bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomimetic Supertough and Strong Biodegradable Polymeric Materials with Improved Thermal Properties and Excellent UV‐Blocking Performance
Authors: Zhang Xiao , Liu Weifeng , Yang Dongjie , Qiu Xueqing 
Published: December 2018

AbstractThe preparation of biodegradable polymeric materials with both great strength and toughness remains a huge challenge. The natural spider silk exhibits a combined super high tensile strength and high fracture toughness (150–190 J g−1), attributing to the hierarchically assembled nanophase separation and the densely organized sacrificial hydrogen bonds confined in the nanoscale granules. Herein, inspired by natural spider silk, a facile strategy is reported for the preparation of nanostructured biomimetic polymeric material by incorporating biomass‐derived lignosulfonic acid (LA) as interspersed nanoparticles into a biodegradable poly(vinyl alcohol) (PVA) matrix. The fabricated PVA/LA nanocomposite film exhibits the world's highest toughness of 172 (±5) J g−1 among the PVA materials, as well as a powerful tensile strength of 98.2 MPa and a large breaking strain of 282%. The outstanding performance is attributed to the strain‐induced scattering of LA nanoparticles in the PVA matrix and the strong intermolecular sacrificial hydrogen bonds confined in the interphase. Moreover, after introducing the easily available green biomass LA, the prepared biomimetic polymer films show excellent ultraviolet‐blocking performance and good thermal stability. As both PVA and LA are biodegradable, this work presents an innovative design strategy for fully biodegradable robust polymeric materials with integrated strength and toughness.
Biocompatible Soft Fluidic Strain and Force Sensors for Wearable Devices
Authors: Xu Siyi , Vogt Daniel M. , Hsu Wen‐Hao , Osborne John , Walsh Timothy , Foster Jonathan R. , Sullivan Sarah K. , Smith Vincent C. , Rousing Andreas W. , Goldfield Eugene C. , Wood Robert J. 
Published: December 2018

AbstractFluidic soft sensors have been widely used in wearable devices for human motion capturing. However, thus far, the biocompatibility of the conductive liquid, the linearity of the sensing signal, and the hysteresis between the loading and release processes have limited the sensing quality as well as the applications of these sensors. In this paper, silicone based strain and force sensors composed of a novel biocompatible conductive liquid (potassium iodide and glycerol solution) are introduced. The strain sensors exhibit negligible hysteresis up to 5 Hz, with a gauge factor of 2.2 at 1 Hz. The force sensors feature a novel multifunctional layered structure, with microcylinder‐filled channels to achieve high linearity, low hysteresis (5.3% hysteresis at 1 Hz), and good sensitivity (100% resistance increase at a 5 N load). The sensors' gauge factors are stable at various temperatures and humidity levels. These biocompatible, low hysteresis, and high linearity sensors are promising for safe and reliable diagnostic devices, wearable motion capture, and compliant human–computer interfaces.
Ultrathin MoO3 Layers in Composite Metal Electrodes: Improved Optics Allow Highly Efficient Organic Light‐Emitting Diodes
Authors: Li Yungui , Tang Zheng , Hänisch Christian , Will Paul‐Anton , Kovačič Milan , Hou Ji‐Ling , Scholz Reinhard , Leo Karl , Lenk Simone , Reineke Sebastian 
Published: December 2018

AbstractMolybdenum trioxide (MoO3) has been investigated as a seeding and energy‐level modification layer for ultrathin metal electrode in organic light‐emitting diodes (OLEDs). However, the optical effect of this interlayer has not been addressed so far. In this article, the influence of the thin MoO3 layer for bottom emitting OLEDs is thoroughly investigated. It is noted that a thin MoO3 layer has a substantial impact on the device performance through inducing a synergistic effect of suppressing the nonradiative surface plasmon polariton (SPP) modes and modulating the cavity resonance. In presence of MoO3 layer, the SPP mode is suppressed from 400 to 520 nm. Moreover, introducing a thin MoO3 layer reduces the reflectance of the Au/Ag electrode, resulting in a decreased destructive resonance in devices. These combined effects enable to build highly efficient OLEDs, with the external quantum efficiency and luminous efficacy of two‐unit stacked white OLEDs reaching 38.8% and 53.9 lm W−1 at 1000 cd m−2, when substrate and air modes are extracted. The efficiency is about 1.9 times higher compared to the one without MoO3 layer. The result provides insights into indium tin oxide free optoelectronic devices, as well as light extraction strategy and color purity manipulations for OLEDs.
Optimized Electrolyte Loading and Active Film Thickness for Sandwich Polymer Light‐Emitting Electrochemical Cells
Authors: Diethelm Matthias , Grossmann Quirin , Schiller Andreas , Knapp Evelyne , Jenatsch Sandra , Kawecki Maciej , Nüesch Frank , Hany Roland 
Published: December 2018

AbstractEffects of ion concentration and active layer thickness play a critical role on the performance of light‐emitting electrochemical cells. Expanding on a pioneering materials system comprising the super yellow (SY) polymer and the electrolyte trimethylolpropane ethoxylate (TMPE)/Li+CF3SO3−, it is reported that a slightly lowered salt concentration and layer thickness result in a substantial efficiency increase, and that this increase is confined to a narrow concentration and thickness range. For a film thickness of 70 nm, a blend ratio SY:TMPE:Li+CF3SO3− = 1:0.075:0.0225, and a current of 7.7 mA cm−2 the current efficacy is 11.6 cd A−1, on a par with SY light‐emitting diodes. The optimized salt content can be explained by increased exciton quenching at higher concentrations and hindered carrier injection and conduction at lower concentrations, while the optical dependence on the layer thickness is due to weak microcavity effects. A comprehensive optical modeling study is presented, which includes the doping‐induced changes of the refractive indices and self‐absorption losses due the emission–absorption overlap of intrinsic and doped SY. The analysis indicates either a thickness‐independent emitter position (EP) close to the anode or a thickness‐dependent EP, shifted to the cathode for increased thicknesses.
Manipulating Terahertz Plasmonic Vortex Based on Geometric and Dynamic Phase
Authors: Zang XiaoFei , Zhu YiMing , Mao ChenXi , Xu WeiWei , Ding HongZhen , Xie JingYa , Cheng QingQing , Chen Lin , Peng Yan , Hu Qing , Gu Min , Zhuang SongLin 
Published: December 2018

AbstractElectromagnetic waves carrying orbital angular momentum (OAM), namely, vortex beams, have a plethora of applications ranging from rotating microparticles to high‐capacity data transmissions, and it is a continuing trend in manipulating OAM with higher degrees of freedom. Here, an approach to control terahertz (THz) near‐field plasmonic vortex based on geometric and dynamic phase is proposed and experimentally demonstrated. By locally tailoring the orientation angle (geometric phase) and radial position (dynamic phase) of aperture arrays embedded in an ultrathin gold film, the excited surface waves can be flexibly engineered to form both spin‐independent and spin‐dependent THz plasmonic vortex field distributions, resulting in multi‐degree of freedom for controlling OAM of THz surface plasmon polaritons (SPPs). Arbitrary OAM values of THz plasmonic vortex and coherent superposition between two OAM states are investigated based on near‐field scanning terahertz microscopy (NSTM) system. The proposed approach provides unprecedented freedom to modulate THz near‐field plasmonic vortex, which will have potential applications in THz communications and quantum information processing.
Nanoscale Bacteria‐Enabled Autonomous Drug Delivery System (NanoBEADS) Enhances Intratumoral Transport of Nanomedicine
Authors: Suh SeungBeum , Jo Ami , Traore Mahama A. , Zhan Ying , Coutermarsh‐Ott Sheryl L. , Ringel‐Scaia Veronica M. , Allen Irving C. , Davis Richey M. , Behkam Bahareh 
Published: December 2018

AbstractCancer drug delivery remains a formidable challenge due to systemic toxicity and inadequate extravascular transport of nanotherapeutics to cells distal from blood vessels. It is hypothesized that, in absence of an external driving force, the Salmonella enterica serovar Typhimurium could be exploited for autonomous targeted delivery of nanotherapeutics to currently unreachable sites. To test the hypothesis, a nanoscale bacteria‐enabled autonomous drug delivery system (NanoBEADS) is developed in which the functional capabilities of the tumor‐targeting S. Typhimurium VNP20009 are interfaced with poly(lactic‐co‐glycolic acid) nanoparticles. The impact of nanoparticle conjugation is evaluated on NanoBEADS' invasion of cancer cells and intratumoral transport in 3D tumor spheroids in vitro, and biodistribution in a mammary tumor model in vivo. It is found that intercellular (between cells) self‐replication and translocation are the dominant mechanisms of bacteria intratumoral penetration and that nanoparticle conjugation does not impede bacteria's intratumoral transport performance. Through the development of new transport metrics, it is demonstrated that NanoBEADS enhance nanoparticle retention and distribution in solid tumors by up to a remarkable 100‐fold without requiring any externally applied driving force or control input. Such autonomous biohybrid systems could unlock a powerful new paradigm in cancer treatment by improving the therapeutic index of chemotherapeutic drugs and minimizing systemic side effects.
Interfacial Scaffolding Preparation of Hierarchical PBA‐Based Derivative Electrocatalysts for Efficient Water Splitting
Authors: Wang Yueqing , Ma Jizhen , Wang Jun , Chen Si , Wang Huaisheng , Zhang Jintao 
Published: December 2018

AbstractThe development of highly efficient and durable electrocatalysts is crucial for overall water splitting. Herein, the in situ scaffolding formation of 3D Prussian blue analogues (PBAs) on a variety of 2D or 1D metal hydroxides/oxides to fabricate hierarchical nanostructures is first demonstrated. Typically, cobalt hydroxide or oxide nanoarrays are used as the precursor and structural oriented template for the subsequent growth of 3D PBA nanocubes. The mechanism study reveals that the interfacial scaffolding process can be reversibly controlled via the in situ ion exchange process with adjusting coordination ions. Thus, the facile, versatile strategy can extend to successfully fabricate a variety of hierarchical PBA‐based nanostructures including on cobalt fluoride hydroxide, copper hydroxide, monometal or bimetal nickel–cobalt hydroxides, cobalt oxide, and manganese oxide nanosheets with structural tailor‐ability and chemical diversity. More interestingly, the metal nitride derivatives obtained via controlled calcination process exhibit good electrocatalytic activity for water splitting with low overpotentials, and remarkable durability for 1200 h, thanks to the superior intrinsic activity of bimetal nature and the scrupulous hierarchical structure. This versatile strategy provides a paradigm for rational design of PBA‐based functional nanomaterials, which is highly promising in energy conversion, storage, and electrocatalytic fields.
Introduction of d‐Amino Acids in Minimalistic Peptide Substrates by an S‐Adenosyl‐l‐Methionine Radical Epimerase
Authors: Vagstad Anna L. , Kuranaga Takefumi , Püntener Salome , Pattabiraman Vijaya R. , Bode Jeffrey W. , Piel Jörn 
Published: December 2018

AbstractPost‐translational modifying enzymes from the S‐adenosyl‐l‐methionine (AdoMet) radical superfamily garner attention due to their ability to accomplish challenging biochemical reactions. Among them, a family of AdoMet radical epimerases catalyze irreversible l‐ to d‐amino acid transformations of diverse residues, including 18 sites in the complex sponge‐derived polytheonamide toxins. Herein, the in vitro activity of the model epimerase OspD is reported and its catalytic mechanism and substrate flexibility is investigated. The wild‐type enzyme was capable of leader‐independent epimerization of not only the stand‐alone core peptide, but also truncated and cyclic core variants. Introduction of d‐amino acids can drastically alter the stability, structure, and activity of peptides; thus, epimerases offer opportunities in peptide bioengineering.
Multi‐Light‐Responsive Quantum Dot Sensitized Hybrid Micromotors with Dual‐Mode Propulsion
Authors: María Hormigos Roberto , Jurado Sánchez Beatriz , Escarpa Alberto 
Published: December 2018

AbstractCdS quantum dots/C60 tubular micromotors with chemical/multi‐light‐controlled propulsion and “on‐the‐fly” acceleration capabilities are described. In situ growth of CdS quantum dots on the outer fullerene layer imparts this layer with light‐responsive properties in connection to inner Pt, Pd or MnO2 layers. This is the first time that visible light is used to drive bubble‐propelled tubular micromotors. The micromotors exhibit a broad absorption range from 320 to 670 nm and can be wirelessly controlled by modulating light intensity and peroxide concentration. The built‐in accelerating optical system allows for the control of the velocity over the entire UV/Vis light spectra by modulating the catalyst surface chemistry. The light‐responsive properties have been also exploited to accelerate the chemical dealloying and propulsion of micromotors containing a Cu/Pd layer. Such dual operated hybrid micromotors hold considerable promise for designing smart micromachines for on‐demand operations, motion‐based sensing, and enhanced cargo transportation.
Orientation of an Amphiphilic Copolymer to a Lamellar Structure on a Hydrophobic Surface and Implications for CO2 Capture Membranes
Authors: Park Cheol Hun , Lee Jae Hun , Jung Jung Pyo , Lee Wooseop , Ryu Du Yeol , Kim Jong Hak 
Published: December 2018

AbstractThe structural orientation of an amphiphilic crystalline polymer to a highly ordered microphase‐separated lamellar structure on a hydrophobic surface is presented. It is formed by the surface graft polymerization of poly(ethylene glycol)behenyl ether methacrylate onto poly(trimethylsilyl) propyne in the presence of allylamine. In particular, allylamine plays a pivotal role in controlling the crystalline phase, configuration, and permeation properties. The resulting materials are effectively used to improve the CO2 capture property of membranes. Upon the optimization of the reaction conditions, a high CO2 permeability of 501 Barrer and a CO2/N2 ideal selectivity of 77.2 are obtained, which exceed the Robeson upper bound limit. It is inspiring to surpass the upper bound limit via a simple surface modification method.
Carbon‐Supported Divacancy‐Anchored Platinum Single‐Atom Electrocatalysts with Superhigh Pt Utilization for the Oxygen Reduction Reaction
Authors: Liu Jing , Jiao Menggai , Mei Bingbao , Tong Yuxin , Li Yuping , Ruan Mingbo , Song Ping , Sun Gongquan , Jiang Luhua , Wang Ying , Jiang Zheng , Gu Lin , Zhou Zhen , Xu Weilin 
Published: December 2018

AbstractMaximizing the platinum utilization in electrocatalysts toward oxygen reduction reaction (ORR) is very desirable for large‐scale sustainable application of Pt in energy systems. A cost‐effective carbon‐supported carbon‐defect‐anchored platinum single‐atom electrocatalysts (Pt1/C) with remarkable ORR performance is reported. An acidic H2/O2 single cell with Pt1/C as cathode delivers a maximum power density of 520 mW cm−2 at 80 °C, corresponding to a superhigh platinum utilization of 0.09 gPt kW−1. Further physical characterization and density functional theory computations reveal that single Pt atoms anchored stably by four carbon atoms in carbon divacancies (Pt‐C4) are the main active centers for the observed high ORR performance.
Enantiospecific Synthesis of ortho‐Substituted 1,1‐Diarylalkanes by a 1,2‐Metalate Rearrangement/anti‐SN2′ Elimination/Rearomatizing Allylic Suzuki–Miyaura Reaction Sequence
Authors: Rubial Belén , Collins Beatrice S. L. , Bigler Raphael , Aichhorn Stefan , Noble Adam , Aggarwal Varinder K. 
Published: December 2018

AbstractThe one‐pot sequential coupling of benzylamines, boronic esters, and aryl iodides has been investigated. In the presence of an N‐activator, the boronate complex formed from an ortho‐lithiated benzylamine and a boronic ester undergoes stereospecific 1,2‐metalate rearrangement/anti‐SN2′ elimination to form a dearomatized tertiary boronic ester. Treatment with an aryl iodide under palladium catalysis leads to rearomatizing γ‐selective allylic Suzuki–Miyaura cross‐coupling to generate 1,1‐diarylalkanes. When enantioenriched α‐substituted benzylamines are employed, the corresponding 1,1‐diarylalkanes are formed with high stereospecificity.
Synthesis of C−C Bonded Two‐Dimensional Conjugated Covalent Organic Framework Films by Suzuki Polymerization on a Liquid–Liquid Interface
Authors: Zhou Deng , Tan Xianyang , Wu Huimin , Tian Lihong , Li Ming 
Published: December 2018

AbstractSynthesis of free‐standing two‐dimensional (2D) conjugated covalent organic framework (COF) films linked by C−C bonds is highly desirable. Now a very simple and mild strategy has been developed to synthesize them by Suzuki polymerization on a water–toluene interface in a refrigerator. The versatility of this strategy was confirmed by the successful synthesis of two different 2D‐COF films: a porous graphene and a porphyrin‐contained 2D‐COF. Both 2D‐COF films have large lateral size and their crystalline domains were visualized by high resolution TEM. Based on the wide compatibility of Suzuki reaction, our breakthrough work opened a door for the synthesis of various 2D conjugated COF films. For application studies, the porous graphene exhibits a good carrier mobility, which is much higher than −C=N− linked 2D COF films and a good catalytic activity for hydrogen evolution reaction, which is comparable with nitrogen‐ or phosphorus‐doped graphene.
Oxidative Addition to Palladium(0) Made Easy through Photoexcited‐State Metal Catalysis: Experiment and Computation
Authors: Kancherla Rajesh , Muralirajan Krishnamoorthy , Maity Bholanath , Zhu Chen , Krach Patricia E. , Cavallo Luigi , Rueping Magnus 
Published: December 2018

AbstractVisible‐light induced, palladium catalyzed alkylations of α,β‐unsaturated acids with unactivated alkyl bromides are described. A variety of primary, secondary, and tertiary alkyl bromides are activated by the photoexcited palladium metal catalyst to provide a series of olefins at room temperature under mild reaction conditions. Mechanistic investigations and density functional theory (DFT) studies suggest that a photoinduced inner‐sphere mechanism is operative in which a barrierless, single‐electron transfer oxidative addition of the alkyl halide to Pd0 is key for the efficient transformation.
PIII‐Chelation‐Assisted Indole C7‐Arylation, Olefination, Methylation, and Acylation with Carboxylic Acids/Anhydrides by Rhodium Catalysis
Authors: Qiu Xiaodong , Wang Panpan , Wang Dingyi , Wang Minyan , Yuan Yu , Shi Zhuangzhi 
Published: December 2018

AbstractRhodium‐catalyzed C7‐selective decarbonylative arylation, olefination, and methylation of indoles with carboxylic acids or anhydrides by C−H and C−C bond activation have been developed. Furthermore, C7‐acylation products can also be generated selectively at a lower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N‐PtBu2 chelation‐assisted group. This method has many advantages, including easy access and removal of the directing group, the use of cheap and widely available coupling agents, no requirement of an external ligand or oxidant, a broad substrate scope, high efficiency, and the formation of a sole regioisomer.
Tripyridine‐Derivative‐Derived Semiconducting Iodo‐Argentate/Cuprate Hybrids with Excellent Visible‐Light‐Induced Photocatalytic Performance
Authors: Wei Qi , Ge Bang‐Di , Zhang Jing , Sun Ai‐Huan , Li Jin‐Hua , Han Song‐De , Wang Guo‐Ming 
Published: December 2018

AbstractThrough regulating the pH values, a series of iodo‐argentate/cuprate hybrids, [Me3(4‐TPT)]4[Ag6I18] (1, Me3(4‐TPT)=N,N′,N′′‐trimethyl‐2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine), [Me3(4‐TPT)][M5I8] (M=Ag/2, Cu/2 a), [Me3(3‐TPT)][M5I8] (Me3(3‐TPT)=N,N′,N′′‐trimethyl‐2,4,6‐tris(3‐pyridyl)‐1,3,5‐triazine, M=Ag/3, Cu/4), which exhibit adjustable structural variations with different dimensional structures, have been obtained under solvothermal conditions. They are directed by two types of in situ N‐alkylation TPT‐derivatives (Me3(4‐TPT) for 1/2/2 a and Me3(3‐TPT) for 3/4) and represent the isolated units (1), 1D polymeric chain (4), 2D layered structures (2/2 a, 3) based on diverse metal iodide clusters. These compounds possess reducing band gaps as compared with the bulk β‐AgI and CuI and belong to potential semiconductor materials. Iodocuprates feature highly efficient photocatalytic activity in the sunlight‐induced degradation of organic dyes. The detailed study on the possible photocatalytic mechanism, including radical trapping tests and theoretical calculations, reveals that the N‐alkylation TPT moieties contribute to the narrow semiconducting behavior and effectively inhibit the recombination of photogenerated electron‐hole pairs, which result in an excellent visible‐light‐induced photocatalytic performance.
Water‐Soluble Pillar[n]arene Mediated Supramolecular Self‐Assembly: Multi‐Dimensional Morphology Controlled by Host Size
Authors: Liu Yamin , Shi Kejia , Ma Da 
Published: December 2018

AbstractWe report tunable supramolecular self‐assemblies formed by water‐soluble pillar[n]arenes (WPns, n=5–7) and bipyridinium‐azobenzene guests. Nanoscale or microscale morphology of self‐assemblies in water was controlled by the host size of WPn. Supramolecular self‐assemblies could undergo morphology conversion under irradiation with UV light.