bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrating historical biogeography and environmental niche evolution to understand the geographic distribution of Datureae
Authors: Dupin Julia , Smith Stacey D. 
Published: May 2019

PremiseThe distributions of plant clades are shaped by abiotic and biotic factors as well as historical aspects such as center of origin. Dispersals between distant areas may lead to niche evolution when lineages are established in new environments. Alternatively, dispersing lineages may exhibit niche conservatism, moving between areas with similar environmental conditions. Here we test these contrasting hypotheses in the Datureae clade (Solanaceae).MethodsWe used maximum likelihood methods to estimate the ancestral range of Datureae along with the history of biogeographic events. We then characterized the niche of each taxon using climatic and soil variables and tested for shifts in environmental niche optima. Finally, we examined how these shifts relate to the niche breadth of taxa and clades within Datureae and the degree of overlap between them.ResultsDatureae originated in the Andes and subsequently expanded its range to North America and non‐Andean regions of South America. The ancestral niche, and that of mostDaturaandTrompettiaspecies, is dry, whileBrugmansiaspecies likely shifted toward a more mesic environment. Nonetheless, most Datureae present moderate to high overlap in niche breadth today.ConclusionsThe expansion of Datureae into North America was associated with niche conservatism, with dispersal into similarly dry areas as occupied by the ancestral lineage. Subsequent niche evolution, including the apparent shift to a mesic niche inBrugmansia, diversified the range of habitats occupied by species in the tribe Datureae but also led to significant niche overlap among the three genera.
Rhodium‐Catalyzed [5+1]‐Cycloaddition Reactions to Spiro‐Benzo[e][1,3]Oxazineindoline Imines
Authors: Han Cuifen , Wu Wenjin , Chen Zhiyuan , Pu Shouzhi 
Published: May 2019

AbstractA Rh‐catalyzed [5+1] cycloaddition reaction for the synthesis of spirocyclicindoline imine from 3‐diazoindolin‐2‐imine with benzo[d]isoxazole is reported. The reaction proceeds under gentle catalytic conditions, thus giving the expected spiro[benzo[e][1,3]oxazine‐2,3′‐indolin]‐2‐imines with good functional‐group tolerance.
Direct Synthesis of Multiplexed Metal‐Nanowire‐Based Devices by Using Carbon Nanotubes as Vector Templates
Authors: Clément Pierrick , Xu Xinzhao , Stoppiello Craig T. , Rance Graham A. , Attanzio Antonio , O'Shea James N. , Temperton Robert H. , Khlobystov Andrei N. , Lovelock Kevin R. J. , Seymour Jake M. , Fogarty Richard M. , Baker Alastair , Bourne Richard A. , Hall Brendan , Chamberlain Thomas W. , Palma Matteo 
Published: May 2019

AbstractWe present the synthesis of metal nanowires in a multiplexed device configuration using single‐walled carbon nanotubes (SWNTs) as nanoscale vector templates. The SWNT templates control the dimensionality of the wires, allowing precise control of their size, shape, and orientation; moreover, a solution‐processable approach enables their linear deposition between specific electrode pairs in electronic devices. Electrical characterization demonstrated the successful fabrication of metal nanowire electronic devices, while multiscale characterization of the different fabrication steps revealed details of the structure and charge transfer between the material encapsulated and the carbon nanotube. Overall the strategy presented allows facile, low‐cost, and direct synthesis of multiplexed metal nanowire devices for nanoelectronic applications.
Enantioselective Total Synthesis of (+)‐Jungermatrobrunin A
Authors: Wu Jinbao , Kadonaga Yuichiro , Hong Benke , Wang Jin , Lei Xiaoguang 
Published: May 2019

AbstractA concise and enantioselective total synthesis of (+)‐jungermatrobrunin A (1), which features a unique bicyclo[3.2.1]octene ring skeleton with an unprecedented peroxide bridge, was accomplished in 13 steps by making use of a late‐stage visible‐light‐mediated Schenck ene reaction of (−)‐1α,6α‐diacetoxyjungermannenone C (2). Along the way, a UV‐light‐induced bicyclo[3.2.1]octene ring rearrangement afforded (+)‐12‐hydroxy‐1α,6α‐diacetoxy‐ent‐kaura‐9(11),16‐dien‐15‐one (4). These divergent photo‐induced skeletal rearrangements support a possible biogenetic relationship between (+)‐1, (−)‐2, and (+)‐4.
An Olefinic 1,2‐Boryl‐Migration Enabled by Radical Addition: Construction ofgem‐Bis(boryl)alkanes
Authors: Zhao Binlin , Li Zexian , Wu Yixiao , Wang Yandong , Qian Jiasheng , Yuan Yu , Shi Zhuangzhi 
Published: May 2019

AbstractA series of in situ formed alkenyl diboronate complexes from alkenyl Grignard reagents (commercially available or prepared from alkenyl bromides and Mg) with B2Pin2(bis(pinacolato)diboron) react with diverse alkyl halides by a Ru photocatalyst to give various gem‐bis(boryl)alkanes. Alkyl radicals add efficiently to the alkenyl diboronate complexes, and the adduct radical anions undergo radical‐polar crossover, specifically, a 1,2‐boryl‐anion shift from boron to the α‐carbon sp2center. This transformation shows good functional‐group compatibility and can serve as a powerful synthetic tool for late‐stage functionalization in complex compounds. Measurements of the quantum yield reveal that a radical‐chain mechanism is operative in which the alkenyl diboronates acts as reductive quencher for the excited state of the photocatalyst.
Nickel‐Catalyzed 1,1‐Alkylboration of Electronically Unbiased Terminal Alkenes
Authors: Li Yangyang , Pang Hailiang , Wu Dong , Li Zheqi , Wang Wang , Wei Hong , Fu Ying , Yin Guoyin 
Published: May 2019

AbstractAn unprecedented nickel‐catalyzed 1,1‐alkylboration of electronically unbiased alkenes has been developed, providing straightforward access to secondary aliphatic boronic esters from readily available materials under very mild reaction conditions. The regioselectivity of this reaction is governed by a unique pyridyl carboxamide ligated catalyst, rather than the substrates. Moreover, this transformation shows excellent chemo‐ and regio‐selectivity and remarkably good functional‐group tolerance. We also demonstrate that under balloon pressure, ethylene can also be utilized as a substrate. Additionally, competence experiments indicate that selective bond formation is favored at the α‐position of boron and preliminary mechanistic studies indicate that the key step in this three‐component reaction involves a 1,2‐nickel migration.
Zerlegung der Verdampfungsenthalpien ionischer Flüssigkeiten durch rein experimentelle Methoden: Coulomb‐Wechselwirkung, Wasserstoffbrücken und Dispersionskräfte
Authors: Zaitsau Dzmitry H. , Emel'yanenko Vladimir N. , Stange Peter , Verevkin Sergey P. , Ludwig Ralf 
Published: May 2019

AbstractDie Quantifizierung von Coulomb‐Wechselwirkung, Wasserstoffbrücken und Dispersionskräften in ionischen Flüssigkeiten (ionic liquids, ILs) allein mittels gemessener Verdampfungsenthalpien ist eine große Herausforderung. Die Zusammensetzung der verschiedenen Wechselwirkungen ist weder für die flüssige noch für die gasförmige Phase der ILs bekannt. In dieser Arbeit messen wir die Verdampfungsenthalpien verschiedener alkylierter protischer ionischer Flüssigkeiten (protic ionic liquids, PILs), aprotischer ionischer Flüssigkeiten (aprotic ionic liquids, AILs) und molekularer Analoga ihrer Kationen. Wir zeigen, dass Wasserstoffbrücken die Coulomb‐Wechselwirkung der Ionenpaare in der Gasphase verstärken. Die Gesamtwechselwirkung der ILs in der flüssigen Phase setzt sich zusammen aus Coulomb‐Wechselwirkung (76 kJ mol−1), Wasserstoffbrücken (38 kJ mol−1) und Dispersionswechselwirkung (10 kJ mol−1). Offenbar tragen Wasserstoffbrücken wesentlich zur Gesamtwechselwirkung in PILs bei, was sich in den Eigenschaften dieser Flüssigkeiten widerspiegelt.
Fire‐Safe Polyesters Enabled by End‐Group Capturing Chemistry
Authors: Liu Bo‐Wen , Chen Li , Guo De‐Ming , Liu Xiao‐Feng , Lei Yu‐Fei , Ding Xiao‐Min , Wang Yu‐Zhong 
Published: May 2019

AbstractUpon heating, polyesters decompose to small molecules and release flammable volatiles and toxic gases, primarily through chain scission of their ester linkages, and therefore exhibit poor fire‐safety properties, thus restricting their applications. Reported herein is an end‐group‐capturing effect of (bis)oxazoline groups, generated from the thermal rearrangement of the N‐(2‐hydroxyphenyl)phthalimide (HPI) moiety which was incorporated into the polyester chain by copolymerization. These copolyesters, as a result, exhibit high efficiency in retarding decomposition by capturing the decomposed products, particularly for the carbonyl‐terminated fragments, thus increasing the fire‐safety properties, such as self‐extinguishing, anti‐dripping, and inhibiting heat release and smoke production. The successful application of this method in both semi‐aromatic and aliphatic polyesters provide promising perspectives to designing versatile fire‐safe polymers.
Synthetic Lugdunin Analogues Reveal Essential Structural Motifs for Antimicrobial Action and Proton Translocation Capability
Authors: Schilling Nadine A. , Berscheid Anne , Schumacher Johannes , Saur Julian S. , Konnerth Martin C. , Wirtz Sebastian N. , Beltrán‐Beleña José M. , Zipperer Alexander , Krismer Bernhard , Peschel Andreas , Kalbacher Hubert , Brötz‐Oesterhelt Heike , Steinem Claudia , Grond Stephanie 
Published: May 2019

AbstractLugdunin, a novel thiazolidine cyclopeptide, exhibits micromolar activity against methicillin‐resistant Staphylococcus aureus (MRSA). For structure–activity relationship (SAR) studies, synthetic analogues obtained from alanine and stereo scanning as well as peptides with modified thiazolidine rings were tested for antimicrobial activity. The thiazolidine ring and the alternating d‐ and l‐amino acid backbone are essential. Notably, the non‐natural enantiomer displays equal activity, thus indicating the absence of a chiral target. The antibacterial activity strongly correlates with dissipation of the membrane potential in S. aureus. Lugdunin equalizes pH gradients in artificial membrane vesicles, thereby maintaining membrane integrity, which demonstrates that proton translocation is the mode of action (MoA). The incorporation of extra tryptophan or propargyl moieties further expands the diversity of this class of thiazolidine cyclopeptides.
Non‐Thermoresponsive Decanano‐sized Domains in Thermoresponsive Hydrogel Microspheres Revealed by Temperature‐Controlled High‐Speed Atomic Force Microscopy
Authors: Nishizawa Yuichiro , Matsui Shusuke , Urayama Kenji , Kureha Takuma , Shibayama Mitsuhiro , Uchihashi Takayuki , Suzuki Daisuke 
Published: May 2019

AbstractDespite the tremendous efforts devoted to the structural analysis of hydrogel microspheres (microgels), many details of their structures remain unclear. Reported in this study is that thermoresponsive poly(N‐isopropyl acrylamide) (pNIPAm)‐based microgels exhibit not only the widely accepted core–shell structures, but also inhomogeneous decanano‐sized non‐thermoresponsive spherical domains within their dense cores, which was revealed by temperature‐controlled high‐speed atomic force microscopy (TC‐HS‐AFM). Based on a series of experiments, it is concluded that the non‐thermoresponsive domains are characteristic for pNIPAm microgels synthesized by precipitation polymerization, and plausible structures for microgels prepared by other polymerization techniques are proposed.
Dissecting the Vaporization Enthalpies of Ionic Liquids by Exclusively Experimental Methods: Coulomb Interaction, Hydrogen Bonding, and Dispersion Forces
Authors: Zaitsau Dzmitry H. , Emel'yanenko Vladimir N. , Stange Peter , Verevkin Sergey P. , Ludwig Ralf 
Published: May 2019

AbstractThe quantification of hydrogen bonding and dispersion energies from vaporization enthalpies is a great challenge. Dissecting interaction energies is particularly difficult for ionic liquids (ILs), for which the composition of the different types of interactions is known neither for the liquid nor for the gas phase. In this study, we demonstrate the existence of ion pairs in the gas phase and dissect the interaction energies exclusively from measured vaporization enthalpies of different alkylated protic ILs (PILs) and aprotic ILs (AILs) and the molecular analogues of their cations. We demonstrate that the evaporated ion pairs are characterized by H‐bond‐enhanced Coulomb interaction. The overall interaction energy for the ILs in the bulk phase is composed of Coulomb interaction (76 kJ mol−1), hydrogen bonding (38 kJ mol−1), and minor dispersion interaction (10 kJ mol−1). Thus, hydrogen bonding prominently contributes to the overall interaction energy of PILs, which is reflected in the properties of this class of liquids.
Synthesis and Characterization of Cyclopropaosmanaphthalenes Containing a Fused σ‐Aromatic Metallacyclopropene Unit
Authors: Chu Zhenwei , He Guomei , Cheng Xiaoli , Deng Zhirong , Chen Jiangxi 
Published: May 2019

AbstractMetalla‐aromatics are important complexes that show unique properties owing to their highly conjugated systems, which show Hückel or Möbius aromaticity. Recently, several metalla‐aromatics showing spiro‐aromaticity or σ‐aromaticity have been reported. Herein, we report the isolation of the first cyclopropametallanaphthalenes, in which the metallacyclopropene ring shows σ‐aromaticity and weak hyperconjugative aromaticity. The reaction of OsCl2(PPh3)3 with o‐ethynylphenyl alkynes in the presence of PPh3 followed by protonation with HCl yielded the first cyclopropametallanaphthalenes. The reaction mechanism and the aromaticity were also investigated by density functional theory studies.
Liquid–Liquid Equilibrium for Systems Containing Epoxidized Oils, Formic Acid, and Water: Experimental and Modeling
Authors: Fang Jiaojiao , Zheng Ting , Wu Zhenyu , Wu Lihang , Xie Qinglong , Xia Fan , Lu Meizhen , Nie Yong , Ji Jianbing 
Published: May 2019

AbstractEpoxidized oils are eco‐friendly plasticizers, which are industrially produced through the epoxidation reaction in a formic acid‐hydrogen peroxide autocatalyzed system. The fundamental knowledge to describe the phase equilibrium of systems after epoxidation reaction is lacking, which is crucial for the design of the purification facilities. This work reported experimental data for the liquid–liquid equilibrium of three systems, i.e., epoxidized fatty acid methyl esters + formic acid + water, epoxidized fatty acid 2‐ethylhexyl esters + formic acid + water, and epoxidized soybean oil + formic acid + water, in the temperature range (303.15–348.15) K under atmospheric pressure. The results indicated that the liquid–liquid equilibrium constant of formic acid in the systems followed the order of epoxidized fatty acid 2‐ethylhexyl esters > epoxidized fatty acid methyl esters > epoxidized soybean oil. Moreover, the obtained experimental data were correlated using nonrandom two liquid (NRTL) and universal quasi chemical (UNIQUAC) models. The maximum root mean square deviation (RMSD) values as low as 0.0052 and 0.0263 were estimated using the NRTL and UNIQUAC model, respectively. The NRTL model is more suitable than the UNIQUAC model to describe the liquid–liquid equilibrium behavior of these ternary systems.
Developing of a monitoring system for evaluating and investigating the fired heater performance
Authors: Elsaid Mahmoud R. , Shoaib Abeer M. , Bhran Ahmed A. , Awad Mostafa E. 
Published: May 2019

AbstractEnergy costs represent about 65% of the running cost of a chemical, petrochemical, or refining plant. Furnace fuel represents the largest percent of this cost as it consumes large amounts of fuel to produce the necessary heat duty. Therefore, it is important for fired heaters to have an efficient system for monitoring operational parameters to reach the optimum performance and minimum stack emissions with an acceptable safety levels. One of the most critical operational parameters to be measured is the tube metal temperature (TMT) inside the radiation section. Excessive TMT can accelerate tube creep, hydrogen attack, and external and internal corrosion of the tube wall. The objective of this work is to develop a program capable of calculating precisely and continuously TMT instead of using external pyrometers that measure it only at certain times for heaters not equipped with thermocouples. The program can also be a predictive tool for estimating the changes of TMT at various temporarily conditions such as raising the fired heater capacity. Four case studies were investigated; the results showed a good agreement between the actual results and the proposed program results with a maximum deviation lower than 6%, which indicates the validity of the introduced program.
Pressure swing distillation for the separation of methyl acetate‐methanol azeotrope
Authors: Wang Keliang , Li Jing , Liu Ping , Lian Minglei , Du Tingzhao 
Published: May 2019

AbstractPressure swing distillation (PSD) process was used to separate methyl acetate‐methanol azeotrope. Through the phase diagram analysis, distillation sequence and technological process were determined. On the basis of the principle of the minimum total annual cost (TAC), design variables such as feeding position, reflux ratio, and column plate number were optimized and the optimal parameters were determined. The high‐pressure column (HPC) under various pressures were analysed. The economic results of the PSD without heat integration, with partial heat integration, and with full heat integration were compared. The comparison results indicate that the TAC of the PSD without heat integration is the highest. The PSD with partial integration and full heat integration can effectively reduce the total capital cost and total operating cost. Compared with the PSD without heat integration, the TACs of partial heat integration and full heat integration exhibit 27% and 30% savings, respectively. Therefore, the PSD with full heat integration is more economically reasonable for separating methyl acetate‐methanol azeotrope.
Identification of essential habitats: Including chimaeras into current shark protected areas
Authors: Barnett Adam , McAllister Jamie D. , Semmens Jayson , Abrantes Kátya , Sheaves Marcus , Awruch Cynthia 
Published: May 2019

Abstract

Essential habitats are areas required to support specific functions, such as providing foraging grounds, shelter or used for reproductive purposes. For mobile aquatic species that move throughout numerous components of the seascape, identifying essential habitats within a species' broader distribution range is crucial to understanding their ecology and provide vital information needed to underpin effective conservation and management (e.g. the implementation of protected areas).
In Tasmania (Australia), a number of coastal habitats have been declared shark refuge areas (SRAs), where fishing for elasmobranchs (sharks, rays and skates) is prohibited.
Chimaeras are relatives of elasmobranchs (class Chondrichthyes) and share traits that predispose many elasmobranch species to be vulnerable to overfishing (e.g. slow growth rates and low reproductive output). However, fishing for elephantfish Callorhinchus milii (the chimaera species found in coastal Tasmania) is still permitted in SRAs.
Here, a combination of acoustic tracking, catch data and reproductive information was used to determine the significance of the SRA coastal habitats for C. milii.
Results suggest that these areas are essential habitats for reproduction and likely important for other purposes, such as foraging.
Given that a key strategy in managing fish stocks is protecting areas important for reproduction, and the importance of these coastal areas of Tasmania for C. milii reproductive purposes, we recommend including C. milii in current SRAs, and decreeing these areas as chondrichthyan refuge areas.
Evaluating the efficacy of the mollusc Tridacna crocea for reconstructing ancient sea‐surface temperatures in the Rock Islands of Palau, Micronesia
Authors: JEW NICHOLAS P. , DODRILL TAYLOR , FITZPATRICK SCOTT M. 
Published: May 2019

ABSTRACTPrevious stable isotope studies for shellfish collected in waters surrounding the Palauan archipelago (north‐western tropical Pacific) have demonstrated that various local shellfish taxa may be reliable recorders of their ambient water temperatures from modern and archaeological contexts. In this study, we analysed stable oxygen isotope (δ18O) signatures of Tridacna crocea from the archaeological site of Metuker ra Bisech (B:IR‐2:24) to reconstruct average nearshore sea‐surface temperatures (SST) from two components dated to c.560 and 120 calBP. Modern shellfish samples and environmental data were collected from intertidal zones on nearby Orrak Island to provide a modern analogue. These shells were tested using X‐ray diffraction to ensure no secondary recrystallisation of the aragonitic structure. Uncontaminated samples were measured for δ18O to pair with recorded SST. The most appropriate oxygen isotope‐to‐SST conversion formula was then applied to δ18O signatures from archaeological T. crocea to estimate SST averages. The results of this study indicate that T. crocea accurately records ambient SST and is a good proxy for palaeotemperature reconstruction. Our results were compared to previous isotopic studies on Palauan taxa collected to identify regional changes to SST through time, thus allowing for comparisons between human subsistence practices, resource availability and past palaeoenvironments.
Historische Stahlstütze im Visier des Brandschutzes
Authors: Paliga Karen , Köllner Jana 
Published: May 2019

AbstractDie alte Lokhalle 21 im brandenburgischen Wildau wird bald wieder mit Leben gefüllt. In der historischen Industriehalle entsteht eine flexible Mischnutzung aus Verkauf, Gewerbe und Büro‐ und Praxisflächen sowie individuellen Umgebungen für Künstler und Kreative. Aufgrund der geplanten Nutzungsänderung kann ein Bestandsschutz nicht geltend gemacht werden, sodass die Bauteile nach aktuellem Baurecht beurteilt werden müssen. Im vorliegenden Beitrag wird die brandschutztechnische Bemessung einer Fachwerkstütze aus historischem Stahl beschrieben, die Bestandteil eines bestehenden Tragwerks der Halle ist. Generell besteht die im Bestand vorhandene Hallentragstruktur aus Fachwerkstützen und Fachwerkdachbindern. Die Fachwerkkonstruktion der Stahlstützen soll ohne eine brandschutztechnische Beschichtung oder Bekleidung im Bestand belassen werden. Der Bericht bewertet die Feuerwiderstandsfähigkeit der Stahlstütze auf Grundlage eines repräsentativen Naturbrandszenarios unter Berücksichtigung der Materialeigenschaften von historischem Stahl. Weiterhin werden Maßnahmen für die Fachwerkstütze entwickelt, um die brandschutztechnischen Anforderungen zu erfüllen.