705 research outputs found
MgO nanoparticles synthesized starting from an innovative one-step process
No full textNanosized MgO is a functional material showing a great promise as destructive adsorbent for toxic chemical agents, unique optical electronic, magnetic, thermal, and mechanical properties, as well as in good bactericidal performance in aqueous environments and in the cancer therapy. In this study, MgO nanoparticles are obtained by thermal decomposition of nanosized Mg(OH)2, which are synthesized by means of an innovative, time and cost-effective, scalable, and patented method. The nanoparticles are characterized by means of several techniques such as thermal analyses, X-ray diffraction analysis, infrared spectroscopy, transmission electron microscopy, atomic force microscopy, and surface area measurements (BET). After a pseudomorphic decomposition of the hydroxide precursor, pure and crystalline MgO nanoparticles are obtained. These nanoparticles are roughly spherical, monodispersed, and monocrystalline, having size ≤10 nm. Moreover, they exhibited a surface area up to 178 m2/g, revealing a bimodal mesoporous distribution with the important part of the pores with dimensions peaked at 4.87 nm
In vitro effect of lymphoblastoid alpha-interferon on subpopulations of effector cells mediating cytotoxicity for autologous hepatocytes in hepatitis B and non-A, non-B.
No full textMorpho-pomological and chemical characterization of pomegranate (Punica granatum L.) genotypes in Apulia region, Southeastern Italy
No full textA recent increasing demand in Western countries for pomegranate products by consumers is especially supported for the nutritional and medicinal characteristics, due to the antioxidant properties of this fruit. Some studies have been published on the morphological and biochemical characteristics of pomegranate fruits in some Mediterranean countries, but little information is available about the genotypes present in Italy and in particular in Apulia (Southeastern region of Italy). This study (2008–2009) evaluated morpho-pomological and chemical parameters of eight pomegranate genotypes localized in private small orchards. Significant differences were observed among the pomegranate genotypes for many of the parameters investigated. In particular, fruit weight ranged from 168.9 g (SouMol) to 574.9 g (SouOst), ◦Brix from 14.7 (ComTri) to 18.0 (SouMol), titratable acidity from 5.4 (ComMol) to 25.0 (SouTri) g/L. SouMol showed the highest polyphenols (97.1 mg/L) and vitamin C (236.3 mg/L) contents. Oil content of the seeds was between 5.90% and 10.30%, no differences have been observed for the fatty acid composition with conjugated linoleic acid (CLA) isomers as the most abundant fraction (81.23%). Considering all the evaluated parameters, and especially those referring to the organoleptic characteristics and antioxidants content, it must be stated that the best genotypes worthy to be considered from agricultural and industrial points of view were AdeSgi for fresh market and SouOst for the juice industry
New sustainable, scalable and one-step synthesis of iron oxide nanoparticles by ion exchange process
No full textThis work introduces an innovative, sustainable, and scalable synthesis of iron oxides nanoparticles (NPs) in aqueous suspension. The method, based on ion exchange process, consists of a one-step procedure, time and energy saving, operating in water and at room temperature, by cheap and renewable reagents. The influence of both oxidation state of the initial reagent and reaction atmosphere is considered. Three kinds of iron nanostructured compounds are obtained (2-lines ferrihydrite; layered-structure iron oxyhydroxide δ-FeOOH; and cubic magnetite), in turn used as precursors to obtain hematite and maghemite NPs. All the produced NPs are characterized by a high purity, small particles dimensions (from 2 to 50 nm), and high specific surface area values up to 420 m2/g, with yields of production >90%. In particular, among the most common iron oxide NPs, we obtained cubic magnetite NPs at room temperature, characterized by particle dimensions of about 6 nm and a surface area of 170 m2/g. We also obtained hematite NPs at very low temperature conditions (that is 2 h at 200 °C), characterized by particles dimensions of about 5 nm with a surface area value of 200 m2/g. The obtained results underline the strength of the synthetic method to provide a new, sustainable, tunable, and scalable high-quality production
Dynamic aspects of the stereochemistry of phenothiazines in solution : Part 2. Segmental motion and conformational analysis of the side-chain in promazines
No full textSome promazines and the model compound NN-dimethyl-3-phenylpropylamine have been studied, as protonated and unprotonated species, by 1H and 13C n.m.r. spectroscopy. 13C T1 relaxation times have shown that the mobility of the dimethylaminopropyl chain in chloroform solution varies depending on whether the chain is protonated or unprotonated, and whether it is attached to a phenyl or to a tricyclic system. Segmental motions were also detected in two compounds. The conformation of the side-chain has been deduced for different solvents. Remarkably, for protonated promazines the preferred conformations are gauche for the Cα-Cβ fragment and trans for the Cβ-Cγ in chloroform as well as in water solution, whereas the model compound exists preferentially in the fully extended trans–trans-conformation. In dioxan and in DMSO the population of the αβ-gauche forms decreases. The presence and the nature of the 2-substituent do not appear to have any effect, whereas the tricyclic system is predominant in the stabilization of the αβ-gauche form. This has been related to the ability of these molecules to aggregate in solution with a vertical stacking-type association
Mediterranean soil fertility management for economically feasible and environmentally sustainable production of organic tomatoes
No full textMediterranean soils are naturally characterized by low organic matter. Soil organic matter is an indicator of soil health, and it directly affects soil physical, chemical and biological fertility. Preserving soil health also represents one of the main objectives of organic farming. However, each organic fertility management strategy has different effects on soil properties and specific mechanisms of action. Therefore, the aim of this research was to evaluate the effects of different fertility managements on physical, chemical, biological and biochemical indicators of soil health and to identify their potential economic impacts. Despite the low doses, treatments containing humates presented the highest yield, approximately 55 Mg ha-1, and increased soil organic carbon content of at least 1 g kg-1. These results indicate a potential environmental sustainability of the two humate products in comparison with compost and fertilizers admitted in organic agriculture
Conformational analysis of N-acetyldaunomycin in solution. A transient 1H nuclear Overhauser effect study of the glycosidic linkage geometry
No full textThe conformational properties of daunomycin (1) and several analogues (2)–(16) have been investigated by 1H n.m.r. in different solvents, CDCI3, D2O, DMSO, dioxane, and pyridine. From H,H three-bond and long-range coupling constants, the geometry of ring A in each solvent has been determined, through a Karplus–Altona equation, which includes a correction for the substiuent electronegativity. Conformers 9H8, 8H9, 9S, S9, and S8 have been found in solution, and in several cases, especially in DMSO, more than one conformer is present at equilibrium. The equilibrium is always fast compared with n.m.r. times and the relative populations of each conformer have been calculated from experimental and model coupling constants by using a least-squares procedure. Two factors have been recognized to be responsible for the shape of ring A: the intramolecular hydrogen-bond 9–OH O(7) and steric interactions between peri substituents on the A and B rings. Evidence for this hydrogen-bonding has been obtained by dilution experiments, and, for the peri interactions, by evaluating the substituent effects on the conformational preference. Other intramolecular hydrogen bonds have been proved not to exist in solution. The influence of the solvents on the shape of ring A has also been studied. All the results are discussed and compared with those obtained in the solid phase. Daunosamine moiety has also been analysed, and the conformation of the sugar ring is always 1′C4. (L) in all the solvents examined
13C nuclear magnetic resonance spectroscopy of nitrogen heterocycles. Part 4. intra-extra Configuration of the N-acetyl group in phenothiazine and related systems with a "butterfly" shape
No full textNitrogen lone-pair delocalization into aromatic rings has been studied for phenothiazine, N-acetylphenothiazine, and related tricyclic systems with a ‘butterfly’ conformation, by using 13C n.m.r. spectroscopy. Pyridazo[4,5-d][1,4]benzothiazines, phenoxazines, acridane, and simple model compounds such as diphenylamine, 2-methylthioaniline, and their corresponding N-acetyl derivatives were examined. The preferred configuration of the N-acetyl group has been determined for CDCl3 and Me2SO solutions. Nitrogen lone-pair delocalization of the N-acetyl group into the aromatic system is strongly hindered for all tricyclic compounds, and greatly reduced for N-acetyldiphenylamine and also for 2-methylthioacetanilide in Me2SO. For this last compound, the decrease of conjugation is due to a solvent-induced change of conformation; for tricyclic systems it is a consequence of the preferred extra-configuration of the N-acetyl group
Antibody-negative chronic hepatitis C virus infection in immunocompetent children
No full textAntibody-negative hepatitis C virus (HCV) infection, defined by the presence of HCV viremia in the absence of a serological response to HCV, was detected in two immunocompetent and symptom-free children; each had a history of exposure to blood products. HCV infection may occasionally explain cryptogenic elevation of aminotransferases, even in he absence of serum anti-HCV. HCV-RNA shoud be investigated in these cases, particularly in the presence of previous exposure to blood products
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