Physical and functional characterization of PHASCL membranes

Dense semicrystalline membranes of polyhydroxyalkanoates with medium change length (PHA_SCL), polyhydroxybutyrate (PHB) and poly β (hydroxybutyrate-co-hydroxyvalerate) [P(βHB-co-XβHV)] were characterized using wide-angle X-ray (WAXS) and scanning electron microscopy. PHB membranes showed a more rugged surface than those of copolymers (0-22%HV). Properties such as swelling capacity, vapor permeability and selectivity were investigated. Swelling percentage in water-ethanol mixtures was 34% for PHB as compared to 14% for copolymers membranes. The ethanol/water selectivity (α_s) of PHB was 5.8 which shows that it is more selective than copolymers.The water vapor and ethanol vapor permeability were determined by a gravimetric technique at different temperatures by static and dynamic methods. PHB permeability was 69.5 Barrer at 30 °C and a discreet increment was observed at temperatures (30-50 °C). The difference in permeability between PHB and [P(βHB-co-X%βHV)] could be interpreted in terms of the crystallization rate, crystallite size and distribution which impact to transport properties of amorphous phase.     

Full-digital control boards for IGBT full-bridge switchingconverters

In the field of thermonuclear fusion research, the need to implement coil systems supplied to perform local controls of magnetic fluxes or to generate rotating magnetic fields has grown in the past few years. Tens of coils, each one able to produce up to tens of millitesla on a surface of hundreds of square centimeters, have to be independently fed by converters rated for powers of hundreds of kilowatts and bandwidth in the order of hundreds of hertz. The approach for the design of the converter system, described in this article, involving 22 insulated-gate bipolar transistors (IGBTs) full-bridges, was a semi-custom solution. It is based on the utilization of a well-tested and optimized industrial product for the power section, including the IGBTs driving signal board and the development of a new digital control board. This choice is also in line with the present trend in power-electronic technology that suggests using as much standardized subassemblies as possible and customizing them for different applications     

SECT: An effective coding technique for polygonal geographic data

Memory occupation of geographic data and efficiency of the selection and elaboration algorithms are challenging problems in designing a system for polygonal data processing. They arise basically from the large number of polygon vertices necessary to properly approximate territory maps. Since the number of vertices is determined by the expected resolution, data compression can only be achieved by reducing the memory occupation of each point. On the other hand, more efficient algorithms are obtained if unnecessary operations are carefully avoided: in geographic data processing this is done by precisely delimiting the territory areas to be processed. In this paper, the SECT coding technique is presented, which meets both the above requirements. Its data compression capability is proved with reference to points, lines and regions coding, having considered geographic data of different density. Furthermore, the benefits it ensures in terms of both CPU time and I/O operation savings are discussed.     

Photo-fenton and UV photo degradation of naphthalene with zero- and two-valent iron in the presence of persulfate

An initial set of 12 kinetic experiments was carried out to remove naphthalene from an aqueous effluent by photo-Fenton involving Fe⁰ and Fe²⁺ at two different concentrations of H₂O₂ (150 and 300?mg?L^?1) and three different pHs (3, 5, and 7) (2²×3¹ experiments). The rate constants (k) for the reaction of naphthalene degradation by involving Fe²⁺ as reactant were in general higher than those with Fe⁰, but the use of Fe²⁺ increased the concentration of naphthalene at equilibrium (C_e) when compared with the same response obtained with Fe⁰ at analogous conditions. A second set of twelve kinetic experiments of photo-Fenton degradation was also performed with persulfate as additive at the conditions already reported, but at a constant concentration of H₂O₂ of 150?mg?L^?1 (2¹×3¹ experiments with NaCl +2¹×3¹ experiments without NaCl). In almost all the runs in which only the source of iron was varied, k from the kinetic data involving Fe²⁺ was higher than that involving Fe⁰, but no difference was observed in terms of C_e that was always zero. The addition of persulfate to treat the effluent either containing or not containing salt enhanced the chemical kinetics, and shifted the equilibrium toward the full removal of naphthalene. A final set of nine experiments of UV photo degradation of naphthalene by involving persulfate without iron, with Fe⁰ and Fe²⁺ in the pH range from 3 to 7 (3² experiments) mainly showed that the use of H₂O₂ may be avoided to remove rapidly and completely naphthalene from wastewater.     

High Spatial Resolution Mapping of Localized Surface Plasmon Resonances in Single Gallium Nanoparticles

Plasmonics has emerged as an attractive field driving the development of optical systems in order to control and exploit light–matter interactions. The increasing interest around plasmonic systems is pushing the research of alternative plasmonic materials, spreading the operability range from IR to UV. Within this context, gallium appears as an ideal candidate, potentially active within a broad spectral range (UV–VIS–IR), whose optical properties are scarcely reported. Importantly, the smart design of active plasmonic materials requires their characterization at high spatial and spectral resolution to access the optical fingerprint of individual nanostructures, attainable by transmission electron microscopy techniques (i.e., by means of electron energy‐loss spectroscopy, EELS). Therefore, the optical response of individual Ga nanoparticles (NPs) by means of EELS measurements is analyzed, in order to spread the understanding of the plasmonic response of Ga NPs. The results show that single Ga NPs may support several plasmon modes, whose nature is extensively discussed.     

A comparison of graph-based word sense induction clustering algorithms in a pseudoword evaluation framework

This article presents a comparison of different Word Sense Induction (wsi) clustering algorithms on two novel pseudoword data sets of semantic-similarity and co-occurrence-based word graphs, with a special focus on the detection of homonymic polysemy. We follow the original definition of a pseudoword as the combination of two monosemous terms and their contexts to simulate a polysemous word. The evaluation is performed comparing the algorithm’s output on a pseudoword’s ego word graph (i.e., a graph that represents the pseudoword’s context in the corpus) with the known subdivision given by the components corresponding to the monosemous source words forming the pseudoword. The main contribution of this article is to present a self-sufficient pseudoword-based evaluation framework for wsi graph-based clustering algorithms, thereby defining a new evaluation measure (top2) and a secondary clustering process (hyperclustering). To our knowledge, we are the first to conduct and discuss a large-scale systematic pseudoword evaluation targeting the induction of coarse-grained homonymous word senses across a large number of graph clustering algorithms.     

Onion under Microscope: An in-depth analysis of the Tor Web

World Wide Web - Tor is an open source software that allows accessing various kinds of resources, known as hidden services, while guaranteeing sender and receiver anonymity. Tor relies on a free,...     

Pleiotropic Roles of NOTCH1 Signaling in the Loss of Maturational Arrest of Human Osteoarthritic Chondrocytes

Notch signaling has been identified as a critical regulator of cartilage development and homeostasis. Its pivotal role was established by both several joint specific Notch signaling loss of function mouse models and transient or sustained overexpression. NOTCH1 is the most abundantly expressed NOTCH receptors in normal cartilage and its expression increases in osteoarthritis (OA), when chondrocytes exit from their healthy “maturation arrested state” and resume their natural route of proliferation, hypertrophy, and terminal differentiation. The latter are hallmarks of OA that are easily evaluated in vitro in 2-D or 3-D culture models. The aim of our study was to investigate the effect of NOTCH1 knockdown on proliferation (cell count and Picogreen mediated DNA quantification), cell cycle (flow cytometry), hypertrophy (gene and protein expression of key markers such as RUNX2 and MMP-13), and terminal differentiation (viability measured in 3-D cultures by luminescence assay) of human OA chondrocytes. NOTCH1 silencing of OA chondrocytes yielded a healthier phenotype in both 2-D (reduced proliferation) and 3-D with evidence of decreased hypertrophy (reduced expression of RUNX2 and MMP-13) and terminal differentiation (increased viability). This demonstrates that NOTCH1 is a convenient therapeutic target to attenuate OA progression.     

Squalenoyl nanomedicines as potential therapeutics

Nucleoside analogues display significant anticancer or antiviral activity by interfering with DNA synthesis. However, there are some serious restrictions to their use, including their rapid metabolism and the induction of resistance. We have discovered that the linkage of nucleoside analogues to squalene leads to amphiphilic molecules that self-organize in water as nanoassemblies of 100-300 nm, irrespective of the nucleoside analogue used. The squalenoyl gemcitabine exhibited superior anticancer activity in vitro in human cancer cells and gemcitabine-resistant murine leukemia cells, and in vivo in experimental leukemia both after intravenous and oral administration. The squalenoylation of other antiretroviral nucleosides also led to more potent drugs when tested in primary cultures of HIV-infected lymphocytes. Thus, the squalenoylation is an original technology platform for generating more potent anticancer and antiviral nanomedicines.