julilili42/papers huggingface dataset:
H 1504+65 – The Naked Stellar C/O Core of a Former Red Giant Observed with FUSE and Chandra
2002-01-01

Abstract H 1504+65 is an extremely hot hydrogen-deficient white dwarf with an effective temperature close to 200 000 K. We present new FUV and soft X-ray spectra obtained with FUSE and Chandra, which confirm that H1504+65 has an atmosphere primarily composed of carbon and oxygen. The Chandra spectra show a wealth of absorption lines from highly ionized oxygen, neon and magnesium and suggest relatively high Ne and Mg abundances. This corroborates an earlier suggestion that H1504+65 represents a naked C/O stellar core or even the C/O envelope of an O/Ne/Mg white dwarf.
Relaxation processes in relativistic plasma created from vacuum by a strong field
2002-01-01

We consider a relaxation process in a relativistic plasma of particles and antiparticles created from vacuum by a supercritical classical Abelian field. Quark-gluon plasma evolution is described by the kinetic equation with a source term and collisional integral in the Belyaev-Budker form with perturbative cross sections for parton scatterings. The back reaction of created partons on the generating field is taken into account. Being solved numerically, the set of equations does not result in a fast attainment of a quasi-equilibrium state for systems under discussion. To get a reasonable estimate for the relaxation time of quark-gluon plasma, one needs to increase the cross sections several times that would effectively correspond to accounting for radiative perturbative processes and scatterings of nonperturbative partons, as well.
Nominalizations
2002-01-01

The present volume is a selection of the papers presented in workshops at ZAS in Berlin in November 2000 and at theUniversity of Tübingen in April 2001, devoted to synchronic and, diachronic aspects of various types of nominalizations. Nominalization has a long history in linguistic research. Its nature can only be captured by taking into account the interface between morphology, syntax and semantics on the one hand, and the interface between semantics and conceptual structure on the other.&#x0D;
The randomized sample tree
2002-01-01

We present a new data structure for rendering highly complex virtual environments of arbitrary topology. The special feature of our approach is that it allows an interactive navigation in very large scenes (30 GB/400 million polygons in our benchmark scenes) that cannot be stored in main memory, but only on a local or remote hard disk. Furthermore, it allows interactive rendering of substantially more complex scenes by instantiating objects.For the computation of an approximate image of the scene, a sampling technique is used. In the preprocessing, a so-called sample tree is built whose nodes contain randomly selected polygons from the scene. This tree only uses space that is linear in the number of polygons. In order to produce an image of the scene, the tree is traversed and polygons stored in the visited nodes are rendered. During the interactive walkthrough, parts of the sample tree are loaded from local or remote hard disk.We implemented our algorithm in a prototypical walkthrough system. Analysis and experiments show that the quality of our images is comparable to images computed by the conventional z-buffer algorithm regardless of the scene topology.
ESTIMATION OF DISCRETE CHOICE MODELS WITH MINIMAL VARIATION OF ALTERNATIVE-SPECIFIC VARIABLES
2002-01-01

The paper states conditions for minimal variation within the explanatory variables such that the maximum likelihood estimate of the coefficient vector in the discrete choice logit model is unique. Special emphasis is given to the case that (almost) all individuals observe the same set of alternative-specific explanatory variables. The aspect of 'experimental design' in discrete choice models is discussed.
[Gunshot reconstructions based on individually parametrical 3-dimensional victim models].
2002-01-02

In cases of lethal firearm injuries computer enhanced anatomical feasibility studies can provide unambiguous clues concerning self-versus extraneous infliction. To this end individualized digital 3-dimensional geometrical models of the victim and the weapon are generated true to scale with the help of the CAD software (POSER Version 4, egi.sys AG). All anatomical data relevant to the motion apparatus and the range of movement as well as the injuries of the individual victim are carefully documented and serve as input parameters for the digital geometrical model. The bullet path is visualized as a cylinder between entrance and exit wound. A series of simulation sequences then can be carried out by the variation of anatomically possible shot positions and the virtual grasp of the weapon. An exact alignment of the firearm's barrel and the bullet path is a reliable statement for the feasibility of self-infliction. In addition to circumstantial evidence the digital reconstruction of the firearm shot admits of unambiguous conclusions about the course of the traumatic event.
Hyperfine splitting of hydrogenlike thallium
2002-01-04

The dynamic correlation model was used to calculate nuclear ground-state wave functions of and The ground states of these isotopes are characterized by strong mixing amplitudes of the valence hole with the intrinsic vacuum states (valence hole coupled to core excitations). Nuclear magnetic moments, radii, and the hyperfine-structure splitting energy for the hydrogenlike ions were calculated. Experimental magnetic moments and radii of the nuclear ground states are well reproduced. The hyperfine-structure splitting of the hydrogenlike Tl isotopes have not been measured so far, hence, the obtained values are only compared with predictions of other theoretical calculations. The difference in the hyperfine-structure splitting between and is found to be 0.026 eV, which corresponds to a 3.1 nm shift in the transiton wavelength.
ESTIMATION OF DISCRETE CHOICE MODELS WITH MINIMAL VARIATION OF ALTERNATIVE-SPECIFIC VARIABLES
2002-01-04

The paper states conditions for minimal variation within the explanatory variables such that the maximum likelihood estimate of the coefficient vector in the discrete choice logit model is unique. Special emphasis is given to the case that (almost) all individuals observe the same set of alternative-specific explanatory variables. The aspect of 'experimental design' in discrete choice models is discussed.
ChemInform Abstract: Syntheses, Crystal Structures and Magnetic Behavior of [Li(12‐crown‐4)2][Li(12‐crown‐4)OH2]2 [Nb6Cl18], [Li(15‐crown‐5)2(OH2)]3 [Nb6Cl18], and [(18‐crown‐6)2(O2H5)]3 [Nb6Cl18].
2002-01-08

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Determination of Enantiomerization Barriers by Dynamic and Stopped‐Flow Chromatographic Methods
2002-01-08

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
A new model for shallow water in the low-Rossby-number limit
2002-01-09

We revisit Salmon's ‘Dirac bracket projection’ approach to constructing generalized semi-geostrophic equations. One of the obstacles to the method's applicability is that it leads to a sign-indefinite energy functional in the computational domain. In some instances this can cause severe failure of the model. We demonstrate in the simple context of shallow-water semi-geostrophy that the Hamiltonian remains positive definite when the asymptotic expansion at the heart of this method is carried to the next order. The resulting new model can be interpreted in the framework of regularization by Lagrangian averaging, which is currently receiving much attention.
Plasmodium falciparum liver-stage antigen-1 peptide-specific interferon-gamma responses are not suppressed during uncomplicated malaria in African children.
2002-01-10

Liver-stage antigen (LSA)-1 is a candidate vaccine molecule for Plasmodium falciparum malaria, but knowledge of the evolution of naturally acquired immune responses to LSA-1 in African children is lacking. We therefore assessed cellular immune responses to two defined T cell epitopes of LSA-1, during and after uncomplicated P. falciparum malaria in a group of Gabonese children. In terms of their prevalence, interferon (IFN)-gamma responses of peripheral blood mononuclear cells (PBMC) to an LSA-1 N-terminal peptide, T1, were significantly higher when measured during the acute phase compared with convalescence. IFN-gamma responses to the LSA-J (hinge region) peptide showed a similar profile, but at a lower prevalence. Depletion experiments confirmed that CD8+ T cells are a major source of peptide-driven IFN-gamma, but both lymphoproliferation and the production of IL-10 in response to either of the peptides was low in all children at all times. PBMC from 25% of the children failed to produce IFN-gamma in response to either peptide at any time-point. The results suggest that lymphocytes producing IFN-gamma in response to at least one T cell epitope of LSA-1 are most frequent in the peripheral circulation during the acute phase of P. falciparum malaria. Thus, in this case, the generalised suppression of cell-mediated responses which characterises acute malaria does not affect liver-stage antigen-specific IFN-gamma production. These findings imply that measurements of the frequency of parasite antigen-specific cellular immune responses in clinically healthy individuals may represent significant underestimations, which has important implications for the design of field-based vaccine antigen-related studies.
Identification of known and novel immunogenic T‐cell epitopes from tumor antigens recognized by peripheral blood T cells from patients responding to IL‐2‐based treatment
2002-01-14

Abstract In previous studies CD8+ T cells specific for melanocyte antigens have been frequently found in melanoma patients responding to interleukin‐2 (IL‐2)‐based therapies. In our study we analyzed the suitability of using circulating T cells from melanoma patients with clinical response after IL‐2‐based therapy to identify novel T‐cell epitopes from defined tumor antigens. Using unstimulated peripheral blood mononuclear cells and the interferon‐γ (IFN‐γ) ELISPOT assay, we studied CD8 + T‐cell responses against 5 peptides from the tumor antigen tyrosinase (Tyr) selected by epitope prediction using an HLA‐A1‐binding computer algorithm. T cells specifically secreting IFN‐γ in response to 3 of these 5 peptides, namely, Tyr (454–463), Tyr (146–156) and Tyr (243‐251), could be detected in 4 of 4 HLA‐A1‐positive patients with clinical response. In contrast, no T‐cell responses against these peptides were seen in 6 HLA‐A1‐positive melanoma patients with progressive disease and in 8 healthy subjects. We could generate specific cytotoxic T lymphocytes (CTL) against Tyr (454–463) using peptide‐pulsed autologous dendritic cells as antigen‐presenting cells. The induced CTLs efficiently killed melanoma cells that express HLA‐A1 and tyrosinase. The peptides Tyr (146–156) and Tyr (243‐251) had recently been identified as CTL epitopes by other groups. Further ex vivo characterization of the T cells reactive against the novel epitope Tyr (454–463) in 1 patient by multicolor flow cytometry showed specific CD3+/CD8+/IFN‐γ+ T cells with frequencies of up to 0.41% of the CD3+/CD8+ T‐cell population. Most of this T‐cell population also expressed granzyme B. Our data confirm that in patients with tumor regressions induced by immunotherapy or chemoimmunotherapy circulating T cells reactive with tyrosinase epitopes can frequently be detected. Peripheral blood T cells from such patients are a valuable source for screening peptides selected by epitope prediction This strategy facilitates the rapid identification of immunogenic T‐cell epitopes that are probable targets of immune‐mediated tumor rejection. © 2002 Wiley‐Liss, Inc.
Intracellular Concentration Measurements in Adherent Cells: A Comparison of Import Efficiencies of Cell-Permeable Peptides
2002-01-15

A protocol was developed for performing intracellular concentration measurements in flat adherent tissue culture cells by fluorescence correlation microscopy (FCM). Determination of the number of molecules in the confocal detection volume had to account for background fluorescence caused by molecules adsorbed to the surface of the measurement chamber. Such a background signal leads to a decrease in the amplitude of the autocorrelation function, and thereby to the calculation of an erroneously high number of molecules. Because of the spatial heterogeneity of the background intensity, a method was devised by which its contribution to the total fluorescence could be determined directly from each individual autocorrelation measurement. This method was applied to a comparison of the import efficiencies of different cell-permeable peptides at nanomolar concentrations. The Antennapedia homeodomain-derived peptide penetratin was imported about three times as efficient as the basic fibroblast growth factor-derived MTS peptide. Both peptides equilibrated between cytoplasm and nucleus. A relatively high mobility of these molecules inside the cells indicated that they may be rapidly degraded by cytosolic proteases. Based on these results, it will be possible to determine intracellular concentrations of inhibitors linked to import peptides directly by FCM at nanomolar concentrations and to optimise such constructs for proteolytic stability.
Electromagnetic couplings of the chiral perturbation theory Lagrangian from the perturbative chiral quark model
2002-01-15

We apply the perturbative chiral quark model to the study of the low-energy pi-N interaction. Using an effective chiral Lagrangian we reproduce the Weinberg-Tomozawa result for the S-wave pi-N scattering lengths. After inclusion of the photon field we give predictions for the electromagnetic O(p^2) low-energy couplings of the chiral perturbation theory effective Lagrangian that define the electromagnetic mass shifts of nucleons and first-order (e^2) radiative corrections to the pi-N scattering amplitude. Finally, we estimate the leading isospin-breaking correction to the strong energy shift of the pi(-)p atom in the 1s state, which is relevant for the experiment "Pionic Hydrogen" at PSI.
Equilibrium abundances in hot DA white dwarfs \\n as derived from self-consistent diffusion models
2002-01-15

\\n \\n We present the first analysis of an EUV selected sample of hot DA\\n white dwarfs using a new type of atmospheric models. These models take\\n into account the interplay between gravitational settling and\\n radiative acceleration to predict the chemical stratification from an\\n equilibrium between the two forces while self-consistently solving for\\n the atmospheric structure. In contrast to atmospheric models with the\\n assumption of chemical homogeneity, the number of free parameters in\\n the new models is reduced to the effective temperature and surface\\n gravity alone. The overall good reproduction of observed EUV spectra\\n reveals that these models are able to describe the physical conditions\\n in hot DA white dwarf atmospheres correctly. A comparison with\\n previous analyses highlights the improvements as well as the limits of\\n our new models.\\n \\n \\n
Label-Free Parallel Screening of Combinatorial Triazine Libraries Using Reflectometric Interference Spectroscopy
2002-01-18

The parallel reflectometric interference spectroscopy is presented as a label-free optical detection method. A new setup was adapted to accommodate sample carriers in a 96-well microplate. It allows for the first time simultaneous plate imaging by a CCD camera for the parallel detection of specific biomolecular interaction in the microplate wells at heterogeneous phase using direct optical monitoring. The detection of binding events with time resolution enables a highly parallel functional biomolecular interaction analysis (BIA). The combination of this new screening setup with combinatorial solid-phase synthesis is performed in the wells of glass-bottom microplates to accomplish the synthesis and the screening platform within one device. As a model system for a solid-phase substance library, synthesis of a triazine library and the subsequent BIA with four different antibodies were carried out. The presented setup enables a time resolution of 18 s with a total screening time of less than 35 min including baseline adjustment, BIA, and regeneration of the screening device for 96 samples in parallel. The binding studies reveal a fast classification of the different monoclonal and polyclonal antibodies and enable the detection of triazines with high binding affinity. The presented prototype is the first parallelized optical label-free detection system for biomolecular interaction analysis that is suitable for a high-throughput screening based on the 96-well microplate format.
ChemInform Abstract: Total Synthesis and Anti‐Leishmanial Activity of (R)‐(‐)‐Argentilactone.
2002-01-22

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Synthesis of the Core Structure of Apicularen A by Transannular Cyclization
2002-01-24

[reaction: see text] An approach to the macrocyclic core of apicularen A is described. Thus, cross-coupling of the aryl triflate 7 with the vinylstannane 19 provided the styrene 20. Deprotection led to the dihydroxy acid 22. Through a size-selective macrolactonization, the 12-membered macrolactone 23 was obtained. Treatment of 24 with N-phenyl selenophthalimide gave the desired trans-pyran 24. This approach might parallel the biosynthetic pathway.
Modulated magnetic ordering in the Cu-doped pseudoperovskite system CaCuxMn3-xMn4O12
2002-01-25

The crystal and magnetic structures of the CaCuxMn3-xMn4O12 compounds with x = 0.3 and 0.7 were investigated by means of x-ray and neutron powder diffraction. The crystal structure parameters of the x = 0.3 compound at 60 K have been refined within the trigonal space group R. The magnetic moments of Mn ions in the x = 0.3 sample become ordered below 40 K. The magnetic ordering is modulated with a propagation vector (0,0,κ). A model of the magnetic structure which is in agreement with the experimental data is proposed along with an estimation of the temperature dependence of the magnetic moment value. The magnetic ordering has a reduced correlation length of about 250 Å. The x = 0.7 compound does not show any long-range magnetic ordering down to 1.5 K.
ChemInform Abstract: Synthesis, Absorption and Luminescence of a New Series of Soluble Distyrylbenzenes (I) and (II) Featuring Cyano Substituents at the Peripheral Rings.
2002-01-29

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
German Cancer Society Neuro‐Oncology Working Group NOA‐03 multicenter trial of single‐agent high‐dose methotrexate for primary central nervous system lymphoma
2002-01-31

Abstract The prospective multicenter NOA‐03 trial, conducted by the Neuro‐Oncology Working Group (NOA) of the German Cancer Society, was initiated to define the feasibility and efficacy of single‐agent high‐dose methotrexate therapy without concomitant radiotherapy in immunocompetent patients with primary central nervous system lymphoma. Thirty‐seven patients (median age, 60 years) received 179 biweekly courses of 8g/m 2 methotrexate. Response was assessed after 3 and 6 courses. We had planned to enter 105 patients into the trial. Since fewer than the projected 18 of 37 patients achieved a complete response after an intermediate analysis, the trial was closed. In intention‐to‐treat analysis, 11 of 37 patients (29.7%) achieved complete response, whereas 14 of 37 patients (37.8%) were found to have progressive disease. The median relapse‐free survival among complete response patients was 13.7 months. Multivariate logistic regression analysis revealed that corticosteroid application during the first methotrexate course was associated with complete response. The regimen was well tolerated, but, unlike previously reported results, the activity of high‐dose methotrexate was only moderate.
Effects of reduced mucus oxygen concentration in airway Pseudomonas infections of cystic fibrosis patients
2002-02-01

Current theories of CF pathogenesis predict different predisposing "local environmental" conditions and sites of bacterial infection within CF airways. Here we show that, in CF patients with established lung disease, Pseudomonas aeruginosa was located within hypoxic mucopurulent masses in airway lumens. In vitro studies revealed that CF-specific increases in epithelial O(2) consumption, linked to increased airway surface liquid (ASL) volume absorption and mucus stasis, generated steep hypoxic gradients within thickened mucus on CF epithelial surfaces prior to infection. Motile P. aeruginosa deposited on CF airway surfaces penetrated into hypoxic mucus zones and responded to this environment with increased alginate production. With P. aeruginosa growth in oxygen restricted environments, local hypoxia was exacerbated and frank anaerobiosis, as detected in vivo, resulted. These studies indicate that novel therapies for CF include removal of hypoxic mucus plaques and antibiotics effective against P. aeruginosa adapted to anaerobic environments.
Effects of reduced mucus oxygen concentration in airway Pseudomonas infections of cystic fibrosis patients
2002-02-01

Current theories of CF pathogenesis predict different predisposing “local environmental” conditions and sites of bacterial infection within CF airways. Here we show that, in CF patients with established lung disease, Psuedomonas aeruginosa was located within hypoxic mucopurulent masses in airway lumens. In vitro studies revealed that CF-specific increases in epithelial O2 consumption, linked to increased airway surface liquid (ASL) volume absorption and mucus stasis, generated steep hypoxic gradients within thickened mucus on CF epithelial surfaces prior to infection. Motile P. aeruginosa deposited on CF airway surfaces penetrated into hypoxic mucus zones and responded to this environment with increased alginate production. With P. aeruginosa growth in oxygen restricted environments, local hypoxia was exacerbated and frank anaerobiosis, as detected in vivo, resulted. These studies indicate that novel therapies for CF include removal of hypoxic mucus plaques and antibiotics effective against P. aeruginosa adapted to anaerobic environments.