120 research outputs found
Relation between dietary cadmium intake and biomarkers of cadmium exposure in premenopausal women accounting for body iron stores
<p>Abstract</p> <p>Background</p> <p>Cadmium is a widespread environmental pollutant with adverse effects on kidneys and bone, but with insufficiently elucidated public health consequences such as risk of end-stage renal diseases, fractures and cancer. Urinary cadmium is considered a valid biomarker of lifetime kidney accumulation from overall cadmium exposure and thus used in the assessment of cadmium-induced health effects. We aimed to assess the relationship between dietary cadmium intake assessed by analyses of duplicate food portions and cadmium concentrations in urine and blood, taking the toxicokinetics of cadmium into consideration.</p> <p>Methods</p> <p>In a sample of 57 non-smoking Swedish women aged 20-50 years, we assessed Pearson's correlation coefficients between: 1) Dietary intake of cadmium assessed by analyses of cadmium in duplicate food portions collected during four consecutive days and cadmium concentrations in urine, 2) Partial correlations between the duplicate food portions and urinary and blood cadmium concentrations, respectively, and 3) Model-predicted urinary cadmium concentration predicted from the dietary intake using a one-compartment toxicokinetic model (with individual data on age, weight and gastrointestinal cadmium absorption) and urinary cadmium concentration.</p> <p>Results</p> <p>The mean concentration of cadmium in urine was 0.18 (+/- s.d.0.12) μg/g creatinine and the model-predicted urinary cadmium concentration was 0.19 (+/- s.d.0.15) μg/g creatinine. The partial Pearson correlations between analyzed dietary cadmium intake and urinary cadmium or blood concentrations were r = 0.43 and 0.42, respectively. The correlation between diet and urinary cadmium increased to r = 0.54 when using a one-compartment model with individual gastrointestinal cadmium absorption coefficients based on the women's iron status.</p> <p>Conclusions</p> <p>Our results indicate that measured dietary cadmium intake can reasonably well predict biomarkers of both long-term kidney accumulation (urine) and short-term exposure (blood). The predictions are improved when taking data on the iron status into account.</p
Ground-state band and deformation of the Z=102 isotope 254No
The ground-state band of the Z=102 isotope 254No has been identified up to spin 14, indicating that the nucleus is deformed. The deduced quadrupole deformation, β=0.27, is in agreement with theoretical predictions. These observations confirm that the shell-correction energy responsible for the stability of transfermium nuclei is partly derived from deformation. The survival of 254No up to spin 14 means that its fission barrier persists at least up to that spin
Orientation dependence in molecular dynamics simulations of shocked single crystals
The entry distribution in angular momentum and excitation energy for the formation of 254No has been measured after the 208Pb reaction at 215 and 219 MeV. This nucleus is populated up to spin 22h and excitation energy >˜6 MeV above the yrast line, with the half-maximum points of the energy distributions at ˜5 MeV for spins between 12h and 22h. This suggests that the fission barrier is >˜5 MeV and that the shell-correction energy persists to high spin
Particle methods for maximum likelihood estimation in latent variable models
Standard methods for maximum likelihood parameter estimation
in latent variable models rely on the Expectation-Maximization algorithm and
its Monte Carlo variants. Our approach is different and motivated by similar
considerations to simulated annealing; that is we build a sequence of artificial
distributions whose support concentrates itself on the set of maximum likelihood estimates. We sample from these distributions using a sequential Monte
Carlo approach. We demonstrate state of the art performance for several applications of the proposed approach
High-spin states following multi-nucleon transfer
High-spin states in neutron-rich nuclei, populated
following deep-inelastic multi-nucleon transfer, have been
studied using the GAMMASPHERE array at the LBNL,
USA. A Ni beam at an energy above
the Coulomb barrier
was incident upon a thick Pb target, leading to the population of
more than 130 different nuclei. The strongest channels correspond to
nuclei close to the projectile and target, although transfer of up to
50 nucleons has been observed. New high-spin states in neutron-rich Fe
and Zn nuclei have been observed. Some
limitations of this method of high-spin spectroscopy are discussed,
including the apparent difficulty of populating odd-odd and odd-even
isotopes via this type of reaction.
The data have been searched for superdeformed (SD) states in the 190–200
region, but no evidence for their presence has been found
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