Lowland rice response to potassium fertilization and its effect on N and P uptake

Not much is known about the response of lowland rice to K fertilization under Brazilian conditions. A field experiment was conducted during four consecutive years to determine the response of three lowland rice (Oryza sativa L.) cultivars to K fertilization on a Low Humic Gley soil. In the first two years, K was broadcast at rates of 0, 42, 84, 126, and 168 kg K ha^–1. In the last two years K rates were reduced to 0, 25, 50, 75, and 100 kg K ha^–1 and applied in a band. Potassium significantly (P < 0.01) increased grain yields but the response varied from cultivar to cultivar and year to year. Yield responses to K fertilization were superimposed on a general trend of increasing grain yields across the four growing seasons. Mean grain yields increased 14.3% with broadcast application of K in the first two years and 10.4% with banded application of K in the last two years when compared to the control treatments. Extractable soil K increased with K application rate and decreased with soil depth. Potassium was rapidly removed from the soil and yearly broadcast or banded application of K can be expected to result in a significant increase in grain yield of lowland rice in these soils.     

Quantitative31P nuclear magnetic resonance analysis of the phospholipids of erythrocyte membranes using detergent

³¹P Nuclear magnetic resonance (NMR) spectra of human erythrocyte lysates dissolved in sodium cholate were acquired. The narrow resonances of phospholipids were mostly well resolved, allowing identification and accurate quantitative analysis of phospholipid classes of the erythrocyte membranes. The ether-linked phosphatidylethanolamine components of the erythrocyte membranes were identified, based on the removal of plasmalogens by acidolysis and of diacyl phospholipid species by degradation using phospholipase A₁. It was also shown that the introduction of double bonds on the acyl chains of phosphatidylcholine shifted the³¹P NMR resonances to lower frequencies. Quantitative analyses of phospholipids from the spectra were based on their apparent molar concentrations. The recoveries of phospholipids from erythrocytes were significantly higher than those using conventional extraction procedures.     

Separation and identification of phenolic acids and related compounds by gas chromatography and fourier transform infrared spectroscopy

Phenolic acids and related compounds were separated by gas chromatography using three separate columns. One of these columns was coupled to a Fourier transform infrared spectrometer. The trimethylsilyl derivatives could be separated and identified by comparing the relative retention times of the three different columns. However, where there was overlap, the accompanying infrared data clearly distinguished between the questionable derivatives, thus enabling characterization of all derivatives.The use of trade, firm, or corporation names in this article is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the U.S. Department of Agriculture or the Forest Service of any product or service to the exclusion of others that may be suitable.     

Chromate leaching from inhibited primers: Part I. Characterisation of leaching

Leaching and characterisation studies have been undertaken on two chromate-inhibited epoxy polyamide primers. Leaching was carried out in 5% (w/v) NaCl solutions at different pH values (1, 3, 5 and 7) and the amount of Cr released into solution was monitored over time. Cr release was initially high, but as the immersion time increased the leaching from the primers slowed. Prior to and after immersion, the primers were characterised by a number of techniques including electron microprobe analysis, X-ray microdiffraction, Raman spectroscopy, and positron annihilation lifetime spectroscopy. The unexposed primers were found to contain the inorganic phases SrCrO₄, BaSO₄ and TiO₂ (anatase or rutile). Upon immersion, water uptake by the primers was observed, together with a decrease in the amount of SrCrO₄ in the primers. These studies provide insights into the mechanism of chromate leaching from inhibited primers.     

Effect of DAG on milk fat TAG crystallization

The effect of milk fat and standard DAG on the crystallization behavior of milk fat TAG (MF-TAG) was investigated. When milk fat DAG were added to MF-TAG at the 0.1 wt% level, crystallization was delayed. Racemic purity was shown to be an important factor in the ability of DAG to influence TAG crystallization. Only sn-1,2 isomers of blends of MF-TAG with 0.1 wt% of the racemic mixtures of dipalmitin and diolein increased the activation free energy barrier to MF-TAG nucleation (ΔG _c ) and delayed the subsequent crystallization process by increasing the crystallization induction time (τ_SFC) determined from solid fat content-time measurements. Although crystallization kinetics were affected, the properties of the resulting network structures remained unchanged upon addition of milk fat minor components at the 0.1 wt% level     

Toxicity of nitro compounds fromLotus pedunculatus to grass grub (Costelytra zealandica) (Coleoptera: Scarabaeidae)

Crude extracts of root of the forage legumesLotus pedunculatus andCoronilla varia (crownvetch) were toxic when administered orally to 3rd instarCostelytra zealandica larvae. A group of 3-nitropropanoyl-d-glucopyranoses was isolated from active fractions of the crude extracts. These toxins, some of which were already known fromC. varia, have not previously been reported fromL. pedunculatus. The compounds were present in root tissue of this species at a concentration of about 1% dry weight. They include the triester karakin and the diesters coronarian and cibarian, all of which were toxic to larvae ofC. zealandica at levels which could account fully for the activity of the crude extracts.     

Nucleation and growth of anodic oxide films on bismuth—I. Cyclic voltammetry

The early stages in the formation of a continuous anodic layer of bismuth oxide on a solid bismuth electrode, in the pH range 5–14, were studied. The oxide covered the surface by the simultaneous thickening and spreading of patches. The metal surface was classified into two different areas with different overvoltage for oxide nucleation. The ratio of the two areas varied according to the history of the surface.The thickening of the newly formed layer (final thickness ～20 nm) followed the high-field growth law i = $\text{A}$exp(B$\text{E}$) where $\text{E}$ is the field in the oxide layer, with B = (2.0 ± 0.5) × 10^?6 V^?1 cm. This value of B gives an activation distance for high-field ion transport of 0.2 nm, comparable to the radius of a lattice site and much smaller than that obtained previously, for much thicker films.Dissolution of the film, giving breakdown of the oxide layer and pitting of the metal, occurred for pH<8. The thickness of the anodic film was thus limited to only 4 nm at pH 5.Cathodic reduction of the anodic oxide resulted in a porous metal surface. The current—voltage curve for the reduction often had a complex shape, which was related to the morphology of the original anodic layer.     

Shape memory polymers based on uniform aliphatic urethane networks

Aliphatic urethane polymers have been synthesized and characterized, using monomers with high molecular symmetry, to form amorphous networks with very uniform supermolecular structures, which can be used as photo‐thermally actuable shape memory polymers (SMPs). The monomers used include hexamethylene diisocyanate (HDI), trimethylhexamethylenediamine (TMHDI), N,N,N′,N′‐tetrakis(hydroxypropyl)ethylenediamine (HPED), triethanolamine (TEA), and 1,3‐butanediol (BD). The new polymers were characterized by solvent extraction, NMR, XPS, UV/VIS, DSC, DMTA, and tensile testing. The resulting polymers were found to be single phase amorphous networks with very high gel fraction, excellent optical clarity, and extremely sharp single glass transitions in the range of 34–153°C. Thermomechanical testing of these materials confirms their excellent shape memory behavior, high recovery force, and low mechanical hysteresis (especially on multiple cycles), effectively behaving as ideal elastomers above T_g. We believe these materials represent a new and potentially important class of SMPs, and should be especially useful in applications such as biomedical microdevices. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Studies toward the synthesis of the shark repellent pavoninin-5

Sharks are the most dangerous predators of people in the sea, resulting in people being mauled and killed each year. A shark repellent could help to diminish this danger. The aglycone of the shark repellent pavoninin-5, (25R)-cholest-5-en-3β,15α,26-triol (5a), was synthesized from diosgenin (9). Removing mercury from the Clemmensen reduction of 9 gave a higher yield of (25R)-cholest-5-en-3β,16β,26-triol, 10a, and was also more environmentally friendly. Attempted methods for the transposition of the C-16β hydroxyl to the 15α position are described. A successful method for this transposition via the 15α-hydroxy-16-ketone, 8a, using the Barton deoxygenation reaction on the 16-alcohol 14b, is reported.