216 research outputs found
Particle-hole state densities with non-equidistant single-particle levels
The correct use of energy-dependent single-particle level (s.p.l.) densities
within particle-hole state densities based on the equidistant spacing model
(ESM) is analysed. First, an analytical expression is obtained following the
convolution of energy-dependent excited-particle and hole densities. Next, a
comparison is made with results of the ESM formula using average s.p.l.
densities for the excited particles and holes, respectively. The Fermi-gas
model (FGM) s.p.l. densities calculated at the corresponding average excitation
energies are used in both cases. The analysis concerns also the density of
particle-hole bound states. The pairing correlations are taken into account
while the comparison of various effects includes the exact correction for the
Pauli exclusion principle. Quantum-mechanical s.p.l. densities and the
continuum effect can also match a corresponding FGM formula, suitable for use
within the average energy-dependent partial state density in multistep reaction
models.Comment: 29 pages, ReVTeX, 11 postscript figures, submitted to Phys.Rev.
Proton inelastic scattering to continuum studied with antisymmetrized molecular dynamics
Intermediate energy (p,px) reaction is studied with antisymmetrized
molecular dynamics (AMD) in the cases of Ni target with MeV
and C target with 200 and 90 MeV. Angular distributions for
various energies are shown to be reproduced well without any
adjustable parameter, which shows the reliability and usefulness of AMD in
describing light-ion reactions. Detailed analyses of the calculations are made
in the case of Ni target and following results are obtained: Two-step
contributions are found to be dominant in some large angle region and to be
indispensable for the reproduction of data. Furthermore the reproduction of
data in the large angle region \theta \agt 120^\circ for = 100 MeV
is shown to be due to three-step contributions. Angular distributions for
E_{p'} \agt 40 MeV are found to be insensitive to the choice of different
in-medium nucleon-nucleon cross sections and the reason of this
insensitivity is discussed in detail. On the other hand, the total reaction
cross section and the cross section of evaporated protons are found to be
sensitive to . In the course of the analyses of the calculations,
comparison is made with the distorted wave approach.Comment: 16 pages, 7 Postscript figure
Highly deformed Ca configurations in Si + C
The possible occurrence of highly deformed configurations in the Ca
di-nuclear system formed in the Si + C reaction is investigated
by analyzing the spectra of emitted light charged particles. Both inclusive and
exclusive measurements of the heavy fragments (A 10) and their
associated light charged particles (protons and particles) have been
made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding
energies of Si) = 112 MeV and 180 MeV by using the {\sc ICARE}
charged particle multidetector array. The energy spectra, velocity
distributions, and both in-plane and out-of-plane angular correlations of light
charged particles are compared to statistical-model calculations using a
consistent set of parameters with spin-dependent level densities. The analysis
suggests the onset of large nuclear deformation in Ca at high spin.Comment: 33 pages, 11 figure
Prognostic value and kinetics of circulating endothelial cells in patients with recurrent glioblastoma randomised to bevacizumab plus lomustine, bevacizumab single agent or lomustine single agent. A report from the Dutch Neuro-Oncology Group BELOB trial
Background:Angiogenesis is crucial for glioblastoma growth, and anti-vascular endothelial growth factor agents are widely used in recurrent glioblastoma patients. The number of circulating endothelial cells (CECs) is a surrogate marker for endothelial damage. We assessed their kinetics and explored their prognostic value in patients with recurrent glioblastoma.Methods:In this side study of the BELOB trial, 141 patients with recurrent glioblastoma were randomised to receive single-agent bevacizumab or lomustine, or bevacizumab plus lomustine. Before treatment, after 4 weeks and after 6 weeks of treatment, CECs were enumerated.Results:The number of CECs increased during treatment with bevacizumab plus lomustine, but not during treatment in the single-agent arms. In patients treated with lomustine single agent, higher absolute CEC numbers after 4 weeks (log 10 CEC hazard ratio (HR) 0.41, 95% CI 0.18-0.91) and 6 weeks (log 10 CEC HR 0.16, 95% CI 0.05-0.56) of treatment were associated with improved overall survival (OS). Absolute CEC numbers in patients receiving bevacizumab plus lomustine or bevacizumab single agent were not associated wit
Spallation reactions. A successful interplay between modeling and applications
The spallation reactions are a type of nuclear reaction which occur in space
by interaction of the cosmic rays with interstellar bodies. The first
spallation reactions induced with an accelerator took place in 1947 at the
Berkeley cyclotron (University of California) with 200 MeV deuterons and 400
MeV alpha beams. They highlighted the multiple emission of neutrons and charged
particles and the production of a large number of residual nuclei far different
from the target nuclei. The same year R. Serber describes the reaction in two
steps: a first and fast one with high-energy particle emission leading to an
excited remnant nucleus, and a second one, much slower, the de-excitation of
the remnant. In 2010 IAEA organized a worskhop to present the results of the
most widely used spallation codes within a benchmark of spallation models. If
one of the goals was to understand the deficiencies, if any, in each code, one
remarkable outcome points out the overall high-quality level of some models and
so the great improvements achieved since Serber. Particle transport codes can
then rely on such spallation models to treat the reactions between a light
particle and an atomic nucleus with energies spanning from few tens of MeV up
to some GeV. An overview of the spallation reactions modeling is presented in
order to point out the incomparable contribution of models based on basic
physics to numerous applications where such reactions occur. Validations or
benchmarks, which are necessary steps in the improvement process, are also
addressed, as well as the potential future domains of development. Spallation
reactions modeling is a representative case of continuous studies aiming at
understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie
Water quality and planktonic microbial assemblages of isolated wetlands in an agricultural landscape
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Wetlands 31 (2011): 885-894, doi:10.1007/s13157-011-0203-6.Wetlands provide ecosystem services including flood protection, water quality
enhancement, food chain support, carbon sequestration, and support regional biodiversity.
Wetlands occur in human-altered landscapes, and the ongoing ability of these wetlands to
provide ecosystem services is lacking. Additionally, the apparent lack of connection of some
wetlands, termed geographically isolated, to permanent waters has resulted in little regulatory
recognition. We examined the influence of intensive agriculture on water quality and planktonic
microbial assemblages of intermittently inundated wetlands. We sampled 10 reference and 10
agriculturally altered wetlands in the Gulf Coastal Plain of Georgia. Water quality measures
included pH, alkalinity, dissolved organic carbon, nutrients (nitrate, ammonium, and phosphate),
and filterable solids (dry mass and ash-free dry mass). We measured abundance and relative size
distribution of the planktonic microbial assemblage (< 45 μm) using flow cytometry. Water
quality in agricultural wetlands was characterized by elevated nutrients, pH, and suspended
solids. Autotrophic microbial cells were largely absent from both wetland types. Heterotrophic microbial abundance was influenced by nutrients and suspended matter concentration.
Agriculture caused changes in microbial assemblages forming the base of wetland food webs.
Yet, these wetlands potentially support important ecological services in a highly altered
landscape.Funding was provided by the Joseph W.
Jones Ecological Research Center.2012-07-2
Use of cancer-specific yeast-secreted in vivo biotinylated recombinant antibodies for serum biomarker discovery
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
An agent-based model of the response to angioplasty and bare-metal stent deployment in an atherosclerotic blood vessel
Purpose: While animal models are widely used to investigate the development of restenosis in blood vessels following an intervention, computational models offer another means for investigating this phenomenon. A computational model of the response of a treated vessel would allow investigators to assess the effects of altering certain vessel- and stent-related variables. The authors aimed to develop a novel computational model of restenosis development following an angioplasty and bare-metal stent implantation in an atherosclerotic vessel using agent-based modeling techniques. The presented model is intended to demonstrate the body's response to the intervention and to explore how different vessel geometries or stent arrangements may affect restenosis development. Methods: The model was created on a two-dimensional grid space. It utilizes the post-procedural vessel lumen diameter and stent information as its input parameters. The simulation starting point of the model is an atherosclerotic vessel after an angioplasty and stent implantation procedure. The model subsequently generates the final lumen diameter, percent change in lumen cross-sectional area, time to lumen diameter stabilization, and local concentrations of inflammatory cytokines upon simulation completion. Simulation results were directly compared with the results from serial imaging studies and cytokine levels studies in atherosclerotic patients from the relevant literature. Results: The final lumen diameter results were all within one standard deviation of the mean lumen diameters reported in the comparison studies. The overlapping-stent simulations yielded results that matched published trends. The cytokine levels remained within the range of physiological levels throughout the simulations. Conclusion: We developed a novel computational model that successfully simulated the development of restenosis in a blood vessel following an angioplasty and bare-metal stent deployment based on the characteristics of the vessel crosssection and stent. A further development of this model could ultimately be used as a predictive tool to depict patient outcomes and inform treatment options. © 2014 Curtin, Zhou
UVA/UVA1 phototherapy and PUVA photochemotherapy in connective tissue diseases and related disorders: a research based review
BACKGROUND: Broad-band UVA, long-wave UVA1 and PUVA treatment have been described as an alternative/adjunct therapeutic option in a number of inflammatory and malignant skin diseases. Nevertheless, controlled studies investigating the efficacy of UVA irradiation in connective tissue diseases and related disorders are rare. METHODS: Searching the PubMed database the current article systematically reviews established and innovative therapeutic approaches of broad-band UVA irradiation, UVA1 phototherapy and PUVA photochemotherapy in a variety of different connective tissue disorders. RESULTS: Potential pathways include immunomodulation of inflammation, induction of collagenases and initiation of apoptosis. Even though holding the risk of carcinogenesis, photoaging or UV-induced exacerbation, UVA phototherapy seems to exhibit a tolerable risk/benefit ratio at least in systemic sclerosis, localized scleroderma, extragenital lichen sclerosus et atrophicus, sclerodermoid graft-versus-host disease, lupus erythematosus and a number of sclerotic rarities. CONCLUSIONS: Based on the data retrieved from the literature, therapeutic UVA exposure seems to be effective in connective tissue diseases and related disorders. However, more controlled investigations are needed in order to establish a clear-cut catalogue of indications
Increased numbers of small circulating endothelial cells in renal cell cancer patients treated with sunitinib
Mature circulating endothelial cell (CEC) as well as endothelial progenitor populations may reflect the activity of anti-angiogenic agents on tumor neovasculature or even constitute a target for anti-angiogenic therapy. We investigated the behavior of CECs in parallel with hematopoietic progenitor cells (HPCs) in the blood of renal cell cancer patients during sunitinib treatment. We analyzed the kinetics of a specific population of small VEGFR2-expressing CECs (CD45(neg)/CD34(bright)), HPCs (CD45(dim)/CD34(bright)), and monocytes in the blood of 24 renal cell cancer (RCC) patients receiving 50 mg/day of the multitargeted VEGF inhibitor sunitinib, on a 4-week-on/2-week-off schedule. Blood was taken before treatment (C1D1), on C1D14, C1D28, and on C2D1 before the start of cycle 2. Also plasma VEGF and erythropoietin (EPO) were determined. Remarkably, while CD34(bright) HPCs and monocytes decreased during treatment, CD34(bright) CECs increased from 69 cells/ml (C1D1) to 180 cells/ml (C1D14; P = 0.001) and remained high on C1D28. All cell populations recovered to near pre-treatment levels on C2D1. Plasma VEGF and EPO levels were increased on C1D14 and partly normalized to pre-treatment levels on C2D1. In conclusion, opposite kinetics of two circulating CD34(bright) cell populations, HPCs and small CECs, were observed in sunitinib-treated RCC patients. The increase in CECs is likely caused by sunitinib targeting of immature tumor vessel
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