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Molecules (Basel, Switzerland) Sep 2022Use of iron-based catalysts in atom transfer radical polymerization (ATRP) is very interesting because of the abundance of the metal and its biocompatibility. Although...
Use of iron-based catalysts in atom transfer radical polymerization (ATRP) is very interesting because of the abundance of the metal and its biocompatibility. Although the mechanism of action is not well understood yet, iron halide salts are usually used as catalysts, often in the presence of nitrogen or phosphorous ligands (L). In this study, electrochemically mediated ATRP (eATRP) of methyl methacrylate (MMA) catalyzed by FeCl3, both in the absence and presence of additional ligands, was investigated in dimethylformamide. The electrochemical behavior of FeCl3 and FeCl3/L was deeply investigated showing the speciation of Fe(III) and Fe(II) and the role played by added ligands. It is shown that amine ligands form stable iron complexes, whereas phosphines act as reducing agents. eATRP of MMA catalyzed by FeCl3 was investigated in different conditions. In particular, the effects of temperature, catalyst concentration, catalyst-to-initiator ratio, halide ion excess and added ligands were investigated. In general, polymerization was moderately fast but difficult to control. Surprisingly, the best results were obtained with FeCl3 without any other ligand. Electrogenerated Fe(II) effectively activates the dormant chains but deactivation of the propagating radicals by Fe(III) species is less efficient, resulting in dispersity > 1.5, unless a high concentration of FeCl3 is used.
Topics: Amines; Catalysis; Dimethylformamide; Ferrous Compounds; Iron; Ligands; Methacrylates; Methylmethacrylate; Nitrogen; Polymerization; Reducing Agents; Salts
PubMed: 36234849
DOI: 10.3390/molecules27196312 -
International Orthopaedics 1999
Review
Topics: Arthroplasty, Replacement, Hip; Bone Cements; Burns, Chemical; Femoral Nerve; Humans; Intraoperative Complications; Jurisprudence; Methylmethacrylate; Mononeuropathies; Nerve Compression Syndromes; Obturator Nerve; Paralysis; Peripheral Nervous System Diseases; Peroneal Nerve; Reoperation; Risk Assessment; Sciatic Nerve; Wounds, Penetrating
PubMed: 10486021
DOI: 10.1007/s002640050329 -
British Medical Journal (Clinical... Sep 1981
Topics: Bone Cements; Bone Neoplasms; Fracture Fixation, Internal; Fractures, Spontaneous; Humans; Methylmethacrylates
PubMed: 6791732
DOI: 10.1136/bmj.283.6294.748 -
Cleveland Clinic Journal of Medicine Feb 2003
Topics: Bone Cements; Braces; Humans; Methylmethacrylate; Osteoporosis; Spinal Fractures
PubMed: 12636338
DOI: 10.3949/ccjm.70.2.88 -
Molecules (Basel, Switzerland) Sep 2022In this research, a new biodegradable and eco-friendly adsorbent, starch-grafted polymethyl methacrylate (St-g-PMMA) was synthesized. The St-g-PMMA was synthesized by a...
In this research, a new biodegradable and eco-friendly adsorbent, starch-grafted polymethyl methacrylate (St-g-PMMA) was synthesized. The St-g-PMMA was synthesized by a free radical polymerization reaction in which methyl methacrylate (MMA) was grafted onto a starch polymer chain. The reaction was performed in water in the presence of a potassium persulfate (KPS) initiator. The structure and different properties of the St-g-PMMA was explored by FT-IR, 1H NMR, TGA, SEM and XRD. After characterization, the St-g-PMMA was used for the removal of MB dye. Different adsorption parameters, such as effect of adsorbent dose, effect of pH, effect of initial concentration of dye solution, effect of contact time and comparative adsorption study were investigated. The St-g-PMMA showed a maximum removal percentage (R%) of 97% towards MB. The other parameters, such as the isothermal and kinetic models, were fitted to the experimental data. The results showed that the Langmuir adsorption and pseudo second order kinetic models were best fitted to experimental data with a regression coefficient of R = 0.93 and 0.99, respectively.
Topics: Adsorption; Free Radicals; Gentamicins; Hydrogen-Ion Concentration; Kinetics; Methacrylates; Methylene Blue; Methylmethacrylates; Polymerization; Polymethyl Methacrylate; Spectroscopy, Fourier Transform Infrared; Starch; Water; Water Pollutants, Chemical
PubMed: 36144579
DOI: 10.3390/molecules27185844 -
Cleveland Clinic Journal of Medicine Feb 2003New drugs to treat osteoporosis, along with two new minimally invasive surgical procedures, are important options for preventing vertebral compression fractures and... (Review)
Review
New drugs to treat osteoporosis, along with two new minimally invasive surgical procedures, are important options for preventing vertebral compression fractures and treating severe back pain and disability. However, the mainstay treatments remain cautious use of analgesics, limited bed rest, and physical rehabilitation.
Topics: Bone Cements; Braces; Humans; Methylmethacrylate; Osteoporosis; Spinal Fractures
PubMed: 12636346
DOI: 10.3949/ccjm.70.2.147 -
Journal of General Internal Medicine Feb 2017
Topics: Adenocarcinoma; Aged, 80 and over; Fatal Outcome; Humans; Lung Neoplasms; Male; Methylmethacrylate; Prostheses and Implants; Radiography, Thoracic; Terminal Care; Tomography, X-Ray Computed; Tuberculosis, Pulmonary
PubMed: 27488968
DOI: 10.1007/s11606-016-3828-6 -
Journal of Prosthodontic Research Jul 2023We aimed to evaluate the effectiveness of photoreactive 2-methacryloyloxyethyl phosphorylcholine (MPC) in inhibiting Candida albicans biofilm formation on polymethyl...
PURPOSE
We aimed to evaluate the effectiveness of photoreactive 2-methacryloyloxyethyl phosphorylcholine (MPC) in inhibiting Candida albicans biofilm formation on polymethyl methacrylate (PMMA) and assess its mechanism and need for re-application by evaluating its interaction with salivary mucin and durability during temperature changes.
METHODS
PMMA discs were used as specimens. The MPC coating was applied using the spray and cure technique for the treatment groups, whereas no coating was applied to the control. The MPC treatment (MT) groups were further differentiated based on the number of thermal cycles involved (0, 1000, 2500, and 5000). The optical density was measured to assess mucin adsorption (MA). Contact angle (CA) was calculated to evaluate surface hydrophilicity. The presence of MPC components on the PMMA surface was assessed using X-ray photoelectron spectroscopy (XPS). C. albicans biofilms were evaluated qualitatively (scanning electron microscope images) and quantitatively (colony-forming units (CFUs)). Statistical analysis was conducted using two-way analysis of variance and Tukey's multiple comparison test.
RESULTS
MA rate and CA increased significantly in the MT groups, which exhibited significantly fewer CFUs and thinner biofilms than those of the control group. Based on the XPS, MA, and CFU evaluations, the durability and efficacy of the MPC coating were considered stable up to 2500 thermal cycles. Additionally, a significant interaction was observed between mucin concentration and MPC efficacy.
CONCLUSIONS
The photoreactive MPC coating, which was resistant to temperature changes for approximately 3 months, effectively prevented C. albicans biofilm formation by modifying surface hydrophilicity and increasing mucin adsorption.
Topics: Candida albicans; Acrylic Resins; Polymers; Polymethyl Methacrylate; Surface Properties; Biofilms; Mucins
PubMed: 36288959
DOI: 10.2186/jpr.JPR_D_22_00102 -
PloS One 2018The high-throughput, label-free Corning Epic assay has applications in drug discovery, pharmacogenomics, cell receptor signaling, cell migration, and viral titration....
The high-throughput, label-free Corning Epic assay has applications in drug discovery, pharmacogenomics, cell receptor signaling, cell migration, and viral titration. The utility of Epic technology for biocompatibility testing has not been well established. In manufacturing of medical devices, in vitro and in vivo biocompatibility assessments are mandatory, according to ISO 10993. The new medical device regulation MDR 745/2017 specifies that ex vivo assays that can closely recapitulate in vivo scenarios are needed to better evaluate biomedical devices. We propose herein that Epic technology-which enables detection of variations in cell mass distribution-is suitable for biocompatibility screening of compounds. In this study, we challenged primary human osteoblasts, endothelial cells, and neurons derived from induced pluripotent stem cells with specific concentrations of methyl methacrylate (MMA). Polymeric MMA has long been applied in cranioplasty, where it makes contact with multiple cell types. Application of Epic technology yielded real-time cytotoxicity profiles for all considered cell types. The results were compared with those from microscopic observation of the same culture plate used in the Epic analyses. The Epic assay should be further examined for its utility for cell biology, genomics, and proteomics companion assays. Our results suggest that Epic technology can be applied to biocompatibility evaluation of human cells in medical device development.
Topics: Cell Differentiation; Drug Evaluation, Preclinical; Humans; Induced Pluripotent Stem Cells; Mesenchymal Stem Cells; Methylmethacrylate; Neurons; Primary Cell Culture
PubMed: 30180158
DOI: 10.1371/journal.pone.0201671 -
Indian Journal of Dental Research :... 2016The objective of this study was to compare the sorption and solubility of heat-cure and self-cure acrylic resins in different solutions. (Comparative Study)
Comparative Study
OBJECTIVE
The objective of this study was to compare the sorption and solubility of heat-cure and self-cure acrylic resins in different solutions.
MATERIALS AND METHODS
One heat-cure acrylic resin (Trevalon) and one self-cure acrylic resin (Rapid Repair) were studied. Five groups of square-shaped specimens (20 mm × 20 mm × 2 mm) were prepared for each acrylic resin and then immersed in five solutions: distilled water, artificial saliva, denture cleansing solution, distilled water, and denture cleaning solution for 12 h alternatively, artificial saliva and denture cleaning solution for 12 h alternatively at 37 ± 2°C, and tested sorption and solubility by weight gain/loss method, respectively, after 1, 6, and 11 weeks. The data were analyzed by one-way analysis of variance followed by post hoc Tukey's test.
RESULTS
Water sorption mean values varied from 17.5 ± 0.88 to 27.25 ± 1.04 μg/mm 3 for heat cure and from 12.75 ± 0.55 to 19.75 ± 1.04 μg/mm 3 for self-cure in the different solutions after different interval periods of 1, 6, and 11 weeks. These values were statistically significant (P< 0.001). Water solubility mean values varied from 0.25 ± 0.55 to 1.5 ± 0.55 μg/mm 3 for heat cure and from 1.5 ± 0.55 to 6.5 ± 0.55 μg/mm 3 for self-cure in the different solutions after different interval periods of 1, 6, and 11 weeks. These values were statistically not significant (P > 0.05). There was no linear correlation between sorption and solubility values. Overall, analysis of results showed the maximum sorption value in denture cleansing solution followed by alternative soaking in distilled water and artificial saliva. Least sorption was observed with artificial saliva followed by distilled water.
CONCLUSION
Both heat-cure and self-cure acrylic resins showed varying water sorption and solubility. The results of both water sorption and solubility showed compliance with the International Standards Organization specification. No correlation was found between water sorption and solubility. Artificial saliva solution is a better storage medium than distilled water and denture cleansing solution for both heat-cure and self-cure acrylic resins.
Topics: Acrylic Resins; Denture Cleansers; Hot Temperature; Materials Testing; Methylmethacrylates; Saliva, Artificial; Solubility; Solutions; Water
PubMed: 27411658
DOI: 10.4103/0970-9290.186234