Protective coating of strawberries with cellulose nanofibers.

Since shelf life of perishable foods is short, a compelling challenge is to prolong the freshness of foods with a cost-effective strategy. A perishable fruit, the strawberry, is chosen as a model perishable food and an edible film coating is applied to it using carboxymethylated cellulose nanofibers (CM-CNFs) stabilized by cationic salts. A transparent and impermeable CM-CNF film is formed at the strawberry surface using a dip coating process. The formation of the film is dependent on the electrostatic interaction between anionic CM-CNF and salt cations. Physical properties of the film are characterized and the effectiveness of edible film coating on the freshness of perishable fruit is evaluated by the measurement of weight loss, CO2 release, firmness, total solid sugar and acidity. Cellulose nanofiber is a promising cost-effective material appropriate for use as an edible coating that contributes to the long-term storage and prolonged freshness of foods.

Cytotoxic Alkaloids Derived from Marine Sponges: A Comprehensive Review.

Marine sponges (porifera) have proved to be a prolific source of unique bioactive secondary metabolites, among which the alkaloids occupy a special place in terms of unprecedented structures and outstanding biological activities. Identification of active cytotoxic alkaloids extracted from marine animals, particularly sponges, is an important strive, due to lack of knowledge on traditional experiential and ethnopharmacology investigations. In this report, a comprehensive survey of demospongian bioactive alkaloids in the range 1987-2020 had been performed with a special emphasis on the potent cytotoxic activity. Different resources and databases had been investigated, including Scifinder (database for the chemical literature) CAS (Chemical Abstract Service) search, web of science, Marin Lit (marine natural products research) database. More than 230 representatives of different classes of alkaloids had been reviewed and classified, different genera belonging to the phylum porifera had been shown to be a prolific source of alkaloidal molecules, including Agelas sp., Suberea sp., Mycale sp., Haliclona sp., Epipolasis sp., Monanchora sp., Crambe sp., Reniera sp., and Xestospongia sp., among others. The sufficient production of alkaloids derived from sponges is a prosperous approach that requires more attention in future studies to consider the constraints regarding the supply of drugs, attained from marine organisms.

Shape and Temperature Expansion of Free Volume Holes in Some Cured Polybutadiene-Polyisoprene Rubber Blends.

The free volume fraction of a macromolecular structure can be assessed theoretically by using a suitable model; however, it can also be evaluated from experimental data obtained from dilatometry and positron annihilation lifetime spectra. In this second case, a regular geometry of the sub-nanometric cavities forming the free volume has to be assumed, although in fact they are irregularly shaped. The most popular approach is to guess spherical holes, which implies an isotropic growth of these last with temperature. In this work, we compared the free volume fraction, as obtained from experiments in a set of polybutadiene and polyisoprene cured rubbers and their blends, with the analogous quantity expected by using the lattice-hole model. The results allowed us to obtain insights on the approximate shape of the holes. Indeed, a cylindrical flattened geometry of the cavities produced a better agreement with the theory than the spherical shape. Furthermore, the best fit was obtained for holes that expanded preferentially in the radial direction, with a consequent decrease of the aspect ratio with temperature.

John B. Goodenough's Role in Solid State Chemistry Community: A Thrilling Scientific Tale Told by a French Chemist.

In this tribute to John B. Goodenough I will describe how John's talk on the metal-to-nonmetal transition of vanadium oxide VO2, presented at the Bordeaux Conference (September 1964) attended by inorganic chemists, metallurgists, crystallographers, thermodynamicists and physicists, provided a pioneering vision of interdisciplinary research to come. John gave a complete description of the paradigm on how the physical properties of a solid depend on its structure and bonding, by employing the chemical notions as local distortions and interatomic distances as well as the physics notions such as band width and the Hubbard on-site repulsion U. I will illustrate how inspiring John's ideas were, by discussing the research examples of my own research group in the sixties-seventies. The fundamental approach of John B. Goodenough to Solid State Chemistry, leading particularly to lithium battery applications, is at the heart of the 2019 Nobel Prize awarded to John.

Editorial for "Materials Chemistry" Sections on Molecules.

Materials chemistry has been one of the most talked-about areas of materials research over the past decades [...].

The Importance of Strain (Preorganization) in Beryllium Bonds.

In order to explore the angular strain role on the ability of Be to form strong beryllium bonds, a theoretical study of the complexes of four beryllium derivatives of orthocloso-carboranes with eight molecules (CO, N2, NCH, CNH, OH2, SH2, NH3, and PH3) acting as Lewis bases has been carried out at the G4 computational level. The results for these complexes, which contain besides Be other electron-deficient elements, such as B, have been compared with the analogous ones formed by three beryllium salts (BeCl2, CO3Be and SO4Be) with the same set of Lewis bases. The results show the presence of large and positive values of the electrostatic potential associated to the beryllium atoms in the isolated four beryllium derivatives of ortho-carboranes, evidencing an intrinsically strong acidic nature. In addition, the LUMO orbital in these systems is also associated to the beryllium atom. These features led to short intermolecular distances and large dissociation energies in the complexes of the beryllium derivatives of ortho-carboranes with the Lewis bases. Notably, as a consequence of the special framework provided by the ortho-carboranes, some of these dissociation energies are larger than the corresponding beryllium bonds in the already strongly bound SO4Be complexes, in particular for N2 and CO bases. The localized molecular orbital energy decomposition analysis (LMOEDA) shows that among the attractive terms associated with the dissociation energy, the electrostatic term is the most important one, except for the complexes with the two previously mentioned weakest bases (N2 and CO), where the polarization term dominates. Hence, these results contribute to further confirm the importance of bending on the beryllium environment leading to strong interactions through the formation of beryllium bonds.

From protocells to prototissues: a materials chemistry approach.

Prototissues comprise free-standing 3D networks of interconnected protocell consortia that communicate and display synergistic functions. Significantly, they can be constructed from functional molecules and materials, providing unprecedented opportunities to design tissue-like architectures that can do more than simply mimic living tissues. They could function under extreme conditions and exhibit a wide range of mechanical properties and bio-inspired metabolic functions. In this perspective, I will start by describing recent advancements in the design and synthetic construction of prototissues. I will then discuss the next challenges and the future impact of this emerging research field, which is destined to find applications in the most diverse areas of science and technology, from biomedical science to environmental science, and soft robotics.

Azeotropes as Powerful Tool for Waste Minimization in Industry and Chemical Processes.

Aiming for more sustainable chemical production requires an urgent shift towards synthetic approaches designed for waste minimization. In this context the use of azeotropes can be an effective tool for "recycling" and minimizing the large volumes of solvents, especially in aqueous mixtures, used. This review discusses the implementation of different kinds of azeotropic mixtures in relation to the environmental and economic benefits linked to their recovery and re-use. Examples of the use of azeotropes playing a role in the process performance and in the purification steps maximizing yields while minimizing waste. Where possible, the advantages reported have been highlighted by using E-factor calculations. Lastly azeotrope potentiality in waste valorization to afford value-added materials is given.

Interactions in Model Ionic Dyads and Triads Containing Tetrel Atoms.

The interactions in model ionic YTX3···Z (Y = NC, F, Cl, Br; X = F, Cl, Br, Z = F-, Cl-, Br-, Li+) dyads containing the tetrel atoms, T = C, Si, Ge, were studied using ab initio computational methods, including an energy decomposition analysis, which found that the YTX3 molecules were stabilized by both anions (via tetrel bonding) and cations (via polarization). For the tetrel-bonded dyads, both the electrostatic and polarization forces make comparable contributions to the binding in the C-containing dyads, whereas, electrostatic forces are by far the largest contributor to the binding in the Si- and Ge-containing analogues. Model metastable Li+···NCTCl3···F- (T = C, Si, Ge) triads were found to be lower in energy than the combined energy of the Li+ + NCTCl3 + F- fragments. The pair energies and cooperative energies for these highly polar triads were also computed and discussed.

Study on Synergistic Corrosion Inhibition Effect between Calcium Lignosulfonate (CLS) and Inorganic Inhibitors on Q235 Carbon Steel in Alkaline Environment with Cl.

The synergistic corrosion inhibition effect between calcium lignosulfonate (CLS) and three kinds of inorganic inhibitors (Na2MoO4, Na2SnO3, and NaWO4) with various molar ratios on Q235 carbon steel in alkaline solution (pH 11.5) with 0.02 mol/L NaCl was investigated by cyclic potentiodynamic polarization, electrochemical impedance spectroscopy, linear polarization, scanning electron microscopy, and X-ray photoelectron spectroscopy. Molybdate and stannate in hybrid inhibitor could promote the passivation of steel and form a complex film, which could suppress the corrosion effectively. Moreover, the insoluble metal oxides in the complex film formed by three kinds of inorganic inhibitor could help the adsorption of CLS onto the steel surface. The CLS molecules could adsorb onto the steel surface and metal oxides to form an adsorption film to protect the steel from corrosion. A three-layer protection film formed by a hybrid inhibitor, including passivation film, deposition film, and adsorption film, would effectively inhibit the corrosion reactions on the steel surface. The CLS compound with molybdate with the ratio of 2:3 shows the best inhibition effect on both general corrosion and localized corrosion.

Recent Advances in Affinity MOF-Based Sorbents with Sample Preparation Purposes.

This review summarizes the recent advances concerning metal-organic frameworks (MOFs) modified with several biomolecules (e.g., amino acids, nucleobases, proteins, antibodies, aptamers, etc.) as ligands to prepare affinity-based sorbents for application in the sample preparation field. The preparation and incorporation strategies of these MOF-based affinity materials were described. Additionally, the different types of ligands that can be employed for the synthesis of these biocomposites and their application as sorbents for the selective extraction of molecules and clean-up of complex real samples is reported. The most important features of the developed biocomposites will be discussed throughout the text in different sections, and several examples will be also commented on in detail.

Synthesis of Hierarchical Zeolites with Morphology Control: Plain and Hollow Spherical Beads of Silicalite-1 Nanosheets.

Binderless pure silica zeolites (zeosils) spheres and hollow spheres with a diameter of 20 µm composed of silicalite-1 nanosheets particles were prepared by pseudomorphic transformation of spherical silica beads using different temperatures (110, 130, and 150 °C) and treatment times (1-5 days) in order to adapt the local dissolution rate of silica to the crystallization rate of silicalite-1 nanosheets allowing to preserve the initial morphology of the silica beads. Fully crystalline beads of 20 µm were obtained at 110 °C for 5 days, whereas hollow spheres similar in size were synthesized at higher temperatures. The crystallization process seems to begin at the outer surface of the amorphous silica beads and spreads with the time in the interior of the beads leading to a dissolution of the inner amorphous part of the beads to create zeosil hollow spheres for the highest treatment temperatures (130 and 150 °C). The dissolution rate of the inner amorphous part of the beads increases by increasing the hydrothermal treatment temperature from 130 to 150 °C. The silicalite-1 beads synthesized at 110 °C for 5 days showed to be promising for rapid molecular decontamination by adsorbing n-hexane in larger amount than the silicalite-1 conventional big crystals in powder forms.

Substituent Effects on NMR Spectroscopy of 2,2-Dimethylchroman-4-one Derivatives: Experimental and Theoretical Studies.

The attribution of 1H and 13C NMR signals of a library of 5-, 6- and 7-substituted 2,2-dimethylchroman-4-one derivatives is reported. Substituent effects were interpreted in terms of the Hammett equation, showing a good correlation for carbons para- to the substituent group, not for the meta- ones. Similarly, the Lynch correlation shows the additivity of the substituent chemical shifts in the case of both H and C nuclei, again with the exception of the carbons in the meta- position. Density Functional Theory (DFT)-predicted 1H and 13C chemical shifts correspond closely with experimentally observed values, with some exceptions for C NMR data; however, the correlation is valid only for the aromatic moiety and cannot be extended to the heterocyclic ring of the chroman-4-one scaffold.

Empowering Global Chemical Biology at the Dawn of the New Decade.

On January 22-24, 2020, scientific luminaries across the far-flung corners of chemical biology gathered in Geneva, Switzerland, to deliver their latest and greatest discoveries in the field. Generously supported by the Swiss National Science Foundation (SNSF), our academic partners, and industrial and journal sponsors, this chemical biology symposium in our opinion will remain memorable for several years to come, not only because of the diversity in scientific topics delivered by our invited eminent speakers as detailed herein, but it is also one-of-a-kind conference which reflected multidimensional balance-balance in age and gender, across these speakers. Such a remarkable speaker line-up doubtless attracted >200 attendees from academia and industry in and around Switzerland and beyond, representing a huge swathe of subfields of science interfacing chemistry and biology. Poster presentations from students and postdocs further spotlighted the exciting diversity in the field: spanning biosynthesis, optochemical genetics, genetic code expansion, lipid chemical biology, redox perturbation, microfluidics screening, membrane signaling, immune modulation, DNA circuits, and synthetic and computational biology. This notable heterogeneity in scientific topics also went hand-in-hand with the diverse representations of student/postdoc trainees from 56 institutions covering 14 countries worldwide, allowing us to witness science as a truly global enterprise.

A Critical Appraisal of Dimolybdenum Tetraacetate Application in Stereochemical Studies of vic-Diols by Circular Dichroism.

This critical appraisal is intended for users of the dimolybdenum method, well-established in electronic circular dichroism (ECD) to determine the absolute configuration of vic-diols and, in particular, for experimental researchers not being experts in chiroptical methods. The main goal is to demonstrate how to avoid misleading and ambiguous conclusions resulting from the rigorous application of the helicity rule by limiting the analysis to the vic-diol unit alone. We particularly focused on multichromophoric systems, especially those that may interfere with the absorption of an in situ formed dimolybdenum tetraacetate-diol complex. In this context, examples are presented of vic-diols for which stereochemical assignment based solely on the helicity rule is ambiguous and does not necessarily lead to correct results. The motivation for choosing these examples was to demonstrate the impact of the structure of the substrate on the complexation process with the metal core and its selectivity. For each selected case, results obtained are analyzed in detail together with a discussion of existing restrictions and choice of a support method to increase the credibility of the conclusion. Based on seven both educational and challenging examples, it was shown that the dimolybdenum methodology can also be effectively applied to complex chromophoric systems, provided that other chiroptical methods and/or computational support verify obtained results.

On Supramolecular Self-Assembly: Interview with Samuel Stupp.

Ranging from 2D assemblies to peptide amphiphile-based biomaterials, Prof. Samuel Stupp and his team have enriched the scientific community with many breakthroughs in the field of supramolecular self-assembly. This Interview offers the unique possibility to share some highlights along his journey, providing also a glimpse to his vision of the future of supramolecular chemistry. Interdisciplinarity is an integral part of Prof. Stupp's research philosophy, and, using his own words, "it is the only way to understand the complex universe around us and help society along the way". What a great guideline to us all!