Luminescence properties of nanosized zinc oxide (ZnO) colloids greatly depend on their surface properties. These surface properties in turn are largely determined by the method of preparation. The procedure for producing ZnO colloids consists of two major steps: (1) preparing the precursor by reacting zinc acetate with ethanol and (2) hydrolyzing the precursor to form the colloid by using lithium hydroxide. The sample colloids in this study were prepared by hydrolyzing zinc acetate precursors containing various concentrations of Zn 2+ with different concentrations of lithium hydroxide. The luminescence properties were evaluated by the energy difference, ∆E, between the band gap and the emission energy which were obtained from the onset of the absorption spectrum and the peak wavelength of the emission spectrum, respectively. The surface properties of ZnO particles were studied using thermal gravimetric and infrared techniques. ZnO particles produced via these procedures are not pure but have acetate (CH 3 COO -) groups on their surface. These groups originate from the reagent, zinc acetate. These acetate groups consist of a mixture of unidentate, chelate, and bridging type structures. The amount and structure of the acetate groups depend on the concentrations of Zn 2+ in the precursors and the amount of lithium hydroxide used to hydrolyze these precursors. The luminescence properties, ∆E, also changed with the concentrations of Zn 2+ and lithium hydroxide. Our results, however, could be normalized to the concentration ratio of zinc acetate to lithium hydroxide, ZnAc/ LiOH. The amount of acetate groups on the ZnO particles prepared at the same concentration ratio of ZnAc/ LiOH were the same, and the IR spectra were also coincident with each other. Furthermore, the visible luminescence properties, ∆E, are also the same, for the ZnO colloids prepared at the same concentration ratio of ZnAc/LiOH, and increased with increasing ratios. These results suggest that the visible luminescence properties of ZnO particles depend on their surface properties which are in turn determined by the concentration ratio of ZnAc/LiOH.

All algorithms of the OCT system were useful for discriminating glaucoma. Among these, GCC measurements offered the best parameters for the clinical diagnosis of glaucoma in patients with high myopia and concomitant perimetric glaucoma.

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The degree of metamorphopsia significantly correlated with the tangential retinal displacement. Dislocated Müller cells may stimulate the photoreceptors located away from original positions, which consequently results in the sensation of metamorphopsia in patients with an epiretinal membrane.

Extranuclear DNA has not been considered a normal cellular constituent either by cytologists or by geneticists, although exceptional instances have been recognized, such as the cytoplasmic DNA of the amphibian o6cyte.1 Nonetheless, suggestive evidence has been reported of DNA in chloroplasts,2' 6, I in mitochondria,3 and in the kinetoplasts.4The present study was prompted by two considerations, one genetical and the other biochemical. We have recently isolated a series of nonchromosomal mutants in the green alga Chlamydomonas, which indicate the presence of an extensive nonchromosomal genetic system.' Many of these strains cannot grow photosynthetically, suggesting that mutations have occurred in nonchromosomal genes which affect chloroplast traits. Where are these nonchromosomal genes located and are they composed of DNA? A recent report that Chlamydomonas contains extranuclear Feulgen-positive particles,6 and that DNA isolated from Chlamydomonas contains a satellite band with a buoyant density lighter than that of the major component,7 led us to examine the nucleic acid content of chloroplasts isolated from Chlamydomonas.In this paper we describe a procedure for isolating relatively intact chloroplasts free of other cellular debris. DNA extracted from these isolated chloroplasts has been characterized with respect to buoyant density and base composition.Materials and Methods.-(1) Isolation of chloroplasts: Cells (Chlamydomonas reinhardi, strain 21 gr) were grown with a six-hr doubling time in 10-liter batches in minimal medium with 5% CO2,8 harvested from the logarithmic phase, washed, and resuspended in W medium.9 W medium contains 0.25 Al sucrose, 2.5% Ficoll (Pharmacia), 5% dextran-40 (Pharmacia), 0.006 M mercaptoethanol, 0.01% bovine serum albumin, 1 X 10-3 M MgCl2, 1 X 10-2 M MnCl2, and 1.5 X 10-3 M CaCl2 in 10-2 M tris-HCl buffer at pH 7.8. Cells were broken in a cold French pressure cell at 3,000 psi. All subsequent steps in the isolation procedure were carried out at 2°. Five ml of the broken cell mixture was layered onto a discontinuous gradient containing 5 ml each of 2.5 M, 2.0 Mf, 1.5 M, and 1.0 Al sucrose in W medium. The gradients were centrifuged in the Spinco Model L at 25,000 rpm in the SW 25.1 rotor for 90 min.After centrifugation five green bands were present, as shown in Figure 1. Examination in the light microscope revealed that bands 1 and 2 contained broken chloroplasts, band 3 contained largely intact chloroplasts, bands 4 and 5 contained chloroplasts and some unbroken cells. The bands were recovered by piercing the bottom of the tube and collecting drops. Only band 3 was retained for further purification, diluted with W medium not containing sucrose, and banded again in a sucrose density gradient as above. After centrifugation, band 3 was again collected

DIMBOA[2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one] is a benzoxazinoid (Bx), part of the chemical defense system of graminaceous plants such as maize, wheat, and rye. When Bombyx mori larvae were fed artificial diets containing DIMBOA, they died in three days. In contrast, Mythimna separata larvae, a serious pest of rice, maize, sorghum, wheat etc., grew well on the same diets. Three kinds of glucosides [1-(2-hydroxy-4-methoxyphenylamino)-1-deoxy--glucopyranoside-1,2-carbamate (methoxy glucoside carbamate), 2-O--glucopyranosyl-4-hydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA-2-O-Glc), and 2-O--glucopyranosyl-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (HMBOA-2-O-Glc)] were identified by LC-MS and NMR analyses from the frass of M. separata that had been fed on a DIMBOA-containing diet. Furthermore, the incubation of DIMBOA with a midgut tissue suspension of M. separata in the presence of UDP-D-glucose generated DIMBOA-2-O-Glc. These findings strongly suggest that glucosylation by UDP-glucosyltransferase(s) was important for detoxification to circumvent the defenses of host plants against M. separata larvae.