A nonlinear rotational, quasi-2DH, numerical model for spilling wave propagation

The propagation of spilling waves interacting with complex bathymetries was studied by means of a new two-dimensional weakly dispersive, fully nonlinear Boussinesq-type of model. In particular, the governing equations were derived assuming the flow as rotational, and the effects of vorticity due to breaking were included through the surface roller concept, which was defined and implemented on the basis of a new algorithm developed for the purpose. The propagation of vorticity, due to wave breaking, is estimated under the assumption that the effect of convection is leading order with respect to the effect of vorticity-stretching and that the breaking phenomenon does not show high curvature on the horizontal plane. In particular, the dynamic problem is decoupled in a lateral direction considering a series of separated sections in which vorticity is solved. In this way it is possible to obtain rotational information along the domain to a reasonable computational cost. The numerical model was validated in a simple one-dimensional case and then applied to the study of breaking-generated vorticity due to wave motion over a submerged shoal

Metal Nanoparticles Deposited on Porous Silicon Templates as Novel Substrates for SERS

In this paper, results on preparation of stable and uniform SERS solid substrates using macroporous silicon (pSi) with deposited silver and gold are presented. Macroporous silicon is produced by anodisation of p-type silicon in hydrofluoric acid. The as prepared pSi is then used as a template for Ag and Au depositions. The noble metals were deposited in three different ways: by immersion in silver nitrate solution, by drop-casting silver colloidal solution and by pulsed laser ablation (PLA). Substrates obtained by different deposition processes were evaluated for SERS efficiency using methylene blue (MB) and rhodamine 6G (R6G) at 514.5, 633 and 785 nm. Using 514.5 nm excitation and R6G the limits of detection (LOD) for macroporous Si samples with noble metal nanostructures obtained by immersion of pSi sample in silver nitrate solution and by applying silver colloidal solution to pSi template were 10–9 M and 10–8 M respectively. Using 633 nm laser and MB the most noticeable SERS activity gave pSi samples ablated with 30000 and 45000 laser pulses where the LODs of 10–10 M were obtained. The detection limit of 10–10 M was also reached for 4 mA cm–2-15 min pSi sample, silver ablated with 30000 pulses. Macroporous silicon proved to be a good base for the preparation of SERS substrates

Spectrum of sepsis, mediators, source control and management of bundles.

Sepsis is a modern medicine icon and the onset of organ dysfunction is one of the worst scenario. More than 100 distinct molecules have been proposed as useful biological markers of sepsis. TNF-alpha, IL-6, chemokines and cytokines are considered the first line factors able to drive the dynamic process of sepsis. The PIRO scheme is a new classification of different aspects, used to stage sepsis. Resuscitation bundles must be started within 6 hours of presentation (serum lactate measured; blood cultures obtained before antibiotic therapy; broad-spectrum antibiotics within 3 hours from emergency admission and 1 hour from ICU admission; in case of hypotension and/or lactate higher than 4 mmol/L deliver an initial 20 ml/kg of crystalloid or colloid solution or apply vasopressors for hypotension not responding to initial fluid resuscitation to maintain mean arterial pressure above 65 mmHg). A management bundle should be implemented within 24 hour (low-dose steroids administered for septic shock; recombinant human activated protein C; glucose control maintained at less than 8.3 mmol/L; inspiratory plateau pressures maintained at less than 30 cm H2O)

Valutazione della vulnerabilità sismica della chiesa di sant’Agostino ad Amatrice tramite analisi multitemporali

La chiesa di Sant’Agostino ad Amatrice è divenuta il simbolo dei tanti beni architettonici gravemente danneggiati dalla lunga sequenza sismica del 2016- 2017, che progressivamente l’ha portata ad un crollo quasi totale. La ricerca multidisciplinare ha avuto la finalità di interpretare il danneggiamento della chiesa, prima in forma di gravi lesioni e poi definitivamente di collasso, correlando in modo interdisciplinare un insieme di dati eterogenei. I modelli digitali derivati dai rilievi 3D realizzati seguendo i progressivi danneggiamenti, gli studi storici delle lesioni emerse in seguito ad altri importanti eventi sismici del passato, lo studio e l’analisi critica dei precedenti lavori di consolidamento, i risultati della microzonazione sismica per la definizione della risposta sismica locale dell’edificio, i risultati delle prove diagnostiche eseguite in situ sulle strutture murarie e la modellazione agli elementi finiti del comportamento dinamico dell’edificio sono discussi in forma integrata

Optical trapping of silver nanoplatelets

Optical trapping of silver nanoplatelets obtained with a simple room temperature chemical synthesis technique is reported. Trap spring constants are measured for platelets with different diameters to investigate the size-scaling behaviour. Experimental data are compared with models of optical forces based on the dipole approximation and on electromagnetic scattering within a T-matrix framework. Finally, we discuss applications of these nanoplatelets for surface-enhanced Raman spectroscopy

Functionalization of Polyhydroxyalkanoates (PHA)-Based Bioplastic with Phloretin for Active Food Packaging: Characterization of Its Mechanical, Antioxidant, and Antimicrobial Activities

: The formulation of eco-friendly biodegradable packaging has received great attention during the last decades as an alternative to traditional widespread petroleum-based food packaging. With this aim, we designed and tested the properties of polyhydroxyalkanoates (PHA)-based bioplastics functionalized with phloretin as far as antioxidant, antimicrobial, and morpho-mechanic features are concerned. Mechanical and hydrophilicity features investigations revealed a mild influence of phloretin on the novel materials as a function of the concentration utilized (5, 7.5, 10, and 20 mg) with variation in FTIR e RAMAN spectra as well as in mechanical properties. Functionalization of PHA-based polymers resulted in the acquisition of the antioxidant activity (in a dose-dependent manner) tested by DPPH, TEAC, FRAR, and chelating assays, and in a decrease in the growth of food-borne pathogens (Listeria monocytogenes ATCC 13932). Finally, apple samples were packed in the functionalized PHA films for 24, 48, and 72 h, observing remarkable effects on the stabilization of apple samples. The results open the possibility to utilize phloretin as a functionalizing agent for bioplastic formulation, especially in relation to food packaging

Rilievo 3D e monitoraggio dinamico della Torre degli Smeducci e del campanile del Duomo vecchio a San Severino Marche

Le attività della task force del Politecnico nell’Italia Centrale, nelle fasi post sisma del 2016, sono state indirizzate non solo alle aree epicentrali, ma si sono estese anche ad aree del cratere sismico che hanno subito danneggiamenti meno importanti. In queste aree le attività sono state rivolte alla analisi di beni monumentali ad alta vulnerabilità che hanno subito danneggiamenti limitati. In questo contesto si inquadrano le indagini condotte su due torri storiche di San Severino Marche, la Torre del Duomo Vecchio e la Torre degli Smeducci. Tali attività fanno parte di un piano di cooperazione strategica tra il Comune di San Severino Marche, il Politecnico di Torino e di Nagoya City University (Giappone)

Roadmap for Optical Tweezers 2023

Optical tweezers are tools made of light that enable contactless pushing, trapping, and manipulation of objects ranging from atoms to space light sails. Since the pioneering work by Arthur Ashkin in the 1970s, optical tweezers have evolved into sophisticated instruments and have been employed in a broad range of applications in life sciences, physics, and engineering. These include accurate force and torque measurement at the femtonewton level, microrheology of complex fluids, single micro- and nanoparticle spectroscopy, single-cell analysis, and statistical-physics experiments. This roadmap provides insights into current investigations involving optical forces and optical tweezers from their theoretical foundations to designs and setups. It also offers perspectives for applications to a wide range of research fields, from biophysics to space exploration