to have evolved as an elaboration of the vestibular and lateral‐line sensory processing regions in brains of aquatic ancestors. There is compelling evidence to suggest that the specific role of the cerebellum in motor control (etc) is state estimation. Analysis of responses of vestibular neurons in bullfrogs shows that these neurons have fractional‐order dynamics. Because of this property, the vestibular nerve forms a map of the state space of the animal's head, and individual action potentials can be regarded as assertions about the location of the head in that space. This view of vestibular coding suggests an analogy with particle filters, a new simulation‐based method for state estimation. In a particle filter the distribution of possible states consistent with observations is represented by a cloud of “particles” in a map of the state space. By regarding action potentials as particles in neural state estimators, we may develop a realistic model of neural computation in the cerebellum. At the same time—and independently of the biological verisimilitude of such a cerebellar model—we may develop useful new algorithms for state estimation. © 2005 Wiley Periodicals, Inc. Complexity 10: 56–65, 2005
Addition of Indole to Methyl 2‐Chloro‐2‐cyclopropylideneacetate en Route to Spirocyclopropanated Analogues of Demethoxyfumitremorgine C and Tadalafil
Authors: Limbach Michael , Dalai Suryakanta , Janssen André , Es‐Sayed Mazen , Magull Jörg , de Meijere Armin
Published: February 2005

Indole readily added across the double bond of the highly reactive Michael acceptor methyl 2‐chloro‐2‐cyclopropylideneacetate (4) to yield 2‐chloro‐2‐(3′‐indolylcyclopropyl)acetate 5 (85%) which was converted in two steps into the racemic tryptophan analogue 7 in 90% yield. This in turn was transformed by a condensation and Pictet−Spengler sequence into the spirocyclopropane analogues, 11, 13 and 15, of both the natural product (demethoxy)fumitremorgine C (3b, 3 steps, 11% yield) and the potent PDE‐5 inhibitor Tadalafil (2, 3 steps, 71% yield) as well as the original lead structure with a hydantoin backbone (1, 2 steps, 79% yield). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Chemical modification of chicken egg white proteins with polyethyleneoxide–maleic anhydride copolymer and their partitioning in aqueous two‐phase systems
Authors: Shin‐ya Yoshitsune , Park Jin‐Won , Hong Kyung‐Jin , Fujiwara Koichi , Kajiuchi Toshio
Published: February 2005

Aqueous two‐phase partitioning is one of the excellent bioseparation systems for proteins and other biomolecules in water‐rich solutions containing polymers or salts. To improve the partition properties of model proteins, chicken egg white (CEW) proteins were chemically modified with polyethyleneoxide–maleic anhydride (PEOMA) copolymer. The modified proteins were partitioned in polyethyleneoxide–maleic acid/potassium phosphate aqueous two‐phase systems. Firstly, the contribution of the chemical modification of proteins to the partition coefficient was investigated by using modified proteins with different degrees of modification (DM). The partition coefficients of modified proteins increased with increasing DM. The results suggested that the surface of the modified proteins had a greater hydrophobic property, similar to the PEOMA copolymer. Secondly, the effect of the pH on the partitioning of the modified proteins was studied. The partitioning of the modified proteins was found to be more dependent on pH in the alkaline systems. The increasing partition coefficient with pH at alkaline pH can be explained by the electrostatic repulsion between the phosphate anions and the maleic groups attached to the proteins. These results suggested that chemical modification of proteins with PEOMA could be a useful tool for separation and purification of crude protein mixtures. Copyright © 2005 Society of Chemical Industry
Relative quantitation of peptides in wild‐type and Cpefat/fat mouse pituitary using stable isotopic tags and mass spectrometry
Authors: Che Fa‐Yun , Biswas Reeta , Fricker Lloyd D.
Published: February 2005

Cpefat/fat mice have a point mutation in the coding region of the carboxypeptidase E gene that renders the enzyme inactive. As a result, these mice have reduced levels of several neuropeptides and greatly increased levels of the peptide processing intermediates that contain C‐terminal basic residues. However, previous studies examined a relatively small number of neuropeptides. In the present study, we used a quantitative peptidomics approach with stable isotopic labels to examine the levels of pituitary peptides in Cpefat/fat mice relative to wild‐type mice. Pituitary extracts from mutant and wild type mice were labeled with the stable isotopic label [3‐(2,5‐dioxopyrrolidin‐1‐yloxycarbonyl)propyl]trimethylammonium chloride containing nine atoms of hydrogen or deuterium. Then, the two samples were pooled and analyzed by liquid chromatography/mass spectrometry (LC/MS). The relative abundance of peptides was determined from a comparison of the intensities of the heavy and light peaks. Altogether, 72 peptides were detected in the Cpefat/fat and/or wild‐type mouse pituitary extracts of which 53 were identified by MS/MS sequencing. Several peptides identified in this analysis represent previously undescribed post‐translational processing products of known pituitary prohormones. Of the 72 peptides detected in pituitary, 17 were detected only in the Cpefat/fat mouse extracts; these represent peptide processing intermediates containing C‐terminal basic residues. The peptides common to both Cpefat/fat and wild‐type mice were generally present at 2–5‐fold lower levels in the Cpefat/fat mouse pituitary extracts, although some peptides were present at equal levels and one peptide (acetyl β‐endorphin 1‐31) was increased ∼7‐fold in the Cpefat/fat pituitary extracts. In contrast, acetyl β‐endorphin 1‐26 was present at ∼10‐fold lower levels in the Cpefat/fat pituitary, compared with wild‐type mice. The finding that many peptides are substantially decreased in Cpefat/fat pituitary is consistent with the broad role for carboxypeptidase E in the biosynthesis of numerous neuropeptides. Copyright © 2005 John Wiley & Sons, Ltd.
Sulfonation of Poly(propylene) Films with Fuming Sulfuric Acid
Authors: Kaneko Masashi , Sato Hisaya
Published: February 2005

Summary: Sulfonation is one of the most commonly used methods for the surface modification of polymers. In this study, the sulfonation of poly(propylene) (PP) films with fuming sulfuric acid has been investigated with the focus on the surface reaction. Analysis of the sulfonated PP films by X‐ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) infrared spectroscopy, and chemical modification demonstrated the formation of CC double bonds and sulfate groups in the sulfonation process. These results and a comparison with low‐density polyethylene (LDPE) films led us to propose a new sulfonation mechanism involving hydride abstraction and the formation of β‐sultones.

The here proposed mechanism of the sulfonation of poly(propylene) involves the formation of unstable β‐sultones.

magnified image

The here proposed mechanism of the sulfonation of poly(propylene) involves the formation of unstable β‐sultones.
Surface waves on a grounded double‐negative (DNG) slab waveguide
Authors: Bait Suwailam Mohammed M. , Chen Zhizhang (David)
Published: February 2005

Surface waves are the fields that decay exponentially away from, but propagate along, a dielectric interface. In this paper, a dielectric waveguide is constructed with a grounded DNG metamaterial slab whose real parts of permittivity and permeability are both negative. Field solutions are then derived analytically in terms of propagation dispersion. The results obtained show that the grounded DNG slab waveguide presents properties different from those of the conventional grounded slab waveguide and can be used as a bandpass filter with TE1 mode propagation. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 494–498, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20677
Theoretical analysis of linear active antenna array for beam steering
Authors: Pandey Vijay K. , Vishvakarma Babau R.
Published: February 2005

The beam‐steering characteristic of a 1 × 4 linear Gunn‐integrated active antenna array is investigated by varying the bias voltages of the different elements in the array while keeping the side‐lobe level 10‐dB below the main beam level. By varying the bias voltage of all four elements simultaneously, the optimization of beam steering exhibited a beam scanning of 40° with 1.85‐dB power deviation in the main beam, which is better than the previously reported data. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 560–564, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20697
Preparation and clinical application of immunomagnetic latex
Authors: Wang Ping‐Cheih , Lee Chia‐Fen , Young Tai‐Horng , Lin Dong‐Tsamn , Chiu Wen‐Yen
Published: February 2005

Magnetic poly(methyl methacrylate) (PMMA)/poly(methyl methacrylate‐co‐methacrylic acid) [P(MMA–MAA)] composite polymer latices were synthesized by two‐stage soapless emulsion polymerization in the presence of magnetite (Fe3O4) ferrofluids. Different types and concentrations of fatty acids were reacted with the Fe3O4 particles, which were prepared by the coprecipitation of Fe(II) and Fe(III) salts to obtain stable Fe3O4 ferrofluids. The Fe3O4/polymer particles were monodisperse, and the composite polymer particle size was approximately 100 nm. The morphology of the magnetic composite polymer latex particles was a core–shell structure. The core was PMMA encapsulating Fe3O4 particles, and the shell was the P(MMA–MAA) copolymer. The carboxylic acid functional groups (COOH) of methacrylic acid (MAA) were mostly distributed on the surface of the composite polymer latex particles. Antibodies (anti‐human immunoglobulin G) were then chemically bound with COOH groups onto the surface of the magnetic core–shell composite latices through the medium of carbodiimide to form the antibody‐coated magnetic latices (magnetic immunolatices). The MAA shell composition of the composite latex could be adjusted to control the number of COOH groups and thus the number of antibody molecules on the magnetic composite latex particles. With a magnetic sorting device, the magnetic immunolatices derived from the magnetic PMMA/P(MMA–MAA) core–shell composite polymer latex performed well in cell‐separation experiments based on the antigen–antibody reaction. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1342–1356, 2005
Thermodynamics of reversibly associating ideal chains
Authors: Loverde Sharon M. , Ermoshkin Alexander V. , De La Cruz Monica Olvera
Published: February 2005

Solutions of ideal thermoreversible associating polymer chains are analyzed by standard Metropolis Monte Carlo simulations. The associating units are restricted to form only pairs and are located at the ends of each chain. Two cases are considered: equilibrium chemical association and diffusion limited association. Thermodynamic and structural quantities obtained in the simulations are directly compared to predictions of a mean field theory. Finite size effects when considering loop‐like structures are addressed for the case of equilibrium chemical association. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 796–804, 2005
The hemodynamic and neurohormonal effects of low doses of tezosentan (an endothelin A/B receptor antagonist) in patients with acute heart failure
Authors: Cotter Gad , Kaluski Edo , Stangl Karl , Pacher Richard , Richter Christoph , Milo‐Cotter Olga , Perchenet Loïc , Kobrin Isaac , Kaplan Shoshana , Rainisio Maurizio , Frey Aline , Neuhart Eric , Vered Zvi , Dingemanse Jasper , Torre‐Amione Guillermo
Published: February 2005

Background:

In previous studies (the RITZ project), tezosentan, an intravenous (i.v.)‐balanced dual endothelin (ET‐A/B) antagonist, in doses of 50 and 100 mg/h, improved the hemodynamics but not the clinical outcome of patients with acute heart failure (AHF).

Objective:

To evaluate the effect of lower doses of tezosentan in patients with AHF.

Subjects and methods:

Included were 130 patients hospitalized due to AHF with dyspnea at rest, despite initial treatment, and were in need of hemodynamic monitoring with cardiac index (CI)<2.5 l/min/m2 and wedge pressure≥20 mm Hg. Patients were randomized in a double‐blind fashion to receive placebo or tezosentan: 0.2, 1, 5, or 25 mg/h for 24 h.

Results:

The primary endpoint of the study, CI increase at 6 h of treatment, was significant in the 5 and 25 mg/h groups. Tezosentan induced a dose‐dependent increase in CI and a decrease in wedge pressure, peaking after 3 h in the 5 and 25 mg/h groups. In the 1‐mg/h group, this effect was smaller during the first 6 h and increased gradually, becoming significant at 24 h and beyond treatment discontinuation. There was no hemodynamic effect in the 0.2 mg/h arm. Type‐B natriuretic peptide (BNP) decreased in the 1, 5, and 25 mg/h groups but not on placebo. Endothelin levels were significantly increased by the 5 and 25 mg/h groups but not in the lower (≤1 mg/h) tezosentan doses. Urine output decreased on the 25‐mg/h dose. There was a trend towards improvement in patients' subjective dyspnea score and worsening heart failure events, mainly in the 1 mg/h group.

Conclusions:

In patients admitted with AHF, tezosentan doses of 1–25 mg/h are efficacious in improving the hemodynamics and reducing BNP. Tezosentan doses beyond 1 mg/h increased plasma endothelin levels and reduced urine output, probably limiting their clinical efficacy, as compared to tezosentan 1 mg/h.
Ecosystem indicators derived from satellite remotely sensed oceanographic data for the North Pacific
Authors: Polovina Jeffrey J. , Howell Evan A.
Published: February 2005

Satellite remotely sensed oceanographic data provide reliable global ocean coverage of sea surface temperature, sea surface height, surface winds, and ocean colour, with relatively high spatial and temporal resolution. We illustrate approaches to use these data to construct indicators that describe aspects of ecosystem dynamics in the North Pacific. Specifically, altimetry data are used to construct regional indicators of the ocean vertical structure, ocean colour data to describe the temporal chlorophyll dynamics of the coastal zone, ocean colour, sea surface temperature, and altimetry data to develop indices of biologically important ocean features, and finally altimetry data to drive a larval transport model and develop an index of larval retention. Recent changes in the North Pacific based on these indices are discussed.
Ecosystem approach to fisheries: a review of implementation guidelines1
Authors: Garcia Serge M. , Cochrane Kevern L.
Published: February 2005

The FAO and other guidelines available for the implementation of the ecosystem approach to fisheries are briefly reviewed. The paper recalls the high-level policy foundations and the main issues, related to fisheries and non-fishing impacts as well as to natural variability. It reviews the central paradigm and the extension of the conventional management required to better account for ecosystem considerations. It focuses on the policy, strategy development, and implementation processes required to adapt the fuzzy principles and conceptual goals to the reality of specific situations, addressing briefly the central issues of capacity-building, management costs, realistic time frames, and the role of science, and concludes with comments on the respective roles of the various types of stakeholders.
Identification of an agent suitable for disinfecting boots of visitors to the Antarctic
Authors: Curry C.H. , McCarthy J.S. , Darragh H.M. , Wake R.A. , Churchill S.E. , Robins A.M. , Lowen R.J.
Published: February 2005

Studies of Antarctic fauna have led to tentative identification of a range of potential pathogens for both animals and humans. The rapid increase in visitors on tourist ships to the continent, now exceeding 10,000 per year, raises the concern that humans might transmit pathogens into and between wildlife colonies. The authors investigated the feasibility and efficacy of chemical disinfection of the microbial contamination on visitors' boots. During three voyages to penguin colonies in the Ross Sea, swabs were collected from the boots of visitors prior to landing, immediately on return to the ship, after a water wash, and after a chemical disinfectant wash using Virkon S. For the first two visits, abundant growth of bacteria was identified on boots at all three stages prior to disinfection. Following disinfection, the growth of bacteria was virtually eliminated. On the third visit, previously disinfected boots grew virtually no bacteria. After this landing the bacterial growth was substantially reduced by disinfection. These results indicate that consideration should be given to including disinfection in cleaning the boots of visitors to wildlife sites in the Antarctic to reduce the risk of translocation of microbial pathogens.
Formation of He2+ shell‐like distributions downstream of the Earth's bow shock
Authors: Lu Q. M. , Wang S.
Published: February 2005

When the incident solar wind He2+ and H+ distributions cross the electrostatic potential at the shock, they are decelerated differentially due to their different charge‐ to‐mass ratios. This differential slowing will produce a He2+ ring‐beam distribution immediately downstream from a quasi‐perpendicular shock. In this letter, we perform one‐dimensional (1D) hybrid simulations and investigate the evolution of the He2+ ring‐beam distribution in magnetized plasma. The plasma is composed of three components: H+, He2+ and electrons, where H+ has a velocity distribution with large perpendicular temperature anisotropy. It is shown that both the He2+ ring‐beam distribution and H+ distribution with large perpendicular temperature anisotropy can excite ion cyclotron waves with propagation direction parallel to the ambient magnetic field, and then the waves pitch‐angle scatter the He2+ ions. However, only the ion cyclotron waves excited by the He2+ ring‐beam distribution can transform He2+ into shell‐like distribution. The results can explain the He2+ shell‐like distributions downstream of the Earth's bow shock, which have already been observed with the AMPTE/CCE and ISEE spacecraft.
Potential for landsliding: Dependence on hyetograph characteristics
Authors: D'Odorico Paolo , Fagherazzi Sergio , Rigon Riccardo
Published: February 2005

This paper examines the effect of hyetograph shape on the potential for landsliding in soil‐mantled landscapes. An existing pore pressure response model (Iverson, 2000) is used to study the effects of unsteady rainfall infiltration in hillslopes, and the effect of slope and convergent topography is expressed using a steady state model of slope‐parallel subsurface flow. Slope stability is assessed using an infinite slope analysis. This theoretical framework is coupled with simple hyetograph models and to intensity‐duration‐frequency functions to determine the return period of landslide‐triggering rainfall. Results also show that hyetographs with a peak at the end of a rainfall event have a stronger destabilizing effect than hyetographs with a constant rainfall or with a peak at the beginning of a storm. Thus the variability of hyetograph shapes adds uncertainty to the assessment of landsliding triggered by rainfall.
Radial fractional‐order dispersion through fractured rock
Authors: Benson David A. , Tadjeran Charles , Meerschaert Mark M. , Farnham Irene , Pohll Greg
Published: February 2005

A solute transport equation with a fractional‐order dispersion term is a model of solute movement in aquifers with very wide distributions of velocity. The equation is typically formulated in Cartesian coordinates with constant coefficients. In situations where wells may act as either sources or sinks in these models, a radial coordinate system provides a more natural framework for deriving the resulting differential equations and the associated initial and boundary conditions. We provide the fractional radial flow advection‐dispersion equation with nonconstant coefficients and develop a stable numerical solution using finite differences. The hallmark of a spatially fractional‐order dispersion term is the rapid transport of the leading edge of a plume compared to the classical Fickian model. The numerical solution of the fractional radial transport equation is able to reproduce the early breakthrough of bromide observed in a radial tracer test conducted in a fractured granite aquifer. The early breakthrough of bromide is underpredicted by the classical radial transport model. Another conservative, yet nonnaturally occurring solute (pentaflourobenzoate), also shows early breakthrough but does not conclusively support the bromide model due to poor detection at very low concentrations. The solution method includes, through a procedure called subordination, the effects of solute partitioning on immobile water.
Chronic Graft–Versus–Host Disease of the Liver: Presentation As An Acute Hepatitis
Authors: Strasser Simone I. , Shulman Howard M. , Flowers Mary E. , Reddy Rajender , Margolis David A. , Prumbaum Manfred , Seropian Stuart E. , McDonald George B.
Published: February 2005

Chronic graft–versus–host disease (GVHD) of the liver usually presents as an indolent cholestatic disease in patients with skin, mouth, and eye involvement. We observed 14 patients in whom chronic GVHD of the liver presented with marked elevations of serum aminotransferases, clinically resembling acute viral hepatitis. Onset of liver dysfunction was at 294 days (range, 74–747 days) after allogeneic hematopoietic cell transplantation and coincided with a recent cessation or taper of immunosuppressive drugs. Median peak serum alanine transaminase (ALT) was 1,640 U/L (698–2,565 U/L), and median bilirubin was 12.3 mg/dL (0.9–55.9 mg/dL). All biopsies showed characteristic features of GVHD with damaged and degenerative small bile ducts. Other features included a marked lobular hepatitis, moderate to marked amounts of hepatocyte unrest, sinusoidal inflammation with perivenular necroinflammatory foci, and many acidophilic bodies scattered throughout the lobule. When high–dose immunosuppressive therapy was instituted soon after presentation, progressive improvement and eventual normalization of liver enzymes and bilirubin levels were observed. However, in cases in which the diagnosis was not made and therapy was delayed, a progressive cholestatic picture emerged with histologic evidence of loss of small bile ducts and portal fibrosis. We conclude that a distinct syndrome of chronic liver GVHD presenting as an acute hepatitis can be recognized in a patient at risk who is receiving no, or minimal, immunosuppressive medications. Liver biopsy is necessary to exclude viral causes of liver dysfunction and to confirm characteristic abnormalities of small bile ducts. Institution of high–dose immunosuppression can prevent progressive bile duct destruction and effect resolution of jaundice if given early.
Fibrous Obliterative Lesions of Veins Contribute to Progressive Fibrosis in Chronic Liver Allograft Rejection
Authors: Nakazawa Yuichi , Jonsson Julie R. , Walker Neal I. , Kerlin Paul , Steadman Charles , Lynch Stephen V. , Strong Russell W. , Clouston Andrew D.
Published: February 2005

Fibrosis in liver allografts undergoing chronic rejection (CR) is variable and poorly understood. The temporal and spatial relationships of venous, arterial, and biliary lesions were studied to clarify their potential contributions to graft fibrosis. The severity, prevalence, and morphology of intimal lesions of vessels were analyzed and compared with the fibrosis stage. Three groups were found; group 1 (n = 5) with no hepatic vein (HV) lesions, group 2 (n = 5) with HV lesions only, and group 3 with lesions of both HV and portal veins (PV). The earliest lesion to develop, in 71% of grafts, was concentric intimal thickening of small HV. This was significantly more severe and frequent in grafts from group 3. With increasing frequency and severity of small HV sclerosis, fibrosis developed in medium/large veins. The morphology of larger vessel lesions suggested organized thrombus. Centrilobular fibrosis was significantly more severe in group 3 and developed unpredictably and sometimes rapidly. Conversely, portal fibrosis scores were significantly higher in grafts with ductular proliferation and did not correlate with venous lesions. This suggests that in CR, veno–occlusive–like lesions develop commonly in terminal hepatic venules, probably caused by immune–mediated damage. In only a proportion, with increased frequency and severity of the lesions, stasis and thrombosis in portal and larger veins occur and could result in loss of hepatic and portal venous outflow, which leads to ischemia and fibrosis. The stage of fibrosis did not correlate with foam–cell arteriopathy. A second pathway of portal fibrosis occurs in patients with longstanding biliary proliferation.
The shear viscosity of supercritical oxygen at high pressure
Authors: Abramson E. H.
Published: February 2005

Shear viscosities of supercritical oxygen have been measured up to a pressure of 5.7GPa at 294K. A modified free-volume expression fits the data within 6% between the limits of the tenuous gas and 4.8 times the critical density. Nitrogen viscosities were found to correspond to those of oxygen through a simple scaling by critical constants. Viscosities were measured in the high-pressure diamond-anvil cell with a rolling-ball technique. The dynamics of a sphere rolling on an inclined plane were investigated in the context of these experiments. The effect of a second surface, situated above the sphere, was experimentally determined.
Landing of size-selected Agn+ clusters on single crystal TiO2 (110)-(1×1) surfaces at room temperature
Authors: Benz Lauren , Tong Xiao , Kemper Paul , Lilach Yigal , Kolmakov Andrei , Metiu Horia , Bowers Michael T. , Buratto Steven K.
Published: February 2005

Mass-selected Agn+ (n=1,2,3) clusters with impact energy less than 2eV per atom were deposited from the gas phase onto rutile titania (110)-(1×1) single crystal surfaces at room temperature and imaged using ultra-high vacuum scanning tunneling microscopy. Upon reaching the surface, Ag monomers sintered to form three-dimensional islands of approximately 50 atoms in size, with an average measured height of 7.5Å and diameter of 42Å. This suggests that the monomers are highly mobile on the titania surface at room temperature. Dimers also sintered to form large clusters upon deposition, approximately 30 atoms in size, with an average height of 6.2Å and diameter of 33Å. Clusters formed from monomer deposition appeared approximately three times more frequently at step edges than clusters formed from dimer deposition, indicating that the surface mobility of deposited monomers is higher than that of deposited dimers. In sharp contrast to the deposition of monomers and dimers, the deposition of trimers resulted in a high density of very small clusters on the order of a few atoms in size, indicative of intact trimers on the surface, implying that deposited trimers have very limited mobility on the surface at room temperature.
Magnetization losses in multifilament coated superconductors
Authors: Levin G. A. , Barnes P. N. , Amemiya N. , Kasai S. , Yoda K. , Jiang Z.
Published: February 2005

We report the results of a study of the magnetization losses in experimental multifilament, as well as control (uniform) coated superconductors exposed to time-varying magnetic fields of various frequencies. Both the hysteresis loss, proportional to the sweep rate of the applied magnetic field, and the coupling loss, proportional to the square of the sweep rate, have been observed. A scaling is found that allows us to quantify each of these contributions and extrapolate the results of the experiment beyond the envelope of accessible field amplitude and frequency. The combined loss in the multifilament conductor is reduced by about 90% in comparison with the uniform conductor at full field penetration at a sweep rate as high as 3 T/s.
Comparison of the optical gain of InGaAsN quantum-well lasers with GaAs or GaAsP barriers
Authors: Carrère H. , Marie X. , Barrau J. , Amand T.
Published: February 2005

We have compared the calculated band structure and optical gain of compressively strained InGaAsN quantum-well lasers emitting at 1.3μm with GaAs or GaAsP barriers. The GaAsP barriers yield a better hole confinement in the quantum well due to GaAsP larger band gap. We show that this can result in an increase of the material gain of more than 40% at device operating temperature, which can be explained by the reduction of the hole leakage out of the quantum well.
Design and holographic fabrication of tetragonal and cubic photonic crystals with phase mask: toward the mass-production of three-dimensional photonic crystals
Authors: Lin Y. , Herman P. R. , Darmawikarta K.
Published: February 2005

We present design and holographic fabrication of the woodpile-type photonic crystals through phase mask techniques. Three-dimensional photonic crystal structures with tetragonal or cubic symmetries are fabricable by exposing the photoresist to the interference patterns generated by the phase masks. These photonic crystals have full photonic band gaps as large as 27% of the gap center frequency if made from silicon. The realized photonic crystal in SU-8 photoresist shows overlapped thus more stable woodpile-type structures. The phase-mask based lithography for the fabrication of the photonic crystals, together with the computer-controlled fabrication process, could take advantage of the standard tools of the electronics industry, leading toward the mass-production of the three-dimensional photonic crystals.
Crystallinity of Li-doped Gd2O3:Eu3+ thin-film phosphors grown on Si (100) substrate
Authors: Yi Soung Soo , Bae Jong Seong , Moon Byung Kee , Jeong Jung Hyun , Kim Jung Hwan
Published: February 2005

Gd 2 O 3 : Eu 3 + and Li-doped Gd2O3:Eu3+ luminescent thin films have been grown on Si (100) substrates using pulsed-laser deposition. The films grown at different deposition conditions show different microstructural and luminescent characteristics. Both cubic and monoclinic crystalline structures were observed in both Gd2O3:Eu3+ and Li-doped Gd2O3:Eu3+ films, but the cubic phase becomes more dominant and the ratio of peak values IC(222)∕IM(−402) increases rapidly for Li-doped Gd2O3:Eu3+ films. The photoluminescence brightness data obtained from Li-doped Gd2O3:Eu3+ films indicate that Si (100) is a promising substrate for growth of high-quality Li-doped Gd2O3:Eu3+ thin-film red phosphor. In particular, the incorporation of Li+ ions into the Gd2O3 lattice induced changes of crystallinity, surface roughness, and photoluminescence. The highest emission intensity was observed with Gd1.84Li0.08Eu0.08O3, whose brightness was a factor of 2.1 larger than that from Gd2O3:Eu3+ films. This phosphor is promising for applications in flat-panel displays.
Location Coding by the Human Visual System: Multiple Topological Adaptations in a Case of Strabismic Amblyopia
Authors: Popple Ariella V , Levi Dennis M
Published: February 2005

Amblyopia, a major cause of vision loss, is a developmental disorder of visual perception commonly associated with strabismus (squint). Although defined by a reduction in visual acuity, severe distortions of perceived visual location are common in strabismic amblyopia. These distortions can help us understand the cortical coding of visual location and its development in normal vision, as well as in amblyopia. The history of retinotopic mapping in the visual cortex highlights the potential impact of amblyopia. Theories of amblyopia include topological disarray of receptors in primary visual cortex, undersampling from the amblyopic eye compared with normal eyes, and the presence of anomalous retinal correspondence or multiple cortical representations of the strabismic fovea. We examined the distortions in a strabismic amblyope, using a pop-out localization task, in which normal observers made errors dependent on the visual context of the stimulus. The localization errors of the strabismic amblyope were abnormal. We found that none of the available theories could fully explain this one patient's localization performance. Instead, the observed behavior suggests that multiple adaptations of the underlying cortical topology are possible simultaneously in different parts of the visual field.
Dissecting the PhoP regulatory network of
Escherichia coli
and
Salmonella enterica
Authors: Zwir Igor , Shin Dongwoo , Kato Akinori , Nishino Kunihiko , Latifi Tammy , Solomon Felix , Hare Janelle M. , Huang Henry , Groisman Eduardo A.
Published: February 2005

Genetic and genomic approaches have been successfully used to assign genes to distinct regulatory networks. However, the present challenge of distinguishing differentially regulated genes within a network is particularly hard because members of a given network tend to have similar regulatory features. We have addressed this challenge by developing a method, termed Gene Promoter Scan, that discriminates coregulated promoters by simultaneously considering both multiple
cis
promoter features and gene expression. Here, we apply this method to probe the regulatory networks governed by the PhoP/PhoQ two-component system in the enteric bacteria
Escherichia coli
and
Salmonella enterica
. Our analysis uncovered members of the PhoP regulon and interactions with other regulatory systems that were not discovered in previous approaches. The predictions made by Gene Promoter Scan were experimentally validated to establish that the PhoP protein uses multiple mechanisms to control gene transcription, regulates acid resistance determinants, and is a central element in a highly connected network.
Iron availability of a fortified processed wheat cereal: a comparison of fourteen iron forms using an in vitro digestion/human colonic adenocarcinoma (CaCo-2) cell model
Authors: Wortley Gary , Leusner Steven , Good Carolyn , Gugger Eric , Glahn Raymond
Published: February 2005

In this three-phase study we first compared the availability of fourteen Fe forms in a wheat-based ready-to-eat breakfast cereal using an in vitro digestion/human colonic adenocarcinoma (CaCo-2) cell model. We then investigated the effect of milk and/or coffee on those fortified cereals found in phase 1 to show promising increases in Fe availability. The Fe forms assessed in phase 1 were reduced (control), carbonyl, electrolytic, FePO4, FeSO4, FeCO3, Na2FeEDTA, Ferrochel® (Albion Laboratories, Clearfield, UT, USA; ferrous bis-glycinate), encapsulated ferrous fumarate, FeSO4, ferrous lactate and Biofer® (LipoTech, Britwell Salome, Oxfordshire; FeSO4), SQM® (Sea-Questra-Min Iron; Quali Tech, Chaska, MN, USA; polysaccharide-complexed FeSO4) and Sun Active® (Taiyo Kagaku, Yokkaichi, Japan). All these forms increased Fe uptake compared with the unfortified cereal. Relative to the control, the following increases in Fe availability were observed: electrolytic, 52 %; ferrous fumarate, 30–35 %; Sun Active, 78 %; Ferrochel, 125 %; Na2FeEDTA, 291 %. Recent human studies have shown similar data with regard to Ferrochel, FeSO4 and Na2FeEDTA, with the latter being more bioavailable. Our phase-2 studies indicated that the addition of milk to FeSO4-fortified cereal increased Fe availability, but this availability was markedly decreased by the addition of coffee to the digest. Conversely, a loss in availability from Na2FeEDTA was observed with the addition of milk; however, the addition of coffee did not markedly affect Fe availability from this form. In phase-3 studies we observed increased Fe availability upon the addition of milk to cereals containing Ferrochel, FeSO4, Sun Active, a mixture of reduced Fe and Na2FeEDTA or reduced Fe. For these forms we did not assess the behaviour after the addition of coffee. In conclusion, when considering possible fortificants for optimizing Fe bioavailability within a foodstuff, it is of paramount importance to consider the interaction between the fortified foodstuffs and other components of the meal (such as milk and coffee with a breakfast).