Vapor-liquid equilibrium in a polysulfone-reactive plasticizer-dichloromethane system

Vita.A piezoelectric sorption apparatus is used to study the sorption of dichloromethane (DCM) in a polysulfone (PSF), a reactive plasticizer (RPS), and a mixture containing 70 wt. % PSF and 30 wt. % RPS. A general procedure is suggested to model the sorption data in the glassy polymer. The "dual sorption" model is used to find the hole-filling and dissolution contributions for DCM sorption in PSF. The Flory-Huggins theory and the Cheng and Bonner corresponding states theory are applied to model the dissolution contribution for sorption of DCM in PSF and the sorption of DCM in RPS. The data obtained for the sorption of DCM in PSF from the piezoelectric sorption technique and the infinite dilution chromatography are compared. An extension of the Cheng and Bonner corresponding states theory to three components is proposed. The sorption of DCM in the mixture of PSF and RPS is modelled by Scott's theory and the extension of the Cheng and Bonner theory to three components to provide information about the PSF and RPS compatibility

Vapor-liquid equilibrium in a polysulfone-reactive plasticizer-dichloromethane system

Vita.A piezoelectric sorption apparatus is used to study the sorption of dichloromethane (DCM) in a polysulfone (PSF), a reactive plasticizer (RPS), and a mixture containing 70 wt. % PSF and 30 wt. % RPS. A general procedure is suggested to model the sorption data in the glassy polymer. The "dual sorption" model is used to find the hole-filling and dissolution contributions for DCM sorption in PSF. The Flory-Huggins theory and the Cheng and Bonner corresponding states theory are applied to model the dissolution contribution for sorption of DCM in PSF and the sorption of DCM in RPS. The data obtained for the sorption of DCM in PSF from the piezoelectric sorption technique and the infinite dilution chromatography are compared. An extension of the Cheng and Bonner corresponding states theory to three components is proposed. The sorption of DCM in the mixture of PSF and RPS is modelled by Scott's theory and the extension of the Cheng and Bonner theory to three components to provide information about the PSF and RPS compatibility

Surveillance of vibriophages reveals their role as biomonitoring agents in Kolkata

Cholera is a public health threat in all developing countries. Kolkata, a city in eastern India, is an endemic zone for cholera. During the course of a comprehensive investigation on the distribution of phages of Vibrio cholerae O1 and O139 in freshwater bodies in Kolkata, we were able to isolate the phages of V. cholerae O1 and O139. Vibrio cholerae O1 phages were found at all the sites and exhibited a distinct seasonal cycle, with a primary peak (13.6-17.2 PFU mL<SUP>-1</SUP>) during monsoon (June to August) in both 2006 and 2007. Vibrio cholerae O139 phages were present in the environment and were predominant during monsoon in the year 2006, except for late winter and early summer from February to April. In contrast, in the year 2007, the O139 phages could be isolated only during July to December, with the highest counts of 12.0 PFU mL<SUB>-1</SUB> determined in August. The multiplex PCR results showed that 90 samples were positive for wbe of V. cholerae O1, 32 samples for O139 (wbf) and 18 samples for both. This study shows that surveillance of vibriophages indicates the presence of V. cholerae O1 and O139 in water bodies in and around Kolkata and could therefore serve as a powerful biomonitoring agent

Typing and antibiogram of Vibrio cholerae isolates from a tertiary care hospital in Pune: A 3 year study

A retrospective analysis was done over a period of 3 years (January 2010- December 2012) in a tertiary care hospital, Pune, to note the changes in the prevalence and distribution of biotypes, serotypes, antibiotic susceptibility pattern and phage types of Vibrio cholerae isolates from clinical samples so as to be vigilant and curtail major outbreak in future. Vibrio cholerae isolates were obtained from 4.4% of the 1126 fecal specimens processed from cases of acute watery diarrhea. Majority of the isolates were identified as V. cholerae O1 biotype El Tor serotype Ogawa (98%); Phage 27 was the predominant type (77.5%). Majority of the cases were encountered during the months June-August (68%). Antibiogram over a period of 3 years showed that isolates were consistently resistant to Ampicillin (90%) and Furazolidone (88%). Low level of resistance was seen with Norfloxacin (8%), Gentamicin (8%) and Tetracycline (6%). All isolates were susceptible to Chloramphenicol

Seasonal dynamics of Vibrio cholerae and its phages in riverine ecosystem of Gangetic West Bengal: cholera paradigm

The Gangetic delta is a century-old cholera endemic belt where the role of riverine–estuarine ecosystem in cholera transmission has never been elucidated. Seasonality, distribution, and abundance of environmental Vibrio cholerae O1/O139 and vibriophage in Hooghly riverine–estuarine environment and their correlation with cholera incidence pattern in West Bengal, India, have been analyzed for the first time across summer, monsoon, and winter months. A total of 146 water samples collected from two sites of the Hooghly River (Howrah and Diamond Harbour) were analyzed physicochemically along with cultivable Vibrio count (CVC), V. cholerae O1/O139, and vibriophages. V. cholerae O1 was detected in 56 (38.3 %) samples, while 66 (45.2 %) were positive for V. cholerae O1 phages. Flood tide, water temperature (31 ± 1.6 °C), and turbidity (≥250 nephelometric turbidity unit (NTU)) significantly stimulated V. cholerae and vibriophage abundance in riverine ecosystem. Solitary existence of V. cholerae O1 and phages (p < 0.0001) in aquatic environment divulges the dominance of either of the entity (V. cholerae O1 or V. cholerae O1 Φ) on the other. Significant association (p < 0.05) between Kolkata cholera cases and V. cholerae O1 in aquatic environment implies the role of riverine–estuarine ecosystem in cholera transmission. A “biomonitoring tool” of physicochemical stimulants, tidal, and climatic variants has been proposed collating V. cholerae and phage dynamics that can forewarn any impending cholera outbreak.Fil: Mookerjee, Subham. National Institute For Cholera And Enteric Diseases; IndiaFil: Jaiswal, Abhishek. National Institute For Cholera And Enteric Diseases; IndiaFil: Batabyal, Prasenjit. National Institute For Cholera And Enteric Diseases; IndiaFil: Einsporn, Marc H.. Centre For Tropical Marine Ecology; AlemaniaFil: Lara, Ruben Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto Argentino de Oceanografía (i); Argentina. Centre For Tropical Marine Ecology; AlemaniaFil: Sarkar, Banwarilal. National Institute For Cholera And Enteric Diseases; IndiaFil: Neogi, Sucharit Basu. Osaka Prefecture University; Japón. International Centre for Diarrheal Disease Research; BangladeshFil: Palit, Anup. National Institute For Cholera And Enteric Diseases; Indi

Vibrio cholerae O1 clinical strains isolated in 1992 in Kolkata with progenitor traits of the 2004 Mozambique variant

Retrospective analysis led to the detection of two Vibrio cholerae variant O1 strains (VC51 and VC53), which were isolated in 1992 in Kolkata from clinical cases, with identical traits to 2004 Mozambique variant O1 strains. The Mozambique O1 strains that caused a huge outbreak in 2004 have been shown to have phenotypic traits of both classical and El Tor biotypes, and thereby have been reported as variant. Our study demonstrated that two O1 strains isolated in Kolkata during 1992 were of the El Tor background as evidenced by polymyxin B (50 U ml”1) resistance, positivity in Voges–Proskauer reactions and sensitivity to biotype-specific vibrio phages. With the features of classical CTX prophage, localization in the small chromosome, and an absence of RS1 and pTLC, both Mozambique and Kolkata strains appeared to be identical. Furthermore, two Kolkata strains exhibited an identical ribotype to that of the Mozambique variant, displaying ribotype pattern RI that had been assigned to Kolkata V. cholerae O1 strains isolated on or before 1992. NotI pulsotype analysis indicated that these 1992 Kolkata strains along with the Mozambique variant O1 belonged to very closely related clones. Considering the chronological events, and the typical identity at the phenotypic and the genotypic level between the two O1 strains isolated during 1992 from Kolkata and during 2004 from Mozambique, we propose that some of the 1992 Kolkata O1 strains might have acted as progenitors for Mozambique variant O1 strains

Clinical, epidemiological, and spatial characteristics of <it>Vibrio parahaemolyticus</it> diarrhea and cholera in the urban slums of Kolkata, India

<p>Abstract</p> <p>Background</p> <p>There is not much information on the differences in clinical, epidemiological and spatial characteristics of diarrhea due to <it>V. cholerae</it> and <it>V. parahaemolyticus</it> from non-coastal areas. We investigated the differences in clinical, epidemiological and spatial characteristics of the two <it>Vibrio</it> species in the urban slums of Kolkata, India.</p> <p>Methods</p> <p>The data of a cluster randomized cholera vaccine trial were used. We restricted the analysis to clusters assigned to placebo. Survival analysis of the time to the first episode was used to analyze risk factors for <it>V. parahaemolyticus</it> diarrhea or cholera. A spatial scan test was used to identify high risk areas for cholera and for <it>V. parahaemolyticus</it> diarrhea.</p> <p>Results</p> <p>In total, 54,519 people from the placebo clusters were assembled. The incidence of cholera (1.30/1000/year) was significantly higher than that of <it>V. parahaemolyticus</it> diarrhea (0.63/1000/year). Cholera incidence was inversely related to age, whereas the risk of <it>V. parahaemolyticus</it> diarrhea was age-independent. The seasonality of diarrhea due to the two <it>Vibrio</it> species was similar. Cholera was distinguished by a higher frequency of severe dehydration, and <it>V. parahaemolyticus</it> diarrhea was by abdominal pain. Hindus and those who live in household not using boiled or treated water were more likely to have <it>V. parahaemolyticus</it> diarrhea. Young age, low socioeconomic status, and living closer to a project healthcare facility were associated with an increased risk for cholera. The high risk area for cholera differed from the high risk area for <it>V. parahaemolyticus</it> diarrhea.</p> <p>Conclusion</p> <p>We report coexistence of the two vibrios in the slums of Kolkata. The two etiologies of diarrhea had a similar seasonality but had distinguishing clinical features. The risk factors and the high risk areas for the two diseases differ from one another suggesting different modes of transmission of these two pathogens.</p