32 research outputs found

    Study of surface morphology, elemental composition and origin of atmospheric aerosols (PM2.5 and PM10) over Agra, India

    Get PDF
    In situ measurements of PM (PM2.5 and PM10) particles were carried out using a medium volume air sampler (offline) and particle number concentrations of PM were measured by a Grimm aerosol spectrophotometer (online) during the study period of 2010�2011. The morphology and elemental composition analyses of PM were performed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDS), respectively. The average mass concentrations of PM2.5 and PM10 were 97.2 and 242.6 µg/m3 at roadside (RD) and 121.2 and 230.5 µg/m3 at a semirural (SR) site, respectively. These concentrations were substantially higher than the NAAQS, WHO and USEPA standards. The highest mass and number concentrations of PM2.5 and PM10 were observed during winter, followed by those during the post-monsoon period and summer, with the lowest in the monsoon period. SEM and EDS analysis of PM indicated the presence of soot, mineral, tarballs, fly ash, aluminosilicates/silica, fluorine, carbon rich, and Cl-Na rich particles. Of these particles, soot, tarballs, and F-C rich particles dominate in PM2.5, whereas mineral, aluminosilicates, and Cl-Na rich particles dominate in PM10. The morphology and elemental composition of the particles varied over the seasons due to atmospheric processing. The highest carbon concentration (56) was observed in PM2.5 during summer at the RD, while in the monsoon, post-monsoon period and winter the carbon concentration was ~9 lower at the RD as compared to the SR. However, the concentration of carbon in PM10 was ~38 higher at the RD as compared to SR during both summer and winter. Air mass backward trajectory cluster analysis was performed, and the results indicate that the aerosol loadings over Agra are mainly transported from the Middle East and Arabian Sea during the summer and monsoon period, while during the pre-monsoon period and winter the aerosol loadings came from the northern region, and were due to the burning of biomass and coal, as well as other local activities

    Faecal calprotectin: factors affecting levels and its potential role as a surrogate marker for risk of development of Crohn's Disease.

    Get PDF
    BACKGROUND: Faecal calprotectin (FC) is one of the most widely used non-invasive tests for the diagnosis and assessment of Crohn's disease (CD) activity. Despite this, factors other than disease activity which affect levels have not been extensively reviewed. This is of importance when using FC in the diagnostic setting but also may be of utility in studying the aetiology of disease. OBJECTIVES: Our review outlines environmental risk factors that affect FC levels influencing diagnostic accuracy and how these may be associated with risk of developing CD. FC as a surrogate marker could be used to validate risk factors established in case control studies where prospective studies are not feasible. Proof of this concept is provided by our identification of obesity as being associated with elevated FC, our subsequent confirmation of obesity as risk factor for CD and the subsequent verification in prospective studies, as well as associations of lack of physical activity and dietary fibre intake with elevated FC levels and their subsequent confirmation as risk factors in prospective studies. CONCLUSION: We believe that FC is likely to prove a useful surrogate marker for risk of developing CD. This review has given a theoretical basis for considering the epidemiological determinants of CD which to date has been missing

    The immunobiology of primary sclerosing cholangitis

    Get PDF
    Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease histologically characterized by the presence of intrahepatic and/or extrahepatic biliary duct concentric, obliterative fibrosis, eventually leading to cirrhosis. Approximately 75% of patients with PSC have inflammatory bowel disease. The male predominance of PSC, the lack of a defined, pathogenic autoantigen, and the potential role of the innate immune system suggest that it may be due to dysregulation of immunity rather than a classic autoimmune disease. However, PSC is associated with several classic autoimmune diseases, and the strongest genetic link to PSC identified to date is with the human leukocyte antigen DRB01*03 haplotype. The precise immunopathogenesis of PSC is largely unknown but likely involves activation of the innate immune system by bacterial components delivered to the liver via the portal vein. Induction of adhesion molecules and chemokines leads to the recruitment of intestinal lymphocytes. Bile duct injury results from the sustained inflammation and production of inflammatory cytokines. Biliary strictures may cause further damage as a result of bile stasis and recurrent secondary bacterial cholangitis. Currently, there is no effective therapy for PSC and developing a rational therapeutic strategy demands a better understanding of the disease

    Sources and characteristics of carbonaceous aerosols at Agra World heritage site and Delhi capital city of India

    No full text
    Agra, one of the oldest cities “World Heritage site”, and Delhi, the capital city of India are both located in the border of Indo-Gangetic Plains (IGP) and heavily loaded with atmospheric aerosols due to tourist place, anthropogenic activities, and its topography, respectively. Therefore, there is need for monitoring of atmospheric aerosols to perceive the scenario and effects of particles over northern part of India. The present study was carried out at Agra (AGR) as well as Delhi (DEL) during winter period from November 2011 to February 2012 of fine particulate (PM2.5: d < 2.5 μm) as well as associated carbonaceous aerosols. PM2.5 was collected at both places using medium volume air sampler (offline measurement) and analyzed for organic carbon (OC) and elemental carbon (EC). Also, simultaneously, black carbon (BC) was measured (online) at DEL

    CCR5-Delta 32 mutation is strongly associated with primary sclerosing cholangitis

    No full text
    CCR5 plays a key role in the distribution of CD45RO+ T cells and contributes to generation of a T helper 1 immune response. CCR5-Delta32 is a 32-bp deletion associated with significant reduction in cell surface expression of the receptor. We investigated the role of CCR5-Delta32 on susceptibility to ulcerative colitis (UC), Crohn's disease ( CD) and primary sclerosing cholangitis (PSC). Genotype and allelic association analyses were performed in 162 patients with UC, 131 with CD, 71 with PSC and 419 matched controls. There was a significant difference in CCR5 genotype (OR 2.27, P = 0.003) between patients with sclerosing cholangitis and controls. Similarly, CCR5-Delta32 allele frequency was significantly higher in sclerosing cholangitis (17.6%) compared to controls (9.9%, OR 2.47, P = 0.007) and inflammatory bowel disease patients without sclerosing cholangitis ( 11.3%, OR 1.9, P = 0.027). There were no significant differences in CCR5 genotype or allele frequency between those with either UC or CD and controls. Genotypes with the CCR5-Delta32 variant were increased in patients with severe liver disease defined by portal hypertension and/or transplantation (45%) compared to those with mild liver disease (21%, OR 3.17, P = 0.03). The CCR5-Delta32 mutation may influence disease susceptibility and severity in patients with PSC
    corecore