bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydroaminocarbonylation of Alkynes to Produce Primary α,β‐Unsaturated Amides Using NH4HCO3 Dually as Ammonia Surrogate and Brønsted Acid Additive
Authors: Wang Dong‐Liang , Guo Wen‐Di , Zhou Qing , Liu Lei , Lu Yong , Liu Ye 
Published: July 2018

AbstractBy using NH4HCO3 dually as ammonia surrogate and Brønsted acid additive, the production of primary α,β‐unsaturated amides via hydroaminocarbonylation of alkynes was accomplished efficiently. The advantages of using the solid and inexpensive NH4HCO3 included: (1) the facile and clean manipulation without presence of stinky gaseous NH3 or liquids organic amines, (2) the inhibition of the subsequent dehydration and hydrolysis of amides due to its weak basicity, and (3) the facilitated formation of Pd−H catalytic active species by the released H2CO3 serving as a weak Brønsted acid additive. In addition, the diphopshine of Dppp with the natural bite angle (βn) of 91° was found indispensable to spur the performance of the palladium catalyst for this reaction. Both terminal and internal phenylacetylene derivatives could be used as the substrates, affording the corresponding primary α,β‐unsaturated amides in good yields along with excellent regio‐selectivities to the branched ones.
Probing Nitrogen‐Doping Effects in the Core‐Shell Structured Catalysts for Bifunctional Electrocatalysis.
Authors: Li Qianru , Wan Gang , Zhao Wanpeng , Yang Ce , Peng Chunlei , Duan Zhengli , Chen Hangrong 
Published: July 2018

AbstractThe design of core‐shell structured catalysts has attracted wide interests due to their remarkable catalytic performances in many fields. Although the nitrogen doping is often integrated in such kind of catalysts, the main contribution is exclusively attributed to the metal sites or the core‐shell configuration. The role of nitrogen doping is often believed to be less important, which remains largely unexplored. Here, in an effort to probe the catalytic role of heterogeneous doping in such core‐shell structure, the effect of nitrogen doping on the activation of cobalt and iron carbide‐based materials for the electrocatalytic reduction of oxygen and the hydrogen evolution reaction is originally revealed. The nitrogen doping in the core‐shell structured biphasic interfaces is found to be of critical importance for triggering the electrocatalytic activity and selectivity. Therefore, this study shows the neglected but critical role of nitrogen doping and biphasic interactions in a core‐shell configuration, paving a new pathway towards the performance enhancement.
Temperature Effects on Concentration Polarization Thickness in Thin‐Film Composite Reverse Osmosis Membranes
Authors: Baghdadi Yasmine N. , Alnouri Sabla Y. , Matsuura Takeshi , Tarboush Belal J. Abu 
Published: July 2018

AbstractContinuous research and development of reverse osmosis (RO) technologies has led to the production of membranes that are very effective with high salt rejection abilities. As temperature is one of the factors that affects salt rejection capabilities in membranes, this paper investigates the effect of temperature on the thickness of the concentration polarization layer (CPL) deposited on thin‐film composite seawater RO membranes. Two types of membranes were studied: those with ex situ macromolecules and those with in situ macromolecules. FilmTec's reverse osmosis system analysis design software was used to predict the variation of salt rejection and permeate flow rate with temperature. The impact of these variations on the thickness of the CPL was analyzed for different polyamide concentrations in the membrane.
Spatially Resolved Characterization of the Gas Propagator in Monolithic Structured Catalysts Using NMR Diffusiometry
Authors: Mirdrikvand Mojtaba , Ilsemann Jan , Thöming Jorg , Dreher Wolfgang 
Published: July 2018

AbstractGas diffusivity measurements in opaque porous media were performed using nuclear magnetic resonance. An optimized pulsed‐field gradient stimulated echo method with free volume selection was used to investigate the propagator of thermally polarized methane gas within commercial monolithic catalyst supports. Since signal losses due to T2 relaxation were minimized by using a short echo time, diffusion processes could be characterized by the measured propagator functions and effective diffusion coefficients were determined for a broad range of observation times and in different spatial directions. The study of this noninvasive characterization of gas diffusion found a clear effect of the monolith type and its pore size and coating on the effective gas diffusion coefficient and the apparent tortuosity for a given observation time.
Synthesis and Characterization of Self‐Assembled Chiral FeII2L3 Cages
Authors: Sun Bin , Nurttila Sandra S. , Reek Joost N. H. 
Published: July 2018

AbstractWe present here the synthesis of chiral BINOL‐derived (BINOL=1,1′‐bi‐2‐naphthol) bisamine and bispyridine‐aldehyde building blocks that can be used for the self‐assembly of novel chiral FeII2L3 cages when mixed with an iron(II) precursor. The properties of a series of chiral cages were studied by NMR and circular dichroism (CD) spectroscopy, cold‐spray ionization MS, and molecular modeling. Upon formation of the M2L3 cages, the iron corners can adopt various isomeric forms: mer, fac‐Δ, or fac‐Λ. We found that the coordination geometry around the metal centers in R‐Cages 1 and 2 were influenced by the chiral BINOL backbone only to a limited extent, as a mixture of cages was formed with fac and mer configurations at the iron corners. However, single cage species (fac‐RR‐Cage and fac‐RS‐Cage) that are enantiopure and highly symmetric were obtained by generating these chiral M2L3 cages by using the bispyridine‐aldehyde building blocks in combination with chiral amine moieties to form pyridylimine ligands for coordination to iron. Next to consistent NMR spectra, the CD spectra confirm the configurations fac‐(Λ,Λ) and fac‐(Δ,Δ) corresponding to RR‐ and RS‐Cage, respectively.
Synthesis of Lipid‐Carbohydrate‐Peptidyl‐RNA Conjugates to Explore the Limits Imposed by the Substrate Specificity of Cell Wall Enzymes on the Acquisition of Drug Resistance
Authors: Fonvielle Matthieu , Bouhss Ahmed , Hoareau Coralie , Patin Delphine , Mengin‐Lecreulx Dominique , Iannazzo Laura , Sakkas Nicolas , El Sagheer Affaf , Brown Tom , Ethève‐Quelquejeu Mélanie , Arthur Michel 
Published: July 2018

AbstractConjugation of RNA with multiple partners to obtain mimics of complex biomolecules is limited by the identification of orthogonal reactions. Here, lipid‐carbohydrate‐peptidyl‐RNA conjugates were obtained by post‐functionalization reactions, solid‐phase synthesis, and enzymatic steps, to generate molecules mimicking the substrates of FmhB, an essential peptidoglycan synthesis enzyme of Staphylococcus aureus. Mimics of Gly‐tRNAGly and lipid intermediate II (undecaprenyl‐diphospho‐disaccharide‐pentapeptide) were combined in a single “bi‐substrate” inhibitor (IC50=56 nm). The synthetic route was exploited to generate substrates and inhibitors containing d‐lactate residue (d‐Lac) instead of d‐Ala at the C‐terminus of the pentapeptide stem, a modification responsible for vancomycin resistance in the enterococci. The substitution impaired recognition of peptidoglycan precursors by FmhB. The associated fitness cost may account for limited dissemination of vancomycin resistance genes in S. aureus.
Mechanochromic Switching between Delayed Fluorescence and Phosphorescence of Luminescent Coordination Polymers Composed of Dinuclear Copper(I) Iodide Rhombic Cores
Authors: Kobayashi Atsushi , Yoshida Yuya , Yoshida Masaki , Kato Masako 
Published: July 2018

AbstractThe synthesis and photophysical properties of two luminescent CuI coordination polymers, [Cu2I2(PPh3)2(3‐tpyb)]n and [Cu2I2(PPh3)2(4‐tpyb)]n (Cu‐3‐tpyb and Cu‐4‐tpyb; PPh3=triphenylphosphine, m‐tpyb=1,3,5‐tris(m‐pyridyl)benzene (m=3, 4)), are described. X‐ray structural analysis indicated that one‐dimensional coordination chains comprising rhombic {Cu2I2(PPh3)2} cores and m‐tpyb bridging ligands were formed. Both Cu‐3‐tpyb and Cu‐4‐tpyb exhibited blue‐to‐yellow thermally activated delayed fluorescence (TADF) that originated from mixing of the metal‐to‐ligand and halide‐to‐ligand charge‐transfer excited states and moderate emission quantum yields of 0.29 and 0.27, respectively, at 298 K. Further, mechanochromic luminescence was observed for both complexes. The emission lifetimes indicated that the origin of emission switched from TADF to phosphorescence, which was derived from the triplet cluster‐centered (3CC) emissive state generated by grinding‐induced amorphization.
Fluorooxoborates: Ushering in a New Era of Deep Ultraviolet Nonlinear Optical Materials
Authors: Han Guopeng , Wang Ying , Zhang Bingbing , Pan Shilie 
Published: July 2018

AbstractBorates are one of the most important classes of functional materials, and several hundreds of artificial borates have been synthesized. The substitution of oxygen by fluorine leads to manifold classes of borates. Fluorooxoborates (also known as fluoroborates), in which the F atoms covalently connect with the B atoms, show additional compositional and structural diversity compared to classic borates. Recently, owing to the large polarizability anisotropy, large HOMO–LUMO gaps, and high hyperpolarizability of the oxyfluoride BOxF4−x building blocks, fluorooxoborates have received unprecedented attention in the search for new ultraviolet (UV) and deep‐UV (DUV) nonlinear optical (NLO) materials. Specifically, some compounds have excellent NLO properties that are comparable or superior to KBe2BO3F2, which is the only usable crystal that generates coherent light below 200 nm through a direct second harmonic generation (SHG) process. This Minireview illustrates recent progress on the synthesis, crystal structures, structure‐properties relationships and applications of fluorooxoborates. This paper concludes by highlighting the outstanding opportunities offered by NLO fluorooxoborate crystals as an innovative avenue for DUV all solid‐state coherent light generation.
Isolated Collagen Mimetic Peptide Assemblies Have Stable Triple‐Helix Structures
Authors: Lalande Mathieu , Comby‐Zerbino Clothilde , Bouakil Mathilde , Dugourd Philippe , Chirot Fabien , Poully Jean‐Christophe 
Published: July 2018

AbstractThe origin of the triple‐helix structure and high stability of collagen has been debated for many years. As models of the triple helix and building blocks for new biomaterials, collagen mimetic peptide (CMP) assemblies have been deeply studied in the condensed phase. In particular, it was found that hydroxylation of proline, an abundant post‐translational modification in collagen, increases its stability. Two main hypotheses emerged to account for this behavior: 1) intra‐helix stereoelectronic effects, and 2) the role of water molecules H‐bound to hydroxyproline side‐chains. However, in condensed‐phase investigations, the influence of water cannot be fully removed. Therefore, we employed a combination of tandem ion mobility and mass spectrometries to assess the structure and stability of CMP assemblies in the gas phase. These results show a conservation of the structure and stability properties of triple helix models in the absence of solvent, supporting an important role of stereoelectronic effects. Moreover, evidence that small triple helix assemblies with controlled stoichiometry can be studied in the gas phase is given, which opens new perspectives in the understanding of the first steps of collagen fiber growth.
Extremely Long Lived Localized Singlet Diradicals in a Macrocyclic Structure: A Case Study on the Stretch Effect
Authors: Harada Yuta , Wang Zhe , Kumashiro Shunsuke , Hatano Sayaka , Abe Manabu 
Published: July 2018

AbstractLocalized singlet diradicals have attracted much attention, not only in the field of bond‐homolysis chemistry, but also in nonlinear optical materials. In this study, an extremely long lived localized singlet diradical was obtained by using a new molecular design strategy in which it is kinetically stabilized by means of a macrocycle that increases the molecular strain of the corresponding σ‐bonded compound. Notably, the lifetime of this diradical (14 μs) is two orders of magnitude longer than that of a standard singlet diradical without a macrocyclic structure (≈0.2 μs) at 293 K. The species is persistent below a temperature of 100 K. In addition to the kinetic stabilization of the singlet diradical, the spontaneous oxidation of its corresponding ring‐closed compound at 298 K produced oxygenated products under atmospheric conditions. Apparently, the “stretch effect” induced by the macrocyclic structure plays a crucial role in extending the lifetime of localized singlet diradicals and increasing the reactivity of their corresponding σ‐bonded compounds.
Alkyl Radical Generation by an Intramolecular Homolytic Substitution Reaction between Iron(II) and Trialkylsulfonium Groups
Authors: Jungen Stefan , Chen Peter 
Published: July 2018

AbstractInvited for the cover of this issue are Peter Chen and Stefan Jungen at the Eidgenössische Technische Hochschule (ETH) in Zürich. The image depicts a table‐top firework with the tip of an ion guide used in mass spectrometers that spits out the products of a homolitic substitution reaction between iron(II) and trialkylsulfonium species. Read the full text of the article at 10.1002/chem.201801952.
A Visible‐Light‐Induced Strategy To Construct Osmanaphthalynes, Osmaanthracyne, and Osmaphenanthryne
Authors: Zhang Ming‐Xing , Xu Zhiqiang , Lu Tao , Yin Jun , Liu Sheng Hua 
Published: July 2018

AbstractHerein, we describe a novel, green, and efficient synthesis of a series of different substituted osmanaphthalynes (including ‐H, ‐Br, ‐I, ‐CH3 and ‐CF3) and the first examples of the preparation of α‐osmaanthracyne and α‐osmaphenanthryne by means of a visible light‐induced intramolecular cyclization reaction of their corresponding osmium hydrido alkenylcarbyne complexes. This visible‐light‐driven method provides an efficient and straightforward approach to afford the desired fused metal heterocyclic complexes constructed with an Os atom as the metal center in high yield under mild conditions.
Decarboxylative Organocatalytic Allylic Amination of Morita–Baylis–Hillman Carbamates
Authors: Dočekal Vojtěch , Šimek Michal , Dračínský Martin , Veselý Jan 
Published: July 2018

AbstractThe present study reports the organocatalytic enantioselective allylic amination of Morita–Baylis–Hillman carbamates efficiently catalyzed by a chiral amine in the presence of a Brønsted acid. Chiral allylic amines were produced in high yields (up to 98 %) and enantioselectivities (up to 97 % ee). This method provides an efficient and easily performed route to prepare α‐methylene‐β‐lactams, and other optically active β‐lactams, such as the cholesterol‐lowering drug Ezetimibe.
Self‐Assembled Supramolecular Nanoparticles for Targeted Delivery and Combination Chemotherapy
Authors: Li Bingjie , Feng Zhenzhen , He Leiliang , Li Wenshan , Wang Qing , Liu Jianbo , Huang Jin , Zheng Yan , Ma Yanyun , Yang Xiaohai , Wang Kemin 
Published: July 2018

AbstractIt is challenging but imperative to merge imaging agents and small molecule therapeutics into one nanoentity for diagnosis and treatment. Herein, we constructed polymeric nanoparticles for targeted delivery and combination chemotherapy, which formed through host–guest interactions among three elements: 1) β‐cyclodextrin polymer (poly‐β‐CD), as the backbone of nanoparticles; 2) two antitumor drugs—doxorubicin (DOX) and docetaxel (DTX); and 3) aptamers labeled with adamantane and fluorescein (Ad‐aptamer‐FAM), as recognition elements. First, polymeric nanoparticles, termed self‐assembled supramolecular nanoparticles (SSNPs), were formulated by combining hydrophobic DTX and DOX with poly‐β‐CD via host–guest interactions. Then, the surface of SSNPs modified the aptamer to acquire targeting ability; such nanoparticles were termed targeted self‐assembled supramolecular nanoparticles (T‐SSNPs). As evidenced by MTS assay data, T‐SSNPs exhibited significant selective cytotoxicity toward target cells. The results also indicated that combination drugs achieved a good synergistic effect with a combination index of 0.43. Thus, an effective and simple drug delivery system was constructed for targeted delivery and combination chemotherapy.
Emotionally aligned: Preliminary results on the effects of a mindfulness‐based intervention for depression on congruence between implicit and explicit mood
Authors: Remmers Carina , Zimmermann Johannes , Buxton Alice , Unger Hans‐Peter , Koole Sander L. , Knaevelsrud Christine , Michalak Johannes 
Published: July 2018

BackgroundMindfulness‐based interventions (MBIs) are effective in treating major depression. Because mindfulness involves monitoring and accepting current experiences, it may lead people resolve incongruencies between emotional responses that would otherwise remain unnoticed. Mindfulness may thus foster congruence between implicit and explicit emotions. The current randomized controlled trial tested this notion.MethodsN = 39 patients with an acute depressive episode were randomly assigned to an 8‐week MBI (n = 24) or a psychopharmacological consultation condition (n = 15). Explicit and implicit mood and depressive symptoms were assessed before treatment and at the end of treatment.ResultsCompared with the control condition, patients receiving MBI demonstrated higher congruence between implicit and explicit negative mood after treatment. There was no such difference in congruence of implicit and explicit positive mood. Additional analyses showed that only within the MBI group, individual differences in explicit mood became less stable. In contrast, individual differences in implicit mood remained stable in both groups.LimitationsThere was no control group including an active psychological intervention, the sample was small, and emotional congruence was not assessed within persons.ConclusionsThese findings correspond with the idea that mindfulness reduces incongruencies between implicit and explicit emotional responses. We found preliminary evidence for this effect for negative emotional responses. There was suggestive evidence that congruence arose from the alignment of explicit responses (which became less stable) to implicit responses (which remained stable). Studying the interplay between implicit and explicit processes may shed light on the working mechanisms of clinical‐psychological interventions.
Sequential Preparation of Dual‐Layer Fluorine‐Doped Tin Oxide Films for Highly Efficient Perovskite Solar Cells
Authors: Lee Kun‐Mu , Hou Min‐Yao , Suryanarayanan Vembu , Wu Ming‐Chung 
Published: July 2018

AbstractA dual‐layer fluorine‐doped tin oxide (FTO) film has been fabricated by means of sequential spray pyrolysis for high‐efficiency perovskite solar cells (PSCs). The H‐FTO/L‐FTO dual layer film consists of a H‐FTO layer prepared at high deposition temperature (≈450 °C) and a L‐FTO layer, fabricated at low deposition temperature (≈150 °C), which is used to replace the traditional compact TiO2/FTO layer. The effects of F/Sn molar ratio, precursor solution concentration, and deposition temperature on the electrical, optical, surface morphological, and grain structural characteristics of H‐FTO layers have been studied systematically. With an increase in precursor solution concentration, the mobility and carrier concentration of H‐FTO increases; however, the grain size and sheet resistance decreases as the precursor solution concentration increases. A high deposition temperature results in a large grain size and enhanced haze value. The L‐FTO layer expresses compact layer growth, inconsistent with the H‐FTO surface structure, and possesses excellent electron collection and transport efficiency. The effect of the hole‐blocking characteristics of L‐FTO on the PSC performance is studied. This study provides a novel dual‐layer FTO film to replace the traditional compact TiO2/FTO layer, which is usually prepared by coating TiO2 precursor on FTO following calcination at 450 °C. The H‐FTO/L‐FTO dual‐layer film can simplify the fabrication process and maintain a high power conversion efficiency (PCE); this results in more efficient electron transportation and blocking of holes. The champion device of PSCs with H‐FTO/L‐FTO shows the highest PCE of 17.37 % under the illumination of 100 mW cm−2 (AM1.5G).
The Phosphodiesterase 9 Inhibitor PF‐04449613 Promotes Dendritic Spine Formation and Performance Improvement after Motor Learning
Authors: Lai Baoling , Li Miao , Hu Wanling , Li Wei , Gan Wen‐Biao 
Published: July 2018

ABSTRACTThe cyclic nucleotide cGMP is an intracellular second messenger with important roles in neuronal functions and animals' behaviors. The phosphodiesterases (PDEs) are a family of enzymes that hydrolyze the second messengers cGMP and cAMP. Inhibition of phosphodiesterase 9 (PDE9), a main isoform of PDEs hydrolyzing cGMP, has been shown to improve learning and memory as well as cognitive function in rodents. However, the role of PDE9 in regulating neuronal structure and function in vivo remains unclear. Here we used in vivo two‐photon microscopy to investigate the effect of a selective PDE9 inhibitor PF‐04449613 on the activity and plasticity of dendritic spines of layer V pyramidal neurons in the mouse primary motor cortex. We found that administration of PF‐04449613 increased calcium activity of dendrites and dendritic spines of layer V pyramidal neurons in mice under resting and running conditions. Chronic treatment of PF‐04449613 over weeks increased dendritic spine formation and elimination under basal conditions. Furthermore, PF‐04449613 treatment over 1–7 days increased the formation and survival of new spines as well as performance improvement after rotarod motor training. Taken together, our studies suggest that elevating the level of cGMP with the PDE9 inhibitor PF‐04449613 increases synaptic calcium activity and learning‐dependent synaptic plasticity, thereby contributing to performance improvement after learning. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 00: 000–000, 2018
The Molecular Interplay between Axon Degeneration and Regeneration
Authors: Girouard Marie‐Pier , Bueno Mardja , Julian Victoria , Drake Sienna , Byrne Alexandra B. , Fournier Alyson E. 
Published: July 2018

ABSTRACTNeurons face a series of morphological and molecular changes following trauma and in the progression of neurodegenerative disease. In neurons capable of mounting a spontaneous regenerative response, including invertebrate neurons and mammalian neurons of the peripheral nervous system (PNS), axons regenerate from the proximal side of the injury and degenerate on the distal side. Studies of Wallerian degeneration slow (WldS/Ola) mice have revealed that a level of coordination between the processes of axon regeneration and degeneration occurs during successful repair. Here, we explore how shared cellular and molecular pathways that regulate both axon regeneration and degeneration coordinate the two distinct outcomes in the proximal and distal axon segments. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 00: 000–000, 2018