- Ovipositional responses of Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) to natural products from leaves of two maize (Zea mays L.) cultivars
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Ovipositional responses of Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) to hexane extracts of leaves of two maize (Zea mays L.) cultivars, one resistant (Kisan) and one susceptible (Basilocal), were studied in two-choice bioassays. Gravid females laid a significantly higher percentage of eggs on substrates smeared with extract of Basilocal leaves (HEBL) (69%) than on those smeared with extracts of Kisan leaves (HEKL) (31%). Several chemicals were isolated from HEKL, three of which were characterized as dotriacontanol, heptadecanol, and nonadecanol. These chemicals were either absent or were present in very small amounts in HEBL, but in HEKL they were detected in much larger amounts. Each isolated chemical was tested for its effect on C. partellus oviposition in two-choice bioassays. Maximum ovipositional deterrence (90%) was observed for the compound MR-22a, followed in decreasing order by nonadecanol, MR-7, and heptadecanol. The identity of the remaining compounds is being investigated. The results indicate that the relative resistance of Kisan maize compared to Basilocal is partly due to the presence of certain ovipositional deterrents in its leaves.
- Varshney, Anupam K.,Babu, B. Ravindra,Singh, Ashok K.,Agarwal, Hari C.,Jain, Subhash C.
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- The synthesis of a single enantiomer of a major α-mycolic acid of M. tuberculosis
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We report a synthesis of a single enantiomer of a mycolic acid from Mycobacterium tuberculosis containing a di-cis-cyclopropane. The method can be simply varied to modify the chain lengths or the absolute stereochemistry of either cyclopropane.
- Al Dulayymi, Juma'a R.,Baird, Mark S.,Roberts, Evan
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p. 11939 - 11951
(2007/10/03)
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- Semivolatile and volatile compounds in combustion of polyethylene
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The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
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p. 615 - 627
(2007/10/03)
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- Hair growth composition containing citric acid esters
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Triesters of citric acid are used for inducing, maintaining or increasing hair growth. Compositions for topical application to mammalian hair or scalp comprise an effective amount of from 1% to 99% by weight of an ester of citric acid having the structure (1): where, R1, R2 and R3 each independently represent a branched or unbranched alkyl, alkenyl, aryl, alkylaryl or arylalkyl group, each said group having from 1 to 18 carbon atoms, R4 represents -H, or a branched or unbranched saturated or unsaturated acyl, alkyl, aryl, alkylaryl or aylalkyl group having from 1 to 18 carbon atoms, in the presence of a cosmetically acceptable vehicle for the citric acid ester and in the absence of solid absorbent for the ester;, said effective amount of said ester being sufficient to increase hair growth in the rat, when said composition is applied topically thereto over a period of no more than three months, by at least 10% more than that obtainable using a control composition from which the said ester has been omitted, in accordance with the Rat Hair Growth Test.
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- Syntheses of All Four Stereoisomers Which Are Conformationally Constrained 1,4-Dioxanyl Analogs of the Antineoplastic Ether Lipid ET-18-OCH3
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The syntheses of each of the four nearly optically pure stereoisomers of oxy>phosphocholine (2,3,2',3') were performed by two parallel divergent sequences.Phosphocholines 2 and 3 were prepared via the corresponding 5-heptadecyl-2-(hydroxymethyl)-1,4-dioxanes 21 and 23, respectively, from the completely regiospecific mixed-hydride reductions of (1R,4S,5S)-4-heptadecyl-3,6,8-trioxabicyclooctane (19) and (1R,4R,5S)-4-heptadecyl-3,6,8-trioxabicyclooctane (20), respectively.The two 4-heptadecyl-3,6,8-trioxabicyclooctanes 19 and 20 were the two separable products from an intramolecular cyclization reaction.By a parallel divergent sequence from the enantiomeric starting material, 3-O-benzyl-sn-glycerol (16'), the other two diastereomeric oxy>phosphocholines 2' and 3' were prepared.These four monocyclic oxy>phosphocholines (2,3,2',3') are conformationally constrained analogs of the antineoplastic and immunomodulatory ether lipid rac-2-O-methyl-1-O-octadecylglycero-3-phosphocholine (rac-1) (rac-ET-18-OCH3, rac-Edelfosine).
- Duclos, Richard I.,Makriyannis, Alexandros
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p. 6156 - 6163
(2007/10/02)
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- Melting Behaviour of Fatty Alcohols and Their Binary Blends
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The m.p. of pure fatty alcohols from undecyl to nonadecyl are determined along with those of their corresponding pure fatty acids and their methyl esters ; alternation in m.ps. does not occur in fatty alcohol series unlike the other two.Eutectic formation does not take place in the binary blends of fatty alcohols, but a maximum depression of the m.p. of the lower homologue occurs in presence of 11.0 +/- 1.0 mole percent of higher one in the blend.
- Gaikwad, B. R.,Subrahmanyam, V. V. R.
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p. 513 - 515
(2007/10/02)
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