bluuebunny/crossref_metadata_2025 huggingface dataset:
HGV/GB virus C transmission by blood components in patients undergoing open‐heart surgery
Authors: Sentjens Roel , Basaras Miren , Simmonds Peter , Vrielink Hans , Reesink Henk
Published: October 2003

BACKGROUND:  To establish the rate of HGV/GB virus C (GBV‐C) transmission by blood components in open‐heart surgery patients.

STUDY DESIGN AND METHODS:  From 55 patients receiving blood components, sera were collected before and 2, 4, 6, 8, 10, 12, 16, 20, 26, and 32 weeks after heart surgery. Serum samples from patients and implicated blood donations were tested for HGV/GBV‐C RNA by PCR. Recipients of RNA‐positive blood components were also tested for the presence of E2 antibodies (E2Ab) by ELISA.

RESULTS:  Of 55 recipients, 18 received RNA‐positive blood components. Of 14 recipients of RNA‐positive blood components, who were negative for RNA or E2Ab before transfusion, 8 became RNA positive and one developed E2Ab after transfusion. Three recipients of RNA‐positive blood components had E2Ab before transfusion, and none of these became RNA positive after transfusion. One of 18 recipients was RNA positive before and after transfusion. Of 55 recipients, 37 received RNA‐negative blood components: 34 were RNA negative before and after transfusion. Of 37 recipients, 3 were RNA positive before and after transfusion.

CONCLUSION:  Of susceptible patients, 64 percent became infected with HGV/GVC‐C when transfused with RNA‐positive blood components. E2Ab‐positive patients were protected against HGV/GBV‐C infection.
Hemochromatosis subjects as allogeneic blood donors: a prospective study
Authors: Leitman Susan F. , Browning Janet N. , Yau Yu Ying , Mason Glorice , Klein Harvey G. , Conry‐Cantilena Cathy , Bolan Charles D.
Published: October 2003

BACKGROUND:  Persons with hemochromatosis constitute a plentiful and willing source of blood for transfusion. A program was established and evaluated for treating persons with hemochromatosis in a donor center and making their blood available for transfusion.

STUDY DESIGN AND METHODS:  Phlebotomy therapy was performed free of charge regardless of whether subjects met criteria for allogeneic donation. A Hb level of 12.5 g per dL was used as the threshold for performing phlebotomy, and decreases in the MCV were used to guide the endpoints of therapy.

RESULTS:  A total of 130 subjects were consecutively enrolled: 74 percent were homozygous for the C282Y mutation in the HFE gene, 76 percent met eligibility criteria for allogeneic donation, and 55 percent were previous blood donors. A median of 20 weekly or biweekly phlebotomies (range, 7‐99) were performed before the MCV reached the targeted endpoint of 3 percent below baseline, at which time the ferritin level was less than 30 µg per L and the transferrin saturation was less than 30 percent. The median phlebotomy interval necessary to keep the MCV at this level during maintenance therapy was 10 weeks. No incident seroconversions for agents of transfusion‐transmissible disease occurred during 1402 donations. All subjects testing positive for viral agents gave a prior history of deferrable risk. Twenty‐seven months after starting the program, hemochromatosis donors were contributing 14 percent of the RBC units collected for allogeneic use.

CONCLUSIONS:  Hemochromatosis subjects can safely and significantly augment the allogeneic blood supply. Provision of phlebotomy therapy unrestricted by considerations of cost or suitability for donation can improve access to care and remove incentives for incomplete risk disclosure.
Bacterial contamination of ex vivo processed PBPC products under clean room conditions
Authors: Ritter Markus , Schwedler Joachim , Beyer Jörg , Movassaghi Kamran , Mutters Reinier , Neubauer Andreas , Schwella Nimrod
Published: October 2003

BACKGROUND:  Patients undergoing high‐dose radio‐ and/or chemotherapy and autologous or allogeneic PBPC transplantation are at high risk for infections owing to profound immunosuppression. In this study, the rate of microbial contamination of ex vivo processed PBPC products was analyzed, comparing preparation under clean room conditions to standard laboratory conditions.

STUDY DESIGN AND METHODS:  After implementation of good manufacturing practice conditions in the two participating institutions, the microbial contamination rate of 366 PBPC harvests from 198 patients was determined under certified clean room conditions (Group A) from 2000 until 2002. To investigate influence of improved environmental conditions along with other parameters, this set of samples was compared with a historical control set of 1413 PBPC products, which have been processed ex vivo under a clean bench in a regular laboratory room and were harvested from 626 patients (Group B) from 1989 until 2000.

RESULTS:  In Group B microbial contamination was found in 74 PBPC products (5.2%) from 57 patients. In Group A microbial growth was detected in 3 leukapheresis products (0.8%) from 3 patients. After exclusion of PBPC products, which were probably contaminated before manipulation, statistical analysis showed a significant difference (χ2= 10.339; p < 0.001).

CONCLUSION:  These data suggest an impact of clean room conditions on the bacterial contamination rate of PBPC products. To identify confounding variables, variables like technique of leukapheresis, culture methodology, and microbial colonization of central venous catheters were taken into account. Further variables might be identified in following studies.
Mathematical structure of the temporal gauge in quantum electrodynamics
Authors: Löffelholz J. , Morchio G. , Strocchi F.
Published: October 2003

The conflict between Gauss’ law constraint and the existence of the propagator of the gauge fields, at the basis of contradictory proposals in the literature, is shown to lead to only two alternatives, both with peculiar features with respect to standard quantum field theory. In the positive (interacting) case, the Gauss’ law holds in operator form, but only the correlations of exponentials of gauge fields exist (nonregularity) and the space translations are not strongly continuous, so that their generators do not exist. Alternatively, a Källen–Lehmann representation of the two point function of Ai satisfying locality and invariance under space–time translations, rotations and parity is derived in terms of the two point function of Fμν; positivity is violated, the Gauss’ law does not hold, the energy spectrum is positive, but the relativistic spectral condition does not hold. In the free case, θ-vacua exist on the observable fields, but they do not have time translationally invariant extensions to the gauge fields; the vacuum is faithful on the longitudinal field algebra and defines a modular structure (even if the energy is positive). Functional integral representations are derived in both cases, with the alternative between ergodic measures on real random fields or complex Gaussian random fields.
Gauge principle revisited: Towards a unification of space–time and internal gauge interactions
Authors: Aldaya V. , Jaramillo J. L. , Guerrero J.
Published: October 2003

The minimal coupling principle is revisited under the quantum perspectives of the space–time symmetry. This revision is better realized on a group approach to quantization (GAQ) where group cohomology and extensions of groups play a preponderant role. We first consider the case of the electromagnetic potential; the Galilei and/or Poincaré group is (noncentrally) extended by the “local” U(1) group. The resulting group can also be seen as a central extension, parametrized by both the mass and the electric charge, of an infinite-dimensional group, on which GAQ leads to the dynamics of a particle moving in the presence of an electromagnetic field. Then we try the gravitational interaction of a particle by making the space–time translations “local.” However, promoting to “local” the space–time subgroup of the true symmetry of the quantum free relativistic particle, i.e., the centrally extended by U(1) Poincaré group, results in a new electromagneticlike force of pure gravitational origin. This is a consequence of the space–time translations not being an invariant subgroup of the extended Poincaré group and constitutes a preliminary attempt to a nontrivial mixing of space–time and internal gauge interactions.
Embeddings in space–times sourced by scalar fields
Authors: Anderson E. , Dahia F. , Lidsey J. E. , Romero C.
Published: October 2003

The extension of the Campbell–Magaard embedding theorem to general relativity with minimally coupled scalar fields is formulated and proven. The result is applied to the case of a self-interacting scalar field for which new embeddings are found, and to Brans–Dicke theory. The relationship between the Campbell–Magaard theorem and the General Relativity Cauchy and initial value problems is outlined.
A further solvable three-body problem in the plane
Authors: Calogero F. , Françoise J.-P. , Guillot A.
Published: October 2003

The solution is provided of a three-body problem in the plane, which is the third of a trio recently identified as likely to display a particularly simple time-evolution hence to be amenable to exact treatment. This conjecture, already validated by providing the solution of the first two of these three models, is now completely proven by exhibiting the solution of the third. This finding also demonstrates the conjectured super-Painlevé character of certain nonlinear ordinary differential equations, namely, the fact that their general solution is an entire function of the independent variable.
Stochastic dynamics of the scattering amplitude generating K-distributed noise
Authors: Field Timothy R. , Tough Robert J. A.
Published: October 2003

We derive the stochastic dynamics of the complex valued amplitude resulting from coherent scattering from a random population of scatterers when this becomes asymptotically large. Considerations of a random walk model, introduced by Jakeman, are used to derive stochastic differential equations for the amplitude and corresponding intensity and phase stochastic processes. An analysis of the correlation structure in the fluctuations is provided and interpreted geometrically in terms of the gauge invariant properties of the field and the Markov property. A Fokker–Planck description for the evolution of the probability density is given and the equilibrium and detailed balance conditions shown to hold. Expressions for the intensity autocorrelation function and power spectral density are provided in closed form. The practical implications of the stochastic theory are discussed.
The Hopf algebra of identical, fermionic particle systems—Fundamental concepts and properties
Authors: Cassam-Chenaı̈ Patrick , Patras Frédéric
Published: October 2003

The Hopf algebra structure of the fermionic Fock space is unravelled. The tools provided by the Hopf algebra formalism are used to rederive in a more straightforward fashion some known theorems and to open the way to natural generalizations of these results. The algebraic concepts of rank, depth and length of a wave function are given. They allow one to cast a wave function into a canonical form that is simpler and more appropriate to a physical interpretation or a numerical treatment. An original algorithm to re-expand a wave function with the least possible number of spin orbitals is described.
Net accelerations of charged particles by a generalized electromagnetic wave
Authors: Akimoto K.
Published: October 2003

Several mechanisms for a general electromagnetic (EM) wave to provide net energy as well as net longitudinal velocity shifts to particles that are initially propagating parallel to the wave with various velocities are systematically investigated. Three pairs of acceleration mechanisms, each of which is comprised of a transit-type and a reflection-type mechanism, are identified. Each pair is produced by gradually breaking the symmetry of a plane EM wave. The specific means adopted to break the symmetry of a plane EM wave are: (1) spatial localization (pulse formation); (2) introduction of wave dispersion; and/or (3) application of an external magnetic field. The spatial localization yields well-known but generalized transit-time accelerations as well as reflections. The former is particularly effective if the pulse is sufficiently short compared with its wavelength, e.g., mono- or sub-cycle pulse, etc. However, its effective velocity ranges are rapidly reduced for longer wavepackets. Separation of the phase velocity and the group velocity due to the introduction of dispersion leads to quasi-trapping of nearly resonant particles and reflections due to ponderomotive force. And finally, the application of an external magnetic field yields cyclotron resonance accelerations and reflections due to them, both of which are extremely efficient. The effects of wave dispersion are particularly emphasized. Each mechanism may be well described analytically, and play a significant role under proper conditions. The results may be utilized among others for the analyses of various plasma wave turbulence as well as of particle accelerators.
Exponential variational expansion in relative coordinates for highly accurate bound state calculations in four-body systems
Authors: Harris Frank E. , Frolov Alexei M. , Smith Vedene H.
Published: October 2003

Exponential variational expansions in relative coordinates are considered for four-body systems. All matrix elements needed for bound-state calculations are expressed as linear combinations of fifth- and sixth-order derivatives of a basic four-body integral. Computation of the basic four-body integral and its derivatives is performed directly, i.e., without any use of the branch tracking in the complex plane that is required in the Fromm/Hill approach, and by methods that take into account the termwise singularities of the formulas. The final computational procedure is relatively simple, physically transparent, and numerically stable. The methods are illustrated with sample data that show the importance of a singularity-canceling approach and that the increased precision thereby made possible permits more accurate wave function optimization than heretofore.
Observation of crystallization of amorphous solid water under the conditions of secondary emission mass spectrometric experiments
Authors: Kosevich M. V. , Boryak O. A. , Shelkovsky V. S. , Orlov V. V.
Published: October 2003

A phenomenon of termination of sputtering of protonated water clusters (H2O)nH+ in low-temperature secondary emission mass spectrometric studies of solid water is observed in the temperature range of crystallization of amorphous solid water (ASW). In this range the mass spectra contained only H3O+, H2O+•, and OH+ ions. The following explanation of the phenomenon revealed is suggested: the heat supplied to the ASW sample by the bombarding particles is spent on initiation of an amorphous–crystalline transition within the condensed sample but not for the transfer of the sample matter to the gas phase. At the same time heat released on crystallization causes a local rise in temperature of the crystallizing sample surface, which enhances the rate of sublimation of ice. The resulting increased concentration of subliming water molecules over the sample surface is reflected in a growth of the abundance of H2O+• molecular-ion radical, produced by gas-phase ionization mechanism. The appearance of a set of low-mass peaks in the course of crystallization observed for some types of ASW samples is explained by the release of gases trapped in the ASW film during its growth.
Confinement and compression of magnetic flux by plasma shells
Authors: Rudakov L. I. , Chuvatin A. , Velikovich A. L. , Davis J.
Published: October 2003

Confinement and compression of magnetic flux by plasma shells is of interest for a variety of applications associated with keV x-ray production in pulsed-power driven Z-pinch plasma radiation sources (PRS). Confinement of a Bz field with a Bθ field of the pinch current can help stabilize the implosion of a shell from a large initial radius. Compression of the azimuthal magnetic flux in the PRS (secondary) circuit with a plasma shell driven by Bθ field of the primary circuit may represent a new opportunity for using a low-cost, relatively slow pulsed power to generate large amounts of keV x rays. The magnetic field has to be compressed and/or confined by low-mass plasma shells emitting soft x-ray radiation that limits the temperature and conductivity of the shell plasma. The thickness of a plasma shell is established self-consistently during the implosion, and it is not obvious whether or not the shell becomes thick enough to confine or compress the magnetic flux. The results of analytical theory and numerical simulations demonstrate that the flux-compressing capability of a low-beta plasma shell is surprisingly good because the shell is shown to dynamically adjust its thickness so that it always remains of the order of its skin depth. The self-similar profiles of confined magnetic field predicted by the theory are consistently reproduced in the simulations.
Influence of ion bombardment on transport properties and exchange bias in magnetic tunnel junctions
Authors: Schmalhorst J. , Höink V. , Reiss G. , Engel D. , Junk D. , Schindler A. , Ehresmann A. , Schmoranzer H.
Published: October 2003

Magnetic tunnel junctions (Mn83Ir17/Co70Fe30/AlOx/Ni80Fe20) were bombarded by 10–20 keV He+ ions in an applied magnetic field to manipulate the exchange bias of the magnetically hard electrode. The tunneling magnetoresistance of the bombarded junctions is up to 37.8% for ion doses high enough to ensure a well defined exchange bias. This should allow the preparation of high quality tunnel junctions with magnetic micropatterned hard electrodes. For very high ion doses the tunneling magnetoresistance starts to decrease, whereas the area resistance product increases. Possible explanations based on structural alterations of the tunneling barrier are discussed.
Recovery of a potential from the ratio of reflection and transmission coefficients
Authors: Aktosun Tuncay , Papanicolaou Vassilis G.
Published: October 2003

For the one-dimensional Schrödinger equation, the analysis is provided to recover the potential from the data consisting of the ratio of a reflection coefficient to the transmission coefficient. It is investigated whether such data uniquely constructs a reflection coefficient, the number of bound states, bound-state energies, bound-state norming constants, and a corresponding potential. In all three cases when there is no knowledge of the support of the potential, the support of the potential is confined to a half-line, and the support is confined to a finite interval, various uniqueness and nonuniqueness results are established, the precise criteria are provided for the uniqueness and the nonuniqueness and the degree of nonuniqueness, and the recovery is illustrated with some explicit examples.
Electron-inertia effects on driven magnetic field reconnection
Authors: Al-Salti N. , Shivamoggi B. K.
Published: October 2003

Electron-inertia effects on the magnetic field reconnection induced by perturbing the boundaries of a slab of plasma with a magnetic neutral surface inside are considered. Energetics of the tearing mode dynamics with electron inertia which controls the linearized collisionless magnetohydrodynamics (MHD) are considered with a view to clarify the role of the plasma pressure in this process. Cases with the boundaries perturbed at rates slow or fast compared with the hydromagnetic evolution rate are considered separately. When the boundaries are perturbed at a rate slow compared with the hydromagnetic evolution rate and fast compared with the resistive diffusion rate, the plasma response for early times is according to ideal MHD. A current sheet formation takes place at the magnetic neutral surface for large times in the ideal MHD stage and plasma becomes motionless. The subsequent evolution of the current sheet is found to be divided into two distinct stages: (i) the electron-inertia stage for small times (when the current sheet is very narrow); (ii) the resistive-diffusion stage for large times. The current sheet mainly undergoes exponential damping in the electron-inertia regime while the bulk of the diffusion happens in the resistivity regime. For large times of the resistive-diffusion stage when plasma flow is present, the current sheet completely disappears and the magnetic field reconnection takes place. When the boundaries are perturbed at a rate fast compared even with the hydromagnetic evolution rate, there is no time for the development of a current sheet and the magnetic field reconnection has been found not to take place.
Givental formula in terms of Virasoro operators
Authors: Alexandrov A.
Published: October 2003

We present a conjecture that the universal enveloping algebra of differential operators ∂/∂tk over ℂ coincides in the origin with the universal enveloping algebra of the (Borel subalgebra of) Virasoro generators from the Kontsevich model. Thus, we can decompose any (pseudo)differential operator to a combination of the Virasoro operators. Using this decomposition we present the right-hand side of the Givental formula [math.AG/0008067] as a constant part of the differential operator we introduce. In the case of CP1 studied in the paper by Song and Song [hep-th/0103254], the left-hand side of the Givental formula is a unit, which imposes certain constraints on this differential operator. We explicitly check that these constraints are correct up to O(q4). We also propose a conjecture of factorization modulo Hirota equation of the differential operator introduced and check this conjecture with the same accuracy.
Optical and electrical properties of homoepitaxially grown multiquantum well InGaN/GaN light-emitting diodes
Authors: Franssen G. , Litwin-Staszewska E. , Piotrzkowski R. , Suski T. , Perlin P.
Published: October 2003

We have studied the electrical and optical properties of homoepitaxially grown InGaN/GaN multiquantum-well light-emitting diodes over a wide range of temperatures and currents. We found thermionic emission rather than tunneling transport to be the most probable mechanism responsible for radiative recombination processes. As we point out, the thermal activation energies of Si donors in the n-type GaN and Mg acceptors in the p-type GaN can explain the temperature dependence of the device series resistance. Furthermore, the presence of strong localization effects in the active InGaN layers can be deduced from the observed considerable blueshifts of the electroluminescence emission peak with increasing temperature and current. We found the values of the internal and external quantum efficiencies of homoepitaxially grown light emitting diodes to be 38% and 1.9%, respectively.
Perturbation expansions for a class of singular potentials
Authors: Saad Nasser , Hall Richard L. , von Keviczky Attila B.
Published: October 2003

Harrell’s modified perturbation theory [Ann. Phys. (N.Y.) 105, 379 (1977)] is applied and extended to obtain nonpower perturbation expansions for a class of singular Hamiltonians H=−(d2/dx2)+x2+(A/x2)+(λ/xα) (A⩾0,α>2), known as generalized spiked harmonic oscillators. The perturbation expansions developed here are valid for small values of the coupling λ>0, and they extend the results which Harrell obtained for the spiked harmonic oscillator A=0. Formulas for the excited states are also developed.
Streamerless guided electric discharges triggered by femtosecond laser filaments
Authors: Gordon D. F. , Ting A. , Hubbard R. F. , Briscoe E. , Manka C. , Slinker S. P. , Baronavski A. P. , Ladouceur H. D. , Grounds P. W. , Girardi P. G.
Published: October 2003

The time evolution of electrical discharges induced and guided between the cathode of a Van de Graf generator and a ground sphere was studied using a 100 fs Ti:Sapphire laser. Nonlinear focusing and ionization effects produce optical and plasma filaments in the discharge region. Streak camera images often exhibit streamers that propagate towards the cathode, but sudden discharge triggering is frequently observed with no streamer precursors. The typical discharge triggering delay time was measured to be 150 ns. Similar time delays were obtained from an air chemistry code used to model the long time behavior of the plasma induced by the short laser pulse. The model shows that ohmic heating of the filament plasma persists over long time scales and inhibits the decay of electron density due to recombination and attachment processes. Eventually the rise in electron temperature causes the avalanche rate to increase to the point where breakdown occurs. The hydrodynamic density reduction process reported by Tzortzakis et al. [Phys. Rev. E 64, 057401 (2001)] is also taken into consideration. Its main effect is found to be a hastening of the breakdown process.
Effects of magnetized ions on the lower-hybrid-drift instability
Authors: Yoon Peter H. , Lui Anthony T. Y.
Published: October 2003

The present paper investigates the effects of magnetized ions on the lower-hybrid-drift instability (LHDI). Since LHDI is operative over a wide frequency range covering multiple harmonics of ion-cyclotron frequency, it is expected that the instability must essentially correspond to a multiple-harmonic drift-ion-cyclotron instability if the assumption of ion demagnetization is not imposed, and that LHDI is only an approximation which results when the individual harmonic structure is smoothed over. However, such a speculation has not been explored in detail to this date. The present paper addresses just such a problem. It is shown that indeed, LHDI is a result of the coupling of the drift mode and multiple-harmonic ion-cyclotron modes. It is found, however, that the unstable mode forms a smooth unbroken curve in frequency-wave-number dispersion space, intersected at regular frequency intervals by each ion-cyclotron harmonic. Thus, it is concluded that treating the ions as “unmagnetized” at the outset is largely justifiable. However, it is also found that the unmagnetized treatment leads to lower growth rate for LHDI.
SnGe superstructure materials for Si-based infrared optoelectronics
Authors: Bauer M. R. , Cook C. S. , Aella P. , Tolle J. , Kouvetakis J. , Crozier P. A. , Chizmeshya A. V. G. , Smith David J. , Zollner S.
Published: October 2003

We report growth of device-quality, single-crystal SnxGe1−x alloys (with x=0.02–0.2) directly on Si via chemical vapor deposition with deuterium-stabilized Sn hydrides. The high Sn-content materials are stabilized with ordered superstructures that gives rise to a layered structure adjacent to the Si substrate. Density functional theory simulations were used to elucidate the structural and bonding behavior of this material. Optical determinations show a Ge-like band structure that is substantially redshifted compared to that of elemental Ge. Thus, these systems are excellent candidates for a new generation of infrared devices, with the critical advantage that they can be grown directly on Si.
Characteristics of LaAlO3 gate dielectrics on Si grown by metalorganic chemical vapor deposition
Authors: Li Ai-Dong , Shao Qi-Yue , Ling Hui-Qin , Cheng Jin-Bo , Wu Di , Liu Zhi-Guo , Ming Nai-Ben , Wang Cathy , Zhou Hong-Wei , Nguyen Bich-Yen
Published: October 2003

Amorphous LaAlO3 (LAO) gate dielectric thin films have been deposited on Si substrates using La(dpm)3 and Al(acac)3 sources by low-pressure metalorganic chemical vapor deposition. The growth mechanism, interfacial structure, and electrical properties have been investigated by various techniques. The ultrathin films show smaller roughness of ∼0.3 nm, larger band gap of 6.47 eV, and good thermal stability. The growth follows a chemical dynamic control mechanism. High-resolution transmission electron microscopy confirms there exists no interfacial layer, or only thinner ones, between LAO and Si. X-ray photoelectron spectroscopy analyses reveal that the thinner interfacial layer is compositionally graded La–Al–Si–O silicate and Al element is deficient in the interfacial layer. The reliable value of equivalent oxide thickness around 1.2 nm of LAO/Si has been achieved.
On the nitrogen vacancy in GaN
Authors: Look D. C. , Farlow G. C. , Drevinsky P. J. , Bliss D. F. , Sizelove J. R.
Published: October 2003

The dominant electrically active defect produced by 0.42 MeV electron irradiation in GaN is a 70 meV donor. Since only N-sublattice displacements can be produced at this energy, and since theory predicts that the N interstitial is a deep acceptor in n-type GaN, we argue that the 70 meV donor is most likely the isolated N vacancy. The background shallow donors, in the 24–26 meV range, actually decrease in concentration, probably due to interactions with mobile N interstitials that are produced by the irradiation. Thus, the recent assignment of a photoluminescence (PL) line as an exciton bound to a 25 meV N-vacancy donor is incompatible with our results. Moreover, we do not observe that PL line in our sample.
AlGaN multiple-quantum-well-based, deep ultraviolet light-emitting diodes with significantly reduced long-wave emission
Authors: Zhang JianPing , Wu Shuai , Rai Shiva , Mandavilli Vasavi , Adivarahan Vinod , Chitnis Ashay , Shatalov Maxim , Khan Muhammad Asif
Published: October 2003

We report on a deep UV light-emitting diode over sapphire substrate with AlGaN multiple-quantum-well active region. Pulsed atomic-layer epitaxy deposited low-defect AlN/AlGaN buffers and an optimized active layer design yielded a sharp quantum-well emission peak at 287 nm and very little long-wave secondary emission. For a 100 μm×100 μm unpackaged device, a power of 27 μW at 20 mA dc and a peak external quantum efficiency of 0.1% at 100 mA pulse pumping were measured. Flip-chip packaging should increase these numbers nearly by a factor of 3.
Exploration of customer horizons to measure understanding of netchains
Authors: Storer Christine E. , Holmen Elsebeth , Pedersen Ann‐Charlott
Published: October 2003

The importance of a market orientation as the basis for meeting customer expectations is well known in marketing. In applying this concept to networks or netchains, the concept “customer horizon” is proposed to measure the ability to name or identify downstream customers and their requirements. A case study of five organizations in a netchain is examined to determine each company's customer horizon in terms of “breadth” and “length”. Based on the findings, it is suggested that companies can choose between alternative configurations of customer horizons. It is argued that it may be important to watch out for narrow and short customer horizons – especially when customer satisfaction is low, end consumer requirements are changing and/or these changes are not being communicated upstream to suppliers.
The Political Manipulation of Group Composition: Engineering the Decision Context
Authors: Hoyt Paul D.
Published: October 2003

Group decisions are not made solely by evaluating the merits of the contending positions. Instead, actors may engage in manipulation to increase the fortunes of their policy preference. Actors may manipulate information, group procedures, or group composition. Using a model of group socialization, this paper argues that a manipulator may seek to alter the group composition as to access and/or status. In doing so, the manipulator seeks to create a more favorable decision environment. This political perspective maintains that the dynamic nature of group composition provides an opportunity for a manipulator to engineer the decision context, potentially affecting the group's decisional output. Strategies and tactics of composition manipulation are presented and then utilized to analyze the American decision process during the Iranian revolution.
Sustainable Pressure for “Women‐Friendliness” in Sweden
Authors: Gustafsson Gunnel
Published: October 2003

This paper describes how Swedish women argue and act in order to improve their quality of life. It is based on a citizen survey and on interviews with leaders of a broadly defined women's movement. The thesis is that women are in the process of developing their own democratic practice. They thereby challenge the assumption that general suffrage and numerical equality of representation are sufficient conditions for transforming the contemporary gender power order into one characterized by equality of power between women and men. The empirical data show that there is a great deal of variation in perceptions of problems and ways of accomplishing change. The existence of somewhat different priorities and plural feminist strategies for change—state feminist, interest group–based, civil, and segregated—are interpreted as speaking in favor of the sustainability of such pressure for “women‐friendliness” in Sweden.
Feminists, Islamists, and Political Change in Turkey
Authors: Arat Yesim
Published: October 2003

This paper examines how some feminist and Islamist women in Turkey helped bring about change in political values during the past decade. The traditional political culture upheld statist, corporatist (as opposed to liberal, individualist) norms. The state controlled religion in the name of secularism and limited democracy within the confines of formal equality. Both feminists and Islamists contested traditional political values by insisting on their own definition of their interests, as opposed to those that were state‐enforced. The feminists questioned the justice of formal equality as they sought substantive equality; Islamist women challenged the secular concept of equality as they insisted on the justice of male‐female complementarity. Both groups engaged in active politics and expanded the parameters of democratic participation as they sought substantive equality beyond formal equality. Yet the patriarchal heritage of Islam defined the limits of Islamist women's search for liberation within the confines of religion.
The Bioethical Structure of a Human Being
Authors: Copland Paul , Gillett Grant
Published: October 2003

ABSTRACT Bioethical debates such as those surrounding the manipulation of human embryos are often based on metaphysical assumptions that lack a foundation in the natural sciences. In this paper we support a gradualist position whereby the embryo progressively takes on the form and associated ethical significance of a human being. We support this position by introducing a concept of biological structure or form to show how the gradualist position has its metaphysical foundations in modern biology. The conceptual basis for form and structure are outlined and their compatibility with and basis in current empirical biology is demonstrated by some recent advances in our understanding of the processes of development from single cell to organism. We then briefly explore the ethical significance of accepting a form or structure based conception of biology for the status of the early embryo.
The skiving stock problem as a counterpart of the cutting stock problem
Authors: Zak E. J.
Published: October 2003

The cutting stock problem (CSP) is a particular case of the set‐covering problem. Similarly we introduce another class of combinatorial optimization problems called the skiving stock problem (SSP) as a particular case of the set‐packing problem. The SSP shares many properties and solving techniques with the CSP. When these two problem spaces are contrasted they illuminate one another in that they form a ‘dual’ relationship where techniques once thought to be applicable in one domain can be applied in the other. Furthermore the SSP, like the CSP, may have numerous applications in business and industry.
The Market's Differential Reactions to Forward‐Looking and Backward‐Looking Dividend Changes
Authors: Lee Bong‐Soo , Yan Nairong Allen
Published: October 2003

Empirical evidence on the signaling hypothesis of dividends is weak and mixed. Recent studies find that dividend changes reflect mostly current and past earnings but not future earnings. We provide a model in which not all dividend changes contain new information about future earnings. Some dividend decisions are backward looking (noninformation or nonsignaling events). Other dividend decisions are forward looking (information or signaling events). The model helps identify the two types of dividend changes and predicts that the market will respond strongly only to forward‐looking dividend changes. We provide evidence consistent with the implications of the model.
Kin Discrimination and the Benefit of Helping in Cooperatively Breeding Vertebrates
Authors: Griffin Ashleigh S. , West Stuart A.
Published: October 2003

In many cooperatively breeding vertebrates, a dominant breeding pair is assisted in offspring care by nonbreeding helpers. A leading explanation for this altruistic behavior is Hamilton's idea that helpers gain indirect fitness benefits by rearing relatives (kin selection). Many studies have shown that helpers typically provide care for relatives, but relatively few have shown that helpers provide closer kin with preferential care (kin discrimination), fueling the suggestion that kin selection only poorly accounts for the evolution of cooperative breeding in vertebrates. We used meta-analysis to show that (i) individuals consistently discriminate between kin, and (ii) stronger discrimination occurs in species where the benefits of helping are greater. These results suggest a general role for kin selection and that the relative importance of kin selection varies across species, as predicted by Hamilton's rule.
Antiviral Activity of RhoA-Derived Peptides against Respiratory Syncytial Virus Is Dependent on Formation of Peptide Dimers
Authors: Budge Philip J. , Lebowitz Jacob , Graham Barney S.
Published: October 2003

A synthetic peptide containing amino acids 77 to 95 of the intracellular GTPase RhoA has previously been shown to inhibit replication of respiratory syncytial virus (RSV) in cultured cells. We show that residues 80 to 90 of RhoA are sufficient for this activity and that the cysteine residue at position 83 is critical. Further studies with an optimal peptide sequence containing amino acids 80 to 94 of RhoA revealed that the antiviral potency of the peptide is dependent on the oxidation of cysteine 83. Size-exclusion chromatography and sedimentation equilibrium studies of the peptide comprising residues 80 to 94 revealed that it is capable of forming aggregates in both reduced and oxidized states. A peptide (83A) in which the cysteine residue is replaced by an alanine does not form dimers or higher-order aggregates and did not inhibit RSV replication at any concentration tested. These data indicate that formation of peptide multimers is necessary for the antiviral activities of RhoA-derived peptides and suggest that the observed antiviral activities of these peptides may be unrelated to the biological functions of their parent molecule.
In Vitro Activities of Garenoxacin (BMS-284756) against
Haemophilus influenzae
Isolates with Different Fluoroquinolone Susceptibilities
Authors: Pérez-Vázquez María , Román Federico , Aracil Belen , Cantón Rafael , Campos José
Published: October 2003

The in vitro activity of garenoxacin (BMS-284756) against 62 clinical
Haemophilus influenzae
isolates with different fluoroquinolone susceptibilities was determined by the microdilution susceptibility testing method and compared with the activities of other oral quinolones and nonquinolone oral antimicrobial agents. Cefixime presented the highest intrinsic activity (MIC at which 50% of the isolates tested were inhibited [MIC
50
], 0.01 μg/ml), followed by garenoxacin, moxifloxacin, and ciprofloxacin (MIC
50
, 0.06 μg/ml), levofloxacin (MIC
50
, 0.12 μg/ml), cefuroxime (MIC
50
, 1.0 μg/ml), and amoxicillin-clavulanate (MIC
50
, 1.0/0.5 μg/ml), amoxicillin (MIC
50
, 2 μg/ml), azithromycin (MIC
50
, 4 μg/ml), and erythromycin (MIC
50
, 8 μg/ml). In strains with ciprofloxacin MICs of ≤0.06 μg/ml, ciprofloxacin and garenoxacin displayed similar MIC
50
s and MIC
90
s, one dilution lower than those of moxifloxacin and levofloxacin. For strains for which ciprofloxacin MICs were ≥0.12 μg/ml, MIC
50
s were similar for the four quinolones tested, although garenoxacin presented the widest activity range (0.03 to 32 μg/ml) and the highest MIC at which 90% of the isolates tested were inhibited (16.0 μg/ml). For strains without amino acid changes in the quinolone resistance determining region (QRDR) of GyrA and ParC, garenoxacin MICs were ≤0.03 μg/ml; with a single amino acid change in GyrA, garenoxacin MICs were 0.06 to 0.12 μg/ml; with one amino acid change each in GyrA and ParC, garenoxacin MICs were 0.5 to 2.0 μg/ml; one amino acid change in ParC combined with two amino acid changes in GyrA increased the MICs to ≥4 μg/ml for all assayed quinolones. We conclude that garenoxacin has excellent activity against
H. influenzae
, although progressive acquired resistance was observed by step-by-step mutation in the QRDR of
gyrA
and
parC.
Related Clones Containing SCC
mec
Type IV Predominate among Clinically Significant
Staphylococcus epidermidis
Isolates
Authors: Wisplinghoff Hilmar , Rosato Adriana E. , Enright Mark C. , Noto Michael , Craig William , Archer Gordon L.
Published: October 2003

SCC
mec
is a mobile genetic element that carries the gene (
mecA
) mediating methicillin resistance in staphylococci. For
Staphylococcus aureus
, four SCC
mec
types have been described, one (type IV) of which has been associated with newly identified community-acquired methicillin-resistant
S. aureus
. However, the distribution of SCC
mec
types among
S. epidermidis
is not known. SCC
mec
typing of a collection of 44 methicillin-resistant
Staphylococcus epidermidis
(MRSE) isolates recovered between 1973 and 1983 from the blood of patients with prosthetic valve endocarditis (PVE) was performed by PCR amplification of key genetic elements (
mecA
,
mecI
, IS
1272
, and
ccrAB
). Of the 44 isolates, 1 (2%) harbored SCC
mec
type I, 15 (34%) harbored type II, 12 (28%) harbored type III, and 16 (36%) harbored type IV. The complete nucleotide sequence of SCC
mec
type IV was determined for 16 isolates and found to be identical in size (24 kb) and 98% homologous to DNA sequences published for
S. aureus
. Type IV SCC
mec
was also common (5 of 10 isolates) among a geographically dispersed collection of 10 recent (1998 to 2001)
S. epidermidis
bloodstream isolates. Multilocus sequence typing (MLST) (using the same seven genes presently employed for
S. aureus
MLST) of these MRSE isolates and of 10 additional recent geographically dispersed methicillin-susceptible isolates demonstrated that all 16 PVE isolates and 2 of 5 recent isolates harboring type IV SCC
mec
were in three related clonal groups. All three MSSE PVE isolates recovered from patients between 1976 and 1979 were in the same clonal groups as type IV SCC
mec
MRSE isolates. These data support the hypothesis of intra- and interspecies transfer of type IV SCC
mec
and suggest that there are clonal associations in
S. epidermidis
that correlate with SCC
mec
type.
Salvage Treatment with Amphotericin B in Progressive Human Alveolar Echinococcosis
Authors: Reuter Stefan , Buck Andreas , Grebe Olaf , Nüssle-Kügele Karin , Kern Peter , Manfras Burkhard J.
Published: October 2003

Most patients with alveolar echinococcosis are diagnosed at a late stage when the disease has advanced to unresectable hepatic lesions. These patients require lifelong therapy with benzimidazoles, the only medical treatment currently available. To date, no treatment option remains for patients with benzimidazole intolerance or treatment failure. Amphotericin B was recently shown to exert antiparasitic activity in vitro. Here, we report the efficacy of amphotericin B in human alveolar echinococcosis. In three patients with extensive disease and without further treatment options, disease progression had been documented over several months. They were treated with amphotericin B intravenously at a dose of 0.5 mg/kg of body weight three times per week. Follow-up parameters were physical examination, laboratory parameters, and imaging techniques. Amphotericin B treatment effectively halted parasite growth in all three patients. The antiparasitic effect was most evident by spontaneous closure of cutaneous fistulae in two patients and by constant size of parasitic lesions during treatment, as assessed radiologically. Metabolic activity in parasitic areas was visualized by positron emission tomography and significantly decreased during treatment. However, progressive affection of the heart in one patient could not be stopped. All patients currently continue on amphotericin B and have been treated for 25, 17, and 14 months, respectively. We introduce amphotericin B as salvage treatment for alveolar echinococcosis patients with intolerance or resistance to benzimidazoles, as it effectively suppresses parasite growth. Amphotericin B is not parasitocidal; therefore long-term treatment has to be anticipated.
Active Internalization of the
Penicillium chrysogenum
Antifungal Protein PAF in Sensitive Aspergilli
Authors: Oberparleiter Christoph , Kaiserer Lydia , Haas Hubertus , Ladurner Peter , Andratsch Manfred , Marx Florentine
Published: October 2003

The
Penicillium chrysogenum
antifungal protein PAF inhibits the growth of various filamentous fungi. In this study, PAF was found to localize to the cytoplasm of sensitive aspergilli by indirect immunofluorescence staining. The internalization process required active metabolism and ATP and was prevented by latrunculin B, suggesting an endocytotic mechanism.
Doxycycline Is Anti-Inflammatory and Inhibits Staphylococcal Exotoxin-Induced Cytokines and Chemokines
Authors: Krakauer Teresa , Buckley Marilyn
Published: October 2003

Proinflammatory cytokines mediate the toxic effect of superantigenic staphylococcal exotoxins (SE). Doxycycline inhibited SE-stimulated T-cell proliferation and production of cytokines and chemokines by human peripheral blood mononuclear cells. These results suggest that the antibiotic doxycycline has anti-inflammatory effects and is therapeutically useful for mitigating the pathogenic effects of SE.
Favorable Interactions between Enfuvirtide and 1-β-
d
-2,6-Diaminopurine Dioxolane In Vitro
Authors: Tremblay Cécile L. , Poulin Danielle L. , Hicks Jennifer L. , Selliah Subajini , Chamberland Annie , Giguel Françoise , Kollmann Christopher S. , Chou Ting Chao , Dong Huajin , Hirsch Martin S.
Published: October 2003

We evaluated the in vitro anti-human immunodeficiency virus type 1 (HIV-1) interactions between 1- β-
d
-2,6-diaminopurine dioxolane (DAPD) and enfuvirtide (T-20) against clinical isolates sensitive and resistant to reverse transcriptase and protease inhibitors. Interactions between T-20 and DAPD were synergistic to nearly additive, with combination index values ranging from 0.53 to 1.06 at 95% inhibitory concentrations. These studies suggest that a combination of T-20 and DAPD might be useful in the treatment of antiretroviral drug-experienced patients.