Heme oxygenase induction by cyanidin-3-O-beta-glucoside in cultured human endothelial cells

The aim of the present research was to investigate the effect of cyanidin-3-O-beta-glucoside (C3G) on heme oxygenase-1 (HO-1), endothelial nitric oxide synthase (eNOS), inducible NOS (iNOS) and dimethylarginine dimethylamino hydrolase-2 (DDAH-2) expression in cultured endothelial cells. Different concentrations (0.00625-250 microM) of C3G were tested in order to investigate possible beneficial and harmful effects of C3G. Our data demonstrated that C3G increased the induction of eNOS and HO-1 in a dose-dependent manner. Higher concentration (62.5-250 microM) also resulted in increase of isoprostane, cGMP and PGE2 levels and in induction of iNOS with consequent oxidative stress. In conclusion, our data evidence that C3G may exert various protective effects against endothelial dysfunction, whereas potentially harmful effects of C3G appear to be limited to concentrations very difficult to be reached in physiological conditions unless there is abundant oral supplementation.     

A Computer‐Aided Model for the Simulation of Railway Ballast by Random Sequential Adsorption Process

This article presents a computer‐aided multistage methodology for the simulation of railway ballasts using the Random Sequential Adsorption (RSA – 2D domain) paradigm. The primary stage in this endeavor is the numerical generation of a synthetic sample by a “particle sizing and positioning” process followed by a “compaction” process. The synthetic samples of ballast are then visualized in the Computer‐Aided Design (CAD) environment. The outcomes of the simulation are analyzed by comparison with the results of an experimental investigation carried out using a methacrylate container in which real samples of railway ballast are formed. A test of model reliability is carried out between the aggregates number and the grading curves of the synthetic sample and the real one. A validation is therefore performed using the ground‐penetrating radar (GPR) nondestructive testing (NDT) method and the finite‐difference time‐domain (FDTD) simulation developed in a computer‐aided environment. The results prove the viability and the applicability of the proposed modeling for the assessment of railway ballast conditions.     

Influence of diazo pigment on polycarbonate photodegradation

The photostability of polymeric systems can be extensively affected by the presence of dyes and pigments. Achromatic pigments such as carbon black are known as effective stabilizers for polymers, while pigments such as those based on metals oxides may accelerate photodegradation in polymers. Despite innumerous studies addressed to achromatic pigments, the effects and action mechanisms of chromatic pigments on polymer stability are not well established. In this work, an effective photostabilizer action on polycarbonate was verified by the incorporation of a red diazo type condensation pigment. This pigment was incorporated into polycarbonate in an extruder at a concentration of 1 wt %. Injection molded specimens of this material were submitted to photochemical aging following the recommendations of ASTM G‐53. The nonaged and aged specimens were characterized by mechanical testing, infrared spectroscopy, UV/visible absorption and fluorescence spectroscopies, and electron spin resonance. The absorption of the UV radiation by the pigment and subsequent quenching by the internal conversion energy process is the probable stabilization mechanism involved in this polymeric system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Scanning gate imaging of quantum point contacts and the origin of the 0.7 anomaly

The origin of the anomalous transport feature appearing at a conductance G ≈ 0.7 × (2e²/h) in quasi-1D ballistic devices-the so-called 0.7 anomaly-represents a long standing puzzle. Several mechanisms have been proposed to explain it, but a general consensus has not been achieved. Proposed explanations have been based on quantum interference, the Kondo effect, Wigner crystallization, and other phenomena. A key open issue is whether the point defects that can occur in these low-dimensional devices are the physical cause behind this conductance anomaly. Here we adopt a scanning gate microscopy technique to map individual impurity positions in several quasi-1D constrictions and correlate these with conductance characteristics. Our data demonstrate that the 0.7 anomaly can be observed irrespective of the presence of localized defects, and we conclude that the 0.7 anomaly is a fundamental property of low-dimensional systems.

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An overview of the verification of SET

This paper describes the verification of Secure Electronic Transaction (SET), an e-commerce protocol by VISA and MasterCard. The main tasks are to comprehend the written documentation, to produce an accurate formal model, to identify specific protocol goals, and, finally, to prove them. The main obstacles are the protocols complexity (due in part to its use of digital envelopes) and its unusual goals involving partial information sharing. Our verification efforts show that the protocol does not completely satisfy its goals, although the flaws are minor. The primary outcome of the project is experience with verification of enormous and complicated protocols. This paper summarizes the project – the details appear elsewhere [11, 12 , 13 ] – focusing on the issues and the conclusions.     

A practical set of miniaturized instruments for vertical profiling of aerosol physical properties

In situ atmospheric aerosol measurements have been performed from a Manta unmanned aircraft system (UAS) using recently developed miniaturized aerosol instruments. Flights were conducted up to an altitude of 3000 m (AMSL) during spring 2015 in Ny-Ålesund, Svalbard, Norway. We use these flights to demonstrate a practical set of miniaturized instruments that can be deployed onboard small UASs and can provide valuable information on ambient aerosol. Measured properties include size-resolved particle number concentrations, aerosol absorption coefficient, relative humidity, and direct sun intensity. From these parameters, it is possible to derive a comprehensive set of aerosol optical properties: aerosol optical depth, single scattering albedo, and asymmetry parameter. The combination of instruments also allows us to determine the aerosol hygroscopicity.

Copyright © 2017 American Association for Aerosol Research     

Biocomposites based on poly(lactic acid) and superabsorbent sodium polyacrylate

In this research work, biocomposites based on crosslinked particles of sodium polyacrylate, commonly used as superabsorbent polymer, and poly(l ‐lactic acid) (PLLA) were developed to obtain superabsorbent thermoplastic products, and to elucidate the role of this type of filler (i.e., polymeric crosslinked particles) on their overall physical‐mechanical behavior. Samples prepared by melt‐blending components with different ratios showed a biphasic system with a uniform distribution of particles, with diameters up to about 50 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA, that is, superabsorbent PLLA, showed excellent swelling properties, demonstrating that crosslinked particles retain their superabsorbent ability even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidenced enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles, revealing a regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open‐pore foams coded PLASAW, that is, PLASA after water treatment, produced in absence of organic solvents and chemical foaming agents, with good physicomechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45655.     

Catalytic combustion of methane on palladium single crystals

Catalytic methane combustion was studied over the palladium single crystals Pd(1 1 1), Pd(1 0 0) and Pd(1 1 0). Under lean reaction conditions at 600 K (O₂:CH₄ = 10:1), stoichiometric palladium oxide was formed with an increase in surface area by a factor of approximately two. The oxide phase formed a “cauliflower-like” surface structure composed of approximately 4 nm sized semispherical oxide agglomerates. This oxide structure was independent of the original metal single crystal orientation. The turnover rates over the oxide structure starting with metal single crystals were 0.7 s⁻¹ on Pd(1 1 1), 0.9 s⁻¹ on Pd(1 0 0) and 0.9 s⁻¹ on Pd(1 1 0) at 600 K, 160 Torr O₂, 16 Torr CH₄, 1 Torr H₂O and N₂ balance to 800 Torr, suggesting that the methane combustion reaction is independent of the initial structure of the catalyst. Methane combustion on palladium single crystals experienced an activation period in which the initial turnover rates based on the initial Pd surface area were about 1/8–1/4 of the steady-state rates determined based on the oxide surface area. This activation period was caused by the slow oxidation of palladium single crystals and concomitant surface area increase during reaction. The increase in surface area happened mostly in the first 10 min of reaction. Carbon dissolution into the crystal was not found during methane combustion under reaction conditions in excess oxygen.     

XPS and DSC Studies of Solution Cast Polystyrene/Poly(organophosphazene) Blends. II. Polystyrene/Poly(4-phenoxyphenoxy)phosphazene

Blends of polystyrene (PS) with poly(4-phenoxyphenoxy)phosphazene (PPA) were studied by differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). A third component, poly(2,6-dimethyl-1,4-phenylene ether) (PPE), was added to improve the compatibility. While DSC and XPS reveal that PS and PPA are incompatible, the presence of PPE increases the compatibility between the two polymers.