| 1. |
- Athan, E., et al.
(författare)
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Influence of vancomycin minimum inhibitory concentration on the outcome of methicillin-susceptible Staphylococcus aureus left-sided infective endocarditis treated with antistaphylococcal β-lactam antibiotics: a prospective cohort study by the International Collaboration on Endocarditis
- 2017
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 23, s. 544-549
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 European Society of Clinical Microbiology and Infectious Diseases Objectives Left-sided methicillin-susceptible Staphylococcus aureus (MSSA) endocarditis treated with cloxacillin has a poorer prognosis when the vancomycin minimum inhibitory concentration (MIC) is ≥1.5 mg/L. We aimed to validate this using the International Collaboration on Endocarditis cohort and to analyse whether specific genetic characteristics were associated with a high vancomycin MIC (≥1.5 mg/L) phenotype. Methods All patients with left-sided MSSA infective endocarditis treated with antistaphylococcal β-lactam antibiotics between 2000 and 2006 with available isolates were included. Vancomycin MIC was determined by Etest as either high (≥1.5 mg/L) or low (<1.5 mg/L). Isolates underwent spa typing to infer clonal complexes and multiplex PCR for identifying virulence genes. Univariate analysis was performed to evaluate the association between in-hospital and 1-year mortality, and vancomycin MIC phenotype. Results Sixty-two cases met the inclusion criteria. Vancomycin MIC was low in 28 cases (45%) and high in 34 cases (55%). No significant differences in patient demographic data or characteristics of infection were observed between patients with infective endocarditis due to high and low vancomycin MIC isolates. Isolates with high and low vancomycin MIC had similar distributions of virulence genes and clonal lineages. In-hospital and 1-year mortality did not differ significantly between the two groups (32% (9/28) vs. 27% (9/34), p 0.780; and 43% (12/28) vs. 29% (10/34), p 0.298, for low and high vancomycin MIC respectively). Conclusions In this international cohort of patients with left-sided MSSA endocarditis treated with antistaphylococcal β-lactams, vancomycin MIC phenotype was not associated with patient demographics, clinical outcome or virulence gene repertoire.
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| 2. |
- Bertucci, Antonella, et al.
(författare)
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Shielding of relativistic protons
- 2007
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 46:2, s. 107-111
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Tidskriftsartikel (refereegranskat)abstract
- Protons are the most abundant element in the galactic cosmic radiation, and the energy spectrum peaks around 1 GeV. Shielding of relativistic protons is therefore a key problem in the radiation protection strategy of crewmembers involved in long-term missions in deep space. Hydrogen ions were accelerated up to 1 GeV at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, New York. The proton beam was also shielded with thick ( about 20 g/cm(2)) blocks of lucite (PMMA) or aluminium ( Al). We found that the dose rate was increased 40-60% by the shielding and decreased as a function of the distance along the axis. Simulations using the General Purpose Particle and Heavy-Ion Transport code System (PHITS) show that the dose increase is mostly caused by secondary protons emitted by the target. The modified radiation Weld after the shield has been characterized for its biological eVectiveness by measuring chromosomal aberrations in human peripheral blood lymphocytes exposed just behind the shield block, or to the direct beam, in the dose range 0.53 Gy. Notwithstanding the increased dose per incident proton, the fraction of aberrant cells at the same dose in the sample position was not significantly modified by the shield. The PHITS code simulations show that, albeit secondary protons are slower than incident nuclei, the LET spectrum is still contained in the low-LET range (
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| 3. |
- Casolino, M., et al.
(författare)
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The altcriss project on board the International Space Station
- 2007
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Ingår i: Advances in Space Research. - : Elsevier BV. - 1879-1948 .- 0273-1177. ; 40:11, s. 1746-1753
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Tidskriftsartikel (refereegranskat)abstract
- The Alteriss project aims to perform a long term survey of the radiation environment on board the International Space Station. Measurements are being performed with active and passive devices in different locations and orientations of the Russian segment of the station. The goal is to perform a detailed evaluation of the differences in particle fluence and nuclear composition due to different shielding material and attitude of the station. The Sileye-3/Alteino detector is used to identify nuclei up to Iron in the energy range above similar or equal to 60 MeV/n. Several passive dosimeters (TLDs, CR39) are also placed in the same location of Sileye-3 detector. Polyethylene shielding is periodically interposed in front of the detectors to evaluate the effectiveness of shielding on the nuclear component of the cosmic radiation. The project was submitted to ESA in reply to the AO in the Life and Physical Science of 2004 and data taking began in December 2005. Dosimeters and data cards are rotated every 6 months: up to now three launches of dosimeters and data cards have been performed and have been returned with the end of expedition 12 and 13. (C) 2007 Published by Elsevier Ltd on behalf of COSPAR.
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| 4. |
- Henthorn, Nicholas T., et al.
(författare)
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Mapping the Future of Particle Radiobiology in Europe : The INSPIRE Project
- 2020
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Ingår i: Frontiers in Physics. - : Frontiers Media SA. - 2296-424X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Particle therapy is a growing cancer treatment modality worldwide. However, there still remains a number of unanswered questions considering differences in the biological response between particles and photons. These questions, and probing of biological mechanisms in general, necessitate experimental investigation. The "Infrastructure in Proton International Research" (INSPIRE) project was created to provide an infrastructure for European research, unify research efforts on the topic of proton and ion therapy across Europe, and to facilitate the sharing of information and resources. This work highlights the radiobiological capabilities of the INSPIRE partners, providing details of physics (available particle types and energies), biology (sample preparation and post-irradiation analysis), and researcher access (the process of applying for beam time). The collection of information reported here is designed to provide researchers both in Europe and worldwide with the tools required to select the optimal center for their research needs. We also highlight areas of redundancy in capabilities and suggest areas for future investment.
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| 5. |
- Mancusi, Davide, 1980, et al.
(författare)
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Comparison of aluminum and lucite for shielding against 1 GeV protons
- 2007
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Ingår i: Advances in Space Research. - : Elsevier BV. - 1879-1948 .- 0273-1177. ; 40:4, s. 581-585
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Tidskriftsartikel (refereegranskat)abstract
- Shielding is the only countermeasure currently available for exposure to cosmic radiation during space travel. We compared aluminum (Al) and polymethylmethacrylate (PMMA, or lucite) shields of 20 g/cm^2 thickness using 1 GeV protons accelerated at the NASA Space Radiation Laboratory. The dose rate increased after the shield, and the increase was more pronounced after the Al than the PMMA shield. No significant differences in the induction of chromosomal aberrations were observed in human lymphocytes exposed to the same dose with no shield or behind the Al and PMMA blocks. However, the biological effectiveness per incident proton was increased by the shields. Simulations using the General-Purpose Particle and Heavy-Ion Transport Code System (PHITS) show that the increase in dose is caused by target fragments, and aluminum produces more secondary protons than PMMA. Nevertheless, the spectrum of particles behind the shield is confined within the low-LET region, and the biological effectiveness is consequently similar.
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| 6. |
- Norbury, John W., et al.
(författare)
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Are Further Cross Section Measurements Necessary for Space Radiation Protection or Ion Therapy Applications? Helium Projectiles
- 2020
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Ingår i: Frontiers in Physics. - : Frontiers Media SA. - 2296-424X. ; 8
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Forskningsöversikt (refereegranskat)abstract
- The helium ((Formula presented.) He) component of the primary particles in the galactic cosmic ray spectrum makes significant contributions to the total astronaut radiation exposure. (Formula presented.) He ions are also desirable for direct applications in ion therapy. They contribute smaller projectile fragmentation than carbon ((Formula presented.) C) ions and smaller lateral beam spreading than protons. Space radiation protection and ion therapy applications need reliable nuclear reaction models and transport codes for energetic particles in matter. Neutrons and light ions ((Formula presented.) H, (Formula presented.) H, (Formula presented.) H, (Formula presented.) He, and (Formula presented.) He) are the most important secondary particles produced in space radiation and ion therapy nuclear reactions; these particles penetrate deeply and make large contributions to dose equivalent. Since neutrons and light ions may scatter at large angles, double differential cross sections are required by transport codes that propagate radiation fields through radiation shielding and human tissue. This work will review the importance of (Formula presented.) He projectiles to space radiation and ion therapy, and outline the present status of neutron and light ion production cross section measurements and modeling, with recommendations for future needs.
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