bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Artificial Heme Enzyme for Cyclopropanation Reactions
Authors: Villarino Lara , Splan Kathryn E. , Reddem Eswar , Alonso‐Cotchico Lur , Gutiérrez de Souza Cora , Lledós Agustí , Maréchal Jean‐Didier , Thunnissen Andy‐Mark W. H. , Roelfes Gerard 
Published: May 2018

AbstractAn artificial heme enzyme was created through self‐assembly from hemin and the lactococcal multidrug resistance regulator (LmrR). The crystal structure shows the heme bound inside the hydrophobic pore of the protein, where it appears inaccessible for substrates. However, good catalytic activity and moderate enantioselectivity was observed in an abiological cyclopropanation reaction. We propose that the dynamic nature of the structure of the LmrR protein is key to the observed activity. This was supported by molecular dynamics simulations, which showed transient formation of opened conformations that allow the binding of substrates and the formation of pre‐catalytic structures.
Perfluoroalcohols: The Preparation and Crystal Structures of Heptafluorocyclobutanol and Hexafluorocyclobutane‐1,1‐diol
Authors: Baxter Amanda F. , Schaab Jonas , Christe Karl O. , Haiges Ralf 
Published: May 2018

AbstractThe first X‐ray crystal structure of an α‐fluoroalcohol is reported. Heptafluorocyclobutanol was obtained in quantitative yield from hexafluorocyclobutanone by HF addition in anhydrous hydrogen fluoride. The compound was characterized by its X‐ray single crystal structure. Heptafluorocyclobutanol readily undergoes hydrolysis to hexafluorocyclobutane‐1,1‐diol, which was also structurally characterized by X‐ray diffraction.
Enantiodivergent Synthesis of Allenes by Point‐to‐Axial Chirality Transfer
Authors: Armstrong Roly J. , Nandakumar Meganathan , Dias Rafael M. P. , Noble Adam , Myers Eddie L. , Aggarwal Varinder K. 
Published: May 2018

AbstractAn enantiodivergent method for the synthesis of multiply substituted allenes is described. Highly enantioenriched, point‐chiral boronic esters were synthesized by homologation of α‐seleno alkenyl boronic esters with lithiated carbamates and eliminated to form axially chiral allene products. By employing either oxidative or alkylative conditions, both syn and anti elimination could be achieved with complete stereospecificity. The process enables the synthesis of either M or P allenes from a single isomer of a point‐chiral precursor and can be employed for the enantioselective assembly of di‐, tri‐, and tetrasubstituted allenes.
Properties of Oleogels Formed With High‐Stearic Soybean Oils and Sunflower Wax
Authors: Hwang Hong‐Sik , Gillman Jason D. , Winkler‐Moser Jill K. , Kim Sanghoon , Singh Mukti , Byars Jeffrey A. , Evangelista Roque L. 
Published: May 2018

AbstractIn an effort to develop alternatives for harmful trans fats produced by partial hydrogenation of vegetable oils, oleogels of high‐stearic soybean (A6 and MM106) oils were prepared with sunflower wax (SW) as the oleogelator. Oleogels of high‐stearic oils did not have greater firmness when compared to regular soybean oil (SBO) at room temperature. However, the firmness of high‐stearic oil oleogels at 4 °C sharply increased due to the high content of stearic acid. High‐stearic acid SBO had more polar compounds than the regular SBO. Polar compounds in oil inversely affected the firmness of oleogels. Differential scanning calorimetry showed that wax crystals facilitated nucleation of solid fats of high‐stearic oils during cooling. Polar compounds did not affect the melting and crystallization behavior of wax. Solid fat content (SFC) showed that polar compounds in oil and wax interfered with crystallization of solid fats. Linear viscoelastic properties of 7% SW oleogels of three oils reflected well the SFC values while they did not correlate well with the firmness of oleogels. Phase‐contrast microscopy showed that the wax crystal morphology was slightly influenced by solid fats in the high‐steric SBO, A6.
Capitalist maturity and South Korea's post‐development conundrum
Authors: D'Costa Anthony P. 
Published: May 2018

AbstractSouth Korea's post World War II economic development trajectory is well known. From an impoverished warn‐torn nation, the country has progressed on all fronts. However, the objective is to focus on the “post‐development” question, namely, what does a country do after it becomes prosperous. To put it another way, what are some of the emergent challenges that successful development poses for Korea, and how might it tackle them. I use the concept of capitalist maturity to denote Korea's current state of prosperity and examine some of the economic, social, and political consequences. Some of these post‐development conundrums I argue have resulted from the transformation of Korea's state–business development partnership to a business–state political partnership in the context of a democratizing Korea. This paper examines the challenges and some of the policy options to address them, including the rebalancing of the state–business relationship.
Insight into How Telomeric G‐Quadruplexes Enhance the Peroxidase Activity of Cellular Hemin
Authors: Ai Tingting , Yang Qiufang , Lv You , Huang Yuqin , Li Yuzhi , Geng Jia , Xiao Dan , Zhou Cuisong 
Published: May 2018

AbstractThe toxic oxidative damage of G‐quadruplexes (G4), linked to neurodegenerative diseases, may arise from their ability to bind and oxidatively activate cellular hemin. However, there have been no precise studies on how telomeric G4 enhances the low intrinsic peroxidase activity of hemin. Herein, a label‐free and nanopore‐based strategy was developed to explore the enhancement mechanism of peroxidase activity of hemin induced by telomeric G4 (d(TTAGGG)n). The nanopore‐based strategy demonstrated that there were simultaneously two different binding modes of telomere G4 to hemin. At the single‐molecule level, it was found that the hybrid structural telomeric G4 directly binds to hemin (the affinity constant (Ka)≈106 m−1) to form a tight complex, and some of them underwent a topological change to a parallel structure with an enhancement of Ka to approximately 107 m−1. Through detailed analysis of the topology and peroxidase activity and molecular modeling investigations, the parallel telomere G4/hemin DNAzyme structure was proven to be preferable for high peroxidase activity. Upon strong π–π stacking, the parallel structural telomere G4 supplied a key axial ligand to the hemin iron, which accelerated the intermediate compound formation with H2O2 in the catalytic cycle. Our studies developed a label‐free and single‐molecule strategy to fundamentally understand the catalytic activity and mechanism of telomeric DNAzyme, which provides some support for utilizing the toxic, oxidative‐damage property in cellular oxidative disease and anticancer therapeutics.
Pd‐Catalyzed Decarbonylative C−H Coupling of Azoles and Aromatic Esters
Authors: Matsushita Kaoru , Takise Ryosuke , Hisada Tomoya , Suzuki Shin , Isshiki Ryota , Itami Kenichiro , Muto Kei , Yamaguchi Junichiro 
Published: May 2018

AbstractA decarbonylative C−H coupling of azoles and aromatic esters by palladium catalysis is described. Our previously reported Ni‐catalyzed C−H coupling of azoles and aromatic esters has a significant drawback regarding the substrate scope. Herein, we employ palladium catalysis instead of nickel, resulting in a broader substrate scope in terms of azoles and aromatic esters.
How to calculate thermostability of enzymes using a simple approach
Authors: Saqib Abdul A. N. , Siddiqui Khawar S. 
Published: May 2018

AbstractDetermination of thermostability of enzymes is of prime importance for their successful industrial applications and, yet, the published data has often been incompletely analyzed to assess the suitability of enzymes. It is possible to determine meaningful thermostability parameters from the routinely acquired data through a straightforward method that is not only more informative but also provides a means to compare thermostability of enzymes from different sources. Here, we describe a simple, effective, and economical way to determine enzyme thermostability. In our opinion, including this method in Biochemistry and Molecular Biology curricula will encourage students to include thermostability analysis in their future work, leading to a more meaningful approach to evaluate and compare enzymes. Furthermore, as the method requires minimum specialized equipment, the analysis will be particularly suitable for labs that cannot afford expensive setup. © 2018 by The International Union of Biochemistry and Molecular Biology, 46:398–402, 2018.
Analyzing the effects of adapted flipped classroom approach on computer programming success, attitude toward programming, and programming self‐efficacy
Authors: Özyurt Hacer , Özyurt Özcan 
Published: May 2018

AbstractThis study analyzes the effects of the use of adapted flipped classroom approach on the programming success, attitudes, and self‐efficacy of the students in learning programming. The study was conducted in the 2016–2017 fall semester with freshman students in Introduction to Programming and Algorithm course in the Software Engineering Department of a university in Turkey. The sample of the study consists of 46 students taking this course for the first time. The quasi‐experimental research method was used in the study. One group pretest–posttest design was employed, and quantitative data were obtained from the students. The scale of attitude toward computer programming, computer programming self‐efficacy scale, computer programming success test, and practice control chart were used as data collection tools. The study results show that the use of this approach in programming learning has a positive effect on the students’ programming success and programming self‐efficacy while it does not affect their attitudes toward programming. Additionally, it is concluded that there is a highly positive relationship between the numbers of students’ fulfilling the programming tasks and their programming success. Another conclusion of the study is that there is a positive relationship at a medium level between the numbers of students’ fulfilling the programming tasks and programming self‐efficacy and their attitudes toward programming. Considering the study results as a whole, it is seen that flipped classroom approach can be adapted to teach programming.
Impact of paranasal sinus invasion on advanced nasopharyngeal carcinoma treated with intensity‐modulated radiation therapy: the validity of advanced T stage of AJCC/UICC eighth edition staging system
Authors: Wang Ying , Zhao Jie , Zhao Yajie , Yang Zhen , Lei Mingjun , Li Zhanzhan , Wei Rui , Chen Dengming , He Yuxiang , Shen Liangfang 
Published: May 2018

AbstractThe aim of this study was to clarify the prognostic role of paranasal sinus invasion in advanced NPC patients. Data of patients (n = 295) with advanced NPC (T3/T4N0‐3 M0) treated with intensity‐modulated radiation therapy were retrospectively analyzed. Staging was according to the AJCC/UICC eighth edition staging system. Overall survival (OS), local recurrence‐free survival (LRFS), distant metastasis‐free survival (DMFS), and disease‐free survival (DFS) were calculated, and differences were compared between patients with and without paranasal sinus invasion. Multivariate analysis was used to identify the independent predictors of different survival parameters. Paranasal sinus invasion was present in 126 of 295 (42.7%) patients. Sphenoid, ethmoid, maxillary, and frontal sinus involvements were present in 123 of 295 (41.7%), 95 of 295 (32.2%), 45 of 295 (15.3%), and 0 of 295 (0%), respectively. All survival parameters were significantly better in patients without paranasal sinus invasion. When paranasal sinus invasion was reclassified as T4 instead of T3, all survival rates, other than LRFS (P = 0.156), were significantly better in the new T3 patients, and differences in all survival parameters remained nonsignificant between T3 with paranasal sinus invasion and T4 without paranasal sinus invasion patients (all P > 0.05). In multivariate analysis, paranasal sinus invasion was found to be an independent negative prognostic factor for OS, DFS, and DMFS (P = 0.016, P = 0.004, and P = 0.006, respectively), but not for LRFS (P = 0.068). Paranasal sinus invasion has prognostic value in advanced NPC. It may be reasonable to classify paranasal sinus invasion as T4 stage.
Emotional facial expression transfer from a single image via generative adversarial nets
Authors: Qiao Fengchun , Yao Naiming , Jiao Zirui , Li Zhihao , Chen Hui , Wang Hongan 
Published: May 2018

AbstractFacial expression transfer from a single image is a challenging task and has drawn sustained attention in the fields of computer vision and computer graphics. Recently, generative adversarial nets (GANs) have provided a new approach to facial expression transfer from a single image toward target facial expressions. However, it is still difficult to obtain a sequence of smoothly changed facial expressions. We present a novel GAN‐based method for generating emotional facial expression animations given a single image and several facial landmarks for the in‐between stages. In particular, landmarks of other subjects are incorporated into a GAN model to control the generated facial expression from a latent space. With the trained model, high‐quality face images and a smoothly changed facial expression sequence can be effectively obtained, which are showed qualitatively and quantitatively in our experiments on the Multi‐PIE and CK+ data sets.
Sketch‐based shape‐preserving tree animations
Authors: Wang Yutong , Wang Luyuan , Deng Zhigang , Jin Xiaogang 
Published: May 2018

AbstractWe present a novel and intuitive sketch‐based tree animation technique, targeting on generating a new type of special effect of smoothly transforming leafy trees into morphologically different new shapes. Both topological consistencies of branches and meaningful in‐between crown shapes are preserved during the transformation. Specifically, it takes a leafy tree and a user's sketch describing the silhouette of the desired crown shape under a certain viewpoint as the input. Based on a self‐adaptive multiscale cage tree representation, branches are locally transformed through a series of topology‐aware deformations, and the resulting tree conforms to the user‐designed shape, demonstrating better aesthetics compared to global single‐cage‐based methods. By interpolating the transformations, we are able to create visually pleasing shape‐preserving animations of trees transforming between two crown shapes. Our proposed framework also provides an efficient way to interactively edit leafy trees toward desired shapes, demonstrating its potential to leverage existing tree modeling frameworks by providing flexible and intuitive tree editing operations.
Distributed coordination with connectivity maintenance for nonholonomic robots
Authors: Huang Wanrong , Wang Yanzhen , Yi Xiaodong , Yang Xue‐Jun 
Published: May 2018

AbstractMultirobot systems have been studied extensively in the recent years. Maintaining connectivity has significant impacts on the stability and convergence of the multirobot systems. In this work, we design a three‐layer framework for multirobot coordination. Furthermore, a novel distributed algorithm is proposed to achieve the navigation objective while satisfying connectivity maintenance and collision avoidance constraints. The algorithm is a hybrid of an rapidly exploring random tree‐based planner and an extended distributed navigation function‐based controller. The coordination framework and the distributed algorithm are demonstrated to be effective through a series of illustrative simulations. They outperform the current state‐of‐the‐art method in terms of efficiency and applicability.
Example‐based synthesis for sound of ocean waves caused by bubble dynamics
Authors: Wang Kai , Liu Shiguang 
Published: May 2018

AbstractWe present an automatic approach for the semantic modeling of indoor scenes based on a single photograph, instead of relying on depth sensors. Without using handcrafted features, we guide indoor scene modeling with feature maps extracted by fully convolutional networks. Three parallel fully convolutional networks are adopted to generate object instance masks, a depth map, and an edge map of the room layout. Based on these high‐level features, support relationships between indoor objects can be efficiently inferred in a data‐driven manner. Constrained by the support context, a global‐to‐local model matching strategy is followed to retrieve the whole indoor scene. We demonstrate that the proposed method can efficiently retrieve indoor objects including situations where the objects are badly occluded. This approach enables efficient semantic‐based scene editing.
Sawtooth cycle revisited
Authors: Tsuruga Junki , Iwasaki Kei 
Published: May 2018

AbstractSolving the pressure Poisson equation dominates a large portion of computational time for incompressible fluid flow simulations. To solve the pressure Poisson equation efficiently, geometric multigrid methods are used directly or used as the preconditioner for the conjugate gradient (CG) method. Conventionally, the V‐cycle multigrid method is widely employed, and little attention has been paid to other cycles. In this paper, we introduce the sawtooth cycle multigrid method and its simple extension called N‐cycle, which provides better convergence in equal time comparison with the V‐cycle as a direct solver of the pressure Poisson equation. We also apply the N‐cycle to the preconditioner of the CG method and show that the N‐cycle multigrid CG method can provide better convergence than the V‐cycle multigrid CG method.
Insights into the Sorption Mechanisms of Cr(III) by Chemically Modified Pine Bark
Authors: Arim Aline L. , Quina Margarida J. , Gando-Ferreira Licínio M. 
Published: May 2018

AbstractThe mechanisms of Cr(III) sorption by pine bark treated chemically (MPB) with NaOH were investigated. The removal of Cr(III) was found to be strongly dependent on the initial pH. Thus, a model was developed for describing the adsorption as a function of this variable. The removal efficiencies as a function of the adsorbent dosage for different pH values were predicted. The equilibrium data were well fitted by the modified Langmuir isotherm. Ion exchange at equilibrium suggested chromium uptake and Ca2+ release occurs approximately according to the stoichiometry of the equilibrium reactions. Cr(III) desorption from MPB with chelating agents was not very effective while high efficiencies were achieved with HNO3 solutions.
Cu3P/CuO Core‐Shell Nanorod Arrays as High‐Performance Electrocatalysts for Water Oxidation
Authors: Du Jian , Li Fei , Wang Yong , Zhu Yong , Sun Licheng 
Published: May 2018

AbstractEarth‐abundant transition‐metal‐based oxides are potential candidates to replace the state‐of‐the‐art noble‐metal‐based oxygen evolution catalysts (OECs) such as IrO2 and RuO2. Despite the low cost and large abundance, copper‐based OER catalysts have been less frequently studied, mainly owing to the low electrical conductivity of copper oxides that results in large overpotential and sluggish kinetics for oxygen evolution. We report here the in situ fabrication of semi‐metallic Cu3P nanorod arrays on commercial copper foam via a template approach; the resulting self‐supported core‐shell Cu−Cu3P/CuO electrode has the merits of high electrical conductivity, large active area, and short diffusion paths for electrolyte and evolved oxygen, exhibiting a low overpotential of 315 mV and high durability over 50 h at a current density of 10 mA cm−2 for OER in 1.0 M KOH. The remarkable OER performance reported here is not only superior to that of analogous Cu−CuO foam electrode, but also outperforms those of copper‐based OER electrocatalysts in the literature.
Searching for Models Exhibiting High Circularly Polarized Luminescence: Electroactive Inherently Chiral Oligothiophenes
Authors: Benincori Tiziana , Appoloni Giulio , Mussini Patricia Romana , Arnaboldi Serena , Cirilli Roberto , Quartapelle Procopio Elsa , Panigati Monica , Abbate Sergio , Mazzeo Giuseppe , Longhi Giovanna 
Published: May 2018

AbstractTwo new inherently chiral oligothiophenes characterized by the atropisomeric 3,3′‐bithianaphtene scaffold functionalized with fused ring bithiophene derivatives, namely 4H‐cyclopenta[2,1‐b3:4b′]dithiophene (CPDT) and dithieno[3,3‐b:2′,3′‐d]pyrrole (DTP), were synthesized. The racemates were fully characterized and resolved into antipodes by enantioselective HPLC. The enantiomers were analyzed through different chiroptical techniques: electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) were employed to attribute the absolute configuration (AC). Comparison of experimental and calculated VCD spectra confirmed the DFT calculated conformational characteristics. The compound functionalized with two CPDT units was oxidized with FeCl3, and ECD and CPL of the resulting material were measured. Circularly polarized luminescence (CPL) was measured to verify if inherently chiral oligothiophenes could be promising systems for chiral photonics applications.
A Theoretical Outlook on the Stereoselectivity Origins of Isoselective Zirconocene Propylene Polymerization Catalysts
Authors: Castro Ludovic , Therukauff Gabriel , Vantomme Aurelien , Welle Alexandre , Haspeslagh Luc , Brusson Jean‐Michel , Maron Laurent , Carpentier Jean‐François , Kirillov Evgueni 
Published: May 2018

AbstractThe first three insertion steps of propylene for isoselective metallocenes from the one‐carbon‐bridged cyclopentadienyl–fluorenyl {Cp/Flu} and silicon‐bridged ansa‐bis(indenyl) {SBI} families were computed by using a theoretical method implementing the B3PW91 functional in combination with solvent corrections incorporated with the Solvation Model based on Density (SMD) continuum model. For C1‐symmetric {Cp/Flu}‐type metallocenes, two mechanisms of stereocontrol were validated theoretically: more facile and more stereoselective chain “stationary” insertion (or site epimerization backskip) and less stereoselective alternating mechanisms. For the C2‐symmetric {SBI}‐type system, the computation results were in complete agreement with the sole operating chain migratory insertion mechanism. The thermochemical data obtained through the study were used to predict microstructures of polypropylenes by using three‐parameter and one‐parameter statistical models for the two metallocene systems, respectively. The calculated meso/rac pentad distributions were found to be in good agreement with those determined experimentally for isotactic polypropylene samples obtained at different polymerization temperatures.
Late‐Stage Functionalization of Arylacetic Acids by Photoredox‐Catalyzed Decarboxylative Carbon–Heteroatom Bond Formation
Authors: Sakakibara Yota , Ito Eri , Fukushima Tomohiro , Murakami Kei , Itami Kenichiro 
Published: May 2018

AbstractThe rapid transformation of pharmaceuticals and agrochemicals enables access to unexplored chemical space and thus has accelerated the discovery of novel bioactive molecules. Because arylacetic acids are regarded as key structures in bioactive compounds, new transformations of these structures could contribute to drug/agrochemical discovery and chemical biology. This work reports carbon–nitrogen and carbon–oxygen bond formation through the photoredox‐catalyzed decarboxylation of arylacetic acids. The reaction shows good functional group compatibility without pre‐activation of the nitrogen‐ or oxygen‐based coupling partners. Under similar reaction conditions, carbon–chlorine bond formation was also feasible. This efficient derivatization of arylacetic acids makes it possible to synthesize pharmaceutical analogues and bioconjugates of pharmaceuticals and natural products.