bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iron(III) Chloride/Dialkyl Diselenides‐Promoted Cascade Cyclization of ortho‐Diynyl Benzyl Chalcogenides
Authors: do Carmo Pinheiro Roberto , Back Davi F. , Zeni Gilson 
Published: February 2019

AbstractTreatment of ortho‐diynyl benzyl chalcogenides with a mixture of iron(III) chloride and diorganyl diselenides led to functionalized chalcogen isochromene‐fused chalcogenophene derivatives. The reaction parameters were studied and the results indicated that the reaction of ortho‐ diynyl benzyl chalcogenides (0.25 mmol) with iron(III) chloride hexahydrate (2.0 equiv.) and diorganyl diselenide (2 equiv.) at reflux of dichloroethane was the best condition to give the products in 40–83% yields. The results support the idea that a mixture of iron salts and diorganyl diselenides has a dual action, promoting the cyclization and introducing a new functionalization at the 3‐position of isochalcogenochromenes. The methodology was highly regioselective, giving the product via 6‐endo‐dig mode followed by a second cyclization via 5‐endo‐dig mode.magnified image
Wafer Scale Mapping and Statistical Analysis of Radio Frequency Characteristics in Highly Uniform CVD Graphene Transistors
Authors: Tian Mengchuan , Hu Ben , Yang Haifang , Tang Chengchun , Wang Mengfei , Gao Qingguo , Xiong Xiong , Zhang Zhenfeng , Li Tiaoyang , Li Xuefei , Gu Changzhi , Wu Yanqing 
Published: February 2019

AbstractRadio frequency (RF) transistor based on graphene has attracted tremendous research efforts in the past few years. Despite the fact that such material is developed on a wafer‐scale level, the majority of reported high performance of individual transistors is limited to individual or a few devices. As a result, the electronic uniformity and stability study on a large number of transistors remain unexplored especially for RF performance, which are the most critical factors for any practical applications. In this work, a comprehensive statistical analysis of the uniformity of DC and RF characteristics simultaneously for hundreds of transistors fabricated from transferred large‐area CVD‐grown graphene in a 4‐inch HfSiO/Si wafer is carried out for the first time. For devices with the same gate length of 0.8 µm, the coefficient of variation (CV) for Dirac point voltage and extrinsic peak transconductance is only 0.07 and 0.03, respectively. In addition, the intrinsic f
T*L
g is high up to about 20 GHz · μm, which is among the best value for the graphene RF transistors. More importantly, the CV for the as‐measured f
max/f
T is as low as 0.11, indicating highly uniform RF characteristics across the 4‐inch wafer.
Significantly Increased Photoresponsivity of WSe2‐Based Transistors through Hybridization with Gold‐Tetraphenylporphyrin as Efficient n‐Type Dopant
Authors: Lee Dong Seop , Kim Jun Young , Shin Dae Yong , Lee Yongjun , Kim Jeongyong , Lee Suk Joong , Joo Jinsoo 
Published: February 2019

AbstractThe control of electrical and optical characteristics of 2D transition‐metal dichalcogenides (TMDCs) through charge doping is essential to optimize the performances of optoelectronic devices based on TMDCs. In this study, a few‐layer tungsten diselenide (WSe2) is hybridized with organic gold(III)‐tetraphenylporphyrin (Au‐TPP) using a simple drop‐casting method. Nanoscale optical characteristics, measured by laser confocal microscopy, reveal that the photoluminescence intensity and exciton lifetime of Au‐TPP decrease after the hybridization with WSe2, which suggests the charge transfer from Au‐TPP to WSe2. For optoelectronic applications, photoresponsive field‐effect transistors (FETs) based on pristine WSe2 and WSe2/Au‐TPP hybrids are fabricated and compared. After the hybridization with Au‐TPP, the charge transport characteristics of the WSe2‐based FETs change to severe n‐type characteristics including a negative shift of the threshold voltage and increase in electron mobility. Significantly enhanced photoresponsivities (up to 310 times) are observed for the WSe2/Au‐TPP‐based FETs owing to their efficient light absorption and charge transfer from Au‐TPP to WSe2.
Low‐Temperature‐Processed Colloidal Quantum Dots as Building Blocks for Thermoelectrics
Authors: Nugraha Mohamad I. , Kim Hyunho , Sun Bin , Haque Md Azimul , de Arquer Francisco Pelayo Garcia , Villalva Diego Rosas , El‐Labban Abdulrahman , Sargent Edward H. , Alshareef Husam N. , Baran Derya 
Published: February 2019

AbstractColloidal quantum dots (CQDs) are demonstrated to be promising materials to realize high‐performance thermoelectrics owing to their low thermal conductivity. The most studied CQD films, however, are using long ligands that require high processing and operation temperature (>400 °C) to achieve optimum thermoelectric performance. Here the thermoelectric properties of CQD films cross‐linked using short ligands that allow strong inter‐QD coupling are reported. Using the ligands, p‐type thermoelectric solids are demonstrated with a high Seebeck coefficient and power factor of 400 μV K−1 and 30 µW m−1 K−2, respectively, leading to maximum ZT of 0.02 at a lower measurement temperature (<400 K) and lower processing temperature (<300 °C). These ligands further reduce the annealing temperature to 175 °C, significantly increasing the Seebeck coefficient of the CQD films to 580 μV K−1. This high Seebeck coefficient with a superior ZT near room temperature compared to previously reported high temperature‐annealed CQD films is ascribed to the smaller grain size, which enables the retainment of quantum confinement and significantly increases the hole effective mass in the films. This study provides a pathway to approach quantum confinement for achieving a high Seebeck coefficient yet strong inter‐QD coupling, which offers a step toward low‐temperature‐processed high‐performance thermoelectric generators.
Ultrafine Copper Nanopalm Tree‐Like Framework Decorated with Iron Oxide for Li‐Ion Battery Anodes with Exceptional Rate Capability and Cycling Stability
Authors: Seok Jae Young , Lee Jaehak , Park Jung Hwan , Yang Minyang 
Published: February 2019

AbstractUltrafine copper nanopalm tree‐like frameworks conformally decorated with iron oxide (Cu NPF@Fe2O3) are prepared by a facile electrodeposition method utilizing bromine ions as unique anisotropic growth catalysts. The formation mechanism and control over Cu growth are comprehensively investigated under various conditions to provide a guideline for fabricating a Cu nanoarchitecture via electrochemical methods. The optimized Cu NPFs exhibit ultrathin (<90 nm) and elongated (2–50 µm) branches with well‐interconnected and entangled features, which result in highly desirable attributes such as a large specific surface area (≈6.97 m2 g−1), free transfer pathway for Li+, and high electrical conductivity. The structural advantages of Cu NPF@Fe2O3 enhance the electrochemical kinetics, providing large reactivity, fast Li+/electron transfer, and structural stability during cycling, that lead to superior electrochemical Li storage performance. The resulting Cu NPF@Fe2O3 demonstrates a high specific capacity (919.5 mAh g–1 at 0.1 C), long‐term stability (801.1 mAh g–1 at 2 C, ≈120% retention after 500 cycles), and outstanding rate capability (630 mAh g–1 at 10 C).
Charge‐Transfer States at Organic–Organic Interfaces: Impact of Static and Dynamic Disorders
Authors: Zheng Zilong , Tummala Naga Rajesh , Wang Tonghui , Coropceanu Veaceslav , Brédas Jean‐Luc 
Published: February 2019

AbstractMolecular dynamics simulations are combined with density functional theory calculations to evaluate the impact of static and dynamic disorders on the energy distribution of charge‐transfer (CT) states at donor–acceptor heterojunctions, such as those found in the active layers of organic solar cells. It is shown that each of these two disorder components can be partitioned into contributions related to the energetic disorder of the transport states and to the disorder associated with the hole–electron electrostatic interaction energies. The methodology is applied to evaluate the energy distributions of the CT states in representative bulk heterojunctions based on poly‐3‐hexyl‐thiophene and phenyl‐C61‐butyric‐acid methyl ester. The results indicate that the torsional fluctuations of the polymer backbones are the main source of both static and dynamic disorders for the CT states as well as for the transport levels. The impact of static and dynamic disorders on radiative and nonradiative geminate recombination processes is also discussed.
Interfacial Charge Modulation: An Efficient Strategy for Boosting Spatial Charge Separation on Semiconductor Photocatalysts
Authors: Tao Xiaoping , Gao Yuying , Wang Shengyang , Wang Xiaoyu , Liu Yang , Zhao Yue , Fan Fengtao , Dupuis Michel , Li Rengui , Li Can 
Published: February 2019

AbstractSurface modulation via injection or extraction of charge carriers in microelectric devices has been used to tune the energy band alignment for desired electrical and optical properties, yet not well recognized in photocatalysis field. Here, taking semiconductor bismuth tantalum oxyhalides (Bi4TaO8X) as examples, chemically inactive molybdenum oxide (MoO3) with a large work function is introduced to qualitatively tune the properties of interfacial charges, achieving an evidently enhanced upward band bending and intensive built‐in electric field. Such a simple charge modulation exhibits a remarkable improvement in photocatalytic water oxidation, reaching an apparent quantum efficiency of 25% at the input wavelength of 420 nm. The validity and generality of surface charge modulating strategy are further demonstrated using other semiconductors (e.g., C3N4) and decorators (e.g., V2O5). The findings not only provide a promising strategy for rationally manipulating the interfacial built‐in electric field in photocatalysis but also pave the way to learn from microelectronic technologies to construct artificial photosynthesis systems for solar energy conversion.
Polypharmacy in elderly cancer patients: Challenges and the way clinical pharmacists can contribute in resource‐limited settings
Authors: Shrestha Sunil , Shrestha Sudip , Khanal Saval 
Published: February 2019

AbstractThe aim of this study was to address the problems associated with polypharmacy in elderly cancer patients and to highlight the role of pharmacists in such cases in resource‐limited settings. A narrative review of existing literature was performed to summarize the evidence regarding the impact of polypharmacy in elderly cancer patients and the pharmaceutical strategies to manage it. This review emphasizes the significance of polypharmacy, which is often ignored in real clinical practice. Polypharmacy in the elderly cancer population is mainly due to: chemotherapy with one or more neoplastic agents for cancer treatment, treatment for adverse drug reactions due to neoplastic agents, the patient's comorbid conditions, or drug interactions. The role of the clinical pharmacist in specialized oncology hospitals or oncology departments of tertiary care hospitals is well established; however, this is not the case in many developing countries. A clinical pharmacist can contribute to solving the problems associated with polypharmacy by identifying the risks associated with polypharmacy and its management in resource‐limited settings. As in many developed countries, the involvement of a clinical pharmacist in cancer care for elderly patients may play a vital role in the recognition and management of polypharmacy‐related problems. Further research can be conducted to support this role.
Counter‐rotating vortex shedding generated by acoustic excitations in confined mixing layers
Authors: Zhao Wei , Wang Guiren 
Published: February 2019

AbstractUltrafast mixing enhancement has been realized in confined mixing layers at an optimal forcing frequency, under which the flow exhibits the strongest mixing. The fast mixing is accompanied by the so‐called counter‐rotating vortices (CRVs). In this investigation, by using particle imaging velocimetry (PIV) and laser‐induced fluorescence, the conditions of generating CRVs in confined mixing layers are theoretically and experimentally investigated. To generate CRVs, (a) the acoustic particle displacement must be larger than the summation of the curvature radius of the trailing edge and the thickness of the Stokes layer, and (b) the temporal derivative term of the vorticity equation should be larger than the convective term of the mean vorticity generated by the mean flow. This study enhances our understanding on vortex shedding dynamics and enables novel designs of fast mixers for continuous operations in process industry.
Higher urate in LRRK2 mutation carriers resistant to Parkinson disease
Authors: Bakshi Rachit , Macklin Eric A. , Logan Robert , Zorlu Musab M. , Xia Ning , Crotty Grace F. , Zhang Ellen , Chen Xiqun , Ascherio Alberto , Schwarzschild Michael A. 
Published: February 2019

Objective
LRRK2 mutations, the most common genetic cause of Parkinson disease (PD), display incomplete penetrance, indicating the importance of other genetic and environmental influences on disease pathogenesis in LRRK2 mutation carriers. The present study investigates whether urate, an antioxidant, Nrf2 activator, and inverse risk factor for idiopathic PD, is one such candidate biomarker of PD risk modulation in pathogenic LRRK2 mutation carriers.MethodsBanked plasma samples or urate levels were obtained for 3 cohorts of age‐ and sex‐matched subjects with and without a known LRRK2 mutation in PD and unaffected controls to conduct a pilot study of 192 subjects from the LRRK2 Cohort Consortium (LCC) and 2 validation studies of 380 additional subjects from the LCC and 922 subjects from the Parkinson's Progression Markers Initiative. Urate levels were compared by multiple regression between subjects with and without a PD diagnosis conditional on LRRK2 status, controlling for age and sex.ResultsNonmanifesting LRRK2 mutation carriers had significantly higher levels of urate than those who developed PD in each of the 3 independent cohorts. A meta‐analysis demonstrated an adjusted mean difference of 0.62 mg/dL (p < 0.001), with similar results for separate assessments of women (p < 0.02) and men (p < 0.001). A 2 mg/dL increment in urate concentration decreased the odds of having PD by approximately 50% (odds ratio = 0.48, p = 0.004).InterpretationThese findings identify and substantiate urate as a biomarker of resistance to PD among LRRK2 mutation carriers. Ann Neurol 2019;85:593–599
C1‐Linked Spirobifluorene Dimers: Pure Hydrocarbon Hosts for High‐Performance Blue Phosphorescent OLEDs
Authors: Sicard Lambert J. , Li Hong‐Cheng , Wang Qiang , Liu Xiang‐Yang , Jeannin Olivier , Rault‐Berthelot Joëlle , Liao Liang‐Sheng , Jiang Zuo‐Quan , Poriel Cyril 
Published: February 2019

AbstractReported here are C1‐linked spiro‐bifluorene dimers. A comprehensive study is carried out to analyze the electronic properties of these highly twisted structures. This work shows that the C1‐position enables the design of pure hydrocarbon materials, with a high triplet energy, for hosting blue phosphors in efficient phosphorescent OLEDs (PhOLEDs). To date, this work describes the highest performance of blue PhOLEDs ever reported for pure hydrocarbons (external quantum efficiency of ca. 23 %), thus highlighting the potential of the C1‐spirobifluorene scaffold in organic electronics.
Ist ein gebogener Kristall immer noch ein Einkristall?
Authors: Commins Patrick , Karothu Durga Prasad , Naumov Panče 
Published: February 2019

AbstractDie Erwähnung des Wortes “Kristall” ruft beim Betrachter Bilder von Mineralien, Edelsteinen und Gesteinen hervor, die alle unvermeidlich solide, harte und langlebige Objekte mit klar definierten glatten Flächen und geraden Kanten sind. Mit der Entdeckung in der ersten Hälfte des 20. Jahrhunderts, dass viele molekulare Kristalle weich sind und ähnlich wie Gummi oder Kunststoff verformt werden können, entwickelte sich die Auffassung, dass das, was einst als Kristall galt, heute einer neuen formalen Definition bedarf. Die scheinbar naive Frage im Titel dieses Aufsatzes hat keine einfache Antwort. Wir diskutieren die Auswirkungen der elastischen und plastischen Verformung von Molekülkristallen auf die Beugungssignatur als primären Nachweis für den Grad ihrer Kristallinität. In den meisten Fällen gilt die allgemein akzeptierte Definition eines Kristalls auch für elastisch und plastisch verformte Kristalle. Sofern keine signifikante oder vollständige physikalische Trennung des Kristalls während der Verformung vorliegt, können sie sicher als (verformte) Einkristalle mit hoher Fehlerdichte betrachtet werden.
Successful Decontamination of 99TcO4− in Groundwater at Legacy Nuclear Sites by a Cationic Metal‐Organic Framework with Hydrophobic Pockets
Authors: Sheng Daopeng , Zhu Lin , Dai Xing , Xu Chao , Li Peng , Pearce Carolyn I. , Xiao Chengliang , Chen Jing , Zhou Ruhong , Duan Tao , Farha Omar K. , Chai Zhifang , Wang Shuao 
Published: February 2019

Abstract99Tc contamination at legacy nuclear sites is a serious and unsolved environmental issue. The selective remediation of 99TcO4− in the presence of a large excess of NO3− and SO42− from natural waste systems represents a significant scientific and technical challenge, since anions with a higher charge density are often preferentially sorbed by traditional anion‐exchange materials. We present a solution to this challenge based on a stable cationic metal‐organic framework, SCU‐102 (Ni2(tipm)3(NO3)4), which exhibits fast sorption kinetics, a large capacity (291 mg g−1), a high distribution coefficient, and, most importantly, a record‐high TcO4− uptake selectivity. This material can almost quantitatively remove TcO4− in the presence of a large excess of NO3− and SO42−. Decontamination experiments confirm that SCU‐102 represents the optimal Tc scavenger with the highest reported clean‐up efficiency, while first‐principle simulations reveal that the origin of the selectivity is the recognition of TcO4− by the hydrophobic pockets of the structure.
Reusable Nickel Nanoparticles‐Catalyzed Reductive Amination for Selective Synthesis of Primary Amines
Authors: Murugesan Kathiravan , Beller Matthias , Jagadeesh Rajenahally V. 
Published: February 2019

AbstractThe preparation of nickel nanoparticles as efficient reductive amination catalysts by pyrolysis of in situ generated Ni‐tartaric acid complex on silica is presented. The resulting stable and reusable Ni‐nanocatalyst enables the synthesis of functionalized and structurally diverse primary benzylic, heterocyclic and aliphatic amines starting from inexpensive and readily available carbonyl compounds and ammonia in presence of molecular hydrogen. Applying this Ni‐based amination protocol, ‐NH2moiety can be introduced in structurally complex compounds, for example, steroid derivatives and pharmaceuticals.
Chemical and Ribosomal Synthesis of Topologically Controlled Bicyclic and Tricyclic Peptide Scaffolds Primed by Selenoether Formation
Authors: Yin Yizhen , Fei Qianran , Liu Weidong , Li Zhuoru , Suga Hiroaki , Wu Chuanliu 
Published: February 2019

AbstractBicyclic and tricyclic peptides have emerged as promising candidates for the development of protein binders and new therapeutics. However, convenient and efficient strategies that can generate topologically controlled bicyclic and tricyclic peptide scaffolds from fully‐unprotected peptides are still much in demand, particularly for those amenable to the design of biosynthetic libraries. In this work, we report a reliable chemical and ribosomal synthesis of topologically controlled bicyclic and tricyclic peptide scaffolds. Our strategy involves the combination of selenoether cyclization followed by disulfide or thioether cyclization, yielding desirable bicyclic and tricyclic peptides. This work thus lays the foundation for developing peptide libraries with controlled topology of multicyclic scaffolds for in vitro display techniques.
Is a Bent Crystal Still a Single Crystal?
Authors: Commins Patrick , Karothu Durga Prasad , Naumov Panče 
Published: February 2019

AbstractThe mention of the word “crystal” invokes images of minerals, gems, and rocks, all of which are inevitably solid, hard, and durable entities with well‐defined smooth faces and straight edges. With the discovery in the first half of the 20th century that many molecular crystals are soft and can be deformed in a similar way as rubber or plastic, this perception is changing, and both the concept and formal definition of what a crystal is may require reinterpretation. The seemingly naïve question posed in the title of this Minireview does not have a simple answer. Here, we discuss how the effects of the elastic and plastic deformation of molecular crystals on the diffraction signature give primary evidence of their degree of crystallinity. In most cases, the definition of a crystal holds for both elastically and plastically deformed crystals and, unless there is significant or complete physical separation of the crystal during the deformation, they can safely be considered (deformed) single crystals with a high concentration of defects.
Controlled Reduction of Carboxamides to Alcohols or Amines by Zinc Hydrides
Authors: Ong Derek Yiren , Yen Zhihao , Yoshii Asami , Revillo Imbernon Julia , Takita Ryo , Chiba Shunsuke 
Published: February 2019

AbstractNew protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH‐ZnI2 system delivers alcohols and NaH‐ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc hydride (ZnH2)∞ is responsible for alcohol formation, whereas dimeric zinc chloride hydride (H−Zn−Cl)2 is the key species for the production of amines.
Fully Conjugated Two‐Dimensional sp2‐Carbon Covalent Organic Frameworks as Artificial Photosystem I with High Efficiency
Authors: Zhao Yingjie , Liu Hui , Wu Chenyu , Zhang Zhaohui , Pan Qingyan , Hu Fan , Wang Ruiming , Li Piwu , Huang Xiaowen , Li Zhibo 
Published: February 2019

AbstractThe synthesis of fully conjugated sp2‐carbon covalent organic frameworks (COF) is extremely challenging given the difficulty of the formation of very stable carbon‐carbon double bonds (‐C=C‐). Here, we report the successful preparation of a 2D COF (TP‐COF) based on triazine as central planar units bridged by sp2‐carbon linkers through the ‐C=C‐ condensation reaction. High‐resolution‐transmission electron microscopy (HRTEM) clearly confirmed the tessellated hexagonal pore structure with a pore center‐to‐center distance of 2 nm. Powder X‐ray diffraction (PXRD) together with structural simulations revealed an AA stacking mode of the obtained layered structure. TP‐COF turned out to be an excellent semiconductor material with a LUMO energy of −3.23 eV and a band gap of 2.36 eV. Excitingly, this novel sp2‐carbon conjugated TP‐COF exhibited unprecedented coenzyme regeneration efficiency and can significantly boost the coenzyme‐assisted synthesis ofl‐glutamate to a record‐breaking 97 % yield within 12 minutes.