bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Controlling 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

A 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

Capabilities 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

Friction 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

A 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

Al‐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.

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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

High 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.

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In‐Plane Mechanically Gradated 2D Materials: Exploring Graphene/SiC/Silicene Transition via Full Atomistic Simulation
Authors: Zhang Hanming , Cranford Steven W.
Published: October 2018

The 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

Elemental 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

High‐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

Tertiary 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

Proteins 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

RNA 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

Although 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

Hydrothermal‐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

Three 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.
Important Considerations for Estimating Odor Threshold Concentrations of Contaminants Found in Water Supplies
Authors: Burlingame Gary A. , Doty Richard L.
Published: October 2018

Natural and man‐made chemicals affect the odor characteristics of drinking water, creating the need to set guidelines for treatment, consumer communication, monitoring, and other considerations. Limits can be based on estimates of odor detection or recognition threshold concentrations by humans. Informed guidance, however, is needed to use threshold testing to identify the levels of odor‐causing chemicals humans can detect. In this article, we touch on this issue, discuss challenges associated with human threshold measurement, and provide examples of how procedures can be made more reliable and less dependent on large numbers of subjects and trials. For example, the single ascending method of limits, a once‐through procedure recommended by ASTM International, can be extended to become a staircase procedure that repeatedly samples the perithreshold region with relatively few trials. Multiple data analyses can be used to determine individual and group thresholds, thereby increasing confidence in the selection of odor threshold concentrations for setting guidelines and standards. Clearly, further research and additional guidance are needed to address how to best measure the sensitivity of humans to odor‐causing chemicals in water.
Mitigating Soil Phosphorus Release Using Liquid Water Treatment Residuals
Authors: Reavis Megan A. , Haggard Brian E.
Published: October 2018

Water treatment residuals (WTRs) have been land‐applied at 20% solids to reduce phosphorus (P) release, but liquid WTRs (2% solids) may be more effective. Our objectives were to show the variability of phosphorus release within a field treated with solid WTRs, determine an optimal application rate for liquid WTRs, and evaluate the long‐term effectiveness of that rate. Six liquid WTR treatment rates (220–4,400 kg/ha) were applied in triplicate to soil cores at varying soil test phosphorus (STP) levels and then flooded. Soluble reactive phosphorus was measured in overlying water, release rates were calculated, and the soil was analyzed for Mehlich‐III and water extractable phosphorus. Release rates were highly variable (2–14 mg/m2/h) within a WTR‐treated field. A small application rate (440 kg/ha) was sufficient to control release at an STP level <100, but greater or repeated application may be necessary for long‐term control.
Distortions From a Simplified Approach to Fatigue Analysis in PVC Pipes
Authors: Malekpour Ahmad , Karney Bryan , McPherson David
Published: October 2018

This work examines the extent to which simplifications suggested for fatigue analysis of polyvinyl chloride (PVC) pipes can cause distortion in system evaluation. To this end, fatigue analysis is performed on a hypothetical pipe system using two independent approaches: first, using a recommended method that calculates the fatigue parameters through thorough transient modeling and, second, through a highly simplified but widely used approach arising from direct application of the Joukowsky equation (through Plastics Pipe Institute's program Pipeline Analysis & Calculation Environment). The results show that the simplified approach significantly overestimates the transient loading and tends to devalue the expected fatigue resistance of PVC pipe. This devaluation arises from the fact that the Joukowsky approach, along with several other assumptions, is too conservative and simplified for fatigue analysis. This study concludes that for the PVC pipe systems exposed to significant pressure cycles, fatigue analysis is a required design check, but only a thorough and thoughtful consideration of transient loading can provide accurate and meaningful results.
Introducing nonlinear dynamics to chemical and biochemical engineering graduate students using MATHEMATICA©
Authors: Binous Housam , Bellagi Ahmed
Published: October 2018

In 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).
Computer‐assisted learning of electromagnetics through MATLAB programming of electromagnetic fields in the creativity thread of an integrated approach to electrical engineering education
Authors: Notaroš Branislav M. , McCullough Ryan , Manić Sanja B. , Maciejewski Anthony A.
Published: October 2018

This paper discusses an integrated approach to electrical‐engineering education that incorporates computer‐assisted MATLAB‐based instruction and learning into the junior‐level electromagnetics course and newly created learning studio modules (LSMs). In this model, creativity class sessions are followed by two comprehensive and rather challenging multi‐week homework assignments of MATLAB problems and projects in electromagnetic fields. This is enabled by a unique and extremely comprehensive collection of MATLAB computer exercises and projects, reinforcing all important theoretical concepts, methodologies, and problem‐solving techniques in electromagnetic fields and waves, developed by one of the faculty team members. These tutorials, exercises, and codes constitute a modern tool for learning electromagnetics via computer‐mediated exploration and inquiry, exploiting the technological and pedagogical power of MATLAB software as a general learning technology. The novel approach introduces students to MATLAB programming of electromagnetic fields, as opposed to just passive demonstrations of MATLAB's tools and capabilities for computation and visualization of fields. MATLAB programming tutorials and assignments are designed to deepen student engagement and accommodate different learning styles so students can learn more effectively. In addition to improving students’ understanding and command of MATLAB use and programming within the electromagnetics context and beyond, these exercises increase their motivation to learn and appreciation of the practical relevance of the material, and equip them with the tools and skills to excel in other courses and projects. The results of this project were qualitatively analyzed through feedback surveys given to the students at the end of each MATLAB assignment. The Electromagnetics Concept Inventory was also used.
Catalytic Gas‐Phase Cyclization of Glycolate Esters: A Novel Route Toward Glycolide‐Based Bioplastics
Authors: De Clercq Rik , Makshina Ekaterina , Sels Bert F. , Dusselier Michiel
Published: October 2018

A catalytic process to produce glycolide, the cyclic dimer of glycolic acid (GA), is proposed. Glycolide is the key building block of the biodegradable plastic polyglycolic acid. Instead of the current industrial two‐step route, which involves the polycondensation of GA and a subsequent backbiting reaction, a new route based on the gas‐phase transesterification of methyl glycolate (MGA) over a fixed catalyst bed is presented. With specific supported TiO2 catalysts, a high glycolide selectivity of 75–78 % can be achieved at the thermodynamically‐limited equilibrium conversion of MGA (54 % at 300 °C, 5.6 vol% MGA, 1 atm). The absence of solvent and the continuous nature of the process should allow for easy product separation and recycling of unconverted esters, while the few side‐products, i. e. linear alkyl glycolate dimers and trimers seem recoverable via methanolysis. The reaction is compared to the cyclization of other α‐hydroxy esters, such as methyl lactate to lactide, over the same catalysts, in terms of kinetics and thermodynamics. The absence of a methyl substitution on the α‐carbon seems to lead to faster cyclization kinetics of MGA when compared to methyl lactate or the double‐substituted methyl‐2‐hydroxy‐isobutyrate. Contrarily, glycolide production is less favored thermodynamically compared to lactide. The absence of glycolide decomposition at temperatures up to 300 °C however allows to increase equilibrium conversion by taking the endergonic reaction to higher temperatures.
Engineering Nanoceria for Enhanced Peroxidase Mimics: A Solid Solution Strategy
Authors: Guo Wenjing , Zhang Mian , Lou Zhangping , Zhou Min , Wang Peng , Wei Hui
Published: October 2018

Nanoceria has been developed as a biocompatible and robust enzyme mimic (called ceria nanozyme) and applied in bioanalysis and therapeutics. However, its catalytic activity such as peroxidase mimic is still moderate, which in turn has limited its promising applications. To tackle this issue, herein we reported an effective strategy to modulate the peroxidase mimicking activity of nanoceria by doping transition metals. We discovered that doping of the first row of transition metals (i. e., Mn, Fe, Co, Ni, and Cu) modulated the activity of nanoceria and with the same doping ratio the activities followed the below order: Mn1Ce10>Co1Ce10>Fe1Ce10>Cu1Ce10>CeO2>Ni1Ce10. By further varying the Mn/Ce ratio, Mn1Ce5 with the highest peroxidase mimicking activity was obtained (13‐fold higher compared with the pristine CeO2). Meanwhile we found that the homogenous doping of Mn into the nanoceria matrix without phase segregation ensured the formation of Mn1Ce5 solid solution. From our experiments and discussion, we concluded that the surface oxygen (Oβ) and the synergistic effect between Ce and Mn played key roles in the enhancement of Mn1Ce5 peroxidase mimicking activity. This study not only demonstrates that Mn‐doped nanoceria exhibits higher active peroxidase mimics but also provides a promising strategy to modulate the catalytic activity of nanozymes.
Electrochemical Oxidation of the Phenolic Benzotriazoles UV‐234 and UV‐327 in Organic Solvents
Authors: Chan Ya Yun , Webster Richard D.
Published: October 2018

The electrochemical behavior of selected phenolic benzotriazoles (BZTs), namely 2‐(2H‐benzotriazol‐2‐yl)‐4,6‐bis(1‐methyl‐1‐phenylethyl)phenol and 2,4‐di‐tert‐butyl‐6‐(5‐chlorobenzotriazol‐2‐yl)phenol (commercial names UV234 and UV327, respectively) were examined with cyclic voltammetry (CV) and controlled potential electrolysis (CPE) in acetonitrile and dichloromethane solutions. CV indicated that both phenolic BZTs undergo a chemically irreversible oxidation process at approximately Ep°x=+1.0 V vs. Fc/Fc+ (where Ep°x is the anodic peak potential and Fc=ferrocene) to form compounds that cannot be electrochemically converted back to the starting material on the voltammetric timescale. In basic conditions, cyclic voltammetry experiments indicated that the corresponding phenolates (prepared by reacting the phenols with equiv. mols of n‐Bu4NOH) were oxidized at Ep°x∼−0.2 V vs. Fc/Fc+ via a one‐electron diffusion controlled process with anodic (ip°x) to cathodic (ipred) peak current ratios (ip°x/ipred)≫1, suggesting that the produced phenoxyl radicals decomposed rapidly via a chemical step. However, electron paramagnetic resonance (EPR) experiments performed on the bulk electrolyzed solutions of the phenolates after one‐electron bulk oxidation indicated long lifetimes of the UV234. and UV327. phenoxyl radicals. Therefore, the long timescale CPE and spectroscopic (UV‐vis and EPR) studies provided good evidence of a reversible dimerization mechanism between the phenoxyl radicals, which explained the apparent discrepancy with the short timescale CV experiments.
Indirect 3D Printed Electrode Mixers
Authors: Hereijgers Jonas , Schalck Jonathan , Lölsberg Jonas , Wessling Matthias , Breugelmans Tom
Published: October 2018

Electrode mixers are ordered 3D flow‐through structures with mixing properties that at the same time act as electrode. Because of their mixing properties, these structures enhance mass transfer at the electrode surface, increasing the limiting‐current plateau. Typically operating at this plateau, the productivity of electrochemical reactors is limited by the mass transport of the reagents. This work presents the fabrication of all‐metal electrode mixers through an indirect 3D printing method. Whereas other techniques suffer from design limitations or come with high capital cost, the proposed rapid prototyping method overcomes these limitations. Using this method, a helical and a cubic electrode mixer was fabricated and their mass transfer properties were characterized and compared to a flat electrode by the limiting current method. Increasing the mass transfer up to 47 % the standard flat electrode is outperformed, demonstrating the valorization potential of electrode mixers and the indirect 3D printing method.
Multistep Wavelength Switching of Near‐Infrared Photoluminescence Driven by Chemical Reactions at Local Doped Sites of Single‐Walled Carbon Nanotubes
Authors: Shiraki Tomohiro , Shiga Tamehito , Shiraishi Tomonari , Onitsuka Hisashi , Nakashima Naotoshi , Fujigaya Tsuyohiko
Published: October 2018

Local chemical functionalization is used for defect doping of single‐walled carbon nanotubes (SWNTs), to develop near‐infrared photoluminescence (NIR PL) properties. We report the multistep wavelength shifting of the NIR PL of SWNTs through chemical reactions at local doped sites tethered to an arylaldehyde group. The PL wavelength of the doped SWNTs is modulated based on imine chemistry. This involves the imine formation of aldehyde groups with added arylamines, imine dissociation reaction, exchange reaction of bound arylamines in the imine, and the Kabachnik–Fields reaction of imine groups using diisopropyl phosphite. Using doped sites as a localized chemical reaction platform can exploit the versatile molecularly driven functionality of carbon nanotubes and related nanomaterials.
Structure–Activity Relationships of Antiplasmodial Pantothenamide Analogues Reveal a New Way by Which Triazoles Mimic Amide Bonds
Authors: Guan Jinming , Tjhin Erick T. , Howieson Vanessa M. , Kittikool Tanakorn , Spry Christina , Saliba Kevin J. , Auclair Karine
Published: October 2018

Pantothenamides are potent growth inhibitors of the malaria parasite Plasmodium falciparum. Their clinical use is, however, hindered due to the ubiquitous presence of pantetheinases in human serum, which rapidly degrade pantothenamides into pantothenate and the corresponding amine. We previously reported that replacement of the labile amide bond with a triazole ring not only imparts stability toward pantetheinases, but also improves activity against P. falciparum. A small library of new triazole derivatives was synthesized, and their use in establishing structure–activity relationships relevant to antiplasmodial activity of this family of compounds is discussed herein. Overall it was observed that 1,4‐substitution on the triazole ring and use of an unbranched, one‐carbon linker between the pantoyl group and the triazole are optimal for inhibition of intraerythrocytic P. falciparum growth. Our results imply that the triazole ring may mimic the amide bond with an orientation different from what was previously suggested for this amide bioisostere.
The hidden costs of surviving childhood cancer
Authors: Nelson Bryn
Published: October 2018

This news section is written by a medical journalist and offers Cancer Cytopathology readers timely information on events, issues, and personalities of interest to the subspecialty. This edition explores the hidden costs of surviving childhood cancer, including health issues that develop later in life in patients who survived pediatric cancers.
Female zebra finches do not sing yet share neural pathways necessary for singing in males
Authors: Shaughnessy Derrick W. , Hyson Richard L. , Bertram Richard , Wu Wei , Johnson Frank
Published: October 2018

Adult female zebra finches (Taeniopygia guttata), which do not produce learned songs, have long been thought to possess only vestiges of the forebrain network that supports learned song in males. This view ostensibly explains why females do not sing—many of the neural populations and pathways that make up the male song control network appear rudimentary or even missing in females. For example, classic studies of vocal‐premotor cortex (HVC, acronym is name) in male zebra finches identified prominent efferent pathways from HVC to vocal‐motor cortex (RA, robust nucleus of the arcopallium) and from HVC to the avian basal ganglia (Area X). In females, by comparison, the efferent targets of HVC were thought to be only partially innervated by HVC axons (RA) or absent (Area X). Here, using a novel visually guided surgical approach to target tracer injections with precision, we mapped the extrinsic connectivity of the adult female HVC. We find that female HVC shows a mostly male‐typical pattern of afferent and efferent connectivity, including robust HVC innervation of RA and Area X. As noted by earlier investigators, we find large sex differences in the volume of many regions that control male singing (male > female). However, sex differences in volume were diminished in regions that convey ascending afferent input to HVC. Our findings do not support a vestigial interpretation of the song control network in females. Instead, our findings support the emerging view that the song control network may have an altogether different function in nonsinging females.
Genetic scheduling policy on codelet model
Authors: Pei Songwen , Wang Jinkai , Jiang Linhua , Xiong Naixue , Gaudiot Jean‐Luc
Published: October 2018

The Codelet Model is a fine‐grained event‐driven hybrid parallel model inspired by dataflow, whose computing performance depends on the scheduling policy. An approximate optimal codelet scheduling policy based on the features of the task graphs is important to accelerate the performance of dataflow computer system. Therefore, we have proposed an adaptive genetic scheduling policy (GSP) for codelet by improving a “pure” genetic algorithm (IPGA) for given tasks with complex dependencies. It is verified that the genetic scheduling policy is effective according to bunches of experimental results.
The Structural Signs of Sweetness in Artificial Sweeteners: A Rotational Study of Sorbitol and Dulcitol
Authors: Alonso Elena R. , León Iker , Kolesniková Lucie , Alonso Jose L.
Published: October 2018

A gas‐phase study on the artificial sweeteners sorbitol and dulcitol has been carried out for the first time by using a combination of chirped‐pulse Fourier‐transform microwave (CP‐FTMW) spectroscopy and laser ablation (LA). The isolation conditions provided by the supersonic expansion reveal the intrinsic conformational structures of these sweeteners. The three and five observed conformers for sorbitol and dulcitol, respectively, are stabilized by networks of cooperative intramolecular hydrogen bonds between vicinal hydroxyl groups in clockwise or counterclockwise arrangements. Suitable places in the structure of seven out of eight conformers identified for both polyalcohols meet the requirements of the glucophore proposed by Shallenberger and Acree's molecular theory of sweet taste. Present results provide the first linkage between sweetness and structure in sugar alcohols.
Hollow Polypyrrole Nanospindles for Highly Effective Cancer Therapy
Authors: Chen Yixin , Xiang Siyuan , Wang Lu , Wang Mingyue , Wang Congcong , Liu Shuwei , Zhang Kai , Yang Bai
Published: October 2018

Polypyrrole (PPy) hollow nanostructures continue to attract the interest researchers because of their good biocompatibility, high photothermal conversion efficiency, and excellent stability. The preparation of PPy hollow nanostructures by the hard templating method without complicated post‐synthetic treatment and additional oxidizing agents remains a challenge. In this work, we report a facile and novel hard templating method to fabricate hollow PPy nanospindles in which MIL‐88(Fe) serves as the template. Fe3+ centers in MIL‐88(Fe) could induce the polymerization of pyrrole to construct the shell, and MIL‐88(Fe) would be decomposed by solvent water. This method did not require any extra oxidizing agents and post‐synthetic treatment. Hollow PPy nanospindles exhibit excellent photothermal and drug loading ability, and the therapy effect of cancer was significant. This method provides a new hard templating approach for the synthesis of polymer hollow nanostructures.
Stereoselective Synthesis of Tetrahydroquinolines via Asymmetric Domino Reaction Catalyzed by a Recyclable Ionic‐Liquid‐Supported Bifunctional Tertiary Amine
Authors: Tukhvatshin Rinat S. , Kucherenko Alexander S. , Nelyubina Yulia V. , Zlotin Sergei G.
Published: October 2018

The most recyclable ionic liquid‐supported bifunctional tertiary amine–squaramide organocatalyst for the asymmetric domino reaction has been found. Over this catalyst, ortho‐aminochalcones protected with Tosyl or Nosyl groups underwent the aza‐Michael/Michael domino reaction with nitroolefins to afford corresponding 2,3,4‐trisubstituted tetrahydroquinolines as single diastereomers in nearly quantitative yield with up to 99 % ee. The catalyst was readily separated from the reaction mixture via a simple centrifugation/decantation workup and 19 times reused in the catalytic reaction without noticeable conversion or enantioselectivity reduction. The N‐nosylated products proved their synthetic value for pharmacology given their facile conversion to fused pirrolidino‐tetrahydroquinolines of high diastreomeric and enantiomeric purity via successive deprotection and reductive amination.
A Domino Epoxide Ring‐Opening Xanthate Migration Reaction: An Alternative Entry to Thiosugars
Authors: Comba María B. , Mangione María I. , Suárez Alejandra G. , Sarotti Ariel M. , Spanevello Rolando A.
Published: October 2018

A sterereospecific and efficient synthesis of thiosugars derived from levoglucosenone and methyl α‐d‐glucopyranoside was developed by a domino epoxide ring opening‐ xanthate migration to afford 1,3‐oxathiolane‐2‐thiones in high yields. The stereochemical outcome of the new C–S bond was defined by the configuration of the starting materials. The 1,3‐oxathiolane‐2‐thiones were subsequently submitted to a second tandem reaction affording the corresponding 2,3‐episulfide alcohols. The thiosugars obtained are useful building blocks for the synthesis of thiooligosaccharides with potential biological properties.
Digitization of weekly Murrumbidgee River heights at Hay South Eastern Australia 1873–2017
Authors: Speer M. S.
Published: October 2018

Long‐term, high‐frequency river height measurements provide a direct method of relating changes in local water availability in a catchment to such phenomena as climate and changes in land use. Here, digitized weekly river height data from the Murrumbidgee River at Hay in south eastern Australia are presented for the first time covering the start of record from November 1873 to June 2017. There are two gauge board locations: (a) The town gauge at the southern edge of the township with data until March 1983, and (b) the Hay Private Irrigation District (PID) gauge on the north eastern outskirts of Hay about 2 km upstream from the Hay town gauge. There is a data overlap of about 13 years for the two locations. The underlying data quality is good taking into account missing values, outliers, continuity between the two gauge locations and measurement practice. The weekly data are available in both annual and seasonal files.

Open Practices

This article has earned an Open Data badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at http://doi.org/10.5281/zenodo.1184869. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.
A limited capacity for microglial repopulation in the adult brain
Authors: Najafi Allison R. , Crapser Joshua , Jiang Shan , Ng Winnie , Mortazavi Ali , West Brian L. , Green Kim N.
Published: October 2018

Microglia are the resident immune cell of the central nervous system (CNS), and serve to protect and maintain the local brain environment. Microglia are critically dependent on signaling through the colony‐stimulating factor 1 receptor (CSF1R); administration of CSF1R inhibitors that cross the blood brain barrier (BBB) lead to the elimination of up to 99% of microglia, depending on CNS exposure and treatment duration. Once microglia are depleted, withdrawal of inhibitor stimulates repopulation of the entire CNS with new cells, conceivably enabling a therapeutic strategy for beneficial renewal of the entire microglial tissue. We have explored the kinetics and limits of this repopulation event and show that the rate of microglial repopulation is proportional to the extent of microglial depletion – greater depletion of microglia results in more rapid repopulation. Using a CSF1R inhibitor formulation that eliminates approximately 99% of microglia within 7 days, we subjected mice to multiple rounds of elimination (7 days’ treatment) and repopulation (7 days’ recovery) and found that the brain only has the capacity for a single complete repopulation event; subsequent elimination and CSF1R inhibitor withdrawal fail to repopulate the brain. However, if the recovery time between, or after, cycles is extended sufficiently then the brain can ultimately repopulate. These kinetic studies define the opportunities and possible limits of the remarkable renewal capacities of microglia.