bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lewis Säure‐katalysierte Transferhydromethallylierung für den Aufbau quartärer Kohlenstoffzentren
Authors: Walker Johannes C. L. , Oestreich Martin 
Published: August 2019

AbstractDas Design und die Synthese im Grammmaßstab eines cyclohexa‐1,4‐dienbasierten Surrogats für Isobutengas wird beschrieben. Unter Verwendung der stark elektronenarmen Lewis‐Säure B(C6F5)3 wurde die Hydromethallylierung elektronenreicher Styrolderivate zum Aufbau sterisch überfrachteter quartärer Kohlenstoffzentren erreicht. Die Reaktion verläuft unter C(sp3)‐C(sp3)‐Bindungsknüpfung an einem tertiären Carbeniumion, das selbst durch eine Alkenprotonierung erzeugt wird. Die Möglichkeit zweier gleichzeitig ablaufender Mechanismen wird auf der Grundlage mechanistischer Experimente mit einem deuterierten Surrogat vorgeschlagen.
Rapid Chemical Reaction Monitoring by Digital Microfluidics‐NMR: Proof of Principle Towards an Automated Synthetic Discovery Platform
Authors: Wu Bing , von der Ecken Sebastian , Swyer Ian , Li Chunliang , Jenne Amy , Vincent Franck , Schmidig Daniel , Kuehn Till , Beck Armin , Busse Falko , Stronks Henry , Soong Ronald , Wheeler Aaron R. , Simpson André 
Published: August 2019

AbstractMicrocoil nuclear magnetic resonance (NMR) has been interfaced with digital microfluidics (DMF) and is applied to monitor organic reactions in organic solvents as a proof of concept. DMF permits droplets to be moved and mixed inside the NMR spectrometer to initiate reactions while using sub‐microliter volumes of reagent, opening up the potential to follow the reactions of scarce or expensive reagents. By setting up the spectrometer shims on a reagent droplet, data acquisition can be started immediately upon droplet mixing and is only limited by the rate at which NMR data can be collected, allowing the monitoring of fast reactions. Here we report a cyclohexene carbonate hydrolysis in dimethylformamide and a Knoevenagel condensation in methanol/water. This is to our knowledge the first time rapid organic reactions in organic solvents have been monitored by high field DMF‐NMR. The study represents a key first step towards larger DMF‐NMR arrays that could in future serve as discovery platforms, where computer controlled DMF automates mixing/titration of chemical libraries and NMR is used to study the structures formed and kinetics in real time.
Visualization and In Situ Ablation of Intracellular Bacterial Pathogens through Metabolic Labeling
Authors: Hu Fang , Qi Guobin , Kenry  , Mao Duo , Zhou Shiwei , Wu Min , Wu Wenbo , Liu Bin 
Published: August 2019

AbstractProtected by the host cells, the hidden intracellular bacteria are typically difficult to kill by common antibiotics and cannot be visualized without complex cellular pretreatments. Herein, we successfully developed a bacteria‐metabolizable dual‐functional probe TPEPy‐d‐Ala, which is based on d‐alanine and a photosensitizer with aggregation‐induced emission for fluorescence turn‐on imaging of intracellular bacteria in living host cells and photodynamic ablation in situ. Once metabolically incorporated into bacterial peptidoglycan, the intramolecular motions of TPEPy‐d‐Ala are inhibited, leading to an enhanced fluorescent signal, which allows the clear visualization of the intracellular bacteria. Moreover, TPEPy‐d‐Ala can effectively ablate the labeled intracellular bacteria in situ owing to covalent ligation to peptidoglycan, yielding a low intracellular minimum inhibitory concentration (MIC) of 20±0.5 μg mL−1, much more efficient than that of a commonly used antibiotic, vancomycin.
Metastable Self‐Assembly of Theta‐Shaped Colloids and Twinning of Their Crystal Phases
Authors: Wang Linna , Lu Jiawei , Liu Bing 
Published: August 2019

AbstractAnisotropic colloids self‐assemble into different crystal structures compared to spherical colloids. Exploring and understanding their self‐assembly behavior could lead to creation of new materials with hierarchical structures through a bottom‐up process. Herein, we report metastable self‐assembly of theta‐shaped SiO2 colloids interacting with a depletion force in a quasi‐two‐dimensional space and we demonstrate that both a metastable “prone” crystal phase and a stable “standing” crystal phase can be formed, depending on the self‐assembly path. Path selection stems from an interplay between particle–particle interactions and particle–wall interactions. In particular, a twinning of the metastable crystals was observed and two twinning mirror axes were found. A variety of complex twinned crystals were formed by each individual mirror axis or their combinations.
Tetracrystalline Tetrablock Quarterpolymers: Four Different Crystallites under the Same Roof
Authors: Ladelta Viko , Zapsas George , Abou‐hamad Edy , Gnanou Yves , Hadjichristidis Nikos 
Published: August 2019

AbstractMulticrystalline block polymers having three or more crystalline segments are essential materials for the advancement of physics in the field of crystallinity. The challenging synthesis of multicrystalline polymers has resulted in only a limited number of tricrystalline terpolymers having been reported to date. We report, for the first time, the synthesis of polyethylene‐b‐poly(ethylene oxide)‐b‐poly(ϵ‐caprolactone)‐b‐poly(l‐lactide) (PE‐b‐PEO‐b‐PCL‐b‐PLLA), a tetracrystalline tetrablock quarterpolymer, by combining polyhomologation, ring‐opening polymerization, and an organic/metal “catalyst switch” strategy. 1H NMR spectroscopy and gel‐permeation chromatography confirmed the formation of the tetrablock quarterpolymer, while differential scanning calorimetry, X‐ray diffraction, and wide‐line separation solid‐state NMR spectroscopy revealed the existence of four different crystalline domains.
Elucidating the Mechanism of Working SnO2 Gas Sensors Using Combined Operando UV/Vis, Raman, and IR Spectroscopy
Authors: Elger Ann‐Kathrin , Hess Christian 
Published: August 2019

AbstractSnO2 is the most widely used metal oxide gas‐sensing material but a detailed understanding of its functioning is still lacking despite its relevance for applications. To gain new mechanistic insight into SnO2 gas sensors under working conditions, we have developed an operando approach based on combined UV/Vis, Raman, and FTIR spectroscopy, allowing us for the first time to relate the sensor response to the concentration of oxygen vacancies in the metal oxide, the nature of the adsorbates, and the gas‐phase composition. We demonstrate with the example of ethanol gas sensing that the sensor resistance is directly correlated with the number of surface oxygen vacancies and the presence of surface species, in particular, acetate and hydroxy groups. Our operando results enable an assessment of mechanistic models proposed in the literature to explain gas sensor operation. Owing to their fundamental nature, our findings are of direct relevance also for other metal oxide gas sensors.
Comprehensive Profiling of the Rheumatoid Arthritis Antibody Repertoire
Authors: Lo Ken C. , Sullivan Eric , Bannen Ryan M. , Jin Huiyan , Rowe Mark , Li Hanying , Pinapati Richard S. , Cartwright Adam J. , Tan John C. , Patel Jigar , Keystone Edward C. , Siminovitch Katherine A. 
Published: August 2019

ObjectiveAutoantibodies against citrullinated proteins are found in 64–89% of rheumatoid arthritis (RA) patients, with 88–99% specificity. This study was undertaken to create an unbiased, comprehensive profile of serum antibodies against the human proteome, including the citrullinome and the homocitrullinome, in RA patients, using a high‐density peptide array.MethodsOur high‐density peptide array, consisting of >4.6 million peptides, contained the entire annotated human proteome. The 20,246 proteins were represented as overlapping 16‐mer peptides. In addition to native peptides, citrullinated and homocitrullinated peptides were included, as substitutions for arginine and lysine, and provided a comprehensive screen against all possible epitopes. Twenty‐six serum samples (from 8 controls and 18 RA patients) were profiled on the high‐density peptide array. Using RA‐specific epitopes, we constructed an 8‐epitope diagnostic biomarker on a Gyrolab xPlore instrument with a cohort of 92 serum samples (from 29 controls and 63 RA patients). The diagnostic biomarker was further validated with an independent cohort of 181 serum samples (from 54 controls and 127 RA patients).ResultsIn the initial cohort the diagnostic performance of the 8‐epitope biomarker yielded 96.6% specificity and 92.1% sensitivity. The overall diagnostic performance in the validation cohort was 94.4% specificity and 85% sensitivity. In both cohorts, the performance of the 8‐epitope diagnostic biomarker compared favorably against the Abnova cyclic citrullinated peptide 2 (CCP2) assay. Using data from the peptide array, we identified novel RA‐specific epitopes and formed the basis of a new RA diagnostic assay.ConclusionComprehensive antibody profiling using a high‐density peptide array not only identified novel RA‐specific epitopes but also allowed us to construct a novel diagnostic biomarker that is as specific as and more sensitive than the Abnova CCP2 assay.
Single‐channel predefined‐time synchronisation of chaotic systems
Authors: Muñoz‐Vázquez Aldo Jonathan , Sánchez‐Torres Juan Diego , Anguiano‐Gijón Carlos Alberto 
Published: August 2019

AbstractChaos has attracted the interest of the research community due to its applications in secure communication, and in the study of complex systems in physics, engineering and other applied sciences. In the particular case of secure communication, fast synchronisation is a requirement to avoid any loss of information at the initial stage, when the signalisation data is transmitted. With the aim of providing fast and precise synchronisation, a novel algorithm is proposed in this paper, such that, by considering just one channel of communication, a dynamic observer synchronises with a chaotic system in predefined‐time. The proposal is based on the equivalent control concept of sliding mode theory, and the stability of the synchronisation is demonstrated in the Lyapunov framework. A simulation study is carried out to highlight the reliability of the proposed scheme.
“Partial Isometric” Solutions: A Special Ambiguity of the Optimal Configuration in MDS with Minkowski Metrics
Authors: Wolfrum Christine 
Published: August 2019

This article deals with a special kind of ambiguity of the optimal configuration calculated with the MDSCAL procedure. These configurations – the so‐called partial isometric solutions – are not restricted to the use of the MDSCAL procedure; they may always occur when using Minkowski metrics.For the City Block metric and the Supremum metric examples are demonstrated.
On Distributions of Wheat and Corn Yield
Authors: József S. 
Published: August 2019

For a more reliable planning of yields it is preferable to use various approaches using different methods and to make a combined use of the results. One of these approaches may be based upon the analysis of distributions of the yields.A study of the time series 1962‐1980 of the wheat and corn yields of all state farms showed that the normal distribution can be fitted to yearly data of yields well enough by the Sherman test.The changes over time of the distribution can be described by functions fitted for the parameters of the distribution with a group of selected economic and meteorological variables. This procedure may be used for estimation of the distribution of yields and we make such forecasts for the years joining to the reference period (1962‐1978).Tables and figures give some idea about the results.
A qualitative analysis of young people's experiences of receiving a novel, client‐led, psychological therapy in school
Authors: Churchman Anamaria , Mansell Warren , Al‐Nufoury Yasmin , Tai Sara 
Published: August 2019

AbstractMental health problems often arise in adolescence. Schools have been recognised as a potential hub for support; however, delivering targeted interventions in schools can be difficult due to impracticalities. Subsequently, students have little or no say in the support process. Given the importance of control in well‐being, the current study explored how adolescents experienced Method of Levels, a therapy that allowed them to choose if and when to attend therapy. Interviews with 14 adolescents were conducted and then analysed using thematic analysis. Three main themes were identified; therapy style, therapy experience and exploring problems. An additional overarching theme was generated, regarding choice and control. Findings indicate that adolescents value having choice and control. This made the therapy style accessible, enhanced the therapeutic experience and ultimately facilitated the process of exploring problems.
A Natural Diels‐Alder Biocatalyst Enables Efficient [4+2] Cycloaddition Under Harsh Reaction Conditions
Authors: Marsh Carl O. , Lees Nicholas R. , Han Li‐Chen , Byrne Matthew J. , Mbatha Sbusisiwe Z. , Maschio Laurence , Pagden‐Ratcliffe Sebastian , Duke Phillip W. , Stach James E. M. , Curnow Paul , Willis Christine L. , Race Paul R. 
Published: August 2019

AbstractCarbon‐carbon bond formation is a fundamental transformation in both synthetic chemistry and biosynthesis. Enzymes catalyze such reactions with exquisite selectivity which often cannot be achieved using non‐biological methods but may suffer from an intolerance of high temperature and the presence of organic solvents limiting their applications. Here we report the thermodynamic and kinetic stability of the β‐barrel natural Diels‐Alderase AbyU, which catalyzes formation of the spirotetronate core of the antimicrobial natural product abyssomicin C, with creation of 3 new asymmetric centers. This enzyme is shown to catalyze [4+2] cycloadditions at elevated temperature (up to 65 °C), and in the presence of organic solvents (MeOH, CH3CN and DMSO) and the chemical denaturant guanidinium hydrochloride, revealing that AbyU has potential widespread value as a biocatalyst.
An Intrinsic Photothermal Liquid for Light Detection and Energy Storage
Authors: Wang Zhen , Lian Xiaodong , Li Ruiting , Tao Xinglei , Wang Yapei 
Published: August 2019

AbstractPhotothermal materials (PTMs) have been intensively investigated in the fields of photothermal conversion. Superior to solid PTMs, liquid PTMs are leading the trends in satisfying the demands of high flexibility and easy recycling. Successful examples of liquid PTMs are mostly formulated by dispersing solid PTMs in solvents, but suffer from the problems of phase segregation and solvent pollution. In this work, a low‐cost formulation is proposed, which involves an oxidative product of ethyl oleate by iodine. It is an intrinsic liquid PTM, preserving the fluidic nature as well as possessing considerable ability for photothermal conversion. In addition to understanding the mechanism of light absorption in the visible and even near infrared windows, two examples are presented to demonstrate the great potential of liquid PTMs in broad areas such as light sensing and energy storage.
Controlled Growth of Ag Nanocrystals in a H‐Bonded Open Framework
Authors: Khodja Walid , Collière Vincent , Kahn Myrtil L. , Roques Nans , Sutter Jean‐Pascal 
Published: August 2019

AbstractA procedure that enabled rational access to the first example of hybrid material made of NPs grown within a H‐bonded framework is reported. To avoid competitive reactions with the framework units, the metal precursor was chemically trapped in the porous structure and subsequently photo‐reduced to afford the hybrid material Ag@SPA‐2, which consists of Ag NPs of nanometric sizes (<15 nm) homogeneously distributed in the crystals of the host material. In a subsequent step, taking advantage of the porous matrix the silver NPs have been transformed in situ to Ag2S NP by simple infiltration of H2S. The supramolecular network is shown to play an important role in stabilizing the inorganic nanomaterials and thus in controlling their growth.
Kinetic and Binding Studies Reveal Cooperativity and Off‐Cycle Competition for H‐Bonding Catalysis with Silsesquioxane Silanols
Authors: Jagannathan Jake R. , Diemoz Kayla M. , Targos Karina , Fettinger James C. , Franz Annaliese K. 
Published: August 2019

AbstractThe catalytic activity, kinetics, and quantification of H‐bonding ability of incompletely condensed polyhedral oligomeric silsesquioxane (POSS) silanols are reported. POSS‐triols, a homogeneous model for vicinal silica surface sites, exhibit enhanced H‐bonding compared with other silanols and alcohols as quantified using a 31P NMR probe. Evaluation of a Friedel–Crafts addition reaction shows that phenyl‐POSS‐triol is active as an H‐bond donor catalyst whereas other POSS silanols studied are not. An in‐depth kinetic study (using RPKA and VTNA) highlights the concentration‐dependent H‐bonding behavior of POSS‐triols, which is attributed to intermolecular association forming an off‐cycle dimeric species. Binding constants provide additional support for reduced H‐bond ability at higher concentrations, which is attributed to competitive association. POSS‐triol self‐association disrupts H‐bond donor abilities relevant for catalysis by reducing the concentration of active monomeric catalyst.
Stoichiometric Aldehyde Deformylation Mediated by Nucleophilic Peroxo‐diiron(III) Complex as a Functional Model of Aldehyde Deformylating Oxygenase
Authors: Kripli Balázs , Csendes Flóra Viktória , Török Patrik , Speier Gábor , Kaizer József 
Published: August 2019

AbstractThe reactivity of the previously reported peroxo adduct [FeIII2(μ‐O2)(MeBzim‐Py)4(CH3CN)2]4+ (1) (MeBzim‐Py=2‐(2′‐pyridyl)‐N‐methylbenzimidazole) towards aldehyde substrates including phenylacetaldehyde (PAA), hydrocinnamaldehyde (HCA), propionaldehyde (PA), 2‐phenylpropionaldehyde (PPA), cyclohexanecarboxaldehyde (CCA), and para‐substituted benzaldehydes (benzoyl chlorides) has been investigated. Complex 1 proved to be a nucleophilic oxidant in aldehyde deformylation reaction. These models, including detailed kinetic and mechanistic studies, may serve as the first biomimics of aldehyde deformylating oxygenase (ADO) enzymes.
A random‐effects model for clustered circular data
Authors: Rivest Louis‐Paul , Kato Shogo 
Published: August 2019

AbstractThis article considers a circular regression model for clustered data, where both the cluster effects and the regression errors have von Mises distributions. It involvesβ, a vector of parameters for the fixed effects, and two concentration parameters for the error distribution. A measure of intra‐cluster circular correlation and a predictor for an unobserved cluster random effect are studied. Preliminary estimators for the vectorβand the two concentration parameters are proposed, and their performance is compared with that of the maximum likelihood estimators in a simulation study. A numerical example investigating the factors impacting the orientation taken by a sand hopper when released is presented.The Canadian Journal of Statistics47: 712–728; 2019 © 2019 Statistical Society of Canada
On the Lewis Basicity of Phosphoramides: A Critical Examination of Their Donor Number through Comparison of Enthalpies of Adduct Formation with SbCl5and BF3
Authors: Gal Jean‐François , Maria Pierre‐Charles , Yáñez Manuel , Mó Otilia 
Published: August 2019

AbstractThe Lewis basicity of a series of phosphoryl compounds was examined using DFT and ab initio methods, including solvation effects. The enthalpies of adduct formation with two archetypal Lewis acids, antimony pentachloride and boron trifluoride, used to define the donor number DN and the BF3affinity (BF3A) respectively, were examined. The BF3adducts allow the use of the high‐accuracy G4 approach, whereas for SbCl5adducts, three different DFT formalisms, including empirical dispersion corrections, were used because the G4 formalism is not available for third‐row elements. For a comparison with experimental data, solvation effects were taken into account by using the polarizable continuum model. The experimental BF3affinities were well reproduced by G4 calculations when including PCM solvation. Conversely, comparisons of our calculated values and experimental results reported in the literature show that SbCl5enthalpies for phosphoramides are in error. In particular the DN for HMPA should be revised.
Electropolymerized o‐Phenylenediamine on Graphite Promoting the Electrochemical Detection of Nafcillin
Authors: Bottari Fabio , Moro Giulia , Sleegers Nick , Florea Anca , Cowen Todd , Piletsky Sergey , van Nuijs Alexander L. N. , De Wael Karolien 
Published: August 2019

AbstractBy combining molecular modelling and electrochemistry we envision the creation of modified electrodes tailored for a more sensitive and selective detection of a single analyte. In this study we report on a graphite screen printed electrode modified with electropolymerized o‐phenylenediamine, selected by rational design, which promotes the detection of nafcillin (NAF), an antibiotic. Parameters such as monomer concentration, pH and number of electropolymerization cycles were optimized to obtain the highest current signal for the target upon amperometric detection. NAF identification was based on the redox process at +1.1 V (vs pseudo Ag), ascribed to the oxidation of the C‐7 side chain. With the optimized modification protocol, a two‐fold increase in nafcillin signal could be obtained: the calibration plot in 0.1 M Britton‐Robinson buffer pH 4 showed a limit of detection of 80 nM with improved sensitivity and reproducibility (RSD<5 %) compared to the detection at non‐modified electrodes.
An Early–Life Stage Alternative Testing Strategy for Assessing the Impacts of Environmental Chemicals in Birds
Authors: Farhat Amani , Crump Doug , Bidinosti Lisa , Boulanger Emily , Basu Nil , Hecker Markus , Head Jessica A. 
Published: August 2019

Abstract
Early–life stage (ELS) toxicity tests are recognized as an advancement over current testing methodologies in terms of cost, animal use, and biological relevance. However, standardized ELS tests are not presently available for some vertebrate taxa, including birds. The present study describes a Japanese quail (Coturnix japonica) ELS test that is a promising candidate for standardization and applies it to test 8 environmental chemicals (ethinylestradiol, benzo[a]pyrene, chlorpyrifos, fluoxetine, lead(II)nitrate, trenbolone, seleno-L-methionine, hexabromocyclododecane). Individual chemicals were injected into the air cell of unincubated Japanese quail eggs at 3 concentrations, all predicted to cause ≤20% mortality. Survival to embryonic day 16 was consistently high (&gt;90%) among the vehicle-injected controls. All chemicals, except ethinylestradiol, were detected in liver tissue, most at concentrations suggestive of embryonic clearance. Adverse effects were observed for 5 of the 8 chemicals; chlorpyrifos (41.1 µg/g) significantly increased developmental abnormalities and decreased embryo and gallbladder mass. Ethinylestradiol (54.2 µg/g) and hexabromocyclododecane (0.02 µg/g) decreased embryo mass and tarsus length, respectively. Benzo[a]pyrene (0.83 µg/g) and fluoxetine hydrochloride (32.7 µg/g) exceeded the 20% mortality cutoff. No effects were observed following lead(II)nitrate, seleno-L-methionine, or trenbolone exposure up to 10.7, 0.07, and 4.4 µg/g, respectively. Overall, our ELS approach was time- and cost-effective, caused minimal mortality in controls, effectively delivered diverse chemicals to the embryo, and permitted identification of apical outcomes, all of which provide support toward standardization. Environ Toxicol Chem 2019;39:141–154. © 2019 SETAC