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Trends in Model-Based Coding of Multidimensional Medical Data
No full textThis Chapter presents an overview on the state-of-the-art in the ̄eld of medical image coding. After a brief description of the more representative 2-D and 3-D compression algorithms, a versatile model-based coding scheme for three-dimensional medical is introduced. The potential of the proposed system is due to the fact that it copes with many of the characteristic requirements of the medical imaging field without sacrificing the compression effciency. Among the most interesting features are progressively refinable up-to-lossless quality of the decoded information, object-based functionalities and the possibility to decode a single 2-D im-
age of the dataset. Furthermore, such features can be combined enabling a swift access to any two-dimensional object of any image of interest with refinable quality. The price to pay is an overhead in the bitstream which slightly degrades the compression performance. Though, the possibility to focus the decoding process on a specific region of a certain 2-D image
allows a very effcient access to the information of interest, which can be recovered with the desired up-to lossless quality. We believe this is an important feature for a coding system meant to be used for medical applications, which largely compensates for the eventual loss in compression that could be implied
I sistemi di cost management
No full textIl capitolo riguarda una survey condotta sull'intero territorio nazionale e relativa alle tecniche, agli strumenti e alle metodologie di analisi e gestione dei costi realizzate dalle aziende italiane. R. Silvi ha curato i paragrafi 6.1,6.2,6.3 e 6.4; M. Bartolini i paragrafi 6. 5,6.6, 6.7,6.8,6.10.1 e l'appendice; F.Visani i paragrafi 6.9,6.9.1,6.9.2,6.9.3,6.10.2,6.10.3,6.11 e seguenti
FLUORESCENCE BASED STUDIES ON BETA-AMYLOID MISFOLDING AND AGGREGATION
No full textRecent findings about the relationship between amyloid b-peptide (Ab) accumulation and cognitive decline in Alzheimer's disease (AD) suggest a complex role for Ab in this neurodegenerative process. The transition of Ab soluble monomers to toxic small oligomers involves an initial transition from a non organized/a-helix monomer to a b-sheet rich conformer. This early step represents a suitable target to design new potent inhibitors and obtain effective therapeutics for AD. Moreover, several chaperone molecules are though to accelerate amyloid aggregation, i.e., the enzyme acetylcholinesterase (AChE). Since most of the marketed drugs for AD are AChE inhibitors, the investigation of the inhibitory potency against the AChE-induced amyloid aggregation exerted by anti-cholinesterase agents definitively represents an interesting area of investigation for drug discovery. The in vitro Ab aggregation can be evaluated by a fluorescence-based assay by using Thioflavin T (ThT) as fluorescent dye. More in details, ThT specifically binds to amyloid fibrils (in the beta-sheet conformation) giving rise to an intense specific emission band (lem = 490 nm) in its fluorescent spectrum (1-3). Therefore the increase in the specific fluorescence emission was used to monitor amyloid fibrils formation. Two fluorescence-based assays specifically developed (4,5) for the evaluation of beta-amyloid self- and AChE-induced aggregation were applied to follow the aggregation process as well as to screen for potential inhibitors. The concomitant use of circular dichroism spectroscopy was helpful to set up the optimal experimental conditions and to draw some hypotheses on the mechanism of action of known and new inhibitors.
(1) H. Naiki, K. Higuchi, K. Nakakuki, T. Takeda, Lab. Invest. 1991, 65, 104.
(2) H. LeVine, Protein Sci. 1993, 2, 404.
(3) H. LeVine 3rd, Methods Enzymol. 1999, 309, 274.
(4) M. Bartolini, C. Bertucci, M.L. Bolognesi, A. Cavalli, C. Melchiorre, V. Andrisano, Chembiochem 2007, 8, 2152.
(5) M. Bartolini, C. Bertucci, V. Cavrini, V. Andrisano, Biochem. Pharmacol. 2003, 65, 407
MICRO-IMMOBILIZED ENZYME REACTORS: EVALUATION OF THE APPROPIATE CHROMATOGRAPHIC SUPPORT
No full textIt is here reported the preparation and comparison of different monolithic micro-IMERs (Immobilized Enzyme Reactors) containing covalently immobilized human recombinant acetylcholinesterase (AChE). In particular, following previous studies on AChE-IMERs (1,2), object of this work was the covalent immobilisation of the target enzyme on disk-shaped columns of smaller dimensions (6 x 2 mm, Bed Volume = 56 mL) to increase the enzyme density on the matrix surface.
Since the surface chemistry of the chosen chromatographic support will influence the yield of immobilisation as well as the environment in which the target enzyme will be inserted, the choice of an appropriate support for IMERs development represents an important issue. Moreover, “aspecific” interactions between matrix and substrate and inhibitors will also depend on the chosen material. In this context, CIM disks with different chemistries were chosen for AChE immobilisation, in particular, ethylendiamino (EDA), epoxy and CDI-CIM mini disks were selected. Moreover the introduction of an appropriate spacer arm was evaluated when required.
On-line automated HPLC inhibition studies on a selected series of AChE inhibitors were performed; Aspecific interactions were evaluated and results obtained for the same compound on different CIM-based IMERs were compared.
Results showed that purposely pre-derivatized CDI-based IMER gave promising eluting profile and low aspecific interactions and may therefore represent a valid chromatographic support for the development of monolithic micro-IMERs.
(1) M. Bartolini, V. Cavrini, V. Andrisano: Monolithic micro-immobilized-enzyme reactor with human recombinant acetylcholinesterase for on-line inhibition studies. J Chromatogr A 2004, 1031: 27-34.
(2) M. Bartolini, V. Cavrini, V. Andrisano: Choosing the right chromatographic support in making a new acetylcholinesterase-micro-immobilised enzyme reactor for drug discovery. J Chromatogr A. 2005, 1065:135-44
Modifica del modello fisico - matematico di funzionamento del motore Stirling e relativa analisi parametrica
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