Field theory of the interacting string: The closed string

We recast dual models in the language of a quantum field theory of functional fields, restricting ourselves for simplicity to the closed string model. We derive the dynamics for both scalar and spinor functional fields from a unique parametrization invariant action. Passages to the Hamiltonian formalism and second quantization are explicitly worked out for the closed mesonic string in the front form. The results are equivalent to those obtained earlier by GGRT, i.e. no ghost fields at the price of an anomalous number of space-time dimensions and a tachyon. Finally, we use the parametrization invariance requirement on the action to derive couplings of closed strings to local fields by extending a global U(1) invariance built in the free action into a local one in the functional sense. We construct the self-couplings of closed string fields by requiring these to be consistent with the gauge invariance of the external fields. This procedure uniquely leads (for the open string) to the string splitting picture of Nambu and Mandelstam. The closed string is found to cross itself and then split up into two others. Both open and closed strings have quartic interactions corresponding to strand (for the open string) and lobe (for the closed string) exchanges. The case of the interacting fermionic model is not treated here.     

Reaction of 2,2-bis(trifluoromethyl)-1,1-dicyanoethylene with 6,6-dimethylfulvene: cycloadditions and a rearrangement

Reaction of 2,2-bis(trifluoromethyl)-1,1-dicyanoethylene (BTF; 1) with 6,6-dimethylfulvene (2) affords the expected Diels-Alder cycloadduct, 7-(1-methylethylidene)-3,3-bis(trifluoromethyl)bicyclo[2.2.1]hept-5-ene-2,2-dicarbonitrile (3), in good yield. The cycloadduct 3 is unstable and exists in equilibrium with the starting materials in less polar solvents. In more polar environment, the [4 + 2] adduct 3 either reverts to starting materials, or, in a competing process, is converted to the formal [2 + 2] adduct, 2-(1-methylethylidene)-7,7-bis(trifluoromethyl)bicyclo[3.2.0]hept-3-ene-6,6-dicarbonitrile (6). In the presence of acid, 3 is converted to a third isomeric form, 1,3a,5,6-tetrahydro-7-methyl-5,5-bis(trifluoromethyl)-4H-indene-4,4-dicarbonitrile (8). Both 6 and 8 are formed with complete regiospecificity. Quantum mechanical calculations and X-ray crystallographic studies of this ensemble of reactions by BTF, and the analogous set of reactions by its progenitor, tetracyanoethylene (TCNE), reveal several interesting facets. The conversion of 3 to 6 occurs in certain polar solvents, in the presence of silica gel and alumina, as well as in the solid state. Single crystals of 3 were observed by X-ray crystallography to undergo crystal-to-crystal rearrangement to 6. The conversion of 3 to 8 proceeds by the initial retro-Diels-Alder reaction followed by isomerization of the fulvene to 1-isopropenyl-1,3-cyclopentadiene that then reacts with BTF to give the alternative Diels-Alder product as a single regioisomer. A hybrid density functional theory (DFT) method at the B3LYP/6-31G(d) level of theory gave calculated relative energies of 0.0, -9.0, and -18.8 kcal/mol for 3, 6, and 8, respectively. The same method was also used to correctly predict the regiochemical outcome of the cycloaddition of BTF with 1-isopropenyl-1,3-cyclopentadiene. Finally, an explanation is offered for the preference of the persubstituted cyanoolefins BTF and TCNE to add to the exocyclic diene portion of 1-isopropenyl-1,3-cyclopentadiene and the contrasting preference of 2-acetyloxy-2-propenenitrile to add to the endocyclic diene.     

Synthesis of enantioenriched propargylic alcohols related to polyketide natural products. A comparison of methodologies

[reaction: see text] Applications of methodology for the synthesis of propargylic alcohols related to polyketide natural products were examined. Noyori's asymmetric transfer hydrogenation of alpha-chiral alkynones was found to be highly selective and catalyst controlled. Additions of TMS acetylene to alpha-chiral aldehydes, catalyzed by a Ti(O-i-Pr)(4)-BINOL complex, were diastereoselective but substrate dependent.     

Evaluation and optimisation of a splitter injector for capillary chromatography

Summary The repeatability and discrimination of a home-made splitter injector, operated under various conditions, towards a C-6 to C-24 test sample were investigated. Other different test samples were analysed to prove the integrity of the injector. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Surface states of metastable (GaAs)1−xGe2x alloys

The proposed order-disorder transition as x varies in metastable (GaAs)_1?xGe_2x alloys should be observable in photoemission experiments. There should be large “kinks” in the (100) surface state energies as functions of x near the critical composition x_c.     

Cell surface receptors for endogenous mouse type C viral glycoproteins and epidermal growth factor: tissue distribution in vivo and possible participation in specific cell-cell interaction

We have described previously the detection and tissue distribution of free cell surface receptors for ecotropic R-MuLV envelope glycoprotein and the growth factor EGF in vivo [1]. More recently, we have reported the chromosomal map position of the ecotropic viral receptor and its conservation between subspecies of the genus Mus [2]. This work has shown, for the first time, the presence of multiple, independently segregating cell surface receptor genes specific for different classes of ecotropic type C viral envelope glycoprotein. In this report we extend these findings and identify chromosome 2 as coding for the receptor used by M813, an ecotropic MuLV from a feral Asian mouse. This new receptor is probably also used by oncogenic, recombinant (MCF class) MuLV of C3H origin.     

Some preliminary acoustical considerations in the design for the proposed Wellington (New Zealand) town hall

The preliminary design for Wellington Town Hall, New Zealand, is an evolution from the successful design for Christchurch Town Hall. It includes, however, the results of a decade of experimental work on the effects of early lateral reflections on listener preference for orchestral music. The basic form of the auditorium remains an arena, roughly elliptical in plan, and containing within its boundaries large suspended surfaces to ensure appropriate reflection sequences. The acoustical design objectives include the combination of a long reverberation time, “envelopment” due to the lateral reflections and clarity as encourtered in Christchurch Town Hall. Advances in the provision of diffusion and understanding of the acoustical requirements for ensemble are included in the proposals. The experimental work and other advances in knowledge relating to concert hall design are reviewed, and their application in the design of Wellington Town Hall is discussed.