Ginsparg-Wilson relation and the overlap formula

The fermionic determinant of a lattice Dirac operator that obeys the Ginsparg-Wilson relation factorizes into two factors that are complex conjugate of each other. Each factor is naturally associated with a single chiral fermion and can be realized as a overlap of two many body vacua.Comment: 4 pages, plain tex, no figure

The overlap lattice Dirac operator and dynamical fermions

I show how to avoid a two level nested conjugate gradient procedure in the context of Hybrid Monte Carlo with the overlap fermionic action. The resulting procedure is quite similar to Hybrid Monte Carlo with domain wall fermions, but is more flexible and therefore has some potential worth exploring.Comment: Further expanded version. 12 pages, plain Te

Isolation and characterization of an insertion element-like repetitive sequence specific for Mycobacterium tuberculosis complex

We report the characterization of an insertion-like repetitive sequence containing the clone of Mycobacterium tuberculosis. This repetitive sequence contains seven inverted repeats. Restriction fragment length polymorphism studies using this probe have shown that it is not a highly polymorphic probe but rather shows conservative fingerprint pattern. Out of the 150 strains tested, only three showed different fingerprint patterns. It has several direct and inverted repeats. Homology studies of the putative protein coding region show that this repeat element might code for a metalloproteinase of M. tuberculosis. Homology studies also implicate this repeat element to be from a very essential region of the M. tuberculosis genome participating in recombination. This repeat has been found to be an ideal target for polymerase chain reaction to detect M. tuberculosis

On the continuum limit of fermionic topological charge in lattice gauge theory

It is proved that the fermionic topological charge of SU(N) lattice gauge fields on the 4-torus, given in terms of a spectral flow of the Hermitian Wilson--Dirac operator, or equivalently, as the index of the Overlap Dirac operator, reduces to the continuum topological charge in the classical continuum limit when the parameter $m_0$ is in the physical region $0<m_0<2$.Comment: latex, 18 pages. v2: Several comments added. To appear in J.Math.Phy

Differential expression of a unique protein by intracellular Mycobacterium tuberculosis complex

We have investigated the changes in the protein synthesis pattern in guinea pig peritoneal macrophages following infection with virulent Mycobacterium tuberculosis H37Rv in vitro. By 35S methionine labelling of the newly synthesized proteins followed by ultracentrifugation, SDS-PAGE (sodium dodecyl sulphate polyacrylamide gel electrophoresis) and autoradiography, the protein synthesis pattern of the control uninfected macrophages and the infected macrophages in vitro were compared. By adding cycloheximide to the macrophage cultures, the protein synthesis of macrophages was inhibited and the protein synthesis pattern of M. tuberculosis has been analysed. We have identified a mycobacterial protein of molecular weight 17 kDa which was expressed exclusively in the cytosolic fraction of M. tuberculosis- infected guinea pig macrophages in vitro

Utility of polymerase chain reaction using two probes for rapid diagnosis of tubercular pleuritis in comparison to conventional methods

We have used polymerase chain reaction (PCR) with IS6110 and a new set of primers from an insertion element like repetitive sequence, (TRC4) to detect Mycobacterium tuberculosis in pleural effusion samples from 50 patients having pleuritis. The results of PCR were compared with the results of conventional methods like smear, culture and adenosine deaminase activity. Thirty six specimens were positive and 14 were negative by PCR. Among the 36 samples, 33 were from patients with clinical evidence of tuberculosis including response to anti-tuberculosis therapy. Only six samples were positive by the gold standard which is culture, and three were positive by smear. The measurement of adenosine deaminase activity classified 19 samples as positives. The overall sensitivity and specificity of PCR was 100 and 85 per cent respectively. PCR using IS6110 and TRC4 primers is a sensitive test as compared to conventional tests for detection of M. tuberculosis from pleural fluid samples of patients with tubercular pleuritis

The fate of Mycobacterium tuberculosis in activated human macrophages

Human peripheral blood monocytes, that are unstimulated in vitro, permit free multiplication of intracellular Mycobacterium tuberculosis after 72 h in culture. There was no killing of bacilli in the intracellular environment even after in vitro activation of monocytes with a cocktail of lipopolysaccharide, phorbol myristate acetate, interferon gamma and tumour necrosis factor-alpha. We also tested the ability of adenosine triphosphate (ATP) in reducing the intracellular viability of mycobacteria. Infected monocytes upon ATP treatment underwent cell death, but no loss in the intracellular viability of M. tuberculosis or M. smegmatis could be observed

Bounds on the Wilson Dirac Operator

New exact upper and lower bounds are derived on the spectrum of the square of the hermitian Wilson Dirac operator. It is hoped that the derivations and the results will be of help in the search for ways to reduce the cost of simulations using the overlap Dirac operator. The bounds also apply to the Wilson Dirac operator in odd dimensions and are therefore relevant to domain wall fermions as well.Comment: 16 pages, TeX, 3 eps figures, small corrections and improvement

Ginsparg-Wilson Fermions: A study in the Schwinger Model

Qualitative features of Ginsparg-Wilson fermions, as formulated by Neuberger, coupled to two dimensional U(1) gauge theory are studied. The role of the Wilson mass parameter in changing the number of massless flavors in the theory and its connection with the index of the Dirac operator is studied. Although the index of the Dirac operator is not related to the geometric definition of the topological charge for strong couplings, the two start to agree as soon as one goes to moderately weak couplings. This produces the desired singularity in the quenched chiral condensate which appears to be very difficult to reproduce with staggered fermions. The fermion determinant removes the singularity and reproduces the known chiral condensate and the meson mass within understandable errors.Comment: Corrected a few typos and changed some references. Minor changes to the conten

Development of DNA probes for M. tuberculosis

Attempts were made to develop DNA probes for M. tuberculosis. Random library of M. tuberculosis was constructed in plasmid pGEM -4. Selection of recombinant clones was made by hybridisation with 32P labelled M. tuberculosis probe. Ten recombinant clones were selected on the basis of strong signals from the random library. These 10 clones named pTRC1-10 were subjected to tests for specificity and sensitivity. On this basis, pTRC4 was chosen and this is also, useful in restriction fragment length polymorphism (RFLP) studies