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Pig liver Esterase (PLE) and Pig Pancreas Lipase (PPL) catalysed hydrolysis of (±) trans-3-carbethoxy and (±) cis-3-acetoxymethyl 4-substituted β-lactams revealed interesting dependence on C-3, C-4 stereochemistry and nature of C-4 substituents.

Palladium mediated regio and stereospecific syntheses of exomethylene benzo-and naphtho dioxans are described.

4-Aryl or heteroaryl 3-methylene β-lactams 2a–2c underwenthighly stereospecific cycloaddition with various nitrones 3a–3c . The method offers an enantiospecific route to 3-hydroxy-β-lactams. © 1997 Published by Elsevier Science Ltd.

Pig-liver esterase, which catalyzed the hydrolysis of substrates containing both saturated and α,β-unsaturated/cyclopropanecarboxylic esters (methyl and ethyl), was studied. An exclusive hydrolysis of the saturated esters was observed. Kinetic experiments revealed that the presence of deactivated carbonyl in the unsaturated/cyclopropanecarboxylic esters and their weaker bindings are both responsible for the observed specificity. The relative binding abilities of the substrates have been explained in light of Jones active-site model. The regioselectivity has been exploited in the synthesis of intermediates for the thromboxane synthetase inhibitor.

The new tetracyclic 9H,10H-indolizino[1,2-b]indole-1-one derivatives (7a-d, 7ea, 7eb) have been synthesized by modified Fischer indole synthesis from the enol ether of 2,5-dihydroxy-7-methyl-6-cyano-indolizine (3) and arylhydrazines (4a-g). Attempted N-methylation of 7a-d produced a series of autoxidized products including 10-hydroperoxy-1-methoxyindolizino[1,2-b]indole (9a-d) as the major product accompanied with methylperoxides (10a-d and 11a-d) and 2-formyl-3-(pyridine-2-yl)indole (12a, 12c) derivatives as the minor products. A plausible mechanism of the autoxidation is postulated based on the isolation of some intermediates. The reaction is thought to proceed through azaenolate/enamine intermediates following a novel type of autoxidation.

The structures of all possible current algebras consistent with the divergence anomalies of currents in {sigma} models in 1+1 and 3+1 dimensions are discussed. The current-algebra models with Wess-Zumino anomalies are shown to be consistent even without a Schwinger term in 1+1 dimensions but in 3+1 dimensions it will stay in the minimal framework.

Inclusion of phaseolinone, a newly described mycotoxin, at 20 micrograms per ml in a solid culture medium (blood agar overlay) and at 50 micrograms per ml in a liquid culture (medium 199) inhibited the growth of L. donovani promastigotes. About 90% of the motile promastigotes lost motility after exposure to 50 micrograms per ml of phaseolinone for 6-7 h and here 3-day-old culture was more sensitive than 7-day-old culture. In an in vitro assay, DNA dependent RNA polymerase activity of 3-day-old promastigotes was considerably inhibited in the presence of this toxin. Therefore, this key enzyme was suggested to be one of the sites of action of phaseolinone.

The Yang-Baxter relation among the monodromy matrices of the SU(2) Wess-Zumino-Witten model is derived using the operator product expansion of currents guided by the conformal invariance of the theory. This is subsequently used to solve for the S -matrix and mass spectra by the algebraic Bethe ansatz. The particle states describe free massless fermions.

It is pointed out how quantum effects can alter the Kac-Moody algebra in the spectrum space for integrable nonlinear systems and cause the emergence of the central extension of the algebra.

Objectives/Hypothesis: Patients having null mutations in the USH2A gene do not produce usherin and therefore are not positive for immunohistochemical staining of the usherin protein. Thus, immunostaining for usherin can serve as a reliable diagnostic tool for Usher syndrome type IIa. Study Design: Prospective. Methods: Immunohistochemical staining for usherin was carried out in basement membrane of minor salivary gland tissue from subjects with confirmed Usher syndrome type IIa and from archival minor salivary gland tissue from patients without Usher syndrome as control samples. Quantitative usherin messenger RNA analysis was performed using minor salivary gland biopsy tissue. Results: Five subjects with Usher syndrome type IIa had no immunostaining in minor salivary gland tissue, whereas control minor salivary gland tissue did stain with usherin antibody. No usherin RNA was detected in biopsy specimens from patients with confirmed Usher syndrome IIa. Conclusion: The feasibility was confirmed of diagnosing Usher syndrome type IIa using purified usherin antibody in subjects having two null USH2A mutations.

People with Usher's syndrome type IIa have mutations in a novel gene encoding a protein with domains commonly found in many types of extracellular matrix and cell surface receptor proteins. Here we report that this protein, which we refer to as usherin, is a new basement membrane protein. In the mouse, usherin has a broad, but not ubiquitous, tissue distribution. Usherin is found in all of the capillary and structural basement membranes of the human and mouse retina and in the murine inner ear at both post-natal day 0 and in the adult. High levels of usherin are also observed in tissues not affected in Usher's syndrome type IIa, including spleen, testis, oviduct, epididymis, submaxillary gland, and large and small intestines. Many organs are completely devoid of usherin, including the brain, skin, kidney, lung, liver, and skeletal muscle. Expression was observed in the smooth muscle of the small intestine, colon, and oviduct, however, usherin is not present in cardiac smooth muscle. Usherin is critical for normal development and tissue homeostasis in the inner ear and retina, illustrating yet another example of the importance of basement membranes in the development and function of tissues.

The quantity of central importance in quantum field theory is just not the action of its classical counterpart but the partition function that contains it and also the path measures. As a consequence even if the action part is trivial, i.e., it is equivalent to a free theory by redefining the phases of the complex fields, the quantum theory may not still be trivial. The path measures may acquire a nontrivial Jacobian because of this redefinition of the variables. Analogous thing was the approach of Fujikawa [1] to study the axial anomaly, except that in those cases only the infinitesimal variation (Ward identities) of the effective actions are calculable. The contention of the present talk is that for the classically trivial theories involving chiral fermions in any even space time dimensions the complete effective actions can be exactly evaluated. The techniques involved are well known [2] but the final results are interesting. Below is a short prescription.

The adenomatous polyposis coli (APC) gene is etiologically associated with familial adenomatous polyposis and gastrointestinal malignancies, but its cellular function and role in tumorigenesis are unclear. Recent reports indicate that wild-type, but not mutant, APC gene product (APC) is associated with and promotes the assembly of cytoskeletal microtubules in vitro, suggesting that this mechanism has importance in tumor development. Because other microtubule-associated proteins (MAPs) undergo phosphorylation in their normal functioning, we postulated that APC is a phosphoprotein. HCT116 cells, containing full-length APC protein, were [32P]-prelabeled, and a 300-kDa band corresponding to phosphorylated APC was immunoprecipitated using each of three different anti-APC antibodies. High voltage electrophoresis of [32P]-labeled APC showed the presence of phospho-serine and phospho-threonine residues. Further immunoprecipitation analyses showed phosphorylation of i) full-length APC in human lymphoblastoid cells and ii) carboxyl-truncated APC in SW480 and DiFi colon carcinoma cells. Thus, APC is probably a phosphoprotein in normal and malignant tissues. We hypothesize a mechanism whereby phosphorylation of APC may play a regulatory role in its interaction with microtubules. This may involve phosphorylation of (Ser/Thr)-Pro amino acid motifs in APC′s basic domain. We propose that deletion of this domain disrupts APC binding to microtubules, explaining how APC mutations are linked to cancer development.

This paper develops a search-theoretic framework for analyzing migration decisions of workers who can only observe the quality of a location by migrating to the location after accepting a job there. After learning the location quality, the worker can stay at the current job, search locally at the same location, or search for a job at another location (leading to repeat migration). This paper develops the properties of optimal search, migration, and repeat migration decisions, and finds how revealed location quality influences the tradeoffs between local search and repeat migration. The effects of search costs and better job opportunities on the reservation levels of wages and revealed quality levels are also determined.

DNA-dependent RNA synthesis in an isolated rat liver nuclei in vitro assay was inhibited by 41 and 61% in the presence of α-amanitin, the inhibitor specific for RNA polymerase II and phaseolinone, a new mycotoxin, respectively. This inhibition reached 97% when these two inhibitors were present together. The RNA polymerase activity present in a nucleolar fraction was inhibited by greater than 80% in presence of phaseolinone, but phaseolinone and DNA showed no interaction as judged from CD spectra or density gradient centrifugation of toxin-treated DNA. This evidence suggested that phaseolinone inhibited RNA polymerase activity other than RNA polymerase II.

The {U(1)} n Schwinger model is shown to have a hidden global SU( n ) invariance where the fermion fields are coupled to n 2 −1 vector fields forming the adjoint multiplet. Of these vector fields only n −1 are the gauge fields while the others are dependent degrees of freedom. This model, which is called SU( n ) torus QCD, is shown, in the Coulomb gauge, to be equivalent to the full SU( n ) QCD 2 in a fixed gauge where A 1 , aa = 0 and A 1, ab = 0 for a ≠ b . All the gauge-invariant consequences of the two models are, therefore, the same. The quarks are topologically confined for any finite n . However, in the strong coupling phase the quarks are liberated in the limit n → ∞.

This paper describes the nature of equilibrium for a dynamic game between a monopolist and an entrant who adopts a learning strategy for cost reduction. The learning process is characterized as a continuous-time Poisson process where each success reduces a part of the entrant's cost difference with the incumbent. The entrant chooses a stream of expenditure after every success to control the instant probability of the next success. The techniques of semi-Markov decision processes are used to characterize equilibrium learning decisions at every stage, distribution of entry times, and the effects of subsidies, technical progress, etc. on pre-entry and post-entry learning strategies.

As licensing contracts usually require the licensee firm to purchase tied inputs from the seller of the technology, the licensee firm has an incentive to embark on an R&D program for development of substitutes for the tied inputs. This paper characterizes the licensee firm's optimal speed of R&D and the optimal expected date of switch-over to the substitute inputs in an infinite-horizon model under uncertainty about the timing of success of the R&D program. The effects of different government subsidies or taxes, changes in input prices and other parameters on the optimal speed of R&D and on the expected date of switchover to the substitute are also investigated. It is also shown that strategic behavior by the seller of the technology may delay the development of the substitute by the licensee firm.

We argue that in the perturbative framework the natural symmetry of the fermionic determinant is the perturbative gauge transformation (p.g.t.) which differs from the usual gauge transformation of the effective action through the absence of terms independent of the coupling constant. Calculated in a non-perturbative framework appropriate for large gauge function, the sum of these latter terms vanish. In three dimensions the invariance of the full fermion determinant under large gauge transformations is thus ensured due to the invariance under p.g.t. of the Chern-Simons term arising in some perturbative regularisations.

The linear problem associated with the Lax operator of the classical sine-Gordon theory can be recast into the monodromy matrix form that can be extended to quantum theory as well. Product of the quantum monodromy matrices will have contributions from the singularities arising out of the operator product expansions of sine-Gordon field. This enables one to find the star-triangle relations. This is a generalization of the method used by Thacker for the non-relativistic nonlinear Schrödinger field theory. In the infinite volume limit, it leads to an unambiguous description of the algebra involving the scattering data operators. Starting from a vacuum the module of physical states are constructed by the application of chains of the scattering operators and they turn out to have definite eigenvalues of energy and momentum. The mass-spectra and two-particle S matrix elements can be calculated straightforwardly and they coincide with the well-known results of Zamolodchikov and Zamolodchikov. It is also shown that the particle states can be created by a generalized Jordon-Wigner transformation of the free fermionic creation operators — thus establishing a link between the S matrix element and certain co-cycles.

Leading singular behavior of the product of scalar fields at short distance is exploited to obtain the Yang-Baxter relation involving the direct product of monodromy matrices of quantum sine-Gordon field theory. No lattice regularisation is necessary and hence the space-time symmetries are manifest. Correctness is checked by comparing the classical limit, mass spectra and S -matrix.

Using the properties of massless free Fermi fields in (1-1) dimensions, it is shown that the spinor inverted form of Klaiber's operator solution to Thirring model is also a scale-invariant solution of the model. But unlike the former it admits a nonvanishing SU(n) current coupling in the generalization of the model to include U(n) symmetry. The value of this coupling constant is fixed and equals Dashen-Frishman number −4π (n + 1) . The general form of the 2m-point function is given and operates product expansions are exhibited in terms of composite local operators. Scale dimensions of all the bilinear and quadrilinear local operators with U(n) symmetry are computed and are found to depend on n. However, different parts of a composite local operator belonging to different irreducible U(n) representations have the same dimension.

An explicit form of a colour-singlet Fermion field is constructed from the operator solution of SU(n) Thirring model where the quark-fields are known to be confined in LSZ sense. In simple cases of massless quarks these ferions are free with zero mass and can be expressed as the antisymmetric composites of constituent quark fields. This simple exercise suggests an alternative to conventional two-dimensional QCD which seems to confine all Fermion including baryons by Schwinger mechanism.

The optimal extraction policy of a known resource stock in an economy which has imperfect information about existence of a new technology is discussed. The optimal program is shown to depend on the remaining stock and the current information about existence of the new technology (which is updated every period). For two special forms of social welfare function, the optimal extraction policy is shown to be more conservative than in the situation of perfect information. The effects of improved information and greater availability of the known stock on the optimal extraction policy are also investigated.

This paper shows that under certain conditions, an economy with securities and post-state spot markets can support rational expectations equilibria of economies in a partial Arrow-Debreu regime of incomplete contingent markets. Using these conditions, examples are constructed to show that non-optimal equilibria might exist for the securities regime and introduction of additional securities might make everyone worse off. These examples are shown to be robust and valid in a more general context than those of Hart ( J. Econ. Theory 11 (1975), 418–443).

Thirring-Wess and Schwinger models generalized to $\mathrm{U}(n)$ symmetry are explicitly solved by using the operator solution to the $\mathrm{U}(n)$ symmetric Thirring model. The gauge-invariant $\mathrm{SU}(n)$ current densities vanish identically, indicating the absence of colored physical states. The fermion screening mechanism occurs entirely due to the masslessness of the Abelian vector-boson field. There is no dynamical generation of mass for the non-Abelian vector bosons, which have to have zero mass for the solvability of the model.

A set of identities involving triple products of free fermion fields belonging to the fundamental representation of U(n) is established. These would give a direct bosonised form of U(n) massless as well as massive Thirring model for $$g_\upsilon = - \frac{{4\pi }}{{n + 1}}$$ . The identities are also shown to exist for fields whose leading operator product expansion is same as that of free fermion fields. This would then give us an exactly solvable bosonised form of U(n) Schwinger model.

A current algebraic approach is taken to realise the two-dimensional chiral model having anomaly analogous to that of Wess and Zumino. The conserved currents are shown to be a combination of bosonic and fermionic ones. The equations of motion of the fermions are realised through its commutation algebra with the Sugawara-like energy-momentum tensor. Quantisation of the anomaly parameter is shown to be a consequence of consistent statistics.

An operator solution is constructed in (1,1) dimensions to the massless quantum chromodynamics of n fermion quarks and n2 − 1 vector boson gluons with local colour SU(n) symmetry. The interacting quark field is a confined SU(n) Thirring field with zero Abelian coupling. The colour gluons are dependent Lie fields obeying the gluon-free fermionic current identity. Explicit local infinitesimal operator colour transformations (with an arbitrary coordinate-independent Lorentz vector coefficient defining the gauge) are given and the requirement of proper colour covariance linked to the vanishing of the coloured quark source currents and hence to the absence of coloured quark-composite states. The status of Noether's theorem is also clarified.