281 research outputs found
Experimental study of fragmentation products in the reactions 112Sn + 112Sn and 124Sn + 124Sn at 1 AGeV
Production cross-sections and longitudinal velocity distributions of the
projectile-like residues produced in the reactions 112Sn + 112Sn and 124Sn +
124Sn both at an incident beam energy of 1 AGeV were measured with the
high-resolution magnetic spectrometer, the Fragment Separator (FRS) of GSI. For
both reactions the characteristics of the velocity distributions and nuclide
production cross sections were determined for residues with atomic number Z
10. A comparison of the results of the two reactions is presented.Comment: 14 pages, 12 figure
Potential of Salvinia biloba Raddi for removing atrazine and carbendazim from aquatic environments
Abstract:
In this exploratory study, naturally occurring Salvinia biloba Raddi specimens were assessed for atrazine and carbendazim
polluted water remediation. Experiments were carried out over 21 days in glass vessels containing deionized water artifcially
contaminated with 0, 5, 10, and 20 mg Lâ1 of atrazine or carbendazim. Atrazine had a pronounced detrimental impact on
S. biloba, as no biomass development was observed in all macrophytes exposed to this herbicide in the entire concentration
range. However, carbendazim-treated plants were able to grow and survive in the polluted medium even when subjected to
the highest concentration of this fungicide (i.e., 20 mg Lâ1). In addition, increased chlorosis and necrosis were also detected
in plants subjected to carbendazim as a result of the high phytotoxicity caused by atrazine. A maximal removal efciency
of~30% was observed for both pesticides at 5 mg Lâ1 and decreased with increasing concentrations of the pollutants. The
spectrum of the FTIR-ATR analysis revealed the existence of various functional groups (e.g., amide, carboxyl, hydroxyl,
phosphate, sulfate) on the plants, which could be related to pesticide biosorption. In addition, at the end of the 21-day
assay, seven carbendazim-resistant bacteria could be isolated from the roots of fungicide-treated plants. Therefore, the use
of autochthonous free-foating S. biloba macrophytes for phytoremediation of aquatic environments contaminated with
carbendazim shows great promise. Still, additional research is required to further elucidate the plant-mediated carbendazim
elimination process and the role of the herbicide-resistant bacteria, and seek alternative species capable of mitigating atrazine
contamination
Shape effect in active targeting of nanoparticles to inflamed cerebral endothelium under static and flow conditions
Endothelial cells represent the first biological barrier for compounds, including nanoparticles, administered via the intravascular route. In the case of ischemic stroke and other vascular diseases, the endothelium overexpresses specific markers, which can be used as molecular targets to facilitate drug delivery and imaging. However, targeting these markers can be quite challenging due to the presence of blood flow and the associated hydrodynamic forces, reducing the likelihood of adhesion to the vessel wall. To overcome these challenges, various parameters including size, shape, charge or ligand coating have been explored to increase the targeting efficiency. Geometric shape can modulate nanoparticle binding to the cell, especially by counteracting part of the hydrodynamic forces of the bloodstream encountered by the classical spherical shape. In this study, the binding affinity of polystyrene nanoparticles with two different shapes, spherical and rod-shaped, were compared. First, vascular adhesion molecule-1 (VCAM-1) was evaluated as a vascular target of inflammation, induced by lipopolysaccharide (LPS) stimulation. To evaluate the effect of nanoparticle shape on particle adhesion, nanoparticles were coated with anti-VCAM-1 and tested under static conditions in cell culture dishes coated with cerebral microvasculature cells (bEnd.3) and under dynamic flow conditions in microfluidic channels lined with hCMEC/D3 cells. Effect of particle shape on accumulation was also assessed in two in vivo models including systemic inflammation and local brain inflammation. The elongated rod-shaped particles demonstrated greater binding ability in vitro, reaching a 2.5-fold increase in the accumulation for static cultures and 1.5-fold for flow conditions. Anti-VCAM-1 coated rods exhibited a 3.5-fold increase in the brain accumulation compared to control rods. These results suggest shape offers a useful parameter in future design of drug delivery nanosystems or contrast agents for neurovascular pathologies.This study has been partially supported by grants from Instituto de Salud Carlos III (PI13/00292 and PI17/0054), Spanish ResearchNetwork on Cerebrovascular Diseases RETICS-INVICTUS (RD12/0014),FundaciĂłn Mutua Madrileña. The Ministry of Economy and Competitiveness of Spain (SAF2017-84267-R). The European Union program FEDER and the European Regional Development FundâERDF, MADIA project No. 732678 to FC. Furthermore, F. Campos (CP14/00154) recipients a research contract from Miguel Servet Program of Instituto de Salud Carlos III. National Science Foundation Graduate Research Fellowship under Grant DGE-1745303S
Production of neutron-rich nuclei in fragmentation reactions of 132Sn projectiles at relativistic energies
The fragmentation of neutron-rich 132Sn nuclei produced in the fission of
238U projectiles at 950 MeV/u has been investigated at the FRagment Separator
(FRS) at GSI. This work represents the first investigation of fragmentation of
medium-mass radioactive projectiles with a large neutron excess. The measured
production cross sections of the residual nuclei are relevant for the possible
use of a two-stage reaction scheme (fission+fragmentation) for the production
of extremely neutron-rich medium-mass nuclei in future rare-ion-beam
facilities. Moreover, the new data will provide a better understanding of the
"memory" effect in fragmentation reactions.Comment: 5 pages, 3 figure
Experimental investigation of ground-state properties of <sup>7</sup>H with transfer reactions
The properties of nuclei with extreme neutronâtoâproton ratios, far from those naturally occurring on Earth, are key to understand nuclear forces and how nucleons hold together to form nuclei. 7H, with six neutrons and a single proton, is the nuclear system with the most unbalanced neutronâtoâproton ratio known so far. However, its sheer existence and properties are still a challenge for experimental efforts and theoretical models. Here we report experimental evidences on the formation of 7H as a resonance, detected with independent observables, and the first measurement of the structure of its ground state. The resonance is found at âŒ0.7 MeV above the 3H+4n mass, with a narrow width of âŒ0.2 MeV and a 1/2+ spin and parity. These data are consistent with a 7H as a 3H core surrounded by an extended four-neutron halo, with a unique four-neutron decay and a relatively long half-life thanks to neutron pairing; a prime example of new phenomena occurring in what would be the most pure-neutron nuclear matter we can access in the laboratory.</p
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