bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovery of Elusive K4O6, a Compound Stabilized by Configurational Entropy of Polarons
Authors: Freysoldt Christoph , Merz Patrick , Schmidt Marcus , Mohitkar Shrikant , Felser Claudia , Neugebauer Jörg , Jansen Martin
Published: October 2018

Synthesis of elusive K4O6 has disclosed implications of crucial relevance for new solid materials discovery. K4O6 forms in equilibrium from K2O2 and KO2, in an all‐solid state, endothermic reaction at elevated temperature, undergoing back reaction upon cooling to ambient conditions. This tells that the compound is stabilized by entropy alone. Analyzing possible entropic contributions reveals that the configurational entropy of “localized” electrons, i.e., of polaronic quasi‐particles, provides the essential contribution to the stabilization. We corroborate this assumption by measuring the relevant heats of transformation and tracking the origin of entropy of formation computationally. These findings challenge current experimental and computational approaches towards exploring chemical systems for new materials by searching the potential energy landscape: one would fail in detecting candidates that are crucially stabilized by the configurational entropy of localized polarons.
Absorptive Hydrogen Scavenging for Enhanced Aromatics Yield During Non‐oxidative Methane Dehydroaromatization on Mo/H‐ZSM‐5 Catalysts
Authors: Kumar Anurag , Song Kepeng , Liu Lingmei , Han Yu , Bhan Aditya
Published: October 2018

Addition of Zr metal particles to MoCx/ZSM‐5 in interpellet mixtures (2:1 weight ratio) resulted in maximum single‐pass methane conversion of 27 % for dehydroaromatization at 973 K (in significant excess of the equilibrium prescribed circa 10 % conversion at these conditions) and a concurrent 1.4–5.6‐fold increase in aromatic product yields due to circumvention of thermodynamic equilibrium limitations by absorptive H2 removal by Zr while retaining cumulative aromatic product selectivity. The absorptive function of the polyfunctional catalyst formulation can be regenerated by thermal treatment in He flow at 973 K, yielding above‐equilibrium methane conversion in successive regeneration cycles. H2 uptake experiments demonstrate formation of bulk ZrH1.75 on hydrogen absorption by Zr at 973 K. Cooperation between absorption and catalytic centers distinct in location and function enables circumvention of persistent thermodynamic challenges in non‐oxidative methane dehydrogenation.
Transition metal complexes containing a tridentate cefadroxil‐based Schiff base: An effective paramagnetic semiquinone Ag (I) complex against Staphylococcus aureus and Pseudomonas aeruginosa
Authors: Anacona J.R. , Barrios Virginia , Bravo Alina , Celis Freddy
Published: October 2018

The aim of this study was to prepare transition metal complexes containing a cefadroxil‐based Schiff base ligand (H2L, 3) obtained from the condensation of cefadroxil 1 with salicylaldehyde 2, and to study their bactericidal activity against G(+) and G(–) strains. Spectroscopic and physicochemical techniques, namely, transmission electron microscopy, UV–Vis, Fourier transform‐infrared, electron paramagnetic resonance, 1H NMR, mass spectrometry, magnetic susceptibility, molar conductance, molecular modelling, together with elemental and thermal analyses were used to find out the binding mode and composition of these complexes. Based on the characterization studies, the general formulae [ML (H2O)3], where M = Mn 4, Co 5, Ni 6, Zn 7 and Ag 8, were proposed for the complexes. The Schiff base 3 behaved as a dianionic tridentate OOO chelating agent. An octahedral geometry for all the complexes was suggested on the basis of magnetic and spectral data. Free 1, 3 and its metal complexes 4–8 were tested for bactericidal activity by using both agar disc diffusion method and the minimal inhibitory concentration. In vitro bacterial viability revealed that 3 and complexes 4–7 had similar bactericidal activity than 1 against Staphylococcus epidermidis showing that they have good activity as bactericides. Based on magnetic data, the paramagnetic complex 8 was shown to be a semiquinone complex stabilized by the metal, and exhibited much better bactericidal activity than 1 against all bacterial strains tested.
Synthesis, structure, antiproliferative activity and molecular docking of divalent and trivalent metal complexes of 4H‐3,5‐diamino‐1,2,4‐triazole and α‐hydroxynaphthaldehyde Schiff base ligand
Authors: El‐Ghamry Hoda , El‐Wakiel Nadia , Khamis Abeer
Published: October 2018

Cu(II), Co(II), Mn(II), Cr(III) and Mn(III) chelates of the ligand obtained by the condensation of 4H‐3,5‐diamino‐1,2,4‐triazole and 2‐hydroxy‐1‐naphthaldehyde have been isolated and characterized by means of elemental analysis, inductively coupled plasma analysis, mass spectrometry, Fourier transform infrared and UV–visible spectroscopies, magnetic measurements and thermal analysis. The analytical results indicated the formation of the metal complexes in a ligand‐to‐metal molar ratio of 1:2. The ligand is connected to the metal ion in a tetradentate fashion coordinating to the metal center through the azomethine nitrogens and deprotonated phenolic OH groups. The spectral and magnetic results supported the formation of octahedral geometry around the Cu(II), Mn(III) and Cr(III) centers while Co(II) and Mn(II) centers were confirmed to have tetrahedral geometry. Molecular docking was used to predict the binding between the ligand and the oncogenic protein H‐ras (121p). The antiproliferative activity of the compounds under study was evaluated in vitro using MTT assay against liver carcinoma (HepG2) and breast cancer (MCF‐7) cell lines comparing with cisplatin. The binding mode of selected metal chelates with salmon serum DNA was investigated using the electronic absorption titration method.
Synthesis of fluorinated polypropylene using CuAAC click chemistry
Authors: Acik G. , Cansoy C. Elif , Tasdelen M. A.
Published: October 2018

Synthesis of fluorine containing polypropylene (PPF) from chlorinated polypropylene (PPCl) via Cu(I) catalyzed Huisgen type 1,3‐dipolar cycloaddition (CuAAC) and its water repellency properties are demonstrated. Initially, clickable azido‐functional polypropylene (PPN3) and alkyne‐functionalized fluorine compound (FAl) are independently prepared by nucleophilic substitution of PPCl with azidotrimethylsilane‐tetrabutylammonium fluoride and esterification reactions of 2,2,3,3,4,4,5,5‐octafluoro‐1‐pentanol with 4‐pentyonic acid. The CuAAC reaction between PPN3and FAl leads to corresponding PPF under mild conditions. The chemical structures and surface properties of desired PPF are characterized by Fourier transform infrared,1H‐NMR, differential scanning calorimetry, scanning electron microscopy, atomic force microscope, and contact angle analyses. Based on water contact angle (WCA) measurement, it is found that both PPCl and PPN3films have shown similar hydrophobicity, whereas the WCA of PPF is surprisingly decreased due to the presence of ester and triazole groups coming from FAl compound and the clicked product. This facile modification procedure could be utilized in order to alter the wetting or thermal properties of the commercial polymers for potential applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47072.
Effect of the molecular weight on the plasticization properties of poly(hexane succinate) in poly(vinyl chloride) blends
Authors: Gao Chuanhui , Wang Bo , Hu Zunfu , Liu Yuetao , Wang Huizi , Zhang Xinhua , Wu Yumin
Published: October 2018

Blends of poly(vinyl chloride) (PVC) and poly(hexane succinate) (PHS) with various molecular weights were analyzed with respect to their mechanical properties, durability, and thermal stability. We found that the molecular weight of PHS played an important role in the plasticizing process, and the single glass‐transition temperature (T
g) of the PVC blends measured by dynamic mechanical analysis supported the complete miscibility between PHS and PVC. The plasticizing efficiency of PHS increased as the molecular weight increased; this reflected the gradually increasing elongation at break and the decreased T
g of the PVC blend. Meanwhile, the higher molecular weight of PHS also improved the resistance of migration and thermal stability but decreased the biodegradability of the PVC blends; this was due to the strong intermolecular interactions between PHS and PVC. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47081.
Fabrication of honeycomb‐structured protein arrays via one‐step method
Authors: Ju Yuanlai , Ding Lingyun , Zhu Jiafeng , Sun Wei
Published: October 2018

“Inverse emulsion”‐“breath figures” (Ie‐BF) method was introduced for fabricating porous films with protein arrays decorating the interior of the obtained polymeric pores. Compared with the traditional BF method in which only hydrophobic or amphiphilic components could be used, Ie‐BF method created a system with water phase carrying water‐soluble protein before solution casting, which makes it possible to obtain patterned protein arrays within the BF structure in one‐step. The stability of the inverse emulsion system is an intractable problem solved by high shearing emulsification. Experimental parameters, including the concentration of the matrix polymer, water/oil ratio of the IE, amount of both emulsifier and protein in IE, were evaluated for establishing an optimal condition to prepare fine BF arrays by following the Ie‐BF method. Proteins tagged with fluorescein isothiocyanate were added into the emulsion to cast films, and pores efficiently enriched by proteins were revealed by the images of fluorescence microscope, indicating the successful preparation of protein arrays. Among all the approaches of establishing patterned structures of biomacromolecules, Ie‐BF shows promising potential in future applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47084.
Simple preparation and characterization of molecularly imprinted nylon 6 nanofibers for the extraction of bisphenol A from wastewater
Authors: Ardekani Razieh , Borhani Sedigheh , Rezaei Behzad
Published: October 2018

Nylon 6 nanofibers incorporated with molecularly imprinted polymers (MIPs) were successfully fabricated by electrospinning with fiber diameters in the range 80–145 nm. Then, they were used as a new material for the extraction of selected bisphenol A (BPA) in water samples. Field emission scanning electron microscopy images revealed that the nanofibers had a smooth morphology with a good incorporation of MIPs. The Fourier transform infrared and energy‐dispersive X‐ray spectroscopy results also confirmed the formation of the MIPs in the nanofibers. Furthermore, Raman spectroscopy showed that the crystalline structure of the pristine nylon 6 nanofiber was a kind of α form, and the incorporation of MIPs led to a γ‐form structure in the nanofibers; this proved the interactions between nylon 6 and the MIPs. Adsorption studies also confirmed that the adsorption efficiency of BPA onto the molecularly imprinted polymer nanofibers (MIP‐NFs; 83.5%) was much greater than that onto nonimprinted polymer nanofibers (NIP‐NFs; 36.8%). Also, the imprinting factor was 3.4; this strongly implied the successful formation of molecularly imprinted cavities on the MIP‐NFs with a strong affinity to BPA. The maximum adsorption capacity of the MIP‐NFs was 103.8 mg/g. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47112.
Synthesis and characterization of heterocyclic core‐based polybenzoxazine matrices
Authors: Selvi M. , Devaraju S. , Vengatesan M. R. , Alagar M.
Published: October 2018

In the present work, four types of heterocyclic core‐based polybenzoxazine matrices (HC‐PBZ) developed based on pyridine, thiophene, and thiazole and their molecular structure, thermal, flame‐retardant and luminescent properties were studied and discussed. The heterocyclic core‐based benzoxazine monomers (HC‐BZ) were synthesized using two types of phenols (phenol, and 4‐hydroxyphenylacetonitrile), and two types of heterocyclic diamines [2,6‐Bis‐(4‐aminophenyl)‐4‐thiophen‐2‐yl‐pyridine (BATP) and 4‐(2‐methylthiazol‐5‐yl)‐2,6‐bis‐(4‐aminophenyl)‐pyridine (BAMTP)] with formaldehyde through Mannich reaction. The structure of the four HC‐BZ monomers was confirmed by various spectral analysis such as Fourier‐transform infrared spectroscopy (FTIR), and Nuclear magnetic resonance spectroscopy (1HNMR and13CNMR). All the four HC‐BZ monomers have the maximum range of curing temperature (Tp) between 252 and 267 °C. Data resulted from the thermal studies indicate that the HC‐PBZ exhibits betterTg,thermal stability and flame‐retardant properties. Among the four HC‐PBZ systems the thiazole based system possesses the higher value ofTgof 268 °C and thermal stability when compared to those of other matrices. It was also observed that the HC‐BZ monomers and HC‐PBZ polymers exhibit a photoluminescent (PL) emission range between 441–445 and 414–417 nm, respectively. Overall, it seems that the thiazole and thiophene based HC‐PBZ can be considered as competitive materials for luminescent applications with high thermal and flame‐retardant properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47134.
Enzyme‐mediated transglycosylation of rutinose (6‐O‐α‐l‐rhamnosyl‐d‐glucose) to phenolic compounds by a diglycosidase from Acremonium sp. DSM 24697
Authors: Mazzaferro Laura S. , Weiz Gisela , Braun Lucas , Kotik Michael , Pelantová Helena , Křen Vladimír , Breccia Javier D.
Published: October 2018

The structure of the carbohydrate moiety of a natural phenolic glycoside can have a significant effect on the molecular interactions and physicochemical and pharmacokinetic properties of the entire compound, which may include anti‐inflammatory and anticancer activities. The enzyme 6‐O‐α‐rhamnosyl‐β‐glucosidase (EC 3.2.1.168) has the capacity to transfer the rutinosyl moiety (6‐O‐α‐l‐rhamnopyranosyl‐β‐d‐glucopyranose) from 7‐O‐rutinosylated flavonoids to hydroxylated organic compounds. This transglycosylation reaction was optimized using hydroquinone (HQ) and hesperidin as rutinose acceptor and donor, respectively. Since HQ undergoes oxidation in a neutral to alkaline aqueous environment, the transglycosylation process was carried out at pH values ≤6.0. The structure of 4‐hydroxyphenyl‐β‐rutinoside was confirmed by NMR, that is, a single glycosylated product with a free hydroxyl group was formed. The highest yield of 4‐hydroxyphenyl‐β‐rutinoside (38%, regarding hesperidin) was achieved in a 2‐h process at pH 5.0 and 30 °C, with 36 mM OH‐acceptor and 5% (v/v) cosolvent. Under the same conditions, the enzyme synthesized glycoconjugates of various phenolic compounds (phloroglucinol, resorcinol, pyrogallol, catechol), with yields between 12% and 28% and an apparent direct linear relationship between the yield and the pKa value of the aglycon. This work is a contribution to the development of convenient and sustainable processes for the glycosylation of small phenolic compounds.
Die Verwandtschaft der europäischen Strauchweiden
Authors: Wagner Natascha
Published: October 2018

Die Beziehungen der europäischen Strauchweiden (Gattung Salix, Untergattungen Chamaetia und Vetrix) waren bislang völlig unklar. Im Gegensatzu zu bisherigen molekularen Methoden, die zu wenig Informationen lieferten, konnten mithilfe des modernen DNA‐Sequenzierverfahrens, dem Restriction site Associated DNA sequencing (RAD sequencing), tausende informative Positionen des Genoms detektiert werden.

Auf Basis dieser Daten konnte erstmals herausgefunden werden, dass die einzelnen beschriebenen Arten gut unterstützt werden, aber der traditionellen taxonomischen Eingruppierung aller Zwergweiden in eine gemeinsame Untergattung mithilfe der molekularen Daten klar widersprochen wird. Zwergsträucher sind offensichtlich als Anpassung an arktisch‐alpine Lebensräume mehrfach unabhängig voneinander entstanden.
Alles Zucker – oder was?
Authors: Bickel Susanne
Published: October 2018

Das Disaccharid Saccharose wird im Pflanzenreich nur in Ausnahmefällen gespeichert, z. B. in der Zuckerrübe und im Zuckerrohr. Neben diesen Weltwirtschaftspflanzen gibt es noch eine Reihe anderer Pflanzen, aus denen Zucker (Saccharose) isoliert werden kann, der häufig nur regional verwendet wird. Obgleich schon die Muttermilch durch ihren hohen Laktosegehalt süß ist, und süße Beeren und Früchte uns ihre Genießbarkeit signalisieren, sind mit Haushaltszucker gesüßte Speisen heute als Dickmacher und Krankmacher verschrien.
Die Domestikation der Ziegen
Authors: Sander Johannes
Published: October 2018

Die modernen Hausziegen gehen wahrscheinlich auf mehrere unabhängige Domestikationsereignisse im Bereich des fruchtbaren Halbmonds zurück. Dies belegen die Ergebnisse einer Sequenzvergleichsstudie, die sich mit archäologischen Befunden decken. Darüber hinaus lieferte die Studie Hinweise auf Merkmale, die während des Domestikationsprozesses besonders gefördert wurden, wie etwa die Pigmentierung oder der Milchertrag.
Haussperling: Szenen einer Ehe
Authors: Irsch Wilhelm
Published: October 2018

Bei der Synchronisation der Fortpflanzungs(aktivitäten) – insbesondere der „Feinabstimmung“ der Geschlechter – ist das Sexualverhalten ein bedeutender unmittelbarer Faktor. Dabei fällt dem männlichen Partner oft die meist wichtige aktivere Rolle zu.
„Körperwelten – Eine HERZenssache“ – Ausstellung plastinierter Organe und Körper in Osnabrück
Authors: Högermann Christiane
Published: October 2018

Eine der weltweit spektakulärsten Anatomieausstellungen des Plastinators Gunther von Hagens hat in der Osnabrücker Version als thematischen Schwerpunkt die Anatomie und (Patho‐)Physiologie des menschlichen Herzens, begleitet von einigen Ganzkörperplastinaten des Menschen in willkürlich dargestellten Posen.
Bioinformatik: Vom Gen zum Protein in silico
Authors: Haag Sara
Published: October 2018

GAAATCTGGGAGATAAGCAGT – hierbei handelt es sich nicht um die Geheimsprache eines bisher unbekannten Naturvolks, sondern wie Sie sicher gleich erkannt haben, um ein Stückchen DNA‐Sequenz. Wie übersetzt man das jetzt in die Aminosäuresequenz des kodierten Proteins? Klar, mit Hilfe einer Code‐Sonne (Abbildung 1a) oder einer Codon‐Tabelle. Doch wie macht man das eigentlich, wenn man eine ganz lange (unbekannte) DNA oder RNA Sequenz hat? Ganz einfach! Mit Hilfe des Internets am Computer …
Alle wissen's besser!
Authors: Hauk Andrea
Published: October 2018

Es wird viel diskutiert über die Vereinbarkeit von Familie und Beruf. Andrea Hauk – BIUZ‐Lesern bekannt als Autorin der Laborseite – hat den Praxistest gemacht und berichtet nun im elften Teil unserer Reihe von ihren Erfahrungen als Mutter eines Krabbelkindes.
Die Katze: Mäuseschreck und Schmusetiger
Authors: Eitner Pascal
Published: October 2018

Die Katze gehört zu den beliebtesten Haustieren und teilt mit dem Menschen eine lange Geschichte. Katzen wurden sowohl vergöttert als auch gefürchtet. Auf großen Bauernhöfen gehört die Bekämpfung von Getreideschädlingen wie Nagetieren zu ihren Hauptaufgaben. Die schnurrenden Vierbeiner werden aber auch als selbstständiges Familienmitglied oder Gesellschafter in Katzencafés geschätzt, auch wenn Katzenhaare heftige Allergien auslösen können.
Tissue and organ decellularization in regenerative medicine
Authors: Guruswamy Damodaran Rajesh , Vermette Patrick
Published: October 2018

The advancement and improvement in decellularization methods can be attributed to the increasing demand for tissues and organs for transplantation. Decellularized tissues and organs, which are free of cells and genetic materials while retaining the complex ultrastructure of the extracellular matrix (ECM), can serve as scaffolds to subsequently embed cells for transplantation. They have the potential to mimic the native physiology of the targeted anatomic site. ECM from different tissues and organs harvested from various sources have been applied. Many techniques are currently involved in the decellularization process, which come along with their own advantages and disadvantages. This review focuses on recent developments in decellularization methods, the importance and nature of detergents used for decellularization, as well as on the role of the ECM either as merely a physical support or as a scaffold in retaining and providing cues for cell survival, differentiation and homeostasis. In addition, application, status, and perspectives on commercialization of bioproducts derived from decellularized tissues and organs are addressed. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1494–1505, 2018
Effect of sulfadiazine and trimethoprim on activated sludge performance and microbial community dynamics in laboratory‐scale membrane bioreactors and sequencing batch reactors at 8°C
Authors: Kruglova Antonina , Mikola Anna , Gonzalez‐Martinez Alejandro , Vahala Riku
Published: October 2018

The effect of antibiotics sulfadiazine and trimethoprim on activated sludge operated at 8°C was investigated. Performance and microbial communities of sequencing batch reactors (SBRs) and Membrane Bioreactors (MBRs) were compared before and after the exposure of antibiotics to the synthetic wastewater. The results revealed irreversible negative effect of these antibiotics in environmentally relevant concentrations on nitrifying microbial community of SBR activated sludge. In opposite, MBR sludge demonstrated fast adaptation and more stable performance during the antibiotics exposure. Dynamics of microbial community was greatly affected by presence of antibiotics. Bacteria from classes Betaproteobacteria and Bacteroidetes demonstrated the potential to develop antibiotic resistance in both wastewater treatment systems while Actinobacteria disappeared from all of the reactors after 60 days of antibiotics exposure. Altogether, results showed that operational parameters such as sludge retention time (SRT) and reactor configuration had great effect on microbial community composition of activated sludge and its vulnerability to antibiotics. Operation at long SRT allowed archaea, including ammonium oxidizing species (AOA) such as Nitrososphaera viennensis to grow in MBRs. AOA could have an important role in stable nitrification performance of MBR‐activated sludge as a result of tolerance of archaea to antibiotics. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2708, 2019
A micro‐jet array for economic intensification of gas transfer in bioreactors
Authors: Turney D. E. , Ansari M. , Kalaga D. V. , Yakobov R. , Banerjee S. , Joshi J. B.
Published: October 2018

Bioreactors are of interest for gas‐to‐liquid conversion of stranded or waste industrial gases, such as CO, CH4, or syngas. Process economics requires reduction of bioreactor cost and size while maintaining intense production via rapid delivery of gases to the liquid phase (i.e., high kLa). Here, we show a novel bioreactor design that outperforms all known technology in terms of gas transfer energy efficiency (kLa per power density) while operating at high kLa (i.e., near 0.8 s−1). The reactor design uses a micro‐jet array to break feedstock gas into a downward microbubble flow. Hydrodynamic and surfactant measurements show the reactor's advanced performance arises from its bubble breakage mechanism, which limits fluid shear to a thin plane located at an optimal location for bubble breakage. Power dissipation and kL are shown to scale with micro‐jet diameter rather than reactor diameter, and the micro‐jet array achieves improved performance compared to classical impinging‐jets, ejector, or U‐loop reactors. The hydrodynamic mechanism by which the micro‐jets break bubbles apart is shown to be shearing the bubbles into filaments then fragmentation by surface tension rather than “cutting in half” of bubbles. Guided by these hydrodynamic insights, strategies for industrial design are given. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2710, 2019
Cyano Modification on Uridine Decreases Base‐Pairing Stability and Specificity through Neighboring Disruption in RNA Duplex
Authors: Mao Song , Ranganathan Srivathsan V. , Tsai Hsu‐Chun , Haruehanroengra Phensinee , Shen Fusheng , Valsangkar Vibhav A. , Han Bo , Hassan Abdalla E. A. , Chen Alan , Sheng Jia
Published: October 2018

5‐Cyanomethyluridine (cnm5U) and 5‐cyanouridine (cn5U), the two uridine analogues, were synthesized and incorporated into RNA oligonucleotides. Base‐pairing stability and specificity studies in RNA duplexes indicated that cnm5U slightly decreased the stability of the duplex but retained the base‐pairing preference. In contrast, cn5U dramatically decreased both base‐pairing stability and specificity between U:A and other noncanonical U:G, U:U, and U:C pairs. In addition, the cn5U:G pair was found to be stronger than the cn5U:A pair and the other mismatched pairs in the context of a RNA duplex; this implied that cn5U might slightly prefer to recognize G over A. Our mechanistic studies by molecular simulations showed that the cn5U modification did not directly affect the base pairing of the parent nucleotide; instead, it weakened the neighboring base pair in the 5′ side of the modification in the RNA duplexes. Consistent with the simulation data, replacing the Watson–Crick A:U pair to a mismatched C:U pair in the 5′‐neighboring site did not affect the overall stability of the duplex. Our work reveals the significance of the electron‐withdrawing cyano group in natural tRNA systems and provides two novel building blocks for constructing RNA‐based therapeutics.
Room‐Temperature Activation of Molecular Oxygen Over a Metal‐Free Triazine‐Decorated sp2‐Carbon Framework for Green Synthesis
Authors: Lv Li‐Bing , Yang Shi‐Ze , Feng Wei‐Jie , Ke Wen‐Yu , Zhang Bing , Jiang Zhi‐Dong , Wang Hong‐Hui , Su Juan , Li Xin‐Hao , Chen Jie‐Sheng
Published: October 2018

Additive‐free activation of oxygen molecules under ambient conditions has been a great challenge for the green organic synthesis. To make it happen, the design of highly efficient catalyst is the key to make it happen. In this work, we report a simple method to prepare an atomic‐scale carbocatalyst via decorating sp2‐carbon framework with triazine (TA−G), which can activate molecular oxygen for highly efficient organic synthesis. Both theoretical and experimental results reveal that TA−G has a Fermi level lied in the middle of the oxygen 2p antibonding orbital of the absorbed O2 to weaken the O−O bond for room‐temperature and additive‐free activation of oxygen molecules.
Supported Polyhedral Oligomeric Silsesquioxane‐Based (POSS) Materials as Highly Active Organocatalysts for the Conversion of CO2
Authors: Calabrese Carla , Liotta Leonarda F. , Giacalone Francesco , Gruttadauria Michelangelo , Aprile Carmela
Published: October 2018

Very high turnover numbers (TON) and productivity values up to 7875 and 740 respectively have been obtained for the conversion of CO2into cyclic carbonates by using hybrid materials based on imidazolium modified polyhedral oligomeric silsesquioxanes (POSS‐Imi) grafted on amorphous silica (SiO2) and mesostructured SBA‐15. The heterogeneous organocatalysts were easily preparedviaa straightforward synthetic procedure allowing to generate high local concentration spots of imidazolium active sites surrounding the POSS core. This synthetic procedure is also a promising approach for the design of a wide library of hybrid functional materials. The materials do not possess other co‐catalytic species with Lewis or Brønsted acid functionalities which still represents a challenging aspect for the outcome of the process. The recyclability of the catalysts was successfully verified for four consecutive runs. The catalytic versatility was proved with a wide range of epoxides and with the most challenging oxetane on large scale (105–210 mmol) showing higher performances in comparison with other unmodified imidazolium‐based catalytic systems. The new hybrids based on supported POSS nanostructures allowed the sustainable conversion of carbon dioxide under solvents‐ and metal‐free reaction conditions with a full selectivity toward cyclic carbonates.
Constructing Successive Active Sites for Metal‐free Electrocatalyst with Boosted Electrocatalytic Activities Toward Hydrogen Evolution and Oxygen Reduction Reactions
Authors: Zhang Quan , Luo Fang , Ling Ying , Guo Long , Qu Konggang , Hu Hao , Yang Zehui , Cai Weiwei , Cheng Hansong
Published: October 2018

As well known, heteroatom doped carbon material served as metal‐free electrocatalyst for hydrogen evolution (HER) and oxygen reduction reactions (ORR) particularly relies on the heteroatom doping level. Here, we report a 3D porous nitrogen doped carbon (PNC) electrocatalyst with superior HER and ORR electrocatalytic activities derived from the calcination of the discarded cigarette butt and dicyandiamide possessing a high nitrogen content (20 at%). PNC electrocatalyst only demands 143 mV versus RHE to achieve 10 mA cm−2 ascribed to the high nitrogen percentile in PNC electrocatalyst favorable for constructing successive active centers contributing to efficiently catalyzing HER. Ignorable degradation in HER activity observed after 10000 potential cycles as well as undetectable decay in HER performance recorded after 12 h operation indicate high stability of PNC electrocatalyst. Meanwhile, half‐wave potential of PNC electrocatalyst reaches 0.81 V versus RHE in 1 M KOH electrolyte. Additionally, stable ORR activity attained after 1000 potential cycles is indicative of high stability. A comparably high zinc‐air battery performance with maximum power density of 66 mW cm−2 is achieved by PNC electrocatalyst. This study highlights the importance of nitrogen doping level in metal‐free electrocatalyst for boosting HER and ORR activities.
Switching of Monomer Fluorescence, Charge‐Transfer Fluorescence, and Room‐Temperature Phosphorescence Induced by Aromatic Guest Inclusion in a Supramolecular Host
Authors: Ono Toshikazu , Taema Ai , Goto Aiko , Hisaeda Yoshio
Published: October 2018

Crystal engineering of three‐component crystals with guest‐dependent photoluminescence switching, including (i) crystallization‐induced emission enhancement, (ii) intermolecular charge‐transfer emission, and (iii) room‐temperature phosphorescence under ultraviolet irradiation, was demonstrated. This strategy was based on the confinement of aromatic guests in a supramolecular host (denoted as EBPDI‐TPFB) composed of 5,5′‐(ethyne‐1,2‐diyl)bis(2‐pyridin‐3‐yl‐isoindoline‐1,3‐dione (EBPDI) with two tris(pentafluorophenyl)borane (TPFB) molecules linked by B−N dative bonds that acted as Lewis pairs. The single‐crystal X‐ray structures of complexes with eight different guests were collected, revealing that the size and/or shape of the supramolecular host EBPDI‐TPFB was modulated by the included guest molecules. The excellent guest inclusion ability of EBPDI‐TPFB allowed systematic photoluminescence regulation of the complexes, which exhibited multicolor emissions in the crystalline state. Photoluminescence switching characteristics of the complexes were observed upon removing the guests or mechanical grinding of the crystals. These results indicated that using the host–guest chemistry of multicomponent crystals not only facilitates crystallization, but also can reveal hidden optical functions by combining molecules of interest, which should contribute to the fields of physical chemistry and materials science.
Electrochemical Synthesis of 5‐Aryl‐phenanthridin‐6‐one by Dehydrogenative N,C Bond Formation
Authors: Kehl Anton , Breising Valentina M. , Schollmeyer Dieter , Waldvogel Siegfried R.
Published: October 2018

Currently, the general synthesis of 5‐aryl‐phenanthridin‐6‐ones relies on the involvement of metal catalysis. Despite the urgent demand for green alternatives, avoiding synthetic routes that require transition metals for key roles is still challenging. Electrochemical efforts employing a constant potential protocol in divided cells revealed a possible alternative to the catalytic approach. A constant current protocol, undivided cells, and a remarkably low supporting electrolyte concentration enable a novel access to N‐aryl‐phenanthridin‐6‐ones by anodic N,C bond formation using directly generated amidyl radicals. Easy accessible starting materials, a broad scope of applicable functional groups, good yields, and a very simple set‐up are the benefits of this sustainable method.
Exploring Rigid and Flexible Core Trivalent Sialosides for Influenza Virus Inhibition
Authors: Kiran Pallavi , Bhatia Sumati , Lauster Daniel , Aleksić Stevan , Fleck Carsten , Peric Natalija , Maison Wolfgang , Liese Susanne , Keller Bettina G. , Herrmann Andreas , Haag Rainer
Published: October 2018

Herein, the chemical synthesis and binding analysis of functionalizable rigid and flexible core trivalent sialosides bearing oligoethylene glycol (OEG) spacers interacting with spike proteins of influenza A virus (IAV) X31 is described. Although the flexible Tris‐based trivalent sialosides achieved micromolar binding constants, a trivalent binder based on a rigid adamantane core dominated flexible tripodal compounds with micromolar binding and hemagglutination inhibition constants. Simulation studies indicated increased conformational penalties for long OEG spacers. Using a systematic approach with molecular modeling and simulations as well as biophysical analysis, these findings emphasize on the importance of the scaffold rigidity and the challenges associated with the spacer length optimization.
Rehospitalizations for complications and mortality following pacemaker implantation: A retrospective cohort study in an older population
Authors: Gillam Marianne H. , Pratt Nicole L. , Inacio Maria C. S. , Shakib Sepehr , Sanders Prashanthan , Lau Dennis H. , Roughead Elizabeth E.
Published: October 2018

Introduction

A large number of older people receive pacemakers each year but broad population‐based studies that describe complications following pacemaker implantation in this population are lacking.

Methods

We conducted a retrospective cohort study using data from the Australian Government Department of Veterans' Affairs database. The cohort consisted of patients who received a pacemaker from 2005 to 2014. The outcomes were subsequent rehospitalizations for infections, procedure‐related complications, thromboembolism, cardiovascular events (heart failure, myocardial infarction, and atrial fibrillation), and reoperation of pacemaker, and mortality.

Results

There were 10 883 pacemakers recipients, the median age was 86 years (interquartile range 83‐89), 61% were males, and 74% received a dual‐chamber pacemaker. Within 90 days postdischarge, rehospitalizations were occasioned by pacemaker infection in 0.5%, device‐related complications in 1.5%, cerebral infarction in 0.7%, and heart failure in 6% of single‐chamber pacemaker recipients. In dual‐chamber pacemaker recipients rehospitalizations were occasioned by pacemaker infection in 0.4%, septicemia in 0.4%, device‐related complications in 1.2%, cerebral infarction in 0.3%, and heart failure in 3%. Rehospitalizations for pacemaker adjustment occurred in 1.5% of patients. The 90‐day postdischarge mortality was 5% and 3% in patients with single‐ and dual‐chamber pacemaker, respectively.

Conclusion

Rehospitalizations for infection, procedure‐related complications, or thromboembolism occurred in 1% to 2% of patients within 90 days postdischarge, while 10% of single chamber and 7% of dual‐chamber recipients experienced a rehospitalization for a cardiovascular event.
The tetrafascicular nature of the intraventricular conduction system
Authors: Pérez‐Riera Andrés R. , Barbosa‐Barros Raimundo , Daminello‐Raimundo Rodrigo , de Abreu Luiz C. , Nikus Kjell
Published: October 2018

The existence of a tetrafascicular intraventricular conduction system remains debatable. A consensus statement ended up with some discrepancies and, despite agreeing on the possible existence of an anatomical left septal fascicle, the electrocardiographic and vectorcardiographic characteristics of left septal fascicular block (LSFB) were not universally accepted. The most important criteria requested to confirm the existence of LSFB is its intermittent nature. So far, our group has published cases of transient ischemia‐induced LSFB and phase 4 or bradycardia‐dependent LSFB. Finally, anatomical, anatomopathological, histological, histopathological, electrocardiographic, vectorcardiographic, body surface potential mapping, and electrophysiology studies support the fact that the left bundle branch divides into three fascicles or a “fan‐like interconnected network.”
Large‐Size Transparent Wood for Energy‐Saving Building Applications
Authors: Wang Xuan , Zhan Tianyi , Liu Yan , Shi Jiangtao , Pan Biao , Zhang Yaoli , Cai Liping , Shi Sheldon Q.
Published: October 2018

As an energy‐saving building material, transparent wood (TW) is highly attractive because of the advantages of high optical transmittance, excellent mechanical properties, and good thermal insulation. However, the current research is limited to fabricating small‐size samples in the laboratory because thick or large‐size transparent wood is almost impossible to be achieved. A method that can easily and efficiently produce transparent wood with any size and any thickness is desirable for practical applications. Transparent wood made from wood fibers as a substrate allows the cell walls to bind more tightly to the impregnated polymer, resulting in high light transmittance. Compared with wood prepared by using previously reported approaches, the transparent wood prepared by this new method not only retains the same advantages but also has higher preparation efficiency and is suitable for large‐scale production. Under a simulated real environment, the retainability of indoor temperature by a sample house utilizing the transparent wood reveals excellent thermal insulation of the fiber‐based transparent wood owing to its low thermal conductivity, showing significant benefits in saving thermal energy.
In situ and Operando Tracking of Microstructure and Volume Evolution of Silicon Electrodes by using Synchrotron X‐ray Imaging
Authors: Dong Kang , Markötter Henning , Sun Fu , Hilger André , Kardjilov Nikolay , Banhart John , Manke Ingo
Published: October 2018

The internal microstructure of a silicon electrode in a lithium ion battery was visualized by operando synchrotron X‐ray radioscopy during battery cycling. The silicon particles were found to change their sizes upon lithiation and delithiation and the changes could be quantified. It was found that volume change of a particle is related to its initial size and is also largely determined by the changing surrounding electron‐conductive network and internal interface chemical environment (e.g., electrolyte migration, solid–electrolyte interphase propagation) within fractured particles. Moreover, an expansion prolongation phenomenon was discovered whereby some particles continue expanding even after switching the battery current direction and shrinkage would be expected, which is explained by assuming different expansion characteristics of particle cores and outer regions. The study provides new basic insights into processes inside Si particles during lithiation and delithiation and also demonstrates the unique possibilities of operando synchrotron X‐ray imaging for studying degradation mechanisms in battery materials.
Power maximization from resonant electromagnetic vibration harvesters feeding bridge rectifiers
Authors: Costanzo Luigi , Lo Schiavo Alessandro , Vitelli Massimo
Published: October 2018

In this paper, it is shown that, for resonant electromagnetic vibration energy harvesters (REVEH) feeding diode bridge rectifiers, it is possible to quantify how close the ideal load condition is to the actual load condition. For this purpose, a new figure of merit, the REVEH exploitation factor (REF), is introduced. The higher the REF, the higher the REVEH exploitation. Moreover, by using the REF, a suitable technique for increasing the extracted power in a frequency region of interest is investigated. This is the frequency region where a significant energy content of the input vibrations is present. The investigated technique is based on the proper insertion of additional non‐dissipative components (capacitors or inductors) between the REVEH coil and the bridge rectifier. Experimental results confirm the validity of the theoretical analysis.
Everything Is More Critical: A Qualitative Study of the Experiences of Young Breast Cancer Survivors
Authors: Raque‐Bogdan Trisha L. , Hoffman Mary Ann , Joseph Ellen C. , Ginter Amanda C. , White Rachel , Schexnayder Kelci , Piontkowski Sarah
Published: October 2018

Receiving a breast cancer diagnosis at a young age has the potential to affect survivors' worldview and raise existential concerns. This qualitative study of 13 women diagnosed with breast cancer before the age of 40 examined how they made meaning of the impact of their cancer experience. Implementing the consensual qualitative research methodology, the authors found themes related to challenges; coping strategies; reappraisal of self, relationships with others, and life roles; and changes in views and behaviors. These findings suggest the utility of existential counseling for young breast cancer survivors' adjustment posttreatment as they attempt to cultivate a sense of control.
Electronic Effects of the Backbone on Bis(imino)pyridyliron(II)‐Catalyzed Ethylene Polymerization
Authors: Guo Lihua , Liu Yanlan , Lian Kunbo , Sun Wenting , Zhu Huaxia , Du Qing , Liu Zhe , Chen Xiaoyu , Dai Shengyu
Published: October 2018

A series of bis(imino)pyridyl iron(II) complexes 1–5 with electron‐donating and ‐withdrawing substituents on the backbone of the ligand have been synthesized and characterized. Activated with methylaluminoxane (MAO), ethylene polymerization by these iron(II) complexes was investigated in detail, involving the electronic effect and influence of reaction conditions on catalyst activity and polymer molecular weight. The electronic perturbations exert great influence on the catalytic activity of ethylene polymerization. Complexes bearing electron‐withdrawing substituents in the 4‐position of the pyridine ring showed the better activity than analogues bearing electron‐donating substituents. However, no clear trend was observed for the dependence of polymer molecular weight on these substituents. In particular, the binuclear iron(III) complex 2′ we obtained by accident displayed a similar catalytic behavior compared to its iron(II) analogue complex 2.
Impacts of abiotic stresses on the physiology and metabolism of cool‐season grasses: A review
Authors: Loka Dimitra , Harper John , Humphreys Mike , Gasior Dagmara , Wootton-Beard Peter , Gwynn‐Jones Dylan , Scullion John , Doonan John , Kingston‐Smith Alison , Dodd Rosalind , Wang Jinyang , Chadwick David , Hill Paul , Jones Davey , Mills Gina , Hayes Felicity , Robinson David
Published: October 2018

Grasslands cover more than 70% of the world's agricultural land playing a pivotal role in global food security, economy, and ecology due to their flexibility and functionality. Climate change, characterized by changes in temperature and precipitation patterns, and by increased levels of greenhouse gases in the atmosphere, is anticipated to increase both the frequency and severity of extreme weather events, such as drought, heat waves, and flooding. Potentially, climate change could severely compromise future forage crop production and should be considered a direct threat to food security. This review aimed to summarize our current understanding of the physiological and metabolic responses of temperate grasses to those abiotic stresses associated with climate change. Primarily, substantial decreases in photosynthetic rates of cool‐season grasses occur as a result of high temperatures, water‐deficit or water‐excess, and elevated ozone, but not CO2 concentrations. Those decreases are usually attributed to stomatal and non‐stomatal limitations. Additionally, while membrane instability and reactive oxygen species production was a common feature of the abiotic stress response, total antioxidant capacity showed a stress‐specific response. Furthermore, climate change‐related stresses altered carbohydrate partitioning, with implications for biomass production. While water‐deficit stress, increased CO2, and ozone concentrations resulted in higher carbohydrate content, the opposite occurred under conditions of heat stress and flooding. The extent of damage is greatly dependent on location, as well as the type and intensity of stress. Fortunately, temperate forage grass species are highly heterogeneous. Consequently, through intra‐ and in particular inter‐specific plant hybridization (e.g., Festuca x Lolium hybrids) new opportunities are available to harness, within single genotypes, gene combinations capable of combating climate change.
Prevalence and predictors of undernutrition among underfive children in Arusha District, Tanzania
Authors: Kejo Dyness , Mosha Theobald C. E. , Petrucka Pammla , Martin Haikael , Kimanya Martin E.
Published: October 2018

Childhood undernutrition is a global health challenge impacting child growth and survival rates. This deficit in nutritional status contributes to the increasing chronic disease prevalence and economic burden in individuals and throughout developing contexts. A community‐based cross‐sectional study was conducted in Arusha District of Tanzania to determine the prevalence and predictors of undernutrition in 436 children. A structured questionnaire was used to collect data on demographic and socio‐economic factors as well as feeding practices and prevalence of preventable childhood diseases. Anthropometric data were collected through the measurement of length/height and weight of all children. The prevalence of undernutrition was estimated based on Z‐scores indices below −2SD of the reference population for weight for age (underweight), height for age (stunting), and weight for height (wasting). Fifty percent, 28%, and 16.5% of the children were stunted, underweight, and wasted, respectively. The age above 2 years and being a male were associated with stunting. The age above 2 years, nonexclusive breastfeeding children, and living at Seliani and Oturumeti were associated with being underweight. Similarly, morbidity, none exclusively breastfed children, living at Oturumeti, and being born to a mother 35 years and above were associated with wasting. In this study, we found the prevalence of child undernutrition in Arusha District is high in comparison with national and regional trends and appears to be associated with being a male. It is recommended that nutritionists and health planners should focus on these key predictors when planning nutrition interventions to address the problem of undernutrition among underfive children in Arusha District.
Nutritional composition and glycemic index analyses of vitamin A‐biofortified maize in healthy subjects
Authors: Oluba Olarewaju M. , Oredokun‐Lache Ajoke B.
Published: October 2018

Besides being a veritable tool for easing the problem of vitamin A deficiency (VAD), this study sought to explore another potential health benefit of vitamin A‐biofortified maize (VABM). In the present study, the nutritional composition and glycemic index (GI) of tuwo masara (a nonfermented maize‐based dumpling), made from VABM and the indigenous white maize (IWM) genotype, were evaluated. VABM showed significantly (p < 0.05) lower fat (4.38 ± 0.46%) and crude protein (6.58 ± 0.13%) but higher crude fiber (5.29 ± 0.0%) contents compared to 5.22 ± 0.25% crude fat, 7.28 ± 0.11% crude protein, and 4.69 ± 0.00% crude fiber in the IWM. The phytic acid content in the IWM (2.77 mg/100 g) was 39% higher than the level (2.0 ± 0.04 mg/100 g) in VABM. The major provitamin A carotenoid in the VABM were lutein (7.37 ± 0.52 μg/g), zeaxanthin (1.65 ± 0.01 μg/g), cryptoxanthin (1.29 ± 0.02 μg/g), and all‐trans‐β‐carotene (0.83 ± 0.02 μg/g), while the IWM contained only lutein (1.52 ± 0.32 μg/g). The total carotene concentration, 12.74 ± 1.13 μg/g dry weight in the VABM, was over eight times higher than that observed for the IWM, 1.52 ± 0.32 μg/g dry weight. The VABM tuwo masara showed a significantly lower GI value (70.3%) compared to the IWM tuwo masara (87.7%). Data obtained from the study further attest to the positive nutritional and health benefits of VABM.