Search results for "clic"

Endothelin receptors mediating contraction in goat cerebral arteries

1993

1. The aim of the present study was to identify the subtype of receptor mediating contraction to endothelin-1 and sarafotoxin S6b in goat isolated middle cerebral arteries. 2. Endothelin-1, endothelin-2 and endothelin-3 contracted cerebral arteries in a concentration-dependent manner. Although the three peptides were full agonists, the order of potency was endothelin-1 = endothelin-2 > endothelin-3, with a relative potency of endothelin-1 and endothelin-2 versus endothelin-3 of approximately 280. Sarafotoxin S6b induced concentration-dependent contractions with lower potency than endothelin-1/endothelin-2, higher potency than endothelin-3 and a higher maximum response than the three endothe…

Progesterone increases basal 3',5'-cyclic adenosine monophosphate formation and down-regulates the agonist-induced inositol phosphates generation in …

1992

Whether the placenta is a target tissue for estrogens and progesterone, and their putative mechanism of action, is still a controversial question in the literature. The effect of progesterone and estradiol on 3′,5′-cyclic adenosine monophosphate (cAMP) and inositol phosphates generation in human term placenta was investigated. Placental explants were incubated in vitro for up to 48 h in the absence and in the presence of estradiol, progesterone or both steroids (0.1 μmol/l final concentration in all cases), and were stimulated with terbutaline, a β-adrenergic agonist, (0.1 mmol/l) or angiotensin II(1 μmol/l), The cAMP content was measured by a competitive protein binding assay, and the gene…

Altered atypical coupling of γ-aminobutyrate type A receptor agonist and convulsant binding sites in subunit-deficient mouse lines

2001

We searched for subunit correlations for GABA(A) receptor-associated atypically GABA-insensitive [35S]TBPS binding. The homomeric beta3 subunit receptors could be excluded, as GABA-insensitive [35S]TBPS binding was present in beta3-/- mice. Localization of GABA-insensitive [35S]TBPS binding correlated best with those of delta, alpha4 and alpha6 subunit mRNAs. The amounts of GABA-insensitive [35S]TBPS binding components were increased in delta-/- mice, but dramatically reduced in alpha6-/- mice, suggesting a role for alpha6 but excluding delta subunits.

Possible role of polycyclic aromatic hydrocarbons in the onset of melanoma: preliminary data.

2019

New Insight to the Chemistry of Polyaza[n]paracyclophanes. A 15N NMR Study

2001

Bis(oxazoline) Lewis Acid Catalyzed Aldol Reactions of PyridineN-Oxide Aldehydes—Synthesis of Optically Active 2-(1-Hydroxyalkyl)pyridine Derivatives…

2006

A new, short, and simplified procedure for the synthesis of optically active pyridine derivatives from pro-chiral pyridine-N-oxides is presented. The catalytic and asymmetric Mukaiyama aldol reaction between ketene silyl acetals and 1-oxypyridine-2-carbaldehyde derivatives catalyzed by chiral copper(II)-bis(oxazoline) complexes gave optically active 2-(hydroxyalkyl)- and 2-(anti-1,2-dihydroxyalkyl)pyridine derivatives in good yields and diastereoselectivities, and in excellent enantioselectivities-up to 99 % enantiomeric excess. As a synthetic application of the developed method, a full account for the asymmetric total synthesis of a nonnatural indolizine alkaloid is provided.

Catalytic Enantioselective Aza-Reformatsky Reaction with Cyclic Imines

2016

A catalytic highly enantioselective aza-Reformatsky reaction with cyclic aldimines and ketimines for the synthesis of chiral b-amino esters with good yields and excellent enantioselectivities is reported.Areadily available diaryl prolinol is used as a chiral ligand, ZnMe2 as a zinc source and ethyl iodoacetate as reagent in the presence of air atmosphere. The reaction with cyclic ketimines generates a quaternary stereocenter with excellent levels of enantioselectivity. Furthermore, five-membered N-sulfonyl ketimines were used as electrophiles with good enantiomeric excesses, under the optimized reaction conditions. Moreover, several chemical transformations were performed with the chiral b-…

Products of groups and group classes

1994

Letχ be a Schunck class, and let the finite groupG=AB=BC=AC be the product of two nilpotent subgroupsA andB andχ-subgroupC. If for every common prime divisorp of the orders ofA andB the cyclic group of orderp is anχ-group, thenG is anχ-group. This generalizes earlier results of O. Kegel and F. Peterson. Some related results for groups of the formG=AB=AK=BK, whereK is a nilpotent normal subgroup ofG andA andB areχ-groups for some saturated formationχ, are also proved.

Quantum Groups, Star Products and Cyclic Cohomology

1993

After some historical remarks, we start with a rapid overview of the star-product theory (deformation of algebras of functions on phase space) and its applications to deformation-quantization. We then concentrate on Poisson-Lie groups and their “quantization”, give a star-product realization of quantum groups and discuss uniqueness and the rigidity as bialgebra of a universal model for the quantum SL(2) groups. In the last part we develop the notion of closed star-product (for which a trace can be defined on the algebra), show that it is classified by cyclic cohomology, permits to define a character and that there always exists one; finally we show that the pseudodifferential calculus on a …

Electronic excitations of 1,4-disilyl-substituted 1,4-disilabicycloalkanes: a MS-CASPT2 study of the influence of cage size.

2007

We present a multistate complete active space second-order perturbation theory computational study aimed to predict the low-lying electronic excitations of four compounds that can be viewed as two disilane units connected through alkane bridges in a bicyclic cage. The analysis has focused on 1,4-disilyl-1,4-disilabicyclo[2.2.1]heptane (1a), 1,4-bis(trimethylsilyl)-1,4-disilabicyclo[2.2.1]heptane (1b), 1,4-disilyl-1,4-disilabicyclo[2.1.1]hexane (2a), and 1,4-bis(trimethylsilyl)-1,4-disilabicyclo[2.1.1]hexane (2b). The aim has been to find out the nature of the lowest excitations with significant oscillator strengths and to investigate how the cage size affects the excitation energies and the…