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OBJECTIVE: To characterize patients with methylmethacrylate embolism. METHODOLOGY: Systematic literature search of clinical cases according to the PRISMA 20 statement and the Cochrane Handbook of Systematic Reviews of Interventions (version 5.1.022). The population with a diagnosis of embolism or vascular complications due to bone cement (methyl methacrylate) reported in publications from 1992 to 2019 was included, with analysis of sociodemographic, clinical, and paraclinical characteristics. RESULTS: The most common procedure was vertebroplasty (77%), mostly in women (74.3%); 63.5% were symptomatic patients and the pulmonary artery was the most common site (89.2%). All patients received anticoagulants and the mortality rate was 9%. CONCLUSIONS: Women have a higher risk of methylmethacrylate embolism after interventions such as vertebroplasty, with a higher prevalence of pulmonary clinical presentation due to embolus at this level and detected postoperatively; however, unlike what is described in the literature, there was a higher incidence of symptomatic patients. In the reported cases, medical treatment consisted of the administration of anticoagulants, mainly heparin, so that the reported mortality figures were low. [ABSTRACT FROM AUTHOR]

Objective: Unusual or unexpected effect of treatment Background: Vertebroplasty is a minimally invasive radiological procedure that involves injection of cement to stabilize the fractured vertebra. It has also been increasingly used to relieve pain in patients with bone-incorporated malignancies. The most frequently encountered complication of this procedure is inadvertent cement leakage, which has the potential to embolize. This report presents an incidental finding of cement embolism during fluoroscopy for a peripherally inserted central catheter (PICC) line 4 weeks after vertebroplasty in a 50-year-old man with multiple myeloma. Case Report: Our report details the case of a 50-year-old man who presented for progressive sciatic nerve pain and was found on imaging to have an L3 fracture, spinal stenosis, lumbar spinal spondylosis, and diffusely decreased bone density, eventually diagnosed with multiple myeloma. For symptomatic relief and vertebrae stabilization, he underwent a CT-guided fluoroscopic vertebroplasty procedure. Four weeks later, during fluoroscopy for a PICC, he was incidentally found to have radiopaque opacities within the pulmonary arteries. He was diagnosed with a pulmonary embolism due to transvertebral cement leakage from his vertebroplasty. Given the central nature of his embolism, he was treated with anticoagulation and closely monitored. Throughout the treatment period, he remained asymptomatic with normal vital signs and NT-brain natriuretic peptide. Conclusions: This report highlights the association between vertebroplasty and pulmonary cement embolism (PCE), the potential for late detection upon chest imaging even weeks after vertebroplasty, and suggests that some patients with PCE may need therapeutic anticoagulation. [ABSTRACT FROM AUTHOR]

Background Residual monomer tests using high-performance liquid chromatography and cytotoxicity tests were performed to analyze the effect on the oral mucosa of a self-curing resin for provisional crown production. Methods A cytotoxicity test was performed to confirm whether leaked residual monomers directly affected oral mucosal cells. The cytotoxicity of the liquid and solid resin polymers was measured using a water-soluble tetrazolium (WST) test and microplate reader. Results In the WST assay using a microplate reader, 73.4% of the cells survived at a concentration of 0.2% liquid resin polymer. The cytotoxicity of the liquid resin polymer was low at ≤0.2%. For the solid resins, when 100% of the eluate was used from each specimen, the average cell viability was 91.3% for the solid resin polymer and 100% for the hand-mixed self-curing resin, which is higher than the cell viability standard of 70%. The cytotoxicity of the solid resin polymer was low. Conclusion Because the polymerization process of the self-curing resin may have harmful effects on the oral mucosa during the second and third stages, the solid resin should be manufactured indirectly using a dental model.

The goal of the current study was to determine the mechanical proprieties of polymethylmethacrylate (PMMA) and the improved compound, the graphene-based PMMA, with Zn and Ag and to compare the results. Scanning electron microscopy analysis of the samples before and after the mechanical test was conducted. The compression behavior, flexural properties, tensile strength, and shape of the samples were all investigated and compared between the variants of PMMA. Commercially available polymethylmethacrylate was used (Orthocryl®—Dentaurum, Ispringen, Germany) with the salt and pepper technique according to the manufacturer's instructions to produce 20 samples for each mechanical trial with standard cylinders (4 mm diameter × 8 mm length) for compression, parallelepipedal prisms for flexing (2 mm × 2 mm × 25 mm) and flat samples for traction. There was no statistical difference in the mechanical proprieties of the samples evaluated, although there were values that could suggest significance. The graphene-based PMMA demonstrated good mechanical proprieties, like the commercially available PMMA, and appears promising for future clinical use based on its multiple advantages. [ABSTRACT FROM AUTHOR]

Gas-phase combustion of methylmethacrylate (MMA) monomer is an essential stage of solid polymethylmethacrylate (PMMA) combustion, which is of interest in many applications. A skeletal kinetic scheme for MMA combustion in air is proposed including 44 irreversible elementary reactions for 29 species. The mechanism is derived from the reduced kinetic scheme for MMA oxidation comprised of 263 reactions for 66 components. In this work, the mechanism predictive capabilities are demonstrated by solving the self-ignition problem, as well as the premixed flame propagation problem for MMA-air mixtures. It is shown that the skeletal mechanism overpredicts the ignition delay times due to significant simplification of the MMA decomposition stage reaction pathways. The flame propagation speed is predicted reasonably for lean and nearly-stoichiometric mixtures, but overpredicted for fuel-rich mixtures. Also, a diffusion flame representing the cup burner of liquid MMA is simulated in two-dimensional statement of the problem, the results are shown to agree well with the measurements and numerical simulations performed earlier on the basis of a detailed kinetic scheme. The skeletal mechanism can be used in the numerical simulations of gas-phase combustion of MMA, including the problems of flame propagation over the solid PMMA polymer. [ABSTRACT FROM AUTHOR]

Acrylic bone cement is widely used in orthopedic surgery for treating various conditions of the bone and joints. Bone cement consists of methyl methacrylate (MMA), polymethyl methacrylate (PMMA), and benzoyl peroxide (BPO), functioning as a liquid monomer, solid phase, and polymerization initiator, respectively. However, cell and tissue toxicity caused by bone cement has been a concern. This study aimed to determine the effect of tri-n-butyl borane (TBB) as an initiator on the biocompatibility of bone cement. Rat spine bone marrow-derived osteoblasts were cultured on two commercially available PMMA-BPO bone cements and a PMMA-TBB experimental material. After a 24-h incubation, more cells survived on PMMA-TBB than on PMMA-BPO. Cytomorphometry showed that the area of cell spread was greater on PMMA-TBB than on PMMA-BPO. Analysis of alkaline phosphatase activity, gene expression, and matrix mineralization showed that the osteoblastic differentiation was substantially advanced on the PMMA-TBB. Electron spin resonance (ESR) spectroscopy revealed that polymerization radical production within the PMMA-TBB was 1/15-1/20 of that within the PMMA-BPO. Thus, the use of TBB as an initiator, improved the biocompatibility and physicochemical properties of the PMMA-based material.

Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity and is cytotoxic. Implant loosening and toxic complications are significant and recognized problems. Here we devised two strategies to improve PMMA-based bone cement: (1) adding 4-methacryloyloxylethyl trimellitate anhydride (4-META) to MMA monomer to render it hydrophilic; and (2) using tri-n-butyl borane (TBB) as a polymerization initiator instead of benzoyl peroxide (BPO) to reduce free radical production. Rat bone marrow-derived osteoblasts were cultured on PMMA-BPO, common bone cement ingredients, and 4-META/MMA-TBB, newly formulated ingredients. After 24 h of incubation, more cells survived on 4-META/MMA-TBB than on PMMA-BPO. The mineralized area was 20-times greater on 4-META/MMA-TBB than PMMA-BPO at the later culture stage and was accompanied by upregulated osteogenic gene expression. The strength of bone-to-cement integration in rat femurs was 4- and 7-times greater for 4-META/MMA-TBB than PMMA-BPO during early- and late-stage healing, respectively. MicroCT and histomorphometric analyses revealed contact osteogenesis exclusively around 4-META/MMA-TBB, with minimal soft tissue interposition. Hydrophilicity of 4-META/MMA-TBB was sustained for 24 h, particularly under wet conditions, whereas PMMA-BPO was hydrophobic immediately after mixing and was unaffected by time or condition. Electron spin resonance (ESR) spectroscopy revealed that the free radical production for 4-META/MMA-TBB was 1/10 to 1/20 that of PMMA-BPO within 24 h, and the substantial difference persisted for at least 10 days. The compromised ability of PMMA-BPO in recruiting cells was substantially alleviated by adding free radical-scavenging amino-acid N-acetyl cysteine (NAC) into the material, whereas adding NAC did not affect the ability of 4-META/MMA-TBB. These results suggest that 4-META/MMA-TBB shows significantly reduced cytotoxicity compared to PMMA-BPO and induces osteoconductivity due to uniquely created hydrophilic and radical-free interface. Further pre-clinical and clinical validations are warranted.

BackgroundChemicals in nail products have been linked to numerous health concerns.MethodsWe recruited Vietnamese-American nail salon owners and workers in California and randomized salons into an intervention or control group. Owners in the intervention group received training and then provided education to workers in their salons on best practices to reduce workplace chemical exposures. Methyl methacrylate (MMA), toluene, and total volatile organic compounds (TVOCs) were measured using personal air monitors worn by workers during the work-shift.ResultsWe enrolled 77 salons (37 intervention and 40 control) and 200 workers. There was no significant intervention effect between the two groups. However, MMA and TVOCs were higher for workers who used gel polish and acrylic nails as well as in busy salons.ConclusionsAlthough the intervention did not show reductions in chemical levels, identifying worker tasks and salon characteristics that predict chemical levels can inform future interventions to reduce exposures.

This work reports the preparation of hydrogel nanocomposites based on copolymerization of methyl methacrylate using ammonium persulfate as the initiator, methylene bisacrylic amide as the crosslinker & various amounts of functionalized CNT for inter-hydrogel binding. Functionalization of CNTs was performed by its oxidation at room temperature using nitric acid as the oxidizing agent, then acylation of carboxylic acid agent in CNTs by SOCl2 addition and finally esterification of CNTs by the addition of ethylene glycol to acylchloride. The swelling rate of the obtained composites was checked in deionized water where the composite containing more CNTs percent in the hydrogel structure showed a higher swelling rate (>50%).Then, for increase of chemical activity, the obtained hydrogel nanocomposites were impregnated by solution of CuSO4 with different concentrations and the resultant hydrogels as the activity filler were analyzed by FTIR, XRD and SEM. [ABSTRACT FROM AUTHOR]

Debonding of the artificial acrylic tooth from a denture base resin of a complete denture is a critical situation requiring substantial repair. Thus, improving the bond strength between artificial acrylic teeth and denture base resins (DBRs) is essential to prevent this clinical issue. Therefore, the aim of this study was to investigate the effect of surface treatments on the shear bond strength between artificial acrylic teeth and denture base resin fabricated from the 3D-printing method. A total of 50 cylindrical 3D-printed artificial acryl teeth were divided into 5 groups (n=10), in which the surface of the teeth was treated as follows; 1) no surface treatment (control), 2) air abrasion, 3) methylmethacrylate (MMA), 4) MMA and post-cured with heat polymerization, and 5) a combination of air abrasion and MMA. All specimens were tested for the shear bond strength using a universal testing machine. The mode of failure was observed under a stereomicroscope. Oneway analysis of variance (ANOVA) and Tukey's multiple comparisons was used for analyzing data. The mean shear bond strength of all experimental groups was statistically significant different (p<0.0001), except for the groups treated with either air abrasion or MMA (p>0.999). Specimens treated with MMA and post-cured with heat polymerization exhibited the greatest shear bond strength. Surface-treated specimens showed a high percentage of mixed failure where cohesive and adhesive failures coincided. The greatest shear bond strength was observed in denture base resins bonded to the artificial acrylic teeth treated with MMA and post-cured with heat polymerization. This could be considered as an alternative method to enhance the bond strength in a 3D-printed complete denture. [ABSTRACT FROM AUTHOR]

The goal of the current study was to determine the mechanical proprieties of polymethylmethacrylate (PMMA) and the improved compound, the graphene-based PMMA, with Zn and Ag and to compare the results. Scanning electron microscopy analysis of the samples before and after the mechanical test was conducted. The compression behavior, flexural properties, tensile strength, and shape of the samples were all investigated and compared between the variants of PMMA. Commercially available polymethylmethacrylate was used (Orthocryl®—Dentaurum, Ispringen, Germany) with the salt and pepper technique according to the manufacturer’s instructions to produce 20 samples for each mechanical trial with standard cylinders (4 mm diameter × 8 mm length) for compression, parallelepipedal prisms for flexing (2 mm × 2 mm × 25 mm) and flat samples for traction. There was no statistical difference in the mechanical proprieties of the samples evaluated, although there were values that could suggest significance. The graphene-based PMMA demonstrated good mechanical proprieties, like the commercially available PMMA, and appears promising for future clinical use based on its multiple advantages.

Abstract Background There is little evidence on techniques for management of peri-prosthetic infection (PJI) in the context of severe proximal femoral bone loss. Custom-made articulating spacers (CUMARS) utilising cemented femoral stems as spacers was described providing better bone support and longer survival compared to conventional articulating spacers. We retrospectively report our experience managing PJI by adaptation of this technique using long cemented femoral stems where bone loss precludes use of standard stems. Methods Patients undergoing 1st stage revision for infected primary and revision THA using a cemented long stem (> 205 mm) and standard all-polyethylene acetabulum between 2011 and 2018 were identified. After excluding other causes of revision (fractures or aseptic loosening), Twenty-one patients remained out of total 721 revisions. Medical records were assessed for demographics, initial microbiological and operative treatment, complications, eradication of infection and subsequent operations. 2nd stage revision was undertaken in the presence of pain or subsidence. Results Twenty-one patients underwent 1st stage revision with a cemented long femoral stem. Mean follow up was 3.9 years (range 1.7–7.2). Infection was eradicated in 15 (71.4%) patients. Two patients (9.5%) required repeat 1st stage and subsequently cleared their infection. Three patients (14.3%) had chronic infection and are on long term suppressive antibiotics. One patient (4.8%) was lost to follow up before 2 years. Complications occurred in seven patients (33%) during or after 1st stage revision. Where infection was cleared, 2nd stage revision was undertaken in 12 patients (76.5%) at average of 9 months post 1st stage. Five (23.8%) CUMARS constructs remained in-situ at an average of 3.8 years post-op (range 2.6–5.1). Conclusions Our technique can be used in the most taxing of reconstructive scenarios allowing mobility, local antibiotic delivery, maintenance of leg length and preserves bone and soft tissue, factors not afforded by alternative spacer options.

Background: Chest-wall sarcomas are treated with extensive resections and complex defect reconstruction to restore chest-wall integrity. It is a difficult surgical procedure that incorporates a multidisciplinary approach for the best outcome, preventing paradoxical chest movement issues and reducing complications., Objective: We aimed to describe our experience of chest-wall reconstruction using polypropylene mesh (Marlex® Mesh) combined with methyl-methacrylate and soft-tissue coverage with a latissimus dorsi flap following sarcoma resection., Patients and Methods: Among the 53 patients treated for primary chest-wall sarcomas at the European Institute of Oncology (IEO) in Milan, Italy, from 1998 to 2020, 14 cases underwent chest-wall resection and reconstruction using polypropylene mesh, methyl-methacrylate and the latissimus dorsi flap. Patients with locally advanced breast cancers, locally advanced lung cancers, squamous cell carcinomas, and other secondary chest-wall malignancies were excluded from the study, as were the patients with different types of chest-wall reconstruction., Results: In this study, 14 patients (6 men and 8 women) with various primary chest-wall sarcomas were enrolled. On an average, 2 ribs (range: 1-5) were removed during the surgeries, and the chest-wall defects ranged from 20 to 150 cm 2 with an average size of 73 cm 2 . The mean follow-up period for these patients was approximately 63.80 months CONCLUSION: The combination of Marlex® mesh filled with methyl-methacrylate and covered using latissimus dorsi myocutaneous flap provides safe, low-cost and effective single-stage chest-wall reconstruction after surgery for primary sarcomas., (Copyright © 2024 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: Calvarial epidermoid cysts (EC) are encased remnants of ectoderm at the third week of gestation. There are also reports which consider them sequelae of head trauma. They are benign lesions. As they develop, they exert a mass effect to adjacent anatomical structures. Case Report: We report the case of a 58-year-old male patient with left-sided exophthalmos. His radiologic examinations depicted an oval cystic lesion (7×5×5.5 cm) arising from the left frontal bone and abutting the ipsilateral orbital roof. Our patient underwent a total extirpation of the lesion through a frontal craniectomy. Cranioplasty was then performed with a Porex® graft. The pearl-hued lamellae of the lesion macroscopically resembled keratin tissue. Histopathological findings supported the diagnosis of an epidermoid cyst. Postoperatively, our patient had no neurologic deficits and a computed tomography scan showed no residual effects. Conclusions: Large calvarial EC with intraorbital expansion in adults are rare clinical entities. Gross total resection with the infiltrated bone and cranioplasty is the treatment of choice, which also establishes the diagnosis. [ABSTRACT FROM AUTHOR]

In order to obtain porphyrin-containing polymers, the copolymerization of acrylate monomers of the various structures with natural porphyrin, namely methyl pheophorbide a (MPP) and its complex with copper (CuMPP) in tetrahydrofuran and toluene was studied. The copolymers of methyl methacrylate (MMA) with MPP or CuMPP, glycidyl methacrylate (GMA) with MPP or CuMPP having different compositions were synthesized. The influence of the nature of the solvent, the initial mass ratio of the monomers during copolymerization on the structure, composition, and properties of the obtained compounds were investigated. The study of the physico-chemical, molecular weight, structural, and chemical characteristics of the prepared copolymers was carried out. The possibility of controlled synthesis of the copolymers with controlled molecular weight characteristics by varying the parameters of the reaction medium was shown. [ABSTRACT FROM AUTHOR]

Study Design: Prospective. Purpose: Over past one and half decade, ready-to-use magnetic resonance imaging (MRI) compatible spinal implants have changed the clinical practice and economics of spinal surgery. These are beyond reach of majority of population of developing countries like India due to financial reasons and also availability in remote areas. There is a growing need for a MRI compatible cost-effective spinal implant of proven quality. The authors used bone cement spacers for the said purpose for various level spine surgeries. Overview of Literature: Methylmethacrylate, known as bone cement, was used extensively for spinal surgeries from craniovertebral junction to sacrum for augmentation and replacement of various spinal elements. Its biochemical and biomechanical properties were tested for safe clinical use and was a favored material for spinal surgeons. Materials and Methods: The authors made molds for making bone cement spacers for various spine levels with the help of silicone material. Results: Sixteen patients (12 males, 4 females with an average age of 31 years) of various spine level surgeries were done where bone cement spacers were used. It included patients of basilar invagination (n = 9), dorsal Pott's disease (n = 1), lumbar (n = 2), and lumbo-sacral spondylolisthesis (n = 1). Spacers could be used without any difficulties and postoperative day 1- and 3-months follow-up computed tomography scan of the patients revealed no change in the dimensions of the spacer and fusion at 3 months of operated levels. Conclusion: The authors feel that bone cement spacers may be an effective and low-cost alternative to the existing costly alternatives. [ABSTRACT FROM AUTHOR]

Background: There is little evidence on techniques for management of peri-prosthetic infection (PJI) in the context of severe proximal femoral bone loss. Custom-made articulating spacers (CUMARS) utilising cemented femoral stems as spacers was described providing better bone support and longer survival compared to conventional articulating spacers. We retrospectively report our experience managing PJI by adaptation of this technique using long cemented femoral stems where bone loss precludes use of standard stems.Methods: Patients undergoing 1st stage revision for infected primary and revision THA using a cemented long stem (> 205 mm) and standard all-polyethylene acetabulum between 2011 and 2018 were identified. After excluding other causes of revision (fractures or aseptic loosening), Twenty-one patients remained out of total 721 revisions. Medical records were assessed for demographics, initial microbiological and operative treatment, complications, eradication of infection and subsequent operations. 2nd stage revision was undertaken in the presence of pain or subsidence.Results: Twenty-one patients underwent 1st stage revision with a cemented long femoral stem. Mean follow up was 3.9 years (range 1.7-7.2). Infection was eradicated in 15 (71.4%) patients. Two patients (9.5%) required repeat 1st stage and subsequently cleared their infection. Three patients (14.3%) had chronic infection and are on long term suppressive antibiotics. One patient (4.8%) was lost to follow up before 2 years. Complications occurred in seven patients (33%) during or after 1st stage revision. Where infection was cleared, 2nd stage revision was undertaken in 12 patients (76.5%) at average of 9 months post 1st stage. Five (23.8%) CUMARS constructs remained in-situ at an average of 3.8 years post-op (range 2.6-5.1).Conclusions: Our technique can be used in the most taxing of reconstructive scenarios allowing mobility, local antibiotic delivery, maintenance of leg length and preserves bone and soft tissue, factors not afforded by alternative spacer options. [ABSTRACT FROM AUTHOR]

Objective: To determine the effects of using K18-methyl methacrylate (K18-MMA) and K18-Filler on composite cure, esthetic, mechanical, polymerization shrinkage, and antimicrobial properties., Methods: K18-MMA (0-20% w/w) was used to replace TEGDMA in a 70:30 Bis-GMA:TEGDMA composite filled to 70% w/w with barium glass or K18-Filler. Composite degree of cure (Rockwell 15T hardness and near Infrared FTIR), hydrophilicity (contact angle measurements), translucency (transparency parameter measurements, TP), mechanical (3-point bend test), polymerization shrinkage (volumetric shrinkage and shrinkage stress), and antimicrobial properties (colony counting assay) against Streptococcus mutans, Streptococcus sanguinis, and Candida albicans were determined., Results: All experimental groups had comparable degrees of cure (near Infrared FTIR and Rockwell 15T Hardness), TP, moduli, polymerization volumetric shrinkages and shrinkage stresses to those of controls (Bonferroni corrected p > 0.0018). Only one group (15% K18-MMA+K18-Filler) had significantly different (lower) contact angles as compared to that of controls (Bonferroni corrected p < 0.0018). Most of the K18-Filler-containing composites had significantly lower ultimate transverse strengths (UTS) than controls (Bonferroni corrected p < 0.0018). Controls had significantly greater S mutans colony counts than 15% and 20% w/w K18-MMA+K18-Filler groups, and greater S sanguinis and C albicans colony counts than K18-containing groups. Of the composites with that provided significant antimicrobial properties against S. mutans, S. sanguinis, and C. albicans, only the 20% K18-MMA+K18-Filler group had significantly lower UTS than controls., Significance: Composites with K18-MMA and K18-Filler with comparable physical properties to control composites and significant antimicrobial properties have been developed. K18-MMA and K18-Filler seem to be suitable for incorporation into commercial dental resins., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background/Aim. Autopolymerized, or cold polymerized poly(methyl methacrylate) class of materials have a lower mechanical properties compared to hot polymerized poly(methyl methacrylate), due to a limited time of mixing before the polymerization process begins. The aim of this study was to test the effect of different relatively low nanosilica contents, in improving mechanical properties of the cold polymerized poly(methyl methacrylate). Methods. A commercially available autopolymerized poly(methyl methacrylate) denture reline resin methyl methacrylate liquid component was mixed with 7 nm after treated hydrophobic fumed silica and subsequently mixed with poly(methyl methacrylate) powder. Three nanosilica loadings were used: 0.05%, 0.2% and 1.5%. Flexural modulus and strength were tested, with one way ANOVA followed by Tukey’s test. Furthermore, zeta potential, differential scanning calorimetry, scaning electrone microscopy and energy dispersive X-ray analyses were performed. Results. Flexural modulus and strength of poly(methyl methacrylate) based nanocomposites were statistically significantly increased by the addition of 0.05% nano-SiO2. The increase in nanosilica content up to 1.5% does not contribute to mechanical properties tested, but quite contrary. The main reason was agglomeration, that occurred before mixing of the liquid and powder component and was proved by zeta potential measurement, and after mixing, proved by scanning electrone microscopy and energy dispersive x-ray analyses. Conclusions. Addition of 7 nm 0.05% SiO2 is the most effective in increasing flexural modulus and strength of autopolimerized poly(methyl methacrylate).

Background: Autoimmune/inflammatory syndrome induced by adjuvants has been associated with different substances used for cosmetic purposes; for example, silicone, methylmethacrylate, autoimmune disorders and cancer. Discussion: A 40-year-old man with a prior history of methylmethacrylate injection in the buttocks for aesthetic purposes 8 years ago, presented with deep venous thrombosis in the left leg 6 months ago, accompanied with inflammation, hardening, changes in colour, ulceration in the buttocks, arthritis, myalgias and fever. Weak and moderate lupus anticoagulant and low levels of anticardiolipin antibodies were present. Thoracoabdominal tomography showed hepatosplenomegaly and a pulmonary nodule, the biopsy of which showed chronic granulomatous inflammation. After a month, a new chest tomography showed multiple nodular pulmonary lesions. The new pulmonary biopsy showed a diffuse large B-cell non-Hodgkin's lymphoma which was treated with cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab for four cycles, with good response of the autoimmune/inflammatory syndrome, but partial response of the diffuse large B-cell non-Hodgkin's lymphoma. Conclusion: We describe the first case of seronegative antiphospholipid syndrome and lymphoma associated with methylmethacrylate in a patient with autoimmune/inflammatory syndrome. [ABSTRACT FROM AUTHOR]

Zinc sulfide is one of the most popular luminescent semiconductors of the А(II)B(VI) group. Doping of ZnS quantum dots (QDs) with Ln3+ ions makes it possible to form in a semiconductor matrix nanosized structures containing isolated narrowband luminescence centers. Incorporation of QDs into ac-rylate matrices additionally stabilized particles and allows formation of their morphology. The Zn1 ‒x‒yCuxEuyS/EuL3 nanosized structures, where L is a trifluoroacetate anion, are synthesized in situ in methylmethacrylate (MMA) by the method of appearing reagents. Doping of ZnS was performed by introduction of soluble zinc sulfide precursors simultaneously with copper and europium trifluoroacetates into the acrylate reaction mixture. The optically transparent polymer composites PММА/Zn1 –x–yCuxEuyS/EuL3 were obtained by radical casting polymerization of MMA. The excitation of luminescence in the composites is related to electronic interband transitions in ZnS, to the system of levels formed by dopant ions in the ZnS band gap, and to the intrinsic energy absorption by Eu3+ ions. The broadband luminescence of the composites is caused by intracrystalline defects formed in ZnS upon doping. The narrowband luminescence results from the 5D0 → 7Fj electronic transitions of Eu3+ ions bound to QDs and existing in the polymer matrix independently of them. The energy transfer from the donor levels of the semiconductor matrix to the levels of Eu3+ with subsequent luminescence is confirmed by the overlap of the absorption bands of doped ZnS and the luminescence excitation bands of the composites, as well as by an increase in the intensity of the narrowband luminescence of Eu3+ simultaneously with a decrease in the intensity of the broadband recombination luminescence of doped ZnS. The decrease in the intensity of the recombination luminescence of ZnS with increasing concentration of Eu3+ to >1.0 × 10–3 mol/L is also related to the formation of a layer of europium complex compounds on the surface of particles, which hinders the propagation of exciting radiation to the particle core. [ABSTRACT FROM AUTHOR]

Synthetic and natural polymeric esters find applications in transport and construction sectors, where fire safety is an important concern. One polymer that is widely used is poly (methyl methacrylate) (PMMA), which almost completely undergoes thermal decomposition into methyl methacrylate (its monomer) (MMA) at – C. In order to analyze the high-temperature gas-phase oxidation of PMMA, and thereby predict its fire behavior (such as burning rate, temperature of the material, and heat fluxes) with less computational effort, a compact kinetic model for the oxidation of its primary decomposition product, MMA, is most essential. This is accomplished in the present work by obtaining a reduced mechanism for MMA oxidation from a detailed mechanism from the Lawrence Livermore National Laboratories group. To extend the available data base for model validation and present validation data at atmospheric pressure conditions, for the first time, (i) detailed measurements of species profiles have been performed in stoichiometric laminar flat flames using flame sampling molecular beam mass spectrometry (MBMS) technique and (ii) laminar burning velocities have been obtained using the heat flux method for various unburnt mixture temperatures. Evaluating the model against these data sets point to the need to revise the kinetic model, which is achieved by adopting rate constants of key reactions among analogous molecules from recent literature. The updated compact kinetic model is able to predict the major species in the flat flame as well as the burning velocity of MMA satisfactorily. The final "short MMA mechanism" consists of 88 species and 1084 reactions. [ABSTRACT FROM AUTHOR]

Engine oils are widely used for lubrication purposes in automobile and related industries. Viscosity Index (VI) improver has found its largest commercial applications as additives to engine oils. Examples are power steering fluid, aircraft piston engine oils, modern internal-combustion engines, turbine engine oils (stationary and aircraft), and industrial gear oils. Viscosity Index improvers are added in the lube oils to reach the desired Viscosity Index (VI). The enhancement of VI of lube oils (Servoneum 100, Servopress 68, Servomesh SP 220, and Servocut 335) by the addition of viscosity index improvers (Methylmethacrylate (MMA), Polybutadiene rubber (PBR), and Polyisoprene-cis) has been studied. VI of blended oils, made from the lube oils (Servoneum 100, Servopress 68, Servomesh SP 220, and Servocut 335) by the addition of MMA, PBR, and Polyisoprene-cis, has shown the potential to reach the maximum value. It has been found that the occurrence of maximum VI depends on the lube oil used and the type and concentration of viscosity index improver.

Polymethyl methacrylate (PMMA) bone cement is widely used to relieve pain caused by metastatic bone tumors. We previously found that PMMA bone cement containing 15 mass% or more of TiO 2 showed good apatite-forming ability, and 25 mass% or more of Fe 3 O 4 generated sufficient heat for hyperthermia under an alternating current (AC) magnetic field. In this study, the cytocompatibility of PMMA bone cement with Fe 3 O 4 :TiO 2 weight ratios of 25:15 (F25T15-3/2-42) and 30:15 (F30T15-3/2-42) was evaluated using osteoblastic cells (MC3T3-E1). The proliferation and differentiation of MC3T3-E1 cells were suppressed for F25T15-3/2-42 and F30T15-3/2-42 compared to PMMA bone cement without Fe 3 O 4 and TiO 2 (F0T0-3/2-42). The release of methyl methacrylate (MMA) monomers from F25T15-3/2-42 and F30T15-3/2-42 at 7 days was about 33 and 50 times higher than that from F0T0-3/2-42, respectively. The remarkable release of MMA monomers from F25T15-3/2-42 and F30T15-3/2-42 may be responsible for the suppressed proliferation and differentiation of MC3T3-E1 cells. The release of MMA monomers was not reduced when the MMA/PMMA weight ratio was decreased from 3/2 to 1/1, however, it was significantly reduced by increasing the content of benzoyl peroxide (BPO) and N , N -dimethyl- p -toluidine (DMPT) to 8 and 4 mass% against MMA, respectively. Proliferation and differentiation of MC3T3-E1 cells on PMMA-type cements containing Fe 3 O 4 and TiO 2 with increased BPO and DMPT contents need to be investigated in the future; however, our findings will be useful for designing PMMA cements for the hyperthermic treatment of metastatic bone tumors., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Polymethylmethacrylate (PMMA) bone cement has been widely used as a critical material for fixing prostheses and filling bone defects. The shrinkage of PMMA bone cement was addressed by the additives, however, the uneven integral water absorption and expansion performance as well as the deteriorated mechanical properties of the modified bone cement after immersion in phosphate buffered saline (PBS) and simulation body fluid (SBF) affected the long-term stability after implantation. Calcium phosphate cement (CPC) is a biomaterial with promising applications in orthopedics, whose hydration reaction provides an important driving force for the transfer of water. Besides, the mechanical properties of CPC can be enhanced with the curing process. In this study, CPC was utilized to modify the poly(methyl methacrylate-acrylic acid) [P(MMA-AA)] bone cement. The results demonstrated the successful construction of interconnected CPC water delivery networks in the P(MMA-AA)/CPC composite, the water absorption ratio and expansion ratio of the composite were up to 131.18 ± 9.14% and 168.19 ± 5.44%, respectively. Meanwhile, the transformation of CPC water delivery networks into rigid mechanical support networks as well as the chelation interaction between organic-inorganic enhanced the mechanical properties of the composite after immersion, the compressive strength after immersion reached 62.97 ± 0.97 MPa, which was 27.65% higher than that before immersion. The degradation ratio of the composite was up to 13.76 ± 0.23% after 9 days of immersion, which was 16.4% higher than that of CPC. Furthermore, composites exhibited superior biocompatibility as the release of Ca 2+ . Therefore, P(MMA-AA)/CPC composite serves as a promising medical filling material for clinical use., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Bone cement is commonly utilized in a variety of orthopaedic procedures and contains methylmethacrylate (MMA) monomer. MMA is a colorless, clear, flammable liquid of intense odor. Its vapor concentration in the immediate breathing zone can vary considerably in the operative setting and, in higher concentrations, can become an occupational health hazard. Therefore, reducing MMA vapor is desirable. The aim of this study was to compare the MMA vapor levels emitted during mixing among 5 commercially available cement-mixing systems across 2 operative settings: an operating room (OR) with conventional ventilation (CV) and an OR with laminar airflow (LAF)., Methods: A prospective, in vitro study was conducted at a single hospital in an OR with LAF and in an OR with CV. MMA vapor release during the cement preparation of a SAWBONES femoral canal was measured with use of a calibrated MiniRAE 3000. A total of 5 different vacuum cement-mixing systems were utilized to mix the same cement type according to the manufacturer instructions of each system. MMA vapor concentrations were measured during 5 phases of mixing, and each mixing system was randomly utilized 10 times in each OR., Results: When comparing the MMA concentration levels of each system between the 2 settings, emissions remained generally higher in the CV setting for every system and in nearly every phase. Among the 5 systems analyzed, System #5, the only entirely closed system, had the lowest overall emissions for each of the 5 phases in the CV setting., Conclusions: This study demonstrated that an operative environment with LAF is conducive to clearing the fumes of MMA during mixing as well as limiting the amount of time that residual fumes linger after mixing. Additionally, the entirely closed cement-mixing system was the most effective in minimizing fume levels within the CV setting. Utilizing this closed system, especially in an OR with CV, may reduce exposure to MMA fumes from bone cement, potentially creating a more favorable working environment., Clinical Relevance: This study provides evidence that a closed cement-mixing system utilized under vacuum in both an OR with CV and an OR with LAF is effective in keeping MMA fume levels below those considered harmful by the U.S. Occupational Safety and Health Administration., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H670 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Residual monomer tests using high-performance liquid chromatography and cytotoxicity tests were performed to analyze the effect on the oral mucosa of a self-curing resin for provisional crown production., Methods: A cytotoxicity test was performed to confirm whether leaked residual monomers directly affected oral mucosal cells. The cytotoxicity of the liquid and solid resin polymers was measured using a water-soluble tetrazolium (WST) test and microplate reader., Results: In the WST assay using a microplate reader, 73.4% of the cells survived at a concentration of 0.2% liquid resin polymer. The cytotoxicity of the liquid resin polymer was low at ≤0.2%. For the solid resins, when 100% of the eluate was used from each specimen, the average cell viability was 91.3% for the solid resin polymer and 100% for the hand-mixed self-curing resin, which is higher than the cell viability standard of 70%. The cytotoxicity of the solid resin polymer was low., Conclusion: Because the polymerization process of the self-curing resin may have harmful effects on the oral mucosa during the second and third stages, the solid resin should be manufactured indirectly using a dental model.

Objective: Assessment of post surface conditioners [sulfuric acid (SA), Rose Bengal (RB), and sandblasting (SB)] and different luting cements [methyl methacrylate (MMA)-based cement and composite-based cement] on pushout bond strength (PBS) of poly-ether ether-ketone (PEEK) post bonded to canal dentin. Materials and methods: Endodontic treatment was performed on 120 single-rooted human premolar teeth. The preparation of the post space was performed and 4 mm of gutta-percha was retained in the apical region of the root. One hundred and twenty PEEK posts were fabricated from a PEEK blank utilizing a Computer aided design-Computer aided manufacture (CAD-CAM) system. The PEEK posts were allocated randomly into four groups based on post surface conditioning ( n  = 30). Group A: SA, Group B: RB, Group C: SB, and Group D: No conditioning (NC). Each group was further divided into two subgroups based on the luting cement used for bonding ( n  = 15). Group A1, B1, C1, and D1 specimens were cemented using composite-based resin cement. However, Group A2, B2, C2, and D2 posts were luted with MMA-based resin cement. PBS assessment using a universal testing machine was performed. Failure modes were analyzed under a stereomicroscope. The data relating to the effects of surface treatment and luting types of cement were analyzed using one-way analysis of variance (ANOVA) and Tukey's post hoc test ( p  = 0.05). Results: Coronal section of Group B2: RB+Super-Bond C&B [9.61 ± 0.75 megapascals (MPa)] displayed the highest bond scores of PEEK after root dentin. Whereas it was also discovered that Group D1: NC+Panavia ® V5 (2.05 ± 0.72 MPa) presented the lowest PBS scores. Intergroup comparison analysis revealed that Group A2: SA+Super-Bond C&B and Group B2: RB+Super-Bond C&B displayed no significant difference in their bond scores. Conclusions: RB and SA possess the potential to be used as a PEEK post conditioner. MMA-based cement displayed better performance than composite-based cement.

The high cost of CAD/CAM systems and materials is a severe economic burden. Therefore, repair of CAD/CAM PMMA, selecting appropriate repair materials, and surface modifications are clinically important. This study aims to evaluate the shear bond strength of PMMA repair materials after various surface treatments on CAD/CAM PMMA denture base material. For this purpose, a total of 480 CAD/CAM PMMA denture base test specimens were manufactured. Then all test specimens were divided into 6 groups, and different surface treatments were applied. Group A: sandblasting, Group B: 4% hydro fluoric acid, Group C: tungsten carbide bur, Group D: dichloromethane + methyl methacrylate mixture, Group E: dichloromethane and methyl methacrylate, Group F: no surface treatment. Each group is then divided into 4 different subcategories; repair processes were performed using; heat-cured acrylic resin (n:20), auto-polymerized acrylic resin (n:20), gingiva composite (n:20), and CAD/CAM PMMA tooth material (n:20). After repairs, thermal aging was applied to half of the test specimens in each subcategory. The shear bond strength value was measured with a universal test device. Sandblasting group showed the highest surface roughness value in all test specimens (p < 0.001). Heat-cured acrylic resin with sandblasting exhibited the highest bond strength, while the untreated gingiva composite resin exhibited the lowest value. Thermal aging decreased bond strength in all repair materials (p < 0.001). Among the surface treatment groups, sandblasting with Al 2 O 3 particles exhibited the highest surface roughness value and repair bond strength. The application of organic solvents to the surface increased the surface roughness and repair bond strength. Applying dichloromethane and methyl methacrylate monomer separately is more effective than applying it as a mixture. The ideal bonding among repair materials was obtained with heat-cured acrylic resin., (© 2023. The Author(s), under exclusive licence to The Society of The Nippon Dental University.)

Background: In childhood supracondylar fractures of the humerus, fixation with percutaneous Kirschner wire is the standard treatment. In the case of irreducible-unstable fractures, these can be defined as fractures in which reduction is not well-achieved or in which fixation cannot be achieved with the K-wire. Intraoperative management of these types of fractures may be difficult. Treatment with a methyl methacrylate fixator consisting of K-wire and methyl methacrylate cement, as defined by the senior author of the article, may be a good option for Gartland type IV supracondylar humeral fractures where the fracture is unstable in flexion and extension due to complete periosteal tearing., Materials and Methods: The short-term and mid-term results of 27 patients between the ages of 4-12 with Gartland type IV supracondylar fracture of the humerus treated with methyl methacrylate fixation were reviewed. The patients were scored in terms of function and cosmetic satisfaction., Results: A total of 19 of the 27 patients treated with the methyl methacrylate fixator had full elbow motion function and rated the outcome of the treatment as excellent, which was judged by orthopedic surgeons on the basis of Flynn's criteria. Six patients had nearly full elbow motion and evaluated their recovery outcome as good. Two patients reported nearly full range of motion (ROM) and evaluated the method as moderate in terms of treatment., Discussion: Treatment with the methyl methacrylate fixation method is an inexpensive method that allows early joint mobilization, provides strong biomechanical stability, ensures good outcomes, and should be considered in the treatment of irreducible and unstable supracondylar fractures of the humerus., Competing Interests: None

Copolymerization of styrene with methyl or butylmethacrylates in road petroleum bitumen is studied. The copolymerization of the comonomers selected proceeds in the bituminous medium according to the same laws as in the mass and depends on concentration of the methacrylates. Polymer–bitumen composites, which can be potentially used as structural polymeric materials, have been obtained and studied. [ABSTRACT FROM AUTHOR]

Background: Achieving aesthetic results with forehead augmentation procedures remains challenging. We have developed a method of integrated forehead and temporal augmentation using a three-dimensional (3D) printing-assisted methyl methacrylate implant.Objectives: The study objective was to assess the importance of combined temporal augmentation when performing forehead augmentation.Methods: We identified 34 patients (from 2000 to 2010) who underwent forehead augmentation with a methyl methacrylate implant contoured in situ during surgery and 41 patients (from 2010 to 2016) who underwent integrated forehead and temporal augmentation with a prefabricated methyl methacrylate implant. We conducted a retrospective chart review of patient data including operation time, complications, and instances of revision surgery. Two blinded plastic surgeons scored the aesthetic results of the operations on a 4-point scale (1, poor, to 4, excellent) based on preoperative and posttreatment photographs.Results: The integrated augmentation method resulted in a lower frequency of posttreatment implant removal (one [2%] vs. six [18%]; P < .05), a lower frequency of filler injection for touch up (one [2%] vs. six [18%]; P < .05), and higher mean aesthetic scores (3.7 ± 0.5 vs. 2.2 ± 1.0; P < . 001) compared to the forehead augmentation method. There was no statistically significant difference in surgical complications between the two groups.Conclusions: Integrated forehead and temporal augmentation using a 3D printing-assisted methyl methacrylate implant may be the optimal available procedure, enabling the custom fabrication of contours requested by the patient and providing a rejuvenating and balancing effect on facial appearance.Level Of Evidence3: [ABSTRACT FROM AUTHOR]

The insufficient radiopacity of dental adhesives applied under composite restorations makes the radiographic diagnosis of recurrent caries challenging. Consequently, the misdiagnosis may lead to unnecessary replacement of restorations. The aims of this study were to formulate experimental dental adhesives containing cerium dioxide (CeO2) and investigate the effects of different loadings of CeO2 on their radiopacity and degree of conversion for the first time. CeO2 was characterized by X-ray diffraction analysis, Fourier transforms infrared spectroscopy, and laser diffraction for particle size analysis. Experimental dental adhesives were formulated with CeO2 as the inorganic filler with loadings ranging from 0.36 to 5.76 vol.%. The unfilled adhesive was used as a control. The studied adhesives were evaluated for dispersion of CeO2 in the polymerized samples, degree of conversion, and radiopacity. CeO2 presented a monoclinic crystalline phase, peaks related to Ce-O bonding, and an average particle size of around 16 µm. CeO2 was dispersed in the adhesive, and the addition of these particles increased the adhesives’ radiopacity (p < 0.05). There was a significant decrease in the degree of conversion with CeO2 loadings higher than 1.44 vol.%. However, all materials showed a similar degree of conversion in comparison to commercially available adhesives. CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dental adhesives.

The in-vivo study of bone graft incorporation has traditionally used a segmental diaphyseal bone defect. This model reliably produces a nonunion, but is complicated by graft instability and altered limb loading stresses. The authors discuss the advantages of a defect-in-continuity canine femur model which produces a more consistent union with fewer mechanical complications despite the absence of fixation. This proposed model permits analysis of radiographic, histologic and biomechanical data which are more applicable to the usual clinical setting in which bone graft is required.

Modulating on-demand polymerization is a challenge in synthetic macromolecules. Herein, tailoring polymerization controllability and dispersity during single-electron transfer mediated living radical polymerization (SET-LRP) of methyl methacrylate (MMA) is achieved. Hexaarylbiimidazole (HABI) is employed as a photoswitchable catalyst, allowing reversible control of catalytic activity between an active and inactive state. In the presence of HABI and with the light on (active state), control SET-LRP of MMA follows first-order kinetics, resulting in polymers with a narrow molecular weight distribution. In contrast, polymerization responds to light and reverts to their original uncontrolled state with light off (inactive state). Therefore, repeatable resetting polymerization can be easily performed. The key to photomodulating dispersity is to use an efficient molecular switch to tailor the breadths of dispersity. Besides, the mechanism of HABI-mediated SET-LRP with switchable ability is proposed., (© 2023 Wiley-VCH GmbH.)

Reversible deactivation radical polymerization (RDRP) is a facile and highly efficient technique for the synthesis of well-defined polymer with precise structure. dl-Methionine (Met) as a RDRP control agent is described and assessed for RDRP of styrene (St) and methyl methacrylate (MMA) with AIBN as radical initiator at 75 °C, which enables excellent control of this polymerization. The addition of dl-Methionine significantly decreased the dispersity (Đ) of the polymers for both monomers and first-order linear kinetic plots of polymethyl methacrylate (PMMA) are observed in DMSO. Considering the heat resistance of dl-Methionine, kinetic studies indicate that polymerization develops at a faster rate at higher reaction temperature (100 °C) with the same dl-Methionine content. Well-defined polymethyl methacrylate-block-polystyrene (PMMA-block-PSt) is successfully achieved by the chain extension reaction that demonstrates the high end fidelities of this polymerization approach. The system allows the use of dl-Methionine, a rich source and easily synthesized agent, to mediate RDRP strategy., (© 2023 Wiley-VCH GmbH.)

With global demand for 3D printed medical devices on the rise, the search for safer, inexpensive, and sustainable methods is timely. Herein, we assessed the practicality of the material extrusion process for acrylic denture bases of which successful outcomes can be extended to implant surgical guides, orthodontic splints, impression trays, record bases and obturators for cleft palates or other maxillary defects. Representative materials comprising denture prototypes and test samples were designed and built with in-house polymethylmethacrylate filaments using varying print directions (PDs), layer heights (LHs) and reinforcements (RFs) with short glass fiber. The study undertook a comprehensive evaluation of the materials to determine their flexural, fracture, and thermal properties. Additional analyses for tensile and compressive properties, chemical composition, residual monomer, and surface roughness (Ra) were completed for parts with optimum parameters. Micrographic analysis of the acrylic composites revealed adequate fiber-matrix compatibility and predictably, their mechanical properties improved simultaneously with RFs and decreased LHs. Fiber reinforcement also improved the overall thermal conductivity of the materials. Ra, on the other hand, improved visibly with decreased RFs and LHs and the prototypes were effortlessly polished and characterized with veneering composites to mimic gingival tissues. In terms of chemical stability, the residual methyl methacrylate monomer contents are well below standards threshold for biological reactions. Notably, 5 vol% acrylic composites built with 0.05 mm LH in 0° on z-axis produced optimum properties that are superior to those of conventional acrylic, milled acrylic and 3D printed photopolymers. Finite element modeling successfully replicated the tensile properties of the prototypes. It may well be argued that the material extrusion process is cost-effective; however, the speed of manufacturing could be longer than that of established methods. Although the mean Ra is within an acceptable range, mandatory manual finishing and aesthetic pigmentation are required for long-term intraoral use. At a proof-of-concept level, it is evident that the material extrusion process can be applied to build inexpensive, safe, and robust thermoplastic acrylic devices. The broad outcomes of this novel study are equally worthy of academic reflection, and further translation to the clinic., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The main purpose of this paper is to synthesize a new kind of green and environmental protection emulsion, which can be used as water erosion resistant materials. Here, a non-toxic polymer was prepared by grafting acrylic acid (AA) and methyl methacrylate (MMA) onto the long chains of tara gum (TG) to synthesize a copolymer emulsion (TG-g-P (AA-co-MMA)). The structure, thermal stability, morphology and wettability of the polymer were characterized by conventional methods, and the effects of key synthesis conditions on the performance of the emulsion (viscosity) were optimized. The erosion resistance and compressive strength of polymer-treated loess and laterite soils were evaluated under laboratory conditions. The results showed that the successful grafting of AA and MMA monomers onto TG improved its thermal stability and viscosity. In soil performance tests with low amounts of polymer additive, a 0.3 wt% application of TG-g-P (AA-co-MMA) to loess could resist continuous precipitation for >30 h with an erosion rate of 2.0 %. The compressive strength of the laterite treated with 0.4 % TG-g-P (AA-co-MMA) was 3.7 MPa, which was about three times that of the untreated soil. The results from this study suggest that TG-g-P (AA-co-MMA) emulsions have good potential for soil remediation applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In the present work poly (N-vinyl-2-pyrrolidone-co-methyl methacrylate) copolymers were prepared successfully and cleanly by a one step process via cationic copolymerization of N-vinyl-2-pyrrolidone (NVP) with methyl methacrylate (MMA), in heterogeneous phase using “Maghnite-H+” (Mag-H+) as catalyst in bulk, Maghnite is a montmorillonite sheet silicate clay exchanged with protons to produce Maghnite-H+. Temperature is varied between 20 and 80 °C. The effects of reaction temperature, amount of Mag-H+ on the yield and the intrinsic viscosity (η) were investigated. A typical reaction product of poly (NVP-co- MMA) was analyzed by infra red spectroscopy (FTIR) and 1H-NMR, 13C-NMR spectroscopy as well as by viscosimetry. © 2014 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

The traditional method of producing transparent paper has a great limitation on the kinds of pulp and high requirement for production equipment. The addition of the transparent agent has opened up a new way for improving the existing technology. In this study, the prepolymer of methylmethacrylate was used as a transparent agent for paper impregnation, and the effects of impregnation conditions on paper transparency and physical properties of paper were investigated. The results show that, when the solid content of the transparent agent is 30% and the impregnation time is 10 s in the condition of 40 °C, the transparency of the softwood paper can reach 78%, the 58% is improved, the smoothness is increased significantly, and the elastic modulus is increased to 6. 18 MPa, using methylmethacrylate prepolymer as a transparent agent can improve the opacity of paper significantly. [ABSTRACT FROM AUTHOR]