A Brief Review of Transparent Wood: Synthetic Strategy, Functionalization, and Applications

: Severe pressure from energy consumption and serious pollution from non-renewable resources have urged human beings to develop green and energy-efficient materials. Transparent wood, consisting of original wood channel structure filled with resins, has favorable environmental friendliness and high transparency and haze, which holds huge potential in various important fields. Herein, a brief review of the current research activities centering on the development of transparent wood is provided. This review begins with an introduction to the background of transparent wood. Next, the cellular wall structure of wood and the synthetic strategy of transparent wood (including decolorization and impregnation) are summarized. Furthermore, the functionalization of transparent wood through doping nanomaterials or modifying resins is highlighted, and the relationship between the physicochemical properties and the potential uses (like optoelectronics, building materials, and furniture decoration) of transparent wood are clarified. Finally, a brief overview of the prospects and challenges for transparent wood is provided.

Hybrid Approach for Wood Modification: Characterization and Evaluation of Weathering Resistance of Coatings on Acetylated Wood

Wood, as a biological material, is sensitive to environmental conditions and microorganisms; therefore, wood products require protective measures to extend their service life in outdoor applications. Several modification processes are available for the improvement of wood properties, including commercially available solutions. Among the chemical treatments, acetylation by acetic anhydride is one of the most effective methods to induce chemical changes in the constitutive polymers at the cellular wall level. Acetylation reduces wood shrinkage-swelling, increases its durability against biotic agents, improves UV resistance and reduces surface erosion. However, even if the expected service life for external cladding of acetylated wood is estimated to be 60 years, the aesthetics change rapidly during the first years of exposure. Hybrid, or fusion, modification includes processes where the positive effect of a single treatment can be multiplied by merging with additional follow-up modifications. This report presents results of the performance tests of wood samples that, besides the modification by means of acetylation, were additionally protected with seven commercially available coatings. Natural weathering was conducted in Northern Italy for 15 months. Samples were characterized with numerous instruments by measuring samples collected from the stand every three months. Superior performance was observed on samples that merged both treatments. It is due to the combined effect of the wood acetylation and surface coating. Limited shrinkage/swelling of the bulk substrate due to chemical treatment substantially reduced stresses of the coating film. Hybrid process, compared to sole acetylation of wood, assured superior visual performance of the wood surface by preserving its original appearance.

Evolution of the Flax Cell Wall Composition During Development and After Gravitropism by Synchrotron Fluorescence Imaging

Flax lodging is an issue of great interest for producers due to its economic impact. To better understand its effects at the cell wall and stem scale, new knowledge regarding the cell wall composition dynamics during cell wall development and after a 90° tilt bending stress is reported. Deep-Ultra Violet fluorescence emission (DUV) dynamics recorded at the Synchrotron SOLEIL-DISCO beamline by multichannel autofluorescence imaging is reported for five cellular wall types of flax stems after an artificially induced gravitropic reaction. Three flax growth development stages, namely, the vegetative stage (VS), the fast growth (FG) and the mature stage (MS), were selected in normal plants, referred to as the control plants, or in gravitropic-induced response plants, referred to as 90° tilted plants. <br>

Evolution of the Flax Cell Wall Composition During Development and After Gravitropism by Synchrotron Fluorescence Imaging

Flax lodging is an issue of great interest for producers due to its economic impact. To better understand its effects at the cell wall and stem scale, new knowledge regarding the cell wall composition dynamics during cell wall development and after a 90° tilt bending stress is reported. Deep-Ultra Violet fluorescence emission (DUV) dynamics recorded at the Synchrotron SOLEIL-DISCO beamline by multichannel autofluorescence imaging is reported for five cellular wall types of flax stems after an artificially induced gravitropic reaction. Three flax growth development stages, namely, the vegetative stage (VS), the fast growth (FG) and the mature stage (MS), were selected in normal plants, referred to as the control plants, or in gravitropic-induced response plants, referred to as 90° tilted plants. <br>

Hydroplastic foaming of graphene aerogels and artificially intelligent tactile sensors

Direct foaming from solids is the most efficient method to fabricate porous materials. However, the ideal foaming fails to prepare aerogel of nanoparticles because the plasticity of their solids is denied by the overwhelming interface interactions. Here, we invent a hydroplastic foaming method to directly convert graphene oxide solids into aerogel bulks and microarrays, replacing the prevalent freezing method. The water intercalation plasticizes graphene oxide solids and enables direct foaming instead of catastrophic fragmentation. The bubble formation follows a general crystallization rule and allows nanometer-precision control of cellular wall thickness down to 8 nm. Bubble clustering generates hyperboloid structures with seamless basal connection and renders graphene aerogels with ultrarobust mechanical stability against extreme deformations. We exploit graphene aerogel to fabricate tactile microarray sensors with ultrasensitivity and ultrastability, achieving a high accuracy (80%) in artificially intelligent touch identification that outperforms human fingers (30%).

A Review on Staphylococcus sp. and its pathogens

The genus Staphylococcus is an important microorganism because of its direct and dangerous impact on the lives of other organisms, and Alexander Ogaston was the first to release this designation in 1880 to denote spherical bacteria usually associated with pus in wound infections. The members of this species are found in various environments such as dust, water, air, feces, on the skin, and the mucous membranes of warm-blooded vertebrates, on clothing, and other places. Most species of this species live as natural flora on human skin and mucous membranes, but some are opportunistic pathologies. The species of staphylococcus is characterized by having several virulence factors that increase the efficacy and pathogenicity of its species on the occurrence of infection due to its possession of tequic acid and the adhesion factor and other factors that enable it to get rid of the host defenses as an enzyme (Staphylokinase) or enable it to invade and spread as an enzyme (Hyaluronidase). Its possession of cellular wall proteins, its formation of the capsule and the exogenous polysaccharides and its production of various types of extracellular enzymes and various toxins such as intestinal toxins fixed in the heat, secretion of immune system inhibitors and their containment of antibiotic resistance genes. It shows the total resistance to the degradation of lysozyme. Staphylococcus aureus is resistant to many antimicrobial agents and thus produces treatment problems. The sex of staphylococcus includes 36 species and 80 subtypes, where more is clarified From 20 types of staphylococcus aureus.

The Antibacterial Activity of Lavender Essential Oil Alone and In Combination with Octenidine Dihydrochloride against MRSA Strains

In the post-antibiotic era the issue of bacterial resistance refers not only to antibiotics themselves but also to common antiseptics like octenidine dihydrochloride (OCT). This appears as an emerging challenge in terms of preventing staphylococcal infections, which are both potentially severe and easy to transfer horizontally. Essential oils have shown synergisms both with antibiotics and antiseptics. Therefore the aim of this study was to investigate the impact of lavender essential oil (LEO) on OCT efficiency towards methicillin-resistant S. aureus strains (MRSA). The LEO analyzed in this study increased the OCT’s susceptibility against MRSA strains. Subsequent FTIR analysis revealed cellular wall modifications in MRSA strain cultured in media supplemented with OCT or LEO/OCT. In conclusion, LEO appears to be a promising candidate for an efficient enhancer of conventional antiseptics.

Bactericidal Activity of a Cationic Peptide on Neisseria meningitidis

Background: The increasing prevalence of antibiotic resistant bacteria has raised an urgent need for substitute remedies. Antimicrobial peptides (AMPs) are considered promising candidates to address infections by multidrug-resistant bacteria through new mechanisms of action that require a careful evaluation of their performance. Objective: Identification of effective AMPs against Neisseria meningitidis, which represents a pathogen of great public health importance worldwide that is intrinsically resistant to some AMPs, such as polymyxin B. Methods: A cationic 11-residue peptide (KLKLLLLLKLK), referred to as poly-Leu, was synthesized and its antimeningococcal activity was compared to cecropin A and poly-P (KLKPPPPPKLK) through a variety of assays. Flow cytometry was used to measure propidium iodide uptake by N. meningitidis serotype B as an indicator of the effectiveness of each peptide when added to cultures at different concentrations. Results: The addition of the poly-Leu peptide led to a 90.3% uptake of the dye with an EC50 value of 7.9 µg mL-1. In contrast, uptake was <10% in cells grown in the absence of peptides or with an identical concentration of cecropin and poly-Pro peptides. Electron micrographs indicated that the integrity of the cellular wall and internal membrane was impacted in relation to peptide concentrations, which was confirmed by the detection of released alkaline phosphatase from the periplasmic space due to disruption of the external membrane. Conclusion: Poly-Leu peptide demonstrated definitive antimicrobial activity against N. meningitidis.