Volume 53, Issue 3

Abstract: Polyester-ether polyols were prepared by a clean method, consisting of PET wastes glycolysis with common diols (diethylene glycol and a mixture diethylene gycol/ dipropylene glycol) and a diol derived from biomass (isosorbide) followed by mono-esterification of the glycolyzed products with phthalic anhydride and subsequent propoxylation, under relatively mild conditions. The polyester-ether polyols were characterized by chemical methods, dynamic viscosity measurements, gas chromatography and 1H-MNR spectroscopy. Experiments, conducted in order to test the polyester-ether polyols in rigid polyurethane (PUR) foams formation, showed that the chemical composition of the experimental polyester-ether polyols is fully suitable for reaction with di-isocyanate. The physico-mechanical and flame retardant properties of PUR foams, prepared by using the experimental polyester-ether polyols up to 30% wt. of the polyol component in the foam formulations, were at least similar to the properties of the foam obtained from PET wastes by classical recycling methods. The synthesis method is in agreement with the principles of clean technologies and green chemistry, in the sense that no by-products and no wastes results.

Abstract: Endoscopic dacryocystorhinostomy (DCR) is a well-established treatment for epiphora caused by anatomic or functional obstruction of the nasolacrimal apparatus. A thorough understanding of the endonasal anatomy, wide marsupialization of the lacrimal sac, and meticulous care for the mucosa are critical for success. Nasal endoscopy has also facilitated the level of performance of the technique. The aim of this paper is to propose a new alternative for the dacryocystorhinostomy (DCR). The use of the new stent with a special design will give the surgeon the ability to keep the stent in the lacrimal duct as long as it is needed.

Abstract: The aim of this study was the encapsulation of ginger essential oil in polymer particles. The chosen method was suspension polymerization of methyl methacrylate. In all cases, the polymerization process in the presence of ginger essential oil leads to decrease of the conversion at similar reaction intervals. The different reactivity of the essential oil components towards the free radicals generated by the thermal decomposition of AIBN was determined using GC/MS headspace analysis. The amount of encapsulated oil was determined by thermogravimetrical and GC analyses. TGA provided less reliable data about the total encapsulated essential oil. However, the extraction and GC analysis of the samples confirmed a higher content of essential oil in sample 2 (0.03 mol/L AIBN), and the lowest in sample 4 (0.09 mol/L AIBN).

Abstract: Utilization of relatively simple devices fitted for the ring frames permits the realization of yarns with filamentary elastomer core. The aspect of yarns is similar with that of the classical yarns, but their structure and characteristics are very different. Depending on the core-sheath combination, filaments and fibers nature and characteristics, the quota of components participation, yarn twisting degree etc., the range of these yarns assortment is practically unlimited. Due to the large capacity of deformation and recovery of the elastomer filaments, the classical methodologies used to determine the classical yarns characteristics cannot be applied to the elastomer-containing yarns, and these yarns show specific indicators for characteristics assessment. This work presents a synthesis of some ample researches on the methods and characteristics of wool-type yarns with elastomer core, as well as the transfer of elastomer filament characteristics to the composite yarns that contain elastomer.

Abstract: When we talk about plastic industry, then one of the most important aspects of this trade is giving the plastic its bright and attractive color. As more and more people crave for the “return to nature” touch, pigments extracted from vegetal materials considered as waste have been analysed for dyeing textiles and manufacturing colorants for painting. Senescent leaves of Vitis vinifera L. have been tested for their capability of extracting organic pigments (chlorophyll, carotenoids, xanthophylls and anthocyans). The results show that the potential exists, further research is needed in order to best develop the methodologies needed.

Abstract: Virtual-patient (VP) software is an innovative educational tool which provides a safe environment in which students and interns can acquire clinical skills before engaging in real patient cases. Virtual patients allow the study of different scenarios regardless of the teaching staff availability, student location or, more important in dentistry, accessibility to patient, dental materials and different technologies. Considering the high standards of nowadays dentistry and, unfortunately, the limited possibilities in university clinics, the young doctors might find themselves in front of an overwhelming dilemma concerning material selection, appropriate technique and technology. The aim was to assess the qualitative general impact of VPs on dentistry students and the qualitative impact of two virtual clinical cases in particular, focusing on the selection of dental materials and on the suitable technology. 73 students participated in this study. The study comprised 5 stages: answer to an initial questionnaire regarding the students’ previous experience with VP software and their expectations related to the VP characteristics; incorporate the results of the initial questionnaire into building the two mentioned virtual cases; use built VPs in student training; answer to a final questionnaire recording the student feed-back to the VPs used; corroborate results from the two questionnaires to establish relevant qualitative features for VPs in dentistry. The results of the study are an important feed-back tool helping in developing and refining VPs with a high degree of acceptance, maximizing the educational efficiency of this learning method. Some of the most desired characteristics were: multimedia content, feed-back for good and bad decisions, low to medium degree of complexity, high coverage of course subjects. The use of VPs offers the chance of working with a broad range of dental materials (in a simulated mode) which is not normally possible in a real practice constrained by financial restrictions.

Abstract: This study analyzed the lead behavior from CRT glass embedded in original composite materials exposed to different pH and temperature conditions. For this study were obtained composite materials with CRT glass (funnel) waste, some of them with zeolite addition, for lead chelating. The experimental results showed the pH and temperature influence lead leachability during the ultrasonic procedure and explained the influence of zeolites in lead behavior.

Abstract: Injected plastic parts with internal threads (round, trapezoidal or saw) can increase products functionality but if not carefully designed can add unforeseen costs into the manufacturing process. In this paper the authors presents a computation methodology of the demolding moment for two cases of plastic injected parts with internal saw thread. This key parameter of the injection process directly influences the design solution of the ejector system. As further work the author will try to validate this method through a set of practical experiments.

Abstract: The paper features several one-dimensional models to represent the rubber springs used in the dynamics simulations for the railway vehicles. Similarly, it includes a description of a model for the illustration of the mechanical behaviour of a mix coil spring - rubber employed in the secondary suspension of the passenger cars. The principle of this model relies on the overlapping of three components – elastic, viscous and the dry friction. The dependence of the force developed in the mix coil spring - rubber on the frequency and amplitude of a harmonic excitation is highlighted via the numerical simulations.

Abstract: In the light of multiple research on dental erosion, by using the spectrophotometry absorption method, we have conducted a in vitro study with the aim to highlight the erosive effect of chlorinated pool water, as well as the protective role of a lacquer and of two different toothpastes with remineralizant effect. Followed targets: the erosive capacity evaluation of three chlorinated waters used for swimming pools, the quantitative determination of the calcium and phosphates concentration absorbed by these waters, the quantitative determination of the remineralization and protection capacity of some dental materials on the enamel exposed to the action of chlorinated waters. After exposing the enamel to the action of these waters, we determined that the swimming pool waters improperly chlorinated represent a risk factor for the performant and casual swimmers. These waters have the capacity to demineralize the dental enamel in vitro, the severity of the demineralization being influenced by the pH and the capacity of extracting different quantities of calcium and phosphates. The three materials used for protection are able to remineralize the dental enamel, the best effect being given by the application of fluorinated lacquers. Optimal maintenance strategies of the swimming pools and specific prophylactic methods for the performant swimmers are necessary.

Abstract: Genu valgum or valgus knee is a disorder caused by the knee deviation in the frontal plane, when the external angle formed between the thigh and calf is less than 170 degrees. The incidence of this disorder is unknown; it can occur sporadically or inside the family and it is one of the most common causes of joint pain. This study describes the properties and the application of a commercial material, AliPlast™ 10, in the case of a 13-year-old patient which presents bilaterally genu valgum deviations. Important improvement in gait and posture were obtained after a 6 months treatment, in which the patient has used the orthoses, combined with physical therapy.

Abstract: The superstructure of dental implants represents the portion that is attached to the implant substructure, by a fixed or movable prosthetic restoration, realized in order to restore the disturbed functions oro-facial system. Recently, a new high performance polymer, BioHPP, based on polyether-ether-ketone (PEEK) polymer was introduced as dental material for manufacturing the superstructure dentures on dental implants. The purpose of this article is to present the results of the clinical trials referring to the advantages of BioHPP polymer as superstructure in oral implantology. The research has been carried out on 35 patients. The recordings of the advantages in the using this polymer for superstructure on dental implants, in accordance with six evaluation criteria, were performed in three dental schools from Romania, monthly, during one year. The results of survey demonstrate that BioHPP polymer as superstructure on dental implants present many advantages, therefore this PEEK type of dental material represents a beneficial new acquisition for patients’ oral health.

Abstract: This study reports the preparation of gelatin – poly(vinyl alcohol) / graphene oxide composites by combining ultrasound treatment, freeze-thawing and freeze drying techniques. Characterization results highlight the positive effect of graphene oxide on materials structure, morphology, swelling degree and biodegradation, as well as rheology.

Abstract: This paper deals with an input oriented method called Ecological Rucksack applied on two materials –corn starch polylactic acid (PLA) granules (bottle grade) and polyethylene terephthalate (PET) granules (bottle grade). We calculated the total mass of material inputs of PLA (from the cradle to the point of sale) and made comparative analysis with PET. Case study results indicate that Ecological Rucksack of PET granules (bottle grade) in terms of its abiotic material and biotic material requirement is about 44% lower than the Ecological Rucksack of corn starch PLA granules (bottle grade).However, PLA has significantly lower water requirement compared to PET. The study has highlighted some limitations of the Ecological Rucksack method arising from the limited data availability and uncertainties associated with its application.

Abstract: The column type reactors play a particularly important role in the chemical industry and technology, because they are successfully used in most of the industrial processes. The inner stirring may be achieved by different mechanical means or by bubbling a gas. This study presents some aspects regarding the heat transfer for a process performed in an experimental bubble gas column reactor. The process in a bubble column reactor was performed at different conditions regarding: temperature, pressure of the inlet gas, nozzle diameters for the inlet gas, packing material inside the reactor; choosing in the end the most convenient conditions for the process energetic consumption efficiency.

Abstract: The aim of this study was to obtain an edible film polymer matrix naturally extracted from tubers of Helianthus tuberosus L and biologically active components extracted from the roasted seeds of Vitis vinifera, in order to protect the active components from oxidation reactions during food conservation. The film was prepared by filling technique. It was evaluated the antioxidant activity of the film by means of DPPH (98.7%) technique, solubility water solubility (20.4%) and Isothermal sorption of water by GAB (Guggenheim, Anderson, de Boer) technique resulting a value of water activity of 0.167 and a value monolayer of 0.026 g water/g film. Through these values the resulting film ensure a sound management of the evolution of biological systems from the point of view of their complexity, especially food whose degradation can impact on their safety.

Abstract: The main goal of this study was to modify halloysite with polyethylene glycol methacrylate and polyethylene glycol dimethacrylate in order to realize some pH sensitive controlled drug delivery systems. The obtained samples were characterized by spectral techniques (FTIR, XPS) and thermal techniques (TGA, DSC). There was also studied the influence of clay type and initial clay amount onto the drug adsorption process within halloysite. The hydrocortisone release profile was also investigated in simulated gastric fluid and simulated intestinal fluid.

Abstract: At global scale, the trend of developing new thermoresistant polymeric structures, obtained from a mixture of dynamically cured elastomer/plastomer, and compatibility and curing agents, broadens their area of application and leads to greening of their processing technology and qualitative performance. Through dynamic curing and compatibilization, the elastomeric particles disperse more readily in the mixture thus making it possible to develop new innovative materials and techniques. Polymer structures were obtained by extrusion granulation technology, tested physico-mechanically (hardness, elasticity, tensile strength) according to current standards and morphologically by electron microscopy (SEM).

Abstract: The aim of this work is to examine the role of alloying elements (Cu, Mg, Zn) in the complex reactions occurring in the heterogeneous system Al-Cu-Mg-Zn/K2TiF6/KBF4 at high temperatures. The paper presents theoretical and experimental studies to obtain aluminothermic reactions of composite AA7xxx/TiB2, putting into evidence the thermodynamic calculations and X-ray diffraction resulting compounds.

Abstract: Batch adsorption of 4-nitrophenol (4-NP) from aqueous solutions on some non-ionic porous copolymers based on the styrene and divinylbenzene was investigated. The adsorption studies were performed as a function of various parameters: contact time, initial concentration of 4-NP solution and adsorbent/adsorbate ratio. Equilibrium and kinetics studies were investigated. Also, from the adsorption data the specific surface area of the polymeric adsorbents has been determined. The results showed that the porous beads prepared in presence of porogen mixture (toluene:gasoline) could have potential applications in the treatment of environmental pollution caused by 4-NP.

Abstract: The poly(betaines) have been still intensively studied due to them biomedical potential. In the present work, two poly(carboxybetaines) derived from poly(4-vinylpyridine) P4VP that have methylene (P4VPB-1) or ethylene (P4VPB-2) spacer between N+ and COO- groups were investigated in order to evaluate its physico-chemical properties in aqueous salted solutions with NaCl or CaCl2. The values of refractive index increment dn/dc, weight-average molecular weight Mw, hydrodynamic radius Rh, and particle size distribution depend on the solvent type and balance between molecular forces as refractometric and laser light scattering measurements showed.

Abstract: Aeronautic industry is on the trend of development and more comforts are being incorporated in the aircrafts. On the other hand it is necessary to achieve stringent demand of fuel economy and high performance at low cost. To achieve high fuel economy the aeronautics manufacturers are induced to reduce weight in the possible fields. Light weight composite materials like carbon fiber for the impeller of aerodynamic compressors have been used to achieve the requirements of the aeronautics industry. The paper is focused on the FEM modeling and experimental determination of the two tests of the composite material characteristics used for the impeller of aerodynamic compressors.

Abstract: Rapid heat cycle molding (RHCM) is a special molding process capable of producing molded plastic parts with high surface quality and improved weldline strength and appearance. This study investigated the influence of the weldline on the tensile strength of RHCM and conventional injection molded (CIM) components. The test specimens with and without a weldline were cut from RHCM and CIM parts for scanning electron microscopy (SEM) imaging to characterize the structure and dimensions of the weldline and tensile testing. The tensile testing results showed that the weldline reduced the tensile strength, but RHCM decreased the tensile strength reduction effect of the weldline. There was no distinguishable difference between the two molding processes for the tensile strength of specimens without a weldline. In addition, a thin surface layer of material containing the V-notch at the weldline was removed from the RHCM and CIM parts to examine its effect on the tensile properties. The thinned-out specimens with a weldline showed improved tensile strength, and specimens without a weldline showed decreased tensile strength, compared to specimens with the original full thickness.

Abstract: Closed cell polyurethane foams with densities of 100, 140 and 325 kg/m3 were tested in compression at speeds from 0.6 to 500 mm/min. Digital image correlation (DIC) is used to determine the engineering characteristic curve, modulus of elasticity, maximum stress, and the deformation bands that appear during deformation and prior to the final failure of the specimens. By using this procedure both global and local phenomena are observed and analyzed. While each specimen is compressed, the damage behaviour of the foams is directly observed in different stages.

Abstract: In the first part of the paper we touch on the influence of the processing temperature by injection of HDPE, of PMMA, and of PC+ABS blend on some mechanical flexural properties, while the other factors which could influence the injection remain unchanged. In the second part of the paper, we present the influence of the subsequent pressure in the injection of HDPE, PMMA, and PC+ABS blend on mechanical bending properties, while the other factors which could influence the injection 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, 900, 1000, 1100 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 bar, 800 bar, and 900 bar. We have used the method of determining flexural properties, such as the flexural stress, flexural deformation, and flexural modulus. It was observed that in the case of HDPE, the highest values of flexural stress were registered at its lowest temperature (180°C) – the flexural stress recorded 28,3038 MPa – and at the highest value of subsequent pressure (1200 bar) – the flexural stress recorded 29.3380 MPa. PC+ABS acts in a similar manner to HDPE. In the case of PC+ABS, 240°C recorded the highest value for the flexural stress of 89.2246 MPa, while the highest subsequent pressure of 900 bar recorded the highest value of flexural stress of 88.5375 MPa. In the case of PMMA, the highest value for flexural stress (124.2563 MPa) was recorded at the lowest processing temperature (220°C) and at the subsequent pressure of 550 bar, where the value of the flexural stress was of 110.5376 MPa. In the case of HDPE and PC+ABS, the flexural deformation is barely influenced by the processing temperature and the subsequent pressure, whereas in the case of the PMMA, the processing temperature and the subsequent pressure influence the flexural deformation. The increase in the subsequent pressure leads to a slight increase of the flexural modulus in the case of the three studied polymers. The increase in the processing temperatures of HDPE and PC+ABS leads to a slight decrease of the flexural modulus, whereas in the case of the PMMA, the increase in the processing temperatures barely influences the flexural stress.

Abstract: In space filed usually size doesn’t matter but weight does, being a critical point in space structure design stage. Carbon fiber reinforced polymer composite materials are already deployed in many space applications, due to their intrinsic characteristics, mainly their high strength/high stiffness to weight ratio and potential for zero or near-zero CTE, coefficient of thermal expansion. The paper presents the results of the study made on advanced composite exposed to extreme conditions comparable to those found on space environment (Low Earth Orbit – LEO [2000 km). The samples were manufactured from CFRP epoxy composite with different thicknesses (1.2 mm, 1.8 mm, 3.7 mm, 7.7 mm) using autoclave technology. The 1.8 mm thickness samples were coated with 50 and respectively 100 µm of Zn using arc thermal spray technique. Specimens were exposed to UV, gamma radiation and thermal cycles. The results of microstructural, morphological analysis and mechanical characterization showed the aging and damage mechanisms developed post exposure in comparison with reference materials.

Abstract: The present paper aims to examine the way in which the temperature is distributed when the polyethylene sockets are welded using the electrofusion procedure. This research is necessary because in practice certain problems occur relating to the destruction of these sockets during welding or later. The survey is conducted in cooperation with companies working in the field of welding in polyethylene, complying with the required standing standards.

Abstract: A series of bismaleimide monomers and polyaspartimides with various structures were synthesized and their structures were confirmed by Fourier transform infrared (FTIR) and proton nuclear resonance (1H-NMR) spectroscopy. Chain extension of bismaleimides was accomplished by incorporating various ether or other groups. Polymers based on these bismaleimides were prepared by the Michael addition of diamines with various structures to bismaleimides. Thermal and dielectric properties of these polymers were studied.

Abstract: adhesives over acrylic classic prosthesis, but the literature lacks in comparative studies that investigate the effects and advantages of denture adhesives on obturator prosthesis performance. The hypothesis for this study was that the use of the denture adhesive would improve both wearing and efficiency on obturator prosthesis. We evaluated the clinical behaviour of six acrylic obturator prosthesis made on various maxillary defects, with and without a denture adhesive. The adhesive was applied on the prosthesis as recommended by the manufacturers. Patients used the adhesive for 24 hours and, through a questionnaire, they evaluated (comparative with and without adhesive) There are many studies in the literature regarding the effect of denture the following aspects: prosthesis retention, duration of retention, masticatory efficacy, cleansing of dentures, cleansing of gums. The clinical retention of the dentures was correlated to Modified Kapur Index Scale (MKIS) for denture supporting tissues.

Abstract: The aim of this study was to asses the flexural strength of provisional acrylic resin fixed partial dentures reinforced with glass fiber with the provisional restorations without reinforcement. Three group of specimens were prepared for the flexural strength: Poly Methyl Metacrylate (PMMA) acrylic resin provisional restoration without glass fiber (control), acrylic resin provisional restoration reinforced with glass fiber between the abutments and acrylic resin provisional restoration reinforced with glass fiber including the abutment and the pontic of the fixed partial denture. The flexural strength was tested with a servo-hydraulic testing machine (Zwick Proline Z005 device), with a maximum 5KN force The highest resistance to deformation and fracture was registered in acrylic resin provisional restoration reinforced with glass fiber including the abutments.

Abstract: In present paper there are given the results concerning wear behaviour in Ringer’s solution of four titanium alloys with 5%Mo, 7%Mo, 11%Mo and 12%Mo. Structural investigations (made by both optic, electronic microscopy and X-Rays diffraction) revealed a dual phase structure consisting from alpha martensite and beta”solid solution, with the constituents proportion depending on molybdenum content. Wear rates were determined using a Talysurf profilometer in Ringer’s solution for the experimental titanium-molybdenum alloys. Finally, the beneficial influence of molybdenum on wear behavior was put in evidence: the higher molybdenum content is, the lower friction coefficient is.

Abstract: A novel assay for the electrochemical detection of 4-nonylphenol (4-NP) based on carbon nanotubes modified screen-printed carbon electrodes (CNTs-SPCEs) has been investigated. The electrochemical behavior of the modified SPCEs and the mechanism of the oxidation of NP were investigated using cyclic voltammetry. The differential pulse voltammetry parameters were optimized for quantitative determination of 4-nonylphenol. A detection limit of 9.95·10-6 mol·L-1 was obtained for 4-nonylphenol using its oxidation signal at +0.25 V. The disposable sensor showed good performance and was applied for the determination of 4-nonylphenol in tap water with satisfactory results.

Abstract: The obtaining of polymers with special properties is dependent on both conditions and materials used in the formation process. This work presents the obtaining, by using the sol-gel method (and citric acid used as in mixture fuel), of some powdery materials destined to be used as additives in polymers’ formation. Different types of salts were used in the powders’ obtaining process, the long term purpose being to add special properties to polymeric materials, such as good electrical conductivity or photovoltaic capabilities. The materials and methods are thoroughly presented, proving the obtaining repeatability of these powders. Different characterization techniques were used and presented in this paper, from Scanning Electron Microscopy (SEM) for morphology, to EDX for elemental composition, Raman scattering for vibrational properties, thermal analysis by differential scanning calorimetry (DSC), and electrical resistivity for electrical conductivity calculation.

Abstract: Surgical sutures properly conducted will ensure maintaining the edges of the flaps until the wound healing process allows withstanding the functional stress. Among the possible complications of surgical sutures, we can find the wound suppuration, as a result of contamination with germs. In our in vitro study about the degree of bacterial adherence to different types of suture materials we chose four types of suture materials (three absorbable and one nonabsorbable) exposed to 4 bacterial species (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa). The monofilament absorbable polydioxanone wire had the lowest bacterial adherence, followed by the multifilament nonabsorbable wire of silk and the two types of multifilament absorbable polyglycolic acid wires. Regarding the bacterial species tested, Enterococcus faecalis had the highest adhesion level, no matter what type of material or time of exposure has been used.

Abstract: Because the petroleum based products have a negative impact on the environment,is necessary to create and use eco-friendly lubricants. Vegetable oils are part of this category because they are a renewable natural resource, environmental safety, and show lubricating characteristics. By mixing the castor oil with two synthetic diesters (isodecyl and 2-[(p-nonyl)phenoxy]ethyl adipate respectively, isotridecyl and 2-[(p-nonyl)phenoxy]ethyl adipate) were obtained two series of new lubricants to which the physico-chemical and rheological characteristics were studied. The lubricants were also characterized using the differential scanning calorimetry (DSC) and thermal gravimetric (TG) analyses. The obtained mixtures present superior properties to mineral oils and can be used as lubricants.

Abstract: Ferrites are generally used to obtain soft magnets for domestic or industrial applications but their use in this direction had generated an increasing interest in modifying the polymer properties by dispersing in their volume certain amounts of these ceramic compounds. Of course one issue of each researcher is to find a way or a technique to orientate the ferrites particles inside the polymer matrix to obtain structures able to respond to application of an external magnetic field. The use of ferrites nano-sized particles is facilitating their uniform distribution inside the polymer and, because of the viscous properties of pre-polymer mixture, is avoiding their aggregation. One way to create oriented distributions of the nano-particles is to use external magnetic fields during polymerization such as, at the end of process, they will be kept in fixed position inside the polymer network. The current study is about electrical properties induced by the presence of nano-sized strontium ferrite and barium ferrite in an epoxy matrix. Three types of epoxy resins had been used with 5% weight ratio of each type of ferrite and 10% weight ratio when both ferrites were used to modify the properties of the same polymer matrix. Electric conductivity had been studied by two methods – one on steady-state regime and one in variable regime. Using the variable measurement of electromagnetic properties the dielectric permittivity and the magnetic permeability were also determined.

Abstract: The paper represents a third part from the series, and refers to the elaboration of the experimental protocol regarding the use of Iosipescu test in the optimization of the structural-constructive characteristics of the matrix biomaterials for removable prosthetic restoration. The way the samples were consolidated with aluminum plates, at the clamping ends, was established through traction and shearing tests. Based on the theoretical protocol, the following were determined: the shape, size and loading of the Iosipescu sample, alongside with the bridge calibration. The gathered experimental data were used to evaluate the behavior of the CT-1 silicon adhesive. The paper focuses on the design of the samples used for the traction and shearing tests, made out of biocompatible polymer composite materials .Their structural and feasible behavior is influenced by the adhesion between layers, and by the gluing capacity of the used adhesive. The purpose of the paper is to enhance the performance of polymer composite materials, by using a compatible adhesive in creating a finite modeling element for standard single traction and shearing resistance tests. A tridimensional model of a longitudinal sample that underwent stretching and shearing test, while applying quasi centric loads, was elaborated and the main characteristics of the adhesive and of the glued interfacial area, that influence the structural and functional performance, were analyzed.

Abstract: Morphological restoration of the face in complex tissue defects involving midface remains a great challenge for any surgeon. Tridimensional tomographic analyze gives excellent quality images of the defect and modern technology can provide prosthesis for skeletal replacement at least. Prelaminated free flaps are a method to reestablish morphological aspect and restore lost functions. We describe here a case of 30 years old male patient, victim of a self-inflicted gunshot wound, with a complex defect of the midface. A three-dimensional skull reconstruction was performed in order to restore the midface morphology. Following an initial uneventful evolution, at 2 weeks we noticed partial flap necrosis, with a small island of implant denudation in the mouth and significant decrease of the hypodermis, but with the integrity of the skin covering the implant. Despite of this, we observed a good general condition and improvement of patient’s mental health, swallowing restoration and phonation improvement.

Abstract: Alopecia areata is the most important inflammatory alopecia, caused by immunological factors, genetic factors, emotional factors, endocrine dysfunctions, infectious foci, nutritional deficiencies, and the harmful action of various environmental stimuli. The use of aggressive shampoos, of inadequate cosmetic and styling products, hair dyeing and waving, external pollutants might participate in the physiopathology of alopecia by sustaining inflammation, disturbing the local microcirculation, promoting oxidative stress. The aim of this study is to verify the hypothesis that oxidative stress might influence the progression of alopecia areata. Regulating the possible identified imbalances in alopecia areata might represent a means of preventing or improving this disorder.

Abstract: The present article is the first in a series of three articles presenting results obtained by our team in a study on sandwich composite materials. The aim was to study the damping capacity of some sandwich structures used for a structural element of a machine tool that was reduced to scale (namely, a column), as well as all aspects of the material’s recyclability. The first stage of the study involved the characterization of the Polypad® composite material by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX), Fourier transform infrared spectrometry (FTIR) and X-ray diffraction (XRD).

Abstract: Using special materials with a reverse geometry for contact lenses is named orthokeratology. It is a non-surgical modern medical alternative to conventional contact lenses for correction of myopia. Orthokeratology is an alternative treatment for patients with progressive myopia, especially children. The contact lenses is using during the night for minimum 6 h. With these special contact lenses children can be treated after 18 years old with refractive corneal surgery. The materials of night contact lens are gas permeable and permit progressive aplanation of central cornea, which induced decreasing of myopia or myopic astigmatism. The purpose for this study is to prove the effectiveness in improving of the quality of vision using night contact lens. The study also monitored the effectiveness of orthokerathology as a preventive method for amblyopia in myopic or astigmatic patients.

Abstract: As a result of the requirement to achieve the implementation of the European Water Framework Directive (WFD) in all the member states by 2015, Romanian’s water management policies need to carefully look and consider water quality issues. All waters will achieve a good ecological status, therefore simulation of the existing status of the water bodies and analysis of proper adaptation measures for improving water quality is an important part of the implementation process. Water quality models play an essential role in support of the water management decisions. Present paper presents an application of the DHI tool, Mike 11, for the simulation of water quantity and quality of Bega River. The evolution of a pollutant source is traced both in time and space on a segment of the Bega River, from Topolovat to Otelec. The obtained results show that model is able to capture the water quality of the river, as per the observed values, and it is possible to be used in the future to predict the impact of a certain pollutant on the Bega River. The results of this study show the possibility to develop what-if analyses, which can help decision makers to choose the best adaptation strategy.

Abstract: Bone regeneration remains an important challenge for research trends in dentistry. In this study, the authors analyse the effect of the membrane composition for the results of bone grafting.They used in 30 cases, collagen and polytetrafluoroethylene membranes. The dehiscences was bigger in case with PTFE membranes.

Abstract: Banat River Area specific climate is characterized by moderate temperature and high precipitation amounts, which affect the surface water quality. Since Secu Lake, located on Valley Bârzava provides drinking water to Reºiþa city, the raw water turbidity variation was analyzed depending on changes in climatic parameters. The study is based on monitored values of this quality indicator, within two years (December 2008-December 2010). Deviations from normal climatic limits are frequently caused by CO2 concentration increasing in the atmosphere and massive deforestation determined during the analyzed period, increases in rainfall, with influences on the Lake Secu water turbidity. On the other hand, the works on the Bârzava River course, have contributed to changes in turbidity, by dislodging sand, gravel and various residues. Analysis of this indicator was performed in order to assess the water quality and the necessity of drinking water correction.

Abstract: This study aim to compare the root surface morphology after scaling with Gracey’s curette, ultrasonic tip, Periotor insert, using Atomic Force Microscopy (AFM). For every tooth have been analysed three different zones on the surface and for every zone we investigated concentric foursquare areas with the size of 0.5 / 1 / 2 / 5 / 10 / 20 mm. For every area, bi-dimensional-2D and three-dimensional-3D images, phase contrast and statistical parameters have been registered. Both ways to analyse data: directly, by the images comparing and the statistics revealed a more appropriate surface morphology obtained after scaling with Periotor inserts, followed by Gracey’s curette and ultrasonic tip, which were approximately simillar in features. Acknowledgment: this study was made within UMF-Iasi Internal Grant 30879/30.12.2014.

Abstract: Stem cells are nowadays isolated from multiple sources and used in biotechnological application. Our study presents a new method for isolation and expansion of stem cells derived from infrapatellar fat pad (IPFP) by simple adherence to plastic surface of culture flasks. This method yielded adipose-derived stromal cells (ASC) with morphological and phenotypical characteristics of mesenchymal stem cells, without using any enzymatic digestion, making these cells more suitable for medical application, in treatment of different human pathologies.

Abstract: In order to find alternative solutions for protection of hydraulic turbine components against cavitation, a fluid elastomer layer, curing at room temperature, was deposited onto a martensitic stainless steel substrate. The resistance of the coating to cavitation erosion was determined by the vibratory indirect method, using ultrasonic equipment with piezoelectric converter and the microstructure of the polymer was investigated using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The authors compared the cavitation erosion resistance of the elastomer layer with that of the base material (martensitic stainless steel) as well as that of protective cold hardening austenitic stainless steel coatings, deposited by overlay welding onto the base material. The experimental results revealed that the elastomer coating ensures better resistance to cavitation erosion than both stainless steel types.

Abstract: Biomaterials for bone regeneration techniques can preface rehabilitation implantation, may intervene in the same step with the implantation, or they can find the insertion in reconstructive periodontal therapy. This study aimed to quantify the contribution that different materials may bring for bone regeneration potential in gum regeneration in resizing bone structures affected, in order to establish oral rehabilitation.There were considered a total of five bone regeneration materials(Hidroxiapatite, Bio-Oss, OsteoGraf /N, Osteogen, Cerasorb ), applied in similar clinical situations, radiological assessment of bone regeneration issues, made before the application, immediately after application and 6 months after application. Regarding the quality of bone neo formation, the bone structure was very dense when using Bio-oss and Cerasorb, relevant issues the X-ray that provides the necessary information. In terms of clinical results, they were very good for the other three biomaterials used for bone regeneration. When used properly, biomaterials for bone regeneration provide very good results in terms of maintaining bone volume to withstand the demands, offering also a high percentage of vitality, safety and lack of complications.

Abstract: Since its discovery, more than eight decades ago, the epoxy resin grew quickly to be largely used in all-day activities around the world. This paper presents the evolution of utilization of the epoxy resin around the world, since its discovery until our times. Also, being such a familiar material in all industries, an analyses of its impact on the economy is also addressed in the second part of this study, revealing its importance on the economy of the countries on the both sides of the Atlantic Ocean. The research involving the utilization of the epoxy resin is still underway at this time, an interesting path being taken in Romania at the Research and Development Center for Thermoset Matrix Composites that is part of the “Dunãrea de Jos” University of Galati. Some of the ideas, already partially put in practice are presented in the last part of this article, the utilization of this resin as part of a composite being the main focus of obtaining some materials needed in green-energy production.