The wetlands of the Magela floodplain of northern Australia, which is the major sink for dissolved metals transported in the Magela Creek system, contain acid-sulfate sediments. The rewetting of oxidized acid-sulfate soil each wet season produces acidic pulses that have the potential to alter the bioavailability of sediment-associated metal contaminants. Acute toxicity tests (72-h mean lethal c...

In slightly acidic medium V(IV) forms with 4-nitrocatechol (NC) and 3-(4,5dimethyl-2-thiazol)-2,5-diphenyltetrazolium bromide (Thiazolyl Blue Tetrazolium, MTT) a well extractable into chloroform, intensively colored (ε405=3.5×10 l mol cm) 1:2:2 complex. The optimal conditions for extractive-spectrophotometric determination of V(IV) were found: pH 4.0-4.8, CNC= 2.9×10 mol l, CMTT= 1.6×10 4 mol l...

The system vanadium(IV) – 4-nitrocatechol (NC) – iodonitrotetrazolium chloride (INT) water – chloroform is studied. The optimum conditions for complex formation and extraction into chloroform are found: pH=3.9-4.5 and reagent concentrations at least 2x10 mol l NC and 1.2x10 mol l INT. The composition of the ternary complex is found to be V(IV):NC:INT = 1:2:2 with maximum absorbance at 350 nm. B...

The title electrodes were constructed by coimmobilizing the respective FAD oxidases on solid electrode surfaces with a poly(vinyl pyridine) polymer which was N-derivatized with bromoethylamine and Os(bpy)2Cl2. The redox-polymer-enzyme hydrogels were cross-linked on the electrode surface using poly(ethylene glycol) diglycidyl ether. As in the case of glucose oxidase, the redox polymer acts as an...

Prolonged ambulatory pH monitoring was performed on 89 patients with previous diagnosis of asthma (27 patients), chronic cough (28 patients), noncardiac chest pain (34 patients), and on 27 healthy control subjects. The extent of gastroesophageal reflux (GER) was determined using a catheter containing two antimony pH electrodes positioned 5 cm and 20 cm above the superior border of the manometri...

In this study, activated carbon synthesized from Aloe vera green wastes was used as a sorbent to remove 4-chlorophenol (4-CP) from aqueous solutions. The influence of contact time (0-100 minutes), pH (2-8), adsorbent dosage (1-9 g/l), and initial 4-CP concentration (10-60 mg/l) in batch system was investigated on the sorption. The sorbent was specified using scanning electron microscopy (SEM). ...

Lignite is an abundant carbon material with a variable surface structure and low cation density The introduction of metal (hydr)oxide phases has improved the anionic binding potential lignite. In this study, activated lignite (A−L), Ca2+−modified (Ca−L), (Ca−A−L) were synthesized to remove aqueous phosphate. was first (KOH: lignite, mass ratio, 3:1) at 750 ºC prepare A−L, improving its area by ...

Studies on LS-protein, the soluble double antigen of vaccinia, and on the degradation products L'S and L''S' have been made with electrophoresis and in the analytical ultracentrifuge. LS, which is homogeneous electrically and in the ultracentrifuge, has an isoelectric point at pH 4.8. At 4 degrees C. its partial specific volume is 0.72 cc./gm., and its diffusion constant is 1.50 x 10(-7) cm.(2)...

Introduction: Colloidal materials and suspended solids cause turbidity in water. To remove turbidity, clarification method is used that includes processes of coagulation, flocculation, and sedimentation. Due to the long duration of coagulation process, coagulant aids are applied. Despite the favorable efficiency of synthetic polyelectrolytes as a coagulant aid, due to their harmful effects on h...