bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased influence of nitrogen limitation on CO2 emissions from future land use and land use change
Authors: Meiyappan Prasanth , Jain Atul K. , House Joanna I. 
Published: August 2015

AbstractIn the latest projections of future greenhouse gas emissions for the Intergovernmental Panel on Climate Change (IPCC), few Earth System Models included the effect of nitrogen limitation, a key process limiting forest regrowth. Few included forest management (wood harvest). We estimate the impacts of nitrogen limitation on the CO2 emissions from land use and land use change (LULUC), including wood harvest, for the period 1900–2100. We use a land surface model that includes a fully coupled carbon and nitrogen cycle and accounts for forest regrowth processes following agricultural abandonment and wood harvest. Future projections are based on the four Representation Concentration Pathways used in the IPCC Fifth Assessment Report, and we account for uncertainty in future climate for each scenario based on ensembles of climate model outputs. Results show that excluding nitrogen limitation will underestimate global LULUC emissions by 34–52 PgC (20–30%) during the 20th century (range across three different historical LULUC reconstructions) and by 128–187 PgC (90–150%) during the 21st century (range across the four IPCC scenarios). The full range for estimated LULUC emissions during the 21st century including climate model uncertainty is 91 to 227 PgC (with nitrogen limitation included). The underestimation increases with time because (1) projected annual wood harvest rates from forests summed over the 21st century are 380–1080% higher compared to those of the 20th century, resulting in more regrowing secondary forests; (2) nitrogen limitation reduces the CO2 fertilization effect on net primary production of regrowing secondary forests following wood harvest and agricultural abandonment; and (3) nitrogen limitation effect is aggravated by the gradual loss of soil nitrogen from LULUC disturbance. Our study implies that (1) nitrogen limitation of CO2 uptake is substantial and sensitive to nitrogen inputs; (2) if LULUC emissions are larger than previously estimated in studies without nitrogen limitation, then meeting the same climate mitigation target would require an equivalent additional reduction of fossil fuel emissions; (3) the effectiveness of land‐based mitigation strategies will critically depend on the interactions between nutrient limitations and secondary forests resulting from LULUC; and (4) it is important for terrestrial biosphere models to consider nitrogen constraint in estimates of the strength of future land carbon uptake.
Sediment dynamics in the lowerMekongRiver: Transition from tidal river to estuary
Authors: Nowacki Daniel J. , Ogston Andrea S. , Nittrouer Charles A. , Fricke Aaron T. , Van Pham Dang Tri 
Published: August 2015

AbstractA better understanding of flow and sediment dynamics in the lowermost portions of large‐tropical rivers is essential to constraining estimates of worldwide sediment delivery to the ocean. Flow velocity, salinity, and suspended‐sediment concentration were measured for 25 h at three cross sections in the tidal Song Hau distributary of the Mekong River, Vietnam. Two campaigns took place during comparatively high‐seasonal and low‐seasonal discharge, and estuarine conditions varied dramatically between them. The system transitioned from a tidal river with ephemeral presence of a salt wedge during high flow to a partially mixed estuary during low flow. The changing freshwater input, sediment sources, and estuarine characteristics resulted in seaward sediment export during high flow and landward import during low flow. The Dinh An channel of the Song Hau distributary exported sediment to the coast at a rate of about 1 t s−1during high flow and imported sediment in a spatially varying manner at approximately 0.3 t s−1during low flow. Scaling these values results in a yearly Mekong sediment discharge estimate about 65% smaller than a generally accepted estimate of 110 Mt yr−1, although the limited temporal and spatial nature of this study implies a relatively high degree of uncertainty for the new estimate. Fluvial advection of sediment was primarily responsible for the high‐flow sediment export. Exchange‐flow and tidal processes, including local resuspension, were principally responsible for the low‐flow import. The resulting bed‐sediment grain size was coarser and more variable during high flow and finer during low, and the residual flow patterns support the maintenance of mid‐channel islands.
Chemical imaging of ambient aerosol particles: Observational constraints on mixing state parameterization
Authors: O'Brien Rachel E. , Wang Bingbing , Laskin Alexander , Riemer Nicole , West Matthew , Zhang Qi , Sun Yele , Yu Xiao‐Ying , Alpert Peter , Knopf Daniel A. , Gilles Mary K. , Moffet Ryan C. 
Published: August 2015

AbstractA new parameterization for quantifying the mixing state of aerosol populations has been applied for the first time to samples of ambient particles analyzed using spectro‐microscopy techniques. Scanning transmission X‐ray microscopy/near edge X‐ray absorption fine structure (STXM/NEXAFS) and computer‐controlled scanning electron microscopy/energy dispersive X‐ray spectroscopy (CCSEM/EDX) were used to probe the composition of the organic and inorganic fraction of individual particles collected on 27 and 28 June during the 2010 Carbonaceous Aerosols and Radiative Effects study in the Central Valley, California. The first field site, T0, was located in downtown Sacramento, while T1 was located near the Sierra Nevada Mountains. Mass estimates of the aerosol particle components were used to calculate mixing state metrics, such as the particle‐specific diversity, bulk population diversity, and mixing state index, for each sample. The STXM data showed evidence of changes in the mixing state associated with a buildup of organic matter confirmed by collocated measurements, and the largest impact on the mixing state was due to an increase in soot dominant particles during this buildup. The mixing state from STXM was similar between T0 and T1, indicating that the increased organic fraction at T1 had a small effect on the mixing state of the population. The CCSEM/EDX analysis showed the presence of two types of particle populations: the first was dominated by aged sea‐salt particles and had a higher mixing state index (indicating a more homogeneous population); the second was dominated by carbonaceous particles and had a lower mixing state index.
Evaluation of tropical channel refinement using MPAS‐A aquaplanet simulations
Authors: Martini Matus N. , Gustafson William I. , O'Brien Travis A. , Ma Po‐Lun 
Published: August 2015

AbstractClimate models with variable‐resolution grids offer a computationally less expensive way to provide more detailed information and increased accuracy by resolving processes that cannot be adequately represented by a coarser grid. This study uses the Model for Prediction Across Scales‐Atmosphere (MPAS‐A), consisting of a nonhydrostatic dynamical core and a subset of Weather Research and Forecasting (WRF) model physics, to investigate the potential benefits of using tropical channel refinement. The simulations are performed with an idealized aquaplanet configuration using 30 and 240 km global grid spacing, and two variable‐resolution grids spanning the same grid spacing range; one with a narrow (20°S–20°N) and one with a wide (30°S–30°N) tropical channel refinement. Increasing resolution in the tropics impacts both the tropical and extratropical circulation. Compared to the 30 km global grid, both refined channel simulations exhibit slightly stronger updrafts inside the Hadley cell resulting in more resolved precipitation. Using a wider tropical refinement leads to a closer correspondence with the global high‐resolution grid. While different grid spacings produce similar cloud size distributions that are consistent with observations, the dependence of precipitation rate on cloud size varies among simulations. The refined channel simulations show improved tropical and extratropical precipitation relative to the global coarse simulation. All simulations show a single precipitation peak centered on the equator. Although the results show that tropical refinement is an effective method for avoiding artifacts due to grid resolution sensitivities seen in earlier studies that only refined a portion of the tropics, some biases remain well inside of the refinement region.
Adaptive filters cascade applied to a frequency identification improvement problem
Authors: Aranovskiy Stanislav V. , Bobtsov Alexey A. , Pyrkin Anton A. , Gritcenko Polina A. 
Published: August 2015

SummaryProblem of frequency identification performance improvement for a single‐tone sinusoidal signal is solved via construction of an adaptive filters cascade. The cascade consists of adaptive band‐pass filters tuned by estimates of the frequency provided by a given identification algorithm. Stability of the cascade is studied and boundedness of trajectories is proven with Lyapunov analysis under certain assumption on identification algorithm. Numerical simulations are given illustrating improved identification performance for different identification algorithms. Copyright © 2015 John Wiley & Sons, Ltd.
Site‐Directed, On‐Surface Assembly of DNA Nanostructures
Authors: Meyer Rebecca , Saccà Barbara , Niemeyer Christof M. 
Published: August 2015

AbstractTwo‐dimensional DNA lattices have been assembled from DNA double‐crossover (DX) motifs on DNA‐encoded surfaces in a site‐specific manner. The lattices contained two types of single‐stranded protruding arms pointing into opposite directions of the plane. One type of these protruding arms served to anchor the DNA lattice on the solid support through specific hybridization with surface‐bound, complementary capture oligomers. The other type of arms allowed for further attachment of DNA‐tethered probe molecules on the opposite side of the lattices exposed to the solution. Site‐specific lattice assembly and attachment of fluorophore‐labeled oligonucleotides and DNA–protein conjugates was demonstrated using DNA microarrays on flat, transparent mica substrates. Owing to their programmable orientation and addressability over a broad dynamic range from the nanometer to the millimeter length scale, such supramolecular architecture might be used for presenting biomolecules on surfaces, for instance, in biosensor applications.
Large‐Area, Free‐Standing, Two‐Dimensional Supramolecular Polymer Single‐Layer Sheets for Highly Efficient Electrocatalytic Hydrogen Evolution
Authors: Dong Renhao , Pfeffermann Martin , Liang Haiwei , Zheng Zhikun , Zhu Xiang , Zhang Jian , Feng Xinliang 
Published: August 2015

AbstractThe rational construction of covalent or noncovalent organic two‐dimensional nanosheets is a fascinating target because of their promising applications in electronics, membrane technology, catalysis, sensing, and energy technologies. Herein, a large‐area (square millimeters) and free‐standing 2D supramolecular polymer (2DSP) single‐layer sheet (0.7–0.9 nm in thickness), comprising triphenylene‐fused nickel bis(dithiolene) complexes has been readily prepared by using the Langmuir–Blodgett method. Such 2DSPs exhibit excellent electrocatalytic activities for hydrogen generation from water with a Tafel slope of 80.5 mV decade−1 and an overpotential of 333 mV at 10 mA cm−2, which are superior to that of recently reported carbon nanotube supported molecular catalysts and heteroatom‐doped graphene catalysts. This work is promising for the development of novel free‐standing organic 2D materials for energy technologies.
Multidimensional Electronic Spectroscopy of Photochemical Reactions
Authors: Nuernberger Patrick , Ruetzel Stefan , Brixner Tobias 
Published: August 2015

AbstractCoherent multidimensional electronic spectroscopy can be employed to unravel various channels in molecular chemical reactions. This approach is thus not limited to analysis of energy transfer or charge transfer (i.e. processes from photophysics), but can also be employed in situations where the investigated system undergoes permanent structural changes (i.e. in photochemistry). Photochemical model reactions are discussed by using the example of merocyanine/spiropyran‐based molecular switches, which show a rich variety of reaction channels, in particular ring opening and ring closing, cis–trans isomerization, coherent vibrational wave‐packet motion, radical ion formation, and population relaxation. Using pump‐probe, pump‐repump‐probe, coherent two‐dimensional and three‐dimensional, triggered‐exchange 2D, and quantum‐control spectroscopy, we gain intuitive pictures on which product emerges from which reactant and which reactive molecular modes are associated.
Ortho‐Stabilized 18F‐Azido Click Agents and their Application in PET Imaging with Single‐Stranded DNA Aptamers
Authors: Wang Lu , Jacobson Orit , Avdic Din , Rotstein Benjamin H. , Weiss Ido D. , Collier Lee , Chen Xiaoyuan , Vasdev Neil , Liang Steven H. 
Published: August 2015

AbstractAzido 18F‐arenes are important and versatile building blocks for the radiolabeling of biomolecules via Huisgen cycloaddition (“click chemistry”) for positron emission tomography (PET). However, routine access to such clickable agents is challenged by inefficient and/or poorly defined multistep radiochemical approaches. A high‐yielding direct radiofluorination for azido 18F‐arenes was achieved through the development of an ortho‐oxygen‐stabilized iodonium derivative (OID). This OID strategy addresses an unmet need for a reliable azido 18F‐arene clickable agent for bioconjugation reactions. A ssDNA aptamer was radiolabeled with this agent and visualized in a xenograft mouse model of human colon cancer by PET, which demonstrates that this OID approach is a convenient and highly efficient way of labeling and tracking biomolecules.
Mechanism of Nickel(II)‐Catalyzed Oxidative C(sp2)−H/C(sp3)−H Coupling of Benzamides and Toluene Derivatives
Authors: Xu Zheng‐Yang , Jiang Yuan‐Ye , Yu Hai‐Zhu , Fu Yao 
Published: August 2015

AbstractThe Ni‐catalyzed C(sp2)−H/C(sp3)−H coupling of benzamides with toluene derivatives was recently successfully achieved with mild oxidant iC3F7I. Herein, we employ density functional theory (DFT) methods to resolve the mechanistic controversies. Two previously proposed mechanisms are excluded, and our proposed mechanism involving iodine‐atom transfer (IAT) between iC3F7I and the NiII intermediate was found to be more feasible. With this mechanism, the presence of a carbon radical is consistent with the experimental observation that (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) completely quenches the reaction. Meanwhile, the hydrogen‐atom abstraction of toluene is irreversible and the activation of the C(sp2)−H bond of benzamides is reversible. Both of these conclusions are in good agreement with Chatani's deuterium‐labeling experiments.
Transient neonatal diabetes due to a missense mutation (E227K) in the gene encoding the ATP‐sensitive potassium channel (KCNJ11)
Authors: Martins Luísa , Lourenço Rita , Maia Ana Lúcia , Maciel Paula , Monteiro Maria Isabel , Pacheco Lucinda , Anselmo João , César Rui , Gomes Maria Fernanda 
Published: August 2015

Key Clinical MessageNeonatal diabetes is a monogenic form of diabetes. Herein, we report on a newborn presenting diabetic ketoacidosis at 17 days of life . A KCNJ11 mutation was identified. In such cases, insulin can be replaced by sulfonylurea with a successful metabolic control, as an example of how molecular diagnosis may influence the clinical management of the disorder.
Are de novo rea(21;21) chromosomes really de novo?
Authors: Hervé Bérénice , Quibel Thibaud , Taieb Stéphane , Ruiz Mireille , Molina‐Gomes Denise , Vialard François 
Published: August 2015

Key Clinical MessageWe report a rare case of recurrent trisomy 21 caused by an isochromosome 21q and what is very likely to be maternal germ‐line cell mosaicism. Over 90% of cases of rob(21;21) reported in the literature are due to an isochromosome 21q, with a risk of recurrence of more than 10%.
Early‐onset hypoparathyroidism and chronic keratitis revealing APECED
Authors: Mezgueldi Ellia , Bertholet‐Thomas Aurélia , Milazzo Solange , Morris Michael , Bacchetta Justine , Fabien Nicole , Cochat Pierre , Weetman Anthony P. , Kemp Elizabeth Helen , Belot Alexandre 
Published: August 2015

Key Clinical MessageEarly diagnosis of potentially life‐threatening autoimmune polyendocrinopathy‐candidiasis‐ectodermal dystrophy (APECED) is crucial, but is often delayed due to the clinical heterogeneity of the disorder. Even in the absence of the classic disease triad of chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenocortical insufficiency, a diagnosis of APECED should be considered in children who have hypoparathyroidism and chronic keratitis, with a past medical history showing a mild and transient Candida infection.
Kinetic Model for Invertase‐Induced Sucrose Hydrolysis: Initial Time Lag
Authors: Keramat Ali , Kargari Ali , Sohrabi† Morteza , Mirshekar Hamed , Sanaeepur Hamidreza 
Published: August 2015

AbstractThe kinetics of sucrose hydrolysis by invertase was studied in order to find a comprehensive model for the reaction pathway and mechanism. First, three common models of Michaelis‐Menten (MM), substrate inhibition (S2), and substrate clusters' inhibition (S3(I)) were investigated. The third model was found to better predict the initial sucrose concentration. Then, the S3(I) model was modified to cover the remaining pathway (S3(II)). Finally, a new comprehensive model (S3(III)) was evaluated, which in addition to what is considered in the two previously mentioned models (S3(I) and S3(II)) also involved the initial time lag. The model predictions showed an excellent agreement with the experimental data. The mean absolute error for the MM model is significantly reduced for the S3(III) model.
Enhanced Silica Removal by Polyamine‐ and Polyacrylamide‐Polyaluminum Hybrid Coagulants
Authors: Miranda Ruben , Latour Isabel , Hörsken Arne , Jarabo Rocío , Blanco Angeles 
Published: August 2015

AbstractSilica removal is the main bottleneck for a high reuse of deinking paper mill effluents due to silica scaling on the reverse‐osmosis units generally used. The efficiency of inorganic‐organic hybrid coagulants formed by the combination of polyaluminum nitrate sulfate (PANS) with different dosages of cationic polyacrylamide (PAM) or polyamines (PA) on silica removal is analyzed. These hybrids significantly increased the silica and chemical oxygen demand (COD) removal at all pH values studied, with PA modification being the most efficient. While conventional aluminum coagulants allow high silica removal, only at both high pH and dosages the PA derivatives achieve high silica and soluble COD removal without pH adjustment. PAM hybrids only slightly improved the efficiency of PANS at the highest active contents.
Retention of Biopolymers by Ultrafiltration Membranes
Authors: Arkhangelsky Elizabeth , Levitsky Inna , Gitis Vitaly 
Published: August 2015

AbstractSeparation of biopolymers is one of increasingly important applications of ultrafiltration (UF) membranes. The efficiency of separation is often evaluated through pilot experiments and seldom predicted. Available predictions focus on correlations between UF pore width and biopolymer hydrodynamic diameter, while overlooking key operational parameters including transmembrane pressure (TMP). The role of TMP in the retention of biopolymers is revealed, i.e., magnification of TMP leads to decreased retention of the particulates. No full retention of the biopolymers without a rigid outer shell has been observed. Pressure‐induced stretching of flexible biopolymers and expansion of membrane pores are the possible reasons of deteriorating selectivity. A division into flexible and rigid biopolymers provides a better prediction of membrane selectivity.
Electrochemistry of Nitrated N‐Confused Free‐Base Tetraaryl‐Porphyrins in Nonaqueous Media
Authors: Ye Lina , Ou Zhongping , Fang Yuanyuan , Xue Songlin , Chen Xueyan , Lu Guifen , Jiang Xiaoqin , Kadish Karl M. 
Published: August 2015

AbstractFour nitrated N‐confused free‐base tetraarylporphyrins were synthesized and characterized by electrochemistry and spectroelectrochemistry in nonaqueous media. The examined compounds are represented as NO2(Ar)4NcpH2, where NO2(Ar)4Ncp is the dianion of a tetraaryl N‐confused porphyrin with an inner carbon bound NO2 group and Ar is a p‐CH3OPh, p‐CH3Ph, Ph or p‐ClPh substituent on each meso‐position of the macrocycle. UV/Vis spectra and NMR spectroscopy data indicate that the same form of the porphyrin exists in CH2Cl2 and DMF which is unlike the case of non‐NO2 N‐confused porphyrins. The Soret band of NO2(Ar)4NcpH2 exhibits a 30–36 nm red‐shift in CH2Cl2 and DMF as compared to the spectrum of the non‐NO2 N‐confused porphyrins. The first two reductions and first oxidation of NO2(Ar)4NcpH2 are reversible in CH2Cl2 containing 0.1 M TBAP. The measured HOMO–LUMO gap averages 1.65 V in CH2Cl2 and 1.53 V in DMF, with both values being similar to those of the non‐NO2 substituted compounds. The nitro group on the inverted pyrrole is itself not reduced within the negative potential limit of CH2Cl2 or DMF, but its presence significantly affects both the UV/Vis spectra and redox potentials.
New Stable and Persistent Acyclic Diaminocarbenes
Authors: Schulz Tim , Weismann Daniel , Wallbaum Lars , Guthardt Robin , Thie Charlotte , Leibold Michael , Bruhn Clemens , Siemeling Ulrich 
Published: August 2015

AbstractThe portfolio of acyclic diaminocarbenes (ADACs) has been substantially expanded, owing to the synthesis of eleven new formamidinium salts, mostly of the type [(iPr2N)CH(NRR′)][PF6], for use as immediate carbene precursors. The corresponding ADACs (iPr2N)C(NRR′) were sufficiently stable for isolation in the case of NRR′=2‐methylpiperidino (13), 3‐methylpiperidino (14), 4‐methylpiperidino (15), morpholino (17) and NiPrPh (20), but had to be trapped in situ in the case of NRR′=2,2,6,6‐tetramethylpiperidino (12) and NiPrMe (19). The tetraaryl‐substituted ADACs (Ph2N)2C (22) and (Ph2N)C[N(C6F5)2] (24) also could only be generated and trapped in situ. Trapping with elemental selenium was particularly efficient, affording the corresponding selenourea derivative in all cases, whereas trapping with [{Rh(μ‐Cl)(cod)}2] did not work for 12 and 24. The 77Se NMR chemical shifts, δ(77Se), of the selenourea compounds derived from the new ADACs lie in the range 450–760 ppm, which indicates a much higher electrophilicity and π‐accepting capability of ADACs in comparison with NHCs, which typically exhibit δ(77Se)<200 ppm. The extreme low‐field shift of 758 ppm observed for 12Se can be rationalised by the results of DFT calculations, which revealed that ADAC 12 has a minimum energy conformation with the 2,2,6,6‐tetramethylpiperidino unit perpendicular to the N2C plane, which suppresses the π donation of this amino group and causes an unusually low LUMO energy and high electrophilicity.
Pentacoordinated Carboxylate π‐Allyl Nickel Complexes as Key Intermediates for the Ni‐Catalyzed Direct Amination of Allylic Alcohols
Authors: Kita Yusuke , Sakaguchi Hironobu , Hoshimoto Yoichi , Nakauchi Daisuke , Nakahara Yasuhito , Carpentier Jean‐François , Ogoshi Sensuke , Mashima Kazushi 
Published: August 2015

AbstractDirect amination of allylic alcohols with primary and secondary amines catalyzed by a system made of [Ni(1,5‐cyclooctadiene)2] and 1,1′‐bis(diphenylphosphino)ferrocene was effectively enhanced by adding nBu4NOAc and molecular sieves, affording the corresponding allyl amines in high yield with high monoallylation selectivity for primary amines and high regioselectivity for monosubstituted allylic alcohols. Such remarkable additive effects of nBu4NOAc were elucidated by isolating and characterizing some nickel complexes, manifesting the key role of a charge neutral pentacoordinated η3‐allyl acetate complex in the present system, in contrast to usual cationic tetracoordinated complexes earlier reported in allylic substitution reactions.