bluuebunny/crossref_metadata_2025 huggingface dataset:
Diverse Ligand‐Functionalized Mixed‐Valent Hexamanganese Sandwiched Silicotungstates with Single‐Molecule Magnet Behavior
Authors: Xue Han , Zhao Jun‐Wei , Pan Rui , Yang Bai‐Feng , Yang Guo‐Yu , Liu Hong‐Sheng
Published: July 2016

Under hydrothermal conditions, replacement of the water molecules in the [MnIII4MnII2O4(H2O)4]8+ cluster of mixed‐valent Mn6 sandwiched silicotungstate [(B‐α‐SiW9O34)2MnIII4MnII2O4(H2O)4]12− (1 a) with organic N ligands led to the isolation of five organic–inorganic hybrid, Mn6‐substituted polyoxometalates (POMs) 2–6. They were all structurally characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, diffuse‐reflectance spectroscopy, and powder and single‐crystal X‐ray diffraction. Compounds 2–6 represent the first series of mixed‐valent {MnIII4MnII2O4(H2O)4−n(L)n} sandwiched POMs covalently functionalized by organic ligands. The preparation of 1–6 not only indicates that the double‐cubane {MnIII4MnII2O4(H2O)4−n(L)n} clusters are very stable fragments in both conventional aqueous solution and hydrothermal systems and that organic functionalization of the [MnIII4MnII2O4(H2O)4]8+ cluster by substitution reactions is feasible, but also demonstrates that hydrothermal environments can promote and facilitate the occurrence of this substitution reaction. This work confirms that hydrothermal synthesis is effective for making novel mixed‐valent POMs substituted with transition‐metal (TM) clusters by combining lacunary Keggin precursors with TM cations and tunable organic ligands. Furthermore, magnetic measurements reveal that 3 and 6 exhibit single‐molecule magnet behavior.
A Hydrophobic Metal–Organic Framework Based on Cubane‐Type [Co4(μ3‐F)3(μ3‐SO4)]3+ Clusters for Gas Storage and Adsorption Selectivity of Benzene over Cyclohexane
Authors: Zhang Lei , Yang Wenbin , Wu Xiao‐Yuan , Lu Can‐Zhong , Chen Wen‐Zhe
Published: July 2016

Hydrophobic metal‐organic frameworks (MOFs) not only have high water stability, but also exhibit high adsorption capacity towards organic molecules, in particular hydrocarbons. Herein we report a rare metal fluoride organic framework MFOF‐1 with high hydrophobicity, which is constructed from unprecedented fluoride‐ and sulfate‐bridged cubane‐type tetranuclear cobalt clusters. MFOF‐1 consists of three types of polyhedral cages with face‐sharing configurations, and possesses a novel (3,9)‐connected 3D+3D→3D self‐interpenetrating array or the rare pyr topology. MFOF‐1 shows high thermal stability and high stability in water and even acid/base aqueous solutions, and exhibits rather high H2 and CO2 storage capacities at ambient pressure. Remarkably, MFOF‐1 shows little adsorption of water but considerably high uptakes of methanol, n‐hexane, cyclohexane, and benzene, and exhibits a certain degree of adsorption selectivity of benzene over cyclohexane.
Chemical Swarming: Depending on Concentration, an Amphiphilic Ruthenium Polypyridyl Complex Induces Cell Death via Two Different Mechanisms
Authors: Siewert Bianka , van Rixel Vincent H. S. , van Rooden Eva J. , Hopkins Samantha L. , Moester Miriam J. B. , Ariese Freek , Siegler Maxime A. , Bonnet Sylvestre
Published: July 2016

The crystal structure and in vitro cytotoxicity of the amphiphilic ruthenium complex [3](PF6)2 are reported. Complex [3](PF6)2 contains a Ru−S bond that is stable in the dark in cell‐growing medium, but is photosensitive. Upon blue‐light irradiation, complex [3](PF6)2 releases the cholesterol–thioether ligand 2 and an aqua ruthenium complex [1](PF6)2. Although ligand 2 and complex [1](PF6)2 are by themselves not cytotoxic, complex [3](PF6)2 was unexpectedly found to be as cytotoxic as cisplatin in the dark, that is, with micromolar effective concentrations (EC50), against six human cancer cell lines (A375, A431, A549, MCF‐7, MDA‐MB‐231, and U87MG). Blue‐light irradiation (λ=450 nm, 6.3 J cm−2) had little influence on the cytotoxicity of [3](PF6)2 after 6 h of incubation time, but it increased the cytotoxicity of the complex by a factor 2 after longer (24 h) incubation. Exploring the unexpected biological activity of [3](PF6)2 in the dark elucidated an as‐yet unknown bifaceted mode of action that depended on concentration, and thus, on the aggregation state of the compound. At low concentration, it acts as a monomer, inserts into the membrane, and can deliver [1]2+ inside the cell upon blue‐light activation. At higher concentrations (>3–5 μm), complex [3](PF6)2 forms supramolecular aggregates that induce non‐apoptotic cell death by permeabilizing cell membranes and extracting lipids and membrane proteins.
Potent Glycosidase Inhibition with Heterovalent Fullerenes: Unveiling the Binding Modes Triggering Multivalent Inhibition
Authors: Abellán Flos Marta , García Moreno M. Isabel , Ortiz Mellet Carmen , García Fernández Jose Manuel , Nierengarten Jean‐Francois , Vincent Stéphane P.
Published: July 2016

Glycosidases are key enzymes in metabolism, pathogenic/antipathogenic mechanisms and normal cellular functions. Recently, a novel approach for glycosidase inhibition that conveys multivalent glycomimetic conjugates has emerged. Many questions regarding the mechanism(s) of multivalent enzyme inhibition remain unanswered. Herein we report the synthesis of a collection of novel homo‐ and heterovalent glyco(mimetic)‐fullerenes purposely conceived for probing the contribution of non‐catalytic pockets in glysosidases to the multivalent inhibitory effect. Their affinities towards selected glycosidases were compared with data from homovalent fullerene conjugates. An original competitive glycosidase–lectin binding assay demonstrated that the multivalent derivatives and the substrate compete for low affinity non‐glycone binding sites of the enzyme, leading to inhibition by a “recognition and blockage” mechanism. Most notably, this work provides evidence for enzyme inhibition by multivalent glycosystems, which will likely have a strong impact in the glycosciences given the utmost relevance of multivalency in Nature.
Development of a Practical Tool for the Assessment of Biological Performances in Wastewater Treatment Plants
Authors: Malinverni Francesca F. , Genon Giuseppe , Ruffino Barbara
Published: July 2016

The presence of residual nitrogen loads in treated wastewater may cause eutrophication in receiving water bodies. Nitrogen removal in wastewater treatment plants (WWTPs) is commonly based on nitrification–denitrification (NdN). This study presents a novel and practical assessment tool which uses mass balances to evaluate the efficiencies of the NdN processes in WWTPs. The tool was tested on a WWTP with a capacity of 137 000 population equivalent. A 6 year (2008–2013) survey of the plant demonstrated that the NdN compartment was not able to guarantee the annual average of 80% for the total nitrogen (TN) removal. This figure is fixed by the local wastewater regulation. From the survey data, the values of the kinetic constants for the processes of biochemical oxygen demand oxidation, nitrification, and denitrification were calculated. With these values the influence of the process parameters (i.e., recycle ratio of the aerated mixture, flow rate, biomass concentration) and plant parameters (volume of the nitrification and denitrification ponds) on the efficiency of TN removal was evaluated. The results of the sensitivity analysis revealed that an intervention on process or plant parameters was not sufficient to reach the requested target of TN removal. Consequently, the introduction of a post‐denitrification module was suggested.
Molybdenum Disulfide‐Coated Lithium Vanadium Fluorophosphate Anode: Experiments and First‐Principles Calculations
Authors: Liu Zhaomeng , Peng Wenjie , Xu Zhenming , Shih Kaimin , Wang Jiexi , Wang Zhixing , Lv Xiaojun , Chen Jiangan , Li Xinhai
Published: July 2016

To develop a new anode material to meet the increasing demands of lithium‐ion battery, MoS2 is used for the first time to modify the C/LiVPO4F anode to improve its lithium‐storage performance between 3 and 0.01 V. Morphological observations reveal that the MoS2‐modified C/LiVPO4F particles (M‐LVPF) are wrapped by an amorphous carbon as interlayer and layered MoS2 as external surface. Charge–discharge tests show that M‐LVPF delivers a high reversible capacity of 308 mAh g−1 at 50 mA g−1. After 300 cycles at 1.0 A g−1, a capacity retention of 98.7 % is observed. Moreover, it exhibits high rate capability with a specific capacity of 199 mAh g−1 at 1.6 A g−1. Electrochemical impedance spectroscopy tests indicate that the lithium‐ion diffusion and charge‐exchange reaction at the surface of M‐LVPF are greatly enhanced. First‐principles calculations for the MoS2 (001)/C/LiVPO4F (010) system demonstrate that the absorption of MoS2 on C/LiVPO4F is exothermic and spontaneous and that the electron transfer at the MoS2‐absorbed C/LiVPO4F surface is enhanced.
High Performance and Cost‐Effective Direct Methanol Fuel Cells: Fe‐N‐C Methanol‐Tolerant Oxygen Reduction Reaction Catalysts
Authors: Sebastián David , Serov Alexey , Artyushkova Kateryna , Gordon Jonathan , Atanassov Plamen , Aricò Antonino S. , Baglio Vincenzo
Published: July 2016

Direct methanol fuel cells (DMFCs) offer great advantages for the supply of power with high efficiency and large energy density. The search for a cost‐effective, active, stable and methanol‐tolerant catalyst for the oxygen reduction reaction (ORR) is still a great challenge. In this work, platinum group metal‐free (PGM‐free) catalysts based on Fe‐N‐C are investigated in acidic medium. Post‐treatment of the catalyst improves the ORR activity compared with previously published PGM‐free formulations and shows an excellent tolerance to the presence of methanol. The feasibility for application in DMFC under a wide range of operating conditions is demonstrated, with a maximum power density of approximately 50 mW cm−2 and a negligible methanol crossover effect on the performance. A review of the most recent PGM‐free cathode formulations for DMFC indicates that this formulation leads to the highest performance at a low membrane–electrode assembly (MEA) cost. Moreover, a 100 h durability test in DMFC shows suitable applicability, with a similar performance–time behavior compared to common MEAs based on Pt cathodes.
The Role of “Momentum Removal” in Divertor Detachment
Authors: Kukushkin A. S. , Pacher H. D.
Published: July 2016

The role of “momentum removal” (the drag force on the plasma ion flow) in divertor detachment is considered and analysed in detail. This analysis of the 2D modelling results shows that the drag force cannot reduce the power and particle flux to the target directly. However, it is essential for creating the conditions for efficient radiation and volumetric plasma recombination, which in turn do the job. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of PSI on Momentum Input to Plasma‐Facing Material Surfaces
Authors: Takamura S. , Uesugi Y. , Kuwabara T.
Published: July 2016

A comprehensive formulation for momentum input to plasma‐facing material surfaces is newly tried, including a momentum increase due to ion reflection on surfaces with a new definition of momentum reflection coefficient, a momentum due to reaction of evaporated atoms, an increase due to physical sputtering, and the effect of plasma flow. Experimentally observed momentum input is evaluated with a simple formula as well as a mechanical cantilever model. In addition, the measurement with dial tension gauge in off‐plasma condition gives a total force, the value of which is compared with the above two estimations. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transvenous stimulation of the phrenic nerve for the treatment of central sleep apnoea: 12 months' experience with the remedē® System
Authors: Jagielski Dariusz , Ponikowski Piotr , Augostini Ralph , Kolodziej Adam , Khayat Rami , Abraham William T.
Published: July 2016

Aims

Patients with central sleep apnoea (CSA) often have poor quality of life and are at increased risk of morbidity and mortality. This study sought to evaluate the 12‐month clinical outcomes of patients with CSA treated with unilateral transvenous phrenic nerve stimulation in the prospective, multicentre, non‐randomized remedē® System pilot study.

Methods and results

Forty‐seven patients with CSA were treated with the remedē® System (Respicardia Inc., Minnetonka, MN, USA) for a minimum of 3 months. Sleep‐disordered breathing parameters were evaluated by polysomnography (PSG) at 3, 6, and 12‐month follow‐up. Sleep symptoms and quality of life were also evaluated. Forty‐one patients completed all follow‐up PSGs and were included in the analysis. At 12 months, there was sustained improvement compared with baseline in the apnoea–hypopnoea index (49.9 ± 15.1 vs. 27.5 ± 18.3 events/h, P < 0.001) and central apnoea index (28.2 ± 15.0 vs. 6.0 ± 9.2 events/h, P < 0.001). Sustained improvement in the oxygen desaturation index (46.1 ± 19.1 vs. 26.9 ± 18.0 events/h, P < 0.001), rapid eye movement sleep (11.4 ± 6.1% vs. 17.1 ± 8.0%, P < 0.001), and sleep efficiency (69.3 ± 16.9% vs. 75.6 ± 17.1%, P = 0.024) were also observed. There were also continued favourable effects on sleepiness and quality of life. Three deaths unrelated to remedē® System therapy and five serious adverse events occurred over 12 months of follow‐up.

Conclusion

The present study demonstrates that in patients with CSA, unilateral transvenous phrenic nerve stimulation is associated with sustained improvement in key sleep parameters, sleep symptoms, and quality of life over 12 months of follow‐up.
Topological Evolution in Mercury(II) Schiff Base Complexes Tuned through Alkyl Substitution – Synthesis, Solid‐State Structures, and Aggregation‐Induced Emission Properties
Authors: Dong Yu‐Wei , Fan Rui‐Qing , Wang Xin‐Ming , Wang Ping , Zhang Hui‐Jie , Wei Li‐Guo , Song Yang , Du Xi , Chen Wei , Yang Yu‐Lin
Published: July 2016

From two series of Schiff base ligands, (E)‐N‐(pyridine‐2‐yl)(CMe=NPhR) and (E)‐N‐(pyridine‐2‐yl)(CH=NPhR) [R = H, L1a, L1b; 2‐CH3, L2a, L2b; 4‐CH3, L3a, L3b; 2,6‐(CH3)2, L4a, L4b; 2,6‐(C2H5)2, L5a, L5b; 2,6‐(i‐C3H7)2, L6a, L6b; 2,4,6‐(CH3)3, L7a, L7b], fourteen mercury(II) complexes, namely, Hg1a–Hg7a and Hg1b–Hg7b were synthesized. Their structures were established by single‐crystal X‐ray diffraction, and they were physically characterized by 1H and 13C NMR spectroscopy, ESI‐MS, FTIR spectroscopy, elemental analysis (EA), and powder XRD (PXRD). The crystal structures indicate that the position and type of substituent can directly influence the formation of 1D → 3D supramolecular metal–organic frameworks through C–H···Cl and π–π interactions. Complexes Hg1a–Hg7a and Hg1b–Hg7b display deep blue emissions at λ = 401–428 nm in acetonitrile solution and light blue emissions at λ = 443–494 nm in the solid state. It is worth noting that Hg1a, Hg3a, Hg1b, and Hg3b exhibit good aggregation‐induced emission (AIE) properties in CH3CN/H2O solutions.
Field‐Induced Single‐Ion‐Magnetic Behavior of Octahedral CoII in a Two‐Dimensional Coordination Polymer
Authors: Mondal Amit Kumar , Khatua Sajal , Tomar Kapil , Konar Sanjit
Published: July 2016

Two 2D coordination polymers have been synthesized by employing V‐shaped flexible terpyridine‐based ligand L [L = 4′‐(4‐methoxyphenyl)‐4,2′:6′,4′′‐terpyridine] as linker and MII (M = CoII, FeII) as nodes. Structural analysis of both complexes revealed the formation of a rare [4+4] metallocyclic unit. The extension of these cyclic units into two dimensions gives rise to an interdigitated 2D sheet structure in which the methoxy group of the ligand is oriented above and below the sheet to form crests and troughs. Detailed dc and ac magnetic susceptibility measurements revealed the field‐induced slow magnetic relaxation behavior of the magnetically isolated six‐coordinate CoII center with easy‐plane magnetic anisotropy. The effective energy barrier (Ueff) was found to be 36.9 K, which is the highest value reported so far for 2D CoII‐based single‐ion magnets.
ZnO@ZIF Core–Shell Single Crystals Formed by in Situ Conversion of ZnO Particles
Authors: Sun Ying , Zhang Qing , Xu Xiaona , Zhang Lin , Wu Zhengming , Guo Jun , Lu Guang
Published: July 2016

We herein report the formation of two types of ZnO@ZIF core–shell single crystals through the in situ conversion of ZnO particles. The hybrid core–shell single crystals of ZIF‐8 and ZIF‐71 were obtained by treating 95 nm ZnO particles with 2‐methylimidazole and 4,5‐dichloroimidazole, respectively, under the optimized experimental conditions. The ZnO cores are spherical, caplike and noncentrally encapsulated in the ZIF crystals. The effects of the reaction solvent, ligand concentration and ZnO particle size were investigated, and the results show that the single‐site heterogeneous nucleation and growth of ZIF on the template surfaces are the key to the formation of ZnO@ZIF core–shell single crystals.
Sulfur versus Dioxygen: Dinuclear (Trisulfido)copper Complexes
Authors: Wern Miriam , Hoppe Tobias , Becker Jonathan , Zahn Stefan , Mollenhauer Doreen , Schindler Siegfried
Published: July 2016

In contrast to dinuclear (disulfido)copper complexes related trisulfido compounds have not been reported so far. Here we describe two new complexes of this type, [Cu2(tmpa)2S3](SbF6)2 {tmpa = tris(2‐pyridylmethyl)amine} and [Cu2(tet b)2S3](OTf)2 (tet b = rac‐5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane), that have been investigated and could be structurally characterized. Furthermore, the reactivity of these complexes towards dioxygen showed that the corresponding (peroxido)copper complexes formed. Depending on the stoichiometric conditions (excess of sulfur) mononuclear end‐on (sulfido)copper complexes were detected spectroscopically. DFT calculations were performed and supported the experimental results.
Formation of π‐Cation Radicals in Highly Deformed Copper(II) Porphyrins: Implications for the Distortion of Natural Tetrapyrrole Macrocycles
Authors: Zhou Zaichun , Tang Min , Liu Qiuhua , Zhang Xi , Zhou Xiaochun
Published: July 2016

Five copper(II)–porphyrin cages were synthesized with Cu ions as a template. CuII ions can be activated and stabilized as π‐cation radicals in a highly deformed cage complex by electron transition from the metal ion to the π‐a1u orbital of the ring. This study indicates that the activation of the unpaired electron of the CuII ion only requires the contraction of the core, because the excitation of the electron and the stability of the activated electron are related to the cage features of the molecule. The cation radical will drive the formation of CuIII ions at lower voltages, and these results aid the understanding of the roles of macrocyclic distortion and distal pockets in heme chemistry. The electronic structures of five copper(II) complexes were analyzed through electron paramagnetic resonance spectroscopy, UV/Vis spectroscopy, and electrochemical methods, and selected structural parameters were obtained directly from their crystal structures.
Template Synthesis of Alkyl‐Substituted Metal Isocorroles
Authors: Hoffmann Martin , Cordes Birte , Kleeberg Christian , Schweyen Peter , Wolfram Benedikt , Bröring Martin
Published: July 2016

Invited for the cover of this issue is the group of Martin Bröring from the Technical University Braunschweig, Germany. The cover image shows the metal‐ion‐templated macrocyclization of linear tetrapyrroles for the synthesis of non‐aromatic porphyrinoids.
Filling Some Blanks in a Divergent Approach to Gabosines: Enantioselective Synthesis of (–)‐Epiepoxydon, (+)‐Phyllostine, (–)‐Gabosine D, and (–)‐Gabosine E
Authors: Fresneda Miguel Ángel , Alibés Ramon , Bayón Pau , Figueredo Marta
Published: July 2016

The levorotatory enantiomers of gabosines D and E were synthesized through a divergent approach that could equally well be applied to the synthesis of the dextrorotatory enantiomers, which have been isolated from natural sources. The approach relies on an initial desymmetrization of p‐methoxyphenol, followed by an enzymatic resolution that separately provides the two enantiomers of synthon 3. This versatile synthon can be further transformed into the diverse polyoxygenated cyclohexane target molecules. Key steps in the synthesis of (–)‐gabosines D and E from (4R,6S)‐3 are the stereoselective hydroxymethylation at the α‐carbonyl position leading to (+)‐4, and the subsequent reagent‐controlled epoxidation of the carbon–carbon double bond. A branching in the sequence also allowed the synthesis of the anhydrogabosines (–)‐epiepoxydon and (+)‐phyllostine.
Efficient O‐Acylation of Alcohols and Phenol Using Cp2TiCl as a Reaction Promoter
Authors: Durán‐Peña María Jesús , Botubol‐Ares José Manuel , Hanson James R. , Hernández‐Galán Rosario , Collado Isidro G.
Published: July 2016

A method has been developed for the conversion of primary, secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed for these transformations.
Imidazolium and Potassium Hydrogen Carbonate Salts as Ecofriendly Organocatalysts for Oxazolidinone Synthesis
Authors: Fournier Antoine H. , de Robillard Guillaume , Devillers Charles H. , Plasseraud Laurent , Andrieu Jacques
Published: July 2016

Although oxazolidinones are valuable intermediate compounds for industrial applications, no synthetic method is suitable for their production on a large scale owing to the use of reagents/catalysts that are hazardous or toxic to human health or ecotoxic for the environment. In this manuscript, we describe new and efficient catalysts, that is, the nontoxic hydrogen carbonate anion in combination with a potassium or diisobutylimidazolium ([iBu2IM]) countercation, for the conversion of β‐amino alcohols into cyclic oxazolidinones in high yields of 69 to 90 %. Depending on the catalytic conditions, both catalysts could be easily recovered from the crude reaction products and reused several times without a decrease in their catalytic performance. Furthermore, the imidazolium cation is a renewable catalyst, because its preparation requires less than 10 % of carbon fossil sources.
Synthesis of 5,6‐Dihydropyrazolo[5,1‐a]isoquinoline and Ethyl (Z)‐3‐Acetoxy‐3‐tosylpent‐4‐enoate through Tertiary‐Amine‐Catalyzed [3+2] Annulation
Authors: Lei Yu , Xing Jiao‐Jiao , Xu Qin , Shi Min
Published: July 2016

The 1,4‐diazabicyclo[2.2.2]octane (DABCO) catalyzed divergent [3+2] annulation of C,N‐cyclic azomethine imines with δ‐acetoxyallenoates was developed; 5,6‐dihydropyrazolo[5,1‐a]isoquinolines and ethyl (Z)‐3‐acetoxy‐3‐tosylpent‐4‐enoates were afforded in moderate to good yields in a one‐pot manner under mild conditions. This annulation reaction provides a highly efficient method to construct dinitrogen‐fused heterocycles and ethyl (Z)‐3‐acetoxy‐3‐tosylpent‐4‐enoates at the same time.
Electrochemical and Surface Analysis Studies on the Carbon Dioxide Corrosion of X‐65 Carbon Steel
Authors: Alam Muhammad Tanzirul , Chan Emilyn Wai Lyn , De Marco Roland , Huang Yanliang , Bailey Stuart
Published: July 2016

A comprehensive study of the CO2 corrosion of carbon steel (X‐65) at low partial pressures of CO2 is reported in this paper. Field emission scanning electron microscopy (FESEM), Raman spectroscopy (RS), synchrotron radiation‐grazing incidence X‐ray diffraction (SR‐GIXRD), and electrode kinetic studies have confirmed that chukanovite, magnetite and siderite are the main corrosion products at low partial pressures of CO2. Chukanovite forms predominantly in the presence of CO2, while magnetite was found to be the major corrosion product in the absence of CO2, although the majority of previous work based on conventional ex‐situ materials characterization techniques has implied that siderite is the main corrosion product. Here, it is shown that the nature of corrosion products is strongly dependent on the experimental conditions at low pressures of CO2, which has not been elucidated in previous studies. Accordingly, this study has made a significant contribution to identifying the true nature of corrosion scales formed at low partial pressures of CO2 allowing the development of effective anti‐corrosive agents for the control and prevention of carbon steel corrosion at low CO2 partial pressures.
Urea‐Based Fuel Cells and Electrocatalysts for Urea Oxidation
Authors: Xu Wei , Wu Zucheng , Tao Shanwen
Published: July 2016

Urea is a new member of hydrogen‐storage materials for low‐temperature fuel cells. It avoids issues of toxicity and safety compared to NH3 and hydrazine. The main limitation of urea‐based fuel cells is their relatively low power densities due to the sluggish anode reactions. Rapid advances in nanocatalysts used for urea electro‐oxidation have been achieved in lowering overpotential and improving activity. Urine, as a natural resource of urea, is also an environmental pollutant. Most technologies of treating urine with self‐generation electricity are based on microbial fuel cells. However, microbes are only able to utilize the organic substrates rather than urea in urine. Chemical fuel cells in contrast directly oxidize urea to nitrogen gas, removing it from urine. Thus, urea‐based fuel cells have been used as an alternative method to treat urine. In this Minireview, the progress in urea‐based fuel cells and electrocatalysts for urea oxidation is reviewed.
Heat Transfer from Confined Contaminated Bubbles to Power‐Law Liquids at Low to Moderate Reynolds and Prandtl Numbers
Authors: Kishore Nanda , Nalajala Venkata S
Published: July 2016

In this work combined effects of the wall confinement and the power‐law fluid viscosity on the heat transfer phenomena of contaminated bubbles are reported through numerical investigations. In order to delineate the effect of insoluble surfactants the spherical stagnant cap model is adopted. The solver is thoroughly validated by comparing the present results with their literature counterparts. Further, extensive new results are reported on the isotherm contours and average Nusselt numbers of confined contaminated bubbles in the range of conditions: Reynolds number, Re: 0.1 to 200; Prandtl number, Pr: 1 to 1000; power‐law index, n: 0.2 to 1.6 and stagnant cap angle, α: 0 to 180°. Briefly, results are indicative of the following observations. The temperature contours are increasingly sucked towards the rear end of the bubble with the increase in Reynolds number and/or with the increase in Prandtl number and/or with the decrease in power‐law index and/or with the decrease in stagnant cap angle. At Re ≤ 1 and Pr ≤ 10, the average Nusselt number is almost independent of power‐law indices and the stagnant cap angle. For Pe > 10, regardless of values of the confinement ratio and Reynolds number, for α ≥ 60 the average Nusselt number decreases with an increasing stagnant cap angle whereas for α < 60 the effect of contamination is found to be insignificant. The increase in the average Nusselt number with an increasing confinement ratio would occur only at moderate to large values of Reynolds and Prandtl numbers regardless of the values of the power‐law index provided that α ≥ 60°.
Leiodermatolide, a novel marine natural product, has potent cytotoxic and antimitotic activity against cancer cells, appears to affect microtubule dynamics, and exhibits antitumor activity
Authors: Guzmán Esther A. , Xu Qunli , Pitts Tara P. , Mitsuhashi Kaoru Ogawa , Baker Cheryl , Linley Patricia A. , Oestreicher Judy , Tendyke Karen , Winder Priscilla L. , Suh Edward M. , Wright Amy E.
Published: July 2016

Pancreatic cancer, the fourth leading cause of cancer death in the United States, has a negative prognosis because metastasis occurs before symptoms manifest. Leiodermatolide, a polyketide macrolide with antimitotic activity isolated from a deep water sponge of the genus Leiodermatium, exhibits potent and selective cytotoxicity toward the pancreatic cancer cell lines AsPC‐1, PANC‐1, BxPC‐3, and MIA PaCa‐2, and potent cytotoxicity against skin, breast and colon cancer cell lines. Induction of apoptosis by leiodermatolide was confirmed in the AsPC‐1, BxPC‐3 and MIA PaCa‐2 cells. Leiodermatolide induces cell cycle arrest but has no effects on in vitro polymerization or depolymerization of tubulin alone, while it enhances polymerization of tubulin containing microtubule associated proteins (MAPs). Observations through confocal microscopy show that leiodermatolide, at low concentrations, causes minimal effects on polymerization or depolymerization of the microtubule network in interphase cells, but disruption of spindle formation in mitotic cells. At higher concentrations, depolymerization of the microtubule network is observed. Visualization of the growing microtubule in HeLa cells expressing GFP‐tagged plus end binding protein EB‐1 showed that leiodermatolide stopped the polymerization of tubulin. These results suggest that leiodermatolide may affect tubulin dynamics without directly interacting with tubulin and hint at a unique mechanism of action. In a mouse model of metastatic pancreatic cancer, leiodermatolide exhibited significant tumor reduction when compared to gemcitabine and controls. The antitumor activities of leiodermatolide, as well as the proven utility of antimitotic compounds against cancer, make leiodermatolide an interesting compound with potential chemotherapeutic effects that may merit further research.
Homochirality of Organic Matter – Objective Law or Curious Incident?
Authors: Davankov Vadim A.
Published: July 2016

Of the many hypotheses on the origin of biological homochirality on the Earth, the combination of the notion of subatomic particles composing a homochiral pool of primary matter, on the one hand, with the suggestion of the synthesis of chiral organic molecules in the plasma torch generated by super‐high‐velocity impacts (SHVI) of meteorites, on the other hand, was chosen as the working assumption.
Dithiothreitol (DTT) rescues mitochondria from nitrofurantoin‐induced mitotoxicity in rat
Authors: Omidi Mahmoud , Niknahad Hossein , Mohammadi‐Bardbori Afshin
Published: July 2016

Nitrofurantoin (N‐(5‐nitro‐2‐furfurylidine) 1‐amino‐hydantoine; NIT) is mainly used for the treatment of acute urinary tract infections. However, its administration can be associated with liver failure or cirrhosis. The aim of this study was to determine whether NIT is a mitochondrial toxicant, if so, what mechanism(s) is involved.

The rat liver mitochondria were isolated and treated with different doses of NIT alone or in combination with a reagent of choice for protecting thiol groups, dithiothreitol (DTT). Several mitochondrial parameters, including succinate dehydrogenase activity (also called 3‐(4,5‐dimethylthiazol‐2‐yl) 2,5‐diphenyl tetrazolium bromide assay), lipid peroxidation, superoxide dismutase activity, Reduced glutathione (GSH), and oxidized glutathione (GSSG), and GSSG (oxidized glutathione) levels were determined. The results from this study showed that simultaneous treatment of mitochondria with NIT and DTT significantly reduces the toxicity. Here, we provide evidence that mitochondrial dysfunction followed by depletion of reduced glutathione can be reversed by DTT administration.
A118G Polymorphism in μ‐Opioid Receptor Gene and Interactions with Smoking and Drinking on Risk of Oesophageal Squamous Cell Carcinoma
Authors: Xu Xinfang , Mao Boneng , Wu Lingdong , Liu Lei , Rui Juping , Chen Guochang
Published: July 2016

Aim

To investigate the single nucleotide polymorphism (SNP) of A118G and its interaction with smoking and drinking on oesophageal squamous cell carcinoma (ESCC) risk.

Methods

A total of 960 subjects (545 males and 415 females) with a mean age of 58.1 ± 13.4 years were selected, including 490 ESCC patients and 470 normal control subjects. A logistic regression model was used to examine the association between A118G and ESCC and its interaction with A118G and current smoking and drinking. The odds ratio (OR) and 95% confident interval (95%CI) were calculated.

Results

The frequency for the A allele of A118G was significantly higher in ESCC cases, OR (95%CI) = 1.22 (1.08–1.59). Logistic regression analysis showed a significant association between the A allele in A118G and increased ESCC risk. The ESCC risk was significantly higher in carriers of the A allele of the A118G polymorphism than those with GG (AG + AA vs. GG, adjusted OR (95%CI) = 1.20 (1.05–1.53)). We found that current smokers with AG or AA of the A118G genotype have the highest ESCC risk compared with never smokers with a GG genotype; the OR (95%CI) was 2.57 (1.66–3.33). Current drinkers with AG or AA of the A118G genotype have the highest ESCC risk compared with not currently drinking subjects with the GG genotype, OR (95%CI) = 2.36 (1.47–3.25), after adjusting for covariates.

Conclusion

The A allele of A118G and ESCC and additional interaction between the A allele of A118G and smoking or drinking were associated with increased ESCC risk.
An expedited approach for sustained delivery of bone morphogenetic protein‐7 to bone defects using gene activated fragments of subcutaneous fat
Authors: Betz Volker M. , Betz Oliver B. , Rosin Tom , Keller Alexander , Thirion Christian , Salomon Michael , Manthey Suzanne , Augat Peter , Jansson Volkmar , Müller Peter E. , Rammelt Stefan , Zwipp Hans
Published: July 2016

Background

Delivery of bone morphogenetic protein‐7 (BMP‐7) to bone defects can be improved by applying gene transfer methods. However, traditional ex vivo gene therapy approaches are cumbersome and costly, requiring the extraction and culturing of cells. Therefore, we evaluated a novel, expedited ex vivo BMP‐7 gene transfer technology based on the use of fragments of subcutaneous fat tissue.

Methods

We created 5‐mm mid‐femoral bone defects in the right femora of 23 male, syngeneic Fischer 344 rats. Adipose tissue was harvested from the subcutaneous fat depot of two donor rats. Bone defects were treated with either unmodified fat (control group) or adenovirally BMP‐7 transduced fat fragments (treatment group). Healing of bone defects was assessed by radiographs, microcomputed tomography (μCT) and histology at 6 weeks after the implantation of fat tissue fragments.

Results

Radiographs, μCT‐imaging and histology revealed relevant bone formation in six out of 10 rats treated with BMP‐7 activated fat grafts. Two of the defects were bridged. By contrast, femora of the control group receiving unmodified fat did not display signs of osseous healing. BMP‐7 gene activated fat treatment led to a significantly higher bone volume (11.18 ± 9.48 mm3) than treatment with unmodified fat grafts (3.19 ± 1.68 mm3) (p = 0.008).

Conclusions

Implantation of BMP‐7 gene activated fat tissue fragments can elicit regeneration of large bone defects in rats and could become a clinically expeditious strategy for in vivo bone tissue engineering. However, gene expression must be improved in order to reliably induce osseous bridging of critical‐size bone defects. Copyright © 2016 John Wiley & Sons, Ltd.
Facile Synthesis of Phenanthridinone Alkaloids via Suzuki–Miyaura Cross‐coupling
Authors: Kuwata Yoshiyuki , Sonoda Motohiro , Tanimori Shinji
Published: July 2016

Phenanthridinone alkaloids crinasiadine 1 and N‐alkylcrinasiadines 6, 7, 8, 9, 10 have been synthesized based on palladium‐catalyzed tandem C–C and C–N bond formation starting from 2‐aminophenylboronic acid and 2‐bromobenzoate in short steps. Related alkaloids, 5,6‐dihydrobicolorine 2, trisphaeridine 3, and bicolorine 12 have also been synthesized.
P2 receptors, microglial cytokines and chemokines, and neuropathic pain
Authors: Tsuda Makoto
Published: July 2016

Neuropathic pain is a debilitating chronic pain and represents a major clinical challenge. The molecular and cellular mechanisms underlying its development and maintenance are not fully understood but involve abnormal excitability in the dorsal horn of the spinal cord. A growing body of evidence has shown that this aberrant excitability may be a consequence not merely of changes in neurons but rather of multiple alterations in microglia, which are resident macrophages in the central nervous system. This review highlights recent advances in our understanding of the mechanisms that underlie neuropathic pain caused by peripheral nerve injury, with a specific focus on purinergic signaling in spinal cord microglia. This provides convincing evidence for a crucial role for microglial purinergic signaling in the pathogenesis of neuropathic pain, and P2 receptors may be potential therapeutic targets for managing neuropathic pain. © 2016 Wiley Periodicals, Inc.
Low‐frequency variability and trends in centennial precipitation stations in southern South America
Authors: Saurral Ramiro I. , Camilloni Inés A. , Barros Vicente R.
Published: July 2016

Southern South America (SSA), considered as the continental region south of 20°S, has experienced significant precipitation variability and trends in the last decades. This article uses monthly quality‐controlled precipitation data from rainfall stations with continuous observations during at least 100 years to quantify long‐term trends as well as interannual‐to‐centennial variability. Several statistical methods are applied to the data, primarily to detect jumps and look for changes due to relocation of the gauge stations, as well as to identify significant trends. Most of the regions have registered an increase in annual rainfall, largely attributable to changes in the warm season. On the other hand, during winter most stations in Argentina and Brazil do not have significant trends, although eastern Patagonia registered an increase in precipitation and Chile, a marked decrease in rainfall.

In order to look into the physical mechanisms behind the observed variability, the changes in mean sea level pressure and precipitable water are quantified for different sub‐periods. Also explored is the variability related to the Hadley cell width and strength over the region around SSA. Results show that the Hadley cell has shrunk and shifted towards the equator in winter over the area, which has caused an enhancement of the sinking motion over much of Argentina, Chile and Brazil, while likely increasing the baroclinicity (and associated precipitation) over Patagonia. In summer, the strength of the subsidence decreased and this was associated with an increase of the low‐level moisture advection, favouring more rainfall. The observational evidence presented here suggests that the zonal asymmetry in the change of the Hadley cell position over SSA could be linked to the presence of the Andes Cordillera.
Influence of Sesbania Brown Manuring and Rice Residue Mulch on Soil Health, Weeds and System Productivity of Conservation Rice–Wheat Systems
Authors: Nawaz Ahmad , Farooq Muhammad , Lal Rattan , Rehman Abdul , Hussain Tasawar , Nadeem Asif
Published: July 2016

The sustainability of rice–wheat cropping system (RWCS) is threatened by increasing labor, water, and energy crises in the region. Conservation RWCSs offers an ecofriendly alternate option. This study was aimed to evaluate the impact of sesbania brown manuring in direct‐seeded aerobic rice (DSAR) and of rice residue mulch in no‐tilled wheat (NTW) on soil health, weed dynamics and system productivity. The experiment was composed of five RWCS systems: (i) DSAR‐NTW; (ii) DSAR + sesbania brown manuring‐NTW; (iii) DSAR‐NTW + rice residue mulch; (iv) puddled transplanted flooded rice (PudTR)‐NTW; and (v) PudTR‐plow‐tilled wheat. Sesbania brown manuring in direct‐seeded rice decreased the weed density and dry biomass 41–56% and 62–75%, respectively, than the sole direct‐seeded rice crop. At rice harvest, better soil health, in terms of total nitrogen (N), soil organic carbon, soil microbial biomass carbon, and soil microbial biomass nitrogen, was noted with DSAR + sesbania brown manuring‐NTW. Rice residue mulch retention in NTW decreased weed density and dry weight by 60 and 69%, respectively, than those under NTW with no mulch. At wheat harvest, highest total N, soil organic carbon, and soil microbial biomass carbon were recorded with DSAR‐NTW + rice residue mulch, followed by DSAR + sesbania brown manuring‐NTW. Overall, NTW grown after DSAR + sesbania brown manuring produced more grain yield than PudTR‐NTW and PudTR‐plow‐tilled wheat systems. In conclusion, sesbania brown manuring in DSAR and residue mulch retention in NTW may be opted to improve soil properties, suppress weeds, and to harvest better grain yield and achieve higher system productivity in conservation RWCSs. Copyright © 2016 John Wiley & Sons, Ltd.
Nucleobase‐Functionalized Supramolecular Micelles with Tunable Physical Properties for Efficient Controlled Drug Release
Authors: Cheng Chih‐Chia , Lin I‐Hong , Chen Jem‐Kun , Liao Zhi‐Sheng , Huang Jyun‐Jie , Lee Duu‐Jong , Xin Zhong
Published: July 2016

Complementary nucleobase‐functionalized polymeric micelles, a combination of adenine‐thymine (A‐U) base pairs and a blend of hydrophilic–hydrophobic polymer pairs, can be used to construct 3D supramolecular polymer networks; these micelles exhibit excellent self‐assembly ability in aqueous solution, rapid pH‐responsiveness, high drug loading capacity, and triggerable drug release. In this study, a multi‐uracil functionalized poly(ε‐caprolactone) (U‐PCL) and adenine end‐capped difunctional oligomeric poly(ethylene glycol) (BA‐PEG) are successfully developed and show high affinity and specific recognition in solution owing to dynamically reversible A‐U‐induced formation of physical cross‐links. The U‐PCL/BA‐PEG blend system produces supramolecular micelles that can be readily adjusted to provide the desired critical micellization concentration, particle size, and stability. Importantly, in vitro release studies show that doxorubicin (DOX)‐loaded micelles exhibit excellent DOX‐encapsulated stability under physiological conditions. When the pH value of the solution is reduced from 7.4 to 5.0, DOX‐loaded micelles can be rapidly triggered to release encapsulated DOX, suggesting these polymeric micelles represent promising candidate pH‐responsive nanocarriers for controlled‐release drug delivery and pharmaceutical applications.

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Polymeric Drift Control Adjuvants for Agricultural Spraying
Authors: Lewis Reece W. , Evans Richard A. , Malic Nino , Saito Kei , Cameron Neil R.
Published: July 2016

The movement of a pesticide or herbicide to an off‐target site during agricultural spraying can cause injury to wildlife, plants and contamination of surface water. This phenomenon is known as spray drift and can be controlled by spraying during favorable environmental conditions, and by using low drift nozzles and drift control adjuvants (DCAs). Polymeric DCAs are the most common type of DCA and function by increasing the droplet size produced during spraying. There are, however, two main drawbacks of polymeric DCAs; they are prone to mechanical degradation during spraying which reduces their performance and they can produce oversized drops which reduces the efficacy of the spray. In this trend article, existing DCA technology is reviewed including the mechanism through which they function. This then provides a platform for the discussion of novel polymeric architectures which have currently not been applied in DCA formulations.

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Renewable Microspheres Constructed by Methyl Isoeugenol‐Derived Copolymers
Authors: Yong Xueyong , Zhou Jinyong , Zhang Huanyu , Yuan Yunbin , Deng Jianping
Published: July 2016

Biobased polymers have gathered a lot of interest and are currently attracting ever‐increasing attention. However, polymeric microspheres especially those derived from biomasses of small molecules, have not been extensively explored yet. This contribution reports recent exciting success in designing and preparing methyl isoeugenol (MeIE)‐derived renewable microspheres. Owing to the difficulty in homopolymerizing MeIE, it undergoes precipitation copolymerization with maleic anhydride to form the anticipated copolymeric microspheres in a high yield (both cross‐linked and non‐cross‐linked). The copolymers show high heat resistance, and the microspheres can be easily functionalized by taking advantage of the highly reactive anhydride groups. A novel type of cation exchange microspheres is further prepared by transforming the anhydride groups into carboxyl groups through hydrolyzation. The hydrolyzed microspheres demonstrate remarkable adsorption toward Cu2+ (maximum, 300 mg g−1). Accordingly, the microspheres may find practical applications, e.g., as green adsorbents. The established preparing methodology can also be taken for other bio‐phenylpropenes.

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Design of New Cardanol Derivative: Synthesis and Application as Potential Biobased Plasticizer for Poly(lactide)
Authors: Hassouma Fatima , Mihai Iulia , Fetzer Ludivine , Fouquet Thierry , Raquez Jean‐Marie , Laachachi Abdelghani , Ibn Al Ahrach Hicham , Dubois Philippe
Published: July 2016

A novel biobased plasticizer made of cardanol is designed for poly(lactide) (PLA). This cardanol‐derived plasticizer, i.e., methoxylated hydroxyethyl cardanol (MeCard), is synthesized through methoxylation of the double bonds on the side chain of cardanol, and characterized by 1H NMR and mass spectrometry. The plasticization effect of MeCard on the molecular structure, morphology, thermal and mechanical properties of PLA is evaluated and compared to that of a commercial cardanol, i.e., hydroxyethyl cardanol (pCard). The plasticization efficiency of MeCard is demonstrated by a substantial decrease of the glass transition temperature and storage modulus together with a significant increase of the elongation at break as compared to neat PLA. Moreover, MeCard exhibits higher plasticization performance than pCard toward PLA. Such behavior is related to a higher miscibility and compatibility between PLA and MeCard thanks to the methoxylation of the double bonds on the side chain of cardanol as shown by SEM micrographs.

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Extensional Flow‐Induced Dynamic Phase Transitions in Isotactic Polypropylene
Authors: Ju Jianzhu , Wang Zhen , Su Fengmei , Ji Youxin , Yang Haoran , Chang Jiarui , Ali Sarmad , Li Xiangyang , Li Liangbin
Published: July 2016

With a combination of fast extension rheometer and in situ synchrotron radiation ultra‐fast small‐ and wide‐angle X‐ray scattering, flow‐induced crystallization (FIC) of isotactic polypropylene (iPP) is studied at temperatures below and above the melting point of α crystals (Tmα). A flow phase diagram of iPP is constructed in strain rate–temperature space, composing of melt, non‐crystalline shish, α and α&β coexistence regions, based on which the kinetic and dynamic competitions among these four phases are discussed. Above Tmα, imposing strong flow reverses thermodynamic stabilities of the disordered melt and the ordered phases, leading to the occurrence of FIC of β and α crystals as a dynamic phase transition. Either increasing temperature or stain rate favors the competiveness of the metastable β over the stable α crystals, which is attributed to kinetic rate rather than thermodynamic stability. The violent competitions among four phases near the boundary of crystal‐melt may frustrate crystallization and result in the non‐crystalline shish winning out.

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Poly(paraphenylene sulfide) and Poly(metaphenylene sulfide) via Light‐Initiated SRN1‐Type Polymerization of Halogenated Thiophenols
Authors: Heine Niklas B. , Studer Armido
Published: July 2016

In this work, the synthesis of various halogenated thiophenol derivatives is presented. These thiophenols are used as monomers in light‐initiated SRN1‐type radical polymerization reactions. The method provides easy access to industrially relevant poly(paraphenylene sulfide) and poly(metaphenylene sulfide). The influence of the halide leaving group and of other substituents in the thiophenol monomer on the polymerization process is investigated.

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