Using only one histologic preparation and under the light microscope, the simple method described here permits a distinction between osteoid and other tissue components that can be mistaken for osteoid. Osteoid from both normal osteogenesis and osteosarcomas is disclosed by the picrosirius-polarization method as a three-dimensional network of randomly arranged, thin, short, weakly birefringent collagenous structures which shine against a dark background. These morphologic features can be used as a precise diagnostic criterion for the differential diagnosis between osteoid and other materials which resemble osteoid by other staining techniques. This precise characterization of osteoid is of great importance since the presence of osteoid is used as a criterion for the differential diagnosis of osteosarcomas. Not only does this method permit the precise characterization of osteoid but it is also useful for studying collagen distribution in osteosarcomas. In this regard the foregoing results agree with the immunofluorescence observations recorded in the literature.

Ninety-four soft-tissue sarcomas of head and neck occurring among 10,700 malignancies, seen during the period 1953-1980 in the head-and-neck surgical department, were studied with reference to age, sex, ethnic origin, site, histological type and survival. The objective was to review our own experience with sarcomas in these sites seen in the Department of Pathology, A.C. Camargo Hospital. The predominant site was the head. Fibrosarcoma was the most frequent type in adults and rhabdomyosarcoma, located exclusively in the head, was the most frequent in children.

The purpose of this research is to evaluate, at a molecular level, the removal of nitrogen compounds from vacuum gas oil (VGO), which is used as feedstock for fluid catalytic cracking units. Here, a VGO sample was treated with two different adsorbents: an argillaceous material specifically developed for the removal of nitrogen compounds in middle distillate cuts (kerosene and diesel) and a commercial silica adsorbent. Breakthrough curves were built on two temperature levels (80 and 150 °C), containing different rupture times (from 60 to 420 min), to determine their influence on nitrogen compound removal. All samples, produced from each condition of adsorption, were analyzed by positive and negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry [ESI(±)­FT-ICR MS]. Besides FT-ICR MS characterization, the total nitrogen content was monitored. FT-ICR MS indicated that the removal of nitrogen compounds by the clay adsorbent was enhanced when the temperature was higher (150 °C). Conversely, silica has shown a rich adsorption capacity at moderate temperatures (80 °C). This result corroborates the existence of two different adsorption mechanisms. The clay adsorption mechanism is likely a chemisorption process, while the silica adsorption mechanism is related to physisorption. Both processes displayed better performance in short rupture times, for example, at 60 min. Longer rupture times require a saturation of the adsorption process through a packed bed. FT-ICR mass spectra detected a wide range of compounds from m/z 220 to 800, with average molecular weight distributions (M w) that increase as a function of decreasing the total nitrogen content (424 → 711 Da). Class distribution showed a removal preferential of N­[H] and N2[H] compounds with low carbon numbers (

Stringent specifications for sulfur compounds content and the need to use oils with large amount of nitrogen compounds are challenges for fuel producers. Adsorption is an alternative process to remove sulfur and nitrogen compounds and clays are promising adsorbents for this removal. In this work, the adsorption performance of different commercial claysClay A (attapulgite), Clay B (bentonite), and Clay C (bentonite)for the removal of sulfur and nitrogen compounds from a real diesel stream was studied through kinetic and isothermal experiments. The bentonite clays showed the best adsorptive capacity for the removal of sulfur and nitrogen compounds, probably due to the presence of Brønsted acid sites. The highest adsorption capacity was observed for Clay B: 0.174 mol kg −1 for sulfur compounds and 0.127 mol kg −1 for nitrogen compounds. Clay A was more selective to the removal of nitrogen compounds. Equilibrium data showed that adsorbate−absorbate and adsorbate−surface interactions predominate for sulfur and nitrogen compounds, respectively, for Clay A and Clay B.

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