Plastic compounds have been used for several decades to generate anatomical constructs for the training of new surgeons and medical students alike. The present study seeks to highlight the advantages and disadvantages of two different plastic compounds (Technovit 7143 and Epoxi BIODURÒE12) used to create corrosion casts of the vascular branching patterns in free muscle flaps. Porcine latissimus dorsi muscle free flaps were used in this study to create corrosion casts of their vascular branching tree by injecting the two different plastic compound into the main arterial supply. The casts generated by Epoxy BIODURÒ E12 have superior qualities compared to the casts injected with Technovit 7143, because the injection process is smoother at all branching levels, without dilation, strictures or intramuscular extravasation of the injectable plastic compound. The corrosion casts resulted from injecting Epoxy BIODURÒ E12 exhibit better elasticity and better resistance to mechanical handling compared to the ones injected with Technovit 7143.
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Developing biomaterials with optimal loading properties and controlled release of drugs is a priority of medical research. Clinoptilolite is a natural zeolite used in various industrial processes. Its texture and structure recommend its use as a biocompatible matrix for the development of modified release drug delivery systems. The present study aims to develop and characterize modified-release systems based on bexarotene loaded clinoptilolite. Bexarotene is a retinoid that is used as an anticancer agent in the topical treatment of cutaneous T-cell lymphoma. By adding bexarotene to these systems, skin delivered antineoplastic therapy with bexarotene can be improved. Clinoptilolite was obtained by purifying the volcanic tuffs from Mirsid quarry, Salaj Romania. After thermal and chemical purification, two monoionic forms of clinoptilolite were obtained. They were labeled as Na-CLI and H-CLI, respectively. Their texture and structure were characterized by specific methods. Subsequently, these forms of clinoptilolite were used as hosts for bexarotene loading by wet impregnation. The obtained results showed that the two modified-release systems Bxt@Na and Bxt@H, respectively, have no incompatibilities and provide prolonged release of the drug.
Grape marc, also known as grape pomace, is one of the most investigated bio-wastes derived mainly from grape skin and seeds, which is produced as a by-product of winemaking on the million-ton scale annually. Presently, the most important high-value use of grape pomace is in the production of oenological tannins, widely-used additives in the food and beverage industry. This article studies the possible use of grape waste in the plastic industry, as request of the consumer for green plastics with regards to environmental impact, and in the case of packaging, to improve the shelf-life and safety of the products contained. 4 white grape varieties and 4 red grape varieties (most cultivated grape varieties in Romania) were taken into study, processed using different technological methods and the spent material (grape skins and seeds) were analysed regarding their total phenolic compounds and total tannins.
The spectroscopic and photochemical properties of polyurethane coumarine (PUC) in solid state were investigated at room temperature under once-photon excitation. One photon induced photocycloaddition of PUC was investigated and the AFM and spectroscopic FTIR analysis confirmed dimer formation. The AFM analysis shows that the fotodimerization process occurs at the surface of polymer films. The polyurethane coumarine film on CaF2 unirradiated and irradiated underline both the fotodimerization of the polymer films as well as the photoclevage of the polyurethane coumarin.
In this paper it will be presented the deformations analysis using the finite element analysing method, for an armchair seat redesigned from an wooden original model, into a polyurethane more compact structure. In order to perform the testing required, a 3D PU design was made after the wooden model. This new design was made in such way which will enhance the productivity, to be more compact, more lightweight and also more resistant than the original design.
In the paper are presented the experimental researches made in order to obtain a new titanium alloy - Ti15Mo5W used for medical applications with improved mechanical characteristics and modulus of elasticity. In this regard Ti15Mo with addition of W alloy was designed with the intention of obtaining b-Ti phase stability. For this, we studied the influence of: the bond order, energy level of metal d-orbital, ratio of valence electrons/atom and influence of the addition of W. After designing the alloy compositions and setting the parameters, the Ti15Mo5W composition was chosen to run the experiments. The experimental Ti15Mo5W alloy was obtained by vacuum arc remelting technique using Ti, Mo and W high purity metals. The alloy was characterized by SEM, EDS and tested for Vickers hardness and compression. The microstructural characterization of the alloy proved to be homogeneous, and the mechanical characterization highlighted the obtaining of an alloy with a low elasticity modulus of about 30 GPa and an average hardness of 320 HV.
The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.
The paper presents the results of the experiments on obtaining a composite material to be used in manufacturing brake shoes for the rolling stock. The aim was to replace the classical material used at present for the manufacturing of brake shoes: cast iron with a specially designed composite material. Six recipes have been tested and compared to a standard sample made of phosphorous cast iron. The wear trials carried out in laboratory conditions on the experimental test rods have led to results that entitle further experiments that implies the manufacturing of brake shoes made of the composite material in question.
In this work, we focused on the potential of biogenous mineral from Cuttlefish bone for inducing biomimetic mineralization with further biomedical applications. We demonstrate the formation of strong and flexible hydrogels via physical immobilization of cuttlefish bone powder in the presence of bovine gelatin and alginate. The properties of hydrogels loaded with biogenous mineral, with a commercial bone substitute, with commercial nano-hydroxyapatite and in situ generated hydroxyapatite. In vitro cell adhesion tests demonstrated that the new developed hydrogels showed a promising cell adhesion.
The first part of the paper presents the influence of the processing temperature by injection of HDPE, of PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when other factors that can influence the injection remain unchanged. The second part of the paper presents the influence of subsequent pressure by injection of HDPE, PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when the other factors remain unchanged. The HDPE samples were obtained at the following injection temperatures: 180, 190, 200, 210, and 220°C, and at the following subsequent pressures: 800 bar, 900 bar, 1000 bar, 1100 bar, and 1200 bar. The PMMA samples were obtained at the following injection temperatures: 220, 230, 240, 250, and 260°C, and at the following subsequent pressures: 450, 550, 650 , 750, and 850 bar. The PC+ABS samples were obtained at the following injection temperatures: 230, 240, 250, 260, and 270°C, and at the following subsequent pressures: 500 bar, 600 bar, 700, 800, and 900 bar. The G-Series Basic Hardness Modulus at a Depth method was used to obtain the indentation hardness and the indentation modulus. It was observed that by increasing the processing temperature and subsequent pressure, in the case of HDPE, leads to an increase in indentation hardness and in indentation modulus. It was observed that increasing the processing temperature by injection in the case of PMMA, from 220 to 250°C, leads to a slight increase in indentation hardness and in indentation modulus, whereas increasing the subsequent pressure of PMMA, from 450 bar to 850 bar, leads to a slight decrease in indentation hardness and in the indentation modulus. Increasing the processing temperature by injection in the case of PC+ABS, from 230 to 250°C, leads to a slight increase in indentation hardness and in indentation modulus. By further increasing the processing temperature by injection, from 250 to 270°C, leads to a decrease in indentation hardness and in the indentation modulus. Alternatively, increasing the subsequent pressure from 500 bar to 900 bar leads to not only a decrease in indentation hardness but also to a decrease in the indentation modulus.