Volume 54, Issue 2

Abstract: The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.

Abstract: The paper presents the results of the experiments on obtaining a composite material to be used in manufacturing brake shoes for the rolling stock. The aim was to replace the classical material used at present for the manufacturing of brake shoes: cast iron with a specially designed composite material. Six recipes have been tested and compared to a standard sample made of phosphorous cast iron. The wear trials carried out in laboratory conditions on the experimental test rods have led to results that entitle further experiments that implies the manufacturing of brake shoes made of the composite material in question.

Abstract: In this work, we focused on the potential of biogenous mineral from Cuttlefish bone for inducing biomimetic mineralization with further biomedical applications. We demonstrate the formation of strong and flexible hydrogels via physical immobilization of cuttlefish bone powder in the presence of bovine gelatin and alginate. The properties of hydrogels loaded with biogenous mineral, with a commercial bone substitute, with commercial nano-hydroxyapatite and in situ generated hydroxyapatite. In vitro cell adhesion tests demonstrated that the new developed hydrogels showed a promising cell adhesion.

Abstract: The first part of the paper presents the influence of the processing temperature by injection of HDPE, of PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when other factors that can influence the injection remain unchanged. The second part of the paper presents the influence of subsequent pressure by injection of HDPE, PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when the other factors 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 bar, 900 bar, 1000 bar, 1100 bar, 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, 800, and 900 bar. The G-Series Basic Hardness Modulus at a Depth method was used to obtain the indentation hardness and the indentation modulus. It was observed that by increasing the processing temperature and subsequent pressure, in the case of HDPE, leads to an increase in indentation hardness and in indentation modulus. It was observed that increasing the processing temperature by injection in the case of PMMA, from 220 to 250°C, leads to a slight increase in indentation hardness and in indentation modulus, whereas increasing the subsequent pressure of PMMA, from 450 bar to 850 bar, leads to a slight decrease in indentation hardness and in the indentation modulus. Increasing the processing temperature by injection in the case of PC+ABS, from 230 to 250°C, leads to a slight increase in indentation hardness and in indentation modulus. By further increasing the processing temperature by injection, from 250 to 270°C, leads to a decrease in indentation hardness and in the indentation modulus. Alternatively, increasing the subsequent pressure from 500 bar to 900 bar leads to not only a decrease in indentation hardness but also to a decrease in the indentation modulus.

Abstract: A constant situation present in the anatomy laboratories is represented by the cadavers preservation resulted from dissection. The main requirement for this process is the use of formaldehyde which is a toxic substance probably included in the class of carcinogenic substances. Large specimens resulted from dissection process, such as limbs or trunks, can be preserved only in large containers filled with formaldehyde and for limited periods of time. To remove these issues we used the anatomy laboratory in order to be able to preserve the first sustainable plastinated anatomical specimens. In our study have been used 8 adult human bodies (partial and complete), 6 females and 2 males, aged between 62 and 73. We have removed and dissected brains, upper limbs, kidneys and livers. They have undergone preservation process of plastination.

Abstract: The work presents the results of a computer simulation of one of the most widespread strength tests, i.e. a static tensile test, performed with the use of two design tools - ANSYS and SolidWorks software. Strength tests were performed with the ZWICK Z100 tensile machine. The shaped sections used in the analysis were made of AW-6060 aluminium alloy. The computer simulation results were referenced to the actual tensile test results and it was found they are comparable. It can be concluded on such basis that a computer simulation is an alternative to time-consuming and costly laboratory tests.

Abstract: Synthetic meshes are steadily developed and optimized to provide the best biocompatibility, resistance and elasticity with minimal side effects when used in vivo. This article presents mesh parameters, which influence the biological outcomes in surgical cases. Material, structure, resistance to the applied force, elasticity and biocompatibility are listed below in order to clarify the advantages and shortcomings of different mesh types. Future developments in synthetic mesh industry are presented as well in order to improve mesh acceptability in vivo and optimize healing process. There is no ideal mesh, but only prostheses with fewer side effects when correctly used, in accordance with patient needs.

Abstract: Luffa cylindrica fibers were purified through alkaline treatment and loaded with phosphate as mineral precursor. Their capacity of acting as bioactivator for an inert polymer was evaluated. In this respect, the PO43- - Luffa fibers were loaded in a polymeric matrix known not to promote biomineralization through immersion in mineralization media. The synthesized materials were subjected to alternative Ca/P baths and the formation of mineral was investigated through SEM. Also, the mechanical properties and the water affinity of the un-mineralized and mineralized materials were investigated.

Abstract: The aim of study was to analyse the activity of four biocides. Assessment was made using the methodology described by the Clinical and Laboratory Standards Institute (CLSI); Antifungal Susceptibility Testing of Yeasts, M27-A3 Approved Standard, in: Candida sake, C. albicans, C. lusitaniae and Rhodotorulla rubra. The outcome, related to the culture2 s cut-off value of optical density (O.D.) was analysed statistically (p = 0.05 or lower) proving that Candida albicans was capable of generating strong biofilms, in the resistance setting (p = 0.001).

Abstract: The aim of this study was to evaluate the interim veneer restoration, achieved from two types of dimethacrylate based composite resins (Telio CS C&B and Luxatemp Star), by direct technique. Both composite resins performed well according to evaluation criteria: anatomic configuration, marginal adaptation, discoloration, surface texture, postoperative pain and periodontal aspect. Loosening of interim restorations appeared in 25% of cases. Besides advantages, there are some disadvantages associated with direct way of achieving temporary veneers.

Abstract: In the recent years, engineered nanoparticles (NPs) such as PLGA or poly-lactic-co-glycolic acid, have raised a substantial interest due to their possible medical applications in vaccination, diagnostic imaging procedures, cancer therapy or sustained delivery of drugs. The main aim of the present work is to evaluate key oxidative stress parameters in several organs following NPs administration in an animal model. Our data shows that acute oral administration of PLGA NPs induces a change in the antioxidant status in both rat liver and spleen, but may not induce oxidative stress damage to cell structures such as lipid or protein oxidation.

Abstract: One hundred micro-implants from two different manufacturers were used in the study. From each manufacturer (Link from MISTM and Yesanchor from OrlusTM) the implants were divided in 5 groups: G0 (n=10) new, unused, G1 (n=10) mini-implants inserted in pig bone and removed, ultrasonically cleaned, followed by autoclave sterilization, G2 (n=10) same insertion protocol of group 2 followed by chemical cleaning with phosphoric gel and autoclave strerilization, G3 (n=10) same insertion protocol of group 1 followed by sandblasting and autoclave sterilization, G4 (n=10) same insertion protocol of group 2 followed by cleaning with distilled water and autoclave sterilization. Maximum insertion torque was recorded and subjected to statistical testing. Our results showed significant differences of the maximum insertion torques between groups of Link mini-implant (p=0.006), and no statistical differences of the maximum insertion torques of the Yesanchor implants (p=0.33). Significant differences (p[0.001) were also recorded between the groups of the two types of minii-mplants when compared. Our findings showed that brand-specific differences in maximum insertion torque exist between the two types of mini-implants.

Abstract: The activity of using membrane technology has developed fast in the treatment of wastewater, drinking water and process water production. The main challenges in membrane filtration are fouling reduction, permeability increase and high efficiency in retention. The best example of membrane enhancement is increasing hydrophilicity. Nanoparticles have been proven that their presence in the membrane matrix increases the water affinity significantly. Although the zinc oxide nanoparticles have a positive effect over the membrane performance, the influence of zinc oxide (ZnO) nanoparticle size has not been studied enough. Two sizes of nanoparticle of ZnO and three concentrations were used for the preparation of composite polysulfone ultrafiltration membranes. The effects of the ZnO nanoparticles in the membrane matrix on the permeation properties, flux stability and retention were tested. SEM, EDX, porosity and contact angle measurement were conducted in this article, also. The experimental results indicated that ZnO-PSf composite membranes exhibits significant differences in the membrane properties due to nanoparticle addition and regardless of their size it leads to an increase in hydrophilicity, flux, permeability, retention and porosity. Decreasing the nanoparticle size leads to an increase in membrane performance.

Abstract: There is limited data of short-term outcomes comparing press-fit bipolar and cemented total hip replacements in patients with femoral neck fractures. We therefore aimed to compare the perioperative incidents and immediate outcomes between press-fit stem bipolar head hemiarthroplasty and cemented total hip replacement in elderly patients with displaced femoral neck fractures. We reviewed prospectively collected data from 115 consecutive patients over 12 months. There were 21 cemented total hip replacements and 33 bipolar head press-fit stem hemiarthroplasties, with a male to female ratio of 1:1.84 and an average follow-up of 9.9 months (range 3-15). There were no differences between the two groups with respect to age (mean 77.4 years old), cortical index (0.77/ 0.82, p=0.087), hospitalization (17.7/ 16.7 days, p=0.59), bleeding, blood transfusions (14.3/ 18.2%, p=1.00) and Barthel index preoperatively, at discharge and 3 months (5.67/ 5.48, p=0.62; 10.57/ 10.47, p=0.89; 13.81/ 13.28, p=0.47). For all 54 patients the hemoglobin dropped from 13 to 11.2 g/dL after surgery without difference between implants. The mean duration of surgery was 21minutes (p[0.01) shorter for the press-fit hemiarthroplasty group compared to cemented total hip replacements. Our findings show comparable blood loss and functional outcomes with press-fit bipolar hemiarthroplasty and cemented total hip replacements for treating displaced femoral neck fractures in the elderly. Both were safe and allowed early recovery, with the only significant difference being the longer duration of surgery for the total arthroplasty.

Abstract: The fixed mixed prosthetic restorations (FMPRs) are often manufactured in dentistry. Fixed prosthetic restorations mixed (RPFM) are often used in dentistry. The aim of the study was the presentation of the deficiency and the differences arising between FMPRs with metallic framework plated with two types of dental resins, currently used frequently in Romania, Superpont C + B (Spofadental, Czech Republic) and Royaldent (Palatine Foggyart, Hungary). We have achieved at 102 patients, 132 FMPRs coated with Superpont C+B and Royaldent resins. Patients were divided into two equal groups according to dental polymer used for coating. Long-term study was conducted by biannual monitoring, over three years. The results of the study showed that both resins degrades over time, from the point of view of their physical appearance and their aesthetics, and induced the apparition of gingival inflammation, but restorations coated with Royaldent resin showed less irritation of the gingival tissues.

Abstract: The paper presents the experiments performed in the laboratory and the results obtained on friction and wear behaviour of the composite materials for the manufacture of brake shoes used for driving and towed rolling stock. The tribological research of these samples made of composite material with organic components aimed to determine the influence of certain material factors and operating regime parameters on the tribological properties of the tested samples. The brake shoes made of composite materials oneusesto replace the conventional cast iron brake shoes, to reduce the noise. The future research will focus on finding composite materials with superior properties compared to the currently used ones, and lower costs.

Abstract: This paper analyses the influence of processing temperatures of acrylonitrile butadiene styrene (ABS), polyamide 6.6 (PA 6.6) and polyoxymethylene (POM) on some electrical properties when injecting items used in the automotive industry. The ABS specimens were made at the following injection temperatures: 220, 230, 240 and 250°C. The PA 6.6 specimens were made at the following injection temperatures: 280, 290, 300, 310 and 320°C. The POM specimens were made at the following injection temperatures: 180, 190, 200, and 210°C. The determination of electrical properties were carried out using the methods for determining the relative permittivity and the dielectric dissipation factor using zero method with Schering bridge. It was found in the three polymers analysed that the temperature rise processing by injection leads to insignificant changes in relative permittivity (er) and dielectric dissipation factor (tgd).

Abstract: Testing of fire safety is based on the premise that a band should not be a fire, it would be hard to ignite and if was ignited by an external source of fire should not flame retardant. While fire resistance specifications vary from country to country, formulated to meet any fire performance specifications in the world. Tests on conveyors to assess their compliance with fire safety standards are: Drum friction test: The danger associated with a stalled belt and a driven rotating drum or pulley resulting in frictional heat build up. Laboratory flame test: The possibility of igniting the considerable mass of a conveyor belt with a relatively small ignition source. Gallery fire test: The possibility of a belt, ignited from a larger ignition source, spreading the fire to other areas (often referred to as fire propagation). Electrical resistance test: The possible build-up and subsequent discharge of static electrical charge on moving conveyors.

Abstract: In this research, the impact behavior of hybrid composite materials subjected to low-velocity impact using the drop-weight installation was investigated. For this study were manufactured eight hybrid materials. All the materials were tested to 90J impact energy. The effect of fabric types used in outer layers on impact performance was studied. The impact characteristics of hybrid materials with G1 glass fabric sheets were compared with those of hybrid materials with G2 glass fabric sheets. The damage surfaces of hybrid laminates were examined by visual investigation. The results obtained showed that the using of G2 glass fabric in structure of hybrid materials improved considerable the impact characteristics.

Abstract: Our study aimed to identify inorganic elements and bacterial load on the inner surface of the CPAP masks and tubing using scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) and microbiological surface analysis. By SEM were identified structures similar to Staphylococcus and Candida types. When completed by EDX were identified Cl, K, Ca, O, Ti, Na, Mg, Al, Si, S, Cl. Microbiological analysis identified Staphylococcus epidermidis (5000 CFU/mL), Staphylococcus hominis (8600 CFU/mL), and Staphylococcus haemolyticus (6500 CFU/mL). The presence of microbiological and inorganic structures raises concerns on the risk of their inhalation into the airways.

Abstract: Introducing polymer ligating clips (PLC) or Hem-o-lok clips was a useful alternative to titanium clips in order to perform a safe, efficient and rapid ligation of the vascular structures during laparoscopic and/or conventional surgical procedures. In urologic surgery they are useful during ablative laparoscopic surgery for renal tumor, urothelial tumors, non-functional kidney, bladder tumors and prostate tumors. Polymers’ properties depend on the structure of molecules and vary from flexible substances to expandable rigid materials. They have a high resistance to shock, considerable abrasion resistance and precise durability. Polymers can easily take the desired shape, due to different processing modes. They also have the property of resistance to sustainable action of external forces. The aim of this paper is to evaluate the efficacy and safety of PLC used during renal pedicle ligation in retroperitoneal laparoscopic nephrectomy for renal tumors, high urothelial tumors and nonfunctional kidney.

Abstract: The purpose of this experimental study is to present the design and biomechanical characteristics of bipolar polyethylene radial head prostheses type KPS (CHM â Poland), as well as to evaluate their use in comminuted fractures type Mason III associated with ligament injuries. We retrospectively evaluated 7 patients with 7 complex radial head fractures with an average age of 38.5 years. The prostheses were implanted through a lateral Kocher approach and patients immediately began the rehabilitation of the elbow. The functional results according to the MEPS score (Mayo Elbow Performance Score) were excellent in 3 cases and good in 4 cases, without stem loosening or residual instability of the elbow. Due to the overwhelming advantages of this bipolar prosthesis (better joint tracking and easier implantation technique) and its very good functional results, the authors recommend this type of arthroplasty in posttraumatic elbow instability.

Abstract: Polyartetrtys nodosa (PAN) was diagnosed histologically in a dog 14 months old, that presented in the necropsy a hemorrhagic diathesis. The specific lesions were present in the muscular arteries of middle and small caliber and in the arterioles from heart. The modifications are segmentail, chronic, evolving from fibrinoid necrosis to the polyphasic, transmural, neutrophilic, leucocytodastic, macrophagic, lympho-plasmodtic and finally fibrotic vasculitis. The elastolisis predisposes to micro-aneurisms and micro-hemorrhages. Unlikethe perivascularitis, the inflammatory processis extended to the surrounding tissues.

Abstract: Sleep apnea episodes represent a problem both for the patients and for the patient’s bed partners. The objective of this study was to record the comparative effects of two types of polymeric appliances in the therapy of some mild apnea symptoms (bruxism and snoring). The effect of therapy with the used appliances was pursued on 42 patients, divided in two groups. In the first group of 21 patients, we used a custom made appliance achieved by Erkoflex disks, and in the second group of 21 patients, the preformed SomnoFit®-Oscimed polymeric appliance. The survey lasted for a 12 month period, 1 month before the insertion in mouth of the appliances and 11 months therapy with polymeric appliances. The authors’ questionnaire was completed daily by the patients and their bed partners, which noted the night comfort with inserted appliances in the mouth, the existence/absence of morning pain in the area of the masseter muscle, existence/absence of the morning fatigue, respectively the maintaining, diminishing and the absence of snoring and of nocturnal bruxism. The results of the study were favorable and proved that the nocturnal therapy of bruxism and of snoring, by using these two polymeric appliances were efficient. SomnoFit® appliance performed better in reducing bruxism and snoring, but custom made Erkoflex appliances presented a greater resistance in time.

Abstract: The aim of this study was the evaluation of the long term results in the clinical applicability of two root canal sealers, Sealapex Xpress - Kerr Endodontics (non-eugenol, calcium hydroxide polymeric root canal sealant) and AH Plus Jet - Dentsply Maillefer (epoxy resin-based sealant). 225 teeth of 159 patients included in this study, were endodontic treated and filled with the previously mentioned root canal sealers, in accordance with a standard clinical protocol. The long term results regarding the evaluation of the used two root sealers were realized clinically and radiologically, after annually monitoring conducted during three years. Long-term results of the study showed that, although their different chemical composition, the two root filling material showed good results in the treatment of various types of endodontic disease.

Abstract: This paper aims to assess the postoperative evolution of edentulous patients treated by guided bone regeneration technique using a xenograft bone substitute (Cerabone) and collagen membrane. A group of 40 patients, programmed for guided bone regeneration, randomly divided between laser-assisted technique and scalpel technique, were investigated to compare the postoperative evolution, healing time and prevalence of new bone formation, graft stability and inflammatory reactions. The guided bone regeneration technique associated with laser or scalpel technique offers reliable and predictable treatment results in the implant-prosthetic treatments. The accelerated healing time recommends the laser technique in the surgical procedures used for the alveolar augmentation.

Abstract: The objective of this study was to analyse the role of package obtained from a natural biopolymer of Quercurs robur L incorporating natural antioxidant compounds found in roasted seeds of grapes to lipid oxidation of butter during storage. Also were determined the properties of film: solubility in water, determination of antioxidant activity and water sorption activity. Were formed two sets of butter samples packed in paper respectively in a biopolymer mixed with antioxidant. Samples were stored at a temperature of +6°C for a period of fourty days. Frequently was determined the peroxide index. The values of peroxide index show the role of package obtained from starch and polyphenolics extract of roasted seeds of Vitis vinifera grapes on lipid found in butter.

Abstract: High printing quality of banknotes and the variety of security features implemented in banknotes make a big difference between the genuine notes and high-quality forgeries. The counterfeiter cannot reproduce or imitate the printing quality and all security features embedded in every banknote, such as Optically Variable Ink, Optically Variable Diffractive Images, or intaglio printing. The present research focused on the examination of optically variable devices embedded on 50Îbanknotes. The altered banknotes were examined using different techniques.

Abstract: The paper describes an innovative method of production of non-ferrous drop forgings, a manufacturing method based on closed die forging without flash. From economic point of view, this method is very interesting for production, due to small quantity of lost material. The research was verified using DEFORM 3D software. In this way can be better understood the principles of forging process and can be analyzed the plastic flow of the material into the die cavity. This experiment was successfully performed at laboratory conditions and the results will be applied in practice.

Abstract: In order to evaluate the durability of paint layers exposed to simultaneous action of climatic and electrical stresses, the influence of 50 Hz electrical field and of aging by thermal cycling on the resistance to the action of molds of some painting materials was evaluated by specific microbiological determinations. Comparative measurements were carried out on initial paint samples and samples aged by applying of 1000 successive thermal cycles (between –38oC and 85oC, with the duration of a cycle of 90 min), exposed to Czapek-Dox culture media (with and without sucrose), inoculated with a salt solution containing approximately 106 mold spores (of 10 different species), and incubated at 30±2oC and RH 90±5%. It was found that for the samples exposed to a controlled field of 5V/cm and 50Hz the resistance to the action of molds is almost two times less than in the absence of the disruptive electric field. Also, it was noticed that the field of 5V/cm and 50Hz stimulates the growth of Aspergillus niger, but completely inhibit those of Trichoderma viride and Aspergillus flavus.

Abstract: On a total of 150 renal corrosion casts were examined the posterior branch and the artery of renal posterior segment. For the origin of the posterior branch, there have been highlighted three morphological types, namely: Type I, bifurcation in anterior and posterior branches (92.67% of cases); Type II, trifurcation in anterior, posterior and superior or inferior branches (6.00% of cases); Type III, quadrifurcation in anterior, posterior, superior and inferior branches (1.33% of cases). Depending on the relations between this path and those with the posterior aspect of the renal pelvis, we highlighted four morphological types: Type I (62.67% of cases) with large extension of the posterior segmental artery, convex downward path and multiple subsegmentary branches; Type II (34.00% of cases) with large extension of the posterior segmental artery, that bifurcates or trifurcates in segmental branches and convex downward path; Type III (2.00% of cases) with small extension of the posterior segmental artery, with downward path in relation to the upper portion of the posterior surface of the renal pelvis upper portion; Type IV (1.33% of the cases) with small extension of the posterior segmental artery, with upward trajectory in relation to the lower portion of the renal pelvis. Knowledge of these aspects is important both to investigate morphological imaging and for performing partial resection of the renal parenchyma.

Abstract: The goal of this paper was to study the modification of porous clay heterostructures (PCHs) with various silane coupling agents. Two commercial coupling agents (3-aminopropyl-triethoxysilane (APTES) and 3-glycidoxypropyl-trimethoxysilane (GPTMS)) with different functional groups (amine and epoxy groups) were used as modifying agents for the PCHs functionalization. The functionalization of PCH with APTES and GPTMS was evaluated by Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TGA), X-Ray Diffractions (XRD) and BET Analysis. FTIR spectra of modified PCHs confirmed the presence of characteristic peaks of silane coupling agents. TGA results highlighted an increase of weight loss for the modified PCHs that was assigned to the degradation of silane coupling agents (APTES and GPTMS) attached to the PCHs. The XRD results showed that the structure of modified PCHs was influenced by the type of the silane coupling agent. The functionalization of PCHs with silane coupling agents was also confirmed by BET analysis. Textural parameters (specific surface area (SBET), total pore volume (Vt )) suggested that the modified PCHs exhibit lower values of SBET and a significant decrease of total pore volume than unmodified PCHs.

Abstract: According to titanium’s much higher hardness and strength compared with the bone, if correctly applied, mini-screws will suffer no damage. Reusing orthodontic mini-screws would reduce treatment cost and lead to more use of mini-screws and improvement of orthodontic treatments. In this study, scanning electron microscopy (SEM) was used to assess structural variations of retrieved orthodontic implants and to evaluate the mechanical properties that may adversely affect stability of orthodontic implants. For analisys 10 self-drilling mini-implants retrieved after treatment, made from commercially pure (CP) alpha-titanium from two brands Leone™, Italy and ForestaDent™, Germany were analised using SEM according to the degree of morphological deformation of the head, transmucosal neck, threaded body, and tip of the implant at up to 10,000 x light magnification. The mini-implants did not present any defects such as bubbles, imperfections or fissures in their internal microstructure. No significant marks resulting from the manufacturing process were observed. Surface irregularities in the threaded body and tip (fig. 5-7) were observed and significant tip deformation was evident in the majority (80%) of retrieved mini-implants.

Abstract: Antibacterial gels offer an efficient hygiene in the absence of soap and water. The most part of these products are based on mixtures of different antibacterial and fungicide substances dissolved in an alcohol. Unfortunately, all cosmetic products containing alcohols wash the sebum and dry the skin. In the present study, alcohol-free antibacterial hydrogels were obtained through the synthesis of polyurethane (PU) microstructures with an increased amount of surfactant; 5-mercapto-1,2,4-triazole derivatives were used as active compounds inside the PU microstructures as antibacterial agents. There were studied: the pH of samples, the size and stability of PU microstructures, the skin irritation, sebum level and the hydration of stratum corneum using the mouse model and their efficiency against Escherichia coli. The results indicate that were obtained hydrogels with a slightly acid pH, PU microstructures with sizes between 185 and 265 nm and with a medium stability. It was found that these new antibacterial hydrogels do not produce an important modification of skin parameters (erythema, melanin, sebum and hydration of stratum corneum) and are efficient against E. coli.

Abstract: In this paper, were study the pervaporation of mono-nitrophenols in a laboratory installation of the Membrane, Materials, and Membrane Processes Group of the Polytechnic University of Bucharest, from aqueous synthetic solutions, to composite membranes with polysulfone matrix (PSf) and nanometric inclusions: Polyaniline (PANI), carbon nanotubes (CNT), magnetic nanoparticles (MNP) and sulfonated polyetheretherketone (PEEK-S). Tests carried out over 144 h at a pressure of 100 mm Hg or 5 L / min air flow at 25oC and pH 7 of the feed solution show that vacuum pervaporation is better than vacuum. The more advanced composite membranes are those with sulfonated polyether-ether cellulose (PSf-PEEK-S) and polyaniline (PSf-PANI) ionizers. The results of airborne pervaporation show that composite membranes (PSf-PEEK-S and PSf-PANI) present a marked difference in flux for the mono-mono-nitrophenol isomers, which could also be found in a technically exploitable selectivity. Thus, in the case of the PSf-PEEK-S composite membrane, the mono-nitro-phenol streams decrease in the order: m-C6H5NO3] o-C6H5NO3] p-C6H5NO3, while for the PSf-PANI composite membrane the order is o-C6H5NO3] m-C6H5NO3] p-C6H5NO3. At the same time, it is noted that the PSf-PEEK-S composite membrane performance is superior during operation, but shows the opposite of the more pronounced drop.

Abstract: Collagen is an important natural biopolymer, found in mammal’s body. It is the main structural protein in the extracellular space in the various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals. Its importance increased in last decades. Collagen has many applications in medicine and cosmetics. The work presented in this paper shows one method to obtain collagen films from collagen solutions. These collagen solutions were characterized by rheological measurements. The preparation of the collagen films was performed in the presence of calcium and silicium salts, using glycerin as plasticizer. The collagen was first solubilized and reconstituted, in order to maintain its initial properties.

Abstract: Due their various applications the fabric reinforced polymer composites are subject of a large number of researches especially for aero- and automotive industry. Regarding the last domain there are huge interests in designing and forming composites with controllable strengthens for car bodies able to protect both the driver and passengers inside and pedestrians in case of unfortunate events. In this regard, based on previous studies developed at the Research and Development Centre for Thermoset Matrix Composites, our proposal is to design the bending behaviour of a fabric reinforced materials by means of changing the bending strength of the polymer matrix using a solvent. 1-Methyl, 2- pyrrolidinone is a well-known polymer solvent that had been used in previous studies as vector to transfer various organic agents into epoxy resins. During those studies it had been noticed that the presence of above mentioned solvent is changing the bending behaviour of polymer samples and induces some properties that are belonging to memory-shape materials. The present study is related to mechanical analysis of a multi-layered material (fabric layers) immersed into an epoxy resin having a graded bending strength.

Abstract: n the current paper, we aimed to analyze the way in which packing (different polyethylene types) influence the quality of pasteurized melange during storage, packing being realized in units of 1 kg (Tetra Pak) (batch Lexp-1) and units of 5 kg (Bag in box) (batch Lexp-2). Products were stored during a period of 28 days at a temperature of +4°C, qualitative determinations being realized in first day (day 0), at 7 days, at 14 days, 21 days and in day 28 of storage. Were effectuated a sensorial examination and chemical analysis were was established the content in dry matter (%), water (%), proteins (%), content in essential amino acids (isoleucine, methionine, tryptophan, phenylalanine) and non-essential amino acids (alanine, histidine, glycine, serine) (mg/100g) as well as the content in lipids (%) establishing their profile by identification of some saturated fatty acids (16:0 mg/100g and 18:0 mg/100g) and unsaturated fatty acids (16:1 mg/100g and 18:1 mg/100g). After sensorial examinations, the first modifications were observed at the checking effectuated in day 21 for batch Lexp-2, the obtained score being of 18 points, and at checking effectuated in day 28 was given a score of 18 points for melange belonging to batch Lexp-1 and only 14 points for melange from batch Lexp-2. Differences were recorded also in case of chemical composition of products, so for protein content at batch Lexp-1 in first checking day was obtained a mean of 12.730±0.24% and at batch Lexp-2 12.614±0.22%. Differences between those two batches were insignificant (p < 0.05). In case of fat content, at the end of storage period was obtained a mean of 11.256±0.06% for batch Lexp-1 and 11.244±0.11% for batch Lexp-2, differences being insignificant (p < 0.05). Regarding the profile of amino acids and fatty acids, the mean values obtained during whole storage period oscillated from one stage to another, but the differences between those two batches were insignificant (p < 0.05). Pasteurized egg melange suffers certain sensorial modifications during storage, especially on consistency and colouring, modifications which are accentuated mainly by storage conditions. Type of polyethylene utilized for this product hadn’t influenced the nutritive qualities of product.

Abstract: The aim of this in vitro study was to to evaluate the impact of finishing procedures on the enamel adjacent to composite restorations and to assess if the resistance of the enamel-resin junction to leakage is affected by the use of these instruments. The surfaces of enamel at the joint with composite were observed by scanning electron microscopy, then the microleakages at the enamel margin was assessed using an optical microscope. Finishing with extra-/ ultra-fine carbide burs and extra-fine diamond burs produced a superficial abrasion to the adjacent enamel and did not seem to have a significant influence on the sealing ability of composite resin.

Abstract: The aim of the study was to investigate the dynamics of the main chemical compounds in the powdered eggs stored under constant environmental conditions (temperature=10±0.5oC; relative humidity=65±1%) and packaged in bags made of different plastic fabric (Lc group = high density polyethylene – HDPE; Lexp group = low density polyethylene – LDPE). The assessments were run to measure the inner water and dry matter contents, as well as the ash, proteins, lipids and nitrogen free extract levels. The analysis of data gathered throughout 90 days of storage suggested that the product packaged in low density polyethylene bags – LDPE (Lexp group) absorbed +0.82% humidity from the environment, compared to Lc group (highly significant differences), lost 0.41% from its initial proteins level and 0.59% of the nitrogen free extract, while lipids and ash values were not affected by the experimental factor (different package). Consequently, it might be concluded that the type and quality of the utilised package could significantly influence the proximate chemical composition, due to the transfers from the outer storage environment toward the inner volume of the package, whose intensity is given by the direct influence of the barrier features of the fabric the packages are made of.

Abstract: Growing demands from industry for the use of eco-friendly lubricants led research towards finding environmentally friendly products with superior lubricating characteristics. Vegetable oils and synthetic ester oils are competitive base oils used to obtain lubricants with good physico-chemical, rheological and tribotechnical properties, biodegradable lubricants without negative environmental impacts. In this study we aimed the synthesis and characterization of bioesters with lubricant properties, using as acid component the soybean oil fatty acids in conjunction with the following hydroxyl compounds n-buthanol (P1) and 1,2-propilenglycole (P2), respectively. These complex esters were synthesized in a microwave reactor in a single stage in the presence of the catalyst at the reflux temperature. Characterization was carried out in the respective of structural point of view and as a lubricant.

Abstract: This paper aims to synthesize the main categories of biomaterials (bone substitutes, collagen membranes) used in the reconstruction of oral bone defects and alveolar augmentation by guided bone regeneration technique. The review of literature data shows that guided bone regeneration technique offers reliable and predictable results in the implant-prosthetic treatments.

Abstract: Resin-based pit and fissure sealant materials are heterogeneous materials with two principal components: the resin matrix and the filler particles. The shear bond strength test holds great importance for providing insight into the adhesion of these materials and, also, it is a screening mechanism for predicting clinical performance. The purposes of the present study are to investigate the structure of surface and the shear bond strength for two commercial pit and fissure sealants, Fissurit (VOCO) and Pit &Fissure (DMP) sealer. Seal Fissurit had the highest shear strength, and the difference was statistically significant between two tested materials.

Abstract: In lumbar disc herniation a possible functional problem in the ambulation is the Foot-drop syndrome caused by radicular nerve pinching. This causes a dramatic loss in gait cycle efficiency. In the rehabilitation process patients may benefit from wearing a foot orthosis that prevents them from falling and secondary injuries. Evidence in the literature suggests the important correlation between the optimal match of the forces produced during human gait and the rigidity of the constructive materials. The inherent rigidity of the materials plays an important role in determining its biomechanical functions. The paper proposes an experimental and numerical characterization of 3D printed ABS and PLA specimens using a universal traction-compression testing machine and a finite element method numerical simulation.

Abstract: Using antibiotic impregnated cement is an important mean to treat and prevent periprostetic joint infections. This complication requires for treatment important financial and technical resources. Adding antibiotics to orthopaedic cement may alter its mechanical properties with possible reduced time of prosthesis survival rate. This study analyze the mechanical properties of cement mixed with antibiotics in the operation room, which helps reducing costs and permit a more specific antibiotic local therapy. All tested antibiotics used in this study does not change the mechanical behavior of the orthopaedic cement when mixed in therapeutic doses, all alterations seems to be at a level below clinical significance. Mixing antibiotics in Orthopedic cement leads to minor decrease of the mechanical properties for cefazolin, cefuroxime, ceftazidime, meropenem and vancomycin and a mechanical significant decrease for gentamicin and clindamycin.