bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrosynthesis of Hydrogen Peroxide Synergistically Catalyzed by Atomic Co–Nx–C Sites and Oxygen Functional Groups in Noble‐Metal‐Free Electrocatalysts
Authors: Li Bo‐Quan , Zhao Chang‐Xin , Liu Jia‐Ning , Zhang Qiang 
Published: April 2019

AbstractHydrogen peroxide (H2O2) is a green oxidizer widely involved in a vast number of chemical reactions. Electrochemical reduction of oxygen to H2O2 constitutes an environmentally friendly synthetic route. However, the oxygen reduction reaction (ORR) is kinetically sluggish and undesired water serves as the main product on most electrocatalysts. Therefore, electrocatalysts with high reactivity and selectivity are highly required for H2O2 electrosynthesis. In this work, a synergistic strategy is proposed for the preparation of H2O2 electrocatalysts with high ORR reactivity and high H2O2 selectivity. A Co−Nx−C site and oxygen functional group comodified carbon‐based electrocatalyst (named as Co–POC–O) is synthesized. The Co–POC–O electrocatalyst exhibits excellent catalytic performance for H2O2 electrosynthesis in O2‐saturated 0.10 m KOH with a high selectivity over 80% as well as very high reactivity with an ORR potential at 1 mA cm−2 of 0.79 V versus the reversible hydrogen electrode (RHE). Further mechanism study identifies that the Co−Nx−C sites and oxygen functional groups contribute to the reactivity and selectivity for H2O2 electrogeneration, respectively. This work affords not only an emerging strategy to design H2O2 electrosynthesis catalysts with remarkable performance, but also the principles of rational combination of multiple active sites for green and sustainable synthesis of chemicals through electrochemical processes.
Lattice Softening Significantly Reduces Thermal Conductivity and Leads to High Thermoelectric Efficiency
Authors: Hanus Riley , Agne Matthias T. , Rettie Alexander J. E. , Chen Zhiwei , Tan Gangjian , Chung Duck Young , Kanatzidis Mercouri G. , Pei Yanzhong , Voorhees Peter W. , Snyder G. Jeffrey 
Published: April 2019

AbstractThe influence of micro/nanostructure on thermal conductivity is a topic of great scientific interest, particularly to thermoelectrics. The current understanding is that structural defects decrease thermal conductivity through phonon scattering where the phonon dispersion and speed of sound are assumed to remain constant. Experimental work on a PbTe model system is presented, which shows that the speed of sound linearly decreases with increased internal strain. This softening of the materials lattice completely accounts for the reduction in lattice thermal conductivity, without the introduction of additional phonon scattering mechanisms. Additionally, it is shown that a major contribution to the improvement in the thermoelectric figure of merit (zT > 2) of high‐efficiency Na‐doped PbTe can be attributed to lattice softening. While inhomogeneous internal strain fields are known to introduce phonon scattering centers, this study demonstrates that internal strain can modify phonon propagation speed as well. This presents new avenues to control lattice thermal conductivity, beyond phonon scattering. In practice, many engineering materials will exhibit both softening and scattering effects, as is shown in silicon. This work shines new light on studies of thermal conductivity in fields of energy materials, microelectronics, and nanoscale heat transfer.
Janus Graphene: Scalable Self‐Assembly and Solution‐Phase Orthogonal Functionalization
Authors: Jeon Intak , Peeks Martin D. , Savagatrup Suchol , Zeininger Lukas , Chang Sehoon , Thomas Gawain , Wang Wei , Swager Timothy M. 
Published: April 2019

AbstractOrthogonal functionalization of 2D materials by selective assembly at interfaces provides opportunities to create new materials with transformative properties. Challenges remain in realizing controllable, scalable surface‐selective, and orthogonal functionalization. Herein, dynamic covalent assembly is reported that directs the functionalization of graphene surfaces at liquid–liquid interfaces. This process allows facile addition and segregation of chemical functionalities to impart Janus characteristics to graphenes. Specifically, dynamic covalent functionalization is accomplished via Meisenheimer complexes produced by reactions of primary amines with pendant dinitroaromatics attached to graphenes. Janus graphenes are demonstrated to be powerful surfactants that organize at water/organic, water/fluorocarbon, and organic/fluorocarbon liquid interfaces. This approach provides general access to the creation of diverse surfactant materials and promising building blocks for 2D materials.
Dynamics of Antimonene–Graphene Van Der Waals Growth
Authors: Fortin‐Deschênes Matthieu , Jacobberger Robert M. , Deslauriers Charles‐Antoine , Waller Olga , Bouthillier Étienne , Arnold Michael S. , Moutanabbir Oussama 
Published: April 2019

AbstractVan der Waals (vdW) heterostructures have recently been introduced as versatile building blocks for a variety of novel nanoscale and quantum technologies. Harnessing the unique properties of these heterostructures requires a deep understanding of the involved interfacial interactions and a meticulous control of the growth of 2D materials on weakly interacting surfaces. Although several epitaxial vdW heterostructures have been achieved experimentally, the mechanisms governing their synthesis are still nebulous. With this perspective, herein, the growth dynamics of antimonene on graphene are investigated in real time. In situ low‐energy electron microscopy reveals that nucleation predominantly occurs on 3D nuclei followed by a self‐limiting lateral growth with morphology sensitive to the deposition rate. Large 2D layers are observed at high deposition rates, whereas lower growth rates trigger an increased multilayer nucleation at the edges as they become aligned with the Z2 orientation leading to atoll‐like islands with thicker, well‐defined bands. This complexity of the vdW growth is elucidated based on the interplay between the growth rate, surface diffusion, and edges orientation. This understanding lays the groundwork for a better control of the growth of vdW heterostructures, which is critical to their large‐scale integration.
Self‐Cleaning of Interfacial Oil Between Polymer Composites with Porous Zeolite Microparticles and Their Self‐Lubrication Properties
Authors: Ji Zhengjia , Xie Guoxin , Xu Wenhu , Wu Shuai , Zhang Lin , Luo Jianbin 
Published: April 2019

AbstractOil stain self‐cleaning and anti‐adhesion at the contacting interface between planar surfaces is a worldwide challenge and is rarely explored. Inspired by the low adhesion of Coccinella septempunctata to rough nanoporous substrates, it is attempted to reduce adhesion between the contacting interfaces of polymer composite due to the oil stain by constructing porous structures. A facile method is proposed to fabricate porous polymer composites by adding zeolite microparticles. Zeolite microparticles are used as oil cleaner to build the self‐cleaning system. The surface morphology, the mechanical properties, the anti‐adhesion and lubrication properties of the polymer composites are studied. It is suggested that the porous structure possesses self‐cleaning and high mechanical strength in ambient conditions. In addition, the excellent anti‐adhesion behavior can be realized due to the absorption of oil stain of the porous structure in the composite. The results show that the synergistic interaction of the roughness and the oleophilic properties decrease the adhesion between two planar surfaces under the oil stain condition. The present work provides a new route for the development of anti‐adhesion materials.
The Motivation for and Challenges to Scaling Down Organic Field‐Effect Transistors
Authors: Chan Paddy Kwok Leung 
Published: April 2019

AbstractThe development of organic field‐effect transistors (OFETs) in the past few decades has emphasized the carrier mobility of the active layer. It is true that carrier mobility is an important parameter to quantify transistor performance; however, it should not be considered as the only parameter necessary to evaluate the devices. To date, for extraction of the basic electrical properties of the active layers, OFETs fabricated in laboratories are mainly relatively large, with channel lengths ranging from tens to hundreds of micrometers. However, for practical applications, which demand more complicated circuits, scaling down of the OFETs, in particular the channel, is required. In these short‐channel OFETs, the roles of contact resistance, requirements on uniformity, and patterning techniques are all remarkably different from long‐channel devices. The challenges to scaling down OFETs are discussed and some potential approaches to address them.
Does obstetric protection apply to small‐bodied females?: A comparison between small‐bodied Jomon foragers and large‐bodied Yayoi agriculturalists in the prehistoric Japanese archipelago
Authors: Takamuku Hirofumi 
Published: April 2019

AbstractObjectivesThis study examined the relationship between maternal pelvic and body size in the transition from the Middle‐Final Jomon period (c. 5000–3000 BC) to the Middle Yayoi period (c. 400~200 BC to around AD 1) in Japan.MethodsEight measurements, including the left hip bone, articulated pelvis, and femur, were taken from Jomon (females: 37, males: 26) and Yayoi skeletal remains (females: 32, males: 29).ResultsA statistically significant decrease in the anterior diameter of the true pelvic inlet was demonstrated in females from the Jomon to the Yayoi period, but not in males. While significant increases in stature from the Jomon to the Yayoi period were found in both males and females, no significant changes in body mass were seen. The correlation coefficients between true and false pelvic measurements (maximum pelvic height and maximum pelvic breadth) and body size (stature and body mass) suggested few significant relationships between true and false pelvic measurements or body size among the samples, but no significant correlations in small‐bodied Jomon females. Results of principal component analysis using the log‐size and log‐shape variables suggested that the true pelvic size in Jomon and Yayoi females was not correlated with their general pelvic or body size, and there were correlations between sexually dimorphic aspects of true pelvis shape and either the false pelvis or body size in males but not females.ConclusionsThese results suggest that the obstetrical dimensions in small‐bodied Jomon females were maintained for obstetric needs.
Palladium‐Catalyzed Negishi Cross‐Coupling Reaction of Difluoroiodomethane with Arylzinc Reagents
Authors: Nitta Junki , Motohashi Hirotaka , Aikawa Kohsuke , Mikami Koichi 
Published: April 2019

AbstractThe catalytic difluoromethylation of arylzinc reagents with difluoroiodomethane in the presence of Pd2(dba)3/Xantphos is described to produce difluoromethyl products. Mechanistic investigations reveal that the oxidative addition of difluoroiodomethane to [(Xantphos)Pd0] provides trans‐[(Xantphos)PdII(I)CF2H], which is subsequently transformed to cis‐[(Xantphos)PdII(Ph)CF2H] through transmetalation of phenylzinc. Next, reductive elimination occurs (t1/2=44.7 min at −10 °C) to give PhCF2H. The structural changes in [(Xantphos)PdII(Ph)CF2H] from trans to cis facilitates reductive elimination of PhCF2H.
Electron Density Analysis for the H2+ System Confined by Hard Walls: The Chemical Bond Under Extreme Conditions
Authors: Hernández‐Esparza Raymundo , Landeros‐Rivera Bruno , Vargas Rubicelia , Garza Jorge 
Published: April 2019

AbstractFor the first time, the electron density of the H molecule is analyzed when this system is confined by spheroidal walls with an infinite potential. Typically, this system is studied to obtain information of the total energy and its components or to gain insight of some expected values when such a system is squeezed by this kind of confinement. However, this is the first report where the electron density and its derivatives, under the quantum theory of atoms in molecules (QTAIM), are analyzed to study the chemical bond involved with this molecule. This confinement induces an unexpected behavior of the chemical bond and gives an idea about atomic interactions under high pressures, where the QTAIM approach indicates that the chemical bond disappears. For strong confinements, there is a significant contribution of the electron kinetic energy and the nuclear‐electron energy contribution can be neglected. Under this situation, the confined H system is another example where the notion of the topological atom given by the QTAIM is no longer suitable.
Plasmonic Nanocavities Enable Self‐Induced Electrostatic Catalysis
Authors: Climent Clàudia , Galego Javier , Garcia‐Vidal Francisco J. , Feist Johannes 
Published: April 2019

AbstractThe potential of strong interactions between light and matter remains to be further explored within a chemical context. Towards this end herein we study the electromagnetic interaction between molecules and plasmonic nanocavities. By means of electronic structure calculations, we show that self‐induced catalysis emerges without any external stimuli through the interaction of the molecular permanent and fluctuating dipole moments with the plasmonic cavity modes. We also exploit this scheme to modify the transition temperatureT1/2of spin‐crossover complexes as an example of how strong light–matter interactions can ultimately be used to control a materials responses.
A Triskelion‐Shaped Saddle–Helix Hybrid Nanographene
Authors: Cruz Carlos M. , Márquez Irene R. , Castro‐Fernández Silvia , Cuerva Juan M. , Maçôas Ermelinda , Campaña Araceli G. 
Published: April 2019

AbstractA unique rippled nanographene consisting of 52 fused rings is presented in which six out‐of‐plane motifs are fully fused into a triangular aromatic surface with a size of approximately 2.5 nm. Three units of an unprecedented fully lateral π‐extended octabenzo[5]helicene together with three units of saddle‐shaped heptagonal rings are combined in a single structure, leading to a well‐soluble warped nanographene. The two diastereomeric pairs of possible enantiomers were isolated, and their linear, non‐linear, and chiroptical properties were evaluated, revealing outstanding quantum yield and brightness values at low energy, together with good chiroptical responses in both absorption and emission.
The Natural Product Elegaphenone Potentiates Antibiotic Effects against Pseudomonas aeruginosa
Authors: Zhao Weining , Cross Ashley R. , Crowe‐McAuliffe Caillan , Weigert‐Munoz Angela , Csatary Erika E. , Solinski Amy E. , Krysiak Joanna , Goldberg Joanna B. , Wilson Daniel N. , Medina Eva , Wuest William M. , Sieber Stephan A. 
Published: April 2019

AbstractNatural products represent a rich source of antibiotics that address versatile cellular targets. The deconvolution of their targets via chemical proteomics is often challenged by the introduction of large photocrosslinkers. Here we applied elegaphenone, a largely uncharacterized natural product antibiotic bearing a native benzophenone core scaffold, for affinity‐based protein profiling (AfBPP) in Gram‐positive and Gram‐negative bacteria. This study utilizes the alkynylated natural product scaffold as a probe to uncover intriguing biological interactions with the transcriptional regulator AlgP. Furthermore, proteome profiling of a Pseudomonas aeruginosa AlgP transposon mutant provided unique insights into the mode of action. Elegaphenone enhanced the elimination of intracellular P. aeruginosa in macrophages exposed to sub‐inhibitory concentrations of the fluoroquinolone antibiotic norfloxacin.
Electronic Communication across Porphyrin Hexabenzocoronene Isomers
Authors: Martin Max M. , Lungerich Dominik , Haines Philipp , Hampel Frank , Jux Norbert 
Published: April 2019

AbstractSingle‐molecule electronic components (SMECs) are envisioned as next‐generation building blocks in quantum circuit systems. However, challenges such as the reproducibility of the electrode attachment to the individual molecules hamper their fundamental investigation. For our purpose, we introduced quasi optoelectronic electrodes (QOEs) that allow for rapid investigations of the properties and suitability of compounds for molecular electronic devices. In particular, we probed hexa‐peri‐hexabenzocoronene (HBC) as a model system for D6h‐symmetrical nanographenes, with porphyrins as QOEs attached to the periphery. We prepared selectively bis‐porphyrin‐functionalized HBCs with ortho‐, meta‐ and para‐substitution and studied their communication properties, in correlation to the geometrical alignment and size of the system, by electrochemistry and optical spectroscopy. Further insights into structure–property relationships were gained by DFT calculations and X‐ray diffraction analysis.
Selective Sexual Dimorphisms in Musculoskeletal and Cardiopulmonary Pathologic Manifestations and Mortality Incidence in the Tumor Necrosis Factor–Transgenic Mouse Model of Rheumatoid Arthritis
Authors: Bell Richard D. , Wu Emily K. , Rudmann Christopher A. , Forney Megan , Kaiser Claire R. W. , Wood Ronald W. , Chakkalakal Joe V. , Paris Nicole D. , Klose Alanna , Xiao Guang‐Qian , Rangel‐Moreno Javier , Garcia‐Hernandez Maria L. , Ritchlin Christopher T. , Schwarz Edward M. , Rahimi Homaira 
Published: April 2019

ObjectiveTo examine and quantify the sexual dimorphism in pathologic features manifested in the musculoskeletal and cardiopulmonary systems and incidence of mortality in the tumor necrosis factor–transgenic (TNF‐Tg; Tg3647 strain) mouse model of inflammatory erosive arthritis.MethodsKaplan‐Meier survival estimates were determined in male and female Tg3647 mice and sex‐matched wild‐type (WT) littermate mice. Longitudinal and cross‐sectional pathologic outcomes in the musculoskeletal and cardiopulmonary systems were assessed via ultrasound, micro–computed tomography, grip strength measurements, histologic and serologic analyses, flow cytometry, and skeletal muscle physiologic measures.ResultsCompared to male Tg3647 mice (n = 30), female Tg3647 mice (n = 34) had significantly shorter lifespans (P < 0.001) and exhibited the following pathologic features (n = 4–6 per group; P < 0.05 versus male Tg3647 littermates): gross deficits in body mass and muscle weight, early‐onset inflammatory arthritis with severity of end‐stage arthritis that was as severe as that seen in male transgenic mice, and early onset and increased severity of inflammatory interstitial lung disease (ILD). Histologically, the ILD observed in Tg3647 mice was characterized by inflammatory cell accumulation and pulmonary arteriole thickening, which was concomitant with the presence of right ventricular hypertrophy, a feature that was also more severe in the female compared to male Tg3647 mice (P < 0.05). No sexual dimorphisms in TNF‐induced deficient grip strength, axial skeletal growth, or bone loss were found. Globally, the extent of the pathologic changes observed in female Tg3647 mice was greater than that observed in male Tg3647 mice when each group was compared to their sex‐matched WT littermates.ConclusionThese findings indicate that TNF selectively drives the early onset of arthritis and progression of pathologic changes in the cardiopulmonary system in female Tg3647 mice. These results in the Tg3647 mouse identify it as a suitable model to better understand the mechanisms underlying sexual dimorphism and cardiopulmonary disease in the setting of inflammatory arthritis and other connective tissue diseases.
Self‐Assembly Behaviors of a Penta‐Phenylene Maltoside and Its Application for Membrane Protein Study
Authors: Ehsan Muhammad , Kumar Ashwani , Mortensen Jonas S. , Du Yang , Hariharan Parameswaran , Kumar Kaavya K. , Ha Betty , Byrne Bernadette , Guan Lan , Kobilka Brian K. , Loland Claus J. , Chae Pil Seok 
Published: April 2019

AbstractWe prepared an amphiphile with a penta‐phenylene lipophilic group and a branched trimaltoside head group. This new agent, designated penta‐phenylene maltoside (PPM), showed a marked tendency to self‐assembly into micelles via strong aromatic–aromatic interactions in aqueous media, as evidenced by 1H NMR spectroscopy and fluorescence studies. When utilized for membrane protein studies, this new agent was superior to DDM, a gold standard conventional detergent, in stabilizing multiple proteins long term. The ability of this agent to form aromatic–aromatic interactions is likely responsible for enhanced protein stabilization when associated with a target membrane protein.
Triggering Thermally Activated Delayed Fluorescence by Managing the Heteroatom in Donor Scaffolds: Intriguing Photophysical and Electroluminescence Properties
Authors: Konidena Rajendra Kumar , Lee Kyung Hyung , Lee Jun Yeob , Hong Wan Pyo 
Published: April 2019

AbstractEstablishment of the structure–property relationships of thermally activated delayed fluorescence (TADF) materials has become a significant quest for the scientific community. Herein, two new donors, 10H‐benzofuro[3,2‐b]indole (BFI) and 10H‐benzo[4,5]thieno[3,2‐b]indole (BTI), have been developed and integrated with a aryltriazine acceptor to design the green TADF emitters benzofuro[3,2‐b]indol‐10‐yl)‐5‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)benzonitrile (BFICNTrz) and 2‐(10H‐benzo[4,5]thieno[3,2‐b]indol‐10‐yl)‐5‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)benzonitrile (BTICNTrz), respectively. The physicochemical and electroluminescence properties of the compounds were tuned by exchanging the heteroatom in the donor scaffold. Intriguingly, the electronegativity of the heteroatom and the ionization potential of the donor unit played vital roles in control of the singlet–triplet energy splitting and TADF mechanism of the compounds. Both compounds showed similar singlet excited states that originated from the charge transfer (CT) states (1CT), whereas the triplet excited states were tuned by the heteroatom in the donor unit. The origin of phosphorescence in the BTICNTrz emitter was CT emission from the triplet state (3CT), whereas that in the BFICNTrz emitter stemmed from the local triplet excited state (3LE). Consequently, BTICNTrz showed a small singlet–triplet energy splitting of 0.08 eV, compared with 0.26 eV for BFICNTrz. Thus, BTICNTrz showed efficient delayed fluorescence with a high quantum yield and a short delayed exciton lifetime, whereas BFICNTrz displayed weak delayed fluorescence with a relatively long lifetime. Furthermore, a BTICNTrz‐based device exhibited a maximum external quantum efficiency (EQE) of 15.2 % and reduced efficiency roll‐off (12 %) compared with its BFICNTrz‐based counterpart, which showed a maximum EQE of 6.4 % and severe efficiency roll‐off (55 %) at a practical brightness range of 1000 cd m−2. These results demonstrate that the choice of subunit plays a vital role in the design of efficient TADF emitters.
A 3D Iodoplumbate Semiconducting Open Framework with Visible‐light‐induced Photocatalytic Performance
Authors: Ge Bang‐Di , Wei Qi , Sun Ai‐Huan , Lin Chong‐Yang , Duan Xiao‐Fang , Li Jin‐Hua , Wang Guo‐Ming 
Published: April 2019

AbstractEmploying in situ N‐alkylation of the conjugated compound 9,10‐bis(4‐pyridyl)anthracene (bpanth) as structure‐directing agent, a 3D inorganic‐organic hybrid iodoplumbate, [Me2(bpanth)][Pb4I10] (1), was solvothermally prepared. The in situ N‐alkylation of bpanth with alcohols was investigated. 1 features a novel 3D open framework based on an interesting Pb6I24 cluster. UV/Vis spectroscopy analyses indicate that 1 is a potential semiconductor material with a narrow energy gap of 2.06 eV. It exhibits good catalytic activity in the visible‐light‐drived degradation of an organic dye. This work further illustrates that introducing conjugated organic molecules as templates is conducive to achieving semiconducting hybrid halometallates with narrow band gaps.