bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative studies of autonomic function
Authors: Hilz Max J. , Dütsch Matthias
Published: June 2005

Dysfunction of the peripheral and central autonomic nervous system is common in many neurological and general medical diseases. The quantitative assessment of sympathetic and parasympathetic function is essential to confirm the diagnosis of autonomic failure, to provide the basis for follow‐up examinations, and potentially to monitor successful treatment. Various procedures have been described as useful tools to quantify autonomic dysfunction. The most important tests evaluate cardiovascular and sudomotor autonomic function. In this review, we therefore focus on standard tests of cardiovascular and sudomotor function such as heart‐rate variability at rest and during deep breathing, active standing, and the Valsalva maneuver, and on the sympathetic skin response. These tests are widely used for routine clinical evaluation in patients with peripheral neuropathies. Refined methods of studying heart‐rate variability, baroreflex testing, and detailed measures of sweat output are mostly used for research purposes. In this context, we describe the spectral analysis of slow modulation of heart rate or blood pressure, reflecting sympathetic and parasympathetic influences, and consider various approaches to baroreflex testing, the thermoregulatory sweat test, and the quantitative sudomotor axon reflex test. Finally, we discuss microneurography as a technique of direct recording of muscle sympathetic nerve activity. Muscle Nerve, 2005
Heat shock proteins and neuromuscular disease
Authors: Nishimura Robert N. , Sharp Frank R.
Published: June 2005

The heat shock proteins are families of proteins with known activities that include chaperoning nascent peptides within the cell and cytoprotection. Most work on the nervous system has related to the role of heat shock proteins in neuroprotection from either hypoxic‐ischemic or traumatic injury. The role of these proteins during normal physiological activity and injury is still under investigation. Heat shock proteins in neuromuscular disease have been investigated to some extent but were largely neglected until recently. The goal of this review is to summarize the evidence linking heat shock proteins with neuromuscular disease and to provide some insight into the roles or functions of these proteins in disease states. Muscle Nerve, 2005
Fracture toughness evaluation of adjacent flow weld line in polystyrene by the SENB method
Authors: Yamada Koji , Tomari Kiyotaka , Ishiaku Umaru Semo , Hamada Hiroyuki
Published: June 2005

Fracture toughness of adjacent flow weld lines, defined as weld lines that occur when two flow fronts meet and continue to flow together in the same direction (meld line or hot weld line), was evaluated by the single‐edge notched‐bend (SENB) method using three differently‐shaped obstructive pins. Although the fracture toughness varied depending upon the shapes of the pin, the values could be standardized as the distance from the meeting point of the two flow fronts flowing around the pin. The fracture toughness decreased drastically from the meeting point along the weld line and then slightly increased. These characteristic features could be explained by flow‐induced molecular orientation at the weld line interface. The molecules around the meeting point that were initially oriented parallel to the weld line due to fountain flow were able to relax, and then entanglement across the weld line interface developed because the flow stopped in the middle of the filling process, resulting in high fracture toughness. In contrast, the material at the downstream side of the weld line continued flowing during the filling process, being stretched along the flow direction. So, the molecular orientation at this area could not relax. In addition, the V‐notch shape, i.e., the depth and length at the surface of the weld line, which also varied depending on the shape of the obstacles, was considered to be identical when the meeting point was allowed to be a datum point. Thus, the meeting point was found to be a significant factor when the properties of weld lines are investigated. POLYM. ENG. SCI., 45:1059–1066, 2005. © 2005 Society of Plastics Engineers
The extremely flat torsional potential energy surface of oxalyl chloride
Authors: Kim Sunghwan , Wheeler Steven E. , DeYonker Nathan J. , Schaefer Henry F.
Published: June 2005

The conformational behavior of oxalyl chloride has been investigated using ab initio Hartree–Fock (HF) and second-order Møller–Plesset (MP2) perturbation theories, and the coupled-cluster singles and doubles method appended with a perturbative inclusion of connected triple excitations [CCSD(T)]. Correlation consistent polarized valence quadruple-ζ (cc-pVQZ) and quintuple-ζ (cc-pV5Z) basis sets were used in this research. At the cc-pVQZ and cc-pV5Z HF levels, there is no stationary point corresponding to a stable gauche conformer. On the other hand, at the cc-pVQZ and cc-pV5Z MP2 levels and with the cc-pVQZ CCSD(T) method, the gauche conformer of oxalyl chloride was found at OC-CO dihedral angles of 81.9°, 79.4°, and 83.4°, respectively. At the cc-pV5Z MP2 level, the energy barrier from trans to gauche was predicted to be 0.74kcalmol−1 and that from gauche to trans to be 0.09kcalmol−1. Thus, the potential-energy surface along the OC-CO torsional mode is exceedingly flat. The existence of the gauche conformation is mainly due to the minimization of steric repulsion.
A density-functional-theory study of atomic nitrogen abstraction from Si(100)-(2×1) by a gaseous O(P3) atom
Authors: Herrera-Morales Paulo E. , Weaver Jason F.
Published: June 2005

We have employed density-functional theory (DFT) to investigate the abstraction of a nitrogen atom from the Si(100)-(2×1) surface by a gas-phase O(P3) atom for different initial bonding configurations of nitrogen at the surface. For the N–Si(100) structures investigated, nitrogen abstraction by an O(P3) atom is predicted to be exothermic by at least 1.9eV. Abstraction in a single elementary step is found only for the interaction of an O(P3) atom with nitrogen bound in a coordinatively saturated configuration, and an energy barrier of 0.20eV is computed for this reaction. For nitrogen bound in coordinatively unsaturated configurations, abstraction is predicted to occur by precursor-mediated pathways in which the initial O-surface collision results in the formation of a N–O bond and the concomitant release of between 2.7 and 4.8eV of energy into the surface, depending on the initial N–Si(100) structure. This initial step produces different surface structures containing an adsorbed NO species, which can then undergo a series of elementary steps leading to NO desorption. Since the barriers for these steps are found to be less than 1eV in all cases, a significant excess of energy is available from initial N–O bond formation that could activate NO desorption within no more than a few vibrational periods after the initial gas-surface collision. Nitrogen abstraction by such a pathway is essentially an Eley–Rideal process since NO desorption occurs rapidly after the initial gas-surface collision, without the reactants thermally accommodating with the surface. These computational results indicate that nitrogen abstraction by gaseous O(P3) atoms should be facile, even at low surface temperatures, if nitrogen is bound to the Si(100) surface in coordinatively unsaturated configurations.
At the boundary between reduced density-matrix and density-functional theories
Authors: Percus J. K.
Published: June 2005

Here, we revisit the problem of finding the ground-state energy of an N-fermion fluid under an external field, with molecular structure as the ultimate target. Density-functional methods only have to deal with electron density, but require an empirical functional; reduced density-matrix methods involve a matrix on pair space and do give exact bounds, but require very complex linear programming to achieve their results. The polydensity representation that we introduce has the advantage of dealing only with densities, requires no empirical information, and also gives exact bounds; the major problem is that of accumulating and utilizing conditions on the densities that iteratively improve their realizability in the class of N-fermion systems. We indicate several directions along these lines and make some primitive applications.
Diffusive solvent dynamics in a polymer gel electrolyte studied by quasielastic neutron scattering
Authors: Andersson D. , Engberg D. , Swenson J. , Svanberg C. , Howells W. S. , Börjesson L.
Published: June 2005

A quasielastic neutron scattering study has been performed on a polymer gel electrolyte consisting of lithium perchlorate dissolved in ethylene carbonate/propylene carbonate and stabilized with poly(methyl methacrylate). The dynamics of the solvent, which is crucial for the ion conduction in this system, was probed using the hydrogen/deuterium contrast variation method with nondeuterated solvent and a deuterated polymer matrix. Two relaxation processes of the solvent were studied in the 10–400μeV range at different temperatures. From analysis of the momentum transfer dependence of the processes we conclude that the faster process (∼100μeV) is related to rotational diffusion of the solvent and the slower process (∼10μeV) to translational diffusion of the solvent. The translational diffusion is found to be similar to the diffusion in the corresponding liquid electrolyte at short distances, but geometrically constrained by the polymer matrix at distances beyond ∼5Å. The study indicates that the hindered diffusion of the solvent on a length scale of the polymer network interchain distance (∼5–20Å) is sufficient to explain the reduced macroscopic diffusivity and ion conductivity of the gel electrolyte compared to the liquid electrolyte.
Long-range electrostatic interactions in hybrid quantum and molecular mechanical dynamics using a lattice summation approach
Authors: Dehez François , Martins-Costa Marília T. C. , Rinaldi Daniel , Millot Claude
Published: June 2005

A method based on a lattice summation technique for treating long-range electrostatic interactions in hybrid quantum mechanics/molecular mechanics simulations is presented in this article. The quantum subsystem is studied at the semiempirical level, whereas the solvent is described by a two-body potential of molecular mechanics. Molecular dynamics simulations of a (quantum) chloride ion in (classical) water have been performed to test this technique. It is observed that the application of the lattice summations to solvent–solvent interactions as well as on solute–solvent ones has a significant effect on solvation energy and diffusion coefficient. Moreover, two schemes for the computation of the long-range contribution to the electrostatic interaction energy are investigated. The first one replaces the exact charge distribution of the quantum solute by a Mulliken charge distribution. The long-range electrostatic interactions are then calculated for this charge distribution that interacts with the solvent molecule charges. The second one is more accurate and involves a modified Fock operator containing long-range electron-charge interactions. It is shown here that both schemes lead to similar results, the method using Mulliken charges for the evaluation of long-range interactions being, however, much more computationally efficient.
Two secondary modes in decahydroisoquinoline: Which one is the true Johari Goldstein process?
Authors: Paluch M. , Pawlus S. , Hensel-Bielowka S. , Kaminska E. , Prevosto D. , Capaccioli S. , Rolla P. A. , Ngai K. L.
Published: June 2005

Broadband dielectric measurements were carried out at isobaric and isothermal conditions up to 1.75GPa for reconsidering the relaxation dynamics of decahydroisoquinoline, previously investigated by Richert et al. [R. Richert, K. Duvvuri, and L.-T. Duong, J. Chem. Phys. 118, 1828 (2003)] at atmospheric pressure. The relaxation time of the intense secondary relaxation τβ seems to be insensitive to applied pressure, contrary to the α-relaxation times τα. Moreover, the separation of the α- and β-relaxation times lacks correlation between shapes of the α-process and β-relaxation times, predicted by the coupling model [see for example, K. L. Ngai, J. Phys.: Condens. Matter 15, S1107 (2003)], suggesting that the β process is not a true Johari–Goldstein (JG) relaxation. From the other side, by performing measurements under favorable conditions, we are able to reveal a new secondary relaxation process, otherwise suppressed by the intense β process, and to determine the temperature dependence of its relaxation times, which is in agreement with that of the JG relaxation.
Monte Carlo orbit/full wave simulation of ion cyclotron resonance frequency wave damping on resonant ions in tokamaks
Authors: Choi M. , Chan V. S. , Pinsker R. I. , Chiu S. C. , Heidbrink W. W.
Published: June 2005

To investigate the experimentally observed interaction between beam ion species and fast Alfvén wave (FW), a Monte Carlo code, ORBIT-RF [V. S. Chan, S. C. Chiu, and Y. A. Omelchenko, Phys. Plasmas 9, 501 (2002)], which solves the time-dependent Hamiltonian guiding center drift equations, has been upgraded to incorporate a steady-state neutral beam ion slowing-down distribution, a quasilinear high harmonic radio frequency diffusion operator and the wave fields from the two-dimensional ion cyclotron resonance frequency full wave code (TORIC4) [M. Brambilla, Plasma Phys. Controlled Fusion 41, 1 (1999)]. Comparison of ORBIT-RF simulation of power absorption with fixed amplitudes of FW fields from TORIC4 power absorption calculation, which assumes Maxwellian plasma distributions, attains agreement within a factor of two. The experimentally measured enhanced neutron rate is reproduced to within 30% from ORBIT-RF simulation using a single dominant toroidal and poloidal wave number.
Non-Abelian conversion and quantization of nonscalar second-class constraints
Authors: Batalin I. , Grigoriev M. , Lyakhovich S.
Published: June 2005

We propose a general method for the deformation quantization of any second-class constrained system on a symplectic manifold. The constraints determining an arbitrary constraint surface are in general defined only locally and can be components of a section of a nontrivial vector bundle over the phase-space manifold. The covariance of the construction with respect to the change of the constraint basis is provided by introducing a connection in the “constraint bundle,” which becomes a key ingredient of the conversion procedure for the nonscalar constraints. Unlike in the case of scalar second-class constraints, no Abelian conversion is possible in general. Within the BRST framework, a systematic procedure is worked out for converting nonscalar second-class constraints into non-Abelian first-class ones. The BRST-extended system is quantized, yielding an explicitly covariant quantization of the original system. An important feature of second-class systems with nonscalar constraints is that the appropriately generalized Dirac bracket satisfies the Jacobi identity only on the constraint surface. At the quantum level, this results in a weakly associative star-product on the phase space.
Four-dimensional indefinite Kähler Osserman manifolds
Authors: García-Río Eduardo , Rakić Zoran , Vázquez-Abal M. E.
Published: June 2005

It is shown that a four-dimensional Kähler metric is pointwise Osserman if and only if it is either of constant holomorphic sectional curvature or a Ricci flat complex surface. Examples of Kähler Osserman metrics with nilpotent Jacobi operators of all possible degrees are given.
Effects of impurity seeding and charge non-neutrality on electromagnetic electron temperature gradient modes in a tokamak
Authors: Tangri Varun , Singh Raghvendra , Kaw Predhiman
Published: June 2005

A linear theory of toroidal electromagnetic electron temperature gradient (ETG) mode is reported. The effects such as Debye shielding, impurities, magnetic flutter perturbations δB⊥ and compressible parallel magnetic field perturbations δB‖ are included in a fluid model. An eigenvalue equation is derived and solved analytically in local and semilocal limits. In the nonlocal limit, the eigenvalue equations are solved numerically. A comparison is also made of the linear thresholds obtained from this simple fluid model with previous gyrokinetic simulations. It is shown that the simple fluid theory results compare well with the thresholds obtained from gyrokinetic simulations.
Electron transport of a quantum wire containing a finite-size impurity under terahertz electromagnetic-field illumination
Authors: Zhou Guanghui , Li Yuan , Cheng Fang , Liao Wenfu
Published: June 2005

We investigate theoretically the electron-transport properties for a semiconductor quantum wire containing a single finite-size attractive impurity under an external terahertz electromagnetic-field illumination in the ballistic limit. Within the effective-mass free-electron approximation, the scattering matrix for the system has been formulated by means of a time-dependent mode matching method. Some interesting properties of the electron transmission for the system have been shown through numerical examples. It is found that in the case of a relatively large field amplitude and a frequency resonant with that corresponding to the difference between the two lowest lateral energy levels in the impurity region, the field-induced intersubband transition dominates the process as it does in the absence of the impurity. Furthermore, there is a steplike structure on the transmission as a function of the incident electron energy. However, in the case of a small field amplitude and nonresonant frequencies, both multiple symmetry Breit-type resonance peaks and asymmetry Fano-type dip lines appear in the electron transmission dependence on the incident energy due to the presence of the impurity and the external field. Therefore, within a certain energy range the transmission as a function of the field frequency and∕or field amplitude shows a rich structure. Moreover, the transmission dependence on the strength and size of the impurity is also discussed. Our results suggest that the electron-transport properties of a quantum wire are affected by the interplay effects between the impurity and the applied field.
Ab initio intermolecular potential-energy surface and microwave spectra for the Ne–OCS complex
Authors: Zhu Hua , Zhou Yanzi , Xie Daiqian
Published: June 2005

An ab initio potential-energy surface for the Ne–OCS complex was calculated using the coupled-cluster singles and doubles with noniterative inclusion of connected triples [CCSD(T)] with a large basis set containing bond functions. The interaction energies were obtained by the supermolecular approach with the full counterpoise correction for the basis set superposition error. The CCSD(T) potential was found to have three minima corresponding to the T-shaped and the linear Ne–SCO and Ne–OCS structures. The two-dimensional discrete variable representation method was employed to calculate the rovibrational energy levels for five isotopomers Ne–OCS, Ne22–OCS, Ne–OCS34, Ne–OC13S, and Ne–O18CS. The calculated pure rotational transition frequencies for the vibrational ground state of the five isotopomers are in good agreement with the observed values. The corresponding microwave spectra show that the b-type transitions (ΔKa=±1) are significantly stronger than the a-type transitions (ΔKa=0).
Rotating magnetic quadrupole current drive for field-reversed configurations
Authors: Milroy Richard D. , Guo H. Y.
Published: June 2005

In the translation, confinement, and sustainment experiment [A. L. Hoffman, H. Y. Guo, J. T. Slough, S. J. Tobin, L. S. Schrank, W. A. Reass, and G. A. Wurden, Fusion Sci. Technol. 41, 92 (2002)], field-reversed configurations (FRCs) are created and sustained using a rotating magnetic field (RMF). The RMF is usually in the form of a rotating dipole, which in vacuum penetrates uniformly to the axis of symmetry. However, plasma conditions in the FRC normally adjust so that the RMF only partially penetrates the plasma column. We have investigated the possibility of using a rotating quadrupole rather than a rotating dipole magnetic field. The vacuum field from a quadrupole is proportional to radius and cannot penetrate to the axis of symmetry; however, this is not a disadvantage if the current drive is confined to the outer region of the FRC. It was found that the quadrupole drive efficiency is comparable to that of a dipole, but the rotating dipole is more effective at stabilizing the n=2 rotational instability. A strong internal oscillation in Bθ is often observed in FRCs sustained by a quadrupole field. The spectral content of the signals indicates that an internal n=1 magnetic structure forms and corotates with the electrons. Similar but much lower amplitude structures can form when a rotating dipole is employed (edge-driven mode).
Dynamics of poloidal flows in enhanced reverse shear bifurcation
Authors: Srinivasan R. , Avinash K.
Published: June 2005

A simple reduced enhanced reverse shear (RERS) model is constructed to study the dynamics of poloidal flows during the ERS transition. This model predicts that a reversal of poloidal flow shear occurs just prior to the transition, as seen in experiment [R. E. Bell et al., Phys. Rev. Lett. 81, 1429 (1998)]. This transition front propagates until the radial location where the safety factor (q) is minimum and becomes locked there due to insufficient input power to overcome the threshold requirement for the bifurcation. This study also reveals that there can be many routes to ERS transition depending upon various tunable parameters.
The initial rate of vapor-solid interaction and its application in the detection of vapor at ultra low concentrations
Authors: Chandra Dipankar , Frazier Jack R. , Ringo Jill , Aramayo Carlos E.
Published: June 2005

The initial interaction between mercury vapor and gold film surfaces was determined from the response of gold-coated piezoresistive silicon cantilevers maintained at a constant temperature. It was found that for low mercury vapor concentration the cantilever response, indicative of interaction strength, exhibits weak dependence on mercury concentration and that the interaction remains confined to the gold film surface, with no detectable alteration of either its solid surface or bulk properties. A Freundlich isotherm [H. Freundlich, Colloid and Capillary Chemistry (E.P. Dutton, New York, 1922)] can approximate several characteristics of this interaction. For high mercury vapor concentration, the interaction extends to the entire volume of the gold film and deviates strongly from a Freundlich isotherm dependence. The initial interaction rate decreases slowly with decreasing mercury vapor concentration as determined from the response rate of change of a piezoresistive cantilever at equilibrium with condensed mercury. The mercury concentration could be confirmed independently of this process down to 0.09 part per billion. With continued cooling of the condensed mercury source, the initial interaction rate continues to decrease slowly, indicating probable detection at concentrations ranging to less than 1 part per quadrillion, though no independent confirmation of the mercury partial pressure is possible in this range. The cantilever response also increases strongly with decreasing platform surface temperature. Similar results were obtained for the interaction of ethanol vapor and the surface of a positive photoresist layer coating on piezoresistive silicon cantilevers. These characteristics will permit the development of new sensors in detecting vapors at ultra low concentrations.
The State of d Electrons in Transition Metals
Authors: Herring Conyers
Published: June 2005

This paper gives a brief critique, in elementary language, of the principal types of theoretical pictures which have been advanced concerning the electronic states of transition metals, especially those of the irongroup. It also calls attention to the possibility that some of the properties of these metals can be correlated by the use of concepts which have an exact, not just approximate, meaning for a many-electron system. The Fermi surface is probably a concept of this type. Major conclusions are that in the iron group metalsthe 3d electrons ought not to differ radically from those in the free atoms either in number or in spatial distribution, and that in most, though perhaps not all, of these metals the 3d electrons, magnetic or nonmagnetic,have an itinerant behavior.
Instability of Magnetic Resonance in Single Crystal Spheres of Yttrium Iron Garnet
Authors: Masters Joseph I.
Published: June 2005

Instabilities in YIG spheres that exist above certain threshold power values of cw microwave field are studied using samples of about 14−12 mm diam, that have low power line widths of 1 oe or less. Whereas the characteristic behavior such as asymmetrical line shape, “jump” effect etc. is somewhat similar to that reported for disks, the phenomenon is generally different.

It has been determined that this instability, which can occur at cw power levels below the threshold for significant spin wave growth, is due entirely to the heating effect of resonance absorption upon the anisotropy energy of the crystal lattice. As a result, the instability is characterized by a threshold curve that follows both the extrema and symmetry of the anisotropy curve for a given orientation. A straightforward theoretical explanation based on familiar relationships is outlined which fits the instability threshold vsorientation curve. The temperature instability provides a technique for measuring the “g” factor that is believed to be more direct than previous methods.
Transmission Electron Diffraction of Alnico V
Authors: Kronenberg K. J.
Published: June 2005

By grinding, polishing, and etching it is possible to render Alnico V thin enough for transmission electron metallography. 80-kv electrons penetrated Alnico V metal confirming the two-phase structure found earlier with replica techniques. Transmission diffraction on Alnico V samples reveal the crystal structures of both phases. The development of one phase out of the other was studied on samples from Alnico V at various states of the usual heat treatment.
Long Term Magnetic Stability of Alnico and Barium Ferrite Magnets
Authors: Kronenberg K. J. , Bohlmann M. A.
Published: June 2005

Alnico and barium ferrite materials do not age at room temperature. The decreases in remanence, occurring with time, are adjustments by the magnet to its environment. Remanence adjustment proceeds with the logarithm of time and amounts to 2% or less one year after magnetization. Remanences in magnets with Hci > 2200 oe show no changes. Also, the smaller the irreversible susceptibility at the operating point, the more stable is remance. Remanences can be stabilized completely by preadjustment.

Alnico V magnets are more stable than similar Alnico III magnets, even when the Alnico V magnets operate at a higher susceptibility. Néel's theory suggests that the oriented material is more stable than the isotropic material because larger volumes are involved in each magnetization reversal. To explain relatively large domain-like regions of reversal, we have to assume that magnetic regions cooperate during the magnetization reversal.
Flux Reversal in Soft Ferromagnetics
Authors: Gyorgy E. M.
Published: June 2005

Many aspects of flux reversal in soft ferromagnetic materials may be interpreted in terms of three types of flux reversal processes. These three types are domain wall motion, nonuniform rotation, and uniform rotation. It has been shown that in general wall motion is the predominant mechanism for values of the applied magnetic field slightly in excess of the coercive field, that nonuniform rotation predominates for intermediate magnetic fields, and that uniform rotation predominates for large fields. The salient features of these three types of flux reversal are discussed and compared with experimental findings. Special emphasis is given to polycrystalline, square-looped ferrites, and thin Permalloy films. The importance of geometric effects is illustrated in a review of detailed models for the uniform and nonuniform rotational processes. Specific limitations of the existing models are discussed, and possibilities for future advances are briefly outlined.
Elastic Switching Properties of Some Square Loop Materials in Toroidal Structures
Authors: Seelbach W. C. , Kiseda J. R.
Published: June 2005

Elastic switching properties of some square loop materials are presented and the concept of an elasticswitching constant Sw(r) is introduced. The plot of applied “turn over” field strength vs the inverse of the drive width indicates that the inelastic switching constant for a given material is four to five times greater than the elastic switching constant Sw(r). The “turn over” field strength is defined to be that value of field strength at which inelastic switching just starts and therefore is considered to be the upper limiting field strength for elastic switching. To a first-order approximation, the ratio of Sw(r) to Sw is shown to be equal to the percentage of the total flux capacity of the core that can be switched in an elastic mode of operation. Sw(r) values for Molybdenum Permalloy ranged from 0.0374 oe-μsec for 18-mil tapes to 0.0913 oe-μsec for 12-mil tape.
High-Speed Ferrite Rotating Half-Wave Plate
Authors: Coale Franklin S.
Published: June 2005

A novel approach for constructing a ferrite rotating half-wave plate for use as a frequency translator or an amplitude modulated single sideband modulator is presented. This is accomplished through the use of a four-wire balanced transmission line for generating both the rotating microwave fields and the rotating low frequency magnetizing fields. The principles of operation of this type modulator should allow modulation frequencies in excess of 10 Mc/sec.

Eddy current losses, which usually limit the high frequency modulation of ferrite single sideband modulators are minimized by passing high currents down the wires of the four-wire transmission line to generate the magnetizing field at the modulation frequency. The magnetic fields which are developed are sufficient to cause 180° relative phase shift between the orthogonal microwavecomponents. The magnetizing fields are phased in quadrature so that a rotating magnetic field is developed whose speed of rotation is determined by the frequency of the magnetizing field. The resultant microwave frequency shift is twice the frequency of the magnetizing field due to the inherent action of the half-wave plate.

If the amplitude of the magnetizing field is varied, then the relative phase shift produced by magnetic birefringence is no longer 180° but may be some value between 0° and 180°. This in effect produces a frequency translated signal whose amplitude varies with the magnitude of the magnetizing field.
Effect of Directional Orientation on the Magnetic Properties of Cube-Oriented Magnetic Sheets
Authors: Foster K. , Kramer J. J.
Published: June 2005

An investigation of the effect of directional orientation on the dc magnetic properties of cube-oriented([001] (100) textured) 3% silicon iron sheets has been made. Induction values for a field of 10 oe (B10)followed the relationship B10 = Bs/(cosθ+sinθ)where Bs is the saturation induction and θ is the average angular deviation of the 〈100〉 direction from the rolling direction. A plot of B10 values as a function of the percent of grains with a 〈100〉 direction within 10°of the rolling direction showed that very good directional orientation is required to obtain high B10 values.
Characteristics of Supermendur at 500°C
Authors: Lauriente M. , Lynn G. E.
Published: June 2005

An anomalous transient effect in Supermendur material is dramatically displayed when the magnetic properties of toroidal tape cores of the material are measured at temperatures between 500 and 600°C on a constant current flux reset tester. This test is designed to simulate the action of a half-wave self-saturating magnetic amplifier. Normally a steady-state cyclic flux change is achieved within one cycle of the applied alternating magnetizing field. A transient lasting several minutes (equivalent to several thousand cycles of alternating field) was observed instead for this alloy. When measured at room temperature after exposure to extreme temperatures the magnetic properties are observed to be degraded from the properties measured at room temperature before exposure. No direct evidence has been found to show that these two phenomena are related since specimens exposed to temperatures insufficient to cause the transient were observed to sustain some degradation in room temperature properties. The contributions of various mechanisms were investigated by environmental control. The most probable causes of the degradation of properties after high temperature exposure were concluded to be oxidation and relaxation of oriented domains.
Intrinsic and Anneal-Induced Anisotropy in Cobalt-Substituted W-Type Hexagonal Oxides
Authors: Bickford L. R.
Published: June 2005

The intrinsic and anneal-induced anisotropy of cobalt-substituted hexagonal ferrous W compounds containing some vacancies in lattice sites normally occupied by metal ions were measured by the torque method. Six oriented polycrystalline samples, corresponding to y = 0.03, 0.06, 0.12, 0.24, 0.45, and 0.9 in the formula BaCoyFe17.9−yO27, and one single crystal of composition Ba0.27Sr0.73Co1.845Fe16.155O27, were investigated. The results confirm the prediction that the cobalt ions and vacancies would be located in the spinel portion of theW lattice and therefore respond to magnetic annealing in much the same way as in the ferrite system CoxFe3−xO4. The contribution per cobalt ion to the anneal-induced anisotropy constant Ku was found to be approximately the same in the two systems (ca 3×10−16 erg/cobalt ion for annealing at 100°C). Other points of comparison include the dependence on cobalt concentration of Ku and the relaxation times characterizing the annealing process, the activation energy and the variation of Ku with temperature of anneal.

The first-order intrinsic hexagonal anisotropy constant K1 becomes more negative with increasing cobaltconcentration reaching a value of −4.35×106 erg/cc at 27°C for the single crystal. The value of K3, the constant which determines the anisotropy in the basal plane, is much larger for this crystal than for any other hexagonal oxide reported so far (K3 = −1.22×104 erg/cc at 27°C and +1.35×105 erg/cc at −196°C). Two of the compositions (y = 0.45 and 0.9) have cones of easy magnetization at −196°C.
Anisotropy and Inversion in Permalloy Films
Authors: Smith D. O. , Huber E. E. , Cohen M. S. , Weiss G. P.
Published: June 2005

A phenomenological model of field-induced and oblique-incidence anisotropy in Permalloy films is proposed. It is assumed that the field-induced structure does not introduce any local spatial dispersion in the macroscopic magnetization M; the opposite is assumed for oblique-incidence structure. In addition it is assumed that the oblique-incidence dispersion is anisotropic, being least when M is perpendicular to the depositing beam.

Support for the model comes from anisotropies, found for oblique-incidence films only, in the following measurements: resonance line width, transmission of polarized light, and resistivity. A primary success of the model is the prediction of a correlation between anisotropy and inversion (Hw/Hk>1). Inverted films can be made by crossing the field-induced and oblique-incidence anisotropies at 90°. Such films exhibit a “locked”state in which opposite rotation of M in local regions occurs; this implies centers of spatial dispersion and provides the connection with oblique-incidence anisotropy.

A method of inducing anisotropy by means of a moving substrate is described. The assumption of local dispersion is shown to apply to this type of anisotropy also.

Finally, a guide to understanding the interdependence of Hk and Hw is given in terms of the anisotropy model: field-induced structure does not have any effect on Hw, while oblique-incidence structure can be a primary determinant for Hw.
Static and Dynamic Studies of Magnetization Distribution in Thin Films by Electron Microscopy
Authors: Fuller Harrison W. , Hale Murray E.
Published: June 2005

Several modes of operation of a transmission electron microscope are discussed which are useful for the observation of the magnetization distribution in thin films. Gross defocusing of the instrument provides great sensitivity to slow variations in static magnetization direction, while slight defocusing enables the measurement of rapid variations of magnetization at high resolution. The applications of electron microscopy to dynamic wall studies is discussed; this can be demonstrated by motion pictures. Some new ways of observing domains and walls at instrumental focus are described which utilize an opaque knife edge for intercepting a fraction of the deflected electron beam below the specimen.
Magnetic Properties of Manganese Copper Alloys
Authors: Street R.
Published: June 2005

The magnetic properties of the manganese-copper alloy system have been investigated by using a number of experimental techniques. Long range antiferromagnetic order occurs in alloys of high manganese concentration;the disappearance of ordering is associated with a face centered tetragonal → face centered cubic martensitic transformation. By extrapolation of the experimental results it is possible to derive the Néel temperature and magnetic moment of manganese ions in pure fct γ-manganese as approximately 390°K and 2.4±0.1 μB, respectively. At lower manganese concentrations, it is likely that short range antiferromagnetic ordering occurs and in addition at sufficiently low temperatures weak ferromagnetic behavior associated with high coercive force becomes apparent. These results and possible interpretations of them are discussed.
Classical Theory of Spin Configurations in the Cubic Spinel
Authors: Kaplan T. A.
Published: June 2005

It recently has been pointed out that the Yafet-Kittel triangular spin configurations do not minimize the classical Heisenberg exchange energy in the cubic spinel. A perturbation calculation for determining the ground configuration is described in the present paper. We consider only nearest neighbor A-B and B-Binteractions (JAB and JBB), one spin magnitude SA for the A sites, and one SB for the B sites. The method consists of first determining the largest value, y0, of y = JBBSB/JABSA, for which the Néel configuration is stable with respect to sufficiently small spin deviations. One then looks for solutions of the extremum equations as power series in y−y0(≥0), such that the spin deviations from the Néel configuration are small when y−y0 is small. The detailed calculations lead to the following conclusions: 1. Equilibrium configurations exist which have, simultaneously, nonzero angles between spins on the A sites and between those on the B sites. 2. The ground state in the cubic spinel will probably be a long-range-ordered canted-spin arrangement,for at least some finite range of y−y0. The significance of these conclusions in connection with experiments on MnCr2O4 and Mn3O4, and with Anderson's remarks concerning spin configurations in spinels, is discussed.
Switching Behavior of Low Remanence Ferrite
Authors: Hagedorn F. B. , Gyorgy E. M.
Published: June 2005

Switching studies have been made on a low remanence ferrite. By using a sampling oscilloscope with a response time less than 5 × 10−10 second, switching times shorter than 5 × 10−9 second have been measured. About half of the flux in this ferrite appears to switch by nonuniform rotation, but even in small fields the remaining flux switches substantially faster than would be expected on the basis of nonuniform rotational reversal. This observation is interpreted as further evidence of the existence of a ferrite flux reversal process in which switching is speeded up by an interaction between the magnetization and a demagnetizing field. In contrast to square loop ferrites, the threshold field for both processes in this low remanence ferrite is approximately zero.
Fibronectin controls cap-dependent translation through β1 integrin and eukaryotic initiation factors 4 and 2 coordinated pathways
Authors: Gorrini Chiara , Loreni Fabrizio , Gandin Valentina , Sala Leonardo A. , Sonenberg Nahum , Marchisio Pier Carlo , Biffo Stefano
Published: June 2005

Fibronectin (FN) is a major matrix protein involved in multiple processes. Little is known about how adhesion to FN affects the translational machinery. We show that in fibroblasts adhesion to FN triggers translation through the coordinated regulation of eukaryotic initiation factors (eIFs) 4F and 2 and is impaired by blocking β1 integrin engagement. FN-stimulated translation has unique properties: (
i
) it is highly sensitive to the inhibition of phosphatidylinositol 3-kinase (PI3K), but not to the inhibition of mammalian target of rapamycin, downstream of PI3K; (
ii
) there is no synergy between serum-stimulated translation and FN-dependent translation; (
iii
) FN-dependent translation, unlike growth factor-stimulated translation, does not lead to increased translocation of 5′ terminal oligopyrimidine tract mRNAs to polysomes; and (
iv
) cells devoid of attachment to matrix show an impairment of initiation of translation accompanied by phosphorylation of eIF2α, which cannot be reverted by active PI3K. These findings indicate that integrins may recruit the translational machinery in a unique way and that FN-dependent translation cannot be blocked by mammalian target of rapamycin inhibition.
Extreme spatial variability in marine picoplankton and its consequences for interpreting Eulerian time-series
Authors: Martin Adrian P , Zubkov Mikhail V , Burkill Peter H , Holland Ross J
Published: June 2005

A high-resolution mesoscale spatial survey of picoplankton in the Celtic Sea, using flow cytometry, reveals cell concentrations of
Synechococcus
spp. cyanobacteria and heterotrophic bacteria that vary up to 50-fold over distances as short as 12 km. Furthermore, the range of abundances is comparable to that typically found on seasonal scales at a single location. Advection of such spatial variability through a time-series site would therefore constitute a major source of ‘error’. Consequently, attempts to model and to investigate the ecology of these globally important organisms
in situ
must take into account and quantify the hitherto ignored local spatial variability as a matter of necessity.
Continuum damage mechanics predictions of creep damage initiation and growth in ferritic steel weldments in a medium bore branched pipe under constant pressure at 590 °C using a five-material weld model
Authors: Hayhurst D.R , Hayhurst R.J , Vakili-Tahami F
Published: June 2005

The paper reports three-dimensional creep continuum damage mechanics (CDM) analyses of creep failure in a medium bore Cr–Mo–V low alloy ferritic steel welded branched-pressure vessel that has been tested under a constant pressure of 4 MPa, at a uniform temperature of 590 °C. The use of the CDM computer software
Damage XXX
to analyse the initiation and growth of creep damage and subsequent failure in the branch weld is reported for a five-material model that includes: parent, Type IV, refined heat affected zone (R-HAZ), coarse grained heat affected zone (CG-HAZ) and weld materials. The results of the analyses are presented for two cases: the first without the CG-HAZ; and, the second with the CG-HAZ included. For both cases, lifetimes are conservatively, yet accurately predicted. It is shown that it is necessary to use a Type IV thickness of 0.7 mm to accurately predict the failure location and mode. The results of metallographic examinations of a tested vessel and the predicted damage fields are in close accord. Failure is predicted to take place, by steam leakage, from the interior of the vessel, through the Type IV zone adjacent to the main pipe, connecting through the R-HAZ to the CG-HAZ, where leakage takes place at the weld toe in the crotch plane.
The COP9 signalosome regulates the Neurospora circadian clock by controlling the stability of the SCFFWD-1 complex
Authors: He Qun , Cheng Ping , He Qiyang , Liu Yi
Published: June 2005

The COP9 signalosome (CSN) promotes the function of SCF-type cullin-based ubiquitin ligase complexes in vivo. Paradoxically, removal of the Nedd8 modification of cullins by CSN inhibits the ubiquitin ligase activity of SCF complexes in vitro. Ubiquitination-mediated degradation of the Neurospora circadian clock protein FREQUENCY (FRQ) is critical for clock function. Ubiquitination of FRQ requires FWD-1, the substrate-recruiting subunit of an SCF complex. Here we show that disruption of a subunit of CSN (csn-2) impairs the degradation of FRQ and compromises its normal circadian expression. A FRQ-independent oscillator drives conidiation in the csn-2 mutant, resulting in a 2-d conidiation rhythm that persists in constant darkness (DD), constant light (LL), light-to-dark (LD) transitions, and temperature cycles. Strikingly, the levels of FWD-1 are drastically reduced in csn-2 mutant, explaining the impaired degradation of FRQ. Reduction of FWD-1 levels in the mutant requires its F-box, suggesting that its degradation is due to autoubiquitination. In addition, SKP-1 and CUL-1 of the SCFFWD-1 complex are also unstable in the mutant. Therefore, our results establish an important role of CSN in the circadian clock of Neurospora. Our findings also reconcile the CSN paradox and suggest that a major function of CSN is to maintain the stability of SCF ubiquitin ligases in vivo.
Review article: practical management of inflammatory bowel disease patients taking immunomodulators
Authors: SIEGEL C. A. , SANDS B. E.
Published: June 2005

Azathioprine, mercaptopurine, methotrexate, ciclosporin and tacrolimus all have their respective niches in the treatment of inflammatory bowel disease. These immunomodulators are potent and effective medications; however, they potentially have serious toxicity. To maximize benefit and minimize risk, clinicians must understand the mechanism of action, appropriate indications, range of toxicity and proper dosing of these medications. Furthermore, once initiating therapy, patients need to be monitored appropriately for evidence of efficacy and toxicity.

This review includes the rationale behind recommendations for the management and monitoring of patients using immunomodulators. For the purine antagonists – azathioprine and mercaptopurine – the evidence for utility of thiopurine methyltransferase testing and mercaptopurine metabolite monitoring is addressed. The roles of liver biopsy and screening for methylenetetrahydrofolate reductase mutations in patients taking methotrexate are reviewed. With appropriate monitoring, the calcineurin inhibitors – ciclosporin and tacrolimus – can be used safely and effectively.

Immunomodulators are important agents for the treatment of Crohn's disease and ulcerative colitis, and prescribing clinicians should be comfortable recognizing both their value and their limitations.