Search Results - (Author, Cooperation:C. M. Adams)

2013-09-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Cryoelectron Microscopy ; DNA, Fungal/chemistry/genetics ; *Gene Expression Regulation, Fungal ; Multiprotein Complexes/*chemistry ; Nucleic Acid Conformation ; Protein Conformation ; RNA Polymerase II/*chemistry ; Saccharomyces cerevisiae/*enzymology/genetics ; Saccharomyces cerevisiae Proteins/*chemistry ; Transcription Factors, General/*chemistry ; *Transcription Initiation, Genetic

1570-7458

Springer Online Journal Archives 1860-2000

Biology

Résumé Dix substances provoquant l'inappétence, appartenant à sept classes chimiques différentes, ont été examinées isolément et en diverses combinaisons quant à leur effet sur Locusta migratoria. L'inappétence obtenue avec différentes combinaisons a indiqué que les effects des substances chimiques individuelles s'additionnaient. Un groupe de quatorze composés phénoliques dérivés des feuilles de sorgho a été éprouvé à des concentrations existant dans la nature. Bien que ces composés n'aient pas causé individuellement une inappétence mesurable, le mélange de tous les composés, aux mêmes concentrations, a réduit considérablement l'ingestion d'aliments.

Abstract Combinations of feeding deterrents are additive in their effects on the feeding behaviour of Locusta migratoria. The effect has been shown within and across different chemical classes. A mixture of fourteen different phenolic compounds from Sorghum bicolor tested in naturally occurring concentrations is deterrent although the individual levels of deterrence are not measurable. The significance of the findings in relation to plant resistance is discussed.

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The effect of process variables in controlled co-deposition of copper-nickel films employing one oscillated electron beam and two pure sources was systematically studied. Structural features were investigated by optical microscopy and X-ray and electron beam analysis. Correlations between structure and growth conditions were sought. The effect of substrate temperature was found to be similar to that observed in single element deposition: Grain size increased with temperature and preferred orientation appeared above 300° C. At high frequencies of electron beam oscillation a homogeneous binary vapour appears to be formed and deposited similarly to a single component vapour. Films co-deposited at low frequencies exhibited topographies suggesting periodic rather than simultaneous deposition of two vapours. Controlled and reproducible co-deposition was confined to experimental limits due to the use of equal area sources. It is believed that the difference in thermal properties of the source materials leading to the above limitation, can be compensated for by evaporation from sources of different surface areas.

Electronic Resource

1573-2932

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Abstract The abilities of foliage of selected agricultural crop and native boreal forest species to neutralize acidic raindrops were compared. The species differed widely in their responses. Neutralization was influenced to a large extent by leaf wettability and was poorly related with species' susceptibility to foliar injury from acid rain sprayings. Little neutralization of pH 3.0 droplets occurred on very waxy leaves, e.g. cabbage (Brassica oleracea L.), due to the small contact area between the leaf surface and raindrops. In contrast, on sunflower (Helianthus annuus L.) and radish (Raphanus sativus L.) leaves, which are pubescent and easily wettable, neutralization was considerable. For all agricultural crop species examined, the pH of droplets drying on cotyledons was consistently higher than on the leaves. The pH values of raindrops were also higher when the foliage was injured by the acid rain, probably due to leakage of cellular contents. Among boreal forest species examined, bunchberry (Cornus canadensis L.) was particularly good at neutralizing natural acid rain, increasing the pH from 3.9 to 6.6 after 9 hr of foliar contact, while the response of other boreal species ranged from a final pH of 4.8 to 5.7 under the same conditions. Simulated raindrops on wild sarsaparilla (Aralia nudicaulis L.) were never neutralized but increased in acidity as they evaporated. Chemical analyses of droplets collected from foliage showed calcium (Ca) and potassium (K) to he the major cations entering the neutralized droplets. Neutralization of acidic raindrops appears to occur through two processes: solubilization of alkaline dusts and exudates on the leaf surface, and ion exchange removal of H+ by the foliage.

Electronic Resource

0749-1581

Chemistry ; Analytical Chemistry and Spectroscopy

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

The fully proton-coupled 15N NMR spectra of pyrimidine with natural isotope abundance and of bis-labelled [1,3-15N2]pyrimidine, obtained using single pulse experiments, are described. The 15N and 1H spectra are analysed for 2J, 3J and 4J(NH) as well as N,N and H,H coupling constants.

3 Ill.

Electronic Resource