bluuebunny/crossref_metadata_2025_split huggingface dataset:
Urban extent enhances extreme precipitation over the Pearl River Delta, China
Authors: Wang Dagang , Jiang Peng , Wang Guiling , Wang Dashan 
Published: January 2015

AbstractThe relationship between urban extent and extreme precipitation over the Pearl River Delta in China is evaluated using the Tropical Rainfall Measurement Mission 3B42 precipitation product. The spatial pattern of extreme precipitation indices agrees well with that of the urban extent, with significant and positive spatial correlation between the two. The correlation is stronger for extreme indices at shorter temporal scales than for those at longer temporal scales. For example, the coefficient of correlation with the natural logarithm of urban extent is 0.42 for the maximum consecutive 5‐day precipitation amount and reaches 0.74 for the maximum consecutive 3‐h precipitation amount.
Over‐expression of ICE2 stabilizes cytochrome P450 reductase in Saccharomyces cerevisiae and Pichia pastoris
Authors: Emmerstorfer Anita , Wimmer‐Teubenbacher Miriam , Wriessnegger Tamara , Leitner Erich , Müller Monika , Kaluzna Iwona , Schürmann Martin , Mink Daniel , Zellnig Günther , Schwab Helmut , Pichler Harald 
Published: January 2015

AbstractMembrane‐anchored cytochrome P450 enzymes (CYPs) are a versatile and interesting class of enzymes for industrial applications, as they are capable of regio‐ and stereoselectively hydroxylating hydrophobic molecules. However, CYP activity requires sufficient levels of suitable cytochrome P450 reductases (CPRs) for regeneration of catalytic capacity, which is a bottleneck in many industrial applications. Searching for positive effectors of membrane‐anchored CYP/CPR function, we transformed and screened selected strains from a Saccharomyces cerevisiae knockout collection for Hyoscyamus muticus premnaspirodiene oxygenase (HPO; CYP) and Arabidopsis thaliana CPR (AtCPR) expression levels, as well as for activity towards (+)‐valencene. We found that in cells lacking the type III membrane protein Ice2p, AtCPR was destabilized. Remarkably, over‐expression of ICE2 improved (+)‐valencene hydroxylation to trans‐nootkatol by 40–50%, both in resting cells and in vivo. Time‐resolved immunoblot analysis and cytochrome c reductase activity assays revealed that Ice2 up‐regulation stabilized AtCPR levels and activity over extended periods of bioconversion. To underscore that we had identified a novel positive effector of recombinant CYP/CPR function, we confirmed the beneficial effect of ICE2 over‐expression for two further CYP/CPR combinations and the alternative host Pichia pastoris. Thus, we propose Ice2 up‐regulation as a general tool for improving the applications of recombinant CYPs in yeasts.
Crystal and molecular structure of the analgesic tetrapeptide, l‐Phe‐l‐Leu‐l‐Pro‐l‐Ser
Authors: Kaminsky Werner , Stenkamp Ronald E. , Skubatz Hanna 
Published: January 2015

ABSTRACT:The tetrapeptide, l‐Phe‐l‐Leu‐l‐Pro‐l‐Ser (FLPS), alleviates pain in a rat model of post‐surgery pain. The crystal structure of the tetrapeptide is solved at high resolution (0.54 Å). The asymmetric unit contains two FLPS molecules, one Zn ion, and four molecules of water with a formula of [Zn(C23H33N4O6)2(H2O)4]. Each Zn ion is octahedrally coordinated with Phe and Ser residues from four peptide molecules [2N+4O]. The linking of Phe and Ser residues of one FLPS molecule to three other FLPS molecules by Zn ion forms a complex consisting of chains of metal ions and FLPS molecules oriented along the b axis. Analysis of molecular packing reveals the coexistence of two FLPS conformers in the same crystal. The crystallographic parameters for [Zn(C23H33N4O6)2(H2O)4] are as follows: space group P212121, a = 9.8698(2) Å, α = 90°, b = 20.1844(4) Å, β = 90°, c = 25.9302(6) Å, γ = 90°. Volume = 5165.71(19) Å3, Z = 4, density (calc) = 1.364 Mg/cm3, and agreement factor R1 = 4.13%. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 84–90, 2015.
Chromia on Anatase: A Catalyst for Selective Hydrocarbon Combustion in the Presence of CO
Authors: Swislocki Simon , Stöwe Klaus , Maier Wilhelm F. 
Published: January 2015

AbstractThe catalytic activity and selectivity for propane combustion in the presence of CO have been studied with anatase, rutile, eskolaite, chromia‐impregnated anatase, and titania‐impregnated chromia and its physical mixtures. It was found that the selectivity and activity depend on the TiO2 modification. Cr‐doped anatase converts 80 % propane with 100 % selectivity, whereas chromia on rutile converts CO preferentially to propane. Cr10@HOM 500/4 (HOM=Hombikat) and the physical mixture Cr10+HOM 500/4 are promising new catalysts for selective propane oxidation. High‐resolution TEM and powder XRD analyses have shown that a solid solution of chromia in anatase is the active phase of these selective oxidation catalysts. Diffuse reflectance UV/Vis spectroscopy demonstrated the effects of Cr‐doping of TiO2, and Rietveld refinement analysis implied a solid solution of Cr3+ ions in anatase. Evidence for a Mars–van Krevelen mechanism was obtained. Catalyst deactivation was reduced by increasing the oxygen content in the feed. The catalyst is reactivated by treatment with oxygen.
A New Class of Tunable Heterojunction by using Two Support Materials for the Synthesis of Supported Bimetallic Catalysts
Authors: Liao Fenglin , Lo Ben Tsz , Sexton Douglas , Qu Jin , Ma Chensheng , Chan Rath Chau‐Ting , Lu Qin , Che Renchao , Kwok Wai‐Ming , He Heyong , Fairclough Simon , Tsang Shik Chi Edman 
Published: January 2015

AbstractThe front cover artwork for Issue (02/2015) is provided by research groups at the University of Oxford (UK), Hong Kong Polytechnic University (HK, China), USA Naval Research Laboratory (USA), and Fudan University (China). The image depicts a new facile method for producing extremely small supported noble‐metal particles modified with secondary atoms from two support materials. See the Full Paper itself at 10.1002/cctc.201402710.
A copula‐based risk aggregation model
Authors: Côté Marie‐Pier , Genest Christian 
Published: January 2015

AbstractA flexible approach for risk aggregation is considered. The model consists of a tree structure, bivariate copulas, and marginal distributions. The construction relies on a conditional independence assumption whose implications are studied. A procedure for selecting the tree structure is developed using hierarchical clustering techniques, along with a distance metric based on Kendall's tau. Estimation, simulation, and model validation are also discussed. The approach is illustrated using data from a Canadian property and casualty insurance company.The Canadian Journal of Statistics43: 60–81; 2015 © 2015 Statistical Society of Canada
Quality of experience estimation with layered mapping for hypertext transfer protocol video streaming over wireless networks
Authors: Wang Yumei , Sun Mengyao , Wang Kaiyu , Zhang Lin 
Published: January 2015

SummaryHypertext transfer protocol (HTTP) video streaming has occupied more than half of mobile Internet traffic today. Quality of experience (QoE) estimation for HTTP video streaming is significantly meaningful for network operators, as they can utilize valuable network resources more efficiently based on the QoE estimated. But, it is very hard to estimate QoE accurately with theoretical methods. In this paper, we adopt three buffering‐related application metrics, which have been verified to be the main factors that influence the QoE of HTTP videos, together with three fundamental quality of service (QoS) metrics in network layer, to estimate QoE. We suggest a two‐layered mapping model to capture the correlation between network QoS and application QoS and that between application QoS and QoE. Then, we exploit four regression methods, that is, linear regression, back propagation neural network, general regression neural network and support vector regression (SVR), to investigate the mapping relations of the network metrics, the application buffering‐related metrics and QoE. Experimental results demonstrate that general regression neural network and SVR perform almost equally well in fitting ability, and SVR performs best among the four methods in terms of generalization ability. Finally, we analyze the influences of different network QoS parameters on QoE based on the experimental results. Copyright © 2015 John Wiley & Sons, Ltd.
Micro‐RNA‐155‐mediated control of heme oxygenase 1 (HO‐1) is required for restoring adaptively tolerant CD4+ T‐cell function in rodents
Authors: Zhang Jinyu , Vandevenne Patricia , Hamdi Haifa , Van Puyvelde Merry , Zucchi Alessandro , Bettonville Marie , Weatherly Kathleen , Braun Michel Y. 
Published: January 2015

T cells chronically stimulated by a persistent antigen often become dysfunctional and lose effector functions and proliferative capacity. To identify the importance of micro‐RNA‐155 (miR‐155) in this phenomenon, we analyzed mouse miR‐155‐deficient CD4+ T cells in a model where the chronic exposure to a systemic antigen led to T‐cell functional unresponsiveness. We found that miR‐155 was required for restoring function of T cells after programmed death receptor 1 blockade. Heme oxygenase 1 (HO‐1) was identified as a specific target of miR‐155 and inhibition of HO‐1 activity restored the expansion and tissue migration capacity of miR‐155−/− CD4+ T cells. Moreover, miR‐155‐mediated control of HO‐1 expression in CD4+ T cells was shown to sustain in vivo antigen‐specific expansion and IL‐2 production. Thus, our data identify HO‐1 regulation as a mechanism by which miR‐155 promotes T‐cell‐driven inflammation.
Synthesis, Structures and Thermal Decomposition of Monomeric Aluminium, Gallium and Indium Silylphosphanides
Authors: Kapitein Manuel , von Hänisch Carsten 
Published: January 2015

AbstractMonomeric N‐heterocyclic carbene (NHC)‐stabilized compounds (IMes)R2MP(H)SitBuPh2 (2: M = Al, R = Et; 3: M = Ga, R = Et; 4: M = Ga, R = iPr; 5: M = In, R = Et) have been prepared in moderate yields through the cleavage of four‐membered metal phosphine rings like [iPr2GaP(H)SitBuPh2]2 (1) described herein. These compounds were isolated and characterized by means of X‐ray crystallographic analysis as well as NMR spectroscopy. On this basis the structural properties, specifically the M–P bond lengths and CNHC–M–P angles, are discussed and compared to literature‐known compounds insofar as possible. Proceeding from the cis setting between the phosphorus‐bound hydrogen and the metal‐bound organic substituent with very low torsion angles, which result in a nearly coplanar arrangement, the results of thermally induced elimination reactions are described. Further, the resulting heterocubane structures 6 and 7 are described.
The Nature of Hydrogen Production from Aqueous‐Phase Methanol Dehydrogenation with Ruthenium Pincer Complexes Under Mild Conditions
Authors: Lei Ming , Pan Yuhui , Ma Xuelu 
Published: January 2015

AbstractA density functional theory (DFT) study was performed to unveil the nature of dihydrogen (H2) production from aqueous‐phase methanol dehydrogenation catalyzed by a ruthenium pincer complex. Three catalytic cycles of methanol, formaldehyde, and formate dehydrogenations were investigated at the ωB97X‐D/BSI level. The calculated results indicate that the methanol‐assisted hydrogen‐release step is much more favorable than the direct hydrogen‐release one. The dehydrogenation step, the methanol‐assisted hydrogen‐release step, and the CO2‐release step are the rate‐determining steps of methanol, formaldehyde, and formate dehydrogenations (stage I, stage II, and stage III), respectively. In addition, the formate dehydrogenation is proposed to be more difficult than the methanol and formaldehyde dehydrogenations according to calculated free‐energy profiles. Methanol and formaldehyde dehydrogenation likely follow an outer‐sphere mechanism, but formate dehydrogenation could involve both outer‐sphere and inner‐sphere mechanisms. These results add to our fundamental understanding of this efficient hydrogen‐generation reaction from methanol, which could be helpful in the implementation of the methanol/hydrogen economy.
A Fivefold Interpenetrating dmd Topological Copper(I) Cyanide Complex Formed by C–C Bond Cleavage of Acetonitrile
Authors: Li Lin , Wang Chun‐Hai , Zhang Xia‐Li , Liu Xi 
Published: January 2015

AbstractThe solvothermal reaction of a mixture of copper nitrate and 3,5‐bis(4‐pyridyl)‐1H‐1,2,4‐triazole (4,4′‐Hbpt) in a mixed acetonitrile/water solvent leads to a special copper(I) cyanide complex Cu3(CN)3(4,4′‐Hbpt)2 (1) with a fivefold interpenetrating dmd topological framework. The cyanide ligands in the structure are generated in situ from the C–C cleavage of acetonitrile under solvothermal conditions. Solid‐state luminescence experiments show that 1 can emit efficient violet luminescence, and the possible emission mechanism was investigated in detail through theoretical calculations. The results may be helpful for the design and synthesis of efficient luminescent materials.
Homoleptic and Heteroleptic Ruthenium(II) Complexes Based on 2,6‐Bis(quinolin‐2‐yl)pyridine Ligands – Multiple‐Charged‐State Modules for Potential Density Memory Storage
Authors: Marin Ion , Turta Constantin , Benniston Andrew C. , Harrington Ross W. , Clegg William 
Published: January 2015

AbstractThe two ligands 2,6‐bis(4‐methylquinolin‐2‐yl)pyridine (L1) and diethyl 2,2′‐(pyridine‐2,6‐diyl)bis(quinolone‐4‐carboxylate) (L2) were used to prepare the homoleptic [Ru(L2)2][PF6]2 (RU1) and heteroleptic [Ru(L1)(L2)][PF6]2 (RU2) complexes. DFT calculations (B3PW91,3‐21G**) performed on both RU1 and RU2 revealed that redox at the ruthenium site for RU2 is less positive by ca. 110 mV. Consequently, the one‐electron ligand‐based reduction for RU2 is more cathodic by 80 mV. Electrochemistry experiments confirmed that the prediction is qualitatively correct and that the complexes can each hold up to five electrons reversibly.
Ionic liquid‐assisted subcritical water promotes the extraction of lipids from wet microalgae Scenedesmus sp
Authors: Chen Xiaolin , Hu Linfeng , Xing Ronge , Liu Song , Yu Huahua , Qin Yukun , Li Kecheng , Li Rongfeng , Li Pengcheng 
Published: January 2015

Presently, microalgae are considered one of the most promising feedstocks. However, a large scale and efficient extraction method is costly to implement. Therefore, in this paper, we examine the use of an environmentally friendly solvent‐ionic liquid‐assisted subcritical water method to extract lipids from wet Scenedesmus sp. The extraction efficiency under various experimental conditions was evaluated. The optimal experimental parameters consisted of the ionic liquid species [HNEt3][HSO4], a 1% concentration of ionic liquid species‐ [HNEt3][HSO4], and a temperature of 110°C. The lipid yield under the optimal conditions (35.67% dried weight biomass) was close to that of the Bligh & Dyer method (35.32% dried weight biomass). However, the triacylglycerol content (73.63% total lipids) was higher than that of the Bligh & Dyer's method (60.44% total lipids). In addition, algae cell residues assembled into microspheres, therefore, they were easy to separate from the mixture.Practical applications: This method allows for easy and efficient extraction of lipids from wet microalgae, and it is environmentally friendly and easy to scale up. Therefore, it may prove beneficial for biodiesel production.A new, environmentally friendly method of extracting lipids from the wet Scenedesmus sp. is described, in which the effect of various experimental parameters including ionic liquid species, the concentration of ionic liquids, and temperature on the extraction efficiency were evaluated. By this method, lipids can be extracted from wet microalgae easily and efficiently. The lipid yield under the optimal conditions was close to the extraction result of Bligh & Dyer's method and the TAG concentration was higher than that of the Bligh & Dyer's method. Analysis of the fatty acid composition showed that the extracted lipids were a good source of crude oil for future biodiesel production.
Improving oxidative stability of peanut oil under microwave treatment and deep fat frying by stearic acid–surfacant–tea polyphenols complex
Authors: Shi Rong , Guo Yi , Vriesekoop Frank , Yuan Qipeng , Zhao Shuna , Liang Hao 
Published: January 2015

In this work we present a study of the influence of a stearic acid–surfactant–tea polyphenols complex (SSTC) on the oxidative and thermal stability of peanut oil under microwave heating and simulated deep fat frying. Changes of the quality parameters of all oil samples containing different SSTCs were very obvious, compared with those of pure peanut oil. Especially for the oil sample containing SSTC‐P, the p‐anisidine value decreased 48.89% and 14.90% after microwave heating and simulated deep fat frying. For K232, it decreased 36.90% and 33.18%, respectively. By GS–MS analysis, the content of unsaturated fatty acids in peanut oil containing SSTC‐P was 8.7 times more than that in pure peanut oil after microwave treatment. As an efficient food antioxidant, the self‐assembled complex of tea polyphenols in edible oil prepared by this novel method may have great market potential.Practical applications: Oxidation processes are one of the major problems encountered in oil consumption and storage. The addition of natural antioxidants is a major way to inhibit oxidation processes in edible oils. Tea polyphenols are excellent source of phenolic compounds, which have been reported to show good antioxidant activity. The results of this study suggest that oil‐soluble tea polyphenols can be prepared based on a stearic acid–surfactant–tea polyphenols complex. The dispersion of SSTC into peanut oil can improve oxidative and thermal stability of edible oil. Therefore, the complex of tea polyphenols in edible oil may have great market potential of food antioxidant.Tea polyphenols solution was used as the aqueous phase. Stearic acid containing appropriate amount of surfactant were poured into a 50 mL centrifuge tube, and kept in a water bath maintained at 80°C and stirred at 500 rpm until a homogeneous clear solution was obtained. Then, the aqueous phase and the oil phase were mixed using a homogenizer at 26 000 rpm for 2 min to form a stable W/O emulsion. The resulting emulsion was frozen rapidly in liquid nitrogen, and lyophilized using a freeze‐drying machine for 48 h. Finally, all of the stearic acid–surfactant–tea polyphenols complexes (SSTC) were obtained. The SSTC was dispersed in peanut oil. Oxidation products of the oil sample were analyzed by GC–MS under microwave heating.
Monitoring the oxidative stability and volatiles in blanched, roasted and fried almonds under normal and accelerated storage conditions by DSC, thermogravimetric analysis and ATR‐FTIR
Authors: Valdés Arantzazu , Beltrán Ana , Karabagias Ioannis , Badeka Anastasia , Kontominas Michael G. , Garrigós María Carmen 
Published: January 2015

In this study, the effect of different cooking processes (blanching, roasting and frying) on the oxidative stability of almonds under normal storage and accelerated oxidation conditions were investigated. Fried almonds showed higher initial linoleic acid content due to oil frying medium migration to the samples. As oxidation time increased, a different trend in fatty acid composition was obtained depending on the oxidation conditions used. Samples processed at high temperatures presented an initial high PV, resulting in an advanced state of oxidation. A simultaneous formation of hydroperoxides and secondary oxidation compounds was observed in samples under normal storage, presenting raw samples of the lower PV and AV. Lower values of thermal parameters (DSC and TGA) were obtained with increasing oxidation time at 100°C. The most abundant volatile compounds (HS‐SPME‐GC‐MS) present in raw almonds were benzaldehyde, 1,3‐dimethyl‐benzene, 1,2‐dimethyl‐benzene, styrene, 3‐methyl‐1‐butanol, alpha‐pinene and limonene; whereas roasted almonds showed Maillard reaction volatiles such as pyrazines, pyrroles and furans; and fried almonds showed compounds derived from frying oil decomposition (trans,cis‐2,4‐decadienal and trans,trans‐2,4‐decadienal) and higher amounts of aldehydes (hexanal, octanal and nonanal). The generation of hydroperoxides, their degradation and the formation of secondary oxidation products were also investigated by FTIR analysis.Practical applications: Processing of almonds at high temperatures may result in quality deterioration, leading to oxidative rancidity. The studied techniques used in this paper can be useful for processors in order to monitor the oxidative degradation of nuts with storage time and to evaluate their acceptance on the market. In particular, the use of DSC, TGA and ATR‐FTIR could be suitable for studying the shelf life of processed almonds and saving time, which is very precious in quality control.The effect of different cooking processes (blanching, roasting and frying) on the oxidative stability of almonds under normal storage and accelerated oxidation conditions were investigated. Fatty acid composition, primary and secondary oxidation products, thermal parameters, volatiles and lipid degradation were assessed. Results indicate that processing and technological strategies should be used for almond production in order to obtain better oxidative stability and to assure preservation of their overall nutritional profile.
Lipophilization of phenolic acids with phytosterols by a chemoenzymatic method to improve their antioxidant activities
Authors: Wang Zhiqiang , Hwang Seung Hwan , Lim Soon Sung 
Published: January 2015

In this study, a two‐step method for chemoenzymatic lipophilization of phenolic acids with phytosterols was studied. Optimal conditions for esterification involved the use of a binary solvent containing hexane and 2‐butanone (3 mL, 8:2, v/v), a relatively equal molar ratio of vinyl ester to phytosterols (0.1 mmol), and 100 U/mL of lipase from Candida rugosa at 55°C. Various phenolic acids were used, but only ten of them were successes. Their antioxidant activities were evaluated by total oxidation (TOTOX) value and thiobarbituric acid reactive substances (TBARS) value. Phytosteryl 4‐hydroxybenzoate, phytosteryl vanillate, and phytosteryl ferulate showed potential for use as food antioxidants.Practical applications: There is increasing interest in the development of antioxidants from natural sources because of the concerns about the safety of synthetic antioxidants. Lipophilization of phenolic acids was carried out to improve the hydrophobicity and change the antioxidant capacity of phenols. This study focuses on phytosterol, which is a food‐grade mixture of steroid compounds, having development and application potential as a cost effective food additive. According to our results, phytosteryl phenolates, which are defined as esters between phytosterols and phenolic acids, have the potential for use as alternative food antioxidants in the food industry.The lipophilization of phenolic acids with phytosterols was carried out via a two‐step chemoenzymatic route as the figure showed. The intermediate vinyl esters were first chemically produced and subsequently esterified with phytosterols catalyzed by lipase from Candida rugosa.