3D Cryo-Electron Microscopy Reveals the Structure of a 3-Fluorenylmethyloxycarbonyl Zipper Motif Ensuring the Self-Assembly of Tripeptide Nanofibers.

Short peptide-based supramolecular hydrogels appeared as highly interesting materials for applications in many fields. The optimization of their properties relies mainly on the design of a suitable hydrogelator through an empirical trial-and-error strategy based on the synthesis of various types of peptides. This approach is in part due to the lack of prior structural knowledge of the molecular architecture of the various families of nanofibers.

On the Solvation Properties of Menthol-Thymol Mixtures. A Molecular Dynamics Investigation.

Using classical molecular dynamics, we have investigated the solvation of catechol, resorcinol, hydroquinone and 1,4-benzoquinone at infinite dilution, in a series of menthol - thymol mixtures in which the molar fraction of thymol (x) has been increased by steps of 0.1, from 0 (pure menthol) to 1 (pure thymol). The evolution of the solvation shell around the solutes reveals that when x is increased, the average number of hydrogen bonds (HB) where the solute acts as HB acceptor (HBA) and the solvent as HB donor (HBD) increases, while the amount of HB, in which the solute acts as HBD and the solvent as HBA, decreases.

Self-Assembled Bis-Acridinium Tweezer Equilibria Controlled by Multi-Responsive Properties.

Protonated and methylated bis-acridinium tweezers built around a 2,6-diphenylpyridyl and an electron enriched 2,6-di(p-anisyl)pyridyl spacer have been synthesized. These tweezers can self-assemble in their corresponding homodimers and the associated thermodynamic parameters have been probed in organic solvents. The switching properties of the tweezers have been exploited in biphasic transfer experiments showing the shift of the equilibria towards the homodimers.

Circular Heterochiral Titanium-Based Self-Assembled Architectures.

Circular trinuclear helicates have been synthesized from a bis-biphenol strand (LH), titanium isopropoxide, and various diimine ligands. These self-assembled architectures constructed around three TiON nodes have a heterochiral structure ( symmetry) when 2,2'-bipyridine (A), 4,4'-dimethyl-2,2'-bipyridine (B), 4,4'-bromo-2,2'-bipyridine (C), or 4,4'-dimethyl-2,2'-bipyrimidine (D) is employed. Within these complexes, one nitrogen ligand is -positioned inside the metallo-macrocycle, whereas the other two diimine ligands point outside the helicate framework.

Synthesis, Characterization, and Properties of a Titanium(IV)-Tetrathiafulvalene-Based Complex.

To deeply investigate the interaction between a tetrathiafulvalene (TTF) unit and a Ti(IV) center, a monomeric heteroleptic octahedral Ti(IV) complex containing a diimine ligand composed of a 1,10-phenanthroline core fused with a TTF fragment (ligand ) was prepared. The stable complex formulated as Ti()(), where is a 2,2'-biphenolato derivative, was efficiently synthesized by following a one-step approach. This complex and its model species [Ti()()] were fully characterized in solution, and their solid-state structures were established by single-crystal X-ray diffraction analysis.

Rationale and protocol for a prospective cohort study of respiratory viral infections in patients admitted from emergency departments of community hospitals: Effect of respiratory Virus infection on EmeRgencY admission (EVERY) study.

Introduction: Respiratory syncytial virus (RSV) is a causative virus for the common cold worldwide and can result in hospitalisations and even death in patients with high-risk conditions and older adults. However, the relationship between RSV or other incidental respiratory infections and acute exacerbations of underlying conditions has not been well investigated. The primary objective of this study is to estimate RSV prevalence, risk factors for adverse outcomes or hospitalisation and their effect on the hospital course of patients with acute respiratory symptoms admitted from emergency departments.

A Chiral [2+3] Covalent Organic Cage Based on 1,1'-Bi-2-naphthol (BINOL) Units.

A [2+3] chiral covalent organic cage is produced through a dynamic covalent chemistry approach by mixing two readily available building units, viz. an enantiopure 3,3'-diformyl 2,2'-BINOL compound (A) with a triamino spacer (B). The two enantiomeric (R,R,R) and (S,S,S) forms of the cage C are formed nearly quantitatively thanks to the reversibility of the imine linkage.

Mechanistic Insights into Hyaluronic Acid Induced Peptide Nanofiber Organization in Supramolecular Hydrogels.

Composite hydrogels composed of low-molecular-weight peptide self-assemblies and polysaccharides are gaining great interest as new types of biomaterials. Interactions between polysaccharides and peptide self-assemblies are well reported, but a molecular picture of their impact on the resulting material is still missing. Using the phosphorylated tripeptide precursor Fmoc-FFY (Fmoc, fluorenylmethyloxycarbonyl; F, phenylalanine; Y, tyrosine; , phosphate group), we investigated how hyaluronic acid (HA) influences the enzyme-assisted self-assembly of Fmoc-FFY generated in situ in the presence of alkaline phosphatase (AP).

Going Up the Ladder: Stacking Four 4,4'-Bipyridine Moieties within a Ti(IV)-Based Tetranuclear Architecture.

Biphenol-based ligands have proven their ability to bind titanium(IV) centers and generate sophisticated self-assembled structures in which auxiliary nitrogen ligands often complete the coordination sphere of the metal and improve stability. Here, a central 4,4'-bipyridine, which acts as both a spacer and a source of monodentate nitrogen to complete the coordination sphere of the Ti(IV) complex, was incorporated within two bis-2,2'-biphenol strands, H and H. Both proligands possess structural features that are well adapted to form self-assembled structures built from titanium-oxygen-nitrogen units; however, their different degrees of torsional freedom strongly influenced the nuclearity of the complexes formed.

An Alternate [2×2] Grid Constructed Around TiO N Units.

The formation of a tetranuclear self-assembled species constructed around a TiO N motif is reported. This aggregate is generated from Ti(O Pr) , 2,2'-bipyrimidine (bpym) and a bis-biphenol strand (L H ) where two 2,2'-biphenol units are connected with a biphenyl spacer. The solid-state structure of the [Ti (L ) (bpym) ] architecture reveals the formation of an unprecedented chiral alternate [2×2] grid.

Chemistry on the Complex: Derivatization of TiO N -Based Complexes and Application to Multi-Step Synthesis.

The chemistry on octahedral TiO N -complexes is described. The Ti(IV)-based precursors are composed of two 3,3'-diphenyl-2,2'-biphenolato ligands (1) and one substituted 1,10-phenanthroline ligand (2-5). The application of imine condensation, palladium-catalyzed C-C bond formation or copper-catalysed azide-alkyne cycloaddition allowed the grafting of various new groups onto these species.

Hydrogen Bonding and Vaporization Thermodynamics in Hexafluoroisopropanol-Acetone and -Methanol Mixtures. A Joined Cluster Analysis and Molecular Dynamic Study.

Binary mixtures of hexafluoroisopropanol with either methanol or acetone are analyzed via classical molecular dynamics simulations and quantum cluster equilibrium calculations. In particular, their populations and thermodynamic properties are investigated with the binary quantum cluster equilibrium method, using our in-house code Peacemaker 2.8, upgraded with temperature-dependent parameters.

Cold-spray ionization mass spectrometry of the choline chloride-urea deep eutectic solvent (reline).

Cold-Spray Ionization mass spectrometry (CSI-MS) that can be compared to an electrospray ionization (ESI) source acting with a nebulizing gas cooled by liquid nitrogen is used for analyzing reline as Deep Eutectic Solvent (DES). The association of cholinium chloride salts with urea molecules is evidenced in negative CSI-MS through the chloride adduct formation. The structure of the supramolecular assemblies forming the reline ions that are observed on CSI mass spectra is rationalized by chemical quantum calculations.

Endoscopic ultrasound-guided luminal remodeling as a novel technique to restore gastroduodenal continuity.

Pyloric exclusion is a method of treatment for duodenal injury. Surgery is usually needed to restore digestive continuity in due time, yet a new surgical procedure can be challenging due to fibrotic adhesion development. We present here a retrospective case series of three patients with pyloric exclusion who underwent endoscopic ultrasound-guided duodenal repermeabilization using metallic stents.

A Bis-Acridinium Macrocycle as Multi-Responsive Receptor and Selective Phase-Transfer Agent of Perylene.

A bis-acridinium cyclophane incorporating switchable acridinium moieties linked by a 3,5-dipyridylanisole spacer was studied as a multi-responsive host for polycyclic aromatic hydrocarbon guests. Complexation of perylene was shown to be the most effective and was characterized in particular by a charge-transfer band as signal output. Effective catch and release of the guest was triggered by both chemical (proton/hydroxide) and redox stimuli.

Dipyrrolyldiketonato Titanium(IV) Complexes from Monomeric to Multinuclear Architectures: Synthesis, Stability, and Liquid-Crystal Properties.

Dipyrrolyldiketone ligands (H) are used with Ti(OPr) to afford monomeric titanium(IV) complexes displaying the general formula -[Ti()(OPr)]. The H ligands employed consist of two dipyrrolyldiketone compounds (H and H) and three diphenyl-substituted analogues (H-H). The behavior of these octahedral [Ti()(OPr)] species in solution was investigated by H NMR at variable temperatures.

Bent 1,10-Phenanthroline Ligands within Octahedral Complexes Constructed around a TiON Core.

The synthesis of monomeric octahedral complexes constructed around a TiON core bearing neocuproine derivatives is detailed. These architectures follow the [Ti()()] general formulas, where is the 6,6'-diphenyl-2,2'-biphenolato ligand and is a 1,10-phenanthroline derivative. Single-crystal analysis revealed that the neocuproine-based ligands within these architectures adopt a nonplanar geometry.

Breast feeding after caesarean delivery on maternal request: protocol of a systematic review and meta-analysis.

Introduction: Caesarean delivery under maternal request (CDMR) is a major factor contributing to the rising global rates of caesarean section (CS) procedure. The choice of CDMR without medical indications could provide a sense of assured safety by avoiding the experiences and complications of vaginal birth, and the risks related to an emergency CS. However, it might adversely influence women's breast feeding patterns and produce a long-lasting impact on maternal and neonatal health.

Is Charge Scaling Really Mandatory when Developing Fixed-Charge Atomistic Force Fields for Deep Eutectic Solvents?

In recent years, molecular dynamic simulations on choline chloride based deep eutectic solvents (DES) have flourished. Most of these studies point to the fact that in order to accurately reproduce dynamical properties of the latter using a fixed-charge atomistic force field (FF) one has to resort to charge scaling. In this work, we propose an alternative to charge scaling and show that the sole refinement of the Lennard-Jones parameters of the oxygen and hydrogen of the hydroxyl function in the GAFF v2.

Autonomous Growth of a Spatially Localized Supramolecular Hydrogel with Autocatalytic Ability.

Autocatalysis and self-assembly are key processes in developmental biology and are involved in the emergence of life. In the last decade both of these features were extensively investigated by chemists with the final goal to design synthetic living systems. Herein, we describe the autonomous growth of a self-assembled soft material, that is, a supramolecular hydrogel, able to sustain its own formation through an autocatalytic mechanism that is not based on any template effect and emerges from a peptide (hydrogelator) self-assembly.

First-line antihypertensive treatment for severe hypertension in pregnancy: A systematic review and network meta-analysis.

Background: Hydralazine, labetalol, and nifedipine are the recommended first-line treatments for severe hypertension in pregnancy. While all three are effective, there is a lack of sufficient evidence regarding their comparative safety and efficacy.

Objective: To determine the comparative safety and efficacy of the first-line treatment options for severe hypertension in pregnancy.

Supported Catalytically Active Supramolecular Hydrogels for Continuous Flow Chemistry.

Inspired by biology, one current goal in supramolecular chemistry is to control the emergence of new functionalities arising from the self-assembly of molecules. In particular, some peptides can self-assemble and generate exceptionally catalytically active fibrous networks able to underpin hydrogels. Unfortunately, the mechanical fragility of these materials is incompatible with process developments, relaying this exciting field to academic curiosity.