The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging.
Oil palm fronds (OPF) were used to prepare activated carbon (PFAC) using physiochemical activation method, which consisted of potassium hydroxide (KOH) treatment and carbon dioxide gasification. The effects of the preparation variables, which were activation temperature, activation time and chemical impregnation ratios (KOH: char by weight), on the carbon yield and bentazon removal were investigated. Based on the central composite design (CCD), two factor interaction (2FI) and quadratic models were, respectively, employed to correlate the PFAC preparation variables to the bentazon removal and carbon yield. From the analysis of variance (ANOVA), the most influential factor on each experimental design response was identified. The optimum conditions for preparing activated carbon from OPF were found as follows: activation temperature of 850 degrees C, activation time of 1h and KOH:char ratio of 3.75:1. The predicted and experimental results for removal of bentazon and yield of PFAC were 99.85%, 20.5 and 98.1%, 21.6%, respectively.
The present study was aimed at modifying the original formulation of Commercial Eugon agar (CEA) to develop a new H. pylori growth medium. Initial studies were carried out to determine the number of H. pylori colonies recovered on in-house H. pylori agar (IHPA), IHPA without L-cysteine and sodium sulfite (IHPA-NC), IHPA without L-cysteine (IHPA-C), IHPA without sodium sulfite (IHPA-N) and CEA as the control. Significant differences (P < 0.001) in the number of colonies recovered were observed between IHPA-N, IHPA-NC and IHPA-C. Incorporation of sodium sulfite decreased the number of colonies recovered, indicating that sodium sulfite was inhibitory to H. pylori growth. Removal of L-cysteine reduced the number of colonies recovered, suggesting that L-cysteine is necessary for the growth of H. pylori. In the subsequent study, incorporation of K(2)HPO(4) further increased the number of colonies recovered compared with IHPA-N (P < 0.001), and 0.25% (w/v) of K(2)HPO(4) yielded the highest numbers of colonies (P < or = 0.04). Finally, thirty other H. pylori clinical isolates were evaluated for their growth in the IHPAP-N, a new medium consisting of 1.5% (w/v) pepticase, 0.5% (w/v) peptone, 0.4% (w/v) sodium chloride, 0.03% (w/v) L-cysteine, 0.55% (w/v) dextrose, 0.25% (w/v) K(2)HPO(4) and 1.5% (w/v) agar. The number of colonies recovered in IHPAP-N was significantly (P < 0.005) higher than that of CEA. IHPAP-N with 0.25% K(2)HPO(4) and without sodium sulfite were adequate solid media for the growth of H. pylori.
A polystyrene (PS)-anchored Pd(II) metal complex was synthesized on cross-linked polymer by heating a mixture of chlorometylated polystyrene with phenyldithiocarbazate and carbon disulfide in the presence of potassium hydroxide (KOH) in dimethylformamide (DMF). The reaction mixture was heated at 80 °C to form the corresponding phenyldithiocarbazate-functionalized polymer. Then, it was treated with bis(benzonitrile)palladium(II) chloride. The properties of dark colored polymer, impregnated with the metal complex was then characterized by various spectroscopic technique such as Fourier Transform Infrared (FTIR), Scanning Electron Microscopy/Energy Dispersive X-ray (SEM/EDX), CHNS elemental analysis, BET surface area, X-ray Diffraction (XRD), Thermogravimetric (TGA) and Inductively Coupled Plasma-Optical Emission (ICP-OES) spectroscopy.
Proteases in ginger rhizome have the potentials in industrial applications. This study was conducted to extract and characterize the proteolytic enzyme from ginger (Zingiber officinale Roscoe). Ginger protease (GP) was extracted from ginger rhizome by homogenization with 100 mM potassium phosphate buffer pH 7.0 containing 10 mM cysteine and 5 mM EDTA which were found to be the most efficient extraction buffer and stabilizers. After centrifugation at 10,500 x g, protein in the crude extract was precipitated using 60% ammonium sulfate following which the precipitate was redissolved in 50 mM potassium phosphate buffer pH 7.0, dialyzed and then lyophilized. The extraction method yielded 0.94% (w/w of fresh weight) of GP with a specific activity of 27.6 ± 0.1 Unit/mg protein where 1 Unit is defined as the amount of protease causing an increase in absorbance by 1 unit per minute using azocasein as the substrate. Results show that the GP was completely inhibited by heavy metal cations i.e. Cu2+and Hg2+, and a thiol blocking agent or inhibitor, n-ethyl maleimide (NEM), indicating that GP is most probably a cysteine protease. The enzyme has an optimum temperature at 60⁰C and the optimum pH ranged between pH 6 to 8. Monovalent cations (K+ and Na+) have no significant effect on activity of GP, but divalent and trivalent cations showed moderate inhibitory effect. Detergents such as sodium dodecyl sulfate increased the activity of GP while Tween 80 and Tween 20 slightly reduced the activity.
The land area of Tanah Putih, Gua Musang, Kelantan (Malaysia) is well-known for its wealth in industrial mineral resources, especially aluminosilicate of feldspar and mica. Natural feldspar and mica were physicochemically characterized with regard to X-ray diffraction (XRD), nitrogen sorption analysis and transmission electron microscopy (TEM) techniques for qualitative and quantitative identification of feldspar and mica. They show a good crystallinity, high surface area and uniformity of mesoporous structures. For the purpose of this experiment, the aluminosilicate of feldspar was modified either by acid treatment, or grafting the silanol groups present with various functional groups including aminopropyl-, octyl-, vinyl-, mercapto- and glycidoxy-triethoxysilanes, or activation of pre-treated support with glutaraldehyde. These support derivatives were used for further utilization in the immobilization of lipase from Candida rugosa and resulted in various interaction mechanisms between enzyme and introduced supports. It seemed that the features of the functionalized feldspar surfaces provide a preferable environmental host to enable the adsorption of lipase via interfacial adsorption method. Lipase immobilization onto feldspar support were further confirmed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray microanalysis (EDX), transmission electron microscopy (TEM) and infra-red spectroscopy (FTIR) techniques. Enhancement of protein loading (up to 8.22 mg protein/g support) and immobilization yield (up to 78%) were shown by modified feldspar-lipase derivatives compared to unmodified feldspar support.
As a novel method of purification, an aqueous organic phase system (AOPS) was employed to purify pectinase from mango waste. The effect of different parameters, such as the alcohol concentration (ethanol, 1-propanol, and 2-propanol), the salt type and concentration (ammonium sulfate, potassium phosphate and sodium citrate), the feed stock crude load, the aqueous phase pH and NaCl concentration, were investigated in the recovery of pectinase from mango peel. The partition coefficient (K), selectivity (S), purification factor (PF) and yield (Y, %) were investigated in this study as important parameters for the evaluation of enzyme recovery. The desirable partition efficiency for pectinase purification was achieved in an AOPS of 19% (w/w) ethanol and 22% (w/w) potassium phosphate in the presence of 5% (w/w) NaCl at pH 7.0. Based on the system, the purification factor of pectinase was enhanced 11.7, with a high yield of 97.1%.