Nonsmooth viscosity solutions of elementary symmetric functions of the complex Hessian

In this paper we prove the existence of nonsmooth viscosity solutions for Dirichlet problems involving elementary symmetric functions of the eigenvalues of the complex Hessian

Palais-Smale sequences for the fractional CR Yamabe functional and multiplicity results

In this paper we consider the functional whose critical points are solutions of the fractional CR Yamabe type equation on the sphere. We firstly study the behavior of the Palais-Smale sequences characterizing the bubbling phenomena and therefore we prove a multiplicity type result by showing the existence of infinitely many solutions to the related equation.Comment: 30 page

Design and development of a microfluidic biochip for chemical and physical cell stimulation

Biomolecular concentration gradients play relevant roles in many biological phenomena including development, inflammation, wound healing, and cancer growth and spreading. In order to better investigate and elucidate these aspects, several in vitro systems have been defined for exposing cells to chemical gradients. In combination with in vivo studies, these methods have revealed gradient signalling to be an intricate, highly-regulated process, in which the ultimate cellular response is determined by the concentration, and spatiotemporal characteristics of the gradients to which the cells are exposed. A complete understanding of gradient on cellular behaviour is still on going and more technological platforms are required to increase the knowledge of many cellular mechanisms. Thus it is a big technological challenge the realization of systems that makes the in vitro environment more similar to the in vivo one, including spatially and temporally organized signals supplemented with sensors for monitoring cellular parameters.This work is focused on the realization of a microfluidic chip for controlled cell culture, integrating a gradient generator and a micropatterned substrate. Exploiting the advantages of soft lithographic techniques, a polymeric structure in polydimethylsiloxane (PDMS) is conceived with two orthogonal sets of fluidic channels and active components, such as switching valves. The system is designed to be applied on a substrate, previously patterned by non-conventional micro contact printing of adhesion proteins. Finally, the developed system guarantees the production of a complex user-defined gradient, with tailored spatial and temporal profiles; secondly, it allows immobilizing and observing a selected small population of adherent cells. The remainder of this thesis is organised as follows. Chapter 1 presents a brief description of microfluidic gradient generators, highlighting the limits of the published architectures. In Chapter 2 a novel microfluidic gradient generator is proposed. This system is designed to allow generating multiple concentration gradients. The microfluidic network is combined with a glass substrate which presents cell-adhesive and cell-repellent areas. Materials and methods for the fabrication of the chip and for the substrate micropatterning are presented in Chapter 3. Specifically, Multilayer Soft Lithography (MLSL), used for the microfluidic chip fabrication, and micro-contact printing (micro-CP), required for the substrate micropatterning are described in detail. In Chapter 4 all the specific fabrication protocols and an extensive experimental characterization and validation of the system are reported and discussed. In particular, three major results are presented: i) demonstration of complex gradient generation, ii) micro-patterning of fibronectin/PLL-g-PEG on glass substrates, iii) immobilization on the microfabricated systems. Chapter 5 outlines obtained results and contributions and suggests directions for the future work

From seismic hazards to resilient cities. The contribution of engineering geology

Different types of natural hazard affect the surface of the Earth, exposing human communities to high-risk conditions. This fact makes it imperative to identify strategies for preventing, responding to, managing, and recovering from natural disasters. It is within this framework that the concept of “resilience” has arisen. Achieving a resilient condition is the only way to mitigate the impact of and the losses due to natural disasters, as well as to protect the health and well-being of communities. The paper discusses the contribution that engineering geology can provide to increasing the structural and social resilience of communities to the impact of earthquakes. Creating awareness of engineering geology applications in society and among public institutions can enhance social resilience, while promoting the understanding of natural processes and their interactions with man-made structures and the environment can improve the structural component of resilience. The paper describes the role of engineering geology as a new player in strengthening community resilience, suggesting the need for a multidisciplinary approach to achieving a resilient condition

Expression of membrane-associated proteins within single emulsion cell facsimiles

MreB is a structural membrane-associated protein which is one of the key components of the bacterial cytoskeleton. Although it plays an important role in shape maintenance of rod-like bacteria, the understanding of its mechanism of action is still not fully understood. This study shows how segmented flow and microdroplet technology can be used as a new tool for biological in vitro investigation of this protein. In this paper, we demonstrate cell-free expression in a single emulsion system to express red fluorescence protein (RFP) and MreB linked RFP (MreB–RFP). We follow the aggregation and localisation of the fusion protein MreB–RFP in this artificial cell-like environment. The expression of MreB–RFP in single emulsion droplets leads to the formation of micrometer-scale protein patches distributed at the water/oil interface

Estimation of genetic diversity over time in an in-situ marker assisted conservation scheme of local chicken breeds.

The aim of this research was to study the genetic variability of two local chicken breeds (Ermellinata di Rovigo and Robusta Maculata) involved in a conservation programme, over a period of three years. Samples were collected in 2002 and in 2005 and analysed using 15 microsatellite markers. Obtained results evidenced that Robusta Maculata was genetically less variable than Ermellinata di Rovigo even after three years of conservation activities. During the studied period the observed heterozigosity was maintained and the excess of homozygous animals found in both breeds in 2002 was strongly reduced in 2005. These findings suggested that the conservation activities helped to overcome the probable presence of population substructures and to limit inbreeding. Moreover, this study evidenced the usefulness of microsatellite markers to monitor genetic diversity in conservation programmes for animal breeds

Singular CR structures of constant Webster curvature and applications

We consider the sphere (Formula presented.) equipped with its standard contact form. In this paper, we construct explicit contact forms on (Formula presented.), which are conformal to the standard one and whose related Webster metrics have constant Webster curvature; in particular, it is positive if (Formula presented.). As main applications, we provide two perturbative results. In the first one, we prove the existence of infinitely many contact forms on (Formula presented.) conformal to the standard one and having constant Webster curvature, where (Formula presented.) is a small perturbation of (Formula presented.). In the second application, we show that there exist infinitely many bifurcating branches of periodic solutions to the CR Yamabe problem on (Formula presented.) having constant Webster curvature. © 2023 The Authors. Mathematische Nachrichten published by Wiley-VCH GmbH