Variation of different metabolites and heavy metals in Oryza sativa L., related to chronic kidney disease of unknown etiology in Sri Lanka.

Chronic Kidney Disease of Unknown Etiology (CKDu) is a serious health problem in Sri Lanka. This disease is especially seen among lowland rice cultivators. Chemical stress factors such as pesticides and heavy metals can change the chemical composition and quantities of various metabolites in plants. Therefore, in this study phenolic compounds, free amino acid content and Chromium, Cadmium, Lead contents of rice grains were determined in CKDu prevalent areas. Furthermore, Chromium, Cadmium and Lead contents of cooked rice in CKDu prevalent areas were determined because they still use well water for cooking purposes and none of studies have been conducted to investigate the heavy metal contents of cooked rice. The total flavonoid contents of rice grains in highly CKDu affected areas are comparatively lower and has a significant negative correlation with Cadmium and Chromium contents in rice grains (P < 0.05). The Chromium, Cadmium and Lead contents of raw rice have been reduced during cooking process. Therefore, these heavy metal contents in cooking water are not sufficient to increase those heavy metal contents in cooked rice. However, the weekly intake of Chromium through cooked rice in CKDu prevalent area is higher than Povisional Tolerable Weekly Intake (PTWI) and weekly intake of Cadmium can exceed the PTWI with other foods rich with Cadmium. Therefore, this study suggested that total flavonoid content in rice grains is a important variation factor of CKDu prevalence and the chronic intake of Chromium and Cadmium contents may result kidney failure.

"Decarbonization" of an imino-N-heterocyclic carbene ligand via triple benzyl migration from hafnium.

An imino-N-heterocyclic carbene underwent three sequential benzyl migrations upon reaction with tetrabenzylhafnium, resulting in complete removal of the carbene carbon from the ligand. The resulting eneamido-amidinato hafnium complex showed alkene polymerization activity comparable to that of a precatalyst containing the intact iminocarbene ligand.

Access to 2'-substituted binaphthyl monoalcohols via complementary nickel-catalyzed Kumada coupling reactions under mild conditions: key role of a P,O ligand.

Two complementary Kumada coupling methods for the conversion of monotriflated 1,1'-binaphthalene-2,2'-diol (BINOL) into 2'-substituted binaphthyl monoalcohols under mild conditions are reported. A protocol using NiCl2(dppe), in combination with an improved preparation of the monotriflate, is effective for 1,1'-binaphthalene-2-ols containing unsubstituted or electron-poor aryl or benzyl 2'-substituents. An alternative procedure, using a potentially hemilabile-bidentate phosphinan-4-ol ligand, is superior for products containing neopentyl or electron-rich aryl 2'-substituents. The obtained binaphthyl alcohols represent potentially useful synthons for chiral ligands and auxiliaries.