1,721,053 research outputs found
Metal chelates of 2-hydroxy-4-methylthiobutanoic acid in animal feeding: characterization, in vitro and in vivo investigations.
No full textMetal chelates of 2-hydroxy-4-methylthiobutanoic acid in animal feeding: characterization, in vitro and in vivo investigations
Giacomo Biagi,a Enrico Cinti,b Simonetta Ferruzza,c Attilio L. Mordenti,a Giovanni Predieri,d Matteo Tegonid
aDIMORFIPA, University of Bologna, Via Tolara di Sopra 50, Ozzano Emilia, Italy; bAgristudio S.r.l., Via Gramsci 56, Reggio Emilia, Italy; cINRAN, Nutrition National Institute, Via Ardeatina 546, Roma; aGIAF Chemistry Department, University of Parma, Parco delle Scienze, Parma, Italy
Interest in using alternative mineral sources, particularly those chelated with proteins or aminoacids, has recently increased due to their reported higher availability compared to conventional (inorganic) sources [1]. For example, it has been found that ruminants respond (increased growth, milk production etc.) to certain trace mineral complexes or chelates [2] and that aminoacid chelates show a higher availability than the inorganic compounds when fed to rainbow trouts, even in presence of phosphates and phytates [3]. However, there are still contentions both regarding improved bio-availability and integrity of metal chelates at the low pH of the first digestive tract. This important drawback can be overcome by using a chelating ligand able to improve the stability of chelates at low pH values. Preliminary results of our investigations [4] indicate that 2-hydroxy-4-methylthiobutanoic acid (MHA; the so-called methionine hydroxy-analogue), an alpha-hydroxyacid largely used in animal nutrition as a source of methionine has the requested features. It forms bis-chelate complexes of formula [{CH3SCH2CH2CH(OH)COO}2M].nH2O (M = Ca2+, Mg2+, Mn2+, Fe2+, Co2+, Cu2+ or Zn2+). Potentiometric investigations for the copper(II), zinc(II) and iron(III) MHA chelates in solution show that these species, differently from AA chelates, are rather stable even at low pH values. In the case of iron, the distribution diagram of the system Fe3+/MHA does not show any trace of free iron cations at pH > 2.5. Furthermore, in order to gain insight about biavailability of MHA chelates, in vitro and in vivo investigations were performed. In the in vitro studies, human intestinal Caco-2 cells were exposed to Fe3+/MHA chelate solutions. The iron/MHA chelate did not alter the permeability of Caco-2 tight junctions and was taken up to a larger extent than the reference iron chelated with nitrilotriacetic acid. In vivo investigations were carried out in the rat. After receiving a zinc-deficient diet for 3 weeks, animals were fed the same diet added with zinc sulfate or zinc/MHA chelate; the zinc content of faeces was higher (+ 45%; P < 0.05) in sulfate fed rats, whereas zinc retention was higher (+ 61%; P < 0.05) in the Zn/MHA diet.
References
[1] Ashmead, H.D., 1992, The Roles of AA Chelates in Animal Nutrition, Moyes Publ., Park Ridge, NJ. [2] Spears, J.W., 1996, Anim. Feed Sci. Technol., 58, 151-163. [3] Satoh, S. et al., 2003, Aquacult., 225, 431-444. [4] Predieri, G. et al., 2003, J. Inorg. Biochem., 95, 221-224
Nanostructured coating and innovative organic-inorganic consolidant: efficiency tests on a calcarenite from Sabucina (Sicily)
No full textNatural stones used in historical buildings often suffer the effects of weathering and degradation processes. In order to preserve and conserve natural building stones, in recent years suitablesynthesized products have been deeply investigated. In the frame of the synthesis of innovative, cheap, eco-friendly, reversible, compatible and high activity products, nanostructured materials represent a cutting edge technology. In particular, TiO2 nanoparticles are an efficient coating product in view ofits self-cleaning photocatalytic action, as testified by the successfully results on Sicilian calcarenite(Bergamonti et al., 2013). However, surface coating could not be a complete solution for conservation purposes, especially when the structural, textural and porosimetric features of the stones requirean integrated preservation and conservation effect both in terms of surface protection and of structural strengthening.Consolidant products are widely used in order to improve durability of building stones and the current researches are focused to test innovative products with high compatibility and low impact.
In this work we present the results obtained on the Sabucinastone, a calcarenite outcropping in Central Sicily and widely used as building and replacing stone, by applying coatings based on TiO2 nanoparticles and hybrid organic-inorganic consolidant products also associated with hydrophobic coating.
Referring to TiO2nanostructured coating, we tested self-cleaning photocatalytic coatings obtained by sol–gel processat different pH values. Photocatalytic activity of theTiO2 coatings onSabucinastone wasassessed under daylight and ultraviolet irradiation, monitoring methylorange (MeO) and methylene blue (MB) dyes degradation as a function of time. To evaluatethe effect of the treatment, colorimetric and waterabsorption tests were performed. Moreover, in order to verify the efficiency of coating in inhibiting degradation processes, aging tests have been carried out by evaluating stone resistance to salt crystallization.
In addition, a network based on aluminum and silicon oxides with epoxidic functional groups has been tested as consolidant product. In order to evaluate its effectiveness, colorimetric, water adsorption, compressive strength, aging tests and mercury porosimetry measurements have been performed.
Finally, the performance of an hydrophobic coating applied in association with the consolidanthas been verified by colorimetric and water adsorption tests.
In conclusion, the obtained results showgood photodegradation rates for titaniananosols and good protection properties, especially using the basic preparation. Referring to hybrid organic-inorganic strengthen product and hydrophobic coating, preliminary tests highlight promising applications to the preservation of calcarenites.
L. BERGAMONTI, I. ALFIERI, A. LORENZI, A. MONTENERO, G. PREDIERI, G. BARONE, P. MAZZOLENI, S. PASQUALE, P.P. LOTTICI, Characterization and photocatalytic activity of TiO2 nanoparticles on Modica and Comiso stones, Applied Surface Science 282, 165-173 (2013
Headspace chromatographic analysis for determining low levels of chloroform in human plasma
No full textHeadspace chromatographic analysis for determining low levels of chloroform in human plasm
Characterization of mer and fac isomers of [Ru(2,3-dpp)3][PF6]2 (2,3-dpp = 2,3-bis(2-pyridyl) pyrazine) by 1H and 99Ru NMR spectroscopy. Proton assignment by 2D techniques
No full textWOOD PRESERVATIVE COMPOSITIONS
No full textThe invention relates to a preservative composition comprising a polyamidoamine polymer dissolved or dispersed in an aqueous solvent and/or in an organic solvent, and its use for coating wood, paper, stone and lithoid construction materials (for example travertine, calcareous stones etc.). The preservative composition, which may envisage the addition of metal cations or metal nanoparticles or boric acid, has biocidal properties (anti-fungal, anti-insect, antibacterial, anti-mould) and allows the material to which it is applied to be protected and consolidated
Catalytic hydrogenation of small molecules over metal catalysts derived from (eta-C5H5)NiOs3(mu-H)3(CO)9 and related nickel and osmium clusters supported on gamma-alumina. The effect of the nature and stoicheiometry of the metals.
No full textBehaviour of mono-, bi- and trinuclear group VI, VII and VIII metal carbonyl complexes in high-performance liquid chromatography
No full text- …
