bluuebunny/crossref_metadata_2025_split huggingface dataset:
Further evidence for early lunar magnetism from troctolite 76535
Authors: Garrick‐Bethell Ian , Weiss Benjamin P. , Shuster David L. , Tikoo Sonia M. , Tremblay Marissa M. 
Published: December 2016

AbstractThe earliest history of the lunar dynamo is largely unknown and has important implications for the thermal state of the Moon and the physics of dynamo generation. The lunar sample with the oldest known paleomagnetic record is the 4.25 billion year old (Ga) troctolite 76535. Previous studies of unoriented subsamples of 76535 found evidence for a dynamo field with a paleointensity of several tens of microteslas. However, the lack of mutual subsample orientation prevented a demonstration that the magnetization was unidirectional, a key property of thermoremanent magnetization. Here we report further alternating field demagnetization on three mutually oriented subsamples of 76535, as well as new pressure remanent magnetization experiments to help rule out shock magnetization. We also describe new 40Ar/39Ar thermochronometry and cosmogenic neon measurements that better constrain the rock's thermal history. Although the rock is unbrecciated, unshocked, and slowly cooled, its demagnetization behavior is not ideal due to spurious remanence acquisition. Despite this limitation, all three subsamples record a high coercivity magnetization oriented in nearly the same direction, implying that they were magnetized by a unidirectional field on the Moon. We find no evidence for shock remanence, and our thermochronometry calculations show no significant reheating events since 4249 ± 12 million years ago (Ma). We infer a field paleointensity of approximately 20–40 μT, supporting the previous conclusion that a lunar dynamo existed at 4.25 Ga. The timing of this field supports an early dynamo powered by thermal or thermochemical core convection and/or a mechanical dynamo but marginally excludes a dynamo delayed by thermal blanketing from radiogenic element‐rich magma ocean cumulates.
Applicability of the ecosystem type approach to model permafrost dynamics across the Alaska North Slope
Authors: Nicolsky D. J. , Romanovsky V. E. , Panda S. K. , Marchenko S. S. , Muskett R. R 
Published: December 2016

AbstractThawing and freezing of Arctic soils is affected by many factors, with air temperature, vegetation, snow accumulation, and soil physical properties and soil moisture among the most important. We enhance the Geophysical Institute Permafrost Laboratory model and develop several high spatial resolution scenarios of changes in permafrost characteristics in the Alaskan Arctic in response to observed and projected climate change. The ground thermal properties of surface vegetation and soil column are upscaled using the Ecosystems of Northern Alaska map and temperature data assimilation from the shallow boreholes across the Alaska North Slope. Soil temperature dynamics are simulated by solving the 1‐D nonlinear heat equation with phase change, while the snow temperature and thickness are simulated by considering the snow accumulation, compaction, and melting processes. The model is verified by comparing with available active layer thickness at the Circumpolar Active Layer Monitoring sites, permafrost temperature, and snow depth records from existing permafrost observatories in the North Slope region.
Recent Advances in the Intramolecular Reactions of Epoxides with Arenes and Heteroarenes
Authors: Das Sajal Kumar 
Published: December 2016

AbstractOver the years, the reactions and applications of epoxides have attracted the attention of many research groups. Intramolecular reactions of epoxides with arenes, termed epoxide–arene cyclizations (EACs) in this Focus Review, are the intramolecular C−C bond‐forming reactions of arenes with tethered epoxides and represent a particular type of epoxide‐derivatization reactions. EACs have been successfully applied to the synthesis of various benzo‐fused carbo‐ and heterocycles as reliable C−C bond‐forming reactions with complete atom economy. In this Focus Review, results in the literature since 2011 on the development of EACs are presented. Different aspects of substrate reactivities, the regio‐ and stereochemical outcomes of these reactions, and their proposed mechanisms are discussed.
Hierarchical Mesoporous SnO2 Nanosheets on Carbon Cloth: A Robust and Flexible Electrocatalyst for CO2 Reduction with High Efficiency and Selectivity
Authors: Li Fengwang , Chen Lu , Knowles Gregory P. , MacFarlane Douglas R. , Zhang Jie 
Published: December 2016

AbstractElectrochemical reduction of CO2 into liquid fuels is a promising approach to achieve a carbon‐neutral energy cycle. However, conventional electrocatalysts usually suffer from low energy efficiency and poor selectivity and stability. A 3D hierarchical structure composed of mesoporous SnO2 nanosheets on carbon cloth is proposed to efficiently and selectively electroreduce CO2 to formate in aqueous media. The electrode is fabricated by a facile combination of hydrothermal reaction and calcination. It exhibits an unprecedented partial current density of about 45 mA cm−2 at a moderate overpotential (0.88 V) with high faradaic efficiency (87±2 %), which is even larger than most gas diffusion electrodes. Additionally, the electrode also demonstrates flexibility and long‐term stability. The superior performance is attributed to the robust and highly porous hierarchical structure, which provides a large surface area and facilitates charge and mass transfer.
Hydrothermal Carbon Enriched with Oxygenated Groups from Biomass Glucose as an Efficient Carbocatalyst
Authors: Wen Guodong , Wang Bolun , Wang Congxin , Wang Jia , Tian Zhijian , Schlögl Robert , Su Dang Sheng 
Published: December 2016

AbstractMetal‐free carbocatalysts enriched with specific oxygenated groups with different morphology and size were synthesized from glucose by hydrothermal carbonization, in which cheap and widely available biomass could be converted into functionalized carbon using an environmentally benign process. The hydroxy‐ and carbonyl‐enriched hydrothermal carbon (HTC) could be used in nitrobenzene reduction, and higher conversion was obtained on the sphere morphology with smaller size. In the Beckmann rearrangement of cyclohexanone oxime, carboxyl‐enriched HTC exhibited superior performance compared with conventional solid acid (such as HY and HZSM‐5), on which the strong acid sites and weak Lewis acid sites lead to high selectivity for the side product. Although the intrinsic acidity of carbon is weak, the carboxyl‐enriched carbon was used in weak Brønsted acid‐catalyzed reactions, such as the Beckmann rearrangement.
Markovnikov‐Selective Radical Addition of S‐Nucleophiles to Terminal Alkynes through a Photoredox Process
Authors: Wang Huamin , Lu Qingquan , Chiang Chien‐Wei , Luo Yi , Zhou Jiufu , Wang Guangyu , Lei Aiwen 
Published: December 2016

AbstractDirect radical additions to terminal alkynes have been widely employed in organic synthesis, providing credible access to the anti‐Markovnikov products. Because of the Kharasch effect, regioselective control for the formation of Markovnikov products still remains a great challenge. Herein, we develop a transition‐metal‐free, visible light‐mediated radical addition of S‐nucleophiles to terminal alkynes, furnishing a wide array of α‐substituted vinyl sulfones with exclusive Markovnikov regioselectivity. Mechanistic investigations demonstrated that radical/radical cross‐coupling might be the key step in this transformation. This radical Markovnikov addition protocol also provides an opportunity to facilitate the synthesis of other valuable α‐substituted vinyl compounds.
A Hydrogen‐Bonded Cyanide‐Bridged [Co2Fe2] Square Complex Exhibiting a Three‐Step Spin Transition
Authors: Nihei Masayuki , Yanai Yuta , Hsu I.‐Jui , Sekine Yoshihiro , Oshio Hiroki 
Published: December 2016

AbstractCo‐crystallization of a cyanide‐bridged tetranuclear complex [Co2Fe2] with 4‐cyanophenol (CP) gave a hydrogen bonding donor–acceptor system, [Co2Fe2(bpy*)4(CN)6(tp*)2](PF6)2⋅2 CP⋅8 BN (1). 1 exhibited a three‐step phase transition between HT, IM1, IM2, and LT phases upon temperature variation. Variable temperature magnetic measurements and structural analyses revealed that the three‐step spin transition is caused by electron‐transfer‐coupled spin transitions (ETCSTs) accompanied with alteration of the hydrogen bonding interactions.
Improving Robustness Filter Bandwidth in Repetitive Control by Considering Model Mismatch
Authors: Eielsen Arnfinn A. , Teo Yik R. , Fleming Andrew J. 
Published: December 2016

AbstractRepetitive control (RC) is used to track and reject periodic signals by including a model of a periodic signal in the feedback path. The performance of RC can be improved by including an inverse plant response filter, but due to modeling uncertainty at high frequencies, a low‐pass robustness filter is also required to limit the bandwidth of the signal model and ensure stability. The design of robustness filters is presently ad‐hoc, which may result in excessively conservative performance. This article proposes a new automatic method for designing the robustness filter based on convex optimization and an uncertainty model. Experimental results on a nanopositioning system demonstrate that the proposed method outperforms the traditional brick‐wall filter approach.
Capacity investment model for airport facilities under demand uncertainty
Authors: Sun Yanshuo , Schonfeld Paul M. 
Published: December 2016

SummaryThis paper addresses strategic airport facility planning under demand uncertainty. Existing studies are improved by (1) allowing capacity contraction and (2) adopting more flexible delay functions. A mixed‐integer nonlinear program, which incorporates scale economies in construction, time value of money, nonlinear congestion effect, and other factors, is proposed for optimizing the capacity expansion/contraction decisions over time for multiple airport components. The stochastic problem is converted into its deterministic equivalent because the number of demand scenarios considered is finite. A discrete approximation technique is used to remove the nonlinearities. Numerical studies are presented to demonstrate the capability of the proposed model and the computational efficiency of the solution method. The “Flaw of Averages” due to faulty decisions based on the average future condition is illustrated, and trade‐offs among various costs are discussed in the numerical analyses. Copyright © 2016 John Wiley & Sons, Ltd.
Physiologically based pharmacokinetic modeling revealed minimal codeine intestinal metabolism in first‐pass removal in rats
Authors: Noh Keumhan , Chen Shu , Yang Qi J. , Pang K. Sandy 
Published: December 2016

AbstractThe physiologically based model with segregated flow to the intestine (SFM‐PBPK; partial, lower flow to enterocyte region vs. greater flow to serosal region) was found to describe the first‐pass glucuronidation of morphine (M) to morphine‐3β‐glucuronide (MG) in rats after intraduodenal (i.d.) and intravenous (i.v.) administration better than the traditional model (TM), for which a single intestinal flow perfused the whole of the intestinal tissue. The segregated flow model (SFM) described a disproportionately greater extent of intestinal morphine glucuronidation for i.d. vs. i.v. administration. The present study applied the same PBPK modeling approaches to examine the contributions of the intestine and liver on the first‐pass metabolism of the precursor, codeine (C, 3‐methylmorphine) in the rat. Unexpectedly, the profiles of codeine, morphine and morphine‐3β‐glucuronide in whole blood, bile and urine, assayed by LCMS, were equally well described by both the TM‐PBPK and SFM‐PBPK. The fitted parameters for the models were similar, and the net formation intrinsic clearance of morphine (from codeine) for the liver was much higher, being 9‐ to 13‐fold that of the intestine. Simulations, based on the absence of intestinal formation of morphine, correlated well with observations. The lack of discrimination of SFM and TM with the codeine data did not invalidate the SFM‐PBPK model but rather suggests that the liver is the only major organ for codeine metabolism. Because of little or no contribution by the intestine to the metabolism of codeine, both the TM‐ and SFM‐PBPK models are equally consistent with the data. Copyright © 2016 John Wiley & Sons, Ltd.
Role of ABC transporters in trans‐epithelial transport of vitamin K antagonists
Authors: Espana Bernadette , Couturier Solange , Prouillac Caroline 
Published: December 2016

AbstractVitamin K antagonists (VKAs) remain the oral anticoagulant of choice in venous thromboembolic disease. These drugs are characterized by a large inter‐individual variability requiring frequent dose tailoring. Genetic polymorphisms for cytochrome CYP2C9 and VKORC1 explain some of the variability, especially in warfarin and acenocoumarol responses. The aim of this study was to assess, in cell models, the role of ABC transporters in the intestinal transfer of the main coumarin derivatives (warfarin, acenocoumarol) and indanedione derivatives (phenindione, fluindione). The results show a basal to apical polarized transport for fluindione, phenindione and acenocoumarol only. Experimental studies using specific inhibitors of transport protein demonstrate the implication of MRPs and BCRP proteins and to a lesser extent P‐gp. Warfarin and acenocoumarol seem to be poor inhibitors of MRPs protein, whereas fluindione and phenindione have a slight or no effect. The regulation of the expression of ABC transporters by exposure to VKAs was also investigated in Caco‐2 cells. The expression of mRNA P‐gp, MRP1, MRP2 and BCRP was weakly or not modified after 24 h of VKAs exposure. In conclusion, the intestinal transfer of indanedione derivatives and acenocoumarol could be influenced by transport proteins of the ABC superfamily. Coumarin derivatives are poor inhibitors of these proteins and AVKs have a slight effect on the mRNA ABC transporter expression level. Copyright © 2016 John Wiley & Sons, Ltd.
A Delphi study of effective practices for developing competency‐based learning models in higher education
Authors: McIntyre‐Hite Lisa 
Published: December 2016

BackgroundThere are over 600 universities developing competency‐based education (CBE) programs in response to student and employer desire to bridge the gap between academic outcomes and employer needs (Fain , https://www.insidehighered.com/news/2015/09/10/amid-competency-based-education-boom-meeting-help-colleges-do-it-right). However, research is still emerging on effective practices for developing CBE programs.MethodsThe purpose of this qualitative Delphi study was to gather expert opinions about effective practices for developing competencies, assessments, and learning resources in CBE programs in higher education. Ten specialists in developing CBE programs served as participants. Data from three rounds of interviews were coded and categorized, using Delphi methodology.FindingsEighteen principles for effective practices were agreed upon for developing competencies, 15 principles for effective practice were agreed upon for developing assessments, and 16 principles for effective practice were agreed upon regarding learning resources. Areas of disagreement were also identified, with evidence that variation was due to the unique contexts of higher education programs.ConclusionThis study contributes to CBE by providing an emerging list of effective practices useful in developing CBE programs.
A Method to Generate and Analyze Modified Myristoylated Proteins
Authors: Gao Huanyao , Sun Wei , Song Zhiquan , Yu Yanbao , Wang Li , Chen Xian , Zhang Qisheng 
Published: December 2016

AbstractCovalent lipid modification of proteins is essential to their cellular localizations and functions. Engineered lipid motifs, coupled with bio‐orthogonal chemistry, have been utilized to identify myristoylated or palmitoylated proteins in cells. However, whether modified proteins have similar properties as endogenous ones has not been well investigated mainly due to lack of methods to generate and analyze purified proteins. We have developed a method that utilizes metabolic interference and mass spectrometry to produce and analyze modified, myristoylated small GTPase ADP‐ribosylation factor 1 (Arf1). The capacities of these recombinant proteins to bind liposomes and load and hydrolyze GTP were measured and compared with the unmodified myristoylated Arf1. The ketone‐modified myristoylated Arf1 could be further labeled by fluorophore‐coupled hydrazine and subsequently visualized through fluorescence imaging. This methodology provides an effective model system to characterize lipid‐modified proteins with additional functions before applying them to cellular systems.
Identification of N‐Arylated NH125 Analogues as Rapid Eradicating Agents against MRSA Persister Cells and Potent Biofilm Killers of Gram‐Positive Pathogens
Authors: Abouelhassan Yasmeen , Basak Akash , Yousaf Hussain , Huigens Robert W. 
Published: December 2016

AbstractBacterial biofilms housing dormant persister cells are innately tolerant to antibiotics and disinfectants, yet several membrane‐active agents are known to eradicate tolerant bacterial cells. NH125, a membrane‐active persister killer and starting point for development, led to the identification of two N‐arylated analogues (1 and 2) that displayed improved biofilm eradication potencies compared to the parent compound and rapid persister‐cell‐killing activities in stationary cultures of methicillin‐resistant Staphylococcus aureus (MRSA). We found 1 and 2 to be superior to other membrane‐active agents in biofilm eradication assays, with 1 demonstrating minimum biofilm eradication concentrations (MBEC) of 23.5, 11.7, and 2.35 μm against MRSA, methicillin‐resistant Staphylococcus epidermidis (MRSE), and vancomycin‐resistant Enterococcus faecium (VRE) biofilms, respectively. We tested our panel of membrane‐active agents against MRSA stationary cultures and found 1 to rapidly eradicate MRSA stationary cells by 4 log units (99.99 %) in 30 min. The potent biofilm eradication and rapid persister‐cell‐killing activities exhibited by N‐arylated NH125 analogues could have significant impact in addressing biofilm‐associated problems.
CYP19A1, MIF and ABCA1 genes are targets of the RORα in monocyte and endothelial cells
Authors: Coban Neslihan , Gulec Cagri , Ozsait‐Selcuk Bilge , Erginel‐Unaltuna Nihan 
Published: December 2016

AbstractRORα is a member of nuclear receptor superfamily of transcription factors, which has a vital role in the regulation of various physiological processes. Cholesterol is a known ligand of RORα and is one of the key components that take part in cardiovascular diseases such as atherosclerosis. Therefore, it is possible that RORα might have a role in the development of atherosclerosis. To test this hypothesis, we investigated the presence of novel RORα response elements (ROREs) located in the promoter of CYP19A1, MIF and ABCA1 genes. Briefly, the occupancy of RORα in the promoter regions of these genes was demonstrated in THP‐1 and HUVEC cell lines by ChIP analysis. In order to modulate RORα activity, THP‐1 and HUVEC cells were treated with specific RORα ligands (CPG 52608 and SR1001) and then the expression levels of target genes were analysed. In the next step, we tested whether RORα activity in THP‐1 macrophages was influenced by the presence of simvastatin, a cholesterol lowering drug. We found that in the presence of simvastatin the expression of the investigated target genes were down regulated and that this regulation was partially prevented by CPG 52608 and SR1001. Results of this study suggest that CYP19A1, MIF and ABCA1 are the direct target genes of RORα. In conclusion, it is important to demonstrate that certain genes involved in the development of atherosclerosis could be modulated by an inducible transcription factor. Therefore, these results offer a potential therapeutic approach for the treatment of atherosclerosis.
General Synthetic Protocol for the Synthesis of Ru‐X (X=Rh, Pd, Ag) Heterogeneous Ultrathin Nanowires with a Tunable Composition
Authors: Sun Dalei , Yu Hong , Su Hao , Jin Feng , Liu Jincheng , Li Cheng Chao 
Published: December 2016

AbstractHerein, a wet‐chemical strategy was devised for the preparation of ultrathin Ru‐based (Ru‐Pd, Ru‐Ag, and Ru‐Rh) heterogeneous nanowires without the use of templates and organic solvents. The success of this synthetic strategy relies on the combination of heterogeneous nucleation and oriented attachment processes. In the synthesis, polyvinylpyrrolidone (PVP) and sodium iodide play very important roles in the growth of the ultrathin nanowires. PVP induces the linear attachment of Ru‐based nanostructures, and I− ions effectively tune the reaction kinetics of the reduction of the metal ions through the formation of more stable compounds. The average diameter of the Ru‐based nanowires is only 3 nm, approximately 12 atoms thick. Importantly, the components of the ultrathin nanowires can be tuned easily by changing the types of precursors and concentrations. As a result of the ultrathin structure and heterojunctions, the as‐synthesized Ru‐based ultrathin nanowires exhibit a good catalytic activity in the Suzuki–Miyaura reaction with a low loss of catalytic activity after several reuses.
Three‐Dimensional Hierarchical Porous Nitrogen and Sulfur‐Codoped Graphene Nanosheets for Oxygen Reduction in Both Alkaline and Acidic Media
Authors: Huang Zheng , Zhou Haihui , Yang Wenji , Fu Chaopeng , Chen Liang , Kuang Yafei 
Published: December 2016

AbstractHeteroatom‐doped carbon materials show superior oxygen reduction reaction (ORR) performance and served as alternatives to Pt‐based catalysts for the commercialization of fuel cells. However, these doped carbon materials only show good ORR activity in alkaline medium, they are generally less effective in acidic electrolytes. The appropriate combination of high dopant distribution and engineered morphology of doped carbon materials is essential to realize high ORR performance. Herein, we propose a novel and effective approach to synthesize three‐dimensional hierarchical porous nitrogen and sulfur‐codoped graphene nanosheets (NSG) as ORR catalysts in both alkaline and acid media. Firstly, the self‐assembled pyrrole layer was polymerized on graphene oxide template to form a molecule‐thick polypyrrole (PPy) layer using (NH4)2S2O8 oxidant, resulting in a sandwich‐like S‐containing PPy/GO nanosheets (S–PPy–GO–PPy–S), then the S–PPy–GO–PPy–S was pyrolyzed to generate 3 D hierarchical porous NSG with uniformly distributed high level multiple dopant (9.05 at % of N and 1.65 at % of S). As a result, the NSG exhibits comparable or even better ORR performance in both alkaline and acid media than the noble metal Pt/C catalyst. The achieved high performance is ascribed to the uniformly distributed high content doped elements and three‐dimensional hierarchical porous structure, providing more active sites for ORR.