We report the discovery, using NICMOS on the Hubble Space Telescope, of an arcsecond-diameter Einstein ring in the gravitational lens system B1938+666. The lensing galaxy is also detected, and is most likely an early-type. Modelling of the ring is presented and compared with the radio structure from MERLIN maps. We show that the Einstein ring is consistent with the gravitational lensing of an e...

In the title compound, C(21)H(21)N(3)OS·C(3)H(7)NO, the carbonitrile mol-ecule is built up of two fused six-membered rings and one six-membered ring linked through a spiro C atom. The 1,3-diaza ring adopts an envelope conformation and the cyclo-hexane ring adopts a chair conformation. The dihedral angle between the aromatic rings is 46.7 (3)°. In the crystal, the components are linked by N-H⋯O ...

In the title compound, C(22)H(14)O(2)S(3), the dioxane ring is disordered over two sites [site occupancies = 0.623 (3) and 0.377 (3)]; both components adopt half-chair conformations. The two benzothio-phene ring systems are asymmetrically twisted away from the attached thio-phene ring [dihedral angles = 20.57 (3) and 6.70 (3)°] and are oriented at an angle of 26.83 (3)°. No significant hydrogen...

In the title compound, C(13)H(12)N(4)S, an amino N atom is connected to a 1,3-benzothia-zole fused-ring system and a dimethyl-substituted pyrimidine ring, these components being aligned [inter-planar dihedral angle = 1.9 (1)°]. The secondary amino N atom forms an inter-molecular N-H⋯N hydrogen bond to an N atom of the fused ring of an adjacent mol-ecule, generating a centrosymmetric cyclic hydr...

In the title compound, C22H21N3O2, the pyrimidine ring is essentially planar [maximum deviation = 0.018 (2) Å] and forms dihedral angles of 22.70 (8) and 0.97 (7)°, respectively, with the fused benzene ring and the hy-droxy-substituted benzene ring. The piperidine ring has a chair conformation and the pyran ring has a flattened twist-boat conformation. The hy-droxy group was refined as disorder...

The main aim of this paper is to provide a description of parameter test ideals of local Cohen-Macaulay rings of prime characteristic p. The nature of this description will be such that it will allow us to give an algorithm for producing these ideals. The results in this paper will follow from an analysis of Frobenous maps on injective hulls of the residue fields of the rings under consideratio...

In the title mol-ecule, C(9)H(6)BrN(3)OS(2), the dihedral angle between the benzene ring and the five-membered ring is 5.5 (3)°. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, N-H⋯S hydrogen bonds link mol-ecules into centrosymmetric dimers creating R(2) (2)(8) ring motifs. In addition, there are inter-molecular S⋯S [3.430 (2) Å] contacts. The crystal used was ...

The fission yeast Schizosaccharomyces pombe provides a genetic model system for the study of cytokinesis. As in many eukaryotes, cell division in the fission yeast requires an actin-myosin-based contractile ring. Numerous components of the contractile ring that function in ring assembly, positioning and contraction have been characterized. Many of these proteins are evolutionarily conserved, su...

E!ectively random "ring occurs frequently in the brain. Random components of neuronal drive are therefore often major in#uences on activity. We describe here how level of drive, inhibitory/excitatory balance, correlation between input streams, EPSP/IPSP characteristics, the nature of the postsynaptic neuron all a!ect pattern and level of "ring, the in#uence often interacting in complex ways. Ra...