bluuebunny/crossref_metadata_2025_split huggingface dataset:
Projecting policy‐relevant metrics for high summertime ozone pollution events over the eastern United States due to climate and emission changes during the 21st century
Authors: Rieder Harald E. , Fiore Arlene M. , Horowitz Larry W. , Naik Vaishali 
Published: December 2014

AbstractOver the eastern United States (EUS), nitrogen oxides (NOx) emission controls have led to improved air quality over the past two decades, but concerns have been raised that climate warming may offset some of these gains. Here we analyze the effect of changing emissions and climate, in isolation and combination, on EUS summertime surface ozone (O3) over the recent past and the 21st century in an ensemble of simulations performed with the Geophysical Fluid Dynamics Laboratory CM3 chemistry‐climate model. The simulated summertime EUS O3 is biased high but captures the structure of observed changes in regional O3 distributions following NOx emission reductions. We introduce a statistical bias correction, which allows derivation of policy‐relevant statistics by assuming a stationary mean state bias in the model, but accurate simulation of changes at each quantile of the distribution. We contrast two different 21st century scenarios: (i) representative concentration pathway (RCP) 4.5 and (ii) simulations with well‐mixed greenhouse gases (WMGG) following RCP4.5 but with emissions of air pollutants and precursors held fixed at 2005 levels (RCP4.5_WMGG). We find under RCP4.5 no exceedance of maximum daily 8 hour average ozone above 75 ppb by mid‐21st century, reflecting the U.S. NOx emissions reductions projected in RCP4.5, while more than half of the EUS exceeds this level by the end of the 21st century under RCP4.5_WMGG. Further, we find a simple relationship between the changes in estimated 1 year return levels and regional NOx emission changes, implying that our results can be generalized to estimate changes in the frequency of EUS pollution events under different regional NOx emission scenarios.
Quantitative attribution of major driving forces on soil organic carbon dynamics
Authors: Wu Yiping , Liu Shuguang , Tan Zhengxi 
Published: December 2014

AbstractSoil organic carbon (SOC) storage plays a major role in the global carbon cycle and is affected by many factors including land use/management changes (e.g., biofuel production‐oriented changes). However, the contributions of various factors to SOC changes are not well understood and quantified. This study was designed to investigate the impacts of changing farming practices, initial SOC levels, and biological enhancement of grain production on SOC dynamics and to attribute the relative contributions of major driving forces (CO2 enrichment and farming practices) using a fractional factorial modeling design. The case study at a crop site in Iowa in the United States demonstrated that the traditional corn‐soybean (CS) rotation could still accumulate SOC over this century (from 4.2 to 6.8 kg C/m2) under the current condition; whereas the continuous‐corn (CC) system might have a higher SOC sequestration potential than CS. In either case, however, residue removal could reduce the sink potential substantially. Long‐term simulation results also suggested that the equilibrium SOC level may vary greatly (∼5.7 to ∼11 kg C/m2) depending on cropping systems and management practices, and projected growth enhancement could make the magnitudes higher (∼7.8 to ∼13 kg C/m2). Importantly, the factorial design analysis indicated that residue management had the most significant impact (contributing 49.4%) on SOC changes, followed by CO2 Enrichment (37%), Tillage (6.2%), the combination of CO2 Enrichment‐Residue removal (5.8%), and Fertilization (1.6%). In brief, this study is valuable for understanding the major forces driving SOC dynamics of agroecosystems and informative for decision‐makers when seeking the enhancement of SOC sequestration potential and sustainability of biofuel production, especially in the Corn Belt region of the United States.
and filter design for polytopic continuous‐time Markov jump linear systems with uncertain transition rates
Authors: Morais Cecília F. , Braga Márcio F. , Lacerda Márcio J. , Oliveira Ricardo C. L. F. , Peres Pedro L. D. 
Published: December 2014

SummaryThis paper addresses the problems of
and
full‐order filter design for continuous‐time Markov jump linear systems subject to uncertainties. Different from the available methods in the literature, the main novelty of the proposed approach is the possibility of computing bounds to the
and
norms of the augmented system composed by the uncertain Markov jump linear system plus the robust filter through Lyapunov matrices depending polynomially on the uncertainties affecting independently the matrices of each operation mode and the transition rate matrix. By means of a suitable representation of the uncertainties, the proposed filter design conditions are expressed in terms of linear matrix inequality relaxations associated with searches on scalar parameters. As an additional flexibility, the conditions can be used to synthesize filters with partial, complete, or null Markov mode availability. Numerical experiments illustrate that the proposed approach is more general and can be less conservative than the available methods. Copyright © 2014 John Wiley & Sons, Ltd.
Organocatalytic Enantioselective Sulfur‐Michael Addition of Thioacetic Acid to Arylmethylidenemalonates
Authors: Wang Renchao , Liu Jing , Xu Jiaxi 
Published: December 2014

AbstractAn organocatalytic enantioselective sulfur‐Michael addition of thioacetic acid to arylmethylidenemalonates was developed with high yields and up to 97% enantiomeric excess. Both enantiomers of the products were accessible with two different organocatalysts. The current method provides the first, practical, and convenient preparation of enantiomerically enriched acetylthiomethylmalonate derivatives.magnified image
Utilizing Mor‐DalPhos/Palladium‐Catalyzed Monoarylation in the Multicomponent One‐Pot Synthesis of Indoles
Authors: Rotta‐Loria Nicolas L. , Borzenko Andrey , Alsabeh Pamela G. , Lavery Christopher B. , Stradiotto Mark 
Published: December 2014

AbstractThe application of a Mor‐DalPhos/palladium catalyst system in the one‐pot, multicomponent assembly of substituted indoles from ortho‐chlorohaloarenes, alkyl ketones (including acetone), and primary amines is reported. The described protocols offer improved substrate scope in all three reaction components, under more mild conditions and without the need for an additional drying agent. Also reported are the first examples of such multicomponent reactions where all reactants are combined at the start of the reaction, without the need for inert atmosphere reaction conditions.magnified image
Low mineral density of a weight‐bearing bone among adult women in a high fertility population
Authors: Stieglitz Jonathan , Beheim Bret A. , Trumble Benjamin C. , Madimenos Felicia C. , Kaplan Hillard , Gurven Michael 
Published: December 2014

ABSTRACTEvolutionary theories of aging posit that greater reproductive effort causes somatic decline given a fundamental trade‐off between investing energy in reproduction and repair. Few studies in high fertility human populations support this hypothesis, and problems of phenotypic correlation can obscure the expected trade‐off between reproduction and somatic condition. This cross‐sectional study investigates whether greater reproductive effort is associated with reduced calcaneal bone mineral density (BMD) among female Tsimane forager‐farmers of lowland Bolivia. We also investigate whether female Tsimane BMD values are lower than sex‐ and age‐matched US reference values, despite the fact that Tsimane engage in higher physical activity levels that can increase mechanical loading. To measure calcaneal BMD, quantitative ultrasonography was performed on 130 women (mean ± SD age = 36.6 ± 15.7, range = 15–75) that were recruited regardless of past or current reproductive status. Anthropometric and demographic data were collected during routine medical exams. As predicted, higher parity, short inter‐birth interval, and earlier age at first birth are associated with reduced BMD among Tsimane women after adjusting for potential confounders. Population‐level differences are apparent prior to the onset of reproduction, and age‐related decline in BMD is greater among Tsimane compared with American women. Greater cumulative reproductive burden may lower calcaneal BMD individually and jointly with other lifestyle and heritable factors. Fitness impacts of kin transfers in adulthood may determine the value of investments in bone remodeling, and thus affect selection on age‐profiles of bone mineral loss. Am J Phys Anthropol 156:637–648, 2015. © 2014 Wiley Periodicals, Inc.
Self‐Assembly Structure Formation during the Digestion of Human Breast Milk
Authors: Salentinig Stefan , Phan Stephanie , Hawley Adrian , Boyd Ben J. 
Published: December 2014

AbstractAn infant′s complete diet, human breast milk, is the basis for its survival and development. It contains water‐soluble and poorly water‐soluble bioactive components, metabolic messages, and energy, all of which are made bioavailable during the digestion process in the infant′s gastrointestinal tract. Reported is the first discovery of highly geometrically organized structures formed during the digestion of human breast milk under simulated in vivo conditions using small‐angle X‐ray scattering and cryogenic transmission electron microscopy. Time of digestion, pH, and bile salt concentration were found to have symbiotic effects gradually tuning the oil‐based environment inside the breast milk globules to more water‐like structures with high internal surface area. The structure formation is necessarily linked to its function as carriers for poorly water‐soluble molecules in the digestive tract of the infant.
Particle‐Stabilized Water Droplets that Sprout Millimeter‐Scale Tubes
Authors: Graužinytė Miglė , Forth Joe , Rumble Katherine A. , Clegg Paul S. 
Published: December 2014

AbstractMillimeter‐scale tubes are observed to sprout from water droplets injected into a bath of toluene containing ethanol and silica colloids. This phenomenon requires that first a membrane is formed by the colloids which self‐assemble at the droplet interface, and second, that the ethanol preferentially partitions into the aqueous phase leading to an internal over‐pressure. Tube growth, eruption, and shuffling droplets are subsequently observed, depending on the concentration of ethanol and colloids selected. This work opens many possibilities in the field of biomimetic droplets for fundamental studies of artificial growth at the microscale and for emulsion‐related applications.
Addition of Nitromethane to a Disilene and a Digermene: Comparison to Surface Reactivity and the Facile Formation of 1,3,2‐Dioxazolidines
Authors: Tashkandi Nada Y. , Parsons Frederick , Guo Jiacheng , Baines Kim M. 
Published: December 2014

AbstractThe addition of nitromethane to tetramesityldisilene and tetramesityldigermene leads to the formation of the novel 1,3,2,4,5‐dioxazadisil‐ and digermolidine ring systems, respectively. The 1,3,2,4,5‐dioxazadisilolidine isomerizes to the 1,4,2,3,5‐dioxazadisilolidine ring system, whereas the 1,3,2,4,5‐dioxazadigermolidine undergoes ring opening to the isomeric oxime. The preferential formation of the 1,3,2,4,5‐dioxazadisilolidine, and its rearrangement to a 1,4,2,3,5‐dioxazadisilolidine, provides support for the suggested reaction pathway between nitromethane and the Si(100) 2×1 reconstructed surface.
Excited‐State Charge Separation in the Photochemical Mechanism of the Light‐Driven Enzyme Protochlorophyllide Oxidoreductase
Authors: Heyes Derren J. , Hardman Samantha J. O. , Hedison Tobias M. , Hoeven Robin , Greetham Greg M. , Towrie Michael , Scrutton Nigel S. 
Published: December 2014

AbstractThe unique light‐driven enzyme protochlorophyllide oxidoreductase (POR) is an important model system for understanding how light energy can be harnessed to power enzyme reactions. The ultrafast photochemical processes, essential for capturing the excitation energy to drive the subsequent hydride‐ and proton‐transfer chemistry, have so far proven difficult to detect. We have used a combination of time‐resolved visible and IR spectroscopy, providing complete temporal resolution over the picosecond–microsecond time range, to propose a new mechanism for the photochemistry. Excited‐state interactions between active site residues and a carboxyl group on the Pchlide molecule result in a polarized and highly reactive double bond. This so‐called “reactive” intramolecular charge‐transfer state creates an electron‐deficient site across the double bond to trigger the subsequent nucleophilic attack of NADPH, by the negatively charged hydride from nicotinamide adenine dinucleotide phosphate. This work provides the crucial, missing link between excited‐state processes and chemistry in POR. Moreover, it provides important insight into how light energy can be harnessed to drive enzyme catalysis with implications for the design of light‐activated chemical and biological catalysts.
Magnetic Memory in an Isotopically Enriched and Magnetically Isolated Mononuclear Dysprosium Complex
Authors: Pointillart Fabrice , Bernot Kevin , Golhen Stéphane , Le Guennic Boris , Guizouarn Thierry , Ouahab Lahcène , Cador Olivier 
Published: December 2014

AbstractThe influence of nuclear spin on the magnetic hysteresis of a single‐molecule is evidenced. Isotopically enriched DyIII complexes are synthesized and an isotopic dependence of their magnetic relaxation is observed. This approach is coupled with tuning of the molecular environment through dilution in an amorphous or an isomorphous diamagnetic matrix. The combination of these approaches leads to a dramatic enhancement of the magnetic memory of the molecule. This general recipe can be efficient for rational optimization of single‐molecule magnets (SMMs), and provides an important step for their integration into molecule‐based devices.
Photoliquefiable Ionic Crystals: A Phase Crossover Approach for Photon Energy Storage Materials with Functional Multiplicity
Authors: Ishiba Keita , Morikawa Masa‐aki , Chikara Chie , Yamada Teppei , Iwase Katsunori , Kawakita Mika , Kimizuka Nobuo 
Published: December 2014

AbstractIonic crystals (ICs) of the azobenzene derivatives show photoinduced IC–ionic liquid (IL) phase transition (photoliquefaction) upon UV‐irradiation, and the resulting cis‐azobenzene ILs are reversibly photocrystallized by illumination with visible light. The photoliquefaction of ICs is accompanied by a significant increase in ionic conductivity at ambient temperature. The photoliquefaction also brings the azobenzene ICs further significance as photon energy storage materials. The cis‐IL shows thermally induced crystallization to the trans‐IC phase. This transition is accompanied by exothermic peaks with a total ΔH of 97.1 kJ mol−1, which is almost double the conformational energy stored in cis‐azobenzene chromophores. Thus, the integration of photoresponsive ILs and self‐assembly pushes the limit of solar thermal batteries.
Sulfur‐Doped Graphene Derived from Cycled Lithium–Sulfur Batteries as a Metal‐Free Electrocatalyst for the Oxygen Reduction Reaction
Authors: Ma Zhaoling , Dou Shuo , Shen Anli , Tao Li , Dai Liming , Wang Shuangyin 
Published: December 2014

AbstractHeteroatom‐doped carbon materials have been extensively investigated as metal‐free electrocatalysts to replace commercial Pt/C catalysts in oxygen reduction reactions in fuel cells and Li–air batteries. However, the synthesis of such materials usually involves high temperature or complicated equipment. Graphene‐based sulfur composites have been recently developed to prolong the cycling life of Li–S batteries, one of the most attractive energy‐storage devices. Given the high cost of graphene, there is significant demand to recycle and reuse graphene from Li–S batteries. Herein, we report a green and cost‐effective method to prepare sulfur‐doped graphene, achieved by the continuous charge/discharge cycling of graphene–sulfur composites in Li–S batteries. This material was used as a metal‐free electrocatalyst for the oxygen reduction reaction and shows better electrocatalytic activity than pristine graphene and better methanol tolerance durability than Pt/C.
Hydrogen‐Borrowing and Interrupted‐Hydrogen‐Borrowing Reactions of Ketones and Methanol Catalyzed by Iridium
Authors: Shen Di , Poole Darren L. , Shotton Camilla C. , Kornahrens Anne F. , Healy Mark P. , Donohoe Timothy J. 
Published: December 2014

AbstractReported herein is the use of catalytic [{Ir(cod)Cl}2] to facilitate hydrogen‐borrowing reactions of ketone enolates with methanol at 65 °C. An oxygen atmosphere accelerates the process, and when combined with the use of a bulky monodentate phosphine ligand, interrupts the catalytic cycle by preventing enone reduction. Subsequent addition of pro‐nucleophiles to the reaction mixture allowed a one‐pot methylenation/conjugate addition protocol to be developed, which greatly expands the range of products that can be made by this methodology.
Light‐Directing Omnidirectional Circularly Polarized Reflection from Liquid‐Crystal Droplets
Authors: Fan Jing , Li Yannian , Bisoyi Hari Krishna , Zola Rafael S. , Yang Deng‐ke , Bunning Timothy J. , Weitz David A. , Li Quan 
Published: December 2014

AbstractConstructing and tuning self‐organized three‐dimensional (3D) superstructures with tailored functionality is crucial in the nanofabrication of smart molecular devices. Herein we fabricate a self‐organized, phototunable 3D photonic superstructure from monodisperse droplets of one‐dimensional cholesteric liquid crystal (CLC) containing a photosensitive chiral molecular switch with high helical twisting power. The droplets are obtained by a glass capillary microfluidic technique by dispersing into PVA solution that facilitates planar anchoring of the liquid‐crystal molecules at the droplet surface, as confirmed by the observation of normal incidence selective circular polarized reflection in all directions from the core of individual droplet. Photoirradiation of the droplets furnishes dynamic reflection colors without thermal relaxation, whose wavelength can be tuned reversibly by variation of the irradiation time. The results provided clear evidence on the phototunable reflection in all directions.
The Profound Effect of the Ring Size in the Electrocyclic Opening of Cyclobutene‐Fused Bicyclic Systems
Authors: Ralph Michael J. , Harrowven David C. , Gaulier Steven , Ng Sean , Booker‐Milburn Kevin I. 
Published: December 2014

AbstractFused cyclobutenes, prepared by the photocycloaddition of propargyl alcohols to cyclic anhydride chromophores, undergo facile thermochemical ring opening to fused γ‐lactones. The size of the fused ring profoundly influences the temperature that is required to facilitate the ring opening (from 50 °C to 180 °C) and the nature of the product that is formed. Our studies provide new insights into the mechanistic course of these reactions and have been extended to facilitate the preparation of lactams fused to medium‐sized rings.
PyBidine–Cu(OTf)2‐Catalyzed Asymmetric [3+2] Cycloaddition with Imino Esters: Harmony of Cu–Lewis Acid and Imidazolidine‐NH Hydrogen Bonding in Concerto Catalysis
Authors: Arai Takayoshi , Ogawa Hiroki , Awata Atsuko , Sato Makoto , Watabe Megumi , Yamanaka Masahiro 
Published: December 2014

AbstractA bis(imidazolidine)pyridine (PyBidine)–Cu(OTf)2 complex catalyzing the endo‐selective [3+2] cycloaddition of nitroalkenes with imino esters was applied to the reaction of methyleneindolinones with imino esters to afford spiro[pyrrolidin‐3,3′‐oxindole]s in up to 98 % ee. X‐ray crystallographic analysis of the PyBidine–Cu(OTf)2 complex and DFT calculations suggested that an intermediate Cu enolate of the imino ester reacts with nitroalkenes or methyleneindolinones, which are activated by NH‐hydrogen bonding with the PyBidine–Cu(OTf)2 catalyst.
Fouling control through the hydrophilic surface modification of poly(vinylidene fluoride) membranes
Authors: Jang Hanna , Song Du‐Hyun , Kim In‐Chul , Kwon Young‐Nam 
Published: December 2014

ABSTRACTA hydrophilic fouling‐resistant poly(vinyl alcohol) (PVA) based polymer was synthesized by the etherification of PVA with monochloroacetic acid under alkaline conditions, and the polymer, PVA–OCH2COONa, was subsequently applied to modify a poly(vinylidene fluoride) (PVDF) membrane to both enhance the hydrophilicity and provide fouling resistance. The successful etherification was confirmed by 13C‐NMR and attenuated total reflectance–Fourier transform infrared spectroscopy, whereas the synthesized polymer was shown by differential scanning calorimetry analysis to have an improved thermal stability over PVA. The physicochemical properties of the surfaces of the modified PVDF membranes were investigated with various analytical tools, including field emission scanning electron microscopy, atomic force microscopy, and contact angle analysis. Fouling tests with bovine serum albumin showed the PVA–OCH2COONa modified PVDF membrane to have both a higher pure water flux and a retarded decline in flux over the filtration period compared with the PVA‐coated PVDF membrane. This study demonstrated that the modification of PVDF membranes with PVA–OCH2COONa could be an efficient method for enhancing their fouling resistance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41712.
Influence of the nanofiber dimensions on the properties of nanocellulose/poly(vinyl alcohol) aerogels
Authors: Mueller Silvana , Sapkota Janak , Nicharat Apiradee , Zimmermann Tanja , Tingaut Philippe , Weder Christoph , Foster E. Johan 
Published: December 2014

ABSTRACTThe investigation of aerogels made from cellulose nanofibers and poly(vinyl alcohol) (PVOH) as a polymeric binder is reported. Aerogels based on different nanocellulose types were studied to investigate the influence of the nanocellulose dimensions and their rigidity on the morphology and mechanical properties of the resulting aerogels. Thus, cellulose nanocrystals (CNCs) with low (10), medium (25), and high (80) aspect ratios, isolated from cotton, banana plants, and tunicates, respectively, microfibrillated cellulose (MFC) and microcrystalline cellulose (MCC) were dispersed in aqueous PVOH solutions and aerogels were prepared by freeze‐drying. In addition to the cellulose type, the PVOH‐ and the CNC‐concentration as well as the freeze‐drying conditions were varied, and the materials were optionally cross‐linked by an annealing step or the use of a chemical cross‐linker. The data reveal that at low PVOH content, rigid, high‐aspect ratio CNCs isolated from tunicates afford aerogels that show the least amount of shrinking upon freeze‐drying and display the best mechanical properties. However, with increasing concentration of PVOH or upon introduction of a chemical cross‐linker the differences between materials made from different nanocellulose types decrease. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41740.