bluuebunny/crossref_metadata_2025_split huggingface dataset:
Essential Oil Composition and Volatile Profile of Seven Helichrysum Species Grown in Italy
Authors: Giovanelli Silvia , De Leo Marinella , Cervelli Claudio , Ruffoni Barbara , Ciccarelli Daniela , Pistelli Luisa 
Published: March 2018

Helichrysum genus consists of about 600 species widespread throughout the world, especially in South Africa and in the Mediterranean area. In this study the aroma profile (HS‐SPME) and the EO compositions of seven Helichrysum species (H. cymosum, H. odoratissimum, H. petiolare, H. fontanesii, H. saxatile, H. sanguineum, and H. tenax) were evaluated. All the plants were grown in Italy under the same growth conditions. The volatile constituents, particularly monoterpenes, depended by the plant's genotype and ecological adaptation. This study represents the first headspace evaluation on the selected plants and the results evidenced that monoterpenes represented the main class of constituents in five of the seven species analysed (from 59.2% to 95.0%). The higher content in sesquiterpene hydrocarbons was observed in the Mediterranean species of H. sanguineum (68.0%). Only H. saxatile showed relative similar abundance of monoterpenes and sesquiterpene hydrocarbons. The essential oil composition of the majority of examined species are characterised by high percentage of sesquiterpenes (especially β‐caryophyllene and δ‐cadinene) ranging from 51.3% to 92.0%, except for H. cymosum, H. tenax, and H. sanguineum leaves where monoterpenes predominated (from 51.7% to 74.7%).
Exploration of Strategies for Mechanism‐Based Inhibitor Design for Family GH99 endo‐α‐1,2‐Mannanases
Authors: Fernandes Pearl Z. , Petricevic Marija , Sobala Lukasz , Davies Gideon J. , Williams Spencer J. 
Published: March 2018

Abstractendo‐α‐1,2‐Mannosidases and ‐mannanases, members of glycoside hydrolase family 99 (GH99), cleave α‐Glc/Man‐1,3‐α‐Man‐OR structures within mammalian N‐linked glycans and fungal α‐mannan, respectively. They are proposed to act through a two‐step mechanism involving a 1,2‐anhydrosugar “epoxide” intermediate incorporating two conserved catalytic carboxylates. In the first step, one carboxylate acts as a general base to deprotonate the 2‐hydroxy group adjacent to the fissile glycosidic bond, and the other provides general acid assistance to the departure of the aglycon. We report herein the synthesis of two inhibitors designed to interact with either the general base (α‐mannosyl‐1,3‐(2‐aminodeoxymannojirimycin), Man2NH2DMJ) or the general acid (α‐mannosyl‐1,3‐mannoimidazole, ManManIm). Modest affinities were observed for an endo‐α‐1,2‐mannanase from Bacteroides thetaiotaomicron. Structural studies revealed that Man2NH2DMJ binds like other iminosugar inhibitors, which suggests that the poor inhibition shown by this compound is not a result of a failure to achieve the expected interaction with the general base, but rather the reduction in basicity of the endocyclic nitrogen caused by introduction of a vicinal, protonated amine at C2. ManManIm binds with the imidazole headgroup distorted downwards, a result of an unfavourable interaction with a conserved active site tyrosine. This study has identified important limitations associated with mechanism‐inspired inhibitor design for GH99 enzymes.
ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
Authors: Moore Peter W. , Read Christopher D. G. , Bernhardt Paul V. , Williams Craig M. 
Published: March 2018

AbstractThe Ley–Griffith tetra‐n‐propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
A General Catalytic Method for Highly Cost‐ and Atom‐Efficient Nucleophilic Substitutions
Authors: Huy Peter H. , Filbrich Isabel 
Published: March 2018

AbstractA general formamide‐catalyzed protocol for the efficient transformation of alcohols into alkyl chlorides, which is promoted by substoichiometric amounts (down to 34 mol %) of inexpensive trichlorotriazine (TCT), is introduced. This is the first example of a TCT‐mediated dihydroxychlorination of an OH‐containing substrate (e.g., alcohols and carboxylic acids) in which all three chlorine atoms of TCT are transferred to the starting material. The consequently enhanced atom economy facilitates a significantly improved waste balance (E‐factors down to 4), cost efficiency, and scalability (>50 g). Furthermore, the current procedure is distinguished by high levels of functional‐group compatibility and stereoselectivity, as only weakly acidic cyanuric acid is released as exclusive byproduct. Finally, a one‐pot protocol for the preparation of amines, azides, ethers, and sulfides enabled the synthesis of the drug rivastigmine with twofold SN2 inversion, which demonstrates the high practical value of the presented method.
Salicylic Acid‐Based Polymeric Contrast Agents for Molecular Magnetic Resonance Imaging of Prostate Cancer
Authors: Banerjee Sangeeta Ray , Song Xiaolei , Yang Xing , Minn Il , Lisok Ala , Chen Yanrong , Bui Albert , Chatterjee Samit , Chen Jian , van Zijl Peter C. M. , McMahon Michael T. , Pomper Martin G. 
Published: March 2018

AbstractChemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is an innovative molecular imaging technique in which contrast agents are labeled by saturating their exchangeable proton spins by radio‐frequency irradiation. Salicylic acid and its analogues are a promising class of highly sensitive, diamagnetic CEST agents. Herein, polymeric agents grafted with salicylic acid moieties and a known high‐affinity ligand targeting prostate‐specific membrane antigen in approximately 10:1 molar ratio were synthesized to provide sufficient MRI sensitivity and receptor specificity. The proton‐exchange properties of the contrast agent in solution and in an experimental murine model are reported to demonstrate the feasibility of receptor‐targeted CEST MRI of prostate cancer. Furthermore, the CEST imaging data were validated with an 111In‐labeled analogue of the agent by in vivo single photon emission computed tomographic imaging and tissue biodistribution studies.
Internal Polarization Modulation in Bi2MoO6 for Photocatalytic Performance Enhancement under Visible‐Light Illumination
Authors: Chen Yan , Yang Weiyi , Gao Shuang , Zhu Linggang , Sun Caixia , Li Qi 
Published: March 2018

AbstractA built‐in electric field from polarization inside polar photocatalysts could provide the driving force for photogenerated electrons and holes to move in opposite directions for better separation to improve their photocatalytic performance. The photocatalytic performance of a polar photocatalyst of Bi2MoO6 has been enhanced through the precise control of its structure to increase internal polarization. DFT calculations predicted that a shortened crystal lattice parameter b in Bi2MoO6 could induce larger internal polarization, which was achieved by the modulation of the pH of the reaction solution during a solvothermal synthetic process. A series of Bi2MoO6 samples were created with reaction solutions of pH≈1, 4, and 8; the crystal lattice parameter b was found to decrease gradually with increasing solution pH. Accordingly, these Bi2MoO6 samples demonstrated a gradually enhanced photocatalytic performance with decreasing crystal lattice parameter b, as demonstrated by the photocatalytic degradation of sulfamethoxazole/phenol and disinfection of Staphylococcus aureus bacteria under visible‐light illumination due to improved photogenerated charge‐carrier separation. This study demonstrates an innovative design strategy for materials to further enhance the photocatalytic performance of polar photocatalysts for a broad range of technical applications.
Determining preferred spawning habitat of the endangered Rio Grande silvery minnow by hydrological manipulation of a conservation aquaculture facility and the implications for management
Authors: Hutson Alison M. , Toya Louie A. , Tave Douglas 
Published: March 2018

AbstractThe endangered Rio Grande silvery minnow (Hybognathus amarus) was induced to spawn in both 2012 and 2013, using hydrological manipulation of a conservation aquaculture facility to create floodplain habitat. Fish responded to the flood by leaving the stream and entered both deep (20–97 cm) and shallow (14–18 cm) low‐velocity off‐channel habitats, spawning in the deep ones; fish did not spawn in the stream. When water level was brought down from flood stage, fry actively moved into the stream 2.5 weeks postspawn. This study supports the hypothesis that this species is a floodplain spawner. The results show that habitat restoration of the Rio Grande to create floodplains is needed for recovery of this species as floodplains are both spawning and nursery habitats. The study provides guidelines about how deep floodplain inundation must inundate for spawning to occur and for the duration of inundation so fry can actively swim with the water when flood waters recede. This project also shows that a conservation facility can be used for all stages of fish's life history. Equally important, it shows that a conservation aquaculture facility can be used to conduct hydrological experiments to determine how an endangered fish will respond to changes in river management.
Synthesizing models useful for ecohydrology and ecohydraulic approaches: An emphasis on integrating models to address complex research questions
Authors: Brewer Shannon K. , Worthington Thomas A. , Mollenhauer Robert , Stewart David R. , McManamay Ryan A. , Guertault Lucie , Moore Desiree 
Published: March 2018

AbstractEcohydrology combines empiricism, data analytics, and the integration of models to characterize linkages between ecological and hydrological processes. A challenge for practitioners is determining which models best generalizes heterogeneity in hydrological behaviour, including water fluxes across spatial and temporal scales, integrating environmental and socio‐economic activities to determine best watershed management practices and data requirements. We conducted a literature review and synthesis of hydrologic, hydraulic, water quality, and ecological models designed for solving interdisciplinary questions. We reviewed 1,275 papers and identified 178 models that have the capacity to answer an array of research questions about ecohydrology or ecohydraulics. Of these models, 43 were commonly applied due to their versatility, accessibility, user‐friendliness, and excellent user‐support. Forty‐one of 43 reviewed models were linked to at least 1 other model especially: Water Quality Analysis Simulation Program (linked to 21 other models), Soil and Water Assessment Tool (19), and Hydrologic Engineering Center's River Analysis System (15). However, model integration was still relatively infrequent. There was substantial variation in model applications, possibly an artefact of the regional focus of research questions, simplicity of use, quality of user‐support efforts, or a limited understanding of model applicability. Simply increasing the interoperability of model platforms, transformation of models to user‐friendly forms, increasing user‐support, defining the reliability and risk associated with model results, and increasing awareness of model applicability may promote increased use of models across subdisciplines. Nonetheless, the current availability of models allows an array of interdisciplinary questions to be addressed, and model choice relates to several factors including research objective, model complexity, ability to link to other models, and interface choice.
Consumption of terrestrial organic matter in the rocky intertidal zone along the central Oregon coast
Authors: Fairbanks Douglas O. , McArthur J Vaun , Young Craig M. , Rader Russell B. 
Published: March 2018

AbstractTerrestrial organic matter (TOM) constitutes an important source of energy in many aquatic environments. This is the first study to compare the consumption of terrestrial leaves (Alnus rubra) to high‐quality (Nereocystis luetkeana) and low‐quality (Fucus gardneri) sources of drift kelp and low‐quality seagrass (Phyllospadix spp.) in pools of the rocky intertidal zone on Cape Arago, Oregon, USA. On average, 1.02 kg ash‐free dry mass (AFDM) per day of TOM was transported by small forested streams during fall leaf abscission to the rocky intertidal zone in small pocket bays. Leaves of A. rubra (red alder) varied in wrack from negligible (12 g AFDM/m2) on some beaches to the primary source of detritus on others (256 g AFDM/m2). Long‐term feeding experiments (months) showed that consumption rates of A. rubra in the spring (19.7% of the initial pack biomass) and in the fall (52% of the initial pack biomass) were intermediate between those of N. luetkeana (fully consumed) and Phyllospadix spp. (never >10% consumed of the initial pack biomass). Long‐term experiments also showed that conditioned fall‐shed leaves of A. rubra were consumed at a faster rate (52.3% of initial pack biomass) than spring‐shed leaves of A. rubra (16.8% of initial pack biomass). Short‐term feeding experiments again showed that consumption of A. rubra in the spring (18.6% of initial pack biomass over 3 d) and fall (16.7% over 7 d) was intermediate between N. luetkeana (57.3% consumed over 3 d in the spring and 60.7% over 7 d in the fall) and Phyllospadix spp. (<1% consumed in the spring). Except for Phyllospadix spp., consumption rates followed polyphenolic concentrations in that, N. luetkeana (418 mg/mL) > A. rubra (3415 mg/mL) > F. gardneri (8098 mg/mL). Phyllospadix spp. was rarely consumed despite a fairly low concentration of phenolics (800 mg/mL). In the temperate zone, leaves of A. rubra may constitute an important source of energy during the fall and winter when more nutritious marine resources dieback, such as single‐celled algae and kelp (e.g., N. luetkeana).
A Sensitive Photoelectrochemical Aptasensor for miRNA‐21 Based on the Sensitization Effect of CdSe Quantum Dots
Authors: Cong Xinxin , Zhou Minfeng , Hou Ting , Xu Zijian , Yin Yizhi , Wang Xiaolei , Yin Miao 
Published: March 2018

AbstractA novel photoelectrochemical aptasensor for the sensitive detection of miRNA‐21 was designed based on the sensitization effect of CdSe quantum dots as a signal amplification strategy. The TiO2NTs/RGO/AuNPs electrode was prepared by the electrodeposition of graphene oxide and Au nanoparticles on TiO2 nanotubes with electrochemical reduction. The electrode was prepared as the matrix of the electrochemical aptasensor. The hairpin DNA strands decorated with CdSe quantum dots were immobilized on the surface of the electrode by Au−S bonds. Because of the card‐type structure of the hairpin DNA (HP‐DNA), the CdSe quantum dots were close to the base electrode, which would lead to the sensitization effect and cause the increase of the photocurrent intensity. When a certain concentration of the miRNA‐21 was added, miRNA‐21 hybridized with the complementary part of the HP‐DNA. At the same time, the hairpin structure of HP‐DNA was broken into a straight chain structure, so the CdSe quantum dots on the end of the DNA would move away from the electrode surface, the sensitization effect would be weakened, and the photocurrent intensity would be decreased. The designed photoelectrochemical aptasensor exhibited a low detection limit of 5.6 fM and a wide linear range from 20 fM to 0.2 nM, and it also showed good specificity, reproducibility and stability. The signal amplification strategy was also expected to provide a significant photoelectrochemical biosensor platform for the sensitive detection of biomolecules.
Capillary electrophoresis method for the discrimination between natural and artificial vanilla flavor for controlling food frauds
Authors: Lahouidak Samah , Salghi Rachid , Zougagh Mohammed , Ríos Angel 
Published: March 2018

AbstractA capillary electrophoresis method was developed for the determination of coumarin (COUM), ethyl vanillin (EVA), p‐hydroxybenzaldehyde (PHB), p‐hydroxybenzoic acid (PHBA), vanillin (VAN), vanillic acid (VANA) and vanillic alcohol (VOH) in vanilla products. The measured concentrations are compared to values obtained by liquid chromatography (LC) method. Analytical results, method precision, and accuracy data are presented and limits of detection for the method ranged from 2 to 5 μg/mL. The results obtained are used in monitoring the composition of vanilla flavorings, as well as for confirmation of natural or non‐natural origin of vanilla in samples using four selected food samples containing this flavor.
Dependence of sediment sorting on bedload transport phase in a river meander
Authors: Rovira Albert , Núñez‐González Francisco , Ibañez Carles 
Published: March 2018

AbstractIt is widely recognized nowadays that there are at least two different phases of bedload sediment transport in gravel‐bed rivers. However, the transition between these phases is still poorly or subjectively defined, especially at bends in rivers, where cross‐stream sediment transport can strongly influence changes in the texture of the transported sediment. In this paper, we use piecewise models to identify objectively, at two points in the cross‐section of a river bend, the discharge at which the transition between bedload transport phases occurs. Piecewise models were applied to a new bedload data set collected during a wide range of discharges while analysing the associated changes in sediment texture. Results allowed the identification of two well‐differentiated phases of sediment transport (phase I and phase II), with a breakpoint located around bankfull discharge. Associated with each phase there was a change in bedload texture. In phase I there was non‐dominance in the transport of fine or coarse fractions at a particular sampling point; but in phase II bedload texture was strongly linked to the position of the sampling point across the channel. In this phase, fine particles tended to be transported to the inner bank, while coarse sizes were transferred throughout the middle parts of the channel. Moreover, bedload texture at the inner sampling point became bimodal while the transport of pebble‐sized particles was increasing in the central parts of the river channel. It is suggested that this general pattern may be related both to secondary currents, which transfer finer particles from the outer to the inner bank, and to the progressive dismantling of the riverbed surface layer. Copyright © 2018 John Wiley & Sons, Ltd.
Simulating a century of soil erosion for agricultural catchment management
Authors: Smith Hugh G. , Peñuela Andrés , Sangster Heather , Sellami Haykel , Boyle John , Chiverrell Richard , Schillereff Daniel , Riley Mark 
Published: March 2018

AbstractAgricultural land management requires strategies to reduce impacts on soil and water resources while maintaining food production. Models that capture the effects of agricultural and conservation practices on soil erosion and sediment delivery can help to address this challenge. Historic records of climatic variability and agricultural change over the last century also offer valuable information for establishing extended baselines against which to evaluate management scenarios. Here, we present an approach that combines centennial‐scale reconstructions of climate and agricultural land cover with modelling across four lake catchments in the UK where radiometric dating provides a record of lake sedimentation. We compare simulations using MMF‐TWI, a catchment‐scale model developed for humid agricultural landscapes that incorporates representation of seasonal variability in vegetation cover, soil water balance, runoff and sediment contributing areas. MMF‐TWI produced mean annual sediment exports within 9–20% of sediment core‐based records without calibration and using guide parameter values to represent vegetation cover. Simulations of land management scenarios compare upland afforestation and lowland field‐scale conservation measures to reconstructed historic baselines. Oak woodland versus conifer afforestation showed similar reductions in mean annual surface runoff (8–16%) compared to current moorland vegetation but a larger reduction in sediment exports (26–46 versus 4–30%). Riparian woodland buffers reduced upland sediment yields by 15–41%, depending on understorey cover levels, but had only minor effect on surface runoff. Planting of winter cover crops in the lowland arable catchment halved historic sediment exports. Permanent grass margins applied to sets of arable fields across 15% or more of the catchment led to further significant reduction in exports. Our findings show the potential for reducing sediment delivery at the catchment scale with land management interventions. We also demonstrate how MMF‐TWI can support hydrologically‐informed decision making to better target conservation measures in humid agricultural environments. Copyright © 2018 John Wiley & Sons, Ltd.
Toxicity of various road-deicing salts to Asian clams (Corbicula fluminea)
Authors: Coldsnow Kayla D. , Relyea Rick A. 
Published: March 2018

Abstract

Humans are altering environments by destroying habitats, introducing species, and releasing pollution. One emergent pollutant is the salinization of freshwater habitats from road-deicing salts. Government agencies have set thresholds to protect freshwater ecosystems, yet these values are exceeded in many systems. The present study investigated the tolerance of Asian clams (Corbicula fluminea), a common invasive bivalve, to the common road salt (sodium chloride [NaCl]) and 2 alternatives (magnesium chloride [MgCl2] and calcium chloride [CaCl2]). Experiments conducted at 4 and 8 d revealed that Asian clams are very salt tolerant. The median lethal concentration after 4 d of exposure (LC504-d) estimate was 2162 mg Cl–/L for MgCl2, 3554 mg Cl–/L for CaCl2, and more than 22 581 mg Cl–/L for NaCl, which were all significantly different from each other (p ≤ 0.05). The LC508-d values were significantly different (p ≤ 0.05) from each other and from the LC504-d values, and were estimated to be 1769 mg Cl–/L for MgCl2, 2235 Cl–/L for CaCl2, and 10 069 mg Cl–/L for NaCl. Mortality was determined using 2 methods: either no response after exposure or no response after being in freshwater following exposure. For the majority of the LC50s, these methods were not significantly different (p &gt; 0.05). The high salt tolerance of Asian clams is a concern because of their transportation in ballast water between aquatic ecosystems. Furthermore, salt-tolerant organisms may outcompete sensitive organisms in salinized ecosystems, which may alter ecosystem services. Environ Toxicol Chem 2018;37:1839–1845. © 2018 SETAC