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UV curing is a photochemical process in which high-intensity ultraviolet light is used to instantly cure or ‘’dry’’ coatings, inks, adhesives and thin film technology. It has been around as a coating for wood, paper and as a clear coating via photolithography process on printed circuit boards PCBs or integrated circuit boards ICBs for years. It is fast becoming one of the most popular techniques in the paint and coatings industry. Most of the formulation use multifunctional acrylate monomers or oligomers or a mixture of them that crosslink under exposure to UV/EB radiations in a free radical process. We briefly present the advantages of EB vs. UV. A new type of formulation based on multifuctional monomer of dicyclopentadiene epoxy derivative with additional diluent as co-reactive solvent will be described and evaluated. This formulation differs from the acrylate one by the use of a cationic photoinitiator. The final product presents all the advantages of epoxy resins viz. better adherence, mechanical and thermal properties, compared to acrylate systems. Formulation has been optimized thanks to the differential scanning photocalorimetry DPC. This type of formulation is developed for additive digital manufacturing - 3D Printing (building layer by layer).

This paper presents the influence of component concentration for a class of polymeric blends with different concentration of PP (polypropylene) and PA6 (polyamide 6) and a constant concentration of additives: CaCO3, LDPE (low density polyethylene) and a compatibilizer POLYBOND® 3200. Mechanical properties has been investigated for four different test speeds, from 10 mm/min to 1000 mm/min. Young’s modulus performs in a band between 1500...1900 MPa, except for the value for PA6 at the lowest testing speed (v=10 mm/min), that is 1444 MPa. At high concentration of PA6, there were noticed voids in the longitudinal direction of the samples, forming large parallel ‘empty channels’, as the two polymers are immiscible. Except for values at low testing speed, the average values for tensile stress at break perform in a band of less than 8 MPa. The elongation at break is less than 10% for all materials, except for PA6 at the lowest testing speed, when a higher value was obtained. The lowest values were obtained for the blend with 20% PA6. For blends with 60% and 80% PA6, the difference between values, at the same testing speed, is the smallest. Energy at break has a slightly increase with the concentration of PA6. From the mechanical point of view, among the formulated blends, material D (with 80% PA6) is the most promising as has the highest values for stress and energy at break (11.8 J at v=10 mm/min and 9.6 J at v=1000 mm/min), but values are still less than those for PA6.

We analyze polymer dynamics in a fractal paradigm. Then, it is shown that polymer dynamics in the form of Schrödinger – type regimes imply synchronization processes of the polymers’ structural units, through joint invariant function of two simultaneous isomorphic groups of SL(2R) – type, as solutions of Stoka equations. In this context, period doubling, damped oscillations, self – modulation and chaotic regimes emerge as natural behaviors in the polymer dynamics. The present model can also be applied to a large class of materials, such as biomaterials, biocomposites and other advanced materials.

The research carried out within this paper addresses the issue of impact analysis with a spherical ball of an automobile fender, following two directions: the finite element method modeling of named part and situation, and experimental validation of the study mentioned beforehand. The part itself – car fender – is represented by a thermoset composite panel armed with Kevlar-Carbon fibers, while the analyzed situation is depicted as a Charpy/Izod test with a spherical ball on the specified component. The evaluation of named inquiry is performed in a virtual environment by means of FEA and verified accordingly within laboratory testing.

Dental sealants are important components of preventive dentistry. The aim of this clinical trial was to compare the effectiveness of an unfilled resin-based sealant and a carbomer-based dental sealant. 42 child patients with completely erupted inferior first molars and with diagnosed bruxism were included in the study. At 2 weeks, respectively 6, 12 and 18 months were evaluated the effectiveness of sealants after marginal deterioration, retention and the presence of caries. The results of the trial showed that unfilled resin-based sealant presented fewer modifications.

The work focuses some experimental aspects concerning the weight gain, differential scanning calorimetric (DSC), dilatometer analysis (DIL) and thermo - gravimetric analysis (TG/DTA) for a composite material, based on cotton tissue and unsaturated polyester resin noted MCTDBN and immersed in salt water with 5% NaCl for 90 days. Following these analyzes are emphasized the thermal expansion, temperature glass transition and thermal decomposition. Before of thermal analysis, the treated specimens were dried in an oven at temperature of 30°C for several days. The paper presents also the effect of salt solution treatment and comparative analysis between untreated and treated composites.

The aim of our study was to evaluate the deformation resistance of two palatal plate type connectors of removable partial dentures and to make a comparison between the reduced palatal plates and the large ones, in terms of bending resistance during function. We tested 10 maxillary class I Kennedy removable partial dentures made for real clinical cases and duplicated their connectors, 5 of each type. A Universal Loading Machine was used to apply a bilateral progressive force to the PM2-M1 area until the samples bended, recording the force value at which the first change occurred. The results were analyzed using the ANOVA method. For the reduced palatal plate group, the minimum bending force value was 1584 N, the maximum bending force value being 2920 N. For the large palatal plate group, the minimum bending force value was 3150 N, the maximum value being 3380 N. Statistical analysis of data using the ANOVA method shows that the results are statistically relevant, with a p value of 0,001031 (p[0,05). The results showed that decreasing the width of the palatal plate can have a significant effect on the deformation resistance of the major connector and can affect its rigidity; in clinical practice, these results can help dentists to use alternative appropriate design methods of increasing the rigidity of reduced palatal plates, in order to protect both the remaining structures and the acrylic components of the dentures during the years of its functioning.

Aortic valvulopathies, and especially aortic stenosis (AS), are the most common valvular disorders. Untreated, 50% of patients with severe AS will die within 2-3 years from the onset of symptomatology. The standard treatment consists in the surgical replacement of the aortic valve with mechanical or biological prosthesis. 40 patients were included in the study after replacement of the aortic valve with double disc mechanical prosthesis for severe degenerative AS. The disks of the prosthesis are made of pyrolytic carbon characterized by extreme hardness, which provides wear protection over the years. The ring is composed of a graphite substrate coated with pyrolytic carbon and attached to a suture collar made of polyethylene (polytetrafluoroethylene - PTFE) or polyester (Dacron® or Teflon®). This study evaluates mass regression and left ventricular mass index at three months and one year postoperatively. The regression of the left ventricular mass at 3 months after the surgery is 25.86%, and at one year after the surgery this regression was reduced - 15.11%. The regression of the mass of the left ventricle and especially the premature regression, correlated with the degree of hypertrophy of the left ventricle preoperatively, highlight the beneficial effect of the double disc mechanical prosthesis.

The current paper presents the advantages and disadvantages of the polypropylene mesh used for patients who underwent abdominoplasty associated with the treatment of abdominal wall defects. The study was based on data obtained from 64 patients who benefited from abdominoplasty associated with the surgical treatment of abdominal parietal defects, such as: hernias, eventrations and diastasis. The results of the research show that the use of the polypropylene mesh is associated with an increased resistance of the rectus abdominis sheath plication, the reduction of the postoperative complications rate and the improvement of the patients’ satisfaction regarding the aesthetic result of the surgical intervention.

Objective of this study was to develop and validate HPLC-UV method for detection of LTG in lipid nanoformulations. HPLC-UV method was developed according to ICH Q2(R1) guidelines. Central composite design was used effectively to optimize and study the effect of buffer strength, flow rate, pH of buffer and mobile phase composition on responses such as tailing factor, peak area, retention time and number of theoretical plates. The 30 mM ammonium formate buffer and acetonitrile (in the ratio 65:35 %v/v) was used as mobile phase in the study. The mobile phase was delivered at the flow rate of 1.0 mL/min. The detection of buffer was performed at 256 nm using UV detector. The drug entrapment of prepared formulation was also determined using developed HPLC method. Retention time of lamotrigine was found to be 3.844 min. The coefficient of determination (r2) value from linearity was found to be 0.9982. Percent relative standard deviation value of precision was found to be within the acceptable range. The estimated LOD and LOQ were found to be 9.07 ng/mL and 27.48 ng/mL, respectively. Drug entrapment of prepared lipid nanoformulation was found to be 73.44 ± 6.65%. The results conclude that the developed analytical method is simple, precise, sensitive, fast and reproducible. Applications of developed method for determination of drug entrapment in prepared lipid nanoformulation confirmed that the developed analytical method is suitable for estimation of lamotrigine in lipid nanoformulations.