bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular and Enzymatic Characterization of the Porcine Endogenous Retrovirus Protease
Authors: Blusch Jürgen H. , Seelmeir Sigrid , von der Helm Klaus 
Published: July 2002

ABSTRACT

The protease of the porcine endogenous retrovirus (PERV) subtypes A/B and C was recombinantly expressed in
Escherichia coli
as proteolytically active enzyme and characterized. The PERV Gag precursor was also recombinantly produced and used as the substrate in an in vitro enzyme assay in parallel with synthetic nonapeptide substrates designed according to cleavage site sequences identified in the PERV Gag precursor. The proteases of all PERV subtypes consist of 127 amino acid residues with an
M
r
of 14,000 as revealed by determining the protease N and C termini. The PERV proteases have a high specificity for PERV substrates and do not cleave human immunodeficiency virus (HIV)-specific substrates, nor are they inhibited by specific HIV protease inhibitors. Among the known retroviral proteases, the PERV proteases resemble most closely the protease of the murine leukemia retrovirus.
Identification of Two Additional Translation Products from the Matrix (M) Gene That Contribute to Vesicular Stomatitis Virus Cytopathology
Authors: Jayakar Himangi R. , Whitt Michael A. 
Published: July 2002

ABSTRACT
The matrix (M) protein of vesicular stomatitis virus (VSV) is a multifunctional protein that is responsible for condensation of the ribonucleocapsid core during virus assembly and also plays a critical role in virus budding. The M protein is also responsible for most of the cytopathic effects (CPE) observed in infected cells. VSV CPE include inhibition of host gene expression, disablement of nucleocytoplasmic transport, and disruption of the host cytoskeleton, which results in rounding of infected cells. In this report, we show that the VSV M gene codes for two additional polypeptides, which we have named M2 and M3. These proteins are synthesized from downstream methionines in the same open reading frame as the M protein (which we refer to here as M1) and lack the first 32 (M2) or 50 (M3) amino acids of M1. Infection of cells with a recombinant virus that does not express M2 and M3 (M33,51A) resulted in a delay in cell rounding, but virus yield was not affected. Transient expression of M2 and M3 alone caused cell rounding similar to that with the full-length M1 protein, suggesting that the cell-rounding function of the M protein does not require the N-terminal 50 amino acids. To determine if M2 and M3 were sufficient for VSV-mediated CPE, both M2 and M3 were expressed from a separate cistron in a VSV mutant background that readily establishes persistent infections and that normally lacks CPE. Infection of cells with the recombinant virus that expressed M2 and M3 resulted in cell rounding indistinguishable from that with the wild-type recombinant virus. These results suggest that M2 and M3 are important for cell rounding and may play an important role in viral cytopathogenesis. To our knowledge, this is first report of the multiple coding capacities of a rhabdovirus matrix gene.
Alpha Interferon Inhibits Hepatitis C Virus Replication in Primary Human Hepatocytes Infected In Vitro
Authors: Castet Valérie , Fournier Chantal , Soulier Alexandre , Brillet Rozenn , Coste Joliette , Larrey Dominique , Dhumeaux Daniel , Maurel Patrick , Pawlotsky Jean-Michel 
Published: July 2002

ABSTRACTChronic hepatitis C is a common cause of liver disease, the complications of which include cirrhosis and hepatocellular carcinoma. Treatment of chronic hepatitis C is based on the use of alpha interferon (IFN-α). Recently, indirect evidence based on mathematical modeling of hepatitis C virus (HCV) dynamics during human IFN-α therapy suggested that the major initial effect of IFN-α is to block HCV virion production or release. Here, we used primary cultures of healthy, uninfected human hepatocytes to show that: (i) healthy human hepatocytes can be infected in vitro and support HCV genome replication, (ii) hepatocyte treatment with IFN-α results in expression of IFN-α-induced genes, and (iii) IFN-α inhibits HCV replication in infected human hepatocytes. These results show that IFN-α acts primarily through its nonspecific antiviral effects and suggest that primary cultures of human hepatocytes may provide a good model to study intrinsic HCV resistance to IFN-α.
Cancer mortality among man-made graphite electrode manufacturing workers: results of a 38 year follow up
Authors: Mori I 
Published: July 2002

Background and Aims:To examine the risk for cancer mortality among workers exposed to coal tar and coal tar pitch volatiles in a man-made graphite electrode factory. The risk for cancer mortality in this type of factory is still inconclusive, although coal tar and coal tar pitch are recognised as human carcinogens.Methods:The study cohort consisted of 332 male employees who served more than five years in the period 1951–74. The cohort was traced until 1988. Analyses used standardised mortality ratios (SMRs) to compare cause specific mortality with that in the general and local population. Effect of smoking was estimated based on the information collected from the subgroup of the cohort. SMRs for leading causes of death were compared among different job titles, duration of employment, time since first employment, and observation subperiods. Exposure level for tar and benzo[a]pyrene (BaP) in the factory was also discussed, based on measurements done by other researchers in the past.Results:During the study period, 52 deaths were identified (SMR 0.68), including 22 cancer deaths (SMR 1.01). The SMR for lung cancer was significantly increased in comparison with the general population (SMR 2.62). It was slightly decreased in comparison with the local population, but remained significant (SMR 2.35). Excess deaths were also observed for lymphatic and haematopoietic cancers (SMR 3.46). Smoking habits in the subgroup were similar to those in the general population; thus the increased SMR for lung cancer was unlikely to be explained by smoking.Conclusion:Previous environmental measurements suggested that considerable exposure to tar and BaP had existed in the factory. The results suggest a possible risk for lung cancer among the cohort, but the limitations of the study, such as the small study population and insufficient information on exposure, indicate that further study is required.
Early diagnosis of colonic carcinoma: a haemorrhagic complication after the use of tissue plasminogen activator
Authors: Baker J W , Mitchell S J , Dixon A R 
Published: July 2002

Abstract
Haemorrhagic complications of thrombolytic therapy for myocardial infarction are common. A 68 year old man presented with a myocardial infarction and was started on tissue plasminogen activator. Soon after he experienced rectal bleeding and a barium enema showed a small carcinoma in the colon, which was treated surgically. It is important that gastrointestinal bleeding secondary to thrombolysis is always investigated for an underlying cause.
Formulation of particle pseudo-rapidity (rapidity) distribution in high-energy pp collision and e+e annihilation
Authors: Liu F -H 
Published: July 2002

The pseudorapidity (rapidity) distributions of particles produced in high-energy collisions are analyzed using the revised thermalized cylinder model. The calculated results are compared and found to be in agreement with the experimental data of pp collision and e+e annihilation. PACS Nos.: 13.85-t, 13.75-n, 13.85Hd, 13.65+i
Iterative solutions for relativistic dissipative cosmologies
Authors: Harko T , Mak M K 
Published: July 2002

Iterative solutions of the gravitational field equations for a homogeneous flat FriedmannRobertsonWalker Universe filled with a causal bulk viscous fluid in the framework of the full IsraelStewartHiscock theory are presented. The general solution of the field equations are presented in a parametric form in the zeroth-, first-, second-, and mth-order approximation by the method of iteration. The time evolution of the scale factor, energy density, deceleration parameter, entropy, Kretschmann scalar, and bulk viscous pressure-thermodynamic pressure ratio for a Zeldovich fluid-filled space-time are discussed. PACS Nos.: 98.80-k, 04.20Jb
The impact of the OSIRIS grating efficiency on radiance and trace-gas retrievals
Authors: McLinden C A , McConnell J C , Strong K , McDade I C , Gattinger R L , King R , Solheim B , Llewellyn E J , Evans W JF 
Published: July 2002

The optical spectrograph and infrared imaging system (OSIRIS), launched in 2001, is a UVvisible diffraction-grating instrument designed to measure light scattered from the Earth's limb. Laboratory measurements of the OSIRIS diffraction-grating efficiency reveal a sensitivity to polarization including an anomalous structure of width 2030 nm introduced into light polarized in a direction perpendicular to the grooves of the grating. A vector radiative-transfer model was used to generate synthetic OSIRIS spectra in an effort to examine the effect of this on radiances and trace-gas retrievals. Radiances that included grating effects were found to deviate by nearly 10% from those that did not and also contained the anomalous structure. Performing differential optical absorption spectroscopy (DOAS) on these spectra revealed errors in ozone apparent column densities of up to 80 DU. The size of the error was controlled mainly by the difference in polarization between the two DOAS spectra. Two possible correction methods were investigated. The first was to remove the grating effects by applying a correction factor to the raw radiances calculated using the vector radiative-transfer model. The second was to include the efficiency coefficient spectra in the DOAS fit. PACS Nos.: 42.68Mj, 98.55Qf
Retrieval of vertical concentration profiles from OSIRIS UVvisible limb spectra
Authors: Strong K , Joseph B M , Dosanjh R , McDade I C , McLinden C A , McConnell J C , Stegman J , Murtagh D P , Llewellyn E J 
Published: July 2002

The OSIRIS instrument, launched on the Odin satellite in February 2001, includes an optical spectrograph that will record UVvisible spectra of sunlight scattered from the limb over a range of tangent heights. These spectra will be used to retrieve vertical profiles of ozone, NO2, OClO, BrO, NO3, O2, and aerosols, for the investigation of both stratospheric and mesospheric processes, particularly those related to ozone chemistry. In this work, the retrieval of vertical profiles of trace-gas concentrations from OSIRIS limb-radiance spectra is described. A forward model has been developed to simulate these spectra, and it consists of a single-scattering radiative-transfer model with partial spherical geometry, trace-gas absorption, Mie scattering by stratospheric aerosols, a Lambertian surface contribution, and OSIRIS instrument response and noise. Number-density profiles have been retrieved by using optimal estimation (OE) to combine an a priori profile with the information from sets of synthetic ``measurements''. For ozone, OE has been applied both to limb radiances at one or more discrete wavelengths and to effective-column abundances retrieved over a broad spectral range using differential optical absorption spectroscopy (DOAS). The results suggest that, between 15 and 35 km, ozone number densities can be retrieved to 10% accuracy or better on 1 and 2 km grids and to 5% on a 5 km grid. The combined DOAS-OE approach has also been used to retrieve NO2 number densities, yielding 13% accuracy or better for altitudes from 18 to 36 km on a 2 km grid. Differential optical absorption spectroscopy  optimal estimation retrievals of BrO and OClO reproduce the true profiles above 15 km in the noise-free case, but the quality of the retrievals is highly sensitive to noise on the simulated OSIRIS spectra because of the weak absorption of these two gases. The development of inversion methods for the retrieval of trace-gas concentrations from OSIRIS spectra is continuing, and a number of future improvements to the forward model and refinements of the retrieval algorithms are identified. PACS Nos.: 42.68Mj, 94.10Dy
A vector radiative-transfer model for the Odin/OSIRIS project
Authors: McLinden C A , McConnell J C , Griffioen E , McElroy C T 
Published: July 2002

A vector radiative-transfer code has been developed that is able to accurately and efficiently calculate radiance and polarization scattered from Earth's limb. A primary application of this code will be towards generating weighting functions, based on calculated limb radiances, for the retrieval of trace gases (O3, NO2, BrO, OClO, and O4) from the optical spectrograph and infrared imaging system (OSIRIS). OSIRIS is a UVvisible instrument on board the Odin satellite that measures limb-scattered light. This model solves the vector radiative-transfer equation using an iterative technique simultaneously in both plane-parallel and spherical-shell atmospheres. OSIRIS simulated limb radiance and polarization and OSIRIS weighting functions are presented along with a discussion of the numerical solution parameters, model intercomparisons and timings, and necessary model improvements. Overall agreement with other models was found to be very good and model speed is comparable to a fast finite-difference code. A set of OSIRIS reference atmospheres have been compiled for use with radiative-transfer models. Each of the 216 atmospheres (18 latitudes × 12 months) include profiles of air, pressure, temperature, ozone, NO2, BrO, and stratospheric aerosols. PACS Nos.: 42.68-w, 94.10Gb
Studies for the Odin sub-millimetre radiometer: I. Radiative transfer and instrument simulation
Authors: Eriksson P , Merino F , Murtagh D , Baron P , Ricaud P , Noë J de la 
Published: July 2002

The Odin satellite mission will include radiometric measurements of the Earth's atmosphere in a limb-sounding mode, using frequencies between 480 and 580 GHz, with the overall aim of retrieving vertical distributions of atmospheric constituents. The current paper, being one of a three-part series, addresses primarily the modelling of atmospheric radiative transfer and the effect of instrumental properties: the forward model. Such a model is required for the retrieval process and this presentation puts emphasis on refraction, sensor characteristics, systematic model errors, and some implementation aspects. Refraction must be considered below about 15 km and an efficient algorithm to include this effect is presented. Sensor parts treated are the antenna, the side-band filter, and the spectrometer. The forward model is also essential for determining the needed weighting functions. A semi-analytical expression for species-abundance weighting functions is derived. To form a common basis for the article series, a comprehensive formalism is reviewed and general issues, such as the separation between fixed and variable uncertainties, discussed. As a complement to the theoretical characterization, limited to linear situations, the possibility of using repeated simulations is also described. PACS Nos.: 42.68A, 07.07D, 07.57K
Exact Results for Highly Correlated Electron Systems in One Dimension
Authors: Schlottmann P. 
Published: July 2002

One-dimensional conductors are a long-standing topic of research with direct applications to organic conductors and mesoscopic rings. The discovery of the ceramic high-temperature superconductors has revitalized the interest in low-dimensional charge and spin fluctuations of highly correlated electron systems. Several mechanisms proposed to explain the high-T c superconductors invoke properties of the two-dimensional Hubbard model, but probably also some one-dimensional aspects are relevant. Numerous one-dimensional models for correlated electrons have been studied with various approximate, asymptotically exact and exact methods. These results lead to the concept of Luttinger liquid for interacting electron gases without excitation gaps (metallic systems). Characteristic of Luttinger liquids are the charge and spin separation, marginal Fermi liquid properties, e.g. the absence of quasiparticles in the vicinity of the Fermi surface, nonuniversal power-law singularities in the one-particle spectral function and the related absence of a discontinuity in the momentum distribution at the Fermi level, the power-law decay of correlation functions for long times and large distances, persistent currents in finite rings, etc. Due to the peculiarities of the phase space in one dimension some of the models have sufficient conserved currents to be completely integrable. We review exact results derived within the framework of Bethe's ansatz for integrable one-dimensional models of correlated electrons. The Bethe-ansatz method is presented by explicitly showing the steps leading to the solution of the N-component electron gas interacting via a δ-function potential (repulsive and attractive interaction), which is probably the simplest model of correlated electrons. Emphasis is given to the procedure to extract the groundstate properties, the classification of states, the excitation spectrum, the thermodynamics and finite size effects, such as critical exponents of correlation functions and persistent currents. The method is then applied to numerous other models, e.g. (i) a two-band model involving attractive and repulsive potentials and crystalline fields splitting the bands, (ii) the traditional Hubbard chain with attractive and repulsive U, (iii) the degenerate Hubbard model with repulsive U, which displays a metal–insulator transition at a finite U, (iv) a two-band Hubbard model with repulsive U, (v) the traditional supersymmetric t–J model (vi) a two-band supersymmetric t–J model with band-splitting and (vii) the N-component supersymmetric t–J model. Finally, results for models with long-range interactions, in particular r-2 and sinh -2(r) potentials, are briefly reviewed.
NONLINEAR SIGNAL CLASSIFICATION
Authors: RAPP P. E. , WATANABE T. A. A. , FAURE P. , CELLUCCI C. J. 
Published: July 2002

In this contribution, we show that the incorporation of nonlinear dynamical measures into a multivariate discrimination provides a signal classification system that is robust to additive noise. The signal library was composed of nine groups of signals. Four groups were generated computationally from deterministic systems (van der Pol, Lorenz, Rössler and Hénon). Four groups were generated computationally from different stochastic systems. The ninth group contained inter-decay interval sequences from radioactive cobalt. Two classification criteria (minimum Mahalanobis distance and maximum Bayesian likelihood) were tested. In the absence of additive noise, no errors occurred in a within-library classification. Normally distributed random numbers were added to produce signal to noise ratios of 10, 5 and 0 dB. When the minimum Mahalanobis distance was used as the classification criterion, the corresponding error rates were 2.2%, 4.4% and 20% (Expected Error Rate = 89%). When Bayesian maximum likelihood was the criterion, the error rates were 1.1%, 4.4% and 21% respectively. Using nonlinear measures an effective discrimination can be achieved in cases where spectral measures are known to fail. Most classification errors occurred at low signal to noise ratios when a stochastic signal was misclassified into a different group of stochastic signals. When the within-library classification exercise is limited to the four groups of deterministic signals, no classification errors occurred with clean data, at SNR = 10 dB, or at SNR = 5 dB. A single classification error (Observed Error Rate = 2.5%, Expected Error Rate = 75%) occurred with both classification criteria at SNR = 0 dB.
Speed-Dependent Treadmill Training in Ambulatory Hemiparetic Stroke Patients
Authors: Pohl Marcus , Mehrholz Jan , Ritschel Claudia , Rückriem Stefan 
Published: July 2002

Background and Purpose—A new gait training strategy for patients with stroke seeks to increase walking speed through treadmill training. This study compares the effects of structured speed-dependent treadmill training (STT) (with the use of an interval paradigm to increase the treadmill speed stepwise according to principles of sport physiology) with limited progressive treadmill training (LTT) and conventional gait training (CGT) on clinical outcome measures for patients with hemiparesis.Methods—Sixty ambulatory poststroke patients were each randomly selected to receive 1 of the 3 different gait therapies: 20 subjects were treated with STT, 20 subjects were trained to walk on a treadmill with a 20% increase of belt speed over the treatment period (LTT), and 20 subjects were treated with CGT. Treatment outcomes were assessed on the basis of overground walking speed, cadence, stride length, and Functional Ambulation Category scores.Results—After a 4-week training period, the STT group scored significantly higher than the LTT and CGT groups for overground walking speed (STT versus LTT,P<0.001; STT versus CGT,P<0.001), cadence (STT versus LTT,P=0.007; STT versus CGT,P<0.001), stride length (STT versus LTT,P<0.001; STT versus CGT,P<0.001), and Functional Ambulation Category scores (STT versus LTT,P=0.007; STT versus CGT,P<0.001).Conclusions—Structured STT in poststroke patients resulted in better walking abilities than LTT or CGT. This gait training strategy provides a dynamic and integrative approach for the treatment of gait dysfunction after stroke.
Visualizing the Neural Bases of a Disconnection Syndrome with Diffusion Tensor Imaging
Authors: Molko N. , Cohen L. , Mangin J. F. , Chochon F. , Lehéricy S. , Bihan D. Le , Dehaene S. 
Published: July 2002

Abstract
Disconnection syndromes are often conceptualized exclusively within cognitive box-and-arrow diagrams unrelated to brain anatomy. In a patient with alexia in his left visual field resulting from a posterior callosal lesion, we illustrate how diffusion tensor imaging can reveal the anatomical bases of a disconnection syndrome by tracking the degeneration of neural pathways and relating it to impaired fMRI activations and behavior. Compared to controls, an abnormal pattern of brain activity was observed in the patient during word reading, with a lack of activation of the left visual word form area (VWFA) by left-hemifield words. Statistical analyses of diffusion images revealed a damaged fiber tract linking the left ventral occipito-temporal region to its right homolog across the lesioned area of corpus callosum and stopping close to the areas found active in fMRI. The behavioral disconnection syndrome could, thus, be related functionally to abnormal fMRI activations and anatomically to the absence of a connection between those activations. The present approach, based on the “negative tracking” of degenerated bundles, provides new perspectives on the understanding of human brain connections and disconnections.