63 research outputs found
Towards Protecting Critical National Assets and Preparedness for Response to Hazardous Chemical, Biological and Radiological Attacks
Hazardous chemical, biological and radiological (CBR) materials are catching attention of unscrupulous actors for creating terror and havoc. Threat perception for use of such materials by terrorists and non-state actors for malicious purposes, is not imaginative but real and imminent in today’s context. World has witnessed a number of such incidences in the recent years, e.g., Mustard gas attack against Kurdish forces in Iraq; ricin laced letters sent to US President and others senators; use of Nerve gas agents in Syria; capturing of Uranium from University of al- Mousal, Iraq by IS, etc. National assets like critical buildings where main legislative, historical building, Hospitals are some of the likely targets for CBR attacks attract quick coverage by media. Authorities related with managing and safeguarding mechanisms of the facilities to prevent such events happening also to enhance their capabilities as well as effective response. Essential CBR security should include measures to rapidly detect and effectively deter the CBR incidences their deleterious consequences. In this review, protection of the critical facilities from CBR attacks and capacity in terms of infrastructure, specialised training and mutual aid have been discussed
Spin-ladders with spin gaps: A description of a class of cuprates
We investigate the magnetic properties of the Cu-O planes in stoichiometric
SrCuO (n=3,5,7,...) which consist of CuO double chains
periodically intergrown within the CuO planes. The double chains break up
the two-dimensional antiferromagnetic planes into Heisenberg spin ladders with
rungs and legs and described by
the usual antiferromagnetic coupling J inside each ladder and a weak and
frustrated interladder coupling J. The resulting lattice is a new
two-dimensional trellis lattice. We first examine the spin excitation spectra
of isolated quasi one dimensional Heisenberg ladders which exhibit a gapless
spectra when is even and is odd ( corresponding to n=5,9,...) and a
gapped spectra when is odd and is even (corresponding to
n=3,7,...). We use the bond operator representation of quantum
spins in a mean field treatment with self-energy corrections and obtain a spin
gap of for the simplest single rung ladder (n=3), in
agreement with numerical estimates.Comment: 21 pages, 5 figures upon request, REVTEX, ETH-TH/93-3
Perturbation Theory for Spin Ladders Using Angular-Momentum Coupled Bases
We compute bulk properties of Heisenberg spin-1/2 ladders using
Rayleigh-Schr\"odinger perturbation theory in the rung and plaquette bases. We
formulate a method to extract high-order perturbative coefficients in the bulk
limit from solutions for relatively small finite clusters. For example, a
perturbative calculation for an isotropic ladder yields an
eleventh-order estimate of the ground-state energy per site that is within
0.02% of the density-matrix-renormalization-group (DMRG) value. Moreover, the
method also enables a reliable estimate of the radius of convergence of the
perturbative expansion. We find that for the rung basis the radius of
convergence is , with defining the ratio between
the coupling along the chain relative to the coupling across the chain. In
contrast, for the plaquette basis we estimate a radius of convergence of
. Thus, we conclude that the plaquette basis offers the
only currently available perturbative approach which can provide a reliable
treatment of the physically interesting case of isotropic spin
ladders. We illustrate our methods by computing perturbative coefficients for
the ground-state energy per site, the gap, and the one-magnon dispersion
relation.Comment: 22 pages. 9 figure
Mean-Field Theory for Spin Ladders Using Angular-Momentum Coupled Bases
We study properties of two-leg Heisenberg spin ladders in a mean-field
approximation using a variety of angular-momentum coupled bases. The mean-field
theory proposed by Gopalan, Rice, and Sigrist, which uses a rung basis, assumes
that the mean-field ground state consists of a condensate of spin-singlets
along the rungs of the ladder. We generalize this approach to larger
angular-momentum coupled bases which incorporate---by their mere definition---a
substantial fraction of the important short-range structure of these materials.
In these bases the mean-field ground-state remains a condensate of spin
singlet---but now with each involving a larger fraction of the spins in the
ladder. As expected, the ``purity'' of the ground-state, as judged by the
condensate fraction, increases with the size of the elementary block defining
the basis. Moreover, the coupling to quasiparticle excitations becomes weaker
as the size of the elementary block increases. Thus, the weak-coupling limit of
the theory becomes an accurate representation of the underlying mean-field
dynamics. We illustrate the method by computing static and dynamic properties
of two-leg ladders in the various angular-momentum coupled bases.Comment: 28 pages with 8 figure
Density Matrix Renormalization Group Study of the Spin 1/2 Heisenberg Ladder with Antiferromagnetic Legs and Ferromagnetic Rungs
The ground state and low lying excitation of the spin 1/2 Heisenberg ladder
with antiferromagnetic leg () and ferromagnetic rung () interaction is studied by means of the density matrix renormalization
group method. It is found that the state remains in the Haldane phase even for
small suggesting the continuous transition to the gapless
phase at . The critical behavior for small is studied by
the finite size scaling analysis. The result is consistent with the recent
field theoretical prediction.Comment: 11 pages, revtex, figures upon reques
Paradoxical tuberculosis immune reconstitution inflammatory syndrome (TB-IRIS) in HIV patients with culture confirmed pulmonary tuberculosis in India and the potential role of IL-6 in prediction
Background: The incidence, manifestations, outcome and clinical predictors of paradoxical TB-IRIS in patients with HIV and culture confirmed pulmonary tuberculosis (PTB) in India have not been studied prospectively. Methods: HIV+ patients with culture confirmed PTB started on anti-tuberculosis therapy (ATT) were followed prospectively after anti-retroviral therapy (ART) initiation. Established criteria for IRIS diagnosis were used including decline in plasma HIV RNA at IRIS event. Pre-ART plasma levels of interleukin (IL)-6 and C-reactive protein (CRP) were measured. Univariate and multivariate logistic regression models were used to evaluate associations between baseline variables and IRIS. Results: Of 57 patients enrolled, 48 had complete follow up data. Median ATT-ART interval was 28 days (interquartile range, IQR 14–47). IRIS events occurred in 26 patients (54.2%) at a median of 11 days (IQR: 7–16) after ART initiation. Corticosteroids were required for treatment of most IRIS events that resolved within a median of 13 days (IQR: 9–23). Two patients died due to CNS TB-IRIS. Lower CD4+ T-cell counts, higher plasma HIV RNA levels, lower CD4/CD8 ratio, lower hemoglobin, shorter ATT to ART interval, extra-pulmonary or miliary TB and higher plasma IL-6 and CRP levels at baseline were associated with paradoxical TB-IRIS in the univariate analysis. Shorter ATT to ART interval, lower hemoglobin and higher IL-6 and CRP levels remained significant in the multivariate analysis. Conclusion: Paradoxical TB–IRIS frequently complicates HIV-TB therapy in India. IL-6 and CRP may assist in predicting IRIS events and serve as potential targets for immune interventions
Mycobacterial antigen driven activation of CD14++ CD16-monocytes is a predictor of tuberculosis-associated immune reconstitution inflammatory syndrome
Paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is an aberrant inflammatory response occurring in a subset of TB-HIV co-infected patients initiating anti-retroviral therapy (ART). Here, we examined monocyte activation by prospectively quantitating pro-inflammatory plasma markers and monocyte subsets in TB-HIV co-infected patients from a South Indian cohort at baseline and following ART initiation at the time of IRIS, or at equivalent time points in non-IRIS controls. Pro-inflammatory biomarkers of innate and myeloid cell activation were increased in plasma of IRIS patients pre-ART and at the time of IRIS; this association was confirmed in a second cohort in South Africa. Increased expression of these markers correlated with elevated antigen load as measured by higher sputum culture grade and shorter duration of anti-TB therapy. Phenotypic analysis revealed the frequency of CD14++CD16− monocytes was an independent predictor of TB-IRIS, and was closely associated with plasma levels of CRP, TNF, IL-6 and tissue factor during IRIS. In addition, production of inflammatory cytokines by monocytes was higher in IRIS patients compared to controls pre-ART. These data point to a major role of mycobacterial antigen load and myeloid cell hyperactivation in the pathogenesis of TB-IRIS, and implicate monocytes and monocyte-derived cytokines as potential targets for TB-IRIS prevention or treatment
Glycaemic index of Indian flatbreads (rotis) prepared using whole wheat flour and ‘atta mix’-added whole wheat flour
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas
Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
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