Replacement of dietary fish oil with increasing levels of linseed oil: Modification of flesh fatty acid compositions in Atlantic salmon (<Emphasis Type="Italic">Salmo salar</Emphasis>) using a fish oil finishing diet

Five groups of salmon, of initial mean weight 127±3 g, were fed increasing levels of dietary linseed oil (LO) in a regression design. The control diet contained capelin oil (FO) only, and the same oil was blended with LO to provide the experimental diets. After an initial period of 40 wk, all groups were switched to a finishing diet containing only FO for a further 24 wk. Growth and flesh lipid contents were not affected by dietary treatment. The FA compositions of flesh total lipids were linearly correlated with dietary FA compositions (r ²=0.88–1.00, P<0.0001). LO included at 50% of added dietary lipids reduced flesh DHA and EPA (20∶5n−3) concentrations to 65 and 58%, respectively, of the concentrations in fish fed FO. Feeding 100% LO reduced flesh DHA and EPA concentrations to 38 and 30%, respectively, of the values in fish fed FO. Differences between diet and flesh FA concentrations showed that 16∶0, 18∶1n−9, and especially DHA were preferentially retained in flesh, whereas 18∶2n−6, 18∶3n−3, and 22∶1n−11 were selected against and presumably utilized for energy. In fish previously fed 50 and 100% LO, feeding a finishing diet containing FO for 16 wk restored flesh DHA and EPA concentrations, to ≈80% of the values in fish fed FO throughout. Flesh DHA and EPA concentrations in fish fed up to 50% LO were above recommended intake values for humans for these EFA. This study suggests that LO can be used as a substitute for FO in seawater salmon feeds and that any reductions in DHA and EPA can be largely overcome with a finishing diethigh in FO before harvest.     

Crystallization and orientation development in fiber and film processing of polypropylenes of varying stereoregular form and tacticity

We investigated the crystallization and orientation development in melt spinning and tubular blown film extrusion of several different types of polypropylenes, including conventional high tacticity isotactic polypropylenes (iPP) and metallocene catalyst low tacticity iPPs and syndiotactic polypropylenes (sPP). The fiber and film samples were characterized by wide‐angle X‐ray diffraction (WAXD), birefringence and differential scanning calorimetry (DSC). In melt spinning iPP, we found that the mesomorphic structure of iPP is more readily formed in lower tacticity fibers, and significant amounts of hexagonal β‐form crystals are found in low tacticity iPP fibers spun at high draw‐down ratios. Low tacticity iPP fibers exhibited a significant decrease in the crystalline chain‐axis orientation at high draw‐down ratios, resulting from increased epitaxially branched lamellae. Melt‐spun sPP fibers exhibit Form I helical structure at low spinning speeds and Form III zigzag all trans structure at high spinning speeds. We found that the level of spinline stress is the governing factor for this structural change. Melt‐spun sPP fibers exhibit much higher chain‐axis (c‐axis) orientation factors (f_c) and lower birefringence than iPP fibers spun at the same spinline stresses. In tubular blown sPP films, the a‐axis of Form I unit cell tends to orient perpendicular to the film surface, while the b‐axis of monoclinic α unit cell does so in iPP blown films.     

Structure development in melt‐spinning syndiotactic polystyrene and comparison to atactic polystyrene

Syndiotactic polystyrene (s‐PS) and atactic polystyrene (a‐PS) were melt‐spun into filaments. The s‐PS filaments exhibited increasing amounts of crystallinity and orientation with increasing drawdown ratio and spinline stress. The a‐PS filaments were amorphous but exhibited birefringence. The birefringence and Hermans orientation factors for a‐PS were proportional to this spinline stress. In ice water and at low drawdown ratios, the s‐PS is glassy or mesomorphic. At higher drawdown ratios and spinline stresses, it crystallized. The crystalline form was the zigzag TTTT hexagonal α‐form. The birefringence and orientation factors of the s‐PS filaments were higher than those of the a‐PS filaments and the difference of the birefringence increased with increasing spinline stress. Mechanical testing results showed that the Young's modulus and tensile strength generally increased with increasing spinline drawdown ratio for both a‐PS and s‐PS filaments. The elongation to break was enhanced for both materials by increased chain orientation. Polym. Eng. Sci. 44:2141–2147, 2004. © 2004 Society of Plastics Engineers.     

rGO Sheets/ZnFe2O4 Nanocomposities as an Efficient Electro Catalyst Material for I3−/I− Reaction for High Performance DSSCs

In this paper, Reduced Graphene Oxide (rGO)/ZnFe₂O₄ (rZnF) nanocomposite is synthesized by a simple hydrothermal method and employed as a counter electrode (CE) material for tri-iodide redox reactions in Dye sensitized solar cells (DSSC) to replace the traditional high cost platinum (Pt) CE. X-ray diffraction analysis and High resolution Transmission electron microscopy, clearly indicated the formation of rZnF nanocomposite and also amorphous rGO sheets were smoothly distributed on the surface of ZnFe₂O₄ (ZnF) nanostructure. The rZnF-50 CE shows excellent electro catalytic activity toward I₃^? reduction, which has simultaneously been confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization measurements. A DSSC developed by rZnF-50 CE (η?=?8.71%) obtained quite higher than the Pt (η?=?8.53%) based CE under the same condition. The superior performances of rZnF-50 CE due to addition of graphene in to Spinel (ZnF) nanostructure results in creation of highly active electrochemical sites, fast electron transport linkage between CE and electrolyte. Thus it’s a promising low cost CE material for DSSCs.

     

Effects of Enhanced UV-B Radiation on Plant Chemistry: Nutritional Consequences for a Specialist and Generalist Lagomorph

Ultraviolet-B (UV-B) radiation has been increasing in temperate latitudes in recent decades and is expected to continue rising for some time. Enhanced UV-B radiation can change plant chemistry, yet the effects of these changes on mammalian herbivores are unknown. To examine the influence of enhanced UV-B radiation on nutrition of a specialist and generalist hindgut fermenter, we measured nutritional and chemical constituents of three common North American range plants, big sagebrush (Artemisia tridentata), yarrow (Achillea millefolium), and bluebunch wheatgrass (Pseudoregneria spicata), and how these changes influenced in vitro dry matter digestibility and in vivo digestibility by pygmy rabbits (Brachylagus idahoensis) and eastern cottontails (Sylvilagus floridanus). Forages were irradiated for 3 mo with ambient (1×) or supplemental (1.6×) UV-B radiation representing a 15% ozone depletion for Pullman, WA, USA. Enhanced UV-B radiation had minimal effects on the nutritional content and the tannin-binding capacity of forages. Similarly, the terpene concentration in sagebrush and yarrow was not affected by higher UV-B irradiances. Flavonoid compounds increased in sagebrush but decreased in yarrow. Rabbit preference and intake was not affected by treatment levels for any forage species and no differences were found between treatments for dry matter, fiber, protein digestibility, and apparent digestible energy.     

Relative fat oxidation is higher in children than adults

Background  

Prepubescent children may oxidize fatty acids more readily than adults. Therefore, dietary fat needs would be higher for children compared with adults. The dietary fat recommendations are higher for children 4 to 18 yrs (i.e., 25 to 35% of energy) compared with adults (i.e., 20 to 35% of energy). Despite this, many parents and children restrict dietary fat for health reasons.     

PtZn‐ETS‐2: A novel catalyst for ethane dehydrogenation

Catalysts having unprecedented selectivity toward ethane dehydrogentation were prepared by combining platinum and zinc on the surface of the titanate ETS‐2. This high surface area, sodium titanate ion exchanger affords high metal dispersion, presents many active sites to the gas stream, and is free of any pore structure that can influence mass transfer to and away from the active sites. It was determined that the addition of zinc to platinum‐loaded ETS‐2 changes the electronic properties of the metals and significantly improves the specificity of the catalyst. By changing the zinc‐to‐platinum ratio, and by manipulating the space velocity of the gas, the production of side products and coke can be suppressed or eliminated. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4367–4376, 2015     

Microstructure and multifunctional properties of liquid + polymer bicomponent structural electrolytes: Epoxy gels and porous monoliths

Multifunctional structural batteries and supercapacitors have the potential to improve performance and efficiency in advanced lightweight systems. A critical requirement is a structural electrolyte with superior multifunctional performance. We present here structural electrolytes prepared by the integration of liquid electrolytes with structural epoxy networks. Two distinct approaches were investigated: direct blending of an epoxy resin with a poly(ethylene‐glycol) (PEG)‐ or propylene carbonate (PC)‐based liquid electrolyte followed by in‐situ cure of the resin; and formation of a porous neat epoxy sample followed by backfill with a PC‐based electrolyte. The results show that in situ cure of the electrolytes within the epoxy network does not lead to good multifunctional performance due to a combination of plasticization of the structural network and limited percolation of the liquid network. In contrast, addition of a liquid electrolyte to a porous monolith results in both good stiffness and high ionic conductivity that approach multifunctional goals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42681.     

An accurate volumetric differential pressure method for the determination of hydrogen storage capacity at high pressures in carbon materials

Widely different hydrogen adsorption capacities have been reported for a variety of carbon materials which have attracted attention for hydrogen storage. This has led to doubts as to the validity of some of the claims and it has been suggested that one possible reason for the disparate hydrogen sorption capacities may lie in the inaccurate measurement of the hydrogen adsorbed. The aim of the work described in this paper was to make a contribution to this debate by developing a means and method of producing repeatable, accurate measurements of hydrogen sorption capacity in carbon materials. The apparatus developed is a volumetric differential pressure set-up operating at up to 10 MPa and the method has a conservative limit of detection of 0.1 wt% and an accuracy of ±0.05 wt%, using 1.0-2.5 g samples of the carbon materials studied. These included a carbon nanofiber sample and a series of activated carbons, the latter displaying a direct correlation between the BET effective surface area and the hydrogen sorption capacity of the materials. The amount of hydrogen adsorbed was less than 1 wt% for all the carbons examined.