bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic modeling and behavior of the Confederation Bridge
Authors: Lau D T , Brown T , Cheung M S , Li W C
Published: April 2004

The Confederation Bridge is the world longest spanned prestressed concrete box girder bridge standing in salt water. This bridge is subjected to severe dynamic loads, such as transverse loads and vibrations, induced by strong winds and stormy sea waves, destructive seismic loads from possible ground shaking, and impact loads from heavy vehicles and huge ice floe. Therefore, the dynamic behavior of the bridge is a very important factor affecting its safety and serviceability. In the present study, a three-dimensional (3-D) model using shell elements is developed to investigate the free vibration behavior of one repetitive unit, while a frame model using 3-D beam elements is employed to simulate dynamic responses of two repetitive units with a drop-in span. The effects of nonstructural mass, pier–water interaction and foundation flexibility on free vibration behavior are also studied by means of the frame model. The results are representative for the entire bridge because of the repetitiveness in the bridge configuration. Further, field data from pull tests are used to calibrate the finite element models. Computer simulation of the pull test using the calibrated frame model correlates reasonably well with the field data.Key words: Confederation Bridge, numerical modeling, finite element model, model calibration, pull test, computer simulation.
Schistosoma mansonimale–female interactions
Authors: LoVerde Philip T , Niles Edward G , Osman Ahmed , Wu Wenjie
Published: April 2004

Schistosome parasites are muticellular eucaryotic organisms with a complex life cycle that involves mammalian and snail hosts. Unlike other trematode parasites, schistosomes (along with the Didymozoidae) have evolved separate sexes or dioecy. Sex is determined by a chromosomal mechanism. The dioecious state created an opportunity for the sexes to play a role in schistosome evolution that has resulted in an interesting interplay between the sexes. The classical observation, made more than 50 years ago, is that female schistosomes do not develop unless a male worm is present. Studies up through the 1990s focused on dissecting the role of the sexes in mate attraction, mate choice, mating behavior, female growth, female reproductive development, egg production, and other sex-evolved functions. In the mid-1980s, studies began to address the molecular events of male–female interactions. The classic morphological observation that female schistosomes do not complete reproductive development unless a male worm is present has been redefined in molecular terms. The male by an unknown mechanism transduces a signal that regulates female gene expression in a stage-, tissue-, and temporal-specific manner. A number of female-specific genes have been identified, along with signaling pathways and nuclear receptors, that play a role in female reproductive development. In addition, a number of host factors such as cytokines have also been demonstrated to affect adult male and female development and egg production. This review focuses on the biological interactions of the male and female schistosome and the role of parasite and host factors in these interactions as they contribute to the life cycle of Schistosoma mansoni.
Flatworm asexual multiplication implicates stem cells and regeneration
Authors: Reuter Maria , Kreshchenko Natalia
Published: April 2004

The phenomenon of asexual multiplication is rare in the animal kingdom, but it occurs in all main flatworm taxa. In the present paper, we review data regarding the presence of different forms of asexual multiplication in flatworms and argue that the presence of a population of totipotent or pluripotent stem cells, "neoblasts", is a primitive feature of decisive importance for the developing potential of flatworms. Next we present information on the role of stem cells in fission, head regeneration, and pharynx regeneration of planarians. Furthermore, the tracing of neoblasts in lower flatworms and cestodes is presented, and the results indicating heterogeneity of the neoblast pool are discussed. Finally, the mode by which the neoblasts are stimulated to divide, migrate, and differentiate and the nature of the interactions are discussed. We focus on (i) biogenic amines and neuropeptides, (ii) the role of neuropeptides in the early stage of regeneration, (iii) the evidence for the influences of growth factors and nitric oxide, and (iv) the influence of weak electromagnetic fields. We discuss the pattern in which a gradient system of morphogens and (or) a hierarchical system of inductions is expressed in development.
Genome and genomics of schistosomes
Authors: Oliveira Guilherme , Rodrigues Nilton B , Romanha Alvaro J , Bahia Diana
Published: April 2004

Schistosomes infect over 200 million people and 600 million are at risk. Genomics and post-genomic studies of schistosomes will contribute greatly to developing new reagents for diagnostic purposes and new vaccines that are of interest to the biotechnology industry. In this review, the most recent advances in these fields as well as new projects and future perspectives will de described. A vast quantity of data is publicly available, including short cDNA and genomic sequences, complete large genomic fragments, and the mitochondrial genomes of three species of the genus Schistosoma. The physical structure of the genome is being studied by physically mapping large genomic fragments and characterizing the highly abundant repetitive DNA elements. Bioinformatic manipulations of the data have already been carried out, mostly dealing with the functional analysis of the genes described. Specific search tools have also been developed. Sequence variability has been used to better understand the phylogeny of the species and for population studies, and new polymorphic genomic markers are currently being developed. The information generated has been used for the development of post-genomic projects. A small microarray detected genes that were differentially expressed between male and female worms. The identification of two-dimensional spots by mass spectrometry has also been demonstrated.
Comparative morphology of the body wall in flatworms (Platyhelminthes)
Authors: Tyler Seth , Hooge Matthew
Published: April 2004

The soft-bodied nature of the platyhelminths is due largely to the structure of the body wall and its lack of sclerotic elements such as cuticle. Free-living members, i.e., most turbellarians, show considerable variety, but the basic form of the body wall comprises a simple ciliated epithelium overlying a network of muscles. We illustrate this body wall structure in a representative typhloplanoid rhabditophoran and discuss variations in representatives of the Acoela, Catenulida, and other free-living rhabditophorans. The major parasitic groups of platyhelminths, the rhabditophoran Neodermata, follow a developmental pattern that replaces a similar ciliated epidermis in a larval stage with a specialized epidermis called a neodermis, which is assumed to be key to their success as parasites. This neodermis consists of a syncytium that covers the body in a continuous sheet connected to perikarya that lie below the body wall musculature. The neodermis can be seen as a special adaptation of a developmental mechanism common to all platyhelminths, in which epidermal growth and renewal are accomplished by replacement cells originating beneath the body wall. The cell type responsible for all cell renewal, including body wall renewal, in platyhelminths is the neoblast, and its presence may be the one autapomorphic character that unites all taxonomic groups of platyhelminths.
Studies on platyhelminths: yesterday, today, and tomorrow
Authors: Webb Rodney A
Published: April 2004

This introduction to the following collection of review articles discusses briefly why some researchers chose to study platyhelminths, especially parasites, and some of the important principles and concepts that emerge from these reviews. One observation is that these are challenging animals to work with. Although much has emerged of note, much remains to be done and this introduction highlights a few of these areas.
SIMULTANEOUS AVOIDANCE OF LARGE SQUARES AND FRACTIONAL POWERS IN INFINITE BINARY WORDS
Authors: SHALLIT JEFFREY
Published: April 2004

In 1976, Dekking showed that there exists an infinite binary word that contains neither squares yy with |y|≥4 nor cubes xxx. We show that 'cube' can be replaced by any fractional power > 5/2. We also consider the analogous problem where '4' is replaced by any integer. This results in an interesting and subtle hierarchy.
REPETITIONS, FULLNESS, AND UNIFORMITY IN TWO-DIMENSIONAL WORDS
Authors: CARPI ARTURO , de LUCA ALDO
Published: April 2004

We consider some combinatorial properties of two-dimensional words (or pictures) over a given finite alphabet, which are related to the number of occurrences in them of words of a fixed size (m,n). In particular a two-dimensional word (briefly, 2D-word) is called (m,n)-full if it contains as factors (or subwords) all words of size (m,n). An (m,n)-full word such that any word of size (m,n) occurs in it exactly once is called a de Bruijn word of order (m,n). A 2D-word w is called (m,n)-uniform if the difference in the number of occurrences in w of any two words of size (m,n) is at most 1. A 2D-word is called uniform if it is (m,n)-uniform for all m,n>0. In this paper we extend to the two-dimensional case some results relating the notions above which were proved in the one-dimensional case in a preceding article. In this analysis the study of repeated factors in a 2D-word plays an essential role. Finally, some open problems and conjectures are discussed.
AN ANNEALED CHAOTIC MAXIMUM NEURAL NETWORK FOR BIPARTITE SUBGRAPH PROBLEM
Authors: WANG JIAHAI , TANG ZHENG , WANG RONGLONG
Published: April 2004

In this paper, based on maximum neural network, we propose a new parallel algorithm that can help the maximum neural network escape from local minima by including a transient chaotic neurodynamics for bipartite subgraph problem. The goal of the bipartite subgraph problem, which is an NP–complete problem, is to remove the minimum number of edges in a given graph such that the remaining graph is a bipartite graph. Lee et al. presented a parallel algorithm using the maximum neural model (winner-take-all neuron model) for this NP–complete problem. The maximum neural model always guarantees a valid solution and greatly reduces the search space without a burden on the parameter-tuning. However, the model has a tendency to converge to a local minimum easily because it is based on the steepest descent method. By adding a negative self-feedback to the maximum neural network, we proposed a new parallel algorithm that introduces richer and more flexible chaotic dynamics and can prevent the network from getting stuck at local minima. After the chaotic dynamics vanishes, the proposed algorithm is then fundamentally reined by the gradient descent dynamics and usually converges to a stable equilibrium point. The proposed algorithm has the advantages of both the maximum neural network and the chaotic neurodynamics. A large number of instances have been simulated to verify the proposed algorithm. The simulation results show that our algorithm finds the optimum or near-optimum solution for the bipartite subgraph problem superior to that of the best existing parallel algorithms.
COSMIC ORIGIN OF QUANTIZATION
Authors: CALOGERO FRANCESCO
Published: April 2004

An estimate is presented of the angular momentum associated with the stochastic cosmic tremor, which has been hypothesized to be caused by universal gravitation and by the granularity of matter, and to be itself the cause of quantization ("cosmic origin of quantization"). If that universal tremor has the spatial coherence which is instrumental in order that the estimated action associated with it have the order of magnitude of Planck's constant h, then the estimated order of magnitude of the angular momentum associated with it also has the same value. We moreover indicate how these findings (originally based on a simplified model of the Universe, as being made up only of particles having the nucleon mass) are affected (in fact, essentially unaffected) by the possible presence in the mass of the Universe of a large component made up of particles much lighter than nucleons ("dark", or "missing", mass).
SPIN-1 GRAVITATIONAL WAVES
Authors: CANFORA FABRIZIO , VILASI GAETANO , VITALE PAOLA
Published: April 2004

Gravitational fields invariant for a 2-dimensional Lie algebra of Killing fields [X,Y]=Y, with Y of light type, are analyzed. The conditions for them to represent gravitational waves are verified and the definition of energy and polarization is addressed; realistic generating sources are described.
QUANTUM TIMING AND SYNCHRONIZATION PROBLEMS
Authors: DE FALCO DIEGO , TAMASCELLI DARIO
Published: April 2004

Feynman's model of a quantum computer provides an example of a continuous-time quantum walk. Its clocking mechanism is an excitation of a basically linear chain of spins with occasional controlled jumps which allow for motion on a planar graph. The spreading of the wave packet poses limitations on the probability of ever completing the s elementary steps of a computation: an additional amount of storage space δ is needed in order to achieve an assigned completion probability. In this note we study the END instruction, viewed as a measurement of the position of the clocking excitation: a π-pulse indefinitely freezes the contents of the input/output register, with a probability depending only on the ratio δ/s.
MULTIPHOTON SQUEEZED STATES BY CUBIC NONLINEAR CONTRIBUTION
Authors: DELL'ANNO FABIO , DE SIENA SILVIO , DI LISI ANTONIO , ILLUMINATI FABRIZIO
Published: April 2004

In this paper we study the properties of Multiphoton Squeezed States (MpSS) obtained by homodyne nonlinear canonical transformations (HNCT), in which the nonlinear term is a cubic power of the second field quadrature P. In particular, we analyze the Hamiltonian structure and the field statistics associated with these states. Finally we provide a phase space analysis by means of the Wigner functions of these states.
A STOCHASTIC MODEL FOR MULTIFRACTAL BEHAVIOR OF STOCK PRICES
Authors: FULCO UMBERTO L. , LYRA MARCELO L. , PETRONI FILIPPO , SERVA MAURIZIO , VISWANATHAN GANDHI M.
Published: April 2004

We investigate the general problem of how to model the kinematics of stock prices without considering the dynamical causes of motion. We propose a Markovian stochastic process which is able to reproduce the experimentally observed volatility clustering and fat tails in the probability density functions (PDF) of financial time series. More importantly, the process also reproduces the PDF time scaling, the power law memory of volatility and the apparent multifractality of the time series up to the time scale which is experimentally observable.
TOPOLOGY INDUCED MACROSCOPIC QUANTUM COHERENCE IN JOSEPHSON JUNCTION NETWORKS
Authors: GIUSIANO GIOVANNI , MANCINI FRANCESCO P. , SODANO PASQUALE , TROMBETTONI ANDREA
Published: April 2004

We argue that Josephson junction networks may be engineered to allow for the emergence of new and robust quantum coherent states. We provide a rather intuitive argument showing how the change in topology may affect the quantum properties of a bosonic particle hopping on a network. As a paradigmatic example, we analyze in detail the quantum and thermodynamical properties of non-interacting bosons hopping on a comb graph. We show how to explicitly compute the inhomogeneities in the distribution of bosons along the comb's fingers, evidencing the effects of the topology induced spatial Bose–Einstein condensation characteristic of the system. We propose an experiment enabling to detect the spatial Bose–Einstein condensation for Josephson networks built on comb graphs.
A FOOTNOTE TO NELSON'S INTERPRETATION OF THE TWO-SLIT EXPERIMENT
Authors: PAVON MICHELE
Published: April 2004

We seek to complement Nelson's work on the two-slit experiment by showing that the two-slit process, whose density exhibits the characteristic interference pattern, may be obtained as the model after the beam has reached the screen by means of a variational mechanism. The one-slit process, modeling the beam before it reaches the screen, plays the role of a reference model.
MAGNETIZATION OF THE PURE STATES IN THE p-SPIN INTERACTION MODEL
Authors: TALAGRAND M.
Published: April 2004

We study the magnetization of the pure states in (a suitable version of) the p-spin interaction model at low temperature. We give a rigorous proof of the phenomenon, discovered in 1 that (very roughly speaking), at a given level of accuracy, the set of sites decomposes in a finite number of cells on which the magnetization of any different pure states are uncorrelated.
LISTENING: SOUND STREAM AS A CLOCK
Authors: TEDESCHINI-LALLI LAURA
Published: April 2004

Sound happens in time. Human ears detect more objective regularities of a sonic flow, than those we are in general able to describe, yet. We review some studies of sound in the time-domain. Sound streams to be detected by human ears have a hierarchical organization. This can also be seen on the time-organization of entropic flow of the signal, that we choose as variable. We describe an experiment where ability to synchronize by ear a spoken signal with another signal of disturbs is matched to the entropic content of the spoken signal; i.e. the disturb is placed more precisely if it happens in areas of high entropy. This study is phenomenological.
LIAO STYLE NUMBERS OF DIFFERENTIAL SYSTEMS
Authors: DAI XIONGPING
Published: April 2004

For any C1differential system S on a compact Riemannian manifold M of dimension d with d≥2, this paper studies the Liao style numbers, κ(S) (or respectively, κ*(S)) of S from the view-point of ergodic theory. Here κ(S) (κ*(S)) is the largest number of moving vectors (or respectively, conjugate-) of the differential system S that are mean linearly independent. For any ergodic measure ν of S, two positive integers κ*(ν) and κ(ν), called the reduced and non-reduced style number of ν respectively, are introduced. The connection between the style numbers of the system (M,S) and ones of the ergodic system (M,S; ν) are discovered by the variational principle of style number proved in the paper. Several characterization theorems with respect to the style numbers κ*(S), κ*(ν), κ(S) and κ(ν) are presented respectively.
ONSET OF INSTABILITY IN HYDROMAGNETIC COUETTE FLOW
Authors: HERRON ISOM H.
Published: April 2004

The stability of viscous flow between rotating cylinders in the presence of a constant axial magnetic field is considered. The boundary conditions for general conductivities are examined. It is proved that the Principle of Exchange of Stabilities holds at zero magnetic Prandtl number, for all Chandrasekhar numbers, when the cylinders rotate in the same direction, the circulation decreases outwards, and the cylinders have insulating walls. The result holds for both the finite gap and the narrow gap approximation.
ENABLING TECHNOLOGIES FOR THE CREATION AND RESTRUCTURING PROCESS OF EMERGENT ENTERPRISE ALLIANCES
Authors: ULIERU MIHAELA , UNLAND RAINER
Published: April 2004

In today's world, it is of utterly importance for enterprises to react in a timely and flexible way to upcoming complex market demands. One solution is given by the concept of virtual enterprise and enterprise alliances, respectively. In order to function efficiently and flexibly such enterprises need to be deeply integrated. Based on previous work combining the concepts of virtual enterprises, holonic organizations and multi-agent systems to support such deep integration, the paper discusses in detail how well-suiting partners and contributors for a given (bunch of) task(s) can be found using today's state-of-the-art technologies. Mapping an enterprise alliance onto a multi-agent system is enabled by a methodology equipping each agent with the ability to deal and consider its own goals (goals of the unit it represents) as well as the goals of the unit in which it is integrated (the higher level unit).
RECEDING HORIZON FUZZY OPTIMIZATION UNDER LOCAL INFORMATION ENVIRONMENT WITH A CASE STUDY
Authors: LI SHAO-YUAN , WU HU , YANG YI-PENG
Published: April 2004

Model predictive control (MPC) has been used in process control systems with constraints; however, the constrained optimization problem involved in control systems has generally been solved in practice in a piece-meal fashion. To solve the problem systemically, in this paper, the Multi-Objective Fuzzy-Optimization (MOFO) is used in the constrained predictive control for online applications as a means of dealing with fuzzy goals and fuzzy constraints in control systems. The conventional model predictive control is integrated with the techniques from fuzzy multi-criteria decision making, translating the goals and the constraints to predictive control in a transparent way. The information regarding the fuzzy goals and the fuzzy constraints of the control problem is combined by using a decision function from the fuzzy theory, so it is possible to aggregate the fuzzy goals and the fuzzy constraints using fuzzy operators, e.g. t-norms, s-norms or the convex sum. It is shown that the model predictive controller based on MOFO allows the designers for a more flexible aggregation of the control objectives than the usual weighting sum of squared errors in MPC. The visual robot path planning validates the efficiency of the presented algorithm.
TOWARDS A GENERIC OBJECT ORIENTED DECISION SUPPORT SYSTEM FOR UNIVERSITY TIMETABLING: AN INTERACTIVE APPROACH
Authors: PIECHOWIAK SYLVAIN , KOLSKI CHRISTOPHE
Published: April 2004

Timetable management in universities is a complicated issue which uses up a great deal of human resources and is therefore very costly. This article deals with the analysis and design of an interactive decision support system for timetable management. This tool will be able to take hierarchical data organization into account and maintain coherence of the constraints on this data. Our research which has led to the creation of the [Formula: see text] tool has three aims. The first aim is to provide an open, generic tool which can be developed in many different ways. In order to achieve these aims, we have followed an object-oriented approach and we have defined object classes dedicated for the modelling of the timetabling problem. The second aim is to analyze the needs in timetable manipulation and to provide a generic organization so that the tool can be used in many structures. The third and final aim is to provide a easy to handle tool which can be used by various user profiles on personal computers with a low processing power.
Negotiating the Clouds Around Statistics and "Q": a Rejoinder and Independent Analysis
Authors: Mattila Sharon Lea
Published: April 2004

In 1994, the author critiqued a 1971 statistical study of "Q" by Charles E. Carlston and Dennis Norlin. Their recent reply has necessitated both a further clarification of their study's most serious flaws and an independent statistical analysis using a method that avoids these flaws. Such an analysis demonstrates that Matthew and Luke do not preserve "Q" sayings any more faithfully than Markan sayings. This can still be interpreted in support of "Q" being a single written source, but it is important to recall that the degree of Matt-Luke verbatim agreement is much lower than Carlston & Norlin's figures imply.
Ebenmass Im Epheserbrief: Stichometrische Kompositionsanalyse
Authors: Lang Friedrich Gustav
Published: April 2004

Der Epheserbrief hat eine ausgefeilte symmetrische Struktur. Mittlerer Hauptteil ist 4,1-16; inhaltlich überlappen sich darin Ekklesiologie und Ethik, die beiden Themen der Teile davor bzw. danach. Dem entspricht die formale Disposition, die hier erstmals konsequent stichometrisch analysiert wird. Als Maßzeile dient der 15-Silben-Stichos. Die Textabschnitte 1,1-3,21 und 4,17-6,24 haben genau denselben Zeilenumfang, ebenso die Hauptteile 1,3-2,10 und 2,11-3,21; die Teile 4,17-5,14 und 5,15-6,24 stehen exakt im Verhältnis 2:3. Jeweils sind Bausteine von 21, 13 oder 8 Stichoi verwendet. Die Symmetrie im Briefaufbau erinnert an Körperbau und Tempelbau, kaum zufällig, denn im Epheserbrief ist beides Bild für die Kirche.
Connective-tissue growth factor modulates WNT signalling and interacts with the WNT receptor complex
Authors: Mercurio Sara , Latinkic Branko , Itasaki Nobue , Krumlauf Robb , Smith J. C.
Published: April 2004

Connective-tissue growth factor (CTGF) is a member of the CCN family of secreted proteins. CCN family members contain four characteristic domains and exhibit multiple activities: they associate with the extracellular matrix,they can mediate cell adhesion, cell migration and chemotaxis, and they can modulate the activities of peptide growth factors. Many of the effects of CTGF are thought to be mediated by binding to integrins, whereas others may be because of its recently identified ability to interact with BMP4 and TGFβ. We demonstrate, using Xenopus embryos, that CTGF also regulates signalling through the Wnt pathway, in accord with its ability to bind to the Wnt co-receptor LDL receptor-related protein 6 (LRP6). This interaction is likely to occur through the C-terminal (CT) domain of CTGF,which is distinct from the BMP- and TGFβ-interacting domain. Our results define new activities of CTGF and add to the variety of routes through which cells regulate growth factor activity in development, disease and tissue homeostasis.
Evidence-Based Guidelines in Laboratory Medicine: Principles and Methods
Authors: Oosterhuis Wytze P , Bruns David E , Watine Joseph , Sandberg Sverre , Horvath Andrea R
Published: April 2004

Background: Guidelines are commonly used tools for supporting medical decisions. Formulating evidence-based recommendations has become a leading principle in guideline development.

Aim: This narrative review integrates the most recent methods of evidence-based guideline development and adapts those to the field of laboratory medicine.

Summary: We present a 10-step process and a list of criteria for the development of laboratory guidelines. Laboratory guidelines should be outcome oriented, be developed by a multidisciplinary team, and begin with a clear statement of the clinical question(s) that the use of the test(s) is addressing. The clinical questions define the type of study designs that offer the best evidence to answer those questions. Guidelines should be based on the critical appraisal and systematic review of literature and explicitly state the strength of evidence supporting each recommendation. Pragmatic considerations dictate that priority is given to topics with the highest clinical or economic impact. Scientific evidence is necessary but insufficient for recommendations, as considered judgment is required about benefits, harms, costs, and local applicability of recommendations. Formal consensus methods are needed when the evidence base is lacking or controversial. Guidelines should be disseminated widely and their impact monitored regularly. Regular reviewing is needed because the lack of timely updates is a major cause of nonadherence to guidelines.

Conclusions: Guidelines should be developed in a transparent process by a multidisciplinary team, with graded recommendations based on critically appraised scientific studies. Systematic, standardized, and explicit methodology, adapted to laboratory medicine, should be followed when developing recommendations involving the use of laboratory tests.
Solvent extraction and separation of thorium(IV) and uranium(VI) by an ether-amide type tripodand
Authors: Zhijun Guo , Weiguang Zhang , Yanning Niu , Minyu Tan
Published: April 2004

1,1,1-tris(N,N-diisobutylcarbamoyl-methyleneoxymethyl)propane (L) has been prepared and characterized by using IR, 1H NMR and positive-ion FAB mass spectra. The extraction of Th4+ and UO2
2+ with L was studied as a function of concentration of free extractant in an organic phase and of picrate in an aqueous phase from a picrate-nitrate medium at 293±1K. It was found that the extractability of L for Th4+ is larger than that for UO2
2+. Both extraction % of Th4+ and UO2
2+ decreased with an increase in the concentration of HNO3. The mechanism of extraction of Th4+ with L was proposed. The composition of extracted species of L with Th4+ in the organic phase is ThL(Pic)2(NO3)2. The results of extraction of trace 234Th4+ with L from the picrate-nitrate medium containing UO2
2+ (the initial concentration of UO2
2+, C
0
UO₂²⁺=1.23×10-4mol/dm3 (M)) agreed well with those from the extraction of single component solutions. The tripodand is useful in separation of Th4+ and UO2
2+ from each other in picrate-nitrate media with a relatively high separation factor.
Extraction of rubidium and caesium from strongly alkaline media
Authors: Dozol J. F. , Asfari Z. , Arnaud-Neu Francoise , Vicens J. , Thuéry P.
Published: April 2004

Huge amounts of alkaline liquid waste containing a high sodium salt concentration (and in some cases, a lesser potassium salt concentration) are contaminated by 137caesium. Selective removal of radioactive caesium ions, present in the waste at trace level, requires very selective extractants since the ratio of sodium over caesium exceeds 105. As expected, calix[4]arene-crown-6 is satisfactory for the extraction of caesium from liquid waste containing large amounts of sodium. The presence of potassium, which competes more than sodium with caesium, leads to a drastic caesium distribution coefficient decrease as the concentration of this competing cation increases. On the contrary, calix[4]arene and p-tert-butylcalix[4]arene, efficient extractants in high alkalinity media, display an exceptional selectivity for caesium over other alkaline cations, including rubidium. This selectivity of p-tert-butylcalix[4]arene, and to a lesser extent of calix[4]arene, allows caesium to be extracted from alkaline solutions containing large amounts of sodium and potassium.
Lack of association or linkage disequilibrium between schizophrenia and polymorphisms in the 5‐HT1Dα and 5‐HT1Dβ autoreceptor genes: Family‐based association study
Authors: Ambrósio Alda M. , Kennedy James L. , Macciardi Fabio , Coelho Isabel , Soares Maria J. , Oliveira Catarina R. , Pato Carlos N.
Published: April 2004

Genetic factors play a major role in the etiology of schizophrenia and disturbances of serotonergic pathways have been implicated in this disorder. The aim of the present study was to examine genetic association between schizophrenia and polymorphisms in the 5‐HT1Dα (TaqI) and 5‐HT1Dβ (T261G and G861C) autoreceptor genes in ninety trios from Portugal. No association or linkage disequilibrium was obtained between schizophrenia and 5‐HT1Dα and 5‐HT1Dβ autoreceptor genes with both haplotype relative risk (HRR) and transmission disequilibrium test (TDT). Concerning 5‐HT1Dβ autoreceptor gene, also negative results was obtained in the analysis of the haplotypes with transmit. Thus, our data provide no support for the hypothesis that polymorphisms at 5‐HT1Dα (TaqI) and 5‐HT1Dβ (T261G and G861C) genes contributes to susceptibility to schizophrenia in the Portuguese population. © 2004 Wiley‐Liss, Inc.
Dye‐molecular‐imprinted polysiloxanes. II. Preparation, characterization, and recognition behavior
Authors: Gong Shu‐Ling , Yu Zhao‐Ju , Meng Ling‐Zhi , Hu Ling , He Yong‐Bing
Published: April 2004

Microsphere silica (AMS) was prepared by the sol–gel method and used for the synthesis of dye‐molecular‐imprinted polysiloxanes. These were prepared by the cohydrolysis and polycondensation of the AMS with functional organosilicone monomers (N‐phenylaminomethyl triethoxysilane, 3‐aminopropyl triethoxysilane, and 4‐aza‐6‐aminohexyl triethoxysilane) in the presence of a template molecule of disperse red (or disperse blue or water‐soluble dye) followed by the removal of the template molecule. The molecular‐imprinting and nonimprinting polysiloxanes were characterized by elemental analysis, diffuse‐reflectance Fourier transform infrared spectroscopy, and scanning electron microscopy. Their adsorption behavior toward the template molecule and nontemplate molecule was investigated. The molecular‐imprinting polysiloxane exhibited higher selective recognition properties toward the template molecule than the nonimprinting polysiloxane. In the experimental conditions, their adsorption isotherms were a good fit with the Langmuir model. The distribution coefficient value of water‐soluble‐dye‐imprinted polysiloxane was the highest among the three imprinting polysiloxanes under the experimental conditions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 637–643, 2004
Modification of a Fischer‐Tropsch wax by grafting with maleic anhydride
Authors: Novák I. , Krupa I. , Luyt A. S.
Published: April 2004

The polarity of a hard Fischer‐Tropsch paraffin wax was improved through grafting of maleic anhydride (MA) initiated by dibenzoyl peroxide (DBP), which is reflected by a significant increase in the polar component of the surface free energy. MA and DBP concentrations of 3 wt % each are sufficient for significant modification of the polarity of the wax. FTIR spectra confirm the presence of anhydride groups on the wax chains, while gel permeation chromatograms show the development of a low molecular weight peak, which may be indicative of wax degradation. The grafting of wax by MA decreases the specific enthalpy of melting, as determined through differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 662–668, 2004
Correlation of Density Pedestal Width and Neutral Penetration Length
Authors: Xu X. Q. , Nevins W. M. , Cohen R. H. , Rognlien T. D. , Umansky M. V.
Published: April 2004

Pedestal studies in DIII‐D and MAST find good correlation between the width of the H‐mode density barrier and the neutral penetration length [1, 2]. These results suggest that the width may be set by the combined effects of neutrals and plasma transport. This paper is a report on fluid simulations of boundary plasma using the BOUT code[3] with a neutral source added. Thus both neutral and plasma physics are treated. The plasma transport is self‐consistently driven by boundary turbulence due to the resistive X‐point mode, while neutrals are described by a simple analytic model. The plasma profiles are evolved on the same time scale as the turbulence for the given heat source from the core plasma and particle source from the neutrals. For prescribed neutral profiles, we find the formation of a density pedestal inside the separatrix in the L‐mode even though the calculated plasma diffusion coefficients are almost radially constant and without the formation of a temperature pedestal. These results support the hypothesis that particle fueling can provide the dominant control for the size of the H‐mode density barrier. The width of the density barrier decreases as the pedestal density increases which is also consistent with experimental data. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Instability Driven by Sheath Boundary Conditions and Limited to Divertor Legs
Authors: Ryutov D. D. , Cohen R. H.
Published: April 2004

An instability driven by electron temperature gradient in combination with sheath boundary condition at the divertor plate is considered. A mode localized between the divertor plate and the X point is found. The further propagation of the mode is terminated by a strong shear near the X point. “Heuristic” boundary condition at the control surface situated somewhat below the X point is suggested. The mode manifests a strong dependence on the radial tilt of the divertor plate, thereby providing some degree of control over the plasma transport in the divertor leg. Estimates of the diffusion coefficient show that it may reach the Bohm value. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Universality of Intermittent Convective Transport in the Scrape‐off Layer of Magnetically Confined Devices
Authors: Antar Ghassan Y.
Published: April 2004

This article describes briefly recent results on the universality of intermittent convective transport reported in the scrape‐off layer. We show that the statistical properties of turbulence are identical for four different magnetic fusion devices. The four devices are the PISCES linear plasma device, the Tore Supra tokamak with limiter configuration, the Alcator C‐MOD with divertor configuration and high magnetic field, and theMAST spherical tokamak where the walls are far from the last closed flux surface (LCFS). These four devices do not only have different magnetic configurations but also have four different probes designs. Nine different types of statistical analyses are used, here we present just a few. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homoclinic tangles, bifurcations and edge stochasticity in diverted tokamaks
Authors: Evans T. E. , Roeder R. K. W. , Carter J. A. , Rapoport B. I.
Published: April 2004

The boundary and pedestal region of a poloidally diverted tokamak is particularly susceptible to the onset of vacuum magnetic field stochasticity due to small non‐axisymmetric resonant perturbations. Recent calculations of the separatrix topology in diverted tokamaks, when subjected to small magnetic perturbations, show the existence of complex invariant manifold structures known as homoclinic tangles. These structures appear above a relatively low perturbation threshold that depends on certain equilibrium shape parameters. Homoclinic tangles represent a splitting of the unperturbed separatrix into stable and unstable invariant manifolds associated with each X‐point (hyperbolic point). The manifolds that make up homoclinic tangles set the boundaries that prescribe how stochastic field line trajectories are organized i.e., how field lines from the inner domain of the unperturbed separatrix mix and are transported to plasma facing surfaces such as divertor target plates and protruding baffle structures. Thus, the topology of these tangles determines which plasma facing components are most likely to interact with escaping magnetic field lines and the parallel heat and particle flux they carry. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A 1‐D diffusive transport model for the density and temperature of edge neutrals
Authors: Owen L. W. , Moiduszewski P. K.
Published: April 2004

A one‐dimensional (1‐D) model of neutral transport in edge plasmas is shown to reproduce the results of Monte Carlo simulations for a variety of edge plasma profiles. The transport of hydrogenic atoms is assumed to be diffusive with a flux limit that depends on the neutral mean‐free path and gradients of plasma density and ion temperature. The steady‐state continuity equation and a simple first order equation for the energy transfer between ions and neutral atoms are solved for the neutral atom density and temperature along the normal to the recycling (source) surface. Based upon particle and energy reflection coefficients for carbon, recycling is simulated with fluxes of both energetic reflected atoms and desorbed molecules. Assuming convective transport with constant velocity, the continuity equation for molecules is solved for the molecular density, which is shown to agree with Monte Carlo if flux enhancement due to backscattered atoms is included. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Expression analysis of the Drosophila pipsqueak family members fernández/distal antenna and hernández/distal antenna related
Authors: Suzanne Magali
Published: April 2004

The “pipsqueak” family is composed of proteins that contain a pipsqueak motif, a previously characterised DNA binding domain, and thus represents a new family of potential transcription factors. Previous functional characterisation of several Drosophila genes encoding pipsqueak domain‐containing proteins has shown their crucial role in development. Here, I report the embryonic, larval, and pupal expression pattern of two Drosophila genes, fernández/distal antenna and hernández/distal antenna related, which encode protein members of the pipsqueak family with similar pipsqueak motifs. Furthermore, I show that, consistently with their expression pattern, these two genes are required in the nervous system during the embryonic development. Developmental Dynamics 230:361–365, 2004. © 2004 Wiley‐Liss, Inc.
Adding value to vegetable waste: Oil press cakes as substrates for microbial decalactone production
Authors: Laufenberg Günther , Rosato Pietro , Kunz Benno
Published: April 2004

In this study several oil press cakes were investigated as exclusive substrates for different moulds and yeasts for the production of flavor‐active decalactones via solid‐state fermentation (SSF). Experiments are focused on pre‐treatment methods for olive cake to remove antimicrobial phenolic substances contained in the oil cake disturbing or even inhibiting microbial growth. Choosing Ceratocystis moniliformis as the reference microorganism best results were obtained by a combination of hot water flushes and enzymatic treatment of the cake. Fermentation with sunflower, olive and linseed cake did not lead to lactone formation in detectable amounts although all of these substrates provided good microbial growth. On castor cake, however, five microorganisms have synthesized the requested decalactones via SSF. Thus fermentation of the fungus Moniliella suaveolens on this substrate resulted in a maximum concentration of γ‐decalactone of 180.7 mg·kg−1 dry matter without optimization. Another δ‐lactone, 6‐pentyl‐α‐pyrone, was produced in small amounts by the fungus Trichoderma harzianum on castor cake.
Carbon monoxide and oxidative stress inDesulfovibrio desulfuricansB‐1388
Authors: Davydova M. , Sabirova R. , Vylegzhanina N. , Tarasova N.
Published: April 2004

It has been shown that carbon monoxide (CO) in low concentration may be an active biochemical and physiological regulator of cell function. The bases of CO toxicity and cell protection are not clearly understood. To provide insights into these mechanisms, we measured superoxide production byD. desulfuricansB‐1388 incubated anaerobically in Postgate medium with or without 5% CO.D. desulfuricansB‐1388 growing with CO in the gas phase produced more superoxide radicals then control cells growing in Ar. When the cells were pregrown with CO, NADH oxidase and peroxidase activities were increased. The increase in peroxidase activities of cells growing under CO (particularly NADH peroxidase) suggested that H2O2was accumulated in cells. Superoxide dismutase (SOD) activity of cells decreased in exponential growth phase and increased in stationary phase. This may be due to CO concentration fall during CO oxidation by CO dehydrogenase. Altogether, our data suggest that superoxide production is a possible mechanism of CO toxicity. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:87–91, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20011
Evaluation of the reproducibility of intrarenal R and ΔR measurements following administration of furosemide and during waterload
Authors: Li Lu‐Ping , Storey Pippa , Pierchala Linda , Li Wei , Polzin Jason , Prasad Pottumarthi
Published: April 2004

Purpose

To estimate the reproducibility of BOLD MRI measurements in the evaluation of intrarenal oxygenation levels.

Materials and Methods

In this study, the reproducibility of semiquantitative BOLD MRI measurements performed on a 1.5 T scanner with a multiple gradient‐echo sequence in the renal medulla and cortex, and their response to furosemide and waterload, were assessed in eight healthy young subjects (25.6 ± 4.1 years). Each subject underwent an identical experimental procedure on two separate days.

Results

Renal R measurements were shown to be reproducible within ∼12% from day to day based on a coefficient of variance (CV) analysis. The changes in R (ΔR) following administration of furosemide were statistically significant, as shown by ANOVA and a paired Student's t‐test, and were deemed reliable based on the reliable change index (RCI). However, ΔR values following waterload were not statistically significant, and were not deemed reliable.

Conclusion

R measurements were reproducible over 270 days within 12%. Furosemide produced a significant and reliable change (∼30%), and the magnitude of change (5.7 s−1) was reproducible and consistent with our previous data. The response to waterload, however, did not reach statistical significance, and the magnitude did not reach the level that we had previously reported. J. Magn. Reson. Imaging 2004;19:610–616. © 2004 Wiley‐Liss, Inc.
Dependence of calcium influx in neocortical cells on temporal structure of depolarization, number of spikes, and blockade of NMDA receptors
Authors: Balaban Pavel , Chistiakova Marina , Malyshev Aleksey , Volgushev Maxim
Published: April 2004

Increase of intracellular [Ca2+] evoked by action potentials in a cell can induce long‐term synaptic plasticity even without concomitant presynaptic stimulation. We used optical recording of the fluorescence of a Ca2+‐indicator Oregon Green to investigate whether differences in results obtained with modifications of that purely postsynaptic induction protocol could be due to differential Ca2+ influx. We compared changes of the somatic [Ca2+] in layer II–III pyramidal cells in slices of rat visual cortex evoked by bursts of depolarization pulses and long depolarizing steps. During weak depolarizations, the Ca2+ influx was proportional to the amplitude and duration of the depolarization. With suprathreshold depolarizations, the Ca2+ influx was proportional to the number of action potentials. Because the burst depolarizations evoked more spikes than did the long duration steps, this burst protocol led to a larger Ca2+ influx. With all stimulation protocols, the spike‐induced Ca2+ influx was reduced during blockade of N‐methyl‐D‐aspartate (NMDA) receptors. Differences in intracellular [Ca2+] increases thus may be one reason for differential effects of purely postsynaptic challenges on synaptic transmission. © 2004 Wiley‐Liss, Inc.
Progressive cognitive impairment and anxiety induction in the absence of plaque deposition in C57BL/6 inbred mice expressing transgenic amyloid precursor protein
Authors: Lee Kang‐Woo , Lee Si Hyoung , Kim Hyuck , Song Jin‐Sook , Yang Sung‐Don , Paik Sang Gi , Han Pyung‐Lim
Published: April 2004

Numerous transgenic mouse models for Alzheimer's disease (AD) have been generated to recapitulate the histological pathogenesis and behavioral phenotypes of AD brain. However, none of the existing models exhibits the full spectrum of AD symptoms, nor have all of the traits mimicked by the developed animal models been successfully represented within a single mouse line, indicating that the development of transgenic lines showing new features of the AD‐like brain should be explored. Here we report on a transgenic mouse line, named Tg‐APP (Sw, V717F)/B6, that expresses the human amyloid precursor protein (APP) containing the Swedish and the V717F Indiana mutations in the brains of inbred C57BL/6 mice, designed to eliminate the potential phenotypic variations attributed to the compound genetic backgrounds adopted in most AD mouse models. The Tg‐APP (Sw, V717F)/B6 mice expressed the transgene transcript, in the heterozygote state, at a level of 2.6 ± 0.1 fold higher than that of endogenous mouse APP. However, no Aβ‐plaque deposition was produced in the brain of the Tg‐APP (Sw, V717F)/B6 mice up to 18 months of age. The Tg‐APP(Sw, V717F)/B6 mice at 13–15 months showed reduced expression of calbindin and c‐Fos in the brain. The Tg‐APP (Sw, V717F)/B6 mice at 11–14 months displayed decreased motor coordination, learning and memory deficits, and severely increased anxiety. These phenotypes were not observed in the Tg‐APP (Sw, V717F)/B6 mice at 5–7 months. Microarray analysis revealed altered expression, in the amygdala of the Tg‐APP (Sw, V717F)/B6 mice, of genes previously implicated in anxiety. Taken together, these results suggest that the transgenic APP, or its derivatives, produces the age‐dependent pathophysiology of the AD‐like brain and that the progressive cognitive impairment and anxiety induction can proceed in the absence of visible Aβ‐plaque deposition. © 2004 Wiley‐Liss, Inc.