bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formulation of chemically reduced graphene oxide assembly with poly(4‐vinyl pyridine) through noncovalent interaction
Authors: Lee Mi Yeon , Nam Su Hyun , Lee Jung Yup , Abdullah‐Al‐Nahain  , Lee Sangkug , Park Cheol Min , Han Chul Jong , Park Sung Young , In Insik 
Published: May 2013

ABSTRACTSoluble chemically reduced graphene oxide (RGO)/poly(4‐vinyl pyridine) (P4VP) assembly was attempted by totally noncovalent approach. Chemical reduction of P4VP/GO mixture by hydrazine produced soluble RGO/P4VP assembly with long term stability. Prepared RGO/P4VP assembly showed pH‐dependent variation of optical transmittance. Transmittance of RGO/P4VP assembly solution at pH 2.0 dramatically increased more than 200% of transmittance of assembly at pH 6. This optical transmittance change was fully reversible. The detailed morphological features of assemble was evaluated by dynamic light scattering (DLS) and atomic force microscopy (AFM). It is estimated that RGO/P4VP assemblies were well separated each other at pH 6, enabling much higher optical absorption of RGO plates. At pH 2, protonation of pyridine ring occurs and this might hamper effective noncovalent interaction between RGO plate and protonated P4VP chains, forming bigger aggregates having less chance for optical absorption. This pH‐dependent optical modulation of RGO/P4VP assembly can be useful for the designing of pH‐sensor, removable nanocatalyst, and targeted drug delivery, etc. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2538–2543, 2013
Thermoplastic films from plant proteins
Authors: Reddy Narendra , Yang Yiqi 
Published: May 2013

ABSTRACTFilms developed by thermoprocessing of plant proteins have better mechanical properties and are relatively inexpensive and environmentally friendly compared to casting films from solutions. Common plant proteins such as soyproteins, wheat gluten, and corn zein and proteins from lesser grown cereal crops such as peanut, barley, sunflower, and sorghum have all been injection or compression molded into films. Since plant proteins are non‐thermoplastic, it is necessary to chemically or physically modify the proteins and make them thermoplastic. Extensive studies on the addition of plasticizers, pre‐treatment of proteins with alkali, steam, chemical modifications such as acetylation and blending of the proteins with other biopolymers and synthetic polymers have been done to modify proteins and develop thermoplastics. Despite the extensive work, thermoplastic films obtained from plant proteins do not have the properties that can meet or exceed properties of films made from synthetic polymers. Poor water stability and brittleness are the two major limitations of plant protein films. This review presents an overview of the methods and processing conditions used to develop thermoplastic films from plant proteins and the properties of the films. A critical assessment of approaches that have been used so far, limitations of these approaches and potential considerations for future studies to overcome the current limitations have been discussed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 729‐738, 2013
Expanded Scope of the Asymmetric Hydrogenation of Minimally Functionalized Olefins Catalyzed by Iridium Complexes with Phosphite–Thiazoline Ligands
Authors: Mazuela Javier , Pàmies Oscar , Diéguez Montserrat 
Published: May 2013

AbstractWe have replaced the oxazoline group with a thiazoline moiety in one of the most successful of the phosphite–oxazoline ligand families for the Ir‐catalyzed hydrogenation of minimally functionalized olefins. A small but structurally important library of Ir phosphite–thiazoline precatalysts (Ir‐L1–L2 a–e) has been developed by changing the substituents/configurations at the biaryl phosphite group. We found that the replacement of the oxazoline with a thiazoline moiety in the ligand design is beneficial in terms of substrate scope.
Assessment of kinetics, thermodynamics and equilibrium parameters of Cr(VI) biosorption ontoPinus brutiaTen
Authors: Ozdes Duygu , Gundogdu Ali , Kemer Barıs , Duran Celal , Kucuk Murat , Soylak Mustafa 
Published: May 2013

AbstractThe aim of the present study was to investigate the sorption potential of pine bark (Pinus brutiaTen.) for removal of Cr(VI) ions from aqueous solutions. The biosorption characteristics of Cr(VI) ions onto bark biomass were examined with respect to the changes in initial pH of the solution, contact time, initial Cr(VI) and bark concentration, bark particle size, temperature, etc. The biosorption isotherms were described by means of Langmuir and Freundlich models and the biosorption kinetics were analysed using pseudo‐first‐order, pseudo‐second‐order and intraparticle diffusion models. The thermodynamic parameters proved that the process was feasible, spontaneous and endothermic in nature.
Photoluminescence Enhancement of CdSe and CdSe–ZnS Nanocrystals by On‐Surface Ligand Modification
Authors: Oszajca Marek , Lincheneau Christophe , Amelia Matteo , Schäfer Christian , Szaciłowski Konrad , Credi Alberto 
Published: May 2013

AbstractWe have investigated the spectroscopic properties of CdSe and CdSe–ZnS nanocrystal quantum dots (QDs) in the presence of the electron acceptor tetracyanoethene (TCNE) in organic solution. Our results indicate that TCNE reacts with the n‐alkylamine capping ligands at the surfaces of nanocrystals to generate (cyanovinyl)amine products that remain bound to the surfaces of the QDs, substantially increasing their emission efficiency. Further addition of an excess of TCNE caused a decrease in the luminescence intensity, most likely because of an electron‐transfer quenching process from the photoexcited nanocrystals to the electron‐accepting TCNE molecules. TCNE‐induced emission enhancement was also observed for the strongly luminescent CdSe–ZnS core–shell QDs. This approach enables a post‐synthetic adjustment of the luminescence efficiency of amine‐capped QDs. We have also shown that the threshold‐dependent response of the QD emission on the TCNE concentration can be used to encode NAND and XOR Boolean logic operations.
Characterization and emulsifying properties of different sunflower phosphatidylcholine enriched fractions
Authors: Guiotto Estefania N. , Cabezas Dario M. , Diehl Bernd W. K. , Tomás Mabel C. 
Published: May 2013

AbstractFractions enriched in specific phospholipids are desirable for different industrial purposes because of their characteristic physicochemical and functional properties. We studied the fractionation process of sunflower lecithin using different absolute‐ethanol/water ratios and pHs and then evaluated the emulsifying properties of phosphatidyl‐choline‐(PC‐) enriched fractions in oil/water 30:70 v/v emulsions. We observed a high recovery of PC and a low content of phosphatidyl inositol (PI) in all the PC‐enriched fractions thus obtained along with the highest yields of this phospholipid after extraction with an absolute‐ethanol/water mixture of 96:4 v/v. The use of different pH values for the different solvent extraction media did not markedly modify the yield of the enriched fractions. The extraction coefficients for PC and phosphatidyl ethanolamine (PE) evidenced an increase in both these phospholipids in the PC‐enriched fractions upon extraction with the higher concentration of absolute ethanol. Emulsions containing the PC‐enriched fractions obtained with the absolute‐ethanol/water mixture of 96:4 v/v exhibited the highest stability at pH 7.5 because of the high PC/PE ratio compared to that of the PC‐enriched fractions extracted with the absolute‐ethanol/water mixture of 90:10 v/v. A high emulsifier concentration resulted in a low mean D [4,3] diameter of the particles and a high stability.Practical applications: Sunflower lecithin is a promising alternative to soybean lecithin because it is considered the product of a non‐genetically modified organism (non‐GMO). Experimentation on lecithin modification under industrial conditions with adequate techniques of analysis may be useful for evaluating the potential applications of these sunflower by‐products to the production of new emulsifiers. Thus, an analysis of the influence of different fractionation parameters, such as the pH of the solvent extraction, on the composition and emulsifying properties of the resulting PC‐enriched fractions may provide useful information for the food industry.
Influence of free fatty acids on oxidative stability in water‐in‐walnut oil emulsions
Authors: Yi Jianhua , Zhu Zhenbao , Dong Wenbin , McClements David Julian , Decker Eric Andrew 
Published: May 2013

The effect of free fatty acids (FFA) on lipid oxidation in water‐in‐stripped walnut oil emulsions was investigated. The formation of the primary oxidation products (hydroperoxides) and the secondary oxidation product (headspace hexanal) increased with increasing addition of oleic acid to the emulsions. However, oleic acid at high concentrations was primarily involved in accelerating hydroperoxide formation at early stage and then hydroperoxide decomposition rapidly after hydroperoxides reached the maximum point. The prooxidant effect of saturated FFA was dependent on their chain length with lipid oxidation rates being in the order of lauric acid>palmitic acid>stearic acid. The highest prooxidant activity of lauric acid among these FFA was probably due to its largest polarity and making the water droplet interface more negatively charged than the others when the aqueous phase pH was 7.0, which was above its pKa, thereby attracting prooxidant metals to the water droplet surface. The highest ability to promote lipid oxidation in water‐in‐oil emulsions was shown by linolenic acid, followed by linoleic and oleic acids, indicating that the oxidative capacity increased with increasing degree of unsaturation. The prooxidant effect of FFA with the cis double bonds was lower than those with the trans ones when oleic acid (18:1, cis) was compared to elaidic acid (18:1, trans) and linoleic acid (18:2, cis–cis) was compared to linoelaidic acid (18:2, trans–trans), which suggested that geometric isomeration of FFA influenced lipid oxidation rates of water‐in‐oil emulsions.Practical applications: FFA promote lipid oxidation in bulk oil and oil‐in‐water (O/W) emulsions. From the present study, it became clear that FFA were also strong prooxidants in water‐in‐oil (W/O) emulsions. This research pointed out the importance of using oils and fats containing minimal FFA in W/O emulsion formulation to obtain the highest quality.
Concentration of eicosapentaenoic acid (EPA) by selective alcoholysis catalyzed by lipases
Authors: Valverde Lorena Martín , Moreno Pedro A. González , Callejón María José Jiménez , Cerdán Luis Esteban , Medina Alfonso Robles 
Published: May 2013

In this work eicosapentaenoic acid (EPA) enriched acylglycerols were obtained from tuna and sardine oils (9 and 19% weight EPA, respectively) by selective ethanolysis catalyzed by lipases. First, eight immobilized lipases were tested and the best EPA concentration and recovery were attained with lipases QLC® and QLG® from Alcaligenes sp. Lipase QLG® was selected to study the influence of reaction time, temperature and lipase/oil and ethanol/oil ratios. Under the optimized conditions attained (48 h, 20°C, lipase/oil ratio 20% w/w and ethanol/oil molar ratio 2.3:1) and for 59.4% conversion, acylglycerols were obtained with 38.6% EPA and 81.6% recovery from sardine oil. In these optimized conditions the reaction was scaled up to 233 g of sardine oil and carried out in a batch stirred tank reactor, with the lipase contained in a cartridge filter attached to the stirring rod. In this reactor, for 54.8% conversion, acylglycerols were obtained with 35.9% EPA and 82.1% recovery. The EPA‐enriched acylglycerols were separated from the ethyl esters in a short‐path vacuum distiller. At an evaporation temperature of 200°C, a residue with 87.4% acylglycerols (12.6% ethyl esters) was obtained, with an EPA concentration of 33.8 and 64.4% EPA recovery.Practical applications: Marine oils have been shown to have beneficial effects on human health, including positive effects on atherosclerosis, coronary heart disease, inflammatory disease, and perhaps even behavioral disorders. They are attributed to the long‐chain n‐3 polyunsaturated fatty acids, mainly eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). However, it is not clear if both EPA and DHA are equally important in cardiovascular protection, because in most oils both species coexist. In this sense, it is necessary to develop large‐scale purification processes to provide sufficient amounts of oils with high concentrations of both PUFAs on the one hand, and with a high concentration of only one of them on the other. This work studies a method to obtain acylglycerols rich in EPA or in EPA and DHA by selective ethanolysis catalyzed by lipases.
Lipid compositions of latex and sheet rubber from Hevea brasiliensis depend on clonal origin
Authors: Liengprayoon Siriluck , Chaiyut Jatuporn , Sriroth Klanarong , Bonfils Frédéric , Sainte‐Beuve Jérôme , Dubreucq Eric , Vaysse Laurent 
Published: May 2013

Lipids of fresh latex from three Hevea brasiliensis clones (RRIM600, BPM24, and PB235), and of sheet rubber produced from it, were extracted by an optimized method and characterized through various chromatography techniques. Total and free fatty acids, phospholipids, glycolipids, and the unsaponifiable fraction were analyzed for each clone. Qualitative and quantitative comparisons of total extractable lipids indicated a smaller amount in sheet rubber (2.31–3.28% w/w dry rubber) than in fresh latex (3.36–3.67%). Partial hydrolysis during primary rubber processing, such as polar lipids, was found to be the main source of this loss. Alongside the effect of primary processing, the clonal origin of the trees was found to be the main factor for differences in lipid quantity and composition.Practical applications: Lipids are the main non‐isoprene components in natural rubber (NR) and play many important roles in NR properties. Detailed knowledge of the lipid composition would contribute towards a better understanding of the structural and physical properties of NR. The lipid composition also appears to be sufficiently specific to consider its use as a new tool for tracing the clonal origin of NR.
Supramolecular Chemistry of Protoporphyrin IX and Its Derivatives
Authors: Bhosale Sheshanath V. , Bhosale Sidhanath V. , Shitre Ganesh V. , Bobe Sharad R. , Gupta Akhil 
Published: May 2013

AbstractThis microreview surveys developments in applications of protoporphyrin IX (PP‐IX) derivatives in the fields of supramolecular science, artificial photosynthesis and biomedical science. It begins with the introduction of general PP‐IX structure, methods of synthesis and discussion of properties such as solid‐ and liquid‐state interactions. This is followed by description of the compounds' one‐dimensional nano‐superstructures, such as vesicles, tubules, fibres, micellar nanotubes, nanowires, nanorods and coils. Furthermore, a recent advance in protoporphyrin research in the area of monolayer formation is covered. Finally we explore the use of PP‐IX derivatives in energy‐ and electron‐transfer system construction. We conclude with our views on the prospects of PP‐IX for future research endeavours.
Slow release of fragrance aldehydes and ketones in functional perfumery from dynamic mixtures generated with N‐heteroarylmethyl‐substituted secondary diamines
Authors: Trachsel Alain , Chapuis Christian , Herrmann Andreas 
Published: May 2013

ABSTRACTDynamic mixtures of aminals generated by reversible reaction of diamines with volatile aldehydes and ketones are suitable delivery systems to increase the long‐lastingness of fragrance perception in functional perfumery applications. N‐Heteroarylmethyl‐substituted secondary diamines of 1,2‐diaminocyclohexane, 1,3‐diaminocyclohexane, 1,2‐diaminoethane, 1,2‐diaminopropane, 1,3‐diaminopropane or 2‐(aminomethyl)piperidine were prepared by reaction with furan‐, 1H‐pyrrole‐, thiophene‐ or pyridine‐2‐carbaldehyde and reduction of the intermediate imines with NaBH4. The performance of the delivery system was evaluated in a fabric softener application in the presence and absence of a diamine by following the evaporation of a mixture of 18 fragrance aldehydes and ketones on dry cotton using dynamic headspace analysis. Equilibration of the mixture in the presence of a diamine simultaneously increased the headspace concentrations of several fragrance raw materials above the cotton surface as compared to a reference sample without diamine. Equilibrated dynamic mixtures of diamines were found to be suitable delivery systems to prolong the evaporation of fragrance aldehydes and ketones in practical applications of functional perfumery. Copyright © 2013 John Wiley & Sons, Ltd.
Avalanche slope angles in low‐gravity environments from active Martian sand dunes
Authors: Atwood‐Stone Corwin , McEwen Alfred S. 
Published: May 2013

AbstractThe properties of granular material have an important effect on surface landforms and processes. Recently, it has been suggested that material properties called dynamic and static angle of repose vary with gravitational acceleration, which would have a significant effect on many planetary surface processes such as crater collapse and gully formation. In order to test that hypothesis, we measured lee slopes of active aeolian sand dunes on Mars using the High Resolution Imaging Experiment (HiRISE) DTMs (Digital Terrain Model). We examined dune fields in Nili Patera, Herschel Crater, and Gale Crater. Our measurements showed that the dynamic angles of repose for the sands in these areas are 33–34° in the first region and 30–31° in the other two. These results fall within the 30° to 35° window for the dynamic angles of repose for terrestrial dunes with similar flow depths and grain properties and thus show that this angle does not significantly vary with decreasing gravity.
Rapid modeling of the 2011 Mw 9.0 Tohoku‐oki earthquake with seismogeodesy
Authors: Melgar Diego , Crowell Brendan W. , Bock Yehuda , Haase Jennifer S. 
Published: May 2013

AbstractRapid characterization of finite fault geometry and slip for large earthquakes is important for mitigation of seismic and tsunamigenic hazards. Saturation of near‐source weak motion and problematic integration of strong‐motion data into displacements make this difficult in real time. Combining GPS and accelerometer data to estimate seismogeodetic displacement waveforms overcomes these limitations by providing mm‐level three‐dimensional accuracy and improved estimation of coseismic deformation compared to GPS‐only methods. We leverage collocated GPS and accelerometer data from the 2011 Mw 9.0 Tohoku‐oki, Japan earthquake by replaying them in simulated real‐time mode. Using a novel approach to account for fault finiteness, we generate an accurate centroid moment tensor solution independently of any constraint on the slab geometry followed by a finite fault slip model. The replay of GPS and seismic data demonstrates that robust models could have been made available within 3 min of earthquake initiation.
Improving simulations of fine dust surface concentrations over the western United States by optimizing the particle size distribution
Authors: Zhang Li , Kok Jasper F. , Henze Daven K. , Li Qinbin , Zhao Chun 
Published: May 2013

AbstractTo improve estimates of remote contributions of dust to fine particulate matter (PM2.5) in the western United States, new dust particle size distributions (PSDs) based upon scale‐invariant fragmentation theory (Kok_PSD) with constraints from in situ measurements (IMP_PSD) are implemented in a chemical transport model (GEOS‐Chem). Compared to initial simulations, this leads to reductions in the mass of emitted dust particles with radii <1.8 µm by 40%–60%. Consequently, the root‐mean‐square error in simulated fine dust concentrations compared to springtime surface observations in the western United States is reduced by 67%–81%. The ratio of simulated fine to coarse PM mass is also improved, which is not achievable by reductions in total dust emissions. The IMP_PSD best represents the PSD of dust transported from remote sources and reduces modeled PM2.5 concentrations up to 5 µg/m3 over the western United States, which is important when considering sources contributing to nonattainment of air quality standards.
Infrasound reveals transition to oscillatory discharge regime during lava fountaining: Implication for early warning
Authors: Ulivieri Giacomo , Ripepe Maurizio , Marchetti Emanuele 
Published: May 2013

AbstractWe present the analysis of ~4 million infrasonic signals which include 39 episodes of lava fountains recorded at 5.5 km from the active vents. We show that each eruptive episode is characterized by a distinctive trend in the amplitude, waveform, and frequency content of the acoustic signals, reflecting different explosive levels. Lava fountain starts with an ~93 min long violent phase of acoustic transients at ~1.25 Hz repeating every 2–5 s. Infrasound suddenly evolves into a persistent low‐frequency quasi‐monochromatic pressure oscillation at ~0.4 Hz. We interpret this shift as induced by the transition from the slug (discrete Strombolian) to churn flow (sustained lava fountain) regime that is reflecting an increase in the gas discharge rate. We calculate that infrasonic transition can occur at a gas superficial velocity of ≤76 m/s and it can be used to define infrasonic‐based thresholds for an efficient early warning system.
Development of regionalized joint probability approach to flood estimation: a case study for Eastern New South Wales, Australia
Authors: Caballero Wilfredo Llacer , Rahman Ataur 
Published: May 2013

AbstractEstimation of design flood in ungauged catchments is a common problem in hydrology. Methods commonly adopted for this task are limited to peak flow estimation, e.g. index flood, rational and regression‐based methods. To estimate complete design hydrograph, rainfall–runoff modelling is preferred. The currently recommended method in Australia known as Design Event Approach (DEA) has some serious limitations since it ignores the probabilistic nature of principal model inputs (such as temporal patterns (TP) and initial loss) except for design rainfall depth. A more holistic approach such as Joint Probability Approach (JPA)/Monte Carlo Simulation Technique (MCST) can overcome some of the limitations associated with the DEA. Although JPA/MCST has been investigated by many researchers, it has been proved to be difficult to apply since its routine application needs readily available regional design data such as stochastic rainfall duration, TP and losses, which are largely unavailable for Australian states. This paper presents regionalization of the model inputs/parameters to the JPA/MCST for eastern New South Wales (NSW) in Australia. This uses data from 86 pluviograph stations and six catchments from NSW to regionalize the input distributions for application with the JPA/MCST. The independent testing to three test catchments shows that the regionalized JPA/MCST generally outperforms the at‐site DEA. The developed regionalized JPA/MCST can be applied at any arbitrary location in eastern NSW. The method and design data developed here although primarily applicable to eastern NSW can be adapted to other Australian states and countries. Copyright © 2013 John Wiley & Sons, Ltd.