Thermal and electronic properties of macroscopic multi-walled carbon nanotubes blocks.

Massive carpets of well packed, vertically aligned and very long multiwall carbon nanotubes were synthesized by an efficient thermal Chemical Vapour Deposition process. Electrical properties of the material were evaluated, both in terms of "global" characteristics (bulk resistivity) and in terms of "local" properties (Scanning Tunnel Spectroscopy measurements) for as-grown and annealed at different temperatures samples. The behaviour of bulk resistivity as a function of temperature was evaluated in the range 3-300 K, with a four-probe technique. The resistivity shows a linear dependence with the square root of temperature in the investigated range. From the electrical analyses, it was found that the quality of the MWNTs was improved by the annealing process, since the resistivity decreases. Heat transport properties were evaluated by the laser flash technique in order to study thermal diffusivity. Moreover high temperature behavior of the specific heat capacity of single and multi-wall carbon nanotubes, was measured up to 800 K with a Differential Scanning Calorimeter.

Hydrogen adsorption in several types of carbon nanotubes.

In this work, we aim to study the hydrogen adsorption in several kinds of carbon nanotubes grown under different process conditions and to correlate the findings with the morphological microstructure and physical properties of these materials. The growth conditions and the behaviour with respect to hydrogen interaction of various carbon nanotubes are discussed, to establish microstructure-process-property relationships. In particular, we have analyzed several types of carbon nanotubes, namely one single-walled and five multi-walled having different tube diameter (due to different deposition techniques and conditions), different defectiveness and submitted to different surface treatments. To better understand the differences among the various samples, they have been investigated using field emission scanning electron microscopy and high resolution transmission electron microscopy for the morphological and structural characteristics, thermo-gravimetric analysis for the sample purity and Brunauer-Emmett-Teller analysis for the surface area. The experimental measurements on the ability of the different types of carbon nanotubes to adsorb and/or releasing hydrogen have been performed at 77 K with a volumetric Sievert analytical tool. Our findings clearly demonstrate a direct correlation between the exposed surface area and adsorbed hydrogen capacity, which confirms their linear relationship observed previously. For instance, single-walled nanotubes with surface area density of approximately 800 m2/g have showed hydrogen storage of approximately 1.7 wt% at a pressure of 35 atm. Adsorption process seems to be perfectly reversible. The adsorption values have been compared with a simple model, in order to evaluate the potentialities for carbon-based nanomaterials in future hydrogen storage applications.

Hydrogen adsorption in several types of carbon nanotubes.

In this work, we aim to study the hydrogen adsorption in several kinds of carbon nanotubes grown under different process conditions and to correlate the findings with the morphological microstructure and physical properties of these materials. The growth conditions and the behaviour with respect to hydrogen interaction of various carbon nanotubes are discussed, to establish microstructure-process-property relationships. In particular, we have analyzed several types of carbon nanotubes, namely one single-walled and five multi-walled having different tube diameter (due to different deposition techniques and conditions), different defectiveness and submitted to different surface treatments. To better understand the differences among the various samples, they have been investigated using field emission scanning electron microscopy and high resolution transmission electron microscopy for the morphological and structural characteristics, thermo-gravimetric analysis for the sample purity and Brunauer-Emmett-Teller analysis for the surface area. The experimental measurements on the ability of the different types of carbon nanotubes to adsorb and/or releasing hydrogen have been performed at 77 K with a volumetric Sievert analytical tool. Our findings clearly demonstrate a direct correlation between the exposed surface area and adsorbed hydrogen capacity, which confirms their linear relationship observed previously. For instance, single-walled nanotubes with surface area density of approximately 800 m2/g have showed hydrogen storage of approximately 1.7 wt% at a pressure of 35 atm. Adsorption process seems to be perfectly reversible. The adsorption values have been compared with a simple model, in order to evaluate the potentialities for carbon-based nanomaterials in future hydrogen storage applications.

Determination of the wax ester content in olive oils. Improvement in the method proposed by EEC regulation 183/93.

A simpler and faster procedure than the official one described in document IV of European Economic Community Regulation 183/93 is proposed. The wax ester fraction is isolated from triglycerides using a commercially available silica gel column and carbon tetrachloride as eluent. The recovered wax ester fraction, with the addition of a suitable internal standard solution, is analyzed by gas chromatography. A column with a 65% phenyl methyl silicone stationary phase allows a satisfying separation of wax ester fraction in comparison with both a steryl ester and a light fraction eluted before the internal standard. Furthermore, also the single components of the wax ester fraction are suitably separated.

Imaging features of uncommon adrenal masses with histopathologic correlation.

Uncommon adrenal masses include cystic lesions (hydatid cyst, endothelial cyst), solid lesions (hemangioma, ganglioneuroma, angiosarcoma, primary malignant melanoma), and solid fatty lesions (myelolipoma, collision tumor). Most of these lesions do not have specific imaging features. The liquid content of adrenal cysts is clearly demonstrated on ultrasonographic scans, computed tomographic scans, and magnetic resonance images. Nevertheless, the histologic type cannot be predicted except at some stages of hydatid disease in which pathognomonic features are present. The most typical imaging features of hemangioma are phleboliths and enhancement of peripheral vascular lakes. Ganglioneuroma has nonspecific radiologic features, but this diagnosis should be considered in cases with early enhancement of fine septa and progressive filling. The radiologic features of angiosarcoma and primary malignant melanoma are nonspecific. A macroscopic lipid content within an adrenal mass is theoretically characteristic of myelolipoma. This diagnosis should be made with caution, especially when the lipid content is not predominant, because of the possible association with an adenoma.

Characterization of the oligopeptides of Parmigiano-Reggiano cheese soluble in 120 g trichloroacetic acid/l.

The non-protein nitrogen (NPN) of samples of Parmigiano-Reggiano cheese ripened for 6 and 15 months was fractionated by ion-exchange chromatography on a Cu(2+)-Chelex column to separate oligopeptides from free amino acids. Peptide components were isolated by reversed-phase HPLC and identified by fast atom bombardment-mass spectrometry (FAB-MS). Only the NPN fraction of 6 month old cheese samples contained enough peptides to be further characterized. On the basis of FAB-MNS spectral results, 39 oligopeptides were identified, the main components being phosphopeptides. Two sets of both intact and partly dephosphorylated peptides, accounting for a total of 19 phosphopeptides, were formed by the hydrolysis of beta-casein and belonged to regions 1-20 and 6-28 of beta-casein. The formation and potential role of these peptides in cheese is discussed.

[Studies on milk from different species. I. The content of methionine in cow, water buffalo and sheep caseines]. / Reicerche sui latti di diversa specie. I. Il contenuto in metionina delle caseine dei latti di vacca, bufala e pecora

The present paper reports the content of methionine in cow, water buffalo and sheep casein measured according to Maugenet and Coauthors. The following values were obtained: 3,25% in cow; 3,15% in water buffalo; 3,16% in sheep.

[Studies on buffalo milk. XI. Heterogeneity of the buffalo k-casein and the less moving fractions treated with 2-mercaptoethanol (author's transl)]. / Ricerche sul latte di bufala. XI. eterogeneità della k-caseina e delle frazioni meno mobili in presenza di 2-mercaptoetanolo

The heterogeneity of the buffalo k-casein, treated with 2-mercaptoethanol, has been estimated by disk gel-polyacrylamide electrophoresis on 428 caseins isolated from individual milks. The investigation showed six electrophoretic fractions: A, B, C, D, E, F, that, in ten buffalo farms considered formed ten different groups: ABCDEF; ABCDE; ABCEF; ABCE; BCDE; CDEF; BCE; CDE; CEF; and CE. The group ABCDE is the only that is present in all ten farms considered and presents on the whole, the greater number of observations (161). The fraction C is the most abundant. The investigation showed the heterogeneity of the gamma fraction, showing five electrophoretic fractions: A, B, C, D, E, that constitute the nine following groups; ABCDE; ABCD; BCDE; ABD; BCD; ABC; BD; BC and AB. At present a possible correlation to genetic factors seems hazardous.