bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of reaction parameters on the preparation of P4VP/SiO2 composite aerogel via supercritical CO2 drying
Authors: Yang Xule , Wang Wei , Cao Liqin , Wang Jide 
Published: April 2019

AbstractHerein, crosslinked poly (4‐vinylpyridine)/SiO2 (P4VP/SiO2) composite aerogel, an organic‐inorganic interpenetrating network, was successfully prepared by means of the sol‐gel process, acid‐base interaction method, and supercritical CO2 drying process. In this novel composite aerogel, SiO2 was used as an inorganic material, and nitrogen‐containing heterocyclic polymer was used as the active component. The effects of aging time, monomer ratios, solvent usage, and cross‐linker ratios were analyzed to obtain the optimal conditions for the P4VP/SiO2 aerogel formation. The as‐prepared aerogel was characterized by using FT‐IR, XRD, Brunauer‐Emmett‐Teller (BET) analysis, and SEM analysis. Results showed that the aging time of 48 h, tetraethoxysilane (TEOS)/4‐vinylpyridine (4‐VP) mass ratio of 2:1, and diethylene glycol dimethacrylate (DEGDMA) content lower than 20 wt% were required to ensure the best porous amorphous structure of the product. These optimal conditions endowed the product with a relative high BET specific area (314 m2/g) and a low density (0.12 g/cm3). The adsorption performance of P4VP/SiO2 was investigated via its capacity to remove Cu(II) from wastewater. Results showed that the adsorption capacity of up to 85 mg/g was attained under neutral conditions and the adsorption process highly follows the pseudo‐second‐order kinetics model.
The influence of steric configuration of phenazine‐1‐carboxylic acid‐amino acid conjugates on fungicidal activity and systemicity
Authors: Zhu Xiang , Yu Linhua , Hsiang Tom , Huang Di , Xu Zhihong , Wu Qinglai , Du Xiaoying , Li Junkai 
Published: April 2019

AbstractBACKGROUNDConjugating an amino acid onto existing fungicidal parent structures has been demonstrated to be an effective way to endow non‐phloem mobile fungicides with phloem mobility. To alter the systemicity of the fungicide PCA (phenazine‐1‐carboxylic acid), 10 amino acids derivatives of this fungicide were designed and synthesized, and their synthesis, characterization, phloem and xylem mobility in Ricinus communis L, and their fungicidal activity in vitro are described.RESULTSThe systemicity experiments in Ricinus communis system demonstrated that all conjugates exhibited obvious phloem mobility compared with non‐phloem‐mobile PCA, and the introduction of an L‐amino acid to PCA more greatly enhanced the phloem mobility. The five D‐amino acid conjugates exhibited higher xylem mobility than that of PCA and of each corresponding L‐amino acid conjugate. Most conjugates were found to exhibit moderate in vitro fungicidal activities against six pathogenic fungi, which were lower than that of PCA. The results of the bioassay showed fungicidal activities of PCA‐amino acid conjugates associated not only with different amino acids, but also with their conformation. Conjugation with D‐amino acid contributed to the in vitro fungicidal activities of PCA‐amino acid conjugates.CONCLUSIONSThe current research offers a new strategy for enhancing the systemicity of non‐phloem‐mobile fungicides and presents some useful information on the effects of introducing amino acids of different steric configurations on the fungicidal activity, phloem and xylem mobility of the parent fungicide. © 2019 Society of Chemical Industry
Iron‐Catalyzed Regioselective C5‐H Benzylation of 8‐Aminoquinolines with Benzylic Acetates
Authors: Niu Tian‐Jing , Xu Jin‐Di , Ren Bao‐Zeng , Liu Jing‐Hui , Hu Guo‐Qin 
Published: April 2019

AbstractA Fe‐catalyzed C5‐H benzylation reaction of 8‐amidoquinoline amides has been developed by employing cheap, abundant benzylic acetates as benzyl sources. This method showcases excellent functional group compatibility and is applicable for gram‐scale synthesis or late‐stage diversification. Thus it provides an easy access to the corresponding C5‐benzylated quinoline derivatives.
Enhanced Charge Transfer Process of Bismuth Vanadate Interleaved Graphitic Carbon Nitride Nanohybrids in Mediator‐Free Direct Z Scheme Photoelectrocatalytic Water Splitting
Authors: Murugan Chinnan , Abinav Nataraj Ramakrishnan , Praveen Kumar Murugesan , Ravichandran Subbiah , Pandikumar Alagarsamy 
Published: April 2019

AbstractIn the present work, graphitic carbon nitride‐bismuth vanadate (g‐C3N4‐BiVO4) nanohybrid materials with different wt. % of g‐C3N4 were successfully synthesized by a simple hydrothermal method and characterized by UV‐Visible diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PLS), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectroscopy (FT‐IR), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray (EDAX) absorption spectroscopy, high‐resolution transmission electron microscopy (HR‐TEM) and selected area electron diffraction (SAED) analysis. The photoelectrocatalytic performance of g‐C3N4‐BiVO4 nanohybrid materials were investigated by water splitting under AM 1.5G (100 mWcm−2) illumination. The g‐C3N4‐BiVO4 photoanode with 10 wt. % of g‐C3N4 exhibited higher photoelectrocatalytic activity towards water splitting, which was 1.6 and 2.8‐folds higher than that of the pure BiVO4 and g‐C3N4, respectively. The remarkably enhanced photoelectrocatalytic activity of the nanohybrid is due to the efficient photogenerated electron‐hole separation through Z‐scheme mechanism, enhanced interfacial charge transfer process and suppression in the charge recombination rate. Hence, the g‐C3N4‐BiVO4 nanohybrid materials can be potential candidates for light harvesting applications.
Synthesis, Experimental and Theoretical Characterization of Novel Pyrimidine‐5‐Carboxamides
Authors: Gümüş Mehmet , Sert Yusuf , Yalkın Ahmet , Gökce Halil , Koca İrfan 
Published: April 2019

AbstractEight series of pyrimidine‐5‐carboxamides were synthesized and characterized by FT‐IR, 1H NMR, 13C NMR spectroscopies, HR‐MS and elemental analysis. To encourage experimental confirmations, molecular electronic structure calculations and harmonic vibrational frequencies of compounds (theoretical computations) were carried out with the DFT/B3LYP method at the 6–311G++(d,p) basis set. The selected important assignments‐computed harmonic vibrational wavenumbers of compounds were defined by using potential energy distribution (PED) analysis. The molecular electrostatic potential (MEP) surface analysis was examined to bring into the open nucleophilic and electrophilic reactive areas of the compounds. The highest occupied molecular orbitals and lowest unoccupied molecular orbitals (HOMOs and LUMOs) analyses were theoretically used for definition of electronic transitions corresponding to UV‐Vis. electronic absorption wavelengths. Additionally, for these series non‐linear optical properties (NLO) were investigated based on urea. Finally, in this manuscript molecular docking studies between macromolecule (receptor) and ligand interactions were carried out by using AutoDock Vina program. Obtained all outputs of new compounds were explained in different sections in‐depth.
Base‐Mediated Transition‐Metal‐Free Dehydrative C−C and C−N Bond‐Forming Reactions from Alcohols
Authors: Porcheddu Andrea , Chelucci Giorgio 
Published: April 2019

AbstractIn recent years, there has been an increasing interest in using alcohols as alkylating agents for C−C and C−N bond‐forming processes employing mainly TM‐catalysts. Although BH‐catalysis looks like a green atom economy process since water is the only by‐product, it often suffers from one or more drawbacks, such as the use of expensive noble metal complexes, capricious ligands, and toxic organic solvents. Therefore, straightforward, efficient, atom economy and environmentally benign alternative protocols are desirable. This review aims to summarize the current knowledge within the published literature about dehydrative processes developed without TM‐catalysts. The most recent contributions to this topic have been reviewed keeping into account the new findings reported in this area. The features, strengths, and limitations of these alcohol‐based C−C and C−N bond‐forming processes has also been taken into account.
Challenges to the sustainability of climate services in Europe
Authors: Bruno Soares Marta , Buontempo Carlo 
Published: April 2019

AbstractClimate services have emerged as a research and operational field in recent years. This development has been underpinned and supported by significant research, funding and agenda‐setting efforts such as the Global Framework for Climate Services internationally and the Roadmap for Climate Services and the Copernicus Climate Change Service in Europe. The fast pace at which this field is developing raises a number of key challenges that need to be critically examined and addressed to ensure the future development and sustainability of climate services in Europe. This opinion piece highlights a number of challenges currently threatening the viability of climate services including the complexity of the concept of climate services; the complex landscape of complementary research and development areas relevant to climate services; existing rights to freely access and use climate services; current limitations to funding structures and mechanisms and how that impacts on the development of climate services; the emphasis on co‐production as a precondition to climate services development; and the limited role of the social sciences in the research and operational field of climate services. Effectively addressing these challenges will require a commitment from the scientific and practitioner communities to engage in critical and reflective debates around the future conceptualization and operationalization of climate services in Europe. This paper aims to provide critical input to stimulate a necessary and overdue debate around the sustainability and future of climate services in Europe.This article is categorized under:

Social Status of Climate Change Knowledge > Knowledge and Practice
Surface effect on a nano‐elliptical hole or nano‐crack in magnetoelectroelastic materials under antiplane shear
Authors: Liu YunZheng , Guo JunHong , Zhang XiaoYan 
Published: April 2019

AbstractBased on the Gurtin‐Murdoch surface/interface model, an antiplane shear problem of a magnetically and electrically impermeable nano‐elliptical hole in magnetoelectroelastic (MEE) materials with surface effect is presented subjected to far‐field anti‐plane mechanical and in‐plane electrical and magnetic loadings. By using the complex function method and conformal mapping technique, exact closed‐form solutions of the stress, electric displacement and magnetic induction intensity factors near the crack tip are obtained when the nano‐elliptical hole is reduced to a nano‐crack. Numerical examples are provided to show the effects of size of nano‐crack on the field intensity factors near the crack tip induced by mechanical, electrical and magnetic loadings for the piezoelectric (PE), piezomagnetic (PM) and MEE materials with surface effect. The interaction between the stress field, electric field and magnetic field around the nano‐hole is analyzed. The results show that the obtained solution is close to the classical elasticity solution with increasing size of the nano‐crack.
Populist constitutionalism and constituent power
Authors: Doyle Oran 
Published: April 2019

AbstractConstituent power is a helpful component of constitutional theory because it provides a conceptual and potentially normative explanation of how a new constitution can be made without any existing legal authority to do so. Contemporary theories of constituent power, however, unhelpfully treat constituent power as a fictive entity, typically the people, that subsists through time. This predominant account of constituent power fails adequately to explain examples of constitution-making and also lends support to the populist claim that a unitary and unchanging people has an immanent but continuing role as a constitutional actor superior to the constitution itself. This enables populist leaders to rely on prevalent understandings of constitutionalism to support the sidestepping and/or removal of constraints on their power. In this Article, I trace the connections between mainstream theories of constituent power and the academically peripheral claims of populist constitutionalism. I argue for a different understanding of constituent power as a capacity that, in principle, may momentarily be exercised by any entity. This explains how a new constitution can unlawfully replace a pre-existing constitution yet come to have lawful authority itself, without implying the diachronic existence of the constituent power as an entity. I illustrate this understanding of constituent power with reference to the constitutional development of Taiwan and Ireland. These examples show—contrary to the predominant account of constituent power—that constitutional systems may be created without the exercise of constituent power and that constitutional law can play an important role in constructing an entity capable of exercising constituent power. Seen in this way, popular references in preambles are important not for their account of how a constitution was made but rather for their account of whom a constitution is for. This account of constituent power undermines core claims of populist constitutionalism. But it also provides a salutary lesson for liberal constitutionalists: a constitution adopted for a people must broadly serve the interests of that people.
Populism, authoritarianism and constitutionalism
Authors: Halmai Gábor 
Published: April 2019

AbstractThe paper deals with the relationship of different types of populism with authoritarianism and constitutionalism. In the first part, I try to define various approaches—Left and Right-Wing, “good” or “bad”—to populism, especially from the point of view of whether they aim at changing the liberal democratic constitutional system to an authoritarian one. The following part discusses the rhetoric of authoritarian populists, which makes this type of populism distinct from non-populist authoritarians. The paper also explores the question of whom to blame for the success of authoritarian populisms, and the final part investigates, whether the use of legal tools by an authoritarian populist to dismantle liberal constitutional democracies means that we can speak about a special populist constitutionalism. While the paper tries to find out the joint characteristics of authoritarian populism, it heavily relies on the Hungarian experiences as a kind of model approach in East-Central Europe and maybe even beyond.
The complacency of legality: Constitutionalist vulnerabilities to populist constituent power
Authors: Scholtes Julian 
Published: April 2019

AbstractWhat role do public law and liberal constitutionalism play in an era of political populism? This article approaches this question by exploring the concept of constituent power in the light of recent constitutional developments in countries with populist governments. It attempts to outline and contrast conceptions of constituent power as inherent in liberal constitutionalist and populist thinking, respectively. While constitutionalists draw heavily upon Kelsenian normativism in framing the way political power is generated, populists juxtapose this with a concept of constituent power that is inspired by Carl Schmitt’s ‘decisionist’ view. The complacency of legality inherent in liberal constitutionalist thinking is susceptible to a populist challenge that draws attention to the necessity for the social embeddedness of any legal order. Populism, it is argued, exposes a core tension inherent in constitutionalism: How do constitutionalists reconcile their democratic aspirations with the simultaneous preclusion of certain political choices from the democratic realm? Populists can attack constitutionalism also because of the deficient conception of constituent power that underlies the latter. The article concludes that, where challenged by populists, public law can at some point no longer rely on its own force to defend itself. Its authority needs to be re-established from an extra-legal, pre-positive perspective. In an era of political populism, constitutionalist public law becomes a discourse that can challenge populism by means of the powerful reasons that inhere in the former.
APARTMENT COMPOUNDS, HOUSEHOLDS, AND POPULATION IN THE ANCIENT CITY OF TEOTIHUACAN, MEXICO
Authors: Smith Michael E. , Chatterjee Abhishek , Huster Angela C. , Stewart Sierra , Forest Marion 
Published: April 2019

AbstractWe present three new analyses of existing data from past fieldwork at Teotihuacan. First, we confirm and refine the wealth-based housing typology of Millon's Teotihuacan Mapping Project (TMP). Second, we analyze the spatial configurations of excavated compounds, using network methods to identify the size and layout of individual dwellings within walled compounds. Third, we use those results to generate the first population estimate for the city based on measurements from the TMP map. We extrapolate the average sizes of dwellings from excavated compounds to the entire sample of mapped residences as depicted on the TMP map of the city. We generate a range of population estimates, of which we suggest that 100,000 persons is the most reasonable estimate for the Xolalpan-Metepec population of Teotihuacan. These analyses show that legacy data from fieldwork long past can be used to answer research questions that are relevant and important today.
The Effect of Ozone Shadowing on the D Region Ionosphere During Sunrise
Authors: Macotela Edith L. , Clilverd Mark A. , Manninen Jyrki , Thomson Neil R. , Newnham David A. , Raita Tero 
Published: April 2019

AbstractDiurnal very low frequency subionospheric radio wave phase measurements show a night‐to‐day transition pattern. During this sunrise transition a phase perturbation, which consist of a phase overshoot followed by a small phase recovery to normal daytime values, is often observed. The variability of the size of this sunrise phase perturbation and its maximum and end times were monitored to identify the associated physical causes. Very low frequency signal from the 22.1‐kHz UK transmitter (call sign GVT) recorded at Sodankylä, Finland, from 20 April 2010 to 31 December 2016 were used. The timing at the maximum of the phase perturbation period has an annual pattern that is well described by the seasonal variation of the sunrise time 28 km above the transmitter. Variations in ozone number density at 38–42‐km altitudes are better correlated (R = 0.7) with the sunrise phase perturbation variability than at any other altitudes below ~80 km, and exhibit higher correlation values than for atmospheric temperature. Our results show that the main characteristics of the observed very low frequency sunrise phase perturbation arise from shadowing of short‐wavelength solar UV flux from the D region ionosphere due to stratospheric ozone absorption.
STIL: a multi-function protein required for dopaminergic neural proliferation, protection, and regeneration
Authors: Li Lei , Liu Congcong , Carr Aprell L. 
Published: April 2019

AbstractDegeneration of dopaminergic (DA) neurons in the brain is the major cause for Parkinson’s disease (PD). While genetic loci and cellular pathways involved in DA neuron proliferation have been well documented, the genetic and molecular and cellular basis of DA cell survival remains to be elucidated. Recently, studies aimed to uncover the mechanisms of DA neural protection and regeneration have been reported. One of the most recent discoveries, i.e., multi-function of human oncogene SCL/TAL interrupting locus (Stil) in DA cell proliferation, neural protection, and regeneration, created a new field for studying DA cells and possible treatment of PD. In DA neurons, Stil functions through the Sonic hedgehog (Shh) pathway by releasing the inhibition of SUFU to GLI1, and thereby enhances Shh-target gene transcription required for neural proliferation, protection, and regeneration. In this review article, we will highlight some of the new findings from researches relate to Stil in DA cells using zebrafish models and cultured mammalian PC12 cells. The findings may provide the proof-of-concept for the development of Stil as a tool for diagnosis and/or treatment of human diseases, particularly those caused by DA neural degeneration.
Reliability of colour and hardness clinical examinations in detecting dentine caries severity: a systematic review and meta-analysis
Authors: Hon Larry , Mohamed Ahmed , Lynch Edward 
Published: April 2019

AbstractDental caries is the most common human infectious disease and is caused by microorganisms producing acids, resulting in changes in dental tissue hardness and colour. However, the accuracy and reliability of dentine colour and hardness as indicators for carious lesion severity has never been assessed in a systematic review. By applying strict criteria, only seven papers (five randomized control trials and two diagnostic studies) were considered for full text qualitative and quantitative assessment. Only three studies produced high quality evidence and only four articles were considered for meta-analysis, as these provided log10 colony forming units (CFU) data from caries biopsies following colour and hardness clinical examinations. When comparing the amount of CFU isolated from carious biopsies from different colour and hardness categories, hardness clinical examination was found to be a statistically more discriminate test than colour clinical examination. Therefore, hardness clinical examination is more specific and reliable than colour to detect dentine carious lesion severity. Further large carefully designed clinical studies are needed to consolidate the findings of this systematic review.
Chemical variability of artificial stone powders in relation to their health effects
Authors: Di Benedetto Francesco , Giaccherini Andrea , Montegrossi Giordano , Pardi Luca A. , Zoleo Alfonso , Capolupo Ferdinando , Innocenti Massimo , Lepore Giovanni O. , d’Acapito Francesco , Capacci Fabio , Poli Carla , Iaia Tonina Enza , Buccianti Antonella , Romanelli Maurizio 
Published: April 2019

AbstractThe occurrence of highly severe silica-related diseases among the resin- and silica-based artificial stone workers was claimed, associated to an extremely short latency. High levels of exposure and intrinsic properties of AS are thought to modulate the development of silicosis and auto-immune diseases. This study compares parent materials and processed dusts, to shed light on changes of AS occurring in the manufacturing process, through an XRF, EPR and XAS investigation. We point out the extremely wide variability of the materials, the occurrence of chemical signatures impressed by the processing techniques, and the unprecedented generation of stable radicals associated to the lysis of the Si-O chemical bond inside the resin coated respirable crystalline silica. These results suggest that the AS processing in industrial stone workshops can create respirable dusts with peculiar physical and chemical properties, to be correlated to the observed clinical evidences.