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Combining polimers with polyphenols such as gallic acid opens up new directions in healthcare system. By encapsulating secondary metabollites within PLGA nanoparticles, we tried to enhance their stability, solubility, and obtain a targeted delivery system. In this study, we synthesized a PLGA-gallic acid sustained release system, using the solvent evaporation method. This approach improved the therapeutic efficacy of gallic acid. The numerical distribution showed that most PLGA-GA nanoparticles have a size of 10 nm. Through the method of solvent evaporation, an incorporation efficiency of 49% was obtained.

In this study, hybrid composite material composed of Poly Lactic Acid (PLA) and Cassia Auriculata (CA) were fabricated and the mechanical properties were evaluated to assess the impact of bio filler loading in the bio polymer (PLA) matrix. In order to fabricate the composite specimens, the CA bio filler was added to the PLA matrix in proportions of 10%, 20%, 30%, 40% and 50% by volume. In line with ASTM specifications, experiments were conducted to establish how the hybrid bio matrix, which was composed of both PLA and CA influenced the composite`s mechanical characteristics. The test results indicated that adding 30 percent CA to PLA enhanced the material`s mechanical, dynamic mechanical analysis, thermogravimetric properties. The composite composition with better properties was considered for further fabrication of a colposcopy fixture, the component was fabricated using additive manufacturing methodology.

Simvastatin, a lipid-lowering drug from the statins group, is used in various dyslipidemias. It appears like a very useful medication to decrease the level of total cholesterol, of the low-density-lipids and triglycerides from blood, but it is well-known that the administration of statins have serious side effects, like muscle pain and weakness that can lead to kidney damage, rash on the skin and inflammation of the joints and of the blood vessels, shortness of breath, inflammation of the liver, dark urine, anemia, memory and sleep disorders, and problems in performing the sexual act. The main aims of this research were to obtain and to characterize a polymer carrier used for the transmembrane transfer of simvastatin. Hepatic arterial variations are common knowledge and it has been studied that these types of arteries have a narrower endoluminal diameter, therefore the patients may be prone to develop atherosclerosis more rapid that the ones with standard hepatic arterial patterns. The samples based on polyurethane structures with and respectively without the active agent were synthesized and characterized by measurements of pH, encapsulation efficacy, cumulative drug release in a simulated body fluid, scanning electron microscopy, Zetasizer measurements, thermal stability, cytotoxicity assay, and non-invasive skin irritation assessment. The results indicate the obtaining of heterogenous polyurethane structures with mean sizes between 80-440 nm and neutral pH, that have a good stability against the agglomeration tendency and a prolonged release rate. The results on structures cytotoxicity and their non-irritative potential are important clues that can be used in further clinical investigations.

This paper presents an analysis of 3D amplitude and functional parameters for worn surfaces of composites with polyamide 6 as matrix and different glass bead concentrations (0%, 2.5%, 5%, 10%, 20%, 30% and 50%wt). The worn surfaces after dry sliding of a steel pin on a disk, for 10 km, at constant velocity (0.5 m/s, 1 m/s and 1.5 m/s) and under an average pressure of 1 MPa. There were done two tests under the same conditions. On each worn track, there were investigated three surfaces of 500 μm x 500 μm with a contact profilometer. The number of points on the scan line was 200 points and the step between lines was 5μm. The following amplitude parameters were measured and calculated for assessed surfaces: the arithmetic mean deviation, Sa, the root mean square deviation, Sq, the maximum height of surface prominence, Sp, the maximum surface depth, Sv, the maximum height, St, the skewness factor, Ssk and the kurtosis, Sku. The discussed functional parameters are the reduced peak height, Spk, the height of the core of the surface, Sk and the depth of the valley zone, Svk. The comparison of their values makes posible to evaluate if the worn surface could function in a new running or the replacement of the component is recommended. Considering that machine components have intermittent operation, these worn surfaces becoming initial surfaces for the following cycle of contact operation. Based on the average values of amplitude and functional parameters, it was found that a relatively good surface quality is preserved for concentrations of 10...30%wt glass beads, for v=0.5...1 m/s (Sa and Sq having similar trend); for lower concentrations and for 50% glass beads, the parameter values increase but without identifying a distinct relationship with the working regime, especially for 2.5 and 5% glass beads.

Virtual reality technologies are important auxiliary tools in the process of learning and acquiring the manual skills necessary for clinical maneuvers in dental prosthodontics. This study shows the particularities in the use of the virtual simulation system designed for dental prosthodontics, compared to the classically preparations performed on resin models. The interactively simulation systems reproduce real clinical situations in which students practice specific dental prosthetics maneuvers. Resin models do not reproduce the accuracy of the dental structures at the time of the preparation. The advantages of using virtual technology are efficient clinical training, allowing for repeatability, self-assessment of procedures and the acquisition of manual skills. In this way, the advantages conferred by virtual simulators are superior to those resulting from the use of resin models in the acquirement of manual skills.

Among the properties of materials for direct coronal restorations, water absorption is particularly important, influencing the mechanical properties, color and adhesion of the restorations made.The aim of this study was to compare the water absorption of six dental restorative materials, two composite, two compomers and two glass ionomers. Water absorption was determined on disk samples. 30 discs were prepared, 5 of each studied material, with a diameter of 15 mm and a thickness of 1 mm. The water absorption test was carried out based on the ISO 4049 specification. The composites and compomers showed a water absorption within the standard limits (40 µg/mm3). Glass ionomers show high water absorption, therefore to be used as coronal restorative materials they need to be coated with a protective varnish.

Recent progress in Material Extrusion-based Additive Manufacturing (MEX) has introduced active foaming agents in filaments composition, thus allowing for the tuning, by various process parameters, the hardness and the mechanical behavior of 3D-printed parts. In case of thermoplastic polyurethane (TPU) filaments, these advances significantly broaden the range of applications, particularly in the domains of comfort and orthotics (wrist-hand orthoses, insoles), offering the dual benefits of design flexibility inherent in MEX and the comfort of lightweight and customizable structures. However, the field is still in its early stages, with only a limited number of research efforts dedicated to characterizing these novel materials. In this context, this study is focused on determining the influence of printing temperature (190°C, 220°C, 240°C), infill density (25%, 35%, 45%) and infill pattern (honeycomb, gyroid) over the hardness of cylindrical specimens made of Colorfabb varioShore TPU. A comprehensive methodology of calibration is also presented as mandatory for obtaining good quality and accurate products by establishing correlations between flow rate and printing temperatures. The findings showed that the printing temperature is the most relevant factor impacting the hardness of varioShore TPU prints. At a printing temperature of 190°C, which corresponds to less foamed prints, the honeycomb infill yielded higher hardness compared to the gyroid infill, but the difference was not significant. Also, at 220°C and 240°C, the mean values of hardness remain relatively consistent, regardless of infill density and pattern.

This article examines the impact of surface treatment of glass fibers on the strength of a composite material with an unsaturated polyester polymer matrix reinforced with glass fibers. The strength tests conducted include tensile, bending, and impact strength tests, as well as weight loss measurements. The research was conducted in two stages: in the first stage, the time was kept constant while the fibers were treated with varying concentrations of an alkaline NaOH solution; in the second stage, the concentration was fixed and the variable parameter was the treatment time. The results of the study indicate that surface treatment of glass fibers significantly improves their adhesion to the matrix materials, resulting in improved strength test results for the composite samples. The impact resistance, bending resistance, and tensile strength values all increased compared to the reference samples. However, certain changes in the individual parameters of fiber processing led to a slight decrease in tensile strength when it fell below the reference values. Additionally, it was observed that as the concentration of the solution and treatment time increased, the weight of the fibers decreased.

Last years research in polymers registered an increase of interest regarding polymer mixtures aiming to obtain materials with properties of the mixed polymers. In this respect many studies are pointing the mixtures between a thermoset polymer and a thermoplastic polymer. It is known the fact that thermoplastic polymers are much more malleable than the thermoset ones and the goal is to obtain a mixture with the general properties of the thermoset polymer and with a machining ability proper to the thermoset polymer. The vitrimers are this type of polymers and, some of them, can be obtained by mixing polymers form the two categories. This study is about using solutions of two thermoset polymers to modify the basic properties of three epoxy resins. The results show that the presence of PMMA, respectively, PLA inside the epoxy resin matrix determines changes of the mechanical properties of the formed materials. Without analysing the adhesive properties of new materials is hard to decide about their value from the composites applications point of view.

Since the invention of the first UAV’s, different industries realized it’s capabilities and potential uses. Drones and UAV’s are part of our everyday life and their development has seen an unprecedented speed due to their multiple applications, from scientific research to military applications. When we talk about UAV’s we also talk about composite materials. Today’s drones and UAV’s are using almost exclusively carbon fiber, glass fiber and 3D printed materials. This paper presents the development and testing of fiber carbon materials along with a future concept of an UAV. In the end of this paperthe results of testing the materials are presented.