Results 241 to 250 of about 41,864 (294)

Allosterically Activated Diels−Alder Catalysis by a Ribozyme

Journal of the American Chemical Society, 2005
We describe the allosteric control of Diels-Alder reactions by a small organic effector, theophylline. This is achieved by converting a Diels-Alder ribozyme into an allosterically regulated system. In contrast to other published systems, we have a bond-forming reaction with two small-molecule substrates and multiple turnover.
Helm, M., Petermeier, M., Ge, B. X., Fiammengo, R., Jaschke, A.   +4 more
openaire   +2 more sources

Factors Influencing Eastern Kingsnake Diel Activity

Copeia, 2012
We used radio-telemetry to identify diel activity patterns in the Eastern Kingsnake, Lampropeltis getula getula in Southwestern Georgia. We monitored tagged snakes at four time periods within a 24-hour cycle (0800–1359 h, 1400–1959 h, 2000–0159 h, and 0200–0759 h) in spring, summer, and fall (March–November), which comprise the annual activity period ...
Jennifer M. Howze, Lora L. Smith
openaire   +1 more source

Antibacterial and antishigellosis activity of Xylopia staudtii (engl. & diels), Annonaceae

Journal of Ethnopharmacology, 2021
Xylopia staudtii is a medicinal plant which fruits are traditionally used in western Cameroon as a spice in the preparation of soups known for their abdominal cramp relieving properties. Often identified as Xylopia africana, its bark is used in the treatment of dysentery in Mont Cameroun localities. This plant could therefore contain active ingredients
Nguiam, Michel Pouofo, Wouamba, Steven Collins Njonte, Longo, Frida, Kamkumo, Raceline Gounoue, Kenne Foweda, Larissa Donji, Dzeufiet, Paul Desire Djomeni, Ndjakou, Bruno Lenta, Sewald, Norbert, Boyom, Fabrice Fekam, Kouam, Simeon Fogue, Dimo, Theophile   +10 more
openaire   +3 more sources

Diel activity periodicities in meadow arthropods

Canadian Journal of Zoology, 1972
The Williams pitfall trap was used near Belleville, Ontario, to separate catches of 30 taxa of meadow arthropods into six periods daily for 199 days. Most taxa were diurnal, only six being definitely nocturnal. This produced an overall lack of symmetry in the activity of the arthropod community. Activity peaks for predatory taxa and for those of their
C. D. Dondale, J. H. Redner, R. B. Semple   +2 more
openaire   +1 more source

Aminocatalytic Asymmetric Diels–Alder Reactions via HOMO Activation

Accounts of Chemical Research, 2012
In the first successful catalytic asymmetric Diels-Alder reaction in 1979, Koga and colleagues used a chiral aluminum complex as a Lewis acid catalyst, but since then, researchers have developed numerous catalytic systems for these reactions. By 2000, several chiral organic compounds, such as the salts of imidazolidinones or TADDOLs, emerged as robust ...
Jun-Long, Li, Tian-Yu, Liu, Ying-Chun, Chen   +2 more
openaire   +2 more sources

Diel Activity in the Yellow Bullhead

The Progressive Fish-Culturist, 1977
Abstract Twelve adult yellow bullheads (Ictalurus natalis) were tested individually in an electronic shuttlebox device (Ichthyotron) to determine their diel activity pattern. Activity, monitored by photocells, was quantified as the bullheads shuttled between the chambers of the device.
W. W. Reynolds, M. E. Casterlin
openaire   +1 more source

Robust analysis of diel activity patterns

Journal of Animal Ecology
AbstractResearch Highlight: Iannarilli, F., Gerber, B. D., Erb, J., & Fieberg, J. R. (2024). A ‘how‐to’ guide for estimating animal diel activity using hierarchical models. Journal of Animal Ecology, https://doi.org/10.1111/1365‐2656.14213. Diel activity patterns are ubiquitous in living organisms and have received considerable research attention ...
Neil A. Gilbert, Davide M. Dominoni
openaire   +2 more sources

Thermally activated multiple self‐healing diels‐alder epoxy system

Polymer Engineering & Science, 2017
The introduction of thermo‐reversible covalent bonds in the molecular network is a recent approach to prepare self‐healing polymers upon a suitable thermal trigger. Among reversible reactions, Diels–Alder (D‐A) cycloaddition is an ideal candidate for the synthesis of mendable polymers, such as epoxy resins, with improved operative life. The D‐A adduct,
Dello Iacono S, Martone A, Pastore A, Filippone G, Acierno D, Zarrelli M, Giordano M, Amendola E   +7 more
openaire   +4 more sources

New theophylline-activated Diels–Alderase ribozymes by molecular engineering

Org. Biomol. Chem., 2009
Allosteric ribozymes were developed by rational design and step-wise optimization. These ribozymes accelerate a Diels-Alder reaction between anthracene and maleimide derivatives. The optimized sequence is efficiently activated by theophylline under single and multiple turnover conditions and distinguishes between structurally similar effector molecules.
Markus, Petermeier, Andres, Jäschke
openaire   +2 more sources

Antiplasmodial and antitrypanosomal activity of Triclisia sacleuxii (Pierre) Diels

Phytomedicine, 2008
The antiplasmodial and antitrypanosomal activities of Triclisia sacleuxii (Pierre) Diels were investigated on three Plasmodium falciparum strains [FcB1, 3D7 (chloroquine-sensitive) and W2 (chloroquine-resistant) strains] and on Trypanosoma brucei Tbsf 221.
Murebwayire, Sangabo, Frederich, Michel, Hannaert, V., Jonville, Marie, Duez, Pierre   +4 more
openaire   +2 more sources