Diketonylpyridinium cations as a support of new ionic liquid crystals and ion-conductive materials: analysis of counter-ion effects

Ionic liquid crystals (ILCs) allow the combination of the high ionic conductivity of ionic liquids (ILs) with the supramolecular organization of liquid crystals (LCs). ILCs salts were obtained by the assembly of long-chained diketonylpyridinium cations of the type [HOO^(R(n)pyH)] + and BF_(4)^(-) , ReO_(4)^(-), NO_(3)^(-), CF_(3)SO_(3)^(-), CuCl_(4)^(2-) counter-ions. We have studied the thermal behavior of five series of compounds by differential scanning calorimetry (DSC) and hot stage polarized light optical microscopy (POM). All materials show thermotropic mesomorphism as well as crystalline polymorphism. X-ray diffraction of the [HOO^(R(12)pyH)][ReO_(4)] crystal reveals a layered structure with alternating polar and apolar sublayers. The mesophases also exhibit a lamellar arrangement detected by variable temperature powder X-ray diffraction. The CuCl_(4)^(2-) salts exhibit the best LC properties followed by the ReO_(4)^(-) ones due to low melting temperature and wide range of existence. The conductivity was probed for the mesophases in one species each from the ReO_(4)^(-) , and CuCl_(4)^(2-) families, and for the solid phase in one of the non-mesomorphic Cl^(-) salts. The highest ionic conductivity was found for the smectic mesophase of the ReO_(4)^(-) containing salt, whereas the solid phases of all salts were dominated by electronic contributions. The ionic conductivity may be favored by the mesophase lamellar structure

Explicit processing of verbal and spatial features during letter-location binding modulates oscillatory activity of a fronto-parietal network.

The present study investigated the binding of verbal and spatial features in immediate memory. In a recent study, we demonstrated incidental and asymmetrical letter-location binding effects when participants attended to letter features (but not when they attended to location features) that were associated with greater oscillatory activity over prefrontal and posterior regions during the retention period. We were interested to investigate whether the patterns of brain activity associated with the incidental binding of letters and locations observed when only the verbal feature is attended differ from those reflecting the binding resulting from the controlled/explicit processing of both verbal and spatial features. To achieve this, neural activity was recorded using magnetoencephalography (MEG) while participants performed two working memory tasks. Both tasks were identical in terms of their perceptual characteristics and only differed with respect to the task instructions. One of the tasks required participants to process both letters and locations. In the other, participants were instructed to memorize only the letters, regardless of their location. Time–frequency representation of MEG data based on the wavelet transform of the signals was calculated on a single trial basis during the maintenance period of both tasks. Critically, despite equivalent behavioural binding effects in both tasks, single and dual feature encoding relied on different neuroanatomical and neural oscillatory correlates. We propose that enhanced activation of an anterior–posterior dorsal network observed in the task requiring the processing of both features reflects the necessity for allocating greater resources to intentionally process verbal and spatial features in this task

New pyrazolium salts as a support for Ionic liquid crystals and Ionic conductors

Ionic liquid crystals (ILCs) are a class of materials that combine the properties of liquid crystals (LCs) and ionic liquids (ILs). This type of materials is directed towards properties such as conductivity in ordered systems at different temperatures. In this work, we synthesize five new families of ILCs containing symmetrical and unsymmetrical substituted pyrazolium cations, with different alkyl long-chains, and anions such as Cl‾, BF₄‾, ReO₄‾, p-CH₃₋₆H₄SO₃‾(PTS) and CF₃SO₃‾ (OTf). We study their thermal behavior by polarized light optical microscopy (POM) and differential scanning calorimetry (DSC). All of them, except those with OTf as counteranion, show thermotropic mesomorphism. The observations by POM reveal textures of lamellar mesophases. Those agree with the arrangement observed in the X-ray crystal structure of [H₂pzᴿ⁽⁴⁾‚ᴿ⁽⁴⁾][ReO₄]. The nature of the mesophases is also confirmed by variable temperature powder X-ray diffraction. On the other hand, the study of the dielectric properties at variable temperature in mesomorphic (Cl‾‾and BF₄‾) and non-mesomorphic OTf) salts indicates that the supramolecular arrangement of the mesophase favors a greater ionic mobility and therefore ionic conductivity

Lamellar columnar liquid-crystalline mesophases as a 2D platform for anhydrous proton conduction

Several series of dihalide Pd(II) compounds bearing pyridyl or isoquinolinylpyrazole ligands have been strategically designed and synthesised to exhibit columnar mesomorphism in wide stability ranges. The coordination of the pyrazoles to the fragments PdX_2 (X = Cl, Br, I) generates half-disc molecules that are capable of self-assembling into discotic dimers via intermolecular interactions. This disc-like shape is required for the supramolecular organisation of the lamellar columnar mesophases, which are formed at temperatures below 100 ºC in most cases. It was found that these metallomesogens behave as 2D proton conducting materials under anhydrous conditions. The high fluidity properties of the mesophase facilitate proton conduction as a result of the spontaneous dissociation of the acidic pyrazole proton at the melting temperature. For the first time, lamellar columnar mesophases are demonstrated to serve as a 2D platform to induce water-free proton conductivity in dihalide Pd(ii) metallomesogens

Oscillatory activity in prefrontal and posterior regions during implicit letter-location binding.

Many cognitive abilities involve the integration of information from different modalities, a process referred to as “binding.” It remains less clear, however, whether the creation of bound representations occurs in an involuntary manner, and whether the links between the constituent features of an object are symmetrical. We used magnetoencephalography to investigate whether oscillatory brain activity related to binding processes would be observed in conditions in which participants maintain one feature only (involuntary binding); and whether this activity varies as a function of the feature attended to by participants (binding asymmetry). Participants performed two probe recognition tasks that were identical in terms of their perceptual characteristics and only differed with respect to the instructions given (to memorize either consonants or locations). MEG data were reconstructed using a current source distribution estimation in the classical frequency bands. We observed implicit verbal–spatial binding only when participants successfully maintained the identity of consonants, which was associated with a selective increase in oscillatory activity over prefrontal regions in all frequency bands during the first half of the retention period and accompanied by increased activity in posterior brain regions. The increase in oscillatory activity in prefrontal areas was only observed during the verbal task, which suggests that this activity might be signaling neural processes specifically involved in cross-code binding. Current results are in agreement with proposals suggesting that the prefrontal cortex function as a “pointer” which indexes the features that belong together within an object

The CARBA-MAP study: national mapping of carbapenemases in Spain (2014–2018)

Introduction:Infections caused by carbapenem-resistant Enterobacterales (CRE) and carbapenem-resistant Pseudomonas aeruginosa, including isolates producing acquired carbapenemases, constitute a prevalent health problem worldwide. The primary objective of this study was to determine the distribution of the different carbapenemases among carbapenemase-producing Enterobacterales (CPE, specifically Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae complex, and Klebsiella aerogenes) and carbapenemase-producing P. aeruginosa (CPPA) in Spain from January 2014 to December 2018.Methods: A national, retrospective, cross-sectional multicenter study was performed. The study included the first isolate per patient and year obtained from clinical samples and obtained for diagnosis of infection in hospitalized patients. A structured questionnaire was completed by the participating centers using the REDCap platform, and results were analyzed using IBM SPSS Statistics 29.0.0.Results: A total of 2,704 carbapenemase-producing microorganisms were included, for which the type of carbapenemase was determined in 2692 cases: 2280 CPE (84.7%) and 412 CPPA (15.3%), most often using molecular methods and immunochromatographic assays. Globally, the most frequent types of carbapenemase in Enterobacterales and P. aeruginosa were OXA-48-like, alone or in combination with other enzymes (1,523 cases, 66.8%) and VIM (365 cases, 88.6%), respectively. Among Enterobacterales, carbapenemase-producing K. pneumoniae was reported in 1821 cases (79.9%), followed by E. cloacae complex in 334 cases (14.6%). In Enterobacterales, KPC is mainly present in the South and South-East regions of Spain and OXA-48-like in the rest of the country. Regarding P. aeruginosa, VIM is widely distributed all over the country. Globally, an increasing percentage of OXA-48-like enzymes was observed from 2014 to 2017. KPC enzymes were more frequent in 2017–2018 compared to 2014–2016.Discussion: Data from this study help to understand the situation and evolution of the main species of CPE and CPPA in Spain, with practical implications for control and optimal treatment of infections caused by these multi-drug resistant organisms

Dendritic polyglycerol cyclodextrin amphiphiles and their self-assembled architectures to transport hydrophobic guest molecules

Here we report for the first time a microwave assisted synthesis of polyglycerol dendron functionalized cyclodextrins (CD) with hydrophobic tails. These amphiphilic CDs consist of seven polyglycerol dendrons and fourteen alkyl chains on the primary and secondary rims of the cyclodextrin core, respectively. They self-assemble to form nanostructures in aqueous solutions and efficiently encapsulate hydrophobic aromatic guests. The size and shape of the self-assemblies and also their ability to encapsulate guest molecules depend on the generation of conjugated polyglycerol dendrons

Nanocompartmentalization of soft materials with three mutually immiscible solvents: synthesis and self-assembly of three-arm star-polyphiles

We report synthesis, thermotropic, and lyotropic mesomorphism of a family of novel “star-polyphiles”: small star-shaped molecules bearing three mutually immiscible arms, hydrophilic (oligoethylene glycol), oleophilic (alkanes), and fluorophilic (perfluorinated alkanes), attached to a central 1,3,5-trihydroxybenzene core. A facile, flexible multistep synthesis giving high-purity yields of 14 distinct members of the family is described, with variable arm lengths, forming crystalline, or various mesostructured gel phases in their neat state at room temperature. Furthermore, we show that specific members of these star-polyphiles can be simultaneously loaded with up to three mutually immiscible solvents, dodecane, perfluoro-nonane, and water, to form liquid crystals and microemulsions with multiple chemically distinct mesoscale compartments. The mesoscale chemical polyfunctionality of these polyphiles, coupled with thermotropic and lyotropic polymorphism, make them promising potential soft materials for a variety of applications, including host matrices for multiple mutually immiscible chemicals and drug deliveryWe acknowledge support from the Australian Research Council’s Discovery grant scheme