Self-Compacting Concrete - Robustness of SCC

Self-compacting concrete (SCC) is an innovative concrete that does not require vibration for placing and compaction. It is able to flow under its own weight, completely filling formwork and achieving full compaction, even in the presence of congested reinforcement. In the sense of SCC the robustness can be defined as the property that resist the changes of SCC like segregation during and placement (dynamic stability) and post placement (static stability). In a broader and more practical sense robustness as the ability of a given mixture to maintain its fresh properties and uniformity during processing, casting

Simple Direct Drug Susceptibility Tests on Sputum Samples for Early Detection of Resistance in Tubercle Bacilli

Background: Direct sensitivity test either by sputum concentrate (DS) or swab method (DSM) set up along with the primary culture would avoid the delay of four or more weeks required for the indirect test. A comparison of these two methods against the standard indirect sensitivity method under routine laboratory conditions is necessary to prove their merit. Method: Smear positive sputum samples were aliquoted and sensitivity tests were set up by both the direct methods as also an indirect test set up from the primary culture of the same sample. Results: The agreement with the indirect test results for isoniazid (INH) ranged from 97-98% for the DS method and 93- 97% for the DSM method. The corresponding figures were 96-98% by the DS and 94-99% by the DSM method for rifampicin (R). The agreement was less satisfactory for ethambutol (Emb). Conclusion: This study showed that direct sensitivity tests such as DS and DSM methods can detect most of the cultures resistant to INH and R (MDR) from the time growth appears on the primary culture , even as early as the second week of setting up the tests

Comparison of different methods of assessing in vitro resistance of Mycobacterium tuberculosis to rifampicin

Background & objectives: Definitions of in vitro resistance to rifampicin in. strains of Mycobacterium tuberculosis by different methods have not been consistent, leading to variations in the interpretation and validity of results. This study compared three methods of defining in vitro resistance to rifampicin. Methods: (i) A total of 598 clinical isolates of M. tuberculosis were concurrently compared by the minimal inhibitory concentration (MIC) and the proportion method on Lowenstein-Jensen medium; (ii) 54 strains tested by the MIC method were retested by the proportion method and the BACTEC radiometric method; and (iii) 72 strains which yielded an MIC of 64 mg/l by the MIC method were retested by the same method. Results: Out of 598 cultures tested by the MIC and the proportion methods, identical classification as susceptible or resistant was observed in 99.7 per cent. A 100 per cent agreement was observed when 54 strains were tested by the MIC, proportion and BACTEC radiometric methods. When 72 strains with an MIC of 64 mg/l were retested by the same method, 61 (85%) yielded a lower MIC, 9 (12%) gave the same MIC while 2 (3%) yielded a higher MIC of 128 mg/l, reflecting perhaps the inherent limitations of the variations in the inoculum size. Interpretation & conclusion: All 3 definitions of resistance, viz., an MIC of 128 mg/l, a proportion of I per cent or more on 40 mg/l by the proportion method, both on L-J medium and a growth of 1 per cent or more on 2 mg/l by the radiometric method were found to be equally satisfactory

On non-QRT Mappings of the Plane

We construct 9-parameter and 13-parameter dynamical systems of the plane which map bi-quadratic curves to other bi-quadratic curves and return to the original curve after two iterations. These generalize the QRT maps which map each such curve to itself. The new families of maps include those that were found as reductions of integrable lattices

Management of Multi Drug Resistance Tuberculosis in the Field: Tuberculosis Research Centre Experience

Setting: Multi-drug TB resistant (resistant to isoniazid and rifampicin) patients identified from a rural and urban area. Objective: To study the feasibility of managing MDR TB patients under field conditions where DOTS programme has been implemented Methods: MDR TB Patients identified among patients treated under DOTS in the rural area and from cases referred by the NGO when MDR TB was suspected form the study population. Culture and drug susceptibility testing were done at Tuberculosis Research Centre (TRC). Treatment regimen was decided on individual basis. After a period of initial hospitalization, treatment was continued in the respective peripheral health facility or with the NGO after identifying a DOT provider in the field. Patients attended TRC at monthly intervals for clinical, sociological and bacteriological evaluations. Drugs for the month were pre-packed and handed over to the respective center. Results: A total of 66 MDR TB patients (46 from the rural and 20 from the NGO) started on treatment form the study population and among them 20 (30%) were resistant to one or more second line drugs (Eto, Ofx, Km) including a case of “XDR TB”. Less than half the patients stayed in the hospital for more than 10 days. The treatment was provided partially under supervision. Providing injection was identified to be a major problem. Response to treatment could be correctly predicted based on the 6-month smear results in 40 of 42 regular patients. Successful treatment outcome was observed only in 37% of cases with a high default of 24%. Adverse reactions necessitating modification of treatment was required only for three patients. Implications Despite having reliable DST and drug logistics, the main challenge was to maintain patients on such prolonged treatment by identifying a provider closer to the patient who can also give injection, have social skills and manage of minor adverse reactions

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

Mappings preserving locations of movable poles: a new extension of the truncation method to ordinary differential equations

The truncation method is a collective name for techniques that arise from truncating a Laurent series expansion (with leading term) of generic solutions of nonlinear partial differential equations (PDEs). Despite its utility in finding Backlund transformations and other remarkable properties of integrable PDEs, it has not been generally extended to ordinary differential equations (ODEs). Here we give a new general method that provides such an extension and show how to apply it to the classical nonlinear ODEs called the Painleve equations. Our main new idea is to consider mappings that preserve the locations of a natural subset of the movable poles admitted by the equation. In this way we are able to recover all known fundamental Backlund transformations for the equations considered. We are also able to derive Backlund transformations onto other ODEs in the Painleve classification.Comment: To appear in Nonlinearity (22 pages

Squeezing of a coupled state of two spinors

The notion of spin squeezing involves reduction in the uncertainty of a component of the spin vector below a certain limit. This aspect has been studied earlier for pure and mixed states of definite spin. In this paper, this study has been extended to coupled spin states which do not possess sharp spin value. A general squeezing criterion has been obtained by requiring that a direct product state for two spinors is not squeezed. The squeezing aspect of entangled states is studied in relation to their spin- spin correlations.Comment: Typeset in LaTeX 2e using the style iopart, packages iopams,times,amssymb,graphicx; 17 pages, 5 eps figure file