Effect of Surface Polishing on Nano-Hardness and Elastic Modulus of Different Resin Composites after Immersion in Alcoholic Medium

There has been a great tendency toward using resin composite in dentistry and exploring nano-hardness, elastic modulus, and effect of polishing on its mechanical properties after its artificial ageing. This study aimed to evaluate the effect of surface polishing of four different resin composites on their nano-hardness and elastic modulus. This effect was tested right after light curing of composite resin and after its artificial ageing (immersion in alcoholic medium). Nanoindentation test preparations, surface roughness, surface hardness, and scanning electron microscope were conducted across the four different resin composites: Clearfil AP-X (APX), Estelite Sigma Quick (ESQ), Beautifil II (BE2), and FiltekTM Supreme Ultra Universal restorative (FSU). We found that difference in fillers load and particle size are amongst the factors influencing hardness and modulus of elasticity. The APX is the highest in term of hardness due to fillers load and size while the ESQ is the lowest because all fillers in nano size and distributed homogenously. The significance of surface polishing of the studied resin composite restorations was highlighted. Future research may focus on exploring survival rate of polished and non-polished composite surfaces with emphasis on measuring degree of conversion and impacts of polished and non-polished surfaces on the individuals’ oral health quality of life.

MoO3 Nanoparticles as an Efficient Catalyst for the Synthesis of Pyrazoles in Aqueous-alcoholic Medium at Room Temperature

We have successfully explored the potential MoO3 nanoparticles as a heterogeneous catalyst for the cyclocondensation of hydrazines/hydrazides with 1,3-dicarbonyl compound in aqueousalcoholic medium at room temperature. The present method has been developed using green chemistry measures and offers a range of N-substituted pyrazoles with moderate to excellent yields. Utilization of non-toxic catalyst, wide substrate scope and environmentally benign reaction medium are the important features of the developed protocol. Interestingly, MoO3 nanocatalyst can easily be recovered from the reaction mixture and showed excellent reusability with a modest change in product yield. We have reported herein the synthetic pathway with less disastrous effect in the atmosphere.

Researches Concerning Chemical Modifications of Hair Keratin

The work presents chemical procedures used to obtain a film or a hydrogel after hydrolyze treatment of hair at the temperature of 150oC and the pressure of 4.9 atm. In order to obtain the hydrogel, this treatment is followed by a stage of oxidation with hydrogen peroxide, and a stage of reduction with Na2S2O4 or, in another variant, a stage of oxidation with hydrogen peroxide and a treatment with NaOH in alcoholic medium, to form natrium cationic groups. The protein chains with sulphonic groups and natrium cations determine opposite electrostatic interactions, with the formation of a polymer loop that incorporate water. The evaluation of formed hydrogel was carried out by determining the swelling degree. We have used optical and SEM photomicrographs to determine morphological organization, and EDAX micropictures for chemical modifications. A cellulose film realized by growing Gluconoacetobacter xylinus bacteria was used as control sample.

Synthesis and physicochemical research of some 2-((5-((theophylline-7'-yl)methyl)-4-R-4H-1,2,4-triazole-3-yl)thio)acetohydrazide ylidenderivatives

The rapid development pace of the pharmaceutical science constantly increases the demand for new kind of medicine featured with high biological activity and non-toxicity at the same time. Setting the aim to enlarge the amount of scientific findings in the domain of biologically active substances, 1,2,4-triazole and theophylline were used as the starting material. These compounds form the basis for the majority of drugs, such as diuretics, antifungal and antibacterial medicaments. The combination of heterocycles put under research demonstrate a repeated probability increase in the variety of activities. Therefore, the relevance of the following study is determined by valuable properties of these substances. Besides that, the presence of a hydrazide element accounts for a high probability level of antimicrobial, particularly anti-tuberculosis activity. In order to identify optimal conditions for the synthesis and physicochemical property research, 2-((5-((theophylline-7'-yl)methyl)-4-R-4H-1,2,4-triazole-3-yl)thio) acetohydrazide ylidenderivatives were obtained. The process of production was carried out through long chain reactions, using the sodium salt of theophylline as a substrate. The conversion is well known being described in many papers. Hydrazide was taken as the starting compound. It was dissolved in water-alcoholic medium while separately, aldehyde was dissolved or mixed in ethyl alcohol as well. The resulting solutions were decanted. The precipitate formed immediately or after a certain period of time, which is likely due to the state of matter of the starting aldehyde. 10 compounds (light-yellow crystalline materials with sharp melting point) were synthesized after that. Their structures and physicochemical properties were confirmed with modern methods of analysis. It is established that the reaction proceeds rapidly with a yield of 77‒95% in water-alcoholic medium at a temperature of about 80 °C.

Synthesis and characterization Studies of Metal Complexes with Schiff base derived from 4-[5-(2-hydoxy-phenyl)-[1,3,4-oxadiazol-2-ylimino methyl]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one

New metal complexes of the ligand 4-[5-(2-hydoxy-phenyl)-[1,3,4- oxadiazol -2-ylimino methyl]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (L) with the metal ions Co(II), Ni(II), Cu(II) and Zn(II) were prepared in alcoholic medium. The Schiff base was synthesized through condensate of [4-antipyrincarboxaldehyde] with[2-amino-5-(2-hydroxy-phenyl-1,3,4- oxadiazol] in alcoholic medium . Two tetradentate Schiff base ligand were used for complexation upon two metal ions of Co2+, Ni2+, Cu2+ and Zn2+ as dineucler formula M2L2.4H2O. The metal complexes were characterized by FTIR Spectroscopy, electronic Spectroscopy, elemental analysis, magnetic susceptidbility measurements, and also the ligand was characterized by 1H-NMR spectra, and mass spectra. The Structures of complexes were proposed from the measurements.