ABSTRACT
Abstract This study evaluated the effect of adding the hydrophobic monomer 1,12 dodecanediol dimethacrylate (DDDMA) to experimental sealants with and without thermocycling on degree of conversion (DC), water sorption (WS), water solubility (WSB), color stability (ΔE), and micro-shear bond strength (μSBS). Five experimental and one commercially available sealant (Bisco - BIS) were tested. The experimental sealants were formulated by mixing different percentages of DDDMA monomers and urethane dimethacrylate (UDMA). The photoinitiator system was composed by camphorquinone (CQ) and tertiary amine 4-ethyl benzoate dimetilamiono (EDBA). Ethanol was used as a solvent. The experimental groups were named sequentially according to the monomeric content (DDDMA/UDMA): S40/40 (40/40), S50/30 (50/30), S60/20 (60/20), S70/10 (70/10) and S80/0 (80/0). Data were analyzed separately by one-way ANOVA, followed by Tukey's test (p<0.05). The values of DC ranged from 94.59% (S40/40) to 54.02% (S80/10). BIS showed the highest WS value (p<0.05) and S40/40, S50/30, S60/20 and S80/0 showed the lowest WS values of all tested sealants. WSB values ranged from 7.88 µg/mm3 (BIS) to 13.27 µg/mm3 (S70/10). The highest ΔE value was 11.05±2.88 for BIS and the highest μSBS value was found for S60/20. No significant difference was observed in bond strength between sealants and bovine enamel after thermocycling. Adding DDDMA to the composition of surface sealants can improve its performance, once the monomer increased the degree of conversion and the color stability.
Subject(s)
Humans , Cattle , Polymethacrylic Acids/chemistry , Polyurethanes/chemistry , Composite Resins/chemistry , Methacrylates/chemistry , Reference Values , Solubility , Surface Properties , Temperature , Time Factors , Materials Testing , Camphor/analogs & derivatives , Camphor/chemistry , Water/chemistry , Reproducibility of Results , Analysis of Variance , Dental Bonding/methods , Color , Dental Enamel/drug effects , Dental Enamel/chemistry , Shear Strength , Phase Transition , Ethanol/chemistry , Ethylenediamines/chemistry , PolymerizationABSTRACT
DNA storage is important to ensure integrity of DNA sample and maintain its availability while investigations. The best known condition for storage of DNA samples is by using Tris-EDT [TE]; as preservative agent, stored at -80[degree sign]C. A potential alternative to TE is trehalose which could stabilize any biological molecule at room temperature [RT]. Assessment of the optimal storage conditions which maintains quality of blood DNA samples with economical advantage. A case-control study using 8 groups of human blood DNA stored at 2 different temperatures [-80 [degree sign]C,RT] and preserved by using TE and trehalose. The effectiveness of storage conditions were tested at certain intervals [at set-up then after 3 and 6 month] using PCR assay of 18s ribosomal gene to evaluate DNA quality. DNA was assessed by running yield gels. PCR success rate were 43.8% and 62.8% using TE and trehalose respectively. After 6 months, PCR success rate were 25% for TE and 62.5% for trehalose [p<0.05]. The relative risk [RR] of poor quality associated with using trehalose is 0.4. Trehalose serves as an alternative to expensive freezer storage. It has a DNA protective effect which helps in preservation even trace DNA while judicial proceedings continue
Subject(s)
Humans , Blood Preservation , Acetates/chemistry , Ethylenediamines/chemistry , Trehalose/chemistry , Temperature , Time Factors , Comparative StudyABSTRACT
The rate of hydrolysis of N-N/-salicylidene-ethylenediamine [H2 salen] has been investigated in the pH range. 1.50-11.30, at 25 degree, in aqueous media containing 7% V methanol. It was observed that the rate was pH-dependent at values more basic than 9.20. The rate- limiting step, in basic media, was suggested to be the attack of hydroxide ions on the H2 salen as a keto-form. The pH-independent, reaction occurred at pH region 9.20-6.35. At pH values more acidic than 6.35, the hydrolysis rate became again pH-dependent, being correlated with the conversion of the substrate to its conjugate acid. Under these acidic conditions the predominant reaction was the attack of water molecules on the protonated substrate. Furthermore, the effects of transition metal ions viz. Ce [IV], Ce [III], Cu [II] and Zn [II] on the hydrolysis reaction rate have been examined and interpreted on the basis of formation of tricyclic chelate rings. Thermodynamic parameters were also determined and discussed
Subject(s)
Copper/chemistry , Zinc/chemistry , Hydrolysis , Thermodynamics , Ethylenediamines/chemistryABSTRACT
The synthesis and identification of certain metal chelates of nickel [II], cobalt [II], copper [II] and zinc [II] with some Schiff base lig and s derived from isatin with ethylenediamine and diethylenetriamine have been carried out. The mode of bonding and geometrical structures for the investigated metal chelates have been discussed in terms of microchemical analyses, molar conductivities, magnetic measurements, IR and electronic spectra. Ni [II] ion was found to coordinate octahedrally with diethylenetriamine bis [isatin] Schiff base lig and and possess square-planar arrangements with the other lig and s. The lig and s behaved as neutral tri-, tetra- and pentadentate towards the central metal ion. Copper [II] ion formed chelates of square-planar structures. Cobalt [II] chelates were suggested to have Oh and Td geometries whereas Zn [II] ion had coordinated tetrahedrally. Electrolytic nature was suggested for chelates