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Polymers Apr 2022In this study, hydromagnesite, a rare natural hydrated alkaline magnesium carbonate, was used to synthesize magnesium hydroxide (MH) as a flame retardant for...
In this study, hydromagnesite, a rare natural hydrated alkaline magnesium carbonate, was used to synthesize magnesium hydroxide (MH) as a flame retardant for ethylene-vinyl acetate (EVA) to enhance its fire resistance and smoke suppression. Various concentrations of sodium hydroxide (NaOH) were used to alter the morphology and the flame-retardant efficiency of synthesized MH. EVA/MH composites were prepared through melt blending, and the influence of NaOH on the flame retardancy and mechanical properties was investigated by means of the limiting oxygen index (LOI), cone calorimeter test (CCT) and tensile test. The flame retardancy results demonstrated that composites exhibited remarkably improved flame retardant properties after introducing MH, reflected by an increase in the LOI value from 20% for neat EVA to roughly 38%. Additionally, the peak of heat release rate (pHRR), the total heat release (THR) and the peak of the smoke production rate for EVA3 were decreased by 37.6%, 20.7% and 44.4% compared with neat EVA, respectively. In the meantime, increasing char residues were also observed. The incorporation of different MH concentrations had a limited effect on the mechanical properties of the EVA/MH composites.
PubMed: 35458317
DOI: 10.3390/polym14081567 -
Tissue Engineering and Regenerative... Jun 2022Autologous fat grafting is one of the most common procedures used in plastic surgery to correct soft tissue deficiency or depression deformity. However, its clinical...
BACKGROUND
Autologous fat grafting is one of the most common procedures used in plastic surgery to correct soft tissue deficiency or depression deformity. However, its clinical outcomes are often suboptimal, and lack of metabolic and architectural support at recipient sites affect fat survival leading to complications such as cyst formation, calcification. Extracellular matrix-based scaffolds, such as allograft adipose matrix (AAM) and poly(lactic-co-glycolic) acid (PLGA), have shown exceptional clinical promise as regenerative scaffolds. Magnesium hydroxide (MH), an alkaline ceramic, has attracted attention as a potential additive to improve biocompatibility. We attempted to combine fat graft with regenerative scaffolds and analyzed the changes and viability of injected fat graft in relation to the effects of injectable natural, and synthetic (PLGA/MH microsphere) biomaterials.
METHODS
In vitro cell cytotoxicity, angiogenesis of the scaffolds, and wound healing were evaluated using human dermal fibroblast cells. Subcutaneous soft-tissue integration of harvested fat tissue was investigated in vivo in nude mouse with random fat transfer protocol Fat integrity and angiogenesis were identified by qRT-PCR and immunohistochemistry.
RESULTS
In vitro cell cytotoxicity was not observed both in AAM and PLGA/MH with human dermal fibroblast. PLGA/MH and AAM showed excellent wound healing effect. In vivo, the AAM and PLGA/MH retained volume compared to that in the only fat group. And the PLGA/MH showed the highest angiogenesis and anti-inflammation.
CONCLUSION
In this study, a comparison of the volume retention effect and angiogenic ability between autologous fat grafting, injectable natural, and synthetic biomaterials will provide a reasonable basis for fat grafting.
Topics: Adipose Tissue; Allografts; Animals; Biocompatible Materials; Magnesium Hydroxide; Mice; Microspheres; Tissue Scaffolds
PubMed: 35312988
DOI: 10.1007/s13770-021-00426-0 -
Crystal Growth & Design Jul 2023Magnesium is a critical raw material and its recovery as Mg(OH) from saltwork brines can be realized via precipitation. The effective design, optimization, and scale-up...
Magnesium is a critical raw material and its recovery as Mg(OH) from saltwork brines can be realized via precipitation. The effective design, optimization, and scale-up of such a process require the development of a computational model accounting for the effect of fluid dynamics, homogeneous and heterogeneous nucleation, molecular growth, and aggregation. The unknown kinetics parameters are inferred and validated in this work by using experimental data produced with a T-mixer and a T-mixer, guaranteeing fast and efficient mixing. The flow field in the T-mixers is fully characterized by using the - turbulence model implemented in the computational fluid dynamics (CFD) code OpenFOAM. The model is based on a simplified plug flow reactor model, instructed by detailed CFD simulations. It incorporates Bromley's activity coefficient correction and a micro-mixing model for the calculation of the supersaturation ratio. The population balance equation is solved by exploiting the quadrature method of moments, and mass balances are used for updating the reactive ions concentrations, accounting for the precipitated solid. To avoid unphysical results, global constrained optimization is used for kinetics parameters identification, exploiting experimentally measured particle size distribution (PSD). The inferred kinetics set is validated by comparing PSDs at different operative conditions both in the T-mixer and the T-mixer. The developed computational model, including the kinetics parameters estimated for the first time in this work, will be used for the design of a prototype for the industrial precipitation of Mg(OH) from saltwork brines in an industrial environment.
PubMed: 37426548
DOI: 10.1021/acs.cgd.2c01179 -
FEBS Letters Sep 2020Life as we know it would not exist without water. However, water molecules not only serve as a solvent and reactant but can also promote hydrolysis, which counteracts... (Review)
Review
Life as we know it would not exist without water. However, water molecules not only serve as a solvent and reactant but can also promote hydrolysis, which counteracts the formation of essential organic molecules. This conundrum constitutes one of the central issues in origin of life. Hydrolysis is an important part of energy metabolism for all living organisms but only because, inside cells, it is a controlled reaction. How could hydrolysis have been regulated under prebiotic settings? Lower water activities possibly provide an answer: geochemical sites with less free and more bound water can supply the necessary conditions for protometabolic reactions. Such conditions occur in serpentinising systems, hydrothermal sites that synthesise hydrogen gas via rock-water interactions. Here, we summarise the parallels between biotic and abiotic means of controlling hydrolysis in order to narrow the gap between biochemical and geochemical reactions and briefly outline how hydrolysis could even have played a constructive role at the origin of molecular self-organisation.
Topics: Catalysis; Ferrosoferric Oxide; Geologic Sediments; Hydrogen; Hydrolysis; Hydrothermal Vents; Magnesium Hydroxide; Models, Chemical; Origin of Life; Seawater; Silicon Compounds; Water
PubMed: 32416624
DOI: 10.1002/1873-3468.13815 -
Biomaterials Research Dec 2022Coronary artery disease is a cardiovascular disease with a high mortality and mortality rate in modern society. Vascular stent insertion to restore blood flow is...
BACKGROUND
Coronary artery disease is a cardiovascular disease with a high mortality and mortality rate in modern society. Vascular stent insertion to restore blood flow is essential to treat this disease. A fully biodegradable vascular scaffold (BVS) is a vascular poly (L-lactic acid) (PLLA) stent that is receiving growing interest as this is biodegradable in the body and does not require secondary removal surgery. However, acidic byproducts composed of PLLA produced during the biodegradation of the BVS can induce an inflammatory response. Magnesium hydroxide, a basic inorganic particle, neutralizes the acidic byproducts of PLLA. METHODS: In this study, we investigated using a BVS coated with everolimus and surface-modified magnesium hydroxide that suppresses smooth muscle cell proliferation and protects endothelial cells, respectively. The various characteristics of the functional stent were evaluated using in vitro and in vivo analyses. RESULTS: The BVS was successfully prepared with evenly coated everolimus and surface-modified magnesium hydroxide. A neutral pH value was maintained by magnesium hydroxide during degradation, and everolimus was released for one month. The coated BVS effectively inhibited protein adsorption and platelet adhesion, demonstrating excellent blood compatibility. In vitro analysis showed that BVS protects endothelial cells with magnesium hydroxide and selectively inhibits smooth muscle cell proliferation via everolimus treatment. The functional BVS was inserted into porcine coronary arteries for 28 days, and the results demonstrated that the restenosis and inflammation greatly decreased and re-endothelialization was enhanced as compared to others.
CONCLUSIONS
This study provides new insights into the design of drug-incorporated BVS stent for coronary artery disease.
PubMed: 36544178
DOI: 10.1186/s40824-022-00334-x -
Nanomaterials (Basel, Switzerland) Jun 2021Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we...
Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D = 75.2 nm) showed a higher bactericidal effect against than larger nanoparticles (D = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that cells treated with NM80 were directly injured.
PubMed: 34208716
DOI: 10.3390/nano11061584 -
Translational Animal Science Jul 2022Our objective was to evaluate the inclusion of calcium-magnesium carbonate [CaMg(CO)] and calcium-magnesium hydroxide [CaMg(OH)] in corn silage-based diets and their...
Our objective was to evaluate the inclusion of calcium-magnesium carbonate [CaMg(CO)] and calcium-magnesium hydroxide [CaMg(OH)] in corn silage-based diets and their impact on ruminal microbiome. Our previous work showed a lower pH and molar proportion of butyrate from diets supplemented with [CaMg(CO)] compared to [CaMg(OH)]; therefore, we hypothesized that ruminal microbiome would be affected by Mg source. Four continuous culture fermenters were arranged in a 4 × 4 Latin square with the following treatments defined by the supplemental source of Mg: 1) (100% MgO, plus sodium sesquicarbonate as a buffer); 2) [100% CaMg(CO)]; 3) [100% CaMg(OH)]; and 4) [50% Mg from CaMg(CO), 50% Mg from CaMg(OH)]. Diet nutrient concentration was held constant across treatments (16% CP, 30% NDF, 1.66 MCal NEl/kg, 0.67% Ca, and 0.25% Mg). We conducted four fermentation periods of 10 d, with the last 3 d for collection of samples of solid and liquid digesta effluents for DNA extraction. Overall, 16 solid and 16 liquid samples were analyzed by amplification of the V4 variable region of bacterial 16S rRNA. Data were analyzed with R and SAS to determine treatment effects on taxa relative abundance of liquid and solid fractions. Correlation of butyrate molar proportion with taxa relative abundance was also analyzed. Treatments did not affect alpha and beta diversities or relative abundance of phylum, class and order in either liquid or solid fractions. At the family level, relative abundance of in solid fraction was lower for CO and CO/OH compared to OH and Control ( < 0.01). For genera, abundance of ( = 0.01) and Lachnospiraceae ND3007 ( < 0.01) (both from Lachnospiraceae family) was lower and unclassified Ruminococcaceae ( = 0.03) was greater in CO than Control and OH in solid fraction; while abundance of ( = 0.10) and Lachnospiraceae FD2005 ( = 0.09) (both from Lachnospiraceae family) and ( = 0.09) tended to decrease in CO compared to Control in liquid fraction. Butyrate molar proportion was negatively correlated to Ruminococcaceae ( = -0.55) in solid fraction and positively correlated to ( = 0.61) and Lachnospiraceae FD2005 ( = 0.61) in liquid. Our results indicate that source of Mg has an impact on bacterial taxa associated with ruminal butyrate synthesis, which is important for epithelial health and fatty acid synthesis.
PubMed: 35912064
DOI: 10.1093/tas/txac092 -
Nanomaterials (Basel, Switzerland) Feb 2023Although various caries-preventive agents have been developed, dental caries is still a leading global disease, mostly caused by biological factors such as mutans...
Although various caries-preventive agents have been developed, dental caries is still a leading global disease, mostly caused by biological factors such as mutans streptococci. Magnesium hydroxide nanoparticles have been reported to exhibit antibacterial effects; however, they are rarely used in oral care practical applications. In this study, we examined the inhibitory effect of magnesium hydroxide nanoparticles on biofilm formation by and -two typical caries-causing bacteria. Three different sizes of magnesium hydroxide nanoparticles (NM80, NM300, and NM700) were studied, all of which inhibited biofilm formation. The results showed that the nanoparticles were important for the inhibitory effect, which was not influenced by pH or the presence of magnesium ions. We also determined that the inhibition process was mainly contact inhibition and that medium (NM300) and large (NM700) sizes were particularly effective in this regard. The findings of our study demonstrate the potential applications of magnesium hydroxide nanoparticles as caries-preventive agents.
PubMed: 36903742
DOI: 10.3390/nano13050864 -
Frontiers in Endocrinology 2022To describe the current knowledge on thyroid hormonal profile in patients on liquid L-T4 therapy and drugs known to interfere with L-T4 absorption. (Review)
Review
PURPOSE
To describe the current knowledge on thyroid hormonal profile in patients on liquid L-T4 therapy and drugs known to interfere with L-T4 absorption.
METHODS
A PubMed/MEDLINE, Web of Science, and Scopus research was performed. Case reports, case series, original studies and reviews written in English and published online up to 31 August 2022 were selected and reviewed. The final reference list was defined based on the relevance of each paper to the scope of this review.
RESULTS
The available data showed that novel levothyroxine formulations circumvent gastric pH impairment due to multiple interfering drugs such as proton pump inhibitors, calcium or iron supplements, sevelamer, aluminum/magnesium hydroxide and sodium alginate.
CONCLUSION
New formulations can be taken simultaneously with drugs interfering with L-T4 absorption, in particular liquid formulations. Softgel capsules need more studies to support these data.
Topics: Humans; Thyroxine; Drug Compounding; Thyroid Gland; Capsules; Proton Pump Inhibitors
PubMed: 36561558
DOI: 10.3389/fendo.2022.1080108 -
FEBS Letters Oct 2017Inorganic pyrophosphatases (PPases) convert pyrophosphate (PP ) to phosphate and are present in all cell types. Soluble PPases belong to three nonhomologous families, of... (Review)
Review
Inorganic pyrophosphatases (PPases) convert pyrophosphate (PP ) to phosphate and are present in all cell types. Soluble PPases belong to three nonhomologous families, of which Family II is found in approximately a quarter of prokaryotic organisms, often pathogenic ones. Each subunit of dimeric canonical Family II PPases is formed by two domains connected by a flexible linker, with the active site located between the domains. These enzymes require both magnesium and a transition metal ion (manganese or cobalt) for maximal activity and are the most active (k ≈ 10 s ) among all PPase types. Catalysis by Family II PPases requires four metal ions per substrate molecule, three of which form a unique trimetal center that coordinates the nucleophilic water and converts it to a reactive hydroxide ion. A quarter of Family II PPases contain an autoinhibitory regulatory insert formed by two cystathionine β-synthase (CBS) domains and one DRTGG domain. Adenine nucleotide binding either activates or inhibits the CBS domain-containing PPases, thereby tuning their activity and, hence, PP levels, in response to changes in cell energy status (ATP/ADP ratio).
Topics: Adenine Nucleotides; Bacteria; Biocatalysis; Catalytic Domain; Cobalt; Eukaryotic Cells; Gene Expression; Inorganic Pyrophosphatase; Isoenzymes; Kinetics; Magnesium; Manganese; Models, Molecular; Protein Domains; Protein Multimerization; Protein Structure, Secondary; Protein Structure, Tertiary; Protein Subunits
PubMed: 28986979
DOI: 10.1002/1873-3468.12877