bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen Exchange Processes between Oxide Memristive Devices and Water Molecules
Authors: Heisig Thomas , Baeumer Christoph , Gries Ute N. , Mueller Michael P. , La Torre Camilla , Luebben Michael , Raab Nicolas , Du Hongchu , Menzel Stephan , Mueller David N. , Jia Chun‐Lin , Mayer Joachim , Waser Rainer , Valov Ilia , De Souza Roger A. , Dittmann Regina
Published: June 2018

Resistive switching based on transition metal oxide memristive devices is suspected to be caused by the electric‐field‐driven motion and internal redistribution of oxygen vacancies. Deriving the detailed mechanistic picture of the switching process is complicated, however, by the frequently observed influence of the surrounding atmosphere. Specifically, the presence or absence of water vapor in the atmosphere has a strong impact on the switching properties, but the redox reactions between water and the active layer have yet to be clarified. To investigate the role of oxygen and water species during resistive switching in greater detail, isotope labeling experiments in a N2/H218O tracer gas atmosphere combined with time‐of‐flight secondary‐ion mass spectrometry are used. It is explicitly demonstrated that during the RESET operation in resistive switching SrTiO3‐based memristive devices, oxygen is incorporated directly from water molecules or oxygen molecules into the active layer. In humid atmospheres, the reaction pathway via water molecules predominates. These findings clearly resolve the role of humidity as both oxidizing agent and source of protonic defects during the RESET operation.
A Bezel‐Less Tetrahedral Image Sensor Formed by Solvent‐Assisted Plasticization and Transformation of an Acrylonitrile Butadiene Styrene Framework
Authors: Jang Hun Soo , Kim Gi‐Gwan , Kang Seong Hyeon , Kim Yeongmin , Yoo Jung Il , Yoo Seonggwang , Kim Kun‐Kook , Jung Changsoo , Ko Heung Cho
Published: June 2018

A method for transforming planar electronic devices into 3D structures under mechanically mild and stable conditions is demonstrated. This strategy involves diffusion control of acetone as a plasticizer into a spatially designed acrylonitrile butadiene styrene (ABS) framework to both laminate membrane‐type electronic devices and transform them into a desired 3D shape. Optical, mechanical, and electrical analysis reveals that the plasticized region serves as a damper and even reflows to release the stress of fragile elements, for example, an Au interconnect electrode in this study, below the ultimate stress point. This method also gives considerable freedom in aligning electronic devices not only in the neutral mechanical plane of the ABS framework, which is the general approach in flexible electronics, but also to the top surface, without inducing electrical failure. Finally, to develop a prototype omnidirectional optical system with minimal aberrations, this method is used to produce a bezel‐less tetrahedral image sensor.
From Wood to Textiles: Top‐Down Assembly of Aligned Cellulose Nanofibers
Authors: Jia Chao , Chen Chaoji , Kuang Yudi , Fu Kun , Wang Yilin , Yao Yonggang , Kronthal Spencer , Hitz Emily , Song Jianwei , Xu Fujun , Liu Boyang , Hu Liangbing
Published: June 2018

Advanced textiles made of macroscopic fibers are usually prepared from synthetic fibers, which have changed lives over the past century. The shortage of petrochemical resources, however, greatly limits the development of the textile industry. Here, a facile top‐down approach for fabricating macroscopic wood fibers for textile applications (wood‐textile fibers) comprising aligned cellulose nanofibers directly from natural wood via delignification and subsequent twisting is demonstrated. Inherently aligned cellulose nanofibers are well retained, while the microchannels in the delignified wood are squeezed and totally removed by twisting, resulting in a dense structure with approximately two times higher mechanical strength (106.5 vs 54.9 MPa) and ≈20 times higher toughness (7.70 vs 0.36 MJ m−3) than natural wood. Dramatically different from natural wood, which is brittle in nature, the resultant wood‐textile fibers are highly flexible and bendable, likely due to the twisted structures. The wood‐textile fibers also exhibit excellent knitting properties and dyeability, which are critical for textile applications. Furthermore, functional wood‐textile fibers can be achieved by preinfiltrating functional materials in the delignified wood film before twisting. This top‐down approach of fabricating aligned macrofibers is simple, scalable, and cost‐effective, representing a promising direction for the development of smart textiles and wearable electronics.
Crystal Phase and Architecture Engineering of Lotus‐Thalamus‐Shaped Pt‐Ni Anisotropic Superstructures for Highly Efficient Electrochemical Hydrogen Evolution
Authors: Zhang Zhicheng , Liu Guigao , Cui Xiaoya , Chen Bo , Zhu Yihan , Gong Yue , Saleem Faisal , Xi Shibo , Du Yonghua , Borgna Armando , Lai Zhuangchai , Zhang Qinghua , Li Bing , Zong Yun , Han Yu , Gu Lin , Zhang Hua
Published: June 2018

The rational design and synthesis of anisotropic 3D nanostructures with specific composition, morphology, surface structure, and crystal phase is of significant importance for their diverse applications. Here, the synthesis of well‐crystalline lotus‐thalamus‐shaped Pt‐Ni anisotropic superstructures (ASs) via a facile one‐pot solvothermal method is reported. The Pt‐Ni ASs with Pt‐rich surface are composed of one Ni‐rich “core” with face‐centered cubic (fcc) phase, Ni‐rich “arms” with hexagonal close‐packed phase protruding from the core, and facet‐selectively grown Pt‐rich “lotus seeds” with fcc phase on the end surfaces of the “arms.” Impressively, these unique Pt‐Ni ASs exhibit superior electrocatalytic activity and stability toward the hydrogen evolution reaction under alkaline conditions compared to commercial Pt/C and previously reported electrocatalysts. The obtained overpotential is as low as 27.7 mV at current density of 10 mA cm−2, and the turnover frequency reaches 18.63 H2 s−1 at the overpotential of 50 mV. This work provides a new strategy for the synthesis of highly anisotropic superstructures with a spatial heterogeneity to boost their promising application in catalytic reactions.
Anisotropic Nanoscale Wrinkling in Solid‐State Substrates
Authors: Giordano Maria Caterina , de Mongeot Francesco Buatier
Published: June 2018

Pattern formation induced by wrinkling is a very common phenomenon exhibited in soft‐matter substrates. In all these systems, wrinkles develop in the presence of compressively stressed thin films lying on compliant substrates. Here, the controlled growth of self‐organized nanopatterns exploiting a wrinkling instability on a solid‐state substrate is demonstrated. Soda‐lime glasses are modified in the surface layers by a defocused ion beam, which triggers the formation of a compressively stressed surface layer deprived of alkali ions. When the substrate is heated up near its glass transition temperature, the wrinkling instability boosts the growth rate of the pattern by about two orders of magnitude. High‐aspect‐ratio anisotropic ripples bound by faceted ridges are thus formed, which represent an optimal template for guiding the growth of large‐area arrays of functional nanostructures. The engineering over large square centimeter areas of quasi‐1D arrays of Au nanostripe dimers endowed with tunable plasmonic response, strong optical dichroism, and high electrical conductivity is demonstrated. These peculiar functionalities allow these large‐area substrates to be exploited as active metamaterials in nanophotonics, biosensing, and optoelectronics.
Calcinable Polymer Membrane with Revivability for Efficient Oily‐Water Remediation
Authors: Zhu Zhigao , Wang Wei , Qi Dianpeng , Luo Yifei , Liu Yuanren , Xu Ying , Cui Fuyi , Wang Ce , Chen Xiaodong
Published: June 2018

Fouling of polymeric membranes remains a major challenge for long‐term operation of oily‐water remediation. The common reclamation methods to recycle fouled membranes have the issues of either incomplete degradation of organic pollutants or damage to filter membranes. Here, a calcinable polymer membrane with effective reclamation after fouling is reported, which shows full recovery of the original oil/water separation efficiency. The membrane is made of polysulfonamide/polyacrylonitrile fibers by emulsion electrospinning, followed by hydrothermal decoration of TiO2 nanoparticles. The bonding structured fibrous membrane displays outstanding thermal stability in air (400 °C), strong acid/alkali resistance (at the pH range from 1 to 13), and robust tensile strength. As a result, the chemically fouled polymeric membrane can be easily reclaimed without decreasing in separation performance and mechanical properties by annealing treatment. As a proof‐of‐concept, the as‐prepared membrane is integrated into a wastewater separation tank, which achieves a high water flux over 3000 L m−2 h−1 and oil rejection efficiency of 99.6% for various oil‐in‐water emulsions. The presented strategy on membrane fabrication is believed to be an effective remedy for membrane fouling, and should apply in a wider field of filtration industry.
Progress in Self‐Healing Fiber‐Reinforced Polymer Composites
Authors: Cohades Amaël , Branfoot Callum , Rae Steven , Bond Ian , Michaud Véronique
Published: June 2018

This paper sets out to review the current state of the art in applying self‐healing/self‐repair to high‐performing advanced fiber‐reinforced polymer composite materials (FRPs). A significant proportion of self‐healing studies have focused so far on developing and assessing healing efficiency of bulk polymer systems, applied to particulate composites or low‐volume fraction fiber‐reinforced materials. Only limited research is undertaken on self‐healing in advanced structural FRP composite materials. This review focuses on what is achieved to date, the ongoing challenges which have arisen in implementing self‐healing into FRPs, how considerations for industrialization and large‐scale manufacture must be considered from the outset, where self‐healing may provide most benefits, and how a functionality like self‐healing can be validated for application in real structures. Systems are compared in terms of process parameters, resulting mechanical properties, methods of healing assessment, as well as values of healing quantification. Guidelines are further given for a concerted effort to drive toward standardization of tests and the use of specific reinforcement architectures in order to allow reliable comparison between the available healing systems in structural composites.
Validation of Self‐Healing Properties of Construction Materials through Nondestructive and Minimal Invasive Testing
Authors: Snoeck Didier , Malm Fabian , Cnudde Veerle , Grosse Christian U. , Van Tittelboom Kim
Published: June 2018

When studying the self‐healing properties of construction materials, a plethora of destructive and nondestructive testing (NDT) techniques can be used. In this review, the applicability of different nondestructive test methods is discussed in detail. The methods can be categorized whether they are used to study the encapsulation and/or protection mechanism of the healing agent, the sequestered healing agent itself, the distribution of healing agents, the trigger mechanism for healing, the healing efficiency, or healing performance. Based on this categorization, nondestructive techniques found in literature are discussed. In this way, a robust understanding of the different techniques can be used for future research on self‐healing construction materials.
Immobilization of cis‐4‐Hydroxydiphenylprolinol Silyl Ethers onto Polystyrene. Application in the Catalytic Enantioselective Synthesis of 5‐Hydroxyisoxazolidines in Batch and Flow
Authors: Lai Junshan , Sayalero Sonia , Ferrali Alessandro , Osorio‐Planes Laura , Bravo Fernando , Rodríguez‐Escrich Carles , Pericàs Miquel A.
Published: June 2018

A new family of polystyrene‐supported cis‐4‐hydroxydiphenylprolinol silyl ethers has been prepared, and the resulting polymers have been evaluated as organocatalysts to promote the tandem reaction between N‐protected hydroxylamines and α,β‐unsaturated aldehydes in batch and flow. The new PS‐supported catalysts compare favorably with well‐established immobilized Jørgensen‐Hayashi catalysts, affording 5‐hydroxyisoxazolidines as single diastereoisomers with high enantioselectivities and good yields (up to 83% yield, up to 99% ee).

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One‐Step Preparation of Non‐Covalent Functionalized Carboxylic Multi‐Walled Carbon Nanotubes/Polymethyl Methacrylate Nanocomposites Via In Situ Polymerization
Authors: Jiang Yu , Wang Xiang , Yu Zongzhi , Zheng Junping
Published: June 2018

In this work, methyl methacrylate (MMA) copolymerized with cationic monomer 2‐(methacryloyloxy)ethyltrimethylammonium chloride (MTC) via in situ suspension copolymerization, meanwhile, negatively charged carboxylic multi‐walled carbon nanotubes (MWCNTs) were adsorbed through electrostatic interactions during copolymerization process to fabricate nanocomposites. The chemical structure of copolymer was analyzed by1H nuclear magnetic resonance (1H‐NMR). The interfacial adhesion betweenMWCNTs and polymer matrix was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The morphologies of synthesized microspheres were observed bySEM. Finally, the mechanical properties of nanocomposites were investigated in detail. The results suggest that: the nanocomposites have been successfully synthesized by in situ suspension copolymerization; both the dispersion ofMWCNTs and interfacial adhesion betweenMWCNTs and matrix were improved; and the mechanical properties of nanocomposites were dramatically reinforced. The nanocomposites were prepared in one step without additional treatments ofMWCNTs or copolymer matrix, which makes the method relatively efficient.
Fiber prepared via swelling and thermal cross‐linking as reusable Fenton catalyst for methylene blue decolorization
Authors: Lv Yuanyuan , Xu Naiku , Feng Yan , Lu Yuyao
Published: June 2018

Swelling was first adopted to transform the close‐packed structure of as‐spun poly (acrylic acid‐co‐hydroxyethyl methacrylate) fiber prepared via wet spinning into loose and porous structure. This structure enabled the fiber to carry a large number of iron ions within a certain period of time. Thermal cross‐linking was subsequently conducted to prevent methylene blue solution leaching iron ions out from the fiber. The Fenton catalyst based on the combination of the fiber and iron ions prepared via swelling and thermal cross‐linking exhibited excellent reusability in decolorizing MB. The research results showed that more than 95% of MB could be decolorized from 10 ml of MB solution with the concentration of 20 mg/L in the presence of 2 μl of H2O2 and about 5 mg of virgin catalyst, and even when the catalyst was used for the tenth time, MB decolorization efficiency still reached up to 88%. In addition, the difference of swelling processes also caused the result that the corresponding catalysts had different thermal properties.
Electrochemistry and Solid‐State Chemistry of NaMeO2 (Me = 3d Transition Metals)
Authors: Kubota Kei , Kumakura Shinichi , Yoda Yusuke , Kuroki Kazutoshi , Komaba Shinichi
Published: June 2018

Sodium 3d transition metal oxides for Na‐ion batteries have attracted attention of battery researchers because of their new chemistries and abundant material resources in the earth. Some companies have also developed Na‐ion battery prototypes mainly consisting of a layered oxide as a positive electrode material and hard carbon as the negative one for practical use. In this article, progress of Na‐containing layered transition‐metal oxides is reviewed in terms of fundamental chemistry and technology aspects for future batteries as a post Li‐ion battery. To realize practical positive electrode materials is still challenging and the practical issues are discussed. In this context the authors propose strategies for designing layered transition‐metal oxide materials toward realization of practical Na‐ion batteries.
Mucus T helper 2 biomarkers predict chronic rhinosinusitis disease severity and prior surgical intervention
Authors: Turner Justin H. , Li Ping , Chandra Rakesh K.
Published: June 2018

Background

Chronic rhinosinusitis (CRS) is a diverse clinical syndrome with a heterogeneous pathophysiology. Early attempts to identify CRS endotypes and biomarkers have largely relied on analysis of surgically obtained tissue, thus limiting their practical utility. This study examined the ability of mucus T helper 2 (Th2) biomarkers to predict CRS disease severity and clinical characteristics.

Methods

CRS (n = 90) and healthy control subjects (n = 17) were prospectively enrolled prior to surgical intervention and mucus levels of interleukin (IL)‐4, IL‐5, and IL‐13 were determined using a multiplex cytometric bead assay. Data for relevant cytokines was then scaled, normalized, and later combined to develop standardized metrics indicative of Th2‐associated inflammation. Th2‐high and Th2‐low subgroups were consequently identified and validated against factors associated with disease severity and clinical outcomes.

Results

Mucus levels of IL‐5 and IL‐13 were elevated in CRS subjects compared to controls, while no significant difference was noted for IL‐4. IL‐5 and IL‐13 high CRS were associated with worse objective measures of disease severity and greater rates of revision surgery. Similar relationships were noted for both cytokines when CRS with nasal polyps (CRSwNP) patients were analyzed separately. Th2‐high CRS and Th2‐low CRS were then categorized using a scaled IL‐5/IL‐13 metric. Th2‐high CRS was characterized by an increased number of subjects with nasal polyps and comorbid asthma, and worse symptom and computed tomography (CT) scores.

Conclusion

The Th2‐associated cytokines, IL‐5 and IL‐13, are detectable in sinonasal mucus and their levels can be used to define Th2‐high and Th2‐low CRS. Identification of Th2‐high and Th2‐low endotypes using mucus‐based biomarkers could facilitate stratification of CRS subgroups and guide personalized therapies.
Complete Switch of Reaction Specificity of an Aldolase by Directed Evolution In Vitro: Synthesis of Generic Aliphatic Aldol Products
Authors: Junker Sebastian , Roldan Raquel , Joosten Henk‐Jan , Clapés Pere , Fessner Wolf‐Dieter
Published: June 2018

A structure‐guided engineering of fructose‐6‐phosphate aldolase was performed to expand its substrate promiscuity toward aliphatic nucleophiles, that is, unsubstituted alkanones and alkanals. A “smart” combinatorial library was created targeting residues D6, T26, and N28, which form a binding pocket around the nucleophilic carbon atom. Double‐selectivity screening was executed by high‐performance TLC that allowed simultaneous determination of total activity as well as a preference for acetone versus propanal as competing nucleophiles. D6 turned out to be the key residue that enabled activity with non‐hydroxylated nucleophiles. Altogether 25 single‐ and double‐site variants (D6X and D6X/T26X) were discovered that show useful synthetic activity and a varying preference for ketone or aldehyde as the aldol nucleophiles. Remarkably, all of the novel variants had completely lost their native activity for cleavage of fructose 6‐phosphate.
An Interrupted Pummerer/Nickel‐Catalysed Cross‐Coupling Sequence
Authors: Aukland Miles H. , Talbot Fabien J. T. , Fernández‐Salas José A. , Ball Matthew , Pulis Alexander P. , Procter David J.
Published: June 2018

An interrupted Pummerer/nickel‐catalysed cross‐coupling strategy has been developed and used in the elaboration of styrenes. The operationally simple method can be carried out as a one‐pot process, involves the direct formation of stable alkenyl sulfonium salt intermediates, utilises a commercially available sulfoxide, catalyst, and ligand, operates at ambient temperature, accommodates sp‐, sp2‐, and sp3‐hybridised organozinc coupling partners, and delivers functionalised styrene products in high yields over two steps. An interrupted Pummerer/cyclisation approach has also been used to access carbo‐ and heterocyclic alkenyl sulfonium salts for cross‐coupling.
Ligandenaktivierte enantioselektive C‐H‐Aktivierung von Tetrahydrochinolinen und gesättigten Aza‐Heterocyclen durch RhI
Authors: Greßies Steffen , Klauck Felix J. R. , Kim Ju Hyun , Daniliuc Constantin G. , Glorius Frank
Published: June 2018

Die erste Rhodium(I)‐katalysierte enantioselektive intermolekulare C
‐H‐Aktivierung verschiedener gesättigter Aza‐Heterocyclen einschließlich Tetrahydrochinolinen, Piperidinen, Piperazinen, Azetidinen, Pyrrolidinen, Azepanen und anderen wird beschrieben. Die Kombination eines Rhodium(I)‐Präkatalysators und eines chiralen einzähnigen Phosphonitliganden ist ein leistungsfähiges katalytisches System, um aus einfachen Ausgangsmaterialien eine Vielzahl von wichtigen enantiomeren‐angereicherten Heterocyclen herzustellen. Die C
‐H‐Aktivierung von Tetrahydrochinolinen ist aufgrund der benachbarten C
‐H‐Bindung besonders anspruchsvoll. Diese redoxneutrale Methode bietet einen neuen Syntheseweg für α‐N‐arylierte Heterocyclen mit hoher Chemoselektivität und Enantioselektivität von bis zu 97 % ee.
Sequencing 5‐Hydroxymethyluracil at Single‐Base Resolution
Authors: Kawasaki Fumiko , Martínez Cuesta Sergio , Beraldi Dario , Mahtey Areeb , Hardisty Robyn E. , Carrington Mark , Balasubramanian Shankar
Published: June 2018

5‐hydroxymethyluracil (5hmU) is formed through oxidation of thymine both enzymatically and non‐enzymatically in various biological systems. Although 5hmU has been reported to affect biological processes such as protein–DNA interactions, the consequences of 5hmU formation in genomes have not been yet fully explored. Herein, we report a method to sequence 5hmU at single‐base resolution. We employ chemical oxidation to transform 5hmU to 5‐formyluracil (5fU), followed by the polymerase extension to induce T‐to‐C base changes owing to the inherent ability of 5fU to form 5fU:G base pairing. In combination with the Illumina next generation sequencing technology, we developed polymerase chain reaction (PCR) conditions to amplify the T‐to‐C base changes and demonstrate the method in three different synthetic oligonucleotide models as well as part of the genome of a 5hmU‐rich eukaryotic pathogen. Our method has the potential capability to map 5hmU in genomic DNA and thus will contribute to promote the understanding of this modified base.
Crystallographic Evidence for a Sterically Induced Ferryl Tilt in a Non‐Heme Oxoiron(IV) Complex that Makes it a Better Oxidant
Authors: Rasheed Waqas , Draksharapu Apparao , Banerjee Saikat , Young Victor G. , Fan Ruixi , Guo Yisong , Ozerov M. , Nehrkorn Joscha , Krzystek J. , Telser Joshua , Que Lawrence
Published: June 2018

Oxoiron(IV) units are often implicated as intermediates in the catalytic cycles of non‐heme iron oxygenases and oxidases. The most reactive synthetic analogues of these intermediates are supported by tetradentate tripodal ligands with N‐methylbenzimidazole or quinoline donors, but their instability precludes structural characterization. Herein we report crystal structures of two [FeIV(O)(L)]2+ complexes supported by pentadentate ligands incorporating these heterocycles, which show longer average Fe–N distances than the complex with only pyridine donors. These longer distances correlate linearly with log k2′ values for O‐ and H‐atom transfer rates, suggesting that weakening the ligand field increases the electrophilicity of the Fe=O center. The sterically bulkier quinoline donors are also found to tilt the Fe=O unit away from a linear N‐Fe=O arrangement by 10°.
Cinchonamine Squaramide Catalyzed Asymmetric aza‐Michael Reaction: Dihydroisoquinolines and Tetrahydropyridines
Authors: Roy Tarun Kumar , Parhi Biswajit , Ghorai Prasanta
Published: June 2018

The first example of a chiral cinchona‐squaramide catalyzed enantioselective intramolecular aza‐Michael addition for the synthesis of dihydroisoquinolines and tetrahydropyridines has been developed. In general, good yields and excellent enantioselctivities were observed. Broad classes of Michael acceptors, such as enones, esters, thioesters, and Weinreb amides, were successful substrates. The possibility of recycling the catalysts has also been demonstrated. An oxidation of combined enamine and keto functionalities on chiral dihydroisoquinolines leads to a single diastereomer of an architecturally unprecedented tetracyclic core without loss in enantioselectivity.
Stable Diporphyrinylaminyl Radical and Nitrenium Ion
Authors: Shimizu Daiki , Fujimoto Keisuke , Osuka Atsuhiro
Published: June 2018

Nitrenium ions, isoelectronic nitrogen counterparts of carbenes, are important intermediates in various biological and chemical processes. Herein we describe the first synthesis and characterization of a stable nitrenium ion without resonance stabilization by adjoining amino groups. Namely, a stable salt of a diporphyrinylnitrenium ion was synthesized by stepwise oxidation of the corresponding diporphyrinylamine through a stable aminyl radical. The nitrenium ion exhibits characteristic features such as a singlet ground state, enhanced double‐bond character of the central C−N bonds, no reactivity toward water and methanol, and negative solvatochromic behavior.
Continuous Visible‐Light Photoflow Approach for a Manganese‐Catalyzed (Het)Arene C−H Arylation
Authors: Liang Yu‐Feng , Steinbock Ralf , Yang Long , Ackermann Lutz
Published: June 2018

Manganese photocatalysts enabled versatile room‐temperature C−H arylation reactions by means of continuous visible‐light photoflow, thus allowing for efficient C−H arylations in 30 minutes with ample scope. The robustness of the manganese‐catalyzed photoflow strategy was shown by visible light‐induced gram‐scale synthesis, clearly outperforming the batch performance.
Ligand‐Enabled Enantioselective C–H Activation of Tetrahydroquinolines and Saturated Aza‐Heterocycles by RhI
Authors: Greßies Steffen , Klauck Felix J. R. , Kim Ju Hyun , Daniliuc Constantin G. , Glorius Frank
Published: June 2018

The first rhodium(I)‐catalyzed enantioselective intermolecular C
–H activation of various saturated aza‐heterocycles including tetrahydroquinolines, piperidines, piperazines, azetidines, pyrrolidines, and azepanes is presented. The combination of a rhodium(I) precatalyst and a chiral monodentate phosphonite ligand is shown to be a powerful catalytic system to access a variety of important enantio‐enriched heterocycles from simple starting materials. Notably, the C
–H activation of tetrahydroquinolines is especially challenging due to the adjacent C
−H bond. This redox‐neutral methodology provides a new synthetic route to α‐N‐arylated heterocycles with high chemoselectivity and enantioselectivity up to 97 % ee.
Palladium‐anchored multidentate SBA‐15/di‐urea nanoreactor: A highly active catalyst for Suzuki coupling reaction
Authors: Rohani Sahar , Mohammadi Ziarani Ghodsi , Badiei Alireza , Ziarati Abolfazl , Jafari Maryam , Shayesteh Alireza
Published: June 2018

Modification of mesoporous silica was carried out by reaction of SBA‐15 with di‐urea‐based ligand. Next, with the help of this ligand, palladium ions were anchored within the multidentate SBA‐15/di‐urea pore channels with high dispersion. The SBA‐15/di‐urea/Pd catalyst was characterized using various techniques. Theoretical calculations indicated that each palladium ion was strongly interacted with one nitrogen and two oxygen atoms from the multidentate di‐urea ligand located in SBA‐15 channels and these interactions remained during the catalytic cycle. These results are in good agreement with those of hot filtration test: the palladium ions have very high stability against leaching from the SBA‐15/di‐urea support. The catalytic performance of SBA‐15/di‐urea/Pd nanostructure was examined for the Suzuki coupling reaction of phenylboronic acid and electronically diverse aryl halides under mild conditions with a minimal amount of Pd (0.26 mol%). Compared to previous reports, this protocol afforded some advantages such as short reaction times, high yields of products, catalyst stability without leaching, easy catalyst recovery and preservation of catalytic activity for at least six successive runs.
Synthesis and characterization of MCM‐41‐Biurea‐Pd as a heterogeneous nanocatalyst and using its catalytic efficacy in C–C, C–N and C–O coupling reactions
Authors: Batmani Hana , Noroozi Pesyan Nader , Havasi Forugh
Published: June 2018

MCM‐41‐Biurea‐Pd is introduced as a new, heterogeneous and reusable catalyst for C–C and C–heteroatom bond formation between various aryl halides, phenols and amines, in the presence of Ph3SnCl (Stille reaction) in PEG‐400 as a green solvent at room temperature. The structure of the functionalized MCM‐41 was analysed using various techniques.
Cu(II) Schiff base complex supported on Fe3O4 nanoparticles as an efficient nanocatalyst for the selective aerobic oxidation of alcohols
Authors: Aghajani Milad , Monadi Niaz
Published: June 2018

Herein, we have prepared a new Cu(II) Schiff base complex supported onto the surface of modified Fe3O4 nanoparticles as highly stable, heterogeneous and magnetically recyclable nanocatalyst for the selective aerobic oxidation of different alcohols. The structure, morphology, chemical composition and magnetic property of the nanocatalyst and its precursors were characterized using FT‐IR, TGA, AAS, ICP‐AES, XRD, SEM, EDS, VSM and N2 adsorption–desorption analyses. Characterization results exhibited the uniform spherical morphology for nanocatalyst and its precursors. A promising eco‐friendly method with short reaction time and high conversion and selectivity for oxidation of various primary and secondary alcohols under O2 atmosphere condition was achieved. The synthesized nanocatalyst could be recovered easily by applying an external magnetic field and reused for least eight subsequent reaction cycles with only negligible deterioration in catalytic performance.
Gold(I) bis(N‐heterocyclic carbene) complexes: Metabolic stability, in vitro inhibition, and genotoxicity
Authors: Tan Jackie , Sivaram Haresh , Huynh Han Vinh
Published: June 2018

We report the profiling of the metabolic stability, normal cell inhibition, and genotoxicity of the two gold complexes [Au (iPr2‐bimy)2]PF6 (1) and [Au (Fpyr)(iPr2‐bimy)]PF6 (2), which show strong apoptotic activities in lung cancer cells. Liver microsomal tests revealed that the compounds have a relatively high half‐life compared to midazolam and do not suffer rapid metabolism and in vitro clearance. The cytotoxic potential of these compounds were also relatively weak in normal cells, with higher IC50 values compared to cancer cells, with a 2–60 times difference. The Ames test revealed that the compounds do not give rise to any mutations as well. Overall, the compounds showed stability in liver microsomes, specificity for cancer cells, and a lack of genotoxic potential.
Recovery and Recycling of Isopropyl Alcohol Used in Biodiesel Production From Yellow Mustard Oil
Authors: Sinichi Sayeh , Diosady Levente L.
Published: June 2018

The recovery of solvents used during biodiesel synthesis is an important factor in the economic feasibility and sustainability of the entire process. In this study, we looked at the use of isopropyl alcohol (IPA) for oil extraction and biodiesel production, as well as its potential for recovery and recycling. We found that multistage extraction improved oil recovery, with up to 86% oil yield using four stages of extraction at an IPA:mustard flour (volume:weight) ratio of 1.5:1 at room temperature. Using acid–base‐catalyzed transesterification, 99% of the mustard oil was converted to biodiesel. At the end of this process, IPA was recovered from the azeotrope by salting out using potassium carbonate or sodium carbonate. The solubility behavior of the components was evaluated by means of ternary‐phase diagrams of IPA/water/sodium carbonate and IPA/water/potassium carbonate, which determined their liquid–liquid–solid equilibrium constants at ambient pressure and at room temperature. Using 20% (w:w) potassium carbonate, 95% of the IPA was recovered at 99% purity from a starting mixture of IPA containing 13% water. Azeotropic distillation of the IPA–water azeotrope with 10% potassium carbonate resulted in the recovery of 99% of the IPA at 94% purity. These results suggest that IPA is not only a suitable solvent for mustard‐oil extraction but also for salt‐enhanced azeotropic distillation resulting in near‐complete recovery from aqueous solutions.
Effect of surface chemistry and morphology of silica on the thermal and mechanical properties of silicone elastomers
Authors: Tong Yuejing , Liu Hangzhong , Chen Aicheng , Guan Huaimin , Kong Junhua , Liu Songlin , He Chaobin
Published: June 2018

In this study, high‐temperature vulcanized silicone rubbers (HTV‐SRs) using fumed silica (FSi), precipitated silica (PSi), and modified precipitated silica (MPSi) as reinforcing fillers were prepared. The effect of morphology and surface chemistry of the silica on the thermal and mechanical properties of the resultant silicone rubbers was investigated using curing rheometer, scanning electron microscopy, mechanical test, and dynamic mechanical analysis. The thermo‐oxidative stability and solvent resistance of the vulcanized silicone rubbers were further evaluated via heat ageing test, extraction, and swelling experiments. It is shown that the mechanical properties (tensile modulus and tensile strength) of the as‐prepared HTV‐SRs are in the order of FSi > PSi > MPSi, which could be attributed to the molecular interaction between the filler and the matrix. FSi has the highest surface area, which enhances the hydrogen bonding interaction between the filler and the silicone matrix; while MPSi, in which part of SiOH groups have been consumed during modification, shows the weakest interaction among the three. The filler–matrix interaction could also explain the lowest swelling and sol fraction in FSi‐filled HTV‐SR, and the low viscosity and good processibility of PSi‐ and MPSi‐filled HTV‐SR. Furthermore, it is also shown that the MPSi‐filled HTV‐SR exhibits the highest retention of mechanical properties after thermal aging at 250 °C for 24 h, which could be attributed to the lowest acidity of the fillers. The possible mechanism for acid catalyzed hydrolytic chain scission and intramolecular chain backbiting has been proposed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46646.
Epoxy composites modified with microfibers of potassium polytitanates
Authors: Mostovoy Anton Stanislavovich , Kadykova Yulia Aleksandrovna , Bekeshev Amirbek Zarlykovich , Tastanova Lyazzat Knashevna
Published: June 2018

The research we conducted shows the possibility of the directed adjustment of epoxy composite performance characteristics through the application of small additives of potassium polytitanate whiskers, the introduction of polyfunctional plasticizers with chemical and mechanical methods of activation of the whole composition and its components; this ensured the creation of a new generation of epoxy composites with high‐performance properties (breaking tension = 116 MPa and modulus of elasticity at bending = 3150 MPa, destructive tension under compression = 95 MPa, impact strength = 18 kJ/m2 that meets the requirements of most industries. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46651.
A new approach for flexible PBAT/PLA/CaCO3 films into agriculture
Authors: Rocha Daniel Belchior , Souza de Carvalho Jéssika , de Oliveira Sueli Aparecida , dos Santos Rosa Derval
Published: June 2018

The use of flexible films in agriculture has increased intensely in the last 15 years bringing benefits to producers. However, environmental impacts increased due to their incorrect post‐use disposal which leads the degradable films to emerge as an alternative. The production films of poly(butylene adipate‐co‐terephthalate) and poly(lactic acid) reinforced with calcium carbonate (CaCO3) was studied focusing on producing lower cost materials and flexible films. Four different films (reinforcement compositions) were prepared by melt extrusion with 10 and 20 wt % of CaCO3. Mechanical and thermal properties, crystallinity, water absorption, and soil degradation, were evaluated. The addition of reinforcement leads to improved compatibility between the polymers in the matrix, which usually presented phase segregation. The films showed better mechanical properties with the addition of CaCO3. Highly orientated amorphous structures were obtained leading to low water absorption and low degradation in the simulated soil. This low degradation, suggests that the obtained films would be of interest in flexible mulch films manufacturing, particularly for Muridori plantation system, where long‐term plantations are needed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46660.
Influence of Laponite RD on the properties of poly(vinyl alcohol) hydrogels
Authors: Morariu Simona , Bercea Maria , Brunchi Cristina‐Eliza
Published: June 2018

Poly(vinyl alcohol) (PVA) hydrogels were prepared in the presence/absence of Laponite RD (LRD) by using glutaraldehyde (GL) as chemical crosslinker. The effect of GL concentration (CHO/OH ratio between 0.02 and 0.38) and of clay addition on the PVA hydrogel properties was investigated. The swollen hydrogels showed good transparency and flexibility. LRD incorporation into the PVA hydrogel, revealed by Fourier transform infrared spectroscopy, led to a significant increase of the roughness of the dried hydrogel surface (about two times), as established by atomic force microscopy. The swelling ability was affected in a small extent by the clay addition. The elastic modulus decreased from 4680 to 3340 Pa and from 2195 to 1603 Pa by addition of 0.5% LRD into PVA hydrogels obtained with CHO/OH ratio of 0.02 and 0.06, respectively. The LRD addition reduced the gelation time determined by in situ rheological monitoring of PVA crosslinking reaction. The experimental investigations showed that there is an optimum CHO/OH ratio of 0.02 for which the PVA/LRD hybrid hydrogel presents the properties required by a targeted application, as for example support material for wound dressings. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46661.
Blocked melamine–urea–formaldehyde resins and their usage in agglomerated cork panels
Authors: Antunes Ana , Gomes Ana , Paiva Nádia , Ferra João , Martins Jorge , Carvalho Luísa , Barros‐Timmons Ana , Magalhães Fernão D.
Published: June 2018

Caprolactam and o‐p‐toluenesulfonamide are tested as chain‐growth blockers for melamine–urea–formaldehyde (MUF) resins, in an attempt to reduce the crosslinking density of the cured resin and hence improve its flexibility. Agglomerated cork panels, for which flexibility is a technical demand, were produced with the modified resins and tested. The blockers were added at three different steps in the synthesis process: methylolation, condensation, and at the end of the synthesis. Besides evaluation of standard properties, resins were characterized using gel permeation chromatography and Fourier transform infrared. Blocked resins showed better storage stability and improved water tolerance, especially when caprolactam was employed. When used as binders in agglomerated cork panels, the blocked resins allowed for significantly better flexibility, evaluated in terms of mandrel bending test. The tensile resistance of the panels remained well within the desired limits for this type of material. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46663.
Surfaces modification of methylcellulose: Cobalt nitrate polymer electrolyte by sulfurated hydrogen gas treatment
Authors: Abdullah Omed Gh. , Aziz Bakhtyar K. , Aziz Shujahadeen B. , Suhail Mahdi H.
Published: June 2018

This article discusses the surface modification of methylcellulose:nitrate cobalt [MC:Co(NO3)2] through the sulfurated hydrogen (H2S) gas treatment. Solution cast technique has been used to fabricate MC:Co(NO3)2‐based solid polymer electrolytes. The results achieved for structural, morphological and optical properties indicate that H2S gas treatment is crucial for modification of polymer electrolytes to polymer composites. The morphological appearance revealed that the H2S gas treatment produced cobalt sulfide (CoS) nanoparticles on the surface of the films. The results of X‐ray diffraction indicate the disruption of the crystalline phase of the MC polymer upon addition of various amounts of Co(NO3)2 salt. The optical absorption spectra of the electrolyte samples shifted to higher wavelengths with increasing the cobalt nitrate salt concentration. The optical band gap of MC incorporated with 40 wt % Co(NO3)2 concentration was 4.69 and reduced to 4.52 eV after H2S surface treatment. The linear relationship between the refractive index and salt concentration supports the uniform distribution of the developed nanoparticles appeared in STM images. The significant change in intensity and position of Fourier transform infrared transmittance bands is an evidence for the formation of charge transfer complex between the added salt and the MC host polymer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46676.
Functionalized polymeric membrane with aquaporin using click chemistry for water purification application
Authors: He Yuan , Hoi Hiofan , Montemagno Carlo D. , Abraham Sinoj
Published: June 2018

A new type of aquaporin‐based biomimetic water purification membrane is fabricated using a propargyl functionalized β‐sheet peptide (FBP1). FBP1 is demonstrated to bind to aquaporin and form a stable protein–peptide complex in aqueous solution, as well as covalently conjugate with azide group. Substrate starting material, polysulfone (PSU), is modified with ∼1.05 azide group per repeating unit and casted into a thin film substrate with appropriate pore size structure using non‐solvent induced phase separation technique. Protein–peptide complex then is clicked onto the substrate using an in‐house built circulating system. The successful immobilization is verified by surface chemical composition analysis and surface morphology analysis. The preliminary salt rejection results show salt rejection improvement from 5% of control membrane to 12.5%. We thus demonstrate a promising method to conjugate a thin layer of membrane protein onto polymeric substrate and well maintain the functionality of membrane proteins. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46678.
Synthesis and glutathione reductase inhibitory properties of 5‐methyl‐2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐one's aryl Schiff base derivatives
Authors: Balaydın Halis Türker , Özil Musa , Şentürk Murat
Published: June 2018

Glutathione reductase (GR) is responsible for the existence of the reduced glutathione (GSH) molecule, a crucial antioxidant against oxidative stress reagents. The antimalarial activities of some redox active compounds are attributed to their inhibition of antioxidant flavoenzyme GR, and inhibitors are therefore expected to be useful for the treatment of malaria. In this work, a fast and effective synthesis and the GR inhibitory properties of 5‐methyl‐2,4‐dihydro‐3H‐1,2,4‐triazol‐3‐one's aryl Schiff base derivatives are reported. For this aim, the triazol nucleus was obtained, which was substituted with identical groups: ester, hydrazide, and Schiff base system at the N‐2 and N‐4 nitrogen atoms. The majority of the reactions were carried out by utilizing both microwave and conventional methods in order to compare their yields and reaction times. Beside this, the occuring E/Z geometrical isomers from the CN double bond and the cis/trans amide conformers at the CONH single bond were studied. In the biological activity section of this work, it was found that all synthesized compounds have better inhibitory activity than N,N‐bis(2‐chloroethyl)‐N‐nitrosourea against GR; especially, two molecules, 6e and 6f, are the best among them. The evidence indicates that these Schiff base derivatives, with triazole ring, are strong GR inhibitors and novel antimalaria candidates.
The influence of managerial satisfaction on corporate environmental performance and reputation
Authors: Daddi Tiberio , Iraldo Fabio , Testa Francesco , De Giacomo Maria Rosa
Published: June 2018

Organizational studies have widely debated the relationship between job satisfaction and job performance. Some papers have dealt with managerial satisfaction and businesses' performance adopting agency theory to interpret the results. However, no studies have yet considered the relationship between the satisfaction levels of an environmental manager and corporate environmental performance. This paper thus analyses the role played by the environmental manager's satisfaction in enhancing corporate environmental performance and reputation. The paper uses data from a survey of 412 Eco Management and Audit Scheme registered organizations. The results show a positive relationship between managerial satisfaction and environmental performance, whereas no such positive relationship was found when considering eco‐innovation performance. In addition, the environmental manager's satisfaction has a positive and indirect influence on the corporate environmental reputation. These results contribute to the literature on agency theory and aim to extend the debate between job satisfaction and job performance to the sustainable business field.
Critical assessment of the efficiency of CD34 and CD133 antibodies for enrichment of rabbit hematopoietic stem cells
Authors: Vašíček Jaromír , Shehata Medhat , Schnabl Susanne , Hilgarth Martin , Hubmann Rainer , Jäger Ulrich , Bauer Miroslav , Chrenek Peter
Published: June 2018

Rabbits have many hereditary diseases common to humans and are therefore a valuable model for regenerative disease and hematopoietic stem cell (HSC) therapies. Currently, there is no substantial data on the isolation and/or enrichment of rabbit HSCs. This study was initiated to evaluate the efficiency of the commercially available anti‐CD34 and anti‐CD133 antibodies for the detection and potential enrichment of rabbit HSCs from peripheral blood. PBMCs from rabbit and human blood were labelled with different clones of anti‐human CD34 monoclonal antibodies (AC136, 581, and 8G12) and rabbit polyclonal CD34 antibody (pCD34) and anti‐human CD133 monoclonal antibodies (AC133 and 293C3). Flow cytometry showed a higher percentage of rabbit CD34+ cells labelled by AC136 in comparison to the clone 581 and pCD34 (P < 0.01). A higher percentage of rabbit CD133+ cells were also detected by 293C3 compared to the AC133 clone (P < 0.01). Therefore, AC136 clone was used for the indirect immunomagnetic enrichment of rabbit CD34+ cells using magnetic‐activated cell sorting (MACS). The enrichment of the rabbit CD34+ cells after sorting was low in comparison to human samples (2.4% vs. 39.6%). PCR analyses confirmed the efficient enrichment of human CD34+ cells and the low expression of CD34 mRNA in rabbit positive fraction. In conclusion, the tested antibodies might be suitable for detection, but not for sorting the rabbit CD34+ HSCs and new specific anti‐rabbit CD34 antibodies are needed for efficient enrichment of rabbit HSCs. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1278–1289, 2018