bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantifying atmospheric methane emissions from the Haynesville, Fayetteville, and northeastern Marcellus shale gas production regions
Authors: Peischl J. , Ryerson T. B. , Aikin K. C. , de Gouw J. A. , Gilman J. B. , Holloway J. S. , Lerner B. M. , Nadkarni R. , Neuman J. A. , Nowak J. B. , Trainer M. , Warneke C. , Parrish D. D. 
Published: February 2015

AbstractWe present measurements of methane (CH4) taken aboard a NOAA WP‐3D research aircraft in 2013 over the Haynesville shale region in eastern Texas/northwestern Louisiana, the Fayetteville shale region in Arkansas, and the northeastern Pennsylvania portion of the Marcellus shale region, which accounted for the majority of Marcellus shale gas production that year. We calculate emission rates from the horizontal CH4 flux in the planetary boundary layer downwind of each region after subtracting the CH4 flux entering the region upwind. We find 1 day CH4 emissions of (8.0 ± 2.7) × 107 g/h from the Haynesville region, (3.9 ± 1.8) × 107 g/h from the Fayetteville region, and (1.5 ± 0.6) × 107 g/h from the Marcellus region in northeastern Pennsylvania. Finally, we compare the CH4 emissions to the total volume of natural gas extracted from each region to derive a loss rate from production operations of 1.0–2.1% from the Haynesville region, 1.0–2.8% from the Fayetteville region, and 0.18–0.41% from the Marcellus region in northeastern Pennsylvania. The climate impact of CH4 loss from shale gas production depends upon the total leakage from all production regions. The regions investigated in this work represented over half of the U.S. shale gas production in 2013, and we find generally lower loss rates than those reported in earlier studies of regions that made smaller contributions to total production. Hence, the national average CH4 loss rate from shale gas production may be lower than values extrapolated from the earlier studies.
Impact of equatorial ionospheric irregularities on GNSS receivers using real and synthetic scintillation signals
Authors: Ghafoori F. , Skone S. 
Published: February 2015

AbstractThe impact of L‐band equatorial ionospheric scintillation on Global Navigation Satellite Systems (GNSS) receivers is investigated in this paper using both real and synthetic scintillation data. To this end, various low‐latitude data sets, recorded during the most recent solar maximum, are exploited in post‐processing to develop and verify realistic simulation tools and evaluate GNSS receiver performance. A scintillation simulation model is implemented based on the phase screen formulation of Dr. Charles Rino (1979, 1982, and 2011) which allows oblique signal propagation in an anisotropic propagation medium with multiple irregularity layers (or phase screens) for multiple GNSS frequencies. The observed real scintillation parameters are used to drive GNSS signal simulations. The subsequent simulated GNSS signal time series are verified through comparison with real data for different signal tracking states including the most severe and challenging tracking scenarios. Using both real and synthetic data sets, the impact of scintillation on observation quality and receiver performance is evaluated in terms of probability of loss of phase and frequency lock, as well as the correlation of disturbed L‐band signals transmitted by GNSS satellites on the same transionsopheric path.
Detection of traveling ionospheric disturbances by medium‐frequency Doppler sounding using AM radio transmissions
Authors: Chilcote M. , LaBelle J. , Lind F. D. , Coster A. J. , Miller E. S. , Galkin I. A. , Weatherwax A. T. 
Published: February 2015

AbstractNighttime traveling ionosphere disturbances (TIDs) propagating in the lower F region of the ionosphere have been detected by measuring time variations in the Doppler shifts of commercial AM radio broadcast signals. Three receivers, components of the Intercepted Signals for Ionospheric Science (ISIS) Array software radio instrumentation network in the northeastern United States, recorded signals from two radio stations during 11 nights in March–April, 2012. By combining these measurements, TIDs were detected as approximately 40min periodic variations in the frequencies of the received signals resulting from Doppler shifts produced by the ionosphere. The variations had amplitudes of up to a few tenths of a hertz and were correlated across the array. For one study interval, 0000–0400 UT on 13 April 2012, simultaneous GPS total electron content, Digisonde®, and Super Dual‐Auroral Radar Network coherent backscatter radar measurements confirmed the detection of TIDs with the same characteristics. Besides TIDs, the receiver network often detected large (nearly 1 Hz) upward (downward) Doppler shifts of the AM broadcast signals at the dawn (dusk) terminator. These results demonstrate that AM radio signals can be used for detection and monitoring of nighttime TIDs and related effects.
Can an Intensive Diet and Exercise Program Prevent Knee Pain Among Overweight Adults at High Risk?
Authors: White Daniel K. , Neogi Tuhina , Rejeski W. Jack , Walkup Michael P. , Lewis Cora E. , Nevitt Michael C. , Foy Capri G. , Felson David T. ,   for the Look AHEAD Research Group
Published: February 2015

ObjectiveIt is unclear whether an intensive program of weight loss combined with exercise prevents the onset of knee pain among those at high risk. We examined whether an intensive lifestyle intervention (ILI) prevents incident knee pain compared with a diabetes mellitus support and education (DSE) comparison group among overweight adults with diabetes mellitus.MethodsWe conducted a secondary analysis of the Action for Health in Diabetes (Look AHEAD) study, which is a randomized intervention trial of adults who were obese and had type 2 diabetes mellitus starting in 2001. We studied a subcohort of 2,889 subjects who reported no knee pain at baseline but were at high risk due to obesity. Risk ratios (RRs) were calculated to examine the association of ILI versus DSE with incident knee pain at year 1 and year 4. All analyses were adjusted for potential confounders.ResultsAge, sex, and body mass index were similar among ILI and DSE participants with no knee pain at baseline. At year 1, ILI participants were 15% less likely to develop knee pain compared with DSE participants (RR 0.85, 95% confidence interval 0.74–0.98). At year 4, this difference decreased to 5% and was no longer statistically significant.ConclusionAn ILI of diet and exercise may prevent the development of knee pain among those at high risk in the short term. Health care providers may consider recommending diet and exercise as a means to prevent the development of knee pain among those at high risk.
Solid‐State 17O NMR Spectroscopy of Paramagnetic Coordination Compounds
Authors: Kong Xianqi , Terskikh Victor V. , Khade Rahul L. , Yang Liu , Rorick Amber , Zhang Yong , He Peng , Huang Yining , Wu Gang 
Published: February 2015

AbstractHigh‐quality solid‐state 17O (I=5/2) NMR spectra can be successfully obtained for paramagnetic coordination compounds in which oxygen atoms are directly bonded to the paramagnetic metal centers. For complexes containing VIII (S=1), CuII (S=1/2), and MnIII (S=2) metal centers, the 17O isotropic paramagnetic shifts were found to span a range of more than 10 000 ppm. In several cases, high‐resolution 17O NMR spectra were recorded under very fast magic‐angle spinning (MAS) conditions at 21.1 T. Quantum‐chemical computations using density functional theory (DFT) qualitatively reproduced the experimental 17O hyperfine shift tensors.
Target‐Based Whole‐Cell Screening by 1H NMR Spectroscopy
Authors: Ma Junhe , Cao Qing , McLeod Sarah M. , Ferguson Keith , Gao Ning , Breeze Alexander L. , Hu Jun 
Published: February 2015

AbstractAn NMR‐based approach marries the two traditional screening technologies (phenotypic and target‐based screening) to find compounds inhibiting a specific enzymatic reaction in bacterial cells. Building on a previous study in which it was demonstrated that hydrolytic decomposition of meropenem in living Escherichia coli cells carrying New Delhi metallo‐β‐lactamase subclass 1 (NDM‐1) can be monitored in real time by NMR spectroscopy, we designed a cell‐based NMR screening platform. A strong NDM‐1 inhibitor was identified with cellular IC50 of 0.51 μM, which is over 300‐fold more potent than captopril, a known NDM‐1 inhibitor. This new screening approach has great potential to be applied to targets in other cell types, such as mammalian cells, and to targets that are only stable or functionally competent in the cellular environment.
Regioselektive Pd‐katalysierte Methoxycarbonylierung von Alkenen unter Verwendung von Paraformaldehyd/Methanol als CO‐Surrogat
Authors: Liu Qiang , Yuan Kedong , Arockiam Percia‐Beatrice , Franke Robert , Doucet Henri , Jackstell Ralf , Beller Matthias 
Published: February 2015

AbstractIn den letzten Jahren wurde intensiv an der Entwicklung neuartiger carbonylierender Transformationen mit CO‐Alternativen geforscht, die es ermöglichen, das toxische CO‐Gas durch besser handhabbare anorganische oder organische Carbonylverbindungen zu ersetzen. Hier wird über die erste regioselektive Methoxycarbonylierung von Alkenen mit Paraformaldehyd und Methanol als CO‐Ersatz berichtet. Dieses neue Verfahren ist für eine Reihe von Alkenen in Gegenwart von Palladium‐Katalysatoren unter relativ milden Bedingungen anwendbar und wesentlich atomeffizienter als früher beschriebene CO‐Alternativen.
A Superamphiphobic Coating with an Ammonia‐Triggered Transition to Superhydrophilic and Superoleophobic for Oil–Water Separation
Authors: Xu Zhiguang , Zhao Yan , Wang Hongxia , Wang Xungai , Lin Tong 
Published: February 2015

AbstractSuperhydrophilic and superoleophobic materials are very attractive for efficient and cost‐effective oil–water separation, but also very challenging to prepare. Reported herein is a new superamphiphobic coating that turns superhydrophilic and superoleophobic upon ammonia exposure. The coating is prepared from a mixture of silica nanoparticles and heptadecafluorononanoic acid‐modified TiO2 sol by a facile dip‐coating method. Commonly used materials, including polyester fabric and polyurethane sponge, modified with this coating show unusual capabilities for controllable filtration of an oil–water mixture and selective removal of water from bulk oil. We anticipate that this novel coating may lead to the development of advanced oil–water separation techniques.
Exploring Diradical Chemistry: A Carbon‐Centered Radical May Act as either an Anion or Electrophile through an Orbital Isomer
Authors: Gonçalves Théo P. , Mohamed Mubina , Whitby Richard J. , Sneddon Helen F. , Harrowven David C. 
Published: February 2015

AbstractDiradical intermediates, formed by thermolysis of alkynylcyclobutenones, can display radical, anion, or electrophilic character because of the existence of an orbital isomer with zwitterionic and cyclohexatrienone character. Our realization that water, alcohols, and certain substituents can induce the switch provides new opportunities in synthesis. For example, it can be used to shut down radical pathways and to give access to aryl carbonates and tetrasubstituted quinones.
Hybrid Fibers Made of Molybdenum Disulfide, Reduced Graphene Oxide, and Multi‐Walled Carbon Nanotubes for Solid‐State, Flexible, Asymmetric Supercapacitors
Authors: Sun Gengzhi , Zhang Xiao , Lin Rongzhou , Yang Jian , Zhang Hua , Chen Peng 
Published: February 2015

AbstractOne of challenges existing in fiber‐based supercapacitors is how to achieve high energy density without compromising their rate stability. Owing to their unique physical, electronic, and electrochemical properties, two‐dimensional (2D) nanomaterials, e.g., molybdenum disulfide (MoS2) and graphene, have attracted increasing research interest and been utilized as electrode materials in energy‐related applications. Herein, by incorporating MoS2 and reduced graphene oxide (rGO) nanosheets into a well‐aligned multi‐walled carbon nanotube (MWCNT) sheet followed by twisting, MoS2‐rGO/MWCNT and rGO/MWCNT fibers are fabricated, which can be used as the anode and cathode, respectively, for solid‐state, flexible, asymmetric supercapacitors. This fiber‐based asymmetric supercapacitor can operate in a wide potential window of 1.4 V with high Coulombic efficiency, good rate and cycling stability, and improved energy density.
Unexpected Self‐Sorting Self‐Assembly Formation of a [4:4] Sulfate:Ligand Cage from a Preorganized Tripodal Urea Ligand
Authors: Pandurangan Komala , Kitchen Jonathan A. , Blasco Salvador , Boyle Elaine M. , Fitzpatrick Bella , Feeney Martin , Kruger Paul E. , Gunnlaugsson Thorfinnur 
Published: February 2015

AbstractThe design and synthesis of tripodal ligands 1–3 based upon the N‐methyl‐1,3,5‐benzenetricarboxamide platform appended with three aryl urea arms is reported. This ligand platform gives rise to highly preorganized structures and is ideally suited for binding SO42− and H2PO4− ions through multiple hydrogen‐bonding interactions. The solid‐state crystal structures of 1–3 with SO42− show the encapsulation of a single anion within a cage structure, whereas the crystal structure of 1 with H2PO4− showed that two anions are encapsulated. We further demonstrate that ligand 4, based on the same platform but consisting of two bis‐urea moieties and a single ammonium moiety, also recognizes SO42− to form a self‐assembled capsule with [4:4] SO42−:4 stoichiometry in which the anions are clustered within a cavity formed by the four ligands. This is the first example of a self‐sorting self‐assembled capsule where four tetrahedrally arranged SO42− ions are embedded within a hydrophobic cavity.
Cobalt‐Catalyzed Negishi Cross‐Coupling Reactions of (Hetero)Arylzinc Reagents with Primary and Secondary Alkyl Bromides and Iodides
Authors: Hammann Jeffrey M. , Haas Diana , Knochel Paul 
Published: February 2015

AbstractWe report a cobalt‐catalyzed cross‐coupling of di(hetero)arylzinc reagents with primary and secondary alkyl iodides or bromides using THF‐soluble CoCl2⋅2 LiCl and TMEDA as a ligand, which leads to the corresponding alkylated products in up to 88 % yield. A range of functional groups (e.g. COOR, CN, CF3, F) are tolerated in these substitution reactions. Remarkably, we do not observe rearrangement of secondary alkyl iodides to unbranched products. Additionally, the use of cyclic TBS‐protected iodohydrins leads to trans‐2‐arylcyclohexanol derivatives in excellent diastereoselectivities (up to d.r.=99:1).
Efficient Cu‐catalyzed Atom Transfer Radical Addition Reactions of Fluoroalkylsulfonyl Chlorides with Electron‐deficient Alkenes Induced by Visible Light
Authors: Tang Xiao‐Jun , Dolbier William R. 
Published: February 2015

AbstractFluoroalkylsulfonyl chlorides, RfSO2Cl, in which Rf=CF3, C4F9, CF2H, CH2F, and CH2CF3, are used as a source of fluorinated radicals to add fluoroalkyl groups to electron‐deficient, unsaturated carbonyl compounds. Photochemical conditions, using Cu mediation, are used to produce the respective α‐chloro‐β‐fluoroalkylcarbonyl products in excellent yields through an atom transfer radical addition (ATRA) process. Facile nucleophilic replacement of the α‐chloro substituent is shown to lead to further diverse functionalization of the products.
Fabrication of Condensate Microdrop Self‐Propelling Porous Films of Cerium Oxide Nanoparticles on Copper Surfaces
Authors: Luo Yuting , Li Juan , Zhu Jie , Zhao Ye , Gao Xuefeng 
Published: February 2015

AbstractCondensate microdrop self‐propelling (CMDSP) surfaces have attracted intensive interest. However, it is still challenging to form metal‐based CMDSP surfaces. We design and fabricate a type of copper‐based CMDSP porous nanoparticle film. An electrodeposition method based on control over the preferential crystal growth of isotropic nanoparticles and synergistic utilization of tiny hydrogen bubbles as pore‐making templates is adopted for the in situ growth of cerium oxide porous nanoparticle films on copper surfaces. After characterizing their microscopic morphology, crystal structure and surface chemistry, we explore their CMDSP properties. The nanostructure can realize the efficient ejection of condensate microdrops with sizes below 50 μm.
Enhanced thermal stability of biomedical thermoplastic polyurethane with the addition of cellulose nanocrystals
Authors: Liu Jen‐Chieh , Martin Darren J. , Moon Robert J. , Youngblood Jeffrey P. 
Published: February 2015

ABSTRACTFreeze‐dried cellulose nanocrystals (CNCs) were dispersed in the thermoplastic polyurethane [Pellethane 2363‐55D (P55D)] by a solvent casting method to fabricate CNC‐reinforced nanocomposites. This study demonstrated that the addition of small amounts (1–5 wt %) of CNCs to P55D increased the thermal degradation temperature while maintaining a similar stiffness, strength, and elongation of the neat P55D. CNC additions to P55D did not alter the glass‐transition temperature, but the onset decomposition temperature was shifted from 286 to 327°C when 1 wt % CNCs was dispersed in the matrix. The higher onset decomposition temperature was attributed to the formation of hydrogen bonds between the hydroxyl groups on the CNC surface and urethane groups in the hard block of P55D. The ultimate tensile strength and strain to failure (εf) of the nanocomposites were minimally affected by additions up to 5 wt % CNCs, whereas the elastic modulus was increased by about 70%. The observation that εf was unchanged with the addition of up to 5 wt % CNCs suggested that the flow/sliding of the hard blocks and chains were not hindered by the presence of the CNCs during plastic deformation. The ramifications of this study was that CNC additions resulted in wider processing temperatures of P55D for various biomedical devices while maintaining a similar stiffness, strength, and elongation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41970.
Preparation and characterization of Rana chensinensis skin extract/poly(ε‐caprolactone) electrospun membranes as antibacterial fibrous mats
Authors: Zhang Mei , Xu Wen‐Yu , Wang Jia‐Mian , Luan Jia‐Shuang , Dong He‐Nan , Zhang Yu‐Jing , Li Xue‐Qi , Sun Da‐Hui 
Published: February 2015

ABSTRACTIn this study, membranes composed of Rana chensinensis skin extracts (RCSEs) and poly(ε‐caprolactone) (PCL) were fabricated by an electrospinning technique. The RCSEs were prepared by the extraction of R. chensinensis skin with acetic acid solution, and the electrospun membranes were prepared by the mixture of RCSEs and PCL in 1,1,1,3,3,3‐hexafluoro‐2‐propanol before electrospinning. The membranes were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and were subjected to mechanical tests (tensile and nanoindentation) and antibacterial evaluation. The results indicate that the surface roughness of the fibers clearly decreased with the increase in the amount of PCL in the membranes. The mechanical test indicated that PCL played a dominant role in the mechanical strength of the RCSE/PCL electrospun membranes. As a potential bactericidal packaging material for practical applications, the antibacterial activity results indicate that the membranes had antibacterial effects against Staphylococcus aureus and Escherichia coli. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42030.
The effects of pH and surfactants on the absorption and fluorescence properties of ochratoxin A and zearalenone
Authors: Li Taihua , Kim Bo Bae , Ha Tae Hwan , Shin Yong‐Beom , Kim Min‐Gon 
Published: February 2015

AbstractThe pH and surfactant dependencies of the absorption and fluorescence properties of ochratoxin A (OTA) and zearalenone (ZEN), the main mycotoxins found as contaminants in foods and feeds, were evaluated. Three surfactants with different ionic properties were investigated, namely sodium dodecyl sulfate (SDS, anionic), Tween 20 (nonionic) and hexadecyltrimethylammonium bromide (CTAB, cationic). The results show that the effects of pH on the absorption wavelength maxima and fluorescence efficiencies of the mycotoxins, which are a consequence of the presence of acidic phenol and/or carboxyl containing fluorophores, are dependent on the ionic nature of the added surfactants. Specifically, the fluorescence responses to pH changes of OTA and ZEN are similar in the presence or absence of Tween 20 and SDS. By contrast, the pH‐dependent fluorescence properties of these mycotoxins are altered when CTAB is present in the solutions. Moreover, unlike OTA, ZEN in aqueous solution displays almost no fluorescence. However, fluorescence enhancement takes place when surfactants are present in aqueous solutions of this mycotoxin. The results of this study demonstrate that the different microenvironments, present in the organized micellar systems created by the individual surfactants, can be potentially employed to modulate the sensitivities and selectivities of the fluorescence detection of OTA or ZEN. Copyright © 2015 John Wiley & Sons, Ltd.
Identification of a New Diterpene Biosynthetic Gene Cluster that Produces O‐Methylkolavelool in Herpetosiphon aurantiacus
Authors: Nakano Chiaki , Oshima Misaki , Kurashima Nodoka , Hoshino Tsutomu 
Published: February 2015

AbstractDiterpenoids are usually found in plants and fungi, but are rare in bacteria. We have previously reported new diterpenes, named tuberculosinol and isotuberculosinol, which are generated from the Mycobacterium tuberculosis gene products Rv3377c and Rv3378c. No homologous gene was found at that time, but we recently found highly homologous proteins in the Herpetosiphon aurantiacus ATCC 23779 genome. Haur_2145 was a class II diterpene cyclase responsible for the conversion of geranylgeranyl diphosphate into kolavenyl diphosphate. Haur_2146, homologous to Rv3378c, synthesized (+)‐kolavelool through the nucleophilic addition of a water molecule to the incipient cation formed after the diphosphate moiety was released. Haur_2147 afforded (+)‐O‐methylkolavelool from (+)‐kolavelool, so this enzyme was an O‐methyltransferase. This new diterpene was indeed detected in H. aurantiacus cells. This is the first report of the identification of a (+)‐O‐methylkolavelool biosynthetic gene cluster.
Selective Oxidation of Salicylic Alcohol to Aldehyde with O2/H2 using Au‐Pd on Titanate Nanotubes Catalysts
Authors: Torrente‐Murciano Laura , Villager Thomas , Chadwick David 
Published: February 2015

AbstractAlcohol oxidation with 100 % selectivity to the aldehyde product (versus acid formation) is achieved at mild conditions by a tandem‐type system where the intermediate species of hydrogen peroxide formation from an O2/H2 mixture are formed and utilised directly over Au‐Pd/Ti‐NT catalysts. In situ reaction of the intermediate species minimises the parallel decomposition of hydrogen peroxide into water, overcoming one of the limitations on the use of hydrogen peroxide as a green oxidant.