Introduction: This study aimed to assess the color change of human teeth with artificial enamel white spot lesions (WSLs) after sandblasting with bioactive glass, resin infiltration, and microabrasion and to test color stability after pH cycling. Methods: Fifty extracted human mandibular first molars were randomly assigned into five groups: Sound, WSLs (untreated), and WSLs sandblasted with bioactive glass (Sylc), WSLs treated by resin infiltration (ICON), and WSLs treated by microabrasion (Opalustre), respectively. All specimens underwent a pH cycling procedure. The color parameters for each specimen were assessed using an Easyshade dental spectrophotometer at different time stages then the color changes (ΔE) were calculated. Results: The

New complexes of Cu (ll), Ni (ll), Co (ll), and Zn (ll) wi th 2-amino-5-p-Fiouro Phenyl 1, 3, 4-Thiadiazole have been synthesized. The products were isolated, studied and characterized by physical measurements, ie,(Ff-IR), UV-Vis and the melting points were determined. The new Schiff base (L) has been used to prepare some complexes. The prepared complexes were identified and their structural geometry were suggested

The dispersion of supported Pt and Pt–Ir reforming catalysts have been studied, after treatment with oxidative and reducing atmosphere. Methylcyclohexane dehydrogenation reaction in the absence of hydrogen was used as a test reaction. An attempt was made to relate the behavior of the catalysts upon subject to reaction, to the dispersion of the same type of catalysts upon treatment with similar atmosphere and temperatures which appeared in literature. The total conversion of reaction can be explained by a change in metal dispersion. Thus, methylcyclohexane dehydrogenation reaction appears to be a really “structure sensitive” reaction.

      The toluene yield increases as the oxidation temperature i

Polyaniline nanofibers (PAni-NFs) have been synthesized under various concentrations (0.12, 0.16, and 0.2 g/l) of aniline and different times (2h and 3 h) by hydrothermal method at 90°C. Was conducted with the use of X-ray diffraction (XRD), Fourier Transform Infrared spectra (FTIR), Ultraviolet-Visible (UV-VIS) absorption spectra, Thermogravimetric Analysis (TGA), and Field Emission-Scanning Electron Microscopy (FE-SEM). The X-ray diffraction patterns revealed the amorphous nature of all the produced samples. FE-SEM demonstrated that Polyaniline has a nanofiber-like structure. The observed typical peaks of PAni were (1580, 1300-1240, and 821 cm-1 ), analyzed by the chemical bonding of the formed PAni through FTIR spectroscopy. Also, tests

            This paper presents a sight about the chemical structure deformation of poly (ethylene-co-vinyl acetate) (EVA) samples according to the change ratio of rate constant values. Spectroscopy kinetics fluorescence curves are fitted for two characteristic wavelength domains of fluorescent intensities. The short wavelengths (320-400 nm) domain show spectra overlapping, while at long wavelengths (400-800 nm) domain spectra are arranged in regular for each specific accelerated aging time. The ratio of kinetics rate constant at long wavelengths to kinetics rate constant of short wavelengths is the criterion of the degree chemical structure deformation. Molar extrin

Tin dioxide (SnO2) were mixed with (TiO2 and CuO) with concentration ratio (50, 60, 70, 80 and 90) wt% films deposited on single crystal Si and glass substrates at (523 K) by spray pyrolysis technique from aqueous solutions containing tin (II) dichloride Dihydrate (SnCl2, 2H2O), dehydrate copper chloride (CuCl2.2H2O) and Titanium(III) chloride (TiCl3) with molarities (0.2 M). The results of electrical properties and analysis of gas sensing properties of films are presented in this report. Hall measurement showed that films were n-type converted to p- type as titanium and copper oxide added at (50) % ratio. The D.C conductivity measurements referred that there are two mechanisms responsible about the conductivity, hence it possess two act

This paper focused on the stone matrix asphalt (SMA) technology that was developed essentially to guard against rutting distress. For this procedure, fibers play a racy role in stabilizing and preventing the drain down problem caused by the necessity of high binder content coupled with their strengthening effect. A set of specimens with cylindrical and slab shapes were fabricated by inclusions jute, polyester, and carbon fibers. For each type, three contents of 0.25%, 0.5%, and 0.75% by weight of mixture were added by lengths of 5, 7.5, and 10 mm. The prepared mixtures were tested to gain the essential pertained parameters discriminated by the values of drain down, Marshall quotient, rut depth, and dynamic stability. It

Complexes of Au(III) ,Pd (II) , Pt (IV ) and Rh(III) with S – propynyle -2- thiobenzimidazole (BENZA) have been prepared and characterized by IR and UV- Visible spectral methods in addition to magnetic and conductivity measurements and micro – elemental analysis (CHN).The probable structures of the new complexes have been suggested.

This article includes designed and synthesized for bent-shaped liquid crystal molecules starting from 5,5-diethylpyrimidine-2,4,6(1H,3H,5H)-trione and two moles of chloroacetylchloride in N, N-dimethyl formamide (DMF) and triethylamine (TEA) to product compound [I] ,then reacted the later compound with two moles of 4-hydroxybenzonitrile to yield nitrile compound [II]. Likewise, reaction 5,5-diethylpyrimidine-2,4,6(1H,3H,5H)-trione and two moles of ethylchloroacetate with fused sodium acetate in ethanol to create an ester compound [III], and then the later compound was reacted with two moles of hydrazine hydrate in ethanol to obtained hydrazide acid compound [IV]. After that, the compound [IV] reacted with two moles of ethyl acetoacetate in

في هذا البحث تم تحضير المركبات المعدنية الجديدة لأيونات البلاتين (الرباعي) و الذهب (الثلاثي) مع ليكاند قاعدة مانخ جديد مشتق من السيبروفلوكساسين . تم استخدام المعقدات بعد ذلك كمصدر  لتحضير جزيئات                              عن طريق ترسيب المعقدات على مسام دقائق السيليكا النانوية.                                                                      Si/Au2O3 Si/PtO2  تم تشخيص الليكاند و معقداته