bluuebunny/crossref_metadata_2025_split huggingface dataset:
Riverine carbon fluxes to the South China Sea
Authors: Huang T. H. , Chen C. T. A. , Tseng H. C. , Lou J. Y. , Wang S. L. , Yang L. , Kandasamy S. , Gao X. , Wang J. T. , Aldrian E. , Jacinto G. S. , Anshari G. Z. , Sompongchaiyakul P. , Wang B. J. 
Published: May 2017

AbstractThe high precipitation around Southeast Asia results in abundant freshwater outflow, which transports terrestrial dissolved and particulate material to the world's largest marginal sea, namely, the South China Sea (SCS). To estimate the riverine carbon flux to the SCS, carbonate data from 42 rivers were collected. These results, combined with literature data for 13 rivers, indicate that the concentrations of dissolved inorganic carbon (DIC) are positively correlated with the cation exchange capacity and the bulk density, except for the Low Discharge category. The highest DIC concentration and flux are in the Low and Medium Discharge categories. Negative correlations exist between dissolved organic carbon (DOC) concentrations and the base saturation in the Low and High Discharge categories and between DOC and bulk density in the Low and Medium Discharge categories. However, the correlation between the DOC concentration and the organic carbon content in the soil is only significant in the Medium Discharge category. Once the negative exponential relationships between the particulate inorganic carbon (PIC) or the particulate organic carbon (POC) and the total suspended matter are determined, these can be used to estimate the PIC and POC carbon fluxes. Of the annual riverine carbon flux, 83.0 ± 8.1 Tg C, 40.14 ± 6.11 Tg is DIC, 25.03 ± 4.54 Tg is DOC, 1.83 ± 0.35 Tg is PIC, and 16.03 ± 2.87 Tg is POC. The total discharge amounts to 6.2–10.3% of the global riverine discharge for a sea covering only 1% of the world's ocean surface area and for watersheds covering only 2.2% of the global land mass.
Naturally occurring radium (Ra) in home drinking‐water wells in the Sandhills region of South Carolina, USA: Can high concentrations be predicted?
Authors: Schrag Jeffrey M. 
Published: May 2017

AbstractA strong relationship exists between concentrations of several principal constituents of water chemistry and naturally occurring radium in water from home wells in the large Sandhills region of the inner coastal plain of South Carolina, United States, an area of common radium problems (75% (21 of 28 of randomly selected wells in the main study area were above the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL): 5 picocuries per liter for 226Ra plus 228Ra). Ingested radioactive radium is potentially carcinogenic, and water far above the MCL occurs in places. One focus here was to determine if elevated radium concentrations can reliably be predicted using more easily measured characteristics of water chemistry. The initial phase investigated (1) concentrations of radium in well water within a smaller (~10 km radius) test area of known common problems plus (2) the associated water chemistry. This revealed a correlation between elevated radium and raised electrical conductance, total dissolved solids, calcium, nitrate, magnesium, hardness, and lowered pH. All are potentially useful screening tools for the many other rural home wells of this region. Natural groundwater in these highly leached sands is of very low dissolved salt content of all types, and local human influence on geochemistry is thus indicated. Predictive utility was examined by two additional series of wells (1) of higher radium contamination or (2) of elevated calcium concentration, both identified from file data. Higher radium wells were retested for water chemistry and higher calcium wells for radium content. Overall, a similar association between radium and water chemistry was observed.
L band microwave remote sensing and land data assimilation improve the representation of prestorm soil moisture conditions for hydrologic forecasting
Authors: Crow W. T. , Chen F. , Reichle R. H. , Liu Q. 
Published: May 2017

AbstractRecent advances in remote sensing and land data assimilation purport to improve the quality of antecedent soil moisture information available for operational hydrologic forecasting. We objectively validate this claim by calculating the strength of the relationship between storm‐scale runoff ratio (i.e., total streamflow divided by total rainfall accumulation in depth units) and prestorm surface soil moisture estimates from a range of surface soil moisture data products. Results demonstrate that both satellite‐based, L band microwave radiometry and the application of land data assimilation techniques have significantly improved the utility of surface soil moisture data sets for forecasting streamflow response to future rainfall events.
On the historical origins of the CEJ, DP2, and Ddyn current systems and their roles in the predictions of ionospheric responses to geomagnetic storms at equatorial latitudes
Authors: Amory‐Mazaudier C. , Bolaji O. S. , Doumbia V. 
Published: May 2017

AbstractIn this short letter, we recall the differences between the counter electrojet (CEJ), which is a phenomenon observed on the magnetically quiet days and the disturbance dynamo (Ddyn), which can be observed during and after a geomagnetic storm. The CEJ is well known to occur near the geomagnetic dip equator. It can be identified by a reversal in the horizontal component (H) of the geomagnetic field daily regular variations. In contrast to equatorial electrojet (EEJ) that flows eastward in the daytime, the CEJ is considered to flow westward. The magnetic signatures of the reversed solar quiet (Sq) current at the low latitude during magnetic storms are due to the Ddyn. This disturbance (Ddyn) is produced by current systems that are driven by thermospheric storm winds originating from the Joule heating of enhanced high‐latitude currents. The DP2 is the magnetic effect of current systems at high latitudes. These currents are associated with the coupling of magnetosphere and ionosphere through geomagnetic field lines. They are associated to the magnetospheric convection. During intense magnetic storms these high‐latitude currents are enhanced and their magnetic effects can extend toward the low latitudes. This work shows that the study of magnetic perturbations makes it possible to understand the disturbances of the ionospheric electric currents. The use of an efficient treatment of the magnetic signals makes it possible to separate the magnetic effects of the different perturbations prompt penetration of the magnetospheric convection electric field and disturbance dynamo electric field. This was performed in the paper Nava et al. (2016).
Reconciling modeling with observations of radiative absorption of black carbon aerosols
Authors: Chen Bing , Zhu Zhejing , Wang Xinfeng , Andersson August , Chen Jianmin , Zhang Qingzhu , Gustafsson Örjan 
Published: May 2017

AbstractThe physical treatment of internal mixing and aging of black carbon (BC) aerosols that allow for enhanced solar absorption of the BC is an important parameterization in climate models. Many climate models predict a factor of 2–3 lower aerosol absorption optical depth (AAOD) than the atmospheric columnar absorption observed from ground‐based networks such as AERONET, likely because these models do not parameterize properly the BC absorption enhancement (EMAC). Models that are configured with an internal mixing have predicted large variations of EMAC, which are poorly constrained from ambient measurements. We determined the BC EMAC from aerosol coatings with a two‐step solvent experiment to remove both organic and inorganic coatings in ambient fine particulate matter (PM2.5). Observations in a rural North China site showed that the EMAC varied from 1.4 to 3. The EMAC increases simultaneously with SO42−/EC ratios, suggesting the photochemical production of sulfate coatings enhanced BC absorption. A global climate model, parameterized to account for these observational constraints, verifies that sulfates are primary drivers of the BC absorption enhancement in severely polluted area in China. This magnification of the radiative forcing of coated BC is stronger by a factor of ~2 than predicted by the standard parameterization (external mixing) in the climate model and is in better agreement with AERONET observations of AAOD. This result would be useful for testing the representation of solar absorption by BC‐containing particles in the newer generation of climate models.
Wild Bootstrap
Authors: Martin Michael A. 
Published: May 2017

AbstractThe wild bootstrap is a resampling method designed for regression problems with heteroscedastic error structure. The name derives from its use of asingleresidual to estimate the entire conditional distribution of each response through the use of an auxiliary zero‐mean, unit variance random multiplier when resampling. This article describes the development, properties, and software implementation of the wild bootstrap and some of its extensions.
Production of Heterologous Storage Polysaccharides in Potato Plants
Authors: Huang Xing‐Feng , Vincken Jean‐Paul , Visser Richard G.F. , Trindade Luisa M. 
Published: May 2017

AbstractStarch is the most important storage polysaccharide in higher plants. This polysaccharide is used in many industrial applications as it is abundant, renewable and biodegradable and it can be modified into a wide range of products used in food, animal feed, pharmaceuticals and industry. With the understanding of the starch biosynthesis pathway and the isolation of many of the genes involved in this process, the potential for producing novel starches with improved functionality through genetic modification of plants has become more clear. Several different strategies have been used to achieve the rational design of renewable polymers to meet specific requirements. One of these strategies is the regulation of starch biosynthesis and granule assembly in higher plants. A second strategy involves the expression of heterologous genes encoding biosynthetic or modifying enzymes from other organisms to produce novel products with novel functional properties. In this chapter, these recent developments in starch modification in potato plants, such as alteration of starch composition and production of novel storage polysaccharides, are reviewed.
Nitrate Reductase and Nitric Oxide
Authors: Kaiser Werner M. , Planchet Elisabeth , Rümer Stefan 
Published: May 2017

AbstractPlants produce NO either by reduction of nitrite or by oxidation of more reduced N forms. Reductive NO formation from nitrite can be enzymatic via nitrate reductase (NR), mitochondrial electron transport or non‐enzymatic at acidic pH. In any case, NR is the major (if not the only) source for endogenous nitrite in plants. Therefore, NR properties and regulation are summarized here with respect to NO production. Reductive NO formation froml‐arginine or from hydroxylamines is also considered. Problems in quantifying NO production from nitrite and potential roles of NO in plants are discussed in context with nitrate reduction.
The Utilization of Nitrogen by Plants: A Whole Plant Perspective
Authors: Pilbeam David J. 
Published: May 2017

AbstractThe growth of whole plants is dependent on tissue N concentration. Plants that grow in N‐rich environments have higher internal N concentrations and a higher relative growth rate, as described by the N productivity concept. When supply of nitrate N is interrupted, growth is maintained from storage pools of unassimilated nitrate for a limited time. Plants with low N supply show low shoot growth, high root–shoot ratio and decreased leaf growth. N is allocated more to the uppermost leaves, where there is a higher requirement for photosynthetic enzymes and chlorophyll, and mobilized to seeds as the leaves senesce. In actively photosynthesizing leaves, N‐containing primary metabolites are present in relatively constant concentrations, although concentrations of N‐containing secondary metabolites are more variable. The acquisition of nitrate is largely dependent on mass flow across the soil, but acquisition of ammonium depends more on diffusion to the roots. In a crop, uptake over a growing season is regulated by plant demand. This demand is signalled from the shoots to the roots. Some adaptations of roots enable the acquisition of nitrogen before it is acquired by other plants, and species adapted to N‐rich soils have high leaf N concentrations and high specific leaf area, and out‐compete other species for light. Those plants with higher leaf N concentrations seem to be more susceptible to herbivory and attack by micro‐organisms, however.
Abiotic Stress and Metabolomics
Authors: Bowne Jairus , Bacic Antony , Tester Mark , Roessner Ute 
Published: May 2017

AbstractAbiotic stress has major impacts on crop yields worldwide. In the field, multiple stresses often occur simultaneously, and interactions between these stresses will modify the physiological response of plants. We briefly review known tolerance mechanisms and describe approaches that led to their identification, and how new tolerance mechanisms may be identified using ‘omics technologies. We then focus on metabolomics technologies including data analysis, and the results of their application in abiotic stress research. Integration of multiple ‘omics datasets and their interpretation with existing genetic, physiological and morphological data is a challenge that is currently being addressed to enable further exploration and interpretation of metabolomic data. We conclude by discussing new developments in metabolomics, such as single cell measurements of stress responses and tissue‐based mass spectrometry imaging that will offer greater spatial resolution of sub‐cellular distribution of metabolites.
A Role for Metabolomics in Plant Ecology
Authors: van Dam Nicole M. , van der Meijden Eddy 
Published: May 2017

AbstractPlant metabolomic analyses have been mostly applied to analyse metabolomes of crops and model species. However, metabolomic analyses may also be extremely valuable for plant ecologists. Because of the untargeted nature of most metabolomic platforms, the analyses will provide a comprehensive overview of both the primary and secondary plant metabolome. This is especially valuable for chemical ecologists studying plant–herbivore interactions, as both primary and secondary metabolites together determine the performance and preference of herbivores feeding on a plant. A few examples from the recent scientific literature exemplify how metabolomics may yield novel knowledge on the effects of hybridization on plant chemistry, insect resistance and genotype × environment interactions that could not have been so easily obtained with targeted studies alone. Theories and hypotheses regarding optimal defence strategies in plants and invasive plant biology may also benefit from metabolomic analysis. Testable hypotheses built on our current knowledge of plant responses to herbivores and competition may be substantiated and expanded based on metabolomic analyses. Despite some of the limitations that metabolomics analyses may have, the implementation of broad‐spectrum chemical analysis in plant ecology will definitively open up new horizons for plant ecologists and enhance our understanding of the importance of plant chemistry in plant–environment interactions for fundamental and applied research.
Spatially Resolved Plant Metabolomics
Authors: Sumner Lloyd W. , Yang Dong Sik , Bench Bennie J. , Watson Bonnie S. , Li Chao , Jones A. Daniel 
Published: May 2017

Abstract
Primary and secondary metabolism of plants are segregated amidst many differentiated and specialized plant organs, tissues, cells and organelles. The specialized physiology of anatomically distinct components contribute to highly sophisticated, autotrophic systems that are foundational to global energy, ecology, biology and nutrition. An established literature base exists for focused studies of metabolism in specific organs, tissue, cells, and this literature is briefly reviewed here. However, modern metabolic studies are moving towards more global metabolite analyses (i.e. metabolomics and systems biology) with high anatomical, spatial and temporal resolution to better understand the massive complexity of plant systems. Several current examples of such spatially resolved metabolomics experiments are provided here, and the current prospects of metabolite imaging reviewed. Although current metabolomics approaches have been quite informative, they are still constrained by multiple factors. The major challenges that still face plant metabolomics are metabolite annotation, depth‐of‐coverage or comprehensiveness, instrumental sensitivity and dynamic range. These plant metabolomics challenges are discussed in general and relative to temporally and spatially resolved metabolomics.
Data Processing, Metabolomic Databases and Pathway Analysis
Authors: Fiehn Oliver , Kind Tobias , Barupal Dinesh Kumar 
Published: May 2017

AbstractMetabolomics relies on a variety of bioinformatics tools aiming to derive information from data. Data acquisition with chromatography‐coupled mass spectrometry yields high volumes of raw data that need to be processed to achieve de‐noised and meaningful biochemical data that subsequently can be presented for statistics and pathway analysis in a coherent manner. A variety of new tools and algorithms have recently been developed that help in this process. Nevertheless, a surprisingly low number of metabolic signals can be unambiguously identified. If cutting‐edge methods are used, we can confidently interpret signals that can neither be identified by reference standards nor annotated by database matching as ‘novel metabolites’. Such methods may comprise high‐resolution, high‐accurate mass data in conjunction with good data alignment programs that perform peak picking and deconvolution, calculation of elemental formulas, database queries and constraining hit lists by interpreting mass spectral fragmentations and retention‐based metabolomic libraries. In an effort to improve standardizations for metabolomic reports, we propose that not only metabolites must be named but also, for all reported metabolites, identifiers or structure codes (InChI keys) from public (bio)chemical databases need to be detailed. Machine‐readable structures will vastly accelerate our knowledge of the magnitude and importance of the metabolome in various plant species, organs and physiological conditions. We detail how well‐annotated metabolome data can then be used to visualize and interrogate biochemical pathways by matching information to the broad plant databases that currently exist.
2‐Keto‐3‐Deoxy‐l‐Rhamnonate Aldolase (YfaU) as Catalyst in Aldol Additions of Pyruvate to Amino Aldehyde Derivatives
Authors: Hernández Karel , Gómez Ariadna , Joglar Jesús , Bujons Jordi , Parella Teodor , Clapés Pere 
Published: May 2017

Abstract4‐Hydroxy‐2‐keto acid derivatives are versatile building blocks for the synthesis of amino acids, hydroxy carboxylic acids and chiral aldehydes. Pyruvate aldolases are privileged catalysts for a straightforward access to this class of keto acid compounds. In this work, a Class II pyruvate aldolase from Escherichia coli K‐12, 2‐keto‐3‐deoxy‐l‐rhamnonate aldolase (YfaU), was evaluated for the synthesis of amino acid derivatives of proline, pipecolic acid, and pyrrolizidine‐3‐carboxylic acid. The aldol addition of pyruvate to N‐protected amino aldehydes was the key enzymatic aldol addition step followed by catalytic intramolecular reductive amination. The corresponding N‐Cbz‐amino‐4‐hydroxy‐2‐keto acid (Cbz=benzyloxycarbonyl) precursors were obtained in 51–95% isolated yields and enantioselectivity ratios from 26:74 to 95:5, with chiral α‐substituted N‐Cbz‐amino aldehydes. (S)‐N‐Cbz‐amino aldehydes gave aldol adducts with preferentially (R)‐configuration at the newly formed stereocenter, whereas the contrary is true for (R)‐N‐Cbz‐amino aldehydes. Addition reactions to achiral amino aldehydes rendered racemic aldol adducts. Molecular models of the pre‐reaction ternary complexes YfaU‐pyruvate enolate‐acceptor aldehyde were constructed to explain the observed stereochemical outcome of the reactions. Catalytic reductive amination of the aldol adducts yielded 4‐hydroxy‐2‐pipecolic acid, and unprecedented C‐5 substituted 4‐hydroxyproline and pyrrolizidine‐3‐carboxylic acid derivatives.magnified image
Photocontrollable Supramolecular Self‐Assembly of a Porphyrin Derivative that Contains a Polyhedral Oligomeric Silsesquioxane (POSS)
Authors: Zhang Yong , Yue Tao , Cao Hongliang , Gao Yun , Zhang Weian 
Published: May 2017

AbstractIn this study, we have synthesized a new photosensitive organic–inorganic POSS‐containing hybrid porphyrin derivative (H2TPP−Azo−POSS), in which azobenzene was used as a bridge to conjugate the porphyrin and POSS, by using click chemistry. The self‐assembly behavior of H2TPP−Azo−POSS was studied at different concentrations in CHCl3 and in CHCl3/n‐hexane mixed solvent systems. Our results showed that the self‐assembled morphology of H2TPP−Azo−POSS could be tuned by varying the concentration and polarity of the solvent. Spherical micelles and linear nanowires could be obtained in CHCl3, whilst vesicles could be formed in CHCl3/n‐hexane mixtures with low polarities. The supramolecular self‐assembled morphologies of H2TPP−Azo−POSS demonstrated a light‐triggered transition behavior, whilst the size of the assembled aggregates decreased significantly under UV irradiation.
Carbon–Fluorine Reductive Elimination from Nickel(III) Complexes
Authors: Lee Heejun , Börgel Jonas , Ritter Tobias 
Published: May 2017

AbstractWe report a C−F reductive elimination from a characterized first‐row aryl metal fluoride complex. Reductive elimination from the presented nickel(III) complexes is faster than C−F bond formation from any other characterized aryl metal fluoride complex.
A Sustainable Redox‐Flow Battery with an Aluminum‐Based, Deep‐Eutectic‐Solvent Anolyte
Authors: Zhang Changkun , Ding Yu , Zhang Leyuan , Wang Xuelan , Zhao Yu , Zhang Xiaohong , Yu Guihua 
Published: May 2017

AbstractNonaqueous redox‐flow batteries are an emerging energy storage technology for grid storage systems, but the development of anolytes has lagged far behind that of catholytes due to the major limitations of the redox species, which exhibit relatively low solubility and inadequate redox potentials. Herein, an aluminum‐based deep‐eutectic‐solvent is investigated as an anolyte for redox‐flow batteries. The aluminum‐based deep‐eutectic solvent demonstrated a significantly enhanced concentration of circa 3.2 m in the anolyte and a relatively low redox potential of 2.2 V vs. Li+/Li. The electrochemical measurements highlight that a reversible volumetric capacity of 145 Ah L−1 and an energy density of 189 Wh L−1 or 165 Wh kg−1 have been achieved when coupled with a I3−/I− catholyte. The prototype cell has also been extended to the use of a Br2‐based catholyte, exhibiting a higher cell voltage with a theoretical energy density of over 200 Wh L−1. The synergy of highly abundant, dendrite‐free, multi‐electron‐reaction aluminum anodes and environmentally benign deep‐eutectic‐solvent anolytes reveals great potential towards cost‐effective, sustainable redox‐flow batteries.