bluuebunny/crossref_metadata_2025 huggingface dataset:
Variational constraints on perturbed eigenvalues and their perturbation expansions
Authors: Silverman Jeremiah N. , van Leuven Jon C.
Published: February 2003

The variational principle, in the form of the minimum principle, the Hellmann–Feynman theorem, the curvature theorem, and the virial theorem, is used to derive a number of variational constraints on perturbed exact and variational eigenvalues and on their respective Rayleigh–Schrödinger (RS) and perturbational–variational (PV) perturbation expansions. These constraints are applicable to the lowest state of each symmetry of any system with a Hamiltonian of the form H=H0+H1λ, where H1 is positive or negative definite, and λ is a real perturbing parameter; in slightly weakened form the constraints are extended to all states of all atomic isoelectronic sequences. The interaction of the constraints severely limits the behavior of the eigenvalue and its first and second λ derivatives as the radius of convergence is approached from within along the real λ axis, and thus drastically restricts the possible form of the RS and PV perturbation expansions. In one application it is shown that for positive definite H1 the only possible geometric series expansion is an alternating one with even-order coefficients negative and odd-order coefficients positive; for negative definite H1 only the nonalternating geometric series with all coefficients negative is possible. Other summable series can be similarly investigated. In another application the constraints are used to study the determination of the radius of convergence of the expansions, and it is shown that violation of the constraints is a sufficient condition for ‖λ‖ equaling or exceeding the radius of convergence. It is argued that the existence of a finite radius of convergence due to a singularity on the real λ axis may be regarded as a mechanism by which the variational principle separates admissible from inadmissible eigenfunctions. Several examples of both exact and variational eigenfunctions and eigenvalues are presented to support these conclusions.
ClFx–H2 chemical lasers (x=1,3,5): vibration–rotation emission by HF from states with high rotational excitation
Authors: Krogh Ole D. , Pimentel George C.
Published: February 2003

Stimulated vibration–rotation emission by HF has been observed from states with high rotational excitation following flash photolysis of ClFx–H2–Ar mixtures (ClF, ClF3, ClF5). We report here only those observations connected with the very high rotational states J′?9 (e.g., up to v=1, J=20 and v=2, J=15) which are found to emit under grating-selective conditions. The patterns of emission indicate that direct population of the high J states by the vibrational pumping reaction(s) can be ruled out. Neither is the behavior consistent with Boltzman equilibration. The late threshold times and extended durations point to an energy transfer mechanism that involves rapid V→R deactivation with large ΔJ coupled with V→V up pumping in HF‡–HF‡ collisions to give a cumulative increase in rotational energy. Thus, V→V and V→R processes divert vibrational excitation into rotational excitation where it will tend to ’’pool’’ in high J states for which rotational equilibration is a slow process. These high J, P branch laser emissions reflect the role of rotational degrees of freedom in reaction dynamics and they furnish distinctive clues to energy processes that can influence significantly the efficiency and spectral composition of chemical laser emission.
Parametric energy level analysis of Ho3+: LaCl3
Authors: Crosswhite H. M. , Crosswhite Hannah , Edelstein Norman , Rajnak Katheryn
Published: February 2003

A 20-parameter least-squares fit to the levels of Ho3+:LaCl3 observed by Dieke and Pandey has been obtained. The results are in substantial agreement with their assignments and with the subsequent analysis of Rajnak and Krupke. A considerably more extensive atomic Hamiltonian was used, including operators for two- and three-particle electrostatic interactions, spin–orbit and spin–other-orbit magnetic interaction, two-particle pseudomagnetic configuration-mixing interactions, and single-particle crystal-field interactions. The fit of twenty parameters to 128 observed levels resulted in a mean error of 5.2 cm−1. The results are consistent with similar recent studies of Nd3+ and Pm3+ in the LaCl3 host.
Experimental evidence of chaotic states in the Belousov–Zhabotinskii reaction
Authors: Schmitz R. A. , Graziani K. R. , Hudson J. L.
Published: February 2003

Experimental results are reported which show strong evidence that the Belousov–Zhabotinskii reaction proceeds in an intrinsic chaotic (sustained time-dependent, nonperiodic) manner over a range of residence times in a continuous-flow stirred reactor. Outside of that range the experimental states reach a sustained periodic condition in some cases and a stable steady nonperiodic condition in others. A suggested theoretical basis for the observed behavior is discussed.
Structure and thermodynamics of the liquid–vapor interface
Authors: Weeks John D.
Published: February 2003

This paper is concerned with the effects that density fluctuations in different regions of a liquid–vapor interface have on the interfacial thermodynamic and structural properties. The total volume V is divided into a square array of columns whose width is the order of the bulk correlation length. The canonical partition function is written as a sum of constrained partition functions, each describing a system with a given number of particles in each column. Changes in the occupation number of each column (i.e., density fluctuations) are related to changes in position of the local Gibbs dividing surface, and the free energy of such distortions of the Gibbs surface is estimated using macroscopic ideas similar to those used in the capillary wave theory by Buff, Lovett, and Stillinger. Corrections to the interface tension as calculated for a single column with periodic boundary conditions are given. We make a self-consistent choice of the column width which yields a scaling law originally porposed by Widom. Fluctuations in position of the local Gibbs surfaces of widely separated columns cause the total interface width to depend on the system size and strength of an external field while the local width in a single column is proportional to the bulk correlation length. These fluctuations also cause the very long-ranged correlations parallel to the interface predicted by Wertheim. Both the singlet and the pair distributions functions are calculated. An extension of Wertheim’s analysis is given.
A scaling theory of solids under hydrostatic pressure
Authors: Munro R. G.
Published: February 2003

A scaling theory is proposed for solids under hydrostatic pressures which do not undergo structural phase transitions or symmetry distortions or for which distortions may be neglected. The theory is tested with two adjustable parameters by computing the linear frequency shifts (dν/dP) for the optical transitions 4A2(F) →2E, 2T2, 4T2(F), 4T1(F), 2T1 of Cr3+ ions in Al2O3. These results are further applied to Al2O3:Ti3+, V3+ with no additional parameter adjustments. Good agreement is found with all the data, including occurrences of both red and blue shifts. A general discussion of impurity ions isoelectronic to Cr3+ in Al2O3 is given. The evolution of the scaling theory into an effective potential representation of the externally applied pressure is also indicated.
Nonlinear wave equations for chemical reactions with diffusion in multicomponent systems
Authors: Wilhelm H. E. , van der Werff T. J.
Published: February 2003

From the conservation equations for the particle densities and the momentum densities of an arbitrary number of chemically reacting components, coupled, nonlinear wave equations are derived for the particle densities which describe the spatial and temporal change of each species as a result of reactions and diffusion. The coupled steady-state equations are reduced to a nonlinear reaction–diffusion equation for one component and linear Laplace equations for the other components. As applications, the dynamics of (i) fast reactive waves propagating with thermal speed, (ii) slow chemical waves propagating at infrasonic speeds, and (iii) the damping of the Lotka oscillations are analyzed within the frame of the hyperbolic theory. It is shown that the hyperbolic diffusion theory is free from the physical and mathematical deficiencies of the phenomenological (parabolic) diffusion theory.
A note on local exchange approximations in electronic collisions
Authors: Baille P. , Darewych J. W.
Published: February 2003

To assess the value of the free electron gas exchange approximation, based on Slater’s local approximation of exchange, we compare the test cases the results given by the exact formula with results given by modified formulae reviewed by Riley and Truhlar [J. Chem. Phys. 63, 2182 (1975)]. The exact formula is not superior and therefore we favor the semiclassical exchange approximation which performs well even for scattering lengths.
Resonant Raman study on vibrational–rotational structure of gaseous bromine
Authors: Chang Hua , Hwang Dah-Min
Published: February 2003

The resonant Raman spectrum of gaseous bromine excited by the 4880 Å radiation of an argon ion laser was carefully studied. The fundamental and eight overtones were investigated with high resolution. The S branches, which form broad bumps in the fundamental and the first overtone regions, develop into sharp band heads after Δv=2. The band heads of Q and S branches spread out and were well resolved in high order overtone regions. The data on the fundamental, the first, the second and the fifth overtones were presented to illustrate the above features. The measured peak positions were consistent with the calculated positions of the band heads of Q and S branches of the three isotopic molecules.
Longitudinal magnetic relaxation of 13C (or 15N) interacting with a strongly irradiated proton system
Authors: Brondeau J. , Canet D.
Published: February 2003

A general formalism concerning the relaxation of a low abundance spin 1/2 (13C or 15N for instance) interacting with a proton system is given. All calculations are done in the limit of extreme narrowing. It is demonstrated that, under conditions of complete proton decoupling, the recovery of 13C magnetization is exponential as long as the proton spin system does not possess any symmetry. Accordingly, the nuclear Overhauser enhancement has the same significance as for a simple AX system. This is because certain observables relative to proton spins vanish. This is no longer true when some symmetry occurs in the proton system, and the above mentioned observables have to be taken into account.
NMR study of micas. I. Distribution of Fe2+ ions on the octahedral sites
Authors: Sanz J. , Stone W. E. E.
Published: February 2003

Paramagnetic shifted NMR lines have been observed in the H+ spectra of a number of micas (having variable amounts of iron) as a function of frequency and orientation. The position of the shifted lines can be accounted for by a simple point dipolar field interaction. Certain conclusions concerning the occupation by ferrous ions of the two possible octahedral sites within the lattice can be drawn.
Theory of localized and nonlocalized adsorption of gases on heterogeneous surfaces
Authors: Oh Byung K. , Kim Shoon K.
Published: February 2003

A theory is developed for adsorption of gases on patchwise heterogeneous surfaces with the assumption of a discrete distribution of site energies. The lateral interactions between adatoms in the first layer are neglected, but those in the second layer are accounted by the cluster expansion theorem. The heterogeneity effect on the isotherm is studied via the renormalization of the first layer coverage. The representation of the first layer coverage in the form of a padé approximant is introduced to determine the distribution of site energies. There is established a set of inequalities for the coefficients of the Padé approximant, which is essential in the analysis of experimental data. The theory is successfully applied to the systems of gases adsorbed on rutile reported by Drain and Morrison. It is found that the rutile surface primarily consists of three kinds of patches, the relative extent of which is proportional to that of cleavage planes of rutile. The distribution of site energies is discussed in comparison with the distribution functions previously obtained by other authors. The cluster integrals for the second layer are determined. The theory is also applied to the systems of gases on porous silver given by Hobson.
M dependence of T1 and T2 for the inversion doublets of 15NH3
Authors: Hoke W. E. , Bauer D. R. , Flygare W. H.
Published: February 2003

The pressure dependence of T1 and T2 has been measured for the ΔM=0, ‖M‖ inversion transitions in the (J=2,K=2) and (J=3,K=3) rotational states of 15NH3. We find the T2 is not M dependent but that T1 is strongly M dependent. These results are successfully interpreted by using a modified version of the Anderson impact theory which shows an M2 contribution to T1. The consequences of these results to other experiments are also considered.
Magnetic susceptibility and high field Mössbauer effect studies of some spin triplet iron (IV) compounds
Authors: Oosterhuis W. T. , Dockum Bruce , Reiff William Michael
Published: February 2003

Mössbauer spectra of some spin triplet iron (IV) compounds with dithiocarbamate ligands have been observed in large magnetic fields at low temperatures. The magnetic and electric hyperfine interactions agree with the model put forth by Oosterhuis and Lang to explain the action of low symmetry crystal fields on a t42g electronic configuration. A trigonal distortion together with the spin–orbit interaction in a perturbation theory treatment is used as a model and gives the spin Hamiltonian parameters D, ?, ?, (efg), which simulate the data fairly well. The electric field gradient does vary with temperature while the paramagnetic interactions are essentially temperature independent in contrast to the behavior previously observed in tetragonal Fe(IV) arsine complexes. The temperature (1.6–300 K) and field dependence of the susceptibility of one of these salts Fe(diethyldithiocarbamate)3(BF4) has also been studied using the Faraday method giving a value of D=23.8 cm−1 from least square fitting consistent with D values required for reasonable fits of the temperature dependence of high field Mössbauer spectra.
On the origin of the dynamical differences on the diatomics-in-molecules and spline-fitted a
b i
n
i
t
i
o surfaces for the He+H2+ reaction
Authors: Sathyamurthy N. , Duff J. W. , Stroud C. , Raff L. M.
Published: February 2003

The dynamic behavior of the He→H+2→HeH++H reaction has been examined on a DIM and a cubic spline fit to the ab initio surface values of Brown and Hayes. Examination of the total integrated reaction probability and the variation of vibration–translation energy transfer as a function of initial H+2 vibration phase on these two surfaces, as well as on two composite spline-fitted surfaces, indicates that the origin of the dynamical differences on the DIM and SAI surfaces for the He+H+2 reaction resides primarily in differences in shape of the inner repulsive wall. For this reaction, this region is shown to be the most important topological feature of the surface. Vibrational excitation probabilities on the two surfaces at energies below reaction threshold are also presented and compared with the results of Chapman and Hayes on the DIM surface. In spite of the influence of a well, the trajectories are, on the average, direct and short-lived on the SAI surface. In contrast, they are indirect and long-lived on the DIM surface.
Reaction of Cl+ with D2
Authors: Jones C. A. , Sauers I. , Kaufman Joyce J. , Koski W. S.
Published: February 2003

The reaction of Cl+(3P,1D) with D2 was studied in the energy range 1–100 eV. The energy and angular distribution of the DCl+ ions were measured. The limiting values of the translational exoergicity indicate that in both reactions the ionic product was in the 2Π State. The reactions were found to proceed by direct mechanisms. The energy transfer processes involving inelastic and superelastic collisions of Cl+(3P) and Cl+(1D) with D2 and Ar were used to demonstrate the presence of 3P and 1D states in the Cl+ ion beam.
Bound hydroxyl in vitreous silica
Authors: Hartwig Charles M. , Rahn Larry A.
Published: February 2003

A weak line at 969 cm−1 (941 cm−1) in the Raman spectrum of vitreous silica is shown to be due to the Si–O stretch vibration of OH (OD) groups. A triatomic molecular model for this defect accurately predicts the observed deuterated frequencies for both the Si–O and the O–D stretch vibrations bound to network silicon atoms.
Vibrational and rotational relaxation of arsine in the solid state
Authors: Wilde Richard E. , Cohen Simon S.
Published: February 2003

Infrared spectra of AsH3 and AsD3, both neat and as point defects in Phase II, have been Fourier transformed to provide vibrational–relaxation and rotational–reorientation correlation functions. Kubo’s theory of line shape is used to show that, as the 32-K phase transition is approached from above, the system approaches the slow-modulation limit. It is concluded that rotational diffusion in arsine persists down to 32 K.
A study of calculated x-ray and electron diffraction scattering intensities by CO(1Σ+): Electron correlation effects
Authors: Epstein Joel , Stewart Robert F.
Published: February 2003

X-ray and high energy electron scattering intensities by CO(1Σ+) have been calculated for an MCSCF wavefunction. These results are compared to previous studies with an SCF wavefunction. It is found that both one-electron and two-electron parts of the scattering intensities undergo small, but comparable changes with the introduction of electron correlation by the MCSCF wavefunction. Generalized x-ray scattering factors for a [2‖2] expansion are also compared with a previous SCF result.
A comparison of the Becker–Döring and Lothe–Pound theories with exact cluster free energies from Monte Carlo simulations
Authors: Miyazaki J. , Pound G. M. , Abraham F. F. , Barker J. A.
Published: February 2003

Thermodynamic functions for small clusters of atoms interacting with 6:12 potentials are calculated using the classical Becker–Döring theory and the revised Lothe–Pound theory. Comparisons are made with the results of Monte Carlo studies on such clusters.
Unified treatment of intermolecular and thermodynamic potentials of polar fluids. II. Angle-dependent intermolecular potential
Authors: Linder Bruno , von Bergen Rafael , von Bergen Yolanda
Published: February 2003

A unified treatment is presented of intermolecular and thermodynamic potentials of polar fluids. The theory is specialized to the case in which the rotational and translational correlation times are comparable. It is shown that the latter condition leads naturally to an intermolecular potential which can be decomposed into repulsion, dispersion, electrostatic, and polarization terms, all of which are angle dependent. Expressions are developed for the fluid free energy in a perturbation series and the first few terms are considered in detail. Special attention is focused on the classical limiting form of the free energy for a system of axially-symmetric molecules. It is shown that the free energy expression is consistent with a Boltzmann distribution in which the intermolecular potential is, within the dipolar approximation, represented by a set of infinite order pair potentials, the leading terms of which reduce to the Stockmayer potential plus polarization terms. Comparison is made between our series expansion of the fluid free energy and other perturbation schemes.
Theoretical calculation of the structure and spectra of lithium oxides
Authors: Grow Dana T. , Pitzer Russell M.
Published: February 2003

The structures, properties, and spectra of the diatomic and triatomic lithium oxides LiO, LiOLi, LiLiO, and LiO2 have been computed using self-consistent field theory with large contracted Gaussian basis sets. In particular, equilibrium geometries, vibrational frequencies, electronic excitation energies, ionization potentials, and dipole moments have been calculated and compared with other results, both experimental and theoretical, where available. The existence of the LiLiO species is confirmed and a model calculation of the spin–orbit and Renner splittings in this molecule has been carried out. The properties and bonding in this series of molecules (including Li2O2) are summarized and compared.
NZO-3 Expression Causes Global Changes to Actin Cytoskeleton in Madin-Darby Canine Kidney Cells: Linking a Tight Junction Protein to Rho GTPases
Authors: Wittchen Erika S. , Haskins Julie , Stevenson Bruce R.
Published: February 2003

We previously demonstrated that exogenous expression of a truncated form of the tight junction protein ZO-3 affected junctional complex assembly and function. Current results indicate that this ZO-3 construct influences actin cytoskeleton dynamics more globally. We show that expression of the amino-terminal half of ZO-3 (NZO-3) in Madin-Darby canine kidney cells results in a decreased number of stress fibers and focal adhesions and causes an increased rate of cell migration in a wound healing assay. We also demonstrate that RhoA activity is reduced in NZO-3–expressing cells. We determined that ZO-3 interacts with p120 catenin and AF-6, proteins localized to the junctional complex and implicated in signaling pathways important for cytoskeleton regulation and cell motility. We also provide evidence that NZO-3 interacts directly with the C terminus of ZO-3, and we propose a model where altered interactions between ZO-3 and p120 catenin in NZO-3–expressing cells affect RhoA GTPase activity. This study reveals a potential link between ZO-3 and RhoA-related signaling events.
Mgm1p, a Dynamin-related GTPase, Is Essential for Fusion of the Mitochondrial Outer Membrane
Authors: Sesaki Hiromi , Southard Sheryl M. , Yaffe Michael P. , Jensen Robert E.
Published: February 2003

In Saccharomyces cerevisiae, mitochondrial fusion requires at least two outer membrane proteins, Fzo1p and Ugo1p. We provide direct evidence that the dynamin-related Mgm1 protein is also required for mitochondrial fusion. Like fzo1 and ugo1 mutants, cells disrupted for the MGM1 gene contain numerous mitochondrial fragments instead of the few long, tubular organelles seen in wild-type cells. Fragmentation of mitochondria in mgm1 mutants is rescued by disrupting DNM1, a gene required for mitochondrial division. In zygotes formed by mating mgm1 mutants, mitochondria do not fuse and mix their contents. Introducing mutations in the GTPase domain of Mgm1p completely block mitochondrial fusion. Furthermore, we show that mgm1 mutants fail to fuse both their mitochondrial outer and inner membranes. Electron microscopy demonstrates that although mgm1 mutants display aberrant mitochondrial inner membrane cristae, mgm1 dnm1 double mutants restore normal inner membrane structures. However, mgm1 dnm1 mutants remain defective in mitochondrial fusion, indicating that mitochondrial fusion requires Mgm1p regardless of the morphology of mitochondria. Finally, we find that Mgm1p, Fzo1p, and Ugo1p physically interact in the mitochondrial outer membrane. Our results raise the possibility that Mgm1p regulates fusion of the mitochondrial outer membrane through its interactions with Fzo1p and Ugo1p.
Mdm30 Is an F-Box Protein Required for Maintenance of Fusion-competent Mitochondria in Yeast
Authors: Fritz Stefan , Weinbach Nadja , Westermann Benedikt
Published: February 2003

Mitochondrial fusion and fission play important roles for mitochondrial morphology and function. We identified Mdm30 as a novel component required for maintenance of fusion-competent mitochondria in yeast. The Mdm30 sequence contains an F-box motif that is commonly found in subunits of Skp1-Cdc53-F-box protein ubiquitin ligases. A fraction of Mdm30 is associated with mitochondria. Cells lacking Mdm30 contain highly aggregated or fragmented mitochondria instead of the branched tubular network seen in wild-type cells. Δmdm30 cells lose mitochondrial DNA at elevated temperature and fail to fuse mitochondria in zygotes at all temperatures. These defects are rescued by deletion of DNM1, a gene encoding a component of the mitochondrial division machinery. The protein level of Fzo1, a key component of the mitochondrial fusion machinery, is regulated by Mdm30. Elevated Fzo1 levels in cells lacking Mdm30 or in cells overexpressing Fzo1 from a heterologous promoter induce mitochondrial aggregation in a similar manner. Our results suggest that Mdm30 controls mitochondrial shape by regulating the steady-state level of Fzo1 and point to a connection of the ubiquitin/26S proteasome system and mitochondria.
Opposing Roles of Integrin α6Aβ1 and Dystroglycan in Laminin-mediated Extracellular Signal-regulated Kinase Activation
Authors: Ferletta Maria , Kikkawa Yamato , Yu Hao , Talts Jan F. , Durbeej Madeleine , Sonnenberg Arnoud , Timpl Rupert , Campbell Kevin P. , Ekblom Peter , Genersch Elke
Published: February 2003

Laminin–integrin interactions can in some settings activate the extracellular signal-regulated kinases (ERKs) but the control mechanisms are poorly understood. Herein, we studied ERK activation in response to two laminins isoforms (-1 and -10/11) in two epithelial cell lines. Both cell lines expressed β1-containing integrins and dystroglycan but lacked integrin α6β4. Antibody perturbation assays showed that both cell lines bound to laminin-10/11 via the α3β1and α6β1 integrins. Although laminin-10/11 was a stronger adhesion complex than laminin-1 for both cell lines, both laminins activated ERK in only one of the two cell lines. The ERK activation was mediated by integrin α6β1 and not by α3β1 or dystroglycan. Instead, we found that dystroglycan-binding domains of both laminin-1 and -10/11 suppressed integrin α6β1-mediated ERK activation. Moreover, the responding cell line expressed the two integrin α6 splice variants, α6A and α6B, whereas the nonresponding cell line expressed only α6B. Furthermore, ERK activation was seen in cells transfected with the integrin α6A subunit, but not in α6B-transfected cells. We conclude that laminin-1 and -10/11 share the ability to induce ERK activation, that this is regulated by integrin α6Aβ1, and suggest a novel role for dystroglycan-binding laminin domains as suppressors of this activation.
Modeling biological systems using Dynetica—a simulator of dynamic networks
Authors: You Lingchong , Hoonlor Apirak , Yin John
Published: February 2003

Summary: We present Dynetica, a user-friendly simulator of dynamic networks for constructing, visualizing, and analyzing kinetic models of biological systems. In addition to generic reaction networks, Dynetica facilitates construction of models of genetic networks, where many reactions are gene expression and interactions among gene products. Further, it integrates the capability of conducting both deterministic and stochastic simulations.

Availability and supplementary information: Dynetica 1.0, example models, and the user's guide are available at http://www.its.caltech.edu/~you/Dynetica/Dynetica_page.htm

Contact: you@cheme.caltech.eduyin@engr.wisc.edu

* To whom correspondence should be addressed.
Quality of life of the elderly in Singapore's multi‐racial society
Authors: Wong Grace K.M.
Published: February 2003

With Singapore having the fifth fastest aging population in the world, the implications associated with such as a phenomenon have finally placed the elderly on the Singapore Government's national agenda in 1999. As the elderly constitute an increasing proportion of Singapore's population, it is pertinent to address their needs and concerns, which have direct impacts on their well‐being and quality of life. Also studies the context of a multi‐racial society. Evaluates the quality of life of the elderly in Singapore in terms of their overall life satisfaction as well as their perception of the importance and satisfaction towards the 17 domains of life identified. Using a five‐point Likert scale, reveals that the elderly in Singapore are generally satisfied with their quality of life, which is significantly influenced by three demographic variables. While the elderly perceive personal health condition, family ties and public safety to be more important, they tend to be more satisfied with family ties, public safety and public transportation, and are less satisfied with arts and culture as well as leisure and recreation facilities that are available in Singapore. Therefore suggests that the quality of life of the elderly in Singapore is more likely to be determined by its socio‐cultural context rather than along racial lines.
Performance, risk and strategy in privatised, regulated industries
Authors: Parker David
Published: February 2003

Internationally public utilities, sometimes referred to as network industries, are being privatised and dedicated regulatory structures to protect the public interest are being introduced. This study looks at the related issues of post‐privatisation performance, regulatory risk and management strategies in privatised public utilities, drawing on evidence from the UK. The main findings are, first, that in assessing the impact of privatisation on economic performance it is difficult to separate out the effects of ownership, competition, regulation and technological change. Second, that in terms of the distribution of the efficiency gains, initially investors were the main beneficiaries in the UK, but consumers gained as competition developed and regulation tightened. Third, regulated enterprises are subject to regulatory risk as well as commercial risk with implications for types of management strategies adopted. Following privatisation the dynamics of regulation involve both the regulator and management learning about regulation and the optimal strategies to adopt. The UK's experiences are educational for those countries now contemplating or in the process of introducing privatisation programmes.
Benchmarking supply chain management practice in New Zealand
Authors: Basnet Chuda , Corner Jim , Wisner Joel , Tan Keah‐Choon
Published: February 2003

This paper reports on a benchmarking study carried out on supply chain management (SCM) activities of manufacturing organisations in New Zealand. The purpose of the paper is to report the current state of the play in this area. A postal survey was carried out to ascertain the status of SCM adoption in New Zealand, and identify the issues in SCM that are significant for New Zealand manufacturers. The findings suggest that although there is awareness of the SCM concept in New Zealand, the adoption of the newer concepts of SCM is not very far advanced.
An Umbraviral Protein, Involved in Long-Distance RNA Movement, Binds Viral RNA and Forms Unique, Protective Ribonucleoprotein Complexes
Authors: Taliansky Michael , Roberts Ian M. , Kalinina Natalia , Ryabov Eugene V. , Raj Shri Krishna , Robinson David J. , Oparka Karl J.
Published: February 2003

Umbraviruses are different from most other viruses in that they do not encode a conventional capsid protein (CP); therefore, no recognizable virus particles are formed in infected plants. Their lack of a CP is compensated for by the ORF3 protein, which fulfils functions that are provided by the CPs of other viruses, such as protection and long-distance movement of viral RNA. When the
Groundnut rosette virus
(GRV) ORF3 protein was expressed from
Tobacco mosaic virus
(TMV) in place of the TMV CP [ΤMV(ORF3)], in infected cells it interacted with the TMV RNA to form filamentous ribonucleoprotein (RNP) particles that had elements of helical structure but were not as uniform as classical virions. These RNP particles were observed in amorphous inclusions in the cytoplasm, where they were embedded within an electron-dense matrix material. The inclusions were detected in all types of cells and were abundant in phloem-associated cells, in particular companion cells and immature sieve elements. RNP-containing complexes similar in appearance to the inclusions were isolated from plants infected with ΤMV(ORF3) or with GRV itself. In vitro, the ORF3 protein formed oligomers and bound RNA in a manner consistent with its role in the formation of RNP complexes. It is suggested that the cytoplasmic RNP complexes formed by the ORF3 protein serve to protect viral RNA and may be the form in which it moves through the phloem. Thus, the RNP particles detected here represent a novel structure which may be used by umbraviruses as an alternative to classical virions.
Role of Quail in the Interspecies Transmission of H9 Influenza A Viruses: Molecular Changes on HA That Correspond to Adaptation from Ducks to Chickens
Authors: Perez Daniel R. , Lim Wilina , Seiler Jon P. , Yi Guan , Peiris Malik , Shortridge Kennedy F. , Webster Robert G.
Published: February 2003

H9 influenza viruses have become endemic in land-based domestic poultry in Asia and have sporadically crossed to pigs and humans. To understand the molecular determinants of their adaptation to land-based birds, we tested the replication and transmission of several 1970s duck H9 viruses in chickens and quail. Quail were more susceptible than chickens to these viruses, and generation of recombinant H9 viruses by reverse genetics showed that changes in the HA gene are sufficient to initiate efficient replication and transmission in quail. Seven amino acid positions on the HA molecule corresponded to adaptation to land-based birds. In quail H9 viruses, the pattern of amino acids at these seven positions is intermediate between those of duck and chicken viruses; this fact may explain the susceptibility of quail to duck H9 viruses. Our findings suggest that quail provide an environment in which the adaptation of influenza viruses from ducks generates novel variants that can cross the species barrier.
Beating Atrial Septal Defect Closure Monitored by Epicardial Real-Time Three-Dimensional Echocardiography Without Cardiopulmonary Bypass
Authors: Suematsu Yoshihiro , Takamoto Shinichi , Kaneko Yukihiro , Ohtsuka Toshiya , Takayama Hiroo , Kotsuka Yutaka , Murakami Arata
Published: February 2003

Background—

We assessed the feasibility of beating atrial septal defect (ASD) closure monitored by real-time 3D echocardiography (RT3DE).

Methods and Results—

RT3DE was developed with prototype ultrasound equipment consisting of a high-speed 3D rendering unit with a frame rate of 5 to 10 frames/s. We also developed a prototype semiautomatic suture device and suture cutting system. In the experiment, 12 mongrel dogs were anesthetized, and after median sternotomy, the echo probe was applied directly to the surface of the right atrium. Three surgical maneuvers (balloon atrial septectomy, enlargement of the ASD, and ASD closure) were performed through the atrial port inserted into the right atrial appendage. The heart was then excised, and the area of the ASD measured by RT3DE was compared with its area measured directly. The ASD was successfully closed in all experimental animals except the first 2. Examination of the excised heart showed that none of the sutures were loose. The mean area of the ASD was 82.5±38.6 mm
2
when measured by RT3DE and 81.6±38.2 mm
2
when measured directly, and there was a significant correlation between the areas measured by RT3DE and those measured directly (echo measurements=1.007×direct measurements+0.337;
P
<0.0001). A Bland-Altman analysis revealed close agreement between the results obtained by the 2 methods (7.807 mm
2
upper and −6.024 mm
2
lower limit of agreement).

Conclusions—

Introduction of RT3DE, a semiautomatic suture device, and a suture cutting system made beating ASD closure without cardiopulmonary bypass possible.
Association Between Plasma Levels of Monocyte Chemoattractant Protein-1 and Long-Term Clinical Outcomes in Patients With Acute Coronary Syndromes
Authors: de Lemos James A. , Morrow David A. , Sabatine Marc S. , Murphy Sabina A. , Gibson C. Michael , Antman Elliott M. , McCabe Carolyn H. , Cannon Christopher P. , Braunwald Eugene
Published: February 2003

Background—

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine responsible for the recruitment of monocytes to sites of inflammation. MCP-1 appears to play a critical role at multiple stages in atherosclerosis, including the initiation of the fatty streak, promotion of plaque instability, and remodeling after myocardial infarction.

Methods and Results—

MCP-1 was measured from frozen plasma specimens in 279 healthy volunteers and 2270 patients with acute coronary syndromes enrolled in the Oral Glycoprotein IIb/IIIa Inhibition with Orbofiban in Patients with Unstable Coronary Syndromes (OPUS-TIMI) 16 trial. Median [25th, 75th percentiles] MCP-1 levels were 157 [124, 196] pg/mL in healthy volunteers and 178 [128, 238] pg/mL in the OPUS-TIMI 16 population (
P
<0.001). In OPUS-TIMI 16, baseline MCP-1 levels were associated with older age, female sex, hypertension, diabetes, prior coronary disease, and renal insufficiency (
P
<0.01 for each) but not with smoking status, body mass index, ejection fraction, troponin I or C-reactive protein. After adjustment for differences in baseline characteristics, ECG changes, troponin I, and C-reactive protein, an MCP-1 level >75th percentile (corresponding to the 90th percentile in the healthy volunteers) was associated with an increased risk of death or myocardial infarction through 10 months of follow-up (adjusted hazard ratio, 1.53; 95% CI, 1.09 to 2.14;
P
=0.01).

Conclusions—

In a large cohort of patients with acute coronary syndromes, an elevated baseline level of MCP-1 was associated both with traditional risk factors for atherosclerosis as well as an increased risk for death or myocardial infarction, independent of baseline variables. Because it appears to play a crucial role at multiple stages of atherosclerosis, MCP-1 is attractive as a surrogate biomarker and merits further study as a potential therapeutic target.
Angiostatin selectively inhibits signaling by hepatocyte growth factor in endothelial and smooth muscle cells
Authors: Wajih Nadeem , Sane David C.
Published: February 2003

Angiostatin, an inhibitor of angiogenesis, contains 3 to 4 kringle domains that are derived from proteolytic cleavage of plasminogen. The antiangiogenic effects of angiostatin occur, in part, from its inhibition of endothelial cell surface adenosine triphosphate synthase, integrin functions, and pericellular proteolysis. Angiostatin has structural similarities to hepatocyte growth factor (HGF; “scatter factor”), a promoter of angiogenesis, that induces proliferation and migration of both endothelial and smooth muscle cells via its cell surface receptor, c-met. We hypothesized that angiostatin might block HGF-induced signaling in endothelial and smooth muscle cells. Angiostatin inhibited HGF-induced phosphorylation of c-met, Akt, and ERK1/2. Angiostatin also significantly inhibited proliferation of human umbilical vein endothelial cells (HUVECs) induced by HGF. In contrast, angiostatin did not inhibit vascular endothelial growth factor (VEGF)–or basic fibroblast growth factor (bFGF)–induced signaling events or HUVEC proliferation. Angiostatin bound to immobilized truncated c-met produced by A431 cells and could be immunoprecipitated as a complex with soluble c-met. HGF inhibited the binding of 125I-angiostatin to HUVECs. Soluble c-met, produced by several tumor cell lines, could inhibit the antiangiogenic effect of angiostatin. The disruption of HGF/c-met signaling is a novel mechanism for the antiangiogenic effect of angiostatin.
T-cell epitopes within the complementarity-determining and framework regions of the tumor-derived immunoglobulin heavy chain in multiple myeloma
Authors: Hansson Lotta , Rabbani Hodjattallah , Fagerberg Jan , Österborg Anders , Mellstedt Håkan
Published: February 2003

The idiotypic structure of the monoclonal immunoglobulin (Ig) in multiple myeloma (MM) might be regarded as a tumor-specific antigen. The present study was designed to identify T-cell epitopes of the variable region of the Ig heavy chain (VH) in MM (n = 5) using bioinformatics and analyze the presence of naturally occurring T cells against idiotype-derived peptides. A large number of human-leukocyte-antigen (HLA)–binding (class I and II) peptides were identified. The frequency of predicted epitopes depended on the database used: 245 in bioinformatics and molecular analysis section (BIMAS) and 601 in SYFPEITHI. Most of the peptides displayed a binding half-life or score in the low or intermediate affinity range. The majority of the predicted peptides were complementarity-determining region (CDR)–rather than framework region (FR)–derived (52%-60% vs 40%-48%, respectively). Most of the predicted peptides were confined to the CDR2-FR3-CDR3 “geographic” region of the Ig-VH region (70%), and significantly fewer peptides were found within the flanking (FR1-CDR1-FR2 and FR4) regions (P < .01). There were 8– to 10–amino acid (aa) long peptides corresponding to the CDRs and fitting to the actual HLA-A/B haplotypes that spontaneously recognized, albeit with a low magnitude, type I T cells (interferon γ), indicating an ongoing major histocompatibility complex (MHC) class I–restricted T-cell response. Most of those peptides had a low binding half-life (BIMAS) and a low/intermediate score (SYFPEITHI). Furthermore, 15- to 20-aa long CDR1-3–derived peptides also spontaneously recognized type I T cells, indicating the presence of MHC class II–restricted T cells as well. This study demonstrates that a large number of HLA-binding idiotypic peptides can be identified in patients with MM. Such peptides may spontaneously induce a type I MHC class I– as well as class II–restricted memory T-cell response.
HES-1 preserves purified hematopoietic stem cells ex vivo and accumulates side population cells in vivo
Authors: Kunisato Atsushi , Chiba Shigeru , Nakagami-Yamaguchi Etsuko , Kumano Keiki , Saito Toshiki , Masuda Shigeo , Yamaguchi Tomoyuki , Osawa Masatake , Kageyama Ryoichiro , Nakauchi Hiromitsu , Nishikawa Mitsuo , Hirai Hisamaru
Published: February 2003

Mouse long-term hematopoietic reconstituting cells exist in the c-Kit+Sca-1+Lin− (KSL) cell population; among them, CD34low/− cells represent the most highly purified population of hematopoietic stem cells in the adult bone marrow. Here, we demonstrate that retrovirus-mediated transduction of CD34low/−c-Kit+Sca-1+Lin−(34−KSL) cells with the HES-1 gene, which encodes a basic helix-loop-helix transcription factor functioning downstream of the Notch receptor, and is a key molecule for the growth phase of neural stem cells in the embryo, preserves the long-term reconstituting activity of these cells in vitro. We also show that cells derived from the HES-1–transduced 34−KSL population produce progenies characterized by negative Hoechst dye staining, which defines the side population, and by CD34low/− profile in the bone marrow KSL population in each recipient mouse at ratios 3.5- and 7.8-fold those produced by nontransduced 34−KSL-derived competitor cells. We conclude that HES-1 preserves the long-term reconstituting hematopoietic activity of 34−KSL stem cells ex vivo. Up-regulation of HES-1 protein in the 34−KSL population before unnecessary cell division, that is, without retrovirus transduction, may represent a potent approach to absolute expansion of hematopoietic stem cells.
High-dose immune suppression and autologous hematopoietic stem cell transplantation in refractory Crohn disease
Authors: Burt Richard K. , Traynor Ann , Oyama Yu , Craig Robert
Published: February 2003

Two patients with severe Crohn disease, defined by a Crohn Disease Activity Index (CDAI) higher than 250 despite anti–tumor necrosis factor α (TNF-α), were treated by intense immune suppression and autologous hematopoietic stem cell transplantation (HSCT). Stem cells were mobilized from the peripheral blood using cyclophosphamide (2.0 g/m2) and granulocyte colony-stimulating factor (G-CSF; 5 μg/kg/d), enriched ex vivo by CD34+ selection, and reinfused after immune conditioning with cyclophosphamide (200 mg/kg) and equine anti–thymocyte globulin (ATG; 90 mg/kg). Patients have remained in remission (CDAI < 100) for 1 year since HSCT. We conclude that further HSCT studies for severe Crohn disease appear warranted.
An intronic polymorphism in the PAR-1 gene is associated with platelet receptor density and the response to SFLLRN
Authors: Dupont Annabelle , Fontana Pierre , Bachelot-Loza Christilla , Reny Jean-Luc , Bièche Ivan , Desvard Florence , Aiach Martine , Gaussem Pascale
Published: February 2003

Protease-activated receptor 1 (PAR-1), the main thrombin receptor on vascular cells, plays a key role in platelet activation. We examined the range of PAR-1 expression on platelets, obtained twice, 1 week apart, from 100 healthy subjects and found a 2-fold interindividual variation in receptor numbers (95% CI = 858-1700). Because PAR-1 density was stable with time (r2 = 76%,P < .001), we sought a genetic explanation for the observed variability. To validate this approach, we also analyzed the α2β1 genotype according to receptor density and platelet mRNA expression data. We found that the number of PAR-1 receptors on the platelet surface is associated with the intervening sequence IVSn−14 A/T intronic variation. The number of receptors was also found to govern the platelet response to the SFLLRN agonist, in terms of aggregation and P-selectin expression. The T allele (allelic frequency, 0.14) can be considered as an allele with decreased expression, because it was associated with lower PAR-1 expression on the platelet surface and with a lower response to SFLLRN. The IVSn−14 A/T intronic variation may therefore be clinically relevant.
Local and systemic effects of an allogeneic tumor cell vaccine combining transgenic human lymphotactin with interleukin-2 in patients with advanced or refractory neuroblastoma
Authors: Rousseau Raphaël F. , Haight Ann E. , Hirschmann-Jax Charlotte , Yvon Eric S. , Rill Donna R. , Mei Zhuyong , Smith Susan C. , Inman Shannon , Cooper Kristine , Alcoser Pat , Grilley Bambi , Gee Adrian , Popek Edwina , Davidoff Andrew , Bowman Laura C. , Brenner Malcolm K. , Strother Douglas
Published: February 2003

In murine models, transgenic chemokine–cytokine tumor vaccines overcome many of the limitations of single-agent immunotherapy by producing the sequence of T-cell attraction followed by proliferation. The safety and immunologic effects of this approach in humans were tested in 21 patients with relapsed or refractory neuroblastoma. They received up to 8 subcutaneous injections of a vaccine combining lymphotactin (Lptn)– and interleukin-2 (IL-2)–secreting allogeneic neuroblastoma cells in a dose-escalating scheme. Severe adverse reactions were limited to reversible panniculitis in 5 patients and bone pain in 1 patient. Injection-site biopsies revealed increased cellularity caused by infiltration of CD4+ and CD8+ lymphocytes, eosinophils, and Langerhans cells. Systemically, the vaccine produced a 2-fold (P = .035) expansion of CD4+ T cells, a 3.5-fold (P = .039) expansion of natural killer (NK) cells, a 2.1-fold (P = .014) expansion of eosinophils, and a 1.6-fold (P = .049) increase in serum IL-5. When restimulated in vitro by the immunizing cell line, T cells collected after vaccination showed a 2.3-fold increase (P = .02) of T-helper (TH2)–type CD3+IL-4+cells. Supernatant collected from restimulated cells showed increased amounts of IL-4 (11.4-fold; P = .021) and IL-5 (8.7-fold;P = .002). Six patients had significant increases in NK cytolytic activity. Fifteen patients made immunoglobulin G (IgG) antibodies that bound to the immunizing cell line. Measurable tumor responses included complete remission in 2 patients and partial response in 1 patient. Hence, allogeneic tumor cell vaccines combining transgenic Lptn with IL-2 appear to have little toxicity in humans and can induce an antitumor immune response.