Molecular docking and machine learning affinity prediction of compounds identified upon softwood bark extraction to the main protease of the SARS-CoV-2 virus.

Molecular docking of 234 unique compounds identified in the softwood bark (W set) is presented with a focus on their inhibition potential to the main protease of the SARS-CoV-2 virus 3CL (6WQF). The docking results are compared with the docking results of 866 COVID19-related compounds (S set). Furthermore, machine learning (ML) prediction of docking scores of the W set is presented using the S set trained TensorFlow, XGBoost, and SchNetPack ML approaches.

Accelerated and Natural Aging of Cellulose-Based Paper: Py-GC/MS Method.

Samples of papers artificially (2 to 60 days) and naturally (10, 45, and 56 years) aged were studied by the Py-GC/MS method to identify decomposition products. Possible reaction scenarios for cellulose degradation were developed. One of the degradation products is acetic acid, which can (auto)catalyze the cleavage of cellulose β(1→4)-glycosidic bonds of cellulose polymer chains.

Stability of Alum-Containing Paper under Alkaline Conditions.

The present contribution evaluates the methods of degradation and stabilization of alum-containing paper with a focus on the alkaline environment achieved by deacidification procedures. In terms of reviewed subjects, the contribution focuses on alum-rosin sized paper, which is still used as a carrier of knowledge and information; however, it also mentions cellulose itself and other brands of paper. The contribution summarizes the results on the homogeneity of the distribution of alum and rosin in the paper mass and on the paper surface.

Considerations on factors influencing the degradation of cellulose in alum-rosin sized paper.

In Europe, the use of aluminium(III) compounds, namely AlK(SO)·12HO and later on Al(SO)·18HO for hardening gelatin sizes was recorded as early as the 16th century. This review is focused on the critical assessment of published data concerning the following chemical aspects of paper degradation: direct influence of HO ions formed during hydrolysis of aluminium(III) species; influence of low-molecular organic acids formed within degradation processes; influence of pH variation on the redox potential of reactive oxygen species acting as oxidizing agent; consequences of the absorption of gaseous NO and SO present in the air for paper degradation; involvement of aluminium species in redox radical oxidation catalytic processes; possible effect of the coordination of Al(III) with small radius and high charge on oxygen atoms of cellulose carboxyl or hydroxyl groups. It is indicated how the understanding of the above mentioned effects can help slow down paper degradation.

Spruce Bark-A Source of Polyphenolic Compounds: Optimizing the Operating Conditions of Supercritical Carbon Dioxide Extraction.

The present study described the optimization of the extraction process with carbon dioxide in supercritical state for obtaining extractives, especially polyphenols from softwood bark, Norway spruce ( (L.) Karst.).

Use of Deep Eutectic Solvents in Polymer Chemistry-A Review.

This review deals with two overlapping issues, namely polymer chemistry and deep eutectic solvents (DESs). With regard to polymers, specific aspects of synthetic polymers, polymerization processes producing such polymers, and natural cellulose-based nanopolymers are evaluated. As for DESs, their compliance with green chemistry requirements, their basic properties and involvement in polymer chemistry are discussed.

Extraction of value-added components from food industry based and agro-forest biowastes by deep eutectic solvents.

The scientific community, experts in technology and marketing have been seeking cost-competitive and green solvents with good dissolving capacity for the valorisation of biomass and biowaste. Along with traditional solvents and techniques, deep eutectic solvents (DESs) and their bio-analogues, natural deep eutectic solvents (NADESs) are currently emerging as a new class of promising liquid media. In this review, a comprehensive summary of recent contribution of DESs to the processing and valorisation of various kinds of plant and animal based biomass and biowaste is provided.

Antibacterial and antifungal activity of phytosterols and methyl dehydroabietate of Norway spruce bark extracts.

The current study focuses on the analysis of in vitro biological activity of extract from bark of Norway spruce (Picea Abies), which can find potential application in food and cosmetic industry and pharmacology. Milled bark was subjected to Soxhlet extraction and supercritical fluid extraction to obtain two ethanol extracts. These extracts were further used to obtain their pre-extracts to n-hexane.

Characterization of Klason lignins by reversed-phase high-performance liquid chromatography using wide-pore octadecylsilica and stepwise gradients of dimethylformamide in water.

RP-HPLC using stepwise gradients of N,N-dimethylformamide (DMF) in a phosphate-buffered (pH 3.00) aqueous mobile phase and a wide-pore (30 nm) octadecylsilica column has been applied to the analysis of a variety of lignins--organocell lignin, dioxane lignin, Björkman lignin, and Klason lignins from both softwoods and hardwoods, respectively, in order to demonstrate the usefulness of the approach for their characterization. Tandem combination of spectrophotometric diode array detection and fluorimetric detection was used to acquire more detailed information about the chromatographic behavior of lignins.