Methacrylate Type Research Articles

Comparison of cation and anion-mediated resolution enhancement of bioprinted hydrogels for membranous tissue fabrication.

Fabrication of engineered thin membranous tissues (TMTs) presents a significant challenge to researchers, as these structures are small in scale, but present complex anatomies containing multiple stratified cell layers. While numerous methodologies exist to fabricate such tissues, many are limited by poor mechanical properties, need for post-fabrication, or lack of cytocompatibility. Extrusion bioprinting can address these issues, but lacks the resolution necessary to generate biomimetic, microscale TMT structures. Therefore, our goal was to develop a strategy that enhances bioprinting resolution below its traditional limit of 150 μm and delivers a viable cell population. We have generated a system to effectively shrink printed gels via electrostatic interactions between anionic and cationic polymers. Base hydrogels are composed of gelatin methacrylate type A (cationic), or B (anionic) treated with anionic alginate, and cationic poly-L-lysine, respectively. Through a complex coacervation-like mechanism, the charges attract, causing compaction of the base GelMA network, leading to reduced sample dimensions. In this work, we evaluate the role of both base hydrogel and shrinking polymer charge on effective print resolution and cell viability. The alginate anion-mediated system demonstrated the ability to reach bioprinting resolutions of 70 μm, while maintaining a viable cell population. To our knowledge, this is the first study that has produced such significant enhancement in extrusion bioprinting capabilities, while also remaining cytocompatible.

Preparation and efficacy of antibacterial methacrylate monomer-based polymethyl methacrylate bone cement containing N-halamine compounds.

Our objective in this study was to prepare a novel type of polymethyl methacrylate (PMMA) bone cement, analyze its material properties, and evaluate its safety and antibacterial efficacy. A halamine compound methacrylate antibacterial PMMA bone cement containing an N-Cl bond structure was formulated, and its material characterization was determined with Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR. The antibacterial properties of the material were studied using contact bacteriostasis and releasing-type bacteriostasis experiments. Finally, in vitro and in vivo biocompatibility experiments were performed to analyze the toxic effects of the material on mice and embryonic osteoblast precursor cells (MC3T3-E1). Incorporation of the antibacterial methacrylate monomer with the N-halamine compound in the new antibacterial PMMA bone cement significantly increased its contact and releasing-type bacteriostatic performance against Staphylococcus aureus. Notably, at 20% and 25% additions of N-halamine compound, the contact and releasing-type bacteriostasis rates of bone cement samples reached 100% (p < 0.001). Furthermore, the new antibacterial bone cement containing 5%, 10%, and 15% N-halamine compounds showed good biocompatibility in vitro and in vivo. In this study, we found that the novel antibacterial PMMA bone cement with N-halamine compound methacrylate demonstrated good contact and releasing-type bacteriostatic properties against S. aureus. In particular, bone cement containing a 15% N-halamine monomer exhibited strong antibacterial properties and good in vitro and in vivo biocompatibility.

Comparison of Bond Strength Between Two Resin Cement Types and Additive Manufacturing or Cast Cobalt-Chromium Alloys.

To compare the bond strength of two types of resin cement to that of additive manufacturing (AM) or cast cobalt-chromium (Co-Cr) alloys. Two types of resin luting cement, composite resin and methyl methacrylate (MMA), were bonded to AM or cast Co-Cr alloys, and shear bond tests were performed after seven days of storage in distilled water at 37°C. Co-Cr alloy adhesive elements AM to the enamel surface of the labial aspect of a bovine mandibular central incisor crown were bonded with two types of resin luting cement and subjected to 1,000 cycles of storage in water for one day and 28 days or thermal cycling, followed by shear bonding tests. Residual cement on the metal and enamel surfaces after the bonding tests was evaluated using an optical microscope. The normality of the results was evaluated using statistical software Statcel4, analysis of variance, or Kruskal-Wallis test, depending on normality, and multiple comparison tests were performed using the Tukey-Kramer or Steel-Dwass tests. After one day, the shear bond strength (SBS) was 25.9 MPa for Panavia V5 (PV; Kuraray Noritake Dental Corporation, Niigata, Japan) and 23.5 MPa for Super-Bond (SB; Sun Medical Corporation, Shiga, Japan), with no significant difference between the two cement types (P > 0.05). After 28 days, the SBS decreased to 4.1 MPa for PV and 6.7 MPa for SB, showing a significant difference between the two cements (P < 0.05). Following 1,000 thermal cycles, the SBS was 2.0 MPa for PV and 5.6 MPa for SB, with SB exhibiting a significantly higher value (P < 0.05). The adhesive strength was significantly lower after 28 days of storage and thermal cycling compared to after one day of storage (P < 0.05). The Co-Cr alloy exhibited more residual cement on the enamel surface due to interfacial fracture with the resin cement. The Co-Cr alloy showed more residual cement on the enamel surface due to interfacial fracture with the resin cement. MMA-based resin cement showed optimal bond strength and may be suitable for clinical use in computer-aided design (CAD)/computer-aided manufacturing (CAM) orthodontic appliances.

Adsorption of oxytetracycline in hyporheic zone sediments mediated by microplastics: Experimental revelations and mechanistic insights

Microplastics (MPs), serving as carriers, possess a mediating effect on altering antibiotics (ATs) migration, yet this novel effect has not received due attention in the vulnerable hyporheic zones where surface water and groundwater converge. This study collected sediment layers from the typical hyporheic zone of the Weihe River, focusing on oxytetracycline (OTC) detected therein, and employed three types of MPs (polyethylene (PE), polypropylene (PP), and polymethyl methacrylate (PMMA) to establish various mediated adsorption systems. Through batch equilibrium adsorption experiments, morphological and spectroscopic characterizations combined with the impact of external environmental factors, the changes in OTC adsorption characteristics and the interactions before and after MPs mediation were systematically examined. The results indicate that MPs-mediated adsorption led to the formation of a rough, porous amorphous structure on the sediment surface, with potential internal hydrogen bonds. This exhibited an additional micropore diffusion step that delayed the adsorption kinetics equilibrium time, increased the isothermal maximum adsorption capacity along with desorption hysteresis effects, shifted thermodynamic enthalpy from physically dominated to semi-chemical adsorption participation, and resulted in an increased tendency towards disorder in entropy. The pH, ionic strength, and aging of MPs all affect the charge balance within the adsorption system, while MPs, OTC, and sediments can interact through the negative-charge-assisted hydrogen bond ((−)CAHB). The mediating effect of MPs stems from their role as receptors, facilitating the formation of (−)CAHB and thus crosslinking an amorphous structure available for OTC micropore filling. Compared to PE and PP, PMMA provides receptors through an additional free radical pathway, hence possessing a stronger mediating effect. These findings contribute to reevaluating the environmental fate of ATs and MPs from a new perspective, offering theoretical references for risk assessment and management of emerging pollutants.

Enhanced Vascular-like Network Formation of Encapsulated HUVECs and ADSCs Coculture in Growth Factors Conjugated GelMA Hydrogels.

Tissue engineering primarily aimed to alleviate the insufficiency of organ donations worldwide. Nonetheless, the survival of the engineered tissue is often compromised due to the complexity of the natural organ architectures, especially the vascular system inside the organ, which allows food-waste transfer. Thus, vascularization within the engineered tissue is of paramount importance. A critical aspect of this endeavor is the ability to replicate the intricacies of the extracellular matrix and promote the formation of functional vascular networks within engineered constructs. In this study, human adipose-derived stem cells (hADSCs) and human umbilical vein endothelial cells (HUVECs) were cocultured in different types of gelatin methacrylate (GelMA). In brief, pro-angiogenic signaling growth factors (GFs), vascular endothelial growth factor (VEGF165) and basic fibroblast growth factor (bFGF), were conjugated onto GelMA via an EDC/NHS coupling reaction. The GelMA hydrogels conjugated with VEGF165 (GelMA@VEGF165) and bFGF (GelMA@bFGF) showed marginal changes in the chemical and physical characteristics of the GelMA hydrogels. Moreover, the conjugation of these growth factors demonstrated improved cell viability and cell proliferation within the hydrogel construct. Additionally, vascular-like network formation was observed predominantly on GelMA@GrowthFactor (GelMA@GF) hydrogels, particularly on GelMA@bFGF. This study suggests that growth factor-conjugated GelMA hydrogels would be a promising biomaterial for 3D vascular tissue engineering.

Both nanoplastic and iron mineral types determine their heteroaggregation: Aggregation kinetics and interface process

Nanoplastics (NPs) inevitably interact with iron minerals (IMs) after being released into aquatic environments, changing their transport and fate. In this study, batch heteroaggregation kinetics of four types of NPs, i.e., polymethyl methacrylate (PMMA), polystyrene (PS-Bare), amino-polystyrene (PS-NH2), and carboxyl-polystyrene (PS-COOH), with two different IMs (hematite and magnetite) were conducted. We found that the heteroaggregation of NPs and IMs and the associated interfacial interaction mechanisms are both NPs-dependent and IMs-dependent. Specifically, the NPs had stronger heteroaggregation with hematite than magnetite; the heteroaggregation order of two IMs with NPs was PMMA > PS-NH2 > PS-Bare > PS-COOH. Moreover, hydrogen bond, complexation, hydrophobic, cation-π, and electrostatic interaction were involved in the interfacial reaction between NPs and hematite, and electrons were transferred from the NPs to the hematite, causing the reduction of Fe3+ into Fe2+. Furthermore, we first revealed that both pre-homoaggregation of NPs and IMs could affect their subsequent heteroaggregation, and the homoaggregates of IMs could be interrupted by PMMA or PS-COOH NPs introduction. Therefore, the emerging NPs pollution is likely to generate an ecological effect in terms of elemental cycles such as iron cycle. This work provides new insights into assessing the environmental transfer and ecological effects of NPs in aquatic environments.

A Versatile and Efficient Method to Isolate DNA-Polymer Conjugates.

We present a facile and adaptable method to purify and isolate DNA-polymer conjugates from different uncharged homo, random, or block copolymer families. Anion exchange chromatography is used to separate the reaction solution and retrieve the excess unreacted polymer and oligonucleotide. The stationary phase has a high efficiency (25 nmol of DNA per run), facilitating the purification of large batches without compromising the peak shape and resolution. To demonstrate the versatility of this method, different types of polymers, including acrylates, methacrylates, and acrylamides containing hydrophilic and hydrophobic blocks, were purified with high yields. Additionally, DNA-polymer conjugates with various DNA block lengths were also successfully purified, further highlighting the broad applicability of this method.

The Presence of Microplastics in the Gills and Gastrointestinal Tract of Mackerel (Rastrelliger Kanagurta Cuvier, 1816) from Jakarta Bay, Indonesia.

This study examined the characteristics of microplastics (MPs) in the gills and gastrointestinal tract (GIT) of mackerel (Rastrelliger kanagurta) captured in Jakarta Bay, Indonesia. All 120 fish contained MPs, with fragment > fiber > film being the most prevalent types, in that order. The total abundances of fragments, fibers, and films in the gills were as follows: 4.8 ± 1.6, 1.0 ± 0.7, and 0.3 ± 0.3, respectively. The total abundances of fragments, fibers, and films in the GIT were 5.9 ± 2.3, 1.3 ± 0.8, and 0.4 ± 0.4, respectively. Statistical analysis showed that the abundance of fragments, fibers and films in both the gills and GIT of mackerel did not differ significantly between sampling locations. In the gills and GIT, MPs with sizes less than 0.1mm and MPs that were black in color were most prevalent. Fourier transform infrared (FTIR) spectroscopy tests on MPs from the tissues of mackerel showed that there were 8 different types of MP polymers, namely, latex, nylon, polymethyl methacrylate (PMMA), cellulose acetate (CA), polyurethane (PU), polycarbonate (PC), polystyrene (PS), and polytetrafluoroethylene (PTFE). Latex and polycarbonate were detected in fish samples from Jakarta Bay.

Macrocyclic Allylic Sulfone as a Universal Comonomer in Organocatalyzed Photocontrolled Radical Copolymerization with Vinyl Monomers

Radical copolymerization of vinyl monomers and cyclic monomers is a versatile approach to degradable vinyl plastics. Despite recent advances, a class of “universal” cyclic monomers that possess broad reactivities with various types of vinyl monomers remains elusive. Herein, we report a general method for the organocatalyzed photocontrolled radical ring-opening cascade copolymerization (rROCCP) of macrocyclic allylic sulfone and various types of vinyl monomers, including acrylates, acrylamides, styrene, and methacrylate. Catalyzed by Eosin Y under visible light irradiation, the copolymerization of macrocyclic allylic sulfone and acrylic monomers displayed near unity comonomer reactivity ratios by fitting the copolymer composition to the Beckingham–Sanoya–Lynd integrated model. Macrocyclic allylic sulfone was also successfully copolymerized with styrene (r1 = 3.02 and rSt = 0.35) or methyl methacrylate (r1 = 0.18 and rMMA = 5.81) to generate degradable polystyrene and poly(methyl methacrylate). These degradable vinyl copolymers exhibited tunable thermal properties correlated with the incorporation of the degradable main-chain diester motif. The unprecedented reactivities that macrocyclic allylic sulfone demonstrated in the organocatalyzed photocontrolled rROCCP provide a general approach to the wide range of degradable vinyl plastics with various structures and functions.

Improvement of mechanical properties of recycled PET by reactive toughening and post-crystallization

Noticeable increase in impact strength of recycled PET (RPET) was achieved using ethylene-butyl acrylate-glycidyl methacrylate (EBA-GMA) type reactive terpolymer (PTW). The decrease in stiffness and heat resistance due to reactive toughening was successfully compensated by thermal annealing. Based on the results, strong correlation can be shown between crystallinity and impact strength: increasing crystallinity results in reduced impact resistance at PTW contents higher than 5 m/m%, yet a 6-time increase compared to 100 % crystallized RPET was reached with 15 m/m% PTW content. Regarding heat resistance and stiffness, crystallinity appears to be the key parameter: above a critical value of 10 % crystallinity a sharp improvement of the properties can be noticed. Based on the results, properly choosing the elastomer ratio and post-crystallization conditions, post-consumer PET can be suitable for durable engineering applications as well.

Water boosts reactive toughening of PET

During melt-processing, the molecular weight of poly(ethylene terephthalate) PET, being prone to hydrolytic degradation, decreases proportionally with its initial moisture content. Therefore, to avoid undesired deterioration of the physical and mechanical properties, PET granules or recyclates are generally dried (the residual moisture must be generally lower than 500 ppm) just prior to melt-processing. In this research, in contrast to the general practice, PET granules with increasing moisture content in the range of 30-3520 ppm, as conditioned in a climate chamber, were melt blended with a constant amount (13%) of ethylene-butyl acrylate-glycidyl methacrylate (EBA-GMA) type reactive terpolymer by twin screw extrusion. It was found that moisture boosts the reactive toughening process, and consequently, the notched Izod impact strength increases by up to 600%. Notched impact strength higher than 50 kJ/m2 was reached only by using PET with optimal (1710 ppm) moisture level instead of fully dried granules, as starting material. It is also noteworthy that the tensile strength and stiffness of the blends showed little variation over the examined moisture content range. Scanning electron microscopic analyses show that the size of the dispersed phase decreases continuously with the increasing initial moisture content of PET, which is explained by the increasingly effective interfacial compatibilisation with the terpolymer. Compatibilisation reactions are accelerated by the low-molecular-weight PET chains of increased reactivity that are formed in situ in the presence of moisture during melt-processing. The observed phenomenon can be advantageously utilized for upgrading recycling technology.

Seasonal and spatial distribution of microplastics in sediments by FTIR imaging throughout a continuum lake - lagoon- beach from the Tunisian coast

Plastics pollution in marine environment has become an issue of increasing scientific concern. This work aims to study the temporal and spatial distribution of plastics in sediments from three different Tunisian ecosystems; Rimel Beach, Bizerta lagoon and Ichkeul lake. Sediment sampling was conducted in surface (2 cm) and depth (15 cm) during spring, summer and winter. Plastics debris were separated by size fractions: macro (>5 mm), meso (1–5 mm) and microplastics (<1 mm) to optimize the time necessary for their characterisation. Macroplastics and mesoplastics were identified using an IR Attenuated total reflectance (ATR) and microplastics with Imaging Fourier transform infrared spectroscopy (FTIR) spectroscopy after an optimized extraction protocol. Results indicate that, the lowest contamination degree with macroplastics was recorded in Ichkeul lake, 2 macro debris/m2 (marine protected area, national parc of Ichkeul). Mesoparticles were only detected in lagoon of Bizerte in large quantities (4900 item/kg of sediment in surface and 680 item/kg of sediment in depth) and were identified principally as paint products. For microplastics, the repartition was quite homogeneous between the three sites with an average abundance was 130.55 ± 65.61 items/kg for all seasons. The variations of microplastics abundances on the three sites could not be clearly related to the seasons. Whereas the polymer characterisation in the surface and depth sediments of the three studied areas were principally due to eight types of polymers (PVC, PET, PP, PE PS, Polyamide (PA) and polymeric methyl methacrylate (PMMA)) as reported in many other studies, surprisingly all MPs recovered in the study were smaller than 300 μm, >70 % being fragments. This study brings new results as regards to the state of plastic contamination in Tunisian coast and shows the importance of investigating different ecosystems in such studies.

Effect of crosslinker on the wettability and mechanical properties of hydrophobic coatings deposited via atmospheric pressure plasma

AbstractHydrophobic coatings based on dodecyl acrylate (DOCA) and perfluorodecyl acrylate (PFDA) have been generated via “postdischarge” atmospheric pressure plasma deposition. These coatings exhibit a water contact angle (WCA) of around 125° but are accompanied by poor mechanical strength. To improve this property, two different types of chemical crosslinkers, that is, hexanediol methacrylate (HDMA) and hexanediol diacrylate (HDA), are incorporated into the precursor mixture. After plasma polymerization, both coatings with crosslinkers admixture show different wettability behavior. The addition of HDMA reduces the WCA while increasing the mechanical strength, while the addition of HDA retains the initial WCA magnitude while also increasing the mechanical strength. These changes are related to variations of the surface free energy (SFE) and topography of the plasma coatings.

A Novel Aminomethacrylate-Based Copolymer for Solubility Enhancement-From Radical Polymer Synthesis to Manufacture and Characterization of Amorphous Solid Dispersions.

The present study covers the synthesis, purification and evaluation of a novel aminomethacrylate-based copolymer in terms of its suitability for improving the solubility and in vitro release of poorly water-soluble drug compounds. The new copolymer was synthesized by solvent polymerization with radical initiation and by use of a chain transfer agent. Based on its composition, it can be considered as a modified type of dimethylaminoethyl methacrylate-butyl methacrylate-methyl methacrylate “EUDRAGIT® E PO” (ModE). ModE was specifically developed to provide a copolymer with processing and application properties that exceed those of commercially available (co-)polymers in solubility enhancement technologies where possible. By varying the concentration of the chain transfer agent in the radical polymerization process, the molecular weight of ModE was varied in a range of 173–305 kDa. To evaluate the solubility-enhancing properties of ModE, a series of drug-loaded extrudates were prepared by hot melt extrusion using the novel—as well as several commercially available—(co-)polymers. These extrudates were then subjected to comparative tests for amorphousness, solubility-enhancing properties, storage stability, and drug release. Celecoxib, efavirenz, and fenofibrate were used as model drugs in all experiments. Of all the (co-)polymers included in the study, ModE with a molecular weight of 173 kDa showed the best performance in terms of desired properties and was shown to be particularly suitable for preparing amorphous solid dispersions (ASDs) of the three model drugs, which in a first set of dissolution experiments showed better release behavior under pH conditions of the fasting stomach than higher molecular weight ModE types, as well as a variety of commercially available (co-)polymers. Therefore, the results demonstrate the successful synthesis of a new copolymer, which in future studies will be investigated in more detail for universal application in the field of solubility enhancement.

Structural design and characterization of tricycloalkyl-containing methacrylate with methyl methacrylate copolymers

Three types of tricycloalkyl-containing methacrylate with methyl methacrylate copolymers, poly(adamantyl methacrylate-co-methyl methacrylate) [P(ADMA-co-MMA)], poly(tricyclodecyl methacrylate-co-methyl methacrylate) [P(TCDMA-co-MMA)] and poly(adamantyl methacrylate-co-tricyclodecyl methacrylate-co-methyl methacrylate) [P(ADMA-co-TCDMA-co-MMA)] were synthesized via the free-radical polymerization method. The effects of structural design on the thermal, mechanical, dielectric and optical properties of the synthesized copolymers were investigated. The results showed that the tricycloalkyl-containing methacrylate copolymers increased the thermal stability, mechanical strength and transparency in the UV–visible region as compared with PMMA. Additionally, a lower water absorption and dielectric constant were obtained. These results demonstrated that tricycloalkyl-containing methacrylate copolymers are promising candidates for use as high value-added optical plastics in microelectronics and optoelectronics applications.

Application of low-grade recyclate to enhance reactive toughening of poly(ethylene terephthalate)

This paper presents a new recognition in reactive toughening of poly(ethylene terephthalate) (PET), namely the major effect of the molecular weight of PET on the evolution of the compatibilization and crosslinking reactions with ethylene‑butyl acrylate-glycidyl methacrylate (EBA-GMA) type reactive terpolymer, and thus indirectly on its toughening efficiency. It was found that the use of highly degraded recycled PET (rPET) grades, due to the available larger number of reactive functional end groups and increased mobility of the decreased-molecular-weight chains, multiplies the impact strength of the product compared to that of original PET (oPET) with identical EBA-GMA contents. The evinced noticeable difference between the toughening behaviour of rPET and oPET is explained by morphological and interfacial factors and connected to differences in rheological behaviour as well. The reactive oligomeric rPET macromolecules form a Toughening Enhancer Interphase (TEI) around the dispersed particles. Based on systematic analyses, conclusions were drawn regarding the quality, i.e. optimal intrinsic viscosity (IV) range, and quantity of rPET to be used to obtain high-impact-strength PET blends (notched Izod impact strength higher than 40 kJ/m2) with optimised mechanical properties, being suitable even for injection moulding applications, at significantly lower terpolymer contents (10.0–12.5 wt%) than expected. Besides, the proposed new way of utilisation of PET recyclates, especially the unmarketable highly degraded fractions, is believed to give a new driving force in PET recycling.

Optimum design of the surface plasmon resonance sensor based on polymethyl methacrylate fiber

A novel type of polymethyl methacrylate (PMMA) fiber refractive index sensor based on surface plasmon resonance (SPR) is proposed in this work, which is applied to measure the refractive index of liquid. The performance is investigated by the SPR theory and the structural properties of the side-polished D-type fiber. In order to obtain the optimized parameters of SPR sensor, the effects of metal film material, the metal film thickness and the length of the sensing zone on spectral characteristics of the sensor are studied. The fiber SPR sensor is manufactured and applied to the preparation experiment. The change of refractive index of glycerol solution is detected and analyzed at a constant temperature of 20 ​°C. Experimental results indicate that the proposed fiber SPR sensor exhibits refractive index sensitivity up to 3328.1 nm/RIU in the range of 1.334–1.388, which can be utilized as the alternative material for bio-sensing studies.

To Evaluate the Effect of Water Temperature and Duration of Immersion on the Marginal Accuracy and Microhardness of Provisional Restoration: An In Vitro Study

Abstract Introduction Provisional restoration is a critical component of fixed prosthodontics treatment, which must satisfy many inter-relative factors such as biological, mechanical, and esthetic. These restorations should have accurate marginal adaptation and optimum strength to maintain functional demands. The present “in vitro” study was conducted to evaluate the effect of water temperature and duration of immersion, on the marginal adaptation and microhardness of four different commercially available provisional restorative materials. Materials and Methods The 240 specimens were then seated on the stainless-steel die which simulated the prepared tooth, and evaluated for the marginal gap for four different provisional restorative materials and divided into four different groups A, B, C, and D. Each group was further divided into six subgroups according to temperature of water and time of immersion. In each group the samples were immersed in water at 20, 30, and 40 degrees, respectively for 5 and 10-minutes duration. Four different temporary restorative materials for crown fabrication were loaded each time to make temporary crowns. Results Each sample was placed under travelling stereoscopic microscope (20× magnification) and photographed. Results for each surface were obtained, and the average of three surfaces was calculated. Knoop hardness was measured using a microhardness tester. The study was subjected to statistical analysis, to know the statistical significance, of the effect of difference in time and temperature changes at the time of final polymerization on surface microhardness and marginal integrity of four different provisional restorative materials. Discussion The mean marginal discrepancies of bis-GMA (group B) at 20, 30, and 40°C for 5 and 10 minutes in water were smaller than the results of other groups. Microhardness evaluation showed that the poly ethyl methacrylate (PEMA) type resin exhibited significantly lower microhardness than the bis-acryl resin composites (Protemp 4 and Systemp.c&amp;b) at both time and temperature intervals. Conclusion The bis-acryl composites material has the least marginal discrepancy in comparison with PEMA and polymethyl methacrylate (PMMA). The bis-acryl composites materials exhibit superior surface microhardness followed by PEMA and PMMA.

In situ bioadhesive film-forming system for topical delivery of mometasone furoate: Characterization and biopharmaceutical properties

In situ film-forming systems (FFS) are attractive drug delivery systems employed for the topical administration of drugs. They are transparent and have high substantivity and improved cosmetic attributes. Two types of polymeric materials, methyl methacrylate and cellulosic derivates, were employed for the topical delivery of mometasone furoate. A previous screening of polymers and plasticizers was performed to select the best candidates based on cosmetic characteristics. Water vapor permeability determines the occlusive profile, and it has been observed that it depends on the polymer type. The rheological, bioadhesion, and mechanical properties of the films revealed that the best candidates were Eudragit S100 and HPMC films. These polymers also exhibited the slowest drug release and limited permeation across the skin, with no alteration in the microstructure of the skin layers after diffusion experiments. Both FFS were adequate to improve patient compliance with treatment due to the cosmetic attractiveness and a potential reduction in administration frequency. They also potentially allow for administration to high-friction areas and the face.

Variable thermal conductivity and viscosity effects on non-Newtonian fluids flow through a vertical porous plate under Soret-Dufour influence

The purpose of this paper is to consider heat and mass transfer processes on two non-Newtonian fluids (Walters-B viscoelastic and Casson fluid) situated in a hot environment. This study considered concentrated fruit juice and tomato sauce as the type of Casson fluid and polymethyl methacrylate, chromatography, and ceramic processing as the type of Walters-B viscoelastic fluids. The model is governed by systems of partial differential equations. These equations were simplified with the help of appropriate similarity variables to obtain nonlinear couple fourth-order ordinary differential equations. The transformed equations were solved numerically using the spectral homotopy analysis method (SHAM). SHAM is rooted in the homotopy analysis method (HAM) and the Chebyshev spectral collocation method. SHAM is efficient and converges faster than HAM. This paper is unique because it explored variable viscosity and thermal conductivity in the presence of flow parameters such as Soret, Dufour, radiation, viscous dissipation, magnetic field, and so on. The applied magnetic field serves as an opposition to the flow and thereby slows down the motion of an electrically conducting fluid. The influence of pertinent flow parameters is extensively discussed and presented graphically. The permeability parameter is noticed to decrease the velocity profile and increase the temperature profile. The present results were found to be in good agreement with existing works in literature.