The aromatic character of some small planar metallic clusters was revisited with an emphasis on their electrons
In contrast to previous reports, our approach based on magnetic ring current as an indicator for aromaticity points out that the σ electron delocalization in molecules behaves as an important contributor to their thermodynamic stability. Ring Applications of 6-butyl-n-hydroxynaphthimide trifluoromethanesulfonic acid in Cross-Coupling Reactions were constructed using electron densities obtained from density functional theory calculations with the B3LYP functional and the 6-311G(d) basis set. Diatropic currents were further confirmed by an analysis of the symmetry of electronic excitations involved. The triatomic B3+ cycle is found to maintain a double σ and π aromaticity when it forms the [B3(NN)3]+ and [B3(CO)3]+ complexes. The planar pentacoordinated mixed copper clusters Cu3Si3+ and Cu3Ge3+ are found to be σ aromatic compounds. The copper hydrides CunHn can better be regarded as nonaromatic rather than aromatic compounds.
The ring current indicator reveals the σ aromatic feature the importance of σ electrons in determining the bonding characteristics of metallic clusters, and they should equally be considered as a key element.Quantification of the (anti)aromaticity of fulvalenes subjected to pi-electron Fulvalenes 3-12 were theoretically studied at the ab initio level of theory. For the global minima structures, the occupation of the bonding (pi)C=C orbital of the interring C=C double bond obtained by NBO analysis quantitatively proves pi-electron cross-delocalization resulting in, at least partially, 2- or 6pi-electron aromaticity and 8pi-electron antiaromaticity for appropriate moieties. The cross-conjugation was quantified by the corresponding occupation numbers and lengths of the interring C=C double bonds, while the aromaticity or antiaromaticity due to cross-delocalization of the pi-electrons was visualized and quantified by through-space NMR shielding surfaces.Kinetic modeling of anaerobic degradation of plant-derived aromatic mixtures by of Wisconsin-Madison, Madison, WI, 53726, USA.Rhodopseudomonas palustris is a model microorganism for studying the anaerobic metabolism of aromatic compounds. While it is well documented which aromatics can serve as sole organic carbon sources, co-metabolism of other aromatics is poorly understood.
This study used kinetic modeling to analyze the simultaneous degradation of aromatic compounds present in corn stover hydrolysates and model the co-metabolism of aromatics not known to support growth of R. palustris as sole organic substrates. The simulation predicted that p-coumaroyl amide and feruloyl amide were hydrolyzed to p-coumaric acid and ferulic acid, respectively, and further transformed via p-coumaroyl-CoA and feruloyl-CoA. The modeling also suggested that metabolism of p-hydroxyphenyl aromatics was slowed by substrate inhibition, whereas the transformation of guaiacyl aromatics was inhibited by their p-hydroxyphenyl counterparts. It also predicted that substrate channeling may occur during degradation of p-coumaroyl-CoA and feruloyl-CoA, resulting in no detectable accumulation of p-hydroxybenzaldehyde and vanillin, during the transformation of these CoA ligated compounds to p-hydroxybenzoic acid and vanillic acid, respectively. While the simulation correctly represented the known transformation of p-hydroxybenzoic acid via the benzoyl-CoA pathway, it also suggested co-metabolism of vanillic acid and syringic acid, which are known not to serve as photoheterotrophic growth Steroid production by isolated theca and granulosa cells after initiation of Hypophysectomized PMSG-primed hamsters were injected with PMSG antiserum and the theca and granulosa cells of the resulting atretic follicles were incubated in vitro. In the absence of added hormone, 17 alpha-hydroxyprogesterone and oestradiol production was not detectable in granulosa cells collected and incubated at 0, 12 and 24 h after antiserum.
Progesterone production was not detected in control incubations at 0 h but was measurable with cells collected at 12 h after PMSG antiserum. When incubated with androstenedione or pregnenolone (10 ng/ml for each) 17 alpha-hydroxyprogesterone and progesterone production by granulosa cells were significantly increased at 0, 12 and 24 h after antiserum. Granulosa cells were capable of aromatizing androstenedione to oestradiol at all times examined. At 0 and 12 h after antiserum to PMSG, isolated thecal shells produced androstenedione. LH stimulation caused increased androstenedione production in all thecae at 0 h, in 50% of the thecae at 12 h and in none at 24 h after antiserum. Thecal shells produced 17 alpha-hydroxyprogesterone in response to LH at 0, 12 and 24 h after antiserum, and produced progesterone at all times examined. Thecae also responded to LH with increased progesterone production up to 72 h after antiserum.
These experiments demonstrate that one important steroidogenic event in atresia may be the loss of activity of C 17,20 lyase in the theca leading to loss of substrate (androstenedione) for granulosa cell aromatization, although aromatase activity is present until at least 24 h after the induction of atresia.Complement dependent amplification of the innate response to a cognate microbial The long pentraxin PTX3 is a fluid-phase pattern recognition receptor, which plays a nonredundant role in resistance against selected pathogens.
