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[en] Influence of azolla on rice growth treated with and without fertilizer. An experiment to investigate the influence of azolla on growth of rice treated with and without N fertilizer has been carried out in the rainy season 1984/1985 at the Muara Experimental Station, Bogota. Rice variety used in this experiment was Atomita I. Eight treatments employed in this experiment were treatments without azolla and N fertilizer, with azolla alone, with N fertilizer alone, and a combination of azolla and N fertilizer used was urea labelled with 5% 15N atom excess. Parameters observed were: dry weight, total-N and N-derived from fertilizer in rough grain, straw and plant. Data from this experiment indicated that azolla was able to produce similar yield of rough grain, straw and plant with those produced by N fertilizer applied at a rate of 90 kg N/ha. These data were much higher compared to N fertilizer applied at a rate of 30 and 60 kg N/ha. The same trend was found in yield of N. It turned out that apparently azolla is effective to increase rice production. (author). 3 figs., 8 refs
[en] Data on the synthesis and properties of aza- and diazacrown compounds containing a phenyl group at a nitrogen atom or an o-phenylene fragment annelated to the macrocycle are generalised. The functional derivatives of these compounds and their heteroanalogues with O, S and N atoms are considered.
[en] The determination of a very large, inverse, secondary deuterium isotope effect in the photorearrangement of 1-iminopyridinium ylides provided the basis for a general criterion and a method of detecting the occurrence of thermally activated steps in a photoreaction process. This large isotope effect is taken to be indicative of a thermal transition state in which the carbon seat of rearrangement is increasing its covalency. The structure of an intermediate ylide supported by the kinetic isotope effect data is proposed
[en] A method is described for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R1R2C(OSOCl)C/sub n/, R1R2C(Cl)C/sub n/ and (R1R2C(C/sub n/)O)2SO wherein R1 and R2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art
[en] Data on the synthetic methods, reactivities, biological activities and other practically important properties of 1,8-naphthyridine derivatives published over the last 15 years are analysed.
[en] The degradation characteristics of clopyralid irradiated by electron beam (EB) was studied in aqueous solutions. The effects of factors, such as initial clopyralid concentrations, addition of radicals scavenger, initial solution pH and addition of H2O2, were investigated on clopyralid degradation efficiency and mechanism. It was found that the EB-radiolysis was an effective way to degrade clopyralid and its degradation rate decreased with the increasing of substrate concentration. In the investigated initial concentrations range of 100-400 mg L-1, the radiolytic degradation of clopyralid followed a pseudo-first kinetic order. The results from addition of radicals scavenger indicated that both ·OH and eaq- played significant roles in the degradation of clopyralid. Furthermore, the alkaline condition and addition of H2O2 (<10 mM) in the solution also slightly enhanced the efficiency of clopyralid degradation. The ion chromatography analysis showed that some organic acids (formic acid, acetic acid and oxalic acid) were formed, while the completely dechlorination of the substrate was achieved and organic nitrogen was recovered in the form of ammonium and nitrate ions during the irradiation process. (author)
[en] The results of a heavy-atom isotope effects study of the photoactivated reaction of a carbon-13 labelled 1-iminopyridium ylide are reported. The experimental results correspond to an inverse isotope effect which indicates greater bonding preference for the heavier isotope