Investigation of Yb(III)-PVC membrane interfacial interaction by semiempirical PM6/SPARKLE method based on 1,10-phenanthroline-5,6-dione as a suitable neutral ionophore

The initiation of atherosclerosis involves retention of colloidal atherogenic lipoproteins, primarily low density lipoprotein (LDL), in the arterial intima. This retention occurs when LDL binds to smooth muscle cell extracellular matrix (SMC ECM), and is enhanced by lipoprotein lipase (LpL) and sphingomyelinase (Smase). Here we use a fluorescence assay and dynamic light scattering to study the individual and combined effects of these two enzymes on LDL aggregation. Our results show: (1) LpL is self-sufficient to induce LDL aggregation with aggregate sizes up to ~400 nm; (2) Smase induces LDL aggregation due to generation of ceramide and subsequent hydrophobic interactions; (3) Smase hydrolysis of LpL-induced LDL aggregates does not cause further aggregation and results in a ~3-fold diminished production of ceramide, while LpL treatment of Smase-induced aggregates does enhance aggregation; (4) The simultaneous addition of LpL and Smase causes increased variability in aggregation with final sizes ranging from 50 to 110 nm. Our data suggest a new proatherogenic function for LpL, namely, bridging between LDL particles causing their aggregation and consequently enhanced retention by SMC ECM. The mechanism of LpL-and-Smase-mediated LDL aggregation and binding to SMC ECM provides specific points of intervention to design novel effective antiatherogenic therapeutics.     

UV effects on marine planktonic food webs: A synthesis of results from mesocosm studies

UV irradiance has a broad range of effects on marine planktonic organisms. Direct and indirect effects on individual organisms have complex impacts on food-web structure and dynamics, with implications for carbon and nutrient cycling. Mesocosm experiments are well suited for the study of such complex interrelationships. Mesocosms offer the possibility to conduct well-controlled experiments with intact planktonic communities in physical, chemical and light conditions mimicking those of the natural environment. In allowing the manipulation of UV intensities and light spectral composition, the experimental mesocosm approach has proven to be especially useful in assessing the impacts at the community level. This review of mesocosm studies shows that, although a UV increase even well above natural intensities often has subtle effects on bulk biomass (carbon and chlorophyll), it can significantly impact the food-web structure because of different sensitivity to UV among planktonic organisms. Given the complexity of UV impacts, as evidenced by results of mesocosm studies, interactions between UV and changing environmental conditions (e.g. eutrophication and climate change) are likely to have significant effects on the function of marine ecosystems.     

High temperature stability and photocatalytic activity of nanocrystalline anatase powders with Zr and Si co-dopants

TiO₂ nanopowders doped by Si and Zr were prepared by sol–gel method. The effects of Si and Zr doping on the structural, optical, and photo-catalytic properties of titania nanopowders have been studied by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and UV–Vis absorption spectroscopy. XRD results suggest that adding impurities has a significant effect on anatase phase stability, crystallinity, and particle size of TiO₂. Titania rutile phase formation in ternary system (Ti–Si–Zr) was inhibited by Zr⁴⁺ and Si⁴⁺ co-doped TiO₂ in high temperatures (500–900 °C) and 36 mol% anatase composition is retained even after calcination at 1,000 °C. The photocatalyst activity was evaluated by photocatalytic degradation kinetics of aqueous methylen orange under visible radiation. The results show that the photocatalytic activity of the 20 %Si and 15 %Zr co-doped TiO₂ nanopowders have a larger degradation efficiency than pure TiO₂ under visible light.     

Enhanced photoinduced super-hydrophilicity in sol–gel TiO2 thin films with co-doped Sn/Nb

In this work, Sn and Nb co-doped TiO₂ were coated on glazed porcelain substrates via sol–gel dip coating method. Field emission-scanning electron microscopy, transmission electron microscopy, and UV–vis spectrophotometer were used to evaluate thickness and optical properties of the thin films. Surface chemical state of thin films was examined by atomic X-ray photoelectron spectroscopy. Water contact angle on the film surfaces was measured by a contact angle analyzer under solar light irradiation. The optical results indicated that Sn/Nb dopant in TiO₂ thin film changed the absorption edge from ultraviolet to visible light and exhibited excellent photo-catalytic ability for degradation of methylene blue solution under solar irradiation. Wettability results indicated that Sn and Nb dopant ions had significant effect on the hydrophilicity property of thin films.     

Electrochemical Behavior of Glucose Oxidase Immobilized on Pd‐Nanoparticles Decorated Ionic Liquid Derived Fibrillated Mesoporous Carbon

Pd nanoparticles with an average diameter of 5 nm were decorated on the surface of ionic liquid derived fibrillated mesoporous carbon (IFMC) to prepare a novel nano‐hybrid material (Pd@IFMC). Thereafter, glucose oxidase was immobilized on Pd@IFMC modified glassy carbon electrode to fabricate an enzymatic glucose biosensor. A pair of well‐defined redox peaks was recorded for direct electron transfer of the immobilized glucose oxidase at the formal potential of ? 0.418 V with a peak to peak separation of 25 mV. Electron transfer rate constant of was calculated to be 14.6 s^?1. The response of fabricated biosensor was linear towards glucose concentration.     

Characterization and performance of immobilized amylase and cellulase

The performance of cellulase and amylase immobilized on siliceous supports was investigated. Enzyme uptake onto the support depended on the enzyme source and immobilization conditions. For amylase, the uptake ranged between 20 and 60%, and for cellulase, 7–10%. Immobilized amylase performance was assessed by batch kinetics in 100–300 g/L of corn flour at 65°C. Depending on the substrate and enzyme loading, between 40 and 60% starch conversion was obtained. Immobilized amylase was more stable than soluble amylase. Enzyme samples were preincubated in a water bath at various temperatures, then tested for activity. At 105°C, soluble amylase lost ∼55% of its activity, compared with ∼30% loss for immobilized amylase. The performance of immobilized cellulase was evaluated from batch kinetics in 10 g/L of substrate (shredded wastepaper) at 55°C. Significant hydrolysis of the wastepaper was also observed, indicating that immobilization does not preclude access to and hydrolysis of insoluble cellulose.     

A coordinating contract for transshipment in a two-company supply chain

We study a supply chain with two independent companies producing an identical product and cooperating through transshipment. Previous studies of this chain show that only under certain conditions, linear transshipment prices could be found that induce the companies to choose the first best production quantities. Moreover, even if such transshipment prices do exist, they result in a unique division of total expected profit and thus they cannot accommodate arbitrary divisions of the profit. Using the Generalized Nash Bargaining Solution, we derive coordinating transshipment prices that always give rise to a coordinating contract for the chain. This contract relies on an implicit pricing mechanism.     

Asymptotic properties of some non-autonomous systems in Banach spaces

Let X be a reflexive Banach space. We introduce the notion of weakly almost nonexpansive sequences (xn)_n?0 in X, and study their asymptotic behavior by showing that the nonempty weak ω-limit set of the sequence (xn/n)_n?1 always lies on a convex subset of a sphere centered at the origin of radius d=limn→∞‖xn/n‖. Subsequently we apply our results to study the asymptotic properties of unbounded trajectories for the quasi-autonomous dissipative system , where A is an accretive (possibly multivalued) operator in X×X, and f−f_∞∈Lp((0,+∞);X) for some f_∞∈X and 1?p<∞. These results extend recent results of J.S. Jung and J.S. Park [J.S. Jung, J.S. Park, Asymptotic behavior of nonexpansive sequences and mean points, Proc. Amer. Math. Soc. 124 (1996) 475-480], and J.S. Jung, J.S. Park, and E.H. Park [J.S. Jung, J.S. Park, E.H. Park, Asymptotic behaviour of generalized almost nonexpansive sequences and applications, Proc. Nonlinear Funct. Anal. 1 (1996) 65-79], as well as our results cited below containing previous results by several authors.     

Robust placement and tuning of UPFC via a new multiobjective scheme‐based fuzzy theory

This article addresses a new modified honey bee mating optimization namely multiobjective honey bee mating optimization (MOIHBMO) based fuzzy multiobjective methodology for optimal locating and parameter setting of unified power flow controller (UPFC) in a power system for a long‐term period. One of the profits obtained by UPFC placement in a transmission network is the reduction in total generation cost due to its ability to change the power flow pattern in the network. Considering this potential, UPFC can be also used to remove or at least mitigate the congestion in transmission networks. The other issue in a power system is voltage violation which could even render the optimal power flow problem infeasible to be solved. Voltage violation could be also mitigated by proper application of UPFC in a transmission system. These objectives are considered simultaneously in a unified objective function for the proposed optimization algorithm. At first, these objectives are fuzzified and designed to be comparable against each other and then they are integrated and introduced to a MOIHBMO method to find the solution which maximizes the value of integrated objective function in a 3‐year planning horizon, considering the load growth. A power injection model is adopted for UPFC. Unlike, the most previous works in this field the parameters of UPFC are set for each load level to avoid inconvenient rejection of more optimal solutions. IEEE reliability test system is used as an illustrative example to show the effectiveness of the proposed method. © 2014 Wiley Periodicals, Inc. Complexity 21: 126–137, 2015