bluuebunny/crossref_metadata_2025_split huggingface dataset:
The plasmasphere electron content paradox
Authors: Krall J. , Huba J. D. 
Published: August 2016

AbstractMeasurements show that plasmasphere refilling rates decrease with increasing solar activity, while paradoxically, the vertical integration of the plasmasphere electron density (pTEC) increases with increasing solar activity. Using the Naval Research Laboratory SAMI2 (Sami2 is Another Model of the Ionosphere) and SAMI3 (Sami3 is Also a Model of the Ionosphere) codes, we simulate plasmasphere refilling following a model storm, reproducing this observed phenomenon. In doing so, we find that the refilling rate and resulting pTEC values are sensitive to the oxygen profile in the thermosphere and exosphere: the supply of H+ in the topside ionosphere is limited by the local O+ density, through
charge exchange. At solar minimum, the O+ supply simply increases with the O density in the exosphere. At solar maximum, we find that O‐O+ collisions limit the O+ density in the topside ionosphere such that it decreases with increasing O density. The paradox occurs because the pTEC metric gives electrons in the topside ionosphere more weight than electrons in the plasmasphere.
See Something, Do Something: Predicting Sexual Assault Bystander Intentions in the U.S. Military
Authors: Holland Kathryn J. , Rabelo Verónica Caridad , Cortina Lilia 
Published: August 2016

AbstractSexual assault is a pervasive problem in the U.S. military, especially against women. Bystander intervention is increasingly promoted as important for reducing sexual violence, and it may be particularly helpful in contexts with high rates of sexual violence. Bystander training encourages and enables people to intervene safely and stop sexual violence. In this study, we drew from an ecological model to investigate intrapersonal, microsystem, and exosystem factors that predicted Service members' assumption of personal responsibility to intervene in an alcohol‐involved sexual assault. Moreover, we examined how these predictors played a role in decisions about how to intervene: confronting the perpetrator, assisting the victim, or finding someone to help. We analyzed data from 24,610 active duty personnel collected by the Department of Defense. Several factors significantly related to Service members' bystander intentions: gender, rank, morale, attitudes about sexual assault, training, and trust in the military sexual assault system predicted the likelihood and method of bystander intervention. These findings help identify how and why people intervene (or fail to intervene) when they witness situations that could develop into sexual violence.
Accessing 2‐Arylbenzofurans by CuI2(pip)2‐Catalyzed Tandem Coupling/Cyclization Reaction: Mechanistic Studies and Application to the Synthesis of Stemofuran A and Moracin M
Authors: Qin Dan‐Dan , Chen Wei , Tang Xiao , Yu Wen , Wu An‐An , Liao Yi , Chen Hong‐Bin 
Published: August 2016

AbstractAn asymmetric dinuclear copper(I) complex, CuI2(pip)2 (pip=(2‐picolyliminomethyl)pyrrole anion), was used to catalyze the tandem coupling/cyclization reaction of o‐iodophenols and terminal alkynes, which led to the formation of valuable 2‐arylbenzofurans in good yields. DFT calculations showed that the two proximate copper atoms play cooperative roles throughout the catalytic cycle. Using this catalytic protocol, bioactive natural products stemofuran A and moracin M were concisely synthesized.
A Protonated Water Cluster as a Transient Proton‐Loading Site in Cytochrome c Oxidase
Authors: Supekar Shreyas , Gamiz‐Hernandez Ana P. , Kaila Ville R. I. 
Published: August 2016

AbstractCytochrome c oxidase (CcO) is a redox‐driven proton pump that powers aerobic respiratory chains. We show here by multi‐scale molecular simulations that a protonated water cluster near the active site is likely to serve as the transient proton‐loading site (PLS) that stores a proton during the pumping process. The pKa of this water cluster is sensitive to the redox states of the enzyme, showing distinct similarities to other energy converting proton pumps.
The First Synthesis of the Sterically Encumbered Adamantoid Phosphazane P4(NtBu)6: Enabled by Mechanochemistry
Authors: Shi Yan X. , Xu Kai , Clegg Jack K. , Ganguly Rakesh , Hirao Hajime , Friščić Tomislav , García Felipe 
Published: August 2016

AbstractAll reported attempts to synthesize the tert‐butyl‐substituted adamantoid phosph(III)azane P4(NtBu)6 have failed, leading to the classification of this molecule as inaccessible and a literature example of steric control in chemistry of phosphorus‐nitrogen compounds. We now demonstrate that this structure is readily accessible by a solvent‐free mechanochemical milling approach, highlighting the importance of mechanochemical reaction environments in evaluating chemical reactivity.
Enantioselective Generation of Adjacent Stereocenters in a Copper‐Catalyzed Three‐Component Coupling of Imines, Allenes, and Diboranes
Authors: Yeung Kay , Ruscoe Rebecca E. , Rae James , Pulis Alexander P. , Procter David J. 
Published: August 2016

AbstractA highly enantio‐ and diastereoselective copper‐catalyzed three‐component coupling affords the first general synthesis of homoallylic amines bearing adjacent stereocenters from achiral starting materials. The method utilizes a commercially available NHC ligand and copper source, operates at ambient temperature, couples readily available simple imines, allenes, and diboranes, and yields high‐value homoallylic amines that exhibit versatile amino, alkenyl, and boryl units.
Total Biosynthesis of Legionaminic Acid, a Bacterial Sialic Acid Analogue
Authors: Hassan Mohamed I. , Lundgren Benjamin R. , Chaumun Michael , Whitfield Dennis M. , Clark Brady , Schoenhofen Ian C. , Boddy Christopher N. 
Published: August 2016

AbstractLegionaminic acid, Leg5,7Ac2, a nonulosonic acid like 5‐acetamido neuraminic acid (Neu5Ac, sialic acid), is found in cell surface glycoconjugates of bacteria including the pathogens Campylobacter jejuni, Acinetobacter baumanii and Legionella pneumophila. The presence of Leg5,7Ac2 has been correlated with virulence in humans by mechanisms that likely involve subversion of the host's immune system or interactions with host cell surfaces due to its similarity to Neu5Ac. Investigation into its role in bacterial physiology and pathogenicity is limited as there are no effective sources of it. Herein, we construct a de novo Leg5,7Ac2 biosynthetic pathway by combining multiple metabolic modules from three different microbial sources (Saccharomyces cerevisiae, C. jejuni, and L. pneumophila). Over‐expression of this de novo pathway in Escherichia coli that has been engineered to lack two native catabolic pathways, enables significant quantities of Leg5,7Ac2 (≈120 mg L−1 of culture broth) to be produced. Pure Leg5,7Ac2 could be isolated and converted into CMP‐activated sugar for biochemical applications and a phenyl thioglycoside for chemical synthesis applications. This first total biosynthesis provides an essential source of Leg5,7Ac2 enabling study of its role in prokaryotic and eukaryotic glycobiology.
Fiscal Challenges for Australia: The Next Decade and Beyond
Authors: Daley John , Wood Danielle 
Published: August 2016

AbstractIn Australia, both the Commonwealth and state governments are running substantial budget deficits, and future challenges are likely to make these problems worse. This paper presents the key challenges facing these budgets. Falling terms of trade and lower nominal economic growth will drag on government revenues. Spending in health and infrastructure has grown faster than GDP. State government revenues are also affected by Commonwealth decisions to reduce grants to them. We also show how the government's short‐term and medium‐term projections rely on overly‐optimistic assumptions about organic revenue growth and spending restraint. As such, a drift back to surplus is unlikely and restoring budget sustainability will require Australian governments to make more politically difficult decisions. While containing spending is important, both the politics of budget repair and the sheer size of the budget gap means that they will not be able to bring their budgets to balance without also boosting revenues.
An Efficient Finite Difference Method for The Time‐Delay Optimal Control Problems With Time‐Varying Delay
Authors: Jajarmi Amin , Hajipour Mojtaba 
Published: August 2016

AbstractIn this paper, an efficient finite difference method is presented for the solution of time‐delay optimal control problems with time‐varying delay in the state. By using the Pontryagin's maximum principle, the original time‐delay optimal control problem is first transformed into a system of coupled two‐point boundary value problems involving both delay and advance terms. Then the derived system is converted into a system of linear algebraic equations by using a second‐order finite difference formula and a Hermite interpolation polynomial for the first‐order derivatives and delay terms, respectively. The convergence analysis of the proposed approach is provided. The new scheme is also successful for the optimal control of time‐delay systems affected by external persistent disturbances. Numerical examples are included to demonstrate the validity and applicability of the new technique. Some comparative results are included to illustrate the effectiveness of the proposed method.
Young adolescents' advertising literacy and purchase intention in social network games: Influence of perspective taking and need for cognition
Authors: Vanwesenbeeck Ini , Ponnet Koen , Walrave Michel 
Published: August 2016

AbstractSocial network games (SNGs) are popular online venues for young adolescents. The aim of this study is to examine how individual traits, need for cognition (NFC) and perspective taking (PT), are related to young‐adolescents' conceptual (i.e. understanding selling and persuasive intentions) and attitudinal (i.e. critical attitude) advertising literacy in these SNGs. The current study also examines how a child's conceptual and attitudinal advertising literacy is related to purchase intentions after seeing advertising in an SNG. In total, 781 young adolescents (aged 10–14 years) took part in our study. First, participants were shown a 5‐min video clip of an SNG including advertising. After watching the video clip, the participants completed a questionnaire about, among others, NFC, PT, conceptual advertising literacy, attitudinal advertising literacy and purchase intentions. NFC was found predictive of children's understanding of the selling and persuasive intent of SNG advertising. This means that children who score higher on the NFC scale are also more likely to have a higher conceptual knowledge of SNG advertising. PT was found to negatively influence children's critical attitude towards SNG advertising. As expected, critical attitude towards advertising was negatively related to purchase intentions. Finally, purchase intention was only partially related to conceptual advertising literacy. Copyright © 2016 John Wiley & Sons, Ltd.
Clinical report: variable phenotypic expression in a large sibling cohort with a deletion of 4p16.1
Authors: Guy Carrie , Wang Xianfu , Lu Xianglan , Lu Jin , Li Shibo 
Published: August 2016

Key Clinical MessageWe report a half‐sibling cohort with deletion of 4p16.1, astigmatism, gross and fine motor delay, variable intellectual disability, and variable behavioral concerns. However, two siblings without the deletion also had learning delays and psychological concerns. Thus, variable phenotypic expression was seen and the significance of deletion of 4p16.1 remains unclear.
Hierarchical Cu@MnO2 Core–shell Nanowires: A Nonprecious‐Metal Catalyst with an Excellent Catalytic Activity Toward the Reduction of 4‐Nitrophenol
Authors: Du Cheng , He Shuijian , Gao Xiaohui , Chen Wei 
Published: August 2016

AbstractA nonprecious catalyst of hierarchical Cu@MnO2 core–shell nanowires was fabricated by a facile hydrothermal route and the nanostructured material showed a high catalytic activity toward the reduction of 4‐nitrophenol in the presence of NaBH4. With an intact core–shell structure and porous MnO2 shell, the Cu@MnO2 nanowires exhibited an excellent catalytic activity with an activity factor of 571 s−1 g−1 and high recyclability with a conversion of 96 % after seven catalytic cycles.
Reaction of Paramagnetic Synthon, Lithiated 4,4,5,5‐Tetramethyl‐4,5‐dihydro‐1H‐imidazol‐1‐oxyl 3‐oxide, with Cyclic Aldonitrones of the Imidazole Series
Authors: Tolstikov Svyatoslav E. , Tretyakov Evgeny V. , Gorbunov Dmitry E. , Zhurko Irina F. , Fedin Matvey V. , Romanenko Galina V. , Bogomyakov Artem S. , Gritsan Nina P. , Mazhukin Dmitry G. 
Published: August 2016

AbstractIt was shown that dipole‐stabilized paramagnetic carbanion lithiated 4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazol‐1‐oxyl 3‐oxide can be attached in a nucleophilic manner to either isolated or conjugated aldonitrones of the 2,5‐dihydroimidazole 3‐oxide and 2H‐imidazole 1‐oxide series to afford adducts the subsequent oxidation of which leads to polyfunctional mono‐ and diradicals. According to XRD, at least two polymorphic modifications can be formed during crystallization of the resulting paramagnetic compounds, and for each of them, geometric parameters of the molecules are similar. An EPR spectrum of the diradical in frozen toluene has a complicated lineshape, which can be fairly well reproduced by using X‐ray diffraction structural analysis and the following set of parameters: D=14.9 mT, E=1.7 mT; tensor a(14N)=[0.260 0.260 1.625] mT, two equivalent tensors for the nitronyl nitroxide moiety a(14N)=[0.198 0.198 0.700] mT, and g≈2.007. According to our DFT and ab initio calculations, the intramolecular exchange in the diradical is very weak and most likely ferromagnetic.
Mechanism of Ligand‐Controlled Regioselectivity‐Switchable Copper‐Catalyzed Alkylboration of Alkenes
Authors: Xu Zheng‐Yang , Jiang Yuan‐Ye , Su Wei , Yu Hai‐Zhu , Fu Yao 
Published: August 2016

AbstractCu‐catalyzed alkylboration of alkenes with bis(pinacolato)diboron ((Bpin)2) and alkyl halides provides a ligand‐controlled regioselectivity‐switchable method for the construction of complex boron‐containing compounds. Here, we employed DFT methods to elucidate the mechanistic details of this reaction and the origin of the different regioselectivity induced by Xantphos and Cy‐Xantphos. The calculation results reveal that the catalytic cycle mainly proceeds through the migratory insertion of alkenes on Cu‐Bpin complex, the oxidative addition of alkyl halides, and the reductive elimination of a C−C bond. Meanwhile, the rate‐ determining step is the oxidative addition of alkyl halides and the regioselectivity‐determining step is the migratory insertion of alkenes. The bulky cyclohexyl group of Cy‐Xantphos facilitates the approach of the substituents of alkenes to Bpin in the migratory insertion step and thus leads to the Markovnikov products. The less bulky phenyl group on Xantphos prefers keeping the substituents of alkenes away from the Bpin moiety in the migratory insertion step and thus results in anti‐Markovnikov products.
[2+2+2] Cycloisomerisation of Aromatic Cyanodiynes in the Synthesis of Pyridohelicenes and Their Analogues
Authors: Klívar Jiří , Jančařík Andrej , Šaman David , Pohl Radek , Fiedler Pavel , Bednárová Lucie , Starý Ivo , Stará Irena G. 
Published: August 2016

AbstractWe have developed a methodology for the synthesis of pyridohelicenes and their analogues based on the Ni0‐, CoI‐ or RhI‐mediated intramolecular [2+2+2] cycloisomerisation of cyanodiynes. It allows for folding the linear precursors into the corresponding helical backbones comprising the newly formed pyridine unit in their central part. Along with racemic pyrido[n]helicenes (n=5,6,7) and their derivatives, both enantio‐ and diastereomerically pure pyrido[n]helicene‐like molecules (n=5,6) were prepared by employing the chiral substrate‐controlled cyclisation of the corresponding enantiopure cyanodiynes.
Hypervalent Pentafluoroethylgermanium Compounds, [(C2F5)nGeX5−n]− and [(C2F5)3GeF3]2− (X=F, Cl; n=2–5)
Authors: Pelzer Stefanie , Neumann Beate , Stammler Hans‐Georg , Ignat'ev Nikolai , Hoge Berthold 
Published: August 2016

AbstractThis paper gives an account on hypervalent fluoro‐ and chloro(pentafluoroethyl)germanium compounds. The selective synthesis of the tris(pentafluoroethyl)dichlorogermanate salt [PNP][(C2F5)3GeCl2] as well as its X‐ray structural analysis is described. As a representative example for pentafluoroethylfluorogermanates, the synthesis and structure of 2,4,6‐triphenylpyryliumtris(pentafluoroethyl)difluorogermanate [C23H17O][(C2F5)3GeF2] is reported. Fluoride‐ion affinities for pentafluoroethylgermanes were calculated using quantum chemical methods, disclosing (C2F5)3GeF as a weaker Lewis acid than (C2F5)3SiF or (C2F5)3PF2. The theoretical results were confirmed by experiments and give the basis of a synthetic protocol for (C2F5)3GeF. Pentakis(pentafluoroethyl)germanate [PPh4][Ge(C2F5)5] was detected as an intermediate during the synthesis of [PPh4][(C2F5)4GeF] starting from tris(pentafluoroethyl)difluorogermanate and LiC2F5.
Modelling particle growth under saturated and starved conditions in emulsion polymerization
Authors: Brunier Barthélémy , Sheibat‐Othman Nida , Othman Sami , Chevalier Yves , Bourgeat‐Lami Elodie 
Published: August 2016

AbstractModelling of particle growth under saturated and starved conditions in emulsion polymerization was investigated in order to allow describing the broadening of the particle size distribution and account for the effects of restricted diffusion inside the monomer‐swollen polymer particles. In emulsion polymerization, if particle nucleation and coagulation are avoided, the reaction proceeds as a consequence of radical capture, desorption, and termination reactions inside the particles. Therefore, first, investigation of radical entry and desorption models was done under saturation of polymer particles with monomer, where diffusion parameters are constant. The discrimination criterion of the different models was based on fitting the reaction and the total particle size distribution. Indeed, the broadening of the particle size distribution was found to reveal a dependency of radical capture on the particle size; such an effect would be misestimated if only the mean particle size is considered. Second, the models for starved conditions that account for the variation of radical diffusion inside the polymer particles, such as the gel and glass effects, were investigated with comparison to a wide variety of experimental conditions spanning from weak to strong gelation. The dominating mechanisms as well as the interests of both intervals are highlighted.
Lernwege zum Experimentieren beim Wettbewerb „Jugend forscht“
Authors: Paul Jürgen , Schanze Sascha , Groß Jorge 
Published: August 2016

AbstractFachgemäße Denk‐ und Arbeitsweisen stehen zunehmend im Zentrum des naturwissenschaftlichen Unterrichts und sind ein wichtiger Bereich fachdidaktischer Forschung. Die erklärte Absicht des Schülerwettbewerbs Jugend forscht ist, solche naturwissenschaftlichen Denk‐ und Arbeitsweisen wie das Experimentieren gezielt zu fördern. Auf der Grundlage von 57 Interviews mit am Wettbewerb teilnehmenden Jugendlichen fasst die vorliegende qualitative Studie die auftretenden Konzepte zum Experimentieren zusammen und leitet aus den Vorstellungsänderungen zugehörige Lernwege ab. Dabei lassen sich fünf verschiedene Lernweg‐Dimensionen erkennen, innerhalb derer Lernprozesse stattfinden können. Diese sind das Verfahren, der Zweck, die Materialien, die Kontrolle und die Zeit. Die erhobenen Vorstellungsänderungen führen die teilnehmenden Jugendlichen auf zwei wesentliche Ursachen zurück: (1) Auf die Möglichkeit, sehr nahe am realen naturwissenschaftlichen Erkenntnisweg zu arbeiten. (2) Auf die vielfältigen Austauschmöglichkeiten, welche eine bewusste Reflexion des eigenen Projekts fördern. Die Befunde legen eine stärkere Verankerung ergebnisoffener Experimente auch im Schulunterricht nahe.
Zwitterionic Polymer‐Coated Ultrasmall Superparamagnetic Iron Oxide Nanoparticles with Low Protein Interaction and High Biocompatibility
Authors: Pombo‐García Karina , Weiss Stephan , Zarschler Kristof , Ang Ching‐Seng , Hübner René , Pufe Johanna , Meister Sebastian , Seidel Jürgen , Pietzsch Jens , Spiccia Leone , Stephan Holger , Graham Bim 
Published: August 2016

AbstractWe report the synthesis and detailed in vitro evaluation of zwitterionic ultrasmall superparamagnetic iron oxide NPs (USPIONs) comprising oleic acid/oleyl alcohol‐stabilized magnetite particles (5 nm core diameter) coated with an amphiphilic zwitterionic polymer, poly(maleic anhydride‐alt‐1‐decene) substituted with 3‐(dimethylamino)propylamine (PMAL). These particles display a near‐neutral zeta potential at pH≥7 and possess high colloidal stability, maintaining a hydrodynamic diameter of ca. 15–20 nm over a wide range of pHs (4–10) and ionic strength (up to 1 m NaCl). They exhibit very low levels of nonspecific protein binding upon exposure to serum, and negligible uptake by phagocytic and non‐phagocytic hepatocarcinoma cells, which suggests that they may be able to resist rapid accumulation in the liver and spleen, a common in vivo fate for NPs. The PMAL‐USPIONs exhibit very low cytotoxicity and do not elicit an inflammatory response or display hemolytic activity in vitro. Minimal nonspecific uptake by either cancerous or non‐cancerous cell lines was observed, an important precondition to achieve highly selective targeting upon further functionalization with an active targeting agent (e.g., antibody or peptide). Overall, this study establishes the considerable potential of PMAL‐USPIONs as a platform for the future development of “stealth” NP‐based imaging and/or therapeutic agents.
From the Superatom Model to a Diverse Array of Super‐Elements: A Systematic Study of Dopant Influence on the Electronic Structure of Thiolate‐Protected Gold Clusters
Authors: Schacht Julia , Gaston Nicola 
Published: August 2016

AbstractThe electronic properties of doped thiolate‐protected gold clusters are often referred to as tunable, but their study to date, conducted at different levels of theory, does not allow a systematic evaluation of this claim. Here, using density functional theory, the applicability of the superatomic model to these clusters is critically evaluated, and related to the degree of structural distortion and electronic inhomogeneity in the differently doped clusters, with dopant atoms Pd, Pt, Cu, and Ag. The effect of electron number is systematically evaluated by varying the charge on the overall cluster, and the nominal number of delocalized electrons, employed in the superatomic model, is compared to the numbers obtained from Bader analysis of individual atomic charges. We find that the superatomic model is highly applicable to all of these clusters, and is able to predict and explain the changing electronic structure as a function of charge. However, significant perturbations of the model arise due to doping, due to distortions of the core structure of the Au13[RS(AuSR)2]6− cluster. In addition, analysis of the electronic structure indicates that the superatomic character is distributed further across the ligand shell in the case of the doped clusters, which may have implications for the self‐assembly of these clusters into materials. The prediction of appropriate clusters for such superatomic solids relies critically on such quantitative analysis of the tunability of the electronic structure.
Across the Board: Nam‐Gyu Park
Authors: Park Nam‐Gyu 
Published: August 2016

AbstractIn this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Prof. Nam‐Gyu Park, who highlights the recent work on mixed‐cation mixed‐anion perovskite materials toward high efficiency perovskite solar cells. He summarizes the work that has brought us to the current stage of research and suggests possible future paths for further advancement.