Volume 55, Issue 4

Abstract: This research focuses on the analysis of acacia wood reinforced PLA/PHA blend composites. Acacia wood was processed into small chip particles, which were mixed with pure PLA, pure PHA and PLA/PHA blend. The wood was treated using acetic acid and sodium bicarbonate. It was then compressed into sheet film. The micrograph shows that the PLA and PHA mixture create an interlocking continuous structure and the addition of wood strengthens interlocking between PLA and PHA. Mixtures of this blend also reduce bubble and crack, and create new properties superior than the earlier properties of existing PHA and PLA.

Abstract: This work deals with the problem of developing vibration damping polymeric materials which are effective at low temperatures (from minus 40 to 0°C). Due to the fact that the vibration damping efficiency in the composite is mainly determined by the properties of the polymer matrix, it is necessary to study its properties depending on the type and amount of structure-forming parameters. The purpose of the work is to determine the changes in the dynamic properties of the polymer composition based on butyl rubber, EPDM, ethylene-vinyl acetate copolymer (EVA) filled with increasing amount of calcium carbonate. The leading methods of studying this problem were the method of scanning electron microscopy and the method of dynamic mechanical analysis. It has been stated that the selected polymers can be considered as competent candidates for damping materials at low temperatures, and the calcium carbonate filler allows more fully to realize the vibration damping properties of the polymer. The obtained dependences can be used as initial data for analytical predicting of damping properties of polymer composites.

Abstract: The three-dimensional printing is a manufacturing method involving the addition of materials by using certain principles valid in printing techniques. There are various techniques of a three-dimensional printing method and the most of them could be applied inclusively to generate objects of polymers. The objective of the research presented in this paper was to analyze the capabilities of 3D printing process or equipment of generating fine details and to identify a way of evaluating these capabilities when using polyester PLA as filament material. The systemic analysis of the printing techniques which use a fused polymer filament deposition showed that there are some groups of factors able to affect the obtaining of fine details. An experimental research was designed in order to highlight the influence exerted by the diameter of the nozzle orifice and by the values of sharp angles of isosceles triangles on the heights of these triangles, thus obtaining an image concerning the possibilities of generating sharp edges by three-dimensional printing. To evaluate the capacity of the 3D printing process of obtaining thin walls, a spiral including linear segments with a decreasing thickness from 1 mm was also achieved on the test piece. By mathematical processing of the experimental results using a specialized software, empirical mathematical models were determined to evaluate the intensity of influences exerted by the two process input factors on the heights corresponding to isosceles triangles characterized by sharp angles.

Abstract: The main factors that affect the strength of adhesive joints are the exposure to moist environments and high and/or low temperatures. The objective of this paper is to measure the water diffusion in adhesives modified with thermally expandable particles (TEPs) and assess the joint strength of water saturated modified adhesives. Bulk specimens were used to measure the diffusion coefficient of water in a TEPs-modified adhesive. The tensile data as a function of TEPs content, moisture uptake and temperature was measured. It was found that the presence of moisture and the temperature affect the mechanical properties of TEPs-modified adhesive. Further, a scanning electron microscope (SEM) analysis was performed in order to examine the fracture surfaces of the tensile specimens tested as a function of temperature and water uptake. SEM analysis showed that the absorbed moisture and temperature change the fracture mechanisms and the morphology of the specimens.

Abstract: In this study, capillary rheological tests were performed on polypropylene filled with multi-walled carbon nanotubes (PP/MWCNT) to determine the melt flow curves and pressure-Volume-Temperature (pVT) diagrams. Based on the experimental data, master viscosity curves were constructed using the time-temperature-superposition principle and the Cross and Carreau-Winter models, while the pVT data were fitted to the Tait equation in both liquid and solid states. Results show that the melt shear viscosity decreases with increasing melt temperature and shear rate and increases with MWCNT wt.%. All composites display shear-thinning behavior in the range of medium to high shear rates. The specific volume of PP/MWCNT composite decreases with increasing MWCNT wt.% and pressure and increases with increasing temperature.

Abstract: The aim of this study is proposing a combination of measurements to assess the functional variability of collagen membranes used in Guided Bone Regeneration (GBR) and Guided Tissue Regeneration (GTR) techniques. As far as clinical applications are concerned, a proper qualification is critical when deciding, among commercially available collagen membranes, upon the most appropriate one for each specific clinical case. Two commercially available collagen membranes, namely Collprotect® and Jason®, were considered for the experimentation. After thickness and density measurements, the quasi-static behavior was studied for both membranes by means of conventional mechanical tests, i.e. tear and tensile tests, whereas their time-dependent behavior was evaluated by means of stress relaxation tests and dynamic mechanical analysis. Collagen membranes showed an elevated among samples variability. The variability within the same kind of membrane is of the same order of magnitude of the between membrane kinds variability. All the membranes showed strong time dependence both in stress relaxation and in dynamic mechanical tests. This fact should be taken under consideration for the membrane final application.

Abstract: Shape Memory Polymer Composites (SMPCs) are a class of smart materials in which the structural properties of long-fiber polymer-matrix composites and the functional behavior of Shape Memory Polymers (SMP) are combined together. In this study, the frozen stresses resulting from fixing a deformed shape have been investigated. Two different samples were manufactured, with and without significant shape memory properties, and a three point flexural test equipment was used in order to fix a deformed shape. The forces and the resulting stresses were measured during the samples deformation and after the shape freezing. The experimental tests have shown that the shape memory sample has a better ability to fix a deformed shape, since its frozen stress is higher in all the tests.

Abstract: Biodegradable polymers became one of the most important materials with large applicability, as they do not generate wastes after life cycle. An important application is food packaging fabricated by injection molding processing. In this paper, we present the investigation of the mechanical properties of some biodegradable polymers based on PLA composites obtained by melting processing and their morphology studied by SEM analyses, in comparison to polypropylene and neat PLA. We found out that tensile strength, elongation at break and Young modulus exhibit values appropriate to injection molding processing and they are very close related to crystalline or amorphous character of the materials.

Abstract: Surface chemistry and micro-nanoscale topography of biomaterials can significantly influence tissue engineering and cell biology. In this study, polystyrene (PS) Petri dishes were subjected to microtexturing by compression molding process, which resulted in three-dimensional (3D) microscale surface topographies. Three different micropatterned surfaces were fabricated using bronze sintered molds with different mean pore pitch sizes. The surface changes and the morphological aspects were analyzed by 3D surface analyzer. The dishes were then used to investigate the cell behavior of Mouse Embryonic Fibroblasts (MEF) P4 cells. The surface micropatterning have affected in different ways the MEF cell adhesion and proliferation, related to the morphological changes in comparison with unmodified PS. At the increasing of the sintered particle dimensions of the mold, the cavities dimensions on the molded Petri increase and also the cells adhesion in the cavities seems to increase independently from the roughness inside them.

Abstract: Polypropylene (PP) and polyamide (PA) polymers are used in different situations where they provide a flame retarding effect to meet safety standards. The expandable graphite as an additive for polymer materials has a good flame retardant effect and it does not harm the environment. The processing of this additive is presented for those two different polymers. Compounds with proportions of 10, 20, 30% of this additive were prepared in order to investigate the processability and flame retarding effect of PP and PA samples. The results show that the process conditions differ greatly between the polymers used in higher proportions. The improvement of the flame retarding effect was observed for both polymer compounds with expandable graphite. The plastics flammability standard UL 94 V0 could be achieved for the PP compound in all additive proportions and for the PA compounds only above 20%. The processing of the PP compound with co-rotating twin-screw extruder and an injection moulding machine takes place works well and provides a good homogenous mixture. The PA compound could not be processed at a higher additive content by the extruder. Special screw configuration is necessary to process this polymer compound. Also the flame retardant effect was inferior to the PP compound. The mechanical properties of the compounds decrease with the increasing additive content, particularly the impact strength of the samples.

Abstract: In the present paper the authors study the pertraction of the nitrophenols through the immobilization using chemical reaction in receiving phase, using a laboratory installation conceived by the Group of Membranes, Materials and Membrane Processes within University Politehnica of Bucharest. This installation was developed using liquid synthetically solutions, through composite membranes having a matrix of capillary polypropylene and inclusions of ethylene propylene diene terpolymer sulfonic acid (S-EPDM) or sulfonated ethylene-propylene-diene terpolymer (S-EPDM). The results were follow: The permeation through the compartments of the system with composite S-EPDM membranes is limited, in the aqueous phases, by the solubility of the compound about to be separated, namely the membrane itself, and subsequently by its diffusion from the feed compartment to the collection compartment. The chemical reaction of immobilization, in the receiving phase, can be achieved in several variants (neutralization, esterification, complexation, oxidation, coupling, oxidative degradation); The biggest flows are obtained in compensation of the o-nitrophenol with ferric ions and then, in acetylation of the o-nitrophenol with acetic anhydride. However, we can emphasize that the derivatization of the o-nitrophenol through complexation and acetylation reactions requires its use as such in later processes, unlike the neutralization, for which the nitrophenolate ion easily frees the nitrophenol for future applications;For the neutralization reaction, the removing coefficient grows with decreasing of pKa value of the nitrophenols. For complexation reaction, the most favorable results were obtained for o-nitrophenol - over 66%;The coupling reaction of the o-nitrophenol, in the receiving phase, with the diazonium chloride of the p-nitroaniline and hydrogen peroxide 3% in sulfuric acid 20%, respectively, concludes with the exhaustion of the source phase, after 24 hours of operation.

Abstract: Various applications in industry and medicine require the transmission of movement using systems that do not influence magnetic or electromagnetic fields. These components include systems which transmit linear or rotational motion, change position (switches), attach or detach to objects (latches), grip objects, etc. This paper looks into the possibility of producing such mechanisms using FDM 3D-printed parts from thermoplastic materials with embedded moving parts, which can be pneumatically actuated. In order to make the parts suitable for use in pressurized air systems, different sets of printing parameters have been investigated. PLA annealing is used in the attempt to minimize play and increase air-tightness of 3D-printed parts.

Abstract: While over the past century fairly extensive work has been carried out on explosively-driven metallic envelope fragmentation, as the development of explosive materials and warhead configurations continued, the issue under consideration is still topical. The current paper aims to investigate the fragmentation characteristics of explosively-driven steel cylinders when double layer envelopes are used. Mott’s approach was modified in order to account for such particular configuration (layered envelope). Several tests in a simplified type procedure were performed aiming to confirm the theoretical approach.

Abstract: This study presents research regarding the calculation of the mechanical characteristics of composite polymeric materials. By using LabVIEW’ software a virtual instrument was created used for monitoring in real time the process of cross-linking the composite polymeric materials. The experiments were realized based on composite materials containing epoxy/fiberglass resin of different topologies. By means of the virtual instrument and of a sensor created based on the mechanical impedance analysis, implanted in the composite material, it was determined the G shearing module of the composite material at different temperatures.

Abstract: In order to identify the premature biodegradation causes of paint applied in 2013 on a railway bridge, top coat layers applied have been investigated by XRF and SEM-EDAX techniques after 32 years, corresponding to periods of operation under identical climatic conditions of 4.5 years and 3.5 years respectively. By analysis of the experimental results obtained, it has been found that by using suitable painting materials (titanium content of about 7.5 % - TiO2 for UV protection) an exploitation period of more than 30 years could be obtained. Low-carbon (low polymer) and titanium dyeing materials with significant content of soluble salts have a low durability and anticorrosive protection capability. They degrade relatively fast both by top coat degradation and by intense increases of biofouling.

Abstract: The paper deals with some aspects regarding the behavior of modern and efficient solutions - for rehabilitation of reinforced concrete framed structures. The paper is devoted to experimental studies on carbon fiber reinforced polymer (CFRP) systems used as strengthening solution for reinforced concrete (RC) frames assumed as existing structures, which were tested as un-strengthened and as (CFRP) strengthened structures. Single span and single story frames (scale 1:2) were designed and detailed according to the Romanian design codes from 1970s under which seismic design was inadequate. The RC design and the magnitude of applied forces were ensuring the failure mechanism, of non-strengthened RC frames, by plastic hinges at columns ends. Then the columns were strengthened by using CFRP materials. The experimental program emphasized some important aspects regarding the behavior and failure by debonding of CFRP strengthening materials applied to RC frames. The analysis of experimental data and theoretical values showed up an increase of resistance and stiffness achieved by strengthening.

Abstract: The aim of the study was to evaluate and to compare the interface and marginal leakage of dental composite resins using confocal laser scanning biological microscopy (CM). Ten class II cavities were prepared on the proximal surfaces of 10 extracted teeth, previously kept in 10% formalin to preserve the bonding properties of the tooth structures. Cavities were restored with dental composite resin using the ‘open sandwich’ technique and then assessed using CM. Open marginal adaptations at the interfaces inside the composite resins were identified. The results obtained with CM helped to eliminate and reduce the background information collected from a distance from the focal plane and allowed for the acquisition of serial optical sections from thick tooth specimens. In vitro assessments were thus made using CM on the teeth structure, regarding the occurrence of potential micro-leakages at the restoration interface.

Abstract: The Czech Armed Forces´ soldiers of all specializations and mainly the chemical corps´specialist are prepared for task fulfillment in military and non-military operations within those a real threat of weapons of mass destruction employment and, occasionally, the real danger of toxic industrial materials leakage is present. They can solve problems caused by acids leakage in contaminated areas mainly during task fulfillment in non-military operations on the Czech Republic territory in cooperation with Fire Rescue Brigades´ chemical specialists. Individual protective equipment which is established in the Czech Armed Forces were neither design for this purpose and, moreover, nor tested and thus there is no real data concerning their chemical resistivity. In recent time, some methods have been introduced into the Czech Armed Forces environment. They are useful for determination of chemical resistivity of barrier materials against toxic compounds detectable with acid-basic (colorimetric) methods and conductometric ones. The paper deals with the possibility of using the presented methods and compares the suitability of their application in relation to the protective garments designated for the Czech Armed Forces members´ body surface.

Abstract: Novel materials belonging to the class of anionic clays are synthesized by investigating their properties at nano scale. Thus, hydrotalcites or layered double hydroxides (LDHs) were used as drug delivery carriers in order to prevent or to treat infections produced by some pathogen agents. Their physical and chemical properties allow them to include different molecules in the interlayer space and then to ensure their transport to the target. The current work reveals the obtaining of nanohybrid compounds type amoxicillin/clavulanic acid-layered double hydroxides (Amox/CA-LDHs) followed by structural and morphological characterization of these nanostructures for future applications as drug controlled release systems. IR spectroscopy and Scanning Electron Microscopy pointed out LDHs ability to incorporate the medicines without modification of therapeutic activity.

Abstract: The aim of the present paper is to give an up-to date on computer aided design and manufacturing (CAD/CAM) additive techniques and synthetic polymers for bone reconstruction in the maxillofacial region. Additive manufacturing represents a promising field for future research in bone replacement/regeneration. However, standard guidelines for mimicking clinical environment with the different bone characteristics are strongly required. The rapid prototyping techniques, particularly, bioprinting allows the construct of 3D living functional tissues able to replace, in the near future, large defects caused by tumor excision, trauma, clefts or infections, limiting the autogenous bone graft requirement.

Abstract: Proper positioning of premature babies resulting from different maternal chronic conditions before pregnancy and hypertension induced during pregnancy can promote normal balanced development with maximizing the sleeping conditions and minimizing the gastric reflux. We conducted a retrospective study on data from Bega Clinics – Obstetrics and Gynecology and Neonatology for 2012-2013 about premature babies of mothers with pathologic pregnancies. Part of the newborns was positioned in a flexible polyurethane foam cocoon and clinical observations on sleeping states and the presence of gastric reflux were noted. In our study, 453 (10.5%) cases of women with different pathological conditions out of 4,312 cases were encountered. Most of them (48%) had a diagnosis of chronic hypertension, followed by chronic renal diseases (34%). Hypertension developed during pregnancy for both years, happened in 340 (7.88%) cases. Severe forms of hypertension were noted in 57.05% of them. Incidence of preterm birth babies was 11.22% (484 cases), of which 12 cases (8.67%) resulted from pregnancies with different forms of hypertension. Clinical observations stated that sleeping quietly and awake and quiet have increased the most when compared with babies positioned in the cocoon (44 babies) compared with babies (45) out of cocoons. Only 8 (18.2%) babies positioned in the cocoon experienced gastric reflux comparatively with 41 babies that were positioned in regular conditions.

Abstract: Acrylic resins based on polymetyl metacrylate are used in dental prosthetics as base for dentures. One of the major failure causes of dentures is the fatigue damage of the acrylic resins. These materials, in addition to mechanical behavior, also present a high risk of structural defects (voids, micro-cracks, residual monomer) that can significantly affect the fatigue behavior. In this paper, two commercial acrylic resins have been experimentally analyzed in terms of mechanical and fatigue behavior. Tensile constant amplitude fatigue tests with stress ratio R = 0 and frequency of 2 Hz have been carried out on samples of the two acrylic resins, prepared according to the manufacturer’s recommendations. The results revealed, besides the brittle fracture character, a similar fatigue behavior following a Weibull distribution. Also, through statistical processing of the results, the fatigue curve equations of the two analyzed materials were estimated for different levels of confidence.

Abstract: Our purpose was to study tibial plateau fractures considering the rise of their incidence, their potential immediate seriousness or late complications and their complexity. We realized a clinical-statistical study concerning the incidence of tibial plateau fractures taking in account critaeria like age, sex, mechanism of injury, fracture type and correlations between these. The study involves 126 patients, 98 (77.77%) being treated surgically and 28 (22.22%) conservatory between 2008–2016 in the I-st Clinic of Orthopaedics and Traumatology Timisoara. Approximately 2/3 of cases are of Schatzker type I, II and III. Type VI Schatzker occured in 5.78% of all, the mechanism of injury being split almost equal between road accidents and falls from height. Road accidents prevale as a causing circumstance of tibial plateau fractures. 2/3 of the tibial plateau fractures associate with other significant regional lesions. Bone lesions are not rarely underestimated by plain radiographs. Therefore evacuation of haemarthrosis (showing lipohaemarthrosis) and high performance imaging (CT, MRI) are often needed. In comparison to other fracture sites, imperfect reduction of tibial plateau fractures results more frequently in long term sequellae. Being frequently complex, comminuted fractures with associated regional lesions tibial plateau fractures raise the complexity of the medical act from establishing a complete diagnosis to the final therapeutic measures. For a correct and complete preoperatory diagnosis frequently high performance imaging is needed. Tibial plateau fractures significantly affect patients, the healthcare and social-economic system, the healing and rehabilitation.

Abstract: This article reports an environmental study concerning the liquid detergent contamination and its impact on some plantlets, e.g. Phaseolus vulgaris and Petroselinum crispum. In this context, this study focuses on specific modifications of the physical-chemical and biochemical characteristics of some plantlets induced by liquid detergents present in the soil, both bio-based and without environmental compatibility. The results of this study showed that a decrease (over 60%) in total chlorophyll per fresh weight could be solely due to the presence of non-biodegradable liquid detergents in soil, in various concentrations: 0.125%, 0.25% and 0.5% (wt/wt), calculated on water mass. On the other hand, the action of the detergents on the plantlets has revealed a decrease in the catalase activity in the case of both types of detergents.

Abstract: Compressive strength of the polymeric composites is an important data for design of composite structures and therefore a depth study of this mechanical property is imperative. The mechanical properties of the polymer composites vary in the very large ranges according to the characteristics of the constituents, to their proportions and many other factors. Compressive property and failure mechanism of polymer composite materials reinforced with glass fiber were investigated in this paper. The experimental data for the studied materials were included the compressive strength, strain, poisson’s ratio and modulus. Some of these experimental values could be affected by aberrant errors. This paper also presents an application that removes the experimental data affected by gross errors from the sample of numerical values. The elimination of experimental data affected by gross errors is based on Chauvenet criterion.

Abstract: The aim of this study was to evaluate and to compare the surface hardness of three types of resin-based materials used for direct restoration after heating at different temperatures. A giomer (Beautifil II, Shofu Dental), a compomer (Dyract eXtra, Dentsply Sirona) and a hybrid composite resin (Gaenial Posterior, GC Corporation) were selected for this study. Twenty disk-shaped specimens of each material were heated at room temperature (21°C), at 37°C, at 50°C and at 60°C. Vickers microhardness test was performed on top and bottom surfaces using digital microhardness tester (Micro-Vickers Hardness System CV- 400DMTM, CV Instruments Namicon). The top and bottom surfaces VHN was calculated as a mean value of five determinations. Also, the microhardness ratio was calculated by dividing the top mean VHN value by bottom mean VHN value. Increased mean hardness values were recorded after heating, irrespective of resin-based tested materials. The highest hardness values were recorded after heating all three materials at 60°C, followed by the hardness recorded at 50°C, 37°C and 21°C. For top surfaces, the lowest hardness value was recorded in Dyract eXtra group when samples were warmed at room temperature and the highest hardness value was obtained in Beautifil II group when samples where heated at 60°C. For the bottom surfaces, Dyract eXtra specimens heated at 21°C presented the lowest hardness values and Beautifil II samples heated at 60°C presented the highest hardness values. On top and on bottom surfaces Dyract eXtra showed the lowest hardness values, followed by G-aenial Posterior and Beautifil II, irrespective the heating temperature.

Abstract: We build a theoretical model based on a generalization of harmonic applications of Misner-type. It results a sine-Gordon type fractal differential equation whose elliptical solutions can describe, through a convenient choice of fractal dynamic constants, various modes of drug release. Thus, the entire class of empirical models (Higuchi, Korsmeyer-Peppas, Peppas-Sahlin) describing the drug release processes can be dispensed with.

Abstract: It is known, as well as a rule, that plastic materials can not instictively and naturally degrade when released into the environment. Due to the persistence of plastics to degradation and also to propagation in industry, the problem of plastic pollution has progressed considerable in order to become a threat to global ecology, on land and sea. The present study presents a global mapping of actions brought in to reduce the use of plastic, plastic bags and foamed plastic products, followed by selected case studies from each region of the world, with more attention offered to the European Union countries and the strategies elaborated by them to provide a cleaner and safer environment.

Abstract: The study aimed to highlight how unipodal stable equilibrium values are depending on the technical characteristics of plastic fitness equipment in relation to some anthropometric indices in order to optimize the physical potential. The best results recorded for the static balance test for both legs was on the Stability Disc, followed by Balance Board executions, and the weakest results were obtained on the Bosu Ball. The executions on the right leg were superior to executions on the left leg.

Abstract: Negative pressure wound therapy is one of the newest methods of treatment used in wound healing. An important role of the system has a foam dressing that connects the wound with the vacuum. In general the sponge used in vacuum assisted therapies is made of polyurethane foam. We present the case of a 51-year-old male patient with a history of deep vein thrombosis (known for about 3 years) diagnosed with necrotizing fasciitis (NF). In this patient, after each step of the surgical treatment (large debridement and skin grafting) negative pressure wound therapy using polyurethane foam was used.

Abstract: Flash-Free Orthodontic Adhesive System represents the latest technology in the field of orthodontics. In the present study the bonding technique is applied on CAD/CAM produced resin crowns. Ten resin blocks were shaped after an upper premolar crown design from the 3Shape Library, and they were divided ino two groups: on Group 1, control, Clarity Advanced braces (3M Unitek, Monrovia, CA, USA) were bonded using XT Adhesive Paste (3M Unitek, Monrovia, CA, USA), while on Groups 2 same aesthetic brackets were applied, using the APC Flash-Free Adhesive Coated Appliance System (3M Unitek, Monrovia, CA, USA). Bracket positioning time was recorded for each sample. Zwick Zoel Z005 testing machine was used to measure the shear bond strength (SBS) at which debonding takes place. Adhesive remnant index (ARI) was registered, as well as presence or absence of adhesive flash and accuracy of flash cleaning before curing. Group 1 showed a mean bonding time of 46.4 s, while Group 2 needed about 20.6 s for each bracket bonding. Mean SBS values for both groups are considered clinically acceptable (6.27 MPa for Group 1 and 7.77 MPa for Group 2). ARI scores were zero for all samples and after debonding, on group 1 can be observed the adhesive flash. In conclusion, APC Flash-Free Coated Appliance System showed reduced time for bracket positioning compared to the conventional technique. APC Flash-Free System showed acceptable SBS values, higher than the uncoated brackets. No composite was left on the resin crown after debonding, the adhesive flash resulted in the conventional technique remaining on the edges of the debonded brackets.

Abstract: Many of the chemical additives in the plastic products, besides the possible safety problems that may arise during the production process, have negative effecty, too, on the environment and human health. Plastic is a synthetic polymer. The polymers include starch, latex and cellulose, combined with different substances and chemicals, used in various formulas, the polymer is included in the naylon. At high temperatures such as microwave oven temperature, polymers can migrate from the packaging plastic in food. In most cases, establishing the diagnosis of allergic disease is a complex and difficult operation. This difficulty is primarily related to the polymorphism of the clinical manifestations accompanying allergic reactions, the existence during the evolution of these conditions, of long clinical asymptomatic latencies, as well as due to numerous subjective and objective symptoms that overlap with those caused by the allergen, complicating and altering the clinical picture. Allergies are an abnormal reaction of the body to allergens and develop in two stages. After the first contact with the allergen, the IgE antibodies are produced, and the second contact produces the allergic reaction. The produced antibodies will release the chemical mediators (histamine, prostaglandine, etc.) which cause an inflammatory response, vascular changes and irritation of the tissues, with the appearance of symptoms specific to allergy: redness, rash, itching, edema, etc.The so complex symptom of allergic diseases comprises several systems and organs at the same time, and the existence of over-additive phenomena makes it impossible to have characteristic clinical symptoms of allergic diseases that allow their identification only by clinical examination. However, this does not mean that the clinical exam and the analysis of the various objective and subjective symptoms presented by the patient is of no importance in establishing the diagnosis and recognizing the allergic character of the disease.The study includes a number of patients studied at the Galati Allergy Clinic. Specific immunotherapy known as desensitization or anti-allergic vaccination, is designed to fight the causes of allergies that occur when the immune system misinterprets harmless substances. Clinical examination results are complemented by allergen and specific antibody research; skin tests are the most common method for allergen detection.

Abstract: The development of antibiotic resistance in bacteria possesses a huge threat to public health by nullifying the effect of even the most efficient antibiotics. From years, LDHs type nanomaterials have been used as drug carriers for a wide variety of pharmaceutically active molecules due to their delivery properties, making these inorganic-organic nanohybrids very efficient antimicrobial agents. The major purpose of this work was to synthesize and characterize ceftriaxone intercalated layered nanostructures for further use to treat some infections, mostly of them child infections. The novel nanohybrid materials were prepared by ion exchange route and coprecipitation method. Structural and morphological characterization was performed by FTIR, EDX and SEM techniques. The results revealed a high incorporation of the drug in the interlayer space of promising nanostructures.

Abstract: The present paper is focused on analyzing if appropriate adhesion between the polymeric matrix and titania filler nanoparticles is obtained for the PMMA-TiO2 photo-curable dental material, suitable for application in RP - stereolithography (SLA) for complete denture manufacturing. It was found that different amounts, between 0.2% and 2.5 % (w/w%), of added titanium oxide nanoparticles slightly modify the structural behavior of the PMMA polymeric matrix. The material characterization was carried out using FT-IR and microscopy techniques.

Abstract: Using nanotechnology to produce composite materials it has been possible to obtain materials with similar or better mechanical properties than previous generation of microhybrids, and with exceptional aesthetics and chandelier due to the particularities of nanomaterials. At the same time, the improvement of adhesive techniques to enamel and dentin allowed the expansion of the area of direct composite restorations with a better prognostic over time.Eight carie-free molars were used and each of them was prepared with two class II cavities, which were filled using the C13 and C20 nanocomposites and the A1 and A2 experimental adhesive systems prepared at the Raluca Ripan Chemistry Research Institute. The teeth were divided into four groups of two teeth each, depending on the adhesive system and the composite material used. Scanning electron microscopy images (SEM) have described the adhesive interface and structure characteristics for the two nanocomposite materials and for the two studied adhesive systems.The studied nanocomposites have a variable number of porosities and air bubbles, with a clinical importance which is yet hard to establish.The experimental adhesives used produce a good interface and infiltration of the smear-layer but have not been visualized inside the dentinal canals.In vitro studies are necessary to evaluate the durability of adhesion in the case of self-etch adhesives in one or two steps.

Abstract: The species from the increased biofouling on the paint layers applied to the metallic strength structure of a railway bridge located in a Natura 2000 protected area have been identified by specific biologic and microbiological methods. As a result of the analysis of the biological samples taken on the field, it has been found that relatively large variety of filamentous molds are present (Aspergillus fumigatus, Asprgillus flavus, Aspergillus niger, Paecilomyces variotii, Chaetomium globosum, Trichoderma viride, Stachybotris atra, Trichoderma sp., Alternaria sp and Penicillium sp.). Samples also show, lichens (Xanthoria parietina and Hypogymnia physodes) and lower plants capable of photosynthesis such as algae (Chlorophyta Xanthophyceae, Chrysophyceae) and moss (Lunularia cruciata, Marchantiophyta).

Abstract: This paper presents a study undertaken following the collaboration between specialists in two multidisciplinary fields, namely engineering and medicine. It was aimed at solving a practical problem by developing of a handle for use in orthopedic surgery. Specific engineering tools, knowledge and processes and methods were used for accomplishing this task. Tailoring devices according to surgeons preferences for ensuring an ergonomic use is an important criterion alongside functional and sterilization requirements, cost and fabrication time, 3D printing representing a feasible manufacturing solution as this research proves. The article details the steps required to complete the final product: design and redesign, numerical analysis, prototypes manufacturing and testing. To perform the numerical analysis that highlights the device mechanical behavior, finite element method was used in assessing different handle designs.

Abstract: The aim of the present paper was to characterize the new pink PMMA doped with 0.4% TiO2 nanoparticles utilized for denture base manufacturing as alternative to the one-piece, single color material for removable denture. The PMMA base material was structurally characterized through XRD, SEM, EDX, and subsequently by FT-IR and Raman spectroscopy. An improvement in the thermal stability of the obtained material compared with the PMMA matrix without filler was evidenced. All performed structural analyzes are recommending the new pink PMMA with 0.4% nano-titania as an as an alternative to the one-piece, single color material for removable dentures processing.

Abstract: The paper presents the results of investigations on the transmission of electromagnetic radiation from the UV-Vis ranges of organic colored spectacle lenses. All investigated lenses had the same refractive index and one of them differed in the SPF (sun protection factor). The main criterion for the quality of colored eyeglass lenses is eye protection against harmful UV radiation, infrared radiation and excessive exposure to solar radiation. The lenses were measured using a Varian UV-Vis Cary model 300 spectrophotometer. These studies showed that the best protection against this radiation is the choice of coloring in a color other than blue, and that as the power of the colored lens increases, protection against harmful UV radiation decreases.

Abstract: The aim of this study was the development and formulating of a cosmetic product for bodycare and the assessment of compatibility tests performed on the product, transfered into a poliethylene (PE) cosmetic bottle. Sample of cosmetic cream were stored using 200 ml PE plastic bottles with PP (Polypropylene) cap. The developed cosmetic formulation was monitored under accelerated stability studies, performed over a period of 30 days while maintaining the product at 4, 20 and 40°C. Quality control initial, and after initiating the accelerated stability test was performed for the developed cosmetic formulation.

Abstract: One of the most common postoperative complications that may occur in patients treated for incisional hernias is pain. The occurrence of postoperative pain refractory to drug treatment may worsen the prognosis of these patients. We have carried out a retrospective observational study in which we have introduced 122 patients operated for incisional hernia at the Surgical Clinic No. 1 in the Tirgu Mures Emergency County Clinical Hospital. The patients included in the study were divided into two groups: group A consisting of 80 patients where the polypropylene mesh was used over the aponeurosis in the surgical treatment of the incisional hernias, and the group B consisting of 42 patients where no prosthetic materials were used in the surgical treatment of the incisional hernias. All patients were administrated 1 g of sodium metamizole monohydrate for the treatment of pain. The statistical analysis of the data revealed that, on the day of surgery, on the first, second and third postoperative day there were statistically significant differences in the need for analgesic medication between the two groups, the need for the analgesic medication being lower for group A. In contrast, on the 4th postoperative day there were no statistically significant differences in the need for analgesic medication between the two groups. In conclusion, our study showed that, when using the polypropylene mesh in the surgical treatment of incisional hernias, the need for analgesic medication is lower in the immediate postoperative period compared to cases where surgical meshes are not used in the surgical treatment of these patients.

Abstract: This article presents the design of a specific unmanned aerial vehicle UAV prototype own building. Our UAV is a flying wing type and is able to take off with a little boost. This system happily combines some major advantages taken from planes namely the ability to fly horizontal, at a constant altitude and of course, the great advantage of a long flight-time. The aerodynamic models presented in this paper are optimized to improve the operational performance of this aerial vehicle, especially in terms of stability and the possibility of a long gliding flight-time. Both aspects are very important for the increasing of the goals’ efficiency and for the getting work jobs. The presented simulations were obtained using ANSYS 13 installed on our university’ cluster system. In a next step the numerical results will be compared with those during experimental flights. This paper presents the main results obtained from numerical simulations and the obtained magnitudes of the main flight coefficients.

Abstract: This work has described the production of single-polymer composites by the film-stacking method. Two types of single-polymer composites with different mass fractions of the polyester reinforcement phase (10% and 20%) and the PETG matrix were investigated. The produced composites were subsequently recycled by injection moulding, pressing, and extrusion. Selected properties of the processed composites were determined: density, viscosity-average molecular weight, impact resistance, and tensile strength. The work done in this paper has demonstrated the benefits and drawbacks of each recycling method for these materials. The selected properties of single-polymer polyester composites and single-polymer polyester composites that were recycled by extrusion have also been compared.

Abstract: The purpose of this study was to determinate , using the Finite Element Analysis Method, the mechanical stress in a solid body , temporary molar restored with the self-curing GC material. The originality of our study consisted in using an accurate structural model and applying a concentrated force and a uniformly distributed pressure. Molar structure was meshed in a Solid Type 45 and the output data were obtained using the ANSYS software. The practical predictions can be made about the behavior of different restorations materials.

Abstract: Selection of sealing material is a problem in terms of long-term durability. In this regard, we have been investigating the in vitro structure and in vivo retention of composite resin sealant with BIS-GMA. Bi-dimensional and three-dimensional analysis by AFM highlights a homogeneous structure with no structural retaining areas of the material. Comparative in vivo and vitro evaluation of sealing resin revealed a correlation of the analyzed aspects in terms of the retention of the material used.

Abstract: The aim of this experimental study is to reveal the design and characteristics of unipolar shoulder prosthesis type Arrow (Groupe FH®, France) as well as to evaluate the outcome of the proximal humerus fracture treated with this implant. 8 patients with a mean age of 62.5 years were operated with immediate passive rehabilitation and active exercises initiated around day 45. All patients had good results with minimal pain, a mean Constant - Murley score of 74 and an acceptable shoulder amplitude. The clinical success was assured by the anatomic union of the tuberosities around the implant. The Arrow metaphyseal corundum blasted humeral titanium stem assures a perfect osseointegration with optimal stability and is an efficient alternative for shoulder hemiarthroplasty.

Abstract: This paper proposes to investigate in detail the behavior of polymeric membranes ultrafiltration process uses in the retention of humic acid from aqueous systems. Nowadays, the aqueous systems (contaminated water and/or wastewater) resulting from various domestic and industrial activities contain many contaminants, some of them increasingly dangerous to the environment. Laboratory testing of membranes in the ultrafiltration process as well as their experimentation with different chemical compounds is essential because it is important to know how they can be eliminated before they cause a negative impact. Testing of polymeric membranes consists in carrying out the process of ultrafiltration of aqueous systems containing humic acid over a set time, following the variation in time of the volume of permeate obtained as well as the influence of process parameters. Following the investigation of the ultrafiltration process of the water through the polymeric membrane, it was found that the formation of the humic acid layer on the surface of the membrane that favors fouling is delayed, after many hours of operation, due to both the internal fiber structure which offers advantages to this type of membranes as well as high efficiency of humic acid retention. Experimental results showed that the humic acid retention rate increased by up to 37% as a result of the double decrease of the conductivity value in the permeate samples from about 600 mS/cm to 373 mS/cm and the temperature being continuously increasing, from 22.5 at 25oC over 5 h influenced the entire ultrafiltration process. The full process approach as well as the expression and interpretation of the results will be detailed in this paper.

Abstract: The large diversity of clinical forms in Angle second class malocclusion explains the interest of researchers and clinicians in identifying changes in the dental arch in subdivisions II/1 and II/2. The purpose of the study is to identify the characteristics of the dental alveolar arch in order to determine the differences between class II/l and II/2 malocclusions. The study was conducted on dental gypsum models of 62 orthodontic untreated patients diagnosed with class II/1 Angle malocclusion, respectively class II/2. The results obtained by us reveals a statistically significant differentiation in the dental arcade, a narrowed maxillary arch at the molar level and elongated at premolar and molar level, in subdivision II/l. Our data are consistent with the results of literature. The knowledge of dental arch features serves to develop a correct and complete diagnosis and also to reach the therapeutic goals and to evaluate post-treatment response in short, medium and long term.

Abstract: The use of collagen scaffolds and stem cells for obtaining a tissue-engineering complex has been an important concept in promoting repair and regeneration of the bone tissue. Such units represent important steps in the development of an ideal scaffold-cell complex that would sustain new bone apposition. The aim of our study was to perform a histologic evaluation of the healing of critical-sized bone defects, using a biologic collagen scaffold with adipose-derived mesenchymal stem cells, in comparison to negative controls created in the adjacent bone. We used 16 Wistar rats and according to the study design 2 calvarial bone defects were created in each animal, one was filled with collagen seeded with adipose-derived stem cells and the other one was considered negative control. During the following month, at weekly intervals, the animals were euthanized and the specimens from bone defects were histologically evaluated. The results showed that these scaffolds were highly biocompatible as only moderate inflammation no rejection reactions were observed. Furthermore, the first signs of osseous healing appeared after two weeks accompanied by angiogenesis. Collagen scaffolds seeded with adipose-derived mesenchymal stem cells can be considered a promising treatment option in bone regeneration of large defects.

Abstract: The drug carriers represent a very important and modern pathway used to increase the therapeutic efficacy of the natural active substances. Nano-sized assemblies of noble metals and herbal extracts represent very simple, cheap, biologically and ecologically friendly synthesis. The main aims of this study were to obtain polyurethane nanovesicles containing silver nanoparticles and to evaluate their release rate. The vesicles’ sizes, homogeneity and surface charge were studied using a Cordouan Technol. Zetasizer, while the thermal behaviour was assessed by DSC. UV-Vis measurements were done to evaluate the release rate. Toxicological effects were studied by non-invasive techniques on human skin. The results suggest the obtaining of homogenous polyurethane nanovesicles between 80 and 95 nm, with positive surface charge, very good thermal stability and a prolonged release. The non-irritation potential recommends these vesicles as a safe carrier for different herbal extracts.

Abstract: Sewage sludge resulted from urban wastewater treatment plants is generally accepted as a valuable source of nutrient and soil conditioner for agricultural usage. Analysis of amount of heavy metals in sewage sludge is essential previous to utilization of the sludge to agriculture considering the inevitable risk of heavy metal toxicity to soil, vegetation and humans. The present paper aims to analyse the characteristics of the sewage sludge resulted in an urban area for 5 years. Sewage sludge generated from five wastewater treatment plants in the South and South Est part of Romania were analysed.

Abstract: In total edentulous treatment can be used a variety of means capable to reconstruct through artificial prosthetic devices the edentulous dental arches, in an individualized manner depending on the clinical situation, objectives and criteria for treatment. The present study was intended to evaluate the effectiveness of general treatment with vitamin B12 and the effectiveness of local treatment, achieved through complete dentures and to emphasize the much easier and cheaper way to do the same treatment over the same time period.

Abstract: The purpose of this experimental study is to present the design and biomechanical characteristics of cemented total knee prostheses type rotating-hinge RT-PLUS® (Smith&Nephew), as well as to evaluate their use in severe haemophilic knee arthropathy with major bone damage, ligamentous lesions, axial deviations and muscle retractions. We retrospectively evaluated 5 patients with severe haemophilic arthropathy with an average age of 48.5years. The functional results are good, with a significant improvement of range of motion (ROM) and pain relief resulting in a much better life quality. We did not have any stem loosening or any other complications except 2 wound healing problems which were treated successfully. The authors recommend this type of arthroplasty in severe haemophilic knee arthropathy or in any primary knee osteoarthritis with severe bone loss or any kind of ligamentous lesions.

Abstract: Importance and use of composite materials are no longer a subject that should be emphasized. They offer a successful replacement for classical materials in most areas of engineering, conferring similar elastic-mechanical properties to metal or non-metal alloys with several advantages such as reduced mass, chemical resistance etc. Considering this, knowledge of the elastic-mechanical characteristics is of utmost importance. The present article aims to create a finite element model that can predict the longitudinal elastic modulus of a double-layered composite material based on the elastic characteristics of its constituents. For this, the elastic characteristics of the constituents were determined, then used in the finite element analysis thus obtaining the Young’s modulus for the numerical composite material. Also, the longitudinal elastic modulus of the resultant composite was determined experimentally. The results of the finite element model were compared with experimental values.

Abstract: In this research are establish the technology of 3D printable parts by the principle of FDM 3D printed for threaded made by PLA, ABS, Nylon or PETG. In the paper are present first the dimensional generation and specific aspects that need to be considered to produce threaded with internal teeth of the metric, round or trapezoidal type. Generating the threaded appeared as a necessity for the reconditioning or made of the components of the processing machines made both in the process of elaboration of the bachelor’s and the laboratory works, with reduced energy resource consumption and low pollution as low as possible. After the construction, it is identify the dimension that have implications for both mechanical and kinematic resistance to make a product with good cinematic and functional characteristics. After that are made an analysis of the layers generated, both from the computer simulation and from the point of view of the analysis of layers physically generated for a threaded with internal teeth. At the end are presented which are necessary for operations to obtain a product with good features starting from two types of thread generated 8x2 and 10x2 moments.

Abstract: Turmeric, with its active component curcumin has been regarded lately as an important potential therapeutic agent due to its properties and many uses. Further research needs to be done both on animals and humans in order for it to be used at a large scale. As curcumin gets absorbed better through topical and not oral administration, curcumin-based pharmaceuticals with skin passage must be devised. In order for this to be done, the need for a standardized, verified and simple extraction method and one for ointment preparation with stability in time rises. We propose in this study a method for curcumin extraction, one that ensures an adequate stability in time and a method for pharmaceutical control.