Transient growth in the flow past a three-dimensional smooth roughness element

This work provides a global optimization analysis, looking for perturbations inducing the largest energy growth at a finite time in a boundary-layer flow in the presence of smooth three-dimensional roughness elements. Amplification mechanisms are described which can bypass the asymptotical growth of Tollmien–Schlichting waves. Smooth axisymmetric roughness elements of different height have been studied, at different Reynolds numbers. The results show that even very small roughness elements, inducing only a weak deformation of the base flow, can localize the optimal disturbance characterizing the Blasius boundary-layer flow. Moreover, for large enough bump heights and Reynolds numbers, a strong amplification mechanism has been recovered, inducing an increase of several orders of magnitude of the energy gain with respect to the Blasius case. In particular, the highest value of the energy gain is obtained for an initial varicose perturbation, differently to what found for a streaky parallel flow. Optimal varicose perturbations grow very rapidly by transporting the strong wall-normal shear of the base flow, which is localized in the wake of the bump. Such optimal disturbances are found to lead to transition for initial energies and amplitudes considerably smaller than sinuous optimal ones, inducing hairpin vortices downstream of the roughness element

Polimorfismi metabolici: applicazioni nello studio della patologia multifattoriale e nel monitoraggio biologico dell’esposizione a xenobiotici

I polimorfismi metabolici, ossia le variabili espressioni fenotipiche degli enzimi coinvolti nella biotrasformazione degli xenobiotici, dovuti a differenze di sequenza genetica presenti nelle popolazioni con frequenze pari ad almeno l’1%, possono spiegare parte della variabilità interindividuale nella risposta all’esposizione a fattori di rischio. Vengono riportati i risultati di due studi epidemiologici, in cui i polimorfismi metabolici sono stati valutati come modificatori del rischio nello sviluppo della malattia di Parkinson (MP) e come modificatori degli indicatori biologici di esposizione e di effetto nella stima del rischio derivante dall’esposizione professionale a basse dosi di benzene. Il primo studio, retrospettivo caso-controllo, di dimensioni Europee, ha evidenziato che i polimorfismi delle glutatione S-transferasi M1-1 (GSTM1) e P1-1 (GSTP1) e dell’acetil N-transferasi 2 (NAT-2) modulano significativamente il ruolo “neuroprotettivo” svolto dal fumo di tabacco nei confronti della MP. Il secondo studio, trasversale su un ampio gruppo di lavoratori professionalmente esposti alle basse concentrazioni di benzene misurabili in ambiente urbano, e costituito da taxisti, vigili urbani e benzinai, dimostra la modulazione delle concentrazioni urinarie dell’indicatore di esposizione acido S-fenilmercapturico (SPMA) da parte dei polimorfismi metabolici influenzanti le attività glutatione S-transferasiche M1-1, T1-1 e A1-1 (GSTM1, GSTT1, GSTA1). E’ dimostrata inoltre la modulazione del danno ossidativo indotto dall’esposizione a benzene, valutato tramite misura degli indicatori urinari di danno ossidativo alla guanina, da parte del polimorfismo metabolico dell’enzima NAD(P)H:chinone ossidoreduttasi 1 (NQO1)

Urinary exosomal shuttle RNA: Promising cancer diagnosis biomarkers of lower urinary tract.

Background: Prostate and bladder cancers continue to be the first and fourth most common cancers in men worldwide; thus there is an urgent need for more accurate biomarkers that can detect these types of cancer in a non-invasive way. Liquid biopsy is a new non-invasive tool for diagnosis and with a virtually unlimited supply urine is even more attractive resource since urinary exosomes have been discovered to contain RNAs that are hallmarks of cancer. It is challenging to assay those secreting lower amounts of molecules. Methods: This review, based on articles identified through a PubMed/MEDLINE search, comprehensively summarizes state of the art approaches used in the discovery and validation of exosomal RNA biomarkers purified from the urine for lower urinary tract cancer. Results: The combination of PCA3 and ERG has shown a relatively good improvement in diagnostic performance; examples of other potential biomarkers and the methods utilized in their discovery are also discussed in this review. Conclusions: Of these last markers, to date there are still few data to implement these for routine diagnosis

Novel Penicillin-Type Analogues Bearing a Variable Substituted 2-Azetidinone Ring at Position 6: Synthesis and Biological Evaluation

The synthesis and the biological activity of novel semi-synthetic β-lactam compounds containing an azetidinone moiety joined to the amino-nitrogen of the (+)-6-aminopenicillanic acid (6-APA) as new antibacterial agents is reported. The synthesized compounds were screened for their in vitro antimicrobial activity against a panel of Gram positive and Gram negative pathogens and environmental bacteria. Tested compounds displayed good antimicrobial activity against all tested Gram positive bacteria and for Staphylococcus aureus and Staphylococcus epidermidis antimicrobial activity resulted higher than that of the reference antibiotic. Additionally, in vitro cytotoxic screening was also carried out indicating that the compounds do not cause a cell vitality reduction effective at concentration next to and above those shown to be antimicrobial

A demand model with departure time choice for within-day dynamic traffic assignment

A within-clay dynamic demand model is formulated, embodying, in addition to the classic generation, distribution and modal split stages, an actual demand model taking into account departure time choice. The work focuses on this last stage, represented through an extension of the discrete choice framework to a continuous choice set. The dynamic multimodal supply and equilibrium model based on implicit path enumeration, which have been developed in previous work are outlined here, to define within-day dynamic elastic demand stochastic multimodal equilibrium as a fixed point problem on users flows and transit line frequencies. A MSA algorithm capable, in the case of Logit route choice models, of supplying equilibrium flows and frequencies on real dimension networks, is presented, as well as the specific procedures implementing the departure time choice and actual demand models. Finally, the results obtained on a test network are presented and conclusions are drawn. (c) 2005 Elsevier B.V. All rights reserved

Serverless Scheduling Policies based on Cost Analysis

Current proprietary and open-source serverless platforms follow opinionated, hardcoded scheduling policies to deploy the functions to be executed over the available workers. Such policies may decrease the performance and the security of the application due to locality issues (e.g., functions executed by workers far from the databases to be accessed). These limitations are partially overcome by the adoption of APP, a new platform-agnostic declarative language that allows serverless platforms to support multiple scheduling logics. Defining the "right" scheduling policy in APP is far from being a trivial task since it often requires rounds of refinement involving knowledge of the underlying infrastructure, guesswork, and empirical testing. In this paper, we start investigating how information derived from static analysis could be incorporated into APP scheduling function policies to help users select the best-performing workers at function allocation. We substantiate our proposal by presenting a pipeline able to extract cost equations from functions' code, synthesising cost expressions through the usage of off-the-shelf solvers, and extending APP allocation policies to consider this information.Comment: In Proceedings TiCSA 2023, arXiv:2310.1872