bluuebunny/crossref_metadata_2025 huggingface dataset:
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

An 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.

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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

Pure 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

Akin 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

Electron‐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

A 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

The 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

We 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

The 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

Die 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

New 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

The 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

Herein 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

Improving 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

Radical‐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

Preventing 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.
A liquid chromatography–tandem mass spectrometry method for preclinical pharmacokinetics and tissue distribution of hydrolyzable tannins chebulinic acid and chebulagic acid in rats
Authors: Lu Ying , Yan Huiyu , Teng Shiyong , Yang Xige
Published: November 2018

A simple and sensitive liquid chromatography–tandem mass spectrometry method was developed for the simultaneous determination of chebulinic acid and chebulagic acid in rat plasma and tissues and well used in the pharmacokinetic and tissue distribution studies after intraperitoneal injection administration. Samples were processed with methanol by protein precipitation, and chromatographic separation was performed on an Agilent Zorbax SB‐C18 column (50 × 2.1 mm, 1.8 μm) with a mobile phase consisting of methanol and water containing 0.1% formic acid (60:40, v/v). Quantification was performed by selected reaction monitoring with m/z 977.1 → 806.8 for chebulagic acid, m/z 979.0 → 808.7 for chebulinic acid and m/z 851.2 → 704.9 for the internal standard. Good linearity was observed over their respective concentration range. The pharmacokinetic study showed that both compounds reached their peak concentration values (605.8 ± 35.6 ng/mL for chebulinic acid and 1327.1 ± 118.6 ng/mL for chebulagic acid) at the same time of 0.9 h following intraperitoneal injection administration. The two compounds could be detected in blood‐abundant tissues. The kidney had the highest concentrations (462.6 ± 138.5 ng/g for chebulinic acid and 1651.7 ± 167.7 ng/g for chebulagic acid) at 1 h post‐dose, followed by the heart, liver, spleen and lung.
Exfoliated NiFe Layered Double Hydroxide Cocatalyst for Enhanced Photoelectrochemical Water Oxidation with Hematite Photoanode
Authors: Park Yoon Bin , Kim Ju Hun , Jang Youn Jeong , Lee Jin Ho , Lee Min Hee , Lee Byeong Jun , Youn Duck Hyun , Lee Jae Sung
Published: November 2018

In photoelectrochemical (PEC) water oxidation, a low onset potential and a high photocurrent are desired and a cocatalyst on the photoanode could improve the performance. For better use of a NiFe layered double hydroxide (LDH) cocatalyst, concept of exfoliation is applied. Exfoliation gives higher electrochemical surface area and better water oxidation kinetics, which is reflected in improved charge injection efficiency at low bias potentials. Exfoliated NiFe LDH shows increased photocurrent density by 50 % at 1.0 VRHE and reduced onset potential by 140 mV relative to those of stacked bulk LDH under 1 sun illumination, making it a much more effective cocatalyst for α‐Fe2O3 photoanode. The intensity modulated photocurrent spectroscopy shows that the improved photocurrents and early onset potentials of exfLDH/α‐Fe2O3 photoanode are attributed to fast charge transfer and, more importantly, suppressed charge recombination due to passivation of α‐Fe2O3 surface by the LDH monolayer sheet.
Crystallization of Sodium Salt of Organic Acid as Example for Neutral Salt Recovery of Bio Acids
Authors: Plate Hermann , van Esch Jan
Published: November 2018

The optimization of an organic acid production process downstream of fermentation is presented. Sodium salt solution of the organic acid (Na salt) solution is the product in the industrial fermentation process for the organic acid production and until today, it has not been attempted to directly crystallize/isolate the Na salt under these circumstances. Evaporation crystallization of Na salt directly from the solid‐free fermentation broth without purification can be realized with high product purity. Parameters limiting the crystallization/separation process are identified and discussed. The above points are considered as a function of viscosity, crystal size, and product purity. Comparison with the existing process completes this evaluation. The impact on the process design and alternatives are illustrated. The modification of hybrid processes using crystallization also as a purification step is investigated.
Beware of r2 even for test datasets: Using the latest measured y‐values (r2LM) in time series data analysis
Authors: Kaneko Hiromasa
Published: November 2018

The determination coefficient of a test dataset, r2, is calculated and used to compare the performance of adaptive soft sensors and discuss the possibility of their practical use. However, soft sensors that give very high r2 values do not always have sufficient predictive accuracy for use in process control. Therefore, a new measure for soft sensors based on the latest measured y‐values (r2LM) is proposed. This metric can be used in time series data analysis to determine whether the variations in y‐values estimated by soft sensors come from variations in the input variables or those of the latest measured y‐values. Through case studies using real and simulated datasets, it is confirmed that low r2LM values correspond to meaningless soft sensors, even when their r2 value is high, and that high r2LM values imply that the estimation results are useful for process control with soft sensors. Python and MATLAB codes for computing r2LM can be downloaded from GitHub: https://github.com/hkaneko1985/r2lm.
Self‐Healing Polymer Electrolytes Formed via Dual‐Networks: A New Strategy for Flexible Lithium Metal Batteries
Authors: Zhou Binghua , Zuo Cai , Xiao Zhuliu , Zhou Xingping , He Dan , Xie Xiaolin , Xue Zhigang
Published: November 2018

A novel polymer electrolyte with mechanically robust and self‐healing properties was fabricated through a dual‐network structure, crosslinked by quadruple hydrogen bonding and chemical bonding. The dynamic ureido‐pyrimidinone (UPy) dimers were the first network in the polymer matrix. This group endows the polymer electrolyte with good self‐healing capacity and improves the reliability and lifetime of the polymer lithium batteries. The crosslinked polyethylene glycol‐bis‐carbamate dimethacrylate (PEGBCDMA) is the second network and guarantees dimensional stability and good mechanical properties of the polymer electrolyte. The dual‐network self‐healing polymer electrolyte (DN‐SHPE) exhibits improved ionic conductivity versus the polymer electrolyte fabricated by poly(ethylene glycol) diacrylate (PEGDA). It has high thermal stability (up to 350 °C) and excellent interfacial stability with the electrodes. When the DN‐SHPE‐based cells were fabricated with LiFePO4 and Li metal, the resulting cells show good reversible specific capacity and considerable rate capability. Moreover, the pouch cell could maintain electrochemical function even under deformation or folding conditions.
Total Synthesis of Callyspongiolide, Part 2: The Ynoate Metathesis/cis‐Reduction Strategy
Authors: Wölfl Bernhard , Mata Guillaume , Fürstner Alois
Published: November 2018

The macrocyclic core of the cytotoxic marine natural product callyspongiolide (1) was forged by ring‐closing alkyne metathesis (RCAM) of an ynoate precursor using a molybdenum alkylidyne complex endowed with triarylsilanolate ligands as the catalyst. This result is remarkable in view of the failed attempts documented in the literature at converting electron deficient alkynes with the aid of more classical catalysts. The subsequent Z‐selective semi‐reduction of the resulting cycloalkyne by hydrogenation over nickel boride required careful optimization in order to minimize overreduction and competing dehalogenation of the compound's alkenyl iodide terminus as needed for final attachment of the side chain of 1 by Sonogashira coupling. The required cyclization precursor itself was prepared via Kocienski olefination.
Dehalogenation of Halogenated Nucleobases and Nucleosides by Organoselenium Compounds
Authors: Mondal Santanu , Mugesh Govindasamy
Published: November 2018

Halogenated nucleosides, such as 5‐iodo‐2′‐deoxyuridine and 5‐iodo‐2′‐deoxycytidine, are incorporated into the DNA of replicating cells to facilitate DNA single‐strand breaks and intra‐ or interstrand crosslinks upon UV irradiation. In this work, it is shown that the naphthyl‐based organoselenium compounds can mediate the dehalogenation of halogenated pyrimidine‐based nucleosides, such as 5‐X‐2′‐deoxyuridine and 5‐X‐2′‐deoxycytidine (X=Br or I). The rate of deiodination was found to be significantly higher than that of the debromination for both nucleosides. Furthermore, the deiodination of iodo‐cytidines was found to be faster than that of iodo‐uridines. The initial rates of the deiodinations of 5‐iodocytosine and 5‐iodouracil indicated that the nature of the sugar moiety influences the kinetics of the deiodination. For both the nucleobases and nucleosides, the deiodination and debromination reactions follow a halogen‐bond‐mediated and addition/elimination pathway, respectively.
Synthesis of Bis(phosphanyl)alkane Monosulfides by the Addition of Diphosphane Monosulfides to Alkenes under Light
Authors: Sato Yuki , Kawaguchi Shin‐ichi , Nomoto Akihiro , Ogawa Akiya
Published: November 2018

Bis‐phosphanated compounds are regarded as the most ubiquitous privileged ligand structures in transition‐metal catalysis. The development of highly atom economical reactions is of great importance for their syntheses because less atom economical methods often require complicated purification procedures under inert atmospheres to remove excess starting materials and byproducts. Herein, the photoinduced addition reactions of diphosphane monosulfides bearing PV(S)−PIII single bonds to alkenes is disclosed. These reactions require only equimolar amounts of the diphosphane monosulfide relative to the alkene and facilitate highly selective introduction of two different types of phosphorus‐containing groups, such as thiophosphoryl and phosphanyl groups, into a variety of alkenes without any catalyst, base, or additive.
Robust Icephobic Performance of Flexible Needles
Authors: Liu Xuejuan , Zhao Hongbin , Li Peiliu , Pang Yan , Fan Yuzun , Zhang Bo , Wang Lei , Zheng Yongmei , Wang Zuankai
Published: November 2018

Superhydrophobic micro‐/nanopatterned structures exhibit robust water/ice repellence in harsh environments, which is significant for theoretical study and industrial applications such as cooling in nuclear power, heat transfer, and self‐cleaning for aircraft. However, the reported studies regarding icephobic functional surfaces based on rigid materials have indicated potential dangers in applications, e. g., the roughness topographies are easily ruined in the icing process, which limits further application and study. In this study, polydimethylsiloxane‐based flexible microneedles (FNs) with ZnO nanorods are designed and fabricated and further characterized with robust icephobicity at a temperature of 0 °C. In this system, the flexible microneedles could bend to match the deformation caused by icing from condensed droplets, resulting in protecting the nanorods on its surface, which is significantly promising for durable icephobicity in harsh environments.
t‐Si64: A Novel Silicon Allotrope
Authors: Fan Qingyang , Niu Rui , Zhang Wenzhu , Zhang Wei , Ding Yingchun , Yun Sining
Published: November 2018

Utilizing first principle calculations, a novel Si64 silicon allotrope in the I41/amd space group with tetragonal symmetry (denoted as t‐Si64 below) is proposed in this work. In addition, also its structural, anisotropic mechanical, and electronic properties along with its minimum thermal conductivity κmin were predicted. The mechanical and thermodynamic stability of t‐Si64 were evaluated by means of elastic constants and phonon spectra. The electronic band structure indicates that t‐Si64 is an indirect band gap semiconductor with a band gap: 0.67 eV (primitive cell) compared to a direct band gap of 0.70 eV with respect to a conventional cell. The minimum thermal conductivity of t‐Si64 (0.74 W cm−1 K−1) is much smaller than that of diamond silicon (1.13 W cm−1 K−1). Therefore, Si−Ge alloys in the I41/amd space group are potential thermoelectric materials.
Anabaena sp. strain PCC 7120: Laboratory Maintenance, Cultivation, and Heterocyst Induction
Authors: Videau Patrick , Cozy Loralyn M.
Published: November 2018

Anabaena sp. strain PCC 7120 is a multicellular, filamentous, freshwater cyanobacterium that is capable of differentiating specialized heterocyst cells for nitrogen fixation. This unit includes protocols for the growth and maintenance of Anabaena appropriate for a research or teaching laboratory. Controlled induction and assessment of heterocyst development is also covered. © 2018 by John Wiley & Sons, Inc.
Integrated potentiostat for detection of Chagas disease
Authors: Agis Leonardo , Torres Fabián , Gak Joel , Miguez Matías
Published: November 2018

The design of a low‐power‐integrated potentiostat that measures electric current intended for a Chagas disease detection application is presented. This circuit can generate and measure currents from 1 to 10 μA with a relative error under 5%. The remaining part of the circuit consumes only 1.5 μA. The circuit was designed using the 0.6 μm XC06 technology from the X‐FAB, with a total silicon area of 0.24 mm2 (without pads).
Analysis and design of joint CFO/channel estimate techniques for a cooperative STBC‐OFDM system
Authors: Lin Tsui‐Tsai , Hwang Fuh‐Hsin
Published: November 2018

This paper studies the joint estimation technique of carrier frequency offset (CFO) and channel information for a distributed decode‐and‐forward (DF) cooperative space‐time block‐coded (STBC) orthogonal frequency division multiplexing (OFDM) system. For the considered relay system, we provide theoretical analysis of the effects upon the output signal‐to‐noise ratio (SNR), which is caused by the CFO/channel estimation error. Based on the provided analytical results, a joint CFO/channel estimation scheme is then developed, where the CFO estimate is achieved by a multiple‐dimensional linear search algorithm. Furthermore, we propose an alternative estimation solution with iteration approach being designed for the CFO estimation prior to the channel estimation. In contrast to the former estimator, the iterative method enjoys the advantage of the substantially reduced implementation complexity without sacrificing the estimate performance. The conducted computer simulation results verify the effectiveness of the proposed schemes.
Genetic and chemical divergence among host races of a socially parasitic ant
Authors: Torres Candice W. , Tonione Maria A. , Ramírez Santiago R. , Sapp Joseph R. , Tsutsui Neil D.
Published: November 2018

Host–parasite associations facilitate the action of reciprocal selection and can drive rapid evolutionary change. When multiple host species are available to a single parasite, parallel specialization on different hosts may promote the action of diversifying natural selection and divergence via host race formation. Here, we examine a population of the kidnapper ant (Polyergus mexicanus) that is an obligate social parasite of three sympatric ant species: Formica accreta, F. argentea, and F. subaenescens (formerly F. fusca). Behavioral and ecological observations of P. mexicanus have shown that individual colonies parasitize only one species of host and that new Polyergus queens maintain host fidelity when establishing new colonies. To successfully adapt to a particular host, Polyergus ants may mimic or camouflage themselves with the species‐specific chemical cues (cuticular hydrocarbons) that their hosts use to ascertain colony membership. To investigate the extent of host specialization, we collected both genetic and chemical data from P. mexicanus that parasitize each of the three different Formica species in sympatry. We show that host‐associated genetic structure exists for both maternally inherited mitochondrial DNA data and biparentally inherited microsatellite markers. We also show that P. mexicanus can be distinguished by chemical profile according to host due to partial matching with their host. Our results support the hypothesis that host race formation is occurring among lineages of P. mexicanus that use different Formica hosts. Thus, this system may represent a promising model for illuminating the early steps of divergence, accumulation of reproductive isolation, and speciation.
Response of soil organic carbon to vegetation degradation along a moisture gradient in a wet meadow on the Qinghai–Tibet Plateau
Authors: Alhassan Abdul‐Rauf Malimanga , Ma Weiwei , Li Guang , Jiang Zhirong , Wu Jiangqi , Chen Guopeng
Published: November 2018

The study was conducted during the growing seasons of 2013, 2014, and 2015 in the wet meadows on the eastern Qinghai–Tibet plateau (QTP) in the Gansu Gahai Wetland Nature Reserve to determine the dynamics of soil organic carbon (SOC) as affected by vegetation degradation along a moisture gradient and to assess its relationship with other soil properties and biomass yield. Hence, we measured SOC at depths of 0–10, 10–20, and 20–40 cm under the influence of four categories of vegetation degradation (healthy vegetation [HV], slightly degraded [SD], moderately degraded [MD], and heavily degraded [HD]). Our results showed that SOC decreased with increased degree of vegetation degradation. Average SOC content ranged between 36.18 ± 4.06 g/kg in HD and 69.86 ± 21.78 g/kg in HV. Compared with HV, SOC content reduced by 30.49%, 42.22%, and 48.22% in SD, MD, and HD, respectively. SOC significantly correlated positively with soil water content, aboveground biomass, and belowground biomass, but significantly correlated negatively with soil temperature and bulk density (p < 0.05). Highly Significant positive correlations were also found between SOC and total nitrogen (p = 0.0036), total phosphorus (p = 0.0006) and total potassium (p < 0.0001). Our study suggests that severe vegetation and moisture loss led to approximately 50% loss in SOC content in the wet meadows, implying that under climate warming, vegetation and soil moisture loss will dramatically destabilize carbon sink capacities of wetlands. We therefore suggest wetland hydrological management, restoration of vegetation, plant species protection, regulation of grazing activities, and other anthropogenic activities to stabilize carbon sink capacities of wetlands.
Synergistically Suppressing Lithium Dendrite Growth by Coating Poly‐l‐Lactic Acid on Sustainable Gel Polymer Electrolyte
Authors: Li Lei , Yu Miao , Wang Feijun , Zhang Xinfang , Shao Ziqiang
Published: November 2018

Lithium (Li) metal batteries are promising candidates in next‐generation high‐power energy storage devices. However, Li dendrite growth induces great safety issues. Herein, inspired by the high electrolyte uptake, high polarity of the cellulose derivative, and excellent mechanical properties of poly‐l‐lactic acid (PLLA), a sustainable multifunctional gel polymer electrolyte (GPE) through coating a thin PLLA film on the natural polymer is proposed for Li dendrite suppression and cycling stability improvement. In addition, PLLA film coating can also enhance the thermal stability and interfacial interaction between the PLLA‐coated GPEs and Li metal, thus improving the safety of the batteries. Due to these unique beneficial features, the green GPEs enable stable cycling of the Li metal anode with an enhanced Li+ transference number and coulombic efficiency during extended cycles and increases the lifetime by inhibiting short‐circuit failures even under a high energy density and extensive Li metal deposition.
Seismic response of bridge piers on pile groups for different soil damping models and lumped parameter representations of the foundation
Authors: González Francisco , Padrón Luis A. , Carbonari Sandro , Morici Michele , Aznárez Juan J. , Dezi Francesca , Leoni Graziano
Published: November 2018

This paper presents a wide parametric study aimed at elucidating the influence, on the computed seismic response of bridge piers, of two related aspects of the model: (1) the adoption of the classical hysteretic or the causal Biot's damping models for the soil and (2) the use of two different lumped parameter models of different complexity and accuracy to approximate the impedances of the pile foundation. A total of 2072 cases, including different superstructures, pile foundations, soil deposits, and seismic input signals, are studied. The results are presented so that the influence of the different parameters involved in the analysis can be assessed. From an engineering point of view, both lumped parameter models provide, in general, sufficiently low errors. The choice of the most adequate model for each case will depend not only on the configuration of the structure and the soil‐foundation system but also on the assumed soil damping model, whose influence on the computed seismic responses is relevant in many cases. The nonphysical behaviour provided by the classical hysteretic damping model for the soil at zero frequency generates issues in the process of fitting the impedance functions. It is also found that larger deck displacements are predicted by Biot's model due to the higher damping at low frequencies provided by the classical hysteretic damping model.
Do hedge funds time market tail risk? Evidence from option‐implied tail risk
Authors: Shin Jung‐Soon , Kim Minki , Oh Dongjun , Kim Tong Suk
Published: November 2018

This paper focuses on an unexplored dimension of fund managers’ timing ability: Market‐wide tail risk implied by information in options markets. Constructing the option‐implied tail risk, we investigate whether hedge fund managers can strategically time the tail risk through adjusting their exposure to changes of it. Using an extensive sample of equity‐oriented hedge funds, we find strong evidence of tail risk timing ability of hedge fund managers. Furthermore, tail risk timing ability brings significant economic value to investors. Top‐ranked funds outperform bottom‐ranked funds by 5–7% annually after adjusting for risk factors. Our results are robust to various robustness checks.
Long‐term dynamics of the VIX index and its tradable counterpart VXX
Authors: Bašta Milan , Molnár Peter
Published: November 2018

We study the relationship of the VIX index and the exchange‐traded note VXX on various timescales. We find that changes of VIX and VXX are correlated only contemporaneously on timescales of days, but VIX leads VXX on timescales of months. Next, we construct a simple joint model for VXX and VIX which replicates all the key characteristics of these two time series, but in which VIX and VXX are related only via a correlated error term. Therefore, VIX cannot be used as a predictor of VXX and there is no apparent trading profit opportunity.
Detrital zircon U–Pb ages from the Middle to Late Permian strata of the Yiyang area, southern North China Craton: Implications for the Mianlue oceanic crust subduction
Authors: Wang Yanpeng , Yang Wentao , Zheng Deshun , Zuo Pengfei , Qi Shuaishuai
Published: November 2018

Basin formation and sedimentary development in the southern North China Craton (NCC) are closely related to the tectonic evolution of the Qinling Orogenic Belt (QOB). With the aim of revealing the coupling evolution between the QOB and southern NCC during the Late Palaeozoic, an investigation based on provenance analysis was performed in this study. We present new detrital zircon U–Pb data from the Middle–Late Permian sediments in the Yiyang area, southern NCC. The results show that detrital zircons, from the Middle Permian Shihezi Formation, have three major peaks at 2,447, 1,905, and 296 Ma. In contrast, the lower and upper parts of the Late Permian Sunjiagou Formation yield major peaks at ~1.85 Ga and ~260 Ma, with weak peaks at ~2.5 Ga, ~450 Ma, and ~315 Ma, and the middle part of the Sunjiagou Formation displays a major peak at 429 Ma. Combined with published palaeocurrent data and lithofacies palaeogeography, the sediments of the Middle Permian Shihezi Formation were sourced from the Inner Mongolia Palaeo‐Uplift along the northern margin of the NCC, whereas the Upper Permian Sunjiagou Formation originated mainly from the southern margin of the NCC including the North Qinling Belt. This provenance shift indicates that the North Qinling Belt and southern margin of the NCC initiated the uplift and exhumation during the Late Permian. On the basis of the evolutionary history of the QOB, we attribute the uplift geodynamics to the Mianlue oceanic crust subduction. This study provides important sedimentological constraints for the tectonic conversion during the Late Palaeozoic along the southern margin of the NCC, which also restricts the start‐up time of the Mianlue oceanic crust subduction from the perspective of the basin–mountain system.
Your love makes me feel more secure: Boosting attachment security decreases materialistic values
Authors: Sun Ying , Wang Luxiao , Jiang Jiang , Wang Rong
Published: November 2018

Enhanced interpersonal security has been shown to diminish the desire for money and possessions. In the present study, we focus on attachment security to examine the relationship between attachment security and materialism. By employing the experience in close relationships – short scale and material values scale, we observed a positive relationship between attachment insecurity and materialism in Study 1. In Study 2, we primed participants' feeling of attachment security to further explore the impact of attachment security on materialistic values. The results showed that participants in the security‐priming group exhibited lower levels of state materialism (Study 2a) and a longer time to respond to materialism‐related words (Studies 2b and 2c) than participants in the neutral condition. However, attachment styles did not moderate the attachment security‐materialism relationship. Our findings reveal that regardless of attachment style, boosting attachment security can effectively decrease materialism.
IL-17 Receptor Signaling in Osteoblasts/Osteocytes Mediates PTH-Induced Bone Loss and Enhances Osteocytic RANKL Production
Authors: Li Jau-Yi , Yu Mingcan , Tyagi Abdul Malik , Vaccaro Chiara , Hsu Emory , Adams Jonathan , Bellido Teresita , Weitzmann M Neale , Pacifici Roberto
Published: November 2018

Primary hyperparathyroidism (PHPT) is a condition where elevated PTH levels lead to bone loss, in part through increased production of the osteoclastogenic factor IL-17A, by bone marrow (BM) T-helper 17 (Th17) cells, a subset of helper CD4+ T cells. In animals, PHPT is modeled by continuous PTH treatment (cPTH). In mice, an additional critical action of cPTH is the capacity to increase the production of RANKL by osteocytes. However, a definitive link between IL-17A and osteocytic expression of RANKL has not been made. Here we show that cPTH fails to induce cortical and trabecular bone loss and causes less intense bone resorption in conditional knock-out (IL-17RAΔOCY) male and female mice lacking the expression of IL-17A receptor (IL-17RA) in dentin matrix protein 1 (DMP1)-8kb-Cre–expressing cells, which include osteocytes and some osteoblasts. Therefore, direct IL-17RA signaling in osteoblasts/osteocytes is required for cPTH to exert its bone catabolic effects. In addition, in vivo, silencing of IL-17RA signaling in in DMP1-8kb–expressing cells blunts the capacity of cPTH to stimulate osteocytic RANKL production, indicating that cPTH augments osteocytic RANKL expression indirectly, via an IL-17A/IL-17RA–mediated mechanism. Thus, osteocytic production of RANKL and T cell production of IL-17A are both critical for the bone catabolic activity of cPTH. © 2018 American Society for Bone and Mineral Research.
Structural features of cross‐sectional wing bones in the griffon vulture (Gyps fulvus)as a prediction of flight style
Authors: Frongia Gian N. , Muzzeddu Marco , Mereu Paolo , Leoni Giovanni , Berlinguer Fiammetta , Zedda Marco , Farina Vittorio , Satta Valentina , Di Stefano Marco , Naitana Salvatore
Published: November 2018

Flight is an energetically costly form of transport imparting biomechanical stress that acts upon the wing bones. Previous studies have suggested that the cross‐sectional and microstructural features of wing bones may be adapted to resist biomechanical loads. During flight, however, each wing bone potentially experiences a unique loading regime. To assess possible differences among wing bones, we analyzed the microstructural features of the humerus, radius, ulna, and carpometacarpus (CMC) in eight griffon vultures (Gyps fulvus). Vascular canal orientation was evaluated in the diaphysis of the wing bones. Laminarity index (LI) was significantly different in the humerus versus CMC and ulna versus CMC. Results showed a lower proportion of circular vascular canals, due to resistance to torsional loads, in CMC than in humerus and ulna. The midshaft cross‐section revealed an elliptical shape in the CMC compared to the circular shape observed in the other wing bones, with a maximum second moment of inertia (Imax) orientation which suggests a capacity to withstand bending loads in a dorsoventral direction. The volumetric bone mineral density in the diaphysis was statistically different in CMC compared to the other bones analyzed. Its lower mineral density may reflect an adaptation to a different type and load of stresses in CMC compared to the proximal wing bones. No significant difference was found in the relative cortical area (CA/TA) among the four elements, while the polar moment of area J (Length‐standardized) revealed a higher resistance to torsional load in the humerus than in the other bones. Our results would seem to indicate that griffon wing bones are structured as an adaptation, represented by two segments that respond to force in two ways: the proximal segment is specially adapted to resist torsional loads, whereas the distal one is adapted to resist bending loads.