11 research outputs found
EXPERIMENTAL INVESTIGATION OF LOW PRESSURE TURBINE NOISE: RADIAL MODE ANALYSIS FOR SWIRLING FLOWS
L'Epitome Divinarum Institutionum di Lattanzio: proposte di analisi e traduzione.
Circa dieci anni dopo la composizione delle Divine Istituzioni, Lattanzio decide di offrirne ai suoi lettori un riassunto,in cui essi potessero ritrovare, raccolti in un unico libro ed esposti con maggiore linearità, da una parte i principali argomenti contro la religione e la filosofia pagana, dall'altra i capisaldi del cristianesimo. Sebbene si tratti di un'epitome, quindi di un testo la cui autonomia sembrerebbe apparentemente limitata, essa, in realtà costituisce quasi una seconda edizione abbreviata delle Divine Istituzioni, perché Lattanzio non si limita a riassumere pedissequamente, ma effettua soppressioni, modifiche, addirittura aggiunte, che rivelano un lavoro di rielaborazione, approfondimento e ripensamento su alcune tematiche importanti. Scopo della prima parte del presente lavoro è offrire un'immagine il più completa possibile di quest'opera, soffermandoci su ciò che la differenzia dalle Divine Istituzioni ed indagando sulle ragioni che potrebbero aver prodotto alcune scelte nella sua composizione. La seconda parte, invece, offrirà la prima traduzione in lingua italiana dell'Epitome, basata sul testo stabilito da Heck e Wlosok nella più recente edizione critica dell'opera
A Frequency-Domain Linearized Euler Model for Turbomachinery Noise Radiation Through Engine Exhaust
A numerical model for the exhaust noise radiation problem is presented. In the model, it is assumed that an incoming wave is propagating through the exhaust nozzle, or the fan duct, and radiating outside. The near-field propagation is based on the solution of the linearized Euler equations in the frequency domain: for each wave number, a linearized Euler problem is solved using a finite element method on unstructured grids for arbitrarily shaped axisymmetric geometries. The frequency-domain approach enables the suppression of the Kelvin-Helmholtz instability waves. Moreover, each single calculation, limited to a single frequency, is well suited to the exhaust noise radiation problem in which the incoming wave can be treated as a superposition of elementary duct modes. To reduce the memory requirements, a continuous Galerkin formulation with linear triangular and quadrangular elements is employed and the global matrix inversion is performed with a direct solver based on a parallel memory distributed multifrontal algorithm for sparse matrices. The acoustic near field is then radiated in the far field using the formulation of Ffowcs Williams and Hawkings. Numerical calculations for a validation test case, the Munt problem, and two turbomachinery configurations are compared with analytical solutions and experimental dat
Regulation of Type II Collagen Synthesis during Osteoarthritis by Prolyl-4-Hydroxylases : Possible Influence of Low Oxygen Levels
Osteoarthritic (OA) chondrocytes are metabolically active, displaying increased synthesis of type II collagen. Here, we show by immunohistochemistry and polymerase chain reaction that in comparison with healthy cartilage, OA articular chondrocytes exhibit increased in vivo synthesis of collagen prolyl-4-hydroxylase type II, a pivotal enzyme in collagen triple helix formation. Exposure of primary human articular chondrocytes to 1% oxygen enhanced accumulation of native type II collagen and stabilized hypoxia-inducible factor-1α (HIF-1α). This effect was abolished by addition of the HIF-1 inhibitor 2-methoxyestradiol. Real-time polymerase chain reaction analyses of mRNAs from these cultures revealed increased transcript levels of both α-subunits of prolyl-4-hydroxylase (P4HA1, ∼2-fold; P4HA2, ∼2.3-fold) and of classical HIF-1 target genes (glucosetransporter-1, ∼2.1-fold; phosphoglyceratekinase-1, ∼2.2-fold). Treatment of hypoxic chondrocytes with 2-methoxyestradiol reduced transcriptional activity of HIF-1 and synthesis of α(II), and to a lesser extent α(I), subunits of collagen prolyl-4-hydroxylases. mRNA levels of type II collagen (Col2A1) and the β-subunit (P4HB) of prolyl-4-hydroxylase, however, displayed only modest changes at 1% oxygen. From these results and our in vivo data, we inferred that besides increased Col2A1 mRNA expression by OA chondrocytes, accelerated posttranslational modification processes might contribute to the increased synthesis and accumula-tion of type II collagen during OA and experimen-tal hypoxia
Il sistema agro-alimentare dell’Emilia-Romagna, Rapporto 2014
Il Rapporto 2014 sul Sistema Agroalimentare dell'Emilia-Romagna rappresenta un importante contributo alla conoscenza di un settore fondamentale dell'economia regionale, un utile strumento per gli operatori e una guida per le politiche degli enti locali. Il Rapporto si apre con due capitoli che descrivono da un lato, lo scenario internazionale e, dall'altro le politiche comunitarie e nazionali, per il settore agroalimentare, che modificano lo scenario nel quale gli operatori saranno chiamati a muoversi dal 2014 al 2020. I principali cambiamenti congiunturali del sistema agroalimentare regionale occupano la parte central del Rapporto, con Quattro capitol dedicati all'agricoltura. Successivamente vengono affrontati gli altri aspetti rilevanti del sistema agro-alimentare regionale partendo dall'industria alimentare, con le dinamiche congiunturali e alcuni approfondimenti strutturali dell'occupazione
Intramembranous Bone Healing Process Subsequent to Tooth Extraction in Mice: Micro-Computed Tomography, Histomorphometric and Molecular Characterization
<div><p>Bone tissue has a significant potential for healing, which involves a significant the interplay between bone and immune cells. While fracture healing represents a useful model to investigate endochondral bone healing, intramembranous bone healing models are yet to be developed and characterized. In this study, a micro-computed tomography, histomorphometric and molecular (RealTimePCRarray) characterization of post tooth-extraction alveolar bone healing was performed on C57Bl/6 WT mice. After the initial clot dominance (0h), the development of a provisional immature granulation tissue is evident (7d), characterized by marked cell proliferation, angiogenesis and inflammatory cells infiltration; associated with peaks of growth factors (BMP-2-4-7,TGFβ1,VEGFa), cytokines (TNFα, IL-10), chemokines & receptors (CXCL12, CCL25, CCR5, CXCR4), matrix (Col1a1-2, ITGA4, VTN, MMP1a) and MSCs (CD105, CD106, OCT4, NANOG, CD34, CD146) markers expression. Granulation tissue is sequentially replaced by more mature connective tissue (14d), characterized by inflammatory infiltrate reduction along the increased bone formation, marked expression of matrix remodeling enzymes (MMP-2-9), bone formation/maturation (RUNX2, ALP, DMP1, PHEX, SOST) markers, and chemokines & receptors associated with healing (CCL2, CCL17, CCR2). No evidences of cartilage cells or tissue were observed, strengthening the intramembranous nature of bone healing. Bone microarchitecture analysis supports the evolving healing, with total tissue and bone volumes as trabecular number and thickness showing a progressive increase over time. The extraction socket healing process is considered complete (21d) when the dental socket is filled by trabeculae bone with well-defined medullary canals; it being the expression of mature bone markers prevalent at this period. Our data confirms the intramembranous bone healing nature of the model used, revealing parallels between the gene expression profile and the histomorphometric events and the potential participation of MCSs and immune cells in the healing process, supporting the forthcoming application of the model for the better understanding of the bone healing process.</p></div
Intramembranous Bone Healing Process Subsequent to Tooth Extraction in Mice: Micro-Computed Tomography, Histomorphometric and Molecular Characterization
Risk of COVID-19 after natural infection or vaccinationResearch in context
Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health