Studio della resistenza alla fatica di contatto di acciai sinterizzati trattati termicamente

In questo studio viene proposto un approccio conservativo per la previsione del comportamento a fatica dicontatto di due acciai sinterizzati e trattati termicamente. Il modello utilizzato è incentrato sulla nucleazionedella cricca di fatica, che avviene solamente in presenza di fenomeni di deformazione plastica locale. Ladeformazione plastica locale, a sua volta, si verifica quando lo sforzo massimo è superiore alla resistenza allosnervamento del materiale negli strati subsuperficiali. Sforzo massimo e resistenza alla deformazione plasticasono stati calcolati considerando le peculiarità della microstruttura dei sinterizzati porosi: la distribuzionedella dimensione e del fattore di forma dei pori, che influenzano la frazione di sezione utile resistente, el’eterogeneità microstrutturale e della microdurezza, che influenzano la resistenza allo snervamento dellamatrice. Il modello previsionale è stato validato sperimentalmente

QuantiFERON-TB performs better in children, including infants, than in adults with active tuberculosis: A multicenter study

Immunological tests, including the QuantiFERON-TB Gold In-Tube (QFT-IT) assay, represent an important aid for diagnosing active tuberculosis (TB) and latent TB infections in children, but concerns about their use in children <5 years of age persist. This is a multicenter retrospective study comparing a population of 226 children to 521 adults with pulmonary or extrapulmonary TB. The aim was to evaluate the QFT-IT performance, analyzing both qualitative and quantitative results, according to age, birthplace, and disease localization. Compared to culture, QFT-IT sensitivity was 93.9%, 100%, and 94.4% in children <= 2, 2 to 5, and 5 to 16 years of age, respectively, and was significantly higher than that in adults (81.0%) (P < 0.0001). The rate of indeterminate test results for children (2.2%) was significantly lower than that for adults (5.2%) (P < 0.0001). In children, QFT-IT sensitivity was not affected by disease localization or birthplace (Italy born versus foreign born). Interferon gamma (IFN-gamma) values in response to TB antigen and mitogen were significantly higher in children than in adults (TB antigen, median of 10 versus 1.66 IU IFN-gamma/ml; mitogen, median of 10 versus 6.70 IU IFN-gamma/ml; P < 0.0001). In summary, this study supports the use of QFT-IT as a complementary test for the diagnosis of pediatric TB even under 2 years of age. Our observations could be applicable to the new version of the test, QuantiFERON-TB Gold Plus, which has recently been shown to have similar sensitivity in active TB, although data in children are still lacking

The Professional Doctorate

In the light of significant national and international policy change impacting institutions of higher education and higher education’s role in the emerging world economy (Friedman, 2005), it is unsurprising that new interest in the doctoral education field has prompted changing conceptualisations of what doctoral work is. At the level of programme development and provision, universities are increasing the range of practices and number of doctorates on offer

Synthesis and characterization of zeolite-encapsulated metalloporphyrins

Metalloporphyrins of Fe(III) and Cu(II) were prepared inside the large pores of the zeolite NaY by a process of sequential introduction of components followed by assembly inside the void space of the zeolite. The appropriate process chosen for the porphyrin synthesis was using the propionic acid solvent for reaction between pyrrole and benzaldehyde and this solvent was not destructive for zeolite. The powder X-ray diffraction data confirmed that the crystallinity of the zeolite was maintained. The resulting materials were purified by Soxhlet extractor. The zeolite-included metalloporphyrins were identified for studies using UV-Vis, FTIR and EPR Spectroscopy, CA (chemical analysis), AAS (atomic absorption spectroscopy), TG/DSC, XRD, SEM and (13)C-NMR techniques. The catalytic activity of these products was examined and the catalyst showed to be a promising catalytic system to aliphatic hydrocarbon oxidation reactions. (C) 2000 Elsevier Science B.V. All rights reserved.168326127

A deletion in the N gene may cause diagnostic escape in SARS-CoV-2 samples

Five SARS-CoV-2-positive samples showed N-gene drop-out with a RT-PCR multiplex test. WGS found all samples to harbor a deletion in the same region of the N gene, which is likely to impair the efficiency of amplification. This highlights the need for a continued surveillance of viral evolution and diagnostic test performance