Aldosterone 18-glucuronide in urine is hydrolyzed by adjusting the pH to 1.0 and allowing the mixture to stand overnight at room temperature. The free aldosterone is then extracted into dichloromethane, which is washed with carbonate to remove acidic compounds and evaporated. The residue is partitioned between a nonpolar organic phase and an aqueous phase, and the aldosterone oxidized to the 13...

A flow-through spectrophotometric bulk optode for the flow-injection determination of thiocyanate is described. As active constituents, the optode incorporates the lipophilized pH indicator 5-octadecanoyloxy-2-(4-nitrophenylazo)phenol and methyltridodecyl ammonium chloride, dissolved in a plasticized poly(vinyl)chloride membrane entrapped in a cellulose support. The optode is applied, in conjun...

One type of all-solid-state chloride sensor was fabricated using a MnO(2) electrode and a Ag/AgCl electrode. The potentiometric response of the sensor to chloride in synthetic concrete pore solutions was systematically studied, and the polarization performance was also evaluated. The results show a good linear relationship between the potential reading of the sensor and the logarithm of chlorid...

Hybrid fiber reinforced concrete (HFRC) consisting of two or more different types of fibers has been widely investigated because of its superior mechanical properties. In the present study, the effect of the addition of steel (0.25%, 0.5%, 0.75%, and 1% of concrete volume) and Polypropylene (0.2%, 0.4%, and 0.6% of concrete volume) fibers on the surface scaling resistance of concrete, depth of ...

Strains of P. oryxae were cultured, and crude filtrates of culture medium were prepared as described by Neufeld et al. (2). Protein was measured by the method of Lowry et al. (3). Assays--The increase in absorbancy at 320 rnp due to the formation of diphenyl disulfide was used to measure thiooxidase activity with thiophenol as substrate. The reaction rate was linear and proportional to enzyme c...

The chloride corrosion of reinforcing steel in reinforced concrete (RC) structures is a significant reason for premature deterioration and failure of RC structures in aggressive environments such as Persian Gulf region. This is one of the most important sources of engineering and economic problems in developed countries. So, the repair and maintenance of RC structures exposed to corrosive envir...

The relationship between fractal dimension of fine aggregates and the chloride resistance of concrete was investigated in this study. Both concrete and mortar specimens were cast. Concrete specimens were in the same mix design as the mortar specimens except for the coarse aggregates. The specimens were divided into different groups based on the gradation of the fine aggregates. The chloride res...

Enolase and ATPase are sensitive to fluoride. It is unclear whether this sensitivity differs for F-sensitive and F-resistant cells or for different types of fluoride. Permeabilized cells of the fluoride-sensitive strain Streptococcus mutans C180-2 and its fluoride-resistant mutant strain C180-2 FR were preincubated at pH 7 or 4 with NaF, the amine fluorides Olaflur and Dectaflur and amine chlor...

abstract statement of problem: the ph of the human abscess has been measured as low as 5.0. this low ph could potentially inhibit setting reactions, affect adhesion, or increase the solubility of root end filling materials hence affect the compressive strength. moreover, root end filling materials might expose or even mix with lidocaine hcl during periapical surgery. objectives: the aim of this...

This paper presents an experimental program on rapid chloride permeability test on lightweight concrete produced from oil palm clinker aggregates. Oil palm clinker is obtained from by-product of palm oil milling. Utilising oil palm clinker in concrete production not only solves the problem of disposing this solid waste but also help to converse natural resources. The parameter of investigation ...