202 research outputs found
Trace elements in home-processed food obtained from unconventional animals
Wild animals have been used as food since ancient times and, currently, the consumption of unconventional animals is increasing worldwide. The process of cooking meat using traditional recipes includes a variety of ingredients, which can influence the total metal intake from the diet. In this study, the concentrations of eight essential (Fe, Zn, Cu, Mn, Se, Ni, Mo, and Co) and six non-essential (Pb, Cd, Hg, Al, As, and Cr) trace elements were determined in home-processed food obtained from snails and from three common species of game animals (woodcock, pheasant, and hare), seasoned with anchovies, mushrooms, and different vegetables using inductively coupled plasma mass spectrometry (ICP-MS). In general, Fe was the most abundant trace element, ranging from 18 \ub1 8 \u3bcg/g in pheasant to 99 \ub1 76 \u3bcg/g in snail, and Co was the least abundant, ranging from 0.007 \ub1 0.003 \u3bcg/g in hare to 0.093 \ub1 0.048 \u3bcg/g in snail. Regarding the non-essential trace elements, Pb concentrations showed wide variations, reaching a concentration of 17.30 \u3bcg/g in hare, while Cd concentrations were higher in snail, ranging from 0.18 to 0.46 \u3bcg/g. These alternative food sources can offer an important contribution to the human nutritional requirements of essential trace elements, in particular of Fe. The high concentrations of Pb and Cd present in some samples should be considered as potentially dangerous for the consumers
Coherent ultrafast spin-dynamics probed in three dimensional topological insulators
Topological insulators are candidates to open up a novel route in spin based
electronics. Different to traditional ferromagnetic materials, where the
carrier spin-polarization and magnetization are based on the exchange
interaction, the spin properties in topological insulators are based on the
coupling of spin- and orbit interaction connected to its momentum. Specific
ways to control the spin-polarization with light have been demonstrated: the
energy momentum landscape of the Dirac cone provides spin-momentum locking of
the charge current and its spin. The directionality of spin and momentum, as
well as control with light has been demonstrated. Here we demonstrate a
coherent femtosecond control of spin-polarization for states in the valence
band at around the Dirac cone.Comment: 14 pages, 4 figure
Ultrafast carrier dynamics in tetrahedral amorphous carbon: carrier trapping versus electron–hole recombination
We report the investigation of the ultrafast carrier dynamics in thin tetrahedral amorphous carbon films by means of femtosecond time-resolved reflectivity. We estimated the electronphonon relaxation time of a few hundred femtoseconds and we observed that under low optical excitation photo-generated carriers decay according to two distinct mechanisms attributed to trapping by defect states and direct electronhole recombination. With high excitation, when photo-carrier and trap densities are comparable, a unique temporal evolution develops, as the time dependence of the trapping process becomes degenerate with the electronhole recombination. This experimental evidence highlights the role of defects in the ultrafast electronic dynamics and is not specific to this particular form of carbon, but has general validity for amorphous and disordered semiconductors. peerReviewe
Coherent phonons and the interplay between charge density wave and Mott phases in 1-TaSe
1-TaSe is host to coexisting strongly-correlated phases including
charge density waves (CDWs) and an unusual Mott transition at low temperature.
Here, we investigate coherent phonon oscillations in 1-TaSe using a
combination of time- and angle-resolved photoemission spectroscopy (TR-ARPES)
and time-resolved reflectivity (TRR). Perturbation by a femtosecond laser pulse
triggers a modulation of the valence band binding energy at the -point,
related to the Mott gap, that is consistent with the in-plane CDW amplitude
mode frequency. By contrast, TRR measurements show a modulation of the
differential reflectivity comprised of multiple frequencies belonging to the
distorted CDW lattice modes. Comparison of the temperature dependence of
coherent and spontaneous phonons across the CDW transition shows that the
amplitude mode intensity is more easily suppressed during perturbation of the
CDW state by the optical excitation compared to other modes. Our results
clearly identify the relationship of the in-plane CDW amplitude mode with the
Mott phase in 1-TaSe and highlight the importance of lattice degrees
of freedom.Comment: 7 pages, 4 figures, supplemental materia
Magnetic anisotropy at the buried CoO/Fe interface
Interfaces between antiferromagnetic CoO and ferromagnetic Fe are typically characterized by the development of Fe oxides. Recently, it was shown that the use of a proper ultra-thin Co buffer layer prevents the formation of Fe oxides [Brambilla et al., Appl. Surf. Sci. 362, 374 (2016)]. In the present work, we investigate the magnetic properties of such an interface, and we find evidence for an in-plane uniaxial magnetic anisotropy, which is characterized by a multijump reversal behavior in the magnetization hysteresis loops. X-ray photoemission spectroscopy and element-sensitive hysteresis loops reveal that the occurrence of such an anisotropy is a phenomenon developing at the very interface
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