bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repairing Nanoparticle Surface Defects
Authors: Marino Emanuele , Kodger Thomas E. , Crisp Ryan W. , Timmerman Dolf , MacArthur Katherine E. , Heggen Marc , Schall Peter 
Published: September 2017

AbstractSolar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We utilized atomically thin semiconductor nanoplatelets as a convenient platform for studying, both microscopically and spectroscopically, the development of defects during ligand exchange with the conductive ligands Na4SnS4 and (NH4)4Sn2S6. These defects can be repaired via mild chemical or thermal routes, through the addition of L‐type ligands or wet annealing, respectively. This results in a higher‐quality, conductive, colloidally stable nanomaterial that may be used as the active film in optoelectronic devices.
Selective C−H Bond Cleavage in Methane by Small Gold Clusters
Authors: Lang Sandra M. , Bernhardt Thorsten M. , Chernyy Valeriy , Bakker Joost M. , Barnett Robert N. , Landman Uzi 
Published: September 2017

AbstractMethane represents the major constituent of natural gas. It is primarily used only as a source of energy by means of combustion, but could also serve as an abundant hydrocarbon feedstock for high quality chemicals. One of the major challenges in catalysis research nowadays is therefore the development of materials that selectively cleave one of the four C−H bonds of methane and thus make it amenable for further chemical conversion into valuable compounds. By employing infrared spectroscopy and first‐principles calculations it is uncovered herein that the interaction of methane with small gold cluster cations leads to selective C−H bond dissociation and the formation of hydrido methyl complexes, H‐Aux+‐CH3. The distinctive selectivity offered by these gold clusters originates from a fine interplay between the closed‐shell nature of the d states and relativistic effects in gold. Such fine balance in fundamental interactions could prove to be a tunable feature in the rational design of a catalyst.
Phosphate Transfer in Activated Protein Complexes Reveals Interaction Sites
Authors: Tamara Sem , Scheltema Richard A. , Heck Albert J. R. , Leney Aneika C. 
Published: September 2017

AbstractFor many proteins, phosphorylation regulates their interaction with other biomolecules. Herein, we describe an unexpected phenomenon whereby phosphate groups are transferred non‐enzymatically from one interaction partner to the other within a binding interface upon activation in the gas phase. Providing that a high affinity exists between the donor and acceptor sites, this phosphate transfer is very efficient and the phosphate groups only ligate to sites in proximity to the binding region. Consequently, such phosphate‐transfer reactions may define with high precision the binding site between a phosphoprotein and its binding partner, as well as reveal that the binding site in this system is retained in the phase transfer from solution to the gas phase.
Columnar Lithium Metal Anodes
Authors: Zhang Xue‐Qiang , Chen Xiang , Xu Rui , Cheng Xin‐Bing , Peng Hong‐Jie , Zhang Rui , Huang Jia‐Qi , Zhang Qiang 
Published: September 2017

AbstractThe rechargeable lithium metal anode is of utmost importance for high‐energy‐density batteries. Regulating the deposition/dissolution characteristics of Li metal is critical in both fundamental researches and practical applications. In contrast to gray Li deposits featured with dendritic and mossy morphologies, columnar and uniform Li is herein plated on lithium‐fluoride (LiF)‐protected copper (Cu) current collectors. The electrochemical properties strongly depended on the microscale morphologies of deposited Li, which were further embodied as macroscale colors. The as‐obtained ultrathin and columnar Li anodes contributed to stable cycling in working batteries with a dendrite‐free feature. This work deepens the fundamental understanding of the role of LiF in the nucleation/growth of Li and provides emerging approaches to stabilize rechargeable Li metal anodes.
Spin Changes Accompany Ultrafast Structural Interconversion in the Ground State of a Cobalt Nitrosyl Complex
Authors: Marroux Hugo J. B. , Curchod Basile F. E. , Faradji Charly A. , Shuttleworth Timothy A. , Sparkes Hazel A. , Pringle Paul G. , Orr‐Ewing Andrew J. 
Published: September 2017

AbstractUltrafast, reversible intersystem crossing (ISC) is reported under ambient conditions for the electronic ground state of the pentacoordinate cobalt nitrosyl complexes, [CoX2(NO)(PMePh2)2] (X=Cl, Br), in solution. ISCs on such short timescales are more typically observed in electronically excited states reached by absorption of ultraviolet or visible light. Singlet and triplet electron spin states of the complex, corresponding to two different isomers, are populated at room temperature, and the two isomers exchange on a timescale of a few picoseconds. Ultrafast two‐dimensional infrared spectroscopy observes the change in wavenumber of the NO ligand band accompanying the isomerization and associated ISC on the (spin) adiabatic ground potential energy surface. Comparison of the dynamics of the chloro‐ and bromo‐complexes shows that inertial effects of the ligand motion have a greater effect than spin–orbit coupling on determining the forward and reverse isomerization and ISC rates.
Organocatalytic Intramolecular [4+2] Cycloaddition between In Situ Generated Vinylidene ortho‐Quinone Methides and Benzofurans
Authors: Wu Xiaoyan , Xue Lu , Li Dongmei , Jia Shiqi , Ao Jun , Deng Jun , Yan Hailong 
Published: September 2017

AbstractDescribed herein is the enantioselective construction of oxygen‐containing [5‐6‐5] tricyclic heterocycles by an organocatalyzed asymmetric [4+2] cycloaddition of vinylidene ortho‐quinone methides and benzofurans. According to this methodology, a series of oxygen‐containing [5‐6‐5] tricyclic heterocycles with various functional groups were synthesized in excellent enantio‐ and diastereoselectivities (>99 % ee, >20:1 d.r.). Furthermore, the deuterium‐labeling experiments and high‐resolution mass spectroscopy demonstrated that a vinylidene ortho‐quinone methide intermediate was involved and possibly resulted from a prototropic rearrangement of 2‐ethynylphenol. Remarkably, a catalyst loading as low as 0.1 mol %, and a gram‐scale synthesis were achieved for this transformation.
Reductive Coupling of Acrylates with Ketones and Ketimines by a Nickel‐Catalyzed Transfer‐Hydrogenative Strategy
Authors: Buxton Craig S. , Blakemore David C. , Bower John F. 
Published: September 2017

AbstractNickel‐catalyzed coupling of benzyl acrylates with activated ketones and imines provides γ‐butyrolactones and lactams, respectively. The benzyl alcohol byproduct released during the lactonization/lactamization event is relayed to the next cycle where it serves as the reductant for C−C bond formation. This strategy represents a conceptually unique approach to transfer‐hydrogenative C−C bond formation, thus providing examples of reductive heterocyclizations where hydrogen embedded within an alcohol leaving group facilitates turnover.
Hydrosulfonylation Reaction with Arenesulfonyl Chlorides and Tetrahydrofuran: Conversion of Terminal Alkynes into Cyclopentylmethyl Sulfones
Authors: Gloor Christian Simon , Dénès Fabrice , Renaud Philippe 
Published: September 2017

AbstractAn efficient and simple radical chain reaction to convert terminal alkynes into arenesulfonylmethylcyclopentanes is described. The reaction involves a radical addition–translocation–cyclization process and necessitates solely the use of readily available arenesulfonyl chlorides in tetrahydrofuran. Interestingly, this radical‐mediated C−H activation process took place with a high level of retention of configuration when an enantiomerically pure starting material was used.
Constructing arabinofuranosidases for dual arabinoxylan debranching activity
Authors: Wang Weijun , Andric Nikola , Sarch Cody , Silva Bruno T. , Tenkanen Maija , Master Emma R. 
Published: September 2017

AbstractEnzymatic conversion of arabinoxylan requires α‐L‐arabinofuranosidases able to remove α‐L‐arabinofuranosyl residues (α‐L‐Araf) from both mono‐ and double‐substituted D‐xylopyranosyl residues (Xylp) in xylan (i.e., AXH‐m and AXH‐d activity). Herein, SthAbf62A (a family GH62 α‐L‐arabinofuranosidase with AXH‐m activity) and BadAbf43A (a family GH43 α‐L‐arabinofuranosidase with AXH‐d3 activity), were fused to create SthAbf62A_BadAbf43A and BadAbf43A_SthAbf62A. Both fusion enzymes displayed dual AXH‐m,d and synergistic activity toward native, highly branched wheat arabinoxylan (WAX). When using a customized arabinoxylan substrate comprising mainly α‐(1 → 3)‐L‐Arafand α‐(1 → 2)‐L‐Arafsubstituents attached to disubstituted Xylp(d‐2,3‐WAX), the specific activity of the fusion enzymes was twice that of enzymes added as separate proteins. Moreover, the SthAbf62A_BadAbf43A fusion removed 83% of all α‐L‐Araffrom WAX after a 20 hr treatment.1H NMR analyses further revealed differences in SthAbf62A_BadAbf43 rate of removal of specific α‐L‐Araf substituents from WAX, where 9.4 times higher activity was observed toward d‐α‐(1 → 3)‐L‐Arafcompared to m‐α‐(1 → 3)‐L‐Arafpositions.
Metabonomic analysis of serum reveals antifatigue effects of Yi Guan Jian on fatigue mice using gas chromatography coupled to mass spectrometry
Authors: Shui Sufang , Cai Xiaorong , Huang Rongqing , Xiao Bingkun , Yang Jianyun 
Published: September 2017

AbstractYi Guan Jian (YGJ), one of the most commonly used traditional Chinese medicines, has been reported to possess significant antifatigue effects. However, the mechanisms underlying its antifatigue effects remain largely unresolved. In this study, a metabonomics approach, involving gas chromatography coupled to mass spectrometry and a multivariate statistical technique, was developed to estimate the extent to which YGJ alleviated the exhausting swimming‐induced fatigue of mice. High‐dose treatment with YGJ significantly extended the swimming time of fatigued mice. Significant alterations of metabolites involving amino acids, organic acids and carbohydrates were observed in the serum of fatigued mice, which were reversed by YGJ treatment while biochemical indexes returned to normal. These metabolic changes suggest that the antifatigue effect of YGJ is associated with the impairement of amino acid, organic acids and carbohydrates. It also appears that YGJ can induce significant metabolic alterations independent of the exhausting swimming‐induced metabolic changes. The significantly altered metabolites induced by YGJ intervention include l‐2‐amino‐acetoacetate, taurine, fumaric acid, malic acid, oxoadipic acid and l‐aspartate, all of which are associated with antifatigue properties. This suggests that YGJ exerts chemopreventive effects via antifatigue mechanisms.
Exploring the mechanism of Jieduquyuziyin prescription on systemic lupus erythematosus by GC–MS‐based urine metabolomics
Authors: Wei Jing , Gao Jun , Ding Xinghong 
Published: September 2017

AbstractA urine metabolomics method based on gas chromatography–mass spectrometry was developed in order to investigate the metabolite characteristics of systemic lupus erythematosus (SLE) and the therapeutic effects of Jieduquyuziyin prescription. The urinary metabolic profiles in urine specimens of the SLE model mice (MRL/lpr) group, prednisone acetate‐treated SLE mouse group, Jieduquyuziyin prescription‐treated SLE mouse group, and control group (C57BL/6 J) after the administration were analyzed by gas chromatography–mass spectrometry. These metabolic profiles were then processed by multivariate analysis, in particular Mass Profiler Professional, SIMCA‐P and partial least‐squares discriminant analysis. According to the partial least‐squares discriminant analysis results, the SLE model group and the control group were obviously separated, indicating that the incidence of SLE had a greater impact on the metabolic network, and the SLE model group had significant difference compared with the control group in urine metabolites. Eleven differential metabolites were identified to be related to SLE, and the results of differential metabolite identification showed that the metabolites were mainly related to energy metabolism and amino acid metabolism pathway. These results can provide an experimental basis for further exploring the mechanism of traditional Chinese medicine in the treatment of SLE.
Chromatographic approaches for the characterization and quality control of therapeutic oligonucleotide impurities
Authors: El Zahar N. M. , Magdy N. , El‐Kosasy A. M. , Bartlett Michael G. 
Published: September 2017

AbstractPhosphorothioate (PS) oligonucleotides are a rapidly rising class of drugs with significant therapeutic applications. However, owing to their complex structure and multistep synthesis and purification processes, generation of low‐level impurities and degradation products are common. Therefore, they require significant investment in quality control and impurity identification. This requires the development of advanced methods for analysis, characterization and quantitation. In addition, the presence of the PS linkage leads to the formation of chiral centers which can affect their biological properties and therapeutic efficiency. In this review, the different types of oligonucleotide impurities and degradation products, with an emphasis on their origin, mechanism of formation and methods to reduce, prevent or even eliminate their production, will be extensively discussed. This review will focus mainly on the application of chromatographic techniques to determine these impurities but will also discuss other approaches such as mass spectrometry, capillary electrophoresis and nuclear magnetic resonance spectroscopy. Finally, the chirality and formation of diastereomer mixtures of PS oligonucleotides will be covered as well as approaches used for their characterization and the application for the development of stereochemically‐controlled PS oligonucleotides.
An educational software to reinforce the comprehensive learning of materials selection
Authors: Rodríguez‐Prieto Alvaro , Camacho Ana M. , Merayo David , Sebastián Miguel A. 
Published: September 2017

AbstractAn educational software, called CalSev 1.0.2, has been developed for supporting the teaching in materials selection seminars. As a case study, a selection of materials for nuclear reactor pressure vessels has been chosen, because it is a representative example of the relationship between chemical composition, mechanical properties, and in‐service behavior. This software has been developed to improve the students’ understanding of the materials selection tasks, providing an interactive user‐friendly platform that allows to modify—in real time—the content of chemical elements and mechanical requirements to obtain a materials performance evaluation. Due to its versatility, this informatics tool represents a great value for educational purposes, with special impact in blended and distance learning, by simplifying the arduous task of materials selection for a wide range of applications and promoting a collaborative working environment by easing the creation of small groups analyzing different study cases. Finally, to evaluate the functionality, interest, user‐friendliness and the educational characteristics of CalSev 1.0.2, a survey among 36 undergraduate students has been carried out.
Correctness assessment of a crowdcoding project in a computer programming introductory course
Authors: Ferrán Sebastián , Beghelli Alejandra , Huerta‐Cánepa Gonzalo , Jensen Federico 
Published: September 2017

AbstractCrowdcoding is a programming model that outsources a software project implementation to the crowd. As educators, we think that crowdcoding could be leveraged as part of the learning path of engineering students from a computer programming introductory course to solve local community problems. The benefits are twofold: on the one hand the students practice the concepts learned in class and, on the other hand, they participate in real‐life problems. Nevertheless, several challenges arise when developing a crowdcoding platform, the first one being how to check the correctness of student's code without giving an extra burden to the professors in the course. To overcome this issue, we propose a novel system that does not resort to expert review; neither requires knowing the right answers beforehand. The proposed scheme automatically clusters the student's codes based solely on the output they produce. Our initial results show that the largest cluster contains the same codes selected as correct by the automated and human testing, as long as some conditions apply.
IMECE—Implementation of mathematical, experimental, and computer‐based education: A special application of fluid mechanics for civil and environmental engineering students
Authors: Yetilmezsoy Kaan 
Published: September 2017

AbstractA novel educational methodology, Implementation of Mathematical, Experimental, and Computer‐based Education (IMECE), where its name was derived from the letters of the word “imece” (a Turkish tradition) by taking into account the integrative meaning of this cultural concept, was proposed to explore the synergistic effect of the conventional mathematical solution procedure, visual application, and MATLAB‐based simulation on the perceptions and learning quality of the engineering students. Within the scope the present research carried out both at the state university (undergraduate and graduate levels) and at the foundation university (undergraduate level), water discharge problem (a special case of the Bernoulli's principle/Toricelli's law) was chosen as an example application. In the study, the experimental results of three different tank models (vertical cylindrical, conical, and spherical) and the solution algorithms written in MATLAB were presented in detail, and new empirical equations were also developed for each laboratory scale system depending on the experimental data. The effectiveness of the proposed IMECE method was evaluated statistically within the framework of both “Student Survey” and “Student Assessment” conducted with the participation of 84 students. Based on the mean scores obtained for all participating students, the results of the statistical tests indicated that the quantitative performance (or effectiveness) of the applied IMECE methodology was determined as 97.73%, 67.36%, and 82.55% for the perception/satisfaction section, the learning section, and the overall evaluation category, respectively.
‘This is Not Just About History…’ Addressing the Disconnect in Historic (Non‐Recent) Child Abuse Investigations
Authors: Aldridge Jo 
Published: September 2017

Key Practitioner Messages:

Historic (non‐recent) child abuse investigations need to consider the effects of investigative processes on victims and survivors.
Such investigations include those undertaken by the police and by the Independent Inquiry into Child Sexual Abuse (IICSA).
Victim and survivor accounts need to be taken seriously and investigated thoroughly in order for victims/survivors not to feel let down by, and disconnected from, criminal justice and IICSA processes.
‘Historic (non‐recent) child abuse investigations need to consider the effects of investigative processes on victims and survivors’
Substrate Recognition by a Dual‐Function P450 Monooxygenase GfsF Involved in FD‐891 Biosynthesis
Authors: Miyanaga Akimasa , Takayanagi Ryuichi , Furuya Takashi , Kawamata Ayano , Itagaki Tomohiro , Iwabuchi Yoshiharu , Kanoh Naoki , Kudo Fumitaka , Eguchi Tadashi 
Published: September 2017

AbstractGfsF is a multifunctional P450 monooxygenase that catalyzes epoxidation and subsequent hydroxylation in the biosynthesis of macrolide polyketide FD‐891. Here, we describe the biochemical and structural analysis of GfsF. To obtain the structural basis of a dual‐function reaction, we determined the crystal structure of ligand‐free GfsF, which revealed GfsF to have a predominantly hydrophobic substrate binding pocket. The docking models, in conjunction with the results of the enzymatic assay with substrate analogues and site‐directed mutagenesis suggested two distinct substrate binding modes for epoxidation and hydroxylation reactions, which explained how GfsF regulates the order of two oxidative reactions. These findings provide new insights into the reaction mechanism of multifunctional P450 monooxygenases.
Identification of Chimeric αβγ Diterpene Synthases Possessing both Type II Terpene Cyclase and Prenyltransferase Activities
Authors: Mitsuhashi Takaaki , Okada Masahiro , Abe Ikuro 
Published: September 2017

AbstractTwo unusual diterpene synthases composed of three domains (α, β, and γ) were identified from fungal Penicillium species. They are the first enzymes found to possess both type II terpene cyclase (TC) and prenyltransferase (PT) activities. These enzymes were characterized by heterologous expression in Aspergillus oryzae and in vitro experiments with wild‐type, mutated, and truncated enzymes. The results revealed that the α domain in the C‐terminal region of these enzymes was responsible for the PT activity, whereas the βγ domains in the N‐terminal region composed the type II TC, and formed copalyl diphosphate (2). Additionally, between the α and βγ domains, there is a characteristic linker region, in which minimal secondary structure is predicted. This linker does not exist in the characterized three‐domain (αβγ) terpene synthases known as monofunctional type I or type II TCs, or bifunctional type I and type II TC enzymes. Therefore, both the catalytic activities and protein architecture substantially differentiate these new enzymes from the previously characterized terpene synthases.
Five‐year follow‐up of the endothelial progenitor cell capturing stent versus the paxlitaxel‐eluting stent in de novo coronary lesions with a high risk of coronary restenosis
Authors: Woudstra Pier , Kalkman Deborah N. , Beijk Marcel A. , Klomp Margo , Damman Peter , Koch Karel T. , Henriques Jose P. S. , Baan Jan , Vis Marije M. , Piek Jan J. , Tijssen Jan G. P. , de Winter Robbert J. 
Published: September 2017

AbstractObjectivesTo assess the long‐term safety and clinical efficacy of the Genous endothelial progenitor cell capturing stent (ECS) compared with the TAXUS Liberté paclitaxel‐eluting stent (PES) in lesions with a high risk of restenosis.BackgroundInstead of the use of cytotoxic or cytostatic drugs in drug‐eluting stents, a “pro‐healing” approach in ECS may overcome impeded healing response due to delayed functional endothelialization of the stent struts.MethodsIn the prospective, randomized TRIAS pilot study 193 patients with coronary artery lesions carrying a high risk of restenosis were included (ECS: n = 98, PES: n = 95). The primary focus of this analysis was target vessel failure (TVF) at 5 years. Dual antiplatelet therapy was prescribed for ≥1 month after ECS and for ≥6 months after PES.ResultsAt 5 years follow‐up, no significant differences were found in TVF (ECS 24% vs. PES 29%, risk difference 95% confidence interval (RDCI) −17.3% to 7.4%). Between 2 and 5 years after the index procedure, low numbers of TVF were observed in ECS compared with PES (ECS 4% vs. PES 16%, RDCI −20.8% to −2.3%). There was no definite stent thrombosis in ECS compared with four patients in the PES group.ConclusionThis is the first randomized study providing very long‐term clinical efficacy and safety of the ECS in lesions carrying a high risk of restenosis. At 5 years follow‐up, TVF rates in ECS group are numerically lower compared with PES due to an increase of events between 2 and 5 years after the index procedure.