Browsing by Subject "Ozone"

Now showing 1 - 4 of 4
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    Associations between air pollution indicators and prevalent and incident diabetes in an African American cohort, the Jackson Heart Study
    (Wolters Kluwer, 2021-04-22) Weaver, Anne M.; Bidulescu, Aurelian; Wellenius, Gregory A.; Hickson, DeMarc A.; Sims, Mario; Vaidyanathan, Ambarish; Wu, Wen-Chih; Correa, Adolfo; Wang, Yi; Environmental Health Science, School of Public Health
    Background: Diabetes is especially prevalent among African Americans. Prior studies suggest that long-term exposure to ambient air pollution may be associated with greater incidence of diabetes, but results remain heterogeneous. Few studies have included large numbers of African Americans. Methods: We assessed diabetes status and concentrations of 1- and 3-year fine particulate matter (PM2.5) and ozone (O3) among African American participants of the Jackson Heart Study at visits 1 (2000-2004, N = 5128) and 2 (2005-2008, N = 2839). We used mixed-effect modified Poisson regression to estimate risk ratios (RRs) and 95% confidence intervals (CIs) of incidence of diabetes by visit 2 and prevalence ratios (PRs) of the association between air pollution exposure and prevalent diabetes at visits 1 and 2. We adjusted for potential confounding by patient characteristics, as well as inverse probability weights of diabetes at visit 2, accounting for clustering by census tract. Results: We observed associations between incident diabetes and interquartile range increase in 1-year O3 (RR 1.34, 95% CI = 1.11, 1.61) and 3-year O3 (RR 0.88, 95% CI = 0.76, 1.02). We observed associations between prevalent diabetes and 1-year PM2.5 (PR 1.08, 95% CI = 1.00, 1.17), 1-year O3 (PR 1.18, 95% CI = 1.10, 1.27), and 3-year O3 (PR 0.95, 95% CI = 0.90, 1.01) at visit 2. Conclusions: Our results provide some evidence of positive associations between indicators of long-term PM2.5 and O3 exposure and diabetes. This study is particularly relevant to African Americans, who have higher prevalence of diabetes but relatively few studies of environmental pollution risk factors.
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    Effectiveness of ozonated water irrigation against an established Enterococcus faecalis biofilm in root canal treated teeth in vitro
    (2020) Broady, Adam B.; Spolnik, Kenneth J.; Duarte, Simone; Gossweiler, Ana; Bringas, Josef S.; Ehrlich, Ygal
    Introduction: One of the main objectives of endodontic therapy is to reduce microbes and remove inflamed pulpal tissue within the root canal system (RCS). This is accomplished through chemomechanical debridement of the RCS using hand and rotary instrumentation along with an antimicrobial irrigant. Today, the most commonly used irrigant is sodium hypochlorite (NaOCl), often at concentrations toxic to human cells. The use of ozone as an endodontic irrigant is a novel technique that has been proven to be antimicrobial against several microorganisms. However, independent research is lacking on ozone’s efficacy against an established endodontic biofilm. If ozone’s efficacy against biofilms is confirmed, the use of toxic and potentially dangerous sodium hypochlorite could be replaced in some clinical situations (i.e., regeneration, immature teeth, resorption) with a safer and effective alternative. Objective: The aim of the current study was to evaluate the anti-biofilm activity of different concentrations of ozonated water compared to various concentrations of NaOCl against an established endodontic biofilm of Enterococcus faecalis in root canal treated teeth in vitro. Materials and Methods: The crowns of similarly sized, maxillary anterior teeth were removed, and the roots cut to a standard length (12 mm). All root canals were instrumented to a standard size. Specimens were sterilized and then inoculated with E. faecalis, which were allowed to grow for two weeks to form an established biofilm. There were six treatment groups: 1) 6% NaOCl; 2) 1.5% NaOCl; 3) 16µg/mL ozonated water; 4) 25µg/mL ozonated water; 5) 50µg/mL ozonated water, and 6) saline. Following treatment, samples were collected, plated, and incubated for two days. The number of CFU/mL were determined, and samples visualized using confocal imaging. The effect of treatment group on bacterial counts was made using one-way ANOVA followed by pair-wise comparisons. Null Hypothesis: Endodontically treated teeth irrigated with ozonated water will not demonstrate a statistically significant decrease in the E. faecalis biofilm compared to those treated with sodium hypochlorite Results: CFUs were converted to log10 and compared using Fisher’s Exact tests or one-way ANOVA followed by pair-wise tests. In all observations utilizing NaOCl irrigation, no colonies formed following treatment. The two NaOCl groups, with 0 CFU/mL, were significantly different than the other four groups (p=0.009). Saline showed a trend towards higher CFU/mL than 50 µg/ml O3 (p=0.068). None of the other comparisons approached statistical significance (p=0.453 25 µg/ml O3, p=0.606 16 µg/ml O3, p=0.999 25 µg/ml O3 vs 50 µg/ml O3, p=0.990 16 µg/ml O3 vs 50 µg/ml O3, p=1.000 16 µg/ml O3 vs 25 µg/ml O3). Confocal imaging helped illustrate effects of irrigation and confirm CFU findings. Conclusion: The results of this study failed to reject the null hypothesis. There was a statistically significant difference in the E. faecalis biofilm remaining in the groups treated with ozonated water compared to those treated with NaOCl. However, there was a trend towards higher CFU/mL in the saline group compared to the 50µg/mL ozonated water group. According to this finding, future studies should evaluate the effects of higher concentrations of ozonated water against an established E. faecalis biofilm. In addition, other follow-up studies might include ozonated water’s effect on human cells, such as the stem cells of the apical papilla that are so critical to the success of regenerative endodontic procedures. Due to university and laboratory closures caused by the COVID-19 pandemic, this project was stopped short and an insufficient sample size did not allow for proper statistical power. Additional occasions should be run upon the university’s re-opening to allow for proper statistical power.
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    Long-term exposure to ambient air pollution and renal function in African Americans: the Jackson Heart Study
    (Springer Nature, 2019-06) Weaver, Anne M.; Wang, Yi; Wellenius, Gregory A.; Young, Bessie; Boyle, Luke D.; Hickson, DeMarc A.; Diamantidis, Clarissa J.; Environmental Health Science, School of Public Health
    Renal dysfunction is prevalent in the US among African Americans. Air pollution is associated with renal dysfunction in mostly white American populations, but has not been studied among African Americans. We evaluated cross-sectional associations between 1-year and 3-year fine particulate matter (PM2.5) and ozone (O3) concentrations, and renal function among 5090 African American participants in the Jackson Heart Study. We used mixed-effect linear regression to estimate associations between 1-year and 3-year PM2.5 and O3 and estimated glomerular filtration rate (eGFR), urine albumin/creatinine ratio (UACR), serum creatinine, and serum cystatin C, adjusting for: sociodemographic factors, health behaviors, and medical history and accounting for clustering by census tract. At baseline, JHS participants had mean age 55.4 years, and 63.8% were female; mean 1-year and 3-year PM2.5 concentrations were 12.2 and 12.4 µg/m3, and mean 1-year and 3-year O3 concentrations were 40.2 and 40.7 ppb, respectively. Approximately 6.5% of participants had reduced eGFR (< 60 mL/min/1.73m2) and 12.7% had elevated UACR (> 30 mg/g), both indicating impaired renal function. Annual and 3-year O3 concentrations were inversely associated with eGFR and positively associated with serum creatinine; annual and 3-year PM2.5 concentrations were inversely associated with UACR. We observed impaired renal function associated with increased O3 but not PM2.5 exposure among African Americans.
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    Smoggy with a Chance of Altruism: The Effects of Ozone Alerts on Outdoor Recreation and Driving in Atlanta
    (2014-02) Noonan, Douglas S.
    Metropolitan smog alerts are prominent public information campaigns designed to enhance public health and to curb driving and other emissions. Unlike many other voluntary information-based environmental policies, air quality alerts target household behavior via forecast information about ambient concentrations rather than firm or product characteristics. This paper explores behaviors with high emissions (driving) and with high exposure (outdoor recreation) and underscores the difference between altruistic and risk aversion motivations. Behavioral impacts are identified using the threshold nature of daily air quality forecasts. A regression discontinuity (RD) design finds elderly users and exercisers tend to curtail their use of a major park following smog alerts. The RD design also reveals that households do not drive less on smog alert days. Juxtaposing high emissions behavior with high exposure behavior in the same study highlights how public forecast information may better trigger some responses and struggle to trigger others.