bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Segregation of Ternary Alloys: Effect of the Interaction between Solute Elements
Authors: Zhao Meng , Brouwer Johannes C. , Sloof Willem G. , Böttger Amarante J.
Published: February 2020

Ternary alloys have been developed for a wide range of applications and surface segregation of ternary alloys has a decisive impact on their performance. Different from binary alloys, in which surface energy is usually the dominant factor, the interaction between solute elements has a noticeable effect on the surface segregation behavior of ternary alloys. As a practical example, Pd‐based ternary alloys have been proposed as promising candidates for hydrogen separation membranes due to their excellent permeability and selectivity. In the present work, surface segregation of Pd‐Cu‐Ag and Pd‐Cu‐Mo ternary alloys in both vacuum and hydrogen atmosphere is investigated. X‐ray photoelectron spectroscopy and low energy ion scattering spectroscopy analyses reveal that the segregation trend of the outermost atomic layer is not always the same as that of the near‐surface region. A thermodynamic model is developed to describe the surface segregation of ternary alloys. The results of the model are in good qualitative agreement with experimental results. Furthermore, calculations for other ternary alloy systems confirm that the model provides a simple but universal method for surface segregation in ternary alloys. The results can also be considered as basic guidelines to design novel ternary alloys for various applications.
Ultrathin WS2‐on‐Glass Photonic Crystal for Self‐Resonant Exciton‐Polaritonics
Authors: Zhang Xingwang , Zhang Xiaojie , Huang Wenzhuo , Wu Kedi , Zhao Mengqiang , Charlie Johnson A. T. , Tongay Sefaattin , Cubukcu Ertugrul
Published: February 2020

Room temperature stable excitons in layered two‐dimensional (2D) transition metal dichalcogenides (TMDs) offer a unique route for engineering light and matter interactions. Due to the strong optical dispersion near the excitonic transitions, a high refractive index arises in these ultrathin semiconductors.[1,2] Utilizing this behavior, strongly confined Fano type optical resonances in an ultrathin (i.e., ≈12 nm) tungsten disulfide (WS2) photonic crystal (PhC) directly fabricated on a TMD‐on‐glass platform are reported. In this approach, Fano‐type WS2 photonic resonances strongly couple to the WS2 excitonic dispersion engender self‐resonant exciton‐polaritons with an out‐of‐plane optical confinement exceeding that provided by surface plasmon polaritons in the visible. The large spatial light‐matter overlap endowed by this unique monolithic self‐coupling scheme is utilized for steering of enhanced 2D WSe2 excitonic photoluminescence in a truly TMD integrated system. It is envisioned that the strong light matter interaction on the TMD‐on‐glass platform will unfold the prospects of ultrathin exciton‐polaritonic resonators.
Planar Terahertz Photonics Mediated by Liquid Crystal Polymers
Authors: Shen Zhi‐Xiong , Tang Ming‐Jie , Chen Peng , Zhou Sheng‐Hang , Ge Shi‐Jun , Duan Wei , Wei Ting , Liang Xiao , Hu Wei , Lu Yan‐Qing
Published: February 2020

Terahertz (THz) band is expected to satisfy the ever‐increasing demand for high‐capacity wireless data transfer. Multifunctional photonic devices with compactness and low loss are highly pursued for future THz communications. Here, a strategy for planar THz photonics is proposed that enables free wavefront manipulation with submillimeter thin liquid crystal polymer (LCP) films. Such elements work on the spatial geometric phase modulation, which is accomplished by preprogramming the axis orientations of LCP. The LCP monomers follow the guidance of local photoalignment agent and are further polymerized under UV exposure at the existence of a doped photo‐initializer. Thanks to the high resolution and excellent flexibility of the photopatterning technique, THz elements with versatile functions can be realized. As examples, waveplates, polarization gratings, and lenses, which are suitable for the polarization control, beam deflecting, focusing, or collimating, are demonstrated. Due to the intrinsic flexibility of LCP films, an f‐tunable lens enabled by mechanically induced deformation is exhibited. Specific mode generators for vortices and Bessel beams are also presented, which can function as separate channels for the mode division multiplexing in THz communications. This work provides a robust platform for fabricating integrated, low‐loss, and tunable THz elements suitable for the advanced THz apparatuses.
Transient Supramolecular Hydrogels Formed by Aging‐Induced Seeded Self‐Assembly of Molecular Hydrogelators
Authors: Wang Yiming , Piskorz Tomasz K. , Lovrak Matija , Mendes Eduardo , Guo Xuhong , Eelkema Rienk , van Esch Jan H.
Published: February 2020

Here, transient supramolecular hydrogels that are formed through simple aging‐induced seeded self‐assembly of molecular gelators are reported. In the involved molecular self‐assembly system, multicomponent gelators are formed from a mixture of precursor molecules and, typically, can spontaneously self‐assemble into thermodynamically more stable hydrogels through a multilevel self‐sorting process. In the present work, it is surprisingly found that one of the precursor molecules is capable of self‐assembling into nano‐sized aggregates upon a gentle aging treatment. Importantly, these tiny aggregates can serve as seeds to force the self‐assembly of gelators along a kinetically controlled pathway, leading to transient hydrogels that eventually spontaneously convert into thermodynamically more stable hydrogels over time. Such an aging‐induced seeded self‐assembly process is not only a new route toward synthetic out‐of‐equilibrium supramolecular systems, but also suggests the necessity of reporting the age of self‐assembling building block solutions in other self‐assembly systems.
Smart Hydrogels for the Augmentation of Bone Regeneration by Endogenous Mesenchymal Progenitor Cell Recruitment
Authors: Lienemann Philipp S. , Vallmajo‐Martin Queralt , Papageorgiou Panagiota , Blache Ulrich , Metzger Stéphanie , Kiveliö Anna‐Sofia , Milleret Vincent , Sala Ana , Hoehnel Sylke , Roch Aline , Reuten Raphael , Koch Manuel , Naveiras Olaia , Weber Franz E. , Weber Wilfried , Lutolf Matthias P. , Ehrbar Martin
Published: February 2020

The treatment of bone defects with recombinant bone morphogenetic protein‐2 (BMP‐2) requires high doses precluding broad clinical application. Here, a bioengineering approach is presented that strongly improves low‐dose BMP‐2‐based bone regeneration by mobilizing healing‐associated mesenchymal progenitor cells (MPCs). Smart synthetic hydrogels are used to trap and study endogenous MPCs trafficking to bone defects. Hydrogel‐trapped and prospectively isolated MPCs differentiate into multiple lineages in vitro and form bone in vivo. In vitro screenings reveal that platelet‐derived growth factor BB (PDGF‐BB) strongly recruits prospective MPCs making it a promising candidate for the engineering of hydrogels that enrich endogenous MPCs in vivo. However, PDGF‐BB inhibits BMP‐2‐mediated osteogenesis both in vitro and in vivo. In contrast, smart two‐way dynamic release hydrogels with fast‐release of PDGF‐BB and sustained delivery of BMP‐2 beneficially promote the healing of bone defects. Collectively, it is shown that modulating the dynamics of endogenous progenitor cells in vivo by smart synthetic hydrogels significantly improves bone healing and holds great potential for other advanced applications in regenerative medicine.
Quantifying Charge‐Carrier Mobilities and Recombination Rates in Metal Halide Perovskites from Time‐Resolved Microwave Photoconductivity Measurements
Authors: Savenije Tom J. , Guo Dengyang , Caselli Valentina M. , Hutter Eline M.
Published: February 2020

The unprecedented rise in the power conversion efficiency of solar cells based on metal halide perovskites (MHPs) has led to enormous research effort to understand their photophysical properties. The progress made in understanding the mobility and recombination of photogenerated charge carriers from nanosecond to microsecond time scales, monitored using electrodeless transient photoconductivity techniques, is reviewed. In addition, a kinetic model to obtain rate constants from transient data recorded using a wide range of laser intensities is presented. For various MHPs the temperature dependence of the mobilities and recombination rates are evaluated. Furthermore, it is shown how these rate constants can be used to predict the upper limit for the open‐circuit voltage Voc of the corresponding device. Finally, the photophysical properties of MHPs that are not yet fully understood are explored, and recommendations for future research directions are made.
Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells
Authors: Si Haonan , Zhang Suicai , Ma Shuangfei , Xiong Zhaozhao , Kausar Ammarah , Liao Qingliang , Zhang Zheng , Sattar Abdul , Kang Zhuo , Zhang Yue
Published: February 2020

Metal halide perovskite materials, benefiting from a combination of outstanding optoelectronic properties and low‐cost solution‐preparation processes, show tremendous potential for optoelectronics and photovoltaics. However, the nanoscale inhomogeneities of the electronic properties of perovskite materials cause a number of difficulties, such as recombination, stability, and hysteresis, all of which seriously restrict device performance. Scanning probe microscopy, as a high‐resolution imaging technique, has been widely used to connect local properties and micro‐area morphologies to overall device performance. Conductive atomic force microscopy (C‐AFM) can realize a real‐space visualization of topography coupled with optoelectronic properties on a microscopic scale and thereby is uniquely suited to probe the local effects of perovskite materials and devices. The fundamental principles, alternative operation modes, and development of C‐AFM are comprehensively reviewed, and applications in perovskite solar cells (PSCs) for electronic transport behavior, ion migration and hysteresis, ferroelectric polarization, and facet orientation investigation are discussed. A comprehensive understanding and summary of up‐to‐date applications in PSCs is beneficial to further fully exploit the potential of such an emerging technique, so as to provide a novel and effective approach for perovskite materials analysis.
Atomic‐Resolution Imaging of Halide Perovskites Using Electron Microscopy
Authors: Song Kepeng , Liu Lingmei , Zhang Daliang , Hautzinger Matthew P. , Jin Song , Han Yu
Published: February 2020

Atomic‐resolution imaging of halide perovskites (HPs) using transmission electron microscopy (TEM) is challenging because of the sensitivity of their structures to the electron beam. In this article, recent achievements in this area are reviewed, covering both all‐inorganic and organic–inorganic hybrid HPs, with an emphasis on the specific imaging conditions that have proven to be effective in avoiding electron beam‐induced structural damage. The discussion focusses on the total electron dose that HPs can bear before being damaged and the effects of different imaging modes, accelerating voltages, and temperatures. The crucial role of a direct‐detection electron‐counting camera in reducing the required electron dose is outlined, which is indispensable for imaging extremely sensitive organic–inorganic hybrid perovskites. In addition to reviewing published works, the results of initial attempts to perform atomic‐resolution elemental mapping for an all‐inorganic HP and image a hybrid HP using scanning TEM are introduced. The preparation of a TEM specimen from macroscopic crystals or devices of HPs, which is very important for practical applications but has not yet received attention, is also discussed. This article aims to provide guidance on the acquisition of atomic‐resolution TEM images of HPs and inspire the development of more imaging technologies for sensitive materials.
The relationship between light intensity, cannabis yields, and profitability
Authors: Eaves James , Eaves Stephen , Morphy Chad , Murray Chris
Published: February 2020

The purpose of this study was to analyze the relationship between light intensity, cannabis (Cannabis sativa L.) yields, and profitability. We also look for evidence that spectrum differences across broad‐spectrum horticulture lights and general‐purpose LEDs affect the relationship between yield and light intensity. Finally, we discuss the financial return of increasing light intensity in order to increase yields. We found that yields increase linearly with light intensity up to at least 1500 µmol m–2 s–1, which is at least twice the intensity that is most commonly used by cannabis growers. That relationship did not appear to be influenced by spectrum quality differences among the lamps included in the study. Finally, for all the intensity ranges that we considered, the value of the gain in yields from increasing light intensity far exceeded the cost of using more electricity.
The effect of liquid viscosity and modeling of mass transfer in gas–liquid slug flow in a rectangular microchannel
Authors: Yao Chaoqun , Zhao Yuchao , Zheng Jia , Zhang Qi , Chen Guangwen
Published: February 2020

Both chemical (by adding 0.05 M NaOH) and physical absorption of CO2 into aqueous glycerol solutions with viscosity up to 45.6 mPa·s in a microchannel are investigated. The concentration distribution pattern, absorption time, and mass transfer coefficient are analyzed and discussed. A new concentration distribution pattern is observed with the lowest concentration locating at the channel center. It is shown for the first time that presents a positive relationship with liquid viscosity, which is explained by the essential role of the mass exchange between the liquid film and bulk liquid slug. This mass exchange may lead to a rise in k
L when increasing the liquid viscosity under some cases in chemical absorption. A mass transfer model is successfully applied to predict the bubble size evolution in physical absorption. The model also shows about 10–46% of the mass transfer contribution from liquid films before saturation.
Expanding the genotypic spectrum of Jalili syndrome: Novel CNNM4 variants and uniparental isodisomy in a north American patient cohort
Authors: Prasov Lev , Ullah Ehsan , Turriff Amy E. , Warner Blake M. , Conley Julie , Mark Paul R. , Hufnagel Robert B. , Huryn Laryssa A.
Published: February 2020

Jalili syndrome is a rare multisystem disorder with the most prominent features consisting of cone‐rod dystrophy and amelogenesis imperfecta. Few cases have been reported in the Americas. Here we describe a case series of patients with Jalili syndrome examined at the National Eye Institute's Ophthalmic Genetics clinic between 2016 and 2018. Three unrelated sporadic cases were systematically evaluated for ocular phenotype and determined to have cone‐rod dystrophy with bull's eye maculopathy, photophobia, and nystagmus. All patients had amelogenesis imperfecta. Two of these patients had Guatemalan ancestry and the same novel homozygous CNNM4 variant (p.Arg236Trp c.706C > T) without evidence of consanguinity. This variant met likely pathogenic criteria by the American College of Medical Genetics guidelines. An additional patient had a homozygous deleterious variant in CNNM4 (c.279delC p.Phe93Leufs*31), which resulted from paternal uniparental isodisomy for chromosome 2p22‐2q37. This individual had additional syndromic features including developmental delay and spastic diplegia, likely related to mutations at other loci. Our work highlights the genotypic variability of Jalili syndrome and expands the genotypic spectrum of this condition by describing the first series of patients seen in the United States.
Maternal weight affects placental DNA methylation of genes involved in metabolic pathways in the common marmoset monkey (Callithrix jacchus)
Authors: Narapareddy Laren , Wildman Derek E. , Armstrong Don L. , Weckle Amy , Bell Aleeca F. , Patil Crystal L. , Tardif Suzette D. , Ross Corinna N. , Rutherford Julienne N.
Published: February 2020

Accumulating evidence suggests that dysregulation of placental DNA methylation (DNAm) is a mechanism linking maternal weight during pregnancy to metabolic programming outcomes. The common marmoset, Callithrix jaccus, is a platyrrhine primate species that has provided much insight into studies of the primate placenta, maternal condition, and metabolic programming, yet the relationships between maternal weight and placental DNAm are unknown. Here, we report genome‐wide DNAm from term marmoset placentas using reduced representation bisulfite sequencing. We identified 74 genes whose DNAm pattern is associated with maternal weight during gestation. These genes are predominantly involved in energy metabolism and homeostasis, including the regulation of glycolytic and lipid metabolic processes pathways.
Reagenzien für die selektive Fluormethylierung: Herausforderungen der Organofluorchemie
Authors: Reichel Marco , Karaghiosoff Konstantin
Published: February 2020

Die Einführung einer CH2F‐Gruppe in organische Moleküle ist in den letzten Jahren zweifellos zu einem sehr wichtigen Forschungsgebiet geworden. Aufgrund der vorteilhaften Eigenschaften von Organofluorverbindungen – wie ihre metabolische Stabilität – ist der Einbau der CH2F‐Gruppe als bioisosterer Ersatz für verschiedene funktionelle Gruppen eine attraktive Strategie, um z. B. neue Medikamente zu entwickeln. Darüber hinaus findet die Monofluormethyleinheit auch in der Agrochemie, in der pharmazeutischen Chemie und in der Feinchemie einen breiten Einsatz. Aufgrund des menschengemachten Klimawandels und des wachsenden Bedarfs an umweltfreundlichen industriellen Prozessen sind Alternativen zu den häufig verwendeten Fluormethylierungsmitteln auf FCKW‐ und HFBKW‐Basis (CH2FCl und CH2FBr) dringend erforderlich und im Montrealer Protokoll auch gefordert. Dies hat in letzter Zeit viele Forscher dazu veranlasst, die Entwicklung umweltfreundlicher Fluormethylierungsmittel zu entwickeln. Dieser Kurzaufsatz umfasst sowohl die klassischen als auch die neue Generation von Fluormethylierungsmitteln. Es werden Reagenzien und deren Vorläuferverbindungen diskutiert, die sowohl direkt als auch indirekt über elektrophile und nukleophile als auch radikalische Wege reagieren.
Ein Periodensystem der supramolekularen Elemente
Authors: Schmidt Hans‐Werner , Würthner Frank
Published: February 2020

Die Chemie jenseits des Moleküls basiert auf schwachen, nicht‐kovalenten und damit reversiblen Wechselwirkungen. Als Folge dieser schwachen Bindungen kann eine strukturelle Organisation durch Faltung und Selbstorganisation üblicherweise nur für größere Moleküle stattfinden, die multiple Kontaktstellen aufweisen. Heute lassen sich solche “Supramoleküle” synthetisieren und ihre Faltungen in gewünschte Konformationen vorhersagen. Durch das Schaffen nicht‐natürlicher Einheiten, die aus molekularen Bausteinen mit definierten Sekundärstrukturen bestehen, kann eine neue Ebene der Chemie realisiert werden. Hier definieren wir diese Bausteine als “supramolekulare Elemente”. Wir erwarten, dass eine zunehmende Ausrichtung der Forschung auf große Moleküle Konstruktionsprinzipien aufdecken wird, die von wiederkehrenden Motiven beherrscht werden, welche die Strukturbildung durch Faltung und Selbstorganisation steuern. Diese Prinzipien sind mit der Organisation von Atomen im Periodensystem der Elemente vergleichbar. Daher können diese Organisationsprinzipien auch zur Entwicklung eines Periodensystems der supramolekularen Elemente führen.
Excimer‐ und Exciplex‐Bildung in durch aurophile Wechselwirkungen präkonditionierten Gold(I)‐ Komplexen
Authors: Schmidbaur Hubert , Raubenheimer Helgard G.
Published: February 2020

Excimere und Exciplexe sind definiert als Aggregate von Atomen oder Molekülen A/A′, in denen es nur in angeregten Zuständen [A2]* und [AA′]* zu interatomaren/‐molekularen Bindungen kommt. Ihre Bildung wurde weithin bekannt durch ihre Bedeutung in Gasphasen‐Lasertechnologien. Jüngste Untersuchungen in der Goldchemie haben der Excimer‐ und Exciplex‐Chemie ein neues Gebiet eröffnet, das hauptsächlich durch die Aggregation von Gold(I)‐Verbindungen (AuI(5d10)) über aurophile Kontakte bedingt wird. In den zugehörigen Excimeren entstehen Au–Au‐Bindungen mit Bindungsenergien und ‐abständen, die denen im Grundzustand von Au0(5d106s1)‐ und AuII(5d9)‐Verbindungen entsprechen. Der aktuelle Kenntnisstand über Excimere und Exciplexe in der Goldchemie wird hier vorgestellt, vorwiegend an einfachen Beispielen wie der Assoziation von [Au(CN)2]−‐Anionen in Festkörpern und in Lösung. Die Excimer‐Bildung führt zu einem breiten Spektrum an photophysikalischen Effekten, deren Relaxationsdynamik in einigen Fällen kürzlich aufgeklärt wurde. Excimere sind aktuell auch von großer Bedeutung auf dem Gebiet der “photoredox binuclear gold catalysis”.
Continuous and Segmented Semiconducting Fiber‐like Nanostructures with Spatially Selective Functionalization by Living Crystallization‐Driven Self‐Assembly
Authors: Tao Daliao , Wang Zhiqin , Huang Xiaoyu , Tian Mingwei , Lu Guolin , Manners Ian , Winnik Mitchell A. , Feng Chun
Published: February 2020

Fiber‐like π‐conjugated nanostructures are important components of flexible organic electronic and optoelectronic devices. To broaden the range of potential applications, one needs to control not only the length of these nanostructures, but the introduction of diverse functionality with spatially selective control. Here we report the synthesis of a crystalline‐coil block copolymer of oligo(p‐phenylenevinylene)‐b‐poly(2‐vinylpyridine) (OPV5‐b‐P2VP44), in which the basicity and coordinating/chelating ability of the P2VP segment provide a landscape for the incorporation of a variety of functional inorganic NPs. Through a self‐seeding strategy, we were able to prepare monodisperse fiber‐like micelles of OPV5‐b‐P2VP44 with lengths ranging from 50 to 800 nm. Significantly, the exposed two ends of OPV core of these fiber‐like micelles remained active toward further epitaxial deposition of OPV5‐b‐PNIPAM49 and OPV5‐b‐P2VP44 to generate uniform A‐B‐A and B‐A‐B‐A‐B segmented block comicelles with tunable lengths for each block. The P2VP domains in these (co‐)micelles can be selectively decorated with inorganic and polymeric nanoparticles as well as metal oxide coatings, to afford hybrid fiber‐like nanostructures. This work provides a versatile strategy toward the fabrication of narrow length dispersity continuous and segmented π‐conjugated OPV‐containing fiber‐like micelles with the capacity to be decorated in a spatially selective way with varying functionalities.
Reagents for Selective Fluoromethylation: A Challenge in Organofluorine Chemistry
Authors: Reichel Marco , Karaghiosoff Konstantin
Published: February 2020

The introduction of a monofluoromethyl moiety has undoubtedly become a very important area of research in recent years. Owing to the beneficial properties of organofluorine compounds, such as their metabolic stability, the incorporation of the CH2F group as a bioisosteric substitute for various functional groups is an attractive strategy for the discovery of new pharmaceuticals. Furthermore, the monofluoromethyl unit is also widely used in agrochemistry, in pharmaceutical chemistry, and in fine chemicals. The problems associated with climate change and the growing need for environmentally friendly industrial processes mean that alternatives to the frequently used CFC and HFBC fluoromethylating agents (CH2FCl and CH2FBr) are urgently needed and also required by the Montreal Protocol. This has recently prompted many researchers to develop alternative fluoromethylation agents. This Minireview summarizes both the classical and new generation of fluoromethylating agents. Reagents that act via electrophilic, nucleophilic, and radical pathways are discussed, in addition to their precursors.
Electrophysiological Characterization of Transport Across Outer‐Membrane Channels from Gram‐Negative Bacteria in Presence of Lipopolysaccharides
Authors: Wang Jiajun , Terrasse Rémi , Bafna Jayesh Arun , Benier Lorraine , Winterhalter Mathias
Published: February 2020

Multi‐drug resistance in Gram‐negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we present an approach using fusion of native outer membrane vesicles (OMVs) into a planar lipid bilayer, allowing characterization of membrane protein channels in their native environment. Two major membrane channels from E. coli, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion surprisingly revealed only single or few channel activities. The asymmetry of the OMVs translates after fusion into the lipid membrane with the lipopolysaccharides (LPS) dominantly present at the side of OMV addition. Compared to the conventional reconstitution method, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution and significantly lower permeation. We suggest using outer membrane vesicles for functional and structural studies of membrane channels in the native membrane.
A Periodic System of Supramolecular Elements
Authors: Schmidt Hans‐Werner , Würthner Frank
Published: February 2020

Chemistry “beyond the molecule” is based on weak, noncovalent, and reversible interactions. As a consequence of these bonds being weak, structural organization by folding and self‐assembly can only be fully exploited with larger molecules that can provide multiple binding sites. Such “supramolecules” can now be synthesized and their folding into desired conformations predicted. A new level of chemistry can now be realized through the creation of non‐natural entities composed of molecular building blocks with defined secondary structures. Herein we define these building blocks as “supramolecular elements”. We anticipate that further research on such large molecules will reveal construction principles dictated by recurring motifs that govern structure formation through folding and self‐assembly. These principles are comparable to the organization of atoms in the Periodic Table of Chemical Elements and may lead to the establishment of a Periodic System of Supramolecular Elements.
Excimer and Exciplex Formation in Gold(I) Complexes Preconditioned by Aurophilic Interactions
Authors: Schmidbaur Hubert , Raubenheimer Helgard G.
Published: February 2020

Excimers and exciplexes are defined as assemblies of atoms or molecules A/A′ where interatomic/intermolecular bonding appears only in excited states such as [A2]* (for excimers) and [AA′]* (for exciplexes). Their formation has become widely known because of their role in gas‐phase laser technologies, but their significance in general chemistry terms has been given little attention. Recent investigations in gold chemistry have opened up a new field of excimer and exciplex chemistry that relies largely on the preorganization of gold(I) compounds (electronic configuration AuI(5d10)) through aurophilic contacts. In the corresponding excimers, a new type of Au⋅⋅⋅Au bonding arises, with bond energies and lengths approaching those of ground‐state Au−Au bonds between metal atoms in the Au0(5d106s1) and AuII(5d9) configurations. Excimer formation gives rise to a broad range of photophysical effects, for which some of the relaxation dynamics have recently been clarified. Excimers have also been shown to play an important role in photoredox binuclear gold catalysis.
Design and characterization of Fe3O4/GO/Au‐Ag nanocomposite as an efficient catalyst for the green synthesis of spirooxindole‐dihydropyridines
Authors: Kavyani Sara , Baharfar Robabeh
Published: February 2020

A novel magnetic nanocomposite of Au‐Ag nanoparticles anchored on Fe3O4/graphene oxide spheres (Fe3O4/GO/Au‐Ag) was successfully fabricated by the layer‐by‐layer assembly technique. The prepared Fe3O4/GO/Au‐Ag was fully characterized by Fourier‐transform infrared (FT‐IR) spectroscopy, X‐ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), field‐emission scanning electron microscopy (FE‐SEM), energy‐dispersive x‐ray spectroscopy (EDS), transmission electron microscopy (TEM), and Raman spectroscopy. This nanocomposite showed unique catalytic performance for the synthesis of Spiro[indoline‐3,5′‐pyrido[2,3‐d:6,5‐d’]dipyrimidine]‐pentaone derivatives by the three‐component condensation reaction of isatins, barbituric acids and 6‐amino uracil at room temperature and in aqueous media. The significant advantages of this protocol include highly stable, easily separable and reusable catalyst, simple operation, environmental friendliness and excellent yields.
Transition Metal–organic Coordination Polymers Containing 6‐(1H‐imidazol‐1‐yl)‐2(1H)‐Pyridinone: Synthesis, Structure and Fluorescent Sensing for Enoxacin
Authors: Li Shanshan , Zhou Xin , Xu Qiwei , Liu Dongmei , Cui Ruifang , Li Xia
Published: February 2020

Three metal–organic coordination polymers, [M(2,6‐bip)2] (M = Zn (1), Ni (2)) and [Cu (tfbdc)(2,6‐bipH)2]•2H2O (3), were obtained with the similar solvothermal reaction systems of bivalent transition metal salt, 6‐(1H‐imidazol‐1‐yl)‐2(1H)‐pyridinone (2,6‐bipH) and 2,3,5,6‐tetrafluoroterephthalic acid (H2tfbdc). The three coordination polymers show different framework features, namely 3D (1), 2D (2) and 1D (3) structures, which are resulted from different single‐metal ion “node” and “linker” coordination modes. The [ZnO2N2] tetrahedron in 1 and [NiO2N4] octahedron in 2 as a node, is formed from Zn sp3 and Ni d2sp3 hybrid orbits, respectively, while the linker, 2,6‐bip, adopts the μ2:η1η1η0 in 1 and μ2:η1η1η1 in 2 coordination modes. PLATON calculation suggests that 1 possesses the micropore structure with a pore volume of 14.2%. In 3, the [CuO2N2] parallelogram as a node is derived from Cu dsp3 hybrid orbital, while the linkers of 2,6‐bipH and tfbdc adopt the μ1:η1η0η0 and μ1:η1η0/μ1:η1η0 coordination modes, respectively. Intriguingly, Zn(d10)‐centre coordination polymer 1 shows strong blue emission, which are derived from the π* → π transition of the 2,6‐bipH ligand. Moreover, 1 exhibits high stability and strong luminescence in both water and ethanol. At this point, the performance of 1 is studied as a chemical sensor for detecting fluoroquinolones drug. The results show that 1 can detect enoxacin in ethanol solution with a low detection limit of 3.61 × 10−5 M. The luminescent sensing mechanisms were investigated from experimental methods and theoretical calculation in detail as well.
Evaluation of thermoplastic polyolefin materials for the hard shed of composite insulators
Authors: Shi Jia , Dong Hao , Quan Yiwu , Chen Chao , Yan Shanzhi
Published: February 2020

This article explores the possibility of using polyolefin materials for composite insulator sheds. The transfer component (silicone oil or erucamide) is added into a polyolefin material to improve its hydrophobic properties. Results show that the silicone oil‐modified polyolefin material (polyolefin‐S) exhibited an obvious hydrophobicity transfer property. When the equivalent salt deposit density and nonsoluble deposit density are 0.1 and 0.5 mg/cm2, respectively, the static contact angle increases from 75° to 87° as the silicone oil transfer time increases from 24 to 96 hr. Meanwhile, polyolefin‐S exhibits high mechanical strength, hardness, volume resistivity, and surface resistivity values of 21.4 MPa, 62.6 HD, 1.7 × 1015 Ω m and 1.2 × 1016 Ω, respectively. Moreover, polyolefin‐S shows excellent tracking and erosion resistance of 4.5 kV level in the inclined plane test. The results verify that the polyolefin material is a promising candidate material for the hard shed of composite insulators.
Incorporation of Pseudo‐complementary Bases 2,6‐Diaminopurine and 2‐Thiouracil into Serinol Nucleic Acid (SNA) to Promote SNA/RNA Hybridization
Authors: Kamiya Yukiko , Sato Fuminori , Murayama Keiji , Kodama Atsuji , Uchiyama Susumu , Asanuma Hiroyuki
Published: February 2020

Serinol nucleic acid (SNA) is a promising candidate for nucleic acid‐based molecular probes and drugs due to its high affinity for RNA. Our previous work revealed that incorporation of 2,6‐diaminpurine (D), which can form three hydrogen bonds with uracil, into SNA increases the melting temperature of SNA‐RNA duplexes. However, D incorporation into short self‐complementary regions of SNA promoted self‐dimerization and hindered hybridization with RNA. Here we synthesized a SNA monomer of 2‐thiouracil (sU), which was expected to inhibit base pairing with D by steric hindrance between sulfur and the amino group. To prepare the SNA containing D and sU in high yield, we customized the protecting groups on D and sU monomers that can be readily deprotected under acidic conditions. Incorporation of D and sU into SNA facilitated stable duplex formation with target RNA by suppressing the self‐hybridization of SNA and increasing the stability of the heteroduplex of SNA and its complementary RNA. Our results have important implications for the development of SNA‐based probes and nucleic acid drugs.
Asymmetric Hydroformylation Using a Rhodium Catalyst Encapsulated in a Chiral Capsule
Authors: Jongkind Lukas J. , Reek Joost N. H.
Published: February 2020

Supramolecular capsules can be used to change the activity and selectivity of a catalyst through the influence of the second coordination sphere, reminiscent of how enzymes control the selectivity of their processes. In enzymes, this approach is used to also control the enantioselectivity of reactions in which the active catalytic site is often not chiral but the second coordination sphere is. We are interested in the possibility to generate a chiral second coordination sphere around an otherwise achiral transition metal complex for asymmetric catalysis. In this paper we show that the ligand template approach can be used to generate a chiral second coordination sphere around a rhodium complex, which is used in asymmetric hydroformylation.
Tungsten(VI) Complex of N‐Fused Porphyrin Absorbing Near‐Infrared Light beyond 1000 nm
Authors: Yamamoto Takaaki , Abraham Jibin Alex , Mori Shigeki , Toganoh Motoki , Shimizu Soji , Ishida Masatoshi , Furuta Hiroyuki
Published: February 2020

Incorporating tungsten into the N3 core of a N‐fused porphyrin (NFP; 1) affords high‐valent tungsten(VI)‐NFP complexes, WClO2‐1 and 21‐chlorinated WClO2‐3. The X‐ray structure of WClO2‐1 reveals a distorted octahedral geometry with sitting atop metal coordination. The absorption spectrum of WClO2‐1 displays bathochromically shifted Q‐like bands beyond 1000 nm, indicating an inherently narrow HOMO‐LUMO energy gap. DFT calculations show that the degeneracy of the LUMO and LUMO+1 pair of 1 is significantly resolved by the tungsten(VI) coordination. Conclusively, magnetic circular dichroism (MCD) spectroscopy and cyclic voltammetry provide a rationale for the narrow HOMO‐LUMO energy gap in the “16‐electron” d0 tungsten(VI)‐NFP complexes.
Machine learning to predict biomass sorghum yields under future climate scenarios
Authors: Huntington Tyler , Cui Xinguang , Mishra Umakant , Scown Corinne D.
Published: February 2020

Crop yield modeling is critical in the design of national strategies for agricultural production, particularly in the context of a changing climate. Forecasting yields of bioenergy crops at fine spatial resolutions can help to evaluate near‐term and long‐term pathways for scaling up bio‐based fuel and chemical production, and for understanding the impacts of abiotic stressors such as severe droughts and temperature extremes on potential biomass supply. We used a large dataset of 28,364 Sorghum bicolor yield samples (uniquely identified by county and year of observation), environmental variables, and multiple approaches to analyze historical trends in sorghum productivity across the USA. We selected the most accurate machine learning approach (a variation of the random forest approach) to predict future trends in sorghum yields under four greenhouse gas (GHG) emission scenarios and two irrigation regimes. We identified irrigation practices, vapor pressure deficit, and time (a proxy for technological improvement) as the most important predictors of sorghum productivity. Our results showed a decreasing trend of sorghum yields over future years (on average 2.7% from 2018 to 2099), with greater decline under a high GHG emissions scenario (3.8%) and in the absence of irrigation (4.6%). Geographically, we observed the steepest predicted declines in the Great Lakes (8.2%), Upper Midwest (7.5%), and Heartland (6.7%) regions. Our study demonstrates the use of machine learning to identify environmental controllers of sorghum biomass yield and predict yields with reasonable accuracy. These results can inform the development of more realistic biomass supply projections for bioenergy if sorghum production is scaled up. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd
Metal–Organic Frameworks for Photodynamic Therapy: Emerging Synergistic Cancer Therapy
Authors: Song Yucong , Wang Lei , Xie Zhigang
Published: February 2020

Photodynamic therapy (PDT) conducted by photosensitizers producing cytotoxic reactive oxygen species (ROS) under light irradiation is widely used in cancer treatment. A great number of photoactive nanoscale metal–organic frameworks (NMOFs) have been prepared for PDT. With the development of biomedicine and nanotechnology, many synergistic cancer therapies have emerged. In this mini‐review, an overview on the latest progress in the application of NMOFs in PDT is provided, with emphasis on the recent emergence of some synergistic therapies.
Process‐wide control and automation of an integrated continuous manufacturing platform for antibodies
Authors: Feidl Fabian , Vogg Sebastian , Wolf Moritz , Podobnik Matevz , Ruggeri Caterina , Ulmer Nicole , Wälchli Ruben , Souquet Jonathan , Broly Hervé , Butté Alessandro , Morbidelli Massimo
Published: February 2020

Integrated continuous manufacturing is entering the biopharmaceutical industry. The main drivers range from improved economics, manufacturing flexibility, and more consistent product quality. However, studies on fully integrated production platforms have been limited due to the higher degree of system complexity, limited process information, disturbance, and drift sensitivity, as well as difficulties in digital process integration. In this study, we present an automated end‐to‐end integrated process consisting of a perfusion bioreactor, CaptureSMB, virus inactivation (VI), and two polishing steps to produce an antibody from an instable cell line. A supervisory control and data acquisition (SCADA) system was developed, which digitally integrates unit operations and analyzers, collects and centrally stores all process data, and allows process‐wide monitoring and control. The integrated system consisting of bioreactor and capture step was operated initially for 4 days, after which the full end‐to‐end integrated run with no interruption lasted for 10 days. In response to decreasing cell‐specific productivity, the supervisory control adjusted the loading duration of the capture step to obtain high capacity utilization without yield loss and constant antibody quantity for subsequent operations. Moreover, the SCADA system coordinated VI neutralization and discharge to enable constant loading conditions on the polishing unit. Lastly, the polishing was sufficiently robust to cope with significantly increased aggregate levels induced on purpose during virus inactivation. It is demonstrated that despite significant process disturbances and drifts, a robust process design and the supervisory control enabled constant (optimum) process performance and consistent product quality.
Limited life cycle and cost assessment for the bioconversion of lignin‐derived aromatics into adipic acid
Authors: van Duuren Jozef B. J. H. , de Wild Paul J. , Starck Sören , Bradtmöller Christian , Selzer Mirjam , Mehlmann Kerstin , Schneider Roland , Kohlstedt Michael , Poblete‐Castro Ignacio , Stolzenberger Jessica , Barton Nadja , Fritz Michel , Scholl Stephan , Venus Joachim , Wittmann Christoph
Published: February 2020

Lignin is an abundant and heterogeneous waste byproduct of the cellulosic industry, which has the potential of being transformed into valuable biochemicals via microbial fermentation. In this study, we applied a fast‐pyrolysis process using softwood lignin resulting in a two‐phase bio‐oil containing monomeric and oligomeric aromatics without syringol. We demonstrated that an additional hydrodeoxygenation step within the process leads to an enhanced thermochemical conversion of guaiacol into catechol and phenol. After steam bath distillation, Pseudomonas putida KT2440‐BN6 achieved a percent yield of cis, cis‐muconic acid of up to 95 mol% from catechol derived from the aqueous phase. We next established a downstream process for purifying cis, cis‐muconic acid (39.9 g/L) produced in a 42.5 L fermenter using glucose and benzoate as carbon substrates. On the basis of the obtained values for each unit operation of the empirical processes, we next performed a limited life cycle and cost analysis of an integrated biotechnological and chemical process for producing adipic acid and then compared it with the conventional petrochemical route. The simulated scenarios estimate that by attaining a mixture of catechol, phenol, cresol, and guaiacol (1:0.34:0.18:0, mol ratio), a titer of 62.5 (g/L) cis, cis‐muconic acid in the bioreactor, and a controlled cooling of pyrolysis gases to concentrate monomeric aromatics in the aqueous phase, the bio‐based route results in a reduction of CO2‐eq emission by 58% and energy demand by 23% with a contribution margin for the aqueous phase of up to 88.05 euro/ton. We conclude that the bio‐based production of adipic acid from softwood lignins brings environmental benefits over the petrochemical procedure and is cost‐effective at an industrial scale. Further research is essential to achieve the proposed cis, cis‐muconic acid yield from true lignin‐derived aromatics using whole‐cell biocatalysts.
Synthesis of Porous Carbon‐coated Cobalt Catalyst through Pyrolyzing Metal–Organic Framework and their Bifunctional OER/ORR Catalytic Activity for Zn‐Air Rechargeable Batteries
Authors: Kuk Yunseung , Ahmed Sheraz , Sun Ho‐Jung , Shim Joongpyo , Park Gyungse
Published: February 2020

A metal–organic framework (MOF) was synthesized using 4,4′‐stilbenedicarboxylic acid (H2SDA) in dimethylformamide (DMF). Carbon‐coated Co (C@Co) catalysts were prepared by the direct calcination of Co3(SDA)3(DMF)2 MOF crystals at various temperatures. The highest surface area of the C@Co catalyst is obtained at 600 °C which can further be increased by the ball mill operation. The X‐ray photon spectroscopy and X‐ray diffraction analysis proved the formation of metallic Co in the carbon matrix at temperatures over 500 °C, while Co3O4 formation was observed at 500 °C. Furthermore, the graphitic properties of the Co particles were analyzed by Raman spectroscopy. The durability of the carbon‐coated Co catalysts derived from MOFs (C@Co catalysts) was analyzed by the cycle test (charge/discharge at 20 mA/cm2 per 2 h) and was retained over 350 h. These catalysts showed remarkable stability for both ORR (oxygen reduction reaction) and OER (oxygen evolution reaction), comparable to that of Co3O4 and Co metal powder in alkaline solution.
Determination of 15 Biomarkers of Endocrine Disrupting Chemicals in Human Saliva by Gas Chromatography–Mass Spectrometry
Authors: Vu Thi Hoang Van , Lim Hyun‐Hee , Shin Ho‐Sang
Published: February 2020

A sensitive method was developed to simultaneously determine 15 biomarkers of endocrine disrupting chemicals (EDCs) in human saliva using dispersive liquid–liquid microextraction (DLLME) and gas chromatography–mass spectrometry. This study also confirmed that the phthalate diesters were converted by glucuronidase/aryl sulfatase to their respective primary metabolites –mono‐esters, but not to the secondary metabolites. The amount of 100 μL β‐glucuronidase/aryl sulfatase hydrolyzed about 95% of the phthalate diesters (500 μg/L) within 3 h. The problems of hydrolysis of phthalate diesters by β‐glucuronidase/aryl sulfatase are discussed. Ethyl acetate and acetonitrile were selected as extraction and disperser solvents in DLLME, and then the extracts were subjected to derivatization with N‐methyl‐N‐(tert‐bultyl dimethyl silyl) trifluoroacetamide directly without concentration after extraction. After optimizing the required conditions, good linearity of analytes was achieved. The limit of detection (LOD) and the limit of quantification (LOQ) were in the ranges of 0.015–3.0 μg/L and 0.05–10 μg/L, respectively.
Impact of self‐perception of aging on mortality of older patients in oncology
Authors: Schroyen Sarah , Letenneur Luc , Missotten Pierre , Jérusalem Guy , Adam Stéphane
Published: February 2020

Objective

Several studies show that self‐perception of aging (SPA) is a significant predictor of mental and physical health. In this study, we analyze the effect of SPA on mortality in the specific context of geriatric oncology.

Methods

The sample constituted of 140 individuals aged 65 years and older suffering from a recent nonmetastatic cancer (breast, lung, gynecological, or hematological), followed up to 6 years. We used Cox proportional hazards model to assess the effect of SPA at baseline on mortality. It was adjusted for age, gender, educational and cognitive level, oncological information (the site and kind of cancer), number of comorbidities, and physical and mental health at baseline.

Results

Patients were aged 73 years at diagnosis and were more often women (85.7%). Individuals with more negative SPA were 3.62 times more likely to die than those with a more positive SPA, with control of gender, age, education and cognitive level, mental and physical health, the category (breast, lung, gynecological, or hematological), and kind (initial or recurrence) of cancer.

Conclusions

These findings suggest that SPA influence the mortality of older people in the particular context of oncology. Therefore, the need to change our attitudes toward aging and older people implied indirectly by these results is discussed.
Upregulation of hsa_circ_0007874 suppresses the progression of ovarian cancer by regulating the miR‐760/SOCS3 pathway
Authors: Li Li , Yu Poling , Zhang Ping , Wu Huanmei , Chen Qizhen , Li Shuangdi , Wang Yanqiu
Published: February 2020

Ovarian cancer (OVA) is a fatal and common malignancy in women worldwide. Circular RNAs (circRNAs) consist of a family of circular endogenous RNAs generated by selective splicing, and they are involved in many diseases. Previous studies reported that hsa_circ_0007874 is aberrantly expressed in cancer and functions in tumorigenesis. While the hsa_circ_0007874 role in OVA is unclear. Here, we detected the hsa_circ_0007874 expression in OVA cell lines using Rt‐qPCR. Hsa_circ_0007874 subcellular localization was confirmed by fluorescence in situ hybridization. The relationship between hsa_circ_0007874, microRNAs (miRNAs), and relative protein levels was assessed using the luciferase reporter assays. Results verified that hsa_circ_0007874 is downregulated in OVA cell lines. hsa_circ_0007874 overexpression decreased the OVA cell migration and proliferation in vitro and in vivo. Bioinformatics and luciferase reporter assays confirmed that miR‐760 and SOCS3 are the downstream targets of hsa_circ_0007874. Downregulation of SOCS3 or miR‐760 overexpression restored the migration and proliferation ability of SKOV3 or A2780 cells overexpressing hsa_circ_0007874. Downregulation of SOCS3 restored the proliferation and migration in miR‐760 knockdown SKOV3 and A2780 cells. In summary, the data suggest that hsa_circ_0007874 acts as a tumor suppressor by regulating the miR‐760/SOCS3 axis, highlighting its potential as an effective therapeutic target for OVA.