519 research outputs found
Detection of Circulating Filarial Antigen
Affinity binding to specific solid phase antibody, immune complex binding to Raji
cells or PEG precipitation of immune complexes was used in conjunction with Western
blotting to detect circulating filarial antigen in filarial sera. A high molecular weight
antigen was present in free as well as complex form. PEG precipitation method
revealed specific filarial antigens in the low molecular weight region also
Increased serum levels of anti-filarial (IgA) antibodies in patients with tropical pulmonary eosinophilia
Tropical Pulmonary Eosinophilia (TPE) is diagnosed on the basis of high peripheral
eosinophilia associated with clinical symptoms and signs. Elevated levels of total and antifilarial
immunoglobulins is one of the characteristic features of TPE. Ten clinically diagnosed
TPE patients and ten controls were compared for their anti-filarial and anti-ascaris antibody
levels of classes IgG, IgM and IgA. While, IgG antibodies exhibited considerable cross reactivity
between Ascaris and Filarial antigens, IgM antibodies showed nonspecific binding to filarial
antigens. However, IgA antibodies were found to discriminate between TPE and control sera
better than IgG and IgM antibodies
The Spatial Averaging Limit of Covariant Macroscopic Gravity - Scalar Corrections to the Cosmological Equations
It is known that any explicit averaging scheme of the type essential for
describing the large scale behaviour of the Universe, must necessarily yield
corrections to the Einstein equations applied in the Cosmological setting. The
question of whether or not the resulting corrections to the Einstein equations
are significant, is still a subject of debate, partly due to possible
ambiguities in the averaging schemes available. In particular, it has been
argued in the literature that the effects of averaging could be gauge
artifacts. We apply the formalism of Zalaletdinov's Macroscopic Gravity (MG)
which is a fully covariant and nonperturbative averaging scheme, in an attempt
to construct gauge independent corrections to the standard
Friedmann-Lemaitre-Robertson-Walker (FLRW) equations. We find that whereas one
cannot escape the problem of dependence on \emph{one} gauge choice -- which is
inherent in the assumption of large scale homogeneity and isotropy -- it is
however possible to construct \emph{spacetime scalar} corrections to the
standard FLRW equations. This partially addresses the criticism concerning the
corrections being gauge artifacts. For a particular initial choice of gauge
which simplifies the formalism, we explicitly construct these scalars in terms
of the underlying inhomogeneous geometry, and incidentally demonstrate that the
formal structure of the corrections with this gauge choice is identical to that
of analogous corrections derived by Buchert in the context of spatial averaging
of scalars.Comment: 18 pages, no figures, revtex4; v2 - minor clarifications added; v3 -
minor changes in presentation to improve clarity, reference added, to appear
in Phys. Rev.
Fate of the false monopoles: induced vacuum decay
We study a gauge theory model where there is an intermediate symmetry
breaking to a meta- stable vacuum that breaks a simple gauge group to a U (1)
factor. Such models admit the existence of meta-stable magnetic monopoles,
which we dub false monopoles. We prove the existence of these monopoles in the
thin wall approximation. We determine the instantons for the collective
coordinate that corresponds to the radius of the monopole wall and we calculate
the semi-classical tunneling rate for the decay of these monopoles. The
monopole decay consequently triggers the decay of the false vacuum. As the
monopole mass is increased, we find an enhanced rate of decay of the false
vacuum relative to the celebrated homogeneous tunneling rate due to Coleman
[1].Comment: 10 pages, 4 figure
Production & characterization of monoclonal antibodies to Mycobacterium tuberculosis
Background & objectives: Monoclonal antibodies (MAbs) against Mycobacterium tuberculosis H37Rv culture
filtrate (CF) were raised by immunizing BALB/c mice and characterization was done. Attempts have been
directed towards identifying mycobacterial antigens in biological fluids by employing polyclonal and monoclonal
antibodies specific for M. tuberculosis. Immunohistologic studies, using MAbs for the localization of whole or
fragmented bacilli in the biopsy specimens were also carried out.
Methods: Intrasplenic IS and intraperitoneal IP routes of immunization, were compared. The MAbs were
characterized for their isotype, binding specificity, nature of binding epitope, reactivity in immunoassays etc.
Results: IS and IF’ routes of immunization, were compared and IP was found superior. Ten MAbs designated
TRC l-10 were produced. Of these, 7 MAbs, TRC 1-7 reacted with the 30/31 kDa doublet (antigen 85 complex),
TRC 8 with 12 kDa in addition to 30/31 kDa and TRC 9 and 10 with the 24 and 12 kDa antigens respectively.
Six MAbs were classified as broadly cross reactive and 2 showed limited cross reactivity. TRC 8 and 10 showed
species specificity. Employing TRC 8 in sandwich ELISA, antigen was detected in sera from 17 of 25 pulmonary
tuberculosis patients and 3 of 20 controls. TRC 8 was found to be useful in detecting antigens specifically in
M. tuberculosis and M. leprae infected tissues, by immunoperoxidase staining.
Interpretation & conclusion: TRC 8 was found to be restricted in its reactivity to M. tuberculosis complex and
M, leprae. TRC 8 may prove useful in immuno-diagnosis of tuberculosis
Anti-filarial IgG antibodies in patients with Bancroftian filariasis and tropical pulmonary eosinophilia
Anti-filarial (anti- B. malayi adult as well as anti- B. malayi microfilarial) IgG antibody levels were measured by enzyme
linked immunosorbent assay (ELISA) in asymptomatic microfilaria carriers, acute, chronic and tropical pulmonary
eosinophilia (TPE) patients, endemic and non-endemic controls. Controls from endemic areas had higher antibody titres
compared with controls from non-endemic areas. The antibody response in different groups of filariasis patients was not stage
specific. There were no association between clinical disease and antibody levels except in TPE. Though TPE patients had very
high antibody levels, a proportion of them had low levels suggesting heterogeneity in TPE population
Modeling and simulation for the spread of Covid-19 in an Indian city: a case study
We present a case study on modeling and predicting the course of Covid-19 in the Indian city of Pune. The results presented in this paper are concerned primarily with the wave of infections triggered by the Delta variant during the period between February and June 2021. Our work demonstrates the necessity for bringing together compartmental stock-and-flow and agent-based models and the limitations of each approach when used individually. Some of the work presented here was carried out in the process of advising the local city administration and reflects the challenges associated with employing these models in a real-world environment with its uncertainties and time pressures. Our experience, described in the paper, also highlights the risks associated with forecasting the course of an epidemic with evolving variants
Backreaction of Cosmological Perturbations in Covariant Macroscopic Gravity
The problem of corrections to Einstein's equations arising from averaging of
inhomogeneities ("backreaction") in the cosmological context, has gained
considerable attention recently. We present results of analysing cosmological
perturbation theory in the framework of Zalaletdinov's fully covariant
Macroscopic Gravity. We show that this framework can be adapted to the setting
of cosmological perturbations in a manner which is free from gauge related
ambiguities. We derive expressions for the backreaction which can be readily
applied in \emph{any} situation (not necessarily restricted to the linear
perturbations considered here) where the \emph{metric} can be brought to the
perturbed FLRW form. In particular these expressions can be employed in toy
models studying nonlinear structure formation, and possibly also in N-body
simulations. Additionally, we present results of example calculations which
show that the backreaction remains negligible well into the matter dominated
era.Comment: 17 pages, 5 figures, revtex4; v2 -- typos fixed, 1 reference updated,
to appear in Phys Rev
Identification of circulating parasite antigen in patients with bancroftian filariasis
Because many cases of lymphatic filariasis cannot be diagnosed either clinically or by
immunodiagnostic test based on antibody detection, recent efforts have been more
directed towards developing methods for detecting parasite antigen in the blood or urine.
Using a solid phase (Sepharose 4B) two-site immunoradiometric assay (IRMA)
employing hyperimmune rabbit antifilarial antisera, we have previously shown (Hamilton
et al., 1984) that essentially all cases ofpatent (ie. microfilaremic) infection in patients with
bancroftian filariasis can be detected by this semi-quantitative assay as well as some
individuals with amicrofilaremic (i.e., 'cryptic') infection. The present communication
reports the results of studies that identify a prominent circulating antigen detected by this
IRMA in sera from patients with microfilaremia. The antigen was eluted from Sepharosebound
rabbit polyclonal antiserum that had been reacted with known antigen positive
sera. It was run in SDS-PAGE, blotted to nitrocellulose paper and identified autoradiographically
using '25l-labelled rabbit antifilarial antiserum. Its high molecular weight
(- 200 kD), stability to acid and boiling, and sensitivity to pronase and periodate suggest
its being a glycoprotein. Isolation of this antigen will permit the development of specific
reagents (such as monoclonal antibodies) which should enhance both the sensitivity and
utility of the currently available antigen detection systems
Excursion Sets and Non-Gaussian Void Statistics
Primordial non-Gaussianity (NG) affects the large scale structure (LSS) of
the universe by leaving an imprint on the distribution of matter at late times.
Much attention has been focused on using the distribution of collapsed objects
(i.e. dark matter halos and the galaxies and galaxy clusters that reside in
them) to probe primordial NG. An equally interesting and complementary probe
however is the abundance of extended underdense regions or voids in the LSS.
The calculation of the abundance of voids using the excursion set formalism in
the presence of primordial NG is subject to the same technical issues as the
one for halos, which were discussed e.g. in arXiv:1005.1203. However, unlike
the excursion set problem for halos which involved random walks in the presence
of one barrier , the void excursion set problem involves two barriers
and . This leads to a new complication introduced by what
is called the "void-in-cloud" effect discussed in the literature, which is
unique to the case of voids. We explore a path integral approach which allows
us to carefully account for all these issues, leading to a rigorous derivation
of the effects of primordial NG on void abundances. The void-in-cloud issue in
particular makes the calculation conceptually rather different from the one for
halos. However, we show that its final effect can be described by a simple yet
accurate approximation. Our final void abundance function is valid on larger
scales than the expressions of other authors, while being broadly in agreement
with those expressions on smaller scales.Comment: 28 pages (18+appendices), 7 figures; v2 -- minor changes in sec 3.2,
version published in PR
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