bluuebunny/crossref_metadata_2025 huggingface dataset:
Microsatellite analysis of the adenomatous polyposis coli (APC) gene and immunoexpression of β catenin in nephroblastoma: a study including 83 cases treated with preoperative chemotherapy
Authors: Ramburan A , Oladiran F , Smith C , Hadley G P , Govender D
Published: December 2004

Aims:To determine whether microsatellite mutations of the adenomatous polyposis coli (APC) gene have pathological or prognostic significance in nephroblastomas and to correlate APC alterations with β catenin immunoexpression.

Methods:One hundred nephroblastomas were analysed, 83 of which received preoperative chemotherapy. Normal and tumour DNA was isolated using standard proteinase K digestion and phenol/chloroform extraction from paraffin wax embedded tissue. Polymerase chain reaction using four APC microsatellite markers—D5S210, D5S299, D5S82, and D5S346—was performed and the products analysed. Immunohistochemistry was performed using the LSAB kit with diaminobenzidine as chromogen. Results were correlated with clinicopathological data using the χ2test.

Results:Allelic imbalance/loss of heterozygosity was more frequent than microsatellite instability, with 30% of cases showing allelic imbalance/ loss of heterozygosity and 16% showing microsatellite instability. Although there was a significant correlation between the results for individual markers and the clinicopathological data, the overall results do not support a prognostic role for APC in nephroblastoma. Expression of β catenin was seen in 93% of cases. Staining was predominantly membranous, with epithelium, blastema, and stroma being immunoreactive. Cytoplasmic redistribution was seen in 58% of cases, but no nuclear staining was detected. No significant associations between β catenin expression and the clinicopathological parameters were found. Kaplan–Meier survival plots showed that patients with loss of membranous staining and pronounced cytoplasmic staining (score, 3) had a significantly shorter survival (p = 0.04; median survival, 5.87 months).

Conclusion:Microsatellite analysis of APC and immunoexpression of β catenin did not provide significant pathological or prognostic information in this cohort of nephroblastomas.
Antimicrobial activity of UMFix tissue fixative
Authors: Cleary T J , Morales A R , Nadji M , Nassiri M , Vincek V
Published: December 2004

Aims:The aim of this study was to determine the antimicrobial effects of UMFix, an alcohol based tissue fixative, on various microorganisms. The UMFix solution was compared with 10% neutral buffered formalin.

Methods:Standard methods to determine microorganism colony counts were performed after exposure of the microorganisms to UMFix and 10% neutral buffered formalin.

Results:After a short exposure, UMFix rapidly killed vegetative bacteria, yeasts, moulds, and viruses. Bacterial spores were resistant to killing by UMFix. All organisms were killed by the 10% neutral buffered formalin preparation.

Conclusions:UMFix was microbicidal for vegetative bacteria, yeasts, and aspergillus species after a short exposure, although it was not active against spore forming bacillus species. The methanol content of the fixative was responsible for the killing effect of this fixative. No killing was seen when polyethylene glycol was used alone.
PARALLIZING 1-DIMENSIONAL ESTUARINE MODEL
Authors: LUO JUN , RAJASEKARAN SANGUTHEVAR
Published: December 2004

Wave simulation is an important problem in engineering. Wave simulation models play significant roles in environmental protection. Wave simulations have thus far been done mostly serially. In order to meet the demand for increased spatial and temporal resolution and uncertainty analysis in environmental models for ecological assessments and water resource managements, it is essential to develop high-performance hydrodynamics and water quality models using parallel techniques. In this paper, algorithms for parallelizing 1-D wave simulation models are proposed. In particular, we introduce a paradigm called Less Talk for reducing communication costs in parallel computing. Our wave models have been implemented using Parallel Virtual Machine (PVM) and Multithreading. The experiments show that these algorithms that employ Less Talk are efficient and the parallel wave simulation models have excellent speedup performances.
WHITEHEAD EXACT SEQUENCE AND DIFFERENTIAL GRADED FREE LIE ALGEBRA
Authors: BENKHALIFA MAHMOUD
Published: December 2004

Let R be a principal and integral domain. We say that two differential graded free Lie algebras over R (free dgl for short) are weakly equivalent if and only if the homologies of their corresponding enveloping universal algebras are isomophic. This paper is devoted to the problem of how we can characterize the weakly equivalent class of a free dgl. Our tool to address this question is the Whitehead exact sequence. We show, under a certain condition, that two R-free dgls are weakly equivalent if and only if their Whitehead sequences are isomorphic.
PROBING THE LIGHT SPEED ANISOTROPY WITH RESPECT TO THE COSMIC MICROWAVE BACKGROUND RADIATION DIPOLE
Authors: GURZADYAN V. G. , BOCQUET J.-P. , KASHIN A. , MARGARIAN A. , BARTALINI O. , BELLINI V. , CASTOLDI M. , D'ANGELO A. , DIDELEZ J.-P. , DI SALVO R. , FANTINI A. , GERVINO G. , GHIO F. , GIROLAMI B. , GIUSA A. , GUIDAL M. , HOURANY E. , KNYAZYAN S. , KOUZNETSOV V. , KUNNE R. , LAPIK A. , LEVI SANDRI P. , LLERES A. , MEHRABYAN S. , MORICCIANI D. , NEDOREZOV V. , PERRIN C. , REBREYEND D. , RUSSO G. , RUDNEV N. , SCHAERF C. , SPERDUTO M.-L. , SUTERA M.-C. , TURINGE A.
Published: December 2004

We have studied the angular fluctuations in the speed of light with respect to the apex of the dipole of Cosmic Microwave Background (CMB) radiation using the experimental data obtained with GRAAL facility, located at the European Synchrotron Radiation Facility (ESRF) in Grenoble. The measurements were based on the stability of the Compton edge of laser photons scattered on the 6 GeV monochromatic electron beam. The results enable one to obtain a conservative constraint on the anisotropy in the light speed variations Δc(θ)/c<3×10-12, i.e. with higher precision than from previous experiments.
ON THE NONLINEAR STABILITY OF MARANGONI–BÉNARD PROBLEM WITH FREE SURFACE IN THE BOUSSINESQ APPROXIMATION
Authors: GUIDOBONI GIOVANNA , JIN BUM JA
Published: December 2004

We study the Bénard problem in the Boussinesq approximation with upper free surface in the presence of surface tension. Both buoyancy and Marangoni effect are taken into account. Defining a suitable energy functional, we obtain sufficient conditions for nonlinear exponential stability of the rest state.
CONTINUOUS DEPENDENCE ON DATA FOR VIBRO-IMPACT PROBLEMS
Authors: PAOLI LAETITIA
Published: December 2004

We consider vibro-impact problems, i.e. mechanical systems with a finite number of degrees of freedom subject to frictionless unilateral constraints. The dynamics is described by a second-order measure differential inclusion completed by an impact law of Newton's type. Motivated by the computation of approximate solutions, we study in this paper the continuous dependence of solutions on data. When several constraints can be active at the same time, continuity on data does not hold in general and an example of such a behavior is presented. We then propose a criterion involving the geometry of the active constraints along the limit trajectory which ensures continuity on data.
ANALYSIS OF A MATHEMATICAL MODEL OF TUMOR LYMPHANGIOGENESIS
Authors: FRIEDMAN AVNER , LOLAS GEORGIOS
Published: December 2004

Tumor survival, growth and dissemination are associated with the formation of both new blood vessels (angiogenesis) and new lymph vessels (lymphangiogenesis). A mathematical model of tumor lymphangiogenesis was recently developed by the authors, based on experimental results established in the last five years. The model consists of a coupled system of eight parabolic equations. In this paper we prove existence and uniqueness of a solution for this system, for all t>0.
FEATURE SELECTION FOR SUPPORT VECTOR MACHINES USING GENETIC ALGORITHMS
Authors: FRÖHLICH HOLGER , CHAPELLE OLIVIER , SCHÖLKOPF BERNHARD
Published: December 2004

The problem of feature selection is a difficult combinatorial task in Machine Learning and of high practical relevance, e.g. in bioinformatics. Genetic Algorithms (GAs) offer a natural way to solve this problem. In this paper we present a special Genetic Algorithm, which especially takes into account the existing bounds on the generalization error for Support Vector Machines (SVMs). This new approach is compared to the traditional method of performing cross-validation and to other existing algorithms for feature selection.
GLOBAL RULE INDUCTION FOR INFORMATION EXTRACTION
Authors: XIAO JING , CHUA TAT-SENG , LIU JIMIN
Published: December 2004

The ability to extract desired pieces of information from natural language texts is an important task with a growing number of potential applications. This paper presents a novel pattern rule induction learning system, GRID, which emphasizes the use of global feature distribution in all of the training instances in order to make better decision on rule induction. GRID uses chunks as contextual units instead of tokens, and incorporates features at lexical, syntactical and semantic levels simultaneously. The features chosen in GRID are general and they were applied successfully to both semi-structured text and free text. Our experimental results on some publicly available webpage corpora and MUC-4 test set indicate that our approach is effective.
A SOFTWARE INFRASTRUCTURE FOR RESEARCH IN TEXTUAL DATA MINING
Authors: HOLZMAN LARS E. , FISHER TODD A. , GALITSKY LEON M. , KONTOSTATHIS APRIL , POTTENGER WILLIAM M.
Published: December 2004

Few tools exist that address the challenges facing researchers in the Textual Data Mining (TDM) field. Some are too specific to their application, or are prototypes not suitable for general use. More general tools often are not capable of processing large volumes of data. We have created a Textual Data Mining Infrastructure (TMI) that incorporates both existing and new capabilities in a reusable framework conducive to developing new tools and components. TMI adheres to strict guidelines that allow it to run in a wide range of processing environments – as a result, it accommodates the volume of computing and diversity of research occurring in TDM. A unique capability of TMI is support for optimization. This facilitates text mining research by automating the search for optimal parameters in text mining algorithms. In this article we describe a number of applications that use the TMI. A brief tutorial is provided on the use of TMI. We present several novel results that have not been published elsewhere. We also discuss how the TMI utilizes existing machine-learning libraries, thereby enabling researchers to continue and extend their endeavors with minimal effort. Towards that end, TMI is available on the web at .
ACTIVE LEZI: AN INCREMENTAL PARSING ALGORITHM FOR SEQUENTIAL PREDICTION
Authors: GOPALRATNAM KARTHIK , COOK DIANE J.
Published: December 2004

Prediction is an important component in a variety of domains in Artificial Intelligence and Machine Learning, in order that Intelligent Systems may make more informed and reliable decisions. Certain domains require that prediction be performed on sequences of events that can typically be modeled as stochastic processes. This work presents Active LeZi (ALZ), a sequential prediction algorithm that is founded on an Information Theoretic approach, and is based on the acclaimed LZ78 family of data compression algorithms. The efficacy of this algorithm in a typical Smart Environment – the Smart Home, is demonstrated by employing this algorithm to predict device usage in the home. The performance of this algorithm is tested on synthetic data sets that are representative of typical interactions between a Smart Home and the inhabitant. In addition, for the Smart Home environment, we introduce a method of learning a measure of the relative time between actions using ALZ, and demonstrate the efficacy of this approach on synthetic Smart Home data.
HOFER–ZEHNDER CAPACITY AND HAMILTONIAN CIRCLE ACTIONS
Authors: MACARINI LEONARDO
Published: December 2004

We introduce the Hofer–Zehnder Γ-semicapacity [Formula: see text] of a symplectic manifold (M,ω) (or Γ-sensitive Hofer–Zehnder capacity) with respect to a subset Γ⊂π1(M)[Formula: see text] and prove that given a geometrically bounded symplectic manifold (M,ω) and an open subset N⊂M admitting a Hamiltonian free circle action with order greater than two then N has bounded Hofer–Zehnder Γ-semicapacity, where Γ⊂π1(N) is the subgroup generated by the orbits of the action.

We give several applications of this result. Using Biran's decomposition theorem, we prove the following: let (M2n,Ω) be a closed Kähler manifold (n>2) with [Ω]∈H2(M,ℤ) and Σ a complex hypersurface representing the Poincaré dual of k[Ω], for some k∈ℕ. Suppose either that Ω vanishes on π2(M) or that k>2. Then there exists a decomposition of M into an open dense subset E such that E\Σ has finite Hofer–Zehnder Γ-semicapacity and an isotropic CW-complex, where Γ⊂π1(E\Σ) is the subgroup generated by the obvious circle action on the normal bundle of Σ. Moreover, we prove that if (M,Σ) is subcritical then M\Σ has finite Hofer–Zehnder Γ-semicapacity.

We also show that given a hyperbolic surface M and TM endowed with the twisted symplectic form ω0+π*Ω, where Ω is the Kähler form on M, then the Hofer–Zehnder Γ-semicapacity of the domain Uk bounded by the hypersurface of kinetic energy k minus the zero section M0 is finite if k<1/2, where Γ⊂π1(Uk) is the subgroup generated by the fibers of SM.

Finally, we consider the problem of the existence of periodic orbits on prescribed energy levels for magnetic flows. We prove that given any weakly exact magnetic field Ω on any compact Riemannian manifold M there exists a sequence of contractible periodic orbits of arbitrarily small energy, extending a previous result of Polterovich.
SOME EXISTENCE AND NONEXISTENCE RESULTS OF ISOMETRIC IMMERSIONS OF RIEMANNIAN MANIFOLDS
Authors: TANG ZIZHOU
Published: December 2004

This paper investigates existence and non-existence of immersions of Riemannian manifolds. It discovers the lowest dimension of the Euclidean space into which the projective plane FP2 is isometrically immersed, by the computation of the normal Euler class. For strictly hyperbolic immersion, a new obstruction involving signature or Kervaire semi-characteristic is found. As for the existence, it constructs a strictly hyperbolic immersion from the Klein bottle to the unit sphere S3(1), solving a question posed by Gromov.
APPROXIMATE SHOCK CURVES FOR NON-CONSERVATIVE HYPERBOLIC SYSTEMS IN ONE SPACE DIMENSION
Authors: ALOUGES FRANÇOIS , MERLET BENOIT
Published: December 2004

For non-conservative hyperbolic systems several definitions of shock waves have been introduced in the literature. In this paper, we propose a new and simple definition in the case of genuinely nonlinear fields. Relying on a vanishing viscosity process we prove the existence of shock curves for viscosity matrix commuting with the matrix of the hyperbolic system. This setting generalizes a recent result by Bianchini and Bressan. Furthermore we prove that all definitions agree to third order near a given state.
Periodic solutions for nonautonomous differential equations and inclusions in tubes
Authors: Gabor Grzegorz
Published: December 2004

We study the existence of periodic trajectories for nonautonomous differential equations and inclusions remaining in a prescribed compact subset of an extended phase space. These sets of constraints are nonconvex right‐continuous tubes not satisfying the viability tangential condition on the whole boundary. We find sufficient conditions for existence of viable periodic trajectories studying properties of the exit subset of the tube. A new approximation approach for continuous multivalued maps is presented.
Existence of solutions for elliptic equations having natural growth terms in Orlicz spaces
Authors: Elmahi A. , Meskine D.
Published: December 2004

Existence result for strongly nonlinear elliptic equation with a
natural growth condition on the nonlinearity is proved.
Multiple positive solutions for quasilinear elliptic problems with sign‐changing nonlinearities
Authors: Bonder Julián Fernández
Published: December 2004

Using variational arguments, we prove some nonexistence and multiplicity results for positive solutions of a system of p‐Laplace equations of gradient form. Then we study a p‐Laplace‐type problem with nonlinear boundary conditions.
An inverse problem for a second‐order differential equation in a Banach space
Authors: Eidelman Y.
Published: December 2004

We consider the problem of determining the unknown term in the right‐hand side of a second‐order differential equation with unbounded operator generating a cosine operator function from the overspecified boundary data. We obtain necessary and sufficient
conditions of the unique solvability of this problem in terms of location of the spectrum of the unbounded operator and properties of its resolvent.
Symmetry and concentration behavior of ground state in axially symmetric domains
Authors: Wu Tsung-Fang
Published: December 2004

We let Ω(r) be the axially symmetric bounded domains which satisfy some suitable conditions, then the ground‐state solutions of the semilinear elliptic equation in Ω(r) are nonaxially symmetric and concentrative on one side. Furthermore, we prove the
necessary and sufficient condition for the symmetry of ground‐state solutions.
An Analysis of Stream Habitat Conditions in Reference and Managed Watersheds on Some Federal Lands within the Columbia River Basin
Authors: Kershner Jeffrey L. , Roper Brett B. , Bouwes Nicolaas , Henderson Richard , Archer Eric
Published: December 2004

The loss of both habitat quality and quantity for anadromous fish in the Columbia River basin has been identified as a major factor in the decline of many species and has been linked to a variety of land management activities. In this study, we compared stream reaches in watersheds representing both managed and reference conditions to determine whether we could detect differences in physical habitat variables. We divided stream habitat measures into three components: Stream banks, instream habitat (pools and pool depth), and stream substrate. We randomly sampled perennial streams within 261 sixth hydrologic unit code (HUC) stream reaches on federal lands in Idaho, Montana, Oregon, and Washington. The sample population represented stream reaches in 62 reference watersheds and 199 managed watersheds. An unbalanced, incomplete-block-design analysis of covariance (ANCOVA) was performed on each of the habitat variables using geology type as the block effect and bank-full width, stream gradient, and average precipitation as the covariates. Watersheds containing reference stream reaches had a slightly higher percentage of federal lands, were smaller, tended to occur at higher mean elevations, and received more annual precipitation than did the managed watersheds. We observed differences in most measures of stream habitat between reference and managed watersheds, generally in the direction we expected. Stream banks were more stable and more undercut in reference stream reaches. Pools in reference stream reaches were deeper than pools in managed stream reaches and had less fine sediment in pool tails. Analysis of covariance was an effective way to compare data across a large, relatively heterogeneous landscape where sample site stratification may be impractical or sample sizes are limited. We believe that the comparison of reference conditions to conditions across managed landscapes provides a credible way to report on the condition of these systems in lieu of trend information at individual sites.
Summer Movements within the Fish Community of a Small Montane Stream
Authors: Schmetterling David A. , Adams Susan B.
Published: December 2004

We studied movements by fishes in Chamberlain Creek, Montana, from 24 July to 16 August 2001. We operated six weirs with two-way traps and one additional upstream trap, separated by 14–1,596 m, to quantify the timing, direction, and distance of movements and to estimate fish populations in the study reaches. We trapped and marked 567 fish of seven species, including 368 westslope cutthroat trout Oncorhynchus clarkii lewisi and 172 sculpin (slimy sculpin Cottus cognatus and an unidentified species similar to mottled sculpin C. bairdii). We recaptured 173 westslope cutthroat trout and detected net movements as long as 1,581 m (median, 91 m). Bidirectional movements for 116 westslope cutthroat trout ranged from less than 18 to more than 1,581 m (median, 64 m). Sculpin moved as far as 209 m (median, 26 m). We estimate that 14% of sculpin and 48% of westslope cutthroat trout were mobile during the study. We captured all species more frequently at night or twilight (n = 296) than during the day (n = 83) and more frequently moving downstream (n = 419) than upstream (n = 277). These results demonstrate considerable summer movement by the fish community in a small stream.
Methodological Bias in Estimates of Strain Composition and Straying of Hatchery-Produced Steelhead in Lake Michigan Tributaries
Authors: Bartron Meredith L. , Swank Dave R. , Rutherford Edward S. , Scribner Kim T.
Published: December 2004

Steelhead Oncorhynchus mykiss were first introduced into the Great Lakes in the late 1800s. Subsequently, natural recruitment of steelhead from spawning runs in streams across the basin has been regularly supplemented by hatchery production of strains derived from widely dispersed locales within the species' native range. Estimates of hatchery contributions to the spawning runs of naturalized populations may be underrepresented by observations of marked fish, as not all hatchery fish are marked prior to release. To assess the potential bias in estimates of the hatchery contribution to steelhead spawning runs in four major rivers in Michigan, we used scale pattern analysis (SPA) to identify nonmarked hatchery fish and multilocus genotypes to estimate the proportional contributions of each hatchery strain to spawning runs. The four hatchery strains currently stocked are significantly genetically distinct (mean FST = 0.077), making it possible to identify specific strains by use of likelihood-based assignment tests. The differences between direct (mark observations) and indirect (SPA and genetic analysis) estimates of hatchery contribution were mainly due to variations in the percentage of hatchery fish marked by states prior to release and the potential for confusion between certain marks and injuries. By combining direct and indirect assessment methodologies, we estimated that the percentage of hatchery fish returning to the four rivers ranged from 13% to 31% of total spawning runs. The large contribution of hatchery fish to nonstocked rivers differed significantly from expectations of strain-specific stocking rates across the Lake Michigan basin and for individual streams, indicating high amounts of straying into Michigan streams.
Efficacy of a Chase Boat for Electrofishing Flathead Catfish in Three Oklahoma Reservoirs
Authors: Cunningham Kenneth K.
Published: December 2004

Electrofishing methods employed to sample flathead catfish Pylodictis olivaris in reservoirs can be labor-intensive when a chase boat is used to increase sampling efficiency. During summer 1997, I compared electrofishing results with and without a chase boat on three Oklahoma reservoirs. Capture efficiency, mean number of fish netted per 3-min sample, and length-frequency distribution were similar with and without a chase boat. I recommend discontinuing the use of a chase boat for sampling flathead catfish with electrofishing in reservoirs similar to those sampled in my study.
Fish Populations Associated with Habitat-Modified Piers and Natural Woody Debris in Piedmont Carolina Reservoirs
Authors: Barwick Robert D. , Kwak Thomas J. , Noble Richard L. , Barwick D. Hugh
Published: December 2004

A primary concern associated with reservoir shoreline residential development is reduction of littoral habitat complexity and diversity. One potential approach to compensate for this is the deployment of artificial-habitat modules under existing piers, but the benefit of this practice has not been demonstrated. To evaluate the effect of pier habitat modifications on fish populations in two Piedmont Carolina reservoirs, we studied 77 piers located on forty-seven, 100-m transects that were modified using plastic “fish hab” modules augmented with brush (brushed habs), hab modules alone (habs), or left unaltered for reference purposes. We sampled fish from all piers and transects during April, July, and October 2001 using a boat-mounted electrofisher. With few exceptions, catch rates were higher at brushed-hab piers and piers with habs than at reference piers during all seasons. Similarly, during spring and summer, fish abundance was generally higher on transects containing natural woody debris, brushed habs, and habs than on reference-developed transects; however, during fall, there were exceptions. Therefore, fish abundance associated with shorelines in these reservoirs appears to be related to the structural complexity of available habitat rather than structure composition. One year after installation, 92% of pier owners responding to a mail survey expressed satisfaction with pier modifications. Supplementing piers with habitat structures is recommended to enhance littoral habitat complexity for fishes in residentially developed reservoirs.
Evaluating Stream Habitat Survey Data and Statistical Power Using an Example from Southeast Alaska
Authors: Bryant Mason D. , Caouette John P. , Wright Brenda E.
Published: December 2004

Stream habitat surveys and watershed assessments have been developed and used as monitoring tools for decades. Most rely on type I error as the primary criterion, with minor consideration of statistical power and effect size. We test for statistical differences in fish habitat condition between harvested and nonharvested watersheds from habitat survey data collected in southeast Alaska. We apply statistical power analysis to judge whether nonsignificant results can be interpreted with confidence. None of the fish habitat variables we examined were significant at α = 0.05; however, several P-values were less than 0.10 and consistent differences between harvested and nonharvested reaches were observed among channel types. Statistical power is low and the probability of not detecting differences is high when the effect size, scaled to the standard deviation of the measurement, is small to medium. For large effect sizes, the ability to detect differences was greater but did not exceed 85% for any measurement. Statistical power, effect size, and biological significance of the outcome are important considerations when the results are interpreted and can lend additional information to managers making decisions with data that are less than perfect.
Ice Processes Affect Habitat Use and Movements of Adult Cutthroat Trout and Brook Trout in a Wyoming Foothills Stream
Authors: Lindstrom Jason W. , Hubert Wayne A.
Published: December 2004

Habitat use and movements of 25 adult cutthroat trout Oncorhynchus clarkii and 25 adult brook trout Salvelinus fontinalis from fall through winter 2002–2003 were assessed by means of radiotelemetry in a 7-km reach of a Rocky Mountains foothills stream. Temporal dynamics of winter habitat conditions were evaluated by regularly measuring the features of 30 pools and 5 beaver Castor canadensis ponds in the study reach. Groundwater inputs at three locations raised mean daily water temperatures in the stream channel during winter to 0.2–0.6°C and kept at least 250 m of the downstream channel free of ice, but the lack of surface ice further downstream led to the occurrence of frazil ice and anchor ice in pools and unstable habitat conditions for trout. Pools in segments that were not affected by groundwater inputs and beaver ponds tended to be stable and snow accumulated on the surface ice. Pools throughout the study reach tended to become more stable as snow accumulated. Both cutthroat trout and brook trout selected beaver ponds as winter progressed but tended to use lateral scour pools in proportion to their availability. Tagged fish not in beaver ponds selected lateral scour pools that were deeper than average and stable during winter. Movement frequencies by tagged fish decreased from fall through winter, but some individuals of both species moved during winter. Ice processes affected both the habitat use and movement patterns of cutthroat trout and brook trout in this foothills stream.
Generation of complex Metal Oxides by Aerosol Processes: Superconducting ceramic particles and films
Authors: Kodas Toivo T.
Published: December 2004

Complex metal oxides, including ferroelectric, ferrimagnetic and superconducting ceramics, have a variety of technologically useful properties that can be exploited for a number of applications. Fabrication of complex metal oxide ceramics with specific properties requires high‐purity powders with controlled chemical compositions, size distributions, and morphologies. Powders with these characteristics can be produced by aerosol processes in which fine particles are generated in gaseous flow systems. The particles can also be deposited from the gas phase onto surfaces to form films. This paper will discuss the use of aerosol processes for the generation of complex metal oxide powders. A review of aerosol processes will be presented first, followed by a discussion of the methods used for the generation of superconducting ceramic powders. Examples include the production of YBa2Cu3O7, La1.85Sr0.15CuO4, and Tl‐Ca‐Ba‐Cu‐O powders and films. Emphasis will be placed on defining the conditions required for the generation of chemically homogeneous particles with controlled morphologies.
Advanced Catalysts: Interfaces in the physical and biological sciences
Authors: Thomas John M.
Published: December 2004

The presidential addressto the chemistry section of the British Association for the Advancement of Science (BAAS) to be given in Sheffield in September by John Thomas (see picture) concentrates on the roles that catalysts play in chemical synthesis both in industry and in a biological environment. The future of catalysts rests in the hands of interdisciplinary scientists and engineers who, when faced with the problem of developing a new catalytic system, can call upon experience from such diverse fields as solid state physics and biology.

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Polymers with a high refractive index and low optical dispersion
Authors: Simmrock Hans‐U. , Mathy Alfred , Dominguez Ligia , Meyer Wolfgang H. , Wegner Gerhard
Published: December 2004

Organic Polyelectrolytes (I‐VII) known as Ionenes, with unique combinations of high refractive index (ND) and high Abbe number (VD, see figure) now compete with inorganic glasses for application in optics. Variation of the counterions allows the tuning of their chemical and optical properties.

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Imaging organic molecules with the scanning tunneling microscope
Authors: Rabe Jürgen P.
Published: December 2004

The lack of electrical conductivity and the constant molecular mobility of organic molecules have, in the past, restricted the successful imaging of these systems by STM. Recently, however, a number of new organic systems have been imaged. Jürgen Rabe reports on these new developments and in the future will write regularly for ADVANCED MATERIALS on surface analysis techniques especially scanning microscopy methods.
Joining ceramics, glass and metal in Bad Nauheim
Authors: Partridge Graham
Published: December 2004

G. Partridge (GEC) reports on a meeting which concerned the joining of ceramics, glass, and metals and E. Murinero and T. Suzuki (IBM) on two major symposia from the spring meeting of the MRS, on magnetic and magneto‐optic thin films and multilayers.
Sol‐gel technology for thin films, fibers, preforms, electronics and specialty shapes. Edited by L. C. Klein. Noyes Publications, New Jersey, USA 1988. xxi, 407 pp., bound, US$72.–1SBN 0‐8155‐1154‐X
Authors: Brook Richard
Published: December 2004

L. C. Klein (Ed.): Sol‐Gel Technology for Thin Films, Fibers, Preforms, Electronics and Speciality Shapes reviewed by R. Brook–M. Rosoff (Ed.): Controlled Release of Drugs: Polymers and Aggregated Systems reviewed by D. W. Grainger – R. M. Hazen: Superconductors: The Breakthrough reviewed by P. Gregory – C. B. McArdle (Ed.): Side Chain Liquid Crystal Polymers reviewed by H.‐W. Schmidt.
Designing Luminescent Materials
Authors: Bredol Michael , Kynast Ulrich , Ronda Cornelis
Published: December 2004

Review: Non‐conventional phosphor host materials such as cryptands (see Figure) or zeolites now offer potential alternatives to the traditional inorganic solid‐state materials which find applications in e.g. fluorescent lamps, T.V. sets, or X‐ray detectors. Recent efforts to further optimize conventional materials are reviewed and a forward look is taken at the new‐generation materials which could further extend the physical limits of luminescence.

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Intrinsic redox behavior of inert polymer layers filled with copper phthalocyanine pigment
Authors: Beck Fritz , Jansen Rolf
Published: December 2004

Communication: New, inexpensive, stable electrode materials which function on the principle of heterogeneous redox catalysis have been prepared from a mixture of copper phthalocyanine (CuPc) and polytetrafluoroethylene (PTFE) or acrylate/melamine baking varnish. The electrode materials can be simply ‘painted’ on to a substrate and exhibits a greater stability than vapor‐deposited layers. As all the materials are readily available applications as synthesis electrodes and in electrochromic displays can be envisaged.
Submicron‐powder starting materials for advanced ferrites
Authors: Noordermeer Arjan , Severin‐Vantilt Marijke M. E.
Published: December 2004

Research News: The dependence of the microstructure on the processing route and conditions has a profound effect on the performance of ferrites (magnetic oxides) in applications such as cores for transformers and inductors, and in video heads. Methods of optimizing the microstructures of the materials for particular applications are discussed with special emphasis on a consolidation method which is a combination of sedimentation and filtration.
Upconversion in fluoride glass fibers
Authors: Oomen Manuel
Published: December 2004

Research News: Compact visible (blue) lasers are required for applications such as barcode reading, laser printing, and high‐definition optical recording. An alternative method to frequency doubling to obtain blue laser light is the up‐conversion of infrared light. In this process photons are converted to higher energies by generating high‐energy excited states in the energy level scheme of a rare‐earth ion which then emit at a higher frequency than that of the infrared excitation source.
The discovery of hidden arsenic species in coastal waters
Authors: Howard A G , Comber S D W
Published: December 2004

The analysis of ultraviolet (UV)‐irradiated and untreated seawater samples has shown that the dissolved arsenic content of marine waters cannot be completely determined by hydride generation–atomic absorption spectrophotometry without sample pretreatment. Irradiation of water samples obtained during a survey of arsenic species in coastal waters during the summer of 1988 gave large increases in the measured speciation. Average increases in the measured speciation. Average increases in total arsenic, monomethylarsenic and dimethylarsenic were 0.29 μg As dm−3 (25%), 0.03 μg As dm−3 (47%) and 0.12 μg As dm−3 (79%), respectively. Overall, an average 25% increase in the concentration of dissolved arsenic was observed following irradiation.

This additional arsenic may be derived from compounds related to algal arsenosugars or to their breakdown products. These do not readily yield volatile hydrides when treated with borohydride and are not therefore detected by the normal hydride generation technique. This has important repercussions as for many years this procedure, and other analytical procedures which are equally unlikely to respond to such compounds, have been accepted as giving a true representation of the dissolved arsenic speciation in estuarine and coastal waters. A gross underestimate may therefore have been made of biological involvement in arsenic cycling in the aquatic environment.
Encapsulation of organotin compounds in metal acetate glasses
Authors: Duffy John A , Harston Paul , Wardell James L , Smith Peter J
Published: December 2004

Triorganotin halides, oxides and sulphides can be dissolved in molten, mixed‐metal acetates at ca 140–160°C without decomposition; quenching provides glasses into which are encapsulated the organotin species. Halide/acetate and oxide/acetate, but not sulphide/acetate, exchanges occur in the melt. Only partial exchange was found for hindered trineophyl tin chloride [(PhCMe2CH2)3SnCl], in contrast to the complete exchanges observed for the butyl (Bu), phenyl (Ph) and cyclohexyl (Cy) analogues. Complete oxide/acetate exchange was found for (Bu3Sn)2O, partial exchange occurred for (Cy3Sn)2O, whilst no exchange resulted with bis(trineophyltin) oxide or (Ph3Sn)2O. Tin–tin bonds (e.g. as in Ph3SnSnPh3) and carbon–tin bonds (even the allyl–Sn bond in Bu3SnCH2CHCH2) are not affected. The acetate glasses dissolve in aqueous media with release of the organotin species and they have potential as slow‐release systems which is currently being investigated.
Iron‐containing organometallic compounds as flame‐retarding/smoke‐suppressing additives for semi‐rigid poly(vinyl chloride)
Authors: Carty P , Adger B M
Published: December 2004

The incorporation of a range of iron‐containing organometallic compounds into a cable and wire poly(vinyl chloride) (PVC) formulation has been investigated. Limiting Oxygen Index and smoke density data were obtained across a range of formulations and the effects of the compounds on flammability and smoke generation are discussed. All the organoiron compounds markedly reduce smoke formation and some of them synergistically reduce the flammability of the polymer.
Iridium carbonyl clusters with pyridylphosphines: [Ir4(CO)9(PPhxpyl3−x)3]
Authors: Wajda‐Hermanowicz K , Koralewicz M , Pruchnik F P
Published: December 2004

[Ir4(CO)9(PR3)3] type complexes were obtained in the reaction between Ir4(CO)12 and the 2‐pyridylphosphines: diphenyl(2‐pyridyl)phosphine (PPh2pyl), phenylbis(2‐pyridyl)phosphine (PPhpyl2), tris‐(2‐pyridyl)phosphine (Ppyl3) (pyl = 2‐pyridyl) in methanol in basic medium, in the presence of carbon monoxide. The reaction conditions were determined and the products were spectroscopically characterized.
Chemical form of arsenic in marine macroalgae
Authors: Morita Masatoshi , Shibata Yasuyuki
Published: December 2004

Chemical forms of water‐soluble and lipid soluble arsenic compounds in marine macroalgae, including edible algae, are reviewed. Major watersoluble arsenic compounds inalgae are arseniccontaining ribofuranosides (ACRs). Red and green algae contain mainly a glycerophospho derivative at the glycerol terminal while brown algae contain a sulfate or sulfonate derivatives at the glycerol terminal together with a glycerophospho derivative. Brown algae which belong to the Sargasso species contain significant amounts of inorganic arsenic in the form of arsenate. Lipid‐soluble arsenic identified in a brown algae (Undaria pinnatifida) was an acylated derivative of an ACR. Thirty‐eight marine algae were analyzed by HPLC/ICP/MS and their arsenic compounds are characterized. The characterization of arsenic compounds may show their role in the chemical taxonomy of algae species in addition to giving an understanding of the toxicological and geochemical implication of the element.
Chemical form of arsenic compounds and distribution of their concentrations in the atmosphere
Authors: Nakamura Masaru , Matsuzono Yoshiaki , Tanaka Shigeru , Hashimoto Yoshikazu
Published: December 2004

In order to understand the chemical form of arsenic compounds and their distribution in unpoluted areas, concentrations of arsenic compounds in the marine atmosphere were measured in several islands in several oceans. Furthermore, concentration of arsenic compounds were also measured between Tokyo and the Syowa station during a cruise by the Antarctic observation boat Shirase. Aerosols in the marine atmosphere were collected by a high‐volume air sampler with a quartz fiber filter. After extracting a sample, an analysis of arsenic compounds in the sample solution was carried out by hydride generation atomic absorption spectrophotometry combined with a cold trap of liquid nitrogen. This technique has a high analytical sensivity, so that it is suitable to determine arsenic compounds at trace level.

The atmospheric concentrations of arsenic compounds were at the same level over the Pacific Ocean and the Atlantic Ocean. The concentration range of arsenic compounds over these oceans was 100–200 pg m−3 for inorganic arsenic, 10–20 pg m−3 for inorganic arsenic. It is considered that these values are the background concentrations in the northern hemisphere. On the other hand, over he Antarctic Ocean in the southern hemisphere, the atmospheric concentrations of inorganic arsenic were very low, and organic arsenics were little found. This fact indicates that arsenic in the atmosphere is strongly influenced by anthropogenic sources.
Comparative study on the tumorigenicity in mice of gallium arsenide, gallium phosphide and gallium oxide following subcutaneous and intraperitoneal injections
Authors: Tanaka Akiyo , Hisanaga Akira , Hirata Miyuki , Ishinishi Noburu
Published: December 2004

Chronic toxicity, including tumorigenicity, of gallium arsenide (GaAs), gallium phosphide (GaP) and gallium oxide (Ga2O3) was studied in male ICR mice which received either a subcutaneous or an intraperitoneal injection of each material once only. The doses received either subcutaneously or intraperitoneally were 48 mg Kg−1 as Ga or 480 mg Kg−1 as Ga of each material suspended in 0.2 cm3 of olive oil. The control groups received the vehicle only, either subcutaneously or intraperitoneally.

In the study using subcutaneous injections, no tumors were observed in the subcutis at the site of injection, and there was no significant difference concerning the survival periods of each group compared with the control group at the termination of the observation period.

In the study using intraperitoneal injections, the total tumor incidence in all the experimental groups, except for the GaAs (480 mg Ga Kg−1) groups, was significantly different compared with the control group. However, all these tumors appeared to be spontaneous, rather than induced by the materials themselves. Moreover, in the GaAs (480 mg Ga Kg−1) and Ga2O3 (48 mg Ga Kg−1) groups, the number of survival days was significantly lower compared with the control group.

From this study, it seems that neither GaAs, GaP nor Ga2O3 were tumorigenic to mice when injected subcutaneously. Although it remains unclear whether the increased production of total tumors in each group following intraperitoneal injections was directly due to the tumorigenic action of GaAs, GaP or Ga2O3 or not, it appears that these substances produce a potential systemic toxicity in mice following intraperitoneal injections.
Metabolism in mice of arsenic compounds contained in the red alga Porphyra yezoensis
Authors: Shiomi Kazuo , Chino Makoto , Kikuchi Takeaki
Published: December 2004

Arsenic compounds in the red alga Porphyra yezoensis were purified by gel filtration on Bio‐Gel P‐2; chromatographic behavior suggested that they were arsenic‐containing ribofuranosides (arsenosugars). When partially purified arsenosugars were orally administered to mice, 86% and 13% of the arsenic administered were excreted in feces and urine, respectively, within 48 h. Arsenic compounds excreted in feces were identified as arsenosugars by gel filtration and highperformance liquid chromatography, while those excreted in urine were identified as methylarsonic acid, dimethylarsinic acid and arsenobetaine. On the other hand, upon intravenous administration of arsenosugars, a large part of the arsenic administered was excreted rapidly in urine; after 72 h, 92% of the arsenic administered was recovered in urine and 6% in feces. Similarly to the case of oral administration, methylarsonic acid, dimethylarsinic acid and arsenobetaine were detected in urine.
Reactivity of isopropenylacetylene, HCCC(CH3)CH2, in the presence of the complex [Ni(NCS) {CCC(CH3)CH2}(PPh3)2]
Authors: Furlani A. , Russo M. V.
Published: December 2004

The reactivity of isopropenylacetylene (IP) in the presence of [Ni(NCS){CCC(CH3)CH2}(PPh3)2] has been examined. 1,2,4‐Tris(isopropenyl)benezene (1,2,4‐TIB), two isomeric tetramers formed by reaction of 1,2,4‐TIB with IP, and polymeric fractions have been separated and characterized by IR, NMR and mass spectra. Stability of reaction products towards oxygen and humidity has also been investigated.
Variability of butyltin determination in water and sediment samples from european coastal environments
Authors: Quevauviller Ph. , Donard O F X
Published: December 2004

A large amount of data has appeared in the literature within the last few years dealing with the monitoring of butyltin compounds in coastal environments. However, the strategies used strongly differed from one author to another, which led to difficulties in the comparison of contamination levels and the evaluation of long‐term trends. In this paper, different causes of pitfalls due to uncontrolled sources of variability are addressed; they involve precautions to be undertaken for the monitoring of butylins in water and sediment, particularly: sample collection; sample pretreatment (filtration/centrifugation, acidification, sieving); sample storage (different methods for storage and drying procedures); variability over the same site; variations over a tidal cycle; and variability due to diffusion (e.g. due to flushing).
Ionic alkyl‐lead, tetra‐alkyl‐lead and total lead in fish from the Great Lakes
Authors: Forsyth D S , Dabeka R W , Cleroux C
Published: December 2004

Fillets from a variety of fish species collected from Lakes Ontario, Superior and Erie, Canada, were examined for ionic alkyl‐lead, tetra‐alkyl‐lead and total lead compounds. Diphenylthiocarbazone (dithizone)‐derivatized extracts were collected at pH 8 and 9 for ionic alkyl‐leads from enzymatically hydrolyzed samples. Butylated derivatives were formed prior to analysis by gas chromatography‐atomic absorption spectrometry (GC AA). Tetra‐alkyl‐lead was extracted from the hydrolyzates with hexane.

Most of the fillets contained low (<0.08–2 ng g−1) levels of trimethyl‐lead. Several samples contained triethyl‐lead or tetraethyl‐lead. Dimethyl‐lead, diethyl‐lead and tetramethyl‐lead were detected by GC MS but were below the GC AA method detection limit of 0.06 ng g−1, 0.09 ng g−1 and 0.2 ng g−1 respectively. Total lead levels were between <1.8 and 96.7 ng g−1.
Pyrolysis of metallocene complexes (ηC5H4R)2MR: An organometallic route to metal carbide (MC) materials (M = Ti, Zr, Hf)
Authors: Lang Heinrich , Seyferth Dietmar
Published: December 2004

The following compounds were prepared and their pyrolysis in a stream of argon was studied: (η5‐C5H5)2Ti(CCC6H5)2, (η5‐C5H4SiMe3)2‐Ti(SH)2, [(η5‐C5H5)Ti(μ‐CH2)]2, (η5‐C5H5)2ZrR2‐(RCH2, CH2C6H5, N(CH3)2), (η5‐C5H4CH3)2‐Zr(CCC6H5)2, [(η5‐C5H4SiMe3)2Zr(μ‐S)]2, [(η5‐C5H4SiMe3)2Hf(μ‐S)]2 and (η5‐C5H4SiMe3)2Hf‐(CCC6H5)2. The products of bulk pyrolysis of these materials were formed in 20–40% yield, based on the charged sample weight, and consisted mainly of titanium carbide together with small amounts of amorphous carbon.