bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Signature of Southern Hemisphere Atmospheric Circulation Patterns in Antarctic Precipitation
Authors: Marshall Gareth J. , Thompson David W. J. , van den Broeke Michiel R. 
Published: November 2017

AbstractWe provide the first comprehensive analysis of the relationships between large‐scale patterns of Southern Hemisphere climate variability and the detailed structure of Antarctic precipitation. We examine linkages between the high spatial resolution precipitation from a regional atmospheric model and four patterns of large‐scale Southern Hemisphere climate variability: the southern baroclinic annular mode, the southern annular mode, and the two Pacific‐South American teleconnection patterns. Variations in all four patterns influence the spatial configuration of precipitation over Antarctica, consistent with their signatures in high‐latitude meridional moisture fluxes. They impact not only the mean but also the incidence of extreme precipitation events. Current coupled‐climate models are able to reproduce all four patterns of atmospheric variability but struggle to correctly replicate their regional impacts on Antarctic climate. Thus, linking these patterns directly to Antarctic precipitation variability may allow a better estimate of future changes in precipitation than using model output alone.
An Empirical Modification of the Force Field Approach to Describe the Modulation of Galactic Cosmic Rays Close to Earth in a Broad Range of Rigidities
Authors: Gieseler J. , Heber B. , Herbst K. 
Published: November 2017

AbstractOn their way through the heliosphere, galactic cosmic rays (GCRs) are modulated by various effects before they can be detected at Earth. This process can be described by the Parker equation, which calculates the phase space distribution of GCRs depending on the main modulation processes: convection, drifts, diffusion, and adiabatic energy changes. A first‐order approximation of this equation is the force field approach, reducing it to a one‐parameter dependency, the solar modulation potential ϕ. Utilizing this approach, it is possible to reconstruct ϕ from ground‐based and spacecraft measurements. However, it has been shown previously that ϕ depends not only on the local interstellar spectrum (LIS) but also on the energy range of interest. We have investigated this energy dependence further, using published proton intensity spectra obtained by PAMELA and heavier nuclei measurements from IMP‐8 and ACE/CRIS. Our results show severe limitations at lower energies including a strong dependence on the solar magnetic epoch. Based on these findings, we will outline a new tool to describe GCR proton spectra in the energy range from a few hundred MeV to tens of GeV over the last solar cycles. In order to show the importance of our modification, we calculate the global production rates of the cosmogenic radionuclide 10Be which is a proxy for the solar activity ranging back thousands of years.
Chi‐Squared Tests: Basics
Authors: Koch Gary G. , Wiener Laura E. 
Published: November 2017

AbstractThis article discusses the underlying principles for chi‐squared tests and provides an overview for the scope of their applications. Specific topics are as follows: (i) the test for specified variance of univariate normal random variables; (ii) approximate randomization tests for hypotheses of no association of response variables with a set of groups; (iii) approximate tests for hypotheses pertaining to parameters in assumed likelihood functions. For these topics, the chi‐squared test statistics are quadratic forms, and they address departures from randomness for a vector of differences between observed values of estimates of interest and their expected values under corresponding null hypotheses, relative to the inverse of the applicable covariance matrix. It is of note that, sufficient sample size is necessary for (ii) and (iii) to support an approximately chi‐squared distribution for the test statistic with degrees of freedom equal to the dimension of the vector that is addressed.
Genetic Manipulation of Leaf Senescence
Authors: Guo Yongfeng , Gan Susheng 
Published: November 2017

Abstract
The sections in this article are

Introduction

Strategies of Manipulating Leaf Senescence

IPT
‐Based Transgenic Techniques for Manipulation of Cytokinin Production

Development of the
SAG12
‐

IPT

Autoregulatory Cytokinin Production System

Use of the
SAG12
‐

IPT

to Manipulate Senescence in Crops

Other Strategies for Manipulation of Leaf Senescence

Closing Remarks

Acknowledgment
Genetic Control of Seed Development and Seed Mass
Authors: Ohto Masa‐aki , Stone Sandra L. , Harada John J. 
Published: November 2017

AbstractThe sections in this article areIntroductionOverview of Seed Development in AngiospermsGenetic Control of Embryo DevelopmentGenetic Control of Endosperm DevelopmentGenetic Aspects of Testa DevelopmentControl of Seed MassPerspectiveAcknowledgements
Seed Coat Development and Dormancy
Authors: Debeaujon Isabelle , Lepiniec Loïc , Pourcel Lucille , Routaboul Jean‐Marc 
Published: November 2017

AbstractThe sections in this article areIntroductionDevelopment and Anatomy of the Seed CoatRole of the Seed Coat in Seed Dormancy and GerminationLink between Seed Coat‐Imposed Dormancy and LongevityConcluding Remarks
Lipid Metabolism in Seed Dormancy
Authors: Penfield Steven , Pinfield‐Wells Helen , Graham Ian A. 
Published: November 2017

AbstractThe sections in this article areIntroductionMetabolic Pathways forTAGBreakdown and Conversion to SucroseLipid Metabolism and Seed DormancyMechanisms for the Involvement ofβ‐Oxidation in Dormancy ReleaseConclusions
Strategies for the Investigation of Protein–Protein Interactions in Plants
Authors: Braun Hans‐Peter , Schmitz Udo K. 
Published: November 2017

Abstract
The sections in this article are

Summary

Introduction

Biochemical Procedures to Characterize Protein–Protein Interactions

Genetic Procedures to Characterize Protein–Protein Interactions

Cytological Procedures to Characterize Protein–Protein Interactions

Outlook

Acknowledgements
A Multiparameter pH‐Sensitive Nanodevice Based on Plasmonic Nanopores
Authors: Liu Hailing , Jiang Qiucen , Pang Jie , Jiang Zeyu , Cao Jiao , Ji Lina , Xia Xinghua , Wang Kang 
Published: November 2017

AbstractWith controllable mass transfer and special optical properties, plasmonic nanopores may be applied as a nanodevice and possibly create a new generation of single molecule detection technique based on plasmon‐enhanced spectra. In the present study, gold nanoparticles self‐assemble into a gold porous sphere (GPS) on the tip of a glass nanopipette with the help of i‐motif DNA thiolated by both ends as linker molecules. The gaps among neighboring gold nanoparticles are considered as plasmonic nanopores. The size of the formed nanopores can be tuned by the folded–unfolded conformational change of i‐motif DNA upon pH adjustment from 4.5 to 7.0. Based on its tunable structural property, the GPS shows reversible changes in ionic current, potential, and surface‐enhanced Raman scattering signal. The GPS is further used to probe regional pH in single cells. The successful application of GPS in multiparameter pH probing and single cell analysis suggests that the new physical properties of the self‐assembled plasmonic nanopores can be used for fabricating multiple types of nanodevices and nanosensors.
Microenvironmental Stiffness of 3D Polymeric Structures to Study Invasive Rates of Cancer Cells
Authors: Lemma Enrico Domenico , Spagnolo Barbara , Rizzi Francesco , Corvaglia Stefania , Pisanello Marco , De Vittorio Massimo , Pisanello Ferruccio 
Published: November 2017

AbstractCells are highly dynamic elements, continuously interacting with the extracellular environment. Mechanical forces sensed and applied by cells are responsible for cellular adhesion, motility, and deformation, and are heavily involved in determining cancer spreading and metastasis formation. Cell/extracellular matrix interactions are commonly analyzed with the use of hydrogels and 3D microfabricated scaffolds. However, currently available techniques have a limited control over the stiffness of microscaffolds and do not allow for separating environmental properties from biological processes in driving cell mechanical behavior, including nuclear deformability and cell invasiveness. Herein, a new approach is presented to study tumor cell invasiveness by exploiting an innovative class of polymeric scaffolds based on two‐photon lithography to control the stiffness of deterministic microenvironments in 3D. This is obtained by fine‐tuning of the laser power during the lithography, thus locally modifying both structural and mechanical properties in the same fabrication process. Cage‐like structures and cylindric stent‐like microscaffolds are fabricated with different Young's modulus and stiffness gradients, allowing obtaining new insights on the mechanical interplay between tumor cells and the surrounding environments. In particular, cell invasion is mostly driven by softer architectures, and the introduction of 3D stiffness “weak spots” is shown to boost the rate at which cancer cells invade the scaffolds. The possibility to modulate structural compliance also allowed estimating the force distribution exerted by a single cell on the scaffold, revealing that both pushing and pulling forces are involved in the cell–structure interaction. Overall, exploiting this method to obtain a wide range of 3D architectures with locally engineered stiffness can pave the way for unique applications to study tumor cell dynamics.
Anion‐Regulated Selective Generation of Cobalt Sites in Carbon: Toward Superior Bifunctional Electrocatalysis
Authors: Wan Gang , Yang Ce , Zhao Wanpeng , Li Qianru , Wang Ning , Li Tao , Zhou Hua , Chen Hangrong , Shi Jianlin 
Published: November 2017

AbstractThe introduction of active transition metal sites (TMSs) in carbon enables the synthesis of noble‐metal‐free electrocatalysts for clean energy conversion applications; however, there are often multiple existing forms of TMSs, which are of different natures and catalytic models. Regulating the evolution of distinctive TMSs is highly desirable but remains challenging to date. Anions, as essential elements involved in the synthesis, have been totally neglected previously in the construction of TMSs. Herein, the effects of anions on the creation of different types of TMSs are investigated for the first time. It is found that the active cobalt–nitrogen sites tend to be selectively constructed on the surface of N‐doped carbon by using chloride, while metallic cobalt nanoparticles encased in protective graphite layers are the dominant forms of cobalt species with nitrate ions. The obtained catalysts demonstrate cobalt‐sites‐dependent activity for oxygen reduction reaction and hydrogen evolution reaction in acidic media. The remarkably enhanced catalytic activities approaching that of benchmark Pt/C in an acidic medium have been obtained on the catalyst dominated with cobalt–nitrogen sites, confirmed by the advanced spectroscopic characterization. This finding demonstrates a general paradigm of anion‐regulated evolution of distinctive TMSs, providing a new pathway for enhancing performances of various targeted reactions related with TMSs.
A Thermophilic Tetramolecular G‐Quadruplex/Hemin DNAzyme
Authors: Guo Yuehua , Chen Jielin , Cheng Mingpan , Monchaud David , Zhou Jun , Ju Huangxian 
Published: November 2017

AbstractThe quadruplex‐based DNAzyme system is one of the most useful artificial enzymes or catalysts; their unique properties make them reliable alternatives to proteins for performing catalytic transformation. The first prototype of a thermally stable DNAzyme system is presented. This thermophilic DNAzyme is capable of oxidizing substrates at high temperatures (up to 95 °C) and long reaction times (up to 18 h at 75 °C). The catalytic activity of the DNAzymes were investigated with the standard peroxidase‐mimicking oxidation of 2,2′‐azino‐bis(3‐ethylbenzothiozoline‐6‐sulfonic acid) (ABTS) by H2O2. The step‐by‐step design of this unique heat‐activated G‐quadruplex/hemin catalyst, including the modification of adenines at both ends of G‐tracts, the choice of cation, and its concentration for DNAzyme stabilization, is described. This work investigates thoroughly the molecular basis of these catalytic properties and provides an example of an industrially relevant application.
Ligand‐controlled Regiodivergent C−H Alkenylation of Pyrazoles and its Application to the Synthesis of Indazoles
Authors: Kim Hyun Tae , Ha Hyeri , Kang Geunhee , Kim Og Soon , Ryu Ho , Biswas Abul Kalam , Lim Sang Min , Baik Mu‐Hyun , Joo Jung Min 
Published: November 2017

AbstractRegioselective C4‐, C5‐, and di‐alkenylations of pyrazoles were achieved. An electrophilic Pd catalyst generated by trifluoroacetic acid (TFA) and 4,5‐diazafluoren‐9‐one (DAF) leads to C4‐alkenylation, whereas KOAc and mono‐protected amino acid (MPAA) ligand Ac‐Val‐OH give C5‐alkenylation. A combination of palladium acetate, silver carbonate, and pivalic acid affords dialkenylation products. Annulation through sequential alkenylation, thermal 6π‐electrocyclization, and oxidation gives functionalized indazoles. This comprehensive strategy greatly expands the range of readily accessible pyrazole and indazole derivatives, enabling useful regiodivergent C−H functionalization of pyrazoles and other heteroaromatic systems.
A High‐Resolution Crystal Structure that Reveals Molecular Details of Target Recognition by the Calcium‐Dependent Lipopeptide Antibiotic Laspartomycin C
Authors: Kleijn Laurens H. J. , Vlieg Hedwich C. , Wood Thomas M. , Sastre Toraño Javier , Janssen Bert J. C. , Martin Nathaniel I. 
Published: November 2017

AbstractThe calcium‐dependent antibiotics (CDAs) are an important emerging class of antibiotics. The crystal structure of the CDA laspartomycin C in complex with calcium and the ligand geranyl‐phosphate at a resolution of 1.28 Å is reported. This is the first crystal structure of a CDA bound to its bacterial target. The structure is also the first to be reported for an antibiotic that binds the essential bacterial phospholipid undecaprenyl phosphate (C55‐P). These structural insights are of great value in the design of antibiotics capable of exploiting this unique bacterial target.
L3C3P3: Tricarbontriphosphide Tricyclic Radicals and Cations Stabilized by Cyclic (alkyl)(amino)carbenes
Authors: Li Zhongshu , Hou Yuanfeng , Li Yaqi , Hinz Alexander , Harmer Jeffrey R. , Su Cheng‐Yong , Bertrand Guy , Grützmacher Hansjörg 
Published: November 2017

AbstractAlkynes usually oligomerize to give rings with a conjugated π‐electron system. In contrast, phosphaalkynes, R−C≡P, frequently give compounds with polycyclic structures, which are thermodynamically more stable than the corresponding π‐conjugated isomers. The syntheses of the first C3P3 tricyclic compounds are reported with either radical or cationic ground states stabilized by cyclic (alkyl)(amino)carbenes (CAACs). These compounds may be considered as examples of tricarbontriphosphide coordinated by carbenes and are likely formed via trimerization of the corresponding mono‐radicals CAAC‐CP.. The mechanism for the formation of these tricarbontriphosphide radicals has been rationalized by a combination of experiments and DFT calculations.
Solid‐State Structure of Protonated Ketones and Aldehydes
Authors: Stuart Daniel , Wetmore Stacey D. , Gerken Michael 
Published: November 2017

AbstractProtonated carbonyl compounds have been invoked as intermediates in many acid‐catalyzed organic reactions. To gain key structural and electronic data about such intermediates, oxonium salts derived from five representative examples of ketones and aldehydes are synthesized in the solid state, and characterized by X‐ray crystallography and Raman spectroscopy for the first time. DFT calculations were carried out on the cations in the gas phase. Whereas an equimolar reaction of the carbonyl compounds, acetone, cyclopentanone, adamantanone, and acetaldehyde, with SbF5 in anhydrous HF yielded mononuclear oxonium cations, the same stoichiometry in a reaction with benzaldehyde resulted in formation of a hemiprotonated, hydrogen‐bridged dimeric cation. Hemiprotonated acetaldehyde was obtained when a 2:1 ratio of aldehyde and SbF5 was used. Experimental and NBO analyses quantify the significant increase in electrophilicity of the oxonium cations compared to that of the parent ketones/aldehydes.
1,1‐Hydroboration and a Borane Adduct of Diphenyldiazomethane: A Potential Prelude to FLP‐N2 Chemistry
Authors: Tang Connie , Liang Quiming , Jupp Andrew R. , Johnstone Timothy C. , Neu Rebecca C. , Song Datong , Grimme Stefan , Stephan Douglas W. 
Published: November 2017

AbstractDiphenyldiazomethane reacts with HB(C6F5)2 and B(C6F5)3, resulting in 1,1‐hydroboration and adduct formation, respectively. The hydroboration proceeds via a concerted reaction involving initial formation of the Lewis adduct Ph2CN2BH(C6F5)2. The highly sensitive adduct Ph2CN2(B(C6F5)3) liberates N2 and generates Ph2CB(C6F5)3. DFT computations reveal that formation of Ph2CN2B(C6F5)3 from carbene, N2, and borane is thermodynamically favourable, suggesting steric frustration could preclude carbene–borane adduct formation and affect FLP‐N2 capture.
Radical Copolymerization of Vinyl Ethers and Cyclic Ketene Acetals as a Versatile Platform to Design Functional Polyesters
Authors: Tardy Antoine , Honoré Jean‐Claude , Tran Johanna , Siri Didier , Delplace Vianney , Bataille Isabelle , Letourneur Didier , Perrier Josette , Nicoletti Cendrine , Maresca Marc , Lefay Catherine , Gigmes Didier , Nicolas Julien , Guillaneuf Yohann 
Published: November 2017

AbstractFree‐radical copolymerization of cyclic ketene acetals (CKAs) and vinyl ethers (VEs) was investigated as an efficient yet simple approach for the preparation of functional aliphatic polyesters. The copolymerization of CKA and VE was first predicted to be quasi‐ideal by DFT calculations. The theoretical prediction was experimentally confirmed by the copolymerization of 2‐methylene‐1,3‐dioxepane (MDO) and butyl vinyl ether (BVE), leading to rMDO=0.73 and rBVE=1.61. We then illustrated the versatility of this approach by preparing different functional polyesters: 1) copolymers functionalized by fluorescent probes; 2) amphiphilic copolymers grafted with poly(ethylene glycol) (PEG) side chains able to self‐assemble into PEGylated nanoparticles; 3) antibacterial films active against Gram‐positive and Gram‐negative bacteria (including a multiresistant strain); and 4) cross‐linked bioelastomers with suitable properties for tissue engineering applications.
Cyclic Triimidazole Derivatives: Intriguing Examples of Multiple Emissions and Ultralong Phosphorescence at Room Temperature
Authors: Lucenti Elena , Forni Alessandra , Botta Chiara , Carlucci Lucia , Giannini Clelia , Marinotto Daniele , Pavanello Alessandro , Previtali Andrea , Righetto Stefania , Cariati Elena 
Published: November 2017

AbstractThe performance of solid luminogens depends on both their inherent electronic properties and their packing status. Intermolecular interactions have been exploited to achieve persistent room‐temperature phosphorescence (RTP) from organic molecules. However, the design of organic materials with bright RTP and the rationalization of the role of interchromophoric electronic coupling remain challenging tasks. Cyclic triimidazole has been shown to be a promising scaffold for such purposes owing to its crystallization‐induced room‐temperature ultralong phosphorescence (RTUP), which has been associated with H‐aggregation. Herein, we report three triimidazole derivatives as significant examples of multifaceted emission. In particular, dual fluorescence, RTUP, and phosphorescence from the molecular and supramolecular units were observed. H‐aggregation is responsible for the red RTUP, and Br substituents favor yellow molecular phosphorescence while halogen‐bonded Br⋅⋅⋅Br tetrameric units are involved in the blue‐green phosphorescence.
Organocatalytic Atroposelective Arylation of 2‐Naphthylamines as a Practical Approach to Axially Chiral Biaryl Amino Alcohols
Authors: Chen Ye‐Hui , Qi Liang‐Wen , Fang Fang , Tan Bin 
Published: November 2017

AbstractThe first phosphoric acid catalyzed direct arylation of 2‐naphthylamines with iminoquinones for the atroposelective synthesis of axially chiral biaryl amino alcohols has been developed. This reaction constitutes a highly functional‐group‐tolerant route for the rapid construction of enantioenriched axially chiral biaryl amino alcohols, and is a rare example of 2‐naphthylamines acting as nucleophiles in an organocatalytic enantioselective transformation. Furthermore, the products, which feature various halogen atoms, provide access to structurally diverse axially chiral amino alcohols through further transformations.
A synthesis study of phosphonated PSEBS for high temperature proton exchange membrane fuel cells
Authors: Elumalai Vijayakumar , Annapooranan Raja , Ganapathikrishnan Madhubala , Sangeetha Dharmalingam 
Published: November 2017

ABSTRACTA series of novel phosphonated proton exchange membranes has been prepared using poly(styrene‐ethylene/butylene‐styrene) block copolymer (PSEBS) as base material. Phosphonic acid functionalization of the polymer was performed by a simple two‐step process, via chloromethylation of PSEBS followed by phosphonation utilizing the Michaels–Arbuzov reaction. The successful phosphonation of the polymers were characterized by NMR and Fourier transform infrared. The phosphonated ester form of the membranes were obtained by solvent evaporation method and hydrolyzed to get a proton conducting membrane. The membrane properties such as ion exchange capacity, water uptake and proton conductivity at various temperatures were examined for their suitability to be utilized as a high temperature polymer electrolyte. Additionally, the morphology, thermal, and mechanical properties of the synthesized membranes were investigated, using scanning electron microscope, thermogravimetric analysis, and tensile test, respectively. The effective (anhydrous) proton conductivity was studied with respect to various degrees of functionalization. From the studies, the membranes were found to have a comparatively good conductivity and one of the membranes reached the maximum value of 5.81 mS/cm2 at 140 °C as measured by impedance analyzer. It was found that the synthesized membranes were mechanically durable, chemically, and thermally stable. Hence, the synthesized phosphonated membranes could be a promising candidate for high temperature polymer electrolyte fuel cell applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45954.