bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithiophilic 3D Nanoporous Nitrogen‐Doped Graphene for Dendrite‐Free and Ultrahigh‐Rate Lithium‐Metal Anodes
Authors: Huang Gang , Han Jiuhui , Zhang Fan , Wang Ziqian , Kashani Hamzeh , Watanabe Kentaro , Chen Mingwei 
Published: November 2018

AbstractThe key bottlenecks hindering the practical implementations of lithium‐metal anodes in high‐energy‐density rechargeable batteries are the uncontrolled dendrite growth and infinite volume changes during charging and discharging, which lead to short lifespan and catastrophic safety hazards. In principle, these problems can be mitigated or even solved by loading lithium into a high‐surface‐area, conductive, and lithiophilic porous scaffold. However, a suitable material that can synchronously host a large loading amount of lithium and endure a large current density has not been achieved. Here, a lithiophilic 3D nanoporous nitrogen‐doped graphene as the sought‐after scaffold material for lithium anodes is reported. The high surface area, large porosity, and high conductivity of the nanoporous graphene concede not only dendrite‐free stripping/plating but also abundant open space accommodating volume fluctuations of lithium. This ingenious scaffold endows the lithium composite anode with a long‐term cycling stability and ultrahigh rate capability, significantly improving the charge storage performance of high‐energy‐density rechargeable lithium batteries.
Printable Liquid‐Metal@PDMS Stretchable Heater with High Stretchability and Dynamic Stability for Wearable Thermotherapy
Authors: Wang Yuxin , Yu Zhe , Mao Guoyong , Liu Yiwei , Liu Gang , Shang Jie , Qu Shaoxing , Chen Qingming , Li Run‐Wei 
Published: November 2018

AbstractAs a type of flexible electronics, wearable heaters have attracted broad attention because of their giant potential market value, such as for use in wearable thermotherapy. Wearable heaters are required to simultaneously possess high stretchability and dynamic stability, in order to realize joints or muscles thermotherapy during exercising. Here, a high‐performance electrically driven heater using the conductive composite of liquid‐metal (LM) and polydimethylsiloxane (PDMS) is reported, which is patterned as sinusoidal structure by the printing technology of direct ink writing. Because high conductive LM is chosen as the active material, the LM@PDMS stretchable heater possesses high stretchability (>100% strain) and good conductivity (1.81 × 103 S cm−1). It also exhibits superb dynamic stability, due to the 3D conductive network of LM in matrix and the sinusoidal structure of the composite. While being stretched to the strain level of 100%, the heating temperature variation of LM@PDMS stretchable heater is less than 8%. This relatively low temperature variation is several times smaller than that of existing heaters at the same large strain levels. It is demonstrated that the LM@PDMS stretchable heater worn on the knee joint works well during strenuous exercise, thus proving great potential in wearable thermotherapy.
Bare Silica Opals for Real‐Time Humidity Sensing
Authors: Gallego‐Gómez Francisco , Morales Miguel , Blanco Alvaro , López Cefe 
Published: November 2018

AbstractThe photonic properties of 3D colloidal crystals made of Stöber silica spheres are shown to significantly depend on the relative humidity of the environment. The photonic bandgap of bare artificial opals formed by hydrophilic silica markedly varies in humid air along the entire range of water vapor concentration without the need for infiltration of functionalization. The optical changes are highly sensitive to humidity variation (especially in low‐humidity range) and very fast response times of 60 ms, mainly ascribed to the absence of intermediate processes, the favorable bandgap characteristics (high intensity and sharp edges) and the high air accessibility to the open opal voids. Contrary to common approaches for photonic crystal sensors—seeking visual detection via large spectral shifts but having important shortcomings,—it is demonstrated that the well‐defined photonic bandgap of bare silica opals allows, even for moderate shifts, outstanding sensing performance by proper monitoring with inexpensive equipment (no spectroscopic detection is needed). As a result, the rapid and reproducible photonic response enables accurate, real‐time retrieval of the ambient humidity. The economical, one‐step fabrication, and the efficient performance make silica artificial opals suitable for a new type of precise, low‐cost, and real‐time humidity sensors.
Composite Structures with Emissive Quantum Dots for Light Enhancement
Authors: Smith Marcus J. , Lin Chun Hao , Yu Shengtao , Tsukruk Vladimir V. 
Published: November 2018

AbstractSince their inception, quantum dots have proven to be advantageous for light management applications due to their high brightness and well‐controlled absorption, scattering, and emission properties. As quantum dots become commercially available at large scale, the need for robust, stable, and flexible optical components continues to drive the development of robust and flexible quantum dot composite materials. In this review, after a thorough introduction to quantum dots, discussion delves into methods for fabricating quantum dot loaded composite optical elements such as thin films, microfabricated patterns, and microstructures. The importance of surface chemistry and ligand engineering, host matrixes, wet processing, and unique patterning methodologies is presented by considering photostability, aggregation, and phase separation of quantum dots in corresponding composites. With regard to prospective optical applications of quantum dot materials, emphasis is placed on light emitting and guiding composite materials for lasing applications, specifically whispering gallery mode‐based photonic microsystems. These developments will enable novel flexible, portable, and miniaturized optoelectronic devices such as light‐emitting diodes, flexible pixelated displays, solar cells, large‐area microwaveguides, omnidirectional micromirrors, optical metasurfaces, and directional microlasers.
Reusable Palladium Nanoparticles Catalyzed Oxime Ether Directed Mono Ortho‐Hydroxylation under Phosphine Free Neutral Condition
Authors: Saha Rajib , Perveen Naziya , Nihesh Naorem , Sekar Govindasamy 
Published: November 2018

AbstractAn efficient, reusable and stable binaphthyl stabilized Pd‐nanoparticles (Pd‐BNP) catalyzed the direct ortho‐C−H hydroxylation of acetophenone oxime ethers under neutral and phosphine ligand‐free condition has been developed. A readily available, economic, safe and greener oxidant oxone has been used in this direct ortho‐hydroxylation. The scope of the reaction has been studied with various acetophenone oxime ethers including electron rich to electron deficient system and the reaction afforded only mono hydroxylated products in a highly regioselective manner. Several control experiment results confirmed that the oxone is the hydroxyl source. The Pd‐BNP catalyst has been reused up to five times. The heterogeneous test confirmed that the reaction is catalyzed by the heterogeneous Pd‐BNP catalyst.magnified image
Ordered Mesoporous TiO2 Gyroids: Effects of Pore Architecture and Nb‐Doping on Photocatalytic Hydrogen Evolution under UV and Visible Irradiation
Authors: Dörr Tobias Sebastian , Deilmann Leonie , Haselmann Greta , Cherevan Alexey , Zhang Peng , Blaha Peter , de Oliveira Peter William , Kraus Tobias , Eder Dominik 
Published: November 2018

AbstractPure and Nb‐doped TiO2 photocatalysts with highly ordered alternating gyroid architecture and well‐controllable mesopore size of 15 nm via co‐assembly of a poly(isoprene)‐block‐poly(styrene)‐block‐poly(ethylene oxide) block copolymer are synthesized. A combined effort by electron microscopy, X‐ray scattering, photoluminescence, X‐ray photoelectron spectroscopy, Raman spectroscopy, and density functional theory simulations reveals that the addition of small amounts of Nb results in the substitution of Ti4+ with isolated Nb5+ species that introduces inter‐bandgap states, while at high concentrations, Nb prefers to cluster forming shallow trap states within the conduction band minimum of TiO2. The gyroidal photocatalysts are remarkably active toward hydrogen evolution under UV and visible light due to the open 3D network, where large mesopores ensure efficient pore diffusion and high photon harvesting. The gyroids yield unprecedented high evolution rates beyond 1000 µmol h−1 (per 10 mg catalyst), outperforming even the benchmark P25‐TiO2 more than fivefold. Under UV light, the Nb‐doping reduces the activity due to the introduction of charge recombination centers, while the activity in the visible triple upon incorporation is owed to a more efficient absorption due to inter‐bandgap states. This unique pore architecture may further offer hitherto undiscovered optical benefits to photocatalysis, related to chiral and metamaterial‐like behavior, which will stimulate further studies focusing on novel light–matter interactions.
Propagation of Oscillating Chemical Signals through Reaction Networks
Authors: Roszak Rafał , Bajczyk Michał D. , Gajewska Ewa P. , Hołyst Robert , Grzybowski Bartosz A. 
Published: November 2018

AbstractAkin to electronic systems that can tune to and process signals of select frequencies, systems/networks of chemical reactions also “propagate” time‐varying concentration inputs in a frequency‐dependent manner. Whereas signals of low frequencies are transmitted, higher frequency inputs are dampened and converted into steady‐concentration outputs. Such behavior is observed in both idealized reaction chains as well as realistic signaling cascades, in the latter case explaining the experimentally observed responses of such cascades to input calcium oscillations. These and other results are supported by numerical simulations within the freely available Kinetix web application we developed to study chemical systems of arbitrary architectures, reaction kinetics, and boundary conditions.
Pyridyl Radical Cation for C−H Amination of Arenes
Authors: Rössler Simon L. , Jelier Benson J. , Tripet Pascal F. , Shemet Andrej , Jeschke Gunnar , Togni Antonio , Carreira Erick M. 
Published: November 2018

AbstractElectron‐transfer photocatalysis provides access to the elusive and unprecedented N‐pyridyl radical cation from selected N‐substituted pyridinium reagents. The resulting C(sp2)−H functionalization of (hetero)arenes furnishes versatile intermediates for the development of valuable aminated aryl scaffolds. Mechanistic studies that include the first spectroscopic evidence of a spin‐trapped N‐pyridyl radical adduct implicate SET‐triggered, pseudo‐mesolytic cleavage of the N−X pyridinium reagents mediated by visible light.
Sulfinate and Carbene Co‐catalyzed Rauhut–Currier Reaction for Enantioselective Access to Azepino[1,2‐a]indoles
Authors: Wu Xingxing , Zhou Liejin , Maiti Rakesh , Mou Chengli , Pan Lutai , Chi Yonggui Robin 
Published: November 2018

AbstractA carbene and sulfinate co‐catalyzed intermolecular Rauhut–Currier reaction between enals and nitrovinyl indoles is disclosed. The carbene catalyst activates the enal and the sulfinate co‐catalyst activates the nitrovinyl indole. Both activation processes are realized via the formation of covalent bonds between the catalysts and substrates to generate catalyst‐bound intermediates. The dual catalytic reaction affords azepino[1,2‐a]indole products with excellent stereoselectivity. Our study demonstrates the unique involvement of sulfinate as an effective nucleophilic catalyst in activating electron‐deficient alkenes for asymmetric reactions. This dual catalytic approach should also encourage future explorations of both sulfinate and carbene catalysts for new reactions.
Regulating Fast Anionic Redox for High‐Voltage Aqueous Hydrogen‐Ion‐based Energy Storage
Authors: Wang Shengping , Zhao Xiaoli , Yan Xiaojun , Xiao Ziwei , Liu Congcong , Zhang Yijie , Yang Xiaowei 
Published: November 2018

AbstractThe ionic conductivity and small size of the hydrogen ion make it an ideal charge carrier for hydrogen‐ion energy storage (HES); however, high‐voltage two‐electrode configurations are difficult to construct as the result of the lack of efficient cathodic energy storage. Herein, the high potential fast anionic redox at the cathode of reduced graphene oxide (rGO) was applied by introducing redox additive electrolytes. By coupling the storing hydrogen ion in the Ti3C2Tx at the anode, a HES with a voltage of 1.8 V and a plateau voltage at 1.2 V was constructed. Compared with 2.2 Wh kg−1 for the low‐voltage Ti3C2Tx//Ti3C2Tx, the specific energy of asymmetric rGO//Ti3C2Tx reaches 34.4 Wh kg−1. Furthermore, it possesses an energy density of 23.7 Wh kg−1 at high power density of 22.5 kW kg−1. Thus, this study provides a novel guideline for constructing high‐voltage fast HES full cells.
Light‐Addressable Ion Sensing for Real‐Time Monitoring of Extracellular Potassium
Authors: Yang Ying , Cuartero Maria , Gonçales Vinicius Romero , Gooding J. Justin , Bakker Eric 
Published: November 2018

AbstractWe report here on a light addressable potassium (K+) sensor where light illumination of a semiconducting silicon electrode substrate results in a localized activation of the faradaic electrochemistry at the illuminated spot. This allows one, by electrochemical control, to oxidize surface bound ferrocene moieties that in turn trigger K+ transfer from the overlaid K+‐selective film to the solution phase. The resulting voltammetric response is shown to be K+‐selective, where peak position is a direct function of K+ activity at the surface of electrode. This concept was used to measure extracellular K+ concentration changes by stimulating living breast cancer cells. The associated decrease of intracellular K+ level was confirmed with a fluorescent K+ indicator. In contrast to light addressable potentiometry, the approach introduced here relies on dynamic electrochemistry and may be performed in tandem with other electrochemical analysis when studying biological events on the electrode.
A Dual‐Targeted Organic Photothermal Agent for Enhanced Photothermal Therapy
Authors: Wang Hongyu , Chang Jinjie , Shi Mingwan , Pan Wei , Li Na , Tang Bo 
Published: November 2018

AbstractThe development of highly effective anticancer drugs that cause minimal damage to the surrounding normal tissues is a challenging topic in cancer therapy. Herein, we demonstrate a dual‐targeted organic molecule that functions as a photothermal agent by actively targeting tumor tissue and mitochondria to selectively kill cancer cells. The synthesized photothermal agent exhibited high photothermal conversion efficiency, low cytotoxicity, and good biological compatibility. In vivo experiments showed an excellent tumor inhibitory effect of the dual‐targeted photothermal agent.
Siliciumdioxidwachstum auf DNA‐Origamitemplaten durch Sol‐Gel‐Chemie
Authors: Nguyen Linh , Döblinger Markus , Liedl Tim , Heuer‐Jungemann Amelie 
Published: November 2018

AbstractDie Verbesserung der chemischen und mechanischen Stabilität von DNA‐Origamistrukturen auch unter Wärmeeinwirkung könnte die praktische Anwendung der DNA‐Nanotechnologie in den Materialwissenschaften ermöglichen. Um die Belastbarkeit von einzelnen DNA‐Origamiobjekten und 3D‐DNA‐Origamikristallen, sowohl in Lösung als auch im trockenen Zustand, zu erhöhen, kapseln wir im Sol‐Gel‐Verfahren DNA‐Origamistrukturen in eine schützende Siliciumdioxidschicht ein. So behalten alle Objekte ihre strukturelle Integrität, was eine detaillierte Strukturanalyse der Kristalle im trockenen Zustand ermöglicht. Ohne den trocknungsbedingten Kollaps und die damit verbundene Gitterdeformation lässt sich so die tatsächliche 3D‐Form der Gitter in Vakuum abbilden. Mithilfe energiedispersiver Röntgenspektroskopie können wir die gleichmäßige SiO2‐Beschichtung der DNA‐Strukturen nachweisen, wobei die Dicke der Beschichtung über die Konzentrationen der Reaktanten und über die Reaktionszeit gesteuert werden kann. Durch die Form‐“Transkription” von DNA‐Origami zu stabilen Siliciumdioxidstrukturen stellt unser biomimetischer Ansatz einen wichtigen Schritt in Richtung einer formgesteuerten Bottom‐up‐Synthese dar.
All‐Nanoporous Hybrid Membranes: Redefining Upper Limits on Molecular Separation Properties
Authors: Rashidi Fereshteh , Leisen Johannes , Kim Seok‐Jhin , Rownaghi Ali A. , Jones Christopher W. , Nair Sankar 
Published: November 2018

AbstractNew membrane‐based molecular separation processes are an essential part of the strategy for sustainable chemical production. A large literature on “hybrid” or “mixed‐matrix” membranes exists, in which nanoparticles of a higher‐performance porous material are dispersed in a polymeric matrix to boost performance. We demonstrate that the hybrid membrane concept can be redefined to achieve much higher performance if the membrane matrix and the dispersed phase are both nanoporous crystalline materials, with no polymeric phase. As the first example of such a system, we find that surface‐treated nanoparticles of the zeolite MFI can be incorporated in situ during growth of a polycrystalline membrane of the MOF ZIF‐8. The resulting all‐nanoporous hybrid membrane shows propylene/propane separation characteristics that exceed known upper‐bound performance limits defined for polymers, nanoporous materials, and polymer‐based hybrid membranes. This serves as a starting point for a new generation of chemical separation membranes containing interconnected nanoporous crystalline phases.
Affinity Enhancement of Protein Ligands by Reversible Covalent Modification of Neighboring Lysine Residues
Authors: Dal Corso Alberto , Catalano Marco , Schmid Anja , Scheuermann Jörg , Neri Dario 
Published: November 2018

AbstractThe discovery of protein ligands, capable of forming a reversible covalent bond with amino acid residues on a protein target of interest, may represent a general strategy for the discovery of potent small‐molecule inhibitors. We analyzed the ability of different aromatic aldehydes to form imines by reaction with lysine using 1H NMR techniques. 2‐Hydroxybenzaldehyde derivatives were found to efficiently form imines in the millimolar concentration range. These benzaldehyde derivatives could increase the binding affinity of protein ligands towards the cognate protein target. Affinity maturation was achieved not only by displaying ligand and aldehyde moieties on two complementary locked nucleic acid strands but also by incorporating the binding fragments in a single small‐molecule ligand. The affinity gain was only observed when lysine residues were accessible in the immediate surroundings of the ligand‐binding site and could be abrogated by quenching with a molar excess of hydroxylamine.
Total Internal Reflection‐Based Extinction Spectroscopy of Single Nanoparticles
Authors: Li Meng , Yuan Tinglian , Jiang Yingyan , Sun Linlin , Wei Wei , Chen Hong‐Yuan , Wang Wei 
Published: November 2018

AbstractHerein we report a reflection‐mode total internal reflection microscopy (TIRM) to measure the extinction spectrum of individual dielectric, plasmonic, or light‐absorbing nanoparticles, and to differentiate absorption and scattering components from the total optical output. These capabilities were enabled via illuminating the sample with evanescent wave of which the lightpath length was comparable with the size of single nanoparticles, leading to a dramatically improved reflectance change (ΔI/I0) up to tens of percent. It was further found that scattering and absorption of light contributed to bright and dark centroids, respectively, in the optical patterns of single nanoparticles, allowing to distinguish scattering and absorption components from the extinction spectrum by the use of an appropriate image processing method. In addition, wide‐field feature of TIRM enabled the studies on tens of nanoparticles simultaneously with gentle illumination.
DNA‐Origami‐Templated Silica Growth by Sol–Gel Chemistry
Authors: Nguyen Linh , Döblinger Markus , Liedl Tim , Heuer‐Jungemann Amelie 
Published: November 2018

AbstractImproving the stability of DNA origami structures with respect to thermal, chemical, and mechanical demands will be essential to fully explore the real‐life applicability of DNA nanotechnology. Here we present a strategy to increase the mechanical resilience of individual DNA origami objects and 3D DNA origami crystals in solution as well as in the dry state. By encapsulating DNA origami in a protective silica shell using sol–gel chemistry, all the objects maintain their structural integrity. This allowed for a detailed structural analysis of the crystals in a dry state, thereby revealing their true 3D shape without lattice deformation and drying‐induced collapse. Analysis by energy‐dispersive X‐ray spectroscopy showed a uniform silica coating whose thickness could be controlled through the precursor concentrations and reaction time. This strategy thus facilitates shape‐controlled bottom‐up synthesis of designable biomimetic silica structures through transcription from DNA origami.
Efficient Docking–Migration Strategy for Selective Radical Difluoromethylation of Alkenes
Authors: Yu Jiajia , Wu Zhen , Zhu Chen 
Published: November 2018

AbstractRadical‐mediated difunctionalization of alkenes is a powerful tactic for olefin utilization. However, the transformation of unactivated alkenes still remains a formidable challenge. Now a conceptually new docking–migration strategy is presented for the difunctionalization of alkenes with photoredox catalysis. Both activated and unactivated alkenes are suitable substrates. A vast array of functional groups are compatible with the mild reaction conditions. Heteroaryl and difluoromethyl are concomitantly incorporated into alkenes, leading to synthetically valuable products that are readily converted into a variety of fluorine‐containing molecules. The protocol provides a kinetic control of stereoselectivity for cycloalkenes to generate the unusual cis‐products, and offers an efficient approach for the late‐stage functionalization of complex natural products and drug molecules. A portfolio of dual‐function reagents are prepared for the elusive radical difunctionalization of alkenes.
Direct In Situ TEM Visualization and Insight into the Facet‐Dependent Sintering Behaviors of Gold on TiO2
Authors: Yuan Wentao , Zhang Dawei , Ou Yang , Fang Ke , Zhu Beien , Yang Hangsheng , Hansen Thomas W. , Wagner Jakob B. , Zhang Ze , Gao Yi , Wang Yong 
Published: November 2018

AbstractPreventing sintering of supported nanocatalysts is an important issue in nanocatalysis. A feasible way is to choose a suitable support. However, whether the metal–support interactions promote or prevent the sintering has not been fully identified. Now, completely different sintering behaviors of Au nanoparticles on distinct anatase TiO2 surfaces have been determined by in situ TEM. The full in situ sintering processes of Au nanoparticles were visualized on TiO2 (101) surface, which coupled the Ostwald ripening and particle migration coalescence. In contrast, no sintering of Au on TiO2 anatase (001) surface was observed under the same conditions. This facet‐dependent sintering mechanism is fully explained by the density function theory calculations. This work not only offers direct evidence of the important role of supports in the sintering process, but also provides insightful information for the design of sintering‐resistant nanocatalysts.