Hydration water and ionic aggregation in aqueous solutions of imidazolium-based protic ionic liquids

Water molecules, present as additive or as contaminant of Protic Ionic Liquids (PILs), can compete for the hydrogen bond sites leading to important modifications of the local order of these liquids and to the modulation of their physical–chemical properties. In this work, aqueous solutions of a set of N-methylimidazolium-based PILs [MIM][X] (X = NO3-- , TfO-- , HSO4-- , and Cl-- ) were investigated by deep UV Resonance Raman (UVRR) spectroscopy in the water-rich domain where ionic aggregates and bulk-like water coexist. A differential method was used to analyze the OH stretching profile to extract the so-called solute-correlated (SC) spectrum, which is particular informative of the hydration features of the PILs. Moreover, specific bands of the cation, sensitive to the hydrogen bonding, were comparatively investigated. The progressive evolution from solvent-separated ion pairs (SIP) and/or solvent-shared ion pairs (SSIP) to contact ion pairs (CIP) and/or larger ionic aggregates can be monitored as a function of the hydration level, in the water-rich domain. Our approach showed that, in the highly diluted regime, the hydration environment around the [MIM] cation does not depend on the type of anion. Moreover, [MIM][NO3] and [MIM][TfO] showed cation-water (ionic) H-bonds at the NH site stronger than the cation–anion (double-ionic) ones. The analysis of SC Raman spectra points out the formation of cation–anion Hbonds (through the CH ring groups), stronger than cation-water ones, upon PILs concentration increase, especially evident in the case of [MIM][Cl]. The H-bond strength between the anion and hydration water is found to decrease following the order: [Cl] ~ [HSO4] > [NO3] > [TfO]. Chloride ions tend to perturb a larger number of water molecules than the other anions. The number of perturbed water molecules decreases at increasing PIL concentration, showing a larger dependence for [MIM][Cl], consistently with its larger propensity to form ionic aggregates. The unique response of [MIM][Cl] to hydration found by analyzing SC-UVRR data is related to the synergy of different factors such as the anion reduced size (higher charge density), spherical symmetry, and high H-bond basicity

First case of Chlamydia trachomatis L2b proctitis in a woman

AbstractSince 2003, outbreaks of lymphogranuloma venereum (LGV) have been reported in European countries, North America, and Australia. Current LGV cases have been caused by Chlamydia trachomatis serovar L2. This sexually transmitted infection is predominantly found among men who have sex with men, specifically men who are seropositive for human immunodeficiency virus and have clinical signs of proctitis. The current outbreak has been almost exclusively attributed to a new variant, designated L2b. Although urogenital cases of LGV have been described in the heterosexual population, we report the first case of C. trachomatis L2b proctitis in a woman

High-performance versatile setup for simultaneous Brillouin-Raman micro-spectroscopy

This is the author accepted manuscript. The final version is available from American Physical Society via the DOI in this record.Brillouin and Raman scattering spectroscopy are established techniques for the nondestructive contactless and label-free readout of mechanical, chemical and structural properties of condensed matter. Brillouin-Raman investigations currently require separate measurements and a site-matched approach to obtain complementary information from a sample. Here we demonstrate a new concept of fully scanning multimodal micro-spectroscopy for simultaneous detection of Brillouin and Raman light scattering in an exceptionally wide spectral range, from fractions of GHz to hundreds of THz. It yields an unprecedented 150 dB contrast, which is especially important for the analysis of opaque or turbid media such as biomedical samples, and spatial resolution on a sub-cellular scale. We report the first applications of this new multimodal method to a range of systems, from a single cell to the fast reaction kinetics of a curing process, and the mechano-chemical mapping of highly scattering biological samples.S. Corezzi acknowledges financial support from MIUR-PRIN (Project No. 2012J8X57P). S. Caponi acknowledges support from PAT (Provincia Autonoma di Trento) (GP/PAT/2012) “Grandi Progetti 2012” Project “MaDEleNA.” P. S., A. M., M. P. acknowledge financial support from Centro Nazionale Trapianti (Project: “Studio di cellule per uso clinico umano, con particolare riferimento a modelli cellulari (liposomi) e linee cellulari in interazione con crioconservanti e con materiali biocompatibili”). L. C. and S. Caponi acknowledge financial support from Consiglio Nazionale delle Ricerche-Istituto Officina dei Materiali. F. P. acnowledges support from the UK Engineering and Physical Sciences Research Council (Grant No. EP/M028739/1 (F. P.)). The authors acknowledge Jacopo Scarponi for valuable help in setting up the hardware and software system for simultaneous Raman and BLS measurements

Water Dynamics at Protein Interfaces: Ultrafast Optical Kerr Effect Study

The behavior of water molecules surrounding a protein can have an important bearing on its structure and function. Consequently, a great deal of attention has been focused on changes in the relaxation dynamics of water when it is located at the protein surface. Here we use the ultrafast optical Kerr effect to study the H-bond structure and dynamics of aqueous solutions of proteins. Measurements are made for three proteins as a function of concentration. We find that the water dynamics in the first solvation layer of the proteins are slowed by up to a factor of 8 in comparison to those in bulk water. The most marked slowdown was observed for the most hydrophilic protein studied, bovine serum albumin, whereas the most hydrophobic protein, trypsin, had a slightly smaller effect. The terahertz Raman spectra of these protein solutions resemble those of pure water up to 5 wt % of protein, above which a new feature appears at 80 cm–1, which is assigned to a bending of the protein amide chain

Disaccharide topology induces slow down in local water dynamics

Molecular level insight into water structure and structural dynamics near proteins, lipids and nucleic acids is critical to the quantitative understanding of many biophysical processes. Un- fortunately, understanding hydration and hydration dynamics around such large molecules is challenging because of the necessity of deconvoluting the effects of topography and chemical heterogeneity. Here we study, via classical all atom simulation, water structure and structural dynamics around two biologically relevant solutes large enough to have significant chemical and topological heterogeneity but small enough to be computationally tractable: the disaccharides Kojibiose and Trehalose. We find both molecules to be strongly amphiphilic (as quantified from normalized local density fluctuations) and to induce nonuniform local slowdown in water translational and rotational motion. Detailed analysis of the rotational slowdown shows that while the rotational mechanism is similar to that previously identified in other aqueous systems by Laage, Hynes and coworkers, two novel characteristics are observed: broadening of the transition state during hydrogen bond exchange (water rotation) and a subpopulation of water for which rotation is slowed because of hindered access of the new accepting water molecule to the transition state. Both of these characteristics are expected to be generic features of water rotation around larger biomolecules and, taken together, emphasize the difficulty in transferring insight into water rotation around small molecules to much larger amphiphilic solutes.This work is part of the research program of the “Stichting voor Fundamenteel Onderzoek der Materie (FOM)” which is financially supported by the “Nederlandse organisatie voor Wetenschap- pelijk Onderzoek (NWO)”. Further financial support was provided by a Marie Curie Incoming International Fellowship (RKC). We gratefully acknowledge SARA, the Dutch center for high- performance computing, for computational time and Huib Bakker and Daan Frenkel for useful critical reviews on an earlier version of this work. We thank two anonymous reviewers for their excellent work, especially for bringing to our attention calculations done on the transition state geometry of dimers and the overstructuring of the O-O radial distribution function of SPC/E water

Functional interplay within the epitranscriptome: Reality or fiction?

RNA modifications have recently emerged as an important regulatory layer of gene expression. The most prevalent and reversible modification on messenger RNA (mRNA), N6-methyladenosine, regulates most steps of RNA metabolism and its dysregulation has been associated with numerous diseases. Other modifications such as 5-methylcytosine and N1-methyladenosine have also been detected on mRNA but their abundance is lower and still debated. Adenosine to inosine RNA editing is widespread on coding and non-coding RNA and can alter mRNA decoding as well as protect against autoimmune diseases. 2'-O-methylation of the ribose and pseudouridine are widespread on ribosomal and transfer RNA and contribute to proper RNA folding and stability. While the understanding of the individual role of RNA modifications has now reached an unprecedented stage, still little is known about their interplay in the control of gene expression. In this review we discuss the examples where such interplay has been observed and speculate that with the progress of mapping technologies more of those will rapidly accumulate

CARNET DE CLINIQUE DES RONGEURS ET DU LAPIN DE COMPAGNIE

Cette étude regroupe les connaissances actuelles sur l'élevage et la pathologie des rongeurs et des lagomorphes de compagnie : lapin, cobaye, chinchilla, octodon, hamster, gerbille, rat, souris, chien de prairie, écureuil de Corée. La consultation et l'hospitalisation sont abordées dans un premier temps. Les modalités de l'élevage, en particuliers le logement, l'alimentation, la reproduction, les normes sanguines et urinaires, et les principales affections et leurs traitements sont ensuite détaillées par espèce. Enfin, après avoir rappelé les bases de l'anesthésie et des chirurgies de convenance, les auteurs présentent quelques éléments de thérapeutique. Cette thèse se veut être un manuel pratique destiné aux étudiants mais aussi aux vétérinaires praticiens confrontés de plus en plus souvent en clientèle à ces petits mammifères de compagnie.MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

In Competition for Water: Hydrated Choline Chloride:Urea vs Choline Acetate:Urea Deep Eutectic Solvents

Unlike the archetypal deep eutectic solvent (DES) choline chloride:urea (ChCl:U), fundamental knowledge of the intermolecular network in choline acetate (ChOAc) DESs and how they change upon dilution is still missing. Here we jointly use UV resonance Raman (UVRR) and NMR spectroscopy to comparatively explore how the strength and distribution of hydrogen bonding and the solvation of the components are modified in ChOAc:U and ChCl:U with increasing hydration. Overall, Raman and NMR data indicate that ChOAc:U is continuously affected by hydration and, even at low water concentrations, undergoes a breakage of DES-DES interactions, with rapid solvation of the urea portion and full exchange of mobile protons. On the contrary, ChCl:U seems to maintain its structure as small interplays gradually occur between urea in the DES and the surrounding water molecules. The combined approach provides a multifaceted consistent description of the systems, outlining the crucial role of the anion in driving the structure and dynamics of the materials and then yielding valuable data toward the exploitation of DESs as tunable systems

The effect of the COVID-19 outbreak on the periodontal status of patients with periodontitis in supportive therapy: A retrospective study

Objective:The aim of this study was to assess the impact of lockdown due to the coronavirus COVID-19 pandemic on the periodontal status of patients with periodontitis in supportive periodontal therapy. Method and materials: A retrospective analysis of patients affected by periodontitis stage III-IV-grade A, B, and C, who had their supportive periodontal therapy to September 2020, after a period of 6 months from the planned maintenance recall (March 2020) was performed. Clinical parameters full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS), and probing depth (PD) were evaluated. Patients were assigned to three groups: A (nonsmokers); B ( 10 cigarettes/day). Statistical analysis was used to compare intra-group and inter-group differences. Results: In total, 55 subjects with the mean age of 47.7 ± 7.0 years were enrolled. The number of participants in group A and group B decreased, respectively, from 25 (45.5%) to 20 (36.4%) and from 17 (30.9%) to 13 (23.6%). The C group increased from 13 (23.6%) to 22 (40.0%). A statistically significant increase in mean FMPS was recorded in group A (from 22.5 ± 3.5 to 30.0 ± 28.3; P < .0001); group B (from 22.5 ± 12.7 to 42.5 ± 3.5; P < .0001); and group C (from 22.5 ± 25.5 to 42.5 ± 10.6; P < .0001). A statistically significant increase in mean FMBS was recorded in group A (from 15.0 ± 7.1 to 25.0 ± 21.2; P < .0001); group B (from 15.0 ± 0.0 to 37.5 ± 3.5; P < .001); and group C (from 12.5 ± 3.5 to 30.0 ± 7.1; P < .0001). A statistically significant increase in mean PD was recorded in group A (from 4.48 ± 0.5 to 5.25 ± 1.2; P < .001); in group B (from 4.71 ± 0.7 to 5.38 ± 1.31; P < .0001); and group C (from 6.00 ± 0.0 to 7.09 ± 1.1; P < .0001). Conclusions: Within the limitations of this study the results showed that the pandemic period resulted in an increase in probing depth for the patients in regular SPT, possibly due to increased tobacco consumption

Hydration properties and water structure in aqueous solutions of native and modified cyclodextrins by UV Raman and Brillouin scattering

We have studied aqueous solutions of native and chemically modified cyclodextrins (CDs) by means of UV Raman and Brillouin scattering. Analysis of the spectral profile of the OH\u2010stretching Raman signal, which is sensitive to the intermolecular organization of water, reveals a remarkable reduction of the population of ordered tetrahedral water structures inside the hydration shell of substituted CDs. As a remarkable result, this destructuring effect seems to be mainly related to the number of substituted hydroxyl groups in the CD ring rather than to the chemical nature of the substituent group. UV Brillouin scattering experiments confirm the structural picture emerging from the UV Raman study, also providing an estimate of the activation energy associated to the collective H\u2010bond restructuring mechanism in CD solutions. Overall, the results provide a coherent description of the water\u2013solute interactions in aqueous solutions of CDs