bluuebunny/crossref_metadata_2025_split huggingface dataset:
The atmospheric HCHO budget at Dumont d'Urville (East Antarctica): Contribution of photochemical gas‐phase production versus snow emissions
Authors: Preunkert Susanne , Legrand Michel , Pépy Guillaume , Gallée Hubert , Jones Anna , Jourdain Bruno 
Published: November 2013

AbstractHCHO was monitored throughout the year 2009 at the coastal East Antarctic site of Dumont d'Urville (DDU) using Aerolaser AL‐4021 analyzers. The accurate determination of less than 100 pptv required optimization of the analyzers, in particular, to minimize effects of changing ambient temperatures. The impact of station activities and of the presence of large penguin colonies at the site in summer was scrutinized. The obtained contamination‐free record indicates monthly means close to 50 pptv from May to September and a maximum of 200 pptv in January. Zero‐dimensional and 2‐D calculations suggest that in summer, the largest HCHO source is the gas‐phase photochemistry (80%) mainly driven by methane oxidation, which is considerably greater than from snow emissions (20%). The influence of light alkenes, dimethyl sulfide, and halogens remains weak. In winter, snow emissions represent the main HCHO source (70%). These findings are compared to previous studies conducted at the West Antarctic coast. It is shown that in summer the HCHO production from methane chemistry is 3 times more efficient at DDU than at the west coast due to more frequent arrival of oxidant‐rich air masses from inland Antarctica. Halogen chemistry is found to represent a weak HCHO sink at both West and East Antarctica. Compared to DDU, the shallower atmospheric boundary layer and the less efficient gas‐phase production at the west coast make the snow pack the dominant HCHO source (85%) compared to gas‐phase photochemistry (15%) there in summer.
Analysis of ATMS striping noise from its Earth scene observations
Authors: Qin Zhengkun , Zou Xiaolei , Weng Fuzhong 
Published: November 2013

AbstractThe differences between brightness temperature observations and simulated observations based on numerical weather predictions, i.e., O‐B, for Advanced Technology Microwave Sounder (ATMS) temperature sounding channels exhibit a clear striping pattern [Bormann et al., 2013]. We propose to first use the principal component analysis to isolate scan‐dependent features such as the cross‐track striping from the atmospheric signal and then to use an Ensemble Empirical Mode Decomposition (EEMD) to extract the striping noise in ATMS Earth scene brightness temperature observations for both temperature and water vapor sounding channels. It is shown that the Principal Component (PC) coefficient of the first PC mode, which mainly describes a scan‐dependent feature of cross‐track radiometer measurements, captures the striping noise. The EEMD is then applied to the PC coefficient to extract the first three high‐frequency intrinsic mode functions (IMFs), which are denoted as the PC1/IMF3 noise. When the PC1/IMF3 noise is removed from the data, the striping noise is imperceptible in the global distribution of O‐B for ATMS temperature sounding channels 1–16. Using the same method, it is demonstrated that the striping noise is also present in ATMS water vapor sounding channels 17–22. The magnitude of the ATMS striping noise is about ±0.3 K for the temperature sounding channels and ±1.0 K for the moisture sounding channels. The same technique is also applied to Advanced Microwave Sounding Unit‐A (AMSU‐A), AMSU‐B, and Microwave Humidity Sounder (MHS). The striping noise is undetectable for AMSU‐A but present in AMSU‐B and MHS data.
Noise performance of the CrIS instrument
Authors: Zavyalov Vladimir , Esplin Mark , Scott Deron , Esplin Benjamin , Bingham Gail , Hoffman Erik , Lietzke Christopher , Predina Joseph , Frain Rebecca , Suwinski Lawrence , Han Yong , Major Charles , Graham Brandon , Phillips Lee 
Published: November 2013

AbstractThe Cross‐track Infrared Sounder (CrIS) is a spaceborne Fourier transform spectrometer (FTS) that was launched into orbit on 28 October 2011 onboard the Suomi National Polar‐orbiting Partnership satellite. CrIS is a sophisticated sounding sensor that accurately measures upwelling infrared radiance at high spectral resolution. Data obtained from this sensor are used for atmospheric profiles retrieval and assimilation by numerical weather prediction models. Optimum vertical sounding resolution is achieved with high spectral resolution and multiple spectral channels; however, this can lead to increased noise. The CrIS instrument is designed to overcome this problem. Noise Equivalent Differential Radiance (NEdN) is one of the key parameters of the Sensor Data Record product. The CrIS on‐orbit NEdN surpasses mission requirements with margin and has comparable or better performance when compared to heritage hyperspectral sensors currently on orbit. This paper describes CrIS noise performance through the characterization of the sensor's NEdN and compares it to calibration data obtained during ground test. In addition, since FTS sensors can be affected by vibration that leads to spectrally correlated noise on top of the random noise inherent to infrared detectors, this paper also characterizes the CrIS NEdN with respect to the correlated noise contribution to the total NEdN. Lastly, the noise estimated from the imaginary part of the complex FTS spectra is extremely useful to assess and monitor in‐flight FTS sensor health. Preliminary results on the imaginary spectra noise analysis are also presented.
Control of Rabinovich chaotic system using sliding mode control
Authors: Kocamaz Uğur Erkin , Uyaroğlu Yılmaz , Kizmaz Hakan 
Published: November 2013

SUMMARYThis paper investigates the control of the continuous time Rabinovich chaotic system with the sliding mode control method. Based on the properties of the sliding mode theory, the controllers are designed and added to the nonlinear Rabinovich system. Numerical simulations show that the Rabinovich chaotic system can be regulated to its equilibrium points in the state space by using the sliding mode controllers, which verifies all the theoretical analyses. Simulation results of the proposed sliding mode control strategy have been also compared with the passive control method, and their performances are discussed. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis of 3,5‐Disubstituted Cyclohex‐2‐en‐1‐one via a Five‐Step Domino Reaction Catalyzed by Secondary Amines: Formation of (E)‐α,β‐Unsaturated Methyl Ketones
Authors: Ghorai Manas K. , Samanta Sauvik , Das Subhomoy 
Published: November 2013

AbstractA simple strategy for the synthesis of 5‐substituted‐3‐methylcyclohex‐2‐en‐1‐ones by proline‐catalyzed five‐step domino reactions of acetone and aromatic aldehydes is reported. The starting materials are stirred in the presence of L‐proline for 24 h then heated to 45 °C for a further 4‐6 h. The method can also be changed to exclusively form α,β‐unsaturated methyl ketones with >99 % E‐selectivity by heating the mixture to 80 °C in the second stage.
Organocatalytic Enantioselective Friedel–Crafts Reaction of 1‐Naphthols with Isatins and an Unexpected Spontaneous Dehydration Process
Authors: Wu Deyan , Zhang Xuwen , Xu Yong , Xue Yingfei , Li Jian , Wang Wei , Zhu Jin 
Published: November 2013

AbstractAn organocatalytic enantioselective Friedel–Crafts alkylation of 1‐naphthols with isatins has been developed. The process is catalyzed by a simple cinchona alkaloid derived thiourea and gives biologically interesting, enantioenriched 3‐(naphthalen‐2‐yl)‐3‐hydroxy‐2‐oxindoles in moderate to good yields of 42–83 % and with good to high enantioselectivity of up to 94 % ee. Furthermore, an unexpected intramolecular dehydration reaction proceeds spontaneously with 4‐substituted 1‐naphthols to offer structurally different ketone oxindoles.
Nutzung natürlicher Proteinsymmetrie zum Design lichtschaltbarer Enzyminhibitoren
Authors: Reisinger Bernd , Kuzmanovic Natascha , Löffler Patrick , Merkl Rainer , König Burkhard , Sterner Reinhard 
Published: November 2013

AbstractDie Aktivität des metabolischen Schlüsselenzyms PriA aus Mycobacterium tuberculosis (mtPriA) kann reversibel durch Licht kontrolliert werden. Auf der Grundlage des Dithienylethen‐Gerüsts wurden entsprechend der zweifachen Rotationssymmetrie des Proteins symmetrische Inhibitoren mit terminalen Ankern entworfen. Durch Schalten vom flexiblen, offenen Isomer zur starren, geschlossenen Form wurde die Inhibitionsaktivität um eine Größenordnung reduziert.
Simple and Compelling Biomimetic Metal–Organic Framework Catalyst for the Degradation of Nerve Agent Simulants
Authors: Katz Michael J. , Mondloch Joseph E. , Totten Ryan K. , Park Jin K. , Nguyen SonBinh T. , Farha Omar K. , Hupp Joseph T. 
Published: November 2013

AbstractInspired by biology, in which a bimetallic hydroxide‐bridged zinc(II)‐containing enzyme is utilized to catalytically hydrolyze phosphate ester bonds, the utility of a zirconium(IV)‐cluster‐containing metal–organic framework as a catalyst for the methanolysis and hydrolysis of phosphate‐based nerve agent simulants was examined. The combination of the strong Lewis‐acidic ZrIV and bridging hydroxide anions led to ultrafast half‐lives for these solvolysis reactions. This is especially remarkable considering that the actual catalyst loading was a mere 0.045 % as a result of the surface‐only catalysis observed.
Umkodierung des genetischen Codes mit Selenocystein
Authors: Bröcker Markus J. , Ho Joanne M. L. , Church George M. , Söll Dieter , O'Donoghue Patrick 
Published: November 2013

AbstractDer Selenocystein(Sec)‐Einbau in Proteine erfolgt in der Natur durch die kotranslationale Umkodierung eines UGA‐Stopp‐Codons. Diese Studie zeigt nun, dass Sec nicht ausschließlich durch UGA, sondern vielmehr durch 58 aller 64 möglichen Codons kodiert werden kann. Hierbei erlauben 15 Codons nicht nur die vollständige Umkodierung von ihrer ursprünglichen Bedeutung als kanonische Aminosäure zu Selenocystein, sondern sie führen zu Proteinausbeuten, die um mehr als das Zehnfache gesteigert sind. Der hoch effiziente Mechanismus zur Selenocystein‐Rekodierung wird anhand zweier Reporterenzyme, der Escherichia‐coli‐Formiatdehydrogenase und der humanen Thioredoxinreduktase, beschrieben. Da der Selenocysteineinbau an der Position eines UGA‐Stopp‐Codons zwangsläufig mit translationaler Termination konkurriert, war es umso erstaunlicher, dass die Selenocystein‐Einbaumaschinerie während der Umkodierung von Sense‐Codons erfolgreich mit den im Überfluss vorhandenen regulären Aminoacyl‐tRNAs konkurriert.
Furan/imide Diels–Alder polymers as dielectric materials
Authors: Lorenzini Robert G. , Sotzing Gregory A. 
Published: November 2013

ABSTRACTHerein, the synthesis and characterization of a series of Diels–Alder (DA) polymers made with various bis‐furans and 1,3‐bis(maleimide)propane are described. Due to the fact that these syntheses produce no byproducts inherent to their mechanism, as well as the relative ease at which highly functionalized monomers can be made, these polymers are identified as candidates for dielectric materials with high dielectric constants. The dielectric spectra of these polymers are reported, with an emphasis placed on describing observed structure–property trends. Dielectric constants for these materials range from 4.31 to 6.75 at room temperature, with dielectric losses in the 1–2% regime. These polymers are thermally stable to ∼130°C, where the retro DA reaction was confirmed with multiple analytical methods, including thermogravimetric analysis, differential scanning calorimetry, and gas chromatography/mass spectrometry thermal desorption spectroscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40179.
Microtextured polystyrene surfaces for three‐dimensional cell culture made by a simple solvent treatment method
Authors: DeRosa Michael E. , Hong Yulong , Faris Ronald A. , Rao Hongwei 
Published: November 2013

ABSTRACTThis article describes a solvent treatment process for transforming standard flat polystyrene surfaces into textured microenvironments for three‐dimensional (3D) cell culture. The process can be used with off‐the‐shelf microplates having 6, 12, 96, or even 384‐well formats and completed in a few steps. The surface microtexture resembles tightly packed, non‐interconnected micropores having a median pore size of either 115 or 19 μm depending on the strength of the solvent mixture. Hansen solubility parameter analysis was used to map out the polymer–solvent interaction conditions necessary for creating the surface texture. Primary human hepatocytes cultured on two‐dimensional control surfaces attached with a flat monolayer morphology while those cultured on surfaces having 115 μm‐sized pores exhibited a round 3D morphology. The cells also showed more in‐vivo like behavior on the porous surface by exhibiting significantly higher basal enzymatic activity and expressing higher levels of several drug metabolism‐related genes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40181.
Acrylate–vinylidene chloride copolymers derived from corresponding water‐borne latexes: Influence of acrylate units on their potential as heavy‐duty anticorrosive coating materials
Authors: Fu Ce , Qin Hong‐Wei , Ben Hai‐Jie , Han Jing , Cui Wen‐Zhu , Cheng Fa , Chen Yu 
Published: November 2013

AbstractA series of aqueous latexes with solid contents of 56%–59% were synthesized by binary emulsion copolymerization of vinylidene chloride (VDC) with an acrylate, namely methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), hexyl acrylate (HA), or 2‐ethylhexyl acrylate (EHA). Differential scanning calorimetry (DSC) and Fourier‐transform infrared (FTIR) spectroscopy showed that the acrylate units with short ester side‐chains, such as MA and EA, made the copolymers hard and the crystallization tendency of their PVDC segments was reduced. Hydrophobic acrylates with relatively long ester groups, such as HA and EHA, gave flexible copolymers, and favored the crystallization of their PVDC segments. BA endowed the copolymers with medium flexibility and crystallization tendency. As coating materials, the copolymers bearing MA and EA adhered poorly to the tinplate before or after 100 hr of salt‐spray corrosion, whereas those bearing BA, HA, or EHA showed good adhesion to tinplate when they had little or no crystallinity. After 100 hr of salt‐spray corrosion, only BA–VDC80, containing 80% VDC, retained both excellent adhesion to metal and excellent barrier performance. Further study demonstrated that BA–VDC80 could protect tinplate from rusting for at least 250 hr under harsh salt‐spray corrosion. Scanning electron microscopy, FTIR‐attenuated total reflectance spectroscopy and DSC were used to evaluate the corroded BA–VDC80 film. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40192.
Enantiomerization Pathway and Atropochiral Stability of the BINAP Ligand: A Density Functional Theory Study
Authors: Sanz García Juan , Lepetit Christine , Canac Yves , Chauvin Remi , Boggio‐Pasqua Martial 
Published: November 2013

AbstractA theoretical study of the enantiomerization pathway of BINAP, the paradigm of atropochiral ligands in asymmetric organometallic catalysis, is reported. Density functional theory was used with the B3PW91 functional and the 6‐31G(d,p) basis set. The calculation level was validated through the study of the syn and anti enantiomerization pathways of the 1,1′‐binaphthyl reference for which the enantiomerization barrier was calculated to be in good agreement with experimental data. Calculations were then performed on BINAP itself using the same level of theory, and showed that its enantiomerization mechanism follows the syn route through a concerted, yet highly asynchronous, all‐chiral process. The enantiomerization barrier was computed at 213 kJ mol−1 and proved little sensitive to the functional or to the basis set used, with values always larger than 200 kJ mol−1. The configurational stability of BINAP was finally characterized by a computed Oki’s racemization temperature of 491 °C.
Dehydrogenative Lactonization of Diols in Aqueous Media Catalyzed by a Water‐Soluble Iridium Complex Bearing a Functional Bipyridine Ligand
Authors: Fujita Ken‐ichi , Ito Wataru , Yamaguchi Ryohei 
Published: November 2013

AbstractA new catalytic system for the dehydrogenative lactonization of a variety of benzylic and aliphatic diols in aqueous media was developed. By using a water‐soluble, dicationic iridium catalyst bearing 6,6′‐dihydroxy‐2,2′‐bipyridine as a functional ligand, highly atom economical and environmentally benign synthesis of various lactones was achieved in good to excellent yields. Recovery and reuse of the catalyst were also accomplished by a simple phase separation and the recovered catalyst maintained its high activity at least until the fifth run.
Resistance‐Switchable Graphene Oxide–Polymer Nanocomposites for Molecular Electronics
Authors: Liu Gang , Chen Yu , Li Run‐Wei , Zhang Bin , Kang En‐Tang , Wang Cheng , Zhuang Xiaodong 
Published: November 2013

AbstractAs the thinnest material ever known in the universe, graphene has attracted a tremendous amount of attention in recent years. To switch graphene ON and OFF for memory devices, electroactive polymers, including polyaniline (PANI), polyvinylcarbazole (PVK), triphenylamine‐based polyazomethine (TPAPAM), polythiophene (PTh), and others, have been covalently bonded to graphene oxide (GO) to manipulate the processability and to engineer the molecular bandgap of the atomic carbon nanosheets. GO–PANI, GO–PVK, and GO–TPAPAM demonstrate promising bi‐stable resistive switching behaviors with small turn‐on voltages of less than 2.0 V, low power consumptions of 6.7 nW–221.4 μW, and large ON/OFF ratios exceeding 103. With advantages including miniaturized dimensions, mechanical flexibility, and the non‐exotic nature of the raw carbon material, GO–polymer nanocomposites promise to have great potential for next‐generation information‐storage applications.
Atom‐Efficient Gold(I)‐Chloride‐Catalyzed Synthesis of α‐Sulfenylated Carbonyl Compounds from Propargylic Alcohols and Aryl Thiols: Substrate Scope and Experimental and Theoretical Mechanistic Investigation
Authors: Biswas Srijit , Dahlstrand Christian , Watile Rahul A. , Kalek Marcin , Himo Fahmi , Samec Joseph S. M. 
Published: November 2013

AbstractGold(I)‐chloride‐catalyzed synthesis of α‐sulfenylated carbonyl compounds from propargylic alcohols and aryl thiols showed a wide substrate scope with respect to both propargylic alcohols and aryl thiols. Primary and secondary aromatic propargylic alcohols generated α‐sulfenylated aldehydes and ketones in 60–97 % yield. Secondary aliphatic propargylic alcohols generated α‐sulfenylated ketones in yields of 47–71 %. Different gold sources and ligand effects were studied, and it was shown that gold(I) chloride gave the highest product yields. Experimental and theoretical studies demonstrated that the reaction proceeds in two separate steps. A sulfenylated allylic alcohol, generated by initial regioselective attack of the aryl thiol on the triple bond of the propargylic alcohol, was isolated, evaluated, and found to be an intermediate in the reaction. Deuterium labeling experiments showed that the protons from the propargylic alcohol and aryl thiol were transferred to the 3‐position, and that the hydride from the alcohol was transferred to the 2‐position of the product. Density functional theory (DFT) calculations showed that the observed regioselectivity of the aryl thiol attack towards the 2‐position of propargylic alcohol was determined by a low‐energy, five‐membered cyclic protodeauration transition state instead of the strained, four‐membered cyclic transition state found for attack at the 3‐position. Experimental data and DFT calculations supported that the second step of the reaction is initiated by protonation of the double bond of the sulfenylated allylic alcohol with a proton donor coordinated to gold(I) chloride. This in turn allows for a 1,2‐hydride shift, generating the final product of the reaction.
Synthesis of Cyclobakuchiols A, B, and C by Using Conformation‐Controlled Stereoselective Reactions
Authors: Kawashima Hidehisa , Kaneko Yuki , Sakai Masahiro , Kobayashi Yuichi 
Published: November 2013

AbstractCyclohexanone with the pMeOC6H4 and CH2C(Me) substituents at the C3 and C4‐positions was prepared from (+)‐β‐pinene and converted to the allylic picolinate by a Masamune–Wittig reaction followed by reduction and esterification. Allylic substitution of this picolinate with Me2CuMgBr⋅MgBr2 in the presence of ZnI2 proceeded with γ regio‐ and stereoselectively to afford the quaternary carbon center on the cyclohexane ring with the CH2CH and Me groups in axial and equatorial positions, respectively. This product was converted to cyclobakuchiol A by demethylation and to cyclobakuchiol C by epoxidation of the CH2C(Me) group. For the synthesis of cyclobakuchiol B, the enantiomer of the above cyclohexanone derived from (−)‐β‐pinene was converted to the cyclohexane‐carboxylate, and the derived enolate was subjected to the reaction with CH2CHSOPh followed by sulfoxide elimination to afford the intermediate with the quaternary carbon center with MeOC(O) and CH2CH groups in axial and equatorial positions. The MeOC(O) group was transformed to the Me group to complete the synthesis of cyclobakuchiol B.
Distribution of neuronal KCC2a and KCC2b isoforms in mouse CNS
Authors: Markkanen Marika , Karhunen Tuula , Llano Olaya , Ludwig Anastasia , Rivera Claudio , Uvarov Pavel , Airaksinen Matti S. 
Published: November 2013

ABSTRACTThe neuronal K‐Cl cotransporter KCC2 maintains the low intracellular chloride concentration required for the fast hyperpolarizing actions of inhibitory neurotransmitters in mature central nervous system (CNS). The KCC2 gene produces two isoforms, KCC2a and KCC2b, that differ in their N‐termini. Increase of KCC2b in the cortex underlies the developmental shift in γ‐aminobutyric acid (GABA)ergic responses, whereas the physiological role of KCC2a is still poorly characterized. The two KCC2 isoforms show equal distribution in mouse brainstem neurons at birth; however their postnatal expression patterns, and the subcellular localization of KCC2a, have not yet been described. Here, we compared the pattern of KCC2a and KCC2b expression in different regions of postnatal mouse CNS by immunohistochemistry by using isoform‐specific antibodies. Tissue from KCC2a isoform‐specific knockout mice was used as a negative control. KCC2b expression increased postnatally and was widely expressed in adult brain. KCC2a immunoreactivity was low or absent in most parts of the adult cortex, hippocampus, thalamus, and cerebellar cortex. Both isoforms were widely present in the developing and mature hypothalamus, a large part of the brainstem, and the spinal cord. A notable exception was the lack of KCC2a staining in the brainstem auditory system. At the subcellular level, the isoforms were only partially colocalized. In neuronal somas, KCC2b immunoreactivity was concentrated at the plasma membrane, whereas KCC2a signal was not. Moreover, although both isoforms were expressed in microtubule‐associated protein (MAP)2‐positive dendrites, they appeared in non‐overlapping dendritic compartments. The results, together with those of previous studies, suggest that KCC2a and KCC2b have overlapping roles in neonatal neurons but presumably different roles in mature neurons. J. Comp. Neurol. 522:1897–1914, 2014. © 2013 Wiley Periodicals, Inc.