7 research outputs found
Zinc recovery during refractory ore biooxidation by an indigenous consortium
Two enrichment cultures (one iron oxidizing and one sulfur oxidizing) obtained from an acid mine drainage were physiological and molecular characterized; the first of them showed 99% 16S rRNA gene sequence similarity with Leptospirillum ferrooxidans, while the sulfur oxidizing species was highly related to Acidithiobacillus ferrooxidans and Acidithiobacillus ferrivorans sequences although, unlike them, the species in the enrichment culture does not seem to be able to oxidize iron. The consortium constituted by both enrichment cultures achieved a successful biooxidation of Hualilan ore allowing the increase of gold recovery up to 96.4 % in the best culture condition (low pulp density in 1K medium). At the same time, this condition showed an effective zinc bioleaching (up to 86 %) although the recovery was much higher in cultures with initially supplemented iron; kinetics studies suggested that bioleaching rate in 1K medium at low pulp densities is controlled by diffusion through a layer mainly constituted by jarosite (rather than sulfur) which was detected in X-ray diffraction diagrams. The recovery of zinc as subproduct of the pretreatment to optimize gold recovery would also allow decrease the metallic charge of the leachates from the biooxidation tanks which is an environmental advantage.Centro de Investigación y Desarrollo en Fermentaciones Industriale
Vibrational analysis of trans N-methyl-acetamide in aqueous solution from ab-initio molecular dynamics
Manifestazione neoplastiche esofagee secondarie in gengiva derente. Un caso clinico
Gli autori descrivono un caso di lesione metastatica, in sede
gengivale, in un uomo di 47 anni con storia di patologia neoplastica dell’esofago. La raccolta dei dati anamnestici e clinici del paziente assume una notevole rilevanza nella diagnosi di tali lesioni, poiche le metastasi per via orale possono essere asintomatiche o determinare dolore, ulcere, parestesia e sanguinamento. Sono importanti gli esami radiografici
come ortopantomografia, tomografia computerizzata del massiccio facciale e scintigrafia per valutare e stadiare la lesione e per scegliere un’eventuale terapia chirurgica.
Le lesioni del cavo orale dovute a tumori primitivi
di altri organi e distretti sono insolite; rappresentano meno dell’1% di tutte le neoplasie della cavita orale. A causa della loro rarita, i tumori metastatici nella regione orale sono di non facile diagnosi da parte del clinico. In accordo con l’oncologo e il radioterapista, in questo caso sono state eseguite sedute di radioterapia mirata per ridurre la massa tumorale e il
sanguinamento spontaneo