Growth of ZIF-8 MOF Films with Tunable Porosity by using Poly (1-vinylimidazole) Brushes as 3D Primers

This work reports on a novel and versatile approach to control the structure of metal–organic framework (MOFs) films by using polymeric brushes as 3D primers, suitable for triggering heterogeneous MOF nucleation. As a proof-of-concept, this work explores the use of poly(1-vinylimidazole) brushes primer obtained via surface-initiated atom transfer radical polymerization (SI-ATRP) for the synthesis of Zn-based ZIF-8 MOF films. By modifying the grafting density of the brushes, smooth porous films were obtained featuring inherently hydrophobic microporosity arising from ZIF-8 structure, and an additional constructional interparticle mesoporosity, which can be employed for differential adsorption of targeted adsorbates. It was found that the grafting density modulates the constructional porosity of the films obtained; higher grafting densities result in more compact structures, while lower grafting density generates increasingly inhomogeneous films with a higher proportion of interparticle constructional porosity.     

Local boundedness of weak solutions to the Diffusive Wave Approximation of the Shallow Water equations

In this paper we prove that weak solutions to the Diffusive Wave Approximation of the Shallow Water equations

${?}_{t}u?\mathrm{?}?({(u?z)}^{\alpha }|\mathrm{?}u{|}^{\gamma ?1}\mathrm{?}u)=f$

are locally bounded. Here, u describes the height of the water, z is a given function that represents the land elevation and f is a source term accounting for evaporation, infiltration or rainfall.     

Hydrophobic modification of nanocellulose and all-cellulose composite films using deep eutectic solvent as a reaction medium

Cellulose - In this work, deep eutectic solvent (DES) based on imidazole and triethylmethylammonium chloride was used as a reaction medium for the esterification of cellulose nanofiber (CNF) and...     

Validation of TPEN as a Zinc Chelator in Fluorescence Probing of Calcium in Cells with the Indicator Fura-2

Fura-2 is widely used as a fluorescent probe to monitor dynamic changes in cytosolic free calcium in cells, where Ca²⁺ can enter through several types of voltage-operated or ligand-gated channels. However, Fura-2 is also sensitive to other metal ions, such as zinc, which may be involved in ionic channels and receptors. There is interest, in particular, in studying the synapses between mossy fibers and CA3 pyramidal cells which contain both calcium and high quantities of free or loosely bound zinc. We have found, through fluorescence probing, that endogenous zinc inhibits mossy fiber calcium transients. However, since these results might be explained by an effect of the zinc chelator N,N,N’,N’-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) on the spectral properties of Fura-2, we have carried out a validation of the method through fluorescence excitation spectra of the complex Fura-2/calcium, and show that TPEN does not affect these spectra. This supports the idea that the observed calcium enhancement is related to a zinc inhibition of presynaptic calcium mechanisms, and confirms the use of the chelator TPEN as a general procedure for the biophysical study of Ca(II) in the presence of Zn(II) using Fura-2.     

Correlation between Luminescence and EPR Spectroscopy as Evidence of Ytterbium Pair Formation in Li6Ln(BO3)3:Yb3+ (Ln=Gd,Y) Borate Single Crystals

Synthesized powders and grown single crystals of nominal compositions Li₆Ln(BO₃)₃:Yb³⁺ (Ln=Y, Gd) were investigated by means of powder and single‐crystal X‐ray diffraction (XRD), as well as optical near‐IR spectroscopy in conjunction with electron paramagnetic resonance (EPR) spectroscopy. The appearance of two distinct zero‐phonon lines suggests the existence of two kinds of Yb³⁺ ions in the single crystals. The XRD results exclude the possibility of a phase transition occurring between room and low temperatures. EPR spectra of single crystals show the presence of both isolated ions and pairs of ytterbium ions substituted for Y³⁺. A strong temperature dependence of the intensity of Yb–Yb pairs resonance lines coincides with temperature dependence of emission peak at 978 nm, confirming a common origin of the defect giving rise to these spectra. Calculated from EPR spectra, the distance between pairs of Yb³⁺ is in good agreement with crystallographic ones: R=3.856 Å, R_cryst=3.849 Å.     

Application of Ionic Liquids in Electrochemistry—Recent Advances

In this review, the roles of room temperature ionic liquids (RTILs) and RTIL based solvent systems as proposed alternatives for conventional organic electrolyte solutions are described. Ionic liquids are introduced as well as the relevant properties for their use in electrochemistry (reduction of ohmic losses), such as diffusive molecular motion and ionic conductivity. We have restricted ourselves to provide a survey on the latest, most representative developments and progress made in the use of ionic liquids as electrolytes, in particular achieved by the cyclic voltammetry technique. Thus, the present review comprises literature from 2015 onward covering the different aspects of RTILs, from the knowledge of these media to the use of their properties for electrochemical processes. Out of the scope of this review are heat transfer applications, medical or biological applications, and multiphasic reactions.     

Selective Oxidation of Ethane to Acetic Acid Catalyzed by a C-Scorpionate Iron(II) Complex: A Homogeneous vs. Heterogeneous Comparison

The direct, one-pot oxidation of ethane to acetic acid was, for the first time, performed using a C-scorpionate complex anchored onto a magnetic core-shell support, the Fe₃O₄/TiO₂/[FeCl₂{κ³-HC(pz)₃}] composite. This catalytic system, where the magnetic catalyst is easily recovered and reused, is highly selective to the acetic acid synthesis. The performed green metrics calculations highlight the “greeness” of the new ethane oxidation procedure.     

Attracting graphs of skew products with non-contracting fiber maps

We study attracting graphs of step skew products from the topological and ergodic points of view where the usual contracting-like assumptions of the fiber dynamics are replaced by weaker merely topological conditions. In this context, we prove the existence of an attracting invariant graph and study its topological properties. We prove the existence of globally attracting measures and we show that (in some specific cases) the rate of convergence to these measures is exponential.