Forty elements in 21 coastal marine sediment samples collected duringthe second Antarctic scientific expedition from 18 different sites of Brekilenarea located at the coast of Antarctica were analysed by instrumental neutronactivation analysis (INAA) to detect eventual pollution. Radio-assay schemesfor three sets of elements after neutron irradiation and cooling were evolvedto avoid matrix effects. Data have been compared with those for sedimentsof various stations at Antarctica and two other regions in different continents.Lower concentration of certain elements in the Antarctic sediments reflectsless environmental exposition. Enrichment factors (EF) were calculated forall the elements using the earth crust as reference matrix, based on elementalvalues by MASON, TAYLOR and WEDEPOHL which show a normal pattern near to unityexcept for Ag and Br. The data obtained could also serve as a reference pointfrom which changes in the global environment can be studied. The quality assuranceof data was performed using standard reference materials (SRMs) of a similarmatrix (IAEA Marine Sediment SD-M/TM and Chinese Marine Sediment GBW 07313).
The extraction of PAN chelates of the group IB, IIB and IIIA–VA elements from aqueous solutions of pH 1–10 into chloroform
has been studied radiochemically. Re-extraction studies have been made to strip the metal ions from the organic phase into
aqueous solutions of KCN, HClO4 and buffer solutions. The effects of certain masking agents on the extraction of these elements have also been studied. The
extraction curves indicate the possibilities of devising group chemical separation procedures for use in activation analysis.
The use of a naturally available Lateritic Soil (LS) for the removal of mercury from industrial effluents has been investigated. Adsorption of Hg on LS from aqueous solution is reported, describing the effect of equilibration time, hydrogen ions, adsorbent and adsorbate concentration. The contact time required is less than two minutes and adsorption capacity is 15 g/kg.
Solvent extraction of Cr(VI), Mo(VI), W(VI) and Hf(IV) with 1-phenyl-3-methyl-4-caproyl-pyrazolone-5 (PMCP) in methyl isobutylketone
(MIBK), xylene and chloroform (CHCl3) from mineral acid solutions was studied. Chromium(VI) is not extracted from any of the acids studied (HCl, H2SO4 and HClO4). Molybdenum(VI) is quantitatively extracted by the reagent in xylene and CHCl3 from HClO4 and HNO3 solutions. It is also extracted quantitatively by the reagent in MIBK from HCl, HNO3 and H2SO4 solutions but the participation of the diluent as extractant is considerable. Tungsten(VI) is quantitatively extracted in
xylene from 9M HClO4 solution. MIBK used as diluent also affects its extraction with PMCP. Hafnium(IV) is not extracted from H2SO4 solutions while it extracts more than 99% at 3M HNO3 and above. The extracted species likely are: MoO2(PMCP)2, WO2(PMCP)2 and Hf(PMCP)4, respectively.
Neutron activation analysis has been used for the simultaneous determination of Cu, Mn, Zn and Na in plant materials. The
heterocyclic dye PAN has been applied as a chelating agent to achieve the group chemical separation of Mn, Cu, Ni and Zn.
Various factors which affect the formation and extraction of the PAN-metal chelates have been studied and optimized, using
suitable aqueous solutions to selectively strip these elements from the organic phase. This procedure has been applied to
the determination of these elements in ‘Bowen’s Kale’ and U.S. NBS Citrus-leaves and Tomatoleaves samples.
The extraction of group IB, IIB and IIA-VA elements with 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazolone-5 in chloroform has
been investigated as a function of pH. The stripping of metal ions into solutions of KCN, HClO4 and appropriate pH buffers has been studied. The masking effects of cyanide, citrate, iodide, thiosulphate and thiourea on
the extraction have been examined. Selective group and individual separations have been proposed on the basis of pH control,
masking effects and back-extraction.
This study investigated whether kisspeptin-10 (KP-10) prevents diabetic rhesus monkeys from insulin-induced hypoglycemic shock.
Materials and methods
Thirty-six adult male rhesus monkeys were used, six in each group. Diabetes was induced with streptozotocin (45 mg/kg b.w.; single dose i.v.). Groups were as: saline control, insulin alone, pre-insulin (treated with KP-10, 30 min before insulin), post-insulin (treated with KP-10, 30 min after insulin), treated with premix dose of KP-10 (50 μg) and insulin, and the group treated with the kisspeptin antagonist P234 (50 μg). Following an overnight fast, each animal was subjected to respective treatment, and blood glucose concentrations were recorded every 30-min interval for 3 h.
Intergroup comparisons demonstrated that treatment with KP-10 prior to insulin administration and kisspeptin–insulin premix treatment allowed blood glucose levels to rise to significantly higher levels (p < 0.001) by 180 min in diabetic and healthy animals compared to treatment with insulin alone. However, intragroup comparisons revealed a significant decrease in blood glucose level in diabetic animals only. Treatment with P234 antagonist followed by insulin administration abolished the preventive action of kisspeptin, whereby blood glucose decreased significantly (p < 0.001) in both diabetic and healthy animals. KP-10 post-insulin treatment, however, remained ineffective and led, instead, to significantly decreased glucose concentrations by 180 min in both diabetic and healthy animals when compared to animals treated with insulin alone.
KP-10 bears therapeutic potential to prevent hypoglycemic shock that may sometimes occur during intensive insulin therapy. Several pharmacological aspects of its interaction with insulin and other drugs, however, remain to be investigated.
An instrumental neutron activation analysis method based on the measurement of239Np has been developed for the determination of uranium in ores. The samples after 5 sec irradiation were cooled for 3 days
and the gamma-ray spectra were measured with a 30 cm3 Ge(Li) detector. The precision and accuracy of the proposed method were determined by analysing IAEA Standard Uranium Ore
A routine procedure has been developed for the simultaneous determination of uranium and thorium in high concentration thorium ores. INAA is used to determine the uranium and thorium concentration. However, for very low concentrations of uranium a radiochemical procedure based on the use of NPy/benzene as an extractant has to be employed. The precision and accuracy of the method has been determined by analyzing IAEA and NBL standard thorium/uranium ores.