Browse Articles

Tests on wearing clothes are complex methods of analysis that mainly consist of recording the physiological reactions in the body. An early supervision of these physiological reactions, at a physical charge and under certain climatic conditions, ergometrically shaped, provides precious information on the human body and its status, as well as on the worn clothes. Physical parameters of the environment and biometric parameters were measured during the wearing tests. There were tested 5 subjects, students, for wearing 5 textile garments. In the performed tests there were determined the following parameters: cardiac frequency, respiratory frequency and energetic consumption. Keywords: clothing, wear tests, warm environment, dynamic conditions, comfort, evaluation, biometric parameters

Domestic pigs were frequently used in training centers for residents and students in medicine for the stenting procedures at the level of renal arteries. On 12 domestic pigs (all male) with an average weight of 34 kg (30.0-39.9 kg), were analysed the morphological parameters of femoro-iliaco-aorto-renal arterial system. An analysis of the pelvic segment length (I-II-III) and abdominal (IV), shows almost perfect equality of the lengths of the two segments on the right (76.26 ± 5.30 mm / 76.21 ± 4.51 mm) and a mean difference of 1.25 mm in favour of segment IV (abdominal) (75.53 ± 5.10 mm / 76.78 ± 4.44 mm), a difference that correlate with left renal artery cranial origin. Pelvic diameter portions of femoro-iliac arterial axis increase linear in average by 10% per segment (from 3.99 ± 0.40 mm ± 4.89 in segment I at 4.89±0.33 mm in segment III). Increasing the diameter from the segment III to segment IV is approximately of 30%. The diameter of the proximal part of renal artery (3.46 ± 0.36 mm) on the studied material is smaller than the diameter of the proximal part of the external femoral artery (segment I) (3.99 ± 0.40 mm), making it easy retrograde catheterisation of femoro-iliac-aorto-renal arterial axis. Knowledge of the morphological parameters of femoro-iliaco-aortic arterial axis and their evolution in correlation with the weight of laboratory animals -domestic pigs- favours the achievement in good conditions to arterial catheterization for proximal renal artery stenting. Keywords: corrosion casts, domestic pigs; femoro-iliaco-aorto-renal axis; morphological parameters; stenting training

The purpose of this work was the detailed study of morphological biodegradation and the citotoxicity effect of some experimental biomaterials. The study has four experimental biomaterials based on polylactic acid, polyethylene glycol, tricalcium phosphate, chitosan and hydroxyapatite in different percent cured in air followed by heat treatment at 1200C. The experimental biomaterials were characterized by AFM (Multimode V-SPM, Veeco) and SEM (Q130 -FEI Company) microscopy. For the citotoxicity were used cell cultures of normal human fibroblasts and the viability testing was made with trypan blue. According to the experimental results, the biomaterial with highest percent in polylactic acid presents a high degradation, compared with the rest of the biomaterials which have HA in composition, who decrease this process. Fibroblasts cell culture showed good adhesion to the surface of the biomaterials. The viability of the biomaterials increases at 48h compared with 24h, which suggest the absence of the materials cytotoxicity. Our results sustain idea that biomaterials based on chitosan with additions can be successfully used for further studies in reparative medicine. Keywords: chitosan, biodegradable polymers, hydroxyapatite, SEM, AFM, citotoxicity

The paper aims at evaluating the impact of technological parameters of a drilling process on the parameter of surface roughness Rz (maximum height of roughness profile) of wood-based material (WPC – Wood Plastic Composite). During drilling with tools 3.0, 5.0 and 7.0 mm in diameter, the spindle speed nc and feed rate f were changed. The evaluation of statistical significance was performed using the ANOVA mathematical tool (two-way with repetition). Using a simple conversion, it is possible to assess which of the set parameters affects the final surface quality, which serves as supporting information for the work of an engineer. Keywords: statistical evaluation, composite, surface texture

In accordance with Terminologia Anatomica, the renal artery gives rise of two branches: anterior branch and posterior branch. Anterior branch gives rise to four segmental arteries: superior, anterior-superior, anterior-inferior and inferior; posterior branch continues with posterior segmental artery. On a total of 150 renal corrosion casts was examined the artery of inferior segment. Three morphological types have been highlighted: Type I, in which the inferior segmental artery originating directly in the trunk of the renal artery (8.0% of cases); Type II, in which the inferior segmental artery arises from the anterior branch of the renal artery (87.33% of cases); Type III, in which the inferior segmental artery arises from the posterior branch of the renal artery (4.67% of cases). In 33.33% of cases the inferior segmental artery arises independently from the trunk or renal artery branches (anterior or posterior). In 66.67% of cases, the inferior segmental artery realizes a common trunk with one or two other segmental arteries (in type II). Knowledge of these aspects is important both to investigate morphological imaging and preforming partial resection of the renal parenchyma. Keywords: kidney; corrosion casts; inferior segmental artery; variations

The aim of this study was to evaluate the role of local administration of vitamin D in influencing the rate of orthodontic tooth movement. Six dental arches were included in this study. Every arch was divided intro two hemiarches: experimental hemiarch and control hemiarch. The canines were included in this study. Control canines received orthodontic therapy compared with experimental canines which received orthodontic therapy associated with local administration of calcitriol (1,25 dihydroxycholecalciferol). The rate of tooth movement was measured in both hemiarches. We noticed a difference between the rates of orthodontic treatment in experimental and control hemiarches respectively. This might be attributed to local administration of calcitriol (1,25 dihydroxycholecalciferol). Keywords: bone remodeling, orthodontic tooth movement, vitamin D, bone desorption, bone apposition

Partial devulcanization of rubber crumb spent was performed in the presence of oxide nanoparticles. Nanoparticles on the basis of CaO and ZnO were prepared by dry grinding in a laboratory planetary mill and nanoparticles on the basis of Fe3O4 were obtained by precipitation. The distribution of particle sizes based calcium, zinc and iron were measured by dynamic light scattering. Devulcanization of the rubber crumb was carried out in a batch system at a temperature of 200°C and the sulfur content of rubber decreased more than 15 times after devulcanization. Homogeneity of bitumen, determined by fluorescence microscopy, was superior in case of modification with devulcanized rubber compared to the case of modification of bitumen with vulcanized rubber. Adhesiveness of bitumen road increases significantly after modification with desulfurized rubber compared to the case of bitumen modified with vulcanized rubber. Keywoords: waste, desulfurized rubber, bitumen modification, nanoparticles

The prevalence of soft tissue graft in anterior cruciate ligament (ACL) reconstruction, as well as the preference for bioabsorbable fixation continues to grow in clinical practice. This paper presents one complication related to biocomposite screw fixation used in ACL reconstruction found in clinical practice associated with a retrieval analysis of a broken biocomposite interference screw made by PLLA-HA (75% PLLA, 25% HA), arthroscopically removed from the tibial site at 8 months after ACL reconstruction with soft tissue autograft in a young patient. The fragment of broken screw was analysed in terms of surface and structural analysis following an established implant retrieval protocol. The retrieved implant surface shows cracks and breakdown signs characteristic to the final phase of resorption but incomplete probably due to biomechanical stress. The present study is important since it is one of the few cases recorded for both a composite implant as well as for an early complication, supporting the idea that the breakage of biocomposite screws should be considered during ACL reconstruction. Keywords: biocomposite screw, biodegradable polymer, ACL reconstruction, retrieval analysis, SEM

The paper presents the results obtained by the authors for the mathematical modeling of the mechanical behaviour variation of the composite material with polymeric or elastomeric matrix and reinforced with protein fibers (CFP), depending on the concentration of the reinforced material. The mathematical model of the main mechanical properties of a composite material allows optimal approximation variants of material that is as close to that required in a particular field. The method proposed in this article is generally applied to the composite materials and is valid not only for the case of mechanical properties dependence of a single parameter (the concentration of a constituent) but in the case of dependence on several parameters, case in which the possibilities of achieving a favourable variant are much larger and more accurate. In the category of free parameters of the mathematical model can enter all the constituents’ concentrations, but, in addition, also important are the technological parameters: temperature in the manufacturing process, the reinforced material granulation, the degree of stirring, pressure, etc. Keywords: CFP, mathematical model, variation, mechanical properties, optimal variants

This paper presents a method to improve the performance of glass fiber processing by cutting of the fiber reinforced polymeric materials based on the application of ultrasonic vibrations on the cutting tool. General conditions of the process are established and, based on the analysis of the processing mechanism, the authors provided the fundamental condition for the selection of the cutting speed values in the case of ultrasonically assisted cutting of glass fiber reinforced polymeric materials. The paper also presents the theoretical foundations of rising the macrogeometric accuracy of ultrasonically assisted cutting in the case example of the universal grip turning. Keywords: polymeric materials, ultrasonic cutting, glass fiber