bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oblate Spheroidal Triboelectric Nanogenerator for All‐Weather Blue Energy Harvesting
Authors: Liu Guanlin , Guo Hengyu , Xu Sixing , Hu Chenguo , Wang Zhong Lin 
Published: May 2019

AbstractTriboelectric nanogenerators (TENGs) provide one of the most promising techniques for large‐scale blue energy harvesting. However, lack of reasonable designs has largely hindered TENG from harvesting energy from both rough and tranquil seas. In this paper, an oblate spheroidal TENG assembled by two novel TENG parts is elaborately designed for both situations. The TENG in the upper part is based on spring steel plates without other substrate materials, which makes it possible to output considerable power in rough seas and occupy small space. The TENG in the lower part consists of two copper‐coated polymer films and a rolling ball which can capture small wave energy from tranquil seas. The working mechanism and output performance are systematically studied. A maximum open‐circuit voltage of 281 V and a short‐circuit current of 76 µA can be achieved by one upper part, enough to charge a commercial capacitor for potential applications. More important, the proposed oblate spheroidal shell not only guarantees high sensitivity of the TENG in the lower part, but also qualifies the TENG with unique self‐stabilization and low consumables for the next generation of TENGs with new structural design toward all‐weather blue energy harvesting.
Novel Graphene Hydrogel/B‐Doped Graphene Quantum Dots Composites as Trifunctional Electrocatalysts for Zn−Air Batteries and Overall Water Splitting
Authors: Tam Tran Van , Kang Sung Gu , Kim Mun Ho , Lee Seung Geol , Hur Seung Hyun , Chung Jin Suk , Choi Won Mook 
Published: May 2019

AbstractHerein, a facile, one‐step hydrothermal route to synthesize novel all‐carbon‐based composites composed of B‐doped graphene quantum dots anchored on a graphene hydrogel (GH‐BGQD) is demonstrated. The obtained GH‐BGQD material has a unique 3D architecture with high porosity and large specific surface area, exhibiting abundant catalytic active sites of B‐GQDs as well as enhanced electrolyte mass transport and ion diffusion. Therefore, the prepared GH‐BGQD composites exhibit a superior trifunctional electrocatalytic activity toward the oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction with excellent long‐term stability and durability comparable to those of commercial Pt/C and Ir/C catalysts. A flexible solid‐state Zn–air battery using a GH‐BGQD air electrode achieves an open‐circuit voltage of 1.40 V, a stable discharge voltage of 1.23 V for 100 h, a specific capacity of 687 mAh g−1, and a peak power density of 112 mW cm−2. Also, a water electrolysis cell using GH‐BGQD electrodes delivers a current density of 10 mA cm−2 at cell voltage of 1.61 V, with remarkable stability during 70 h of operation. Finally, the trifunctional GH‐BGQD catalyst is employed for water electrolysis cell powered by the prepared Zn–air batteries, providing a new strategy for the carbon‐based multifunctional electrocatalysts for electrochemical energy devices.
Selective Aerobic Oxygenation of Tertiary Allylic Alcohols with Molecular Oxygen
Authors: Zhu Bencong , Shen Tao , Huang Xiaoqiang , Zhu Yuchao , Song Song , Jiao Ning 
Published: May 2019

AbstractAerobic epoxidation of tertiary allylic alcohols remains a significant challenge. Reported here is an efficient and highly chemoselective copper‐catalyzed epoxidation and semipinacol rearrangement reaction of tertiary allylic alcohols with molecular oxygen. The solvent 1,4‐dioxane activates dioxygen, thereby precluding the addition of a sacrificial reductant.
Breslow Intermediates from a Thiazolin‐2‐ylidene and Fluorinated Aldehydes: XRD and Solution‐Phase NMR Spectroscopic Characterization
Authors: Paul Mathias , Neudörfl Jörg‐M. , Berkessel Albrecht 
Published: May 2019

AbstractThe first generation and X‐ray diffraction (XRD) analysis of a crystalline Breslow intermediate (BI) derived from a thiazolin‐2‐ylidene, that is, the aromatic heterocycle present in vitamin B1, is reported. Key to success was the combined use of pentafluorobenzaldehyde and a thiazolin‐2‐ylidene carrying an enol‐stabilizing dispersion energy donor as N‐substituent. A so‐called primary intermediate (PI) could be isolated in protonated form (pPI) as well and analyzed by XRD. Furthermore, the first stable BI derived from an aromatic thiazolin‐2‐ylidene and an aliphatic aldehyde (trifluoroacetaldehyde) was prepared and characterized by NMR spectroscopy in solution. When switching to a saturated thiazolidin‐2‐ylidene, reaction with pentafluorobenzaldehyde afforded a new BI in solution (NMR spectroscopy). Attempts to crystallize the latter BI resulted in the isolation of a novel thiazolidin‐2‐ylidene dimer that had undergone rearrangement to a hexahydro[1,4]‐thiazino[3,2‐b]‐1,4‐thiazine.
The Interplay between Structure and Product Selectivity of CO2 Hydrogenation
Authors: Yang Chengsheng , Liu Sihang , Wang Yanan , Song Jimin , Wang Guishuo , Wang Shuai , Zhao Zhi‐Jian , Mu Rentao , Gong Jinlong 
Published: May 2019

AbstractIdentification of the active structure under reaction conditions is of great importance for the rational design of heterogeneous catalysts. However, this is often hampered by their structural complexity. The interplay between the surface structure of Co3O4 and the CO2 hydrogenation is described. Co3O4 with morphology‐dependent crystallographic surfaces presents different reducibility and formation energy of oxygen vacancies, thus resulting in distinct steady‐state composition and product selectivity. Co3O4‐0 h rhombic dodecahedra were completely reduced to Co0 and CoO, which presents circa 85 % CH4 selectivity. In contrast, Co3O4‐2 h nanorods were partially reduced to CoO, which exhibits a circa 95 % CO selectivity. The crucial role of the Co3O4 structure in determining the catalytic performance for higher alcohol synthesis over CuCo‐based catalysts is demonstrated. As expected, Cu/Co3O4‐2 h shows nine‐fold higher ethanol yield than Cu/Co3O4‐0 h owing to the inhibition for methanation.
Investigation of an Unusual Crystal Habit of Hydrochlorothiazide Reveals Large Polar Enantiopure Domains and a Possible Crystal Nucleation Mechanism
Authors: Thomas Sajesh P. , Grosjean Arnaud , Flematti Gavin R. , Karton Amir , Sobolev Alexandre N. , Edwards Alison J. , Piltz Ross O. , Iversen Bo B. , Koutsantonis George A. , Spackman Mark A. 
Published: May 2019

AbstractThe observation of an unusual crystal habit in the common diuretic drug hydrochlorothiazide (HCT), and identification of its subtle conformational chirality, has stimulated a detailed investigation of its crystalline forms. Enantiomeric conformers of HCT resolve into an unusual structure of conjoined enantiomorphic twin crystals comprising enantiopure domains of opposite chirality. The purity of the domains and the chiral molecular conformation are confirmed by spatially revolved synchrotron micro‐XRD experiments and neutron diffraction, respectively. Macroscopic inversion twin symmetry observed between the crystal wings suggests a pseudoracemic structure that is not a solid solution or a layered crystal structure, but an unusual structural variant of conglomerates and racemic twins. Computed interaction energies for molecular pairs in the racemic and enantiopure polymorphs of HCT, and the observation of large opposing unit‐cell dipole moments for the enantiopure domains in these twin crystals, suggest a plausible crystal nucleation mechanism for this unusual crystal habit.
Duplex‐gesteuerte Umfaltung in neuartige G‐Quadruplex‐(3+1)‐ Hybridkonformationen
Authors: Karg Beatrice , Mohr Swantje , Weisz Klaus 
Published: May 2019

AbstractEs konnte gezeigt werden, dass sich ein DNA‐Oligonukleotid der Sequenz d(GCGTG3TCAG3TG3TG3ACGC) mit kurzen, komplementären Überhangsequenzen am 5′‐ und 3′‐Ende in drei unterschiedliche Quadruplexspezies faltet. Dagegen bildet das entsprechende Oligomer ohne Basenkomplementarität der beiden Überhangsequenzen nur eine einzige parallele G‐Quadruplexstruktur. Über einen Vergleich von NMR‐Spektren der polymorphen Probe mit genau definierten G‐Quadruplexen, die über einen gezielten Einbau von syn‐präferierenden 8‐Bromguanosin‐Analoga erhalten wurden, konnten die drei koexistierenden Quadruplexstrukturen eindeutig zugeordnet und strukturell charakterisiert werden. Dabei liegen neben der parallelen Form zwei weitere (3+1)‐Hybridstrukturen vor. Diese weisen mit einem Lateralloop, gefolgt von zwei Propellerloops, eine bisher experimentell noch nicht eindeutig nachgewiesene Looparchitektur auf. Beide Hybridquadruplexe haben die gleiche Topologie und unterscheiden sich nur in den anti→syn‐Abfolgen entlang der G‐Trakte sowie den Stapelwechselwirkungen zwischen den G‐Tetraden.
Deracemisierung von α‐verzweigten Carbonsäuren durch katalytische asymmetrische Protonierung von Bis‐Silylketenacetalen mit Wasser oder Methanol
Authors: Mandrelli Francesca , Blond Aurélie , James Thomas , Kim Hyejin , List Benjamin 
Published: May 2019

AbstractWir beschreiben eine hochenantioselektive katalytische Protonierung von Bis‐Silylketenacetalen. Unsere Methode liefert α‐verzweigte Carbonsäuren, einschließlich nichtsteroidaler entzündungshemmender Arylpropionsäuren wie Ibuprofen, in hoher Enantiomerenreinheit und Ausbeute. Der Prozess kann in eine generelle Deracemisierung von α‐verzweigten Carbonsäuren integriert werden, die eine doppelte Deprotonierung und Silylierung gefolgt von der katalytisch asymmetrischen Protonierung umfasst.
Structure of the Au23−xAgx(S‐Adm)15 Nanocluster and Its Application for Photocatalytic Degradation of Organic Pollutants
Authors: Liu Chao , Ren Xiuqing , Lin Feng , Fu Xuemei , Lin Xinzhang , Li Tao , Sun Keju , Huang Jiahui 
Published: May 2019

AbstractLigands play an important role in determining the atomic arrangement within the metal nanoclusters. Here, we report a new nanocluster [Au23−xAgx(S‐Adm)15] protected by bulky adamantanethiol ligands which was obtained through a one‐pot synthesis. The total structure of [Au23−xAgx(S‐Adm)15] comprises an Au13−xAgx icosahedral core, three Au3(SR)4 units, and one AgS3 staple motif in contrast to the 15‐atom bipyramidal core previously seen in [Au23−xAgx(SR)16]. UV/Vis spectroscopy indicates that the HOMO–LUMO gap of [Au23−xAgx(S‐Adm)15] is 1.5 eV. DFT calculations reveal that [Au19Ag4(S‐Adm)15] is the most stable structure among all structural possibilities. Benefitting from Ag doping, [Au23−xAgx(S‐Adm)15] exhibits drastically improved photocatalytic activity for the degradation of rhodamine B (RhB) and phenol under visible‐light irradiation compared to Au23 nanoclusters.
Duplex‐Guided Refolding into Novel G‐Quadruplex (3+1) Hybrid Conformations
Authors: Karg Beatrice , Mohr Swantje , Weisz Klaus 
Published: May 2019

AbstractThe oligomer d(GCGTG3TCAG3TG3TG3ACGC) with short complementary flanking sequences at the 5′‐ and 3′‐ends was shown to fold into three different DNA G‐quadruplex species. In contrast, a corresponding oligomer that lacks base complementarity between the two overhang sequences folds into a single parallel G‐quadruplex. The three coexisting quadruplex structures were unambiguously identified and structurally characterized through detailed spectral comparisons with well‐defined G‐quadruplexes formed upon the deliberate incorporation of syn‐favoring 8‐bromoguanosine analogues into specific positions of the G‐core. Two (3+1) hybrid structures coexist with the parallel fold and feature a novel lateral–propeller–propeller loop architecture that has not yet been confirmed experimentally. Both hybrid quadruplexes adopt the same topology and only differ in their pattern of anti→syn transitions and tetrad stackings.
Green synthesis and characterizations of Nickel oxide nanoparticles using leaf extract of Rhamnus virgata and their potential biological applications
Authors: Iqbal Javed , Abbasi Banzeer Ahsan , Mahmood Tariq , Hameed Safia , Munir Akhtar , Kanwal Sobia 
Published: May 2019

In the present report, Nickel oxide nanoparticles (NiONPs) were synthesized using Rhamnus virgata (Roxb.) (Family: Rhamnaceae) as a potential stabilizing, reducing and chelating agent. The formation, morphology, structure and other physicochemical properties of resulting NiONPs were characterized by Ultra violet spectroscopy, X‐ray diffraction (XRD), Fourier Transform Infrared analysis (FTIR), Scanning electron microscopy (SEM), Energy‐dispersive‐spectroscopy (EDS), Transmission electron microscopy (TEM), Raman spectroscopy and dynamic light scattering (DLS). Detailed in vitro biological activities revealed significant therapeutic potential for NiONPs. The antimicrobial efficacy of biogenic NiONPs was demonstrated against five different gram positive and gram negative bacterial strains. Klebsiella pneumoniae and Pseudomonas aeruginosa (MIC: 125 μg/mL) were found to be the least susceptible and Bacillus subtilis (MIC: 31.25 μg/mL) was found to be the most susceptible strain to NiONPs. Biogenic NiONPs were reported to be highly potent against HepG2 cells (IC50: 29.68 μg/ml). Moderate antileishmanial activity against Leishmania tropica (KMH23) promastigotes (IC50: 10.62 μg/ml) and amastigotes (IC50: 27.58 μg/ml) cultures are reported. The cytotoxic activity was studied using brine shrimps and their IC50 value was recorded as 43.73 μg/ml. For toxicological assessment, NiONPs were found compatible towards human RBCs (IC50: > 200 μg/ml) and macrophages (IC50: > 200 μg/ml), deeming particles safe for various applications in nanomedicines. Moderate antioxidant activities: total antioxidant capacity (TAC) (51.43%), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) activity (70.36%) and total reducing power (TRP) (45%) are reported for NiONPs. In addition, protein kinase and alpha amylase inhibition assays were also performed. Our results concluded that Rhamnus virgata synthesized NiONPs could find important biomedical applications with low cytotoxicity to normal cells.
Antidiabetic properties of dietary phenolic compounds: Inhibition effects on α‐amylase, aldose reductase, and α‐glycosidase
Authors: Demir Yeliz , Durmaz Lokman , Taslimi Parham , Gulçin İlhami 
Published: May 2019

AbstractAldose reductase (AR), α‐amylase, and α‐glycosidase are vital enzymes to prevent diabetic complications. Here, AR was purified from sheep kidney using elementary methods with 111.11‐purification fold and with 0.85% purification yield. The interactions between some phenolic compounds and the AR, α‐glycosidase, and α‐amylase enzyme were determined. It was found that phenolic compounds exhibit potential inhibitor properties for these enzymes. For α‐amylase, studied phenolic compounds showed IC50 values in the range of 601.56–2,067.78 nM. For α‐glycosidase, Ki values were found in the range of 169.25 ± 27.22–572.88 ± 106.76 nM. For AR, Ki values in the range of 8.48 ± 0.56–43.26 ± 7.63 µM. However, genistein showed the best inhibition effect toward AR and α‐glycosidase, but delphinidin chloride exhibited the best inhibition effect against α‐amylase enzyme. We determined that all compounds showed noncompetitive inhibition effect against AR and α‐glycosidase. Also, studied phenolic compounds may be useful in the prevention or treatment of diabetic complications.
Modulatory effects of curcumin on heat shock proteins in cancer: A promising therapeutic approach
Authors: Forouzanfar Fatemeh , Barreto George , Majeed Muhammed , Sahebkar Amirhossein 
Published: May 2019

AbstractCancer metastasis represents a multistep process, including alteration of cell adhesion/motility in the microenvironment and sustained angiogenesis, which is essential for supporting cancer growth in tissues that are distant from the primary tumor. There is growing evidence suggesting that heat shock proteins (HSPs) (also known as heat stress proteins), which constitute a family of stress‐inducible proteins, may be involved in the pathogenesis of cancer. Curcumin (diferuloylmethane) is a potent anti‐inflammatory, antioxidant, antimicrobial, and antitumor agent. Curcumin has been shown to regulate different members of HSPs including HSP27, HSP40, HSP60, HSP70, and HSP90 in cancer. Here, we present extent findings suggesting that curcumin may act as a potential therapeutic agent for the treatment of cancer through its regulation of HSPs.
Development of a microchannel emulsification process for pancreatic beta cell encapsulation
Authors: Bitar Christina M.E. , Markwick Karen E. , Treľová Dušana , Kroneková Zuzana , Pelach Michal , Selerier Chloé M.O. , Dietrich James , Lacík Igor , Hoesli Corinne A. 
Published: May 2019

AbstractIn this study, we developed a high‐throughput microchannel emulsification process to encapsulate pancreatic beta cells in monodisperse alginate beads. The process builds on a stirred emulsification and internal gelation method previously adapted to pancreatic cell encapsulation. Alginate bead production was achieved by flowing a 0.5–2.5% alginate solution with cells and CaCO3 across a 1‐mm thick polytetrafluoroethylene plate with 700 × 200 μm rectangular straight‐through channels. Alginate beads ranging from 1.5–3 mm in diameter were obtained at production rates exceeding 140 mL/hr per microchannel. Compared to the stirred emulsification process, the microchannel emulsification beads had a narrower size distribution and demonstrated enhanced compressive burst strength. Both microchannel and stirred emulsification beads exhibited homogeneous profiles of 0.7% alginate concentration using an initial alginate solution concentration of 1.5%. Encapsulated beta cell viability of 89 ± 2% based on live/dead staining was achieved by minimizing the bead residence time in the acidified organic phase fluid. Microchannel emulsification is a promising method for clinical‐scale pancreatic beta cell encapsulation as well as other applications in the pharmaceutical, food, and cosmetic industries.
An optimization on water wave diffraction approximation based on wave packets
Authors: Yang Zhongyao , Liu Shiguang 
Published: May 2019

AbstractThis paper proposes a novel approach for diffraction approximation in two‐dimensional water wave simulation. Our method is based on wave packets, which ensures unconditionally stability. We introduce the Green function in order to generate diffraction patterns that are used to judge whether our method can produce realistic diffraction effects. This method also implements propagation direction optimization for diffractive wave packets to handle the efficiency problem existed in the state‐of‐the‐art approach. Various results indicate that our new method can produce more appealing diffractive effects than current particle‐based approaches. Besides, from the efficiency perspective, compared to current approaches, our implementation greatly enhances the computational efficiency for scenes with high curvature obstacle boundaries.
Co‐MOF‐Derived Hierarchical Mesoporous Yolk‐shell‐structured Nanoreactor for the Catalytic Reduction of Nitroarenes with Hydrazine Hydrate
Authors: Yuan Man , Zhang Hongbo , Yang Chen , Wang Fanhao , Dong Zhengping 
Published: May 2019

AbstractPorous nanoreactors demonstrate immense potential for applications in heterogeneous catalysis due to their excellent mass‐transfer performance and stability. The design of a simple, universal strategy for fabricating nanoreactor catalysts is of significance for organic transformation. In this study, a nanoreactor with a hierarchical mesoporous yolk‐shell structure was successfully prepared by the high‐temperature carbonization of a ZIF‐67@polymer composite. The core of the resultant Co@ZDC@mC material comprised Co NPs anchored in the ZIF‐67‐derived carbon framework, while the shell comprised resin‐polymer‐derived mesoporous carbon. The as‐obtained Co@ZDC@mC‐700 catalyst enriched reactants, efficiently catalyzed the reaction in the core, and permitted the desorption of the product from the nanoreactor. In the catalytic reduction of nitrobenzene with N2H4⋅H2O, Co@ZDC@mC‐700 exhibited superior catalytic efficiency (TOF=1136.3 h−1). In addition, Co@ZDC@mC‐700 exhibited excellent performance for the catalytic reduction of various functionalized nitroarenes, as well as good reusability and recyclability. Hence, a simple, useful approach for fabricating a metal‐organic‐framework‐derived non‐noble metal‐based yolk‐shell nanoreactor for effective catalytic transformation is proposed.
Morphology Control Synthesis of ZIF‐8 as Highly Efficient Catalyst for the Cycloaddition of CO2 to Cyclic Carbonate
Authors: Hu Lihua , Yan Zongcheng , Mo Xiaohong , Peng Xiong , Chen Li 
Published: May 2019

AbstractMorphology control synthesis of zeolitic imidazolate frameworks (ZIFs) is very important to understand its morphology, structure, and catalytic property relationships. Herein, morphology control synthesis of ZIF‐8 was achieved through an efficient and environmentally friendly one‐pot heating strategy. Different sophisticated ZIF‐8, such as solid spheres, hollow spheres, hierarchical particles, and stackable particles, were obtained by using different surfactants as templates. The sophisticated ZIF‐8 can be employed directly as a catalyst for cycloaddition reaction between CO2 and styrene oxide. The high specific surface areas and most abundant acid‐base sites are account for the superior catalytic performance of ZIF‐8 solid spheres, and the rich mesopores provides channels for the mass transfer of large reactants or product molecules, facilitating the accessibility of reactive sites and increasing catalytic activity. ZIF‐8 solid spheres showed enhanced catalytic activity and excellent recyclability and are thus potential heterogeneous catalysts in various catalytic reactions.
Suppressing Nickel Dissolution in Ni‐rich Layered Oxide Cathodes Using NiF2 as Electrolyte Additive
Authors: Zhang Jinping , Xue Longlong , Li Yunjiao , Lei Tongxing , Deng Shiyi , Chen Yongxiang , Zhu Jie , Wang Shilei , Guo Jia 
Published: May 2019

AbstractThe dissolution of transition metals is the main reason for the capacity fading and structural degradation of Ni‐rich cathode materials. In this work, NiF2 is used as functional electrolyte additive for the first time to improve the performance of LiNi0.6Co0.2Mn0.2O2 cathodes by the chemical‐equilibrium principle. The suppression of transition‐metal dissolution, especially Ni, is proved by energy disperse spectroscopy and inductively coupled plasma analyses. The NiF2 additive can stabilize the cathode structure by relieving the dissolution of transition metals, which is confirmed by morphology and structure analyses. Moreover, the NiF2 additive also reduces side reactions of the cell, which is verified by self‐discharge tests and coulombic efficiency analysis. As a result, the addition of 100 ppm NiF2 elevates the capacity retention of the Li/NCM622 half‐cell from 69.53 to 79.67 % after 100 cycles, and the 100 ppm NiF2‐containing cathode delivers an initial capacity of 174.0 mAh g−1 even at 8 C after 50 cycles.
Infrared Spectroscopy of Size‐Selected Hydrated Carbon Dioxide Radical Anions CO2.−(H2O)n (n=2–61) in the C−O Stretch Region
Authors: Herburger Andreas , Ončák Milan , Siu Chi‐Kit , Demissie Ephrem G. , Heller Jakob , Tang Wai Kit , Beyer Martin K. 
Published: May 2019

AbstractUnderstanding the intrinsic properties of the hydrated carbon dioxide radical anions CO2.−(H2O)n is relevant for electrochemical carbon dioxide functionalization. CO2.−(H2O)n (n=2–61) is investigated by using infrared action spectroscopy in the 1150–2220 cm−1 region in an ICR (ion cyclotron resonance) cell cooled to T=80 K. The spectra show an absorption band around 1280 cm−1, which is assigned to the symmetric C−O stretching vibration νs. It blueshifts with increasing cluster size, reaching the bulk value, within the experimental linewidth, for n=20. The antisymmetric C−O vibration νas is strongly coupled with the water bending mode ν2, causing a broad feature at approximately 1650 cm−1. For larger clusters, an additional broad and weak band appears above 1900 cm−1 similar to bulk water, which is assigned to a combination band of water bending and libration modes. Quantum chemical calculations provide insight into the interaction of CO2.− with the hydrogen‐bonding network.