93 research outputs found
Mineral composition of organic and conventional white wines from Italy
Despite of the increased interest of consumers for organic agro-food products and of the growing demand for organic wines, scientific literature reports a limited number of studies aimed to evaluate the chemical composition of organic wine with respect to conventional wine in terms of major and trace metals. In the present study the concentrations of 19 elements (Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were determined in samples of white wines from Italy, conventionally and organically produced. No significant difference in the mineral composition was found between the two groups, except for Ni, which showed a higher concentration in organic wines. By comparing our data with data from literature it can be pointed out that there is no agreement among the results presented in the different studies referring to comparisons between organically and conventionally produced wines, concluding that the mineral composition of wines depends on factors different from organic/conventional production method
Critical parametric quantum sensing
Critical quantum systems are a promising resource for quantum metrology
applications, due to the diverging susceptibility developed in proximity of
phase transitions. Here, we assess the metrological power of parametric Kerr
resonators undergoing driven-dissipative phase transitions. We fully
characterize the quantum Fisher information for frequency estimation, and the
Helstrom bound for frequency discrimination. By going beyond the asymptotic
regime, we show that the Heisenberg precision can be achieved with
experimentally reachable parameters. We design protocols that exploit the
critical behavior of nonlinear resonators to enhance the precision of quantum
magnetometers and the fidelity of superconducting qubit readout.Comment: 6 pages + Supplemental Material, 4 figure
Pets as Sentinels of Human Exposure to Neurotoxic Metals
The idea that animals may be used as sentinels of environmental hazards
pending over humans and the associated public health implications is not a new one.
Nowadays pets are being used as bioindicators for the effects of environmental contaminants
in human populations. This is of paramount importance due to the large
increase in the worldwide distribution of synthetic chemicals, particularly in the
built environment. Companion animals share the habitat with humans being simultaneously
exposed to and suffering the same disease spectrum as their masters.
Moreover, their shorter latency periods (due to briefer lifespans) enable them to act
as early warning systems, allowing timely public health interventions. The rise on
ethical constraints on the use of animals and, consequently, on the sampling they
can be subjected to has led to the preferential use of noninvasive matrices, and in
this case we are looking into hair. This chapter focuses in three non-essential metals:
mercury, lead, and cadmium, due to their ubiquitous presence in the built environment
and their ability of affecting the mammal nervous system. There is a fairly
short amount of studies reporting the concentrations of these metals in pets’ hair,
particularly for cats. These studies are characterized, and the metal concentrations
corresponding to different parameters (e.g., age, sex, diet, rearing) are described in
order to provide the reader with a general vision on the use of this noninvasive
matrix on the studies conducted since the last two decades of the twentieth
century.publishe
Phenylthiourea Specifically Reduces Zebrafish Eye Size
Phenylthiourea (PTU) is commonly used for inhibiting melanization of zebrafish embryos. In this study, the standard treatment with 0.2 mM PTU was demonstrated to specifically reduce eye size in larval fish starting at three days post-fertilization. This effect is likely the result of a reduction in retinal and lens size of PTU-treated eyes and is not related to melanization inhibition. This is because the eye size of tyr, a genetic mutant of tyrosinase whose activity is inhibited in PTU treatment, was not reduced. As PTU contains a thiocarbamide group which is presented in many goitrogens, suppressing thyroid hormone production is a possible mechanism by which PTU treatment may reduce eye size. Despite the fact that thyroxine level was found to be reduced in PTU-treated larvae, thyroid hormone supplements did not rescue the eye size reduction. Instead, treating embryos with six goitrogens, including inhibitors of thyroid peroxidase (TPO) and sodium-iodide symporter (NIS), suggested an alternative possibility. Specifically, three TPO inhibitors, including those that do not possess thiocarbamide, specifically reduced eye size; whereas none of the NIS inhibitors could elicit this effect. These observations indicate that TPO inhibition rather than a general suppression of thyroid hormone synthesis is likely the underlying cause of PTU-induced eye size reduction. Furthermore, the tissue-specific effect of PTU treatment might be mediated by an eye-specific TPO expression. Compared with treatment with other tyrosinase inhibitors or bleaching to remove melanization, PTU treatment remains the most effective approach. Thus, one should use caution when interpreting results that are obtained from PTU-treated embryos
Tree bark as a bioindicator of the presence of scandium, yttrium and lanthanum in urban environments
Although rare earth elements (REEs) are important in modern industry, few processes use them, so the
possibility of these elements being dispersed in the environment is small. For this reason, there are few
studies on their presence in urban environments. REEs exhibit similar chemical properties, and Group 3
elements may be used as indicators of the presence of other REEs in the environment. Tree bark is a
suitable collector of airborne trace elements and has been successfully used as a bioindicator. In this
study, samples of holm oak bark were collected from three sampling sites subjected to different anthropic
pressures (one area is far from human influence, while the other two sites are urban areas
characterized by different types of human impact). The reference area is significantly different from
urban areas where the concentrations measured are up to 5 times higher (Y) than the reference area. The
differences between the two urban areas are also significant. The presence of industrial activities causes a
50% higher exposition of the population with respect to an urban area where only residential activities
are present. In the case of La, there is no significant difference between the reference and the residential
areas, while the industries are responsible for higher La concentrations (0.9 mg g-1 vs. 0.4-0.6 mg g-1).
The availability of samples, due to the wide distribution of trees in urban environments, makes possible
the production of maps indicating the sources of these elements and highlighting areas which are critical
for certain atmospheric pollutants
The concentrations of Pb, Cd, Cu, Zn, and V in Adamussium colbecki from Terra Nova Bay (Antarctica).
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