Oxidative stability of structured lipids produced from borage (<Emphasis Type="Italic">Borago officinalis</Emphasis> L.) and evening primrose (<Emphasis Type="Italic">Oenothera biennis</Emphasis> L.) oils with docosahexaenoic acid

This study utilized γ-linolenic acid (18∶3n−6; GLA)-rich borage oil (BO) and evening primrose oil (EPO) for the synthesis of structured lipids (SL) and compared the oxidative stability of the products with those of unmodified BO and EPO as controls. Immobilized Novozym 435 lipase from Candida antarctica was used as the biocatalyst for SL production. BO or EPO eas enzymatically modified with docosahexaenoic acid (22∶6n−3; DHA), as the acyl donor, to produce SI. The SI were characterized and their oxidative stabilities evaluated. Among the oils examined, SL gave rise to higher quantities (P≤0.05) of conjugated dienes, TBARS, and headspace volatiles as compared to their unmodified counterparts. Results indicated that modified oils were less stable than their unmodified counterparts. The double bond index (DBI) and methylene bridge index (MBI) of oils decreased (P<0.05) during oxidation in the more unsaturated oils. An attempt was made to correlate various parameters of oxidation with DBI and MBI of oils; correlation coefficients (−r) were within the range of 0.574–0.973. This suggests that indicators such as DBI and MBI can reflect oxidative stability of oils.     

Open-loop and feedback-controlled mouse cursor movements in linear paths

Path length (A), path width (W) and movement direction (θ) are identified as the main factors affecting visually-controlled movement times in linear paths. Effects of A and W are well described by Drury's ( 1971 . Movements with lateral constraint. Ergonomics, l4 (2), 293-305.) model in which movement time is linearly related to the ratio of A/W. At low A/W values, departure from linearity has been identified but not investigated in detail. Data are presented for both open-loop and feedback-controlled movements in linear paths at 0, 60 and 150° movement directions. Movement amplitude and path width were varied over a wide range to determine the effects of A and (A/W) on movement time. Movements were found to be made ballistically or in open-loop mode when the ratio (A/W) was less than about 8 to 10 and the movement times were linearly related to √A for all angles of movement. Feedback-controlled movements followed Drury's law; ballistic movements had movement speed linear with √A. PRACTITIONER SUMMARY: Many tasks require manoeuvring equipment or devices through a path of limited width. These movements can be made with or without feedback control, depending on the path constraints. The conditions for the two forms of movement are determined in this research.     

Acetate adsorption and metal overlayers on electrode surfaces

Acetate adsorbs onto platinum surfaces under moderate conditions and the presence of acetate on the electrode surface is apparent by voltammetric studies. The adsorption of acetate lends an unusual stability to layers of zinc acetate on the electrode surface. The reduction of an oxidized platinum surface under a zinc acetate coating is sensitive to polar organic molecules in the bulk solution. This sensitivity may provide an avenue to a new class of analytical sensors.     

Nanoscale Charge Percolation Analysis in Polymer‐Sorted (7,5) Single‐Walled Carbon Nanotube Networks

The current percolation in polymer‐sorted semiconducting (7,5) single‐walled carbon nanotube (SWNT) networks, processed from solution, is investigated using a combination of electrical field‐effect measurements, atomic force microscopy (AFM), and conductive AFM (C‐AFM) techniques. From AFM measurements, the nanotube length in the as‐processed (7,5) SWNTs network is found to range from ≈100 to ≈1500 nm, with a SWNT surface density well above the percolation threshold and a maximum surface coverage ≈58%. Analysis of the field‐effect charge transport measurements in the SWNT network using a 2D homogeneous random‐network stick‐percolation model yields an exponent coefficient for the transistors OFF currents of 16.3. This value is indicative of an almost ideal random network containing only a small concentration of metallic SWNTs. Complementary C‐AFM measurements on the other hand enable visualization of current percolation pathways in the xy plane and reveal the isotropic nature of the as‐spun (7,5) SWNT networks. This work demonstrates the tremendous potential of combining advanced scanning probe techniques with field‐effect charge transport measurements for quantification of key network parameters including current percolation, metallic nanotubes content, surface coverage, and degree of SWNT alignment. Most importantly, the proposed approach is general and applicable to other nanoscale networks, including metallic nanowires as well as hybrid nanocomposites.     

Removal of Sulfate,Phosphate and Colored Substances in Wastewater Effluents using Feldspar

Feldspar, among many natural substances such as termitemount-clay, saw-dust, kaolinite and dolomite, offers asignificant removal ability for sulfate, phosphate, and coloredsubstances. Optimization of experimental parameters such assolution pH and flow rate reveals, that the maximum efficiency forremoval of phosphate, sulfate, and colored substances is about42, 52, and 73% respectively. X-ray diffraction, adsorptionisotherm and recovery studies suggest, that the removal processof anions occurs via ion exchange in conjunction with surfaceadsorption. Furthermore, reaction rate studies indicate thatthe removal of the selected pollutants by feldspar follows first-order kinetics. Although the percent removal, under the optimized conditions, is higher for laboratory prepared solutions, efficiency is a little less for industrial effluentsdue to interferent effects.     

Positional distribution of FA in TAG of enzymatically modified borage and evening primrose oils

Stereospecific analysis was carried out to establish positional distribution of FA in the TAG of DHA, EPA, and (EPA+DHA)-enriched oils. In this study, TAG of enzymatically modified oils were purified using a silicic acid column. The TAG were then subjected to positional distribution analysis using a modified procedure involving reductive cleavage with Grignard reagent. The results showed that in DHA-enriched borage oil (BO), DHA was randomly distributed over the three positions of TAG, whereas γ-linolenic acid (GLA) was mainly esterified at the sn-2 and-3 positions. In DHA-enriched evening primrose oil (EPO), however, DHA and GLA were concentrated in the sn-2 position. In EPA-enriched BO, EPA was randomly distributed over the three positions of TAG, similar to that observed for DHA. In EPA-enriched EPO, however, this FA was mainly located at the primary positions (sn-1 and sn-3) of TAG. In both oils, GLA was preferentially esterified at the sn-2 position. In (EPA+DHA)-enriched BO, EPA and DHA were mainly esterified at the sn-1 and -3 positions of TAG, whereas GLA was mainly located at the sn-2 position. In (EPA+DHA)-enriched EPO, GLA was mainly located at the sn-2 and-3 positions; EPA was preferentially esterified at the sn-1 and-3 positions, and DHA was found mainly at the sn-3 position.     

Implementation of OpenFlow based cognitive radio network architecture: SDN&R

Wireless Networks - The static conventional network architecture is ill-suited to the growing management complexity and highly dynamic wireless network topologies. Software Defined Radio systems...     

Enzyme-assisted acidolysis of menhaden and seal blubber oils with γ-linolenic acid

Oils containing both n−3 and n−6 fatty acids have important clinical and nutritional applications. Lipase-catalyzed acidolysis of seal blubber (SBO) and menhaden oils (MO) with γ-linolenic acid (GLA) was carried out in hexane. The process variables studied for lipase-catalyzed reaction were concentration of enzyme (100–700 units/g of oil), reaction temperature (30–60°C), reaction time (0–48 h), and mole ratio of GLA to triacylglycerols (TAG) (1∶1 to 5∶1). Two lipases chosen for acidolysis reaction were from Pseudomonas species (PS-30) and Mucor miehei. Lipase PS-30 was chosen over Mucor (also known as Rhizomucor) miehei to catalyze the acidolysis reaction owing to higher incorporation of GLA. For the acidolysis reaction, optimal conditions were a 3∶1 mole ratio of GLA to TAG, reaction temperature of 40°C, reaction time of 24 h, and an enzyme concentration of 500 units/g of oil. Under these conditions, incorporation of GLA was 37.1% for SBO and 39.6% for MO.     

Realization of Mobile Femtocells: Operational and Protocol Requirements

Femtocells are commissioned in wide range of commercial systems, such as CDMA, GSM, LTE, Wi-Fi, and WiMAX, and offer economically viable solutions to improve network scalability and indoor coverage. The ability to offer multitude of context-aware and value added services, and per-user customization have caught world-wide research interest on femtocells. In this article, we have investigated the feasibility to use femtocells as short-range mobile base stations, and discussed the demanding architectural requirements and challenges. The protocol stack on legacy femtocells must be modified to realize mobility. Mobility introduces new challenges in security and user privacy. Firstly, we analyze several candidate mobility protocols that are deployable on Mobile Femtocells (MFs). Among them, Host Identity Protocol (HIP) was chosen due to enhanced support in flexible mobility, security and end-user privacy. Secondly, we propose the indispensable modifications that enable device mobility, and the suitable transport architecture options based on direct IP links and relay chains. Finally, with the simulation results, the proposal is verified, and the architectural options are evaluated. That, in turn, proves the proposed mobility protocol has low latency in location locking with respect to another competing protocol and low resource utilization as it is depicted from mean round trip time.     

Investigation of kinetics of Cr(VI)-fired brick clay interaction

Fired brick clay is an excellent sorbent for the removal of heavy metal ions from waste water, owing to the availability of pores and interlayer spacing. Consequently, heat treatment of brick clay significantly affects the extent of interaction between the brick clay sorbent and adsorbates. The interaction between Cr(VI), available as Cr(2)O(7)(2-), and brick clay particles fired at temperatures between 200 °C and 600 °C follows pseudo second order kinetics, and the method of initial rates leads to the estimation of the average rate of the interaction process. Kinetics modeling suggests that the mass transfer of the interaction be mainly controlled by time-dependent intraparticle diffusion, as well as immobilization of Cr(VI) species within interlayer structure of the brick clay matrix and interparticle diffusion, both of which are time-independent.