bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrocatalytic Hydroxylation of Sterols by Steroid C25 Dehydrogenase from Sterolibacterium denitrificans
Authors: Kalimuthu Palraj , Wojtkiewicz Agnieszka M. , Szaleniec Maciej , Bernhardt Paul V.
Published: March 2018

The electrochemically driven catalysis of the complex molybdoenzyme steroid C25 dehydrogenase (S25DH) from the β‐Proteobacterium Sterolibacterium denitrificans is reported. S25DH catalyses the oxygen‐independent regioselective hydroxylation of the tertiary C25 atom of sterols and also their derivatives. Cholest‐4‐en‐3‐one is a native substrate for S25DH, which produces 25‐hydroxycholest‐4‐en‐3‐one as a product of catalytic turnover. Cholecalciferol (vitD3) is also a substrate. S25DH was immobilised on a modified gold working electrode with the co‐adsorbent chitosan. The complexes ferricyanide ([Fe(CN)6]3−) and ferrocenium methanol (FM+) are effective artificial electron acceptors from S25DH and act as mediators of electron transfer between the electrode and the enzyme. 2‐Hydroxypropyl‐β‐cyclodextrin (HPCD) was employed as a sterol solubiliser, in addition to 2‐methoxyethanol. The catalytic activity varied, depending upon the concentration of solubiliser in the reaction mixture. Parallel studies with [Fe(CN)6]3− as a chemical (as opposed to electrochemical) oxidant coupled to HPLC analysis show that S25DH is capable of oxidising both vitD3 and its less stable isomer, pre‐vitD3, and that the former substrate is stabilised by HPCD.
Synthesis and Characterization of Photothermal Osmium Carbolong Complexes
Authors: Lin Qin , Li Shenyan , Lin Jianfeng , Chen Meijin , Lu Zhengyu , Tang Chun , Chen Zhixin , He Xumin , Chen Jiangxi , Xia Haiping
Published: March 2018

Metallacycles with chelating polydentate conjugated‐carbon chain ligands are called carbolong complexes, which are expected to have interesting properties. In this work, the preparation of 12‐carbon carbolong complexes in which all of the coordinated atoms in the equatorial plane are carbon atoms was studied. With the help of the well‐established mechanism, a new approach to prepare coplanar carbolong complexes bearing different organic functional groups was developed by adding different terminal alkynes in sequence. In the presence of HBF4, these coplanar carbolong complexes were converted to η3‐allyl osmapentalene derivatives, which can be produced directly from the reaction of cyclopropaosmapentalene 1 with terminal alkynes in the presence of AgBF4 under anhydrous conditions. This study offers a new route for the preparation of functional osmium carbolong complexes with excellent photothermal properties, which can be used to prepare photothermal materials.
Ligand‐Based Storage of Protons and Electrons in Dihydrazonopyrrole Complexes of Nickel
Authors: Chang Mu‐Chieh , McNeece Andrew J. , Hill Ethan A. , Filatov Alexander S. , Anderson John S.
Published: March 2018

A newly developed dihydrazonopyrrole ligand and corresponding Ni complexes have been synthesized and thoroughly characterized. Electrochemical studies and chemical reactivity tests show that these complexes can reversibly store both electrons and protons, or equivalently H‐atoms, via ligand‐based events. The stored H‐atom equivalent can be transferred to small molecules such as acetonitrile or oxygen. Furthermore, this series of complexes can adopt a variety of different coordination modes. In addition to one e− reactivity, the two e− electrophilic oxidation of phosphines is also demonstrated. Taken together, these results show that dihydrazonopyrrole complexes represent a geometrically and electronically flexible scaffold for controlling the flow of both electrons and protons.
Single‐Molecule Sensing with Nanopore Confinement: From Chemical Reactions to Biological Interactions
Authors: Lin Yao , Ying Yi‐Lun , Gao Rui , Long Yi‐Tao
Published: March 2018

The nanopore can generate an electrochemical confinement for single‐molecule sensing that help understand the fundamental chemical principle in nanoscale dimensions. By observing the generated ionic current, individual bond‐making and bond‐breaking steps, single biomolecule dynamic conformational changes and electron transfer processes that occur within pore can be monitored with high temporal and current resolution. These single‐molecule studies in nanopore confinement are revealing information about the fundamental chemical and biological processes that cannot be extracted from ensemble measurements. In this Concept article, we introduce and discuss the electrochemical confinement effects on single‐molecule covalent reactions, conformational dynamics of individual molecules and host‐guest interactions in protein nanopores. Then, we extend the concept of nanopore confinement effects to confine electrochemical redox reactions in solid‐state nanopores for developing new sensing mechanisms.
Unusually Long‐Wavelength Emissions of Cyclopropanes: New Insight into C−C Bond Homolysis
Authors: Abe Manabu , Kanahara Kousei , Kadowaki Norito , Tan Chun‐Jui , Tsai Hui‐Hsu Gavin
Published: March 2018

Bond homolysis (BHo) is a fundamental concept in chemical‐bonding phenomena. To date, research studies on the BHo concept have provided crucial information for understanding the nature of chemical bonding and reactions. Two potential‐energy minima, a σ‐bonding isomer and a singlet‐diradical isomer, have been known to exist in carbon–carbon BHo. Herein, a third isomer, that is, a puckered singlet diradical exhibiting unstructured long‐wavelength fluorescence beyond 460 nm, was first observed in the excited states of 1,4‐diarylbicyclo[2.1.0]pentane derivatives. The careful selection of appropriate substituents in the bicyclic structures enabled direct spectral detection. State‐of‐the‐art ab initio quantum chemical calculations quantitatively reproduced the experimental observations. This new finding provides new insight into carbon–carbon bond‐breaking and ‐forming processes.
Therapeutic Nanoreactors as In Vivo Nanoplatforms for Cancer Therapy
Authors: Mukerabigwi Jean Felix , Ge Zhishen , Kataoka Kazunori
Published: March 2018

Therapeutic nanoreactors have been proposed as nanoplatforms to treat diseases through in situ production of therapeutic agents. When this treatment strategy is applied in cancer therapy, it can efficiently produce highly toxic anticancer drugs in situ from low‐toxic prodrugs or some biomolecules in tumor tissues, which can maximize the therapeutic efficacy with a significantly low systemic toxicity. An ideal therapeutic nanoreactor can provide the reaction space, protect the loaded fragile catalysts, target the desired pathological site, and be selectively activated. In this minireview, we highlight the recent advances concerning the applications of therapeutic nanoreactors as in vivo nanoplatforms particularly in cancer therapy. Herein, the therapeutic nanoreactors are discussed on the basis of treatment strategies and various nanoparticles. Specifically, the treatment strategies of nanoreactors including single enzyme, single enzyme with chemodrugs, and multienzymes, as well as varying types of engineered nanoparticle‐loaded active catalysts, primarily including liposomes, polymersomes, polymeric micelles, inorganic nanoparticles, and metal–organic framework (MOF) architectures, are documented and briefly discussed. Finally, we elucidate the current challenges to be addressed toward further development and translation into clinical applications of these therapeutic nanoreactors in cancer therapy.
Synthesis of Benzofuranones via Malonates Desymmetrization: Yield Increase by the Portion‐wise Addition of Quinones
Authors: Puglisi Antonio , Giustini Chiara , Ricucci Angela , Perotti Elisa , Massaro Luca , Morra Diego , Ciucci Flavia , Zucchet Alessio , Antenucci Achille , Moliterno Mauro , Placidi Simone , Sciubba Fabio , Galantini Luciano , Salvio Riccardo , Bella Marco
Published: March 2018

The organocatalyzed addition of several malonates to 1,4‐benzoquinones affords benzofuranones bearing a quaternary stereocenter with good enantioselectivity. This reaction is an intramolecular desymmetrization since it proceeds through the formation of an arylated achiral malonate that cyclizes to give the reaction product. The addition rate of the quinone dramatically affects the reaction yield which was originally low. The yield was considerably increased, in some cases, from less than 20 % to over 95 %, by adding the quinone in portions rather than at once, keeping similar enantioselectivity. A possible rationalization for the preferential formation of the indicated enantiomer has been investigated by DFT calculations.
Limitations of Steric Bulk: Towards Phospha‐germynes and Phospha‐stannynes
Authors: Hinz Alexander , Goicoechea Jose M.
Published: March 2018

The use of bulky aryl(silyl)amides (R) as substituents for the stabilisation of phospha‐germynes and phospha‐stannynes (R−Ge≡P and R−Sn≡P, respectively) is described. Such species can be transiently generated by photolysis of the phosphaketene precursors (RE(PCO); E=Ge, Sn). Utilisation of bulky amides R1 and R2 (R1=Ar**NSi(OtBu)3, where Ar**=2,6‐bis[bis(4‐tert‐butylphenyl)methyl]‐4‐methylphenyl; R2=Ar***NSi(iPr)3, where Ar***=2,6‐bis[bis(3,5‐di‐tert‐butylphenyl)methyl]‐4‐methylphenyl) facilitates the formation of diphosphene‐type dimers, [(RGe)P]2 and [(RSn)P]2. In an effort to circumvent dimerisation, the bulkier R3 substituent (R3=Ar***NSi(4‐tert‐butylphenyl)3) was employed in an analogous series of experiments. This affords cyclic germylenes and stannylenes due to insertion of the terminal phosphide into Si−C bonds of the R3 substituent, which in case of the stannylene could act as a trap for another R3−Sn≡P moiety. All attempts to isolate terminal phosphide species were unsuccessful due to the reactivity of such compounds towards the organic periphery of the bulky amides, highlighting the limitations of highly sterically demanding functionalities.
Ferrocenyl Phthalocyanine as Donor in Non‐Poly(3‐hexylthiophen‐2,5‐diyl) Bulk Heterojunction Solar Cell
Authors: Nar Ilgın , Atsay Armağan , Altındal Ahmet , Hamuryudan Esin , Koçak Makbule B. , Gül Ahmet
Published: March 2018

Bulk heterojunction (BHJ) solar cells might one day play a vital role in realizing low‐cost and environmentally benign photovoltaic devices. In this work, a BHJ solar cell was designed, based on a hexadeca‐substituted phthalocyanine (FcPc) with ferrocenyl linked to the phthalocyanine ring. Next, we sought to obtain more quantitative information about the usability of this newly synthesized compound as a donor material in BHJ solar cells. Thus, BHJs with the structure of indium tin oxide/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate)/FcPc:[6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) blend/LiF/Al were fabricated and characterized. The effect of blend ratio (0.5–2.0) on the BHJ solar cell parameters was also investigated. Interesting results were obtained in FcPc and the PCBM blend‐based BHJ solar cell under optimized conditions. Our results presented here demonstrate that BHJ devices employing FcPc as a donor has great potential for the development of highly efficient non‐poly(3‐hexylthiophen‐2,5‐diyl) photovoltaic devices.
Colorimetric chiral fluorescent sensors for Eu3+ and sequential enantioselective sensing of malate anion
Authors: Liu Xiaoyan , Wang Peng , Fu Jiaxin , Yao Kun , Chang Yongxin , Xu Kuoxi
Published: March 2018

Novel phenanthroline Schiff base fluorescent sensors L1, L2, and D1 were designed and synthesized. The sensing abilities of the compounds in the presence of metal cations (Li+, Na+, K+, Ag+, Mg2+, Ba2+, Ca2+, Mn2+, Pb2+, Hg2+, Ni2+, Zn2+, Cd2+, Co2+, Cu2+, Cr3+, Fe3+, Fe2+, Al3+, and Eu3+) were studied by UV‐vis and fluorescent spectroscopy. The compounds L1, L2, and D1 could act as Eu3+ ion turn‐off fluorescent sensors based on ligand‐to‐metal binding mechanism in DMSO‐H2O solution (v/v = 1:1, 10 mM Tris, pH = 7.4). Additionally, the L1–Eu3+ and D1–Eu3+ complexes could be applied as turn‐on enantioselective sensors sensing of malate anion isomers with color changes. Furthermore, biological experiments using living PC‐12 cells demonstrated that L1 and D1 had excellent membrane permeability and could be used as effective fluorescent sensors for detecting Eu3+ and malate anion in living cells.
Self‐assembly and chiroptical properties in supramolecular complexes of adenosine phosphates and guanidinium‐bispyrene
Authors: Trévisan Marie , Fossépré Mathieu , Paolantoni Delphine , Rubio‐Magnieto Jenifer , Dumy Pascal , Ulrich Sébastien , Surin Mathieu
Published: March 2018

Supramolecular systems that respond to the hydrolysis of adenosine phosphates (APs) are attractive for biosensing and to fabricate bioinspired self‐assembled materials. Here, we report on the formation of supramolecular complexes between an achiral guanidinium derivative bearing two pyrene moieties, with each of the three adenosine phosphates: AMP, ADP, and ATP. By combining results from circular dichroism spectroscopy and molecular modeling simulations, we explore the induced chirality, the dynamics of the complexes, and the interactions at play, which altogether provide insights into the supramolecular self‐assembly between APs and the guanidinium‐bispyrene. Finally, we identify the chiroptical signals of interest in mixtures of the guanidinium derivative with the three APs in different proportions. This study constitutes a basis to evolve toward a chiroptical detection of the hydrolysis of APs based on organic supramolecular probes.
A Study on Thermodiffusion in Ternary Liquid Mixtures Using Enhanced Molecular Dynamics Algorithm with Experimental Validation
Authors: Mozaffari Seyedeh Hoda , Srinivasan Seshasai , Saghir M. Ziad
Published: March 2018

The objective of this paper is to study thermodiffusive flow in several ternary liquid mixtures of dodecane (nC12)‐1,2,3,4‐tetrahydronaphthalene (THN)‐isobutylbenzene (IBB) for four different compositions at normal pressure and temperature using our recently proposed modified heat exchange (mHEX) algorithm. Predictions from this algorithm are compared with the experimental data obtained in the reduced gravity environment. Comparisons have also been made with the standard heat exchange algorithm to show that the mHEX algorithm is significantly better in predicting the thermodiffusive separation.
A multi‐scenario nonlinear model predictive control approach for robust product transitions
Authors: Flores‐Tlacuahuac Antonio , Gutiérrez‐Limón Miguel Angel
Published: March 2018

Dynamic product transitions are ubiquitous operations in the processing industry. When a first‐principles dynamic model is deployed for real system representation, the calculation of the dynamic optimal trajectory for product transition can be cast as an optimal control problem. A common practice in addressing the solution of optimal product transitions lies in the assumption of free of uncertainty first‐principle models. Ignoring the effect of model uncertainty on product transitions can result in unfeasible dynamic trajectories. In this work, an optimization scenario approach, featuring variable scenario weighting functions, is deployed for assessing the impact of model uncertainty on the control actions such that feasible and optimal transition trajectories are computed featuring minimum deviation from target values. The optimization approach was applied to three nonlinear reaction systems. The results demonstrate that when the variable weighting optimization scenario approach is suitable for approximating model uncertainty, feasible transition trajectories can be calculated at relatively low computational cost (for small or medium scale systems).
Development and characterization of novel combinations of Ce‐Ni‐MFI solids for water gas shift reaction
Authors: Alamolhoda Sarah , Vitale Gerardo , Hassan Azfar , Nassar Nashaat N. , Pereira Almao Pedro
Published: March 2018

In this work, novel catalysts with different low percentages of nickel and cerium (0–3 % g/g) inside a crystalline silica framework were prepared to be tested in catalytic water gas shift reaction (WGSR) at low temperatures. The developed preparation method is distinctive as it does not require the impregnation of metals, drying, and further calcinations steps, and produces the anticipated catalysts in an efficient way. The produced solids were characterized using various characterization methods including XRD, TPR‐TPO, TPD, SEM/EDX, and N2 physisorption. Results indicated that these solids benefit from good reproducibility and ease of mass production. WGSR experiments over the produced solids at 503 K showed that Ce‐MFI solids were inactive at this temperature; however, Ni‐MFI and Ce‐Ni‐MFI solids catalyzed the reaction. At this low temperature, the catalysts containing cerium presented higher activity compared to catalysts with only nickel content. Furthermore, no methane production was observed using these catalysts.
Three different periods of CO2 dissolution into a light crude oil
Authors: Du Fengshuang , Ma Hongze , Gu Yongan
Published: March 2018

In this paper, phase behaviours and mass‐transfer mechanisms of a Bakken light crude oil‐CO2 system are studied. A series of PVT tests of the light crude oil‐CO2 system are conducted to measure CO2 solubilities, oil‐swelling factors, and CO2‐saturated oil densities at different equilibrium pressures and the actual reservoir temperature of Tres = 56.0 °C. Five CO2 diffusion tests in the light crude oil are performed at five different initial test pressures (Pi = 4.1, 5.2, 6.3, 7.7, and 9.0 MPa) and Tres = 56.0 °C by applying the pressure decay method (PDM). The graphical method (GM) is used to analyze the measured test pressure versus time data of each diffusion test and determine CO2 average diffusivity in the light crude oil. It is found that the so‐called density‐driven natural convection can occur in the CO2‐saturated light crude oil as its measured density is much higher than that of the dead light crude oil. Three distinct periods of CO2 dissolution into the light crude oil are identified: the natural convection‐dominated period (I), the transition period, and the molecular diffusion‐dominated period (II). The determined CO2 effective diffusivities (Deff) in Period I and CO2 molecular diffusivities (D) in Period II from the GM are in the ranges of 0.28–1.75 × 10−6 m2/s and 0.87–1.94 × 10−9 m2/s at the initial test pressures of Pi = 4.1–9.0 MPa, respectively. Finally, it is also found that the constant Z‐factor approximation used in the GM may cause a relatively large error in the determination of Deff or D.
Surface treatment with amino acids of porous collagen based scaffolds to improve cell adhesion and proliferation
Authors: Rouabhia Mahmoud , Mighri Nabila , Mao Jifu , Park Hyun Jin , Mighri Frej , Ajji Abdallah , Zhang Ze
Published: March 2018

The purpose of this study was to improve the biocompatibility of glutaraldehyde (GA) cross‐linked chitosan coated collagen scaffold for cartilage tissue regeneration. In order to prevent the potential toxicity of GA, we treated the designed scaffold with either glutamic acid or glycine. Amino acid treated scaffolds were characterized by scanning electron microscopy (SEM) techniques. Afterward, chondrocyte interaction with the composite scaffold was investigated assessing cell adhesion and proliferation using Hoechst staining and MTT cell proliferation assay, respectively. The SEM analyses of the scaffolds’ surface and cross‐section confirmed the adhesion of amino acids on the surface of the scaffolds. We also observed that scaffolds’ porosity was reduced due to the coverage of the pores by chitosan and amino acids, leading to low porosity. The use of amino acid improved the chondrocyte adhesion and proliferation inside the scaffolds’ pores when cells were cultured onto the chitosan‐coated collagen scaffolds. Overall, our in vitro results suggest the use of amino acid to improve the biocompatibility of natural polymer composite scaffold being crosslinked with glutaraldehyde. Such scaffold has improved mechanical properties; biocompatibility thus may be useful for tissue regeneration such as cartilage.
Multiple‐Stimuli Responsive and Tunable Luminescent Supramolecular Assembly by Oligo(p‐phenylvinylene) and Surfactant
Authors: Chen Xu‐Man , Chen Yong , Liu Yu
Published: March 2018

Achieving multicolor photoluminescence under multiple stimuli response based on a single fluorescent compound remains a great challenge. Herein, we report a novel multicolor fluorescent supramolecular assembly, which was constructed from surfactant sodium dodecyl sulfate (SLS) and fluorescent compound 1 bearing a rigid symmetrical acceptor–donor–acceptor structure. The luminescence property of 1/SLS assembly showed the multiple stimuli response towards temperature, cyclodextrin complexation and UV light irradiation, exhibiting the tunable emission wavelengths from 490 nm to 590 nm and the multicolor photoluminescence including cyan, green, yellow and orange. Furthermore, this assembly could be used in light writing owing to the fast fluorescence change within 15 s. These results could provide a convenient and useful method for fabricating smart tunable photoluminescent materials.
The “blue bottle”‐redox flow battery
Authors: Quarthal Dominik , Novotny Jana , Oetken Marco
Published: March 2018

Im folgenden Beitrag soll eine Hybrid‐Redox‐Flow‐Batterie vorgestellt werden, in welcher eine wässrige Methylenblaulösung als Katholyt verwendet wird. Diese Batterie hat den Vorteil, dass die oxidierte/reduzierte Form des Elektrolyten durch einen eindrucksvollen Farbwechsel sichtbar gemacht werden kann. Der Aufbau unserer Hybrid‐Redox‐Flow‐Batterie ermöglicht es erstmals, dass das „Blue Bottle‐ Experiment“ auch durch einen elektrochemischen Oxidations‐ und Reduktionsvorgang in sehr kurzer Zeit durchgeführt werden kann.
In‐hospital outcomes comparison of transfemoral vs transapical transcatheter aortic valve replacement in propensity‐matched cohorts with severe aortic stenosis
Authors: Doshi Rajkumar , Shah Priyank , Meraj Perwaiz M.
Published: March 2018

Background

Transcatheter aortic valve replacement (TAVR) is the preferred option for high‐risk patients with severe aortic stenosis. The preferred access for TAVR is transfemoral (TF). Alternatives include the transapical (TA), trans‐subclavian (TS), and direct aortic (TAo) approaches.

Hypothesis

The TF approach is associated with lower in‐hospital outcomes as well as shorter length of stay and lower cost of hospitalization.

Methods

The National Inpatient Sample database from 2012 through 2014 was used to obtain the TAVR study population. International Classification of Diseases, 9th Revision, Clinical Modification procedure codes were utilized to identify the 2 groups. In‐hospital outcomes were compared in propensity‐score‐matched (1:3) cohorts, in which we took TA‐TAVR as a control.

Results

A total of 8210 (weighted N = 41 050) patients were identified. Of these, 1622 (weighted N = 8110) patients underwent TA‐TAVR and 6588 (weighted N = 32 940) patients underwent TF‐TAVR. In‐hospital mortality was lower with TF‐TAVR (4% vs 5.4%; P = 0.0355), along with a shorter length of stay (7.7 vs 9.7 days; P < 0.0001) and lower median hospitalization cost ($64 216 vs $74 735; P < 0.0001). Secondary outcomes of acute renal failure, transfusion, cardiogenic shock, and composite of all complications were lower with TF‐TAVR.

Conclusions

TF‐TAVR is safer and associated with lower in‐hospital outcomes compared with TA‐TAVR and should be the preferred approach. As TAVR is gaining popularity in intermediate‐ and low‐risk patients, we must not lose sight of the serious mortality and secondary outcomes associated with TA‐TAVR access.
Intermediate filament protein evolution and protists
Authors: Preisner Harald , Habicht Jörn , Garg Sriram G. , Gould Sven B.
Published: March 2018

Metazoans evolved from a single protist lineage. While all eukaryotes share a conserved actin and tubulin‐based cytoskeleton, it is commonly perceived that intermediate filaments (IFs), including lamin, vimentin or keratin among many others, are restricted to metazoans. Actin and tubulin proteins are conserved enough to be detectable across all eukaryotic genomes using standard phylogenetic methods, but IF proteins, in contrast, are notoriously difficult to identify by such means. Since the 1950s, dozens of cytoskeletal proteins in protists have been identified that seemingly do not belong to any of the IF families described for metazoans, yet, from a structural and functional perspective fit criteria that define metazoan IF proteins. Here, we briefly review IF protein discovery in metazoans and the implications this had for the definition of this protein family. We argue that the many cytoskeletal and filament‐forming proteins of protists should be incorporated into a more comprehensive picture of IF evolution by aligning it with the recent identification of lamins across the phylogenetic diversity of eukaryotic supergroups. This then brings forth the question of how the diversity of IF proteins has unfolded. The evolution of IF proteins likely represents an example of convergent evolution, which, in combination with the speed with which these cytoskeletal proteins are evolving, generated their current diversity. IF proteins did not first emerge in metazoa, but in protists. Only the emergence of cytosolic IF proteins that appear to stem from a nuclear lamin is unique to animals and coincided with the emergence of true animal multicellularity.
Spindle assembly in egg extracts of the Marsabit clawed frog, Xenopus borealis
Authors: Kitaoka Maiko , Heald Rebecca , Gibeaux Romain
Published: March 2018

Egg extracts of the African clawed frog Xenopus laevis have provided a cell‐free system instrumental in elucidating events of the cell cycle, including mechanisms of spindle assembly. Comparison with extracts from the diploid Western clawed frog, Xenopus tropicalis, which is smaller at the organism, cellular and subcellular levels, has enabled the identification of spindle size scaling factors. We set out to characterize the Marsabit clawed frog, Xenopus borealis, which is intermediate in size between the two species, but more recently diverged in evolution from X. laevis than X. tropicalis. X. borealis eggs were slightly smaller than those of X. laevis, and slightly smaller spindles were assembled in egg extracts. Interestingly, microtubule distribution across the length of the X. borealis spindles differed from both X. laevis and X. tropicalis. Extract mixing experiments revealed common scaling phenomena among Xenopus species, while characterization of spindle factors katanin, TPX2, and Ran indicate that X. borealis spindles possess both X. laevis and X. tropicalis features. Thus, X. borealis egg extract provides a third in vitro system to investigate interspecies scaling and spindle morphometric variation.
Genomic mechanisms of fatigue in survivors of colorectal cancer
Authors: Black David S. , Cole Steve W. , Christodoulou Georgia , Figueiredo Jane C.
Published: March 2018

BACKGROUND

Many cancer survivors experience fatigue as a nagging symptom lasting years after treatment. To learn of the relevant biological pathways involved in fatigue among cancer survivors, the authors tested for an association between fatigue levels and leukocyte gene expression profiles and determined the specific mediating immune cell types.

METHODS

A sample of 89 Hispanic/Latino adults aged 60.5 years, 62% of whom were male, who were diagnosed with colorectal cancer and were 2.9 years since diagnosis provided blood for transcriptome profiling and completed a validated measure of fatigue (Multidimensional Fatigue Symptom Inventory‐Short Form). The authors applied genome‐wide transcriptional profiling of leukocyte RNA to identify gene expression activity associated with fatigue, tested for the activity of specific transcription factors involved in previously established markers of inflammation and immunologic activation, and identified the specific cell types mediating these transcriptional alterations.

RESULTS

In analyses adjusting for demographic and behavioral health risk factors, results linked fatigue with increased activation of B lymphocytes and CD8‐positive T cells, as well as several transcription factors involved in immune activation (nuclear factor κB [NF‐κB], signal transducer and activator of transcription [STAT], and cAMP responsive element‐binding protein [CREB]). Results also replicated several specific genomic effects previously observed in fatigued cancer survivors, including upregulated expression of α‐synuclein (SNCA) and hemoglobin subunits (HBA and HBB).

CONCLUSIONS

Cancer survivors' heightened fatigue levels may be partially explained by activation of specific immune cell subsets, thereby providing a potential molecular biomarker for clinical interventions targeting the remediation of fatigue. Cancer 2018;124:2637‐44. © 2018 American Cancer Society.
Optimal configuration of active and backup servers for augmented reality cooperative games
Authors: Bujari Armir , De Giovanni Luigi , Palazzi Claudio E.
Published: March 2018

Interactive applications as online games and mobile devices have grown in popularity. From their combination, new and interesting cooperative services could be generated. For instance, gamers endowed with Augmented Reality (AR) visors, connected as wireless nodes in an ad‐hoc network, can interact with each other while immersed in the game. To enable this vision, we discuss here a hybrid architecture enabling game play in ad‐hoc mode instead of the traditional client‐server setting. In our architecture, one of the player nodes also acts as the server of the game, whereas other backup server nodes are ready to become active servers in case of network disconnection, ie, due to low energy level of the currently active server. This allows to have a longer gaming session before a disconnection occurs due to energy exhaustion. In this context, the server election strategy with the aim of maximizing network lifetime is not so straightforward. To this end, we have analyzed this issue through a Mixed Integer Linear Programming (MILP) model considering static network topologies and both numerical and simulation‐based analysis shows that the backup servers solution fulfills its design objective. Contemplating for mobility, we present a simulation study employing actual packet routing protocols and discuss the tradeoffs that emerge.
Electrochemical Measurement of Dopamine Release and Uptake in Zebrafish Following Treatment with Carboplatin
Authors: Field Thomas M. , Shin Mimi , Stucky Chase S. , Loomis Joseph , Johnson Michael A.
Published: March 2018

Post‐chemotherapy cognitive impairment, also known as ‘chemobrain,’ is a neurological condition in which cognitive function is impaired as a result of cancer chemotherapy treatment. In this work, we used fast‐scan cyclic voltammetry (FSCV) to measure electrically evoked dopamine release and uptake in whole brain preparations from zebrafish that have been treated with carboplatin, an agent associated with chemobrain. We administered carboplatin by addition to the fish's tank water or their food. One week of treatment with 100 μM carboplatin in the water was needed to significantly impair dopamine release (∼40 % of control); however, only one day of treatment through the zebrafish's food was needed to cause a similar impairment. Atomic absorption spectroscopy measurements suggested that administration through food resulted in higher initial levels of carboplatin compared to water administration, but water administration resulted in an increase over time. Uptake, determined by modeling stimulated release plots, was unaffected. These results are consistent with our previous findings of diminished neurotransmitter release in rats and support a role for zebrafish in chemobrain‐related studies.
Electrochemical Responsive Superhydrophilic Surfaces of Polythiophene Derivatives towards Cell Capture and Release
Authors: Hao Yuwei , Li Yingying , Zhang Feilong , Cui Haijun , Hu Jinsong , Meng Jingxin , Wang Shutao
Published: March 2018

Highly efficient cell capture and release with low background are urgently required for early diagnosis of diseases such as cancer. Herein, we report an electrochemical responsive superhydrophilic surface exhibiting specific cell capture and release with high yields and extremely low nonspecific adhesion. Through electrochemical deposition, 3‐substituted thiophene derivatives are deposited onto indium tin oxide (ITO) nanowire arrays with 4‐n‐nonylbenzeneboronic acid (BA) as dopant, fabricating the electrochemical responsive superhydrophilic surfaces. The molecular recognition between sialic acids over‐expressed on the cell membrane and doped BAs endows the electrochemical responsive surfaces with the ability to capture and release targeted cancer cells. By adjusting the substituent group of thiophene derivatives, the surface wettability can be readily regulated and further utilized for reducing nonspecific cell adhesion. Significantly, the released cells still maintain a high proliferation ability, which indicates that the applied potential does not significantly harm the cells. Therefore, these results may provide a new strategy to achieve advanced functions of biomedical materials, such as low nonspecific adhesion.
A Review on Recent Developments and Prospects for the Oxygen Reduction Reaction on Hollow Pt‐alloy Nanoparticles
Authors: Asset Tristan , Chattot Raphaël , Fontana Marie , Mercier‐Guyon Benjamin , Job Nathalie , Dubau Laetitia , Maillard Frédéric
Published: March 2018

Due to their interesting electrocatalytic properties for the oxygen reduction reaction (ORR), hollow Pt‐alloy nanoparticles (NPs) supported on high‐surface‐area carbon attract growing interest. However, the suitable synthesis methods and associated mechanisms of formation, the reasons for their enhanced specific activity for the ORR, and the nature of adequate alloying elements and carbon supports for this type of nanocatalysts remain open questions. This Review aims at shedding light on these topics with a special emphasis on hollow PtNi NPs supported onto Vulcan C (PtNi/C). We first show how hollow Pt‐alloy/C NPs can be synthesized by a mechanism involving galvanic replacement and the nanoscale Kirkendall effect. Nickel, cobalt, copper, zinc, and iron (Ni, Co, Cu, Zn, and Fe, respectively) were tested for the formation of Pt‐alloy/C hollow nanostructures. Our results indicate that metals with standard potential −0.4<E<0.4 V (vs. the normal hydrogen electrode) and propensity to spontaneously form metal borides in the presence of sodium borohydride are adequate sacrificial templates. As they lead to smaller hollow Pt‐alloy/C NPs, mesoporous carbon supports are also best suited for this type of synthesis. A comparison of the electrocatalytic activity towards the ORR or the electrooxidation of a COads monolayer, methanol or ethanol of hollow and solid Pt‐alloy/C NPs underlines the pivotal role of the structural disorder of the metal lattice, and is supported by ab initio calculations. As evidenced by accelerated stress tests simulating proton‐exchange membrane fuel cell cathode operating conditions, the beneficial effect of structural disorder is maintained on the long term, thereby bringing promises for the synthesis of highly active and robust ORR electrocatalysts.
Local Surface Modifications Investigated by Combining Scanning Electrochemical Microscopy and Surface‐Enhanced Raman Scattering
Authors: Clausmeyer Jan , Nebel Michaela , Grützke Stefanie , Kayran Yasin U. , Schuhmann Wolfgang
Published: March 2018

Scanning electrochemical microscopy (SECM) is coupled with surface‐enhanced Raman scattering (SERS) microscopy to characterize local surface modifications. SECM is utilized for the surface patterning of para‐nitrothiophenol self‐assembled monolayers (SAMs) in the direct mode of SECM with a subsequent readout of the chemical patterns by means of combined SECM‐SERS. The SECM‐SERS combination allows monitoring of local electrochemical processes and provides simultaneous complementary spectroscopic information. The reaction products upon SAM reduction, specifically p‐aminothiophenol groups, are distinguished from the pristine SAM and locally ruptured areas.
Hexaethylbenzene: A Sterically Crowded Arene and Conformationally Versatile Ligand
Authors: McGlinchey Michael J.
Published: March 2018

The syntheses, structures and dynamic behaviour of hexaethylbenzene and its transition metal and main group element complexes are reviewed. Sterically protected intermediates in the metal‐catalysed trimerisation of 3‐hexyne to form hexaethylbenzene are described, and the organic chemistry of hexaethylbenzene and of hexamethylbenzene are compared and contrasted.
Linear Optical, Quadratic and Cubic Nonlinear Optical, Electrochemical, and Theoretical Studies of “Rigid‐Rod” Bis‐Alkynyl Ruthenium Complexes
Authors: Babgi Bandar A. , Kodikara Mahesh S. , Morshedi Mahbod , Wang Huan , Quintana Cristóbal , Schwich Torsten , Moxey Graeme J. , Van Steerteghem Nick , Clays Koen , Stranger Robert , Cifuentes Marie P. , Humphrey Mark G.
Published: March 2018

The syntheses of oligo(p‐phenylene ethynylene)s (OPEs) end‐functionalized by a nitro acceptor group and with a ligated ruthenium unit at varying locations in the OPE chain, namely, trans‐[Ru{(C≡C‐1,4‐C6H4)nNO2}(C≡CR)(dppe)2] (dppe=1,2‐bis(diphenylphosphino)ethane; n=1, R=1,4‐C6H4C≡C‐1,4‐C6H4C≡CPh, 1,4‐C6H4NEt2; n=2, R=Ph, 1,4‐C6H4C≡CPh, 1,4‐C6H4C≡C‐1,4‐C6H4C≡CPh, 1,4‐C6H4NO2, 1,4‐C6H4NEt2; n=3, R=Ph, 1,4‐C6H4C≡CPh), are reported. Their electrochemical properties were assessed by cyclic voltammetry, their linear optical properties and quadratic and cubic nonlinear optical properties were assayed by UV/Vis/NIR spectroscopy, hyper‐Rayleigh scattering studies employing nanosecond pulses at 1064 nm, and broad spectral range Z‐scan studies employing femtosecond pulses, respectively, and their linear optical properties and vibrational spectroscopic behavior in the formally RuIII state was examined by UV/Vis/NIR and IR spectroelectrochemistry, respectively. The potentials of the metal‐localized oxidation processes are sensitive to alkynyl‐ligand modification, but this effect is attenuated on π‐bridge lengthening. Computational studies employing time‐dependent density functional theory were undertaken on model complexes, with a 2D scan revealing a soft potential‐energy surface for intra‐alkynyl‐ligand aryl‐ring rotation; this is consistent with the experimentally observed blueshift in optical absorption maxima. Quadratic optical nonlinearities are significant and cubic NLO coefficients for these small complexes are small. The optimum length of the alkynyl ligands and the ideal metal location in the OPE to maximize the key coefficients have been defined.
Analysis of the Factors influencing Sustainable Development in the Insurance Industry
Authors: Ho Chao‐Chung , Huang Chih , Ou Chung‐Ya
Published: March 2018

This study aims to explore and establish the dimensions of corporate social responsibility (CSR) and guidelines for the sustainable development of business in the insurance industry in Taiwan. An, investigation and analysis is conducted using the fuzzy Delphi method (FDM) and Analytic Hierarchy Process (AHP) to obtain the dimensions of CSR and the importance ranking of sustainable development of business in the insurance industry in Taiwan. The results of this study show that the dimension of ‘managerial practices’ is the most significant, followed by ‘social practices’ and ‘environmental practices’. In terms of the importance of criteria for sustainable development, the top five are ‘information disclosure’, ‘corporate strategies and commitments’, ‘climate change‘, ‘legal compliance’, and ‘environment management’. This study expects to offer reference indicators to the insurance industry in Taiwan to promote sustainable development, and facilitate insurance companies to achieve the goal of sustainable development by promoting their CSR. Copyright © 2018 John Wiley & Sons, Ltd and ERP Environment
Social Embeddedness for Sustainability in the Aviation Sector
Authors: Payán‐Sánchez Belén , Plaza‐Úbeda José Antonio , Pérez‐Valls Miguel , Carmona‐Moreno Eva
Published: March 2018

Sustainability is a complex problem affecting multiple firms, groups, and communities, and environmental solutions need to be developed in collaboration with the industry's most relevant stakeholders.Focusing on the aviation industry, we analyze the process of generating shared knowledge from an embeddedness perspective, proposing that firms are embedded in both society and markets through networks of relationships that influence their behaviour and sustainability outcomes.This paper proposes a collaborative framework that includes academic, institutional, and company levels to improve aviation using three different tools – stakeholder engagement, alliances, and open innovation. Finally, the paper includes recommendations oriented to face the more relevant environmental issues using this approach. Copyright © 2018 John Wiley & Sons, Ltd and ERP Environment
When Advertising Highlights the Binomial Identity Values of Luxury and CSR Principles: The Examples of Louis Vuitton and Hermès
Authors: Anido Freire Naïade , Loussaïef Leïla
Published: March 2018

In a controversial context, luxury houses have followed the ancestral values of artisanal production, with respect for materials, the environment, and people, thereby facilitating their current application of the principles promoted by Corporate Social Responsibility (CSR). They used to publish their CSR results in their annual reports and via their websites but can also do it implicitly through their advertisements. For the first time, the advertising creation and decoding process together with a semiotic analysis of two Louis Vuitton and Hermès advertisements bring out the semiotic wealth of the discourse of the images and the identity narratives of each label, as well as listing the implicit identity values of luxury and linking them to the various principles of CSR. Copyright © 2018 John Wiley & Sons, Ltd and ERP Environment
Does gender diversity in the audit committee influence key audit matters' readability in the audit report? UK evidence
Authors: Velte Patrick
Published: March 2018

This paper investigates the relationship between the percentage of women on audit committees (WOAC) in UK firms and auditors' disclosures on key audit matters (KAM) from 2014 to 2015. The results show that firms with a higher percentage of WOAC have higher readability of KAM disclosures as measured by the Flesch reading ease index. By modifying our dependent and independent variables, sensitivity tests (Blau index and Fog readability index) also corroborate the expectation that WOAC will lead to greater readability of KAM disclosures, with stricter monitoring activities and greater risk avoidance in the audit committee. We provide a useful contribution to recent empirical sustainable corporate governance literature for practices, researchers, and regulators.
Structure of a Coulomb cluster in the cusp magnetic trap under microgravity conditions
Authors: D'yachkov L.G. , Ramazanov T.S. , Petrov O.F. , Vasiliev M.M. , Myasnikov M.I. , Fortov V.E. , Dzhumagulova K.N. , Gabdullin M.T. , Dosbolayev M.K. , Ussenov Y.A. , Moldabekov Zh.A. , Savin S.F. , Musabayev T.A. , Zhantayev Zh.Sh. , Aimbetov A.A.
Published: March 2018

The results of the experiment on the formation of a cluster in a cusp magnetic trap under microgravity conditions and its destruction at a gradual increase of its electric potential are discussed. It is shown that if a cluster is formed by initially uncharged particles, then the auto‐adhesion forces exert an important influence on its shape, structure, and subsequent decay. The structure of the cluster is discussed, and it is shown that it is formed by filamentary fragments.
Analysis of the plasma blob formation/transport and its effects on impurity transport in the scrape‐off layer regions
Authors: Maeda T. , Tominaga K. , Yamoto S. , Hatayama A. , Hasegawa H. , Ishiguro S.
Published: March 2018

The purpose of this study was to clarify the effects of a plasma blob on the impurity transport in the scrape‐off layer (SOL) and divertor region of fusion devices. As a first step, plasma blob formation and transport were simulated by a two‐dimensional interchange turbulence model. Its effects on impurity transport were studied by the impurity equations of motion in the trace impurity limit. The results show that a blob is produced by the interchange instability and transported radially towards the wall by the E × B drift due to the polarization electric field by the charge separation between ions and electrons inside the blob due to their magnetic drifts. The polarization electric field also induces the impurity radial E × B drift and the resultant impurity radial transport at least for impurities with a small Larmor radius in comparison with the blob size. These first results provide us with a robust basis for a more systematic study (e.g., dependence of impurity mass and charge state) and for a more quantitative evaluation of the effects of the blob on the impurity transport in the SOL and divertor region.
Modelling the effects of nitrogen doping on the carbon nanofiber growth via catalytic plasma‐enhanced chemical vapour deposition process
Authors: Gupta Ravi , Sharma Suresh C.
Published: March 2018

An analytical model is developed to describe the effects of nitrogen doping on the growth of the carbon nanofibers (CNFs) and to elucidate the growth mechanism of nitrogen‐contained carbon nanofibers (N‐CNFs) on the catalyst substrate surface through the plasma‐enhanced chemical vapour deposition (PECVD) process. The analytical model accounts for the charging of CNFs, kinetics of all plasma species (electrons, ions, and neutrals) in the reactive plasma, generation of carbon species on the catalyst nanoparticle surface due to dissociation of hydrocarbons, CNF growth due to diffusion and precipitation of carbon species, and various other processes. First‐order differential equations have been solved for glow discharge plasma parameters for undoped CNFs (CNF growth in C2H2/H2 plasma) and nitrogen‐doped CNFs (N‐CNF growth in C2H2/NH3 plasma). Our investigation found that nitrogen‐doped CNFs exhibit lower tip diameters and smaller heights compared to the undoped CNFs. In addition, we have estimated that nitrogen‐doped CNFs have more enhanced field emission characteristics than the undoped CNFs. Moreover, we have also observed that N‐CNFs' growth rate increases and tip diameter decreases as the C2H2/NH3 gas ratio decreases. The theoretical results of the present investigation are consistent with the existing experimental observations.
Possible spectroscopic signature of wave collapse in edge plasmas
Authors: Hannachi I. , Meireni M. , Rosato J. , Stamm R. , Marandet Y.
Published: March 2018

In plasmas coupled to an external energy source like a beam of energetic electrons, one can observe the non‐linear coupling of Langmuir waves with ion sound and electromagnetic waves. This non‐linear interaction of waves changes the structural and radiative properties of plasmas. Coherent wave packets are trapped in regions of high intensity, and are subjected to a wave collapse cycle. We show that the electric field of the wave packets can modify the spectral lines emitted by hydrogen atoms. Our model for this field is a sequence of envelope solitons oscillating at the plasma frequency or the upper hybrid frequency. The calculations presented concern the Hα and Hβ Balmer lines of hydrogen and show the possible modifications of the line shapes if wave collapse conditions affect the edge plasma.