Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ital J Food Saf ; 10(3): 9576, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34703791

RESUMO

Sea cucumbers represent an important part of the diet in Asian and Pacific regions and are also used in traditional medicine. These habits have led to the overexploitation of local sea cucumber populations in these areas, driving the pursuit of new stock regions, such as Mediterranean areas. In Italy, contrarily to that observed for other Mediterranean countries, the exploitation of sea cucumber stocks is not extensive, which opens a new market opportunity. Thus, from a food safety perspective, this work aims at reporting the first assessment of trace metal concentrations (As, Cd, Cr, Cu, Hg, Ni, Pb) in the edible tissues of Holothuria polii and Holoturia tubulosa collected in Sardinia, the second-largest island in the Mediterranean Sea. Metal concentrations found in H. polii were generally higher than in H. tubulosa. However, in both species, they were lower than those reported for other areas of the Western Mediterranean. Cd, Hg, and Pb were below the limits established for seafood in Europe. As concentrations were in the range of those measured in other commercial seafood species in the Mediterranean. Thus, these species may be harvested and traded to fulfil the demands of local and international markets.

2.
Mar Pollut Bull ; 150: 110692, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31744611

RESUMO

Diffusive gradients in thin films (DGTs) were used for monitoring metal (Cd, Cu, Ni, and Pb) concentrations in protected and non-protected coastal areas in Sardinia (Western Mediterranean). The deployment of DGTs in relatively undisturbed areas enabled calculation of operational DGT threshold values, which can be used for assessments of the environmental quality of coastal areas. The DGT thresholds were defined as the median metal concentrations that were found in protected areas, which ensured consideration of the natural variability of the different study sites. The calculated DGT thresholds were 11.6 ng L-1 for Pb, 5.1 ng L-1 for Cd, 63 ng L-1 for Cu and 152 ng L-1 for Ni. A comparison of the calculated DGT thresholds with previous DGT studies in the area demonstrated their suitability for identifying sites of environmental concern in the Western Mediterranean.


Assuntos
Monitoramento Ambiental , Metais/análise , Poluentes Químicos da Água/análise , Itália , Água do Mar/química
3.
Chem Commun (Camb) ; 53(87): 11869-11872, 2017 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-29038809

RESUMO

The first example of a molecular logic gate based on selenourea/anion host-guest interaction that performs a ternary logic operation using an 1H-NMR easy to read response output is described here. Selenoureas are very versatile receptors for anion binding, capable of forming both mono- and bi-coordinated adducts at room temperature in solution.


Assuntos
Ânions/química , Compostos Organosselênicos/química , Ureia/análogos & derivados , Sítios de Ligação , Computadores Moleculares , Espectroscopia de Prótons por Ressonância Magnética , Ureia/química
4.
J Colloid Interface Sci ; 477: 8-15, 2016 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-27236839

RESUMO

The recognition of nucleotides is of crucial importance because they are the basic constituents of nucleic acids. The present study is focused on the selective interaction between a novel amphiphilic fluorophore containing coumarin and imidazole, CI (1-methyl-3-(12-((2-oxo-2H-chromen-7-yl)oxy)dodecyl)-1H-imidazol-3-ium bromide), and different nucleotide-monophosphates (NMPs). It was supposed that the solubilization of the low water soluble CI in a micelle system of hexadecyltrimethylammonium chloride (CTAC) would make the coumarin moiety of CI available to the interaction with the water-soluble NMPs. Changes in CTAC critical micelle concentration suggested that CI strongly interacted with the host cationic surfactant, thus forming a positively charged interface enriched with coumarin able to interact with the anionic NMPs. Steady-state fluorescence quenching revealed that CI/CTAC system was capable of distinguish between purine- and pyrimidine-based nucleotides. A modified Stern-Volmer equation permitted the use of a quenching model that accounted for the possible interactions between the micelles and the nucleotides. The data analysis allowed calculating selective parameters that differentiated according to the type of nucleotide either at 25 or 50°C. Our results established the utility of the novel coumarin derivative fluorophore, supported by the simple and suitable micellar systems, as a tool for DNA sensing applications.


Assuntos
Cumarínicos/química , Micelas , Nucleotídeos/análise , Compostos de Amônio Quaternário/química , Fluorescência , Estrutura Molecular
5.
Dalton Trans ; 45(7): 3078-85, 2016 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-26765955

RESUMO

Three fluorescent asymmetric bis-urea receptors (L1-L3) have been synthesised. The binding properties of L1-L3 towards different anions (fluoride, acetate, hydrogencarbonate, dihydrogen phosphate, and hydrogen pyrophosphate HPpi(3-)) have been studied by means of (1)H-NMR, UV-Vis and fluorescence spectroscopy, single crystal X-ray diffraction, and theoretical calculations. In particular, a remarkable affinity for HPpi(3-) has been observed in the case L1 (DMSO-d6/0.5% H2O) which also acts as a fluorimetric chemosensor for this anion. Interestingly, when L1 is included in cetyltrimethylammonium (CTAB) micelles, hydrogen pyrophosphate recognition can also be achieved in pure water.


Assuntos
Difosfatos/análise , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Ureia/química , Água/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Espectrometria de Fluorescência , Difração de Raios X
6.
Dalton Trans ; 44(21): 9805-14, 2015 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-25928254

RESUMO

The tetrahedral S-coordinated complex [Zn(MeImHS)4](ClO4)2, synthesised from the reaction of [Zn(ClO4)2] with methimazole (1-methyl-3H-imidazole-2-thione, MeImHS), reacts with triethylamine to yield the homoleptic complex [Zn(MeImS)2] (MeImS = anion methimazole). ESI-MS and MAS (13)C-NMR experiments supported MeImS acting as a (N,S)-chelating ligand. The DFT-optimised structure of [Zn(MeImS)2] is also reported and the main bond lengths compared to those of related Zn-methimazole complexes. The complex [Zn(MeImS)2] reacts under mild conditions with methyl iodide and separates the novel complex [Zn(MeImSMe)2I2] (MeImSMe = S-methylmethimazole). X-ray diffraction analysis of the complex shows a ZnI2N2 core, with the methyl thioethers uncoordinated to zinc. Conversely, the reaction of [Zn(MeImS)2] with hydroiodic acid led to the formation of the complex [Zn(MeImHS)2I2] having a ZnI2S2 core with the neutral methimazole units S-coordinating the metal centre. The Zn-coordinated methimazole can markedly modify the coordination environment when changing from its thione to thionate form and vice versa. The study of the interaction of the drug methimazole with the complex [Zn(MeIm)4](2+) (MeIm = 1-methylimidazole) - as a model for Zn-enzymes containing a N4 donor set from histidine residues - shows that methimazole displaces only one of the coordinated MeIm molecules; the formation constant of the mixed complex [Zn(MeIm)3(MeImHS)](2+) was determined.


Assuntos
Complexos de Coordenação/química , Imidazóis/química , Zinco/química , Cristalografia por Raios X , Espectrometria de Massas , Espectrofotometria Ultravioleta
7.
Chem Soc Rev ; 44(14): 4645-71, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-25406516

RESUMO

This review describes the recent advances in the development of imaging agents based on silica nanoparticles. Different techniques (magnetic resonance imaging, optical imaging, positron emission tomography, X-ray computed tomography, and ultrasound imaging) are described as well as the possibility of combining together different imaging techniques in the same nanoplatform and simultaneously performing imaging and therapy.


Assuntos
Meios de Contraste , Nanopartículas , Dióxido de Silício , Animais , Linhagem Celular Tumoral , Imageamento por Ressonância Magnética , Camundongos , Coelhos , Tomografia Computadorizada por Raios X
8.
Chemistry ; 13(19): 5401-7, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17361971

RESUMO

We report the anion-templated syntheses of a variety of supramolecular assemblies of Co(II). Remarkably in the presence of a weakly coordinating ion such as BF(4) (-), a discrete three-dimensional cage [BF(4) subset(BF(4))(2)Co(2)(L(1))(4)][BF(4)] (2) is formed with three coordinated BF(4) (-) ions, a rare example in supramolecular chemistry (L(1)=di(benzimidazole)-1,4-phenylene). Switching to stronger coordinating ions, such as NO(3) (-) or Cl(-), a one-dimensional coordination polymer [[Co(L(1))(NO(3))(2)](n)] (3) and a metallomacrocycle [Co(2)(L(1))(2)(Cl)(4)] (5) were formed, respectively. These results illustrate the powerful effect of the anion-templating chemistry. Finally the magnetic properties of these assemblies 1 b, 2, 3, and 5 are presented and discussed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...