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- Bjärngard, Bengt E, et al.
(author)
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Tissue-phantom ratios from percentage depth doses
- 1996
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In: Medical Physics. - : Wiley. - 0094-2405. ; 23:5, s. 629-634
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Journal article (peer-reviewed)abstract
- When converting fractional (percentage) depth doses to tissue-phantom ratios, one must use a factor that accounts for the different source-to-point distances. Two minor correction factors are also involved. One is the ratio of total to primary dose at the two different distances from the source, for the same depth and field size. This factor is usually ignored. It was determined experimentally that this can introduce up to 1.5% error at 6 MV. The second correction factor reflects differences related to scattered photons and electrons at the depth of normalization in the two geometries. This correction is accounted for in published conversion procedures. It was found to be less than 1% provided the normalization depth is sufficient for electron equilibrium, which occurs first well beyond the depth of maximum dose. One may avoid electron-equilibrium problems by using an interim normalization depth that provides electron equilibrium with some margin, renormalizing to a shallower depth if desired. With this precaution, the accuracy when measured fractional depth doses were converted to tissue-phantom ratios was comparable to that of directly measured tissue-phantom ratios even when the correction factors were ignored.
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| 5. |
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| 6. |
- Luo, X, et al.
(author)
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Transparent ion-conducting ceria-zirconia films made by sol-gel technology
- 1998
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In: SOLAR ENERGY MATERIALS AND SOLAR CELLS. - : ELSEVIER SCIENCE BV. - 0927-0248. ; 53:3-4, s. 341-347
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Journal article (peer-reviewed)abstract
- Films of Ce-Zr oxide were made by sol-gel deposition according to three different routes. Cyclic voltammetry showed that Li+ intercalation/deintercalation took place if the Ce content was sufficient. The films had a high transmittance for visible ligh
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| 8. |
- Zhu, JW, et al.
(author)
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Olefinic acetates, Delta-9, 11-14:OAc and Delta-7,9-12:OAc used as sex pheromone components in three geometrid moths, Idaea aversata, I-straminata, and I-biselata (Geometridae, Lepidoptera)
- 1996
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In: JOURNAL OF CHEMICAL ECOLOGY. - : PLENUM PUBL CORP. - 0098-0331. ; 22:8, s. 1505-1526
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Journal article (other academic/artistic)abstract
- Pheromone compounds so far identified from most geometrid moths consist of all-Z diene, triene, or tetraene hydrocarbons with chain lengths of C-17 to C-21, and their monoepoxide derivatives biosynthesized from linoleic and linolenic acids. The present st
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| 9. |
- Zhu, J. W., et al.
(author)
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Reductase specificity and the ratio regulation of E/Z isomers in pheromone biosynthesis of the European corn borer, Ostrinia nubilalis (Lepidoptera Pyralidae)
- 1996
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In: Insect Biochemistry and Molecular Biology. - : Elsevier BV. - 0965-1748. ; 26:2, s. 171-176
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Journal article (peer-reviewed)abstract
- Species specificity of moth sex pheromones is in many cases achieved by means of specific blends rather than by specific components. Two pheromone strains of the European corn borer, Ostrinia nubilalis, use (E)- and (Z)-11-tetradecenyl acetate in different ratios as their pheromone, but show the same ratio of the pheromone precursors (70:30 E/Z-11-tetradecenoic acid). The hypothesis that the ratio of the pheromone components in the two strains and their hybrids is controlled by the specificity of the reductase system, responsible for conversion of acid to the corresponding alcohol precursors, was tested. Deuterium-labeled alcohols, aldehydes and fatty acids corresponding to the two pheromone components were topically applied to the pheromone glands in different ratios and their selective incorporation into pheromone components was determined by gas chromatography with mass selective detection. Acetylation of the (E)- and (Z)-11-tetradecenols was unselective, whereas the corresponding aldehydes and acids were selectively incorporated into the pheromone components. Z strain females selectively metabolized the Z-isomers whereas E strain females converted the E-isomers. The E strain being the most selective of the two strains. Hybrids converted both geometric isomers. The relative conversion rate of both E- and Z-isomers of all tetradecenoic acids with the double bond in positions from 7-12, was also determined. In addition to the Δ11-isomers, the E strain females converted (E)-8-tetradecenoic acid into acetate and the Z strain females converted (E)-12-tetradecenoic acid. None of these substrates occur naturally in the pheromone gland, but (E)-12-tetradecenyl acetate is a pheromone component of the Asian corn borer O. furnacalis. Thus the possibility for conversion of (E)-12-tetradecenoic acid to acetate in the Z strain, as well as the earlier reported conversion of (Z)-11-tetradecenoic acid to acetate in O. furnacalis, suggests that O. furnacalis is closest related to the Z strain of O. nubilalis.
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| 10. |
- Zhu, J. W., et al.
(author)
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Reidentification of the female sex pheromone of the Indian meal moth, Plodia interpunctella : evidence for a four-component pheromone blend
- 1999
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In: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703 .- 1570-7458. ; 92:2, s. 137-146
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Journal article (peer-reviewed)abstract
- Pheromone gland extracts from calling female Plodia interpunctella contained at least seven compounds that consistently elicited electroantennographic responses from male antennae upon gas chromatographic analysis. Three of these compounds were found to be the previously identified gland constituents, i.e., (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:OAc), (Z,E)-9,12-tetradecadienal (Z9,E12-14:Ald) and (Z,E)-9,12-tetradecadienol (Z9,E12-14:OH). A fourth EAD-active compound was identified as (Z)-9-tetradecenyl acetate (Z9-14:OAc). The homologue (Z)-11-hexadecenyl acetate (Z11-16:OAc) was also identified in the extracts, but showed no EAD activity. The identity of all five compounds was confirmed by comparison of GC retention times and mass spectra with those of synthetic standards. In flight tunnel tests there were no significant differences in response of male P. interpunctella to the bait containing all four EAD-active compounds and the responses to female gland extacts. A behavioural assay of different two-compound blends in the flight tunnel showed that only addition of the corresponding aldehyde to the major pheromone component Z9,E12-14:OAc raised the male response. A subtractive assay, however, revealed that the exclusion of any of the compounds from the complete four-compound blend reduced its activity significantly. We thus conclude that the female-produced sex pheromone of P. interpunctella consists of at least four components, i.e., Z9,E12-14:OAc, Z9,E12-14:Ald, Z9,E12-14:OH and Z9-14:OAc. In a field trapping test performed in a storage facility, the four-component blend attracted significantly more males of P. interpunctella than traps baited with Z9,E12-14:OAc alone. In contrast, the highest number of Ephestia kuehniella males was found in the traps baited with this major component, suggesting that the secondary pheromone components contribute to the species specificity of the blend.
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