Disease mapping using mixture distribution

Background & objectives: Data on infectious diseases like tuberculosis (TB) have been analyzed in the past without giving adequate attention to spatial variations. Earlier studies also attempted to display disease status of sub regions, usually census tracts, by categorizing them into quartiles, that helps the authorities to identify high- or low-risk areas. This approach is based mainly on binomial and Poisson models for disease data, and the recent attempts focus on using mixture models of Poisson distribution. We carried out this study to find wards of Madurai Corporation having high risks for TB disease, to develop a model of mixture of Poisson distributions for the number of cases and to classify each ward to one of many risk groups for TB disease, and to represent spatial distribution of TB incidence in Madurai city. Methods: Mixture models were used in finding the number of risk groups which might have produced the observed counts of TB patients in 72 wards of Madurai Corporation. The number of risk groups and the Poisson parameters of each group were found by maximum likelihood approach using the computer package C.A.MAN (Computer Assisted Mixture ANalysis). Bayesian methods were used to associate each ward to a particular risk group. The results were geographically presented in maps by using ArcView mapping software. Results: Using binomial model, 26 wards were categorized as high risk wards, and with mixture model approach 15 wards showed standardized morbility ratio (SMR) >1. The wards along river Vaigai and densely populated wards had high risk. Interpretation & conclusion: Our findings demonstrate the usefulness of the mixture models for disease data with geographical variations

Comparison of NALC-NAOH processing method with C18-carboxy propyl betaine method for the detection of mycobacterium in sputum

Background: Tuberculosis is an infectious disease which remains to be a major public health risk worldwide even after the availability of many highly sensitive diagnostic tools. Early case detection plays an important role in control of the disease which relies solely on the detection of acid-fast bacilli in clinical samples which is low sensitive. Prior decontamination of sputum sample may improve the detection of mycobacterium.Methods: A prospective study was conducted with a total of (N=464) clinically suspected TB patient sputum samples which were collected and processed directly for AFB. From which AFB +ve samples were excluded. The direct AFB-ve (N=279) samples were processed using concentration (NALC, CB-18) and culture (LJ medium). After concentration, smears were examined under oil immersion for acid fast bacilli by ZN staining.Results: Out of 464 sputum samples, 185 direct ZN stain +ve were excluded. Among the ZN-ve (N=279) samples, N= 48 (17.2%) were positive using NALC-NaOH method. The positivity has improved to N=69 (25%) using CB-18 and N=79 (28.3%) using culture (LJ medium).Conclusions: CB-18 is sensitive than NALC-NaOH method and its sensitivity is almost comparable to the gold standard culture using LJ medium. Therefore we conclude that the identification of AFB using CB-18 concentration method can be used in resource limited health care setups which might help us to diagnose the TB at the earliest

Conformational energy map of a dipeptide unit in relation to infrared and nuclear magnetic resonance data

This article does not have an abstract

Catalytic epoxidation of cyclic vinylsilanes by ruthenium(II) complexes under aerobic conditions

A new methodology has been developed for the catalytic epoxidation of cyclic vinylsilanes using a ruthenium(II) bisoxazoline complex 2 with molecular oxygen. An attempt has been made to understand the role of -SiMe3 group on the rate of epoxidation process. © 2003 Elsevier Ltd. All rights reserved

Propargyloxycarbonyl (Poc) amino acid chlorides as efficient coupling reagents for the synthesis of 100% diastereopure peptides and resin bound tetrathiomolybdate as an effective deblocking agent for the Poc group

Synthesis of short peptides using propargyloxycarbonyl amino acid chlorides as effective coupling reagents and polymer supported tetrathiomolybdate as an efficient deblocking agent are reported

Learning through projects in engineering education

[No abstract available

Antibacterial activity of diff erent solvent extracts of Caulerpa chemnitzia (Esper) J.V. Lamououx, from Mandapam, Gulf of Mannar Southeast Coast, Tamil Nadu, India

Phytochemical analyses and in vitro antibacterial activity of different extracts of hexane, chloroform, ethyl acetate,acetone, and methanol extracts of green algae, Caulerpa chemnitzia (Esper) J.V. Lamououx, against Bacillussubtilis, Streptococcus pyogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris,Pseudomonas aeruginosa, Salmonella typhimurium, Shigella flexneri, and Vibrio cholerae. The extent of theinhibitory zone, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) weredetermined. The ethyl acetate extract of C. chemnitzia showed the presence of phytochemicals, terpenoids,tannins and phenolic compounds strongly than the other solvent extracts. The mean zone of inhibition producedby the extracts in agar diffusion assays against the tested bacterial strains ranged from 7.1 to 13.6 mm. The MICwas between 125 and 500 μg/mL while the MBC were between 250 and 1000 μg/mL. The highest mean zoneof inhibition (13.6 mm) and the lowest MIC (125 μg/mL) and MBC (250 μg/mL) values were observed in ethylacetate extract against B. subtilis. These findings suggest that the ethyl acetate extract of C. chemnitzia can beused as an antibacterial substance for the treatment of bacteria causing acquired infection

Screening of phytochemical and antibacterial potential of diff erent organic solvent extracts of Stoechospermum marginatum (Ag) Kutz. from Manappad coast, Tuticorin District, South India

The antibacterial activity of different extracts of hexane, chloroform, ethyl acetate, acetone and methanol extractof a brown alga, Stoechospermum marginatum (Ag) Kutz. against Bacillus subtilis, Streptococcus pyogenes,Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa, Salmonellatyphimurium, Shigella flexneri and Vibrio cholerae. The extent of the inhibitory zone, Minimum InhibitoryConcentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined. The ethyl acetateextract of S. marginatum showed the highest antibacterial activity against all the bacterial strains tested thanthe other extracts. The mean zones of inhibition produced by the extracts in agar diffusion assays against thetested bacterial strains ranged from 7.1 to 18.1 mm. The MIC were between 125 and 500 μg/ml, while theMBC were between 250 and 1000 μg/ml. The ethyl acetate extract of S. marginatum showed the presenceof terpenoids, tannins, phenolic compounds and steroids strongly than the other solvent extracts. The highestmean of zone inhibition (18.1 mm) was observed in the ethyl acetate extract of S. marginatum against B. subtilis.These finding suggest that the ethyl acetate extract of S. marginatum can be used as an antibacterial substancefor the treatment of bacterial infections