bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monotonic decrease of the zonal SST gradient of the equatorial Pacific as a function of CO2 concentration in CCSM3 and CCSM4
Authors: Yang Jun , Peltier Wm. Richard , Hu Yongyun 
Published: August 2016

AbstractThe west‐east sea surface temperature (SST) gradient in the equatorial Pacific Ocean is a key feature of Earth's climate. How this gradient responds to varying climatic forcing is a challenge to both climate theory and climate modeling. Using the coupled atmosphere‐ocean general circulation models, Community Climate System Model version 3 (CCSM3) and version 4 (CCSM4), we show that the zonal SST gradient is an almost monotonically decreasing function of atmospheric CO2 concentration (pCO2) across a wide range from 17.5 to 4576 ppmv. As pCO2 is increased, the optical depth of clouds over the western and central Pacific increases significantly, reflecting more insolation back to space, suppressing surface warming in this region and thereby reducing the zonal SST gradient. Ocean adjustment to a weakening of surface zonal winds is characterized by relaxations of the equatorial thermocline tilt, zonal surface currents, and ocean upwelling.
Cobalt(II)‐Catalyzed C−N Bond Formation: Synthesis of Aryl‐Substituted Imidazo[1,2‐a]pyridines
Authors: Rasheed Sk. , Rao Desaboini Nageswar , Das Parthasarathi 
Published: August 2016

AbstractA novel protocol for cobalt(II)‐catalyzed synthesis of 2‐arylimidazo[1,2‐a]pyridines and 3‐arylimidazo[1,2‐a]pyridines by direct C−N bond formation has been developed. This ligand‐ and base‐free oxidative process is regioselective and has good functional group tolerability. This annulation reaction probably involves a CoII/CoIII catalytic system and uses molecular oxygen (O2) as terminal oxidant. This cobalt catalyst system is simple and efficient, which holds potential for application in C−N bond formation.
Stereochemischer Verlauf der enzymatischen Synthese von Benzylsuccinat mit chiral markiertem Toluol
Authors: Seyhan Deniz , Friedrich Peter , Szaleniec Maciej , Hilberg Markus , Buckel Wolfgang , Golding Bernard T. , Heider Johann 
Published: August 2016

AbstractBenzylsuccinat‐Synthase ist ein Glycylradikal‐Enzym, das den anaeroben Toluolstoffwechsel durch Addition von Fumarat an die Methylgruppe des Toluols unter Bildung von (R)‐Benzylsuccinat einleitet. Zur Aufklärung der Frage, ob die Reaktion unter Retention oder Inversion der Konfiguration der Methylgruppe des Toluols verläuft, wurden beide Enantiomere von chiral markiertem Toluol synthetisiert. Diese Enantiomere, die jeweils alle drei H‐Isotope in ihren Methylgruppen enthalten, wurden zu Benzylsuccinaten umgesetzt. Aufgrund eines kinetischen Isotopeneffekts, der die Abstraktion von 1H von den Methylgruppen begünstigt, enthielten diese Produkte an ihren benzylischen C‐Atomen vorwiegend 2H und 3H. Die Analyse ihrer Konfiguration erfolgte durch CoA‐Thioester‐Synthese und stereospezifische Oxidation mit Enzymen, die am Abbau von Benzylsuccinat beteiligt sind. Die Analyse der Konfigurationen der Benzylsuccinat‐Isomere über den Verlust oder die Beibehaltung von Tritium zeigte, dass die Reaktion der beiden Enantiomere mit Fumarat unter Inversion der Konfiguration der Methylgruppen verläuft.
Isolation and Structure of Germylene‐Germyliumylidenes Stabilized by N‐Heterocyclic Imines
Authors: Ochiai Tatsumi , Szilvási Tibor , Franz Daniel , Irran Elisabeth , Inoue Shigeyoshi 
Published: August 2016

AbstractThe ditopic germanium complex FGe(NIPr)2Ge[BF4] (3[BF4]; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) is prepared by the reaction of the amino(imino)germylene (Me3Si)2NGeNIPr (1) with BF3⋅OEt2. This monocation is converted into the germylene‐germyliumylidene 3[BArF4] [ArF=3,5‐(CF3)2‐C6H3] by treatment with Na[BArF4]. The tetrafluoroborate salt 3[BF4] reacts with 2 equivalents of Me3SiOTf to give the novel complex (OTf)(GeNIPr)2[OTf] (4[OTf]), which affords 4[BArF4] and 4[Al(ORF)4] [RF=C(CF3)3] after anion exchange with Na[BArF4] or Ag[Al(ORF)4], respectively. The computational, as well as crystallographic study, reveals that 4+ has significant bis(germyliumylidene) dication character.
Highly Conductive Anion‐Exchange Membranes from Microporous Tröger's Base Polymers
Authors: Yang Zhengjin , Guo Rui , Malpass‐Evans Richard , Carta Mariolino , McKeown Neil B. , Guiver Michael D. , Wu Liang , Xu Tongwen 
Published: August 2016

AbstractThe development of polymeric anion‐exchange membranes (AEMs) combining high ion conductivity and long‐term stability is a major challenge for materials chemistry. AEMs with regularly distributed fixed cationic groups, based on the formation of microporous polymers containing the V‐shape rigid Tröger's base units, are reported for the first time. Despite their simple preparation, which involves only two synthetic steps using commercially available precursors, the polymers provide AEMs with exceptional hydroxide conductivity at relatively low ion‐exchange capacity, as well as a high swelling resistance and chemical stability. An unprecedented hydroxide conductivity of 164.4 mS cm−1 is obtained at a relatively a low ion‐exchange capacity of 0.82 mmol g−1 under optimal operating conditions. The exceptional anion conductivity appears related to the intrinsic microporosity of the charged polymer matrix, which facilitates rapid anion transport.
Dispersion and Hydrogen Bonding Rule: Why the Vaporization Enthalpies of Aprotic Ionic Liquids Are Significantly Larger than those of Protic Ionic liquids
Authors: Zaitsau Dzmitry H. , Emel'yanenko Vladimir N. , Stange Peter , Schick Christoph , Verevkin Sergey P. , Ludwig Ralf 
Published: August 2016

AbstractIt is well known that gas‐phase experiments and computational methods point to the dominance of dispersion forces in the molecular association of hydrocarbons. Estimates or even quantification of these weak forces are complicated due to solvent effects in solution. The dissection of interaction energies and quantification of dispersion interactions is particularly challenging for polar systems such as ionic liquids (ILs) which are characterized by a subtle balance between Coulomb interactions, hydrogen bonding, and dispersion forces. Here, we have used vaporization enthalpies, far‐infrared spectroscopy, and dispersion‐corrected calculations to dissect the interaction energies between cations and anions in aprotic (AILs), and protic (PILs) ionic liquids. It was found that the higher total interaction energy in PILs results from the strong and directional hydrogen bonds between cation and anion, whereas the larger vaporization enthalpies of AILs clearly arise from increasing dispersion forces between ion pairs.
Synthesis of polyamide 6/11 copolymers and their use as matrix polymer in wood‐plastic composites
Authors: Zierdt Patrick , Mitzner Elke , Gomoll André , Theumer Torsten , Lieske Antje 
Published: August 2016

ABSTRACTThe goal of this study was to investigate the synthesis and the resulting thermal, rheological, and mechanical properties of polyamide 6/11 copolymers (PA 6/11) as a function of their composition and to further investigate their usability as matrix polymers for wood‐plastic composites (WPC). A significant composition dependency of the melting temperature was found due to the hindered crystallization of the PA 6/11 copolymers with increasing content of the minor component. In result, the lowest melting temperature of the copolymers was measured at 120 °C for 40 wt % of ɛ‐caprolactam (PA 6/11‐40/60) by DSC analysis. Due to its low melting point and feasible mechanical properties, a copolyamide with 70 wt % of ɛ‐caprolactam (PA 6/11‐70/30) was chosen as matrix material for the processing of WPC. Incorporation of 30 wt % of wood fibers into PA 6/11‐70/30 caused a significant increase in tensile modulus and a decrease in tensile strength and strain at break. However, the processed WPC still showed an exceptional ductility with a strain at break of 15 to 20%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44155.
Effect of grafting yield and molecular weight of m‐TMI‐grafted‐PP on the mechanical properties of wood fiber filled polypropylene composites
Authors: Kale Amey , Raghu N. , Natu H.P. , Aggarwal Pankaj , Chauhan Shakti 
Published: August 2016

ABSTRACTm‐Isopropenyl‐α, α‐dimethylbenzyl isocyanate (m‐TMI) was grafted on isotactic polypropylene (PP) using di‐cumyl peroxide as a reaction initiator under varying reaction conditions to yield m‐TMI‐g‐PP coupling agent with four sets of grafting yield and molecular weight. Grafting yield of the synthesized m‐TMI‐g‐PP were 1.80%, 2.01%, 9.05%, and 8.86% and molecular weight of the corresponding grafted polymer were 129,225; [Correction made here after initial online publication.] 187,240; 124,130; and 180,838, respectively. Rubberwood flour reinforced polypropylene composites were prepared using these coupling agents and tested for mechanical properties. m‐TMI‐g‐PP coupling agent with 9.09% grafting and 124230 Mw was found to give the highest tensile and flexural strengths. Flexural modulus of the coupled composites was higher than uncoupled composites. Interfacial region of the composites characterized by scanning electron microscope (SEM) suggest effective wetting of fiber by PP in the case of coupled composites. The effect of fiber loading on composites indicates continuous increment in tensile and flexural strengths in coupled composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44196.
Screening anti‐allergic components of Astragali Radix using LAD2 cell membrane chromatography coupled online with UHPLC‐ESI‐MS/MS method
Authors: Lv Yanni , Sun Yueming , Fu Jia , Kong Liyun , Han Shengli 
Published: August 2016

AbstractHuangqi (Astragali Radix), a traditional Chinese herb, is widely used in clinical therapy in China. In addition, an anti‐allergic effect of constituents in Huangqi has been reported in the scientific literature. In the present study, cell membrane chromatography coupled online with UHPLC‐ESI‐MS/MS method was developed to screen, analyze and identify the anti‐allergic components of Huangqi. The Laboratory of Allergic Disease 2 (LAD2) cell was used to establish cell membrane chromatography, which was combined with UHPLC‐ESI‐MS/MS. The coupled system was then used to screen anti‐allergic components from Huangqi. Effects of active components were verified by histamine release assay. A component retained on the LAD2 cell membrane chromatography was identified as formononetin. Bioactivity of formononetin was investigated by histamine release assay in LAD2 cells, and it was found that formononetin could inhibit histamine release in a dose‐dependent manner from 1 to 100 μm. The LAD2 cell membrane chromatography online with UHPLC‐ESI‐MS/MS method is an effective technique for screening the anti‐allergic components of Huangqi.
Structural Impact of Single Ribonucleotide Residues in DNA
Authors: Evich Marina , Spring‐Connell Alexander M. , Storici Francesca , Germann Markus W. 
Published: August 2016

AbstractSingle ribonucleotide intrusions represent the most common nonstandard nucleotide type found incorporated in genomic DNA, yet little is known of their structural impact. This lesion incurs genomic instability in addition to affecting the physical properties of the DNA. To probe for structural and dynamic effects of single ribonucleotides in various sequence contexts—AxC, CxG, and GxC, where x=rG or dG—we report the structures of three single‐ribonucleotide‐containing DNA duplexes and the corresponding DNA controls. The lesion subtly and locally perturbs the structure asymmetrically on the 3′ side of the lesion in both the riboguanosine‐containing and the complementary strand of the duplex. The perturbations are mainly restricted to the sugar and phosphodiester backbone. The ribose and 3′‐downstream deoxyribose units are predominately in N‐type conformation; backbone torsion angles ϵ and/or ζ of the ribonucleotide or upstream deoxyribonucleotide are affected. Depending on the flanking sequences, the C2′−OH group forms hydrogen bonds with the backbone, 3′‐neighboring base, and/or sugar. Interestingly, even in similar purine‐rG‐pyrimidine environments (A‐rG‐C and G‐rG‐C), a riboguanosine unit affects DNA in a distinct manner and manifests different hydrogen bonds, which makes generalizations difficult.
Importance of the Anchor Group Position (Para versus Meta) in Tetraphenylmethane Tripods: Synthesis and Self‐Assembly Features
Authors: Lindner Marcin , Valášek Michal , Homberg Jan , Edelmann Kevin , Gerhard Lukas , Wulfhekel Wulf , Fuhr Olaf , Wächter Tobias , Zharnikov Michael , Kolivoška Viliam , Pospíšil Lubomír , Mészáros Gábor , Hromadová Magdaléna , Mayor Marcel 
Published: August 2016

AbstractThe efficient synthesis of tripodal platforms based on tetraphenylmethane with three acetyl‐protected thiol groups in either meta or para positions relative to the central sp3 carbon for deposition on Au (111) surfaces is reported. These platforms are intended to provide a vertical arrangement of the substituent in position 4 of the perpendicular phenyl ring and an electronic coupling to the gold substrate. The self‐assembly features of both derivatives are analyzed on Au (111) surfaces by low‐temperature ultra‐high‐vacuum STM, high‐resolution X‐ray photoelectron spectroscopy, near‐edge X‐ray absorption fine structure spectroscopy, and reductive voltammetric desorption studies. These experiments indicated that the meta derivative forms a well‐ordered monolayer, with most of the anchoring groups bound to the surface, whereas the para derivative forms a multilayer film with physically adsorbed adlayers on the chemisorbed para monolayer. Single‐molecule conductance values for both tripodal platforms are obtained through an STM break junction experiment.
Aromatic Cluster Sensor of Protein Folding: Near‐UV Electronic Circular Dichroism Bands Assigned to Fold Compactness
Authors: Farkas Viktor , Jákli Imre , Tóth Gábor K. , Perczel András 
Published: August 2016

AbstractBoth far‐ and near‐UV electronic circular dichroism (ECD) spectra have bands sensitive to thermal unfolding of Trp and Tyr residues containing proteins. Beside spectral changes at 222 nm reporting secondary structural variations (far‐UV range), Lbbands (near‐UV range) are applicable as 3D‐fold sensors of protein's core structure. In this study we show that both Lb(Tyr) and Lb(Trp) ECD bands could be used as sensors of fold compactness. ECD is a relative method and thus requires NMR referencing and cross‐validation, also provided here. The ensemble of 204 ECD spectra of Trp‐cage miniproteins is analysed as a training set for “calibrating” Trp↔Tyr folded systems of known NMR structure. While in the far‐UV ECD spectra changes are linear as a function of the temperature, near‐UV ECD data indicate a non‐linear and thus, cooperative unfolding mechanism of these proteins. Ensemble of ECD spectra deconvoluted gives both conformational weights and insight to a protein folding↔unfolding mechanism. We found that the Lb293band is reporting on the 3D‐structure compactness. In addition, the pure near‐UV ECD spectrum of the unfolded state is described here for the first time. Thus, ECD folding information now validated can be applied with confidence in a large thermal window (5≤T≤85 °C) compared to NMR for studying the unfolding of Trp↔Tyr residue pairs. In conclusion, folding propensities of important proteins (RNA polymerase II, ubiquitin protein ligase, tryptase‐inhibitor etc.) can now be analysed with higher confidence.
Surface Enhanced Raman Scattering and Gated Materials for Sensing Applications: The Ultrasensitive Detection of Mycoplasma and Cocaine
Authors: Oroval Mar , Coronado‐Puchau Marc , Langer Judith , Sanz‐Ortiz Marta Norah , Ribes Ángela , Aznar Elena , Coll Carmen , Marcos María Dolores , Sancenón Félix , Liz‐Marzán Luis M. , Martínez‐Máñez Ramón 
Published: August 2016

AbstractWe present herein a novel combination of gated mesoporous silica nanoparticles (MSNs) and surface‐enhanced Raman scattering (SERS) for sensing applications. As a proof‐of‐concept, we show the design of a system comprising MSNs loaded with crystal violet (CV), a molecule with high Raman cross section acting as SERS reporter, and capped with either a suitable DNA sequence for the detection of Mycoplasma genomic DNA or with an aptamer that selectively coordinates cocaine. In both cases the presence of the corresponding target analyte in solution (i.e., genomic DNA or cocaine) resulted in the release of CV. CV delivery was detected by SERS upon adsorption on gold nanotriangles (AuNTs), which display an efficient electromagnetic field enhancement and a high colloidal stability. By using this novel procedure a limit of detection of at least 30 copies DNA per μL was determined for the detection of Mycoplasma genomic DNA, whereas cocaine was detected at concentrations as low as 10 nm.
Absolute Configuration from Different Multifragmentation Pathways in Light‐Induced Coulomb Explosion Imaging
Authors: Pitzer Martin , Kastirke Gregor , Kunitski Maksim , Jahnke Till , Bauer Tobias , Goihl Christoph , Trinter Florian , Schober Carl , Henrichs Kevin , Becht Jasper , Zeller Stefan , Gassert Helena , Waitz Markus , Kuhlins Andreas , Sann Hendrik , Sturm Felix , Wiegandt Florian , Wallauer Robert , Schmidt Lothar Ph. H. , Johnson Allan S. , Mazenauer Manuel , Spenger Benjamin , Marquardt Sabrina , Marquardt Sebastian , Schmidt‐Böcking Horst , Stohner Jürgen , Dörner Reinhard , Schöffler Markus , Berger Robert 
Published: August 2016

AbstractThe front cover artwork is provided by the groups of Reinhard Dörner (University of Frankfurt), Robert Berger (University of Marburg) and Jürgen Stohner (Zurich University for Applied Sciences, Wädenswil). The image shows how a single X‐ray photon from a synchrotron source induces the Coulomb Explosion of a prototypical chiral molecule (CHBrClF), allowing to distinguish the enantiomers and determine the absolute configuration. Read the full text of the article at 10.1002/cphc.201501118.
Microchemical Pen: An Open Microreactor for Region‐Selective Surface Modification
Authors: Mao Sifeng , Sato Chiho , Suzuki Yuma , Yang Jianmin , Zeng Hulie , Nakajima Hizuru , Yang Ming , Lin Jin‐Ming , Uchiyama Katsumi 
Published: August 2016

AbstractVarious micro surface‐modification approaches including photolithography, dip‐pen lithography and ink‐jet systems have been developed and used to extend the functionalities of solid surfaces. While those approaches work in the “open space”, push–pull systems which work in solutions have recently drawn considerable attention. However, the confining flows performed by push–pull systems have realized only the dispense process, while microscale, region‐selective chemical reactions have remained unattainable. This study reports a microchemical pen that enables region‐selective chemical reactions for the micro surface modification/patterning. The chemical pen is based on the principle of microfluidic laminar flows and the resulting mixing of reagents by the mutual diffusion. The tiny diffusion layer performs as the working region. This report represents the first demonstration of an open microreactor in which two different reagents react on a real solid sample. The multifunctional characteristics of the microchemical pen are confirmed by different types of reactions in many research areas, including inorganic chemistry, polymer science, electrochemistry and biological sample treatment.
Evaluation of Life Events in Major Depression: Assessing Negative Emotional Bias
Authors: Girz Laura , Driver‐Linn Erin , Miller Gregory A. , Deldin Patricia J. 
Published: August 2016

BackgroundOverly negative appraisals of negative life events characterize depression but patterns of emotion bias associated with life events in depression are not well understood. The goal of this paper is to determine under which situations emotional responses are stronger than expected given life events and which emotions are biased.MethodsDepressed (n = 16) and non‐depressed (n = 14) participants (mean age = 41.4 years) wrote about negative life events involving their own actions and inactions, and rated the current emotion elicited by those events. They also rated emotions elicited by someone else's actions and inactions. These ratings were compared with evaluations provided by a second, ‘benchmark’ group of non‐depressed individuals (n = 20) in order to assess the magnitude and direction of possible biased emotional reactions in the two groups.ResultsParticipants with depression reported greater anger and disgust than expected in response to both actions and inactions, whereas they reported greater guilt, shame, sadness, responsibility and fear than expected in response to inactions. Relative to non‐depressed and benchmark participants, depressed participants were overly negative in the evaluation of their own life events, but not the life events of others.ConclusionA standardized method for establishing emotional bias reveals a pattern of overly negative emotion only in depressed individuals' self‐evaluations, and in particular with respect to anger and disgust, lending support to claims that major depressives' evaluations represent negative emotional bias and to clinical interventions that address this bias. Copyright © 2016 John Wiley & Sons, Ltd.
Enzymatic assays for detecting lactose and sucrose in urine to reveal intravenous drug abuse with emphasis on buprenorphine
Authors: Keltanen T. , Mariottini C. , Walta A. M. , Rahikainen A. L. , Ojanperä I. 
Published: August 2016

Buprenorphine and methadone are commonly used medications for opioid maintenance treatment (OMT), using sublingual and oral administration, respectively. Although beneficial for OMT, these drugs can also be abused by intravenous administration. In intravenous abuse cases, the adjuvants lactose and sucrose are excreted in urine without hydrolysis to monosaccharides, since there are no disaccharidases in the blood.We validated enzymatic methods for the analysis of lactose and sucrose in urine. The analytical performance of both assays was considered appropriate for detecting intravenous drug abuse. The principle was proven by analyzing 93 postmortem (PM) urine samples for lactose, following comprehensive toxicological drug screening. In addition, 32 clinical urine samples from potential drug abusers were analyzed to assess the effect of PM changes on the assay. The mean level of lactose was low in clinical samples and relatively low in PM samples in which no drugs were found. Markedly elevated levels were seen in many of the buprenorphine positive samples, suggesting intravenous administration.Enzymatic methods could provide a simple and cost effective way to assess the intravenous administration of OMT drugs or drugs of abuse. Very high levels of glucose in urine may interfere with the assays. Furthermore, other causes for elevated urine disaccharides, such as hypolactasia and increased intestinal permeability, need to be considered in the interpretation of the results. Copyright © 2016 John Wiley & Sons, Ltd.