154 research outputs found
Imaging dinamico con TC e RM
No full textL'evoluzione della Medicina da arte a scienza ha reso evidenti l'enorme complessità dei fenomeni fisiologici e la necessità di disporre di strumenti che consentano di "vedere" e di "misurare" i processi funzionali a vari livelli. L'evoluzione delle tecniche di immagini mediche, in particolare con il ricorso ad agenti di contrasto, fornisce una quantità di informazioni non disponibile sino a una decina di anni or sono. Questo vale non solo per la recente fMRI o per i metodi utilizzanti traccianti radioisotopici (PET, SPECT), ma anche per quelli basati sull'uso di raggi X o di ultrasuoni. Le tecniche hanno raggiunto un tale grado di sofisticazione che nessun singolo individuo è in grado di padroneggiarle: è necessario il contributo coordinato di vati specialisti, non solo medici ma anche bioingegneri e fisici, come già avviene soprattutto nelle neuroscienze e in cardiologia. Nella Scuola, dopo una presentazione delle principali tecniche di formazione delle immagini, in cui saranno esposte anche alcune metodiche che solo potenzialmente sono funzionali, saranno trattati i principali metodi computazionali per l'estrazione di informazioni quantitative dalle immagini e per la loro interpretazione in termini di funzione dell'organo/ tessuto studiato. Dopo aver descritto alcune ricerche su due organi di particolare importanza (cervello e cuore), saranno indicate possibili linee di sviluppo
La Spettroscopia RM: indicazioni generali ed applicazioni nello studio delle neoplasie intracraniche
No full textAnaerobic digestion of winery wastewaters derived from different wine making processes
No full textAnaerobic digestion of winery effluents derived from two different wine making processes was compared in a laboratory scale upflow filter. White winery effluents (WWE) were more easily degradable (average soluble COD removal=92%) than red winery effluents (RWE) (average soluble COD removal = 85%). Differences in the reactor microbial populations for the two effluents were also observed. Both aceticlastic and hydrogenotrophic methanogens in the circulating fractions were significantly higher during the treatment of WWE than during that of RWE. With both wastewaters, the reactor promptly reacted to volumetric organic load (Bv) stress (tripling from 4 to 12 g COD L-1 d(-1)). Following the By perturbation, COD removal decreased to 50%. However, after two weeks the COD removal values were as before perturbation. Volatile fatty acids, especially total VFAs and butyrate measured on the second day after the imposed By perturbation, were good indicators of process imbalance. Coenzyme F-420 determination and scanning electron microscopy revealed the presence of Methanosaeta like cells embedded to extracellular polymers in a uniform slime matrix in the biofilm. The main methanogens observed in the effluents were Methanosarcina and Methanobrevibacter cells
Survey of computed tomography techniques and absorbed dose in Italian hospitals: a comparison between two methods to estimate the dose-length product and the effective dose and to verify fulfilment of the diagnostic reference levels
No full textThe aim of this study was the production of the first Italian survey of radiation dose in computed tomography (CT) prior to the widespread adoption of multislice CT, in order to have a reference point to facilitate later investigation of dose exposure changes brought by this new CT modality. The collected dose data were compared with diagnostic reference levels (DRLs). The agreement between experimental dose evaluation and Monte Carlo (MC) simulations was investigated. The survey was carried out in 29 Italian hospitals, covered 48 CT scanners and 232 examinations. The dose-length product (DLP) and effective dose (E) values were estimated based on MC simulations for seven clinical protocols using the CT-Dose program. Statistical analysis showed a significant difference (p <0.01) in the DLP between the two methods, with MC values being greater than the experimental ones. For E, the MC values were greater in routine head (8.2%), cervical spine (2.7%) and lumbar spine (2.9%) studies. The weighted CT dose index, the DLP and E were always below the DRLs set by the European Community. This dose survey gives a good but incomplete picture of the Italian CT dose situation and may be useful as a reference baseline for defining clinical multislice protocols in the near future
Production of Ceramic Matrix Composites by Means of an Innovative Pilot-Plant for Microwave Assisted Chemical Vapour Infiltration (MWCVI)
No full textEvaluation of “spirotome manual biopsy device” for liver biopsy of iguanas (iguana iguana).
No full textA wavelet packets decomposition algorithm for quantification of in vivo 1H-MRS parameters
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