1,354,085 research outputs found
Valutazione della funzionalità epatica e renale dopo Anestesia Endovenosa Bilanciata
No full textDopo molti anni di impiego quotidiano di una tecnica di anestesia bilanciata endovenosa, gli autori hanno ritenuto opportuno studiare alcuni parametri della funzionalità epatica e renale per chiarire se dopo l'intervento vi fosse una qualche alterazione di queste funzion
Riduzione dei movimenti lenti di versante mediante barriere di protezione costituite da pali accostati
No full textNella tesi si è studiata l’efficacia di file di pali passivi come interventi di mitigazione di movimenti di versante lenti e caratterizzati da superfici di scorrimento poco profonde. Lo studio ha riguardato, in particolare, la definizione dei meccanismi di interazione tra il corpo di frana, il sistema di pali e lo strato di terreno stabile al variare delle caratteristiche geometriche e meccaniche del problema analizzato, delle ipotesi costitutive adottate per descrivere il comportamento meccanico del terreno e delle condizioni di vincolo assunte per i pali. L’efficienza dell’intervento è stata valutata in termini di riduzione degli spostamenti calcolati a monte e a valle della barriera rispetto allo spostamento imposto, considerandone la dipendenza dall'interasse tra i pali della fila, dalle proprietà meccaniche del corpo di frana e da quelle della formazione stabile di base. Lo studio di interazione ha permesso, inoltre, di stimare le sollecitazioni di taglio e momento flettente agenti sui pali, al fine di un adeguato dimensionamento dell’intervento.
Le analisi sono state condotte in condizioni tridimensionali per descrivere correttamente la natura discontinua dell’intervento. Sono quindi commentati i limiti relativi all'utilizzo di più semplici modelli bidimensionali, rappresentando, in particolare, l’interazione pali-terreno in un piano parallelo al piano campagna. Le analisi di interazione 2D e 3D sono state eseguite con il codice di calcolo alle differenze finite FLAC
Modificazione di alcune componenti del quadro lipoproteico dopo infusione endovenosa con Diprivan per interventi condotti in anestesia endovenosa totale
No full textSono ormai trascorsi 6 anni da quando il propofol ( Diprivan),ha trovato largo impiego in numerose metodiche anestesiologiche di sedazione e anestesia. Questa nuova formulazione si basa essenzialmente sulla sostituzione del vecchio solvente (Cremophor EL) con una emulsione di olio di soia in veicolo acquoso con ph neutro della soluzione così ottenuta
Anestesia bilanciata endovenosa:valutazione clinica dei vantaggi e limiti di una metodica impiegata in 8929 casi di chirurgia generale
No full textda oltre 10 anni abbiamo adottato un tipo di anestesia endovenosa bilanciata utilizzando come unica integrazione analgesica inalatoria N2O in percentuale del 66% in O2 .In questo lungo periodo abbiamo saggiato diverse associazioni farmacologiche alternative per realizzare il binomio NEUROLETTICO+ANALGESICO, ma ,la maggior parte dei nostri casi è stata trattata con la ormai classica associazione Droperidolo-Fentanil
IL LUNGO VIAGGIO DI ZIA DALL'AFGHANISTAN ALL'ITALIA
No full textIl testo narra la vicenda di Zia, un ragazzo Azara fuggito dall'Afghanistan in tenera età. Non è un romano e neppure, come forse potrebbe apparire, la fredda "cronaca" della sua fugava un paese - l'Afghanistan - in cui ogni libertà è negata. Troppi elementi restano oscuri, troppi interrogativi aperti...Queste pagine son piuttosto la discesa agli inferi di un adolescente che, iniziando a ricreare, a nominare i suoi ricordi, impara contemporaneamente a specchiar dil proprio dolore nella gioia di chi si sta occupando di lui. Chi ha trascritto si è limitato a mettere semplicemente sui carta tutto ciò che adirava nella mente di Zia, i suoi sogni, le risa ed i pianti, la paura, la nostalgia, i singhiozzi che ogni tanto crepitavano in gola nel ricordare quando ancora sapeva essere normalmente gioioso ed allegro, quando amava la vita e viveva felice con i suoi genitori
Efficiency of Piles Stabilizing Slopes in Fine-Grained Soils
No full textEqually spaced piles can be designed to ensure the stability of a slope with a desired safety factor or to restrain slow slope movements to prevent damage to existing structures. The piles are usually arranged in lines installed transversally to soil movements or in groups of limited extension in a plan according to their stabilizing or protective function. A numerical study has been performed to analyze the role of some design parameters in the efficiency of equally spaced piles, adopting two-dimensional (2D) and three-dimensional (3D) finite-difference (FD) models. Plane strain models have been used to study the soil arching mechanism and the associated stress transfer from the yielding soil to the stabilizing piles, while 3D numerical analyses have been performed to evaluate the efficiency of pile groups. The effect of varying pile spacing, pile embedded length, soil mechanical properties, and sloping ground conditions have been investigated for two-layer slopes assuming fixed or unconstrained piles. The outcomes of the parametric study made it possible to derive a simple analytical relationship to quantify the resisting contribution provided by the piles in an infinite slope. The paper shows that the proposed approach, even though limited to the ranges of the adopted parameters, can be used for a preliminary design of stabilizing piles to ensure the desired increase in the slope safety factor, as well as to achieve the desired reduction of downhill slope movements
A mitigation technique to reduce ground settlements induced by tunnelling using diaphragm walls
No full textGround movements due to the excavation of shallow tunnels may cause damage or loss of functionality to nearby buildings: embedded diaphragm walls pre-installed between the tunnel and the building can be effective in reducing these movements thus preventing damage on existing structures. Plane strain finite element analyses are first presented in the paper in which a continuous diaphragm made by adjacent panels was modelled to evaluate the effects of different geometrical and mechanical parameters. For a limited set of these parameters, 3D FE analyses were also performed maintaining a plane strain excavation scheme to evaluate the effectiveness of an infinite diaphragm made by closely spaced piles. A 3D study is finally presented in which the horizontal diaphragm length needed to attain the same efficiency provided by an infinite diaphragm is evaluated. Completion of tunnel construction was assumed in both 2D and 3D studies
Diaphragm wall as a mitigation technique to reduce ground settlements induced by tunnelling
No full textThe adoption of mitigation techniques in addition to the accurate control of excavation stages is often required to contain soil movements caused by the construction of new underground railway lines, thus preventing damage or loss of functionality to existing buildings and structures. The mitigation technique studied in this paper consists of an embedded diaphragm wall pre-installed between the tunnel and an existing building. Two- and three-dimensional analyses were performed to define the most convenient dimensions of the diaphragm wall, related to tunnel diameter and cover. 3D analyses are fundamental to consider the influence of the planar extension of the diaphragm, useful for verifying its compatibility with the built environment
[Clinical evaluation of a method of total intravenous anesthesia in various types of surgical patients].
No full textInhaled anaesthetic agents (gases and vapours) may be detrimental to the health of patients and cause a chronic operating room air pollution. Therefore, the authors expound the results obtained using a total intravenous anesthesia technique including propofol to induce and maintain hypnosis integrated with pancuronium bromide, droperidol and fentanyl. Patients have been ventilated with mixture of air and oxygen 30%. This technique has been tried in 60 cases of various kind of elective surgical patients obtaining very good results: in 40% of cases the anaesthetic level was excellent, while in some patients it was not adequate on account of intraoperative pressure increases. This technique of total intravenous anesthesia deserves wider use on account of the good tolerance to propofol, the excellent awakening without postoperative troubles (nausea and vomiting)
Efficiency of embedded barriers to mitigate tunnelling effects
No full textGround displacements caused by underground excavations in densely urbanised areas often requires the adoption of protective techniques to prevent damage to existing buildings. When the tunnel passes to the side of a potentially affected building, tunnelling-induced settlements can be reduced pre-installing a protective barrier between the tunnel and the building. Usually, this mitigation technique is implemented in practice based on empirical knowledge rather than as a result of a rational design process. This paper presents a numerical study to evaluate the efficiency of different schemes of embedded barriers, using numerical analyses as a tool to understand the main mechanisms of soil-barrier interaction. Two- and three-dimensional FE analyses were carried out assuming a continuous embedded diaphragm wall or a discontinuous piled wall. The barrier was assumed of either infinite or finite horizontal extension, to evaluate the minimum extension needed to obtain in a given section a settlement reduction similar to that attained under plane strain conditions. The effects induced by wall installation and those associated to the presence of a pre-existing building were also accounted for. The results of the analyses permitted to recognise the main factors affecting the efficiency of a protective barrier, providing some guidance for a rational design of the intervention
- …
