bluuebunny/crossref_metadata_2025 huggingface dataset:
Early season vigor in peanuts is dependent on leaf area responses to temperature
Authors: Virk Gurpreet , Pilon Cristiane , Snider John L. , Tubbs R. Scott
Published: March 2020

Whole‐crop growth at early season in peanuts (Arachis hypogaea L.) can be influenced by genotype, management, and environmental conditions such as soil and air temperatures. To determine the effect of different planting conditions on peanut growth and vigor in the early season, modern peanut cultivars were planted in two growing seasons on 17 April, 10 May, and 5 June in 2017 and 25 April, 14 May, and 11 June in 2018 season, targeted to generate differences in temperature during early growth. Field measurements included emergence assessments and destructive harvest at 21 and 35 days after planting to quantify plant density, height, leaf area, and dry matter accumulation. Additionally, crop growth indices were calculated. Results showed that planting date and cultivar significantly affected plant growth parameters and derived growth indices. Planting in June resulted in greater growth parameters, crop growth rate, and leaf area index compared to April and May for both seasons. However, net assimilation rate was highest for May in 2017 and for June in 2018. Comparing cultivars, Georgia‐06G and TifNV‐high O/L were more vigorous than Georgia‐14N. Average soil and air temperatures were the highest with June planting and produced more vigorous seedling growth and greater crop growth rates than planting in April and May. Furthermore, our results suggest that the differences in the early season crop growth of modern peanut cultivars were more strongly and closely associated with leaf area development rather than specific leaf activity, that is, net assimilation rate of the canopy.
Kristalle in Minutenschnelle: Sofortige Mikrokristallisation verschiedenster Varianten der CYP102A1‐(P450BM3)‐Hämdomäne
Authors: Stanfield Joshua Kyle , Omura Keita , Matsumoto Ayaka , Kasai Chie , Sugimoto Hiroshi , Shiro Yoshitsugu , Watanabe Yoshihito , Shoji Osami
Published: March 2020

Die Kristallisation der Hämdomäne von CYP102A1 (P450BM3) kann nach Modifizierung eine Herausforderung sein. Dennoch sind solche Kristallstrukturen unentbehrlich für die wirksame strukturbezogene Entwicklung von P450BM3 als Biokatalysator. Es wurde gezeigt, dass das Abietanditerpenderivat N‐Abietoyl‐l‐tryptophan (AbiATrp) ein hervorragender Kristallisationsbeschleuniger ist. Die Nutzung von Kristallen der P450BM3‐Hämdomäne mit AbiATrp als Impfkristalle ermöglichte die rasche Mikrokristallisation bei der naszierende Kristalle innerhalb von Sekunden nach Impfung erschienen. Hierdurch wurde eine Auswahl an Kristallen der P450BM3‐Hämdomäne erhalten, die bisher nicht kristallisierbare Täuschmoleküle, diverse künstliche Metalloporphyrine, welche verschiedenartige Liganden binden, sowie zusätzlich stark getaggte Hämdomänevarianten enthalten (37 zusätzliche Aminosäuren). Manche der Strukturen könnten als Modellverbindungen verschiedener Stadien des katalytischen Zyklus von P450BM3 genutzt werden.
Spatiotemporal Control of CRISPR/Cas9 Function in Cells and Zebrafish using Light‐Activated Guide RNA
Authors: Zhou Wenyuan , Brown Wes , Bardhan Anirban , Delaney Michael , Ilk Amber S. , Rauen Randy R. , Kahn Shoeb I. , Tsang Michael , Deiters Alexander
Published: March 2020

We developed a new method for the conditional regulation of CRISPR/Cas9 activity in mammalian cells and zebrafish embryos using photochemically activated, caged guide RNAs (gRNAs). Caged gRNAs are generated by substituting four nucleobases evenly distributed throughout the 5′‐protospacer region with caged nucleobases during synthesis. Caging confers complete suppression of gRNA:dsDNA‐target hybridization and rapid restoration of CRISPR/Cas9 function upon optical activation. This tool offers simplicity and complete programmability in design, high spatiotemporal specificity in cells and zebrafish embryos, excellent off‐to‐on switching, and stability by preserving the ability to form Cas9:gRNA ribonucleoprotein complexes. Caged gRNAs are novel tools for the conditional control of gene editing, thereby enabling the investigation of spatiotemporally complex physiological events by obtaining a better understanding of dynamic gene regulation.
An Fe2+‐ and α‐Ketoglutarate‐Dependent Halogenase Acts on Nucleotide Substrates
Authors: Zhao Chunhua , Yan Shan , Li Qin , Zhu Hucheng , Zhong Zhiyu , Ye Ying , Deng Zixin , Zhang Yonghui
Published: March 2020

While halogenated nucleosides are used as common anticancer and antiviral drugs, naturally occurring halogenated nucleosides are rare. Adechlorin (ade) is a 2′‐chloro nucleoside natural product first identified from Actinomadura sp. ATCC 39365. However, the installation of chlorine in the ade biosynthetic pathway remains elusive. Reported herein is a Fe2+‐α‐ketoglutarate halogenase AdeV that can install a chlorine atom at the C2′ position of 2′‐deoxyadenosine monophosphate to afford 2′‐chloro‐2′‐deoxyadenosine monophosphate. Furthermore, 2′,3′‐dideoxyadenosine‐5′‐monophosphate and 2′‐deoxyinosine‐5′‐monophosphate can also be converted, albeit 20‐fold and 2‐fold, respectively, less efficiently relative to the conversion of 2′‐deoxyadenosine monophosphate. AdeV represents the first example of a Fe2+‐α‐ketoglutarate‐dependent halogenase that converts nucleotides into chlorinated analogues.
Silicon‐Free SuFEx Reactions of Sulfonimidoyl Fluorides: Scope, Enantioselectivity, and Mechanism
Authors: Liang Dong‐Dong , Streefkerk Dieuwertje E. , Jordaan Daan , Wagemakers Jorden , Baggerman Jacob , Zuilhof Han
Published: March 2020

SuFEx reactions, in which an S−F moiety reacts with a silyl‐protected phenol, have been developed as powerful click reactions. In the current paper we open up the potential of SuFEx reactions as enantioselective reactions, analyze the role of Si and outline the mechanism of this reaction. As a result, fast, high‐yielding, “Si‐free” and enantiospecific SuFEx reactions of sulfonimidoyl fluorides have been developed, and their mechanism shown, by both experimental and theoretical methods, to yield chiral products.
Two‐Photon Absorption Enhancement by the Inclusion of a Tropone Ring in Distorted Nanographene Ribbons
Authors: Castro‐Fernández Silvia , Cruz Carlos M. , Mariz Inês F. A. , Márquez Irene R. , Jiménez Vicente G. , Palomino‐Ruiz Lucía , Cuerva Juan M. , Maçôas Ermelinda , Campaña Araceli G.
Published: March 2020

A new family of distorted ribbon‐shaped nanographenes was designed, synthesized, and their optical and electrochemical properties were evaluated, pointing out an unprecedented correlation between their structural characteristics and the two‐photon absorption (TPA) responses and electrochemical band gaps. Three nanographene ribbons have been prepared: a seven‐membered‐ring‐containing nanographene presenting a tropone moiety at the edge, its full‐carbon analogue, and a purely hexagonal one. We have found that the TPA cross‐sections and the electrochemical band gaps of the seven‐membered‐ring‐containing compounds are higher and lower, respectively, than those of the fully hexagonal polycyclic aromatic hydrocarbon (PAH). Interestingly, the inclusion of additional curvature has a positive effect in terms of non‐linear optical properties of those ribbons.
Phenanthrene‐Fused‐Quinoxaline as a Key Building Block for Highly Efficient and Stable Sensitizers in Copper‐Electrolyte‐Based Dye‐Sensitized Solar Cells
Authors: Jiang Huiyun , Ren Yameng , Zhang Weiwei , Wu Yongzhen , Socie Etienne Christophe , Carlsen Brian Irving , Moser Jacques‐E. , Tian He , Zakeeruddin Shaik Mohammed , Zhu Wei‐Hong , Grätzel Michael
Published: March 2020

Dye‐sensitized solar cells (DSSCs) based on CuII/I bipyridyl or phenanthroline complexes as redox shuttles have achieved very high open‐circuit voltages (VOC, more than 1 V). However, their short‐circuit photocurrent density (JSC) has remained modest. Increasing the JSC is expected to extend the spectral response of sensitizers to the red or NIR region while maintaining efficient electron injection in the mesoscopic TiO2 film and fast regeneration by the CuI complex. Herein, we report two new D‐A‐π‐A‐featured sensitizers termed HY63 and HY64, which employ benzothiadiazole (BT) or phenanthrene‐fused‐quinoxaline (PFQ), respectively, as the auxiliary electron‐withdrawing acceptor moiety. Despite their very similar energy levels and absorption onsets, HY64‐based DSSCs outperform their HY63 counterparts, achieving a power conversion efficiency (PCE) of 12.5 %. PFQ is superior to BT in reducing charge recombination resulting in the near‐quantitative collection of photogenerated charge carriers.
Stimuli‐Responsive Particle‐Based Amphiphiles as Active Colloids Prepared by Anisotropic Click Chemistry
Authors: Lanz Cornelia , Schlötter Moritz , Klinkenberg Nele , Besirske Patricia , Polarz Sebastian
Published: March 2020

Amphiphiles alter the energy of surfaces, but the extent of this feature is typically constant. Smart systems with amphiphilicity as a function of an external, physical trigger are desirable. As a trigger, the exposure to a magnetic field, in particular, is attractive because it is not shielded in water. Amphiphiles like surfactants are well known, but the magnetic response of molecules is typically weak. Vice‐versa, magnetic particles with strong response to magnetic triggers are fully established in nanoscience, but they are not amphiphilic. In this work colloids with Janus architecture and ultra‐small dimensions (25 nm) have been prepared by spatial control over the thiol‐yne click modification of organosilica‐magnetite core–shell nanoparticles. The amphiphilic properties of these anisotropically modified particles are proven. Finally, a pronounced and reversible change in interfacial stabilization results from the application of a weak (<1 T) magnetic field.
Designing Silicates as Deep‐UV Nonlinear Optical (NLO) Materials using Edge‐Sharing Tetrahedra
Authors: Wu Hongping , Zhang Bingbing , Yu Hongwei , Hu Zhanggui , Wang Jiyang , Wu Yicheng , Halasyamani P. Shiv
Published: March 2020

Discovering new deep‐ultraviolet (DUV) nonlinear optical (NLO) materials is currently a great challenge. The reported DUV NLO materials are almost exclusively borates or phosphates. Silicates—the largest constituent of the earth's crust—are excluded owing to their weak second harmonic generation (SHG) response. We report a silicate, Li2BaSiO4, with edge‐sharing LiO4–SiO4 tetrahedra that achieves the balance between a short UV absorption edge, below 190 nm, and a large SHG response, 2.8×KDP. The SHG intensity is the largest for silicates without second‐order Jahn–Teller cations, and exceeds that of non‐isomorphic Li2SrSiO4 by more than an order of magnitude. As such Li2BaSiO4 may be seen as a promising DUV‐UV NLO material. This research indicates that edge‐sharing tetrahedra is a new design parameter for discovering new DUV NLO materials.
Lead Mixed Oxyhalides Satisfying All Fundamental Requirements for High‐Performance Mid‐Infrared Nonlinear Optical Materials
Authors: Chen Xinglong , Jo Hongil , Ok Kang Min
Published: March 2020

To design high‐performance mid‐infrared (mid‐IR) nonlinear optical (NLO) materials, we have focused on the combination of a heavy metal lone pair cation, Pb2+ and mixed oxyhalides. A systematic investigation in PbO‐PbCl2‐PbBr2 system led us to discover the first examples of NLO lead mixed oxyhalides, namely, Pb13O6Cl4Br10, Pb13O6Cl7Br7, and Pb13O6Cl9Br5. All the reported materials have remarkably comprehensive properties including broad IR transparency (up to 14.0 μm), qualified second harmonic generation (SHG) responses (0.6–0.9×AgGaS2), wide band gaps (3.05–3.21 eV), and ease of crystal growth. Interestingly, a centimeter‐sized single crystal (2.9×1.3×0.5 cm3) of Pb13O6Cl9Br5 revealing a wide transparent range (0.384–14.0 μm) and high laser damage threshold (LDT) (14.6×AgGaS2) has been successfully grown in an open system. The study suggests that all the reported mixed oxyhalides are outstanding candidates for mid‐IR NLO materials.
Synthese von Galaktosyl‐Queuosin und Verteilung von hypermodifizierten Q‐Nukleosiden in Mausgeweben
Authors: Thumbs Peter , Ensfelder Timm T. , Hillmeier Markus , Wagner Mirko , Heiss Matthias , Scheel Constanze , Schön Alexander , Müller Markus , Michalakis Stylianos , Kellner Stefanie , Carell Thomas
Published: March 2020

Queuosin (Q) ist ein hypermodifiziertes RNA‐Nukleosid, welches in tRNAHis, tRNAAsn, tRNATyr und tRNAAsp vorkommt. Es befindet sich an der Wobble‐Position der tRNA‐Antikodonschleife und kann sowohl mit U‐ als auch mit C‐Basen interagieren, welche sich an der entsprechenden Position der passenden mRNA‐Kodons befinden. In höheren Eukaryoten, einschließlich des Menschen, wird die Q‐Base in tRNATyr und tRNAAsp aus noch unbekannten Gründen durch einen Galaktose‐ bzw. Mannoserest weiter modifiziert. Die biologische Bedeutung dieser zusätzlichen Modifikation, sowie der Stoffwechselweg, über den die Zuckermodifikation mit der Bildung und dem Einbau von Q zusammenhängt, ist unbekannt. Wir berichten hier über die erste Totalsynthese des hypermodifizierten Nukleosids Galaktosyl‐Queuosin (galQ). Unter Verwendung des von uns synthetisierten Standards konnten die absoluten Mengen der Nukleoside der Q‐Familie nicht nur in sechs verschiedenen Organen von neugeborenen und ausgewachsenen Mäusen, sondern darüber hinaus auch in menschlichen zytosolischen tRNAs bestimmt werden. Unsere Synthese erlaubt nun eine detailliertere Analyse der biologischen Funktion der Q‐Nukleosid‐Familie.
Übergangsmetallfreie oxidative Kreuzkupplung von Tetraarylboraten zu Biarylen mit organischen Oxidationsmitteln
Authors: Gerleve Carolin , Studer Armido
Published: March 2020

Leicht zugängliche Tetraarylborate reagieren in selektiven (Kreuz‐)Kupplungen durch Oxidation mit dem Bobbitt‐Salz zu symmetrischen und unsymmetrischen Biarylen. Das organische Oxoammoniumsalz kann entweder als stöchiometrisches Oxidationsmittel oder als Katalysator in Kombination mit in situ erzeugtem NO2 und molekularem Sauerstoff als terminalem Oxidans eingesetzt werden. Für ausgesuchte Fälle ist die oxidative Kupplung auch mit NO2/O2 ohne zusätzlichem Nitroxid‐basierten Co‐Katalysator möglich. Die übergangsmetallfreie katalytische oxidative Liganden‐Kreuzkupplung von Tetraarylboraten ist bisher beispiellos und die vorgestellte Methode ermöglicht den Zugang zu verschiedenen Biarylen und Heterobiarylen.
Dramatic Enhancement of Binding Affinities Between Foldamer‐Based Receptors and Anions by Intra‐Receptor π‐Stacking
Authors: Seo Sung Beom , Lee Seungwon , Jeon Hae‐Geun , Jeong Kyu‐Sung
Published: March 2020

As a synthetic model for intra‐protein interactions that reinforce binding affinities between proteins and ligands, the energetic interplay of binding and folding was investigated using foldamer‐based receptors capable of adopting helical structures. The receptors were designed to have identical hydrogen‐bonding sites for anion binding but different aryl appendages that simply provide additional π‐stacking within the helical backbones without direct interactions with the bound anions. In particular, the presence of electron‐deficient aryl appendages led to dramatic enhancements in the association constant between the receptor and chloride or nitrate ions, by up to three orders of magnitude. Extended stacking within the receptor contributes to the stabilization of the entire folding structure of complexes, thereby enhancing binding affinities.
Achieving Morphological Control over Lamellar Manganese Metal‐Organic Framework through Modulated Bi‐Phase Growth
Authors: Shen Yuxia , Shan Bohan , Mu Bin , Tongay Sefaattin
Published: March 2020

A modulated bi‐phase synthesis towards large‐scale manganese 1,4‐benzenedicarboxylate (MnBDC) MOFs with a precise control over their morphology (bulk vs. layered) is presented. Metal precursors and organic ligands are separated to reduce the kinetic reaction rates for better control over the crystallization process. Based on scanning electron microscopy (SEM), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDS), and Raman spectroscopy studies, the continuous ligand supply along with the presence of pyridine capping agent are highly effective in promoting the layer‐by‐layer growth and achieving large crystal sizes. Once layered MnBDC is stabilized, topotactic intercalation chemistry was used to demonstrate the feasibility of bromine intercalation on these layered materials. Bromine intercalation is possible between the MOFs layers for the first time. Bromine intercalation causes colossal reduction in layered MnBDC band gap while it has no observable effect on bulk MOFs.
Crystals in Minutes: Instant On‐Site Microcrystallisation of Various Flavours of the CYP102A1 (P450BM3) Haem Domain
Authors: Stanfield Joshua Kyle , Omura Keita , Matsumoto Ayaka , Kasai Chie , Sugimoto Hiroshi , Shiro Yoshitsugu , Watanabe Yoshihito , Shoji Osami
Published: March 2020

Despite CYP102A1 (P450BM3) representing one of the most extensively researched metalloenzymes, crystallisation of its haem domain upon modification can be a challenge. Crystal structures are indispensable for the efficient structure‐based design of P450BM3 as a biocatalyst. The abietane diterpenoid derivative N‐abietoyl‐l‐tryptophan (AbiATrp) is an outstanding crystallisation accelerator for the wild‐type P450BM3 haem domain, with visible crystals forming within 2 hours and diffracting to a near‐atomic resolution of 1.22 Å. Using these crystals as seeds in a cross‐microseeding approach, an assortment of P450BM3 haem domain crystal structures, containing previously uncrystallisable decoy molecules and diverse artificial metalloporphyrins binding various ligand molecules, as well as heavily tagged haem‐domain variants, could be determined. Some of the structures reported herein could be used as models of different stages of the P450BM3 catalytic cycle.
Enantioselective Synthesis of N–C Axially Chiral Compounds by Cu‐Catalyzed Atroposelective Aryl Amination
Authors: Frey Johanna , Malekafzali Alaleh , Delso Isabel , Choppin Sabine , Colobert Françoise , Wencel‐Delord Joanna
Published: March 2020

N−C axially chiral compounds have emerged recently as appealing motifs for drug design. However, the enantioselective synthesis of such molecules is still poorly developed and surprisingly no metal‐catalyzed atroposelective N‐arylations have been described. Herein, we disclose an unprecedented Cu‐catalyzed atroposelective N−C coupling that proceeds at room temperature. Such mild reaction conditions, which are a crucial parameter for atropostability of the newly generated products, are operative thanks to the use of hypervalent iodine reagents as a highly reactive coupling partners. A large panel of the N−C axially chiral compounds was afforded with very high enantioselectivity (up to >99 % ee) and good yields (up to 76 %). Post‐modifications of thus accessed atropisomeric compounds allows further expansion of the diversity of these appealing compounds.
Observation of Ion Electrosorption in Metal–Organic Framework Micropores with In Operando Small‐Angle Neutron Scattering
Authors: He Lilin , Yang Luming , Dincă Mircea , Zhang Rui , Li Jianlin
Published: March 2020

A molecular‐level understanding of transport and adsorption mechanisms of electrolyte ions in nanoporous electrodes under applied potentials is essential to control the performance of double‐layer capacitors. Here, in operando small‐angle neutron scattering (SANS) is used to directly detect ion movements into the nanopores of a conductive metal–organic framework (MOF) electrode under operating conditions. Neutron‐scattering data reveals that most of the void space within the MOF is accessible to the solvent. Upon the addition of the electrolyte sodium triflate (NaOTf), the ions are adsorbed on the outer surface of the protrusions to form a 30 Å layer instead of entering the ionophobic pores in the absence of an applied charging potential. The changes in scattering intensity when potentials are applied suggests the ion rearrangement in the micropores following different mechanisms depending on the electrode polarization. These observations shed insights on ion electrosorption in electrode materials.
Strong and Confined Acids Control Five Stereogenic Centers in Catalytic Asymmetric Diels–Alder Reactions of Cyclohexadienones with Cyclopentadiene
Authors: Ghosh Santanu , Das Sayantani , De Chandra Kanta , Yepes Diana , Neese Frank , Bistoni Giovanni , Leutzsch Markus , List Benjamin
Published: March 2020

We describe a highly enantioselective Diels–Alder reaction of cross‐conjugated cyclohexadienones with cyclopentadiene, in which five stereocenters are effectively controlled by a strongly acidic and confined imidodiphosphorimidate catalyst. Our approach provides tricyclic products in excellent stereoselectivity. We also report methods to convert the obtained products into useful intermediates and a computational study that aids in gaining deeper insight into the reaction mechanism and origin of stereoselectivity.
Enantiocomplementary Epoxidation Reactions Catalyzed by an Engineered Cofactor‐Independent Non‐natural Peroxygenase
Authors: Xu Guangcai , Crotti Michele , Saravanan Thangavelu , Kataja Kim M. , Poelarends Gerrit J.
Published: March 2020

Peroxygenases are heme‐dependent enzymes that use peroxide‐borne oxygen to catalyze a wide range of oxyfunctionalization reactions. Herein, we report the engineering of an unusual cofactor‐independent peroxygenase based on a promiscuous tautomerase that accepts different hydroperoxides (t‐BuOOH and H2O2) to accomplish enantiocomplementary epoxidations of various α,β‐unsaturated aldehydes (citral and substituted cinnamaldehydes), providing access to both enantiomers of the corresponding α,β‐epoxy‐aldehydes. High conversions (up to 98 %), high enantioselectivity (up to 98 % ee), and good product yields (50–80 %) were achieved. The reactions likely proceed via a reactive enzyme‐bound iminium ion intermediate, allowing tweaking of the enzyme's activity and selectivity by protein engineering. Our results underscore the potential of catalytic promiscuity for the engineering of new cofactor‐independent oxidative enzymes.
Creation of Al‐Enriched Mesoporous ZSM‐5 Nanoboxes with High Catalytic Activity: Converting Tetrahedral Extra‐Framework Al into Framework Sites by Post Treatment
Authors: Jiao Yilai , Forster Luke , Xu Shaojun , Chen Huanhao , Han Jingfeng , Liu Xuqing , Zhou Yangtao , Liu Jinmin , Zhang Jinsong , Yu Jihong , D'Agostino Carmine , Fan Xiaolei
Published: March 2020

ZSM‐5 zeolite nanoboxes with accessible meso‐micro‐pore architecture and strong acid sites are important in relevant heterogeneous catalysis suffering from mass transfer limitations and weak acidities. Rational design of parent zeolites with concentrated and non‐protective coordination of Al species can facilitate post‐synthetic treatment to produce mesoporous ZSM‐5 nanoboxes. In this work, a simple and effective method was developed to convert parent MFI zeolites with tetrahedral extra‐framework Al into Al‐enriched mesoporous ZSM‐5 nanoboxes with low silicon‐to‐aluminium ratios of ≈16. The parent MFI zeolite was prepared by rapid ageing of the zeolite sol gel synthesis mixture. The accessibility to the meso‐micro‐porous intra‐crystalline network was probed systematically by comparative pulsed field gradient nuclear magnetic resonance diffusion measurements, which, together with the strong acidity of nanoboxes, provided superb catalytic activity and longevity in hydrocarbon cracking for propylene production.
Nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands: Syntheses and their catalytic performance for (co)polymerization of norbornene
Authors: He Xiaohui , Zhu Chuanyi , Huang Shengmei , Duan Yapeng , Zhang Feng , Cheng Changwen , Wang Kai , Guo Yan , Wu Bin , Wen Yufei , Zou Jianhua , Chen Defu
Published: March 2020

Novel nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands, bis‐(salicylaldnaphthylmethyleneimino)Ni(II) (Ni{(3‐R1)(5‐R2)C6H2(O)CH[N (naphthyl‐CH2)]}2 Ni1: R1 = H, R2 = H; Ni2: R1 = H, R2 = CH3; Ni3: R1 = H, R2 = Br; Ni4: R1 = H, R2 = OCH3; Ni5: R1 = CH3, R2 = H; Ni6: R1 = Br, R2 = H), were synthesized. Ni2, Ni3, Ni5, and Ni6 are clearly characterized by single‐crystal X‐ray diffraction. Co‐polymerization of norbornene (NB) with 5‐norbornene‐2‐methylene butyl ether (BN) was carried out in toluene with the aforesaid complexes as catalyst precursors and B(C6F5)3 as the co‐catalyst. Catalyst activity, molecular weight, thermal stability, solubility, regularity, and optical transparency were investigated, and the mechanism of the electron groups changing catalyst performance is explained. All catalysts show high activity toward co‐polymerization (up to 3.53 × 105 gpolymer molNi−1 h−1). Ni3 shows the highest activity and Ni5 shows the highest insertion rate (up to 37.6%). The obtained poly(NB‐co‐BN)s are confirmed to be vinyl‐addition‐type co‐polymers, and they are noncrystalline. The co‐polymers exhibited excellent thermal stability and processability (Td ≥ 400 °C, Tg < 240 °C), optical transparency (up to 90%), and good solubility.
Ammonium ion removal using activated zeolite and chitosan
Authors: Safie Nurliyana Nasuha , Zahrim Yaser Abu , Hilal Nidal
Published: March 2020

Studies have previously been done on efficacies of chitosan and zeolite in ammonium ion (NH4+) removal. However, no study compares the adsorption performance of natural zeolite (NZ) and activated NZ (ANZ) with high molecular weight chitosan (HMWC) and low molecular weight chitosan (LMWC). Hence, this study investigates the potentials of NZ, ANZ, LMWC, and HMWC in NH4+ removal. The characteristics of NZ, ANZ, LMWC, and HMWC such as functional groups, surface morphology, elemental composition, zeta potential, and particle size was also investigated. The deposition of NH4+ on the surface of NZ and ANZ was confirmed with the absence of nitrogen by the adsorption spectrum of energy dispersive X‐ray (EDX) and supported by the presence of an Fourier transform infrared (FTIR) stretching band at ~3,500–3,300 cm−1, as well as broader and less intense bands ~1,600 cm−1 after the adsorption for all the adsorbents. The particle size of LMWC, HMWC, NZ, and ANZ were 98, 813, 22,354, and 9,826 nm, respectively. Meanwhile, after the activation process, the composition of O, Si, Al, Fe, Ca, and Na was reduced. NH4+ batch adsorption was also studied. HMWC, NZ, and ANZ reached adsorption equilibrium at 15 h, meanwhile for LMWC, the equilibrium reached at t = 20 h. The adsorption capacity of LMWC, HMWC, NZ, and ANZ at an initial concentration of 50 mg/L was 0.769, 0.331, 2.162, and 2.937 mg/g, respectively.
Preparation and properties of polybutylene‐terephthalate/graphene oxide in situ flame‐retardant material
Authors: Li Zhengqiu , Li Wen , Liao Li , Li Jianbin , Wu Ting , Ran Longchang , Zhao Tianbao , Chen Baoshu
Published: March 2020

In this manuscript, an in situ layered intumescent flame retardant (IFR) of graphene oxide (GO) was used to produce a polybutylene terephthalate (PBT) flame‐retardant material with different flame‐retardant concentration gradients. IFR was introduced into the GO layered structure via a chemical reaction to achieve an in situ flame‐retardant effect. The elements of the composite were characterized using energy dispersive spectroscopy. The results showed that although the subsequent PBT‐based flame‐retardant composites displayed low flame‐retardant content, it exhibited excellent flame retardancy and mechanical properties. Due to the introduction of GO, the flame retardancy of the composites was improved significantly. The lamellar structure of GO provided a barrier allowing it to absorb condensed nucleus compounds. Therefore, continuous and compact scaly carbon layers were formed in the matrix during the burning process.
Synthesis of isocyanurate‐based imidazole carboxylate as thermal latent curing accelerator for thermosetting epoxy resins
Authors: Sun Xin , Wang Yiming , Tang Yuyao , Zhang Bowen , Wei Wei , Li Xiaojie , Fei Xiaoma , Liu Xiaoya
Published: March 2020

A novel thermal latent curing accelerator, 1‐(2‐cyanoethyl)‐2‐methylimidazole/tris (2‐carboxyethyl) isocyanurate adduct (2MICN‐T), was successfully synthesized through an acid–base neutralization of tris(2‐carboxyethyl)isocyanurate (TCEIC) and 1‐(2‐cyanoethyl)‐2‐methylimidazole (2MICN). It was further added into diglycidylether of bisphenol A based epoxy resin/methylhexahydrophthalic anhydride mixture to form one‐component curing systems. With the addition of 2 wt% of 2MICN‐T, the one‐component system could be steadily stored for more than 1 month at room temperature, while the shelf life of 2MICN curing system was only 2 days. Nonisothermal differential scanning calorimeter also demonstrated the excellent thermal latency of 2MICN‐T in low‐temperature region and rapid initiation of the curing reaction when raising temperature. Compared to the cured resins with original 2MICN as accelerator, the resulted thermosets exhibited enhanced glassy storage modulus, glass transition temperature, and thermal stability when 2 wt% of 2MICN‐T was applied. It was attributed to the chemical incorporation of the isocyanurate moieties with multi carboxyl groups and nitrogen‐contained heterocyclic ring, effectively increasing the crosslinking density, chain rigidity, and heat resistance of the cured resin. Thus, it is suggested that 2MICN‐T can play both roles as latent curing accelerator and modifier for one‐component epoxy compounds, and is particularly recommended for application in electronic packaging fields.
Synthesis and docking study of benzimidazole–triazolothiadiazine hybrids as aromatase inhibitors
Authors: Acar Çevik Ulviye , Sağlık Begüm N. , Osmaniye Derya , Levent Serkan , Kaya Çavuşoğlu Betül , Karaduman Abdullah B. , Özkay Yusuf , Kaplancıklı Zafer A.
Published: March 2020

Aromatase is involved in the biosynthesis of estrogen and thus is a critical target for breast cancer. In this study, to identify new aromatase enzyme inhibitors, seven 3‐[4‐(5‐methyl‐1H‐benzo[d]imidazol‐2‐yl)phenyl]‐6‐(substituted phenyl)‐7H‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazine derivatives were synthesized. First, a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay was performed to determine the inhibitory activity of the synthesized compounds on the MCF‐7 cell line. The aromatase inhibitory activity was determined for the active compounds 5b, 5c, 5e, and 5g on the MCF‐7 cell line. Compound 5g showed significant aromatase inhibitory activity (IC50 = 0.037 ± 0.001 µM). Interestingly, this compound, which bears a difluoro substituent at positions 2 and 4 of the phenyl ring, displayed the most potent aromatase inhibitory activity without significant cytotoxicity to a normal healthy cell line (NIH3T3). Furthermore, the interactions between the best active compounds and the active site of the enzyme were analyzed through a docking study. The results of this study determined that benzimidazole–triazolothiadiazine derivatives are promising compounds that should be further developed as a novel class of aromatase inhibitors.
Effects and Mechanisms of Exogenous Electromagnetic Field on Bone Cells: A Review
Authors: Zhang Bin , Xie Yangli , Ni Zhenhong , Chen Lin
Published: March 2020

Osteoporosis, fractures, and other bone diseases or injuries represent serious health problems in modern society. A variety of treatments including drugs, surgeries, physical therapies, etc. have been used to prevent or delay the progression of these diseases/injuries with limited effects. Electromagnetic field (EMF) has been used to non‐invasively treat bone diseases, such as fracture and osteoporosis, for many years. However, because a variety of cellular and molecular events can be affected by EMF with various parameters, the precise bioeffects and underlying mechanisms of specific EMF on bone cells are still obscure. Here, we summarize the common therapeutic parameters (frequency and intensity) of major types of EMF used to treat bone cells taken from 32 papers we selected from the PubMed database published in English from 1991 to 2018. Briefly, pulse EMF promotes the proliferation of osteoblasts when its frequency is 7.5–15 Hz or 50–75 Hz and the intensity is 0.40–1.55 mT or 3.8–4 mT. Sinusoidal EMF, with 0.9–4.8 mT and 45–60 Hz, and static magnetic field with 0.1–0.4 mT or 400 mT, can promote osteoblast differentiation and maturation. Finally, we summarize the latest advances on the molecular signaling pathways influenced by EMF in osteoblasts and osteoclasts. A variety of molecules such as adenosine receptors, calcium channels, BMP2, Notch, Wnt1, etc., can be influenced by EMF in osteoblasts. For osteoclasts, EMF affects RANK, NF‐κB, MAPK, etc. We speculate that EMF with different frequencies and intensities exert distinct bioeffects on specific bone cells. More high‐quality work is required to explore the detailed effects and underlying mechanisms of EMF on bone cells/skeleton to optimize the application of EMF on bone diseases/injuries. Bioelectromagnetics. 2020;41:263–278 © 2020 Bioelectromagnetics Society.
Creating sites of community education and democracy: Henry Morris and the Cambridgeshire village colleges. A reflection 90 years on from their inception
Authors: Hopkins Neil
Published: March 2020

This article investigates the work of Henry Morris (1889–1961), in particular his ideas on the Cambridgeshire village colleges. It is now 90 years since the first of these was founded in Sawston in 1930, and the article aims to address the issue of whether Morris’s views on education and democracy encapsulated in the village colleges still have relevancy in the early twenty‐first century. An overview of Morris’s career and the creation of the village colleges is investigated, using the work of Paul Hirst and associative democracy as a theoretical lens. It is argued that the Cambridgeshire village colleges do have some attributes of associative democracy, particularly their original emphasis as sites of local democracy and participation from voluntary bodies and private individuals. However, Morris’s role as Cambridgeshire’s Chief Education Officer (1922–1954) meant that the local state (in the guise of the County Council) played a more significant role in the village colleges than Hirst advocates for his version of associative democracy. As English primary and secondary schools turn from local authority control to academy status, Morris’s vision for local schools of and for local people is becoming increasingly compromised. The article ends with the work of Allen and Gann, both influenced by Morris, who argue for a revitalised form of comprehensive schooling and lifelong learning that again sees educational institutions as sites of grassroots democracy.
Beyond heuristics: CFD‐based novel multiparameter scale‐up for geometrically disparate bioreactors demonstrated at industrial 2kL–10kL scales
Authors: Scully James , Considine Laura B. , Smith Mark T. , McAlea Eamonn , Jones Nephi , O'Connell Edel , Madsen Emilee , Power Martin , Mellors Philip , Crowley John , O'Leary Niall , Carver Scott , Van Plew Daniel
Published: March 2020

The timely delivery of the most up‐to‐date medicines and drug products is essential for patients throughout the world. Successful scaling of the bioreactors used within the biopharmaceutical industry plays a large part in the quality and time to market of these products. Scale and topology differences between vessels add a large degree of complication and uncertainty within the scaling process. Currently, this approach is primarily achieved through extensive experimentation and facile empirical correlations, which can be costly and time consuming while providing limited information. The work undertaken in the current study demonstrates a more robust and complete approach using computational fluid dynamics (CFD) to provide potent multiparameter scalability, which only requires geometric and material properties before a comprehensive and detailed solution can be generated. The CFD model output parameters that can be applied in the scale‐up include mass transfer rates, mixing times, shear rates, gas hold‐up values, and bubble residence times. The authors examined three bioreactors with variable geometries and were able to validate them based on single‐phase and multiphase experiments. Furthermore, leveraging the resulting CFD output information enabled the authors to successfully scale‐up from a known 2kL to a novel and disparate 5kL single‐use bioreactor in the first attempted cell culture. This multiparameter scaling approach promises to ultimately lead to a reduction in the time to market providing patients with earlier access to the most groundbreaking medicines.
Mechanism of the oxidative stress‐mediated increase in lipid accumulation by the bacterium, R. opacus PD630: Experimental analysis and genome‐scale metabolic modeling
Authors: Sundararaghavan Archanaa , Mukherjee Amitava , Sahoo Swagatika , Suraishkumar G. K.
Published: March 2020

Appropriate species of oleaginous bacteria, with their high growth rates and lipid accumulation capabilities, can be good contenders for industrial triacylglycerol (TAG) production, compared to microalgae. Further, oxidative stress (OS) can be used to significantly increase TAG yields in oleaginous microbes, but the mechanism is unexplored. In a first, this study explored the mechanism behind OS‐mediated increase in TAG accumulation by the bacterium, Rhodococccus opacus PD630, through experimental analysis and metabolic modelling. Two mechanisms that could increase acetyl‐CoA (TAG‐precursor) levels were hypothesized based on literature information. One was OS‐mediated inactivation of the aconitase (TCA cycle), and another was the inactivation of the triosephosphate isomerase (TPI; glycolysis). The results negated the involvement of aconitase in increased acetyl‐CoA levels. Analysis of the metabolic model showed that inactivation of TPI, re‐routed the flux through the pentose phosphate pathway (PPP), supplying both NADPH and acetyl‐CoA for TAG synthesis. Additionally, inactivation of TPI increased TAG flux by 143%, whereas, inactivating both TPI and aconitase, increased it by 152%. We present experimental evidence for OS‐mediated decrease in TPI activity and increase in activity of glucose‐6‐phosphate dehydrogenase (PPP enzyme). The findings indicate that increased flux through PPP can be explored to improve TAG accumulation on a large‐scale.
Bring mental health issues out of the shadows, into the light
Authors: McCarthy Claudine
Published: March 2020

ANAHEIM, Calif. — As a New Jersey State Trooper who went undercover to infiltrate the mob in the 1970s, Bob Delaney had no problem remaining calm, cool, and collected as he chatted up members of the Bruno and Genovese crime families while he was wearing a wire. The stress of the situation surfaced as he drove away from such interactions and had to quickly find the nearest gas station because he became sick to his stomach. He didn't know it at the time, but years later he learned the feelings he experienced were actually post‐traumatic stress disorder. His battle prompted him to launch a mental health awareness campaign, with a special focus on the military and athletes. After Delaney's undercover days, he had another successful career as a basketball official and as the NBA's Vice President of Referee Operations and Director of Officials.
Choose to fly higher rather than pacing around
Authors: Musumeci Giuseppe , Aranzulla Tiziana Claudia
Published: March 2020

Key Points

Pre‐existing right bundle branch block and the depth of the prosthesis in the left ventricle are predictors of permanent pacemaker implantation (PPI) following transcatheter aortic valve replacement.

The recapturable capability of the Evolut R system allows higher and more precise valve implantation and this was associated with halved incidence of PPI as compared with the CoreValve.

Larger studies are needed to assess the feasibility of systematic very high implantation (depth in the left ventricle outflow tract ≤3 mm) of the Evolut R and the associated rate of PPI.
BATMAN—Savior or vigilante?
Authors: Khan Jaffar M. , Lederman Robert J.
Published: March 2020

Key Points

BATMAN is a new technique to prevent left ventricular outflow tract (LVOT) obstruction from transcatheter mitral valve replacement (TMVR) by deploying the transcatheter heart valve from the apex through a perforation of the anterior mitral valve leaflet.

The risks of uncontrolled balloon dilatation of the anterior mitral valve leaflet include extension of the tear superiorly into the aorto‐mitral curtain or laterally to avulse the trigone from the annulus.

Percutaneous laceration of the anterior mitral leaflet, pre‐emptive alcohol septal ablation, and transatrial leaflet resection are alternative strategies that prevent LVOT obstruction from TMVR
Combined alcohol septal ablation and transcatheter aortic valve replacement: Drunk and playing with fire
Authors: Rowin Ethan J. , Kimmelstiel Carey
Published: March 2020

Key Points

Evaluation of the severity of aortic stenosis in the presence of dynamic left ventricular outflow (LVOT) obstruction is challenging.

Invasive hemodynamic assessment with provocative maneuvers can be useful to differentiate of the relative components of obstruction.

In patients with both dynamic LVOT obstruction and aortic stenosis, surgical myectomy and concurrent surgical aortic valve replacement is the optimal treatment strategy; combined alcohol septal ablation and transcatheter aortic valve replacement should only be considered for very high surgical risk patients.
Effects of different cultivars and particle sizes of non‐degermed millet flour fractions on the physical and texture properties of Chinese steamed bread
Authors: Li Shao‐Hui , Zhao Wei , Li Peng‐Liang , Min Guang , Zhang Ai‐Xia , Zhang Jia‐Li , Liu Ying‐Ying , Liu Jing‐Ke
Published: March 2020

Background and objectives

We studied the effects of different cultivars of non‐degermed millet flour fraction and the particle size on Chinese steamed bread to promote the industrial development of the whole‐grain food industry.

Findings

We used a texture analyzer to analyze the changes introduced by different cultivars of non‐degermed millet flour fraction, and the effect of its particle size on the hardness, adhesiveness, springiness, gumminess, and chewiness parameters, based on the analysis of height‐to‐diameter ratio and specific volume. We obtained samples of different particle size fractions by using 40, 60, 80, 100, 120, and 140 mesh sieves and determined that the particle substitution of non‐degermed millet flour fraction was at a level of 30%. We conducted partial least squares discriminant analysis (PLS‐DA) screening to identify the signature differences of quality components.

Conclusions

According to Hunter Laboratory values (whiteness/darkness, L*; redness/greenness, a*; and yellowness/blueness, b*), the results indicated that as the particle size decreased, the L* and whiteness index (W) values decreased but the a* and b* values increased, and the hardness, cohesiveness, adhesiveness, springiness, gumminess, and chewiness parameters of Chinese steamed bread with different particle sizes were significantly different (p < .05).

Significance and novelty

Partial least squares discriminant analysis could distinguish japonica cultivar samples and glutinous cultivar samples. According to the variable influence on projection (VIP) values, we screened chewiness, gumminess, and hardness as the signature differences of the quality components.
Factors Governing the Activity of α‐MnO2 Catalysts in the Oxygen Evolution Reaction: Conductivity versus Exposed Surface Area of Cryptomelane
Authors: Heese‐Gärtlein Justus , Morales Dulce M. , Rabe Anna , Bredow Thomas , Schuhmann Wolfgang , Behrens Malte
Published: March 2020

Cryptomelane (α‐(K)MnO2) powders were synthesized by different methods leading to only slight differences in their bulk crystal structure and chemical composition, while the BET surface area and the crystallite size differed significantly. Their performance in the oxygen evolution reaction (OER) covered a wide range and their sequence of increasing activity differed when electrocatalysis in alkaline electrolyte and chemical water oxidation using Ce4+ were compared. The decisive factors that explain this difference were identified in the catalysts’ microstructure. Chemical water oxidation activity is substantially governed by the exposed surface area, while the electrocatalytic activity is determined largely by the electric conductivity, which was found to correlate with the particle morphology in terms of needle length and aspect ratio in this sample series. This correlation is rather explained by an improved conductivity due to longer needles than by structure sensitivity as was supported by reference experiments using H2O2 decomposition and carbon black as additive. The most active catalyst R‐cryptomelane reached a current density of 10 mA cm−2 at a potential 1.73 V without, and at 1.71 V in the presence of carbon black. The improvement was significantly higher for the catalyst with lower initial activity. However, the materials showed a disappointing catalytic stability during alkaline electrochemical OER, whereas the crystal structure was found to be stable at working conditions.
Preparation, Photophysical and Electrochemical Evaluation of an Azaborondipyrromethene/Zinc Porphyrin/Graphene Supramolecular Nanoensemble
Authors: Rotas Georgios , Thomas Michael B. , Canton‐Vitoria Ruben , D'Souza Francis , Tagmatarchis Nikos
Published: March 2020

The preparation of an entirely supramolecular, multichromophoric azaborondipyrromethene (ABDP)/zinc tetraphenylporphyrin (ZnTPP)/exfoliated graphene (GR) nanoensemble was accomplished. The ABDP derivative bears glycol chains for enhancing solubility and a pyridine functionality for allowing coordination with ZnTPP. The ABDP/ZnTPP/GR nanoensemble was characterized in terms of morphology and composition by using complementary microscopy imaging, thermogravimetric analysis, Raman as well as steady‐state and time‐resolved absorption and emission spectroscopy. The photophysical and electrochemical assessment of ABDP/ZnTPP/GR as well as the binding properties of the ABDP/ZnTPP complex, employed as a reference, are presented. Energy and electron transfer events were observed in ABDP/ZnTPP upon photoexcitation. However, in the case of ABDP/ZnTPP/GR, the graphene‐induced aggregation of the chromophores alters their electronic interactions, enhancing the energy/electron transfer process between them.
Stimuli‐Responsive Purely Organic Room‐Temperature Phosphorescence Materials
Authors: Huang Lili , Qian Chen , Ma Zhiyong
Published: March 2020

This Minireview summarizes the recent progress of stimuli‐responsive purely organic phosphorescence materials. Organic phosphorescence is closely related to the intermolecular interactions, because such interactions are beneficial to promote spin orbital coupling (SOC) and boost intersystem cross (ISC) efficiency and finally are conducive to satisfactory phosphorescence. It is found that the intermolecular interactions, which are essential for organic phosphorescence, are easily disturbed by external stimuli such as mechanical force, photon, acid, chemical vapor, leading to the luminescence change. According to this principle, various purely organic phosphorescence materials sensitive to external stimuli have been developed. This Minireview categorizes reported stimuli‐responsive purely organic phosphorescence materials on the basis of different stimuli, including mechanochromism, mechanoluminescence, photoactivity, acid‐responsiveness and other stimuli. Some prospective strategies for constructing stimuli‐responsive purely organic phosphorescence molecules are provided.