quebracho tannin wood adhesive in non formaldehyde approach has low autocondensation rate and needs more press time than formaldehyde-based wood adhesives to produce wood composites. in this study, boric acid was used to increase autocondensation rate of quebracho tannin adhesive to make poplar plywood. the main ingredients of the adhesives include quebracho tannin, naoh, hexamine, boric acid a...

OBJECTIVE To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding. METHODS Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etch...

new edible composite films formed from salep (orchis mascula) and 10%, 20%, and 30% (w/w) oleic acid were prepared by emulsification with the aim of improving the water vapor barrier and mechanical properties of the film. as oleic acid concentration increased up to 30% (w/w), oxygen permeability (27%), elongation at break (86%) and thickness (2%) of salep films increased significantly and the t...

The Rb+(K+) efflux of erythrocytes from six mammalian species was investigated in solutions of physiological and low ionic strength. A species dependent increase of the Rb+(K+) efflux in low ionic strength solution could be observed. The rate constant of Rb+(K+) efflux of erythrocytes in physiological ionic strength solution correlates with the content of arachidonic acid of the membrane phosph...

Introduction: One of the clinical problems in orthodontics is the bonding of brackets tocomposite restorations. The aim of this study was to evaluate the shear bondstrength of brackets bonded to composite restorations using Excite. Methods:Forty brackets were bonded to composite surfaces, which were embedded inacrylic resin. One of the following four protocols was employed for surfacepreparatio...

Aqueous complexation of Th(IV), U(IV), Np(IV), Pu(III/IV), and Ce(III/IV) with DTPA was studied by potentiometry, absorption spectrophotometry, and cyclic voltammetry at 1 M ionic strength and 25 °C. The stability constants for the 1:1 complex of each trivalent and tetravalent metal were calculated. From the potentiometric data, we report stability constant values for Ce(III)DTPA, Ce(III)HDTPA,...

The aim of this research was to study the effect of various water-to-cement ratio on the properties of pervious concrete. Tests were carried out to find the optimum water-to-cement ratio that gives a high compressive strength with acceptable permeability. The tests of fresh density, compressive strength at 7days, porosity and water permeability for four mixes of pervious concrete with various w...

We succeeded in expressing the recombinant full-length myosin Va (M5Full) and studied its regulation mechanism. The actin-activated ATPase activity of M5Full was significantly activated by Ca(2+), whereas the truncated myosin Va without C-terminal globular domain is not regulated by Ca(2+) and constitutively active. Sedimentation analysis showed that the sedimentation coefficient of M5Full unde...

Twin-roll casting AZ31 Mg alloy sheets have been fabricated by normal unidirectional-rolling, head-to-tail rolling, and clock-rolling, respectively. It has been demonstrated that head-to-tail rolling is the most effective to refine the microstructure and weaken the basal texture among the three rolling routes. Excellent integrated tensile properties can be obtained by the head-to-tail rolling. ...

The kinetics of acrylic acid (AA) solution polymerization was investigated by polymerizing 30 wt % aqueous AA solutions at pH values ranging from 2.2 to 9.9. The polymerization rate was determined with differential photocalorimetry and was found to be a strong function of the solution pH and the ionic strength. Although the polymerization rate decreased with increasing pH below pH 6.5, an incre...