bluuebunny/crossref_metadata_2025 huggingface dataset:
Different ω‐conotoxins mark the development of Swiss Webster mouse cortex suggesting N‐Type voltage sensitive calcium channel subtypes
Authors: Abbott J.R. , Litzinger M.J.
Published: April 2003

ω‐GVIA conotoxin has been used to mark presynaptic N‐type voltage sensitive calcium channels (VSCC).3,13,19,21–23 Litzinger et al.9 used ω‐conotoxin binding to describe a critical period of neurodevelopment in Swiss Webster mice between postnatal days (PND) 11 and 14, which appears to be important to the initiation of proper final development of the central nervous system. In this study, we compare how three different ω‐conotoxins (i.e. GVIA from Conus geographus, MVIIA from Conus magus, and RVIA from Conus radiatus) mark N‐type VSCC during this critical period in Swiss Webster mouse cortex. 125I‐GVIA was bound to Swiss Webster mouse cortex synaptosomal membrane fractions at postnatal days 8 and 14. 125I‐GVIA binding displacement curves were obtained by incubating membranes with increasing concentrations of unlabeled GVIA, MVIIA, and RVIA. Displacement curves and IC50 were calculated for each of these three ω‐conotoxins, and then compared. At PND 14, GVIA, MVIIA and RVIA were able to displace greater than 95% of 125I‐GVIA binding. At PND 8, however, MVIIA was only able to displace 83% of 125I‐GVIA binding, and RVIA was only able to block 84%. The IC150 does not appear to change significantly during this period of development for any of the ω‐conotoxins. The inability of MVIIA and RVIA to completely block 125I‐GVIA binding in pre‐critical period Swiss Webster cortex denotes an alteration in the composition of N‐type VSCC binding sites. With this data, we have suggested the presence of subtypes of the N‐type VSCC in the cortex of pre‐critical period Swiss Webster mouse.
Dexamethasone treatment specifically increases the basal proton conductance of rat liver mitochondria
Authors: Roussel Damien , Dumas Jean-François , Augeraud Antoine , Douay Olivier , Foussard Françoise , Malthiéry Yves , Simard Gilles , Ritz Patrick
Published: April 2003

We investigated the role that mitochondrial proton leak may play in the glucocorticoid‐induced hypermetabolic state. Sprague–Dawley rats were injected with dexamethasone over a period of 5 days. Liver mitochondria and gastrocnemius subsarcolemmal and intermyofibrillar mitochondria were isolated from dexamethasone‐treated, pair‐fed and control rats. Respiration and membrane potential were measured simultaneously using electrodes sensitive to oxygen and to the potential‐dependent probe triphenylmethylphosphonium, respectively. Five days of dexamethasone injection resulted in a marked increase in the basal proton conductance of liver mitochondria, but not in the muscle mitochondrial populations. This effect would have a modest impact on energy expenditure in rats.
The phosphorylation site in double helical amylopectin as investigated by a combined approach using chemical synthesis, crystallography and molecular modeling
Authors: Engelsen Søren Balling , Madsen Anders Østergaard , Blennow Andreas , Motawia Mohammed Saddik , Møller Birger Lindberg , Larsen Sine
Published: April 2003

The only known in planta substitution of starch is phosphorylation. Whereas the function of starch phosphorylation is poorly understood, phosphorylated starch possesses improved functionality in vitro. Molecular models of native crystalline starch are currently being developed and the starch phosphorylating enzyme has recently been discovered. Accordingly, it is desirable to obtain a more exact description of the molecular structures of phosphorylated starch. We have determined the crystal structure of methyl α‐D‐glucopyranoside 6‐O‐phosphate as its potassium salt which is thought to be the starch phosphate counterion in vivo. From this structure and previously known glucophosphate structures we describe the possible 6‐O‐phosphate geometries and through modeling extrapolate the results to the double helical structure of the crystalline part of amylopectin. The geometries of the existing crystal structures of 6‐O‐phosphate groups were found to belong to two main adiabatic valleys. One of these conformations could be fitted into the double helical amylopectin part without perturbing the double helical amylopectin structure and without creating steric problems for the hexagonal chain–chain packing.
Exploring the ability of chlorophyll b to bind to the CP43′ protein induced under iron deprivation in a mutant of Synechocystis PCC 6803 containing the cao gene
Authors: Duncan James , Bibby Thomas , Tanaka Ayumi , Barber James
Published: April 2003

Cyanobacteria, unlike plants and green algae, do not contain chlorophyll (Chl) b. This is because of the absence of the cao gene which encodes the enzyme that catalyses a two step oxygenation of chlorophyllide a to chlorophyllide b. Recently, however, the cao gene of higher plants was engineered into Synechocystis PCC 6803 leading to Chl b synthesis in this cyanobacterium [Satoh et al., J. Biol. Chem. 276 (2001) 4293–4297]. Here we use this same cao‐plus mutant to show that Chl b can bind to the CP43′ protein, expressed in cells exposed to low iron levels, which normally binds Chl a only. In so doing CP43′ is changed to a Chl a/Chl b‐binding protein and in this respect resembles the closely related Chl a/Chl b‐binding Pcb protein of prochlorophytes (green oxyphotobacteria). The results emphasise the possibility of using an in vitro system to elucidate factors which control the binding of these two different forms of chlorophylls to the six transmembrane helical light‐harvesting proteins of oxygenic photosynthetic organisms.
Synthesis of a photoaffinity labeling analogue of the inactivating peptide of the Shaker B potassium channel
Authors: Fernandez Asia M. , Molina Antonio , Encinar Jose A. , Gavilanes Francisco , López-Barneo José , Gonzalez-Ros Jose M.
Published: April 2003

A photoactivatable derivative of the inactivating peptide of the Shaker B potassium channel (ShB peptide) has been synthesized from ShB peptide containing an added cysteine residue at the peptide carboxy‐terminus and 1‐(p‐azidosalicylamido)‐4‐(iodoacetamido)butane. The peptide derivative restores rapid inactivation in the deletion mutant Shaker BΔ6–46 potassium channel in a manner indistinguishable from that of the wild‐type ShB peptide. Also, both peptides display similar conformational behavior when challenged in vitro by an artificial model target that partly imitates the properties of the putative receptor site for the inactivating peptide in the Shaker B potassium channel. Therefore, we conclude that both functionally and conformationally the photoreactive peptide derivative is an adequate analogue of the wild‐type ShB peptide, suitable for photoaffinity labeling of its binding site in the Shaker B potassium channel. Moreover, because the ShB peptide also serves as an efficient inactivating peptide for a large variety of other potassium channels, it appears that the photoreactive analogue may be useful to explore homologous sites in many different channel proteins.
Design and synthesis of heterotrimeric collagen peptides with a built‐in cystine‐knot Models for collagen catabolism by matrix‐metalloproteases
Authors: Ottl Johannes , Battistuta Roberto , Pieper Michael , Tschesche Harald , Bode Wolfram , Kühn Klaus , Moroder Luis
Published: April 2003

A heterotrimeric collagen peptide was designed and synthesized which contains the collagenase cleavage site () of type I collagen linked to a C‐terminal cystine‐knot, and N‐terminally extended with (Gly‐Pro‐Hyp)5 triplets for stabilization of the triple‐helical conformation. By employing a newly developed regioselective cysteine pairing strategy based exclusively on thiol disulfide exchange reactions, we succeeded in assembling in high yields and in a reproducible manner the triple‐stranded cystine peptide. While the single chains showed no tendency to self‐association into triple helices, the heterotrimer (α1α2α1′) was found to exhibit a typical collagen‐like CD spectrum at room temperature and a melting temperature (T

m
) of 33°C. This triple‐helical collagen‐like peptide is cleaved by the full‐length human neutrophil collagenase (MMP‐8) at a single locus fully confirming the correct raster of the heterotrimer. Its digestion proceeds at rates markedly higher than that of a single α1′ chain. In contrast, opposite digestion rates were measured with the catalytic Phe79‐MMP‐8 domain of HNC. Moreover, the full‐length enzyme exhibits K

m
values of 5 μM and 1 mM for the heterotrimer and the single α1′ chain, respectively, which compare well with those reported for collagen type I (∼ 1 μM), gelatine (∼ 10 μM) and for octapeptides of the cleavage sequence (≥1 mM). The high affinity of the MMP‐8 for the triple‐helical heterotrimer and the fast digestion of this collagenous peptide confirm the decisive role of the hemopexin domain in recognition and possibly, partial unfolding of collagen.
Induction of ASABF (Ascaris suum antibacterial factor)-type antimicrobial peptides by bacterial injection: novel members of ASABF in the nematode Ascaris suum
Authors: PILLAI Ajitha , UENO Satoshi , ZHANG Hong , KATO Yusuke
Published: April 2003

Recently, invertebrate models have been widely used for the study of innate immunity. Nematodes are novel potential candidates because of the experimental advantages of Caenorhabditis elegans. However, whether nematodes have active immune responses is still ambiguous. Previously, we reported ASABF (Ascaris suumantibacterial factor)-type antimicrobial peptides in the parasitic nematode Ascaris suum and the genetic model nematode C. elegans. Further screening of a cDNA library and an expressed-sequence-tag database search detected five novel members of ASABF (ASABF-β, -γ, -δ, -ε and -ζ) in A. suum. The transcripts for ASABF-α, -β, -γ, and -δ clearly increased in the body wall, and also in the intestine for ASABF-δ, 4 h after injection of heat-killed bacteria into the pseudocoelom (body cavity), suggesting that these peptides are inducible in the acute phase of immune response. These results also suggest that the nematodes can recognize bacteria in the pseudocoelomic fluid and evoke an active immune response.
Relation between the temperature gradient and concentration gradient in superfluid 3He–4He mixtures
Authors: Zadorozhko A. A. , Kalko T. V. , Rudavskii É. Ya. , Chagovets V. K. , Sheshin G. A.
Published: April 2003

The temperature and concentration gradients ∇T and ∇x created by a heat flow in a superfluid 3He–4He mixture with a concentration of 9.8% 3He are measured in the steady state in the temperature range T=70–500 mK. It is found that the ratio ∇x/∇T obtained in the experiment can be described on the basis of a dependence of the osmotic pressure on the temperature and concentration. The data are used to find the thermodiffusion ratio and, hence, the thermodiffusion coefficient of this mixture.
Antiferromagnetic resonance spectrum in LaMnO3
Authors: Krivoruchko V. N. , Prymak T. E.
Published: April 2003

The substantially noncollinear magnetic structure realized in LaMnO3 in an external magnetic field is investigated, and the frequency–field diagram of the magnetic eigenmodes of the system is obtained. It is shown that neglect of the Dzyaloshinskii interaction, a measure which a number of authors contend is justified because the corresponding constants of the spin Hamiltonian are small compared to the anisotropy, leads to an incorrect description of the dynamics of the system.
Quantum interferometry and spin–orbit effects in a heterostructure with a 2D hole gas in a Si0.2Ge0.8 quantum well
Authors: Andrievskiı̆ V. V. , Rozheshchenko A. Yu. , Komnik Yu. F. , Myronov M. , Mironov O. A. , Whall T. E.
Published: April 2003

The magnetic-field dependence (up to 110 kOe) of the resistance of Si0.7Ge0.3/Si0.2Ge0.8/Si0.7Ge0.3 with a 2D hole gas in a Si0.2Ge0.8 quantum well is measured in the temperature range 0.335–10 K and in a range of variation of the currents from 100 nA to 50 μA. Shubnikov–de Haas oscillations are observed in the region of high magnetic fields, and in the low-field region H⩽1 kOe a positive magnetoresistance is observed which gives way to a negative magnetoresistance as the field is increased. This peculiarity is explained by effects of weak localization of the 2D charge carriers under conditions when the spin–orbit scattering time τso is close to the inelastic scattering time τφ, and it is evidence of a splitting of the spin states under the influence of a perturbing potential due to the formation of a two-dimensional potential well (the Rashba mechanism). Analysis of the weak localization effects gave the values of the characteristic relaxation times as τφ=7.2T−1×10−12 s and τso=1.36×10−12 s. From these characteristics of the heterostructure studied, a value of Δ=2.97 meV was obtained for the spin splitting.
Low-temperature thermal expansion of pure and inert-gas-doped fullerite C60
Authors: Aleksandrovskii A. N. , Dolbin A. V. , Esel’son V. B. , Gavrilko V. G. , Manzhelii V. G. , Udovidchenko B. G. , Bakai A. S. , Gadd G. E. , Moricca S. , Sundqvist B.
Published: April 2003

The low-temperature (2–24 K) thermal expansion of pure (single-crystal and polycrystalline) C60 and polycrystalline C60 intercalated with He, Ne, Ar, and Kr is investigated using a high-resolution capacitance dilatometer. The investigation of the time dependence of the sample length variations ΔL(t) on heating by ΔT shows that the thermal expansion is determined by the sum of positive and negative contributions, which have different relaxation times. The negative thermal expansion usually prevails at helium temperatures. The positive expansion is connected with the phonon thermalization of the system. The negative expansion is caused by reorientation of the C60 molecules. It is assumed that the reorientation is of a quantum character. The inert gas impurities affect the reorientation of the C60 molecules very strongly, especially at liquid-helium temperatures. A temperature hysteresis of the thermal expansion coefficient of Kr– and He–C60 solutions is revealed. The hysteresis is attributed to orientational polymorphous transformation in these systems.
Dispersion relations for cubic crystals with noncentral interactions. Cryocrystals
Authors: Manzheliı̆ E. V.
Published: April 2003

A study is made of how the presence of noncentral interactions of molecules with their nearest and next-nearest neighbors in crystals with cubic symmetry affects the dispersion relations. For certain directions in simple cubic (sc) and body-centered cubic (bcc) crystals with nearest-neighbor interactions the vibrational frequency depends only on the value of the noncentral interaction. A relatively small noncentral interaction has an important influence on the dynamic characteristics of a face-centered cubic (fcc) crystal. Quantitative estimates are made for cryocrystals with bcc and fcc lattices.
High-confinement-mode edge stability of Alcator C-mod plasmas
Authors: Mossessian D. A. , Snyder P. , Hubbard A. , Hughes J. W. , Greenwald M. , LaBombard B. , Snipes J. A. , Wolfe S. , Wilson H.
Published: April 2003

For steady state high-confinement-mode (H-mode) operation, a relaxation mechanism is required to limit build-up of the edge gradient and impurity content. Alcator C-Mod [Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] sees two such mechanisms—EDA (enhanced D-alpha H mode) and grassy ELMs (edge localized modes), but not large type I ELMs. In EDA the edge relaxation is provided by an edge localized quasicoherent (QC) electromagnetic mode that exists at moderate pedestal temperature T<500 eV, high pedestal density, and high edge safety factor, q95>3.5, and does not limit the buildup of the edge pressure gradient. The q boundary of the operational space of the mode depends on plasma shape, with the q95 limit moving down with increasing plasma triangularity. At high edge pressure gradients and temperatures the mode is replaced by broadband fluctuations ( f<50 kHz) and small irregular ELMs are observed. Ideal MHD (magnetohydrodynamic) stability analysis that includes both pressure and current driven edge modes shows that the discharges where the QC mode is observed are stable. The ELMs are identified as medium n (10<n<50) coupled peeling/ballooning modes. The predicted stability boundary of the modes as a function of pedestal current and pressure gradient is reproduced in experimental observations. The measured dependence of the ELMs’ threshold and amplitude on plasma triangularity is consistent with the results of ideal MHD analysis performed with the linear stability code ELITE [Wilson et al., Phys. Plasmas 9, 1277 (2002)].
Dissipative solitary kinetic Alfvén wave and electron acceleration
Authors: Wu D. J.
Published: April 2003

Some recent studies of observations in situ by space satellites show that low frequency electromagnetic fluctuations in the auroral ionosphere and magnetosphere can often be identified as soliatry kinetic Alfvén waves (SKAWs), and further analyses of the data reveal clearly that electron collisional dissipation can considerably affect the structure and evolution of SKAWs. In this paper, a model of nonlinear kinetic Alfvén waves, called a dissipative SKAW (DSKAW), is presented, in which the effect of electron collisional dissipation has been taken into account. The results show that DSKAW can produce a local shock-like structure with a net parallel electric potential drop, in which the associated parallel electric field is primarily caused by nonlinear electron inertia. In particular, it is argued that DSKAW can accelerate electrons efficiently to the order of the local Alfvén velocity. This suggests that DSKAW can provide an efficient acceleration mechanism for energetic electrons, which can frequently be encountered in various space and cosmic plasma environments.
Photodissociation dynamics of the S2 state of CH3ONO: State distributions and alignment effects of the NO (X2Π) photofragment
Authors: Yin Hong-Ming , Sun Ju-Long , Li Ya-Min , Han Ke-Li , He Guo-Zhong , Cong Shu-Lin
Published: April 2003

The photodissociation dynamics of methyl nitrite (CH3ONO) was studied using 266 nm laser photolysis, and NO photofragments X 2∏ ν″=0,1,2,3) were probed by single photon laser-induced fluorescence spectroscopy. The ground vibrational state of the NO was found to be most populated, and the rotational distributions of each vibrational level were quite hot. The alignment A0(2) between the electronic transition dipole moment involved in the absorption of the parent molecule and the rotational angular momentum J of the photofragment NO (v″=0) was measured. Polarization experiments showed that the rotational angular momentum of NO was aligned perpendicularly to the transition moment of the parent molecule. The negative A0(2) values and a preferential population of the ∏− doublet state revealed that the dissociation process has some characteristics of in-plane dissociation.
Nonequilibrium statistical mechanics of chemically reactive fluids
Authors: Dahler John S. , Qin Lihong
Published: April 2003

A formula is derived which expresses the rate of a chemical reaction (or relaxation process) as the convolution of a correlation integral and the isothermal fluctuation from equilibrium of the affinity of the reaction. Two examples are provided of the dynamic variables (reaction densities) that appear in this correlation integral. The first of these is the model of simple reactive spheres. The second incorporates mechanisms by which two colliding atoms can be transformed into a bound dimer and, conversely, by which dimer dissociation can occur.
Analytical equilibrium and interchange stability of single- and double-axis field-reversed configurations inside a cylindrical cavity
Authors: Parks P. B. , Schaffer M. J.
Published: April 2003

This paper reports on the interchange stability of a realistic analytical equilibrium solution of a field-reversed configuration (FRC) contained within a tight fitting cylindrical flux conserver with end walls, no external flux, and arbitrary elongation E. For E≫1, interchange stability is possible with ps/p0>7/12, where p0 is the peak pressure at the magnetic axis, and ps is the pressure at the separatrix/wall, a condition that appears to be compatible with high-pressure wall-confined, pulsed FRC implosions. Oblate configurations require somewhat less ps/p0 for stability. Analytical equilibria have been found for FRCs with two magnetic axes (doublets) with an internal figure-of-eight separatrix. A striking improvement in stability with respect to interchange modes was found in doublets: the private flux region (core) can be completely stabilized with zero separatrix pressure. This new finding suggests that doublet FRCs may be more relevant for steady-state fusion applications, which for good performance nominally require the absence of interchange turbulence as well as low edge-to-core pressure ratios.
High-pressure structure and equation of state study of nitrosonium nitrate from synchrotron x-ray diffraction
Authors: Song Yang , Somayazulu Maddury , Mao Ho-kwang , Hemley Russell J. , Herschbach Dudley R.
Published: April 2003

Several nitrogen oxide compounds transform to nitrosonium nitrate (NO+NO3−) under high pressure. In this study, NO+NO3− was synthesized by laser heating of N2O in a diamond-anvil cell and characterized by x-ray diffraction as a function of pressure at room temperature and low temperature. The unit-cell parameters were refined up to 32.2 GPa at 300 K, resulting in a denser structure than reported previously. The pressure-volume relations for NO+NO3− at 300 K were fitted to both Birch-Murnaghan and Vinet equations of state. The analysis indicates that NO+NO3− is denser than other nitrogen-oxygen assemblages, consistent with the conclusion that formation of the ionic species is driven by density rather than entropic effects. The low-temperature x-ray-diffraction data represent the first in situ measurements for this material, revealing consistent structural information and evolutions under pressure. These observations provide additional information on the stability relations and reaction diagram of N2O and NO+NO3−.
Resistive wall modes and error field amplification
Authors: Boozer Allen H.
Published: April 2003

Resistive wall modes and the rapid damping of plasma rotation by the amplification of magnetic field errors are related physical phenomena that affect the performance of the advanced tokamak and spherical torus plasma confinement devices. Elements of our understanding of these phenomena and the code that is used to design the major experimental facilities are based on the electrical circuit representation of the response of the plasma to perturbations. Although the circuit representation of the plasma may seem heuristic, this representation can be rigorously obtained using Maxwell’s equations and linearity for plasmas that evolve on a disparate time scale from that of external currents. These and related results are derived. In addition methods are given for finding the plasma information that the circuit representation requires using post-processors for codes that calculate perturbed plasma equilibria.
Role of the host matrix in the carrier recombination of InGaAsN alloys
Authors: Vinattieri A. , Alderighi D. , Zamfirescu M. , Colocci M. , Polimeni A. , Capizzi M. , Gollub D. , Fischer M. , Forchel A.
Published: April 2003

We present an experimental study of the carrier recombination dynamics in high-quality (InGa)(AsN)/GaAs and Ga(AsN)/GaAs quantum-well structures after picosecond excitation. A comparison among samples with and without nitrogen and with different In concentration shows that nonradiative channels originated in the host matrix [i.e., (InGa)As and GaAs] play a dominant role in the recombination dynamics of these heterostructures.
Self-organized titanium oxide nanodot arrays by electrochemical anodization
Authors: Chen Po-Lin , Kuo Cheng-Tzu , Tsai Tzeng-Guang , Wu Bo-Wei , Hsu Chiung-Chih , Pan Fu-Ming
Published: April 2003

Ordered nanodot arrays of titanium oxides were prepared from TiN/Al films on the silicon substrate by electrochemical anodization of a TiN layer using a nanoporous anodic aluminum oxide film as the template. The microstructure of the nanodot arrays was studied by transmission electron microscopy and scanning electron microscopy, and the chemical composition of nanodots was analyzed by electron energy loss spectroscopy. The as-prepared nanodots are basically composed of amorphous TiOx with a hexagonal arrangement and an average diameter of about 60 nm. Using this approach, it is expected that nanodot arrays of various oxide semiconductors can be achieved.
Memetics and innovation: profit through balanced meme management
Authors: Pech Richard J.
Published: April 2003

One of the major driving forces behind a firm’s success can be attributed to its meme management. Memes, analogous to the biological gene, are self‐replicating. They represent the knowledge, views, perceptions, and beliefs communicated from person to person. In a business context, memes can be used to manage market perceptions as well as managing the views a firm has of itself. If a firm focuses too persistently on replicating a specific product meme, and by its singularly unyielding focus fails to innovate, a competitor may obliterate it with a disruptive leap in product development. The former firm has failed because of its lack of flexibility and its inability to adapt to a product or market’s ongoing evolutionary process. Discusses the example of Rip Curl, the Australian surf‐wear giant, and how it has developed and managed three memes that are central to Rip Curl’s product success as well as the company’s innovative operations.
On the Three-Dimensional Finite Element Analysis of Dovetail Attachments
Authors: Beisheim J. R. , Sinclair G. B.
Published: April 2003

The stress analysis of dovetail attachments presents some challenges. These stem from the high stress gradients at the edges of contact. They also stem from the nonlinearities accompanying conforming contact. Even with two-dimensional analysis, obtaining converged peak stresses is not trivial. With three-dimensional analysis, convergence can be expected to be more difficult to achieve because of the added computational costs of refinement in three dimensions. To meet these challenges, this paper describes a submodeling procedure with finite elements. The submodeling approach features bicubic surface fits to displacements for submodel boundary conditions. The approach also features a means of verifying these boundary conditions have converged; this is crucial to obtaining accurate converged peak stresses. The approach is applied to a three-dimensional test piece used to simulate a dovetail attachment. This application leads to converged three-dimensional stresses. These stresses serve to quantify the sort of increases in contact stresses in attachments due to three-dimensional effects.
A REVIEW OF SYMMETRY ALGEBRAS OF QUANTUM MATRIX MODELS IN THE LARGE N LIMIT
Authors: LEE C.-W. H. , RAJEEV S. G.
Published: April 2003

This is a review article in which we will introduce, in a unifying fashion and with more intermediate steps in some difficult calculations, two infinite-dimensional Lie algebras of quantum matrix models, one for the open string sector and the other for the closed string sector. Physical observables of quantum matrix models in the large N limit can be expressed as elements of these Lie algebras. We will see that both algebras arise as quotient algebras of a larger Lie algebra. We will also discuss some properties of these Lie algebras not published elsewhere yet, and briefly review their relationship with well-known algebras like the Cuntz algebra, the Witt algebra and the Virasoro algebra. We will also review how the Yang–Mills theory, various low energy effective models of string theory, quantum gravity, string-bit models, and the quantum spin chain models can be formulated as quantum matrix models. Studying these algebras thus help us understand the common symmetry of these physical systems.
MAGNETOVISCOUS AND VISCOELASTIC EFFECTS IN FERROFLUIDS
Authors: ODENBACH S.
Published: April 2003

Suspensions of magnetic nanoparticles, commonly called ferrofluids, exhibit a broad variety of viscous effects induced by the action of magnetic fields. The related phenomena are in focus of research since about 30 years and have recently reached new dynamics due to the discovery of viscoelastic effects induced by magnetic fields. Here, effects due to the influence of magnetic fields on the rotation of single magnetic nanoparticles as well as cooperative phenomena and their importance for viscous effects in ferrofluids will be reviewed.
VISUALIZATION OF CORRELATION CASCADE IN SPATIOTEMPORAL CHAOS USING WAVELETS
Authors: NAKAO HIROYA , MISHIRO TSUYOSHI , YAMADA MICHIO
Published: April 2003

We propose a simple method to visualize spatiotemporal correlation between scales using wavelets, and apply it to two typical spatiotemporally chaotic systems, namely to coupled complex Ginzburg–Landau oscillators with diffusive interaction, and those with nonlocal interaction. Reflecting the difference between underlying dynamical processes, our method provides distinctive results for those two systems. Especially, for the nonlocally interacting case where the system exhibits fractal amplitude patterns and power-law spectrum, it clearly visualizes the dynamical cascade process of spatiotemporal correlation between scales.
IMPROVED DETECTION OF BIFURCATIONS IN LARGE NONLINEAR SYSTEMS VIA THE CONTINUATION OF INVARIANT SUBSPACES ALGORITHM
Authors: FRIEDMAN M. J.
Published: April 2003

The Continuation of Invariant Subspaces (CIS) algorithm [Demmel et al., 2001; Dieci & Friedman, 2001] produces a smooth orthogonal similarity transformation to block triangular form of a parameter dependent matrix A(s). The CIS algorithm is an adaptation of an iterative refinement technique for improving the accuracy of computed invariant subspaces.

On the basis of the CIS algorithm, new test functions are defined for an improved, more reliable detection of bifurcations in problems with simple bifurcations near multiple bifurcations, problems with multiple bifurcations, and problems with symmetries. Illustrative examples are given.
ADVANCED HISTOPATHOLOGICAL TECHNIQUES IN DIAGNOSIS OF THE MUSCLE AND TENDON ALTERATIONS
Authors: Józsa László G
Published: April 2003

In this mini review, I will attempt to briefly provide the microscopic possibilities in the diagnosis of muscle and tendon disorders based on more than 1000 muscle and 2000 tendon biopsies. The routine histological sections and light microscopy are still of value in the diagnosis of tendon and muscle pathology. The morphologic methods are time-consuming, and consequently should be done step by step. In diagnostic muscle pathology, enzyme histochemistry, histomorphometry, transmission and scanning electron microscopy, and immunohistochemistry are the most reliable methods, while in tendon pathology, they are polarized light microscopy, electron microscopy and immunohistochemistry. However, the histopathological methods can be used not only in the diagnosis of muscle and tendon disorders, but can also predict the physical condition of muscles, detect the healing and regenerating processes and the effectivity of drug administration.
1/f NOISE, INTERMITTENCY AND CLUSTERING POISON PROCESS
Authors: GRÜNEIS FERDINAND
Published: April 2003

This paper presents an extended mathematical base for the interpretation of cluster processes in introducing an intermittent stochastic process; this is characterized by clusters of events being separated by distinct breaks so-called intermissions. The spectral features of such an intermittent process are investigated for the case that either intermission δ or duration of cluster τc is power-law distributed like tz. Correspondingly, a spectral shape like 1/fb(z) is found; a pure 1/f shape (b=1) is obtained for z = -2. The most striking result is the dependence of exponent b(z) on quotient δ/τc: we obtain b≤2 for δ > τc and b≤ 1 for δ < τc. This behavior is explained by mutual time relations between clusters which cannot be neglected in case intermissions are small in comparison to duration of clusters (δ < τc). The conditions under which superimposed intermittent processes converge to the clustering Poisson process exhibiting 1/f noise are investigated. Possible applications are discussed for 1/f noise in neuronal spike trains, ionic channels, on-off intermittency and semiconductors.
Diurnal and Seasonal Variation of Stroke Incidence in Patients with Cardioembolic Stroke due to Atrial Fibrillation
Authors: Spengos Konstantinos , Vemmos Konstantinos , Tsivgoulis Georgios , Manios Efstathios , Zakopoulos Nikolaos , Mavrikakis Myron , Vassilopoulos Demitris
Published: April 2003

A seasonal variation with an incidence peak during the colder period of the year, as well as a circadian distribution with a single peak of stroke onset in the morning hours are described in various countries. Cardioembolic stroke seems to be the most frequent stroke subtype among Greek patients. Atrial fibrillation is identified as the most frequent cause of stroke. Analysis of the temporal pattern of symptom onset in a series of over 300 Greek patients with first-ever cardioembolic acute stroke due to atrial fibrillation revealed a circannual distribution with a peak during winter and a decline of stroke occurrence during summer. Analysis of the diurnal variation of symptom onset in this stroke subgroup showed a distribution with 2 incidence peaks between 08:00–10:00 and 16:00–18:00. A relation between the second, however lower, frequency peak and the traditional Greek habit of afternoon sleep (siesta) could be assumed. Possible clustering of cardiologic events in patients with atrial fibrillation, especially during the time interval after awakening from night and afternoon sleep, could be a plausible explanation, which certainly deserves to be further investigated.
Face-selective Activation in a Congenital Prosopagnosic Subject
Authors: Hasson Uri , Avidan Galia , Deouell Leon Y. , Bentin Shlomo , Malach Rafael
Published: April 2003

Congenital prosopagnosia is a severe impairment in face identification manifested from early childhood in the absence of any evident brain lesion. In this study, we used fMRI to compare the brain activity elicited by faces in a congenital prosopagnosic subject (YT) relative to a control group of 12 subjects in an attempt to shed more light on the nature of the brain mechanisms subserving face identification. The face-related activation pattern of YT in the ventral occipito-temporal cortex was similar to that observed in the control group on several parameters: anatomical location, activation profiles, and hemispheric laterality. In addition, using a modified vase – face illusion, we found that YT's brain activity in the face-related regions manifested global grouping processes. However, subtle differences in the degree of selectivity between objects and faces were observed in the lateral occipital cortex. These data suggest that face-related activation in the ventral occipito-temporal cortex, although necessary, might not be sufficient by itself for normal face identification.
Selected Polymorphs of CaCO3 Through Epitaxy with Inorganic Substrates Aligned with an Electric Field
Authors: Kim I.W. , Robertson R.E. , Zand R.
Published: April 2003

The epitaxial requirement for the selection of metastable arogonite among the polymorphs of calcium carbonate has been studied. Under calcite‐favorable conditions, the critical epitaxial strain with aragonite‐type inorganic substrates was found to be in the range 5–7 %. The Figure shows aragonite “fuzz” grown on SrCO3 crystals that were aligned and fractured perpendicular to the alignment axis.
A Multi‐Addressable Photochromic 1,2‐Dithienylcyclopentene‐Phenoxynaphthacenequinone Hybrid
Authors: Myles A.J. , Wigglesworth T.J. , Branda N.R.
Published: April 2003

Four unique states of the photochromic hybrid shown in the Figure can be independently addressed using light energy as the only input. This system benefits from the photochromic properties of the 1,2‐dithienylcyclopentene and phenoxynaphthacenequinone scaffolds and represents the first quaternary photo‐switch in which all states are thermally stable.
The role of thiol intermediates in 2‐mercaptobenzothiazole accelerated sulfur vulcanization of rubber model compounds
Authors: Van Der Horst M. , Hendrikse K. G. , Woolard C. D.
Published: April 2003

The model compound, 2,3‐dimethyl‐2‐butene (TME), was vulcanized using 2‐mercaptobenzothiazole (MBT) and sulfur. MBT was not consumed during the vulcanization reaction. The resultant crosslink products were bis(alkenyl) in nature. 2,3‐Dimethyl‐2‐buten‐1‐thiol (TME‐SH) was identified as being present in the vulcanization mixture by a postcolumn derivatization technique. The appearance of thiol was coincident with crosslinking. Polysulfanes (H2Sn) were formed on crosslinking. Studies of the reaction of TME‐SH and sulfur indicated a rapid reaction to form crosslink products and polysulfanes. No monosulfidic crosslink species were formed in these reactions. Closer investigation revealed the presence of small quantities of what appeared to be highly reactive polysulfidic thiols. This is the first time that such species have been identified in vulcanization systems. Consequently, MBT‐accelerated vulcanization of TME is proposed to occur via the reaction of MBT and S8 to form polysulfidic MBT, which then reacts with TME to form polysulfidic thiols. These thiols then rapidly react via a metathesis reaction pathway to provide crosslink products and polysulfanes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 47–54, 2003
Solid‐state polymerization of poly(ethylene terephthalate). II. Modeling study of the reaction kinetics and properties
Authors: Kim T. Y. , Jabarin S. A.
Published: April 2003

Comprehensive modeling studies were used to describe the kinetics of the solid‐state polymerization (SSP) of poly(ethylene terephthalate). The validity of the model was confirmed by the successful fitting of the experimental results for molecular weight increases, at temperatures ranging from 180 to 230°C and for times up to 12 h, with one fitting parameter. The changes in the concentrations for hydroxyl end groups ([OH]), carboxyl end groups ([COOH]), vinyl end groups, and terephthalic acid (TPA) were simulated with the model. During SSP, the contents of not only hydroxyl and carboxyl end groups but also vinyl ester end groups and TPA monomer were predicted to decrease as a function of the SSP time and temperature. The effects of the pellet size and the molar ratio of carboxyl end groups to hydroxyl end groups were also calculated. At an end‐group molar ratio ([COOH]/[OH]) of around 0.7, a maximum SSP rate was obtained. As the [COOH]/[OH] ratio increased, the contents of the vinyl end groups and TPA monomer were predicted to increase. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 213–227, 2003
Freisetzung gentechnisch veränderter Bakterien: Leuchtmarkierte Zellen von Sinorhizobium melilotiim Boden
Authors: Selbitschka Werner , Keller Mathias , Tebbe Christoph C. , Pühler Alfred
Published: April 2003

Im Rahmen des bislang einzigen Freilandexperiments mit gentechnisch veränderten Bakterien in Deutschland wurde die Entwicklung leuchtmarkierter Rhizobienstämme an zwei Freisetzungsstandorten in Niedersachsen und Bayern über einen Zeitraum von fünf beziehungsweise drei Jahren verfolgt. Als Modellorganismen für die gezielte Freisetzung in die Umwelt wurden Knöllchenbakterien eingesetzt, die in Symbiose mit der Nutzpflanze Luzerne zur biologischen Stickstofffixierung befähigt sind. Damit das Verhalten der Stämme in der Umwelt untersucht werden kann, wurden diese mit dem Leuchtgen des Glühwürmchens versehen, so dass die Stämme bei Anwesenheit des Substrats Luziferin Licht aussenden und damit zweifelsfrei identifiziert werden können. Gleichzeitig diente das Experiment zur Prüfung eines biologischen Eingrenzungskonzepts, das auf der Verwendung eines rekombinationsdefekten „Sicherheitsstammes”︁ basiert. Für beide Standorte wurde gezeigt, dass die freigesetzten Rhizobien nach längerer Zeit von der endogenen Population verdrängt werde. Die biologische Eingrenzung freigesetzter Bakterien durch Verwendung eines rekombinationsdefekten Stammes konnte unter Freilandbedingungen nicht demonstriert werden.
Advances in pig genomics and functional gene discovery
Authors: Rothschild Max F.
Published: April 2003

Advances in pig gene identification, mapping and functional analysis have continued to make rapid progress. The porcine genetic linkage map now has nearly 3000 loci, including several hundred genes, and is likely to expand considerably in the next few years, with many more genes and amplified fragment length polymorphism (AFLP) markers being added to the map. The physical genetic map is also growing rapidly and has over 3000 genes and markers. Several recent quantitative trait loci (QTL) scans and candidate gene analyses have identified important chromosomal regions and individual genes associated with traits of economic interest. The commercial pig industry is actively using this information and traditional performance information to improve pig production by marker‐assisted selection (MAS). Research to study the co‐expression of thousands of genes is now advancing and methods to combine these approaches to aid in gene discovery are under way. The pig's role in xenotransplantation and biomedical research makes the study of its genome important for the study of human disease. This review will briefly describe advances made, directions for future research and the implications for both the pig industry and human health. Copyright © 2003 John Wiley & Sons, Ltd.
Specialized hidden Markov model databases for microbial genomics
Authors: Gollery Martin
Published: April 2003

As hidden Markov models (HMMs) become increasingly more important in the analysis of biological sequences, so too have databases of HMMs expanded in size, number and importance. While the standard paradigm a short while ago was the analysis of one or a few sequences at a time, it has now become standard procedure to submit an entire microbial genome. In the future, it will be common to submit large groups of completed genomes to run simultaneously against a dozen public databases and any number of internally developed targets. This paper looks at some of the readily available HMM (or HMM‐like) algorithms and several publicly available HMM databases, and outlines methods by which the reader may develop custom HMM targets. Copyright © 2003 John Wiley & Sons, Ltd.
Mollaret's meningitis: Cytopathologic analysis of fourteen cases
Authors: Chan Theresa Y. , Parwani Anil V. , Levi Angelique Wolf , Ali Syed Z.
Published: April 2003

Mollaret's meningitis (MM) is a rare disease of benign nature characterized by recurrent episodes of aseptic meningitis. Cerebrospinal fluid (CSF) examination remains the sole diagnostic modality. Eighteen CSF samples from 14 patients were studied along with the clinical data. Specimens were prepared by cytocentrifugation and Millipore filtration and were stained with Diff‐Quik and Papanicolaou stains. Eight patients were men and six were women, with an age range of 17–74 yr (mean age 37 yr). Most common clinical presentation was recurrent episodes of headaches and photophobia followed by a sustained mild fever lasting 5–7 days. The CSF showed markedly increased cellularity with pleocytosis. The differential count showed predominant monocytosis ranging from 84% to 100% (mean 96). In our series, two patients had herpes simplex virus type 2 (HSV‐2) DNA detected by polymerase chain reaction (PCR) in the CSF. The monocytes were seen predominantly singly, but three cases showed a strong tendency to aggregate in small groups. Phenotypically, these cells had bean‐shaped bilobed nuclei as well as multiple deep nuclear clefts depicting the so‐called “footprint” appearance. In four cases, multiple blunt‐tipped cytoplasmic pseudopods were noted. Degenerated monocytes with the appearance of the so‐called “ghost cells” were noted in one‐half of the cases. Background cells were mostly small mature lymphocytes; however, one‐half of cases showed a significant amount of plasma cells and/or polymorphonuclear leukocytes (PMNs). Lysed blood with hemosiderin‐laden macrophages and numerous leptomeningeal cells were seen in two cases. CSF examination of MM presents a spectrum of cytomorphologic features. When interpreted in light of the appropriate clinical setting. the latter, although nonspecific, provides an accurate diagnosis. The differential diagnosis includes various degenerative, inflammatory/infectious, and lymphoproliferative disorders of the central nervous system. Diagn. Cytopathol. 2003;28:227–231. © 2003 Wiley‐Liss, Inc.
Papanicolaou Society of Cytopathology guidelines for educational notes, disclaimers, and similar comments on reports of cervical cytology specimens
Authors:   Papanicolaou Society of Cytopathology Practice Guidelines Task Force
Published: April 2003

Controversy exists regarding the need for and appropriate form of notes addended to cervical cytology reports. The Guidelines Task Force of the Papanicolaou Society of Cytopathology reviewed the pertinent literature and formulated a list of suggested guidelines to aid practicing cytopathologists in conforming to the National Cancer Institute Bethesda Workshop's consensus recommendations and to fill the requirements of the College of American Pathologists inspections. Diagn. Cytopathol. 2003;28:282–285. © 2003 Wiley‐Liss, Inc.
Fear of falling and postural control in Parkinson's disease
Authors: Adkin Allan L. , Frank James S. , Jog Mandar S.
Published: April 2003

This study investigated the relationship between fear of falling (FOF) and qualitative and quantitative postural control in Parkinson's disease (PD). Fifty‐eight nondemented PD patients were studied along with age‐matched healthy controls. The degree of FOF was estimated using the Activities‐specific Balance Confidence scale. Qualitative postural control was evaluated using a component of the Unified Parkinson Disease Rating Scale. Postural control was quantified, using centre of pressure measures obtained from a force plate, for eight standing balance tests of different challenges. The results showed that FOF was more evident for PD patients when compared with healthy individuals of similar age. Furthermore, FOF was significantly associated with a qualitative estimate of postural control in PD; individuals with PD who had a greater degree of posture impairment reported greater FOF. The results also showed that an estimate of FOF may help to explain quantitative postural instability in PD. FOF, when coupled with a qualitative estimate of postural control, was able to explain a greater amount of variation in quantitative balance performance for five of the eight balance tests. When considered independently, the qualitative measure of postural control, in general, could not well predict quantitative balance performance. The greater degree of FOF and its possible association with altered postural control suggests that FOF should be considered as an important, independent risk factor in the assessment and treatment of postural instability in patients with PD. © 2003 Movement Disorder Society
Dopamine D2 receptor TaqIA and TaqIB polymorphisms in Parkinson's disease
Authors: Tan Eng‐King , Tan Yanni , Chai Anthea , Tan Christopher , Shen Hui , Lum Sau‐Ying , Fook‐Cheong Stephanie M.C. , Teoh Mei‐Ling , Yih Yuan , Wong Meng‐Cheong , Zhao Yi
Published: April 2003

In a case control study, we examined the association of DRD2 Taq1A and Taq1B polymorphisms and risk of PD, and evaluated the strength of linkage disequilibrium of the polymorphisms. The Taq1A and Taq1B polymorphisms were in strong linkage disequilibrium. There was, however, no significant association of the two polymorphisms with PD. © 2003 Movement Disorder Society