Hydride transfer versus hydrogen radical transfer in thymidylate synthase

The nature of a H-transfer in the thymidylate synthase catalyzed reaction was investigated by comparison of the wild-type enzyme with the W80M mutant. The nature of the H-transfer was not affected, as indicated by intrinsic isotope effects and their temperature dependence. These findings support a single-step hydride transfer instead of a two-step radical transfer.     

Synthesis and oxidation of ‘non-annulated’ vitamin E-like compounds

Two model compounds (3 and 4) having the typical α-tocopherol-type substitution pattern of the aromatic ring, but lacking the annulated pyran ring, have been synthesized. Upon oxidation, the two possible ortho-quinone methides (oQMs) of each are formed in equal ratio. DFT calculations suggest that there is no angular strain in 3 and 4, and each of the oQM pairs is of similar energy. These results prove that the commonly observed regioselectivity in oxidations of vitamin E-type model compounds is not an electronic substitution effect, but a consequence of annulation.     

Syntomic regulators andp-adic integration II:K 2 of curves

We show that the ad hoc regulator of Coleman and de Shalit for elements ofK ₂ of curves evaluated on a holomorphic differential is the same as the syntomic regulator of the same elements cup produced with the same differential. Combined with the results of Coleman and de Shalit this gives a relation between syntomic regulators and special values ofp-adicL-functions. The main technical innovation is the notion of a local index — a kind of generalized residue.     

The naturality in Kirwan's decomposition

Let X be a compact symplectic manifold, K a compact group acting symplectically on X, and assume there is a moment map. In [3], Kirwan defined a stratification on X, and showed that the associated spectral sequence degenerates. In this note, we ask whether this degeneration comes from a stable splitting of X into Thom spaces on the strata. One can also ask a related arithmetic question. Is it true that the splitting Kirwan discovered respects the action of Galois groups? Received: 20 March 1997     

Modal analysis of Bragg onion resonators

From analysis of the high Q modes in a Bragg onion resonator with an omnidirectional reflector cladding, we establish a close analogy between such a resonator and a spherical hollow cavity in perfect metal. We demonstrate that onion resonators are ideal for applications that require a large spontaneous-emission factor beta, such as thresholdless lasers and single-photon devices.     

Dynamic analysis of the semiconductor laser as a current-controlled oscillator in the optical phased-lock loop: applications

A methodology for treating the semiconductor laser as a current-controlled oscillator in an optical phase-lock loop is presented. The formalism is applied to phase demodulation of optical beams, reduction of phase noise by self-homodyning, and phase locking of a semiconductor laser array.     

K-Theory for Triangulated Categories 3 1/2 (A): A Detailed Proof of the Theorem of Homological Functors Dedicated to Daniel Quillen and to the Memory of Robert Thomason

Let A and B be Abelian categories. Let H: A B be a bounded -functor. We prove that H induces a natural map in higher K-theory. From a more precise analysis of the proof, we deduce that it is possible to define a K-theory of the bounded derived category of A, which contains Quillen's K-theory of A as a retract.