50 research outputs found
Surface modified Eu:GdVO4 nanocrystals for optical and MRI imaging
A facile solvothermal route has been developed for the preparation of europium doped gadolinium orthovanadate nanoparticles (âŒ70 nm) with tetragonal structure, based on a homogenous precipitation reaction at 120 °C from rare earth precursors (yttrium nitrate and europium nitrate) and sodium orthovanadate solutions using an ethylene glycol-water mixture as the solvent. The effects of the doping level on the luminescence properties were evaluated in order to find the optimum nanophosphors. These nanocrystals were successfully functionalized with amino (two step process) and carboxylate (one-pot process) groups provided by amino-dextran polymers (AMD) and polyacrylic acid (PAA), respectively. It was found that while the luminescent properties of both kinds of functionalized systems were similar, the colloidal stability of the PAA-modified sample was higher, because of which, it was selected to study their cytotoxicity and magnetic properties (relaxivity and phantom analyses) to assess their potentiality as multifunctional probes for both >in vitro> optical biolabels and negative contrast agents for magnetic resonance imaging. This journal is © The Royal Society of Chemistry 2013.Peer Reviewe
Chirality in odd- nucleus Nd in particle rotor model
A particle rotor model is developed which couples several valence protons and
neutrons to a rigid triaxial rotor core. It is applied to investigating the
chirality in odd- nucleus Nd with configuration for the first time in a fully quantal approach.
For the two chiral sister bands, the observed energies and the and
values for the in-band as well as interband transitions are reproduced
excellently. Root mean square values of the angular momentum components and
their probability distributions are used for discussing in detail the chiral
geometry of the aplanar rotation and its evolution with angular momentum.
Chirality is found to change from a soft chiral vibration to nearly static
chirality at spin and back to another type of chiral vibration at
higher spin.Comment: 16 pages, 5 figure
Elastic scattering, inelastic excitation, and neutron transfer for Li 7 + Sn 120 at energies around the Coulomb barrier
Experimental angular distributions for the
7
Li
+
120
Sn elastic and inelastic (projectile and target excitations)
scattering, and for the neutron stripping reaction, have been obtained at
E
LAB
=
20, 22, 24, and 26 MeV, covering
an energy range around the Coulomb barrier (
V
(LAB)
B
â
21
.
4 MeV). Coupled channel and coupled reaction channel
calculations were performed and both describe satisfactorily the experimental data sets. The
1
2
â
state
7
Li inelastic
excitation (using a rotational model), as well as the projectile coupling to the continuum (
α
plus a tritium particle)
play a fundamental role on the proper description of elastic, inelastic, and transfer channels. Couplings to the
one-neutron stripping channel do not significantly affect the theoretical elastic scattering angular distributions.
The spectroscopic amplitudes of the transfer channel were obtained through a shell model calculation. The
theoretical angular distributions for the one-neutron stripping reaction agreed with the experimental data
Spectroscopy of Na: Bridging the two-proton radioactivity of Mg
The unbound nucleus Na, the intermediate nucleus in the two-proton
radioactivity of Mg, was studied by the measurement of the resonant
elastic scattering reaction Ne(p,Ne)p performed at 4 A.MeV.
Spectroscopic properties of the low-lying states were obtained in a R-matrix
analysis of the excitation function. Using these new results, we show that the
lifetime of the Mg radioactivity can be understood assuming a sequential
emission of two protons via low energy tails of Na resonances
Nuclear charge radius of He
The root-mean-square (rms) nuclear charge radius of ^8He, the most
neutron-rich of all particle-stable nuclei, has been determined for the first
time to be 1.93(3) fm. In addition, the rms charge radius of ^6He was measured
to be 2.068(11) fm, in excellent agreement with a previous result. The
significant reduction in charge radius from ^6He to ^8He is an indication of
the change in the correlations of the excess neutrons and is consistent with
the ^8He neutron halo structure. The experiment was based on laser spectroscopy
of individual helium atoms cooled and confined in a magneto-optical trap.
Charge radii were extracted from the measured isotope shifts with the help of
precision atomic theory calculations
Search for lepton-number violating B+ -> X(-)l(+)l '(+) decays
We report on a search for eleven lepton-number violating processes B+ -> X(-)l(+)l'(+) with X- = K-, pi(-), rho(-), K*(-), or D- and l(+)/l'(+) = e(+) or mu(+), using a sample of 471 +/- 3 million B (B) over bar events collected with the BABAR detector at the PEP-II e(+)e(-) collider at the SLAC National Accelerator Laboratory. We find no evidence for any of these modes and place 90% confidence level upper limits on their branching fractions in the range (1.5-26) x 10(-7)
The management of acute venous thromboembolism in clinical practice. Results from the European PREFER in VTE Registry
Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in Europe. Data from real-world registries are necessary, as clinical trials do not represent the full spectrum of VTE patients seen in clinical practice. We aimed to document the epidemiology, management and outcomes of VTE using data from a large, observational database. PREFER in VTE was an international, non-interventional disease registry conducted between January 2013 and July 2015 in primary and secondary care across seven European countries. Consecutive patients with acute VTE were documented and followed up over 12 months. PREFER in VTE included 3,455 patients with a mean age of 60.8 ± 17.0 years. Overall, 53.0 % were male. The majority of patients were assessed in the hospital setting as inpatients or outpatients (78.5 %). The diagnosis was deep-vein thrombosis (DVT) in 59.5 % and pulmonary embolism (PE) in 40.5 %. The most common comorbidities were the various types of cardiovascular disease (excluding hypertension; 45.5 %), hypertension (42.3 %) and dyslipidaemia (21.1 %). Following the index VTE, a large proportion of patients received initial therapy with heparin (73.2 %), almost half received a vitamin K antagonist (48.7 %) and nearly a quarter received a DOAC (24.5 %). Almost a quarter of all presentations were for recurrent VTE, with >80 % of previous episodes having occurred more than 12 months prior to baseline. In conclusion, PREFER in VTE has provided contemporary insights into VTE patients and their real-world management, including their baseline characteristics, risk factors, disease history, symptoms and signs, initial therapy and outcomes
Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137
Spallation reactions for the long-lived fission products 137Cs, 90Sr and 107Pd have been studied for the purpose of nuclear waste transmutation. The cross sections on the proton- and deuteron-induced spallation were obtained in inverse kinematics at the RIKEN Radioactive Isotope Beam Factory. Both the target and energy dependences of cross sections have been investigated systematically. and the cross-section differences between the proton and deuteron are found to be larger for lighter fragments. The experimental data are compared with the SPACS semi-empirical parameterization and the PHITS calculations including both the intra-nuclear cascade and evaporation processes
New Isomers in the Full Seniority Scheme of Neutron-Rich Lead Isotopes: The Role of Effective Three-Body Forces
The neutron-rich lead isotopes, up to Pb-216, have been studied for the first time, exploiting the fragmentation of a primary uranium beam at the FRS-RISING setup at GSI. The observed isomeric states exhibit electromagnetic transition strengths which deviate from state-of-the-art shell-model calculations. It is shown that their complete description demands the introduction of effective three-body interactions and two-body transition operators in the conventional neutron valence space beyond Pb-208.INFN, ItalyINFN, ItalyMICINN, Spain [AIC10-D-000568]MICINN, SpainGeneralitat Valenciana, SpainGeneralitat Valenciana, Spain [FPA2008-06419, PROMETEO/2010/101]UK STFCUK STFCAWE plcAWE plcDFGDFG [EXC 153