bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating the impact of haze on MODIS cloud detection
Authors: Mao Feiyue , Duan Miaomiao , Min Qilong , Gong Wei , Pan Zengxin , Liu Guangyi 
Published: November 2015

AbstractThe cloud detection algorithm for passive sensors is usually based on a fuzzy logic system with thresholds determined from previous observations. In recent years, haze and high aerosol concentrations with high aerosol optical depth (AOD) occur frequently in China and may critically impact the accuracy of the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud detection. Thus, we comprehensively explore this impact by comparing the results from MODIS/Aqua (passive sensor), Cloud‐Aerosol Lidar with Orthogonal Polarization/CALIPSO (lidar sensor), and Cloud Profiling Radar/CloudSat (microwave sensor) of the A‐Train suite of instruments using an averaged AOD as an index for an aerosol concentration value. Case studies concerning the comparison of the three sensors indicate that MODIS cloud detection is reduced during haze events. In addition, statistical studies show that an increase in AOD creates an increase in the percentage of uncertain flags and a decrease in hit rate, a consistency index between consecutive sets of cloud retrievals. On average, AOD values lower than 0.1 give hit rate values up to 80.0% and uncertainty values lower than 16.8%, while AOD values greater than 1.0 reduce the hit rate below to 66.6% and increase the percentage of uncertain flags up to 46.6%. Therefore, we can conclude that the ability of MODIS cloud detection is weakened by large concentrations of aerosols. This suggests that use of the MODIS cloud mask, and derived higher‐level products, in situations with haze requires caution. Further improvement of this retrieval algorithm is desired as haze studies based on MODIS products are of great interest in a number of related fields.
The formation of viscous limited saturation zones behind rapid drainage fronts in porous media
Authors: Hoogland Frouke , Lehmann Peter , Or Dani 
Published: November 2015

AbstractDrainage characteristics of porous media are shaped by an interplay between gravitational, capillary and viscous forces that result in complex phase invasion patterns and dynamics. We propose a mechanistic model for viscous separation of temporary phase detention behind rapidly moving drainage fronts. The viscous‐limited region forming behind the front tip (tip of furthest penetrated air finger) drains at a slower rate with a characteristic time scale τ dictated by hydraulic decoupling expressed by the hydraulic properties of the medium. The region where saturation becomes viscously detained (temporarily entrapped) is determined by a critical water content θcrit that defines a viscous length LV behind the front tip. Theory developed to predict the critical water content θcrit and the characteristic secondary timescale τ was in good agreement with measured drainage characteristics using neutron radiography and direct imaging. The observed critical water content θcrit increased with higher drainage rates as predicted by theory with consideration of a percolation threshold. The observed slow drainage timescale τ as a function of mean drainage rate depended on the critical water content θcrit and the resulting counteracting effects of increased detained liquid volume and increased conductivity of the viscous limited region. The concept of drainage zonation illustrates how increasing flow rates enhances the extent of viscous limitations behind the main drainage front. The new insights could be useful for management of immiscible fluid displacement, quantification of averaging effects in experimental measurements (dynamic effects on pc‐S relationship), and explain some of the underpinnings of the field capacity phenomenon.
Adiponectin, hemoglobin, and cardiovascular risk in an indigenous siberian population
Authors: Streeter Elizabeth A. , Squires Erica C. , Leonard William R. , Tarskaia Larissa A. , Klimova Tatiana M. , Fedorova Valentina I. , Baltakhinova Marina E. , Krivoshapkin Vadim G. , Snodgrass J. Josh 
Published: November 2015

ObjectivesAdipose tissue hypoxia appears to play a role in promoting chronic inflammation and the development of obesity‐related cardiovascular and metabolic diseases, yet the underlying mechanisms are not well understood. The aim of the present research is to examine whether adiponectin levels (an adipocyte‐derived hormone with anti‐inflammatory properties) are inversely correlated with hemoglobin levels in an indigenous Siberian population.MethodsThe study was conducted among 252 Yakut adults (≥18 years; 135 females) from Berdygestiakh, Sakha Republic, Russia. Measurements included anthropometric dimensions (body mass index [BMI], waist circumference [WC], and percent body fat) and blood levels of hemoglobin and adiponectin.ResultsYakut females had higher adiponectin concentrations than males (15.1 ± 9.8 vs. 11.7 ± 10.6 µg/ml; P < 0.001), whereas males had higher hemoglobin levels (14.4 ± 1.4 vs. 12.6 ± 1.5 g/dL; P < 0.001). Body composition measures in both sexes were negatively associated with adiponectin and positively associated with hemoglobin. After adjusting for central adiposity and smoking, adiponectin levels were negatively correlated with hemoglobin levels in men (P < 0.05), but not in women (P = 0.511).ConclusionsThis investigation provides some support for the involvement of hypoxia‐related dysregulation of adiponectin associated with obesity and potentially cardiovascular disease. Am. J. Hum. Biol. 28:580–583, 2016. © 2015 Wiley Periodicals, Inc.
Cethrene: A Helically Chiral Biradicaloid Isomer of Heptazethrene
Authors: Ravat Prince , Šolomek Tomáš , Rickhaus Michel , Häussinger Daniel , Neuburger Markus , Baumgarten Martin , Juríček Michal 
Published: November 2015

AbstractWe report the synthesis and properties of “cethrene”, the only helically chiral isomer of heptazethrene with a biradicaloid singlet ground state. Cethrene gives a well‐resolved EPR spectrum at room temperature and its structure was confirmed by 2D NMR and absorption spectroscopies. Our experiments and calculations show that the helical twist affects its electronic properties and decreases the singlet–triplet energy gap when compared to that of planar heptazethrene. Cethrene undergoes an intramolecular cyclization within several hours at room temperature.
Visible‐Light‐Triggered Drug Release from TiO2 Nanotube Arrays: A Controllable Antibacterial Platform
Authors: Xu Jingwen , Zhou Xuemei , Gao Zhida , Song Yan‐Yan , Schmuki Patrik 
Published: November 2015

AbstractIn this work, we use a double‐layered stack of TiO2 nanotubes (TiNTs) to construct a visible‐light‐triggered drug delivery system. The key for visible light drug release is a hydrophobic cap on the nanotubes containing Au nanoparticles (AuNPs). The AuNPs allow for a photocatalytic scission of the hydrophobic chain under visible light. To demonstrate this principle, we loaded ampicillin (AMP) into the lower part of the TiO2 nanotube stack, triggered visible‐light‐induced release, and carried out antibacterial studies. The release from the platform becomes most controllable if the drug is silane‐grafted in the hydrophilic bottom layer for drug storage. Thus, visible light photocatalysis can also determine the release kinetics of the active drug from the nanotube wall.
Polarity‐reversal‐producing phase transfer of hydrophilic silver nanoclusters capped by a hyperbranched polymer from water to nonpolar organic solvents
Authors: Qu Fei , Niu Shuwen , You Jinmao 
Published: November 2015

ABSTRACTHyperbranched poly(ethylene imine) (PEI)‐capped Ag nanoclusters, synthesized starting from an aqueous environment, dispersed well in water and most polar organic solvents. However, with the addition of 1,4‐dioxane, the PEI‐capped Ag nanoclusters could be separated completely to obtain hydrophilic and hydrophobic Ag nanoclusters. Through this facile method, the successful phase transfer of PEI‐capped Ag nanoclusters from the aqueous phase to the nonpolar organic phase, such as from water to carbon tetrachloride, chloroform, and methylene bichloride, was easily realized. The polarity reversal of Ag nanoclusters were considered to be associated with the conformational change of PEI on the basis of the hydrophobic methylene groups of polymer backbone facing the external side or internal side, and this polarity reversal was irreversible. Moreover, PEIs with higher molecular weights showed a higher efficiency of phase transfer of the Ag nanoclusters. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43206.
Tunable luminescence properties and energy transfer in LaAl11O18:Eu,Tb phosphor
Authors: Mendhe M. S. , Puppalwar S. P. , Dhoble S. J. 
Published: November 2015

AbstractEu2+ and Tb3+ singly doped and co‐doped LaAl11O18 phosphors were prepared by a combustion method using urea as a fuel. The phase structure and photoluminescence (PL) properties of the prepared phosphors were characterized by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence excitation and emission spectra. When the content of Eu2+ was fixed at 0.01, the emission chromaticity coordinates could be adjusted from blue to green region by tuning the contents of Tb3+ ions from 0.01 to 0.03 through an energy transfer (ET) process. The fluorescence data collected from the samples with different contents of Tb3+ into LaAl11O18: Eu, show the enhanced green emission at 545 nm associated with 5D4 –7F5 transitions of Tb3+. The enhancement was attributed to ET from Eu2+ to Tb3+, and therefore Eu2+ ion acts as a sensitizer (an energy donor) while Tb3+ ion as an activator. The ET from Eu2+ to Tb3+ is performed through dipole–dipole interaction. The ET efficiency and critical distance were also calculated. The present Eu2+–Tb3+ co‐doped LaAl11O18 phosphor will have potential application for UV convertible white light‐emitting diodes. Copyright © 2015 John Wiley & Sons, Ltd.
Multiple Conformations of the Loop Region Confers Heat‐Resistance on SsArd1, a Thermophilic NatA
Authors: Chang Yu‐Yung , Hsu Chun‐Hua 
Published: November 2015

AbstractStructural comparison indicates that the loop region between β3 and β4 of SsArd1 is extended relative to the corresponding region in mesophilic Nats, and forms a plastic hydrogen‐bond network mainly at two serine residues. Strikingly, two single‐point mutants showed ∼3 °C decrease in melting temperature, and two other variants showed ∼7 °C decrease; this correlated with significantly reduced enzymatic activity. To our knowledge, this is the first discovery of a loop region capable of remarkably improving protein thermostability. This provides a novel route to engineer heat‐resistant proteins.
Ruthenium and Formic Acid Based Tandem Catalytic Transformation of Bioderived Furans to Levulinic Acid and Diketones in Water
Authors: Dwivedi Ambikesh D. , Gupta Kavita , Tyagi Deepika , Rai Rohit K. , Mobin Shaikh M. , Singh Sanjay K. 
Published: November 2015

AbstractEfficient tandem catalytic transformations of bioderived furans, such as furfural, 5‐hydroxymethylfurfural (5‐HMF), and 5‐methylfurfural (5‐MF), to levulinic acid (LA) and diketones, 1‐hydroxyhexane‐2,5‐dione (1‐HHD), 3‐hydroxyhexane‐2,5‐dione (3‐HHD), and hexane‐2,5‐dione (2,5‐HD), was achieved by using water‐soluble arene–RuII complexes, containing ethylenediamine‐based ligands, as catalysts in the presence of formic acid. The catalytic conversion of furans depends on the catalyst, ligand, formic acid concentration, reaction temperature, and time. Experimental evidence, including time‐resolved 1H NMR spectral studies, indicate that the catalytic reaction proceeds first with formyl hydrogenation followed by hydrolytic ring opening of furans. The ruthenium–formic acid tandem catalytic transformation of fructose to diketones and LA was also achieved. Finally, the molecular structures of the four representative arene–RuII catalysts were established by single‐crystal X‐ray diffraction studies.
Nanoscale Platelet Formation by Monounsaturated and Saturated Sophorolipids under Basic pH Conditions
Authors: Cuvier Anne‐Sophie , Babonneau Florence , Berton Jan , Stevens Christian V. , Fadda Giulia C. , Péhau‐Arnaudet Gérard , Le Griel Patrick , Prévost Sylvain , Perez Javier , Baccile Niki 
Published: November 2015

AbstractThe self‐assembly behavior of the yeast‐derived bolaamphiphile sophorolipid (SL) is generally studied under acidic/neutral pH conditions, at which micellar and fibrillar aggregates are commonly found, according to the (un)saturation of the aliphatic chain: the cis form, which corresponds to the oleic acid form of SL, spontaneously forms micelles, whereas the saturated form, which corresponds to the stearic acid form of SL, preferentially forms chiral fibers. By using small‐angle light and X‐ray scattering (SLS, SAXS) combined with high‐sensitivity transmission electron microscopy imaging under cryogenic conditions (cryo‐TEM), the nature of the self‐assembled structures formed by these two compounds above pH 10, which is the pH at which they are negatively charged due to the presence of a carboxylate group, has been explored. Under these conditions, these compounds self‐assemble into nanoscale platelets, despite the different molecular structures. This work shows that the electrostatic repulsion forces generated by COO− mainly drive the self‐assembly process at basic pH, in contrast with that found at pH below neutrality, at which self‐assembly is driven by van der Waals forces and hydrogen bonding, and thus, is in agreement with previous findings on carbohydrate‐based gemini surfactants.
Role of Magnetic Exchange Interactions in the Magnetization Relaxation of {3d–4f} Single‐Molecule Magnets: A Theoretical Perspective
Authors: Singh Saurabh Kumar , Beg Mohammad Faizan , Rajaraman Gopalan 
Published: November 2015

AbstractCombined density functional and ab initio calculations are performed on two isomorphous tetranuclear {Ni3IIILnIII} star‐type complexes [Ln=Gd (1), Dy (2)] to shed light on the mechanism of magnetic exchange in 1 and the origin of the slow magnetization relaxation in complex 2. DFT calculations correctly reproduce the sign and magnitude of the J values compared to the experiments for complex 1. Acute ∢NiOGd bond angles present in 1 instigate a significant interaction between the 4fxyz orbital of the GdIII ion and 3d orbital of the NiII ions, leading to rare and strong antiferromagnetic Ni⋅⋅⋅Gd interactions. Calculations reveal the presence of a strong next‐nearest‐neighbour Ni⋅⋅⋅Ni antiferromagnetic interaction in complex 1 leading to spin frustration behavior. CASSCF+RASSI‐SO calculations performed on complex 2 suggest that the octahedral environment around the DyIII ion is neither strong enough to stabilize the mJ |±15/2〉 as the ground state nor able to achieve a large ground‐state–first‐excited‐state gap. The ground‐state Kramers doublet for the DyIII ion is found to be the mJ |±13/2〉 state with a significant transverse anisotropy, leading to very strong quantum tunneling of magnetization (QTM). Using the POLY_ANISO program, we have extracted the JNiDy interaction as −1.45 cm−1. The strong Ni⋅⋅⋅Dy and next‐nearest‐neighbour Ni⋅⋅⋅Ni interactions are found to quench the QTM to a certain extent, resulting in zero‐field SMM behavior for complex 2. The absence of any ac signals at zero field for the structurally similar [Dy(AlMe4)3] highlights the importance of both the Ni⋅⋅⋅Dy and the Ni⋅⋅⋅Ni interactions in the magnetization relaxation of complex 2. To the best of our knowledge, this is the first time that the roles of both the Ni⋅⋅⋅Dy and Ni⋅⋅⋅Ni interactions in magnetization relaxation of a {3d–4f} molecular magnet have been established.
A novel analysis of color component for top dyed melange yarn with support vector machine
Authors: Shen Jiajia , Ma Hui , Chen Weiguo , Zhou Xiang 
Published: November 2015

AbstractIn view of the difficulty of distinguishing the color component in top dyed melange yarn due to the spectral overlap of the component colors, a novel color component analysis method based on support vector machine is presented. With this method, spectra data can be distinguished more accurately and effectively than with the traditional method—human‐eye detection—and therefore, the method will be very helpful for accurate color matching. In our work, the core idea was to convert the overlapped spectra data into linearly separable ones in a high dimension space, followed by recognition and determination of the composition of melange yarn by trained support vector machine classifier. The effects of four kernel functions, i.e., linear, radial basis kernel, sigmoid, and polynomial, as well as five spectral preprocessing methods, including amplification, first derivative, second derivative, principal components analysis, and L*a*b* values were studied. The results demonstrated that with the amplification factor of 100 of reflectance spectra coupled with L*a*b* as input data, and using radial basis kernel as kernel function, the highest recognition rate was achieved, with an average recognition rate of eight colors of 96.5%, indicating that it was a better color component analysis method for top dyed melange yarn. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 636–641, 2016
The Effect of Humidity upon the Crystallization Process of Two‐Step Spin‐Coated Organic–Inorganic Perovskites
Authors: Xu Yuzhuan , Zhu Lifeng , Shi Jiangjian , Xu Xin , Xiao Junyan , Dong Juan , Wu Huijue , Luo Yanhong , Li Dongmei , Meng Qingbo 
Published: November 2015

AbstractMoisture is shown to activate the reaction between PbI2 and methylammonium halides. In addition, two activating mechanisms are proposed for the formation of CH3NH3PbI3 and CH3NH3PbI3−xClx films from a series of carefully controlled experiments. When these rapidly formed perovskite films are directly fabricated into the devices, poor photovoltaic properties are found, due to heavy surface charge recombination. However, the cell performance can be significantly enhanced to 13.63 % and to over 12 % in the steady state for CH3NH3PbI3 and to 15.50 % and over 14 % in the steady state for CH3NH3PbI3−xClx, if the rapidly formed perovskite film is annealed. Thus, it is believed that moisture (below 60 % RH) is not a problem for the fabrication of highly efficient perovskite solar cells.
Assembling Supramolecular Dye‐Sensitized Photoelectrochemical Cells for Water Splitting
Authors: Ding Xin , Gao Yan , Ye Lu , Zhang Linlin , Sun Licheng 
Published: November 2015

AbstractThe method used to assemble dye‐sensitized photoelectrochemical (DS‐PEC) devices plays a vital role in determining its photoactivity and stability. We report a simple and effective method to assemble supramolecular DS‐PECs introducing PMMA as support material and a catalyst modified with long carbon chains as photoanodes. The long carbon chains in combination with PMMA allow to better immobilize the catalyst. DS‐PECs obtained by this simple method have display excellent photoactivities and stabilities. A photocurrent density of 1.1 mA cm−2 and a maximum IPCE of 9.5 % have been obtained with a 0.2 V vs NHE external bias.
Application of direct synthesis techniques to customize filters with complex frequency response
Authors: Xiao Fei 
Published: November 2015

SummaryRecently, direct synthesis techniques (DSTs) have been presented for filter synthesis. Unlike conventional synthesis techniques, DSTs derive the filtering polynomials of the filters to be synthesized directly in their own frequency domain. These filtering polynomials are real coefficient so that they might find applications in various fields. Furthermore, DSTs might be used to customize filters with a more complex frequency response, such as asymmetric frequency response or multi‐band frequency response. In this paper, DSTs are compared with some well‐known filter synthesis techniques. Then, the application of DSTs in the design of lumped‐element LC filters, distributed‐element filters, active RC filters, and infinite impulse response digital filters with complex frequency response is discussed. Some examples are presented for demonstration. Copyright © 2015 John Wiley & Sons, Ltd.
PCP Pincer Iridium Chemistry – Coordination of Pyridines to [(tBuPCP)IrH(Cl)]
Authors: Titova Ekaterina M. , Silantyev Gleb A. , Filippov Oleg A. , Gulyaeva Ekaterina S. , Gutsul Evgenii I. , Dolgushin Fedor M. , Belkova Natalia V. 
Published: November 2015

AbstractThe complexes of [(tBuPCP)IrH(Cl)] {1, tBuPCP = 1,3‐bis[(di‐tert‐butylphosphanyl)methyl]benzene} with pyridine (py, 2), 4‐aminopyridine (4apy, 3) and 2‐aminopyridine (2apy, 4) have been synthesized and fully characterized by variable‐temperature spectroscopy (NMR, IR, and UV/Vis). In each case, the reaction yields a mixture of cis‐ and trans‐hydrido–chlorido isomers. The stereochemistry of the latter was confirmed by single‐crystal X‐ray analysis of 2a and 3a, which showed that the pyridine ligands coordinated opposite the aryl ring do not produce an additional twist of the pincer ligand but lead to the elongation of all bonds involving the iridium atom. The chlorido ligand becomes substantially labilized owing to the strong trans effect of the hydrido ligand, and that in 3a it is prone to intermolecular N–H···Cl hydrogen bonding in the solid state. In the 2‐aminopyridine complex 4, the intramolecular hydrogen bond to the chlorido ligand (isomer 4a′) is slightly more preferred over the N–H···H bond (isomer 4a). The structures of the cis‐hydrido–chlorido isomers 2b–4b were established with the help of 15N‐labeled pyridine. These isomers undergo fast ligand exchange on the NMR timescale that slows as the temperature decreases. The decoalescence temperature is the lowest for the 2‐aminopyridine derivative 4b; therefore, it is the least stable. The repulsion between the tert‐butyl groups of the pincer ligand and the o‐NH2 group is the main reason for the lower stability of 4b.
Stereoselective Synthesis of P‐Stereogenic N‐Phosphinyl Compounds
Authors: Chelouan Ahmed , Recio Rocío , Álvarez Eleuterio , Khiar Noureddine , Fernández Inmaculada 
Published: November 2015

AbstractA number of P‐stereogenic N‐phosphinyl compounds were stereoselectively prepared in good yields by a straightforward approach, thanks to the diversified and, up until now, unexplored reactivity of (R)‐ and (S)‐dicyclohexylidene‐D‐glucose methyl phenyl phosphinates toward metal amides. Under adequate conditions, structurally different phosphinamides with one or two P‐chiral centers were obtained.