Electro-osmotic flow in coated nanocapillaries: a theoretical investigation

Motivated by recent experiments, we present a theoretical investigation of how the electro-osmotic flow occurring in a capillary is modified when its charged surfaces are coated by charged polymers. The theoretical treatment is based on a three dimensional model consisting of a ternary fluid-mixture, representing the solvent and two species for the ions, confined between two parallel charged plates decorated by a fixed array of scatterers representing the polymer coating. The electro-osmotic flow, generated by a constant electric field applied in a direction parallel to the plates, is studied numerically by means of Lattice Boltzmann simulations. In order to gain further understanding we performed a simple theoretical analysis by extending the Stokes-Smoluchowski equation to take into account the porosity induced by the polymers in the region adjacent the walls. We discuss the nature of the velocity profiles by focusing on the competing effects of the polymer charges and the frictional forces they exert. We show evidence of the flow reduction and of the flow inversion phenomenon when the polymer charge is opposite to the surface charge. By using the density of polymers and the surface charge as control variables, we propose a phase diagram that discriminates the direct and the reversed flow regimes and determine its dependence on the ionic concentration.Comment: 15 pages, 6 figures in Physical Chemistry Chemical Physics, 201

Tumori germinali del testicolo in giovani pazienti: aspetti chirurgici e risultati a distanza

I tumori germinali del testicolo (GCT) sono affezioni rare, essi rappresentano circa l’1% di tutti i tumori nel sesso maschile. I GCT rivestono una rilevanza clinica essendo la più comune neoplasia diagnosticata nella fascia di età compresa tra 15-34 anni e costituendo il 95% dei tumori maligni del testicolo. L’incidenza del GCT è più che raddoppiata negli ultimi 40 anni. L’alta sensibilità dei GCT alla chemioterapia a base di platino, insieme alla radioterapia e alla chirurgia, ha permesso di raggiungere una sopravvivenza a lungo termine di oltre il 99 % negli stadi iniziali e rispettivamente del 90%, 80% e del 50% negli stadi avanzati con “good”, “intermediate”, “poor” prognosi, secondo i criteri dell’International Germ Cell Cancer Collaborative Group (IGCCCG). Per tale motivo i GCT vengono considerati un modello di neoplasia solida “curabile”. Importante per la prognosi è l’ottimizzazione della cura con un’integrazione razionale delle varie possibilità terapeutiche in base allo stadio della malattia. Lo scopo è quello di evitare sia un overtreatment nei pazienti a basso rischio con le conseguenti complicanze trattamento correlate, sia, al contrario, rischiare di non attuare una terapia ottimale nei pazienti con malattia avanzata o refrattaria al trattamento. I GCT sono suddivisi in due gruppi principali: i non seminomi (NSGCT) e i seminomi (SGCT); in alcuni casi i due istotipi possono coesistere nella solita neoplasia (GCT combinati). IL GCT ha una caratteristica distribuzione per età, con un primo picco nell’infanzia e con un secondo picco ben più ampio che inizia subito dopo la pubertà. Nella prima infanzia i GCT sono quasi esclusivamente NSGCT (soprattutto Yolk sac tumors). Fra gli adolescenti e i giovani adulti predominano i NSGCT e i GCT combinati mentre i SGCT predominano sopra i 25 anni. Nella tesi sono stati revisionati retrospettivamente i dati clinici e le modalità di trattamento di 155 pazienti operati per tumori a cellule germinali del testicolo. I pazienti sono stati suddivisi in due gruppi di età 25 anni. Di ciascun gruppo sono stati analizzati i sintomi di esordio, i markers tumorali sierologici, la stadiazione clinica (secondo i criteri TNM dell’UICC-AJCC), la tattica chirurgica (comprendendo la linfoadenectomia retro peritoneale), ed il follow-up (espresso secondo la sopravvivenza libera da malattia e la sopravvivenza globale). I due gruppi sono stati correlati mediante una analisi statistica al fine di ricercare una significatività tra i vari parametri

Predicted properties of Galactic and Magellanic Classical Cepheids in the SDSS filters

We present the first extensive and detailed theoretical scenario for the interpretation of Cepheid properties observed in the SDSS filters. Three sets of nonlinear convective pulsation models, corresponding to the chemical compositions of Cepheids in the Milky Way, the Large Magellanic Cloud and the Small Magellanic Cloud respectively, are transformed into the SDSS bands by relying on updated model atmospheres. The resulting observables, namely the instability strip boundaries and the light curves, as well as the Period-Luminosity, the Wesenheit and the Period-Luminosity-Colour relations, are discussed as a function of the metal content, for both the fundamental and the first overtone mode. The fundamental PL relations are found to deviate from linear relations when computed over the whole observed Cepheid period range, especially at the shorter wavelenghts, confirming previous findings in the Johnson-Cousins bands. The obtained slopes are found to be mildly steeper than the ones of the semiempirical and the empirical relations available in the literature and covering roughly the same period range, with the discrepancy ranging from about 13% in u-band to about 3% in z.Comment: Accepted for publication in MNRA

a 4m approach for a comprehensive analysis and improvement of manual assembly lines

Abstract Design for Assembly (DfA) is a well-known technique that supports in the reduction of manufacturing costs. Traditional DfA methods are generally focused on the product design lacking of a holistic view. The proposed 4 M approach takes into account all the most important aspects involved in the manual assembly: Method, Machine, Man and Material. The final goal is to provide a means for the concurrent improvement of the product design, the workstation ergonomics, and the assembly tasks. Results obtained with the electric spindle motor case study confirmed the usefulness of the approach in optimizing the manual assembly

A critical review of symbiosis approaches in the context of Industry 4.0☆

Abstract The implementation of symbiosis approaches is recognized as an effective industrial strategy towards the optimization of resource exploitation and the improvement of collaboration in the context of Industry 4.0. An industrial system can be considered as a complex environment in which material, energy, machine, and human resources should cooperate towards the improvement of efficiency and the creation of value. According to this vision, the paper presents a detailed literature review about the existing symbiosis approaches: (i) industrial symbiosis models, which mainly aim at the sharing of resources among different companies, and (ii) human symbiosis, which focuses on how to effectively strengthen the synergy among humans and machines. Strengths, weaknesses and correlations among the most common symbiosis approaches are analysed and classified. Finally, the existing symbiosis models are related with the pillars of the Industry 4.0 paradigm, in order to understand what should be the future directions of research in the context of collaborative manufacturing

Teaching eco-design by using LCA analysis of company's product portfolio: the case study of an Italian manufacturing firm

Abstract Eco-design is a design paradigm aiming to the development of sustainable products. Life Cycle Assessment (LCA) is considered an eco-design tool able to assess the product environmental performances through a life cycle perspective. However, LCA shows some limitations in industry's daily practice and cannot be considered a standard for implementing eco-design. The paper aims to describe the implementation of a novel eco-design teaching approach involving company's employees from different technical departments. LCA analysis of company's product portfolio allowed to create a specific eco-knowledge, used to train designers and engineers on this subject for the implementation of eco-design actions during the development of new products (espresso coffee machine). Results highlighted relevant learning outcomes and significant improvements in terms of environmental sustainability of a new product design

analyzing the environmental sustainability of glass bottles reuse in an italian wine consortium

Abstract The wine production constitutes an important sector for the Italian economy. Most of the wine producers are associated in local consortiums, which include small family companies involved in the production of similar products. This study aims to investigate the implementation of circular economy opportunities in the wine production chain. In particular, the reuse of glass bottles in the Piceno wine consortium (central Italy) has been analyzed to quantify the potential environmental benefits. The standard Life Cycle Assessment (LCA) methodology has been used to compare the standard scenario (recycle of glass) against the circular scenario (cleaning and reuse of bottles within the local consortium). Results demonstrate that the reuse of glass bottles leads to relevant benefits in all the considered impact categories (ReCiPe Midpoint method). The avoided use of virgin glass offsets the additional resources (e.g. energy) consumed during the cleaning of used bottles

IL TRATTAMENTO ENDOVASCOLARE DEGLI ANEURISMI DELL'AORTA ADDOMINALE: IL RAZIONALE DELLA SCELTA DI UN CENTRO DI FORMAZIONE DEL CHIRURGO VASCOLARE

Il trattamento degli aneurismi dell’aorta addominale (AAA) è andato incontro ad un epocale cambiamento in seguito alle innovazioni endovascolari introdotte nel 1990 da Parodi. Dalla nascita dell’EndoVascular Aneurysm Repair (EVAR), l’evoluzione delle tecniche e dei materiali endovascolari ha spostato le possibili applicazioni del trattamento endoprotesico verso frontiere sempre più lontane e di conseguenza le indicazioni sono passate dai pazienti ad alto rischio ad un utilizzo massivo con centri che la utilizzano in più dell’80% dei casi. Questi veloci mutamenti hanno condotto però da un lato ad una mancanza di chiarezza nelle indicazioni al trattamento endoprotesico e dall’altro ad una riduzione degli interventi di chirurgia tradizionale. La scelta dell’U.O. di Chirurgia Vascolare dell’Azienda Ospedaliero Universitaria Pisana (AOUP), per quanto riguarda le indicazioni all’EVAR, è stata quella di riservare il trattamento endoprotesico solo ai pazienti affetti da AAA con morfologia rigorosamente conforme a quella indicata nelle Instruction For Use (IFU) dei vari device in commercio. Tale scelta è stata effettuata nell’ottica di ottenere buoni risultati nel trattamento EVAR e mantenere una percentuale maggiore di interventi tradizionali in un centro di formazione di giovani chirurghi vascolari

Enhanced dissipation for two-dimensional Hamiltonian flows

Let $H\in C^1\cap W^{2,p}$ be an autonomous, non-constant Hamiltonian on a compact $2$-dimensional manifold, generating an incompressible velocity field $b=\nabla^\perp H$. We give sharp upper bounds on the enhanced dissipation rate of $b$ in terms of the properties of the period $T(h)$ of the close orbits $\{H=h\}$. Specifically, if $0<\nu\ll 1$ is the diffusion coefficient, the enhanced dissipation rate can be at most $O(\nu^{1/3})$ in general, the bound improves when $H$ has isolated, non-degenerate elliptic point. Our result provides the better bound $O(\nu^{1/2})$ for the standard cellular flow given by $H_\mathsf{c}(x)=\sin x_1 \sin x_2$, for which we can also prove a new upper bound on its mixing mixing rate and a lower bound on its enhanced dissipation rate. The proofs are based on the use of action-angle coordinates and on the existence of a good invariant domain for the regular Lagrangian flow generated by $b$.Comment: 23 pages, 2 figure