The Effect of Different Vegetable Oils on Cedar Wood Surface Energy: Theoretical and Experimental Fungal Adhesion

Despite having been used for ages to preserve wood against several effects (biological attack and moisture effects) that cause its degradation, the effect of vegetable oils on the cedar wood physicochemical properties is poorly known. Thus, in this study, the hydrophobicity, electron-acceptor (γ+), and electron-donor (γ−) properties of cedar wood before and after treatment with vegetable oils have been determined using contact angle measurement. The cedar wood has kept its hydrophobic character after treatment with the different vegetable oils. It has become more hydrophobic quantitatively with values of surface energy ranged from −25.84 to −43.45 mJ/m2 and more electron donors compared to the untreated sample. Moreover, the adhesion of four fungal strains (Penicillium commune (PDLd”), Thielavia hyalocarpa, Penicillium commune (PDLd10), and Aspergillus niger) on untreated and treated cedar wood was examined theoretically and experimentally. For untreated wood, the experimental adhesion showed a positive relationship with the results obtained by the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) approach which found that all fungal strains could adhere strongly to the cedar wood material. In contrast, this relationship was not always positive after treatment. The Environmental Scanning Electron Microscopy (ESEM) has shown that P. commune (PDLd10) and A. niger were found unable to adhere to the wood surface after treatment with sunflower and rapeseed oils. In addition, the results showed that the four fungal strains’ adhesion was decreased with olive and linseed oils treatment except that of P. commune (PDLd10) treated with linseed oil.

Intestinal microbe-dependent ω3 lipid metabolite αKetoA prevents inflammatory diseases in mice and cynomolgus macaques

Dietary ω3 fatty acids have important health benefits and exert their potent bioactivity through conversion to lipid mediators. Here, we demonstrate that microbiota play an essential role in the body’s use of dietary lipids for the control of inflammatory diseases. We found that amounts of 10-hydroxy-cis-12-cis-15-octadecadienoic acid (αHYA) and 10-oxo-cis-12-cis-15-octadecadienoic acid (αKetoA) increased in the feces and serum of specific-pathogen-free, but not germ-free, mice when they were maintained on a linseed oil diet, which is high in α-linolenic acid. Intake of αKetoA, but not αHYA, exerted anti-inflammatory properties through a peroxisome proliferator-activated receptor (PPAR)γ-dependent pathway and ameliorated hapten-induced contact hypersensitivity by inhibiting the development of inducible skin-associated lymphoid tissue through suppression of chemokine secretion from macrophages and inhibition of NF-κB activation in mice and cynomolgus macaques. Administering αKetoA also improved diabetic glucose intolerance by inhibiting adipose tissue inflammation and fibrosis through decreased macrophage infiltration in adipose tissues and altering macrophage M1/M2 polarization in mice fed a high-fat diet. These results collectively indicate that αKetoA is a novel postbiotic derived from α-linolenic acid, which controls macrophage-associated inflammatory diseases and may have potential for developing therapeutic drugs as well as probiotic food products.

Influence of Fibre Treatment and Matrix Modification on Mechanical Properties of Flax Fibre Reinforced Mortars after Freeze/Thaw Cycles

The aim of this study was to examine the influence of flax fibre protection with the linseed oil and a matrix modification with cement substitution with metakaolin (in 10wt% and 15wt%) on the mechanical properties of cement-based mortars under severe environmental conditions of freeze/thaw cycles. Cement-based mortars (with the dimension of 40x40x160 mm3) were reinforced by 10mm long discrete flax fibres (Linumusitatissimum) and exposed to 51 freeze/thaw cycles under laboratory condition. Their compressive and flexural strengths, as well as specific energy absorption capacity were measured after freeze/thaw cycles and compared to the results of mortars cured for same time in water. Under freeze/thaw cycles mortars reinforced with linseed oil-treated fibres showed the same range of degradation of the compressive and flexural strengths, however, a more pronounced degradation of energy absorption capacity compared to non-treated fibre reinforced mortars was observed. The matrix modification, by partial cement substitution with metakaolin showed optimistic results under freeze/thaw cycles. The compressive strength when cement was partially substituted with metakaolin (in both dosages) increased whereas the flexural strength was slightly lower in case of 10wt% substitution and markedly lower under higher (15wt%) cement substitution. The most relevant is that the decrease of the energy absorption capacity of the fibre reinforced mortar was completely prevented when cement was substituted with metakaolin. It is shown that the energy absorption of the non-treated fibre reinforced mortars increases by 27% when cement was substituted with metakaolin (both 10wt% and 15wt%).

Bio-Stabilised Earthen Blocks: A Critical Study on Compression Tests of Immersed Samples

Currently, much consideration is given to earthen building materials regarding their highly sustainable properties. Numerous studies have highlighted their structural ability but their water sensitivity is still limiting a potentially more spread use. To limit this sensitivity several studies have recently brought out the positive effects of bio-stabilisers such as linseed oil or xanthan gum. These recent developments allow bio-stabilized earthen materials to be resistant to immersion in water. Also, a French experimental standard (XP P 13-901) for compressed earth blocks already asks for a minimal compressive strength after a two-hour immersion that is overly severe and is difficult to satisfy without the addition of high contents of hydraulic binders. In this paper, a critical study of this compressive test after immersion is conducted on bio-stabilized (linseed oil and xanthan gum) samples of different Breton earths. Some testing adjustments are suggested and the water-diffusion in the samples is followed and linked to previously obtained capillary absorption coefficients. It is shown that the effect of immersion on the mechanical strength depends on the sample size and that an equivalence between size and immersion time can be made based on an equivalent penetration depth. Linseed oil and xanthan gum help to significantly increase the compressive strength of the earthen materials after immersion and allow to avoid the addition of hydraulic binders in earthen blocks to obtained a strong water resistance. The water diffusion in the sample during the immersion can be linked to capillary absorption behaviour, thus a water content and a compressive strength after a given time of immersion could be easily predicted.

Linseed Oil and Xanthan Gum: Promising Stabilisers for Earthen Building Materials

In the current context, the development of new bio-based and local building materials is becoming mandatory. Among them, earthen materials have a strong potential to be used as sustainable structural materials but their variability and their water sensitivity impact their mechanical properties that are difficult to guaranty. Recent developments have emphasised the ability of some bio-based additions to help to ensure these properties: linseed oil and xanthan gum are part of them. In this paper three different Breton earths, representative of a certain local variability, are studied. The impact of the selected bio-based additions on earths’ rheological behaviour is followed in order to adapt it to different forming processes. Then, the mechanical properties of different earth-addition combinations at the dry state, exposed to hygric variations and immersion are investigated for different forming processes. The findings highlight the fact that xanthan gum and linseed oil have a relevant ability to stabilise earthen blocks, that can be processed using different promising forming methods.

Erosion Behaviour of Bio-Stabilised Earthen Materials

Development of earthen building materials is one of the answers that the construction sector can provide to tackle the accelerated climate change issue. However, these materials present a wide variability, even at the local scale, and their water durability can be difficult to ensure. In order to improve their durability regarding water and avoid its prejudicial effect on earthen material’s properties, the stabilisation with bio-polymers is an increasingly studied solution. In this paper a ten-minute erosion drip test is developed and performed for various combinations of Breton earths and bio-based additions or surface treatments (linseed oil, xanthan gum, casein, alginate, vegetal varnish and tannins). The final pitting depths and eroded volumes are compared and the evolution of erosion during the test is monitored. These results are also linked to previously obtained water capillary absorption coefficients. The obtained results enable to highlight the impact of bio-based additions on erodibility of earthen materials: linseed oil and xanthan gum help to protect the earth-based samples from erosion. Other original parameters characterizing the erosion of the samples during the drip test are suggested. Limitations of this type of erosion tests are also brought out.

Characterization of Two Historical Postage Stamps Made from Cotton Fibers and Their Restoration Trials Based on the Experimental Studies

Ancient stamps are suffering from the destructive effects of different kinds of inks that were prepared from different ingredients. Two Egyptian historical postage stamps printed in blue and red printing inks were evaluated and examined for their composition using a light microscope, SEM-EDS, FTIR, and Raman spectroscopic analyses. Mechanical, chemical, and deacidification treatments were done for the two stamps. Model stamps were made from the cotton pulp in the book house to simulate historical stamp paper with an average thickness of 11 microns. The unprinted and printed paper samples with printing inks that aged and unaged were treated with 0.7% Klucel G, 0.2% TiO2 NP, or a mixture of 0.7% Klucel G + 0.2% TiO2 NP, and the color change was measured and compared with the blank samples. The two stamps are suffering from high pH, where the margin color of the stamps changed to yellow-brown with weakness of the stamp paper. By SEM examination, stamps have suffered from fibers’ weakness and dryness resulting from the self-oxidation reactions. EDS elemental composition of the red stamp showed the presence of C, O, Na, Al, Si, Mg, S, Ca, Ba, and Fe, while in the blue stamp, it was C, O, Na, Al, Si, P, S, Cl, and Ca. Raman spectrometer wavelengths turn out that the blueprinting ink of the stamp was characterized with spectra of ultramarine blue (lazurite), while hematite was characterized by the red stamp. FTIR analysis for the printing inks identified that gum Arabic sample and linseed oil were the binding and color medium, respectively. From the model trials, it was observed that the treatment of a mixture of Klucel G and TiO2 NP had the best properties for the consolidation of stamps. The two historical stamps were documented through different spectroscopic analyses, and from the restoration trials, it was observed that the mixture of 7% Klucel G + 0.2% TiO2 NP appeared to be a new and effective method for recovering the historical postage stamps.

Different Effects of Vitamin C-Based Supplements on the Advance of Linseed Oil Component Oxidation and Lipolysis during In Vitro Gastrointestinal Digestion

Although widely consumed, dietary supplements based on Vitamin C contain high doses of this compound, whose impact on lipid oxidation during digestion needs to be addressed. Therefore, the effect of seven commercial supplements and of pure l-ascorbic acid and ascorbyl palmitate on linseed oil during in vitro gastrointestinal digestion was tackled. The advance of lipid oxidation was studied through the generation of oxidation compounds, the degradation of polyunsaturated fatty acyl chains and of gamma-tocopherol, by employing Proton Nuclear Magnetic Resonance. Supplements containing exclusively l-ascorbic acid enhanced the advance of linseed oil oxidation during digestion. This was evidenced by increased formation of linolenic-derived conjugated hydroxy-dienes and alkanals and by the generation of conjugated keto-dienes and reactive alpha,beta-unsaturated aldehydes, such as 4,5-epoxy-2-alkenals; moreover, gamma-tocopherol was completely degraded. Conversely, supplements composed of mixtures of ascorbic acid/salt with citric acid and carotenes, and of ascorbyl palmitate, protected linseed oil against oxidation and reduced gamma-tocopherol degradation. The study through Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry of the volatile compounds of the digests corroborated these findings. Furthermore, a decreased lipid bioaccessibility was noticed in the presence of the highest dose of l-ascorbic acid. Both the chemical form of Vitamin C and the presence of other ingredients in dietary supplements have shown to be of great relevance regarding oxidation and hydrolysis reactions occurring during lipid digestion.