Volume 53, Issue 4

Abstract: The aim of the present work was to monitor the adsorption of thyamine hydrochloride (VB1) onto halloysite (HNT) nanoclay in different conditions (contact time, initial pH, temperature and initial concentration). The HNT-VB1 materials were also analyzed by FTIR, TGA, TEM and the release of VB1 was monitored in two different simulated body fluids. Three isotherm models were used to determine the adsorption mechanism of VB1 onto HNT. The Langmuir model showed that the adsorption process is endotherm. The Freundlich adsorption model confirms that this is a favorable process. The adsorption of VB1 onto HNT is a physical process according to Dubinin-Radushkevich isotherm. The release of VB1 from HNT takes place by Fickian diffusion and it was monitored for 24 h. The highest amount of drug released (35%) was registered in simulated gastric fluid (pH 1.2).

Abstract: Nowadays, membrane technologies are becoming more frequently used for separation of wide varying mixtures result from a lot of industries and can compete successfully with traditional schemes. The aim of this paper was to analyse the use of ultrafiltration with polypropylene hollow fibre membrane in the chemical physical systems instead of Granular Activated Carbon (GAC) filtration. A process data collection was performed and integrated with a characterization of the process effluents in terms of treatability and reusability. In order to evaluate properly the wastewater loading, an analysis course was set. The samples have been gathered for two years; instantaneous samples were drawn from the influent and treated wastewater. Based on daily average values, a general average has obtained. The experimental data were statistically analysed and the average values of the investigated parameters. It was found that ultrafiltration is a good process solution before discharge of the effluent.

Abstract: The paper describes a comparative experimental - numerical analysis to study the vibration behavior of a fiberglass/polyester composite box housing electronic components inside a satellite. A finite element model was developed in order to predict the natural modes and the values of the natural frequencies of the structure. In order to perform the numerical analyses, specimens made of the analyzed composite material were tested to obtain the elastic constants. The numerical values of the natural frequencies were further compared to those measured experimentally using a PULSE modal analysis system. The differences between results were less than 9%, validating thus the proposed numerical model, which can be further used to predict the behavior of the subassembly subjected to other loads occurring during the launching phase and on the orbit, as accelerations and/or thermal cycles. Since the order of magnitude of the first natural frequencies is important in understanding and evaluating the performance of subassemblies mounted inside satellites, such a study is necessary in the design phase of these structures.

Abstract: In order to analyze the effect induced by encapsulating the drug in liposomes, comparative studies were performed for control hydrogels and complex systems (the same hydrogels containing liposomes). The results showed that the use of liposomes entrapped within chitosan hydrogels allows a strong decrease of burst effect and, moreover, the mechanism of drug release is a complex Fickian diffusion, consisting of drug diffusion through the swollen hydrogel and/or water filled pores, being continuously fed by calcein loaded in liposomes.

Abstract: Engineers think twice before using plastic bearings in their designs, because they have trusted steel bearings for years or because they think plastic can’t handle demanding applications or environments. Plastic bearings can endure extreme temperatures, heavy loads and high speeds and offer more freedom when it comes to maintenance. Their resistance to dirt, dust and chemicals make plastic bearings a viable steel replacement. Plastic bearings can reduce costs up to 25%, they are highly wear resistant, with a low coefficient of friction and they can replace pricier alternatives in many applications. Plastic bearings also do not typically need lubrication unless steel balls are used in combination with plastic races and are designed to maintain a low coefficient of friction during the life of the bearing. Compared to steel bearings, which can become pitted and have a higher coefficient of friction, plastic bearings last longer. Also, plastic bearings can be used in wash-down applications, salt water and harsh chemicals without decreasing performance. Water can be considered a lubricant for plastic bearings [1].

Abstract: This paper introduces some results of the researches that the authors conducted in the field of using plastic materials for plating the surfaces of the guideways for heavy duty machine tools. There are mentioned theoretical aspects about the calculation and selection of these guideways and the results of the experimental researches performed on the occasion of the remanufacturing of a rotary table intended for the machining on two axes of large mass and overall size workpieces, specific to heavy industry. It is also shown the technology of assembling and machining the plates made of plastic materials. It is about the translational sliding guideways and about the rotational guideways too. They operate with intermittent, continuous or hydrostatic lubrication. The research results can be also applied in the case of remanufacturing of other heavy duty machine tools such as: standard or vertical lathes, Gantry type milling machines, grinding machines or table type HBM-s and floor type HBM-s etc.

Abstract: Clinical performance of restorative materials and their adhesive interfaces can be affected by erosion after rehabilitation of erosive lesions. The aim of the present in vitro study was to evaluate the erosive wear resistance and adhesive bond strength of direct restorative materials, using four different testing tools. Four aesthetic dental filling materials were included in the study: a universal nano-filled composite, a light curing posterior filling composite resin, a tooth-coloured polyacid modified composite resin (compomer) and a coloured compomer indicated in restorations of deciduous teeth. Fifteen specimens were prepared according to each of the four tested restorative materials. Following manufacturers’ instructions for the manipulation/mixing of the materials, adhesive systems and unset pastes were placed in cavities of 4mm length, 3mm width and 1mm depth prepared in bovine extracted teeth and cured. After 24 hours of rehydration in distilled water, each group was immersed in erosive solutions chosen for testing: 1% citric acid and 0.02% phosphoric acid. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used in order to analyze the degrees of erosive wear of the materials following exposure to the various erosive solutions. Also, microtensile bond strength (mTBS) was made and the obtained data was analyzed by one-way ANOVA test and two-sample t-test, with a level of significance that was set at p[0.05. Experimental results reveal that the dental filling materials showed different behaviour under the same erosive conditions. These findings suggest that erosive wear resistance of direct dental restoratives could influence their longevity in intraoral acidic conditions.

Abstract: According to gestational age, two groups were formed: group A (abortion) formed of 19 patients diagnosed with risk of abortion (gestational age < 23 weeks and 6 days) and group B (birth) formed of 32 patients diagnosed with risk of premature birth (gestational age > 24 weeks). We were interested in detecting adverse reactions and complications related to the use of cerclage pessaries and also to determine if this procedure is efficient in preventing premature birth. In addition to the clinical part of this study, we evaluated the mechanism of interaction of the cerclage pessaries with the fluids and the vaginal mucosa by analyzing the structure, design and surface of these devices. Cerclage pessaries are efficient in preventing premature birth. In order to decrease the number and severity of the adverse reaction related to the use of these intra-vaginal devices regular follow-up visits are indicated. Re-sterilization by ethylene oxide procedure of vaginal pessaries is prohibited because it severely modifies the surface of these apparatuses.

Abstract: Nowadays, scientists are making great efforts towards increasing fuel efficiency and for this, aluminium and its alloys are one of the best available options, sustainable aluminium items being able to lower greenhouse gas emissions and save energy expenses in a wide range of structural applications. Equal-channel angular pressing (ECAP) is the main severe plastic deformation (SPD) technique for obtaining ultra-fine grained (UFG) and nanostructured materials (NM), the advanced grain refinement obtained by SPD substantially enhancing microstructural and physicomechanical characteristics for the processed material, therefore arising the potential for minimizing the weight and dimensions of the items being produced. In our study, a commercial 6063 Al alloy (T1 condition) was pressed at room temperature for several passes, the ECAP processed and as-cast samples being microstructural investigated and mechanically tested. Ultimate tensile strength, yield strength, strength to fracture and maximum elongation to fracture were determined. The obtained fracture surfaces were investigated using scanning electron microscopy. For the severely deformed 6063 Al alloy, multiple correlations between the key processing parameters and the resulting microstructure and mechanical behaviour were determined. It was shown that SPD/ECAP can be used as an advanced tool in fabricating sustainable lightweight aluminium products for low environmental impact applications.

Abstract: The outcome of the study is reducing the weight of a centrifugal rotor by manufacturing one out of CFRP composite. The paper presents the design study results obtained for the composite centrifugal rotor mold. CAD design of the rotor assembly and the mold were performed and one 1:2.5 scale mold for a single blade was manufactured. Mold material selection study, was performed based on critical requirements related to advanced composite processing and cure conditions. The selected mold material was epoxy Necuron material(s). The 1:1 scale 3D model mold section was designed and obtained in ABS plus using 3D printer.

Abstract: The purpose of this paper is to prove that the use of synthetic meshes in the treatment of pelvic organ prolapse involves specific complications. Pelvic organ prolapse occurs as a result of the distention or rupture of a weakened, inelastic connective tissue that is a major compound of fascia and ligaments which make up the support and suspension system of pelvic organs. Pelvic organ prolapse has genetic determinism and so patients who suffer from it produce a poor quality collagen or it may happen due to premature aging. The risk for a woman to develop various stages of prolapse is appreciated to be 11% and the risk of relapse is 29.25%. Unlike in case of other surgical treated afflictions, pelvic organ prolapse has a very high risk of relapses that need surgical cure - 17%. The failure rate of the traditional surgical treatment using native tissues is 58% for the anterior pelvic compartment. Given the circumstances strengthening the weakened fascia and ligaments using biological grafts or synthetic ones proved itself necessary. The first augmentation attempts using synthetic meshes were performed by Manhes in 1990. Currently the synthetic meshes are widely used and have good outcomes, but they also have specific complications. For transvaginal interventions reconstruction using meshes is superior to the procedures that use native tissues. Surgical treatment for the pelvic floor defects consisting in synthetic mesh implant shall not be recommended unless the benefits exceed the risks for every case in particular. Based on our experimental results, scanning electron microscopy appears to be a very useful tool for surface analysis and retrieval studies of the surgical mesh used in the treatment of pelvic floor defects. Also, we find that the mesh erosion is the main adverse effect in the surgical treatment of pelvic floor defects and this appears due to the polymeric mesh materials modifications.

Abstract: In this paper, we have studied the vibrations damping capacity for some composite materials that have as matrix a combination of Dammar and epoxy resin. We have used flax, cotton and silk fabrics as reinforcement materials. For comparison, half of the studied materials were made with Sandarac core. We have suggested a mathematical model for studying the vibrations of composite bars with three layers and rectangular section, based on a bar section non-linear strain. Singularizing the obtained model, there are achieved the Timoshenko equations for bars with rectangular section. For the considered bars, we have experimentally determined the damping and loss factors.

Abstract: The purpose of this paper is to study the performance of composite and structures materials (laminates composites reinforced with carbon fiber and sandwich materials with laminated composite faces and foam core) by theoretical and experimental analysis on damping capacity vibration. Experiments were carried to determine the elastic and damping characteristics of composite materials on a small-scale configuration of a machine tool structure having the purpose of knowing the damping vibration ability of a column position on a Polypad structure.

Abstract: Two types of sutures made by two different biopolymers were tested in terms of hydrolytic biodegradation in phosphate buffered saline solution, which simulates the physiological conditions, varying the pH of the medium and the immersion time. The determination of the degradation rate was conducted by measuring the weight loss of the sutures. The study revealed that both investigated surgical suture exhibit quite different hydrolytic degradation at various immersion times and pH level, a more intense degradation being recorded in the alkaline environment.

Abstract: The dimensional stability and structural integrity of composite luting cement are key factors of clinical performance and intraoral durability. The solubility both in water and saliva of a composite luting cement is influenced by the absorption of liquid by that cement. The aim of this study is to evaluate the solubility and water sorption of three different adhesive cements (Variolink, Nexus, Dualcim) in two different environments: artificial saliva (Artisial/Biocodex, France) and distilled water at different timed intervals. Water sorption is dependent on the chemical composition of the material, the time and the immersion medium.Water sorption was different for the three cements tested, at all three time periods, both in distilled water and in artificial saliva. ANOVA test results show that for all three materials used there are statistically significant differences (p < 0.002) between the mean values for the three tested periods, both in terms of solubility and absorption. Between 7 and 14 days the water sorption continued to increase significantly for all materials tested, showing a stabilizing trend in most cases only between 14 to 21 days.

Abstract: The purpose of this in vitro study was to evaluate and compare the degree of microleakage of the enamel-sealants interface when used four different materials. Analysis of the penetration of sealing materials shows that they adhere different to the enamel and the characteristics of resin composite materials used in clinical practice as sealants, influencing dental material penetration to the surface once the viscosity of the inorganic filler.

Abstract: Skeleton prosthesis is defined as a complex partial movable restoration, which involves a fixed component (dental bridge cemented on the remaining prepared teeth), and movable component part. Recently, a new high performance polymer, BioHPP, based on polyether-ether-ketone (PEEK) polymer was introduced as dental material for manufacturing the framework of these types of partial dentures.The purpose of this article is to present the results of the clinical trials referring to the benefits of skeleton prostheses wearers’ patients with BioHPP framework. The research has been carried out on 48 patients. The recording of the benefits in the using this polymer for partial dentures, in accordance with seven evaluation criteria, was performed in three dental schools from Romania, during three years, at every three months.The results of survey demonstrate that BioHPP polymer frameworks for skeleton movable restorations present many benefits and advantages, therefore this PEEK type of dental material represent a beneficial new acquisition for the partial edentulous patients.

Abstract: The aim of this clinical study was to investigate the comparative effectiveness of two dental desensitisers based on 2-hydroxyethyl methacrylate (Gluma desensitizer and Shield activ desensitizer), in decreasing the dentinal painful sensitivity caused by cervical erosions.The clinical trial consisted of 63 patients (323 teeth), with minimum three teeth which presented cervical erosion with dentinal hypersensitivity. The sensitive teeth were treated with Gluma Desensitizer-Heraeus Kulzer (first batch of teeth), Shield activ desensitiser (second batch) and distilled water (third batch of teeth=control group). We effectuated in total three desensitisation sessions, at 5 days difference. The level of cervical dentinal hypersensitivity (CDH) was determined in six sessions, after the patient’s response to air-blast stimuli. We used the Visual Analog Scale (VAS) to assess the CDH. The results proved the effectiveness of used desensitizing agents in treating CDH in the first and the second batch of teeth, in comparison with the control group teeth. We noticed that after the second application of Gluma and Shield products significant differences, in comparison with the baseline, appeared. After 3 month follow-up, we ascertained that both products induced the decreasing of CDH. No significant differences were recorded between the two products. A placebo effect in reduction of CDH was observed in the group of teeth treated with distilled water. Both dentin desensitizing agents have proven effective in reducing CDH.

Abstract: We report the case of a patient with simultaneously two intrauterine devices with different mechanism of action. By cumulating the effects and adverse reactions of the two intrauterine devices, the patient had severe dysfunctional bleeding and pelvic-abdominal pain. Using scanning electron microscope, we analyzed the surfaces of the two retrieved intrauterine devices in order to establish the physio-pathological mechanisms that occurred and lead to a local but also a hormonal disorder in the reported patient. We would also like to draw the alarm that a complete evaluation (clinical and imagistic) are mandatory prior to the insertion of an intrauterine device.

Abstract: The paper presents an experimental study on the influence of the polyurea layer on the behaviour of metal plates loaded through air blast while the polyurea coat is placed on the loading face of the plate. To assess the influence of polyurea layer, the permanent maximal deflections of tested plates were used. A strong dependence between the effect of polyurea coating on the permanent deflection and stand-off was found. The analysis based on comparison between theoretical predictive functions and test result have shown that in almost all tested scenarios the bilayered plates results are less promising than the predicted results of monolithic steel plates of equal areal density.

Abstract: The etiology of the TMJ disorders is a very controversial topic in the orthodontic literature. The symptoms include pain, muscle spasms, clicking and limitations of the mandibular movements. This pathology is also known as myofacial pain dysfunction and it appears to be more common in young female patients. Muscle hyperactivity, occlusal trauma and parafunctional oral habits are often associated with this syndrome. There are several noninvasive ways to treat this type of pathology (medication, removable appliances, TENS therapy) but the most common refers to acrylic splints. Nonpermissive or repositioning acrylic splints, that often include an acrylic bite plane, representthe most popular treatment alternative nowadays. These appliances can set the condyle in a centric relation in order to reduce muscle spasm, pain and the levels of cellular hypoxia.

Abstract: Von Mises Stress in a finite element analysis method is widely used by designers because it helps them to check whether their design will withstand a given load condition, in other words, if the maximum value of the Von Mises Stress induced in the material is more than the strength of the material or not. In this paper it will be presented the Von Mises Stress analysis of an armchair seat redesigned from an wooden based model, into a polyurethane more compact structure. In order to perform the testing required, a 3D design was made after the wooden model. This model was made so it will be easier to build, more compact, and with a lower weight and maybe having a more resistant structure compared to the wooden design.

Abstract: The paper presents the experimental research regarding the use in construction field of clay bound earth and wood chips combined with classical binders (cement and lime). New building materials were manufactured (for ground storey houses) by using clay bound and wood chips. The clay bound earth is present all around the Globe. Due to this reason there is one of the most common natural resources of the planet. The wood chips are a waste from wood furniture industry. The paper presents experimental research on mixtures made of clay bound, cement, lime, sawdust and water. Experimental tests were made for: apparent density, bending tensile strengths and compression strengths. The new manufactured building materials have physical and mechanical properties similar to lightweight mortars and bricks. Through clay bound and sawdust reusing a very good impact on environment and life health will be generated. The new building materials studied can be used at non-loadbearing and loadbearing masonry elements. The Batch 4 was the best one, having a bending tensile strength of 3.75 MPa and a compressive strength of 13.41 MPa at 365 days. It has the same mechanical characteristics like bricks made of from burned clay bound. The 25% water percentage is good enough for a satisfactory workability (the material flows to infill the mould); in case of the decrease of the water percentage (especially at 15%), the material has no flow and consequently, is necessary to apply a low pressure (by hand) to infill the mould. A 30% water percentage significantly improves the workability of mixtures.

Abstract: Mode II testing is performed on a polyurethane foam as a particular case of mixed-mode four-point testing. Crack initiation and propagation in Mode II depends on the geometrical parameters of the testing configuration. Numerical XFEM simulations are done in order to clarify the situations in which the crack doesn’t propagate and failure is produced in the region of supports. A combined experimental-XFEM analysis is recommended to fully understand the particularities of the behaviour of cellular materials.

Abstract: This study compares, by means of the finite element method (FEM), the behaviour of the restorations done with the same material, the same adhesive system and under the action of the same force values applied to four 3-D lower premolar finite element models, representing four different cavity shapes. An extracted lower premolar which presented an abfraction lesion has been used. The restoration was achieved by using etch–and-rinse adhesive systems and Giomers. The premolar was scanned and the resulting sections were processed and converted into a 3D digital format. Thus, a model of finite elements which presented a restored wedge-shaped cavity in the cervical dental area was obtained. Then, by modifying the shape and dimensions, there were created another 3 modified-shape cavities. Forces of different magnitudes (90-150N), exerted at a 45 degree angle on buccal cusp, have been applied. If adhesive system tensile strength is about 25MPa, this limit is reached at 120N only for the third model. For Beautifil FO2 the tensile strength is not reached when maximum forces are applied (150N) and for Beautifil II, the tensile strength is reached only for model 4, when a force of 150N is applied. In order to increase the retention of the abfraction restoration, changing the shape of the cavity should be associated with the use of Giomers and adhesive system with tensile strength exceeding 25MPa.

Abstract: Structural and morphological features of compositions based on LDPE which contains different types of fillers for creation of conductive polymer products are presented in this article. Different types of fine metallic fillers, such as Al, Br, Cu, and flake-like graphite were used in this work. Comparative assessment of morphometric characteristics of particulate fillers: area, perimeter, equivalent diameter, shape factor and their distribution on these indicators were performed by methods of optical microscopy and image analysis. Composite films based on LDPE, containing 5% vol. with different types of conductive fillers were obtained by pressing method. It was found that the nature of the filler quantitatively influences on the uniformity of distribution of its particles in composite films. The most structural homogeneity was observed in PE-Gr and PE-Cu composites, while the least - in PE-Br composite. It was shown that the increasing of average particle anisotropy for investigated fillers reduces their heterogeneity of distribution in composite films.

Abstract: The purpose of this study was to develop and characterize the in vitro release kinetics of erythromycin from water-in-oil microemulsion preparations for dermal application. The results obtained confirm that the water-in-oil microemulsion systems based on avocado oil can be used as incorporation and delivery systems for the topical administration of ER in the treatment of skin disorders.

Abstract: This study reports on the in vitro erosive capacity of three different pH chlorinated waters on dental enamel, and the anti-erosive protection conferred by three dental materials (toothpaste, remineralising cream, and fluoride varnish), assessed by scanning electron microscopy. Fluoride varnish provided the best protection, forming a resistant thin film on the enamel’s surface. The observed ultrastructural changes of the enamel surface were low when the tooth paste was used, and more pronounced when the remineralising cream was used.

Abstract: Cobalt based alloys are widely used in medicine, the system CoCrMo being used for partial removable dentures realization. The extension of the applications for these alloys is based either on alloying of the tertiary system with new elements, or to the using of the plastic forming components. Titanium, which is well-known for its biocompatibility property, was used as an alloying element for the system CoCrMo in order to increase the physical-chemical properties of these alloys. Present paper has the aim of establishing the plastic forming behavior of the new alloy from the system CoCrMoTi, with 5.5%Ti, which will be possible used in dentistry. The experiments were realized in laboratory conditions, on a free falling dawn hammer, with high of free falling about H = 0.2 m,, and the falling dawn mass about 71 kg. The determinations were made in the range of temperatures about 1100 – 1250°C, at every 50°C. Finally, the graphics of plastic forming versus temperature and mechanical working versus temperature were drawn. The final conclusion was that the optimum range of temperature for hot working of the CoCrMoTi alloy is 1150 ÷ 1250°C, in which the plastic forming resistance and specific hot working are optimum.

Abstract: The superior machining of waste involves their reuse as raw material for new products. In the research there was aimed to improve the known technological process to reduce costs and increase productivity. Thus, the process was redesigned by introducing new technologies related to shredding of waste respectively de-vulcanization in autoclaves. Shredding technological process has been redesigned by using shredding tools, ultrasonic activated in order to increase productivity, durability of these tools respectively the decrease of energy consumption. There were also conducted researches on the autoclave vacuum after rubber de-vulcanization which allows an increase of reclaimed rubber qualities.

Abstract: The paper aims to approach a problem which occurs when welding the high density polyethylene fittings and pipes used in the natural gas distribution networks. The work presents a finite element numerical analysis of the polyethylene fitting. The geometric modeling was performed using the Catia software, which includes the finite element module and thus eliminating the risk of the possible inconsistencies between the Catia files and other finite element software. There is presented, in parallel, the thermal analysis of the polyethylene fitting employing an infrared camera. Reading both, finite element analysis and thermal analysis conclusions may lead to the solution that should be taken in order to avoid the fracture of the polyethylene fittings during welding or immediately after that.

Abstract: This study has been carried out to investigate a new method to improve metallic implant bioactivity for osseointegration by producing a calcium phosphate (Ca–P) surface layer using an immersion process in the Simulated Body Fluid (SBF) of Polypyrrole (PPy) and Polypyrrole/poly(sodium-4styrensulfonate) (NaPSS) conductive hybrid polymers electrochemically synthesized on Ti6Al7Nb alloy. As formed PPy/Ca-P and PPy/PSS-/Ca-P films were characterized electrochemically by Cyclic Voltammetry (CV), Tafel plots and spectroscopically using FT-IR technique. Also, in vitro cytotoxicity of these new organic/inorganic hybrids films was evaluated by yellow 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay after cultivation in a primary culture of osteoblast cells. The PPy/Ca-P hybrid film showed the best electrochemical stability and the highest value of cell viability.

Abstract: In this work, two commercial block copolymers namely, styrene–ethylene/butylene–styrene (SEBS) and styrene–butadiene–styrene (SBS) with the same amount of styrene were investigated to enhance the properties of recycled polypropylene (RPP) from post-consumer boxes. The amount of elastomer varied from 10 wt.% to 30 wt.% relative to RPP. The elastomer content influence on structural (MFI, DSC, VICAT, HDT, XRD) and mechanical properties (tensile properties, IZOD impact, hardness) of the RPP/SEBS and RPP/SBS blends was studied. The obtained resuls showed that the addition of both elastomers into recycled polypropylene had a similar effect on modification the RPP properties, but SEBS exhibited a higher increase of elongation at break and IZOD impact than SBS, due to a good compatibility with polymeric matrix.

Abstract: The present paper aims to assess the quality of materials used in the field of removable dentures namely classic acrylate and crosslinked acrylate with improved polymerization using as template vitamin B12 (cyanocobalamin). A major task is the trajectory of Candida albicans biofilm formation and their adherence to the surface of these materials.

Abstract: Present requirements of the modern man impose the realization of textile products with an increased comfort that should provide, besides their basic functions, the conditions of easy motion, aesthetic aspect, easy maintenance etc. These requirements are conferred by the textile products containing elastomer. The development of elastomer fibers and filaments based on polyurethanes, as well as the progress in textile mechanical and chemical technologies, offer the possibility to obtain textile products with increased elasticity. Wool-types yarns with different torsion degree (twist factor 72÷128) and elastomer content between 4.5 and 11.5% have been realized. This work studies the influence of torsion degree and the elastomer content on yarn characteristics.

Abstract: An organic–inorganic conductor’s Polypyrrole(Cl)/Zeolite 4A (PPy(Cl)/Z4A) was successfully synthesized by chemical oxidative polymerization at low and room temperature, using FeCl3 as initiator the reaction and dopant at the same time. After characterization, commodity we methods primarily on the polymerization of pyrrole with different molar ratios of [FeCl3]/[Pyrrole] in an aqueous medium, followed by a series of characterizations for the polymers obtained. The right ratio was used for the preparation of nanocomposites PPy(Cl)/Z4A. After each synthesis, the developed product is characterized by FTIR, SEM-EDX, XRD, electrical conductivity and cyclic voltammetry, in order to confirm the success of the process of synthesis and study their properties to specific applications envisaged.

Abstract: Dental implantology is a frequently applied method for prosthetic restoration of edentulous dental arches. In the past 50 years it has been evolving most dynamically among other branches of dental sciences. According to several reviews and meta-analysis of literature, it seems that the most predictable phase that influences success rate of dental implants is limited only to the surgical stage of treatment [1]. The long term success of dental implants is highly influenced by their biomechanical behaviour, load transfer and osseous tissue reactions to local mechanical tensions around dental implants [1-3]. This in vitro study was aimed to investigate and locate peak tensions inside the fixating substrate of dental implant intimacy. Three root form dental implants were installed, with 14 mm length and 4.5 mm diameter, in tripodistic alignment in a highly rigid and resistant plastic sheet (Araldit-D) also used for photo-elastic measurements. The dental implants were compressed simultaneously and grouped with linear, vertical forces. The mechanical stress distribution and the displacement field of the fixating substrate were analyzed with Digital Image Correlation method (DIC). This modern, non-contact optical investigational method offers highly accurate measurements with great precision (in order of microns, mainly pixel by pixel) practically eliminating all disadvantages and limitations of the most used, classical, experimental methods [4, 5]. Peak tensions were found at the neck area of this type of dental implants. The thickness of the fixating substrate influenced more the appearance of peak tensions rather than the distance between two dental implants. Tripodistic alignment of dental implants might be reconsidered in areas where bone thickness is limited. Virtual, biomechanical simulations should be used in future for surgical treatment planning.

Abstract: The aim of this study was to assess the effect of toothbrushing with toothpastes having different relative dentine abrasivity (RDA) and toothbrushes having different bristles hardness on different composite resins, compomers and traditional glassionomer cements by surface roughness evaluation. All the samples were evaluated regarding the surface roughness using roughness checker (Taylor Hobson-Surtronic25, AMETEK Inc., Pennsylvania, USA) and the average roughness values (Ra) were recorded. In the conditions of this study all the tested materials were abraded by the toothpastes and toothbrushes. Hard bristles tootbrush associated with high RDA tootpaste abraded higher all the materials for filling when compared to hard bristles tootbrush associated with low RDA toothpaste and medium bristles toothbrush associated with low RDA toothpaste. Traditional glassionomer cement was the most affected by abrasion, followed by microhybrid composite resin, flowable composite and compomer.

Abstract: The purpose of this study was to investigate the surface roughness of one restorative composite material when using the Profine System with Lamineers tips. 3 shades of composite resin were used for testing. 15 discs of composite resin were prepared for each shade; 5 discs received no treatment, while the other 10 were divided in two study groups which were polished using either the diamond or the carbide tips using reciprocating movements. The roughness values (Ra; µm) were assessed using a profilometer and the effect of polishing systems on the surface roughness in each group were statistically analyzed. The surfaces of specimens were observed by scanning electron microscopy. The results indicated that the surface roughness depended on type of Lamineer tip and shade of the composite resin.

Abstract: The purpose of this study was to compare the clinical effectiveness and patient compliance regarding interceptive orthodontics, between a prefabricated functional appliance (PFA) and an Andersen Activator.The PFA appliance used was the TRAINER System™, a flexible appliance made of non-thermoplastic silicone (soft) or polyurethane (hard). The Andersen Activator is a functional acrylic appliance.The sample consisted in 20 subjects (10 girls,10 boys), mean age 10.5 years with a class II division 1 malocclusion and an overjet > 6mm. The patients were randomly selected for treatment with either PFA or AA. Overjet, overbite and lip seal were recorded before and every 3 months after the start of the treatment. The treatment was considered finished when the overjet reduced < 3mm. No significant differences were found in overjet and overbite reduction or lip seal between the two groups. The Activator caused less discomfort than the Trainer, and seemed to be more acceptable.

Abstract: The aim of this study was to demonstrate the use of adenosine triphosphate– (ATP–) driven bioluminescence as an innovative tool for the rapid chairside enumeration of oral bacteria (including plaque streptococci) and assessment of oral hygiene and caries risk. The study group included 60 patients with 120 direct coronal restorations with three tipes of restorative materials (resin-modified glass ionomer cement GC Fuji VIII, giomer Beautifill Flow Plus Shofu and composite resin (GC Gradia) from witch we have collected 120 specimens using a luciferase-based assay system(system SURE II). The values of ATP were obtained with System SURE II device and statisticaly analised with Wilcoxon Test. The lowest value was shown for glass ionomer cement GC Fuji VIII, comparing with composite resins, but in time we have seen the increase of ATP for all three restorative materials.

Abstract: The study presents the experience of Medvarix Clinic in treatment of varicous veins using foam sclerotherapy during 2010 – 2015. It is a retrospective study on five years with 893 patients with varicous veins. Mean age – 47years. There were 532 women and 361 men. CEAP classification: CEAP stage III – 279 cases, CEAP stage IV – 246 cases, CEAP stage V – 201 cases, CEAP stage VI – 167 cases. There were 893 ultrasound guided foam sclerotherapy procedures. 261 cases had associated sclerotherapy for perforating veins of closed varicous ulcer and 161cases had associated sclerotherapy for perforating veins for open varicous ulcer. Complications during procedure: misspunction of saphenous vein per primam with a secondary punction – 39 cases, postinjectional hematoma – 11 cases, local allergic reaction – 9 cases. All treated conservatory. Late complications: minor – hiperpigmentation – 47 cases, local inflammations – 101 cases, superficial tromboflebitis – 10 cases, postinjectional necrosis – 9 cases. Major complications: profound tromboflebitis – 1 case. Ultrasound guided foam sclerotherapy is a safe mode to treat varicous veins with good both functional and aesthetic results.

Abstract: The purpose of this study was to evaluate the effects of various acrylic structures anchored in the territory of termopolimerizable acrylates or flexible injection at tissue level. The changes induced at the termopolimerizable Meliodent acrylate type, took into account the diminishing of the fluid content, responsible for inflammatory and allergic reactions, and adding a metacrilat methyl maleic anhydride copolymer (M88). There were clinically evaluated the effects of different acrylic structure at the tissue level as well as for the resistance forces. Very good results in terms of inflammatory reactions prevalence were mild to obtain with flexible acrylate for termopolimerizable acrylate type Vertex without content of Cadmium and acrylate type Meliodent with the lowest fluid content and copolymer added. The optimal results in the plan of reducing the inflammatory effect of the tissue was doubled by biomechanical good results for Acrylates flexible termopolimerizable acrylate type for Vertex, and acrylate type fluid content Meliodent with 13, 72 and added copolymer.

Abstract: An important influence factor is the cooling speed value after the heat treatment. It is important to be chooses the optimal cooling regime because the steel can be laminate at high temperature. Another reason for the monitoring of the cooling speed and the conditions of the cooling regime is the possibility that the steel was heated at high temperature after lamination process, for plastic deformation, to realize metallic sculptures or other components used in industry. For this study we considered three groups of samples of the steel, each group had eight samples. Three different mediums for directing of the cooling process were considered. The characteristics of the plasticity and some mechanical properties of the steel have been modified. Finally, after an experimental program, a statistical model tried to demonstrate that a causal connection between two variables such as: the cooling speed (VR) and tensile elongation (A5) of the samples from steel exists. This work proposes to achieve a statistical model and it studies the possibility to improve the characteristics of the plasticity implicitly other properties of steel used for metal structures.

Abstract: The paper presents the study on the retrieved polyethylene components from total knee prosthesis. For the longevity of total knee arthroplasty it is very important to predict the polyethylene wear and optimize the prosthetic design. The functionality of the total knee prosthesis is affected by contact stress, sliding motion and kinematics of the prosthesis components. The most important factors which cause long-term failure of a prosthetic joint are: macroscopic fracture of the metallic components, polyethylene component wear, corrosion process, and osteolysis. Even the prosthesis development over the past decade has included improvements in implant designs and use of advanced biomaterials, is still difficult to replace some classic biomaterials. Ultra-high molecular-weight polyethylene (UHMWPE) has been the primary material for the articulating surface in prostheses for nearly 40 years. Even now there are a number of problems with the UHMWPE, which cause troubles for the patients. On retrieved polyethylene components, 7 different defects were observed (burnishing, scratching, pitting, surface deformation, delamination, abrasion, bone-cement debris) using stereomicroscopy and scanning electron microscopy. It was found that the cement debris on the surface of the polyethylene explants reduce dramatically the total knee prosthesis lifetime and using FTIR analysis was clearly identified the presence of the cement debris on the surface of polyethylene component. Delamination and abrasion contributed the most to the total amount of damage; according the Hood model, the most damage area of the polyethylene components was seen at the medial (1, 4 sections) and lateral sides (5, 8 sections), followed by the anterior and posterior sides.

Abstract: The surface of any metallic material, is degradating over time from the repeated impact with the microjets and shock waves generated by the bubbles implosion formed during cavitation. Beside the classical methods of heat or thermochemical treatments, several research institutes and hydromechanical equipments users are oriented to the development of metal-ceramic composite coatings deposited by thermal spraying, to provide good protection from corrosive and erosive action of the liquid medium. The researches from this paper analyse the behavior and resistance to erosion cavitation of a Duplex stainless steel whose surface is coated with WC-9Co-5Cr-1Ni powder, deposited by high velocity oxygen fuel (HVOF) spraying method and followed by laser remelting. These investigations, performed in the Cavitation Laboratory of University Politehnica Timisoara, on the vibratory apparatus with standard piezoceramic crystals, outline the need for remelting the sprayed coating in order to improve its adhesion to the substrate and moreover for growing the mechanical impact resistance with the microjets and shock waves developed during cavitation.

Abstract: Clostridium difficile infection (CDI) rates in the United States and the world have increased in the last decade, along with associated morbidity and mortality. CDI symptoms can range from mild diarrhea to severe cases including pseudomembranous colitis and toxic mega colon and death. We performed a retrospective study including 130 patients with multiple organ failure who developed Clostridium difficile infection, admitted to the Iasi Sf. Parascheva Infectious Diseases Hospital in the interval January 1st, 2014 – June 1st, 2016; in order to highlight the high incidence of it and showing how we can manage this situations. An increased number of patients with Clostridium difficile infection and multiple organ dysfunction, in 2015 and 2016 was noticed. The profile of the patient from our study is a female with the age over 65 years old, coming from the rural area. Many of the admitted cases were patients enrolled in Hemodialysis Center. Cardiovascular disease was the most common associated pathology (60.79%), followed by renal failure (42%). Charlson comorbidity index showed 3-4, for 97 cases. The specific antibiotherapy for CDI was administrated for 5-7 days to 21 days long. In 73% of the cases the CDI was treated, 17 cases recorded relapse, and one case died. Clostridium difficile is the most common enteric pathogen in hospitalized patients. Standardized procedures to implement hygienic measures and restricted use of antibiotics are necessary to control the widespread occurrence of CDI in immunocompromised renal patients.

Abstract: Medical devices’ field is developing very fast and the polymers represent next to biocompatible alloys a priority to the research field. The duodenoscopes are intensely used for diagnosis and treatment of various pancreatic and biliary diseases, being in contact with all liquids from saliva, gastric juices and bile liquids. Next to the aggressive environment physical erosion occurs. Using the optical microscopy the superficial polymer coating was analyzed. The deterioration of the coating is increasing the risk of infections and biofilms.

Abstract: The aim of our study was to investigate the root surface after scaling and root planning (SRP) made with Periotor inserts and contra angle handpiece Profin, comparatively with other two very popular SRP techinques: Gracey curette and ultrasonic piezoelectric scaler with perio-tips. A total number of 30 teeth extracted for periodontal causes were used, 10 teeth for each method of scaling. Samples were examined using ESEM and for each sample micrographs were obtained in four magnifications (× 200 × 1000 × 2000 × 5000). Two examiners blinded to the scaling method but previously trained in evaluating the root surface morphology using RSSL index, examined each micrograph and established a RSSL score. It was considered the highest score for each sample and the average scores were calculated for each group. Lowest scores were obtained by scaling with Periotor inserts followed closely by ultrasonic scaling with perio-tips. Use of Gracey’s curettes left the most extensive areas of dentin denudation and in some samples even traces of scratching. In conclusion, our study highlights that using Periotor inserts for root surface scaling the root surface morphology obtained is the most regular and even with fewest dentin denudation areas.