Ionic Liquid Crystals: Versatile Materials

Goossens, Karel,Lava, Kathleen,Bielawski, Christopher W.,Binnemans, Koen American Chemical Society 2016 Chemical reviews Vol.116 No.8

<P>This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the 'state-of-the-art' in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.</P>

Accurate Diffusion Coefficients of Organosoluble Reference Dyes in Organic Media Measured by Dual-Focus Fluorescence Correlation Spectroscopy

Goossens, Karel,Prior, Mira,Pacheco, Victor,Willbold, Dieter,Mü,llen, Klaus,Enderlein, Jö,rg,Hofkens, Johan,Gregor, Ingo American Chemical Society 2015 ACS NANO Vol.9 No.7

<P>Dual-focus fluorescence correlation spectroscopy (2fFCS) is a versatile method to determine accurate diffusion coefficients of fluorescent species in an absolute, reference-free manner. Whereas (either classical or dual-focus) FCS has been employed primarily in the life sciences and thus in aqueous environments, it is increasingly being used in materials chemistry, as well. These measurements are often performed in nonaqueous media such as organic solvents. However, the diffusion coefficients of reference dyes in organic solvents are not readily available. For this reason we determined the translational diffusion coefficients of several commercially available organosoluble fluorescent dyes by means of 2fFCS. The selected dyes and organic solvents span the visible spectrum and a broad range of refractive indices, respectively. The diffusion coefficients can be used as absolute reference values for the calibration of experimental FCS setups, allowing quantitative measurements to be performed. We show that reliable information about the hydrodynamic dimensions of the fluorescent species (including noncommercial compounds) within organic media can be extracted from the 2fFCS data.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-7/acsnano.5b02371/production/images/medium/nn-2015-02371p_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b02371'>ACS Electronic Supporting Info</A></P>

Anisotropic, Organic Ionic Plastic Crystal Mesophases from Persubstituted Imidazolium Pentacyanocyclopentadienide Salts

Goossens, Karel,Rakers, Lena,Heinrich, Benoî,t,Ahumada, Guillermo,Ichikawa, Takahiro,Donnio, Bertrand,Shin, Tae Joo,Bielawski, Christopher W.,Glorius, Frank American Chemical Society 2019 Chemistry of materials Vol.31 No.23

<P>We describe the synthesis, supramolecular organization, and thermal characteristics of an unprecedented family of symmetric 1,2,3,4,5-pentaalkylimidazolium ([(C<SUB><I>n</I></SUB>)<SUB>5</SUB>im]<SUP>+</SUP>) salts equipped with halide, nitrate, or pentacyanocyclopentadienide ([Cp(CN)<SUB>5</SUB>]<SUP>−</SUP>) counterions. Salts containing relatively small anions were obtained as low-melting solids, whereas those with [Cp(CN)<SUB>5</SUB>]<SUP>−</SUP> anions were found to be ionic liquids even below room temperature. A permethylated derivative, [(C<SUB>1</SUB>)<SUB>5</SUB>im][Cp(CN)<SUB>5</SUB>], proved to be exceptional. Upon heating, the salt self-organized into a new type of organic ionic plastic crystal (OIPC) mesophase, which was termed M<SUB>hex</SUB> and whose anisotropic structure featured hexagonally ordered, rotating anionic stacks positioned within a continuum composed of disordered cations. The structure of the mesophase resembles that of classical columnar liquid-crystalline phases, despite the absence of long, flexible chains. In the M<SUB>hex</SUB> phase, the cations surrounding the anionic columns effectively fulfill the role of “softening” structural constituents, much in the same way as flexible chains. The discovery of the novel mesophase, which displays a two-dimensional, and thus intrinsically anisotropic, lattice resulting from the rotation of entire ionic assemblies around a columnar axis, represents a new paradigm in the field of OIPCs. Relatively high ionic conductivities were measured in the M<SUB>hex</SUB> phase, particularly after doping with the corresponding sodium salt, Na[Cp(CN)<SUB>5</SUB>], demonstrating the materials’ potential for use in electrochemical applications such as sodium-ion batteries.</P> [FIG OMISSION]</BR>

Experimental Validation of On-Field Measurement Method for a Heat Pump System with Internal Heat Exchanger

Maria Goossens,Philippe Riviere,Cedric Teuillieres,Cong Toan Tran,Odile Cauret,Dominique Marchio 대한설비공학회 2016 International Journal of Air-Conditioning and Refr Vol.24 No.2

Determining the on-field heating capacity and coefficient of performance (COP) of residential air-to-air heat pumps (HPs) is problematic, given that measuring accurately the enthalpy and, specifically, the mass flow rate of air is challenging. This paper validates a promising on-field performance measurement method for HPs with an internal heat exchanger (IHX) as vapor injection system using experimental data obtained from air-to-water heat pump prototype in several operating conditions. The method is based on refrigerant fluid measurements and component energy/mass balances. Nonintrusive sensors, such as surface temperature sensors, are used to estimate pressure and refrigerant mass flow rate in different types of heat pump systems, including air-to-air. Obtained results compared with intrusively measured reference values in steady-state conditions are in good agreement, suggesting that a comprehensive performance analysis can be conducted in already-installed high efficiency residential IHX air-to-water HPs, as well as internal heat exchanger air-to-air HPs.

European Strategies to Control Antibiotic Resistance and Use

Herman Goossens 대한임상미생물학회 2014 Annals of clinical microbiology Vol.17 No.1

Europe has taken many political actions since 1999 to better control antimicrobial resistance and use, including two European Council Recommendations and actions taken by numerous European Union (EU) presidencies. These presidencies triggered many public health and research actions in the EU. Europe developed several very successful surveillance programmes on antimicrobial resistance and antimicrobial use, both currently coordinated by the European Centre for Disease Prevention and Control (ECDC). These surveillance programmes were able to identify emerging problems of antibiotic resistance and targets for quality improvement of antimicrobial use; they also conducted impact assessments of campaigns to reduce antibiotic use and increase hand hygiene. The public antibiotic awareness campaigns were very successful in reducing antibiotic use and resistance in countries like Belgium and France. The successes of these campaigns inspired ECDC to launch an annual European Antibiotic Awareness Day on November 18, 2008. The hand hygiene campaigns resulted in a dramatic decrease of MRSA infections in many EU Member States. However, ESBL- producing Gram-negative bacteria and Carbapenem- resistant Enterobacteriaceae and non-fermenters are increasing in most EU countries. Finally, the EU is investing hundreds of millions of EUROs in a Public Private Partnership (PPP), called the Innovative Medicines Initiative (IMI). An important initiative of IMI is the launch of the Combating Antibiotic Resistance NewDrugs4BadBugs programme. The goal of this new research programme is to create an innovative and collaborative PPP-based approach that will positively impact all aspects of the antimicrobial resistance issue, from the discovery of novel products to Phase 1-3 clinical trials. (Ann Clin Microbiol 2014;17:1-8)

Reviews : Hepatitis C virus-induced hepatocellular carcinoma

( Nicolas Goossens ),( Yujin Hoshida ) 대한간학회 2015 Clinical and Molecular Hepatology(대한간학회지) Vol.21 No.2

Hepatitis C virus (HCV) is a leading etiology of hepatocellular carcinoma (HCC). The interaction of HCV with its human host is complex and multilayered; stemming in part from the fact that HCV is a RNA virus with no ability to integrate in the host’s genome. Direct and indirect mechanisms of HCV-induced HCC include activation of multiple host pathways such as liver fibrogenic pathways, cellular and survival pathways, interaction with the immune and metabolic systems. Host factors also play a major role in HCV-induced HCC as evidenced by genomic studies identifying polymorphisms in immune, metabolic, and growth signaling systems associated with increased risk of HCC. Despite highly effective direct-acting antiviral agents, the morbidity and incidence of liver-related complications of HCV, including HCC, is likely to persist in the near future. Clinical markers to selectively identify HCV subjects at higher risk of developing HCC have been reported however they require further validation, especially in subjects who have experienced sustained virological response. Molecular biomarkers allowing further refinement of HCC risk are starting to be implemented in clinical platforms, allowing objective stratification of risk and leading to individualized therapy and surveillance for HCV individuals. Another role for molecular biomarker-based stratification could be enrichment of HCC chemoprevention clinical trials leading to smaller sample size, shorter trial duration, and reduced costs.(Clin Mol Hepatol 2015;21:105-114)

Structural insights into hydrogenated graphite prepared from fluorinated graphite through Birch−type reduction

Zhang, Xu,Goossens, Karel,Li, Wei,Chen, Xianjue,Chen, Xiong,Saxena, Manav,Lee, Sun Hwa,Bielawski, Christopher W.,Ruoff, Rodney S. Elsevier 2017 Carbon Vol.121 No.-

<P>Hydrogenated graphite was synthesized through a Birch-type reduction by treating fluorinated graphite ((CFx)(n), x similar to 1.1) with a solution of Li in liquid NH3 followed by the addition of H2O as the proton donor. The conversion was evaluated by Fourier transform infrared spectroscopy, Raman spectroscopy and powder X-ray diffraction. X-ray photoelectron spectroscopy and combustion elemental analysis were used to determine and quantify the chemical composition, giving an empirical formula of C1H0.60O0.06N0.01 for the product with no more than 2 at.% of fluorine atoms remaining. Thermal dehydrogenation of the hydrogenated material - as investigated by thermogravimetric analysis coupled to mass spectrometry - predominately occurs over the range of 350-600 degrees C. The product was also analyzed using scanning electron microscopy, atomic force microscopy and transmission electron microscopy, which collectively supported the formation of hydrogenated graphene sheets through a wet-chemical route. To elucidate the structure of the hydrogenated sample, the material was investigated by solid-state nuclear magnetic resonance spectroscopy. Direct pulse and cross-polarization nuclear magnetic resonance measurements, including spin counting, spectral editing and 2D heteronuclear correlation experiments, revealed the nature of the sp(3)- and sp(2)-hybridized carbon nuclei, and indicated that methine, methylene and quaternary sp(3)-carbon atoms were present in the hydrogenated material. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Configuring Hosts to Auto-detect (IPv6, IPv6-in-IPv4, or IPv4) Network Connectivity

( Ala Hamarsheh ),( Marnix Goossens ),( Rafe Alasem ) 한국인터넷정보학회 2011 KSII Transactions on Internet and Information Syst Vol.5 No.7

This document specifies a new IPv6 deployment protocol called CHANC, which stands for Configuring Hosts to Auto-detect (IPv6, IPv6-in-IPv4, or IPv4) Network Connectivity. The main part is an application level tunneling protocol that allows Internet Service Providers (ISPs) to rapidly start deploying IPv6 service to their subscribers whom connected to the Internet via IPv4-only access networks. It carries IPv6 packets over HTTP protocol to be transmitted across IPv4-only network infrastructure. The key aspects of this protocol are: offers IPv6 connectivity via IPv4-only access networks, stateless operation, economical solution, assures most firewall traversal, and requires simple installation and automatic configuration at customers`` hosts. All data packets and routing information of the IPv6 protocol will be carried over the IPv4 network infrastructure. A simple application and a pseudo network driver must be installed at the end-user``s hosts to make them able to work with this protocol. Such hosts will be able to auto-detect the ISP available connectivity in the following precedence: native IPv6, IPv6-in-IPv4, or no IPv6 connectivity. Because the protocol does not require changing or upgrading customer edges, a minimal cost in the deployment to IPv6 service should be expected. The simulation analysis showed that the performance of CHANC is pretty near to those of native IPv6, 6rd, and IPv4 protocols. Also, the performance of CHANC is much better than that of D6across4 protocol.

Elucidating the Electrochemical Activity of Electrolyte-Insoluble Polysulfide Species in Lithium-Sulfur Batteries

Klein, Michael J.,Goossens, Karel,Bielawski, Christopher W.,Manthiram, Arumugam The Electrochemical Society 2016 Journal of the Electrochemical Society Vol.163 No.9

<P>The direct synthesis of Li2S2, a proposed solid intermediate in the discharge of lithium-sulfur (Li-S) batteries, was accomplished by treating elemental lithium with sulfur in liquid ammonia at -41 degrees C. The as-synthesized product was analyzed by X-ray photoelectron spectroscopy (XPS) as well as X-ray diffraction (XRD) and determined to be a mixture of crystalline Li2S, amorphous Li2S2, and higher-order polysulfides (Li2Sx, x > 2). Monitored filtration followed by a tailored electrochemical approach was used to successfully remove the higher-order polysulfides and yielded a powder, which was determined by XPS to be comprised of similar to 9 mol% insoluble polysulfide species (mainly Li2S2) and similar to 91 mol% Li2S. This material was discharged galvanostatically in an electrochemical cell and, despite the lack of soluble polysulfide species, was shown to exhibit a discharge plateau at similar to 2.1 V vs. Li/Li+. This result confirmed the electrochemical reducibility of electrolyte-insoluble polysulfides in Li-S batteries. Moreover, it was determined that the reduction of solid polysulfides was confined to areas where the sulfur-sulfur bonds were in intimate contact with the conductive current collector. Finally, it was observed that commercially available Li2S samples contain significant quantities of polysulfide-type impurities. (C) The Author(s) 2016. Published by ECS. All rights reserved.</P>

Resonant Absorption of Surface Sausage and Surface Kink Modes under Photospheric Conditions

Yu, Dae Jung,Van Doorsselaere, Tom,Goossens, Marcel American Astronomical Society 2017 The Astrophysical journal Vol.850 No.1

<P>We study the effect of resonant absorption of surface sausage and surface kink modes under photospheric conditions where the slow surface sausage modes undergo resonant damping in the slow continuum and the surface kink modes in the slow and Alfven continua at the transitional layers. We use recently derived analytical formulas to obtain the damping rate (time). By considering linear density and linear pressure profiles for the transitional layers, we show that resonant absorption in the slow continuum could be an efficient mechanism for the wave damping of the slow surface sausage and slow surface kink modes while the damping rate of the slow surface kink mode in the Alfven continuum is weak. It is also found that the resonant damping of the fast surface kink mode is much stronger than that of the slow surface kink mode, showing a similar efficiency as under coronal conditions. It is worth noting that the slow body sausage and kink modes can also resonantly damp in the slow continuum for those linear profiles.</P>