bluuebunny/crossref_metadata_2025 huggingface dataset:
Unravelling the Enhanced High‐Temperature Performance of Lithium‐Rich Oxide Cathode with Methyl Diphenylphosphinite as Electrolyte Additive
Authors: Lou Shuaifeng , Ma Yulin , Zhou Zhenxin , Huo Hua , Zuo Pengjian , Cheng Xinqun , Qu Xiaohui , Gao Yunzhi , Du Chunyu , Yin Geping
Published: March 2018

Lithium‐rich oxide cathode materials with high energy density attract much attention, however, they tend to suffer from serious capacity fading during cycling, especially at elevated temperature. Here, methyl diphenylphosphinite (MDP) is studied as electrolyte additive for the first time to enhance the capacity retention of lithium‐rich oxide cathode during cycling under high temperature. As a result, the cyclic stability of Li1.16Ni0.2Co0.1Mn0.54O2 cathodes at elevated temperature is improved significantly when adopting 0.2 wt.% MDP, including an enhanced Columbic efficiency and capacity retention ratio promoted from 49.7 to 93.9 % after 80 cycles. Electrochemical and physical characterizations, combined with theoretical calculations, demonstrate that MDP tends to adsorb on the cathode surfacedue to the interaction between the P−O− species and transition‐metal elements, and then is oxidized preferentially at around 3.75 V (vs. Li/Li+), in situ forming a robust artificial interphase layer on the surface of the cathode. The interphases can effectively inhibit the electrolyte decomposition and greatly enhance the interface stability between Li1.16Ni0.2Co0.1Mn0.54O2 and the electrolyte at high voltage and high temperature.
An All Solid‐State Zinc−Air Battery with a Corrosion‐Resistant Air Electrode
Authors: Devendrachari Mruthyunjayachari Chattanahalli , Basappa Chidananda , Thimmappa Ravikumar , Bhat Zahid Manzoor , Kotresh Harish Makri Nimbegondi , Kottaichamy Alagar Raja , Varhade Swapnil , Khaire Siddhi , Reddy Kallam Ramareddy Venugopala , Thotiyl Musthafa Ottakam
Published: March 2018

We illustrate an all solid‐state Zn−air battery by utilizing the ability of a titanium‐nitride‐functionalized molecular catalyst to mediate the oxygen reduction reaction by avoiding the parasitic corrosion chemistry and the hydroxide‐holding capacity of the Zirfon membrane. The efficient ionic communication between the half‐cell electrodes provided by the Zirfon membrane in combination with the chemical/electrochemical stability of the TiN‐based air electrode ultimately led to an all solid‐state and air‐breathing battery possessing high durability and stability.
Flexible Versus Rigid G‐Quadruplex DNA Ligands: Synthesis of Two Series of Bis‐indole Derivatives and Comparison of Their Interactions with G‐Quadruplex DNA
Authors: Prasad Bagineni , Jamroskovic Jan , Bhowmik Sudipta , Kumar Rajendra , Romell Tajanena , Sabouri Nasim , Chorell Erik
Published: March 2018

Small molecules that target G‐quadruplex (G4) DNA structures are not only valuable to study G4 biology but also for their potential as therapeutics. This work centers around how different design features of small molecules can affect the interactions with G4 DNA structures, exemplified by the development of synthetic methods to bis‐indole scaffolds. Our synthesized series of bis‐indole scaffolds are structurally very similar but differ greatly in the flexibility of their core structures. The flexibility of the molecules proved to be an advantage compared to locking the compounds in the presumed bioactive G4 conformation. The flexible derivatives demonstrated similar or even improved G4 binding and stabilization in several orthogonal assays even though their entropic penalty of binding is higher. In addition, molecular dynamics simulations with the c‐MYC G4 structure showed that the flexible compounds adapt better to the surrounding. This was reflected by an increased number of both stacking and polar interactions with both the residues in the G4 DNA structure and the DNA residues just upstream of the G4 structure.
Synthesis of α‐Chlorolactams by Cyanoborohydride‐Mediated Radical Cyclization of Trichloroacetamides
Authors: Coussanes Guilhem , Jakobi Harald , Lindell Stephen , Bonjoch Josep
Published: March 2018

A cyanoborohydride‐promoted radical cyclization methodology has been developed to access α‐chlorolactams in a simple and efficient way using NaBH3CN and trichloroacetamides easily available from allylic and homoallylic secondary amines. This methodology allowed the synthesis of a library of α‐chlorolactams (mono‐ and bicyclic), which were tested for herbicidal activity, trans‐3‐chloro‐4‐methyl‐1‐(3‐trifluoromethyl)phenyl‐2‐pyrrolidinone being the most active.
Chemoenzymatic Synthesis of Asymmetrical Multi‐Antennary N‐Glycans to Dissect Glycan‐Mediated Interactions between Human Sperm and Oocytes
Authors: Chinoy Zoeisha S. , Friscourt Frédéric , Capicciotti Chantelle J. , Chiu Philip , Boons Geert‐Jan
Published: March 2018

Complex N‐glycans of glycoproteins of the zona pellucida (ZP) of human oocytes have been implicated in the binding of spermatozoa. The termini of these unusual bi‐, tri‐, and tetra‐antennary N‐glycans consist of the tetrasaccharide sialyl‐Lewisx (SLex), which was previously identified as the minimal epitope for sperm binding. We describe here the chemoenzymatic synthesis of highly complex triantennary N‐glycans derived from ZP carrying SLex moieties at the C‐2 and C‐2′ arm and a sialyl‐Lewisx‐Lewisx (SLex–Lex) residue at the C‐6 antenna and two closely related analogues. The compounds were examined for their ability to inhibit the interaction of human sperm to ZP. It was found that the SLex–Lex moiety is critical for inhibitory activity, whereas the other SLex moieties exerted minimal effect. Further studies with SLex–Lex and SLex showed that the extended structure is the more potent inhibitor. In addition, trivalent SLex–Lex and SLex were prepared which showed greater inhibitory activity compared to their monovalent counterparts. Our studies show that although SLex can inhibit the binding of spermatozoa, presenting this epitope in the context of a complex N‐glycan results in a loss of inhibitory potential, and in this context only SLex–Lex can make productive interactions. It is not the multivalent display of SLex on a multi‐antennary glycan but the presentation of multiple SLex–Lex on the various glycosylation sites of ZP that accounts for high avidity binding.
Trans‐Metal‐Trapping: Concealed Crossover Complexes En Route to Transmetallation?
Authors: Uzelac Marina , Mulvey Robert E.
Published: March 2018

Defined as the transfer of ligands from one metal to another, transmetallation is a common reaction in organometallic chemistry. Its chemical celebrity stems from its role in important catalytic cycles of cross‐coupling reactions such as those of Negishi, Sonogashira, Stille, or Suzuki. This article focuses on trans‐metal‐trapping (TMT), which could be construed as partially complete transmetallations. On mixing two distinct organometallic compounds, of for example lithium with aluminium or gallium, the two metals meet in a crossover co‐complex, but the reaction ceases at that point and full transmetallation is not reached. Though in its infancy, trans‐metal‐trapping shows promise in transforming failed lithiations into successful lithiations and in stabilising sensitive carbanions through cooperative bimetallic effects making them more amenable to onward reactivity.
Anion Recognition by a Bioactive Diureidodecalin Anionophore: Solid‐State, Solution, and Computational Studies
Authors: Jurček Ondřej , Valkenier Hennie , Puttreddy Rakesh , Novák Martin , Sparkes Hazel A. , Marek Radek , Rissanen Kari , Davis Anthony P.
Published: March 2018

Recent work has identified a bis‐(p‐nitrophenyl)ureidodecalin anion carrier as a promising candidate for biomedical applications, showing good activity for chloride transport in cells yet almost no cytotoxicity. To underpin further development of this and related compounds, a detailed structural and binding investigation is reported. Crystal structures of the transporter as five solvates confirm the diaxial positioning of urea groups while revealing a degree of conformational flexibility. Structures of complexes with Cl−, Br−, NO3−, SO42− and AcO−, supported by computational studies, show how the binding site can adapt to accommodate these anions. 1H NMR binding studies revealed exceptionally high affinities for anions in DMSO, decreasing in the order SO42−>H2PO4−≈HCO3−≈AcO−≫HSO4−>Cl−>Br−>NO3−>I−. Analysis of the binding results suggests that selectivity is determined mainly by the H‐bond acceptor strength of different anions, but is also modulated by receptor geometry.
Cell‐Penetrating Peptides Containing Fluorescent d‐Cysteines
Authors: Navo Claudio D. , Asín Alicia , Gómez‐Orte Eva , Gutiérrez‐Jiménez Marta I. , Compañón Ismael , Ezcurra Begoña , Avenoza Alberto , Busto Jesús H. , Corzana Francisco , Zurbano María M. , Jiménez‐Osés Gonzalo , Cabello Juan , Peregrina Jesús M.
Published: March 2018

A series of fluorescent d‐cysteines (Cys) has been synthesized and their optical properties were studied. The key synthetic step is the highly diastereoselective 1,4‐conjugate addition of aryl thiols to a chiral bicyclic dehydroalanine recently developed by our group. This reaction is fast at room temperature and proceeds with total chemo‐ and stereoselectivity. The Michael adducts were easily transformed into the corresponding amino acids to study their optical properties and, in some selected cases, into the corresponding N‐Fmoc‐d‐cysteine derivatives to be used in solid‐phase peptide synthesis (SPPS). To further demonstrate the utility of these non‐natural Cys‐derived fluorescent amino acids, the coumaryl and dansyl derivatives were incorporated into cell‐penetrating peptide sequences through standard SPPS and their optical properties were studied in different cell lines. The internalization of these fluorescent peptides was monitored by fluorescence microscopy.
Manganese‐Based Nanozymes: Multienzyme Redox Activity and Effect on the Nitric Oxide Produced by Endothelial Nitric Oxide Synthase
Authors: Singh Namrata , Geethika Motika , Eswarappa Sandeep M. , Mugesh Govindasamy
Published: March 2018

Nanomaterials having enzyme‐like activity (nanozymes) make them suitable candidates for various biomedical applications. In this study, we demonstrate the morphology‐dependent enzyme mimetic activity of Mn3O4 nanoparticles. It is found that Mn3O4 nanoparticles mimic the functions of all three cellular antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Interestingly, the nanozyme activity of Mn3O4 depends on various factors including size, morphology, surface area, and the redox properties of the metal ions. The Mn3O4 nanoflowers exhibited remarkably high activity in all three enzyme systems and the order of multienzyme activity of different morphologies was: flowers ≫ flakes > hexagonal plates≈polyhedrons≈cubes. Interestingly, all five nanoforms are taken up by the mammalian cells and were found to be biocompatible, with very low cytotoxicity. The activity of the most active nanoflowers was studied in primary human umbilical vein endothelial cells (HUVEC) and human pulmonary microvascular endothelial cells (hPMEC) and it was found that Mn3O4 does not reduce the level of nitric oxide (NO). This is in contrast to the effect of some of the Mn‐porphyrin‐based SOD mimetics, which are known to scavenge NO in endothelial cells.
Direct Electrochemistry of Bilirubin Oxidase from Magnaporthe orizae on Covalently‐Functionalized MWCNT for the Design of High‐Performance Oxygen‐Reducing Biocathodes
Authors: Gentil Solène , Carrière Marie , Cosnier Serge , Gounel Sébastien , Mano Nicolas , Le Goff Alan
Published: March 2018

Herein, the direct electrochemistry of bilirubin oxidase from Magnaporthe orizae (MoBOD) was studied on CNTs functionalized by electrografting several types of diazonium salts. The functionalization induces favorable or unfavorable orientation of MoBOD, the latter being compared to the well‐known BOD from Myrothecium verrucaria (MvBOD). On the same nanostructured electrodes, MoBOD can surpass MvBOD in terms of both current densities and minimal overpotentials. Added to the fact that MoBOD is also highly active at the gas‐diffusion electrode (GDE), these findings make MoBOD one of the MCOs with the highest catalytic activity towards the oxygen reduction reaction (ORR).
Enantio‐ and Diastereoselective Synthesis of Latanoprost using an Organocatalyst
Authors: Kawauchi Genki , Umemiya Shigenobu , Taniguchi Tohru , Monde Kenji , Hayashi Yujiro
Published: March 2018

An enantioselective total synthesis of latanoprost was achieved. Its chiral cyclopentane core structure was constructed through an organocatalyst‐mediated [3+2]‐cycloaddition reaction, and chirality in the ω‐side chain was generated by prolinate‐anion‐mediated α‐aminoxylation of an aldehyde. Highly diastereoselective domino acetalization and an oxy‐Michael reaction were key steps for the generation of C9 chirality.
Light‐Controlled Simultaneous “On Demand” Release of Cytotoxic Combinations for Bimodal Killing of Cancer Cells
Authors: Tessaro André Luiz , Fraix Aurore , Failla Mariacristina , Cardile Venera , Graziano Adriana C. E. , Estevão Bianca Martins , Rescifina Antonio , Sortino Salvatore
Published: March 2018

In this contribution, we report a novel entirely photocontrolled nanoplatform comprising a binary mixture of pluronic copolymers capable of self‐assembling into core–shell micelles and co‐entrapping two photoactivatable components: a benzoporphyrin photosensitizer for photodynamic therapy (PDT) and coumarin‐photocaged chemotherapeutic agent Chlorambucil (CAB). The resulting supramolecular micellar assembly is about 30 nm in diameter with a polydispersity index <0.1, stable for more than 72 h, and exhibits excellent preservation of the photochemical properties of the two photoresponsive components, even though they are confined within the same host nanocarrier. Appropriate regulation of the relative concentrations of these components makes them capable of absorbing visible light in comparable amounts, leading to effective simultaneous photogeneration of singlet oxygen and photo‐triggered release of CAB. This “on demand” release of cytotoxic combinations results in amplified anticancer activity against MCF‐7 human breast adenocarcinoma cells.
Pathway Diversity Leads to 2D‐Nanostructure in Photo‐triggered Supramolecular Assembly
Authors: Pal Deep Sankar , Ghosh Suhrit
Published: March 2018

This Communication reports photo‐triggered supramolecular assembly of a naphthalene‐diimide (NDI) derivative, appended with a photo‐labile ortho‐nitrobenzyl (ONB)‐ester protected carboxylic acid. Photo‐irradiation produces the free COOH group which facilitates H‐bonding‐driven face‐to‐face stacking of the NDI chromophores producing an ultra‐thin (height <2.0 nm) two‐dimensional (2D) nanosheet. In contrast, spontaneous supramolecular assembly of the same active monomer exhibits entirely different features such as uncontrolled growth, J‐aggregation and fibrillar morphology. A completely different pathway for photo‐triggered assembly is attributed to the dual function of the photo‐caged pro‐monomer in i) producing the carboxylic acid in controlled manner and ii) simultaneously inhibiting the spontaneous J‐aggregation of the photo‐generated monomers by ester‐carboxylic acid H‐bonding and in turn directing a distinct growth mechanism.
Regioisomeric Tandem Triblock Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxanes
Authors: Shao Yu , Yin Hang , Jin Peng‐Fei , Jiang Yu‐Sheng , Yang Shuguang , Zhang Wen‐Bin
Published: March 2018

We report the design, synthesis and self‐assembly of a series of tandem triblock shape amphiphile regioisomers composed of one rod‐like fluorinated polyhedral oligomeric silsesquioxane (FPOSS) cage tethered with two spherical tert‐butyl‐POSS (tBPOSS) cages in para‐, meta‐, and ortho‐configurations. Precision syntheses are achieved through sequential “click” reactions and the compounds are thoroughly characterized by combined techniques of NMR, FT‐IR and MALDI‐TOF MS spectroscopy. Only the ortho‐isomer forms an ordered lamellae structure induced by the crystallization of perfluoroalkyl‐chains and the other two remain amorphous due to frustrated packing by unfavorable regio‐configuration. The distinct assembly behaviors of these three regioisomers reflect the delicate influence of a minute structural difference on precision macromolecular assembly.
Deciphering the Mechanism of Human Carbonic Anhydrases Inhibition with Sulfocoumarins: Computational and Experimental Studies
Authors: Nocentini Alessio , Carta Fabrizio , Tanc Muhammet , Selleri Silvia , Supuran Claudiu T. , Bazzicalupi Carla , Gratteri Paola
Published: March 2018

The reaction mechanism of the carbonic anhydrase‐mediated hydrolysis of sulfocoumarins to sulfonic acids has been investigated on an enzyme cluster model using the B3LYP hybrid density functional theory (DFT) and the QST procedure for the Transition State (TS) search. A multistep process was highlighted, with the rate‐determining step identified in the initial dual nucleophilic/acidic attack of the zinc‐bound hydroxide ion to the sulfocoumarin sulfur atom and to the C3=C4 double bond. The reported multi‐step process, combined to SAR analysis on a new set of derivatives, highlighted unprecedented mechanistic aspects of the CA‐mediated prodrug activation, which in turn possess relevant consequences to the isoforms‐selective inhibition profiles reported by such a class of compounds.
Chemically Tunable Formation of Different Discrete, Oligomeric, and Polymeric Self‐Assembled Structures from Digold Metallotweezers
Authors: Ibáñez Susana , Peris Eduardo
Published: March 2018

Digold metallotweezers whose complex supramolecular landscape is controlled by adding a series of metal cations are described. The metallotweezers have a strong tendency to form interesting supramolecular structures on addition of Tl+, Ag+, and Cu+. The choice of the cation can be used to direct the formation of a designated molecular architecture. The addition of thallium facilitates the formation of a self‐aggregated duplex structure in which the cation occupies the cavity of the dimer. The same type of structure is formed when Cu+ is added, and the resulting duplex inclusion complex shows interesting vapochromic properties. This copper‐encapsulating system evolves in solution to a 1D helical supramolecular polymer showing multiple aurophilic and Au⋅⋅⋅Cu interactions, in which the copper cation is bound to several alkynyl ligands of the tweezer. The addition of a small amount of silver cations to the digold tweezer yields a similar type of inclusion dimer complex, but adding an excess of the cation produces new discrete molecules presumably exhibiting multiple Au⋅⋅⋅Au, Au⋅⋅⋅Ag, and Ag⋅⋅⋅Ag metallophilic interactions. The differences in the supramolecular structures formed are ascribed to the different tendencies of the metal cations to exhibit interactions with the gold atoms and to coordinate to the alkynyl ligands of the tweezer.
Synthesis of Highly Substituted 1,2‐Diazetidin‐3‐ones, Small‐Ring Scaffolds for Drug Discovery
Authors: Santos Marilia S. , Nortcliffe Andrew , Lewis William , Bradshaw Tracey D. , Moody Christopher J.
Published: March 2018

1,2‐Diazetidin‐3‐ones are readily accessible, small ring scaffolds that upon functionalization have the potential to produce diverse 3‐dimensional structures for drug discovery. Thus, treatment of diazo hydrazides, obtained from simple hydrazides and malonyl half ester derivatives, followed by diazo transfer, with catalytic amounts of rhodium(II) acetate dimer results in intramolecular carbenoid N−H insertion to give 1,2‐diazetidin‐3‐ones. Although subsequent functionalization reactions could be hampered by the lability of the 4‐membered ring, a wide range of new derivatives was available by deprotection at N‐1, and subsequent amide or urea formation. The structures of four four‐membered rings was confirmed by X‐ray crystallography; the compounds showed modest growth inhibitory activity in mammary carcinoma cells.
34S: A New Opportunity for the Efficient Synthesis of Stable Isotope Labeled Compounds
Authors: Ren Sumei , Fier Patrick S. , Ren Hong , Hoover Andrew J. , Hesk David , Marques Rosemary , Mergelsberg Ingrid
Published: March 2018

The synthesis of stable isotope labeled (SIL) complex drug molecules with a ≥3 mass unit increase from the parent compound is essential for drug discovery and development. Typical approaches that rely on 2H, 13C, and 15N isotopes can be very challenging or even intractable, and can delay the drug development process. This work introduces a new concept for the synthesis of labeled compounds that relies on the use of 34S. The synthetic utility of 34S was demonstrated with the efficient synthesis of [34S]phosphorothioates [34S2]‐PS‐ODNs‐TTT and [13C, 15N, 34S]‐ceftolozane. In addition, a procedure for the direct oxidation of phosphites to [34S]phosphorothioates using elemental 34S without isotope dilution was developed.
A Versatile Colorimetric Probe based on Thiosemicarbazide–Amine Proton Transfer
Authors: Calvino Céline , Piechowicz Marek , Rowan Stuart J. , Schrettl Stephen , Weder Christoph
Published: March 2018

There is significant interest in the rapid and efficient detection of amines, which are widely used in different industries and also serve as markers in many biological processes. This work reports that the coupling of a thiosemicarbazide binding motif and a naphthalimide‐based chromophore affords highly sensitive sensor molecules, which can indicate the presence of amines with a pronounced and readily visible color change. It was demonstrated that the binding mechanism involves a proton transfer from the thiosemicarbazide to the analyte. This process renders the mechanism highly sensitive and broadly exploitable. The potential usefulness of the sensor is demonstrated by fabricating an indicator paper, which allows for the detection of volatile amines at concentrations as low as ca. 10 ppm.
Dismantling‐Free and Gentle Mechanical Cleaning of Industrial Heat Exchangers and Cooling Circuits
Authors: Kuschnerow Jan , Klein Norbert , Schlüter Florian , Augustin Wolfgang , Scholl Stephan , Strathmann Martin , Schaule Gabriela , Hammann Hans‐Gerd
Published: March 2018

Das COMPREX®‐Verfahren ist ein geeignetes mechanisches Reinigungsverfahren für Rohrleitungen und Wärmeübertrager. Impulsweise zu laminar einfließendem Wasser dosierte Druckluft erzeugt Luft‐ und Wasserblöcke, die sich in großer Geschwindigkeit durch die Anlage bewegen. Es arbeitet ohne Demontage der Apparate und ermöglicht kurze Stillstandszeiten. Es erfordert keinen Einsatz von Chemikalien und ist materialschonend. Mobile Technikeinheiten ermöglichen den Einsatz an beliebigen Standorten. Gegenüber anderen Verfahren erlaubt es kürzere Reinigungszyklen und dadurch eine höhere Verfügbarkeit der Anlage.
Close‐to‐Practice Investigations of Heterogeneously Catalyzed Syngas Conversions in Slurry and Fixed‐Bed Reactor Systems
Authors: Girod Kai , Breitkreuz Klaas , Gerstner Andrea , Marzi Thomas , Schulzke Tim , Kaluza Stefan
Published: March 2018

In der Grundlagenforschung wird die Testung heterogener Katalysatoren normalerweise mit sehr kleinen Probenmengen durchgeführt. Eine Übertragung der ermittelten Ergebnisse hinsichtlich Produktivität und Standzeit auf den technischen Maßstab ist nur sehr eingeschränkt möglich. Es wurde ein neues praxisnahes Testsystem für heterogene Katalysatoren entwickelt. Es kann sowohl in Festbett‐Fahrweise als auch in Slurry‐Fahrweise in einem weiten Temperatur‐ und Druckbereich betrieben werden. Das System wurde für die Synthese höherer Alkohole und die einstufige Dimethylether‐Synthese erfolgreich eingesetzt.
Catalyst Deactivation During Photocatalytic Degradation of Methylene Blue with TiO2
Authors: Robert Johannes , Jüstel Thomas , Ulber Roland , Jordan Volkmar
Published: March 2018

Neben hohen Umsatzraten ist die Langlebigkeit eines Katalysators von entscheidender Bedeutung. Im Rahmen des photochemischen Abbaus von Methylenblau an aktiviertem TiO2 entsteht CO2, das mit Ca2+ und Mg2+ im alkalischen unlösliche Carbonatsalze bildet, die ihrerseits Verkrustungen auf der Katalysatoroberfläche erzeugen und den Reaktanden dadurch den Zugang zu den aktiven Zentren verwehren. Durch den Vergleich des beobachtbaren Reaktionskoeffizienten erster Ordnung bei unterschiedlichen pH‐Werten konnte gezeigt werden, dass es sich um einen Dual‐site‐Mechanismus handelt. Durch EDX‐Elementmapping konnte gezeigt werden, dass die Verringerung der Reaktionsgeschwindigkeiten mit wiederverwendetem Katalysator in CaCl2‐ und MgCl2‐Lösungen durch Verkrustungen der Erdalkalimetallcarbonate hervorgerufen wird.
Additive Manufacturing of Al2O3‐Based Carriers for Heterogeneous Catalysis
Authors: Ludwig Theresa , von Seckendorff Jennie , Troll Carsten , Fischer Richard , Tonigold Markus , Rieger Bernhard , Hinrichsen Olaf
Published: March 2018

Additive manufacturing techniques are known for their impressive possibilities in shaping complex structures, which would be beneficial in the production of alumina‐based catalyst shaped bodies. 3D printing of dense ceramics, especially Al2O3, is known for various printing systems. However, only little effort was done to produce pure alumina parts with increased BET surface areas and sufficient mechanical strength to be used as catalyst carriers. The applicability of four different printing techniques is evaluated and discussed to determine possibilities, strategies and limitations of each technique.
Mixing in an agitated tubular reactor
Authors: Derksen Jos J.
Published: March 2018

We analyze, through numerical simulations, the single‐phase liquid flow and associated passive scalar mixing in a tubular reactor that is agitated by lateral shaking, which induces the motion of a solid mixing element inside the reactor. The Reynolds number associated with the shaking motion is in the range 1200–5600. Dependent on its specific value, we perform direct or large eddy simulations. A fixed‐grid lattice‐Boltzmann method is used for solving the fluid flow. The moving boundary condition at the surface of the mixing element is dealt with by means of an immersed boundary method. To quantify mixing, a transport equation for a passive scalar is solved in conjunction with the flow dynamics.
A comprehensive decoupling control strategy for a gas flow facility based on active disturbance rejection generalized predictive control
Authors: Wu Xia , Chen Zengqiang , Zhao Yue , Sun Lijun , Sun Mingwei
Published: March 2018

A comprehensive decoupling control (CDC) method, based on the active disturbance rejection generalized predictive control (ADRC‐GPC) technology, is proposed in this paper for square multi‐input multi‐output (MIMO) systems. The central idea of this approach is that the total disturbance, which includes the partial coupling information among loops, the internal uncertainties, and the external disturbance, can be estimated by output through the extended state observer (ESO) and compensated in the feedback loop by feedback control law. Such estimating and cancelling can readily decouple the primal coupling system into multiple single‐input single output (SISO) subsystems with the form of cascade integrators. Then the generalized predictive controller is designed for each subsystem. The proposed design is effectively used in the gas flow facility. Mathematical simulations and experiments show that compared with the proportional integral derivative (PID) method, the ADRC‐GPC controller can achieve better dynamic performance, decoupling ability, disturbance rejection capability, and performance robustness.
Preparation of a novel magnetically recoverable copper complex catalyst and its application in the Henry reaction
Authors: Yang Bing , Sun Meiyu , Qian Xiangli , Gao Hongfen , Ding Xia , Zhang Qikun
Published: March 2018

A novel magnetically recoverable copper complex catalyst based on Fe3O4 nanoparticles as a magnetic carrier was successfully synthesized. The catalyst was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and alternating gradient magnetometry (AGM). The Henry reaction catalyzed by this prepared magnetically recoverable copper complex catalyst proceeded in high yield (97 %) and with high conversion (94 %). The prepared catalyst possesses superparamagnetic properties and can be recycled very conveniently using an external magnetic field. The self‐prepared catalyst has excellent catalytic selectivity and good reusability, making this method a clean and energy‐efficient process.
Non‐Oxidative Methane Conversion Using Lead‐ and Iron‐Modified Albite Catalysts in Fixed‐Bed Reactor
Authors: Chen Ye , Wang Xin , Luo Xuegang , Lin Xiaoyan , Zhang Yu
Published: March 2018

Raw and modified albite catalysts, including Pb/Albite and Fe/Albite catalysts, have been investigated for methane conversion to C2 hydrocarbons under non‐oxidative conditions. Introduction of Pb to albite improved the activity and selectivity to non‐coke products. Based on characterization, it was found that Pb entered into the alkali and alkaline‐earth metal sites of albite, while partial Fe doped in the tetrahedron sites and the other loaded on the surface of albite. At the reaction temperature of 1073 K, methane gas hourly space velocity (GHSV) of 2 L·gcat–1·h–1, catalyst dosage of 0.25 g (300 mesh), the methane conversion catalyzed by raw albite in the fixed‐bed micro reactor exhibited a methane conversion of 3.32%. Notably, introducing a Pb content of 3.4 wt% into albite greatly enhanced the conversion of methane up to 8.19%, and the selectivity of C2 hydrocarbons reached 99% without any coke under the same reaction conditions. While Fe‐doping could weakly heighten the methane conversion to 3.97%, and coke was formed. Thus, a comparison of Pb/Albite and Fe/Albite catalysts demonstrates that the catalytic activity of albite is mainly decided by alkali and alkaline‐earth metal sites, and lead‐modification can effectively improve the catalytic activity of albite.
Isolable Radical Ions of Main‐Group Elements: Structures, Bonding and Properties
Authors: Tan Gengwen , Wang Xinping
Published: March 2018

Synthesis of stable main‐group element‐based radicals represents one of the most interesting topics in contemporary organometallic chemistry, because of their vital roles in organic, inorganic and biological chemistry as well as materials science. However, the access of stable main‐group element‐based radicals is highly challenging owing to the lack of energetically accessible orbitals in the main‐group elements. During the last decades, several synthetic strategies have been developed in obtaining these reactive species. Among them, utilizing the sterically demanding substituents and π‐conjugated ligands has proven to be an effective approach. Weakly coordinating ions (WCAs) have also been found to be exceptionally practical in synthesizing radical cations of main‐group elements. By introducing these stabilization methods, we have successfully prepared a variety of radical ions of p‐block elements in the crystalline forms, and investigated their properties by different experimental and quantum chemical calculation methods. According to the investigations, magnetic stability was observed, resulting from the intramolecular electron‐exchange interaction. Furthermore, we also found that the singlet‐triplet energy gaps of the bis(triarylamine) diradical dications can be tunable by varying the temperature. These investigations open new avenues of the main‐group element‐based radicals for a large variety of applications.
Silaindacenodithiophene‐Based Fused‐Ring Non‐Fullerene Electron Acceptor for Efficient Polymer Solar Cells
Authors: Nian Yaowen , Wang Zhen , Jiang Haiying , Feng Shizhen , Li Suhan , Zhang Lianjie , Cao Yong , Chen Junwu
Published: March 2018

In this work, a new A‐D‐A type nonfullerene small molecular acceptor SiIDT‐IC, with a fused‐ring silaindacenodithiophene (SiIDT) as D unit and 2‐(3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (INCN) as the end A unit, was design and synthesized. The SiIDT‐IC film shows absorption peak and edge at 695 and 733 nm, respectively. The HOMO and LUMO of SiIDT‐IC are of −5.47 and −3.78 eV, respectively. Compared with carbon‐bridging, the Si‐bridging can result in an upper‐lying LUMO level of an acceptor, which is benefit to achieve a higher open‐circuit voltage in polymer solar cells (PSCs). Complementary absorption and suitable energy level alignment between SiIDT‐IC and wide bandgap polymer donor PBDB‐T were found. For the PBDB‐T:SiIDT‐IC based inverted PSCs, a D/A ratio of 1: 1 was optimal to achieve a power conversion efficiency (PCE) of 7.27%. With thermal annealing (TA) of the blend film, a higher PCE of 8.16% could be realized due to increasing of both short‐circuit current density and fill factor. After the TA treatment, hole and electron mobilities were elevated to 3.42 × 10−4 and 1.02 × 10−4 cm2·V−1·s−1, respectively. The results suggest that the SiIDT, a Si‐bridged fused ring, is a valuable D unit to construct efficient nonfullerene acceptors for PSCs.
Critical Role of Molecular Electrostatic Potential on Charge Generation in Organic Solar Cells
Authors: Yao Huifeng , Qian Deping , Zhang Hao , Qin Yunpeng , Xu Bowei , Cui Yong , Yu Runnan , Gao Feng , Hou Jianhui
Published: March 2018

Revealing the charge generation is a crucial step to understand the organic photovoltaics. Recent development in non‐fullerene organic solar cells (OSCs) indicates efficient charge separation even with negligible energetic offset between the donor and acceptor materials. These new findings trigger a critical question concerning the charge separation mechanism in OSCs, traditionally believed to result from sufficient energetic offset between the polymer donor and fullerene acceptor. We propose a new mechanism, which involves the molecular electrostatic potential, to explain efficient charge separation in non‐fullerene OSCs. Together with the new mechanism, we demonstrate a record efficiency of ~12% for systems with negligible energetic offset between donor and acceptor materials. Our analysis also rationalizes different requirement of the energetic offset between fullerene‐based and non‐fullerene OSCs, and paves the way for further design of OSC materials with both high photocurrent and high photovoltage at the same time.
Effect of Fluorination on the Photovoltaic Properties of Medium Bandgap Polymers for Polymer Solar Cells
Authors: Guo Huan , Li Wanbin , Chang Chunmei , Guo Xia , Zhang Maojie
Published: March 2018

Fluorination of conjugated polymers is one of the effective strategies to tune the molecular energy levels and morphology for high efficient polymer solar cells (PSCs). Herein, two novel donor‐acceptor conjugated polymers, PffBT and PBT, based on bis(3,5‐bis(hexyloxy)phenyl)benzo[1,2‐ b:4,5‐b']dithiophene and benzo[c][1,2,5]thiadiazole (BT) with or without fluorination, respectively, were synthesized, and their photovoltaic properties were compared. The polymer PffBT based on fluorinated BT showed lower frontier energy levels, improved polymer ordering, and a well‐developed fibril structure in the blend with PC71BM. As a result, the PSCs based on PffBT/PC71BM exhibit a superior power conversion efficiency (PCE) of 8.6% versus 4.4% for PBT‐based devices, due to a high space charge limit current (SCLC) hole mobility, mixed orientation of polymer crystals in the active layer, and low bimolecular recombination.
Sole and combined vitamin C supplementation can prevent postoperative atrial fibrillation after cardiac surgery: A systematic review and meta‐analysis of randomized controlled trials
Authors: Shi Rui , Li Zhen‐Han , Chen Dan , Wu Qing‐Chen , Zhou Xiao‐Li , Tie Hong‐Tao
Published: March 2018

We undertook a systematic review and meta‐analysis to evaluate the effect of vitamin C supplementation (vitamin C solely or as adjunct to other therapy) on prevention of postoperative atrial fibrillation (POAF) in patients after cardiac surgery. PubMed, Embase, Web of Science, and Cochrane Library were systematically searched to identify randomized controlled trials assessing the effect of vitamin C supplementation in adult patients undergoing cardiac surgery, and the meta‐analysis was performed with a random‐effects model. Thirteen trials involving 1956 patients were included. Pooling estimate showed a significantly reduced incidence of POAF (relative risk [RR]: 0.68, 95% confidence interval [CI]: 0.54 to 0.87, P = 0.002) both in vitamin C alone (RR: 0.75, 95% CI: 0.63 to 0.90, P = 0.002) and as an adjunct to other therapy (RR: 0.32, 95% CI: 0.20 to 0.53, P < 0.001). The results remain stable and robust in subgroup and sensitivity analyses, and trial sequential analysis also confirmed that the evidence was sufficient and conclusive. Additionally, vitamin C could significantly decrease intensive care unit length of stay (weighted mean difference: −0.24 days, 95% CI: –0.45 to −0.03, P = 0.023), hospital length of stay (weighted mean difference: −0.95 days, 95% CI: –1.64 to −0.26, P = 0.007), and risk of adverse events (RR: 0.45, 95% CI: 0.21 to 0.96, P = 0.039). Use of vitamin C alone and as adjunct to other therapy can prevent POAF in patients undergoing cardiac surgery and should be recommended for patients receiving cardiac surgery for prevention of POAF.
Association between B‐type natriuretic peptide and within‐visit blood pressure variability
Authors: Rodrigues Ana Beatriz , Gismondi Ronaldo Altenburg , Lagoeiro Antonio , Cecilio Angela Mendes , Vasques Delvo , Arita Rafael , Folegatti Thabata , Rosa Maria Luiza
Published: March 2018

Background

Blood pressure variability (BPV) has been shown to predict cardiovascular events. Within‐visit BPV is the simplest and easiest measure of BPV, but previous studies have shown conflicts as to whether within‐visit BPV correlates with target organ damage. We aimed to evaluate whether within‐visit BPV correlates with B‐type natriuretic peptide (BNP) in a general population.

Hypothesis

Within‐visit BPV correlates with BNP in a general population.

Methods

This was a cross‐sectional study that included 633 individuals, randomly selected, age 45 to 99 years, registered in the primary care program from an urban medium‐sized town. Patients were scheduled for a single‐day visit that consisted of clinical evaluation and laboratory tests. Three blood pressure (BP) readings, 1 minute apart, were done, and within‐visit BPV was determined as the coefficient of variation (CV) of the 3 BP measures. Our main outcome was to correlate BNP and within‐visit BPV. A multivariable model was estimated using a generalized linear model to evaluate the independent effects of different variables on BNP levels.

Results

The median age was 57 years. Median BNP was 16 pg/mL, and the median systolic and diastolic BP‐CV were, respectively, 3.9% and 3.5%. There was a weak but positive correlation between BNP and both systolic BP‐CV and diastolic BP‐CV (r = 0.107 and P = 0.007 and r = 0.092 and P = 0.019, respectively). In multiple regression equation, systolic BP, diastolic BP‐CV, body mass index, and estimated glomerular filtration rate were associated with BNP.

Conclusions

In the present study, there was a positive, albeit weak, correlation between within‐visit BPV and BNP. In addition, diastolic BPV was associated with BNP even after adjustment for multiple confounders.
Serum albumin concentration as an independent prognostic indicator in patients with pulmonary arterial hypertension
Authors: Snipelisky David , Jentzer Jacob , Batal Omar , Dardari Zeina , Mathier Michael
Published: March 2018

Background

Serum albumin is a strong prognostic indicator for many disease processes, yet limited data exist regarding its prognostic relationship in pulmonary arterial hypertension (PAH). Our study aims to assess the relationship of hypoalbuminemia with disease severity and mortality in this population.

Hypothesis

Serum albumin concentrations are a predictor of outcomes in PAH.

Methods

A retrospective review of all patients with World Health Organization group 1 PAH evaluated between March 2001 and August 2008 was performed. Patients were stratified into groups based on serum albumin concentration ≤3.3 g/dL (hypoalbuminemia) vs >3.3 g/dL. Clinical, hemodynamic, and survival comparisons were compared between groups using Student t test and χ2 test, followed by univariate analysis and multivariate logistic regression.

Results

A total of 163/273 (59.7%) patients had a documented serum albumin concentration. Hypoalbuminemia was present in 41 (25.2%) patients and serum albumin ≤3.3 g/dL represented the lowest quartile of serum albumin. Patients with hypoalbuminemia had higher rates of renal dysfunction (26.8% vs 9.8%, P =0.0069) and hepatic dysfunction (29.3% vs 6.6%, P <0.001), and lower hemoglobin levels (11.6 vs 13.4 g/dL, P < 0.001). Hemodynamic and functional capacity assessments were comparable between groups. Independent predictors of mortality included low albumin levels (hazard ratio [HR]: 0.485, P = 0.008), high right atrial systolic area (HR: 1.062, P = 0.003), low Fick‐derived cardiac index (HR: 1.465, P = 0.016), and high New York Heart Association functional class (HR: 1.767, P = 0.042). Patients with hypoalbuminemia demonstrated a significantly lower survival rate at latest follow‐up (P = 0.01).

Conclusions

Lower serum albumin concentrations in patients with PAH are associated with higher mortality and can serve as a marker of disease severity in this patient population.
Carboxylate Analogues of Aryl‐Urea‐Substituted Fatty Acids That Target the Mitochondria in MDA‐MB‐231 Breast Cancer Cells to Promote Cell Death
Authors: Koolaji Nooshin , Rawling Tristan , Bourget Kirsi , Murray Michael
Published: March 2018

Selective targeting of the tumor cell mitochondrion is a viable approach for the development of anticancer agents because the organelle is functionally different from the mitochondria of normal cells. We recently developed a novel aryl‐urea fatty acid, 16({[4‐chloro‐3‐(trifluoromethyl)phenyl]carbamoyl}amino)hexadecanoic acid (1) that was found to disrupt mitochondria and to activate apoptosis in MDA‐MB‐231 breast cancer cells. However, there is currently little information on the structural requirements for the activity of compound 1 analogues. The present study evaluated the role of the carboxylic acid group on the anticancer activity of 1. Bioisosteric replacement of the carboxylate in 1 maintained activity. Thus, like 1, the sulfonic acid analogue 1‐SA and the oxo‐thiadiazole analogue 1‐OT were also found to target the mitochondrion and to activate cell killing capacity. The hydroxamic acid analogue 1‐HA also killed MDA‐MB‐231 cells, but its onset of action was slower than that of 1‐SA and 1‐OT. In contrast, replacement of the carboxylate with non‐bioisosteric amido and methylamido groups produced analogues that minimally altered mitochondrial function and showed little capacity to decrease tumor cell viability. These findings suggest that the carboxylate moiety in the novel mitochondrially targeted agent 1 is an important determinant of the kinetics and efficacy of anticancer cell activities of compound 1 analogues. Further development of carboxylate‐modified analogues of aryl‐urea fatty acids as potential anticancer agents could now be warranted.
Niclosamide, a Drug with Many (Re)purposes
Authors: Kadri Hachemi , Lambourne Olivia A. , Mehellou Youcef
Published: March 2018

Niclosamide is an anthelmintic drug that has been used for over 50 years mainly to treat tapeworm infections. However, with the increase in drug repurposing initiatives, niclosamide has emerged as a true hit in many screens against various diseases. Indeed, from being an anthelmintic drug, it has now shown potential in treating Parkinson's disease, diabetes, viral and microbial infections, as well as various cancers. Such diverse pharmacological activities are a result of niclosamide's ability to uncouple mitochondrial phosphorylation and modulate a selection of signaling pathways, such as Wnt/β‐catenin, mTOR and JAK/STAT3, which are implicated in many diseases. In this highlight, we discuss the plethora of diseases that niclosamide has shown promise in treating.
Skeletal Optimization of Cytotoxic Lipidic Dialkynylcarbinols
Authors: Bourkhis Maroua , Gaspard Hafida , Rullière Pauline , de Almeida Diana K. C. , Listunov Dymytrii , Joly Etienne , Abderrahim Raoudha , de Mattos Marcos C. , de Oliveira Maria C. F. , Maraval Valérie , Chauvin Remi , Génisson Yves
Published: March 2018

In line with a recent study of the pharmacological potential of bioinspired synthetic acetylenic lipids, after identification of the terminal dialkynylcarbinol (DAC) and butadiynyl alkynylcarbinol (BAC) moieties as functional antitumor pharmacophoric units, this work specifically addresses the issue of carbon backbone length. A systematic variation of the aliphatic chain length was thus carried out in both the DAC and BAC series. The critical impact of the length of the lipidic skeleton was first confirmed in the racemic series, with the highest cytotoxic activity observed for C17 to C18 backbones. Enantiomerically enriched samples were prepared by asymmetric synthesis of the optimal C18 DAC and C17 BAC derivatives. Samples with upgraded enantiomeric purity were alternatively produced by enzymatic kinetic resolution. Eutomers possessing the S configuration displayed cytotoxicity IC50 values as low as 15 nm against HCT116 cancer cells, the highest level of activity reached to date in this series.
The Current Status of O‐Heterocycles: A Synthetic and Medicinal Overview
Authors: Singh Pankaj Kumar , Silakari Om
Published: March 2018

O‐Heterocycles have been explored in the field of medicinal chemistry for a long time, but their significance has not been duly recognised and they are often shunned in favour of N‐heterocycles. The design of bioactive molecules for nearly every pathophysiological condition is primarily focused on novel N‐heterocycles. The main reasons for such bias include the ease of synthesis and possible mimicking of physiological molecules by N‐heterocycles. But considering only this criterion rarely provides breakthrough molecules for a given disease condition, and instead the risks of toxicity or side effects are increased with such molecules. On the other hand, owing to improved synthetic feasibility, O‐heterocycles have established themselves as equally potent lead molecules for a wide range of pathophysiological conditions. In the last decade there have been hundreds of reports validating the fact that equally potent molecules can be designed and developed by using O‐heterocycles, and these are also expected to have comparably low toxicity. Even so, researchers tend to remain biased toward the use of N‐heterocycles over O‐heterocycles. Thus, this review provides a critical analysis of the synthesis and medicinal attributes of O‐heterocycles, such as pyrones, oxazolones, furanones, oxetanes, oxazolidinones, and dioxolonones, and others, reported in the last five years, underlining the need for and the advantages guiding researchers toward them.