bluuebunny/crossref_metadata_2025_split huggingface dataset:
An improved methodology for deriving high‐resolution surface shortwave radiative fluxes from MODIS in the Arctic region
Authors: Niu Xiaolei , Pinker Rachel T. 
Published: February 2015

AbstractThe Arctic is experiencing an unprecedented increase in surface air temperature and decrease in sea ice extent. The causes of these changes are still being debated; radiative fluxes are believed to play an important role in this warming. The primary motivation for this study is to advance the quality and resolution of currently available information on surface shortwave (solar) irradiance (SWR) for the Arctic. Such information is needed to meet the challenge for accurate estimates of heat input into the open waters. An inference scheme that utilizes the Moderate Resolution Imaging Spectroradiometer (MODIS) observations is optimized for high latitudes and implemented at 5 km for 2007 at an hourly time scale. Evaluation of the 5 km based SWR estimates against hourly ground observations at Barrow site shows a mean bias of 7.9 W m−2 (3% of mean values), a standard deviation of 58.2 W m−2 (23% of mean value), and a high correlation of 0.95. Evaluation of the SWR estimates against daily ground measurements at these latitudes shows good agreement with surface observations at three sites, with a mean bias of 1.9 W m−2 (1.1% of mean values), a standard deviation of 31.5 W m−2 (17.8% of mean value), and a high correlation of 0.96. Information at this high resolution and good quality can lead to improved estimates of heat input into the complex Arctic domain. For the Beaufort Sea domain (70°N–80°N, 120°E–50°E), the differences can amount to 116 MJ m−2 (~7%) of the total solar input of this region.
Atmospheric water vapor retrieval from Landsat 8 thermal infrared images
Authors: Ren Huazhong , Du Chen , Liu Rongyuan , Qin Qiming , Yan Guangjian , Li Zhao‐Liang , Meng Jinjie 
Published: February 2015

AbstractAtmospheric water vapor (wv) is required for the accurate retrieval of the land surface temperature from remote sensing data and other applications. This work aims to estimate wv from Landsat 8 Thermal InfraRed Sensor (TIRS) images using a new modified split‐window covariance‐variance ratio (MSWCVR) method on the basis of the brightness temperatures of two thermal infrared bands. Results show that the MSWCVR method can theoretically retrieve wv with an accuracy better than 0.3 g/cm2 for dry atmosphere (wv <2 g/cm2) conditions and better than 0.5 g/cm2 for wet atmosphere conditions. The method was applied at different locations with dry and moist atmospheres and was validated at 42 ground sites using AERONET (Aerosol Robotic Network) ground‐measured data and MODIS (Moderate Resolution Imaging Spectroradiometer) products. The results show that the retrieved wv from the TIRS data is highly correlated with the wv of AERONET and MODIS but is generally larger. This difference was probably attributed to the uncertainty of radiometric calibration and stray light coming outside from field of view of TIRS instrument in the current images. Consequently, the data quality and radiometric calibration of the TIRS data should be improved in the future.
Chemical variations in Yellowknife Bay formation sedimentary rocks analyzed by ChemCam on board the Curiosity rover on Mars
Authors: Mangold N. , Forni O. , Dromart G. , Stack K. , Wiens R. C. , Gasnault O. , Sumner D. Y. , Nachon M. , Meslin P.‐Y. , Anderson R. B. , Barraclough B. , Bell J. F. , Berger G. , Blaney D. L. , Bridges J. C. , Calef F. , Clark B. , Clegg S. M. , Cousin A. , Edgar L. , Edgett K. , Ehlmann B. , Fabre C. , Fisk M. , Grotzinger J. , Gupta S. , Herkenhoff K. E. , Hurowitz J. , Johnson J. R. , Kah L. C. , Lanza N. , Lasue J. , Le Mouélic S. , Léveillé R. , Lewin E. , Malin M. , McLennan S. , Maurice S. , Melikechi N. , Mezzacappa A. , Milliken R. , Newsom H. , Ollila A. , Rowland S. K. , Sautter V. , Schmidt M. , Schröder S. , d'Uston C. , Vaniman D. , Williams R. 
Published: February 2015

AbstractThe Yellowknife Bay formation represents a ~5 m thick stratigraphic section of lithified fluvial and lacustrine sediments analyzed by the Curiosity rover in Gale crater, Mars. Previous works have mainly focused on the mudstones that were drilled by the rover at two locations. The present study focuses on the sedimentary rocks stratigraphically above the mudstones by studying their chemical variations in parallel with rock textures. Results show that differences in composition correlate with textures and both manifest subtle but significant variations through the stratigraphic column. Though the chemistry of the sediments does not vary much in the lower part of the stratigraphy, the variations in alkali elements indicate variations in the source material and/or physical sorting, as shown by the identification of alkali feldspars. The sandstones contain similar relative proportions of hydrogen to the mudstones below, suggesting the presence of hydrous minerals that may have contributed to their cementation. Slight variations in magnesium correlate with changes in textures suggesting that diagenesis through cementation and dissolution modified the initial rock composition and texture simultaneously. The upper part of the stratigraphy (~1 m thick) displays rocks with different compositions suggesting a strong change in the depositional system. The presence of float rocks with similar compositions found along the rover traverse suggests that some of these outcrops extend further away in the nearby hummocky plains.
Uncertainty quantification for a climatology of the frequency and spatial distribution of North Atlantic tropical cyclone landfalls
Authors: Tolwinski‐Ward S. E. 
Published: February 2015

AbstractA spatially resolved climatology for the annual frequency of tropical cyclone (TC) landfalls along the Atlantic coast of North America is developed, and its uncertainty deriving from multiple sources is quantified. Historical landfall counts in piecewise‐linear segments approximating the coastline are modeled using Poisson regression with spatial random effects. Predictors include index representations of the mean hurricane‐season phases of the Southern Oscillation, the Atlantic Multidecadal Oscillation, and the North Atlantic Oscillation, with the effect of the latter also modeled spatially. This spatial generalized linear model for landfall frequency is used in conjunction with a data level accounting explicitly for the time‐dependent uncertainty in the recorded landfall positions. The model performs skillfully in cross‐validation exercises. The inferred effects of the climatic predictors are also consistent with current scientific understanding of the mechanisms through which related large‐scale climatic variability affects the development and motion of Atlantic tropical cyclones. Sampling variability in the data over the short length of the observational record and observational error in the historical data are found to contribute substantially to the overall climatological uncertainty. The contribution from uncertainty in the underlying model parameters is negligible compared to these other sources. The model presented here could be used for applications in insurance and risk management, and adaptations could also be used to investigate changes in TC landfall climatology under an uncertain and changing climate.
The tilt of mean sea level along the east coast of North America
Authors: Higginson S. , Thompson K. R. , Woodworth P. L. , Hughes C. W. 
Published: February 2015

AbstractThe tilt of mean sea level along the North American east coast has been a subject of debate for many decades. Improvements in geoid and ocean circulation models, and GPS positioning of tide gauge benchmarks, provide an opportunity to produce new tilt estimates. Tilts estimated using tide gauge measurements referenced to high‐resolution geoid models (the geodetic approach) and ocean circulation models (the ocean approach) are compared. The geodetic estimates are broadly similar, with tilts downward to the north through the Florida Straits and at Cape Hatteras. Estimates from the ocean approach show good agreement with the geodetic estimates, indicating a convergence of the two approaches and resolving the long standing debate as to the sign of the tilt. These tilts differ from those used by Yin and Goddard (2013) to support a link between changing ocean circulation and coastal sea level rise.
Heterogeneous Gold‐Catalyzed Selective Reductive Transformation of Quinolines with Formic Acid
Authors: Tao Lei , Zhang Qi , Li Shu‐Shuang , Liu Xiang , Liu Yong‐Mei , Cao Yong 
Published: February 2015

AbstractSingle phase rutile titania supported gold nanoparticles (Au/TiO2‐R) are found to be efficient and versatile catalysts for chemo‐ and regioselective transfer hydrogenation of quinoline derivatives to 1,2,3,4‐tetrahydroquinolines (THQs) using formic acid (FA) as a safe and convenient hydrogen source under mild conditions. The activity and chemoselectivity of the Au/TiO2‐R catalyst towards THQs is excellent, with a substrate to catalyst ratio (S/C) of 1000 being feasible. Furthermore, a straightforward and selective route to N‐formyltetrahydroquinolines (FTHQ) directly from quinoline compounds and FA by one‐pot, gold‐catalyzed reductive N‐formylation protocol is also established.magnified image
Examining the Influence of Production Scale on the Volume Expansion Behavior of Polyethylene Foams in Rotational Foam Molding
Authors: Emami Maryam , Vlachopoulos John , Thompson Michael R. , Maziers Eric 
Published: February 2015

ABSTRACTIn the present study, an evaluation of the “scale of production” on rotational foam molding was conducted and experimental observations from microscopic, lab‐ and pilot‐scale foam systems were used to investigate the impact of the rheology on the process. A systematic comparison looking at the influence of rheological properties of the polymer matrix on the expansion behavior of polyethylene foams indicated that the size of the foam system does not affect the fundamental mechanisms of the foaming process and that the effects of system size on foam techniques could be suppressed by tailoring the processing conditions. It was demonstrated that the impact of rheology on bubble development observed in microscopic studies can be practically extended to higher scales of foaming, and the results can provide guidelines for the selection of the polymer materials for customized foam applications.
A Metal–Ligand Cooperative Pathway for Intermolecular Oxa‐Michael Additions to Unsaturated Nitriles
Authors: Perdriau Sébastien , Zijlstra Douwe S. , Heeres Hero J. , de Vries Johannes G. , Otten Edwin 
Published: February 2015

AbstractAn unprecedented catalytic pathway for oxa‐Michael addition reactions of alcohols to unsaturated nitriles has been revealed using a PNN pincer ruthenium catalyst with a dearomatized pyridine backbone. The isolation of a catalytically competent Ru–dieneamido complex from the reaction between the Ru catalyst and pentenenitrile in combination with DFT calculations supports a mechanism in which activation of the nitrile through metal–ligand cooperativity is a key step. The nitrile‐derived Ru‐N moiety is sufficiently Brønsted basic to activate the alcohol and initiate conjugate addition of the alkoxide to the α,β‐unsaturated fragment. This reaction proceeds in a concerted manner and involves a six‐membered transition state. These features allow the reaction to proceed at ambient temperature in the absence of external base.
Electron Transfer in Peptides: On the Formation of Silver Nanoparticles
Authors: Kracht Sonja , Messerer Matthias , Lang Matthieu , Eckhardt Sonja , Lauz Miriam , Grobéty Bernard , Fromm Katharina M. , Giese Bernd 
Published: February 2015

AbstractSome microorganisms perform anaerobic mineral respiration by reducing metal ions to metal nanoparticles, using peptide aggregates as medium for electron transfer (ET). Such a reaction type is investigated here with model peptides and silver as the metal. Surprisingly, Ag+ ions bound by peptides with histidine as the Ag+‐binding amino acid and tyrosine as photoinducible electron donor cannot be reduced to Ag nanoparticles (AgNPs) under ET conditions because the peptide prevents the aggregation of Ag atoms to form AgNPs. Only in the presence of chloride ions, which generate AgCl microcrystals in the peptide matrix, does the synthesis of AgNPs occur. The reaction starts with the formation of 100 nm Ag@AgCl/peptide nanocomposites which are cleaved into 15 nm AgNPs. This defined transformation from large nanoparticles into small ones is in contrast to the usually observed Ostwald ripening processes and can be followed in detail by studying time‐resolved UV/Vis spectra which exhibit an isosbestic point.
Organic Donor Materials Based on Bis(arylene ethynylene)s for Bulk Heterojunction Organic Solar Cells with High Voc Values
Authors: Zhan Hongmei , Liu Qian , Dai Fengrong , Ho Cheuk‐Lam , Fu Yingying , Li Leijiao , Zhao Li , Li Hua , Xie Zhiyuan , Wong Wai‐Yeung 
Published: February 2015

AbstractA series of purely organic small molecules 1–4 based on bis(arylene ethynylene)s with various electron‐rich aromatic bridges, such as benzene, cyclopentadithiophene (CDT), and diphenyl(p‐tolyl)amine, were synthesized by a Sonogashira coupling reaction. Their optical, electronic, and electrochemical properties were fully characterized. The photovoltaic properties of these molecules as donor materials and [6,6]‐phenyl‐C71‐butyric acid methyl ester as an acceptor material in solution‐processed bulk heterojunction devices were studied. Among them, CDT‐bridged molecule 2 exhibited the best photovoltaic performance and achieved a power conversion efficiency of 3.28 %. In addition, the photovoltaic efficiencies of these molecules are higher than their corresponding platinum‐containing counterparts, probably owing to their stronger light absorption and improved open‐circuit voltage.
A H+/Ag+ Dual‐Target Responsive Label‐Free Light‐Up Probe Based on a DNA Triplex
Authors: Xu Lijun , Guo Yahui , Wang Jine , Zhou Lu , Zhang Yuanyuan , Hong Shanni , Wang Zhili , Zhang Jianye , Pei Renjun 
Published: February 2015

AbstractWe developed a dual‐target responsive sensor for label‐free light‐up fluorescent detection of protons (H+) and silver ions (Ag+) using an “OR′′ logic gate. Berberine, a cost‐effective and non‐toxic indicator, partially intercalates the formed triplex DNA in the presence of H+ or Ag+, generating enhanced fluorescence. The designed Ag+ probe has high selectivity and desirable sensitivity, which is necessary for practical use. The robust ”OR“ logic gate is capable of a rapid and reversible response to the H+ and/or Ag+ inputs.
Maternal risk for down syndrome and polymorphisms in the promoter region of the DNMT3B gene: A case–control study
Authors: Jaiswal Sushil Kumar , Sukla Krishna Kishore , Kumari Neha , Lakhotia Anjali Rani , Kumar Ashok , Rai Amit Kumar 
Published: February 2015

BackgroundEpigenetic changes leading to improper methylation of the pericentromeric region of chromosome 21 may contribute to the nondisjunction of this chromosome. Polymorphisms in the DNA Methyltransferase 3B (DNMT3B) gene, one of the crucial gene of the folate metabolism, affects the activity of the enzyme and increases the susceptibility of nondisjunction in mothers of Down syndrome children (MDS).MethodsConsidering this hypothesis we investigated the association of single nucleotide polymorphisms in the promoter region of the DNMT3B gene (rs1569686 ‐579G>T; rs2424913 ‐149C>T) with a predisposition of mothers to deliver a Down syndrome (DS) child. The study was performed on DNA samples from 150 MDS and 172 control mothers. Transmission disequilibrium tests were performed on 103 DS trio families. Genotyping was done using a polymerase chain reaction‐restriction fragment length polymorphism method.ResultsWith respect to the single nucleotide polymorphisms studied, no significant difference was observed in the genotypes and alleles frequency distributions between MDS and control mothers. The frequency of the DNMT3B‐579G allele was, respectively, 0.34 in MDS and 0.33 in control mothers whereas the frequency of the DNMT3B‐149C allele was respectively 0.31 in MDS and 0.26 in control mothers. No significant deviation in genotypic combinations as well as in transmission disequilibrium tests analysis was observed. However, a strong linkage disequilibrium was observed with significant differences in the distribution of G‐T and G‐C haplotypes among case and control mothers.ConclusionAlthough the above studied polymorphisms of DNMT3B may not be an independent risk factor it might be possible that certain allelic combinations (G‐T) are. This finding suggests that DNMT3B might be a maternal risk factor for DS in our Indian cohort. Replication studies are required to confirm these findings. Birth Defects Research (Part A) 103:299–305, 2015. © 2015 Wiley Periodicals, Inc.
Photoluminescence properties of LiBaPO4:M3+ phosphor for near‐UV light‐emitting diode (M = Eu and Dy)
Authors: Puppalwar S. P. , Dhoble S. J. 
Published: February 2015

AbstractA novel phosphor LiBaPO4 doped with rare earths Eu and Dy prepared by high temperature solid‐state reaction method is reported. The phosphors were characterized by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL). The emission and excitation spectra of these materials were measured at room temperature with a spectrofluorophotometer. The excitation spectra of LiBaPO4:Eu3+ phosphor can be efficiently excited by 394 nm, which is matched well with the emission wavelength of near‐UV light‐emitting diode (LED) chip. PL properties of Eu3+‐doped LiBaPO4 exhibited the characteristic red emission coming from 5D0 → 7 F1 (593 nm) and 5D0 → 7 F2 (617 nm) electronic transitions with color co‐ordinations of (0.680, 0.315). The results demonstrated that LiBaPO4:Eu3+ is a potential red‐emitting phosphor for near‐UV LEDs. Emission spectra of LiBaPO4:Dy3+ phosphors showed efficient blue (481 nm) and yellow (574 nm) bands, which originated from 4 F9/2 → 6H15/2 and 4 F9/2 → 6H13/2 transitions of the Dy3+ ion, respectively. The 574 nm line is more intense than the 481 nm lines, which indicates that the site Dy3+ is located with low symmetry. This article summarizes fundamentals and possible applications of optically useful inorganic phosphates with visible photoluminescence of Eu3+ and Dy3+ ions. Copyright © 2015 John Wiley & Sons, Ltd.
The role of proline‐containing peptide triads in β‐sheet formation: A kinetic study
Authors: Takor Gaius A. , Higashiya Seiichiro , Sikirzhytski Vitali K. , Seeley Jason P. , Lednev Igor K. , Welch John T. 
Published: February 2015

ABSTRACTThe design of biomimetic materials through molecular self‐assembly is a growing area of modern nanotechnology. With problems of protein folding, self‐assembly, and sequence–structure relationships as essential in nanotechnology as in biology, the effect of the nucleation of β‐hairpin formation by proline on the folding process has been investigated in model studies. Previously such studies were limited to investigations of the influence of proline on the formation of turns in short peptide sequences. The effect of proline‐based triads on the folding of an 11‐kDa amyloidogenic peptide GH6[(GA)3GY(GA)3GE]8GAH6 (YE8) was investigated by selective substitution of the proline‐substituted triads at the γ‐turn sites. The folding and fibrillation of the singly proline‐substituted polypeptides, e.g., GH6[(GA)3GY(GA)3GE]7(GA)3GY(GA)3PDGAH6 (8PD), and doubly proline‐substituted polypeptides, e.g., GH6[(GA)3GY(GA)3GE]3(GA)3GY(GA)3PD[(GA)3GY(GA)3GE]3(GA)3GY(GA)3PDGAH6 (4,8PD), were directly monitored by circular dichroism and deep UV resonance Raman and fluorescence spectroscopies. These findings were used to identify the essential folding domains, i.e., the minimum number of β‐strands necessary for stable folding. These experimental findings may be especially useful in the design and construction of peptidic materials for a wide range of applications as well as in understanding the mechanisms of folding critical to fibril formation. © 2015 Wiley Periodicals, Inc. Biopolymers 103: 339–350, 2015.
Exploring students' learning attitude and achievement in flipped learning supported computer aided design curriculum: A study in high school engineering education
Authors: Chao Chih‐Yang , Chen Yuan‐Tai , Chuang Kuei‐Yu 
Published: February 2015

ABSTRACTThis research aims to explore the benefits of a flipped learning approach for students who are taking an introductory‐level curriculum on bridge computer aided design in terms of learning attitude and achievement within the curriculum. In this study, collaborative problem based learning (CPBL) supported by flipped learning, a blended learning design, was integrated into a high school bridge computer aided design curriculum. Ninety‐one 17‐year‐old students from two K11 classes were assigned randomly to an experimental group and a control group for the study, respectively. To assess the students' achievements and learning attitudes in the different groups, an 8‐week (16 h in total) pre‐ and post‐test quasi‐experimental study was designed. The results confirmed the effectiveness of the flipped learning approach. Significant differences were found between the experimental and control group in terms of students' achievements. In the experimental group, students' learning attitudes, motivation and self‐evaluation were enhanced. In conclusion, the results show that the flipped learning approach has a positive effect on the transfer of learning. Based on the findings obtained, recommendations for the improvement of future K12 engineering education instruction using the flipped learning approach are provided. © 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:514–526, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21622