Analisi del processo di estrusione di leghe leggere con il software Qform: validazione e previsione della microstruttura

Il gruppo di tecnologie e sistemi di lavorazione del Dipartimento di Ingegneria Industriale, D.I.N, dell’Università di Bologna ha compiuto in collaborazione con il Dipartimento IUL della TU di Dortmund, negli ultimi anni, due campagne sperimentali effettuando processi di estrusione di leghe di alluminio. Nella prima, utilizzando leghe AA6060 e il metodo della visioplasticità, sono stati raccolti dati volti a ricavare le condizioni di attrito di tali processi, tramite confronto con valori ottenuti in simulazioni agli elementi finiti. Nella seconda, utilizzando invece una lega AA6082, è stata valutata la microstruttura al fine di permettere, tramite programmi agli elementi finiti, la determinazione di correlazioni fra variabili che prevedano la dimensione della microstruttura della lega stessa a seguito di lavorazioni per deformazione plastica. Basandosi quindi su queste prove sperimentali e utilizzando il software “QuantorForm versione 7.2.4”, è stato svolto il lavoro di tesi finalizzato a conseguire i seguenti obiettivi: • individuare il modello di attrito che si sviluppa nei processi di estrusione analizzati per la lega di alluminio AA6060; • determinare i parametri di settaggio ottimale del software, confrontando i risultati ottenuti nelle simulazioni con quelli sperimentali; • determinare le curve che descrivono la dimensione di un grano cristallino di AA6082 in funzione della deformazione; • implementare come subroutine in Qform, tramite l’utilizzo del linguaggio “Lua”, il modello di microstruttura ottenuto.

Bologna, la citta dei flussi: Riqualificare e connettere tra architettura e movimento

La città di Bologna, la storia, i flussi e le connessioni. Questo progetto di gruppo nasce dalla necessità di ripensare il ruolo dell’infrastruttura nella contemporaneità e nell’atteggiamento che l’architettura può assumere di fronte alle rinnovate priorità delle città italiane che, tra espansione demografica, monumenti e centri storici da preservare, nuove reti di comunicazione e scambio delle informazioni, necessitano sempre pi�� di una pianificazione che prenda in analisi il passato, interpreti il presente e si ponga l’obiettivo primario di dialogare con il futuro. Il capoluogo Emiliano è collocato in una posizione strategica per le comunicazioni d i trasporti, tenendo uniti gli estremi dello stivale e svolgendo un ruolo di snodo a cui oggi la penisola Italiana non può in alcun modo rinunciare. Ogni giorno una quantità spropositata di pendolari e viaggiatori è indotta nella città concentrandosi in un primo momento nell’area della stazione ferroviaria e dei piazzali antistanti, per poi distribuirsi all’interno del tessuto urbano, chi utilizzando il sistema di rete tramviaria, chi a piedi o in bicicletta. L’intento principale del masterplan proposto è quindi valutare un range di informazioni supplementari ai tradizionali studi urbani. Si è notato come le aree pi�� degradate della città (spesso limitrofe ad infrastrutture consegnate al comune senza valutarne l’integrazione e l’impatto urbano e ambientale) manchino di una circolazione costante e di attività. Si è identificato nelle migliaia di soggetti che ogni giorno giungono a Bologna usufruendo dei servizi delle Ferrovie dello Stato la linfa vitale di un’importante parte della città. Poiché progettare per un futuro prossimo è pensare a un presente in grado di accettare i propri limiti e assimilare le aberrazioni del passato, rifacendosi ad un immaginario che non può che sconfinare i paradigmi prefissati che hanno portato ad uno status irrisolto ma non irrisolvibile.

Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells

The past decade has seen significant increases in combustion-generated ambient particles, which contain a nanosized fraction (less than 100 nm), and even greater increases have occurred in engineered nanoparticles (NPs) propelled by the booming nanotechnology industry. Although inhalation of these particulates has become a public health concern, human health effects and mechanisms of action for NPs are not well understood. Focusing on the human airway smooth muscle cell, here we show that the cellular mechanical function is altered by particulate exposure in a manner that is dependent upon particle material, size and dose. We used Alamar Blue assay to measure cell viability and optical magnetic twisting cytometry to measure cell stiffness and agonist-induced contractility. The eight particle species fell into four categories, based on their respective effect on cell viability and on mechanical function. Cell viability was impaired and cell contractility was decreased by (i) zinc oxide (40-100 nm and less than 44 microm) and copper(II) oxide (less than 50 nm); cell contractility was decreased by (ii) fluorescent polystyrene spheres (40 nm), increased by (iii) welding fumes and unchanged by (iv) diesel exhaust particles, titanium dioxide (25 nm) and copper(II) oxide (less than 5 microm), although in none of these cases was cell viability impaired. Treatment with hydrogen peroxide up to 500 microM did not alter viability or cell mechanics, suggesting that the particle effects are unlikely to be mediated by particle-generated reactive oxygen species. Our results highlight the susceptibility of cellular mechanical function to particulate exposures and suggest that direct exposure of the airway smooth muscle cells to particulates may initiate or aggravate respiratory diseases.

Safety and Functional Outcome of Thrombolysis in Dissection-Related Ischemic Stroke: A Meta-Analysis of Individual Patient Data

The safety and efficacy of thrombolysis in cervical artery dissection (CAD) are controversial. The aim of this meta-analysis was to pool all individual patient data and provide a valid estimate of safety and outcome of thrombolysis in CAD.

Cost-effectiveness of pharmacogenetic testing to predict treatment response to angiotensin-converting enzyme inhibitor

OBJECTIVE: This study aimed to assess the potential cost-effectiveness of testing patients with nephropathies for the I/D polymorphism before starting angiotensin-converting enzyme (ACE) inhibitor therapy, using a 3-year time horizon and a healthcare perspective. METHODS: We used a combination of a decision analysis and Markov modeling technique to evaluate the potential economic value of this pharmacogenetic test by preventing unfavorable treatment in patients with nephropathies. The estimation of the predictive value of the I/D polymorphism is based on a systematic review showing that DD carriers tend to respond well to ACE inhibitors, while II carriers seem not to benefit adequately from this treatment. Data on the ACE inhibitor effectiveness in nephropathy were derived from the REIN (Ramipril Efficacy in Nephropathy) trial. We calculated the number of patients with end-stage renal disease (ESRD) prevented and the differences in the incremental costs and incremental effect expressed as life-years free of ESRD. A probabilistic sensitivity analysis was conducted to determine the robustness of the results. RESULTS: Compared with unselective treatment, testing patients for their ACE genotype could save 12 patients per 1000 from developing ESRD during the 3 years covered by the model. As the mean net cost savings was euro 356,000 per 1000 patient-years, and 9 life-years free of ESRD were gained, selective treatment seems to be dominant. CONCLUSION: The study suggests that genetic testing of the I/D polymorphism in patients with nephropathy before initiating ACE therapy will most likely be cost-effective, even if the risk for II carriers to develop ESRD when treated with ACE inhibitors is only 1.4% higher than for DD carriers. Further studies, however, are required to corroborate the difference in treatment response between ACE genotypes, before genetic testing can be justified in clinical practice.

Catch-up growth in autosomal dominant isolated growth hormone deficiency (IGHD type II)

OBJECTIVE: Data on the GH-induced catch-up growth of severely GH-deficient children affected by monogenetic defects are missing. PATIENTS: Catch-up growth of 21 prepubertal children (6 females, 15 males) affected with IGHD type II was analyzed in a retrospective chart review. At start of therapy, mean age was 6.2 years (range, 1.6-15.0), mean height SDS was -4.7 (-7.6 to -2.2), mean IGF-I SDS was -6.2 (-10.1 to -2.2). GH was substituted using a mean dose of 30.5microg/kg*d. RESULTS: Catch-up growth was characterized by a mean height gain of +0.92, +0.82, and +0.61 SDS after 1, 2, and 3 years of GH therapy, respectively. Mean height velocities were 10.7, 9.2 and 7.7cm/year during the first three years. Mean duration of complete catch-up growth was 6 years (3-9). Mean height SDS reached was -0.97 (-2.3 to +1.1), which was within the range of the estimated target height of -0.60 SDS (-1.20 to -0.15). The younger and shorter the children were at start of therapy the better they grew during the first year independent of the dose. Mean bone age was delayed at start by 2.1 years and progressed by 2.5 years during the first two years of therapy. Incomplete catch-up growth was caused by late initiation or irregular administration of GH in four cases. CONCLUSIONS: Our data suggest that GH-treated children with severe IGHD show a sustained catch-up growth over 6 years (mean) and reach their target height range. This response to GH is considered to be characteristic for young children with severe growth retardation due to IGHD.

Surface Deformations as Indicators of Deep Ebullition Fluxes in a Large Northern Peatland

Peatlands deform elastically during precipitation cycles by small (+/- 3 cm) oscillations in surface elevation. In contrast, we used a Global Positioning System network to measure larger oscillations that exceeded 20 cm over periods of 4 - 12 hours during two seasonal droughts at a bog and fen site in northern Minnesota. The second summer drought also triggered 19 depressuring cycles in an overpressured stratum under the bog site. The synchronicity between the largest surface deformations and the depressuring cycles indicates that both phenomena are produced by the episodic release of large volumes of gas from deep semi-elastic compartments confined by dense wood layers. We calculate that the three largest surface deformations were associated with the release of 136 g CH4 m(-2), which exceeds by an order of magnitude the annual average chamber fluxes measured at this site. Ebullition of gas from the deep peat may therefore be a large and previously unrecognized source of radiocarbon depleted methane emissions from northern peatlands.

Matrix metalloproteinase inhibition lowers mortality and brain injury in experimental pneumococcal meningitis

Pneumococcal meningitis (PM) results in high mortality rates and long-lasting neurological deficits. Hippocampal apoptosis and cortical necrosis are histopathological correlates of neurofunctional sequelae in rodent models and are frequently observed in autopsy studies of patients who die of PM. In experimental PM, inhibition of matrix metalloproteinases (MMPs) and/or tumor necrosis factor (TNF)-converting enzyme (TACE) has been shown to reduce brain injury and the associated impairment of neurocognitive function. However, none of the compounds evaluated in these studies entered clinical development. Here, we evaluated two second-generation MMP and TACE inhibitors with higher selectivity and improved oral availability. Ro 32-3555 (Trocade, cipemastat) preferentially inhibits collagenases (MMP-1, -8, and -13) and gelatinase B (MMP-9), while Ro 32-7315 is an efficient inhibitor of TACE. PM was induced in infant rats by the intracisternal injection of live Streptococcus pneumoniae. Ro 32-3555 and Ro 32-7315 were injected intraperitoneally, starting at 3 h postinfection. Antibiotic (ceftriaxone) therapy was initiated at 18 h postinfection, and clinical parameters (weight, clinical score, mortality rate) were recorded. Myeloperoxidase activities, concentrations of cytokines and chemokines, concentrations of MMP-2 and MMP-9, and collagen concentrations were measured in the cerebrospinal fluid. Animals were sacrificed at 42 h postinfection, and their brains were assessed by histomorphometry for hippocampal apoptosis and cortical necrosis. Both compounds, while exhibiting disparate MMP and TACE inhibitory profiles, decreased hippocampal apoptosis and cortical injury. Ro 32-3555 reduced mortality rates and cerebrospinal fluid TNF, interleukin-1β (IL-1β) and collagen levels, while Ro 32-7315 reduced weight loss and cerebrospinal fluid TNF and IL-6 levels.

Ueber die politische, religi��se und moralische Verfassung der Juden

von einem Kosmopoliten [d.i. Julius Friedrich Knüppeln]

Prinzipien-Entwurf für die Genossenschaft für Reform im Judenthum

Versuch von A. Rebenstein [d.i. Aaron Bernstein]