Fate and efficiency of nitrogen fertilizers applied to wetland rice. II. Punjab,India

Two modified urea products (urea supergranules [USG] and sulfur-coated urea [SCU]) were compared with conventional urea and ammonium sulfate as sources of nitrogen (N), applied at 58 kg N ha^–1 and 116 kg N ha^–1, for lowland rice grown in an alkaline soil of low organic matter and light texture (Typic Ustipsamment) having a water percolation rate of 109 mm day^–1. The SCU and USG were applied at transplanting, and the whole dose of nitrogen was¹⁵N-labeled; the SCU was prepared in the laboratory and was not completely representative of commercial SCU. The SCU was broadcast and incorporated, whereas the USG was point-placed at a depth of 7–8 cm. The urea and ammonium sulfate applications were split: two-thirds was broadcast and incorporated at transplanting, and one-third was broadcast at panicle initiation. All fertilizers except the last one-third of the urea and ammonium sulfate were labeled with¹⁵N so that a fertilizer-N balance at flowering and maturity stages of the crop could be constructed and the magnitude of N loss assessed.At all harvests and N rates, rice recovered more¹⁵N from SCU than from the other sources. At maturity, the crop recovered 38 to 42% of the¹⁵N from SCU and only 23 to 31% of the¹⁵N from the conventional fertilizers, urea and ammonium sulfate, whose recovery rates were not significantly different. In contrast, less than 9% of the USG-N was utilized. Fertilizer nitrogen uptake was directly related to the yield response from the different sources. Most of the fertilizer N was taken up by the time the plants were flowering although recovery did increase up to maturity in some treatments.Analysis of the soil plus roots revealed that less than 1% of the added¹⁵N was in the mineral form. Between 20 and 30% of the¹⁵N applied as urea, SCU, and ammonium sulfate was recovered in the soil plus roots, mainly in the 0–15 cm soil layer. Only 16% of the¹⁵N applied as USG was recovered in the soil, and this¹⁵N was distributed throughout the soil profile to a depth of 70 cm, which was the lowest depth of sampling.Calculations of the¹⁵N balance showed that 46 to 50% of the urea and ammonium sulfate was unaccounted for and considered lost from the system. Only 27 to 38% of the¹⁵N applied as SCU was not recovered at maturity, but 78% of the USG application was unaccounted for. The extensive losses and poor plant recovery of USG at this site are discussed in relation to the high percolation rate, which is atypical of many ricegrowing areas.     

Effect of specific dietary fatty acids on lipogenesis in the livers and mammary glands of lactating mice

The effects of linoleic, linolenic and columbinic acids fed as 4% of a high carbohydrate (50% glucose) diet on the activities and the amounts of several enzymes associated with fatty acid synthesis in livers and mammary glands of lactating mice were compared with those for stearic and oleic acids. Fatty acid synthesis, measured in vivo, was significantly lower in livers of mice ingesting all 3 polyunsaturated fatty acids (PUFA), whereas in mammary glands synthesis was lower only in mice receiving columbinic acid. The activities of fatty acid synthetase (FAS) and acetyl CoA carboxylase were significantly reduced in liver by all 3 PUFA, as were activities of glucose-6-phosphate dehydrogenase, malic enzyme (ME) and citrate cleavage enzyme (CCE), also associated with lipogenesis. In mammary gland, on the other hand, the activities of these enzymes were unaffected by dietary PUFA. The tissue contents of FAS, ME and CCE, measured by rocket immunoelectrophoresis, were found to be significantly reduced in liver by linoleate, linolenate and columbinate but were not significantly altered in mammary gland. The decrease in hepatic lipogenesis observed was principally due to a decrease in the amounts of these enzymes induced by the dietary PUFA but the inhibition in mammary gland caused by columbinate could not be accounted for by a reduction in enzyme contents and therefore may be due to allosteric effects which occur when fatty acid synthesis is measured with³H₂O. The fatty acid composition in liver and mammary gland of dams and in liver and kidney of pups completely reflected dietary fatty acids. Columbinate made up ca. 20% of the total fatty acids in both tissues of the columbinic acid-fed mice and ca. 15% in the pup tissues. This suggests that columbinate is incorporated into milk lipids of dams and is easily absorbed by pups. The elevated ratios of 16/16∶1 and 18/18∶1 in liver and mammary gland of dams and liver and kidney of the pups from dams fed linoleate, linolenate and columbinate suggest that each of these polyunsaturated fatty acids in the diet can inhibit the activity of Δ9 desaturase.     

Quantitative studies on methyl ketone formation in butteroil: Effect of temperature

A quantitative study of the effect of various heat treatments on methyl ketone formation in butteroil was conducted. Methyl ketone formation was found to follow first-order reaction kinetics. The energy of activation was calculated to be approximately 26.55 kcal/mole. The ketones were formed in a fairly constant molar ratio approximating to the following C₁₅,2∶C₁₃,1∶C₁₁,1∶C₉,1∶C₇,2∶C₅,1. The temperature-time conditions had little or no effect on the ratio.     

A simple method for the quantitative isolation and resolution of unesterified fatty acids from fats and oils

The unesterified fatty acids (UFA) present in fats and oils are isolated cleanly and without the formation of detectable artifacts due to saponification. The lipid (≤0.5 g) dissolved in 5 ml of n-hexane is passed over a 300-mg bed of Celite impregnated with saturated, aqueous Na₃PO₄ so that the solution passes through the bed in 3–4 min. After the bed has been washed, the UFA are freed from their salts by pumping of HC1 vapor over the bed. The acids are eluted with CH₂Cl₂ and subsequently separated underivatized by gas liquid chromatography. The C₁₀ through C_18.3 acids are separated in <15 min. Recovery of the C₁₀-C_18∶0 and C_18∶1, C_18∶2 and C_18∶3 acids added to fatty acid-free fats and oils in several concentrations was nearly 100%     

Control of Leakage Resistance in Pb(Zr,Ti)O3 Thin Films by Donor Doping

Donor doping, with La and Nb, has been used successfully to improve the leakage resistance of Pb(Zr,Ti)O₃ (PZT) films. Donor doping of Pb(Zr_0.5Ti_0.5)O₃ films has led to an improvement in the leakage resistance of over 2 1/2 orders of magnitude at elevated temperatures (T 100°C). The effect on leakage resistance is the same for the A-site (La) and B-site (Nb) dopants. However, the improvement is only about 1 order of magnitude near room temperature. This temperature effect is due to an increase in the transition temperature from a low activation energy mechanism to a higher activation energy mechanism. Similar improvements in leakage resistance have also been obtained by increasing the Pb concentration in the starting solution, which implies that Pb vacancies are the dominant acceptor species in the undoped films. In addition, donor doping has been effective in improving the electrical breakdown strength at elevated temperatures. Consequently, donor-doped PZT films have been shown to be superior to undoped films for applications requiring high leakage resistance, such as decoupling capacitors.     

Orchestrated structure evolution: modeling growth-regulated nanomanufacturing

Orchestrated structure evolution (OSE) is a scalable manufacturing method that combines the advantages of top-down (tool-directed) and bottom-up (self-propagating) approaches. The method consists of a seed patterning step that defines where material nucleates, followed by a growth step that merges seeded islands into the final patterned thin film. We develop a model to predict the completed pattern based on a computationally efficient approximate Green's function solution of the diffusion equation plus a Voronoi diagram based approach that defines the final grain boundary structure. Experimental results rely on electron beam lithography to pattern the seeds, followed by the mass transfer limited growth of copper via electrodeposition. The seed growth model is compared with experimental results to quantify nearest neighbor seed-to-seed interactions as well as how seeds interact with the pattern boundary to impact the local growth rate. Seed-to-seed and seed-to-pattern interactions are shown to result in overgrowth of seeds on edges and corners of the shape, where seeds have fewer neighbors. We explore how local changes to the seed location can be used to improve the patterning quality without increasing the manufacturing cost. OSE is shown to enable a unique set of trade-offs between the cost, time, and quality of thin film patterning.