Results 71 to 80 of about 18,407 (265)

Synthesis of Organic and Inorganic Compounds in Asymptotic Giant Branch Stars

Galaxies
After the synthesis of carbon in the core of asymptotic giant branch (AGB) stars, carbon is dredged up to the surface by convection. Many carbon-based molecules are formed in the subsequently developed stellar wind.
Sun Kwok
doaj   +1 more source

The Brightest Carbon Stars

, 1997
It is currently accepted that Hot-Bottom-Burning (HBB) in intermediate-mass asymptotic giant branch (AGB) stars prevents the formation of C~stars. Nevertheless, we present in this paper the results of some detailed evolutionary calculations which show that even with HBB we obtain C~stars at the highest luminosities reached on the AGB.
Frost, Cheryl, Cannon, Robert, Lattanzio, John, Wood, Peter, Forestini, Manuel   +4 more
openaire   +2 more sources

The R Stars: Carbon Stars of a Different Kind [PDF]

Publications of the Astronomical Society of the Pacific, 1997
After 16 years of radial-velocity observations of a sample of 22 R-type carbon stars, no evidence for binary motion has been detected in any of them. This is surprising considering that approximately 20% of normal late-type giants are spectroscopic binaries, and the fraction is close to 100% in barium, CH, and subgiant/dwarf CH and barium stars.
openaire   +2 more sources

Directed evolution of enzymes at the crossroads of tradition and innovation

FEBS Open Bio, EarlyView.
An iterative cycle of data‐driven enzyme optimization comprising four stages: genetic diversification of a template enzyme, expression of protein variants, high‐throughput evaluation, and machine‐learning‐guided redesign of the next variant library.
Maria Tomkova, Andrej Mirossay, Erik Sedlak   +2 more
wiley   +1 more source

The Chemical Composition of Carbon Stars. II. The J‐Type Stars

The Astrophysical Journal, 2000
Abundances of Li, heavy elements and carbon isotope ratios have been measured in 12 J-type galactic carbon stars. The abundance analysis shows that in these stars the abundances of s-process elements with respect to the metallicity are nearly normal.
Abia, Carlos, Isern, Jordi
openaire   +2 more sources

Dose‐dependent hepatotoxicity of hydrogen peroxide in HepG2 cells and its modulation by CYP450 induction

FEBS Open Bio, EarlyView.
NMR metabolomics revealed concentration‐dependent metabolic perturbations in HepG2 cells exposed to H2O2. Rifampicin pretreatment enhanced metabolic competence, attenuated toxin‐induced alterations and produced metabolite profiles more consistent with human liver physiology, supporting the use of CYP450‐induced HepG2 models for improved in vitro ...
Maren Jinks, Garth L. Maker, Emily C. Davies, Berin A. Boughton, Samantha Lodge   +4 more
wiley   +1 more source

Abundance of Heavy r-process Elements in CEMP-rs Stars: The Role of the i-process

The Astrophysical Journal
Carbon-enhanced metal-poor (CEMP) stars are ancient stars enriched in carbon and heavy elements. Some of these stars exhibit enhanced s -process and/or r -process elements, and hence are classified as CEMP-s, CEMP-rs, or CEMP-r.
A. M. Riyas, D. Karinkuzhi, S. Van Eck, A. Choplin, S. Goriely, L. Siess, M. V. Keerthy, A. Jorissen, T. Merle   +8 more
doaj   +1 more source

Abundances in J-Type Carbon Stars [PDF]

International Astronomical Union Colloquium, 1988
It has been found by Utsumi(1985a,b) that in J-type carbon stars of C4-5 and WZ Cas(C9,2J Li), abundances of s-process elements with respect to Fe are nearly normal, while in normal carbon stars of C5-8, heavy metals are overabundant by factors of 10-100, and rare-earth elements are overabundant by a factor of about 10.In the MK system, most J-type ...
openaire   +1 more source

Identifying and characterising a plant GH1 β‐glucosidase that exhibits hydrolytic activity on N‐linked glucopyranoside

FEBS Open Bio, EarlyView.
We report the first β‐glucosidase with demonstrated hydrolytic activity on an N‐linked glycopyranoside. The enzyme, native to maize, was biochemically characterised for this novel reaction, and structural modelling of the enzyme–substrate complex revealed several clues to the underlying reduced catalytic rate relative to its native O‐glycopyranoside ...
Hani Gharabli, Carlotta Chiesa, Maher Abou Hachem, Ditte Hededam Welner   +3 more
wiley   +1 more source

A homogeneous view of asymptotic giant branch carbon stars as seen by Gaia

Astronomy & Astrophysics
Context. Carbon stars on the asymptotic giant branch are major contributors to the dust enrichment of galaxies, with gas mass-loss rate values up to Ṁ ≈ 10−4 M⊙ yr−1. They represent the final evolutionary stage of low- and intermediate-mass stars, during
Liberatori A., Hatzidimitriou D., Antoniadis K., Pastorelli G., Trabucchi M., Groenewegen M. A. T., Bossini D., Girardi L., Marigo P., Bressan A., Kallimanis I. N., Costa G., Katsis V., Vasilopoulos G., Chatzipetros S.   +14 more
doaj   +1 more source