bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Field Modulation of the Octahedral Framework in Metal Oxide Heterostructures
Authors: Liu Huajun , Dong Yongqi , Xu Dongwei , Karapetrova Evguenia , Lee Sungsik , Stan Liliana , Zapol Peter , Zhou Hua , Fong Dillon D. 
Published: October 2018

AbstractControl over the oxygen octahedral framework is widely recognized as key to the design of functional properties in perovskite oxide heterostructures. Although the oxygen octahedral framework can be manipulated during synthesis, the as‐grown oxygen octahedra generally remain fixed, preventing the development of adaptive behavior in electronic and ionotronic systems. Here, it is demonstrated that the oxygen octahedral framework can be dynamically and reversibly manipulated by an electric field through the coupling with oxygen vacancies. Studying model WO3 heterostructures during ionic liquid gating with a combination of in situ X‐ray scattering and spectroscopy, it is shown that large changes in electronic properties can arise due to the increased flexibility of the octahedral network at high vacancy concentrations. The results describe a generic framework for the construction of dynamic systems and devices with an array of field‐tunable properties.
Ultrastable Supramolecular Self‐Encapsulated Wide‐Bandgap Conjugated Polymers for Large‐Area and Flexible Electroluminescent Devices
Authors: Lin Jinyi , Liu Bin , Yu Mengna , Wang Xuhua , Lin Zongqiong , Zhang Xinwen , Sun Chen , Cabanillas‐Gonzalez Juan , Xie Linghai , Liu Feng , Ou Changjin , Bai Lubing , Han Yamin , Xu Man , Zhu Wensai , Smith Trevor A. , Stavrinou Paul N. , Bradley Donal D. C. , Huang Wei 
Published: October 2018

AbstractControlling chain behavior through smart molecular design provides the potential to develop ultrastable and efficient deep‐blue light‐emitting conjugated polymers (LCPs). Herein, a novel supramolecular self‐encapsulation strategy is proposed to construct a robust ultrastable conjugated polydiarylfluorene (PHDPF‐Cz) via precisely preventing excitons from interchain cross‐transfer/coupling and contamination from external trace H2O/O2. PHDPF‐Cz consists of a mainchain backbone where the diphenyl groups localize at the 9‐position as steric bulk moieties, and carbazole (Cz) units localize at the 4‐position as supramolecular π‐stacked synthon with the dual functionalities of self‐assembly capability and hole‐transport facility. The synergistic effect of the steric bulk groups and π‐stacked carbazoles affords PHDPF‐Cz as an ultrastable property, including spectral, morphological stability, and storage stability. In addition, PHDPF‐Cz spin‐coated gelation films also show thickness‐insensitive deep‐blue emission with respect to the reference polymers, which are suitable to construct solution‐processed large‐scale optoelectronic devices with higher reproducibility. High‐quality and uniform deep‐blue emission is observed in large‐area solution‐processed films. The electroluminescence shows high‐quality deep‐blue intrachain emission with a CIE (0.16, 0.12) and a very narrow full width at half‐maximum of 32 nm. Finally, large‐area and flexible polymer light‐emitting devices with a single‐molecular excitonic behavior are also fabricated. The supramolecular self‐encapsulation design provides an effective strategy to construct ultrastable LCPs for optoelectronic applications.
Uncovering the Conduction Behavior of van der Waals Ambipolar Semiconductors
Authors: Wang Feng , Tu Bin , He Peng , Wang Zhenxing , Yin Lei , Cheng Ruiqing , Wang Junjun , Fang Qiaojun , He Jun 
Published: October 2018

AbstractA long‐standing puzzle about van der Waals semiconductors (vdWS) is regarding the origin(s) of the conduction behavior they exhibit. Of particular interest are those with ambipolar conduction, which may provide an alternative choice for practical applications when considering the difficulties of doping the ultrathin bodies of vdWS. Here, the conduction behavior of ambipolar vdWS is analytically and theoretically studied. Using numerical simulation, it is shown that ambipolar vdWS can be fully captured by a Schottky‐barrier FET model. Based on this, it is found that the widely observed conduction polarity transition while changing the body thickness mainly comes from the tuning of band alignment at the metal/vdWS interfaces. This transition can be suppressed/inversed by introducing an inert hBN layer between the vdWS and the substrate. Through first‐principles calculations, it is demonstrated that metal/vdWS/substrate interactions play a crucial role in tuning the Schottky‐barrier heights, which finally determines the conduction behavior that ambipolar vdWS exhibit.
Freestanding 3D Mesostructures, Functional Devices, and Shape‐Programmable Systems Based on Mechanically Induced Assembly with Shape Memory Polymers
Authors: Wang Xueju , Guo Xiaogang , Ye Jilong , Zheng Ning , Kohli Punit , Choi Dongwhi , Zhang Yi , Xie Zhaoqian , Zhang Qihui , Luan Haiwen , Nan Kewang , Kim Bong Hoon , Xu Yameng , Shan Xiwei , Bai Wubin , Sun Rujie , Wang Zizheng , Jang Hokyung , Zhang Fan , Ma Yinji , Xu Zheng , Feng Xue , Xie Tao , Huang Yonggang , Zhang Yihui , Rogers John A. 
Published: October 2018

AbstractCapabilities for controlled formation of sophisticated 3D micro/nanostructures in advanced materials have foundational implications across a broad range of fields. Recently developed methods use stress release in prestrained elastomeric substrates as a driving force for assembling 3D structures and functional microdevices from 2D precursors. A limitation of this approach is that releasing these structures from their substrate returns them to their original 2D layouts due to the elastic recovery of the constituent materials. Here, a concept in which shape memory polymers serve as a means to achieve freestanding 3D architectures from the same basic approach is introduced, with demonstrated ability to realize lateral dimensions, characteristic feature sizes, and thicknesses as small as ≈500, 10, and 5 µm simultaneously, and the potential to scale to much larger or smaller dimensions. Wireless electronic devices illustrate the capacity to integrate other materials and functional components into these 3D frameworks. Quantitative mechanics modeling and experimental measurements illustrate not only shape fixation but also capabilities that allow for structure recovery and shape programmability, as a form of 4D structural control. These ideas provide opportunities in fields ranging from micro‐electromechanical systems and microrobotics, to smart intravascular stents, tissue scaffolds, and many others.
Controlled Adhesion Anisotropy between Two Rectangular Grooved Surfaces
Authors: Liu Zheyu , Tao Dashuai , Zhou Ming , Lu Hongyu , Meng Yonggang , Tian Yu 
Published: October 2018

AbstractFriction or adhesion anisotropy is a key indicator in surface physics and chemistry. Compared with friction anisotropy, a few studies focus on adhesion anisotropy, which has a profound potential in guiding the application of biomimetic adhesive surfaces. The adhesion anisotropy coefficients (the ratio of maximum adhesion to the minimum one) of the reported biomimetic surfaces are mostly less than 20. In this study, a simple strategy is proposed to achieve a significant adhesion anisotropy between two same rectangular grooved (RG) polymer surfaces. The corresponding adhesion force can be varied by over two orders of magnitude by changing the aligning state, far beyond the previously reported adhesion anisotropy coefficient. As expected, the strongest adhesion appears when the grooves are parallel to each other, while the weakest adhesion exists at a perpendicular crossing contact. The complex alignment between two same micro‐RG surfaces is accurately accomplished by using moiré patterns. Applying a lateral shearing at a matching state can further enhance the adhesion due to the side‐wall friction. This apparent adhesion anisotropy has a great potential to be used in novel flexible dry adhesive grippers or connectors.
Self‐Assembled 3D Hierarchical Porous Hybrid as Platinum‐Like Bifunctional Nonprecious Metal Catalyst toward Oxygen Reduction Reaction and Hydrogen Evolution Reaction
Authors: He Chunyong , Tao Juzhou , Shen Pei Kang 
Published: October 2018

AbstractA class of novel CoNC active nanoparticles anchored on 3D hierarchical porous graphene‐like carbon nanosheets compositions (CoNC@3D HPG) with high porosity, high specific surface area, interconnected pores, and a hierarchical pore structure are synthesized, which are perfect as electrochemical electrode scaffolds, giving rise to efficient and rapid pathways for ion and electron transport, which certainly facilitate the mass transport. This hybrid catalyst possesses outstanding oxygen reduction reaction (ORR) activity through a four‐electron transfer process. Most importantly, the ORR activity of this material is superior to Pt/C catalyst, better stability and fuel (methanol and CO) tolerance than Pt/C catalyst. Besides, the CoNC@3D HPG also exhibits outstanding electrocatalytic performance as an efficient hydrogen evolution reaction catalyst with zero onset overpotential, low overpotential at large current density, small Tafel slope, high exchange current density, and excellent durability. It is worth noting that this outstanding bifunctional catalyst is prepared by a novel resin‐based self‐assembly growth methodology at large‐scale.
Stereospecific Al‐Catalysed TandemC−N/C−SeBond Formation of Isoselenocyanates with Aziridines: Synthesis and DFT Study
Authors: Satheesh Vanaparthi , Srivastava Hemant Kumar , Kumar Sundaravel Vivek , Sengoden Mani , Punniyamurthy Tharmalingam 
Published: October 2018

AbstractAl‐catalyzed stereospecific tandemC−N/C−Sebond formation of chiral aziridines with isoselenocyanates is described with 90–99% ee and 77–91% yields. The mechanistic investigation using the computational study suggests that the reaction involves a concerted pathway (SN2). The selectivity and substrate scope are the important practical features.magnified image
Iridium‐Catalyzed Asymmetric Hydrogenation of N‐Alkyl α‐Aryl Furan‐Containing Imines: an Efficient Route to Unnatural N‐Alkyl Arylalanines and Related Derivatives.
Authors: Mazuela Javier , Antonsson Thomas , Knerr Laurent , Marsden Stephen P. , Munday Rachel H. , Johansson Magnus J. 
Published: October 2018

AbstractHigh throughput experimentation (HTE) has enabled the rapid identification of ligand/precatalyst combinations that facilitate highly enantioselective hydrogenations of prochiral N‐alkyl α‐aryl ketimines containing a furyl moiety. The chiral amines obtained have proven to be modular precursors in the synthesis of unnatural mono N‐alkylated arylalanines and related derivatives.magnified image
In‐Plane Mechanically Gradated 2D Materials: Exploring Graphene/SiC/Silicene Transition via Full Atomistic Simulation
Authors: Zhang Hanming , Cranford Steven W. 
Published: October 2018

AbstractThe emergence of 2D materials has resulted in many platforms with promising applications. One possibility is to combine two (or more) systems in a multilayered structure. However, can such materials transition in‐plane? Here, the potential of graded transition from graphene to silicene, via 2D silicon carbide is explored. The work focuses on mechanical performance of a two‐phase gradated system under uniaxial stress. The percentage of the carbon/silicon in‐plane, to explore the resulting effects on strength and stiffness using full atomistic molecular dynamics (MD) is varied. Carbon atom placement of 0% to 100% in nine increments with random substitution, is tested using both single‐bond and mixed‐bond homogeneous and two‐phase gradated models. Stiffness and strength can be predicted by a simple model accounting for proportional bond distributions. It is demonstrated that the inclusion of nominal amounts of Si–C bonding results in drastic changes in mechanical response when compared to graphene, tolerant to change across a wide range of distributions, suggesting a “weakest link” effect. For the two‐phase gradated systems, stress contour plots correlate with changes in silicon‐to‐carbon ratios. The work demonstrates the feasibility of a new class of 2D in‐plane gradated materials with tunable stiffness, predictable strength, and controlled failure.
Photolytic Reductive Elimination of White Phosphorus from a Mononuclear cyclo‐P4 Transition Metal Complex
Authors: Mandla Kyle A. , Moore Curtis E. , Rheingold Arnold L. , Figueroa Joshua S. 
Published: October 2018

AbstractElemental white phosphorus (P4) is well recognized as a critical precursor to organophosphorus compounds. However, regulatory constraints stemming from the toxic and pyrophoric nature of white phosphorus have significantly limited its accessibility. Herein is described a new approach to white phosphorus storage and release based on a unique example of photolytic reductive elimination of the tetrahedral P4 molecule from a mononuclear cyclo‐P4 molybdenum complex. The latter functions as an air‐stable, chemically‐deactivated source of white phosphorus. The system features efficient photo‐release of white phosphorus using inexpensive violet LED sources. Additionally, high‐yield recapture of unspent white phosphorus by the molybdenum center can be achieved by post‐photolysis heating at convenient temperatures.
The Radical Pathway Based on a Lithium‐Metal‐Compatible High‐Dielectric Electrolyte for Lithium–Sulfur Batteries
Authors: Zhang Ge , Peng Hong‐Jie , Zhao Chen‐Zi , Chen Xiang , Zhao Li‐Da , Li Peng , Huang Jia‐Qi , Zhang Qiang 
Published: October 2018

AbstractHigh‐dielectric solvents were explored for enhancing the sulfur utilization in lithium–sulfur (Li−S) batteries, but their applications have been impeded by low stability at the lithium metal anode. Now a radical‐directed, lithium‐compatible, and strongly polysulfide‐solvating high‐dielectric electrolyte based on tetramethylurea is presented. Over 200 hours of cycling was realized in Li|Li symmetric cells, showing good compatibility of the tetramethylurea‐based electrolyte with lithium metal. The high solubility of short‐chain polysulfides, as well as the presence of active S3.− radicals, enabled pouch cells to deliver a discharge capacity of 1524 mAh g−1 and an energy density of 324 Wh kg−1. This finding suggests an alternative recipe to ether‐based electrolytes for Li−S batteries.
Domino Synthesis of α,β‐Unsaturated γ‐Lactams by Stereoselective Amination of α‐Tertiary Allylic Alcohols
Authors: Xie Jianing , Xue Sijing , Escudero‐Adán Eduardo C. , Kleij Arjan W. 
Published: October 2018

AbstractTertiary allylic alcohols equipped with a carboxyl group can be smoothly aminated under ambient conditions by a conceptually new and stereoselective protocol under palladium catalysis. The in situ formed Z‐configured γ‐amino acid cyclizes to afford an α,β‐unsaturated γ‐lactam, releasing water as the only byproduct. This practical catalytic transformation highlights the use of a carboxyl group acting as an activating and stereodirecting functional group to provide a wide series of pharma‐relevant building blocks. Various control reactions support the crucial role of the carboxyl group in the substrate to mediate these transformations.
Measuring Diffusion Constants of Invisible Protein Conformers by Triple‐Quantum 1H CPMG Relaxation Dispersion
Authors: Yuwen Tairan , Sekhar Ashok , Baldwin Andrew J. , Vallurupalli Pramodh , Kay Lewis E. 
Published: October 2018

AbstractProteins are not locked in a single structure but often interconvert with other conformers that are critical for function. When such conformers are sparsely populated and transiently formed they become invisible to routine biophysical methods, however they can be studied in detail by NMR spin‐relaxation experiments. Few experiments are available in the NMR toolkit, however, for characterizing the hydrodynamic properties of invisible states. Herein we describe a CPMG‐based experiment for measuring translational diffusion constants of invisible states using a pulsed‐field gradient approach that exploits methyl 1H triple‐quantum coherences. An example, involving diffusion of a sparsely populated and hence invisible unfolded protein ensemble is presented, without the need for the addition of denaturants that tend to destroy weak interactions that can be involved in stabilizing residual structure in the unfolded state.
AlkAniline‐Seq: Profiling of m7G and m3C RNA Modifications at Single Nucleotide Resolution
Authors: Marchand Virginie , Ayadi Lilia , Ernst Felix G. M. , Hertler Jasmin , Bourguignon‐Igel Valérie , Galvanin Adeline , Kotter Annika , Helm Mark , Lafontaine Denis L. J. , Motorin Yuri 
Published: October 2018

AbstractRNA modifications play essential roles in gene expression regulation. Only seven out of >150 known RNA modifications are detectable transcriptome‐wide by deep sequencing. Here we describe a new principle of RNAseq library preparation, which relies on a chemistry based positive enrichment of reads in the resulting libraries, and therefore leads to unprecedented signal‐to‐noise ratios. The proposed approach eschews conventional RNA sequencing chemistry and rather exploits the generation of abasic sites and subsequent aniline cleavage. The newly generated 5′‐phosphates are used as unique entry for ligation of an adapter in library preparation. This positive selection, embodied in the AlkAniline‐Seq, enables a deep sequencing‐based technology for the simultaneous detection of 7‐methylguanosine (m7G) and 3‐methylcytidine (m3C) in RNA at single nucleotide resolution. As a proof‐of‐concept, we used AlkAniline‐Seq to comprehensively validate known m7G and m3C sites in bacterial, yeast, and human cytoplasmic and mitochondrial tRNAs and rRNAs, as well as for identifying previously unmapped positions.
Mesoporous Encapsulated Chiral Nanogold for Use in Enantioselective Reactions
Authors: Zhou Ya , Sun Hanjun , Xu Hongcheng , Matysiak Silvina , Ren Jinsong , Qu Xiaogang 
Published: October 2018

AbstractAlthough various nanomaterials have been designed for biocatalysis, few of them can accelerate chemical reactions with high selectivity and stereocontrol, which remains them from being perfect alternatives to nature enzymes. Herein, inspired by the natural enzymes, an enantioselective nanomaterial has been constructed, with gold nanoparticles (AuNPs) as active centers, chiral cysteine (Cys) as selectors for chiral recognition, and expanded mesoporous silica (EMSN) as a skeleton of the artificial enzyme. In the oxidation of chiral 3,4‐dihydroxy‐phenylalanine (DOPA), the nanozyme with d‐Cys shows preference to l‐DOPA while the artificial enzyme with l‐Cys shows preference to d‐DOPA. Subsequent calculation of apparent steady‐state kinetic parameters and activation energies together with molecular dynamics (MD) simulations showed that the different affinity precipitated by hydrogen bonding formation between chiral Cys and DOPA is the origin of chiral selectivity.
Digital Control of Multistep Hydrothermal Synthesis by Using 3D Printed Reactionware for the Synthesis of Metal–Organic Frameworks
Authors: Lin Chang‐Gen , Zhou Wei , Xiong Xue‐Ting , Xuan Weimin , Kitson Philip J. , Long De‐Liang , Chen Wei , Song Yu‐Fei , Cronin Leroy 
Published: October 2018

AbstractHydrothermal‐synthesis‐based reactions are normally single step owing to the difficulty of manipulating reaction mixtures at high temperatures and pressures. Herein we demonstrate a simple, cheap, and modular approach to the design reactors consisting of partitioned chambers, to achieve multi‐step synthesis under hydrothermal conditions, in digitally defined reactionware produced by 3D printing. This approach increases the number of steps that can be performed sequentially and allows an increase in the options available for the control of hydrothermal reactions. The synthetic outcomes of the multi‐stage reactions can be explored by varying reaction compositions, number of reagents, reaction steps, and reaction times, and these can be tagged to the digital blueprint. To demonstrate the potential of this approach a series of polyoxometalate (POM)‐containing metal–organic frameworks (MOFs) unavailable by “one‐pot” methods were prepared as well as a set of new MOFs.
Synthesis and Characterization of Novel Polyol Esters of Undecylenic Acid As Ecofriendly Lubricants
Authors: Cavalcante Igor Marques , Rocha Natália Rodrigues de Castro , de Brito Débora Hellen Almeida , Schuller Ana Paula Dantas , Câmara Neto João Francisco , de Morais Selene Maia , de Luna Francisco Murilo Tavares , Schanz Maria Telma Gomes Freire , Maier Martin E. , Ricardo Nágila Maria Pontes Silva 
Published: October 2018

AbstractThree novel esters of undecylenic acid (UA) were synthesized using the following polyols: linear diglycerol (DG), pentaerythritol monomethylether (PEME), and trimethyloltoluene (TMT). They were characterized through density, viscosity, thermo‐oxidative stability, melting point (m.p.), miscibility with mineral oils, and toxicity to evaluate their potential as ecofriendly lubricants. Trimethylolpropane (TMP) triundecylenate was also synthesized and characterized as a reference ester. Esters’ densities were in the range 0.93–0.97 g cm−3. The PEME ester showed a kinematic viscosity of 25.2 cSt at 40°C, only slightly higher than that of TMP ester (24.7 cSt), both of them near the ISO VG 22 class, while DG and TMT esters were near the ISO VG 32 class, with viscosities of 28.3 and 37.1 cSt, respectively. PEME and TMT esters were similar in thermo‐oxidative stability and more stable than their corresponding oleate esters. The m.p. of TMT ester was remarkedly low (−54°C), showing its potential for very cold temperature applications. TMT ester was found to be nontoxic against Artemia salina (LC50 > 1000 μg mL−1), an initial indication of nontoxicity of UA esters in aquatic media. The synthesized esters showed potential to be applied as ecofriendly lubricants.
Introducing nonlinear dynamics to chemical and biochemical engineering graduate students using MATHEMATICA©
Authors: Binous Housam , Bellagi Ahmed 
Published: October 2018

AbstractIn the present paper, we present the solution of four problems drawn from the chemical and biochemical engineering field of study. These problems illustrate various important aspects of nonlinear dynamics such as limit cycles, quasi‐periodic and chaotic behaviors, time series and phase portraits, power spectra, the time‐delay reconstruction diagrams, Hopf bifurcation, bifurcation diagrams, steady state multiplicity… Among a large number of examples, we have selected the following case studies because they illustrate the basic nonlinear dynamics concepts listed previously: (i) The glycolytic oscillator model, first suggested by Sel'kov in 1968 in order to elucidate the mechanism that living cells use to obtain energy from sugar breakdown; (ii) The Oregonator model derived by Field, Körös, and Noyes in the early 1970s, which elucidates the famous oscillatory behavior observed in the Belousov–Zhabotinsky reaction; (iii) The steady state multiplicity in a biochemical reactor for both the Monod and substrate inhibition kinetics; and (iv) The three‐variable autocatalator, first proposed by Peng, Scott, and Showalter in 1990. Finally, we conclude this paper by sharing our experience teaching this subject to graduate students at King Fahd University of Petroleum & Minerals (KFUPM).