bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regio‐ and Enantioselective (3+3) Cycloaddition of Nitrones with 2‐Indolylmethanols Enabled by Cooperative Organocatalysis
Authors: Li Tian‐Zhen , Liu Si‐Jia , Sun Yu‐Wen , Deng Shuang , Tan Wei , Jiao Yinchun , Zhang Yu‐Chen , Shi Feng 
Published: October 2020

AbstractThe regio‐ and enantioselective (3+3) cycloaddition of nitrones with 2‐indolylmethanols was accomplished by the cooperative catalysis of hexafluoroisopropanol (HFIP) and chiral phosphoric acid (CPA). Using this approach, a series of indole‐fused six‐membered heterocycles were synthesized in high yields (up to 98 %), with excellent enantioselectivities (up to 96 % ee) and exclusive regiospecificity. This approach enabled not only the first organocatalytic asymmetric (3+3) cycloaddition of nitrones but also the first C3‐nucleophilic asymmetric (3+3) cycloaddition of 2‐indolylmethanols. More importantly, theoretical calculations elucidated the role of the cocatalyst HFIP in helping CPA control the reactivity and enantioselectivity of the reaction, demonstrating a new mode of cooperative catalysis.
Acquiring High‐TC Layered Metal Halide Ferroelectrics via Cage‐Confined Ethylamine Rotators
Authors: Peng Yu , Bie Jie , Liu Xitao , Li Lina , Chen Shuang , Fa Wei , Wang Sasa , Sun Zhihua , Luo Junhua 
Published: October 2020

AbstractTwo‐dimensional (2D) organic–inorganic hybrid perovskite (OIHP) ferroelectrics have attracted widespread interest in the field of optoelectronics due to the combination of excellent semiconducting and ferroelectric properties. The Curie temperature (TC), below which ferroelectricity exists, is a crucial parameter for ferroelectrics. However, the lack of research on TC tuning of 2D OIHP ferroelectrics hinders their further progress. Here, through incorporating ethylammonium (EA) as cage‐confined rotators, we obtained two 2D OIHP ferroelectrics, (IBA)2(EA)Pb2Br7 (2L; IBA=isobutylammonium), and (IBA)2(EA)2Pb3Br10 (3L). Intriguingly, TC is successfully tuned from 326 K (2L) to 370 K (3L) with increasing layer thickness. Structural and computational analyses suggest that the improvement of TC is due to the higher phase‐transition energy barrier triggered by the cage‐confined EA rotators with increased layer thickness. This work suggests that EA is an effective “cage‐confined rotator” to rationally design high‐TC 2D OIHP ferroelectrics.
How Oxygen Binding Enhances Long‐Range Electron Transfer: Lessons From Reduction of Lytic Polysaccharide Monooxygenases by Cellobiose Dehydrogenase
Authors: Wang Zhanfeng , Feng Shishi , Rovira Carme , Wang Binju 
Published: October 2020

AbstractLong‐range electron transfer (ET) in metalloenzymes is a general and fundamental process governing O2 activation and reduction. Lytic polysaccharide monooxygenases (LPMOs) are key enzymes for the oxidative cleavage of insoluble polysaccharides, but their reduction mechanism by cellobiose dehydrogenase (CDH), one of the most commonly used enzymatic electron donors, via long‐range ET is still an enigma. Using multiscale simulations, we reveal that interprotein ET between CDH and LPMO is mediated by the heme propionates of CDH and solvent waters. We also show that oxygen binding to the copper center of LPMO is coupled with the long‐range interprotein ET. This process, which is spin‐regulated and enhanced by the presence of O2, directly leads to LPMO−CuII−O2−, bypassing the formation of the generally assumed LPMO−CuI species. The uncovered ET mechanism rationalizes experimental observations and might have far‐reaching implications for LPMO catalysis as well as the O2‐ or CO‐binding‐enhanced long‐range ET processes in other metalloenzymes.
Single‐Step Sulfur Insertions into Iron Carbide Carbonyl Clusters: Unlocking the Synthetic Door to FeMoco Analogues
Authors: Joseph Chris , Cobb Caitlyn R. , Rose Michael J. 
Published: October 2020

AbstractThe one‐step syntheses, X‐ray structures, and spectroscopic characterization of synthetic iron clusters, bearing either inorganic sulfides or thiolate with interstitial carbide motifs, are reported. Treatment of iron carbide carbonyl clusters [Fen(μn‐C)(CO)m]x (n=5,6; m=15,16; x=0,−2) with electrophilic sulfur sources (S2Cl2, S8) results in the formation of several μ4‐S dimers of clusters, and moreover, iron‐sulfide‐(sulfocarbide) clusters. The core sulfocarbide unit {C−S}4− serves as a structural model for a proposed intermediate in the radical S‐adenosyl‐L‐methionine biogenesis of the M‐cluster. Furthermore, the electrophilic sulfur strategy has been extended to provide the first ever thiolato‐iron‐carbide complex: an analogous reaction with toluylsulfenyl chloride affords the cluster [Fe5(μ5‐C)(SC7H7)(CO)13]−. The strategy described herein provides a breakthrough towards developing syntheses of biomimetic iron‐sulfur‐carbide clusters like FeMoco.
Direct Self‐Assembly of MXene on Zn Anodes for Dendrite‐Free Aqueous Zinc‐Ion Batteries
Authors: Zhang Nannan , Huang Shuo , Yuan Zishun , Zhu Jiacai , Zhao Zifang , Niu Zhiqiang 
Published: October 2020

AbstractMetallic zinc is a promising anode candidate of aqueous zinc‐ion batteries owing to its high theoretical capacity and low redox potential. However, Zn anodes usually suffer from dendrite and side reactions, which will degrade their cycle stability and reversibility. Herein, we developed an in situ spontaneously reducing/assembling strategy to assemble a ultrathin and uniform MXene layer on the surface of Zn anodes. The MXene layer endows the Zn anode with a lower Zn nucleation energy barrier and a more uniformly distributed electric field through the favorable charge redistribution effect in comparison with pure Zn. Therefore, MXene‐integrated Zn anode exhibits obviously low voltage hysteresis and excellent cycling stability with dendrite‐free behaviors, ensuring the high capacity retention and low polarization potential in zinc‐ion batteries.
Biomimetic Recognition and Optical Sensing of Carboxylic Acids in Water by Using a Buried Salt Bridge and the Hydrophobic Effect
Authors: Huang Xuan , Wang Xiaoping , Quan Mao , Yao Huan , Ke Hua , Jiang Wei 
Published: October 2020

AbstractBuried salt bridges widely exist in protein structures but are rarely used in synthetic systems for molecular recognition in water. By mimicking the binding pocket of bioreceptors, we designed and synthesized a pair of endo‐functionalized macrocyclic hosts with secondary ammonium groups in a hydrophobic cavity. We found that these macrocycles are able to selectively recognize carboxylic acids in water through salt bridges and the hydrophobic effect. Moreover, it was demonstrated that these macrocyclic receptors can be used in circular‐dichroism‐based optical chirality sensing of chiral carboxylic acids and fluorescent sensing of phenylpyruvic acid—a biomarker for phenylketonuria. This research showcases that buried salt bridges can be effectively used by endo‐functionalized macrocyclic hosts for molecular recognition in water, where solvent screening on polar noncovalent interactions is high.
Going Platinum to the Tune of a Remarkable Guanine Quadruplex Binder: Solution‐ and Solid‐State Investigations.
Authors: Miron Caitlin E. , van Staalduinen Laura , Rangaswamy Alana M. , Chen Mickey , Liang Yushi , Jia Zongchao , Mergny Jean‐Louis , Petitjean Anne 
Published: October 2020

AbstractGuanine quadruplex recognition has gained increasing attention, inspired by the growing awareness of the key roles played by these non‐canonical nucleic acid architectures in cellular regulatory processes. We report here the solution and solid‐state studies of a novel planar platinum(II) complex that is easily assembled from a simple ligand, and exhibits notable binding affinity for guanine quadruplex structures, while maintaining good selectivity for guanine quadruplex over duplex structures. A crystal structure of this ligand complexed with a telomeric quadruplex confirms double end‐capping, with dimerization at the 5′ interface.
Multi‐Mode Color‐Tunable Long Persistent Luminescence in Single‐Component Coordination Polymers
Authors: Wang Zheng , Zhu Cheng‐Yi , Mo Jun‐Ting , Xu Xian‐Yan , Ruan Jia , Pan Mei , Su Cheng‐Yong 
Published: October 2020

AbstractMaterials with tunable long persistent luminescence (LPL) properties have wide applications in security signs, anti‐counterfeiting, data encrypting, and other fields. However, the majority of reported tunable LPL materials are pure organic molecules or polymers. Herein, a series of metal‐organic coordination polymers displaying color‐tunable LPL were synthesized by the self‐assembly of HTzPTpy ligand with different cadmium halides (X=Cl, Br, and I). In the solid state, their LPL emission colors can be tuned by the time‐evolution, as well as excitation and temperature variation, realizing multi‐mode dynamic color tuning from green to yellow or green to red, and are the first such examples in single‐component coordination polymer materials. Single‐crystal X‐ray diffraction analysis and theoretical calculations reveal that the modification of LPL is due to the balanced action from single molecule and aggregate triplet excited states caused by an external heavy‐atom effect. The results show that the rational introduction of different halide anions into coordination polymers can realize multi‐color LPL.
The Origin of Selective Adsorption of CO2 on Merlinoite Zeolites
Authors: Choi Hyun June , Jo Donghui , Min Jung Gi , Hong Suk Bong 
Published: October 2020

AbstractThe CO2 adsorption behavior at 25–75 °C and 0–1.0 bar of various alkali cation‐exchanged forms of merlinoite (framework type MER) zeolites with Si/Al=2.3 and 3.8 is described. The adsorption isotherms at 25 °C on the Na+, K+, Rb+, and Cs+ forms of MER zeolite with Si/Al=2.3 are characterized by a clear step, the CO2 pressure of which differs notably according to the type of their extraframework cations. Structural analysis shows that CO2 adsorption on the former three zeolites includes the relocation of gating cations with high site occupancy and the remarkable concomitant structural breathing. We define this unusual adsorption phenomenon as a cooperative cation gating‐breathing mechanism. The overall results suggest that the actual mechanism of selective CO2 adsorption on intermediate‐silica small‐pore zeolites can change from cation gating to cooperative cation gating‐breathing to breathing, depending on a combination of their topological and compositional flexibilities.
Sub‐3 nm Ultrafine Cu2O for Visible Light Driven Nitrogen Fixation
Authors: Zhang Shuai , Zhao Yunxuan , Shi Run , Zhou Chao , Waterhouse Geoffrey I. N. , Wang Zhuan , Weng Yuxiang , Zhang Tierui 
Published: October 2020

AbstractCu2O, a low‐cost, visible light responsive semiconductor photocatalyst represents an ideal candidate for visible light driven photocatalytic reduction of N2to NH3from the viewpoint of thermodynamics, but it remains unexplored. Reported here is the successful synthesis of uniformly sized and ultrafine Cu2O platelets, with a lateral size of <3 nm, by the in situ topotactic reduction of a CuII‐containing layered double hydroxide with ascorbic acid. The supported ultrafine Cu2O offered excellent performance and stability for the visible light driven photocatalytic reduction of N2to NH3(the Cu2O‐mass‐normalized rate as high as 4.10 mmol g−1 h−1atλ>400 nm), with the origin of the high activity being long‐lived photoexcited electrons in trap states, an abundance of exposed active sites, and the underlying support structure. This work guides the future design of ultrafine catalysts for NH3synthesis and other applications.
A Tubular DNA Nanodevice as a siRNA/Chemo‐Drug Co‐delivery Vehicle for Combined Cancer Therapy
Authors: Wang Zhaoran , Song Linlin , Liu Qing , Tian Run , Shang Yingxu , Liu Fengsong , Liu Shaoli , Zhao Shuai , Han Zihong , Sun Jiashu , Jiang Qiao , Ding Baoquan 
Published: October 2020

AbstractUsing the DNA origami technique, we constructed a DNA nanodevice functionalized with small interfering RNA (siRNA) within its inner cavity and the chemotherapeutic drug doxorubicin (DOX), intercalated in the DNA duplexes. The incorporation of disulfide bonds allows the triggered mechanical opening and release of siRNA in response to intracellular glutathione (GSH) in tumors to knockdown genes key to cancer progression. Combining RNA interference and chemotherapy, the nanodevice induced potent cytotoxicity and tumor growth inhibition, without observable systematic toxicity. Given its autonomous behavior, exceptional designability, potent antitumor activity and marked biocompatibility, this DNA nanodevice represents a promising strategy for precise drug design for cancer therapy.
Wear and thermal behavior of basalt fiber reinforced rice husk/polyvinyl chloride composites
Authors: Jiang Liangpeng , Fu Jingjing , Liu Lihong , Du Peng 
Published: October 2020

AbstractPlant fiber reinforced polymer composites (PFRPs) in practical application are often subjected to both complex friction and variable temperature environments. The present work explores the possibility of reinforcing rice husk/polyvinyl chloride (RH/PVC) composites with basalt fibers (BF) for developing a new wear resistant material with improved thermal stability. The results showed that the structural strength and wear resistance of the composites increased at first and then decreased with an increasing ratio of BF/RH, the highest value occurred at a BF/RH ratio of 8/42. The thermal stability of composites had a positive relationship with BF/RH ratio. The composites added with BF all possessed improved performance in comparison with unadded composites. Hence, the findings of this article proposed some new perspectives on improving the wear resistance and thermal stability of PFRPs that would broaden their practical application.
Advances in Lentivirus Purification
Authors: Moreira Ana Sofia , Cavaco David Guia , Faria Tiago Q. , Alves Paula M. , Carrondo Manuel J. T. , Peixoto Cristina 
Published: October 2020

AbstractLentiviral vectors (LVs) have been increasingly used as a tool for gene and cell therapies since they can stably integrate the genome in dividing and nondividing cells. LV production and purification processes have evolved substantially over the last decades. However, the increasing demands for higher quantities with more restrictive purity requirements are stimulating the development of novel materials and strategies to supply the market with LV in a cost‐effective manner. A detailed review of each downstream process unit operation is performed, limitations, strengths, and potential outcomes being covered. Currently, the majority of large‐scale LV manufacturing processes are still based on adherent cell culture, although it is known that the industry is migrating fast to suspension cultures. Regarding the purification strategy, it consists of batch chromatography and membrane technology. Nevertheless, new solutions are being created to improve the current production schemes and expand its clinical use.
Purchasing luck: The impact of scarcity cues on superstitious behavior
Authors: Wang Lili , Su Xiao , You Yanfen 
Published: October 2020

AbstractResource scarcity is prevalent in consumers' everyday lives. In contrast to the prior research suggesting that resource scarcity rationalizes consumers' decision‐making, this research examines when and why resource scarcity enhances consumers' superstitiousness, as represented by their preferences for lucky products. Six studies demonstrate that resource scarcity arouses consumers' desire for control, which, in turn, drives consumers to pursue lucky products. The paper concludes with a discussion of the theoretical and empirical implications of the results.
Expanding the stroke team to include interventional cardiology
Authors: Mendelsohn Farrell O. , Holmes David R. , Hopkins L. Nelson 
Published: October 2020

AbstractTeam‐based care has been emphasized as a strategy to improve and optimize outcomes for broad groups of patients who have presented with often complex medical conditions including large vessel cerebral occlusion. Although neurointerventionalists from different specialties perform mechanical embolectomy, which has become the standard of care for large vessel cerebral occlusion, these specialties are limited by relatively low numbers typically concentrated in a small number of sites. In this single center experience, approximately 50 patients with large vessel stroke were transferred out of an emergency room to other centers despite the availability of an experienced cardiologist with extensive carotid experience. Such transfer strategies typically result in delays in receiving reperfusion and, therefore, may decrease the success rates and substantial improvement that can be obtained by patients in this setting. Trained interventional cardiologists in centers with limited 24/7/365 coverage could achieve rapid revascularization and reperfusion saving lives. In order to accommodate the need for treating these patients, carotid stent trained cardiologists should enter the arena, learn mechanical embolectomy, and be supported by their colleagues from other disciplines on acute stroke care teams.
A Straightforward Synthesis of Polyketides via Ester Dienolate Matteson Homologation
Authors: Andler Oliver , Kazmaier Uli 
Published: October 2020

AbstractApplication of ester dienolates as nucleophiles in Matteson homologations allows for the stereoselective synthesis of highly substituted α,β‐unsaturated δ‐hydroxy carboxyl acids, structural motifs widespread found in polyketide natural products. The protocol is rather flexible and permits the introduction of substituents and functionalities also at those positions which are not accessible by the commonly used aldol reaction. Therefore, this ester dienolate Matteson approach is an interesting alternative to the “classical” polyketide syntheses.
Aggregation‐Induced Emission: A Rising Star in Chemistry and Materials Science
Authors: Han Ting , Yan Dingyuan , Wu Qian , Song Nan , Zhang Haoke , Wang Dong 
Published: October 2020

AbstractAggregation‐induced emission (AIE) refers to a photophysical effect that the luminescence of aggregates is stronger than that of the dispersed state. Since the concept of AIE was coined by Professor Ben Zhong Tang and co‐workers in 2001, AIE has evolved from a simple luminescent phenomenon to a multidisciplinary research field with a widespread influence. It has changed people's way of thinking about chromophore aggregation and greatly promoted the development of advanced luminescent materials. During the 20‐year development, diverse AIE luminogens (AIEgens) with attractive functionalities have been developed and remarkable achievements have been made in the mechanistic study and high‐tech applications of AIEgens. In this review, we provide an overview of the historical development and representative achievements of AIE research. Perspectives on the application of AIE in aggregate science are also briefly discussed to guide the future development in this field.
A Composite Membrane Based on Sulfonated Polystyrene Implanted in a Stretched PTFE Film for Vanadium Flow Batteries
Authors: Gvozdik Nataliya A. , Sanginov Evgeny A. , Abunaeva Lilia Z. , Konev Dmirty V. , Usenko Andrey A. , Novikova Ksenia S. , Stevenson Keith J. , Dobrovolsky Yury A. 
Published: October 2020

AbstractThe quality of ion‐selective membranes determines the efficiency of Vanadium Flow Batteries (VFBs), and alternatives to expensive Nafion™ materials are actively being searched for. One of the membrane architecture approaches is to imitate the Nafion™ structure with two separate phases: a conductive sulfonated polymer and an inner matrix. We introduce a new composite material based on sulfonated styrene polymerized inside the pores of a stretched PTFE matrix. Variation of polystyrene content and a sulfonation degree allowed to obtain membranes with IEC from to 0.96 to 1.84 mmol/g. Balanced vanadium permeability (ca. 5.5 ⋅ 10−6 cm2/min) and proton conductivity (ca. 50 mS/cm) were achieved for the material with 21–23 % polystyrene content and a sulfonation degree up to 94 %. Membranes showed stable cycling with 81 % energy efficiency in a single‐cell VFB. This work contributes to the existing knowledge of Nafion alternatives by providing a cheap and scalable method of membrane production.
Validity of a Norwegian version of the Desire Thinking Questionnaire (DTQ): Associations with problem drinking, nicotine dependence and problematic social media use
Authors: Solem Stian , Pedersen Henrik , Nesse Frikk , Garvik Janssen Arne , Ottesen Kennair Leif Edward , Hagen Roger , Havnen Audun , Hjemdal Odin , Caselli Gabriele , Spada Marcantonio M. 
Published: October 2020

AbstractThe aim of the current study was to test the validity of the Norwegian version of the Desire Thinking Questionnaire (DTQ). Three cross‐sectional surveys were conducted investigating the psychometric properties of the DTQ in alcohol use (N = 588), nicotine use (N = 446) and social media use (N = 359). Principal components and confirmatory factor analyses supported the original two‐factor solution consisting of verbal perseveration (VP) and imaginal prefiguration (IP); however, one item was removed to obtain good fit. Internal consistency was acceptable. Both IP and VP showed significant correlations with problem drinking, nicotine dependence and problematic social media use. Regression analyses, controlling for demographics and negative affect, found IP and VP to be significantly associated with all dependent variables. The results confirm that desire thinking is an important construct across different addictive behaviours.
Transition‐Metal‐Free Valorization of Biomass‐derived Levulinic Acid Derivatives: Synthesis of Curcumene and Xanthorrhizol
Authors: Xu Wen‐Yan , Zhuo Kai‐Feng , Gong Tian‐Jun , Fu Yao 
Published: October 2020

AbstractLevulinic acid (LA) is acknowledged one of the most promising biomass‐derived platform molecules and can be transformed into various value‐added chemicals. Here, we report a new reaction process for the valorization of LA derivatives under transition‐metal‐free condition. The protocol combined with the conversion of the levulinate to tosylhydrazone and base promoted arylation, acylation, and etherification cross‐coupling. Moreover, our method was applied to synthesize three biologically active molecules, rac‐curcumene, rac‐xanthorrhizol and rac‐4,7‐dimethyl‐l‐tetralone. This reaction discloses a new avenue for the high‐value utilization of platform molecules.