Weighted Multiplex Networks

One of the most important challenges in network science is to quantify the information encoded in complex network structures. Disentangling randomness from organizational principles is even more demanding when networks have a multiplex nature. Multiplex networks are multilayer systems of $N$ nodes that can be linked in multiple interacting and co-evolving layers. In these networks, relevant information might not be captured if the single layers were analyzed separately. Here we demonstrate that such partial analysis of layers fails to capture significant correlations between weights and topology of complex multiplex networks. To this end, we study two weighted multiplex co-authorship and citation networks involving the authors included in the American Physical Society. We show that in these networks weights are strongly correlated with multiplex structure, and provide empirical evidence in favor of the advantage of studying weighted measures of multiplex networks, such as multistrength and the inverse multiparticipation ratio. Finally, we introduce a theoretical framework based on the entropy of multiplex ensembles to quantify the information stored in multiplex networks that would remain undetected if the single layers were analyzed in isolation.Comment: (22 pages, 10 figures

Crafting positive/negative patterns and nanopillars of polymer brushes by photocatalytic lithography

We demonstrate a convenient and versatile approach based on the photocatalytic lithography to obtain micro- and nanostructures of polymer brushes. Micro-patterns of polymer brushes are obtained through two ways: by the selective photocatalytic degradation of an initiator, self-assembled on the surface (\u201cpositive\u201d pattern), or by a \u201cnegative\u201d pattern obtained, first, degrading an alkylsiloxane monolayer and, then, refilling it with the initiator. In both cases, the patterned initiator monolayer is eventually amplified into polymer brushes with a controlled radical polymerization protocol (ARGET ATRP). The approach described here mimics the conventional photolithography but is free from the disadvantages associated to this technique (i.e. highly energetic light sources, polymeric resists and on purpose-made photomasks). Moreover, the ability to generate nanometer-sized pillars of polymer brushes using remote photocatalysis coupled with nanosphere lithography is demonstrated. Highly monodisperse silica particles with spherical shape (diameter 3c600\ua0nm) are assembled on the surface to be patterned and used as a mask for remote photocatalysis. Our results confirm the great potentialities of TiO2-photocatalytic lithography for patterning of polymer brushes

The rise and fall of countries in the global value chains

Countries become global leaders by controlling international and domestic transactions connecting geographically dispersed production stages. We model global trade as a multi-layer network and study its power structure by investigating the tendency of eigenvector centrality to concentrate on a small fraction of countries, a phenomenon called localization transition. We show that the market underwent a significant drop in power concentration precisely in 2007 just before the global financial crisis. That year marked an inflection point at which new winners and losers emerged and a remarkable reversal of leading role took place between the two major economies, the US and China. We uncover the hierarchical structure of global trade and the contribution of individual industries to variations in countries’ economic dominance. We also examine the crucial role that domestic trade played in leading China to overtake the US as the world’s dominant trading nation. There is an important lesson that countries can draw on how to turn early signals of upcoming downturns into opportunities for growth. Our study shows that, despite the hardships they inflict, shocks to the economy can also be seen as strategic windows countries can seize to become leading nations and leapfrog other economies in a changing geopolitical landscape

Preparation of a sepia melanin and poly(ethylene-alt-maleic anhydride) hybrid material as an adsorbent for water purification

Meeting the increasing demand of clean water requires the development of novel efficient adsorbent materials for the removal of organic pollutants. In this context the use of natural, renewable sources is of special relevance and sepia melanin, thanks to its ability to bind a variety of organic and inorganic species, has already attracted interest for water purification. Here we describe the synthesis of a material obtained by the combination of sepia melanin and poly(ethylene-alt-maleic anhydride) (P(E-alt-MA)). Compared to sepia melanin, the resulting hybrid displays a high and fast adsorption efficiency towards methylene blue (a common industrial dye) for a wide pH range (from pH 2 to 12) and under high ionic strength conditions. It is easily recovered after use and can be reused up to three times. Given the wide availability of sepia melanin and P(E-alt-MA), the synthesis of our hybrid is simple and affordable, making it suitable for industrial water purification purposes

Patterning of polymer brushes made easy using titanium dioxide: direct and remote photocatalytic lithography

Photocatalytic lithography is proved for the realization of micropatterned polymer brushes. Initiator-functionalized titanium dioxide or silicon surfaces are respectively exposed directly to near-UV light through a photomask (direct approach) or through a transparent photoactive TiO2 film (remote approach). Initiator patterns are then amplified as polymer brushes with SI-ATRP. Features down to 10 \u3bcm could be obtained using simple equipment. The process is intrinsically parallel, has high throughput and scalable to wafer size, making it powerful for microfabrication purposes

Convenient Preparation of Graphene Oxide from Expandable Graphite and Its Characterization by Positron Annihilation Lifetime Spectroscopy

Graphene oxide (GO) is conveniently prepared from expandable graphite using a simplified Hummers\u2019 method. The product is thoroughly characterized by usual techniques (UV-vis, Fourier-transform infrared (FTIR) and Raman spectroscopies, zeta potential, electron microscopy, X-ray diffraction, nitrogen adsorption) to confirm the success of synthesis. Positron annihilation lifetime spectroscopy (PALS) is then used to extract information on the microenvironment in between the layers of graphene oxid

ON/OFF switching of silicon wafer electrochemistry by pH-responsive polymer brushes

pH-Switchable electrochemical properties are demonstrated for the first time for native oxide-coated silicon wafer electrodes. Ultrathin and ultrathick pH-responsive poly(methacrylic acid) (PMAA) brushes, obtained by surface-initiated atom transfer radical polymerization, were used to achieve redox gating. PMAA brushes are reversibly switched between their protonated and deprotonated states by alternating acidic and basic pH, which corresponds to a swelling/collapsing behavior. As a result, the electrochemical properties of the PMAA brush-modified silicon electrode are switched "ON" and "OFF" simply by changing pH. The electrochemical properties of the modified electrode were examined by means of cyclic voltammetry and electrochemical impedance spectroscopy both in the absence and presence of ruthenium(iii) hexamine, a well-known cationic redox probe

An archetype-based solution for the interoperability of computerised guidelines and electronic health records

Clinical guidelines contain recommendations based on the best empirical evidence available at the moment. There is a wide con- sensus about the benefits of guidelines and about the fact that they should be deployed through clinical information systems, making them available during consultation time. However, one of the main obstacles to this integration is still the interaction with the electronic health record. In this paper we present an archetype-based approach to solve the inter- operability problems of guideline systems, as well as to enable guideline sharing. We also describe the knowledge requirements for the develop- ment of archetype-enabled guideline systems, and then focus on the de- velopment of appropriate guideline archetypes and on the connection of these archetypes to the target electronic health record

Transsphenoidal surgery for pituitary adenomas: early results from a single center

To evaluate early results of transsphenoidal surgery for pituitary adenomas

Self-cleaning properties in engineered sensors for dopamine electroanalytical detection

Fouling and passivation are the major drawbacks for a wide applicability of electroanalytical sensors based on nanomaterials, especially in biomedical and environmental fields. The production of highly engineered devices, designed ad hoc for specific applications, is the key factor in the direction of overcoming the problem and accessing effective sensors. Here, the fine-tuning of the system, composed of a highly ordered distribution of silver nanoparticles between a bottom silica and a top titania layer, confers multifunctional properties to the device for a biomedical complex challenge: dopamine detection. The crucial importance of each component towards a robust and efficient electroanalytical system is studied. The total recovery of the electrode performance after a simple UV-A cleaning step (self-cleaning), due to the photoactive interface and the aging resistance, is deeply investigated