bluuebunny/crossref_metadata_2025 huggingface dataset:
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

We 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

A 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

A 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

An 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

Die 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

Upon 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

Lugdunin, 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

Despite 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

The 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

Metalla‐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.
In situpreparation and characterization of novel CuI‐functionalized poly[(methyl methacrylate)‐co‐maleimide] as an efficient heterogeneous catalyst in the regioselective synthesis of 1,2,3‐triazoles via click reaction: Experimental and computational chemistry
Authors: Pourmohammad Nargess , Heravi Majid M. , Ahmadi Shervin , Hosseinnejad Tayebeh
Published: May 2019

A CuI‐functionalized poly[(methyl methacrylate)‐co‐maleimide] (CuI@[PMMA‐co‐MI]) nanocatalyst was prepared fromin situpolymerization and functionalization of poly[(methyl methacrylate)‐co‐(maleic anhydride)] and well characterized using various techniques. From a computational viewpoint, we assessed two complexation models between copper nanoparticles and [PMMA‐co‐MI]. In this line, the metal–ligand interaction strength was also studied via density functional theory calculations and frontier molecular orbital analysis. Moreover, for presenting a quantitative description of the electronic features of immobilization of copper nanoparticles on polymeric support, the topological analysis of electron density and its Laplacian was performed through quantum theory of atoms in molecules. Finally, the catalytic activity of CuI@[PMMA‐co‐MI] as a heterogeneous nanocatalyst was successfully examined in the highly regioselective synthesis of 1,4‐disubstituted 1,2,3‐triazoles via click reaction.
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

Epoxidized 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

Energy 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

Pressure 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

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

Previous 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

Die 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.
There are no safe areas for avoiding the perforating arteries along the proximal part of the femur: A word of caution
Authors: Pretterklieber Bettina , Pablik Eleonore , Dorfmeister Karl , Pretterklieber Michael L.
Published: May 2019

Knowledge about the variable course of the perforating arteries near the body of the femur is essential during surgical procedures (e.g., percutaneous cerclage wiring, plate osteosynthesis, Ilizarov technique). Our aims were to determine the number of perforating arteries, and to identify safe zones along the body of the femur within which perforating arteries are unlikely to pass toward the back of the thigh. The number of perforating arteries was determined in both legs of 100 formalin‐fixed anatomic specimens of both sexes. The level of passage of perforating arteries near the body of the femur was measured in reference to a line from the anterior superior iliac spine to the medial femoral condyle. In each leg, two to seven perforating arteries were present. In 64% of legs, at least one artery divided into two to four branches before entering the back of the thigh. Thus, the total number of branches passing near the body of the femur varied between two to nine. Perforating arteries passed to the back of the thigh at every level between 14.0 and 36.5 cm from the anterior superior iliac spine (16–39% of the leg length). Within this distance, no safe zones along the body of the femur could be identified. The present study shows the high variability regarding number and course of the perforating arteries. Surgeons can be faced with an artery at every level on the posteromedial aspect of the body of the femur between 14.0 and 36.5 cm distally to the anterior superior iliac spine. Clin. Anat. 33:507–515, 2020. © 2019 Wiley Periodicals, Inc.
Molecular profile in Paraguayan colorectal cancer patients, towards to a precision medicine strategy
Authors: Fleitas-Kanonnikoff Tania , Martinez‐Ciarpaglini Carolina , Ayala Josefina , Gauna Cinthia , Denis Rita , Yoffe Ita , Sforza Silvia , Martínez María Teresa , Pomata Alicia , Ibarrola‐Villava Maider , Arevshatyan Sipan , Burriel Verónica , Boscá Diego , Pastor Oscar , Ferrer‐Martinez Ana , Carrasco Francisca , Mongort Cristina , Navarro Samuel , Ribas Gloria , Cervantes Andres
Published: May 2019

Somatic mutation analysis and evaluation of microsatellite instability (MSI) have become mandatory for selecting personalized therapy strategies for advanced colorectal cancer and are not available as routine methods in Paraguay. The aims of this study were to analyze the molecular profile as well as the microsatellite status in a series of advanced colorectal patients from two public hospitals from Paraguay, to introduce these methodologies in the routine practice to guide the therapeutic decisions. Thirty‐six patients diagnosed with advanced colorectal cancer from two referent public hospitals from Paraguay were recruited from May 2017 to February 2018. Sequenom Mass spectrometry, Oncocarta Panel V.1 was applied to analyze the mutational profile from formalin‐fixed paraffin‐embedded samples. The microsatellite status was tested by immunohistochemistry (IHC). The mean age of the patients was 52 years with a range from 20 to 74 years. Eighty‐three percent of the patients included in the study have advanced‐stage tumors at the moment of the diagnosis. Sixteen patients (44.4%) were wild‐type for all the oncogene regions analyzed with the Oncocarta panel. Thirty‐two hot‐spot pathogenic variants on seven oncogenes, among 20 patients (55.6%), were identified, including KRAS, NRAS, BRAF, PI3KCA, FGFR, epidermal growth factor receptor, and PDGFRA. Moreover, 14 (38.8%) of these patients presented pathogenic variants in KRAS/NRAS or BRAF genes that have implications in the clinical practice decisions. Five patients (14%) presented MSI. The IHC study for microsatellite status and the molecular profile analysis through Sequenom mass spectrometry are feasible and useful methods, due to identify those patient candidates for targeted therapies and for the budgetary calculations of the National Health Plans.
Exploring the Substrate Scope of the Bacterial Phosphocholine Transferase AnkX for Versatile Protein Functionalization
Authors: Ochtrop Philipp , Ernst Stefan , Itzen Aymelt , Hedberg Christian
Published: May 2019

Site‐specific protein functionalization has become an indispensable tool in modern life sciences. Here, tag‐based enzymatic protein functionalization techniques are among the most versatilely applicable approaches. However, many chemo‐enzymatic functionalization strategies suffer from low substrate scopes of the enzymes utilized for functional labeling probes. We report on the wide substrate scope of the bacterial enzyme AnkX towards derivatized CDP‐choline analogues and demonstrate that AnkX‐catalyzed phosphocholination can be used for site‐specific one‐ and two‐step protein labeling with a broad array of different functionalities, displaying fast second‐order transfer rates of 5×102 to 1.8×104 m−1 s−1. Furthermore, we also present a strategy for the site‐specific dual labeling of proteins of interest, based on the exploitation of AnkX and the delabeling function of the enzyme Lem3. Our results contribute to the wide field of protein functionalization, offering an attractive chemo‐enzymatic tag‐based modification strategy for in vitro labeling.
Insights into the Nature of the Active Sites of Tin‐Montmorillonite for the Synthesis of Polyoxymethylene Dimethyl Ethers (OME)
Authors: Baranowski Christophe J. , Bahmanpour Ali M. , Héroguel Florent , Luterbacher Jeremy S. , Kröcher Oliver
Published: May 2019

In this study, we report that intercalation of tin into montmorillonite clay (Sn‐MMT) boosts catalytic activity for the synthesis of polyoxymethylene dimethyl ethers, a promising diesel fuel additive. This increase in activity is attributed to the formation of a hierarchical catalyst displaying high surface area with accessible Brønsted and Lewis acid sites. Extensive characterization such as MAS‐NMR, XRD and in‐situ DRIFTS confirmed that tin insertion induced reorganization of the clay layers into a disorganized house‐of‐cards structure. It also revealed that tin resided between the clay layers as defective SnO2 nanocrystals stabilized by the negative charge of MMT. The source of acidity in Sn‐MMT was studied by comparing it with two similar materials, namely Sn(OH)4, and thermally treated Sn‐MMT. Low activity measured for isolated hydroxylated SnO2 nanoparticles illustrates the importance of having clay and tin in close proximity. Meanwhile, deactivation upon thermal treatment occurred via sintering of the tin phase and diffusion of the protons inside the layers. Sn‐MMT acidity is attributed to the combination of Si−OH−Al groups, formed as a by‐product of SnO2 crystallization, and undercoordinated Sn surface sites, stabilized by the negative charge of MMT.
Tailoring Nitrogen‐Doped Carbons as Hosts for Single‐Atom Catalysts
Authors: Büchele Simon , Chen Zupeng , Mitchell Sharon , Hauert Roland , Krumeich Frank , Pérez‐Ramírez Javier
Published: May 2019

The application of nitrogen‐doped carbons (NDCs) as host materials for single‐atom catalysts (SACs) is increasing because of the strong binding affinity of the heteroatom with transition metals. Establishment of the relation between the properties of NDCs, their interaction with metals, and the performance of the resulting catalysts is crucial to guide the design of more effective SACs but has not been critically addressed. Here, a series of NDCs is prepared and studied as hosts for palladium atoms. The amount of nitrogen incorporated primarily depends on the choice of carbon followed by the doping temperature and nitrogen source. Pyridinic and pyrrolic species predominate in all cases, especially at lower doping temperatures. The stabilization of palladium atoms is successful above a critical nitrogen content that depends on the carbon type. Evaluation in the catalytic semi‐hydrogenation of 2‐methyl‐3‐butyn‐2‐ol readily distinguishes the reactivity of single atoms and nanoparticles, which correlates with the electronic properties of palladium described by the average oxidation state. Comparison with SACs based on compositionally‐related carbon nitride hosts shows that similarly high stability and tunability of the metal is achievable over NDCs, despite their lower nitrogen contents and greater heterogeneity of coordination sites.
Synergistic Cu/Pd‐Catalyzed Asymmetric Allenylic Alkylation of Azomethine Ylides for the Construction of α‐Allene‐Substituted Nonproteinogenic α‐Amino Acids
Authors: Liu Hua‐Chao , Hu Yuan‐Zheng , Wang Zuo‐Fei , Tao Hai‐Yan , Wang Chun‐Jiang
Published: May 2019

An unprecedented asymmetric allenylic alkylation of readily available imine esters, which was enabled by a synergistic Cu/Pd catalysis, has been developed. This dual catalytic system possesses good substrate compatibility, delivering a diverse array of nonproteinogenic α‐allenylic α‐mono‐ or α,α‐disubstituted α‐amino acids (α‐AAs) with high yields and generally excellent enantioselectivities. Furthermore, the scalability and practicability of the current synthetic protocol were proven by performing gram‐scale reactions and by the first catalytic asymmetric synthesis of naturally occurring (S)‐γ‐allenic α‐amino acid, respectively.
Simultaneous Determination of Concentration and Enantiomeric Composition of Amino Acids in Aqueous Solution by Using a Tetrabromobinaphthyl Dialdehyde Probe
Authors: Iqbal Shahzad , Yu Shanshan , Jiang Le , Wang Xinjing , Chen Yu , Wang Yalin , Yu Xiaoqi , Pu Lin
Published: May 2019

3,3′‐Diformyl‐1,1′‐bi‐2‐naphthol or its methoxymethyl‐protected derivative is found to undergo a highly selective reaction with excess bromine in CH2Cl2at reflux to give the novel 5,5′,6,6′‐tetrabrominated product (S)‐ or (R)‐2. The observed electrophilic substitution at the 5,5′‐positons of an optically active binaphthyl compound is unprecedented. Unlike unbrominated 3,3′‐diformyl‐1,1′‐bi‐2‐naphthol, which is not suitable for fluorescent recognition in water, compound (S)‐2, in combination with Zn2+, exhibits a highly enantioselective fluorescent response toward amino acids in aqueous solution (HEPES buffer, pH 7.4). It is further found that the condensation product of (R)‐2with tryptophan, (R)‐3, shows dual‐responsive emissions toward amino acids; the short wavelength (λ1=350 nm) emission is sensitive to the concentration of the substrate regardless of the chiral configuration and the long wavelength (λ2>500 nm) emission is highly enantioselective. Thus, the use of (R)‐3allows the simultaneous determination of the concentration and enantiomeric composition of an amino acid sample from one fluorescence measurement.
Treatment of Textile Wastewater by Coagulation–Flocculation Process Using Gossypium herbaceum and Polyaniline Coagulants
Authors: Arulmathi Prakasam , Jeyaprabha Chellappa , Sivasankar Periandavan , Rajkumar Vadivel
Published: May 2019

The present study is carried out to evaluate the performance efficiency of biopolymeric and synthetic polymeric coagulants for the removal of color, chemical oxygen demand (COD), and turbidity from textile industrial wastewater. Shells of Gossypium herbaceum (GHC), a bio‐polymeric coagulant from bio‐waste, and polyaniline coagulants (PAC) (a synthetic polymeric) are chosen for the present study. A Box‐Behnken design (BBD) is employed for the optimization of the effects of the four process variables, such as pH, coagulation dose, contact time, and agitation speed, on the removal of color, COD, and turbidity of the wastewater. Fourier‐transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) are carried out to understand the functional characteristics and surface morphology of the coagulants. The maximum removal of color, COD, and turbidity with GHC is found to be 90.13, 72.96, and 85.48%, respectively, at pH 5.5, coagulant dose 2.2 g L−1, and contact time 35 min, while the maximum removal of color, COD, and turbidity with PAC is found to be 94.38, 91.45, and 89.36%, respectively, at pH 8.0, coagulant dose 1.6 g L−1, and contact time 35 min. The experimental results show that pH and coagulant dose influence the treatment efficiency of GHC and PAC. From the experimental observations, it is concluded that the performance of the biopolymeric coagulant is highly compatible in the treatment of textile industrial wastewater.
Cardiorespiratory fitness and incident lung and colorectal cancer in men and women: Results from the Henry Ford Exercise Testing (FIT) cohort
Authors: Marshall Catherine Handy , Al‐Mallah Mouaz H. , Dardari Zeina , Brawner Clinton A. , Lamerato Lois E. , Keteyian Steven J. , Ehrman Jonathan K. , Visvanathan Kala , Blaha Michael J.
Published: May 2019

Background

To the authors’ knowledge, the relationship between cardiorespiratory fitness (CRF) and lung and colorectal cancer outcomes is not well established.

Methods

A retrospective cohort study was performed of 49,143 consecutive patients who underwent clinician‐referred exercise stress testing from 1991 through 2009. The patients ranged in age from 40 to 70 years, were without cancer, and were treated within the Henry Ford Health System in Detroit, Michigan. CRF, measured in metabolic equivalents of task (METs), was categorized as <6 (reference), 6 to 9, 10 to 11, and ≥12. Incident cancer was obtained through linkage to the cancer registry and all‐cause mortality from the National Death Index.

Results

Participants had a mean age of 54 ± 8 years. Approximately 46% were female, 64% were white, 29% were black, and 1% were Hispanic. The median follow‐up was 7.7 years. Cox proportional hazard models, adjusted for age, race, sex, body mass index, smoking history, and diabetes, found that those in the highest fitness category (METs ≥12) had a 77% decreased risk of lung cancer (hazard ratio [HR], 0.23; 95% CI, 0.14‐0.36) and a 61% decreased risk of incident colorectal cancer (HR, 0.39; 95% CI, 0.23‐0.66; with additional adjustment for aspirin and statin use). Among those diagnosed with lung and colorectal cancer, those with high fitness had a decreased risk of subsequent death of 44% and 89%, respectively (HR, 0.56 [95% CI, 0.32‐1.00] and HR, 0.11 [95% CI, 0.03‐0.37], respectively).

Conclusions

In what to the authors’ knowledge is the largest study performed to date, higher CRF was associated with a lower risk of incident lung and colorectal cancer in men and women and a lower risk of all‐cause mortality among those diagnosed with lung or colorectal cancer.
Effects of Differential Food Patterns on the Pharmacokinetics of Enteric‐Coated Mesalazine Tablets in the Same Cohort of Healthy Chinese Volunteers
Authors: Zhang Su‐hua , Li Yao , Wei Shan‐shan , Guo Lin , Huang Xiao‐mei , Chen Ying , Wu Xiang‐xin , Cai Hua‐lin , Zhang Bi‐kui
Published: May 2019

This study aimed to simultaneously determine mesalazine (5‐ASA) and its major metabolite N‐Ac‐5‐ASA in the plasma and to evaluate the impact of different food patterns on the relative bioavailability and pharmacokinetics of a single oral dose of 5‐ASA in healthy subjects. In this single‐dose, open‐label, 3‐period, 3‐treatment crossover study, the subjects received a single, oral dose of 500‐mg enteric‐coated mesalazine tablet together with either a low‐fat or a high‐fat breakfast or under fasting condition (reference). The pharmacokinetic parameters were determined by noncompartmental methods and analyzed with a linear mixed‐effect model. The geometric least squares mean ratio for the area under the plasma concentration–time curve from zero to infinity of N‐Ac‐5‐ASA was 1.05 (90% confidence interval [CI], 0.70‐1.58) for high‐fat/fasted condition and 1.06 (90%CI, 0.82‐1.36) for low‐fat/fasted condition. The least squares mean ratio of 5‐ASA was 0.86 (90%CI, 0.65‐1.14) for high‐fat/fasted condition and 0.78 (90%CI, 0.60‐1.02) for low‐fat/fasted condition. All P values were >.05. The mean maximum plasma concentration and the time to reach the maximum plasma concentration of N‐Ac‐5‐ASA were 2084 ng/mL, 8 hours; 2639 ng/mL, 11 hours, and 2409 ng/mL, 9 hours for fasted, high‐fat, and low‐fat, respectively. The values of 5‐ASA were 1950 ng/mL, 7 hours; 2869 ng/mL, 9 hours; and 2837 ng/mL, 8 hours for fasted, high‐fat, and low‐fat condition. 5‐ASA was well tolerated under all 3 conditions. Food delayed the absorption of 5‐ASA, especially a high‐fat meal. Therefore, enteric‐coated mesalazine tablets should be taken before meals to avoid causing patients slow response and any effect of food on its efficacy.
A Spark image processing toolkit
Authors: Téllez‐Velázquez Arturo , Cruz‐Barbosa Raúl
Published: May 2019

The main drawback of conventional tools for digital image processing is the long processing time due to the high complexity of their algorithms. This gets worse when these algorithms need to be sequentially processed with large image sets. To alleviate part of this situation, this paper introduces a general‐purpose tool for massively processing large digital image sets by using Apache Spark. The proposed tool allows users to extract the image rasters and store them in any of Spark's basic distributed data representations, namely, Resilient Distributed Datasets (RDD) and DataFrame (DF), to treat all the subsequent image operations as RDD/DF transformations. Our experiments reveal that, with our proposal, it is possible to schedule and execute distributed image processing tasks in less time, in comparison with another Spark‐based massive image processing tool. In these experiments, we applied several algorithms to 25 000 images (the MIRFLICKR‐25000 set), reaching a maximum speedup of 54x. In addition, it was discovered that the number of images also influences the speedup, as the cluster memory is fully occupied. Therefore, we can claim that, using our proposal, more complex image processing workflows can be built and applied massively to large image sets, achieving competitive speedups.
Dynamic social network analysis: A novel approach using agent‐based model, author‐topic model, and pretopology
Authors: Ho Thi Kim Thoa , Bui Quang Vu , Bui Marc
Published: May 2019

We propose in this work a novel approach for dynamic social network analysis by combining an agent‐based model, an author‐topic model, and pretopology. We first introduce an analytical model for a dynamic social network associated with textual content using agent‐based and author‐topic models, namely, Textual‐ABM. The purpose of Textual‐ABM is to support for the concept exploitation of the “dynamics” of a social network, which contains not only network's structure transformation but also agent's interest variation over time. Agent's interest is revealed through topic probability distribution, which is estimated based on textual data using an author‐topic model. In addition to demonstrating the fluctuation of the social network related to textual content, we also exploit information propagation phenomena by proposing two expanded spreading models. The first model is an expanded model of an independent cascade model in which probability of infection is formed on homophily, namely H‐IC. We have implemented experiments on a collected dataset from the Neural Information Processing Systems Conference and have acquired satisfying results. Furthermore, we propose an extended model of pretopological cascade model from our previous work, namely, Textual‐PCM. The advantage of PCM comparison with classical cascade model is to utilize pseudoclosure function built from pretopology to define the more complex set of neighborhoods. In this work, we expand PCM to apply detail for a social network related to textual information. A toy example with some experiments and discussion is illustrated for Textual‐PCM. The work in this paper is an extended version of our paper dynamic social network analysis using author‐topic model presented in I4CS 2018 Conference.
Searching for Diradicaloid Chromophores with Efficient Singlet Fission: Cyano‐Group Substitution of Difuropyrene Systems
Authors: Li Qing , Kan Yu‐He , Wu Xue , Su Zhong‐Min , Xu Hong‐Liang
Published: May 2019

On the basis of theoretical models and calculations, CN‐substituted difuropyrene systems have been investigated as potential singlet fission (SF) candidates for solar cell applications. Calculations indicate that the fusion of difuran and pyrene in different arrangements could introduce variable diradical properties, and the fused compound ab‐trans‐DFP has moderate diradical character (y0=0.45) while satisfying the main condition (ΔE1) of SF. Furthermore, CN‐substituted ab‐trans‐DFP (substituted at distinct positions) is used to adjust the frontier molecular orbital energy level to satisfy the SF secondary condition (ΔE2). Interestingly, the position of the cyano substituents has almost no effect on the diradical character, which can be explained by the insensitivity of the ring aromaticity to the cyano position. Both time dependent density functional theory (TD‐DFT) and multi‐configurational self‐consistent field (MCSCF) results confirm that the 4‐ and 5‐position cyano‐substituted ab‐trans‐DFP derivatives can satisfy the two energy conditions and may become potential SF candidates. This work provides an effective strategy for the rational design of new suitable diradical SF candidates, and it is expected that more polycyclic aromatic hydrocarbons such as pyrene can achieve SF conditions by chemical modification, such as fusion or substitution, to adjust the diradical character and the vertical excitation energy.
Fluorescence pH Probes Based On Photoinduced Electron Transfer Quenching of Long Fluorescence Lifetime Triangulenium Dyes
Authors: Rosenberg Martin , Junker Anne Kathrine R. , Sørensen Thomas Just , Laursen Bo W.
Published: May 2019

The front cover artwork is provided by the Bo W. Laursen group from the University of Copenhagen. The image illustrates the on and off states and the quenching mechanism of a pH‐sensitive phenol‐substituted diazaoxatriangulenium (DAOTA) fluorophore in acidic and basic environments, respectively. Read the full text of the Article at 10.1002/cptc.201800266.
Steps of care for adolescents with anorexia nervosa—A Delphi study
Authors: Buchman Samantha , Attia Evelyn , Dawson Lisa , Steinglass Joanna E.
Published: May 2019

Objective

Anorexia nervosa (AN) commonly develops during adolescence. Existing literature offers some treatment guidelines, but clear clinical criteria for initial recommendations and steps of care are needed. The aim of the present study was to develop expert consensus for a stepped‐care algorithm for treatment of adolescents with AN.

Method

The Delphi approach was used to identify clinical parameters that guide initial treatment recommendations and recommendations for transitions between levels of care. The Delphi approach provides a useful expert consensus when empirical data are limited. Individuals with at least 10 years of experience in the field of adolescent AN and membership in one of three professional organizations were recruited. Twenty‐five panelists participated in three rounds of iterative online questionnaires.

Results

Consensus was achieved on several features of a treatment algorithm. Hospitalization is recommended when medical instability, suicidality, or acute food refusal are present at any point in treatment. Family‐based treatment (FBT) is recommended as the first‐line treatment, with a few exceptions. Consensus was not reached on when to transition from a higher level of care to a lower level of care.

Discussion

Expert opinion was used to develop a consensus‐based algorithm for care of adolescents with AN. Future research is needed to test whether these recommendations can be used to optimize outcomes for adolescents with AN.
An Anionic β‐Diketiminato Oxoborane with a B–O Double Bond
Authors: Liu Jingjing , Yu Jiaxiu , Meng Yinfeng , Jin Lijie , Sun Wei , Hou Lei , Chen Sanping , Zeng Fanlong , Li Anyang , Wang Wenyuan
Published: May 2019

A rigid β‐diketiminate ligand was used to synthesize a cationic hydroxyborane and an anionic oxoborane. The anionic oxoborane has a negatively charged oxo‐group, which possesses a 1.301(3) Å B–O double bond and interacts with the hydrogen bond of an imidazolium cation. Theoretical calculations successfully illustrate the unsaturated nature of the B–O bond and the stability of the conjugated C3N2B‐ring in the oxoborane. The isolation of the new oxoborane compound offers promising approaches to unsaturated boron species.
General Synthesis of Industrial Cephalosporin‐Based Antibiotics Through Amidation with Tosyl Chloride as a Coupling Reagent
Authors: Pieper Matthias , Schleich Herbert , Gröger Harald
Published: May 2019

In this contribution we demonstrate the feasibility of a recently developed amidation method for a general synthesis of industrially important semi‐synthetic cephalosporin antibiotics starting from readily available 7‐aminocephalosporanic acid and derivatives thereof. The amidation process is based on the use of 4‐toluene‐sulfonyl chloride as an economically attractive coupling reagent in combination with methanol or ethyl acetate as one of the solvent components. A broad reaction scope was shown by the successful synthesis of three further cephalosporin antibiotics with different functionalities, which were obtained in high yields of 82–95 % in the reactions even under non‐optimized conditions. It is noteworthy that also different oxime functionalities in the side chain of the 7′‐position are tolerated as well as an ester moiety in 4′‐position and a cationic functionality in 3′‐position. Thus, this amidation process through an activated anhydride formed by means of 4‐toluenesulfonyl chloride is a broadly applicable methodology for the synthesis of industrial semi‐synthetic cephalosporin antibiotics.
Deoxyradiofluorination Reaction from β‐Hydroxy‐α‐aminoesters: an Entry to [18F]Fluoroaminoesters under Mild Conditions
Authors: Morlot Marine , Gourand Fabienne , Perrio Cécile
Published: May 2019

We report the conversion of β‐hydroxy‐α‐aminoesters derived from serine, α‐methylserine or β‐phenylserine to the corresponding [18F]fluorinated α or β‐aminoesters by deoxyradiofluorination using [18F]fluoride. The method involved the ring opening of an aziridinum intermediate formed in situ in the presence of a base after activation of the alcohol function with triflic anhydride. The overall process was carried out at room temperature. Both the efficiency and the regioselectivity of the reaction were found to be dependent on the starting substrates. [18F]Fluoroaminoesters were obtained in radiochemical yields ranging from 10–75 %. No improvement was observed for reactions carried out under heating.