Dielectric dispersion in Li2O–MoO3–B2O3 glass system doped with V2O5

Li₂O–MoO₃–B₂O₃ glasses containing different amounts of V₂O₅, ranging from 0 to 1.5 mol%, were prepared. The dielectric properties (viz., constant ′, loss tan δ, AC conductivity σ_ac over a wide range of frequency and temperature) have been studied as a function of the concentration of vanadium ions. The variation of AC conductivity with the concentration of V₂O₅ passes through a maximum at 0.8 mol% V₂O₅. In the high-temperature region, the AC conduction seems to be connected with the mixed conduction, viz., electronic and ionic conduction. The dielectric relaxation effects exhibited by these glasses have been analyzed quantitatively by pseudo Cole–Cole plot method and the spreading of relaxation times has been established. Further analysis of these results has been carried out with the aid of the data on ESR, IR and optical absorption spectra.     

Handover in LTE-advanced wireless networks: state of art and survey of decision algorithm

The increasing demand for mobile communication calls for improvements to network operating services in terms of capacity, coverage, and Quality of Services (QoS). Ensuring QoS is one of the challenges faced by wireless network operators, which include the provision of high mobility speeds, thus the implementation of a seamless and fast handover between network cells is a prominent issue that must be addressed, especially when fulfilling QoS prerequisites. Long Term Evolution (LTE)/LTE-Advance has met these demands of QoS through the use of a new Radio Access Network and distribution of Radio Resource Management including the handover decision technique to evolve NodeB instead of relying on centralized control. In this paper, we review the control plane structure of LTE/LTE-A and present a comprehensive discussion of handover procedures such as the phases, techniques, requirements, features, and challenges involved. According to the overview of the handover decision phase, we surveyed and classified the present handover decision algorithms for a LTE-A system-based technology in regard to the primary handover decision technique. For each class, we describe in detail the fundamental operations and decision parameters using representative algorithms. A summary of input parameters, techniques, and performance evaluation of the handover decision algorithms concludes this work.     

Reactive ion etching of GaN and AlGaN/GaN assisted by Cl2/BCl3

This work reports on the latest results of etching of different Al _x Ga_1?x N/GaN heterostructures in relation to percentage composition of aluminum. The etching processes were carried out in a reactive ion etching (RIE) system using the mixture of BCl₃/Cl₂/Ar. The topography of the heterostructures surfaces and the slope were controlled using atomic force microsopy (AFM) technique. The photoluminescence spectra were used to determine the surface damage and to calculate the Al content in AlGaN/GaN heterostructures commonly used for high electron mobility transistors (HEMTs) fabrication.     

Effects of dispersed oil exposure on the bioaccumulation of polycyclic aromatic hydrocarbons and the mortality of juvenile Liza ramada

Dispersing an oil slick is considered to be an effective response to offshore oil spills. However, in nearshore areas, dispersant application is a controversial countermeasure: environmental benefits are counteracted by the toxicity of dispersant use. In our study, the actual toxicity of the dispersant response technique in the nearshore areas was evaluated through an experimental approach using juvenile Liza ramada. Fish were contaminated via the water column (i) by chemically dispersed oil, simulating dispersant application, (ii) by dispersant, as an internal control of chemical dispersion, (iii) by mechanically dispersed oil, simulating only the effect of natural mixing processes, without dispersant application, and (iv) by the water soluble fraction of oil, simulating the toxicity of an oil slick before recovery. Bioconcentrations of polycyclic aromatic hydrocarbons (PAH) and mortality were evaluated, and related to both total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) concentrations in seawater.Fish exposed to chemically dispersed oil showed both a higher bioconcentration of PAH and a higher mortality than fish exposed to either the water soluble fraction of oil or the mechanically dispersed oil. These results suggest that (i) dispersion is a more toxic response technique than containment and recovery of the oil slick; (ii) in turbulent mixing areas, dispersant application increases the environmental risk for aquatic organisms living in the water column. Even if the experimental aspects of this study compel us to be cautious with our conclusions, responders could consider these results to establish a framework for dispersant use in nearshore areas.     

Immobilization of Saccharomyces cerevisiae in Gelatin Cross-Linked with Chromium Ions for Conversion of Sucrose by Intracellular Invertase

A novel immobilized biocatalyst with invertase (β-D-fructofuranosidase, E.C.3.2.1.26) activity was prepared by immobilizing Saccharomyces cerevisiae cells into gelatin by using chromium salts. The effect of chromium salts on cell growth of free and immobilized cells was investigated, and optimum concentrations for chromium acetate and chromium sulfate were found to be 0.016 M and 0.008 M, respectively. Since a medium feeding strategy was applied, higher enzymatic activities were obtained with developed biocatalyst compared to free S. cerevisiae cells. Immobilized samples could be used 10 times in a 30-day period with negligible activity loss. After storing it at 25°C for 28 days, our biocatalyst was used 15 times with 2-day intervals with only a slight amount of activity decrease. As a result we managed to produce a very stable biocatalyst with high invertase activity using an inexpensive methodology.     

Three-Dimensional Micromechanics-Based Constitutive Framework for Analysis of Pultruded Composite Structures

A new 3D micromechanics-based framework is proposed for the nonlinear analysis of pultruded fiber-reinforced polymeric composites. The proposed 3D modeling framework is a nested multiscale approach that explicitly recognizes the response of the composite systems (layers) within the cross section of the pultruded member. These layers can have reinforcements in the form of roving, continuous filament mat (CFM), and∕or woven fabrics. Different 3D micromechanical models for the layers can be used to recognize the basic response of the fiber and matrix materials. The framework is implemented with both shell and 3D finite elements. The 3D lamination theory is used to generate a homogenized nonlinear effective response for a through-thickness representative stacking sequence. The proposed modeling framework for pultruded composites is used to predict the stiffness and nonlinear stress-strain response of E-glass∕vinylester pultruded materials reinforced with roving and CFM. The roving layer is idealized using a 3D nonlinear micromechanics model for a unidirectional fiber-reinforced material. A simple nonlinear micromechanics model for the CFM layer is also applied. The proposed model shows very good predictive capabilities of the overall effective properties and the nonlinear response of pultruded composites, based on the in situ material properties, and the volume fractions of the constituents. Experimental data from off-axis tests of pultruded plates under uniaxial compression are used to verify the proposed model. The proposed framework can be easily incorporated within displacement-based finite-element models of composite structures.     

Modeling Intermittent Drying Using an Adaptive Neuro-Fuzzy Inference System

Artificial intelligence systems such as artificial neural networks (ANN) and fuzzy inference systems (FIS) are widely accepted as a technology offering an alternative way to tackle complex and ill-defined problems. The advantages of a combination of ANN and FIS are obvious. This article presents the application of a hybrid neuro-fuzzy system called adaptive-network-based fuzzy inference system (ANFIS) to time dependent drying processes and is illustrated by an application to model intermittent drying of grains in a spouted bed. An introduction to the ANFIS modeling approach is also presented. The model showed good performance in terms of various statistical indices.     

Nasal nitric oxide is increased in allergic rhinitis

BACKGROUND: Nitric oxide (NO) plays a major role in the regulation of vascular tone and in non-specific host defence. The epithelium in the paranasal sinuses was recently identified as the major site of NO production in the upper airways. OBJECTIVE: To investigate NO status in allergic rhinitis, we compared the NO concentration in the nasal cavities of control subjects (n = 19) and in patients with allergic rhinitis (n = 36) with symptoms (WS, n = 17) or without symptoms (WOS, n = 19) on the day of the test. METHODS: NO concentration was measured using a chemiluminescent analyser aspiring from each nasal cavity at a sampling flow rate of 0.7 L/min, before and 10 min after administration of a nasal vasoconstrictor. RESULTS: The mean NO concentration (+/- SE) in the control was 235 +/- 11 ppb and 225 +/- 9 ppb in the right and left nostrils respectively, and was decreased by 14% and 12% by the nasal vasoconstrictor (P < 0.001). The NO concentration in patients with allergic rhinitis was significantly higher in the right and left nostrils (382 +/- 20 ppb and 396 +/- 28 respectively, P < 0.0001 versus control). All WOS patients demonstrated normal or increased NO concentrations in both nostrils, whereas two WS patients showed decreased NO concentrations in the left nostril. Inhalation of a nasal vasoconstrictor increased NO concentration by 6% and 27% in the right and left nostrils respectively in WS patients. CONCLUSION: Nasal NO concentration is increased in patients with allergic rhinitis. Interestingly, patients without symptoms on the day of the test also showed a clear-cut increase in nasal NO production, which could reflect a permanent inflammation of the sinus mucosa.     

Magnetic Helical Microswimmers Functionalized with Lipoplexes for Targeted Gene Delivery

Artificial micro‐/nanoswimmers have various potential applications including minimally invasive diagnosis and targeted therapies, environmental sensing and monitoring, cell manipulation and analysis, and lab‐on‐a‐chip devices. Inspired by natural motile bacteria such as E. Coli, artificial bacterial flagella (ABFs) are one kind of magnetic helical microswimmers. ABFs can perform 3D navigation in a controllable fashion with micrometer precision under low‐strength rotating magnetic fields (<10 mT) and are promising tools for targeted drug delivery in vitro and in vivo. In this work, the successful wirelessly targeted and single‐cell gene delivery to human embryonic kidney (HEK 293) cells using ABFs loaded with plasmid DNA (pDNA) in vitro is demonstrated for the first time. The ABFs are functionalized with lipoplexes containing pDNA to generate functionalized ABFs (f‐ABFs). The f‐ABFs are steered wirelessly by low‐strength rotating magnetic fields and deliver the loaded pDNA into targeted cells. The cells targeted by f‐ABFs are successfully transfected by the transported pDNA and expressed the encoding protein. These f‐ABFs may also be useful for in vivo gene delivery and other applications such as sensors, actuators, cell biology, and lab‐on‐a‐chip environments.