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Growing demands from industry for the use of eco-friendly lubricants led research towards finding environmentally friendly products with superior lubricating characteristics. Vegetable oils and synthetic ester oils are competitive base oils used to obtain lubricants with good physico-chemical, rheological and tribotechnical properties, biodegradable lubricants without negative environmental impacts. In this study we aimed the synthesis and characterization of bioesters with lubricant properties, using as acid component the soybean oil fatty acids in conjunction with the following hydroxyl compounds n-buthanol (P1) and 1,2-propilenglycole (P2), respectively. These complex esters were synthesized in a microwave reactor in a single stage in the presence of the catalyst at the reflux temperature. Characterization was carried out in the respective of structural point of view and as a lubricant.

This paper aims to synthesize the main categories of biomaterials (bone substitutes, collagen membranes) used in the reconstruction of oral bone defects and alveolar augmentation by guided bone regeneration technique. The review of literature data shows that guided bone regeneration technique offers reliable and predictable results in the implant-prosthetic treatments.

Resin-based pit and fissure sealant materials are heterogeneous materials with two principal components: the resin matrix and the filler particles. The shear bond strength test holds great importance for providing insight into the adhesion of these materials and, also, it is a screening mechanism for predicting clinical performance. The purposes of the present study are to investigate the structure of surface and the shear bond strength for two commercial pit and fissure sealants, Fissurit (VOCO) and Pit &Fissure (DMP) sealer. Seal Fissurit had the highest shear strength, and the difference was statistically significant between two tested materials.

In lumbar disc herniation a possible functional problem in the ambulation is the Foot-drop syndrome caused by radicular nerve pinching. This causes a dramatic loss in gait cycle efficiency. In the rehabilitation process patients may benefit from wearing a foot orthosis that prevents them from falling and secondary injuries. Evidence in the literature suggests the important correlation between the optimal match of the forces produced during human gait and the rigidity of the constructive materials. The inherent rigidity of the materials plays an important role in determining its biomechanical functions. The paper proposes an experimental and numerical characterization of 3D printed ABS and PLA specimens using a universal traction-compression testing machine and a finite element method numerical simulation.

Using antibiotic impregnated cement is an important mean to treat and prevent periprostetic joint infections. This complication requires for treatment important financial and technical resources. Adding antibiotics to orthopaedic cement may alter its mechanical properties with possible reduced time of prosthesis survival rate. This study analyze the mechanical properties of cement mixed with antibiotics in the operation room, which helps reducing costs and permit a more specific antibiotic local therapy. All tested antibiotics used in this study does not change the mechanical behavior of the orthopaedic cement when mixed in therapeutic doses, all alterations seems to be at a level below clinical significance. Mixing antibiotics in Orthopedic cement leads to minor decrease of the mechanical properties for cefazolin, cefuroxime, ceftazidime, meropenem and vancomycin and a mechanical significant decrease for gentamicin and clindamycin.

In the paper, a new Euler-Bernoulli theory is presented, in which the bars eigenpulsations with rectangular section increase with the ratio between the bar width and thickness. This theory is experimentally verified for composite bars made of Dammar reinforced with cotton and flax plus one or two layers of fiber glass fabric. For the considered bars, we have experimentally determined the eigenfrequencies and the damping factor values. We have experimentally determined the Young modulus and breaking strength for the used resin and the obtained composites.

The influence of aluminosilicates on the structure and drug release profiles of polyvinyl alcohol (PVA) – halloysite (HNT) hydrogels containing acetylsalicylic acid (ASA) as a model drug was monitored. The hydrogels were synthesized using a three cycle freeze – thawing procedure and were characterized by FTIR, XRD and SEM. The swelling degree and cytotoxicity were also determined. All hydrogels properties were influenced by HNT concentration from the polymer matrix. The release of ASA, from PVA – HNT hydrogels was monitored in the gastrointestinal tract conditions.

Verteporfirin is the active substance of the medicine Visudyne (the basic form porphyrin of the medicine) approved and in use for ophthalmic diseases and tumor types. Because the informations from literature about degraded of this porphyrins are greatly reduced, we propose in this paper to separate the different degraded forms of this porphyrin by using polysulfone membrane polymer type. In this paper are presented some analytical results of verteporfirin before and after passing degraded form of the porphyrins over these membranes.

This paper presents a modification study of recovered polypropylene by melt alloying with a styrene-isoprene block-copolymer blend, thus ensuring the optimum conditions to obtain polypropylene composites with performance impact strength.

The paper describes the investigations related to the fabrication and characterization of two new plastic pyrotechnic compositions using solvent-free polyurea as binder. These solvent-free polyurea binders allow wet or dry pressing of the pyrotechnic compositions. The rubbery texture of the polyurea binders minimize the risks associated to the dry pressing of other brittle binders. A comparative theoretical and experimental study between these new types of binders and a conventional binder has been performed, in order to establish the improvements that could be brought to the pyrotechnic compositions, in terms of safety and performance.