2,587 research outputs found
The effect of ventricular septal defect enlargement on the outcome of Rastelli or Rastelli-type repair
No full textObjectiveOur purpose was to evaluate the effect of ventricular septal defect enlargement on the early and late morbidity and mortality of patients undergoing Rastelli or Rastelli-type operations.MethodsA total of 49 patients who underwent Rastelli or Rastelli-type operations between 1991 and 2007 were included in a retrospective follow-up study. Patients were divided into 2 groups: group A had ventricular septal defect enlargement, and group B did not have ventricular septal defect enlargement for comparison. Risk factor analysis for early or late death included patient-related and procedure-related variables, with failure, arrhythmia, and atrioventricular block as outcome parameters.ResultsMedian age and weight at the time of the operation were 6 years (range, 3 months–22 years) and 17 kg (range, 7–48 kg), respectively. The ventricular septal defect was enlarged in 28 (57%) patients. Ventricular septal defect enlargement showed a significant statistical relation with late ventricular dysfunction, arrhythmia, and residual ventricular septal defect (P = .023, P = .047, and P = .01, respectively, log-rank test). No relation was found between ventricular septal defect enlargement and permanent pacemaker implantation (P = .73, log-rank test). Furthermore, enlargement of the ventricular septal defect did not show any significant effect on the rate of early mortality (P = .69, Cox regression). Kaplan–Meier estimated survival for patients with ventricular septal defect enlargement was 74% at 5 years and 65% at 10 years. Freedom from late death in the group without ventricular septal defect enlargement was 100% at 5 and 10 years and 83% at 15 years. At a median follow-up of 4 years (range, 6 months–16 years), there were 12 late-onset deaths: 11 in group A (n = 28) and 1 in group B (n = 21). Ventricular septal defect enlargement greatly increased the risk of late death (P = .009, Cox regression).ConclusionsSeptal resection in patients undergoing Rastelli or Rastelli-type operations has a substantial effect on late morbidity and is a predictive factor for long-term mortality
MODEL-CALCULATIONS OF CHEMICAL INTERACTIONS .3. ROTATIONAL ENERGY PROFILES IN SIMPLE MOLECULES - EVALUATION, ADDITIVITY AND ROLE OF BOND BOND, BOND LONE-PAIR AND LONE-PAIR LONE-PAIR INTERACTIONS
No full textRotational isomerism in ethane, methylamine, methanol, fluoromethylamine, hydrazine, hydroxylamine, hydrogen peroxide and difluorine dioxide has been analysed using basis sets of symmetrically orthogonalized hybrid AOs. Total vicinal delocalization, which has either an exclusive or a relevant role in determining the rotational energy profile, shows good additivity of the effects of individual interactions and invariance with respect to alternative hybridizations of lone pairs. Bond-sigma-lone-pair interactions which obtain maximum stabilization in their anti-periplanar orientations are significant even in anticlinal and syn-periplanar orientations and contribute, in comparison with bond-bond interactions, a much lower differential energy between eclipsed and staggered conformations. This finding explains interesting features of the rotational energy profiles, like the 'unusual' stability of some eclipsed rotamers. Bond-pi-lone-pair interactions are noticeably effective in their syn(anti)-periplanar orientations and are responsible for the stability of the skew forms of HOOH and FOOF; the exceptionally large OF-O(Ip, pi) interaction in difluorine dioxide is shown to be responsible for the unusually short O-O and long O-F bond lengths, in agreement with a previous explanation where the same structural features had been attributed to the large three-centre four-electron character of the FOO systems
Nuove tecnologie e futuro della città: il governo “aumentato” delle trasformazioni urbane
No full textPer le città del futuro sarà cruciale controllare la trasformazione urbana essendo in grado di salvaguardare al massimo le risorse a disposizione o, in altri termini, minimizzare la produzione di entropia del sistema urbano. La città, considerata come una sistema dinamico e complesso, si modifica nello spazio e nel tempo attivando processi di trasformazione riconducibili alle interazioni fra i sottosistemi urbani ed indotte sia da cause endogene che esogene. La sfida dei prossimi anni sarà quella di predisporre protocolli di governo delle trasformazioni urbane in grado di guidare il sistema nella sua trasformazione su trend di sviluppo sostenibili e compatibili con le risorse a disposizione, ostacolando e/o mitigando i processi di crescita entropica che in passato hanno prodotto effetti nefasti quali l’incontrollato consumo di suolo, l’inquinamento diffuso, la smisurata produzione di rifiuti urbani, etc.. La pre-visione della trasformazione assumerà conseguentemente un ruolo fondamentale dovendo essere efficacemente in grado di valutare l’opportuno impegno di risorse (sociali, economiche, ambientali, etc..). La necessità di superare i canonici modelli della pianificazione urbanistica conduce a considerare nuove possibili protocolli e scenari per il futuro della città; l’approccio sistemico e la pre-visione del cambiamento potrebbero essere considerati gli elementi fondanti dei nuovi processi di governo delle trasformazioni urbane e territoriali. L’innovazione tecnologica (IT) interviene costantemente modificando la struttura dei sottosistemi urbani (si pensi all’impatto sul sistema socio-antropico valutabile attraverso la diffusione dei social) alterando l’interazione fra le parti costituenti, ma offrendo consistenti nuove possibilità per il governo della trasformazione stessa. L’IT non va subita, ma utilizzata, non va “addizionata” alla città, ma “adottata” nella città all’interno dei nuovi processi di governo del sistema urbano. In tale panorama concettuale si inserisce il paper proposto che focalizza, sull’approccio sistemico e sulle diverse possibilità di adozione dell’IT nel processo di pre-visione della città, il proprio contributo presentando la meta-progettazione di un applicativo (LCIM - Live City Information Model) in grado di generare in tempo reale rappresentazioni e simulazioni urbane attraverso le possibilità offerte dalle tecnologie di realtà aumentata e realtà virtuale attualmente disponibili. L’applicazione consente di predisporre un modello virtuale di città, per il quale è possibile realizzare visualizzazioni dinamiche e geolocalizzate, utili alla valutazione ex-ante delle azioni di governo da implementare sul sistema urbano
Fragment-Based Drug Discovery: a Practical Approach
No full textThis book presents a company-based view of the recent progresses in fragment-based drug discovery (FBDD). The book is highly focussed on methodologies.
However, theory is only briefly introduced leaving ample space for the discussion of their implementation in drug discovery campaigns, thereby giving the reader a
clear sense of their applicability and usefulness. Most of the examples come from pharmaceutical drug discovery programs led by the authors themselves,
most of which are from the industry side. The opening chapter provides an overview of the advantages of using chemical fragments in drug discovery.
These include an analysis of the potential advantages over HTS screening, a popular methodology that proved to be problematic in the development of druglike
compounds. Compared with other approaches, fragment-based drug discovery has the potential of finding novel molecules that can be optimized into patentable compounds more easily, have greater molecular diversity, higher hit rates, and are ideally suited for “undruggable” and novel targets
Transcatheter residual ventricular septal defect closure after rastelli operation
No full textWe report on a 17-year-old patient with a residual ventricular septal defect and a significant pressure gradient across the pulmonary homograft after Rastelli-type operation. Device closure of the defect was associated with a considerable reduction of right ventricular hypertension and of the pressure gradient across the right ventricle-to-pulmonary artery conduit. © 2005 Wiley-Liss, Inc
From Han tradition to Tang elegance
No full textThis long paper is the comprehensive essay to the exhibition China at the court of the emperors. Unknown masterpieces from Han Tradition to Tang elegance (25-907), held at Palazzo Strozzi, Florence, in Spring 2008.
It thoroughly explains the development of the arts in China from the Han to the Tang dynasties against the historical and cultural context of the time, underlying the new perspective recently put forward on the basis of the latest archaeological excavations. These have driven scholars to regard the period of division between Han and Tang no longer as a ‘dark’ epoch of unrest, during which the country was politically and culturally fragmented, but instead as a moment of regeneration and flowering of the arts, stimulated by intercultural exchanges with Rome, Persia, India and Central Asia. From this new viewpoint, it appears clear that the great renaissance of the seventh to eighth centuries was the culmination of a long process that had germinated in the second to third centuries
Going beyond errors: Position and Tendency tags in a Learner Corpus
No full textIl processo di etichettatura dei corpora di apprendimento di solito è fortemente debitore delle categorie morfo-sintattiche della lingua di arrivo. In questo saggio si mostrano diversi esempi di come questo approccio non renda affatto ragione delle peculiarità dell'interlingua e non sia in grado di supportare le ipotesi acquisizionali sulla stadiazione dei principali fenomeni di sintassi e semantica verbal
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