bluuebunny/crossref_metadata_2025_split huggingface dataset:
Topological Phase Transition of Non‐Hermitian Crosslinked Chain
Authors: Zhao X. L. , Chen L. B. , Fu L. B. , Yi X. X. 
Published: April 2020

AbstractThe contents of topological classification of matter are enriched by non‐Hermiticity, such as exceptional points, bulk‐edge correspondence, and skin effects. Physically, gain and loss can be introduced by imaginary on‐site potentials of lattice Hamiltonians, and the topological phase transition for a cross‐linked chain in the presence of such non‐Hermiticity is investigated. The topological phase diagram in terms of a winding number is obtained analytically with phase boundaries coinciding with the surfaces of exceptional points. The topologically original edge states with distribution mainly at the joints between domains of different phases are protected even
for long chains. The non‐Hermitian topological feature can also be reflected by vortex structures in the vector fields of complex eigenenergies, expected values of Pauli matrices, and trajectories of these quantities. This model may be implemented in coupled photonic crystals, fermions trapped in optical lattice, or non‐Hermitian electrical‐circuit lattices, and the edge states are immune to various kinds of disorders until topological phase transition occurs. This work gives insight into the influence of non‐Hermiticity on topological phase of matter.
Transition‐Metal‐Free Carbon Isotope Exchange of Phenyl Acetic Acids
Authors: Destro Gianluca , Horkka Kaisa , Loreau Olivier , Buisson David‐Alexandre , Kingston Lee , Del Vecchio Antonio , Schou Magnus , Elmore Charles S. , Taran Frédéric , Cantat Thibault , Audisio Davide 
Published: April 2020

AbstractA transition‐metal‐free carbon isotope exchange procedure on phenyl acetic acids is described. Utilizing the universal precursor CO2, this protocol allows the carbon isotope to be inserted into the carboxylic acid position, with no need of precursor synthesis. This procedure enabled the labeling of 15 pharmaceuticals and was compatible with carbon isotopes [14C] and [13C]. A proof of concept with [11C] was also obtained with low molar activity valuable for distribution studies.
Molecular Expansion for Constructing Porous Organic Polymers with High Surface Areas and Well‐Defined Nanopores
Authors: Liu Yuchuan , Wang Shun , Meng Xianyu , Ye Yu , Song Xiaowei , Liang Zhiqiang , Zhao Yanli 
Published: April 2020

AbstractConstruction of porous organic polymers (POPs) with high surface areas, well‐defined nanopores, and excellent stability remains extremely challenging because of the unmanageable reaction process. Until now, only a few reported POPs have Brunauer‐Emmett‐Teller (BET) surface areas (SBET) exceeding 3000 m2 g−1. Herein, we demonstrate a molecular expansion strategy to integrate high surface areas, large nanopore sizes, and outstanding stability into POPs. A series of hyper‐crosslinked conjugated polymers (HCCPs) with exceptional porosity are synthesized through this strategy. Specially, HCCP‐6 and HCCP‐11 exhibit the highest surface areas (SBET >3000 m2 g−1) and excellent total pore volumes (up to 3.98 cm3 g−1) among these HCCPs. They present decent total CH4 storage capacities of 491 and 421 mg g−1 at 80 bar and 298 K, respectively. Meanwhile, they are highly stable in harsh environments. The facile and general molecular expansion strategy would lead to improved synthetic routes of POPs for desired functions.
Aufbau‐ und Abbaureaktionen von weißem Phosphor induziert durch N‐heterocyclische Carbenkomplexe von Nickel(0)
Authors: Hierlmeier Gabriele , Coburger Peter , van Leest Nicolaas P. , de Bruin Bas , Wolf Robert 
Published: April 2020

AbstractDie Reaktion von Nickel(0)‐Verbindungen mit weißem Phosphor (P4) ist eine kaum erforschte Syntheseroute für binäre Nickelphosphidcluster. Wir zeigen, dass die Reaktion von P4 mit koordinativ und elektronisch ungesättigten N‐heterocyclischen Carbenkomplexen von Nickel(0) die Darstellung ungewöhnlicher Clusterverbindungen mit P1‐, P3‐, P5‐ und P8‐Einheiten ermöglicht. Die Verwendung von [Ni(IMes)2] [IMes=1,3‐Bis(2,4,6‐trimethylphenyl)imidazolin‐2‐yliden] führt zu Spezies mit Ni3P4‐ und Ni3P6 Gerüst, die als superhypercloso‐ bzw. hypercloso‐Cluster beschrieben werden können. Komplexe mit sterisch anspruchsvolleren Carbenliganden [Ni(IPr)2] bzw. [(IPr)Ni(η6‐Toluol) [IPr=1,3‐Bis(2,6‐diisopropylphenyl)imidazolin‐2‐yliden] führen hingegen zur Synthese eines closo‐Ni3P8‐Clusters. Die inversen Sandwichkomplexe [(NHC)2Ni2P5] (NHC=IMes, IPr) mit einem aromatischen cyclo‐P5−‐Liganden wurden als weitere Reaktionsprodukte identifiziert.
Synthesis of All‐Carbon Disubstituted Bicyclo[1.1.1]pentanes by Iron‐Catalyzed Kumada Cross‐Coupling
Authors: Nugent Jeremy , Shire Bethany R. , Caputo Dimitri F. J. , Pickford Helena D. , Nightingale Frank , Houlsby Ian T. T. , Mousseau James J. , Anderson Edward A. 
Published: April 2020

Abstract1,3‐Disubstituted bicyclo[1.1.1]pentanes (BCPs) are important motifs in drug design as surrogates for p‐substituted arenes and alkynes. Access to all‐carbon disubstituted BCPs via cross‐coupling has to date been limited to use of the BCP as the organometallic component, which restricts scope due to the harsh conditions typically required for the synthesis of metallated BCPs. Here we report a general method to access 1,3‐C‐disubstituted BCPs from 1‐iodo‐bicyclo[1.1.1]pentanes (iodo‐BCPs) by direct iron‐catalyzed cross‐coupling with aryl and heteroaryl Grignard reagents. This chemistry represents the first general use of iodo‐BCPs as electrophiles in cross‐coupling, and the first Kumada coupling of tertiary iodides. Benefiting from short reaction times, mild conditions, and broad scope of the coupling partners, it enables the synthesis of a wide range of 1,3‐C‐disubstituted BCPs including various drug analogues.
Experimental Determination of Magnetic Anisotropy in Exchange‐Bias Dysprosium Metallocene Single‐Molecule Magnets
Authors: Meng Yin‐Shan , Xiong Jin , Yang Mu‐Wen , Qiao Yu‐Sen , Zhong Zhi‐Qiang , Sun Hao‐Ling , Han Jun‐Bo , Liu Tao , Wang Bing‐Wu , Gao Song 
Published: April 2020

AbstractWe investigate a family of dinuclear dysprosium metallocene single‐molecule magnets (SMMs) bridged by methyl and halogen groups [Cp′2Dy(μ‐X)]2 (Cp′=cyclopentadienyltrimethylsilane anion; 1: X=CH3−; 2: X=Cl−; 3: X=Br−; 4: X=I−). For the first time, the magnetic easy axes of dysprosium metallocene SMMs are experimentally determined, confirming that the orientation of them are perpendicular to the equatorial plane which is made up of dysprosium and bridging atoms. The orientation of the magnetic easy axis for 1 deviates from the normal direction (by 10.3°) due to the stronger equatorial interactions between DyIII and methyl groups. Moreover, its magnetic axes show a temperature‐dependent shifting, which is caused by the competition between exchange interactions and Zeeman interactions. Studies of fluorescence and specific heat as well as ab initio calculations reveal the significant influences of the bridging ligands on their low‐lying exchange‐based energy levels and, consequently, low‐temperature magnetic properties.
Formation of Hierarchical FeCoS2–CoS2 Double‐Shelled Nanotubes with Enhanced Performance for Photocatalytic Reduction of CO2
Authors: Wang Yan , Wang Sibo , Zhang Song Lin , Lou Xiong Wen (David) 
Published: April 2020

AbstractHierarchical FeCoS2–CoS2 double‐shelled nanotubes have been rationally designed and constructed for efficient photocatalytic CO2 reduction under visible light. The synthetic strategy, engaging the two‐step cation‐exchange reactions, precisely integrates two metal sulfides into a double‐shelled tubular heterostructure with both of the shells assembled from ultrathin two‐dimensional (2D) nanosheets. Benefiting from the distinctive structure and composition, the FeCoS2–CoS2 hybrid can reduce bulk‐to‐surface diffusion length of photoexcited charge carriers to facilitate their separation. Furthermore, this hybrid structure can expose abundant active sites for enhancing CO2 adsorption and surface‐dependent redox reactions, and harvest incident solar irradiation more efficiently by light scattering in the complex interior. As a result, these hierarchical FeCoS2–CoS2 double‐shelled nanotubes exhibit superior activity and high stability for photosensitized deoxygenative CO2 reduction, affording a high CO‐generating rate of 28.1 μmol h−1 (per 0.5 mg of catalyst).
Fast Hydrocarbon Oxidation by a High‐Valent Nickel–Fluoride Complex
Authors: Mondal Prasenjit , Lovisari Marta , Twamley Brendan , McDonald Aidan R. 
Published: April 2020

AbstractIn the search for highly reactive oxidants we have identified high‐valent metal–fluorides as a potential potent oxidant. The high‐valent Ni–F complex [NiIII(F)(L)] (2, L=N,N′‐(2,6‐dimethylphenyl)‐2,6‐pyridinedicarboxamidate) was prepared from [NiII(F)(L)]− (1) by oxidation with selectfluor. Complexes 1 and 2 were characterized by using 1H/19F NMR, UV‐vis, and EPR spectroscopies, mass spectrometry, and X‐ray crystallography. Complex 2 was found to be a highly reactive oxidant in the oxidation of hydrocarbons. Kinetic data and products analysis demonstrate a hydrogen atom transfer mechanism of oxidation. The rate constant determined for the oxidation of 9,10‐dihydroanthracene (k2=29 m−1 s−1) compared favorably with the most reactive high‐valent metallo‐oxidants. Complex 2 displayed reaction rates 2000–4500‐fold enhanced with respect to [NiIII(Cl)(L)] and also displayed high kinetic isotope effect values. Oxidative hydrocarbon and phosphine fluorination was achieved. Our results provide an interesting direction in designing catalysts for hydrocarbon oxidation and fluorination
Enhanced Multiple Anchoring and Catalytic Conversion of Polysulfides by Amorphous MoS3 Nanoboxes for High‐Performance Li‐S Batteries
Authors: Yu Jian , Xiao Jiewen , Li Anran , Yang Zhao , Zeng Liang , Zhang Qianfan , Zhu Yujie , Guo Lin 
Published: April 2020

AbstractThe practical implementation of lithium–sulfur batteries is obstructed by poor conductivity, sluggish redox kinetics, the shuttle effect, large volume variation, and low areal loading of sulfur electrodes. Now, amorphous N‐doped carbon/MoS3 (NC/MoS3) nanoboxes with hollow porous architectures have been meticulously designed as an advanced sulfur host. Benefiting from the enhanced conductivity by the N‐doped carbon, reduced shuttle effect by the strong chemical interaction between unsaturated Mo and lithium polysulfides, improved redox reaction kinetics by the catalytic effect of MoS3, great tolerance of volume variation and high sulfur loading arising from flexible amorphous materials with hollow‐porous structures, the amorphous NC/MoS3 nanoboxes enabled sulfur electrodes to deliver a high areal capacity with superior rate capacity and decent cycling stability. The synthetic strategy can be generalized to fabricate other amorphous metal sulfide nanoboxes.
Rhodiumkatalysierte elektrooxidative C‐H‐Olefinierung von Benzamiden
Authors: Zhang Yan , Struwe Julia , Ackermann Lutz 
Published: April 2020

AbstractMetallkatalysierte, Chelat‐unterstützte C‐H‐Olefinierungen haben sich zu einem leistungsstarken Werkzeug für die Herstellung von funktionalisierten Alkenen entwickelt. Nun beschreiben wir die rhodaelektrokatalysierte C‐H‐Aktivierung/Alkenylierung von Arenen. Die Olefinierung von herausfordernden, elektronenarmen Benzamiden verläuft unter elektrochemischen Bedingungen ausschließlich nach einem dehydrierenden Mechanismus und vermeidet den Einsatz eines chemischen Oxidationsmittels in stöchiometrischer Menge, sodass H2 als einziges Koppelprodukt gebildet wird. Die vielfältige Alkenylierungsreaktion mit elektrischen Strom als “grünem” Oxidationsmittel weist ein breites Anwendungsspektrum auf.
Enantioselective Synthesis of 3‐Fluorochromanes via Iodine(I)/Iodine(III) Catalysis
Authors: Sarie Jérôme C. , Thiehoff Christian , Neufeld Jessica , Daniliuc Constantin G. , Gilmour Ryan 
Published: April 2020

AbstractThe chromane nucleus is common to a plenum of bioactive small molecules where it is frequently oxidized at position 3. Motivated by the importance of this position in conferring efficacy, and the prominence of bioisosterism in drug discovery, an iodine(I)/iodine(III) catalysis strategy to access enantioenriched 3‐fluorochromanes is disclosed (up to 7:93 e.r.). In situ generation of ArIF2 enables the direct fluorocyclization of allyl phenyl ethers to generate novel scaffolds that manifest the stereoelectronic gauche effect. Mechanistic interrogation using deuterated probes confirms a stereospecific process consistent with a type IIinv pathway.
Rhodium‐Catalyzed Electrooxidative C−H Olefination of Benzamides
Authors: Zhang Yan , Struwe Julia , Ackermann Lutz 
Published: April 2020

AbstractMetal‐catalyzed chelation‐assisted C−H olefinations have emerged as powerful tools for the construction of functionalized alkenes. Herein, we describe the rhoda‐electrocatalyzed C−H activation/alkenylation of arenes. The olefinations of challenging electron‐poor benzamides were thus accomplished in a fully dehydrogenative fashion under electrochemical conditions, avoiding stoichiometric chemical oxidants, and with H2 as the only byproduct. This versatile alkenylation reaction also features broad substrate scope and used electricity as a green oxidant.
Forward‐backward doubly stochastic differential equations with random jumps and related games
Authors: Zhu Qingfeng , Shi Yufeng , Teng Bin 
Published: April 2020

AbstractA type of forward‐backward doubly stochastic differential equations driven by Brownian motions and the Poisson process (FBDSDEP) is studied. Under some monotonicity assumptions, the existence and uniqueness results for measurable solutions of FBDSDEP are established via a method of continuation. Then the continuity and differentiability of the solutions to FBDSDEP depending on parameters is discussed. Furthermore, these results were applied to backward doubly stochastic linear quadratic (LQ) nonzero sum differential games with random jumps to get the explicit form of the open‐loop Nash equilibrium point by the solution of the FBDSDEP.
Ganzglaskonstruktion für das Dach des Pützerturms der TU Darmstadt
Authors: Schula Sebastian , Schneider Jens 
Published: April 2020

AbstractVor über 75 Jahren wurde die Pützerturmhaube des Uhrturms der Technischen Universität Darmstadt in der Brandnacht vom 11. September 1944 zerstört. Seitdem präsentiert sich der ehemalige Uhrturm als Stumpf am zentralen Standort der Universität. Dem Entwurf von Walter & Sichau Architekten folgend erhielt der Turm nun einen neuen Turmabschluss in moderner Formsprache. Die als absturzsichernde Ganzglaskonstruktion ausgeführte Konstruktion greift die Anpassungen an die baulichen Veränderungen der Nachkriegszeit auf und fügt sich so in das Gebäudeensemble ein. Die aus lediglich vier großformatigen und etwa jeweils 2 t schweren Glaselementen bestehende Konstruktion folgt dem Trend immer größerer Ganzglasanwendungen. Im vorliegenden Beitrag werden die Konstruktionseigenschaften beschrieben und an diesem Beispiel die objektspezifischen Abweichungen zu den technischen Baubestimmungen und die hiermit wesentlich verbundenen erforderlichen Nachweise aufgezeigt, welche schlussendlich eine vorhabenbezogene Bauartgenehmigung (vBG) ermöglichten.
Effects of Inferred Gender on Patterns of Co‐Authorship in Ecology and Evolutionary Biology Publications
Authors: Frances Dachin N. , Fitzpatrick Connor R. , Koprivnikar Janet , McCauley Shannon J. 
Published: April 2020

AbstractSenior positions in academia such as tenured faculty and editorial positions often exhibit large gender imbalances across a broad range of research disciplines. The forces driving these imbalances have been the subject of extensive speculation and a more modest body of research. Given the central role publications play in determining individual outcomes and progress in academic settings, unequal patterns of authorship across gender could be a potent driver of observed gender imbalance in academia. Here, we investigate patterns of co‐authorship across four journals in ecology and evolutionary biology at four time‐points spanning four decades. Co‐authorship patterns are of interest because collaborations are important in scientific research, affecting individual researcher productivity, and increasingly, funding opportunities. Based on inferred gender from set criteria, we found significant differences between male and female researchers in their tendency to publish with female co‐authors. Specifically, compared to women, male researchers in the last author position were more likely to co‐author papers with other males. While we did find that the proportion of female co‐authors has increased modestly over the last thirty years, this is strongly correlated with an increase in the average number of authors per paper over time. Additionally, the proportion of female co‐authors on papers remains well below the proportion of PhDs awarded to females in biology.
The Vertebrate Tooth Row: Is It Initiated by a Single Organizing Tooth?
Authors: Sadier Alexa , Jackman William R. , Laudet Vincent , Gibert Yann 
Published: April 2020

AbstractTeeth are one of the most fascinating innovations of vertebrates. Their diversity of shape, size, location, and number in vertebrates is astonishing. If the molecular mechanisms underlying the morphogenesis of individual teeth are now relatively well understood, thanks to the detailed experimental work that has been performed in model organisms (mainly mouse and zebrafish), the mechanisms that control the organization of the dentition are still a mystery. Mammals display simplified dentitions when compared to other vertebrates with only a single tooth row positioned in the anterior part of the mouth, whereas other vertebrates exhibit tooth rows in many locations. As proposed 60 years ago, tooth rows can be formed sequentially from an initiator tooth. Recent results in zebrafish have now largely confirmed this hypothesis. Here this observation is generalized upon and it is suggested that in most vertebrates tooth rows could form sequentially from a single initiator tooth.
The area between ROC curves, a non‐parametric method to evaluate a biomarker for patient treatment selection
Authors: Blangero Yoann , Rabilloud Muriel , Laurent‐Puig Pierre , Le Malicot Karine , Lepage Côme , Ecochard René , Taieb Julien , Subtil Fabien 
Published: April 2020

AbstractTreatment selection markers are generally sought for when the benefit of an innovative treatment in comparison with a reference treatment is considered, and this benefit is suspected to vary according to the characteristics of the patients. Classically, such quantitative markers are detected through testing a marker‐by‐treatment interaction in a parametric regression model. Most alternative methods rely on modeling the risk of event occurrence in each treatment arm or the benefit of the innovative treatment over the marker values, but with assumptions that may be difficult to verify. Herein, a simple non‐parametric approach is proposed to detect and assess the general capacity of a quantitative marker for treatment selection when no overall difference in efficacy could be demonstrated between two treatments in a clinical trial. This graphical method relies on the area between treatment‐arm‐specific receiver operating characteristic curves (ABC), which reflects the treatment selection capacity of the marker. A simulation study assessed the inference properties of the ABC estimator and compared them with other parametric and non‐parametric indicators. The simulations showed that the estimate of the ABC had low bias, power comparable to parametric indicators, and that its confidence interval had a good coverage probability (better than the other non‐parametric indicator in some cases). Thus, the ABC is a good alternative to parametric indicators. The ABC method was applied to data of the PETACC‐8 trial that investigated FOLFOX4 versus FOLFOX4 + cetuximab in stage III colon adenocarcinoma. It enabled the detection of a treatment selection marker: theDDR2 gene.
A doubly auxotrophic CHO‐K1 cell line for the production of recombinant monoclonal antibodies
Authors: Zhang Qinghao , Jiang Bo , Du Zhimei , Chasin Lawrence A. 
Published: April 2020

AbstractChinese hamster ovary (CHO) cells are the most widely used mammalian hosts for recombinant protein production due to their hardiness, ease of transfection, and production of glycan structures similar to those in natural human monoclonal antibodies. To enhance the usefulness of CHO‐K1 cells we developed a new selection system based on double auxotrophy. We used CRISPR‐Cas9 to knockout the genes that encode the bifunctional enzymes catalyzing the last two steps in the de novo synthesis of pyrimidines and purines (uridine monophosphate synthase and 5‐aminoimidazole‐4‐carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase [ATIC], respectively). Survival of these doubly auxotrophic cells depends on the provision of sources of purines and pyrimidines or on the transfection and integration of open reading frames encoding these two enzymes. We successfully used one such double auxotroph (UA10) to select for stable transfectants carrying (a) the recombinant tumor necrosis factor‐α receptor fusion protein etanercept and (b) the heavy and light chains of the anti‐Her2 monoclonal antibody trastuzumab. Transfectant clones produced these recombinant proteins in a stable manner and in substantial amounts. The availability of this double auxotroph provides a rapid and efficient selection method for the serial or simultaneous transfer of genes for multiple polypeptides of choice into CHO cells using readily available purine‐ and pyrimidine‐free commercial media.
Tangential flow filtration of haptoglobin
Authors: Pires Ivan S. , Palmer Andre F. 
Published: April 2020

AbstractHaptoglobin (Hp) is a plasma glycoprotein that scavenges cell‐free hemoglobin (Hb). Hp has various potential therapeutic applications, but it has been mainly studied for treatment of acute hemolytic conditions that can arise from situations such as massive blood transfusion, infusion of stored red blood cells, severe burns, trauma, sepsis, radiation injury, and others. Therefore, Hp may also be beneficial during chronic hemolytic disease states such as hereditary spherocytosis, nocturnal hemoglobinuria, sickle‐cell anemia, and malaria. Various methods have been developed to purify Hp from plasma or plasma fractions. However, none of these methods have exploited the large molecular weight (MW) range distribution of Hp polymers to easily isolate Hp from other plasma proteins. The present study used tangential flow filtration (TFF) to isolate polymeric Hp from plasma proteins using human Fraction IV (FIV) as the starting material. After removal of insoluble material from a suspension of FIV paste, the protein mixture was clarified on a 0.2 μm hollow fiber (HF) TFF filter. The clarified protein solution was then bracketed based on protein MW using HF filters with MW cut‐offs (MWCOs) of 750, 500, and 100 kDa. Using untreated FIV, the Hp purity of the main bracket was ~75% with a total Hb binding capacity (HbBC) yield of 1.2 g starting from 500 g of FIV paste. However, pretreatment of FIV with fumed silica to remove lipoproteins increased Hp purity to >95% with a HbBC yield of 1.7 g per 500 g of FIV. Taken together this study provides a novel and scalable method to purify Hp from plasma or plasma fractions.