bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoscale Bubble Domains and Topological Transitions in Ultrathin Ferroelectric Films
Authors: Zhang Qi , Xie Lin , Liu Guangqing , Prokhorenko Sergei , Nahas Yousra , Pan Xiaoqing , Bellaiche Laurent , Gruverman Alexei , Valanoor Nagarajan 
Published: October 2017

AbstractObservation of a new type of nanoscale ferroelectric domains, termed as “bubble domains”—laterally confined spheroids of sub‐10 nm size with local dipoles self‐aligned in a direction opposite to the macroscopic polarization of a surrounding ferroelectric matrix—is reported. The bubble domains appear in ultrathin epitaxial PbZr0.2Ti0.8O3/SrTiO3/PbZr0.2Ti0.8O3 ferroelectric sandwich structures due to the interplay between charge and lattice degrees of freedom. The existence of the bubble domains is revealed by high‐resolution piezoresponse force microscopy (PFM), and is corroborated by aberration‐corrected atomic‐resolution scanning transmission electron microscopy mapping of the polarization displacements. An incommensurate phase and symmetry breaking is found within these domains resulting in local polarization rotation and hence impart a mixed Néel–Bloch‐like character to the bubble domain walls. PFM hysteresis loops for the bubble domains reveal that they undergo an irreversible phase transition to cylindrical domains under the electric field, accompanied by a transient rise in the electromechanical response. The observations are in agreement with ab‐initio‐based calculations, which reveal a very narrow window of electrical and elastic parameters that allow the existence of bubble domains. The findings highlight the richness of polar topologies possible in ultrathin ferroelectric structures and bring forward the prospect of emergent functionalities due to topological transitions.
Spin‐1 Bose Hubbard Model with Nearest Neighbour Extended Interaction
Authors: Nabi Sk Noor , Basu Saurabh 
Published: October 2017

AbstractA spinor () Bose gas is studied in presence of a density‐density interaction through a mean field approach and a perturbation theory for either sign of the spin dependent interaction, namely the antiferromagnetic (AF) and the ferromagnetic cases. In the AF case, the charge density wave (CDW) phase appears to be sandwiched between the Mott insulating (MI) and the supersolid phases for small values of the extended interaction strength. But the CDW phase completely occupies the MI lobe when the extended interaction strength is larger than a certain critical value related to the width of the MI lobes and hence opens up the possibilities of spin singlet and nematic CDW insulating phases. In the ferromagnetic case, the phase diagram shows similar features as that of the AF case and are in complete agreement with a spin‐0 Bose gas. The perturbation expansion calculations nicely corroborate the mean field phase results in both these cases. Further, we extend our calculations in presence of a harmonic confinement and obtained the momentum distribution profile that is related to the absorption spectra in order to distinguish between different phases.
Mangankomplexe in der (De)Hydrier‐Katalyse – ein Vergleich mit Cobalt‐ und Eisenkatalysatoren
Authors: Kallmeier Fabian , Kempe Rhett 
Published: October 2017

AbstractDer nachhaltige Umgang mit den Ressourcen unseres Planeten ist essenziell. Edelmetalle sind sehr selten und werden vielfältig in Schlüsseltechnologien wie der Katalyse genutzt. Mangan ist das dritthäufigste Übergangsmetall der Erdkruste und aufgrund seiner kürzlich entdeckten beeindruckenden Reaktivität für Hydrierungen und Dehydrierungen ein potenzieller Edelmetall‐“Ersatz”. An einen derartigen “Ersatz” sind auch Hoffnungen auf neuartige Selektivitätsprofile geknüpft, die mit Edelmetallen nicht erzielt werden können. Dass Mangankomplexe eine solche Reaktivität für (De)Hydrierungen aufweisen, wurde erstmals 2016 gezeigt. Hier fassen wir die seitdem publizierten Arbeiten auf diesem Gebiet zusammen und diskutieren im Besonderen die Bedeutung der Mangankatalysatoren im Vergleich zu Cobalt‐ und Eisenkatalysatoren.
Localized Supramolecular Peptide Self‐Assembly Directed by Enzyme‐Induced Proton Gradients
Authors: Rodon Fores Jennifer , Martinez Mendez Miguel Leonardo , Mao Xiyu , Wagner Déborah , Schmutz Marc , Rabineau Morgane , Lavalle Philippe , Schaaf Pierre , Boulmedais Fouzia , Jierry Loïc 
Published: October 2017

AbstractElectrodes are ideal substrates for surface localized self‐assembly processes. Spatiotemporal control over such processes is generally directed through the release of ions generated by redox reactions occurring specifically at the electrode. The so‐used gradients of ions proved their effectiveness over the last decade but are in essence limited to material‐based electrodes, considerably reducing the scope of applications. Herein is described a strategy to enzymatically generate proton gradients from non‐conductive surfaces. In the presence of oxygen, immobilization of glucose oxidase (GOx) on a multilayer film provides a flow of protons through enzymatic oxidation of glucose by GOx. The confined acidic environment located at the solid–liquid interface allows the self‐assembly of Fmoc‐AA‐OH (Fmoc=fluorenylmethyloxycarbonyl and A=alanine) dipeptides into β‐sheet nanofibers exclusively from and near the surface. In the absence of oxygen, a multilayer nanoreactor containing GOx and horseradish peroxidase (HRP) similarly induces Fmoc‐AA‐OH self‐assembly.
Diastereoselective Construction of Densely Functionalized 1‐Halocyclopentenes Using an Alkynyl Halo‐Prins/Halo‐Nazarov Cyclization Strategy
Authors: Alachouzos Georgios , Frontier Alison J. 
Published: October 2017

AbstractA diastereoselective two‐step strategy for the synthesis of densely functionalized 1‐halocyclopentenes with several chiral centers has been developed. In the first step, a multicomponent alkynyl halo‐Prins reaction joins an enyne, a carbonyl derivative, and either a chloride, bromide, or iodide to produce a cyclic ether intermediate. In the subsequent step, the intermediate is ionized to generate a halopentadienyl cation, which undergoes an interrupted halo‐Nazarov cyclization. The products contain three new contiguous stereogenic centers, generated with a high level of stereocontrol, as well as a vinyl halide allowing for additional functionalization. The strategy creates two new carbon–carbon bonds, one carbon–halide bond, and one carbon–oxygen bond.
Access to Chiral Hydropyrimidines through Palladium‐Catalyzed Asymmetric Allylic C−H Amination
Authors: Wang Pu‐Sheng , Shen Meng‐Lan , Wang Tian‐Ci , Lin Hua‐Chen , Gong Liu‐Zhu 
Published: October 2017

AbstractA palladium‐catalyzed asymmetric intramolecular allylic C−H amination controlled by a chiral phosphoramidite ligand was established for the preparation of various substituted chiral hydropyrimidinones, the precursors of hydropyrimidines, in high yields with high enantioselectivities. In particular, dienyl sodium N‐sulfonyl amides bearing an arylethene‐1‐sulfonyl group underwent a sequential allylic C−H amination and intramolecular Diels–Alder (IMDA) reaction to produce chiral fused tricyclic tetrahydropyrimidinone frameworks in high yields and with high levels of stereoselectivity. Significantly, this method was used as the key step in an asymmetric synthesis of letermovir.
Atomically Dispersed Copper–Platinum Dual Sites Alloyed with Palladium Nanorings Catalyze the Hydrogen Evolution Reaction
Authors: Chao Tingting , Luo Xuan , Chen Wenxing , Jiang Bin , Ge Jingjie , Lin Yue , Wu Geng , Wang Xiaoqian , Hu Yanmin , Zhuang Zhongbin , Wu Yuen , Hong Xun , Li Yadong 
Published: October 2017

AbstractDesigning highly active catalysts at an atomic scale is required to drive the hydrogen evolution reaction (HER). Copper–platinum (Cu‐Pt) dual sites were alloyed with palladium nanorings (Pd NRs) containing 1.5 atom % Pt, using atomically dispersed Cu on ultrathin Pd NRs as seeds. The ultrafine structure of atomically dispersed Cu‐Pt dual sites was confirmed with X‐ray absorption fine structure (XAFS) measurements. The Pd/Cu‐Pt NRs exhibit excellent HER properties in acidic solution with an overpotential of only 22.8 mV at a current density of 10 mA cm−2 and a high mass current density of 3002 A g−1(Pd+Pt) at a −0.05 V potential.
Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine‐Functionalized Metal–Organic Frameworks
Authors: Li Xinle , Zhang Biying , Tang Linlin , Goh Tian Wei , Qi Shuyan , Volkov Alexander , Pei Yuchen , Qi Zhiyuan , Tsung Chia‐Kuang , Stanley Levi , Huang Wenyu 
Published: October 2017

AbstractNitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine‐functionalized Zr metal–organic framework (MOF), UiO‐66‐NH2 (Pt@UiO‐66‐NH2) as a multifunctional catalyst in the one‐pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO‐66‐NH2, Pt@UiO‐66‐NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO‐66, and Pd@UiO‐66‐NH2. Pt@UiO‐66‐NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO‐66‐NH2). To our knowledge, this work demonstrates the first examples of one‐pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
Intramolecular Thioether Migration in the Rhodium‐Catalyzed Ene‐Cycloisomerization of Alkenylidenecyclopropanes by a Metal‐Mediated β‐Sulfide Elimination
Authors: Su Yu , Inglesby Phillip A. , Evans P. Andrew 
Published: October 2017

AbstractReported is the first example of a rhodium‐mediated β‐sulfide elimination, which represents a new mode of reactivity for late‐transition‐metal chemistry. This serendipitous discovery facilitates an ene‐cycloisomerization of allylic‐sulfide‐containing alkenylidenecyclopropanes (ACPs) to afford five‐membered carbo‐ and heterocyclic rings with concomitant intramolecular thioether migration. Interestingly, similar selectivity is obtained with both E‐ and Z‐allylic sulfides and the reaction is also feasible with an allylic selenide. Mechanistic studies are consistent with an inner‐sphere transfer of the sulfide, which is remarkable given the propensity for sulfides to poison transition‐metal catalysts. Finally, this type of atom‐economical rearrangement is envisioned to prompt the development of related processes given the utility of sulfides in target‐directed synthesis.
Bifurcated Nickel‐Catalyzed Functionalizations: Heteroarene C−H Activation with Allenes
Authors: Nakanowatari Sachiyo , Müller Thomas , Oliveira João C. A. , Ackermann Lutz 
Published: October 2017

AbstractA unified strategy for nickel(0)‐catalyzed C−H allylations, alkenylations, and dienylations has been realized through versatile hydroarylations of allenes with ample scope. Thus, an inexpensive nickel catalyst modified with a N‐heterocyclic carbene ligand enabled the direct transformation of C−H bonds of biologically relevant imidazole and purine derivatives with full control of regio‐ and chemoselectivity.
Design of the phthalonitrile‐based composite laminates by improving the interfacial compatibility and their enhanced properties
Authors: Ren Dengxun , Lei Yangxue , Pan Hai , Yan Liang , Xu Mingzhen , Liu Xiaobo 
Published: October 2017

ABSTRACTPhthalonitrile containing benzoxazine (BA‐ph) and cyanate ester (CE) were chosen as the thermosetting matrix and the glass fiber (GF) reinforced laminates formed at low temperature were designed. The polyarylene ether nitriles containing pendent carboxyl groups (CPEN) was selected to modify the interfacial interaction between the resin matrix and GFs. Two methods of introducing CPEN were compared and the effects of CPEN on curing behaviors and properties of the composites were investigated. Results showed that with the CPEN, exothermic peaks shifted to lower temperature and curing temperatures of BA‐ph/CE decreased slightly. The mechanical and thermal properties of GF‐reinforced composites were discussed and the results indicated that the composites of modified GFs with CPEN exhibited outstanding mechanical properties, higher glass transition temperature (Tg > 290 °C) than that of composites composed of CPEN mixed with BA‐ph/CE. Moreover, GF‐reinforced composites showed stable dielectric constants (3.8–4.5) and low dielectric loss (0.005–0.01), which were independent of the frequency. In sum, the various methods of the introduction of CPEN in the GF‐reinforced composites may provide a new route to prepare improved composites, meanwhile, composites with outstanding processability and excellent mechanical and thermal properties are expected to be widely applied in the fields of high‐performance structural materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45881.
Dual Mechanism of an Intramolecular Charge Transfer (ICT)–FRET‐Based Fluorescent Probe for the Selective Detection of Hydrogen Peroxide
Authors: Liang Xiao , Xu Xiaoyi , Qiao Dan , Yin Zheng , Shang Luqing 
Published: October 2017

AbstractA dual‐mechanism intramolecular charge transfer (ICT)–FRET fluorescent probe for the selective detection of H2O2 in living cells has been designed and synthesized. This probe used a coumarin–naphthalimide hybrid as the FRET platform and a boronate moiety as the recognition group. Upon the addition of H2O2, the probe exhibited a redshifted (73 nm) fluorescence emission, and the ratio of fluorescence intensities at λ=558 and 485 nm (F558/F485) shifted notably (up to 100‐fold). Moreover, there was a good linearity (R2=0.9911) between the ratio and concentration of H2O2 in the range of 0 to 60 μm, with a limit of detection of 0.28 μm (signal to noise ratio (S/N)=3). This probe could also detect enzymatically generated H2O2. Importantly, it could be used to visualize endogenous H2O2 produced by stimulation from epidermal growth factor.
Effects of scaffold microstructure and low intensity pulsed ultrasound on chondrogenic differentiation of human mesenchymal stem cells
Authors: Aliabouzar Mitra , Lee Se‐jun , Zhou Xuan , Zhang Grace Lijjie , Sarkar Kausik 
Published: October 2017

AbstractThe effects of low intensity pulsed ultrasound (LIPUS) on proliferation and chondrogenic differentiation of human mesenchymal stem cells (hMSCs) seeded on 3D printed poly‐(ethylene glycol)‐diacrylate (PEG‐DA) scaffolds with varying pore geometries (square and hexagonal channels) were investigated. The scaffold with square pores resulted in higher hMSC growth and chondrogenic differentiation than a solid or a hexagonally porous scaffold. The optimal LIPUS parameters at 1.5 MHz were found to be 100 mW/cm2 and 20% duty cycle. LIPUS stimulation increased proliferation by up to 60% after 24 hr. For chondrogenesis, we evaluated key cartilage biomarkers abundant in cartilage tissue; glycosaminoglycan (GAG), type II collagen and total collagen. LIPUS stimulation enhanced GAG synthesis up to 16% and 11% for scaffolds with square and hexagonal patterns, respectively, after 2 weeks. Additionally, type II collagen production increased by 60% and 40% for the same patterns, respectively under LIPUS stimulation after 3 weeks. These results suggest that LIPUS stimulation, which has already been approved by FDA for treatment of bone fracture, could be a highly efficient tool for tissue engineering in combination with 3D printing and hMSCs to regenerate damaged cartilage tissues.
The effect of previous causal knowledge on the persuasive strength of confirming covariation data
Authors: Saporta‐Sorozon Kelly , Bar‐Eli Michael 
Published: October 2017

AbstractConsumers are often exposed to causal claims (e.g., a new pill that claims to treat acne) that are occasionally accompanied by data indicating that the product (target) performed better than another product (referent). In this study, we examined the effect of such data on persuasion as a function of target–referent similarity in causal features. Consistent with current theorizing suggesting that structural and specific preexisting causal knowledge affects data interpretation, we propose that data that are consistent with expectations will be more persuasive than data that are inconsistent with expectations. Specifically, we contend that the structural schema “control of variables” we use leads us to expect that two categories (products) that are similar in features will perform the same and two categories that differ in features will differ in performance. In addition, our specific knowledge on causal powers leads us to expect the target to perform better than the referent only if it has more causal features. Thus, when confronted with data indicating a target performed better than a referent with fewer causal features, the reasoner will find it easier to explain the data, and hence, the difference in performance will be perceived as larger, and the message will be more persuasive (e.g., belief in the causal claim and willingness to purchase the product) than when the target has the same causal features as the referent. The results of three studies revealed the expected pattern for different products, promising different effects in different communication contexts.
Supported Electrospun Ultrafine Fibrous Poly(tetrafluoroethylene)/ZnO Porous Membranes and their Photocatalytic Applications
Authors: Huang Yan , Huang Qinglin , Xiao Changfa , You Yanwei , Zhang Chaoxin , Liu Huan 
Published: October 2017

AbstractSupported photocatalytic poly(tetrafluoroethylene) (PTFE)/ZnO porous membranes were prepared by sintering electrospun PTFE/poly(vinylalcohol)/zinc acetate dehydrate composite membranes. Electrospun PTFE membranes were utilized as supports with excellent chemical stability and high specific surface area, while the photocatalyst‐ZnO particles derived from the thermal decomposition of zinc acetate dehydrate were homogeneously immobilized on the surface of ultrafine PTFE fibers. The PTFE/ZnO membranes could be easily recovered and reused after water treatment. PTFE/ZnO membranes are expected to have a wide range of potential applications in photocatalysis and photocatalysis‐membrane reactors, playing the role of a catalyst as well as a selective barrier against contaminants of interest.
Synthesis of Nanocomposite Poly(vinyl alcohol)‐Tin Oxide Mixed‐Matrix Membranes for Textile Effluent Treatment
Authors: Babu Jibin , Murthy Zagabathuni Venkata Panchakshari 
Published: October 2017

AbstractThin‐film nanocomposite membranes were prepared by dip‐coating poly(vinyl alcohol) (PVA) and tin oxide (SnO2) nanoparticles over a polyethersulfone membrane support. PVA was cross‐linked using malic acid for stability. The membranes were characterized by Fourier transform infrared spectroscopy, field emission gun‐scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, thermogravimetric analysis, atomic force microscopy, and contact angle measurement; and nanoparticles, by dynamic light scattering and transmission electron microscopy. The membranes were subjected to filtration of synthetic dyes wastewater. The performance of the prepared membranes was compared with those of membranes without SnO2 nanoparticles. A fouling study was conducted using humic acid. The structural properties of the membranes were calculated using the extended Nernst‐Planck equation.
An Amino‐Functionalized Metal‐Organic Framework, Based on a Rare Ba12(COO)18(NO3)2 Cluster, for Efficient C3/C2/C1 Separation and Preferential Catalytic Performance
Authors: Fan Weidong , Wang Yutong , Zhang Qian , Kirchon Angelo , Xiao Zhenyu , Zhang Liangliang , Dai Fangna , Wang Rongming , Sun Daofeng 
Published: October 2017

AbstractA barium(II) metal‐organic framework (MOF) based on a predesigned amino‐functionalized ligand, namely [Ba2(L)(DMF)(H2O)(NO3)1/3]⋅DMF⋅EtOH⋅2 H2O (UPC‐33) [H3L=4,4′‐((2‐amino‐5‐carboxy‐1,3‐phenylene)bis(ethyne‐2,1‐diyl))dibenzoic acid] has been synthesized. UPC‐33 is a 3‐dimensional 3,18‐connected network with fcu topology with a rare twelve‐nuclear Ba12(COO)18(NO3)2 cluster. UPC‐33 shows permanent porosity and a high adsorption heat of CO2 (49.92 kJ mol−1), which can be used as a platform for selective adsorption of CO2/CH4 (8.09). In addition, UPC‐33 exhibits high separation selectivity for C3 light hydrocarbons with respect to CH4 (228.34, 151.40 for C3H6/CH4, C3H8/CH4 at 273k and 1 bar), as shown by single component gas sorption and selectivity calculations. Due to the existence of −NH2 groups in the channels, UPC‐33 can effectively catalyze Knoevenagel condensation reactions with high yield, and substrate size and electron dependency.
An On‐Surface Reaction Confined within a Porous Molecular Template
Authors: Judd Chris J. , Champness Neil R. , Saywell Alex 
Published: October 2017

AbstractOn‐surface reactions based on metal‐catalysed Ullmann coupling have been successfully employed to synthesise a wide variety of covalently coupled structures. Substrate chemistry and topology are both known to effect the progression of an on‐surface reaction; offering routes to control efficiency and selectivity. Here, we detail ultra‐high vacuum scanning probe microscopy experiments showing that templating a catalytically active surface, via a supramolecular template, influences the reaction pathway of an on‐surface Ullmann‐type coupling reaction by inhibiting one potential intermediate structure and stabilising another.
Inhibitory neuron‐specific Cre‐dependent red fluorescent labeling using VGAT BAC‐based transgenic mouse lines with identified transgene integration sites
Authors: Kaneko Ryosuke , Takatsuru Yusuke , Morita Ayako , Amano Izuki , Haijima Asahi , Imayoshi Itaru , Tamamaki Nobuaki , Koibuchi Noriyuki , Watanabe Masahiko , Yanagawa Yuchio 
Published: October 2017

AbstractInhibitory neurons are crucial for shaping and regulating the dynamics of the entire network, and disturbances in these neurons contribute to brain disorders. Despite the recent progress in genetic labeling techniques, the heterogeneity of inhibitory neurons requires the development of highly characterized tools that allow accurate, convenient, and versatile visualization of inhibitory neurons in the mouse brain. Here, we report a novel genetic technique to visualize the vast majority and/or sparse subsets of inhibitory neurons in the mouse brain without using techniques that require advanced skills. We developed several lines of Cre‐dependent tdTomato reporter mice based on the vesicular GABA transporter (VGAT)‐BAC, named VGAT‐stop‐tdTomato mice. The most useful line (line #54) was selected for further analysis based on two characteristics: the inhibitory neuron‐specificity of tdTomato expression and the transgene integration site, which confers efficient breeding and fewer adverse effects resulting from transgene integration‐related genomic disruption. Robust and inhibitory neuron‐specific expression of tdTomato was observed in a wide range of developmental and cellular contexts. By breeding the VGAT‐stop‐tdTomato mouse (line #54) with a novel Cre driver mouse line, Galntl4‐CreER, sparse labeling of inhibitory neurons was achieved following tamoxifen administration. Furthermore, another interesting line (line #58) was generated through the unexpected integration of the transgene into the X‐chromosome and will be used to map X‐chromosome inactivation of inhibitory neurons. Taken together, our studies provide new, well‐characterized tools with which multiple aspects of inhibitory neurons can be studied in the mouse.