Search Results (32)

Polymer-matrix composites with ceramic fillers have various applications, one of which is the modification of the electric field. For this purpose, in this work, high-permittivity silicone composites with different polarization titanates were produced by mechanical mixing. The ceramic fillers chosen were CaCu₃Ti₄O₁₂, K_xFe_yTi_8−yO₁₆, and BaTiO₃ powders with high permittivity values and uniformly distributed in the polymer volume. Ceramic powders were studied by X-ray phase analysis and scanning electron microscopy methods. The proportion of ceramic powder was 25 wt.%. In parallel, composites were prepared with the addition of 25 wt.% glycerin. The functional properties of silicone composites were studied using the following parameters: the electrical strength and permittivity. The addition of all types of ceramic fillers, both together and without glycerin, led to a decrease in electrical strength (below 15 kV·mm⁻¹); the exception is the sample with the CCTO without glycerin (about 28 kV·mm⁻¹). The permittivity and the dielectric loss tangent of the composites increased as a result of the addition of fillers, especially noticeable in combination with glycerol in the low-frequency region. The obtained results are in good agreement with the literature data and can be used in the field of insulation in a high-permittivity layer to equalize equipotential fields. Full article

Dietary supplements are products taken orally, and they contain an ingredient intended to augment the diet. Many studies demonstrate clear alterations in microbe abundances and the production of microbiota-derived metabolites, such as short-chain fatty acids, following dietary changes. This review comprehensively explores the possible interactions among gut microbiota, lemon extracts, glycerin, and their mixture products. Lemon extracts/components are associated with a vast array of health benefits, including anti-inflammation, antioxidant, anti-atherosclerotic, and anti-diabetic effects. They are also associated with increased memory and decreased depression. Glycerin can reduce serum free fatty acids and mimic caloric restriction; its metabolites can function as a broad-spectrum antimicrobial. Additionally, glycerin has a dehydrating effect on the central nervous system and can reduce focal cerebral edema and improve performance by expanding plasma volume. However, it may also have side effects, such as hyperglycemia. Therefore, combined consumption of lemon extracts and glycerin may, in part, mitigate each other’s side effects while exerting their benefits. There is growing evidence that both lemon components and glycerin are metabolized by the gut microbiota and may modulate the intestinal microbiome composition. Therefore, gut microbiome alterations are also explored as an important mechanism in the gut–brain axis regulating various effects of these dietary supplements and their application in various noncommunicable neurological disorders. Full article

The addition of glycerin, vitamin C, and niacinamide to pig diets increased the redness of longissimus dorsi; however, it remains unclear how these supplements affect gut microbiota and metabolites. A total of 84 piglets (20.35 ± 2.14 kg) were randomly allotted to groups A (control), B (glycerin-supplemented), C (vitamin C and niacinamide-supplemented), and D (glycerin, vitamin C and niacinamide-supplemented) during a feeding experiment. Metagenomic and metabolomic technologies were used to analyze the fecal compositions of bile acids, metabolites, and microbiota. The results showed that compared to pigs in group A, pigs in group D had lower virulence factor expressions of lipopolysaccharide (p < 0.05), fatty acid resistance system (p < 0.05), and capsule (p < 0.01); higher fecal levels of ferric ion (p < 0.05), allolithocholic acid (p < 0.01), deoxycholic acid (p < 0.05), tauroursodeoxycholic acid dihydrate (p < 0.01), glycodeoxycholic acid (p < 0.05), L-proline (p < 0.01) and calcitriol (p < 0.01); and higher (p < 0.05) abundances of iron-acquiring microbiota (Methanobrevibacter, Clostridium, Clostridiaceae, Clostridium_sp_CAG_1000, Faecalibacterium_sp_CAG_74_58_120, Eubacteriales_Family_XIII_Incertae_Sedis, Alistipes_sp_CAG_435, Alistipes_sp_CAG_514 and Methanobrevibacter_sp_YE315). Supplementation with glycerin, vitamin C, and niacinamide to pigs significantly promoted the growth of iron-acquiring microbiota in feces, reduced the expression of some virulence factor genes of fecal pathogens, and increased the fecal levels of ferric ion, L-proline, and some secondary bile acids. The administration of glycerol, vitamin C, and niacinamide to pigs may serve as an effective measure for muscle redness improvement by altering the compositions of fecal microbiota and metabolites. Full article

Having a comprehensive knowledge of phase equilibrium is advantageous for industrial simulation and design of chemical processes. For further acquisition of primary data to facilitate the separation and purification of waste oil biodiesel systems, a liquid–liquid equilibrium (LLE) tank is deployed for the ternary system of waste oil biodiesel + methanol + glycerin, thereby enhancing the precision and efficiency of the process. The phase equilibrium system was constructed under the influence of atmospheric pressure at precise temperatures of 303.15 K, 313.15 K, and 323.15 K. The equilibrium components of each substance were analyzed by employing high-temperature gas chromatography, a sophisticated analytical method that enables the identification and quantification of individual components of a sample. Moreover, the ternary liquid–liquid equilibrium data were correlated by implementing the NRTL and UNIQUAC activity coefficient models. Subsequently, the binary interaction parameters of the ternary system were derived by conducting regression analysis. The experimental data demonstrated that the presence of lower methanol content in the system resulted in nearly immiscible biodiesel and glycerol phases, which ultimately facilitated the separation of biodiesel and glycerol. Conversely, with the increase in methanol content, the mutual solubility of biodiesel and glycerol was observed to increase gradually. The results showed that the calculated values of the NRTL and UNIQUAC models aligned well with the experimental values. The root-mean-square deviations of the NRTL and UNIQUAC models at 313.15 K were 2.76% and 3.56%, respectively. Full article

Bioglycerol is a major by-product of the biodiesel manufacturing process. Various chemical derivatives from bioglycerol would enhance its economic value. An antifreeze of glycerine acetate was chemically converted from an esterification reaction of bioglycerol with acetic acid. The photocatalyst TiO₂/SO₄²⁻ irradiated with ultraviolet light assisted the chemical conversion reaction. The molar ratio of acetic acid/bioglycerol was varied to obtain the optimum composition of the derived antifreeze product. Different cosolvents were considered to enhance the homogeneous extent between the antifreeze of glycerine acetate and biodiesel, and thus, the anti-freezing effect. The cosolvent/glycerine acetate, at various volumetric ratios from 0 to 0.25 vol.%, was blended into a commercial biodiesel. After 5 vol.% antifreeze of the glycerine acetate/cosolvent mixture of the biodiesel was added to the commercial biodiesel, the fuel properties of the biodiesel were analyzed. The effects of the cosolvent types and the blended volumetric ratio of cosolvent to the antifreeze of glycerine acetate on the fuel properties of the commercial biodiesel were analyzed to determine the optimum cosolvent type and volumetric composition of the cosolvent/glycerine acetate. The experimental results show that the antifreeze of glycerine acetate produced from the reaction of acetic acid/glycerol at a molar ratio equal to 8 under UV-light irradiation appeared to have the lowest freezing point. The UV-light irradiation on the TiO₂/SO₄²⁻ catalyst also caused higher triacylglycerol (TAG) and diacylglycerol (DAG) and lower monoacylglycerol (MAG) formation. In addition, the low-temperature fluidity was the most excellent when the volumetric percentage of the methanol/glycerine acetate was equal to 0.25 vol.%, at which the cold filter plugging point (CFPP) of the biodiesel was reduced from 3 °C for the neat biodiesel to −2 °C for the biodiesel blended with the mixture. In contrast, the effect of adding the antifreeze on the CFPP of the biodiesel was inferior; it was reduced from 3 °C for the neat biodiesel to 1 °C for the biodiesel when butanol cosolvent was added. The increase in the volumetric ratio of cosolvent/antifreeze increased the acid value and cetane index while it decreased the kinematic viscosity and CFPP. The heating value was observed to increase for butanol while decreasing for methanol with the increase in the volumetric ratio of cosolvent/antifreeze. In comparison to butanol, the cosolvent methanol caused a higher cetane index and acid value but a lower kinematic viscosity, heating value, and CFPP of the blended commercial biodiesel. Full article

The purity of crude glycerol, a by-product of biodiesel production, may be as low as 50%. Thus, it has relatively low economic value without previously applying adequate physical purification or chemical conversion processes. A solid-state sulfated acid photocatalyst, TiO₂/SO₄²⁻ was prepared in this study to catalyze the chemical conversion of bioglycerol with acetic acid to produce an antifreeze of glycerine acetate to improve the low-temperature fluidity of liquid fuel. The experimental results show that similar X-ray intensity structures appeared between the catalysts of TiO₂/SO₄²⁻ and SO₄²⁻. An infrared spectra analysis using a Fourier transform infrared (FTIR) spectrometer confirmed the successful sintering of SO₄²⁻ and ligating with TiO₂ for preparing TiO₂/SO₄²⁻. The effects of the photocatalyst were further excited by the irradiation of ultraviolet light. The highest weight percentage of glycerine acetate was obtained under a reaction time and reaction temperature of 10 h and 120 °C, respectively. In addition, it was observed that the glycerol conversion ratio reached 98.65% and the triacylglycerols compound amounted to 40.41 wt.% when the reacting molar ratio was 8. Moreover, the freezing point of the product mixture of glycerine acetate under the same molar ratio reached as low as −46.36 °C; the lowest among the products made using various molar ratios of acetic acid/glycerol. The UV light irradiation rendered higher triacylglycerols and diacylglycerols with lower diacylglycerol formation ratios than those without light irradiation. Full article

The effects of post-harvest spray treatments with essential oils (EOs) obtained from sage and aniseed on maintaining the quality of pears of the ‘Williams’ variety during storage was studied. Harvested pears were picked when they had reached their optimal maturity and underwent a treatment involving the application of aqueous solutions of glycerin, with varying amounts of sage essential oil (SEO) and aniseed essential oil (AEO). Weight loss during storage varied according to the treatment applied with the lowest values recorded for sage essential oil at concentrations of 300 ppm (6.24%) and 250 ppm (6.60%), respectively. Aniseed essential oil had a smaller effect on weight loss compared to sage essential oil. Fruit firmness was better maintained under the influence of the essential oil treatments, with those treated with sage essential oil standing out. The concentration of the essential oils that is used influences the antimicrobial activity of the post-harvest treatment that is applied, with higher essential oil concentrations leading to more pronounced decreases in the total number of mesophilic aerobic bacteria immediately after treatment (4.05 for SEO 200; 3.00 for SEO 300, respectively). The use of post-harvest techniques involving the application of aqueous solutions containing glycerol and essential plant oils by spraying can extend the shelf life of pear fruits. Full article

The objective of this study was to determine the influence of supplementing the diet of growing–finishing pigs with glycerin and/or a mixture of vitamin C and niacinamide on carcass traits and pork quality. Eighty-four weaned piglets with an initial average body weight of 20.35 ± 2.14 kg were assigned, at random, to four groups for a 103-day feeding experiment: control; glycerin-supplemented group; vitamin C and niacinamide-supplemented group; and glycerin, vitamin C and niacinamide-supplemented group. At the end of the experiment, three pigs/group were randomly selected and slaughtered, and samples were collected for analysis. The results indicated that supplementing crossbred pigs with glycerin, vitamin C and niacinamide simultaneously increased the redness (a*) value (p < 0.05), glycerol content (p < 0.01) and myristoleic acid content (p < 0.01) in the longissimus dorsi and tended to increase the level of flavor amino acids, linoleic acid, linolenic acid and erucic acid, as well as the percentage and density of type I myofibers in the longissimus dorsi and the semimembranosus muscle. Glycerin had an influence (p < 0.01) on the erucic acid content in the longissimus dorsi and the semimembranosus muscle, and vitamin C and niacinamide had an interaction effect (p < 0.05) on the redness (a*) value of the longissimus dorsi. Glycerin, vitamin C and niacinamide supplementation in the diet of crossbred pigs improved the color, flavor and nutritional value of pork, which contributed to an increased intent to purchase this product. Full article

This work devised a simple glycerol-assisted synthesis of a low-Cu²⁺-doped CoFe₂O₄ and the electrochemical detection of acetaminophen (AC). During the synthesis, several polyalcohols were tested, indicating the efficiency of glycerin as a cosolvent, aiding in the creation of electrode-modifier nanomaterials. A duration of standing time (eight hours) before calcination produces a decrease in the secondary phase of hematite. The synthesized material was used as an electrode material in the detection of AC. In acidic conditions (pH 2.5), the limit of detection (LOD) was 99.4 nM, while the limit of quantification (LOQ) was found to be (331 nM). The relative standard deviation (RSD), 3.31%, was computed. The enhanced electrocatalytic activity of a low-Cu²⁺-doped CoFe₂O₄-modified electrode Cu_0.13Co_0.87Fe₂O₄/GCE corresponds extremely well with its resistance R_ct, which was determined using the electrochemical impedance spectroscopy (EIS) technique and defined its electron transfer capacity. The possibility of a low-Cu²⁺-doped CoFe₂O₄ for the electrochemical sensing of AC in human urine samples was studied. The recovery rates ranging from 96.5 to 101.0% were obtained. These findings suggested that the Cu_0.13Co_0.87Fe₂O₄/GCE sensor has outstanding practicability and could be utilized to detect AC content in real complex biological samples. Full article

The shortage of fossil fuels and their rising prices, as well as the global demand for renewable energy and the reduction in greenhouse gas (GHG) emissions, result in an increased interest in the production of alternative biofuels, such as biodiesel or biomass pellets. In this study, the possibility of utilizing waste glycerol, as an addition to pine pellets intended for heating purposes, has been investigated. The usefulness of pellets containing glycerol additions has been compared in terms of applicable quality standards for wood pellets. The highest values of moisture (4.58%), ash (0.5%) and bulk density (650 kg/m³) were observed for pellets without glycerin waste. The addition of waste glycerol slightly increases the calorific value of the pellet (17.94 MJ/kg for 7.5% additive). A 10-kW domestic biomass boiler has been employed to burn the tested pellets. The consumption of analyzed fuels during boiler operation was determined. The concentration of CO, CO₂ and NO_x in exhaust gases has also been examined. It was observed that the addition of 7.5% of waste glycerol contributes to the reduction in NO_x concentrations by 30 ppm and CO₂ by 0.15%. The obtained experimental results were compared with the numerical calculations made with the use of ANSYS Chemkin-Pro. The conducted research indicates the legitimacy of utilizing waste glycerol as an additive to wood pellets. In addition, this type of addition has a positive effect on, among others, the increase in calorific value, as well as lower emissions of combustion products such as NO_x and CO₂. Full article

Reuterin can be produced from glycerol dehydration catalyzed by glycerol dehydratase (GDHt) in Lactobacillus reuteri and has broad application prospects in industry, agriculture, food, and other fields as it is active against prokaryotic and eukaryotic organisms and is resistant to proteases and lipases. However, high concentrations of glycerin inhibit reuterin production, and the mechanism behind this phenomenon is not clear. To elucidate the inhibitory mechanism of glycerol on reuterin synthesis in L. reuteri and provide reference data for constructing an L. reuteri culture system for highly effective 3-hydroxypropionaldehyde synthesis, we used transcriptome-sequencing technology to compare the morphologies and transcriptomes of L. reuteri cultured in a medium with or without 600 mM of glycerol. Our results showed that after the addition of 600 mM of glycerol to the culture medium and incubation for 10 h at 37 °C, the culture medium of L. reuteri LR301 exhibited the best bacteriostatic effect, and the morphology of L. reuteri cells had significantly changed. The addition of 600 mM of glycerol to the culture medium significantly altered the transcriptome and significantly downregulated the transcription of genes involved in glycol metabolism, such as gldA, dhaT, glpK, plsX, and plsY, but significantly upregulated the transcription of genes related to D-glucose synthesis. Full article

Glycerine (glycerol) is a polyol consisting of three carbon atoms bonded to hydroxyl groups. It is a by-product of the transesterification of triglycerides, such as animal fats, vegetable oils, or used cooking oils during the biodiesel production process. Crude glycerine is subject to purification processes resulting in distilled glycerine containing at least 99.5% glycerol. Currently, produced high-quality distilled glycerine is used in the food, pharmaceutical, and cosmetic industries. Recently, technologies for converting glycerol to other chemicals through catalytic processes have been intensively developed, e.g., production of bio-based 1,2-propanediol. In the near future, glycerol will certainly become a promising renewable raw material in many modern biorefineries for the synthesis of biofuels, chemicals, and bioenergy production. This paper presents the possibility of using ion exchange resins to remove impurities with trace amounts of sulphur and nitrogen compounds from crude and distilled glycerine, produced during the biodiesel production process from used cooking oils. It was determined that using ion exchange resins at the preliminary purification stage (before distillation) was ineffective. Using cationite resins to purify distilled glycerine produced from waste materials enables the removal of impurities in the form of sulphur and nitrogen compounds. Full article

The absence of artificial articular cartilage could cause the failure of artificial joints due to excessive material wear. There has been limited research on alternative materials for articular cartilage in joint prostheses, with few reducing the friction coefficient of artificial cartilage prostheses to the range of the natural cartilage friction coefficient (0.001–0.03). This work aimed to obtain and characterize mechanically and tribologically a new gel for potential application in articular replacement. Therefore, poly(hydroxyethyl methacrylate) (PHEMA)/glycerol synthetic gel was developed as a new type of artificial joint cartilage with a low friction coefficient, especially in calf serum. This glycerol material was developed via mixing HEMA and glycerin at a mass ratio of 1:1. The mechanical properties were studied, and it was found that the hardness of the synthetic gel was close to that of natural cartilage. The tribological performance of the synthetic gel was investigated using a reciprocating ball-on-plate rig. The ball samples were made of a cobalt-chromium-molybdenum (Co-Cr-Mo) alloy, and the plates were synthetic glycerol gel and two additional materials for comparison, which were ultra-high molecular polyethylene (UHMWPE) and 316L stainless steel. It was found that synthetic gel exhibited the lowest friction coefficient in both calf serum (0.018) and deionized water (0.039) compared to the other two conventional materials for knee prostheses. The surface roughness of the gel was found to be 4–5 μm through morphological analysis of wear. This newly proposed material provided a possible solution as a type of cartilage composite coating with hardness and tribological performance close to the nature of use in wear couples with artificial joints. Full article

Reversible shape memory polymers (SRMPs) have been identified as having great potential for biomedical applications due to their ability to switch between different shapes responding to stimuli. In this paper, a chitosan/glycerol (CS/GL) film with a reversible shape memory behavior was prepared, and the reversible shape memory effect (SME) and its mechanism were systematically investigated. The film with 40% glycerin/chitosan mass ratio demonstrated the best performance, with 95.7% shape recovery ratio to temporary shape one and 89.4% shape recovery ratio to temporary shape two. Moreover, it shows the capability to undergo four consecutive shape memory cycles. In addition, a new curvature measurement method was used to accurately calculate the shape recovery ratio. The suction and discharge of free water change the binding form of the hydrogen bonds inside the material, which makes a great reversible shape memory impact on the composite film. The incorporation of glycerol can enhance the precision and repeatability of the reversible shape memory effect and shortens the time used during this process. This paper gives a hypothetical premise to the preparation of two-way reversible shape memory polymers. Full article

Biopolymers based on the amniotic membrane compare favorably with synthetic materials in that, along with a specific 2D structure, they have biologically active properties. However, in recent years, there has been a tendency to perform decellularization of the biomaterial during the preparation of the scaffold. In this study, we studied the microstructure of 157 samples and identified individual biological components in the manufacture of a medical biopolymer from an amniotic membrane using various methods. Group 1 had 55 samples, and the amniotic membrane was impregnated with glycerol and dried over silica gel. Group 2 had 48 samples, and the decellularized amniotic membrane was impregnated with glycerol followed by lyophilization, Group 3 had 44 samples, and the decellularized amniotic membrane without pre-impregnation with glycerol was subjected to lyophilization. Decellularization was performed by treatment with a low-frequency ultrasound at a frequency of 24–40 kHz in an ultrasonic bath. A morphological study using a light microscope and a scanning electron microscope showed the preservation of the structure of the biomaterial and more complete decellularization in samples subjected to lyophilization without prior impregnation with glycerol. The study of the Raman spectroscopy lines of a biopolymer made from a lyophilized amniotic membrane without preliminary impregnation with glycerin showed significant differences in the intensity of the spectral lines of amides, glycogen, and proline. Additionally, in these samples, the spectral lines of Raman scattering the characteristic of glycerol were not visualized; therefore, only biological substances characteristic of the native amniotic membrane have been preserved. Full article