bluuebunny/crossref_metadata_2025 huggingface dataset:
Transport processes in dilute gases over the whole range of Knudsen numbers. Part 1. General theory
Authors: Woods L. C.
Published: April 2006

The mean-free-path approach to kinetic theory, initiated by Maxwell, and largely abandoned after the Chapman-Enskog success with Boltzmann's equation, is revised and considerably extended in order to find expressions for the heat flux vector q and pressure tensor p, valid (it is hoped) for all Knudsen numbers, K. These expressions (equations (2.24) and (2.26)) are integrals taken over the whole volume of the fluid plus surface integrals taken over the solid boundaries. The one phenomenological element is the mean free path λ, which takes different values according to whether it is mass, momentum or energy that is transported by the molecules. The need for such an approach is evidenced by the existence of critical values of K, above which the Chapman-Enskog expansion in powers of K, truncated after a finite number of terms, fails to yield a solution. For example with the Burnett equations, which are correct to O(K2), the critical K in a shock wave is only 0·2 based upon the upstream λ.
Moving contact lines and rivulet instabilities. Part 1. The static rivulet
Authors: Davis Stephen H.
Published: April 2006

A rivulet is a narrow stream of liquid located on a solid surface and sharing a curved interface with the surrounding gas. Capillary instabilities are investigated by a linearized stability theory. The formulation is for small, static rivulets whose contact (common or three-phase) lines (i) are fixed, (ii) move but have fixed contact angles or (iii) move but have contact angles smooth functions of contact-line speeds. The linearized stability equations are converted to a disturbance kinetic-energy balance showing that the disturbance response exactly satisfies a damped linear harmonic-oscillator equation. The ‘damping coefficient’ contains the bulk viscous dissipation, the effect of slip along the solid and all dynamic effects that arise in contact-line condition (iii). The ‘spring constant’, whose sign determines stability or instability in the system, incorporates the interfacial area changes and is identical in cases (ii) and (iii). Thus, for small disturbances changes in contact angle with contact-line speed constitute a purely dissipative process. All the above results are independent of slip model at the liquid–solid interface as long as a certain integral inequality holds. Finally, sufficient conditions for stability are obtained in all cases (i), (ii) and (iii).
Decaying turbulence in neutral and stratified fluids
Authors: Dickey T. D. , Mellor G. L.
Published: April 2006

Decaying turbulence in neutral and stratified fluids has been studied experimentally for relatively high mesh Reynolds numbers and long time-histories. The neutral case indicates an initial period decay law, q2∝ t−1, through non-dimensional time
\[
W_gt/M \simeq 800
\]
which is considerably longer than previous measurements at the same mesh Reynolds number (Re = 48260). The stratified experiment resulted in a decay rate virtually identical to that of the neutral case through Wgt/M = 275. However the decay rate sharply decreased after this time when the field of turbulence was replaced by internal gravity waves. A critical Richardson number marks the transition from the turbulence to an internal gravity wave domain.
An improved slender-body theory for Stokes flow
Authors: Johnson Robert E.
Published: April 2006

The present study examines the flow past slender bodies possessing finite centre-line curvature in a viscous, incompressible fluid without any appreciable inertia effects. We consider slender bodies having arbitrary centre-line configurations, circular transverse cross-sections, and longitudinal cross-sections which are approximately elliptic close to the body ends (i.e. prolate-spheroidal body ends). The no-slip boundary condition on the body surface is satisfied, using a convenient stepwise procedure, to higher orders in the slenderness parameter (ε) than has previously been possible. In fact, the boundary condition is satisfied up to an error term of O(ε2) by distributing appropriate stokeslets, potential doublets, rotlets, sources, stresslets and quadrupoles on the body centre-line. The methods used here produce an integral equation valid along the entire body length, including the ends, whose solution determines the stokeslet strength or equivalently the force per unit length up to a term of O(ε2). The O(ε2) correction to the stokeslet strength is also found. The theory is used to examine the motion of a partial torus and a helix of finite length. For helical bodies comparisons are made between the present theory and the resistive-force theory using the force coefficients of Gray & Hancock and Lighthill. For the motion considered the Gray & Hancock force coefficients generally underestimate the force per unit length, whereas Lighthill's coefficients provide good agreement except in the vicinity of the body ends.
On laminar flow in curved semicircular ducts
Authors: Masliyah Jacob H.
Published: April 2006

Calculations of the flow field under laminar conditions in a helical semicircular duct have been made by numerically solving the Navier–Stokes equations. With the flat wall of the duct being the outer wall, the solution of the momentum equations for Dean numbers below 105 gave, for the secondary flow, twin counter-rotating vortices of Taylor–Goertler type. However, above a Dean number of Dn = 105, two solutions were possible. One solution was similar to that obtained for Dn < 105. The other solution revealed four vortices for the secondary flow. For Dn > 105, convergence to either flow pattern depended on the initial guess used in the numerical solution. Flow visualization confirmed the possibility of the presence of both types of secondary flow patterns.
Geostrophic fronts, bores, breaking and blocking waves
Authors: Stern Melvin E.
Published: April 2006

An undisturbed geostrophic density current flows along a vertical wall (the coast) with the free streamline (the front) located at a distanceLfrom the wall which is comparable to the Rossby radius of deformation. Finite amplitude perturbations with downstream wavelengths much larger thanLare discussed, and it is shown that the slope of the front in the horizontal plane increases with time. Some perturbations tend to ‘break’ seaward by developing large transverse velocities away from the coast. The temporal evolution of some perturbations is such as to completely ‘block’ the upstream flow, but the subsequent behaviour is beyond the scope of the theory. We also discuss the propagation of the nose of the intrusion when a density current debouches from a coastal source and then flows along the coastal boundary.
Vortex dynamics of the two-dimensional turbulent shear layer
Authors: Aref Hassan , Siggia Eric D.
Published: April 2006

The role of large vortex structures in the evolution of a two-dimensional shear layer is studied numerically. The motion of up to 4096 vortices is followed on a 256 × 256 grid using the cloud-in-cell algorithm. The scaling predictions of self-preservation theory are confirmed for low-order velocity correlations, although the existence of vortex structures produces large fluctuations even in a simulation of this size. The simple picture of the shear layer as a line of vortex blobs, that merge pairwise thus thickening the layer, is not seen. On the contrary, the layer seems to thicken by the scattering of vortex structures of roughly fixed size about the midline. The size of the vortex structures does not scale with the layer thickness. A study of the entrainment of a passive marker shows that flow visualization experiments may have overestimated the size of the vortex structures. It appears that the finite area vortices have time to equilibrate between mergings, and the consequences of applying equilibrium statistical mechanics to their internal structure are explored. A simple model is presented which demonstrates how the size and separation of vortex structures may lock into a fixed ratio. This is precisely the type of mechanism that is needed to produce simple scaling in a flow that has initially several distinct length scales. A number of consistency checks on the numerical results are performed. In particular, the evolution of the same vortex configuration on two grids of different size is compared. This test showed that, although errors on subgrid scales do propagate to small wavenumbers, the dominant wavenumber of vorticity cascades back ahead of the peak in the error spectrum.
The instantaneous velocity fields of coherent structures in coflowing jets and wakes
Authors: Perry A. E. , Lim T. T. , Chong M. S.
Published: April 2006

The instantaneous velocity vector fields which surround the coherent structures of Perry & Lim (1978) in coflowing jets and wakes have been successfully measured and related to the smoke patterns for Reynolds numbers of order 1000. By the use of critical point theory, a qualitative description of the three-dimensional flow field can be made and is applied to the simplest structures which were classified by Perry & Lim. From these results, the convection of smoke and vorticity from the source and the entrainment properties of the structures are discussed.
The return to isotropy of an homogeneous turbulence having been submitted to two successive plane strains
Authors: Gence J. N. , Mathieu J.
Published: April 2006

The authors consider an homogeneous non-isotropic turbulence which develops without mean velocity gradient so that it should return to isotropy. This turbulence has been obtained by application of two successive plane strains to a grid-generated turbulence, and this configuration has already been described in a preceding paper. It is shown in particular that the nonlinear effects make no significant contribution to the rotation of the principal axes of the Reynolds stress tensor. In the case of the return to isotropy, an important parameter connected with the turbulent energy distribution between three directions comes into play. In the present experiment it has a positive sign whereas in previous experiments this sign was negative. In particular, the authors conclude that, when this parameter is positive, the return to isotropy is slower than in the opposite case.
Long wavelength bifurcation of gravity waves on deep water
Authors: Saffman P. G.
Published: April 2006

Conditions are found for the appearance of non-uniform progressive waves of permanent form from a long-wave modulation of a finite-amplitude Stokes wave on deep water. The waveheight at which the modulated waves can occur is a very slowly decreasing function of the modulation wavelength for values up to 150 times the original wavelength. Some qualitative remarks are made about the problem of determining the stability of the new waves.
Nonlinear stern waves
Authors: Vanden-Broeck J.-M.
Published: April 2006

Steady two-dimensional potential flow past a semi-infinite flat-bottomed body is considered. This stern flow is assumed to separate tangentially from the body. Gravity waves of finite amplitude occur on the free surface. An exact relation between the amplitude of these waves and the Fronde number F is derived. It shows that these waves can exist only for F greater than the value F* = 2·23. This is slightly less than the value Fc = 2·26 at which breaking occurs. For F slightly larger than F*, the steepness is a multi-valued function of F, indicating the existence of more than one solution for these values of F. In addition, a numerical scheme based on an integro-differential equation formulation is derived to solve the problem in the fully nonlinear case. The shape of the free surface profile is computed for different values of F. As a check on the numerical results, they are shown to satisfy the exact relation between steepness and the Froude number.
Preliminary interpretation of Titan plasma interaction as observed by the Cassini Plasma Spectrometer: Comparisons with Voyager 1
Authors: Hartle R. E. , Sittler E. C. , Neubauer F. M. , Johnson R. E. , Smith H. T. , Crary F. , McComas D. J. , Young D. T. , Coates A. J. , Simpson D. , Bolton S. , Reisenfeld D. , Szego K. , Berthelier J. J. , Rymer A. , Vilppola J. , Steinberg J. T. , Andre N.
Published: April 2006

The Cassini Plasma Spectrometer (CAPS) instrument observed the plasma environment at Titan during the Cassini orbiter's TA encounter on October 26, 2004. Titan was in Saturn's magnetosphere during the Voyager 1 flyby and also during the TA encounter. CAPS measurements from this encounter are compared with measurements made by the Voyager 1 Plasma Science Instrument (PLS). The comparisons focus on the composition and nature of ambient and pickup ions. They lead to: A) the major ion components of Saturn's magnetosphere in the vicinity of Titan are H+, H2+ and O+/CH4+ ions; B) finite gyroradius effects are apparent in ambient O+ ions as the result of their absorption by Titan's extended atmosphere; C) the principal pickup ions are composed of H+, H2+, N+/CH2+, CH4+, and N2+; D) the pickup ions are in narrow energy ranges; and E) there is clear evidence of the slowing down of background ions due to pickup ion mass loading.
Homogeneous aerosol freezing in the tops of high‐altitude tropical cumulonimbus clouds
Authors: Jensen E. J. , Ackerman A. S.
Published: April 2006

Numerical simulations of deep, intense continental tropical convection indicate that when the cloud tops extend more than a few kilometers above the liquid water homogeneous freezing level, ice nucleation due to freezing of entrained aqueous sulfate aerosols generates large concentrations of small crystals (diameters less than ≃20 μm). The small crystals produced by aerosol freezing have the largest impact on cloud‐top ice concentration for convective clouds with strong updrafts but relatively low aerosol concentrations. An implication of this result is that cloud‐top ice concentrations in high anvil cirrus can be controlled primarily by updraft speeds in the tops of convective plumes and to a lesser extent by aerosol concentrations in the uppermost troposphere. While larger crystals precipitate out and sublimate in subsaturated air below, the population of small crystals can persist in the saturated uppermost troposphere for many hours, thereby prolonging the lifetime of remnants from anvil cirrus in the tropical tropopause layer.
Optical attenuation in defect-engineered silicon rib waveguides
Authors: Foster P. J. , Doylend J. K. , Mascher P. , Knights A. P. , Coleman P. G.
Published: April 2006

The excess optical attenuation at wavelengths around 1550nm induced by subamorphous dose ion implantation of silicon-on-insulator rib waveguides has been quantified. Optical attenuation is related to the introduction of lattice defects such as the silicon divacancy. After 2.8MeV Si+ implantation at a dose of 2.5×1014cm−2, the attenuation is greater than 1000dBcm−1. Using positron annihilation spectroscopy to determine the vacancy-type defect concentration, it is demonstrated that the absorption component of the excess attenuation can be predicted using a simple analytical expression. Additional losses are suggested to result from a defect induced change in the real part of the refractive index of the silicon waveguide. A processing strategy for ensuring that the absorption component dominates the excess attenuation is described, and it is shown that selective implantation of a relatively low dose of inert ions is an efficient method for the reduction of optical cross talk in silicon photonic circuits.
Ga adsorbate on (0001) GaN: In situ characterization with quadrupole mass spectrometry and reflection high-energy electron diffraction
Authors: Brown Jay S. , Koblmüller Gregor , Wu Feng , Averbeck Robert , Riechert Henning , Speck James S.
Published: April 2006

We have investigated the adsorption and subsequent desorption of Ga on (0001) GaN using simultaneous line-of-sight quadrupole mass spectrometry (QMS) and reflection high-energy electron diffraction (RHEED). The in situ QMS and RHEED desorption transient measurements demonstrate the Ga flux dependent accumulation of the theoretically predicted laterally contracted Ga bilayer [J. E. Northrup et al., Phys. Rev. B 61, 9932 (2000)] under conditions similar to those used during GaN growth by rf-plasma molecular beam epitaxy. We correlated bioscillatory RHEED desorption transients [C. Adelmann et al., J. Appl. Phys. 91, 9638 (2002)] to QMS-measured Ga-adsorbate coverage and found both to be consistent with layer-by-layer desorption of the Ga-adsorbate bilayer. The QMS-measured steady-state Ga-adlayer coverage exhibited a continuous increase from 0 to 2.4 ML (monolayer) with respect to impinging Ga flux at substrate temperatures of 640–700°C. We observed an exponential dependence of the Ga flux corresponding to 1.0 ML Ga-adsorbate coverage on substrate temperature and we measured an apparent activation energy of 2.43±0.11eV and an attempt prefactor of 6.77×1012nm∕min (4.36×1011Hz) for this transition.
Enhanced magnetostrictive properties of Mn substituted cobalt ferrite Co1.2Fe1.8O4
Authors: Bhame Shekhar D. , Joy P. A.
Published: April 2006

The effect of substitution of Fe and Co by Mn on the magnetostrictive properties of the cobalt ferrite Co1.2Fe1.8O4 has been studied and compared. The studies on Co1.2−xMnxFe1.8O4 and Co1.2Fe1.8−xMnxO4 (0⩽x⩽0.4) showed a marked dependence of magnetostriction on the substitution of both Fe and Co by Mn. Higher magnetostriction is obtained for the substitution of Co by Mn whereas the magnetostriction is reduced substantially on the substitution of Fe by Mn. Higher magnetostriction at low magnetic fields and enhancement of the strain ratio have been observed for the substitution of Co by Mn.
Void-induced dissolution in molecular dynamics simulations of NaCl and water
Authors: Bahadur Ranjit , Russell Lynn M. , Alavi Saman , Martin Scot T. , Buseck Peter R.
Published: April 2006

To gain a better understanding of the interaction of water and NaCl at the surface during dissolution, we have used molecular dynamics to simulate the interface with two equal-sized slabs of solid NaCl and liquid water in contact. The introduction of voids in the bulk of the salt, as well as steps or pits on the surface of the NaCl slab results in a qualitative change of system structure, as defined by radial distribution functions (RDFs). As an example, the characteristic Na–Na RDF for the system changes from regularly spaced narrow peaks (corresponding to an ordered crystalline structure), to a broad primary and smaller secondary peak (corresponding to a disordered structure). The change is observed at computationally short time scales of 100ps, in contrast with a much longer time scale of 1μs expected for complete mixing in the absence of defects. The void fraction (which combines both bulk and surface defects) required to trigger dissolution varies between 15%–20% at 300K and 1atm, and has distinct characteristics for the physical breakdown of the crystal lattice. The void fraction required decreases with temperature. Sensitivity studies show a strong dependence of the critical void fraction on the quantity and distribution of voids on the surface, with systems containing a balanced number of surface defects and a rough surface showing a maximum tendency to dissolve. There is a moderate dependence on temperature, with a 5% decrease in required void fraction with a 100K increase in temperature, and a weak dependance on water potential model used, with the SPC, SPC/E, TIP4P, and RPOL models giving qualitatively identical results. The results were insensitive to the total quantity of water available for dissolution and the duration of the simulation.
Photoluminescence upconversion in GaInNP∕GaAs heterostructures grown by gas source molecular beam epitaxy
Authors: Izadifard M. , Bergman J. P. , Chen W. M. , Buyanova I. A. , Hong Y. G. , Tu C. W.
Published: April 2006

Properties of photoluminescence (PL) upconversion (PLU) in GaInNP∕GaAs heterostructures are studied in detail by employing a number of optical spectroscopies. Based on excitation power dependent and temperature dependent PL measurements, the upconverted PL from GaInNP under optical excitation below its band gap is attributed to radiative transitions involving spatially separated localized electron-hole pairs, which is of a similar origin as the near-band-gap emission detected under optical excitation above the GaInNP band gap. The PLU process is shown to be largely promoted by increasing N content in the GaInNP alloys, due to a N-induced change in the band alignment at the GaInNP∕GaAs heterointerface from the type I in the N-free structure to the type II in the samples with N compositions exceeding 0.5%. A possible mechanism for the energy upconversion is discussed in terms of two-step two-photon absorption. The photon recycling effect is shown to be important for the structures with N=1%.
Influence of capping layer on the current-induced magnetization switching in magnetic nanopillars
Authors: Yang T. , Hirohata A. , Kimura T. , Otani Y.
Published: April 2006

Taking into account the thermal effect, we verify that the strong spin relaxation in the capping layer of a magnetic nanopillar significantly affects the current-induced magnetization switching behavior by reducing the critical switching current density. Theoretical calculations reveal that increasing the spin relaxation in the capping layer enhances the spin-polarized current while suppresses the contribution of the spin accumulation to the magnetization switching. The results suggest that the spin-polarized current, rather than the spin accumulation, dominates the current-induced magnetization switching.
Density functionals from many-body perturbation theory: The band gap for semiconductors and insulators
Authors: Grüning Myrta , Marini Andrea , Rubio Angel
Published: April 2006

Theoretically the Kohn-Sham band gap differs from the exact quasiparticle energy gap by the derivative discontinuity of the exchange-correlation functional. In practice for semiconductors and insulators the band gap calculated within any local or semilocal density approximations underestimates severely the experimental energy gap. On the other hand, calculations with an “exact” exchange potential derived from many-body perturbation theory via the optimized effective potential suggest that improving the exchange-correlation potential approximation can yield a reasonable agreement between the Kohn-Sham band gap and the experimental gap. The results in this work show that this is not the case. In fact, we add to the exact exchange the correlation that corresponds to the dynamical (random phase approximation) screening in the GW approximation. This accurate exchange-correlation potential provides band structures similar to the local density approximation with the corresponding derivative discontinuity that contributes 30%–50% to the energy gap. Our self-consistent results confirm substantially the results for Si and other semiconductors obtained perturbatively [R. W. Godby et al., Phys. Rev. B 36, 6497 (1987)] and extend the conclusion to LiF and Ar, a wide-gap insulator and a noble-gas solid.
Thermal variation of dielectric permittivities and dipole moments of two mesogens: 4-propyl-paraethoxy-phenyl-cyclohexyl-carboxylate and 4-butyl-paraethoxy-phenyl-cyclohexyl-carboxylate
Authors: Chakraborty Saswati , Mukhopadhyay Anuradha
Published: April 2006

Two compounds of a homologous series, namely, 4-propyl-paraethoxy-phenyl-cyclohexyl-carboxylate and 4-butyl-paraethoxy-phenyl-cyclohexyl-carboxylate, exhibiting a liquid crystalline behavior over a temperature range of 30°C are considered. The thermal dependence of the effective molecular dipole moment μeff of these compounds in the mesophase (nematic) has been determined from dielectric studies conducted at frequencies of 10 and 100kHz. The temperature variation of the angle of inclination β of the dipole moment with the molecular long axis has also been evaluated for the two molecules. With a view to determine the nature of the molecular association in the mesophase, the molecular correlation factors have been estimated from measurements of dipole moments of the compounds in solution.
Current-induced switching in single ferromagenetic layer nanopillar junctions
Authors: Özyilmaz B. , Kent A. D.
Published: April 2006

Current-induced magnetization dynamics in asymmetric Cu∕Co∕Cu single magnetic layer nanopillars has been studied experimentally at room temperature and in low magnetic fields applied perpendicular to the thin film plane. In sub-100nm junctions produced using a nanostencil process a bistable state with two distinct resistance values is observed. Current sweeps at fixed applied fields reveal hysteretic and abrupt transitions between these two resistance states. The current induced resistance change is 0.5%, five times greater than the anisotropic magnetoresistance effect. We present an experimentally obtained low field phase diagram of current-induced magnetization dynamics in single ferromagnetic layer pillar junctions.
Low voltage complementary organic inverters
Authors: De Vusser Stijn , Steudel Soeren , Myny Kris , Genoe Jan , Heremans Paul
Published: April 2006

We have developed a method for integrating n- and p-type organic thin-film transistors (OTFTs) on the same substrate. An integrated shadow mask was used for the n- and p-type semiconductor patterning. The integrated shadow mask can be aligned with submicron accuracy relative to the OTFT substrate. This allows for the integration at transistor level of n- and p-type OTFTs on the same substrate. A complementary inverter was fabricated, showing excellent performance while operating at a supply voltage of 2V.
Seroprevalance and Identification of Influenza A Virus Infection from Migratory Wild Waterfowl in China (2004–2005)
Authors: Chen H.‐X. , Shen H.‐G. , Li X.‐L. , Zhou J.‐Y. , Hou Y.‐Q. , Guo J.‐Q. , Hu J.‐Q.
Published: April 2006

Outbreaks of a highly pathogenic avian influenza (H5N1) were reported in birds in more than eight Asian countries. We sought to identify the origin of this infection, and herein report the results of serological and virological monitoring of migrant wild waterfowl in mainland China. From a total of 493 serum samples, collected from 15 migratory wild waterfowl species for 9 months (from June 2004 to May 2005) in mainland China, we detected only low‐level antibodies against influenza subtypes H2, H9 and H10 in the relict gull, little egret, black‐crowned night heron, bar‐tailed godwit, whimbrel and the common greenshank. No virus was identified from the 1052 cloacal and oropharyngeal swabs except dead bar‐headed geese. These data show that the influenza type A virus subtypes H2–H13 did not circulate at detectable levels within the sampled population.
Evaluation of ‘partnership care model’ in the control of hypertension
Authors: Mohammadi Eesa , Abedi Heidar Ali , Jalali Farzad , Gofranipour Fazlolah , Kazemnejad Anoshirvan
Published: April 2006

One of the shared common goals of World Hypertension League (WHL) and World Health Organization (WHO) is the control of hypertension. Despite many local and international interventions, the goal has not been achieved. This study evaluated an intervention based on the partnership care model to control hypertension in a rural population in the north of Iran. The results showed that the intervention was effective in decreasing systolic and diastolic blood pressure and in increasing the rate of controlled hypertensives (based on criteria of WHO/WHL). The intervention also had positive effects on health‐related quality of life, body mass index, anxiety, high density lipoprotein level and compliance score. Based on these results, the partnership care model is effective in hypertension control and is recommended as a model to replace previous approaches in hypertension control.
Glaucoma prescribing trends in Australia and New Zealand
Authors: Carroll Stuart C , Gaskin Brent J , Goldberg Ivan , Danesh‐Meyer Helen V
Published: April 2006

Abstract

Purpose:  To summarize current practice styles and patterns associated with glaucoma management in ophthalmologists of Australia and New Zealand as derived from a survey.

Method:  A questionnaire was sent to all Australian and New Zealand ophthalmologists, which anonymously assessed demographic characteristics and prescribing patterns for each major class of glaucoma medication.

Results:  A total of 761 questionnaires were sent with a response rate of 51%. Of respondents 14% were glaucoma subspecialists. In 69%, the first‐line drug‐class of choice was a prostaglandin analogue. New Zealand ophthalmologists favoured beta‐blockers as their first‐line agent because of cost, government restrictions and familiarity. Most respondents stated ‘hypotensive efficacy’ as the most important factor in class choice. Alpha‐2‐agonists, carbonic anhydrase inhibitors and miotics were considered second‐line agents, because of side‐effects and lack of hypotensive potency.

Conclusions:  The choice of first‐line agent for the treatment of glaucoma differed between Australian and New Zealand ophthalmologists, in part as the result of government restriction of prostaglandin‐class drugs. Practice patterns seen in Australasia parallel the current evidence base reported in peer‐reviewed literature.
Cost‐benefits of reduced aphicide usage on dwarf hops susceptible and partially resistant to damson‐hop aphid
Authors: BARBER A , CAMPBELL C A M , CRANE H , DARBY P , LILLEY R
Published: April 2006

Soil‐applied imidacloprid at full (125 g a.i. ha−1) and half approved doses gave levels of control of damson‐hop aphid, (Phorodon humuli), similar to that provided by foliar spray(s) of tebufenpyrad on the aphid‐susceptible dwarf hop cvs First Gold and Herald. On those cultivars, aphid control was unreliable on plots treated with quarter dose imidacloprid and was generally no better than on untreated plants. Aphids were virtually eliminated from the leaves by the end of July each year in all treatments consistent with the action of natural enemies. Aphid contamination of cones reflected the numbers on foliage at flowering time, but varied widely between years. Yields and percentage α‐acids content of dried hops were unaffected by the numbers of aphids on leaves early in the season and in cones at harvest, but aphid contamination reduced the economic values of crops by as much as 80%. Few P. humuli colonised the partially aphid‐resistant breeding line 23/90/08 before their numbers were regulated and consistent with natural enemy activity. Yields, percentage α‐acids content, and commercial value of harvested cones were similar in all treatments on 23/90/08 whether or not plants were treated with aphicides. The commercial risks posed by P. humuli preclude substantial reductions in aphicide usage on aphid‐susceptible dwarf hop cultivars, but future cultivars expressing a similar level of partial resistance to aphids as 23/90/08 should not need treatment with aphicides.
CONSTRUCTING QUANTUM VERTEX ALGEBRAS
Authors: LI HAISHENG
Published: April 2006

This is a sequel to [23]. In this paper, we focus on the construction of quantum vertex algebras over ℂ, whose notion was formulated in [23] with Etingof and Kazhdan's notion of quantum vertex operator algebra (over ℂ[[h]]) as one of the main motivations. As one of the main steps in constructing quantum vertex algebras, we prove that every countable-dimensional nonlocal (namely, noncommutative) vertex algebra over ℂ, which either is irreducible or has a basis of PBW type, is nondegenerate in the sense of Etingof and Kazhdan. Using this result, we establish the nondegeneracy of better known vertex operator algebras and some newly constructed nonlocal vertex algebras. We construct a family of quantum vertex algebras closely related to Zamolodchikov–Faddeev algebras.
A HEURISTIC QUANTUM THEORY OF THE INTEGER QUANTUM HALL EFFECT
Authors: KRAMER TOBIAS
Published: April 2006

Contrary to common belief, the current emitted by a contact embedded in a two-dimensional electron gas (2DEG) is quantized in the presence of electric and magnetic fields. This observation suggests a simple, clearly defined model for the quantum current through a Hall device that does not invoke disorder or interactions as the cause of the integer quantum Hall effect (QHE), but is based on a proper quantization of the classical electron drift motion. The theory yields a quantitative description of the breakdown of the QHE at high current densities that is in agreement with experimental data. Furthermore, several of its key points are in line with recent findings of experiments that address the dependency of the QHE on the 2DEG bias voltage and results that are not easily explained within the framework of conventional QHE models.
Genes regulated by estrogen in breast tumor cells in vitro are similarly regulated in vivoin tumor xenografts and human breast tumors
Authors: Creighton Chad J , Cordero Kevin E , Larios Jose M , Miller Rebecca S , Johnson Michael D , Chinnaiyan Arul M , Lippman Marc E , Rae James M
Published: April 2006

Background

Estrogen plays a central role in breast cancer pathogenesis. Although many studies have characterized the estrogen regulation of genes using in vitro cell culture models by global mRNA expression profiling, it is not clear whether these genes are similarly regulated in vivo or how they might be coordinately expressed in primary human tumors.

Results

We generated DNA microarray-based gene expression profiles from three estrogen receptor α (ERα)-positive breast cancer cell lines stimulated by 17β-estradiol (E2) in vitro over a time course, as well as from MCF-7 cells grown as xenografts in ovariectomized athymic nude mice with E2 supplementation and after its withdrawal. When the patterns of genes regulated by E2 in vitro were compared to those obtained from xenografts, we found a remarkable overlap (over 40%) of genes regulated by E2 in both contexts. These patterns were compared to those obtained from published clinical data sets. We show that, as a group, E2-regulated genes from our preclinical models were co-expressed with ERα in a panel of ERα+ breast tumor mRNA profiles, when corrections were made for patient age, as well as with progesterone receptor. Furthermore, the E2-regulated genes were significantly enriched for transcriptional targets of the myc oncogene and were found to be coordinately expressed with Myc in human tumors.

Conclusion

Our results provide significant validation of a widely used in vitro model of estrogen signaling as being pathologically relevant to breast cancers in vivo.
Preparation and Properties of η3-Allyl(halo)tris(trimethylphosphine)ruthenium(II) Complexes and Their Derivatives
Authors: Maruyama Yooichiroh , Shimizu Isao , Yamamoto Akio
Published: April 2006

Oxidative addition of allyl halides to Ru(cod)(cot) (cod = 1,5-cyclooctadiene, cot = 1,3,5-cyclooctatriene) in the presence of trimethylphosphine at 50 °C in benzene gives Ru(η3-allyl)(PMe3)3X (X = Br, Cl), which reacted with PhCHO to yield homoallylic alcohols, and with CO to afford an η2-acyl complex, RuBr(CO)(PMe3)2(η2-COCH2CH=CH2), and an (η1-allyl)ruthenium(II) complex, RuBr(CO)2(PMe3)2(η1-allyl).
Luminescence Properties of Divalent Europium Complexes of Polymer Ligands Containing [2.2.2] and [2.2.1] Cryptand Units
Authors: Iwamura Ryo , Higashiyama Nobuyuki , Takemura Kazuki , Tsutsumi Shuji , Kimura Keiichi , Adachi Gin-ya
Published: April 2006

Divalent europium (Eu2+) complexes with polymer ligands containing 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane ([2.2.2] cryptand) and 4,7,13,16,21-pentaoxa-1,10-diazabicyclo[8.8.5]tricosane ([2.2.1] cryptand) have been synthesized. The complexes emitted ca. 450 nm luminescence by ultra violet excitation. A Eu2+-[2.2.2] cryptate-attaching polymer had high luminescence efficiency and its maximum relative emission intensity was ca. 19% with respect to an NBS standard, CaWO4:Pb.
Bifurcated Bridging Cyano Group and Network of Hydrogen-bonded Water Molecules in a Novel Framework Host Inclusion Compound Triaquacadmium(II) Tricyanocuprate(I)-Acetonitrile (1/1)
Authors: Nishikiori Shin-ichi , Iwamoto Toschitake
Published: April 2006

The dimeric structure unit of [Cu2(CN)6]4− in the title inclusion compound involves two bifurcated CN groups respectively linked to two Cu(I) at the C and a Cd(II) at the N to form the framework host accommodating the CH3CN whose orientation is regulated with the hydrogen bonds among the guest and the waters of coordination in the host.
Stereoselective Addition of Alcohol to Alkyne Catalyzed by Dicationic Platinum and Palladium Complexes
Authors: Kataoka Yasutaka , Matsumoto Osamu , Ohashi Masataka , Yamagata Tsuneaki , Tani Kazuhide
Published: April 2006

In the presence of the dicationic catalysts derived from PtCl2(ligand) or PdCl2(ligand) (ligand = 2PPh3, diphosphine) and excess AgPF6 addition of MeOH to dimethyl acetylenedicarboxylate smoothly proceeded under mild conditions to give dimethyl methoxyfumarate selectively. The dicationic platinum catalysts were more catalytically active for the addition reaction than the corresponding palladium catalysts.
Utilization of Me3SiSnBu3-F− in Organic Synthesis. Reaction of an Allyl Anion Generated from Me3SiSnBu3 and CsF
Authors: Kinoshita Atsushi , Mori Miwako
Published: April 2006

The intramolecular cyclization of an allyl halide having a carbonyl group proceeded smoothly via an allyl anion in the presence of Me3SiSnBu3 and CsF in DMF. The resultant products were converted into useful compounds for the synthesis of natural products.
Asymmetric Hydrolyses of 1,2-Diacetoxycyclohexanes by the Cultured Suspension Cells of Marchantia polymorpha
Authors: Gotoh Shisei , Aoki Masahiro , Iwaeda Tomoko , Izumi Shunsuke , Hirata Toshifumi
Published: April 2006

The enantioselectivity in the hydrolyses of cis- and trans-1,2-diacetoxycyclohexanes by the cultured suspension cells of Marchantia polymorpha was very high. The acetoxyl groups at the stereogenic center of (R)-configuration were preferentially hydrolyzed.
Structure Revision of Polypodoside A. Major Sweet Principle of Polypodium glycyrrhiza
Authors: Nishizawa Mugio , Yamada Hidetoshi , Yamaguchi Yukiko , Hatakeyama Susumi , Lee Ik-Soo , Kim Jinwoong , Kinghorn A Douglas
Published: April 2006

The aglycone stereochemistry of an intensely sweet saponin, polypodoside A isolated from the fern Polypodium glycyrrhiza, was revised from 22S, 25R, 26S to 22R, 25S, 26R based on a direct chemical correlation with a related sweet saponin, osladin.
Perfluoroalkylation of Benzene by 185 nm Photolysis of Perfluoroazooctane
Authors: Nakamura Takako , Yabe Akira
Published: April 2006

Perfluoroazooctane was photolyzed in benzene upon low pressure Hg lamp irradiation to generate perfluorooctyl radicals, which reacted with an excess of benzene to afford perfluorooctylbenzene. The investigation on the wavelength and light intensity dependence revealed that this photolysis proceeded effectively upon 185 nm irradiation by two photon absorption.
Aggregate Formation of Pyrene-1-Carboxylic Acid in an Ion-complexed Langmuir-Blodgett Film Induced by Contact with HCl Gas
Authors: Niidome Yasuro , Fujihira Masamichi
Published: April 2006

Ion-complexation between a cationic amphiphile and pyrene-1-carboxylate (PyCOO−) dispersed the PyCOO− anions homogeneously in a Langmuir-Blodgett monolayer film. By bringing the film into contact with HCl gas, formation of fluorescent spots in the monolayer was observed by fluorescence microscopy. With an atomic force microscope, the spots were found to be topographically much higher than the monolayer level, and concluded to be aggregates formed by lateral diffusion of neutralized pyrene-1-carboxylic acid (PyCOOH) molecules in the monolayer.
Facile and Practical Total Syntheses of (±)-Mukulol and (±)-Cembrene by Low-valent Titanium-induced Keto Ester Cyclization
Authors: Li Weidong , Li Ying , Li Yulin
Published: April 2006

A direct approach of low-valent titanium-induced intramolecular keto ester cyclization was first applied to the total syntheses of macrocyclic diterpenoids, by which (±)-mukulol and (±)-cembrene were synthesized from geranylacetone by a short and efficient route.
C-Terminal Sequencing of Peptides and Proteins by Successive Degradation with Heptafluorobutyric Anhydride Vapor
Authors: Nabuchi Yoshiaki , Yano Hiroyuki , Kamo Masaharu , Takamoto Keiji , Satake Kazuo , Tsugita Akira
Published: April 2006

A chemical C-terminal sequencing method of proteins, involving cyanogen bromide cleavage of proteins, selective isolation of the C-terminal peptide and the C-terminal successive degradation with heptafluorobutyric anhydride vapor is presented. FAB/MS analysis of the C-terminal truncated peptide mixture clearly indicated the C-terminal sequence of a protein.
Concentration of Copper(II) Ion in Water Using a Water-Soluble Chelating Polymer and a Microporous Hollow Fiber
Authors: Tomida Tahei , Inoue Tatsuya , Fujita Kazuhisa , Masuda Seizo
Published: April 2006

A new method using a water-soluble chelating polymer and a microporous hollow fiber was developed for concentration of copper(II) ion in water. The copper(II) ion recovered into a chelating polymer (polyacrylic acid) solution could be determined directly with ICP or UV-spectrophotometer. Cu(II) in a sample solution was calculated from the rate of concentration. It was demonstrated that this method was useful for concentration of Cu(II) existing in dilute solutions (1–1000 μg dm−3).
Combined Use of Diphenyltin Sulfide or Lawesson’s Reagent and Silver Perchlorate as Effective Catalyst Systems in Aldol Reaction
Authors: Mukaiyama Teruaki , Saito Katsuyuki , Kitagawa Hideo , Shimomura Naoyuki
Published: April 2006

Catalytic aldol reactions of several aldehydes with trimethylsilyl enol ethers are effectively performed by combined use of diphenyltin sulfide (Ph2Sn=S) and silver perchlorate (AgClO4) or Lawesson’s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) and silver perchlorate under mild conditions.
Preparation and Characterization of Rhodium C60 Complexes [Rh(acac)(L)2(C60)] (L = py, 4-Mepy, 3,5-Me2py)
Authors: Ishii Youichi , Hoshi Hidenori , Hamada Yasushi , Hidai Masanobu
Published: April 2006

A series of novel C60 rhodium complexes [Rh(acac)(L)2(η2-C60)] (L = pyridine, 4-methylpyridine, 3,5-dimethylpyridine) were prepared by the reaction of [Rh(acac)(C2H4)2] with C60 followed by treatment with pyridine or its derivatives. The molecular structure of [Rh(acac)(3,5-Me2py)2(η2-C60)]·C6H6 was determined by the X-ray crystallographic analysis.
Heteroannulation of α,β-Unsaturated Carbene Complexes. [3+2] Dipolar Cycloaddition of Methoxy(α,β-alkynyl)tungsten Carbene Complexes with 1,3-Thiazolium-4-olates
Authors: Jung Ill-Yun , Yoon Yong-Jin , Rhee Kyu Seo , Shin Gap Cheol , Shin Sung Chul
Published: April 2006

A novel [3+2] dipolar cycloaddition of methoxy(α,β-alkynyl)tungsten carbene complexes with 1,3-thiazolium-4-olates, synthetic equivalents of thiocarbonyl ylide affords methoxy(thienyl)tungsten carbene complexes or methoxy(pyridyl)tungsten carbene complexes depending on the electronic nature of a substituent at N-3 on the 1,3-thiazole nucleus.
Generation and ESR Spectrum of a Persistent and Oxygen-Insensitive Free Radical. 2,7-Di-t-butyl-1-pyrenoxy
Authors: Miura Yozo , Yamano Eiji , Miyazawa Akira , Tashiro Masashi
Published: April 2006

Oxidation of 2,7-di-t-butyl-1-hydroxypyrene yields persistent and oxygen-insensitive 2,7-di-t-butyl-1-pyrenoxy radical (2) with the following ESR parameters: (aH) 0.532, 0.449, 0.430, 0.389, 0.164, 0.110, and 0.095 mT (aH), and 2.0037 (g). Radical 2 is isolated as a diamagnetic dimer which, upon dissolution, dissociates into 2 at room temperature. The ΔH and ΔS values for the dimer−1 and −35 ± 15 J mol−1 K−1, respectively. The negative ΔS value is briefly discussed.2 radical equilibrium are determined to be 7.2 ± 2.0 kJ mol
Synthesis of (Z)-1,2-Dihalo-1-alkenes by the Reaction of (Z)-(β-Halovinyl)phenyliodonium Salts with n-Bu4NX or KX/CuX. Competitions between Nucleophilic Vinylic Substitutions and Aromatic Substitutions
Authors: Ochiai Masahito , Oshima Kunio , Masaki Yukio
Published: April 2006

Nucleophilic vinylic substitutions of (Z)-(β-halovinyl)phenyliodonium salts with tetrabutylammonium halides proceed in a stereoselective manner with retention of configuration yielding vicinal (Z)-vinyl dihalides. This reaction competes with nucleophilic aromatic substitutions. Similar competition was observed in the reactions with potassium halides/cuprous halides.
The Tectonic interaction between the Paramirim Aulacogen and the Araçuaí Belt, São Francisco craton region, Eastern Brazil
Authors: Cruz Simone C.P. , Alkmim Fernando F.
Published: April 2006

The Paramirim aulacogen, hosted in the northern part of the São Francisco craton, corresponds to two superimposed and partially inverted rifts of Paleo and Neoproterozoic ages. The Rio Pardo salient of the Araçuaí belt defines the local limit of the craton and interferes with the aulacogen structures. In order to understand the mechanism and timing of the tectonic interaction between these tectonic features during the inversion processes, a structural analysis was undertaken in the southern Paramirim aulacogen and along the Rio Pardo salient. The results obtained indicate that the Rio Pardo salient formed during an early stage of closure of the Neoproterozoic Macaúbas rift system and consequent initiation of the Araçuaí orogen. The orogenic front propagated further northwards into the craton, causing a first stage of inversion in the southern terminus of the aulacogen trough. Subsequently, the Paramirim aulacogen experienced the main stage of inversion, which led to the development of a NNW-oriented basement involved fold-thrust system. These fabric elements overprint the Rio Pardo salient, and the structures of both the first and second stages of inversion affect the Salitre Formation, the youngestNeoproterozoic unit of the area, clearly indicating a Late Neoproterozoic maximum age for all the inversion stages of the Paramirim aulacogen.
Crescimento e desenvolvimento da planta daninha capim-camalote
Authors: Carvalho Saul Jorge Pinto de , Moreira Murilo Sala , Nicolai Marcelo , López Ovejero Ramiro Fernando , Christoffoleti Pedro Jacob , Medeiros Daniel
Published: April 2006

O capim-camalote (Rottboelia exaltata L.f.) é uma planta daninha com rápida disseminação nas áreas canavieiras do Brasil, causando significativas perdas de produtividade na cultura. Assim, esta pesquisa teve por objetivo avaliar o crescimento, o desenvolvimento vegetativo e a capacidade reprodutiva do capim-camalote, como mecanismo de melhoria do manejo a ser adotado. O experimento foi desenvolvido em casa de vegetação da ESALQ/USP, entre julho e outubro de 2004, quando foram realizadas 14 avaliações periódicas de crescimento, determinando-se: massa fresca e seca (total, parte aérea e raízes), área foliar e fenologia das plantas. Realizou-se a contagem do número de rácemos florais de 16 plantas e do número de sementes de 100 rácemos após florescimento. Pôde-se observar um rápido crescimento inicial das plantas, de tal forma que o início do florescimento ocorreu aos 49 dias após a semeadura. No fim do ciclo, verificaram-se nas plantas valores próximos a 120 g, 25 g e 1.600 cm² de massa fresca total, massa seca total e área foliar, respectivamente. Na ocasião das contagens, as plantas haviam emitido, em média, o total de 163 rácemos com 12 sementes cada uma, o que corresponde a mais de 2.000 sementes por planta. Pelos resultados alcançados verifica-se elevada capacidade de crescimento e habilidade reprodutiva do capim-camalote, explicando as razões que fazem dessa planta daninha um novo problema em potencial para a agricultura brasileira.
Diagnóstico em educação em saúde: um modelo para analisar as relações entre atitudes e práticas na área da saúde pública
Authors: Candeias Nelly Martins Ferreira , Marcondes Ruth Sandoval
Published: April 2006

São abordados aspectos relativos à natureza das inconsistências entre atitudes e práticas em termos de teorias psicossociais. Com vistas a facilitar a fase do diagnóstico no planejamento em educação em saúde, apresenta-se um modelo para análise da situação em que se encontra o objeto da saúde pública.