bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diboryldiborene: π‐konjugierte B4‐Ketten isoelektronisch zum Butadien‐Dikation
Authors: Hermann Alexander , Cid Jessica , Mattock James D. , Dewhurst Rian D. , Krummenacher Ivo , Vargas Alfredo , Ingleson Michael J. , Braunschweig Holger 
Published: June 2018

AbstractDie Umsetzung von Bis(catecholato)diboran mit N‐heterocyclischen Carbenen (NHCs) lieferte sp2‐sp3‐Diborane, die hochselektiv einen Catechol/Bromid‐Austausch am sp3‐Boratom eingehen. Die Reduktion der erhaltenen 1,1‐Dibromdiboran‐Addukte führte zur reduktiven Kupplung und Isolierung von zweifach NHC‐stabilisierten 1,2‐Diboryldiborenen. Mit diesen Molekülen konnte erstmals eine Delokalisierung von π‐Elektronen über eine nur aus Boratomen bestehende Kette realisiert werden.
Green and Rapid Hydrothermal Crystallization and Synthesis of Fully Conjugated Aromatic Compounds
Authors: Taublaender M. Josef , Glöcklhofer Florian , Marchetti‐Deschmann Martina , Unterlass Miriam M. 
Published: June 2018

AbstractHighly fused, fully conjugated aromatic compounds are interesting candidates for organic electronics. With higher crystallinity their electronic properties improve. It is shown here that the crystallization of three archetypes of such molecules—pentacenetetrone, indigo, and perinone—can be achieved hydrothermally. Given their molecular structure, this is a truly startling finding. In addition, it is demonstrated that perinone can also be synthesized in solely high‐temperature water from the starting compounds naphthalene bisanhydride and o‐phenylene diamine without the need for co‐solvents or catalysts. The transformation can be drastically accelerated by the application of microwave irradiation. This is the first report on the hydrothermal generation of two fused heterocycles.
Ca12[Mn19N23] and Ca133[Mn216N260]: Structural Complexity by 2D Intergrowth
Authors: Ovchinnikov Alexander , Bobnar Matej , Prots Yurii , Borrmann Horst , Sichelschmidt Jörg , Grin Yuri , Höhn Peter 
Published: June 2018

AbstractTwo new calcium nitridomanganates, Ca12[Mn19N23] (P3, a=11.81341(3) Å, c=5.58975(2) Å, Z=1) and Ca133[Mn216N260] (
, a=39.477(1) Å, c=5.5974(2) Å, Z=1), were obtained by a gas–solid reaction of Ca3N2 and Mn with N2 at 1273 K and 1223 K, respectively. The crystal structure of Ca12[Mn19N23] was determined from high‐resolution X‐ray synchrotron powder diffraction data, whereas single‐crystal X‐ray diffraction was employed to establish the crystal structure of the Ca133[Mn216N260] phase, which classifies as a complex metallic alloy (CMA). Both crystal structures have 2D nitridomanganate layers containing similar building blocks but of different levels of structural complexity. Bonding analysis as well as magnetic susceptibility and electron spin resonance measurements revealed that only a fraction of the Mn atoms in both structures carries a localized magnetic moment, while for most Mn species the magnetism is quenched as a result of metal–metal bond formation.
Efficient and Robust Hydrogen Evolution: Phosphorus Nitride Imide Nanotubes as Supports for Anchoring Single Ruthenium Sites
Authors: Yang Jian , Chen Bingxu , Liu Xiaokang , Liu Wei , Li Zhijun , Dong Juncai , Chen Wenxing , Yan Wensheng , Yao Tao , Duan Xuezhi , Wu Yuen , Li Yadong 
Published: June 2018

AbstractAmorphous phosphorus nitride imide nanotubes (HPN) are reported as a novel substrate to stabilize materials containing single‐metal sites. Abundant dangling unsaturated P vacancies play a role in stabilization. Ruthenium single atoms (SAs) are successfully anchored by strong coordination interactions between the d orbitals of Ru and the lone pair electrons of N located in the HPN matrix. The atomic dispersion of Ru atoms can be distinguished by X‐ray absorption fine structure measurements and spherical aberration correction electron microscopy. Importantly, Ru SAs@PN is an excellent electrocatalyst for the hydrogen evolution reaction (HER) in 0.5 m H2SO4, delivering a low overpotential of 24 mV at 10 mA cm−2 and a Tafel slope of 38 mV dec−1. The catalyst exhibits robust stability in a constant current test at a large current density of 162 mA cm−2 for more than 24 hours, and is operative for 5000 cycles in a cyclic voltammetry test. Additionally, Ru SAs@PN presents a turnover frequency (TOF) of 1.67 H2 s−1 at 25 mV, and 4.29 H2 s−1 at 50 mV, in 0.5 m H2SO4 solution, outperforming most of the reported hydrogen evolution catalysts. Density functional theory (DFT) calculations further demonstrate that the Gibbs free energy of adsorbed H* over the Ru SAs on PN is much closer to zero compared with the Ru/C and Ru SAs supported on carbon and C3N4, thus considerably facilitating the overall HER performance.
Diboryldiborenes: π‐Conjugated B4 Chains Isoelectronic to the Butadiene Dication
Authors: Hermann Alexander , Cid Jessica , Mattock James D. , Dewhurst Rian D. , Krummenacher Ivo , Vargas Alfredo , Ingleson Michael J. , Braunschweig Holger 
Published: June 2018

AbstractB(sp2)–B(sp3) diborane species based on bis(catecholato)diboron and N‐heterocyclic carbenes (NHCs) underwent catechol/bromide exchange selectively at the sp3‐hybridized boron atom. The reduction of the resulting 1,1‐dibromodiborane adducts led to reductive coupling and isolation of doubly NHC‐stabilized 1,2‐diboryldiborenes. These compounds are the first examples of molecules exhibiting π‐electron delocalization over an all‐boron chain.
Transition‐Metal‐Catalyzed Three‐Component Difunctionalizations of Alkenes
Authors: Zhang Ji‐Shu , Liu Long , Chen Tieqiao , Han Li‐Biao 
Published: June 2018

AbstractThree‐component reactions can directly convert three reactants into the desired products in one pot and thus greatly shorten the synthetic path. Recently, transition‐metal catalysis has been applied in the difunctionalization of alkenes and remarkable progress has been achieved to facilitate the construction of a wide range of functional molecules with high atom‐ and step‐economic efficiency. This Focus Review highlights recent advances in this field.
Down‐regulating Proteolysis to Enhance Anticancer Activity of Peptide Nanofibers
Authors: Li Jie , Du Xuewen , Powell Devon J. , Zhou Rong , Shi Junfeng , He Hongjian , Feng Zhaoqianqi , Xu Bing 
Published: June 2018

AbstractNanofibers of short peptides are emerging as a promising type of agents for inhibiting cancer cells. But the proteolysis of peptides decreases the anticancer efficacy of the peptide nanofibers. Here we show that decreasing the activity of proteasomes enhance the activity of peptide nanofibers for inhibiting cancer cells. Based on the structure of galactin‐3, we designed a heptapeptide, which self‐assembles to form nanofibers. The nanofibers of the heptapeptide exhibit moderate cytotoxicity to three representative cancer cell lines (HeLa, MCF‐7, and HepG2), largely due to the proteolysis of the peptides. Using a clinically approved proteasome inhibitor, bortezomib, to treat the cancer cells significantly decreases the proteolysis of the peptides and enhances the activity of the peptide nanofibers for inhibiting the cancer cells. This work illustrates a promising approach for enhancing the anticancer efficacy of peptide nanofibers by modulating intracellular protein degradation machinery, as well as provides insights for understanding the cytotoxicity of aberrant protein or peptide aggregates in complicated cellular environment.
Generalized Nonlinear Stiffness Identification on Controlled Mechanical Vibrating Systems
Authors: Beltran‐Carbajal Francisco , Silva‐Navarro Gerardo 
Published: June 2018

AbstractA new algebraic parametric identification method in time domain for multiple degrees‐of‐freedom mechanical vibrating systems with high‐order nonlinear stiffness is proposed. Parameters of mass, damping and linear and nonlinear stiffness are estimated on‐line and, simultaneously, using transient real‐time position measurements and active control force signals. Parametric identification can be applied for real‐time estimation of both symmetrical and non‐symmetrical stiffness. Parametric identification is combined with adaptive planned motion control on Multiple‐Input‐Multiple‐Output nonlinear mechanical vibrating systems. Analytical and numerical results prove the effectiveness and efficiency of the proposed on‐line algebraic parametric identification approach.
Transformation of Nonlinear MIMO Discrete‐Time Systems into the Extended Observer Form
Authors: Kaparin Vadim , Kotta Ülle 
Published: June 2018

AbstractThe paper addresses the problem of transforming discrete‐time multi‐input multi‐output nonlinear state equations into the extended observer form, which, besides the inputs and outputs, also depends on a finite number of their past values. Necessary and sufficient conditions for the existence of the extended coordinate transformation are formulated in terms of differential one‐forms, associated with the input‐output equations, corresponding to the state equations. The difference between the single‐input single‐output and multi‐input multi‐output cases is described. The applicability of the conditions is illustrated by an example.
Extreme malleability of preferences: Absolute preference sign changes under uncertainty
Authors: Vosgerau Joachim , Peer Eyal 
Published: June 2018

AbstractMalleability of preferences is a central tenet of behavioral decision theory. How malleable preferences really are, however, is a topic of debate. Do preference reversals imply preference construction? We argue that to claim preferences are construed, a demonstration of more extreme preference malleability than simple preference reversals is required: absolute preference sign changes within participants. If respondents value a prospect positively in 1 condition but negatively in a different condition, preferences cannot be considered stable. Such absolute preference sign changes are possible under uncertainty. In 2 incentive‐compatible experiments, we found participants were willing to pay to take part in a gamble and also demanded to be compensated to take part in a subsequent gamble with identical outcomes and probabilities. Such absolute preference sign changes within participants led to simultaneous risk aversion and risk seeking for the same risky prospect, suggesting that, at least in the domain of risky decisions, consumers' preferences are indeed malleable and construed.
Enhancing efficiency, reliability, and rigor in competency model analysis using natural language processing
Authors: Garman Andrew N. , Standish Melanie P. , Kim Dae Hyun 
Published: June 2018

BackgroundCompetency modeling is frequently used in higher education and workplace settings to inform a variety of learning and performance improvement programs. However, approaches commonly taken to modeling tasks can be very labor‐intensive, and are vulnerable to perceptual and experience biases of raters.AimsThe present study assesses the potential for natural language processing (NLP) to support competency‐related tasks, by developing a baseline comparison of results generated by NLP to results generated by human raters.MethodsTwo raters separately conducted cross‐walks for leadership competency models of graduate healthcare management programs from eight universities against a newly validated competency model from the National Center for Healthcare Leadership containing 28 competencies, to create 224 cross‐walked pairs of “best matches”.ResultsResults indicated that the NLP model performed at least as accurately as human raters, who required a total of 16 work hours to complete, versus the NLP calculations which were nearly instantaneous.ConclusionBased on these findings, we conclude that NLP has substantial promise as a high‐efficiency adjunct to human evaluations in competency cross‐walks.
Behavior of Alkaline‐Metal Catalysts in Supercritical Water Gasification of Lignite
Authors: Qu Xuan , Zhou Xianxian , Yan Xiaoqiang , Zhang Rong , Bi Jicheng 
Published: June 2018

AbstractThe efficient utilization of abundant low‐rank coals, which show high moisture and ash content, is significant for coal‐based energy systems. The gasification of Zhaotong lignite was performed with different alkaline‐metal catalysts, such as KOH, NaOH, K2CO3, and Na2CO3, in supercritical water. The behavior of the alkaline metal was also investigated. Potassium shows better catalytic activity than sodium. KOH not only promotes breakage of chemical bonds in the coal matrix to generate low‐molecular‐weight gases, but also alters the pore structure of the char to improve the gasification of carbon in the residue. However, potassium is partly inactivated upon reaction with minerals in coal in supercritical water gasification. In situ protection of potassium is realized by adding Ca(OH)2 under supercritical conditions.
Binding Studies of Metal–Salphen and Metal–Bipyridine Complexes towards G‐Quadruplex DNA
Authors: Łęczkowska Anna , Gonzalez‐Garcia Jorge , Perez‐Arnaiz Cristina , Garcia Begoña , White Andrew J. P. , Vilar Ramon 
Published: June 2018

AbstractThe proposed in vivo formation of G‐quadruplex DNA (G4 DNA) in promoter regions of oncogenes and in telomeres has prompted the development of small molecules with high affinity and selectivity for these structures. Herein we report the synthesis of a new di‐substituted bipyridine ligand and the corresponding complexes with Ni2+ and VO2+. Both these new complexes have been characterized spectroscopically and by X‐ray crystallography. Detailed DNA binding studies of these two complexes, together with three previously reported metal salphen complexes, are presented. Using FRET melting assays, the binding affinity and selectivity of the five metal complexes against six different G4 DNA structures as well as a duplex DNA have been determined. In addition, we present detailed ITC and UV/Vis studies to characterize the interaction of the complexes with human telomeric G4 DNA. Finally, we show via a polymerase stop assay that these complexes are able to stabilize a G4 DNA structure (from the c‐Myc oncogene promoter) and halt the activity of Taq polymerase.
Concomitant Site‐Specific Incorporation of Silver(I) and Mercury(II) Ions into a DNA Duplex
Authors: Jash Biswarup , Müller Jens 
Published: June 2018

AbstractA GNA (glycol nucleic acid)‐based nucleoside analogue containing 1 H‐imidazo[4,5‐f][1,10]phenanthroline (P) as an artificial nucleobase was used to form a stable mercury(II)‐mediated P‐HgII‐T‐H base pair within a parallel‐stranded DNA duplex. The nucleobase P shows an affinity towards silver(I) and mercury(II), tuneable through the acidity of the medium when the canonical nucleobase thymine is located in its complementary position. This extraordinary behavior was exploited to enable the concomitant site‐specific incorporation of silver(I) and mercury(II) into a DNA scaffold for the first time. This achievement is all the more remarkable because it was made possible by the involvement of only one type of artificial nucleobase. The simultaneous incorporation of two different soft metal ions with a precise control of their respective positions within the nucleic acid scaffold significantly reduces the complexity in the formation of a heterometallic array of metal ions in DNA and thereby facilitates new applications of metal‐functionalized nucleic acids.
Molybdenum Imido, Tungsten Imido and Tungsten Oxo Alkylidene N‐Heterocyclic Carbene Olefin Metathesis Catalysts
Authors: Buchmeiser Michael R. 
Published: June 2018

AbstractThis article outlines the fundamental concept to molybdenum imido, tungsten imido and tungsten oxo alkylidene N‐heterocyclic carbene (NHC) catalysts for olefin metathesis. Starting from Mo(NR)(CHCMe2R′)(OTf)2⋅DME (R=alkyl, aryl; R′=CH3, Ph; OTf=CF3SO3; DME=1,2‐dimethoxyethane), W(NR)(CHCMe2Ph)X2 (X=pyrrolide, OR′′, SiPh3) and W(O)Cl2(CHCMe2Ph)(PMe2Ph)2, respectively, the neutral, pentacoordinated 16‐valence electron (VE) complexes became accessible. These serve as precursors for the corresponding cationic, tetracoordinated 14‐VE catalysts. This class of olefin metathesis catalysts based on group 6 metal alkylidene NHCs is characterized by a broad structural variability, high activity, high productivity and, in tailored systems, high functional group tolerance even vs. protic groups including alcohols and carboxylic acids. Also, high regio‐ and stereoselectivity is achieved, both in ring‐opening metathesis polymerization (ROMP) and in the cyclopolymerization of α,ω‐diynes. Fundamentals concerning the influence of the imido/oxo ligand, the different NHCs and the anionic ligands on catalyst performance and stability as well as reaction pathways are summarized. Also, the concepts for catalyst immobilization, whether via the NHC or by substitution of an alkoxide, are presented. Finally, special features such as the use of betaine‐type anionic ligands (alkoxides and sulfonates), which offer access to ionic catalysts for use biphasic reaction setups, are briefly outlined.
Structural Designs for Accommodating Volume Expansion in Sodium Ion Batteries
Authors: Wang Wenjie , Zhu Xiaohui , Zhang Yujing , Liu Yongjun , Zhang Qin , Fu Lei 
Published: June 2018

AbstractAt the forefront of energy storage field, developing sodium ion batteries (SIBs) has drew a wide concern due to relatively low cost and abundant resource, comparing with lithium ion batteries (LIBs). Serious volume expansion constraints the electrochemical performance of the conversion/alloying materials, despite of their high reversible capacities or theoretical capacities. Here, from the perspective of structural designs, we systematically study four types of routes to accommodate volume expansion. Delicate and peculiar nanostructures based on nanocrystallization engineering are widely focused on, covering nanosheet assembly and nanoarray construction. Robust materials such as carbon‐based materials can be utilized as the buffer matrix, mitigating the mechanical stress during the charge/discharge process. Besides, recent studies have demonstrated void space reservation in nanostructures was also beneficial for adapting to volume changes. Moreover, for conversion materials, numerous works have confirmed the advantageous influence of interlayer spacing regulation. We also explained the superiority and challenges for further giving scope to structural designs. Sketching out the future studies in SIBs, in situ characterizations are supposed to be highlighted, as well as in‐depth researches on the stress evolution caused by volume expansion.
Aspirin® – so schnell wie nie?!
Authors: Rodriguez Maren , Salzner Jens , Lühken Arnim 
Published: June 2018

AbstractDer Beitrag stellt eine alltags‐ und problemorientierte Lerngelegenheit vor. Das Werbeversprechen „Aspirin® – so schnell wie nie, dank MicroAktiv‐Technologie“ wird durch Einsatz eines schultauglichen Modells einer pharmazeutischen „Basket‐Apparatur“ und der Photometrie mit Hilfe des Smartphones schulexperimentell überprüft und sachgerecht bewertet.
Assessing and fostering students’ scientific literacy in doing comparative investigation tasks
Authors: Hild Pitt , Metzger Susanne , Parchmann Ilka 
Published: June 2018

AbstractDieser Artikel liefert konkrete Beispiele zur Beurteilung und Förderung experimenteller Kompetenzen im Bereich Erkenntnisgewinnung. Es werden zunächst Grundlagen für die Entwicklung kompetenzorientierter hands‐on Experimentieraufgaben am Beispiel des „effektbasierten Vergleichens“ beschrieben. Bei diesen Aufgaben müssen Schülerinnen und Schüler unterschiedliche Objekte anhand einer gegebenen Eigenschaft experimentell vergleichen. Unterschiedliche zu erreichende Kompetenzen aus dem Bereich der Erkenntnisgewinnung wurden a priori, anhand eines Strukturmodells, postuliert. Mithilfe validierter Testaufgaben und eines standardisierten Manuals konnte bei einer Stichprobe von 418 12‐ bis 15‐jährigen Schülerinnen und Schülern (jeweils 2 Aufgaben mit gleichem Aufgabenstamm pro Person) eine Progression entlang dieser Kompetenzen nachgewiesen werden. Die Übereinstimmungen zwischen den Prüferinnen und Prüfern liegen alle in einem akzeptablen bis sehr guten Bereich. Die Ergebnisse sollen die Grundlage für die Konstruktion von Lernumgebungen liefern, die es den Lehrpersonen erlauben, Kompetenzen im Bereich der Erkenntnisgewinnung zu beurteilen und individuell zu fördern.
Use of the progression of adapted Diabetes Complications Severity Index to predict acute coronary syndrome, ischemic stroke, and mortality in Asian patients with type 2 diabetes mellitus: A nationwide cohort investigation
Authors: Hu Wei‐Syun , Lin Cheng‐Li 
Published: June 2018

BackgroundWe report on a retrospective population study aimed at identifying and validating the progression of adapted Diabetes Complications Severity Index (DCSI) for acute coronary syndrome (ACS), ischemic stroke, and mortality in Asian people with type 2 diabetes mellitus (DM).MethodsUtilizing a Taiwanese national dataset, we included 84 450 type 2 diabetic individuals between 2000 and 2011. The area under the receiver operating characteristic curve (C statistics of logistic model) and the C statistics of the Cox model were used to evaluate whether the progression of diabetic complication status could be a predictor of ACS, ischemic stroke, and death. The optimum threshold for adverse outcomes risk stratification were obtained using Youden's J statistic as the cutoff that gives the highest threshold.ResultsAmong the study patients, the C statistics of the logistic model of the progression of the score predictive of ACS, ischemic stroke, and death were 0.72 (95% confidence interval [CI]: 0.71–0.73), 0.84 (95% CI: 0.84–0.85), and 0.66 (95% CI: 0.65–0.67), respectively. The progression of adapted DCSI had moderate discrimination for ACS, ischemic stroke, and death (C statistics = 0.71, 0.72, and 0.75, respectively) based on Cox regression analysis (Harrell C). The optimum threshold of the progression of the score for ACS, ischemic stroke, and death in type 2 DM patients were 0.30, 0.36, and 0.39, respectively.ConclusionsThe acceptable discriminative power of the progression of adapted DCSI for Asian people affected by type 2 DM was demonstrated in a large cohort in Taiwan.