Investigating the Deformation Parameters of PVC Fitness Balls in Relation to the Height and Body Mass Index of the Users
The aim of the study was to measure the goniometric differences of the knee and hip joints and the changes regarding the features of fitness balls by taking into consideration its circumference and the vertical and horizontal diameters under the action of the body weight. The outcomes of the study have resulted in the creation of a table with reference values regarding the size of fitness balls in relation to the height and body mass index of the subjects.
Comparative Analysis of Two Bioplasticizers Used to Modulate the Properties of PLA Biocomposites
The present paper deals with a comparative study on the influence of two different bioplasticizers: acetyl tributylcitrate (ATBC) and LAPOL108 on the mechanical and antimicrobial properties of poly(lactic acid) PLA containing 1 wt.% chitosan. PLA based biocomposites were investigated by means of processing behavior, FT-IR spectroscopy, DSC analysis, tensile and barrier properties, migration in food simulants and antifungal activity. Based on the obtained results it can appreciated that the properties of the PLA based biocomposites could be appropriate for designing flexible or rigid food packaging depending of the bioplasticizer used.
Mechanical Stress Exploration Inside of Dental Filling Materials by Means of Electronic Speckle Pattern Interferometry / Shearography
Possible causes of microleakage and microfractures of dental fillings are often in the center of many academic research and investigations. Some authors found that one important cause of microleakage is the contraction/ shrinkage of the filling materials during polymerization. The purpose of this study is to demonstrate that microcracks and consequent microleakage is influenced by mechanical stresses occurring inside of dental filling materials and at the interface of the dental cavities and dental filling materials. We also tried to evaluate the deformation of some dental filling material types during mechanical loading. Cylindrical specimens were made of different types of dental filling materials, namely microhybrid composites and glass ionomer cement. Some extracted teeth were prepared with class II cavities, and filled. The lateral swelling of the tested specimens and the deformation of the filled teeth during vertical axial loading was measured with an optical method, ESPI/ Shearography.Of the tested specimen, the least deformable dental filling materials were the composite materials. During occlusal vertical loading of the filled teeth, there were found that mechanical stresses were different inside of the filling material than inside of the walls of the dental tissues, mechanical stressed being concentrated at the restoration interface. The ESPI/Shearography meth ode proved to be very useful for investigation in this field. Due to mechanical stresses accumulating at the interface of the dental filling material and the walls of the dental cavity, it is possible that later microcracks to appear due to masticatory forces.
In vitro Testing of Experimental and Commercial Bracket Bonding Materials
The aims of our study were to assess the cytotoxic effect of five orthodontic bonding materials, in vitro, on HUVECs to study the induction of apoptosis and inflammatory response generated to assess the shear-bond strength of the 5 tested materials in order to quantify their performance. Standardized samples from each material were obtained and incubated with HUVEC cells for 24 and 72 h immersed in complete medium. Cell viability was determined by means of MTS method. Active caspase 3 and TNFa protein levels were measured through ELISA techniques. The shear-bond strength was tested on 60 extracted premolars which were bonded with the same type of bracket, using the 5 different materials. Statistical analysis Student T-tests, Chi-square and Anova tests were used for results interpretation. Cell viability was decreased with material exposure in a time dependent manner. All materials exerted cytotoxic effects, the experimental materials showed a significantly higher decrease in cell viability at the 72 h reading. Shear Bond strength was superior for the resin commercial bracket-bonding materials. The study shows that orthodontic adhesives’ cytotoxicity and physical performance is related to their chemical properties and proves that all orthodontic practitioners should use freely their material of choice on condition they are aware of all its’ properties.
The Use of Polypropylene Mesh in the Reconstruction Techniques of the Thoracic Wall After Resections of the Thoracic Wall
The thoracic wall resections for tumoral affections are laborious surgical interventions characterized by a high mortality and mobility. In order to create this paper we created a observational retrospective study in which we included 21 patients that have underwent parietal thoracic resections for tumoral affections. In all the patients we practiced the reconstruction of the thoracic wall using polypropylene mesh. The main postoperative complications were: seromas (14.28% of the cases), hematomas (9.52% of the cases), wound infection (4.76% of the cases), pneumonia (23.8% of the cases), respiratory failure (23.8% of the cases), paradoxical movement of the thoracic wall (52.38% of the cases). No deceases were recorded. In conclusion, the use of polypropylene mesh in the reconstructive techniques of the thoracic wall after thoracic wall resection represents a viable method, with good respiratory functional results.
The Effects of Magnetic Nanoparticles Incorporated in Polyelectrolyte Capsules
Polyelectrolyte multilayer capsules are synthesized comprising of 12 total layers each containing a single layer of iron oxide nanoparticles in shells 4, 6, 8 or 10. A protein-labelled dye is embedded in the calcium carbonate template core as a model for the encapsulation of a drug. The core is dissolved after 6 layers are formed. Two types of magnetic nanoparticles are incorporated into various capsule shells: ferric oxide (Fe2O3, 50 nm) and iron oxide (Fe3O4, 15 nm), a 1:1 (vol.) mixture of the two types of nanoparticles suspensions is also used. Nanoparticle inclusion reduces the capsule sizes in all cases with the order of effect Fe3O4 [ Fe2O3 [ Fe2O3/Fe3O4 mixture. When Fe3O4 or a Fe2O3/Fe3O4 mixture is incorporated in layer 6 the reduction in size of the final capsules is less than expected. The number of surviving capsules containing nanoparticles are lower than control regardless of which of the nanoparticles is used but here the effect of Fe3O4 or a mixture of the two types of nanoparticles incorporated in layer 6 was slightly out of step. The amount of iron incorporated is almost the same regardless of which shell the nanoparticles were incorporated but the iron content using 50 nm nanoparticles is generally slightly higher than that obtained with 15 nm nanoparticles.
Polypropylene Mesh in Minimally Invasive Treatment of Female Stress Urinary Incontinence
Stress urinary incontinence in women is a condition widely encountered in the entire world with a prevalence between 12.8% and 46.0%. Stress urinary incontinence is a public health problem causing a significant decrease in quality of life, involving social, physical, psychological, occupational and sexual suffering of patients. The minimal invasive treatment of the stress urinary incontinence (SUI) consists in fixing a suburethral polypropylene mesh (SPM) in retropubic (TVT) or transobturator (TOT) space, in order to regain the pelvic support of the urethra, with the consecutive augmentation of the pressure of urethral closing during effort. The objective of this paper is to present the advantage of SPM in the SUI treatment in the eleven years’ experience of Department of Urology Sibiu.
Experimental Research on the Triangular Lattice Type Polymer Based Composites Structures for Sandwich Panels Construction
The paper presents experimental results on the mechanical behaviour for a polymer based composite sandwich panel tensile and bending tested, which uses, one by one, a cellular composite core fabricated by additive manufacturing of four different types of polymeric materials: ABS (acrylonitrile butadiene styrene), PC (polycarbonate), PLA (polylactide) and CF (polylactide + 40% carbon fibre), with the thickness of 3 and 5 mm. This research focuses on comparative analysis of the core thickness increase effect on the structure’s strength. Experimental tests carried out on standardized test-pieces with specialized laboratory equipment, are highlighting similar mechanical behaviour and are showing also an increase of composite stiffness with the increase of core thickness, at the same time, the arrangement of the cellular lattice structure has a significant effect on the structural strength.
The Effects of Magnetic Nanoparticles Incorporated in Polyelectrolyte Capsules
Most studies and experimental tests performed upon orthopaedic bone cements are related to their use in everyday conditions when usual wears are due to compression and fatigue. The present paper deals with some special situations occurred during the patient’s recovery after the surgery. The recovery activities and motions may induce different types of loads, like tensile, during stretching and relaxation techniques, especially in the joint insertion area. These situations are insufficiently researched, but they represent one of the main concerns of the medical staff involved in recovery and rehabilitation. Besides the study of mechanical properties for these special situations the paper proposes also a thermal analysis during preparation of the polymethylmethacrylate(PMMA) as it can be the trigger of serious health issues (necrosis, blood circulation problems, BCIS, etc.) due to the exothermic polymerization reaction. The monitoring method proposed for the temperatures developed during the polymerization may avoid the aforementioned issues.
Innovative Poly Methyl Acrylate Intubation Device Used in Difficult Airway Instrumentation of Patients with Pharyngeal Tumors
Difficult airway management is a common situation when the anesthesiologist deals with patients with hypo pharyngeal tumors. The volume of the tumor usually covers the glottis plan and modifies the local anatomy, making the intubation process difficult or almost impossible. Intubation laryngoscopes developments are minor and adding a CCD camera at the tip of the laryngoscope is the best improvement made in our days. Today, on the market, an intubation device designed properly for the patients with extensive hypo pharyngeal tumors does not exist. The aim of the paper is to present an innovative device designed for patients with hypo pharyngeal tumors.