bluuebunny/crossref_metadata_2025 huggingface dataset:
Ionic Gel Modulation of RKKY Interactions in Synthetic Anti‐Ferromagnetic Nanostructures for Low Power Wearable Spintronic Devices
Authors: Yang Qu , Zhou Ziyao , Wang Liqian , Zhang Hongjia , Cheng Yuxin , Hu Zhongqiang , Peng Bin , Liu Ming
Published: April 2018

To meet the demand of developing compatible and energy‐efficient flexible spintronics, voltage manipulation of magnetism on soft substrates is in demand. Here, a voltage tunable flexible field‐effect transistor structure by ionic gel (IG) gating in perpendicular synthetic anti‐ferromagnetic nanostructure is demonstrated. As a result, the interlayer Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction can be tuned electrically at room temperature. With a circuit gating voltage, anti‐ferromagnetic (AFM) ordering is enhanced or converted into an AFM–ferromagnetic (FM) intermediate state, accompanying with the dynamic domain switching. This IG gating process can be repeated stably at different curvatures, confirming an excellent mechanical property. The IG‐induced modification of interlayer exchange coupling is related to the change of Fermi level aroused by the disturbance of itinerant electrons. The voltage modulation of RKKY interaction with excellent flexibility proposes an application potential for wearable spintronic devices with energy efficiency and ultralow operation voltage.
Biocatalytic Process for (−)‐Ambrox Production Using Squalene Hopene Cyclase
Authors: Eichhorn Eric , Locher Esther , Guillemer Sabrina , Wahler Denis , Fourage Laurent , Schilling Boris
Published: April 2018

Alicyclobacillus acidocaldarius Squalene Hopene Cyclase was evolved to a biocatalyst suitable for (−)‐Ambrox production at industrial scale. One round of random mutagenesis led to the identification of three variants with (E,E)‐homofarnesol conversion properties improved about 1.5‐ to 10‐fold over that of the wild type enzyme. Eight distinct amino acid mutations were identified overall; only one mutation was at the active site of the enzyme. Each of the three variants contained only two or three mutations over the 631 amino acids of the Alicyclobacillus acidocaldarius Squalene Hopene Cyclase polypeptide chain. Mutations responsible for improved (E,E)‐homofarnesol conversion were identified. Investigations on reaction conditions led to the selection of one variant, with which reaction parameters were optimized towards process‐relevant conditions. A whole cell biotransformation process is presented in which Escherichia coli cells producing an improved Squalene Hopene Cyclase variant allows the conversion of 125 g/L (E,E)‐homofarnesol in ≤72 hours. The developed process for the production of the fragrance ingredient (−)‐Ambrox as Ambrofix® expands the biocatalysis toolbox by setting out a general basis for biocatalytic Squalene Hopene Cyclase cyclization reactions at industrial scale.

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CuI‐Catalyzed Selective 3‐Alkylation of Indoles with N‐Tosylhydrazones and the I2‐Mediated Further Cyclization to Chromeno[2,3‐b]Indoles
Authors: Miao Chun‐Bao , Sun Yan‐Fang , Wu He , Sun Xiao‐Qiang , Yang Hai‐Tao
Published: April 2018

The CuI‐catalyzed reaction of indoles with N‐tosylhydrazones derived from the ortho‐/para‐hydroxybenzaldhydes affords selectively the C‐3 alkylated products rather than the N‐alkylated products. In addition, the I2‐mediated cyclization of the generated C‐3 alkylated products allows the concise synthesis of chromeno[2,3‐b]indole derivatives.

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Phase Behavior of Lipid Bilayers: A Dissipative Particle Dynamics Simulation Study
Authors: Lu Teng , Guo Hongxia
Published: April 2018

Mesoscale simulations are performed to investigate the phase behavior of double‐tail lipid bilayers as a function of temperature and head‐group interaction. Depending on the lipid structure, the simulations reproduce the experimental phase diagrams including the interdigitated structure found in the experimental research. The area per surfactant, the bilayer thickness, the orientational order parameters and the chain overlap parameter are computed and the results show how they depend on the surfactant structure and temperature. The interdigitated structure is induced by increasing the strength of the repulsive interaction between the head‐groups. Therefore, the ability of the model to clarify some of the experimental questions related to the structure of the bilayer, including the interdigitated structure, and to guide the experimental research is confirmed.
Molecular weight monitoring of poly(2‐[[4‐(dimethylamino)benzylidene]amino]phenol) depending on polymerization conditions: investigation of thermal stability, antimicrobial properties, and conductivity enhancement
Authors: Yılmaz Baran Nuray , Saçak Mehmet
Published: April 2018

A novel polyphenol with azomethine group, Poly(2‐[[4‐(dimethylamino)benzylidene]amino]phenol) P(2‐DBAP), was synthesized by oxidative polycondensation of 2‐[[4‐(dimethylamino)benzylidene]amino]phenol) (2‐DBAP) using NaOCl, H2O2, and O2 oxidants in aqueous alkaline medium. The effects of oxidant type and concentration, monomer concentration and polymerization temperature and time on yield and molecular weight distribution of P(2‐DBAP) were investigated. The structures of 2‐DBAP and P(2‐DBAP) were confirmed by UV‐Vis, FTIR, and 1HNMR techniques. Thermal behavior of the polymer was also analyzed by TG‐DTG techniques. Electrical conductivity value of P(2‐DBAP) which was doped with iodine for 24 hr at 60°C was measured as 7 × 10−2 S/cm by increasing 1010 fold compared with its undoped form. This conductivity level is the highest value reported in the literature for polyphenols containing azomethine group. Additionally, antimicrobial activities of 2‐DBAP and P(2‐DBAP) were tested against Sarcina lutea, Enterobacter aerogenes, Escherichia coli, Enterococcus Feacalis, Klebsiella pneumoniae, and Bacillus subtilis bacteria and Candida albicans and Saccharomyces cerevisiae fungi.
Nontoxic, Eco‐friendly Fully Water‐Induced Ternary Zr–Gd–O Dielectric for High‐Performance Transistors and Unipolar Inverters
Authors: Zhu Li , He Gang , Li Wendong , Yang Bing , Fortunato Elvira , Martins Rodrigo
Published: April 2018

In this context, a simple, nontoxic, and eco‐friendly fully water‐induced (WI) route to fabricate ternary ZrGdOx thin films at various annealing temperatures is reported. Annealing temperature dependent microstructure, morphology, optical, electrical properties, and chemical bonding states of the WI ZrGdOx thin films are investigated by x‐ray diffraction, atomic force microscopy, optical spectroscopy, x‐ray photoelectron spectroscopy, and electrical measurements. A low leakage current density of 10−8 A cm−2 at 1 mV cm−1 and a large areal capacitance of 531 nF cm−2 at 20 Hz are observed for 400 °C‐annealed ZrGdOx thin films. To verify the possible applications of ZrGdOx thin films as the gate dielectric in thin‐film transistors (TFTs), WI In2O3/ZrGdOx TFTs are integrated. 250 °C‐derived full oxide In2O3/ZrGdOx TFTs have demonstrated high electrical performance and low operating voltage, including high µFE of 18.82 cm2 V−1 S−1, threshold voltage shift of 0.46 V under positive bias stress for 3600 s, and a large Ion/Ioff of 6.01 × 107, respectively. Finally, a low voltage resistor‐loaded unipolar inverter is built using In2O3/ZrGdOx TFT, exhibiting a linear relationship between supplied voltage and gain voltage and a maximum gain of 7.4 at 2.5 V. These optimized parameters have achieved a low operating voltage of 2 V, which represents a great step toward the achievement of low‐cost, low‐power consumption, and large‐area all‐oxide flexible electronics.
Efficient Passivation of Hybrid Perovskite Solar Cells Using Organic Dyes with COOH Functional Group
Authors: Li Xing , Chen Chun‐Chao , Cai Molang , Hua Xin , Xie Fengxian , Liu Xiao , Hua Jianli , Long Yi‐Tao , Tian He , Han Liyuan
Published: April 2018

Organic–inorganic halide perovskites are efficient absorbers for solar cells. Nevertheless, the trap states at the surfaces and grain boundaries are a detrimental factor compromising the device performance. Here, an organic dye (AQ310) is employed as passivator to reduce the trap states of the perovskites and promote better stability. The results demonstrate that the trap states of perovskite are minimized by the presence of AQ310's COOH group and the formation of coordination with under‐coordinated Pb2+ ions. The resulting carrier recombination time is prolonged and verified by the photoluminescence and open‐circuit voltage decay measurements. Consequently, the best average power conversion efficiency (PCE) of 19.43% is achieved for the perovskite solar cell (PSC) with AQ310 passivation, as compared with a low average PCE of 17.98% for the PSC without AQ310 passivation.
Geriatric medicine in China: The past, present, and future
Authors: Yu Pulin , Liu Xiang , Wang Jianye
Published: April 2018

Geriatric medicine in China started to develop as a medical specialty in the 1950s and has now become an extensive national healthcare network for the elderly. As population aging accelerates and the number of senior citizens keeps rising, major issues of healthcare delivery for this segment need to be addressed. Inequality in access to quality health care continues to exist between the public and private sectors and between urban centers and rural areas. The education and practice of geriatric medicine also face a range of problems, such as inadequate teaching of geriatrics‐related subjects in the medical education curriculum, the design of residency and fellowship programs, and the integration of geriatric principles into clinical practice. Government commitment, investment from the private sector, and improvement in geriatric medicine professionals’ knowledge and skills are required to bring geriatric care to a higher level.
Dialium seed coprophagy in wild western gorillas: Multiple nutritional benefits and toxicity reduction hypotheses
Authors: Masi Shelly , Breuer Thomas
Published: April 2018

Unraveling the relationship between the unusual feeding behaviors and the nutritional intake of endangered species may provide crucial information for understanding species response to habitat unpredictable changes. Primates occasionally re‐ingest fruit seeds alongside ingestion of feces, a behavior called coprophagy. The nutritional benefit is one of the several non‐mutual exclusive hypotheses proposed to explain this behavior. We investigated the ecological correlates of coprophagy in wild western gorillas. We tested whether coprophagy occurred during periods of lower fruit availability and whether it led to higher nutrient intake in comparison to the other food. Data integrated phenological, fecal and nutritional analyses of gorilla food with behavioral observations collected at two sites in Central Africa (Mbeli Bai: ad libitum observations on 15 groups/solitary males, October 2002–November 2005; Bai Hokou: 5‐min scan on a habituated group, December 2004–December 2005). Coprophagy occurred at the end of the high‐fruiting season in association of two Dialium species. Coprophagy correlated positively with the occurrence of Dialium spp. fruit in gorilla feces and in the feeding scans, and showed a positive trend with Dialium availability but not with total fruit availability. Nutritional comparison of Dialium seeds with other important gorilla food showed higher fat and mineral content, particularly of Mg, but also of phenols and tannins in Dialium seeds. We discuss how the effect of gut processing and gut heat via coprophagy may act as cooking‐like effect: increasing the ability to maximize nutrient intake by concurrently softening fibers and decreasing the toxic effect of antifeedants, like in human traditional cooking. Our results support both the multiple nutritional benefit hypothesis and the toxicity reduction hypothesis. Since Dialium is precious timber, the importance of this tree for the critically endangered western gorillas should be taken with high consideration when planning controlled logging of degraded forests or in face of habitat changes.
Flexibility in positional behavior, strata use, and substrate utilization among Bale monkeys (Chlorocebus djamdjamensis) in response to habitat fragmentation and degradation
Authors: Mekonnen Addisu , Fashing Peter J. , Sargis Eric J. , Venkataraman Vivek V. , Bekele Afework , Hernandez‐Aguilar R. Adriana , Rueness Eli K. , Stenseth Nils Chr.
Published: April 2018

Studies of the effects of habitat fragmentation and degradation on primate positional behavior, strata use, and substrate utilization offer valuable insights into the behavioral and ecological flexibility of primates whose habitats have undergone extensive anthropogenic disturbance. In this study, we evaluated how positional behavior, strata use, and substrate utilization differed between Bale monkeys (Chlorocebus djamdjamensis)—bamboo‐eating cercopithecids endemic to the southern Ethiopian Highlands—occupying continuous versus fragmented forests. Bale monkeys in forest fragments (where bamboo had been degraded or eradicated) spent significantly more time on the ground and in understory strata whereas those in continuous forest spent significantly more time in the middle and upper strata. Bale monkeys in forest fragments also spent significantly more time walking and galloping and significantly less time climbing than those in continuous forest. Our results suggest that, unlike the primarily arboreal Bale monkeys in continuous forest, Bale monkeys in forest fragments should be characterized as semi‐terrestrial. In response to habitat disturbance in fragments, we observed a greater emphasis on terrestrial foraging and travel among Bale monkeys in these human altered habitats, which may put them at greater risk of predation and conflict with nearby human populations. Bale monkeys in fragments exhibit flexibility in their positional behavioral repertoire and their degree of terrestriality is more similar to their sister taxa in Chlorocebus than to Bale monkeys in continuous forest. These findings suggest that habitat alteration may compel Bale monkeys to exhibit semi‐terrestrial behaviors crucial for their persistence in human‐modified habitats. Our results contribute to a growing body of literature on primate behavioral responses to anthropogenic modification of their habitats and provide information that can contribute to the design of appropriate conservation management plans.
Stable isotopic evidence for land use patterns in the Middle Euphrates Valley, Syria
Authors: Sołtysiak Arkadiusz , Schutkowski Holger
Published: April 2018

Objectives

Stable carbon and nitrogen isotope ratios (δ13C and δ15N) were used to reconstruct the history of subsistence strategies in the middle Euphrates valley, NE Syria, in six temporal subsets dating from the Early Bronze Age (c. 2300 BCE) to the Modern period (19th/20th century CE). The study aims to demonstrate that changes in political and social organization over time, for which the archaeological record suggests different goals of land use and modes of production, register through dietary patterns that are reflected in isotopic data.

Materials and methods

173 dentin samples were taken from human individuals buried at three sites (Tell Ashara, Tell Masaikh and Gebel Mashtale) together with 15 animal bone samples. Distribution of the δ13C and δ15N values in collagen was interpreted in diachronic perspective, and with regard to lifetime shifts between childhood and adolescence.

Results

Diachronically, isotope signatures indicate a clear decrease in δ15N values accompanied by a small shift in δ13C values between the Old Babylonian (c. 1800–1600 BCE) and the Neo‐Assyrian (c. 850–600 BCE) subsets. A major shift in δ13C values occurred between the Early Islamic (c. 600–1200 CE) and Modern (c. 1800–1950) periods. Ontogenetic changes only occur in a few individuals, but these suggest change of residence between childhood and adolescence.

Discussion

The depletion in 15N from the Neo‐Assyrian period onwards is best explained in terms of a shift from intensive to extensive farming, triggered by the fall of regional city‐states after the Old Babylonian period and the formation of large supra‐regional polities in the Neo‐Assyrian period and later. The enrichment in 13C during the Modern period was most likely the effect of more widely utilizing the dry steppes, abundant in C4 plants, as pasture.
Compatible ecological niche signals between biological and archaeological datasets for late‐surviving Neandertals
Authors: Bible Rachael C. , Peterson A. Townsend
Published: April 2018

Objectives

To assess ecological niche similarity for biological and archaeological samples representing late‐surviving Neandertals in Europe to evaluate the validity of combining these two types of data in ecological niche modeling analyses.

Materials and methods

Tests of niche conservatism were used to assess niche similarity and niche identity of samples of morphologically diagnostic Neandertal remains and Middle Paleolithic (MP) archaeological sites dating to the time period leading up to Neandertal extinction. Paleoenvironmental reconstructions for the Pre‐H4 (43.3–40.2 ky cal BP) were used as environmental space analyses.

Results

Null hypotheses of niche similarity and identity of the two types of samples could not be rejected.

Conclusions

As primary and secondary evidence of Neandertal occurrence during the Pre‐H4 show high levels of niche similarity and identity, combining the two types of occurrence data to create larger samples for niche analyses is justified without the concern that different environmental signals could complicate future research.
Newborn screening: A disease‐changing intervention for glutaric aciduria type 1
Authors: Boy Nikolas , Mengler Katharina , Thimm Eva , Schiergens Katharina A. , Marquardt Thorsten , Weinhold Natalie , Marquardt Iris , Das Anibh M. , Freisinger Peter , Grünert Sarah C. , Vossbeck Judith , Steinfeld Robert , Baumgartner Matthias R. , Beblo Skadi , Dieckmann Andrea , Näke Andrea , Lindner Martin , Heringer Jana , Hoffmann Georg F. , Mühlhausen Chris , Maier Esther M. , Ensenauer Regina , Garbade Sven F. , Kölker Stefan
Published: April 2018

Objective

Untreated individuals with glutaric aciduria type 1 (GA1) commonly present with a complex, predominantly dystonic movement disorder (MD) following acute or insidious onset striatal damage. Implementation of GA1 into newborn screening (NBS) programs has improved the short‐term outcome. It remains unclear, however, whether NBS changes the long‐term outcome and which variables are predictive.

Methods

This prospective, observational, multicenter study includes 87 patients identified by NBS, 4 patients missed by NBS, and 3 women with GA1 identified by positive NBS results of their unaffected children.

Results

The study population comprises 98.3% of individuals with GA1 identified by NBS in Germany during 1999–2016. Overall, cumulative sensitivity of NBS is 95.6%, but it is lower (84%) for patients with low excreter phenotype. The neurologic outcome of patients missed by NBS is as poor as in the pre‐NBS era, and the clinical phenotype of diagnosed patients depends on the quality of therapeutic interventions rather than noninterventional variables. Presymptomatic start of treatment according to current guideline recommendations clearly improves the neurologic outcome (MD: 7% of patients), whereas delayed emergency treatment results in acute onset MD (100%), and deviations from maintenance treatment increase the risk of insidious onset MD (50%). Independent of the neurologic phenotype, kidney function tends to decline with age, a nonneurologic manifestation not predicted by any variable included in this study.

Interpretation

NBS is a beneficial, disease‐changing intervention for GA1. However, improved neurologic outcome critically depends on adherence to recommended therapy, whereas kidney dysfunction does not appear to be impacted by recommended therapy. Ann Neurol 2018;83:970–979
Engineering von Proteinen an Oberflächen: Von komplementärer Charakterisierung zu Materialoberflächen mit maßgeschneiderten Funktionen
Authors: Morsbach Svenja , Gonella Grazia , Mailänder Volker , Wegner Seraphine , Wu Si , Weidner Tobias , Berger Rüdiger , Koynov Kaloian , Vollmer Doris , Encinas Noemí , Kuan Seah Ling , Bereau Tristan , Kremer Kurt , Weil Tanja , Bonn Mischa , Butt Hans‐Jürgen , Landfester Katharina
Published: April 2018

Sobald Materialien mit einer biologischen Flüssigkeit, die Proteine enthält, in Kontakt kommen, werden Proteine im Allgemeinen – ob gewünscht oder nicht – von der Oberfläche des Materials angezogen und adsorbieren darauf. Das Ziel dieses Aufsatzes ist es, einen Überblick über die am häufigsten verwendeten Charakterisierungsmethoden zu geben, um ein besseres Verständnis der Adsorptionsprozesse auf planaren oder gekrümmten Oberflächen zu erhalten. Wir zeigen weiterhin den Vorteil der Kombination verschiedener Methoden, um auf unterschiedliche Oberflächengeometrien des Materials zuzugreifen. Die so erhaltenen Erkenntnisse ebnen idealerweise den Weg für die Entwicklung funktioneller Materialien, die in einer vorbestimmten Weise mit Proteinen interagieren.
Gewinnung reaktiver Fullerene aus Ruß durch exohedrale Derivatisierung
Authors: Yamada Michio , Akasaka Takeshi , Nagase Shigeru
Published: April 2018

Die bemerkenswerte Allotropie von Kohlenstoff liefert zahlreiche topologisch mögliche Käfigstrukturen von molekularem Kohlenstoff. Dazu gehören auch die sogenannten endohedralen Metallofullerene, bei denen ein Metallatom im Käfig eingeschlossen ist. Stabile und lösliche leere Fullerene und endohedrale Metallofullerene in reiner Form sind in makroskopischen Mengen durch Erzeugung im Kohlenstofflichtbogen oder andere physikalische Prozesse mit anschließender Extraktion und chromatographischer Trennung verfügbar. Jedoch bleiben viele andere, nicht identifizierte Fulleren‐Spezies, die in ihrer reinen Form offenbar reaktiv und unlöslich sind, im Ruß zurück. Solche “fehlenden” Spezies müssen extrem kleine HOMO‐LUMO‐Aufspaltungen aufweisen und könnten unkonventionelle Käfigstrukturen zeigen. Jüngste Fortschritte in diesem Bereich haben gezeigt, dass sich reaktive Fullerene unter Verwendung einer exohedralen Derivatisierung gewinnen lassen, durch die die reaktiven Kohlenstoffkäfige stabilisiert werden können. Dieses Konzept bietet ein Mittel zur Produktion von makroskopischen Mengen unkonventioneller Fullerene.
Spectral Imaging and Archival Data in Analysing Madonna of the Rabbit Paintings by Manet and Titian
Authors: Striova Jana , Ruberto Chiara , Barucci Marco , Blažek Jan , Kunzelman Diane , Dal Fovo Alice , Pampaloni Enrico , Fontana Raffaella
Published: April 2018

A concise insight into the outputs provided by the latest prototype of visible‐near infrared (Vis‐NIR) multispectral scanner (National Research Council‐National Institute of Optics, CNR‐INO, Italy) is presented. The analytical data acquired on an oil painting Madonna of the Rabbit by É. Manet are described. In this work, the Vis‐NIR was complemented with X‐ray fluorescence (XRF) mapping for the chemical and spatial characterization of several pigments. The spatially registered Vis‐NIR data facilitated their processing by spectral correlation mapping (SCM) and artificial neural network (ANN) algorithm, respectively, for pigment mapping and improved visibility of pentimenti and of underdrawing style. The data provided several key elements for the comparison with a homonymous original work by Titian studied within the ARCHive LABoratory (ARCHLAB) transnational access project.
Wasserbildung unter dünnen Silika‐Filmen: Echtzeitbeobachtung einer chemischen Reaktion in einem physikalisch eingegrenzten Raum
Authors: Prieto Mauricio J. , Klemm Hagen W. , Xiong Feng , Gottlob Daniel M. , Menzel Dietrich , Schmidt Thomas , Freund Hans‐Joachim
Published: April 2018

Mit niederenergetischer Elektronenmikroskopie und lokaler Fotoelektronenspektroskopie wurde die Bildung von Wasser aus absorbierten O und H2 auf einer Ru(0001)‐Oberfläche untersucht, die mit einer glasartigen SiO2‐Bilage (BL) bedeckt war, und mit der gleichen Reaktion auf der reinen Ru(0001)‐Oberfläche verglichen. In beiden Fällen tritt eine fortschreitende Reaktionsfront auf. Der Grund hierfür kann mit der Anforderung zusammenhängen, dass die O‐Adatome Platz freigeben müssen, damit weiterer H2 dissoziativ adsorbiert. Wir finden scheinbare Aktivierungsenergien (
) für die Frontbewegung von 0.59 eV ohne Deckschicht und 0.27 eV mit Deckschicht. Wir schlagen vor, dass bei der SiO2‐BL‐bedeckten Ru(0001)‐Oberfläche die geringere Aktivierungsenergie aber höhere Reaktionstemperatur durch eine Änderung des geschwindigkeitsbestimmenden Schritts verursacht wird. Weitere mögliche Auswirkungen der Deckschicht werden diskutiert. Unsere Resultate ergeben die ersten Werte für
im eingegrenzten Raum (“confinement”).
Fluor‐NMR‐Spektroskopie rekalibriert
Authors: Rosenau Carl Philipp , Jelier Benson J. , Gossert Alvar D. , Togni Antonio
Published: April 2018

Fluorchemie nimmt eine zentrale Rolle bei der Entdeckung chemischer Reaktionen, in der Wirkstoffentwicklung und in der Chemischen Biologie ein. NMR‐Spektroskopie, die wohl meistbenutzte und wichtigste analytische Methode für fluorierte Verbindungen, weist weitverbreitete Missstände auf, die durch inkonsistentes Referenzieren chemischer Verschiebungen zustande kommen und Abweichungen von über 1 ppm verursachen können. In dieser Zuschrift beschreiben wir neuartige, eindeutige Belege, die zeigen, wie es – unbeabsichtigt – zur weitverbreiteten Streuung von 19F‐NMR‐chemischen‐Verschiebungen gekommen ist. Dies betrifft sowohl die Konzipierung der Spektrometer als auch das gegenwärtige Unified Scale System, das typischerweise als Grundlage für die Kalibrierung von heteronuklearen NMR‐Spektren dient. Wir zeigen, dass internes Referenzieren als robuste, pragmatische und reproduzierbare Methode die Abweichung chemischer Verschiebungen, die an mehreren verschiedenen Instituten gemessen wurden, auf weniger als 30 ppb minimiert. Schließlich wird eine umfassende Tabelle mit entsprechend kalibrierten Referenzverbindungen zur Verfügung gestellt, die es Nutzern ermöglicht, 19F‐NMR‐Spektren künftig korrekt zu kalibrieren.
Wrapping Nanocellulose Nets around Graphene Oxide Sheets
Authors: Xiong Rui , Kim Ho Shin , Zhang Lijuan , Korolovych Volodymyr F. , Zhang Shuaidi , Yingling Yaroslava G. , Tsukruk Vladimir V.
Published: April 2018

Constructing advanced functional nanomaterials with pre‐designed organized morphologies from low‐dimension synthetic and biological components is challenging. Herein, we report an efficient and universal amphiphilicity‐driven assembly strategy to construct “hairy” flexible hybrid nanosheets with a 1D cellulose nanofibers (CNFs) net conformally wrapped around 2D graphene oxide (GO) monolayers. This interface‐driven bio‐synthetic assembly is facilitated by tailoring the surface chemistry of flexible GO sheets, resulting in individual sheets tightly surrounded by dense conformal nanocellulose network. The mechanical stability of the products far exceeds the compressive instability limits of both individual components. Additionally, the CNF network significantly enhances the wetting ability of initial hydrophobic reduced GO nanosheets, allowing fast water transport combined with high filtration efficiency.
Von einer Helix zu einem kleinen Ring: Metadynamik‐inspirierte, selektive Liganden für αvβ6‐Integrin
Authors: Di Leva Francesco Saverio , Tomassi Stefano , Di Maro Salvatore , Reichart Florian , Notni Johannes , Dangi Abha , Marelli Udaya Kiran , Brancaccio Diego , Merlino Francesco , Wester Hans‐Jürgen , Novellino Ettore , Kessler Horst , Marinelli Luciana
Published: April 2018

Das RGD‐erkennende Integrin αvβ6 trat in jüngster Zeit als vielbeachtete Zielstruktur für die Diagnostik und Therapie von Krebserkrankungen in Erscheinung. Infolgedessen besteht derzeit ein dringender Bedarf an niedermolekularen Liganden für diesen Rezeptor. Ein auf Metadynamik beruhender Ansatz ermöglichte die erfolgreiche Konvertierung eines helikalen Nonapeptids in ein zyklisches Pentapeptid (6) mit bemerkenswerter Affinität und Spezifität für αvβ6‐Integrin. Die Gründe hierfür konnten mittels NMR‐ und Docking‐Untersuchungen aufgeklärt werden und bilden einen Ausgangspunkt für die zielgerichtete Konzeption neuer αvβ6‐spezifischer Peptide oder sogar Peptidomimetika. Des Weiteren wurde die Möglichkeit einer medizinischen Anwendung von 6 mittels PET‐Bildgebungsexperimenten im lebenden Organismus veranschaulicht.
Divergent Coupling of Anilines and Enones by Integration of C−H Activation and Transfer Hydrogenation
Authors: Zhou Xukai , Xia Jintao , Zheng Guangfan , Kong Lingheng , Li Xingwei
Published: April 2018

Cp*RhIII/IrIII complexes are known to play important roles in both C−H activation and transfer hydrogenation (TH). However, these two areas evolved separately. They have been integrated in redox‐ and chemodivergent coupling reactions of N‐pyridylanilines with enones. The iridium‐catalyzed coupling with enones leads to the efficient synthesis of tetrahydroquinolines through TH from iPrOH. Counterintuitively, iPrOH does not serve as the sole hydride source, and the major reaction pathway involves disproportionation of a dihydroquinoline intermediate, followed by the convergent and iterative reduction of quinolinium species.
Polar Fluorooxoborate, NaB4O6F: A Promising Material for Ionic Conduction and Nonlinear Optics
Authors: Zhang Zhizhong , Wang Ying , Zhang Bingbing , Yang Zhihua , Pan Shilie
Published: April 2018

The search of new borates with improved functional properties has attracted considerable attention. Herein, a new polar fluorooxoborate, NaB4O6F (NBF) was prepared by high‐temperature solid‐state reaction. NBF belongs to the AB4O6F family (A=alkali metal or ammonium), a series of compounds that undergoes significant cation‐dependent structural changes. NBF is of particular interest owing to the special cation position. Temperature‐dependent ionic conductivity measurements show that NBF is a solid ionic conductor, and it has the lowest active energy of 32.5 kJ mol−1 of fluorooxoborates. NBF also shows a second‐harmonic generation (SHG) response of 0.9×KH2PO4 and 0.2×β‐BaB2O4, at 1064 and 532 nm, respectively, and it has a short UV cutoff edge below 180 nm. Based on bond valence (BV) concepts, symmetry analysis, and the first principles calculation, the unique [B4O6F]∞ layer can be regarded as the “multifunctional unit”, which is responsible for the observed properties of NBF.
Bottom‐up Construction of π‐Extended Arenes by a Palladium‐Catalyzed Annulative Dimerization of o‐Iodobiaryl Compounds
Authors: Zhu Chendan , Wang Di , Wang Dingyi , Zhao Yue , Sun Wei‐Yin , Shi Zhuangzhi
Published: April 2018

A straightforward method was developed for construction of aromatic compounds with a triphenylene core. The method involves Pd‐catalyzed annulative dimerization of o‐iodobiaryl compounds by double C−I and C−H bond cleavage steps. Simple reaction conditions are needed, requiring neither a ligand nor an oxidant, and the reaction tolerates a wide range of coupling partners without compromising efficiency or scalability. Significantly, the tetrachloro‐substituted synthon, 1,6,11‐trichloro‐4‐(4‐chlorophenyl)triphenylene, can be generated and used to prepare a series of fully fused, small graphene nanoribbons by a late‐stage arylation with arylboronic acids and a subsequent Scholl reaction. The synthetic strategy enables bottom‐up access to extended π‐systems in a controlled manner.
Engineering Proteins at Interfaces: From Complementary Characterization to Material Surfaces with Designed Functions
Authors: Morsbach Svenja , Gonella Grazia , Mailänder Volker , Wegner Seraphine , Wu Si , Weidner Tobias , Berger Rüdiger , Koynov Kaloian , Vollmer Doris , Encinas Noemí , Kuan Seah Ling , Bereau Tristan , Kremer Kurt , Weil Tanja , Bonn Mischa , Butt Hans‐Jürgen , Landfester Katharina
Published: April 2018

Once materials come into contact with a biological fluid containing proteins, proteins are generally—whether desired or not—attracted by the material's surface and adsorb onto it. The aim of this Review is to give an overview of the most commonly used characterization methods employed to gain a better understanding of the adsorption processes on either planar or curved surfaces. We continue to illustrate the benefit of combining different methods to different surface geometries of the material. The thus obtained insight ideally paves the way for engineering functional materials that interact with proteins in a predetermined manner.
Salvaging Reactive Fullerenes from Soot by Exohedral Derivatization
Authors: Yamada Michio , Akasaka Takeshi , Nagase Shigeru
Published: April 2018

The awesome allotropy of carbon yields innumerable topologically possible cage structures of molecular carbon. This field is also related to endohedral metallofullerenes constructed by metal‐atom encapsulation. Stable and soluble empty fullerenes and endohedral metallofullerenes are available in pure form in macroscopic amounts from carbon arc production or other physical processes followed by extraction and subsequent chromatographic separation. However, many other unidentified fullerene species, which must be reactive and insoluble in their pristine forms, remain in soot. These “missing” species must have extremely small HOMO–LUMO gaps and may have unconventional cage structures. Recent progress in this field has demonstrated that reactive fullerenes can be salvaged by exohedral derivatization, which can stabilize the reactive carbon cages. This concept provides a means of preparing macroscopic amounts of unconventional fullerenes as their derivatives.
Water Formation under Silica Thin Films: Real‐Time Observation of a Chemical Reaction in a Physically Confined Space
Authors: Prieto Mauricio J. , Klemm Hagen W. , Xiong Feng , Gottlob Daniel M. , Menzel Dietrich , Schmidt Thomas , Freund Hans‐Joachim
Published: April 2018

Using low‐energy electron microscopy and local photoelectron spectroscopy, water formation from adsorbed O and H2 on a Ru(0001) surface covered with a vitreous SiO2 bilayer (BL) was investigated and compared to the same reaction on bare Ru(0001). In both cases the reaction is characterized by moving reaction fronts. The reason for this might be related to the requirement of site release by O adatoms for further H2‐dissociative adsorption. Apparent activation energies (
) are found for the front motion of 0.59 eV without cover and 0.27 eV under cover. We suggest that the smaller activation energy but higher reaction temperature for the reaction on the SiO2 BL covered Ru(0001) surface is due to a change of the rate‐determining step. Other possible effects of the cover are discussed. Our results give the first values for
in confined space.
Macrotheranostic Probe with Disease‐Activated Near‐Infrared Fluorescence, Photoacoustic, and Photothermal Signals for Imaging‐Guided Therapy
Authors: Zhen Xu , Zhang Jianjian , Huang Jiaguo , Xie Chen , Miao Qingqing , Pu Kanyi
Published: April 2018

Theranostics provides opportunities for precision cancer therapy. However, theranostic probes that simultaneously turn on their diagnostic signal and pharmacological action only in respond to a targeted biomarker have been less exploited. We herein report the synthesis of a macrotheranostic probe that specifically activates its near‐infrared fluorescence (NIRF), photoacoustic (PA), and photothermal signals in the presence of a cancer‐overexpressed enzyme for imaging‐guided cancer therapy. Superior to the small‐molecule counterpart probe, the macrotheranostic probe has ideal biodistribution and renal clearance, permitting passive targeting of tumors, in situ activation of multimodal signals, and effective photothermal ablation. Our study thus provides a macromolecular approach towards activatable multimodal phototheranostics.
Mono‐ and binuclear nickel catalysts for 1‐hexene polymerization
Authors: Dechal Abbas , Khoshsefat Mostafa , Ahmadjo Saeid , Mortazavi Seyed Mohammad Mahdi , Zohuri Gholam Hossein , Abedini Hossein
Published: April 2018

Polymerization of 1‐hexene was carried out using a mononuclear (MN) catalyst and two binuclear (BN1 and BN2) α‐diimine Ni‐based catalysts synthesized under controlled conditions. Ethylaluminium sesquichloride (EASC) was used as an efficient activator under various polymerization conditions. The highly active BN2 catalyst (2372 g poly(1‐hexene) (PH) mmol−1 cat) in comparison to BN1 (920 g PH mmol−1 cat) and the MN catalyst (819 g PH mmol−1 cat) resulted in the highest viscosity‐average molecular weight (Mv) of polymer. Moreover, the molecular weight distribution (MWD) of PH obtained using BN2/EASC was slightly broader than those obtained using BN1 and MN (2.46 for BN2 versus 2.30 and 1.96 for BN1 and MN, respectively). These results, along with the highest extent of chain walking for BN2, were attributed to steric, nuclearity and electronic effects of the catalyst structures which could control the catalyst behaviour. Differential scanning calorimetry showed that the glass transition temperatures of polymers were in the range − 58 to −81 °C, and broad melting peaks below and above 0 °C were also observed. In addition, longer α‐olefins (1‐octene and 1‐decene) were polymerized and characterized, for which higher yield, conversion and molecular weight were observed with a narrower MWD. The polymerization parameters such as polymerization time and polymerization temperature showed a significant influence on the productivity of the catalysts and Mv of samples.
Sucrose chelated auto combustion synthesis of BiFeO3 nanoparticles: Magnetically recoverable catalyst for the one‐pot synthesis of polyhydroquinoline
Authors: Singh Harminder , Garg Nidhi , Arora Priya , Rajput Jaspreet Kaur , Jigyasa
Published: April 2018

Sucrose chelated Bismuth ferrite (BiFeO3) nanoparticles as a novel heterogeneous catalyst was synthesized by an auto combustion route. Different calcination temperatures (150 °C, 450 °C, 550 °C, 650 °C, 750 °C and 850 °C) have been employed to obtain single phased BiFeO3 nanoparticles. The perovskite structure formation and disappearance of organic phase (sucrose) was obtained by Fourier transform infrared spectroscopy (FT‐IR). Phase determination and structural characterization was carried out by powder X‐ray diffraction (XRD). The magnetic properties were analyzed by vibrating sample magnetometer (VSM) whereas surface area/pore volume was obtained by Brunauer–Emmett–Teller (BET). Transmission electron microscope (TEM) analyzed the particles size and morphology. Thermal stability was investigated by thermogravimetric analysis (TGA) and determination of constituent elements was carried out by X‐ray Photo‐Electron Spectroscopy (XPS). Raman spectroscopy confirmed the perovskite structure of the synthesized materials. The BiFeO3 nanoparticles so obtained were employed as heterogeneous catalyst for the synthesis of polyhydroquinoline derivatives. All the polyhydroquinoline derivatives were characterized by Fourier transform infrared spectroscopy (FT‐IR) and Nuclear magnetic resonance spectroscopy (1H NMR). For the very first time ever we have used BiFeO3 as a recyclable magnetic nanocatalyst in the one‐pot four component cyclization reaction of benzaldehyde, ethylacetoacetate/methylacetoacetate, dimedone/cyclohexane‐1,3‐dione, and ammonium acetate for the synthesis of polyhydroquinoline derivatives without solvent under refluxing conditions to provide excellent yields of products. BiFeO3 nanocatalyst (without any functionalization/surface coatings) shows easy magnetic separation, recyclability, reusability along with excellent yield of polyhydroquinoline derivatives in an economic and benign way.
Triel–hydride triel bond between ZX3 (Z = B and Al; X = H and Me) and THMe3 (T = Si, Ge and Sn)
Authors: Zhang Jingru , Wei Yuanxin , Li Wenzuo , Cheng Jianbo , Li Qingzhong
Published: April 2018

Complexes between THMe3 (T = Si, Ge and Sn) and ZX3 (Z = B and Al; X = H and Me) have been characterized using MP2/aug‐cc‐pVTZ calculations. These complexes are chiefly stabilized by a triel–hydride triel bond with the T–H bond pointing to the π‐hole on the triel atom. The triel–hydride interaction is mainly attributed to the charge transfer from the T–H bond orbital to the empty p orbital of the triel atom. These complexes are very stable with a large interaction energy (>10 kcal mol−1) excluding THMe3···BMe3 (T = Si and Ge), indicating that the sp2‐hydridized triel atom has a strong affinity for the T–H bond. The formation of THMe3···BH3 results in proton transfer, characterized by conversion of orbital interaction and large charge transfer (ca 0.5e). The large deformation is primarily responsible for the abnormally greater interaction energy in THMe3···BH3 (>30 kcal mol−1) than in the AlH3 analogue. Methyl substitution on the triel atom weakens the triel–hydride interaction and causes a larger interaction energy in THMe3···AlMe3 with respect to its BMe3 counterpart. Most of these interactions possess characteristics of covalent bonds. Polarization makes a contribution to the stability of most complexes nearly equivalent to the electrostatic term.
Preparation and characterization of Cu (II) supported on poly(8‐hydroxyquinoline‐p‐styrene sulphonate) and its application as catalyst for the synthesis of hexahydroquinolines
Authors: Khazaei Ardeshir , Tavasoli Mahsa , Jamshidi Vahid , Ghalil Fatemeh Gohari , Moosavi‐Zare Ahmad Reza
Published: April 2018

Cu (II) supported on poly(8‐hydroxyquinoline‐p‐styrenesulfonate) (Cu (II)@PHQSS) was prepared and fully characterized by the different techniques including fourier transform infrared spectroscopy (FT‐IR), 1H NMR, 13C NMR, thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG), differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersive X‐ray analysis (EDS). Afterward, the Cu (II)@PHQSS as nanostructured catalyst was used as catalyst for the synthesis of hexahydroquinolines.
CO2 desorption tests of blended monoethanolamine–diethanolamine solutions to discover novel energy efficient solvents
Authors: Shi Huancong , Zheng Linna , Huang Min , Zuo Yuanhui , Li Mingyue , Jiang Linhua , Idem Raphael , Tontiwachwuthikul Paitoon
Published: April 2018

The CO2 desorption tests were conducted at 363–378 K for 5.0 mol/L blended monoethanolamine (MEA)‐diethanolamine (DEA) solutions to develop the energy efficient solvents with high CO2 production and low energy consumptions. These desorption tests were performed with a recirculation process for various preloaded, 5 mol/L (4.5 + 0.5 to 0.5 + 4.5) MEA‐DEA solutions to find out the optimized solvents with minimum heat duty. Therefore, 1–4 mol/L and 0.5–0.45 mol/L MEA‐DEA solvents have larger CO2 production (nCO2) and lower heat duties (
) than 5 mol/L DEA under similar operation conditions. They have lower heat duty (510 and 538 kJ/mol) than DEA (572 kJ/mol) due to increased CO2 desorption rates, despite 10% higher heat input (QTotal) than DEA. Moreover, the critical points were studied as research focus of amine regeneration curves, along with reaction energy calculation. Finally, secondary amines blending minor MEA (<20%) as promotor turned out to be an alternative approach of solvents improvement with low energy requirement.
Study of the effect of the temperature of caustic tower operation on red oil formation in olefin units
Authors: Hu Xun , Gholizadeh Mortaza , Samudi Mohsen
Published: April 2018

This study aims to investigate the effect of caustic tower operation temperature on red oil formation and clogging of the tower. For this aim, the caustic tower of Tabriz Petrochemical Plant was used. The operation temperature of the tower was varied from 38 up to 50 °C, and the amount and composition of the red oil formed were investigated. Our results indicate that the amount and composition of the red oil formed inside the tower were different at varied temperatures. At 42–45 °C, minimum amount of the red oil formed, whereas at other temperatures, the products with 2 phases (oil phase on the top and aqueous phase in the bottom) were produced. The red oil formed is mainly alkanes, alkenes, dienes, and also aldehydes. They are produced from the cracking of naphtha, which some could undergo polymerisation reactions in the caustic tower, resulting in the formation of red oil. This formation of the red oil could decrease the efficiency of absorption column due to the problem of chocking. In addition, the red oil will accumulate on internal surfaces of equipment and the bottom of the column, leading to fouling and eventually plugging. The analysis showed that the polymerisation reactions produce heavy alkanes, aromatics, and cyclic compounds. Via optimisation of caustic tower operation temperature, the red oil formation could be drastically decreased.
Interaction of two differently sized bubbles in a viscous liquid
Authors: Zhang Yang , Chen Ke , You Yunxiang , Ren Wei
Published: April 2018

Interaction of two in‐line bubbles with different size in a viscous liquid is studied using volume‐of‐fluid method. Simulations are performed on initially spherical bubbles starting from rest. The influences of size ratio 0.5 ≤ R ≥ 1 and initial distance ratio 1.7 ≤ S ≥ 3 are investigated with fixed Eötvös number Eo = 50, Galilei number Ga = 100, density ratio η = 1,000, and viscosity ratio λ = 100. Two arrangement patterns are considered, the small‐big arrangement (SBA) and big‐small arrangement (BSA). Two distinct evolution regimes are defined: coalescence and penetration. The bubble‐bubble interaction is intensified by increasing R and decreasing S, promoting the possibility of coalescence. Penetration is more prone to occur in BSA than in SBA, and it is absent in BSA when R ≤ 0.625 regardless of S. The ascending velocity of the leading bubble (LB) is nearly independent of size ratio, initial distance ratio, and arrangement pattern, since the motion of the LB is little influenced by the trailing bubble (TB). Meanwhile, the ascending velocity of the TB increases with increasing R and decreasing S. The LB usually plays a dominant role in the interaction, especially in BSA.
Effects of TiO2nanoparticles on the photodegradation of poly(lactic acid)
Authors: Luo Yanbing , Cao Yuzhen , Guo Gang
Published: April 2018

Photodegradable poly(lactic acid) (PLA)/titanium dioxide (TiO2) nanocomposites could be utilized as an eco‐friendly material. The photocatalytic degradation was investigated under accelerating artificial ultraviolet irradiation conditions for the period up to 100 days according to GB/T16422.3/ISO 4892.4. The change of surface color, gloss loss, morphology, weight loss, intrinsic viscosity, chemical structure, mechanical properties at different irradiation times were verified via solid reflection spectrophotometer, scanning electron microscopy, Ubbelohde viscometer, Fourier transform infrared spectrometer, and tensile test. The structural change accompanied by the degradation of the irradiated samples clearly showed that the photodegradation of PLA/TiO2nanocomposites process was via a bulk erosion mechanism. The photodegradability of PLA/TiO2samples was higher than that of pure PLA and benefitted a lot from a good dispersion of TiO2nanoparticles. The present study suggests that the photodegradation of PLA could be controlled by loading dispersed g‐TiO2nanoparticles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46509.