EFFECT OF SOLUTIONISING TIME ON MECHANICAL PROPERTIES OF SQUEEZE CASTED AL 6082 – SICP COMPOSITE

Aluminum matrix composites refer to the class of light weight high performance aluminum centric material systems. The unique tailorability of the composite materials for the specific requirements makes these materials more popular in a variety of applications such as aerospace, automotive (pistons, cylinders, liners, bearings), and structural components, resulting in savings of material and energy. In this project, fabrication of Aluminum MMC by liquid metallurgy route (Squeeze Casting) is discussed in detail. The mechanical properties of 6082 aluminum alloy discontinuously – reinforced with fine particulates of SiCp reinforcement and solutionising time during heat treatment of the composite on hardness, density and impact strength have been evaluated. The cardinal reasons behind the variation in the hardness and impact strength have been discussed

G2-structures for N=1 supersymmetric AdS4 solutions of M-theory

We study the N=1 supersymmetric solutions of D=11 supergravity obtained as a warped product of four-dimensional anti-de-Sitter space with a seven-dimensional Riemannian manifold M. Using the octonion bundle structure on M we reformulate the Killing spinor equations in terms of sections of the octonion bundle on M. The solutions then define a single complexified G2-structure on M or equivalently two real G2-structures. We then study the torsion of these G2-structures and the relationships between them.Comment: 48 pages, updated references, corrected minor errors and typos, Class. Quantum Grav. (2018

HLA-DR and -DQ antibodies in the sera of South India Parous women

HLA-A, -B positive sera of south Indian parous women were screened for the presence of HLA-DR and -DQ antibodies. The sera were absorbed with pooled platelets in a micro-method and screened against HLA-DR and -DQ typed B-lymphocytes panel. Out of fifty two sera, twenty were found to contain HLA-DR and -DQ antibodies. Seven sera were demonstrated to be specific for well defined DR and DQ antigen

Survelliance of drug resistance in tuberculosis in the state of Tamil Nadu

Summary: Surveillance of drug resistance was carried out at State level to obtain data which are standardised and comparable using guidelines prescribed by the WHO/IUATLD Working Group on Anti-tuberculosis Drug Resistance Surveillance. Objective: To determine the proportion of initial and acquired drug resistance in cases of pulmonary tuberculosis in Tamilnadu, in order to use the level of drug resistance as a performance indicator of the National Tuberculosis Programme. Methods: Two specimens of sputum from each of a total of 713 patients attending 145 participating centres all over the state were tested by smear and culture examination and drug susceptibility tests of Isoniazid, Rifampicin, Ethambutol and Streptomycin. Results: Out of 400 patients for whom drug susceptibility results were available, 384 (96%) had no history of previous anti-tuberculosis treatment. Of these, 312 (81%) were susceptible to all the drugs tested. Resistance to isoniazid was seen in 15.4% of patients and to Rifampicin in 4.4% including resistance to Isoniazid and Rifampicin in 3.4%. Conclusion: There has been a gradual increase in initial drug resistance over the years in this part of the country

Bioluminescence assay of adenosine triphosphate in drug susceptibility testing of Mycobacterium tuberculosis

Twenty three clinical isolates of M. tuberculosis and the reference strain, M. tuberculosis H37Rv were tested for their susceptibility to trifluoperazine (TFP) by the standard broth dilution method and the bioluminescence assay. The results showed that in 15 of the 23 isolates, the minimal inhibitory concentration (MIC) was identical in both the methods and in the remaining 8 isolates the difference in the MIC values between the methods, was less than two fold and was not significant. The findings suggest that the measurement of adenosine triphosphate (ATP) by bioluminescence assay can be employed as an alternative method for the rapid screening of clinical isolates for their susceptibility to anti-mycobacterial agents

Super-resolution, Extremal Functions and the Condition Number of Vandermonde Matrices

Super-resolution is a fundamental task in imaging, where the goal is to extract fine-grained structure from coarse-grained measurements. Here we are interested in a popular mathematical abstraction of this problem that has been widely studied in the statistics, signal processing and machine learning communities. We exactly resolve the threshold at which noisy super-resolution is possible. In particular, we establish a sharp phase transition for the relationship between the cutoff frequency ($m$) and the separation ($\Delta$). If $m > 1/\Delta + 1$, our estimator converges to the true values at an inverse polynomial rate in terms of the magnitude of the noise. And when $m < (1-\epsilon) /\Delta$ no estimator can distinguish between a particular pair of $\Delta$-separated signals even if the magnitude of the noise is exponentially small. Our results involve making novel connections between {\em extremal functions} and the spectral properties of Vandermonde matrices. We establish a sharp phase transition for their condition number which in turn allows us to give the first noise tolerance bounds for the matrix pencil method. Moreover we show that our methods can be interpreted as giving preconditioners for Vandermonde matrices, and we use this observation to design faster algorithms for super-resolution. We believe that these ideas may have other applications in designing faster algorithms for other basic tasks in signal processing.Comment: 19 page

Estimation of burden of tuberculosis in India for the year 2000

Background & objectives: Data on the burden of tuberculosis (TB) in India are vital for programme planners to plan the resource requirements and for monitoring the nation-wide TB control programme. There was a need to revise the earlier estimate on the burden of TB in India based on the increase in population and current epidemiological data. This study estimates the burden of disease for the year 2000 based on recent prevalence of TB and annual risk of tuberculosis infection (ARTI) estimates. Methods: Data on prevalence generated among adults by the Tuberculosis Research Centre (TRC), Chennai, among children by National Tuberculosis Institute (NTI), Bangalore, and the ARTI estimates from the nation-wide sample survey by NTI and TRC were used for the estimation. The prevalence of disease corresponding to 1 per cent ARTI was extrapolated to different parts of the country using the estimates of ARTI and the population in those areas and added together to get the total cases. Abacillary cases that required treatment were estimated from X-ray abnormals. The estimates of bacillary, abacillary and extrapulmonary cases were then combined to get the national burden. Results: The estimated number of bacillary cases was 3.8 million (95% CI: 2.8 - 4.7). The number of abacillary cases was estimated to be 3.9 million and that for extrapulmonary cases was 0.8 million giving a total burden of 8.5 million (95% CI: 6.3-10.4) for 2000. Interpretation & conclusion: The present estimate differs from the earlier estimates because we have included the disease burden of X-ray cases that are likely to breakdown to bacillary cases in a one year period, and extrapulmonary TB cases. The current estimates provided baseline information for advocacy and planning resource allocation for TB control activities. Also, these estimates can be compared with that in future years to measure the long term impact of TB control activities in India

Evaluation of Directly Observed Treatment providers in the revised national tuberculosis control programme

Background: Non-governmental personnel such as Anganwadi workers and community volunteers have been used as directly observed treatment (DOT) providers in the Revised National Tuberculosis Control Programme (RNTCP), but their effectiveness has not been documented. Aim: To assess the treatment outcome and problems encountered by patients managed by different DOT providers in the RNTCP. Material and Methods: Patients diagnosed with tuberculosis at 17 Primary Health Institutions (PHIs) in Tiruvallur District during a 3-year period received DOT from one of the four types of trained DOT providers (PHI staff, governmental outreach workers, Anganwadi workers, community volunteers), and their treatment outcomes were compared. Of the 1131 new smear-positive patients treated between May 1999 through June 2002, 199 (18%) received DOT from PHI staff, 238(21%) from outreach workers, 496 (44%) from Anganwadi workers, and 170 (15%) from community volunteers. Twenty-eight patients (2%) collected drugs for self-administration. Results: Treatment success rates among patients treated by different DOT providers, Anganwadi workers (80%), governmental outreach workers (81%), community volunteers (76%) and PHI staff (76%), were statistically similar. Patients who received drugs for self-administration were significantly more likely to fail to treatment or die than patients who were treated by a DOT provider (5/28 versus 84/1103; odds ratio=4.1; 95% confidence interval=1.2-12.6; p=0.02). Conclusion: In addition to governmental staff, Anganwadi workers and community volunteers can be effectively utilized as DOT providers

Surveillance of drug-resistant tuberculosis in the state of Gujarat, India

BACKGROUND: Limited information about the prevalence of drug-resistant tuberculosis (TB) has been reported from India, the country with the world’s highest burden of TB. We conducted a representative state-wide survey in the state of Gujarat (2005 population: 56 million). METHODS: Mycobacterium tuberculosis isolates from a representative sample of new and previously treated smear-positive pulmonary TB (PTB) cases were subjected to drug susceptibility testing (DST) against fi rst-line drugs at a World Health Organization supranational reference laboratory. Isolates found to have at least both isoniazid (INH) and rifampicin (RMP) resistance (i.e., multidrugresistant TB [MDR-TB]) were subjected to second-line DST. RESULTS: Of 1571 isolates from new patients, 1236 (78.7%) were susceptible to all fi rst-line drugs, 173 (11%) had any INH resistance and MDR-TB was found in 37 (2.4%, 95%CI 1.6–3.1). Of 1047 isolates from previously treated patients, 564 (54%) were susceptible to all fi rst-line drugs, 387 (37%) had any INH resistance and MDR-TB was found in 182 (17.4%, 95%CI 15.0–19.7%). Among 216 MDR-TB isolates, 52 (24%) were ofl oxacin (OFX) resistant; seven cases of extensively drug-resistant TB (XDR-TB) were found, all of whom were previously treated cases. CONCLUSION: MDR-TB prevalence remains low among new TB patients in Gujarat, but is more common among previously treated patients. Among MDR-TB isolates, the alarmingly high prevalence of OFX resistance may threaten the success of the expanding efforts to treat and control MDR-TB